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Sample records for assisted chemical vapour

  1. Aerosol assisted chemical vapour deposition of germanium thin ...

    Indian Academy of Sciences (India)

    Diethyl germanium bis-picolinate, [Et2Ge(O2CC5H4N)2], and trimethyl germanium quinaldate, [Me3Ge(O2CC9H6N)], have been used as precursors for deposition of thin films of germanium by aerosol assisted chemical vapour deposition (AACVD). The thermogravimetric analysis revealed complete volatilization of ...

  2. Plasma Assisted Chemical Vapour Deposition – Technological Design Of Functional Coatings

    Directory of Open Access Journals (Sweden)

    Januś M.

    2015-06-01

    Full Text Available Plasma Assisted Chemical Vapour Deposition (PA CVD method allows to deposit of homogeneous, well-adhesive coatings at lower temperature on different substrates. Plasmochemical treatment significantly impacts on physicochemical parameters of modified surfaces. In this study we present the overview of the possibilities of plasma processes for the deposition of diamond-like carbon coatings doped Si and/or N atoms on the Ti Grade2, aluminum-zinc alloy and polyetherketone substrate. Depending on the type of modified substrate had improved the corrosion properties including biocompatibility of titanium surface, increase of surface hardness with deposition of good adhesion and fine-grained coatings (in the case of Al-Zn alloy and improving of the wear resistance (in the case of PEEK substrate.

  3. Durability of silver nanoparticulate films within a silica matrix by flame assisted chemical vapour deposition for biocidal applications.

    Science.gov (United States)

    Cook, Ian; Shee, David W; Foster, Howard A; Varghese, Sajnu

    2011-09-01

    Healthcare acquired infection (HCAI) rates have come under increasing scrutiny in recent years and been a major priority for health professionals in the UK and elsewhere. Of particular concern is the rise of so called 'superbugs', or those resistant to conventional antibiotics, such as Escherichia coli, Clostridium difficile and methicillin resistant Staphylococcus aureus (MRSA). The reasons for this rise are many and complex, but one important factor is bacterial survival rates on wards and other hospital areas. In this respect, nanostructured biocidal surfaces offer a potentially powerful weapon in the fight against HCAI. In addition to providing a toxic environment to a range of infectious disease-causing bacteria (while remaining harmless to human health), any potential bioactive coated surface is required to be durable enough to withstand regular hospital cleaning methods without a reduction in biocidal activity over time and be economically viable to mass produce. The flame assisted chemical vapour deposition (FACVD) of silver and silver/silica films offer a means of producing such surfaces. In this work, we report investigations into a wide range of experimental factors and parameters affecting film durability, including burner head design and relative water vapour content in the flame environment. The produced films were assessed in terms of durability (by scratch testing) and relative silver content using glow discharge optical emission spectroscopy (GDOES).

  4. Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism

    Science.gov (United States)

    Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

    2016-01-01

    Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs. PMID:27334232

  5. Growth and electro-optical properties of Ga-doped ZnO films prepared by aerosol assisted chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shuqun [School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Carraro, Giorgio [Department of Chemistry and INSTM, Padova University, Padova 35131 (Italy); Barreca, Davide [CNR-IENI and INSTM, Department of Chemistry, Padova University, Padova 35131 (Italy); Binions, Russell [School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2015-06-01

    Transparent conductive Ga-doped ZnO thin films were deposited onto glass substrates by a low-cost aerosol assisted chemical vapour deposition technique and the effect of gallium content on the ZnO film growth behaviour and opto-electronic properties was systematically investigated. It is found that, upon increasing Ga addition, the ZnO film crystallinity exhibits a continuous reduction in quality associated with the preferential orientation transformed from (002) to (102). The (002) oriented samples had a microstructure of parallel columnar grains while the (102) oriented coating was thickened by overlapping particles. The ZnO:Ga coatings exhibit high carrier concentration (up to 4.1 × 10{sup 20} cm{sup −3}) but low carrier mobility (up to 0.8 cm{sup 2} V{sup −1} s{sup −1}), resulting in a minimum resistivity value of 2.3 × 10{sup −2} Ω cm. The inferior carrier mobility performance could result from a profound ionized and neutral impurity scattering effect. Good visible transmittance (≈ 70–80%) is observed in these ZnO:Ga films and samples with higher carrier density present better infrared reflection performance (up to 37.2% at 2500 nm). - Highlights: • Aerosol assisted chemical vapour deposition of doped zinc oxide thin films • Gallium doping and opto-electronic properties systemically investigated • Growth mechanism changed by % gallium incorporation.

  6. Autonomous Chemical Vapour Detection by Micro UAV

    Directory of Open Access Journals (Sweden)

    Kent Rosser

    2015-12-01

    Full Text Available The ability to remotely detect and map chemical vapour clouds in open air environments is a topic of significant interest to both defence and civilian communities. In this study, we integrate a prototype miniature colorimetric chemical sensor developed for methyl salicylate (MeS, as a model chemical vapour, into a micro unmanned aerial vehicle (UAV, and perform flights through a raised MeS vapour cloud. Our results show that that the system is capable of detecting MeS vapours at low ppm concentration in real-time flight and rapidly sending this information to users by on-board telemetry. Further, the results also indicate that the sensor is capable of distinguishing “clean” air from “dirty”, multiple times per flight, allowing us to look towards autonomous cloud mapping and source localization applications. Further development will focus on a broader range of integrated sensors, increased autonomy of detection and improved engineering of the system.

  7. Copper-Assisted Direct Growth of Vertical Graphene Nanosheets on Glass Substrates by Low-Temperature Plasma-Enhanced Chemical Vapour Deposition Process.

    Science.gov (United States)

    Ma, Yifei; Jang, Haegyu; Kim, Sun Jung; Pang, Changhyun; Chae, Heeyeop

    2015-12-01

    Vertical graphene (VG) nanosheets are directly grown below 500 °C on glass substrates by a one-step copper-assisted plasma-enhanced chemical vapour deposition (PECVD) process. A piece of copper foil is located around a glass substrate as a catalyst in the process. The effect of the copper catalyst on the vertical graphene is evaluated in terms of film morphology, growth rate, carbon density in the plasma and film resistance. The growth rate of the vertical graphene is enhanced by a factor of 5.6 with the copper catalyst with denser vertical graphene. The analysis of optical emission spectra suggests that the carbon radical density is increased with the copper catalyst. Highly conductive VG films having 800 Ω/□ are grown on glass substrates with Cu catalyst at a relatively low temperature.

  8. Microscopic characterisation of suspended graphene grown by chemical vapour deposition

    NARCIS (Netherlands)

    Bignardi, L.; Dorp, W.F. van; Gottardi, S.; Ivashenko, O.; Dudin, P.; Barinov, A.; de Hosson, J.T.M.; Stöhr, M.; Rudolf, P.

    2013-01-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron

  9. Morphology of carbon nanotubes prepared via chemical vapour ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Small angle neutron scattering (SANS) has been utilized to study the morphology of the multi-walled carbon nanotubes prepared by chemical vapour deposition of acetylene. The effects of various synthesis parameters like temperature, catalyst concentration and catalyst support on the size distribution of ...

  10. Morphology of carbon nanotubes prepared via chemical vapour ...

    Indian Academy of Sciences (India)

    Morphology of carbon nanotubes prepared via chemical vapour deposition technique using acetylene: A small angle neutron scattering investigation. D SEN1,∗, K DASGUPTA2, J BAHADUR1, S MAZUMDER1 and. D SATHIYAMOORTHY2. 1Solid State Physics; 2Powder Metallurgy Division, Bhabha Atomic Research ...

  11. Low pressure chemical vapour deposition at quasi-high flow

    NARCIS (Netherlands)

    Holleman, J.; Middelhoek, Jan

    1984-01-01

    A new chemical vapour deposition (CVD) technique is presented. It is especially advantageous for the deposition of compound materials. The technique improves the uniformity and reproducibility of the deposition. The economical use of gaseous reactants is improved by a factor varying between 5 and

  12. Influence of hydrogen on chemical vapour synthesis of different ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The role of hydrogen in the catalytic chemical vapour deposition of carbon nanotubes using sputtered nickel thin film as a catalyst is explained in this work. The growth of different carbon nanostruc- tures with the variation in the precursor gas content was studied by keeping all other process parameters constant ...

  13. Chemical vapour deposition of carbon nanotubes

    CSIR Research Space (South Africa)

    Arendse, CJ

    2006-02-01

    Full Text Available exhibit exceptional chemical and physical properties related to toughness, chemical inertness, magnetism, and electrical and thermal conductivity. A variety of preparation methods to synthesise CNTs are known, e.g. carbon-arc discharge, laser ablation...

  14. Deposition of cobalt and nickel sulfide thin films from thio- and alkylthio-urea complexes as precursors via the aerosol assisted chemical vapour deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Mgabi, L.P.; Dladla, B.S. [Department of Chemistry, University of Zululand, Private bag X1001 KwaDlangezwa, 3880 (South Africa); Malik, M.A. [School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Garje, Shivram S. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Akhtar, J. [Nanoscience and Materials Synthesis Lab, Department of Physics, COMSATS, Institute of Information Technology (CIIT), Chak shahzad, Islamabad (Pakistan); Revaprasadu, N., E-mail: RevaprasaduN@unizulu.ac.za [Department of Chemistry, University of Zululand, Private bag X1001 KwaDlangezwa, 3880 (South Africa)

    2014-08-01

    We report the synthesis of Co(II) and Ni(II) thiourea and alkylthiourea complexes by reacting the metal salts (CoCl{sub 2} and NiCl{sub 2}) with the thiourea, phenylthiourea and dicyclohexylthiourea ligands in a 1:2 ratio. The complexes, [CoCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (I), [CoCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2} (II) and [CoCI{sub 2}(SC(NHC{sub 6}H{sub 11}){sub 2}){sub 2}] (III), [NiCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (IV), [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) and [NiCl{sub 2}(SC(NHC{sub 6}H{sub 11}){sub 2}){sub 2}] (VI) were characterized by C, H, N analysis and Fourier transform infrared spectroscopy. Thermogravimetric analysis shows that all complexes undergo a two step decomposition process except for [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) which decomposes in a single step. The complexes were used as single-source precursors for the deposition of cobalt sulfide and nickel sulfide thin films by aerosol assisted chemical vapor deposition at temperatures between 350 an 500 °C. The crystallinity of the films was determined by X-ray diffraction and their morphology was determined by scanning electron microscopy. The morphology of the cobalt sulfide thin films varies from randomly oriented platelets, to granulated spheres and cubes as the precursor and deposition conditions are changed. For nickel sulfide, the [NiCl{sub 2}(CS(NH{sub 2}){sub 2}){sub 2}] (IV) complex gave rods whereas the [NiCl{sub 2}(CSNHC{sub 6}H{sub 5}NH{sub 2}){sub 2}] (V) produced spherical particles. - Highlights: • We report the synthesis of Co(II) and Ni(II) thiourea and alkylthiourea complexes. • C, H, N analysis and Fourier transform infrared spectroscopy characterization • NiS and CoS thin films deposited by aerosol assisted chemical vapor deposition • X-ray diffraction characterization of the phase of the films • Film morphology determined by scanning electron microscopy.

  15. Laser-Induced Chemical Vapour Deposition of Silicon Carbonitride

    OpenAIRE

    Besling, W.; van der Put, P.; Schoonman, J.

    1995-01-01

    Laser-induced Chemical Vapour Deposition of silicon carbonitride coatings and powders has been investigated using hexamethyldisilazane (HMDS) and ammonia as reactants. An industrial CW CO2-laser in parallel configuration has been used to heat up the reactant gases. HMDS dissociates in the laser beam and reactive radicals are formed which increase rapidly in molecular weight by an addition mechanism. Dense polymer-like silicon carbonitride thin films and nanosized powders are formed depending ...

  16. CHEMICAL VAPOUR DEPOSITION OF THE Al-O-N SYSTEM

    OpenAIRE

    Aspar, B.; Armas, B.; Combescure, C.; Thenegal, D.

    1991-01-01

    Using chemical vapour deposition, aluminium - oxygen-nitrogen coatings have been synthesized with aluminium trichloride, hydrogen, ammonia and nitrous oxide. The composition of the equilibrium phases is first determined by a thermodynamic calculation. The only AlON phase we investigate is ([MATH]) spinel aluminium oxynitride and it is considered as a stoichiometric phase with a composition of Al7O9N. The results indicate the existence fields of aluminium nitride and alumina and show the diffi...

  17. Chemical Vapour Deposition of Gas Sensitive Metal Oxides

    OpenAIRE

    Stella Vallejos; Francesco Di Maggio; Tahira Shujah; Chris Blackman

    2016-01-01

    This article presents a review of recent research efforts and developments for the fabrication of metal-oxide gas sensors using chemical vapour deposition (CVD), presenting its potential advantages as a materials synthesis technique for gas sensors along with a discussion of their sensing performance. Thin films typically have poorer gas sensing performance compared to traditional screen printed equivalents, attributed to reduced porosity, but the ability to integrate materials directly with ...

  18. Chemical Vapour Deposition of Large Area Graphene

    DEFF Research Database (Denmark)

    Larsen, Martin Benjamin Barbour Spanget

    Chemical Vapor Deposition (CVD) is a viable technique for fabrication of large areas of graphene. CVD fabrication is the most prominent and common way of fabricating graphene in industry. In this thesis I have attempted to optimize a growth recipe and catalyst layer for CVD fabrication of uniform......, single layer, and high carrier mobility large area graphene. The main goals of this work are; (1) explore the graphene growth mechanics in a low pressure cold-wall CVD system on a copper substrate, and (2) optimize the process of growing high quality graphene in terms of carrier mobility, and crystal...... structure. Optimization of a process for graphene growth on commercially available copper foil is limited by the number of aluminium oxide particles on the surface of the catalyst. By replacing the copper foil with a thin deposited copper film on a SiO2/Si or c-plane sapphire wafer the particles can...

  19. Silicon nanowire arrays as learning chemical vapour classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Niskanen, A O; Colli, A; White, R; Li, H W; Spigone, E; Kivioja, J M, E-mail: antti.niskanen@nokia.com [Nokia Research Center, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2011-07-22

    Nanowire field-effect transistors are a promising class of devices for various sensing applications. Apart from detecting individual chemical or biological analytes, it is especially interesting to use multiple selective sensors to look at their collective response in order to perform classification into predetermined categories. We show that non-functionalised silicon nanowire arrays can be used to robustly classify different chemical vapours using simple statistical machine learning methods. We were able to distinguish between acetone, ethanol and water with 100% accuracy while methanol, ethanol and 2-propanol were classified with 96% accuracy in ambient conditions.

  20. Chemical vapour deposited diamonds for dosimetry of radiotherapeutical beams

    Energy Technology Data Exchange (ETDEWEB)

    Bucciolini, M.; Mazzocchi, S. [Firenze Univ., Firenze (Italy). Dipartimento di Fisiopatologia Clinica; INFN, Firenze (Italy); Borchi, E.; Bruzzi, M.; Pini, S.; Sciortino, S. [Firenze Univ., Firenze (Italy). Dipartimento di Energetica; INFN, Firenze (Italy); Cirrone, G.A.P.; Guttone, G.; Raffaele, L.; Sabini, M.G. [INFN, Catania (Italy). Laboratori Nazionali del Sud

    2002-07-01

    This paper deals with the application of synthetic diamond detectors to the clinical dosimetry of photon and electron beams. It has been developed in the frame of INFN CANDIDO project and MURST Cofin. Diamonds grown with CVD (Chemical Vapour Deposition) technique have been studied; some of them are commercial samples while others have been locally synthesised. Experiments have been formed using both on-line and off-line approaches. For the off-line measurements, TL (thermoluminescent) and TSC (thermally stimulated current) techniques have been used.

  1. Evaluation of niobium dimethylamino-ethoxide for chemical vapour deposition of niobium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dabirian, Ali [Laboratory for Photonic Materials and Characterization, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, 1015 Lausanne (Switzerland); Kuzminykh, Yury, E-mail: yury.kuzminykh@empa.ch [Laboratory for Photonic Materials and Characterization, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, 1015 Lausanne (Switzerland); Laboratory for Advanced Materials Processing, Empa, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Wagner, Estelle; Benvenuti, Giacomo [3D-Oxides, 70 Rue G. Eiffel Technoparc, 01630 St Genis Pouilly (France); ABCD Technology, 12 route de Champ-Colin, 1260 Nyon (Switzerland); Rushworth, Simon [Tyndall National Institute, Lee Maltings, Dyke Parade, Cork (Ireland); Hoffmann, Patrik, E-mail: patrik.hoffmann@empa.ch [Laboratory for Photonic Materials and Characterization, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, 1015 Lausanne (Switzerland); Laboratory for Advanced Materials Processing, Empa, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun (Switzerland)

    2014-11-28

    Chemical vapour deposition (CVD) processes depend on the availability of suitable precursors. Precursors that deliver a stable vapour pressure are favourable in classical CVD processes, as they ensure process reproducibility. In high vacuum CVD (HV-CVD) process vapour pressure stability of the precursor is of particular importance, since no carrier gas assisted transport can be used. The dimeric Nb{sub 2}(OEt){sub 10} does not fulfil this requirement since it partially dissociates upon heating. Dimethylamino functionalization of an ethoxy ligand of Nb(OEt){sub 5} acts as an octahedral field completing entity and leads to Nb(OEt){sub 4}(dmae). We show that Nb(OEt){sub 4}(dmae) evaporates as monomeric molecule and ensures a stable vapour pressure and, consequently, stable flow. A set of HV-CVD experiments were conducted using this precursor by projecting a graded molecular beam of the precursor onto the substrate at deposition temperatures from 320 °C to 650 °C. Film growth rates ranging from 8 nm·h{sup −1} to values larger than 400 nm·h{sup −1} can be obtained in this system illustrating the high level of control available over the film growth process. Classical CVD limiting conditions along with the recently reported adsorption–reaction limited conditions are observed and the chemical composition, and microstructural and optical properties of the films are related to the corresponding growth regime. Nb(OEt){sub 4}(dmae) provides a large process window of deposition temperatures and precursor fluxes over which carbon-free and polycrystalline niobium oxide films with growth rates proportional to precursor flux are obtained. This feature makes Nb(OEt){sub 4}(dmae) an attractive precursor for combinatorial CVD of niobium containing complex oxide films that are finding an increasing interest in photonics and photoelectrochemical water splitting applications. The adsorption–reaction limited conditions provide extremely small growth rates comparable to an

  2. Controlled nanostructured silver coated surfaces by atmospheric pressure chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sheel, D.W.; Brook, L.A.; Yates, H.M. [Institute for Materials Research, Salford University, Manchester, M5 4 WT (United Kingdom)

    2008-02-15

    Thin film silver has been widely reported for its interesting properties. In this paper we describe a route to produce controlled nanostructured silver layers. A combination of Flame Assisted Chemical Vapour Deposition at atmospheric pressure, with low cost and a low toxicity silver precursor, was used to generate coatings of structured silver surfaces on glass. This approach gives a high degree of control of surface structure, density and topography. These layers have potential applications in areas such as catalysis, photo-activity and for biocidal surfaces. Our results indicate very high biocidal activity where the nano-structure is proposed as playing a significant role. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  3. The Chemical Vapour Deposition of Tantalum - in long narrow channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki

    concentrations in order to document the effects of these properties on the tantalum deposition rates. A kinetic model is developed upon the foundation of a Computational Fluid Dynamics (CFD) and Thermal model in order to broaden the understanding of the process and to identify the key control parameters...... mechanism of reaction, TaCl3 is found to have a lot of relevance such that it is the main precursor to the surface reaction and that the overall deposition rates follow its abundance. An experiment with a real plate heat exchanger is also done and the corresponding model implemented with satisfactory...... use as a construction material for process equipment, with the cheaper alternative being the construction of equipment from steel and then protecting it with a thin but efficacious layer of tantalum. Chemical Vapour Deposition (CVD) is chosen as the most effective process to apply thin corrosion...

  4. Plasma Enhanced Chemical Vapour Deposition of Horizontally Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Matthew T. Cole

    2013-05-01

    Full Text Available A plasma-enhanced chemical vapour deposition reactor has been developed to synthesis horizontally aligned carbon nanotubes. The width of the aligning sheath was modelled based on a collisionless, quasi-neutral, Child’s law ion sheath where these estimates were empirically validated by direct Langmuir probe measurements, thereby confirming the proposed reactors ability to extend the existing sheath fields by up to 7 mm. A 7 mbar growth atmosphere combined with a 25 W plasma permitted the concurrent growth and alignment of carbon nanotubes with electric fields of the order of 0.04 V μm−1 with linear packing densities of up to ~5 × 104 cm−1. These results open up the potential for multi-directional in situ alignment of carbon nanotubes providing one viable route to the fabrication of many novel optoelectronic devices.

  5. Thermoluminescence characterisation of chemical vapour deposited diamond films

    CERN Document Server

    Mazzocchi, S; Bucciolini, M; Cuttone, G; Pini, S; Sabini, M G; Sciortino, S

    2002-01-01

    The thermoluminescence (TL) characteristics of a set of six chemical vapour deposited diamond films have been studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterisation has been performed by means of Raman spectroscopy. Their TL responses have been tested with radiotherapy beams ( sup 6 sup 0 Co photons, photons and electrons from a linear accelerator (Linac), 26 MeV protons from a TANDEM accelerator) in the dose range 0.1-7 Gy. The dosimetric characterisation has yielded a very good reproducibility, a very low dependence of the TL response on the type of particle and independence of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the diamond samples compares favourably with that of standard TLD100 dosimeters.

  6. Chemical Vapour Deposition of Gas Sensitive Metal Oxides

    Directory of Open Access Journals (Sweden)

    Stella Vallejos

    2016-03-01

    Full Text Available This article presents a review of recent research efforts and developments for the fabrication of metal-oxide gas sensors using chemical vapour deposition (CVD, presenting its potential advantages as a materials synthesis technique for gas sensors along with a discussion of their sensing performance. Thin films typically have poorer gas sensing performance compared to traditional screen printed equivalents, attributed to reduced porosity, but the ability to integrate materials directly with the sensor platform provides important process benefits compared to competing synthetic techniques. We conclude that these advantages are likely to drive increased interest in the use of CVD for gas sensor materials over the next decade, whilst the ability to manipulate deposition conditions to alter microstructure can help mitigate the potentially reduced performance in thin films, hence the current prospects for use of CVD in this field look excellent.

  7. Laser diagnostics of chemical vapour deposition of diamond films

    CERN Document Server

    Wills, J B

    2002-01-01

    Cavity ring down spectroscopy (CRDS) has been used to make diagnostic measurements of chemically activated CH sub 4 / H sub 2 gas mixtures during the chemical vapour deposition (CVD) of thin diamond films. Absolute absorbances, concentrations and temperatures are presented for CH sub 3 , NH and C sub 2 H sub 2 in a hot filament (HF) activated gas mixture and CH, C sub 2 and C sub 2 H sub 2 in a DC arc plasma jet activated mixture. Measurements of the radical species were made using a pulsed dye laser system to generate tuneable visible and UV wavelengths. These species have greatest concentration in the hottest, activated regions of the reactors. Spatial profiling of the number densities of CH sub 3 and NH radicals have been used as stringent tests of predictions of radical absorbance and number densities made by 3-D numerical simulations, with near quantitative agreement. O sub 2 has been shown to reside in the activated region of the Bristol DC arc jet at concentrations (approx 10 sup 1 sup 3 molecules / cm...

  8. Giant spin Hall effect in graphene grown by chemical vapour deposition

    OpenAIRE

    Balakrishnan, Jayakumar; Koon, Gavin Kok Wai; Avsar, Ahmet; Ho, Yuda; Lee, Jong Hak; Jaiswal, Manu; Baeck, Seung Jae; Ahn, Jong Hyun; Ferreira, Aires; Cazalilla, Miguel A.; Neto, Antonio H Castro; Özyilmaz, Barbaros

    2014-01-01

    Advances in large-area graphene synthesis via chemical vapour deposition on metals like copper were instrumental in the demonstration of graphene-based novel, wafer-scale electronic circuits and proof-of-concept applications such as flexible touch panels. Here, we show that graphene grown by chemical vapour deposition on copper is equally promising for spintronics applications. In contrast to natural graphene, our experiments demonstrate that chemically synthesized graphene has a strong spin-...

  9. Chemical vapour deposition of diamond coatings onto molybdenum dental tools

    Science.gov (United States)

    Amar, M.; Ahmed, W.; Sein, H.; Jones, A. N.; Rego, C. A.

    2003-10-01

    The growth of polycrystalline diamond films onto molybdenum rods and dental burrs by using a new hot filament chemical vapour deposition (CVD) system has been investigated. Negative dc bias voltage relative to the filament was applied to the molybdenum substrate prior to deposition. This led to much improved film adhesion and increased nucleation density. There was a factor of four improvement in the adhesive force from 20 to 80 N when a bias voltage of -300 V was employed to the substrate. The CVD coated molybdenum dental burr was found to give much improved performance and lifetime compared to the conventional sintered diamond burr. The CVD diamond burr showed no signs of deterioration even after 1000 operations whereas the conventional sintered diamond burrs were ineffective after between 30 and 60 operations. This represents a 30-fold improvement when CVD is applied. CVD diamond growth onto dental burrs has the potential for replacing exciting technology by achieving better performance and lifetime in a cost-effective manner.

  10. The atmospheric chemical vapour deposition of coatings on glass

    CERN Document Server

    Sanderson, K D

    1996-01-01

    The deposition of thin films of indium oxide, tin doped indium oxide (ITO) and titanium nitride for solar control applications have been investigated by Atmospheric Chemical Vapour Deposition (APCVD). Experimental details of the deposition system and the techniques used to characterise the films are presented. Results from investigations into the deposition parameters, the film microstructure and film material properties are discussed. A range of precursors were investigated for the deposition of indium oxide. The effect of pro-mixing the vaporised precursor with an oxidant source and the deposition temperature has been studied. Polycrystalline In sub 2 O sub 3 films with a resistivity of 1.1 - 3x10 sup - sup 3 OMEGA cm were obtained with ln(thd) sub 3 , oxygen and nitrogen. The growth of ITO films from ln(thd) sub 3 , oxygen and a range of tin dopants is also presented. The effect of the dopant precursor, the doping concentration, deposition temperature and the effect of additives on film growth and microstr...

  11. A computer-controlled system for generation of chemical vapours in in vitro dermal uptake studies.

    Science.gov (United States)

    Rauma, Matias; Johanson, Gunnar

    2007-02-01

    Recent work in our laboratory suggests that dermal absorption and desorption of volatile chemicals may be assessed in vitro by thermogravimetric analysis (TGA), i.e. by passing chemical vapour over a piece of skin while recording the weight increase at constant temperature and humidity. This paper describes a high-precision automated vapour-generating system for use with the TGA equipment. The system consists of computer-controlled magnetic valves and mass flow meters that split and redirect a flow of pure, dry air through different stainless-steel gas wash bottles thermostated to 25.00+/-0.05 degrees C. Each wash bottle is filled with a neat volatile chemical and designed so that the air leaving reaches 100% saturation within seconds, as shown with cyclohexanone. The air leaving the wash bottles are combined and directed via stainless-steel liners to the skin piece in the TGA chamber. The liners are heated to 30 degrees C to prevent condensation of water or chemical. Special computer software was developed to allow automatic runs with different wash bottles (chemicals) and air flows over several days. A number of measurements were made to characterize the stability and reproducibility of the vapour-generating system. We have developed a computer-controlled vapour-generating system for use in measurements of dermal absorption of chemicals by thermal gravimetry. The system has high stability and reproducibility and produces little noise.

  12. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    NARCIS (Netherlands)

    Sharma, K.; Williams, B.L.; Mittal, A.; Knoops, H.C.M.; Kniknie, B.J.; Bakker, N.J.; Kessels, W.M.M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing

  13. Properties of alumina films by atmospheric pressure metal-organic chemical vapour deposition

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1994-01-01

    Thin alumina films were deposited at low temperatures (290–420°C) on stainless steel, type AISI 304. The deposition process was carried out in nitrogen by metal-organic chemical vapour deposition using aluminum tri-sec-butoxide. The film properties including the protection of the underlying

  14. The effect of air permeability of chemical protective clothing material on clothing vapour resistance

    NARCIS (Netherlands)

    Havenith, G.; Vuister, R.; Wammes, L.

    1996-01-01

    One of the major problems associated with Chemical Warfare Protective Clothing (CW) is the additional heat load created by the garments. For CW-overgarments, research in the direction of reducing material thickness and thus heat and vapour resistance have not resulted in major improvements. The

  15. Applicability of chemical vapour polishing of additive manufactured parts to meet production-quality

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    The Fused Deposition Modelling (FDM) method is the most rapidly growing Additive Manufacturing (AM) method[1]. FDM employs a 2.5D deposition scheme which induce a step-ladder shaped surface definition [2], with seams of the individual layers clearly visible[3]. This paper investigate to which...... extend chemical vapour polishing can be applied to eliminate the layered surfaces from FDM, so that a polished surface quality is obtained. It is quantified to what extend parts can be vapour polished and how geometrical and mechanical properties alter. The fundamental question is whether the surfaces...... of FDM manufactured parts can be taken from their current quality into the precision engineering domain....

  16. Hot-wire chemical vapour deposition of carbon nanotubes

    CSIR Research Space (South Africa)

    Cummings, FR

    2006-07-01

    Full Text Available Owing entirely to their structure, carbon nanotubes (CNTs) possess some of the most remarkable chemical and physical properties. More specifically, they exhibit exceptional strength and toughness, chemical inertness, magnetism, and electrical...

  17. Heat stress in chemical protective clothing: Porosity and vapour resistance

    NARCIS (Netherlands)

    Havenith, G.; Hartog, E.A. den; Martini, S.

    2011-01-01

    Heat strain in chemical protective clothing is an important factor in industrial and military practice. Various improvements to the clothing to alleviate strain while maintaining protection have been attempted. More recently, selectively permeable membranes have been introduced to improve

  18. Si-nanocrystal-based LEDs fabricated by ion implantation and plasma-enhanced chemical vapour deposition

    Science.gov (United States)

    Perálvarez, M.; Barreto, J.; Carreras, Josep; Morales, A.; Navarro-Urrios, D.; Lebour, Y.; Domínguez, C.; Garrido, B.

    2009-10-01

    An in-depth study of the physical and electrical properties of Si-nanocrystal-based MOSLEDs is presented. The active layers were fabricated with different concentrations of Si by both ion implantation and plasma-enhanced chemical vapour deposition. Devices fabricated by ion implantation exhibit a combination of direct current and field-effect luminescence under a bipolar pulsed excitation. The onset of the emission decreases with the Si excess from 6 to 3 V. The direct current emission is attributed to impact ionization and is associated with the reasonably high current levels observed in current-voltage measurements. This behaviour is in good agreement with transmission electron microscopy images that revealed a continuous and uniform Si nanocrystal distribution. The emission power efficiency is relatively low, ~10-3%, and the emission intensity exhibits fast degradation rates, as revealed from accelerated ageing experiments. Devices fabricated by chemical deposition only exhibit field-effect luminescence, whose onset decreases with the Si excess from 20 to 6 V. The absence of the continuous emission is explained by the observation of a 5 nm region free of nanocrystals, which strongly reduces the direct current through the gate. The main benefit of having this nanocrystal-free region is that tunnelling current flow assisted by nanocrystals is blocked by the SiO2 stack so that power consumption is strongly reduced, which in return increases the device power efficiency up to 0.1%. In addition, the accelerated ageing studies reveal a 50% degradation rate reduction as compared to implanted structures.

  19. Si-nanocrystal-based LEDs fabricated by ion implantation and plasma-enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Peralvarez, M; Carreras, Josep; Navarro-Urrios, D; Lebour, Y; Garrido, B [MIND, IN2UB, Department of Electronics, University of Barcelona, C/Marti i Franques 1, PL2, E-08028 Barcelona (Spain); Barreto, J; DomInguez, C [IMB-CNM, CSIC, Bellaterra, E-08193 Barcelona (Spain); Morales, A, E-mail: mperalvarez@el.ub.e [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico)

    2009-10-07

    An in-depth study of the physical and electrical properties of Si-nanocrystal-based MOSLEDs is presented. The active layers were fabricated with different concentrations of Si by both ion implantation and plasma-enhanced chemical vapour deposition. Devices fabricated by ion implantation exhibit a combination of direct current and field-effect luminescence under a bipolar pulsed excitation. The onset of the emission decreases with the Si excess from 6 to 3 V. The direct current emission is attributed to impact ionization and is associated with the reasonably high current levels observed in current-voltage measurements. This behaviour is in good agreement with transmission electron microscopy images that revealed a continuous and uniform Si nanocrystal distribution. The emission power efficiency is relatively low, {approx}10{sup -3}%, and the emission intensity exhibits fast degradation rates, as revealed from accelerated ageing experiments. Devices fabricated by chemical deposition only exhibit field-effect luminescence, whose onset decreases with the Si excess from 20 to 6 V. The absence of the continuous emission is explained by the observation of a 5 nm region free of nanocrystals, which strongly reduces the direct current through the gate. The main benefit of having this nanocrystal-free region is that tunnelling current flow assisted by nanocrystals is blocked by the SiO{sub 2} stack so that power consumption is strongly reduced, which in return increases the device power efficiency up to 0.1%. In addition, the accelerated ageing studies reveal a 50% degradation rate reduction as compared to implanted structures.

  20. Straining Graphene by Chemical Vapour Deposition Growth on Copper

    OpenAIRE

    Yu, Victor; Whiteway, Eric; Maassen, Jesse; Hilke, Michael

    2011-01-01

    Strain can be used as an alternate way to tune the electronic properties of graphene. Here we demonstrate that it is possible to tune the uniform strain of graphene simply by changing the chemical vapor deposition growth temperature of graphene on copper. Due to the cooling of the graphene on copper system, we can induce a uniform compressive strain on graphene. The strain is analyzed by Raman spectroscopy, where a shift in the 2D peak is observed and compared to our ab initio calculations of...

  1. Graphene growth from reduced graphene oxide by chemical vapour deposition: seeded growth accompanied by restoration

    OpenAIRE

    Sung-Jin Chang; Moon Seop Hyun; Sung Myung; Min-A Kang; Jung Ho Yoo; Kyoung G. Lee; Bong Gill Choi; Youngji Cho; Gaehang Lee; Tae Jung Park

    2016-01-01

    Understanding the underlying mechanisms involved in graphene growth via chemical vapour deposition (CVD) is critical for precise control of the characteristics of graphene. Despite much effort, the actual processes behind graphene synthesis still remain to be elucidated in a large number of aspects. Herein, we report the evolution of graphene properties during in-plane growth of graphene from reduced graphene oxide (RGO) on copper (Cu) via methane CVD. While graphene is laterally grown from R...

  2. Consolidation and conversion of carbon powders into TiC by reactive chemical vapour infiltration

    OpenAIRE

    Ledain, Olivier; JACQUES, Sylvain; Maillé, Laurence

    2016-01-01

    International audience; Ceramic samples were prepared using a hybrid process in which the ceramic powder route was combined with Reactive Chemical Vapour Infiltration, a new gas phase route. In this technique, a carbide growth occurs from the conversion of a carbon-bearing powder and slows down with increase in carbide thickness due to solid-state diffusion limitation. This self-limitation is expected to allow a self-regulation of the growth between the interior and the surface of the sample ...

  3. Creep of chemically vapour deposited SiC fibres

    Science.gov (United States)

    Dicarlo, J. A.

    1986-01-01

    The creep, thermal expansion, and elastic modulus properties for chemically vapor deposited SiC fibers were measured between 1000 and 1500 C. Creep strain was observed to increase logarithmically with time, monotonically with temperature, and linearly with tensile stress up to 600 MPa. The controlling activation energy was 480 + or - 20 kJ/mole. Thermal pretreatments near 1200 and 1450 C were found to significantly reduce fiber creep. These results coupled with creep recovery observations indicate that below 1400 C fiber creep is anelastic with negligible plastic component. This allowed a simple predictive method to be developed for describing fiber total deformation as a function of time, temperature, and stress. Mechanistic analysis of the property data suggests that fiber creep is the result of beta-SiC grain boundary sliding controlled by a small percent of free silicon in the grain boundaries.

  4. Novel antibacterial silver-silica surface coatings prepared by chemical vapour deposition for infection control.

    Science.gov (United States)

    Varghese, S; Elfakhri, S; Sheel, D W; Sheel, P; Bolton, F J; Foster, H A

    2013-11-01

    Environmental contamination plays an important role in the transmission of infections, especially healthcare-associated infections. Disinfection transiently reduces contamination, but surfaces can rapidly become re-contaminated. Antimicrobial surfaces may partially overcome that limitation. The antimicrobial activity of novel surface coatings containing silver and silica prepared using a flame-assisted chemical vapour deposition method on both glass and ceramic tiles was investigated. Antimicrobial activity against a variety of bacteria including recent clinical isolates was investigated based on the BS ISO 22196:2007 Plastics--Measurement of antibacterial activity on plastics surfaces, British Standards Institute, London, method. Activity on natural contamination in an in use test in a toilet facility was also determined. Activity on standard test strains gave a log10 reduction of five after 1-4 h. The hospital isolates were more resistant, but MRSA was reduced by a log10 reduction factor of >5 after 24 h. Activity was maintained after simulated ageing and washing cycles. Contamination in situ was reduced by >99.9% after 4 months. Activity was inhibited by protein, but, although this could be overcome by increasing the amount of silver in the films, this reduced the hardness of the coating. The coatings had a good activity against standard test strains. Clinical isolates were killed more slowly but were still sensitive. The optimum composition for use therefore needs to be a balance between activity and durability. The coatings may have applications in health care by maintaining a background antimicrobial activity between standard cleaning and disinfection regimes. They may also have applications in other areas where reduction in microbial contamination is important, for example, in the food industry. © 2013 The Society for Applied Microbiology.

  5. Interface study between nanostructured tantalum nitride films and carbon nanotubes grown by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet-Fabre, B., E-mail: brigitte.bouchet-fabre@cea.fr [Nanosciences and Innovation, CEA/IRAMIS/NIMBE, CEA-Saclay, 91191 Gif sur Yvette Cedex (France); Pinault, M.; Foy, E. [Nanosciences and Innovation, CEA/IRAMIS/NIMBE, CEA-Saclay, 91191 Gif sur Yvette Cedex (France); Hugon, M.C.; Minéa, T. [Laboratoire de Physique des Gaz et des Plasmas (UMR 8578), Université Paris-Sud, Bat. 210, 91405 Orsay cedex (France); Mayne-L’Hermite, M. [Nanosciences and Innovation, CEA/IRAMIS/NIMBE, CEA-Saclay, 91191 Gif sur Yvette Cedex (France)

    2014-10-01

    Highlights: • Our paper deals with the understanding of the carbon nanotubes growth parameters following the use of specific thin nitride buffer films. • For a large choice of buffer, we use ultra thin films elaborated by the very new method: high power pulsed magnetron sputtering; it allows a larger nitrogen incorporation in the films and lead to out of equilibrium phase formation. • Then by a multiscale investigation, developing a structural, a chemical and a morphology approach, we lead to some conclusion on the correlation between the phase transition for the buffer and morphology transition for the CNTs. • That is a new and deep approach. - Abstract: We present the role of nitrogen content in tantalum nitride ultra-thin buffers, on the carbon nanotubes (CNTs) growth by chemical vapour deposition at 850 °C, assisted by ferrocene as catalyst source. Tantalum nitride (TaN{sub x}) films with a very large range of concentration x = [0, 1.8] and various nanostructures, from amorphous Ta(N) to Ta{sub 3}N{sub 5}, were deposited by Highly Pulsed Plasma Magnetron Sputtering. The buffer films are characterized after heat treatment at 850 °C, and after the CNT growth, by wide angle X-ray scattering in grazing incidence and scanning electron microscopy. The CNT diameter explored by transition electron microscopy shows an all-out value for under stoichiometric thin films (Ta{sub 1}-N{sub 1−δ}, Ta{sub 3}-N{sub 5−δ}) and a minimum value just above the stoichiometric phases (Ta{sub 1}-N{sub 1+δ}, Ta{sub 3}-N{sub 5+δ}). Firstly one shows that the buffer films under the heat treatment present surface modification highly dependent on their initial state, which influences the catalyst particles diffusion. Secondly at the stoichiometric TaN phase we show that a specific ternary phase FeTa{sub 2}O{sub 6} is formed at the interface CNT/buffer, not present in the other cases, leading to a special CNT growth condition.

  6. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    OpenAIRE

    Sharma, K; Williams, B. L.; Mittal, A.; Knoops, H. C. M.; Kniknie, B.J.; Bakker, N J; Kessels, W. M. M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C) can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO). In...

  7. Giant spin Hall effect in graphene grown by chemical vapour deposition.

    Science.gov (United States)

    Balakrishnan, Jayakumar; Koon, Gavin Kok Wai; Avsar, Ahmet; Ho, Yuda; Lee, Jong Hak; Jaiswal, Manu; Baeck, Seung-Jae; Ahn, Jong-Hyun; Ferreira, Aires; Cazalilla, Miguel A; Castro Neto, Antonio H; Özyilmaz, Barbaros

    2014-09-01

    Advances in large-area graphene synthesis via chemical vapour deposition on metals like copper were instrumental in the demonstration of graphene-based novel, wafer-scale electronic circuits and proof-of-concept applications such as flexible touch panels. Here, we show that graphene grown by chemical vapour deposition on copper is equally promising for spintronics applications. In contrast to natural graphene, our experiments demonstrate that chemically synthesized graphene has a strong spin-orbit coupling as high as 20 meV giving rise to a giant spin Hall effect. The exceptionally large spin Hall angle ~0.2 provides an important step towards graphene-based spintronics devices within existing complementary metal-oxide-semiconductor technology. Our microscopic model shows that unavoidable residual copper adatom clusters act as local spin-orbit scatterers and, in the resonant scattering limit, induce transverse spin currents with enhanced skew-scattering contribution. Our findings are confirmed independently by introducing metallic adatoms-copper, silver and gold on exfoliated graphene samples.

  8. Aerosol assisted chemical vapour deposition of germanium thin ...

    Indian Academy of Sciences (India)

    These films on oxidation under an oxygen atmosphere at 600◦C yield GeO2. Both Ge ... corrosive. To overcome these problems, research is directed to design and develop new organogermanium precursors for deposition of germanium films by CVD. Recently ... stat PGSTAT 20 (Echochimie, The Netherlands), was used.

  9. Chemical vapour deposition diamond coating on tungsten carbide dental cutting tools

    Science.gov (United States)

    Sein, H.; Ahmed, W.; Rego, C. A.; Jones, A. N.; Amar, M.; Jackson, M.; Polini, R.

    2003-10-01

    Diamond coatings on Co cemented tungsten carbide (WC-Co) hard metal tools are widely used for cutting non-ferrous metals. It is difficult to deposit diamond onto cutting tools, which generally have a complex geometry, using a single step growth process. This paper focuses on the deposition of polycrystalline diamond films onto dental tools, which possess 3D complex or cylindrical shape, employing a novel single step chemical vapour deposition (CVD) growth process. The diamond deposition is carried out in a hot filament chemical vapour deposition (HFCVD) reactor with a modified filament arrangement. The filament is mounted vertically with the drill held concentrically in between the filament coils, as opposed to the commonly used horizontal arrangement. This is a simple and inexpensive filament arrangement. In addition, the problems associated with adhesion of diamond films on WC-Co substrates are amplified in dental tools due to the very sharp edges and unpredictable cutting forces. The presence of Co, used as a binder in hard metals, generally causes poor adhesion. The amount of metallic Co on the surface can be reduced using a two step pre-treatment employing Murakami etching followed by an acid treatment. Diamond films are examined in terms of their growth rate, morphology, adhesion and cutting efficiency. We found that in the diamond coated dental tool the wear rate was reduced by a factor of three as compared to the uncoated tool.

  10. Zinc oxide nanostructures by chemical vapour deposition as anodes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Laurenti, M., E-mail: marco.laurenti@iit.it [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Garino, N. [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Porro, S.; Fontana, M. [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento, 21, 10129 Turin (Italy); Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy)

    2015-08-15

    Highlights: • ZnO nanostructures are grown by simple chemical vapour deposition. • Polycrystalline nanostructured porous thin film is obtained. • Film exhibits stable specific capacity (∼400 mA h g{sup −1}) after prolonged cycling. • CVD-grown ZnO nanostructures show promising prospects as Li-ion battery anode. - Abstract: ZnO nanostructures are grown by a simple chemical vapour deposition method directly on a stainless steel disc current collector and successfully tested in lithium cells. The structural/morphological characterization points out the presence of well-defined polycrystalline nanostructures having different shapes and a preferential orientation along the c-axis direction. In addition, the high active surface of the ZnO nanostructures, which accounts for a large electrode/electrolyte contact area, and the complete wetting with the electrolyte solution are considered to be responsible for the good electrical transport properties and the adequate electrochemical behaviour, as confirmed by cyclic voltammetry and galvanostatic charge/discharge cycling. Indeed, despite no binder or conducting additives are used, when galvanostatically tested in lithium cells, after an initial decay, the ZnO nanostructures can provide a rather stable specific capacity approaching 70 μA h cm{sup −2} (i.e., around 400 mA h g{sup −1}) after prolonged cycling at 1 C, with very high Coulombic efficiency and an overall capacity retention exceeding 62%.

  11. High-quality monolayer superconductor NbSe2grown by chemical vapour deposition.

    Science.gov (United States)

    Wang, Hong; Huang, Xiangwei; Lin, Junhao; Cui, Jian; Chen, Yu; Zhu, Chao; Liu, Fucai; Zeng, Qingsheng; Zhou, Jiadong; Yu, Peng; Wang, Xuewen; He, Haiyong; Tsang, Siu Hon; Gao, Weibo; Suenaga, Kazu; Ma, Fengcai; Yang, Changli; Lu, Li; Yu, Ting; Teo, Edwin Hang Tong; Liu, Guangtong; Liu, Zheng

    2017-08-30

    The discovery of monolayer superconductors bears consequences for both fundamental physics and device applications. Currently, the growth of superconducting monolayers can only occur under ultrahigh vacuum and on specific lattice-matched or dangling bond-free substrates, to minimize environment- and substrate-induced disorders/defects. Such severe growth requirements limit the exploration of novel two-dimensional superconductivity and related nanodevices. Here we demonstrate the experimental realization of superconductivity in a chemical vapour deposition grown monolayer material-NbSe 2 . Atomic-resolution scanning transmission electron microscope imaging reveals the atomic structure of the intrinsic point defects and grain boundaries in monolayer NbSe 2 , and confirms the low defect concentration in our high-quality film, which is the key to two-dimensional superconductivity. By using monolayer chemical vapour deposited graphene as a protective capping layer, thickness-dependent superconducting properties are observed in as-grown NbSe 2 with a transition temperature increasing from 1.0 K in monolayer to 4.56 K in 10-layer.Two-dimensional superconductors will likely have applications not only in devices, but also in the study of fundamental physics. Here, Wang et al. demonstrate the CVD growth of superconducting NbSe2 on a variety of substrates, making these novel materials increasingly accessible.

  12. Chemical vapour etching-based porous silicon and grooving: Application in silicon solar cells processing

    Energy Technology Data Exchange (ETDEWEB)

    Ben Rabha, M.; Boujmil, M.F.; Saadoun, M.; Bessais, B. [Institut National de Recherche Scientifique et Technique, Laboratoire de Photovoltaique et des Semiconducteurs, BP 95, 2050 Hammam-Lif (Tunisia)

    2005-06-01

    Sponge like porous silicon (PS) was formed by a simple and low cost chemical vapour etching (CVE) method and applied in polycrystalline silicon (mc-Si) solar cells processing. The CVE method consists of exposing Si wafers to HNO{sub 3}/HF vapours. It was shown that 8 min of HNO{sub 3}/HF CVE (volume ratio = 1/7) is sufficient to form optimized PS layers on the emitter of mc-Si cells. The CVE-based PS can simultaneously passivate the Si surface and serves as an effective antireflection coating (ARC). As a result, the reflectivity decreases by about 60% of its initial value and the internal quantum efficiency is improved, particularly in the short wavelength region. For acid vapours rich in HNO{sub 3} (HNO{sub 3}/HF >1/4), the CVE method favours the formation of a (NH{sub 4}){sub 2}SiF{sub 6} powder, which is highly soluble in water. These findings let us achieve anisotropic grooving that enables to groove mc-Si wafers locally and in depth using an adequate anti-acid mask. The CVE - based grooving technique was used to form buried metallic contacts on the rear and frontal surface of the Si wafer in order to improve the current collection in mc-Si solar cells. No alteration of the spectral response in the long wavelength range was observed in mc-Si cells with rear-buried contacts. Adjustments of theoretical spectral responses to experimental ones show an increase in the effective electron diffusion length (Ln), which was attributed to Al gettering (passivation) at grain boundaries and to the reduction of the effective thickness of the base of the cells. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Single crystalline ZnO radial homojunction light-emitting diodes fabricated by metalorganic chemical vapour deposition

    Science.gov (United States)

    Yoo, Jinkyoung; Ahmed, Towfiq; Tang, Wei; Kim, Yong-Jin; Hong, Young Joon; Lee, Chul-Ho; Yi, Gyu-Chul

    2017-09-01

    ZnO radial p-n junction architecture has the potential for forward-leap of light-emitting diode (LED) technology in terms of higher efficacy and economical production. We report on ZnO radial p-n junction-based light emitting diodes prepared by full metalorganic chemical vapour deposition (MOCVD) with hydrogen-assisted p-type doping approach. The p-type ZnO(P) thin films were prepared by MOCVD with the precursors of dimethylzinc, tert-butanol, and tertiarybutylphosphine. Controlling the precursor flow for dopant results in the systematic change of doping concentration, Hall mobility, and electrical conductivity. Moreover, the approach of hydrogen-assisted phosphorous doping in ZnO expands the understanding of doping behaviour in ZnO. Ultraviolet and visible electroluminescence of ZnO radial p-n junction was demonstrated through a combination of position-controlled nano/microwire and crystalline p-type ZnO(P) radial shell growth on the wires. The reported research opens a pathway of realisation of production-compatible ZnO p-n junction LEDs.

  14. Preparation of carbon nanotubes with different morphology by microwave plasma enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan); Mansurov, Zulkhair [Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Tokmoldin, S.Zh. [Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan)

    2010-04-15

    In this work we present a part of our results about the preparation of carbon nanotube with different morphologies by using microwave plasma enhanced chemical vapour deposition MPECVD. Well aligned, curly, carbon nanosheets, coiled carbon sheets and carbon microcoils have been prepared. We have investigated the effect of the different growth condition parameters such as the growth temperature, pressure and the hydrogen to methane flow rate ratio on the morphology of the carbon nanotubes. The results showed that there is a great dependence of the morphology of carbon nanotubes on these parameters. The yield of the carbon microcoils was high when the growth temperature was 700 C. There is a linear relation between the growth rate and the methane to hydrogen ratio. The effect of the gas pressure on the CNTs was also studied. Our samples were investigated by scanning electron microscope and Raman spectroscopy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Magnetic and cytotoxic properties of hot-filament chemical vapour deposited diamond

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, Hudson, E-mail: hudsonzanin@gmail.com [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil); Peterlevitz, Alfredo Carlos; Ceragioli, Helder Jose [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil); Rodrigues, Ana Amelia; Belangero, William Dias [Laboratorio de Biomateriais em Ortopedia, Faculdade de Ciencias Medicas, Universidade Estadual de Campinas, Rua Cinco de Junho 350 CEP 13083970, Campinas, Sao Paulo (Brazil); Baranauskas, Vitor [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil)

    2012-12-01

    Microcrystalline (MCD) and nanocrystalline (NCD) magnetic diamond samples were produced by hot-filament chemical vapour deposition (HFCVD) on AISI 316 substrates. Energy Dispersive X-ray Spectroscopy (EDS) measurements indicated the presence of Fe, Cr and Ni in the MCD and NCD samples, and all samples showed similar magnetisation properties. Cell viability tests were realised using Vero cells, a type of fibroblastic cell line. Polystyrene was used as a negative control for toxicity (NCT). The cells were cultured under standard cell culture conditions. The proliferation indicated that these magnetic diamond samples were not cytotoxic. - Highlights: Black-Right-Pointing-Pointer Polycrystalline diamonds doped with Fe, Cr and Ni acquire ferromagnetic properties. Black-Right-Pointing-Pointer CVD diamonds have been prepared with magnetic and semiconductor properties. Black-Right-Pointing-Pointer Micro/nanocrystalline diamonds show good cell viability with fibroblast proliferation.

  16. Chemical vapour deposition of tungsten and tungsten silicide layers for applications in novel silicon technology

    CERN Document Server

    Li, F X

    2002-01-01

    This work was a detailed investigation into the Chemical Vapour Deposition (CVD) of tungsten and tungsten silicide for potential applications in integrated circuit (IC) and other microelectronic devices. These materials may find novel applications in contact schemes for transistors in advanced ICs, buried high conductivity layers in novel Silicon-On-Insulator (SOI) technology and in power electronic devices. The CVD techniques developed may also be used for metal coating of recessed or enclosed features which may occur in novel electronic or electromechanical devices. CVD of tungsten was investigated using the silicon reduction reaction of WF sub 6. W layers with an optimum self-limiting thickness of 100 nm and resistivity 20 mu OMEGA centre dot cm were produced self-aligned to silicon. A hydrogen passivation technique was developed as part of the wafer pre-clean schedule and proved essential in achieving optimum layer thickness. Layers produced by this approach are ideal for intimate contact to shallow junct...

  17. Microwave plasma-enhanced chemical vapour deposition growth of carbon nanostructures

    Directory of Open Access Journals (Sweden)

    Shivan R. Singh

    2010-05-01

    Full Text Available The effect of various input parameters on the production of carbon nanostructures using a simple microwave plasma-enhanced chemical vapour deposition technique has been investigated. The technique utilises a conventional microwave oven as the microwave energy source. The developed apparatus is inexpensive and easy to install and is suitable for use as a carbon nanostructure source for potential laboratory-based research of the bulk properties of carbon nanostructures. A result of this investigation is the reproducibility of specific nanostructures with the variation of input parameters, such as carbon-containing precursor and support gas flow rate. It was shown that the yield and quality of the carbon products is directly controlled by input parameters. Transmission electron microscopy and scanning electron microscopy were used to analyse the carbon products; these were found to be amorphous, nanotubes and onion-like nanostructures.

  18. Synthesis of low leakage current chemical vapour deposited (CVD) diamond films for particle detection

    Science.gov (United States)

    Bacci, T.; Borchi, E.; Bruzzi, M.; Meier, D.; Santoro, M.; Sciortino, S.

    1998-02-01

    We report on synthesis of diamond films by direct current glow discharge chemical vapour deposition (CVD) prepared at different deposition conditions, for application in high energy physics. The syntesis apparatus is briefly described. Continuous undoped diamond samples have been grown onto Mo substrates with a deposition area up to 1 cm 2 and an electrical resistivity as high as 10 13 Ωcm. The deposition parameters are related to the material properties of the diamonds, investigated by optical spectroscopy, electron microscopy and diffraction analysis. Decreasing the linear growth rate results in good quality films with small remnants of graphite-like phases. The high crystalline quality and phase purity of the films are related to very low values of leakage currents. The particle induced conductivity of these samples is also studied and preliminary results on charge collection efficiency are presented.

  19. Graphene growth from reduced graphene oxide by chemical vapour deposition: seeded growth accompanied by restoration

    Science.gov (United States)

    Chang, Sung-Jin; Hyun, Moon Seop; Myung, Sung; Kang, Min-A.; Yoo, Jung Ho; Lee, Kyoung G.; Choi, Bong Gill; Cho, Youngji; Lee, Gaehang; Park, Tae Jung

    2016-03-01

    Understanding the underlying mechanisms involved in graphene growth via chemical vapour deposition (CVD) is critical for precise control of the characteristics of graphene. Despite much effort, the actual processes behind graphene synthesis still remain to be elucidated in a large number of aspects. Herein, we report the evolution of graphene properties during in-plane growth of graphene from reduced graphene oxide (RGO) on copper (Cu) via methane CVD. While graphene is laterally grown from RGO flakes on Cu foils up to a few hundred nanometres during CVD process, it shows appreciable improvement in structural quality. The monotonous enhancement of the structural quality of the graphene with increasing length of the graphene growth from RGO suggests that seeded CVD growth of graphene from RGO on Cu surface is accompanied by the restoration of graphitic structure. The finding provides insight into graphene growth and defect reconstruction useful for the production of tailored carbon nanostructures with required properties.

  20. Diamond growth by microwave plasma enhanced chemical vapour deposition: Optical emission characterisation and effect argon addition

    Science.gov (United States)

    Mortet, V.; Hubicka, Z.; Vorlicek, V.; Jurek, K.; Rosa, J.; Vanecek, M.

    2004-09-01

    Diamond thin films were grown in an ellipsoidal 6 kWatt microwave plasma chemical vapour deposition reactor [1, 2] in a pressure range of 150 to 250 mbar. Effect of total pressure, methane concentration and argon concentration on diamond growth on mechanically seeded silicon substrates and on plasma characteristics were investigated. Optically good thick diamond films were obtained with high growth rate (4.5 m/h) at high-pressure. The argon concentration affects strongly the deposition rate, the surface morphology and the grain size. The microwave plasma was characterized by optical emission spectroscopy (OES) during deposition. Diamond films were characterized by Raman Spectroscopy and Scanning Electron Microscopy (SEM). The temperatures of the excited CH and C2 species, as well as the excitation temperature were determined from the OES measurements. The plasma composition is sensitive to the methane concentration and especially to the argon concentration in the discharge.

  1. Translation Effects in Fluorine Doped Tin Oxide Thin Film Properties by Atmospheric Pressure Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Mohammad Afzaal

    2016-10-01

    Full Text Available In this work, the impact of translation rates in fluorine doped tin oxide (FTO thin films using atmospheric pressure chemical vapour deposition (APCVD were studied. We demonstrated that by adjusting the translation speeds of the susceptor, the growth rates of the FTO films varied and hence many of the film properties were modified. X-ray powder diffraction showed an increased preferred orientation along the (200 plane at higher translation rates, although with no actual change in the particle sizes. A reduction in dopant level resulted in decreased particle sizes and a much greater degree of (200 preferred orientation. For low dopant concentration levels, atomic force microscope (AFM studies showed a reduction in roughness (and lower optical haze with increased translation rate and decreased growth rates. Electrical measurements concluded that the resistivity, carrier concentration, and mobility of films were dependent on the level of fluorine dopant, the translation rate and hence the growth rates of the deposited films.

  2. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  3. A novel three-jet microreactor for localized metal-organic chemical vapour deposition of gallium arsenide : Design and simulation

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.

    2016-01-01

    We present a novel three-jet microreactor design for localized deposition of gallium arsenide (GaAs) by low-pressure Metal-Organic Chemical Vapour Deposition (MOCVD) for semiconductor devices, microelectronics and solar cells. Our approach is advantageous compared to the standard lithography and

  4. Probing the Gas-Phase Dynamics of Graphene Chemical Vapour Deposition using in-situ UV Absorption Spectroscopy

    DEFF Research Database (Denmark)

    Shivayogimath, Abhay; Mackenzie, David; Luo, Birong

    2017-01-01

    The processes governing multilayer nucleation in the chemical vapour deposition (CVD) of graphene are important for obtaining high-quality monolayer sheets, but remain poorly understood. Here we show that higher-order carbon species in the gas-phase play a major role in multilayer nucleation...

  5. Corrosion resistant coatings (Al@#2@#O@#3@#) produced by metal-organic chemical vapour deposition using ATSB

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1993-01-01

    The metal organic chemical vapour deposition (MOCVD) of amorphous alumina films on steel was performed in nitrogen at atmospheric pressure. This MOCVD process is based on the thermal decomposition of aluminium-tri-sec-butoxide (ATSB). The effect of the deposition temperature (within the range

  6. Use of calcination in exposing the entrapped Fe particles from multi-walled carbon nanotubes grown by chemical vapour deposition

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2009-03-01

    Full Text Available Multi-walled carbon nanotubes (MWCNTs) were synthesized by a chemical vapour deposition method. The effect of calcination at temperatures ranging from 300 to 550°C in exposing the metal nanoparticles within the nanotube bundles was studied...

  7. Al2O3 coatings against high temperature corrosion deposited by metal-organic low pressure chemical vapour deposition

    NARCIS (Netherlands)

    van Corbach, H.D.; Haanappel, V.A.C.; Haanappel, V.A.C.; Fransen, T.; Gellings, P.J.

    1994-01-01

    Metal-organic chemical vapour deposition of thin amorphous films of Al2O3 on steels was performed at low pressure. Aluminium tri-sec-butoxide (ATSB) was used as a precursor. The effects of the deposition temperature (200–380 °C), the deposition pressure (0.17–1.20 kPa) and the ATSB concentration

  8. Synthesis of Tin Nitride Sn x N y Nanowires by Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Othonos Andreas

    2009-01-01

    Full Text Available Abstract Tin nitride (Sn x N y nanowires have been grown for the first time by chemical vapour deposition on n-type Si(111 and in particular by nitridation of Sn containing NH4Cl at 450 °C under a steady flow of NH3. The Sn x N y nanowires have an average diameter of 200 nm and lengths ≥5 μm and were grown on Si(111 coated with a few nm’s of Au. Nitridation of Sn alone, under a flow of NH3is not effective and leads to the deposition of Sn droplets on the Au/Si(111 surface which impedes one-dimensional growth over a wide temperature range i.e. 300–800 °C. This was overcome by the addition of ammonium chloride (NH4Cl which undergoes sublimation at 338 °C thereby releasing NH3and HCl which act as dispersants thereby enhancing the vapour pressure of Sn and the one-dimensional growth of Sn x N y nanowires. In addition to the action of dispersion, Sn reacts with HCl giving SnCl2which in turn reacts with NH3leading to the formation of Sn x N y NWs. A first estimate of the band-gap of the Sn x N y nanowires grown on Si(111 was obtained from optical reflection measurements and found to be ≈2.6 eV. Finally, intricate assemblies of nanowires were also obtained at lower growth temperatures.

  9. Evaluation of freestanding boron-doped diamond grown by chemical vapour deposition as substrates for vertical power electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Issaoui, R.; Achard, J.; Tallaire, A.; Silva, F.; Gicquel, A. [LSPM-CNRS (formerly LIMHP), Universite Paris 13, 99, Avenue Jean-Baptiste Clement, 93430 Villetaneuse (France); Bisaro, R.; Servet, B.; Garry, G. [Thales Research and Technology France, Campus de Polytechnique, 1 Avenue Augustin Fresnel, F-91767 Palaiseau Cedex (France); Barjon, J. [GEMaC-CNRS, Universite de Versailles Saint Quentin Batiment Fermat, 45 Avenue des Etats-Unis, 78035 Versailles Cedex (France)

    2012-03-19

    In this study, 4 x 4 mm{sup 2} freestanding boron-doped diamond single crystals with thickness up to 260 {mu}m have been fabricated by plasma assisted chemical vapour deposition. The boron concentrations measured by secondary ion mass spectroscopy were 10{sup 18} to 10{sup 20} cm{sup -3} which is in a good agreement with the values calculated from Fourier transform infrared spectroscopy analysis, thus indicating that almost all incorporated boron is electrically active. The dependence of lattice parameters and crystal mosaicity on boron concentrations have also been extracted from high resolution x-ray diffraction experiments on (004) planes. The widths of x-ray rocking curves have globally shown the high quality of the material despite a substantial broadening of the peak, indicating a decrease of structural quality with increasing boron doping levels. Finally, the suitability of these crystals for the development of vertical power electronic devices has been confirmed by four-point probe measurements from which electrical resistivities as low as 0.26 {Omega} cm have been obtained.

  10. Methods for estimating the vapour pressure of organic chemicals; Application to five pesticides

    NARCIS (Netherlands)

    Leistra, M.

    2011-01-01

    When studying and modelling the volatilisation of pesticides from crops, their vapour pressure is an essential property. In the critical evaluation of vapour pressures stated by various sources, problems were encountered. Therefore, an inventory was made of readily-usable methods for estimating

  11. Expanding Thermal Plasma Chemical Vapour Deposition of ZnO:Al Layers for CIGS Solar Cells

    Directory of Open Access Journals (Sweden)

    K. Sharma

    2014-01-01

    Full Text Available Aluminium-doped zinc oxide (ZnO:Al grown by expanding thermal plasma chemical vapour deposition (ETP-CVD has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO. In this paper, the potential of adopting ETP-CVD ZnO:Al in CIGS solar cells is assessed: the effect of substrate temperature during film deposition on both the electrical properties of the ZnO:Al and the eventual performance of the CIGS solar cells was investigated. For ZnO:Al films grown using the high thermal budget (HTB condition, lower resistivities, ρ, were achievable (~5 × 10−4 Ω·cm than those grown using the low thermal budget (LTB conditions (~2 × 10−3 Ω·cm, whereas higher CIGS conversion efficiencies were obtained for the LTB condition (up to 10.9% than for the HTB condition (up to 9.0%. Whereas such temperature-dependence of CIGS device parameters has previously been linked with chemical migration between individual layers, we demonstrate that in this case it is primarily attributed to the prevalence of shunt currents.

  12. Chemical Selectivity and Sensitivity of a 16-Channel Electronic Nose for Trace Vapour Detection

    Directory of Open Access Journals (Sweden)

    Drago Strle

    2017-12-01

    Full Text Available Good chemical selectivity of sensors for detecting vapour traces of targeted molecules is vital to reliable detection systems for explosives and other harmful materials. We present the design, construction and measurements of the electronic response of a 16 channel electronic nose based on 16 differential microcapacitors, which were surface-functionalized by different silanes. The e-nose detects less than 1 molecule of TNT out of 10+12 N2 molecules in a carrier gas in 1 s. Differently silanized sensors give different responses to different molecules. Electronic responses are presented for TNT, RDX, DNT, H2S, HCN, FeS, NH3, propane, methanol, acetone, ethanol, methane, toluene and water. We consider the number density of these molecules and find that silane surfaces show extreme affinity for attracting molecules of TNT, DNT and RDX. The probability to bind these molecules and form a surface-adsorbate is typically 10+7 times larger than the probability to bind water molecules, for example. We present a matrix of responses of differently functionalized microcapacitors and we propose that chemical selectivity of multichannel e-nose could be enhanced by using artificial intelligence deep learning methods.

  13. Fluorinated carboxylic membranes deposited by plasma enhanced chemical vapour deposition for fuel cell applications

    Science.gov (United States)

    Thery, J.; Martin, S.; Faucheux, V.; Le Van Jodin, L.; Truffier-Boutry, D.; Martinent, A.; Laurent, J.-Y.

    Among the fuel cell technologies, the polymer electrolyte membrane fuel cells (PEMFCs) are particularly promising because they are energy-efficient, clean, and fuel-flexible (i.e., can use hydrogen or methanol). The great majority of PEM fuel cells rely on a polymer electrolyte from the family of perfluorosulfonic acid membranes, nevertheless alternative materials are currently being developed, mainly to offer the alternative workout techniques which are required for the portable energy sources. Plasma polymerization represents a good solution, as it offers the possibility to deposit thin layer with an accurate and homogeneous thickness, even on 3D surfaces. In this paper, we present the results for the growth of proton conductive fluoro carboxylic membranes elaborated by plasma enhanced chemical vapour deposition. These membranes present conductivity values of the same order than the one of Nafion ®. The properties of the membrane, such as the chemical composition, the ionic conductivity, the swelling behaviour and the permeability were correlated to the plasma process parameters. The membranes were integrated in fuel cells on porous substrates and we present here the results regarding the barrier effect and the power output. Barrier effect similar to those of 40 μm Nafion ® layers was reached for 10 μm thick carboxylic membranes. Power outputs around 3 mW cm -2 were measured. We discuss the results regarding the gas barrier effect and the power outputs.

  14. Synthesis of few layer single crystal graphene grains on platinum by chemical vapour deposition

    Directory of Open Access Journals (Sweden)

    S. Karamat

    2015-08-01

    Full Text Available The present competition of graphene electronics demands an efficient route which produces high quality and large area graphene. Chemical vapour deposition technique, where hydrocarbons dissociate in to active carbon species and form graphene layer on the desired metal catalyst via nucleation is considered as the most suitable method. In this study, single layer graphene with the presence of few layer single crystal graphene grains were grown on Pt foil via chemical vapour deposition. The higher growth temperature changes the surface morphology of the Pt foil so a delicate process of hydrogen bubbling was used to peel off graphene from Pt foil samples with the mechanical support of photoresist and further transferred to SiO2/Si substrates for analysis. Optical microscopy of the graphene transferred samples showed the regions of single layer along with different oriented graphene domains. Two type of interlayer stacking sequences, Bernal and twisted, were observed in the graphene grains. The presence of different stacking sequences in the graphene layers influence the electronic and optical properties; in Bernal stacking the band gap can be tunable and in twisted stacking the overall sheet resistance can be reduced. Grain boundaries of Pt provides low energy sites to the carbon species, therefore the nucleation of grains are more at the boundaries. The stacking order and the number of layers in grains were seen more clearly with scanning electron microscopy. Raman spectroscopy showed high quality graphene samples due to very small D peak. 2D Raman peak for single layer graphene showed full width half maximum (FWHM value of 30 cm−1. At points A, B and C, Bernal stacked grain showed FWHM values of 51.22, 58.45 and 64.72 cm−1, while twisted stacked grain showed the FWHM values of 27.26, 28.83 and 20.99 cm−1, respectively. FWHM values of 2D peak of Bernal stacked grain showed an increase of 20–30 cm−1 as compare to single layer graphene

  15. Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

    CERN Document Server

    Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

    2002-01-01

    The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

  16. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

  17. Continuous production of carbon nanotubes and diamond films by swirled floating catalyst chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    S.E. Iyuke

    2010-01-01

    Full Text Available Various techniques for the synthesis of carbon nanotubes (CNTs are being developed to meet an increasing demand as a result of their versatile applications. Swirled floating catalyst chemical vapour deposition (SFCCVD is one of these techniques. This method was used to synthesise CNTs on a continuous basis using acetylene gas as a carbon source, ferrocene dissolved in xylene as a catalyst precursor, and both hydrogen and argon as carrier gases. Transmission electron microscopy analyses revealed that a mixture of single and multi-wall carbon nanotubes and other carbon nanomaterials were produced within the pyrolytic temperature range of 900–1 100°C and acetylene flow rate range of 118–370 ml min–1. Image comparison of raw and purified products showed that low contents of iron particles and amorphous carbon were contained in the synthesised carbon nanotubes. Diamond films were produced at high ferrocene concentration, hydrogen flow rate and pyrolysis temperatures, while carbon nanoballs were formed and attached to the surface of theCNTs at low ferrocene content and low pyrolysis temperature.

  18. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Science.gov (United States)

    Jagdale, Pravin; Castellino, Micaela; Marrec, Françoise; Rodil, Sandra E.; Tagliaferro, Alberto

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl3) in acetone (CH3sbnd COsbnd CH3). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18-250 nm thick and a few micrometres wide.

  19. Functionalization of Hydrogenated Chemical Vapour Deposition-Grown Graphene by On-Surface Chemical Reactions

    Czech Academy of Sciences Publication Activity Database

    Drogowska, Karolina; Kovaříček, Petr; Kalbáč, Martin

    2017-01-01

    Roč. 23, č. 17 (2017), s. 4022-4022 ISSN 1521-3765 Institutional support: RVO:61388955 Keywords : Chemical vapor deposition * Hydrogenation * Graphene Subject RIV: CF - Physical ; Theoretical Chemistry

  20. SiCN alloys obtained by remote plasma chemical vapour deposition from novel precursors

    Energy Technology Data Exchange (ETDEWEB)

    Smirnova, T.P.; Badalian, A.M.; Yakovkina, L.V.; Kaichev, V.V.; Bukhtiyarov, V.I.; Shmakov, A.N.; Asanov, I.P.; Rachlin, V.I.; Fomina, A.N

    2003-04-01

    Silicon carbonitride films were synthesised in a remote plasma chemical vapour deposition process using novel single-source precursors [(CH{sub 3}){sub 2}HSiNHN(CH{sub 3}){sub 2} and (CH{sub 3}){sub 2}Si[NHN(CH{sub 3}){sub 2}]{sub 2}, which are silyl derivatives of 1,1-dimethylhydrazine. The films were characterised by X-ray photoelectron (XPS), Fourier transform infrared (FTIR) and UV-Vis absorption spectroscopy. The microstructure of the films was examined by scanning electron microscopy and diffraction of synchrotron radiation methods. XPS and FTIR spectroscopic studies showed the Si-C and Si-N to be the basic bonds for the films deposited in the system with excited hydrogen, whereas the C-N and Si-N bonds are mainly peculiar to the films synthesised in the system with excited helium. The films were found to be predominately amorphous with a number of crystallites embedded in an unstructured matrix. The crystalline phase can be indexed in tetragonal cell with lattice parameters a=9.6 A and c=6.4 A. Appearance of the crystals, their dimensions and crystal forms did not depend on the substrate temperature. We hypothesised the crystallisation to be occurring either in the gas phase during deposition or in the solid as a result of the increase in mechanical stress with increasing film thickness. The FTIR and XPS data demonstrate the chemical bonding and the atomic local order in the amorphous matrix to be much more complicated than those of Si{sub 3}N{sub 4}-SiC or Si{sub 3}N{sub 4}-C{sub 3}N{sub 4} mixtures. This novel material has an optical band gap varying within the energy range from 2.0 to 4.7 eV. The films obtained were highly resistant to thermal degradation.

  1. Structural Properties of ZnO/SnO2-Composite-Nanorod Deposited Using Thermal Chemical Vapour Deposition

    Science.gov (United States)

    Sin, N. D. Md; Shafura, A. K.; Malek, M. F.; Mamat, M. H.; Rusop, M.

    2015-05-01

    In this work, we report on the effect of substrate temperatures on ZnO/SnO2 composite nanorods deposited by thermal chemical vapour deposition (CVD) onto a ZnO template layer. The substrate temperature varied from 200 ∼ 600°C. The FESEM image reveals that the size of the thin film created by the ZnO/SnO2 composite nanorods decreased as the substrate temperature increased.

  2. Integration of metal organic chemical vapour deposition and wet chemical techniques to obtain highly ordered porous ZnO nanoplatforms.

    Science.gov (United States)

    Fragalà, Maria Elena; Aleeva, Yana; Satriano, Cristina

    2011-09-01

    Large-area, highly ordered ZnO micropores-arrays consisting of ZnO nanotubes delimited by ZnO nanorods have been successfully fabricated and tested for protein sensing applications. ZnO seed layers have been deposited by Metal Organic Chemical Vapour Deposition and readily patterned by Colloidal Lithography to attain ZnO nanorods growth at selective sites by Chemical Bath Deposition. The used synthetic approach has been proven effective for the easy assembly of ZnO nanoplatforms into high-density arrays. Both patterned and unpatterned ZnO nanorods have been morphologically and compositionally characterised and, thus, tested for model studies of protein mobility at the interface. The patterned layers, having a higher contribution of surface polar moieties than the corresponding unpatterned surfaces, exhibit a reduced lateral diffusion of the adsorbed protein. This evidence is related to the intrinsic porous nature of the ZnO hemispherical arrays characterised by a nanotube-nanorod hybrid networks. The present study gives a great impetus to the fabrication of tunable ZnO nanoplatforms having multiple morphologies and exceptionally high surface areas suitable for application in sensing devices.

  3. Structural evolution of a Ta-filament during hot-wire chemical vapour deposition of Silicon investigated by electron backscatter diffraction

    CSIR Research Space (South Africa)

    Oliphant, CJ

    2012-03-01

    Full Text Available In this study we investigate the structural changes of a burnt-out tantalum filament that was operated at typical hydrogenated nanocrystalline silicon synthesis conditions in our hot-wire chemical vapour deposition chamber. Scanning electron...

  4. Conductive zinc oxide thin film coatings by combustion chemical vapour deposition at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zunke, I., E-mail: iz@innovent-jena.de [Innovent e.V. Technology Development, Department of Surface Engineering, Prüssingstr. 27B, 07745 Jena (Germany); Heft, A. [Innovent e.V. Technology Development, Department of Surface Engineering, Prüssingstr. 27B, 07745 Jena (Germany); Schäfer, P.; Haidu, F.; Lehmann, D. [Chemnitz University of Technology, Semiconductor Physics, Reichenhainer Str. 70, 09126 Chemnitz (Germany); Grünler, B.; Schimanski, A. [Innovent e.V. Technology Development, Department of Surface Engineering, Prüssingstr. 27B, 07745 Jena (Germany); Zahn, D.R.T. [Chemnitz University of Technology, Semiconductor Physics, Reichenhainer Str. 70, 09126 Chemnitz (Germany)

    2013-04-01

    We have established a combustion chemical vapour deposition (C-CVD) system for the deposition of zinc oxide (ZnO) at atmospheric pressure. This C-CVD process has the advantage of a short exposure of the substrates to the flame. It is also potentially applicable as an inline coating system. Fundamental studies were performed on undoped ZnO. The specific resistivity of these layers strongly depends on the film thickness and decreases with increasing thickness. As the lowest resistivities, values of about 2.0 · 10{sup −1} Ωcm are achieved. Ultra-violet photoemission spectra show the valence band structure of the deposited ZnO. The work function and valence band edge were determined. UV–vis spectra were taken to investigate the transmission of the coated glass samples. From these spectra the band gap energy was obtained. Raman spectroscopy as well as infrared spectroscopy confirmed the presence of ordered ZnO crystallites. The X-ray diffraction verified this result and illustrates the hexagonal structure. In the mid-infrared range precursor deposits were detected for low substrate temperatures. - Highlights: ► Zinc oxide (ZnO) films are conductive in the range of 2.0 · 10{sup −1} Ωcm. ► X-ray diffraction, Raman and infrared spectroscopy indicate crystalline ZnO films. ► Precursor deposits were proved within the films for low growing temperatures. ► Band gap energy changes are achieved due to different growing temperatures.

  5. Growth of Au-catalysed Si nanowires by low pressure chemical vapour deposition on Si(100) and amorphous Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Santoni, A; Villacorta, F Jimenez; Rufoloni, A; Mancini, A [ENEA C.R. Frascati, v. E. Fermi 45, I-00044 Frascati (Italy)

    2006-12-06

    Au-mediated Si nanowires (SiNW) have been grown at low temperatures (500-560 {sup 0}C) on crystalline Si(100) and amorphous Si surfaces by means of low pressure chemical vapour deposition from Si{sub 2}H{sub 6} in the 0.05-1.2 mbar range. The influence of the substrates on the nanowire (NW) growth and morphology has been investigated by means of x-ray photoelectron spectroscopy and scanning electron microscopy. No NW growth has been observed on the Au covered amorphous Si surfaces. On both substrates, the NW exhibit inhomogeneous sidewalls and a new morphology showing NW entrenchment which has been explained as a consequence of vapour-liquid-solid growth termination due to Au diffusion on the SiNW sidewalls.

  6. Chemically Assisted Photocatalytic Oxidation System

    Science.gov (United States)

    Andino, Jean; Wu, Chang-Yu; Mazyck, David; Teixeira, Arthur A.

    2009-01-01

    The chemically assisted photocatalytic oxidation system (CAPOS) has been proposed for destroying microorganisms and organic chemicals that may be suspended in the air or present on surfaces of an air-handling system that ventilates an indoor environment. The CAPOS would comprise an upstream and a downstream stage that would implement a tandem combination of two partly redundant treatments. In the upstream stage, the air stream and, optionally, surfaces of the air-handling system would be treated with ozone, which would be generated from oxygen in the air by means of an electrical discharge or ultraviolet light. In the second stage, the air laden with ozone and oxidation products from the first stage would be made to flow in contact with a silica-titania photocatalyst exposed to ultraviolet light in the presence of water vapor. Hydroxyl radicals generated by the photocatalytic action would react with both carbon containing chemicals and microorganisms to eventually produce water and carbon dioxide, and ozone from the first stage would be photocatalytically degraded to O2. The net products of the two-stage treatment would be H2O, CO2, and O2.

  7. The study and the realization of radiation detectors made from polycrystalline diamond films grown by microwave plasma enhanced chemical vapour deposition technique; Etude et realisation de detecteurs de rayonnements a base de films de diamant polycristallin elabores par depot chimique en phase vapeur assiste par plasma micro-onde

    Energy Technology Data Exchange (ETDEWEB)

    Jany, Ch

    1998-10-29

    The aim of this work was to develop radiation detectors made from polycrystalline diamond films grown by microwave plasma enhanced chemical vapour deposition technique. The influence of surface treatments, contact technology and diamond growth parameters on the diamond detectors characteristics was investigated in order to optimise the detector response to alpha particles. The first part of the study focused on the electrical behaviour of as-deposited diamond surface, showing a p type conduction and its influence on the leakage current of the device. A surface preparation process was established in order to reduce the leakage current of the device by surface dehydrogenation using an oxidising step. Several methods to form and treat electrical contacts were also investigated showing that the collection efficiency of the device decreases after contact annealing. In the second part, we reported the influence of the diamond deposition parameters on the characteristics of the detectors. The increase of the deposition temperature and/or methane concentration was shown to lead {eta} to decrease. In contrast, {eta} was found to increase with the micro-wave power. The evolution of the diamond detector characteristics results from the variation in sp{sup 2} phases incorporation and in the crystallography quality of the films. These defects increase the leakage current and reduce the carrier mobility and lifetime. Measurements carried out on detectors with different thicknesses showed that the physical properties varies along the growth direction, improving with the film thickness. Finally, the addition of nitrogen (> 10 ppm) in the gas mixture during diamond deposition was found to strongly reduce the collection efficiency of the detectors. To conclude the study, we fabricated and characterised diamond devices which were used for thermal neutron detection and for the intensity and shape measurement of VUV and soft X-ray pulses. (author)

  8. Doped zinc oxide films grown by hot-wire chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Abrutis, A., E-mail: adulfas.abrutis@chf.vu.lt; Silimavicius, L.; Kubilius, V.; Murauskas, T.; Saltyte, Z.; Plausinaitiene, V.

    2015-02-02

    Hot-wire chemical vapour deposition (CVD) was applied to grow zinc oxide (ZnO)-based transparent conducting oxide films. Indium (In)-, gallium (Ga)-, and aluminium (Al)-doped ZnO films were deposited at 400 °C on sapphire-R, Si (100) and glass substrates using a cold wall pulsed liquid injection CVD system containing nichrome wires installed in front of the substrate holder. Zn, In, Al 2,2,6,6-tetramethyl-3,5-heptanedionates, and Ga 3,5-pentanedionate dissolved in 1,2-dimethoxyethane were used as precursors. Hall measurements were performed to evaluate the resistivity, carrier concentration, and carrier mobility in doped ZnO films grown on sapphire substrates at wire currents of 6 A and 9 A. The influence of the dopant type, doping level, substrate, and wire heating current on crystallinity and the electrical and optical properties of the films was investigated and discussed. The best electrical properties were obtained for Al- and Ga-doped films grown at 9 A wire current (resistivity ≈ 1 × 10{sup −3} Ωcm, carrier mobility ≈ 50 cm{sup 2} V{sup −1} s{sup −1} and carrier concentration ≈ 1 × 10{sup 20} cm{sup −3}). The films exhibited a high transmittance in the mid-infrared region (≈ 90% at 2.5 μm). Additional annealing of the films at 400 °C in a mixture of Ar and hydrogen (10%) resulted in the increase in carrier concentration and mobility and in the reduction of film resistivity. - Highlights: • Hot-wire CVD process was applied for the growth of In-, Ga-, and Al-doped ZnO films. • Electrical and optical properties of as-deposited and annealed films were investigated. • Significant influence of film orientation on electrical properties was observed. • Films exhibited high carrier mobility (50–60 cm{sup 2} V{sup −1} s{sup −1}) and low resistivity (≤ 10{sup −3} Ωcm). • Films had high transmittance (~ 90%) in the mid-IR spectral range (at 2.5 μm)

  9. Development of vapour liquid equilibrium calculation methods for chemical engineering design

    OpenAIRE

    Pokki, Juha-Pekka

    2004-01-01

    This thesis deals with the development of computational methods for vapour liquid equilibrium (VLE) and volumetric properties. The VLE in this thesis can be divided into the low- and medium-pressure VLE with an experimental part and into the high-pressure VLE with a modelling and simulation part. The volumetric properties in this thesis deal with the extension of the model for compressed liquid densities. At low-pressure VLE, the emphasis was on the optimisation of model parameters. Two a...

  10. Student Assistance Guide for Chemical Dependency.

    Science.gov (United States)

    Saint Vincent Medical Center, Toledo, OH. Tennyson Center.

    This document presents practical suggestions for student assistance workers who might work with chemically dependent adolescents. It illustrates the stages of chemical dependency, discusses the progression of dependency in adolescents, and provides guidelines for identifying a chemically dependent adolescent. Since chemically dependent persons…

  11. Solvent-vapour-assisted pathways and the role of pre-organization in solid-state transformations of coordination polymers

    Directory of Open Access Journals (Sweden)

    James S. Wright

    2015-03-01

    Full Text Available A family of one-dimensional coordination polymers, [Ag4(O2C(CF22CF34(phenazine2(arenen]·m(arene, 1 (arene = toluene or xylene, have been synthesized and crystallographically characterized. Arene guest loss invokes structural transformations to yield a pair of polymorphic coordination polymers [Ag4(O2C(CF22CF34(phenazine2], 2a and/or 2b, with one- and two-dimensional architectures, respectively. The role of pre-organization of the polymer chains of 1 in the selectivity for formation of either polymorph is explored, and the templating effect of toluene and p-xylene over o-xylene or m-xylene in the formation of arene-containing architecture 1 is also demonstrated. The formation of arene-free phase 2b, not accessible in a phase-pure form through other means, is shown to be the sole product of loss of toluene from 1-tol·tol [Ag4(O2C(CF22CF34(phenazine2(toluene]·2(toluene, a phase containing toluene coordinated to Ag(I in an unusual μ:η1,η1 manner. Solvent-vapour-assisted conversion between the polymorphic coordination polymers and solvent-vapour influence on the conversion of coordination polymers 1 to 2a and 2b is also explored. The transformations have been examined and confirmed by X-ray diffraction, NMR spectroscopy and thermal analyses, including in situ diffraction studies of some transformations.

  12. Preliminary viability studies of fibroblastic cells cultured on microcrystalline and nanocrystalline diamonds produced by chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    Ana Amélia Rodrigues

    2013-02-01

    Full Text Available Implant materials used in orthopedics surgery have demonstrated some disadvantages, such as metallic corrosion processes, generation of wear particles, inflammation reactions and bone reabsorption in the implant region. The diamond produced through hot-filament chemical vapour deposition method is a new potential biomedical material due to its chemical inertness, extreme hardness and low coefficient of friction. In the present study we analysis two samples: the microcrystalline diamond and the nanocrystalline diamond. The aim of this study was to evaluate the surface properties of the diamond samples by scanning electron microscopy, Raman spectroscopy and atomic force microscopy. Cell viability and morphology were assessed using thiazolyl blue tetrazolium bromide, cytochemical assay and scanning electron microscopy, respectively. The results revealed that the two samples did not interfere in the cell viability, however the proliferation of fibroblasts cells observed was comparatively higher with the nanocrystalline diamond.

  13. Preliminary viability studies of fibroblastic cells cultured on microcrystalline and nanocrystalline diamonds produced by chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    Ana Amélia Rodrigues

    2012-01-01

    Full Text Available Implant materials used in orthopedics surgery have demonstrated some disadvantages, such as metallic corrosion processes, generation of wear particles, inflammation reactions and bone reabsorption in the implant region. The diamond produced through hot-filament chemical vapour deposition method is a new potential biomedical material due to its chemical inertness, extreme hardness and low coefficient of friction. In the present study we analysis two samples: the microcrystalline diamond and the nanocrystalline diamond. The aim of this study was to evaluate the surface properties of the diamond samples by scanning electron microscopy, Raman spectroscopy and atomic force microscopy. Cell viability and morphology were assessed using thiazolyl blue tetrazolium bromide, cytochemical assay and scanning electron microscopy, respectively. The results revealed that the two samples did not interfere in the cell viability, however the proliferation of fibroblasts cells observed was comparatively higher with the nanocrystalline diamond.

  14. Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

    Directory of Open Access Journals (Sweden)

    Malik Anushree

    2010-11-01

    Full Text Available Abstract Background Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Methods Minimum Inhibitory concentration (MIC of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM/Atomic force microscopy (AFM and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Results Lemon grass (Cymbopogon citratus essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita and eucalyptus (Eucalyptus globulus essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l was significantly higher than that in the vapour phase (32.7 mg/l and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%; α-citral or geranial (36.2% and β-citral or neral (26.5%, monoterpene hydrocarbons (7.9% and sesquiterpene hydrocarbons (3.8%. Conclusion Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious

  15. Liquid and vapour-phase antifungal activities of selected essential oils against Candida albicans: microscopic observations and chemical characterization of Cymbopogon citratus.

    Science.gov (United States)

    Tyagi, Amit K; Malik, Anushree

    2010-11-10

    Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell

  16. Increasing the output power of single 808-nm laser diodes using diamond submounts produced by microwave plasma chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ashkinazi, E E; Bezotosnyi, V V; Bondarev, Vadim Yu; Kovalenko, V I; Konov, Vitalii I; Krokhin, Oleg N; Oleshchenko, V A; Pevtsov, Valerii F; Popov, Yurii M; Popovich, A F; Ral' chenko, Viktor G; Cheshev, E A

    2012-11-30

    We have designed and fabricated submounts from synthetic diamond grown by microwave plasma chemical vapour deposition and developed an economical process for metallising such submounts. Laser diode chips having an 808-nm emission wavelength, 3-mm-long cavity and 130-mm-wide stripe contact were mounted on copper heat sinks with the use of diamond submounts differing in quality. The devices were tested for more than 150 h in continuous mode at an output power of 8 W on diamond with a thermal conductivity of 700 W m{sup -1} K{sup -1}, and no changes in their output power were detected. On diamond with a thermal conductivity of 1600 W m{sup -1} K{sup -1}, stable cw operation for 24 h at an output power of 12 W was demonstrated. (letters)

  17. Structural characterisation of silicon-germanium virtual substrate- based heterostructures grown by low pressure chemical vapour deposition

    CERN Document Server

    Mihai-Dilliway, G D

    2002-01-01

    Silicon-germanium heterostructures incorporating compositionally graded virtual substrates are important for the fabrication of a variety of advanced electronic devices. Their successful application depends critically on their surface morphology and defect content. The aim of this research project is to characterise the way in which these structural properties are influenced by the growth parameters used in low pressure chemical vapour deposition (LPCVD) at the Southampton University Microelectronics Centre (SUMC). To this end, a comparative study of the surface quality and the distribution and density of misfit strain relaxation induced defects in SiGe virtual substrate-based heterostructures grown under varying conditions, was carried out. The growth parameters varied have been: growth temperature, initial and final Ge content, Ge concentration gradient, type of Ge grading profile (linear and stepwise) in the virtual substrate, and thickness and presence of a device structure in the capping layer of constan...

  18. Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition

    Science.gov (United States)

    Anthony, David B.; Qian, Hui; Clancy, Adam J.; Greenhalgh, Emile S.; Bismarck, Alexander; Shaffer, Milo S. P.

    2017-07-01

    The application of an in situ potential difference between carbon fibres and a graphite foil counter electrode (300 V, generating an electric field ca 0.3-0.7 V μm-1), during the chemical vapour deposition synthesis of carbon nanotube (CNT) grafted carbon fibres, significantly improves the uniformity of growth without reducing the tensile properties of the underlying carbon fibres. Grafted CNTs with diameters 55 nm ± 36 nm and lengths around 10 μm were well attached to the carbon fibre surface, and were grown without the requirement for protective barrier coatings. The grafted CNTs increased the surface area to 185 m2 g-1 compared to the as-received sized carbon fibre 0.24 m2 g-1. The approach is not restricted to batch systems and has the potential to improve CNT grafted carbon fibre production for continuous processing.

  19. "Plasma charging damage induced by a power ramp down step in the end of plasma enhanced chemical vapour deposition (PECVD) process

    NARCIS (Netherlands)

    Wang, Zhichun; Ackaert, Jan; Salm, Cora; Kuper, F.G.; Bessemans, Klara; de Backer, Eddy

    2003-01-01

    Plasma Enhanced Chemical Vapour Deposition (PECVD) is one of the main plasma processes which induce charging damage to gate oxides during the VLSI processes. All the previous studies, however, describe the charging phenomena only at the beginning of PECVD process, when a very thin oxide layer covers

  20. The protective properties of thin alumina films deposited by metal organic chemical vapour deposition against high-temperature corrosion of stainless steels

    NARCIS (Netherlands)

    Morssinkhof, R.W.J.; Fransen, T.; Heusinkveld, M.M.D.; Gellings, P.J.

    1989-01-01

    Coatings of Al2O3 were deposited on Incoloy 800H and AISI 304 by means of metal organic chemical vapour deposition. Diffusion limitation was the rate-determining step above 420 °C. Below this temperature, the activation energy of the reaction appeared to be 30 kJ mol−1. Coating with Al2O3 increases

  1. Properties of alumina films prepared by metal-organic chemical vapour deposition at atmospheric pressure in hte presence of small amounts of water

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Rem, J.B.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films were deposited on stainless steel, type AISI 304. The deposition process was carried out in nitrogen with low partial pressures of water (0–2.6 × 10−2 kPa (0−0.20 mmHg)) by metal-organic chemical vapour deposition (MOCVD) with aluminium-tri-sec-butoxide (ATSB) as the precursor.

  2. A novel three-jet microreactor for localized metal-organic chemical vapour deposition of gallium arsenide: design and simulation

    Science.gov (United States)

    Konakov, S. A.; Krzhizhanovskaya, V. V.

    2016-08-01

    We present a novel three-jet microreactor design for localized deposition of gallium arsenide (GaAs) by low-pressure Metal-Organic Chemical Vapour Deposition (MOCVD) for semiconductor devices, microelectronics and solar cells. Our approach is advantageous compared to the standard lithography and etching technology, since it preserves the nanostructure of the deposited material, it is less time-consuming and less expensive. We designed two versions of reactor geometry with a 10-micron central microchannel for precursor supply and with two side jets of a dilutant to control the deposition area. To aid future experiments, we performed computational modeling of a simplified-geometry (twodimensional axisymmetric) microreactor, based on Navier-Stokes equations for a laminar flow of chemically reacting gas mixture of Ga(CH3)3-AsH3-H2. Simulation results show that we can achieve a high-rate deposition (over 0.3 μm/min) on a small area (less than 30 μm diameter). This technology can be used in material production for microelectronics, optoelectronics, photovoltaics, solar cells, etc.

  3. PENGARUH KATALIS Co DAN Fe TERHADAP KARAKTERISTIK CARBON NANOTUBES DARI GAS ASETILENA DENGAN MENGGUNAKAN PROSES CATALYTIC CHEMICAL VAPOUR DEPOSITION (CCVD

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2013-11-01

    Full Text Available EFFECT OF Co AND Fe ON CARBON NANOTUBES CHARACTERISTICS FROM ACETYLENE USING CATALYTIC CHEMICAL VAPOUR DEPOSITION (CCVD PROCESS. Carbon Nanotubes (CNTs is one of the most well known nano-technology applications which the most of attracting the attention of researchers, because it has more advantages than other materials. The application of the CNT has extended into various aspects, such as electronics, materials, biology and chemistry. This research uses a system of Catalytic Chemical Vapour Deposition (CCVD, which aims to determine the influence of Co and Fe as a catalyst and zeolite 4A as a support catalyst with acetylene gas (C2H2 as carbon source in the synthesis of Carbon Nanotubes (CNTs. In this experiment, used the ratio of acetylene gas and flow rate of N2 gas is 1:1 by weight of the catalyst Co/Zeolite and Fe/Zeolite amounted to 0.5 grams at the operating temperature of 700oC for 20 minutes. N2 gas serves to minimize the occurrence of oxidation reaction (explosion when operating. From analysis result by Scanning Electron Microscopy (SEM shows the CNTs formed a type of MWNT with different of diameter size and product weight, depending on the size of the active component concentration on the catalyst. The larger of active components produced CNTs with larger diameter, whereas product weight syntheses result smaller. Use of the catalyst Fe/Zeolite produce CNTs with a diameter larger than the catalyst Co/Zeolite.  Carbon Nanotubes (CNTs merupakan salah satu aplikasi nanoteknologi yang paling terkenal dan banyak menarik perhatian para peneliti, karena memiliki beberapa kelebihan daripada material lainnya. Aplikasi dari CNT telah merambah ke berbagai aspek, seperti bidang elektronika, material, biologi dan kimia. Penelitian ini menggunakan sistem Catalytic Chemical Vapour Deposition (CCVD yang bertujuan untuk mengetahui pengaruh variasi Cobalt (Co dan Ferrum (Fe sebagai katalis dan zeolit tipe 4A sebagai penyangga katalis dengan gas

  4. Biocidal Silver and Silver/Titania Composite Films Grown by Chemical Vapour Deposition

    OpenAIRE

    Sheel, DW; Brook, LA; Evans, P.; Foster, HA; Yates, HM; Steele, A; Ditta, IB

    2008-01-01

    This paper describes the growth and testing of highly active biocidal films based on photocatalytically active films of TiO2, grownby\\ud thermal CVD, functionally and structurallymodified by deposition of nanostructured silver via a novel flame assisted combination\\ud CVD process. The resulting composite films are shown to be highly durable, highly photocatalytically active and are also shown to\\ud possess strong antibacterial behaviour. The deposition control, arising from the described appr...

  5. Metal-organic chemical vapour deposition of lithium manganese oxide thin films via single solid source precursor

    Directory of Open Access Journals (Sweden)

    Oyedotun K.O.

    2015-12-01

    Full Text Available Lithium manganese oxide thin films were deposited on sodalime glass substrates by metal organic chemical vapour deposition (MOCVD technique. The films were prepared by pyrolysis of lithium manganese acetylacetonate precursor at a temperature of 420 °C with a flow rate of 2.5 dm3/min for two-hour deposition period. Rutherford backscattering spectroscopy (RBS, UV-Vis spectrophotometry, X-ray diffraction (XRD spectroscopy, atomic force microscopy (AFM and van der Pauw four point probe method were used for characterizations of the film samples. RBS studies of the films revealed fair thickness of 1112.311 (1015 atoms/cm2 and effective stoichiometric relationship of Li0.47Mn0.27O0.26. The films exhibited relatively high transmission (50 % T in the visible and NIR range, with the bandgap energy of 2.55 eV. Broad and diffused X-ray diffraction patterns obtained showed that the film was amorphous in nature, while microstructural studies indicated dense and uniformly distributed layer across the substrate. Resistivity value of 4.9 Ω·cm was obtained for the thin film. Compared with Mn0.2O0.8 thin film, a significant lattice absorption edge shift was observed in the Li0.47Mn0.27O0.26 film.

  6. Direct synthesis of solid and hollow carbon nanospheres over NaCl crystals using acetylene by chemical vapour deposition

    Science.gov (United States)

    Chandra Kishore, S.; Anandhakumar, S.; Sasidharan, M.

    2017-04-01

    Carbon nanospheres (CNS) with hollow and solid morphologies have been synthesised by a simple chemical vapour deposition method using acetylene as a carbon precursor. Sodium chloride (NaCl) powder as a template was used for the direct growth of CNS via facile and low-cost approach. The effect of various temperatures (500 °C, 600 °C and 700 °C) and acetylene flow rates were investigated to study the structural evolution on the carbon products. The purified CNS thus obtained was characterized by various physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and cyclicvoltametry. The synthesised hollow nanospheres were investigated as anode materials for Li-ion batteries. After 25 cycles of repeated charge/discharge cycles, the discharge and charge capacities were found to be 574 mAh/g and 570 mAh/g, respectively which are significantly higher than the commercial graphite samples.

  7. Catalytic Carbon Submicron Fabrication Using Home-Built Very-High Frequency Plasma Enhanced Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Sukirno

    2008-09-01

    Full Text Available In this research, carbon nanotubes (CNT fabrication is attempted by using existing home-made Plasma Enhanced Chemical Vapour Deposition (PECVD system. The fabrication is a catalytic growth process, which Fe catalyst thin film is grown on the Silicon substrate by using dc-Unbalanced Magnetron Sputtering method. By using methane (CH4 as the source of carbon and diluted silane (SiH4 in hydrogen as the source of hydrogen with 10:1 ratio, CNT fabrications have been attempted by using Very High Frequency PECVD (VHF-PECVD method. The fabrication processes are done at relatively low temperature, 250oC, but with higher operated plasma frequency, 70 MHz. Recently, it is also been attempted a fabrication process with only single gas source, but using one of the modification of the VHF-PECVD system, which is by adding hot-wire component. The attempt was done in higher growth temperature, 400oC. Morphological characterizations, by using Scanning Electron Micrograph (SEM and Scanning Probe Microscopy (SPM, as well as the composition characterization, by using Energy Dispersion Analysis by X-Ray (EDAX, show convincing results that there are some signatures of CNT present.

  8. Direct synthesis of solid and hollow carbon nanospheres over NaCl crystals using acetylene by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chandra Kishore, S.; Anandhakumar, S.; Sasidharan, M., E-mail: sasidharan.m@res.srmuniv.ac.in

    2017-04-01

    Highlights: • Hollow and solid carbon nanospheres were synthesized by CVD method. • NaCl was used as template for direct growth of carbon nanospheres. • Separation of NaCl from the mixture is made easy by dissolving in water. • The hollow carbon nanospheres exhibit high specific capacity in Li-ion batteries than the graphite anodes. - Abstract: Carbon nanospheres (CNS) with hollow and solid morphologies have been synthesised by a simple chemical vapour deposition method using acetylene as a carbon precursor. Sodium chloride (NaCl) powder as a template was used for the direct growth of CNS via facile and low-cost approach. The effect of various temperatures (500 °C, 600 °C and 700 °C) and acetylene flow rates were investigated to study the structural evolution on the carbon products. The purified CNS thus obtained was characterized by various physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and cyclicvoltametry. The synthesised hollow nanospheres were investigated as anode materials for Li-ion batteries. After 25 cycles of repeated charge/discharge cycles, the discharge and charge capacities were found to be 574 mAh/g and 570 mAh/g, respectively which are significantly higher than the commercial graphite samples.

  9. The study of nitrogen inclusion in carbon nanotubes obtained by catalytic laser-induced chemical vapour deposition (C-LCVD)

    Science.gov (United States)

    Morjan, I. P.; Morjan, I.; Ilie, A.; Scarisoreanu, M.; Gavrila, L.; Dumitrache, F.; Vasile, E.; Turcu, R.; Miron, C.

    2017-12-01

    Nitrogen doped carbon nanotubes were grown on Fe2O3 nanoparticles deposited on silicon substrates, by laser-induced chemical vapour deposition of acetylene/ammonia mixtures. The concentration of the nitrogen has been controlled in the range 1-6 atomic% by adjusting the flow rate of ammonia, pressure and laser power. XPS and Raman spectroscopy were used to quantitatively assess the compositional and structural properties of the nitrogen-doped carbon nanotubes (Nsbnd CNTs). First order Raman spectra were deconvoluted assuming five vibrational modes and the integrated peak intensity ratio ID/IG and I2D/IG of all samples are displayed. We demonstrate that the relative amount of sp2 Cdbnd C carbon has the same trend as ID4/IG and the pyrrolic relative amount exhibits the same trend as I2D4/IG. The high resolution TEM images are consistent with the Raman and XPS results, revealing that the surface of the Nsbnd CNTs outer walls becomes more distorted at the highest content of N while the inner walls of the nanotube preserve a high crystallinity, corresponding to the lowest ID/IG ratio.

  10. Osteoconductive Potential of Barrier NanoSiO2 PLGA Membranes Functionalized by Plasma Enhanced Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Antonia Terriza

    2014-01-01

    Full Text Available The possibility of tailoring membrane surfaces with osteoconductive potential, in particular in biodegradable devices, to create modified biomaterials that stimulate osteoblast response should make them more suitable for clinical use, hopefully enhancing bone regeneration. Bioactive inorganic materials, such as silica, have been suggested to improve the bioactivity of synthetic biopolymers. An in vitro study on HOB human osteoblasts was performed to assess biocompatibility and bioactivity of SiO2 functionalized poly(lactide-co-glycolide (PLGA membranes, prior to clinical use. A 15 nm SiO2 layer was deposited by plasma enhanced chemical vapour deposition (PECVD, onto a resorbable PLGA membrane. Samples were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, and infrared spectroscopy (FT-IR. HOB cells were seeded on sterilized test surfaces where cell morphology, spreading, actin cytoskeletal organization, and focal adhesion expression were assessed. As proved by the FT-IR analysis of samples, the deposition by PECVD of the SiO2 onto the PLGA membrane did not alter the composition and other characteristics of the organic membrane. A temporal and spatial reorganization of cytoskeleton and focal adhesions and morphological changes in response to SiO2 nanolayer were identified in our model. The novedous SiO2 deposition method is compatible with the standard sterilization protocols and reveals as a valuable tool to increase bioactivity of resorbable PLGA membranes.

  11. Synthesis of carbon nanostructures from high density polyethylene (HDPE) and polyethylene terephthalate (PET) waste by chemical vapour deposition

    Science.gov (United States)

    Hatta, M. N. M.; Hashim, M. S.; Hussin, R.; Aida, S.; Kamdi, Z.; Ainuddin, AR; Yunos, MZ

    2017-10-01

    In this study, carbon nanostructures were synthesized from High Density Polyethylene (HDPE) and Polyethylene terephthalate (PET) waste by single-stage chemical vapour deposition (CVD) method. In CVD, iron was used as catalyst and pyrolitic of carbon source was conducted at temperature 700, 800 and 900°C for 30 minutes. Argon gas was used as carrier gas with flow at 90 sccm. The synthesized carbon nanostructures were characterized by FESEM, EDS and calculation of carbon yield (%). FESEM micrograph shows that the carbon nanostructures were only grown as nanofilament when synthesized from PET waste. The synthesization of carbon nanostructure at 700°C was produced smooth and the smallest diameter nanofilament compared to others. The carbon yield of synthesized carbon nanostructures from PET was lower from HDPE. Furthermore, the carbon yield is recorded to increase with increasing of reaction temperature for all samples. Elemental study by EDS analysis were carried out and the formation of carbon nanostructures was confirmed after CVD process. Utilization of polymer waste to produce carbon nanostructures is beneficial to ensure that the carbon nanotechnology will be sustained in future.

  12. Oil mist and vapour concentrations from drilling fluids: inter- and intra-laboratory comparison of chemical analyses.

    Science.gov (United States)

    Galea, Karen S; Searl, Alison; Sánchez-Jiménez, Araceli; Woldbæk, Torill; Halgard, Kristin; Thorud, Syvert; Steinsvåg, Kjersti; Krüger, Kirsti; Maccalman, Laura; Cherrie, John W; van Tongeren, Martie

    2012-01-01

    There are no recognized analytical methods for measuring oil mist and vapours arising from drilling fluids used in offshore petroleum drilling industry. To inform the future development of improved methods of analysis for oil mist and vapours this study assessed the inter- and intra-laboratory variability in oil mist and vapour analysis. In addition, sample losses during transportation and storage were assessed. Replicate samples for oil mist and vapour were collected using the 37-mm Millipore closed cassette and charcoal tube assembly. Sampling was conducted in a simulated shale shaker room, similar to that found offshore for processing drilling fluids. Samples were analysed at two different laboratories, one in Norway and one in the UK. Oil mist samples were analysed using Fourier transform infrared spectroscopy (FTIR), while oil vapour samples were analysed by gas chromatography (GC). The comparison of replicate samples showed substantial within- and between-laboratory variability in reported oil mist concentrations. The variability in oil vapour results was considerably reduced compared to oil mist, provided that a common method of calibration and quantification was adopted. The study also showed that losses can occur during transportation and storage of samples. There is a need to develop a harmonized method for the quantification of oil mist on filter and oil vapour on charcoal supported by a suitable proficiency testing scheme for laboratories involved in the analysis of occupational hygiene samples for the petroleum industry. The uncertainties in oil mist and vapour measurement have substantial implications in relation to compliance with occupational exposure limits and also in the reliability of any exposure-response information reported in epidemiological studies.

  13. Biocidal Silver and Silver/Titania Composite Films Grown by Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    D. W. Sheel

    2008-01-01

    Full Text Available This paper describes the growth and testing of highly active biocidal films based on photocatalytically active films of TiO2, grown by thermal CVD, functionally and structurally modified by deposition of nanostructured silver via a novel flame assisted combination CVD process. The resulting composite films are shown to be highly durable, highly photocatalytically active and are also shown to possess strong antibacterial behaviour. The deposition control, arising from the described approach, offers the potential to control the film nanostructure, which is proposed to be crucial in determining the photo and bioactivity of the combined film structure, and the transparency of the composite films. Furthermore, we show that the resultant films are active to a range of organisms, including Gram-negative and Gram-positive bacteria, and viruses. The very high-biocidal activity is above that expected from the concentrations of silver present, and this is discussed in terms of nanostructure of the titania/silver surface. These properties are especially significant when combined with the well-known durability of CVD deposited thin films, offering new opportunities for enhanced application in areas where biocidal surface functionality is sought.

  14. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2018-03-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  15. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2017-12-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  16. Effect of growth interruptions on TiO{sub 2} films deposited by plasma enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, D., E-mail: dyli@yzu.edu.cn [College of Mechanical Engineering, Yangzhou University, Yangzhou, 225127 (China); Goullet, A. [Institut des Matériaux Jean Rouxel (IMN), UMR CNRS 6502, 2 rue de la Houssinière, 44322, Nantes (France); Carette, M. [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré, 59652, Villeneuve d' Ascq (France); Granier, A. [Institut des Matériaux Jean Rouxel (IMN), UMR CNRS 6502, 2 rue de la Houssinière, 44322, Nantes (France); Landesman, J.P. [Institut de Physique de Rennes, UMR CNRS 6251, 263 av. Général Leclerc, 35042, Rennes (France)

    2016-10-01

    TiO{sub 2} films of ∼300 nm were deposited at low temperature (<140 °C) and pressure (0.4 Pa) using plasma enhanced chemical vapour deposition at the floating potential (V{sub f}) or the substrate self-bias voltage (V{sub b}) of −50 V. The impact of growth interruptions on the morphology, microstructure and optical properties of the films was investigated. The interruptions were carried out by stopping the plasma generation and gas injection once the increase of the layer thickness during each deposition step was about ∼100 nm. In one case of V{sub f}, the films of ∼300 nm exhibit a columnar morphology consisting of a bottom dense layer, an intermediate gradient layer and a top roughness layer. But the growth interruptions result in an increase of the dense layer thickness and a decrease of surface roughness. The film inhomogeneity has been identified by the in-situ real-time evolution of the kinetic ellipsometry (KE) parameters and the modeling process of spectroscopic ellipsometry (SE). The discrepancy of the refractive index measured by SE between bottom and upper layers can be reduced by growth interruptions. In the other case of V{sub b} = −50 V, the films exhibit a more compact arrangement which is homogeneous along the growth direction as confirmed by KE and SE. Both of Fourier transform infrared spectra and X-ray diffraction illustrate a phase transformation from anatase to rutile with the bias of −50 V, and also evidenced on the evolution of the refractive index dispersion curves. And a greatly increase of the refractive indice in the transparent range can be identified. However, the growth interruptions seem to have no influence on the morphology and optical properties in this case. - Highlights: • TiO{sub 2} films deposited by plasma processes at low temperature and pressure. • Influence of growth interruptions on structural and optical properties. • In-situ real-time ellipsometry measurements on film properties. • Structural and

  17. Magnetic and optical properties of (GaMn)N nanocrystalline powders prepared by the aerosol-assisted vapour phase synthesis and anaerobic imide route methods

    Energy Technology Data Exchange (ETDEWEB)

    Gosk, J B [Institute of Experimental Physics, Warsaw University, Hoza 69, 00-681 Warsaw (Poland); Drygas, M [Faculty of Fuels and Energy, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Janik, J F [Faculty of Fuels and Energy, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Palczewska, M [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Paine, R T [Department of Chemistry, University of New Mexico, Albuquerque, NM 87131 (United States); Twardowski, A [Institute of Experimental Physics, Warsaw University, Hoza 69, 00-681 Warsaw (Poland)

    2006-09-07

    Herein, we report a study on magnetic and optical properties of hexagonal (GaMn)N nanocrystalline powders obtained by two methods: aerosol-assisted vapour phase synthesis and anaerobic imide route. Measurements of the magnetization as a function of temperature and magnetic field for the powders show a typical paramagnetic behaviour. In addition, antiferromagnetic contribution originating from a residual MnO by-product and a small ferromagnetic contribution are observed. Magnetization measured as the function of magnetic field shows a smaller saturation effect than expected for non-interacting Mn-ions. Electron paramagnetic resonance (EPR) measurements reveal a single, structureless resonance line with a g-factor equal to 2.008{+-}0.003 indicating a presence of Mn{sup 2+}-centres in the samples. Both magnetic and EPR measurements suggest weak AF interactions between Mn-ions incorporated in (GaMn)N.

  18. Investigation of chemical vapour deposition diamond detectors by X- ray micro-beam induced current and X-ray micro-beam induced luminescence techniques

    CERN Document Server

    Olivero, P; Vittone, E; Fizzotti, F; Paolini, C; Lo Giudice, A; Barrett, R; Tucoulou, R

    2004-01-01

    Tracking detectors have become an important ingredient in high-energy physics experiments. In order to survive the harsh detection environment of the Large Hadron Collider (LHC), trackers need to have special properties. They must be radiation hard, provide fast collection of charge, be as thin as possible and remove heat from readout electronics. The unique properties of diamond allow it to fulfill these requirements. In this work we present an investigation of the charge transport and luminescence properties of "detector grade" artificial chemical vapour deposition (CVD) diamond devices developed within the CERN RD42 collaboration, performed by means of X-ray micro-beam induced current collection (XBICC) and X-ray micro- beam induced luminescence (XBIL) techniques. XBICC technique allows quantitative estimates of the transport parameters of the material to be evaluated and mapped with micrometric spatial resolution. In particular, the high resolution and sensitivity of the technique has allowed a quantitati...

  19. Characterization of thin TiO{sub 2} films prepared by plasma enhanced chemical vapour deposition for optical and photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk-Guzenda, A., E-mail: asobczyk@p.lodz.p [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Gazicki-Lipman, M.; Szymanowski, H.; Kowalski, J. [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Wojciechowski, P.; Halamus, T. [Department of Molecular Physics, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Tracz, A. [Centre for Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland)

    2009-07-31

    Thin titanium oxide films were deposited using a radio frequency (RF) plasma enhanced chemical vapour deposition method. Their optical properties and thickness were determined by means of ultraviolet-visible absorption spectrophotometry. Films of the optical parameters very close to those of titanium dioxide have been obtained at the high RF power input. Their optical quality is high enough to allow for their use in a construction of stack interference optical filters. At the same time, these materials exhibit strong photocatalytic effects. The results of structural analysis, carried out by Raman Shift Spectroscopy, show that the coatings posses amorphous structure. However, Raman spectra of the same films subjected to thermal annealing at 450 {sup o}C disclose an appearance of a crystalline form, namely that of anatase. Surface morphology of the films has also been characterized by Atomic Force Microscopy revealing granular, broccoli-like topography of the films.

  20. Optical and passivating properties of hydrogenated amorphous silicon nitride deposited by plasma enhanced chemical vapour deposition for application on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wight, Daniel Nilsen

    2008-07-01

    Within this thesis, several important subjects related to the use of amorphous silicon nitride made by plasma enhanced chemical vapour deposition as an anti-reflective coating on silicon solar cells are presented. The first part of the thesis covers optical simulations to optimise single and double layer anti-reflective coatings with respect to optical performance when situated on a silicon solar cell. The second part investigates the relationship between important physical properties of silicon nitride films when deposited under different conditions. The optical simulations were either based on minimising the reflectance off a silicon nitride/silicon wafer stack or maximising the transmittance through the silicon nitride into the silicon wafer. The former method allowed consideration of the reflectance off the back surface of the wafer, which occurs typically at wavelengths above 1000 nm due to the transparency of silicon at these wavelengths. However, this method does not take into consideration the absorption occurring in the silicon nitride, which is negligible at low refractive indexes but quite significant when the refractive index increases above 2.1. For high-index silicon nitride films, the latter method is more accurate as it considers both reflectance and absorbance in the film to calculate the transmittance into the Si wafer. Both methods reach similar values for film thickness and refractive index for optimised single layer anti-reflective coatings, due to the negligible absorption occurring in these films. For double layer coatings, though, the reflectance based simulations overestimated the optimum refractive index for the bottom layer, which would have lead to excessive absorption if applied to real anti-reflective coatings. The experimental study on physical properties for silicon nitride films deposited under varying conditions concentrated on the estimation of properties important for its applications, such as optical properties, passivation

  1. Sensitive chemical compass assisted by quantum criticality

    Science.gov (United States)

    Cai, C. Y.; Ai, Qing; Quan, H. T.; Sun, C. P.

    2012-02-01

    A radical-pair-based chemical reaction might be used by birds for navigation via the geomagnetic direction. The inherent physical mechanism is that the quantum coherent transition from a singlet state to triplet states of the radical pair could respond to a weak magnetic field and be sensitive to the direction of such a field; this then results in different photopigments to be sensed by the avian eyes. Here, we propose a quantum bionic setup, inspired by the avian compass, as an ultrasensitive probe of a weak magnetic field based on the quantum phase transition of the environments of the two electrons in the radical pair. We prove that the yield of the chemical products via recombination from the singlet state is determined by the Loschmidt echo of the environments with interacting nuclear spins. Thus quantum criticality of environments could enhance the sensitivity of detection of weak magnetic fields.

  2. Effects of Surface Modification of Nanodiamond Particles for Nucleation Enhancement during Its Film Growth by Microwave Plasma Jet Chemical Vapour Deposition Technique

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2014-01-01

    Full Text Available The seedings of the substrate with a suspension of nanodiamond particles (NDPs were widely used as nucleation seeds to enhance the growth of nanostructured diamond films. The formation of agglomerates in the suspension of NDPs, however, may have adverse impact on the initial growth period. Therefore, this paper was aimed at the surface modification of the NDPs to enhance the diamond nucleation for the growth of nanocrystalline diamond films which could be used in photovoltaic applications. Hydrogen plasma, thermal, and surfactant treatment techniques were employed to improve the dispersion characteristics of detonation nanodiamond particles in aqueous media. The seeding of silicon substrate was then carried out with an optimized spin-coating method. The results of both Fourier transform infrared spectroscopy and dynamic light scattering measurements demonstrated that plasma treated diamond nanoparticles possessed polar surface functional groups and attained high dispersion in methanol. The nanocrystalline diamond films deposited by microwave plasma jet chemical vapour deposition exhibited extremely fine grain and high smooth surfaces (~6.4 nm rms on the whole film. These results indeed open up a prospect of nanocrystalline diamond films in solar cell applications.

  3. Pengaruh Temperatur, Massa Zink, Substrat Dan Waktu Tahan Terhadap Struktur Dan Morfologi Zno Hasil Sintesis Dengan Metode Chemical Vapour Transport (CVT

    Directory of Open Access Journals (Sweden)

    Arisela Distyawan

    2013-09-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Material Zink Oksida (ZnO telah berhasil disintesis menggunakan metode Chemical Vapour Transport dengan bahan dasar prekursor berupa serbuk Zn yang dipanaskan hingga mencapai temperatur uap dalam furnace horisontal. Adapun variasi yang diberikan dalam penelitian adalah berupa temperatur pemanasan (850, 900, dan 950oC, massa prekursor Zn (0,15, 0,25, dan 0,35g, lama waktu sputtering substrat (90 dan 180 detik, dan waktu tahan khusus untuk mengetahui initial growth ZnO (10, 20, 30, 40, 50, dan 60 menit. Pembentukan Zink Oksida (ZnO dikonfirmasi melalui data X-RD, dimana telah terbentuk material ZnO dengan struktur hexagonal wurtzite. Berdarsarkan data XRD juga diketahui ukuran kristal pada sampel sputtering 90 detik mengalami penurunan bersamaan penambahan massa Zn. Dari hasil pengamatan SEM didapatkan bahwa morfologi permukaan lapisan tipis ZnO terdiri dari berbagai macam bentuk berupa nanoparticle, nanowires, nanorods, dan nanotetrapod. Lapisan Zno paling tebal sebesar ±350 nm pada sampel 950oC-0,15g sputter 90 detik. Semakin tinggi temperatur operasi berdampak peningkatan ukuran partikel. Pengujian FTIR turut menguatkan terbentuknya lapisan tipis di permukaan substrat Alumina. Hal ini didasarkan terjadinya penyerapan vibrasi yang membentuk lekukan pada kisaran area 509 cm-1 dari masing-masing sampel.

  4. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Science.gov (United States)

    Hu, Wen-Juan; Xie, Fen-Yan; Chen, Qiang; Weng, Jing

    2008-10-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  5. Corrosion resistance of amorphous hydrogenated SiC and diamond-like coatings deposited by r. f. -plasma-enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sella, C. (Lab. de Physique des Materiaux, CNRS, 92 Meudon (France)); Lecoeur, J. (Lab. d' Electrochimie Interfaciale, CNRS, 92 Meudon (France)); Sampeur, Y. (ICMC, 91 Le Coudray Montceaux (France)); Catania, P. (ICMC, 91 Le Coudray Montceaux (France))

    1993-10-08

    This paper reports on the properties and corrosion resistance of amorphous hydrogenated carbon and amorphous hydrogenated SiC films deposited by r.f.-plasma-enhanced chemical vapour deposition at low temperatures (below 200 C). SiC coatings were prepared from SiH[sub 4]-CH[sub 4] gas mixtures. Hydrogenated diamond-like coatings were deposited from classical CH[sub 4]-H[sub 2] mixtures. The influence of various deposition parameters was investigated. Microstructural and mechanical properties of the films were studied (density, hydrogen content, nanohardness, internal stress, critical load and friction coefficient). Two examples of corrosion resistance are given: (1) the corrosion resistance and biocompatibility of SiC and diamond-like coatings deposited on metal implants (Ti alloy) (the corrosion resistance is evaluated through potentiodynamic polarization tests in biological media; the biocompatibility of coated and uncoated metals is compared using differentiated human cell cultures); and (2) the corrosion resistance of SiC-coated magnesium in chloride-containing boric borate buffer at pH = 9.3 evaluated from anodic polarization curves and scanning electron microscopy studies. (orig.)

  6. Origin of the 2.45 eV luminescence band observed in ZnO epitaxial layers grown on c-plane sapphire by chemical vapour deposition

    Science.gov (United States)

    Saroj, R. K.; Dhar, S.

    2014-12-01

    Zinc oxide epitaxial layers have been grown on c-plane sapphire substrates by the chemical vapour deposition (CVD) technique. A structural study shows (0001)-oriented films with good crystalline quality. The temperature and excitation power dependence of the photoluminescence (PL) characteristics of these layers is studied as a function of various growth parameters, such as the growth temperature, oxygen flow rate and Zn flux, which suggest that the origin of the broad visible luminescence (VL), which peaks at 2.45 eV, is the transition between the conduction band and the Zn vacancy acceptor states. A bound excitonic transition observed at 3.32 eV in low temperature PL has been identified as an exciton bound to the neutral Zn vacancy. Our study also reveals the involvement of two activation processes in the dynamics of VL, which has been explained in terms of the fluctuation of the capture barrier height for the holes trapped in Zn vacancy acceptors. The fluctuation, which might be a result of the inhomogeneous distribution of Zn vacancies, is found to be associated with an average height of 7 and 90 meV, respectively, for the local and global maxima.

  7. Growth of cubic InN on GaP(1 0 0) with GaN buffer by metalorganic chemical vapour deposition

    Science.gov (United States)

    Kwon, S.-Y.; Sun, Q.; Kwak, J.; Seo, H.-C.; Han, J.

    2011-07-01

    Growth of cubic InN (c-InN) under N-rich condition was achieved by metalorganic chemical vapour deposition on GaP(1 0 0) substrates with a cubic GaN (c-GaN) buffer layer. Insertion of the c-GaN buffer layer suppressed In droplet formation in c-InN. X-ray diffraction and transmission electron microscopy investigations showed that the InN layers have zincblende structure with only a small fraction of oxide phase inclusions and no significant hexagonal InN is present. By systemically varying growth conditions, it was found that the c-InN growth is dominated mainly by In adatoms' surface diffusion and InN surface decomposition and three distinct regimes of c-InN growth are observed. The growth of c-InN on c-GaN/GaP(1 0 0) templates eventually followed a three-dimensional growth mode in the thermally activated growth regime and density and size distribution of c-InN dots significantly changed with substrate temperature and growth rate. These results provide a stronger understanding of the growth mechanism to design and engineer InN-based nanostructures with desired shapes for potential technological applications.

  8. Growth and characterization of germanium epitaxial film on silicon (001 with germane precursor in metal organic chemical vapour deposition (MOCVD chamber

    Directory of Open Access Journals (Sweden)

    Kwang Hong Lee

    2013-09-01

    Full Text Available The quality of germanium (Ge epitaxial film grown directly on a silicon (Si (001 substrate with 6° off-cut using conventional germane precursor in a metal organic chemical vapour deposition (MOCVD system is studied. The growth sequence consists of several steps at low temperature (LT at 400 °C, intermediate temperature ramp (LT-HT of ∼10 °C/min and high temperature (HT at 600 °C. This is followed by post-growth annealing in hydrogen at temperature ranging from 650 to 825 °C. The Ge epitaxial film of thickness ∼ 1 μm experiences thermally induced tensile strain of 0.11 % with a treading dislocation density (TDD of ∼107/cm2 and the root-mean-square (RMS roughness of ∼ 0.75 nm. The benefit of growing Ge epitaxial film using MOCVD is that the subsequent III-V materials can be grown in-situ without the need of breaking the vacuum hence it is manufacturing worthy.

  9. Radical-assisted chemical doping for chemically derived graphene

    Science.gov (United States)

    Ishikawa, Ryousuke; Ko, Pil Ju; Bando, Masashi; Kurokawa, Yasuyoshi; Sandhu, Adarsh; Konagai, Makoto

    2013-12-01

    Carrier doping of graphene is one of the most challenging issues that needs to be solved to enable its use in various applications. We developed a carrier doping method using radical-assisted conjugated organic molecules in the liquid phase and demonstrated all-wet fabrication process of doped graphene films without any vacuum process. Charge transfer interaction between graphene and dopant molecules was directly investigated by spectroscopic studies. The resistivity of the doped graphene films was drastically decreased by two orders of magnitude. The resistivity was improved by not only carrier doping but the improvement in adhesion of doped graphene flakes. First-principles calculation supported the model of our doping mechanism.

  10. The Liquid Vapour Interface

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

  11. Raman Spectroscopic Study of Carbon Nanotubes Prepared Using Fe/ZnO-Palm Olein-Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Syazwan Afif Mohd Zobir

    2012-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD method at 800–1000°C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein (PO, ferrocene in the presence of 0.05 M zinc nitrate, and a p-type silicon wafer were used as carbon source, catalyst precursor, and sample target, respectively. D, G, and G′ bands were observed at 1336–1364, 1559–1680, and 2667–2682 cm-1, respectively. Carbon nanotubes (CNTs with the highest degree of crystallinity were obtained at around 8000°C, and the smallest diameter of about 2 nm was deposited on the silicon substrate at 1000°C.

  12. Effect of reaction parameters on the growth of MWCNTs using mesoporous Sb/MCM-41 by chemical vapour deposition

    Science.gov (United States)

    Atchudan, R.; Pandurangan, A.; Subramanian, K.

    2011-11-01

    Mesoporous Si-MCM-41 molecular sieve was synthesized hydrothermally and different wt.% of Sb (1.0, 2.0, 3.0, 5.0, 10.0, 15.0 and 20.0) was loaded on it by wet impregnation method. The Sb/MCM-41 materials were characterized by various physico-chemical techniques such as XRD, TGA and TEM. The TEM image showed a honeycomb structure of the host material. They were used as catalytic templates for the growth of MWCNTs by CVD method with different temperatures at 700, 800, 900 and 1000 °C using acetylene as a carbon precursor. The reaction temperature was optimized for the better formation of MWCNTs and they were purified and then characterized by XRD, SEM, HR-TEM and Raman spectroscopy techniques. The formation of MWCNTs with diameter in the range of 4-6 nm was observed from HR-TEM. The good thermal stability and high productivity of catalyst observed in this study revealed that the 2 wt.% Sb loaded MCM-41 could be a promising support for the catalytic synthesis of MWCNTs at 800 °C by CVD method.

  13. Comparative investigation of Si-C-N Films prepared by plasma enhanced chemical vapour deposition and magnetron sputtering

    Science.gov (United States)

    Kozak, A. O.; Porada, O. K.; Ivashchenko, V. I.; Ivashchenko, L. A.; Scrynskyy, P. L.; Tomila, T. V.; Manzhara, V. S.

    2017-12-01

    This paper reports on the results of comparative investigations of Si-C-N films prepared by using both plasma enhanced chemical vapor deposition (PECVD) and DC magnetron sputtering (MS) at different nitrogen flow rates (FN2). The films were characterized by an atomic force microscope, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, nanoindentation and photoluminescence spectroscopy. All the deposited films were X-ray amorphous. For the PECVD films, nanohardness (H) and elastic module (E) increase with FN2, which can be assigned to decreasing the hydrogen content. On the contrary, for the films, deposited by magnetron sputtering, the values of H and E decrease, when FN2 increases. The latter is supposed to be due to decreasing a number of strong Si-C bonds and to increasing a number of weak Sisbnd N and Csbnd N bonds. The surface roughness of two types of the films is smaller compared to that of silicon substrates. An increase in nitrogen flow rate causes the smoothing of the film surfaces. The PECVD films deposited at high FN2 exhibit bright photoemission with the main peak at ∼440 nm. The intensity of this peak increases with increasing nitrogen content.

  14. Hydrogen production by ethanol partial oxidation over nano-iron oxide catalysts produced by chemical vapour synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Wael Ahmed Abou Taleb Sayed

    2011-01-13

    This work presents the experimental results of the synthesis of unsupported and supported SiC iron oxide nanoparticles and their catalytic activity towards ethanol partial oxidation. For comparison, further unsupported iron oxide phases were investigated towards the ethanol partial oxidation. These {gamma}-Fe{sub 2}O{sub 3} and {alpha}/{gamma}-Fe{sub 2}O{sub 3} phase catalysts were prepared by the CVS method using Fe(CO){sub 5} as precursor, supplied by another author. The {alpha}-Fe{sub 2}O{sub 3} and SiC nanoparticles were prepared by the CVS method using a home made hot wall reactor technique at atmospheric pressure. Ferrocene and tetramethylsilane were used as precursor for the production process. Process parameters of precursor evaporation temperature, precursor concentration, gas mixture velocity and gas mixture dilution were investigated and optimised to produce particle sizes in a range of 10 nm. For Fe{sub 2}O{sub 3}/SiC catalyst series production, a new hot wall reactor setup was used. The particles were produced by simultaneous thermal decomposition of ferrocene and tetramethylsilane in one reactor from both sides. The production parameters of inlet tube distance inside the reactor, precursor evaporation temperature and carrier gas flow were investigated to produce a series of samples with different iron oxide content. The prepared catalysts composition, physical and chemical properties were characterized by XRD, EDX, SEM, BET surface area, FTIR, XPS and dynamic light scattering (DLS) techniques. The catalytic activity for the ethanol gas-phase oxidation was investigated in a temperature range from 260 C to 290 C. The product distributions obtained over all catalysts were analysed with mass spectrometry analysis tool. The activity of bulk Fe{sub 2}O{sub 3} and SiC nanoparticles was compared with prepared nano-iron oxide phase catalysts. The reaction parameters, such as reaction temperature and O{sub 2}/ethanol ratio were investigated. The catalysts

  15. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  16. TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition; Sistema RTP: uma tecnica poderosa para o monitoramento da formacao de nanotubos de carbono durante o processo por deposicao de vapor quimico

    Energy Technology Data Exchange (ETDEWEB)

    Tristao, Juliana Cristina; Moura, Flavia Cristina Camilo; Lago, Rochel Montero, E-mail: rochel@ufmg.b [Universidade Federal de Minas Gerais (DQ/UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Sapag, Karim [Universidade Nacional de San Luis (Argentina). Lab. de Ciencias de Superficies y Medios Porosos

    2010-07-01

    In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al{sub 2}O{sub 3} and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields. (author)

  17. Virucidal efficacy of hydrogen peroxide vapour disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Terpstra, P.; Koopmans, M.; Duizer, E.

    2012-01-01

    Background: Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. Aim: To measure the

  18. Chemically assisted in situ recovery of oil shale

    Energy Technology Data Exchange (ETDEWEB)

    Ramierz, W.F.

    1993-12-31

    The purpose of the research project was to investigate the feasibility of the chemically assisted in situ retort method for recovering shale oil from Colorado oil shale. The chemically assisted in situ procedure uses hydrogen chloride (HCl), steam (H{sub 2}O), and carbon dioxide (CO{sub 2}) at moderate pressure to recovery shale oil from Colorado oil shale at temperatures substantially lower than those required for the thermal decomposition of kerogen. The process had been previously examined under static, reaction-equilibrium conditions, and had been shown to achieve significant shale oil recoveries from powdered oil shale. The purpose of this research project was to determine if these results were applicable to a dynamic experiment, and achieve penetration into and recovery of shale oil from solid oil shale. Much was learned about how to perform these experiments. Corrosion, chemical stability, and temperature stability problems were discovered and overcome. Engineering and design problems were discovered and overcome. High recovery (90% of estimated Fischer Assay) was observed in one experiment. Significant recovery (30% of estimated Fischer Assay) was also observed in another experiment. Minor amounts of freed organics were observed in two more experiments. Penetration and breakthrough of solid cores was observed in six experiments.

  19. Silicon nanowire photodetectors made by metal-assisted chemical etching

    Science.gov (United States)

    Xu, Ying; Ni, Chuan; Sarangan, Andrew

    2016-09-01

    Silicon nanowires have unique optical effects, and have potential applications in photodetectors. They can exhibit simple optical effects such as anti-reflection, but can also produce quantum confined effects. In this work, we have fabricated silicon photodetectors, and then post-processed them by etching nanowires on the incident surface. These nanowires were produced by a wet-chemical etching process known as the metal-assisted-chemical etching, abbreviated as MACE. N-type silicon substrates were doped by thermal diffusion from a solid ceramic source, followed by etching, patterning and contact metallization. The detectors were first tested for functionality and optical performance. The nanowires were then made by depositing an ultra-thin film of gold below its percolation thickness to produce an interconnected porous film. This was then used as a template to etch high aspect ratio nanowires into the face of the detectors with a HF:H2O2 mixture.

  20. 3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Z. C.; Christ, J. F.; Evans, K. A.; Arey, B. W.; Sweet, L. E.; Warner, M. G.; Erikson, R. L.; Barrett, C. A.

    2017-01-01

    We report the production of flexible, highly-conductive poly(vinylidene flouride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D-printing. This account further describes, for the first-time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (1 x 10-2 S / cm). The printed composites contain little residual metal particulate relative to parts from commercial PLA-nanocomposite material visualized by micro X-ray computed tomography (μ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15 % mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating, and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161 % after 3 minutes) generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.

  1. 3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform.

    Science.gov (United States)

    Kennedy, Z C; Christ, J F; Evans, K A; Arey, B W; Sweet, L E; Warner, M G; Erikson, R L; Barrett, C A

    2017-05-04

    We report the production of flexible, highly-conductive poly(vinylidene fluoride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D printing. This account further describes, for the first time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (∼3 × 10(-2) S cm(-1)). The printed composites contain little residual metal particulate relative to parts from commercial PLA-nanocomposite material visualized by micro-X-ray computed tomography (μ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15% mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161% after 3 minutes) being generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.

  2. Water vapour variability and trends in the Arctic stratosphere

    Science.gov (United States)

    Thölix, Laura; Kivi, Rigel; Backman, Leif; Karpechko, Alexey

    2014-05-01

    Water vapour in the upper troposphere-lower stratosphere (UTLS) is a radiatively and chemically important trace gas. Stratospheric water vapour also affects ozone chemistry through odd-hydrogen chemistry and formation of polar stratospheric clouds (PSC). Both transport and chemistry contribute to the extratropical lower stratospheric water vapour distribution and trends. The main sources of stratospheric water vapour are intrusion through the tropical tropopause and production from oxidation of methane. Accurate observations of UTLS water vapour are difficult to obtain due to the strong gradient in the water vapour profile over the tropopause. However, modelling the stratospheric water vapour distribution is challenging and accurate measurements are needed for model validation. Trends in Arctic water vapour will be analysed and explained in terms of contribution from different processes (transport and chemistry), using observations and chemistry transport model (CTM) simulations. Accurate water vapour soundings from Sodankylä will be used to study water vapour within the Arctic polar vortex, including process studies on formation of PSCs and dehydration. Water vapour profiles measured during the LAPBIAT atmospheric sounding campaign in Sodankylä in January 2010 indicated formation of ice clouds and dehydration. Effects on ozone chemistry will also be studied. Global middle atmospheric simulations have been performed with the FinROSE-ctm using ERA-Interim winds and temperatures. The FinROSE-ctm is a global middle atmosphere model that produces the distribution of 30 long-lived species and tracers and 14 short-lived species. The chemistry describes around 110 gas phase reactions, 37 photodissociation processes and the main heterogeneous reactions related to aerosols and polar stratospheric clouds.

  3. Waste remediation using in situ magnetically assisted chemical separation

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, L.; Buchholz, B.A.; Vandegrift, G.F.

    1993-11-01

    The magnetically assisted chemical separation process (MACS) combines the selective and efficient separation afforded by chemical sorption with the magnetic recovery of ferromagnetic particles. This process is being developed for treating the underground storage tanks at Hanford. These waste streams contain cesium, strontium, and transuranics (TRU) that must be removed before this waste can be disposed of as grout. The separation process uses magnetic particles coated with either (1) a selective ion exchange material or an organic extractant containing solvent (for cesium and strontium removal) or (2) solvents for selective separation of TRU elements (e.g., TRUEX process). These coatings, by their chemical nature, selectively separate the contaminants onto the particles, which can then be recovered from the tank using a magnet. Once the particles are removed, the contaminants can either be left on the loaded particles and added to the glass feed slurry or stripped into a small volume of solution so that the extracting particles can be reused. The status of chemistry and separation process is discussed in this paper.

  4. Excitation mechanism and thermal emission quenching of Tb ions in silicon rich silicon oxide thin films grown by plasma-enhanced chemical vapour deposition—Do we need silicon nanoclusters?

    Energy Technology Data Exchange (ETDEWEB)

    Podhorodecki, A., E-mail: artur.p.podhorodecki@pwr.wroc.pl; Golacki, L. W.; Zatryb, G.; Misiewicz, J. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Wang, J.; Jadwisienczak, W. [School of EECS, Ohio University, Stocker Center 363, Athens, Ohio 45701 (United States); Fedus, K. [Institute of Physics, Nicholas Copernicus University, Grudziadzka 5/7, 87-100 Torun (Poland); Wojcik, J.; Wilson, P. R. J.; Mascher, P. [Department of Engineering Physics and Centre for Emerging Device Technologies, McMaster University, 1280 Main St. W, Hamilton, Ontario L8S4L7 (Canada)

    2014-04-14

    In this work, we will discuss the excitation and emission properties of Tb ions in a Silicon Rich Silicon Oxide (SRSO) matrix obtained at different technological conditions. By means of electron cyclotron resonance plasma-enhanced chemical vapour deposition, undoped and doped SRSO films have been obtained with different Si content (33, 35, 39, 50 at. %) and were annealed at different temperatures (600, 900, 1100 °C). The samples were characterized optically and structurally using photoluminescence (PL), PL excitation, time resolved PL, absorption, cathodoluminescence, temperature dependent PL, Rutherford backscattering spectrometry, Fourier transform infrared spectroscopy and positron annihilation lifetime spectroscopy. Based on the obtained results, we discuss how the matrix modifications influence excitation and emission properties of Tb ions.

  5. Dislocation-assisted tunnelling of charge carriers across the Schottky barrier on the hydride vapour phase epitaxy grown GaN

    Science.gov (United States)

    Chatterjee, Abhishek; Khamari, Shailesh K.; Dixit, V. K.; Oak, S. M.; Sharma, T. K.

    2015-11-01

    Barrier height and Ideality factor of Ni/n-GaN Schottky diodes are measured by performing temperature dependent current-voltage measurements. The measured value of barrier height is found to be much smaller than the theoretically calculated Schottky-Mott barrier height for the Ni/n-GaN diodes. Furthermore, a high value of ideality factor (>2) is measured at low temperatures. In order to understand these results, we need to consider a double Gaussian distribution of barrier height where the two components are related to the thermionic emission and thermionic filed emission mediated by dislocation-assisted tunnelling of carriers across the Schottky barrier. Thermionic emission is seen to dominate at temperatures higher than 170 K while the dislocation-assisted tunnelling dominates at low temperatures. The value of characteristic tunnelling energy measured from the forward bias current-voltage curves also confirms the dominance of dislocation-assisted tunnelling at low temperatures which is strongly corroborated by the Hall measurements. However, the value of characteristic tunnelling energy for high temperature range cannot be supported by the Hall results. This discrepancy can be eliminated by invoking a two layer model to analyse the Hall data which confirms that the charged dislocations, which reach the sample surface from the layer-substrate interface, provide an alternate path for the transport of carriers. The dislocation-assisted tunnelling of carriers governs the values of Schottky diode parameters at low temperature and the same is responsible for the observed inhomogeneity in the values of barrier height. The present analysis is applicable wherever the charge transport characteristics are severely affected by the presence of a degenerate layer at GaN-Sapphire interface and dislocations lines pierce the Schottky junction to facilitate the tunnelling of carriers.

  6. Radiolysis and hydrolysis of magnetically assisted chemical separation particles

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B.A.; Nunez, L.; Vandegrift, G.F.

    1995-05-01

    The magnetically assisted chemical separation (MACS) process is designed to separate transuranic (TRU) elements out of high-level waste (HLW) or TRU waste. Magnetic microparticles (1--25 {mu}m) were coated with octyl (phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP) and tested for removing TRU elements from acidic nitrate solutions. The particles were contacted with nitric acid solutions and Hanford plutonium finishing plant (PFP) simulant, irradiated with a high intensity {sup 60}Co {gamma}-ray source, and evaluated for effectiveness in removing TRU elements from 2m HNO{sub 3} solutions. The resistance of the coatings and magnetic cores to radiolytic damage and hydrolytic degradation was investigated by irradiating samples of particles suspended in a variety of solutions with doses of up to 5 Mrad. Transmission electron microscopy (TEM), magnetic susceptibility measurements, and physical observations of the particles and suspension solutions were used to assess physical changes to the particles. Processes that affect the surface of the particles dramatically alter the binding sites for TRU in solution. Hydrolysis played a larger role than radiolysis in the degradation of the extraction capacity of the particles.

  7. Kinetics of laser-assisted carbon nanotube growth

    NARCIS (Netherlands)

    Burgt, Y. van de; Bellouard, Y.; Mandamparambil, R.

    2014-01-01

    Laser-assisted chemical vapour deposition (CVD) growth is an attractive mask-less process for growing locally aligned carbon nanotubes (CNTs) in selected places on temperature sensitive substrates. The nature of the localized process results in fast carbon nanotube growth with high experimental

  8. High-quality Ge/Si{sub 0.4}Ge{sub 0.6} multiple quantum wells for photonic applications: growth by reduced pressure chemical vapour deposition and structural characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xuechao; Myronov, M; Dobbie, A; Morris, R J H; Leadley, D R, E-mail: d.r.leadley@warwick.ac.uk [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2011-02-09

    Strain-symmetrized Ge/SiGe multiple quantum wells have been grown on a thin (2.1 {mu}m) relaxed Si{sub 0.2}Ge{sub 0.8}/Ge/Si(1 0 0) virtual substrate (VS) by reduced pressure chemical vapour deposition. Such structures are of interest in optoelectronic applications for which the structural integrity of the quantum well layers, after processing, is critical. The layer composition, thickness and interface quality have been studied for wafers both as-grown and after annealing between 550 and 700 deg. C. Transmission electron microscopy indicated precise thickness control of {+-}0.1 nm and sharp abruptness between the Ge QWs and SiGe barrier layers. A smooth surface was observed, with an average rms roughness of 1.5 {+-} 0.1 nm determined by atomic force microscopy. High-resolution x-ray diffraction (HR-XRD) indicated that both the QWs and barriers were fully strained compared with the relaxed VS. The thermal stability of the epilayers was investigated both by ultra low energy secondary ion mass spectroscopy of post-growth annealed layers and by in situ annealing in a high temperature HR-XRD stage. No obvious interdiffusion and strain relaxation was observed provided the annealing temperature was below 600 deg. C, but significant atomic rearrangement was evident for greater thermal budgets, thereby setting an upper processing temperature for this type of structure.

  9. Size- and density-controlled deposition of Ag nanoparticle films by a novel low-temperature spray chemical vapour deposition method—research into mechanism, particle growth and optical simulation

    Science.gov (United States)

    Liu, Yang; Plate, Paul; Hinrichs, Volker; Köhler, Tristan; Song, Min; Manley, Phillip; Schmid, Martina; Bartsch, Peter; Fiechter, Sebastian; Lux-Steiner, Martha Ch.; Fischer, Christian-Herbert

    2017-04-01

    Ag nanoparticles have attracted interest for plasmonic absorption enhancement of solar cells. For this purpose, well-defined particle sizes and densities as well as very low deposition temperatures are required. Thus, we report here a new spray chemical vapour deposition method for producing Ag NP films with independent size and density control at substrate temperatures even below 100 °C, which is much lower than for many other techniques. This method can be used on different substrates to deposit Ag NP films. It is a reproducible, low-cost process which uses trimethylphosphine (hexafluoroacetylacetonato) silver as a precursor in alcoholic solution. By systematic variation of deposition parameters and classic experiments, mechanisms of particle growth and of deposition processes as well as the low decomposition temperature of the precursor could be explained. Using the 3D finite element method, absorption spectra of selected samples were simulated, which fitted well with the measured results. Hence, further applications of such Ag NP films for generating plasmonic near field can be predicted by the simulation.

  10. Size- and density-controlled deposition of Ag nanoparticle films by a novel low-temperature spray chemical vapour deposition method—research into mechanism, particle growth and optical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang, E-mail: yang.liu@helmholtz-berlin.de; Plate, Paul, E-mail: paul.plate@helmholtz-berlin.de; Hinrichs, Volker; Köhler, Tristan; Song, Min; Manley, Phillip; Schmid, Martina [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany); Bartsch, Peter [Beuth Hochschule für Technik Berlin, Fachbereich VIII Maschinenbau, Veranstaltungstechnik, Verfahrenstechnik (Germany); Fiechter, Sebastian; Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany); Fischer, Christian-Herbert [Freie Universität Berlin, Institute of Chemistry and Biochemistry (Germany)

    2017-04-15

    Ag nanoparticles have attracted interest for plasmonic absorption enhancement of solar cells. For this purpose, well-defined particle sizes and densities as well as very low deposition temperatures are required. Thus, we report here a new spray chemical vapour deposition method for producing Ag NP films with independent size and density control at substrate temperatures even below 100 °C, which is much lower than for many other techniques. This method can be used on different substrates to deposit Ag NP films. It is a reproducible, low-cost process which uses trimethylphosphine (hexafluoroacetylacetonato) silver as a precursor in alcoholic solution. By systematic variation of deposition parameters and classic experiments, mechanisms of particle growth and of deposition processes as well as the low decomposition temperature of the precursor could be explained. Using the 3D finite element method, absorption spectra of selected samples were simulated, which fitted well with the measured results. Hence, further applications of such Ag NP films for generating plasmonic near field can be predicted by the simulation.

  11. Spontaneuos and Parametric Processes in Warm Rubidium Vapours

    Directory of Open Access Journals (Sweden)

    Dąbrowski M.

    2014-12-01

    Full Text Available Warm rubidium vapours are known to be a versatile medium for a variety of experiments in atomic physics and quantum optics. Here we present experimental results on producing the frequency converted light for quantum applications based on spontaneous and stimulated processes in rubidium vapours. In particular, we study the efficiency of spontaneously initiated stimulated Raman scattering in the Λ-level configuration and conditions of generating the coherent blue light assisted by multi-photon transitions in the diamond-level configuration. Our results will be helpful in search for new types of interfaces between light and atomic quantum memories.

  12. Study on chemical mechanical polishing of silicon wafer with megasonic vibration assisted.

    Science.gov (United States)

    Zhai, Ke; He, Qing; Li, Liang; Ren, Yi

    2017-09-01

    Chemical mechanical polishing (CMP) is the primary method to realize the global planarization of silicon wafer. In order to improve this process, a novel method which combined megasonic vibration to assist chemical mechanical polishing (MA-CMP) is developed in this paper. A matching layer structure of polishing head was calculated and designed. Silicon wafers are polished by megasonic assisted chemical mechanical polishing and traditional chemical mechanical polishing respectively, both coarse polishing and precision polishing experiments were carried out. With the use of megasonic vibration, the surface roughness values Ra reduced from 22.260nm to 17.835nm in coarse polishing, and the material removal rate increased by approximately 15-25% for megasonic assisted chemical mechanical polishing relative to traditional chemical mechanical polishing. Average Surface roughness values Ra reduced from 0.509nm to 0.387nm in precision polishing. The results show that megasonic assisted chemical mechanical polishing is a feasible method to improve polishing efficiency and surface quality. The material removal and finishing mechanisms of megasonic vibration assisted polishing are investigated too. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Estimation of vapour pressure and partial pressure of subliming ...

    Indian Academy of Sciences (India)

    Administrator

    temperature curves are calculated at 80, 160 and 1000 mbar for salicylic acid and vanadyl bis-2,4- pentanedionate, a precursor used for chemical vapour deposition of vanadium oxides. Using a modification of the Langmuir equation, the partial pressure of these materials at different total pressures is also determined.

  14. Study of three dimensional germanium islands and ultrathin Si{sub x}Ge{sub 1-x} films grown by chemical vapour deposition on Si(111)-(7 x 7)

    Energy Technology Data Exchange (ETDEWEB)

    Gopalakrishnan, Selvi

    2005-07-15

    This work probed at the atomic level, processes that occur during the Ge three dimensional island formation and on ultrathin Si{sub x}Ge{sub 1-x} epitaxial growth by chemical vapour deposition on the Si(111)-(7 x 7) substrate with the aid of surface probe techniques such as STM and AFM, XPS, as well as TEM imaging of any 3D island formation. This work could essentially be divided into two parts. The first part studied the growth of the strained Ge on Si system with emphasis on the characterisation of the CVD grown three dimensional germanium islands on a standard Si(111)-(7 x 7) substrate as well as on a surface modified Si(111)-(7 x 7) substrate. The characterisation was carried out using a combination of techniques. XPS was used to calculate the effective coverages of deposited germanium, the STM was used to image the top most layers whenever possible and AFM, cross-sectional TEM and HRTEM to image the three dimensional islands. The possible causes of the surface modification were also examined. In the second part of this work the growth morphologies ultrathin Si{sub x}Ge{sub 1-x} layers grown on the Si(111)-(7 x 7) substrate at 750 K where the hydrogen desorption rate from the Si(111) surface is low and at 850 K which was the temperature at which the rate of hydrogen desorption from the Si(111) surface was a maximum were investigated. In addition modelling of ultrathin layer growth was carried out using two existing growth models. (orig.)

  15. Chemical Assistance in Refolding of Bacterial Inclusion Bodies

    Directory of Open Access Journals (Sweden)

    Mona Alibolandi

    2011-01-01

    Full Text Available Escherichia coli is one of the most widely used hosts for the production of recombinant proteins but insoluble expression of heterologous proteins is a major bottleneck in production of recombinant proteins in E. coli. In vitro refolding of inclusion body into proteins with native conformations is a solution for this problem but there is a need for optimization of condition for each protein specifically. Several approaches have been described for in vitro refolding; most of them involve the use of additives for assisting correct folding. Cosolutes play a major role in refolding process and can be classified according to their function as aggregation suppressors and folding enhancers. This paper presents a review of additives that are used in refolding process of insoluble recombinant proteins in small scale and industrial processes.

  16. Plasmon-assisted chemical reactions revealed by high-vacuum tip-enhanced Raman spectroscopy

    Science.gov (United States)

    Lu, Shuaicheng; Sheng, Shaoxiang; Zhang, Zhenglong; Xu, Hongxing; Zheng, Hairong

    2014-08-01

    Tip-enhanced Raman spectroscopy (TERS) is the technique that combines the nanoscale spatial resolution of a scanning probe microscope and the highly sensitive Raman spectroscopy enhanced by the surface plasmons. It is suitable for chemical analysis at nanometer scale. Recently, TERS exhibited powerful potential in analyzing the chemical reactions at nanoscale. The high sensitivity and spatial resolution of TERS enable us to learn the reaction processes more clearly. More importantly, the chemical reaction in TERS is assisted by surface plasmons, which provides us an optical method to manipulate the chemical reactions at nanoscale. Here using our home-built high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) setup, we successfully observed the plasmon-assisted molecule dimerization and dissociation reactions. In HV-TERS system, under laser illumination, 4-nitrobenzenethiol (4NBT) molecules can be dimerized to p,p'-dimercaptoazobenzene (DMAB), and dissociation reaction occurs for malachite green (MG) molecules. Using our HV-TERS setup, the dynamic processes of the reactions are clearly revealed. The chemical reactions can be manipulated by controlling the plasmon intensity through changing the power of the incident laser, the tunneling current and the bias voltage. We also investigated the role of plasmonic thermal effect in the reactions by measuring both the Stokes and anti- Stokes Raman peaks. Our findings extend the applications of TERS, which can help to study the chemical reactions and understand the dynamic processes at single molecular level, and even design molecules by the plasmon-assisted chemical reactions.

  17. Gallium assisted plasma enhanced chemical vapor deposition of silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zardo, I; Roessler, J; Frimmer, M; Fontcuberta i Morral, A [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Yu, L; Alet, Pierre Jean; Roca i Cabarrocas, P [LPICM, Ecole Polytechnique, CNRS, F-91128 Palaiseau (France); Conesa-Boj, S; Estrade, S; Peiro, F; Arbiol, J; Morante, J R [EME/XaRMAE/IN2UB, Departamento d' Electronica, Universitat de Barcelona, MartIi Franques, E-08028, Barcelona (Spain)

    2009-04-15

    Silicon nanowires have been grown with gallium as catalyst by plasma enhanced chemical vapor deposition. The morphology and crystalline structure has been studied by electron microscopy and Raman spectroscopy as a function of growth temperature and catalyst thickness. We observe that the crystalline quality of the wires increases with the temperature at which they have been synthesized. The crystalline growth direction has been found to vary between <111> and <112>, depending on both the growth temperature and catalyst thickness. Gallium has been found at the end of the nanowires, as expected from the vapor-liquid-solid growth mechanism. These results represent good progress towards finding alternative catalysts to gold for the synthesis of nanowires.

  18. Isothermal Reactor for Continuous Flow Microwave-Assisted Chemical Reaction

    Science.gov (United States)

    Matsuzawa, Mitsuhiro; Togashi, Shigenori; Hasebe, Shinji

    An isothermal reactor in which reaction solutions can be controlled at constant temperature under constant microwave irradiation was developed. This is useful for investigating microwave effects on chemical reactions that are not observed under conventional heating conditions. We devised a structure in which a heat-transfer medium with a low dielectric loss factor, which hardly absorbs any microwaves, flowed outside a spiral reaction tube and designed the basic structure of the reactor using electromagnetic simulation to optimize the energy absorption rate. The conditions for increasing the temperature controlling ability of the reactor were also investigated theoretically and experimentally by taking into consideration the influences of three elements: the velocity of the internal fluid, the material for the tube, and the velocity of the external fluid. The velocity of the external fluid had the greatest influence on temperature controlling ability and the material for the tube had the least influence under the experimental conditions. The overall heat transfer coefficient was about 3.9×102 W/(m2·K) when water flowed through the quartz reaction tube at 7.1 mm/s and the external fluid flowed outside the tube at 44 mm/s. We also tested and confirmed that the temperature of water used as internal fluid could be controlled to within ±1.5 K at 309.3 K when microwaves at 26 W were irradiated into the reactor, whereas the temperature of water was over 373 K and boiled without the heat-transfer medium flowing outside the reaction tube using a conventional method of microwave heating. In addition, we investigated microwave effects on Suzuki-Miyaura coupling reaction using the developed isothermal reactor and we confirmed that the temperatures were controlled well in the reactor. The yields obtained by microwave heating were almost the same as that obtained by oil-bath heating.

  19. Effect of anatomical characteristics and chemical components on microwave-assisted liquefaction of bamboo wastes

    Science.gov (United States)

    JiuLong Xie; XingYan Huang; JinQiu Qi; Chung Hse; Todd Shupe

    2014-01-01

    The epidermis layer waste (ELW) and the inner layer waste (ILW) were removed from Phyllostachys pubescens bamboo, and the anatomical characteristics and chemical components of these wastes were comparatively investigated. Both the ELW and the ILW were subjected to a microwave-assisted liquefaction process to evaluate the relationship between bamboo...

  20. Low Temperature Growth of In2O3and InN Nanocrystals on Si(111 via Chemical Vapour Deposition Based on the Sublimation of NH4Cl in In

    Directory of Open Access Journals (Sweden)

    Tsokkou Demetra

    2009-01-01

    Full Text Available Abstract Indium oxide (In2O3 nanocrystals (NCs have been obtained via atmospheric pressure, chemical vapour deposition (APCVD on Si(111 via the direct oxidation of In with Ar:10% O2at 1000 °C but also at temperatures as low as 500 °C by the sublimation of ammonium chloride (NH4Cl which is incorporated into the In under a gas flow of nitrogen (N2. Similarly InN NCs have also been obtained using sublimation of NH4Cl in a gas flow of NH3. During oxidation of In under a flow of O2the transfer of In into the gas stream is inhibited by the formation of In2O3around the In powder which breaks up only at high temperatures, i.e.T > 900 °C, thereby releasing In into the gas stream which can then react with O2leading to a high yield formation of isolated 500 nm In2O3octahedrons but also chains of these nanostructures. No such NCs were obtained by direct oxidation forT G < 900 °C. The incorporation of NH4Cl in the In leads to the sublimation of NH4Cl into NH3and HCl at around 338 °C which in turn produces an efficient dispersion and transfer of the whole In into the gas stream of N2where it reacts with HCl forming primarily InCl. The latter adsorbs onto the Si(111 where it reacts with H2O and O2leading to the formation of In2O3nanopyramids on Si(111. The rest of the InCl is carried downstream, where it solidifies at lower temperatures, and rapidly breaks down into metallic In upon exposure to H2O in the air. Upon carrying out the reaction of In with NH4Cl at 600 °C under NH3as opposed to N2, we obtain InN nanoparticles on Si(111 with an average diameter of 300 nm.

  1. Chalcogenoether complexes of Nb(v) thio- and seleno-halides as single source precursors for low pressure chemical vapour deposition of NbS2 and NbSe2 thin films.

    Science.gov (United States)

    Chang, Yao-Pang; Hector, Andrew L; Levason, William; Reid, Gillian

    2017-08-14

    NbSCl3 was obtained via reaction of NbCl5 with S(SiMe3)2 in anhydrous CH2Cl2, whilst in MeCN solution the same reaction gives [NbSCl3(MeCN)2]. [NbSeCl3(MeCN)2] was obtained similarly from NbCl5 with Se(SiMe3)2. The chalcogenoether complexes, [NbSCl3(ER2)] (E = S: R = Me, nBu; E = Se: R = nBu), were obtained from reaction of NbCl5, ER2 and S(SiMe3)2 in CH2Cl2. The structure of the [Nb2S2Cl6(SMe2)2] reveals a Cl-bridged dimer with the SMe2 ligands disposed syn. The Cl bridges are highly asymmetric, with the long Nb-Cl bond trans Nb[double bond, length as m-dash]S. The complexes, [NbSCl3(L-L)] (L-L = MeSCH2CH2SMe, MeS(CH2)3SMe, iPrSCH2CH2SiPr, MeSe(CH2)3SeMe and nBuS(CH2)3SnBu), were obtained from reaction of L-L with preformed [NbSCl3(MeCN)2]. The structures of the Me-substituted complexes reveal distorted octahedral monomers with the neutral ligands trans to S/Cl. Solution 1H and 77Se{1H} NMR data showed that the neutral ligands are partially dissociated and undergoing fast exchange at ambient temperatures in CH2Cl2 solution, consistent with weak Lewis acidity for NbSCl3. The complexes containing nBu-substituted ligands have been used as single source precursors for low pressure chemical vapour deposition (CVD) of 3R-NbS2 thin films. 2H-NbSe2 thin films were also obtained via low pressure CVD using [NbSe2Cl3(SenBu2)]. The thin films were characterised by grazing incidence and in-plane XRD, pole figure analysis, scanning electron microscopy and energy dispersive X-ray analysis.

  2. Sistema RTP: uma técnica poderosa para o monitoramento da formação de nanotubos de carbono durante o processo por deposição de vapor químico TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition

    Directory of Open Access Journals (Sweden)

    Juliana Cristina Tristão

    2010-01-01

    Full Text Available In this work, a TPR (Temperature Programmed Reduction system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition, The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al2O3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields.

  3. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); Garcia, L.V. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); Loredo, S.L. [Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, PIIT, Apodaca, Nuevo León (Mexico); Krishnan, B. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66455 (Mexico); CIIDIT—Universidad Autónoma de Nuevo León, Apodaca, Nuevo León (Mexico); and others

    2017-01-30

    Highlights: • Antimony sulfide thin films were prepared by normal CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • These films were photoconductive. - Abstract: Antimony sulfide (Sb{sub 2}S{sub 3}) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb{sub 2}S{sub 3} thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb{sub 2}S{sub 3} thin films for optoelectronic applications.

  4. Surface polish of PLA parts in FDM using dichloromethane vapour

    Directory of Open Access Journals (Sweden)

    Jin Yifan

    2017-01-01

    Full Text Available Fused deposition modelling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely limited by poor surface roughness. Thus it is necessary to adopt some operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modelling (FDM. The purpose of this paper is to decrease the surface roughness for polylactic acid (PLA parts in FDM. The chemical reaction mechanism during the treating process is analysed. Then NaOH solution and dichloromethane vapour are used to treat FDM specimens respectively. A 3D laser microscope has been applied to assess the effects in terms of surface topography and roughness. The experimental results show that treatment using dichloromethane vapour performs much better than NaOH solution. Compared with the untreated group, surface roughness obtained through vapour treatment decreases by 88 per cent. This research has been conducted to provide a better method to treat PLA parts using chemical reagents.

  5. Renewable platform chemicals from directional microwave-assisted liquefaction coupling stepwise extraction of waste biomass

    Science.gov (United States)

    Junfeng Feng; Chungyun Hse; Zhongzhi Yang; Kui Wang; Jianchun Jiang; Junming Xu

    2017-01-01

    Directional microwave-assisted liquefaction and stepwise extraction are introduced for producing platform chemicals: aromatics and monosaccharides. When sulfuric acid was used as a catalyst, a 45% monosaccharides yield and a 29% aromatics yield were obtained from bamboo with 0.3 g catalyst per 18 g methanol and 2 g bamboo at 160 °C with 10 min. Approximately 78–86 wt%...

  6. Coping without doping: Exploring associations between psychological stress and chemical assistance in high performance rugby.

    OpenAIRE

    Didymus, FF; Backhouse, SH

    2015-01-01

    OBJECTIVES: To explore associations between rugby players’ stressful experiences, their coping resources, and their use of chemical assistance.\\ud DESIGN: A qualitative research design was adopted. Lazarus’ (1999) cognitive-motivational-relational theory was used as the theoretical lens to address the study objectives.\\ud METHODS: Ten male (n=7) and female (n=3) high level rugby league and union players (Mage = 22.6, SD = 2.80) were interviewed using a semi-structured approach. A high level p...

  7. Intercomparison on measurement of water vapour permeability

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard

    Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001).......Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001)....

  8. Gas and vapour detection using polypyrrole

    NARCIS (Netherlands)

    Leur, R.H.M. van de; Waal, A. van der

    1999-01-01

    The vapours of organic solvents like toluene, butanon, and ethanol do effect the electrical conductivity of electrochemically synthesised polypyrrole. This property allows the use of polypyrrole in sensors for vapour detection. The conductivity is also a function of temperature and the history of

  9. Development of green vapour corrosion inhibitor

    Science.gov (United States)

    Asmara, Y. P.; Suraj, V.; Siregar, J. P.; Kurniawan, T.; Bachtiar, D.; Mohamed, N. M. Z. N.

    2017-10-01

    Corrosion control using inhibitor is an effective method to protect carbon steel from corrosion. Due to environmental toxicity of chemical inorganic corrosion inhibitors (synthetic), green inhibitors are potentially to develop. In atmospheric conditions, green vapour corrosion inhibitors are the best solutions to replace the uses of inorganic corrosion inhibitors. This research used chemical acid extraction from the key lime (citrus aurantiifolia) leaves and seeds. They are used as the main ingredients to produce this effective green corrosion inhibitor. The experiments investigated effects of corrosion inhibition on corrosion rate of low carbon steel in 3% NaCl solution using both fog salt chamber and electrochemical cell. Using salt fog chamber to represent atmospheric conditions, and corrosion rates are evaluated visually and calculated using weight loss methods. Corrosion rate on electrochemical cell were calculated using linear polarization resistance (LPR) methods. All of the experiments were set in natural conditions at pH 7. Using weight loss for three days exposure time, the efficiency of the inhibitor reached 82.39%.

  10. Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

    Energy Technology Data Exchange (ETDEWEB)

    Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.; Tripathi, S. K., E-mail: surya@pu.ac.in [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (INDIA) Fax: +91-172-2783336; Tel.:+91-172-2544362 (India)

    2016-05-06

    Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposure with vapours. A variation in the activation energies was also observed with exposure of vapours.

  11. CdS thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, L.V.; Mendivil, M.I.; Garcia Guillen, G.; Aguilar Martinez, J.A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2015-05-01

    Highlights: • CdS thin films by conventional CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • Improved dark conductivity and good photocurrent response for the LACBD CdS. - Abstract: In this work, we report the preparation and characterization of CdS thin films by laser assisted chemical bath deposition (LACBD). CdS thin films were prepared from a chemical bath containing cadmium chloride, triethanolamine, ammonium hydroxide and thiourea under various deposition conditions. The thin films were deposited by in situ irradiation of the bath using a continuous laser of wavelength 532 nm, varying the power density. The thin films obtained during deposition of 10, 20 and 30 min were analyzed. The changes in morphology, structure, composition, optical and electrical properties of the CdS thin films due to in situ irradiation of the bath were analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The thin films obtained by LACBD were nanocrystalline, photoconductive and presented interesting morphologies. The results showed that LACBD is an effective synthesis technique to obtain nanocrystalline CdS thin films having good optoelectronic properties.

  12. 21 CFR 173.315 - Chemicals used in washing or to assist in the peeling of fruits and vegetables.

    Science.gov (United States)

    2010-04-01

    ... peeling of fruits and vegetables. 173.315 Section 173.315 Food and Drugs FOOD AND DRUG ADMINISTRATION... used in washing or to assist in the peeling of fruits and vegetables. Chemicals may be safely used to wash or to assist in the peeling of fruits and vegetables in accordance with the following conditions...

  13. Low-Temperature Deposition of Zinc Oxide Film by Plasma-Assisted Mist Chemical Vapor Deposition

    Science.gov (United States)

    Takenaka, Kosuke; Okumura, Yusuke; Setsuhara, Yuichi

    2012-08-01

    Zinc oxide (ZnO) film deposition using a plasma-assisted mist chemical vapor deposition (CVD) with an inductively-coupled plasma source has been performed and the effects of the plasma exposure on film properties have been investigated with oxygen mixture ratio as a parameter. With increasing oxygen mixture ratio to Ar+O2(10%), the X-ray diffraction (XRD) results showed evident peaks of ZnO(0002), indicating that highly c-axis-oriented films were grown at low substrate temperatures below 200 °C. The deposition rate of ZnO films was as high as 100 nm/min. ZnO films with an optical transmittance of 75% for the visible region and a band gap energy of 3.32 eV have been obtained by using plasma-assisted mist CVD.

  14. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Landsberger, S. [Univ. of Illinois, Urbana, IL (United States)

    1995-05-01

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration.

  15. Study of the efficiency of chemically assisted enucleation method for handmade cloning in goat (Capra hircus).

    Science.gov (United States)

    Akshey, Y S; Malakar, D; De, A K; Jena, M K; Sahu, S; Dutta, R

    2011-08-01

    The present investigation was carried out to find an efficient chemically assisted procedure for enucleation of goat oocytes related to handmade cloning (HMC) technique. After 22-h in vitro maturation, oocytes were incubated with 0.5 μg/ml demecolcine for 2 h. Cumulus cells were removed by pipetting and vortexing in 0.5 mg/ml hyaluronidase, and zona pellucida were digested with pronase. Oocytes with extrusion cones were subjected to oriented bisection. One-third of the cytoplasm with the extrusion cone was removed with a micro blade. The remaining cytoplasts were used as recipients in HMC. Goat foetal fibroblasts were used as nuclear donors. The overall efficiency measured as the number of cytoplasts obtained per total number of oocytes used was significantly (p < 0.05) higher in chemically assisted handmade enucleation (CAHE) than oriented handmade enucleation without demecolcine (OHE) (80.02 ± 1.292% vs. 72.9 ± 1.00%, respectively, mean ± SEM). The reconstructed and activated embryos were cultured in embryo development medium (EDM) for 7 days. Fusion, cleavage and blastocyst development rate were 71.63 ± 1.95%, 92.94 ± 0.91% and 23.78 ± 3.33% (mean ± SEM), respectively which did not differ significantly from those achieved with random handmade enucleation and OHE. In conclusion, chemically assisted enucleation is a highly efficient and reliable enucleation method for goat HMC which eliminates the need of expensive equipment (inverted fluorescence microscope) and potentially harmful chromatin staining and ultraviolet (UV) irradiation for cytoplast selection. © 2010 Blackwell Verlag GmbH.

  16. Metal-assisted chemical etching of CIGS thin films for grain size analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Chaowei [Research and Development Centre, Hanergy Thin Film Power Group Limited, Chengdu (China); Loi, Huu-Ha; Duong, Anh; Parker, Magdalena [Failure Analysis Department, MiaSole Hi-Tech Corp., Santa Clara, CA (United States)

    2016-09-15

    Grain size of the CIGS absorber is an important monitoring factor in the CIGS solar cell manufacturing. Electron backscatter diffraction (EBSD) analysis is commonly used to perform CIGS grain size analysis in the scanning electron microscope (SEM). Although direct quantification on SEM image using the average grain intercept (AGI) method is faster and simpler than EBSD, it is hardly applicable on CIGS thin films. The challenge is that, not like polycrystalline silicon, to define grain boundaries by selective chemical etching is not easily realizable for the multi-component CIGS alloy. In this Letter, we present direct quantification of CIGS thin film grain size using the AGI method by developing metal-assisted wet chemical etching process to define CIGS grain boundaries. The calculated value is similar to EBSD result. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Renewable platform chemicals from directional microwave-assisted liquefaction coupling stepwise extraction of waste biomass.

    Science.gov (United States)

    Feng, Junfeng; Hse, Chungyun; Yang, Zhongzhi; Wang, Kui; Jiang, Jianchun; Xu, Junming

    2017-11-01

    Directional microwave-assisted liquefaction and stepwise extraction are introduced for producing platform chemicals: aromatics and monosaccharides. When sulfuric acid was used as a catalyst, a 45% monosaccharides yield and a 29% aromatics yield were obtained from bamboo with 0.3g catalyst per 18g methanol and 2g bamboo at 160°C with 10min. Approximately 78-86wt% of the six biomass materials were converted into liquid products. After the stepwise extraction and precipitation process, the yields of monosaccharide derivatives and three phenolic compound fractions were 39-45% and 28-32%, respectively. Monosaccharides from holocellulose collected with a high purity of methyl glycosides were higher than 90%. Aromatic derivatives with different weight-molecular distributions were separated into three fractions with more than 80% phenolics. As their similar chemical properties within each fraction, platform chemicals have great commercial potential for producing high-quality chemicals and biofuels using mild upgrading conditions. Copyright © 2017. Published by Elsevier Ltd.

  18. On water vapour transfer inside frozen packs

    National Research Council Canada - National Science Library

    Heiss, R

    1971-01-01

    In the case of various foodstuffs, irreversible water- vapour transporations within the frozen packages can bring about a distinct quality drop caused by damage to the surface of the material as a result of drying out (freezer burn...

  19. Phase Equilibrium of TiO2 Nanocrystals in Flame-Assisted Chemical Vapor Deposition.

    Science.gov (United States)

    Liu, Changran; Camacho, Joaquin; Wang, Hai

    2017-10-23

    Nano-scale titanium oxide (TiO2) is a material useful for a wide range of applications. In a previous study, we showed that TiO2 nanoparticles of both rutile and anatase crystal phases could be synthesized over the size range of 5 to 20 nm in flame-assisted chemical vapor deposition. While rutile was unexpectedly dominant in oxygen-lean synthesis conditions, anatase is the preferred phase in oxygen-rich gases. The observation is in contrast to the 14 nm rutile-anatase crossover size derived from the existing crystal-phase equilibrium model. In the present work, we made additional measurements over a wider range of synthesis conditions; the results confirm the earlier observations. We propose an improved model for the surface energy that considers the role of oxygen desorption at high temperatures. The model successfully explains the observations made in the current and previous work. The current results provide a useful path to designing flame-assisted chemical vapor deposition of TiO2 nanocrystals with controllable crystal phases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Chemometrics-assisted spectrophotometry method for the determination of chemical oxygen demand in pulping effluent.

    Science.gov (United States)

    Chen, Honglei; Chen, Yuancai; Zhan, Huaiyu; Fu, Shiyu

    2011-04-01

    A new method has been developed for the determination of chemical oxygen demand (COD) in pulping effluent using chemometrics-assisted spectrophotometry. Two calibration models were established by inducing UV-visible spectroscopy (model 1) and derivative spectroscopy (model 2), combined with the chemometrics software Smica-P. Correlation coefficients of the two models are 0.9954 (model 1) and 0.9963 (model 2) when COD of samples is in the range of 0 to 405 mg/L. Sensitivities of the two models are 0.0061 (model 1) and 0.0056 (model 2) and method detection limits are 2.02-2.45 mg/L (model 1) and 2.13-2.51 mg/L (model 2). Validation experiment showed that the average standard deviation of model 2 was 1.11 and that of model 1 was 1.54. Similarly, average relative error of model 2 (4.25%) was lower than model 1 (5.00%), which indicated that the predictability of model 2 was better than that of model 1. Chemometrics-assisted spectrophotometry method did not need chemical reagents and digestion which were required in the conventional methods, and the testing time of the new method was significantly shorter than the conventional ones. The proposed method can be used to measure COD in pulping effluent as an environmentally friendly approach with satisfactory results.

  1. Surface chemical studies of chemical vapour deposited diamond thin films

    CERN Document Server

    Proffitt, S

    2001-01-01

    could not easily be correlated to the bulk film properties. It is suggested that electron emission arises from the graphite component of graphite- diamond grain boundaries that are present in the nanocrystalline films. species. The adsorbed O and Cl species are more strongly bound to the K layer than they are to the diamond substrate, so thermal desorption of K from the K/CI/diamond or K/O/diamond surface results also in the simultaneous loss ofO and Cl. The phosphorus precursor trisdimethylaminophosphine (TDMAP) has a negligible reactive sticking probability on the clean diamond surface. This can be increased by thermal cracking of the gas phase precursor by a heated filament, resulting in non-activated adsorption to produce an adlayer containing a mixture of surface-bound ligands and phosphorus containing species. The ligands were readily lost upon heating, leaving P, some of which was lost from the surface at higher temperatures. Pre-hydrogenation of the diamond surface inhibited the uptake of cracked TDMA...

  2. Microstructural, chemical and textural characterization of ZnO nanorods synthesized by aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Fuentes-Cobas, L.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C. [Centro de Investigación en Materiales Avanzados, S.C., Chihuahua, Chihuahua 31109 (Mexico); Pérez-García, S.A. [Centro de Investigación en Materiales Avanzados, S.C., Unidad Monterrey, Apodaca, Nuevo León 66600 (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, S.C., Chihuahua, Chihuahua 31109 (Mexico)

    2014-12-15

    ZnO nanorods were synthesized by aerosol assisted chemical vapor deposition onto TiO{sub 2} covered borosilicate glass substrates. Deposition parameters were optimized and kept constant. Solely the effect of different nozzle velocities on the growth of ZnO nanorods was evaluated in order to develop a dense and uniform structure. The crystalline structure was characterized by conventional X-ray diffraction in grazing incidence and Bragg–Brentano configurations. In addition, two-dimensional grazing incidence synchrotron radiation diffraction was employed to determine the preferred growth direction of the nanorods. Morphology and growth characteristics analyzed by electron microscopy were correlated with diffraction outcomes. Chemical composition was established by X-ray photoelectron spectroscopy. X-ray diffraction results and X-ray photoelectron spectroscopy showed the presence of wurtzite ZnO and anatase TiO{sub 2} phases. Morphological changes noticed when the deposition velocity was lowered to the minimum, indicated the formation of relatively vertically oriented nanorods evenly distributed onto the TiO{sub 2} buffer film. By coupling two-dimensional X-ray diffraction and computational modeling with ANAELU it was proved that a successful texture determination was achieved and confirmed by scanning electron microscopy analysis. Texture analysis led to the conclusion of a preferred growth direction in [001] having a distribution width Ω = 20° ± 2°. - Highlights: • Uniform and pure single-crystal ZnO nanorods were obtained by AACVD technique. • Longitudinal and transversal axis parallel to the [001] and [110] directions, respectively. • Texture was determined by 2D synchrotron diffraction and electron microscopy analysis. • Nanorods have its [001] direction distributed close to the normal of the substrate. • Angular spread about the preferred orientation is 20° ± 2°.

  3. Inverse metal-assisted chemical etching produces smooth high aspect ratio InP nanostructures.

    Science.gov (United States)

    Kim, Seung Hyun; Mohseni, Parsian K; Song, Yi; Ishihara, Tatsumi; Li, Xiuling

    2015-01-14

    Creating high aspect ratio (AR) nanostructures by top-down fabrication without surface damage remains challenging for III-V semiconductors. Here, we demonstrate uniform, array-based InP nanostructures with lateral dimensions as small as sub-20 nm and AR > 35 using inverse metal-assisted chemical etching (I-MacEtch) in hydrogen peroxide (H2O2) and sulfuric acid (H2SO4), a purely solution-based yet anisotropic etching method. The mechanism of I-MacEtch, in contrast to regular MacEtch, is explored through surface characterization. Unique to I-MacEtch, the sidewall etching profile is remarkably smooth, independent of metal pattern edge roughness. The capability of this simple method to create various InP nanostructures, including high AR fins, can potentially enable the aggressive scaling of InP based transistors and optoelectronic devices with better performance and at lower cost than conventional etching methods.

  4. Plasma-Assisted Mist Chemical Vapor Deposition of Zinc Oxide Films Using Solution of Zinc Acetate

    Science.gov (United States)

    Takenaka, Kosuke; Okumura, Yusuke; Setsuhara, Yuichi

    2013-01-01

    Zinc oxide (ZnO) film deposition has been carried out by plasma-assisted mist chemical vapor deposition (CVD) using a solution of zinc acetate [Zn(CH3COO)2], and the effects of plasma exposure on film properties have been investigated in terms of RF power. With increasing RF power, the results of the X-ray diffraction (XRD) patterns of ZnO films with plasma exposure showed the existence of crystallized ZnO films with plasma exposure. Under this condition, the substrate temperature was as low as 200 °C for a plasma exposure time of 20 min. The surface morphology shown by scanning electron microscopy (SEM) images shows that the ZnO films were textured with round grains, which is attributed to the effect of the use of mist with the precursor.

  5. Low Temperature Metal Free Growth of Graphene on Insulating Substrates by Plasma Assisted Chemical Vapor Deposition.

    Science.gov (United States)

    Muñoz, R; Munuera, C; Martínez, J I; Azpeitia, J; Gómez-Aleixandre, C; García-Hernández, M

    2017-03-01

    Direct growth of graphene films on dielectric substrates (quartz and silica) is reported, by means of remote electron cyclotron resonance plasma assisted chemical vapor deposition r-(ECR-CVD) at low temperature (650°C). Using a two step deposition process- nucleation and growth- by changing the partial pressure of the gas precursors at constant temperature, mostly monolayer continuous films, with grain sizes up to 500 nm are grown, exhibiting transmittance larger than 92% and sheet resistance as low as 900 Ω·sq-1. The grain size and nucleation density of the resulting graphene sheets can be controlled varying the deposition time and pressure. In additon, first-principles DFT-based calculations have been carried out in order to rationalize the oxygen reduction in the quartz surface experimentally observed. This method is easily scalable and avoids damaging and expensive transfer steps of graphene films, improving compatibility with current fabrication technologies.

  6. Bilayer–metal assisted chemical etching of silicon microwire arrays for photovoltaic applications

    Directory of Open Access Journals (Sweden)

    R. W. Wu

    2016-02-01

    Full Text Available Silicon microwires with lateral dimension from 5 μm to 20 μm and depth as long as 20 μm are prepared by bilayer metal assisted chemical etching (MaCE. A bilayer metal configuration (Metal 1 / Metal 2 was applied to assist etching of Si where metal 1 acts as direct catalyst and metal 2 provides mechanical support. Different metal types were investigated to figure out the influence of metal catalyst on morphology of etched silicon. We find that silicon microwires with vertical side wall are produced when we use Ag/Au bilayer, while cone–like and porous microwires formed when Pt/Au is applied. The different micro-/nano-structures in as-etched silicon are demonstrated to be due to the discrepancy of work function of metal catalyst relative to Si. Further, we constructed a silicon microwire arrays solar cells in a radial p–n junction configurations in a screen printed aluminum paste p–doping process.

  7. Novel microwave assisted chemical synthesis of Nd₂Fe₁₄B hard magnetic nanoparticles.

    Science.gov (United States)

    Swaminathan, Viswanathan; Deheri, Pratap Kumar; Bhame, Shekhar Dnyaneswar; Ramanujan, Raju Vijayaraghavan

    2013-04-07

    The high coercivity and excellent energy product of Nd2Fe14B hard magnets have led to a large number of high value added industrial applications. Chemical synthesis of Nd2Fe14B nanoparticles is challenging due to the large reduction potential of Nd(3+) and the high tendency for Nd2Fe14B oxidation. We report the novel synthesis of Nd2Fe14B nanoparticles by a microwave assisted combustion process. The process consisted of Nd-Fe-B mixed oxide preparation by microwave assisted combustion, followed by the reduction of the mixed oxide by CaH2. This combustion process is fast, energy efficient and offers facile elemental substitution. The coercivity of the resulting powders was ∼8.0 kOe and the saturation magnetization was ∼40 emu g(-1). After removal of CaO by washing, saturation magnetization increased and an energy product of 3.57 MGOe was obtained. A range of magnetic properties was obtained by varying the microwave power, reduction temperature and Nd to Fe ratio. A transition from soft to exchange coupled to hard magnetic properties was obtained by varying the composition of NdxFe1-xB8 (x varies from 7% to 40%). This synthesis procedure offers an inexpensive and facile platform to produce exchange coupled hard magnets.

  8. Virucidal efficacy of hydrogen peroxide vapour disinfection.

    Science.gov (United States)

    Tuladhar, E; Terpstra, P; Koopmans, M; Duizer, E

    2012-02-01

    Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. To measure the virucidal efficacy of HPV against respiratory and enteric viruses on materials representing those found in institutions and homes. Poliovirus, human norovirus genogroup II.4 (GII.4), murine norovirus 1, rotavirus, adenovirus and influenza A (H1N1) virus dried on to stainless steel, framing panel and gauze carriers were exposed to HPV 127 ppm for 1h at room temperature in an isolator. Poliovirus was also exposed to HPV at different locations in a room. The virucidal effect was measured by comparing recoverable viral titres against unexposed controls. Polymerase chain reaction was used to evaluate the effect of HPV on viral genome reduction. HPV disinfection resulted in complete inactivation of all viruses tested, characterized by >4 log(10) reduction in infectious particles for poliovirus, rotavirus, adenovirus and murine norovirus on stainless steel and framing panel carriers, and >2 log(10) reduction for influenza A virus on stainless steel and framing panel carriers, and for all viruses on gauze carriers. Complete inactivation of poliovirus was demonstrated at several locations in the room. Reductions in viral genomes were minimal on framing panel and gauze carriers but significant on stainless steel carriers; human norovirus GII.4 genome was most resistant to HPV treatment. HPV could be an effective virucidal against enteric and respiratory viruses contaminating in-house environments. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  9. Microwave assisted conversion of microcrystalline cellulose into value added chemicals using dilute acid catalyst.

    Science.gov (United States)

    Ching, Teck Wei; Haritos, Victoria; Tanksale, Akshat

    2017-02-10

    One of the grand challenges of this century is to transition fuels and chemicals production derived from fossil feedstocks to renewable feedstocks such as cellulosic biomass. Here we describe fast microwave conversion of microcrystalline cellulose (MCC) in water, with dilute acid catalyst to produce valuable platform chemicals. Single 10min microwave assisted treatment was able to convert >60% of MCC, with >50mol% yield of desirable products such as glucose, HMF, furfural and levulinic acid. Recycling of residual MCC with make-up fresh MCC resulted in an overall conversion of >93% after 5 cycles while maintaining >60% conversion in each cycle. Addition of isopropanol (70%v/v) as a co-solvent increased the yields of HMF and levulinic acid. This work shows for the first time proof of concept for complete conversion of recalcitrant microcrystalline cellulose in mild conditions of low temperature, dilute acid and short residence time using energy efficient microwave technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. An Investigation of Tertiary Students' Understanding of Evaporation, Condensation and Vapour Pressure. Research Report

    Science.gov (United States)

    Gopal, Hemant; Kleinsmidt, Jacques; Case, Jennifer; Musonge, Paul

    2004-01-01

    Based on a purposive sample of 15 second-year chemical engineering students, this study investigates students' conceptions of evaporation, condensation and vapour pressure. During individual interviews the students were questioned on three tasks that had been designed around these topics. Qualitative analysis of student responses showed a range of…

  11. An Investigation of Tertiary Students' Understanding of Evaporation, Condensation and Vapour Pressure

    Science.gov (United States)

    Gopal, Hemant; Kleinsmidt, Jacques; Case, Jennifer; Musonge, Paul

    2004-01-01

    Based on a purposive sample of 15 second-year chemical engineering students, this study investigates students' conceptions of evaporation, condensation and vapour pressure. During individual interviews the students were questioned on three tasks that had been designed around these topics. Qualitative analysis of student responses showed a range of…

  12. Temperature-dependent transport mechanisms through PE-CVD coatings: comparison of oxygen and water vapour

    Science.gov (United States)

    Kirchheim, D.; Wilski, S.; Jaritz, M.; Mitschker, F.; Gebhard, M.; Brochhagen, M.; Böke, M.; Benedikt, Jan; Awakowicz, P.; Devi, A.; Hopmann, Ch; Dahlmann, R.

    2017-10-01

    When it comes to thin coatings such as plasma-enhanced chemical vapour deposition or plasma-enhanced atomic layer deposition coatings on substrates of polymeric material, existing models often describe transport through these thin coatings as mainly driven by transport through defects of different sizes. However, temperature-dependent measurements of permeation could not confirm this hypothesis and instead gaseous transport through these thin coatings was found to more likely to occur through the molecular structure. This paper correlates existing transport models with data from oxygen transmission experiments and puts recent investigations for water vapour transmission mechanisms into context for a better understanding of gaseous transport through thin coatings.

  13. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes.

    Science.gov (United States)

    Goniewicz, Maciej Lukasz; Knysak, Jakub; Gawron, Michal; Kosmider, Leon; Sobczak, Andrzej; Kurek, Jolanta; Prokopowicz, Adam; Jablonska-Czapla, Magdalena; Rosik-Dulewska, Czeslawa; Havel, Christopher; Jacob, Peyton; Benowitz, Neal

    2014-03-01

    Electronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e-cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals. Vapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods. We found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9-450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product. Our findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.).

  14. Upper tropospheric water vapour variability over tropical latitudes ...

    Indian Academy of Sciences (India)

    Upper tropospheric water vapour variability over tropical latitudes observed using radiosonde and satellite measurements. Ghouse Basha ... Keywords. Water vapour; radiosonde; satellite measurements. ... National Atmospheric Research Laboratory (NARL), Department of Space, Government of India, Gadanki, PB No. 123 ...

  15. Chemical mimicking of bio-assisted aluminium extraction by Aspergillus niger's exometabolites.

    Science.gov (United States)

    Boriová, Katarína; Urík, Martin; Bujdoš, Marek; Pifková, Ivana; Matúš, Peter

    2016-11-01

    Presence of microorganisms in soils strongly affects mobility of metals. This fact is often excluded when mobile metal fraction in soil is studied using extraction procedures. Thus, the first objective of this paper was to evaluate strain Aspergillus niger's exometabolites contribution on aluminium mobilization. Fungal exudates collected in various time intervals during cultivation were analyzed and used for two-step bio-assisted extraction of alumina and gibbsite. Oxalic, citric and gluconic acids were identified in collected culture media with concentrations up to 68.4, 2.0 and 16.5 mmol L-1, respectively. These exometabolites proved to be the most efficient agents in mobile aluminium fraction extraction with aluminium extraction efficiency reaching almost 2.2%. However, fungal cultivation is time demanding process. Therefore, the second objective was to simplify acquisition of equally efficient extracting agent by chemically mimicking composition of main organic acid components of fungal exudates. This was successfully achieved with organic acids mixture prepared according to medium composition collected on the 12th day of Aspergillus niger cultivation. This mixture extracted similar amounts of aluminium from alumina compared to culture medium. The aluminium extraction efficiency from gibbsite by organic acids mixture was lesser than 0.09% which is most likely because of more rigid mineral structure of gibbsite compared to alumina. The prepared organic acid mixture was then successfully applied for aluminium extraction from soil samples and compared to standard single step extraction techniques. This showed there is at least 2.9 times higher content of mobile aluminium fraction in soils than it was previously considered, if contribution of microbial metabolites is considered in extraction procedures. Thus, our contribution highlights the significance of fungal metabolites in aluminium extraction from environmental samples, but it also simplifies the extraction

  16. Microstructural and frictional control of diamond-like carbon films deposited on acrylic rubber by plasma assisted chemical vapor deposition

    NARCIS (Netherlands)

    Martinez-Martinez, D.; Schenkel, M.; Pei, Y.T.; Hosson, J.Th.M. De

    2011-01-01

    In this paper we concentrate on the microstructure of diamond-like carbon films prepared by plasma assisted chemical vapor deposition on acrylic rubber. The temperature variation produced by the ion impingement during plasma cleaning and subsequent film deposition was monitored and controlled as a

  17. Surfactant-Assisted in situ Chemical Etching for the General Synthesis of ZnO Nanotubes Array.

    Science.gov (United States)

    Wang, Hongqiang; Li, Ming; Jia, Lichao; Li, Liang; Wang, Guozhong; Zhang, Yunxia; Li, Guanghai

    2010-04-24

    In this paper, a general low-cost and substrate-independent chemical etching strategy is demonstrated for the synthesis of ZnO nanotubes array. During the chemical etching, the nanotubes array inherits many features from the preformed nanorods array, such as the diameter, size distribution, and alignment. The preferential etching along c axis and the surfactant protection to the lateral surfaces are considered responsible for the formation of ZnO nanotubes. This surfactant-assisted chemical etching strategy is highly expected to advance the research in the ZnO nanotube-based technology.

  18. Surfactant-Assisted in situ Chemical Etching for the General Synthesis of ZnO Nanotubes Array

    Directory of Open Access Journals (Sweden)

    Wang Hongqiang

    2010-01-01

    Full Text Available Abstract In this paper, a general low-cost and substrate-independent chemical etching strategy is demonstrated for the synthesis of ZnO nanotubes array. During the chemical etching, the nanotubes array inherits many features from the preformed nanorods array, such as the diameter, size distribution, and alignment. The preferential etching along c axis and the surfactant protection to the lateral surfaces are considered responsible for the formation of ZnO nanotubes. This surfactant-assisted chemical etching strategy is highly expected to advance the research in the ZnO nanotube-based technology.

  19. Water vapour loss measurements on human skin.

    NARCIS (Netherlands)

    Valk, Petrus Gerardus Maria van der

    1984-01-01

    In this thesis, the results of a series of investigations into the barrier function of human skin are presented. In these investigations, the barrier function was assessed by water vapour loss measurements of the skin using a method based on gradient estimation.... Zie: Summary and conclusions

  20. Developments in vapour cloud explosion blast modeling

    NARCIS (Netherlands)

    Mercx, W.P.M.; Berg, A.C. van den; Hayhurst, C.J.; Robertson, N.J.; Moran, K.C.

    2000-01-01

    TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be

  1. Development of aerosol assisted chemical vapor deposition for thin film fabrication

    Science.gov (United States)

    Maulana, Dwindra Wilham; Marthatika, Dian; Panatarani, Camellia; Mindara, Jajat Yuda; Joni, I. Made

    2016-02-01

    Chemical vapor deposition (CVD) is widely used to grow a thin film applied in many industrial applications. This paper report the development of an aerosol assisted chemical vapor deposition (AACVD) which is one of the CVD methods. Newly developed AACVD system consists of a chamber of pyrex glass, two wire-heating elements placed to cover pyrex glass, a substrate holder, and an aerosol generator using an air brush sprayer. The temperature control system was developed to prevent condensation on the chamber walls. The control performances such as the overshoot and settling time were obtained from of the developed temperature controller. Wire-heating elements were controlled at certain setting value to heat the injected aerosol to form a thin film in the substrate. The performance of as-developed AACVD system tested to form a thin film where aerosol was sprayed into the chamber with a flow rate of 7 liters/minutes, and vary in temperatures and concentrations of precursor. The temperature control system have an overshoot around 25 °C from the desired set point temperature, very small temperature ripple 2 °C and a settling time of 20 minutes. As-developed AACVD successfully fabricated a ZnO thin film with thickness of below 1 µm. The performances of system on formation of thin films influenced by the generally controlled process such as values of setting temperature and concentration where the aerosol flow rate was fixed. Higher temperature was applied, the more uniform ZnO thin films were produced. In addition, temperature of the substrate also affected on surface roughness of the obtained films, while concentration of ZnO precursor determined the thickness of produce films. It is concluded that newly simple AACVD can be applied to produce a thin film.

  2. Condensation of water vapour on moss-dominated biological soil ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 123; Issue 2 ... Condensation; water vapour; desert ecosystem; moss; biological soil crust. Abstract. Characteristics of water vapour condensation, including the onset, duration, and amount of water vapour condensation on moss-dominated biological soil crust ...

  3. estimation of precipitable water vapour in nigeria using surface ...

    African Journals Online (AJOL)

    USER

    affects the climate and weather systems through its effect on the atmospheric temperature and energy transport (Garrison, 1992; Follette et al.,. 2008). A very important measure of the atmospheric water vapour is the precipitable water vapour. (PWV). Precipitable Water Vapour (PWV) is a measure of the total amount of water ...

  4. Antireflection subwavelength structures based on silicon nanowires arrays fabricated by metal-assisted chemical etching

    Science.gov (United States)

    Li, Bin; Niu, Gao; Yi, Yong; Zhou, Xiu-wen; Liu, Xu-dong; Sun, Lai-xi; Wang, Chao-yang

    2017-11-01

    In this paper, we have obtained a series of large-area and different diameters nanosphere lithography (NSL) to obtain the required silicon nanowires (SiNWs) arrays. The single-crystalline SiNWs have been presented by combining nanosphere lithography (NSL) and metal-assisted chemical etching (MACE). The period of SiNW arrays can be controlled by adjusting the original diameter of polystyrene nanosphere (PSs) and the etching time during the NSL process. The special SiNWs structure obtained can be demonstrated to be significant for improving the antireflection properties of silicon substrate. The results show that SiNW arrays with various parameters, such as diameter, distance and height can be obtained by controlling the key etching parameter during the MACE process, which are important to obtain the structures of different parameters to adapt an appropriate value to decrease the light scattering. For a wide wavelength range of 300-1200 nm, the reflectance is below 10% or less, which is due to an ultra-high surface area. Especially, the reflectance of antireflection structure (ARS) surface reduces below 1% over a wavelength range of 300-400 nm. Furthermore, the silicon nanowire (SiNW) arrays with highly efficient antireflection obtained by MACE exhibit different surface roughness from the bottom to the top part of SiNWs by high resolution images, which is benefit for further improving the ARS of SiNWs.

  5. Growth mechanism of long aligned multiwall carbon nanotube arrays by water-assisted chemical vapor deposition.

    Science.gov (United States)

    Yun, YeoHeung; Shanov, Vesselin; Tu, Yi; Subramaniam, Srinivas; Schulz, Mark J

    2006-11-30

    Highly aligned arrays of multiwalled carbon nanotube (MWCNT) on layered Si substrates have been synthesized by chemical vapor deposition (CVD). The effect of the substrate design and the process parameters on the growth mechanism were studied. Adding water vapor to the reaction gas mixture of hydrogen and ethylene enhanced the growth which led to synthesis of longer CNT arrays with high density. Environmental scanning electron microscopy (ESEM), energy-dispersive spectroscopy (EDS), and atomic force microscopy (AFM) were used to analyze the CNT morphology and composition. Quadrupole mass spectroscopy (QMS) provided in-situ information on the gas spices within the reaction zone. On the basis of results, we verified the top growth mechanism and evaluated the reason of decline and stoppage of the CNT growth after extended period of deposition. Multilayered Si substrates with a top film of Al2O3, having appropriate roughness, provide favorable conditions to form catalyst islands with uniform distribution and size. Using water-assisted CVD process and optimized substrate design, our group succeeded to grow vertically aligned, patterned MWCNT up to 4-mm long. The arrays were of high purity and weak adhesion which allowed to be peeled off easily from the substrate.

  6. Water-assisted growth of graphene on carbon nanotubes by the chemical vapor deposition method.

    Science.gov (United States)

    Feng, Jian-Min; Dai, Ye-Jing

    2013-05-21

    Combining carbon nanotubes (CNTs) with graphene has been proved to be a feasible method for improving the performance of graphene for some practical applications. This paper reports a water-assisted route to grow graphene on CNTs from ferrocene and thiophene dissolved in ethanol by the chemical vapor deposition method in an argon flow. A double injection technique was used to separately inject ethanol solution and water for the preparation of graphene/CNTs. First, CNTs were prepared from ethanol solution and water. The injection of ethanol solution was suspended and water alone was injected into the reactor to etch the CNTs. Thereafter, ethanol solution was injected along with water, which is the key factor in obtaining graphene/CNTs. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Raman scattering analyses confirmed that the products were the hybrid materials of graphene/CNTs. X-ray photo-electron spectroscopy analysis showed the presence of oxygen rich functional groups on the surface of the graphene/CNTs. Given the activity of the graphene/CNT surface, CdS quantum dots adhered onto it uniformly through simple mechanical mixing.

  7. Microwave plasma-assisted chemical vapor deposition of porous carbon film as supercapacitive electrodes

    Science.gov (United States)

    Wu, Ai-Min; Feng, Chen-Chen; Huang, Hao; Paredes Camacho, Ramon Alberto; Gao, Song; Lei, Ming-Kai; Cao, Guo-Zhong

    2017-07-01

    Highly porous carbon film (PCF) coated on nickel foam was prepared successfully by microwave plasma-assisted chemical vapor deposition (MPCVD) with C2H2 as carbon source and Ar as discharge gas. The PCF is uniform and dense with 3D-crosslinked nanoscale network structure possessing high degree of graphitization. When used as the electrode material in an electrochemical supercapacitor, the PCF samples verify their advantageous electrical conductivity, ion contact and electrochemical stability. The test results show that the sample prepared under 1000 W microwave power has good electrochemical performance. It displays the specific capacitance of 62.75 F/g at the current density of 2.0 A/g and retains 95% of its capacitance after 10,000 cycles at the current density of 2.0 A/g. Besides, its near-rectangular shape of the cyclic voltammograms (CV) curves exhibits typical character of an electric double-layer capacitor, which owns an enhanced ionic diffusion that can fit the requirements for energy storage applications.

  8. Etchant wettability in bulk micromachining of Si by metal-assisted chemical etching

    Science.gov (United States)

    Yoon, Sung-Soo; Lee, Yeong Bahl; Khang, Dahl-Young

    2016-05-01

    Wet bulk micromachining of Si by metal-assisted chemical etching (MaCE) has successfully been demonstrated. Based on the mechanism of defective etching results from Ag and Au metal catalyst experiments, the wettability of etchant solution, in addition to metal type, has been found to have profound effect on the etching process. Addition of low surface tension co-solvent, ethanol in this work, into conventional etchant formulation has enabled complete wetting of etchant on surface, which prevents hydrogen bubble attachment on sample surface during the etching. The complete elimination of bubble attachment guarantees very uniform etch rate on all over the sample surface, and thus prevents premature fragmentation/rupture of catalyst metal layer. Under the optimized etching conditions, the MaCE could be done for up to 12 h without any noticeable film rupture and thus etching defects. Thanks to very smooth surface of the etched patterns, conformal contact and direct bonding of elastomer on such surface has been easily accomplished. The method demonstrated here can pave the way for application of simple, low-cost MaCE process in the bulk micromachining of Si for various applications.

  9. Surface passivation of silicon nanowires based metal nano-particle assisted chemical etching for photovoltaic applications

    Science.gov (United States)

    Ben Rabha, Mohamed; Khezami, Lotfi; Jemai, Abdelbasset Bessadok; Alhathlool, Raed; Ajbar, Abdelhamid

    2017-03-01

    Metal Nano-particle Assisted Chemical Etching (MNpACE) is an extraordinary developed wet etching method for producing uniform semiconductor nanostructure (silicon nanowires) from patterned metallic film on crystalline silicon surface. The metal films facilitate the etching in HF and H2O2 solution and produce silicon nanowires (SiNWs).The creation of different SiNWs morphologies by changing the etching time and its effects on optical and optoelectronic properties was investigated. The combination effect of formed SiNWs and stain etching treatment in acid (HF/HNO3/H2O) solution on the surface morphology of Si wafers as well as on the optical and optoelectronic properties especially a PL response at 640 nm are presented. As a results, the effective lifetime (τeff) and surface recombination velocity (Seff) evolution of SiNWs after stain etching treatment showed significant improvements and less than 1% reflectance was achieved over the wavelength range of 400-800 nm and more than 36% reduction was observed compared to untreated surface. It has, thus, been demonstrated that all these factors may lead to improved energy efficiency from 8% to nearly 14.2% for a cell with SiNWs treated in acid (HF/HNO3/H2O) solution.

  10. Nanostructured GaAs solar cells via metal-assisted chemical etching of emitter layers.

    Science.gov (United States)

    Song, Yunwon; Choi, Keorock; Jun, Dong-Hwan; Oh, Jungwoo

    2017-10-02

    GaAs solar cells with nanostructured emitter layers were fabricated via metal-assisted chemical etching. Au nanoparticles produced via thermal treatment of Au thin films were used as etch catalysts to texture an emitter surface with nanohole structures. Epi-wafers with emitter layers 0.5, 1.0, and 1.5 um in thickness were directly textured and a window layer removal process was performed before metal catalyst deposition. A nanohole-textured emitter layer provides effective light trapping capabilities, reducing the surface reflection of a textured solar cell by 11.0%. However, because the nanostructures have high surface area to volume ratios and large numbers of defects, various photovoltaic properties were diminished by high recombination losses. Thus, we have studied the application of nanohole structures to GaAs emitter solar cells and investigated the cells' antireflection and photovoltaic properties as a function of the nanohole structure and emitter thickness. Due to decreased surface reflection and improved shunt resistance, the solar cell efficiency increased from 4.25% for non-textured solar cells to 7.15% for solar cells textured for 5 min.

  11. The nature of resonance-assisted hydrogen bonds: a quantum chemical topology perspective.

    Science.gov (United States)

    Guevara-Vela, José Manuel; Romero-Montalvo, Eduardo; Costales, Aurora; Pendás, Ángel Martín; Rocha-Rinza, Tomás

    2016-10-14

    Resonance Assisted Hydrogen Bonds (RAHBs) are particularly strong H-Bonds (HBs) which are relevant in several fields of chemistry. The traditional explanation for the occurrence of these HBs is built on mesomeric structures evocative of electron delocalisation in the system. Nonetheless, there are several theoretical studies which have found no evidence of such electron delocalisation. We considered the origin of RAHBs by employing Quantum Chemical Topology tools, more specifically, the Quantum Theory of Atoms in Molecules (QTAIM) and the Interacting Quantum Atoms energy partition. Our results indicate that the π-conjugated bonds allow for a larger adjustment of electron density throughout the H-bonded system as compared with non-conjugated carbonyl molecules. This rearrangement of charge distribution is a response to the electric field due to the H atom involved in the hydrogen bonding of the considered compounds. As opposed to the usual description of RAHB interactions, these HBs lead to a larger electron localisation in the system, and concomitantly to larger QTAIM charges which in turn lead to stronger electrostatic, polarization and charge transfer components of the interaction. Overall, the results presented here offer a new perspective on the cause of strengthening of these important interactions.

  12. Ultrasound assisted method to increase soluble chemical oxygen demand (SCOD) of sewage sludge for digestion.

    Science.gov (United States)

    Grönroos, Antti; Kyllönen, Hanna; Korpijärvi, Kirsi; Pirkonen, Pentti; Paavola, Teija; Jokela, Jari; Rintala, Jukka

    2005-01-01

    The aim of this study was to clarify the possibilities to increase the amount of soluble chemical oxygen demand (SCOD) and methane production of sludge using ultrasound technologies with and without oxidising agents. The study was done using multivariate data analyses. The most important factors affected were discovered. Ultrasonically assisted disintegration increased clearly the amount of SCOD of sludge. Also more methane was produced from treated sludge in anaerobic batch assays compared to the sludge with no ultrasonic treatment. Multivariate data analysis showed that ultrasonic power, dry solid content of sludge (DS), sludge temperature and ultrasonic treatment time have the most significant effect on the disintegration. It was also observed that in the reactor studied energy efficiency with high ultrasound power together with short treatment time was higher than with low ultrasound power with long treatment time. When oxidising agents were used together with ultrasound no increase in SCOD was achieved compared the ultrasonic treatment alone and only a slight increase in total organic carbon of sludge was observed. However, no enhancement in methane production was observed when using oxidising agents together with ultrasound compared the ultrasonic treatment alone. Ultrasound propagation is an important factor in ultrasonic reactor scale up. Ultrasound efficiency rose linearly with input power in sludge at small distances from the transducer. Instead, ultrasound efficiency started even to decrease with input power at long distances from the transducer.

  13. Microwave-assisted chemical bath deposition of nanostructured ZnO particles.

    Science.gov (United States)

    Chaudhuri, Tapas K; Kothari, Anjana

    2009-09-01

    Microwave-assisted chemical bath deposition (MACBD) is an emerging technique for quick preparation of nanoscale and nanostructured particles. We report a simple and rapid process for synthesis of nanostructured ZnO particles by MACBD from aqueous solution of tetra ammonium zinc hydroxide. The effect of Zn+2 concentrations (0.025 to 0.2 mole/L), pH (10 to 11) and base on morphology and composition of deposited particles has been studied. Precursor solution (PS) containing 0.12 mole/L Zn+2 at pH approximately 10.3 and NaOH yielded ZnO flowers of sizes 1-2 /tm. The ZnO flowers typically consist of a central round rod surrounded by six tapered petals. Other PSs generated mixture of ZnO flowers and Zn(OH)2 rhombic particles. The results are explained on the basis of thermal decomposition of tetra ammonium zinc complex to ZnO or Zn(OH)2.

  14. Tunable Surface Structuration of Silicon by Metal Assisted Chemical Etching with Pt Nanoparticles under Electrochemical Bias.

    Science.gov (United States)

    Torralba, Encarnación; Le Gall, Sylvain; Lachaume, Raphaël; Magnin, Vincent; Harari, Joseph; Halbwax, Mathieu; Vilcot, Jean-Pierre; Cachet-Vivier, Christine; Bastide, Stéphane

    2016-11-16

    An in-depth study of metal assisted chemical etching (MACE) of p-type c-Si in HF/H2O2 aqueous solutions using Pt nanoparticles as catalysts is presented. Combination of cyclic voltammetry, open circuit measurements, chronoamperometry, impedance spectroscopy, and 2D band bending modeling of the metal/semiconductor/electrolyte interfaces at the nanoscale and under different etching conditions allows gaining physical insights into this system. Additionally, in an attempt to mimic the etching conditions, the modeling has been performed with a positively biased nanoparticle buried in the Si substrate. Following these findings, the application of an external polarization during etching is introduced as a novel efficient approach for achieving straightforward control of the pore morphology by acting upon the band bending at the Si/electrolyte junction. In this way, nanostructures ranging from straight mesopores to cone-shaped macropores are obtained as the Si sample is biased from negative to positive potentials. Remarkably, macroscopic cone-shaped pores in the 1-5 μm size range with a high aspect ratio (L/W ∼ 1.6) are obtained by this method. This morphology leads to a reduction of the surface reflectance below 5% over the entire VIS-NIR domain, which outperforms macrostructures made by state of the art texturization techniques for Si solar cells.

  15. Plasma-Assisted Mist Chemical Vapor Deposition of Zinc Oxide Films for Flexible Electronics

    Science.gov (United States)

    Takenaka, Kosuke; Uchida, Giichiro; Setsuhara, Yuichi

    2015-09-01

    Plasma-assisted mist chemical vapor deposition of ZnO films was performed for transparent conductive oxide formation of flexible electronics. In this study, ZnO films deposition using atmospheric-pressure He plasma generated by a micro-hollow cathode-type plasma source has been demonstrated. To obtain detail information according to generation of species in the plasma, the optical emission spectra of the atmospheric pressure He plasma with and without mist were measured. The result without mist shows considerable emissions of He lines, emissions attributed to the excitation and dissociation of air including N2 and O2 (N, O, and NO radials, and N2 molecule; N2 second positive band and first positive band), while the results with mist showed strong emissions attributed to the dissociation of H2O (OH and H radicals). The deposition of ZnO films was performed using atmospheric-pressure He plasma. The XRD patterns showed no crystallization of the ZnO films irradiated with pure He. On the other hand, the ZnO film crystallized with the irradiation with He/O2 mixture plasma. These results indicate that the atmospheric-pressure He/O2 mixture plasma has sufficient reactivity necessary for the crystallization of ZnO films at room temperature. This work was supported partly by The Grant-in-Aid for Scientific Research (KAKENHI) (Grant-in-Aid for Scientific Research(C)) from the Japan Society for the Promotion of Science (JSPS).

  16. Laser-assisted chemical vapor deposition setup for fast synthesis of graphene patterns

    Science.gov (United States)

    Zhang, Chentao; Zhang, Jianhuan; Lin, Kun; Huang, Yuanqing

    2017-05-01

    An automatic setup based on the laser-assisted chemical vapor deposition method has been developed for the rapid synthesis of graphene patterns. The key components of this setup include a laser beam control and focusing unit, a laser spot monitoring unit, and a vacuum and flow control unit. A laser beam with precision control of laser power is focused on the surface of a nickel foil substrate by the laser beam control and focusing unit for localized heating. A rapid heating and cooling process at the localized region is induced by the relative movement between the focalized laser spot and the nickel foil substrate, which causes the decomposing of gaseous hydrocarbon and the out-diffusing of excess carbon atoms to form graphene patterns on the laser scanning path. All the fabrication parameters that affect the quality and number of graphene layers, such as laser power, laser spot size, laser scanning speed, pressure of vacuum chamber, and flow rates of gases, can be precisely controlled and monitored during the preparation of graphene patterns. A simulation of temperature distribution was carried out via the finite element method, providing a scientific guidance for the regulation of temperature distribution during experiments. A multi-layer graphene ribbon with few defects was synthesized to verify its performance of the rapid growth of high-quality graphene patterns. Furthermore, this setup has potential applications in other laser-based graphene synthesis and processing.

  17. Electrochemical nanoimprint lithography: when nanoimprint lithography meets metal assisted chemical etching.

    Science.gov (United States)

    Zhang, Jie; Zhang, Lin; Han, Lianhuan; Tian, Zhao-Wu; Tian, Zhong-Qun; Zhan, Dongping

    2017-06-08

    The functional three dimensional micro-nanostructures (3D-MNS) play crucial roles in integrated and miniaturized systems because of the excellent physical, mechanical, electric and optical properties. Nanoimprint lithography (NIL) has been versatile in the fabrication of 3D-MNS by pressing thermoplastic and photocuring resists into the imprint mold. However, direct nanoimprint on the semiconductor wafer still remains a great challenge. On the other hand, considered as a competitive fabrication method for erect high-aspect 3D-MNS, metal assisted chemical etching (MacEtch) can remove the semiconductor by spontaneous corrosion reaction at the metal/semiconductor/electrolyte 3-phase interface. Moreover, it was difficult for MacEtch to fabricate multilevel or continuously curved 3D-MNS. The question of the consequences of NIL meeting the MacEtch is yet to be answered. By employing a platinum (Pt) metalized imprint mode, we demonstrated that using electrochemical nanoimprint lithography (ECNL) it was possible to fabricate not only erect 3D-MNS, but also complex 3D-MNS with multilevel stages with continuously curved surface profiles on a gallium arsenide (GaAs) wafer. A concave microlens array with an average diameter of 58.4 μm and height of 1.5 μm was obtained on a ∼1 cm(2)-area GaAs wafer. An 8-phase microlens array was fabricated with a minimum stage of 57 nm and machining accuracy of 2 nm, presenting an excellent optical diffraction property. Inheriting all the advantages of both NIL and MacEtch, ECNL has prospective applications in the micro/nano-fabrications of semiconductors.

  18. Light-emitting silicon nanowires obtained by metal-assisted chemical etching

    Science.gov (United States)

    Irrera, Alessia; Josè Lo Faro, Maria; D'Andrea, Cristiano; Alessio Leonardi, Antonio; Artoni, Pietro; Fazio, Barbara; Picca, Rosaria Anna; Cioffi, Nicola; Trusso, Sebastiano; Franzò, Giorgia; Musumeci, Paolo; Priolo, Francesco; Iacona, Fabio

    2017-04-01

    This review reports on a new process for the synthesis of Si nanowires (NWs), based on the wet etching of Si substrates assisted by a thin metal film. The approach exploits the thickness-dependent morphology of the metal layers to define uncovered nanometric Si regions, which behave as precursor sites for the formation of very dense (up to 1 × 1012 NW cm-2) arrays of long (up to several μm) and ultrathin (diameter of 5-9 nm) NWs. Intense photoluminescence (PL) peaks, characterized by maxima in the 640-750 nm range and by an external quantum efficiency of 0.5%, are observed when the Si NWs are excited at room temperature. The spectra show a blueshift if the size of the NW is decreased, in agreement with the occurrence of quantum confinement effects. The same etching process can be used to obtain ultrathin Si/Ge NWs from a Si/Ge multi-quantum well. The Si/Ge NWs exhibit—in addition to the Si-related PL peak—a signal at about 1240 nm due to Ge nanostructures. The huge surface area of the Si NW arrays can be exploited for sensing and analytical applications. The dependence of the PL intensity on the chemical composition of the surface indeed suggests interesting perspectives for the detection of gaseous molecules. Moreover, Si NWs decorated with Ag nanoparticles can be effectively employed in the interference-free laser desorption-ionization mass spectrometry of low-molecular-weight analytes. A device based on conductive Si NWs, showing intense and stable electroluminescence at an excitation voltage as low as 2 V, is also presented. The unique features of the proposed synthesis (the process is cheap, fast, maskless and compatible with Si technology) and the unusual optical properties of the material open the route towards new and unexpected perspectives for semiconductor NWs in photonics.

  19. Microwave-assisted chemical insertion: a rapid technique for screening cathodes for Mg-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kaveevivitchai, Watchareeya; Huq, Ashfia; Manthiram, Arumugam

    2016-12-19

    We report an ultrafast microwave-assisted solvothermal method for chemical insertion of Mg2+ ions into host materials using magnesium acetate [Mg(CH3COO)2] as a metal-ion source and diethylene glycol (DEG) as a reducing agent. For instance, up to 3 Mg ions per formula unit of a microporous host framework Mo2.5+yVO9+z could be inserted in as little as 30 min at 170–195 °C in air. This process is superior to the traditional method which involves the use of organometallic reagents, such as di-n-butylmagnesium [(C4H9)2Mg] and magnesium bis(2,6-di-tert-butylphenoxide) [Mg-(O-2,6-But2C6H3)2], and requires an inert atmosphere with extremely long reaction times. Considering the lack of robust electrolytes for Mg-ion batteries, this facile approach can be readily used as a rapid screening technique to identify potential Mg-ion electrode hosts without the necessity of fabricating electrodes and assembling electrochemical cells. Due to the mild reaction conditions, the overall structure and morphology of the Mg-ion inserted products are maintained and the compounds can be used successfully as a cathode in Mg-ion batteries. The combined synchrotron X-ray and neutron diffraction Rietveld analysis reveals the structure of the Mg-inserted compounds and gives an insight into the interactions between the Mg ions and the open-tunnel host framework.

  20. Interactions of fission product vapours with aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Benson, C.G.; Newland, M.S. [AEA Technology, Winfrith (United Kingdom)

    1996-12-01

    Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350{sup o}C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs.

  1. Effect of ultrasound-assisted freezing on the physico-chemical properties and volatile compounds of red radish.

    Science.gov (United States)

    Xu, Bao-Guo; Zhang, Min; Bhandari, Bhesh; Cheng, Xin-Feng; Islam, Md Nahidul

    2015-11-01

    Power ultrasound, which can enhance nucleation rate and crystal growth rate, can also affect the physico-chemical properties of immersion frozen products. In this study, the influence of slow freezing (SF), immersion freezing (IF) and ultrasound-assisted freezing (UAF) on physico-chemical properties and volatile compounds of red radish was investigated. Results showed that ultrasound application significantly improved the freezing rate; the freezing time of ultrasound application at 0.26 W/cm(2) was shorten by 14% and 90%, compared to IF and SF, respectively. UAF products showed significant (pfreezing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Antibacterial properties and chemical characterization of the essential oils from summer savory extracted by microwave-assisted hydrodistillation

    OpenAIRE

    Rezvanpanah, Shila; Rezaei, Karamatollah; Golmakani, Mohammad-Taghi; Razavi, Seyyed Hadi

    2011-01-01

    Antibacterial properties and chemical characterization of the essential oils from summer savory (Satureja hortensis) extracted by microwave-assisted hydrodistillation (MAHD) were compared with those of the essential oils extracted using the traditional hydrodistillation (HD) method. While MAHD at 660 W required half as much time as HD needed, similar antibacterial efficacies were found from the essential oils obtained by the two extraction methods on two food pathogens (Staphylococcus aureus,...

  3. Material design of plasma-enhanced chemical vapour deposition SiCH films for low-k cap layers in the further scaling of ultra-large-scale integrated devices-Cu interconnects

    Directory of Open Access Journals (Sweden)

    Hideharu Shimizu, Shuji Nagano, Akira Uedono, Nobuo Tajima, Takeshi Momose and Yukihiro Shimogaki

    2013-01-01

    Full Text Available Cap layers for Cu interconnects in ultra-large-scale integrated devices (ULSIs, with a low dielectric constant (k-value and strong barrier properties against Cu and moisture diffusion, are required for the future further scaling of ULSIs. There is a trade-off, however, between reducing the k-value and maintaining strong barrier properties. Using quantum mechanical simulations and other theoretical computations, we have designed ideal dielectrics: SiCH films with Si–C2H4–Si networks. Such films were estimated to have low porosity and low k; thus they are the key to realizing a cap layer with a low k and strong barrier properties against diffusion. For fabricating these ideal SiCH films, we designed four novel precursors: isobutyl trimethylsilane, diisobutyl dimethylsilane, 1, 1-divinylsilacyclopentane and 5-silaspiro [4,4] noname, based on quantum chemical calculations, because such fabrication is difficult by controlling only the process conditions in plasma-enhanced chemical vapor deposition (PECVD using conventional precursors. We demonstrated that SiCH films prepared using these newly designed precursors had large amounts of Si–C2H4–Si networks and strong barrier properties. The pore structure of these films was then analyzed by positron annihilation spectroscopy, revealing that these SiCH films actually had low porosity, as we designed. These results validate our material and precursor design concepts for developing a PECVD process capable of fabricating a low-k cap layer.

  4. First detection of tidal behaviour in polar mesospheric water vapour by ground based microwave spectroscopy

    Directory of Open Access Journals (Sweden)

    K. Hallgren

    2012-04-01

    Full Text Available Mesospheric water vapour has been observed above ALOMAR in northern Norway (69° N 16° E by our group since 1995 using a 22 GHz ground based microwave spectrometer. A new instrument with higher sensitivity, providing a much better time resolution especially in the upper mesosphere, was installed in May 2008. The time resolution is high enough to provide observations of daily variations in the water vapour mixing ratio. We present the first ground based detections of tidal behaviour in the polar middle atmospheric water vapour distribution.

    Diurnal and semidiurnal variations of water vapour have been observed and due to the long chemical lifetime of water they are assumed to be caused by changing wind patterns which transport water-rich or poor air into the observed region. The detected tidal behaviour does not follow any single other dynamical field but is instead assumed to be a result of the different wind components.

    Both the diurnal and semidiurnal amplitude and phase components are resolved. The former shows a stable seasonal behaviour consistent with earlier observations of wind fields and model calculations, whereas the latter appears more complex and no regular behaviour has so far been observed.

  5. Formation and Yield of Multi-Walled Carbon Nanotubes Synthesized via Chemical Vapour Deposition Routes Using Different Metal-Based Catalysts of FeCoNiAl, CoNiAl and FeNiAl-LDH

    Directory of Open Access Journals (Sweden)

    Mohd Zobir Hussein

    2014-11-01

    Full Text Available Multi-walled carbon nanotubes (MWCNTs were prepared via chemical vapor deposition (CVD using a series of different catalysts, derived from FeCoNiAl, CoNiAl and FeNiAl layered double hydroxides (LDHs. Catalyst-active particles were obtained by calcination of LDHs at 800 °C for 5 h. Nitrogen and hexane were used as the carrier gas and carbon source respectively, for preparation of MWCNTs using CVD methods at 800 °C. MWCNTs were allowed to grow for 30 min on the catalyst spread on an alumina boat in a quartz tube. The materials were subsequently characterized through X-ray diffraction, Fourier transform infrared spectroscopy, surface area analysis, field emission scanning electron microscopy and transmission electron microscopy. It was determined that size and yield of MWCNTs varied depending on the type of LDH catalyst precursor that is used during synthesis. MWCNTs obtained using CoNiAl-LDH as the catalyst precursor showed smaller diameter and higher yield compared to FeCoNiAl and FeNiAl LDHs.

  6. Variability of water vapour in the Arctic stratosphere

    Science.gov (United States)

    Thölix, Laura; Backman, Leif; Kivi, Rigel; Karpechko, Alexey Yu.

    2016-04-01

    This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry transport model simulation covering the years 1990-2014 is compared to observations (satellite and frost point hygrometer soundings), and the sources of stratospheric water vapour are studied. In the simulations, the Arctic water vapour shows decadal variability with a magnitude of 0.8 ppm. Both observations and the simulations show an increase in the water vapour concentration in the Arctic stratosphere after the year 2006, but around 2012 the concentration started to decrease. Model calculations suggest that this increase in water vapour is mostly explained by transport-related processes, while the photochemically produced water vapour plays a relatively smaller role. The increase in water vapour in the presence of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ice polar stratospheric clouds (PSCs) in the Arctic vortex. We perform a case study of ice PSC formation focusing on January 2010 when the polar vortex was unusually cold and allowed large-scale formation of PSCs. At the same time a large-scale persistent dehydration was observed. Ice PSCs and dehydration observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT (Lapland Atmosphere-Biosphere facility) atmospheric measurement campaign were well reproduced by the model. In particular, both the observed and simulated decrease in water vapour in the dehydration layer was up to 1.5 ppm.

  7. Water vapour measurements during POLINAT 1

    Energy Technology Data Exchange (ETDEWEB)

    Ovarlez, J.; Ovarlez, H. [Centre National de la Recherche Scientifique, 91 - Palaiseau (France). Lab. de Meteorologie Dynamique

    1997-12-31

    The POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor)1 experiment has been performed within the framework of the Environment Programme of the Commission of the European Community. It was devoted to the study of the pollution from aircraft in the North Atlantic flight corridor, in order to investigate the impact of pollutants emitted by aircraft on the concentrations of ozone and other trace gases in the upper troposphere and lower stratosphere. For that experiment the water vapour content was measured with a frost-point hygrometer on board of the DLR Falcon research aircraft. This instrument is described, and some selected results are given. (author) 19 refs.

  8. Trivalent manganese as an environmentally friendly oxidizing reagent for microwave- and ultrasound-assisted chemical oxygen demand determination.

    Science.gov (United States)

    Domini, Claudia E; Vidal, Lorena; Canals, Antonio

    2009-06-01

    In the present work manganese(III) has been used as oxidant and microwave radiation and ultrasound energy have been assessed to speed up and to improve the efficiency of digestion step for the determination of chemical oxygen demand (COD). Microwave (MW) and ultrasound-assisted COD determination methods have been optimized by means of experimental design and the optimum conditions are: 40psi pressure, 855W power and 1min irradiation time; and 90% of maximum nominal power (180W), 0.9s (s(-1)) cycles and 1min irradiation time for microwaves and ultrasound, respectively. Chloride ion interference is removed as hydrochloric acid gas from acidified sample solutions at 150 degrees C in a closed reaction tube and captured by bismuth-based adsorbent suspended above the heated solution. Under optimum conditions, the evaluated assisted digestion methods have been successfully applied, with the exception of pyridine, to several pure organic compounds and two reference materials. COD recoveries obtained with MW and ultrasound-assisted digestion for five real wastewater samples were ranged between 86-97% and 68-91%, respectively, of the values obtained with the classical method (open reflux) used as reference, with relative standard deviation lower than 4% in most cases. Thus, the Mn(III) microwave-assisted digestion method seems to be an interesting and promising alternative to conventional COD digestion methods since it is faster and more environmentally friendly than the ones used for the same purpose.

  9. Source Allocation of Long-Range Asian Dusts Transportation across the Taiwan Strait by Innovative Chemical-Assisted Identification Methods

    Directory of Open Access Journals (Sweden)

    Yi-Hsiu Jen

    2014-01-01

    Full Text Available This study used the backward trajectory calculation to obtain the transportation routes of Asian dusts and further combined the chemical composition with the enrichment factor (EF and the grey relational analysis (GR to identify the potential sources of eighteen Asian dust storm (ADS events. The results showed that the chemical compositions of atmospheric particles sampled at the Pescadores Islands were very similar to source soils fugitively emitted from Inner Mongolia, which could assist in identifying the source regions of Asian dusts. This study further compared the source allocation of Asian dusts obtained from EF, GR, and backward trajectory, which showed that the source regions of Asian dusts obtained from these three methods were quite similar. The similarity of backward trajectory and GR reached as high as 83.3%. Moreover, the similarity of backward trajectory calculation and EF or GR was up to 77.8% while that of the GR and EF was up to 83.3%. Overall, these three methods can successfully allocate the source regions of Asian dusts by 66.7%. Moreover, these innovative chemical-assisted methods can be successfully applied to identify the source regions of Asian dusts for 18 ADS events.

  10. Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Fa-Kuei Tung

    2009-01-01

    Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

  11. Highly efficient and reliable chemically assisted enucleation method for handmade cloning in cattle

    DEFF Research Database (Denmark)

    Vajta, Gábor; Maddox-Hyttel, Poul; Skou, Christina T.

    2005-01-01

    The purpose of the present study was to find an efficient and reliable assisted procedure for enucleation related to the handmade cloning (HMC) technique. After in vitro maturation oocytes were incubated in 0.5 µgmL-¹ demecolcine for 2 h. Subsequently, zonae pellucidae were digested with pronase...

  12. A solar assisted polygeneration system integrating methane reforming and chemical looping combustion with zero carbon emission

    National Research Council Canada - National Science Library

    WANG, Jiangjiang; FU, Chao

    2017-01-01

    .... This paper combines chemical-looping combustion (CLC) and methane reforming with CO2 to accomplish CO2 capture and utilization and proposes a novel polygeneration system to produce syngas, electricity, chilled water for cooling, and hot water...

  13. Microwave assisted rapid growth of Mg(OH){sub 2} nanosheet networks for ethanol chemical sensor application

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hazmi, Faten [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Umar, Ahmad, E-mail: ahmadumar786@gmail.com [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Dar, G.N. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Ghamdi, A.A.; Al-Sayari, S.A. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Al-Hajry, A. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Kim, S.H. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Tuwirqi, Reem M. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Alnowaiserb, Fowzia [Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer A facile microwave-assisted synthesis and characterizations of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Fabrication of ethanol sensor based on (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M). Black-Right-Pointing-Pointer This research opens a way to utilize Mg(OH){sub 2} nanostructures for chemical sensors applications. - Abstract: This paper reports a facile microwave-assisted synthesis of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks and their utilization for the fabrication of efficient ethanol chemical sensor. The synthesized nanosheets networks were characterized in terms of their morphological, structural and optical properties using various analysis techniques such as field emission scanning electron microscopy (FESEM), X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The detailed morphological and structural investigations reveal that the synthesized (Mg(OH){sub 2}) products are nanosheet networks, grown in high density, and possessing hexagonal crystal structure. The optical band gap of as-synthesized Mg(OH){sub 2} nanosheet networks was examined by UV-Vis absorption spectrum, and found to be 5.76 eV. The synthesized nanosheet networks were used as supporting matrices for the fabrication of I-V technique based efficient ethanol chemical sensor. The fabricated ethanol sensor based on nanosheet networks exhibits good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M), with linearity (R = 0.9925) in short response time (10.0 s). This work demonstrate that the simply synthesized Mg(OH){sub 2} nanosheet networks can effectively be used for the fabrication of efficient ethanol chemical sensors.

  14. Beam-profile monitor using a sodium-vapour

    CERN Multimedia

    1972-01-01

    Beam-profile monitor using a sodium-vapour curtain at 45 degrees to the ISR beam in Ring I (sodium generator is in white cylinder just left of centre). Electrons produced by ionization of the sodium vapour give an image of the beam on a fluorescent screen that is observed by a TV camera (at upper right).

  15. CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

    DEFF Research Database (Denmark)

    2017-01-01

    the substrate, wherein heating includes the transmission of electromagnetic heating radiation from a controllable radiative heat source through the reaction chamber towards the substrate, wherein the radiative heat source is controlled to provide electromagnetic radiation as one or more heating pulses, each...

  16. Hot-filament chemical vapour deposition of diamond onto steel

    NARCIS (Netherlands)

    Buijnsters, Ivan

    2003-01-01

    The main goal of this project was to establish the feasibility of depositing well adhering polycrystalline diamond coatings on steel substrates. It is well known that the growth and adhesion of diamond layers directly onto steels is complicated by the high carbon solubility and the high thermal

  17. Crack-free yttria stabilized zirconia thin films by aerosol assisted chemical vapor deposition: Influence of water and carrier gas

    Energy Technology Data Exchange (ETDEWEB)

    Schlupp, M.V.F., E-mail: Meike.Schlupp@mat.ethz.ch [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Binder, S.; Martynczuk, J.; Prestat, M. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Gauckler, L.J. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2012-11-01

    Yttria stabilized zirconia thin films are deposited on silicon single crystal substrates by aerosol assisted chemical vapor deposition from precursor solutions of zirconium and yttrium 2,4-pentanedionate in ethanol. Continuous films are obtained using pure oxygen, pure nitrogen, or mixtures of both as carrier gas. In the simultaneous presence of water and oxygen, crack formation is observed for films deposited at intermediate substrate temperatures (450 Degree-Sign C), while those deposited at low (300 Degree-Sign C) and high (600 Degree-Sign C) temperatures remain crack-free. Crack-free films can be deposited at 450 Degree-Sign C in a water-free setting, or in the presence of water using pure nitrogen as carrier gas. The addition of water to the precursor solutions also significantly reduces film growth rates. - Highlights: Black-Right-Pointing-Pointer Thin film deposition by aerosol assisted chemical vapor deposition (AA-CVD) Black-Right-Pointing-Pointer Yttria stabilized zirconia (YSZ) thin films deposited between 300 Degree-Sign C and 600 Degree-Sign C Black-Right-Pointing-Pointer Water decreases growth rates and leads to crack formation in AA-CVD of YSZ. Black-Right-Pointing-Pointer Crack-free YSZ thin films deposited using oxygen and/or nitrogen as carrier gas Black-Right-Pointing-Pointer YSZ thin films deposited by AA-CVD show low shrinkage on annealing at 1000 Degree-Sign C.

  18. Synthesis by aerosol assisted chemical vapor deposition and microstructural characterization of PbTiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Cano, J.; Hurtado-Macías, A.; Antúnez-Flores, W.; Fuentes-Cobas, L.; González-Hernández, J.; Amézaga-Madrid, P.; Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx

    2013-03-01

    Thin films of PbTiO{sub 3} were deposited onto (001) silicon single-crystal substrates by aerosol assisted chemical vapor deposition method at different temperatures, using organometallic precursors. With the objective of stabilizing and homogenizing the perovskite phase, the films were annealed at 800 °C, in a Pb-rich atmosphere, for 4 and 6 h. The evolution of compositions and microstructure of the films was characterized before and after annealing, by grazing incidence X-ray diffraction, two-dimensional detection of grazing incidence diffraction with synchrotron radiation, scanning electron microscopy and high resolution transmission electron microscopy. X-ray diffraction results showed that the crystalline structure of optimized PbTiO{sub 3} films corresponded to a tetragonal perovskite-type, with lattice parameters a = 0.387(4) nm and c = 0.406(4) nm. In addition, the inverse pole figure of the fiber texture representation, had a Gaussian (1, 1, 0) component and distribution width Ω = 15°. - Highlights: ► We report the synthesis of homogeneous PbTiO{sub 3} thin films on Si substrates. ► They were synthesized by aerosol assisted chemical vapor deposition method. ► Detailed characterization by X-ray diffraction and electron microscopy was performed. ► Crystalline structure of PbTiO{sub 3} films corresponded to a tetragonal perovskite-type. ► The fiber texture representation had a Gaussian (1, 1, 0) component.

  19. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2012-09-12

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  20. Microwave assisted synthesis of polymer via bioplatform chemical intermediate derived from Jatropha deoiled seed cake

    Directory of Open Access Journals (Sweden)

    B.S. Surendra

    2017-09-01

    Full Text Available We report on a two-step catalytic process, where deoiled seed cake as a feed was rapidly depolymerized and converted to a chemical intermediate under mild conditions, and a polymer compound was subsequently synthesized in the presence of an initiator under microwave irradiation. 5-Hydroxymethylfurfural (5-HMF is a significant chemical intermediate compound synthesized from a deoiled Jatropha seed cake under microwave irradiation in the presence of a heterogeneous acid activated Bentonite catalyst. This compound is suitable for the synthesis of polymers. Our study reveals that the synthesis process is an energy-efficient and cost-effective conversion of the deoiled seed cake into the polymer compound through the bioplatform chemical intermediate. The synthesized material was well characterized, confirming the formation and structures of the prepared catalysts.

  1. A proposal for field-level medical assistance in an international humanitarian response to chemical, biological, radiological or nuclear events.

    Science.gov (United States)

    Malich, Gregor; Coupland, Robin; Donnelly, Steve; Baker, David

    2013-10-01

    A capacity for field-level medical assistance for people exposed to chemical, biological, radiological or nuclear (CBRN) agents or medical support for people potentially exposed to these agents is intrinsically linked to the overall risk management approach adopted by the International Committee of the Red Cross (ICRC) for an international humanitarian response to a CBRN event. This medical assistance articulates: ▸the characteristics of the agent concerned (if known) ▸the need for immediate care particularly for people exposed to agents with high toxicity and short latency ▸the imperative for those responding to be protected from exposure to the same agents. This article proposes two distinct capacities for medical assistance--CBRN field medical care and CBRN first aid--that take the above into account and the realities of a CBRN event including the likelihood that qualified medical staff may not be present with the right equipment. These capacities are equally pertinent whether in support of ICRC staff or for assistance of victims of a CBRN event. Training of those who will undertake CBRN field medical care and CBRN first aid must include: ▸knowledge of CBRN agents, their impact on health and the corresponding toxidromes ▸skills to use appropriate equipment ▸use of appropriate means of self-protection ▸an understanding of the additional complexities brought by the need for and interaction of triage, transfer and decontamination. The development of CBRN field medical care and CBRN first aid continues within the ICRC while acknowledging that the opportunities for learning in real situations are extremely limited. Comments from others who work in this domain are welcome.

  2. Graphene composites containing chemically bonded metal oxides

    Indian Academy of Sciences (India)

    Abstract. Composites of graphene involving chemically bonded nano films of metal oxides have been prepared by reacting graphene containing surface oxygen functionalities with metal halide vapours followed by exposure to water vapour. The composites have been characterized by electron microscopy, atomic force ...

  3. US technical assistance to the IAEA and the chemical weapons convection (CWC) - a review and look to the future

    Energy Technology Data Exchange (ETDEWEB)

    Indusi, J.; Parsick, R.J.; Reisman, A.W.

    1997-08-01

    This paper reviews the Safeguards mandate of the International Atomic Energy Agency (IAEA) and describes U.S. technical support programs. We also review the mandate of the Chemical Weapons Convention (CWC) and speculate on the technical areas where U.S. assistance may prove useful. The IAEA was organized in 1957 in response to President Eisenhower`s {open_quotes}Atoms for Peace{close_quotes} initiative presented to the UN General Assembly on December 8, 1953. The Organization for the Prohibition of Chemical Weapons (OPCW) has been organized by a Preparatory Commission (PREPCOM) to prepare for the entry-into-force of this new convention which prohibits the development, production, stockpiling and use of chemical weapons and on their destruction. The safeguards mandate of the IAEA is to carry out verifications of nuclear material pursuant to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and other voluntary but legally binding agreements. U.S. technical support programs have provided and continue to provide assistance in the form of Cost-Free Experts (CFE`s), systems studies on new safeguards approaches, training, computerized information systems, and equipment for nuclear materials measurements and containment and surveillance systems. Because the CWC just recently entered into force (April 29, 1997), verification procedures of the OPCW are not yet fully developed. However, it is expected, and can already be seen for many aspects of the technical task, that there are many similarities between the verification activities of the OPCW and those carried out by the IAEA. This paper will discuss potential technical support areas that can help strengthen the OPCW. 9 refs.

  4. Social support net for chemically dependents: ecomap as instrumental in health assistance

    Directory of Open Access Journals (Sweden)

    Layana de Paula Cavalcante

    2012-06-01

    Full Text Available The social support net is composed by the group of bonds related to the individual. Taking into account that the quality, as well as the quantity of these bonds can interfere in the person's life, acting as positive or negative element, it was identified the need to know this net of relationships by the professionals that takes care of such individuals. It was aimed to assess the Ecomap of drug users assisted in a specialized service as instrumental of support for health care. This is a qualitative research carried out with 19 subjects assisted in a public service, through the Ecomap elaboration. Results show that CAPSad, family and religion constituted strong ties; work, colleagues and friends, links to be strengthened. Neighbors and former fellow drugs users were mentioned as stressors. Ecomap was an evaluation instrument that can be used to help the user to work his bonds, with special reference to those that need to be kept, broken or strengthened as social support.

  5. Effect of MW-assisted roasting on nutritional and chemical properties of hazelnuts

    Directory of Open Access Journals (Sweden)

    Fatih Kalkan

    2015-12-01

    Full Text Available In order to enhance the flavor, texture, color, and appearance of hazelnuts, they are roasted during postharvest processing. In this study, raw hazelnuts (Corylus avellana L. were roasted using microwave (MW and MW-assisted hot air methods under various roasting conditions. The hazelnuts roasted were then examined to determine the percent DPPH radical scavenging activity, antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, total starch, and protein concentration. The roasting experiments were done using a completely randomized factorial arrangement of two roasting types by three roasting times (9, 15, and 21 min by three roasting temperatures (70, 90, and 110°C using three replications within each experiment. These roasting methods were found to yield significant differences in antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, and protein concentration between MW and MW-assisted hot air roasting processes, while no difference was found in percent DPPH radical scavenging activity and total starch. The results obtained may be of great importance to the food research community and industrial hazelnut roasting technologies.

  6. Adaptive Finite Element Method Assisted by Stochastic Simulation of Chemical Systems

    KAUST Repository

    Cotter, Simon L.

    2013-01-01

    Stochastic models of chemical systems are often analyzed by solving the corresponding Fokker-Planck equation, which is a drift-diffusion partial differential equation for the probability distribution function. Efficient numerical solution of the Fokker-Planck equation requires adaptive mesh refinements. In this paper, we present a mesh refinement approach which makes use of a stochastic simulation of the underlying chemical system. By observing the stochastic trajectory for a relatively short amount of time, the areas of the state space with nonnegligible probability density are identified. By refining the finite element mesh in these areas, and coarsening elsewhere, a suitable mesh is constructed and used for the computation of the stationary probability density. Numerical examples demonstrate that the presented method is competitive with existing a posteriori methods. © 2013 Society for Industrial and Applied Mathematics.

  7. Upcycling Waste Lard Oil into Vertical Graphene Sheets by Inductively Coupled Plasma Assisted Chemical Vapor Deposition

    OpenAIRE

    Wu, Angjian; Li, Xiaodong; Yang, Jian; Du, Changming; Shen, Wangjun; Yan, Jianhua

    2017-01-01

    Vertical graphene (VG) sheets were single-step synthesized via inductively coupled plasma (ICP)-enhanced chemical vapor deposition (PECVD) using waste lard oil as a sustainable and economical carbon source. Interweaved few-layer VG sheets, H2, and other hydrocarbon gases were obtained after the decomposition of waste lard oil. The influence of parameters such as temperature, gas proportion, ICP power was investigated to tune the nanostructures of obtained VG, which indicated that a proper tem...

  8. Medical cannabis use in Canada: vapourization and modes of delivery

    Directory of Open Access Journals (Sweden)

    Samantha Shiplo

    2016-10-01

    Full Text Available Abstract Background The mode of medical cannabis delivery—whether cannabis is smoked, vapourized, or consumed orally—may have important implications for its therapeutic efficacy and health risks. However, there is very little evidence on current patterns of use among Canadian medical cannabis users, particularly with respect to modes of delivery. The current study examined modes of medical cannabis delivery following regulatory changes in 2014 governing how Canadians access medical cannabis. Methods A total of 364 approved adult Canadian medical cannabis users completed an online cross-sectional survey between April and June 2015. The survey examined patterns of medical cannabis use, modes of delivery used, and reasons for use. Participants were recruited through a convenience sample from nine Health Canada licensed producers. Results Using a vapourizer was the most popular mode of delivery for medical cannabis (53 %, followed by smoking a joint (47 %. The main reason for using a vapourizer was to reduce negative health consequences associated with smoking. A majority of current vapourizer users reported using a portable vapourizer (67.2 %, followed by a stationary vapourizer (41.7 %, and an e-cigarette or vape pen (19.3 %. Current use of a vapourizer was associated with fewer respiratory symptoms (AOR = 1.28, 95 % CI 1.05–1.56, p = 0.01. Conclusions The findings suggest an increase in the popularity of vapourizers as the primary mode of delivery among approved medical users. Using vapourizers has the potential to prevent some of the adverse respiratory health consequences associated with smoking and may serve as an effective harm reduction method. Monitoring implications of such current and future changes to medical cannabis regulations may be beneficial to policymakers.

  9. Wastewater treatment of chemical laboratory using electro assisted-phytoremediation (EAPR)

    Science.gov (United States)

    Putra, Rudy Syah; Trahadinata, Gilang Ahmad; Latif, Arif; Solehudin, Mochamad

    2017-03-01

    The EAPR process using water hyacinth (Eichornia crassipes) on the wastewater treatment of chemical laboratory had been evaluated. The purpose of the EAPR process was to decrease the BOD, COD and heavy metal concentration in the wastewater. The effectiveness of the process on the wastewater treatment was evaluated using COD, BOD, and heavy metal (Pb, Cu) concentration, respectively. The result showed that the EAPR process decrease the COD, BOD, Pb and Cu in the 4 h of EAPR process. Those concentrations were met the water quality standard of class IV according to government regulation No. 82/2001 regarding the water quality management and water pollution control of the Republic of Indonesia.

  10. Properties of Erbium Doped Hydrogenated Amorphous Carbon Layers Fabricated by Sputtering and Plasma Assisted Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2008-01-01

    Full Text Available We report about properties of carbon layers doped with Er3+ ions fabricated by Plasma Assisted Chemical Vapor Deposition (PACVD and by sputtering on silicon or glass substrates. The structure of the samples was characterized by X-ray diffraction and their composition was determined by Rutherford Backscattering Spectroscopy and Elastic Recoil Detection Analysis. The Absorbance spectrum was taken in the spectral range from 400 nm to 600 nm. Photoluminescence spectra were obtained using two types of Ar laser (λex=514.5 nm, lex=488 nm and also using a semiconductor laser (λex=980 nm. Samples fabricated by magnetron sputtering exhibited typical emission at 1530 nm when pumped at 514.5 nm. 

  11. Synthesis of nanostructured and microstructured ZnO and Zn(OH)2 on activated carbon cloth by hydrothermal and microwave-assisted chemical bath deposition methods

    Science.gov (United States)

    Mosayebi, Elham; Azizian, Saeid; Hajian, Ali

    2015-05-01

    Nanostructured and microstructured ZnO and Zn(OH)2 loaded on activated carbon cloth were synthesized by microwave-assisted chemical bath deposition and hydrothermal methods. By hydrothermal method the deposited sample on carbon fiber is pure ZnO with dandelion-like nanostructures. By microwave-assisted chemical bath method the structure and composition of deposited sample depends on solution pH. At pH = 9.8 the deposited sample on carbon fiber is pure ZnO with flower-like microstructure; but at pH = 10.8 the sample is a mixture of ZnO and Zn(OH)2 with flower-like and rhombic microstructures, respectively. The mechanism of crystal grow by microwave-assisted chemical bath method was investigated by SEM method at both pH.

  12. Use of hydrogen peroxide vapour & plasma irradiation in combination for quick decontamination of closed chambers.

    Science.gov (United States)

    Mourya, Devendra T; Shahani, Hamish C; Yadav, Pragya D; Barde, Pradip V

    2016-08-01

    Various conventional methods such as gaseous, vapour and misting systems, fogging, manual spray and wipe techniques employing a number of chemical agents are used for decontamination of enclosed spaces. Among all these methods, use of aerosolized formaldehyde is the most preferred method due to cost-effectiveness and practical aspects. However, being extremely corrosive in nature generating very irritating fumes and difficulty in maintaining a high level of gas concentration, many laboratories prefer the vaporization of hydrogen peroxide (H 2 O 2 ) as an alternative. We present here the results of using H 2 O 2 vapour in combination with plasma irradiation for quick decontamination of closed chambers. The present study describes a decontamination method, using plasma irradiation in combination with H 2 O 2 (5%). Effect of plasma irradiation and H 2 O 2 on the viability of bacterial spores (Bacillus subtilis), Chikungunya and Kyasanur Forest Disease viruses was assessed. Data suggest that with the combination of H 2 O 2 vapour and plasma irradiation, within short time (three minutes), decontamination of surfaces and space volume could be achieved. Although it showed damage of spores present on the strips, it did not show any penetration power. The results were encouraging, and this method was found to be efficient for achieving surface sterilization in a short time. This application may be useful in laboratories and industries particularly, those working on clean facility concept following good laboratory and manufacturing practices.

  13. Use of hydrogen peroxide vapour & plasma irradiation in combination for quick decontamination of closed chambers

    Directory of Open Access Journals (Sweden)

    Devendra T Mourya

    2016-01-01

    Full Text Available Background & objectives: Various conventional methods such as gaseous, vapour and misting systems, fogging, manual spray and wipe techniques employing a number of chemical agents are used for decontamination of enclosed spaces. Among all these methods, use of aerosolized formaldehyde is the most preferred method due to cost-effectiveness and practical aspects. However, being extremely corrosive in nature generating very irritating fumes and difficulty in maintaining a high level of gas concentration, many laboratories prefer the vaporization of hydrogen peroxide (H 2 O 2 as an alternative. We present here the results of using H 2 O 2 vapour in combination with plasma irradiation for quick decontamination of closed chambers. Methods: The present study describes a decontamination method, using plasma irradiation in combination with H 2 O 2 (5%. Effect of plasma irradiation and H 2 O 2 on the viability of bacterial spores (Bacillus subtilis, Chikungunya and Kyasanur Forest Disease viruses was assessed. Results: Data suggest that with the combination of H 2 O 2 vapour and plasma irradiation, within short time (three minutes, decontamination of surfaces and space volume could be achieved. Although it showed damage of spores present on the strips, it did not show any penetration power. Interpretation & conclusions: The results were encouraging, and this method was found to be efficient for achieving surface sterilization in a short time. This application may be useful in laboratories and industries particularly, those working on clean facility concept following good laboratory and manufacturing practices.

  14. Conversion of lignin into value-added materials and chemicals via laccase-assisted copolymerization.

    Science.gov (United States)

    Cannatelli, Mark D; Ragauskas, Arthur J

    2016-10-01

    With today's environmental concerns and the diminishing supply of the world's petroleum-based chemicals and materials, much focus has been directed toward alternative sources. Woody biomass presents a promising option due to its sheer abundance, renewability, and biodegradability. Lignin, a highly irregular polyphenolic compound, is one of the major chemical constituents of woody biomass and is the second most abundant biopolymer on Earth, surpassed only by cellulose. The pulp and paper and cellulosic ethanol industries produce lignin on the scale of millions of tons each year as a by-product. Traditionally, lignin has been viewed as a waste material and burned as an inefficient fuel. However, in recent decades, research has focused on more economical ways to convert lignin into value-added commodities, such as biofuels, biomaterials, and biochemicals, thus developing and strengthening the concept of fully integrated biorefineries. Owing to the phenolic structure of lignin, it is possible to enzymatically graft molecules onto its surface using laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) to create exciting novel biomaterials. These environmentally friendly enzymes use oxygen as their only co-substrate and produce water as their sole by-product, and have thus found great industrial application. This mini-review highlights recent advances in the field of laccase-facilitated functionalization of lignin as well as promising future directions for lignin-based polymers.

  15. Filtering of oil vapours. Oelfrei lautet die Parole

    Energy Technology Data Exchange (ETDEWEB)

    Goehringer, P.

    1992-07-20

    Air filters are used for removing oil vapours and protecing the respiratory tract. There are centralized solutions such as cyclones side by side with individually mounted filters with casings. (orig.)

  16. Ar+ and CuBr laser-assisted chemical bleaching of teeth: estimation of whiteness degree

    Science.gov (United States)

    Dimitrov, S.; Todorovska, Roumyana; Gizbrecht, Alexander I.; Raychev, L.; Petrov, Lyubomir P.

    2003-11-01

    In this work the results of adaptation of impartial methods for color determination aimed at developing of techniques for estimation of human teeth whiteness degree, sufficiently handy for common use in clinical practice are presented. For approbation and by the way of illustration of the techniques, standards of teeth colors were used as well as model and naturally discolored human teeth treated by two bleaching chemical compositions activated by three light sources each: Ar+ and CuBr lasers, and a standard halogen photopolymerization lamp. Typical reflection and fluorescence spectra of some samples are presented; the samples colors were estimated by a standard computer processing in RGB and B coordinates. The results of the applied spectral and colorimetric techniques are in a good agreement with those of the standard computer processing of the corresponding digital photographs and complies with the visually estimated degree of the teeth whiteness judged according to the standard reference scale commonly used in the aesthetic dentistry.

  17. Optical properties of ultrathin CIGS films studied by spectroscopic ellipsometry assisted by chemical engineering

    Science.gov (United States)

    Loubat, Anaïs; Eypert, Céline; Mollica, Fabien; Bouttemy, Muriel; Naghavi, Negar; Lincot, Daniel; Etcheberry, Arnaud

    2017-11-01

    CIGS (Cu(In1-x,Gax)Se2) based devices are very efficient for photovoltaic conversion. A non-destructive optical study of CIGS is an important challenge as for evaluation of the material quality, and for device modeling. Spectroscopic Ellipsometry (SE) is well adapted for a quantitative characterization only if the handicaps of the roughness limitation, the oxidized surface, or the compositional gradient are minimized. For this SE study, ungraded and thin CIGS samples are prepared with GGI (x) ratio (=[Ga]/([Ga] + [In])) ranging from 0.15 to 0.60. Thanks to chemical engineering based on acidic bromine solution etching and/or HCl de-oxidation, the SE experiments are performed on flattened surfaces, and also, on as grown de-oxidized samples. Using assumptions based on XPS, AFM and SEM complementary characterizations, we give proof of oxide free flattening surfaces and chemical homogeneity in depth. Using these observations, the SE data are modeled on the basis of a three layer model using an Adachi/Tauc-Lorentz formula for the CIGS dispersion. The optical gap values are determined in good agreement with the x ratio measured by the other characterization techniques. SE is able to well estimate the thickness and roughness variations on each sample. Furthermore, the CIGS optical constant extracted on such reference flat surfaces are then applied to the as grown-de-oxidized surfaces, enabling to describe the SE data obtained on rougher surfaces. A complete consistency of the proposed model is shown as well as the capability of SE to be sensitive to the chemistry of the surface.

  18. Vapour galvanizing (Sherardizing) of copper with zinc

    Energy Technology Data Exchange (ETDEWEB)

    Wortelen, Dietbert; Bracht, Hartmut [Westfaelische Wilhelms-Universitaet Muenster (Germany); Natrup, Frank; Graf, Wolfram [Bodycote Waermebehandlung GmbH, Sprockhoevel (Germany)

    2010-07-01

    Using a vapour galvanizing technique called Sherardizing we investigated the growth kinetics and coefficients of zinc copper phases. For this purpose polished (OFHC)-copper plates and zinc powder have been sealed in quartz ampoules under inert gas atmospheres and annealed at a temperature range between 300 and 410 C. In order to study the coating thickness and the phase composition, cross sections were prepared, which have been analyzed by means of optical microscopy and scanning electron microscopy. We were able to demonstrate that the coating thickness is a function of the parabolic time law and that the formed coatings are composed of two layers referring to the ordered {beta}-CuZn and {gamma}-Cu{sub 5}Zn{sub 8}-phases. To enhance the coating quality, small amounts of ZnCl{sub 2} were added to the zinc powder. It was observed that the coating thickness decreased with increasing ZnCl{sub 2}. Experiments with variable Ar-pressure demonstrated a reduced coating growth with increasing pressures. Further measurements with ZnCl{sub 2} were performed to check whether an electrochemical mechanism is involved in the coating process.

  19. Landmine Detection Technologies to TraceExplosive Vapour Detection Techniques

    OpenAIRE

    J. C. Kapoor; G. K. Kannan

    2007-01-01

    Large quantity of explosive is manufactured worldwide for use in various types of ammunition,arms, and mines, and used in armed conflicts. During manufacturing and usage of the explosiveequipment, some of the explosive residues are released into the environment in the form ofcontaminated effluents, unburnt explosives fumes and vapours. Limited but uncontrolledcontinuous release of trace vapours also takes place when explosive-laden landmines are deployedin the field. One of the major technolo...

  20. Variability of winter-time middle atmospheric water vapour over the Arctic as observed with a ground-based microwave radiometer

    Science.gov (United States)

    Tschanz, Brigitte; Kivi, Rigel; Rüfenacht, Rolf; Kämpfer, Niklaus

    2014-05-01

    Middle atmospheric water vapour has a long chemical lifetime and can therefore be used as a tracer for dynamics. The ground-based microwave radiometer MIAWARA-C is designed for the use on campaigns and measures profiles of water vapour in the upper stratosphere and mesosphere and thus provides valuable data for the investigation of atmospheric processes. It has been operational for five years and has successfully participated in measurement campaigns under various climatic conditions in Germany, Switzerland, California, Finland and on la Réunion. The temporal resolution of the obtained water vapour profiles approximately 2 hours depending on tropospheric conditions. During two campaigns from January to June 2010 and from July 2011 to April 2013 in Sodankylä, Finland, MIAWARA-C monitored time series of polar middle atmospheric water vapour for three winters with three Sudden Stratospheric Warmings (SSW) occurring in early 2010, 2012 and 2013. The obtained time series are used to study the effects of the three SSWs on middle-atmospheric water vapour. During an SSW, humid mid- to low-latitude air is transported towards the polar region resulting in a fast increase in water vapour. The descent of water vapour after the SSW allows the estimation of the descent rate over the polar region as the normal wintertime circulation reforms. Results from the three SSWs are compared. The ground-based water vapour data is combined with sonde data of the Finnish Meteorological Institute and ground-based microwave wind measurements for one winter in order to obtain a more complete picture of the dynamics in the polar winter atmosphere.

  1. Carbon Nanomaterial Polymer Composite ChemFET and Chemoresistors For Vapour Sensing

    Science.gov (United States)

    Covington, James A.; Gardner, Julian W.

    2009-05-01

    Carbon nanotubes (CNTs) have been proposed for a broad spectrum of applications, including chemical sensing. Here we report on an investigation of multi-walled CNTs (MWCNTs) as conductive filler for composite polymer sensing films. Such materials combine conductive fillers with an insulating polymer to produce a chemically sensitive, electrically conducting material. These polymer composites offer several important advantages for chemical sensing, including room temperature operation (hence ultra low power), a broad range of selectivities (due to the wide choice of available polymers), and low manufacturing cost. Our approach is to compare the sensing qualities of these composite films, in resistive and field-effect configurations, with existing carbon black polymer composites. Their responses to propanol and toluene vapour in air show that the carbon black resistive sensors outperform CNT sensors by a factor of four in response magnitude. Thus we conclude that for these vapours and using this sensor fabrication method, carbon black polymer composite films are preferable for chemical sensing than MWCNT polymer composites.

  2. Upcycling Waste Lard Oil into Vertical Graphene Sheets by Inductively Coupled Plasma Assisted Chemical Vapor Deposition.

    Science.gov (United States)

    Wu, Angjian; Li, Xiaodong; Yang, Jian; Du, Changming; Shen, Wangjun; Yan, Jianhua

    2017-10-12

    Vertical graphene (VG) sheets were single-step synthesized via inductively coupled plasma (ICP)-enhanced chemical vapor deposition (PECVD) using waste lard oil as a sustainable and economical carbon source. Interweaved few-layer VG sheets, H₂, and other hydrocarbon gases were obtained after the decomposition of waste lard oil. The influence of parameters such as temperature, gas proportion, ICP power was investigated to tune the nanostructures of obtained VG, which indicated that a proper temperature and H₂ concentration was indispensable for the synthesis of VG sheets. Rich defects of VG were formed with a high I D / I G ratio (1.29), consistent with the dense edges structure observed in electron microscopy. Additionally, the morphologies, crystalline degree, and wettability of nanostructure carbon induced by PECVD and ICP separately were comparatively analyzed. The present work demonstrated the potential of our PECVD recipe to synthesize VG from abundant natural waste oil, which paved the way to upgrade the low-value hydrocarbons into advanced carbon material.

  3. Upcycling Waste Lard Oil into Vertical Graphene Sheets by Inductively Coupled Plasma Assisted Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Angjian Wu

    2017-10-01

    Full Text Available Vertical graphene (VG sheets were single-step synthesized via inductively coupled plasma (ICP-enhanced chemical vapor deposition (PECVD using waste lard oil as a sustainable and economical carbon source. Interweaved few-layer VG sheets, H2, and other hydrocarbon gases were obtained after the decomposition of waste lard oil. The influence of parameters such as temperature, gas proportion, ICP power was investigated to tune the nanostructures of obtained VG, which indicated that a proper temperature and H2 concentration was indispensable for the synthesis of VG sheets. Rich defects of VG were formed with a high I D / I G ratio (1.29, consistent with the dense edges structure observed in electron microscopy. Additionally, the morphologies, crystalline degree, and wettability of nanostructure carbon induced by PECVD and ICP separately were comparatively analyzed. The present work demonstrated the potential of our PECVD recipe to synthesize VG from abundant natural waste oil, which paved the way to upgrade the low-value hydrocarbons into advanced carbon material.

  4. Chemical-Assisted Femtosecond Laser Writing of Lab-in-Fiber Sensors

    Science.gov (United States)

    Haque, Moez

    fringe contrast and peak resolution beyond that available with FPIs and offer a significant theoretical improvement in refractometer sensitivity. The advanced laser processes optimized here may provide a new base for photonics, microfluidics, and optofluidics fabrication in a LIF platform with multiplexed functionality and rapid prototyping capabilities of fully integrable 3D optofluidic systems. The proposed LIF devices define new micro-systems for temperature, strain, pressure, refractive index, and bend strain sensing that may find application in the acoustic, aerospace, automotive, biological, chemical, civil, or medical fields.

  5. Chemical-assisted femtosecond laser writing of lab-in-fibers.

    Science.gov (United States)

    Haque, Moez; Lee, Kenneth K C; Ho, Stephen; Fernandes, Luís A; Herman, Peter R

    2014-10-07

    The lab-on-chip (LOC) platform has presented a powerful opportunity to improve functionalization, parallelization, and miniaturization on planar or multilevel geometries that has not been possible with fiber optic technology. A migration of such LOC devices into the optical fiber platform would therefore open the revolutionary prospect of creating novel lab-in-fiber (LIF) systems on the basis of an efficient optical transport highway for multifunctional sensing. For the LIF, the core optical waveguide inherently offers a facile means to interconnect numerous types of sensing elements along the optical fiber, presenting a radical opportunity for optimizing the packaging and densification of diverse components in convenient geometries beyond that available with conventional LOCs. In this paper, three-dimensional patterning inside the optical fiber by femtosecond laser writing, together with selective chemical etching, is presented as a powerful tool to form refractive index structures such as optical waveguides and gratings as well as to open buried microfluidic channels and optical resonators inside the flexible and robust glass fiber. In this approach, optically smooth surfaces (~12 nm rms) are introduced for the first time inside the fiber cladding that precisely conform to planar nanograting structures when formed by aberration-free focusing with an oil-immersion lens across the cylindrical fiber wall. This process has enabled optofluidic components to be precisely embedded within the fiber to be probed by either the single-mode fiber core waveguide or the laser-formed optical circuits. We establish cladding waveguides, X-couplers, fiber Bragg gratings, microholes, mirrors, optofluidic resonators, and microfluidic reservoirs that define the building blocks for facile interconnection of inline core-waveguide devices with cladding optofluidics. With these components, more advanced, integrated, and multiplexed fiber microsystems are presented demonstrating

  6. Measurements of Isotopic Composition of Vapour on the Antarctic Plateau

    Science.gov (United States)

    Casado, M.; Landais, A.; Masson-Delmotte, V.; Genthon, C.; Prie, F.; Kerstel, E.; Kassi, S.; Arnaud, L.; Steen-Larsen, H. C.; Vignon, E.

    2015-12-01

    The oldest ice core records are obtained on the East Antarctic plateau. The composition in stable isotopes of water (δ18O, δD, δ17O) permits to reconstruct the past climatic conditions over the ice sheet and also at the evaporation source. Paleothermometer accuracy relies on good knowledge of processes affecting the isotopic composition of surface snow in Polar Regions. Both simple models such as Rayleigh distillation and global atmospheric models with isotopes provide good prediction of precipitation isotopic composition in East Antarctica but post deposition processes can alter isotopic composition on site, in particular exchanges with local vapour. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum water vapour - precipitation - surface snow - buried snow. While precipitation and snow sampling are routinely performed in Antarctica, climatic conditions in Concordia, very cold (-55°C in average) and very dry (less than 1000ppmv), impose difficult conditions to measure the water vapour isotopic composition. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces (down to 20ppmv). Here we present the results of a campaign of measurement of isotopic composition in Concordia in 2014/2015. Two infrared spectrometers have been deployed or the first time on top of the East Antarctic Plateau allowing a continuous vapour measurement for a month. Comparison of the results from infrared spectroscopy with cryogenic trapping validates the relevance of the method to measure isotopic composition in dry conditions. Identification of different behaviour of isotopic composition in the water vapour associated to turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction.

  7. Retrieving mesospheric water vapour from observations of volume scattering radiances

    Directory of Open Access Journals (Sweden)

    P. Vergados

    2009-02-01

    Full Text Available This study examines the possibility for a theoretical approach in the estimation of water vapour mixing ratios in the vicinity of polar mesospheric clouds (PMC using satellite observations of Volume Scattering Radiances (VSR obtained at the wavelength of 553 nm. The PMC scattering properties perturb the underlying molecular Rayleigh scattered solar radiance of the background atmosphere. As a result, the presence of PMC leads to an enhancement in the observed VSR at the altitude of the layer; the PMC VSRs are superimposed on the exponentially decreasing with height Rayleigh VSR, of the PMC-free atmosphere. The ratio between the observed and the Rayleigh VSR of the background atmosphere is used to simulate the environment in which the cloud layer is formed. In addition, a microphysical model of ice particle formation is employed to predict the PMC VSRs. The initial water vapour profile is perturbed until the modelled VSRs match the observed, at which point the corresponding temperature and water vapour profiles can be considered as a first approximation of those describing the atmosphere at the time of the observations. The role of temperature and water vapour in the cloud formation is examined by a number of sensitivity tests suggesting that the water vapour plays a dominant role in the cloud formation in agreement with experimental results. The estimated water vapour profiles are compared with independent observations to examine the model capability in the context of this study. The results obtained are in a good agreement at the peak of the PMC layer although the radiance rapidly decreases with height below the peak. This simplified scenario indicates that the technique employed can give a first approximation estimate of the water vapour mixing ratio, giving rise to the VSR observed in the presence of PMC.

  8. Program of technical assistance to the Organization for the Prohibition of Chemical Weapons - lessons learned from the U.S. program of technical assistance to IAEA safeguards. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    The Defense Nuclear Agency is sponsoring a technical study of the requirements of a vehicle to meet the OPCW`s future needs for enhanced chemical weapons verification capabilities. This report provides information about the proven mechanisms by which the U.S. provided both short- and long-term assistance to the IAEA to enhance its verification capabilities. Much of the technical assistance has generic application to international organizations verifying compliance with disarmament treaties or conventions. In addition, some of the equipment developed by the U.S. under the existing arrangements can be applied in the verification of other disarmament treaties or conventions. U.S. technical assistance to IAEA safeguards outside of the IAEA`s regular budget proved to be necessary. The U.S. technical assistance was successful in improving the effectiveness of IAEA safeguards for its most urgent responsibilities and in providing the technical elements for increased IAEA {open_quotes}readiness{close_quotes} for the postponed responsibilities deemed important for U.S. policy objectives. Much of the technical assistance was directed to generic subjects and helped to achieve a system of international verification. It is expected that the capabilities of the Organization for the Prohibition of Chemical Weapons (OPCW) to verify a state`s compliance with the {open_quotes}Chemical Weapons Convention{close_quotes} will require improvements. This report presents 18 important lessons learned from the experience of the IAEA and the U.S. Program of Technical Assistance to IAEA Safeguards (POTAS), organized into three tiers. Each lesson is presented in the report in the context of the difficulty, need and history in which the lesson was learned. Only the most important points are recapitulated in this executive summary.

  9. FAF-Drugs2: Free ADME/tox filtering tool to assist drug discovery and chemical biology projects

    Directory of Open Access Journals (Sweden)

    Miteva Maria A

    2008-09-01

    Full Text Available Abstract Background Drug discovery and chemical biology are exceedingly complex and demanding enterprises. In recent years there are been increasing awareness about the importance of predicting/optimizing the absorption, distribution, metabolism, excretion and toxicity (ADMET properties of small chemical compounds along the search process rather than at the final stages. Fast methods for evaluating ADMET properties of small molecules often involve applying a set of simple empirical rules (educated guesses and as such, compound collections' property profiling can be performed in silico. Clearly, these rules cannot assess the full complexity of the human body but can provide valuable information and assist decision-making. Results This paper presents FAF-Drugs2, a free adaptable tool for ADMET filtering of electronic compound collections. FAF-Drugs2 is a command line utility program (e.g., written in Python based on the open source chemistry toolkit OpenBabel, which performs various physicochemical calculations, identifies key functional groups, some toxic and unstable molecules/functional groups. In addition to filtered collections, FAF-Drugs2 can provide, via Gnuplot, several distribution diagrams of major physicochemical properties of the screened compound libraries. Conclusion We have developed FAF-Drugs2 to facilitate compound collection preparation, prior to (or after experimental screening or virtual screening computations. Users can select to apply various filtering thresholds and add rules as needed for a given project. As it stands, FAF-Drugs2 implements numerous filtering rules (23 physicochemical rules and 204 substructure searching rules that can be easily tuned.

  10. Chemical composition of lipids present in cat and dog oocyte by matrix-assisted desorption ionization mass spectrometry (MALDI- MS).

    Science.gov (United States)

    Apparicio, M; Ferreira, C R; Tata, A; Santos, V G; Alves, A E; Mostachio, G Q; Pires-Butler, E A; Motheo, T F; Padilha, L C; Pilau, E J; Gozzo, F C; Eberlin, M N; Lo Turco, E G; Luvoni, G C; Vicente, W R R

    2012-12-01

    The aim of the present study was to investigate the level of information on the chemical structures and relative abundances of lipids present in cat and dog oocytes by matrix-assisted laser desorption mass spectrometry (MALDI-MS). The MALDI-MS approach requires a simple analysis workflow (no lipid extraction) and few samples (two or three oocytes per analysis in this work) providing concomitant profiles of both intact phospholipids such as sphingomyelins (SM) and phosphatidylcholines (PC) as well as triacylglycerols (TAG). The lipids were detected in oocytes by MALDI using dihydroxybenzoic acid (DHB) as the matrix. The most abundant lipid present in the MS profiles of bitch and queen oocytes was a PC containing 34 carbons and one unsaturation [PC (34:1)]. Oocytes of these two species are characterized by differences in PC and TAG profiles detected qualitatively as well as by means of principal component analysis (PCA). Cat oocytes were mainly discriminated by more intense C52 and C54 TAG species and a higher number of unsaturations, indicating predominantly linoleic and oleic fatty acyl residues. Comparison of the lipid profile of bitch and queen oocytes with that of bovine oocytes revealed some similarities and also some species specificity: TAG species present in bovine oocytes were also present in bitches and queens; however, a more pronounced contribution of palmitic, stearic and oleic fatty acid residues was noticed in the lipid profile of bovine oocytes. MALDI-MS provides novel information on chemical lipid composition in canine and feline oocytes, offering a suitable tool to concomitantly monitor, in a nearly direct and simple fashion the composition of phospholipids and TAG. This detailed information is highly needed to the development of improved protocols for in vitro culture and cryopreservation of cat and dog oocytes. © 2012 Blackwell Verlag GmbH.

  11. Tris(phosphino)borato silver(I) complexes as precursors for metallic silver aerosol-assisted chemical vapor deposition.

    Science.gov (United States)

    McCain, Matthew N; Schneider, Sven; Salata, Michael R; Marks, Tobin J

    2008-04-07

    A series of light- and air-stable tris(phosphino)borato silver(I) complexes has been synthesized, structurally and spectroscopically characterized, and implemented in the growth of low resistivity metallic silver thin films by aerosol-assisted chemical vapor deposition (AACVD). Of the four complexes in the series, [RB(CH2PR'2) 3]AgPEt3 (R = Ph (1, 3), (n)Bu (2, 4); R' = Ph (1, 2), (i)Pr (3, 4), complexes 1 and 2 have been characterized by single-crystal X-ray diffraction. Complex 2 represents a significant improvement over previously available nonfluorinated Ag precursors, owing to ease of handling and efficient film deposition characteristics. Thermogravimetric analysis (TGA) shows that the thermolytic properties of these complexes can be significantly modified by altering the ligand structure. Polycrystalline cubic-phase Ag thin films were grown on glass, MgO(100), and 52100 steel substrates. Ag films of thicknesses 3 microm, grown at rates of 14-18 nm/min, exhibit low levels of extraneous element contamination by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that film growth proceeds primarily via an island growth (Volmer-Weber) mechanism.

  12. Antibacterial properties and chemical characterization of the essential oils from summer savory extracted by microwave-assisted hydrodistillation

    Science.gov (United States)

    Rezvanpanah, Shila; Rezaei, Karamatollah; Golmakani, Mohammad-Taghi; Razavi, Seyyed Hadi

    2011-01-01

    Antibacterial properties and chemical characterization of the essential oils from summer savory (Satureja hortensis) extracted by microwave-assisted hydrodistillation (MAHD) were compared with those of the essential oils extracted using the traditional hydrodistillation (HD) method. While MAHD at 660 W required half as much time as HD needed, similar antibacterial efficacies were found from the essential oils obtained by the two extraction methods on two food pathogens (Staphylococcus aureus, a gram positive bacterium, and Escherchia coli, a gram negative bacterium). Also, as it was the case with the essential oils extracted by HD, that of MAHD indicated greater influence on S. aureus than on E. coli. The compositions of the extracted essential oils were also studied using GC-MS analysis. The same components with negligible differences in their quantities were found in the extracted essential oils using the two methods outlined above. Overall, to reduce the extraction time, MAHD can be applied at higher microwave levels without any compromise in the antibacterial properties of the essential oils extracted. PMID:24031778

  13. Improved ERO modelling for spectroscopy of physically and chemically assisted eroded beryllium from the JET-ILW

    Directory of Open Access Journals (Sweden)

    D. Borodin

    2016-12-01

    Full Text Available Physical and chemical assisted physical sputtering were characterised by the BeI and BeII line and BeD band emission in the observation chord measuring the sightline integrated emission in front of the inner beryllium limiter at the torus midplane. The 3D local transport and plasma-surface interaction Monte-Carlo modelling (ERO code [18] is a key for the interpretation of the observations in the vicinity of the shaped solid Be limiter. The plasma parameter variation (density scan in limiter regime has provided a useful material for the simulation benchmark. The improved background plasma parameters input, the new analytical expression for particle tracking in the sheath region and implementation of the BeD release into ERO has helped to clarify some deviations between modelling and experiments encountered in the previous studies [4,5]. Reproducing the observations provides additional confidence in our ‘ERO-min’ fit for the physical sputtering yields for the plasma-wetted areas based on simulated data.

  14. Dual-functional aniline-assisted wet-chemical synthesis of bismuth telluride nanoplatelets and their thermoelectric performance

    Science.gov (United States)

    Li, Changcun; Kong, Fangfang; Liu, Congcong; Liu, Huixuan; Hu, Yongjing; Wang, Tongzhou; Xu, Jingkun; Jiang, Fengxing

    2017-06-01

    The wet-chemical approach is of great significance for the synthesis of two-dimensional (2D) bismuth telluride nanoplatelets as a potential thermoelectric (TE) material. Herein, we proposed a simple and effective solution method with the assistance of aniline for the fabrication of bismuth telluride nanoplatelets at a low temperature of 100 °C. The choice of aniline with its dual function avoided the simultaneous use of a capping regent and a toxic reductant. The as-synthesized nanoplatelets have a large size of more than 900 × 500 nm2 and a small thickness of 15.4 nm. The growth of bismuth telluride nanoplatelets are related to the Bi/Te ratio of precursors indicating that a larger content of the Bi precursor is more conducive to the formation of 2D nanoplatelets. The bismuth telluride nanoplatelets pressed into a pellet show a smaller electrical resistivity (˜6.5 × 10-3 Ω · m) and a larger Seebeck coefficient (-135 μV K-1), as well as a lower thermal conductivity (0.27 W m-1 K-1) than those of nanoparticles. The next goal is to further reduce the electrical resistivity and optimize the TE performance by disposing of the residual reactant of aniline adsorbed on the surface of the nanoplatelets.

  15. Iron selenide films by aerosol assisted chemical vapor deposition from single source organometallic precursor in the presence of surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Raja Azadar [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Badshah, Amin, E-mail: aminbadshah@yahoo.com [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Younis, Adnan [School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia); Khan, Malik Dilshad [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Akhtar, Javeed [Department of Physics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad (Pakistan)

    2014-09-30

    This article presents the synthesis and characterization (multinuclear nuclear magnetic resonance, Fourier transform infrared spectroscopy, carbon–hydrogen–nitrogen–sulfur analyzer, atomic absorption spectrometry and thermogravimetric analysis) of a single source organometallic precursor namely 1-acetyl-3-(4-ferrocenylphenyl)selenourea for the fabrication of iron selenide (FeSe) films on glass substrates using aerosol assisted chemical vapor deposition (AACVD). The changes in the morphologies of the films have been monitored by the use of two different surfactants i.e. triton X-100 and tetraoctylphosphonium bromide during AACVD. The role of surfactant has been evaluated by examining the interaction of the surfactants with the precursor by using UV–vis spectroscopy and cyclic voltammetry. The fabricated FeSe films have been characterized with powder X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. - Highlights: • Ferrocene incorporated selenourea (FIS) has been synthesized and characterized. • FeSe thin films have been fabricated from FIS. • Mechanism of film growth was studied with cyclic voltammetry and UV–vis spectroscopy.

  16. The wettability between etching solutions and the surface of multicrystalline silicon wafer during metal-assisted chemical etching process

    Science.gov (United States)

    Niu, Y. C.; Liu, Z.; Liu, X. J.; Gao, Y.; Lin, W. L.; Liu, H. T.; Jiang, Y. S.; Ren, X. K.

    2017-01-01

    In order to investigate the wettability of multicrystalline silicon (mc-Si) with the etching solutions during metal-assisted chemical etching process, different surface structures were fabricated on the p-type multi-wire slurry sawn mc-Si wafers, such as as-cut wafers, polished wafers, and wafers etched in different solutions. The contact angles of different etching solutions on the surfaces of the wafers were measured. It was noted that all contact angles of etching solutions were smaller than the corresponding ones of deionized water, but the contact angles of different etching solutions were quite different. Among the contact angles of the etching solutions of AgNO3-HF, H2O2-HF, TMAH and HNO3-HF, the contact angle of TMAH solution was much larger than the others and that of HNO3-HF solution was much smaller. It is suggested that the larger contact angle may lead to an unevenly etching of silicon wafer due to the long retention of big bubbles on the wafers in the etching reaction, which should be paid attention to and overcome.

  17. Minimizing Isolate Catalyst Motion in Metal-Assisted Chemical Etching for Deep Trenching of Silicon Nanohole Array.

    Science.gov (United States)

    Kong, Lingyu; Zhao, Yunshan; Dasgupta, Binayak; Ren, Yi; Hippalgaonkar, Kedar; Li, Xiuling; Chim, Wai Kin; Chiam, Sing Yang

    2017-06-21

    The instability of isolate catalysts during metal-assisted chemical etching is a major hindrance to achieve high aspect ratio structures in the vertical and directional etching of silicon (Si). In this work, we discussed and showed how isolate catalyst motion can be influenced and controlled by the semiconductor doping type and the oxidant concentration ratio. We propose that the triggering event in deviating isolate catalyst motion is brought about by unequal etch rates across the isolate catalyst. This triggering event is indirectly affected by the oxidant concentration ratio through the etching rates. While the triggering events are stochastic, the doping concentration of silicon offers a good control in minimizing isolate catalyst motion. The doping concentration affects the porosity at the etching front, and this directly affects the van der Waals (vdWs) forces between the metal catalyst and Si during etching. A reduction in the vdWs forces resulted in a lower bending torque that can prevent the straying of the isolate catalyst from its directional etching, in the event of unequal etch rates. The key understandings in isolate catalyst motion derived from this work allowed us to demonstrate the fabrication of large area and uniformly ordered sub-500 nm nanoholes array with an unprecedented high aspect ratio of ∼12.

  18. Nanopore-type black silicon anti-reflection layers fabricated by a one-step silver-assisted chemical etching.

    Science.gov (United States)

    Lu, Yen-Tien; Barron, Andrew R

    2013-06-28

    An effective and economical fabrication process for the synthesis of nanopore-type "black silicon", that significantly decreases reflectivity of silicon wafer surfaces, is reported using a room temperature one-step Ag-assisted chemical etching method. The effects on the surface morphology and the corresponding surface reflectivity of the concentration of the silver catalyst (500, 50, and 5 μM), the HF and H2O2 concentration in the silicon etchant, the HF : H2O2 ratio, and etching time have been investigated. Lower reflectivity is a balance between sufficient silver catalyst to create large numbers of nanopores on a silicon surface and excessive silver that brings deeply etched channels that would potentially short-circuit a solar cell junction. The lowest relative effective reflectivity (0.17% over a range of 300-1000 nm) occurs with a silver ion concentration of 50 μM, however, with the silver ion concentration decreases to 5 μM surfaces with a low relative effective reflectivity (2.60%) and a short nanopore length (one-pot), low cost (low silver concentration), energy efficient (room temperature), method for the synthesis of anti-reflection layers for silicon-based solar cell applications.

  19. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  20. Can painted glass felt or glass fibre cloth be used as vapour barrier?

    DEFF Research Database (Denmark)

    El-Khattam, Amira; Andersen, Mie Them; Hansen, Kurt Kielsgaard

    2014-01-01

    with a ventilated attic where the ceiling may be air tight but has no vapour barrier; post-insulation of the attic may cause the need for a vapour barrier. Placing a vapour barrier above the ceiling can be tiresome and it is difficult to ensure tightness. A simpler way is to paint a vapour barrier directly...... on the ceiling e.g. as an ordinary paint. This paper presents the results of an investigation of the water vapour resistance of surface treatments which are commonly used in-door. The water vapour resistance was measured by the cup method. Aerated concrete was investigated with and without various surface...

  1. Stabilisation of Collagen Sponges by Glutaraldehyde Vapour Crosslinking

    Directory of Open Access Journals (Sweden)

    Yong Y. Peng

    2017-01-01

    Full Text Available Glutaraldehyde is a well-recognised reagent for crosslinking and stabilising collagens and other protein-based materials, including gelatine. In some cases, however, the use of solutions can disrupt the structure of the material, for example, by causing rapid dispersion or distortions from surface interactions. An alternative approach that has been explored in a number of individual cases is the use of glutaraldehyde vapour. In this study, the effectiveness of a range of different glutaraldehyde concentrations in the reservoir providing vapour, from 5% to 25% (w/v, has been explored at incubation times from 5 h to 48 h at room temperature. These data show the effectiveness of the glutaraldehyde vapour approach for crosslinking collagen and show that materials with defined, intermediate stability could be obtained, for example, to control resorption rates in vivo.

  2. The ignitability of petrol vapours and potential for vapour phase explosion by use of TASER® law enforcement electronic control device.

    Science.gov (United States)

    Clarke, C; Andrews, S P

    2014-12-01

    An experimental study was made of the potential of the TASER-X26™ law enforcement electronic control device to ignite petrol vapours if used by an officer to incapacitate a person soaked in petrol, or within a flammable atmosphere containing petrol vapour. Bench scale tests have shown that a wooden mannequin with pig skin covering the chest was a suitable representation of a human target. Full scale tests using the mannequin have shown that the arc from a TASER-X26™ is capable of igniting petrol/air vapours on a petrol-soaked person. Further tests in a 1/5 scale and a full scale compartment have shown that if a TASER is used within a compartment, a petrol vapour explosion (deflagration) may be achieved. It is evident from this research that if used in a flammable vapour rich environment, the device could prove fatal not only to the target but the TASER® operator as well. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Intercomparison of TCCON and MUSICA Water Vapour Products

    Science.gov (United States)

    Weaver, D.; Strong, K.; Deutscher, N. M.; Schneider, M.; Blumenstock, T.; Robinson, J.; Notholt, J.; Sherlock, V.; Griffith, D. W. T.; Barthlott, S.; García, O. E.; Smale, D.; Palm, M.; Jones, N. B.; Hase, F.; Kivi, R.; Ramos, Y. G.; Yoshimura, K.; Sepúlveda, E.; Gómez-Peláez, Á. J.; Gisi, M.; Kohlhepp, R.; Warneke, T.; Dohe, S.; Wiegele, A.; Christner, E.; Lejeune, B.; Demoulin, P.

    2014-12-01

    We present an intercomparison between the water vapour products from the Total Carbon Column Observing Network (TCCON) and the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA), two datasets from ground-based Fourier Transform InfraRed (FTIR) spectrometers with good global representation. Where possible, comparisons to radiosondes are also included. The near-infrared TCCON measurements are optimized to provide precise monitoring of greenhouse gases for carbon cycle studies; however, TCCON's retrievals also produce water vapour products. The mid-infrared MUSICA products result from retrievals optimized to give precise and accurate information about H2O, HDO, and δD. The MUSICA water vapour products have been validated by extensive intercomparisons with H2O and δD in-situ measurements made from ground, radiosonde, and aircraft (Schneider et al. 2012, 2014), as well as by intercomparisons with satellite-based H2O and δD remote sensing measurements (Wiegele et al., 2014). This dataset provides a valuable reference point for other measurements of water vapour. This study is motivated by the limited intercomparisons performed for TCCON water vapour products and limited characterisation of their uncertainties. We compare MUSICA and TCCON products to assess the potential for TCCON measurements to contribute to studies of the water cycle, water vapour's role in climate and use as a tracer for atmospheric dynamics, and to evaluate the performance of climate models. The TCCON and MUSICA products result from measurements taken using the same FTIR instruments, enabling a comparison with constant instrumentation. The retrieval techniques differ, however, in their method and a priori information. We assess the impact of these differences and characterize the comparability of the TCCON and MUSICA datasets.

  4. Efficient quantification of water content in edible oils by headspace gas chromatography with vapour phase calibration.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-11-24

    An automated and accurate headspace gas chromatographic (HS-GC) technique was investigated for rapidly quantifying water content in edible oils. In this method, multiple headspace extraction (MHE) procedures were used to analyse the integrated water content from the edible oil sample. A simple vapour phase calibration technique with an external vapour standard was used to calibrate both the water content in the gas phase and the total weight of water in edible oil sample. After that the water in edible oils can be quantified. The data showed that the relative standard deviation of the present HS-GC method in the precision test was less than 1.13%, the relative differences between the new method and a reference method (i.e. the oven-drying method) were no more than 1.62%. The present HS-GC method is automated, accurate, efficient, and can be a reliable tool for quantifying water content in edible oil related products and research. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  5. Metal-assisted chemical etching in HF/Na2S2O8 OR HF/KMnO4 produces porous silicon

    NARCIS (Netherlands)

    Hadjersi, T.; Gabouze, N.; Kooij, Ernst S.; Zinine, A.; Zinine, A.; Ababou, A.; Chergui, W.; Cheraga, H.; Belhousse, S.; Djeghri, A.

    2004-01-01

    A new metal-assisted chemical etching method using Na2S2O8 or KMnO4 as an oxidizing agent was proposed to form a porous silicon layer on a highly resistive p-type silicon. A thin layer of Ag or Pd is deposited on the Si(100) surface prior to immersion in a solution of HF and Na2S2O8 or HF and KMnO4.

  6. Human volunteer study with PGME: Eye irritation during vapour exposure

    NARCIS (Netherlands)

    Emmen, H.H.; Muijser, H.; Arts, J.H.E.; Prinsen, M.K.

    2003-01-01

    The objective of this study was to establish the possible occurrence of eye irritation and subjective symptoms in human volunteers exposed to propylene glycol monomethyl ether (PGME) vapour at concentrations of 0, 100 and 150 ppm. Testing was conducted in 12 healthy male volunteers using a repeated

  7. Making ET AAS Determination Less Dependent on Vapourization ...

    African Journals Online (AJOL)

    The general solution of the problem comes from the integration of running absorbance normalized with regard to vapour transportation velocity. ... those introduced together with excessive amounts of Mg and Pd. The methodology suggested reduced the error associated with change of atomization kinetics from 20 to 2 %.

  8. Analysis of radiosonde data on tropospheric water vapour in Nigeria ...

    African Journals Online (AJOL)

    The analyses of some atmospheric water vapour parameters derived from radiosonde data at the three existing radiosonde stations in Nigeria are reported. The stations essentially represent the climates of the southern (coastal), middlebelt (savannah), and northern (sub-sahel) regions of the country. Monthly means of the ...

  9. Making ET AAS Determination Less Dependent on Vapourization ...

    African Journals Online (AJOL)

    NICO

    bGerman Aerospace Center, PT-SW, 12489 Berlin, Germany. Received 4 December 2012, revised 5 May 2013, accepted 7 May 2013. ABSTRACT. The quantification of the analytes in ET AAS is normally attained by the measurement and integration of transient absorbance. High degree of atomization and constant vapour ...

  10. Vapour intrusion from the vadose zone—seven algorithms compared

    NARCIS (Netherlands)

    Provoost, J.; Bosman, A.; Reijnders, L.; Bronders, J.; Touchant, K.; Swartjes, F.

    2010-01-01

    Background, aim and scope: Vapours of volatile organic compounds (VOCs) emanating from contaminated soils may move through the unsaturated zone to the subsurface. VOC in the subsurface can be transported to the indoor air by convective air movement through openings in the foundation and basement.

  11. Upper tropospheric water vapour variability over tropical latitudes ...

    Indian Academy of Sciences (India)

    Upper tropospheric water vapour variability over tropical latitudes observed using radiosonde and satellite measurements. Ghouse Basha1, M Venkat Ratnam1,∗ and B V Krishna Murthy2. 1National Atmospheric Research Laboratory (NARL), Department of Space, Government of India,. Gadanki, PB No. 123, Tirupati 517 ...

  12. Carbon dioxide and water vapour characteristics on the west coast ...

    Indian Academy of Sciences (India)

    Carbon dioxide and water vapour in the atmo- sphere are considered as the green-house gases and responsible for the global warming, hence much attention has been given to its measurement and analysis (Jones et al. 1978; Jones and Smith 1977;. Leuning et al. 1982; Ohtaki and Matsui 1982;. Ohtaki 1985).

  13. Erratum to: Measurement of copper vapour laser-induced ...

    Indian Academy of Sciences (India)

    Erratum to: Measurement of copper vapour laser-induced deformation of dielectric-coated mirror surface by. Michelson interferometer. A WAHID. ∗. , S KUNDU, J S B SINGH, A K SINGH, A KHATTAR,. S K MAURYA, J S DHUMAL and K DASGUPTA. Laser & Plasma Technology Division, Beam Technology Development ...

  14. Distillation with Vapour Compression. An Undergraduate Experimental Facility.

    Science.gov (United States)

    Pritchard, Colin

    1986-01-01

    Discusses the need to design distillation columns that are more energy efficient. Describes a "design and build" project completed by two college students aimed at demonstrating the principles of vapour compression distillation in a more energy efficient way. General design specifications are given, along with suggestions for teaching…

  15. Detection of explosive vapour using surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Fang, X.; Ahmad, S. R.

    2009-11-01

    A commercially available nano-structured gold substrate was used for activating surface-enhanced Raman scattering (SERS). Raman spectra of the vapour of explosive material, triacetonetriperoxide (TATP), at trace concentrations produced from adsorbed molecules on such surfaces have been studied. Prominent Raman lines of the explosive molecular species were recorded at a sample temperature of ˜35°C, which is near to human body temperature. For this study, the concentration of the adsorbed TATP molecules on the nano-structured surface was varied by heating the sample to different temperatures and exposing the substrate to the sample vapour for different lengths of time. The intensities of the Raman lines have been found to increase with the increase in temperature and also with the increase in the duration of exposure for a fixed temperature. However, as expected, the Raman intensities have been found to saturate at higher temperatures and longer exposures. These saturation effects of the strengths of the Raman lines in the SERS of TATP vapour have been investigated in this paper. The results indicate that the optimisation for vapour deposition on the surface could be a crucial factor for any quantitative estimate of the concentration of the molecular species adsorbed on the nano-structured substrates.

  16. Variation In Surface Water Vapour Density Over Four Nigerian Stations

    African Journals Online (AJOL)

    The surface water vapour density ρ has been studied using monthly averages of temperature and relative humidity at four selected weather stations in Nigeria for the years 1987 to 1991. It is found that during the dry season months of November to March, ρ is higher at night by an average of about 9.9% than during the day ...

  17. Antifungal Activity of Clove Essential Oil and its Volatile Vapour Against Dermatophytic Fungi

    OpenAIRE

    Chee, Hee Youn; Lee, Min Hee

    2007-01-01

    Antifungal activities of clove essential oil and its volatile vapour against dermatophytic fungi including Candida albicans, Epidermophyton floccosum. Microsporum audouinii, Trichophyton mentagrophytes, and Trichophyton rubrum were investigated. Both clove essential oil and its volatile vapour strongly inhibit spore germination and mycelial growth of the dermatophytic fungi tested. The volatile vapour of clove essential oil showed fungistatic activity whereas direct application of clove essen...

  18. Performance evaluation of a solar ejector-vapour compression cycle for cooling application

    Science.gov (United States)

    Megdouli, K.; Elakhdar, M.; Nahdi, E.; Kairouani, L.; Mhimid, A.

    2015-04-01

    This study deals with the performance of the ejector-vapour compression cycle assisted by solar. The effect of operating conditions on the combined cycle performance is examined. Also, a comparison of the system performance with environment friendly refrigerants (R134a, R600, R123, R141b, R142b, R152a, R290, and R245fa) is made. This performance is calculated using an empirical correlation. Thermodynamic properties of functioning fluids are obtained with package REFPROP 8. Using the typical meteorological year file containing the weather data of the city of Tunis, the system performance is computed for three collector types. The theoretical results show that the R290 offers the highest coefficient of performance, COP=3.75, for generator temperature TB = 78°C, condenser temperature Tc = 30°C and the intercooler temperature Te = 15°C.

  19. Damage-Free Smooth-Sidewall InGaAs Nanopillar Array by Metal-Assisted Chemical Etching.

    Science.gov (United States)

    Kong, Lingyu; Song, Yi; Kim, Jeong Dong; Yu, Lan; Wasserman, Daniel; Chim, Wai Kin; Chiam, Sing Yang; Li, Xiuling

    2017-10-24

    Producing densely packed high aspect ratio In0.53Ga0.47As nanostructures without surface damage is critical for beyond Si-CMOS nanoelectronic and optoelectronic devices. However, conventional dry etching methods are known to produce irreversible damage to III-V compound semiconductors because of the inherent high-energy ion-driven process. In this work, we demonstrate the realization of ordered, uniform, array-based In0.53Ga0.47As pillars with diameters as small as 200 nm using the damage-free metal-assisted chemical etching (MacEtch) technology combined with the post-MacEtch digital etching smoothing. The etching mechanism of InxGa1-xAs is explored through the characterization of pillar morphology and porosity as a function of etching condition and indium composition. The etching behavior of In0.53Ga0.47As, in contrast to higher bandgap semiconductors (e.g., Si or GaAs), can be interpreted by a Schottky barrier height model that dictates the etching mechanism constantly in the mass transport limited regime because of the low barrier height. A broader impact of this work relates to the complete elimination of surface roughness or porosity related defects, which can be prevalent byproducts of MacEtch, by post-MacEtch digital etching. Side-by-side comparison of the midgap interface state density and flat-band capacitance hysteresis of both the unprocessed planar and MacEtched pillar In0.53Ga0.47As metal-oxide-semiconductor capacitors further confirms that the surface of the resultant pillars is as smooth and defect-free as before etching. MacEtch combined with digital etching offers a simple, room-temperature, and low-cost method for the formation of high-quality In0.53Ga0.47As nanostructures that will potentially enable large-volume production of In0.53Ga0.47As-based devices including three-dimensional transistors and high-efficiency infrared photodetectors.

  20. Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites.

    Science.gov (United States)

    Kierys, Agnieszka; Krasucka, Patrycja; Grochowicz, Marta

    2017-11-01

    The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

  1. Multivariate prediction of eight kerosene properties employing vapour-phase mid-infrared spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    M.P. Gomez-Carracedo; J.M. Andrade; M. Calvino; E. Fernandez; D. Prada; S. Muniategui [University of La Coruna, La Coruna (Spain)

    2003-07-01

    Eight physico-chemical properties of kerosene (aviation jet fuel) are predicted employing vapour-phase generation, Fourier transform mid-infrared (FT-MIR) spectra and partial least squares regression (PLS). Two devices were implemented and studied in order to generate the kerosene vapour from 100 liquid samples from a Spanish refinery. One of them is very simple whilst the other one requires thermostatic and gas flow controls. The FT-MIR spectra are recorded and used to deploy PLS models for each property (distillation curve, flash point, freezing point, percentage of aromatics and viscosity) and each device. In general, the simplest device yields the more satisfactory models. Several criteria are used to evaluate their performance: the average prediction error (corrected to take into account the error in the reference values), the F-test to assess the absence of bias in the predictions, repeatability and reproducibility. In general, all the models provide unbiased predictions, with low average errors and good precision. 31 refs., 7 figs., 2 tabs.

  2. a-SiCxNy thin films deposited by a microwave plasma assisted CVD process using a CH4/N2/Ar/HMDSN mixture: Methane rate effect

    Science.gov (United States)

    Bulou, S.; Le Brizoual, L.; Miska, P.; de Poucques, L.; Hugon, R.; Belmahi, M.

    2010-06-01

    Amorphous silicon carbonitride thin films were deposited using a microwave plasma assisted chemical vapour deposition process fed with a mixture of methane, nitrogen, argon and hexamethyldisilazane (Si2C6H19N). Effects of the methane rate on thin films composition, nanostructuration and characteristics are investigated by means of various techniques such as X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy, Transmission Electron Microscopy and UV-Visible absorption. The raise of the methane rate results in less organic, denser films and in an increase of refractive index.

  3. Performance Improvement of Microcrystalline p-SiC/i-Si/n-Si Thin Film Solar Cells by Using Laser-Assisted Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The microcrystalline p-SiC/i-Si/n-Si thin film solar cells treated with hydrogen plasma were fabricated at low temperature using a CO2 laser-assisted plasma enhanced chemical vapor deposition (LAPECVD system. According to the micro-Raman results, the i-Si films shifted from 482 cm−1 to 512 cm−1 as the assisting laser power increased from 0 W to 80 W, which indicated a gradual transformation from amorphous to crystalline Si. From X-ray diffraction (XRD results, the microcrystalline i-Si films with (111, (220, and (311 diffraction were obtained. Compared with the Si-based thin film solar cells deposited without laser assistance, the short-circuit current density and the power conversion efficiency of the solar cells with assisting laser power of 80 W were improved from 14.38 mA/cm2 to 18.16 mA/cm2 and from 6.89% to 8.58%, respectively.

  4. Copper-vapor-assisted chemical vapor deposition for high-quality and metal-free single-layer graphene on amorphous SiO2 substrate.

    Science.gov (United States)

    Kim, Hyungki; Song, Intek; Park, Chibeom; Son, Minhyeok; Hong, Misun; Kim, Youngwook; Kim, Jun Sung; Shin, Hyun-Joon; Baik, Jaeyoon; Choi, Hee Cheul

    2013-08-27

    We report that high-quality single-layer graphene (SLG) has been successfully synthesized directly on various dielectric substrates including amorphous SiO2/Si by a Cu-vapor-assisted chemical vapor deposition (CVD) process. The Cu vapors produced by the sublimation of Cu foil that is suspended above target substrates without physical contact catalyze the pyrolysis of methane gas and assist nucleation of graphene on the substrates. Raman spectra and mapping images reveal that the graphene formed on a SiO2/Si substrate is almost defect-free and homogeneous single layer. The overall quality of graphene grown by Cu-vapor-assisted CVD is comparable to that of the graphene grown by regular metal-catalyzed CVD on a Cu foil. While Cu vapor induces the nucleation and growth of SLG on an amorphous substrate, the resulting SLG is confirmed to be Cu-free by synchrotron X-ray photoelectron spectroscopy. The SLG grown by Cu-vapor-assisted CVD is fabricated into field effect transistor devices without transfer steps that are generally required when SLG is grown by regular CVD process on metal catalyst substrates. This method has overcome two important hurdles previously present when the catalyst-free CVD process is used for the growth of SLG on fused quartz and hexagonal boron nitride substrates, that is, high degree of structural defects and limited size of resulting graphene, respectively.

  5. Rotatory power of sodium vapour oriented by laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bicchi, P. (Siena Univ. (Italy). Ist. di Fisica); Moi, L.; Zambon, B. (Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisica Atomica e Moleculare)

    1979-01-11

    In this paper the rotatory power of sodium vapour is studied when laser light is used as pumping as well as analysis light. The possibility of having an analysis light whose frequency may be varied in a range larger than the interval between the D/sub 1/ and D/sub 2/ atomic lines allows us to get for the first time the complete shape of the rotation curve and to measure a rotation different from zero even for frequencies very far from the resonance ones. The complete orientation in the vapour caused by the laser pumping-light power permits to obtain very high rotation values. In a cell containing Na and 200 Torr of Ne, we measured, at 185/sup 0/C, 10/sup 0//cm of specific rotation. The dependence of the optical activity on the buffer gas pressure and on the frequency of the pumping light is also studied.

  6. Air sampling and determination of vapours and aerosols of bitumen and polycyclic aromatic hydrocarbons in the Human Bitumen Study.

    Science.gov (United States)

    Breuer, Dietmar; Hahn, Jens-Uwe; Höber, Dieter; Emmel, Christoph; Musanke, Uwe; Rühl, Reinhold; Spickenheuer, Anne; Raulf-Heimsoth, Monika; Bramer, Rainer; Seidel, Albrecht; Schilling, Bernd; Heinze, Evelyn; Kendzia, Benjamin; Marczynski, Boleslaw; Welge, Peter; Angerer, Jürgen; Brüning, Thomas; Pesch, Beate

    2011-06-01

    The chemical complexity of emissions from bitumen applications is a challenge in the assessment of exposure. Personal sampling of vapours and aerosols of bitumen was organized in 320 bitumen-exposed workers and 69 non-exposed construction workers during 2001-2008. Area sampling was conducted at 44 construction sites. Area and personal sampling of vapours and aerosols of bitumen showed similar concentrations between 5 and 10 mg/m(3), while area sampling yielded higher concentrations above the former occupational exposure limit (OEL) of 10 mg/m(3). The median concentration of personal bitumen exposure was 3.46 mg/m(3) (inter-quartile range 1.80-5.90 mg/m(3)). Only few workers were exposed above the former OEL. The specificity of the method measuring C-H stretch vibration is limited. This accounts for a median background level of 0.20 mg/m³ in non-exposed workers which is likely due to ubiquitous aliphatic hydrocarbons. Further, area measurements of polycyclic aromatic hydrocarbons (PAHs) were taken at 25 construction sites. U.S. EPA PAHs were determined with GC/MS, with the result of a median concentration of 2.47 μg/m(3) at 15 mastic asphalt worksites associated with vapours and aerosols of bitumen, with a Spearman correlation coefficient of 0.45 (95% CI -0.13 to 0.78). PAH exposure at mastic-asphalt works was higher than at reference worksites (median 0.21 μg/m(3)), but about one order of magnitude lower compared to coke-oven works. For a comparison of concentrations of vapours and aerosols of bitumen and PAHs in asphalt works, differences in sampling and analytical methods must to be taken into account.

  7. Atmospheric radio refractivity and water vapour density at Oshodi ...

    African Journals Online (AJOL)

    ... columnar water vapour density ρ can be used to estimate N over Oshodi, and Kano. For instance, line of regression of N upon ρ for Oshodi at the 0-3km atmospheric column is N = (4.93 ± 0.75) ρ + 254.15 ± 11.26. Keywords: atmospheric humidity, columnar radio refractivity. Nigeria Journal of Pure and Applied Physics Vol ...

  8. Functionalization of Hydrogenated Chemical Vapour Deposition-Grown Graphene by On-Surface Chemical Reactions

    Czech Academy of Sciences Publication Activity Database

    Drogowska, Karolina; Kovaříček, Petr; Kalbáč, Martin

    2017-01-01

    Roč. 23, č. 17 (2017), s. 4073-4078 ISSN 0947-6539 R&D Projects: GA MŠk LL1301; GA MŠk(CZ) LM2015073 Grant - others:AVČR PPPLZ(CZ) L200401551 Institutional support: RVO:61388955 Keywords : functionalization * graphene * hydrogen ation * Raman spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 5.317, year: 2016

  9. a-SiC{sub x}N{sub y} thin films deposited by a microwave plasma assisted CVD process using a CH{sub 4}/N{sub 2}/Ar/HMDSN mixture: Methane rate effect

    Energy Technology Data Exchange (ETDEWEB)

    Bulou, S; Miska, P; Poucques, L de; Hugon, R; Belmahi, M [Institut Jean Lamour (IJL) CNRS UMR 7198, Nancy (France); Brizoual, L Le, E-mail: simon.bulou@uhp-nancy.fr [Institut Jean Rouxel (IMN) CNRS UMR 6502, Nantes (France)

    2010-06-15

    Amorphous silicon carbonitride thin films were deposited using a microwave plasma assisted chemical vapour deposition process fed with a mixture of methane, nitrogen, argon and hexamethyldisilazane (Si{sub 2}C{sub 6}H{sub 19}N). Effects of the methane rate on thin films composition, nanostructuration and characteristics are investigated by means of various techniques such as X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy, Transmission Electron Microscopy and UV-Visible absorption. The raise of the methane rate results in less organic, denser films and in an increase of refractive index.

  10. Formation of a-Si:H and a-Si{sub 1-x}C{sub x} :H nanowires by Ag-assisted electroless etching in aqueous HF/AgNO{sub 3} solution

    Energy Technology Data Exchange (ETDEWEB)

    Douani, Rachida [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Piret, Gaelle, E-mail: gaelle.offranc@polytechnique.edu [Physique de la Matiere Condensee, Ecole Polytechnique, CNRS, 91128 Palaiseau (France); Hadjersi, Toufik [Unite de Developpement de la Technologie du Silicium (UDTS), 2, Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Algiers (Algeria); Chazalviel, Jean-Noel; Solomon, Ionel [Physique de la Matiere Condensee, Ecole Polytechnique, CNRS, 91128 Palaiseau (France)

    2011-06-01

    The formation of hydrogenated amorphous silicon-carbon alloy (a-Si{sub 1-x}C{sub x}:H) nanowires is studied for different carbon concentrations (0-7%) by using Ag-assisted electroless etching of the thin a-Si{sub 1-x}C{sub x}:H films deposited by plasma-enhanced chemical vapour deposition from silane/methane gas mixtures. The nanowires morphologies (length, density, ...), studied by scanning electron microscopy, strongly depend on the concentration of the etchant (aqueous solution of hydrofluoric acid and silver nitrate), the etching time, and the carbon concentration of the deposited layer.

  11. Improvement of ultrastructural preservation of Eimeria oocysts by microwave-assisted chemical fixation or by high pressure freezing and freeze substitution.

    Science.gov (United States)

    Kurth, Thomas; Wiedmer, Stefanie; Entzeroth, Rolf

    2012-03-01

    Fixation and preparation for electron microscopy of coccidian oocysts is a general problem. Especially in sporulated oocysts, proper fixation and resin infiltration are hindered by the robust oocyst wall. Conventional chemical fixation therefore leads to artefacts that obscure cellular details in the oocysts. In this study, sporulated oocysts of Eimeria nieschulzi were subjected to different fixation and embedding protocols: conventional chemical fixation and embedding in Spurr's resin, microwave-assisted fixation and processing followed by embedding in epon, and high pressure freezing followed by freeze substitution and epon embedding. The samples were finally studied by transmission electron microscopy. Many ultrastructural features of the oocyst wall and the sporozoites were already substantially improved after microwaved-assisted fixation and processing. However, the fine structural preservation still suffered from shrinkage and artificial extraction, which occured during dehydration and infiltration. High pressure freezing (HPF) and freeze substitution (FS) revealed much better preservation. Oocyst walls retained their ovoid shape, and the ultrastructure of sporozoites was well preserved with no signs of shrinkage or extraction. HPF and FS are therefore a suitable method for the ultrastructural analysis of coccidian oocysts. Copyright © 2011 Elsevier GmbH. All rights reserved.

  12. Factors affecting release of ethanol vapour in active modified atmosphere packaging systems for horticultural products

    Directory of Open Access Journals (Sweden)

    Weerawate Utto

    2014-04-01

    Full Text Available The active modified atmosphere packaging (active MAP system , which provides interactive postharvest control , using ethanol vapour controlled release, is one of the current interests in the development of active packaging for horticultural products. A number of published research work have discussed the relationship between the effectiveness of ethanol vapour and its concentration in the package headspace, including its effect on postharvest decay and physiological controls. This is of importance because a controlled release system should release and maintain ethanol vapour at effective concentrations during the desired storage period. A balance among the mass transfer processes of ethanol vapour in the package results in ethanol vapour accumulation in the package headspace. Key factors affecting these processes include ethanol loading, packaging material, packaged product and storage environment (temperature and relative h umidity. This article reviews their influences and discusses future work required to better understand their influences on ethanol vapour release and accumulations in active MAP.

  13. A Study of a QCM Sensor Based on TiO2 Nanostructures for the Detection of NO2 and Explosives Vapours in Air

    Directory of Open Access Journals (Sweden)

    Marcin Procek

    2015-04-01

    Full Text Available The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM containing a TiO2 nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO2 concentrations in an atmosphere of synthetic air have been described. The constructed NO2 sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied.

  14. A Study of a QCM Sensor Based on TiO2 Nanostructures for the Detection of NO2 and Explosives Vapours in Air

    Science.gov (United States)

    Procek, Marcin; Stolarczyk, Agnieszka; Pustelny, Tadeusz; Maciak, Erwin

    2015-01-01

    The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM) containing a TiO2 nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO2 concentrations in an atmosphere of synthetic air have been described. The constructed NO2 sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied. PMID:25912352

  15. Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

    Science.gov (United States)

    Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

    2017-08-01

    Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the

  16. Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS through laboratory studies of inorganic species

    Directory of Open Access Journals (Sweden)

    W. Hu

    2017-08-01

    Full Text Available Aerosol mass spectrometers (AMSs and Aerosol Chemical Speciation Monitors (ACSMs commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE to correct for the loss of particles due to bounce. A new capture vapourizer (CV has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH42SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ∼ 200–800 °C on the detected fragments, CE and size distributions are investigated. A Tv of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity for more volatile species (e.g. NH4NO3 and comparable to or higher than the SV for less-volatile species (e.g. (NH42SO4, demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very

  17. Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data

    Directory of Open Access Journals (Sweden)

    H. Herbin

    2007-07-01

    Full Text Available The isotopologic composition of water vapour in the atmosphere provides valuable information on many climate, chemical and dynamical processes. The accurate measurements of the water isotopologues by remote-sensing techniques remains a challenge, due to the large spatial and temporal variations. Simultaneous profile retrievals of the main water isotopologues (i.e. H216O, H218O and HDO and their ratios are presented here for the first time, along their retrieved global distributions. The results are obtained by exploiting the high resolution infrared spectra recorded by the Interferometric Monitor for Greenhouse gases (IMG instrument, which has operated in the nadir geometry onboard the ADEOS satellite between 1996 and 1997. The retrievals are performed on cloud-free radiances, measured during ten days of April 1997, considering two atmospheric windows (1205–1228 cm−1; 2004–2032 cm−1 and using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM. Characterizations in terms of vertical sensitivity and error budget are provided. We show that a relatively high vertical resolution is achieved for H216O (~4–5 km, and that the retrieved profiles are in fair agreement with local sonde measurements, at different latitudes. The retrieved global distributions of H216O, H218O, HDO and their ratios are presented and found to be consistent with previous experimental studies and models. The Ocean-Continent difference, the latitudinal and vertical dependence of the water vapour amount and the isotopologic depletion are notably well reproduced. Others trends, possibly related to small-scale variations in the vertical profiles are also discussed. Despite the difficulties encountered for computing accurately the isotopologic ratios, our results demonstrate the ability

  18. The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

    Science.gov (United States)

    Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

    2014-01-01

    We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

  19. High growth rate homoepitaxial diamond film deposition at high temperatures by microwave plasma-assisted chemical vapor deposition

    Science.gov (United States)

    Vohra, Yogesh K. (Inventor); McCauley, Thomas S. (Inventor)

    1997-01-01

    The deposition of high quality diamond films at high linear growth rates and substrate temperatures for microwave-plasma chemical vapor deposition is disclosed. The linear growth rate achieved for this process is generally greater than 50 .mu.m/hr for high quality films, as compared to rates of less than 5 .mu.m/hr generally reported for MPCVD processes.

  20. Water vapour loss threshold and induction of cholinergic urticaria.

    Science.gov (United States)

    Tupker, R A; Doeglas, H M

    1990-01-01

    A patient is described with cholinergic urticaria (CU) in whom the symptoms could be provoked by gustatory stimuli. The aim of this study was to investigate whether there is a threshold of sweating (monitored by skin water vapour loss (SVL) measurements) at which CU can be provoked. Provocations with lemon and sal-ammoniac liquorice induced transient sweating differing both in degree and duration. Only 'doubly salted' liquorice, which caused the most intense sweat response, resulted in urticarial lesions. This findings suggest a threshold dependency for the induction of CU. SVL measurement may be a useful method for the evaluation of sweating tests in CU patients.

  1. Combustion dynamics of low vapour pressure nanofuel droplets

    Science.gov (United States)

    Pandey, Khushboo; Chattopadhyay, Kamanio; Basu, Saptarshi

    2017-07-01

    Multiscale combustion dynamics, shape oscillations, secondary atomization, and precipitate formation have been elucidated for low vapour pressure nanofuel [n-dodecane seeded with alumina nanoparticles (NPs)] droplets. Dilute nanoparticle loading rates (0.1%-1%) have been considered. Contrary to our previous studies of ethanol-water blend (high vapour pressure fuel), pure dodecane droplets do not exhibit internal boiling after ignition. However, variation in surface tension due to temperature causes shape deformations for pure dodecane droplets. In the case of nanofuels, intense heat release from the enveloping flame leads to the formation of micron-size aggregates (of alumina NPS) which serve as nucleation sites promoting heterogeneous boiling. Three boiling regimes (A, B, and C) have been identified with varying bubble dynamics. We have deciphered key mechanisms responsible for the growth, transport, and rupture of the bubbles. Bubble rupture causes ejections of liquid droplets termed as secondary atomization. Ejection of small bubbles (mode 1) resembles the classical vapour bubble collapse mechanism near a flat free surface. However, large bubbles induce severe shape deformations as well as bulk oscillations. Rupture of large bubbles results in high speed liquid jet formation which undergoes Rayleigh-Plateau tip break-up. Both modes contribute towards direct fuel transfer from the droplet surface to flame envelope bypassing diffusion limitations. Combustion lifetime of nanofuel droplets consequently has two stages: stage I (where bubble dynamics are dominant) and stage II (formation of gelatinous mass due to continuous fuel depletion; NP agglomeration). In the present work, variation of flame dynamics and spatio-temporal heat release (HR) have been analysed using high speed OH* chemiluminescence imaging. Fluctuations in droplet shape and flame heat release are found to be well correlated. Droplet flame is bifurcated in two zones (I and II). Flame response is

  2. Essential Oils Extracted Using Microwave-Assisted Hydrodistillation from Aerial Parts of Eleven Artemisia Species: Chemical Compositions and Diversities in Different Geographical Regions of Iran

    Directory of Open Access Journals (Sweden)

    Majid Mohammadhosseini

    2017-03-01

    Full Text Available This study aimed to assess the chemical compositions of essential oils (EOs extracted through microwave-assisted hydrodistillation from aerial parts of 11 Artemisia species growing wild in different regions in Northern, Eastern, Western, and Central parts of Iran. The EOs were subsequently analyzed via GC and GC-MS. The percentage yields of the EOs varied over the range of 0.21-0.50 (w/w%. On the basis of these characterizations and spectral assignments, natural compounds including camphor, 1,8-cineole, camphene, α-pinene, β-pinene, β-thujone, and sabinene were the most abundant and frequent constituents among all studied chemical profiles. Accordingly, oxygenated monoterpenes, monoterpene hydrocarbons, and non-terpene hydrocarbons were the dominant groups of natural compounds in the chemical profiles of 13, 4, and 2 samples, respectively. Moreover, five chemotypes were identified using statistical analyses: camphene, α-pinene and β-pinene; 1,8-cineole; camphore and 1,8-cineole; camphore and camphore and β-thujone.

  3. Formaldehyde assisted reduction achieved p-type orthorhombic tin oxide film prepared by an inexpensive chemical method

    Science.gov (United States)

    Sun, Jian; Chen, Zequn; Nie, Sha; Yu, Zhigen; Yan, Shenghui; Gong, Hao; Tang, Chunhua; Bai, Xue; Xu, Jianmei; Zhao, Ling; Zhou, Wei; Wang, Qing

    2017-11-01

    The fabrication of tin oxide thin film of orthorhombic phase has been succeeded under the high pressures from 1.5 GPa to 50 GPa. In this paper, we demonstrate the viability of p-type tin oxide thin film at atmosphere pressure of 0.1 MPa, by a chemical method employing formaldehyde (HCHO) during the annealing process. By using formaldehyde to form formaldehyde-argon mixed reducing ambiance in the chemical sol-gel process, limited oxidation is reached and p-type tin oxide films of orthorhombic phase under ambient pressure are eventually achieved under optimized experimental conditions. Specifically, we have developed a p-type tin oxide thin film with an optimal Hall mobility of 8.6 cm2 V‑1 s‑1. Besides, our results reveal that a Sn rich environment can lead to a higher hole mobility experimentally.

  4. A miniature discriminating monitor for tritiated water vapour

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, R.A.H.; Ravazzani, A.; Pacenti, P. [European Commission, JRC, Institute for Advanced Material, Ispra, Vatican City State, Holy See (Italy); Campi, F. [Nuclear Engineering Dept., Polytechnic of Milan (Italy)

    1998-07-01

    In detecting tritium in air (or other gas) for worker safety, it is important to discriminate between tritiated water vapour and elemental tritium, because the first is much more easily absorbed in the lungs. We haveinvented (patent pending) an innovative discriminating monitor which works better than existing designs, and is much smaller. The air (or other sample gas) passes over a large surface area of solid scintillator, which is surface-treated to make it hygroscopic. Tritiated water vapour in the air exchanges continuously, rapidly and reversibly with the water in the thin hygroscopic layer; which is of the order of 1 micron thick. The beta-emissions from tritium in the hygroscopic layer hit the solid scintillator, causing flashes of light that are detected by a photomultiplier. The new discriminating monitor for tritiated species in air offers superior performance to existing discriminating monitors, and is much smaller. It is planned to develop a portable version which could serve as a personal tritium monitor. (authors)

  5. Droplet spectrum at different vapour pressure deficits1

    Directory of Open Access Journals (Sweden)

    Christiam Felipe Silva Maciel

    Full Text Available ABSTRACT An efficient pesticides spraying depends a lot in psychrometric conditions, mainly if it is using fine droplets, once climatic conditions may cause droplets evaporation and consequent financial loss to the farmer. Thus, the aim of this work was to determine the droplet spectrum depending on the vapour pressure deficits. The work was carried out inside of a climate chamber to obtain the vapour pressure deficits (VPDair. The laser particle analyzer, model Spraytech, was used to determine the droplet spectrum, and the experiment was conducted in factorial scheme 5 x 20, consisted of five working pressures (100; 200; 300; 400 and 500 kPa and twenty VPDair (2.3; 3.2; 4.2; 5.6; 7.0; 7.4; 9.5; 11.7; 12.7; 15.8; 16.4; 16.9; 21.2; 22.1; 22.2; 28.1; 29.7; 36.9 39.4 e 51.6 hPa, in completely randomized design with five replications. There is influence of VPDair on droplet spectrum behavior. Increasing the VPDair reduces the percentage of sprayed volume comprised by droplets with diameter between 100 and 200 µm, between 200 and 300 µm, between 300 and 400 µm, between 400 and 500 µm and between 500 and 600 µm. Increasing VPDair increases the VMD, Dv90, SPAN and the percentage of sprayed volume comprised by droplets larger than 600 µm.

  6. Study of water vapour adsorption kinetics on aluminium oxide materials

    Science.gov (United States)

    Livanova, Alesya; Meshcheryakov, Evgeniy; Reshetnikov, Sergey; Kurzina, Irina

    2017-11-01

    Adsorbents on the basis of active aluminum oxide are still of demand on the adsorbent-driers market. Despite comprehensive research of alumina adsorbents, and currently is an urgent task to improve their various characteristics, and especially the task of increasing the sorption capacity. In the present work kinetics of the processes of water vapours' adsorption at room temperature on the surface of desiccant samples has been studied. It was obtained on the basis of bayerite and pseudoboehmite experimentally. The samples of pseudoboehmite modified with sodium and potassium ions were taken as study objects. The influence of an adsorbent's grain size on the kinetics of water vapours' adsorption was studied. The 0.125-0.25 mm and 0.5-1.0 mm fractions of this sample were used. It has been revealed that the saturation water vapor fine powder (0.125-0.25 mm) is almost twofold faster in comparison with the sample of fraction 0.5-1.0 mm due to the decrease in diffusion resistance in the pores of the samples when moving from the sample of larger fraction to the fine-dispersed sample. It has been established that the adsorption capacity of the pseudoboehmite samples, modified by alkaline ions, is higher by ˜40 %, than for the original samples on the basis of bayerite and pseudoboehmite.

  7. Thermally decarboxylated sodium bicarbonate: Interactions with water vapour, calorimetric study

    Directory of Open Access Journals (Sweden)

    Natalia Volkova

    2013-06-01

    Full Text Available Isothermal titration calorimetry (ITC was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate (NaHCO3. The decarboxylation degree of the samples was varied from 3% to 35% and the humidity range was 54–100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% (RHo, was determined as the inflection point on a plot of the mean−ΔHkJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake (m was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheider’s salt on the bicarbonate surface is proposed for humidities below RHo. Keywords: Isothermal titration calorimetry, Sodium bicarbonate, Sodium carbonate, Trona salt, Wegscheider’s salt, Enthalpy, Relative humidity, Pyrolytic decarboxylation

  8. Sub-10-nm patterning via directed self-assembly of block copolymer films with a vapour-phase deposited topcoat.

    Science.gov (United States)

    Suh, Hyo Seon; Kim, Do Han; Moni, Priya; Xiong, Shisheng; Ocola, Leonidas E; Zaluzec, Nestor J; Gleason, Karen K; Nealey, Paul F

    2017-07-01

    Directed self-assembly (DSA) of the domain structure in block copolymer (BCP) thin films is a promising approach for sub-10-nm surface patterning. DSA requires the control of interfacial properties on both interfaces of a BCP film to induce the formation of domains that traverse the entire film with a perpendicular orientation. Here we show a methodology to control the interfacial properties of BCP films that uses a polymer topcoat deposited by initiated chemical vapour deposition (iCVD). The iCVD topcoat forms a crosslinked network that grafts to and immobilizes BCP chains to create an interface that is equally attractive to both blocks of the underlying copolymer. The topcoat, in conjunction with a chemically patterned substrate, directs the assembly of the grating structures in BCP films with a half-pitch dimension of 9.3 nm. As the iCVD topcoat can be as thin as 7 nm, it is amenable to pattern transfer without removal. The ease of vapour-phase deposition, applicability to high-resolution BCP systems and integration with pattern-transfer schemes are attractive properties of iCVD topcoats for industrial applications.

  9. Sub-10-nm patterning via directed self-assembly of block copolymer films with a vapour-phase deposited topcoat

    Science.gov (United States)

    Suh, Hyo Seon; Kim, Do Han; Moni, Priya; Xiong, Shisheng; Ocola, Leonidas E.; Zaluzec, Nestor J.; Gleason, Karen K.; Nealey, Paul F.

    2017-07-01

    Directed self-assembly (DSA) of the domain structure in block copolymer (BCP) thin films is a promising approach for sub-10-nm surface patterning. DSA requires the control of interfacial properties on both interfaces of a BCP film to induce the formation of domains that traverse the entire film with a perpendicular orientation. Here we show a methodology to control the interfacial properties of BCP films that uses a polymer topcoat deposited by initiated chemical vapour deposition (iCVD). The iCVD topcoat forms a crosslinked network that grafts to and immobilizes BCP chains to create an interface that is equally attractive to both blocks of the underlying copolymer. The topcoat, in conjunction with a chemically patterned substrate, directs the assembly of the grating structures in BCP films with a half-pitch dimension of 9.3 nm. As the iCVD topcoat can be as thin as 7 nm, it is amenable to pattern transfer without removal. The ease of vapour-phase deposition, applicability to high-resolution BCP systems and integration with pattern-transfer schemes are attractive properties of iCVD topcoats for industrial applications.

  10. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    Energy Technology Data Exchange (ETDEWEB)

    Razavizadeh, Mahmoud; Jamshidi, Masoud, E-mail: mjamshidi@iust.ac.ir

    2016-08-30

    Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  11. Chemical analysis of pharmaceuticals and explosives in fingermarks using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry.

    Science.gov (United States)

    Kaplan-Sandquist, Kimberly; LeBeau, Marc A; Miller, Mark L

    2014-02-01

    Chemical analysis of latent fingermarks, "touch chemistry," has the potential of providing intelligence or forensically relevant information. Matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF MS) was used as an analytical platform for obtaining mass spectra and chemical images of target drugs and explosives in fingermark residues following conventional fingerprint development methods and MALDI matrix processing. There were two main purposes of this research: (1) develop effective laboratory methods for detecting drugs and explosives in fingermark residues and (2) determine the feasibility of detecting drugs and explosives after casual contact with pills, powders, and residues. Further, synthetic latent print reference pads were evaluated as mimics of natural fingermark residue to determine if the pads could be used for method development and quality control. The results suggest that artificial amino acid and sebaceous oil residue pads are not suitable to adequately simulate natural fingermark chemistry for MALDI/TOF MS analysis. However, the pads were useful for designing experiments and setting instrumental parameters. Based on the natural fingermark residue experiments, handling whole or broken pills did not transfer sufficient quantities of drugs to allow for definitive detection. Transferring drugs or explosives in the form of powders and residues was successful for preparing analytes for detection after contact with fingers and deposition of fingermark residue. One downfall to handling powders was that the analyte particles were easily spread beyond the original fingermark during development. Analyte particles were confined in the original fingermark when using transfer residues. The MALDI/TOF MS was able to detect procaine, pseudoephedrine, TNT, and RDX from contact residue under laboratory conditions with the integration of conventional fingerprint development methods and MALDI matrix. MALDI/TOF MS is a nondestructive

  12. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal

    2015-12-22

    The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  13. Structural and photoluminescent properties of nanowires formed by the metal-assisted chemical etching of monocrystalline silicon with different doping level

    Energy Technology Data Exchange (ETDEWEB)

    Georgobiani, V. A., E-mail: v.georgobiani@gmail.com; Gonchar, K. A.; Osminkina, L. A.; Timoshenko, V. Yu. [Lomonosov Moscow State University, Faculty of Physics (Russian Federation)

    2015-08-15

    Silicon-nanowire layers grown by the metal-assisted chemical etching of (100)-oriented p-type monocrystalline silicon substrates with a resistivity of 10 and 0.001 Ω · cm are studied by electron microscopy, Raman scattering, and photoluminescence measurements. It is established that nanowires grown on lightly doped substrates are structurally nonporous and formed as crystalline cores covered by nanocrystals 3–5 nm in dimensions. Nanowires grown on heavily doped substrates are structurally porous and contain both small nanocrystals and coarser crystallites with equilibrium charge carriers that influence interband radiative recombination. It is found that the photoluminescence intensity of nanowires in the spectral range 1.3–2.0 eV depends on the presence of molecular oxygen.

  14. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications.

    Science.gov (United States)

    Alias, Mohd S; Yang, Yang; Ng, Tien K; Dursun, Ibrahim; Shi, Dong; Saidaminov, Makhsud I; Priante, Davide; Bakr, Osman M; Ooi, Boon S

    2016-01-07

    The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  15. Epitaxial ZnO Thin Films on a-Plane Sapphire Substrates Grown by Ultrasonic Spray-Assisted Mist Chemical Vapor Deposition

    Science.gov (United States)

    Nishinaka, Hiroyuki; Kamada, Yudai; Kameyama, Naoki; Fujita, Shizuo

    2009-12-01

    High-quality epitaxial ZnO thin films were grown by an ultrasonic spray-assisted mist chemical vapor deposition (CVD) on a-plane sapphire substrates with ZnO buffer layers. The ZnO thin films were grown with c-axis orientation without notable rotational domains. Surface morphologies and electrical properties were markedly improved as an effect of the ZnO buffer layers. The mobility in the ZnO epitaxial (main) layer was estimated to be 90 cm2/(V·s), which is reasonably high compared with those in ZnO layers grown by CVD processes. Photoluminescence at a low temperature (4.5 K) revealed a free A-exiton peak, and that at room temperature showed a strong band-edge peak with little deep-level luminescence.

  16. Growth of shape- and size-selective zinc oxide nanorods by a microwave-assisted chemical bath deposition method: effect on photocatalysis properties.

    Science.gov (United States)

    Shinde, Vaishali R; Gujar, Tanaji P; Noda, Takeshi; Fujita, Daisuke; Vinu, Ajayan; Grandcolas, Mathieu; Ye, Jinhua

    2010-09-10

    Herein, we demonstrate the shape- and size-selective growth of ZnO nanostructures on indium tin oxide-coated glass substrates by using a microwave-assisted chemical bath deposition method. By systematically controlling the deposition parameters, it is possible to produce shape- and size-selective nanostructures with high alignment and uniformity. Specifically, the pH of the bath can be used to control the shape of rods from bundled structures to tapered and flat tips. Furthermore, the deposition temperature can be used to control the size of the ZnO array from 770 to 125 nm. The prepared rods were active catalysts in the degradation of methylene blue under UV radiation, and exhibited size-dependent activity.

  17. Synthesis of Bifunctional Fe3O4@SiO2-Ag Magnetic-Plasmonic Nanoparticles by an Ultrasound Assisted Chemical Method

    Science.gov (United States)

    Chu, Dung Tien; Sai, Doanh Cong; Luu, Quynh Manh; Tran, Hong Thi; Quach, Truong Duy; Kim, Dong Hyun; Nguyen, Nam Hoang

    2017-06-01

    Bifunctional magnetic-plasmonic nanoparticles (NPs)—Fe3O4@SiO2-Ag were successfully synthesized by an ultrasound assisted chemical method. Silver ions were absorbed and then reduced by sodium borohydride on the surface of 3-aminopropyltriethoxysilane (APTES) functionalized silica-coated magnetic NPs, then they were reduced under the influence of a 200 W ultrasonic wave for 60 min. When the amount of precursor silver ions increased, the relative intensity of diffraction peaks of silver crystals in all samples increased with the atomic ratio of silver/iron increasing from 0.208 to 0.455 and saturation magnetization ( M s) decreasing from 44.68 emu/g to 34.74 emu/g. The NPs have superparamagnetic properties and strong surface plasmon absorption at 420 nm, which make these particles promising for biomedical applications.

  18. Vapour phase corrosion inhibitors from South African renewable resources and their evaluation

    CSIR Research Space (South Africa)

    Vuorinen, E

    2006-02-01

    Full Text Available A vapour-phase corrosion inhibitor (VCI) needs to be a volatile compound or a mixture of compounds. It reaches the surfaces that need to be protected from corrosion via the vapour phase and forms a relatively stable bond at the interface...

  19. Utility of DMSP-SSM/I for integrated water vapour over the Indian seas

    Indian Academy of Sciences (India)

    Recent algorithms for Special Sensor Microwave/Imager (DMSP-SSM/I) satellite data are used for estimating integrated water vapour over the Indian seas. ... On the basis of this algorithm, distribution of integrated water vapour is determined during the monsoon depression (22nd{27th July, 1992) that formed over the Bay of ...

  20. Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination

    DEFF Research Database (Denmark)

    Fumagalli, F; Kylian, O; Amato, Letizia

    2012-01-01

    Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can...... vapour plasma process are discussed for practical applications in medical devices decontamination....

  1. Ethanol vapour sensing properties of screen printed WO3 thick films

    Indian Academy of Sciences (India)

    This paper presents ethanol vapour sensing properties of WO3 thick films. In this work, the WO3 thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these ...

  2. New Method of Vapour Discrimination Using the Thickness Shear Mode (TSM Resonator

    Directory of Open Access Journals (Sweden)

    J. Siddiqi

    2003-06-01

    Full Text Available The Impedance analysis technique complimented with curve fitting software was used to monitor changes in film properties of Thickness Shear Mode (TSM resonator on vapour exposure. The approach demonstrates how sensor selectivity can be achieved through unique changes in film viscosity caused by organic vapour adsorption.

  3. Utility of DMSP-SSM/I for integrated water vapour over the Indian seas

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging Solutions)

    Recent algorithms for Special Sensor Microwave/Imager (DMSP-SSM/I) satellite data are used for estimating integrated water vapour over the Indian seas. Integrated water vapour obtained from these algorithms is compared with that derived from radiosonde observations at Minicoy and Port. Blair islands. Algorithm-3 of ...

  4. CdS sensitized TiO{sub 2} film for photocatalytic reduction of Cr(VI) by microwave-assisted chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinjuan; Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn; Lv, Tian; Sun, Zhuo

    2014-01-15

    Highlights: • CdS sensitized TiO{sub 2} films are synthesized by microwave-assisted deposition method. • The photocatalytic reduction of Cr(VI) by CdS sensitized TiO{sub 2} film is investigated. • A high Cr(VI) reduction rate of 93% is achieved under white LED light irradiation. -- Abstract: CdS quantum dots (QDs) sensitized TiO{sub 2} films were successfully synthesized using one-step microwave assisted chemical bath deposition method, which allows a facile and rapid deposition and integration between CdS QDs and TiO{sub 2} films. The photocatalytic performance of the films fabricated using CdS precursor solutions with different concentrations in the reduction of Cr(VI) under white light emitting diode (LED) light irradiation was investigated. The results show that the CdS sensitization can enhance the photocatalytic performance of TiO{sub 2} film with a maximum reduction rate of 93% for 240 min under white LED light irradiation as compared with the pure TiO{sub 2} film (31%) due to the increase of light absorption and the reduction of recombination of the injected electrons from CdS to TiO{sub 2}.

  5. Olive oil pilot-production assisted by pulsed electric field: impact on extraction yield, chemical parameters and sensory properties.

    Science.gov (United States)

    Puértolas, Eduardo; Martínez de Marañón, Iñigo

    2015-01-15

    The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2 kV/cm; 11.25 kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Water mobility within arabinoxylan and β-glucan films studied by NMR and dynamic vapour sorption.

    Science.gov (United States)

    Ying, Ruifeng; Barron, Cécile; Saulnier, Luc; Rondeau-Mouro, Corinne

    2011-11-01

    The main purpose of this research was to determine the impact of the structure and organisation of polysaccharides on the hydration properties of the cell walls of cereal grains. In order to remodel the lamellar assembly of arabinoxylan (AX) and (1 → 3)(1 → 4)-β-D-glucan (BG) within the endosperm cell walls, films were prepared and analysed using dynamic vapour sorption and time domain nuclear magnetic resonance spectroscopy. The water diffusivities within the AX and BG films were measured at 20 °C by observing the water sorption kinetics within a mathematical model based on Fick's second law. The evolution of spin-spin relaxation times of water protons measured by increasing the temperature is explained by the additional contributions of motion of the protons of polysaccharides and/or rapid chemical exchanges of protons between water and hydroxyl groups of polysaccharides. The difference between patterns of water behaviour within the AX and BG films can be related to the difference in their nanostructures. The smaller nanopores of the BG films cause their nanostructure to be more compact. Copyright © 2011 Society of Chemical Industry.

  7. Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours

    Directory of Open Access Journals (Sweden)

    T. Petäjä

    2005-01-01

    Full Text Available Hygroscopicity (i.e. water vapour affinity of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic particles is expected to increase their hygrocopicity and hence their cloud condensation nuclei formation potential. In this study, differences in the hygroscopic and ethanol uptake properties of ultrafine aerosol particles in the Arctic air masses with a different exposure to anthropogenic sulfur pollution were examined. The main discovery was that Aitken mode particles having been exposed to polluted air were more hygroscopic and less soluble to ethanol than after transport in clean air. This aging process was attributed to sulphur dioxide oxidation and subsequent condensation during the transport of these particle to our measurement site. The hygroscopicity of nucleation mode aerosol particles, on the other hand, was approximately the same in all the cases, being indicative of a relatively similar chemical composition despite the differences in air mass transport routes. These particles had also been produced closer to the observation site typically 3–8 h prior to sampling. Apparently, these particles did not have an opportunity to accumulate sulphuric acid on their way to the site, but instead their chemical composition (hygroscopicity and ethanol solubility resembled that of particles produced in the local or semi-regional ambient conditions.

  8. Can painted glass felt or glass fibre cloth be used as vapour barrier?

    DEFF Research Database (Denmark)

    El-Khattam, Amira; Andersen, Mie Them; Kielsgaard Hansen, Kurt

    2014-01-01

    it is essential to know how much influence a surface treatment has on the water vapour transport. Traditionally, there has been most focus on paints that affect the permeability as little as possible. However, sometimes water vapour resistance is desirable. Especially, this is relevant in existing buildings...... on the ceiling e.g. as an ordinary paint. This paper presents the results of an investigation of the water vapour resistance of surface treatments which are commonly used in-door. The water vapour resistance was measured by the cup method. Aerated concrete was investigated with and without various surface...... treatments. The surface treatments were glass felt or glass fibre cloth with different types of paints or just paint. The paint types were acrylic paint and silicate paint. The results show that the paint type has high influence on the water vapour resistance while the underlay i.e. glass felt or glass fibre...

  9. Optimization for ultrasound-assisted extraction of polysaccharides with chemical composition and antioxidant activity from the Artemisia sphaerocephala Krasch seeds.

    Science.gov (United States)

    Zheng, Quan; Ren, Daoyuan; Yang, Nana; Yang, Xingbin

    2016-10-01

    Artemisia sphaerocephala Krasch seeds polysaccharides have been reported to have a variety of important biological activities. However, effective extraction of Artemisia sphaerocephala Krasch seeds polysaccharides is still an unsolved issue. In this study, the orthogonal rotatable central composite design was employed to optimize ultrasound-assisted extraction conditions of Artemisia sphaerocephala Krasch seeds polysaccharides. Based on a single-factor analysis method, ultrasonic power, extraction time, solid-liquid ratio and extraction temperature were shown to significantly affect the yield of polysaccharides extracted from the A. sphaerocephala Krasch seeds. The optimal conditions for extraction of Artemisia sphaerocephala Krasch seeds polysaccharides were determined as following: ultrasonic power 243W, extraction time 125min, solid-liquid ratio 64:1 and extraction temperature 64°C, where the experimental yield was 14.78%, which was well matched with the predicted value of 14.81%. Furthermore, ASKP was identified as a typical heteropolysaccharide with d-galacturonic acid (38.8%) d-galactose (20.2%) and d-xylose (15.5%) being the main constitutive monosaccharides. Moreover, Artemisia sphaerocephala Krasch seeds polysaccharides exhibited high total reducing power and considerable scavenging activities on DPPH, hydroxyl and superoxide radicals, in a concentration-dependent manner in vitro. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Bi-assisted chemical etching of silicon in HF/Co(NO{sub 3}){sub 2} solution

    Energy Technology Data Exchange (ETDEWEB)

    Megouda, N. [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Hadjersi, T. [Unite de Developpement de la Technologie du Silicium (UDTS), 2, Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria)], E-mail: hadjersi@yahoo.com; Elkechai, O.; Douani, R. [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Guerbous, L. [Centre de Recherche Nucleaire d' Alger (CRNA) COMENA 2, Bd. Frantz Fanon, Alger (Algeria)

    2009-03-15

    The morphology and the photoluminescence (PL) of Bi-assisted electroless etched p-type silicon in HF-Co(NO{sub 3}){sub 2}-H{sub 2}O solution as a function of etching time were studied. The scanning electron microscopy (SEM) observations have shown that the morphology of etched layers strongly depends on the etching time and it was observed that macropores filled with silicon crystallites are formed for etching time higher than 50 min. Moreover, it was found that the PL spectra show a red emission with a peak centred at 640 nm. The PL peak intensity reaches a maximum for etching time of 50 min, and then it decreases with increasing etching time. The Fourier transform infrared (FTIR) measurements have shown a strong increase in intensities of the relevant Si-H and in the amount of oxide (absorption band at 1070 cm{sup -1}) for long etching time which was ascribed to an increase in the number of Si crystallites formed in the macropores.

  11. In Vitro Durability - Pivot bearing with Diamond Like Carbon for Ventricular Assist Devices

    CERN Document Server

    de Sá, Rosa Corrêa Leoncio; Leão, Tarcísio Fernandes; da Silva, Evandro Drigo; da Fonseca, Jeison Willian Gomes; da Silva, Bruno Utiyama; Leal, Edir Branzoni; Moro, João Roberto; de Andrade, Aron José Pazin; Bock, Eduardo Guy Perpétuo

    2015-01-01

    Institute Dante Pazzanese of Cardiology (IDPC) develops Ventricular Assist Devices (VAD) that can stabilize the hemodynamics of patients with severe heart failure before, during and/or after the medical practice; can be temporary or permanent. The ADV's centrifugal basically consist of a rotor suspended for system pivoting bearing; the PIVOT is the axis with movement of rotational and the bearing is the bearing surface. As a whole system of an implantable VAD should be made of long-life biomaterial so that there is no degradation or deformation during application time; surface modification techniques have been widely studied and implemented to improve properties such as biocompatibility and durability of applicable materials. The Chemical Vapour Deposition technique allows substrates having melting point higher than 300 {\\deg}C to be coated, encapsulated, with a diamond like carbon film (DLC); The test simulated the actual conditions in which the system of support remains while applying a ADV. The results hav...

  12. Chemically assisted femtosecond laser machining for applications in LiNbO3 and LiTaO3

    Science.gov (United States)

    Sivarajah, Prasahnt; Werley, Christopher A.; Ofori-Okai, Benjamin K.; Nelson, Keith A.

    2013-09-01

    We introduce and optimize a fabrication procedure that employs both femtosecond laser machining and hydrofluoric acid etching for cutting holes or voids in slabs of lithium niobate and lithium tantalate. The fabricated structures have 3 μm lateral resolution, a lateral extent of at least several millimeters, and cut depths of up to 100 μm. Excellent surface quality is achieved by initially protecting the optical surface with a sacrificial silicon dioxide layer that is later removed during chemical etching. To optimize cut quality and machining speed, we explored various laser-machining parameters, including laser polarization, repetition rate, pulse duration, pulse energy, exposure time, and focusing, as well as scanning, protective coating, and etching procedures. The resulting structures significantly broaden the capabilities of terahertz polaritonics, in which lithium niobate and lithium tantalate are used for terahertz wave generation, imaging, and control. The approach should be applicable to a wide range of materials that are difficult to process by conventional methods.

  13. Transformation of oil palm fronds into pentose sugars using copper (II) sulfate pentahydrate with the assistance of chemical additive.

    Science.gov (United States)

    Loow, Yu-Loong; Wu, Ta Yeong

    2017-05-22

    Among the chemical pretreatments available for pretreating biomass, the inorganic salt is considered to be a relatively new but simple reagent that offers comparable pentose (C5) sugar recoveries as the conventional dilute acid hydrolysis. This study investigated the effects of different concentrations (1.5-6.0% (v/v)) of H2O2 or Na2S2O8 in facilitating CuSO4·5H2O pretreatment for improving pentose sugar recovery from oil palm fronds. The best result was observed when 0.2 mol/L of CuSO4·5H2O was integrated with 4.5% (v/v) of Na2S2O8 to recover 8.2 and 0.9 g/L of monomeric xylose and arabinose, respectively in the liquid fraction. On the other hand, an addition of 1.5% (v/v) of H2O2 yielded approximately 74% lesser total pentose sugars as compared to using 4.5% (v/v) Na2S2O8. By using CuSO4·5H2O alone (control), only 0.8 and 1.0 g/L xylose and arabinose, respectively could be achieved. The results mirrored the importance of using chemical additives together with the inorganic salt pretreatment of oil palm fronds. Thus, an addition of 4.5% (v/v) of Na2S2O8 during CuSO4·5H2O pretreatment of oil palm fronds at 120 °C and 30 min was able to attain a total pentose sugar yield up to ∼40%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Stratospheric water vapour as tracer for Vortex filamentation in the Arctic winter 2002/2003

    Directory of Open Access Journals (Sweden)

    M. Müller

    2003-01-01

    Full Text Available Balloon-borne frost point hygrometers measured three high-resolution profiles of stratospheric water vapour above Ny-Ålesund, Spitsbergen during winter 2002/2003. The profiles obtained on 12 December 2002 and on 17 January 2003 provide an insight into the vertical distribution of water vapour in the core of the polar vortex. The water vapour sounding on 11 February 2003 was obtained within the vortex edge region of the lower stratosphere. Here, a significant reduction of water vapour mixing ratio was observed between 16 and 19 km. The stratospheric temperatures indicate that this dehydration was not caused by the presence of polar stratospheric clouds or earlier PSC particle sedimentation. Ozone observations on this day indicate a large scale movement of the polar vortex and show laminae in the same altitude range as the water vapour profile. The link between the observed water vapour reduction and filaments in the vortex edge region is indicated in the results of the semi-lagrangian advection model MIMOSA, which show that adjacent filaments of polar and mid latitude air can be identified above the Spitsbergen region. A vertical cross-section produced by the MIMOSA model reveals that the water vapour sonde flew through polar air in the lowest part of the stratosphere below 425 K, then passed through filaments of mid latitude air with lower water vapour concentrations, before it finally entered the polar vortex above 450 K. These results indicate that on 11 February 2003 the frost point hygrometer measured different water vapour concentrations as the sonde detected air with different origins. Instead of being linked to dehydration due to PSC particle sedimentation, the local reduction in the stratospheric water vapour profile was in this case caused by dynamical processes in the polar stratosphere.

  15. Microwave-assisted catalytic fast pyrolysis of biomass for bio-oil production using chemical vapor deposition modified HZSM-5 catalyst.

    Science.gov (United States)

    Zhang, Bo; Zhong, Zhaoping; Chen, Paul; Ruan, Roger

    2015-12-01

    Chemical vapor deposition with tetra-ethyl-orthosilicate as the modifier was applied to deposit the external acid sites of HZSM-5, and the modified HZSM-5 samples were used for the microwave-assisted catalytic fast pyrolysis (MACFP) of biomass for bio-oil production. The experimental results showed that the external acid sites of HZSM-5 decreased significantly when SiO2 deposited amount increased from 0% to 5.9%. For product distribution, the coke yield decreased, the oil fraction yield decreased at first and then increased, and the yields of water and gas first increased and then decreased over the range of SiO2 deposited amount studied. For chemical compositions in oil fraction, the relative contents of aliphatic hydrocarbons, aromatic hydrocarbons and oxygen-containing aromatic compounds first increased to maximum values and then decreased, while the relative content of oxygen-containing aliphatic compounds first decreased and then increased with increasing SiO2 deposited amount. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Hierarchically arranged helical fibre actuators driven by solvents and vapours

    Science.gov (United States)

    Chen, Peining; Xu, Yifan; He, Sisi; Sun, Xuemei; Pan, Shaowu; Deng, Jue; Chen, Daoyong; Peng, Huisheng

    2015-12-01

    Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes. Primary fibres consisting of helical assemblies of multiwalled carbon nanotubes are twisted together to form the helical actuating fibres. The nanoscale gaps between the nanotubes and micrometre-scale gaps among the primary fibres contribute to the rapid response and large actuation stroke of the actuating fibres. The compact coils allow the actuating fibre to rotate reversibly. We show that these fibres, which are lightweight, flexible and strong, are suitable for a variety of applications such as energy-harvesting generators, deformable sensing springs and smart textiles.

  17. Atmospheric pressure vapour phase decomposition: a proof of principle.

    Science.gov (United States)

    Cinosi, Amedeo; Andriollo, Nunzio; Tibaldi, Francesca; Monticelli, Damiano

    2012-11-15

    In the present work we demonstrated that the digestion of difficult matrices (high boiling petrochemical fractions and distillation bottoms) can be achieved by oxidation with nitric acid vapours at atmospheric pressure employing simple laboratory glassware. The application of this procedure as a digestion method prior to Total Reflection X-Ray Fluorescence (TXRF) is presented, although the employment of other detection techniques may be foreseen. The method ensured a fast, less than half an hour, treatment time and detection limits in the range 20-100 μg/kg for As, Bi, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn, whereas higher values were obtained for Ba, Ca, K, P, Rh, Ti and V (0.3-3 mg/kg). The potentialities and limitations of this procedure were discussed: the application to a broad range of matrices may be foreseen. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. A comparison of the efficacy of organic and mixed-organic polymers with polyaluminium chloride in chemically assisted primary sedimentation (CAPS).

    Science.gov (United States)

    De Feo, G; Galasso, M; Landi, R; Donnarumma, A; De Gisi, S

    2013-01-01

    CAPS is the acronym for chemically assisted primary sedimentation, which consists of adding chemicals to raw urban wastewater to increase the efficacy of coagulation, flocculation and sedimentation. The principal benefits of CAPS are: upgrading of urban wastewater treatment plants; increasing efficacy of primary sedimentation; and the major production of energy from the anaerobic digestion of primary sludge. Metal coagulants are usually used because they are both effective and cheap, but they can cause damage to the biological processes of anaerobic digestion. Generally, biodegradable compounds do not have these drawbacks, but they are comparatively more expensive. Both metal coagulants and biodegradable compounds have preferential and penalizing properties in terms of CAPS application. The problem can be solved by means of a multi-criteria analysis. For this purpose, a series of tests was performed in order to compare the efficacy of several organic and mixed-organic polymers with that of polyaluminium chloride (PACl) under specific conditions. The multi-criteria analysis was carried out coupling the simple additive weighting method with the paired comparison technique as a tool to evaluate the criteria priorities. Five criteria with the following priorities were used: chemical oxygen demand (COD) removal > turbidity, SV60 > coagulant dose, and coagulant cost. The PACl was the best alternative in 70% of the cases. The CAPS process using PACl made it possible to obtain an average COD removal of 68% compared with 38% obtained, on average, with natural sedimentation and 61% obtained, on average, with the best PACl alternatives (cationic polyacrylamide, natural cationic polymer, dicyandiamide resin).

  19. Evaluating the virucidal efficacy of hydrogen peroxide vapour.

    Science.gov (United States)

    Goyal, S M; Chander, Y; Yezli, S; Otter, J A

    2014-04-01

    Surface contamination has been implicated in the transmission of certain viruses, and surface disinfection can be an effective measure to interrupt the spread of these agents. To evaluate the in-vitro efficacy of hydrogen peroxide vapour (HPV), a vapour-phase disinfection method, for the inactivation of a number of structurally distinct viruses of importance in the healthcare, veterinary and public sectors. The viruses studied were: feline calicivirus (FCV, a norovirus surrogate); human adenovirus type 1; transmissible gastroenteritis coronavirus of pigs (TGEV, a severe acute respiratory syndrome coronavirus [SARS-CoV] surrogate); avian influenza virus (AIV); and swine influenza virus (SwIV). The viruses were dried on stainless steel discs in 20- or 40-μL aliquots and exposed to HPV produced by a Clarus L generator (Bioquell, Horsham, PA, USA) in a 0.2-m(3) environmental chamber. Three vaporized volumes of hydrogen peroxide were tested in triplicate for each virus: 25, 27 and 33 mL. No viable viruses were identified after HPV exposure at any of the vaporized volumes tested. HPV was virucidal (>4-log reduction) against FCV, adenovirus, TGEV and AIV at the lowest vaporized volume tested (25 mL). For SwIV, due to low virus titre on the control discs, >3.8-log reduction was shown for the 25-mL vaporized volume and >4-log reduction was shown for the 27-mL and 33-mL vaporized volumes. HPV was virucidal for structurally distinct viruses dried on surfaces, suggesting that HPV can be considered for the disinfection of virus-contaminated surfaces. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  20. Quantum dots assisted photocatalysis for the chemiluminometric determination of chemical oxygen demand using a single interface flow system.

    Science.gov (United States)

    Silvestre, Cristina I C; Frigerio, Christian; Santos, João L M; Lima, José L F C

    2011-08-12

    A novel flow method for the determination of chemical oxygen demand (COD) is proposed in this work. It relies on the combination of a fully automated single interface flow system, an on-line UV photocatalytic unit and quantum dot (QD) nanotechnology. The developed approach takes advantage of CdTe nanocrystals capacity to generate strong oxidizing species upon irradiation with UV light, which fostered a fast catalytic degradation of the organic compounds. Luminol was used as a chemiluminescence (CL) probe for indirect COD assessment, since it is easily oxidized by the QD generated species yielding a strong CL emission that is quenched in the presence of the organic matter. The proposed methodology allowed the determination of COD concentrations between 1 and 35 mg L(-1), with good precision (R.S.D.<1.1%, n=3) and a sampling frequency of about 33 h(-1). The procedure was applied to the determination of COD in wastewater certified reference materials and the obtained results showed an excellent agreement with the certified values. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Numerical analysis of the interaction between high-pressure resin spray and wood chips in a vapour stream

    Directory of Open Access Journals (Sweden)

    Massimo Milani

    2016-04-01

    Full Text Available This article investigates the interaction between the resin spray and the wood chips in a vapour stream using a multi-phase multi-component computational fluid dynamics approach. The interaction between the spray and the chips is one of the main issues in the industrial process for manufacturing medium density fibre boards. Thus, the optimization of this process can lead to important benefits, such as the reduction in the emission of formaldehyde-based toxic chemicals, the reduction in energy consumption in the blending process and energy saving in the fibreboard drying process. First step of the study is the numerical analysis of the resin injector in order to extend the experimental measurements carried out with water to the resin spray. The effects of the injector’s geometrical features on the spray formation are highlighted under different injection pressure values and needle displacements. Afterwards, the results obtained in the analysis of the single injector are used for the complete simulation of multi-injector rail where the mixing of the resin spray and wood chips takes place. The influence of the main operating conditions, such as the vapour and the wood chip flow rates, on the resin distribution is addressed in order to optimize the resination process.

  2. Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave-Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni2+ Ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    M. Makeswari

    2013-01-01

    Full Text Available The preparation of activated carbon (AC from Ricinus communis leaves was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted zinc chloride. Optimized parameters were radiation power of 100 W, radiation time of 8 min, concentration of zinc chloride of 30% by volume, and impregnation time of 24 h, respectively. The surface characteristics of the AC prepared under optimized conditions were examined by pHZPC, SEM-EDAX, XRD, and FTIR. Competitive adsorption of Ni2+ ions on Ricinus communis leaves by microwave assisted zinc chloride chemical activation (ZLRC present in binary and ternary mixture was compared with the single metal solution. The effects of the presence of one metal ion on the adsorption of the other metal ion were investigated. The experimental results indicated that the uptake capacity of one metal ion was reduced by the presence of the other metal ion. The extent of adsorption capacity of the binary and ternary metal ions tested on ZLRC was low (48–69% as compared to single metal ions. Comparisons with the biosorption of Ni2+ ions by the biomass of ZLRC in the binary (48.98–68.41%-~Ni-Cu and 69.76–66.29%-~Ni-Cr and ternary solution (67.32–57.07%-~Ni–Cu and Cr could lead to the conclusion that biosorption of Ni2+ ions was reduced by the influence of Cu2+ and Cr3+ ions. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The adsorption process follows the pseudo-second-order kinetic model.

  3. Mixing of multiple metal vapours into an arc plasma in gas tungsten arc welding of stainless steel

    Science.gov (United States)

    Park, Hunkwan; Trautmann, Marcus; Tanaka, Keigo; Tanaka, Manabu; Murphy, Anthony B.

    2017-11-01

    A computational model of the mixing of multiple metal vapours, formed by vaporization of the surface of an alloy workpiece, into the thermal arc plasma in gas tungsten arc welding (GTAW) is presented. The model incorporates the combined diffusion coefficient method extended to allow treatment of three gases, and is applied to treat the transport of both chromium and iron vapour in the helium arc plasma. In contrast to previous models of GTAW, which predict that metal vapours are swept away to the edge of the arc by the plasma flow, it is found that the metal vapours penetrate strongly into the arc plasma, reaching the cathode region. The predicted results are consistent with published measurements of the intensity of atomic line radiation from the metal vapours. The concentration of chromium vapour is predicted to be higher than that of iron vapour due to its larger vaporization rate. An accumulation of chromium vapour is predicted to occur on the cathode at about 1.5 mm from the cathode tip, in agreement with published measurements. The arc temperature is predicted to be strongly reduced due to the strong radiative emission from the metal vapours. The driving forces causing the diffusion of metal vapours into the helium arc are examined, and it is found that diffusion due to the applied electric field (cataphoresis) is dominant. This is explained in terms of large ionization energies and the small mass of helium compared to those of the metal vapours.

  4. Rapid and sensitive serum glucose determination using chemical labeling coupled with black phosphorus-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Qing; Yu, Lei; Qi, Chu-Bo; Ding, Jun; He, Xiao-Mei; Wang, Ren-Qi; Feng, Yu-Qi

    2018-01-01

    Monitoring the concentration of blood glucose in patients is a key component of good medical diagnoses. Therefore, developing an accurate, rapid and sensitive strategy for monitoring blood glucose is of vital importance. We proposed a strategy for serum glucose determination combining 2-(4-boronobenzyl) isoquinolin-2-ium bromide chemical labeling with black phosphorus assisted laser desorption ionization-time of flight mass spectrometry (CL-BP/ALDI-TOF MS). The entire analytical process consisted of 1min of protein precipitation and 3min of chemical labeling in a microwave oven prior to the BP/ALDI-TOF MS analysis. The analysis can be completed in 5min with high throughput and extremely low sample consumption. Good linearity for glucose was obtained with a correlation coefficient (R) of 0.9986. The limit of detection (LOD) and limit of quantification (LOQ) were 11.5 fmol and 37.5 fmol, respectively. Satisfied reproducibility and reliability were gained by evaluation of the intra- and inter-day precisions with relative standard deviations (RSDs) less than 7.2% and relative recoveries ranging from 87.1% to 108.1%, respectively. The proposed strategy was also applied for the analysis of endogenous glucose in various serum samples and the results were consistent with those obtained using the hexokinase method in a clinical laboratory. Considering the results, the proposed CL-BP/ALDI-TOF MS strategy has proven to be reliable, fast, and sensitive for quantitative analysis of serum glucose. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Recent advances in controlled synthesis of two-dimensional transition metal dichalcogenides via vapour deposition techniques

    KAUST Repository

    Shi, Yumeng

    2014-10-20

    In recent years there have been many breakthroughs in two-dimensional (2D) nanomaterials, among which the transition metal dichalcogenides (TMDs) attract significant attention owing to their unusual properties associated with their strictly defined dimensionalities. TMD materials with a generalized formula of MX2, where M is a transition metal and X is a chalcogen, represent a diverse and largely untapped source of 2D systems. Semiconducting TMD monolayers such as MoS2, MoSe2, WSe2 and WS2 have been demonstrated to be feasible for future electronics and optoelectronics. The exotic electronic properties and high specific surface areas of 2D TMDs offer unlimited potential in various fields including sensing, catalysis, and energy storage applications. Very recently, the chemical vapour deposition technique (CVD) has shown great promise to generate high-quality TMD layers with a scalable size, controllable thickness and excellent electronic properties. Wafer-scale deposition of mono to few layer TMD films has been obtained. Despite the initial success in the CVD synthesis of TMDs, substantial research studies on extending the methodology open up a new way for substitution doping, formation of monolayer alloys and producing TMD stacking structures or superlattices. In this tutorial review, we will introduce the latest development of the synthesis of monolayer TMDs by CVD approaches.

  6. Metal-Nonmetal Transition and Homogeneous Nucleation of Mercury Vapour

    Science.gov (United States)

    Uchtmann, H.; Rademann, K.; Hensel, F.

    The paper presents ionization potentials of mercury clusters obtained by photoelectron spectroscopy which provide evidence that a size-dependent gradual transition from van der Waals-type to metallic interaction occurs in Hgx-clusters for × > 13. In order to probe the role of this nonmetal to metal transition in the homogeneous nucleation process of supersaturated mercury vapour we have determined the supersaturation necessary for homogeneous condensation of mercury vapour in the temperature range 250 to 320 K. The measurements were made using an upward thermal diffusion cloud chamber. The results demonstrate that none of the current theories for homogeneous nucleation satisfactorily predict the observed critical supersaturations. The measured values are about 3 orders of magnitude lower than the values predicted by the conventional Becker-Döring-Zeldovitch-theory.Translated AbstractMetall-Nichtmetallübergang und homogene Keimbildung bei QuecksilberdampfEs werden photoelektronenspektroskopische Messungen der Ionisationspotentiale von im Molekularstrahl synthetisierten Quecksilberclustern als Funktion der Größe beschrieben. Sie zeigen, daß ein größenabhängiger kontinuierlicher Übergang von van der Waals-Bindung zu metallischer Bindung für Cluster mit mehr als 13 Hg-Atomen auftritt. Um erste Informationen über den Einfluß dieses Übergangs von nichtmetallischem zu metallischem Verhalten auf den Keimbildungsprozeß in übersättigten Quecksilberdämpfen zu erhalten, werden zusätzlich Untersuchungen der homogenen Kondensation von übersättigten Quecksilberdämpfen im Temperaturbereich zwischen 250 bis 320 K mit einer Diffusionsnebelkammer berichtet. Die erhaltenen Ergebnisse können mit keiner der existierenden Theorien für die homogene Kondensation beschrieben werden. Die beobachteten Werte für die die homogene Kondensation auslösende kritische Übersättigung sind um drei Größenordnungen größer als die mit der klassischen Becker

  7. Influence of collisional rate coefficients on water vapour excitation

    Science.gov (United States)

    Daniel, F.; Goicoechea, J. R.; Cernicharo, J.; Dubernet, M.-L.; Faure, A.

    2012-11-01

    Context. Water is a key molecule in many astrophysical studies that deal with star or planet forming regions, evolved stars, and galaxies. Its high dipole moment makes this molecule subthermally populated under the typical conditions of most astrophysical objects. This motivated calculation of various sets of collisional rate coefficients (CRC) for H2O (with He or H2), which are needed to model its rotational excitation and line emission. Aims: The most accurate set of CRC are the quantum rates that involve H2. However, they have been published only recently, and less accurate CRC (quantum with He or quantum classical trajectory (QCT) with H2) were used in many studies before that. This work aims to underline the impact that the new available set of CRC have on interpretations of water vapour observations. Methods: We performed accurate non-local, non-LTE radiative transfer calculations using different sets of CRC to predict the line intensities from transitions that involve the lowest energy levels of H2O (E find that the intensities based on the quantum and QCT CRC are in good agreement. However, at relatively low H2 volume density (n(H2) find differences in the predicted line intensities of up to a factor of ~3 for the bulk of the lines. Most of the recent studies interpreting early Herschel Space Observatory spectra have used the QCT CRC. Our results show that, although the global conclusions from those studies will not be drastically changed, each case has to be considered individually, since depending on the physical conditions, the use of the QCT CRC may lead to a mis-estimate of the water vapour abundance of up to a factor of ~3. Additionally, the comparison of the quantum state-to-state and thermalised CRC, including the description of the population of the H2 rotational levels, show that above TK ~ 100 K, large differences are expected from those two sets for the p-H2 symmetry. Finally, we find that at low temperature (i.e. TK < 100 K) modelled line

  8. Automated radioanalytical system incorporating microwave-assisted sample preparation, chemical separation, and online radiometric detection for the monitoring of total 99Tc in nuclear waste processing streams.

    Science.gov (United States)

    Egorov, Oleg B; O'Hara, Matthew J; Grate, Jay W

    2012-04-03

    An automated fluidic instrument is described that rapidly determines the total (99)Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the (99)Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of (99)Tc. We developed a preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of (99)Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site.

  9. Effects of intermittent atomization on the properties of Al-doped ZnO thin films deposited by aerosol-assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Linjie; Wang, Lixin [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Qin, Xiujuan, E-mail: qinxj@ysu.edu.cn [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Cui, Li [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Shao, Guangjie [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2016-04-30

    Al-doped ZnO (AZO) thin films were prepared on glass substrates with different atomization interval times by aerosol-assisted chemical vapor deposition method. The structure, morphology, and optical and electrical properties were investigated by X-ray diffractometer, atomic force microscope, UV-vis double beam spectrophotometer and 4 point probe method. ZnO thin films exhibited strong growth orientation along the (002) plane and the crystalline was affected by the atomization interval time. All the films had high transmittance and the films with interval times of 2 min and 4 min had good haze values for the transparent conducting oxide silicon solar cell applications. The AZO thin film had the best optical and electrical properties when the atomization interval time was 4 min. This is very important for the optoelectronic device applications. The surface morphology of AZO films depended on the atomization interval time. - Highlights: • Intermittent atomization is proved to be an effective measure. • Atomization interval time has an important influence on the crystallinity of films. • The surface morphology of ZnO films depends on atomization interval time. • Different hazes can be obtained by changing the atomization interval time.

  10. Microwave assisted chemical bath deposition of vertically aligned ZnO nanorods on a variety of substrates seeded by PVA-Zn(OH){sub 2} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, J.J., E-mail: j1j2h72@yahoo.com [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Physics, College of Science, University of Basrah, Basrah (Iraq); Mahdi, M.A. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Physics, College of Science, University of Basrah, Basrah (Iraq); Chin, C.W.; Hassan, Z.; Abu-Hassan, H. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2012-03-01

    Vertically aligned zinc oxide (ZnO) nanorods were synthesized successfully on p-type GaN, c-lattice Al{sub 2}O{sub 3}, ITO glass, and quartz single crystal substrates using the microwave-assisted chemical bath deposition method. All substrates were seeded with a PVA-Zn(OH){sub 2} nanocomposites layer prior to nanorods growth. The effect of substrate type on the vertically alignment and morphology of the zinc oxide nanorods was studied. The diameter of the grown ZnO nanorods ranged from 30 to 170 nm. Their structural quality and morphology were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which revealed hexagonal wurtzite structures perpendicular to the substrate along the z-axis in the direction of (0 0 2) plane. Photoluminescence (PL) measurements of the grown ZnO nanorods on all substrates exhibited high UV peak intensity compared to broad visible peak. Raman scattering studies were conducted to estimate the lattice vibration modes.

  11. Effect of Ag on structural, optical and luminescence properties of ZnS nanoparticles synthesized by microwave-assisted chemical route

    Science.gov (United States)

    Patel, Kamakshi; Deshpande, M. P.; Chaki, S. H.

    2017-05-01

    Silver (Ag)-doped (0, 5, 10 and 15%) ZnS nanoparticles are synthesized by microwave-assisted chemical route using polyvinylpyrrolidone (PVP). We study the compositional, structural, optical and luminescence properties by energy-dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and photoluminescence (PL) spectroscopy, respectively. Synthesized Ag-doped ZnS nanoparticles do not possess any impurity as seen from EDAX spectra. TEM images show particles to be in spherical shape with agglomeration, and corresponding selected area electron diffraction (SAED) pattern showed that they are polycrystalline in nature. Allowed LO and TO modes corresponding to cubic phase for all the samples are observed in Raman spectra. FTIR spectroscopy is used to study the interaction between PVP and as-synthesized nanoparticles. Blue shift can be seen in pure and Ag-doped ZnS nanoparticles compared to bulk ZnS as seen from absorption spectra. Green emission is observed in PL spectra due to Ag doping without showing any quenching behavior.

  12. Pervaporation and vapour permeation of methanol and MTBE through a microporous methylated silica membrane

    NARCIS (Netherlands)

    de Bruijn, F.T.

    2006-01-01

    The combination of conventional unit operations with pervaporation or vapour permeation membrane separation processes offers opportunities for process intensification in terms of augmenting capacity and decreasing energy consumption of conventional unit operations. The MTBE production process is an

  13. Signal transduction pathway(s) in guard cells after prolonged exposure to low vapour pressure deficit

    NARCIS (Netherlands)

    Ali Niaei Fard, S.

    2014-01-01

    Keywords: Abscisic acid, Arabidopsis thaliana, calcium, CYP707As, desiccation, environmental factors, guard cells’ signalling pathway, hydrogen peroxide, natural variation, nitric oxide, photosystem II efficiency, RD29A, relative water content, secondary messengers, stomata, vapour pressure

  14. Latent heat flux measurements over complex terrain by airborne water vapour and wind lidars

    National Research Council Canada - National Science Library

    Kiemle, Christoph; Wirth, Martin; Fix, Andreas; Rahm, Stephan; Corsmeier, Ulrich; Di Girolamo, Paolo

    2011-01-01

    Vertical profiles of the latent heat flux in a convective boundary layer (CBL) are obtained for the first time over complex terrain with airborne water vapour differential absorption lidar and Doppler wind lidar...

  15. Quantifying the water vapour feedback associated with post-Pinatubo global cooling

    Energy Technology Data Exchange (ETDEWEB)

    Forster, P.M. de [NOAA Aeronomy Laboratory, Boulder, Colorado (United States); Department of Meteorology, University of Reading, Reading (United Kingdom); Collins, M. [Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, Reading (United Kingdom)

    2004-08-01

    There is an ongoing important debate about the role of water vapour in climate change. Predictions of future climate change depend strongly on the magnitude of the water vapour feedback and until now models have almost exclusively been relied upon to quantify this feedback. In this work we employ observations of water vapour changes, together with detailed radiative calculations to estimate the water vapour feedback for the case of the Mt. Pinatubo eruption. We then compare our observed estimate with that calculated from a relatively large ensemble of simulations from a complex coupled climate model. We calculate an observed water vapour feedback parameter of -1.6 Wm{sup -2} K{sup -1}, with uncertainty placing the feedback parameter between -0.9 to -2.5 Wm{sup -2} K{sup -1}. The uncertain is principally from natural climate variations that contaminate the volcanic cooling. The observed estimates are consistent with that found in the climate model, with the ensemble average model feedback parameter being -2.0 Wm{sup -2} K{sup -1}, with a 5-95% range of -0.4 to -3.6 Wm{sup -2} K{sup -1} (as in the case of the observations, the spread is due to an inability to separate the forced response from natural variability). However, in both the upper troposphere and Southern Hemisphere the observed model water vapour response differs markedly from the observations. The observed range represents a 40%-400% increase in the magnitude of surface temperature change when compared to a fixed water vapour response and is in good agreement with values found in other studies. Variability, both in the observed value and in the climate model's feedback parameter, between different ensemble members, suggests that the long-term water vapour feedback associated with global climate change could still be a factor of 2 or 3 different than the mean observed value found here and the model water vapour feedback could be quite different from this value; although a small water vapour feedback

  16. Vapour and air bubble collapse analysis in viscous compressible water

    Directory of Open Access Journals (Sweden)

    Gil Bazanini

    2001-01-01

    Full Text Available Numerical simulations of the collapse of bubbles (or cavities are shown, using the finite difference method, taking into account the compressibility of the liquid, expected to occur in the final stages of the collapse process. Results are compared with experimental and theoretical data for incompressible liquids, to see the influence of the compressibility of the water in the bubble collapse. Pressure fields values are calculated in an area of 800 x 800 mm, for the case of one bubble under the hypothesis of spherical symmetry. Results are shown as radius versus time curves for the collapse (to compare collapse times, and pressure curves in the plane, for pressure fields. Such calculations are new because of their general point of view, since the existing works do not take into account the existence of vapour in the bubble, neither show the pressure fields seen here. It is also expected to see the influence of the compressibility of the water in the collapse time, and in the pressure field, when comparing pressure values.

  17. Adsorption Of Water And Benzene Vapour In Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Paulina Taba

    2008-11-01

    Full Text Available Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica: MCM-41, MCM-48 and their modification. MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16 or MCM-41 (C12 respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their modifications were conducted by silylation of MCM-41 (C16 and MCM-48 with trimethylchloro silane (MCM16-TMCS and MCM48-TMCS and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS. Results showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41 (C16 > MCM-48 > MCM-41 (C12. The hydrophobicity increased when MCM-41 and MCM-48 were silylated with TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as selective adsorbents for organic compounds.

  18. Water vapour and ozone profiles in the midlatitude upper troposphere

    Directory of Open Access Journals (Sweden)

    G. Vaughan

    2005-01-01

    Full Text Available We present an investigation of upper tropospheric humidity profiles measured with a standard radiosonde, the Vaisala RS80-A, and a commercial frost-point hygrometer, the Snow White. Modifications to the Snow White, to enable the mirror reflectivity and Peltier cooling current to be monitored during flight, were found to be necessary to determine when the instrument was functioning correctly; a further modification to prevent hydrometeors entering the inlet was also implemented. From 23 combined flights of an ozonesonde, radiosonde and Snow White between September 2001 and July 2002, clear agreement was found between the two humidity sensors, with a mean difference of <2% in relative humidity from 2 to 10km, and 2.2% between 10 and 13km. This agreement required a correction to the radiosonde humidity, as described by Miloshevich et al. (2001. Using this result, the dataset of 324 ozonesonde/RS80-A profiles measured from Aberystwyth between 1991 and 2002 was examined to derive statistics for the distribution of water vapour and ozone. Supersaturation with respect to ice was frequently seen at the higher levels - 24% of the time in winter between 8 and 10km. The fairly uniform distribution of relative humidity persisted to 120% in winter, but decreased rapidly above 100% in summer.

  19. Poly(methyl methacrylate) films for organic vapour sensing

    CERN Document Server

    Capan, R; Hassan, A K; Tanrisever, T

    2003-01-01

    Optical constants and fabrication parameters are investigated using surface plasmon resonance (SPR) studies on spun films of poly(methyl methacrylate) (PMMA) derivatives in contact with two different dielectric media. A value of 1.503 for the refractive index of PMMA films produced from a solution having concentration of 1 mg ml sup - sup 1 at the speed of 3000 rpm is in close agreement with the data obtained from ellipsometric measurements. The film thickness shows a power-law dependence on the spin speed but the thickness increases almost linearly with the concentration of the spreading solution. These results are in good agreement with the hydrodynamic theory for a low-viscosity and highly volatile liquid. On the basis of SPR measurements under dynamic conditions, room temperature response of PMMA films to benzene vapours is found to be fast, highly sensitive and reversible. The sensitivity of detection of toluene, ethyl benzene and m-xylene is much smaller than that of benzene.

  20. Protection of historical lead against acetic acid vapour

    Directory of Open Access Journals (Sweden)

    Pecenová Z.

    2016-03-01

    Full Text Available Historical lead artefacts (small figurines, appliques, bull (metal seal can be stored in depository and archives in inconvenient storage conditions. The wooden show-case or paper packagings release volatile organic compound to the air during their degradation. These acids, mainly acetic acid are very corrosive for lead. The thin layer of corrosion products which slows atmospheric corrosion is formed on lead surface in atmospheric condition. In presence of acetic acid vapour the voluminous corrosion products are formed and fall off the surface. These corrosion products do not have any protection ability. The lead could be protected against acid environment by layer of “metal soup” which is formed on surface after immersion in solution of salt of carboxylic acid for 24 hours. The solutions of acids (with vary long of carbon chain and their salts are examined. Longer carbon chain provides better efficiency convers layer. The disadvantages are low solubility of carboxylic acids in water and bad abrasion resistance of formed layer.

  1. The characteristics of a vapour bubble moving in a non-uniform flow field

    Science.gov (United States)

    Hangen, Ni; Jianbo, Huang

    1986-08-01

    The present paper describes the dynamic process of a vapour bubble moving in a non-uniform flow field. The coupling between the bubble moving as a whole and the deformation of the bubble surface is considered. The effect of the pressure gradient on the bubble movement is analysed. For a given flow field the numerical calculation is carried out until the vapour bubble is split by a micro-jet.

  2. Nano-Scale Structure Investigation of Vapour Deposited AlCrSiN Coating Using Transmission Electron Microscope Techniques

    Directory of Open Access Journals (Sweden)

    Lukaszkowicz K.

    2016-06-01

    Full Text Available The investigations concerned the structural analysis of the AlCrSiN coating deposited by arc Physical Vapour Deposition method on the X40CrMoV5-1 hot work tool steel substrate. The deposition process was carried out on a device equipped with a technique of lateral, rotating cathodes. The nano/microstructure, phase identification and chemical state of the coating were analysed by high-resolution transmission electron microscopy. It was found that the investigated coatings have nanostructured nature consisting of fine crystallites. The fractographic tests were made using the scanning electron microscope and allow to state, that the coating was deposited uniformly and tightly adhere to the substrate material. In the work is presented the nature of a transition zone between the produced AlCrSiN coating and substrate material.

  3. First retrieval of global water vapour column amounts from SCIAMACHY measurements

    Directory of Open Access Journals (Sweden)

    S. Noël

    2004-01-01

    Full Text Available Global water vapour column amounts have been derived for the first time from measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY on the European environmental satellite ENVISAT. For this purpose, two different existing retrieval algorithms have been adapted, namely the Air Mass Corrected Differential Absorption Spectroscopy (AMC-DOAS which was originally designed for GOME and the Weighting Function Modified Differential Absorption Spectroscopy (WFM-DOAS which was mainly designed for the retrieval of CH4, CO2 and CO from SCIAMACHY near-infrared spectra. Here, both methods have been applied to SCIAMACHY's nadir measurements in the near-visible spectral region around 700 nm. Taking into account a systematic offset of 10%, the results of these two methods agree within a scatter of about ±0.5 g/cm2 with corresponding SSM/I and ECMWF water vapour data. This deviation includes contributions from the temporal and spatial variability of water vapour. In fact, the mean deviation between the SCIAMACHY and the correlative data sets is much smaller: the SCIAMACHY total water vapour columns are typically about 0.15 g/cm2 lower than the SSM/I values and less than 0.1 g/cm2 lower than corresponding ECMWF data. The SCIAMACHY water vapour results agree well with correlative data not only over ocean but also over land, thus showing the capability of SCIAMACHY to derive water vapour concentrations on the global scale.

  4. Performance investigation of vapour recompressed batch distillation for separating ternary wide boiling constituents

    Directory of Open Access Journals (Sweden)

    Rohith R Nair

    2017-12-01

    Full Text Available The vapour recompression scheme (VRC has been very effective in continuous distillation for energy intensification. The applicability of this scheme for the separation of multicomponent wide boiling constituents in batch distillation is a major challenge, because of the unsteady nature of the batch. In this study, the vapour recompression scheme has been implemented for the separation of multicomponent wide boiling constituents in the batch distillation. For the optimal usage of energy from compressed vapours manipulation of top tray vapour or external energy is done. A comparative study of the vapour recompressed batch distillation having a variable speed single compressor (SVRBD and double stage compressor (DVRBD with conventional batch distillation in terms of energy savings and total annualized cost is done. The VRC schemes achieve an energy savings of 50% and 10.03% total annualized cost (TAC for SVRBD and DVRBD achieve 52% energy savings and 12.21% TAC with a payback period of 10 years. Keywords: Batch distillation, Vapour recompression, Wide boiling constituents, Energy saving, Total annualized cost

  5. Immunological disorders in men exposed to metallic mercury vapour. A review.

    Science.gov (United States)

    Moszczyński, P

    1999-02-01

    The awareness of the effects of metallic mercury vapour on the human immune system has increased only in the last decade. The regulatory guidelines relating to testing for immunotoxicity of metals are not standardized so far. A full understanding of the relevance of the tests to man is still incomplete. Immunotoxicity investigation of metals in rodents, with subsequent extrapolation to man, forms the basis of human risk assessment. Human contact with mercury vapour is mainly in chloralkali plants and in factories producing controlling and measuring devices. When the immune system acts as a target of xenobiotic insults, the result can be a decreased resistance to infection, cancers, or immune disregulation that can induce the development of allergy, or autoimmunity (Fig. 1). This article reviews literature data and our studies concerning the immunotoxicity of metallic mercury vapour. A number of data shows that mercury exerts a suppressing effect but another data suggest stimulating effects on the human immune system. The results of immunological monitoring of individuals exposed to mercury vapour were either positive or negative as well as borderline and uncertain as to the influence of mercury vapour on human immune system. The positive data had no influence on the resistance of workers to infections and neoplasms. Skin and mucosa hypersensitivity to metallic mercury is rare. No positive report that mercury vapour could be carcinogenic in man has appeared up to now.

  6. Comparison of tanker drivers' occupational exposures before and after the installation of a vapour recovery system.

    Science.gov (United States)

    Saarinen, L; Hakkola, M; Kangas, J

    2000-12-01

    The purpose of this study was to compare tanker drivers' occupational exposure level before and after the installation of vapour recovery facilities at 14 service stations. Road tanker drivers are exposed when handling volatile petrol liquid in bulk in the distribution chain. The drivers' exposure was studied during the unloading operation as the bulk petrol flowed into underground storage tanks, displacing vapours in the tank space and causing emission to the environment and the drivers' work area. The exposures were measured again when the dual point Stage I vapour recovery systems were installed for recycling vapours. Short-term measurements were carried out in the drivers' breathing zones by drawing polluted air through a charcoal tube during unloading. The samples were analysed in the laboratory by gas chromatography for C3-C11 aliphatic hydrocarbons, tert-butyl methyl ether (MTBE), tert-amyl methyl ether (MTAE), benzene, toluene and xylene. The road tanker loads delivered consisted of oxygenated and reformulated petrol (E95 and E98 brands), which contained on average 13% oxygenates. Before the installation of the vapour recovery system, the geometric mean (GM) concentration of aliphatic hydrocarbons was 65 mg m-3 (range 6-645 mg m-3) in the drivers' breathing zones. After the installation at the same service stations, the corresponding exposure level was 8.3 mg m-3 (range tankers without and with vapour recovery were statistically significant (p < 0.05).

  7. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. S Z Mohamed Shamshuddin. Articles written in Journal of Chemical Sciences. Volume 122 Issue 2 March 2010 pp 193-201 Full Papers. Vapour phase synthesis of salol over solid acids via transesterification · S Z Mohamed Shamshuddin N Nagaraju · More Details Abstract ...

  8. Preparation of highly photocatalytic active CdS/TiO{sub 2} nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: qqhrll@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Key Laboratory of Composite Modified Material of Colleges in Heilongjiang Province, Qiqihar 161006 (China); Wang, Lili [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Hu, Tianyu [College of Environment and Resources, Jilin University, Changchun 130024 (China); Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2014-10-15

    CdS/TiO{sub 2} nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N{sub 2} adsorption–desorption measurements. The results show that the CdS/TiO{sub 2} nanocomposites were composed of anatase TiO{sub 2} and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO{sub 2} (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO{sub 2} nanocomposites. The CdS/TiO{sub 2} (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO{sub 2} nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO{sub 2} nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO{sub 2} changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO{sub 2} was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of

  9. The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

    Energy Technology Data Exchange (ETDEWEB)

    N' Dri Koffi, Ernest; Maetzler, Christian [Bern Univ. (Switzerland). Inst. of Applied Physics; Graham, Edward [Bern Univ. (Switzerland). Inst. of Applied Physics; University of the Highlands and Islands, Stornoway, Scotland (United Kingdom). Lews Castle College

    2013-10-15

    The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the 'Swiss box') to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 x 10{sup 7} kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box 'import' more water vapour than it 'exports', but the amount gained remains only a small fraction (1% to 5%) of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products. (orig.)

  10. The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

    Directory of Open Access Journals (Sweden)

    Ernest N'dri Koffi

    2013-07-01

    Full Text Available The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the “Swiss box” to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 · 107 kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box “import” more water vapour than it “exports”, but the amount gained remains only a small fraction (1% to 5% of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products.

  11. Comparison of the Cytotoxic Potential of Cigarette Smoke and Electronic Cigarette Vapour Extract on Cultured Myocardial Cells

    Directory of Open Access Journals (Sweden)

    Dimitris Tsiapras

    2013-10-01

    Full Text Available Background: Electronic cigarettes (ECs have been marketed as an alternative-to-smoking habit. Besides chemical studies of the content of EC liquids or vapour, little research has been conducted on their in vitro effects. Smoking is an important risk factor for cardiovascular disease and cigarette smoke (CS has well-established cytotoxic effects on myocardial cells. The purpose of this study was to evaluate the cytotoxic potential of the vapour of 20 EC liquid samples and a “base” liquid sample (50% glycerol and 50% propylene glycol, with no nicotine or flavourings on cultured myocardial cells. Included were 4 samples produced by using cured tobacco leaves in order to extract the tobacco flavour. Methods: Cytotoxicity was tested according to the ISO 10993-5 standard. By activating an EC device at 3.7 volts (6.2 watts—all samples, including the “base” liquid and at 4.5 volts (9.2 watts—four randomly selected samples, 200 mg of liquid evaporated and was extracted in 20 mL of culture medium. Cigarette smoke (CS extract from three tobacco cigarettes was produced according to ISO 3308 method (2 s puffs of 35 mL volume, one puff every 60 s. The extracts, undiluted (100% and in four dilutions (50%, 25%, 12.5%, and 6.25%, were applied to myocardial cells (H9c2; percent-viability was measured after 24 h incubation. According to ISO 10993-5, viability of 6.25% (viability: 76.9 ± 2.0% at 6.25%, 38.2 ± 0.5% at 12.5%, 3.1 ± 0.2% at 25%, 5.2 ± 0.8% at 50%, and 3.9 ± 0.2% at 100% extract concentration. Three EC extracts (produced by tobacco leaves were cytotoxic at 100% and 50% extract concentrations (viability range: 2.2%–39.1% and 7.4%–66.9% respectively and one (“Cinnamon-Cookies” flavour was cytotoxic at 100% concentration only (viability: 64.8 ± 2.5%. Inhibitory concentration 50 was >3 times lower in CS extract compared to the worst-performing EC vapour extract. For EC extracts produced by high-voltage and energy, viability was

  12. Comparison of the cytotoxic potential of cigarette smoke and electronic cigarette vapour extract on cultured myocardial cells.

    Science.gov (United States)

    Farsalinos, Konstantinos E; Romagna, Giorgio; Allifranchini, Elena; Ripamonti, Emiliano; Bocchietto, Elena; Todeschi, Stefano; Tsiapras, Dimitris; Kyrzopoulos, Stamatis; Voudris, Vassilis

    2013-10-16

    Electronic cigarettes (ECs) have been marketed as an alternative-to-smoking habit. Besides chemical studies of the content of EC liquids or vapour, little research has been conducted on their in vitro effects. Smoking is an important risk factor for cardiovascular disease and cigarette smoke (CS) has well-established cytotoxic effects on myocardial cells. The purpose of this study was to evaluate the cytotoxic potential of the vapour of 20 EC liquid samples and a "base" liquid sample (50% glycerol and 50% propylene glycol, with no nicotine or flavourings) on cultured myocardial cells. Included were 4 samples produced by using cured tobacco leaves in order to extract the tobacco flavour. Cytotoxicity was tested according to the ISO 10993-5 standard. By activating an EC device at 3.7 volts (6.2 watts-all samples, including the "base" liquid) and at 4.5 volts (9.2 watts-four randomly selected samples), 200 mg of liquid evaporated and was extracted in 20 mL of culture medium. Cigarette smoke (CS) extract from three tobacco cigarettes was produced according to ISO 3308 method (2 s puffs of 35 mL volume, one puff every 60 s). The extracts, undiluted (100%) and in four dilutions (50%, 25%, 12.5%, and 6.25%), were applied to myocardial cells (H9c2); percent-viability was measured after 24 h incubation. According to ISO 10993-5, viability of 6.25% (viability: 76.9 ± 2.0% at 6.25%, 38.2 ± 0.5% at 12.5%, 3.1 ± 0.2% at 25%, 5.2 ± 0.8% at 50%, and 3.9 ± 0.2% at 100% extract concentration). Three EC extracts (produced by tobacco leaves) were cytotoxic at 100% and 50% extract concentrations (viability range: 2.2%-39.1% and 7.4%-66.9% respectively) and one ("Cinnamon-Cookies" flavour) was cytotoxic at 100% concentration only (viability: 64.8 ± 2.5%). Inhibitory concentration 50 was >3 times lower in CS extract compared to the worst-performing EC vapour extract. For EC extracts produced by high-voltage and energy, viability was reduced but no sample was cytotoxic according to

  13. A collisional-radiative model of iron vapour in a thermal arc plasma

    Science.gov (United States)

    Baeva, M.; Uhrlandt, D.; Murphy, A. B.

    2017-06-01

    A collisional-radiative model for the ground state and fifty effective excited levels of atomic iron, and one level for singly-ionized iron, is set up for technological plasmas. Attention is focused on the population of excited states of atomic iron as a result of excitation, de-excitation, ionization, recombination and spontaneous emission. Effective rate coefficients for ionization and recombination, required in non-equilibrium plasma transport models, are also obtained. The collisional-radiative model is applied to a thermal arc plasma. Input parameters for the collisional-radiative model are provided by a magnetohydrodynamic simulation of a gas-metal welding arc, in which local thermodynamic equilibrium is assumed and the treatment of the transport of metal vapour is based on combined diffusion coefficients. The results clearly identify the conditions in the arc, under which the atomic state distribution satisfies the Boltzmann distribution, with an excitation temperature equal to the plasma temperature. These conditions are met in the central part of the arc, even though a local temperature minimum occurs here. This provides assurance that diagnostic methods based on local thermodynamic equilibrium, in particular those of optical emission spectroscopy, are reliable here. In contrast, deviations from the equilibrium atomic-state distribution are obtained in the near-electrode and arc fringe regions. As a consequence, the temperatures determined from the ratio of line intensities and number densities obtained from the emission coefficient in these regions are questionable. In this situation, the collisional-radiative model can be used as a diagnostic tool to assist in the interpretation of spectroscopic measurements.

  14. The millennium water vapour drop in chemistry–climate model simulations

    Directory of Open Access Journals (Sweden)

    S. Brinkop

    2016-07-01

    Full Text Available This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop" and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM EMAC (ECHAM/MESSy Atmospheric Chemistry Model. The model simulations differ with respect to the prescribed sea surface temperatures (SSTs and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer–Dobson circulation (BDC. We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST changes due to a coincidence with a preceding strong El Niño–Southern Oscillation event (1997/1998 followed by a strong La Niña event (1999/2000 and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO in 2000. Correct (observed SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics

  15. WAVE-E: The WAter Vapour European-Explorer Mission

    Science.gov (United States)

    Jimenez-LLuva, David; Deiml, Michael; Pavesi, Sara

    2017-04-01

    In the last decade, stratosphere-troposphere coupling processes in the Upper Troposphere Lower Stratosphere (UTLS) have been increasingly recognized to severely impact surface climate and high-impact weather phenomena. Weakened stratospheric circumpolar jets have been linked to worldwide extreme temperature and high-precipitation events, while anomalously strong stratospheric jets can lead to an increase in surface winds and tropical cyclone intensity. Moreover, stratospheric water vapor has been identified as an important forcing for global decadal surface climate change. In the past years, operational weather forecast and climate models have adapted a high vertical resolution in the UTLS region in order to capture the dynamical processes occurring in this highly stratified region. However, there is an evident lack of available measurements in the UTLS region to consistently support these models and further improve process understanding. Consequently, both the IPCC fifth assessment report and the ESA-GEWEX report 'Earth Observation and Water Cycle Science Priorities' have identified an urgent need for long-term observations and improved process understanding in the UTLS region. To close this gap, the authors propose the 'WAter Vapour European - Explorer' (WAVE-E) space mission, whose primary goal is to monitor water vapor in the UTLS at 1 km vertical, 25 km horizontal and sub-daily temporal resolution. WAVE-E consists of three quasi-identical small ( 500 kg) satellites (WAVE-E 1-3) in a constellation of Sun-Synchronous Low Earth Orbits, each carrying a limb sounding and cross-track scanning mid-infrared passive spectrometer (824 cm-1 to 829 cm-1). The core of the instruments builds a monolithic, field-widened type of Michelson interferometer without any moving parts, rendering it rigid and fault tolerant. Synergistic use of WAVE-E and MetOp-NG operational satellites is identified, such that a data fusion algorithm could provide water vapour profiles from the

  16. Growth of thick La{sub 2}Zr{sub 2}O{sub 7} buffer layers for coated conductors by polymer-assisted chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin, E-mail: xzhang@my.swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Yong, E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Xia, Yudong [State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Guo, Chunsheng [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Zhang, Yong [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, Han [Department of Physics, Peking University, Beijing 100871 (China)

    2015-06-15

    Highlights: • We develops a low-cost and high-efficient technology of fabricating LZO buffer layers. • Sufficient thickness LZO buffer layers have been obtained on NiW (2 0 0) alloy substrate. • Highly biaxially textured YBCO thin film has been deposited on LZO/NiW. - Abstract: La{sub 2}Zr{sub 2}O{sub 7} (LZO) epitaxial films have been deposited on LaAlO{sub 3} (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa{sub 2}Cu{sub 3}O{sub 7−x} (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm{sup 2} at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors.

  17. SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

    DEFF Research Database (Denmark)

    Boy, M.; Sogachev, Andrey; Lauros, J.

    2011-01-01

    Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions......, transport and chemistry in the ABL in and above a vegetation canopy using tower measurements from the SMEAR II at Hyytiälä, Finland and available soundings data from neighbouring meteorological stations. Using the sounding data for upper boundary condition and nudging the model to tower measurements...

  18. SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

    DEFF Research Database (Denmark)

    Boy, M.; Sogachev, Andrey; Lauros, J.

    2010-01-01

    Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions......, transport and chemistry in the ABL in and above a vegetation canopy using tower measurements from the SMEAR II at Hyytiälä, Finland and available soundings data from neighbouring meteorological stations. Using the sounding data for upper boundary condition and nudging the model to tower measurements...

  19. Continuous measurements of isotopic composition of water vapour on the East Antarctic Plateau

    Directory of Open Access Journals (Sweden)

    M. Casado

    2016-07-01

    Full Text Available Water stable isotopes in central Antarctic ice cores are critical to quantify past temperature changes. Accurate temperature reconstructions require one to understand the processes controlling surface snow isotopic composition. Isotopic fractionation processes occurring in the atmosphere and controlling snowfall isotopic composition are well understood theoretically and implemented in atmospheric models. However, post-deposition processes are poorly documented and understood. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum between surface water vapour, precipitation, surface snow and buried snow. Here, we target the isotopic composition of water vapour at Concordia Station, where the oldest EPICA Dome C ice cores have been retrieved. While snowfall and surface snow sampling is routinely performed, accurate measurements of surface water vapour are challenging in such cold and dry conditions. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces. Two infrared spectrometers have been deployed at Concordia, allowing continuous, in situ measurements for 1 month in December 2014–January 2015. Comparison of the results from infrared spectroscopy with laboratory measurements of discrete samples trapped using cryogenic sampling validates the relevance of the method to measure isotopic composition in dry conditions. We observe very large diurnal cycles in isotopic composition well correlated with temperature diurnal cycles. Identification of different behaviours of isotopic composition in the water vapour associated with turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction. Even if the vapour isotopic composition seems to be, at least part of the time, at equilibrium with the local snow, the slope of δD against δ18O prevents us from identifying

  20. Vapour pressures, aqueous solubilities, Henry's law constants, partition coefficients between gas/water (Kgw), n-octanol/water (Kow) and gas/n-octanol (Kgo) of 106 polychlorinated diphenyl ethers (PCDE)

    Science.gov (United States)

    Kurz; Ballschmiter

    1999-02-01

    Modelling the environmental fate of persistent organic pollutants like polychlorinated diphenyl ethers (PCDE) requires the knowledge of a number of fundamental physico-chemical properties of these compounds. We report here the physico-chemical properties of 106 PCDEs, which are over 50% of all possible congeners. Vapour pressures P(OL), water solubilities S(H2O), and n-octanol/water partition coefficients K(OW) were determined with chromatographic methods. With these experimental data the Henry's law constants H, gas/water K(GW) and gas/n-octanol K(GO) partition coefficients were calculated. Vapour pressures and water solubilities and n-octanol/water partition coefficients of the PCDEs are close to those of similar groups of organochlorine compounds like polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs). A similar environmental fate can be predicted and was partially already been observed.

  1. Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells

    OpenAIRE

    Raphaela Putzhammer; Christian Doppler; Thomas Jakschitz; Katharina Heinz; Juliane Förste; Katarina Danzl; Barbara Messner; David Bernhard

    2016-01-01

    The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothe...

  2. The Droplets Condensate Centering in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

    Science.gov (United States)

    Seryakov, A. V.; Shakshin, S. L.; Alekseev, A. P.

    2017-11-01

    The results of experimental studies of the process of condensate microdroplets centering contained in the moving moist vapour in the vapour channel of short heat pipes (HPs) for large thermal loads are presented. A vapour channel formed by capillary-porous insert in the form of the inner Laval-liked nozzle along the entire length of the HP. In the upper cover forming a condensation surface in the HP, on the diametrical line are installed capacitive sensors, forming three capacitors located at different distances from the longitudinal axis of the vapour channel. With increasing heat load and the boil beginning in the evaporator a large amount of moist vapour in the vapour channel of HP occur the pressure pulsation with frequency of 400-500 Hz and amplitude up to 1·104Pa. These pulsations affect the moving of the inertial droplets subsystem of the vapour and due to the heterogeneity of the velocity profile around the particle flow in the vapour channel at the diameter of microdroplets occurs transverse force, called the Saffman force and shear microdroplets to the center of vapour channel. Using installed in the top cover capacitors we can record the radial displacement of the condensable microdroplets.

  3. Efficacy of scalp hair decontamination following exposure to vapours of sulphur mustard simulants 2-chloroethyl ethyl sulphide and methyl salicylate.

    Science.gov (United States)

    Spiandore, Marie; Piram, Anne; Lacoste, Alexandre; Prevost, Philippe; Maloni, Pascal; Torre, Franck; Asia, Laurence; Josse, Denis; Doumenq, Pierre

    2017-04-01

    Chemical warfare agents are an actual threat and victims' decontamination is a main concern when mass exposure occurs. Skin decontamination with current protocols has been widely documented, as well as surface decontamination. However, considering hair ability to trap chemicals in vapour phase, we investigated hair decontamination after exposure to sulphur mustard simulants methyl salicylate and 2-chloroethyl ethyl sulphide. Four decontamination protocols were tested on hair, combining showering and emergency decontamination (use of Fuller's earth or Reactive Skin Decontamination Lotion RSDL ® ). Both simulants were recovered from hair after treatment, but contents were significantly reduced (42-85% content allowance). Showering alone was the least efficient protocol. Concerning 2-chloroethyl ethyl sulphide, protocols did not display significant differences in decontamination efficacy. For MeS, use of emergency decontaminants significantly increased showering efficacy (10-20% rise), underlining their usefulness before thorough decontamination. Our results highlighted the need to extensively decontaminate hair after chemical exposure. Residual amounts after decontamination are challenging, as their release from hair could lead to health issues. Copyright © 2016. Published by Elsevier B.V.

  4. Strain and Structure Heterogeneity in MoS2 Atomic Layers Grown by Chemical Vapour Deposition

    Science.gov (United States)

    2014-11-18

    polymer substrates to MoS2 by three-dimensional finite element analysis. Furthermore, our work demonstrates that photoluminescence mapping can be...hour per response, including the time for reviewing instructions, ~earchi ng existing data sources, gathering and maintaining the data needed, and...completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of

  5. Hot-wire chemical vapour deposition at low substrate temperatures for optoelectronic applications

    NARCIS (Netherlands)

    Bakker, R.|info:eu-repo/dai/nl/304826677

    2010-01-01

    The need for large quantities of rapidly and cheaply produced electronic devices has increased rapidly over the past decades. The transistors and diodes that are used to build these devices are predominantly made of crystalline silicon. Since crystalline silicon is very expensive to produce on a

  6. The Effect of C02, Sweat, Chemical Vapours and Air on Simulium ...

    African Journals Online (AJOL)

    Studies on the response of the blackfly Simulium ornatum s.l (Diptera Simuliidae) to carbon dioxide (CO2), acetone, 1-octen-3-ol and air was conducted in the laboratory using a Y-tube olfactometer. The blackflies were found to exhibit a high degree of activity in the olfactometer and responded to the various odours.

  7. Laser approaches for deposition of carbon nitride films - chemical vapour deposition and ablation

    Czech Academy of Sciences Publication Activity Database

    Popov, C.; Jelínek, Miroslav; Ivanov, B.; Tomov, R. I.; Kulisch, W.

    1999-01-01

    Roč. 8, - (1999), s. 577-581 ISSN 0925-9635 R&D Projects: GA ČR GA202/93/0464 Institutional research plan: CEZ:AV0Z1010914 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.924, year: 1999

  8. Direct chemical vapour deposited grapheme synthesis on silicon oxide by controlled copper dewettting

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

    2015-01-01

    In this paper we present a novel method for direct uniform graphene synthesis onto silicon oxide in a controlled manner. On a grooved silicon oxide wafer is copper deposited under a slight angle and subsequently the substrate is treated by a typical graphene synthesis process. During this process

  9. LOW-TEMPERATURE GRAPHENE GROWTH ON COPPER FOIL CATALYST BY CHEMICAL VAPOUR DEPOSITION (CVD METHOD

    Directory of Open Access Journals (Sweden)

    Kasman Kasman

    2016-08-01

    Full Text Available Graphene growth at low temperatures (below 500 oC on copper catalyst by CVD method was studied. The goal of this study is to determine a minimum growth temperature for growing graphene with high quality. In this study, the catalyst used for growing graphene was copper foil (Sigma-Aldrich, code: 1001328641, 25 µm in thickness, 99.98% trace metals basis, cut into 2x1 cm2 in size  annealed at 900 oC , while the precursor used was poly(methyl methacrylate (PMMA heated at 140 oC. In graphene growth, two different growth temperatures of 350 oC and 450 oC were varied. The graphene films grown on copper foil catalyst were characterised using SEM and Raman spectroscopy. While, the films transferred onto quartz/glass/grid substrates were characterised by using SEM, Raman spectroscopy, UV-vis spectroscopy, four point probe and TEM. Results of this study showed that the 450 oC-grown samples produce a better quality graphene film compared to the 350 oC-grown samples. In other words, the minimum temperature of graphene growth is at least 450 oC for a Cu foil, since this temperature has to be sufficiently high to activate carbon diffusion and rearrangement on the catalyst surface..

  10. Applicability of chemical vapour polishing of additive manufactured parts to meet production-quality

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    The Fused Deposition Modelling (FDM) method is the most rapidly growing Additive Manufacturing (AM) method[1]. FDM employs a 2.5D deposition scheme which induce a step-ladder shaped surface definition [2], with seams of the individual layers clearly visible[3]. This paper investigate to which ext...

  11. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.

    2005-01-01

    of deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects...

  12. SiC fibre by chemical vapour deposition on tungsten filament

    Indian Academy of Sciences (India)

    Unknown

    Jones 1975). The next generation aircraft engines need lighter high performance structural materials with high temperature capabilities (Sorensen 1993). ... 1997). Ti–6Al–4V/sigma-1240(SiC) composites exhibit a high elastic stiffness (axial elastic modulus above 200 GPa) and fracture strength (UTS ≈ 1⋅8 GPa) and a ...

  13. Chemical vapour deposition of optical coatings onto small scale complex optical components

    Science.gov (United States)

    Hitchman, M. L.; Gibson, D. R.; Manookian, W.; Waddell, E. M.

    2005-09-01

    In this paper we describe how optical coatings can be deposited uniformly with a high precision and reproducibility on 3-dimensional substrates, such as spherical lenses, by CVD. We present results that will highlight some specific advantages of CVD over the traditionally used methods of e-beam evaporation and magnetron sputtering and we will show that CVD has tremendous potential for enhancing the quality of optical coatings and for making cost savings.

  14. Control and Characterization of Individual Grains and Grain Boundaries in Graphene Grown by Chemical Vapour Deposition

    Science.gov (United States)

    2011-06-01

    field (B). Figure 5c presents low temperature (4.3 K) magnetoresistance (Rxx(B)) measurements across the grain boundary compared to Rxx(B) measured within...voltage leads labelled in the legend. c, Four-terminal magnetoresistance (Rxx) measured at 4.3 K within each graphene grain and across the grain boundary...graphene nanoribbons. Nature 444, 347–349 (2006). 37. Huang, M. Y. et al. Phonon softening and crystallographic orientation of strained graphene studied by

  15. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics

    KAUST Repository

    Qi, Junjie

    2015-06-25

    High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical–electronic nanodevices.

  16. Applicability of chemical vapour polishing of additive manufactured parts to meet production-quality

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    The Fused Deposition Modelling (FDM) method is the most rapidly growing Additive Manufacturing (AM) method[1]. FDM employs a 2.5D deposition scheme which induce a step-ladder shaped surface definition [2], with seams of the individual layers clearly visible[3]. This paper investigate to which...... of FDM manufactured parts can be taken from their current quality into the precision engineering domain....

  17. SiC fibre by chemical vapour deposition on tungsten filament

    Indian Academy of Sciences (India)

    A CVD system for the production of continuous SiC fibre was set up. The process of SiC coating on 19 m diameter tungsten substrate was studied. Methyl trichloro silane (CH3SiCl3) and hydrogen reactants were used. Effect of substrate temperature (1300–1500°C) and concentration of reactants on the formation of SiC ...

  18. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

  19. Effect of Liquid/Vapour Maldistribution on the Performance of Plate Heat Exchanger Evaporators

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Kærn, Martin Ryhl; Ommen, Torben Schmidt

    2015-01-01

    Plate heat exchangers are often applied as evaporators in industrial refrigeration and heat pump systems. In the design and modelling of such heat exchangers the flow and liquid/vapour distribution is often assumed to be ideal. However, maldistribution may occur and will cause each channel...... to behave differently due to the variation of the mass flux and vapour quality. To evaluate the effect of maldistribution on the performance of plate heat exchangers, a numerical model is developed in which the mass, momentum and energy balances are applied individually to each channel, including suitable...... correlations for heat transfer and pressure drop. The flow distribution on both the refrigerant and secondary side is determined based on equal pressure drop while the liquid/vapour distribution is imposed to the model. Results show that maldistribution may cause up to a 25 % reduction of the overall heat...

  20. Prediction of clothing thermal insulation and moisture vapour resistance of the clothed body walking in wind.

    Science.gov (United States)

    Qian, Xiaoming; Fan, Jintu

    2006-11-01

    Clothing thermal insulation and moisture vapour resistance are the two most important parameters in thermal environmental engineering, functional clothing design and end use of clothing ensembles. In this study, clothing thermal insulation and moisture vapour resistance of various types of clothing ensembles were measured using the walking-able sweating manikin, Walter, under various environmental conditions and walking speeds. Based on an extensive experimental investigation and an improved understanding of the effects of body activities and environmental conditions, a simple but effective direct regression model has been established, for predicting the clothing thermal insulation and moisture vapour resistance under wind and walking motion, from those when the manikin was standing in still air. The model has been validated by using experimental data reported in the previous literature. It has shown that the new models have advantages and provide very accurate prediction.

  1. Kinetic model of water vapour adsorption by gluten-free starch

    Science.gov (United States)

    Ocieczek, Aneta; Kostek, Robert; Ruszkowska, Millena

    2015-01-01

    This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any timepoint of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.

  2. Measurement of water vapour transport through a porous non-hygroscopic material in a temperature gradient

    DEFF Research Database (Denmark)

    Hansen, Thor; Padfield, Tim; Hansen, Kurt Kielsgaard

    2014-01-01

    This was an experiment to identify the driving potential for water vapour diffusion through porous materials in a temperature gradient. The specimen of mineral fibre insulation was placed between a space with controlled temperature and relative humidity and a space with a controlled, higher...... temperature, and a measured but not controlled relative humidity (RH). This assembly was allowed to reach equilibrium with no vapour movement between the spaces, as tested by a constant RH on each side and by zero flux of water vapour measured in the cold side chamber. The RH and temperature values were...... be tested experimentally in this way, but it is reasonable to assume that concentration is the driving potential. The close equality of the concentrations makes it unnecessary to invoke temperature difference as a third possible potential for driving diffusion....

  3. Distribution of tritium in water vapour and precipitation around Wolsung nuclear power plant.

    Science.gov (United States)

    Chae, Jung-Seok; Lee, Sang-Kuk; Kim, Yongjae; Lee, Jung-Min; Cho, Heung-Joon; Cho, Yong-Woo; Yun, Ju-Yong

    2011-07-01

    The distribution of tritium in water vapour and precipitation with discharge of tritiated water vapour and meteorological factors was studied around the Wolsung nuclear power plant (NPP) site during the period 2004-2008. The tritium concentrations in atmospheric water vapour and precipitation had a temporal variation with relatively high values in the early summer. Spatial distribution of tritium concentrations was affected by various factors such as distance from the NPP site, wind direction, tritium discharge into the atmosphere and atmospheric dispersion factor. The annual mean concentrations of atmospheric HTO and precipitation were correlated with the amount of gaseous tritium released from the Wolsung NPP. The tritium concentrations in precipitation decrease exponentially with an increase of the distance from the Wolsung NPP site.

  4. Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells.

    Science.gov (United States)

    Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; Förste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

    2016-01-01

    The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

  5. Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells.

    Directory of Open Access Journals (Sweden)

    Raphaela Putzhammer

    Full Text Available The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

  6. Upper tropospheric water vapour variability at high latitudes – Part 1: Influence of the annular modes

    Directory of Open Access Journals (Sweden)

    C. E. Sioris

    2016-03-01

    Full Text Available Seasonal and monthly zonal medians of water vapour in the upper troposphere and lower stratosphere (UTLS are calculated for both Atmospheric Chemistry Experiment (ACE instruments for the northern and southern high-latitude regions (60–90° N and 60–90° S. Chosen for the purpose of observing high-latitude processes, the ACE orbit provides sampling of both regions in 8 of 12 months of the year, with coverage in all seasons. The ACE water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation and the Fourier Transform Spectrometer (ACE-FTS are currently the only satellite instruments that can probe from the lower stratosphere down to the mid-troposphere to study the vertical profile of the response of UTLS water vapour to the annular modes. The Arctic oscillation (AO, also known as the northern annular mode (NAM, explains 64 % (r = −0.80 of the monthly variability in water vapour at northern high latitudes observed by ACE-MAESTRO between 5 and 7 km using only winter months (January to March, 2004–2013. Using a seasonal time step and all seasons, 45 % of the variability is explained by the AO at 6.5 ± 0.5 km, similar to the 46 % value obtained for southern high latitudes at 7.5 ± 0.5 km explained by the Antarctic oscillation or southern annular mode (SAM. A large negative AO event in March 2013 produced the largest relative water vapour anomaly at 5.5 km (+70 % over the ACE record. A similarly large event in the 2010 boreal winter, which was the largest negative AO event in the record (1950–2015, led to > 50 % increases in water vapour observed by MAESTRO and ACE-FTS at 7.5 km.

  7. WATER VAPOUR PERMEABILITY PROPERTIES OF CELLULAR WOOD MATERIAL AND CONDENSATION RISK OF COMPOSITE PANEL WALLS

    Directory of Open Access Journals (Sweden)

    Janis IEJAVS

    2016-09-01

    Full Text Available Invention of light weight cellular wood material (CWM with a trade mark of Dendrolight is one of innovations in wood industry of the last decade. The aim of the research was to define the water vapour permeability properties of CWM and to analyse the condensation risk of various wall envelopes where solid wood cellular material is used. To determine the water vapour permeability of CWM, test samples were produced in the factory using routine production technology and tested according to the standard EN 12086:2014. Water vapour permeability factor (μ and other properties of six different configurations of CWM samples were determined. Using the experimental data the indicative influence of geometrical parameters such as lamella thickness, number of lamellas and material direction were investigated and evaluated. To study the condensation risk within the wall envelope containing CWM calculation method given in LVS EN ISO 13788:2012 was used. To ease the calculation process previously developed JavaScript calculation software that had only capability to calculate thermal transmittance was extended so that condensation risk in multi-layer composite walls can be analysed. Water vapour permeability factor in CWM is highly direction dependant. If parallel and perpendicular direction of CWM is compared the value of water vapour permeability factor can differentiate more than two times. Another significant factor for condensation risk analysis is overall thickness of CWM since it directly influences the equivalent air layer thickness. The influence of other factors such as lamella thickness, or groove depth is minor when water vapour permeability properties are compared. From the analysis of CWM performance in building envelope it can be concluded that uninsulated CWM panels used during winter months will pose the risk of condensation damage to structure, but the risk can be reduced or prevented if insulation layer is applied to the CWM panel wall

  8. Intercomparison of atmospheric water vapour measurements at a Canadian High Arctic site

    Science.gov (United States)

    Weaver, Dan; Strong, Kimberly; Schneider, Matthias; Rowe, Penny M.; Sioris, Chris; Walker, Kaley A.; Mariani, Zen; Uttal, Taneil; McElroy, C. Thomas; Vömel, Holger; Spassiani, Alessio; Drummond, James R.

    2017-08-01

    Water vapour is a critical component of the Earth system. Techniques to acquire and improve measurements of atmospheric water vapour and its isotopes are under active development. This work presents a detailed intercomparison of water vapour total column measurements taken between 2006 and 2014 at a Canadian High Arctic research site (Eureka, Nunavut). Instruments include radiosondes, sun photometers, a microwave radiometer, and emission and solar absorption Fourier transform infrared (FTIR) spectrometers. Close agreement is observed between all combination of datasets, with mean differences ≤ 1.0 kg m-2 and correlation coefficients ≥ 0.98. The one exception in the observed high correlation is the comparison between the microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92.A variety of biases affecting Eureka instruments are revealed and discussed. A subset of Eureka radiosonde measurements was processed by the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) for this study. Comparisons reveal a small dry bias in the standard radiosonde measurement water vapour total columns of approximately 4 %. A recently produced solar absorption FTIR spectrometer dataset resulting from the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) retrieval technique is shown to offer accurate measurements of water vapour total columns (e.g. average agreement within -5.2 % of GRUAN and -6.5 % of a co-located emission FTIR spectrometer). However, comparisons show a small wet bias of approximately 6 % at the high-latitude Eureka site. In addition, a new dataset derived from Atmospheric Emitted Radiance Interferometer (AERI) measurements is shown to provide accurate water vapour measurements (e.g. average agreement was within 4 % of GRUAN), which usefully enables measurements to be taken during day and night (especially valuable during polar night).

  9. Onsager heat of transport at the n-octane liquid vapour interface: Effects of altering the size of the vapour-gap and of adding helium

    Science.gov (United States)

    Phillips, Leon F.

    2008-06-01

    Values of the Onsager heat of transport Q∗ measured at the n-octane liquid-vapour interface are consistent with the results of molecular dynamics calculations by Simon et al. [J.-M. Simon, S. Kjelstrup, D. Bedeaux, B. Hafskjold, J. Phys. Chem. B 108 (2004) 7186.] The measured value of Q∗ is independent of gas pressure but is affected by variations in the size of the vapour gap over which the temperature gradient is applied. Measurements with added helium indicate that Q∗ is negative for helium at the surface of n-octane, even though the enthalpy of solution is positive. The helium results can be understood on the basis of an existing model.

  10. The Gibbs-Thomson formula at small island sizes - corrections for high vapour densities

    OpenAIRE

    Krishnamachari, Badrinarayan; McLean, James; Cooper, Barbara; Sethna, James

    1996-01-01

    In this paper we report simulation studies of equilibrium features, namely circular islands on model surfaces, using Monte-Carlo methods. In particular, we are interested in studying the relationship between the density of vapour around a curved island and its curvature-the Gibbs-Thomson formula. Numerical simulations of a lattice gas model, performed for various sizes of islands, don't fit very well to the Gibbs-Thomson formula. We show how corrections to this form arise at high vapour densi...

  11. Thermal diffusion of water vapour in porous materials: fact or fiction?

    DEFF Research Database (Denmark)

    Janssen, Hans

    2011-01-01

    The reliable evaluation of moisture transfer in porous materials is essential in many engineering applications, among which building science. One key aspect is a correct description of moisture flow phenomena and their transport potentials. While different issues can be debated in that respect...... its negligible magnitude. It can in conclusion be stated that thermal diffusion is of no importance for building science applications, leaving vapour pressure as the sole significant transport potential for the diffusion of water vapour in porous materials. (C) 2010 Elsevier Ltd. All rights reserved....

  12. Spatio-Temporal Estimation of Integrated Water Vapour Over the Malaysian Peninsula during Monsoon Season

    Science.gov (United States)

    Salihin, S.; Musa, T. A.; Radzi, Z. Mohd

    2017-10-01

    This paper provides the precise information on spatial-temporal distribution of water vapour that was retrieved from Zenith Path Delay (ZPD) which was estimated by Global Positioning System (GPS) processing over the Malaysian Peninsular. A time series analysis of these ZPD and Integrated Water Vapor (IWV) values was done to capture the characteristic on their seasonal variation during monsoon seasons. This study was found that the pattern and distribution of atmospheric water vapour over Malaysian Peninsular in whole four years periods were influenced by two inter-monsoon and two monsoon seasons which are First Inter-monsoon, Second Inter-monsoon, Southwest monsoon and Northeast monsoon.

  13. Measurements of the levels of organic solvent vapours by personal air samplers and the levels of urinary metabolites of workers. Part 2. Toluene vapour in a shipbuilding yard (author's transl).

    Science.gov (United States)

    Kira, S

    1977-05-01

    Personal air samplers were applied to shipyard's painters putting on gas masks during the spraying work, and the levels of toluene vapour surrounding the workers were measured. On the other hand, levels of urinary hippuric acid (metabolites of toluene) of the workers were measured, and the levels of toluene vapour inhaled were calculated from the levels of urinary hippuric acid. Then the actual removing-efficiencies of toluene vapours by the use of gas masks were estimated from these two levels (i.e., toluene vapours exposed and inhaled). The values of removing-efficiencies were found to be 65.9-98.1%. The concentrations of hippuric and methylhippuric acids in the urine of workers exposed to toluene and xylene for 3 hours, collected just after the exposure, are valuable indices of these organic solvent vapours inhaled. A minute amount of urinary methylhippuric acid can be determined by means of gas chromatography.

  14. The chemical composition and band gap of amorphous Si:C:N:H layers

    Energy Technology Data Exchange (ETDEWEB)

    Swatowska, Barbara, E-mail: swatow@agh.edu.pl [AGH University of Science and Technology, Department of Electronics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Kluska, Stanislawa; Jurzecka-Szymacha, Maria [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Stapinski, Tomasz [AGH University of Science and Technology, Department of Electronics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Tkacz-Smiech, Katarzyna [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Av. 30, 30-059 Krakow (Poland)

    2016-05-15

    Highlights: • Six type of amorphous hydrogenated films were obtained and analysed. • Investigated chemical bondings strongly influenced energy gap values. • Analysed layers could be applied as semiconductors and also as dielectrics. - Abstract: In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H layers of various content of silicon, carbon and nitrogen, and their band gap. The series of amorphous Si:C:N:H layers were obtained by plasma assisted chemical vapour deposition method in which plasma was generated by RF (13.56 MHz, 300 W) and MW (2.45 GHz, 2 kW) onto monocrystalline silicon Si(001) and borosilicate glass. Structural studies were based on FTIR transmission spectrum registered within wavenumbers 400–4000 cm{sup −1}. The presence of Si−C, Si−N, C−N, C=N, C=C, C≡N, Si−H and C−H bonds was shown. The values band gap of the layers have been determined from spectrophotometric and ellipsometric measurements. The respective values are contained in the range between 1.64 eV – characteristic for typical semiconductor and 4.21 eV – for good dielectric, depending on the chemical composition and atomic structure of the layers.

  15. Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing.

    Science.gov (United States)

    Creemers, E; Nijs, M; Vanheusden, E; Ombelet, W

    2011-12-01

    Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory. © 2011 Blackwell Verlag GmbH.

  16. The first regular measurements of ozone, carbon monoxide and water vapour in the Pacific UTLS by IAGOS

    Directory of Open Access Journals (Sweden)

    Hannah Clark

    2015-08-01

    Full Text Available We present the features seen in the first 2 months (July and August 2012 of data collected over the Pacific by IAGOS (In-service Aircraft for a Global Observing System-equipped aircraft. IAGOS is the continuation and development of the well-known MOZAIC (Measurement of Ozone and Water Vapour on Airbus in-service Aircraft project where scientific instruments were carried on commercially operated A340 aircraft to make measurements of chemical species in the atmosphere. Here, we show data from an aircraft operated by China Airlines on routes from Taipei to Vancouver, which provided the first trans-Pacific measurements by an IAGOS-equipped aircraft. We describe the chemical composition of the extratropical upper troposphere/lower stratosphere (Ex-UTLS across the Pacific basin in the Northern Hemisphere. The observed concentrations of ozone span a range from 18 to 500 ppbv indicating sources in the marine boundary layer and lowermost stratosphere, respectively. Concentrations of carbon monoxide (CO greater than 400 ppbv are observed in the Ex-UTLS suggesting that plumes of pollution have been exported from the continent. These low concentrations of ozone and high concentrations of CO were rarely recorded in 8 yr of MOZAIC observations over the Atlantic.

  17. A review on the recent development of solar absorption and vapour compression based hybrid air conditioning with low temperature storage

    Directory of Open Access Journals (Sweden)

    Noor D. N.

    2016-01-01

    Full Text Available Conventional air conditioners or vapour compression systems are main contributors to energy consumption in modern buildings. There are common environmental issues emanating from vapour compression system such as greenhouse gas emission and heat wastage. These problems can be reduced by adaptation of solar energy components to vapour compression system. However, intermittence input of daily solar radiation was the main issue of solar energy system. This paper presents the recent studies on hybrid air conditioning system. In addition, the basic vapour compression system and components involved in the solar air conditioning system are discussed. Introduction of low temperature storage can be an interactive solution and improved economically which portray different modes of operating strategies. Yet, very few studies have examined on optimal operating strategies of the hybrid system. Finally, the findings of this review will help suggest optimization of solar absorption and vapour compression based hybrid air conditioning system for future work while considering both economic and environmental factors.

  18. Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water

    KAUST Repository

    Vakarelski, Ivan Uriev

    2014-01-01

    We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 104 and 106, spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies. © the Partner Organisations 2014.

  19. Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water.

    Science.gov (United States)

    Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2014-08-21

    We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 10(4) and 10(6), spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies.

  20. The Use of VMD Data/Model to Test Different Thermodynamic Models for Vapour-Liquid Equilibrium

    DEFF Research Database (Denmark)

    Abildskov, Jens; Azquierdo-Gil, M.A.; Jonsson, Gunnar Eigil

    2004-01-01

    Vacuum membrane distillation (VMD) has been studied as a separation process to remove volatile organic compounds from aqueous streams. A vapour pressure difference across a microporous hydrophobic membrane is the driving force for the mass transport through the membrane pores (this transport takes...... place in vapour phase). The vapour pressure difference is obtained in VMD processes by applying a vacuum on one side of the membrane. The membrane acts as a mere support for the liquid-vapour equilibrium. The evaporation of the liquid stream takes place on the feed side of the membrane......, and the condensation on the permeate side of the membrane. The paper focus on aroma stripping using VMD; factors influencing flux and separation performance using selected model aroma compounds have been studied. Mainly the following parameters have been examined-aroma compounds: activity coefficient/vapour pressure...

  1. Urea free and more efficient sample preparation method for mass spectrometry based protein identification via combining the formic acid-assisted chemical cleavage and trypsin digestion.

    Science.gov (United States)

    Wu, Shuaibin; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-10-30

    A formic acid (FA)-assisted sample preparation method was presented for protein identification via mass spectrometry (MS). Detailedly, an aqueous solution containing 2% FA and dithiothreitol was selected to perform protein denaturation, aspartic acid (D) sites cleavage and disulfide linkages reduction simultaneously at 108°C for 2h. Subsequently, FA wiped off via vacuum concentration. Finally, iodoacetamide (IAA) alkylation and trypsin digestion could be performed ordinally. A series of model proteins (BSA, β-lactoglobulin and apo-Transferrin) were treated respectively using such method, followed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The identified peptide number was increased by ∼ 80% in comparison with the conventional urea-assisted sample preparation method. Moreover, BSA identification was achieved efficiently down to femtomole (25 ± 0 sequence coverage and 16 ± 1 peptides) via such method. In contrast, there were not peptides identified confidently via the urea-assisted method before desalination via the C18 zip tip. The absence of urea in this sample preparation method was an advantage for the more favorable digestion and MALDI-TOF MS analysis. The performances of two methods for the real sample (rat liver proteome) were also compared, followed by a nanoflow reversed-phase liquid chromatography with electrospray ionization tandem mass spectrometry system analysis. As a result, 1335 ± 43 peptides were identified confidently (false discovery rate method, corresponding to 295 ± 12 proteins (of top match=1 and requiring 2 unique peptides at least). In contrast, there were only 1107 ± 16 peptides (corresponding to 231 ± 10 proteins) obtained from the conventional urea-assisted method. It was serving as a more efficient protein sample preparation method for researching specific proteomes better, and providing assistance to develop other proteomics analysis methods, such as, peptide

  2. Technical note: Water vapour concentration and flux measurements with PTR-MS

    Directory of Open Access Journals (Sweden)

    C. Ammann

    2006-01-01

    Full Text Available The most direct approach for measuring the exchange of biogenic volatile organic compounds between terrestrial ecosystems and the atmosphere is the eddy covariance technique. It has been applied several times in the last few years using fast response proton-transfer-reaction mass spectrometry (PTR-MS. We present an independent validation of this technique by applying it to measure the water vapour flux in comparison to a common reference system comprising an infra-red gas analyser (IRGA. Water vapour was detected in the PTR-MS at mass 37 (atomic mass units corresponding to the cluster ion H3O+·H2O. During a five-week field campaign at a grassland site, we obtained a non-linear but stable calibration function between the mass 37 signal and the reference water vapour concentration. With a correction of the high-frequency damping loss based on empirical ogive analysis, the eddy covariance water vapour flux obtained with the PTR-MS showed a very good agreement with the flux of the reference system. The application of the empirical ogive method for high-frequency correction led to significantly better results than using a correction based on theoretical spectral transfer functions. This finding is attributed to adsorption effects on the tube walls that are presently not included in the theoretical correction approach. The proposed high-frequency correction method can also be used for other trace gases with different adsorption characteristics.

  3. Modelling and interpreting the isotopic composition of water vapour in convective updrafts

    Directory of Open Access Journals (Sweden)

    M. Bolot

    2013-08-01

    Full Text Available The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener–Bergeron–Findeisen process. As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

  4. Compressibility and specific heats of heavier condensed rare gases near the liquid-vapour critical point

    CERN Document Server

    March, N H

    2003-01-01

    Sarkisov (J. Chem. Phys. 119, 373, 2003) has recently discussed the structural behaviour of a simple fluid near the liquid-vapour critical point. His work, already compared with computer simulation studies, is here brought into direct contact for the heavier condensed rare gases Ar, Kr and Xe with (a) experiment and (b) earlier theoretical investigations. Directions for future studies then emerge.

  5. Reaction of soda-lime-silica glass melt with water vapour at melting temperatures

    Czech Academy of Sciences Publication Activity Database

    Vernerová, Miroslava; Kloužek, Jaroslav; Němec, Lubomír

    2015-01-01

    Roč. 416, MAY 15 (2015), s. 21-30 ISSN 0022-3093 R&D Projects: GA TA ČR TA01010844 Institutional support: RVO:67985891 Keywords : glass melt * sulfate * water vapour * bubble nucleation * melt foaming * glass melting Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.825, year: 2015

  6. Behaviour of carbon dioxide and water vapour flux densities from a disturbed raised peat bog

    NARCIS (Netherlands)

    Nieveen, J.P.; Jacobs, A.F.G.

    2002-01-01

    Measurements of carbon dioxide and water vapour flux densities were carried out for a disturbed raised peat bog in the north of the Netherlands during an 18 month continuous experiment. Tussock grass (sp. Molinea caerulae) mainly dominated the vegetation of the bog area. The maximum leaf area index

  7. Characterisation of vapour phase grown CdTe and (Cd,Zn)Te for detector applications

    CERN Document Server

    Fiederle, M; Rogalla, M; Meinhardt, J; Ludwig, J; Runge, K; Benz, W

    1999-01-01

    The growth of CdTe from the vapour phase offers several improvements in crystal quality and homogeneity. CdTe and (Cd, Zn)Te were grown by the modified Markov technique. The transport properties and the detector performance are given and compared to melt grown material. (author)

  8. On the representativity of water vapour measurements at Boulder for global stratospheric trends

    Science.gov (United States)

    Lossow, S.

    2016-12-01

    Long-term changes of water vapour in the lower stratosphere inevitably affect the surface climate. Thus understanding such changes is of primary importance. The longest continuous data set is based on balloon-borne frost point hygrometer observations at Boulder. Overall this data set shows an increase in water vapour since the 1980s accompanied by large variability on short time scales (Hurst et al., 2011). Recently a merged satellite data set, covering the time period between 1988 and 2010, has been analysed showing a decrease of water vapour in the lower stratosphere (Hegglin et al., 2014). This discrepancy is difficult to reconcile. There might be problems with one data set or even with both. Also the local behaviour at Boulder might not be representative for the zonal mean behaviour, which is represented by the satellite observations. So far this has been assumed and the Boulder changes have even been considered to be globally representative. Here I present investigations of this aspect using both model simulations and observations. References: Hegglin et al. (2014), "Vertical structure of stratospheric water vapour trends derived from merged satellite data", Nature Geoscience, 7, 768 - 776, doi:10.1038/ngeo2236. Hurst et al. (2011), "Stratospheric water vapor trends over Boulder, Colorado: Analysis of the 30 year Boulder record", Journal of Geophysical Research, 116, D02,306, doi:10.1029/2010JD015065.

  9. Analysis of atmospheric concentrations of quinones and polycyclic aromatic hydrocarbons in vapour and particulate phases

    Science.gov (United States)

    Delgado-Saborit, Juana Maria; Alam, Mohammed S.; Godri Pollitt, Krystal J.; Stark, Christopher; Harrison, Roy M.

    2013-10-01

    Polycyclic aromatic hydrocarbons (PAH) are often measured in studies of atmospheric chemistry or health effects of air pollution, due to their known human carcinogenicity. In recent years, PAH quinone derivatives have also become a focus of interest, primarily because they can contribute to oxidative stress. This work reports concentrations of 17 PAH and 15 quinones measured in air samples collected at a trafficked roadside. Data are presented for four compounds not previously reported in ambient air: 2-methyl-1,4-naphthoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, methyl-1,4-benzoquinone and 2,3-dimethylanthraquinone, and a large vapour phase component is measured, not analysed in most earlier studies. Analyses are reported also for SRM 1649a and 1649b, including many compounds (8 for SRM 1649a and 12 for SRM 1649b) for which concentrations have not previously been reported. This work assesses the vapour/particle phase distribution of PAHs and quinones in relation to their molecular weight, vapour pressure, polarity and Henry's Law constant, finding that both molecular weight and vapour pressure (which are correlated) are good predictors of the partitioning.

  10. Accuracy and conservatism of vapour intrusion algorithms for contaminated land management

    NARCIS (Netherlands)

    Provoost, J.; Reijnders, L.; Bonders, J.

    2013-01-01

    This paper provides a view on the suitability of screening-level vapour intrusion (VI) algorithms for contaminated land management. It focuses on the accuracy and level of conservatism for a number of screening-level algorithms used for VI into buildings. The paper discusses the published evidence

  11. Hydrogen and carbon vapour pressure isotope effects in liquid fluoroform studied by density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Oi, Takao; Mitome, Ryota; Yanase, Satoshi [Sophia Univ., Tokyo (Japan). Faculty of Science and Technology

    2017-06-01

    H/D and {sup 12}C/{sup 13}C vapour pressure isotope effects (VPIEs) in liquid fluoroform (CHF{sub 3}) were studied at the MPW1PW91/6-31 ++ G(d) level of theory. The CHF{sub 3} monomer and CHF{sub 3} molecules surrounded by other CHF{sub 3} molecules in every direction in CHF{sub 3} clusters were used as model molecules of vapour and liquid CHF{sub 3}. Although experimental results in which the vapour pressure of liquid {sup 12}CHF{sub 3} is higher than that of liquid {sup 12}CDF{sub 3} and the vapour pressure of liquid {sup 13}CHF{sub 3} is higher than that of liquid {sup 12}CHF{sub 3} between 125 and 212 K were qualitatively reproduced, the present calculations overestimated the H/D VPIE and underestimated the {sup 12}C/{sup 13}C VPIE. Temperature-dependent intermolecular interactions between hydrogen and fluorine atoms of neighbouring molecules were required to explain the temperature dependences of both H/D and {sup 12}C/{sup 13}C VPIEs.

  12. Vapour phase alkylation of ethylbenzene with t-butyl alcohol over ...

    Indian Academy of Sciences (India)

    Unknown

    catalysts pose problems such as difficulty in handling, safety, corrosion, waste disposal and difficulties in product separation. Even heterogeneous catalysts like kieselghur- supported phosphoric acid, used for the production of cumene, are also felt to be undesirable owing to release of acid vapours. The first solid acid ...

  13. The beauty of frost: nano-sulfur assembly via low pressure vapour deposition.

    Science.gov (United States)

    Wang, Yu; Chen, Lu; Scudiero, Louis; Zhong, Wei-Hong

    2015-11-14

    A low pressure vapour deposition (LPVD) technique is proposed as an environmentally friendly, cost-effective and versatile strategy for fabrication of sulfur nanomaterials. By controlling the characteristics of the deposit substrate for the LPVD, various sulfur-based nanomaterials have been obtained through a substrate-induced self-assembly process.

  14. The time variation in infrared water-vapour bands in Mira variables

    NARCIS (Netherlands)

    Matsuura, M; Yamamura, [No Value; Cami, J; Onaka, T; Murakami, H; Yamamura, I.

    The time variation in the water-vapour bands in oxygen-rich Mira variables has been investigated using multi-epoch ISO/SWS spectra of four Mira variables in the 2.5-4.0 mum region. All four stars show H2O bands in absorption around minimum in the visual light curve. At maximum, H2O emission features

  15. GPS sensing of precipitable water vapour during the March 2010 Melbourne storm

    Science.gov (United States)

    Choy, S.; Wang, C.; Zhang, K.; Kuleshov, Y.

    2013-11-01

    The March 2010 Melbourne storm is used as a case study to examine the potential of using Global Positioning System (GPS) observations for studying the precipitable water vapour (PWV) field. The Victorian statewide GPS infrastructure network, i.e. GPSnet, was used in this study. GPSnet is currently the only statewide and densest GPS infrastructure network in Australia, which provides an excellent opportunity to examine the distribution of water vapour as the severe weather system passed over the state. Data from 15 GPSnet stations were processed over a one-week period, i.e. a few days prior to and after the storm passage, during which the course of the storm extended from the west to the southeast corner of the state. In addition, data from two radiosonde sites of the Australian Bureau of Meteorology Upper Air Network were used to compare and validate the GPS derived PWV measurements. The findings demonstrate that there is strong spatial and temporal correlation between variations of the ground-based GPS-PWV estimates and the passage of the storm over the state. This is encouraging as the ground-based GPS water vapour sensing technique can be considered as a supplemental meteorological sensor in studying severe weather events. The advantage of using ground-based GPS-PWV technique is that it is capable of providing continuous observation of the storm passage with high temporal resolution. The spatial resolution of the distribution of water vapour is dependent on the geographical location and density of the GPS stations.

  16. Axial mercury vapour pressure distributions in DC operated low pressure mercury argon discharges

    Science.gov (United States)

    Gielen, John; de Groot, Simon; van Dijk, Jan; van der Mullen, Joost

    2000-10-01

    In a steady state DC operated (cylindrical) low pressure mercury argon discharge, an electric field exists in axial direction which results in a non-uniform axial mercury vapour pressure distribution; this phenomenon is termed cataphoresis. In a discharge tube covered with a fluorescent powder this gives in a non-uniform axial light distribution. Towards lighting applications this is a potential disadvantage, which is not present in AC operated fluorescent lamps. The dependence of the axial mercury vapour pressure distribution under DC operation on discharge tube and discharge parameters has been investigated. A model has been developed to predict the axial mercury vapour pressure distribution, in which the balance equations for particle and momentum conservation are solved in combination with a plasma physical model, and experiments have been performed to validate the model. In the present contribution the model and experimental results will be discussed and it will be demonstrated that the applied theoretical approach provides a better description of the axial mercury vapour pressure distribution compared to previous models known from literature.

  17. Water vapour rises from the cooling towers for the ATLAS detector at Point 1

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    Electronics on the ATLAS detector produce heat when the experiment is running. An elaborate cooling system keeps the detector from overheating. On the surface, the warm water vapour that rises from the detector 100metres underground is clearly visible from the ATLAS cooling towers on the CERN Meyrin site in Switzerland.

  18. Analysis of carbon dioxide, water vapour and energy fluxes over an ...

    Indian Academy of Sciences (India)

    Analysis of carbon dioxide, water vapour and energy fluxes over an Indian teak mixed deciduous forest for winter and summer months using eddy covariance technique ... Eddy covariance; Indian deciduous forests; CO2 flux; heat flux. ... National Remote Sensing Centre (ISRO), Balanagar, Hyderabad 500 037, India.

  19. Analysis of carbon dioxide, water vapour and energy fluxes over an ...

    Indian Academy of Sciences (India)

    temperate grassland ecosystem; Bound.-Layer Meteorol. 52 135–149. Mahrt L and Dean V 2002 Relationship of area-averaged carbon dioxide and water vapour fluxes to atmospheric variables; Agric. For. Meteor. 112 195–202. Ohtaki E 1984 Application of an infrared carbon dioxide and humidity instrument to studies of ...

  20. Study and mitigation of calibration error sources in a water vapour Raman lidar

    Science.gov (United States)

    David, Leslie; Bock, Olivier; Bosser, Pierre; Thom, Christian; Pelon, Jacques

    2014-05-01

    The monitoring of water vapour throughout the atmosphere is important for many scientific applications (weather forecasting, climate research, calibration of GNSS altimetry measurements). Measuring water vapour remains a technical challenge because of its high variability in space and time. The major issues are achieving long-term stability (e.g., for climate trends monitoring) and high accuracy (e.g. for calibration/validation applications). LAREG and LOEMI at Institut National de l'Information Géographique et Forestière (IGN) have developed a mobile scanning water vapour Raman lidar in collaboration with LATMOS at CNRS. This system aims at providing high accuracy water vapour measurements throughout the troposphere for calibrating GNSS wet delay signals and thus improving vertical positioning. Current developments aim at improving the calibration method and long term stability of the system to allow the Raman lidar to be used as a reference instrument. The IGN-LATMOS lidar was deployed in the DEMEVAP (Development of Methodologies for Water Vapour Measurement) campaign that took place in 2011 at the Observatoire de Haute Provence. The goals of DEMEVAP were to inter-compare different water vapour sounding techniques (lidars, operational and research radiosondes, GPS,…) and to study various calibration methods for the Raman lidar. A significant decrease of the signals and of the calibration constants of the IGN-LATMOS Raman lidar has been noticed all along the campaign. This led us to study the likely sources of uncertainty and drifts in each part of the instrument: emission, reception and detection. We inventoried several error sources as well as instability sources. The impact of the temperature dependence of the Raman lines on the filter transmission or the fluorescence in the fibre, are examples of the error sources. We investigated each error source and each instability source (uncontrolled laser beam jitter, temporal fluctuations of the photomultiplier

  1. Ballistic transport in graphene grown by chemical vapor deposition

    NARCIS (Netherlands)

    Calado, V.E.; Zhu, S.E.; Goswami, S.; Xu, Q.; Watanabe, K.; Taniguchi, T.; Janssen, G.C.A.M.; Vandersypen, L.M.K.

    2014-01-01

    In this letter, we report the observation of ballistic transport on micron length scales in graphene synthesised by chemical vapour deposition (CVD). Transport measurements were done on Hall bar geometries in a liquid He cryostat. Using non-local measurements, we show that electrons can be

  2. Chemical nature of catalysts of oxide nanoparticles in environment ...

    Indian Academy of Sciences (India)

    Carbon nanostructures (CNS) are often grown using oxide nanoparticles as catalyst in chemical vapour deposition and these oxides are not expected to survive as such during growth. In the present study, the catalysts of cobalt- and nickel oxide-based nanoparticles of sizes varying over a range have been reduced at 575 ...

  3. 12 Nigerian Journal of Chemical Research Vol. 19, 2014 Ampicillin ...

    African Journals Online (AJOL)

    6735s

    occurs when metals come in contact with moisture, acids, bases, salts, aggressive metal polishes and other liquid chemicals. Other agents of corrosion are gaseous materials like acid vapours, formaldehyde gas, and sulphur containing and ammonia gases. When metals are exposed to corrosion agents within an electrical ...

  4. Chemical modification/grafting of mesoporous alumina with polydimethylsiloxane (PDMS)

    NARCIS (Netherlands)

    Pinheiro de Melo, A.F.; Nijmeijer, Arian; Sripathi, V.G.P.; Winnubst, Aloysius J.A.

    2015-01-01

    A method for polydimethylsiloxane grafting of alumina powders is described which involves chemical modification of the surface of mesoporous (5 nm) γ-alumina flakes with a linker (3-aminopropyltriethoxysilane: APTES), either by a solution phase (SPD) or a vapour phase (VPD) reaction, followed by

  5. Leakage of volatile anaesthetics from agent-specific keyed vapourizer filling devices

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J.M.; Strunin, L.; Craig, D.B.

    1982-09-01

    Agent-specific keyed vapourizer filling devices were designed to ensure that an anaesthetic vapourizer is filled with the correct agent. Since there appear to be no reports of possible loss of volatile agent or operating room pollution resulting from either the design or patterns of use of these devices, measurements were made with three anaesthetic agents and two methods of use. First, two bottles each of methoxyflurane, enflurane and halothane were fitted with a suitable filling device and the weight of agent lost from each bottle over six weeks was measured. Bottle number 1 of each agent remained without agitation between weighings; bottle number 2 was tipped to mimic filling of a vapourizer. Weight loss over the six week period was 2.76 and 3.15 per cent of the halothane, 2.22 and 2.43 per cent of the enflurane, and 0.58 and 0.96 per cent of the methoxyflurane, for bottles number 1 and number 2, respectively. Second, pollution was measured with an infra-red analyser for halothane, using bottles number 1 and number 2, as described above, and a third bottle on which the filling device was replaced by the screw-on cap after each filling of the vapourizer. Vapour loss was undetectable for bottle number 1, between 25 and 30 ppm for bottle number 2, and between 350 and 400 ppm for bottle number 3. Thus, although the design of the filling devices results in loss of the anaesthetic agent, this loss represents potential pollution only when the device is replaced by the screw-on cap between use. Therefore, when using filling devices, these should be left on the bottle of volatile agent between fillings to decrease operating room pollution.

  6. The effects of substituent position on kinetics of benzene vapour adsorption onto 3-phenylphenoxy substituted metal-free and metallo-phthalocyanines thin films.

    Science.gov (United States)

    Alamin Ali, Haytham Elzien; Can, Nursel; Altun, Selçuk; Odabaş, Zafer

    2016-11-14

    The preparation of metal-free, Zn(ii), In(iii), and Cu(ii)-phthalocyanines containing tetrakis-(3-phenylphenoxy) groups was achieved by employing 3-(3-phenylphenoxy)phthalonitrile (1) and 4-(3-phenylphenoxy)phthalonitrile (2) as starting materials. The phthalonitriles and phthalocyanines were characterized by elemental analysis, infrared, proton nuclear magnetic resonance, ultraviolet-visible, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopic techniques. The effect of the substituent group on the kinetics of benzene vapour adsorption onto these novel compounds was examined using three kinetics models: the pseudo first-order model, the Elovich equation, and a simple adsorption-desorption model. Results show that the benzene adsorption kinetics strongly depend on the position of the substituent groups.

  7. Task Group report to the Assistant Secretary for Environment, Safety and Health on oversight of chemical safety at the Department of Energy. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    This report presents the results of a preliminary review of chemical safety within the Department of Energy (DOE). The review was conducted by Chemical Safety Oversight Review (CSOR) Teams composed of Office of Environment, Safety and Health (EH) staff members and contractors. The primary objective of the CSOR was to assess, the safety status of DOE chemical operations and identify any significant deficiencies associated with such operations. Significant was defined as any situation posing unacceptable risk, that is, imminent danger or threat to workers, co-located workers, the general public, or the environment, that requires prompt action by EH or the line organizations. A secondary objective of the CSOR was to gather and analyze technical and programmatic information related to chemical safety to be used in conjunction with the longer-range EH Workplace Chemical Accident Risk Review (WCARR) Program. The WCARR Program is part of the ongoing EH oversight of nonnuclear safety at all DOE facilities. `` The program objective is to analyze DOE and industry chemical safety programs and performance and determine the need for additional or improved safety guidance for DOE. During the period June 6, 1992, through July 31, 1992, EH conducted CSORs at five DOE sites. The sites visited were Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 Plant (Y-12), Oak Ridge National Laboratory (ORNL), and Lawrence Livermore National Laboratory (LLNL).

  8. Fluid geochemistry applications in reservoir engineering (vapour-dominated systems)

    Energy Technology Data Exchange (ETDEWEB)

    D' Amore, F.; Celati, R.; Calore, C.

    1982-01-01

    Fluid geochemistry has proved to be a valid tool for analyzing the processes occurring in geothermal reservoirs. The major effort is now invested in developing conceptual and quantitative models for chemical and physical processes that could produce the observed variations in fluid composition. These models are an effective complement to the classical methods of reservoir engineering in field development and exploitation. The fields in which the geochemical methods seem to be most effective are listed. Previous work in the field, as well as current development of research conducted on gas composition, is discussed and reviewed.

  9. Numerical Simulation of Pulsation Flow in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

    Science.gov (United States)

    Seryakov, A. V.; Konkin, A. V.

    2017-11-01

    The results of the numerical simulation of pulsations in the Laval-liked vapour channel of short low-temperature range heat pipes (HPs) are presented. The numerical results confirmed the experimentally obtained increase of the frequency of pulsations in the vapour channel of short HPs with increasing overheat of the porous evaporator relative to the boiling point of the working fluid. The occurrence of pressure pulsations inside the vapour channel in a short HPs is a complex phenomenon associated with the boiling beginning in the capillary-porous evaporator at high heat loads, and appearance the excess amount of vapour above it, leading to the increase in pressure P to a value at which the boiling point TB of the working fluid becomes higher than the evaporator temperature Tev. Vapour clot spreads through the vapour channel and condense, and then a rarefaction wave return from condenser in the evaporator, the boiling in which is resumed and the next cycle of the pulsations is repeated. Numerical simulation was performed using finite element method implemented in the commercial program ANSYS Multiphisics 14.5 in the two-dimensional setting of axis symmetric moist vapour flow with third kind boundary conditions.

  10. The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

    OpenAIRE

    Ernest N'Dri Koffi; Edward Graham; Andchristian Mätzler

    2013-01-01

    The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the “Swiss box”) to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 · 107 kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the ...

  11. Consistent vapour-liquid equilibrium data containing lipids

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Sarup, Bent

    Consistent physical and thermodynamic properties of pure components and their mixtures are important for process design, simulation, and optimization as well as design of chemical based products. In the case of lipids, it was observed a lack of experimental data for pure compounds and also...... compositions were calculated using Wilson, NRTL, UNIQUAC, and original UNIFAC models and bubble-point calculations. The relevance of enlarging experimental databank of lipids systems data in order to improve the performance of predictive thermodynamic models was confirmed in this work by analyzing...... the calculated values of original UNIFAC model and by proposing new interaction parameters for UNIFAC model and lipids systems. Also PC-SAFT model were analysed for lipids and a modification is proposed....

  12. New Inner Canalizing Technology with Vapour Hardening Material

    Directory of Open Access Journals (Sweden)

    Ďurove Juraj

    1999-09-01

    Full Text Available The Liner is a composite sandwich construction using multiple layers of Owens Corning Advantex extra corrosion resistant fiberglass, forming a complex unidirectional reinforced structure. This construction achives an unmatched strenght permitting a thinner wall and therefore less reduction of the original diameter. The ring stiffness is very important. The unique design of the Liner gives a very high E-Moduls performance of 10.000 MPa which is unmatched by any other liner on the market. The longitudial reinforcement ensures complete stability troughout the length and prevent any elongation caused by the installation process. The Liner is constructed using extra corrosion resistant fiberglass. The inside of the liner is covered with a polyester veil rich of resin, forming a very smooth and glass-hard surface. In Combination with the unique post-curing at 110 °C, a very high resistance to abrasion and chemicals is achieved.

  13. One year observation of water vapour isotopic composition at Ivittuut, Southern Greenland

    Science.gov (United States)

    Bonne, Jean-Louis; Masson-Delmotte, Valérie; Delmotte, Marc; Cattani, Olivier; Sodemann, Harald; Risi, Camille

    2013-04-01

    In September 2011, an automatic continuous water vapour isotopic composition monitoring instrument has been installed in the atmospheric station of Ivittuut (61.21° N, 48.17° W), southern Greenland. Precipitation has been regularly sampled on site at event to weekly scales and analysed in our laboratory for isotopic composition. Meteorological parameters (temperature, pressure, relative humidity, wind speed and direction) and atmospheric composition (CO2, CH4, Atmospheric Potential Oxygen) are also continuously monitored at Ivittuut. The meteorological context of our observation period will be assessed by comparison with the local climatology. The water vapour analyser is a Picarro Wavelength Scanned Cavity Ring-Down Spectrometer (WS-CRDS, model L2120i). It is automatically and regularly calibrated on the VSMOW scale using measurements of the isotopic composition of vaporized reference water standards using the Picarro Syringe Delivery Module (SDM). As measurements are sensitive to humidity level, an experimentally estimated calibration response function is used to correct our isotopic measurements. After data treatment, successive isotopic measurements of reference waters have a standard deviation of around 0.35 per mil for δ18O and 2.3 per mil for δD. Our instrumentation protocol and data quality control method will be presented, together with our one year δ18O, δD and d-excess measurements in water vapour and precipitation. The relationship between surface water vapour isotopic composition and precipitation isotopic composition will be investigated based on a distillation model. Specific difficulties linked to our low maintenance remote station will also be discussed. The processes responsible for the synoptic variability of Ivittuut water vapour isotopic composition will be investigated by comparing our observational dataset with (i) atmospheric back-trajectories and (ii) results from an isotopically-enabled atmospheric general circulation model (AGCM

  14. Rain- vapour isotopic interaction over the south-west coast of India

    Science.gov (United States)

    Palliyil Ravisankar, Lekshmy; Madhavan, Midhun; Rengaswamy, Ramesh

    2015-04-01

    Boundary layer water vapor isotopic composition (δv) is an important factor that controls the isotopic composition of evaporation flux and modulating the δ18O of tree ring cellulose through plant physiological cycle. But due to the difficult sampling procedure for water vapor, δv has rarely been quantified. Since many simple isotopic models require δvas an input, mostly we assume that the water vapor is in isotopic equilibrium with δof monthly rain (δr). Here we present simultaneous observations of water vapour (~ 300 samples) and rainfall (~200 samples) isotopic ratios from two stations in the south-west coast of India (both the stations are located in the west of Western Ghats), sampled during April- October, 2012. Daily rain water and water vapour (cryogenic trapping method) were collected according to the IAEA protocol and the isotopic analyses (D and 18O) were done using a Thermo Fisher Delta V+ Isotope Ratio Mass Spectrometer. We observe that, water vapour and rain are close to the equilibrium values during pre monsoon (April-May, ɛ = δr - δv= 8.9 ± 1.4 ), summer monsoon (June-September, ɛ = 9.0 ± 1.8 ) and North- East (NE) monsoon (October, ɛ = 7.9 ± 2.9 ) seasons. However, some individual rain events show more deviations from the equilibrium values. NE monsoon rainfall and water vapour are isotopically more depleted in 18O compared to the pre monsoon and summer monsoon seasons, in which the depletion is more in rain (~4 ) compared to water vapour (~2 ). This is because of the 18O enrichment of ground level vapour due to local evapo- transpiration (stations are at the leeward side of the Ghats), while rainfall is directly formed from the NE monsoon clouds which is more depleted in 18O. These results will be useful for the interpretation of δ18O of tree rings from south west.

  15. Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship

    KAUST Repository

    Adil, Karim

    2017-05-30

    The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques. Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities. Of special interest is the subclass of metal-organic frameworks (MOFs) with pore aperture sizes below 5-7 Å, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc. In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving. Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance.

  16. Precursors for use in vapour and solution phase thermolysis routes to II-VI thin films and nanodispersed oxide materials

    CERN Document Server

    Chunggaze, M

    1999-01-01

    Monothiocarbamates M(OSCNEt sub 2) sub 2 M = Cd (1) Zn (2) analogous to the dithiocarbamates (Et sub 2 NCS sub 2) sub 2 M which have been extensively studied for metal-organic chemical vapour deposition (MOCVD), have been prepared as alternative single-source precursors for depositing II-VI semiconducting materials. Structural analysis of (1) revealed a new, O-binucleating, bonding mode for the monothiocarbamato ligand resulting in polymeric chains which are co-aligned to give a distorted close-packed hexagonal array. The mixed alkyl zinc derivative [Et sub 4 Zn sub 4 (OSCNEt sub 2) sub 2 (NEt sub 2) sub 2] is formed as the only isolable product from the reaction of EtZnNEt sub 2 with carbonyl sulfide and also exhibits a second new bonding mode for the monothiocarbamato ligand in which both the oxygen and sulfur atoms are binucleating. Uniform adherent films of CdS films with various morphologies were grown on GaAs(100) and glass at substrate temperatures between 350-450 deg C. No oxygen incorporation within ...

  17. The Use of Bending Angle Retrieved By GPS Radio Occultation Technique For The Measurement of The Atmospheric Water Vapour Content

    Science.gov (United States)

    Vespe, F.; Benedetto, C.; Pacione, R.

    In the last decade the use of GPS radio occultation technique (GPS RO) has been deeply and widely investigated for retrieving physical and chemical Earth atmospheric parameters. The technique proved to be particularly precise in retrieving temperature profiles with an high vertical resolution (air) in 2 unknown (hydrostatic pressure and temperature). The system cannot be solved for lower troposphere because the water vapour pressu re is not negligible. So we are forced to include some other information such as the humidity computed by the models (ECMWF or NEP) or adding another observable in the system as the zenith troposphere delays estimated by the GPS ground stations. In this work we will investigate the possibility to retrieve humidity using only the bending angles achieved by the GPS RO. In particular, the humidity profiles are extracted differentiating the true bending angle profiles, retrieved by the GPS RO, with the dry ones, obtained by fitting and extrapolating the outer layers bending angles in a dry atmosphere model (exponential or Hopfield). The bending angles will be retrieved by CHAMP and SAC-C GPS RO data. Then the humidity profiles obtained with the proposed technique will be compared and validated with those retrieved with radio-sounding balloons over two sites at different latitudes: Brindisi (Italy) and Singapore (Japan).

  18. Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

    OpenAIRE

    Tamil Many K Thandavan; Siti Meriam Abdul Gani; Chiow San Wong; Roslan Md Nor

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as ...

  19. The Study for the Optimal Operation of D{sub 2}O Vapour Recovery System

    Energy Technology Data Exchange (ETDEWEB)

    Park, I.S.; Park, J.B. [Korea Electric Power Research Research Institute, Taejeon (Korea, Republic of)

    1997-12-31

    Digital control technology using micro-processor is widely used in Factory Automation area since 1980`s. However, the D{sub 2}O Vapour Recovery System in Wolsung 1 N.P.P is controlled by mechanical timer without considering the moisture condition in the Reactor Building and bed temperature, because it was designed using analog technology of 1960`s. This leads to the inefficient system operation and low D{sub 2}O recovery rate in addition to the high internal dose rate of operator. The goal of this phase II study is to develope a optimal automatic controller of D{sub 2}O vapour recovery system using PLC. We developed a control algorithm for Dual Tower Drier, a PLC control program, a operation change program and the monitoring system with a real-time simulator for system verification. (author). 15 refs., 11 figs., 2 tabs.

  20. Coal tar creosote abuse by vapour inhalation presenting with renal impairment and neurotoxicity: a case report

    Directory of Open Access Journals (Sweden)

    Hiemstra Thomas F

    2007-09-01

    Full Text Available Abstract A 56 year old aromatherapist presented with advanced renal failure following chronic coal tar creosote vapour inhalation, and a chronic tubulo-interstitial nephritis was identified on renal biopsy. Following dialysis dependence occult inhalation continued, resulting in seizures, ataxia, cognitive impairment and marked generalised cerebral atrophy. We describe for the first time a case of creosote abuse by chronic vapour inhalation, resulting in significant morbidity. Use of the polycyclic aromatic hydrocarbon-containing wood preservative coal tar creosote is restricted by many countries due to concerns over environmental contamination and carcinogenicity. This case demonstrates additional toxicities not previously reported with coal tar creosote, and emphasizes the health risks of polycyclic aromatic hydrocarbon exposure.

  1. Performance of a stationary diesel engine using vapourized ethanol as supplementary fuel

    Energy Technology Data Exchange (ETDEWEB)

    Ajav, E.A. [Ibadan Univ., Agricultural Engineering Dept., Ibadan (Nigeria); Singh, Bachchan [G.B. Pant Univ. of Agriculture and Technology, Coll. of Technology, Pantnagar (India); Bhattacharya, T.K. [G.B. Pant Univ. of Agriculture and Technology, Farm Machinery and Power Engineering Dept., Pantnagar (India)

    1998-12-31

    The modification and testing of a compression ignition engine using diesel and vapourized ethanol as fuel has been carried out. Tests on the engine fuelled with diesel only were made, and the performance evaluated to form a basis for comparison for those of ethanol-diesel dual fuelling. Modifications were made in the introduction of the ethanol and air. A carburettor was used to vaporize aqueous ethanol into the engine. The effect of preheating the intake ethanol-air mixture was also investigated. Performance was evaluated in terms of engine horsepower, brake specific fuel consumption, brake thermal efficiency, the exhaust gas temperature, lubricating oil temperature and exhaust emissions. The vapourized ethanol partially reduced diesel fuel consumption but also increased total fuel delivery. Vaporization increased power output, thermal efficiency and exhaust emission but lowered exhaust temperature and lubricating oil temperatures. (Author)

  2. Prediction of clay content from water vapour sorption isotherms considering hysteresis and soil organic matter content

    DEFF Research Database (Denmark)

    Arthur, E.; Tuller, M.; Møldrup, Per

    2015-01-01

    Soil texture, in particular the clay fraction, governs numerous environmental, agricultural and engineering soil processes. Traditional measurement methods for clay content are laborious and impractical for large-scale soil surveys. Consequently, clay prediction models that are based on water...... for estimating clay content from hygroscopic water at different relative humidity (RH) levels while considering hysteresis and organic matter content. Continuous adsorption/desorption vapour sorption isotherm loops were measured for 150 differently textured soils with a state-of-the-art vapour sorption analyser...... within a RH range from 3 to 93%. The clay contents, which ranged between 1 and 56%, were measured with a combination of sieving and sedimentation methods. Two regression models were developed for both adsorption and desorption at 10 RH levels (5, 10, 20, 30, 40, 50, 60, 70, 80 and 90%). While the first...

  3. Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour

    CERN Document Server

    Di Mauro, A; Piuz, François; Schyns, E M; Van Beelen, J B; Williams, T D

    2000-01-01

    The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow)

  4. Acoustic emission noise from sodium vapour bubble collapsing: detection, interpretation, modelling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dentico, G.; Pacilio, V.; Papalia, B.; Taglienti, S.; Tosi, V.

    1982-01-01

    Sodium vapour bubble collapsing is detected by means of piezoelectric accelorometers coupled to the test section via short waveguides. The output analog signal is processed by transforming it into a time series of pulses through the setting of an amplitude threshold and the shaping of a standard pulse (denominated 'event') every time the signal crosses that border. The number of events is counted in adjacent and equal time duration samples and the waiting time distribution between contiguous events is measured. Up to the moment, six kinetic properties have been found for the mentioned time series. They help in setting a stochastic model in which the subministration of energy into a liquid sodium medium induces the formation of vapour bubbles and their consequent collapsing delivers acoustic pulses. Finally, a simulation procedure is carried out: a Polya's urn model is adopted for simulating event sequences with a priori established requisites.

  5. Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Zhan, Hualin; Garrett, David J.; Apollo, Nicholas V.; Ganesan, Kumaravelu; Lau, Desmond; Prawer, Steven; Cervenka, Jiri

    2016-01-01

    High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm3, were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

  6. Influence of heat consumers distribution and flashing vapours effect on steam consumption of evaporation plant of sugar factory

    National Research Council Canada - National Science Library

    A. A. Gromkovskii

    2016-01-01

    The article considered the influence of the heat consumers distribution and the flashing vapours effect juice for multipleevaporator sugar factory on the consumption the main production flow of heat transfer agent – water vapor...

  7. Remote sensing of water vapour profiles in the framework of the Total Carbon Column Observing Network (TCCON

    Directory of Open Access Journals (Sweden)

    M. Schneider

    2010-12-01

    Full Text Available We show that the near infrared solar absorption spectra recorded in the framework of the Total Carbon Column Observing Network (TCCON can be used to derive the vertical distribution of tropospheric water vapour. The resolution of the TCCON spectra of 0.02 cm−1 is sufficient for retrieving lower and middle/upper tropospheric water vapour concentrations with a vertical resolution of about 3 and 8 km, respectively. We document the good quality of the remotely-sensed profiles by comparisons with coincident in-situ Vaisala RS92 radiosonde measurements. Due to the high measurement frequency, the TCCON water vapour profile data offer novel opportunities for estimating the water vapour variability at different timescales and altitudes.

  8. The critical assessment of vapour pressure estimation methods for use in modelling the formation of atmospheric organic aerosol

    Directory of Open Access Journals (Sweden)

    M. H. Barley

    2010-01-01

    Full Text Available A selection of models for estimating vapour pressures have been tested against experimental data for a set of compounds selected for their particular relevance to the formation of atmospheric aerosol by gas-liquid partitioning. The experimental vapour pressure data (all <100 Pa of 45 multifunctional compounds provide a stringent test of the estimation techniques, with a recent complex group contribution method providing the best overall results. The effect of errors in vapour pressures upon the formation of organic aerosol by gas-liquid partitioning in an atmospherically relevant example is also investigated. The mass of organic aerosol formed under typical atmospheric conditions was found to be very sensitive to the variation in vapour pressure values typically present when comparing estimation methods.

  9. Optimal estimation of water vapour profiles using a combination of Raman lidar and microwave radiometer

    Science.gov (United States)

    Foth, Andreas; Pospichal, Bernhard

    2017-09-01

    In this work, a two-step algorithm to obtain water vapour profiles from a combination of Raman lidar and microwave radiometer is presented. Both instruments were applied during an intensive 2-month measurement campaign (HOPE) close to Jülich, western Germany, during spring 2013. To retrieve reliable water vapour information from inside or above the cloud a two-step algorithm is applied. The first step is a Kalman filter that extends the profiles, truncated at cloud base, to the full height range (up to 10 km) by combining previous information and current measurement. Then the complete water vapour profile serves as input to the one-dimensional variational (1D-VAR) method, also known as optimal estimation. A forward model simulates the brightness temperatures which would be observed by the microwave radiometer for the given atmospheric state. The profile is iteratively modified according to its error bars until the modelled and the actually measured brightness temperatures sufficiently agree. The functionality of the retrieval is presented in detail by means of case studies under different conditions. A statistical analysis shows that the availability of Raman lidar data (night) improves the accuracy of the profiles even under cloudy conditions. During the day, the absence of lidar data results in larger differences in comparison to reference radiosondes. The data availability of the full-height water vapour lidar profiles of 17 % during the 2-month campaign is significantly enhanced to 60 % by applying the retrieval. The bias with respect to radiosonde and the retrieved a posteriori uncertainty of the retrieved profiles clearly show that the application of the Kalman filter considerably improves the accuracy and quality of the retrieved mixing ratio profiles.

  10. Can painted glass felt or glass fibre cloth be used as vapour barrier?

    OpenAIRE

    El-Khattam, Amira; Andersen, Mie Them; Hansen, Kurt Kielsgaard; Møller, Eva B.

    2014-01-01

    In most Nordic homes the interior surfaces of walls and ceilings have some kind of surface treatment for aesthetical reasons. The treatments can for example be glass felt or glass fibre cloth which are painted afterwards.To evaluate the hygrothermal performance of walls and ceilings it is essential to know how much influence a surface treatment has on the water vapour transport. Traditionally, there has been most focus on paints that affect the permeability as little as possible. However, som...

  11. Computer simulation study of the nematic-vapour interface in the Gay-Berne model

    Science.gov (United States)

    Rull, Luis F.; Romero-Enrique, José Manuel

    2017-06-01

    We present computer simulations of the vapour-nematic interface of the Gay-Berne model. We considered situations which correspond to either prolate or oblate molecules. We determine the anchoring of the nematic phase and correlate it with the intermolecular potential parameters. On the other hand, we evaluate the surface tension associated to this interface. We find a corresponding states law for the surface tension dependence on the temperature, valid for both prolate and oblate molecules.

  12. A microwave satellite water vapour column retrieval for polar winter conditions

    Energy Technology Data Exchange (ETDEWEB)

    Perro, Christopher; Lesins, Glen; Duck, Thomas J.; Cadeddu, Maria

    2016-01-01

    A new microwave satellite water vapour retrieval for the polar winter atmosphere is presented. The retrieval builds on the work of Miao et al. (2001) and Melsheimer and Heygster (2008), employing auxiliary information for atmospheric conditions and numerical optimization. It was tested using simulated and actual measurements from the Microwave Humidity Sounder (MHS) satellite instruments. Ground truth was provided by the G-band vapour radiometer (GVR) at Barrow, Alaska. For water vapour columns less than 6 kg m-2, comparisons between the retrieval and GVR result in a root mean square (RMS) deviation of 0.39 kg m-2 and a systematic bias of 0.08 kg m-2. These results are compared with RMS deviations and biases at Barrow for the retrieval of Melsheimer and Heygster (2008), the AIRS and MIRS satellite data products, and the ERA-Interim, NCEP, JRA-55, and ASR reanalyses. When applied to MHS measurements, the new retrieval produces a smaller RMS deviation and bias than for the earlier retrieval and satellite data products. The RMS deviations for the new retrieval were comparable to those for the ERA-Interim, JRA-55, and ASR reanalyses; however, the MHS retrievals have much finer horizontal resolution (15 km at nadir) and reveal more structure. The new retrieval can be used to obtain pan-Arctic maps of water vapour columns of unprecedented quality. It may also be applied to measurements from the Special Sensor Microwave/Temperature 2 (SSM/T2), Advanced Microwave Sounding Unit B (AMSU-B), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Technology Microwave Sounder (ATMS), and Chinese MicroWave Humidity Sounder (MWHS) instruments.

  13. Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

    DEFF Research Database (Denmark)

    Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

    2016-01-01

    Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of ...... with increasing VPD and may necessitate revision of current models based on this assumption....

  14. The influence of heat pre-treatment on the sorption of water vapour on bentonite

    Czech Academy of Sciences Publication Activity Database

    Mokrejš, P.; Zikánová, Arlette; Hradil, David; Štulík, K.; Pacáková, V.; Kočiřík, Milan; Eić, M.

    2005-01-01

    Roč. 11, č. 1 (2005), s. 57-63 ISSN 0929-5607 R&D Projects: GA ČR(CZ) GA104/02/1464; GA MŠk(CZ) LN00A028 Institutional research plan: CEZ:AV0Z40400503 Keywords : adsorption * bentonite * montmorillonite * water vapour Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.323, year: 2005

  15. Enhanced performance of a wide-aperture copper vapour laser with ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... A wide-aperture copper vapour laser was demonstrated at ∼ 10 kHz rep-rate with hydrogen additive in its buffer gas. Maximum power in excess of ∼ 50 W (at 10 kHz) was achieved by adding 1.96% hydrogen to the neon buffer gas at 20 mbar total gas pressure. This increase in output power was about ...

  16. Ultrasound assisted synthesis of PANI/ZnMoO4 nanocomposite for simultaneous improvement in anticorrosion, physico-chemical properties and its application in gas sensing.

    Science.gov (United States)

    Bhanvase, B A; Darda, N S; Veerkar, N C; Shende, A S; Satpute, S R; Sonawane, S H

    2015-05-01

    Ultrasound assisted in-situ semi-batch emulsion polymerization has been used for the preparation of polyaniline (PANI) and PANI/ZnMoO4 nanocomposite with different loading of ZnMoO4 (ZM) nanoparticles. ZM nanoparticles were functionalized using Myristic acid (MA) for better compatibility with PANI. The cavitational effects induced due to ultrasonic irradiations have been shown significant enhancement in the dispersion of functionalized ZM nanoparticles into the PANI during ultrasound assisted in-situ emulsion polymerization process. TEM images of PANI/ZM nanocomposite particles give the direct evidence of fine dispersion and encapsulation of MA treated ZM nanoparticles in PANI matrix. The presence of ZM nanoparticles in PANI/ZM nanocomposite shows significant improvement in the mechanical (cross-cut adhesion), thermal, anticorrosion and sensing properties of PANI/ZM nanocomposite/alkyd coatings over PANI/alkyd and neat alkyd resin coating. Fine and uniform dispersion of ZM nanoparticles in PANI matrix using this novel synthesis method (PANI (p-type)/ZM (n-type) hetero-junction) improves LPG sensing ability and minimizes response time to sense LPG significantly compared with neat PANI. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Simplified heat transfer modeling for Vapour Phase Soldering based on filmwise condensation for different horizontal Printed Circuit Boards

    Science.gov (United States)

    Géczy, Attila; Illés, Balázs; Péter, Zsolt; Illyefalvi-Vitéz, Zsolt

    2015-03-01

    The paper presents a method for investigating heat transfer during a specific reflow soldering method, Vapour Phase Soldering (VPS), where a horizontal Printed Circuit Board (PCB) is heated in vapour medium. The paper presents refined descriptions of filmwise condensation which were investigated and adjusted for the VPS process. The results show a proper and fast approximation of measurements. The dependence of the PCB characteristic length is also investigated.

  18. Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

    Science.gov (United States)

    Bykovskiy, D. P.; Petrovskii, V. N.; Uspenskiy, S. A.

    2015-03-01

    The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study.

  19. Drunk bugs: Chronic vapour alcohol exposure induces marked changes in the gut microbiome in mice.

    Science.gov (United States)

    Peterson, Veronica L; Jury, Nicholas J; Cabrera-Rubio, Raúl; Draper, Lorraine A; Crispie, Fiona; Cotter, Paul D; Dinan, Timothy G; Holmes, Andrew; Cryan, John F

    2017-04-14

    The gut microbiota includes a community of bacteria that play an integral part in host health and biological processes. Pronounced and repeated findings have linked gut microbiome to stress, anxiety, and depression. Currently, however, there remains only a limited set of studies focusing on microbiota change in substance abuse, including alcohol use disorder. To date, no studies have investigated the impact of vapour alcohol administration on the gut microbiome. For research on gut microbiota and addiction to proceed, an understanding of how route of drug administration affects gut microbiota must first be established. Animal models of alcohol abuse have proven valuable for elucidating the biological processes involved in addiction and alcohol-related diseases. This is the first study to investigate the effect of vapour route of ethanol administration on gut microbiota in mice. Adult male C57BL/6J mice were exposed to 4 weeks of chronic intermittent vapourized ethanol (CIE, N=10) or air (Control, N=9). Faecal samples were collected at the end of exposure followed by 16S sequencing and bioinformatic analysis. Robust separation between CIE and Control was seen in the microbiome, as assessed by alpha (pdiversity, with a notable decrease in alpha diversity in CIE. These results demonstrate that CIE exposure markedly alters the gut microbiota in mice. Significant increases in genus Alistipes (pgut-brain axis and align with previous research showing similar microbiota alterations in inflammatory states during alcoholic hepatitis and psychological stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Production of sulphate-rich vapour during the Chicxulub impact and implications for ocean acidification

    Science.gov (United States)

    Ohno, Sohsuke; Kadono, Toshihiko; Kurosawa, Kosuke; Hamura, Taiga; Sakaiya, Tatsuhiro; Shigemori, Keisuke; Hironaka, Yoichiro; Sano, Takayoshi; Watari, Takeshi; Otani, Kazuto; Matsui, Takafumi; Sugita, Seiji

    2014-04-01

    The mass extinction event at the Cretaceous/Palaeogene boundary 65.5 Myr ago has been widely attributed to the Chicxulub impact, but the mechanisms of extinction remain debated. In the oceans, near-surface planktonic foraminifera suffered severe declines, in contrast to the relatively high survival rates of bottom-dwelling benthic foraminifera. The vapour produced by an impact into Chicxulub's target rocks, which include sulphate-rich anhydrite, could have led to global acid rain, which can explain the pattern of oceanic extinctions. However, it has been suggested that most of the sulphur in the target rocks would have been released as sulphur dioxide and would have stayed in the stratosphere for a long time. Here we show, from impact experiments into anhydrite at velocities exceeding 10 km s-1, that sulphur trioxide dominates over sulphur dioxide in the resulting vapour cloud. Our experiments suggest that the Chicxulub impact released a huge quantity of sulphur trioxide into the atmosphere, where it would have rapidly combined with water vapour to form sulphuric acid aerosol particles. We also find, using a theoretical model of aerosol coagulation following the Chicxulub impact, that larger silicate particles ejected during the impact efficiently scavenge sulphuric acid aerosol particles and deliver the sulphuric acid to the surface within a few days. The rapid surface deposition of sulphuric acid would cause severe ocean acidification and account for preferential extinction of planktonic over benthic foraminifera.