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Sample records for spray pyrolysis method

  1. Fabrication of ZnO nanorod using spray-pyrolysis and chemical bath deposition method

    SciTech Connect

    Ramadhani, Muhammad F. Pasaribu, Maruli A. H. Yuliarto, Brian Nugraha

    2014-02-24

    ZnO thin films with nanorod structure were deposited using Ultrasonic Spray Pyrolysis method for seed growth, and Chemical Bath Deposition (CBD) for nanorod growth. High purity Zn-hydrate and Urea are used to control Ph were dissolved in ethanol and aqua bidest in Ultrasonic Spray Pyrolysis process. Glass substrate was placed above the heater plate of reaction chamber, and subsequently sprayed with the range duration of 5, 10 and 20 minutes at the temperatures of 3500 C. As for the Chemical Bath Deposition, the glass substrate with ZnO seed on the surface was immerse to Zn-hydrate, HMTA (Hexa Methylene Tetra Amine) and deionized water solution for duration of 3, 5 and 7 hour and temperatures of 600 C, washed in distilled water, dried, and annealed at 3500 C for an hour. The characterization of samples was carried out to reveal the surface morphology using Scanning Electron Microscopy (SEM). From the data, the combination of 5 minutes of Ultrasonic Spray Pyrolysis process and 3 hour of CBD has showed the best structure of nanorod. Meanwhile the longer Spraying process and CBD yield the bigger nanorod structure that have been made, and it makes the films more dense which make the nanorod collide each other and as a result produce unsymetric nanorod structure.

  2. Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

    SciTech Connect

    G, Sreeja V; Anila, E. I. R, Reshmi John, Manu Punnan; V, Sabitha P; Radhakrishnan, P.

    2014-10-15

    ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

  3. Nonlinear optical characterization of ZnS thin film synthesized by chemical spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    G, Sreeja V.; V, Sabitha P.; Anila, E. I.; R, Reshmi; John, Manu Punnan; Radhakrishnan, P.

    2014-10-01

    ZnS thin film was prepared by Chemical Spray Pyrolysis (CSP) method. The sample was characterized by X-ray diffraction method and Z scan technique. XRD pattern showed that ZnS thin film has hexagonal structure with an average size of about 5.6nm. The nonlinear optical properties of ZnS thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532nm. The Z-scan plot showed that the investigated ZnS thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated.

  4. Hydrogen-free spray pyrolysis chemical vapor deposition method for the carbon nanotube growth: Parametric studies

    NASA Astrophysics Data System (ADS)

    Ionescu, Mihnea Ioan; Zhang, Yong; Li, Ruying; Sun, Xueliang; Abou-Rachid, Hakima; Lussier, Louis-Simon

    2011-05-01

    Spray pyrolysis chemical vapor deposition (CVD) in the absence of hydrogen at low carrier gas flow rates has been used for the growth of carbon nanotubes (CNTs). A parametric study of the carbon nanotube growth has been conducted by optimizing various parameters such as temperature, injection speed, precursor volume, and catalyst concentration. Experimental observations and characterizations reveal that the growth rate, size and quality of the carbon nanotubes are significantly dependent on the reaction parameters. Scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy techniques were employed to characterize the morphology, structure and crystallinity of the carbon nanotubes. The synthesis process can be applied to both semiconducting silicon wafer and conducting substrates such as carbon microfibers and stainless steel plates. This approach promises great potential in building various nanodevices with different electron conducting requirements. In addition, the absence of hydrogen as a carrier gas and the relatively low synthesis temperature (typically 750 C) qualify the spray pyrolysis CVD method as a safe and easy way to scale up the CNT growth, which is applicable in industrial production.

  5. A Spray Pyrolysis Method to Grow Carbon Nanotubes on Carbon Fibres, Steel and Ceramic Bricks.

    PubMed

    Vilatela, Juan J; Rabanal, M E; Cervantes-Sodi, Felipe; Garca-Ruiz, Mximo; Jimnez-Rodrguez, Jos A; Reiband, Gerd; Terrones, Mauricio

    2015-04-01

    We demonstrate a spray pyrolysis method to grow carbon nanotubes (CNTs) with high degree of crystallinity, aspect ratio and degree of alignment on a variety of different substrates, such as conventional steel, carbon fibres (CF) and ceramics. The process consists in the chemical vapour deposition of both a thin SiO2 layer and CNTs that subsequently grow on this thin layer. After CNT growth, increases in specific surface by factors of 1000 and 30 for the steel and CF samples, respectively, are observed. CNTs growth on ceramic surfaces results in a surface resistance of 37.5 Ohm/sq. When using conventional steel as a rector tube, we observed CNTs growth rates of 0.6 g/min. Details of nanotube morphology and the growth mechanism are discussed. Since the method discussed here is highly versatile, it opens up a wide variety of applications in which specific substrates could be used in combination with CNTs. PMID:26353505

  6. Spray pyrolysis of CZTS nanoplatelets.

    PubMed

    Exarhos, S; Bozhilov, K N; Mangolini, L

    2014-10-01

    We demonstrate that copper-zinc-tin-sulphide nanoplatelets can be directly grown onto a molybdenum-coated substrate using spray pyrolysis starting from a mixture of metal thiocarbamates precursors. The structure and phase purity of the nanoplatelets is discussed in detail. PMID:25119262

  7. Production and characterization of submicron hematite (?-Fe2O3) particles by ultrasonic spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    K?rc?, Burak; Ebin, Burak; Grmen, Sebahattin

    2013-12-01

    The ultrasonic spray pyrolysis (USP) method has been used to prepare submicron hematite (?-Fe2O3) particles using two different industrial pickling solutions of iron chloride (41 g/L FeCl2 and 54 g/L FeCl3) Particles were obtained by thermal decomposition of generated aerosols from precursor solutions using 1.7 MHz ultrasonic atomizer. Reaction temperature was set up at 800 C and aerosol droplets were carried into the heated zone by 0.7 L/min air flow rate. X-Ray Diffraction (XRD) studies were used to determine the crystal structure and crystallite size of the particles. Results indicate that patterns correspond to hematite phase with rhombohedral crystal structure (space group: R3c). The crystallite sizes of particles prepared from FeCl2 and FeCl3 solutions that were calculated from Scherrer equation are 59 and 33 nm, respectively. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) investigations give detailed information about particle size, morphology and composition. SEM micrographs show that hematite nanoparticles aggregate and formed spherical secondary particles in submicron range.

  8. Development of Ag/WO3/ITO thin film memristor using spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Dongale, T. D.; Mohite, S. V.; Bagade, A. A.; Gaikwad, P. K.; Patil, P. S.; Kamat, R. K.; Rajpure, K. Y.

    2015-11-01

    The unique nonlinear relationship between charge and magnetic flux along with the pinched hysteresis loop in I- V plane provide memory with resistance combinations of attribute to Memristor which lead to their novel applications in non volatile memory, nonlinear dynamics, analog computations and neuromorphic biological systems etc. The present paper reports development of Ag/WO3/ITO thin film memristor device using spray pyrolysis method. The structural, morphological and electrical properties of the thin film memristor device are further characterized using x-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and semiconductor device analyzer. The memristor is simulated using linear dopent drift model to ascertain the theoretical and experimental conformations. For the simulation purpose, the width of doped region (w) limited to the interval [0, D] is considered as a state variable along with the window function characterized by the equation f ( x) = w (1 - w). The reported memristor device exhibits the symmetric pinched hysteresis loop in I- V plane within the low operating voltage (1 V). [Figure not available: see fulltext.

  9. Deposition of Ni-CGO composite anodes by electrostatic assisted ultrasonic spray pyrolysis method

    SciTech Connect

    Chen, J.-C.; Chang, C.-L.; Hsu, C.-S.; Hwang, B.-H. . E-mail: zorro@mail.nsysu.edu.tw

    2007-09-04

    Deposition of composite films of Ni and Gd-doped ceria was carried out using the electrostatic assisted ultrasonic spray pyrolysis method for the first time. The composite films were highly homogeneous, as revealed by element mapping via energy-dispersive spectrometry. Scanning electron microscope examinations revealed that deposition temperature and electric field strength had profound influence on resultant microstructure, while composition of the precursor solution had little effect. A highly porous cauliflower structure ideal for solid oxide fuel cell anode performance was obtained with a deposition temperature of 450 deg. C under an electric field introduced by an applied voltage of 12 kV. Films obtained with a lower deposition temperature of 250 deg. C or a higher applied voltage of 15 kV resulted in denser films with low porosity, while lower applied voltages of 7 or 5 kV resulted in thinner or discontinuous films due to the insufficient electrostatic attraction on the aerosol droplets. As revealed by AC impedance measurement, the area specific resistances of the Ni-CGO anode with porous cauliflower structure were rather low and a value of 0.09 {omega} cm{sup 2} at 550 deg. C was obtained.

  10. Structural and physical properties of boron doped ZnO films prepared by chemical spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Kerli, S.; Alver, U.; Tanriverdi, A.; Avar, B.

    2015-11-01

    In this work, ZnO and boron doped ZnO (ZnO:B) thin films were produced by chemical spray pyrolysis method. ZnO and ZnO:B films were obtained onto glass substrates at 450C by spray pyrolysis method and the physical properties of those films were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectrometer (UV) and four probe technique. XRD measurements show that all films have hexagonal wurtzite structure and all films grow preferentially along (002) direction. Morphologies of the films were examined by using a scanning electron microscopy and it was observed that almost all films were quite intense with a regular structure. Optical measurements showed that the band gap energies of the films increased with boron concentrations. The resistances of the B-doped ZnO films were measured by four probe method and resistances of films initially decreased to its minimum 1 at% boron doping and then it increased again with increasing B concentration. It was also observed that that boron doping increased the activation energies of the films.

  11. Structural, morphological and optical properties of CuAlS 2 films deposited by spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Caglar, Mujdat; Ilican, Saliha; Caglar, Yasemin

    2008-03-01

    The structural, morphological and optical properties of CuAlS2 films deposited by spray pyrolysis method have been investigated. CuAlS2 in the form of films is prepared at different deposition conditions by a simple and economical spray pyrolysis method. The structural, surface morphology and optical properties of the films were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and absorbance spectra, respectively. The films were polycrystalline, crystallized in a tetragonal structure, and are preferentially orientated along the (1 1 2) direction. Grain size values, dislocation density, and d% error of CuAlS2 films were calculated. The optical band gap of the CuAlS2 film was found to be 3.45 eV. The optical constants such as refractive index, extinction coefficient and dielectric constants of the CuAlS2 film were determined. The refractive index dispersion curve of the film obeys the single oscillator model. Optical dispersion parameters Eo and Ed developed by Wemple-DiDomenico were calculated and found to be 3.562 and 12.590 eV.

  12. Using Modified Spray Pyrolysis-Calcination Method and Their Magnetic Properties

    NASA Astrophysics Data System (ADS)

    An, Guk-Hwan; Hwang, Tae-Yeon; Choa, Yong-Ho; Shin, Kyoosik

    2014-09-01

    Strontium hexaferrite (SrFe12O19, SrM) suitable for high-performance permanent magnet applications was synthesized by salt-assisted ultrasonic spray pyrolysis (SA-USP) and subsequent calcination. To control the particle size, the intermediate phase of SrM was collected by SA-USP and various sizes of SrM were obtained by calcining the as-prepared sample at temperatures ranging from 800C to 1050C. The synthesized SrM was magnetically aligned by using an external magnetic field to improve remanence. The synthesized particles were of nano- to submicron scale and nonagglomerated. The magnetic properties and squareness of the material depended on the particle size and distribution. Additionally, the NaCl added during synthesis facilitated the formation of nonagglomerated particles, while enhancing and controlling particle growth. The optimum magnetic properties were achieved at calcination temperature of 1000C, resulting in coercivity of 5646 Oe, saturation magnetization of 73.3 emu/g, and remanence of 59.1 emu/g (80.6% of M s).

  13. Producing Quantum Dots by Spray Pyrolysis

    NASA Technical Reports Server (NTRS)

    Banger, Kulbinder; Jin, Michael H.; Hepp, Aloysius

    2006-01-01

    An improved process for making nanocrystallites, commonly denoted quantum dots (QDs), is based on spray pyrolysis. Unlike the process used heretofore, the improved process is amenable to mass production of either passivated or non-passivated QDs, with computer control to ensure near uniformity of size.

  14. Thin Film Electrode Materials Li4Ti5O12 and LiCoO2 Prepared by Spray Pyrolysis Method

    NASA Astrophysics Data System (ADS)

    Takahashi, M.; Tani, J.; Kido, H.; Hayashi, A.; Tadanaga, K.; Tatsumisago, M.

    2011-05-01

    The Li4Ti5O12 and the LiCoO2 have been considered as promising candidates of electrode materials for all-solid-state lithium secondary batteries. The spray pyrolysis method is a useful economical technique to prepare various thicknesses of oxide films though have not been intensively studied for fabrication of thin film lithium batteries. Thin films of Li4Ti5O12 and LiCoO2 electrode materials about 100-400 nm were prepared on quartz and gold substrates by the spray pyrolysis method by using Liacac and, TiO(acac)4 or Co(acac)3 with DMF solvent as starting materials. Electric properties as electrode materials for lithium batteries were estimated by using 3 probe liquid cells with liquid electrolyte LiPF6 in EC-DMC and Li metal as reference and counter electrodes. Structure and morphology of the films were investigated by XRD and SEM. Crystalline Li4Ti5O12 and LiCoO2 thin films were found to be prepared over 700 °C of substrate temperature. Cyclic voltammograms of the Li4Ti5O12 electrode thin films showed sharp oxidation and reduction peaks around 1.6 and 1.5 V, respectively. Charge-discharge curves for both Li4Ti5O12 and LiCoO2 electrode thin films showed discharge plateaus around 1.4 and 3.8 V with about 80 mAhg-1 of capacity. These results showed that these electrode thin films prepared by the spray pyrolysis method are electrochemically active and spray pyrolysis method is a promising technique to prepare thin film electrode materials.

  15. Production and characterization of submicron hematite (??Fe{sub 2}O{sub 3}) particles by ultrasonic spray pyrolysis method

    SciTech Connect

    K?rc?, Burak; Ebin, Burak; Grmen, Sebahattin

    2013-12-16

    The ultrasonic spray pyrolysis (USP) method has been used to prepare submicron hematite (??Fe{sub 2}O{sub 3}) particles using two different industrial pickling solutions of iron chloride (41 g/L FeCl{sub 2} and 54 g/L FeCl{sub 3}) Particles were obtained by thermal decomposition of generated aerosols from precursor solutions using 1.7 MHz ultrasonic atomizer. Reaction temperature was set up at 800 C and aerosol droplets were carried into the heated zone by 0.7 L/min air flow rate. X-Ray Diffraction (XRD) studies were used to determine the crystal structure and crystallite size of the particles. Results indicate that patterns correspond to hematite phase with rhombohedral crystal structure (space group: R3c). The crystallite sizes of particles prepared from FeCl{sub 2} and FeCl{sub 3} solutions that were calculated from Scherrer equation are 59 and 33 nm, respectively. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) investigations give detailed information about particle size, morphology and composition. SEM micrographs show that hematite nanoparticles aggregate and formed spherical secondary particles in submicron range.

  16. Structural, Morphological, Electrical and Magnetic Properties of Nanostructured CoFe Thin Films Prepared by Spray Pyrolysis Deposition Method

    NASA Astrophysics Data System (ADS)

    Amirabadizadeh, Ahmad; Sarhaddi, Reza; Vahedipanah, Zahra; Mardani, Reza

    2015-08-01

    Nanostructured CoFe thin films were prepared on the glass substrates by spray pyrolysis deposition (SPD) method. The as-deposited films were separately annealed at 500°C in ambient air and hydrogen atmospheres to investigate the effect of annealing atmosphere on different properties of the deposited films. Structural, morphological, magnetic and electrical properties of annealed thin films were investigated by the X-ray diffractometer (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and four-point probe measurements, respectively. XRD patterns show that by changing the annealing atmosphere from ambient air to hydrogen, the crystal structure transformed from cubic spinel phase (Fd-3m) to cubic CsCl-type phase (Pm-3m). SEM images demonstrated that the morphology, grain size and thickness of annealed thin films depend greatly on the atmosphere type. Thickness of the films annealed in ambient air and hydrogen atmosphere were 378 and 356 nm, respectively. The morphology of the films changes from small sized granular for the ambient air-annealed films to coral-like structures for the hydrogen atmosphere annealed films. The magnetic properties of the annealed thin films depend on the annealing atmosphere, the applied field directions and film microstructural properties. Hydrogen annealing induced a perpendicular magnetic anisotropy in CoFe thin films. Room temperature hysteresis measurements show soft magnetic behavior of the hydrogen atmosphere annealed CoFe films in the perpendicular direction suggested its application in perpendicular magnetic recording media.

  17. Spray pyrolysis of CuIn(S,Se)2 solar cells with 5.9% efficiency: a method to prevent Mo oxidation in ambient atmosphere.

    PubMed

    Ho, John C W; Zhang, Tianliang; Lee, Kian Keat; Batabyal, Sudip K; Tok, Alfred I Y; Wong, Lydia H

    2014-05-14

    Direct spray pyrolysis to form CuInS2 (CIS) on molybdenum substrate in ambient environment has been a challenge because of the ease of Mo oxidation at low temperatures. MoO2 formation affects the wettability of precursor solution during spray pyrolysis, which degrades the uniformity of CIS film and acts as a resistive layer for carrier transport. In this paper, Mo oxidation was prevented by using excess sulfur in the precursor solution under a gradual heating and spray process. A thin precursor layer was initially deposited as a barrier layer to prevent oxygen adsorption on Mo surface before the temperature was increased further to form polycrystalline CuInS2. The CuIn(S,Se)2 (CISSe) device fabricated from selenization of the spray-pyrolyzed CIS film exhibited a power conversion efficiency (PCE) of 5.9%. The simple spray method proposed here can be used to deposit a variety of Cu-based chalcopyrite precursor to produce high-quality thin film solar cells. PMID:24697706

  18. Structural, optical and electrical properties of molybdenum-doped cadmium oxide thin films prepared by spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Kumaravel, R.; Bhuvaneswari, S.; Ramamurthi, K.; Krishnakumar, V.

    2012-11-01

    Molybdenum-doped cadmium oxide films were prepared by a spray pyrolysis technique at a substrate temperature of 300 °C. The effect of doping on structural, electrical and optical properties were studied. X-ray analysis shows that the undoped CdO films are preferentially oriented along the (111) crystallographic direction. Molybdenum doping concentration increases the films' packing density and reorients the crystallites along the (200) plane. A minimum resistivity of 4.68×10-4 Ω cm with a maximum mobility of 75 cm2 V-1 s-1 is achieved when the CdO film is doped with 0.5 wt.% Mo. The band-gap value is found to increase with doping and reaches a maximum of 2.56 eV for 0.75 wt.% as compared to undoped films of 2.2 eV.

  19. Magnetic-luminescent spherical particles synthesized by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Michel, Norma L.; Flores, Dora L.; Hirata, Gustavo A.

    2015-07-01

    The combination of magnetic and luminescent properties in a single particle system, opens-up a wide range of potential applications in biotechnology and biomedicine. In this work, we performed the synthesis of magnetic-luminescent Gd2O3:Eu3+@Fe2O3 particles by ultrasonic spray pyrolysis performed in a tubular furnace. In order to achieve the composite formation, commercial superparamagnetic Fe3O4 nanoparticles were coated with a luminescent Eu3+-doped Gd2O3 shell in a low-cost one-step process. The spray pyrolysis method yields deagglomerated spherical shape magneto/luminescent particles. The photoluminescence spectra under UV excitation (λExc = 265 nm) of the magnetic Gd2O3:Eu3+@Fe2O3 compound showed the characteristic red emission of Eu3+ (λEm = 612 nm). This magneto/luminescent system will find applications in biomedicine and biotechnology.

  20. Improved superconducting properties of MgB2 thin films fabricated by ultrasonic spray pyrolysis method at high temperature

    NASA Astrophysics Data System (ADS)

    Yakinci, M. Eyyuphan; Yakinci, Z. Deniz; Aksan, M. Ali; Balci, Yakup

    2012-12-01

    High quality MgB2 superconducting thin films have been successfully prepared by 2.4 MHz ultrasonic spray pyrolysis (USP) system on single crystal Al2O3 (0 0 1) substrates. The microstructure, electrical and magnetic properties of approximately 500-600 nm thick films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) in conjunction with the energy dispersive X-ray analysis (EDX), resistance versus temperature (R-T) and magnetization measurements (M-H) under different magnetic fields and transport critical current density (Jc). Films were first heat treated in situ in the spraying chamber with an extra Mg powder during deposition to compensate excess evaporation of Mg from the films and then additionally heat treated in Ar atmosphere at 700 C for a short time. According to the results obtained, orientation on any particular direction for the crystal growth was not seen. Homogeneous, highly dense and highly smooth surface morphology and low resistance have been achieved under optimum conditions. Optimally treated films exhibited relatively high transport critical current density of 2.37 105 A cm-2. These results have been also compared with the Jcmag results calculated from the M-H curves. The electrical resistance property of the best samples was obtained to be 39.5 and 37.4 K for Tc and Tzero, respectively.

  1. Porous carbon powders prepared by ultrasonic spray pyrolysis.

    PubMed

    Skrabalak, Sara E; Suslick, Kenneth S

    2006-10-01

    New, thermally robust meso- and macroporous carbon powders were prepared by ultrasonic spray pyrolysis (USP) of aqueous solutions using an inexpensive high-frequency ultrasound generator from a household humidifier. We choose our molecular precursors rationally, so that the expected decomposition pathways produce only remnant carbon atoms. Specifically, our rational design criterion led to halo-organic carboxylate salts, whose pyrolysis yields well-defined carbon solids with a temporary template being generated in situ, simply an inorganic salt, which is easily dissolved during aqueous workup. The materials have been characterized by SEM, TEM, XRD, 13C NMR MAS, XPS, FTIR spectroscopy, and BET surface area measurements. Changing the alkali metal alters the morphology and pore structure of the final material, which can be explained in terms of the observed differences in the DSC and TGA of the various precursors. This preparatory method provides an extremely facile and versatile method for the generation of meso- and macroporous carbons. PMID:17002346

  2. Band positions and photoelectrochemical properties of Cu2ZnSnS4 thin films by the ultrasonic spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Huang, Sheng; Luo, Wenjun; Zou, Zhigang

    2013-06-01

    Cu2ZnSnS4 (CZTS) films were prepared by ultrasonic spray pyrolysis on FTO (SnO2?:?F on glass) substrates. The effect of substrate temperatures on the phases, morphologies and photoelectrochemical properties of CZTS films was investigated. X-ray diffraction, Raman spectrum and energy-dispersive spectrometry were used to confirm the phases of the CZTS films. The samples at 400 and 450 C exhibited a higher photocurrent than the samples at 350 and 500 C. Moreover, the band positions of CZTS were measured by a facile Mott-Schottky method for the first time. Different from the previous calculation and experimental data, the conduction band position of CZTS was 0.26 eV higher than that of CdS. The results can explain well the low open circuit voltage of a CZTS-based solar cell and offer guidance to improving CZTS solar cells.

  3. Photoluminescence of spray pyrolysis deposited ZnO nanorods

    PubMed Central

    2011-01-01

    Photoluminescence of highly structured ZnO layers comprising well-shaped hexagonal rods is presented. The ZnO rods (length 500-1,000 nm, diameter 100-300 nm) were grown in air onto a preheated soda-lime glass (SGL) or ITO/SGL substrate by low-cost chemical spray pyrolysis method using zinc chloride precursor solutions and growth temperatures in the range of 450-550C. We report the effect of the variation in deposition parameters (substrate type, growth temperature, spray rate, solvent type) on the photoluminescence properties of the spray-deposited ZnO nanorods. A dominant near band edge (NBE) emission is observed at 300 K and at 10 K. High-resolution photoluminescence measurements at 10 K reveal fine structure of the NBE band with the dominant peaks related to the bound exciton transitions. It is found that all studied technological parameters affect the excitonic photoluminescence in ZnO nanorods. PACS: 78.55.Et, 81.15.Rs, 61.46.Km PMID:21711895

  4. Effect of fuel rate and annealing process of LiFePO{sub 4} cathode material for Li-ion batteries synthesized by flame spray pyrolysis method

    SciTech Connect

    Halim, Abdul; Setyawan, Heru; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

    2014-02-24

    In this study the effect of fuel rate and annealing on particle formation of LiFePO{sub 4} as battery cathode using flame spray pyrolysis method was investigated numerically and experimentally. Numerical study was done using ANSYS FLUENT program. In experimentally, LiFePO{sub 4} was synthesized from inorganic aqueous solution followed by annealing. LPG was used as fuel and air was used as oxidizer and carrier gas. Annealing process attempted in inert atmosphere at 700C for 240 min. Numerical result showed that the increase of fuel rate caused the increase of flame temperature. Microscopic observation using Scanning Electron Microscopy (SEM) revealed that all particles have sphere and polydisperse. Increasing fuel rate caused decreasing particle size and increasing particles crystallinity. This phenomenon attributed to the flame temperature. However, all produced particles still have more amorphous phase. Therefore, annealing needed to increase particles crystallinity. Fourier Transform Infrared (FTIR) analysis showed that all particles have PO4 function group. Increasing fuel rate led to the increase of infrared spectrum absorption corresponding to the increase of particles crystallinity. This result indicated that phosphate group vibrated easily in crystalline phase. From Electrochemical Impedance Spectroscopy (EIS) analysis, annealing can cause the increase of Li{sup +} diffusivity. The diffusivity coefficient of without and with annealing particles were 6.8439910{sup ?10} and 8.5988810{sup ?10} cm{sup 2} s{sup ?1}, respectively.

  5. Fabricate heterojunction diode by using the modified spray pyrolysis method to deposit nickel-lithium oxide on indium tin oxide substrate.

    PubMed

    Wu, Chia-Ching; Yang, Cheng-Fu

    2013-06-12

    P-type lithium-doped nickel oxide (p-LNiO) thin films were deposited on an n-type indium tin oxide (ITO) glass substrate using the modified spray pyrolysis method (SPM), to fabricate a transparent p-n heterojunction diode. The structural, optical, and electrical properties of the p-LNiO and ITO thin films and the p-LNiO/n-ITO heterojunction diode were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy, Hall effect measurement, and current-voltage (I-V) measurements. The nonlinear and rectifying I-V properties confirmed that a heterojunction diode characteristic was successfully formed in the p-LNiO/n-ITO (p-n) structure. The I-V characteristic was dominated by space-charge-limited current (SCLC), and the Anderson model demonstrated that band alignment existed in the p-LNiO/n-ITO heterojunction diode. PMID:23683053

  6. Effects of ultraviolet light on B-doped CdS thin films prepared by spray pyrolysis method using perfume atomizer

    NASA Astrophysics Data System (ADS)

    Novruzov, V. D.; Keskenler, E. F.; Tomakin, M.; Kahraman, S.; Gorur, O.

    2013-09-01

    Boron doped CdS thin films were deposited by spray pyrolysis method using perfume atomizer. The effects of ultraviolet light on the structural, optical and electrical properties of B-doped CdS thin films were investigated as a function of dopant concentration (B/Cd). X-ray diffraction studies showed that all samples were polycrystalline nature with hexagonal structure. It was determined that the preferred orientation of non-illuminated samples changes from (1 0 1) to (0 0 2) with B concentration. The c lattice constant of films decreases from 6.810 Å to 6.661 Å with boron doping. The XRD peak intensity increased with the illumination for almost all the samples. The lattice parameters of B-doped samples remained nearly constant after illumination. It was found that the optical transmittance, photoluminescence spectra, resistivity and carrier concentration of the B-doped samples are stable after the illumination with UV light. Also the effects of UV light on B-doped CdS/Cu2S solar cell were investigated and it was determined that photoelectrical parameters of B-doped solar cell were more durable against the UV light.

  7. Synthesis of lithium cobalt oxide using low-pressure spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hidayat, Darmawan; Joni, I. Made; Setianto, Panatarani, Camellia; Okuyama, Kikuo

    2013-09-01

    A low pressure spray pyrolysis (LPSP) process was applied to synthesize crystalline lithium cobalt oxide as a battery cathode material via a liquid route. The effects of temperature and pressure of reactor on the synthesized particles characteristics were systematically investigated. Reactor temperatures of 800, 1000 and 1200 C with pressures of 760 and 300 Torr were applied as operating conditions. The characterizations results show that the synthesized particles were highly crystalline and nearly spherical in shape. The results concluded that the low-pressure spray pyrolysis method has ability in control of particles morphology, crystallinity and atomic lithium-to-cobalt ratio.

  8. Flame spray pyrolysis for sensing at the nanoscale.

    PubMed

    Kemmler, J A; Pokhrel, S; Mdler, L; Weimar, U; Barsan, N

    2013-11-01

    Progress in developing novel gas sensors based on semiconducting metal oxides (SMOX) has been hindered by the cumbersome fabrication technologies currently employed. They involve time intensive synthesis procedures for gaining sensitive materials and preparation of the inks employed for realizing sensing layers. In this paper we review the opportunities offered by the relatively young method of flame spray pyrolysis, with which it is possible not only to synthesize a broad selection of SMOX in pure or doped form, but also to simultaneously deposit thick and highly porous gas sensitive films on a variety of substrates. In less than ten years the properties of nine base materials have been evaluated for all most relevant target gases and the obtained results are promising for future development. PMID:24113649

  9. Continuous Synthesis of Doped Pyrochlore Materials by Spray Pyrolysis for Auto-thermal Reforming Applications

    NASA Astrophysics Data System (ADS)

    Yancey, Jonathan

    The use of a spray-pyrolysis method is studied for the continuous synthesis of refractory oxide reforming catalyst for the conversion of hydrocarbon fuels to H2 and CO at 900C. Nickel- and rhodium-doped zirconate pyrochlore materials with the formulas La1.89Ni2.81Y 0.25Ca0.11Zr1.47 and La1.89Rh 1.09Y0.25Ca0.11Zr1.641 were synthesized using the spray pyrolysis method. Both Pechini and glycine-nitrate precursor solutions were used in order to control the particle morphology, crystallinity, and surface area of the catalyst powder. Samples synthesized by the Pechini solution required post-synthesis heat treatment to 1000 C for 2 hours to form the fully-crystalline pyrochlore phase. Both the Ni- and Rh-doped compositions formed by the spray-pyrolysis method performed as reported elsewhere for powder produced by solid-state and Pechini bulk methods. The use of the glycine-nitrate precursor solution in the spray-pyrolysis resulted in the formation of fully crystalline pyrochlore catalyst for the Ni-doped composition without any additional high temperature treatment. The Rh-doped catalysts synthesized from the glycine-nitrate precursor did not form a fully crystalline material directly from the spray-pyrolysis process, but required a further thermal treatment to 800 C for 8 hours to transform the powder and burn-off excess carbon remaining from the synthesis process. Rapid catalyst aging tests for the Rh-doped catalysts synthesized by spray-pyrolysis (using either the Pechini and glycine-nitrate precursor solutions) produced stable and active catalysts achieving equilibrium hydrogen yield of 90% for 15 hours. To conclude, the work showed that through proper chemical design of the precursor system, a high surface area, chemically active, and stable zirconate pyrochlore catalyst could be synthesized efficiently by the spray-pyrolysis method developed.

  10. Investigations of AlGaN/GaN MOS-HEMT with Al2O3 deposition by ultrasonic spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Chou, Bo-Yi; Hsu, Wei-Chou; Liu, Han-Yin; Lee, Ching-Sung; Wu, Yu-Sheng; Sun, Wen-Ching; Wei, Sung-Yen; Yu, Sheng-Min; Chiang, Meng-Hsueh

    2015-01-01

    This work investigates Al2O3/AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) grown on SiC substrate by using the non-vacuum ultrasonic spray pyrolysis deposition (USPD) method. The Al2O3 was deposited as gate dielectric and surface passivation simultaneously to effectively suppress gate leakage current, enhance output current density, reduce RF drain current collapse, and improve temperature-dependent stabilities performance. The present MOS-HEMT design has shown improved device performances with respect to a Schottky-gate HEMT, including drain-source saturation current density at zero gate bias (IDSS: 337.6 mA mm-1 → 462.9 mA mm-1), gate-voltage swing (GVS: 1.55 V → 2.92 V), two-terminal gate-drain breakdown voltage (BVGD: -103.8 V → -183.5 V), unity-gain cut-off frequency (fT: 11.3 GHz → 17.7 GHz), maximum oscillation frequency (fmax: 14.2 GHz → 19.1 GHz), and power added effective (P.A.E.: 25.1% → 43.6%). The bias conditions for measuring fT and fmax of the studied MOS-HEMT (Schottky-gate HEMT) are VGS = -2.5 (-2) V and VDS = 7 V. The corresponding VGS and VDS biases are -2.5 (-2) V and 15 V for measuring the P.A.E. characteristic. Moreover, small capacitance-voltage (C-V) hysteresis is obtained in the Al2O3-MOS structure by using USPD. Temperature-dependent characteristics of the present designs at 300-480 K are also studied.

  11. Synthesis and characterization of YSZ by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Jadhav, L. D.; Jamale, A. P.; Bharadwaj, S. R.; Varma, Salil; Bhosale, C. H.

    2012-10-01

    The conventional zirconium based yttria stabilized zirconia (YSZ) electrolyte has been synthesized from aqueous solution by cost effective air atomized spray pyrolysis technique (SPT). The films show well developed dense, nanocrystalline material. The thermal analysis of zirconyl nitrate reveals the possibility of crystalline YSZ film formation only above 400 C, which is confirmed from the XRD pattern. The activation energy of 1.14 eV clarifies its conductivity behavior, verified from DC and AC conductivity measurements.

  12. Fabrication of functional nanomaterials using flame assisted spray pyrolysis

    SciTech Connect

    Purwanto, Agus

    2014-02-24

    Flame assisted spray pyrolysis (FASP) is a class of synthesis method for nanomaterials fabrication. The ability to control nanomaterials characteristics and easy to be-scaled up are the main features of FASP. The crystallinity and particles size of the prepared nanomaterials can be easily controlled by variation of fuel flow rate. The precursor concentration, carrier gas flow rate, and carrier gas can be also used to control the prepared nanomaterials. Energy related nanomaterials preparation uses as the example case in FASP application. These material are yttrium aluminum garnet (YAG:Ce) and tungsten oxide (WO{sub 3}). It needs strategies to produce these materials into nano-sized order. YAG:Ce nanoparticles only can be synthesized by FASP using the urea addition. The decomposition of urea under high temperature of flame promotes the breakage of YAG:Ce particles into nanoparticles. In the preparation of WO{sub 3}, the high temperature flame can be used to gasify WO{sub 3} solid material. As a result, WO{sub 3} nanoparticles can be prepared easily. Generally, to produce nanoparticles via FASP method, the boiling point of the material is important to determine the strategy which will be used.

  13. Near field behavior of SnO(2) particle-layer deposited on standard optical fiber by electrostatic spray pyrolysis method.

    PubMed

    Cusano, A; Pilla, P; Consales, M; Pisco, M; Cutolo, A; Buosciolo, A; Giordano, M

    2007-04-16

    We report the emergent optical near field profiles from standard single mode optical fibers on the cleaved end of which were deposited particle layers of SnO(2). The layers, composed of micron and sub-micron sized particles, were deposited by means of Electrostatic Spray Pyrolysis (ESP) technique. Powerful analytical tools such as Atomic Force Microscopy (AFM) and Scanning Near-field Optical Microscopy (SNOM) were used to obtain simultaneously the SnO(2) layers topography and the related optical near field intensity distribution, when the fiber-substrate is illuminated by a light radiation in NIR range. We show that isolated microstructures, positioned in correspondence of the fiber core, reveal highly unusual capability of locally enhancing the collected optical near field. The observed phenomenon leads to new concepts of fiber optic chemical sensors and in fiber microsystems as well. PMID:19532764

  14. Magnetic and porous nanospheres from ultrasonic spray pyrolysis.

    PubMed

    Suh, Won Hyuk; Suslick, Kenneth S

    2005-08-31

    We have used an inexpensive high-frequency ultrasound generator from a household humidifier to create a useful source for ultrasonic spray pyrolysis and produced submicrometer silica particles that are porous on the nanometer scale. By using two heated zones, we first initiate polymerization of organic monomers in the presence of silica colloid, which creates in situ a composite of silica with an organic polymer, followed by a second heating to pyrolyze and remove the polymer. The morphology and surface area of the final porous silica are controlled by varying the silica-to-organic monomer ratio. In a single flow process, ferromagnetic cobalt nanoparticles can be easily encapsulated in the porous silica, and the resulting nanospheres are extremely resistant to air oxidation. Products were characterized by SEM, (S)TEM, EDS, XPS, and SQUID. PMID:16117540

  15. SnS2 Thin Film Deposition by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Yahia Jaber, Abdallah; Noaiman Alamri, Saleh; Salah Aida, Mohammed

    2012-06-01

    Tin disulfide (SnS2) thin films have been synthesized using a simplified spray pyrolysis technique using a perfume atomizer. The films were deposited using two different solutions prepared by the dilution of SnCl2 and thiourea in distilled water and in methanol. The obtained films have a microcrystalline structure. The film deposited using methanol as the solvent is nearly stochiometric SnS2 with a spinel phase having a (001) preferential orientation. The film prepared with an aqueous solution is Sn-rich. Scanning electronic microscopy (SEM) images reveal that the film deposited with the aqueous solution is rough and is formed with large wires. However, the film deposited with methanol is dense and smooth. Conductivity measurements indicate that the aqueous solution leads to an n-type semiconductor, while methanol leads to a p-type semiconductor.

  16. Titania by spray pyrolysis for photocatalytic destruction of organics in aqueous solutions

    SciTech Connect

    Fotou, G.P.; Himebaugh, L.; Kodas, T.T.; Wu, M.

    1996-12-31

    In this study, the potential of spray pyrolysis and spray calcination for the synthesis of effective titanium dioxide photocatalysts is explored. The product titanium dioxide powders were used in the photoassisted oxidation of salicylic acid in aqueous solutions. Titania particles were produced by spray pyrolysis of dihydroxybis titanium solutions in water at concentrations between 20 to 70% by volume at temperatures from 500 to 1100{degrees}C. Powders were made by spray calcination of titanium hydrolysate solutions at temperatures from 700 to 900 {degrees}C. Spray pyrolysis produced titania particles which were partially hollow. Spray calcination resulted in agglomerates which consisted of 15 nm primary particles that showed high photoactivity in the photooxidation of aqueous salicylic acid solutions. Doping with palladium oxide or ruthenium oxides did not improve the photocatalytic activity of these powders. 6 refs., 3 figs.

  17. Decoration of crumpled rGO sheets with Ag nanoparticles by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Papailias, I.; Giannouri, M.; Trapalis, A.; Todorova, N.; Giannakopoulou, T.; Boukos, N.; Lekakou, C.

    2015-12-01

    In this work, crumpled reduced graphene oxide (rGO) nanostructures were produced using spray pyrolysis technique. Graphite oxide (GtO) prepared through a modified Hummers method was used as starting material. Water dispersions of graphene oxide (GO) were prepared and sprayed in a tube furnace at 300 C, 500 C and 700 C using Argon (Ar) as carrier gas. Also, precursor dispersions with different AgNO3 concentrations were processed at the same conditions. During the treatment, the sprayed droplets underwent rapid heating and then gradual cooling until the exit of the oven, where crumpled rGO and Ag/rGO powders were collected. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and FT-IR spectroscopy. It was established that the crumpling of the nanosheets was slightly affected by the increase of the process temperature. Crumpled morphologies were obtained even at low temperature of 300 C. In contrast, the degree of GO reduction was temperature dependent and increased with the increase of the temperature. The incorporation of Ag nanoparticles was evidenced by the XRD and TEM analysis with the size of the Ag nanoparticles to grow as the concentration of AgNO3 and/or the process temperature increased. SERS effect in the Raman spectra of the Ag/rGO materials was observed that reached a maximum at 500 C. Spray pyrolysis was suggested as a simple, controllable and scalable route for the instantaneous crumpling, reduction and decoration of GO nanosheets with metal/metal oxide nanoparticles.

  18. Methods and apparatuses for preparing upgraded pyrolysis oil

    DOEpatents

    Brandvold, Timothy A; Baird, Lance Awender; Frey, Stanley Joseph

    2013-10-01

    Methods and apparatuses for preparing upgraded pyrolysis oil are provided herein. In an embodiment, a method of preparing upgraded pyrolysis oil includes providing a biomass-derived pyrolysis oil stream having an original oxygen content. The biomass-derived pyrolysis oil stream is hydrodeoxygenated under catalysis in the presence of hydrogen to form a hydrodeoxygenated pyrolysis oil stream comprising a cyclic paraffin component. At least a portion of the hydrodeoxygenated pyrolysis oil stream is dehydrogenated under catalysis to form the upgraded pyrolysis oil.

  19. Effect of precursor concentration and spray pyrolysis temperature upon hydroxyapatite particle size and density.

    PubMed

    Cho, Jung Sang; Lee, Jeong-Cheol; Rhee, Sang-Hoon

    2016-02-01

    In the synthesis of hydroxyapatite powders by spray pyrolysis, control of the particle size was investigated by varying the initial concentration of the precursor solution and the pyrolysis temperature. Calcium phosphate solutions (Ca/P ratio of 1.67) with a range of concentrations from 0.1 to 2.0 mol/L were prepared by dissolving calcium nitrate tetrahydrate and diammonium hydrogen phosphate in deionized water and subsequently adding nitric acid. Hydroxyapatite powders were then synthesized by spray pyrolysis at 900C and at 1500C, using these calcium phosphate precursor solutions, under the fixed carrier gas flow rate of 10 L/min. The particle size decreased as the precursor concentration decreased and the spray pyrolysis temperature increased. Sinterability tests conducted at 1100C for 1 h showed that the smaller and denser the particles were, the higher the relative densities were of sintered hydroxyapatite disks formed from these particles. The practical implication of these results is that highly sinterable small and dense hydroxyapatite particles can be synthesized by means of spray pyrolysis using a low-concentration precursor solution and a high pyrolysis temperature under a fixed carrier gas flow rate. 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 422-430, 2016. PMID:25891158

  20. Synthesis of TiO{sub 2} core/RuO{sub 2} shell particles using multistep ultrasonic spray pyrolysis

    SciTech Connect

    Stopic, Srecko; Friedrich, Bernd; Schroeder, Michael; Weirich, Thomas E.

    2013-09-01

    Graphical abstract: - Highlights: • TiO{sub 2} core/RuO{sub 2} shell submicron-particles were prepared via a sequential spray pyrolysis. • Spherical particles have the mean particle diameters between 200 and 400 nm. • This method is promising for synthesis of core–shell and core–multishell materials. - Abstract: Spherical submicron-particles with TiO{sub 2} core–RuO{sub 2} shell structure have been synthesized by employing sequential ultrasonic spray pyrolysis. The particles have been investigated by X-ray powder diffraction, scanning electron microscopy and different transmission electron microscopy techniques. The quality of the core–shell structure of the particles has been confirmed by comparison of the experimental data with those generated on the basis of a hard sphere core–shell model. It has been found that the mixing of the Ru-containing aerosol with the TiO{sub 2} particle stream has a significant impact on the core–shell formation. The method introduced in this study can probably be applied for preparation of core–shell and core–multishell materials that are difficult to synthesize in a single step spray pyrolysis process.

  1. Influence of the process parameters on the spray pyrolysis technique, on the synthesis of gadolinium doped-ceria thin film

    SciTech Connect

    Halmenschlager, C.M.; Neagu, R.; Rose, L.; Department of Materials Engineering, V6T 1Z1 Vancouver, BC ; Malfatti, C.F.

    2013-02-15

    Graphical abstract: Gas-tight CGO made by spray pyrolysis suitable to be used as SOFC electrolyte. Display Omitted Highlights: ? Dense and crystalline CGO films deposited by spray pyrolysis on various substrates. ? Solvent did not have a strong influence on the film microstructure, defect concentration or thickness. ? The substrate did not have a strong influence on the film microstructure, defect concentration or thickness. ? Films with at least 2.5 ?m of thickness presented high impermeability. ? The films obtained are suitable to use as a SOFC electrolyte. -- Abstract: This work presents the results of a process of optimization applied to gadolinia-doped ceria (Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9?x}, or CGO) thin films, deposited by spray pyrolysis (SP). Spray pyrolysis is a high thermal deposition method that combines material deposition and heat treatment. This combination is advantageous since the post-deposition heat treatment step is not necessary. However, stresses are solidified in the coating during the deposition, which may lead to the initiation of a crack in the coating. The aim of this work was to achieve thin, dense, and continuous CGO coatings, which may be used as gas separation membranes and as a solid state electrochemical interfaces. Dense, flat, low-defect substrates such as silica slides, silicon mono crystal wafers, and porous substrates were used as substrates in this work. Cerium ammonium nitrate and gadolinium acetylacetonate were dissolved in ethanol and butyl carbitol to form a precursor solution that was sprayed on the heated substrates. Process parameters such as solvent composition, deposition rate and different heating regimes were analyzed. The microstructure was analyzed by secondary electron microscopy (SEM) and was found that thin, dense, and defect-free films could be produced on dense and porous substrates. The results obtained show that it is possible to obtain a CGO dense film deposited by spray pyrolysis. X-ray diffraction (XRD) analysis showed that the films were crystalline after the deposition without requiring post-deposition heat treatment. The crystallite size does not vary significantly as a function of the annealing temperature.

  2. Resistance to Corrosion of Zirconia Coatings Deposited by Spray Pyrolysis in Nitrided Steel

    NASA Astrophysics Data System (ADS)

    Cubillos, G. I.; Olaya, J. J.; Bethencourt, M.; Cifredo, G.; Blanco, G.

    2013-10-01

    Coatings of zirconium oxide were deposited onto three types of stainless steel, AISI 316L, 2205, and tool steel AISI D2, using the ultrasonic spray pyrolysis method. The effect of the flux ratio on the process and its influence on the structure and morphology of the coatings were investigated. The coatings obtained, 600 nm thick, were characterized using x-ray diffraction, scanning electron microscopy, confocal microscopy, and atomic force microscopy. The resistance to corrosion of the coatings deposited over steel (not nitrided) and stainless steel nitrided (for 2 h at 823 K) in an ammonia atmosphere was evaluated. The zirconia coating enhances the stainless steel's resistance to corrosion, with the greatest increase in corrosion resistance being observed for tool steel. When the deposition is performed on previously nitrided stainless steel, the morphology of the surface improves and the coating is more homogeneous, which leads to an improved corrosion resistance.

  3. Nanostructure and magnetic properties of magnesium ferrite thin films deposited on glass substrate by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Arabi, H.; Khalili Moghadam, N.

    2013-06-01

    The spinel MgFe2O4 thin films were prepared on the glass substrates at TS=400 C by the spray pyrolysis deposition method. Structural and magnetic properties of the calcinated thin films at different temperatures were also investigated. By changing the calcination temperature from 400 to 600 C, the crystallite size increased from 10 to 15 nm and the crystallinity of the films improved slightly. Thickness of the films calcinated at 400 and 600 C were 0.648 and 1.473 ?m respectively. However, the surface morphology of the films did not change considerably. Magnetic measurements, when the applied magnetic field was in parallel and perpendicular directions, showed the isotropic magnetic nature of the prepared films and their magnetic properties increased with the increment of calcination temperature. The Hc value of thin films calcinated at 400 C was about 168 Oe.

  4. Structural, optical and electrical properties of zinc oxide thin films deposited by a spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Aoun, Yacine; Benhaoua, Boubaker; Gasmi, Brahim; Benramache, Said

    2015-01-01

    Zinc oxide (ZnO) thin films were deposited on glass substrates by spray pyrolysis technique decomposition of zinc acetate dihydrate in an ethanol solution with 30 mL of deposition rate, the ZnO thin films were deposited at two different temperatures: 300 and 350 C. The substrates were heated using the solar cells method. The substrate was R217102 glass, whose size was 30 17.5 1 mm3. The films exhibit a hexagonal wurtzite structure with a strong (002) preferred orientation. The higher value of crystallite size is attained for sprayed films at 350 C, which is probably due to an improvement of the crystallinity of the films at this point. The average transmittance of obtain films is about 90%-95%, as measured by a UVvis analyzer. The band gap energy varies from 3.265 to 3.294 eV for the deposited ZnO thin film at 300 and 350 C, respectively. The electrical resistivity measured of our films are in the order 0.36 ?cm.

  5. Ultrasonic spray pyrolysis growth of ZnO and ZnO:Al nanostructured films: Application to photocatalysis

    SciTech Connect

    Kenanakis, G.; Katsarakis, N.

    2014-12-15

    Highlights: • Al–ZnO thin films and nanostructures were obtained by ultrasonic spray pyrolysis. • The texture and morphology of the samples depend on the deposition parameters. • The photocatalytic degradation of stearic acid was studied upon UV-A irradiation. - Abstract: Pure and Al-doped ZnO (Al = 1, 3, 5%) nanostructured thin films were grown at 400 °C on glass substrates by ultrasonic spray pyrolysis, a simple, environmental-friendly and inexpensive method, using aqueous solutions as precursors. The structural and morphological characteristics of the samples depend drastically on deposition parameters; ZnO nanostructured films, nanopetals and nanorods were systematically obtained by simply varying the precursor solution and/or the spraying time. Transmittance measurements have shown that all samples are transparent in the visible wavelength region. Finally, the photocatalytic properties of the samples were investigated against the degradation of stearic acid under UV-A light illumination (365 nm); both pure and Al-doped ZnO nanostructured thin films show good photocatalytic activity regarding the degradation of stearic acid, due to their good crystallinity and large surface area.

  6. Thin films of SiO2 and hydroxyapatite on titanium deposited by spray pyrolysis.

    PubMed

    Jokanovic, V; Jokanovic, B; Izvonar, D; Dacic, B

    2008-05-01

    Wet spray pyrolysis of fine, well-dispersed a SiO2 sol was used for the deposition of thin films of silicon dioxide. The sol was obtained by hydrothermal precipitation of silicon acid from a solution at pH = 10. The morphology, roughness, phase composition, chemical homogeneity and the mechanism of the films were investigated by SEM, EDS and IR spectroscopy. The obtained results show a complete covering of the titanium substrate with SiO2 after 3 h of deposition. It was observed that the film thickness increased from 3 to 19 microm, the roughness of the film decreased from 12 to 3 microm, while the morphology of the deposit changed considerably. A hydroxyapatite film was prepared on the so-obtained SiO2 thin film by spray pyrolysis deposition and its morphology and phase composition were investigated. PMID:17914612

  7. Preparation and photovoltaic properties of tin sulfide and tin oxysulfide thin films by spray pyrolysis technique

    SciTech Connect

    Kosugi, Tsuyoshi; Murakami, Kenji; Kaneko, Shoji

    1998-12-31

    Tin sulfide and a related novel compound, tin oxysulfide, thin films were deposited from the aqueous solution containing tin (II) chloride and thiourea by a spray pyrolysis technique. The constituent atoms of the thin films have merits of nontoxicity and availability. Physical and photovoltaic properties of both films were also investigated. It has, therefore, been considered that these two compounds become a promising absorbing layer for solar cell on account photovoltaic ability with high absorption coefficient and appropriate bandgap energy.

  8. Phase transition studies in bismuth ferrite thin films synthesized via spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Goyal, Ankit; Lakhotia, Harish

    2013-06-01

    Multiferroic are the materials, which combine two or more "ferroic" properties, ferromagnetism, ferroelectricity or ferroelasticity. BiFeO3 is the only single phase multiferroic material which possesses a high Curie temperature (TC 1103 K), and a high Neel temperature (TN 643 K) at room temperature. Normally sophisticated methods are being used to deposit thin films but here we have tried a different method Low cost Spray Pyrolysis Method to deposit BiFeO3 thin film of Glass Substrate with rhombohedral crystal structure and R3c space group. Bismuth Ferrite thin films are synthesized using Bismuth Nitrate and Iron Nitrate as precursor solutions. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to study structural analysis of prepared thin films. XRD pattern shows phase formation of BiFeO3 and SEM analysis shows formation of nanocrystals of 200 nm. High Temperature Resistivity measurements were done by using Keithley Electrometer (Two Probe system). Abrupt behavior in temperature range (313 K - 400K) has been observed in resistance studies which more likely suggests that in this transition the structure is tetragonal rather than rhombohedral. BiFeO3 is the potential active material in the next generation of ferroelectric memory devices.

  9. Corrosion resistance of zirconium oxynitride coatings deposited via DC unbalanced magnetron sputtering and spray pyrolysis-nitriding

    NASA Astrophysics Data System (ADS)

    Cubillos, G. I.; Bethencourt, M.; Olaya, J. J.

    2015-02-01

    ZrOxNy/ZrO2 thin films were deposited on stainless steel using two different methods: ultrasonic spray pyrolysis-nitriding (SPY-N) and the DC unbalanced magnetron sputtering technique (UBMS). Using the first method, ZrO2 was initially deposited and subsequently nitrided in an anhydrous ammonia atmosphere at 1023 K at atmospheric pressure. For UBMS, the film was deposited in an atmosphere of air/argon with a Φair/ΦAr flow ratio of 3.0. Structural analysis was carried out through X-ray diffraction (XRD), and morphological analysis was done through scanning electron microscopy (SEM) and atomic force microscopy (AFM). Chemical analysis was carried out using X-ray photoelectron spectroscopy (XPS). ZrOxNy rhombohedral polycrystalline film was produced with spray pyrolysis-nitriding, whereas using the UBMS technique, the oxynitride films grew with cubic Zr2ON2 crystalline structures preferentially oriented along the (2 2 2) plane. Upon chemical analysis of the surface, the coatings exhibited spectral lines of Zr3d, O1s, and N1s, characteristic of zirconium oxynitride/zirconia. SEM analysis showed the homogeneity of the films, and AFM showed morphological differences according to the deposition technique of the coatings. Zirconium oxynitride films enhanced the stainless steel's resistance to corrosion using both techniques. The protective efficacy was evaluated using electrochemical techniques based on linear polarization (LP). The results indicated that the layers provide good resistance to corrosion when exposed to chloride-containing media.

  10. Emission of ZnO:Ag nanorods obtained by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Velzquez Lozada, E.; Torchynska, T. V.; Casas Espinola, J. L.; Prez Millan, B.

    2014-11-01

    Scanning electronic microscopy (SEM), X ray diffraction (XRD), photoluminescence (PL) and its temperature dependence have been studied in ZnO:Ag nanorods (NRs) prepared by the ultrasonic spray pyrolysis (USP) method. The time variation at the growth of ZnO:Ag films permits modifying the ZnO phase from the amorphous to crystalline, to change the size of ZnO:Ag NRs and to vary their emission spectra. PL spectra of ZnO:Ag NRs versus temperature has been investigated. This study reveals that the PL band related to the acceptor AgZn (LO phonon replicas of an acceptor bound exciton, ABE (2.877 eV)), and its second-order diffraction peak (1.44 eV) disappeared in the temperature range of 10-170 K with the formation of free exciton (FX). The PL intensity of defect related PL bands decreases monotonously in the range 10-300 K with the activation energy of 13 meV. The PL band (3.22 eV), related to the LO phonon replica of free exciton (FX-2LO) and its second-order diffraction peak (1.61 eV) increase monotonously in the range 10-300 K. FX related peak dominates in PL spectra at room temperature that testifies on the high quality of ZnO:Ag films prepared by the USP technology.

  11. Electrical and optical properties of Al doped Zno film prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Shrestha, Shankar Prasad; Basnet, Pradeep

    2008-04-01

    Transparent conducting thin films of zinc oxides and aluminum doped zinc oxide (AZO) were prepared by the spray pyrolysis technique using an aqueous solution of dehydrate zinc acetate (CH 3COOH. 2H IIO, pure- Merck A. R. grade) and hex hydrate aluminum chloride (AlCl 3 .6H IIO) on the micro glass slides. The prepared thin films are found to be highly adherent to the substrate and possess uniform conduction. The optical and electrical properties of the film were investigated in terms of different Al concentration in the starting solution and different substrate temperature. Four probe method in Van der pauw configuration was used for electrical resistivity measurements. The resistivity of Al doped film is observed to vary with doping concentration. The lowest resistivity is observed in the film doping with 2 at % [Al/Zn]. The Hall coefficient measurements show that both ZnO and AZO show the n-type conduction. The carrier concentration was observed to be highest at 2 at% of Al doping. The optical measurements of all the samples with aluminum concentrations was found to be >85 % showing the film to be highly transparent in nature. With increase in Al concentration, the optical band gap was observed increase from 3.27 eV to 3.41 eV.

  12. Conductivity study of nitrogen-doped calcium zinc oxide prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Ting; Lan, Wen-How; Huang, Kai-Feng; Lin, Jia-Ching; Chang, Kuo-Jen

    2016-01-01

    In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm2 V-1 s-1 and 2.8×1017 cm-3, respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274-0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

  13. ZnO based visible-blind UV photodetector by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Inamdar, S. I.; Ganbavle, V. V.; Rajpure, K. Y.

    2014-12-01

    Zinc oxide (ZnO) metal-semiconductor-metal ultraviolet photodetectors were fabricated by economical spray pyrolysis method. The devices have been characterized to investigate the effect of precursor solution concentration on the photoconductive properties of ZnO. The structural, morphological and optical properties of the ZnO thin films were studied using different techniques. The crystal structure, size and lattice parameters have been estimated by X-ray diffraction (XRD) analysis. The UV photodetector device prepared using 0.1 M solution concentration exhibits low dark current and high UV photocurrent of about 134 μA at 5 V bias at 365 nm peak wavelength. The surface morphology and the surface roughness have been studied by AFM analysis. UV-Vis measurements have been used to study the effect of solution concentration on absorption spectra and hence on the band gap. The present device shows fast response in UV region of electromagnetic spectrum and shows almost no response to visible light. The characteristic times for rise and fall of the photocurrent device were 12 s and 9 s respectively. This devices are providing a simple and economical way to fabricate high-performance 'visible-blind' UV detectors and promising for use in large-area UV-A photodetector applications.

  14. Yolk-shelled cathode materials with extremely high electrochemical performances prepared by spray pyrolysis.

    PubMed

    Choi, Seung Ho; Hong, Young Jun; Kang, Yun Chan

    2013-09-01

    A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000(th) high discharge capacity of 108 mA h g(-1) at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g(-1) at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg(-1). The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles. PMID:23846530

  15. Ultrasonic spray pyrolysis deposition of SnSe and SnSe2 using a single spray solution

    NASA Astrophysics Data System (ADS)

    Narro-Rios, Jorge Sergio; Ramachandran, Manoj; Martnez-Escobar, Dalia; Snchez-Jurez, Aarn

    2013-01-01

    Thin films of SnSe and SnSe2 have been deposited using the ultrasonic spray pyrolysis (USP) technique. To the best of our knowledge this is the first report of the deposition of SnSe and SnSe2 thin films using a single spray solution. The use of a single spray solution for obtaining both a p-type material, SnSe, and an n-type material, SnSe2, simplifies the deposition technique. The SnSe2 thin films have a bandgap of 1.1 eV and the SnSe thin films have a band gap of 0.9 eV. The Hall measurements were used to determine the resistivity of the thin films. The SnSe2 thin films show a resistivity of 36.73 ?cm and n-type conductivity while the SnSe thin films show a resistivity of 180 ?cm and p-type conductivity.

  16. Structural and optical characterization of InAs nanocrystals deposited by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Mousa, A. M.; Mohammed, M. A.; Kadhim, R.

    2015-03-01

    4-5 nm size InAs nanocrystals were prepared by spray pyrolysis technique on glass substrates from alkaline solution containing InCl3 and As2O. X-Ray diffraction and absorption spectra suggested that the deposition conditions (deposition time and temperature) had a profound influence on the structure and thickness of deposited layers. The optical absorption band edges shifted to lower energy when increasing the thickness with respect to the bulk material. The marked blue shift of the optical absorption edge indicated a strong quantum confinement effect in InAs films.

  17. Study of photoconductivity in Ni doped CdS thin films prepared by spray pyrolysis technique

    SciTech Connect

    Patidar, Manju Mishra Gangrade, Mohan; Nath, R.; Ganesan, V.; Ajay, Akhil; Wala, Arwa Dewas; N, Kiran; Panda, Richa

    2014-04-24

    Ni-doped cadmium sulphide [Cd{sub 1−x}Ni{sub x}S, (x=0, 0.03, 0.05 and 0.20)] thin films were investigated for photoconductive properties. The films were prepared by spray Pyrolysis technique (SPT). AFM and two probe resistivity measurements were carried out to analyze the morphological and electrical properties of the films. AFM shows the note worthy changes in the morphology where the nanorod structures in CdS is changed into nano particles with the Ni doping. The presence of persistence photo current is demonstrated and extensive photoconductivity analysis has been studied on these films.

  18. Thin Film CuInS2 Prepared by Spray Pyrolysis with Single-Source Precursors

    NASA Technical Reports Server (NTRS)

    Jin, Michael H.; Banger, Kulinder K.; Harris, Jerry D.; Cowen, Jonathan E.; Hepp, Aloysius F.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Both horizontal hot-wall and vertical cold-wall atmospheric chemical spray pyrolysis processes deposited near single-phase stoichiometric CuInS2 thin films. Single-source precursors developed for ternary chalcopyrite materials were used for this study, and a new liquid phase single-source precursor was tested with a vertical cold-wall reactor. The depositions were carried out under an argon atmosphere, and the substrate temperature was kept at 400 C. Columnar grain structure was obtained with vapor deposition, and the granular structure was obtained with (liquid) droplet deposition. Conductive films were deposited with planar electrical resistivities ranging from 1 to 30 Omega x cm.

  19. Semiconducting properties of Tm doped Yb-ZnO films by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Chaki, Imane; Belayachi, Azzam; El Bahraoui, Toufik; Regragui, Mohamed; Abd-Lefdil, Mohamed

    2014-12-01

    In this work, we have investigated the structural, optical and electrical properties of rare earth co-doped zinc oxide thin films prepared by spray pyrolysis technique. X-ray diffraction has shown that the films are polycrystalline and textured with the c-axis of the wurtzite structure along the growth direction. Scanning electronic microscopy and transmission electronic microscopy were used to study the films composition and morphology. Photoluminescence measurements showed that all the films have a strong emission band at around 380 nm. Layers with electrical resistivity values as low as 5.7 × 10-2 Ω cm were obtained.

  20. Zinc Oxide Thin-Film Transistors Fabricated at Low Temperature by Chemical Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Jeong, Yesul; Pearson, Christopher; Lee, Yong Uk; Winchester, Lee; Hwang, Jaeeun; Kim, Hongdoo; Do, Lee-Mi; Petty, Michael C.

    2014-11-01

    We report the electrical behavior of undoped zinc oxide thin-film transistors (TFTs) fabricated by low-temperature chemical spray pyrolysis. An aerosol system utilizing aerodynamic focusing was used to deposit the ZnO. Polycrystalline films were subsequently formed by annealing at the relatively low temperature of 140°C. The saturation mobility of the TFTs was 2 cm2/Vs, which is the highest reported for undoped ZnO TFTs manufactured below 150°C. The devices also had an on/off ratio of 104 and a threshold voltage of -3.5 V. These values were found to depend reversibly on measurement conditions.

  1. Growth of ?-In2Se3 Thin Films by Electrostatic Spray Pyrolysis Deposition

    NASA Astrophysics Data System (ADS)

    Kato, Takamasa; Hiramatsu, Toshitaka; Onojima, Norio

    2011-05-01

    ?-In2Se3 thin films were grown by the electrostatic spray pyrolysis deposition growth technique. We investigated the dependence of the crystalline quality and optical properties of the grown films on the growth conditions, such as growth temperatures and the molar ratios of source material Se/In in the precursor solution. The films which were highly aligned to the c-axis were grown at low growth temperature of 250 C on glass substrates. The optical band gap energy was about 1.94 eV and was independent of the growth temperatures and the molar ratios Se/In in the precursor solution.

  2. MgB 2 powder preparation through a spray pyrolysis process

    NASA Astrophysics Data System (ADS)

    Ko, Jae-Woong; Yoo, Jaimoo; Kim, Young-Kuk; Chung, Kook Chae; Yoo, Sang-Im; Wang, Xiao Lin; Dou, Shi Xue

    2006-10-01

    Nano-sized spherical MgB2 powders have been successfully synthesized by spray pyrolysis to improve the flux pinning property and to increase Hc2. The microstructure and average particle size were influenced by solution concentration, furnace temperature and mass flow of carrier gas. The particle size was decreased and became more uniform with decreasing solute concentration in the solution. For adequate preparation conditions, it has mostly spherical, solid and narrow particle size distribution. Average particle size (X50) distribution was between 100 and 400 nm. The critical temperature for the synthesized MgB2 powder was around 36 K.

  3. Structural and optical characterization of InAs nanocrystals deposited by spray pyrolysis

    SciTech Connect

    Mousa, A. M. Mohammed, M. A.; Kadhim, R.

    2015-03-30

    4-5 nm size InAs nanocrystals were prepared by spray pyrolysis technique on glass substrates from alkaline solution containing InCl{sub 3} and As{sub 2}O. X-Ray diffraction and absorption spectra suggested that the deposition conditions (deposition time and temperature) had a profound influence on the structure and thickness of deposited layers. The optical absorption band edges shifted to lower energy when increasing the thickness with respect to the bulk material. The marked blue shift of the optical absorption edge indicated a strong quantum confinement effect in InAs films.

  4. Low-defect CeO2 films synthesis by combined spray pyrolysis using different precursors

    NASA Astrophysics Data System (ADS)

    Silva, T. G.; Ferreira, A. L.; Ribeiro, E.; Silveira, E.; Mattoso, N.

    2015-03-01

    films were fabricated by combining both a modified spray pyrolysis and the vapour transport deposition techniques. Two different precursors, cerium chloride and cerium acetate, were explored. In our approach, the pyrolytic process was not concomitant with the spray deposition and the introduction of the vapour transport condition has showed to improve both the morphological and optical quality of the films. Samples obtained from cerium chloride show a porous morphology, usual for polycrystalline layers, and a homogeneous light emission. When using vapour transport during thermal treatment, we achieved an enhanced luminescence, blue shifted to 3.08 eV and with negligible presence of defect bands. Films obtained from cerium acetate present similar crystalline properties, and a more defined light emission line shape, also peaked at 3.08 eV but with even lower contribution from known green-red defect bands. These results show that the proposed combined technique leads to films with homogeneous, enhanced optical properties.

  5. Uniform nanoparticles by flame-assisted spray pyrolysis (FASP) of low cost precursors

    PubMed Central

    Rudin, Thomas; Wegner, Karsten

    2013-01-01

    A new flame-assisted spray pyrolysis (FASP) reactor design is presented, which allows the use of inexpensive precursors and solvents (e.g., ethanol) for synthesis of nanoparticles (1020 nm) with uniform characteristics. In this reactor design, a gas-assisted atomizer generates the precursor solution spray that is mixed and combusted with externally fed inexpensive fuel gases (acetylene or methane) at a defined height above the atomizing nozzle. The gaseous fuel feed can be varied to control the combustion enthalpy content of the flame and onset of particle formation. This way, the enthalpy density of the flame is decoupled from the precursor solution composition. Low enthalpy content precursor solutions are prone to synthesis of non-uniform particles (e.g., bimodal particle size distribution) by standard flame spray pyrolysis (FSP) processes. For example, metal nitrates in ethanol typically produce nanosized particles by gas-to-particle conversion along with larger particles by droplet-to-particle conversion. The present FASP design facilitates the use of such low enthalpy precursor solutions for synthesis of homogeneous nanopowders by increasing the combustion enthalpy density of the flame with low-cost, gaseous fuels. The effect of flame enthalpy density on product properties in the FASP configuration is explored by the example of Bi2O3 nanoparticles produced from bismuth nitrate in ethanol. Product powders were characterized by nitrogen adsorption, X-ray diffraction, X-ray disk centrifuge, and transmission electron microscopy. Homogeneous Bi2O3 nanopowders were produced both by increasing the gaseous fuel content and, most notably, by cutting the air entrainment prior to ignition of the spray. PMID:23408113

  6. Characterisation of samarium and nitrogen co-doped TiO2 films prepared by chemical spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Oja Acik, I.; Kiisk, V.; Krunks, M.; Sildos, I.; Junolainen, A.; Danilson, M.; Mere, A.; Mikli, V.

    2012-11-01

    The sol-gel chemical spray pyrolysis method was used to deposit samarium and nitrogen co-doped TiO2 films onto a quartz substrate at a growth temperature of 450 C using pulsed spray solution feed, followed by annealing at 500 C for 2 h in air. The obtained films exhibited anatase structure independent of the doping level. According to XRD analysis, the mean crystallite size of the undoped TiO2, TiO2:N(25) and TiO2:N(5):Sm(5) films was 32, 38 and 20 nm, respectively. According to AFM, the undoped TiO2 film consisted of agglomerates with a size of 30-200 nm. N-doping (25 at%) transformed the agglomerates into individually distinctive grains with a size of ca. 30 nm, while Sm doping (5 at%) caused a significant decrease in the average diameter of the agglomerates to ca. 100 nm. The RMS roughness of the undoped TiO2 film was 1.7 nm; doping resulted in the formation of smoother films with RMS roughness of 0.9-1.4 nm. XPS data indicated that the Sm and N dopants were incorporated into the TiO2 crystal lattice and/or adsorbed on the surface of the film. An increasing nitrogen concentration in the spray solution correlates to a systematic suppressing of the photoluminescence intensity of Sm3+.

  7. Boron doped nanostructure ZnO films deposited by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Karakaya, Seniye; Ozbas, Omer

    2015-02-01

    ZnO is an II-VI compound semiconductor with a wide direct band gap of 3.3 eV at room temperature. Doped with group III elements (B, Al or Ga), it becomes an attractive candidate to replace tin oxide (SnO2) or indium tin oxide (ITO) as transparent conducting electrodes in solar cell devices and flat panel display due to competitive electrical and optical properties. In this work, ZnO and boron doped ZnO (ZnO:B) films have been deposited onto glass substrates at 350 ± 5 °C by a cost-efficient ultrasonic spray pyrolysis technique. The optical, structural, morphological and electrical properties of nanostructure undoped and ZnO:B films have been investigated. Electrical resistivity of films has been analyzed by four-probe technique. Optical properties and thicknesses of the films have been examined in the wavelength range 1200-1600 nm by using spectroscopic ellipsometry (SE) measurements. The optical constants (refractive index (n) and extinction coefficient (k)) and the thicknesses of the films have been fitted according to Cauchy model. The optical method has been used to determine the band gap value of the films. Transmission spectra have been taken by UV spectrophotometer. It is found that both ZnO and ZnO:B films have high average optical transmission (≥80%). X-ray diffraction (XRD) patterns indicate that the obtained ZnO has a hexagonal wurtzite type structure. The morphological properties of the films were studied by atomic force microscopy (AFM). The surface morphology of the nanostructure films is found to depend on the concentration of B. As a result, ZnO:B films are promising contender for their potential use as transparent window layer and electrodes in solar cells.

  8. Analysis of carrier gas flow rate effect on hydroxyapatite particle formation in ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Widiyastuti, W.; Setiawan, Adhi; Nurtono, Tantular; Winardi, Sugeng

    2016-02-01

    Ultrasonic spray pyrolysis has been well-known process for producing fine particles from single and multicomponent materials. Here, the effect of carrier gas flow rate in ultrasonic spray pyrolysis process was studied in the particle formation of hydroxyapatite using solution precursor of Ca(CH3COO)2 and (NH4)2HPO4 with Ca/P ratio of 1.67. The experimental analysis was accompanied with computational fluid dynamics (CFD) simulation for comparison. In the simulation, the evaporation of the solvent in the droplets, a second evaporation due to crust formation, the decomposition reaction of the precursor involving the transfer of heat and mass transfer from droplet to surrounding were considered. By maintaining temperature at 900 °C, the residence time increased with decreasing the carrier gas flow rate led to the increasing the evaporation rate and the reacted fraction of the precursor. The predicted and experimental results of average particles size were agreed well with discrepancy 6.3%.

  9. Electrochemical properties of tungsten sulfidecarbon composite microspheres prepared by spray pyrolysis

    PubMed Central

    Choi, Seung Ho; Boo, Sung Jin; Lee, Jong-Heun; Kang, Yun Chan

    2014-01-01

    Tungsten sulfide (WS2)carbon composite powders with superior electrochemical properties are prepared by a two-step process. WO3-carbon composite powders were first prepared by conventional spray pyrolysis, and they were then sulfidated to form WS2-carbon powders. Bare WS2 powders are also prepared by sulfidation of bare WO3 powders obtained by spray pyrolysis. Stacked graphitic layers could not be found in the bare WS2 and WS2carbon composite powders. The amorphous bare WS2 and WS2carbon composite powders have BrunauerEmmettTeller (BET) surface areas of 2.8 and 4?m2 g?1, respectively. The initial discharge and charge capacities of the WS2carbon composite powders at a current density of 100?mA g?1 are 1055 and 714?mA h g?1, respectively, and the corresponding initial Coulombic efficiency is 68%. On the other hand, the initial discharge and charge capacities of the bare WS2 powders are 514 and 346?mA h g?1, respectively. The discharge capacities of the WS2carbon composite powders for the 2nd and 50th cycles are 716 and 555?mA h g?1, respectively, and the corresponding capacity retention measured after first cycle is 78%. PMID:25169439

  10. Electrochemical properties of tungsten sulfide-carbon composite microspheres prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Choi, Seung Ho; Boo, Sung Jin; Lee, Jong-Heun; Kang, Yun Chan

    2014-08-01

    Tungsten sulfide (WS2)-carbon composite powders with superior electrochemical properties are prepared by a two-step process. WO3-carbon composite powders were first prepared by conventional spray pyrolysis, and they were then sulfidated to form WS2-carbon powders. Bare WS2 powders are also prepared by sulfidation of bare WO3 powders obtained by spray pyrolysis. Stacked graphitic layers could not be found in the bare WS2 and WS2-carbon composite powders. The amorphous bare WS2 and WS2-carbon composite powders have Brunauer-Emmett-Teller (BET) surface areas of 2.8 and 4 m2 g-1, respectively. The initial discharge and charge capacities of the WS2-carbon composite powders at a current density of 100 mA g-1 are 1055 and 714 mA h g-1, respectively, and the corresponding initial Coulombic efficiency is 68%. On the other hand, the initial discharge and charge capacities of the bare WS2 powders are 514 and 346 mA h g-1, respectively. The discharge capacities of the WS2-carbon composite powders for the 2nd and 50th cycles are 716 and 555 mA h g-1, respectively, and the corresponding capacity retention measured after first cycle is 78%.

  11. Surfactant-assisted ultrasonic spray pyrolysis of nickel oxide and lithium-doped nickel oxide thin films, toward electrochromic applications

    NASA Astrophysics Data System (ADS)

    Denayer, Jessica; Bister, Geoffroy; Simonis, Priscilla; Colson, Pierre; Maho, Anthony; Aubry, Philippe; Vertruyen, Bndicte; Henrist, Catherine; Lardot, Vronique; Cambier, Francis; Cloots, Rudi

    2014-12-01

    Lithium-doped nickel oxide and undoped nickel oxide thin films have been deposited on FTO/glass substrates by a surfactant-assisted ultrasonic spray pyrolysis. The addition of polyethylene glycol in the sprayed solution has led to improved uniformity and reduced light scattering compared to films made without surfactant. Furthermore, the presence of lithium ions in NiO films has resulted in improved electrochromic performances (coloration contrast and efficiency), but with a slight decrease of the electrochromic switching kinetics.

  12. Yolk-shelled cathode materials with extremely high electrochemical performances prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Choi, Seung Ho; Hong, Young Jun; Kang, Yun Chan

    2013-08-01

    A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 mA h g-1 at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g-1 at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg-1. The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles.A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 mA h g-1 at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g-1 at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg-1. The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01675g

  13. Methods for deoxygenating biomass-derived pyrolysis oil

    SciTech Connect

    Brandvold, Timothy A.

    2015-07-14

    Methods for deoxygenating a biomass-derived pyrolysis oil are provided. A method comprising the steps of diluting the biomass-derived pyrolysis oil with a phenolic-containing diluent to form a diluted pyoil-phenolic feed is provided. The diluted pyoil-phenolic feed is contacted with a deoxygenating catalyst in the presence of hydrogen at hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent.

  14. Structural, optical and electrical properties of transparent conducting hydrophobic cadmium oxide thin films prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Sankarasubramanian, K.; Soundarrajan, P.; Sethuraman, K.; Ramesh Babu, R.; Ramamurthi, K.

    2014-05-01

    Cadmium oxide thin films were deposited by spray pyrolysis method on the glass substrate at 300 °C using different concentration of cadmium acetate. X-ray diffraction (XRD) measurements show that the coated CdO film belongs to cubic crystal structure with preferential orientation along (1 1 1) direction. Wettability results revealed that the hydrophobic character of CdO thin film is enhanced with increase in the precursor concentrations. The surface morphology and roughness of the films were determined by Atomic Force Microscope (AFM). The average optical transmittance of CdO films in the range 400-800 nm, is about 80%. The resistivity, mobility and carrier concentration of CdO thin films were determined by Hall effect measurement. Photoluminescence (PL) spectra showed a strong emission peak around 590 nm.

  15. Synthesis and characterization of nickel oxide thin films deposited on glass substrates using spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Jlassi, M.; Sta, I.; Hajji, M.; Ezzaouia, H.

    2014-07-01

    A simple and inexpensive spray pyrolysis technique was employed to deposit nickel oxide (NiO) thin films from hydrated nickel chloride salt solution onto amorphous glass substrate. The as-deposited films were transparent, uniform and well adherent to the glass substrate. The effect of the substrate temperature, the volume and the concentration of the sprayed solution on the structural, optical and electrical properties was studied using X-ray diffraction, optical transmittance, four point probe, scanning electron microscopy and atomic force microscopy. The structural analyses show that all the samples have a cubic structure. It was found that the increase in the volume of sprayed solution leads to an increment in the crystallite size of NiO and improves the homogeneity of the film. Optical measurements have shown that an increase in the thickness of the layer results in a decrease in the optical transmission, but it remains higher than 70% even if the thickness exceeds 600 nm. At the same time, the optical gap decreases from 3.7 to 3.55 eV when the thickness increases from 133 to 620 nm. Low values of the electrical resistivity (less than 10 ? cm) were obtained for thin films with thicknesses less than about 240 nm, but for higher thicknesses the resistivity increases linearly to reach about 170 ? cm for a thickness of 620 nm.

  16. Low-cost plasmonic solar cells prepared by chemical spray pyrolysis

    PubMed Central

    Katerski, Atanas; Oja Acik, Ilona; Mikli, Valdek; Mere, Arvo; Sildos, Ilmo; Krunks, Malle

    2014-01-01

    Summary Solar cells consisting of an extremely thin In2S3/CuInS2 buffer/absorber layer uniformly covering planar ZnO were prepared entirely by chemical spray pyrolysis. Au nanoparticles (Au-NPs) were formed via thermal decomposition of a gold(III) chloride trihydrate (HAuCl43H2O) precursor by spraying 2 mmol/L of the aqueous precursor solution onto a substrate held at 260 C. Currentvoltage scans and external quantum efficiency spectra were used to evaluate the solar cell performance. This work investigates the effect of the location of the Au-NP layer deposition (front side vs rear side) in the solar cell and the effect of varying the volume (2.510 mL) of the sprayed Au precursor solution. A 63% increase (from 4.6 to 7.5 mA/cm2) of the short-circuit current density was observed when 2.5 mL of the precursor solution was deposited onto the rear side of the solar cell. PMID:25551068

  17. Properties of NiO thin films deposited by intermittent spray pyrolysis process

    NASA Astrophysics Data System (ADS)

    Reguig, B. A.; Khelil, A.; Cattin, L.; Morsli, M.; Bernède, J. C.

    2007-02-01

    NiO thin films have been grown on glass substrates by intermittent spray pyrolysis deposition of NiCl 2·6H 2O diluted in distilled water, using a simple "perfume atomizer". The effect of the solution molarity on their properties was studied and compared to those of NiO thin films deposited with a classical spray system. It is shown that NiO thin films crystallized in the NiO structure are achieved after deposition. Whatever the precursor molarity, the grain size is around 25-30 nm. The crystallites are preferentially oriented along the (1 1 1) direction. All the films are p-type. However, the thickness and the conductivity of the NiO films depend on the precursor contraction. By comparison with the properties of films deposited by classical spray technique, it is shown that the critical precursor concentration, which induces strong thin films properties perturbations, is higher when a perfume atomizer is used. This broader stability domain can be attributed to better chlorides decomposition during the rest time used in the perfume atomizer technique.

  18. Formation of CuAlO2 Film by Ultrasonic Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Iping, S.; Lockman, Zainovia; Hutagalung, S. D.; Kamsul, A.; Matsuda, Atsunori

    2011-10-01

    Smooth, crack free and homogenous CuAlO2 film was produced by chemical solution deposition process via spray pyrolysis technique on a cleaned Si substrate. The precursor solution used was comprised of a mixture of 45.87 mmol Cu(NO3)2.3H2O and 90 mmol Al(NO3)3.9H2O at ratio of Cu:Al = 1.2:1. The precursor solution was placed in a mist chamber and was atomized by a nebulizer to produce precursor mist. The precursor mist was then carried out by Ar gas and was sprayed onto a heated Si. Two main parameters were studied: the distance between the nozzle of the precursor mist chamber and the Si and the temperature of the Si substrate. It appears that from the XRD data, CuAlO2 can be detected for samples prepared by spraying the precursor mist at temperature of > 550 C with distance between the nozzle and the substrate of 3cm. Reaction of the Cu and Al ions in the mist near the substrate may have promoted the crystallisation of CuAlO2.

  19. Methods for deoxygenating biomass-derived pyrolysis oil

    DOEpatents

    Baird, Lance Awender; Brandvold, Timothy A.

    2015-06-30

    Methods for deoxygenating a biomass-derived pyrolysis oil are provided. A method for deoxygenating a biomass-derived pyrolysis oil comprising the steps of combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-pyoil diluent recycle stream to form a heated diluted pyoil feed stream is provided. The heated diluted pyoil feed stream has a feed temperature of about 150.degree. C. or greater. The heated diluted pyoil feed stream is contacted with a first deoxygenating catalyst in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent.

  20. Optoelectronic characteristics of YAG phosphor-incorporated ZnO films deposited by ultrasonic spray pyrolysis.

    PubMed

    Chen, Lung-Chien; Huang, Chien-Chung

    2012-01-01

    This work presents a novel white light device. An yttrium aluminum garnet (YAG) phosphor-incorporated zinc oxide (ZnO) film is deposited on a slide glass substrate by ultrasonic spray pyrolysis. A nanoflower consisting of a hexagonal nanopetal is formed on the surfaces of the samples, and the sizes of the nanopetal are approximately 200 to 700 nm. Additionally, the nanopetal becomes blunted with an increasing incorporated amount of YAG. As the incorporated amount is 1.5 and 2.5 wt.%, the photoluminescence color of the YAG-incorporated ZnO film is nearly white, possibly contributing to the YAG emission and the band-to-deep level transition in the ZnO film. PMID:23151219

  1. Field emission property of ZnO nanowires prepared by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Htay, Myo Than; Hashimoto, Yoshio

    2015-08-01

    The field emission property of cold cathode emitters utilizing the ZnO nanowires with various conditions prepared by ultrasonic spray pyrolysis technique was discussed. It is found that the emission current was enhanced in the emitters having higher aspect ratio as well as smaller sheet resistance. Applying of post-annealing process, utilization of additional Mo back electrode in the cathode, and coating of Mo on the ZnO nanowires resulted in the improvement of the emission current and lowering the threshold voltage. A threshold voltage of about 5.5 V/?m to obtain 1.0 ?A/cm2 was achieved in the sample prepared at the growth temperatures varying continuously from 250 C to 300 C.

  2. A study of copper films obtained from the nebulized spray pyrolysis of different precursors

    NASA Astrophysics Data System (ADS)

    Aiyer, Hemantkumar N.; Parashar, Sachin; Raju, A. R.; Shivashankar, S. A.; Rao, C. N. R.

    1999-01-01

    Metallic copper films have been deposited on Si(100) substrates by nebulized spray pyrolysis of Cu(acac)0022-3727/32/1/002/img7, Cu(hfac)0022-3727/32/1/002/img7 and Cu(dpm)0022-3727/32/1/002/img7. The structure and morphology of the films have been examined by x-ray diffraction and scanning electron microscopy. The films are polycrystalline in nature with a preferred (111) orientation. Based on the electrical resistivity data, various transport parameters of the films have been estimated. Growth kinetics and the environmental stability of the films from the precursors have been compared. Taking all the factors into account, Cu(dpm)0022-3727/32/1/002/img7 seems to yield the best films of copper metal.

  3. Semiconducting properties of aluminum-doped ZnO thin films grown by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Mahadik, M. A.; Hunge, Y. M.; Shinde, S. S.; Rajpure, K. Y.; Bhosale, C. H.

    2015-03-01

    Highly transparent and preferential c-axis oriented nanocrystalline undoped and Al doped zinc oxide (AZO) thin films have been deposited onto amorphous glass substrate by spray pyrolysis. The XRD studies reveal that AZO with a hexagonal (wurtzite) crystal structure having (002) preferred orientation is formed. The atomic force microscope (AFM) shows uniform surface topography. The optical band gap values of undoped and AZO thin films were changed from 3.34 to 3.35 eV. The band gap energy and photoluminescence are found to depend on the Al doping. Thermoelectric power measurement shows film having n-type in nature. Dielectric constant and loss (tan δ) were found to be frequency dependent. Interparticle interactions in the deposited films are studied by complex impendence spectroscopy.

  4. Hydrogen sensitivity performance of Pd doped SnO2 nanostructured film fabricated by spray pyrolysis.

    PubMed

    Wu, Xiaomeng; Ling, Yunhan; Zhi, Xin; Huang, Zhaohui

    2009-02-01

    The present investigation dealt with the fabrication of H2 gas sensor based on Pd doped SnO2. Porous SnO2 nanostructured film were fabricated by spray pyrolysis route using tin chloride pentahydrate (SnCl4.5H2O) solution as starting material, and PdCl2 as a dopant. Resistance measurements at different temperatures and concentration of H2 have been carried out with the samples. Microstructure and palladium dopant have been found to be critical factors determining the gas sensing properties of Pd/SnO2 specimens. The comparative gas sensitivity tests showed the excellent H2 sensing properties of the sensor in air was suggested to arise mainly from the improvement of gas absorption and catalytic effect of nano Pd dopant. PMID:19441376

  5. Transient photoconductivity properties of tungsten oxide thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hao, Jianhua; Studenikin, S. A.; Cocivera, Michael

    2001-11-01

    Tungsten oxide (WO3) thin films were deposited by spray pyrolysis of an ammonium tungsten oxide solution. The effect of postannealing on the structural, transport and optical properties of the films has been studied. Under steady-state illumination, slow photoconductivity growth and relaxation transients were observed at room temperature. The contributions of carrier concentration and mobility to the photoconductivity were determined from photo-Hall and photoconductivity data. The transient photoconductivity was found to be mainly due to photoinduced excess electrons over a wide time range from 0.0 to 104 s. This slow relaxation was characterized by two exponential decays indicating two discrete subband gap levels were involved. The fast photoconductivity relaxation over the time range from 10-8 to 10-1 s was more complicated and probably involved a distribution of subband gap states.

  6. Position-selective growth of ZnO nanowires by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Than Htay, Myo; Hashimoto, Yoshio; Momose, Noritaka; Ito, Kentaro

    2009-10-01

    Position-selective growth of ZnO nanowires was realized by utilizing a patterned soda-lime glass layer. The soda-lime glass layer contributes as the origin of nucleation sites for the growth of nanowires in economically viable ultrasonic spray pyrolysis technique. The formation of nanowires took place with good reproducibility at relatively low substrate temperatures of 250- 400C when the soda-lime glass matrix was present at the surface of substrates, and such a nitrate compound as nitric acid or nitrate salt was mixed in the precursor solutions. Based on this technique, the position-selective growth and density-controlled growth of ZnO nanowires can be performed on various types of substrate. The presence of a CaO compound in the glass matrix was revealed as an important condition to grow the nanowires.

  7. Fabrication of textured SnO 2:F thin films by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Ren, Yang; Zhao, Gaoyang; Chen, Yuanqing

    2011-11-01

    Transparent conductive SnO2:F thin films with textured surfaces were fabricated on soda-lime-silica glass substrates by spray pyrolysis. Structure, morphology, optical and electrical properties of the films were investigated. Results show that the film structure, morphology, haze, transmittance and sheet resistance are dependent on the substrate temperature and film thickness. An optimal 810 nm-thick SnO2:F film with textured surface deposited at 520 C exhibits polycrystalline rutile tetragonal structure with a (2 0 0) orientation. The sheet resistance, average transmittance in visible region, and haze of this film were 8 ?/?, 80.04% and 11.07%, respectively, which are suitable for the electrode used in the hydrogenated amorphous silicon solar cells.

  8. Carbon Nanotubes Using Palm Oil as Carbon Source in Spray Pyrolysis System

    NASA Astrophysics Data System (ADS)

    Azira, A. A.; Zainal, N. F. A.; Nik, S. F.; Rusop, M.

    2009-06-01

    Carbon nanotubes (CNTs) have been synthesized by catalytic decomposition of palm oil, on a silica powder support impregnated with Co, Ni and Co/Ni catalysts in the temperature range 500-900 C by the Spray Pyrolysis System. Co/Ni catalyst with 5 wt.% (molar ratio of Co:Ni = 1:1), impregnated in silica was found most suitable. Field Emission Scanning Electron Microscope (FESEM) reveals that the CNTs diameter ranging from 33-53 nm depending upon the conditions of deposition. The morphological studies support `tip growth mechanism' and `base growth mechanism' depending on the size of catalyst for the growth of the CNT's. FTIR results also presented in the paper.

  9. Ellipsometric Investigation of Optical Parameters and Characterization of Spray Pyrolysis-Derived ZnO Films

    NASA Astrophysics Data System (ADS)

    Geny?lmaz, Olcay; Atay, Ferhunde; Akyz, ?dris

    2015-09-01

    The pH value of solution is an important parameter in thin film production. In this work, ZnO films were successfully produced for various pH values (6.9 ? pH ? 3.2) by spray pyrolysis. The effects of the pH value on the optical parameters such as thickness, refractive index and extinction coefficient, structural, surface, and electrical properties were investigated by spectroscopic ellipsometry and other characterization technique. Thickness, refractive index, and extinction coefficient values were defined by spectroscopic ellipsometry technique using Cauchy-Urbach model. The thickness values of ZnO films were found to be in the range of 345 to 376 nm. The crystalline structure, orientation, and lattice parameters of the films were determined using XRD patterns. X-ray diffraction revealed that the crystallization level increased prominently with decreasing of the pH value and the best crystallization was found for pH 3.5 value. The average optical transmittance of the films was improved with changing of the pH values. Atomic force microscopic image was shown that the surface morphology improved and roughness value decreased with decrease of pH values. Electrical resistivity values of ZnO films decreased as the pH value decreased and the lowest resistivity value was found 1.1 10-3 ? cm for pH 3.5 deposited films. As a result, the low pH values have a strong effect on the mentioned properties of spray pyrolysis-derived ZnO films.

  10. Some physical properties of CdO:F thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Bagheri Khatibani, A.; Hallaj, Z. A.; Rozati, S. M.

    2015-12-01

    Different attractions of cadmium oxide in the field of materials science especially in semiconductor science and engineering encouraged us to study its physical properties. The preparation of a transparent conducting cadmium oxide doped with various concentration of fluorine (0%, 3%, 6%) in the spray solution on a glass substrate by spray pyrolysis is reported. The structural, morphological, electrical and optical properties were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Hall effect and UV-visible spectrophotometry. Different optical quantities such as optical band gap, refractive index, extinction coefficient, Urbach energy, oscillator energy, dispersion energy and nonlinear optical susceptibility were determined. The XRD, SEM, Hall effect and AFM showed the doping concentration effects on CdO thin-films properties. Observations such as the decrease of the sheet resistance to 9.20 (Ω/Box), the mobility increase up to 29.3(cm2/V·s), the transmittance up to 84% and the increase of the band gap up to 2.76(eV) state the sample CdO:F 3% is the best candidate for transparent and conducting oxide application.

  11. Flame spray pyrolysis: An enabling technology for nanoparticles design and fabrication.

    PubMed

    Teoh, Wey Yang; Amal, Rose; Mdler, Lutz

    2010-08-01

    Combustion of appropriate precursor sprays in a flame spray pyrolysis (FSP) process is a highly promising and versatile technique for the rapid and scalable synthesis of nanostuctural materials with engineered functionalities. The technique was initially derived from the fundamentals of the well-established vapour-fed flame aerosols reactors that was widely practised for the manufacturing of simple commodity powders such as pigmentary titania, fumed silica, alumina, and even optical fibers. In the last 10 years however, FSP knowledge and technology was developed substantially and a wide range of new and complex products have been synthesised, attracting major industries in a diverse field of applications. Key innovations in FSP reactor engineering and precursor chemistry have enabled flexible designs of nanostructured loosely-agglomerated powders and particulate films of pure or mixed oxides and even pure metals and alloys. Unique material morphologies such as core-shell structures and nanorods are possible using this essentially one step and continuous FSP process. Finally, research challenges are discussed and an outlook on the next generation of engineered combustion-made materials is given. PMID:20820719

  12. Chemical spray pyrolysis of ?-In2S3 thin films deposited at different temperatures

    NASA Astrophysics Data System (ADS)

    Sall, Thierno; Mar Soucase, Bernab; Mollar, Miguel; Hartitti, Bouchaib; Fahoume, Mounir

    2015-01-01

    In2S3 thin films were deposited onto indium tin oxide-coated glass substrates by chemical spray pyrolysis while keeping the substrates at different temperatures. The structures of the sprayed In2S3 thin films were characterized by X-ray diffraction (XFD). The quality of the thin films was determined by Raman spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy were used to explore the surface morphology and topography of the thin films, respectively. The optical band gap was determined based on optical transmission measurements. The indium sulfide phase exhibited a preferential orientation in the (0, 0, 12) crystallographic direction according to the XRD analysis. The phonon vibration modes determined by Raman spectroscopy also confirmed the presence of the In2S3 phase in our samples. According to SEM, the surface morphologies of the films were free of defects. The optical band gap energy varied from 2.82 eV to 2.95 eV.

  13. Flame spray pyrolysis: An enabling technology for nanoparticles design and fabrication

    NASA Astrophysics Data System (ADS)

    Teoh, Wey Yang; Amal, Rose; Mdler, Lutz

    2010-08-01

    Combustion of appropriate precursor sprays in a flame spray pyrolysis (FSP) process is a highly promising and versatile technique for the rapid and scalable synthesis of nanostuctural materials with engineered functionalities. The technique was initially derived from the fundamentals of the well-established vapour-fed flame aerosols reactors that was widely practised for the manufacturing of simple commodity powders such as pigmentary titania, fumed silica, alumina, and even optical fibers. In the last 10 years however, FSP knowledge and technology was developed substantially and a wide range of new and complex products have been synthesised, attracting major industries in a diverse field of applications. Key innovations in FSP reactor engineering and precursor chemistry have enabled flexible designs of nanostructured loosely-agglomerated powders and particulate films of pure or mixed oxides and even pure metals and alloys. Unique material morphologies such as core-shell structures and nanorods are possible using this essentially one step and continuous FSP process. Finally, research challenges are discussed and an outlook on the next generation of engineered combustion-made materials is given.

  14. Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS

    SciTech Connect

    Antonakou, E.V.; Kalogiannis, K.G.; Stephanidis, S.D.; Triantafyllidis, K.S.; Lappas, A.A.; Achilias, D.S.

    2014-12-15

    Highlights: • Thermal and catalytic pyrolysis is a powerful method for recycling of WEEEs. • Liquid products obtained from the pyrolysis of PC or HIPS found in waste CDs are very different. • Mainly phenols are obtained from pyrolysis PC based wastes while aromatics from HIPS. • Use of MgO catalyst increases the amount of phenols from CD recycling compared to ZSM-5. • Use of MgO or ZSM-5 catalysts reduces the amount of styrene recovered from HIPS. - Abstract: Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds.

  15. Fabrication of gradient porous LSM cathode by optimizing deposition parameters in ultrasonic spray pyrolysis

    SciTech Connect

    Hamedani, Hoda A.; Dahmen, Klaus-Hermann; Li, Dongsheng; Peydaye-Saheli, Houman; Garmestani, Hamid; Khaleel, Mohammad A.

    2008-10-07

    Multiple-step ultrasonic spray pyrolysis was developed to produce a gradient porous lanthanum strontium manganite (LSM) cathode on yttria-stabilized zirconia (YSZ) electrolyte for use in intermediate temperature solid oxide fuel cells (IT-SOFCs). The effect of solvent and precursor type on the morphology and compositional homogeneity of the LSM film was first identified. The LSM film prepared from organo-metallic precursor and organic solvent showed a homogeneous crack-free microstructure before and after heat treatment as opposed to aqueous solution. With respect to the effect of processing parameters, increasing the temperature and solution flow rate in the specific range of 520580 C leads to change the microstructure from a dense to a highly porous structure. Using a dilute organic solution a nanocrystalline thin layer was first deposited at 520 C and solution flow rate of 0.73 ml/min on YSZ surface; then, three gradient porous layers were sprayed from concentrated solution at higher temperatures (540580 C) and solution flow rates (1.131.58 ml/min) to form a gradient porous LSM cathode film with 30 ?m thickness. The microstructure, phase crystallinity and compositional homogeneity of the fabricated films were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive analysis of X-ray (EDX). Results showed that the spray pyrolized gradient film fabricated in the temperature range of 520580 C is composed of highly crystalline LSM phase which can remove the need for subsequent heat treatment.

  16. Rapid synthesis of spherical-shaped green-emitting MgGa{sub 2}O{sub 4}:Mn{sup 2+} phosphor via spray pyrolysis

    SciTech Connect

    Choi, Sungho; Kim, Kyoungun; Moon, Young-Min; Park, Byung-Yoon; Jung, Ha-Kyun

    2010-08-15

    Simple, one-step synthesis of spherical-shaped powder phosphors with aqueous precursors via a spray pyrolysis method is reported. Green-emitting MgGa{sub 2}O{sub 4}:Mn{sup 2+} phosphor with a controlled shape was successfully obtained by spraying under a reductive atmosphere (N{sub 2} + H{sub 2} carrier gas) without high-temperature post-heat treatment. In addition, the corresponding powder phosphors were well dispersed and showed a clean surface morphology compared to an existing cumbersome process using high-temperature post-annealing. The new method may help to prevent surface residual non-radiative defect sites. The result of highly luminescent and spherical morphology, non-aggregated powder phosphor by this procedure holds promise for a cost-effective and rapid synthesis process for conventional inorganic phosphors.

  17. Properties of NiO thin films deposited by chemical spray pyrolysis using different precursor solutions

    NASA Astrophysics Data System (ADS)

    Cattin, L.; Reguig, B. A.; Khelil, A.; Morsli, M.; Benchouk, K.; Bernède, J. C.

    2008-07-01

    NiO thin films have been deposited by chemical spray pyrolysis using a perfume atomizer to grow the aerosol. The influence of the precursor, nickel chloride hexahydrate (NiCl 2·6H 2O), nickel nitrate hexahydrate (Ni(NO 3) 2·6H 2O), nickel hydroxide hexahydrate (Ni(OH) 2·6H 2O), nickel sulfate tetrahydrate (NiSO 4·4H 2O), on the thin films properties has been studied. In the experimental conditions used (substrate temperature 350 °C, precursor concentration 0.2-0.3 M, etc.), pure NiO thin films crystallized in the cubic phase can be achieved only with NiCl 2 and Ni(NO 3) 2 precursors. These films have been post-annealed at 425 °C for 3 h either in room atmosphere or under vacuum. If all the films are p-type, it is shown that the NiO films conductivity and optical transmittance depend on annealing process. The properties of the NiO thin films annealed under room atmosphere are not significantly modified, which is attributed to the fact that the temperature and the environment of this annealing is not very different from the experimental conditions during spray deposition. The annealing under vacuum is more efficient. This annealing being proceeded in a vacuum no better than 10 -2 Pa, it is supposed that the modifications of the NiO thin film properties, mainly the conductivity and optical transmission, are related to some interaction between residual oxygen and the films.

  18. Comparative study of ITO and FTO thin films grown by spray pyrolysis

    SciTech Connect

    Ait Aouaj, M.; Diaz, R.; Belayachi, A.; Rueda, F.; Abd-Lefdil, M.

    2009-07-01

    Tin doped indium oxide (ITO) and fluorine doped tin oxide (FTO) thin films have been prepared by one step spray pyrolysis. Both film types grown at 400 deg. C present a single phase, ITO has cubic structure and preferred orientation (4 0 0) while FTO exhibits a tetragonal structure. Scanning electron micrographs showed homogeneous surfaces with average grain size around 257 and 190 nm for ITO and FTO respectively. The optical properties have been studied in several ITO and FTO samples by transmittance and reflectance measurements. The transmittance in the visible zone is higher in ITO than in FTO layers with a comparable thickness, while the reflectance in the infrared zone is higher in FTO in comparison with ITO. The best electrical resistivity values, deduced from optical measurements, were 8 x 10{sup -4} and 6 x 10{sup -4} {Omega} cm for ITO (6% of Sn) and FTO (2.5% of F) respectively. The figure of merit reached a maximum value of 2.15 x 10{sup -3} {Omega}{sup -1} for ITO higher than 0.55 x 10{sup -3} {Omega}{sup -1} for FTO.

  19. Hydrophilic CdSe thin films by low cost spray pyrolysis technique and annealing effects

    NASA Astrophysics Data System (ADS)

    Logu, T.; Sankarasubramanian, K.; Soundarrajan, P.; Sethuraman, K.

    2015-03-01

    Cadmium selenide (CdSe) thin films were deposited on glass substrates at 200C by homemade chemical spray pyrolysis technique. The as-deposited films were annealed in air atmosphere for 3 hrs, at two different temperatures (350 and 450C). The as-deposited film has been observed to possess uniform surface with crystalline sphalerite cubic structure and optical band gap of E g = 2.4 eV. It is worth noting that after annealing, metastable cubic sphalerite phase transforms into stable well crystalline hexagonal wurtzite phase. The optical band gap was found to decrease from 2.4 eV to 1.75 eV. The average surface roughness is 1.5 nm for the as-deposited film which rises to 4.2 nm after annealing the film in air atmosphere. The contact angle was found to vary from 94 1 to 81 1 with annealing temperature. In addition, from Wenzel's relation it is concluded that CdSe thin film is hydrophilic in nature. [Figure not available: see fulltext.

  20. Spray pyrolysis synthesis of ZnS nanoparticles from a single-source precursor

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Zhang, Hongwang; Swihart, Mark T.

    2009-06-01

    ZnS, a II-VI semiconductor with a relatively high direct bandgap (~3.6 eV) in the near-UV region, has potential applications in areas such as solar cells, lasers and displays. In addition, ZnS nanoparticles can be applied as phosphors, probes for bioimaging, emitters in light emitting diodes and photocatalysts. Here, we report synthesis of cubic ZnS nanoparticles from a low-cost single-source precursor in a continuous spray pyrolysis reactor. In this approach, the evaporation and decomposition of precursor and nucleation of particles occur sequentially. Product particles were characterized by HRTEM, XRD, and EDX. Particles with diameters ranging from 2 to 7 nm were produced. HF was used to remove ZnO impurities and other surface contamination. As-synthesized ZnS nanoparticles exhibit blue photoluminescence near 440 nm under UV excitation and have quantum yields up to 15% after HF treatment. This demonstrates a potentially general approach for continuous low-cost synthesis of semiconductor quantum dots for applications where tight control of the size distribution is less important than scalable, economical production.

  1. Gas sensing properties of nanostructured MoO3 thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Martnez, H. M.; Torres, J.; Rodrguez-Garca, M. E.; Lpez Carreo, L. D.

    2012-08-01

    Thin films of molybdenum trioxide (MoO3) were deposited on common glass using the chemical spray pyrolysis technique. A (NH4)6Mo7O244H20 solution 0.1 M was used as the precursor one. The influence of substrate temperature on the crystallographic structure, surface morphology and electrical behavior of MoO3 thin films was studied. MoO3 can exist in two crystalline forms, the thermodynamically stable orthorhombic ?-MoO3 and the metastable monoclinic ?-MoO3 phase. XRD-spectra showed a growth of ?-MoO3 phase percentage as substrate temperature increases from 420 K up to 670 K. Films deposited in the 500-600 K range have a clearly porous surface structure of nanometer order as can be seen in SEM images. Changes up to six magnitude orders were observed in MoO3 thin films electrical resistance when films temperature varied from 100 K up to 500 K. The sensing property of these MoO3 films was also studied. The sensitivity was investigated in the temperature range 160 and 360 K for H2O and CO gases, respectively. Both of them are of reducing nature. In all studied cases sensitivity decreases slowly as film temperature is raised. At room temperature the sensitivity changes from 12 up to 75% depending on substrate temperature. The sensitivity for CO gas was found to be lower than that of H2O.

  2. Synthesis of nanocrystalline Cu2ZnSnS4 thin films grown by the spray-pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Chandel, Tarun; Singh, Joginder; Rajaram, P.

    2015-08-01

    Spray pyrolysis was used to deposit Cu2ZnSnS4 (CZTS) thin films on soda lime glass substrates at 300 °C. Aqueous solutions of copper chloride, zinc chloride, stannous chloride and thiourea were mixed together to form the spray liquid. The sprayed films were annealed under vacuum at 350 °C, 400 °C and 450 °C. Structural and optical characterization was performed on the CZTS films using X-ray diffraction (XRD) and UV-VIS spectrophotometry. XRD results indicate that the films are single phase nanocrystalline CZTS. Optical studies show that the optical gap values are 1.44 eV for the as-grown film and 1.46 eV, 1.48 eV and 1.49 eV for the films annealed at 350 °C, 400 °C and 450 °C, respectively.

  3. In vitro and in vivo antimicrobial properties of silver-containing hydroxyapatite prepared via ultrasonic spray pyrolysis route.

    PubMed

    Honda, Michiyo; Kawanobe, Yusuke; Ishii, Ken; Konishi, Toshiisa; Mizumoto, Minori; Kanzawa, Nobuyuki; Matsumoto, Morio; Aizawa, Mamoru

    2013-12-01

    Hydroxyapatite (HAp), with its high biocompatibility and osteoconductivity, readily absorbs proteins, amino acids and other substances, which in turn favor the adsorption and colonization of bacteria. To prevent bacterial growth and biofilm formation on HAp discs, silver-containing (1-20 mol%) HAp (Ag-HAp) powders were synthesized using an ultrasonic spray pyrolysis (USSP) technique. The X-ray diffraction (XRD) peaks were very broad, indicating low crystallinity, and this induced the release of Ag(+) ions from Ag-HAp powders. In addition, a gradual increase in Ca(2+) ion release was observed. These results suggest that dissolution of Ca(2+) ion in Ag-HAp triggered the release of Ag(+) ions. The antimicrobial efficacy of Ag-HAp disc was tested against Staphylococcus aureus. Samples with Ag contents of more than 5 mol% were found to be highly effective against bacterial colonization and biofilm formation in vitro. In vivo antibacterial tests using bioluminescent strains also showed reductions in the viability of bacteria with Ag-HAp (5 mol%) discs. Biocompatibility tests using a modified Transwell insert method showed that Ag-HAp (5 mol%) discs have negative effects on osteoblast proliferation. These results indicate that Ag-HAp (5 mol%) has effective antibacterial activity and good biocompatibility both in vitro and in vivo together with good biocompatibility, thus confirming its utility as a bactericidal material. PMID:24094218

  4. Correlation between porous structure and electrochemical properties of porous nanostructured vanadium pentoxide synthesized by novel spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Kong, Long; Taniguchi, Izumi

    2016-04-01

    Porous nanostructured vanadium pentoxide (V2O5) particles were successfully prepared by spray pyrolysis (SP) in a precursor solution with an ammonium nitrate (NH4NO3) additive. The correlation between the porous structure and the electrochemical properties of the V2O5 particles was investigated. The porous structure markedly changed upon increasing the concentration of NH4NO3 in the precursor solution from 0 to 0.408 mol L-1. Pore structure analysis based on N2 adsorption-desorption isotherm measurements indicated that porous nanostructured V2O5 particles with a pore size of less than 100 nm can be prepared by the novel SP method and that an increase in the NH4NO3 concentration in the precursor solution can enlarge the pores in the V2O5 particles, especially those with a size between 20 and 80 nm. The porous nanostructured V2O5 prepared with an NH4NO3 concentration of 0.272 mol L-1 exhibited a first discharge capacity of 400 mAh g-1 at 20 mA g-1. The unique porous structure of V2O5 particles significantly enhanced the rate performance and exhibited a first discharge capacity of 180 mAh g-1 at 1200 mA g-1, which is much higher than that of dense V2O5 particles (70 mAh g-1).

  5. Study of Optical and Electrical Properties of In2S3:Sn Films Deposited by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Kraini, M.; Bouguila, N.; Halidou, I.; Moadhen, A.; Vázquez-Vázquez, C.; López-Quintela, M. A.; Alaya, S.

    2015-07-01

    Tin-doped In2S3 films were grown by the chemical spray pyrolysis method using compressed air as a carrier gas. Tin is incorporated in the solution using SnCl4. Structural and optical properties of films were investigated by x-ray diffraction (XRD), absorption, Raman and photoluminescence spectroscopies. Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy were used to explore the surface morphology. The properties of In2S3 thin films are influenced by Sn doping. XRD studies revealed that the deposited films were polycrystalline in nature exhibiting cubic structure and oriented preferentially towards (111). According to FESEM, the surface morphology of the films was free of defects. Raman studies showed different peaks related to In2S3 phase and did not show any secondary phases of In-Sn and Sn-S. In2S3:Sn films exhibited transparency over 60-85% in the visible and infrared regions. The optical band gap was found to vary in the range 2.71-2.58 eV for direct transitions. The room temperature photoluminescence (PL) studies revealed two PL bands, centered at 529 nm (band A) and 725 nm (band B). From these results, one can conclude that our material can be used as transmittive windows in low-cost solar cells. The conductance and capacitance characterization at ambient temperature were also investigated and gave interesting physical properties for photovoltaic applications.

  6. Luminescence properties of Eu-complex formations into ordered mesoporous silica particles obtained by the spray pyrolysis process

    NASA Astrophysics Data System (ADS)

    Rocha, Lucas A.; Freiria, Janaina do C.; Caiut, José Maurício A.; Ribeiro, Sidney J. L.; Messaddeq, Younes; Verelst, Marc; Dexpert-Ghys, Jeannette

    2015-08-01

    Ordered mesoporous, highly luminescent SiO2 particles have been synthesized by spray pyrolysis from solutions containing tetraethylorthosilicate (TEOS), Eu(NO3)3.6H2O, and cetyltrimethylammonium bromide (CTAB) as structure-directing agents. The 1,10-phenantroline (Phen) molecules were coordinated in a post-synthesis step by a simple wet impregnation method. In addition, other matrices were also prepared by the encapsulation of europium complex Eu(fod)3 (where fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) into mesoporous silica, and then the Phen molecules were encapsulated by different impregnation steps, after which the luminescence properties were investigated. The obtained materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder x-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Powders with polydisperse spherical grains were obtained, displaying an ordered hexagonal array of mesochannels. Luminescence results revealed that Phen molecules had been successfully coordinated as an additional ligand in the Eu(fod)3 complex into the channels of the mesoporous particles without disrupting the structure.

  7. Evolution of Zinc Oxide Nanostructures Grown on Graphene by Ultrasonic Spray Pyrolysis and Its Statistical Growth Modelling

    NASA Astrophysics Data System (ADS)

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-11-01

    The evolution of zinc oxide nanostructures grown on graphene by alcohol-assisted ultrasonic spray pyrolysis was investigated. The evolution of structures is strongly depended on pyrolysis parameters, i.e., precursor molarity, precursor flow rate, precursor injection/deposition time, and substrate temperature. Field-effect scanning electron microscope analysis, energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy were used to investigate the properties of the synthesized nanostructures and to provide evidence for the structural changes according to the changes in the pyrolysis parameters. The optimum parameters to achieve maximum density and well-defined hexagonally shaped nanorods were a precursor molarity of 0.2 M, an injection flow rate of 6 ml/min, an injection time of 10 min, and a substrate temperature of 250-355 °C. Based on the experimental results, the response surface methodology (RSM) was used to model and optimize the independent pyrolysis parameters using the Box-Behnken design. Here, the responses, i.e., the nanostructure density, size, and shape factor, are evaluated. All of the computations were performed using the Design-Expert software package. Analysis of variance (ANOVA) was used to evaluate the results of the model and to determine the significant values for the independent pyrolysis parameters. The evolution of zinc oxide (ZnO) structures are well explained by the developed modelling which confirms that RSM is a reliable tool for the modelling and optimization of the pyrolysis parameters and prediction of nanostructure sizes and shapes.

  8. Evolution of Zinc Oxide Nanostructures Grown on Graphene by Ultrasonic Spray Pyrolysis and Its Statistical Growth Modelling.

    PubMed

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-12-01

    The evolution of zinc oxide nanostructures grown on graphene by alcohol-assisted ultrasonic spray pyrolysis was investigated. The evolution of structures is strongly depended on pyrolysis parameters, i.e., precursor molarity, precursor flow rate, precursor injection/deposition time, and substrate temperature. Field-effect scanning electron microscope analysis, energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy were used to investigate the properties of the synthesized nanostructures and to provide evidence for the structural changes according to the changes in the pyrolysis parameters. The optimum parameters to achieve maximum density and well-defined hexagonally shaped nanorods were a precursor molarity of 0.2 M, an injection flow rate of 6 ml/min, an injection time of 10 min, and a substrate temperature of 250-355 °C. Based on the experimental results, the response surface methodology (RSM) was used to model and optimize the independent pyrolysis parameters using the Box-Behnken design. Here, the responses, i.e., the nanostructure density, size, and shape factor, are evaluated. All of the computations were performed using the Design-Expert software package. Analysis of variance (ANOVA) was used to evaluate the results of the model and to determine the significant values for the independent pyrolysis parameters. The evolution of zinc oxide (ZnO) structures are well explained by the developed modelling which confirms that RSM is a reliable tool for the modelling and optimization of the pyrolysis parameters and prediction of nanostructure sizes and shapes. PMID:26608535

  9. Effect of Annealing Temperature on the Performance of SnO2 Thin Film Transistors Prepared by Spray Pyrolysis.

    PubMed

    Zhang, XinAn; Zhai, JunXia; Yu, XianKun; Zhu, RuiJuan; Zhang, WeiFeng

    2015-08-01

    We fabricated SnO2 thin film transistors on thermally oxidized p-type silicon substrates by low-cost spray pyrolysis. The effect of annealing temperatures on electrical characteristics of SnO2 thin film transistors were investigated. Thermal annealing at higher temperatures induced a negative shift of the threshold voltage (VT) and an increase in the saturation mobility. It was found that the device annealed at 450 C exhibited a good electrical performance with the field-effect mobility of 0.19 cm2/Vs, the threshold voltage of 2.5 V, and the on/off current ratio of 10(3). PMID:26369222

  10. Effect of Sb doping on the properties of SnO2 thin films grown by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Gupta, Archana; Rajaram, P.; Bhatnagar, M. C.

    2012-06-01

    Thin film of antimony doped Tin Oxide have been prepared using an economic spray pyrolysis technique. The films were deposited onto glass substrates at 450°C. The mesostructured tin oxide thin films with various Sb concentrations exhibited highly selective response towards CO. The novelty of the present sensor material is its mesostructured nature with high sensitivity and selectivity towards CO at 350°C The correlation of the antimony incorporation in the mesostructure with morphology and structure is discussed based on the results of scanning electron microscopy (SEM), X-ray diffraction (XRD), AFM and gas sensing behavior.

  11. Methods and apparatuses for deoxygenating biomass-derived pyrolysis oil

    SciTech Connect

    Baird, Lance Awender; Brandvold, Timothy A.

    2015-10-20

    Embodiments of methods and apparatuses for deoxygenating a biomass-derived pyrolysis oil are provided. In one example, a method comprises the steps of separating a low-oxygen biomass-derived pyrolysis oil effluent into a low-oxygen-pyoil organic phase stream and an aqueous phase stream. Phenolic compounds are removed from the aqueous phase stream to form a phenolic-rich diluent recycle stream. A biomass-derived pyrolysis oil stream is diluted and heated with the phenolic-rich diluent recycle stream to form a heated diluted pyoil feed stream. The heated diluted pyoil feed stream is contacted with a deoxygenating catalyst in the presence of hydrogen to deoxygenate the heated diluted pyoil feed stream.

  12. Apparatus and method for spraying liquid materials

    DOEpatents

    Alvarez, J.L.; Watson, L.D.

    1988-01-21

    A method for spraying liquids involving a flow of gas which shears the liquid. A flow of gas is introduced in a converging-diverging nozzle where it meets and shears the liquid into small particles which are of a size and uniformity which can be controlled through adjustment of pressures and gas velocity. 5 figs.

  13. Apparatus and method for spraying liquid materials

    DOEpatents

    Alvarez, Joseph L. (Idaho Falls, ID); Watson, Lloyd D. (Rigby, ID)

    1990-01-01

    A method for spraying liquids involving a flow of gas which shears the liquid. A flow of gas is introduced in a converging-diverging nozzle where it meets and shears the liquid into small particles which are of a size and uniformity which can be controlled through adjustment of pressures and gas velocity.

  14. Characteristic of Low Resistivity Fluorine-Doped SnO2 Thin Films Grown by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Oshima, Minoru; Yoshino, Kenji

    2011-05-01

    Transparent conducting oxide films of fluorine-doped SnO2 (FTO) were deposited on glass substrates by spray pyrolysis in order to determine the effect of spray solution concentration. These films were prepared with different F-doping concentrations from 0 to 33 mol %. The films were all polycrystalline with tetragonal crystal structures. The best electro-optic properties were achieved with a fluorine doping concentration of 17 mol % at a substrate temperature of 500 °C. These conditions resulted in a film with an average transmittance of 82%, a resistivity of 4.0 ×10-4 Ω cm, a carrier concentration of 4.7 ×1020 cm-3 and a mobility of 34 cm2 V-1 s-1.

  15. Leidenfrost temperature related CVD-like growth mechanism in ZnO-TFTs deposited by pulsed spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Ortel, Marlis; Wagner, Veit

    2013-01-01

    Zinc oxide thin films were prepared by pulsed spray pyrolysis (SP) from aqueous zinc acetate precursor solution. The deposition behavior of the solution with regard to the pool boiling curve of the solvent was investigated to gain insights of the deposition mechanism which leads to homogeneous and reproducible ZnO layers. The Leidenfrost effect was found to play an important role since the Leidenfrost temperature has to be exceeded to form high quality layers. It is concluded that 3D nucleation of ZnO nano-crystals takes place out of the gaseous phase by a CVD-like process on ITO as well as on SiO2 substrates. Crystal orientation and surface roughness of the zinc oxide layer are found to depend strongly on the substrate. An increasing grain size with film thickness is observed. These findings were utilized to fabricate and investigate the semiconducting properties of the films in ZnO thin film transistors (TFTs). The mobility exceeded 12 cm2 V-1 s-1, the on-set was at 1 V and the on-off current ratio was found to be higher than 108. Hence the morphology and the electrical parameters of the ZnO films deposited by pulsed spray pyrolysis from non-toxic aqueous zinc acetate solution above the Leidenfrost point show excellent properties for electronic applications.

  16. Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Shasti, M.; Mortezaali, A.; Dariani, R. S.

    2015-01-01

    In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

  17. Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

    SciTech Connect

    Shasti, M.; Mortezaali, A. Dariani, R. S.

    2015-01-14

    In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

  18. Low oxygen biomass-derived pyrolysis oils and methods for producing the same

    SciTech Connect

    Marinangeli, Richard; Brandvold, Timothy A; Kocal, Joseph A

    2013-08-27

    Low oxygen biomass-derived pyrolysis oils and methods for producing them from carbonaceous biomass feedstock are provided. The carbonaceous biomass feedstock is pyrolyzed in the presence of a catalyst comprising base metal-based catalysts, noble metal-based catalysts, treated zeolitic catalysts, or combinations thereof to produce pyrolysis gases. During pyrolysis, the catalyst catalyzes a deoxygenation reaction whereby at least a portion of the oxygenated hydrocarbons in the pyrolysis gases are converted into hydrocarbons. The oxygen is removed as carbon oxides and water. A condensable portion (the vapors) of the pyrolysis gases is condensed to low oxygen biomass-derived pyrolysis oil.

  19. Modifying Optical Properties of ZnO Films by Forming Zn[subscript 1-x] Co[subscript x]O Solid Solutions via Spray Pyrolysis

    ERIC Educational Resources Information Center

    Bentley, Anne K.; Weaver, Gabriela C.; Russell, Cianan B.; Fornes, William L.; Choi, Kyoung-Shin; Shih, Susan M.

    2007-01-01

    A simple and cost-effective experiment for the development and characterization of semiconductors using Uv-vis spectroscopy is described. The study shows that the optical properties of ZnO films can be easily modified by forming Zn[subscript 1-x] Co[subscript x]O solid solutions via spray pyrolysis.

  20. Effect of Catalytic Pyrolysis Conditions Using Pulse Current Heating Method on Pyrolysis Products of Wood Biomass

    PubMed Central

    Honma, Sensho; Hata, Toshimitsu; Watanabe, Takashi

    2014-01-01

    The influence of catalysts on the compositions of char and pyrolysis oil obtained by pyrolysis of wood biomass with pulse current heating was studied. The effects of catalysts on product compositions were analyzed using GC-MS and TEM. The compositions of some aromatic compounds changed noticeably when using a metal oxide species as the catalyst. The coexistence or dissolution of amorphous carbon and iron oxide was observed in char pyrolyzed at 800C with Fe3O4. Pyrolysis oil compositions changed remarkably when formed in the presence of a catalyst compared to that obtained from the uncatalyzed pyrolysis of wood meal. We observed a tendency toward an increase in the ratio of polyaromatic hydrocarbons in the pyrolysis oil composition after catalytic pyrolysis at 800C. Pyrolysis of biomass using pulse current heating and an adequate amount of catalyst is expected to yield a higher content of specific polyaromatic compounds. PMID:25614894

  1. Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

    SciTech Connect

    Martinez, H.M.; Torres, J.; Lopez Carreno, L.D.; Rodriguez-Garcia, M.E.

    2013-01-15

    Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO{sub 3} (H{sub 2}O){sub 2} was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into {alpha}-MoO{sub 3}. The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO{sub 3} films' sensitivity was analyzed for CO and H{sub 2}O in the temperature range 160 to 360 K; the results indicate that CO and H{sub 2}O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H{sub 2}O. - Highlights: Black-Right-Pointing-Pointer A low cost technique is used which produces good material. Black-Right-Pointing-Pointer Thin films are prepared using ammonium molybdate tetra hydrated. Black-Right-Pointing-Pointer The control of the physical properties of the samples could be done. Black-Right-Pointing-Pointer A calculation method is proposed to determine the material optical properties. Black-Right-Pointing-Pointer The MoO{sub 3} thin films prepared by spray pyrolysis could be used as gas sensor.

  2. Apparatuses and methods for deoxygenating biomass-derived pyrolysis oil

    SciTech Connect

    Kalnes, Tom N.

    2015-12-29

    Apparatuses and methods for deoxygenating a biomass-derived pyrolysis oil are provided herein. In one example, the method comprises of dividing a feedstock stream into first and second feedstock portions. The feedstock stream comprises the biomass-derived pyrolysis oil and has a temperature of about 60.degree. C. or less. The first feedstock portion is combined with a heated organic liquid stream to form a first heated diluted pyoil feed stream. The first heated diluted pyoil feed stream is contacted with a first deoxygenating catalyst in the presence of hydrogen to form an intermediate low-oxygen pyoil effluent. The second feedstock portion is combined with the intermediate low-oxygen pyoil effluent to form a second heated diluted pyoil feed stream. The second heated diluted pyoil feed stream is contacted with a second deoxygenating catalyst in the presence of hydrogen to form additional low-oxygen pyoil effluent.

  3. Investigations of superparamagnetism in magnesium ferrite nano-sphere synthesized by ultrasonic spray pyrolysis technique for hyperthermia application

    NASA Astrophysics Data System (ADS)

    Das, Harinarayan; Sakamoto, Naonori; Aono, Hiromichi; Shinozaki, Kazuo; Suzuki, Hisao; Wakiya, Naoki

    2015-10-01

    In this paper, we present the synthesized of magnesium ferrite (MgFe2O4) nano-spheres by a single-step ultrasonic spray pyrolysis (USP) technique from the aqueous metal nitrate precursor solution without any organic additives or post-annealing processes. The effects of different pyrolysis temperatures on the particles size, morphology and their superparamagnetic behavior have been investigated to evaluate the heat generation efficiency in an AC magnetic field. The X-ray powder diffraction spectra of MgFe2O4 nano-spheres synthesized at the pyrolysis temperatures of 600, 700, 800 and 900 C exhibited single phase cubic structure and obtained mean crystallite size (primary particles) of 4.05, 9.6, 15.97 and 31.48 nm, respectively. Transmission electron microscopy (TEM) confirms that the particles consisted of aggregates of the primary crystallite had densely congested spherical morphology with extremely smooth surface appearance. Field emission electron microscopy (FESEM) reveals that the shape and size of the nano-spheres (secondary particles) does not change significantly but the degree of agglomeration between the secondary particles was reduced with increasing the pyrolysis temperature. The average size and size distribution of nano-spheres measured using electrophoretic scattering photometer have found very low polydispersity index (PDI) for all samples. The field dependent magnetization studies indicated superparamagnetic nature for the particles having crystallite size i.e. 4.05 and 9.6 nm and exhibited ferromagnetic nature for 15.97 and 31.48 nm. It is also demonstrated that, as the pyrolysis temperature increases, the saturation magnetization of the MgFe2O4 nanopowders increases due to enhancement of crystallites. The shift in Curie temperature is well described by the finite-size scaling formula. The magnetically loss heating values of selected samples in crystallite size of 9.6 and 15.97 nm were investigated by measuring the time dependent temperature curves in an external alternating magnetic field (370 kHz, 1.77 kA/m). The more heat generation ability was obtained for 9.6 nm in crystal size because of minimum squareness ratio with coercivity in superparamagnetic range. The results reported in this study are useful to find out of superparamagnetic limit for the preparation of MgFe2O4 nanopowders.

  4. Ethylene glycol assisted spray pyrolysis for the synthesis of hollow BaFe12O19 spheres

    SciTech Connect

    Xu, X; Park, J; Hong, YK; Lane, AM

    2015-04-01

    Hollow spherical BaFe12O19 particles were synthesized by spray pyrolysis from a solution containing ethylene glycol (EG) and precursors at 1000 degrees C. The effects of EG concentration on particle morphology, crystallinity and magnetic properties were investigated. The hollow spherical particles were found to consist of primary particles, and higher EG concentration led to a bigger primary particle size. EG concentration did not show much effect on the hollow particle size. Better crystallinity and higher magnetic coercivity were obtained with higher EG concentration, which is attributed to further crystallization with the heat produced from EG combustion. Saturation magnetization (emu/g) decreased with increasing EG concentration due to residual carbon from EG incomplete combustion, contributing as a non-magnetic phase to the particles. Published by Elsevier B.V.

  5. Effect of annealing on the properties of zinc oxide nanofiber thin films grown by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Sadananda Kumar, N.; Bangera, Kasturi V.; Shivakumar, G. K.

    2013-01-01

    Zinc oxide nanofiber thin films have been deposited on glass substrate by spray pyrolysis technique. The X-ray diffraction studies revealed that the films are polycrystalline with the hexagonal structure and a preferred orientation along (002) direction for films annealed for 1 h at 450 C. Further increase in annealing time changes the preferred orientation to (100) direction. The scanning electron microscopic analysis showed the formation of ZnO nanofiber with an average diameter of approximately 800 nm for annealed films. The compositional analysis of nanofiber ZnO thin films were studied by time of flight secondary ion mass spectroscopy, which indicated oxygen deficiency in the films. The optical properties of annealed films have shown a variation in the band gap between 3.29 and 3.20 eV. The electrical conductivity of the as grown and annealed films showed an increase in the conductivity by two orders of magnitude with increase in annealing duration.

  6. Effect of annealing on the properties of Sb doped ZnO thin films prepared by spray pyrolysis technique

    SciTech Connect

    Kumar, N. Sadananda; Bangera, Kasturi V.; Shivakumar, G. K.

    2014-01-28

    Sb doped ZnO thin films have been deposited on glass substrate at 450C using spray pyrolysis technique. The X-ray diffraction studies revealed that the as deposited films are polycrystalline in nature with (100) preferred orientation. Whereas the films annealed at 450 C for 6h show a preferential orientation along (101) direction. Crystallites size varies from 15.7 nm to 34.95 nm with annealing duration. The Scanning electron microscopic analysis shows the plane and smooth surface of the films. The optical properties of annealed films have shown a variation in the band gap between 3.37 eV and 3.19 eV. Transparency of as grown and annealed films decreases from 78 % to 65% respectively in the visible region. The electrical conductivity of the as grown film shows an increase in the electrical conductivity by one order of magnitude with increase in the annealing duration.

  7. Effect of In doping on the properties and antibacterial activity of ZnO films prepared by spray pyrolysis.

    PubMed

    Manoharan, C; Pavithra, G; Dhanapandian, S; Dhamodharan, P

    2015-10-01

    Pure and In-doped ZnO thin films were deposited onto glass substrates by spray pyrolysis technique. XRD results showed that all films were polycrystalline in nature with the wurzite structure. A change in preferential orientation from (002) to (101) plane was observed with increase in content of Indium. A reduce in crystallite size was observed with increase of In content. The small sized grains with the porous nature of the film was observed from SEM analysis. AFM study depicted polycrystalline nature and uniformly distributed grains with small pores in the doped film. A decrease in band gap was noticed with increase in In content. The absence of green emission in PL spectra indicated the decreased oxygen defects. The decrease in the resistivity with increase of Hall mobility was noted for the doped film. A better antibacterial activity was observed against Staphylococcus aureus by doped ZnO thin film. PMID:25997176

  8. Optical, electrical and surface properties of annealed CdO:Mg thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Karakaya, Seniye; Ozbas, Omer

    2013-12-01

    The use of transparent conducting oxides in optoelectronic and photovoltaic devices has encouraged research on this field in recent years. Especially, cadmium oxide is a promising material for solar cell application but also for photodiodes and gas sensors. Mg doped CdO (CdO:Mg) films have been prepared on glass substrates by the ultrasonic spray pyrolysis (USP) technique. After the production, the films have been annealed in air atmosphere at 475°C and half hour. Results on surface, optical and electrical properties of the films as a function of the thermal annealing have been reported. Thicknesses of the films have been determined by the filmetrics thin film measurement system. Transmission and absorbance spectra have been taken by UV-vis spectrophotometer. Atomic Force Microscopy (AFM) analysis indicates that the roughness of the surface decreases upon increasing Mg concentration. The minimum resistivity value of the films was 2×10-3 Ω cm.

  9. Structural, optical, electrical and surface properties of Co-doped ZnO films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Gencyılmaz, O.; Atay, F.; Akyuz, I.

    2012-09-01

    In this study undoped and Co-doped ZnO films were prepared by ultrasonic spray pyrolysis technique. Co-doped ZnO films were obtained on glass substrates at different Co concentrations (at 2%, 4%) using zinc acetate and cobalt chloride as precursors. The effect of Co doping was investigated on the structural, optical, electrical and surface properties. The structural and physical properties of the films were studied by using X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), Spectroscopic Ellipsometry, UV-VIS Spectrophotometry and four-point probe techniques. Consequently available potential of Co doped ZnO films for technological applications was searched.

  10. One-step synthesis of bismuth molybdate catalysts via flame spray pyrolysis for the selective oxidation of propylene to acrolein.

    PubMed

    Schuh, K; Kleist, W; Hj, M; Trouillet, V; Jensen, A D; Grunwaldt, J-D

    2014-12-18

    Flame spray pyrolysis (FSP) of Bi(III)- and Mo(VI)-2-ethylhexanoate dissolved in xylene resulted in various nanocrystalline bismuth molybdate phases depending on the Bi/Mo ratio. Besides ?-Bi2Mo3O12 and ?-Bi2MoO6, FSP gave direct access to the metastable ?-Bi2Mo2O9 phase with high surface area (19 m(2) g(-1)). This phase is normally only obtained at high calcination temperatures (>560 C) resulting in lower surface areas. The ?-phase was stable up to 400 C and showed superior catalytic performance compared to ?- and ?-phases in selective oxidation of propylene to acrolein at temperatures relevant for industrial applications (360 C). PMID:25350295

  11. Dopant-induced bandgap shift in Al-doped ZnO thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hung-Chun Lai, Henry; Basheer, Tahseen; Kuznetsov, Vladimir L.; Egdell, Russell G.; Jacobs, Robert M. J.; Pepper, Michael; Edwards, Peter P.

    2012-10-01

    A series of 1 at. % Al-doped ZnO (AZO) films were deposited onto glass substrates by a spray pyrolysis technique. We find that the observed blue shift in the optical bandgap of 1% AZO films is dominated by the Burstein Moss effect. The Fermi level for an 807 nm thick AZO film rose by some 0.16 eV with respect to the edge of the conduction band. By controlling the film thickness, all AZO films exhibit the same lattice strain values. The influence of strain-induced bandgap shift was excluded by selecting films with nearly the same level of bandgap volume-deformation potentials, and the differences in out-plain strain and in-plain stress remained effectively constant.

  12. Low-temperature spray-pyrolysis of FeS2 films and their electrical and optical properties

    NASA Astrophysics Data System (ADS)

    Orletskii, I. G.; Mar'yanchuk, P. D.; Maistruk, E. V.; Solovan, M. N.; Brus, V. V.

    2016-01-01

    Iron disulfide (FeS2) films with a wide range of electrical resistivities 100 ? cm ? ? ? 800 k? cm, a high adhesion to the substrate, and a resistance to aggressive media have been prepared by the spray pyrolysis of aqueous solutions of the salts FeCl3 6H2O and (NH2)2CS at low temperatures in the range 250C ? T S ? 400C. It has been found that the FeS2 films have a high transmittance T ? 60-70% and are characterized by a sharp transmission edge. It has been shown that the optical band gap for direct ( E g op = 2.19-2.78 eV) and indirect ( E g 'op = 1.26-1.36 eV) optical transitions depends on the conditions of film preparation.

  13. Selective detection of ammonia using spray pyrolysis deposited pure and nickel doped ZnO thin films

    NASA Astrophysics Data System (ADS)

    Mani, Ganesh Kumar; Rayappan, John Bosco Balaguru

    2014-08-01

    This research paper reports the deposition of nanostructured pure and Ni-doped ZnO thin films deposited at the substrate temperature of 523 K using simple and economical spray pyrolysis technique and subsequently post annealed at 673 K in air atmosphere for 3 h. Ni-doping greatly affected the crystallographic orientation, surface morphology, roughness and room temperature sensing response. Noticeable change in the crystallite size, transmittance and electrical properties was observed. The room temperature sensing characteristics like selectivity, response recovery studies, range of detection, stability and reproducibility of the undoped and Ni-doped ZnO thin films were investigated. Especially, the sensing elements exhibited an excellent selectivity towards ammonia. A lower detection limit of 5 and 25 ppm was observed for undoped and Ni-doped ZnO thin films respectively. The upper detection range was widened to 1000 ppm for the Ni-doped film.

  14. Impact of active layer thickness in thin-film transistors based on Zinc Oxide by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Dominguez, Miguel A.; Flores, Francisco; Luna, Adan; Martinez, Javier; Luna-Lopez, Jose A.; Alcantara, Salvador; Rosales, Pedro; Reyes, Claudia; Ordua, Abdu

    2015-07-01

    In this work, the preparation of Zinc Oxide (ZnO) films by ultrasonic spray pyrolysis at low-temperature and its application in thin-film transistors (TFTs) are presented, as well, the impact of the active layer thickness and gate dielectric thickness in the electrical performance of the ZnO TFTs. A thinner active layer resulted in better transfer characteristics such as higher on/off-current ratio, while a thicker active layer resulted in better output characteristics. The ZnO films were deposited from 0.2 M precursor solution of Zinc acetate in methanol, using air as carrier gas on a hotplate at 200 C. The ZnO films obtained at 200 C were characterized by optical transmittance, Photoluminescence spectroscopy and X-ray diffraction.

  15. Optical, electrical and surface properties of annealed CdO:Mg thin films prepared by spray pyrolysis

    SciTech Connect

    Karakaya, Seniye E-mail: oozbas@ogu.edu.tr; Ozbas, Omer E-mail: oozbas@ogu.edu.tr

    2013-12-16

    The use of transparent conducting oxides in optoelectronic and photovoltaic devices has encouraged research on this field in recent years. Especially, cadmium oxide is a promising material for solar cell application but also for photodiodes and gas sensors. Mg doped CdO (CdO:Mg) films have been prepared on glass substrates by the ultrasonic spray pyrolysis (USP) technique. After the production, the films have been annealed in air atmosphere at 475C and half hour. Results on surface, optical and electrical properties of the films as a function of the thermal annealing have been reported. Thicknesses of the films have been determined by the filmetrics thin film measurement system. Transmission and absorbance spectra have been taken by UV-vis spectrophotometer. Atomic Force Microscopy (AFM) analysis indicates that the roughness of the surface decreases upon increasing Mg concentration. The minimum resistivity value of the films was 210{sup ?3} ? cm.

  16. Synthesis and characterization of earth abundant and nontoxic metal chalcogenides produced via aerosol spray pyrolysis for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Davis, Patrick John

    A novel synthesis technique for the production of copper zinc tin sulfide (CZTS) nanocrystals has been developed using aerosol spray pyrolysis. CZTS is a quaternary semiconducting material that shows promise as a replacement to common semiconductors such as CdTe and CIGS for use in photovoltaic devices. CIGS is currently being commercialized in the photovoltaic industry, but rare and expensive indium and gallium components threaten its long term viability. CZTS looks to be one of the best alternatives to CIGS with all earth abundant and non-toxic materials and recent impressive gains in efficiency. A number of synthesis techniques have been thoroughly studied and detailed previously. In our novel approach, we synthesis single phase nanocrystals, starting with zinc, copper, and tin diethyldithiocarbamate precursors in a toluene solvent. The precursor solution is aerosolized using an ultrasonic nebulizer wherein the droplets are vacuumed through a tube furnace and nucleation occurs. We reproducibly synthesize kesterite, Cu2ZnSnS4, nanocrystals. This technique continuously converts the chemical precursor into high-purity nanopowder with a production rate of ~50 mg/hour for an un-optimized, lab-scale reactor. Using the same precursor chemistry, we have also been able to deposit high-quality CZTS thin films directly onto Mo-coated Swiss glass substrates using the aerosol spray pyrolysis technique. A thorough discussion of the current photovoltaic field, the processing parameters and challenges of nanocrystal and thin film production, and the experimental results will be presented. Characterization via Raman spectroscopy, EDS, XRD, TEM and XPS will be offered along with future recommendations and considerations.

  17. Lithium Content and Low-Temperature Conductivity of NiO:Li Films Deposited by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Garduño-Wilches, Ismael Arturo; Rodríguez-Fernández, Luis; Alonso, Juan Carlos

    2015-11-01

    The objective of this work was to quantify the amount of lithium incorporated into nickel oxide thin films and study its effects on the oxidation state of the elements and on the electrical conductivity of the films. A set of films was deposited on alumina substrate by spray pyrolysis. The lithium to nickel ratio in the sprayed solution, 0, 20, 40, and 60 at.%, determined the amount of lithium incorporated into the films. The lithium concentration was obtained by combined energy recoil detection analysis and Rutherford backscattering. The ratios of lithium to nickel atoms incorporated in the films were 0, 12.9, 27.9, and 46.9%, respectively. These results were confirmed by x-ray photoemission spectroscopy, which was also used to analyze the oxidation state of the atomic species in the samples. When the electrical conductivity of selected samples was studied as a function of temperature in the range 50-450 K, kinked-linear behavior was observed; this was attributed to different conducting mechanisms activated by temperature.

  18. Size Control of ZnS Nanoparticles by Electro-Spray Deposition Method

    NASA Astrophysics Data System (ADS)

    Doe, Takahiro; Ishikawa, Yasuaki; Horita, Masahiro; Nishida, Takashi; Uraoka, Yukiharu

    2012-03-01

    Zinc sulfide (ZnS) semiconductor nanoparticles were prepared by electro-spray deposition (ESD) method. ESD method is a particle preparation process via the spray pyrolysis route, in which droplets are generated at the nozzle tip in combination with the evaporation of the solvent in the droplets. We fabricated nanoparticles whose sizes were controlled to the single-digit nanometer scale through precise control of the applied voltage and nozzle tip diameter. We successfully obtained nanoparticles whose sizes were 9.7 nm on average and with 3.1 nm full-width half-maximum of the distribution after optimizing the nozzle tip diameter and the applied voltage. We also confirmed that the obtained nanoparticles had the wurtzite structure of ZnS, and the inside consisted of a single crystal phase according to the X-ray diffraction measurements and the high-resolution transmission electron microscope images.

  19. Smokeless pyrolysis furnace with micro-ramped temperature controlled by water-spray

    SciTech Connect

    Koptis, R.A.; Heran, R.F.

    1990-11-20

    This patent describes an improvement in a pyrolysis furnace. It comprises: a main chamber, a main burner to directly heat air ducted into the chamber, a throat near the top of the main chamber through which throat organic vapor volatilized by pyrolysis of burnables leaves the main chamber, the throat having an area, and the main chamber having a volume which are related such that their ratio is always greater than the critical vent number 0.0003/ft, an afterburner chamber provided with an afterburner to incinerate the organic vapor downstream of the throat, a single temperature sensing means (TC) located within the main chamber to sense the temperature of gases above the metal parts within the chamber, and, an exhaust stack through which incinerated vapor is vented.

  20. The investigation of spray pyrolysis grown CdS thin films doped with flourine atoms

    NASA Astrophysics Data System (ADS)

    Y?lmaz, Salih

    2015-12-01

    Undoped and F-doped CdS thin films were succesfully grown on the glass substrates by the spray prolysis method. X-ray diffraction results showed that all the samples had hexagonal wurtzite structure with the (1 0 1) preferred orientation. It was found from scanning electron microscopy that an increase in the grain size was observed after F-doping. The band gap value of CdS thin films increased from 2.38 eV to 2.42 eV with the increase of F concentration from 0 to 6 at.%. The intensity of room temperature photoluminescence spectrum of undoped CdS thin films enhanced with the increment of F-doping amount that is related to the increase of point defects formed by the flourine atoms. Electrical measurements showed that the carrier concentration increased from 1.93 1012 cm-3 to 7.62 1012 cm-3 when CdS thin films were doped with 2 at.% F. However, further increase in F amount up to 6 at.% caused a decrease in the carrier concentration. On the other hand, resistivity value first decreased from 1.26 105 ? cm to 8.54 104 ? cm with the increase of F-doping up to 2 at.% and then increased to 1.65 105 ? cm for 6 at.% F-doping. It can be concluded that 2 at.% F-doped CdS thin films exhibited the best electrical and optical properties, which is suitable for the application of thin film solar cells.

  1. Fabrication of Cu(In,Ga)(S,Se)2 thin film solar cells via spray pyrolysis of thiourea and 1-methylthiourea-based aqueous precursor solution

    NASA Astrophysics Data System (ADS)

    Kurihara, Masaaki; Septina, Wilman; Hirano, Toshiyuki; Nakajima, Yasuhiro; Harada, Takashi; Ikeda, Shigeru

    2015-09-01

    A detailed process of fabricating Cu(In,Ga)(S,Se)2 via the spray pyrolysis of a thiourea-based precursor solution followed by selenization is reported. The optimization of the selenization condition for the fabrication of the Cu(In,Ga)(S,Se)2 film led to a conversion efficiency of 7.8% for the Cu(In,Ga)(S,Se)2-based device. We also showed that 1-methylthiourea was a more suitable sulfur source for the spray pyrolysis technique, resulting in a conversion efficiency of 8.7% (VOC = 0.52 V, JSC = 31 mA cm-2, and FF = 0.54) without any antireflection coating.

  2. Influences of alcoholic solvents on spray pyrolysis deposition of TiO2 blocking layer films for solid-state dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Jiang, Changyun; Koh, Wei Lin; Leung, Man Yin; Hong, Wei; Li, Yuning; Zhang, Jie

    2013-02-01

    Influences of alcoholic solvents for titanium diisopropoxide bis(acetylacetonate) (TPA) precursor solutions on the spray pyrolysis deposited TiO2 films and the photovoltaic performance of the solid-state dye-sensitized solar cells (SDSCs) using these TiO2 films as the blocking layers were investigated. Smooth TiO2 films were obtained by spray pyrolysis deposition of a TPA solution in isopropanol (IPA) at a relatively low temperature of 260 °C. On the other hand, when ethanol was used as solvent, the TiO2 films fabricated at the same temperature showed much rougher surfaces with many pinholes. Our results showed that ethanol reacts with TPA to form titanium diethoxide bis(acetylacetonate) (TEA), which requires a higher thermal decomposition temperature than that of TPA. SDSCs with TiO2 blocking layer films fabricated using a TPA solution in IPA showed higher power conversion efficiencies with smaller variations.

  3. Metal-insulator transition characteristics of vanadium dioxide thin films synthesized by ultrasonic nebulized spray pyrolysis of an aqueous combustion mixture

    NASA Astrophysics Data System (ADS)

    Bharathi, R.; Naorem, Rameshwari; Umarji, A. M.

    2015-08-01

    We report the synthesis of high quality vanadium dioxide (VO2) thin films by a novel spray pyrolysis technique, namely ultrasonic nebulized spray pyrolysis of aqueous combustion mixture (UNSPACM). This simple and cost effective two step process involves synthesis of a V2O5 film on an LaAlO3 substrate followed by a controlled reduction to form single phase VO2. The formation of M1 phase (P21/c) is confirmed by Raman spectroscopic studies. A thermally activated metal-insulator transition (MIT) was observed at 61 ^\\circ C, where the resistivity changes by four orders of magnitude. Activation energies for the low conduction phase and the high conduction phase were obtained from temperature variable resistance measurements. The infrared spectra also show a dramatic change in reflectance from 13% to over 90% in the wavelength range of 7-15 μ m. This indicates the suitability of the films for optical switching applications at infrared frequencies.

  4. Elaboration of Ti{sub 0.5}Pb{sub 0.5}Sr{sub 2}CaCu{sub 2}O{sub x} superconducting phases by an ultrasonic spray-pyrolysis process

    SciTech Connect

    Abraham, R.; Guenard, F.; Lebbou, K.; Trosset, S.; Cohen-Adad, M.T.; Jorda, J.L.; Couach, M.

    1998-02-01

    An ultrasonic spray-pyrolysis process has been used to prepare a homogeneous T{sub 10.5}Pb{sub 0.5}Sr{sub 2}CaCu{sub 2}O{sub x} high-temperature superconductor. Depending on experimental conditions, the grain morphology changes from platelet to cauliflower-like, contrary to the three copper layers series. The (Tl/Pb)-Sr-1212 phase has remarkable stability and does not decompose before melting. The critical temperature onset, about 80 K, is similar to that for samples prepared by the usual sintering methods.

  5. Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Ortel, Marlis; Balster, Torsten; Wagner, Veit

    2013-12-01

    Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360 °C contained zinc oxynitrides, CO3, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500 °C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140 °C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4 × 1017 eV-1 cm-3 due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm2/V s, the subthreshold slope was 0.3 V dec-1, and an on-set close to the ideal value of 0 V was achieved.

  6. Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis

    SciTech Connect

    Ortel, Marlis; Balster, Torsten; Wagner, Veit

    2013-12-21

    Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360?C contained zinc oxynitrides, CO{sub 3}, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500?C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140?C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4??10{sup 17}?eV{sup ?1}?cm{sup ?3} due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm{sup 2}/V s, the subthreshold slope was 0.3 V dec{sup ?1}, and an on-set close to the ideal value of 0?V was achieved.

  7. Spray pyrolysis growth of a high figure of merit, nano-crystalline, p-type transparent conducting material at low temperature

    NASA Astrophysics Data System (ADS)

    Farrell, L.; Norton, E.; O'Dowd, B. J.; Caffrey, D.; Shvets, I. V.; Fleischer, K.

    2015-07-01

    In this letter, we demonstrate a low temperature (≈345 °C) growth method for Cu deficient CuCrO2 performed by spray pyrolysis using metal-organic precursors and a simple air blast nozzle. Smooth films were grown on glass substrates with a highest conductivity of 12 S/cm. The most conductive samples retain transparencies above 55% resulting in a figure of merit as high as 350 μS, which is the best performing p-type transparent conducting material grown by solution methods to date. Remarkably, despite the nano-crystallinity of the films, properties comparable with crystalline CuCrO2 are observed. No postannealing of the films is required in contrast to previous reports on crystalline material. The low processing temperature of this method means that the material can be deposited on flexible substrates. As this is a solution based technique, it is more attractive to industry as physical vapour deposition methods are slow and costly in comparison.

  8. Synthesis of hollow cobalt oxide nanopowders by a salt-assisted spray pyrolysis process applying nanoscale Kirkendall diffusion and their electrochemical properties.

    PubMed

    Ju, Hyeon Seok; Cho, Jung Sang; Kim, Jong Hwa; Choi, Yun Ju; Kang, Yun Chan

    2015-12-21

    A new concept for preparing hollow metal oxide nanopowders by salt-assisted spray pyrolysis applying nanoscale Kirkendall diffusion is introduced. The composite powders of metal oxide and indecomposable metal salt are prepared by spray pyrolysis. Post-treatment under a reducing atmosphere and subsequent washing using distilled water produce aggregation-free metal nanopowders. The metal nanopowders are then transformed into metal oxide hollow nanopowders by nanoscale Kirkendall diffusion. Co3O4 hollow nanopowders are prepared as first target materials. A cobalt oxide-NaCl composite powder prepared by spray pyrolysis transforms into several Co3O4 hollow nanopowders by several treatment processes. The discharge capacities of the Co3O4 nanopowders with filled and hollow structures at a current density of 1 A g(-1) for the 150th cycle are 605 and 775 mA h g(-1), respectively. The hollow structure formed by nanoscale Kirkendall diffusion improves the lithium-ion storage properties of Co3O4 nanopowders. PMID:26571144

  9. The characteristic and evaluation method of fast pyrolysis of microalgae to produce syngas.

    PubMed

    Hu, Zhifeng; Ma, Xiaoqian; Li, Longjun

    2013-07-01

    The fast pyrolysis of Chlorella vulgaris was carried out in a quartz tube reactor under different pyrolysis temperature levels. The product fractional yields, gaseous products and the evaluation method based on heating value and energy consumption were analyzed in order to obtain the optimal condition to produce syngas. The results indicated that the higher the pyrolysis temperature level was, the higher the bio-fuel yield was. 900C is the best temperature to obtain the maximum bio-fuel yield (91.09 wt.%). And the highest emission of CO and H2 were achieved under the pyrolysis temperature of 800 and 900C, respectively. According to the evaluation method based on heating value and energy consumption, there was a significant impact on the syngas production under different pyrolysis temperatures. Furthermore, the evaluation method based on energy consumption indicated that 800C was the optimal pyrolysis temperature to produce syngas. PMID:23693148

  10. Fabrication and characterization of n-ZnO:Eu/p-ZnO:(Ag, N) homojunction by spray pyrolysis

    SciTech Connect

    Swapna, R.; Kumar, M.C. Santhosh

    2014-01-01

    Graphical abstract: In this paper authors report the fabrication of ZnO homojunction by the deposition of 2 at.% Eu doped ZnO (n-ZnO:Eu) layer grown over the 4 at.% AgN dual acceptor doped ZnO (p-ZnO:(Ag, N)) layer by spray pyrolysis technique. The as-grown n-type and p-type ZnO films on glass substrates have been characterized by Hall measurements, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), UVvis and luminescence spectroscopy techniques. Hall measurement shows that 4 at.% ZnO:(Ag, N) film exhibits p-type conductivity with high hole concentration of 2.17 10{sup 18} cm{sup ?3} and n-type conductivity is observed in the ZnO:Eu film. The currentvoltage characteristics measured from the two-layer structure show typical rectifying characteristics of pn homojunction with a low turn on voltage of about 1.85 V. IV characteristics of the n-ZnO:Eu/p-ZnO:(Ag, N) homojunction. - Highlights: The n-ZnO:Eu/p-ZnO:(Ag, N) homojunction is fabricated and characterized. Low resistive and stable p-type ZnO films are achieved by dual acceptor-doping. Homojunction with best dual-doped ZnO film shows good rectifying characteristics. The fabricated ZnO homojunction is suitable for optoelectronic devices. - Abstract: In the present study, the authors report the fabrication of ZnO homojunction by the deposition of 2 at.% Eu doped ZnO (n-ZnO:Eu) layer grown over the 4 at.% AgN dual acceptor doped ZnO (p-ZnO:(Ag, N)) layer by spray pyrolysis technique. The as-grown n-type and p-type ZnO films on glass substrates have been characterized by Hall measurements, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), UVvis and luminescence spectroscopy techniques. Hall measurement shows that 4 at.% ZnO:(Ag, N) film exhibits p-type conductivity with high hole concentration of 2.17 10{sup 18} cm{sup ?3} and n-type conductivity is observed in the ZnO:Eu film. The currentvoltage characteristics measured from the two-layer structure show typical rectifying characteristics of pn homojunction with a low turn on voltage of about 1.85 V.

  11. Synthesis and characterization of nano-V2O5 by flame spray pyrolysis, and its cathodic performance in Li-ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Sel, Sinem; Duygulu, Ozgur; Kadiroglu, Umit; Machin, Nesrin E.

    2014-11-01

    Vanadium pentoxide (V2O5) nano-particles have been synthesized by flame spray pyrolysis method to investigate their cathodic performance in Li-ion rechargeable batteries. They were characterized by surface area (Brunauer-Emmett-Teller, BET method), scanning electron microscopy (SEM), transmission electron microscopy-energy dispersive spectrometry (TEM-EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) methods. Spherical, crystalline (orthorhombic) nano-V2O5 particles were produced. The electrochemical tests, including cyclic voltammetry (CV) and ac impedance spectroscopy (IS), were performed to obtain the reversibility and conductivity kinetic parameters. From IS measurements, nano film conductivity was found to be 2.42 10-6 S cm-1, which is 10-fold higher than the commercial micro-particle V2O5 counterparts. From spectra, it was also found that the interfacial resistance became stable after 7200 s. The impedance results indicated that the rate of reaction at the interphase was controlled by both charge transfer and diffusion processes. The cyclic voltammogram showed high reversibility rate and low polarization.

  12. Low-voltage ZnO thin-film transistors based on Y2O3 and Al2O3 high-k dielectrics deposited by spray pyrolysis in air

    NASA Astrophysics Data System (ADS)

    Adamopoulos, George; Thomas, Stuart; Bradley, Donal D. C.; McLachlan, Martyn A.; Anthopoulos, Thomas D.

    2011-03-01

    We report the application of ambient spray pyrolysis for the deposition of high-k polycrystalline Y2O3 and amorphous Al2O3 dielectrics and their use in low-voltage ZnO thin-film transistors. The films are studied by means of atomic force microscopy, UV-visible absorption spectroscopy, impedance spectroscopy, and field-effect measurements. ZnO transistors based on spray pyrolysed Y2O3 and Al2O3 dielectrics show low leakage currents, and hysteresis-free operation with a maximum electron mobility of 34 cm2/V s and current on/off ratio on the order of 105. This work is a significant step toward high-performance oxide electronics manufactured using simple and scalable processing methods.

  13. Yolk-shell structured Gd2O3:Eu(3+) phosphor prepared by spray pyrolysis: the effect of preparation conditions on microstructure and luminescence properties.

    PubMed

    Cho, Jung Sang; Jung, Kyeong Youl; Kang, Yun Chan

    2015-01-14

    Gd2O3:Eu(3+) yolk-shell phosphor powders with high photoluminescence intensity were prepared by spray pyrolysis. Preparation temperature and spray solution concentration were varied to find the optimum process conditions for preparation of Gd2O3:Eu(3+) with yolk-shell structure. The formation mechanism of yolk-shell Gd2O3:Eu(3+) was systematically investigated by observing the microstructures of particles produced under various preparation conditions. The morphological structure of Gd2O3:Eu(3+) powders was clearly dependent on reactor temperature and on the precursor solution concentration. Eventually, pure yolk-shell structured Gd2O3:Eu(3+) powders were obtained for a reaction temperature of 1000 C and concentration of the spray solution below 0.2 M. Also, the yolk-shell structure formed showed high thermal stability, making it possible to maintain the original spherical yolk-shell structure through calcination at high temperatures. As a result, highly crystalline Gd2O3:Eu(3+) phosphor powders having yolk-shell structure and an agglomeration-free spherical shape were successfully synthesized by spray pyrolysis. These phosphor powders were shown to have good photoluminescence characteristics. PMID:25424414

  14. Control of Ag nanoparticle distribution influencing bioactive and antibacterial properties of Ag-doped mesoporous bioactive glass particles prepared by spray pyrolysis.

    PubMed

    Shih, Shao-Ju; Tzeng, Wei-Lung; Jatnika, Rifqi; Shih, Chi-Jen; Borisenko, Konstantin B

    2015-05-01

    Mesoporous bioactive glasses (MBGs) have become important bone implant materials because of their high specific surface area resulting in high bioactivity. Doping MBGs with Ag removes one of the remaining challenges to their applications, namely their lack of intrinsic antibacterial properties. In present work we demonstrate that Ag-doped MBGs can be prepared in one-step spray pyrolysis (SP) process. The SP preparation method offers the advantages of short processing times and continuous production over the sol-gel method previously used to prepare MBGs. Using scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction we demonstrate that the synthesized MBG particles have amorphous structure with nanocrystalline Ag inclusions. The scanning transmission electron microscopy-X-ray energy dispersive spectrometry of cross-sectional samples shows that the distribution of the Ag dopant nanoparticles within MBGs can be controlled by using the appropriate formulation of the precursors. The distribution of the Ag dopant nanoparticles within the MBG particles was found to affect their surface areas, bioactivities and antibacterial properties. Based on the observations, we propose a mechanism describing MBG particle formation and controlling dopant distribution. PMID:25171327

  15. Spray pyrolysis prepared yellow to red color tunable Sr?-xCaxSe:Eu+ phosphors for white LED.

    PubMed

    Chung, Wonkeun; Jung, Hyunchul; Lee, Chang Hun; Kim, Jihyun; Kim, Sung Hyun

    2012-06-01

    The spherical and submicron size of Sr?-xCaxSe:Eu? phosphors were successfully prepared by ultrasonic spray pyrolysis. The phosphors adopted a cubic structure, and the replacement of Sr? with Ca? decreased the lattice parameter. The Sr?-xCaxSe:Eu? showed broad and strong excitation under 420-460 nm blue light, and the emission band could be tuned from 565 to 607 nm by increasing the Ca? ratio in the host lattice. In addition, the doping of Zn? into Sr? or Ca? enhanced the emission intensity with a small red shift due to the change in crystal field strength and nephelauxetic effects. The warm and high CRI of white LED was achieved using blue LED pumped with blending phosphors of 612 nm emitting Ca?.??Zn?.??Se:Eu? and 565 nm emitting YAG. The correlated color temperatures and CRI were 4719.2K, and 86.3, respectively, and an acceptable color variation was also observed at operating currents ranging from 20 to 70 mA. PMID:22714315

  16. Photoluminescence Properties and Morphologies of Submicron-Sized ZnO Crystals Prepared by Ultrasonic Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Htay, Myo Than; Itoh, Minoru; Hashimoto, Yoshio; Ito, Kentaro

    2008-01-01

    Spectral features of the near-band-edge photoluminescence (PL) of submicron-sized ZnO crystals such as nanoplatelets, nanowires, and nanorods grown by an ultrasonic spray pyrolysis (USP) technique were investigated. The measurements of time-integrated and time-resolved PL spectra were performed in the temperature range of 8-300 K under various excitation densities by using the fourth harmonics (4.66 eV) of a Nd:YAG laser. Exciton-related emission bands were clearly observed in the ZnO crystals having different morphologies. In nanoplatelets, an emission band originating from radiative recombination of donor-acceptor pairs was also found at around 3.17 eV, indicating the existence of acceptor centers. The binding energies of donor and acceptor were about 53 and 200 meV, respectively. In nanowires, the intensity of an emission band peaking at 3.32 eV obeyed a quadratic dependency on the density of excitation. This fact shows that an inelastic exciton-exciton scattering process is efficient in the nanowires because of high crystal quality.

  17. The effect of solution concentration on the physical and electrochemical properties of vanadium oxide films deposited by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Mousavi, M.; Kompany, A.; Shahtahmasebi, N.; Bagheri-Mohagheghi, M. M.

    2013-10-01

    Vanadium oxide thin films were prepared on glass substrates by using the spray pyrolysis technique. The effect of solution concentration (0.1 M, 0.2 M and 0.3 M) on the nanostructural, electrical, optical, and electrochromic properties of deposited films were investigated using X-ray diffraction, scanning electron microscopy, UV—vis spectroscopy, and cyclic volta-metrics. The X-ray diffraction shows that only the sample at 0.1 M has a single β-V2O5 phase and the others have mixed phases of vanadium oxide. The lowest sheet resistance was obtained for the samples prepared at 0.3 M solution. It was also found that the optical transparency of the samples changes from 70% to 35% and the optical band gap of the samples was in the range of 2.20 to 2.41 eV, depending on the morality of solution. The cycle voltammogram shows that the sample prepared at 0.3 M has one-step electerochoromic but the other samples have two-step electerochoromic. The results show a correlation between the cycle voltammogram and the physical properties of the films.

  18. Spray pyrolysis synthesis of MAl 2O 4:Eu 2+ (M=Ba, Sr) phosphor for UV LED excitation

    NASA Astrophysics Data System (ADS)

    Chung, Wonkeun; Jeong Yu, Hong; Hee Park, Sun; Chun, Byung-Hee; Kim, Jihyun; Hyun Kim, Sung

    2011-07-01

    The UV excited green emitting Eu 2+-activated BaAl 2O 4 and SrAl 2O 4 phosphors were prepared by ultrasonic spray pyrolysis at low temperature. The morphologies of phosphors were spherical and 1 ?m size with non-aggregation. The BaAl 2O 4:Eu 2+ and SrAl 2O 4:Eu 2+ were efficiently excited under UV range from 320 to 370 nm, and exhibited broad band emission at about 500 and 520 nm, respectively, corresponding to the 5d-4f transition of Eu 2+. The detailed properties of crystal structure and luminescence behaviors were discussed by measurements of X-ray diffraction and photoluminescence. Phosphor conversion LEDs were fabricated by combining GaN-based 380 nm emitting UV LED as an optical pumping source with the prepared phosphors. The BaAl 2O 4:Eu 2+ phosphor LEDs showed the CIE coordinate of (0.171, 0.432) in bluish-green emission, and SrAl 2O 4:Eu 2+ phosphor LEDs showed that of (0.224, 0.518) in green emission.

  19. Growth of tin oxide thin films composed of nanoparticles on hydrophilic and hydrophobic glass substrates by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Paloly, Abdul Rasheed; Satheesh, M.; Martínez-Tomás, M. Carmen; Muñoz-Sanjosé, Vicente; Rajappan Achary, Sreekumar; Bushiri, M. Junaid

    2015-12-01

    In this paper, we have demonstrated the growth of tin oxide (SnO2) thin films composed of nanoparticles on hydrophobic (siliconized) and hydrophilic (non-siliconized) glass substrates by using the spray pyrolysis technique. X-ray diffraction (XRD) analysis confirmed the formation of SnO2 thin films with tetragonal rutile-phase structure. Average particle size of nanoparticles was determined to be in the range of 3-4 nm measured from the front view images obtained by a field emission gun scanning electron microscope (FESEM), while the size of nanoparticle clusters, when present, were in the range of 11-20 nm. Surface morphology of SnO2 films grown over hydrophobic substrates revealed larger isolated particles which are less crowded compared to the highly crowded and agglomerated smaller particles in films on hydrophilic substrates. Blue shift in the band gap is observed in samples in which the average particle size is slightly larger than the exciton Bohr radius. Photoluminescence (PL) analysis of samples grown over hydrophobic substrates exhibited an intense defect level emission and a weak near band edge emission. The enhanced visible emission from these SnO2 thin films is attributed to lattice defects formed during the film growth due to the mismatch between the film and the hydrophobic substrate surface.

  20. Transparent and conductive Al/F and In co-doped ZnO thin films deposited by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hadri, A.; Taibi, M.; El hat, A.; Mzerd, A.

    2016-02-01

    In doped ZnO (IZO), In-Al co-doped ZnO (IAZO) and In-F co-doped ZnO (IFZO) were deposited on glass substrates at 350 °C by spray pyrolysis technique. The structural, optical and electrical properties of as-deposited thin films were investigated and compared. A polycrystalline and (002) oriented wurtzite crystal structure was confirmed by X-ray patterns for all films; and the full width at half -maximum (FWHM) of (002) diffraction peak increased after co-doping. The investigation of the optical properties was performed using Uv-vis spectroscopy. The average transmittances of all the films were between 70 and 85%. Hall Effect measurements showed that the electrical conductivity of co-doped films increased as compared with IZO thin film. The highest conductivity of about 16.39 Ω-1 cm-1 was obtained for as-deposited IFZO thin film. In addition, the thin films were annealed at 350 °C for two hour under Ar atmosphere and their optical, electrical properties and the associated photoluminescence (PL) responses of selected films were analysed. After annealing, the electrical conductivity of all thin films was improved and the optical transmittance remained above 70%. Room temperature PL revealed that the annealed IAZO thin film had a strong green emission than that of IZO film.

  1. Spray pyrolysis derived ZnMgO:In thin films: Investigation of the structural, optical and electrical properties

    NASA Astrophysics Data System (ADS)

    Yan, Wei; Tan, Jin; Zhang, Wei; Liang, Yujun; Feng, Shan; Lei, Xinrong; Wang, Hongquan

    2013-08-01

    Zn1-xMgxO:In films were deposited on quartz substrates via ultrasonic spray pyrolysis (USP). By tuning the molar ratio of Zn and Mg sources, the tunable band gap in ZnMgO:In films were realized. The obtained films exhibited wurtzite crystal structure with a preferential c-axis orientation. Larger grain size was obtained with increasing the Mg introduction. Photoluminescence (PL) indicated that the peaks of near-band-edge (NBE) emission appeared as a blue-shift from 378 nm to 370 nm, labeled as x value increase from 0 to 0.15. Optical band gap (Eg) calculated from the absorption edge further confirmed the blue-shift phenomenon due to the Mg substitution for Zn lattice sites. The average transmittance was about 90% in the visible wavelength region (400-800 nm). The increasing resistivity from 6.70 × 10-3 Ω cm to 2.14 × 10-2 Ω cm and decreasing mobility from 24.7 cm2 V-1 S-1 to 6.46 cm2 V-1 S-1 were observed.

  2. Electrical, optical, and structural characteristics of Al2O3 thin films prepared by pulsed ultrasonic sprayed pyrolysis

    NASA Astrophysics Data System (ADS)

    Carmona-Tellez, S.; Guzman-Mendoza, J.; Aguilar-Frutis, M.; Alarcon-Flores, G.; Garcia-Hipolito, M.; Canseco, M. A.; Falcony, C.

    2008-02-01

    The optical, structural, and electrical characteristics of aluminum oxide thin films deposited by pulsed ultrasonic sprayed pyrolysis are reported. The films are deposited on crystalline silicon at temperatures from 400to550C using a chemical solution of aluminum acetylacetonate, as source of aluminum, and N, N-dimethylformamide, as solvent. A H2O-NH4OH mist is supplied simultaneously during deposition to improve the films' properties. The results showed that the properties of the as deposited films depended strongly on the number of pulses used and on the substrate temperature. The thickness of the films is under 300 and the best films' properties showed an index of refraction close to 1.6 and a root mean square surface roughness of about 7.5 in average. Infrared spectroscopy shows that SiO2 is observed at the interface with silicon of the Al2O3 films and seemed to play, as expected, a dramatic role in the electrical characteristics of the interface. Films with a dielectric constant higher than 8 and an interface trap density at midgap in the 1010eV-1cm-2 range are obtained. Films deposited with three pulses and at 550C are able to stand an electric field up to 4MV /cm.

  3. Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Gven, Turgut; Adem, Koyi?it; Erdal, Snmez

    2015-10-01

    The Pr and Ta separately doped FTO (10 at.% F incorporated SnO2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.

  4. Electrical and morphological properties of conducting layers formed from the silver-glass composite conducting powders prepared by spray pyrolysis.

    PubMed

    Jung, D S; Koo, H Y; Kang, Y C

    2010-03-01

    Ag-glass composite powders with various glass contents and excellent conducting properties were prepared by spray pyrolysis. Irrespective of the glass content, all the prepared powders were found to comprise spherical particles with nonaggregation characteristics. The crystal structure of the powder particles resembled that of pure Ag particles, irrespective of the glass content. Conducting layers formed from pure Ag did not melt even when sintered at 400 degrees C. On the other hand, conducting layers formed from composite powders containing 3 and 5 wt% glass melted when sintered at 400 degrees C. The optimum glass content of the composite powders was 3 wt% at sintering temperatures of 400 and 450 degrees C. However, the optimum glass content decreased to 1 wt% when the sintering temperature was increased to 550 degrees C. The lowest specific resistances of the conducting layers formed from the composite powders were 5.3 and 2.3 microohms-cm at sintering temperatures of 400 and 550 degrees C, respectively. PMID:20036371

  5. Ni-SiO? catalysts for the carbon dioxide reforming of methane: varying support properties by flame spray pyrolysis.

    PubMed

    Lovell, Emma C; Scott, Jason; Amal, Rose

    2015-01-01

    Silica particles were prepared by flame spray pyrolysis (FSP) as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min) during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM) was probed. Increasing the precursor feed rate: (i) progressively lowered the silica surface area from ?340 m2/g to ?240 m2/g; (ii) altered the silanol groups on the silica surface; and (iii) introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt %) nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics. PMID:25774491

  6. Nickel-induced microwheel-like surface morphological evolution of ZnO thin films by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Tarwal, N. L.; Shinde, P. S.; Oh, Y. W.; Cerc Koroec, Romana; Patil, P. S.

    2012-11-01

    Nickel-zinc oxide (Ni-ZnO) thin films were deposited onto glass and tin-doped indium oxide-coated glass substrates by using a pneumatic spray pyrolysis technique at 450 C from aqueous solutions of zinc acetate and nickel acetate precursors. The effect of nickel doping on structural, morphological and optical properties of the ZnO thin films has been studied. The X-ray diffraction patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. Ni-ZnO films with appropriate nickel doping revealed the occurrence of novel wheel-like surface morphology. The absorption edge of the Ni-ZnO films showed a red shift, meaning that the optical band gap energy decreases as the nickel doping concentration increases. A growth model is developed and proposed for the novel wheel-like morphology. All the thin films exhibited room-temperature photoluminescence. Pure ZnO and Ni-ZnO thin films were tested for their photoelectrochemical performance in 0.5 M Na2SO4 electrolyte solution. The values of fill factor and open circuit voltage were improved for the Ni-ZnO thin films.

  7. High-Temperature Jet Spray Reactor for the Preparation of Rare Earth Oxides by Pyrolysis: Computer Simulation

    NASA Astrophysics Data System (ADS)

    Zhao, Qiu-yue; Lv, Chao; Zhang, Zi-mu; Dou, Zhi-he; Zhang, Ting-an; Liu, Yan; Lv, Guo-zhi

    2014-09-01

    A new type of high-temperature jet spray pyrolysis (SP) reactor is investigated in this article as part of studies on the preparation of rare earth oxides at Northeastern University (NEU), Shenyang, China. The jet spray reactor examined here is a horizontal, tubular reactor conveying the hot products of the combustion of methane and oxygen with a converging-diverging jet section in an arrangement that provides for inspiration of LaCl3 solution to pyrolyze to La2O3 with the hot gas. The present article is concerned with a computer simulation using a computational fluid dynamic model to develop the velocity, temperature, and pressure profiles in the jet reactor since direct measurement is difficult. The article includes brief comments on a room-temperature model designed to examine the flow characteristics of the jet SP reactor. It was found that the velocity decreased at first, and then it increased near the jet throat. The highest velocity occurred at the throat of jet SP reactor where the LaCl3 enters the unit. Along the reactor axis, the temperature decreases with distance from the gas inlet. The lowest temperature zone was near the wall before the throat of the reactor due to wall heat losses. The temperature was estimated to be close to 1700 K at the throat of the reactor, and it was about 1300 K toward the exit of the reactor. It was shown that a reaction would take place mainly in the throat and in the vicinity of first contact between gas and induced spray. A negative pressure was produced as gas passes through the converging-diverging throat of the jet SP reactor that causes the LaCl3 solution to enter the throat of the reactor. While the investigations of this type of reactor are at an early stage, the results look promising. NEU continues to investigate this approach for the preparation of La2O3 based on high-temperature testwork and physical modeling techniques.

  8. High-Temperature Jet Spray Reactor for the Preparation of Rare Earth Oxides by Pyrolysis: Computer Simulation

    NASA Astrophysics Data System (ADS)

    Zhao, Qiu-yue; Lv, Chao; Zhang, Zi-mu; Dou, Zhi-he; Zhang, Ting-an; Liu, Yan; Lv, Guo-zhi

    2014-08-01

    A new type of high-temperature jet spray pyrolysis (SP) reactor is investigated in this article as part of studies on the preparation of rare earth oxides at Northeastern University (NEU), Shenyang, China. The jet spray reactor examined here is a horizontal, tubular reactor conveying the hot products of the combustion of methane and oxygen with a converging-diverging jet section in an arrangement that provides for inspiration of LaCl3 solution to pyrolyze to La2O3 with the hot gas. The present article is concerned with a computer simulation using a computational fluid dynamic model to develop the velocity, temperature, and pressure profiles in the jet reactor since direct measurement is difficult. The article includes brief comments on a room-temperature model designed to examine the flow characteristics of the jet SP reactor. It was found that the velocity decreased at first, and then it increased near the jet throat. The highest velocity occurred at the throat of jet SP reactor where the LaCl3 enters the unit. Along the reactor axis, the temperature decreases with distance from the gas inlet. The lowest temperature zone was near the wall before the throat of the reactor due to wall heat losses. The temperature was estimated to be close to 1700 K at the throat of the reactor, and it was about 1300 K toward the exit of the reactor. It was shown that a reaction would take place mainly in the throat and in the vicinity of first contact between gas and induced spray. A negative pressure was produced as gas passes through the converging-diverging throat of the jet SP reactor that causes the LaCl3 solution to enter the throat of the reactor. While the investigations of this type of reactor are at an early stage, the results look promising. NEU continues to investigate this approach for the preparation of La2O3 based on high-temperature testwork and physical modeling techniques.

  9. Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS.

    PubMed

    Antonakou, E V; Kalogiannis, K G; Stephanidis, S D; Triantafyllidis, K S; Lappas, A A; Achilias, D S

    2014-12-01

    Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds. PMID:25246066

  10. Investigations on structural, vibrational, morphological and optical properties of CdS and CdS/Co films by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Aksay, S.; Polat, M.; zer, T.; Kse, S.; Grbz, G.

    2011-09-01

    CdS and CdS/Co films have been deposited on glass substrates by an ultrasonic spray pyrolysis method. The effects of Co incorporation on the structural, optical, morphological, elemental and vibrational properties of these films were investigated. XRD analysis confirmed the hexagonal wurtzite structure of all films and had no impurity phase. While CdS film has (0 0 2) as the preferred orientation, CdS/Co films have (1 1 0) as the preferred orientation. The direct optical band gap was found to decrease from 2.42 to 2.39 eV by Co incorporation. The decrease of the direct energy gaps by increasing Co contents is mainly due to the sp-d exchange interaction between the localized d-electrons of Co2+ ions and band electrons of CdS. After the optical investigations, it was seen that the transmittance of CdS films decreased by Co content. The Raman measurements revealed two peaks corresponding to the 1LO and 2LO modes of hexagonal CdS. The vibrational modes of Cd-S were obtained in the wavenumber range (590-715 cm-1) using Fourier transform infrared spectroscopy (FTIR). The elemental analysis of the film was done by energy dispersive X-ray spectrometry.

  11. Growth and characterization of Cu3SnS4 thin films by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Chalapathi, U.; Kishore Kumar, Y. B.; Uthanna, S.; Raja, V. Sundara

    2012-06-01

    Copper tin sulphide (Cu3SnS4), a promising solar cell absorber layer, was successfully grown onto soda-lime glass substrates by sulfurization of spray deposited films at a substrate temperature of 400 C. The sulfurization was carried out at a temperature of 550 C for 1 hour in 1 mbar pressure. The films were analyzed by studying their structural, morphological, optical and electrical properties. XRD studies revealed that the sulfurized films are polycrystalline Cu3SnS4 with orthorhombic structure. The films are slightly Cu-poor and Sn-rich. The direct optical band gap was found to be 1.80 eV. The room temperature electrical resistivity of the films was found to be 3.50 10-4 ?-cm.

  12. Spray pyrolysis deposition of Cu-ZnO and Zn-SnO2 solar cells

    NASA Astrophysics Data System (ADS)

    Khelfane, A.; Tarzalt, H.; Sebboua, B.; Zerrouki, H.; Kesri, N.

    2015-12-01

    Large-gap metal oxides, such as titanium, tin, and zinc oxides, have attracted great interest because of their remarkable potential in dye-sensitized solar cells (DSSC) and their low cost and simple preparation procedure. In this work, we investigated several Zn-SnO2 and Cu-ZnO thin films that were sprayed under different experimental conditions. We varied [Zn/[Sn] and [Cu/[Zn] ratios, calculated on atomic percent in the starting solution. We report some structural results of the films using X-ray diffraction. Optical reflection and transmission spectra investigated by an UV/VIS/NIR spectrophotometer permit the determination of optical constants. The direct band gap was deduced from the photon energy dependence of the absorption coefficient.

  13. Spray drift reduction test method correlation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ASTM Standard E609 Terminology Relating to Pesticides defines drift as “The physical movement of an agrochemical through the air at the time of application or soon thereafter to any non or off target site.” Since there are many commercial tank mix adjuvants designed to reduce spray drift, ASTM esta...

  14. Optical properties of ZnMgO films grown by spray pyrolysis and their application to UV photodetection

    NASA Astrophysics Data System (ADS)

    Lopez-Ponce, M.; Hierro, A.; Marn-Borrs, V.; Tabares, G.; Kurtz, A.; Albert, S.; Agouram, S.; Muoz-Sanjos, V.; Muoz, E.; Ulloa, J. M.

    2015-10-01

    This work presents a comprehensive optical characterization of Zn1-xMgxO thin films grown by spray pyrolysis (SP). Absorption measurements show the high potential of this technique to tune the bandgap from 3.30 to 4.11 eV by changing the Mg acetate content in the precursor solution, leading to a change of the Mg-content ranging from 0 up to 35%, as measured by transmission electron microscopy-energy dispersive x-ray spectroscopy. The optical emission of the films obtained by cathodoluminescence and photoluminescence spectroscopy shows a blue shift of the peak position from 3.26 to 3.89 eV with increasing Mg incorporation, with a clear excitonic contribution even at high Mg contents. The linewidth broadening of the absorption and emission spectra as well as the magnitude of the observed Stokes shift are found to significantly increase with the Mg content. This is shown to be related to both potential fluctuations induced by pure statistical alloy disorder and the presence of a tail of band states, the latter dominating for medium Mg contents. Finally, metal-semiconductor-metal photodiodes were fabricated showing a high sensitivity and a blue shift in the cut-off energy from 3.32 to 4.02 eV, i.e., down to 308 nm. The photodiodes present large UV/dark contrast ratios (102 - 107), indicating the viability of SP as a growth technique to fabricate low cost (Zn, Mg)O-based UV photodetectors reaching short wavelengths.

  15. Dual acceptor doping and aging effect of p-ZnO:(Na, N) nanorod thin films by spray pyrolysis

    SciTech Connect

    Swapna, R. E-mail: santhoshmc@nitt.edu; Amiruddin, R. E-mail: santhoshmc@nitt.edu; Santhosh Kumar, M. C. E-mail: santhoshmc@nitt.edu

    2014-01-28

    An attempt has been made to realize p-type ZnO by dual acceptor doping (Na-N) into ZnO thin films. Na and N doped ZnO thin films of different concentrations (0 to 8 at.%) have been grown by spray pyrolysis at 623 K. The grown films on glass substrate have been characterized by X-ray diffraction (XRD), Hall measurement, UV-Vis spectrophotometer, Photoluminescence (PL) and Energy dispersive spectroscopy (EDS) to validate the p-type conduction. The surface morphology and roughness of the ZnO:(Na, N) films are studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Hall measurement shows that all the films exhibit p-type conductivity except for 0 at.% Na-N doped ZnO film. The obtained resistivity (5.60×10{sup −2} Ω cm) and hole concentration (3.15×10{sup 18} cm{sup −3}) for the best dual acceptor doped film is 6 at.%. It has been predicted that (Na{sub Zn}−N{sub O}) acceptor complex is responsible for the p-type conduction. The p-type conductivity of the ZnO:(Na, N) films is stable even after 6 months. The crystallinity of the films has been studied by XRD. Energy dispersive spectroscopy (EDS) confirms the presence of Na and N in 6 at.% ZnO:(Na, N) film. Photoluminescence (PL) spectra of ZnO:(Na, N) films show NBE and deep level emissions in the UV and visible regions, respectively. The ZnO:(Na, N) films exhibit a high transmittance about 90% in the visible region.

  16. Influences of alcoholic solvents on spray pyrolysis deposition of TiO{sub 2} blocking layer films for solid-state dye-sensitized solar cells

    SciTech Connect

    Jiang, Changyun; Koh, Wei Lin; Leung, Man Yin; Hong, Wei; Li, Yuning; Department of Chemical Engineering and Waterloo Institute for Nanotechnology , University of Waterloo, 200 University Ave West ON, Waterloo, Canada N2L 3G1 ; Zhang, Jie

    2013-02-15

    Influences of alcoholic solvents for titanium diisopropoxide bis(acetylacetonate) (TPA) precursor solutions on the spray pyrolysis deposited TiO{sub 2} films and the photovoltaic performance of the solid-state dye-sensitized solar cells (SDSCs) using these TiO{sub 2} films as the blocking layers were investigated. Smooth TiO{sub 2} films were obtained by spray pyrolysis deposition of a TPA solution in isopropanol (IPA) at a relatively low temperature of 260 Degree-Sign C. On the other hand, when ethanol was used as solvent, the TiO{sub 2} films fabricated at the same temperature showed much rougher surfaces with many pinholes. Our results showed that ethanol reacts with TPA to form titanium diethoxide bis(acetylacetonate) (TEA), which requires a higher thermal decomposition temperature than that of TPA. SDSCs with TiO{sub 2} blocking layer films fabricated using a TPA solution in IPA showed higher power conversion efficiencies with smaller variations. - Graphical abstract: Alcoholic solvents used for the TiO{sub 2} precursor play a critical role in determining the surface morphology of blocking layers and thus the photovoltaic performance of the SDSCs. Highlights: Black-Right-Pointing-Pointer Solvent influences morphology of spray pyrolysis deposited TiO{sub 2} blocking layer. Black-Right-Pointing-Pointer Ethanol reacts with TPA, resulting poor quality of blocking layer. Black-Right-Pointing-Pointer Isopropanol is better than ethanol for obtaining smooth blocking layer. Black-Right-Pointing-Pointer SDSC with blocking layer made with isopropanol showed better performance.

  17. Influence of Boron doping on the structural, optical and electrical properties of CdO thin films by spray pyrolysis technique

    SciTech Connect

    Velusamy, P. Babu, R. Ramesh; Ramamurthi, K.

    2014-04-24

    Cadmium oxide and Boron (B) doped Cadmium oxide thin films were deposited using spray pyrolysis technique. The structural, morphological, electrical and optical properties of undoped and B doped CdO films are analyzed by varying the dopant concentration in the solution. The structural study shows the polycrystalline nature and cubic structure of undoped and B doped CdO thin films. Surface morphological study reveals that the grains are spherical in shape. Optical and electrical studies showed n-type semiconducting nature and optical band gap of 2.44 eV of deposited thin films.

  18. Method and apparatus for spraying molten materials

    DOEpatents

    Glovan, R.J.; Tierney, J.C.; McLean, L.L.; Johnson, L.L.; Nelson, G.L.; Lee, Y.M.

    1996-06-25

    A metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments. 12 figs.

  19. Method of producing thermally sprayed metallic coating

    SciTech Connect

    Byrnes, Larry Edward; Kramer, Martin Stephen; Neiser, Richard A.

    2003-08-26

    The cylinder walls of light metal engine blocks are thermally spray coated with a ferrous-based coating using an HVOF device. A ferrous-based wire is fed to the HVOF device to locate a tip end of the wire in a high temperature zone of the device. Jet flows of oxygen and gaseous fuel are fed to the high temperature zone and are combusted to generate heat to melt the tip end. The oxygen is oversupplied in relation to the gaseous fuel. The excess oxygen reacts with and burns a fraction of the ferrous-based feed wire in an exothermic reaction to generate substantial supplemental heat to the HVOF device. The molten/combusted metal is sprayed by the device onto the walls of the cylinder by the jet flow of gases.

  20. Method and apparatus for spraying molten materials

    DOEpatents

    Glovan, Ronald J. (Butte, MT); Tierney, John C. (Butte, MT); McLean, Leroy L. (Butte, MT); Johnson, Lawrence L. (Butte, MT); Nelson, Gordon L. (Butte, MT); Lee, Ying-Ming (Butte, MT)

    1996-01-01

    A metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments.

  1. Synthesis of Zn1-x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application

    NASA Astrophysics Data System (ADS)

    Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime

    2015-10-01

    Zn1-x Co x Al2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE L*a*b* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250C to evaluate the color performance after a decoration process.

  2. Synthesis of Zn1- x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application

    NASA Astrophysics Data System (ADS)

    Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime

    2016-01-01

    Zn1- x Co x Al2O4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200°C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE L*a*b* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250°C to evaluate the color performance after a decoration process.

  3. One-Pot Synthesis of CoSex -rGO Composite Powders by Spray Pyrolysis and Their Application as Anode Material for Sodium-Ion Batteries.

    PubMed

    Park, Gi Dae; Kang, Yun Chan

    2016-03-14

    A simple one-pot synthesis of metal selenide/reduced graphene oxide (rGO) composite powders for application as anode materials in sodium-ion batteries was developed. The detailed mechanism of formation of the CoSex -rGO composite powders that were selected as the first target material in the spray pyrolysis process was studied. The crumple-structured CoSex -rGO composite powders prepared by spray pyrolysis at 800 °C had a crystal structure consisting mainly of Co0.85 Se with a minor phase of CoSe2 . The bare CoSex powders prepared for comparison had a spherical shape and hollow structure. The discharge capacities of the CoSex -rGO composite and bare CoSex powders in the 50th cycle at a constant current density of 0.3 A g(-1) were 420 and 215 mA h g(-1) , respectively, and their capacity retentions measured from the second cycle were 80 and 46 %, respectively. The high structural stability of the CoSex -rGO composite powders for repeated sodium-ion charge and discharge processes resulted in superior sodium-ion storage properties compared to those of the bare CoSex powders. PMID:26864320

  4. Effect of different dopant elements (Al, Mg and Ni) on microstructural, optical and electrochemical properties of ZnO thin films deposited by spray pyrolysis (SP)

    NASA Astrophysics Data System (ADS)

    Benzarouk, Hayet; Drici, Abdelaziz; Mekhnache, Mounira; Amara, Abdelaziz; Guerioune, Mouhamed; Bernde, Jean Christian; Bendjffal, Hacen

    2012-09-01

    In the present work we studied the influence of the dopant elements and concentration on the microstructural and electrochemical properties of ZnO thin films deposited by spray pyrolysis. Transparent conductive thin films of zinc oxide (ZnO) were prepared by the spray pyrolysis process using an aqueous solution of zinc acetate dehydrate [Zn(CH3COO)22H2O] on soda glass substrate heated at 400 5 C. AlCl3, MgCl2 and NiCl2 were used as dopant. The effect of doping percentage (2-4%) has been investigated. Afterwards the samples were thermally annealed in an ambient air during one hour at 500 C. X-ray diffraction showed that films have a wurtzite structure with a preferential orientation along the (0 0 2) direction for doped ZnO. The lattice parameters a and c are estimated to be 3.24 and 5.20 ?, respectively. Transmission allowed to estimate the band gaps of ZnO layers. The electrochemical studies revealed that the corrosion resistance of the films depended on the concentration of dopants.

  5. A fluorescent tracer method for evaluating spray transport and fate of field and laboratory spray applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field and laboratory testing spray nozzles and application systems use spray collectors to assess where the spray deposits once it leaves the spray system. Tracer materials, such as oil and water soluble fluorescent dyes, can be mixed into spray solutions in small amounts with minimal impact on the...

  6. Electrical Characteristics and Preparation of (Ba0.5Sr0.5)TiO3 Films by Spray Pyrolysis and Rapid Thermal Annealing

    NASA Astrophysics Data System (ADS)

    Koo, Horng-Show; Chen, Mi; Ku, Hong-Kou; Kawai, Tomoji

    2007-04-01

    Functional films of (Ba0.5Sr0.5)TiO3 on Pt (1000 )/Ti (100 )/SiO2 (2000 )/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Barium nitrate, strontium nitrate and titanium isopropoxide are used as starting materials with ethylene glycol as solvent. For (Ba0.5Sr0.5)TiO3 functional thin film, thermal characteristics of the precursor powder scratched from as-sprayed films show a remarkable peak around 300-400 C and 57.7% weight loss up to 1000 C. The as-sprayed precursor film with coffee-like color and amorphous-like phase is transformed into the resultant film with white, crystalline perovskite phase and characteristic peaks (110) and (100). The resultant films show correspondent increases of dielectric constant, leakage current and dissipation factor with increasing annealing temperatures. The dielectric constant is 264 and tangent loss is 0.21 in the resultant films annealed at 750 C for 5 min while leakage current density is 1.5 10-6 A/cm2 in the film annealed at 550 C for 5 min.

  7. Method of synthesizing sprinkler spray patterns. Research report

    SciTech Connect

    Watkins, R.D.

    1983-06-01

    There are practical difficulties in obtaining data on water-sprinkler spray patterns over coal stockpiles under various wind conditions. A method is developed for synthesizing the spray-droplet patterns, based on laboratory tests to observe the droplets discharged from a sprinkler nozzle; this data is employed with the theoretical equations for droplet movement to calculate the trajectories of representative spray droplets, including cases where local air flows due to wind are important. From observations made by Watkins in the course of wind tunnel model studies of wind effects over coal stockpile areas, it was evident that local air flows could have a marked effect on the trajectories of water droplets from water sprinklers used for dust suppression.

  8. Method of producing pyrolysis gases from carbon-containing materials

    DOEpatents

    Mudge, Lyle K.; Brown, Michael D.; Wilcox, Wayne A.; Baker, Eddie G.

    1989-01-01

    A gasification process of improved efficiency is disclosed. A dual bed reactor system is used in which carbon-containing feedstock materials are first treated in a gasification reactor to form pyrolysis gases. The pyrolysis gases are then directed into a catalytic reactor for the destruction of residual tars/oils in the gases. Temperatures are maintained within the catalytic reactor at a level sufficient to crack the tars/oils in the gases, while avoiding thermal breakdown of the catalysts. In order to minimize problems associated with the deposition of carbon-containing materials on the catalysts during cracking, a gaseous oxidizing agent preferably consisting of air, oxygen, steam, and/or mixtures thereof is introduced into the catalytic reactor at a high flow rate in a direction perpendicular to the longitudinal axis of the reactor. This oxidizes any carbon deposits on the catalysts, which would normally cause catalyst deactivation.

  9. Processing and synthesis of multi-metallic nano oxide ceramics via liquid-feed flame spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Azurdia, Jose Antonio

    The liquid-feed flame spray pyrolysis (LF-FSP) process aerosolizes metal-carboxylate precursors dissolved in alcohol with oxygen and combusts them at >1500°C. The products are quenched rapidly (˜10s msec) to < 400°C. By selecting the appropriate precursor mixtures, the compositions of the resulting oxide nanopowders can be tailored easily, which lends itself to combinatorial studies of systems facilitating material property optimization. The resulting nanopowders typically consist of single crystal particles with average particle sizes (APS) < 35 nm, specific surface areas (SSA) of 20-60 m2/g and spherical morphology. LF-FSP provides access to novel single phase nanopowders, known phases at compositions outside their published phase diagrams, intimate mixing at nanometer length scales in multi metallic oxide nanopowders, and control of stoichiometry to ppm levels. The materials produced may exhibit unusual properties including structural, catalytic, and photonic ones and lower sintering temperatures. Prior studies used LF-FSP to produce MgAl2O4 spinel for applications in transparent armor and IR radomes. In these studies, a stable spinel structure with a (MgO)0.1(Al2O3)0.9 composition well outside the known phase field was observed. The work reported here extends this observation to two other spinel systems: Al2O3-NiO, Al2O3-CoOx; followed by three series of transition metal binary oxides, NiO-CoO, NiO-MoO3, NiO-CuO. The impetus to study spinels derives both from the fact that a number of them are known transparent ceramics, but also others offer high SSAs coupled with unusual phases that suggest potentially novel catalytic materials. Because LF-FSP provides access to any composition, comprehensive studies of the entire tie-lines were conducted rather than just compositions of value for catalytic applications. Initial efforts established baseline properties for the nano aluminate spinels, then three binary transition metal oxide sets (Ni-Co, Ni-Mo and Ni-Cu) known for their catalytic properties. These materials then serve as baseline studies for ternary systems, such as Al:(Ni-Co)O, or Al(Ni-Cu)O likely to offer superior catalytic properties because of the relatively high SSA Al2O3. The final chapter returns to photonic materials, in the MgO-Y2O 3 system targeting transparent ceramics through select compositions along the tie-line. The work presented here builds on the MgAl2O 4 spinel material and continues to develop the processing techniques required to achieve transparent nano-grained ceramic materials. Thus the overall goal of this dissertation was to systematically produce novel nano-oxide materials and characterized their material properties. The first chapters focus on solid solutions at low Ni or Co amounts that form phase pure spinels outside the expected composition range, at 21-22 mol % NiO and CoO. Additionally, (NiO)0.22(Al2O3) 0.78 was found to be very stable, as it did not convert to alpha-Al 2O3 plus cubic-NiO on heating to 1200°C for 10 h. The last chapter is a preliminary step toward identifying optimal Y 2O3-MgO powders that can be transparent ceramics. Ball milling led to much higher adsorption of surface species. Preliminary sintering studies of the this system showed that vacuum has the largest effect on lowering the temperature of maximum shrinkage rate by ≤ 80°C.

  10. The Controlled Single-Step Synthesis of Ag/TiO2 and Au/TiO2 by Ultrasonic Spray Pyrolysis (USP)

    NASA Astrophysics Data System (ADS)

    Bogovic, J.; Rudolf, R.; Friedrich, B.

    2016-01-01

    This article reports the synthesis of Ag/TiO2 and Au/TiO2 nanoparticles by single-step ultrasonic spray pyrolysis (USP) conducted by an investigation of the process parameters and the morphological characteristics of the obtained nanostructures. The influence of the ratio in the precursor solution, physical characteristics of used components, and temperature had a large influence on the formation of different nanoparticle morphologies. The experimental investigations were performed using classic USP equipment, with variations of the process parameters. Scanning electron microscopy, transmission electron microscopy, and focused ion beam analyses were used to characterize the complex nanostructures. Based on the obtained results, the optimal process window for the formation of the different morphologies for the Ag/TiO2 and Au/TiO2 nanoparticles is determined and the possibility of synthesis of the core-shell structures in one step by USP is confirmed.

  11. High electron mobility thin-film transistors based on Ga{sub 2}O{sub 3} grown by atmospheric ultrasonic spray pyrolysis at low temperatures

    SciTech Connect

    Thomas, Stuart R. E-mail: thomas.anthopoulos@imperial.ac.uk; Lin, Yen-Hung; Faber, Hendrik; Anthopoulos, Thomas D. E-mail: thomas.anthopoulos@imperial.ac.uk; Adamopoulos, George; Sygellou, Labrini; Stratakis, Emmanuel; Pliatsikas, Nikos; Patsalas, Panos A.

    2014-09-01

    We report on thin-film transistors based on Ga{sub 2}O{sub 3} films grown by ultrasonic spray pyrolysis in ambient atmosphere at 400–450 °C. The elemental, electronic, optical, morphological, structural, and electrical properties of the films and devices were investigated using a range of complementary characterisation techniques, whilst the effects of post deposition annealing at higher temperature (700 °C) were also investigated. Both as-grown and post-deposition annealed Ga{sub 2}O{sub 3} films are found to be slightly oxygen deficient, exceptionally smooth and exhibit a wide energy bandgap of ∼4.9 eV. Transistors based on as-deposited Ga{sub 2}O{sub 3} films show n-type conductivity with the maximum electron mobility of ∼2 cm{sup 2}/V s.

  12. The Effect of Film Composition on the Texture and Grain Size of CuInS2 Prepared by Spray Pyrolysis

    NASA Technical Reports Server (NTRS)

    Jin, Michael H.; Banger, Kulinder K.; Harris, Jerry D.; Hepp, Aloysius F.

    2003-01-01

    Ternary single-source precursors were used to deposit CuInS2 thin films using chemical spray pyrolysis. We investigated the effect of the film composition on texture, secondary phase formation, and grain size. As-grown films were most often In-rich. They became more (204/220)-oriented as indium concentration increased, and always contained a yet unidentified secondary phase. The (112)-prefened orientation became more pronounced as the film composition became more Cu-rich. The secondary phase was determined to be an In-rich compound based on composition analysis and Raman spectroscopy. In addition, as-grown Cu-rich (112)-oriented films did not exhibit the In-rich compound. Depositing a thin Cu layer prior to the growth of CuInS2 increased the maximum grain size from - 0.5 micron to - 1 micron, and prevented the formation of the In-rich secondary phase.

  13. High electron mobility thin-film transistors based on Ga2O3 grown by atmospheric ultrasonic spray pyrolysis at low temperatures

    NASA Astrophysics Data System (ADS)

    Thomas, Stuart R.; Adamopoulos, George; Lin, Yen-Hung; Faber, Hendrik; Sygellou, Labrini; Stratakis, Emmanuel; Pliatsikas, Nikos; Patsalas, Panos A.; Anthopoulos, Thomas D.

    2014-09-01

    We report on thin-film transistors based on Ga2O3 films grown by ultrasonic spray pyrolysis in ambient atmosphere at 400-450 °C. The elemental, electronic, optical, morphological, structural, and electrical properties of the films and devices were investigated using a range of complementary characterisation techniques, whilst the effects of post deposition annealing at higher temperature (700 °C) were also investigated. Both as-grown and post-deposition annealed Ga2O3 films are found to be slightly oxygen deficient, exceptionally smooth and exhibit a wide energy bandgap of ˜4.9 eV. Transistors based on as-deposited Ga2O3 films show n-type conductivity with the maximum electron mobility of ˜2 cm2/V s.

  14. Optical, electrical and structural properties of nano-pyramidal ZnO films grown on glass substrate by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Bedia, A.; Bedia, F. Z.; Aillerie, M.; Maloufi, N.; Ould Saad Hamady, S.; Perroud, O.; Benyoucef, B.

    2014-05-01

    Optical, electrical and structural properties of ZnO nano-pyramidal films, synthesized by chemical spray pyrolysis technique on glass substrates were investigated. A complete set of structural, optical and electrical parameters is proposed in this contribution. ZnO films possess polycrystalline wurtzite structure showing a preferential orientation along the c-axis as confirmed by XRD measurements. The structure has been investigated by using Raman spectroscopy, at 532 nm excitation source and the morphology is characterized by scanning electron microscopy (SEM). Link to the specific growing parameters, the morphology of the so-obtained films is rarely observed in nanostructures family with a diameter of ZnO hexagonal nano-pyramids in the range of 50-150 nm smaller than this usually obtained by spray pyrolysis. The strong peaks of the E2 Raman mode at 99.3 cm-1 (low) and 439.4 cm-1 (high), indicate a good crystal quality of the ZnO nano-pyramids. The existence of a compressive stress in the ZnO structure was pointed out by Raman scattering and estimated by XRD measurements. High optical transmittance value of the film above 90% in the visible region was observed and the optical band gap was found to be 3.273 eV at room temperature. The photoluminescence (PL) spectrum of ZnO hexagonal pyramid shows an intensity ratio of the UV emission to the visible band more than 20. By electrical characterizations of the ZnO films, we obtained the values of the resistivity and Hall mobility equal to 17 Ω cm and 8.49 cm2 V-1 s-1, respectively.

  15. Influence of impregnation method on metal retention of CCB-treated wood in slow pyrolysis process.

    PubMed

    Kinata, Silao Esprance; Loubar, Khaled; Bouslamti, Amine; Belloncle, Christophe; Tazerout, Mohand

    2012-09-30

    In the present work, the effects of copper, chromium and boron on the pyrolysis of wood and their distribution in the pyrolysis products were investigated. For this, the wood has been impregnated with chromium-copper-boron (CCB). In addition, to describe the effects of impregnation method, vacuum-pressure and dipping methods were also conducted. Thermogravimetric analysis (TGA) results show that an increase in the final residue and decrease in degradation temperature on both methods of treated wood compared to untreated wood. Then, slow pyrolysis experiments were carried out in a laboratory reactor. The mass balance of pyrolysis products is confirmed by TGA. Furthermore, the concentration of metals in the final residue is measured by inductively coupled plasma mass spectroscopy (ICP-MS). The results show that the final residue contains more than 45% of the initial amount of metal present in the treated wood. The phenomenon is more pronounced with vacuum-pressure treated wood. The heating values of pyrolysis products were analyzed. The heating value of charcoal obtained from treated and untreated wood is approximately same. But the heating value of tar from untreated wood is higher than the heating value of the tar from treated wood. PMID:22835770

  16. Structural, electrical and optical properties of nanostructured Cd1-xFexS thin films deposited by chemical spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Ibrahim, S. G.; Ubale, A. U.

    2014-11-01

    Multi-component nanostructured thin films of Cd1-xFexS were successfully deposited onto glass substrates from aqueous solutions of ferric chloride, cadmium chloride and thiourea using chemical spray pyrolysis technique. The structural, compositional and morphological studies were carried out by using X-ray diffractometer (XRD), energy dispersive X-ray analysis (EDAX) and scanning electron microscopy (SEM) and atomic force microscopy (AFM) respectively. The structural study revealed that, CdS, FeS and Cd1-xFexS films are nanocrystalline in nature with hexagonal lattice. The optical characterization shows that the band gap of the spray deposited CdS film is 2.20 eV and it increases with x' and becomes 2.44 eV for FeS. The electrical resistivity of Cd1-xFexS thin films is of the order of 106 ? cm and shows variation depending on x'. The thermo-emf measurement confirms n-type conductivity of Cd1-xFexS thin films.

  17. Effects of Doping Ratio and Thermal Annealing on Structural and Electrical Properties of Boron-Doped ZnO Thin Films by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Yu, Cheng-Chang; Hsu, Yu-Ting; Lee, Shao-Yi; Lan, Wen-How; Kuo, Hsin-Hui; Shih, Ming-Chang; Jui-Yang Feng, David; Huang, Kai-Feng

    2013-06-01

    Boron-doped zinc oxide (BZO) thin films have been fabricated by spray pyrolysis on a glass substrate. The morphology and electrical properties of the thin films were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed. It was found that [B]/[Zn] ratio altered both the microstructure and concentration of the BZO thin films. The film grain size was reduced by increasing the [B]/[Zn] ratio. The highest Hall mobility was 3.65 cm2 V-1 s-1 for the undoped ZnO thin film, and the highest carrier concentration of 1.0×1019 cm-3 was achieved for the as-deposited BZO thin film with [B]/[Zn] = 1.5 at. %. Conductivity was determined at different measurement temperatures and shallow donors provided the dominate conduction mechanism for the as-deposited BZO thin films. After 600 °C annealing, shallow level reduction and donors with a high activation energy of 129+/-6 meV in the BZO thin films were characterized, and the shallow donors that dominate the carrier concentration for the as-deposited spray-pyrolized BZO thin film were eliminated.

  18. Tin sulfide (SnS) nanostructured films deposited by continuous spray pyrolysis (CoSP) technique for dye-sensitized solar cells applications

    NASA Astrophysics Data System (ADS)

    Alam, Firoz; Dutta, Viresh

    2015-12-01

    Tin sulfide (SnS) nanostructured films have been deposited on transparent conducting glass substrate using continuous spray pyrolysis (CoSP) technique using aqueous spray solution of tin chloride and thiourea. Structural, morphological and optical properties of as-synthesized SnS nanostructured films showed the formation of (1 0 1) oriented orthorhombic SnS with nanoflakes having a direct band gap of 1.40 eV. X-ray photoelectron spectroscopy (XPS) analysis confirms the formation of pure SnS with Sn in +2 oxidation state. The SnS nanostructured film has also been characterized using Brunauer-Emmett-Teller (BET) technique to determine the surface area and pore volume which are found to be 11.4 m2/g and 0.02 cm2/g, respectively. The film has been used as a counter electrode (CE) in a triiodide/iodide (I3-/I-) based dye-sensitized solar cells (DSSCs). The DSSCs of 0.25 cm2 area with SnS nanostructured CE exhibits a lower power conversion efficiency (2.0 ± 0.06%) than that for the cell with standard platinum (Pt) CE (4.5 ± 0.13%). However, the usefulness of the CoSP technique for deposition of nanostructures SnS CE film has been established in the present study.

  19. Preparation and characterization of microparticles of piroxicam by spray drying and spray chilling methods

    PubMed Central

    Dixit, M.; Kini, A.G.; Kulkarni, P.K.

    2010-01-01

    Piroxicam, an anti-inflammatory drug, exhibits poor water solubility and flow properties, poor dissolution and poor wetting. Consequently, the aim of this study was to improve the dissolution of piroxicam. Microparticles containing piroxicam were produced by spray drying, using isopropyl alcohol and water in the ratio of 40:60 v/v as solvent system, and spray chilling technology by melting the drug and chilling it with a pneumatic nozzle to enhance dissolution rate. The prepared formulations were evaluated for in vitro dissolution and solubility. The prepared drug particles were characterized by scanning electron microscopy (SEM), differential scanning calorimeter, X-ray diffraction and Fourier transform infrared spectroscopy. Dissolution profile of the spray dried microparticles was compared with spray-chilled microparticles, pure and recrystallized samples. Spray dried microparticles and spray chilled microparticles exhibited decreased crystallinity and improved micromeritic properties. The dissolution of the spray dried microparticle and spray chilled particles were improved compared with recrystallized and pure sample of piroxicam. Consequently, it was believed that spray drying of piroxicam is a useful tool to improve dissolution but not in case of spray chilling. This may be due to the degradation of drug or variations in the resonance structure or could be due to minor distortion of bond angles. Hence, this spray drying technique can be used for formulation of tablets of piroxicam by direct compression with directly compressible tablet excipients. PMID:21589797

  20. Manual fire suppression methods on typical machinery space spray fires

    NASA Astrophysics Data System (ADS)

    Carhart, H. W.; Leonard, J. T.; Budnick, E. K.; Ouellette, R. J.; Shanley, J. H., Jr.

    1990-07-01

    A series of tests was conducted to evaluate the effectiveness of Aqueous Film Forming Foam (AFFF), potassium bicarbonate powder (PKP) and Halon 1211, alone and in various combinations, in extinguishing spray fires. The sprays were generated by JP-5 jet fuel issuing from an open sounding tube, and open petcock, a leaking flange or a slit pipe, and contacting an ignition source. The results indicate that typical fuel spray fires, such as those simulated in this series, are very severe. Flame heights ranged from 6.1 m (20 ft) for the split pipe to 15.2 m (50 ft) for the sounding tube scenario. These large flame geometries were accompanied by heat release rates of 6 MW to greater than 50 MW, and hazardous thermal radiation levels in the near field environment, up to 9.1 m (30 ft) away. Successful suppression of these fires requires both a significant reduction in flame radiation and delivery of a suppression agent to shielded areas. Of the nine suppression methods tested, the 95 gpm AFFF hand line and the hand line in conjunction with PKP were particularly effective in reducing the radiant flux.

  1. Method and apparatus for atomization and spraying of molten metals

    DOEpatents

    Hobson, D.O.; Alexeff, I.; Sikka, V.K.

    1988-07-19

    A method and device for dispersing molten metal into fine particulate spray, the method comprises applying an electric current through the molten metal and simultaneously applying a magnetic field to the molten metal in a plane perpendicular to the electric current, whereby the molten metal is caused to form into droplets at an angle perpendicular to both the electric current and the magnetic field. The device comprises a structure for providing a molten metal, appropriately arranged electrodes for applying an electric current through the molten metal, and a magnet for providing a magnetic field in a plane perpendicular to the electric current. 11 figs.

  2. Method and apparatus for atomization and spraying of molten metals

    DOEpatents

    Hobson, David O. (Oak Ridge, TN); Alexeff, Igor (Oak Ridge, TN); Sikka, Vinod K. (Clinton, TN)

    1990-01-01

    A method and device for dispersing molten metal into fine particulate spray, the method comprises applying an electric current through the molten metal and simultaneously applying a magnetic field to the molten metal in a plane perpendicular to the electric current, whereby the molten metal is caused to form into droplets at an angle perpendicular to both the electric current and the magnetic field. The device comprises a structure for providing a molten metal, appropriately arranged electrodes for applying an electric current through the molten metal, and a magnet for providing a magnetic field in a plane perpendicular to the electric current.

  3. Electrochemical properties of LiFe 0.9Mg 0.1PO 4 / carbon cathode materials prepared by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Teng, Tsung-Hsien; Yang, Mu-Rong; Wu, She-hung; Chiang, Yi-Ping

    2007-05-01

    The LiFe 0.9Mg 0.1PO 4/C powder of pure olivine phase can be prepared with the duplex process of spray pyrolysis synthesis (at 450 ∘C) and subsequent heat treatment (at 700 ∘C for 2, 4 and 8 h). From scanning electron microscopy observation with corresponding elemental mapping images of iron, phosphorous and magnesium, it could be found that the LiFe 0.9Mg 0.1PO 4 powders are covered with fine pyrolyzed carbon. Raman spectra indicate that the phase of carbon with higher electronic conductive phase is predominant when prolonged subsequent heat treatment is carried out. The carbon coatings on the LiFe 0.9Mg 0.1PO 4 surface can improve the conductivity of the LiFe 0.9Mg 0.1PO 4 powder (3.8×10 -5 S cm -1) to about a factor of ˜10 4 higher than the conductivity of LiFePO 4. The stability and cycle life of a charge/discharge cycle test of lithium ion secondary batteries are also enhanced. The results indicate that the LiFe 0.9Mg 0.1PO 4 powder, prepared at a pyrolysis temperature of 450 ∘C and with post-heat-treatment at 700 ∘C for 8 h, exhibits a specific initial discharge capacity of about 132 mA h g -1 at C/10 rate, 105 mA h g -1 at 1C, and 87 mA h g -1 at 5C.

  4. Sprayed coatings

    NASA Astrophysics Data System (ADS)

    Steffens, H. D.

    1980-03-01

    Thermal spraying is shown to be an efficient means for the protection of surface areas against elevated temperature, wear, corrosion, hot gas corrosion, and erosion in structural aircraft components. Particularly in jet engines, numerous parts are coated by flame, detonation, or plasma spraying techniques. The applied methods of flame, detonation, and plasma spraying are explained, as well as electric arc spraying. Possibilities for spray coatings which meet aircraft service requirements are discussed, as well as methods for quality control, especially nondestructive test methods. In particular, coating characteristics and properties obtained by different spray methods are described, and special attention is paid to low pressure plasma spraying.

  5. Formation of core-shell-structured Zn2SnO4-carbon microspheres with superior electrochemical properties by one-pot spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hong, Young Jun; Kang, Yun Chan

    2014-12-01

    Core-shell structured Zn2SnO4-carbon microspheres with different carbon contents are prepared by one-pot spray pyrolysis without any further heating process. A Zn2SnO4-carbon composite microsphere is prepared from one droplet containing Zn and Sn salts and polyvinylpyrrolidone (PVP). Melted PVP moves to the outside of the composite microsphere during the drying stage of the droplet. In addition, melting of the phase separated metal salts forms the dense core. Carbonization of the phase separated PVP forms the textured and porous thick carbon shell. The discharge capacities of the core-shell structured Zn2SnO4-carbon microspheres for the 2nd and 120th cycles at a current density of 1 A g-1 are 864 and 770 mA h g-1, respectively. However, the discharge capacities of the bare Zn2SnO4 microspheres prepared by the same process without PVP for the 2nd and 120th cycles are 1106 and 81 mA h g-1, respectively. The stable and reversible discharge capacities of the Zn2SnO4-carbon composite microspheres prepared from the spray solution with 15 g PVP decrease from 894 to 528 mA h g-1 as current density increases from 0.5 to 5 A g-1.Core-shell structured Zn2SnO4-carbon microspheres with different carbon contents are prepared by one-pot spray pyrolysis without any further heating process. A Zn2SnO4-carbon composite microsphere is prepared from one droplet containing Zn and Sn salts and polyvinylpyrrolidone (PVP). Melted PVP moves to the outside of the composite microsphere during the drying stage of the droplet. In addition, melting of the phase separated metal salts forms the dense core. Carbonization of the phase separated PVP forms the textured and porous thick carbon shell. The discharge capacities of the core-shell structured Zn2SnO4-carbon microspheres for the 2nd and 120th cycles at a current density of 1 A g-1 are 864 and 770 mA h g-1, respectively. However, the discharge capacities of the bare Zn2SnO4 microspheres prepared by the same process without PVP for the 2nd and 120th cycles are 1106 and 81 mA h g-1, respectively. The stable and reversible discharge capacities of the Zn2SnO4-carbon composite microspheres prepared from the spray solution with 15 g PVP decrease from 894 to 528 mA h g-1 as current density increases from 0.5 to 5 A g-1. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05373g

  6. Hemostatic powder spray: a new method for managing gastrointestinal bleeding.

    PubMed

    Changela, Kinesh; Papafragkakis, Haris; Ofori, Emmanuel; Ona, Mel A; Krishnaiah, Mahesh; Duddempudi, Sushil; Anand, Sury

    2015-05-01

    Gastrointestinal bleeding is a leading cause of morbidity and mortality in the United States. The management of gastrointestinal bleeding is often challenging, depending on its location and severity. To date, widely accepted hemostatic treatment options include injection of epinephrine and tissue adhesives such as cyanoacrylate, ablative therapy with contact modalities such as thermal coagulation with heater probe and bipolar hemostatic forceps, noncontact modalities such as photodynamic therapy and argon plasma coagulation, and mechanical hemostasis with band ligation, endoscopic hemoclips, and over-the-scope clips. These approaches, albeit effective in achieving hemostasis, are associated with a 5-10% rebleeding risk. New simple, effective, universal, and safe methods are needed to address some of the challenges posed by the current endoscopic hemostatic techniques. The use of a novel hemostatic powder spray appears to be effective and safe in controlling upper and lower gastrointestinal bleeding. Although initial reports of hemostatic powder spray as an innovative approach to manage gastrointestinal bleeding are promising, further studies are needed to support and confirm its efficacy and safety. The aim of this study was to evaluate the technical feasibility, clinical efficacy, and safety of hemostatic powder spray (Hemospray, Cook Medical, Winston-Salem, North Carolina, USA) as a new method for managing gastrointestinal bleeding. In this review article, we performed an extensive literature search summarizing case reports and case series of Hemospray for the management of gastrointestinal bleeding. Indications, features, technique, deployment, success rate, complications, and limitations are discussed. The combined technical and clinical success rate of Hemospray was 88.5% (207/234) among the human subjects and 81.8% (9/11) among the porcine models studied. Rebleeding occurred within 72 hours post-treatment in 38 patients (38/234; 16.2%) and in three porcine models (3/11; 27.3%). No procedure-related adverse events were associated with the use of Hemospray. Hemospray appears to be a safe and effective approach in the management of gastrointestinal bleeding. PMID:26082803

  7. Hemostatic powder spray: a new method for managing gastrointestinal bleeding

    PubMed Central

    Papafragkakis, Haris; Ofori, Emmanuel; Ona, Mel A.; Krishnaiah, Mahesh; Duddempudi, Sushil; Anand, Sury

    2015-01-01

    Gastrointestinal bleeding is a leading cause of morbidity and mortality in the United States. The management of gastrointestinal bleeding is often challenging, depending on its location and severity. To date, widely accepted hemostatic treatment options include injection of epinephrine and tissue adhesives such as cyanoacrylate, ablative therapy with contact modalities such as thermal coagulation with heater probe and bipolar hemostatic forceps, noncontact modalities such as photodynamic therapy and argon plasma coagulation, and mechanical hemostasis with band ligation, endoscopic hemoclips, and over-the-scope clips. These approaches, albeit effective in achieving hemostasis, are associated with a 5–10% rebleeding risk. New simple, effective, universal, and safe methods are needed to address some of the challenges posed by the current endoscopic hemostatic techniques. The use of a novel hemostatic powder spray appears to be effective and safe in controlling upper and lower gastrointestinal bleeding. Although initial reports of hemostatic powder spray as an innovative approach to manage gastrointestinal bleeding are promising, further studies are needed to support and confirm its efficacy and safety. The aim of this study was to evaluate the technical feasibility, clinical efficacy, and safety of hemostatic powder spray (Hemospray, Cook Medical, Winston-Salem, North Carolina, USA) as a new method for managing gastrointestinal bleeding. In this review article, we performed an extensive literature search summarizing case reports and case series of Hemospray for the management of gastrointestinal bleeding. Indications, features, technique, deployment, success rate, complications, and limitations are discussed. The combined technical and clinical success rate of Hemospray was 88.5% (207/234) among the human subjects and 81.8% (9/11) among the porcine models studied. Rebleeding occurred within 72 hours post-treatment in 38 patients (38/234; 16.2%) and in three porcine models (3/11; 27.3%). No procedure-related adverse events were associated with the use of Hemospray. Hemospray appears to be a safe and effective approach in the management of gastrointestinal bleeding. PMID:26082803

  8. Structural, microstructural, and optical properties of Zn1- x Mg x O thin films grown onto glass substrate by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hoggas, K.; Nouveau, Corinne; Djelloul, A.; Bououdina, M.

    2015-08-01

    Pure and doped Zn1- x Mg x O films were deposited onto glass substrate by ultrasonic spray pyrolysis technique. The variation of lattice constant and the blue shift of near-band-edge emission indicate that Zn2+ ions are successfully substituted by Mg2+ ions within ZnO lattice. At higher Mg content ( x ? 0.21), a drastic change appears in the morphology, as a result of structural changes from wurtzite (ZnO) structure into a mixture of wurtzite and cubic (MgO) phases. FTIR study indicated the existence of distinct characteristic absorption peaks at ~442 cm-1 for Zn-O stretching mode that shifted toward the red region with the increase in Mg content. In addition to the host phonons of ZnO, one additional band was observed around 523 cm-1, presumably attributed to the Mg-related vibrational mode. The optical constants and thickness of thin films have been determined using experimental transmittance data. The luminescence intensity at 2.63 eV of Zn0.85Mg0.15O thin films was found to be approximately 13 times higher than that of pure ZnO film measured under the same excitation conditions.

  9. Tin-Incorporation Induced Changes in the Microstructural, Optical, and Electrical Behavior of Tungsten Oxide Nanocrystalline Thin Films Grown Via Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Mukherjee, Ramnayan; Prajapati, C. S.; Sahay, P. P.

    2014-12-01

    Undoped and Sn-doped WO3 thin films were grown on cleaned glass substrates by chemical spray pyrolysis, using ammonium tungstate (NH4)2WO4 as the host precursor and tin chloride (SnCl45H2O) as the source of dopant. The XRD spectra confirm the monoclinic structure with a sharp narrow peak along (200) direction along with other peaks of low relative intensities for all the samples. On Sn doping, the films exhibit reduced crystallinity relative to the undoped film. The standard deviation for relative peak intensity with dopant concentration shows enhancement in heterogeneous nucleation growth. As evident from SEM images, on Sn doping, appearance of island-like structure (i.e., cluster of primary crystallites at few places) takes place. The transmittance has been found to decrease in all the Sn-doped films. The optical band gap has been calculated for both direct and indirect transitions. On Sn doping, the direct band gap shows a red shift and becomes 2.89 eV at 2 at.% doping. Two distinct peaks, one blue emission at 408 nm and other green emission at 533 nm, have been found in the PL spectra. Electrical conductivity has been found to increase with Sn doping.

  10. Improving electrical performance of ultrasonic spray pyrolysis grown textured ZnO films by introducing In2O3:W interface layer

    NASA Astrophysics Data System (ADS)

    Jiao, Bao-chen; Zhang, Xiao-dan; Wei, Chang-chun; Huang, Qian; Chen, Xin-liang; Zhao, Ying

    2013-08-01

    The main focus of this paper was the improvement in the Hall mobility of ZnO films prepared by ultrasonic spray pyrolysis. In order to achieve low resistivity and high transparency simultaneously, we used the tungsten doped In2O3 (IWO) deposited by electron beam evaporation as interface layer to prepare IWO/ZnO films. Hall mobility can be improved to close to 50 cm2 V-1 s-1, and the resistivity kept as low as 1.48 × 10-3 Ω cm, while the transparency of the IWO/ZnO was about 80% in the range of 400-2000 nm (including glass) at the same time. X-ray diffraction and scanning electron microscope measurements were used to investigate the structure properties and surface morphologies of the ZnO and IWO/ZnO films. Secondary ion mass spectrometry measurement revealed that the indium and tungsten can diffuse from the IWO layer into the following deposited ZnO layer. The oxygen interstitial of the ZnO layer can be decreased by the tungsten diffusing from the IWO layer, and this was the main reason of the higher Hall mobility. Atom force microscopy measurement indicated the IWO/ZnO films with high value texture.

  11. Investigations on the crystalline, topographic, electrical and optical characteristics of doubly doped (Si + F) SnO2 films deposited using spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Turgut, G.; Thirumurugan, K.; Ravichandran, K.

    2015-10-01

    Silicon and fluorine (Si + F) co-doped SnO2 thin films were deposited on soda lime glass substrate using the spray pyrolysis technique. The Si and F doping levels were varied from 0-10 and 2.5-10 in steps of 2.5 at. %, respectively. Initially the optimum doping level of Si is found (7.5 at. %) at which the film exhibits the minimum electrical resistivity value (4.23 × 10-3 Ω cm) and then the doping level of F is varied and it is found to be better at 10 at. % on which it offers lower resistivity of 1.96 × 10-4 Ω cm. From the structural studies, it is observed that the preferential orientation of all the films is along (2 1 1) plane irrespective of dopant and level of doping, but the peak intensity decreases as the doping level increases. The average transmittance of the all the films is found to be around 75% in the visible region and the optical band gap of the films are found to be in the region of 3.79-3.99 eV.

  12. Effects of Different Salts on Salt-Assisted Ultrasonic Spray Pyrolysis (SA-USP) Calcination for the Synthesis of Strontium Ferrite.

    PubMed

    Hwang, Tea-Yeon; An, Guk-Hwan; Cho, Jeong-Ho; Kim, Jongryoul; Choa, Yong-Ho

    2015-10-01

    Strontium ferrite (hexaferrite), SrFe12O19, was successfully fabricated in sizes ranging from hundreds of nanometers to several micrometers by salt-assisted ultrasonic spray pyrolysis-calcination using different salt media. All samples were single phases of SrFe12O19 without the intermediate phase, ?-Fe2O3, and their morphology was hexagonal. As calcination temperature increased, the size of as-calcined samples and saturation magnetization, Ms, increased while coercivity decreased. The particle size of the obtained nanoparticles varied depending on the salt media and calcination temperatures. The best magnetic properties obtained in this experiment were a coercivity of 6973 Oe with a saturation magnetization of 68.3 emu/g. To the best of our knowledge, these coercivity values are the highest ever obtained. We propose a detailed mechanism explaining the growth of these particles and conclude that the resulting single-domain particle size is about 70 nm, taking into account of factors affecting coercivity in ferrite nano- to micro-sized particles. PMID:26726463

  13. Physical properties of Zn doped TiO2 thin films with spray pyrolysis technique and its effects in antibacterial activity

    NASA Astrophysics Data System (ADS)

    Arunachalam, A.; Dhanapandian, S.; Manoharan, C.; Sivakumar, G.

    2015-03-01

    Zinc doped Titanium dioxide (TiO2: Zn) thin films were deposited onto glass substrates by the spray pyrolysis technique with the substrate temperature 450 °C. The structural, optical, photoluminescence (PL) properties and morphological studies were investigated for the films deposited with various doping concentration (0, 2, 4, 6 and 8 at.%) of zinc. The results of X-ray diffraction (XRD) had shown the presence of anatase peak with a strong orientation along (1 0 1) plane at 8 at.% of Zn-doped TiO2 film. Scanning electron microscopy (SEM) study showed the uniform distribution of grains with porous nature. Atomic force microscopy (AFM) observations indicated the tetragonal shape at 8 at.% of Zn-doped TiO2 with the particle size and decrease in surface roughness. The emission at 398 nm was observed at the 8 at.% of Zn-doped TiO2 thin film. The carrier concentration and Hall mobility was increased with doping. The antibacterial activity was highly yielded for the Zn-doped TiO2 thin films.

  14. Effect of Sn doping on the structural, optical and electrical properties of TiO2 films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Arunachalam, A.; Dhanapandian, S.; Manoharan, C.

    2016-02-01

    In this work, highly oriented pure and Tin-doped Titanium dioxide (Sn-doped TiO2) with porous nature photoelectrodes were deposited on ITO glass plates using spray pyrolysis technique. The XRD pattern revealed the formation of anatase TiO2 with the maximum intensity of (101) plane while doping 6 at% of Sn. The morphological studies depicted the porous nature with the uniform arrangement of small-sized grains. The presence of tin confirmed with the EDX spectra. The size of particles of 13 nm was observed from High Resolution Transmission Electron Microscopy (HR-TEM) analysis. The average transmittance was about 85% for the doped photoelectrode and was observed for the photoelectrode deposited with 6 at% of tin, with decreased energy band gap. The PL study showed the emission peak at 391 nm. The maximum carrier concentration and Hall mobility was observed for the photoelectrode deposited with 6 at% of tin. With these studies, the DSSCs were prepared separately with the dye extracted from Hibiscus Rosasinesis and Hibiscus Surttasinesis and their efficiency was maximum for the DSSC prepared with 6 at% of tin.

  15. Effect of Li3+ heavy ion irradiation on the Mo doped In2O3 thin films prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Parthiban, S.; Elangovan, E.; Ramamurthi, K.; Kanjilal, D.; Asokan, K.; Martins, R.; Fortunato, E.

    2011-03-01

    The high visible-near infrared transparent and high carrier mobility (μ) Mo doped (0.5 at%) indium oxide (IMO) films were deposited by the spray pyrolysis technique. The deposited films were irradiated by 50 MeV Li3+ ions with different fluences of 1 × 1011, 1 × 1012 and 1 × 1013 ions cm-2. X-ray diffraction analysis confirmed the cubic bixbyite structure of indium oxide. A fascinating feature is that the ion irradiation process has introduced a fraction of the molybdenum oxide phase. The μ of as-deposited IMO films is decreased from ~122.4 to 93.3 cm2 V-1 s-1, following the ion irradiation. The theoretically calculated μ and carrier density values were correlated with those measured experimentally. The transport mechanism has been analysed based on the ionized and neutral impurity scattering centres. The average transmittance (400-2500 nm) of the as-deposited IMO films is decreased from 83% to 60% following irradiation.

  16. Preparation and characterization of nanostructures of in-doped ZnO films deposited by chemically spray pyrolysis: Effect of substrate temperatures

    NASA Astrophysics Data System (ADS)

    Benhaliliba, M.; Benouis, C. E.; Mouffak, Z.; Ocak, Y. S.; Tiburcio-Silver, A.; Aida, M. S.; Garcia, A. A.; Tavira, A.; Sanchez Juarez, A.

    2013-11-01

    We deposited undoped (ZnO) and indium-doped ZnO (IZO) films onto glass substrate via ultrasonic spray pyrolysis technique. The variation in structural, surface morphology, electrical, optical and photoluminescent properties as a function of substrate temperature is investigated. X-rays pattern confirms that as-synthesized IZO phase is grown along a (002) preferential plane. Nanosized grains (<50 nm) are determined by X-ray analysis. Morphology of as-grown films shows broadened nanostructures which have grown along c-axis and nanostructures are found to be smooth (RMS˜60 nm). Study by spectrophotometer reveals that the as-grown films are highly transparent in the visible and IR spectra (T ˜ 88%), and that the bandgap is slightly narrowed (3.17 eV). Electrical measurements confirm the enhancement of conductivity, ρ < 1 Ω cm, due to indium incorporation into the starting solution. An electron concentration of 1017 cm-3 and a mobility of 3 cm2/Vs are found for IZO films grown at 400 °C. The photoluminescence analysis demonstrates strong yellow (2.1 eV) and blue (2.8 eV) light and weak green (2.3 eV) emissions.

  17. High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

  18. Preparation and characterization of indium doped CdS{sub 0.2}Se{sub 0.8} thin films by spray pyrolysis

    SciTech Connect

    Yadav, A.A.; Masumdar, E.U.

    2010-10-15

    The CdS{sub 0.2}Se{sub 0.8} and indium doped CdS{sub 0.2}Se{sub 0.8} thin films have been deposited onto the amorphous glass and fluorine doped tin oxide coated glass substrates by spray pyrolysis. The doping concentration of indium has been optimized by photoelectrochemical characterization technique. The structural, surface morphological, optical and electrical properties of CdS{sub 0.2}Se{sub 0.8} and indium doped CdS{sub 0.2}Se{sub 0.8} thin films have been studied. X-ray diffraction studies reveal that the films are polycrystalline in nature with hexagonal crystal structure. Scanning electron microscopy studies reveal that the grains are uniform with uneven spherically shaped, distributed over the entire substrate surface. The complete surface morphology has been changed after doping. In optical studies, the transition of the deposited films is found to be direct allowed with optical energy gaps decreasing from 1.91 to 1.67 eV with indium doping. Semiconducting behavior has been observed from resistivity measurements. The thermoelectric power measurements reveal that the films exhibit n-type conductivity.

  19. Spray pyrolysis of tin selenide thin-film semiconductors: the effect of selenium concentration on the properties of the thin films

    NASA Astrophysics Data System (ADS)

    Fadavieslam, M. R.; Bagheri-Mohagheghi, M. M.

    2013-08-01

    Thin films of tin selenide (SnxSey) with an atomic ratio of , 1 and 1.5 were prepared on a glass substrate at T = 470C using a spray pyrolysis technique. The initial materials for the preparation of the thin films were an alcoholic solution consisting of tin chloride (SnCl4 5H2O) and selenide acide (H2SeO3). The prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy, scanning tunneling microscopy, scanning helium ion microscopy, and UV-vis spectroscopy. The photoconductivity and thermoelectric effects of the SnxSey thin films were then studied. The SnxSey thin films had a polycrystalline structure with an almost uniform surface and cluster type growth. The increasing atomic ratio of r in the films, the optical gap, photosensitivity and Seebeck coefficient were changed from 1.6 to 1.37 eV, 0.01 to 0.31 and -26.2 to -42.7 mV/K (at T = 350 K), respectively. In addition, the XRD patterns indicated intensity peaks in r = 1 that corresponded to the increase in the SnSe and SnSe2 phases.

  20. The influence of Al doping on the electrical, optical and structural properties of SnO2 transparent conducting films deposited by the spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Bagheri-Mohagheghi, Mohammad-Mehdi; Shokooh-Saremi, Mehrdad

    2004-04-01

    In this study, the influence of increasing the Al concentration on the electrical, optical and structural properties of spray-pyrolysis-deposited SnO2 films has been investigated. The SnO2 : Al films were deposited at a substrate temperature of 480C using a hydro-alcoholic solution consisting of tin and aluminium chlorides with various Al-doping levels from 0 to 30 wt% in solution. The [Al]/[Sn] atomic ratios were from 0 to 12.1 in films. The results of x-ray diffraction have shown that the deposited films are polycrystalline without any second phases with preferential orientations along the (110), (211) and (301) planes and an average grain size of 28.7 nm. Also, the Hall effect and resistivity measurements of the films show that for a specific acceptor dopant (Al) concentration (8.0 at% in film), majority carriers convert from electrons to holes and p-conductivity dominates. The optical absorption edge for undoped SnO2 films lies at 4.105 eV, whereas for high acceptor-doped films it shifts towards lower energies (longer wavelengths) in the range of 4.105-3.604 eV.

  1. Effect of Sb dopant on the structural, optical and electrical properties of SnS thin films by spray pyrolysis technique.

    PubMed

    Santhosh Kumar, K; Manoharan, C; Dhanapandian, S; Gowri Manohari, A

    2013-11-01

    Thin films of antimony doped tin sulphide (SnS:Sb) with different antimony concentrations have been prepared by the spray pyrolysis technique at the substrate temperature of 350C. The physical properties of the films were studied as a function of increase in antimony dopant concentration (up to 10at.%). The films were characterized by different techniques to study their structural, optical and electrical properties. The X-ray diffraction analysis revealed that the films were polycrystalline in nature and having orthorhombic crystal structure with a preferred orientation in (111) direction. Due to Sb doping, the crystalline quality and the preferential orientation of SnS films were improved up to 6at.% of doping concentration. However, when doping concentration was increased above 6at.%, the crystalline quality and the preferential orientation of SnS films was deteriorated. Atomic force microscopy images revealed that the surface roughness of the films increased due to Sb doping. Optical measurements showed that the band gap values decreased from 1.60eV to 1.15eV with increase in Sb concentration. The photoluminescence spectra displayed that all the samples have an emission peak centered at 760nm. At 6at.% of Sb doping, the film has the lowest resistivity of 2.59810(-2)?cm while the carrier concentration was high. PMID:23892347

  2. Effect of F doping on physical properties of (211) oriented SnO2 thin films prepared by jet nebulizer spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Thirumoorthi, M.; Prakash, J. Thomas Joseph

    2016-01-01

    Transparent conducting fluorine doped tin oxide (FTO) thin films have been prepared jet nebulizer spray pyrolysis technique at 500 °C for different doping concentrations. The X-ray diffraction spectra confirm the polycrystalline nature of SnO2: F with tetragonal structure. All the films show a preferred growth orientation along (211) diffraction plane. Scanning electron microscope images show that the films have a uniform surface morphology with well defined pyramid like grains. The AFM results of the films indicate that the surface roughness is increased with F doping. The optical transmittance of FTO films is improved from 75 to 92% in the visible region of the solar spectrum and the optical absorption of the films is very low. The blue shift of optical band of the films is explained by Burstain-Mass effect. The observed blue shift of the UV emission band in the photoluminescence spectra confirms the incorporation of F into tin oxide crystal lattice. The presence of functional groups and chemical bonding were confirmed by FTIR. Hall Effect measurements show that the prepared films having n-type conductivity with low resistivity (2.3 × 10-4 Ω-cm) and high carrier concentrations (6.9 × 1020 cm-3).

  3. Colloidal spray method for low cost thin coating deposition

    DOEpatents

    Pham, Ai-Quoc; Glass, Robert S.; Lee, Tae H.

    2005-01-25

    A dense or porous coating of material is deposited onto a substrate by forcing a colloidal suspension through an ultrasonic nebulizer and spraying a fine mist of particles in a carrier medium onto a sufficiently heated substrate. The spraying rate is essentially matched to the evaporation rate of the carrier liquid from the substrate to produce a coating that is uniformly distributed over the surface of the substrate. Following deposition to a sufficient coating thickness, a single sintering step may be used to produce a dense ceramic coating. Using this method, coatings ranging in thickness from about one to several hundred microns can be obtained. By using a plurality of compounds in the colloidal suspension, coatings of mixed composition can be obtained. By using a plurality of solutions and separate pumps and a single or multiple ultrasonic nebulizer(s), and varying the individual pumping rates and/or the concentrations of the solutions, a coating of mixed and discontinuously graded (e.g., stepped) or continuously graded layers may be obtained. This method is particularly useful for depositing ceramic coatings. Dense ceramic coating materials on porous substrates are useful in providing improved electrode performance in devices such as high power density solid oxide fuel cells. Dense ceramic coatings obtained by the invention are also useful for gas turbine blade coatings, sensors, steam electrolyzers, etc. The invention has general use in preparation of systems requiring durable and chemically resistant coatings, or coatings having other specific chemical or physical properties.

  4. Colloidal spray method for low cost thin coating deposition

    DOEpatents

    Pham, Ai-Quoc; Glass, Robert S.; Lee, Tae H.

    2002-01-01

    A dense or porous coating of material is deposited onto a substrate by forcing a colloidal suspension through an ultrasonic nebulizer and spraying a fine mist of particles in a carrier medium onto a sufficiently heated substrate. The spraying rate is essentially matched to the evaporation rate of the carrier liquid from the substrate to produce a coating that is uniformly distributed over the surface of the substrate. Following deposition to a sufficient coating thickness, a single sintering step may be used to produce a dense ceramic coating. Using this method, coatings ranging in thickness from about one to several hundred microns can be obtained. By using a plurality of compounds in the colloidal suspension, coatings of mixed composition can be obtained. By using a plurality of solutions and separate pumps and a single or multiple ultrasonic nebulizer(s), and varying the individual pumping rates and/or the concentrations of the solutions, a coating of mixed and discontinuously graded (e.g., stepped) or continuously graded layers may be obtained. This method is particularly useful for depositing ceramic coatings. Dense ceramic coating materials on porous substrates are useful in providing improved electrode performance in devices such as high power density solid oxide fuel cells. Dense ceramic coatings obtained by the invention are also useful for gas turbine blade coatings, sensors, steam electrolyzers, etc. The invention has general use in preparation of systems requiring durable and chemically resistant coatings, or coatings having other specific chemical or physical properties.

  5. Structural, optical and electrical properties of CuInS2 thin films prepared by chemical spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Terasako, Tomoaki; Uno, Yuji; Inoue, Seiki; Kariya, Tetsuya; Shirakata, Sho

    2006-09-01

    Polycrystalline CuInS2 thin films were prepared by chemical spray pyrolisis (CSP) on glass sustrate from the ethanol aqueous solution containing CuCl2, InCl3 and thiourea. Structual, electrical and optical properties were systematically studied in terms of substrate temperature, pH and the ion ratio (Cu/In) of the spray solution. Although the In-rich films were composed of CuInS2 and In2S3, the In2S3 content in the film decreased with Cu/In ratio. Appearance of Raman peaks at 288 and 298 cm-1 indicated that the films contained CuInS2 with chalcopyrite and CuAu phases. Typical grain size in the Cu-rich films was 200 nm. Optical gap energies were approximately 0.1-0.2eV smaller than the bandgap energy of the CuInS2 bulk crystal. Resisitivity of the Cu-rich films without In2S3 secondary phase was 0.2-5 cm.

  6. Spray automated balancing of rotors: Methods and materials

    NASA Technical Reports Server (NTRS)

    Smalley, Anthony J.; Baldwin, Richard M.; Schick, Wilbur R.

    1988-01-01

    The work described consists of two parts. In the first part, a survey is performed to assess the state of the art in rotor balancing technology as it applies to Army gas turbine engines and associated power transmission hardware. The second part evaluates thermal spray processes for balancing weight addition in an automated balancing procedure. The industry survey reveals that: (1) computerized balancing equipment is valuable to reduce errors, improve balance quality, and provide documentation; (2) slow-speed balancing is used exclusively, with no forseeable need for production high-speed balancing; (3) automated procedures are desired; and (4) thermal spray balancing is viewed with cautious optimism whereas laser balancing is viewed with concern for flight propulsion hardware. The FARE method (Fuel/Air Repetitive Explosion) was selected for experimental evaluation of bond strength and fatigue strength. Material combinations tested were tungsten carbide on stainless steel (17-4), Inconel 718 on Inconel 718, and Triballoy 800 on Inconel 718. Bond strengths were entirely adequate for use in balancing. Material combinations have been identified for use in hot and cold sections of an engine, with fatigue strengths equivalent to those for hand-ground materials.

  7. Screen-printed (La,Sr)CrO3 coatings on ferritic stainless steel interconnects for solid oxide fuel cells using nanopowders prepared by means of ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Brylewski, Tomasz; Dabek, Jaroslaw; Przybylski, Kazimierz; Morgiel, Jerzy; Rekas, Mieczyslaw

    2012-06-01

    In order to protect the cathode from chromium poisoning and improve electrical resistance, a perovskite (La,Sr)CrO3 coating was deposited on the surface of a DIN 50049 ferritic stainless steel by means of the screen-printing method, using a paste composed of an ultra-fine powder prepared via ultrasonic spray pyrolysis. Investigations of the oxidation process of the coated steel in air and the Ar-H2-H2O gas mixture at 1073 K for times up to 820 h showed high compactness of the protective film, good adhesion to the metal substrate, as well as area specific resistance (ASR) at a level acceptable for metallic SOFC interconnect materials. The microstructure, nanostructure, phase composition of the thick film, and in particular the film/substrate interface, were examined via chemical analyses by means of SEM-EDS and TEM-SAD. It was shown that the (La,Sr)CrO3 coating interacts with the steel during long-term thermal oxidation in the afore-mentioned conditions and intermediate, chromia-rich and/or spinel multilayer interfacial zones are formed. Cr-vaporization tests showed that the (La,Sr)CrO3 coating may play the role of barriers that decrease the volatilization rate of chromia species.

  8. Numerical modeling of spray combustion with an advanced VOF method

    NASA Technical Reports Server (NTRS)

    Chen, Yen-Sen; Shang, Huan-Min; Shih, Ming-Hsin; Liaw, Paul

    1995-01-01

    This paper summarizes the technical development and validation of a multiphase computational fluid dynamics (CFD) numerical method using the volume-of-fluid (VOF) model and a Lagrangian tracking model which can be employed to analyze general multiphase flow problems with free surface mechanism. The gas-liquid interface mass, momentum and energy conservation relationships are modeled by continuum surface mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed flow regimes. The objectives of the present study are to develop and verify the fractional volume-of-fluid cell partitioning approach into a predictor-corrector algorithm and to demonstrate the effectiveness of the present approach by simulating benchmark problems including laminar impinging jets, shear coaxial jet atomization and shear coaxial spray combustion flows.

  9. Molecular characterization and comparison of shale oils generated by different pyrolysis methods

    USGS Publications Warehouse

    Birdwell, Justin E.; Jin, Jang Mi; Kim, Sunghwan

    2012-01-01

    Shale oils generated using different laboratory pyrolysis methods have been studied using standard oil characterization methods as well as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with electrospray ionization (ESI) and atmospheric photoionization (APPI) to assess differences in molecular composition. The pyrolysis oils were generated from samples of the Mahogany zone oil shale of the Eocene Green River Formation collected from outcrops in the Piceance Basin, Colorado, using three pyrolysis systems under conditions relevant to surface and in situ retorting approaches. Significant variations were observed in the shale oils, particularly the degree of conjugation of the constituent molecules and the distribution of nitrogen-containing compound classes. Comparison of FT-ICR MS results to other oil characteristics, such as specific gravity; saturate, aromatic, resin, asphaltene (SARA) distribution; and carbon number distribution determined by gas chromatography, indicated correspondence between higher average double bond equivalence (DBE) values and increasing asphaltene content. The results show that, based on the shale oil DBE distributions, highly conjugated species are enriched in samples produced under low pressure, high temperature conditions, and under high pressure, moderate temperature conditions in the presence of water. We also report, for the first time in any petroleum-like substance, the presence of N4 class compounds based on FT-ICR MS data. Using double bond equivalence and carbon number distributions, structures for the N4 class and other nitrogen-containing compounds are proposed.

  10. Method and apparatus for pyrolysis of atactic polypropylene

    DOEpatents

    Staffin, H. Kenneth (New Brunswick, NJ); Roaper, R. B. (Martinsville, NJ)

    1986-09-23

    This invention relates to an apparatus and a method for pyrolytic decomposition of polymeric materials into lower molecular weight products involving the heat treatment of raw polymeric material within reactive conduits submerged in a fluidized bed furnace operated at pyrolizing temperatures.

  11. Method and apparatus for pyrolysis of atactic polypropylene

    DOEpatents

    Staffin, H.K.; Roaper, R.B.

    1986-09-23

    This invention relates to an apparatus and a method for pyrolytic decomposition of polymeric materials into lower molecular weight products involving the heat treatment of raw polymeric material within reactive conduits submerged in a fluidized bed furnace operated at pyrolyzing temperatures. 1 fig.

  12. Structure and optical band gap of ZnO1-xSx thin films synthesized by chemical spray pyrolysis for application in solar cells

    NASA Astrophysics Data System (ADS)

    Thankalekshmi, Ratheesh R.; Rastogi, A. C.

    2012-09-01

    Highly crystalline c-axis oriented and homogeneous ZnO1-xSx films with sulfur composition 0.05 ? x ? 0.9 without phase separation were deposited using spray pyrolysis of aqueous precursors. A mechanism of film growth is proposed which envisages a slower kinetics of ZnO precursor decomposition and its specific by-products combined with S-precursor decomposition which enables homogeneous ZnO1-xSx phase formation over a wide S-composition range 0.05 ? x ? 0.9. This is achieved by controlling the substrate temperature to ? 300 C and the spray rate at 3 ml/min. The ZnO1-xSx films primarily form by S2- substitution at the O2- lattice sites which is confirmed by detailed analysis of the Zn2p, S2p and O1s x-ray photoelectron spectroscopy peaks. With the increasing of S-content, a structural transformation is observed in ZnO1-xSx films; for x < 0.3, the ZnO1-xSx films in the oxygen-rich phase are in ZnO wurtzite crystal structure and for x ? 0.44, the ZnO1-xSx films lie in the sulfur-rich phase with ?-ZnS structure. At threshold x = 0.3, in the structural transition state, diffraction peaks corresponding to both structural phases are observed. The optical transmission spectra at the band gap transition energy position shift to the red side for 0.05 ? x < 0.52 and towards the blue side with the further increase in S-content in the 0.52 < x ? 0.9 range. Optical band gap energy determined for ZnO1-xSx films show strong band gap bowing over the entire S-composition range, 0.05 ? x ? 0.9. The band gap modulation with increased S-content is inconsistent with the use of a single bowing parameter. A bowing parameter of 2.5 eV shows a closer fit for 0.05 ? x < 0.52. By accounting for additional effect of the strain energy on the band gap due to addition of excess S-content, a closer fit for the observed variation in the band gap is explained in the 0.52 < x ? 0.9 composition range. Electrical resistivity variation with S-content is consistent with the compensating effect of S2- substitution at the O2- sites in ZnO1-xSx films.

  13. Highly durable superhydrophobic coatings with gradient density by movable spray method

    NASA Astrophysics Data System (ADS)

    Tenjimbayashi, Mizuki; Shiratori, Seimei

    2014-09-01

    Superhydrophobic surface is expected to be applied in anti-fouling, anti-icing, and anti-bacterial. However, practical use is interrupted by low mechanical strength, time-consuming process, and limited coating substrate. Here highly durable superhydrophobic coatings were prepared by simple and novel spraying method, which sprays with changing the "spray distance between substrate and spray" (SD), named "movable spray method." We prepared the solution that changes wettability and durability with spraying distance by mixing SiO2 nanoparticles and ethyl alpha cyanoacrylate polymer (EAC). Then, we evaluated the chemical components and surface morphologies of each spraying distance coatings (0 50 cm) by XPS, SEM, and laser scanning microscope. It revealed that surface roughness and SiO2/EAC ratio increased as the SD increases. Thus, durable superhydrophobic coatings were designed by spraying with increasing SD gradually. Glow discharge-optical emission spectrometry analysis revealed that designed coatings showed the gradual increase of SiO2/EAC ratio. As a result, coatings prepared on glass, wood, or aluminum substrates maintained their superhydrophobicity up to the abrasion at 40 kPa. This movable spray method is simple coating by the wet process and prepares robust hydrophobic coating on complex shape and large area substrates. The gradient functional surface was found to have mechanical durability and superhydrophobicity, and wide area applications will be expected.

  14. Comparative studies of CdS, CdS:Al, CdS:Na and CdS:(Al-Na) thin films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Y?lmaz, S.; Atasoy, Y.; Tomakin, M.; Bacaks?z, E.

    2015-12-01

    In the present study, the spray pyrolysis technique was used to prepare pure CdS, 4 at.% Al-doped CdS, 4 at.% Na-doped CdS and (4 at.% Al, 4 at.% Na)-co-doped CdS thin films. It was found from X-ray diffraction data that all the specimens showed hexagonal wurtzite structure with the preferred orientation of (101). Scanning electron microscopy results indicated that 4 at.% Al-doping caused a grain growth in the morphology of CdS thin films whereas the 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping led to porous structure with small grains. The band gap value of CdS thin films increased to 2.42eV after 4 at.% Al-doping. However, it reduced to 2.30eV and 2.08eV for 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping, respectively. The room temperature photoluminescence measurements illustrated that the peak intensity of CdS thin films enhanced with 4 at.% Al-doping while 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping caused a decline in the intensity. The maximum carrier concentration and minimum resistivity were obtained for 4 at.% Al-doped CdS thin films, which is associated with the grain growth. Furthermore, (4 at.% Al, 4 at.% Na)-co-doping gave rise to a slight reduction in the carrier concentration and a slight increment in the resistivity. As a result, it can be said that 4 at.% Al-doped CdS thin films exhibited the best electrical and optical properties, which is important for the opto-electronic applications.

  15. The Effect of Mn Incorporation on the Structural, Morphological, Optical, and Electrical Features of Nanocrystalline ZnO Thin Films Prepared by Chemical Spray Pyrolysis Technique

    NASA Astrophysics Data System (ADS)

    Yilmaz, Mehmet; Aydoğan, Şakir

    2015-06-01

    Un-doped and Mn-doped ZnO nanocrystalline thin films and n-ZnO /n-Si heterojunction have been prepared by chemical spray pyrolysis technique. The microstructure, morphology, optical, and electrical properties have been studied. The X-ray analyses have revealed that all films are in single phase and have wurtzite structure. Besides, it has been indicated that there are not any secondary phases. The optical properties have been evaluated by UV-Vis measurement. It has shown that band gap decreases with Mn incorporation from 3.29 to 3.19 eV. Schottky diode applications of the films have been performed by evaporation of Au on pure and Mn-doped ZnO films. Current-voltage (I-V) and capacitance-voltage (C-V) measurements of the n-ZnO /n-Si heterojunction indicate good diode characteristic and the barrier heights have been calculated as 0.89 and 0.79 eV for un-doped and Mn 1 pct-doped ZnO films. Besides, schematic cross section of the Au/ n-ZnO/ n-Si/Al device and energy band diagram of n-ZnO/ n-Si heterojunction has been illustrated to clarify the transport mechanism. All results suggest that the characteristic properties of the ZnO thin films can be adjustable with the Mn doping and Al/ n-Si/ n-ZnO/Au diode can be used for UV detection application in photonic devices.

  16. High-capacity cathodes for lithium-ion batteries from nanostructured LiFePO4 synthesized by highly-flexible and scalable flame spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hamid, N. A.; Wennig, S.; Hardt, S.; Heinzel, A.; Schulz, C.; Wiggers, H.

    2012-10-01

    Olivine, LiFePO4 is a promising cathode material for lithium-ion batteries due to its low cost, environmental acceptability and high stability. Its low electric conductivity prevented it for a long time from being used in large-scale applications. Decreasing its particle size along with carbon coating significantly improves electronic conductivity and lithium diffusion. With respect to the controlled formation of very small particles with large specific surface, gas-phase synthesis opens an economic and flexible route towards high-quality battery materials. Amorphous FePO4 was synthesized as precursor material for LiFePO4 by flame spray pyrolysis of a solution of iron acetylacetonate and tributyl phosphate in toluene. The pristine FePO4 with a specific surface from 126-218 m2 g-1 was post-processed to LiFePO4/C composite material via a solid-state reaction using Li2CO3 and glucose. The final olivine LiFePO4/C particles still showed a large specific surface of 24 m2 g-1 and were characterized using X-ray diffraction (XRD), electron microscopy, X-ray photoelectron spectrocopy (XPS) and elemental analysis. Electrochemical investigations of the final LiFePO4/C composites show reversible capacities of more than 145 mAh g-1 (about 115 mAh g-1 with respect to the total coating mass). The material supports high drain rates at 16 C while delivering 40 mAh g-1 and causes excellent cycle stability.

  17. The electrical, optical, structural and thermoelectrical characterization of n- and p-type cobalt-doped SnO 2 transparent semiconducting films prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Bagheri-Mohagheghi, Mohammad-Mehdi; Shokooh-Saremi, Mehrdad

    2010-10-01

    The electrical, optical and structural properties of Cobalt (Co) doped SnO 2 transparent semiconducting thin films, deposited by the spray pyrolysis technique, have been studied. The SnO 2:Co films, with different Co-content, were deposited on glass substrates using an aqueous-ethanol solution consisting of tin and cobalt chlorides. X-ray diffraction studies showed that the SnO 2:Co films were polycrystalline only with tin oxide phases and preferential orientations along (1 1 0) and (2 1 1) planes and grain sizes in the range 19-82 nm. Optical transmittance spectra of the films showed high transparency ?75-90% in the visible region, decreasing with increase in Co-doping. The optical absorption edge for undoped SnO 2 films was found to be 3.76 eV, while for higher Co-doped films shifted toward higher energies (shorter wavelengths) in the range 3.76-4.04 eV and then slowly decreased again to 4.03 eV. A change in sign of the Hall voltage and Seebeck coefficient was observed for a specific acceptor dopant level ?11.4 at% in film and interpreted as a conversion from n-type to p-type conductivity. The thermoelectric electro-motive force (e.m.f.) of the films was measured in the temperature range 300-500 K and Seebeck coefficients were found in the range from -62 to +499 ?VK -1 for various Co-doped SnO 2 films.

  18. Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    DOEpatents

    Moore, Karen A. (Idaho Falls, ID); Zatorski, Raymond A. (East Hampton, CT)

    2007-10-02

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  19. Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    DOEpatents

    Moore, Karen A.; Zatorski, Raymond A.

    2005-07-12

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  20. Spray vaccination: a method for the immunization of fish

    USGS Publications Warehouse

    Gould, R.W.; O'Leary, P. J.; Garrison, R. L.; Rohovec, J.S.; Fryer, J.L.

    1978-01-01

    The use of immunizing agents is emerging as a complement to other methods of disease control and has been used successfully both experimentally and commercially (FRYER et al., 1977). Two problems exist in the development of fish vaccines: first, to provide efficacious preparations; and second, to provide economic methods for mass vaccination. Vaccines for fish have been delivered by several methods to include: parenteral injection; orally, through incorporation of vaccines into the animal's diet; hyperosmotic infiltration, by placing fish in a hyperosmotic solution followed by a vaccine bath; direct immersion into vaccine suspensions; or by direct addition of vaccine to water in which fish are held (CORBEL, 1975; AMEND, 1976; AMEND and FENDER, 1976; SCHACTE, 1976; ANTIPA and AMEND, 1977; CROY and AMEND, 1977; FRYER, et al., 1977). Each of these techniques has its inherent advantages and disadvantages. Although intraperitoneal injection appears to be most effective, this method is time consuming and stresses the fish being vaccinated. Oral administration is perhaps the most desirable method of vaccine delivery, but in some cases has not provided high levels of resistance (GUNNELS, et al., 1976). Hyperosmotic infil tration and direct immersion are used to vac cinate small fish but may not be economical with larger animals. Addition of vaccine to water has been used experimentally only with an attenuated viral vaccine (FRYER et al., 1976). This report describes another method for mass immunization of fish. A bacterin against Vibrio anguillarum was administered by spraying fish with antigens prepared by selected methods. This technique provided a fast efficacious means of administering vibrio bacterin. 

  1. Heat flux requirements for fast pyrolysis and a new method for generating biomass vapor

    SciTech Connect

    Reed, T.B.; Cowdery, C.D.

    1987-04-01

    The term ''fast pyrolysis'' has been used to describe a pyrolysis regime in which vapor production is enhanced and char minimized by rapid heating. It has been found in the last decade that high yields of primary pyrolysis oil can be achieved using fast pyrolysis. More recently it has been found that the pyrolysis vapors can be converted to high grade fuels using a catalyst. This makes fast pyrolysis of biomass desirable for synthetic fuel manufacture. The authors present results derived from the Diebold Integrated Kinetic Model (DKM) that predict the time, the temperature, and the products of pyrolysis and the heat for pyrolysis of cellulose as a function of heating rates between 0.01 and 10/sup 5/C/min. This range covers very slow pyrolysis requiring days to fast pyrolysis occurring in fractions of a second. The predictions are in good qualitative agreement with experimental measurements. They then compare the heat flux required for slow and fast pyrolysis for particles with that which can be obtained with practical heating devices. The comparison shows that convective and radiative heat transfer is adequate for fast pyrolysis of small particles, but not for large particles, due to conduction to the interior.

  2. Method and apparatus for heat extraction by controlled spray cooling

    DOEpatents

    Edwards, Christopher Francis (5492 Lenore Ave., Livermore, Alameda County, CA 94550); Meeks, Ellen (304 Daisyfield Dr., Livermore, Alameda County, CA 94550); Kee, Robert (864 Lucille St., Livermore, Alameda County, CA 94550); McCarty, Kevin (304 Daisyfield Dr., Livermore, Alameda County, CA 94550)

    1999-01-01

    Two solutions to the problem of cooling a high temperature, high heat flux surface using controlled spray cooling are presented for use on a mandrel. In the first embodiment, spray cooling is used to provide a varying isothermal boundary layer on the side portions of a mandrel by providing that the spray can be moved axially along the mandrel. In the second embodiment, a spray of coolant is directed to the lower temperature surface of the mandrel. By taking advantage of super-Leidenfrost cooling, the temperature of the high temperature surface of the mandrel can be controlled by varying the mass flux rate of coolant droplets. The invention has particular applicability to the field of diamond synthesis using chemical vapor deposition techniques.

  3. Investigating pyrolysis/incineration as a method of resource recovery from solid waste

    NASA Technical Reports Server (NTRS)

    Robertson, Bobby J.; Lemay, Christopher S.

    1993-01-01

    Pyrolysis/incineration (P/I) is a physicochemical method for the generation of recoverable resources from solid waste materials such as inedible plant biomass (IPB), paper, plastics, cardboard, etc. P/I permits the collection of numerous gases with a minimal amount of solid residue. Pyrolysis, also known as starved air incineration, is usually conducted at relatively high temperatures (greater than 500 deg C) in the absence of oxygen. Incineration is conducted at lower temperatures in the presence of oxygen. The primary purpose of this study was to design, construct, and test a model P/I. The system design includes safety requirements for temperature and pressure. The objectives of this study were: (1) to design and construct a P/I system for incorporation with the Hybrid Regenerative Water Recovery System; (2) to initiate testing of the P/I system; (3) to collect and analyze P/I system data; (4) to consider test variables; and (5) to determine the feasibility of P/I as an effective method of resource recovery. A P/I system for the recovery of reuseable resources from solid waste materials was designed, constructed, and tested. Since a large amount of inedible plant biomass (IPB) will be generated in a space-based habitat on the lunar surface and Mars, IPB was the primary waste material tested in the system. Analysis of the effluent gases was performed to determine which gases could be used in a life support system.

  4. Microstructural and electrochemical impedance study of nickel-Ce0.9Gd0.1O1.95 anodes for solid oxide fuel cells fabricated by ultrasonic spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Kim, Gap-Yong; Hillier, Andrew C.; Chandra, Abhijit

    2011-03-01

    Optimization of the electrode microstructure in a solid oxide fuel cell (SOFC) is an important approach to performance enhancement. In this study, the relationship between the microstructure and electrochemical performance of an anode electrode fabricated by ultrasonic spray pyrolysis was investigated. Nickel-Ce0.9Gd0.1O1.95 (Ni-CGO) anodes were deposited on a dense yttria stabilized zirconia (YSZ) substrate by ultrasonic spray pyrolysis, and the resulting microstructure was analyzed. Scanning electron microscope (SEM) examinations revealed the impact of deposition temperature and precursor solution concentration on anode morphology, particle size and porosity. The electrochemical performance of the anode was measured by electrochemical impedance spectroscopy (EIS) using a Ni-CGO/YSZ/Ni-CGO symmetrical cell. The deposited anode had a particle size and porosity in ranging between 1.5-17 ?m and 21%-52%, respectively. The estimated volume-specific triple phase boundary (TPB) length increased from 1.37 10-3 ?m ?m-3 to 1.77 10-1 ?m ?m-3as a result of decrease of the particle size and increase of the porosity. The corresponding area specific charge transfer resistance decreased from 5.45 ohm cm2 to 0.61 ohm cm2 and the activation energy decreased from 1.06 eV to 0.86 eV as the TPB length increased.

  5. Physical Fundamentals of the Novel Method of Nanoparticles Production by Low Pressure Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Fisenko, S. P.; Khodyko, J. A.; Penyazkov, O. G.; Saverchenko, V. I.

    2013-05-01

    Contributions of relevant heat and mass transfer processes and characteristic times in nanoparticles production during evaporation of droplet solution are discussed. Low-temperature transformation of aqueous solution of NiCl2 into nickel oxide nanoparticles is obtained. Classification of morphologies of obtained ensembles of nanoparticles is developed. Details of electrostatic deposition of droplets on metallic substrate are reported.

  6. Aerial application methods for increasing spray deposition on wheat heads

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) is a major disease of wheat and barley in several small grain production areas in the United States and, as such, the development and evaluation of aerial application technologies that enhance the efficacy of fungicides with aerial spray applications is critical to its man...

  7. Selective laser pyrolysis of metalorganics as a method of forming patterned thin-film superconductors

    SciTech Connect

    Mantese, J.V.; Catalan, A.B.; Mance, A.M.; Hamdi, A.H.; Micheli, A.L.; Sell, J.A.; Meyer, M.S.

    1988-10-03

    Fine line superconductors of Y-Ba-Cu-O were formed on <100> SrTiO/sub 3/ by the completely nonvacuum techniques of metalorganic deposition and selective laser pyrolysis. Lines 35 ..mu..m wide were written, using an Ar laser, in metal neodecanoates prior to pyrolysis. Regions of the metalorganics not exposed to laser pyrolysis were developed away using a xylene wash. Complete pyrolysis of the metal neodecanoates and rapid thermal annealing produced lines having superconducting onsets above 90 K and zero resistance at 69 K.

  8. Plasmochemical coal pyrolysis

    SciTech Connect

    Gebeker, D.; Mosse, A.L.; Ermolaeva, E.M.; Dvindenko, I.A.

    1987-11-01

    A study has been made on the pyrolysis of brown coals from a deposit in the GDR in a plasma reactor having a multijet mixing chamber and a hydrogen-plasma flow. The scope for implementing the pyrolysis is considered, together with the pros and cons of each of the methods. The process parameters have been related to the thermal and geometrical characteristics.

  9. Efficient planar perovskite solar cell by spray and brush solution-processing methods

    NASA Astrophysics Data System (ADS)

    Chilvery, Ashwith Kumar; Guggilla, Padmaja; Batra, Ashok K.; Gaikwad, Dyaneshwar D.; Currie, James R.

    2015-01-01

    Perovskite compounds have the potential to transform photovoltaics technology, as they are easy to fabricate, have better stability, and possess superior power conversion efficiency. In this research, a versatile solution-processing method called "spray+brush" (SB) has been adopted to achieve a power-conversion efficiency of 3.52% for pure organometal halide perovskite devices. It has been observed that this method is more efficient and cost effective than the perovskite devices fabricated by spray (1.95%) and brush (1.17%) methods alone. The SB method of solution processing can be promising for various other organic coatings.

  10. Facile water-based spray pyrolysis of earth-abundant Cu2FeSnS4 thin films as an efficient counter electrode in dye-sensitized solar cells.

    PubMed

    Prabhakar, Rajiv Ramanujam; Huu Loc, Nguyen; Kumar, Mulmudi Hemant; Boix, Pablo P; Juan, Sun; John, Rohit Abraham; Batabyal, Sudip K; Wong, Lydia Helena

    2014-10-22

    A novel approach to produce earth-abundant Cu2FeSnS4 (CFTS) thin film using spray pyrolysis of nontoxic aqueous precursors followed by sulfurization is reported. The CFTS phase formation was confirmed by both Raman spectroscopy and X-ray diffraction techniques. Hall measurements of these films reveal p-type conductivity with good charge carrier density and mobilities appropriate for solar harvesting devices. To the best of our knowledge, this is the first report on the electrical properties of solution-processed Cu2FeSnS4 thin films estimated using Hall measurements. Dye-sensitized solar cells (DSSC) fabricated with CFTS thin film as a photocathode in iodine/iodide electrolyte exhibit good power conversion efficiency, 8.03%, indicating that CFTS would be a promising cheaper alternative to replace Pt as a counter electrode in DSSCs. PMID:25255739

  11. Antibody immobilization using pneumatic spray: comparison with the avidin-biotin bridge immobilization method.

    PubMed

    Figueroa, Jhon; Magaa, Sonia; Lim, Daniel V; Schlaf, Rudy

    2012-12-14

    The formation of a thin antibody film on a glass surface using pneumatic spray was investigated as a potential immobilization technique for capturing pathogenic targets. Goat-Escherichia coli O157:H7 IgG films were made by pneumatic spray and compared against the avidin-biotin bridge immobilized films by assaying with green fluorescent protein (GFP) transformed E. coli O157:H7 cells and fluorescent reporter antibodies. Functionality, stability, and immobilization of the films were tested. The pneumatic spray films had lower fluorescence intensity values than the avidin-biotin bridge films but resulted in similar detection for E. coli O157:H7 at 10(5)-10(7)cells/ml sample concentrations with no detection of non-E. coli O157:H7 strains. Both methods also resulted in similar percent capture efficiencies. The results demonstrated that immobilization of antibody via pneumatic spray did not render the antibody non-functional and produced stable antibody films. The amount of time necessary for immobilization of the antibody was reduced significantly from 24h for the avidin-biotin bridge to 7 min using the pneumatic spray technique, with additional benefits of greatly reduced use of materials and chemicals. The pneumatic spray technique promises to be an alternative for the immobilization of antibodies on glass slides for capturing pathogenic targets and use in biosensor type devices. PMID:22955211

  12. Multiphase and Double-Layer NiFe2O4@NiO-Hollow-Nanosphere-Decorated Reduced Graphene Oxide Composite Powders Prepared by Spray Pyrolysis Applying Nanoscale Kirkendall Diffusion.

    PubMed

    Park, Gi Dae; Cho, Jung Sang; Kang, Yun Chan

    2015-08-01

    Multicomponent metal oxide hollow-nanosphere decorated reduced graphene oxide (rGO) composite powders are prepared by spray pyrolysis with nanoscale Kirkendall diffusion. The double-layer NiFe2O4@NiO-hollow-nanosphere decorated rGO composite powders are prepared using the first target material. The NiFe-alloy-nanopowder decorated rGO powders are prepared as an intermediate product by post-treatment under the reducing atmosphere of the NiFe2O4/NiO-decorated rGO composite powders obtained by spray pyrolysis. The different diffusion rates of Ni (83 pm for Ni(2+)) and Fe (76 pm for Fe(2+), 65 pm for Fe(3+)) cations with different radii during nanoscale Kirkendall diffusion result in multiphase and double-layer NiFe2O4@NiO hollow nanospheres. The mean size of the hollow NiFe2O4@NiO nanospheres decorated uniformly within crumpled rGO is 14 nm. The first discharge capacities of the nanosphere-decorated rGO composite powders with filled NiFe2O4/NiO and hollow NiFe2O4@NiO at a current density of 1 A g(-1) are 1168 and 1319 mA h g(-1), respectively. Their discharge capacities for the 100th cycle are 597 and 951 mA h g(-1), respectively. The discharge capacity of the NiFe2O4@NiO-hollow-nanosphere-decorated rGO composite powders at the high current density of 4 A g(-1) for the 400th cycle is 789 mA h g(-1). PMID:26186601

  13. In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

    PubMed Central

    Hamedi Rad, Fahimeh; Ghaffari, Tahereh; Safavi, Sayed Hamed

    2010-01-01

    Background and aims The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and De-conex) were selected and the impressions (n=108) were divided into four groups (n=24) and eight subgroups (n=12) for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12) was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were ana-lyzed by descriptive methods (mean and standard deviation), t-test, two-way analysis of variance (ANOVA) and Duncan test, using SPSS 14.0 software for windows. Results The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the im-mersion method, respectively. Conclusion Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10. PMID:23346340

  14. DEVELOPMENT OF PROPOSED STANDARD TEST METHOD FOR SPRAY PAINTING TRANSFER EFFICIENCY. VOLUME 2. VERIFICATION PROGRAM

    EPA Science Inventory

    The two-volume report gives results of a program to develop and verify a standardized spray-painting transfer-efficiency test method. Both review of the literature and laboratory research were conducted. Transfer efficiency measurement methods presently used by industry were eval...

  15. Spray cooling simulation implementing time scale analysis and the Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Kreitzer, Paul Joseph

    Spray cooling research is advancing the field of heat transfer and heat rejection in high power electronics. Smaller and more capable electronics packages are producing higher amounts of waste heat, along with smaller external surface areas, and the use of active cooling is becoming a necessity. Spray cooling has shown extremely high levels of heat rejection, of up to 1000 W/cm 2 using water. Simulations of spray cooling are becoming more realistic, but this comes at a price. A previous researcher has used CFD to successfully model a single 3D droplet impact into a liquid film using the level set method. However, the complicated multiphysics occurring during spray impingement and surface interactions increases computation time to more than 30 days. Parallel processing on a 32 processor system has reduced this time tremendously, but still requires more than a day. The present work uses experimental and computational results in addition to numerical correlations representing the physics occurring on a heated impingement surface. The current model represents the spray behavior of a Spraying Systems FullJet 1/8-g spray nozzle. Typical spray characteristics are indicated as follows: flow rate of 1.05x10-5 m3/s, normal droplet velocity of 12 m/s, droplet Sauter mean diameter of 48 microm, and heat flux values ranging from approximately 50--100 W/cm2 . This produces non-dimensional numbers of: We 300--1350, Re 750--3500, Oh 0.01--0.025. Numerical and experimental correlations have been identified representing crater formation, splashing, film thickness, droplet size, and spatial flux distributions. A combination of these methods has resulted in a Monte Carlo spray impingement simulation model capable of simulating hundreds of thousands of droplet impingements or approximately one millisecond. A random sequence of droplet impingement locations and diameters is generated, with the proper radial spatial distribution and diameter distribution. Hence the impingement, lifetime and interactions of the droplet impact craters are tracked versus time within the limitations of the current model. A comparison of results from this code to experimental results shows similar trends in surface behavior and heat transfer values. Three methods have been used to directly compare the simulation results with published experimental data, including: contact line length estimates, empirical heat transfer equation calculations, and non-dimensional Nusselt numbers. A Nusselt number of 55.5 was calculated for experimental values, while a Nu of 16.0 was calculated from the simulation.

  16. One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure

    NASA Technical Reports Server (NTRS)

    Amar, Adam J.; Blackwell, Ben F.; Edwards, Jack R.

    2007-01-01

    The development and verification of a one-dimensional material thermal response code with ablation is presented. The implicit time integrator, control volume finite element spatial discretization, and Newton's method for nonlinear iteration on the entire system of residual equations have been implemented and verified for the thermochemical ablation of internally decomposing materials. This study is a continuation of the work presented in "One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure" (AIAA-2006-2910), which described the derivation, implementation, and verification of the constant density solid energy equation terms and boundary conditions. The present study extends the model to decomposing materials including decomposition kinetics, pyrolysis gas flow through the porous char layer, and a mixture (solid and gas) energy equation. Verification results are presented for the thermochemical ablation of a carbon-phenolic ablator which involves the solution of the entire system of governing equations.

  17. Method and system including a double rotary kiln pyrolysis or gasification of waste material

    SciTech Connect

    McIntosh, Michael J.; Arzoumanidis, Gregory G.

    1997-01-01

    A method of destructively distilling an organic material in particulate form wherein the particulates are introduced through an inlet into one end of an inner rotating kiln ganged to and coaxial with an outer rotating kiln. The inner and outer kilns define a cylindrical annular space with the inlet being positioned in registry with the axis of rotation of the ganged kilns. During operation, the temperature of the wall of the inner rotary kiln at the inlet is not less than about 500.degree. C. to heat the particulate material to a temperature in the range of from about 200.degree. C. to about 900.degree. C. in a pyrolyzing atmosphere to reduce the particulate material as it moves from the one end toward the other end. The reduced particulates including char are transferred to the annular space between the inner and the outer rotating kilns near the other end of the inner rotating kiln and moved longitudinally in the annular space from near the other end toward the one end in the presence of oxygen to combust the char at an elevated temperature to produce a waste material including ash. Also, heat is provided which is transferred to the inner kiln. The waste material including ash leaves the outer rotating kiln near the one end and the pyrolysis vapor leaves through the particulate material inlet.

  18. A method and system including a double rotary kiln pyrolysis or gasification of waste material

    SciTech Connect

    McIntosh, M.J.; Arzoumanidis, G.G.

    1995-12-31

    A method is described for destructively distilling an organic material in particulate form wherein the particulates are introduced through an inlet into one end of an inner rotating kiln ganged to and coaxial with an outer rotating kiln. The inner and outer kilns define a cylindrical annular space with the inlet being positioned in registry with the axis of rotation of the ganged kilns. During operation, the temperature of the wall of the inner rotary kiln at the inlet is not less than about 500 C to heat the particulate material to a temperature in the range of from about 200 C to about 900 C in a pyrolyzing atmosphere to reduce the particulate material as it moves from the one end toward the other end. The reduced particulates including char are transferred to the annular space between the inner and the outer rotating kilns near the other end of the inner rotating kiln and moved longitudinally in the annular space from near the other end toward the one end in the presence of oxygen to combust the char at an elevated temperature to produce a waste material including ash. Also, heat is provided which is transferred to the inner kiln. The waste material including ash leaves the outer rotating kiln near the one end and the pyrolysis vapor leaves through the particulate material inlet.

  19. Method and system including a double rotary kiln pyrolysis or gasification of waste material

    SciTech Connect

    McIntosh, M.J.; Arzoumanidis, G.G.

    1997-09-02

    A method is described for destructively distilling an organic material in particulate form wherein the particulates are introduced through an inlet into one end of an inner rotating kiln ganged to and coaxial with an outer rotating kiln. The inner and outer kilns define a cylindrical annular space with the inlet being positioned in registry with the axis of rotation of the ganged kilns. During operation, the temperature of the wall of the inner rotary kiln at the inlet is not less than about 500 C to heat the particulate material to a temperature in the range of from about 200 C to about 900 C in a pyrolyzing atmosphere to reduce the particulate material as it moves from the one end toward the other end. The reduced particulates including char are transferred to the annular space between the inner and the outer rotating kilns near the other end of the inner rotating kiln and moved longitudinally in the annular space from near the other end toward the one end in the presence of oxygen to combust the char at an elevated temperature to produce a waste material including ash. Also, heat is provided which is transferred to the inner kiln. The waste material including ash leaves the outer rotating kiln near the one end and the pyrolysis vapor leaves through the particulate material inlet. 5 figs.

  20. Effect of gas flow swirling on coating deposition by the cold gas-dynamic spray method

    NASA Astrophysics Data System (ADS)

    Kiselev, S. P.; Kiselev, V. P.; Zaikovskii, V. N.

    2012-03-01

    The effect of gas flow swirling on the process of coating deposition onto a target by the cold gas-dynamic spray method is studied experimentally and numerically. Flow swirling is found to change the gas flow field and to reduce the gas flow rate under typical conditions of cold gas-dynamic spray. In a non-swirled flow, the shape of the deposited spot is similar to a sharp cone. In contrast, the deposited spot in a swirled flow is shaped as a crater without particles at the center of this crater. It is found that this effect is caused by centrifugal forces acting on particles in a swirled gas flow.

  1. A Method for Characterizing the Degree of Inter-particle Bond Formation in Cold Sprayed Coatings

    NASA Astrophysics Data System (ADS)

    Price, T. S.; Shipway, P. H.; McCartney, D. G.; Calla, E.; Zhang, D.

    2007-12-01

    The degree of bonding between particles within cold-sprayed deposits is of great importance as it affects their mechanical and physical properties. This article describes a method for characterizing the bonding between aluminum and copper particles following deposition by cold spraying. Aluminum and copper powders were blended in the ratio 1:1 by volume, deposited onto a copper substrate and subsequently heat treated at 400 C for 15 min. An intermetallic layer formed along some regions of the aluminum-copper boundaries, believed to be where true metal to metal contact had occurred. In other regions, metal to metal contact was inhibited by the presence of oxide films. Image analysis was employed to measure the fraction of the aluminum-copper interface covered with intermetallic phases and to estimate intermetallic thicknesses. By increasing the primary gas pressure in the cold-spray process, an increase in the degree of inter-particle bond formation was observed.

  2. Spray atomization and combustion

    NASA Technical Reports Server (NTRS)

    Faeth, G. M.

    1986-01-01

    New theoretical and experimental methods for studying sprays are reviewed. Common methods to analyze dilute sprays are described and used to interpret recent measurements of the structure of dilute sprays and related dispersed turbulent jets. Particle-laden jets, nonevaporating, evaporating, and combusting sprays, and noncondensing and condensing bubbly jets are examined and used to initially evaluate current analytical methods for a wide range of conditions. Dense sprays are briefly discussed.

  3. Numerical simulation of spray coalescence in an Eulerian framework: Direct quadrature method of moments and multi-fluid method

    SciTech Connect

    Fox, R.O.; Laurent, F. Massot, M.

    2008-03-01

    The scope of the present study is Eulerian modeling and simulation of polydisperse liquid sprays undergoing droplet coalescence and evaporation. The fundamental mathematical description is the Williams spray equation governing the joint number density function f(v,u;x,t) of droplet volume and velocity. Eulerian multi-fluid models have already been rigorously derived from this equation in Laurent et al. [F. Laurent, M. Massot, P. Villedieu, Eulerian multi-fluid modeling for the numerical simulation of coalescence in polydisperse dense liquid sprays, J. Comput. Phys. 194 (2004) 505-543]. The first key feature of the paper is the application of direct quadrature method of moments (DQMOM) introduced by Marchisio and Fox [D.L. Marchisio, R.O. Fox, Solution of population balance equations using the direct quadrature method of moments, J. Aerosol Sci. 36 (2005) 43-73] to the Williams spray equation. Both the multi-fluid method and DQMOM yield systems of Eulerian conservation equations with complicated interaction terms representing coalescence. In order to focus on the difficulties associated with treating size-dependent coalescence and to avoid numerical uncertainty issues associated with two-way coupling, only one-way coupling between the droplets and a given gas velocity field is considered. In order to validate and compare these approaches, the chosen configuration is a self-similar 2D axisymmetrical decelerating nozzle with sprays having various size distributions, ranging from smooth ones up to Dirac delta functions. The second key feature of the paper is a thorough comparison of the two approaches for various test-cases to a reference solution obtained through a classical stochastic Lagrangian solver. Both Eulerian models prove to describe adequately spray coalescence and yield a very interesting alternative to the Lagrangian solver. The third key point of the study is a detailed description of the limitations associated with each method, thus giving criteria for their use as well as for their respective efficiency.

  4. Effect of pyrolysis temperature on the properties of carbon/nickel nanocomposites prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Mansour, N. Ben; Najeh, I.; Mansouri, S.; El Mir, L.

    2015-05-01

    Carbon-nickel nanocomposites (C/Ni) were prepared by sol-gel method after the incorporation of nickel oxide (NiO) nanoparticles in organic matrix based on pyrogallol-formaldehyde (PF). The nanocomposites heated under inert atmosphere have been characterized by various techniques such as X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and electrical analysis. The XRD spectra exhibited the presence of NiO or metallic Ni phase in amorphous carbon matrix at low pyrolysis temperature, while at 1000 C the graphite structure line was observed. The TEM images indicate the presence of multiwall carbon nanotubes (MWNT) around Ni nanoparticles for the sample treated at high pyrolysis temperature. The AC conductance shows that our nanocomposites have two behaviors: semiconductor and metal, depending on the pyrolysis temperature. The voltage-current V(I) characteristics of the compound show two different regions: an Ohmic region at low current and a negative differential resistance (NDR) region at higher current. This switching phenomenal behavior has been explained by an electrothermal model.

  5. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    NASA Technical Reports Server (NTRS)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  6. Confined-pyrolysis as an experimental method for hydrothermal organic synthesis

    NASA Astrophysics Data System (ADS)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-10-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  7. Methods for detecting the mobility of trace elements during medium-temperature pyrolysis

    USGS Publications Warehouse

    Shiley, R.H.; Konopka, K.L.; Cahill, R.A.; Hinckley, C.C.; Smith, Gerard V.; Twardowska, H.; Saporoschenko, Mykola

    1983-01-01

    The mobility (volatility) of trace elements in coal during pyrolysis has been studied for distances of up to 40 cm between the coal and the trace element collector, which was graphite or a baffled solvent trap. Nineteen elements not previously recorded as mobile were detected. ?? 1983.

  8. Formate-assisted pyrolysis

    DOEpatents

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.

    2015-03-17

    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  9. The feasibility study of hot cell decontamination by the PFC spray method

    SciTech Connect

    Hui-Jun Won; Chong-Hun Jung; Jei-Kwon Moon

    2008-01-15

    The characteristics of per-fluorocarbon compounds (PFC) are colorless, non-toxic, easily vaporized and nonflammable. Also, some of them are liquids of a high density, low surface tension, low latent heat and low specific heat. These particular chemical and physical properties of fluoro-organic compounds permit their use in very different fields such as electronics, medicine, tribology, nuclear and material science. The Sonatol process was developed under a contract with the DOE. The Sonatol process uses an ultrasonic agitation in a PFC solution that contains a fluorinated surfactant to remove radioactive particles from surfaces. Filtering the suspended particles allows the solutions to be reused indefinitely. They applied the Sonatol process to the decontamination of a heterogeneous legacy Pu-238 waste that exhibited an excessive hydrogen gas generation, which prevents a transportation of such a waste to a Waste Isolation Pilot Plant. Korea Atomic Energy Research Institute (KAERI) is developing dry decontamination technologies applicable to a decontamination of a highly radioactive area loosely contaminated with radioactive particles. This contamination has occurred as a result of an examination of a post-irradiated material or the development of the DUPIC process. The dry decontamination technologies developed are the carbon dioxide pellet spray method and the PFC spray method. As a part of the project, PFC ultrasonic decontamination technology was developed in 2004. The PFC spray decontamination method which is based on the test results of the PFC ultrasonic method has been under development since 2005. The developed PFC spray decontamination equipment consists of four modules (spray, collection, filtration and distillation). Vacuum cup of the collection module gathers the contaminated PFC solution, then the solution is moved to the filtration module and it is recycled. After a multiple recycling of the spent PFC solution, it is purified in the distillation module. A performance test on each module was executed and the results have been reported. A combined test of the four modules, however, has not been performed as yet. The main objective of the present study is to demonstrate the feasibility of the full PFC spray decontamination process. Decontamination of the inside of the IMEF hot cell by the PFC spray method was also performed. PFC spray decontamination process was demonstrated by using a surrogate wall contaminated with Eu{sub 2}O{sub 3} powder. The spray pressure was 41 kgf/cm{sup 2}, the orifice diameter was 0.2 mm and the spray velocity was 0.2 L/min. And, the decontaminated area was 100 cm{sup 2}. From previous test results, we found that the decontamination factor of the PFC spray method was in the range from 9.6 to 62.4. When the decontamination efficiency of Co-60 was high, then the decontamination efficiency of Cs-137 was also high. As the surface roughness of the specimen increased, the PFC spray decontamination efficiency decreased. Inferring from the previous results, the surface of the surrogate wall was cleaned by the PFC spray method. The vacuum cup of the collection module operated well and gathered more than 99 % of the PFC solution. Also, filtration and distillation modules operated well. All the filtered PFC solution flowed to the storage chamber where some of the PFC solution was distilled. The coolant of the distillation module was a dry ice. And, the recycled solution was transferred to the spray module by a high pressure pump. To evaluate the PFC spray decontamination efficiency, a smear device was fabricated and operated by a manipulator. Before and after decontamination, a smear test was performed. The tested area was 100 cm{sup 2} and the radioactivity was estimated indirectly by measuring the radioactivity of the filter paper. The average decontamination factor was in the range between 10 and 15. One application time was 2 minutes. The sprayed PFC solution was collected by the vacuum cup and it was stored in the collection equipment. After the termination of the decontamination test, th

  10. δ18O analysis of individual carbohydrates - a new method for GC-pyrolysis-IRMS

    NASA Astrophysics Data System (ADS)

    Lehmann, Marco M.; Fischer, Maria; Zech, Michael; Siegwolf, Rolf T. W.; Saurer, Matthias

    2015-04-01

    Measuring the oxygen isotopic composition (δ18O) of various plant tissues is a widely used tool to investigate biochemical and physiological processes. While we have a good understanding about the hydrological cycle in plants with an evaporative enrichment in 18O in leaf water, we still lack knowledge about the biochemical link between the oxygen atoms in leaf water, leaf assimilates, and stem cellulose and associated isotope fractionations. Especially, the influence of different environmental factors on δ18O of individual carbohydrates (i.e. sugars) and thus on δ18O of cellulose is not fully resolved. A better understanding of these processes may improve climatic reconstructions of tree-ring studies about past environmental conditions. However, further progress in this topic is limited since a precise and reliable method to determine δ18O of individual sugars has not been available yet. With our new approach we attempt to overcome this issue by establishing a new methylation derivatization method suitable for GC-pyrolysis -IRMS. A methyl group (CH3) was thereby added to all hydroxyl groups of a sugar (e.g., glucose, fructose, and sucrose) during a catalyzed one-pot reaction overnight in acetonitrile with methyl iodide (CH3-I) and silver oxide, making them amenable for GC analysis. First results show a very good precision for δ18O of sucrose, but also δ18O of other high-abundant sugars such as glucose and fructose could be measured for the first time. We successfully analyzed a standard mix of all three sugars and determined various other carbohydrates not only related to plant sciences (e.g. mannitol, lactose), showing promising δ18O results. First tests with real plant samples were performed to make this method available for determining δ18O of individual carbohydrates of diverse plant tissues. In future, this new methylation derivatization method should allow us analyzing plant samples of different field sites and of lab experiments to investigate the link between leaf sugars and stem cellulose, as well as the influence of environmental factors on δ18O of individual carbohydrates in plants, but may be applied also in other research fields working on food quality or on medical applications.

  11. Analytical methods to characterize heterogeneous raw material for thermal spray process: cored wire Inconel 625

    NASA Astrophysics Data System (ADS)

    Lindner, T.; Bonebeau, S.; Drehmann, R.; Grund, T.; Pawlowski, L.; Lampke, T.

    2016-03-01

    In wire arc spraying, the raw material needs to exhibit sufficient formability and ductility in order to be processed. By using an electrically conductive, metallic sheath, it is also possible to handle non-conductive and/or brittle materials such as ceramics. In comparison to massive wire, a cored wire has a heterogeneous material distribution. Due to this fact and the complex thermodynamic processes during wire arc spraying, it is very difficult to predict the resulting chemical composition in the coating with sufficient accuracy. An Inconel 625 cored wire was used to investigate this issue. In a comparative study, the analytical results of the raw material were compared to arc sprayed coatings and droplets, which were remelted in an arc furnace under argon atmosphere. Energy-dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) analysis were used to determine the chemical composition. The phase determination was performed by X-ray diffraction (XRD). The results were related to the manufacturer specifications and evaluated in respect to differences in the chemical composition. The comparison between the feedstock powder, the remelted droplets and the thermally sprayed coatings allows to evaluate the influence of the processing methods on the resulting chemical and phase composition.

  12. NDE Methods for the External Tank Spray on Foam Insulation

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Johnson, Kenneth L.; Santos, Fernando E.; Ussery, W. Warren

    2007-01-01

    The foam thermal protection system (TPS) of the space shuttle External Tank (ET) has provided some unique challenges to the nondestructive testing community. Three nondestructive evaluation methods have been developed to identify defects in the foam TPS of the ET. Terahertz imaging and backscatter radiography have been developed to identify voids in thick foam regions while shearography has been developed to identify shallow delaminations, shallow voids and crush damage in the foam. The basic theory of operation along with factors, determined from a series of designed experiments, affecting the results of these methods will be described. Results from both test panels and flight tank inspections will be provided, along with predicted probability of detection estimates to show the range in defect sizes and types that can be readily detected.

  13. Numerical Modeling of Spray Combustion with an Unstructured-Grid Method

    NASA Technical Reports Server (NTRS)

    Shang, H. M.; Chen, Y. S.; Liaw, P.; Shih, M. H.; Wang, T. S.

    1996-01-01

    The present unstructured-grid method follows strictly the basic finite volume forms of the conservation laws of the governing equations for the entire flow domain. High-order spatially accurate formulation has been employed for the numerical solutions of the Navier-Stokes equations. A two-equation k-epsilon turbulence model is also incorporated in the unstructured-grid solver. The convergence of the resulted linear algebraic equation is accelerated with preconditioned Conjugate Gradient method. A statistical spray combustion model has been incorporated into the present unstructured-grid solver. In this model, spray is represented by discrete particles, rather than by continuous distributions. A finite number of computational particles are used to predict a sample of total population of particles. Particle trajectories are integrated using their momentum and motion equations and particles exchange mass, momentum and energy with the gas within the computational cell in which they are located. The interaction calculations are performed simultaneously and eliminate global iteration for the two-phase momentum exchange. A transient spray flame in a high pressure combustion chamber is predicted and then the solution of liquid-fuel combusting flow with a rotating cup atomizer is presented and compared with the experimental data. The major conclusion of this investigation is that the unstructured-grid method can be employed to study very complicated flow fields of turbulent spray combustion. Grid adaptation can be easily achieved in any flow domain such as droplet evaporation and combustion zone. Future applications of the present model can be found in the full three-dimensional study of flow fields of gas turbine and liquid propulsion engine combustion chambers with multi-injectors.

  14. Response surface method for evaluation of the performance of agricultural application spray nozzles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Droplet size, being one of the critical factors that influences spray performance and drift, must be considered when selecting spray nozzles and operational setups. Characterizing a spray nozzle for droplet size is typically completed by evaluating arbitrary nozzle type, size and spray pressure. H...

  15. Apparatus and method for flotation separation utilizing an improved spiral spray nozzle

    SciTech Connect

    McGarry, P.E.; Fistner, D.C. Jr.; Herman, D.E.; Treskot, R.A.

    1985-04-30

    An improved method and apparatus for froth flotation separation of the components of a slurry, having particular utility for the beneficiation of coal by the flotation separation of coal particles from impurities associated therewith, such as ash and sulfur. In this arrangement, an improved open flow, spiral nozzle is positioned above a flotation tank having a bath therein, and sprays an input slurry through an aeration zone into the surface of the water. The spraying operation creates a froth on the water surface in which a substantial quantity of particulate matter floats, while other components of the slurry sink into the water bath. A skimming arrangement skims the froth from the water surface as a cleaned or beneficiated product.

  16. Rapid tooling from protoypes: the cool-spray mold-making method

    NASA Astrophysics Data System (ADS)

    Peres, Francois; Mofakhami, Arthur

    1998-10-01

    We propose in the paper a process, based on the use of a high velocity, electric arc metal spray thoroughly atomized on a master model in order to make a shell. The mold is realized by placing the sprayed alloy into a frame and reinforcing it with appropriate material. The first part of the paper presents briefly the main rapid prototyping and tooling techniques used in industry. We then describe the tool/moldmaking method which is a process to reproduce shapes very accurately. Given any model, a metal shell can be build up around it to desired thickness. We describe and comment the tasks leading to the shell making. The realization of the mold itself is also presented. In most cases, the spray alloy shell must be reinforced with backup. We expose the application fields of this new technique especially in term of product and process validation. We focus on the natural links with stereolithography. By comparison with conventional processes, we show how fabrication time and costs are dramatically reduced by integration of this new moldmaking method. Finally, we present the limits of the technique and the perspective of work and further research.

  17. Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.

    PubMed

    Henkel, S; Beyrau, F; Hardalupas, Y; Taylor, A M K P

    2016-02-01

    This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated. PMID:26906828

  18. Method and Process Development of Advanced Atmospheric Plasma Spraying for Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Mihm, Sebastian; Duda, Thomas; Gruner, Heiko; Thomas, Georg; Dzur, Birger

    2012-06-01

    Over the last few years, global economic growth has triggered a dramatic increase in the demand for resources, resulting in steady rise in prices for energy and raw materials. In the gas turbine manufacturing sector, process optimizations of cost-intensive production steps involve a heightened potential of savings and form the basis for securing future competitive advantages in the market. In this context, the atmospheric plasma spraying (APS) process for thermal barrier coatings (TBC) has been optimized. A constraint for the optimization of the APS coating process is the use of the existing coating equipment. Furthermore, the current coating quality and characteristics must not change so as to avoid new qualification and testing. Using experience in APS and empirically gained data, the process optimization plan included the variation of e.g. the plasma gas composition and flow-rate, the electrical power, the arrangement and angle of the powder injectors in relation to the plasma jet, the grain size distribution of the spray powder and the plasma torch movement procedures such as spray distance, offset and iteration. In particular, plasma properties (enthalpy, velocity and temperature), powder injection conditions (injection point, injection speed, grain size and distribution) and the coating lamination (coating pattern and spraying distance) are examined. The optimized process and resulting coating were compared to the current situation using several diagnostic methods. The improved process significantly reduces costs and achieves the requirement of comparable coating quality. Furthermore, a contribution was made towards better comprehension of the APS of ceramics and the definition of a better method for future process developments.

  19. Numerical analysis of partially molten splat during thermal spray process using the finite element method

    NASA Astrophysics Data System (ADS)

    Zirari, M.; Abdellah El-Hadj, A.; Bacha, N.

    2010-03-01

    A finite element method is used to simulate the deposition of the thermal spray coating process. A set of governing equations is solving by a volume of fluid method. For the solidification phenomenon, we use the specific heat method (SHM). We begin by comparing the present model with experimental and numerical model available in the literature. In this study, completely molten or semi-molten aluminum particle impacts a H13 tool steel substrate is considered. Next we investigate the effect of inclination of impact of a partially molten particle on flat substrate. It was found that the melting state of the particle has great effects on the morphologies of the splat.

  20. Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Jabena Begum, N.; Mohan, R.; Ravichandran, K.

    2013-01-01

    Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

  1. Recent advances in nanoparticle preparation by spray and micro-emulsion methods.

    PubMed

    Eslamian, Morteza; Shekarriz, Marzieh

    2009-01-01

    Micro- and nano-sized metal, semiconductor, pharmaceutical, and simple or complex ceramic particles have numerous applications in the development of sensors, thermal barrier coatings, catalysts, pigments, drugs, etc. The challenges include controlling the particle size, size distribution, particle crystallinity, morphology and shape, being able to use the nanoparticles for a given purpose, and to produce them from a variety of precursors. There are several methods to produce nanoparticles, each suitable for a range of applications. In this article, two methods that are receiving increasing attention are considered: spray and microemulsion methods. Spray techniques are single-step methods of producing a broad spectrum of simple to multicomponent functional micro and nanoparticles and quantum dots. Microemulsion is a wet chemistry method. A micro-emulsion system consists of aqueous domains, called reverse micelles, dispersed in a continuous oil phase. In this article, the above mentioned methods of nanoparticle production are introduced and recent advances, research directions and challenges, and the pertinent patents are reviewed and discussed. PMID:19519594

  2. Effect of boric acid on the properties of Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders prepared by large-scale spray pyrolysis with droplet classifier

    SciTech Connect

    Hong, Young Jun; Choi, Seung Ho; Sim, Chul Min; Lee, Jung-Kul; Kang, Yun Chan

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Spherical shape Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders are prepared by large-scale spray pyrolysis with droplet classifier. ► Boric acid improves the morphological and electrochemical properties of the composite cathode powders. ► The discharge capacity of the composite cathode powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle. -- Abstract: Spherically shaped 0.3Li{sub 2}MnO{sub 3}·0.7LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders with filled morphology and narrow size distribution are prepared by large-scale spray pyrolysis. A droplet classification reduces the standard deviation of the size distribution of the composite cathode powders. Addition of boric acid improves the morphological properties of the product powders by forming a lithium borate glass material with low melting temperature. The optimum amount of boric acid dissolved in the spray solution is 0.8 wt% of the composite powders. The powders prepared from the spray solution with 0.8 wt% boric acid have a mixed layered crystal structure comprising Li{sub 2}MnO{sub 3} and LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} phases, thus forming a composite compound. The initial charge and discharge capacities of the composite cathode powders prepared from the 0.8 wt% boric acid spray solution are 297 and 217 mAh g{sup −1}, respectively. The discharge capacity of the powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle, in which the capacity retention is 90%.

  3. Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets

    NASA Technical Reports Server (NTRS)

    Derochemont, L. Pierre; Zhang, John G.; Squillante, Michael R.; Hermann, A. M.; Duan, H. M.; Andrews, Robert J.; Kelliher, Warren C.

    1991-01-01

    The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed.

  4. Method and Apparatus for Thermal Spraying of Metal Coatings Using Pulsejet Resonant Pulsed Combustion

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E. (Inventor)

    2014-01-01

    An apparatus and method for thermal spraying a metal coating on a substrate is accomplished with a modified pulsejet and optionally an ejector to assist in preventing oxidation. Metal such as Aluminum or Magnesium may be used. A pulsejet is first initiated by applying fuel, air, and a spark. Metal is inserted continuously in a high volume of metal into a combustion chamber of the pulsejet. The combustion is thereafter controlled resonantly at high frequency and the metal is heated to a molten state. The metal is then transported from the combustion chamber into a tailpipe of said pulsejet and is expelled therefrom at high velocity and deposited on a target substrate.

  5. Study of Surface Cleaning Methods and Pyrolysis Temperature on Nano-Structured Carbon Films using X-ray Photoelectron Spectroscopy

    SciTech Connect

    Kerber, Pranita B.; Porter, Lisa M.; McCullough, L. A.; Kowalewski, Tomasz; Engelhard, Mark H.; Baer, Donald R.

    2012-10-12

    Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of di-block copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, (2009) 177]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of di-block copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) (PAN-b-PBA) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included: HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % of nitrogen present in the films pyrolyzed at 600 °C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration reduced significantly for films pyrolyzed at 900 °C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen sub-peaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic cluster, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 °C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.

  6. Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy

    SciTech Connect

    Kerber, Pranita; Porter, Lisa M.; McCullough, Lynne A.; Kowalewski, Tomasz; Engelhard, Mark; Baer, Donald

    2012-11-15

    Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 Degree-Sign C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 Degree-Sign C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 Degree-Sign C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.

  7. Effect of antimicrobials applied on the surface of beef subprimals via an air-assisted electrostatic spraying system(ESS)or the Sprayed Lethality in Container(SLIC)method to control Shiga toxin-producing cells of Escherichia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the efficacy of an air-assisted electrostatic spraying system (ESS) and/or the Sprayed Lethality in Container (SLIC) method to deliver antimicrobials onto the surface of beef subprimals to reduce levels of Shiga toxin-producing cells of Escherichia coli (STEC). In brief, beef subprimal...

  8. Molecular characterization and comparison of shale oils generated by different pyrolysis methods using FT-ICR mass spectrometry

    USGS Publications Warehouse

    Jin, J.M.; Kim, S.; Birdwell, J.E.

    2011-01-01

    Fourier transform ion cyclotron resonance mass spectrometry (FT ICR-MS) was applied in the analysis of shale oils generated using two different pyrolysis systems under laboratory conditions meant to simulate surface and in situ oil shale retorting. Significant variations were observed in the shale oils, particularly the degree of conjugation of the constituent molecules. Comparison of FT ICR-MS results to standard oil characterization methods (API gravity, SARA fractionation, gas chromatography-flame ionization detection) indicated correspondence between the average Double Bond Equivalence (DBE) and asphaltene content. The results show that, based on the average DBE values and DBE distributions of the shale oils examined, highly conjugated species are enriched in samples produced under low pressure, high temperature conditions and in the presence of water.

  9. Alternative methods for herbicide spray drift detection in corn and cotton

    NASA Astrophysics Data System (ADS)

    Buehring, Nathan Wade

    The acceptance of herbicide-resistant crops and the subsequent increase in glyphosate use throughout the growing season has led to increased problems with herbicide drift in corn and cotton. Potential yield losses due to herbicide spray drift cannot always be accurately assessed using visual ratings or by measuring reductions in plant height. This research was conducted to determine if other methods, such as biochemical assays or remote sensing, could be used to assess potential yield reductions and visual injury associated with herbicide drift. Other objectives included using hyperspectral and multispectral remote sensing for herbicide drift detection in corn and cotton. Classification accuracies were highest 14 DAA when distinguishing untreated from treated corn. When the data were classified by herbicides, overall accuracies of ?74% resulted 14 and 28 DAA. Classifications based on yield reduction also resulted in highest overall classification accuracies 14 and 28 DAA, ranging from 69 to 70%. Within the glufosinate-treated corn, overall accuracies for classifying percent yield reductions was 85% at 3 DAA and decreased to 68% at 28 DAA. Overall classification accuracies for determining percent yield reductions with glyphosate were higher 14 and 28 DAA. With pyrithiobac, overall accuracies for determining percent yield reductions ranged from 73 to 82% across all evaluations. Of the nine vegetative indices tested to classify the data, Anthocyanin Reflective Index (ARI) and Chlorophyll Fluorescence Ratio of reflectance at 735 nm/700 nm (CF 735) were the most important for classifying, assessing, and detecting herbicide spray drift in corn. Multispectral aerial imagery was also used to identify cotton affected by a simulated bromoxynil drift event. Multispectral aerial imagery collected 9 DAA in 2002 resulted in better classification accuracies for identifying bromoxynil rate, percent visual injury, and percent yield reduction than imagery collected 21 DAA in 2001. The results from this research indicate that bromoxynil spray drift could be detected with multispectral aerial imagery. However, the images would need to be collected soon (9 DAA) after the drift event occurred. (Abstract shortened by UMI.)

  10. The Effect of Three Different Disinfection Materials on Alginate Impression by Spray Method

    PubMed Central

    Badrian, Hamid; Ghasemi, Ehsan; Khalighinejad, Navid; Hosseini, Nafiseh

    2012-01-01

    Introduction. The aim of this study was to investigate the effect of three different types of disinfectant agents on alginate impression material after 5 and 10 minutes. Method and Materials. In this in vitro experimental study, 66 circular samples of alginate impression material were contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans fungus. Except for control samples, all of them were disinfected with sodium hypochlorite 0.525, Deconex, and Epimax by way of spraying. Afterwards, they were kept in plastic bags with humid rolled cotton for 5 and 10 minutes. The number of colonies was counted after 24 and 48 hours for bacteria and after 72 hours for fungus. Statistical Mann-Whitney test was used for data analysis (? = 0.05). Results. After 5 minutes, Epimax showed the highest disinfection action on Staphylococcus aureus as it completely eradicated the bacteria. The disinfection capacity of different agents can be increased as time elapses except for Pseudomonas aeruginosa which was eradicated completely in both 5 and 10 minutes. Conclusion. This study revealed that alginate can be effectively disinfected by three types of disinfecting agents by spraying method, although Epimax showed the highest disinfection action after 10 minutes compared to other agents. PMID:22900196

  11. Deposition of titanium nitride layers by electric arc - Reactive plasma spraying method

    NASA Astrophysics Data System (ADS)

    Şerban, Viorel-Aurel; Roşu, Radu Alexandru; Bucur, Alexandra Ioana; Pascu, Doru Romulus

    2013-01-01

    Titanium nitride (TiN) is a ceramic material which possesses high mechanical properties, being often used in order to cover cutting tools, thus increasing their lifetime, and also for covering components which are working in corrosive environments. The paper presents the experimental results on deposition of titanium nitride coatings by a new combined method (reactive plasma spraying and electric arc thermal spraying). In this way the advantages of each method in part are combined, obtaining improved quality coatings in the same time achieving high productivity. Commercially pure titanium wire and C45 steel as substrate were used for experiments. X-ray diffraction analysis shows that the deposited coatings are composed of titanium nitride (TiN, Ti2N) and small amounts of Ti3O. The microstructure of the deposited layers, investigated both by optical and scanning electron microscopy, shows that the coatings are dense, compact, without cracks and with low porosity. Vickers microhardness of the coatings presents maximum values of 912 HV0.1. The corrosion tests in 3%NaCl solution show that the deposited layers have a high corrosion resistance compared to unalloyed steel substrate.

  12. Use of pyrolysis molecular beam mass spectrometry (py-MBMS) to characterize forest soil carbon: method and preliminary results.

    PubMed

    Magrini, K A; Evans, R J; Hoover, C M; Elam, C C; Davis, M F

    2002-01-01

    The components of soil organic matter (SOM) and their degradation dynamics in forest soils are difficult to study and thus poorly understood, due to time-consuming sample collection, preparation, and difficulty of analyzing and identifying major components. As a result, changes in soil organic matter chemical composition as a function of age, forest type, or disturbance have not been examined. We applied pyrolysis molecular beam mass spectrometry (py-MBMS), which provides rapid characterization of SOM of whole soil samples. to the Tionesta soil samples described by Hoover, C.M., Magrini, K.A., Evans, R.J., 2002. Soil carbon content and character in an old growth forest in northwestern Pennsylvania: a case study introducing molecular beam mass spectrometry (PY-MBMS). Environmental Pollution 116 (Supp. 1), S269-S278. Our goals in this work were to: (1) develop and demonstrate an advanced, rapid analytical method for characterizing SOM components in whole soils, and (2) provide data-based models to predict soil carbon content and residence time from py-MBMS analysis. Using py-MBMS and pattern recognition techniques we were able to statistically distinguish among four Tionesta sites and show an increase in pyrolysis products of more highly decomposed plant materials at increasing sample depth. For example, all four sites showed increasing amounts of older carbon (phenolic and aromatic species) at deeper depths and higher amounts of more recent carbon (carbohydrates and lignin products) at shallower depths. These results indicate that this type of analysis could be used to rapidly characterize SOM for the purpose of developing a model, which could be used in monitoring the effect of forest management practices on carbon uptake and storage. PMID:11833912

  13. Anisotropic Mechanical Properties of Plasma-Sprayed Thermal Barrier Coatings at High Temperature Determined by Ultrasonic Method

    NASA Astrophysics Data System (ADS)

    Wei, Qin; Zhu, Jianguo; Chen, Wei

    2016-01-01

    The mechanical properties of plasma-sprayed thermal barrier coatings (TBC) are of great scientific and technological significance for the design and fabrication of TBC systems. The ultrasonic method combined with a sing-around method for mechanical properties measurement of TBC is deduced and the elastic modulus can be determined in the spray, or longitudinal, direction, and the transverse direction. Tested specimens of plasma-sprayed TBC are detached from the substrate and treated with thermal exposure at 1400 °C. The elastic moduli along the longitudinal and transverse directions of the TBCs are measured by different types of ultrasonic waves combined with a sing-around method, while the Poisson's ratio is also obtained simultaneously. The experimental results indicate that the magnitude of longitudinal elastic modulus is larger than that of the transverse one, and thus the plasma-sprayed TBC has an anisotropic mechanical property. Moreover, the elastic moduli along both longitudinal and transverse directions change with high-temperature exposure time, which consists of a rapid increasing stage followed by a slow decreasing stage. In addition, the magnitude of Poisson's ratio increases slightly from 0.05 to 0.2 with the high-temperature exposure time. Generally, the microstructures in the plasma-sprayed coatings and their evolution in a high-temperature environment are the main causes of the varying anisotropic mechanical properties.

  14. Anisotropic Mechanical Properties of Plasma-Sprayed Thermal Barrier Coatings at High Temperature Determined by Ultrasonic Method

    NASA Astrophysics Data System (ADS)

    Wei, Qin; Zhu, Jianguo; Chen, Wei

    2016-02-01

    The mechanical properties of plasma-sprayed thermal barrier coatings (TBC) are of great scientific and technological significance for the design and fabrication of TBC systems. The ultrasonic method combined with a sing-around method for mechanical properties measurement of TBC is deduced and the elastic modulus can be determined in the spray, or longitudinal, direction, and the transverse direction. Tested specimens of plasma-sprayed TBC are detached from the substrate and treated with thermal exposure at 1400 °C. The elastic moduli along the longitudinal and transverse directions of the TBCs are measured by different types of ultrasonic waves combined with a sing-around method, while the Poisson's ratio is also obtained simultaneously. The experimental results indicate that the magnitude of longitudinal elastic modulus is larger than that of the transverse one, and thus the plasma-sprayed TBC has an anisotropic mechanical property. Moreover, the elastic moduli along both longitudinal and transverse directions change with high-temperature exposure time, which consists of a rapid increasing stage followed by a slow decreasing stage. In addition, the magnitude of Poisson's ratio increases slightly from 0.05 to 0.2 with the high-temperature exposure time. Generally, the microstructures in the plasma-sprayed coatings and their evolution in a high-temperature environment are the main causes of the varying anisotropic mechanical properties.

  15. Constrained Response Surface Optimisation and Taguchi Methods for Precisely Atomising Spraying Process

    NASA Astrophysics Data System (ADS)

    Luangpaiboon, P.; Suwankham, Y.; Homrossukon, S.

    2010-10-01

    This research presents a development of a design of experiment technique for quality improvement in automotive manufacturing industrial. The quality of interest is the colour shade, one of the key feature and exterior appearance for the vehicles. With low percentage of first time quality, the manufacturer has spent a lot of cost for repaired works as well as the longer production time. To permanently dissolve such problem, the precisely spraying condition should be optimized. Therefore, this work will apply the full factorial design, the multiple regression, the constrained response surface optimization methods or CRSOM, and Taguchi's method to investigate the significant factors and to determine the optimum factor level in order to improve the quality of paint shop. Firstly, 2κ full factorial was employed to study the effect of five factors including the paint flow rate at robot setting, the paint levelling agent, the paint pigment, the additive slow solvent, and non volatile solid at spraying of atomizing spraying machine. The response values of colour shade at 15 and 45 degrees were measured using spectrophotometer. Then the regression models of colour shade at both degrees were developed from the significant factors affecting each response. Consequently, both regression models were placed into the form of linear programming to maximize the colour shade subjected to 3 main factors including the pigment, the additive solvent and the flow rate. Finally, Taguchi's method was applied to determine the proper level of key variable factors to achieve the mean value target of colour shade. The factor of non volatile solid was found to be one more additional factor at this stage. Consequently, the proper level of all factors from both experiment design methods were used to set a confirmation experiment. It was found that the colour shades, both visual at 15 and 45 angel of measurement degrees of spectrophotometer, were nearly closed to the target and the defective at quality gate was also reduced from 0.35 WDPV to 0.10 WDPV. This reveals that the objective of this research is met and this procedure can be used as quality improvement guidance for paint shop of automotive vehicle.

  16. A composition joint PDF method for the modeling of spray flames

    NASA Technical Reports Server (NTRS)

    Raju, M. S.

    1995-01-01

    This viewgraph presentation discusses an extension of the probability density function (PDF) method to the modeling of spray flames to evaluate the limitations and capabilities of this method in the modeling of gas-turbine combustor flows. The comparisons show that the general features of the flowfield are correctly predicted by the present solution procedure. The present solution appears to provide a better representation of the temperature field, particularly, in the reverse-velocity zone. The overpredictions in the centerline velocity could be attributed to the following reasons: (1) the use of k-epsilon turbulence model is known to be less precise in highly swirling flows and (2) the swirl number used here is reported to be estimated rather than measured.

  17. 10 CFR 431.264 - Uniform test method for the measurement of flow rate for commercial prerinse spray valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Uniform test method for the measurement of flow rate for... Valves Test Procedures § 431.264 Uniform test method for the measurement of flow rate for commercial..., the water consumption flow rate of commercial prerinse spray valves. (b) Testing and Calculations....

  18. 10 CFR 431.264 - Uniform test method for the measurement of flow rate for commercial prerinse spray valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Uniform test method for the measurement of flow rate for... Valves Test Procedures § 431.264 Uniform test method for the measurement of flow rate for commercial..., the water consumption flow rate of commercial prerinse spray valves. (b) Testing and Calculations....

  19. Thermal sprayed composite melt containment tubular component and method of making same

    DOEpatents

    Besser, Matthew F. (Urbandale, IA); Terpstra, Robert L. (Ames, IA); Sordelet, Daniel J. (Ames, IA); Anderson, Iver E. (Ames, IA)

    2002-03-19

    A tubular thermal sprayed melt containment component for transient containment of molten metal or alloy wherein the tubular member includes a thermal sprayed inner melt-contacting layer for contacting molten metal or alloy to be processed, a thermal sprayed heat-generating layer deposited on the inner layer, and an optional thermal sprayed outer thermal insulating layer. The thermal sprayed heat-generating layer is inductively heated as a susceptor of an induction field or electrical resistively heated by passing electrical current therethrough. The tubular thermal sprayed melt containment component can comprise an elongated melt pour tube of a gas atomization apparatus where the melt pour tube supplies molten material from a crucible to an underlying melt atomization nozzle.

  20. A microbiologic investigation following the disinfection of irreversible hydrocolloid materials using the spray method.

    PubMed

    Ghahramanloo, Ahmad; Sadeghian, Ali; Sohrabi, Keyvan; Bidi, Ali

    2009-07-01

    Antimicrobial efficacy of three spray disinfectants--0.525 percent sodium hypochlorite (bleach), deconex and Sanosil--was evaluated on contaminated alginate disks. Disks were sprayed eight to 10 times after rinsing in water for 15 seconds. The samples were then placed into plastic bags containing a sterile moist cotton roll for 10 minutes. The use of 0.525 percent sodium hypochlorite sprayed onto the surface of alginate effectively disinfected 96.6 percent of the samples. PMID:19653403

  1. Characterization of cracking within thermal spray deposits by an acoustic emission methodExtended abstract

    NASA Astrophysics Data System (ADS)

    Berndt, C. C.; Lin, C. K.; Leigh, S. H.

    1998-09-01

    Four-point bend tests with in situ acoustic emission (AE) were used to study the cracking behavior of alumina-3% titania materials prepared by gas- and water-stabilized plasma technologies (GSP and WSP, respectively). Catastrophic failure was observed for GSP-sprayed samples while WSP-sprayed samples exhibited microcracking before failure. The amplitude and energy distributions were also investigated, and it was determined that the percentage of macrocracks for GSP-sprayed samples is much larger than for WSP-sprayed samples. The processing effects, which induced differences in microstructure, may account for the differences in AE responses.

  2. Comparative study on combined co-pyrolysis/gasification of walnut shell and bituminous coal by conventional and congruent-mass thermogravimetric analysis (TGA) methods.

    PubMed

    Zhang, Yan; Fan, Di; Zheng, Yan

    2016-01-01

    Combined co-pyrolysis/gasification of bituminous coal (BC) and walnut shell (WS) are comparatively studied with both conventional and congruent-mass thermogravimertric analysis (TGA) methods. The results indicate that BC and WS exhibit additivity in the co-pyrolysis step. However, the gasification reactivity of chars in subsequent gasification step exhibits remarkable sample-mass dependence, which causes the illusions in synergy and inhibition effects when conventional TGA tests are conducted. A congruent-mass TGA method has been developed to overcome the limitations of the conventional TGA mode. One of the advantages of this method is that it can reduce to a minimum the effect of sample mass on reactivity. Thus, the degree of synergy or inhibition can be directly estimated from the deviation of the experimental TG curves between the two separated and blended samples. We recommend this method in studying the co-processing behavior between coal and biomass. PMID:26306847

  3. Characterization of CuZnO Diodes Prepared by Ultrasonic Spray Method

    NASA Astrophysics Data System (ADS)

    Chen, Lung-Chien; Hsieh, Cheng-An

    2015-12-01

    Zinc oxide (ZnO) nanostructures have attracted considerable research interest owing to their useful properties. Recently, doping with Cu atoms has been increasingly attracting attention because of its potential applications in semiconductor devices. In this study, CZO films were prepared on glass substrates by an ultrasonic spray method using zinc acetate, copper acetate, and aqueous ammonium acetate as precursors. The electrical and optical properties of the prepared CZO films and the ZnO/CZO diodes are discussed. This study comprises two parts. First, CZO films with Cu weight percentages from 10 wt.% to 30 wt.%. The electrical and optical properties of the CZO films were measured and compared. Second, a ZnO/CZO diode was fabricated on an ITO substrate. The I- V curve of the device was obtained with or without exposure to a magnetic field.

  4. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water. PMID:26369193

  5. Characterization of CuZnO Diodes Prepared by Ultrasonic Spray Method

    NASA Astrophysics Data System (ADS)

    Chen, Lung-Chien; Hsieh, Cheng-An

    2015-11-01

    Zinc oxide (ZnO) nanostructures have attracted considerable research interest owing to their useful properties. Recently, doping with Cu atoms has been increasingly attracting attention because of its potential applications in semiconductor devices. In this study, CZO films were prepared on glass substrates by an ultrasonic spray method using zinc acetate, copper acetate, and aqueous ammonium acetate as precursors. The electrical and optical properties of the prepared CZO films and the ZnO/CZO diodes are discussed. This study comprises two parts. First, CZO films with Cu weight percentages from 10 wt.% to 30 wt.%. The electrical and optical properties of the CZO films were measured and compared. Second, a ZnO/CZO diode was fabricated on an ITO substrate. The I-V curve of the device was obtained with or without exposure to a magnetic field.

  6. An approximate method for analyzing transient condensation on spray in HYLIFE-II

    SciTech Connect

    Bai, R.Y.; Schrock, V.E. . Dept. of Nuclear Engineering)

    1990-01-01

    The HYLIFE-II conceptual design calls for analysis of highly transient condensation on droplets to achieve a rapidly decaying pressure field. Drops exposed to the required transient vapor pressure field are first heated by condensation but later begin to reevaporate after the vapor temperature falls below the drop surface temperature. An approximate method of analysis has been developed based on the assumption that the thermal resistance is concentrated in the liquid. The time dependent boundary condition is treated via the Duhamel integral for the pure conduction model. The resulting Nusselt number is enhanced to account for convection within the drop and then used to predict the drop mean temperature history. Many histories are considered to determine the spray rate necessary to achieve the required complete condensation.

  7. Method and Apparatus for Thermal Spraying of Metal Coatings Using Pulsejet Resonant Pulsed Combustion

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E. (Inventor)

    2010-01-01

    An apparatus and method [or thermal spraying a metal coating on a substrate is accomplished with a modified pulsejet and optionally an ejector to assist in preventing oxidation. Metal such a Aluminum or Magnesium may be used. A pulsejet is first initiated by applying fuel, air. and a spark. Metal is inserted continuously in a high volume of meta1 into a combustion chamber of the pulsejet. The combustion is thereafter. controlled resonantly at high frequency and the metal is heated to a molten state. The metal is then transported from the combustion chamber into a tail pipe of said pulsejet and is expelled therefrom at high velocity and deposited on a target substrate.

  8. Comparative study of telmisartan tablets prepared via the wet granulation method and pritor™ prepared using the spray-drying method.

    PubMed

    Park, Junsung; Park, Hee Jun; Cho, Wonkyung; Cha, Kwang-Ho; Yeon, Wonki; Kim, Min-Soo; Kim, Jeong-Soo; Hwang, Sung-Joo

    2011-03-01

    The wet granulation method was successfully used to manufacture amorphous telmisartan tablets (CNU) for comparison with the spray-drying method, used for Pritor™. Drug crystallinity in the tablet was characterized using differential scanning calorimetry and powder X-ray diffraction, and pharmaceutical properties of the tablets such as hardness, friability, water absorption, and in vitro dissolution in pH 1.2, 4.0, 6.8 and 7.5 were characterized. Especially with regard to the water absorption feature, the CNU tablets showed better performance by maintaining their original structures and by absorbing less water. Since both Pritor™ and CNU tablets had similar physical properties of crystallinity, hardness, friability, and > 50 f(2) value in an in vitro dissolution study, the bioequivalence of CNU tablets should be analyzed in a future in vivo study. Therefore, telmisartan tablets can be produced using a more economical and easier method than that used to produce Pritor™ tablets. PMID:21547679

  9. Optimization of the HOVF Spray Parameters by Taguchi Method for High Corrosion-Resistant Fe-Based Coatings

    NASA Astrophysics Data System (ADS)

    Qin, Yujiao; Wu, Yuping; Zhang, Jianfeng; Hong, Sheng; Guo, Wenmin; Chen, Liyan; Liu, Hao

    2015-07-01

    Taguchi method was used to optimize the parameters of the high velocity oxygen fuel (HVOF) spray process and obtain the high corrosion-resistant Fe-based coatings. Based on the signal-to-noise ( S/ N) ratio and the analysis of variance, the significance of spray parameters in determining the porosity of the coatings was found to be in the order of spray distance, oxygen flow, and kerosene flow. Thus, the optimal parameters for the porosity of the HVOF sprayed Fe-based coating were determined as 280 mm for the spray distance, 963 scfh for the oxygen flow, and 28 gph for the kerosene flow. The potentiodynamic polarization and EIS tests indicated that the Fe-based coating prepared with the optimal parameters exhibited a higher corrosion potential ( E corr) of -196.14 mV, a lower corrosion current density ( i corr) of 0.14 ?A/cm2, and a higher coating resistance ( R c) of 2.26 106 ? cm2 than those of the hard chromium coating in 3.5% sodium chloride solution. This superior corrosion resistance could be attributed to the dense structure with low porosity and partially amorphous phases of the Fe-based coatings.

  10. Comparison of KCl denuders with the pyrolysis method and calibration using HgBr2 at an in-service AMNET site

    NASA Astrophysics Data System (ADS)

    McClure, C.; Jaffe, D. A.; Edgerton, E.; Jansen, J. J.

    2013-12-01

    During the summer of 2013, we initiated a project to examine the performance of Tekran measurements of Gaseous Oxidized Mercury (GOM) with a pyrolysis method at the North Birmingham SEARCH site. Measurements started in June 2013 and will run until September 2013. This project responds to recent studies that indicate problems with the KCl denuder method for collection of GOM (e.g. Lyman et al., 2010; Gustin et al., 2013; Ambrose et al., 2013). For this project, we compared two GOM measurement systems, one using the KCl denuder method and a second method using high temperature pyrolysis of Hg compounds and detection of the resulting Hg0 vapors. Both instruments were also calibrated using an HgBr2 source to understand the recovery of one possible atmospheric GOM constituent. Both instruments sampled from a common, heated manifold. Past work has shown that in order to fully transmit HgBr2 sample lines must be made from PFA lines and heated to 100 °C. The transmission rate of HgBr2 during this project is approximately 90% over 25 feet of sample tubing at this temperature. Very preliminary results from this study have found that the transmitted HgBr2 is captured with 95% efficiency in carbon-scrubbed ambient air for both the KCl denuder and the pyrolysis method. However, the denuder method appears to be significantly less efficient in the capture of GOM when sampling unaltered ambient air versus the pyrolysis validation of total Hg0. Therefore, calibration of GOM measurements is essential in order to accurately correct for fluctuations in the GOM capture efficiency. We have also found that calibrations for GOM can be done routinely in the field and that these are essential to fully understand the GOM measurements. At present our calibration system is performed manually, but in principle this method could be readily automated.

  11. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Not Available

    1988-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  12. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Boedeker, L.R.

    1990-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  13. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Not Available

    1990-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or No{sub x} may be helpful if an exhaust processing method is available for one of them.

  14. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Not Available

    1989-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  15. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Boedeker, L.R.

    1990-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  16. Investigation of particulate formation during diesel spray combustion

    SciTech Connect

    Boedeker, L.R.

    1990-01-01

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  17. A Method for Mechanical Characterization of Cold Spray Sputter Targets in PV Manufacturing

    NASA Astrophysics Data System (ADS)

    Vlcek, Johannes; Hardikar, Kedar; Juliano, Daniel R.

    2016-01-01

    In this work, the Brazilian disc test technique is applied to mechanical characterization of cold-sprayed Cu-In-Ga deposits. The main advantage of the test is that the material can be tested in its end product form while naturally attending to the distribution of micro-structural phases and flaws by choosing an appropriate specimen size. The stress state of the test specimen can be obtained in analytical closed form and testing can be readily extended to obtain the stress-strain curve. While limited to low ductility materials the Brazilian disc test appears ideal for testing as-sprayed cold spray deposits due to their typically brittle nature.

  18. A Method for Mechanical Characterization of Cold Spray Sputter Targets in PV Manufacturing

    NASA Astrophysics Data System (ADS)

    Vlcek, Johannes; Hardikar, Kedar; Juliano, Daniel R.

    2015-09-01

    In this work, the Brazilian disc test technique is applied to mechanical characterization of cold-sprayed Cu-In-Ga deposits. The main advantage of the test is that the material can be tested in its end product form while naturally attending to the distribution of micro-structural phases and flaws by choosing an appropriate specimen size. The stress state of the test specimen can be obtained in analytical closed form and testing can be readily extended to obtain the stress-strain curve. While limited to low ductility materials the Brazilian disc test appears ideal for testing as-sprayed cold spray deposits due to their typically brittle nature.

  19. Pyrolysis products of PCBs

    SciTech Connect

    Paasivirta, J.; Herzschuh, R.; Humppi, T.; Kantolahti, E.; Knuutinen, J.; Lahtiperae, M.; Laitinen, R.; Salovaara, J.; Tarhanen, J.; Virkki, L.

    1985-05-01

    Model compounds studies which were previously done for impurities and environmental residues of chlorophenols and for wastes of chlorination processes were extended to the impurities and pyrolysis products of polychlorinated biphenyls (PCBs). Model compounds were commercial products or synthesized and their structures proven by spectroscopic methods. These models were used as analytical reference substances in GC/ECD and GC/MS studies of the pyrolyzed PCB samples. In addition to previously known neutral components like polychlorinated dibenzofurans (PCDFs), chlorophenolic substances, especially polychlorophenols (PCPs) and polychlorinated biphenylols (PCB-OHs) were observed as major pyrolysis products of PCBs. Capacitor fires are suggested to produce in many cases chlorophenols which are major toxic hazards to people.

  20. Method for minimizing decarburization and other high temperature oxygen reactions in a plasma sprayed material

    DOEpatents

    Lenling, William J.; Henfling, Joseph A.; Smith, Mark F.

    1993-06-08

    A method is disclosed for spray coating material which employs a plasma gun that has a cathode, an anode, an arc gas inlet, a first powder injection port, and a second powder injection port. A suitable arc gas is introduced through the arc gas inlet, and ionization of the arc gas between the cathode and the anode forms a plasma. The plasma is directed to emenate from an open-ended chamber defined by the boundary of the anode. A coating is deposited upon a base metal part by suspending a binder powder within a carrier gas that is fed into the plasma through the first powder injection port; a material subject to degradation by high temperature oxygen reactions is suspended within a carrier gas that is fed into the plasma through the second injection port. The material fed through the second injection port experiences a cooler portion of the plasma and has a shorter dwell time within the plasma to minimize high temperature oxygen reactions. The material of the first port and the material of the second port intermingle within the plasma to form a uniform coating having constituent percentages related to the powder-feed rates of the materials through the respective ports.

  1. Influence of Particle Velocity of Copper on Emitter Contact by Cold-Spray Method

    NASA Astrophysics Data System (ADS)

    Kang, Byungjun; Lee, Kyung Dong; Lee, Jong-gun; Choi, Jae-Wook; Yoon, Sam S.; Kang, Yoonmook; Lee, Hae-seok; Kim, Donghwan

    2015-12-01

    In this study, we investigated cold-sprayed copper as a front contact for crystalline silicon solar cells. Copper powder was deposited on a monocrystalline silicon wafer with variation of the particle velocity during deposition. The particle velocity was varied by varying the heating temperature from 250 to 400 C using a gas pressure of 0.45 MPa. The particle velocities were calculated using empirical equations, and were found to increase with an increase in the carrier gas temperature. Grid patterns were formed on a phosphorus-doped n-type emitter of a p-type silicon substrate. The electrode thickness increased with increasing particle velocity. The electrical properties of the grids were evaluated using the transfer length method. The specific contact resistance of the n-type emitter was in the range of 2.6-26.4 m?-cm2. Damage to the p-n junction was investigated via minority carrier lifetime measurement of the substrate. The copper-silicon interface was evaluated using transmission electron microscopy. The contact properties were affected by the interface conditions.

  2. Evaluation of phosphorus adsorption capacity of sesame straw biochar on aqueous solution: influence of activation methods and pyrolysis temperatures.

    PubMed

    Park, J H; Ok, Y S; Kim, S H; Cho, J S; Heo, J S; Delaune, R D; Seo, D C

    2015-12-01

    The phosphorus (P) adsorption characteristic of sesame straw biochar prepared with different activation agents and pyrolysis temperatures was evaluated. Between 0.109 and 0.300 mg L(-1) in the form of inorganic phosphate was released from raw sesame straw biochar in the first 1 h. The release of phosphate was significantly enhanced from 62.6 to 168.2 mg g(-1) as the pyrolysis temperature increased. Therefore, sesame straw biochar cannot be used as an adsorbent for P removal without change in the physicochemical characteristics. To increase the P adsorption of biochar in aqueous solution, various activation agents and pyrolysis temperatures were applied. The amount of P adsorbed from aqueous solution by biochar activated using different activation agents appeared in the order ZnCl2 (9.675 mg g(-1)) > MgO (8.669 mg g(-1)) ? 0.1N-HCl > 0.1N-H2SO4 > K2SO4 ? KOH ? 0.1N-H3PO4, showing ZnCl2 to be the optimum activation agent. Higher P was adsorbed by the biochar activated using ZnCl2 under different pyrolysis temperatures in the order 600 C > 500 C > 400 C > 300 C. Finally, the amount of adsorbed P by activated biochar at different ratios of biochar to ZnCl2 appeared in the order 1:3 ? 1:1 > 3:1. As a result, the optimum ratio of biochar to ZnCl2 and pyrolysis temperature were found to be 1:1 and 600 C for P adsorption, respectively. The maximum P adsorption capacity by activated biochar using ZnCl2 (15,460 mg kg(-1)) was higher than that of typical biochar, as determined by the Langmuir adsorption isotherm. Therefore, the ZnCl2 activation of sesame straw biochar was suitable for the preparation of activated biochar for P adsorption. PMID:26040973

  3. Miniature spray-painting booth

    NASA Technical Reports Server (NTRS)

    Fee, K. W.

    1970-01-01

    Transparent spray booth provides method for quality painting and repair of surfaces in clean room or other specialized environments. Overspray and virtually all contaminating vapor and odor can be eliminated. Touch-up painting is achieved with spray gun.

  4. Toxicity of pyrolysis gases from polyoxymethylene

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Schneider, J. E.; Brauer, D. P.

    1979-01-01

    A sample of polyoxymethylene was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. Under several test conditions, this material gave shorter times to death than many other synthetic polymers. Carbon monoxide appeared to be the principal toxicant in the pyrolysis gases.

  5. Toxicity of pyrolysis gases from polyether sulfone

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Olcomendy, E. M.

    1979-01-01

    A sample of polyether sulfone was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. Animal response times were relatively short at pyrolysis temperatures of 600 to 800 C, with death occurring within 6 min. The principal toxicant appeared to be a compound other than carbon monoxide.

  6. Method and closing pores in a thermally sprayed doped lanthanum chromite interconnection layer

    DOEpatents

    Singh, P.; Ruka, R.J.

    1995-02-14

    A dense, substantially gas-tight electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an air electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO{sub 3} particles doped with an element or elements selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by thermal spraying doped LaCrO{sub 3} particles, either by plasma arc spraying or flame spraying; (C) depositing a mixture of CaO and Cr{sub 2}O{sub 3} on the surface of the thermally sprayed layer; and (D) heating the doped LaCrO{sub 3} layer coated with CaO and Cr{sub 2}O{sub 3} surface deposit at from about 1,000 C to 1,200 C to substantially close the pores, at least at a surface, of the thermally sprayed doped LaCrO{sub 3} layer. The result is a dense, substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the nonselected portion of the air electrode. A fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell, for example for generation of electrical power. 5 figs.

  7. Method and closing pores in a thermally sprayed doped lanthanum chromite interconnection layer

    DOEpatents

    Singh, Prabhakar (Export, PA); Ruka, Roswell J. (Pittsburgh, PA)

    1995-01-01

    A dense, substantially gas-tight electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an air electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element or elements selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by thermal spraying doped LaCrO.sub.3 particles, either by plasma arc spraying or flame spraying; (C) depositing a mixture of CaO and Cr.sub.2 O.sub.3 on the surface of the thermally sprayed layer; and (D) heating the doped LaCrO.sub.3 layer coated with CaO and Cr.sub.2 O.sub.3 surface deposit at from about 1000.degree. C. to 1200.degree. C. to substantially close the pores, at least at a surface, of the thermally sprayed doped LaCrO.sub.3 layer. The result is a dense, substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the nonselected portion of the air electrode. A fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell, for example for generation of electrical power.

  8. Production and analysis of fast pyrolysis oils from proteinaceous biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fast pyrolysis of lignocellulosic biomass is a facile method for producing high yields of liquid fuel intermediates. However, because most fast pyrolysis oils are highly oxygenated, acidic and unstable identification of feedstocks that produce higher quality pyrolysis liquids is desirable. Therefor...

  9. Method for Thermal Spraying of Coatings Using Resonant-Pulsed Combustion

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2008-01-01

    A method has been devised for high-volume, high-velocity surface deposition of protective metallic coatings on otherwise vulnerable surfaces. Thermal spraying is used whereby the material to be deposited is heated to the melting point by passing through a flame. Rather than the usual method of deposition from the jet formed from the combustion products, this innovation uses non-steady combustion (i.e. high-frequency, periodic, confined bursts), which generates not only higher temperatures and heat transfer rates, but exceedingly high impingement velocities an order of magnitude higher than conventional thermal systems. Higher impingement rates make for better adhesion. The high heat transfer rates developed here allow the deposition material to be introduced, not as an expensive powder with high surface-area-to-volume, but in convenient rod form, which is also easier and simpler to feed into the system. The nonsteady, resonant combustion process is self-aspirating and requires no external actuation or control and no high-pressure supply of fuel or air. The innovation has been demonstrated using a commercially available resonant combustor shown in the figure. Fuel is naturally aspirated from the tank through the lower Tygon tube and into the pulsejet. Air for starting is ported through the upper Tygon tube line. Once operation commences, this air is no longer needed as additional air is naturally aspirated through the inlet. A spark plug on the device is needed for starting, but the process carries on automatically as the operational device is resonant and reignites itself with each 220-Hz pulse.

  10. An improved whitecap timescale for sea spray aerosol production flux modeling using the discrete whitecap method

    NASA Astrophysics Data System (ADS)

    Callaghan, Adrian H.

    2013-09-01

    The discrete whitecap method (DWM) to model the sea spray aerosol (SSA) production flux explicitly requires a whitecap timescale, which up to now has only considered a whitecap decay timescale, ?decay. A reevaluation of the DWM suggests that the whitecap timescale should account for the total whitecap lifetime (?wcap), which consists of both the formation timescale (?form) and the decay timescale (timescale definitions are given in the text). Here values of ?form for 552 oceanic whitecaps measured at the Martha's Vineyard Coastal Observatory on the east coast of the USA are presented, and added to the corresponding values of ?decay to form 552 whitecap timescales. For the majority of whitecaps, ?form makes up about 20-25% of ?wcap, but this can be as large as 70% depending on the value of ?decay. Furthermore, an area-weighted mean whitecap timescale for use in the DWM (?DWM) is defined that encompasses the variable nature of individual whitecap lifetimes within a given time period, and is calculated to be 5.3 s for this entire data set. This value is combined with previously published whitecap coverage parameterizations and estimates of SSA particle production per whitecap area to form a size-resolved SSA production flux parameterization (dF(r80)/dlog10r80). This parameterization yields integrated sea-salt mass fluxes that are largely within the range of uncertainty of recent measurements over the size range 0.029 m < r80 < 0.580 m. Physical factors controlling whitecap lifetime such as bubble plume lifetime and surfactant stabilization are discussed in the context of SSA production from whitecaps.

  11. Spray momentum measuring system

    NASA Technical Reports Server (NTRS)

    Sheffield, E. W.

    1971-01-01

    Technique enables accurate prediction of erosion and cavitation produced by fluid spray. Method measures high velocity sprays produced by small orifices. Originally designed to determine oxidizer-injection patterns of liquid fueled rocket engines, technique is used with other liquids, or, with appropriate modification, with gases.

  12. Evaluation of the Microcentrifuge Dissolution Method as a Tool for Spray-Dried Dispersion.

    PubMed

    Wu, Benjamin; Li, Jinjiang; Wang, Yahong

    2016-03-01

    Although using spray-dried dispersions (SDDs) to improve the bioavailability of poorly water-soluble compounds has become a common practice in supporting the early phases of clinical studies, their performance evaluation, whether in solid dosage forms or alone, still presents significant challenges. A microcentrifuge dissolution method has been reported to quickly assess the dissolution performance of SDDs. While the microcentrifuge dissolution method has been used in the SDD community, there is still a need to understand the mechanisms about the molecular species present in supernatant after centrifugation, the molecular nature of active pharmaceutical ingredients (APIs), as well as the impact of experimental conditions. In this paper, we aim to assess the effect of API and polymer properties on the dissolution behavior of SDDs along with centrifuging parameters, and for this, two poorly water-soluble compounds (indomethacin and ketoconazole) and two commonly used polymers in the pharmaceutical industry (PVP and HPMC-AS) were chosen to prepare SDDs. A typical microcentrifuge dissolution procedure as reported in the publication (Curatolo et al., Pharm Res 26:1419-1431, 2009) was followed. In addition, after separation of the supernatant from precipitation, some of the samples were filtered through filters of various sizes to investigate the particulate nature (particle size) of the supernatant. Furthermore, the centrifuge speed was varied to study sedimentation of API, SDD, or polymer particles. The results indicated that for the SDDs of four drug-polymer pairs, microcentrifuge dissolution exhibited varied behaviors, depending on the polymer and the drug used. The SDDs of indomethacin with either PVP or HPMC-AS showed a reproducible dissolution with minimum variability even after filtration and subjecting to varied centrifugation speed, suggesting that the supernatant behaved solution-like. However, ketoconazole-PVP and ketoconazole-HPMC-AS SDDs displayed a significant variation in concentration as the speed of centrifugation and the pore sizes of filters were altered, indicating that their supernatant was heterogeneous with the presence of particulates. In conclusion, microcentrifuge dissolution method was more suitable for indomethacin-PVP and indomethacin-HPMC-AS systems compared with ketoconazole-PVP and ketoconazole-HPMC-AS. Therefore, the use of microcentrifuge dissolution method depends on both compounds and polymers selected, which should be examined case by case. PMID:26831250

  13. Method and apparatus for pyrolysis--porous layer open tubular column--cryoadsorption headspace sampling and analysis.

    PubMed

    Bruno, Thomas J; Nichols, Jessica E

    2013-04-19

    In previous work, dynamic headspace vapor collection on short, porous layer open tubular (PLOT) capillary columns maintained at low temperature was introduced. In this paper, that metrology is extended with the introduction of a small in situ pyrolysis platform that provides for rapid heating and rapid vapor capture for a wide variety of samples. The new approach is referred to as pyro-PLOT-cryo. The pyrolysis platform is made from two small copper lead wires that hold a basket formed from small diameter, high resistance stainless steel or NiCr wire. The basket is formed to accept a small sample, the mass of which can typically range from 0.2 to 0.05 mg. The pyrolysis is performed by use of a resistor capacitor circuit of the type used in spot welders. We have provided examples of the application of this technique with the analysis of facial cosmetics, plastic explosives, organometallic gasoline additives, polymers, and in micro scale chemical reactions. Additional modifications and future work are also discussed. PMID:23477797

  14. APPLICATION OF A SPRAY DEPOSITION METHOD FOR REVERSED PHASE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

    EPA Science Inventory

    Four coal gasification wastewater samples were analyzed for nonvolatile and polar organics by liquid chromatography-mass spectrometry (LC/MS). Samples were separated on a reverse phase liquid chromatographic column using an aqueous solvent as the eluant. A special spray depositio...

  15. Kinetic investigation of wood pyrolysis

    SciTech Connect

    Thurner, F.; Mann, U.; Beck, S. R.

    1980-06-01

    The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

  16. Antistatic sprays

    NASA Technical Reports Server (NTRS)

    Ming, James E.

    1989-01-01

    Antistatic sprays from several different manufacturers are examined. The sprays are examined for contamination potential (i.e., outgassing and nonvolatile residue), corrosiveness on an aluminum mirror surface, and electrostatic effectiveness. In addition, the chemical composition of the antistatic sprays is determined by infrared spectrophotometry, mass spectrometry, and ultraviolet spectrophotometry. The results show that 12 of the 17 antistatic sprays examined have a low contamination potential. Of these sprays, 7 are also noncorrosive to an aluminum surface. And of these, only 2 demonstrate good electrostatic properties with respect to reducing voltage accumulation; these sprays did not show a fast voltage dissipation rate however. The results indicate that antistatic sprays can be used on a limited basis where contamination potential, corrosiveness, and electrostatic effectiveness is not critical. Each application is different and proper evaluation of the situation is necessary. Information on some of the properties of some antistatic sprays is presented in this document to aid in the evaluation process.

  17. Preparation and Characterization of Celecoxib Dispersions in Soluplus®: Comparison of Spray Drying and Conventional Methods

    PubMed Central

    Homayouni, Alireza; Sadeghi, Fatemeh; Nokhodchi, Ali; Varshosaz, Jaleh; Afrasiabi Garekani, Hadi

    2015-01-01

    The present study deals with characterization of dispersions of a poorly water-soluble drug, celecoxib (CLX) in polyvinyl caprolactame–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus® (SOL)) prepared by different techniques. Dispersions of CLX in SOL at different ratios (2:1, 1:1, 1:2, 1:4 and 1:6) were prepared by spray drying, conventional solvent evaporation and melting methods. The solid states of samples were characterized using particle size measurements, optical and scanning electron microscopy, XRPD, DSC and FT-IR. The Gordon-Taylor equation was used to predict the Tg of samples and the possibility of interaction between CLX and SOL. The solubility and dissolution rate of all samples were determined. Stability of samples was studied at ambient conditions for a period of 12 months. DSC and XRPD analyses confirmed amorphous state of drug in samples. Surprisingly dispersions of CLX:SOL with the ratio of 2:1 and 1:1 showed slower dissolution rate than CLX while other samples showed higher dissolution rate. At 1:2 ratio the spray dried samples exhibited higher dissolution rate than corresponding samples prepared by other methods. However at higher SOL content (1:4 and 1:6), samples prepared by different methods showed similar dissolution profiles. The stability studies showed that there were no remarkable changes in the dissolution profiles and solid state of the drug after 12 months storage at ambient conditions. It was concluded that SOL was a proper carrier to enhance the dissolution rate of CLX. At high SOL ratios the method of preparation of dispersed samples had no effect on dissolution rate, whilst at low SOL content spray drying was more efficient method. PMID:25561910

  18. Method for thermally spraying crack-free mullite coatings on ceramic-based substrates

    NASA Technical Reports Server (NTRS)

    Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor); Heidorn, Raymond W. (Inventor)

    2000-01-01

    A process for depositing a mullite coating on a silicon-based material, such as those used to form articles exposed to high temperatures and including the hostile thermal environment of a gas turbine engine. The process is generally to thermally spray a mullite powder to form a mullite layer on a substrate, in which the thermal spraying process is performed so that the mullite powder absorbs a sufficient low level of energy from the thermal source to prevent evaporation of silica from the mullite powder. Processing includes deposition parameter adjustments or annealing to maintain or reestablish phase equilibrium in the mullite layer, so that through-thickness cracks in the mullite layer are avoided.

  19. Method for thermally spraying crack-free mullite coatings on ceramic-based substrates

    NASA Technical Reports Server (NTRS)

    Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor); Heidorn, Raymond W. (Inventor)

    2001-01-01

    A process for depositing a mullite coating on a silicon-based material, such as those used to form articles exposed to high temperatures and including the hostile thermal environment of a gas turbine engine. The process is generally to thermally spray a mullite powder to form a mullite layer on a substrate, in which the thermal spraying process is performed so that the mullite powder absorbs a sufficient low level of energy from the thermal source to prevent evaporation of silica from the mullite powder. Processing includes deposition parameter adjustments or annealing to maintain or reestablish phase equilibrium in the mullite layer, so that through-thickness cracks in the mullite layer are avoided.

  20. Method for the determination of lignin content of a sample by flash pyrolysis in an atmosphere of hydrogen or helium and method therefor

    NASA Technical Reports Server (NTRS)

    Shakkottai, Parthasarathy (Inventor); Kwack, Eug Y. (Inventor); Lawson, Daniel D. (Inventor)

    1991-01-01

    The lignin content of wood, paper pulp or other material containing lignin (such as filter paper soaked in black liquor) is more readily determined by flash pyrolysis of the sample at approximately 550.degree. C. in a reducing atmosphere of hydrogen or in an inert atmosphere of helium followed by a rapid analysis of the product gas by a mass spectrometer. The heated pyrolysis unit as fabricated comprises a small platinum cup welded to an electrically-heated stainless steel ribbon with control means for programmed short duration (1.5 sec, approximately) heating and means for continuous flow of hydrogen or helium. The pyrolysis products enter an electron-ionization mode mass spectrometer for spectral evaluation. Lignin content is obtained from certain ratios of integrated ion currents of many mass spectral lines, the ratios being linearly related to the Kappa number of Klason lignin.

  1. Formation of P3KHT:PCBM bulk-heterojunction using orthogonal solvents by ultrasonic spray method

    NASA Astrophysics Data System (ADS)

    Mahajan, Mrunal S.; Lonkar, Ganesh S.; Ghosh, Sanjay S.; Patil, Mahendra B.; Dalal, Dipak S.; Sali, Jaydeep V.

    2015-07-01

    Bulk-heterojunction (BHJ) morphologies with pure domains and sharp interfaces can lead to a more pronounced photovoltaic performance in organic solar cells. In this paper we report the formation of bulk-heterojunction of P3KHT (poly [3-(sodium-6 hexanoate) thiophene-2, 5-diyl]) and PCBM (phenyl-C61-butyric acid methyl ester) using orthogonal solvents by the ultrasonic spray method, which can lead to pure phases and sharp interfaces. P3KHT and PCBM are soluble in water and chlorobenzene respectively, which are orthogonal solvents. The modelling and simulation of the ultrasonic spray method is reported, and shows the possibility of formation of interconnecting phases of the two components in P3KHT:PCBM BHJ, formed using orthogonal solvents, if specific process parameters are chosen. The modelling and simulation also presents a way to determine optimum parameter space in an intermittent spray deposition method using orthogonal solvents. P3KHT:PCBM BHJ has been prepared using three different approaches. Significant photoluminescence quenching, suggesting efficient excitons separation before recombination has been observed in BHJ prepared by the emulsion of solutions method. The study of the optical properties of P3KHT:PCBM BHJ suggests that the BHJ may contain bilayer type structures embedded in the BHJ morphology, which is further confirmed by complementary experiments. This new approach to preparing BHJ with pure phase domains and sharp donor/acceptor interfaces may find applications in optoelectronic devices such as organic thin-film transistors, photodetectors, organic light emitting diodes and organic solar cells.

  2. Non-Destructive Evaluation of Thermal Spray Coating Interface Quality by Eddy Current Method

    SciTech Connect

    B.Mi; X. Zhao; R. Bayles

    2006-05-26

    Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with different surface preparation conditions before applying the coating, e.g., grit-blasted surface, wire-brush cleaned surface, and a dirty surface. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that the three surface preparation conditions can be successfully differentiated by looking into the impedance difference observed from the eddy current probe. The measurement is fairly robust and consistent. More specimens are also prepared with variations of process parameters, such as spray angle, stand-off distance, and application of corrosion protective sealant, etc. They are blindly tested to evaluate the reliability of the eddy current system. Quantitative relations between the coating bond strength and the eddy current response are also established with the support of destructive testing. This non-contact, non-destructive, easy to use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.

  3. An improved method to study the impact of pesticide sprays on small song birds.

    PubMed

    Mineau, P; Sundarem, K M; Sundarem, A; Feng, C; Busby, D G; Pearce, P A

    1990-02-01

    Four test groups of small songbirds (Zebra Finch, Poephila guttata) were sprayed in a chamber with varying concentrations of fenitrothion. Exposure levels were assessed by monitoring air concentrations, deposits of the active ingredient (AI) on glass plates and droplets/cm2 on Kromekote cards. All indices of exposure were linearly correlated and the mean AI deposit on glass plates for the four groups tested with equivalent to 38, 51, 139 and 255 g/ha or 14%, 18%, 50% and 91% of the highest permissible emitted rate for broadscale forest spraying in Canada. Significant depression in body weights and brain acetylcholinesterase levels were noted only for the highest exposure group. Fenitrothion residues in blood were detectable only at the highest exposure level, and in liver at the two higher levels. Carcass and feather residues were much higher than those in blood and liver, and were detectable at all exposure levels but the residues did not increase linearly with exposure. For one of the spray groups, we were able to compute an equivalent acute oral dose based on matching acetylcholinesterase inhibition. PMID:2341701

  4. Optical and electrical characteristics of pyrite films prepared by a new spray method using PVDF as a polymeric binder

    NASA Astrophysics Data System (ADS)

    Javad Zanganeh, Mohammad; Ziarati, Mahmoud; Khandan, Nahid; Goudarzi, Ali Reza

    2015-06-01

    Pyrite thin films were deposited on glass substrates by a new and simple spray method using polyvinylidene fluoride as polymeric binder. Prepared pyrite films were characterized by field emission scanning electron microscopy, ultraviolet-visible spectroscopy and Hall auto-measuring instrument. Hall measurements showed p-type conduction of all the prepared thin films. The film prepared by using binder concentration of 2 wt.% showed the best results. Its band gap was estimated 1.55 eV. Also, electrical characteristics of the deposited film were obtained by I-V characteristic curve.

  5. Kinetics study on conventional and microwave pyrolysis of moso bamboo.

    PubMed

    Dong, Qing; Xiong, Yuanquan

    2014-11-01

    A comparative study on the pyrolysis kinetics of moso bamboo has been conducted in a conventional thermogravimetric analyzer and a microwave thermogravimetric analyzer respectively. The effect of heating rate on the pyrolysis process was also discussed. The results showed that both the maximum and average reaction rates increased with the heating rate increasing. The values of activation energy increased from 58.30 to 84.22 kJ/mol with the heating rate decreasing from 135 to 60 C/min during conventional pyrolysis. The value of activation energy was 24.5 kJ/mol for microwave pyrolysis, much lower than that for conventional pyrolysis at a similar heating rate of 160 C/min. The pyrolysis of moso bamboo exhibited a kinetic compensation effect. The low activation energy obtained under microwave irradiation suggests that microwaves heating would be a promising method for biomass pyrolysis. PMID:25194260

  6. Fundamental Pyrolysis Studies

    SciTech Connect

    Milne, T. A.; Evans, R. J.; Soltys, M. N.

    1983-03-01

    Progress on the direct mass spectrometric sampling of pyrolysis products from wood and its constituents is described for the period from June 1982 to February 1983. A brief summary and references to detailed reports, of the qualitative demonstration of our approach to the study of the separated processes of primary and secondary pyrolysis is presented. Improvements and additions to the pyrolysis and data acquisition systems are discussed and typical results shown. Chief of these are a heated-grid pyrolysis system for controlled primary pyrolysis and a sheathed flame arrangement for secondary cracking studies. Qualitative results of the secondary cracking of cellulose, lignin, and wood are shown as are comparisons with the literature for the pyrolysis spectra of cellulose, lignin, and levoglucosan. 'Fingerprints' for a number of materials are shown, with spectra taken under carefully controlled conditions so that sensitivity calibrations for different compounds, now being determined, can be applied.

  7. A coupled implicit solution method for turbulent spray combustion in propulsion systems

    NASA Astrophysics Data System (ADS)

    Chen, K.-H.; Shuen, J.-S.

    Many reacting flows in propulsion devices cannot be efficiently calculated by modern compressible flow CFD algorithms. Most low-speed reacting flow codes based on TEACH-type technologies are inefficient and lack robustness for complex flows. Tremendous progress has been made in high-speed compressible flow CFD in the past two decades; extending its application range to low-speed regimes is highly desirable. The objectives of this document is to present an efficient and robust algorithm for multi-phase chemically reacting flows at all speeds, with emphasis on low Mach number flows, and to calculate turbulent spray combustion flow in a gas turbine combustor.

  8. Carbon nanoscrolls by pyrolysis of a polymer

    NASA Astrophysics Data System (ADS)

    Yadav, Prasad; Warule, Sambhaji; Jog, Jyoti; Ogale, Satishchandra

    2012-12-01

    3D network of carbon nanoscrolls was synthesized starting from pyrolysis of poly(acrylic acid-co-maleic acid) sodium salt. It is a catalyst-free process where pyrolysis of polymer leads to formation of carbon form and sodium carbonate. Upon water soaking of pyrolysis product, the carbon form undergoes self-assembly to form carbon nanoscrolls. The interlayer distance between the walls of carbon nanoscroll was found to be 0.34 nm and the carbon nanoscrolls exhibited a surface area of 188 m2/g as measured by the BET method.

  9. Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Spengler, C.J.; Folser, G.R.; Vora, S.D.; Kuo, L.; Richards, V.L.

    1995-06-20

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO{sub 3} particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO{sub 3} powder, preferably compensated with chromium as Cr{sub 2}O{sub 3} and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO{sub 3} layer to about 1100 C to 1300 C to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 6 figs.

  10. Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Spengler, Charles J. (Murrysville, PA); Folser, George R. (Lower Burrell, PA); Vora, Shailesh D. (Monroeville, PA); Kuo, Lewis (Monroeville, PA); Richards, Von L. (Anyola, IN)

    1995-01-01

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100.degree. C. to 1300.degree. C. to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell.

  11. Oxymetazoline Nasal Spray

    MedlinePLUS

    Afrin Nasal Spray ... Anefrin Nasal Spray ... Dristan Nasal Spray ... Mucinex Nasal Spray ... Nostrilla Nasal Spray ... Vicks Sinex Nasal Spray ... Zicam Nasal Spray ... Oxymetazoline nasal spray is used to relieve nasal discomfort caused by colds, allergies, and hay fever. It is also ...

  12. Thermal Arc Spray Overview

    NASA Astrophysics Data System (ADS)

    Hafiz Abd Malek, Muhamad; Hayati Saad, Nor; Kiyai Abas, Sunhaji; Mohd Shah, Noriyati

    2013-06-01

    Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

  13. Spray atomization of bio-oil/ethanol blends with externally mixed nozzles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to investigate the properties of sprays of pyrolysis oil from biomass (bio-oil) using an air assisted atomization nozzle operated without combustion to explore the potential of pyrolysis oil combustion in industrial and home furnaces. Bio-oil was blended with ethanol to im...

  14. Delivery of Highly Active Noble-Metal Nanoparticles into Microspherical Supports by an Aerosol-Spray Method.

    PubMed

    Kan, Erjie; Kuai, Long; Wang, Wenhai; Geng, Baoyou

    2015-09-14

    Noble metal nanoparticles (NPs) with 1-5?nm diameter obtained from NaHB4 reduction possess high catalytic activity. However, they are rarely used directly. This work presents a facile, versatile, and efficient aerosol-spray approach to deliver noble-metal NPs into metal oxide supports, while maintaining the size of the NPs and the ability to easily adjust the loading amount. In comparison with the conventional spray approach, the size of the loaded noble-metal nanoparticles can be significantly decreased. An investigation of the 4-nitrophenol hydrogenation reaction catalyzed by these materials suggests that the NPs/oxides catalysts have high activity and good endurance. For 1?%?Au/CeO2 and Pd/Al2 O3 catalysts, the rate constants reach 2.03 and 1.46?min(-1) , which is much higher than many other reports with the same noble-metal loading scale. Besides, the thermal stability of catalysts can be significantly enhanced by modifying the supports. Therefore, this work contributes an efficient method as well as some guidance on how to produce highly active and stable supported noble-metal catalysts. PMID:26234910

  15. Zone heating for fluidized bed silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K. (Inventor)

    1987-01-01

    An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower reaction zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

  16. Catalytic pyrolysis of wheat bran for hydrocarbons production in the presence of zeolites and noble-metals by using TGA-FTIR method.

    PubMed

    Lazdovica, K; Liepina, L; Kampars, V

    2016-05-01

    Pyrolysis of wheat bran with or without catalysts was investigated using TGA-FTIR method in order to determine the influence of zeolite and noble metal catalysts on the evolution profile and relative yield of the volatile compounds. The addition of all catalysts decreased the volatile matter of wheat bran from 76.3% to 75.9%, 73.9%, 73.5%, 69.7% and increased the solid residue from 18.0% to 18.4%, 20.4%, 20.8%, 24.6% under the catalyst of ZSM-5, 5% Pd/C, MCM-41, and 5% Pt/C. Noble-metal catalysts had higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than zeolites. Degradation of nitrogen containing compounds atom proceeded better in presence of zeolites. Noble-metal catalysts promoted formation of aromatics and changed the profiles of evolved compounds whereas zeolites advanced formation of aliphatics and olefins. PMID:26874441

  17. Potential method for gas production: high temperature co-pyrolysis of lignite and sewage sludge with vacuum reactor and long contact time.

    PubMed

    Yang, Xiao; Yuan, Chengyong; Xu, Jiao; Zhang, Weijiang

    2015-03-01

    Lignite and sewage sludge were co-pyrolyzed in a vacuum reactor with high temperature (900C) and long contact time (more than 2h). Beneficial synergetic effect on gas yield was clearly observed. Gas yield of blend fuel was evidently higher than that of both parent fuels. The gas volume yield, gas lower heating value (LHV), fixed carbon conversion and H2/CO ratio were 1.42 Nm(3)/kg(blend fuel), 10.57 MJ/Nm(3), 96.64% and 0.88% respectively, which indicated this new method a feasible one for gas production. It was possible that sewage sludge acted as gasification agents (CO2 and H2O) and catalyst (alkali and alkaline earth metals) provider during co-pyrolysis, promoting CO2-char and H2O-char gasification which, as a result, invited the improvement of gas volume yield, gas lower heating value and fixed carbon conversion. PMID:25542402

  18. Fabrication of multifunctional cellulose nanocrystals/poly(lactic acid) nanocomposites with silver nanoparticles by spraying method.

    PubMed

    Yu, Hou-Yong; Yang, Xing-Yuan; Lu, Fang-Fang; Chen, Guo-Yin; Yao, Ju-Ming

    2016-04-20

    The poly (lactic acid) (PLA)/functionalized cellulose nanocrystals formates (CNFs) were prepared by solution casting and then the binary films were sprayed with silver ammonia aqueous solution to fabricate PLA/CNF/Ag ternary nanocomposites. It was found that both deposited silver (Ag) nanoparticles and CNFs showed efficient reinforcing effect on the thermal, mechanical, barrier properties and antibacterial activity of PLA matrix. Especially, the maximum decomposition temperature (Tmax) and Young's modulus of PLA/CNF/Ag(6) nanocomposite film increased by 15.5°C and 48.7%, respectively. Meanwhile an obvious reduction in the water vapor permeability was detected. Furthermore, the migration levels of the ternary nanocomposite films were well below the permitted limits in both non-polar and polar food simulants (60mgkg(-1)), and they showed a significant antibacterial activity influenced by the Ag contents. This study reveals that the novel nanocomposite films will offer a good perspective for food packaging applications. PMID:26876846

  19. Application of ultrasound to microencapsulation of coconut milk fat by spray drying method.

    PubMed

    Le, Hoang Du; Le, Van Viet Man

    2015-04-01

    Mixtures of coconut milk and gelatin solution were treated by ultrasound, mixed with maltodextrin and subsequently spray-dried to yield powder. The effects of ultrasonic power and sonication time on the microencapsulation efficiency (ME) and microencapsulation yield (MY) of coconut fat were investigated. The results indicated that increase in ultrasonic power from 0 to 5.68W/g and in sonication time from 0 to 2.5min augmented ME and MY of coconut fat. However, treatment with sonication power higher than 5.68W/g led to a drop in fat ME and MY, mainly due to aggregation of fat particles and that blocked the adsorption of gelatin molecules on the particle surface. PMID:25829636

  20. High drug load, stable, manufacturable and bioavailable fenofibrate formulations in mesoporous silica: a comparison of spray drying versus solvent impregnation methods.

    PubMed

    Hong, Shiqi; Shen, Shoucang; Tan, David Cheng Thiam; Ng, Wai Kiong; Liu, Xueming; Chia, Leonard S O; Irwan, Anastasia W; Tan, Reginald; Nowak, Steven A; Marsh, Kennan; Gokhale, Rajeev

    2016-01-01

    Encapsulation of drugs in mesoporous silica using co-spray drying process has been recently explored as potential industrial method. However, the impact of spray drying on manufacturability, physiochemical stability and bioavailability in relation to conventional drug load processes are yet to be fully investigated. Using a 2(3) factorial design, this study aims to investigate the effect of drug-loading process (co-spray drying and solvent impregnation), mesoporous silica pore size (SBA-15, 6.5 nm and MCM-41, 2.5 nm) and percentage drug load (30% w/w and 50% w/w) on material properties, crystallinity, physicochemical stability, release profiles and bioavailability of fenofibrate (FEN) loaded into mesoporous silica. From the scanning electronic microscopy (SEM) images, powder X-ray diffraction and Differential scanning calorimetry measurements, it is indicated that the co-spray drying process was able to load up to 50% (w/w) FEN in amorphous form onto the mesoporous silica as compared to the 30% (w/w) for solvent impregnation. The in vitro dissolution rate of the co-spray dried formulations was also significantly (p?=?0.044) better than solvent impregnated formulations at the same drug loading. Six-month accelerated stability test at 40?C/75% RH in open dish indicated excellent physical and chemical stability of formulations prepared by both methods. The amorphous state of FEN and the enhanced dissolution profiles were well preserved, and very low levels of degradation were detected after storage. The dog data for the three selected co-spray-dried formulations revealed multiple fold increment in FEN bioavailability compared to the reference crystalline FEN. These results validate the viability of co-spray-dried mesoporous silica formulations with high amorphous drug load as potential drug delivery systems for poorly water soluble drugs. PMID:24853963

  1. Pyrolysis system evaluation study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An evaluation of two different pyrolysis concepts which recover energy from solid waste was conducted in order to determine the merits of each concept for integration into a Integrated Utility System (IUS). The two concepts evaluated were a Lead Bath Furnace Pyrolysis System and a Slagging Vertical Shaft, Partial Air Oxidation Pyrolysis System. Both concepts will produce a fuel gas from the IUS waste and sewage sludge which can be used to offset primary fuel consumption in addition to the sanitary disposal of the waste. The study evaluated the thermal integration of each concept as well as the economic impact on the IUS resulting from integrating each pyrolysis concepts. For reference, the pyrolysis concepts were also compared to incineration which was considered the baseline IUS solid waste disposal system.

  2. Supersonic-Spray Cleaner

    NASA Technical Reports Server (NTRS)

    Caimi, Raoul E. B.; Lin, Feng-Nan; Thaxton, Eric A.

    1995-01-01

    Spraying system for cleaning mechanical components uses less liquid and operates at pressures significantly lower. Liquid currently used is water. Designed to replace chlorofluorocarbon (CFC) solvent-based cleaning and cleanliness verification methods. Consists of spray head containing supersonic converging/diverging nozzles, source of gas at regulated pressure, pressurized liquid tank, and various hoses, fittings, valves, and gauges. Parameters of nozzles set so any of large variety of liquids and gases combined in desired ratio and rate of flow. Size and number of nozzles varied so system built in configurations ranging from small hand-held spray heads to large multinozzle cleaners. Also used to verify part adequately cleaned. Runoff liquid from spray directed at part collected. Liquid analyzed for presence of contaminants, and part recleaned if necessary.

  3. Method of making supercritical fluid molecular spray films, powder and fibers

    DOEpatents

    Smith, Richard D.

    1988-01-01

    Solid films are deposited, or fine powders formed, by dissolving a solid material into a supercritical fluid solution at an elevated pressure and then rapidly expanding the solution through a heated nozzle having a short orifice into a region of relatively low pressure. This produces a molecular spray which is directed against a substrate to deposit a solid thin film thereon, or discharged into a collection chamber to collect a fine powder. In another embodiment, the temperature of the solution and nozzle is elevated above the melting point of the solute, which is preferably a polymer, and the solution is maintained at a pressure such that, during expansion, the solute precipitates out of solution within the nozzle in a liquid state. Alternatively, a secondary solvent mutually soluble with the solute and primary solvent and having a higher critical temperature than that of primary solvent is used in a low concentration (<20%) to maintain the solute in a transient liquid state. The solute is discharged in the form of long, thin fibers. The fibers are collected at sufficient distance from the orifice to allow them to solidify in the low pressure/temperature region.

  4. Small-scale hydrous pyrolysis of macromolecular material in meteorites

    NASA Astrophysics Data System (ADS)

    Sephton, M. A.; Pillinger, C. T.; Gilmour, I.

    1998-12-01

    The hydrous pyrolysis method, usually performed on several hundred grams of terrestrial rock sample, has been scaled down to accommodate less than two grams of meteorite sample. This technique makes full use of the high yields associated with hydrous pyrolysis experiments and permits the investigation of the meteorite macromolecular material, the major organic component in carbonaceous meteorites. The hydrous pyrolysis procedure transforms the high molecular weight macromolecular material into low molecular weight fragments. The released entities can then be extracted with supercritical fluid extraction. In contrast to the parent structure, the pyrolysis products are amenable for analysis by gas chromatography-based techniques. When subjected to hydrous pyrolysis, two carbonaceous chondrites (Orgueil and Cold Bokkeveld) released generally similar products, which consisted of abundant volatile aromatic and alkyl-substituted aromatic compounds. These results revealed the ability of small-scale hydrous pyrolysis to dissect extraterrestrial macromolecular material and thereby reveal its organic constitution.

  5. Triboelectric spray ionization.

    PubMed

    Özdemir, Abdil; Lin, Jung-Lee; Gillig, Kent J; Chen, Chung-Hsuan

    2013-02-01

    Triboelectric spray ionization (TESI) is a variation of electrospray ionization (ESI) using common instrumental components, including gas flow, solvent flow rate and heat, the only difference being the use of a high-voltage power supply for ESI or a static charge for TESI. The ionization of solvent or analyte is due to the electrostatic potential difference formed between the spray electrode and counter electrode. The ion source contains a pneumatic spray operated over a range of flow rates (0.15-1.5 µl/min) and gas pressures (0-100). This new design contains a standalone spray assembly and an optional metal mesh in front of the spray. There are several parameters that affect the performance during ionization of molecules including the flow rate of solvent, gas pressure, temperature, solvent acidity, distance and potential difference between emitter and counter electrode. A variable electrostatic potential can be applied for higher ionization efficiency. The new ionization method was successfully applied to solutions of various proteins under different conditions. The same charge-state distributions compared to other ESI techniques are observed for all the protein samples. The unique feature of TESI is very efficient spraying by using a natural electrostatic potential even at the potential that a human body can produce. This provides very gentle ionization efficiency of peptides and proteins in different solvents. PMID:23378087

  6. Nitroglycerin Spray

    MedlinePLUS

    ... container of nitroglycerin spray. This product may catch fire, so do not use near an open flame, ... as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this ...

  7. Catalytic pyrolysis-GC/MS of lignin from several sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin from four different sources extracted by various methods were pyrolyzed at 650 degree C using analytical pyrolysis methods, py-GC/MS. Pyrolysis was carried out in the absence and presence of two heterogeneous catalysts , an acidic zeolite (HZSM-5) catalyst and a mixed metal oxide catalyst (Co...

  8. Vacuum Plasma Spraying Replaces Electrodeposition

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Power, Chris; Burns, David H.; Daniel, Ron; Mckechnie, Timothy N.

    1992-01-01

    Vacuum plasma spraying used to fabricate large parts with complicated contours and inner structures, without uninspectable welds. Reduces time, and expense of fabrication. Wall of combustion chamber built up inside of outer nickel-alloy jacket by plasma spraying. Particles of metal sprayed partially melted in plasma gun and thrown at supersonic speed toward deposition surface. Vacuum plasma-spray produces stronger bond between the grooves and covering layer completing channels and wall of combustion chamber. In tests, bond withstood pressure of 20 kpsi, three times allowable limit by old method.

  9. Plasma pyrolysis of toxic waste

    NASA Astrophysics Data System (ADS)

    Rutberg, Ph G.

    2003-06-01

    The comparison of technical economic indexes of different waste treatment methods and plasma pyrolysis is presented in the paper. It testifies that plasma technologies are economically expedient for these purposes. Physical prerequisites allowing realizing plasma technologies are presented. Reliable and economical (70-120 Euro per ton of treated product) plasma generation is the basic condition of the technology realization. In this connection, various types of powerful generators of dense plasma (plasmatrons) in the range from 100 kW to 3 MW and temperature of plasma jets from 2000 to 10 000 K, and also physical processes taking place in electric-discharge chambers are examined. Differences between AC and DC electric arc plasma generators are analysed. Temperature in arcs of plasma generators varies from 6000 to 20 000 K, electron concentration is ne~(1014-1019 cm-3). Specific ware of electrodes in various types of plasma generators intended for long-time operation modes is (10-7-10-4) g C-1. Physicochemical processes in plasma reactors intended for waste treatment and pyrolysis are described. Different types of technological processes on plasma treatment and pyrolysis of waste are analysed. Estimation of present situation of physical investigations and technological developments in this area and predictions for nearest future are included. This article was scheduled to appear in issue 5 of Plasma Phys. Control. Fusion. To access this Special issue please follow this link: http://www.iop.org/EJ/toc/0741-3335/45/5

  10. Simulations of Spray Reacting Flows in a Single Element LDI Injector With and Without Invoking an Eulerian Scalar PDF Method

    NASA Technical Reports Server (NTRS)

    Shih, Tsan-Hsing; Liu, Nan-Suey

    2012-01-01

    This paper presents the numerical simulations of the Jet-A spray reacting flow in a single element lean direct injection (LDI) injector by using the National Combustion Code (NCC) with and without invoking the Eulerian scalar probability density function (PDF) method. The flow field is calculated by using the Reynolds averaged Navier-Stokes equations (RANS and URANS) with nonlinear turbulence models, and when the scalar PDF method is invoked, the energy and compositions or species mass fractions are calculated by solving the equation of an ensemble averaged density-weighted fine-grained probability density function that is referred to here as the averaged probability density function (APDF). A nonlinear model for closing the convection term of the scalar APDF equation is used in the presented simulations and will be briefly described. Detailed comparisons between the results and available experimental data are carried out. Some positive findings of invoking the Eulerian scalar PDF method in both improving the simulation quality and reducing the computing cost are observed.

  11. Spray combustion of synthetic fuels. Phase II. Spray-combustion phenomena. Final report, 9 September 1981-31 December 1982

    SciTech Connect

    Not Available

    1983-05-01

    The objectives of this project were to augment existing information on physical and chemical processes relevant to synfuel combustion, to develop fundamental information and data bases applicable to synfuel utilization in industrial combustors, and to develop associated combustion models and synfuel utilization criteria with special emphasis on spray combustion. An integrated analytical and experimental program has been constructed to provide an understanding of the phenomena involved in the combustion of synthetic fuels: An extensive literature search was conducted to collect and collate available data on the thermodynamics and kinetics of pyrolysis and oxidation of synthetic fuels, related compounds, and baseline, petroleum-derived fuels. Bench-scale spray dynamics experiments were conducted to obtain data on spray combustion processes. Modular models of the combined aerodynamic and chemical processes of spray combustion were developed to represent basic spray combustor configurations. Chemical kinetics formulations were developed to model pyrolysis, soot formation and oxidation, aliphatic and aromatic hydrocarbon oxidation, and fuel-bound nitrogen conversion. These chemical kinetics formulations were based on the quasiglobal approach and were to be suitable for use in the modular spray combustion model. Models of the overall spray combustion process were used in the design of the experimental facility. The analytical models were refined and tested using the results of experiments conducted in the bench-scale spray dynamics test facility and data from other sources. The results of the modeling and experimental program were used to develop fundamental information relevant to the effective utilization of synfuels in industrial combustion systems.

  12. Relationship between hydrous and ordinary pyrolysis

    SciTech Connect

    Burnham, A.K.

    1993-06-01

    Pyrolysis results are reviewed briefly with the intent of drawing comparisons between open, high pressure, and hydrous pyrolysis. Empirically, the degree of pyrolysis severity to form volatile products in open pyrolysis is similar to that required to form an expelled oil phase in hydrous pyrolysis. The yields of hydrocarbons from open pyrolysis are close to those from hydrous pyrolysis, but hydrous pyrolysis tends to assist the separation of hydrocarbons from polar materials. Pressure has a small but measurable affect on the generation kinetics.

  13. Stabilization of Fast Pyrolysis Oil: Post Processing Final Report

    SciTech Connect

    Elliott, Douglas C.; Lee, Suh-Jane; Hart, Todd R.

    2012-03-01

    UOP LLC, a Honeywell Company, assembled a comprehensive team for a two-year project to demonstrate innovative methods for the stabilization of pyrolysis oil in accordance with DOE Funding Opportunity Announcement (FOA) DE-PS36-08GO98018, Biomass Fast Pyrolysis Oil (Bio-oil) Stabilization. In collaboration with NREL, PNNL, the USDA Agricultural Research Service (ARS), Pall Fuels and Chemicals, and Ensyn Corporation, UOP developed solutions to the key technical challenges outlined in the FOA. The UOP team proposed a multi-track technical approach for pyrolysis oil stabilization. Conceptually, methods for pyrolysis oil stabilization can be employed during one or both of two stages: (1) during the pyrolysis process (In Process); or (2) after condensation of the resulting vapor (Post-Process). Stabilization methods fall into two distinct classes: those that modify the chemical composition of the pyrolysis oil, making it less reactive; and those that remove destabilizing components from the pyrolysis oil. During the project, the team investigated methods from both classes that were suitable for application in each stage of the pyrolysis process. The post processing stabilization effort performed at PNNL is described in this report. The effort reported here was performed under a CRADA between PNNL and UOP, which was effective on March 13, 2009, for 2 years and was subsequently modified March 8, 2011, to extend the term to December 31, 2011.

  14. Investigation of particulate formation during diesel spray combustion. Technical progress quarterly report, March 1, 1990--May 31, 1990

    SciTech Connect

    Boedeker, L.R.

    1990-12-31

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  15. Investigation of particulate formation during diesel spray combustion. Technical progress quarterly report, March 1, 1989--May 31, 1989

    SciTech Connect

    Not Available

    1989-12-31

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  16. Investigation of particulate formation during diesel spray combustion. Technical progress quarterly report, December 1, 1988--February 28, 1989

    SciTech Connect

    Not Available

    1989-12-31

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  17. Investigation of particulate formation during diesel spray combustion. Technical progress quarterly report, June 1, 1990--August 31, 1990

    SciTech Connect

    Boedeker, L.R.

    1990-12-31

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  18. Investigation of particulate formation during diesel spray combustion. Technical progress quarterly report, September 1, 1989--November 30, 1989

    SciTech Connect

    Boedeker, L.R.

    1989-12-31

    The objective of the contract is to conduct an experimental and analytical research program to investigate strategies for using coherent anti-Stokes Raman scattering (CARS) laser diagnostic techniques for detecting the degree of fuel pyrolysis and determining fuel-air ratio. Smoke and NO{sub x} production rates depend in a complex way on the local temperature, the evaporation of the diesel spray, the local fuel-air ratio, and the pyrolysis history of the fuel. Furthering the ability of CARS to provide more of this information may give engine designers more insight into the combustion process and allow them to create engines which produce fewer particulates or lower amounts of NO{sub x}. Controlling the production rates is preferable to processing emissions. If they cannot both be suppressed simultaneously, adjusting the tradeoff between producing particulates or NO{sub x} may be helpful if an exhaust processing method is available for one of them.

  19. Identification and characterization of vinylpyrrolidone-vinylimidazolium chloride copolymers in cosmetic products by pyrolysis-gas chromatography-mass spectrometry method.

    PubMed

    Gmahl, E; Ruess, W

    1993-04-01

    Synopsis Commercially available copolymers of 1-vinyl-2-pyrrolidone and 1-vinyl-3-methylimidazolium chloride, known as 'Luviquat' types in the cosmetic industry, were analysed for their composition using a combination of pyrolysis-gas chromatography-mass spectrometry method. This is a report on the determined pyrolytic products and the fast identification of the analysed polymers both in raw materials and cosmetic products. Calibration with defined material ensures the determination of monomer ratios with good reproducibility. Rsum Les copolymres de chlorure de 1-vinyle-2-pyrolidone et de 1-vinyle-3-methylimidazolium disponibles dans le commerce, connus dans l'industrie cosmtique sous la dnomination de copolymres de vinyle, ont t analyss laide d'une mthode combinant la pyrolyse, la spectromtrie de mass et la chromatographie en phase gazeuse. Cet article constitue un rapport sur les produits dtermins par pyrolyse et sur la rapidit d'identification des polymres analyss la fois dans des matires premires et dans des produits cosmtiques. Le calibrage avec un matriel dfini assure une bonne dtermination des taux de monomres dots d'une reproductibilit. PMID:19272122

  20. A new method for transmission of infrared radiation in polydisperse water sprays

    NASA Astrophysics Data System (ADS)

    Du, Yongcheng; Liu, Huikai; Yang, Li

    2015-10-01

    A numerical method is proposed for the transport of infrared radiation in participating medium. The method is implemented using the Finite Volume Method (FVM) for solving the radiative transfer equation (RTE), and Mie theory for computing the absorption and scattering characteristics of the medium. The advantages of the method reflected in two aspects. On the one hand, the radiative characteristics is got from a data base established in advance using Mie theory, on the other hand, the scattering phase function is simplified by distinguishing the "forward average scattering" and "other directional average scattering". Both the two procedures yield significant computational savings with little loss in accuracy for predictions of spectral and total transmission.

  1. Thermal spray processing

    NASA Technical Reports Server (NTRS)

    Herman, H.; Berndt, C. C.

    1995-01-01

    Thermal spray processing has been used for a number of years to cost-effecticely apply TBC's for a wide range of heat engine applications. In particular, bond coats are applied by plasma spray and HVOF techniques and partially-stabilized zirconia top coats are applied by plasma spray methods. Thermal spray involves melting and rapid transport of the molten particles to the substrate, where high-rate solidification and coating build-up occur. It is the very nature of this melt processing that leads to the unique layered microstructure, as well as the apparent imperfections, so readily identified with thermal spray. Modeling the process, process-induced residual stresses, and thermal conductivity will be discussed in light of a new understanding of porosity and its anisotropy. Microcracking can be understood using new approaches, allowing a fuller view of the processing-performance connection. Detailed electron microscopic, novel neutron diffraction and fracture analysis of the deposits can lead to a better understanding of how overall microstructure can be controlled to influence critical properties of the deposited TBC system.

  2. Effect of Sprayed Solution Volume on Physical Properties of Titanium Dioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Naffouti, Wafa; Ben Nasr, Tarek; Briot, Olivier; Kamoun-Turki, Najoua

    2015-10-01

    Titanium dioxide (TiO2) thin films were deposited on glass substrates by spray pyrolysis technique from different solution volumes. We studied the effect of sprayed solution volume on the structural, morphological and optical properties of TiO2 films. X-ray diffraction studies revealed the presence of an anatase phase with a tetragonal structure with (101) preferred orientation. The best crystallinity was obtained in the case of a sprayed solution volume of 60 ml. Also, this film had a lower average surface roughness (RMS) as measured by atomic force microscopy. Transmission and reflection optical analysis showed interference phenomena indicating a smooth reflecting surface of the film. An indirect band gap of about 3.46 eV was found, indicating a potential use of these films in solar cell devices. Based on the optical measurements, the film thickness was determined by the envelope method, which was in agreement with the scanning electron microscopy result. Wemple-Di Domenico single oscillator and Spitzer-Fan models were used to study the optical constants of the films grown from different sprayed solution volumes. Photoluminescence emission intensity was found to increase with increasing film crystallinity, and the spectra showed ultraviolet and visible emissions corresponding to intrinsic emission and trap levels within the band gap, respectively.

  3. Development of method to characterize emissions from spray polyurethane foam insulation

    EPA Science Inventory

    This presentation updates symposium participants re EPA progress towards development of SPF insulation emissions characterization methods. The presentation highlights evaluation of experiments investigating emissions after application of SPF to substrates in micro chambers and i...

  4. The synthesis and optical property of solid-state-prepared YAG:Ce phosphor by a spray-drying method

    SciTech Connect

    Lee, H.-M.; Cheng, C.-C.; Huang, C.-Y.

    2009-05-06

    Ce{sup 3+}-activated yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}:Ce, YAG:Ce) powder as luminescent phosphor was synthesized by the solid-state reaction method. The phase identification, microstructure and photoluminescent properties of the products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), absorption spectrum and photoluminescence (PL) analysis. Spherical phosphor particle is considered better than irregular-shaped particle to improve PL property and application, so this phosphor was granulated into a sphere-like shape by a spray-drying device. After calcinating at 1500 deg. C for 0, 4, and 8 h, the product was identified as YAG and CeO{sub 2} phases. The CeO{sub 2} phase content is decreased by increasing the calcination time or decreasing the Ce{sup 3+} doping content. The product showed higher emission intensity resulted from more Ce{sup 3+} content and larger grain size. The product with CeO{sub 2} was found to have lower emission intensity. This paper presents the crystal structures of Rietveld refinement results of powder XRD data.

  5. Spray plasma device, a new method to process nanostructured layers. application to deposit ZnO thin layers.

    PubMed

    Nikravech, Mehrdad

    2010-02-01

    The aim of this paper is to present a new plasma spray device to deposit nanostructured films. In this process, aqueous droplets of a starting material, in this case, a nitrate salt, of small and uniform size produced in an aerosol generator are injected into a low pressure plasma reactor. Droplets are then submitted to the reactivity of plasma and projected against a substrate where they form the final film. The reactor is designed to reduce the turbulence that results in coalescence of the particles and affects the uniformity of the deposited films. The plasma is produced by an inductive RF generator that avoids the contamination of the layers by electrodes. The control of plasma gas composition, i.e., argon and oxygen, permits adjustment of the concentration of reactive species leading to control the stoichiometry of the deposited layers. The ability of this process to produce nano scale zinc oxide films by the use of an aqueous solution containing Zn(NO3)2 is demonstrated. The films obtained under defined experimental conditions are smooth, colorless and transparent. SEM and AFM photographs show the formation of uniform layers with 20 to 60 nm in thickness. XRD patterns of deposited films showed that preferential c-axis orientation of crystallites depends highly on the concentration of Zn(NO3)2 in the starting solution. Willamson-Hall method in accordance with AFM photographs showed that the size of crystallites ranges between 24 and 34 nm. PMID:20352774

  6. Substrate system for spray forming

    DOEpatents

    Chu, Men G. (Export, PA); Chernicoff, William P. (Harrisburg, PA)

    2000-01-01

    A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

  7. Substrate system for spray forming

    DOEpatents

    Chu, Men G. (Export, PA); Chernicoff, William P. (Harrisburg, PA)

    2002-01-01

    A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

  8. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, C.E.; Seals, R.D.; Price, R.E.

    1997-06-03

    A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

  9. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, Cressie E. (Farragut, TN); Seals, Roland D. (Oak Ridge, TN); Price, R. Eugene (Knoxville, TN)

    1997-01-01

    A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

  10. Modelling of pyrolysis of large wood particles.

    PubMed

    Sadhukhan, Anup Kumar; Gupta, Parthapratim; Saha, Ranajit Kumar

    2009-06-01

    A fully transient mathematical model has been developed to describe the pyrolysis of large biomass particles. The kinetic model consists of both primary and secondary reactions. The heat transfer model includes conductive and internal convection within the particle and convective and radiative heat transfer between the external surface and the bulk. An implicit Finite Volume Method (FVM) with Tridiagonal Matrix Algorithm (TDMA) is employed to solve the energy conservation equation. Experimental investigations are carried out for wood fines and large wood cylinder and sphere in an electrically heated furnace under inert atmosphere. The model predictions for temperature and mass loss histories are in excellent agreement with experimental results. The effect of internal convection and particle shrinkage on pyrolysis behaviour is investigated and found to be significant. Finally, simulation studies are carried out to analyze the effect of bulk temperature and particle size on total pyrolysis time and the final yield of char. PMID:19231172

  11. Toxicity of pyrolysis gases from polytetrafluoroethylene

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Schneider, J. E.

    1979-01-01

    A sample of polytetrafluoroethylene was evaluated for toxicity of pyrolysis gases, using various test conditions of the toxicity screening test method developed at the University of San Francisco. Time to death appears to be affected by the material of which the pyrolysis tube is made, with Monel tending to give longer times to death than quartz. When quartz tubes are used, time to death seems to be related to carbon monoxide concentration. When Monel tubes are used, carbon monoxide does not appear to be the principal toxicant.

  12. Synthesis, characterization and ellipsometric study of ultrasonically sprayed Co3O4 films

    NASA Astrophysics Data System (ADS)

    Gençyılmaz, O.; Taşköprü, T.; Atay, F.; Akyüz, İ.

    2015-10-01

    In the present study, cobalt oxide (Co3O4) films were produced using ultrasonic spray pyrolysis technique onto the glass substrate at different temperatures (200-250-300-350 °C). The effect of substrate temperature on the structural, optical, surface and electrical properties of Co3O4 films was reported. Thickness, refractive index and extinction coefficient of the films were determined by spectroscopic ellipsometry, and X-ray diffraction analyses revealed that Co3O4 films were polycrystalline fcc structure and the substrate temperature significantly improved the crystal structure of Co3O4 films. The films deposited at 350 °C substrate temperature showed the best structural quality. Transmittance, absorbance and reflectance spectra were taken by means of UV-Vis spectrophotometer, and optical band gap values were calculated using optical method. Surface images and roughness values of the films were taken by atomic force microscopy to see the effect of deposition temperature on surface properties. The resistivity of the films slightly decreases with increase in the substrate temperature from 1.08 × 104 to 1.46 × 102 Ω cm. Finally, ultrasonic spray pyrolysis technique allowed production of Co3O4 films, which are alternative metal oxide film for technological applications, at low substrate temperature.

  13. Evaluation of optical parameters and characterization of ultrasonically sprayed MgO films by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Kurtaran, S.; Akyuz, I.; Atay, F.

    2013-01-01

    MgO is a chemically stable buffer layer and a good candidate with its unique optical and structural characteristics such as low refractive index and good lattice matching for the deposition of technologically important materials. In this work, we have produced MgO films by a low cost ultrasonic spray pyrolysis technique and tried to improve their characteristics by thermal annealing. MgO films have been obtained on glass substrates at 325 ± 5 °C and annealed at two different temperatures as 500 °C and 600 °C for 2 h. Elemental analyses have been made by energy-dispersive X-ray spectroscopy. Thicknesses, refractive indices and extinction coefficient values have been determined by spectroscopic ellipsometry technique using Cauchy-Urbach model. Band gap values of the films have been calculated using the absorbance spectra and optical method. X-ray diffraction patterns have been used to investigate the structural properties and to calculate lattice parameters. Atomic force microscope images have been taken to see the effect of thermal annealing on surface morphology. Electrical resistivity values of the films have been determined using a four-point probe set-up. As a result, annealing temperature has a strong effect on the mentioned properties and a low cost ultrasonic spray pyrolysis technique allows the production of new and alternative MgO buffer layers for technological applications.

  14. Pyrolysis of the tetra pak

    SciTech Connect

    Korkmaz, Ahmet; Yanik, Jale Brebu, Mihai; Vasile, Cornelia

    2009-11-15

    This study deals with pyrolysis of tetra pak which is widely used as an aseptic beverage packaging material. Pyrolysis experiments were carried out under inert atmosphere in a batch reactor at different temperatures and by different pyrolysis modes (one- and two-step). The yields of char, liquid and gas were quantified. Pyrolysis liquids produced were collected as three separate phases; aqueous phase, tar and polyethylene wax. Characterization of wax and the determination of the total amount of phenols in aqueous phase were performed. Chemical compositions of gas and char products relevant to fuel applications were determined. Pure aluminum can be also recovered by pyrolysis.

  15. Development of an efficient transformation method by Agrobacterium tumefaciens and high throughput spray assay to identify transgenic plants for woodland strawberry (Fragaria vesca) using NPTII selection.

    PubMed

    Pantazis, Christopher J; Fisk, Sarah; Mills, Kerri; Flinn, Barry S; Shulaev, Vladimir; Veilleux, Richard E; Dan, Yinghui

    2013-03-01

    KEY MESSAGE : We developed an efficient Agrobacterium -mediated transformation method using an Ac/Ds transposon tagging construct for F. vesca and high throughput paromomycin spray assay to identify its transformants for strawberry functional genomics. Genomic resources for Rosaceae species are now readily available, including the Fragaria vesca genome, EST sequences, markers, linkage maps, and physical maps. The Rosaceae Genomic Executive Committee has promoted strawberry as a translational genomics model due to its unique biological features and transformability for fruit trait improvement. Our overall research goal is to use functional genomic and metabolic approaches to pursue high throughput gene discovery in the diploid woodland strawberry. F. vesca offers several advantages of a fleshy fruit typical of most fruit crops, short life cycle (seed to seed in 12-16weeks), small genome size (206Mbb/C), small plant size, self-compatibility, and many seeds per plant. We have developed an efficient Agrobacterium tumefaciens-mediated strawberry transformation method using kanamycin selection, and high throughput paromomycin spray assay to efficiently identify transgenic strawberry plants. Using our kanamycin transformation method, we were able to produce up to 98 independent kanamycin resistant insertional mutant lines using a T-DNA construct carrying an Ac/Ds transposon Launchpad system from a single transformation experiment involving inoculation of 22 leaf explants of F. vesca accession 551572 within approx. 11weeks (from inoculation to soil). Transgenic plants with 1-2 copies of a transgene were confirmed by Southern blot analysis. Using our paromomycin spray assay, transgenic F. vesca plants were rapidly identified within 10days after spraying. PMID:23160638

  16. Microemulsion flame pyrolysis for hopcalite nanoparticle synthesis: a new concept for catalyst preparation.

    PubMed

    Biemelt, T; Wegner, K; Teichert, J; Kaskel, S

    2015-04-01

    A new route to highly active hopcalite catalysts via flame spray pyrolysis of an inverse microemulsion precursor is reported. The nitrate derived nanoparticles are around 15 nm in diameter and show excellent conversion of CO under ambient conditions, outperforming commercial reference hopcalite materials produced by co-precipitation. PMID:25726946

  17. Rapid habitability assessment of Mars samples by pyrolysis-FTIR

    NASA Astrophysics Data System (ADS)

    Gordon, Peter R.; Sephton, Mark A.

    2016-02-01

    Pyrolysis Fourier transform infrared spectroscopy (pyrolysis FTIR) is a potential sample selection method for Mars Sample Return missions. FTIR spectroscopy can be performed on solid and liquid samples but also on gases following preliminary thermal extraction, pyrolysis or gasification steps. The detection of hydrocarbon and non-hydrocarbon gases can reveal information on sample mineralogy and past habitability of the environment in which the sample was created. The absorption of IR radiation at specific wavenumbers by organic functional groups can indicate the presence and type of any organic matter present. Here we assess the utility of pyrolysis-FTIR to release water, carbon dioxide, sulfur dioxide and organic matter from Mars relevant materials to enable a rapid habitability assessment of target rocks for sample return. For our assessment a range of minerals were analyzed by attenuated total reflectance FTIR. Subsequently, the mineral samples were subjected to single step pyrolysis and multi step pyrolysis and the products characterised by gas phase FTIR. Data from both single step and multi step pyrolysis-FTIR provide the ability to identify minerals that reflect habitable environments through their water and carbon dioxide responses. Multi step pyrolysis-FTIR can be used to gain more detailed information on the sources of the liberated water and carbon dioxide owing to the characteristic decomposition temperatures of different mineral phases. Habitation can be suggested when pyrolysis-FTIR indicates the presence of organic matter within the sample. Pyrolysis-FTIR, therefore, represents an effective method to assess whether Mars Sample Return target rocks represent habitable conditions and potential records of habitation and can play an important role in sample triage operations.

  18. ENGINEERING BULLETIN: PYROLYSIS TREATMENT

    EPA Science Inventory

    Pyrolysis is formally defined as chemical decomposition induced in organic materials by heat in the absence of oxygen. In practice, it is not possible to achieve a completely oxygen-free atmosphere; actual pyrolytic systems are operated with less than stoichiometric quantities of...

  19. Agricultural Spraying

    NASA Technical Reports Server (NTRS)

    1986-01-01

    AGDISP, a computer code written for Langley by Continuum Dynamics, Inc., aids crop dusting airplanes in targeting pesticides. The code is commercially available and can be run on a personal computer by an inexperienced operator. Called SWA+H, it is used by the Forest Service, FAA, DuPont, etc. DuPont uses the code to "test" equipment on the computer using a laser system to measure particle characteristics of various spray compounds.

  20. Toxicity of pyrolysis gases from foam plastics

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.; Casey, C. J.

    1980-01-01

    Twenty-three samples of flexible foams and twelve samples of rigid foams were evaluated for toxicity of pyrolysis gases, using the USF toxicity screening test method. Polychloroprene among the flexible foams, and polystyrene among the rigid foams, appeared to exhibit the least toxicity under these particular test conditions.

  1. Toxicity of pyrolysis gases from polypropylene

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Schneider, J. E.; Brauer, D. F.

    1979-01-01

    A sample of polypropylene was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. The gases from this sample appeared to be equivalent or less toxic than the gases from a sample of polyethylene under these particular test conditions. Carbon monoxide appeared to be the principal toxicant.

  2. Peaceful pyrolysis-a novel method for the decomposition of metal-perchlorate complexes of organic ligands.

    PubMed

    Nair, M R; Kurian, M J; Prabhakaran, C P

    1981-06-01

    Perchlorate complexes of vanadium(IV), iron(III), dysprosium, yttrium, copper(II) and nickel with the organic ligands dimethyl sulphoxide, antipyrine, 4-aminoantipyrine, 4-(2-hydroxynaphthyl)-azoantipyrine, and 4-(2,4-dihydroxyphenyl)azoantipyrine have been prepared and analysed for their metal content after decomposition by a non-explosive pyrolytic technique, viz. heating with ammonium chloride. The results obtained agree with those obtained by the standard methods. This pyrolytic technique is found to be very convenient, rapid and accurate. PMID:18962945

  3. Effect of whey protein isolate and ?-cyclodextrin wall systems on stability of microencapsulated vanillin by spray-freeze drying method.

    PubMed

    Hundre, Swetank Y; Karthik, P; Anandharamakrishnan, C

    2015-05-01

    Vanillin flavour is highly volatile in nature and due to that application in food incorporation is limited; hence microencapsulation of vanillin is an ideal technique to increase its stability and functionality. In this study, vanillin was microencapsulated for the first time by non-thermal spray-freeze-drying (SFD) technique and its stability was compared with other conventional techniques such as spray drying (SD) and freeze-drying (FD). Different wall materials like ?-cyclodextrin (?-cyd), whey protein isolate (WPI) and combinations of these wall materials (?-cyd + WPI) were used to encapsulate vanillin. SFD microencapsulated vanillin with WPI showed spherical shape with numerous fine pores on the surface, which in turn exhibited good rehydration ability. On the other hand, SD powder depicted spherical shape without pores and FD encapsulated powder yielded larger particle sizes with flaky structure. FTIR analysis confirmed that there was no interaction between vanillin and wall materials. Moreover, spray-freeze-dried vanillin + WPI sample exhibited better thermal stability than spray dried and freeze-dried microencapsulated samples. PMID:25529646

  4. Production of p-xylene from biomass by catalytic fast pyrolysis using ZSM-5 catalysts with reduced pore openings.

    PubMed

    Cheng, Yu-Ting; Wang, Zhuopeng; Gilbert, Christopher J; Fan, Wei; Huber, George W

    2012-10-29

    Pores for thought: Chemical liquid deposition of silica onto ZSM-5 catalysts led to smaller pore openings that resulted in >90% selectivity for p-xylene over the other xylenes in the catalytic fast pyrolysis of furan and 2-methylfuran (see scheme). The p-xylene selectivity increased from 51% with gallium spray-dried ZSM-5 to 72% with a pore-mouth-modified catalyst in the pyrolysis of pine wood. PMID:23038098

  5. Additives initiate selective production of chemicals from biomass pyrolysis.

    PubMed

    Leng, Shuai; Wang, Xinde; Wang, Lei; Qiu, Huizhe; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo; Ma, Fengyun; Liu, Jingmei; Wang, Qiang

    2014-03-01

    To improve chemicals selectivity under low temperature, a new method that involves the injection of additives into biomass pyrolysis is introduced. This method allows biomass pyrolysis to achieve high selectivity to chemicals under low temperature (300C), while nothing was obtained in typical pyrolysis under 300C. However, by using the new method, the first liquid drop emerged at the interval between 140C and 240C. Adding methanol to mushroom scrap pyrolysis obtained high selectivity to acetic acid (98.33%), while adding ethyl acetate gained selectivity to methanol (65.77%) in bagasse pyrolysis and to acetone (72.51%) in corncob pyrolysis. Apart from basic chemicals, one high value-added chemical (2,3-dihydrobenzofuran) was also detected, which obtained the highest selectivity (10.33%) in corncob pyrolysis through the addition of ethyl acetate. Comparison of HZSM-5 and CaCO3 catalysis showed that benzene emerged in the liquid because of the larger degree of cracking and hydrodeoxygenation over HZSM-5. PMID:24508091

  6. Method of forming a leak proof plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Kuo, Lewis J. H. (Monroeville, PA); Vora, Shailesh D. (Monroeville, PA)

    1995-01-01

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an electrode structure of an electrochemical cell by: (A) providing an electrode structure; (B) forming on a selected portion of the electrode surface, an interconnection layer having the general formula La.sub.1-x M.sub.x Cr.sub.1-y N.sub.y O.sub.3, where M is a dopant selected from the group of Ca, Sr, Ba, and mixtures thereof, and where N is a dopant selected from the group of Mg, Co, Ni, Al, and mixtures thereof, and where x and y are each independently about 0.075-0.25, by thermally spraying, preferably plasma arc spraying, a flux added interconnection spray powder, preferably agglomerated, the flux added powder comprising flux particles, preferably including dopant, preferably (CaO).sub.12. (Al.sub.2 O.sub.3).sub.7 flux particles including Ca and Al dopant, and LaCrO.sub.3 interconnection particles, preferably undoped LaCrO.sub.3, to form a dense and substantially gas-tight interconnection material bonded to the electrode structure by a single plasma spraying step; and, (C) heat treating the interconnection layer at from about 1200.degree. to 1350.degree. C. to further densify and heal the micro-cracks and macro-cracks of the thermally sprayed interconnection layer. The result is a substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode structure. The electrode structure can be an air electrode, and a solid electrolyte layer can be applied to the unselected portion of the air electrode, and further a fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell for generation of electrical power.

  7. Method of forming a leak proof plasma sprayed interconnection layer on an electrode of an electrochemical cell

    DOEpatents

    Kuo, L.J.H.; Vora, S.D.

    1995-02-21

    A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an electrode structure of an electrochemical cell by: (A) providing an electrode structure; (B) forming on a selected portion of the electrode surface, an interconnection layer having the general formula La{sub 1{minus}x}M{sub x}Cr{sub 1{minus}y}N{sub y}O{sub 3}, where M is a dopant selected from the group of Ca, Sr, Ba, and mixtures thereof, and where N is a dopant selected from the group of Mg, Co, Ni, Al, and mixtures thereof, and where x and y are each independently about 0.075--0.25, by thermally spraying, preferably plasma arc spraying, a flux added interconnection spray powder, preferably agglomerated, the flux added powder comprising flux particles, preferably including dopant, preferably (CaO){sub 12}(Al{sub 2}O{sub 3}){sub 7} flux particles including Ca and Al dopant, and LaCrO{sub 3} interconnection particles, preferably undoped LaCrO{sub 3}, to form a dense and substantially gas-tight interconnection material bonded to the electrode structure by a single plasma spraying step; and (C) heat treating the interconnection layer at from about 1,200 to 1,350 C to further densify and heal the micro-cracks and macro-cracks of the thermally sprayed interconnection layer. The result is a substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode structure. The electrode structure can be an air electrode, and a solid electrolyte layer can be applied to the unselected portion of the air electrode, and further a fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell for generation of electrical power. 4 figs.

  8. Using different chemical methods for deposition of copper selenide thin films and comparison of their characterization.

    PubMed

    Güzeldir, Betül; Sağlam, Mustafa

    2015-11-01

    Different chemical methods such as Successive Ionic Layer Adsorption and Reaction (SILAR), spin coating and spray pyrolysis methods were used to deposite of copper selenide thin films on the glass substrates. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDX) spectroscopy and UV-vis spectrophotometry. The XRD and SEM studies showed that all the films exhibit polycrystalline nature and crystallinity of copper selenide thin films prepared with spray pyrolysis greater than spin coating and SILAR methods. From SEM and AFM images, it was observed copper selenide films were uniform on the glass substrates without any visible cracks or pores. The EDX spectra showed that the expected elements exist in the thin films. Optical absorption studies showed that the band gaps of copper selenide thin films were in the range 2.84-2.93 eV depending on different chemical methods. The refractive index (n), optical static and high frequency dielectric constants (ε0, ε∞) values were calculated by using the energy bandgap values for each deposition method. The obtained results from different chemical methods revealed that the spray pyrolysis technique is the best chemical deposition method to fabricate copper selenide thin films. This absolute advantage was lead to play key roles on performance and efficiency electrochromic and photovoltaic devices. PMID:26037495

  9. Temperature control system for pyrolysis furnace

    SciTech Connect

    Heran, R.F.; Koptis, R.A.

    1987-03-17

    This patent describes a batch-type pyrolysis furnace having a main chamber, a main gas burner to directly heat air ducted into the chamber, and a throat near the top of the main chamber through which throat organic vapor volatilized by pyrolysis of polymerbonded metal parts leave the main chamber. It also has an afterburner chamber provided with an afterburner to incinerate the organic vapor downstream of the throat, and, an exhaust stack through which incinerated vapor is vented. The improvement described here comprises: a first temperature sensing means, located within the main chamber, near the top thereof, to sense the instantaneous ambient temperature of gases above the metal parts therewithin; a second temperature sensing means, located in the exhaust stack downstream of the afterburner operatively connected to the main burner for attenuated or on/off operation thereof; a third temperature sensing means, located in the throat upstream of the afterburner the throat having an area, and the main chamber having a volume which are related such that their ratio is always greater than the critical vent number 0.005/ft. and water spray means responsive only to the first and/or third temperature sensing means when either the temperature in the main chamber exceeds a predetermined critical ambient temperature in the range from about 600/sup 0/-900/sup 0/F, or the temperature in the throat is at least about 50/sup 0/F higher than the ambient temperature.

  10. Magnetic metal-organic frameworks: γ-Fe2O3@MOFs via confined in situ pyrolysis method for drug delivery.

    PubMed

    Wu, Yi-nan; Zhou, Meimei; Li, Shu; Li, Zehua; Li, Jie; Wu, Baozhen; Li, Guangtao; Li, Fengting; Guan, Xiaohong

    2014-07-23

    A general one-step in situ pyrolysis route for the construction of metal-organic frameworks encapsulating superparamagnetic γ-Fe2O3NPs dispersed in the confined cavities of MOFs homogeneously is described. The integration of γ-Fe2O3 NPs or clusters into MOFs can endow these porous materials with superparamagnetic element. By the combination of the thermal stability of MOFs and pyrolysis of metal triacetylacetonate complex at matched conditions, the porous structure of MOFs are well maintained while the size-induced superparamagnetic property of nano γ-Fe2O3 is obtained. As a proof of concept, both the γ- Fe2O3@ZIF-8 and γ-Fe2O3@MIL-53(Al) were successfully prepared, and the latter was chosen to demonstrate its potential drug delivery as a magnetic MOF. PMID:24644065

  11. Pyrolysis process and apparatus

    DOEpatents

    Lee, Chang-Kuei (Sewell, NJ)

    1983-01-01

    This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

  12. Acidity of biomass fast pyrolysis bio-oils

    SciTech Connect

    Oasmaa, Anja; Elliott, Douglas C.; Korhonen, Jaana

    2010-12-17

    The use of the TAN method for measuring the acidity of biomass fast pyrolysis bio-oil was evaluated. Suggestions for carrying out the analysis have been made. The TAN method by ASTM D664 or D3339 can be used for measuring the acidity of fast pyrolysis bio-oils and their hydrotreating products. The main difference between the methods is that ASTM D664 is specified for higher TAN values than ASTM D3339. Special focus should be placed on the interpretation of the TAN curves because they differ significantly from those of mineral oils. The curve for bio-oils is so gentle that the automatic detection may not observe the end point properly and derivatization should be used. The acidity of fast pyrolysis bio-oils is mainly derived (60-70%) from volatile acids. Other groups of compounds in fast pyrolysis bio-oils that influence acidity include phenolics, fatty and resin acids, and hydroxy acids.

  13. Pyrolysis-photoionization mass spectrometry

    SciTech Connect

    Bookwalter, C.W.; Zoller, D.L.; Johnston, M.V.

    1995-12-31

    Pyrolysis mass spectrometry has been performed by photoionization with coherent vacuum ultraviolet (VUV) radiation. Pyrolysis mass spectra are often difficult to interpret owing to the complex distribution of ions formed. Much of this complexity can be ascribed to the heterogeneity of samples typically analyzed or to the numerous reaction pathways accompanying pyrolysis. Indeed, information of this type is often the goal of a pyrolysis experiment. However, fragmentation induced by the ionization process can also be extensive and often obscures useful information, VUV photoionization with 9.6 to 10.5 eV radiation minimizes fragmentation by photoionizing just above the ionization threshold.

  14. On methane pyrolysis special applications

    NASA Astrophysics Data System (ADS)

    Toncu, D. C.; Toncu, G.; Soleimani, S.

    2015-11-01

    Methane pyrolysis represents one of the most important processes in industrial use, with applications rising from the chemical and petrochemical industry, combustion, materials and protective coatings. Despite the intense research, experimental data lack kinetic aspects, and the thermodynamics involved often leads to inaccurate results when applied to various systems. Carrying out a comparative analysis of several available data on methane pyrolysis, the paper aims to study the phenomenon of methane pyrolysis under different environments (combustion and plasma), concluding on the most possible reaction pathways involved in many of its applications. Computer simulation using different database underlines the conclusion, helping to the understanding of methane pyrolysis importance in future technologies.

  15. Catalytic pyrolysis of automobile shredder residue

    SciTech Connect

    Arzoumanidis, G.G.; McIntosh, M.J.; Steffensen, E.J.

    1995-07-01

    In the United States, approximately 10 million automobiles are scrapped and shredded each year. The mixture of plastics and other materials remaining after recovery of the metals is known as Automobile Shredder Residue (ASR). In 1994, about 3.5 million tons of ASR was produced and disposed of in landfills. However, environmental, legislative, and economic considerations are forcing the industry to search for recycling or other alternatives to disposal. Numerous studies have been done relating the ASR disposal problem to possible recycling treatments such as pyrolysis, gasification, co-liquefaction of ASR with coal, chemical recovery of plastics from ASR, catalytic pyrolysis, reclamation in molten salts, and vacuum pyrolysis. These and other possibilities have been studied intensively, and entire symposia have been devoted to the problem. Product mix, yields, toxicology issues, and projected economics of conceptual plant designs based on experimental results are among the key elements of past studies. Because the kinds of recycling methods that may be developed, along with their ultimate economic value, depend on a very large number of variables, these studies have been open-ended. It is hoped that it may be useful to explore some of these previously studied areas from fresh perspectives. One such approach, currently under development at Argonne National Laboratory, is the catalytic pyrolysis of ASR.

  16. The tin precursors and hydrogen peroxide effects on spray-deposited SnO2:F-(n)Si solar cells

    NASA Astrophysics Data System (ADS)

    Adnane, M.; Cachet, H.; Folcher, G.; Hamzaoui, S.; Sahraoui, T.; Bouderbala, M.; Zerdali, M.

    2011-10-01

    The oxide semiconductor compounds such as SnO2, In2O3, ITO, ZnO and others brought about a new attention for the metal-insulator-semiconductor structures as photovoltaic converters because of the high values of transmission and conductivity and the possibility of metal replacement in above-mentioned structures. The characteristics of the solar cells based on these oxide semiconductor compounds can be improved with conductivity increasing of the transparent semiconductor films and that is why the purpose of this paper is obtaining of F-doped tin oxide thin films, preparation of SnO2:F-Si solar cells and studying of their properties. The F-doped tin oxide thin films were prepared by spray pyrolysis technique [1-8]. This method was chosen because of the simplicity of the apparatus and relatively low cost. Aqueous solutions containing 0.1 M (TT, BTT or DTD) and 0.07 M NH4F (in the case of doping with F) have been sprayed by an atomizer on Si or glass substrates, heated up to 420 C by maintaining the spray liquid volume, the spray time and the pressure of the carrier gas. Spray pyrolysis deposition of transparent and conductive SnO2 is a low-cost and very flexible technique applicable to solar cells. For SnO2, the drawback is that polycrystalline films are only obtained at relatively high deposition temperatures, largely above 450 C. This constraint may cause damage to the photovoltaic junction. In the present work, it will be demonstrated that the photovoltaic parameters can be influenced by adding small amounts of hydrogen peroxide (H2O2) to the source solution.

  17. Detection of segmentation cracks in top coat of thermal barrier coatings during plasma spraying by non-contact acoustic emission method

    NASA Astrophysics Data System (ADS)

    Ito, Kaita; Kuriki, Hitoshi; Araki, Hiroshi; Kuroda, Seiji; Enoki, Manabu

    2014-06-01

    Numerous cracks can be observed in the top coat of thermal barrier coatings (TBCs) deposited by the atmospheric plasma spraying (APS) method. These cracks can be classified into vertical and horizontal ones and they have opposite impact on the properties of TBCs. Vertical cracks reduce the residual stress in the top coat and provide strain tolerance. On the contrary, horizontal cracks trigger delamination of the top coat. However, monitoring methods of cracks generation during APS are rare even though they are strongly desired. Therefore, an in situ, non-contact and non-destructive evaluation method for this objective was developed in this study with the laser acoustic emission (AE) technique by using laser interferometers as a sensor. More AE events could be detected by introducing an improved noise reduction filter and AE event detection procedures with multiple thresholds. Generation of vertical cracks was successfully separated from horizontal cracks by a newly introduced scanning pattern of a plasma torch. Thus, generation of vertical cracks was detected with certainty by this monitoring method because AE events were detected only during spraying and a positive correlation was observed between the development degree of vertical cracks and the total AE energy in one experiment.

  18. Comparative study on pyrolysis of lignocellulosic and algal biomass using a thermogravimetric and a fixed-bed reactor.

    PubMed

    Yuan, Ting; Tahmasebi, Arash; Yu, Jianglong

    2014-10-28

    Pyrolysis characteristics of four algal and lignocellulosic biomass samples were studied by using a thermogravimetric analyzer (TGA) and a fixed-bed reactor. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. The average activation energy for pyrolysis of biomass samples by FWO and KAS methods in this study were in the range of 211.09-291.19kJ/mol. CO2 was the main gas component in the early stage of pyrolysis, whereas H2 and CH4 concentrations increased with increasing pyrolysis temperature. Bio-oil from Chlorellavulgaris showed higher content of nitrogen containing compounds compared to lignocellulosic biomass. The concentration of aromatic organic compounds such as phenol and its derivatives were increased with increasing pyrolysis temperature up to 700C. FTIR analysis results showed that with increasing pyrolysis temperature, the concentration of OH, CH, CO, OCH3, and CO functional groups in char decreased sharply. PMID:25459840

  19. Modification of light absorption in thin CuInS2 films by sprayed Au nanoparticles.

    PubMed

    Katerski, Atanas; Krber, Erki; Acik, Ilona Oja; Dolgov, Leonid; Mere, Arvo; Sildos, Ilmo; Mikli, Valdek; Krunks, Malle

    2014-12-01

    The chemical spray pyrolysis method was used to deposit CuInS2 (CIS) thin films and Au nanoparticles (NPs) in two configurations: glass/Au-NP layer covered with CuInS2 film (Au-NP/CIS) and glass/CuInS2 films covered with Au-NP layer (CIS/Au-NP). According to X-ray diffraction (XRD), the spray of 2 mM HAuCl4 aqueous solution with a volume of 2.5 to 15 ml onto a glass substrate at 340C results in metallic Au nanoparticles with a similar mean crystallite size in the range of 30?-?38 nm. The mean crystallite sizes remain in the range of 15?-?20 nm when grown onto a CIS film. The prepared films show plasmonic light absorption with increasing intensity in the spectral range of 500- 800 nm when increasing the volume of HAuCl4 solution sprayed. When compared to bare CIS on glass, the absorptance was increased ca. 4.5 times in the case of glass/Au-NP/CIS and ca. 3 times in the case of glass/CIS/Au-NP configuration. The glass/Au-NP/CIS configuration had an advantage since Au-NP could be embedded without chemically damaging the CIS. PMID:26088996

  20. Modification of light absorption in thin CuInS2 films by sprayed Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Katerski, Atanas; Krber, Erki; Acik, Ilona Oja; Dolgov, Leonid; Mere, Arvo; Sildos, Ilmo; Mikli, Valdek; Krunks, Malle

    2014-09-01

    The chemical spray pyrolysis method was used to deposit CuInS2 (CIS) thin films and Au nanoparticles (NPs) in two configurations: glass/Au-NP layer covered with CuInS2 film (Au-NP/CIS) and glass/CuInS2 films covered with Au-NP layer (CIS/Au-NP). According to X-ray diffraction (XRD), the spray of 2 mM HAuCl4 aqueous solution with a volume of 2.5 to 15 ml onto a glass substrate at 340C results in metallic Au nanoparticles with a similar mean crystallite size in the range of 30 - 38 nm. The mean crystallite sizes remain in the range of 15 - 20 nm when grown onto a CIS film. The prepared films show plasmonic light absorption with increasing intensity in the spectral range of 500- 800 nm when increasing the volume of HAuCl4 solution sprayed. When compared to bare CIS on glass, the absorptance was increased ca. 4.5 times in the case of glass/Au-NP/CIS and ca. 3 times in the case of glass/CIS/Au-NP configuration. The glass/Au-NP/CIS configuration had an advantage since Au-NP could be embedded without chemically damaging the CIS.

  1. Development and beyond: Strategy for long-term maintenance of an online laser diffraction particle size method in a spray drying manufacturing process.

    PubMed

    Medendorp, Joseph; Bric, John; Connelly, Greg; Tolton, Kelly; Warman, Martin

    2015-08-10

    The purpose of this manuscript is to present the intended use and long-term maintenance strategy of an online laser diffraction particle size method used for process control in a spray drying process. A Malvern Insitec was used for online particle size measurements and a Malvern Mastersizer was used for offline particle size measurements. The two methods were developed in parallel with the Mastersizer serving as the reference method. Despite extensive method development across a range of particle sizes, the two instruments demonstrated different sensitivities to material and process changes over the product lifecycle. This paper will describe the procedure used to ensure consistent alignment of the two methods, thus allowing for continued use of online real-time laser diffraction as a surrogate for the offline system over the product lifecycle. PMID:25958139

  2. Arc spraying in China

    NASA Astrophysics Data System (ADS)

    Liu, Xianjun

    2001-03-01

    Although are spraying is not a new technique, recent development of arc spraying device systems, spray wires, research on the coating mechanism, and the dynamic behavior of spraying make it a most active thermal spray process. In China, the arc spraying technique is the most efficient way for long life corrosion protection of steel structures. In addition, the arc spraying process is widely used for renovation and surface modification of machine components, mold making for plastic products, high-temperature corrosion resistance for waterwalls of boilers, antisliding coatings, self-lubricating coatings, etc.

  3. Ambient temperature operated acetaldehyde vapour detection of spray deposited cobalt doped zinc oxide thin film.

    PubMed

    Shalini, S; Balamurugan, D

    2016-03-15

    Undoped and Co-doped ZnO thin films were prepared by a home built spray pyrolysis method. X-ray diffraction results indicate that both undoped and Co-doped ZnO have a polycrystalline nature and a preferential orientation peak in the (002) plane. From a field-emission scanning electron micrographs of annealed films, a uniform distribution of nanoparticles along with nanorods was observed. UV-Visible measurement indicated that all the films are transparent in the visible region. The electrical resistance was also reported. The acetaldehyde sensing behaviour of the prepared undoped and Co-doped ZnO thin films was studied using the chemi-resistive method at ambient temperature (∼30°C). In the presence of 10ppm of acetaldehyde vapour, the Co-doped ZnO thin films showed good sensing response of 74% with fast response and recovery time of 3s and 110s respectively. PMID:26748067

  4. Corrosivity Of Pyrolysis Oils

    SciTech Connect

    Keiser, James R; Bestor, Michael A; Lewis Sr, Samuel Arthur; Storey, John Morse

    2011-01-01

    Pyrolysis oils from several sources have been analyzed and used in corrosion studies which have consisted of exposing corrosion coupons and stress corrosion cracking U-bend samples. The chemical analyses have identified the carboxylic acid compounds as well as the other organic components which are primarily aromatic hydrocarbons. The corrosion studies have shown that raw pyrolysis oil is very corrosive to carbon steel and other alloys with relatively low chromium content. Stress corrosion cracking samples of carbon steel and several low alloy steels developed through-wall cracks after a few hundred hours of exposure at 50 C. Thermochemical processing of biomass can produce solid, liquid and/or gaseous products depending on the temperature and exposure time used for processing. The liquid product, known as pyrolysis oil or bio-oil, as produced contains a significant amount of oxygen, primarily as components of water, carboxylic acids, phenols, ketones and aldehydes. As a result of these constituents, these oils are generally quite acidic with a Total Acid Number (TAN) that can be around 100. Because of this acidity, bio-oil is reported to be corrosive to many common structural materials. Despite this corrosive nature, these oils have the potential to replace some imported petroleum. If the more acidic components can be removed from this bio-oil, it is expected that the oil could be blended with crude oil and then processed in existing petroleum refineries. The refinery products could be transported using customary routes - pipelines, barges, tanker trucks and rail cars - without a need for modification of existing hardware or construction of new infrastructure components - a feature not shared by ethanol.

  5. Vapor phase pyrolysis

    NASA Technical Reports Server (NTRS)

    Steurer, Wolfgang

    1992-01-01

    The vapor phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is vaporized and the vapor is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated vapor to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the pressure differential between the vaporization region and the oxygen collection system with the aid of the environmental vacuum.

  6. Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.

    PubMed

    Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun

    2013-05-01

    Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate. PMID:23858864

  7. Defect detection in multi-layered, plasma sprayed zirconia by time resolved infrared radiometry: A comparison between analytical and experimental methods

    SciTech Connect

    Happoldt, P.G.; Ellingson, W.A.; Gardiner, T.; Krueger, J.

    1994-04-01

    Analytical and experimental methods were used to study a series of test specimens consisting of plasma sprayed layers of NiCrA1Y/ZrO{sub 2} of various compositions.The coatings were seeded with artificial defects and were sprayed on steel disks. Two types of defects were used: flat bottomed holes drilled in the steel substrate and patches of room temperature vulcanizing silicone within the coatings. Defect sizes ranged from 0.1 to 10 mm and were at depths below the coating surface from 0.6 to 3.6 min. The method of time resolved infrared radiometry was used with two different heat sources, an acetylene torch and a high intensity lamp, to inspect the coatings. The torch allowed excellent sensitivity at depths of less than 2 mm and the lamp revealed flaws through the full coating thickness. Two analytical models were developed to study beat flow in the test specimens: a finite element model and an electrical analog model. Results from the two models were compared to check consistency and the finite element model results were compared with experimental results. The finite element code was chosen for further development due to its greater flexibility and ease of use.

  8. Research on air sprays and unique foam application methods. Phase II report. Laboratory investigation of foam systems

    SciTech Connect

    Not Available

    1982-06-01

    The objective of this study is to assess the effectiveness of air sprays and foam systems for dust control on longwall double-drum shearer faces. Laboratory testing has been conducted using foam systems and promising results have been obtained. Upon Bureau approval, underground testing will be scheduled to assess the effectiveness of foam systems under actual operating conditions. Laboratory testing of air sprays is being conducted at present. This report presents the results of the laboratory testing of foam systems. Specifically, the results obtained on the evaluation of selected foaming agents are presented, the feasibility investigation of flushing foam through the shearer-drum are demonstrated, and conceptual layout of the foam system on the shearer is discussed. The laboratory investigation of the selected foaming agents reveal that the Onyx Microfoam, Onyx Maprosyl and DeTer Microfoam foaming agents have higher expansion ratios compared to the others tested. Flushing foam through the shearer drum is entirely feasible and could be a viable technique for dust suppression on longwall faces.

  9. Plasma spray processing of TBC`s

    SciTech Connect

    Herman, H.; Berndt, C.C.

    1995-10-01

    Thermal spray processing has been used for a number of years to cost-effectively apply TBC`s for a wide range of heat engine applications. In particular, bond coats are applied by vacuum plasma spray or HVOF techniques and partially-stabilized zirconia top coats are applied by plasma spray methods. Thermal spray involves melting and rapid transport of the molten particles to the substrate, where high-rate solidification and coating build-up occur. It is the very nature of this melt processing that leads to the unique layered microstructure, as well as the apparent imperfections, so readily identified with thermal spray. Therefore, although the plasma spray of TBCs has been largely successful, it is clear that a major step forward in terms of reliability and performance can be gained by a fundamental understanding of the TBC microstructure with respect to the processing technology and operating environment.

  10. One-step synthesis of core-shell (Ce0.7Zr0.3O2)(x)(Al2O3)(1-x) [(Ce0.7Zr0.3O2)@Al2O3] nanopowders via liquid-feed flame spray pyrolysis (LF-FSP).

    PubMed

    Kim, Min; Laine, Richard M

    2009-07-01

    We report here the synthesis of Ce(x)Zr(1-x)O(2) and (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) core-shell nanopowders in a single step by liquid-feed flame spray pyrolysis (LF-FSP) of the metalloorganic precursors, Ce(O(2)CCH(2)CH(3))(3)(OH), alumatrane [N(CH(2)CH(2)O)(3)Al], and Zr(O(2)CCH(2)CH(3))(2)(OH)(2). Solutions of all three precursors in ethanol with ceramic yields of 2.5 wt% were aerosolized with O(2), combusted at temperatures above 1500 degrees C, and rapidly quenched at approximately 1000 degrees C/ms to form Ce(x)Zr(1-x)O(2) and (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) nanopowders of selected compositions, at rates of 50-100 g/h. The resulting, as-processed, materials are unaggregated nanopowders with average particle sizes (APSs) < 20 nm and corresponding specific surface areas of 30-50 m(2)/g. The as-processed powders were characterized in terms of phase, particle size, specific surface area, compositions, and morphology by XRD, BET, DLS, SEM, TEM, XPS, TGA-DTA, and FT-IR. LF-FSP provides access to binary Ce(x)Zr(1-x)O(2) nanopowders and ternary (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) nanopowders in one step. The obtained Ce(0.7)Zr(0.3)O(2) powders are solid solutions with a cubic phase. In contrast, LF-FSP of mixtures of the three precursors at specific compositions [x = 0.5, 0.7 for (Ce(0.7)Zr(0.3)O(2))(x)@(Al(2)O(3))(1-x)] provide core-shell nanopowders in a single step. The most reasonable explanation is that there are differences in the rates of condensation, nucleation and miscibility between the gas phase ions that form the Ce(x)Zr(1-x)O(2) solid solutions and those that condense to delta-Al(2)O(3) during processing. These as-produced materials are without microporosity at surface areas of > or = 30 m(2)/g. Evidence is presented suggesting the formation of (Ce/Zr)(3+) species in the as-processed (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) core-shell materials. An accompanying paper indicates that these materials offer significant and novel catalytic activities for hydrocarbon oxidation and deNO(x) processes without using platinum as a co-catalyst. PMID:19566096

  11. Extent of pyrolysis impacts on fast pyrolysis biochar properties.

    PubMed

    Brewer, Catherine E; Hu, Yan-Yan; Schmidt-Rohr, Klaus; Loynachan, Thomas E; Laird, David A; Brown, Robert C

    2012-01-01

    A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization. PMID:22751053

  12. Kinetics of scrap tyre pyrolysis under vacuum conditions

    SciTech Connect

    Lopez, Gartzen; Aguado, Roberto; Olazar, Martin Arabiourrutia, Miriam; Bilbao, Javier

    2009-10-15

    Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12 K in the reaction starting temperature. The kinetic constant at 503 K for devolatilization of volatile additives at 0.25 atm is 1.7 times higher than that at 1 atm, and that corresponding to styrene-butadiene rubber at 723 K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.

  13. Kinetics of scrap tyre pyrolysis under vacuum conditions.

    PubMed

    Lopez, Gartzen; Aguado, Roberto; Olazar, Martín; Arabiourrutia, Miriam; Bilbao, Javier

    2009-10-01

    Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12K in the reaction starting temperature. The kinetic constant at 503K for devolatilization of volatile additives at 0.25atm is 1.7 times higher than that at 1atm, and that corresponding to styrene-butadiene rubber at 723K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate. PMID:19589669

  14. Liquid rocket spray combustion stability analysis

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Jeng, San-Mou

    1992-01-01

    A computational approach to the analysis of spray combustion stability in liquid rocket combustors is proposed which is based on the unsteady quasi-two-dimensional Euler equations with interphase source terms derived from a Lagrangian treatment of the combusting spray. Based on a preliminary evaluation, the computational methodology presented here is a promising research tool and a potential design/development aid for investigating the stability characteristics of liquid rocket engines. The method is characterized by low numerical noise; the Lagrangian treatment of the spray offers improved flexibility for the direct modeling of spray combustion.

  15. Very Large Eddy Simulations of a Jet-A Spray Reacting Flow in a Single Element LDI Injector With and Without Invoking an Eulerian Scalar DWFDF Method

    NASA Technical Reports Server (NTRS)

    Shih, Tsan-Hsing; Liu, Nan-Suey

    2013-01-01

    This paper presents the very large eddy simulations (VLES) of a Jet-A spray reacting flow in a single element lean direct injection (LDI) injector by using the National Combustion Code (NCC) with and without invoking the Eulerian scalar DWFDF method, in which DWFDF is defined as the density weighted time filtered fine grained probability density function. The flow field is calculated by using the time filtered compressible Navier-Stokes equations (TFNS) with nonlinear subscale turbulence models, and when the Eulerian scalar DWFDF method is invoked, the energy and species mass fractions are calculated by solving the equation of DWFDF. A nonlinear subscale model for closing the convection term of the Eulerian scalar DWFDF equation is used and will be briefly described in this paper. Detailed comparisons between the results and available experimental data are carried out. Some positive findings of invoking the Eulerian scalar DWFDF method in both improving the simulation quality and maintaining economic computing cost are observed.

  16. Delamination Strength of WC-Co Thermal-Sprayed Coating Under Combined Stresses by Torsion-Tension Pin-Test Method

    NASA Astrophysics Data System (ADS)

    Kaneko, Kenji; Higaki, Keitaro

    2014-08-01

    In this report, the delamination strength of WC -Co thermal-sprayed coatings under combined torsion and tension is evaluated using a newly developed method, which is called the torsion -tension pin-test. First, the effects of both the pin diameter and the coating thickness on the apparent delamination strength were investigated experimentally. Second, the stress distributions around the interface edge between the pin and the coating were numerically obtained by using the finite element analysis program "MARC." It was confirmed that the fractured plane of the torsion pin coincides with the interfacial plane between the coating and the pin. The apparent delamination strength obtained experimentally decreased linearly with increasing pin diameter and increased with increasing coating thickness t, but it was stable at t of 400 μm or more. The shear delamination strength decreased with increasing tensile stress. Similar stress distributions were observed at the interface when delaminations occurred for rather thick coatings, independent of the pin diameter. The critical combination of the strength of shear stress fields ( Ks) with that of tensile stress fields ( Ka), i.e., the delamination criteria of the coating under combined shear and tensile loadings, was obtained for a WC-12Co thermal-sprayed coating. These combinations were found to be independent of pin diameter and coating thickness.

  17. High-performance graphene/sulphur electrodes for flexible Li-ion batteries using the low-temperature spraying method

    NASA Astrophysics Data System (ADS)

    Kumar, Pushpendra; Wu, Feng-Yu; Hu, Lung-Hao; Ali Abbas, Syed; Ming, Jun; Lin, Chia-Nan; Fang, Jason; Chu, Chih-Wei; Li, Lain-Jong

    2015-04-01

    Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (~70% capacity retention after 250 cycles), good coulombic efficiency (~98%) and high capacity (~1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes.Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (~70% capacity retention after 250 cycles), good coulombic efficiency (~98%) and high capacity (~1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00885a

  18. Hydrodechlorination of dichlorobiphenyls over Ni-Mo/Al2O3 catalysts prepared by spray-drying method.

    PubMed

    Gryglewicz, G; Stolarski, M; Gryglewicz, S; Klijanienko, A; Piechocki, W; Hoste, S; Van Driessche, I; Carleer, R; Yperman, J

    2006-01-01

    The hydrodechlorination (HDCl) process of 2,3-, 2,4- and 2,5-dichlorobiphenyls was studied over a sulphided Ni-Mo/Al(2)O(3) catalyst in a stirred autoclave at a hydrogen pressure of 3 MPa. The catalysts were prepared by spray-drying. They were characterized by N(2) adsorption, thermogravimetry and scanning electron microscopy with X-ray microanalysis. The reaction temperature of the catalytic HDCl process was varied in the range of 230-290 degrees C. Polychlorinated biphenyls (PCBs) free transformer oil was used as reaction medium. The HDCl degree of dichlorobiphenyl isomers was in the range of 82-93%. The efficiency in the chlorine removal was found to be related to the position of the substituted chlorine atom and decreased as follows 2,4-dichlorobiphenyl approximately 2,5-dichlorobiphenyl>2,3-dichlorobiphenyl. For comparison, the HDCl process of 2,3-dichlorobiphenyl (2,3-PCB) without catalyst was also studied. The chlorine removal was 85% for the catalytic HDCl of 2,3-PCB whereas non-catalytic process led only to 16% of dechlorination in the same operating conditions, i.e. at 290 degrees C after 120 min. Monodichlorobiphenyls were not detected in the reaction products. The data for both catalytic and non-catalytic conversion of 2,3-PCB fit to a first-order model. Kinetic constants and the activation energy of the overall HDCl reaction of 2,3-PCB to biphenyl were evaluated. Compared to non-catalytic process, a nearly threefold decrease in the activation energy was observed in the presence of Ni-Mo/Al(2)O(3) catalyst prepared by spray-drying (48 kJ mol(-1) vs. 124 kJ mol(-1)). PMID:15949837

  19. Fast Pyrolysis of Agricultural Wastes in a Fluidized Bed Reactor

    NASA Astrophysics Data System (ADS)

    Wang, X. H.; Chen, H. P.; Yang, H. P.; Dai, X. M.; Zhang, S. H.

    Solid biomass can be converted into liquid fuel through fast pyrolysis, which is convenient to be stored and transported with potential to be used as a fossil oil substitute. In China, agricultural wastes are the main biomass materials, whose pyrolysis process has not been researched adequately compared to forestry wastes. As the representative agricultural wastes in China, peanut shell and maize stalk were involved in this paper and pine wood sawdust was considered for comparing the different pyrolysis behaviors of agricultural wastes and forestry wastes. Fast pyrolysis experiments were carried out in a bench-scale fluidized-bed reactor. The bio-oil yieldsof peanut shell and maize stalk were obviously lower than that ofpine sawdust. Compared with pine sawdust, the char yields of peanut shell and maize stalk were higher but the heating value of uncondensable gaswas lower. This means that the bio-oil cost will be higher for agricultural wastes if taking the conventional pyrolysis technique. And the characteristic and component analysis resultsof bio-oil revealed that the quality of bio-oil from agricultural wastes, especially maize stalk, was worse than that from pine wood. Therefore, it is important to take some methods to improve the quality of bio-oilfrom agricultural wastes, which should promote the exploitation of Chinese biomass resources through fast pyrolysis in afluidized bed reactor.

  20. Growth, microstructure, optical and electrical properties of sprayed CuInSe{sub 2} polycrystalline films

    SciTech Connect

    Akl, Alaa A.; Afify, H.H.

    2008-06-03

    Polycrystalline thin films of CuInSe{sub 2} have been prepared by chemical spray pyrolysis technique as a function of Cu/In ratio. Incremental growth of the various ratios followed at different substrate temperatures ranging from 548 to 623 K. Characterizations by means of compositional analysis, X-ray diffraction and spectrophotometry measurements have been carried out. Voigt profile method has been used to determine the microstructure parameter (crystallite/domain size and macrostrain). The effect of Cu/In ratio as well as substrate temperature on the optical features (absorption coefficient and band gap) of these films has been investigated. The films of different Cu/In ratios (0.9-1.1) displayed a band gap from 0.92 to 1.025 eV for direct transition. The dark resistivity measurements at room temperature of Cu-rich samples show about five orders of magnitude higher than that of In-rich samples.

  1. An elastic-perfectly plastic model for simulating an aluminum particle behavior during plasma thermal spraying using the finite element method

    NASA Astrophysics Data System (ADS)

    Benramoul, L.; Abdellah El-Hadj, A.

    2011-11-01

    It is a 2D numerical study which treats the splat and flattening of the droplet during a thermal spraying process. An aluminum particle at a high temperature is impacted on steel substrate. A perfectly elastic-plastic model is used instead of the VOF method which is exclusively used in the literature. For this purpose, the finite element method with Ansys mechanical APDL program is used to solve the governing equations. Displacement, elastic and plastic strains, Von-Mises stress, energy densities, and contact pressure are evaluated during the impact of the particle. Additionally, it is found that the initial impact velocity has a significant effect on splat behavior. This mechanical model gives a promise results that can be improved to help understand the impact and flattening phenomenon.

  2. Dynamic characteristics of pulsed supersonic fuel sprays

    NASA Astrophysics Data System (ADS)

    Pianthong, K.; Matthujak, A.; Takayama, K.; Milton, B. E.; Behnia, M.

    2008-06-01

    This paper describes the dynamic characteristics of pulsed, supersonic liquid fuel sprays or jets injected into ambient air. Simple, single hole nozzles were employed with the nozzle sac geometries being varied. Different fuel types, diesel fuel, bio-diesel, kerosene, and gasoline were used to determine the effects of fuel properties on the spray characteristics. A vertical two-stage light gas gun was employed as a projectile launcher to provide a high velocity impact to produce the liquid jet. The injection pressure was around 0.88-1.24 GPa in all cases. The pulsed, supersonic fuel sprays were visualized by using a high-speed video camera and shadowgraph method. The spray tip penetration and velocity attenuation and other characteristics were examined and are described here. An instantaneous spray tip velocity of 1,542 m/s (Mach number 4.52) was obtained. However, this spray tip velocity can be sustained for only a very short period (a few microseconds). It then attenuates very quickly. The phenomenon of multiple high frequency spray pulses generated by a single shot impact and the changed in the angle of the shock structure during the spray flight, which had already been observed in previous studies, is again noted. Multiple shock waves from the conical nozzle spray were also clearly captured.

  3. Characterization of the pyrolysis products of methiopropamine.

    PubMed

    Bouso, Emily D; Gardner, Elizabeth A; O'Brien, John E; Talbot, Brian; Kavanagh, Pierce V

    2014-01-01

    1-(Thien-2-yl)-2-methylaminopropane (methiopropamine, MPA), appeared as a 'legal high' in late 2010. It is structurally similar to methamphetamine, with a thiophene ring replacing the benzene moiety. Methiopropamine reportedly retains the pharmacological properties of amphetamine stimulants, but it does not fall under existing drug laws in the USA and Ireland. The objective of this research was to identify the pyrolysis products formed under conditions that mimic those used by recreational drugs users. Thirteen pyrolysis products were identified and ten were confirmed by comparison to synthesized standards. Methods for synthesizing the standards as well as an alternative method for the synthesis of methiopropamine were developed. The MPA pyrolysis products are formed through N-dealkylation, N-alkylation, N-formylation, β-carbon oxidation, β-carbon oxidation/N-alkylation, amine elimination and carbon-carbon bond cleavage. Two pyrazine isomers also formed. Some of these products have the potential to be psychoactive while others are potentially toxic. PMID:24166818

  4. Coal pyrolysis in a rotary kiln: Part 1. Model of the pyrolysis of a single grain

    SciTech Connect

    Patisson, F.; Lebas, E.; Hanrot, F.; Ablitzer, D.; Houzelot, J.L.

    2000-04-01

    A mathematical model is presented which describes the pyrolysis of a single grain of coal and is designed to be incorporated into an overall model simulating the rotary kiln coal pyrolysis process. The grain model takes into account the principal physical phenomena occurring during the conversion of coal to coke, namely, heat transfer toward and within the grain, drying of the coal, and the evolution of volatile species. Particular care has been taken in the determination of the thermophysical and kinetic parameters necessary for the model. Thus, the drying kinetics for Lorraine coal were measured by thermogravimetry. The kinetics of pyrolysis were determined by both thermogravimetry and gas-phase chromatography, in order to separately monitor the evolution of the nine gaseous species considered. The true specific heat and the thermal conductivity of the solid were also measured as a function of temperature. The numerical model, based on the finite-volume method, calculates the temperature, composition, and mass flow rates for the different gases evolved at each point in the grain at any instant of time. The model was, finally, validated by comparing the calculated and measured values of the overall conversion of the pyrolysis reaction and the temperature at the center of the grain.

  5. Coal pyrolysis in a rotary kiln: Part I. Model of the pyrolysis of a single grain

    NASA Astrophysics Data System (ADS)

    Patisson, Fabrice; Lebas, Etienne; Hanrot, François; Ablitzer, Denis; Houzelot, Jean-Leon

    2000-04-01

    A mathematical model is presented which describes the pyrolysis of a single grain of coal and is designed to be incorporated into an overall model simulating the rotary kiln coal pyrolysis process. The grain model takes into account the principal physical phenomena occurring during the conversion of coal to coke, namely, heat transfer toward and within the grain, drying of the coal, and the evolution of volatile species. Particular care has been taken in the determination of the thermophysical and kinetic parameters necessary for the model. Thus, the drying kinetics for Lorraine coal were measured by thermogravimetry. The kinetics of pyrolysis were determined by both thermogravimetry and gasphase chromatography, in order to separately monitor the evolution of the nine gaseous species considered. The true specific heat and the thermal conductivity of the solid were also measured as a function of temperature. The numerical model, based on the finite-volume method, calculates the temperature, composition, and mass flow rates for the different gases evolved at each point in the grain at any instant of time. The model was, finally, validated by comparing the calculated and measured values of the overall conversion of the pyrolysis reaction and the temperature at the center of the grain.

  6. Concentration-response data on toxicity of pyrolysis gases from some natural and synthetic polymers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Huttlinger, N. V.

    1978-01-01

    Concentration-response data are presented on the toxic effects of the pyrolysis gases from some natural and synthetic polymers, using the toxicity screening test method developed at the University of San Francisco. The pyrolysis gases from wool, red oak, Douglas fir, polycaprolactam, polyether sulfone, polyaryl sulfone, and polyphenylene sulfide appeared to exhibit the concentration-response relationships commonly encountered in toxicology. Carbon monoxide seemed to be an important toxicant in the pyrolysis gases from red oak, Douglas fir, and polycaprolactam, but did not appear to have been the principal toxicant in the pyrolysis gases from polyether sulfone and polyphenylene sulfide.

  7. Effect of pyrolysis temperature on toxicity of gases from a polyethylene polymer

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Kosola, K. L.

    1978-01-01

    A polyethylene polymer was evaluated for time of toxic effect to occur as the result of exposure to gases generated by pyrolysis at various temperatures, using the toxicity screening test method developed at the University of San Francisco. Times to various animal responses decreased with increasing pyrolysis temperature over the range from 400 C to 800 C. Responses at a pyrolysis temperature of 350 C were more rapid than would be expected from the other data, and may indicate the predominance of different pyrolysis reactions in this particular temperature region.

  8. Pyrolysis and dehalogenation of plastics from waste electrical and electronic equipment (WEEE): a review.

    PubMed

    Yang, Xiaoning; Sun, Lushi; Xiang, Jun; Hu, Song; Su, Sheng

    2013-02-01

    Plastics from waste electrical and electronic equipment (WEEE) have been an important environmental problem because these plastics commonly contain toxic halogenated flame retardants which may cause serious environmental pollution, especially the formation of carcinogenic substances polybrominated dibenzo dioxins/furans (PBDD/Fs), during treat process of these plastics. Pyrolysis has been proposed as a viable processing route for recycling the organic compounds in WEEE plastics into fuels and chemical feedstock. However, dehalogenation procedures are also necessary during treat process, because the oils collected in single pyrolysis process may contain numerous halogenated organic compounds, which would detrimentally impact the reuse of these pyrolysis oils. Currently, dehalogenation has become a significant topic in recycling of WEEE plastics by pyrolysis. In order to fulfill the better resource utilization of the WEEE plastics, the compositions, characteristics and dehalogenation methods during the pyrolysis recycling process of WEEE plastics were reviewed in this paper. Dehalogenation and the decomposition or pyrolysis of WEEE plastics can be carried out simultaneously or successively. It could be 'dehalogenating prior to pyrolysing plastics', 'performing dehalogenation and pyrolysis at the same time' or 'pyrolysing plastics first then upgrading pyrolysis oils'. The first strategy essentially is the two-stage pyrolysis with the release of halogen hydrides at low pyrolysis temperature region which is separate from the decomposition of polymer matrixes, thus obtaining halogenated free oil products. The second strategy is the most common method. Zeolite or other type of catalyst can be used in the pyrolysis process for removing organohalogens. The third strategy separate pyrolysis and dehalogenation of WEEE plastics, which can, to some degree, avoid the problem of oil value decline due to the use of catalyst, but obviously, this strategy may increase the cost of whole recycling process. PMID:22951495

  9. Off-line pyrolysis and compound-specific stable carbon isotope analysis of lignin moieties: a new method for determining the fate of lignin residues in soil.

    PubMed

    Dungait, Jennifer A J; Stear, Natalie A; van Dongen, Bart E; Bol, Roland; Evershed, Richard P

    2008-06-01

    Off-line pyrolysis was used to liberate lignin moieties from dung and soil and, after trimethylsilylation, the delta(13)C values of these derivatives were determined by gas chromatography-combustion-isotope ratio mass spectrometry. Initial delta(13)C values determined for 4-vinylphenol, syringol, 4-vinylguaiacol, 4-acetylsyringol, 4-vinylsyringol, 4-(2-Z-propenyl)syringol, 4-(2-E-propenyl)syringol and 4-(2-propenone)syringol pyrolysis products of the lignin polyphenol structure from C(4) (delta(13)C(bulk) = -12.6%) and C(3) (delta(13)C(bulk) = -30.1 per thousand) dung confirmed the robust and reproducible nature of the off-line preparation technique. C(4) dung was used as a treatment in a randomised field experiment to assess the short-term sequestration of dung carbon in managed grasslands. Since lignin was on average 3.5 per thousand depleted in (13)C compared with bulk dung delta(13)C values, this may have resulted in an under-estimation of dung C incorporation based on bulk delta(13)C values. Therefore, an investigation of the compound-specific delta(13)C values of dung-derived lignin moieties extracted from soils sampled up to 372 days was undertaken. Delta(13)C values between lignin moieties extracted from treated and untreated soils showed that dung-derived lignin was not especially resistant to degradation and suggested that individual moieties of the lignin macromolecule must: (i) move into soil, (ii) be degraded, or (iii) be transformed diagenetically at different rates. This adds to a gathering body of evidence that lignin is not particularly stable in soils, which has considerable significance for the perceived role of different biochemical components in the cycling of C in soils. PMID:18446763

  10. Nasal corticosteroid sprays

    MedlinePLUS

    ... a corticosteroid spray at the beginning of pollen season will give you the best results in terms of decreasing symptoms during that season. Several brands of nasal corticosteroid spray are available. ...

  11. Spatial distribution visualization of PWM continuous variable-rate spray

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical application is a dynamic spatial distribution process, during which spray liquid covers the targets with certain thickness and uniformity. Therefore, it is important to study the 2-D and 3-D (dimensional) spray distribution to evaluate spraying quality. The curve-surface generation methods ...

  12. Remotely controlled spray gun

    NASA Technical Reports Server (NTRS)

    Cunningham, William C. (Inventor)

    1987-01-01

    A remotely controlled spray gun is described in which a nozzle and orifice plate are held in precise axial alignment by an alignment member, which in turn is held in alignment with the general outlet of the spray gun by insert. By this arrangement, the precise repeatability of spray patterns is insured.

  13. Azelastine Nasal Spray

    MedlinePLUS

    ... and replace with the pump unit. Prime the delivery system (pump unit) with four sprays or until a fine mist appears. If 3 days or more have elapsed since your last use of the nasal spray, reprime the pump with two sprays or until a fine mist appears.

  14. A Study on the Deposition of Al2O3 Coatings on Polymer Substrates by a Plasma Spray/Micro-Arc Oxidation Two-Step Method

    NASA Astrophysics Data System (ADS)

    Sun, Guanhong; He, Xiaodong; Jiang, Jiuxing; Sun, Yue; Zhong, Yesheng

    2013-02-01

    To increase the wear resistance of polymer matrix composites, alumina coatings were deposited on polymer substrates by a two-step method combining plasma spraying and micro-arc oxidation. The microstructures and phase compositions of the processed coatings were investigated for different treatment times. Uniformly distributed pores were found in addition to the presence of various coral-like structures and floccules on the surface of the coatings. The presence of α-Al2O3 and γ-Al2O3 phases was identified by XRD. The distribution of alumina was analyzed by EDS and is discussed. The maximum bond strength of the coatings was found to be 5.89 MPa. There was little thermal damage in the polymer substrates after the coatings were produced.

  15. Plasma Pyrolysis Assembly Regeneration Evaluation

    NASA Technical Reports Server (NTRS)

    Medlen, Amber; Abney, Morgan B.; Miller, Lee A.

    2011-01-01

    In April 2010 the Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS). This technology requires hydrogen to recover oxygen from carbon dioxide. This results in the production of water and methane. Water is electrolyzed to provide oxygen to the crew. Methane is vented to space resulting in a loss of valuable hydrogen and unreduced carbon dioxide. This is not critical for ISS because of the water resupply from Earth. However, in order to have enough oxygen for long-term missions, it will be necessary to recover the hydrogen to maximize oxygen recovery. Thus, the Plasma Pyrolysis Assembly (PPA) was designed to recover hydrogen from methane. During operation, the PPA produces small amounts of carbon that can ultimately reduce performance by forming on the walls and windows of the reactor chamber. The carbon must be removed, although mechanical methods are highly inefficient, thus chemical methods are of greater interest. The purpose of this effort was to determine the feasibility of chemically removing the carbon from the walls and windows of a PPA reactor using a pure carbon dioxide stream.

  16. Method of creating starch-like ultra-fine rice flour and effect of spray drying on formation of free fatty acid.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice flour from long, medium, and short grain cultivars were processed by passing a 32% rice flour slurry through a microfluidizer at 100 MPa, and spray dryer at three different outlet temperatures, OT (50C, 80C, and 115C). Spray drying conditions were controlled by the flow-rate of the slurry ...

  17. Characterization of sprays

    NASA Technical Reports Server (NTRS)

    Chigier, N.; Mao, C.-P.

    1984-01-01

    It is pointed out that most practical power generation and propulsion systems involve the burning of different types of fuel sprays, taking into account aircraft propulsion, industrial furnaces, boilers, gas turbines, and diesel engines. There has been a lack of data which can serve as a basis for spray model development and validation. A major aim of the present investigation is to fill this gap. Experimental apparatus and techniques for studying the characteristics of fuel sprays are discussed, taking into account two-dimensional still photography, cinematography, holography, a laser diffraction particle sizer, and a laser anemometer. The considered instruments were used in a number of experiments, taking into account three different types of fuel spray. Attention is given to liquid fuel sprays, high pressure pulsed diesel sprays, and coal-water slurry sprays.

  18. Low-temperature growth and physical investigations of undoped and (In, Co) doped ZnO thin films sprayed on PEI flexible substrate

    NASA Astrophysics Data System (ADS)

    Ben Ameur, S.; Barhoumi, A.; Mimouni, R.; Amlouk, M.; Guermazi, H.

    2015-08-01

    ZnO thin films were deposited on polymer substrate Polyethyerimide (PEI) at 250 °C by spray pyrolysis technique. The effects of different doping elements (Co and In) on physical properties of ZnO thin films were investigated. Thin film characterizations were carried out using X-ray diffraction technique, UV-Vis-NIR spectroscopy, Photoluminescence (PL) spectroscopy and the contact angle measurement method. XRD measurement showed a successful growth of crystalline films on polymer substrate at low temperature by the spray pyrolysis process. XRD patterns revealed that all films consist of single ZnO phase and were well crystallized with preferential orientation towards (1 0 1) direction. Doping by cobalt has effective role in the enhancement of the crystalline quality, increases in the band gap according to Burstein Moss effect. Doping with indium leads rather to the decrease of both crystallinity and optical band gap energy value. Photoluminescence of the films showed UV emission (NBE) and visible emission related to defects. The contact angles were measured to study the effect of various doping elements on the hydrophobicity of the film depending on surface roughness. Results showed strong dependence on the doping element. In fact, doping with cobalt element increases the roughness of ZnO films and reinforces the surface from hydrophilic to hydrophobic (θ > 90°).

  19. A fluorescent imaging technique for quantifying spray deposits on plant leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of the unique characteristics of electrostatically-charged sprays, use of traditional methods to quantify deposition from these sprays has been challenging. A new fluorescent imaging technique was developed to quantify spray deposits from electrostatically-charged sprays on natural plant lea...

  20. The pyrolysis process of sewage sludge

    NASA Astrophysics Data System (ADS)

    Kosov, V. F.; Umnova, O. M.; Zaichenko, V. M.

    2015-11-01

    The experimental investigations of pyrolysis process sewage sludge at different conditions are presented. As a result of executed investigations it was shown that syngas (mixrure of CO and H2) used in gas engine can be obtained in pyrolysis process.

  1. Pyrolysis kinetics of lignocellulosic materials

    SciTech Connect

    Balci, S.; Dogu, T.; Yuecel, H. . Dept. of Chemical Engineering)

    1993-11-01

    Pyrolysis kinetics of almond and hazelnut shells and beech wood were carried out using a thermogravimetric technique. Experiments were repeated for different final pyrolysis temperatures ranging from 300 to 850 C. Approximately 90% of the pyrolysis reactions were completed up to 450 C. The initial values of the activation energy of pyrolysis reaction were found to be around 22 kcal/mol for shells of almond and hazelnut. On the other hand, initial activation energy of beech wood pyrolysis was found as 29.4 kcal/mol. Results indicated that a first-order decomposition in terms of volatile content of the reactant showed good agreement with the data only at the initial stages of the reaction. The reaction rate constant was found to decrease with reaction extent due to the changes in the chemical and physical structure of the solid. Among several models proposed, a model which predicted an increase of activation energy with reaction extent gave the best agreement with the experimental data.

  2. Pyrolysis-GC-MS Analysis of Antarctic Lake Sediments

    NASA Astrophysics Data System (ADS)

    Steininger, H.; Goetz, W.

    2012-03-01

    Antarctic lake sediments were analyzed with Pyrolysis-GC-MS, a method similar to the methods used on board MSL and Exomars. This is the starting point to build a library of data from terrestrial samples to improve the analysis of martian samples.

  3. Experimental research on spray and combustion characteristics of the third generation conical spray

    NASA Astrophysics Data System (ADS)

    Li-Yan, Feng; Wu-Qiang, Long; Bao-Guo, Du; Hua, Tian; Tomio, Obokata

    2005-03-01

    A new generation conical spray system for conventional diesel engines or premixed combustion diesel engines is introduced. By means of oriented impingement method, flexible spray penetration in design is realized. High-speed photograph was used to investigate the spatial distribution characteristics of the new spray for cases of different impingement angles and needle valve opening pressures. The results show that, by applying spray impingement orientation, fuel jets spread along the cone surface as shape of sectors, so the dispersion of jets is increased obviously. Changing on impingement angle leads to variation of penetration, which is critical in homogeneous mixture preparation. Due to the flexibility of spray penetration in design, the spray impingement on liner is avoided in a great extent. The results also indicate that higher needle valve opening pressure results in longer penetration and larger spray angle after impingement. Combustion characteristics of the impinged conical spray were studied in the 1135 type diesel engine. The new impinged conical spray system work smoothly in full load range with better fuel economy and lower emissions of NO x and soot than the original test engine.

  4. Effect of Spray Parameters on the Corrosion Behavior of HVOF Sprayed WC-Co-Cr Coatings

    NASA Astrophysics Data System (ADS)

    Hong, Sheng; Wu, Yuping; Zheng, Yugui; Wang, Bo; Gao, Wenwen; Li, Gaiye; Ying, Guobing; Lin, Jinran

    2014-04-01

    WC-10Co-4Cr cermet coatings were deposited on the substrate of AISI 1045 steel by using high-velocity oxygen-fuel (HVOF) thermal spraying process. The Taguchi method including the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) was employed to optimize the porosity and, in turn, the corrosion resistance of the coatings. The spray parameters evaluated in this study were spray distance, oxygen flow, and kerosene flow. The results indicated that the important sequence of spray parameters on the porosity of the coatings was spray distance > oxygen flow > kerosene flow, and the spray distance was the only significant factor. The optimum spraying condition was 300 mm for the spray distance, 1900 scfh for the oxygen flow, and 6.0 gph for the kerosene flow. The results showed the significant influence of the microstructure on the corrosion resistance of the coatings. Potentiodynamic polarization and electrochemical impendence spectroscopy (EIS) results showed that the WC-10Co-4Cr cermet coating obtained by the optimum spraying condition with the lowest porosity exhibits the best corrosion resistance and seems to be an alternative to hard chromium coating.

  5. Comprehensive utilization of the pyrolysis products from sewage sludge.

    PubMed

    Xu, W Y; Wu, D

    2015-01-01

    Bio-oils were produced from pyrolysis of sewage sludge in a horizontal tubular furnace under the anoxic or anaerobic conditions, by varying operating parameters and moisture content (MC) of the feedstock. Physicochemical properties of the obtained bio-oil (such as density, acid value, kinematical viscosity, high heating value and flash point) were analysed and compared with Chinese fuel standards. Tend, RT and ? were found critical to control the yield and physico-chemical properties of bio-oil products. The relative importance of various parameters such as Tend, RT, ? and MC was determined and the optimum values for the lowest kinematic viscosity and acid value and the highest yield of the bio-oil were achieved using the orthogonal matrix method. The parameters 550C, 45?min, 5C?min(-1) and MC of 10% were found effective in producing the bio-oils with most of the desirable physico-chemical properties and yield. Benefit analysis was conducted to further optimize the operating parameters, considering pyrolysis treatment, comprehensive utilization of the pyrolysis products and final disposal of sewage sludge; the results showed the best economy of the pyrolysis parameters 450C, 75?min, 3C?min(-1) and MC of 10%. The char obtained under this condition may serve as a microporous liquid adsorbent, while the bio-oil may serve as a low grade fuel oil after upgrading it with conventional fuel oil and deacidification. Pyrolysis products may become economically competitive in addition to being environment friendly. PMID:25609547

  6. Experimental Research of Pyrolysis Gases Cracking on Surface of Charcoal

    NASA Astrophysics Data System (ADS)

    Kosov, Valentin; Kosov, Vladimir; Zaichenko, Victor

    For several years, in the Joint Institute for High Temperatures of Russian Academy of Sciences, two-stage technology of biomass processing has been developing [1]. The technology is based on pyrolysis of biomass as the first stage. The second stage is high-temperature conversion of liquid fraction of the pyrolysis on the surface of porous charcoal matrix. Synthesis gas consisted of carbon monoxide and hydrogen is the main products of the technology. This gas is proposed to be used as fuel for gas-engine power plant. For practical implementation of the technology it is important to know the size of hot char filter for full cracking of the pyrolysis gases on the surface of charcoal. Theoretical determination of the cracking parameters of the pyrolysis gases on the surface of coal is extremely difficult because the pyrolysis gases include tars, whose composition and structure is complicated and depends on the type of initial biomass. It is also necessary to know the surface area of the char used in the filter, which is also a difficult task. Experimental determination of the hot char filter parameters is presented. It is shown that proposed experimental method can be used for different types of biomass.

  7. Plasma-Sprayed Coatings on Porous Surfaces

    NASA Technical Reports Server (NTRS)

    Leibert, C. H.

    1986-01-01

    Need for combining benefits of duplex thermal-barrier coatings with film cooling on gas-turbine vanes and blades stimulated development of improved method for plasma spraying these coatings. Method reduces blocking of holes by plasma-sprayed material and at same time reduces base-metal oxidation during coating operation. Features provide potential for increased engine efficiency and power, reduced fuel consumption, use of less costly materials or construction procedures, and extended life and durability.

  8. Toxicity of pyrolysis gases from wood

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Huttlinger, N. V.; Oneill, B. A.; Kourtides, D. A.; Parker, J. A.

    1977-01-01

    The toxicity of the pyrolysis gases from nine wood samples was investigated. The samples of hardwoods were aspen poplar, beech, yellow birch, and red oak. The samples of softwoods were western red cedar, Douglas fir, western hemlock, eastern white pine, and southern yellow pine. There was no significant difference between the wood samples under rising temperature conditions, which are intended to simulate a developing fire, or under fixed temperature conditions, which are intended to simulate a fully developed fire. This test method is used to determine whether a material is significantly more toxic than wood under the preflashover conditions of a developing fire.

  9. Investigation of structural, optical, electrical and dielectric properties of catalytic sprayed hausmannite thin film

    SciTech Connect

    Larbi, T.; Ouni, B.; Boukhachem, A.; Boubaker, K. Amlouk, M.

    2014-12-15

    Hausmannite Mn{sub 3}O{sub 4} thin film have been synthesized using spray pyrolysis method. These films are characterized using X-ray diffraction (XRD), atomic force microscope AFM, UVvisNIR spectroscopy and impedance spectroscopy. XRD study confirms the tetragonal structure of the as-deposited films with lattice parameters, a = 5.1822 and c = 9.4563 and a grain size of about 56 nm. UVvisNIR spectroscopy was further used to estimate optical constants such as extinction coefficient, refractive index, band gap and Urbach energy. Moreover, impedance spectroscopy analysis was employed to estimate electrical and dielectrical properties of the sprayed thin films. The activation energy values deduced from DC conductivity and relaxation frequency were almost the same, revealing that the transport phenomena is thermally activated by hopping between localized states. The AC conductivity is found to be proportional to ?{sup s}. The temperature dependence of the AC conductivity and the frequency exponent, s was reasonably well interpreted in terms of the correlated barrier-hopping CBH model. The dielectric properties were sensitive to temperature and frequency. The study of the electrical modulus indicated that the charge carrier was localized. Experimental results concerning optical constants as Urbach energy, dielectric constant, electric modulus and AC and DC conductivity were discussed in terms of the hopping model as suggested by Elliott.

  10. An optically accessible pyrolysis microreactor

    NASA Astrophysics Data System (ADS)

    Baraban, J. H.; David, D. E.; Ellison, G. Barney; Daily, J. W.

    2016-01-01

    We report an optically accessible pyrolysis micro-reactor suitable for in situ laser spectroscopic measurements. A radiative heating design allows for completely unobstructed views of the micro-reactor along two axes. The maximum temperature demonstrated here is only 1300 K (as opposed to 1700 K for the usual SiC micro-reactor) because of the melting point of fused silica, but alternative transparent materials will allow for higher temperatures. Laser induced fluorescence measurements on nitric oxide are presented as a proof of principle for spectroscopic characterization of pyrolysis conditions.

  11. Bear Spray Safety Program

    USGS Publications Warehouse

    Blome, C.D.; Kuzniar, R.L.

    2009-01-01

    A bear spray safety program for the U.S. Geological Survey (USGS) was officially initiated by the Firearms Safety Committee to address accident prevention and to promote personnel training in bear spray and its transportation, storage, and use for defense against wild animals. Used as part of a system including firearms, or used alone for those who choose not to carry a firearm, bear spray is recognized as an effective tool that can prevent injury in a wild animal attack.

  12. Pyrolysis kinetics of hazelnut husk using thermogravimetric analysis.

    PubMed

    Ceylan, Selim; Topu, Y?ld?ray

    2014-03-01

    This study aims at investigating physicochemical properties and pyrolysis kinetics of hazelnut husk, an abundant agricultural waste in Turkey. The physicochemical properties were determined by bomb calorimeter, elemental analysis and FT-IR spectroscopy. Physicochemical analysis results showed that hazelnut husk has a high calorimetric value and high volatile matter content. Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20C/min). Three different kinetic models, the iso-conversional Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) models and Coats-Redfern method were applied on TGA data of hazelnut husk to calculate the kinetic parameters including activation energy, pre-exponential factor and reaction order. Simulation of hazelnut husk pyrolysis using data obtained from TGA analysis showed good agreement with experimental data. Combining with physicochemical properties, it was concluded that this biomass can become useful source of energy or chemicals. PMID:24508656

  13. Adhesion Strength of Thermal Barrier Coatings with Thermal-Sprayed Bondcoat Treated by Compound Method of High-Current Pulsed Electron Beam and Grit Blasting

    NASA Astrophysics Data System (ADS)

    Cai, Jie; Guan, Qingfeng; Lv, Peng; Hou, Xiuli; Wang, Zhiping; Han, Zhiyong

    2015-06-01

    Microstructural characteristics and adhesion properties of air plasma spraying, thermal barrier coatings (TBCs) having thermally sprayed bond coats treated by high-current pulsed electron beam (HCPEB) irradiation, and a combination treatment of HCPEB and grit blasting were investigated. Microstructure observations revealed that the original coarse surface of thermally sprayed bond coat was significantly changed to interconnected bulged nodules with a compact appearance after HCPEB irradiation. With further grit blasting treatment, these series of bulged nodules appeared with successive and uniform jagged edges. Surface roughness of the bond coat after compound treatment became higher due to these bulged nodules with jagged edges, which was conducive to ceramic deposition. The results of the tensile test revealed that the adhesion strength of thermally sprayed TBCs with the bond coats conducted by a compound treatment was obviously increased. The combination treatment of HCPEB and grit blasting improved the interfacial bonding strength as well as the interfacial homogeneity.

  14. Concentration-response data on toxicity of pyrolysis gases from six synthetic polymers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Huttlinger, N. V.

    1978-01-01

    Concentration-response data are presented on the toxic effects of the pyrolysis gases from six synthetic polymers on Swiss Webster male mice, using a toxicity screening test method. The polymers consisted of one sample each of polycarbonate and polystyrene, and two samples each of polyethylene and acrylonitrile-butadiene-styrene (ABS). All six samples were evaluated using the rising temperature program, and three samples were evaluated using the fixed temperature program. The pyrolysis gases from polycarbonate, polyethylene, and ABS appeared to exhibit the concentration-response relationships commonly encountered in toxicology. The polystyrene sample gave variable results; probably due to poor reproducibility of the essentially anaerobic pyrolysis. Carbon monoxide seemed to be the principal toxicant in the pyrolysis gases from polycarbonate and polyethylene, but did not appear to be the principal toxicant in the pyrolysis gases from ABS.

  15. A Comparative study of microwave-induced pyrolysis of lignocellulosic and algal biomass.

    PubMed

    Wang, Nan; Tahmasebi, Arash; Yu, Jianglong; Xu, Jing; Huang, Feng; Mamaeva, Alisa

    2015-08-01

    Microwave (MW) pyrolysis of algal and lignocellulosic biomass samples were studied using a modified domestic oven. The pyrolysis temperature was recorded continuously by inserting a thermocouple into the samples. Temperatures as high as 1170 and 1015C were achieved for peanut shell and Chlorella vulgaris. The activation energy for MW pyrolysis was calculated by Coats-Redfern method and the values were 221.96 and 214.27kJ/mol for peanut shell and C. vulgaris, respectively. Bio-oil yields reached to 27.7wt.% and 11.0wt.% during pyrolysis of C. vulgaris and peanut shell, respectively. The bio-oil samples from pyrolysis were analyzed by a gas chromatography-mass spectrometry (GC-MS). Bio-oil from lignocellulosic biomass pyrolysis contained more phenolic compounds while that from microalgae pyrolysis contained more nitrogen-containing species. Fourier transform infrared spectroscopy (FTIR) analysis results showed that concentration of OH, CH, CO, OCH3, and CO functional groups in char samples decreased significantly after pyrolysis. PMID:25935388

  16. Effect of annealing time on the physical properties of ultrasonically sprayed CdS:In thin films

    NASA Astrophysics Data System (ADS)

    Karakaya, S.; Gencyılmaz, O.; Ozbas, O.

    2012-09-01

    In this work, CdS and In doped CdS films were prepared by ultrasonic spray pyrolysis (USP) technique and were annealed at 450 °C in an air atmoshpere. The optical constants (n and k) and thicknesses of the films were determined by spectroscopic ellipsometry. Transmission and absorbance spectra were taken by UV spectrophotometer. Optical method was used to determine the band gap value of the films. Atomic force microscope (AFM) images were taken to see the effect of annealing time on surface topography and roughness of the films. Electrical resistivities of the films were analyzed by four probe technique. As a result, the application potential of annealed CdS:In films for photovoltaic solar cells and optoelectronic applications were investigated.

  17. Fuel spray diagnostics

    NASA Technical Reports Server (NTRS)

    Bosque, M. A.

    1984-01-01

    Several laser measurement methods are being studied to provide the capability to make droplet size and velocity measurements under a variety of spray conditions. The droplet sizing interferometer (DSI) promises to be a successful technique because of its capability for rapid data acquisition, compilation and analysis. Its main advantage is the ability to obtain size and velocity measurements in air-fuel mixing studies and hot flows. The existing DSI at NASA Lewis is a two-color, two-component system. Two independent orthogonal measurements of size and velocity components can be made simultaneously. It also uses an off-axis large-angle light scatter detection. The fundamental features of the system are optics, signal processing and data management system. The major component includes a transmitter unit, two receiver units, two signal processors, two data management systems, two Bragg cell systems, two printer/plotters, a laser, power supply and color monitor.

  18. Planning robotic trajectories for thermal spray shape deposition

    NASA Astrophysics Data System (ADS)

    Fasching, M. M.; Prinz, F. B.; Weiss, L. E.

    1993-03-01

    Thermal spray shape deposition is a new process for fabricating net-shape parts by incremental material buildup of cross-sectional layers. This article presents an approach for spraying thin, flat layers using a robotic thermal spray system. Asymmetries of the spray distribution are first corrected by tilting the spray torch based on a computer model of the measured spray distribution. The path of the torch is then found using heuristics that are based on the estimated standard deviation of the corrected distribution. For example, thick arc-sprayed coatings of approximately 4.0 mm thickness have been deposited using this method, with the resulting standard deviation from the mean thickness ranging from 20.0 to 30.0 ?m. To demonstrate the shape deposition process, a prototype turbine blade shape was built using these optimized trajectories.

  19. LSPRAY-IV: A Lagrangian Spray Module

    NASA Technical Reports Server (NTRS)

    Raju, M. S.

    2012-01-01

    LSPRAY-IV is a Lagrangian spray solver developed for application with parallel computing and unstructured grids. It is designed to be massively parallel and could easily be coupled with any existing gas-phase flow and/or Monte Carlo Probability Density Function (PDF) solvers. The solver accommodates the use of an unstructured mesh with mixed elements of either triangular, quadrilateral, and/or tetrahedral type for the gas flow grid representation. It is mainly designed to predict the flow, thermal and transport properties of a rapidly vaporizing spray. Some important research areas covered as a part of the code development are: (1) the extension of combined CFD/scalar-Monte- Carlo-PDF method to spray modeling, (2) the multi-component liquid spray modeling, and (3) the assessment of various atomization models used in spray calculations. The current version contains the extension to the modeling of superheated sprays. The manual provides the user with an understanding of various models involved in the spray formulation, its code structure and solution algorithm, and various other issues related to parallelization and its coupling with other solvers.

  20. Initial Stages of Pyrolysis of Polyethylene

    NASA Astrophysics Data System (ADS)

    Popov, Konstantin V.

    Combustion and flammability of plastics are important topics of practical interest directly related to fire safety and recycling of polymeric materials; pyrolysis of the solid is the initial step of its combustion. One of the main ways to study such complicated processes is through detailed mechanistic modeling, in which the process is represented by a set of many elementary reactions. Mechanistic modeling of combustion of plastics is considerably hindered by the lack of necessary kinetic data. In virtually all existing models of polymer pyrolysis the majority of kinetic data used are derived from the corresponding gas phase values of smaller species. The use of gas phase rate constants is, generally, not justified without an experimental justification. In the first part of the work the influence of condensed phase on the rate of scission of a carbon-carbon bond (the reaction that initiates pyrolysis and combustion) in polyethylene (PE) was studied using the method of Reactive Molecular Dynamics (RMD). A method based on a two-step kinetic mechanism was developed to decouple the cage effect from the kinetics of the reaction under study. It was observed that under the conditions of condensed phase the rate constant of C-C bond scission in PE decreased by an order of magnitude compared to that obtained in vacuum. It was also shown that under the conditions of polymer melt the rate constant does not depend on the length of the polymer chain. In the second part of the work the kinetics of liquid phase and gas phase products of PE pyrolysis were studied experimentally using Gas Chromatography and Nuclear Magnetic Resonance. Based on the assumption of applicability of gas phase kinetic data for C-C scission reaction and beta-scission reaction under the conditions of polymer melt, rate constants of hydrogen transfer, radical addition to double bonds, and radical recombination were determined via kinetic modeling of the experimental results. The obtained values of the rate constants were found to be in reasonable agreement with the constants of similar reactions of smaller molecules in the gas phase.

  1. Investigation of particulate formation during diesel spray combustion: CARS for diesel spray combustion. Final technical report

    SciTech Connect

    Boedeker, L.R.

    1991-09-01

    An experimental and analytical research program has been carried out whose objectives were to investigate strategies for using coherent anti-Stokes Raman spectroscopy (CARS) laser diagnostic techniques for detecting the vapor phase of liquid fuel sprays, determining fuel-air ratio and the degree of fuel pyrolysis. The extent to which CARS can provide valid vapor phase fuel measurements in the presence of droplets within the CARS resolution volume will determine its ultimate utility for engine measurements. Hence, the priority in this program was maintained toward investigating possible adverse droplet effects on CARS measurements. Droplets in a relevant size range (25-- 50 microns) were generated for convenience with a spray nozzle. Tests were conducted in a spray chamber at 1 atm pressure under near- saturated fuel vapor pressure conditions, with and without a toluene fuel spray turned on. For reasons of safety an inert gas, CO{sub 2}, was used to simulate O{sub 2}. It was necessary to provide reliable vapor phase CARS reference spectra for these spray studies in order to insure that spurious liquid effects were not present and known vapor phase spectra were attained. To provide these reference spectra the capability was developed of isolating, in a CARS test cell, the vapor phase of fuels that are normally liquids at room temperature and pressure. The cell could be evacuated with a vacuum pump and heated uniformly up to about 100 C. Hence, a capability was established to measure nonresonant and resonant vapor phase CARS features of normally liquid fuels over wide pressure and temperature range, needed for evaluating CARS fuel-air analysis strategies.

  2. Vacuum pyrolysis of used tires

    SciTech Connect

    Roy, C.; Darmstadt, H.; Benallal, B.; Chaala, A.; Schwerdtfeger, A.E.

    1995-11-01

    The vacuum pyrolysis of used tires enables the recovery of useful products, such as pyrolytic oil and pyrolytic carbon black (CB{sub P}). The light part of the pyrolytic oil contains dl-limonene which has a high price on the market. The naphtha fraction can be used as a high octane number component for gasoline. The middle distillate demonstrated mechanical and lubricating properties similar to those of the commercial aromatic oil Dutrex R 729. The heavy oil was tested as a feedstock for the production of needle coke. It was found that the surface morphology of CB{sub P} produced by vacuum pyrolysis resembles that of commercial carbon black. The CB{sub P} contains a higher concentration of inorganic compounds (especially ZnO and S) than commercial carbon black. The pyrolysis process feasibility looks promising. One old tire can generate upon vacuum pyrolysis, incomes of at least $2.25 US with a potential of up to $4.83 US/tire upon further product improvement. The process has been licensed to McDermott Marketing Servicing Inc. (Houston) for its exploitation in the US.

  3. Autothermal pyrolysis of waste tires

    SciTech Connect

    Wey, M.Y.; Liou, B.H.; Wu, S.Y.; Zhang, C.H.

    1995-11-01

    The main objective of this research was to study the operating parameters of autothermal pyrolysis of scrap tires in a laboratory-scale fluidized bed reactor with a 100-cm bed height (10 cm I.D.) and a 100-cm freeboard (25 cm I.D.). Scrap tires were pyrolyzed in a limited oxygen supply, so that the heat for pyrolysis of the scrap tires was provided by combustion of some portion of the scrap tires. The operating parameters evaluated included the effect on the pyrolysis oil products and their relative proportions of (1) the air factor (0.07-0.035); (2) the pyrolysis temperature (370-570{degree}C); and (3) the catalyst added (zeolite and calcium carbonate). The results show that: (1) the composition of the liquid hydrocarbon obtained is affected significantly by the air factor; (2) the higher operating temperature caused a higher yield of gasoline and diesel; (3) the yield of gasoline increased due to the catalyst zeolite added, and the yield of diesel increased due to the addition of the catalyst calcium carbonate; (4) the principal constituents of gasoline included dipentene and diprene. 30 refs., 10 figs., 5 tabs.

  4. Comparison between the discrete and finite element methods for modelling an agricultural spray boomPart 1: Theoretical derivation

    NASA Astrophysics Data System (ADS)

    Anthonis, J.; Ramon, H.

    2003-09-01

    The paper develops a systematic procedure for modelling linear flexible multibody structures of which the flexible parts are a composition of beams. The theory of mechanics of solids is fit into a general expression of virtual work, linking rigid-body motions with flexible deformations of the different bodies. A comparison is made with the finite element method for approximating the behaviour of the flexible bodies. It turns out that the discrete element method boils down to a particular selection of shape functions of which the mass matrix is inconsistent with the flexibility matrix. Furthermore, contrary to the finite element method, only point forces can be applied.

  5. Pyrolysis kinetics of waste PVC pipe.

    PubMed

    Kim, S

    2001-01-01

    The pyrolysis kinetics of waste PVC pipe was investigated with a thermal gravimetric analysis system at heating rates of 5, 10, and 30 degrees C/min in a nitrogen atmosphere. Freeman-Carroll method was employed to evaluate kinetic parameters. Two dominant peaks were observed on derivative gravimetric curves, hypothetically suggesting a two-stage apparent reaction model. The first-stage reaction was likely to be represented by stoichiometric reaction to yield volatiles (mainly HCl) and intermediates. The second-stage reaction might be described by thermal degradation of intermediates competitively into gas, liquid, and solid by-products. Quasi-isothermal operations were introduced to verify the reaction types of the first and second reaction. The generation reaction of intermediates achieved at lower temperatures was carried out independently with their decomposition reaction at higher temperatures. The effects of additives on the pyrolysis kinetics of waste PVC pipe seem to be significant, especially on the first-stage reaction. The first-stage reaction was retarded. A merged peak at low temperatures was observed on the derivative thermogravimetry (DTG) curve instead of two peaks usually observed for that of pure PVC resin. The first peak on the DTG curve of pure PVC resin may shift more, resulting in the complete overlap of two peaks. The quantity of evolved HCl was likely to decrease because of interaction of metal components of stabilizers with either HCl or active chlorine atom or both. The final residual fraction increased as a result of pyrolysis of organic forms of additives to yield extra char. On the other hand, the second-stage reaction kinetics demonstrates a similar pattern to that of pure PVC resin, implying that the effects of additives may be less significant in comparison with that at the first-stage reaction. PMID:11530916

  6. Li EXCESS Li4+xTi5-xO12-?/C COMPOSITE USING SPRAY-DRYING METHOD AND ITS ELECTRODE PROPERTIES

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Daisuke; Suzuki, Norio; Kadoma, Yoshihiro; Ui, Koichi; Kumagai, Naoaki

    2012-03-01

    We have prepared a lithium excess carbon composite material, Li4+xTi5-xO12-?/C (LTO/C), using various amounts of sucrose as a carbon source by the spray-drying method. The prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and elemental analysis. The prepared material had the Li4Ti5O12 phase including 3.9-18.4 wt.% carbon. Transmission electron microscopy images and the selected area diffraction (SAD) pattern showed that the prepared materials consisted of a carbon nanonetwork in the LTO/C composite. The charge-discharge cycling tests were carried out using the R2032 coin-type cell under the following conditions; 1.2-3.0 V, 0.1 C-10 C (1 C = 175 mA g-1), 25C. Based on the electrochemical results, the electrode performance of the prepared material was improved with increasing amounts of residual carbon, in particular, LTO/C including 6.2 wt.% residual carbon exhibited the best electrode performance of 156 mAh g-1 at 1 C during 50 cyclings when compared to the other materials.

  7. PLGA microspheres for the ocular delivery of a peptide drug, vancomycin using emulsification/spray-drying as the preparation method: in vitro/in vivo studies.

    PubMed

    Gavini, Elisabetta; Chetoni, Patrizia; Cossu, Massimo; Alvarez, Maria Gemma; Saettone, Marco Fabrizio; Giunchedi, Paolo

    2004-03-01

    The aim of this study was an in vitro/in vivo investigation on poly(lactide-co-glycolide) (PLGA) microspheres as carriers for the topical ocular delivery of a peptide drug vancomycin (VA). The microspheres were prepared by an emulsification/spray-drying technique that can be proposed as an alternative to the double emulsion method for preparation of peptide-loaded microparticles. The drug encapsulation efficiencies were close to the theoretical values (84.2-99.5%); the average particle size, expressed as dvs, was about 11 microm. The microspheres were able to modulate the in vitro drug release of VA with a behavior dependent on their composition: the highest drug content corresponded to the highest release rate. In vivo studies were carried out by assessing the pharmacokinetic profile of VA in the aqueous humor of rabbits after topical administration of aqueous suspensions of microspheres. High and prolonged VA concentrations and increased AUC values (2-fold) with respect to an aqueous solution of the drug were observed. Increasing the viscosity of the microsphere suspension by addition of a suspending-viscosizing agent (hydroxypropylcellulose) did not produce an increase of the ocular bioavailability. PLGA microspheres can be proposed as a system for ocular delivery of peptide drugs. PMID:15018976

  8. Substrate-Deposited Sea Spray Aerosol Particles: Influence of Analytical Method, Substrate, and Storage Conditions on Particle Size, Phase, and Morphology.

    PubMed

    Laskina, Olga; Morris, Holly S; Grandquist, Joshua R; Estillore, Armando D; Stone, Elizabeth A; Grassian, Vicki H; Tivanski, Alexei V

    2015-11-17

    Atmospheric aerosols are often collected on substrates and analyzed weeks or months after the initial collection. We investigated how the selection of substrate and microscopy method influence the measured size, phase, and morphology of sea spray aerosol (SSA) particles and how sample storage conditions affect individual particles using three common microscopy techniques: optical microscopy, atomic force microscopy, and scanning electron microscopy. Micro-Raman spectroscopy was used to determine changes in the water content of stored particles. The results show that microscopy techniques operating under ambient conditions provide the most relevant and robust measurement of particle size. Samples stored in a desiccator and at ambient conditions leads to similar sizes and morphologies, while storage that involves freezing and thawing leads to irreversible changes due to phase changes and water condensation. Typically, SSA particles are deposited wet and, if possible, samples used for single-particle analysis should be stored at or near conditions at which they were collected in order to avoid dehydration. However, if samples need to be dry, as is often the case, then this study found that storing SSA particles at ambient laboratory conditions (17-23% RH and 19-21 C) was effective at preserving them and reducing changes that would alter samples and subsequent data interpretation. PMID:26477686

  9. A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu.

    PubMed

    Muguli, Ganesh; Vadaparthi, P R Rao; Ramesh, B; Gowda, Vishakante; Paramesh, Rangesh; Jadhav, Atul N; Babu, K Suresh

    2015-05-01

    "Triphalaguggulu" is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn.) Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn.) Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of "Triphalaguggulu" preparation using gallic acid (for triphala), piperine (for P. longum L.) and guggulsterones (for guggulu) is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v) as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z) and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines. PMID:26109777

  10. A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu

    PubMed Central

    Muguli, Ganesh; Vadaparthi, P. R. Rao; Ramesh, B.; Gowda, Vishakante; Paramesh, Rangesh; Jadhav, Atul N.; Babu, K. Suresh

    2015-01-01

    “Triphalaguggulu” is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn.) Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn.) Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of “Triphalaguggulu” preparation using gallic acid (for triphala), piperine (for P. longum L.) and guggulsterones (for guggulu) is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v) as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z) and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines. PMID:26109777

  11. A novel direct spray-from-tissue ionization method for mass spectrometric analysis of human brain tumors.

    PubMed

    Kononikhin, Alexey; Zhvansky, Evgeny; Shurkhay, Vsevolod; Popov, Igor; Bormotov, Denis; Kostyukevich, Yury; Karchugina, Sofiia; Indeykina, Maria; Bugrova, Anna; Starodubtseva, Natalia; Potapov, Alexander; Nikolaev, Eugene

    2015-10-01

    Real-time feedback about dissected tissue during the neurosurgical procedure is strongly requested. A novel direct ionization mass spectrometric method for identifying pathological differences in tissues is proposed. The method is based on simultaneous extraction of tissue lipids and electrospray ionization which allows mass spectrometric data to be obtained directly from soft tissues. The advantage of this method is the stable flow of solvent, which leads to stable time-dependent spectra. The tissues included necrotized tissues and tumor tissues in different combinations. Capability for direct analysis of samples of dissected tissues during the neurosurgical procedure is demonstrated. Data validation is conducted by compound identification using precise masses from the MS profile, MS/MS, and isotopic distribution structure analysis. The method can be upgraded and applied for real-time identification of tissues during surgery. This paper describes the technique and its application perspective. For these purposes, other methods were compared with the investigated one and the results were shown to be reproducible. Differences in lipid profiles were observed even in tissues from one patient where distinctions between different samples could be poor. The paper presents a proof of concept for the method to be applied in neurosurgery particularly and in tissue analysis generically. The paper also contains preliminary results proving the possibility of observing differences in mass spectra of different tumors. PMID:26277186

  12. Cold spray nozzle design

    DOEpatents

    Haynes, Jeffrey D. (Stuart, FL); Sanders, Stuart A. (Palm Beach Gardens, FL)

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  13. SPRAY ATOMIZATION MODELS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop protection product labels are now being written with spray droplet spectra classification terms that have specific definitions. Some of these terms are the same as previously used for generic descriptions such as fine or coarse sprays, but these terms used on new product labels have very speci...

  14. Olopatadine Nasal Spray

    MedlinePLUS

    ... may spread germs.Olopatadine nasal spray controls the symptoms of seasonal allergic rhinitis, but does not cure these condition. Continue to use olopatadine nasal spray even if you feel well and are not experiencing these symptoms, unless your doctor has told you to use ...

  15. Applications of sprayed coatings

    NASA Astrophysics Data System (ADS)

    Steffens, H. D.; Malik, M.

    1980-03-01

    Service demands of the coating properties of sprayed coatings are classified as: preventing, fretting, wear, and corrosion; controlled abradability; and thermal barrier. Developments in both coating techniques and coating materials which have allowed production of coatings which match the performance demands are considered. Applications of sprayed coatings in aircraft components are discussed.

  16. Simplifying pyrolysis; using gasification to produce corn stover and wheat straw biochar for sorptive and horitcultural media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar is a renewable, useful material that can be utilized in many different applications. Biochar is commonly produced via pyrolysis methods using a retort-style oven with inert gas. Gasification is another method that can utilize pyrolysis to produce biochar, but with the advantage of not requir...

  17. Environmentally compatible spray cement

    SciTech Connect

    Loeschnig, P.

    1995-12-31

    Within the framework of a European research project, Heidelberger Zement developed a quickly setting and hardening binder for shotcrete, called Chronolith S, which avoids the application of setting accelerators. Density and strength of the shotcrete produced with this spray cement correspond to those of an unaccelerated shotcrete. An increased hazard for the heading team and for the environment, which may occur when applying setting accelerators, can be excluded here. Owing to the special setting properties of a spray cement, the process engineering for its manufacturing is of great importance. The treatment of a spray cement as a dry concrete with kiln-dried aggregates is possible without any problems. The use of a naturally damp pre-batched mixture is possible with Chronolith S but requires special process engineering; spray cement and damp aggregate are mixed with one another immediately before entering the spraying machinery.

  18. Corn and sorghum performance are affected by irrigation application method: SDI versus mid-elevation spray irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation application method can impact crop water use and water use efficiency (WUE), but the mechanisms involved are incompletely understood, particularly in terms of the water and energy balances during the growing season from pre-irrigation through the planting, early growth and yield developme...

  19. Corn and sorghum performance are affected by irrigation application method: SDI versus Mid-elevation spray irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is known that irrigation application method can impact crop water use and water use efficiency, but the mechanisms involved are incompletely understood, particularly in terms of the water and energy balances during the growing season from pre-irrigation through planting, early growth and yield de...

  20. Corn and sorghum performance affected by irrigation application method:SDI versus mid-elevation spray irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is known that irrigation application method can impact crop water use and water use efficiency, but the mechanisms involved are incompletely understood, particularly in terms of the water and energy balances during the growing season from pre-irrigation through planting, early growth and yield de...