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Sample records for wet chemical preparation

  1. Indium tin oxide films prepared via wet chemical route

    International Nuclear Information System (INIS)

    Legnani, C.; Lima, S.A.M.; Oliveira, H.H.S.; Quirino, W.G.; Machado, R.; Santos, R.M.B.; Davolos, M.R.; Achete, C.A.; Cremona, M.

    2007-01-01

    In this work, indium tin oxide (ITO) films were prepared using a wet chemical route, the Pechini method. This consists of a polyesterification reaction between an α-hydroxicarboxylate complex (indium citrate and tin citrate) with a polyalcohol (ethylene glycol) followed by a post annealing at 500 deg. C. A 10 at.% of doping of Sn 4+ ions into an In 2 O 3 matrix was successfully achieved through this method. In order to characterize the structure, the morphology as well as the optical and electrical properties of the produced ITO films, they were analyzed using different experimental techniques. The obtained films are highly transparent, exhibiting transmittance of about 85% at 550 nm. They are crystalline with a preferred orientation of [222]. Microscopy discloses that the films are composed of grains of 30 nm average size and 0.63 nm RMS roughness. The films' measured resistivity, mobility and charge carrier concentration were 5.8 x 10 -3 Ω cm, 2.9 cm 2 /V s and - 3.5 x 10 20 /cm 3 , respectively. While the low mobility value can be related to the small grain size, the charge carrier concentration value can be explained in terms of the high oxygen concentration level resulting from the thermal treatment process performed in air. The experimental conditions are being refined to improve the electrical characteristics of the films while good optical, chemical, structural and morphological qualities already achieved are maintained

  2. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  3. Characterization of silver nanoparticles prepared by wet chemical ...

    African Journals Online (AJOL)

    Results: The silver nanoparticles formed were spherical in shape with mean size of 10.3 nm. The ... antibacterial activity against various strains of bacteria. Keywords: Wet ..... Fang J, Zhong C, Mu R. The study of deposited silver particulate ...

  4. Zirconia thin film preparation by wet chemical methods at low temperature

    NARCIS (Netherlands)

    Popovici, M.; Graaf, de J.; Verschuuren, M.A.; Graat, P.C.J.; Verheijen, M.A.

    2010-01-01

    In this study the preparation of zirconia thin films with a high refractive index at low temperature is aimed for. Two non-hydrolytic type approaches of wet chemical synthesis are presented. Both by sol–gel and colloid chemistry, highly transmissive, smooth thin films of zirconia cubic and/or

  5. Characterization and photo-chemical applications of nano-ZnO prepared by wet chemical and thermal decomposition methods

    International Nuclear Information System (INIS)

    Mousa, M.A.; Bayoumy, W.A.A.; Khairy, M.

    2013-01-01

    Graphical abstract: - Highlights: • Nano-ZnO particles were synthesized by soft-wet precipitation and dry methods. • ZnO nanoparticle with different morphologies was obtained. • Nano ZnO samples showed a high photocatalytic activity. • ZnO nanoparticle showed strong ultraviolet emission at room temperature. • The samples showed high biological activity depending on their synthetic method. - Abstract: Nano-crystalline ZnO particles were synthesized using two different routes: soft-wet and dry methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to identify the particles structures and morphologies, while X-ray diffraction (XRD) was used for verifying the particles crystal structure. The thermal stabilities of the particles were examined through thermal gravimetric analysis technique and their surface areas were calculated using BET method. Moreover, the photocatalytic activities were evaluated using UV–vis spectroscopy and photoluminescence (PL) characterization. The results showed that all the prepared ZnO samples possess a hexagonal wurtzite structure with high purity. Different particle sizes and morphologies of spheres, rods and wires were obtained depending on the preparation method used. Particle sizes obtained by the dry method are smaller than that found by the wet chemical method. The effects of both particle size and morphology on each of surface as well as optical properties, photocatalytic activity, dye/ZnO solar cell efficiency and biological activity have been studied and discussed

  6. Hysteresis losses in iron oxide nanoparticles prepared by glass crystallization or wet chemical precipitation

    International Nuclear Information System (INIS)

    Mueller, Robert; Dutz, Silvio; Hergt, Rudolf; Schmidt, Christopher; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    2007-01-01

    Ferrofluids were prepared from glass crystallized as well as wet precipitated iron oxide particles. Comparing hysteresis losses versus applied field amplitude from particles in immobilized state (powder) and in fluid state (ferrofluid) shows in some cases anomalous large losses at low magnetic fields. The influence of texture on the losses was investigated

  7. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  8. Enhanced local piezoelectric response in the erbium-doped ZnO nanostructures prepared by wet chemical synthesis

    Directory of Open Access Journals (Sweden)

    Reza Zamiri

    2017-03-01

    Full Text Available Pure and erbium (Er doped ZnO nanostructures were prepared by simple and cost effective wet chemical precipitation method. The successful doping with phase purity of prepared ZnO nanostructure was confirmed by X-ray diffraction (XRD and their Rietveld analysis. The change in structural morphology of nanoscale features of prepared ZnO nanopowders on Er doping was observed from their scanning electron microscopy (SEM images. The presence of Er in prepared ZnO nanopowder was further confirmed from corresponding energy dispersive X-ray spectroscopy (EDX spectra of scanned SEM images. Piezoelectric properties of before (green samples and after sintering of consolidated compact of synthesized nanopowders were successfully measured. The out-of-plane (effective longitudinal and in-plane (effective shear coefficients of the samples were estimated from the local piezoresponse.

  9. Microstructures, Mechanical Properties and Thermal Conductivities of W-0.5 wt.%TiC Alloys Prepared via Ball Milling and Wet Chemical Method

    Science.gov (United States)

    Lang, Shaoting; Yan, Qingzhi; Sun, Ningbo; Zhang, Xiaoxin; Ge, Changchun

    2017-10-01

    Two kinds of W-0.5 wt.%TiC alloys were prepared, one by ball milling and the other by the wet chemical method. For comparison, pure tungsten powders were chemically prepared and sintered by the same process. The microstructures, mechanical properties and thermal conductivities of the prepared samples were characterized. It has been found that the wet chemical method resulted in finer sizes and more uniform distribution of TiC particles in the sintered tungsten matrix than the ball milling method. The W-TiC alloy prepared by the wet chemical method achieved the highest bending strength (1065.72 MPa) among the samples. Further, it also exhibited obviously higher thermal conductivities in the temperature range of room temperature to 600°C than did the W-TiC alloy prepared by ball milling, but the differences in their thermal conductivities could be ignored in the range of 600-800°C.

  10. Investigation on structural and optical properties of ZnO film prepared by simple wet chemical method

    Science.gov (United States)

    Sholehah, Amalia; Mulyadi, Rendi; Haryono, Didied; Muttakin, Imamul; Rusbana, Tb Bahtiar; Mardiyanto

    2018-04-01

    ZnO thin layer has a broad potential application in electronic and optoelectronic devices. In this study, vertically align ZnO layers were deposited on ITO glass using wet chemistry method. The seed layers were prepared using electrodeposition technique at 3°C. The growing process was carried out using chemical bath deposition at 90°C. To improve the structural properties, two different hydrothermal treatment variations were applied separately. From the experiment, it is shown that the hydrothermal process using N2 gas has given the best result, with average diameter, crystallite size, and band-gap energy of 68.83 nm; 56.37 nm; and 3.16 eV, respectively.

  11. Extended phase homogeneity and electrical properties of barium calcium titanate prepared by the wet chemical methods

    International Nuclear Information System (INIS)

    Jayanthi, S.; Kutty, T.R.N.

    2004-01-01

    Ca-substituted BaTiO 3 with extended homogeneity range upto ∼50 mol% CaTiO 3 have been prepared by three different chemical routes namely carbonate-oxalate (COBCT), gel-carbonate (GCBCT), and gel-to-crystallite conversion (GHBCT) followed by heat treatment above 1150 deg. C. X-ray powder diffraction (XRD) data show continuous decrease in the tetragonal unit cell parameters as well as c 0 /a 0 ratio with CaTiO 3 content, which are in accordance with the substitution of smaller sized Ca 2+ ions at the barium sites. The microstructure as well as the dielectric properties are greatly influenced by the cationic ratio, α=(Ba+Ca)/Ti. The grain size decreases with CaTiO 3 content for the stoichiometric samples (α=1), whereas ultrafine microstructure is observed in the case of off-stoichiometric samples (α>1) for the whole compositional range of CaTiO 3 concentrations. Sharper ε r -T characteristics at lower calcium content and broader ε r -T with decreased ε max , in the higher calcium range are observed in the case of α=1. Whereas nanometer grained ceramics exhibiting diffuse ε r -T characteristics are obtained in the case of α>1. The positive temperature coefficient of resistivity (PTCR) is realized for barium calcium titanate ceramics having 0.3 at.% Sb as the donor dopant for higher CaTiO 3 (typically 30 mol%) containing samples (α=1), indicating that Ca 2+ ions do not behave as acceptors if they were to substitute at the Ti 4+ sites. Whereas the off-stoichiometric (α>1) ceramics retained high resistivity, indicative of the Ti-site occupancy for Ca 2+ in fine grain ceramics

  12. Role of Annealing Temperature on Morphology of Alumina Thin Film Prepared by Wet-Chemical Method

    Directory of Open Access Journals (Sweden)

    Manju Pandey

    2015-03-01

    Full Text Available In this paper, we reported the compositional, morphological and structural properties of the alumina(Al2O3 thin films prepared by sol-gel technique and annealed between 800 0C to 1200 0C for 1-hour in an air atmosphere. The deposited films were polycrystalline in nature. Thin films were found uniform and adherent to the alumina substrate. Effect of annealing temperature on structural parameters such as pore size and surface area were calculated. The result indicates that pore size and surface area was decreased by increasing annealing temperature. The material characterization was done by field emission scanning electron microscope (SEM, atomic force microscopy (AFM and Brunaur, Emmet and Teller (BET.

  13. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2013-11-01

    Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

  14. Wet-Chemical Preparation of Silicon Tunnel Oxides for Transparent Passivated Contacts in Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Köhler, Malte; Pomaska, Manuel; Lentz, Florian; Finger, Friedhelm; Rau, Uwe; Ding, Kaining

    2018-05-02

    Transparent passivated contacts (TPCs) using a wide band gap microcrystalline silicon carbide (μc-SiC:H(n)), silicon tunnel oxide (SiO 2 ) stack are an alternative to amorphous silicon-based contacts for the front side of silicon heterojunction solar cells. In a systematic study of the μc-SiC:H(n)/SiO 2 /c-Si contact, we investigated selected wet-chemical oxidation methods for the formation of ultrathin SiO 2 , in order to passivate the silicon surface while ensuring a low contact resistivity. By tuning the SiO 2 properties, implied open-circuit voltages of 714 mV and contact resistivities of 32 mΩ cm 2 were achieved using μc-SiC:H(n)/SiO 2 /c-Si as transparent passivated contacts.

  15. Structural, morphological, wettability and thermal resistance properties of hydro-oleophobic thin films prepared by a wet chemical process

    International Nuclear Information System (INIS)

    Phani, A.R.

    2006-01-01

    The structural properties of fluorine containing polymer compounds make them highly attractive materials for hydro-oleophobic applications. However, most of these exhibit low surface energy and poor adhesion on the substrates. In the present investigation, crack free, smooth and uniform thin films of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole] -co-tetrafluoroethylene (TFD-co-TFE) with good adhesion have been deposited by wet chemical spin-coating technique on polished AISI 440C steel substrates. The as-deposited films (xerogel films) have been subjected to annealing for 1 h at different temperatures ranging from 100 to 500 deg. C in an argon atmosphere. The size growth of the nano-hemispheres increased from 8 nm for xerogel film to 28 nm for film annealed at 400 deg. C. It was found that as the annealing temperature increased from 100 to 400 deg. C, nano-hemisphere-like structures were formed, which in turn have shown increase in the water contact angle from 122 deg. to 147 deg. and oil (peanut) contact angle from 85 deg. to 96 deg. No change in the water contact angle (122 deg.) has been observed when the films deposited at room temperature were heated in air from 30 to 80 deg. C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film

  16. Wet chemical synthesis of soluble gold nanogaps

    DEFF Research Database (Denmark)

    Jain, Titoo; Tang, Qingxin; Bjørnholm, Thomas

    2014-01-01

    NRs) in aqueous solution. Through controlled end-to-end assembly of the AuNRs into dimers or chains, facilitated via target molecules, they can be used as electrical contacts. In this way, the preparation of AuNR-molecule-AuNR junctions by wet chemical methods may afford a large number of identical devices...... with little variation in the interface between molecule and electrode (AuNR). In this Account, we highlight recent progress in using chemically synthesized AuNRs as building blocks for molecular electronic applications. We outline the general synthesis and properties of AuNRs and describe the aqueous growth...... in the nanogaps lets us spectroscopically characterize the molecules via surface-enhanced Raman scattering. We discuss the incorporation of oligopeptides functionalized with acetylene units having uniquely identifiable vibrational modes. This acetylene moiety allows chemical reactions to be performed in the gaps...

  17. The Synthesis of Anatase Nanoparticles and the Preparation of Photocatalytically Active Coatings Based on Wet Chemical Methods for Self-Cleaning Applications

    Directory of Open Access Journals (Sweden)

    Dejan Verhovšek

    2012-01-01

    Full Text Available We report on an improved sol-gel method for the production of highly photocatalytic titanium dioxide (TiO2 anatase nanoparticles which can provide appropriate control over the final characteristics of the nanoparticles, such as particle size, crystallinity, crystal structure, morphology, and also the degree of agglomeration. The synthesized anatase nanoparticles were characterized using various techniques, such as X-ray powder diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM, and were tested in coatings for self-cleaning glass and ceramic surfaces. The coatings were prepared using a soft chemistry route and are completely transparent to visible light and exhibit a high photocatalytic effect, which was determined by contact-angle measurements. Finally, it is worth mentioning that both the sol-gel synthesis method and the coating-preparation method are based on a wet chemical process, thus presenting no risk of handling the TiO2 anatase nanoparticles in their potentially hazardous powder form at any stage of our development. Low-price, easy-to-handle, and nontoxic materials were used. Therefore, our work represents an important contribution to the development of TiO2 anatase nanoparticle coatings that provide a high photocatalytic effect and can thus be used for numerous applications.

  18. Wet-Chemical Preparation of TiO2-Based Composites with Different Morphologies and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Liqin Xiang

    2017-10-01

    Full Text Available TiO2-based composites have been paid significant attention in the photocatalysis field. The size, crystallinity and nanomorphology of TiO2 materials have an important effect on the photocatalytic efficiency. The synthesis and photocatalytic activity of TiO2-based materials have been widely investigated in past decades. Based on our group’s research works on TiO2 materials, this review introduces several methods for the fabrication of TiO2, rare-earth-doped TiO2 and noble-metal-decorated TiO2 particles with different morphologies. We focused on the preparation and the formation mechanism of TiO2-based materials with unique structures including spheres, hollow spheres, porous spheres, hollow porous spheres and urchin-like spheres. The photocatalytical activity of urchin-like TiO2, noble metal nanoparticle-decorated 3D (three-dimensional urchin-like TiO2 and bimetallic core/shell nanoparticle-decorated urchin-like hierarchical TiO2 are briefly discussed.

  19. Annealing effect on the photoluminescence properties of ZnO nanorod array prepared by a PLD-assistant wet chemical method

    International Nuclear Information System (INIS)

    Wei Sufeng; Lian Jianshe; Wu Hua

    2010-01-01

    Well-aligned ZnO nanorod arrays were synthesized by a wet chemical method on the glass substrate with ZnO thin film as seed layer prepared by pulsed laser deposition. The effect of annealing temperature on the luminescence characteristics was investigated. As the annealing temperature increased, the photoluminescence properties show a general enhancing tendency. The nanorod array with high ultraviolet emission and negligible visible light emission (designated by the photoluminescence intensity ratio of ultraviolet to visible emission of 66.4) is obtained by annealing the sample at 700 deg. C for 1 h. Based on the results of X-ray photoelectron spectroscopy and photoluminescence spectra, the mechanisms of visible emission were discussed. - Research Highlights: → ZnO nanorod array with good crystallography, low defects concentration and good optical property was obtained after annealed at 700 deg. C for 1 h. → The transition from the conduction band to the O i level may be responsible for the yellow-green emission. → The yellow emission may originate from the presence of Zn(OH) 2 on the surface or the band transition from conduction band to V o Zn i level. → The transition from the Zn i level to the level should produce an orange emission or an orange-red emission.

  20. Wet milling versus co-precipitation in magnetite ferrofluid preparation

    Directory of Open Access Journals (Sweden)

    Almásy László

    2015-01-01

    Full Text Available Various uses of ferrofluids for technical applications continuously raise the interest in improvement and optimization of preparation methods. This paper deals with preparation of finely granulated magnetite particles coated with oleic acid in hydrocarbon suspensions following either chemical co-precipitation from iron salt precursors or wet milling of micron size magnetite powder with the goal to compare the benefits and disadvantages of each method. Microstructural measurements showed that both methods gave similar magnetite particle size of 10-15 nm. Higher saturation magnetization was achieved for the wet-milled magnetite suspension compared to relatively rapid co-precipitation synthesis. Different efficacies of ferrophase incorporation into kerosene could be related to the different mechanisms of oleic acid bonding to nanoparticle surface. The comparative data show that wet milling represents a practicable alternative to the traditional co-precipitation since despite of longer processing time, chemicals impact on environment can be avoided as well as the remnant water in the final product.

  1. Parametric optimisation of core–shell ZnS:Mn/ZnS nanoparticles prepared by ultrasound-controlled wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Suranjan, E-mail: suranjansen@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Solanki, Chetan Singh, E-mail: chetanss@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Sharma, Pratibha, E-mail: pratibha_sharma@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India)

    2014-01-15

    Core–shell type manganese-doped zinc sulphide nanoparticles ZnS:Mn/ZnS, showing strong absorption of ultraviolet light in the 280–450 nm range and emitting orange-yellow light close to 600 nm, were synthesised for eventual deployment as wavelength down-shifters for solar cells. While most syntheses described in literature employed long reaction times and high reaction/annealing temperatures in excess of 100 °C, this work presents a facile low-temperature wet chemical route. Key synthesis parameters – including zinc to sulphur ratio, manganese doping percentage, reaction sequence and ultrasonication time – were optimised systematically to achieve optimum orange emission intensity. Nanoparticles with average size ∼2.3 nm and showing bright orange emission under UV excitation were ultimately achieved. Various characterisation techniques, namely HRTEM, XRD, ICP, ESR, UV–visible absorption spectrometry and fluorescence spectroscopy, were used to probe the nature of the sample. -- Highlights: • Shell formation achieved by ultrasonic decomposition of zinc–thiourea complex. • Optimal zinc to sulphur ratio in reaction mix was found to be 1:1.2. • Optimal manganese doping percentage was found to be 5.8%. • Addition of cationic precursors to anionic precursors proved to be favourable. • Ultrasonication times exceeding 15 min were detrimental to emission intensity.

  2. Wet-etch sequence optimisation incorporating time dependent chemical maintenance

    NARCIS (Netherlands)

    Kruif, B.J. de

    2015-01-01

    Wafer fabrication is the major cost contributor in semiconductor manufacturing. One of the steps in the fabrication is the removal of exposed layers in an automatic wet-etch station with chemicals. In time, these chemicals get polluted and their effectiveness decreases. Therefore, the chemicals in

  3. Wet chemical preparation of YVO{sub 4}:Eu thin films as red-emitting phosphor layers for fully transparent flat dielectric discharge lamp

    Energy Technology Data Exchange (ETDEWEB)

    Klausch, A. [Institute for Inorganic Chemistry, Dresden University of Technology, Mommsenstr. 6, 01069 Dresden (Germany); Althues, H. [Fraunhofer Institute for Material and Beam Technology Winterbergstr. 28, 01309 Dresden (Germany); Freudenberg, T. [Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany); Kaskel, S., E-mail: Stefan.Kaskel@chemie.tu-dresden.de [Institute for Inorganic Chemistry, Dresden University of Technology, Mommsenstr. 6, 01069 Dresden (Germany)

    2012-04-30

    Highly transparent YVO{sub 4}:Eu thin films were deposited via dip coating of liquid nanoparticle dispersions on glass substrates. Annealing of the nanoparticle layers resulted in restructuring of the material into oriented crystalline films. The crystallinity was confirmed using powder X-ray diffraction. Film thickness was adjusted to 467 nm by multiple deposition. The resulting coatings show > 99% absorbance for wavelength below 300 nm and > 90% transmission in the visible spectral range. Under UV-light excitation a bright red photoluminescence with a quantum efficiency of 20% is observed. A planar, transparent dielectric barrier discharge lamp was constructed using YVO{sub 4}:Eu coated glasses and transparent electrodes made from antimony-doped tin dioxide thin films. - Highlights: Black-Right-Pointing-Pointer Preparation of highly transparent Eu{sup 3+} doped YVO{sub 4} phosphor thin films. Black-Right-Pointing-Pointer Improved crystallinity and optical properties through heat treatment. Black-Right-Pointing-Pointer Red emitting films on glass substrates were combined with antimony tin oxide thin films. Black-Right-Pointing-Pointer Fully transparent, planar gas discharge lamp as prototype for a light emitting window.

  4. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    In a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  5. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  6. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  7. NdFeB nanoparticles prepared by wet-milling

    Energy Technology Data Exchange (ETDEWEB)

    Thielsch, Juliane; Lyubina, Julia; Woodcock, Thomas; Schultz, Ludwig; Gutfleisch, Oliver [IFW Dresden (Germany)

    2010-07-01

    Since the prediction of a giant energy product of textured nanocomposite magnets those materials where believed to be the next generation of permanent magnets. For effective exchange-coupling in such two-phase magnets grain sizes need to be in the range of the domain wall width of the hard magnetic phase. That makes a homogenous phase distribution and a microstructure with nanograins necessary. One option of preparing such materials is the synthesis of magnetic nanoparticles which further could be aligned and compacted to a bulk magnet. For this we performed wet-milling experiments of a NdFeGaNbB alloy. XRD studies revealed that by using a surfactant and a solvent during the high energy ball milling process amorphization sets in later than compared to dry milling experiments under the same conditions. Dynamic Light Scattering investigations showed a Gauss distribution of the particle size with a mean diameter of about 12nm which was also proven by TEM. Magnetic properties were measured with SQUID and showed so far rather poor coercivity values.

  8. Lecithin-based wet chemical precipitation of hydroxyapatite nanoparticles.

    Science.gov (United States)

    Michał, Wojasiński; Ewa, Duszyńska; Tomasz, Ciach

    Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Size distribution for nanoparticles was measured by nanoparticle tracking analysis in NanoSight system. We discuss in details influence of lecithin concentration in reaction system on nHAp-PC morphology, as well as on size distributions and suspendability of nanoparticles. Product exhibits crystalline structure and chemical composition of hydroxyapatite, with visible traces of lecithin. Difference in surfactant amounts results in changes in particles morphology and their average size.

  9. Wet chemical synthesis of LiBaF{sub 3} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vartika S., E-mail: svmoharil@yahoo.com [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Joshi, C.P. [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Moharil, S.V. [Department of Physics, R.T.M. Nagpur University, Nagpur 440 010 (India)

    2013-12-05

    Highlights: •LiBaF{sub 3}:RE{sup 3+} phosphors synthesized by a simple wet chemical method. •Ce{sup 3+} and Tb{sup 3+} emissions observed in as-prepared powders without any thermal treatment. •Intense Eu{sup 2+} emission observed after annealing in reductive atmosphere. -- Abstract: LiBaF{sub 3} has great potential applications as X-ray storage phosphor, slow neutron imaging, scintillator, vacuum ultraviolet (VUV) optical lithography, etc. Conventionally, LiBaF{sub 3} is prepared by solid state reaction between the constituent fluorides. However, the preparation of phase pure material and especially single crystals is rather tricky due to incongruent melting. For the first time, a wet chemical preparation of rare earth activated LiBaF{sub 3} is described here. As precipitated powders containing Ce{sup 3+} or Tb{sup 3+} exhibited characteristic luminescence. For observing Eu{sup 2+} emission, it was necessary to heat the powders in a reductive atmosphere. It is suggested that phosphors prepared by this method may prove useful in applications like OSL, X-ray imaging, etc. which do not require large single crystals.

  10. Wet-chemical passivation of atomically flat and structured silicon substrates for solar cell application

    Science.gov (United States)

    Angermann, H.; Rappich, J.; Korte, L.; Sieber, I.; Conrad, E.; Schmidt, M.; Hübener, K.; Polte, J.; Hauschild, J.

    2008-04-01

    Special sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of differently oriented silicon to prepare very smooth silicon interfaces with excellent electronic properties on mono- and poly-crystalline substrates. Surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and scanning electron microscopy (SEM) investigations were utilised to develop wet-chemical smoothing procedures for atomically flat and structured surfaces, respectively. Hydrogen-termination as well as passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological processing. Compared to conventional pre-treatments, significantly lower micro-roughness and densities of surface states were achieved on mono-crystalline Si(100), on evenly distributed atomic steps, such as on vicinal Si(111), on silicon wafers with randomly distributed upside pyramids, and on poly-crystalline EFG ( Edge-defined Film-fed- Growth) silicon substrates. The recombination loss at a-Si:H/c-Si interfaces prepared on c-Si substrates with randomly distributed upside pyramids was markedly reduced by an optimised wet-chemical smoothing procedure, as determined by PL measurements. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H(n)/c-Si(p)/Al) with textured c-Si substrates the smoothening procedure results in a significant increase of short circuit current Isc, fill factor and efficiency η. The scatter in the cell parameters for measurements on different cells is much narrower, as compared to conventional pre-treatments, indicating more well-defined and reproducible surface conditions prior to a-Si:H emitter deposition and/or a higher stability of the c-Si surface against variations in the a-Si:H deposition conditions.

  11. Characteristics of nanosized zirconia prepared by plasma and chemical technique

    International Nuclear Information System (INIS)

    Kuznetsova, L.; Grabis, J.; Heidemane, G.

    2003-01-01

    The studied preparation method of zirconia using the plasma technique, azeotropic distillation and glycine routes ensure obtaining of nano sized powders with close average particle size but different crystallite size and phase composition. The sinterability of nano sized zirconia particles prepared by plasma technique or wet-chemical methods is similar and depends on the green density of pressed powders, improvement of with can be achieved by using of granulated precursors. (authors)

  12. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  13. A simple wet chemical synthesis and characterization of hydroxyapatite nanorods

    International Nuclear Information System (INIS)

    Liu Yingkai; Hou Dedong; Wang Guanghou

    2004-01-01

    Calcium hydroxyapatite (Ca 5 (PO 4 ) 3 (OH):HAP) nanorods have been synthesized successfully via wet chemical technique at low temperature in the presence of suitable surfactant. The as-made nanorods have a diameter of 50-80 nm and a length of 0.5-1.2 μm. The microstructures and composition are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometer (FT-IR). The formation mechanism of HAP nanorod is discussed in detail. It has been found that nanorods are pure, there is no HAP carbonated HAP. The growth mechanism of HAP nanorods could be explained by a soft template

  14. Trace impurities in coal by wet chemical methods

    International Nuclear Information System (INIS)

    Pollock, E.N.

    1975-01-01

    In determining trace elements in coal by wet chemical methods, conventional atomic absorption spectroscopy (AAS) was used to determine Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, and Pb after dry ashing and acid dissolutions. A graphite furnace accessory was used for the flameless AAS determination of Bi, Se, Sn, Te, Be, Pb, As, Cd, Cr, Sb, and Ge. Mercury can be determined by flameless AAS after oxygen bomb combustion. Arsenic and antimony can be determined as their hydrides by AAS after low temperature ashing. Germanium, tin, bismuth, and tellurium can be determined as their hydrides by AAS after high temperature ashing. Selenium can be determined as its hydride by AAS after a special combustion procedure or after oxygen bomb combustion. Fluorine can be determined by specific ion analysis after oxygen bomb combustion. Boron can be determined colorimetrically. (U.S.)

  15. Preparation and Wetting Behavior of Lyophobic Surface on Zinc Substrate

    Directory of Open Access Journals (Sweden)

    HAN Xiang-xiang

    2018-03-01

    Full Text Available Micro-nano structure on zinc substrate was fabricated through the combination of chemical etching with hydrochloric acid aqueous solution and hydrothermal reaction. After modification with perfluorooctanoic solution, the lyophobic surface was prepared. The phase composition, microstructure, chemical composition, and wettability of the as-obtained surface were investigated by X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectrometer, and contact angle tester. The results show that a layer of ZnO nano-rods grows on the surface of the submicrometer structure, and exhibits good resistance to water impact and stability under the combined action of low surface energy material. When hydrochloric acid concentration is 1.0mol/L and hydrothermal reaction temperature is 95℃, the lyophobic surface possesses the best morphology of ZnO nano-rods. The maximum contact angles of distilled water and peanut oil are 154.65° and 144.65°, respectively, and the sliding angle is less than 10°.

  16. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  17. Preparation of tools for lithographically controlled wetting and soft lithography

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Massmiliano Cavallini, Denis Gentili, Pierpaolo Greco, Francesco Valle & Fabio Biscarini ### Abstract This protocol provides the instructions for designing and fabricating stamping tools with features ranging from nanometer to micrometer scale, including the fabrication using commercial tools such as compact disks or digital video disks. In particular the reported procedures are oriented towards the tools fabrication for lithographically controlled wetting and soft lithograph...

  18. PEG capped CaS nanoparticles synthesized by wet chemical co-precipitation method

    Science.gov (United States)

    Rekha, S.; Anila, E. I.

    2018-04-01

    Calcium sulfide (CaS) nanoparticles capped with polyethyleneglycol (PEG) were synthesized using wet chemical co-precipitation method. The structural and optical properties of the prepared sample were studied by X-ray diffractogram (XRD), transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. The structure of CaS nanoparticles is cubic as demonstrated by the X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEMimage revealed the spherical morphology of the particles with diameter in the range 15-20 nm. The optical band gap of the prepared sample was determined from the DRS and its value was found to be 4.1 eV. The PL studies showed that the relative intensity of the PEG capped CaS nanoparticles was higher than that of uncapped CaS nanoparticles. The presence of various functional groups in the capped samples were examined by Fourier Transform Infrared (FTIR) spectroscopy.

  19. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    International Nuclear Information System (INIS)

    Angermann, Heike

    2014-01-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D it (E), and density D it,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on

  20. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    International Nuclear Information System (INIS)

    Shimpi, Navinchandra G.; Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D.C.; Mishra, Satyendra

    2016-01-01

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  1. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)

    2016-12-30

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  2. Preparation of wet-proofed catalyst for tritium removal

    International Nuclear Information System (INIS)

    Son, S-H.; Lee, G-B.; Song, M-J.

    1995-01-01

    Wetproofed catalysts have been developed for the hydrogen isotopic exchange reaction between hydrogen gas and liquid water. A styrene divinylbenzene copolymer (SDBC) was selected as effective support of the hydrophobic Pt catalyst. Preparation conditions and physical properties of the SDBC were investigated experimentally. The SDBC having the larger pore size, higher surface area and larger particle size were prepared by the particular solvent and stirring speed. The H 2 adsorption isotherm on a supported Pt catalyst was measured and the hydrogen isotopic exchange reaction was verified in the exchange column. (author). 7 refs., 4 tabs., 7 figs

  3. Preparation of wet-proofed catalyst for tritium removal

    Energy Technology Data Exchange (ETDEWEB)

    Son, S-H; Lee, G-B; Song, M-J [Korea Electric Power Corp., Taejon (Korea, Republic of). Research Centre

    1996-12-31

    Wetproofed catalysts have been developed for the hydrogen isotopic exchange reaction between hydrogen gas and liquid water. A styrene divinylbenzene copolymer (SDBC) was selected as effective support of the hydrophobic Pt catalyst. Preparation conditions and physical properties of the SDBC were investigated experimentally. The SDBC having the larger pore size, higher surface area and larger particle size were prepared by the particular solvent and stirring speed. The H{sub 2} adsorption isotherm on a supported Pt catalyst was measured and the hydrogen isotopic exchange reaction was verified in the exchange column. (author). 7 refs., 4 tabs., 7 figs.

  4. Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Mou; Mathews, N. R. [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico); Sanchez-Mora, E.; Pal, U. [Instituto de Física, BUAP (Mexico); Paraguay-Delgado, F. [Centro de Investigación en Materiales Avanzados (CIMAV), Departamento de Materiales Nanoestructurados (Mexico); Mathew, X., E-mail: xm@ier.unam.mx [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico)

    2015-07-15

    CuS nanoparticles (NPs) of few nanometers in size were prepared by a wet chemical method. The structural, compositional, and optical properties of the NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, micro Raman and Fourier transform infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, and UV–Vis diffuse reflectance spectroscopy. The XRD pattern proved the presence of hexagonal phase of CuS particles which was further supported by Raman spectrum. The estimated band gap energy of 2.05 eV for the slightly sulfur-rich CuS NPs is relatively larger than that of bulk CuS (1.85 eV), indicating the small size effect. As-prepared NPs showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light. The surface-bound OH{sup −} ions at the CuS nanostructures help adsorb MB molecules facilitating their degradation process under visible light illumination. The studies presented in this paper suggest that the synthesized CuS NPs are promising, efficient, stable, and visible-light-sensitive photocatalyst for the remediation of wastewater polluted by chemically stable azo dyes such as MB.

  5. Field emission characteristics of SnO2/CNT composite prepared by microwave assisted wet impregnation

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-01-01

    Full Text Available SnO2/CNT composites were prepared by microwave assisted wet impregnation at 60 °C. The process was optimized by varying the microwave power and reaction time. Raman analysis showed the typical features of the rutile phase of as-synthesized SnO2...

  6. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  7. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

    Science.gov (United States)

    Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

    2018-03-01

    We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Wet chemical synthesis of nickel supported on alumina catalysts

    International Nuclear Information System (INIS)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

    2016-01-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

  9. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

    2014-09-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

  10. WetA bridges cellular and chemical development in Aspergillus flavus.

    Directory of Open Access Journals (Sweden)

    Ming-Yueh Wu

    Full Text Available Bridging cellular reproduction and survival is essential for all life forms. Aspergillus fungi primarily reproduce by forming asexual spores called conidia, whose formation and maturation is governed by the central genetic regulatory circuit BrlA→AbaA→WetA. Here, we report that WetA is a multi-functional regulator that couples spore differentiation and survival, and governs proper chemical development in Aspergillus flavus. The deletion of wetA results in the formation of conidia with defective cell walls and no intra-cellular trehalose, leading to reduced stress tolerance, a rapid loss of viability, and disintegration of spores. WetA is also required for normal vegetative growth, hyphal branching, and production of aflatoxins. Targeted and genome-wide expression analyses reveal that WetA exerts feedback control of brlA and that 5,700 genes show altered mRNA levels in the mutant conidia. Functional category analyses of differentially expressed genes in ΔwetA RNA-seq data indicate that WetA contributes to spore integrity and maturity by properly regulating the metabolic pathways of trehalose, chitin, α-(1,3-glucan, β-(1,3-glucan, melanin, hydrophobins, and secondary metabolism more generally. Moreover, 160 genes predicted to encode transcription factors are differentially expressed by the absence of wetA, suggesting that WetA may play a global regulatory role in conidial development. Collectively, we present a comprehensive model for developmental control that bridges spore differentiation and survival in A. flavus.

  11. Preparation of SnO2 Nanoparticles by Two Different Wet Chemistry Methods

    International Nuclear Information System (INIS)

    Ridha, N.J.; Akrajas Ali Umar; Muhammad Yahya; Muhammad Mat Salleh; Mohamad Hafizuddin Jumali

    2011-01-01

    The objective of this project is to prepare SnO 2 nanoparticles by two different wet chemistry methods namely sol gel and direct growth methods. The XRD results indicated that both samples are single phase SnO 2 . The FE-SEM micrographs displayed that SnO 2 nanoparticles prepared in first method exhibited a round shape with particle size around 15 nm while the second method produced SnO 2 nano rod with length and width of 570 nm and 55 nm respectively. Energy gap values for SnO 2 nanospheres and nano rods were 4.38 and 4.34 eV respectively. (author)

  12. Surface passivation by Al2O3 and a-SiNx: H films deposited on wet-chemically conditioned Si surfaces

    NARCIS (Netherlands)

    Bordihn, S.; Mertens, V.; Engelhart, P.; Kersten, K.; Mandoc, M.M.; Müller, J.W.; Kessels, W.M.M.

    2012-01-01

    The surface passivation of p- and n-type silicon by different chemically grown SiO2 films (prepared by HNO3, H2SO4/H2O2 and HCl/H2O2 treatments) was investigated after PECVD of a-SiNx:H and ALD of Al2O3 capping films. The wet chemically grown SiO2 films were compared to thermally grown SiO2 and the

  13. A wet-chemical approach to perovskite and fluorite-type nanoceramics: synthesis and processing

    NARCIS (Netherlands)

    Veldhuis, Sjoerd

    2015-01-01

    In thesis the low-temperature, wet-chemical approach to various functional inorganic oxide materials is described. The main focus of this research is to control the material’s synthesis from liquid precursor to metal oxide powder or thin film; while understanding its formation mechanism. In

  14. Determination of chemical oxygen demand (COD) using an alternative wet chemical method free of mercury and dichromate.

    Science.gov (United States)

    Kolb, Marit; Bahadir, Müfit; Teichgräber, Burkhard

    2017-10-01

    Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R 2  = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Preparation and study of poly vinyl alcohol/hyperbranched polylysine fluorescence fibers via wet spinning

    Science.gov (United States)

    Lu, Hongwei; Zou, Liming; Xu, Yongjing; Sun, Hong; Li, Yan Vivian

    2018-02-01

    A simple method of using wet spinning was found effective in the preparation of photoluminescent poly vinyl alcohol (PVA)/hyperbranched polylysine (HBPL) fibers. The photoluminescence of the PVA/HBPL fibers was significantly uniform and the unique uniformity was obtained by controlling the mass ratio of PVA to HBPL in aqueous solutions used in the wet spinning process. The high solubility of HBPL in water make it feasible to well control in the mass ratio of PVA to HBPL, which facilitated the formation of a unique PVA/HBPL mixture, resulting in the fabrication of homogeneous PVA composite fluorescence fibers. The composite fibers exhibit good mechanical, and thermal properties that make the PVA/HBPL fluorescent fibers a great material potentially used in fluorescence applications including optics, imaging and detection.

  16. Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes

    International Nuclear Information System (INIS)

    Chaghi, R; Cervera, C; Aït-Kaci, H; Grech, P; Rodriguez, J B; Christol, P

    2009-01-01

    In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current–voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 Ω cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air

  17. Wet-chemical passivation of InAs: toward surfaces with high stability and low toxicity.

    Science.gov (United States)

    Jewett, Scott A; Ivanisevic, Albena

    2012-09-18

    In a variety of applications where the electronic and optical characteristics of traditional, siliconbased materials are inadequate, recently researchers have employed semiconductors made from combinations of group III and V elements such as InAs. InAs has a narrow band gap and very high electron mobility in the near-surface region, which makes it an attractive material for high performance transistors, optical applications, and chemical sensing. However, silicon-based materials remain the top semiconductors of choice for biological applications, in part because of their relatively low toxicity. In contrast to silicon, InAs forms an unstable oxide layer under ambient conditions, which can corrode over time and leach toxic indium and arsenic components. To make InAs more attractive for biological applications, researchers have investigated passivation, chemical and electronic stabilization, of the surface by adlayer adsorption. Because of the simplicity, low cost, and flexibility in the type of passivating molecule used, many researchers are currently exploring wet-chemical methods of passivation. This Account summarizes much of the recent work on the chemical passivation of InAs with a particular focus on the chemical stability of the surface and prevention of oxide regrowth. We review the various methods of surface preparation and discuss how crystal orientation affects the chemical properties of the surface. The correct etching of InAs is critical as researchers prepare the surface for subsequent adlayer adsorption. HCl etchants combined with a postetch annealing step allow the tuning of the chemical properties in the near-surface region to either arsenic- or indium-rich environments. Bromine etchants create indium-rich surfaces and do not require annealing after etching; however, bromine etchants are harsh and potentially destructive to the surface. The simultaneous use of NH(4)OH etchants with passivating molecules prevents contact with ambient air that can

  18. Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

    1999-01-01

    Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

  19. Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

    Science.gov (United States)

    Gao, Huiying; Li, Zhiyong; Zhao, Peng

    2018-03-01

    Nanosized α-Al2O3 powders were prepared with AlCl3ṡ6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline α-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical α-Al2O3 powders without hard agglomeration and with particle size in the range of 20-40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

  20. Moessbauer study of Mn-Zn and Mn ferrites prepared by wet method

    International Nuclear Information System (INIS)

    Michalk, C.

    1985-01-01

    Moessbauer spectroscopy was employed to study Mn-Zn ferrites before and after low-temperature annealing. The unannealed Mn-Zn ferrite prepared by a wet method and also the sintered material after annealing at 400 deg C in air show the presence of paramagnetic clusters. These findings are explained as being due to nonrandom ordering of Fe 3+ and Zn 2+ ions caused by local charge compensation in the neighbourhood of cation vacancies. A change of cation distribution after annealing at relatively low temperatures was observed. 10 refs., 3 figs. (author)

  1. Preparation and characterisation of Co–Fe–Ni–M-Si–B (M = Zr, Ti) amorphous powders by wet mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Neamţu, B.V., E-mail: Bogdan.Neamtu@stm.utcluj.ro [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105, Muncii Avenue, 400641, Cluj-Napoca (Romania); Chicinaş, H.F.; Marinca, T.F. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105, Muncii Avenue, 400641, Cluj-Napoca (Romania); Isnard, O. [Université Grenoble Alpes, Institut NEEL, F-38042, Grenoble (France); CNRS, Institut NEEL, 25 rue des martyrs, BP166, F-38042, Grenoble (France); Chicinaş, I. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 103-105, Muncii Avenue, 400641, Cluj-Napoca (Romania)

    2016-07-15

    Co-based amorphous alloys were prepared via wet mechanical alloying process starting from elemental powders. The reference alloy Co{sub 70}Fe{sub 4}Ni{sub 2}Si{sub 15}B{sub 9} (at. %) as well as the alloys derived from this composition by the substitution of 5 at.% of Zr or Ti for Si or B (Co{sub 70}Fe{sub 4}Ni{sub 2}Si{sub 15}B{sub 4}Zr{sub 5}, Co{sub 70}Fe{sub 4}Ni{sub 2}Si{sub 15}B{sub 4}Ti{sub 5}, Co{sub 70}Fe{sub 4}Ni{sub 2}Si{sub 10}B{sub 9}Zr{sub 5} and Co{sub 70}Fe{sub 4}Ni{sub 2}Si{sub 10}B{sub 9}Ti{sub 5}) are obtained in amorphous state, according to X-ray diffraction (XRD) investigation, after 40 h of milling. The calculated amount of amorphous fraction reaches 99% after 40 h of milling. The largest increase of the crystallisation temperature was induced by the substitution of Zr or Ti for Si while, regardless of the type of substitution, an important increase of the Curie temperature of the alloy was obtained. A Co-based solid solution, with Co{sub 2}Si and Co{sub 2}B phases, result after crystallisation of the amorphous alloys as proved by XRD investigations. Saturation magnetisation of the alloys decreases upon increasing milling time, however it remains larger than the saturation magnetisation of the reference alloy. This was discussed in correlation with the specificity of the wet mechanical alloying process and the influence of the chemical bonding between Co and metalloids atoms over the magnetic moment of Co. - Highlights: • Co–Fe–Ni–M-Si–B (M = Zr, Ti) amorphous powders were prepared by wet MA. • Amorphisation of the alloy is reached after 40 h of wet MA for any composition. • Magnetisation decrease upon increasing milling time. • Substituting 5% Zr/Ti for Si increases significantly the alloy's thermal stability. • Substitution of 5 at. % Zr/Ti for Si increases the saturation magnetisation by 20%.

  2. Influence of wet chemical cleaning on quantum efficiency of GaN photocathode

    International Nuclear Information System (INIS)

    Wang Xiao-Hui; Gao Pin; Wang Hong-Gang; Li Biao; Chang Ben-Kang

    2013-01-01

    GaN samples 1–3 are cleaned by a 2:2:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%) to de-ionized water; hydrochloric acid (37%); or a 4:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%). The samples are activated by Cs/O after the same annealing process. X-ray photoelectron spectroscopy after the different ways of wet chemical cleaning shows: sample 1 has the largest proportion of Ga, N, and O among the three samples, while its C content is the lowest. After activation the quantum efficiency curves show sample 1 has the best photocathode performance. We think the wet chemical cleaning method is a process which will mainly remove C contamination. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  3. Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

    Science.gov (United States)

    Li, Wei; Cochell, Thomas; Manthiram, Arumugam

    2013-01-01

    Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

  4. Fabrication of high quality GaN nanopillar arrays by dry and wet chemical etching

    OpenAIRE

    Paramanik, Dipak; Motayed, Abhishek; King, Matthew; Ha, Jong-Yoon; Kryluk, Sergi; Davydov, Albert V.; Talin, Alec

    2013-01-01

    We study strain relaxation and surface damage of GaN nanopillar arrays fabricated using inductively coupled plasma (ICP) etching and post etch wet chemical treatment. We controlled the shape and surface damage of such nanopillar structures through selection of etching parameters. We compared different substrate temperatures and different chlorine-based etch chemistries to fabricate high quality GaN nanopillars. Room temperature photoluminescence and Raman scattering measurements were carried ...

  5. Nitride-based Schottky diodes and HFETs fabricated by photo-enhanced chemical wet etching

    International Nuclear Information System (INIS)

    Su, Y.K.; Chang, S.J.; Kuan, T.M.; Ko, C.H.; Webb, J.B.; Lan, W.H.; Cherng, Y.T.; Chen, S.C.

    2004-01-01

    Photo-enhanced chemical (PEC) wet etching technology was used to etch GaN and AlGaN epitaxial layers. It was found that the maximum etch rates were 510, 1960, 300, and 0 nm/mm for GaN, Al 0.175 Ga 0.825 N, Al 0.23 Ga 0.77 N, and Al 0.4 Ga 0.6 N, respectively. It was also found that we could achieve a high Al 0.175 Ga 0.825 N to GaN etch rate ratio of 12.6. Nitride-based Schottky diodes and heterostructure field effect transistors (HFETs) were also fabricated by PEC wet etching. It was found that we could achieve a saturated I D larger than 850 mA/mm and a maximum g m about 163 mS/mm from PEC wet etched HFET with a 0.5 μm gate length. Compared with dry etched devices, the leakage currents observed from the PEC wet etched devices were also found to be smaller

  6. CT colonography in a Korean population with a high residue diet: Comparison between wet and dry preparations

    International Nuclear Information System (INIS)

    Kim, S.H.; Choi, B.I.; Han, J.K.; Lee, J.M.; Eun, H.W.; Lee, J.Y.; Lee, K.H.; Han, C.J.; Choi, Y.H.; Shin, K.-S.

    2006-01-01

    AIM: To compare wet and dry preparation methods for computed tomography colonography (CTC) in terms of preparation quality, interpretation time, and diagnostic performance for polyp detection in a population with a high residue diet. MATERIALS AND METHODS: Eighty-six patients were divided into two groups. Group 1 (n=24) received a wet preparation of 4 l polyethylene glycol (PEG) solution, and group 2 (n=62) received a dry preparation of phosphor-soda. Abnormal findings, including polyps, and the time required to interpret the CTC images in both groups were documented by a radiologist. CTC findings were compared to those of colonoscopy as a reference standard. Two radiologists evaluated the quality of CTC with regard to residual fluid, faeces, and colonic distension using a four-point scale in consensus. Statistical differences for residual fluid, faeces, distensibility on CTC, and interpretation time between the two groups were analysed. The diagnostic performance of CTC in both groups was also compared. RESULTS: One-hundred and ninety polyps in 70 patients were identified using colonoscopy. Regarding the quality of images produced the wet preparation was significantly better than the dry preparation (p 0.05). CONCLUSION: In a population with a high-residue diet, CTC with wet preparation can be interpreted in a time-efficient manner and is comparable with CTC with dry preparation

  7. Effects of Dry-Milling and Wet-Milling on Chemical, Physical and Gelatinization Properties of Rice Flour

    Directory of Open Access Journals (Sweden)

    Jitranut Leewatchararongjaroen

    2016-09-01

    Full Text Available Rice flour from nine varieties, subjected to dry- and wet-milling processes, was determined for its physical and chemical properties. The results revealed that milling method had an effect on properties of flour. Wet-milling process resulted in flour with significantly lower protein and ash contents and higher carbohydrate content. Wet-milled flour also tended to have lower lipid content and higher amylose content. In addition, wet-milled rice flour contained granules with smaller average size compared to dry-milled samples. Swelling power at 90 °C of wet-milled samples was higher while solubility was significantly lower than those of dry-milled flour. Dry milling process caused the destruction of the crystalline structure and yielded flour with lower crystallinity compared to wet-milling process, which resulted in significantly lower gelatinization enthalpy.

  8. Quantification of normal vaginal constituents using a new wet preparation technique.

    Science.gov (United States)

    Fowler, R Stuart

    2012-10-01

    This study aimed to evaluate a new method for preparing vaginal wet preparations to enable quantification of cells and lactobacilli. The current nonstandardized technique allows for a variable amount of vaginal fluid collected, diluted by a variable amount of saline/KOH, and no quantification of constituents. The vaginal fluids from 100 randomly selected women without vulvovaginitis symptoms presenting to the author's practice at Mayo Clinic underwent analysis by the quantification technique. Women were excluded if they were younger than 18 years, had antibiotics within the past 2 months, currently on their period, had placed anything in the vagina for the past 24 hours, used Depo-Provera, or were lactating. All the wet preparations were made by mixing the natural vaginal fluids with 3 mL of sterile normal saline. Spinal diluting fluid was added to the saline preparation. The saline and KOH mixtures were injected into separate wells of KOVA Glasstic Grid Slide and analyzed with a phase-contrast microscope at 40× and 60×. The concentration of leukocytes, lactobacilli, and squamous cells and the degree of maturation of the majority (>50%) of squamous cells were assessed, and it was determined whether there was excessive non-lactobacilli bacteria (EB) as evident by clumps of bacteria in the background fluid and speckling on the squamous cells. The 3 most common patterns to occur were as follows: First, 51% (95% confidence interval [CI] = 41%-60%) of the total specimens had abundant lactobacilli, no leukocytes, more than 50% fully maturated squamous cells, and no EB. Second, 22% (95% CI = 14%-32%) of the total specimens had low lactobacilli counts, no leukocytes, more than 50% undermaturated squamous cells, and no EB. Third, 12% (95% CI = 6%-20%) of the total specimens had abundant lactobacilli, leukocytes, more than 50% fully maturated squamous cells, and no EB. It is imperative to be able to objectively quantify normal vaginal secretion constituents so that (1) the

  9. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    International Nuclear Information System (INIS)

    Kakati, A; Maji, D; Das, S

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

  10. Wet-chemical approach for the cell-adhesive modification of polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Gabriel, Matthias; Dahm, Manfred; Vahl, Christian-F

    2011-01-01

    Polytetrafluoroethylene (PTFE), a frequently utilized polymer for the fabrication of synthetic vascular grafts, was surface-modified by means of a wet-chemical process. The inherently non-cell-adhesive polymer does not support cellular attachment, a prerequisite for the endothelialization of luminal surface grafts in small diameter applications. To impart the material with cell-adhesive properties a treatment with sodium-naphthalene provided a basis for the subsequent immobilization of the adhesion promoting RGD-peptide using a hydroxy- and amine-reactive crosslinker. Successful conjugation was shown with cell culture experiments which demonstrated excellent endothelial cell growth on the modified surfaces.

  11. Direct synthesis of nanocrystalline oxide powders by wet-chemical techniques

    Directory of Open Access Journals (Sweden)

    Vladimir V. Srdić

    2010-09-01

    Full Text Available In a recent period there is a great need for increasing the knowledge of tailoring the innovative procedures for the synthesis of electroceramic nanopowders and materials with improved quality for specific application. In order to produce electroceramics with desirable microstructure and properties, synthesis of stoichiometric, ultra-fine and agglomerate free powders with narrow size distributions is one of the most important steps. Within this scope, in the present paper we summarize our recent results on direct synthesis of some important perovskites and ferrites nanopowders by wet-chemical techniques.

  12. Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

    Science.gov (United States)

    Zhang, Wei; Jia, Baoping; Wang, Qiuze; Dionysiou, Dionysois

    2015-05-01

    Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment.

  13. Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

    International Nuclear Information System (INIS)

    Zhang, Wei; Jia, Baoping; Wang, Qiuze; Dionysiou, Dionysois

    2015-01-01

    Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO 2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO 2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO 2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO 2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment

  14. Bottom-Up, Wet Chemical Technique for the Continuous Synthesis of Inorganic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Annika Betke

    2014-01-01

    Full Text Available Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO, magnetite (Fe3O4, as well as brushite (CaHPO4·2H2O, particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.

  15. Wet chemical deposition of single crystalline epitaxial manganite thin films with atomically flat surface

    International Nuclear Information System (INIS)

    Mishra, Amita; Dutta, Anirban; Samaddar, Sayanti; Gupta, Anjan K.

    2013-01-01

    We report the wet chemical deposition of single crystalline epitaxial thin films of the colossal magneto-resistive manganite La 0.67 Sr 0.33 MnO 3 on the lattice-matched (001)-face of a La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 substrate. Topographic images of these films taken with a scanning tunneling microscope show atomically flat terraces separated by steps of monatomic height. The resistivity of these films shows an insulator-metal transition at 310 K, nearly coincident with the Curie temperature of 340 K, found from magnetization measurements. The films show a magnetoresistance of 7% at 300 K and 1.2 T. Their saturation magnetization value at low temperatures is consistent with that of the bulk. - Highlights: ► Wet chemical deposition of La 0.67 Sr 0.33 MnO 3 (LSMO) on a lattice-matched substrate. ► Single crystalline epitaxial LSMO films obtained. ► Flat terraces separated by monatomic steps observed by scanning tunneling microscope

  16. Optimization of wet lay-up conditions for steam generators hydrazine chemical treatment

    International Nuclear Information System (INIS)

    Long, A.; Organista, M.; Brun, C.; Combrade, P.

    2002-01-01

    Since a long time, hydrazine is used as a chemical agent to prevent corrosion of unalloyed steels. This is a conventional treatment widely used by nuclear power plant operators. But its application in SG lay-up at French nuclear power plants has, however, lead to some drawbacks. Effluent releases: Due to regulation relative to release of hydrazine and alkaline chemical compounds, some plant operators limit the concentrations of reagents to levels that could lead to insufficient protection of materials. Safety hazards associated with SG nitrogen blanketing: Prohibiting use of nitrogen blankets for SG wet lay-up due to associated safety hazards could likewise jeopardize corrosion protection at normally specified hydrazine levels. As the exact limits of hydrazine action against corrosion during SG lay-up are not well known, it is sometimes difficult to evaluate the risk associated to low dosage of N 2 H 4 . In order to answer to these problems, Framatome ANP (France) decided to carry out a test program aimed to determine the limit conditions for use of hydrazine in a wet lay-up environment. (authors)

  17. Latent structure analysis in the pharmaceutical process of tablets prepared by wet granulation.

    Science.gov (United States)

    Uehara, Naoto; Hayashi, Yoshihiro; Mochida, Hiroshi; Otoguro, Saori; Onuki, Yoshinori; Obata, Yasuko; Takayama, Kozo

    2016-01-01

    Granule characteristics are some of the important intermediate qualities that determine tablet properties. However, the relationships between granule and tablet characteristics are poorly understood. The aim of this study was to elucidate relationships among formulation factors, granule characteristics, and tablet properties using a non-linear response surface method (RSM) incorporating a thin-plate spline interpolation (RSM-S) and a Bayesian network (BN). Tablets containing lactose (Lac), cornstarch (CS), and microcrystalline cellulose (MCC) were prepared by wet granulation. Ten formulations were prepared by an extreme vertices design. The angle of repose (Y 1 ), compressibility (Y 2 ), cohesion force (Y 3 ), internal friction angle (Y 4 ), and mean particle size (Y 5 ) were measured as granule characteristics. Tensile strength (TS) and disintegration time (DT) were measured as tablet properties. RSM-S results showed that TS increased with increasing amounts of MCC and Lac. DT decreased with increasing amounts of MCC and CS. The optimal BN models were predicted using four evaluation indices -Y 3 was shown to be the most important factor for TS, whereas Y 2 , Y 3 , and Y 4 were relatively important for predicting DT. Moreover, tablets with excellent tablet properties (i.e. high TS and low DT) were produced by relatively high Y 1 , low Y 2 , high Y 3 , high Y 4 , and middle Y 5 values, and resulted from the middle of MCC, middle-to-low CS, low Lac, and middle-to-low magnesium stearate (Mg-St) amounts. The RSM-S and BN techniques are useful for revealing complex relationships among formulation factors, granule characteristics, and tablet properties.

  18. Preparation, characterization, and evaluation of azoxystrobin nanosuspension produced by wet media milling

    Science.gov (United States)

    Yao, Junwei; Cui, Bo; Zhao, Xiang; Wang, Yan; Zeng, Zhanghua; Sun, Changjiao; Yang, Dongsheng; Liu, Guoqiang; Gao, Jinming; Cui, Haixin

    2018-04-01

    To improve the bioavailability of the poorly water-soluble fungicide, an azoxystrobin nanosuspension was prepared by the wet media milling method. Due to their reduced mean particle size and polydispersity index, 1-Dodecanesulfonic acid sodium salt and polyvinylpyrrolidone K30 were selected from six conventional surfactants, the content only accounting for 15% of the active compound. The mean particle size, polydispersity index, and ζ potential of the nanosuspension were determined to be 238.1 ± 1.5 nm, 0.17 ± 0.02 and - 31.8 ± 0.3 mV, respectively. The lyophilized nanosuspension mainly retained crystalline state, with only a little amorphous content as determined by powder X-ray diffraction. Compared to conventional fungicide formulations, the nanosuspension presented an increased retention volume and a reduced contact angle, indicating enhanced wettability and adhesion. In addition, the azoxystrobin nanosuspension showed the highest antifungal activity, with a medial lethal concentration of 1.4243 μg/mL against Fusarium oxysporum. In optical micrographs, hyphal deformations of thinner and intertwined hyphae were detected in the exposed group. Compared to the control group, the total soluble protein content, superoxide dismutase, and catalase activities were initially increased and then decreased with prolonged exposure time. The azoxystrobin nanosuspension reduced the defensive antioxidant capability of Fusarium oxysporum and resulted in the generation of excessive reactive oxygen species. This study provides a novel method for preparing nanosuspension formulation of poorly soluble antifungal agents to enhance the biological activity and decrease the negative environmental impact.

  19. Combined wet-chemical process to synthesize 65PMN-35PT nanosized powders

    International Nuclear Information System (INIS)

    Santos, Luis P.S.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2004-01-01

    Columbite MgNb 2 O 6 precursors were synthesized by a wet-chemical method by means of the dissolution of Nb 2 O 5 .5H 2 O and magnesium carbonate in a solution of oxalic acid. Pure 65PMN-35PT powders could be obtained by the columbite method with the use of the partial oxalate and oxidant peroxo methods. Powders were characterized by X-ray diffraction and FT-Raman spectroscopy showing that pure 65PMN-35PT are obtained when the powders are calcined up to 800 deg. C, without any trace of Pb-Nb pyrochlore. Cubic Pb 1,86 Mg 0.24 Nb 1.76 O 6.5 pyrochlore phase is formed by lead loss in the powders calcined at 900 deg. C and higher temperatures as undoubtedly characterized by Raman spectroscopy

  20. Washing of gel particles in wet chemical manufacture of reactor fuel particles

    International Nuclear Information System (INIS)

    Ringel, H.

    1980-07-01

    In the manufacture of HTR fuel particles and particles of fertile material by wet chemical methods, the ammonium nitrate formed during the precipitation reaction must be washed out of the gel particles. This washing process has been investigated theoretically and experimentally. A counter-current washer has been developed which in particular takes account of the aspects of refabrication - such as compact construction and minimum waste. A counter-current washing column of 17 mm internal diameter and 640 mm length gives to gel particle throughput of 0.65 1/h. The volume ratio of wash water to gel particles is 5, and the residual nitrate concentration in the particles is 7 x 10 -3 mols of NO - 3 /1. (orig.) [de

  1. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  2. Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process.

    Science.gov (United States)

    Sun, Qunhui; Bi, Wu; Fuller, Thomas F; Ding, Yong; Deng, Yulin

    2009-06-17

    In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4-aminothiophenol (4-ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm(-2) , was synthesized. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, H. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany)], E-mail: angermann@hmi.de; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany); Huebener, K.; Hauschild, J. [Freie Universitaet Berlin, FB Physik, Arnimallee 14, 14195 Berlin (Germany)

    2008-08-30

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D{sub it}(E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency.

  4. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    International Nuclear Information System (INIS)

    Angermann, H.; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M.; Huebener, K.; Hauschild, J.

    2008-01-01

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D it (E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency

  5. Simulation of the evolution of fused silica's surface defect during wet chemical etching

    Science.gov (United States)

    Liu, Taixiang; Yang, Ke; Li, Heyang; Yan, Lianghong; Yuan, Xiaodong; Yan, Hongwei

    2017-08-01

    Large high-power-laser facility is the basis for achieving inertial confinement fusion, one of whose missions is to make fusion energy usable in the near future. In the facility, fused silica optics plays an irreplaceable role to conduct extremely high-intensity laser to fusion capsule. But the surface defect of fused silica is a major obstacle limiting the output power of the large laser facility and likely resulting in the failure of ignition. To mitigate, or event to remove the surface defect, wet chemical etching has been developed as a practical way. However, how the surface defect evolves during wet chemical etching is still not clearly known so far. To address this problem, in this work, the three-dimensional model of surface defect is built and finite difference time domain (FDTD) method is developed to simulate the evolution of surface defect during etching. From the simulation, it is found that the surface defect will get smooth and result in the improvement of surface quality of fused silica after etching. Comparatively, surface defects (e.g. micro-crack, scratch, series of pinholes, etc.) of a typical fused silica at different etching time are experimentally measured. It can be seen that the simulation result agrees well with the result of experiment, indicating the FDTD method is valid for investigating the evolution of surface defect during etching. With the finding of FDTD simulation, one can optimize the treatment process of fused silica in practical etching or even to make the initial characterization of surface defect traceable.

  6. Preparation of TiC/W core–shell structured powders by one-step activation and chemical reduction process

    International Nuclear Information System (INIS)

    Ding, Xiao-Yu; Luo, Lai-Ma; Huang, Li-Mei; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2015-01-01

    Highlights: • A novel wet chemical method was used to prepare TiC/W core–shell structure powders. • TiC nanoparticles were well-encapsulated by W shells. • TiC phase was present in the interior of tungsten grains. - Abstract: In the present study, one-step activation and chemical reduction process as a novel wet-chemical route was performed for the preparation of TiC/W core–shell structured ultra-fine powders. The XRD, FE-SEM, TEM and EDS results demonstrated that the as-synthesized powders are of high purity and uniform with a diameter of approximately 500 nm. It is also found that the TiC nanoparticles were well-encapsulated by W shells. Such a unique process suggests a new method for preparing X/W (X refers the water-insoluble nanoparticles) core–shell nanoparticles with different cores

  7. Microbes and associated soluble and volatile chemicals on periodically wet household surfaces.

    Science.gov (United States)

    Adams, Rachel I; Lymperopoulou, Despoina S; Misztal, Pawel K; De Cassia Pessotti, Rita; Behie, Scott W; Tian, Yilin; Goldstein, Allen H; Lindow, Steven E; Nazaroff, William W; Taylor, John W; Traxler, Matt F; Bruns, Thomas D

    2017-09-26

    Microorganisms influence the chemical milieu of their environment, and chemical metabolites can affect ecological processes. In built environments, where people spend the majority of their time, very little is known about how surface-borne microorganisms influence the chemistry of the indoor spaces. Here, we applied multidisciplinary approaches to investigate aspects of chemical microbiology in a house. We characterized the microbial and chemical composition of two common and frequently wet surfaces in a residential setting: kitchen sink and bathroom shower. Microbial communities were studied using culture-dependent and independent techniques, including targeting RNA for amplicon sequencing. Volatile and soluble chemicals from paired samples were analyzed using state-of-the-art techniques to explore the links between the observed microbiota and chemical exudates. Microbial analysis revealed a rich biological presence on the surfaces exposed in kitchen sinks and bathroom shower stalls. Microbial composition, matched for DNA and RNA targets, varied by surface type and sampling period. Bacteria were found to have an average of 25× more gene copies than fungi. Biomass estimates based on qPCR were well correlated with measured total volatile organic compound (VOC) emissions. Abundant VOCs included products associated with fatty acid production. Molecular networking revealed a diversity of surface-borne compounds that likely originate from microbes and from household products. Microbes played a role in structuring the chemical profiles on and emitted from kitchen sinks and shower stalls. Microbial VOCs (mVOCs) were predominately associated with the processing of fatty acids. The mVOC composition may be more stable than that of microbial communities, which can show temporal and spatial variation in their responses to changing environmental conditions. The mVOC output from microbial metabolism on kitchen sinks and bathroom showers should be apparent through careful

  8. PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

    Directory of Open Access Journals (Sweden)

    W. Luepcke

    2017-12-01

    Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

  9. Investigation of microstructure and mechanical properties of phosphocalcic bone substitute using the chemical wet method

    Science.gov (United States)

    Alimi, Latifa; Bahloul, Lynda; Azzi, Afef; Guerfi, Souad; Ismail, Fadhel; Chaoui, Kamel

    2018-05-01

    Selection of calcium phosphate base materials in reconstructive bone surgery is justified by the surprising similarities in chemical compositions with human bones. The closest to natural apatite material is the hydroxyapatite (HAp) which has a chemical composition based on calcium and phosphate (Ca10(PO4)6(OH)2). In this study, HAp is synthesized using the wet precipitation method from hydrated calcium chloride (CaCl2,12H2O) and di-sodium hydrogen phosphate di-hydrate (HNa2PO4,2H2O). The powder is calcinated at 900°C and 1200°C in order to compare with sintered condition at 1150°C. Vickers microhardness tests and X-ray diffraction analyzes are used for the characterization of the crystalline material. Mechanical properties (Hv, σe, σr, and KC) and the degree of crystallinity (Xc) are discussed according to heat treatment temperatures. Results indicate that heat treating the powder at 1200°C increased crystallinity up to 72%. At the same time, microhardness increased with temperature and even outmatched the sintered case at 1150°C. Fracture toughness is ameliorated with increasing heat treatment temperature by more than two folds.

  10. Analysis of Wetting and Contact Angle Hysteresis on Chemically Patterned Surfaces

    KAUST Repository

    Xu, Xianmin; Wang, Xiaoping

    2011-01-01

    Wetting and contact angle hysteresis on chemically patterned surfaces in two dimensionsare analyzed from a stationary phase-field model for immiscible two phase fluids. We first study the sharp-interface limit of the model by the method of matched asymptotic expansions. We then justify the results rigorously by the γ-convergence theory for the related variational problem and study the properties of the limiting minimizers. The results also provide a clear geometric picture of the equilibrium configuration of the interface. This enables us to explicitly calculate the total surface energy for the two phase systems on chemically patterned surfaces with simple geometries, namely the two phase flow in a channel and the drop spreading. By considering the quasi-staticmotion of the interface described by the change of volume (or volume fraction), we can follow the change-of-energy landscape which also reveals the mechanism for the stick-slip motion of the interface and contact angle hysteresis on the chemically patterned surfaces. As the interface passes throughpatterned surfaces, we observe not only stick-slip of the interface and switching of the contact angles but also the hysteresis of contact point and contact angle. Furthermore, as the size of the patternde creases to zero, the stick-slip becomes weaker but the hysteresis becomes stronger in the sense that one observes either the advancing contact angle or the receding contact angle (when the interface ismoving in the opposite direction) without the switching in between. © 2011 Society for Industrial and Applied Mathematics.

  11. [Responsibilities of enterprises introducing new dangerous chemical substances and preparations].

    Science.gov (United States)

    Cieśla, Jacek; Majka, Jerzy

    2004-01-01

    The paper reviews the responsibilities of producers, importers and distributors set in a new Act of January 2001 on chemical substances and preparations (Off. J. 2001, No. 11, item 84, with subsequent amendments). This Act together with executive provisions is aimed at harmonizing Polish legislation with EU requirements. The Act sets conditions, restriction and bans of production placing on the market and use of chemical substances and preparations in order to protect human health and environment against their harmful effects. The Act together with a number of executive provisions render those who introduce dangerous chemicals and chemical preparations, including distributors responsible for: classification and labelling of dangerous chemical substances and preparations; possessing, making available and up-dating safety data sheets; supplying packages containing certain dangerous substances with child-proof fastenings; notifying the Inspector for Chemical Substances and Preparations about placing a dangerous preparation on the market; notifying the Inspector about a new substance and conducting required studies; being properly qualified to handle dangerous substances. The Act strictly defines the term "placing a substance or a preparation on the market"--it means making a substance or a preparation available to third parties on the territory of The Republic of Poland, territories of the Member States of the European Union or the territory of Iceland, Liechtenstein and Norway, unless the Act provides otherwise; it also means introduction of a substance or a preparation from outside of the territory referred to above on the customs territory of The Republic of Poland, or that of the member states of the European Union and other states listed above. In addition, some of the responsibilities defined by the provisions of the law on chemical substances and preparations are also applicable to handling of biocidals, which are classified as dangerous substances. The Act

  12. Comparison of wet-only and bulk deposition at Chiang Mai (Thailand) based on rainwater chemical composition

    Science.gov (United States)

    Chantara, Somporn; Chunsuk, Nawarut

    The chemical composition of 122 rainwater samples collected daily from bulk and wet-only collectors in a sub-urban area of Chiang Mai (Thailand) during August 2005-July 2006 has been analyzed and compared to assess usability of a cheaper and less complex bulk collector over a sophisticated wet-only collector. Statistical analysis was performed on log-transformed daily rain amount and depositions of major ions for each collector type. The analysis of variance (ANOVA) test revealed that the amount of rainfall collected from a rain gauge, bulk collector and wet-only collector showed no significant difference ( ∝=0.05). The volume weight mean electro-conductivity (EC) values of bulk and wet-only samples were 0.69 and 0.65 mS/m, respectively. The average pH of the samples from both types of collectors was 5.5. Scatter plots between log-transformed depositions of specific ions obtained from bulk and wet-only samples showed high correlation ( r>0.91). Means of log-transformed bulk deposition were 14% (Na + and K +), 13% (Mg 2+), 7% (Ca 2+), 4% (NO 3-), 3% (SO 42- and Cl -) and 2% (NH 4+) higher than that of wet-only deposition. However, multivariate analysis of variance (MANOVA) revealed that ion depositions obtained from bulk and wet-only collectors were not significantly different ( ∝=0.05). Therefore, it was concluded that a bulk collector can be used instead of a wet-only collector in a sub-urban area.

  13. CuO nanostructures on copper foil by a simple wet chemical route at room temperature

    International Nuclear Information System (INIS)

    Jana, S.; Das, S.; Das, N.S.; Chattopadhyay, K.K.

    2010-01-01

    Uniform CuO nanostructures have been synthesized on copper foil substrates by oxidation of Cu in alkaline condition by a simple wet chemical route at room temperature. By controlling the alkaline condition (pH value) different CuO nanostructures like nanoneedles, self-assembled nanoflowers and staking of flake-like structures were achieved. The phase formation and the composition of the films were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. X-ray photoelectron spectroscopic studies indicated that the samples were composed of CuO. The morphologies of the films were investigated by scanning electron microscopy. A possible growth mechanism is also proposed here. Band gap energies of the nanostructures were determined from the optical reflectance spectra. The different CuO nanostructures showed good electron field emission properties with turn-on fields in the range 6-11.3 V μm -1 . The field emission current was significantly affected by the morphologies of the CuO films.

  14. Bioceramics synthesis of hydroxyapatite from red snapper fish scales biowaste using wet chemical precipitation route

    Science.gov (United States)

    Ulfyana, D.; Anugroho, F.; Sumarlan, S. H.; Wibisono, Y.

    2018-03-01

    Fish scales biowaste contain high collagens and calcium phosphates, therefore have considerable potential as raw material for value-added biomaterial such as hydroxyapatite (HAp). HAp is the main constituent component of hard tissue such as bone and teeth in the human body and is known as bioceramic materials. In this work, wet chemical precipitation method was used to syntesize HAp from Red Snapper Fish (Lutjanus campechanus) Scales. Two variations of calcination temperatures of 600°C (FHAp1) and 800°C (FHAp2) were conducted for 5 hours. The results showed calcium content from biowaste of red snapper fish scale was 83.62%. FTIR result shows that PO4 3-, OH-, and CO3 2- functional groups presence as indicates the formation of HAp. XRD result showed the degree of crystallinity for FHAp1 and FHAp2 were 75.52% and 79.20%, respectively. The degree of crystallinity is in accordance with ISO 13779-2:2000 standard in which the minimum degree of crystallinity of hydroxyapatite used for biomedical materials is 45%. Finally, Particle Size Analyzer (PSA) results show that the particle size distribution is evenly distributed, with the size of micro-scale hydroxyapatite particles, ranging from 5.76 μm to 132.64 μm.

  15. Wet chemical passivation of YBa2Cu3O(7-x)

    Science.gov (United States)

    Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

    1990-01-01

    Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, which result in the formation of native compounds known to have little or no reactivity to water. Suitable native compounds include CuI, BaSO4, CuS, Cu2S, YF3, and the oxalates. Formation of surface layers in which these nonreactive native compounds are major constituents is verified with X-ray photoelectron spectroscopy (XPS) measurements on YBa2Cu3O(7-x) films treated with dilute solutions of HI, H2SO4, Na2S, HF, or H2C2O4. No significant changes are observed in the XPS spectra when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide and fluoride films show evidence of reaction with water. X-ray diffraction measurements show that the superconducting phase is absent in the sulfide film, but is unaffected by the oxalate and sulfate treatments.

  16. Tailoring Novel PTFE Surface Properties: Promoting Cell Adhesion and Antifouling Properties via a Wet Chemical Approach.

    Science.gov (United States)

    Gabriel, Matthias; Niederer, Kerstin; Becker, Marc; Raynaud, Christophe Michel; Vahl, Christian-Friedrich; Frey, Holger

    2016-05-18

    Many biomaterials used for tissue engineering applications lack cell-adhesiveness and, in addition, are prone to nonspecific adsorption of proteins. This is especially important for blood-contacting devices such as vascular grafts and valves where appropriate surface properties should inhibit the initial attachment of platelets and promote endothelial cell colonization. As a consequence, the long-term outcome of the implants would be improved and the need for anticoagulation therapy could be reduced or even abolished. Polytetrafluoroethylene (PTFE), a frequently used polymer for various medical applications, was wet-chemically activated and subsequently modified by grafting the endothelial cell (EC) specific peptide arginine-glutamic acid-aspartic acid-valine (REDV) using a bifunctional polyethylene glycol (PEG)-spacer (known to reduce platelet and nonspecific protein adhesion). Modified and control surfaces were both evaluated in terms of EC adhesion, colonization, and the attachment of platelets. In addition, samples underwent bacterial challenges. The results strongly suggested that PEG-mediated peptide immobilization renders PTFE an excellent substrate for cellular growth while simultaneously endowing the material with antifouling properties.

  17. Zintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable Composition.

    Science.gov (United States)

    Bentlohner, Manuel M; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Müller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Fässler, Thomas F

    2016-02-12

    [Ge9](4-) Zintl clusters are used as soluble germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable composition. The method is based on the assembly and oxidation of [Ge9 ](4-) clusters in a template mold using SiCl4 , GeCl4 , and PCl3 leading to Si and P-containing Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray analysis. [Ge9](4-) clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. (1)H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9](4-). Subsequent annealing leads to crystalline Ge. As an example for wet-chemical synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphology of the films with regular volume porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae.

    Science.gov (United States)

    Im, Hanjin; Kim, Bora; Lee, Jae W

    2015-10-01

    This work addresses an unprecedented way of co-producing biodiesel (FAEE) and valuable chemicals of ethyl levulinate (EL), ethyl formate (EF) and diethyl ether (DEE) from wet in situ transesterification of microalgae. EL, EF, and DEE were significantly produced up to 23.1%, 10.3%, and 52.1% of the maximum FAEE mass with the FAEE yield higher than 90% at 125 °C. Experiments to elucidate a detailed route of EL and EF synthesis were fulfilled and it was found that its main route to the production of EL and EF was the acid hydrolysis of algal cells and esterification with ethanol. To investigate the effect of reaction variables on the products yields, comprehensive experiments were carried out with varying temperatures, solvent and alcohol volumes, moisture contents and catalyst amounts. Coproduction of DEE, EL, EF and FAEE can contribute to elevating the economic feasibility of microalgae-based biodiesel supply chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Physical, sensory and chemical properties of bread prepared from ...

    African Journals Online (AJOL)

    Physical, sensory and chemical properties of bread prepared from wheat and ... Different levels (0, 1, 2 and 3% w/w) of cissus gum powder was added to ... flours for bread making where 100% wheat bread without cissus gum served as control. ... serve as a gluten substitute in preparing acceptable wheat bread substituted ...

  20. Chemical Preparation Laboratory IND Candidate Compounds.

    Science.gov (United States)

    1986-01-21

    and final products unreported in the chemical literature were fully characterized by elemental and spectral analyses. 3 V% TABLE OF CONTENTS Page I...resulting crystalline material was filtered and washed with water to yield 2.0 g. An additional 0.2 g of the product was recovered from the above filtrate... mercaptopurine (Tri-C- acetvlthioinosine) (3): To a well stirred mixture of 2 (93.0 g, 0.236 mol) and pyridine (3570 mL), phosphorus pentasulfide (220.0 g, 0.49

  1. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2014-07-01

    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Comparative study of telmisartan tablets prepared via the wet granulation method and pritor™ prepared using the spray-drying method.

    Science.gov (United States)

    Park, Junsung; Park, Hee Jun; Cho, Wonkyung; Cha, Kwang-Ho; Yeon, Wonki; Kim, Min-Soo; Kim, Jeong-Soo; Hwang, Sung-Joo

    2011-03-01

    The wet granulation method was successfully used to manufacture amorphous telmisartan tablets (CNU) for comparison with the spray-drying method, used for Pritor™. Drug crystallinity in the tablet was characterized using differential scanning calorimetry and powder X-ray diffraction, and pharmaceutical properties of the tablets such as hardness, friability, water absorption, and in vitro dissolution in pH 1.2, 4.0, 6.8 and 7.5 were characterized. Especially with regard to the water absorption feature, the CNU tablets showed better performance by maintaining their original structures and by absorbing less water. Since both Pritor™ and CNU tablets had similar physical properties of crystallinity, hardness, friability, and > 50 f(2) value in an in vitro dissolution study, the bioequivalence of CNU tablets should be analyzed in a future in vivo study. Therefore, telmisartan tablets can be produced using a more economical and easier method than that used to produce Pritor™ tablets.

  3. Size- and Shape-Dependent Antibacterial Studies of Silver Nanoparticles Synthesized by Wet Chemical Routes

    Directory of Open Access Journals (Sweden)

    Muhammad Akram Raza

    2016-04-01

    Full Text Available Silver nanoparticles (AgNPs of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM, UV-visible spectroscopy (UV-VIS, and X-ray diffraction (XRD techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm. The characteristic surface plasmon resonance (SPR peaks of different spherical silver colloids occurring in the wavelength range of 397 to 504 nm, whereas triangular particles showed two peaks, first at 392 nm and second at 789 nm as measured by UV-VIS. The XRD spectra of the prepared samples indicated the face-centered cubic crystalline structure of metallic AgNPs. The in vitro antibacterial properties of all synthesized AgNPs against two types of Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli were examined by Kirby–Bauer disk diffusion susceptibility method. It was noticed that the smallest-sized spherical AgNPs demonstrated a better antibacterial activity against both bacterial strains as compared to the triangular and larger spherical shaped AgNPs.

  4. Collection and preparation of wet and dry stream-sediment samples

    International Nuclear Information System (INIS)

    Puchlik, K.

    1977-03-01

    Lawrence Livermore Laboratory is responsible for the Hydrogeochemistry and Stream Sediment Reconnaissance (HSSR) program for uranium in the seven far western states. The work thus far has concentrated on the arid to semi-arid regions of the West and this paper discusses the collection and preparation of sediment samples in the Basin and Range province. The sample collection and preparation procedures described here may not be applicable to other parts of the far western states or other areas. These procedures also differ somewhat from those used by the other three laboratories involved in the HSSR program

  5. Compaction of Chemically Prepared Amorphous Fe-B nanoparticles

    DEFF Research Database (Denmark)

    Hendriksen, P.V.; Bødker, Franz; Mørup, Steen

    1997-01-01

    We report on attempts to compact chemically prepared amorphous iron-boron particles. The praticles have a size of about 100 nm and are pyrophoric. We have made a special die for uniaxial pressing in which the compaction can be performed at elevated temperature without exposing the powder to air...

  6. Use of the direct compression aid Ludiflash(®) for the preparation of pellets via wet extrusion/spheronization.

    Science.gov (United States)

    Roblegg, Eva; Schrank, Simone; Griesbacher, Martin; Radl, Stefan; Zimmer, Andreas; Khinast, Johannes

    2011-10-01

    Conventional solid oral dosage forms are unsuitable for children due to problems associated with swallowing and unpleasant taste. Additionally, the limit of tablets lays in the patient adapted dosing. Therefore, the suitability of Ludiflash(®), a direct compression aid for orally disintegrating tablets, was investigated for the preparation of individually dosable pellets. Micropellets consisting of Ludiflash(®) and small amounts of microcrystalline cellulose were prepared via the wet extrusion/spheronization technique. Paracetamol and ibuprofen were applied as model drugs. The obtained pellets were characterized with respect to drug release and disintegration characteristics, mechanical properties, as well as size and shape. Drug loading was possible up to 30% for ibuprofen and even up to 50% for paracetamol. Higher ibuprofen loadings resulted in considerably slowed drug release and higher paracetamol contents yielded in non-spherical pellets. In vitro release studies revealed that more than 80% of the drug was released within 30 and 60 min for paracetamol and ibuprofen, respectively. Drug release rates were highly influenced by the pellet disintegration behavior. Investigations of the release mechanism using the Korsemeyer-Peppas approach suggested Super Case II drug transport for all paracetamol formulations and anomalous drug transport for most ibuprofen formulations. All pellets exhibited a low porosity and friability, as well as a sufficiently high tensile strength, which was significantly influenced by the type of model drug. Ludiflash(®) can be applied as main excipient for the preparation of individually dosable pellets combining fast drug release and a high mechanical stability.

  7. Evolution of the magnetic properties of Co10Cu90 nanoparticles prepared by wet chemistry with thermal annealing.

    Science.gov (United States)

    García, I; Echeberria, J; Kakazei, G N; Golub, V O; Saliuk, O Y; Ilyn, M; Guslienko, K Y; González, J M

    2012-09-01

    Nanoparticles of Co10Cu90 alloy have been prepared by sonochemical wet method. According to transmission electron microscopy, bimetallic particles with typical diameter of 50-100 nm consisting of nanocrystallites with average diameter of 15-20 nm were obtained. The samples were annealed at 300 degrees C and 450 degrees C. Zero field cooled and field cooled temperature dependences of magnetization in the temperature range of 5-400 K at 50 Oe, as well as magnetization hysteresis loops at 15, 100 and 305 K were measured by vibrating sample magnetometry. Presence of antiferromagnetic phase, most probably of the oxide Co3O4, was observed in as-prepared sample. The lowest coercivity was found for the CoCu sample annealed at-300 degrees C, whereas for as prepared sample and the one annealed at 450 degrees C it was significantly higher. The samples were additionally probed by continuous wave ferromagnetic resonance at room, temperature using a standard X-band electron spin resonance spectrometer. A good correspondence between evolution of the coercivity and the microwave resonance fields with annealing temperature was observed.

  8. Hydrolysis of solubilized hemicellulose derived from wet-oxidized wheat straw by a mixture of commercial fungal enzyme preparations

    Energy Technology Data Exchange (ETDEWEB)

    Skammelsen Schmidt, Anette; Thomsen, Alle Belinda; Woidemann, Anders [Risoe National Lab. (Denmark); Tenkanen, Maija [VTT Biotechnology and Food Research (Finland)

    1998-04-01

    The enzymatic hydrolysis of the solubilized hemicellulose fraction from wet-oxidized wheat straw was investigated for quantification purposes. An optimal hydrolysis depends on factors such as composition of the applied enzyme mixture and the hydrolysis conditions (enzyme loading, hydrolysis time, pH-value, and temperature). A concentrated enzyme mixture was used in this study prepared at VTT Biotechnology and Food Research, Finland, by mixing four commercial enzyme preparations. No distinctive pH-value and temperature optima were identified after a prolonged incubation of 24 hours. By reducing the hydrolysis time to 2 hours a temperature optimum was found at 50 deg. C, where a pH-value higher than 5.2 resulted in reduced activity. An enzyme-substrate-volume-ratio of 0.042, a pH-value of 5.0, and a temperature of 50 deg. C were chosen as the best hydrolysis conditions due to an improved monosaccharide yield. The hydrolysis time was chosen to be 24 hours to ensure equilibrium and total quantification. Even under the best hydrolysis conditions, the overall sugar yield from the enzymatic hydrolysis was only 85% of that of the optimal acid hydrolysis. The glucose yield were approximately the same for the two types of hydrolyses, probably due to the high cellulase activity in the VTT-enzyme mixture. For xylose and arabinose the enzymatic hydrolysis yielded only 80% of that of the acid hydrolysis. As the pentoses existed mainly as complex polymers their degradation required many different enzymes, some of which might be missing from the VTT-enzyme mixture. Furthermore, the removal of side-choins from the xylan backbone during the wet-oxidation pretreatment process might enable the hemicellulosic polymers to interact and precipitate, hence, reducing the enzymatic digestibility of the hemicellulose. (au) 8 tabs., 10 ills., 65 refs.

  9. Wet-Chemical Synthesis of Enhanced-Thermopower Bi1 -xSbx Nanowire Composites for Solid-State Active Cooling of Electronics

    Science.gov (United States)

    Vandaele, K.; He, Bin; Van Der Voort, P.; De Buysser, K.; Heremans, J. P.

    2018-02-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. In 1993, Hicks and Dresselhaus [Thermoelectric figure of merit of a one-dimensional conductor, Phys. Rev. B 47, 16631 (1993)., 10.1103/PhysRevB.47.16631] suggested that Bi nanowires could result in values of the thermoelectric figure of merit z T >1 . The Dresselhaus group also calculated a ternary phase diagram for Bi1 -xSbx nanowires as a function of x and wire diameter. This manuscript reports a wet-chemical method to synthesize Bi1 -xSbx -silica nanowire composites. Resistivity, Hall electron concentration, electron mobility, Seebeck and Nernst coefficients, and thermal conductivity of composites are measured and compared to bulk polycrystalline Bi1 -xSbx samples prepared either by ingot casting or by the same wet chemistry but without nanostructuring. A clear increase of the thermopower in 20-nm Bi94Sb6 -silica is reported when compared to bulk samples, and the values are among the highest found in the literature from 300 to 380 K, even though the electron concentration is higher than in the bulk. This suggests that consistent with theory, size quantization is responsible for the thermopower increase.

  10. Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

    Science.gov (United States)

    Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

    2018-02-01

    We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

  11. A simple wet chemical method for the determination of cation stoichiometry of YBa2Cu3O7-d

    International Nuclear Information System (INIS)

    Sahasranaman, S.; Premila, M.; Sreedharan, O.M.

    1996-01-01

    A comprehensive wet chemical procedure for the rapid analysis of yttrium, barium and copper ions in dilute HNO 3 medium has been developed to facilitate a precise and accurate determination of cation non-stoichiometry in high temperature ceramic superconducting materials Y 1±x Ba 2±y Cu 3±z O 7-d . The ease of analysis for copper by electrogravimetry and of yttrium and barium by a complexometric titration of the same aliquot against complexone III using arsenazo I as the indicator under appropriate pH has been demonstrated with the help of individual standard solutions and with synthetic mixtures. (author)

  12. Morphologies and wetting properties of copper film with 3D porous micro-nano hierarchical structure prepared by electrochemical deposition

    International Nuclear Information System (INIS)

    Wang, Hongbin; Wang, Ning; Hang, Tao; Li, Ming

    2016-01-01

    Highlights: • A 3D porous micro-nano hierarchical structure Cu films were prepared. • The evolution of morphology and wettability with deposition time was reported. • The effects of EDA on the microscopic morphology were revealed. • A high contact angle of 162.1° was measured when deposition time is 5 s. • The mechanism of super-hydrophobicity was illustrated by two classical models. - Abstract: Three-dimensional porous micro-nano hierarchical structure Cu films were prepared by electrochemical deposition with the Hydrogen bubble dynamic template. The morphologies of the deposited films characterized by Scanning Electronic Microscopy (SEM) exhibit a porous micro-nano hierarchical structure, which consists of three levels in different size scales, namely the honeycomb-like microstructure, the dendritic substructure and the nano particles. Besides, the factors which influenced the microscopic morphology were studied, including the deposition time and the additive Ethylene diamine. By measuring the water contact angle, the porous copper films were found to be super-hydrophobic. The maximum of the contact angles could reach as high as 162.1°. An empirical correlation between morphologies and wetting properties was revealed for the first time. The pore diameter increased simultaneously with the deposition time while the contact angle decreased. The mechanism was illustrated by two classical models. Such super-hydrophobic three-dimensional hierarchical micro-nano structure is expected to have practical application in industry.

  13. Temperature dependence of morphology, structural and optical properties of ZnS nanostructures synthesized by wet chemical route

    International Nuclear Information System (INIS)

    Navaneethan, M.; Archana, J.; Nisha, K.D.; Hayakawa, Y.; Ponnusamy, S.; Muthamizhchelvan, C.

    2010-01-01

    Research highlights: → ZnS nanoparticles and nanorods have been synthesized by wet chemical route. → Higher annealing temperature influenced the change in morphology due to aggregation of the nanoparticles. → The temperature dependent optical properties were investigated. → Absorption edge of nanoparticles (295 nm) and nanorods (326 nm) were shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect. → ZnS nanoparticles exhibit high photoluminescence intensity than that of ZnS nanorods annealed at 180 o C. - Abstract: ZnS nanostructures have been synthesized by simple wet chemical route and annealed at two different temperatures of 50 o C and 180 o C. From the measurements of transmission electron microscopy and contact-mode atomic force microscopy, it is found that annealed temperature changes the morphology from nanoparticles to nanorods. The optical properties of the synthesized ZnS nanomaterial have been characterized by UV-visible absorption spectroscopy and photoluminescence spectroscopy. The structural and elemental analyses were carried out by powder X-ray diffraction pattern and energy dispersive X-ray absorption spectroscopy, respectively. Absorption edge of the nanoparticles (295 nm) and nanorods (326 nm) was shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect.

  14. Fabrication of Cu{sub 2}S nanoneedles by self-assembly of nanoparticles via simple wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za; Coombes, Matthew J.; Neethling, Johannes H.; Westraadt, Johan E.

    2014-03-15

    Highlights: • An inexpensive wet chemical method was used at room temperature to grow Cu{sub 2}S. • Growth of Cu{sub 2}S nanostructures influences by the Cl{sup −} ion concentration. • Thioglycerol and Cl{sup −} ions are used as a blend capping agents. • Cu{sub 2}S nanoneedles were formed via self-assembly of nanoparticles. • We can propose a growth model for Cu{sub 2}S nanoneedles based on our observations. -- Abstract: Cu{sub 2}S nanoneedles, fabricated by self-assembly of Cu{sub 2}S nanoparticles via wet chemical method are investigated. Crystallinity and surface morphologies of the as-grown needles are examined using X-ray diffraction and scanning and transmission electron microscopy. It is observed that the nanoparticle formation is controlled by the blend concentration of capping agents, thioglycerol, added during the synthesis and the Cl{sup −} ions delivered by the CuCl source. The likely reasons for the elongated structure of the nanoparticle self-assembly are also discussed.

  15. Wet oxidative degradation of cellulosic wastes 5- chemical and thermal properties of the final waste forms

    International Nuclear Information System (INIS)

    Eskander, S.B.; Saleh, H.M.

    2002-01-01

    In this study, the residual solution arising from the wet oxidative degradation of solid organic cellulosic materials, as one of the component of radioactive solid wastes, using hydrogen peroxide as oxidant. Were incorporated into ordinary Portland cement matrix. Leaching as well as thermal characterizations of the final solidified waste forms were evaluated to meet the final disposal requirements. Factors, such as the amount of the residual solution incorporated, types of leachant. Release of different radionuclides and freezing-thaw treatment, that may affect the leaching characterization. Were studied systematically from the data obtained, it was found that the final solid waste from containing 35% residual solution in tap water is higher than that in ground water or sea water. Based on the data obtained from thermal analysis, it could be concluded that incorporating the residual solution form the wet oxidative degradation of cellulosic materials has no negative effect on the hydration of cement materials and consequently on the thermal stability of the final solid waste from during the disposal process

  16. Investigation of the Factors Influencing Volatile Chemical Fate During Steady-state Accretion on Wet-growing Hail

    Science.gov (United States)

    Michael, R. A.; Stuart, A. L.

    2007-12-01

    Phase partitioning during freezing affects the transport and distribution of volatile chemical species in convective clouds. This consequently can have impacts on tropospheric chemistry, air quality, pollutant deposition, and climate change. Here, we discuss the development, evaluation, and application of a mechanistic model for the study and prediction of volatile chemical partitioning during steady-state hailstone growth. The model estimates the fraction of a chemical species retained in a two-phase freezing hailstone. It is based upon mass rate balances over water and solute for accretion under wet-growth conditions. Expressions for the calculation of model components, including the rates of super-cooled drop collection, shedding, evaporation, and hail growth were developed and implemented based on available cloud microphysics literature. Solute fate calculations assume equilibrium partitioning at air-liquid and liquid-ice interfaces. Currently, we are testing the model by performing mass balance calculations, sensitivity analyses, and comparison to available experimental data. Application of the model will improve understanding of the effects of cloud conditions and chemical properties on the fate of dissolved chemical species during hail growth.

  17. The contact angle of wetting of the solid phase of soil before and after chemical modification

    Directory of Open Access Journals (Sweden)

    Tyugai Zemfira

    2015-07-01

    Full Text Available Wettability of soil affects a wide variety of processes including infiltration, preferential flow and surface runoff. Wettability of surface is usually expressed in terms of contact angle (CA measurement. If the CA between liquid and solid surface is less than 90°, the surface is called hydrophilic, otherwise the surface is called hydrophobic. If the CA of water droplet on hydrophilic surface is in a range of 0-30° this surface is called superhydrophilic. In case of superhydrophobic surfaces the CA exceeds 150° that means that these surfaces are extremely difficult to wet. CA of wetting of mineral soil particles depends on the overlying organic and iron compounds. The object of study is a sample of the humus-accumulative horizon of typical chernozem (Kursk, Russia and two samples (horizons A1, B2 of red ferrallitic soils (Fr. Norfolk, NE Oceania. The soil samples were analyzed for organic carbon, forms of non-silicate iron and hydrophobic-hydrophilic composition of humic substances. CA of wetting was determined in the intact samples and after removal of organic matter (H2O2 treatment, amorphous and crystallized forms of iron. Static contact angles were determined with the sessile drop method using a digital goniometer (Drop Shape Analysis System, DSA100, Krüss GmbH, Hamburg, Germany. The contact angle was calculated by the Young–Laplace method (fitting of Young–Laplace equation to the drop shape. The measurements were repeated 10-15 times for every sample. Oxidation of organic matter (H2O2 treatment causes an increase in the values of CA of wetting (in chernozem from 9.3 to 28,0-29.5º, in ferrallitic soil from 18.0 − 27.3 to 22.4 − 33.4º. CA remained constant for chernozem and slightly decreased in the case of ferrallitic soil, when the removal of amorphous and crystallized forms of iron was performed on samples pretreated with H2O2. CA increase occurs after successive removal of nonsilicate forms of iron from soil samples of

  18. Analysis of the Si(111) surface prepared in chemical vapor ambient for subsequent III-V heteroepitaxy

    International Nuclear Information System (INIS)

    Zhao, W.; Steidl, M.; Paszuk, A.; Brückner, S.; Dobrich, A.; Supplie, O.; Kleinschmidt, P.; Hannappel, T.

    2017-01-01

    Highlights: • We investigate the Si(111) surface prepared in CVD ambient at 1000 °C in 950 mbar H_2. • UHV-based XPS, LEED, STM and FTIR as well as ambient AFM are applied. • After processing the Si(111) surface is free of contamination and atomically flat. • The surface exhibits a (1 × 1) reconstruction and monohydride termination. • Wet-chemical pretreatment and homoepitaxy are required for a regular step structure. - Abstract: For well-defined heteroepitaxial growth of III-V epilayers on Si(111) substrates the atomic structure of the silicon surface is an essential element. Here, we study the preparation of the Si(111) surface in H_2-based chemical vapor ambient as well as its atomic structure after contamination-free transfer to ultrahigh vacuum (UHV). Applying complementary UHV-based techniques, we derive a complete picture of the atomic surface structure and its chemical composition. X-ray photoelectron spectroscopy measurements after high-temperature annealing confirm a Si surface free of any traces of oxygen or other impurities. The annealing in H_2 ambient leads to a monohydride surface termination, as verified by Fourier-transform infrared spectroscopy. Scanning tunneling microscopy confirms a well ordered, atomically smooth surface, which is (1 × 1) reconstructed, in agreement with low energy electron diffraction patterns. Atomic force microscopy reveals a significant influence of homoepitaxy and wet-chemical pretreatment on the surface morphology. Our findings show that wet-chemical pretreatment followed by high-temperature annealing leads to contamination-free, atomically flat Si(111) surfaces, which are ideally suited for subsequent III-V heteroepitaxy.

  19. Analysis of the Si(111) surface prepared in chemical vapor ambient for subsequent III-V heteroepitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, W.; Steidl, M.; Paszuk, A. [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Brückner, S. [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Helmholtz-Zentrum Berlin, Institut für Solare Brennstoffe, 14109 Berlin (Germany); Dobrich, A. [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Supplie, O. [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Helmholtz-Zentrum Berlin, Institut für Solare Brennstoffe, 14109 Berlin (Germany); Kleinschmidt, P. [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Hannappel, T., E-mail: thomas.hannappel@tu-ilmenau.de [Technische Universität Ilmenau, Institut für Physik, 98693 Ilmenau (Germany); Helmholtz-Zentrum Berlin, Institut für Solare Brennstoffe, 14109 Berlin (Germany)

    2017-01-15

    Highlights: • We investigate the Si(111) surface prepared in CVD ambient at 1000 °C in 950 mbar H{sub 2}. • UHV-based XPS, LEED, STM and FTIR as well as ambient AFM are applied. • After processing the Si(111) surface is free of contamination and atomically flat. • The surface exhibits a (1 × 1) reconstruction and monohydride termination. • Wet-chemical pretreatment and homoepitaxy are required for a regular step structure. - Abstract: For well-defined heteroepitaxial growth of III-V epilayers on Si(111) substrates the atomic structure of the silicon surface is an essential element. Here, we study the preparation of the Si(111) surface in H{sub 2}-based chemical vapor ambient as well as its atomic structure after contamination-free transfer to ultrahigh vacuum (UHV). Applying complementary UHV-based techniques, we derive a complete picture of the atomic surface structure and its chemical composition. X-ray photoelectron spectroscopy measurements after high-temperature annealing confirm a Si surface free of any traces of oxygen or other impurities. The annealing in H{sub 2} ambient leads to a monohydride surface termination, as verified by Fourier-transform infrared spectroscopy. Scanning tunneling microscopy confirms a well ordered, atomically smooth surface, which is (1 × 1) reconstructed, in agreement with low energy electron diffraction patterns. Atomic force microscopy reveals a significant influence of homoepitaxy and wet-chemical pretreatment on the surface morphology. Our findings show that wet-chemical pretreatment followed by high-temperature annealing leads to contamination-free, atomically flat Si(111) surfaces, which are ideally suited for subsequent III-V heteroepitaxy.

  20. Green wet chemical route to synthesize capped CdSe quantum dots

    Indian Academy of Sciences (India)

    In the present work, we report green synthesis of tartaric acid (TA) and triethanolamine (TEA) capped ... CdSe quantum dots; chemical bath deposition; capping; green chemistry; nanomaterials. 1. .... at high concentration of nanoparticles.

  1. Ruthenium and Platinum Catalysts Supported on Ce, Zr, Pr-O Mixed Oxides Prepared by Soft Chemistry for Acetic Acid Wet Air Oxidation

    Czech Academy of Sciences Publication Activity Database

    Mikulová, Jana; Rossignol, S.; Barbier Jr., J.; Mesnard, D.; Kappenstein, C.; Duprez, D.

    2007-01-01

    Roč. 72, 1-2 (2007), s. 1-10 ISSN 0926-3373 Institutional research plan: CEZ:AV0Z40720504 Keywords : sol-gel * catalytic wet air oxidation * acetic acid Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 4.651, year: 2007

  2. Synthesis of BaTiO3 nanoparticles from TiO2-coated BaCO3 particles derived using a wet-chemical method

    Directory of Open Access Journals (Sweden)

    Yuuki Mochizuki

    2014-03-01

    Full Text Available BaCO3 particles coated with amorphous TiO2 precursor are prepared by a wet chemical method to produce BaTiO3 nanoparticles at low temperatures. Subsequently, we investigate the formation behavior of BaTiO3 particles and the particle growth behavior when the precursor is subjected to heat treatment. The state of the amorphous TiO2 coating on the surface of BaCO3 particles depends on the concentration of NH4HCO3, and the optimum concentration is found to be in the range 0.5–1.0 M. Thermogravimetric curves of the BaCO3 particles coated with the TiO2 precursor, prepared from BaCO3 particles of various sizes, show BaTiO3 formation occurring mainly at 550–650 °C in the case of fine BaCO3 particles. However, as evidenced from the curves, the temperature of formation of BaTiO3 shifts to higher values with an increase in the size of the BaCO3 particles. The average particle size of single phase BaTiO3 at heat-treatment temperature of 650–900 °C is observed to be in the range 60–250 nm.

  3. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R J; Johnson, Jr, A B; Lund, A L; Gilbert, E R [and others

    1996-07-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl{sub x}, UAl{sub x}-Al and U{sub 3}O{sub 8}-Al cermets, U-5% fissium, UMo, UZrH{sub x}, UErZrH, UO{sub 2}-stainless steel cermet, and U{sub 3}O{sub 8}-stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified.

  4. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Guenther, R.J.; Johnson, A.B. Jr.; Lund, A.L.; Gilbert, E.R.

    1994-11-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl x , UAl x -Al and U 3 O 8 -Al cermets, U-5% fissium, UMo, UZrH x , UErZrH, UO 2 -stainless steel cermet, and U 3 O 8 -stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified

  5. Influence of Air Pollution on Chemical Quality of Wet Atmospheric Deposition: a Case Study in Urmia, Iran

    Directory of Open Access Journals (Sweden)

    Yaghoub Hajizadeh

    2017-10-01

    Full Text Available Increased combustion of fossil fuel owing to the energy requirement is a main cause of air pollution throughout the world. Atmospheric precipitation is considered as a major water resource for indoor, municipal, industrial and agricultural uses. This study was aimed to evaluate the effect of air pollution on chemical quality of rain and snow in Urmia, a city in northwest of Iran. Sampling was performed during the wet seasons from October to March at six sampling stations in different locations of the city. Acidity, alkalinity, NO3- , SO42-, Cl- and pH contents of the collected samples were analyzed. All samples showed a pH value of more than 6.8, and lower acidity than alkalinity, therefore, the precipitations were not acidic. Maximum concentrations of SO42- and NO3- in the samples were 5 and 8.8mg/L, respectively. Chloride was varied from 1 to 11.5 mg/L with the highest measures observing in autumn. According to the results, concentrations of the analyzed parameters in wet precipitations in Urmia were within the natural ranges except chloride ions, which was higher than its common level in the atmosphere. This phenomenon may be the result of desert dusts which transfers by wind from the west border to Iran. ‎

  6. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    Science.gov (United States)

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Bär, Marcus; Sadewasser, Sascha

    2014-12-01

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for "realistic" surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is - apart from a slight change in surface composition - identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  7. chemical and physical comparative study of the effect of wet and dry ...

    African Journals Online (AJOL)

    eobe

    The clay content of the raw clay which was 48 wt% was improved to 73 wt%. The clay content of the ... refractories and wide spectrum of ceramics [4, 5] in several industries. ... physicochemical properties, which can be determined by chemical ...

  8. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T., E-mail: aruna_reddy@nal.res.in; Basu, Bharathibai J.

    2013-07-15

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  9. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    International Nuclear Information System (INIS)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T.; Basu, Bharathibai J.

    2013-01-01

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  10. Formation of hydrogen-related traps in electron-irradiated n-type silicon by wet chemical etching

    International Nuclear Information System (INIS)

    Tokuda, Yutaka; Shimada, Hitoshi

    1998-01-01

    Interaction of hydrogen atoms and vacancy-related defects in 10 MeV electron-irradiated n-type silicon has been studied by deep-level transient spectroscopy. Hydrogen has been incorporated into electron-irradiated n-type silicon by wet chemical etching. The reduction of the concentration of the vacancy-oxygen pair and divacancy occurs by the incorporation of hydrogen, while the formation of the NH1 electron trap (E c - 0.31 eV) is observed. Further decrease of the concentration of the vacancy-oxygen pair and further increase of the concentration of the NH1 trap are observed upon subsequent below-band-gap light illumination. It is suggested that the trap NH1 is tentatively ascribed to the vacancy-oxygen pair which is partly saturated with hydrogen

  11. Chemical flowsheet conditions for preparing urania spheres by internal gelation

    International Nuclear Information System (INIS)

    Haas, P.A.; Begovich, J.M.; Ryon, A.D.; Vavruska, J.S.

    1979-01-01

    Small, ceramic urania spheres can be prepared for use as nuclear fuel by internal chemical gelation of uranyl nitrate solution droplets. Decomposition of hexamethylenetetramine (HMTA) dissolved in the uranyl nitrate solution releases ammonia to precipitate hydrated UO 3 . Previously established flowsheet conditions have been improved and modified at ORNL and have been applied to prepare dense UO 2 spheres with average diameters of 1200, 300, and 30 μm. Acid-deficient uranyl nitrate (ADUN) solutions up to 3.4 M in uranium with NO 3 - /U mole ratios of 1.5 to 1.7 are prepared by dissolution of U 3 O 8 or UO 3 . Continuous mixing of metered, cooled ADUN containing urea and HMTA solutions provides a smooth, regulated flow of the temperature-sensitive feed solution. The gelation times for solution drops in organic liquids at 45 to 95 0 C depend on both the chemical reaction rates and the rates of heat transfer. The gel properties vary with temperature and other gelation variables. Gelation conditions were determined which allow easy washing, drying, firing, and sintering to produce dense UO 2 spheres of all three sizes. The 1200- and 300-μm UO 2 spheres were pepared by gelation in trichloroethylene at 50 to 65 0 C; 2-ethyl-l-hexanol was used as the gelation medium to prepare 30-μm UO 2 spheres. Washing and drying requirements were determined. The gel dried to 225 0 C contains about 95% UO 3 ; the remaining components are H 2 O, NH 3 - , which are volatilized during firing to UO 2

  12. A roadmap to high quality chemically prepared graphene

    Energy Technology Data Exchange (ETDEWEB)

    Gengler, Regis Y N; Spyrou, Konstantinos; Rudolf, Petra, E-mail: r.gengler@rug.n, E-mail: p.rudolf@rug.n [Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen (Netherlands)

    2010-09-22

    Graphene was discovered half a decade ago and proved the existence of a two-dimensional system which becomes stable as a result of 3D corrugation. It appeared very quickly that this exceptional material had truly outstanding electronic, mechanical, thermal and optical properties. Consequently a broad range of applications appeared, as the graphene science speedily moved forward. Since then, a lot of effort has been devoted not only to the study of graphene but also to its fabrication. Here we review the chemical approaches to graphene production, their advantages as well as their downsides. Our aim is to draw a roadmap of today's most reliable path to high quality graphene via chemical preparation.

  13. A roadmap to high quality chemically prepared graphene

    International Nuclear Information System (INIS)

    Gengler, Regis Y N; Spyrou, Konstantinos; Rudolf, Petra

    2010-01-01

    Graphene was discovered half a decade ago and proved the existence of a two-dimensional system which becomes stable as a result of 3D corrugation. It appeared very quickly that this exceptional material had truly outstanding electronic, mechanical, thermal and optical properties. Consequently a broad range of applications appeared, as the graphene science speedily moved forward. Since then, a lot of effort has been devoted not only to the study of graphene but also to its fabrication. Here we review the chemical approaches to graphene production, their advantages as well as their downsides. Our aim is to draw a roadmap of today's most reliable path to high quality graphene via chemical preparation.

  14. L1{sub 0}-FePt films fabricated by wet-chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Xiaoliang; Xiao, Wen; Bao, Nina; Li, Weimin; Chichvarina, Olga, E-mail: A0077107@nus.edu.sg; Ding, Jun, E-mail: msedingj@nus.edu.sg

    2015-08-31

    In this work, we have developed a method to fabricate FePt films by a combination of chemical deposition and post-annealing. Pt-doped Fe films were deposited on Pt(100 nm)/Ti(50 nm)/SiO{sub 2}/Si substrate using thermal deposition and the as-deposited films were subsequently annealed from 300 °C to 800 °C under 5% H{sub 2}/95% N{sub 2}. FePt films were achieved through diffusion and rearrangement of Fe and Pt atoms in post-annealing process. From X-ray diffraction results, the face-centered cubic (fcc) FePt phase appeared at 300 °C and the transformation from fcc to L1{sub 0} phase started at 400 °C. The L1{sub 0}-FePt film possessed an out-of-plane anisotropy and a coercivity of 729 kA/m after annealing at 600 °C. A further increase in annealing temperature led to lower value of coercivity, probably because of grain growth. In addition, the thickness of Pt-doped Fe films could be controlled from 150 nm to 700 nm by adjusting the amount of surfactant used. Our superconducting quantum interference device analysis showed that Pt dopant could significantly improve the chemical stability of Fe films in air. - Highlights: • We fabricated FePt film by a combination of chemical deposition and post-annealing. • L1{sub 0} FePt film was formed by Fe/Pt diffusion in annealing of Pt-doped Fe film. • L1{sub 0}-phase FePt with high coercivity and small out-of-plane anisotropy • Relatively small amount of Pt dopant can enhance chemical stability greatly. • We studied structure and magnetic property of as-deposited and annealed FePt film.

  15. Wet Chemical Oxidation of Organic Waste Using Nitric-Phosphoric Acid Technology

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, R.A.

    1998-10-06

    Experimental progress has been made in a wide range of areas which support the continued development of the nitric-phosphoric acid oxidation process for combustible, solid organic wastes. An improved understanding of the overall process operation has been obtained, acid recovery and recycle systems have been studied, safety issues have been addressed, two potential final waste forms have been tested, preliminary mass flow diagrams have been prepared, and process flowsheets have been developed. The flowsheet developed is essentially a closed-loop system which addresses all of the internally generated waste streams. The combined activities aim to provide the basis for building and testing a 250-400 liter pilot-scale unit. Variations of the process now must be evaluated in order to address the needs of the primary customer, SRS Solid Waste Management. The customer is interested in treating job control waste contaminated with Pu-238 for shipment to WIPP. As a result, variations for feed preparation, acid recycle, and final form manufacturing must be considered to provide for simpler processing to accommodate operations in high radiation and contamination environments. The purpose of this program is to demonstrate a nitric-phosphoric acid destruction technology which can treat a heterogeneous waste by oxidizing the solid and liquid organic compounds while decontaminating noncombustible items.

  16. ABB wet flue gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Niijhawan, P.

    1994-12-31

    The wet limestone process for flue gas desulfurization (FGD) is outlined. The following topics are discussed: wet flue gas desulfurization, wet FGD characteristics, wet scrubbers, ABB wet FGD experience, wet FGD forced oxidation, advanced limestone FGD systems, key design elements, open spray tower design, spray tower vs. packed tower, important performance parameters, SO{sub 2} removal efficiency, influence by L/G, limestone utilization, wet FGD commercial database, particulate removal efficiencies, materials of construction, nozzle layout, spray nozzles, recycle pumps, mist elimination, horizontal flow demister, mist eliminator washing, reagent preparation system, spray tower FGDS power consumption, flue gas reheat options, byproduct conditioning system, and wet limestone system.

  17. Sequential Ar-O2 sputtering of Y2O3, BaF2, and CuO targets for preparation of Y-Ba-Cu-O superconducting films without wet-O2 annealing

    International Nuclear Information System (INIS)

    Bhushan, M.; Strauss, A.J.; Finn, M.C.

    1989-01-01

    Superconducting Y-Ba-Cu-O (YBCO) films have been prepared by ex situ O 2 annealing of multilayer films deposited on yttria-stabilized zirconia substrates by sequential rf diode sputtering of Y 2 O 3 , BaF 2 , and CuO targets, all of which are chemically stable. If sputtering is performed in an Ar ambient, the as-deposited films contain sufficient F to require its removal by annealing in wet O 2 at about 800 degree C or above before the superconducting YBCO phase can be formed by annealing in dry O 2 . However, sputtering in an Ar-O 2 ambient greatly reduces the F content, making it possible to obtain the superconducting phase by annealing in dry O 2 only. If the ambient contains about 20% O 2 , films with T c (R=0)>85 K can be prepared without wet-O 2 annealing. The Ar-O 2 process therefore has the potential for in situ preparation of superconducting YBCO films

  18. Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

    Full Text Available In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer for the detection of nitrous acid (HONO in the atmosphere (DL 0.2 pptV was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

  19. Controlled low-temperature fabrication of ZnO nanopillars with a wet-chemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Postels, B [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Kreye, M [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Fuhrmann, D [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Blaesing, J [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Hangleiter, A [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Krost, A [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Waag, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

    2007-05-16

    Aqueous chemical growth (ACG) is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars on various substrate materials. ACG is a low-temperature growth approach that is only weakly influenced by the substrate and even allows growth on flexible polymer substrates or on conducting materials. The advanced fabrication of wafer-scale and highly vertically aligned arrays of ZnO nanopillars on various substrate materials is demonstrated. Moreover, it is possible to control the morphology in diameter and length by changing the growth conditions. Photoluminescence characterization clearly shows a comparatively strong band-edge luminescence, even at room temperature, that is accompanied by a rather weak visible luminescence in the yellow/orange spectral range.

  20. Radiation chemical route for preparation of metal nanoparticles

    International Nuclear Information System (INIS)

    Kapoor, S.; Mukherjee, T.

    2006-01-01

    Nanoparticles show properties that are neither seen in the bulk or at atomic level. The unusual properties are governed by quantum size effect. Due to this various methodologies have been endeavored to control the size of the particles. In the present work we show the use of two complimentary techniques (radiation and photo) to synthesize and control the size of the metal particles. In-situ synthesis of fine silver, thallium and cadmium particles has been carried out by gamma-irradiation and electron pulse irradiation at room temperature in the pre-organized gel of polyacrylamide or cyclodextrin cavity. The role of generation of nuclei in high concentrations in stabilization of metal nanoparticles in hydrophobic cavity is shown. Similarly the importance of entrapment of metal ions in the polymer matrix during its formation is highlighted. The work is further extended to exploit the microemulsion droplets for stabilization of Cd nanoparticles. Utility of pulse radiolysis in probing the mechanism of the formation of metal nanoparticles is also shown. Ultrafast laser pulses were employed to control the morphology of the pre-prepared Pt nanoparticles. The changes in reduction of shape and size are considered to occur through melting and vaporization of the nanoparticles. Pt nanoparticles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at ≥150 degree C giving CO 2 . Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave ∼7% CO conversion per hr. However, radiolytically prepared Pt nanoaprticles stabilized by gelatin gave ∼10% conversion per hr. The data indicates that catalytic oxidation of CO takes place

  1. [Our medicinal preparations in the mid-19th century. Part I--Introduction and chemical preparations].

    Science.gov (United States)

    Drábek, Pavel

    2012-08-01

    The paper deals with the development of the first editions of the Austrian Pharmacopoeia, Pharmacopoea Austriaca, since its origin in the year 1812. It demonstrates its gradual retardation in the period when nearly all medicinal substances had to be prepared only in pharmacies. The conception was changed as late as 1855 in the Fifth Edition, when it was allowed to buy many medicinal substances from producers or wholesalers. At the same time, requirements for organoleptic properties and chemical purity began to be introduced. The present communication also deals with the chemical drugs used in the mid-19th century and is based on a comparison of the pharmacopoeias of 1836 and 1855. It presents some typical examples, such as alkaloids and metal compounds.

  2. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Jascha [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Potsdam Institute for Climate Impact Research (PIK), 14473 Potsdam (Germany); Lehmann, Sebastian, E-mail: sebastian.lehmann@ftf.lth.se [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Solid State Physics, Lund University, Box 118, S-22100 Lund (Sweden); Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch. [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Bär, Marcus, E-mail: marcus.baer@helmholtz-berlin.de [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus (Germany); Sadewasser, Sascha, E-mail: sascha.sadewasser@inl.int [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga (Portugal)

    2014-12-21

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for “realistic” surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In{sub 1-x}Ga{sub x})Se{sub 2} thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH{sub 3}-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is – apart from a slight change in surface composition – identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  3. Microbial safety and overall quality of cantaloupe fresh-cut pieces prepared from whole cantaloupe after wet steam treatment

    Science.gov (United States)

    Fresh-cut cantaloupes have been associated with outbreaks of Salmonelosis disease and the minimally processed fresh-cut fruits have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. In this study, we evaluated the effect of minimal wet steam t...

  4. Microbial safety and overall quality of cantaloupe fresh-cut pieces prepared from whole fruit after wet steam treatment

    Science.gov (United States)

    Fresh-cut cantaloupes have been associated with outbreaks of Salmonellosis. Minimally processed fresh-cut fruits have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. The objectives of this study were to use a wet steam process to 1) reduce ind...

  5. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H 2 SO 4 and CaCl 2 . Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H 2 SO 4 and CaCl 2 ; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Radiation-chemical preparation of poly(vinyl alcohol) hydrogels

    International Nuclear Information System (INIS)

    Duflot, Anastasia V.; Kitaeva, Natalia K.; Duflot, Vladimir R.

    2015-01-01

    This work reports the usage of method of radiation-chemical synthesis to prepare cross-linked hydrogels from poly(vinyl alcohol) modified with glycidyl methacrylate. Synthesis kinetics of modified poly(vinyl alcohol) and properties of hydrogels were studied. The gel fraction, swelling, mechanical properties, and water content of the hydrogels were measured. It was found that gel fraction increases with increasing radiation dose, concentration of modified poly(vinyl alcohol), and reaches 60%. It was established by differential scanning calorimetry that a fraction of the “bound” water in hydrogels is 50–70% and independent of gel fraction content. In addition to “bound” and “free” states, water in hydrogels is also present in the intermediate state. - Highlights: • The synthesis and the properties of poly(vinyl alcohol) hydrogels were studied. • PVA was modified by glycidyl methacrylate before gamma cross-linking. • The modification results in decreasing of PVA cross-linking dose by 3 orders lower. • The gel fraction and water content of the hydrogels were measured. • A fraction of the “bound” water in hydrogels is independent of gel fraction content

  7. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda

    2002-01-01

    Wheat straw (Triticum aestivum) and beech (Fagus sylvatica), were used to evaluate the effects of two pre-treatment processes (alkaline wet oxidation and enzyme treatment with laccase) on lignocellulosic materials for applications in particleboards and fiberboards. Wheat straw and beech fibers...... treatment gave a more reactive surface than alkaline wet oxidation for wheat straw, whereas the opposite was observed for beech. Fourier transform infrared (FT-IR) spectroscopy showed an almost complete loss of the ester carbonyl stretching signal and the corresponding C-C-O stretching in wet...

  8. Audit Report. Johnston Atoll Chemical Agent Disposal System Preparation for Year 2000

    National Research Council Canada - National Science Library

    1998-01-01

    .... The overall audit objective was to determine whether the Johnston Atoll Chemical Agent Disposal System was adequately preparing its information technology systems to resolve date-processing issues...

  9. Evaluation of Wet Chemical ICP-AES Elemental Analysis Methods using Simulated Hanford Waste Samples-Phase I Interim Report

    International Nuclear Information System (INIS)

    Coleman, Charles J.; Edwards, Thomas B.

    2005-01-01

    The wet chemistry digestion method development for providing process control elemental analyses of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Melter Feed Preparation Vessel (MFPV) samples is divided into two phases: Phase I consists of: (1) optimizing digestion methods as a precursor to elemental analyses by ICP-AES techniques; (2) selecting methods with the desired analytical reliability and speed to support the nine-hour or less turnaround time requirement of the WTP; and (3) providing baseline comparison to the laser ablation (LA) sample introduction technique for ICP-AES elemental analyses that is being developed at the Savannah River National Laboratory (SRNL). Phase II consists of: (1) Time-and-Motion study of the selected methods from Phase I with actual Hanford waste or waste simulants in shielded cell facilities to ensure that the methods can be performed remotely and maintain the desired characteristics; and (2) digestion of glass samples prepared from actual Hanford Waste tank sludge for providing comparative results to the LA Phase II study. Based on the Phase I testing discussed in this report, a tandem digestion approach consisting of sodium peroxide fusion digestions carried out in nickel crucibles and warm mixed-acid digestions carried out in plastic bottles has been selected for Time-and-Motion study in Phase II. SRNL experience with performing this analytical approach in laboratory hoods indicates that well-trained cell operator teams will be able to perform the tandem digestions in five hours or less. The selected approach will produce two sets of solutions for analysis by ICP-AES techniques. Four hours would then be allocated for performing the ICP-AES analyses and reporting results to meet the nine-hour or less turnaround time requirement. The tandem digestion approach will need to be performed in two separate shielded analytical cells by two separate cell operator teams in order to achieve the nine-hour or less turnaround

  10. Chemical preparation of graphene-based nanomaterials and their applications in chemical and biological sensors.

    Science.gov (United States)

    Jiang, Hongji

    2011-09-05

    Graphene is a flat monolayer of carbon atoms packed tightly into a 2D honeycomb lattice that shows many intriguing properties meeting the key requirements for the implementation of highly excellent sensors, and all kinds of proof-of-concept sensors have been devised. To realize the potential sensor applications, the key is to synthesize graphene in a controlled way to achieve enhanced solution-processing capabilities, and at the same time to maintain or even improve the intrinsic properties of graphene. Several production techniques for graphene-based nanomaterials have been developed, ranging from the mechanical cleavage and chemical exfoliation of high-quality graphene to direct growth onto different substrates and the chemical routes using graphite oxide as a precusor to the newly developed bottom-up approach at the molecular level. The current review critically explores the recent progress on the chemical preparation of graphene-based nanomaterials and their applications in sensors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Preparation of zinc ferrite nano powders by high energy wet-milling method and investigation of Crystallites size variation during this process

    International Nuclear Information System (INIS)

    Masoudi, H.; Aftabi, A.; Mozafari, M.; Amighian, J.

    2007-01-01

    In this research work ZnFe 2 O 4 nano powders were prepared by high-energy wet-milling process, using metallic Fe and Zn powders. The process was investigated by XRD technique. 10% of the zinc ferrite was formed after 10 h milling. The as-milled sample was annealed at 500, 550 and 600 d egree C . Ultimately a single sample was obtained at 600 d egree C . Using sherrer's formula, the mean crystallite size of the as-milled and annealed powders were calculated. These were in the range of 17.9 to 20.4 nm.

  12. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    Energy Technology Data Exchange (ETDEWEB)

    Bjerre, A B; Skammelsen Schmidt, A

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates `losses` of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation.

  13. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    International Nuclear Information System (INIS)

    Bjerre, A.B.; Skammelsen Schmidt, A.

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates 'losses' of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation

  14. Electrical properties of chemically prepared nonstoichiometric CuIn ...

    Indian Academy of Sciences (India)

    TECS

    2; thin films; chemical bath deposition technique; d.c. conductivity; thermoelectric .... In a semiconductor, temperature gradient yields the thermo- ... to form the metal complex (Chavan and Sharma 2005) .... Thesis, University of Rajasthan, Jaipur.

  15. Preparation of β-Li{sub 2}TiO{sub 3} pebbles by a modified indirect wet chemistry method

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Cheng-Long, E-mail: johnyucl@aliyun.com [School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); Research Laboratory of Hydrothermal Chemistry, Faculty of Science, The Kochi University, Kochi 780-8520 (Japan); Wang, Fei; Zhang, Ai-Lin; Gao, Dan-Peng; Cao, Shu-Yao [School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); Guo, Ying-Yan [College of Resources and Environment, Shaanxi University of Science & Technology, Xi’an 710021 (China); Hui, Huai-Bin [School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); Technology Research Institute, Technical Center at Dongfeng Commercial Vehicle Company Limited, Wuhan 430056 (China); Hao, Xin [School of Management, Shaanxi University of Science & Technology, Xi’an 710021 (China); Wang, Dao-Yi [School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); Yanagisawa, Kazumichi [Research Laboratory of Hydrothermal Chemistry, Faculty of Science, The Kochi University, Kochi 780-8520 (Japan)

    2015-12-15

    Graphical abstract: β-Li{sub 2}TiO{sub 3} pebbles with about 1.56 mm in diameter, a better sphericity of 1.02 and relative sintered density of 95.8%T.D. are successfully fabricated when sintered at 1100 °C for 6 h in ambient conditions. - Highlights: • β-Li{sub 2}TiO{sub 3} powders via hydrothermal method are used as raw materials. • A mixture of the acetone and carbon tetrachloride bath is used. • The wet gel pebbles can be fabricated at room temperature. - Abstract: β-Li{sub 2}TiO{sub 3} pebbles were fabricated by a modified indirect wet chemistry method. The first feature lies in that β-Li{sub 2}TiO{sub 3} powders via hydrothermal method were used as raw materials. The second one lies in that a mixture of the acetone and carbon tetrachloride was used for formation and aging of the pebbles at room temperature. The phase identification of the β-Li{sub 2}TiO{sub 3} sintered pebbles was conducted by the X-ray Diffraction analysis. The morphology of the sintered β-Li{sub 2}TiO{sub 3} pebbles was observed by Field Emission Scanning Electron Microscope. The experimental results show that the β-Li{sub 2}TiO{sub 3} pebbles with about 1.56 mm in diameter, a better sphericity of 1.02 and relative sintered density of 95.8%T.D. are successfully fabricated when sintered at 1100 °C for 6 h in ambient conditions. The grains in the pebbles are polyhedral brick-shaped, and homogeneous in size distribution. The morphology evolution and relative density of the β-Li{sub 2}TiO{sub 3} pebbles are governed by the sintering temperature, between 1050 °C and 1150 °C. More homogeneous in grain size, less porosity, and higher densification of the β-Li{sub 2}TiO{sub 3} pebbles can be obtained at 1100 °C.

  16. A novel nano-hydroxyapatite — PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    G, Radha [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); S, Balakumar, E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025 (India)

    2017-06-01

    In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The higher degree of porous architecture was achieved from Ace scaffolds compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of the I-W scaffold exhibited superior hardness and compressive strength than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

  17. A novel nano-hydroxyapatite – PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Radha, G. [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Balakumar, S., E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy campus, Chennai 600025 (India)

    2017-04-01

    In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The porosity of ~ 57.89% was achieved from Ace scaffold that was higher degree compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of I-W scaffold exhibited superior hardness of ~ 65.6 HR ‘D’ than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

  18. Artificially regenerating longleaf pine on wet sites: preliminary analysis of effects of site preparation treatments on early survival and growth

    Science.gov (United States)

    Benjamin O. Knapp; G. Geoff Wang; Joan L. Walker

    2010-01-01

    Our study, conducted over two years on poorly drained, sandy sites in Onslow County, NC, compared the effects of eight common site preparation treatments on early survival and growth of planted longleaf pine seedlings. Through two growing seasons, we found survival to be similar across all treatments (p = 0.8806), but root collar diameter was greatest with combinations...

  19. Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

    Directory of Open Access Journals (Sweden)

    Linglong Yao

    2018-02-01

    Full Text Available In this work, polyvinylpyrrolidone (PVP coated Mg95Ni5 nano-composites were prepared by hydriding combustion synthesis (HCS plus wet mechanical milling (WM with tetrahydrofuran (THF and donated as WM-x wt% PVP (x = 1, 3, 5 and 7 respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH2 in the milled Mg95Ni5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH2 in the milled Mg95Ni5 decreased from 293.0 °C without THF to 250.4 °C with THF. The apparent activation energy for decomposition of MgH2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg95Ni5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties. Keywords: Mg-Ni-PVP, Composite, Mg-based alloy, Wet mechanical milling, Dehydriding temperature

  20. Wet chemical synthesis of quantum confined nanostructured tin oxide thin films by successive ionic layer adsorption and reaction technique

    Energy Technology Data Exchange (ETDEWEB)

    Murali, K.V., E-mail: kvmuralikv@gmail.com [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Nehru Arts and Science College, Kanhangad, Kerala 671314 (India); Ragina, A.J. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Nehru Arts and Science College, Kanhangad, Kerala 671314 (India); Preetha, K.C. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Sree Narayana College, Kannur, Kerala 670007 (India); Deepa, K.; Remadevi, T.L. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Pazhassi Raja N.S.S. College, Mattannur, Kerala 670702 (India)

    2013-09-01

    Graphical abstract: - Highlights: • Quantum confined SnO{sub 2} thin films were synthesized at 80 °C by SILAR technique. • Film formation mechanism is discussed. • Films with snow like crystallite morphology offer high specific surface area. • The blue-shifted value of band gap confirmed the quantum confinement effect. • Present synthesis has advantages – low cost, low temperature and green friendly. - Abstract: Quantum confined nanostructured SnO{sub 2} thin films were synthesized at 353 K using ammonium chloride (NH{sub 4}Cl) and other chemicals by successive ionic layer adsorption and reaction technique. Film formation mechanism is discussed. Structural, morphological, optical and electrical properties were investigated and compared with the as-grown and annealed films fabricated without NH{sub 4}Cl solution. SnO{sub 2} films were polycrystalline with crystallites of tetragonal structure with grain sizes lie in the 5–8 nm range. Films with snow like crystallite morphology offer high specific surface area. The blue-shifted value of band gap of as-grown films confirmed the quantum confinement effect of grains. Refractive index of the films lies in the 2.1–2.3 range. Films prepared with NH{sub 4}Cl exhibit relatively lower resistivity of the order of 10{sup 0}–10{sup −1} Ω cm. The present synthesis has advantages such as low cost, low temperature and green friendly, which yields small particle size, large surface–volume ratio, and high crystallinity SnO{sub 2} films.

  1. Morphology-controlled SWCNT/polymeric microsphere arrays by a wet chemical self-assembly technique and their application for sensors

    International Nuclear Information System (INIS)

    Huang Xingjiu; Li Yue; Im, Hyung-Soon; Yarimaga, Oktay; Kim, Ju-Hyun; Jang, Doon-Yoon; Cho, Sung-Oh; Cai Weiping; Choi, Yang-Kyu

    2006-01-01

    Large-scale morphology-controlled SWCNT/polymeric microsphere arrays can be obtained by a wet chemical self-assembly technique. The loading of SWCNTs, the length of SWCNTs, and the size and nature of polymeric microspheres can easily be controlled. Similar results can also be reached using this method for MWCNTs. In both types of CNTs, they form an interesting interactive 'net' structure on spheres and sphere joints. The SWCNT/PS-modified Au electrode was used for detection of uric acid by cyclic voltammetry and single-potential time-based techniques. The preliminary results show that the modified electrode presents good sensitivity and stability to uric acid

  2. Structure and magnetic properties of Zn1-xCoxO single-crystalline nanorods synthesized by a wet chemical method

    International Nuclear Information System (INIS)

    Wang Hao; Wang, H B; Yang, F J; Chen, Y; Zhang, C; Yang, C P; Li, Q; Wong, S P

    2006-01-01

    A novel approach for the synthesis of cobalt-doped ZnO single-crystalline nanorods based on a wet chemical reaction has been developed. The as-doped ZnO nanorods have a length between 0.3 and 0.6 μm and a diameter between 30 and 60 nm. Structure and composition analyses indicate that the cobalt is incorporated into the ZnO lattice, forming a solid solution without any precipitation. Magnetic property measurements reveal that there is room-temperature ferromagnetism in the Zn 1-x Co x O nanorods with T c higher than 300 K

  3. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner...... conjugates and their use in vaccination, production of antibodies, high throughput screening, diagnostic assays and libraries....

  4. Sample Preparation and Identification of Biological, Chemical and Mid-Spectrum Agents

    National Research Council Canada - National Science Library

    Hancock, J. R; Dragon, D. C

    2005-01-01

    A general survey of sample preparation and identification techniques for biological, chemical and mid-spectrum agents was conducted as part of Canada's contribution to a joint NATO Allied Engineering Publication (AEP) handbook...

  5. Oriented Y-typehexagonal ferrite thin films prepared by chemical

    Czech Academy of Sciences Publication Activity Database

    Buršík, Josef; Kužel, R.; Knížek, Karel; Drbohlav, Ivo

    2013-01-01

    Roč. 203, JULY (2013), s. 100-105 ISSN 0022-4596 R&D Projects: GA ČR GA13-03708S Institutional support: RVO:61388980 ; RVO:68378271 Keywords : Y-type hexagonal ferrites * chemical solution deposition * thin films * epitaxial growth Subject RIV: CA - Inorganic Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 2.200, year: 2013

  6. Preparation of Nanofibrous Silver/Poly(vinylidene fluoride) Composite Membrane with Enhanced Infrared Extinction and Controllable Wetting Property.

    Science.gov (United States)

    Ren, Da-Ming; Huang, Hua-Kun; Yu, Yun; Li, Zeng-Tian; Jiang, Li-Wang; Chen, Shui-Mei; Lam, Kwok-Ho; Lin, Bo; Shi, Bo; He, Fu-An; Wu, Hui-Jun

    2018-05-01

    Nanofibrous silver (Ag)/poly(vinylidene fluoride) (PVDF) composite membranes were obtained from a two-step preparation method. In the first step, the electrospun silver nitrate (AgNO3)/PVDF membranes were prepared and the influence of the AgNO3 content on the electrospinning process was studied. According to scanning electron microscopy (SEM) results, when the electrospinning solution contained AgNO3 in the range between 3 to 7 wt.%, the nanofiber morphologies can be obtained. In the second step, the electrospun AgNO3/PVDF membranes were reduced by sodium borohydride to form the nanofibrous Ag/PVDF composite membranes. The resultant composite membranes were characterized by SEM, X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), differential scanning calorimetry, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared. The XRD, XPS, and EDS characterizations proved the existence of Ag in the nanofibrous Ag/PVDF composite membranes. The crystallinity degree of PVDF for composite membranes declined with the increase in Ag content. More importantly, the nanofibrous Ag/PVDF composite membranes had obviously higher Rosseland extinction coefficients and lower thermal radiative conductivities in comparison with electrospun PVDF membrane, which demonstrates that such composite membranes with high porosity, low density, and good water vapor permeability are promising thermal insulating materials to block the heat transfer resulting from thermal radiation. In addition, three different methods for surface modification have been used to successfully improve the hydrophobicity of nanofibrous Ag/PVDF composite membranes.

  7. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Brusasco, R.M.

    1989-01-01

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs

  8. Sample preparation for combined chemical analysis and bioassay application in water quality assessment

    NARCIS (Netherlands)

    Kolkman, A.; Schriks, M.; Brand, W; Bäuerlein, P.S.; van der Kooi, M.M.E.; van Doorn, R.H.; Emke, E.; Reus, A.; van der Linden, S.; de Voogt, P.; Heringa, M.B.

    2013-01-01

    The combination of in vitro bioassays and chemical screening can provide a powerful toolbox to determine biologically relevant compounds in water extracts. In this study, a sample preparation method is evaluated for the suitability for both chemical analysis and in vitro bioassays. A set of 39

  9. 1.3. Chemical and mineral additives of concretes and water used for concrete mix preparation

    International Nuclear Information System (INIS)

    Saidov, D.Kh.

    2011-01-01

    It is known that chemical and mineral additives increase physicochemical properties of concretes, thus, chemical and mineral additives, including super plasticizer and organo mineral additives are examined in this work. It was noted that along with salt water fresh water can also be used for concrete mix preparation.

  10. Preparation and characterization of a chemically sulfated cashew gum polysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Moura Neto, Erico de; Maciel, Jeanny da S.; Cunha, Pablyana L. R.; Paula, Regina Celia M. de; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza (Brazil)

    2011-09-15

    Cashew gum (CG) was sulfated in pyridine:formamide using chlorosulfonic acid as the reagent. Confirmation of sulfation was obtained by Fourier transform infrared (FTIR) spectroscopy through the presence of an asymmetrical S=O stretching vibration at 1259 cm{sup -1}. The degrees of substitution were 0.02, 0.24 and 0.88 determined from the sulfur percentage. 1D and 2D nuclear magnetic resonance (NMR) data showed that the sulfation occurred at primary carbons. An increase of at least 4% of the solution viscosity was observed due to sulfation. The thermal gravimetric curves (TGA) indicate that the derivatives are stable up to ca. 200 deg C. The sulfated CG is compared to carboxymethylated CG in order to verify the possibility of the use of the former in the preparation of polyelectrolyte complexes; the latter is already being used for this application. (author)

  11. [Wet work].

    Science.gov (United States)

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  12. Preparation of hafnium carbide by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hertz, Dominique.

    1974-01-01

    Hard, adhesive coatings of single-phase hafnium carbide were obtained by chemical vapor reaction in an atmosphere containing hafnium tetrachloride, methane and a large excess of hydrogen. By varying the gas phase composition and temperature the zones of formation of the different solid phases were studied and the growth of elementary hafnium and carbon deposits evaluated separately. The results show that the mechanism of hafnium carbide deposition does not hardly involve phenomene of homogeneous-phase methane decomposition or tetrachloride reduction by hydrogen unless the atmosphere is very rich or very poor in methane with respect to tetrachloride. However, hydrogen acting inversely on these two reactions, affects the stoichiometry of the substance deposited. The methane decomposition reaction is fairly slow, the reaction leading to hafnium carbide deposition is faster and that of tetrachloride reduction by hydrogen is quite fast [fr

  13. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  14. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    Science.gov (United States)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste

  15. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Basudev, E-mail: swain@iae.re.kr [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Mishra, Chinmayee [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Hong, Hyun Seon [Sungshin University, Dept. of Interdisciplinary ECO Science, Seoul, 142-732 (Korea, Republic of); Cho, Sung-Soo [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of)

    2016-05-15

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m{sup 3} of copper and 1.35 kg/m{sup 3} of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching

  16. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    International Nuclear Information System (INIS)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-01-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m 3 of copper and 1.35 kg/m 3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching wastewater

  17. [Preparation of the database and the Internet (WWW) homepage for regulations on chemicals in Japan].

    Science.gov (United States)

    Yamamoto, M; Morita, M; Kaminuma, T

    1999-01-01

    We prepared a database on chemical regulations in Japan. The regulations consist of "The Law concerning the Examination and Regulation of Manufacture, etc., of Chemical Substances", "Poisonous and Deleterious Substances", Control Law", "Waterworks Law", "Law for the Control of Household Products containing Harmful Substances", and Pesticide Residues in Food Sanitation Law". We also set up a World Wide Web (WWW) homepage containing an explanation of the law as well as chemical names, CAS registry numbers, and standards. The WWW pages contain lists of chemicals and the retrieval page for the database.

  18. Chemical-wet Synthesis and Electrochemistry of LiNi1/3Co1/3Mn1/3O2 Cathode Materials for Li-ion Batteries

    International Nuclear Information System (INIS)

    Hsieh, Chien-Te; Mo, Chung-Yu; Chen, Yu-Fu; Chung, Yi-Jou

    2013-01-01

    LiNi 1/3 Co 1/3 Mn 1/3 O 2 (LNCM) with a well-ordered layered structure, confirmed by X-ray diffraction, was synthesized by the chemical-wet synthesis incorporated with (i) a pulse microwave-assisted heating of LNCM precursors and (ii) a carbon coating technique. The microwave irradiation periods (i.e., 5–20 min) and amount of carbon additive (i.e., glucose content: 0.1–0.75%) served as key factors in modifying as-prepared LNCM powders. The electrochemical performance of as-prepared LNCM cathodes was well characterized by cyclic voltammetry and charge–discharge cycling at 0.1–5C. Both appropriate microwave heating and carbon coating significantly improve discharge capacity, rate capability, and cycling stability of LNCM cathodes. This improved performance can be attributed to the facts that an appropriate microwave heating of LNCM precursors induces low cation mixing of the layered lattices and the carbon coating enables the creation of outer circuit of charge-transfer pathway, preventing cathode corrosion from direct contact to the electrolyte. The C-coated LNCM cathode shows the increased capacity retention from 70.2 to 93.3% after 50 cycles at 1C. On the basis of the experimental results, both the microwave heating and the carbon coating provide a feasible potential way to improve the electrochemical performance of LNCM cathode, benefiting the development of Li-ion batteries

  19. SAFETY STUDIES TO MEASURE EXOTHERMIC REACTIONS OF SPENT PLUTONIUM DECONTAMINATION CHEMICALS USING WET AND DRY DECONTAMINATION METHODS

    International Nuclear Information System (INIS)

    HOPKINS, A.M.; JACKSON, G.W.; MINETTE, M.; EWALT, J.; COOPER, T.; SCOTT, P.; JONES, S.; SCHEELEY, R.

    2005-01-01

    The Plutonium Finishing Plant (PFP) at the Hanford site in Eastern Washington is currently being decommissioned by Fluor Hanford. Chemicals being considered for dccontamination of gloveboxes in PFP include cerium (IV) nitrate in a nitric acid solution, and proprietary commercial solutions that include acids and sequestering agents. Aggressive chemicals are commonly used to remove transuranic contaminants from process equipment to allow disposal of the equipment as low level waste. Fluor's decontamination procedure involves application of chemical solutions as a spray on the contaminated surfaces, followed by a wipe-down with rags. Alternatively, a process of applying oxidizing Ce IV ions contained in a gel matrix and vacuuming a dry gel material is being evaluated. These processes effectively transfer the transuranic materials to rags or a gel matrix which is then packaged as TRU waste and disposed

  20. Exploring the Potential of Different-Sized Supported Subnanometer Pt Clusters as Catalysts for Wet Chemical Applications

    KAUST Repository

    Rondelli, Manuel; Zwaschka, Gregor; Krause, Maximilian; Rö tzer, Marian D.; Hedhili, Mohamed N.; Hogerl, Manuel Peter; D’ Elia, Valerio; Schweinberger, Florian F.; Basset, Jean-Marie; Heiz, Ueli

    2017-01-01

    as catalysts for organic chemistry transformations in solution has not been explored. To this end, single Pt atoms and Pt clusters with two narrow size distributions were prepared in the UHV and applied for the hydrogenation of p-chloronitrobenzene to p

  1. Wet chemical synthesis of nickel supported on alumina catalysts; Sintese de catalisadores de niquel suportado em alumina por via umida

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de, E-mail: normanda@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2016-07-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al{sub 2}O{sub 3}), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl{sub 2}O{sub 4}. The Al{sub 2}O{sub 3} e Ni/Al{sub 2}O{sub 3} catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al{sub 2}O{sub 3} and Ni/Al{sub 2}O{sub 3} catalysts were 8.69 m{sup 2}/g and 5.56 m{sup 2}/g, respectively. (author)

  2. Testing Dust Control Preparation with Respect to Mine Employee Exposure to Inhalling Chemical Agents

    Directory of Open Access Journals (Sweden)

    Eugeniusz Orszulik

    2013-01-01

    Full Text Available This paper presents the results of tests used in dust hazard prevention for air-water spraying devices in collieries. The purpose of the tests was to evaluate mine employees’ exposure to inhalling chemical agents when the ZWILKOP ZW-10 preparation is used. The paper presents the results of the measurements of concentration, in a mine atmosphere, of the following chemical agents: hazardous substances 2-(2-butoxyethoxyethanol and 2-ethylhexan-1-ol, constituting ingredients of the preparation at mine employees’ workstations. The tests were performed during work related to the mining of coal in inclined drift C31, seam 415/1-2 on the premises of “Borynia-Zofiówka-Jastrzębie” Hard Coal Mine, Jastrzębie-Zdrój, Poland, using the TELESTO mist systems. Using aqueous solutions for the preparation at concentrations of 15 and 20‰ causes no exceedance of the allowable mine air concentrations for the chemical agents tested.

  3. Study of the influence of thermal treatment on the magnetic properties of lithium ferrite prepared by wet ball-milling using nitrates as raw material

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, S. Soreto, E-mail: silvia.soreto@ua.pt; Graça, M.P.F., E-mail: mpfg@ua.pt; Costa, L.C., E-mail: kady@ua.pt; Valente, M.A., E-mail: mav@ua.pt

    2014-08-01

    Graphical abstract: - Highlights: • The saturation magnetization increases with heat-treatment temperature until 1200 °C. • 1200 °C sample presents, at 5 K, a magnetic moment of 73 emu/g and 66 emu/g at 300 K. • Heat-treatment promotes the formation of lithium ferrate and hematite, decreasing the magnetic moment. - Abstract: Lithium ferrite (LiFe{sub 5}O{sub 8}) is an attractive material for several potential technological applications. Critical to such attractiveness are its physical properties, such as high Curie temperature, square hysteresis loop and high magnetization. Knowing that the properties of these crystals depend on the preparation method and raw materials, in this work LiFe{sub 5}O{sub 8} crystallites were obtained by controlled heat-treatments, between 200 and 1400 °C, of homogeneous Li{sub 2}O-Fe{sub 2}O{sub 3} powders prepared by wet ball-milling method and using lithium and iron nitrates as raw materials. LiFe{sub 5}O{sub 8} crystal phase was formed through heat-treatments at temperatures above 500 °C. At higher temperatures the formation of lithium ferrate and hematite is promoted, leading to a decrease in the magnetic moment. Heat-treated the sample at 1200 °C results in the highest levels of magnetic saturation, presenting a magnetic moment of 73 emu/g at 5 K and 66 emu/g at 300 K, respectively.

  4. Role of the nanocrystallinity on the chemical ordering of Co(x)Pt(100-x) nanocrystals synthesized by wet chemistry.

    Science.gov (United States)

    Kameche, Farid; Ngo, Anh-Tu; Salzemann, Caroline; Cordeiro, Marco; Sutter, Eli; Petit, Christophe

    2015-11-14

    Co(x)Pt(100-x) nanoalloys have been synthesized by two different chemical processes either at high or at low temperature. Their physical properties and the order/disorder phase transition induced by annealing have been investigated depending on the route of synthesis. It is demonstrated that the chemical synthesis at high temperature allows stabilization of the fcc structure of the native nanoalloys while the soft chemical approach yields mainly poly or non crystalline structure. As a result the approach of the order/disorder phase transition is strongly modified as observed by high-resolution transmission electron microscopy (HR-TEM) studies performed during in situ annealing of the different nanoalloys. The control of the nanocrystallinity leads to significant decrease in the chemical ordering temperature as the ordered structure is observed at temperatures as low as 420 °C. This in turn preserves the individual nanocrystals and prevents their coalescence usually observed during the annealing necessary for the transition to an ordered phase.

  5. Synthesis of Coral-Like, Straw-Tied-Like, and Flower-Like Antimony Sulfides by a Facile Wet-Chemical Method

    Directory of Open Access Journals (Sweden)

    Jutarat Kavinchan

    2013-01-01

    Full Text Available Antimony sulfide (Sb2S3 was successfully synthesized from antimony chloride (SbCl3 and sodium thiosulfate pentahydrate (Na2S2O3·5H2O in ethylene glycol (EG without using any template by a facile wet-chemical method. X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM show that the products were orthorhombic Sb2S3 nanorods forming the coral-like, straw-tied-like, and flower-like architectures with the nanorods growing along the [001] direction. The energy gap (Eg was determined by UV-visible absorption to be 1.52 eV.

  6. Recovery of phosphorus and aluminium from sewage sludge ash by a new wet chemical elution process (SESAL-Phos-recovery process).

    Science.gov (United States)

    Petzet, S; Peplinski, B; Bodkhe, S Y; Cornel, P

    2011-01-01

    The potential of a new wet chemical process for phosphorus and aluminium recovery from sewage sludge ash by sequential elution with acidic and alkaline solutions has been investigated: SESAL-Phos (sequential elution of sewage sludge ash for aluminium and phosphorus recovery). Its most innovative aspect is an acidic pre-treatment step in which calcium is leached from the sewage sludge ash. Thus the percentage of alkaline soluble aluminium phosphates is increased from 20 to 67%. This aluminium phosphate is then dissolved in alkali. Subsequently, the dissolved phosphorus is precipitated as calcium phosphate with low heavy metal content and recovered from the alkaline solution. Dissolved aluminium is recovered and may be reused as a precipitant in wastewater treatment plants.

  7. Controllable Shrinking of Glass Capillary Nanopores Down to sub-10 nm by Wet-Chemical Silanization for Signal-Enhanced DNA Translocation.

    Science.gov (United States)

    Xu, Xiaolong; Li, Chuanping; Zhou, Ya; Jin, Yongdong

    2017-10-27

    Diameter is a major concern for nanopore based sensing. However, directly pulling glass capillary nanopore with diameter down to sub-10 nm is very difficult. So, post treatment is sometimes necessary. Herein, we demonstrate a facile and effective wet-chemical method to shrink the diameter of glass capillary nanopore from several tens of nanometers to sub-10 nm by disodium silicate hydrolysis. Its benefits for DNA translocation are investigated. The shrinking of glass capillary nanopore not only slows down DNA translocation, but also enhances DNA translocation signal and signal-to-noise ratio significantly (102.9 for 6.4 nm glass nanopore, superior than 15 for a 3 nm silicon nitride nanopore). It also affects DNA translocation behaviors, making the approach and glass capillary nanopore platform promising for DNA translocation studies.

  8. Toward intrinsic graphene surfaces: a systematic study on thermal annealing and wet-chemical treatment of SiO2-supported graphene devices.

    Science.gov (United States)

    Cheng, Zengguang; Zhou, Qiaoyu; Wang, Chenxuan; Li, Qiang; Wang, Chen; Fang, Ying

    2011-02-09

    By combining atomic force microscopy and trans-port measurements, we systematically investigated effects of thermal annealing on surface morphologies and electrical properties of single-layer graphene devices fabricated by electron beam lithography on silicon oxide (SiO(2)) substrates. Thermal treatment above 300 °C in vacuum was required to effectively remove resist residues on graphene surfaces. However, annealing at high temperature was found to concomitantly bring graphene in close contact with SiO(2) substrates and induce increased coupling between them, which leads to heavy hole doping and severe degradation of mobilities in graphene devices. To address this problem, a wet-chemical approach employing chloroform was developed in our study, which was shown to enable both intrinsic surfaces and enhanced electrical properties of graphene devices. Upon the recovery of intrinsic surfaces of graphene, the adsorption and assisted fibrillation of amyloid β-peptide (Aβ1-42) on graphene were electrically measured in real time.

  9. Surface state modulation through wet chemical treatment as a route to controlling the electrical properties of ZnO nanowire arrays investigated with XPS

    International Nuclear Information System (INIS)

    Lord, Alex M.; Maffeis, Thierry G.; Allen, Martin W.; Morgan, David; Davies, Philip R.; Jones, Daniel R.; Evans, Jonathan E.; Smith, Nathan A.; Wilks, Steve P.

    2014-01-01

    Highlights: • Direct measurement of the surface band bending exhibited by ZnO nanowires using monochromatic XPS. • Modulation of the surface depletion region using wet chemical treatment (EtOH, H 2 O 2 ). • The measured surface potential barrier agrees with electrical measurements of individual nanowires. • H 2 O 2 depletes the nanowire of charge carriers while EtOH donates electrons at the surface. • EtOH has the effect of restoring the surface potential barrier of oxidised nanowires. - Abstract: ZnO is a wide bandgap semiconductor that has many potential applications including solar cell electrodes, transparent thin film transistors and gas/biological sensors. Since the surfaces of ZnO materials have no amorphous or oxidised layers, they are very environmentally sensitive, making control of their semiconductor properties challenging. In particular, the electronic properties of ZnO nanostructures are dominated by surface effects while surface conduction layers have been observed in thin films and bulk crystals. Therefore, the ability to use the ZnO materials in a controlled way depends on the development of simple techniques to modulate their surface electronic properties. Here, we use monochromatic x-ray photoelectron spectroscopy (XPS) to investigate the use of different wet chemical treatments (EtOH, H 2 O 2 ) to control the electronic properties of ZnO nanowires by modulating the surface depletion region. The valence band and core level XPS spectra are used to explore the relationship between the surface chemistry of the nanowires and the surface band bending

  10. An Overt Chemical Protective Garment Reduces Thermal Strain Compared with a Covert Garment in Warm-Wet but Not Hot-Dry Environments

    Directory of Open Access Journals (Sweden)

    Matthew J. Maley

    2017-11-01

    Full Text Available Objectives: A commercial chemical, biological, radiological and nuclear (CBRN protective covert garment has recently been developed with the aim of reducing thermal strain. A covert CBRN protective layer can be worn under other clothing, with equipment added for full chemical protection when needed. However, it is unknown whether the covert garment offers any alleviation to thermal strain during work compared with a traditional overt ensemble. Therefore, the aim of this study was to compare thermal strain and work tolerance times during work in an overt and covert ensemble offering the same level of CBRN protection.Methods: Eleven male participants wore an overt (OVERT or covert (COVERT CBRN ensemble and walked (4 km·h−1, 1% grade for a maximum of 120 min in either a wet bulb globe temperature [WBGT] of 21, 30, or 37°C (Neutral, WarmWet and HotDry, respectively. The trials were ceased if the participants' gastrointestinal temperature reached 39°C, heart rate reached 90% of maximum, walking time reached 120 min or due to self-termination.Results: All participants completed 120 min of walking in Neutral. Work tolerance time was greater in OVERT compared with COVERT in WarmWet (P < 0.001, 116.5[9.9] vs. 88.9[12.2] min, respectively, though this order was reversed in HotDry (P = 0.003, 37.3[5.3] vs. 48.4[4.6] min, respectively. The rate of change in mean body temperature and mean skin temperature was greater in COVERT (0.025[0.004] and 0.045[0.010]°C·min−1, respectively compared with OVERT (0.014[0.004] and 0.027[0.007]°C·min−1, respectively in WarmWet (P < 0.001 and P = 0.028, respectively. However, the rate of change in mean body temperature and mean skin temperature was greater in OVERT (0.068[0.010] and 0.170[0.026]°C·min−1, respectively compared with COVERT (0.059[0.004] and 0.120[0.017]°C·min−1, respectively in HotDry (P = 0.002 and P < 0.001, respectively. Thermal sensation, thermal comfort, and ratings of perceived

  11. Preparation of polymeric biomaterials with the aid of radiation-chemical methods

    International Nuclear Information System (INIS)

    Kabanov, Vitalii Ya

    1998-01-01

    The results of the application of radiation-chemical methods for the preparation of polymeric biomaterials are surveyed and treated systematically. The characteristic features of these methods and their advantages and disadvantages are indicated. The properties of polymeric biomaterials prepared using ionising radiation are examined. Particular attention is devoted to studies carried out during the last 10-15 years. The bibliography includes 492 references.

  12. Creating gradient wetting surfaces via electroless displacement of zinc-coated carbon steel by nickel ions

    Science.gov (United States)

    Xu, Chang; Liu, Huicong; Liang, Weitao; Zhu, Liqun; Li, Weiping; Chen, Haining

    2018-03-01

    Gradient wetting surfaces are getting increasing attention due to their wide application in multiple fields such as droplet movement and biosorption. However, the fabrication processes of full gradient wetting surfaces are still complex and costly. In present work, a facile and low-cost chemical immersion method was used to create a full gradient wetting surface. By controlling the displacement time in Ni2+ solution, the prepared surfaces perform hydrophilic to superhydrophilic. After being modified by stearic acid, the gradient hydrophilic surfaces convert into hydrophobic. The surface morphology, composition, and wetting behaviors of the as-prepared surfaces were systematically studied and discussed. The gradient wetting property could be attributed to the change in microroughness and surface energy. In addition, these surfaces also exhibited excellent self-cleaning and wax prevention properties. Furthermore, high stability and corrosion resistance were also found for these surfaces, which further highlight their promising practical applications in many fields.

  13. Physical, Chemical, and Biological Properties of Soil under Decaying Wood in a Tropical Wet Forest in Puerto Rico

    Science.gov (United States)

    Marcela Zalamea; Grizelle Gonzalez; D. Jean Lodge

    2016-01-01

    Decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients. However, at micro scales, what is the effect of decaying logs on the physical, chemical,and biotic characteristics of the soil underneath? We took samples from a 0 to 5 cm depth under and a 50 cm distance away from decaying logs (Dacryodes excelsa and Swietenia...

  14. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Stefanie M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Lauermann, Iver, E-mail: Iver.lauermann@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2010-02-15

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  15. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    International Nuclear Information System (INIS)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-01-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  16. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Science.gov (United States)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-02-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  17. [Study on Content Determination of Lead and Arsenic in Four Traditional Tibetan Medicine Prescription Preparations by Wet Digestion Flow Injection-Hydride Generation-Atomic Absorption Spectrometry].

    Science.gov (United States)

    Zheng, Zhi-yuan; Du, Yu-zhi; Zhang, Ming; Yu, Ming-jie; Li, Cen; Yang, Hong-xia; Zhao, Jing; Xia, Zheng-hua; Wei, Li-xin

    2015-04-01

    Four common traditional tibetan medicine prescription preparations "Anzhijinghuasan, Dangzuo, Renqingchangjue and Rannasangpei" in tibetan areas were selected as study objects in the present study. The purpose was to try to establish a kind of wet digestion and flow injection-hydride generation-atomic absorption spectrometry (FI-HAAS) associated analysis method for the content determinations of lead and arsenic in traditional tibetan medicine under optimized digestion and measurement conditions and determine their contents accurately. Under these optimum operating conditions, experimental results were as follows. The detection limits for lead and arsenic were 0.067 and 0.012 µg · mL(-1) respectively. The quantification limits for lead and arsenic were 0.22 and 0.041 µg · mL(-1) respectively. The linear ranges for lead and arsenic were 25-1,600 ng · mL(-1) (r = 0.9995) and 12.5-800 ng · mL(-1) (r = 0.9994) respectively. The degrees of precision(RSD) for lead and arsenic were 2.0% and 3.2% respectively. The recovery rates for lead and arsenic were 98.00%-99.98% and 96.67%-99.87% respectively. The content determination results of lead and arsenic in four traditional tibetan medicine prescription preparations were as fol- lows. The contents of lead and arsenic in Anzhijinghuasan are 0.63-0.67 µg · g(-1) and 0.32-0.33 µg · g(-1) in Anzhijinghua- san, 42.92-43.36 µg · g(-1) and 24.67-25.87 µg · g(-1) in Dangzuo, 1,611. 39-1,631.36 µg · g(-1) and 926.76-956.52 µg- g(-1) in Renqing Changjue, and 1,102.28-1,119.127 µg-g(-1) and 509.96-516.87 µg · g(-1) in Rannasangpei, respectively. This study established a method for content determination of lead and arsenic in traditional tibetan medicine, and determined the content levels of lead and arsenic in four tibetan medicine-prescription preparations accurately. In addition, these results also provide the basis for the safe and effective use of those medicines in clinic.

  18. Textural and chemical properties of zinc chloride activated carbons prepared from pistachio-nut shells

    International Nuclear Information System (INIS)

    Yang Ting; Lua, Aik Chong

    2006-01-01

    The effects of activation temperature on the textural and chemical properties of the activated carbons prepared from pistachio-nut shells using zinc chloride activation under both inert nitrogen gas atmosphere and vacuum condition were studied. Relatively low temperature of 400 deg. C was beneficial for the development of pore structures. Too high an activation temperature would lead to sintering of volatiles and shrinkage of the carbon structure. The microstructures and microcrystallinity of the activated carbons prepared were examined by scanning electron microscope and powder X-ray diffraction techniques, respectively, while Fourier transform infrared spectra determined the changes in the surface functional groups at the various stages of preparation

  19. Textural and chemical properties of zinc chloride activated carbons prepared from pistachio-nut shells

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Yang [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Lua, Aik Chong [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2006-12-10

    The effects of activation temperature on the textural and chemical properties of the activated carbons prepared from pistachio-nut shells using zinc chloride activation under both inert nitrogen gas atmosphere and vacuum condition were studied. Relatively low temperature of 400 deg. C was beneficial for the development of pore structures. Too high an activation temperature would lead to sintering of volatiles and shrinkage of the carbon structure. The microstructures and microcrystallinity of the activated carbons prepared were examined by scanning electron microscope and powder X-ray diffraction techniques, respectively, while Fourier transform infrared spectra determined the changes in the surface functional groups at the various stages of preparation.

  20. Exploring the Potential of Different-Sized Supported Subnanometer Pt Clusters as Catalysts for Wet Chemical Applications

    KAUST Repository

    Rondelli, Manuel

    2017-05-10

    The use of physicochemical preparation techniques of metal clusters in the ultrahigh vacuum (UHV) allows for high control of cluster nuclearity and size distribution for fundamental studies in catalysis. Surprisingly, the potential of these systems as catalysts for organic chemistry transformations in solution has not been explored. To this end, single Pt atoms and Pt clusters with two narrow size distributions were prepared in the UHV and applied for the hydrogenation of p-chloronitrobenzene to p-chloroaniline in ethanol. Following the observation of very high catalytic turnovers (approaching the million molecules of p-nitroaniline formed per Pt cluster) and of size-dependent activity, this work addresses fundamental questions with respect to the suitability of these systems as heterogeneous catalysts for the conversion of solution-phase reagents. For this purpose, we employ scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS) characterization before and after reaction to assess the stability of the clusters on the support and the question of heterogeneity versus homogeneity in the catalytic process.

  1. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method.

    Science.gov (United States)

    Barbosa, Michelle C; Messmer, Nigel R; Brazil, Tayra R; Marciano, Fernanda R; Lobo, Anderson O

    2013-07-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. [Preparation of the database and the homepage on chemical accidents relating to health hazard].

    Science.gov (United States)

    Yamamoto, M; Morita, M; Kaminuma, T

    1998-01-01

    We collected the data on accidents due to chemicals occurred in Japan, and prepared the database. We also set up the World Wide Web homepage containing the explanation on accidents due to chemicals and the retrieval page for the database. We designed the retrieval page so that users can search the data from keywords such as chemicals (e.g. chlorine gas, hydrogen sulfide, pesticides), places (e.g. home, factory, vehicles, tank), causes (e.g. reaction, leakage, exhaust gas) and others (e.g. cleaning, painting, transportation).

  3. Epitaxial ternary nitride thin films prepared by a chemical solution method

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Hongmei [Los Alamos National Laboratory; Feldmann, David M [Los Alamos National Laboratory; Wang, Haiyan [TEXAS A& M; Bi, Zhenxing [TEXAS A& M

    2008-01-01

    It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.

  4. Dielectric behaviour of MgFe2O4 prepared from chemically ...

    Indian Academy of Sciences (India)

    Unknown

    dielectric loss factor. 1. Introduction ... such production of ferrites in year 2005 would be of about. 10,50,000 MTPY. ... factors such as method of preparation, chemical compo- sition, and ..... (VII) Low content of polarizable Fe2+ ions on the octa-.

  5. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method

    International Nuclear Information System (INIS)

    Barbosa, Michelle C.; Messmer, Nigel R.; Brazil, Tayra R.; Marciano, Fernanda R.; Lobo, Anderson O.

    2013-01-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. - Highlights: ► Nanohydroxyapatite powders were produced via aqueous precipitation. ► Three methodologies were compared, such as: dropwise, mixture and ultrasound irradiation (UI). ► Analysis found strong connections between UI and the crystallization process

  6. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Michelle C.; Messmer, Nigel R.; Brazil, Tayra R.; Marciano, Fernanda R.; Lobo, Anderson O., E-mail: loboao@yahoo.com

    2013-07-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. - Highlights: ► Nanohydroxyapatite powders were produced via aqueous precipitation. ► Three methodologies were compared, such as: dropwise, mixture and ultrasound irradiation (UI). ► Analysis found strong connections between UI and the crystallization process.

  7. Structural and mechanical characterization of boron doped biphasic calcium phosphate produced by wet chemical method and subsequent thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Albayrak, Onder, E-mail: albayrakonder@mersin.edu.tr

    2016-03-15

    In the current study, boron doped biphasic calcium phosphate bioceramics consisting of a mixture of boron doped hydroxyapatite (BHA) and beta tricalcium phosphate (β-TCP) of varying BHA/β-TCP ratios were obtained after sintering stage. The effects of varying boron contents and different sintering temperatures on the BHA/β-TCP ratios and on the sinterability of the final products were investigated. Particle sizes and morphologies of the obtained precipitates were determined using SEM. XRD and FTIR investigation were conducted to detect the boron formation in the structure of HA and quantitative analysis was performed to determine the BHA/β-TCP ratio before and after sintering stage. In order to determine the sinterability of the obtained powders, pellets were prepared and sintered; the rates of densification were calculated and obtained results were correlated by SEM images. Also Vickers microhardness values of the sintered samples were determined. The experimental results verified that boron doped hydroxyapatite powders were obtained after sintering stage and the structure consists of a mixture of BHA and β-TCP. As the boron content used in the precipitation stage increases, β-TCP content of the BHA/β-TCP ratio increases but sinterability, density and microhardness deteriorate. As the sintering temperature increases, β-TCP content, density and microhardness of the samples increase and sinterability improves. - Highlights: • This is the first paper about boron doped biphasic calcium phosphate bioceramics. • Boron doping affects the structural and mechanical properties. • BHA/β-TCP ratio can be adjustable with boron content and sintering temperature.

  8. Mars Surveyor Program '01 Mars Environmental Compatibility Assessment wet chemistry lab: a sensor array for chemical analysis of the Martian soil

    Science.gov (United States)

    Kounaves, Samuel P.; Lukow, Stefan R.; Comeau, Brian P.; Hecht, Michael H.; Grannan-Feldman, Sabrina M.; Manatt, Ken; West, Steven J.; Wen, Xiaowen; Frant, Martin; Gillette, Tim

    2003-01-01

    The Mars Environmental Compatibility Assessment (MECA) instrument was designed, built, and flight qualified for the now canceled MSP (Mars Surveyor Program) '01 Lander. The MECA package consisted of a microscope, electrometer, material patch plates, and a wet chemistry laboratory (WCL). The primary goal of MECA was to analyze the Martian soil (regolith) for possible hazards to future astronauts and to provide a better understanding of Martian regolith geochemistry. The purpose of the WCL was to analyze for a range of soluble ionic chemical species and electrochemical parameters. The heart of the WCL was a sensor array of electrochemically based ion-selective electrodes (ISE). After 20 months storage at -23 degrees C and subsequent extended freeze/thawing cycles, WCL sensors were evaluated to determine both their physical durability and analytical responses. A fractional factorial calibration of the sensors was used to obtain slope, intercept, and all necessary selectivity coefficients simultaneously for selected ISEs. This calibration was used to model five cation and three anion sensors. These data were subsequently used to determine concentrations of several ions in two soil leachate simulants (based on terrestrial seawater and hypothesized Mars brine) and four actual soil samples. The WCL results were compared to simulant and soil samples using ion chromatography and inductively coupled plasma optical emission spectroscopy. The results showed that flight qualification and prolonged low-temperature storage conditions had minimal effects on the sensors. In addition, the analytical optimization method provided quantitative and qualitative data that could be used to accurately identify the chemical composition of the simulants and soils. The WCL has the ability to provide data that can be used to "read" the chemical, geological, and climatic history of Mars, as well as the potential habitability of its regolith.

  9. Long term effects of wet site timber harvesting and site preparation on soil properties and loblolly pine (Pinus taeda L.) productivity in the lower Atlantic Coastal Plain

    OpenAIRE

    Neaves III, Charles Mitchell

    2017-01-01

    Short term studies have suggested that ground based timber harvesting on wet sites can alter soil properties and inhibit early survival and growth of seedlings. Persistence of such negative effects may translate to losses in forest productivity over a rotation. During the fall and winter of 1989, numerous salvage logging operations were conducted during high soil moisture conditions on wet pine flats in the lower coastal plain of South Carolina following Hurricane Hugo. A long-term experim...

  10. Preparation of InAs(0 0 1) surface for spin injection via a chemical route

    International Nuclear Information System (INIS)

    Singh, L J; Oliver, R A; Barber, Z H; Eustace, D A; McComb, D W; Clowes, S K; Gilbertson, A M; Magnus, F; Branford, W R; Cohen, L F; Buckle, L; Buckle, P D; Ashley, T

    2007-01-01

    A wet chemical surface treatment for InAs epilayers is investigated to remove the native semiconductor oxide prior to growth of a MgO tunnel barrier and Co ferromagnetic electrode by dc magnetron sputtering. Use of a HCl etch followed by (NH 4 ) 2 S as the pre-growth surface treatment resulted in pinhole-like features in the tunnel barrier, as observed by conducting atomic force microscopy, but this detrimental effect is avoided if the etch procedure is repeated twice. High resolution transmission electron microscopy revealed that the etched samples had uniform tunnel barriers and reducing the growth temperature of the barrier from 200 to 100 0 C significantly improved the abruptness of the semiconductor/barrier interface. Electrical characterization of barrier properties illustrated that all the etched samples showed parabolic differential conductance curves indicative of tunnelling behaviour at 300 K

  11. Pore Scale Investigation of Wettability Alteration Through Chemically-Tuned Waterflooding in Oil-Wet Carbonate Rocks Using X-Ray Micro-Ct Imaging

    Science.gov (United States)

    Tawfik, M. S.; Karpyn, Z.

    2017-12-01

    Carbonate reservoirs host more than half of the remaining oil reserves worldwide. Due to their complex pore structure and intermediate to oil-wet nature, it is challenging to produce the remaining oil from these formations. For two decades, chemically tuned waterflooding (CTWF) has gained the attention of many researchers. Experimental, numerical, and field studies suggest that changes in ion composition of injected brine can increase oil recovery in carbonate reservoirs via wettability alteration. However, previous studies explaining the improvement in oil recovery by wettability alteration deduce wettability based on indirect measurements, including sessile drop contact angle measurements on polished rocks, relative permeability, chromatographic separation of SCN- and potential determining ions (PDIs), etc. CTWF literature offers no direct measurement of wettability alteration at the pore scale. This study proposes a direct pore-scale measurement of changes in interfacial curvatures before and after CTWF. Micro-coreflood experiments are performed to investigate the effect of injection brine salinity, ion composition and temperature on rock wettability at the pore scale. X-ray micro-CT scanning is used to obtain 3D image sets to calculate in-situ contact angle distributions. The study also aims to find a correlation between the magnitude of improvement in oil recovery at the macro-scale and the corresponding contact angle distribution at the pore-scale at different experimental conditions. Hence, macro-scale coreflood experiments are performed using the same conditions as the micro-corefloods. Macro-scale coreflood experiments have shown that brines with higher concentration of Ca2+, Mg2+ and SO42- ions have higher recoveries compared to standard seawater. This translates to wettability alteration into a more intermediate-wet state. This study enhances the understanding of the pore-scale physico-chemical mechanisms controlling wettability alteration via CTWF

  12. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  13. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    International Nuclear Information System (INIS)

    Verma, Pallavi; Maire, Pascal; Novak, Petr

    2011-01-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH 2 ) 3 OCO 2 Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C 6 H 4 NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C 6 H 4 CH 2 OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  14. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Pallavi; Maire, Pascal [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland); Novak, Petr, E-mail: petr.novak@psi.c [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland)

    2011-04-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH{sub 2}){sub 3}OCO{sub 2}Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C{sub 6}H{sub 4}NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C{sub 6}H{sub 4}CH{sub 2}OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  15. Wet cutting

    Energy Technology Data Exchange (ETDEWEB)

    Hole, B. [IMC Technical Services (United Kingdom)

    1999-08-01

    Continuous miners create dust and methane problems in underground coal mining. Control has usually been achieved using ventilation techniques as experiments with water based suppression have led to flooding and electrical problems. Recent experience in the US has led to renewed interest in wet head systems. This paper describes tests of the Hydraphase system by IMC Technologies. Ventilation around the cutting zone, quenching of hot ignition sources, dust suppression, the surface trial gallery tests, the performance of the cutting bed, and flow of air and methane around the cutting head are reviewed. 1 ref., 2 figs., 2 photos.

  16. Effect of biological and chemical preparations on peroxidase activity in leaves of tomato plants

    Directory of Open Access Journals (Sweden)

    Yulia Kolomiets

    2016-10-01

    Full Text Available In terms of treating tomato variety Chaika with chemical preparations with active substances if aluminum phosphate, 570 g/l + phosphorous acid 80 g/,l and mankotseb in concentration of 640 g/kg, the maximum increase in peroxidase activity in leaves of plants was observed in12 hours. In terms of use of biological preparations based on living cells Bacillus subtilis and Azotobacter chroococcum its activity was maximum in 24 hours and ranged from 77.7 to 112.7 un.mg-1•s-1

  17. Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition

    Science.gov (United States)

    2017-09-30

    Report: Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer ...Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition Report Term: 0-Other Email: pcappillino... Layer Electroless Deposition (ALED, Figure 1) is the ability to tune growth mechanism, hence growth morphology, by altering conditions. In this

  18. The usability of ark clam shell (Anadara granosa) as calcium precursor to produce hydroxyapatite nanoparticle via wet chemical precipitate method in various sintering temperature.

    Science.gov (United States)

    Khiri, Mohammad Zulhasif Ahmad; Matori, Khamirul Amin; Zainuddin, Norhazlin; Abdullah, Che Azurahanim Che; Alassan, Zarifah Nadakkavil; Baharuddin, Nur Fadilah; Zaid, Mohd Hafiz Mohd

    2016-01-01

    This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries .

  19. Wet chemical synthesis and luminescence in Ca5(PO4)3M:Eu2+ (M = Br, I) phosphors for solid state lighting

    Science.gov (United States)

    Mungmode, C. D.; Gahane, D. H.; Moharil, S. V.

    2018-05-01

    A simple wet chemical synthesis of Eu2+ activated Ca5(PO4)3Br and Ca5(PO4)3I phosphors and their photoluminescence is reported. Formation of Ca5(PO4)3Br is confirmed by X-ray diffraction (XRD). Synthesized phosphors are analyzed for photoluminescence (PL) spectrum. A bright blue emission is observed when phosphors are excited by near Ultra Violet (nUV) radiations. Photoluminescence emission spectrum for (Ca0.985Eu0.015)5(PO4)3Br is centered at 457 nm and for (Ca0.985Eu0.015)5(PO4)3 I it peaks at 455 nm when excited by 365 nm near UV radiation. Eu2+ luminescence in Ca5(PO4)3Br is reported for the first time. The phosphors can be efficiently excited by nUV radiations. This shows that phosphors may be used as blue phosphor in pcLED for Solid State Lighting.

  20. Improvement of the optical quality of site-controlled InAs quantum dots by a double stack growth technique in wet-chemically etched holes

    Energy Technology Data Exchange (ETDEWEB)

    Pfau, Tino Johannes; Gushterov, Aleksander; Reithmaier, Johann-Peter [Technische Physik, INA, Universitaet Kassel (Germany); Cestier, Isabelle; Eisenstein, Gadi [Electrical Engineering Dept., Technion, Haifa (Israel); Linder, Evgany; Gershoni, David [Solid State Institute and Physics Dept., Technion, Haifa (Israel)

    2010-07-01

    The optimization of the wet-chemically etching of holes and a special MBE growth stack technique allows enlarging the site-control of low density InAs QDs on GaAs substrates up to a buffer layer thickness of 55 nm. The strain of InAs QDs, grown in the etched holes, reduces the hole closing, so that a pre-patterned surface is conserved for the second QD layer. The distance of 50 nm GaAs between the two QD layers exceeds drastically the maximum vertical alignment based on pure strain coupling (20 nm). Compared to stacks with several QD layers, this method avoids electronic coupling between the different QD layers and reduces the problems to distinguish the dots of different layers optically. Confocal microphotoluminescence reveals a significant diminution of the low temperature photoluminescence linewidth of the second InAs QD layer to an average value of 505{+-}53 {mu}eV and a minimum width of 460 {mu}eV compared to 2 to 4 meV for QDs grown on thin buffer layers. The increase of the buffer layer thickness decreases the influence of the surface defects caused by prepatterning.

  1. Growth of ZnO nanowire arrays directly onto Si via substrate topographical adjustments using both wet chemical and dry etching methods

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Nathan A., E-mail: 523615@swansea.ac.uk [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom); Evans, Jon E.; Jones, Daniel R. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Lord, Alex M. [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Wilks, S.P. [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom)

    2015-03-15

    Highlights: • Arrays of catalyst-free ZnO NWs have been grown by CVD without seed layers on Si. • Si surface topography was altered by substrate etching, resulting in NW growth. • XPS analysis shows growth is related to topography and not surface contamination. • Using e-beam lithography with etching, selective nanowire growth is demonstrated. • Electrical measurements on the arrays show improved conduction through the Si. - Abstract: Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

  2. Structural and morphological study of Zn0.9Mn0.05Fe0.05O synthesized by sol-gel wet chemical precipitation route

    Science.gov (United States)

    Jain, S. K.; Dolia, S. N.; Choudhary, B. L.; Prashant, B. L.

    2018-04-01

    Transition metal substituted Zinc oxide (ZnO) has drawn a great deal of attention due to its excellent properties. Zn0.9Mn0.05Fe0.05O sample synthesized was by Sol-gel wet chemical precipitation route at temperature 350°C. The crystallinity and the structure of Zn0.9Mn0.05Fe0.05O was determined by X-ray diffraction by Cu-Kα radiations operated at 40kV and 35mA in the range of 20° to 80°. The pattern gets indexed in wurtzite (hexagonal) structure with lattice constants a=b=3.2525Å and c=5.2071Å and approves the single phase material with no impurity. The values of particle size assessed by Debye Scherer’s (DS) formula lie in the range of 13nm to 33nm indicating the nano-crystalline nature of the sample. The morphological analysis of the sample was performed by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) measurements. The observed size of Zn0.9Mn0.05Fe0.05O nanoparticles by TEM micrograph exhibits the similar trend with the size calculated by Debye-Scherer formula. TEM image show the irregular shape of the nanoparticles and particle size lies in the range of 10-35nm. Similar to SEM image, the slight agglomeration of the nanoparticles have been observed from TEM.

  3. Wet chemical treatment of boron doped emitters on n-type (1 0 0) c-Si prior to amorphous silicon passivation

    Energy Technology Data Exchange (ETDEWEB)

    Meddeb, H., E-mail: hosny.meddeb@gmail.com [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); University of Carthage, Faculty of Sciences of Bizerta (Tunisia); Bearda, T.; Recaman Payo, M.; Abdelwahab, I. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Abdulraheem, Y. [Electrical Engineering Department, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, 13060 Safat (Kuwait); Ezzaouia, H. [Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); Gordon, I.; Szlufcik, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Poortmans, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering (ESAT), K.U. Leuven, 3001 Leuven (Belgium); Faculty of Sciences, University of Hasselt, Martelarenlaan 42, 3500 Hasselt (Belgium)

    2015-02-15

    Highlights: • The influence of the cleaning process using different HF-based cleaning on the amorphous silicon passivation of homojunction boron doped emitters is analyzed. • The effect of boron doping level on surface characteristics after wet chemical cleaning: For heavily doped surfaces, the reduction in contact angle was less pronounced, which proves that such surfaces are more resistant to oxide formation and remain hydrophobic for a longer time. In the case of low HF concentration, XPS measurements show higher oxygen concentrations for samples with higher doping level, probably due to the incomplete removal of the native oxide. • Higher effective lifetime is achieved at lower doping for all considered different chemical pre-treatments. • A post-deposition annealing improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below. • The dominance of Auger recombination over other type of B-induced defects on lifetime quality in the case of our p+ emitter. - Abstract: The influence of the cleaning process on the amorphous silicon passivation of homojunction emitters is investigated. A significant variation in the passivation quality following different cleaning sequences is not observed, even though differences in cleaning performance are evident. These results point out the effectiveness of our cleaning treatment and provide a hydrogen termination for intrinsic amorphous silicon passivation. A post-deposition treatment improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below.

  4. Production of radionuclides and preparation of labelled compounds. Nuclear chemical technology

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    A general review is presented of methods of producing radionuclide preparations and labelled compounds, such as their production from natural raw materials, from a nuclear reactor, a particle accelerator, and using radioisotope generators. Also described are the fundamental kinetic relations of nuclear reactions. Basic methods are surveyed of obtaining labelled compounds by chemical synthesis, biosynthesis, exchange reactions, recoil reactions, by the Wilzbach method and the Szillard-Chalmers reaction. (L.K.)

  5. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae [Chungbuk National Univ., Chungju (Korea, Republic of)

    2013-06-15

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m{sup 2}/g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn{sub 2}O{sub 4}, LiCoO{sub 2} as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF{sub 6}, TEABF{sub 4}) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn{sub 2}O{sub 4}/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

  6. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    International Nuclear Information System (INIS)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae

    2013-01-01

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m 2 /g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn 2 O 4 , LiCoO 2 as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF 6 , TEABF 4 ) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn 2 O 4 /AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg

  7. Influence of physical and chemical polymer-filler bonds on wet skid resistance and related properties of passenger car tire treads

    NARCIS (Netherlands)

    Cichomski, E.M.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.; Tolpekina, T.V.; Schultz, S.M.

    2012-01-01

    Knowledge about the influence of rubber – filler interactions on the wet skid behavior of tire treads is insufficient, in order to quickly develop new compounds with improved wet skid performance. The rubber compound used for a tire tread is in fact a composite material of which the dynamic

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

    International Nuclear Information System (INIS)

    Shaji, S.; Garcia, L.V.; Loredo, S.L.; Krishnan, B.

    2017-01-01

    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_2S_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_2S_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_2S_3 thin films for optoelectronic applications.

  9. 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.

  10. Removal of Zn(II) and Hg(II) from aqueous solution on a carbonaceous sorbent chemically prepared from rice husk

    International Nuclear Information System (INIS)

    El-Shafey, E.I.

    2010-01-01

    A carbonaceous sorbent was prepared from rice husk via sulfuric acid treatment. Sorption of Zn(II) and Hg(II) from aqueous solution was studied varying time, pH, metal concentration, temperature and sorbent status (wet and dry). Zn(II) sorption was found fast reaching equilibrium within ∼2 h while Hg(II) sorption was slow reaching equilibrium within ∼120 h with better performance for the wet sorbent than for the dry. Kinetics data for both metals were found to follow pseudo-second order model. Sorption rate of both metals was enhanced with temperature rise. Activation energy, E a , for Zn(II) sorption, was ∼13.0 kJ/mol indicating a diffusion-controlled process ion exchange process, however, for Hg(II) sorption, E a was ∼54 kJ/mol indicating a chemically controlled process. Sorption of both metals was low at low pH and increased with pH increase. Sorption was much higher for Hg(II) than for Zn(II) with higher uptake for both metals by rising the temperature. Hg(II) was reduced to Hg(I) on the sorbent surface. This was confirmed from the identification of Hg 2 Cl 2 deposits on the sorbent surface by scanning electron microscopy and X-ray diffraction. However, no redox processes were observed in Zn(II) sorption. Sorption mechanism is discussed.

  11. Wet Oxidation of Maleic Acid by a Pumice Supported Copper (II ...

    African Journals Online (AJOL)

    Pumice supported Cu (II) Schiff base catalysts were prepared by surface chemical modification followed by complexation with Cu (II) acetate. The resulting materials were characterised by Diffuse Reflectance Fourier Transform Spectroscopy (DRIFTS) to confirm the modification. The materials were tested in a wet oxidation ...

  12. Effect of ultrasound treatment on the wet heating Maillard reaction between mung bean [Vigna radiate (L.)] protein isolates and glucose and on structural and physico-chemical properties of conjugates.

    Science.gov (United States)

    Wang, Zhongjiang; Han, Feifei; Sui, Xiaonan; Qi, Baokun; Yang, Yong; Zhang, Hui; Wang, Rui; Li, Yang; Jiang, Lianzhou

    2016-03-30

    The objective of this study was to determine the effect of ultrasound treatment on the wet heating Maillard reaction between mung bean protein isolates (MBPIs) and glucose, and on structural and physico-chemical properties of the conjugates. The degree of glycosylation of MBPI-glucose conjugates treated by ultrasound treatment and wet heating (MBPI-GUH) was higher than that of MBPI-glucose conjugates only treated by wet heating (MBPI-GH). Solubility, emulsification activity, emulsification stability and surface hydrophobicity of MBPI-GUH were higher than that of MBPI-GH. Grafted MBPIs had a lower content of α-helix and unordered coil, but a higher content of β-sheet and β-turn structure than MBPIs. No significant structural changes were observed in β-turn and random coil structure of MBPI-GUH, while α-helix content increased with ultrasonic time, and decreased at 300 W ultrasonic power with the increase of β-sheet. MBPI-GUH had a less compact tertiary structure compared to MBPI-GH and MBPI. Grafting MBPIs with glucose formed conjugates of higher molecular weight, while no significant changes were observed in electrophoresis profiles of MBPI-GUH. Ultrasound-assisted wet heating Maillard reaction between MBPIs and glucose could be a promising way to improve functional properties of MBPIs. © 2015 Society of Chemical Industry.

  13. High-throughput analysis for preparation, processing and analysis of TiO2 coatings on steel by chemical solution deposition

    International Nuclear Information System (INIS)

    Cuadrado Gil, Marcos; Van Driessche, Isabel; Van Gils, Sake; Lommens, Petra; Castelein, Pieter; De Buysser, Klaartje

    2012-01-01

    Highlights: ► High-throughput preparation of TiO 2 aqueous precursors. ► Analysis of stability and surface tension. ► Deposition of TiO 2 coatings. - Abstract: A high-throughput preparation, processing and analysis of titania coatings prepared by chemical solution deposition from water-based precursors at low temperature (≈250 °C) on two different types of steel substrates (Aluzinc® and bright annealed) is presented. The use of the high-throughput equipment allows fast preparation of multiple samples saving time, energy and material; and helps to test the scalability of the process. The process itself includes the use of IR curing for aqueous ceramic precursors and possibilities of using UV irradiation before the final sintering step. The IR curing method permits a much faster curing step compared to normal high temperature treatments in traditional convection devices (i.e., tube furnaces). The formulations, also prepared by high-throughput equipment, are found to be stable in the operational pH range of the substrates (6.5–8.5). Titanium alkoxides itself lack stability in pure water-based environments, but the presence of the different organic complexing agents prevents it from hydrolysis and precipitation reactions. The wetting interaction between the substrates and the various formulations is studied by the determination of the surface free energy of the substrates and the polar and dispersive components of the surface tension of the solutions. The mild temperature program used for preparation of the coatings however does not lead to the formation of pure crystalline material, necessary for the desired photocatalytic and super-hydrophilic behavior of these coatings. Nevertheless, some activity can be reported for these amorphous coatings by monitoring the discoloration of methylene blue in water under UV irradiation.

  14. Synthesis of ZnO micro-pompons by soft template-directed wet chemical method and their application in electrochemical biosensors

    International Nuclear Information System (INIS)

    Zhou, Yu; Wang, Lei; Ye, Zhizhen; Zhao, Minggang; Huang, Jingyun

    2014-01-01

    Highlights: •ZnO micro-pompons (MPs) are synthesized by a controlled soft template-directed route. •ZnO MPs are composed of radial robust nanowires built of numerous nanoparticles. •The structure is ideal for the immobilization of enzymes to maintain their activity. •ZnO MPs are favorable for electron transfer and liquid mobilization. •Good performance of H 2 O 2 biosensor indicates ZnO MPs are promising in biosensing. -- Abstract: ZnO micro-pompons are fabricated by a controlled synthesis route via a soft template-directed wet chemical method followed by a subsequent calcination in air. The achieved ZnO micro-pompons with several hundred micrometers in diameter are composed of a great number of robust nanowires built of numerous nanoparticles. This unique structure is accessible for enzymes to sequester or bind, and the tightly connected nanoparticles facilitate the transmission of electrons, what's more, the large spaces between the nanowires are favorable for the mobilization of the liquid with target substance. In addition, the high electron communication features of ZnO and the tightly connected nanoparticles of the structure also promote the electron transfer between the active sites of proteins and the electrode. The enzymatic electrode fabricated with Horseradish peroxidase immobilized on ZnO micro-pompons along with chitosan covering outside exhibits excellent response for detecting H 2 O 2 with a wide linear range of 0.2–3.4 mM and a high sensitivity of 1395.64 (μA/mM cm 2 ), indicating a great potential in fabricating electrochemical biosensors

  15. Preparation of activated Carbons from extracted waste biomass by chemical activation

    International Nuclear Information System (INIS)

    Toteva, V.; Nickolov, R.

    2013-01-01

    Full text: Novel biomass precursors for the production of activated carbons (ACs) were studied. ACs were prepared from extracted coffee husks and extracted spent ground coffee - separately or as mixtures with 10, 20 and 30 mass % Bulgarian lignite coal. Activation by potassium hydroxide was employed for all samples. The results obtained show that the surface and porous parameters of the ACs depend on the nature of the initial materials used. The specific surface areas (BET) and the microporosities of ACs obtained from extracted spent ground coffee mixed with 20 mass % Bulgarian lignite coals, are greater than those of the ACs from extracted coffee husks. It is likely that the reason for this result is the chemical composition of the precursors. The coffee husks have less lignin and more holocellulose. The latter undergoes more significant destructive changes in the process of chemical activation. On the contrary, waste ground coffee precursors contain more lignin and less holocellulose. As a result, after the chemical activation, the carbons prepared from extracted spent ground coffee exhibit better porous parameters and higher specific surface areas. key words: activated carbons, extraction, waste biomass

  16. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  17. 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......Cobalt oxide films were grown by Pulsed Injection Metal Organic Chemical Vapour Deposition (PI-MOCVD) using Co(acac)(3) (acac=acetylacetonate) precursor dissolved in toluene. The structure, morphology and growth rate of the layers deposited on silicon substrates were studied as a function......, to be used in Intermediate Temperature Solid Oxide Fuel Cells. (C) 2004 Elsevier B.V. All rights reserved....

  18. Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors.

    Science.gov (United States)

    Zappa, Dario; Bertuna, Angela; Comini, Elisabetta; Kaur, Navpreet; Poli, Nicola; Sberveglieri, Veronica; Sberveglieri, Giorgio

    2017-01-01

    Preparation and characterization of different metal oxide (NiO, WO 3 , ZnO, SnO 2 and Nb 2 O 5 ) nanostructures for chemical sensing are presented. p-Type (NiO) and n-type (WO 3 , SnO 2 , ZnO and Nb 2 O 5 ) metal oxide nanostructures were grown on alumina substrates using evaporation-condensation, thermal oxidation and hydrothermal techniques. Surface morphologies and crystal structures were investigated through scanning electron microscopy and Raman spectroscopy. Furthermore, different batches of sensors have been prepared, and their sensing performances towards carbon monoxide and nitrogen dioxide have been explored. Moreover, metal oxide nanowires have been integrated into an electronic nose and successfully applied to discriminate between drinking and contaminated water.

  19. Assessment of activated carbon prepared from corncob by chemical activation with phosphoric acid

    Directory of Open Access Journals (Sweden)

    Gamal O. El-Sayed

    2014-09-01

    Full Text Available Corncob, which is the main waste from corn agricultures in Egypt, has been used as a raw material for the preparation of different activated carbons. Activated carbons (ACs were prepared by chemical activation with concentrated H3PO4 acid; followed by pyrolysis at 400, 500 and 600 °C. Different ACs have been used for the removal of methylene blue (MB dye from aqueous solutions. Batch adsorption experiments were performed as a function of initial dye concentration, contact time, adsorbent dose and pH. Adsorption data were modeled using the Langmuir and Freundlich adsorption isotherms. Adsorption of MB on AC1 (R2=0.9868 and AC2 (R2=0.9810 followed Langmuir model with maximum monolayer sorption capacity of 28.65 and 17.57 mg/g, respectively. Adsorption onto AC3 was better fitted to Freundlich isotherm model (R2=0.9823.

  20. 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.)

  1. Protocols for the analytical characterization of therapeutic monoclonal antibodies. II - Enzymatic and chemical sample preparation.

    Science.gov (United States)

    Bobaly, Balazs; D'Atri, Valentina; Goyon, Alexandre; Colas, Olivier; Beck, Alain; Fekete, Szabolcs; Guillarme, Davy

    2017-08-15

    The analytical characterization of therapeutic monoclonal antibodies and related proteins usually incorporates various sample preparation methodologies. Indeed, quantitative and qualitative information can be enhanced by simplifying the sample, thanks to the removal of sources of heterogeneity (e.g. N-glycans) and/or by decreasing the molecular size of the tested protein by enzymatic or chemical fragmentation. These approaches make the sample more suitable for chromatographic and mass spectrometric analysis. Structural elucidation and quality control (QC) analysis of biopharmaceutics are usually performed at intact, subunit and peptide levels. In this paper, general sample preparation approaches used to attain peptide, subunit and glycan level analysis are overviewed. Protocols are described to perform tryptic proteolysis, IdeS and papain digestion, reduction as well as deglycosylation by PNGase F and EndoS2 enzymes. Both historical and modern sample preparation methods were compared and evaluated using rituximab and trastuzumab, two reference therapeutic mAb products approved by Food and Drug Administration (FDA) and European Medicines Agency (EMA). The described protocols may help analysts to develop sample preparation methods in the field of therapeutic protein analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Characteristics of Barium Hexaferrite Nanoparticles Prepared by Temperature-Controlled Chemical Coprecipitation

    International Nuclear Information System (INIS)

    Kwak, Jun Young; Lee, Choong Sub; Kim, Don; Kim, Yeong Il

    2012-01-01

    Ba-ferrite (BaFe 12 O 19 ) nanoparticles were synthesized by chemical coprecipitation method in an aqueous solution. The particle size and the crystallization temperature of the Ba-ferrite nanoparticles were controlled varying the precipitation temperature. The precipitate that was prepared at 0 .deg. C showed the crystal structure of Ba-ferrite in X-ray diffraction when it was calcined at the temperature above 580 .deg. C, whereas what was prepared at 50 .deg. C showed the crystallinity when it was calcined at the temperature higher than about 700 .deg. C. The particle sizes of the synthesized Ba-ferrite were in a range of about 20-30 nm when it was prepared by being precipitated at 0 .deg. C and calcined at 650 .deg. C. When the precipitation temperature increased, the particle size also increased even at the same calcination temperature. The magnetic properties of the Ba-ferrite nanoparticles were also controlled by the synthetic condition of precipitation and calcination temperature. The coercive force could be appreciably lowered without a loss of saturation magnetization when the Ba-ferrite nanoparticles were prepared by precipitation and calcination both at low temperatures

  3. Process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition

    Science.gov (United States)

    Lackey, Jr., Walter J.; Caputo, Anthony J.

    1986-01-01

    A chemical vapor deposition (CVD) process for preparing fiber-reinforced ceramic composites. A specially designed apparatus provides a steep thermal gradient across the thickness of a fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.

  4. Effect of borohydride addition rate on chemically prepared amorphous Fe-B particles

    International Nuclear Information System (INIS)

    Koch, C.B.; Morup, S.; Linderoth, S.

    1991-01-01

    Amorphous Fe-B alloys can be prepared by reacting aqueous solutions of Fe salts and NaBH 4 . In this paper the effect of the addition rate of the NaBH 4 solution to the FeSO 4 solution on the precipitate is investigated. The chemical composition of the amorphous alloys formed varies between Fe 79 B 21 and Fe 68 B 32 . The hyperfine parameters of the alloys, derived from Mossbauer spectra, show a decrease from 29 to 25 T of the magnetic hyperfine field and an increase from 0.19 to 0.28 mms -1 of the isomer shift with increasing NaBH 4 addition rate. The results suggest that alloys with different structures but identical composition may be produced by chemical reduction

  5. Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder

    OpenAIRE

    Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana

    2010-01-01

    Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin conten...

  6. Chemical separation of plutonium from air filters and preparation of filaments for resonance ionization mass spectroscopy

    International Nuclear Information System (INIS)

    Eberhardt, K.; Erdmann, N.; Funk, H.; Herrmann, G.; Naehler, A.; Passler, G.; Trautmann, N.; Urban, F.

    1995-01-01

    Resonance ionization mass spectroscopy (RIMS) is used for the determination of plutonium in environmental samples. A chemical procedure based on an ion-exchange technique for the separation of plutonium from a polycarbonate filter is described. The overall yield is about 60% as determined by α-particle spectroscopy. A technique for the subsequent preparation of samples for RIMS measurements is developed. Plutonium is electrode-posited as hydroxide and covered with a thin metallic layer. While heating such a sandwich filament the plutonium hydroxide is reduced to the metal and an atomic beam is evaporated from the surface, as required for RIMS. copyright American Institute of Physics 1995

  7. Preparation and Characterization of Chemical Plugs Based on Selected Hanford Waste Simulants

    International Nuclear Information System (INIS)

    Mattigod, Shas V.; Wellman, Dawn M.; Parker, Kent E.; Cordova, Elsa A.; Gunderson, Katie M.; Baum, Steven R.; Crum, Jarrod V.; Poloski, Adam P.

    2008-01-01

    This report presents the results of preparation and characterization of chemical plugs based on selected Hanford Site waste simulants. Included are the results of chemical plug bench testing conducted in support of the M1/M6 Flow Loop Chemical Plugging/Unplugging Test (TP-RPP-WTP-495 Rev A). These results support the proposed plug simulants for the chemical plugging/ unplugging tests. Based on the available simulant data, a set of simulants was identified that would likely result in chemical plugs. The three types of chemical plugs that were generated and tested in this task consisted of: 1. Aluminum hydroxide (NAH), 2. Sodium aluminosilicate (NAS), and 3. Sodium aluminum phosphate (NAP). While both solvents, namely 2 molar (2 M) nitric acid (HNO3) and 2 M sodium hydroxide (NaOH) at 60 C, used in these tests were effective in dissolving the chemical plugs, the 2 M nitric acid was significantly more effective in dissolving the NAH and NAS plugs. The caustic was only slightly more effecting at dissolving the NAP plug. In the bench-scale dissolution tests, hot (60 C) 2 M nitric acid was the most effective solvent in that it completely dissolved both NAH and NAS chemical plugs much faster (1.5 - 2 x) than 2 M sodium hydroxide. So unless there are operational benefits for the use of caustic verses nitric acid, 2 M nitric acid heated to 60 C should be the solvent of choice for dissolving these chemical plugs. Flow-loop testing was planned to identify a combination of parameters such as pressure, flush solution, composition, and temperature that would effectively dissolve and flush each type of chemical plug from preformed chemical plugs in 3-inch-diameter and 4-feet-long pipe sections. However, based on a review of the results of the bench-top tests and technical discussions, the Waste Treatment Plant (WTP) Research and Technology (R and T), Engineering and Mechanical Systems (EMS), and Operations concluded that flow-loop testing of the chemically plugged pipe sections

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

    International Nuclear Information System (INIS)

    Garcia, L.V.; Mendivil, M.I.; Garcia Guillen, G.; Aguilar Martinez, J.A.; Krishnan, B.; Avellaneda, D.; Castillo, G.A.; Das Roy, T.K.; Shaji, S.

    2015-01-01

    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

  9. 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.

  10. Characterization of Korean Red Ginseng (Panax ginseng Meyer: History, preparation method, and chemical composition

    Directory of Open Access Journals (Sweden)

    Sang Myung Lee

    2015-10-01

    Full Text Available It has been reported that Korean Red Ginseng has been manufactured for 1,123 y as described in the GoRyeoDoGyeong record. The Korean Red Ginseng manufactured by the traditional preparation method has its own chemical component characteristics. The ginsenoside content of the red ginseng is shown as Rg1: 3.3 mg/g, Re: 2.0 mg/g, Rb1: 5.8 mg/g, Rc:1.7 mg/g, Rb2: 2.3 mg/g, and Rd: 0.4 mg/g, respectively. It is known that Korean ginseng generally consists of the main root and the lateral or fine roots at a ratio of about 75:25. Therefore, the red ginseng extract is prepared by using this same ratio of the main root and lateral or fine roots and processed by the historical traditional medicine prescription. The red ginseng extract is prepared through a water extraction (90°C for 14–16 h and concentration process (until its final concentration is 70–73 Brix at 50–60°C. The ginsenoside contents of the red ginseng extract are shown as Rg1: 1.3 mg/g, Re: 1.3 mg/g, Rb1: 6.4 mg/g, Rc:2.5 mg/g, Rb2: 2.3 mg/g, and Rd: 0.9 mg/g, respectively. Arginine-fructose-glucose (AFG is a specific amino-sugar that can be produced by chemical reaction of the process when the fresh ginseng is converted to red ginseng. The content of AFG is 1.0–1.5% in red ginseng. Acidic polysaccharide, which has been known as an immune activator, is at levels of 4.5–7.5% in red ginseng. Therefore, we recommended that the chemical profiles of Korean Red Ginseng made through the defined traditional method should be well preserved and it has had its own chemical characteristics since its traditional development.

  11. Preparation and properties of the magnetic absorbent polymer via the chemical transformation process

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shengyu, E-mail: liusytyut@sina.com [Department of Mineral Processing, College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Key Laboratory of In-situ Property-improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Zhang, Suhong, E-mail: zhangsh04@sina.com [Department of Mineral Processing, College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Jianying; Wen, Jing; Qiao, Yan [Department of Mineral Processing, College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2017-01-15

    Magnetic polyacrylic acid sodium polymer (MPAAS) was prepared by chemical transformation method. Key parameters were investigated in the synthesis process of the magnetic polymer and an optimum preparation condition was gained. The structure of the magnetic polymer was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrosocopy (FTIR) and scanning electron microscope (SEM). Magnetic property of the magnetic polymer was measured by the magnet and superconducting quantum interference device (SQUID). Both the swelling ratio and kinetics and the water retention ratio and kinetics were investigated. Based on the results, it can be gained that both swelling rate and equilibrium swelling rate were lowered after magnetization while the water retention ability of the magnetic polymer is stronger than that of the polymer. - Highlights: • The preparation mechanism of the magnetic polymer was proposed. • The magnetic property of the magnetic polymer was related to reaction conditions. • Swelling ratio and kinetics of polymer and magnetic polymer were studied. • Water retention ratio and kinetics of polymer and magnetic polymer were studied.

  12. Preparation and properties of the magnetic absorbent polymer via the chemical transformation process

    International Nuclear Information System (INIS)

    Liu, Shengyu; Zhang, Suhong; Guo, Jianying; Wen, Jing; Qiao, Yan

    2017-01-01

    Magnetic polyacrylic acid sodium polymer (MPAAS) was prepared by chemical transformation method. Key parameters were investigated in the synthesis process of the magnetic polymer and an optimum preparation condition was gained. The structure of the magnetic polymer was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrosocopy (FTIR) and scanning electron microscope (SEM). Magnetic property of the magnetic polymer was measured by the magnet and superconducting quantum interference device (SQUID). Both the swelling ratio and kinetics and the water retention ratio and kinetics were investigated. Based on the results, it can be gained that both swelling rate and equilibrium swelling rate were lowered after magnetization while the water retention ability of the magnetic polymer is stronger than that of the polymer. - Highlights: • The preparation mechanism of the magnetic polymer was proposed. • The magnetic property of the magnetic polymer was related to reaction conditions. • Swelling ratio and kinetics of polymer and magnetic polymer were studied. • Water retention ratio and kinetics of polymer and magnetic polymer were studied.

  13. High quality antireflective ZnS thin films prepared by chemical bath deposition

    International Nuclear Information System (INIS)

    Tec-Yam, S.; Rojas, J.; Rejón, V.; Oliva, A.I.

    2012-01-01

    Zinc sulfide (ZnS) thin films for antireflective applications were deposited on glass substrates by chemical bath deposition (CBD). Chemical analysis of the soluble species permits to predict the optimal pH conditions to obtain high quality ZnS films. For the CBD, the ZnCl 2 , NH 4 NO 3 , and CS(NH 2 ) 2 were fixed components, whereas the KOH concentration was varied from 0.8 to 1.4 M. Groups of samples with deposition times from 60 to 120 min were prepared in a bath with magnetic agitation and heated at 90 °C. ZnS films obtained from optimal KOH concentrations of 0.9 M and 1.0 M exhibited high transparency, homogeneity, adherence, and crystalline. The ZnS films presented a band gap energy of 3.84 eV, an atomic Zn:S stoichiometry ratio of 49:51, a transmittance above 85% in the 300–800 nm wavelength range, and a reflectance below 25% in the UV–Vis range. X-ray diffraction analysis revealed a cubic structure in the (111) orientation for the films. The thickness of the films was tuned between 60 nm and 135 nm by controlling the deposition time and KOH concentration. The incorporation of the CBD-ZnS films into ITO/ZnS/CdS/CdTe and glass/Mo/ZnS heterostructures as antireflective layer confirms their high optical quality. -- Highlights: ► High quality ZnS thin films were prepared by chemical bath deposition (CBD). ► Better CBD-ZnS films were achieved by using 0.9 M-KOH concentration. ► Reduction in the reflectance was obtained for ZnS films used as buffer layers.

  14. A comparison of the microstructures and electrochemical capacitive properties of 2 graphenes prepared by arc discharge method and chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.; Yang, Y. [Research Inst. of Chemical Defense, Beijing (China); Univ. of Science and Technology, Beijing (China); Cao, G.; Xu, B. [Research Inst. of Chemical Defense, Beijing (China)

    2010-07-01

    In this study, 2 kinds of graphene materials were prepared using both arc discharge and chemical methods. The pore structures and electrochemical capacitive properties of the materials were investigated. A mesopore structure was obtained for the graphene prepared using the arc discharge method, with a capacitance of 12.9 F/g and a high rate capability when used in electrochemical applications. The graphene prepared with the chemical method demonstrated a more highly developed micropore structure and capacitances greater than 70 F/g. However, rate performance for the graphene was normal. 2 figs.

  15. Preparation and characterization of poly(acrylic acid)—corn starch blend for use as chemical sand-fixing materials

    Science.gov (United States)

    Dang, Xugang; Chen, Hui; Shan, Zhihua

    2017-07-01

    One chemical sand-fixing materials based on poly(acrylic acid)-corn starch (PACS) blend was studied in this work. The PACS blend was prepared by solution mixing method between PA and CS. In order to prepare sand-fixing materials for environmental applications using the well-established method of spraying evenly PACS blend solution on the surfaces of fine sand. Fourier transform infrared spectroscopy (FT-IR) revealed the existence of the intermolecular interactions between the blend components. Scanning electron microscope (SEM) analysis showed a continuous phase of blend, and it also showed the good sand-fixing capacity. The test results of hygroscopicity and water retention experiments indicated that the blends had excellent water-absorbing and water-retention capacity. The results of contact angle measurements between the PACS solutions and fine sand showed that the PACS blend has a satisfactory effect on fine sand wetting. And the PACS, as a sand-fixation material, has excellent sand-fixation rate up to 99.5%.

  16. Electrical properties of the n-ZnO/c-Si heterojunction prepared by chemical spray pyrolysis

    International Nuclear Information System (INIS)

    Romero, R.; Lopez, M.C.; Leinen, D.; Martin, F.; Ramos-Barrado, J.R.

    2004-01-01

    Electrical, structural and compositional properties of n-ZnO/c-Si heterojunctions prepared by chemical spray pyrolysis on single-crystal n-type and p-type monocrystalline silicon(1 0 0) substrates are examined with the C-V method and admittance spectroscopy at temperature ranges between 223 and 373 K. The n-ZnO/c-Si heterojunctions show a height barrier consistent with the difference in energy of the work functions of Si and ZnO; however, the n-ZnO:Al/c-Si heterojunctions present a more complex behavior due to the defects at or near the n-ZnO:Al/c-Si interface, causing a Fermi energy pinning

  17. Zinc Sulfide Buffer Layer for CIGS Solar Cells Prepared by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Rui-Wei You

    2016-11-01

    Full Text Available In this study, ZnS thin films were successfully synthesized by chemical bath deposition (CBD with starting materials of NH2-NH2, SC(NH22, and ZnSO4‧7H2O. ZnS thin films were deposited with different time on glass substrates by CBD at 80oC and pH=9. Based on X-ray diffraction (XRD patterns, it is found that the ZnS thin films exhibit cubic polycrystalline phase. It was found that the optimum deposition time is 90 min for preparing ZnS thin film that is suitable as buffer layer for CuIn1-xGaxSe2 solar cells. The thin film deposited for 90 min has high transmittance up to 80% in the spectra range from 350 nm to 800 nm, and the optical band gap is about 3.59 eV.

  18. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    Rahman, M.M.; Khan, S.B.; Asiri, A.M.; Jamal, A.; Faisal, M.

    2012-01-01

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r 2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm -2 mM -1 , and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  19. Preparation of functional composite materials based on chemically derived graphene using solution process

    International Nuclear Information System (INIS)

    Kim, M; Hyun, W J; Mun, S C; Park, O O

    2015-01-01

    Chemically derived graphenes were assembled into functional composite materials using solution process from stable solvent dispersion. We have developed foldable electronic circuits on paper substrates using vacuum filtration of graphene nanoplates dispersion and a selective transfer process without need for special equipment. The electronic circuits on paper substrates revealed only a small change in conductance under various folding angles and maintained an electronic path after repetitive folding and unfolding. We also prepared flexible. binder-free graphene paper-like materials by addition of graphene oxide as a film stabilizer. This graphene papers showed outstanding electrical conductivity up to 26,000 S/m and high charge capacity as an anode in lithium-ion battery without any post-treatments. For last case, multi-functional thin film structures of graphene nanoplates were fabricated by using layer-by-layer assembly technique, showing optical transparency, electrical conductivity and enhanced gas barrier property. (paper)

  20. Preparation of nanocrystalline ZnS by a new chemical bath deposition route

    Energy Technology Data Exchange (ETDEWEB)

    Sartale, S.D. [Department of Heterogeneous Material Systems (SE2), Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Sankapal, B.R. [Department of Heterogeneous Material Systems (SE2), Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Lux-Steiner, M. [Department of Heterogeneous Material Systems (SE2), Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Ennaoui, A. [Department of Heterogeneous Material Systems (SE2), Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany)]. E-mail: ennaoui@hmi.de

    2005-06-01

    We report a new chemical bath deposition route for the preparation of dense, compact and uniform nanocrystalline ZnS thin films, where thiourea acts as a complexing agent as well as a source of sulfide ions. The structural and morphological characterizations suggest that the film and the residual powder in the bath are formed by the aggregation of clusters of ZnS, namely cluster-by-cluster growth mechanism. X-ray diffraction (XRD) and HRTEM analyses indicate that the film and powder formed in the bath have cubic zinkblende structure. The films have high transmittance of about 75% in the visible region. Post-deposition annealing in Ar slightly improves the crystallinity and decreases the optical bandgap with increasing the annealing temperature.

  1. Preparation of nanocrystalline ZnS by a new chemical bath deposition route

    International Nuclear Information System (INIS)

    Sartale, S.D.; Sankapal, B.R.; Lux-Steiner, M.; Ennaoui, A.

    2005-01-01

    We report a new chemical bath deposition route for the preparation of dense, compact and uniform nanocrystalline ZnS thin films, where thiourea acts as a complexing agent as well as a source of sulfide ions. The structural and morphological characterizations suggest that the film and the residual powder in the bath are formed by the aggregation of clusters of ZnS, namely cluster-by-cluster growth mechanism. X-ray diffraction (XRD) and HRTEM analyses indicate that the film and powder formed in the bath have cubic zinkblende structure. The films have high transmittance of about 75% in the visible region. Post-deposition annealing in Ar slightly improves the crystallinity and decreases the optical bandgap with increasing the annealing temperature

  2. Synthesis and spectroscopic characterization of gold nanobipyramids prepared by a chemical reduction method

    International Nuclear Information System (INIS)

    Ngo, Vo Ke Thanh; Huynh, Trong Phat; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Lam, Quang Vinh; Huynh, Thanh Dat

    2015-01-01

    Gold nanobipyramids (NBPs) have attracted much attention because they have potential for applications in smart sensing devices, such as medical diagnostic equippments. This is due to the fact that they show more advantageous plasmonic properties than other gold nanostructures. We describe a chemical reduction method for synthesizing NBPs using conventional heating with ascorbic acid reduction and cetyltrimethylamonium bromide (CTAB) + AgNO_3 as capping agents. The product was characterized by ultraviolet–visible spectroscopy (UV–vis), Fourier transmission infrared spectroscopy (FTIR), transmission electron microscopy (TEM), x-ray powder diffraction (XRD). The results showed that gold nanoparticles were formed with bipyramid shape (tip-to-tip distance of 88.4 ± 9.4 nm and base length of 29.9 ± 3.2 nm) and face-centered-cubic crystalline structure. Optimum parameters for preparation of NBPs are also found. (paper)

  3. Synthesis and spectroscopic characterization of gold nanobipyramids prepared by a chemical reduction method

    Science.gov (United States)

    Thanh Ngo, Vo Ke; Phat Huynh, Trong; Giang Nguyen, Dang; Phuong Uyen Nguyen, Hoang; Lam, Quang Vinh; Dat Huynh, Thanh

    2015-12-01

    Gold nanobipyramids (NBPs) have attracted much attention because they have potential for applications in smart sensing devices, such as medical diagnostic equippments. This is due to the fact that they show more advantageous plasmonic properties than other gold nanostructures. We describe a chemical reduction method for synthesizing NBPs using conventional heating with ascorbic acid reduction and cetyltrimethylamonium bromide (CTAB) + AgNO3 as capping agents. The product was characterized by ultraviolet-visible spectroscopy (UV-vis), Fourier transmission infrared spectroscopy (FTIR), transmission electron microscopy (TEM), x-ray powder diffraction (XRD). The results showed that gold nanoparticles were formed with bipyramid shape (tip-to-tip distance of 88.4 ± 9.4 nm and base length of 29.9 ± 3.2 nm) and face-centered-cubic crystalline structure. Optimum parameters for preparation of NBPs are also found.

  4. Fabrication and Characterization of Zinc Sulfide Nanoparticles and Nanocomposites Prepared via a Simple Chemical Precipitation Method

    Directory of Open Access Journals (Sweden)

    Kambiz Hedayati

    2016-07-01

    Full Text Available In this research zinc sulfide (ZnS nanoparticles and nanocomposites powders were prepared by chemical precipitation method using zinc acetate and various sulfur sources. The ZnS nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible and fourier transform infra-red. The structure of nanoparticles was studied using X-ray diffraction pattern. The crystallite size of ZnS nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the scanning electron microscopy. The grain size of zinc sulfide nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. The optical properties of particles were studied with ultraviolet-visible absorption spectrum.

  5. Effect of Organic Solvents in Preparation of Silica-Based Chemical Gel Decontaminates for Decontamination of Nuclear Facilities

    International Nuclear Information System (INIS)

    Yoon, Suk Bon; Jung, Chong Hun; Kim, Chang Ki; Choi, Byung Seon; Lee, Kune Woo; Moon, Jei Kwon

    2011-01-01

    Decontamination of nuclear facilities is necessary to reduce the radiation field during normal operations and decommissioning of complex equipment such as stainless steel components, other iron-based steel and alloys, metal surfaces, structural materials and so on. Chemical decontamination technology in particular is a highly effective method to remove the radioactive contamination through a chemical dissolution or a redox reaction. However, this method has the serious drawback due to the generation of large amounts of the radioactive liquid wastes. Recently, a few literatures have been reported for the preparation of the chemical gel decontaminants to reduce the amount of the radioactive liquid wastes and to enhance the decontamination efficiency through increasing the contact time between the gels and the radioactive contaminants. In the preparation of the chemical gels, the control of the viscosity highly depends on the amount of a coviscosifier used among the components of the chemical gels consisted of a viscosifier, a coviscosifier, and a chemical decontaminant. In this works, a new effective method for the preparation of the chemical gel was investigated by introducing the organic solvents. The mixture solution of the coviscosifier and organic solvent was more effective in the control of the viscosity compared with that of the coviscosifier only in gels. Furthermore, the decontamination efficiency of the chemical gels measured by using the multi-channel analyzer (MCA) showed the high decontamination factor for Co-60 and Cs-137 contaminated on the surface of the stainless steel 304

  6. Occurrence of two-photon absorption saturation in Ag nanocolloids, prepared by chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Rahulan, K. Mani, E-mail: krahul.au@gmail.com [Department of Physics, Anna University, Chennai (India); Ganesan, S. [Department of Physics, Anna University, Chennai (India); Aruna, P., E-mail: aruna@annauniv.edu [Department of Physics, Anna University, Chennai (India)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Ag nanocolloids were synthesized via chemical reduction method. Black-Right-Pointing-Pointer The molecules of PVP play an important role in growth and agglomeration of silver nanocolloids. Black-Right-Pointing-Pointer Saturation behaviour followed by two photon absorption was responsible for good optical limiting characteristics in these nanocolloids. Black-Right-Pointing-Pointer The nonlinear optical parameters calculated from the data showed that these materials could be used as efficient optical limiters. - Abstract: Silver nanocolloids stabilized with polyvinyl pyrrolidone (PVP) have been prepared from (AgNO{sub 3}) by a chemical reduction method, involving the intermediate preparation of (Ag{sub 2}O) colloidal dispersions in the presence of sodium dodecycle sulfate as a surfactant and formaldehyde as reducing agent. The molecules of PVP play an important role in growth and agglomeration of silver nanocolloids. The formation of Ag nanocolloids was studied from the UV-vis absorption characteristics. An energy dispersive X-ray (EDX) spectrum and X-ray diffraction peak of the nanoparticles showed the highly crystalline nature of silver structure. The particle size was found to be 40 nm as analyzed from Field emission scanning electron microscopy (FESEM). The nonlinear optical and optical limiting properties of these nanoparticle dispersions were studied by using the Z-scan technique at 532 nm. Experimental results show that the Ag nanocolloids possess strong optical limiting effect, originated from absorption saturation followed by two-photon mechanism. The data show that Ag nanocolloids have great potential for nonlinear optical devices.

  7. Morphology of CdSe films prepared by chemical bath deposition: The role of substrate

    International Nuclear Information System (INIS)

    Simurda, M.; Nemec, P.; Formanek, P.; Nemec, I.; Nemcova, Y.; Maly, P.

    2006-01-01

    We combine optical spectroscopy and transmission electron microscopy to study the growth and the structural morphology of CdSe films prepared by chemical bath deposition (CBD) on two considerably different substrates. The films grown on glass are compact and strongly adherent to the substrate. On the contrary, the films deposited on carbon-coated glass (with approx. 20 nm thick amorphous carbon layer) are only loosely adherent to the substrate. Using transmission electron microscopy we revealed that even though the films grown on both substrates are assembled from closely spaced nanocrystals with diameter of about 5 nm, the films morphology on the sub-micrometer scale is considerably different in the two cases. While the films deposited on glass are rather compact, the films prepared on carbon layer have high porosity and are formed by interconnected spheres which size is dependent on the duration of deposition (e.g. 155 nm for 6 h and 350 nm for 24 h). This shows that the choice of the substrate for CBD has a stronger influence on the sub-micrometer film morphology than on the properties of individual nanocrystals forming the film

  8. Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhen [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Zhang Zhonghua [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)], E-mail: zh_zhang@sdu.edu.cn; Jia Haoling [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Qu Yingjie [Shandong Labor Occupational Technology College, Jingshi Road 388, Jinan 250022 (China); Liu Guodong; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)

    2009-03-20

    In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N{sub 2} adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at.% Ni alloy consists of {alpha}-Al, NiAl{sub 3} and Ni{sub 2}Al{sub 3}, while the melt spun Al-25 and 31.5 at.% Ni alloys comprise NiAl{sub 3} and Ni{sub 2}Al{sub 3}. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.

  9. Preparation of Ti species coating hydrotalcite by chemical vapor deposition for photodegradation of azo dye.

    Science.gov (United States)

    Xiao, Gaofei; Zeng, HongYan; Xu, Sheng; Chen, ChaoRong; Zhao, Quan; Liu, XiaoJun

    2017-10-01

    TiO 2 in anatase crystal phase is a very effective catalyst in the photocatalytic oxidation of organic compounds in water. To improve its photocatalytic activity, the Ti-coating MgAl hydrotalcite (Ti-MgAl-LDH) was prepared by chemical vapor deposition (CVD) method. Response surface method (RSM) was employed to evaluate the effect of Ti species coating parameters on the photocatalytic activity, which was found to be affected by the furnace temperature, N 2 flow rate and influx time of precursor gas. Application of RSM successfully increased the photocatalytic efficiency of the Ti-MgAl-LDH in methylene blue photodegradation under UV irradiation, leading to improved economy of the process. According to the results from X-ray diffraction, scanning electron microscopy, Brunner-Emmet-Teller and Barrett-Joyner-Hallender, thermogravimetric and differential thermal analysis, UV-vis diffuse reflectance spectra analyses, the Ti species (TiO 2 or/and Ti 4+ ) were successfully coated on the MgAl-LDH matrix. The Ti species on the surface of the Ti-MgAl-LDH lead to a higher photocatalytic performance than commercial TiO 2 -P25. The results suggested that CVD method provided a new approach for the industrial preparation of Ti-coating MgAl-LDH material with good photocatalytic performances. Copyright © 2017. Published by Elsevier B.V.

  10. Preparation of Al2O3/Mo nanocomposite powder via chemical route and spray drying

    International Nuclear Information System (INIS)

    Lo, M.; Cheng, F.; Wei, W.J.

    1996-01-01

    A route to prepare nanometer-sized Mo particulates in Al 2 O 3 was attempted by a combination of solution reactions in molecular scale and forcing precipitation by a spray-drying technique. MoO 3 was first dissolved in ammonia water and then added in the slurry with high purity, submicrometer Al 2 O 3 powder. Mixed suspension was spray-dried, and then the dried granules were reduced by hydrogen gas and further hot-pressing to a bulky composite at various temperatures. Dissolution of Mo oxide, adsorption reactions on alumina surface, and surface potential of alumina particles in homogeneous ammonia suspension were studied. Characterization of the granules, including compactability, flowing properties, surface morphology, grain growth of Mo and Al 2 O 3 , and mixing homogeneity, were examined. Homogeneity of the spray-dried granules was determined by the calculation of mixing index and the observation of the microstructure of sintered body. The existence of intergranular, intragranular, and nanosized Mo particulates within Al 2 O 3 grains was observed by transmission electron microscopy (TEM). All the evidences revealed that homogeneous composites with nanometer-sized Mo had been successfully prepared by this attempt with the proposed chemical route and following spray-drying process. copyright 1996 Materials Research Society

  11. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    International Nuclear Information System (INIS)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi_3Fe_5O_1_2, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches −5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods. - Highlights: • Thin film of polycrystalline Bi_3Fe_5O_1_2 was prepared by the mist CVD method. • Optimized conditions were found for the synthesis of single phase of Bi_3Fe_5O_1_2. • The Faraday rotation angle at 633 nm is –5.2 deg/μm at room temperature. • The Faraday rotation is interpreted by the electronic transitions of Fe"3"+ ions.

  12. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa, E-mail: tanaka@dipole7.kuic.kyoto-u.ac.jp

    2017-01-15

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi{sub 3}Fe{sub 5}O{sub 12}, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches −5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods. - Highlights: • Thin film of polycrystalline Bi{sub 3}Fe{sub 5}O{sub 12} was prepared by the mist CVD method. • Optimized conditions were found for the synthesis of single phase of Bi{sub 3}Fe{sub 5}O{sub 12}. • The Faraday rotation angle at 633 nm is –5.2 deg/μm at room temperature. • The Faraday rotation is interpreted by the electronic transitions of Fe{sup 3+} ions.

  13. Characterization of mesoporous carbon prepared from date stems by H3PO4 chemical activation

    International Nuclear Information System (INIS)

    Hadoun, H.; Sadaoui, Z.; Souami, N.; Sahel, D.; Toumert, I.

    2013-01-01

    The present work was focused on the determination of texture, morphology, crystanillity and oxygenated surface groups characteristics of an activated carbon prepared from date stems. Chemical activation of this precursor at different temperatures (450, 550 and 650 °C) was adopted using phosphoric acid as dehydrating agent at (2/1) impregnation ratio. Fourier transform infrared spectroscopy study was carried out to identify surface groups in date stems activated carbons. The microscopic structure was examined by nitrogen adsorption at 77 K. The interlayer spacing (d 200 and d 100 ), stack height (L c ), stack width (L a ) and effective dimension L of the turbostratic crystallites (microcrystallite) in the date stems activated carbons were estimated from X-ray diffraction data (XRD). Results yielded a surface area, S BET , and total pore volume of 682, 1455, 1319 m 2 /g and 0,343, 1,045 and 0.735 cm 3 /g, for the carbon prepared at 450, 550 and 650 °C, respectively. Scanning electron microscopy exhibits a highly developed porosity which is in good agreement with the porous texture derived from gas adsorption data and these results confirm that the activated carbon is dominated by network of slit-shaped mesopores morphology and in some cases by varied micropores morphologies.

  14. Structure and composition of chemically prepared and vacuum annealed InSb(0 0 1) surfaces

    International Nuclear Information System (INIS)

    Tereshchenko, O.E.

    2006-01-01

    The InSb(0 0 1) surfaces chemically treated in HCl-isopropanol solution and annealed in vacuum were studied by means of X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and electron energy-loss spectroscopy (EELS). The HCl-isopropanol treatment removes indium and antimony oxides and leaves on the surface about 3 ML of physisorbed overlayer, containing indium chlorides and small amounts of antimony, which can be thermally desorbed at 230 deg. C. The residual carbon contaminations were around 0.2-0.4 ML and consisted of the hydrocarbon molecules. These hydrocarbon contaminations were removed from the surface together with the indium chlorides and antimony overlayer. With increased annealing temperature, a sequence of reconstructions were identified by LEED: (1 x 1), (1 x 3), (4 x 3), and (4 x 1)/c(8 x 2), in the order of decreasing Sb/In ratio. The structural properties of chemically prepared InSb(0 0 1) surface were found to be similar to those obtained by decapping of Sb-capped epitaxial layers

  15. FragIt: a tool to prepare input files for fragment based quantum chemical calculations.

    Directory of Open Access Journals (Sweden)

    Casper Steinmann

    Full Text Available Near linear scaling fragment based quantum chemical calculations are becoming increasingly popular for treating large systems with high accuracy and is an active field of research. However, it remains difficult to set up these calculations without expert knowledge. To facilitate the use of such methods, software tools need to be available to support these methods and help to set up reasonable input files which will lower the barrier of entry for usage by non-experts. Previous tools relies on specific annotations in structure files for automatic and successful fragmentation such as residues in PDB files. We present a general fragmentation methodology and accompanying tools called FragIt to help setup these calculations. FragIt uses the SMARTS language to locate chemically appropriate fragments in large structures and is applicable to fragmentation of any molecular system given suitable SMARTS patterns. We present SMARTS patterns of fragmentation for proteins, DNA and polysaccharides, specifically for D-galactopyranose for use in cyclodextrins. FragIt is used to prepare input files for the Fragment Molecular Orbital method in the GAMESS program package, but can be extended to other computational methods easily.

  16. Comparison of Three Sample Preparation Methods for Analysis of Chemical Warfare Agent Stimulants in Water

    International Nuclear Information System (INIS)

    Alessandro Sassolini

    2015-01-01

    Analytical chemistry in CBRNe (Chemical Biological Radiological Nuclear explosive) context requires not only high quality data; quickness, ruggedness and robustness are also mandatory. In this work, three samples preparation methods were compared using several organophosphorus pesticides as test compounds, used as stimulants of nerve CWA (Chemical Warfare Agents) to choose the one with best characteristics. Result was obtained better with the Dispersive Liquid-Liquid Micro Extraction (DLLME), relatively new in CBRNe field, obtaining uncertainty for different simulants between 8 and 15 % while a quantification limit between 0.01 and 0.08 μg/ l. To optimize this extraction method, different organo chlorinated solvents also tested but not relevant difference in these tests was obtained. In this work, all samples were analyzed by using a gas chromatography coupled with mass spectrometer (GC-MS) and also with Gas Chromatograph coupled with Nitrogen Phosphorous Detector (NPD) for DLLME samples to evaluate a low cost and rugged instrument adapt to field analytical methods with good performance in terms of uncertainty and sensibility even if poorer respect to the mass spectrometry. (author)

  17. Preparation and chemical stability of iron-nitride-coated iron microparticles

    International Nuclear Information System (INIS)

    Luo Xin; Liu Shixiong

    2007-01-01

    Iron-nitride-coated iron microparticles were prepared by nitridation of the surface of iron microparticles with ammonia gas at a temperature of 510 deg. C. The phases, composition, morphology, magnetic properties, and chemical stability of the particles were studied. The phases were α-Fe, ε-Fe 3 N, and γ-Fe 4 N. The composition varied from the core to the surface, with 99.8 wt% Fe in the core, and 93.8 wt% Fe and 6 wt% N in the iron-nitride coating. The thickness of the iron-nitride coating was about 0.28 μm. The chemical stability of the microparticles was greatly improved, especially the corrosion resistance in corrosive aqueous media. The saturation magnetization and the coercive force were 17.1x10 3 and 68 kA/m, respectively. It can be concluded that iron-nitride-coated iron microparticles will be very useful in many fields, such as water-based magnetorheological fluids and polishing fluids

  18. Preparation of micro/nano-fibrous brushite coating on titanium via chemical conversion for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bing [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China); Guo, Yong-yuan [Orthopedic Department, Qilu Hospital of Shandong University, Ji’nan, 250012 (China); Xiao, Gui-yong [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China); Lu, Yu-peng, E-mail: biosdu@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China)

    2017-03-31

    Highlights: • A chemical conversion brushite coating was prepared on titanium. • The coating exhibits fibrous morphology in micro/nano-scale. • The surface of the coating shows high hydrophilicity and corrosion resistance in the simulated body fluid. • An improvement of cell response was observed on the surface of coated Ti compared to that of the uncoated. - Abstract: Calcium phosphate coatings have been applied on the surface of Ti implants to realize better osseointegration. The formation of dicalcium phosphate dihydrate (CaHPO{sub 4}·2H{sub 2}O), mineralogically named brushite on pure Ti substrate has been investigated via chemical conversion method. Coating composition and microstructure have been investigated by X-ray diffractometer, Fourier transform infrared spectrometer and field emission scanning electron microscope. The results reveal that the coatings are composed of high crystalline brushite with minor scholzite (CaZn{sub 2}(PO{sub 4}){sub 2}·2H{sub 2}O). A micro/nano-scaled fibrous morphology can be produced in the acidic chemical conversion bath with pH 5.00. The surface of the fibrous brushite coating exhibits high hydrophilicity and corrosion resistance in the simulated body fluid. The osteoblast cells grow and spread actively on the coated samples and the proliferation numbers and alkaline phosphate activities of the cells improve significantly compared to the uncoated Ti. It is suggested that the micro/nano-fibrous brushite coating can be a potential approach to improve the osteoinductivity and osteoconductivity of Ti implant, due to its similarity in morphology and dimension to inorganic components of biological hard tissues, and favorable responses to the osteoblasts.

  19. Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation.

    Science.gov (United States)

    Altenor, Sandro; Carene, Betty; Emmanuel, Evens; Lambert, Jacques; Ehrhardt, Jean-Jacques; Gaspard, Sarra

    2009-06-15

    Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X(P) (gH(3)PO(4)/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m(2)/g) and high pore volume (up to 1.19 cm(3)/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R(2)) and the normalized standard deviation Deltaq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB

  20. Preparation and Determination of the Physical and Chemical Properties of Margarine

    Directory of Open Access Journals (Sweden)

    Habazin, S.

    2012-02-01

    Full Text Available Nutrition is one of the most basic needs of the human body. It ensures the introduction of substances needed to sustain life of the organism, its growth and proper development. In the food pyramid, fats together with carbohydrates are at the very top. One source of fat in human nutrition is margarine. Margarine comprises at least 82 % vegetable fats and 16 % water. The remainder consists of lecithin, sugar, salt, colours, and vitamins.The margarine production process involves hydrogenation of vegetable fats, assembling the margarine mixture, emulsifying, crystallization and packing.The objective of this study was to show that margarine could be prepared in a school laboratory under conditions that are applicable for such laboratory. Meaning:a In a school laboratory at normal pressure and at elevated temperature with nickel as catalyst, i.e. without the use of an autoclave, carry out the reaction of hydrogenation soybean and palm oil in order to obtain a vegetable fat that is the basic ingredient of margarine. During the preparation of margarine, the hydrogenation reaction was carefully monitored by determining the iodine value.b Preparation of margarine obtained from vegetable fats.c Determination and comparison of selected physical and chemical properties of the product with the same properties of several types of margarines available on the market. The following properties were determined:– Melting point, in order to obtain composition of fat phase and determine suitability for humanuse.– Acid value, as an indicator of the amount of free fatty acids that influence the taste.– Peroxide value, for insight into the oxidative stability of fats.This work has shown that it is possible to make vegetable fat in a school lab by hydrogenation of vegetable oils. Unlike the industrial process of hydrogenation carried out under a pressure of 0.36 to 2 atm, which takes about two hours, our reaction was carried out at atmospheric pressure but with a

  1. The wetting of cladding materials and other metals and alloys by sodium

    International Nuclear Information System (INIS)

    Hodkin, E.N.; Nicholas, M.G.

    1976-05-01

    The sessile drop technique has been used to investigate the wetting behaviour between sodium and various metals and alloys including FV548, 316L, M316 and PE16. Unoxidised smooth surfaces of these alloys were not wetted by sodium containing 20 ppm of oxygen at temperatures below 300 0 C but were well wetted with advancing contact angles of 20 0 or less at temperatures of 550 0 to 600 0 C. Cold working and surface roughness had little effect on wetting behaviour but other factors exercised significant influences. Chemically or electrolytically polished M316 and PE16 surfaces were less readily wetted than those which had been prepared by mechanical polishing. In general, preoxidation of the alloy surfaces and increased oxygen contamination of the sodium had detrimental effects on wetting behaviour. On the other hand, increasing the chromium content of the alloys, decreasing the oxygen content of the sodium or ion bombarding the alloy sample surfaces had beneficial effects. Auger spectroscopy studies revealed a correlation between the chromium/oxygen ratio of PE16 surfaces and their wettability. The implications of this and other factors on fast reactor coolant/clad wetting behaviour is discussed. (author)

  2. Preparation of industrial chemicals by acid leaching from the koga nepheline syenite, southern Swat, lesser Himalayas-Pakistan

    International Nuclear Information System (INIS)

    Nizami, A.R.

    2012-01-01

    This paper encompasses the study on the preparation of industrial chemicals by acid leaching from the Koga nepheline syenite, Southern Swat, Lesser Himalayas-Pakistan. These rocks have been studied in detail by many workers to exploit their industrial utility in the form of powdered rock material in glass and ceramics and steel industry. The present authors for the first time carried out acid leaching studies and prepared a number of industrial chemicals, like, alumina, aluminium sulphate, sodium and ammonium alums, sodium sulphate) and sodium bisulphate by simple chemical reactions at bench scale successfully. The developed process is simple and economically viable. It is recommended to exploit this process in cottage industry in the mountainous areas hosting these rocks for the benefit of local population. The research and development work for production of these chemicals at pilot plant and industrial scale is recommended as well. (author)

  3. Evaluating the residual stress in PbTiO3 thin films prepared by a polymeric chemical method

    International Nuclear Information System (INIS)

    Valim, D; Filho, A G Souza; Freire, P T C; Filho, J Mendes; Guarany, C A; Reis, R N; Araujo, E B

    2004-01-01

    We report a study of residual stress in PbTiO 3 (PT) thin films prepared on Si substrates by a polymeric chemical method. The E(1TO) frequency was used to evaluate the residual stress through an empirical equation available for bulk PT. We find that the residual stress in PT films increases as the film thickness decreases and conclude that it originates essentially from the contributions of extrinsic and intrinsic factors. Polarized Raman experiments showed that the PT films prepared by a polymeric chemical method are somewhat a-domain (polar axis c parallel to the substrate) oriented

  4. Identification of chemicals relevant to the Chemical Weapons Convention using the novel sample-preparation methods and strategies of the Mobile Laboratory of the Organization for the Prohibition of Chemical Weapons

    NARCIS (Netherlands)

    Terzic, O.; Gregg, H.; de Voogt, P.

    2015-01-01

    The standard approach to on-site sample preparation for gas chromatography-mass spectrometry analysis of chemicals relevant to the Chemical Weapons Convention provides relatively good coverage of the target analytes, but it suffers from a number of drawbacks, such as low sample throughput, use of

  5. 1,5-Anhydro-D-fructose: biocatalytic and chemical synthetic methods for the preparation, transformation and derivatization

    DEFF Research Database (Denmark)

    Lundt, Inge; Yu, Shukun

    2010-01-01

    1,5-Anhydro-D-fructose (1,5AnFru) is a monoketosaccharide that can be prepared enzymatically from starch by a-1,4-glucan lyase or chemically from D-glucose or D-fructose in a few steps with high yields. The formed 1,5AnFru can be derivatized both enzymatically and chemically to interesting new...

  6. Preparation of K-doped TiO{sub 2} nanostructures by wet corrosion and their sunlight-driven photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Eunhye; Jin, Saera; Kim, Jiyoon; Chang, Sung-Jin [Department of Chemistry, Chung-Ang University, Seoul 06974 (Korea, Republic of); Jun, Byung-Hyuk [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Park, Kwang-Won, E-mail: bryan.kwangwon.park@gmail.com [Department of Chemistry, Chung-Ang University, Seoul 06974 (Korea, Republic of); Hong, Jongin, E-mail: hongj@cau.ac.kr [Department of Chemistry, Chung-Ang University, Seoul 06974 (Korea, Republic of)

    2016-08-30

    Highlights: • Potassium-doped TiO{sub 2} nanowire networks were prepared by the corrosion reaction of Ti nanoparticles in an alkaline solution. • They were applied to sunlight-driven photocatalytic degradation of differently charged dye molecules. • The adsorption of the dye molecules on the photocatalyst surface is crucial for their sunlight-driven photodegradation. - Abstract: K-doped TiO{sub 2} nanowire networks were prepared by the corrosion reaction of Ti nanoparticles in an alkaline (potassium hydroxide: KOH) solution. The prepared nanostructures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD) and photoluminescence (PL) spectra. Their sunlight-driven photocatalytic activity was also investigated with differently charged dye molecules, such as methylene blue, rhodamine B and methyl orange. The adsorption of the dye molecules on the photocatalyst surface would play a critical role in their selective photodegradation under sunlight illumination.

  7. Stabilization study on a wet-granule tableting method for a compression-sensitive benzodiazepine receptor agonist.

    Science.gov (United States)

    Fujita, Megumi; Himi, Satoshi; Iwata, Motokazu

    2010-03-01

    SX-3228, 6-benzyl-3-(5-methoxy-1,3,4-oxadiazol-2-yl)-5,6,7,8-tetrahydro-1,6-naphthyridin-2(1H)-one, is a newly-synthesized benzodiazepine receptor agonist intended to be developed as a tablet preparation. This compound, however, becomes chemically unstable due to decreased crystallinity when it undergoes mechanical treatments such as grinding and compression. A wet-granule tableting method, where wet granules are compressed before being dried, was therefore investigated as it has the advantage of producing tablets of sufficient hardness at quite low compression pressures. The results of the stability testing showed that the drug substance was chemically considerably more stable in wet-granule compression tablets compared to conventional tablets. Furthermore, the drug substance was found to be relatively chemically stable in wet-granule compression tablets even when high compression pressure was used and the effect of this pressure was small. After investigating the reason for this excellent stability, it became evident that near-isotropic pressure was exerted on the crystals of the drug substance because almost all the empty spaces in the tablets were occupied with water during the wet-granule compression process. Decreases in crystallinity of the drug substance were thus small, making the drug substance chemically stable in the wet-granule compression tablets. We believe that this novel approach could be useful for many other compounds that are destabilized by mechanical treatments.

  8. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  9. YBa2Cu3O7-x thin films prepared by chemical solution deposition

    International Nuclear Information System (INIS)

    Apetrii, Claudia

    2009-01-01

    The discovery of superconductivity in ceramic materials by Bednorz and Mueller in early 1987, immediately followed by Wu et al., who showed that YBa 2 Cu 3 O 7-x (YBCO) becomes superconducting (92 K) well above the boiling point of nitrogen (77 K) created a great excitement in superconductivity research. Potential applications of high T c -superconductors require large critical currents and high-applied magnetic fields. Effective ways to increase the critical current density at high magnetic fields in YBCO are the introduction of nanoparticles and chemical substitution of yttrium by other rare earth elements. Since low costs and environmental compatibility are essential conditions for the preparation of long length YBCO films, the cost effective chemical solution deposition (CSD) procedure was selected, given that no vacuum technology is required. To reveal the flexibility and the good optimization possibilities of the CSD approach two main processes were chosen for comparison: a fluorine-free method, namely the polymer-metal precursor technique, and a fluorine-based method, the metalorganic deposition (MOD) using the trifluoroacetates (TFA) technique. Sharp transition temperature widths ΔT c of 1.1 K for the polymer metal method, 0.8 K for TFA method and critical current densities J c of ∼3.5 MA/cm 2 shows that high quality YBCO thin films can be produced using both techniques. Especially interesting is the magnetic field dependence of the critical current density J c (B) of the Y(Dy)BCO (80 %) films showing that for the lower magnetic fields the critical current density J c (B) is higher for a standard YBCO film, but at fields higher than 4.5 T the critical current density J c (B) of Y(Dy)BCO is larger than that for the YBCO. Above 8 T, J c (B) of the Y(Dy)BCO film is more than one order of magnitude higher than in pure YBCO film. (orig.)

  10. Effect of gamma irradiation on microbial load, chemical and sensory properties of locally prepared fast meal

    International Nuclear Information System (INIS)

    Al-Bachir, M.

    2006-12-01

    Locally prepared meal (Kubba, Borak, Cheese borak and Sheesh Tawoq) was treated with 0, 2, 4, or 6 kGy doses of gamma irradiation. treated and untreated samples were kept in a refrigerators (1- 4 centigrade degree). Microbiological and chemical analyses were performed on each treated sample immediately after processing, and weekly throughout storage period which lasted for 3 weeks for Kubba, 6 weeks for Borak and Cheese Borak and 20 weeks for Sheesh Tawoq. Sensory evaluation and proximate analysis were done within one week after irradiation. Results of the proximate analysis of Borak, Cheese Borak and Sheesh Tawoq showed that irradiation doses did not have a significant effect on moisture, protein and fat content of meals. Whereas, irradiation decreased the major constituents of Kubba moisture, protein and fats. Used doses of gamma irradiation decreased the microorganisms load and increased the shelf-life of Kubba, Borak, Cheese Borak and Sheesh Tawoq. The radiation doses required to reduce the microorganisms load one log cycle (D 1 0) in Borak were 456 and 510 Gy and in cheese Borak 303 and 500 Gy for the Salmonella and E. coli respectively. The three chemical parameters, total acidity, lipid peroxide and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 3 weeks for Kubba, 6 weeks for Borak and Cheese Borak and 20 weeks for Sheesh Tawoq treated with 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  11. The chemical and catalytic properties of nanocrystalline metal oxides prepared through modified sol-gel synthesis

    Science.gov (United States)

    Carnes, Corrie Leigh

    The goal of this research was to synthesize, characterize and study the chemical properties of nanocrystalline metal oxides. Nanocrystalline (NC) ZnO, CuO, NiO, Al2O3, and the binary Al2O 3/MgO and ZnO/CuO were prepared through modified sol gel methods. These NC metal oxides were studied in comparison to the commercial (CM) metal oxides. The samples were characterized by XRD, TGA, FTIR, BET, and TEM. The NC samples were all accompanied by a significant increase in surface area and decrease in crystallite size. Several chemical reactions were studied to compare the NC samples to the CM samples. One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride. A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. A room temperature gas phase adsorption was studied where SO2 was adsorbed onto the oxide. A liquid phase adsorption conducted at room temperature was the destructive adsorption of paraoxon (a toxic insecticide). In all reactions the NC samples exhibited greater activity, destroying or adsorbing a larger amount of the toxins compared to the CM samples. To better study surface area effects catalytic reactions were also studied. The catalysis of methanol was studied over the nanocrystalline ZnO, CuO, NiO, and ZnO/CuO samples in comparison to their commercial counterparts. In most cases the NC samples proved to be more active catalysts, having higher percent conversions and turnover numbers. A second catalytic reaction was also studied, this reaction was investigated to look at the support effects. The catalysis of cyclopropane to propane was studied over Pt and Co catalysts. These catalysts were supported onto NC and CM alumina by impregnation. By observing differences in the catalytic behavior, support effects have become apparent.

  12. Electrical Properties of Ba3Ca1.18Nb1.82O9-  Proton-Conducting Electrolyte Prepared by a Combustion Method

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    chemical route for preparing BCN18 powders that were then sintered into pellets. Electrochemical impedance spectroscopy studies indicated that BCN18 pellets show proton conductivity, since their total conductivity in wet air was significantly larger than

  13. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  14. Introduction to wetting phenomena

    International Nuclear Information System (INIS)

    Indekeu, J.O.

    1995-01-01

    In these lectures the field of wetting phenomena is introduced from the point of view of statistical physics. The phase transition from partial to complete wetting is discussed and examples of relevant experiments in binary liquid mixtures are given. Cahn's concept of critical-point wetting is examined in detail. Finally, a connection is drawn between wetting near bulk criticality and the universality classes of surface critical phenomena. (author)

  15. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent

  16. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Dolfine Kosters, N.; Daanen, h.a.m.; Kappers, A.M.L.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the me-chanics of wetness perception. This paper describes an experiment with six conditions regarding haptic dis-crimination of the wetness of fabrics. Three materials were used: cotton wool,

  17. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, Astrid M.L.; Daanen, H.A.M.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the mechanics of wetness perception. This paper describes an experiment with six conditions regarding haptic discrimination of the wetness of fabrics. Three materials were used: cotton wool,

  18. Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder.

    Science.gov (United States)

    Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana

    2011-02-01

    Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin content in pink powder decreased from 50.5 to 11.2 and 14.1 mg/100 g in samples packed in polyethylene (PE) and metalised polyester polyethylene laminated pouches respectively. Total polyphenol amount increased in both the powders irrespective of packaging material. Sorption isotherms indicated that both white and pink aril powders were hygroscopic and equilibrated at low relative humidity of 28 and 32%, respectively.

  19. Chemical preparation of biological materials for accurate chromium determination by isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Dunstan, L.P.; Garner, E.L.

    1977-01-01

    The current interest in trace elements in biological materials has created a need for accurate methods of analysis. The source of discrepancies and variations in chromium concentration determinations is often traceable to inadequate methods of sample preparation. Any method of Cr analysis that requires acid digestion of a biological matrix must take into consideration the existence or formation of a volatile Cr component. In addition, because Cr is often present at concentrations less than 1 μg/g, the analytical blank becomes a potential source of error. Chemical procedures have been developed for the digestion of the biological matrix and the separation of Cr without either large analytical blanks or significant losses by volatilization. These procedures have been used for the analysis of NBS Standard Reference Material (SRM) 1569 Brewers Yeast; SRM 1577 Bovine Liver; SRM 1570 Spinach and other biological materials including human hair and nails. At this time, samples containing 1 μg of Cr can be determined with an estimated accuracy of 2 percent

  20. Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Gates, S. M.; Neumayer, D. A.; Sherwood, M. H.; Grill, A.; Wang, X.; Sankarapandian, M.

    2007-01-01

    The preparation of ultralow dielectric constant porous silicon, carbon, oxygen, hydrogen alloy dielectrics, called 'pSiCOH', using a production 200 mm plasma enhanced chemical vapor deposition tool and a thermal treatment is reported here. The effect of deposition temperature on the pSiCOH film is examined using Fourier transform infrared (FTIR) spectroscopy, dielectric constant (k), and film shrinkage measurements. For all deposition temperatures, carbon in the final porous film is shown to be predominantly Si-CH 3 species, and lower k is shown to correlate with increased concentration of Si-CH 3 . NMR and FTIR spectroscopies clearly detect the loss of a removable, unstable, hydrocarbon (CH x ) phase during the thermal treatment. Also detected are increased cross-linking of the Si-O skeleton, and concentration changes for three distinct structures of carbon. In the as deposited films, deposition temperature also affects the hydrocarbon (CH x ) content and the presence of C=O and C=C functional groups

  1. Preparation and physico-chemical properties of hydrogels from carboxymethyl cassava starch crosslinked with citric acid

    Science.gov (United States)

    Boonkham, Sasikan; Sangseethong, Kunruedee; Chatakanon, Pathama; Niamnuy, Chalida; Nakasaki, Kiyohiko; Sriroth, Klanarong

    2014-06-01

    Recently, environmentally friendly hydrogels prepared from renewable bio-based resources have drawn significant attention from both industrial and academic sectors. In this study, chemically crosslinked hydrogels have been developed from cassava starch which is a bio-based polymer using a non-toxic citric acid as a crosslinking agent. Cassava starch was first modified by carboxymethylation to improve its water absorbency property. The carboxymethyl cassava starch (CMCS) obtained was then crosslinked with citric acid at different concentrations and reaction times. The gel fraction of hydrogels increased progressively with increasing citric acid concentration. Free swelling capacity of hydrogels in de-ionized water, saline solution and buffers at various pHs as well as absorption under load were investigated. The results revealed that swelling behavior and mechanical characteristic of hydrogels depended on the citric acid concentration used in reaction. Increasing citric acid concentration resulted in hydrogels with stronger network but lower swelling and absorption capacity. The cassava starch hydrogels developed were sensitive to ionic strength and pH of surrounding medium, showing much reduced swelling capacity in saline salt solution and acidic buffers.

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

    Directory of Open Access Journals (Sweden)

    Erki Kärber

    2014-12-01

    Full Text Available Solar cells consisting of an extremely thin In2S3/CuInS2 buffer/absorber layer uniformly covering planar ZnO were prepared entirely by chemical spray pyrolysis. Au nanoparticles (Au-NPs were formed via thermal decomposition of a gold(III chloride trihydrate (HAuCl4·3H2O precursor by spraying 2 mmol/L of the aqueous precursor solution onto a substrate held at 260 °C. Current–voltage scans and external quantum efficiency spectra were used to evaluate the solar cell performance. This work investigates the effect of the location of the Au-NP layer deposition (front side vs rear side in the solar cell and the effect of varying the volume (2.5–10 mL of the sprayed Au precursor solution. A 63% increase (from 4.6 to 7.5 mA/cm2 of the short-circuit current density was observed when 2.5 mL of the precursor solution was deposited onto the rear side of the solar cell.

  3. Thermal shock behavior of W-0.5 wt% Y{sub 2}O{sub 3} alloy prepared via a novel chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Mei-Ling [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Luo, Lai-Ma, E-mail: luolaima@126.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China); Lin, Jing-Shan [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zan, Xiang; Zhu, Xiao-Yong [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China); Luo, Guang-Nan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu, Yu-Cheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National-Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China)

    2016-10-15

    A wet-chemical method combined with spark plasma sintering was used to prepare W-0.5 wt% Y{sub 2}O{sub 3} alloy. The W-0.5 wt% Y{sub 2}O{sub 3} precursor was reduced at 800 °C for 4 h under different hydrogen flow rates of 300, 400, 500, 600, and 700 ml/min. The reduced powder was analyzed by X-ray diffraction (XRD), laser particle size analyzer (LPSA), and scanning electron microscopy (SEM). An optimized process for reducing precursor was discussed. After sintering, the specimens were exposed to different laser beam irradiation energies (90, 120, 150, and 180 W) to simulate loads as expected for edge localized modes (ELMs). Top surface and cross-sectional morphology were observed by SEM, and the changes in hardness were evaluated. The changes in microstructural properties (i.e., Y{sub 2}O{sub 3}-particle distribution, crack propagation direction, depth of thermal shock effect, and grain size of the recrystallization region) after thermal shock were investigated.

  4. Thermal shock behavior of W-0.5 wt% Y_2O_3 alloy prepared via a novel chemical method

    International Nuclear Information System (INIS)

    Zhao, Mei-Ling; Luo, Lai-Ma; Lin, Jing-Shan; Zan, Xiang; Zhu, Xiao-Yong; Luo, Guang-Nan; Wu, Yu-Cheng

    2016-01-01

    A wet-chemical method combined with spark plasma sintering was used to prepare W-0.5 wt% Y_2O_3 alloy. The W-0.5 wt% Y_2O_3 precursor was reduced at 800 °C for 4 h under different hydrogen flow rates of 300, 400, 500, 600, and 700 ml/min. The reduced powder was analyzed by X-ray diffraction (XRD), laser particle size analyzer (LPSA), and scanning electron microscopy (SEM). An optimized process for reducing precursor was discussed. After sintering, the specimens were exposed to different laser beam irradiation energies (90, 120, 150, and 180 W) to simulate loads as expected for edge localized modes (ELMs). Top surface and cross-sectional morphology were observed by SEM, and the changes in hardness were evaluated. The changes in microstructural properties (i.e., Y_2O_3-particle distribution, crack propagation direction, depth of thermal shock effect, and grain size of the recrystallization region) after thermal shock were investigated.

  5. Pine growth and plant community response to chemical vs. mechanical site preparation for establishing loblolly and slash pine

    Science.gov (United States)

    James H. Miller; Zhijuan Qiu

    1995-01-01

    Chemical and mechanical site preparation methods were studied for establishing loblolly (Pinus taeda L) and slash (P. elliottii var. elliottii Engelm.) pine following both integrated fuelwood-pulpwood harvesting and conventional whole-tree harvesting of pines and hardwoods in southem Alabama's Middle Coastal...

  6. A comparison of properties between carboxylated acrylic rubbers prepared by γ-ray irradiation and chemical method

    International Nuclear Information System (INIS)

    Wang Weiwei; Chang Zhenqi; Wang Mozhen; Zhang Zhicheng; Lv Pin

    2006-01-01

    Acrylic rubbers (ACM) carboxylated by acrylic acid or itaconic acid were prepared by 60 Co γ-ray or chemical-initiator (K 2 S 2 O 8 ) induced emulsion copolymerization. The polymers were characterized by Fourier transform infrared spectroscopy (FT-IR). Acid value, molecular weight and polydispersity index (PDI) of the polymers were determined by non-aqueous titration method and gel permeation chromatography (GPC), respectively. Vulcanization and mechanical properties of the filled ACM were studied by rheometric measurement, gel fraction analysis, mechanical property tests and dynamic mechanical thermal analysis (DMTA). The results show that the ACMs prepared by γ-ray irradiation have lower acid value, higher molecular weight and narrower PDI than chemically prepared ACMs of the same compositions. The itaconic acid carboxylated ACM has better cure characteristics and mechanical properties than the acrylic acid carboxylated ACM. The itaconic acid carboxylated ACM prepared by γ-ray irradiation has higher gel fraction and better cure characteristics as well as mechanical properties than that prepared by chemical method. (authors)

  7. The effects of banana peel preparations on the properties of banana peel dietary fibre concentrate

    Directory of Open Access Journals (Sweden)

    Phatcharaporn Wachirasiri

    2010-01-01

    Full Text Available Four different preparation methods of banana peel, dry milling, wet milling, wet milling and tap water washing, and wet milling and hot water washing were investigated on their effects on the chemical composition and properties of the banana peel dietary fibre concentrate (BDFC. The dry milling process gave the BDFC a significant higher fat, protein, and starch content than the wet milling process, resulting in a lower water holding capacity (WHC and oil holding capacity(OHC. Washing after wet milling could enhance the concentration of total dietary fibre by improving the removal of protein and fat. Washing with hot water after wet milling process caused a higher loss of soluble fibre fraction, resulting in a lower WHC and OHC of the obtained BDFC when compared to washing with tap water. Wet milling and tap water washing gave the BDFC the highest concentration of total and soluble dietary fibre, WHC and OHC.

  8. Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

    Energy Technology Data Exchange (ETDEWEB)

    AfzaliTabar, M. [Department of Chemistry, Islamic Azad University Branch of Tehran North, Tehran (Iran, Islamic Republic of); Alaei, M., E-mail: alaiem@ripi.ir [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Ranjineh Khojasteh, R.; Motiee, F. [Department of Chemistry, Islamic Azad University Branch of Tehran North, Tehran (Iran, Islamic Republic of); Rashidi, A.M. [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of)

    2017-01-15

    The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO{sub 2} nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated using optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO{sub 2} nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO{sub 2} nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO{sub 2} nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).

  9. Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

    International Nuclear Information System (INIS)

    AfzaliTabar, M.; Alaei, M.; Ranjineh Khojasteh, R.; Motiee, F.; Rashidi, A.M.

    2017-01-01

    The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO 2 nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated using optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO 2 nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO 2 nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO 2 nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).

  10. Ethnopharmacological and Chemical Characterization of Salvia Species Used in Valencian Traditional Herbal Preparations

    Directory of Open Access Journals (Sweden)

    Vanessa Martínez-Francés

    2017-07-01

    Full Text Available In Valencia Region (Spain, some wild and cultivated sages are used for medicinal purposes. Among them, Salvia officinalis subsp. lavandulifolia (SL is widely employed and known for production of Spanish sage oil and herbal products. Nevertheless, it shares the market with S. blancoana subsp. mariolensis (SB and, to a lesser extent, with their hybrid S. x hegelmaieri (SH. The knowledge on these two species is far low and confusion between them is possible. The aim of the present paper is to improve the ethnopharmacological, morphological and chemical knowledge of these sages, and to contribute to setting up quality specifications for improving identification and distinction from other Salvia species, such as, S. officinalis subsp. officinalis, S. x auriculata and S. microphylla var. microphylla. Samples were collected in Valencia Region and surrounding mountain areas during the ethnopharmacological field work. Twenty-nine medicinal uses were reported for SL, 13 of them being also recorded for SB. Of particular interest is a homemade liquor, used as digestive and known as “salvieta,” which is mainly prepared with SB. The macro- and microscopic characters are insufficient for identification of cut, crushed or powdered material. The study of the essential oil and a HPTLC (High Performance Thin Layer Chromatography fingerprint of their extracts could help to distinguish SB from the other sages. The essential oil from dried aerial parts of SB (content: 1.8–4.5% was characterized by GC-FID (Gas Chromatography with Flame Ionization Detector and GC-MS (Gas Chromatography coupled to Mass Spectrometry showing a composition close to that currently accepted for Spanish sage essential oil in the European Pharmacopoeia, ISO (International Standard Organization and UNE (Una Norma Española standards, with 1,8-cineole (13.7–45.7% and camphor (12.1–28.6% as major constituents. HPTLC methods, based on the analysis of hydroalcoholic and dichloromethane

  11. Control of oil-wetting on technical textiles by means of photo-chemical surface modification and its relevance to the performance of compressed air filters

    International Nuclear Information System (INIS)

    Bahners, Thomas; Mölter-Siemens, Wolfgang; Haep, Stefan; Gutmann, Jochen S.

    2014-01-01

    Highlights: • The oil repellence of textile fabrics was increased following the Wenzel concept. • Fiber surfaces were micro-roughened by means of pulsed UV laser irradiation. • Subsequent UV-induced grafting yielded pronounced oil repellence. • The grafting process conserved the delicate topography of the fiber surfaces. • The modified fabrics showed favorable drainage behavior in oil droplet separation. - Abstract: A two-step process comprising a surface roughening step by excimer laser irradiation and a post-treatment by photo-grafting to decrease the surface free energy was employed to increase the oil repellence of technical fabrics made of poly(ethylene terephthalate) (PET). The modification was designed to improve the performance of multi-layer filters for compressed air filtration, in which the fabrics served to remove, i.e. drain, oil separated from the air stream. In detail, the fibers surfaces were roughened by applying several laser pulses at a wavelength of 248 nm and subsequently photo-grafted with 1H,1H,2H,2H-perfluoro-decyl acrylate (PPFDA). The oil wetting behavior was increased by the treatments from full wetting on the as-received fabrics to highly repellent with oil contact angles of (131 ± 7)°. On surfaces in the latter state, oil droplets did not spread or penetrate even after one day. The grafting of PPFDA alone without any surface roughening yielded an oil contact angle of (97 ± 11)°. However, the droplet completely penetrated the fabric over a period of one day. The drainage performance was characterized by recording the pressure drop over a two-layer model filter as a function of time. The results proved the potential of the treatment, which reduced the flow resistance after 1-h operation by approximately 25%

  12. Preparing for chemical terrorism: a study of the stability of expired pralidoxime (2-PAM).

    Science.gov (United States)

    Hoffman, Robert S; Mercurio-Zappala, Maria; Bouchard, Nicole; Ravikumar, Padinjarekuttu; Goldfrank, Lewis

    2012-03-01

    Oximes such as pralidoxime (2-PAM) are essential antidotes for life-threatening organophosphate poisoning. Unfortunately, oximes are expensive, have limited use, and have short shelf lives. As such, maintaining large stockpiles in preparation for terrorist activity is not always possible. We have demonstrated that atropine is stable well beyond its labeled shelf life and that recently expired 2-PAM was clinically efficacious in a series of poisoned patients. Because 2-PAM is often dosed empirically, clinical improvement does not guarantee pharmacological stability. We therefore chose to analyze the chemical stability of expired 2-PAM. Samples of lyophylized 2-PAM were maintained according to the manufacturer's recommendations for 20 years beyond the published shelf life. We studied 2-PAM contained in a MARK I autoinjector that was stored properly for 3 years beyond its expiration date. An Agilent LC/MSD 1100 with diode-array detector and an Agilent Sorbax SB-C-18, 4.6 × 150-mm, 5-μm column were used with the following solvent systems: water with 0.01% trifluoroacetic acid and methanol with 0.01% trifluoroacetic acid. Fresh reagent grade 2-PAM was used as a standard. Results were repeated for consistency. Lyophylized 2-PAM was a white powder that was clear and colorless in solution. Liquid chromatography was identical to the standard and resulted in 2 isolated peaks with identical mass spectra, suggesting that they are stereoisomers. The autoinjector discharged a clear, yellowish solution. In addition to the 2 peaks identified for lyophylized 2-PAM, a small third peak was identified with a mass spectra corresponding to the reported N -methyl pyridinium carboxaldehyde degradation product. When properly stored, lyophylized 2-PAM appears to be chemically stable well beyond its expiration date. Although the relative amount of degradation product found in solubilized (autoinjector) 2-PAM was small, it is unclear whether this may be toxic and therefore is of concern

  13. High coercivity Gd-substituted Ba hexaferrites, prepared by chemical coprecipitation

    Science.gov (United States)

    Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

    2008-04-01

    A series of Gd-substituted Ba hexaferrites with nominal formula (Ba1-xGdx)Oṡ5.25 Fe2O3 (x=0-0.30) were prepared by the chemical coprecipitation method from nitrate precursors and heating at T =800-1200°C for 2h. The samples have been examined by x-ray diffraction, vibrating-sample magnetometer, and scanning electron microscopy methods. Gd substituted samples form single phase materials with the M-type hexaferrite structure at all heating temperatures, in the range of x ⩽0.10-0.20. The saturation magnetization (at 1.8T) varies slightly with x in most cases and, for x =0.05-0.10, it increases up to 66.7Am2/kg, exceeding the value of the unsubstituted hexaferrite. A strong enhancement of the coercivity is observed for all substituted samples, with maximum values Hc=457kA/m for the single-phase x =0.10 sample annealed at 1000°C and Hc=477kA/m for the x =0.25 sample annealed at 1100°C which contains Fe2O3 and GdFeO3 impurities. As the variation of coercivity with either substitution rate (x ) or annealing temperature is not monotonic, three different factors may account for the high coercivities that are obtained: (a) an inhibition of grain growth due to the presence of Gd, (b) a possible inherent effect on magnetocrystalline anisotropy, especially for single phase samples, and (c) a microstructural effect of secondary phases.

  14. PREFACE: Wetting: introductory note

    Science.gov (United States)

    Herminghaus, S.

    2005-03-01

    of very specific and quantitative predictions were put forward which were aimed at direct experimental tests of the developed concepts [9]. Experimentally, wetting phenomena proved to be a rather difficult field of research. While contact angles seem quite easy to measure, deeper insight can only be gained by assessing the physical properties of minute amounts of material, as provided by the molecularly thin wetting layers. At the same time, the variations in the chemical potential relevant for studying wetting transitions are very small, such that system stability sometimes poses hard to solve practical problems. As a consequence, layering transitions in cryogenic systems were among the first to be thoroughly studied [10] experimentally, since they require comparably moderate stability. First-order wetting transitions were not observed experimentally before the early nineties, either in (cryogenic) quantum systems [11,12] or in binary liquid mixtures [13,14]. The first observation of critical wetting, a continuous wetting transition, in 1996 [15] was a major breakthrough [16]. In the meantime, a detailed seminal paper by Pierre Gilles de Gennes published in 1985 [17] had spurred a large number of new research projects which were directed to wetting phenomena other than those related to phase transitions. More attention was paid to non-equilibrium physics, as it is at work when oil spreads over a surface, or a liquid coating beads off (`dewets') from its support and forms a pattern of many individual droplets. This turned out to be an extremely fruitful field of research, and was more readily complemented by experimental efforts than was the case with wetting transitions. It was encouraging to find effects analogous to layering (as mentioned above) in more common systems such as oil films spreading on a solid support [18,19]. Long standing riddles such as the divergence of dissipation at a moving contact line were now addressed both theoretically and experimentally

  15. Preparation and chemical characteristics of Karunguruvai Khadi used in the traditional Siddha formulation of herbo-mineral-based medicine

    Directory of Open Access Journals (Sweden)

    Eleza Chellakkan

    2016-01-01

    Conclusion: The result of the chemical analysis of Khadi extracts showed that Khadi prepared from the Karunguruvai paddy grains (rice was the best base solvent for ion exchange in the preparation of muppu than Samba Khadi. The analysis of the composition of these two types of Karunguruvai Khadi show that it is a good solvent for the elimination of heavy metals and for the enrichment of elements in Pooneeru powder (muppu, the chuurnam of Siddha drugs. These characteristics enhance the therapeutic potential and safety of the drugs for healing chronic diseases.

  16. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se)2 based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    International Nuclear Information System (INIS)

    Hönes, C.; Hackenberg, J.; Zweigart, S.; Wachau, A.; Hergert, F.; Siebentritt, S.

    2015-01-01

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se 2 based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se) 2 based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects

  17. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Hönes, C., E-mail: christian.hoenes@de.bosch.com [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Hackenberg, J. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Zweigart, S. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Postfach 10 60 50, D-70049 Stuttgart (Germany); Wachau, A.; Hergert, F. [Bosch Solar CISTech GmbH, D-14772 Brandenburg (Germany); Siebentritt, S., E-mail: susanne.siebentritt@uni.lu [Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg)

    2015-03-07

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se{sub 2} based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects.

  18. Wet Gas Airfoil Analyses

    OpenAIRE

    Larsen, Tarjei Thorrud

    2011-01-01

    Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was ...

  19. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V; Lindholm, J; Nurmi, M; Naesman, J [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B; Konn, J; Sundberg, A; Willfoer, S [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1999-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  20. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V.; Lindholm, J.; Nurmi, M.; Naesman, J. [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B.; Konn, J.; Sundberg, A.; Willfoer, S. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1998-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  1. Physical-chemical and biological characterization of different preparations of equine chorionic gonadotropin

    OpenAIRE

    Alvarez, Rafael Herrera; Natal, Fabio Luis Nogueira; Ribela, Maria Teresa Carvalho Pinto; de Almeida, Beatriz Elane; de Oliveira, Jo?o Ezequiel; Bartolini, Paolo

    2016-01-01

    Ovarian stimulation with commercial preparations of equine chorionic gonadotropin (eCG) produces extremely variable responses in domestic animals, ranging from excessive stimulation to practically no stimulation, when applied on the basis of their declared unitage. This study was conducted to analyze four commercial preparations from different manufacturers via reversed-phase HPLC (RP-HPLC) in comparison with a reference preparation and an official International Standard from the World Health...

  2. Hydrogen evolution under visible light over LaCoO3 prepared by chemical route

    International Nuclear Information System (INIS)

    Meziani, D.; Reziga, A.; Rekhila, G.; Bellal, B.; Trari, M.

    2014-01-01

    Highlights: • Visible-light hydrogen evolution is achieved on the hetero-system LaCoO 3 /SnO 2 . • The crystal field splits the Co 3+ : 3d orbital by a value of 2.05 eV. • The capacitance plot shows p-type conduction with flat band potential of 0 V SCE. • The photo-electrochemistry yields a valence and conduction bands of 3d parentage. - Abstract: The semiconducting properties of the perovskite LaCoO 3 , prepared by nitrate route, are investigated for the first time by the photo-electrochemical technique. The oxide shows a direct optical transition at 1.33 eV, due to Co 3+ : 3d orbital splitting in octahedral site and possesses a chemical stability over a fair pH range (4–14). The conductivity follows an exponential type law with a hole mobility (8.3 × 10 −2 cm 2 V −1 s −1 ), thermally activated. The Mott–Schottky plot in KOH medium is characteristic of p type conduction with a flat band potential of 0 V SCE and a holes density of 1.35 × 10 17 cm −3 . The electrochemical impedance spectroscopy reveals the predominance of the bulk and grains boundaries contributions with a constant phase element and a multi-relaxation type nature. As application, the hydrogen evolution upon visible light is demonstrated on the hetero-junction LaCoO 3 /SnO 2 . The best performance occurs at pH ∼ 12.8 with an evolution rate of 0.25 cm 3 min −1 (mg LaCoO 3 ) −1 and a quantum yield of 0.11%. The improved activity is attributed to the wide depletion width of ∼10 nm and the potential of the conduction band of LaCoO 3 (−1.34 V SCE ), more negative than that of SnO 2 , the latter acts as electrons bridge for the interfacial water reduction. The relevance of 3d orbital of the performance of semi conducting photoelectrode is discussed

  3. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    International Nuclear Information System (INIS)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon

    2015-01-01

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H 3 PO 4 , HCl, and HNO 3 are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO 3 exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10 −4 Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H 3 PO 4 , HCl and HNO 3 were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO 3 -etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm 2 and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO 3 -etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO 3 -etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%

  4. Characterizations on the microstructures of LiMn2O4 prepared by a simple soft-chemical technique

    International Nuclear Information System (INIS)

    Wei Yingjin; Kim, Kwang Bum; Chen Gang; Park, Chul W.

    2008-01-01

    LiMn 2 O 4 powders were prepared by a simple soft-chemical technique at different temperatures. X-ray diffraction and thermogravimetric analysis suggested that the material prepared at 800 deg. C was stoichiometric LiMn 2 O 4 , whereas those prepared at 600 and 700 deg. C were Li[Mn 0.77 3+ Mn 1.23 4+ ]O 4.115 and Li[Mn 0.85 3+ Mn 1.15 4+ ]O 4.075 . Several typical XRD peaks of the compounds were investigated with an aim to elucidate (i) the Li immigration to the 16d octahedral sites, (ii) the partial tetragonal phase transition of the material and (iii) the mean coherent domain size and microstrain. SEM study showed that the particle size of the materials increased with heating temperature. The activation energy for the material particle growth was determined as 30.4 kJ mol -1

  5. Final status report in preparation for the chemical cleaning of Dresden-1, DNS-D1-034

    International Nuclear Information System (INIS)

    1981-09-01

    This report discusses the status of all of the activities conducted in preparation for the chemical cleaning of the Dresden-1 Nuclear Power Plant of Commonwealth Edison of Illinois. The metallurgical testing of a solvent and its ability to remove radioactivity are reviewed. Included are all engineering details relating to the modifications to the primary system to be able to perform the chemical cleaning and to rinse the cleaning solvent out of the equipment. A facility to store and process spent cleaning solutions is described in detail. Construction activities and preoperational activities are recounted. Licensing activities, quality assurance, safety, and radiation protection are discussed. The report includes recommendations for future actions for restarting the project when approval is received. All of the efforts discussed in this Final Status Report led to the conclusion that the chemical cleaning, as planned, was feasible. All of the necessary modifications and new equipment are in place and are operational

  6. Particle-assisted wetting

    International Nuclear Information System (INIS)

    Xu Hui; Yan Feng; Tierno, Pietro; Marczewski, Dawid; Goedel, Werner A

    2005-01-01

    Wetting of a solid surface by a liquid is dramatically impeded if either the solid or the liquid is decorated by particles. Here it is shown that in the case of contact between two liquids the opposite effect may occur; mixtures of a hydrophobic liquid and suitable particles form wetting layers on a water surface though the liquid alone is non-wetting. In these wetting layers, the particles adsorb to, and partially penetrate through, the liquid/air and/or the liquid/water interface. This formation of wetting layers can be explained by the reduction in total interfacial energy due to the replacement of part of the fluid/fluid interfaces by the particles. It is most prominent if the contact angles at the fluid/fluid/particle contact lines are close to 90 0

  7. Fluorine- and iron-modified hierarchical anatase microsphere photocatalyst for water cleaning: facile wet chemical synthesis and wavelength-sensitive photocatalytic reactivity.

    Science.gov (United States)

    Liu, Shaohong; Sun, Xudong; Li, Ji-Guang; Li, Xiaodong; Xiu, Zhimeng; Yang, He; Xue, Xiangxin

    2010-03-16

    High photocatalytic efficiency, easy recovery, and no biological toxicity are three key properties related to the practical application of anatase photocatalyst in water cleaning, but seem to be incompatible. Nanoparticles-constructed hierarchical anatase microspheres with high crystallinity and good dispersion prepared in this study via one-step solution processing at 90 degrees C under atmospheric pressure by using ammonium fluotitanate as the titanium source and urea as the precipitant can reconcile these three requirements. The hierarchical microspheres were found to grow via an aggregative mechanism, and contact recrystallization occurred at high additions of the FeCl(3) electrolyte into the reaction system. Simultaneous incorporation of fluorine and iron into the TiO(2) matrix was confirmed by combined analysis of X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Surface structure and morphology changes of the microspheres induced by high-temperature annealing were clearly observed by field-emission scanning electron microscopy, especially for the phase-transformed particles. The original nanoparticles-constructed rough surfaces partially became smooth, resulting in a sharp drop in photocatalytic efficiency. Interestingly, iron loading has detrimental effects on the visible-light photocatalytic activity of both the as-prepared and the postannealed anatase microspheres but greatly enhances the photocatalytic activity of the as-prepared anatase microspheres under UV irradiation. No matter under UV or visible-light irradiation, the fluorine-loaded anatase microspheres and especially the postannealed ones show excellent photocatalytic performance. The underlying mechanism of fluorine and iron loading on the photocatalytic efficacy of the anatase microspheres was discussed in detail. Beyond photocatalytic applications, this kind of material is of great importance to the assembling of

  8. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw

    2015-06-15

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H{sub 3}PO{sub 4}, HCl, and HNO{sub 3} are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO{sub 3} exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10{sup −4} Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H{sub 3}PO{sub 4}, HCl and HNO{sub 3} were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm{sup 2} and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO{sub 3}-etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%.

  9. Chemical Peels

    Science.gov (United States)

    ... care Kids’ zone Video library Find a dermatologist Chemical peels Overview Chemical peels: Overview Also called chemexfoliation , derma peeling Do ... Overview Chemical peels: FAQs Chemical peels: Preparation FAQs Chemical peels: FAQs To help you decide whether this ...

  10. Preparation and chemical crystallographic study of new hydrides and hydro-fluorides of ionic character; Preparation et etude cristallochimique de nouveaux hydrures et fluorohydrures a caractere ionique

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung-Ho

    1988-07-22

    Within the context of a growing interest in the study of reversible hydrides with the perspective of their application in hydrogen storage, this research thesis more particularly addressed the case of ternary hydrides and fluorides, and of hydro-fluorides. The author reports the development of a method of preparation of alkaline hydrides, of alkaline earth hydrides and of europium hydride, and then the elaboration of ternary hydrides. He addresses the preparation of caesium fluorides and of calcium or nickel fluorides, of Europium fluorides, and of ternary fluorides. Then, he addresses the preparation of hydro-fluorides (caesium, calcium, europium fluorides, and caesium and nickel fluorides). The author presents the various experimental techniques: chemical analysis, radio-crystallographic analysis, volumetric mass density measurement, magnetic measurements, ionic conductivity measurements, Moessbauer spectroscopy, and nuclear magnetic resonance. He reports the crystallographic study of some ternary alkaline and alkaline-earth hydrides (KH-MgH{sub 2}, RbH-CaH{sub 2}, CsH-CaH{sub 2}, RbH-MgH{sub 2} and CsH-MgH{sub 2}) and of some hydro-fluorides (CsCaF{sub 2}H, EuF{sub 2}H, CsNiF{sub 2}H) [French] Dans une premiere partie, de nouveaux hydrures ternaires ont ete prepares et caracterises. Les systemes etudies sont AH-MH 2 (A = K, Rb, Cs et M = Mg, Ca). Dans les systemes AH-MgH 2 l'evolution structurale a ete discutee en fonction du caractere iono-covalent de la liaison magnesium-hydrogene. Dans une deuxieme partie, plusieurs nouveaux fluorohydrures ont ete mis en evidence. L'effet de la substitution de l'hydrogene au fluor dans ces phases a ete etudiee en utilisant la RMN, la spectroscopie Moessbauer, la conductivite ionique et les mesures magnetiques.

  11. Chemical Weapons: FEMA and Army Must Be Proactive in Preparing States for Emergencies

    National Research Council Canada - National Science Library

    2001-01-01

    .... Such an accident could affect people in 10 different states. The Army plans to destroy its entire chemical weapons stockpile by 2007 and is taking measures to protect the public before and during the demilitarization process...

  12. 78 FR 4446 - Exempt Chemical Preparations Under the Controlled Substances Act

    Science.gov (United States)

    2013-01-22

    ... TOXI-LAB DISCS LTD HD Plastic vial: 50 discs... 12/22/2011 Agilent Technologies TOXI-LAB DISCS LTD OP... Chemicals, Inc... (+)-iodo-Lysergic Acid Vial: 1 mL 12/22/2011 diethylamide [125I]. American Radiolabeled.../2011 (1 mg/mL). American Radiolabeled Chemicals, Inc... Lysergic Acid (1 mg/mL)........ Vial: 1 mL 12...

  13. The influence of reaction times on structural, optical and luminescence properties of cadmium telluride nanoparticles prepared by wet-chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Kiprotich, Sharon, E-mail: KiprotichS@qwa.ufs.ac.za [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Dejene, Francis B.; Ungula, Jatani [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Onani, Martin O. [Departments of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2016-01-01

    This paper explains one pot synthesis of type II water soluble L-cysteine capped cadmium telluride (CdTe) core shell quantum dots using cadmium acetate, potassium tellurite and L-cysteine as the starting materials. The reaction was carried out in a single three necked flask without nitrogen under reflux at 100 °C. Results from PL show a sharp absorption excitonic band edge of the CdTe core with respect to the core shell which loses its shoulder during the growth of the shell on the core. The PL spectra indicate a drastic shift in emission window of the core which is simultaneously accompanied by an increase in emission intensity. X-ray diffraction pattern confirms the formation of hexagonal phase for all samples. Some difference in absorption edges were observed due to varying synthesis time of CdTe NPs. The position of the absorption band is observed to shift towards the lower wavelength side for shorter durations of synthesis.

  14. A Wet Chemistry Laboratory Cell

    Science.gov (United States)

    2008-01-01

    This picture of NASA's Phoenix Mars Lander's Wet Chemistry Laboratory (WCL) cell is labeled with components responsible for mixing Martian soil with water from Earth, adding chemicals and measuring the solution chemistry. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  15. Erosion corrosion in wet steam

    International Nuclear Information System (INIS)

    Tavast, J.

    1988-03-01

    The effect of different remedies against erosion corrosion in wet steam has been studied in Barsebaeck 1. Accessible steam systems were inspected in 1984, 1985 and 1986. The effect of hydrogen peroxide injection of the transport of corrosion products in the condensate and feed water systems has also been followed through chemical analyses. The most important results of the project are: - Low alloy chromium steels with a chromium content of 1-2% have shown excellent resistance to erosion corrosion in wet steam. - A thermally sprayed coating has shown good resistance to erosion corrosion in wet steam. In a few areas with restricted accessibility minor attacks have been found. A thermally sprayed aluminium oxide coating has given poor results. - Large areas in the moisture separator/reheater and in steam extraction no. 3 have been passivated by injection of 20 ppb hydrogen peroxide to the high pressure steam. In other inspected systems no significant effect was found. Measurements of the wall thickness in steam extraction no. 3 showed a reduced rate of attack. - The injection of 20 ppb hydrogen peroxide has not resulted in any significant reduction of the iron level result is contrary to that of earlier tests. An increase to 40 ppb resulted in a slight decrease of the iron level. - None of the feared disadvantages with hydrogen peroxide injection has been observed. The chromium and cobalt levels did not increase during the injection. Neither did the lifetime of the precoat condensate filters decrease. (author)

  16. Quantitative and simultaneous analysis of the polarity of polycrystalline ZnO seed layers and related nanowires grown by wet chemical deposition

    Science.gov (United States)

    Guillemin, Sophie; Parize, Romain; Carabetta, Joseph; Cantelli, Valentina; Albertini, David; Gautier, Brice; Brémond, Georges; Fong, Dillon D.; Renevier, Hubert; Consonni, Vincent

    2017-03-01

    The polarity in ZnO nanowires is an important issue since it strongly affects surface configuration and reactivity, nucleation and growth, electro-optical properties, and nanoscale-engineering device performances. However, measuring statistically the polarity of ZnO nanowire arrays grown by chemical bath deposition and elucidating its correlation with the polarity of the underneath polycrystalline ZnO seed layer grown by the sol-gel process represents a major difficulty. To address that issue, we combine resonant x-ray diffraction (XRD) at Zn K-edge using synchrotron radiation with piezoelectric force microscopy and polarity-sensitive chemical etching to statistically investigate the polarity of more than 107 nano-objects both on the macroscopic and local microscopic scales, respectively. By using high temperature annealing under an argon atmosphere, it is shown that the compact, highly c-axis oriented ZnO seed layer is more than 92% Zn-polar and that only a few small O-polar ZnO grains with an amount less than 8% are formed. Correlatively, the resulting ZnO nanowires are also found to be Zn-polar, indicating that their polarity is transferred from the c-axis oriented ZnO grains acting as nucleation sites in the seed layer. These findings pave the way for the development of new strategies to form unipolar ZnO nanowire arrays as a requirement for a number of nanoscale-engineering devices like piezoelectric nanogenerators. They also highlight the great advantage of resonant XRD as a macroscopic, non-destructive method to simultaneously and statistically measure the polarity of ZnO nanowire arrays and of the underneath ZnO seed layer.

  17. Polycrystalline and Mesoporous 3-D Bi2O3 Nanostructured Negatrodes for High-Energy and Power-Asymmetric Supercapacitors: Superfast Room-Temperature Direct Wet Chemical Growth.

    Science.gov (United States)

    Shinde, Nanasaheb M; Xia, Qi Xun; Yun, Je Moon; Mane, Rajaram S; Kim, Kwang Ho

    2018-04-04

    Superfast (≤10 min) room-temperature (300 K) chemical synthesis of three-dimensional (3-D) polycrystalline and mesoporous bismuth(III) oxide (Bi 2 O 3 ) nanostructured negatrode (as an abbreviation of negative electrode) materials, viz., coconut shell, marigold, honey nest cross section and rose with different surface areas, charge transfer resistances, and electrochemical performances essential for energy storage, harvesting, and even catalysis devices, are directly grown onto Ni foam without and with poly(ethylene glycol), ethylene glycol, and ammonium fluoride surfactants, respectively. Smaller diffusion lengths, caused by the involvement of irregular crevices, allow electrolyte ions to infiltrate deeply, increasing the utility of inner active sites for the following electrochemical performance. A marigold 3-D Bi 2 O 3 electrode of 58 m 2 ·g -1 surface area has demonstrated a specific capacitance of 447 F·g -1 at 2 A·g -1 and chemical stability of 85% even after 5000 redox cycles at 10 A·g -1 in a 6 M KOH electrolyte solution, which were higher than those of other morphology negatrode materials. An asymmetric supercapacitor (AS) device assembled with marigold Bi 2 O 3 negatrode and manganese(II) carbonate quantum dots/nickel hydrogen-manganese(II)-carbonate (MnCO 3 QDs/NiH-Mn-CO 3 ) positrode corroborates as high as 51 Wh·kg -1 energy at 1500 W·kg -1 power and nearly 81% cycling stability even after 5000 cycles. The obtained results were comparable or superior to the values reported previously for other Bi 2 O 3 morphologies. This AS assembly glowed a red-light-emitting diode for 20 min, demonstrating the scientific and industrial credentials of the developed superfast Bi 2 O 3 nanostructured negatrodes in assembling various energy storage devices.

  18. Physical-chemical and biocatalytic properties of a proteolytic complex of the preparation "Protepsin"

    Directory of Open Access Journals (Sweden)

    L. V. Antipova

    2016-01-01

    Full Text Available Enzymatic technologies were included strongly into practical activities of the person, the volume of the world market constantly grows and is updated. However the domestic production of enzymatic preparations very lags behind world level that is in many respects connected with insufficient scientific and technical base for a wide circulation of technologies in large-scale production. At the same time there were Russian producers of enzymatic preparations from animal fabrics and bodies for processing of raw materials of an animal origin, according to forecasts, of interest in rational use of resources of an animal origin. In article data on research of properties of the enzymatic preparation "Protepsin" and an assessment of prospects of application are provided in processing of raw materials of an animal origin. The enzymatic preparation "Protepsin" made in the conditions of JSC Plant of Endocrine Enzymes (Rzhavki, Moscow region activity at action on proteins of meat shows, including the strengthened structure, has milk-clotting effect, is active in the field of pH 4,0-6,0 and temperature 20-45zs. The proteinaceous complex includes 4 fractions, 2 from which possess the general proteolytic activity. One of them shows the general proteolytic and milk-clotting activity. Enzymes differ in an amino-acid set and molecular weight. The method of a disk electrophoresis determined molecular-mass structure of "Protepsin". The preparation inactivation conditions guaranteeing its safety in the production technology of foodstuff as active proteolytic enzymes in the course of digestion can cause violations of integrity of fabrics and corresponding diseases are shown. Thus, conditions of use of a perspective proteolytic preparation in technology of a wide range of food of an animal origin are in a complex proved and picked up.

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

    International Nuclear Information System (INIS)

    Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F.; Landsberger, S.

    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

  20. Wet chemical etching of Al-doped ZnO film deposited by RF magnetron sputtering method on textured glass substrate for energy application

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ki Hwan; Nam, Sang Hun; Jung, Won Suk; Lee, Yong Min; Yang, Hee Su; Boo, Jin Hyo [Dept. of Chemistry, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-15

    The etching of glasses in aqueous hydrofluoric acid (HF) solutions is applied in many technological fields. Particularly, the textured transparent conductive oxide materials on the glass substrate etched by HF were used to improve the current density of solar cells. In this study, the textured glass substrate has been etched by solution and the Al-doped ZnO (AZO) thin films have been prepared on this textured glass substrates by RF magnetron sputtering method. After the AZO film deposition, the surface of AZO has been etched by hydrochloric acid with different concentration and etching time. Etched AZO thin films had higher haze ratio and sheet resistance than bare AZO glass. Increases in the root-mean-square surface roughness of AZO films enhanced from 53.78 to 84.46 nm the haze ratio in above 700 nm wavelength. Our process could be applicable in texturing glass and etching AZO surface to fabricate solar cell in industrial scale. We also carried out fabricating an organic solar-cell device. Energy conversion efficiency improvement of 123% was obtained with textured AZO-based solar-cell device compared with that of nontextured solar-cell device.

  1. Chemical Composition and Rheological Properties of Set Yoghurt Prepared from Skimmed Milk Treated with Horseradish Peroxidase

    Directory of Open Access Journals (Sweden)

    Yan Wen

    2012-01-01

    Full Text Available The aim of this work is to determine the impact of an enzymatic treatment on the fermentation and rheological properties of set yoghurt prepared from skimmed milk. Skimmed bovine milk was treated with horseradish peroxidase added at the level of 645 U per g of proteins in the presence (addition level of 7.8 mmol per L of milk or absence of ferulic acid as a cross-linking agent, and used to prepare set yoghurt with commercial direct vat set starter culture. The evaluation showed that the treatment of skimmed milk with horseradish peroxidase enhanced its apparent viscosity, and storage and loss moduli. The prepared yoghurt contained protein, fat and total solids at 3.49–3.59, 0.46–0.52 and 15.23–15.43 %, respectively, had titratable acidity of 0.83–0.88 %, and no significant difference in the composition was found among the yoghurt samples (p>0.05. Compared to the control yoghurt, the yoghurt prepared from the milk treated with horseradish peroxidase had a higher apparent viscosity, storage and loss moduli and flow behavior indices, especially when ferulic acid was added. Yoghurt samples from the skimmed milk treated either with horseradish peroxidase only or with the additional ferulic acid treatment had better structural reversibility, because their hysteresis loop area during rheological analysis was larger (p<0.05.

  2. 21 CFR 1308.23 - Exemption of certain chemical preparations; application.

    Science.gov (United States)

    2010-04-01

    ... special research purposes and not for general administration to a human being or other animal, if the... concentration that the packaged quantity does not present any significant potential for abuse (the type of packaging and the history of abuse of the same or similar preparations may be considered in determining the...

  3. The preparation of low electroendosmosis agarose and its physico-chemical property

    Science.gov (United States)

    Hu, Rugui; Liu, Xiaolei; Liu, Li; Zhang, Quanbin; Zhang, Hong; Niu, Xizhen

    2007-10-01

    Studies on Gelidium amansii agar fractionations were carried out in this paper. Gelidium amansii agar was fractionated on DEAE-Cellulose, and four fractions were obtained sequentially. The fractions were analyzed on physical and chemical properties, and IR and 13C-NMR spectroscopy applied for elucidating the chemical structure. Among the four fractions obtained, water fraction measured up to the standard of low EEO agarose. The sulfate content, ash content, electroendosmosis and gel strength (1%) of water fraction were 0.16%, 0.34%, 0.12 and 1 130g/cm2 respectively, similar to those of the Sigma products.

  4. COMPARISON OF PHYSICO-CHEMICAL AND SENSORY QUALITY OF SAUSAGES PREPARED FROM SPENT DUCK AND HEN MEAT

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar

    2016-06-01

    Full Text Available A study was conducted to assess the comparative quality of sausages prepared from different combination of spent duck and spent hen meats in terms of physico-chemical and sensory attributes. Sausages from 75% spent duck and 25% spent hen (T1 , 50% spent duck and 50% spent hen (T2 and 25% spent duck and 75% spent hen (T3 meats were prepared by standard methods. The quality parameter studies included pH, thiobarbituric acid (TBA, tyrosine value (TV, moisture (%, protein (%, fat (% and sensory attributes. Results revealed that pH, TV, and protein showed insignificant differences between the treatments whereas TBA, moisture and fat varied significantly (p T2 > T1.

  5. Nuclear chemical method for preparation of free carbenium ions and radiochemical investigation of reactions of these particles

    International Nuclear Information System (INIS)

    Nefedov, V.D.; Sinotova, E.N.; Toropova, M.A.

    1980-01-01

    Tritium nuclear transformation (β-decay) in the composition of the molecules of hydrocarbons, appearance of primary molecular ions and formation of free carbenium ion are the main items of nuclear-chemical method of preparation of free carbenium ions. The method permits to prepare carbenium ions present in free state, i.e. without counterion and without solvate sheath of variou nitial localization of the charge. The rate of carbenium ion generation is strictly definite and does not depend upon outer conditions. The method suggested permits to prepare carbenium ions in all phases, study their reactions with individual substances in gaseous, liquid and solid states. The study of ion-molecular reactions is carried out using radiochemical method. The analysis of the products is made using the method of gaseous radiochromatography. Development of preparation techniques of carbenium ions and their analogues, study of the reactions of these particles with different classes of compounds, investigation of the effect of different factors upon procedure of ion-molecular reactions are the main directions of the investigations

  6. Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

    Science.gov (United States)

    DeCoste, Jared B.; Peterson, Gregory W.

    2013-01-01

    Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials. PMID:24145623

  7. Room-Temperature Wet Chemical Synthesis of Au NPs/TiH2/Nanocarved Ti Self-Supported Electrocatalysts for Highly Efficient H2 Generation.

    Science.gov (United States)

    Amin, Mohammed A; Fadlallah, Sahar A; Alosaimi, Ghaida S; Ahmed, Emad M; Mostafa, Nasser Y; Roussel, Pascal; Szunerits, Sabine; Boukherroub, Rabah

    2017-09-06

    Self-supported electrocatalysts are a new class of materials exhibiting high catalytic performance for various electrochemical processes and can be directly equipped in energy conversion devices. We present here, for the first time, sparse Au NPs self-supported on etched Ti (nanocarved Ti substrate self-supported with TiH 2 ) as promising catalysts for the electrochemical generation of hydrogen (H 2 ) in KOH solutions. Cleaned, as-polished Ti substrates were etched in highly concentrated sulfuric acid solutions without and with 0.1 M NH 4 F at room temperature for 15 min. These two etching processes yielded a thin layer of TiH 2 (the corrosion product of the etching process) self-supported on nanocarved Ti substrates with different morphologies. While F - -free etching process led to formation of parallel channels (average width: 200 nm), where each channel consists of an array of rounded cavities (average width: 150 nm), etching in the presence of F - yielded Ti surface carved with nanogrooves (average width: 100 nm) in parallel orientation. Au NPs were then grown in situ (self-supported) on such etched surfaces via immersion in a standard gold solution at room temperature without using stabilizers or reducing agents, producing Au NPs/TiH 2 /nanostructured Ti catalysts. These materials were characterized by scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), grazing incidence X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS). GIXRD confirmed the formation of Au 2 Ti phase, thus referring to strong chemical interaction between the supported Au NPs and the substrate surface (also evidenced from XPS) as well as a titanium hydride phase of chemical composition TiH 2 . Electrochemical measurements in 0.1 M KOH solution revealed outstanding hydrogen evolution reaction (HER) electrocatalytic activity for our synthesized catalysts, with Au NPs/TiH 2 /nanogrooved Ti catalyst being the best one among them. It exhibited fast kinetics

  8. Surface preparation process of a uranium titanium alloy, in particular for chemical nickel plating

    International Nuclear Information System (INIS)

    Henri, A.; Lefevre, D.; Massicot, P.

    1987-01-01

    In this process the uranium alloy surface is attacked with a solution of lithium chloride and hydrochloric acid. Dissolved uranium can be recovered from the solution by an ion exchange resin. Treated alloy can be nickel plated by a chemical process [fr

  9. 78 FR 40175 - Exempt Chemical Preparations Under the Controlled Substances Act

    Science.gov (United States)

    2013-07-03

    ...Standard, Inc M-8270-04-ASL, Method 8270B-- Amber ampule: 1 mL...... 1/28/2013 Base/Neutrals Mix. Accu... CSA and its implementing regulations are designed to prevent, detect, and eliminate the diversion of... controlled substances and listed chemicals for legitimate medical, scientific, research, and industrial...

  10. Microwave-ultrasound combined reactor suitable for atmospheric sample preparation procedure of biological and chemical products

    NARCIS (Netherlands)

    Lagha, A.; Chemat, S.; Bartels, P.V.; Chemat, F.

    1999-01-01

    A compact apparatus in which a specific position can be irradiated by microwaves (MW) and ultrasound (US) simultaneously has been developed. The MW-US reactor has been designed for atmospheric pressure digestion and dissolution of biological and chemical products. The reactor can treat a range of

  11. Chemical modifiers in electrothermal atomic absorption determination of Platinum and Palladium containing preparations in blood serum

    Directory of Open Access Journals (Sweden)

    Аntonina Alemasova

    2012-11-01

    Full Text Available The biological liquids matrixes influence on the characteristic masses and repeatability of Pt and Pd electrothermal atomic absorption spectroscopy (ETAAS determination was studied. The chemical modifiers dimethylglyoxime and ascorbic acid for matrix interferences elimination and ETAAS results repeatability improvement were proposed while bioliquids ETAAS analysis, and their action mechanism was discussed.

  12. Composition and properties of nanocrystalline Zn S thin films prepared by a new chemical bath deposition route

    International Nuclear Information System (INIS)

    Sahraei, R.; Goudarzi, A.; Ahmadpoor, H.; Motedayen Aval, Gh.

    2006-01-01

    Zinc sulfide nanocrystalline thin films were prepared by a new chemical bath deposition route on soda lime glass and quartz substrates using a weak acidic bath, in which disodium salt of ethylenediaminetetraacetic acid (EDTA) acts as a complexing agent and thioacetamide acts as a source of sulfide ions. The thickness of the films varied from a few nm to 500 nm. The chemical composition of films was studied by energy-dispersive X-ray analyzer and Fourier transform infrared spectroscopy. The films are very close to Zinc sulfide stoichiometry and we did not observed any organic compounds in the impurity form in them. X-ray diffraction indicates that the film and powder formed in the same reaction bath have cubic zinc blende structure. The films have high transmittance of about 75% in the visible region. The optical band-gap energy (E g ) was determined to be 3.75 eV from the absorption spectrophotometry measurements.

  13. Preparation of ZnS microdisks using chemical bath deposition and ZnS/p-Si heterojunction solar cells

    Science.gov (United States)

    Hsiao, Y. J.; Meen, T. H.; Ji, L. W.; Tsai, J. K.; Wu, Y. S.; Huang, C. J.

    2013-10-01

    The synthesis and heterojunction solar cell properties of ZnS microdisks prepared by the chemical bath deposition method were investigated. The ZnS deposited on the p-Si blanket substrate exhibits good coverage. The lower reflectance spectra were found as the thickness of the ZnS film increased. The optical absorption spectra of the 80 °C ZnS microdisk exhibited a band-gap energy of 3.4 eV and the power conversion efficiency (PCE) of the AZO/ZnS/p-Si heterojunction solar cell with a 300 nm thick ZnS film was η=2.72%.

  14. Fabrication and characterization of chemical sensors made from nanostructured films of poly(o-ethoxyaniline) prepared with different doping acids

    Energy Technology Data Exchange (ETDEWEB)

    Brugnollo, E.D. [EMBRAPA Instrumentacao Agropecuaria, CP 741, CEP 13560-970, Sao Carlos, SP (Brazil); Instituto de Fisica de Sao Carlos, USP, CP 369, CEP 13560-970, Sao Carlos, SP (Brazil); Paterno, L.G. [Departamento de Engenharia de Sistemas Eletronicos, EPUSP, CEP 05508-900, Sao Paulo, SP (Brazil)], E-mail: paterno@lme.usp.br; Leite, F.L. [EMBRAPA Instrumentacao Agropecuaria, CP 741, CEP 13560-970, Sao Carlos, SP (Brazil); Instituto de Fisica de Sao Carlos, USP, CP 369, CEP 13560-970, Sao Carlos, SP (Brazil); Fonseca, F.J. [Departamento de Engenharia de Sistemas Eletronicos, EPUSP, CEP 05508-900, Sao Paulo, SP (Brazil); Constantino, C.J.L.; Antunes, P.A. [Departamento de Fisica, Quimica e Biologia, FCT-UNESP, CEP 19060-900, Presidente Prudente, SP (Brazil); Mattoso, L.H.C. [EMBRAPA Instrumentacao Agropecuaria, CP 741, CEP 13560-970, Sao Carlos, SP (Brazil)

    2008-03-31

    Chemical sensors made from nanostructured films of poly(o-ethoxyaniline) POEA and poly(sodium 4-styrene sulfonate) PSS are produced and used to detect and distinguish 4 chemicals in solution at 20 mM, including sucrose, NaCl, HCl, and caffeine. These substances are used in order to mimic the 4 basic tastes recognized by humans, namely sweet, salty, sour, and bitter, respectively. The sensors are produced by the deposition of POEA/PSS films at the top of interdigitated microelectrodes via the layer-by-layer technique, using POEA solutions containing different dopant acids. Besides the different characteristics of the POEA/PSS films investigated by UV-Vis and Raman spectroscopies, and by atomic force microscopy, it is observed that their electrical response to the different chemicals in liquid media is very fast, in the order of seconds, systematical, reproducible, and extremely dependent on the type of acid used for film fabrication. The responses of the as-prepared sensors are reproducible and repetitive after many cycles of operation. Furthermore, the use of an 'electronic tongue' composed by an array of these sensors and principal component analysis as pattern recognition tool allows one to reasonably distinguish test solutions according to their chemical composition.

  15. Chemical compositions of spherical titanium powders prepared by RF induction plasma

    International Nuclear Information System (INIS)

    Gu Zhongtao; Jin Yuping; Ye Gaoying

    2012-01-01

    Spherical titanium powders were prepared by RF induction plasma technology. The particle size is essentially un- changed, while the particle size distribution is relatively narrow after spheroidization processing. X-ray diffraction (XRD) random testing of the spherical titanium powders shows no structure and phase changes. The content of O, H, N and C decreases, while the content of Ti increases slightly. It indicates that spheroidization with RF plasma can enhance powder purity. (authors)

  16. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements

    OpenAIRE

    Combes, Christèle; Miao, Baoji; Bareille, Reine; Rey, Christian

    2006-01-01

    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cem...

  17. Trace organic compounds in wet atmospheric deposition: an overview

    Science.gov (United States)

    Steinheimer, T.R.; Johnson, S.M.

    1987-01-01

    An overview of the occurrence of organic compounds in wet atmospheric deposition is given. Multiplicity of sources and problems associated with source identification are discussed. Available literature is reviewed by using citations from Chemical Abstracts and Water Resources Abstracts through June 1985 and includes reports published through December 1984 that summarize current knowledge. Approaches to the chemical determination of organic compounds in precipitation are examined in addition to aspects of sampling protocols. Best methods for sample collection and preparation for instrumental analysis continue to be discussed among various investigators. Automatic wet-deposition-only devices for collection and extraction are preferred. Classes of organic compounds that have been identified in precipitation include a spectrum of compounds with differing properties of acidity or basicity, polarity, and water solubility. Those compounds that have been reported in rainfall, snowfall, and ice include hydrocarbons (both aromatic and nonaromatic), chlorinated derivatives of these hydrocarbons, carbonyl compounds (both acidic and nonacidic), and carboxylic acids and esters. Formic and acetic are the most abundant organic acids present. Cloudwater, fogwater, and mist also have been collected and analyzed for organic composition.

  18. PREPARATION AND CHARACTERIZATION OF IRON SULPHIDE THIN FILMS BY CHEMICAL BATH DEPOSITION METHOD

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-06-01

    Full Text Available FeS2 thin films have been deposited by using low cost chemical bath deposition technique. The films obtained under deposition parameters such as bath temperature (90 °C, deposition period (90 min, electrolyte concentration (0.15 M and pH of the reactive mixture (pH 2.5. The thin films were characterized using X-ray diffraction and atomic force microscopy in order to study the structural and morphological properties. The band gap energy, transition type and absorption properties were determined using UV-Vis Spectrophotometer. X-ray diffraction displayed a pattern consistent with the formation of an orthorhombic structure, with a strong (110 preferred orientation. Atomic force microscopy image showed the substrate surface is well covered with irregular grains. A direct band gap of 1.85 eV was obtained according to optical absorption studies.   Keywords: Iron sulfide, X-ray diffraction, chemical bath deposition, thin films

  19. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Science.gov (United States)

    Isik, Mehmet; Sardon, Haritz; Mecerreyes, David

    2014-01-01

    Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels. PMID:25000264

  20. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  1. Preparation of potassium tantalate niobate thin films by chemical solution deposition and their characterization

    Czech Academy of Sciences Publication Activity Database

    Buršík, Josef; Železný, Vladimír; Vaněk, Přemysl

    2005-01-01

    Roč. 25, č. 12 (2005), s. 2151-2154 ISSN 0955-2219 R&D Projects: GA ČR GA202/02/0238; GA MŠk(CZ) LN00A028; GA MŠk OC 528.001 Institutional research plan: CEZ:AV0Z40320502 Keywords : films * tantalates * chemical solution deposition Subject RIV: CA - Inorganic Chemistry Impact factor: 1.567, year: 2005

  2. Enamels in stained glass windows: Preparation, chemical composition, microstructure and causes of deterioration

    International Nuclear Information System (INIS)

    Schalm, O.; Van der Linden, V.; Frederickx, P.; Luyten, S.; Van der Snickt, G.; Caen, J.; Schryvers, D.; Janssens, K.; Cornelis, E.; Van Dyck, D.; Schreiner, M.

    2009-01-01

    Stained glass windows incorporating dark blue and purple enamel paint layers are in some cases subject to severe degradation while others from the same period survived the ravages of time. A series of dark blue, green-blue and purple enamel glass paints from the same region (Northwestern Europe) and from the same period (16-early 20th centuries) has been studied by means of a combination of microscopic X-ray fluorescence analysis, electron probe micro analysis and transmission electron microscopy with the aim of better understanding the causes of the degradation. The chemical composition of the enamels diverges from the average chemical composition of window glass. Some of the compositions appear to be unstable, for example those with a high concentration of K 2 O and a low content of CaO and PbO. In other cases, the deterioration of the paint layers was caused by the less than optimal vitrification of the enamel during the firing process. Recipes and chemical compositions indicate that glassmakers of the 16-17th century had full control over the color of the enamel glass paints they made. They mainly used three types of coloring agents, based on Co (dark blue), Mn (purple) and Cu (light-blue or green-blue) as coloring elements. Blue-purple enamel paints were obtained by mixing two different coloring agents. The coloring agent for red-purple enamel, introduced during the 19th century, was colloidal gold embedded in grains of lead glass.

  3. Preparation of SmBiO{sub 3} buffer layer on YSZ substrate by an improved chemical solution deposition route

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaolei [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Pu, Minghua, E-mail: mhpu@home.swjtu.edu.cn [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Yong [Key Laboratory of Advanced Technologies of Materials (Ministry of Education of China), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wale, Sydney, NSW 2052 (Australia)

    2016-12-15

    Highlights: • The proper conditions for SBO growth are 794 °C for 60 min in flowing Ar gas, the temperature of epitaxial growth is relatively low. • The total time by SSD technique for organic solvent removing, salts decomposition and layer growth is not up to 2 h, which are much less than that needed for traditional CSD of over 10 h. • SBO layer on YSZ prepared by SSD technique are suitable for the growth of YBCO, The results may be the usable reference for continuous preparation of SBO buffer layer on IBAD-YSZ/Ni-based alloy tapes. - Abstract: A quick route for chemical solution deposition (CSD) has been developed to prepare SmBiO{sub 3} (SBO) layers on yttria stabilized zirconia (YSZ) substrates rapidly by using of solid state decomposition (SSD) technique. The proper conditions for volatilization of lactic acid, which as solvent in precursor coated layer, and SBO growth are 115°C for 30 min and 794°C for 60 min in flowing Ar gas. The coated layers are amorphous structure of mixture oxides and quasi-crystal structure of SBO before and after growth, respectively. The total time by this quick CSD route for organic solvent volatilization, salts decomposed and layer growth is not up to 2 h, which are much less than that needed for traditional CSD of over 10 h. SBO layer is directly epitaxial growth on YSZ substrate without any lattice rotation. SBO layer prepared by this quick route as well as that by traditional route are suitable for the growth of YBCO. The superconducting transition temperature and critical current density of the coated YBCO layer on SBO/YSZ obtained by this quick route are up to 90 K and 1.66 MA/cm{sup 2}. These results may be the usable reference for continuous preparation of SBO buffer layer on IBAD-YSZ/Ni-based alloy tapes.

  4. Some physico-chemical and radiation properties of plutonium-238 metal prepared by electrochemical amalgamation

    Energy Technology Data Exchange (ETDEWEB)

    Peretrukhin, V.F. [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow 119991 (Russian Federation)], E-mail: vperet@ipc.rssi.ru; Rovny, S.I. [Production Association ' Mayak' , 31 Prospect Lenin, Ozersk, Chelyabinsk Region 456784 (Russian Federation); Maslennikov, A.G. [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow 119991 (Russian Federation); Ershov, V.V.; Chinenov, P.P.; Kapitonov, V.I.; Kuvaev, V.L. [Production Association ' Mayak' , 31 Prospect Lenin, Ozersk, Chelyabinsk Region 456784 (Russian Federation)

    2007-10-11

    Pu-238 metal was prepared by electrolytic amalgamation from Pu(III) acetate aqueous solution and by followed by the thermal decomposition of the Pu amalgam. The density, specific heat power, {gamma}-spectra, neutron flux, and corrosion kinetics in dry air at ambient temperature of the prepared {sup 238}Pu metal were measured. The neutron flux and {gamma}-spectra from {sup 238}Pu metal have been attributed to spontaneous and induced fission and to ({alpha},{alpha}'{gamma}), ({alpha},p{gamma}), and ({alpha},n{gamma}) nuclear reactions on light nuclei. The electrochemically prepared {sup 238}Pu metal was shown to generate fewer neutrons, produce less gamma radiation, and contains lower {sup 10}B, {sup 19}F, and {sup 28}Si impurities in comparison with biomedical {sup 238}PuO{sub 2}. The increase of neutron flux from the sample due to the reaction {sup 18}O({alpha},n{gamma}) {sup 21}Ne was shown to be proportional to the increase of the mass of the {sup 238}Pu metal with time due to corrosion in dry air. {sup 238}Pu metal corrosion rate maximum and average values (1.1 x 10{sup -2} and 4.7 x 10{sup -3} mg cm{sup -2} h{sup -1}, respectively) obtained in dry air were an order of magnitude higher than the rates published for {sup 239}Pu under similar experiment conditions. The difference between the {sup 239}Pu and {sup 238}Pu metal corrosion rate and mechanism is proposed to be due to the greater radiation effects and temperature on the {sup 238}Pu surface.

  5. The dosimetric properties of phosphate glass systems prepared by different chemical nanomaterials.

    Science.gov (United States)

    Abdelhalim, Mohamed Anwar K; Al-Shamrani, Bandar Mora

    2016-12-01

    The synthesis and characterization of glass systems were carried out using prepared nanocrystals injected into a glass matrix as a thermoluminescence (TL) activator using the melt-quenching method. Sample 1 was prepared as [40P 2 O 5 50BaO:2.5MgO, 2.5Na 2 O, 5TiO 2 ], sample 2 as [37.5P 2 O 5 37.5CaO:25TiO 2 ] and sample 3 as [50P 2 O 5 -50Li 2 O]. Formation of the synthesized compound was confirmed by studying the X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. An annealing procedure was carried out for 1 h at 400 °C. The glow curve position and shape shifted dramatically and linearly to the higher temperature values on increasing the heating rate. A heating rate of 30 °C/s was the most suitable for obtaining a high TL response. Samples 2 and 3 have the highest TL response, which approached the effective atomic number (Z eff ) of natural bone. The observed TL sensitivity of the prepared samples 2 and 3 is less than that of commercially available 'TLD-200 chips' and LiF:Mg,Ti (TLD-100) phosphor. Sample [37.5P 2 O 5 37.5CaO:25TiO 2 ] would be useful in personal and environmental dosimetry for measuring high doses of gamma radiation. Sample [50P 2 O 5 -50Li 2 O] is a good dosimeter, although it requires the addition of an appropriate transitional metal (activator) to overcome the problem of high fading. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Chemical stability of insulin. 1. Hydrolytic degradation during storage of pharmaceutical preparations.

    Science.gov (United States)

    Brange, J; Langkjaer, L; Havelund, S; Vølund, A

    1992-06-01

    Hydrolysis of insulin has been studied during storage of various preparations at different temperatures. Insulin deteriorates rapidly in acid solutions due to extensive deamidation at residue AsnA21. In neutral formulations deamidation takes place at residue AsnB3 at a substantially reduced rate under formation of a mixture of isoAsp and Asp derivatives. The rate of hydrolysis at B3 is independent of the strength of the preparation, and in most cases the species of insulin, but varies with storage temperature and formulation. Total transformation at B3 is considerably reduced when insulin is in the crystalline as compared to the amorphous or soluble state, indicating that formation of the rate-limiting cyclic imide decreases when the flexibility of the tertiary structure is reduced. Neutral solutions containing phenol showed reduced deamidation probably because of a stabilizing effect of phenol on the tertiary structure (alpha-helix formation) around the deamidating residue, resulting in a reduced probability for formation of the intermediate imide. The ratio of isoAsp/Asp derivative was independent of time and temperature, suggesting a pathway involving only intermediate imide formation, without any direct side-chain hydrolysis. However, increasing formation of Asp relative to isoAsp derivative was observed with decreasing flexibility of the insulin three-dimensional structure in the formulation. In certain crystalline suspensions a cleavage of the peptide bond A8-A9 was observed. Formation of this split product is species dependent: bovine greater than porcine greater than human insulin. The hydrolytic cleavage of the peptide backbone takes place only in preparations containing rhombohedral crystals in addition to free zinc ions.

  7. Wet gas sampling

    Energy Technology Data Exchange (ETDEWEB)

    Welker, T.F.

    1997-07-01

    The quality of gas has changed drastically in the past few years. Most gas is wet with hydrocarbons, water, and heavier contaminants that tend to condense if not handled properly. If a gas stream is contaminated with condensables, the sampling of that stream must be done in a manner that will ensure all of the components in the stream are introduced into the sample container as the composite. The sampling and handling of wet gas is extremely difficult under ideal conditions. There are no ideal conditions in the real world. The problems related to offshore operations and other wet gas systems, as well as the transportation of the sample, are additional problems that must be overcome if the analysis is to mean anything to the producer and gatherer. The sampling of wet gas systems is decidedly more difficult than sampling conventional dry gas systems. Wet gas systems were generally going to result in the measurement of one heating value at the inlet of the pipe and a drastic reduction in the heating value of the gas at the outlet end of the system. This is caused by the fallout or accumulation of the heavier products that, at the inlet, may be in the vapor state in the pipeline; hence, the high gravity and high BTU. But, in fact, because of pressure and temperature variances, these liquids condense and form a liquid that is actually running down the pipe as a stream or is accumulated in drips to be blown from the system. (author)

  8. Evaluation of alternative chemical additives for high-level waste vitrification feed preparation processing

    International Nuclear Information System (INIS)

    Seymour, R.G.

    1995-01-01

    During the development of the feed processing flowsheet for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), research had shown that use of formic acid (HCOOH) could accomplish several processing objectives with one chemical addition. These objectives included the decomposition of tetraphenylborate, chemical reduction of mercury, production of acceptable rheological properties in the feed slurry, and controlling the oxidation state of the glass melt pool. However, the DEPF research had not shown that some vitrification slurry feeds had a tendency to evolve hydrogen (H 2 ) and ammonia (NH 3 ) as the result of catalytic decomposition of CHOOH with noble metals (rhodium, ruthenium, palladium) in the feed. Testing conducted at Pacific Northwest Laboratory and later at the Savannah River Technical Center showed that the H 2 and NH 3 could evolve at appreciable rates and quantities. The explosive nature of H 2 and NH 3 (as ammonium nitrate) warranted significant mitigation control and redesign of both facilities. At the time the explosive gas evolution was discovered, the DWPF was already under construction and an immediate hardware fix in tandem with flowsheet changes was necessary. However, the Hanford Waste Vitrification Plant (HWVP) was in the design phase and could afford to take time to investigate flowsheet manipulations that could solve the problem, rather than a hardware fix. Thus, the HWVP began to investigate alternatives to using HCOOH in the vitrification process. This document describes the selection, evaluation criteria, and strategy used to evaluate the performance of the alternative chemical additives to CHOOH. The status of the evaluation is also discussed

  9. Preparation and characterization of activated carbon from pistachio nut shells via microwave-induced chemical activation

    International Nuclear Information System (INIS)

    Foo, K.Y.; Hameed, B.H.

    2011-01-01

    In this work, pistachio nut shell, a biomass residue abundantly available from the pistachio nut processing industries, was utilized as a feedstock for the preparation of activated carbon (PSAC) via microwave assisted KOH activation. The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. The porosity, functional and surface chemistry were featured by means of low temperature nitrogen adsorption, scanning electron microscopy and Fourier transform infrared spectroscopy. Result showed that the BET surface area, Langmuir surface area, and total pore volume of PSAC were 700.53 m 2 g -1 , 1038.78 m 2 g -1 and 0.375 m 3 g -1 , respectively. The adsorptive property of PSAC was tested using methylene blue dye as the targeted adsorbate. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 296.57 mg g -1 . The study revealed the potentiality of microwave-induced activation as a viable activation method. -- Highlights: → Pistachio nut shell activated carbon (PSAC) was prepared via microwave assisted KOH activation. → The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. → BET surface area of PSAC was 700.53 m 2 /g. → Monolayer adsorption capacity of PSAC for MB was 296.57 mg/g.

  10. Preparation and characterization of activated carbon from pistachio nut shells via microwave-induced chemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Foo, K. Y. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Hameed, B.H., E-mail: chbassim@eng.usm.my [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2011-07-15

    In this work, pistachio nut shell, a biomass residue abundantly available from the pistachio nut processing industries, was utilized as a feedstock for the preparation of activated carbon (PSAC) via microwave assisted KOH activation. The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. The porosity, functional and surface chemistry were featured by means of low temperature nitrogen adsorption, scanning electron microscopy and Fourier transform infrared spectroscopy. Result showed that the BET surface area, Langmuir surface area, and total pore volume of PSAC were 700.53 m{sup 2} g{sup -1}, 1038.78 m{sup 2} g{sup -1} and 0.375 m{sup 3} g{sup -1}, respectively. The adsorptive property of PSAC was tested using methylene blue dye as the targeted adsorbate. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 296.57 mg g{sup -1}. The study revealed the potentiality of microwave-induced activation as a viable activation method. -- Highlights: {yields} Pistachio nut shell activated carbon (PSAC) was prepared via microwave assisted KOH activation. {yields} The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. {yields} BET surface area of PSAC was 700.53 m{sup 2}/g. {yields} Monolayer adsorption capacity of PSAC for MB was 296.57 mg/g.

  11. Chemical analysis of freshly prepared and stored capsaicin solutions: implications for tussigenic challenges.

    Science.gov (United States)

    Kopec, Scott E; DeBellis, Ronald J; Irwin, Richard S

    2002-01-01

    The purpose of this study was to assess the stability of stored capsaicin solutions and the actual concentrations of prepared solutions. Capsaicin solutions ranging in concentration from 0.5 to 128 microM were mixed and analyzed using high performance liquid chromatography. Samples of varying concentrations were then stored under 4 environmental conditions: 4 degrees C and protected from light, room temperature (RT) exposed to light, RT protected from light, and -20 degrees C and protected from light. The concentrations were measured every other month for 1 year. Actual concentrations of freshly prepared solutions were on average 88.3% of predicted. For solutions stored at 4 degrees C, there was a decrease only in the lower concentrations (0.5, 1, and 2 microM) after 2 months (P=0.003). Solutions stored at RT exposed to light decreased in concentration after 6 months (P=0.020), and solutions stored at RT protected from light decreased in concentration after 4 months (P=0.026). The group stored at -20 degrees C decreased in concentration after 1 year (P=0.033). We conclude that the actual concentration of capsaicin solution is less than predicted, and solutions of 4 microM or higher concentration are stable for 1 year if stored at 4 degrees C protected from light.

  12. The structure and growth mechanism of Si nanoneedles prepared by plasma-enhanced chemical vapor deposition

    Czech Academy of Sciences Publication Activity Database

    Červenka, Jiří; Ledinský, Martin; Stuchlík, Jiří; Stuchlíková, The-Ha; Bakardjieva, Snejana; Hruška, Karel; Fejfar, Antonín; Kočka, Jan

    2010-01-01

    Roč. 21, č. 41 (2010), 415604/1-415604/7 ISSN 0957-4484 R&D Projects: GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA MŠk LC510 EU Projects: European Commission(XE) 240826 - PolySiMode Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40320502 Keywords : nanoneedles * nanowires * silicon * plasma * chemical vapor deposition * crystal structure * growth * phonon * SEM * Raman Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.644, year: 2010

  13. A non-chemically selective top-down approach towards the preparation of hierarchical TS-1 zeolites with improved oxidative desulfurization catalytic performance.

    Science.gov (United States)

    Du, Shuting; Chen, Xiaoxin; Sun, Qiming; Wang, Ning; Jia, Mingjun; Valtchev, Valentin; Yu, Jihong

    2016-02-28

    Hierarchical TS-1 zeolites with secondary macropores have been successfully prepared by using two different fluoride-containing chemical etching post-treated routes. Hierarchical TS-1 zeolites exhibited a chemical composition similar to that of the parent material and showed remarkably enhanced catalytic activity in oxidative desulfurization reaction.

  14. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  15. Textural and chemical characterization of activated carbon prepared from shell of african palm (Elaeis guineensis by chemical activation with CaCl2 and MgCl2

    Directory of Open Access Journals (Sweden)

    Sergio Acevedo

    2015-09-01

    Full Text Available Activated carbons through chemical activation of African palm shells (Elaeis guineensis with magnesium chloride and calcium chloride solutions at different concentrations were obtained. The prepared materials were characterized textural and chemically. The results show that activated carbons with higher values of surface area and pore volume are obtained when solutions with lower concentrations of the activating agent are used. The obtained activated carbons have surface areas and pore volumes with values between 10 and 501 m2 /g and 0.01 and 0.29 cm3 /g respectively. Immersion enthalpies values of solids in water were between -14.3 and -32.8 J/g and benzene between -13.9 and -38.6 J/g. Total acidity and basicity of the activated carbons had values between 23 and 262 μmol/g 123 and 1724 μmol/g respectively. pH at the point of zero charge was also determined with values between 4.08 and 9.92 for set of activated carbons . The results show that activation with CaCl2 and MgCl2 salts produce activated carbons with pores in the range of mesopores for facilitate entry of the adsorbate into the materials.

  16. Wet storage integrity update

    International Nuclear Information System (INIS)

    Bailey, W.J.; Johnson, A.B. Jr.

    1983-09-01

    This report includes information from various studies performed under the Wet Storage Task of the Spent Fuel Integrity Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. An overview of recent developments in the technology of wet storage of spent water reactor fuel is presented. Licensee Event Reports pertaining to spent fuel pools and the associated performance of spent fuel and storage components during wet storage are discussed. The current status of fuel that was examined under the CSFM Program is described. Assessments of the effect of boric acid in spent fuel pool water on the corrosion and stress corrosion cracking of stainless steel and the stress corrosion cracking of stainless steel piping containing stagnant water at spent fuel pools are discussed. A list of pertinent publications is included. 84 references, 21 figures, 11 tables

  17. Chemical mechanical polishing characteristics of ITO thin film prepared by RF magnetron sputtering

    International Nuclear Information System (INIS)

    Lee, Kang-Yeon; Choi, Gwon-Woo; Kim, Yong-Jae; Choi, Youn-Ok; Kim, Nam-Oh

    2012-01-01

    Indium-tin-oxide (ITO) thin films have attracted intensive interest because of their unique properties of good conductivity, high optical transmittance over the visible region and easy patterning ability. ITO thin films have found many applications in anti-static coatings, thermal heaters, solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), electroluminescent devices, sensors and organic light-emitting diodes (OLEDs). ITO thin films are generally fabricated by using various methods, such as spraying, chemical vapor deposition (CVD), evaporation, electron gun deposition, direct current electroplating, high frequency sputtering, and reactive sputtering. In this research, ITO films were grown on glass substrates by using a radio-frequency (RF) magnetron sputtering method. In order to achieve a high transmittance and a low resistivity, we examined the various film deposition conditions, such as substrate temperature, working pressure, annealing temperature, and deposition time. Next, in order to improve the surface quality of the ITO thin films, we performed a chemical mechanical polishing (CMP) with different process parameters and compared the electrical and the optical properties of the polished ITO thin films. The best CMP conditions with a high removal rate, low nonuniformity, low resistivity and high transmittance were as follows: platen speed, head speed, polishing time, and slurry flow rate of 30 rpm, 30 rpm, 60 sec, and 60 ml/min, respectively.

  18. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    International Nuclear Information System (INIS)

    Elen, Ken; Capon, Boris; De Dobbelaere, Christopher; Dewulf, Daan; Peys, Nick; Detavernier, Christophe; Hardy, An; Van Bael, Marlies K.

    2014-01-01

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum

  19. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Elen, Ken [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Strategisch Initiatief Materialen (SIM), SoPPoM Program (Belgium); Capon, Boris [Strategisch Initiatief Materialen (SIM), SoPPoM Programm (Belgium); Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); De Dobbelaere, Christopher [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Dewulf, Daan [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Peys, Nick [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw, Kapeldreef 75, B-3001 Heverlee (Belgium); Detavernier, Christophe [Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); Hardy, An [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Van Bael, Marlies K., E-mail: marlies.vanbael@uhasselt.be [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium)

    2014-03-31

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum.

  20. Preparation of palladium nanoparticles on alumina surface by chemical co-precipitation method and catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avvaru Praveen; Kumar, B. Prem; Kumar, A.B.V. Kiran; Huy, Bui The [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Lee, Yong-Ill, E-mail: yilee@changwon.ac.kr [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Facile synthesis of palladium nanoparticles on alumina surface. Black-Right-Pointing-Pointer The surface morphology and properties of the nanocrystalline powders were characterized. Black-Right-Pointing-Pointer The catalytic activities of palladium nanoparticles were investigated. - Abstract: The present work reports a chemical co-precipitation process to synthesize palladium (Pd) nanoparticles using alumina as a supporting material. The optimized temperature for the formation of nanocrystalline palladium was found to be 600 Degree-Sign C. The X-ray diffraction (XRD) and Raman spectroscopy were used to study the chemical nature of the Pd in alumina matrix. The surface morphology and properties of the nanocrystalline powders were examined using thermogravimetric analysis (TG-DTA), XRD, Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The calcinations in different atmospheres including in the inert medium forms the pure nano Pd{sup 0} while in the atmospheric air indicates the existence pure Pd{sup 0} along with PdO nanoparticles. The catalytic activities of the as-synthesized nanocrystalline Pd nanoparticles in the alumina matrix were investigated in Suzuki coupling, Hiyama cross-coupling, alkene and alkyne hydrogenation, and aerobic oxidation reactions.

  1. Textural and chemical characterizations of adsorbent prepared from palm shell by potassium hydroxide impregnation at different stages.

    Science.gov (United States)

    Guo, Jia; Lua, Aik Chong

    2002-10-15

    Preparation and characterization of activated carbon from palm shell, a carbonaceous agricultural solid waste, by potassium hydroxide treatment at different stages were studied. The effects of activation temperature and chemical to sample ratio on the characteristics of the activated carbon were investigated. Fixed-bed adsorption of sulfur dioxide (SO(2)) gas was carried out to evaluate the adsorptive capacity of the samples. Desorption tests were conducted to verify the occurrence of chemisorption due to some surface functional groups or of chemical reaction between SO(2) and KOH. It was found that pre-impregnation of raw palm shell was involved in replacement of some hydrogen ions with potassium ions to form cross-linked complexes, which retarded the tar formation during carbonization, resulting in a relatively high yield. Moreover, these potassium ions accelerated the reaction as catalysts during gasification of chars by carbon dioxide. For chars with mid-impregnation, potassium hydroxide acted in two ways: (i) formation of metallic potassium by dehydration and (ii) conversion into potassium carbonate. Metallic potassium intercalated to the carbon matrix accounted for pore development and potassium carbonate layer prevented the sample from over burn-off. Post-impregnation of final products modified the textural characteristics of the sample as some pore entrances were blocked by chemicals. However, potassium hydroxide enhanced the amount of SO(2) uptaken via formation of potassium sulfite.

  2. Preparation and chemical studies on Tc(III) complexes containing polyaminocarboxylic acids

    International Nuclear Information System (INIS)

    Gonzalez, R.; Kremer, C.; Chiozzone, R.; Torres, J.; Rivero, M.; Kremer, E.; Leon, A.

    1998-01-01

    Tc(III)-edta (edta = ethylenediaminetetraacetate), Tc(III)-dtpa (dtpa = diethylenetriaminepentaacetate) and Tc(III)-mebrofenin (mebrofenin = 3-bromo-2,4,6-trimethylacetanilideiminodiacetate) complexes were prepared by ligand substitution reactions on hexakis(thiourea)technetium(III) cation with the polycarboxylates. By a combination of different techniques (UV-Vis, IR and 1 H-NMR spectroscopy, Tc elemental analyses and cerimetric titrations) it was concluded that 1:1 complexes are formed with edta and dtpa while mebrofening adopts a 2:1 (ligand to metal) stoichiometry. Complementary, molecular mechanics calculations were performed to analyze the spatial arrangement of the molecules. The stability of the Tc(III) complexes was studied in aqueous solution by paper chromatography, paper electrophoresis and cyclic voltammetry. The chelates are rather stable, in particular when compared with the precursor. (orig.)

  3. Preparation, quality control and physico-chemical properties of 99mTc-BAT-AV-45

    International Nuclear Information System (INIS)

    Jiankang Zhang; Xingqin Zhou; Xiaofeng Qin

    2012-01-01

    One novel styrylpyridine derivatives(AV-45) coupled with 99m Tc complex was synthesized. 99m Tc-BAT-AV-45 was prepared by a ligand exchange reaction employing sodium glucoheptonate, and effects of the amount of ligand, stannous chloride, sodium glucoheptonate and pH value of reaction mixture on the radiolabeling yield were studied in details. Quality control was performed by thin layer chromatography and high performance liquid chromatography. Besides the stability, partition coefficient and electrophoresis of 99m Tc-BAT-AV-45 were also investigated. The results showed that the average radiolabeling yield was (95 ± 1%) and 99m Tc-BAT-AV-45 with suitable lipophilicity was stable and uncharged at physiological pH. (author)

  4. Physico-chemical characteristics of nano-organo bentonite prepared using different organo-modifiers

    Directory of Open Access Journals (Sweden)

    A.M. Motawie

    2014-09-01

    Full Text Available Different types of nano-organo bentonite (NOB were prepared from the Egyptian Bentonite (EB. EB was characterized by energy dispersive X-ray EDX. It was purified from different impurities using a conventional method via the treatment with HCl and distilled water. The modification of the clay was carried out using different types of organo-modifiers namely; hexadecyl trimethyl ammonium bromide (HTAB, 3-aminopropyltriethoxysilane (Silane, octadecylamine (ODA, and dodecylamine (DDA. The cation exchange capacity (CEC was measured for pristine bentonite after and before modification. The NB was characterized by FTIR, XRD, TEM, and TGA techniques. The obtained results indicated that variation of the interlayer space gallery was effected by the type of the penetrator used.

  5. Preparation and Performance of an Adsorption Type Gel Plugging Agent as Enhanced Oil Recovery Chemical

    Directory of Open Access Journals (Sweden)

    Xiaoping Qin

    2015-01-01

    Full Text Available A novel adsorption type gel plugging agent (ATGPA was prepared using acrylamide (AM, acrylic acid (AA, diallyl dimethyl ammonium chloride (DMDAAC, 2-acrylamido-2-methylpropanesulfonate (AMPS, formaldehyde (HCHO, resorcinol (C6H6O2, and thiocarbamide (CH4N2S as raw materials under mild conditions. ATGPA was characterized by infrared (IR spectroscopy, elemental analysis, and scanning electron microscope (SEM. It was found that ATGPA exhibited higher elastic modulus (G′ and viscous modulus (G′′ than AM/AA gel plugging agent (AAGPA under the same scanning frequency. It was also found that ATGPA had moderate temperature resistance and salt tolerance. Core plugging tests results indicated that ATGPA could achieve up to higher plugging rate (PR than AAGPA (97.2% versus 95.7% at 65°C. In addition, ATGPA possessed stronger antiscouring ability by core plugging experiments at 65°C.

  6. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements.

    Science.gov (United States)

    Combes, C; Miao, Baoji; Bareille, Reine; Rey, Christian

    2006-03-01

    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cement set and hardened within 2h at 37 degrees C in an atmosphere saturated with water and the final composition of the cement consisted mostly of aragonite. The hardened cement was microporous and showed poor mechanical properties. Cytotoxicity tests revealed excellent cytocompatibility of calcium carbonate cement compositions. Calcium carbonates with a higher solubility than the apatite formed for most of the marketed calcium phosphate cements might be of interest to increase biomedical cement resorption rates and to favour its replacement by bone tissue.

  7. Tamoxifen-loaded polymeric micelles: preparation, physico-chemical characterization and in vitro evaluation studies.

    Science.gov (United States)

    Cavallaro, Gennara; Maniscalco, Laura; Licciardi, Mariano; Giammona, Gaetano

    2004-11-20

    Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA-PEG-C(16) and PHEA-C(16)) and containing different amount of Tamoxifen, were prepared. All Tamoxifen-loaded polymeric micelles showed to increase drug water solubility. TEM studies provided evidence of the formation of supramolecular core/shell architectures containing drug, in the nanoscopic range and with spherical shape. Samples with different amount of encapsulated Tamoxifen were subjected to in vitro cytotoxic studies in order to evaluate the effect of Tamoxifen micellization on cell growth inhibition. All samples of Tamoxifen-loaded polymeric micelles showed a significantly higher antiproliferative activity in comparison with free drug, probably attributable to fluidification of cellular membranes, caused by amphiphilic copolymers, that allows a higher penetration of the drug into tumoral cells. To gain preliminary information about the potential use of prepared micelles as Tamoxifen drug delivery systems, studies evaluating drug release ability of micelle systems in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma were carried out. These studies, performed evaluating the amount of Tamoxifen that remains in solution as a function of time, showed that at pH 7.4, as well as in plasma, PHEA-C(16) polymeric micelles were able to release lower drug amounts than PHEA-PEG(5000)-C(16) ones, while at pH 5.5, the behavior difference between two kind of micelles was less pronounced.

  8. Characterization of photoluminescent europium doped yttrium oxide thin-films prepared by metallorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A.; Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M.

    1998-01-01

    Europium doped yttrium oxide, (Y 1-x Eu x ) 2 O 3 , thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y 2 O 3 , grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y 2 O 3 :Eu 3+ was observed in x-ray diffraction for deposition temperatures ≥600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra

  9. Chemical bath deposition of indium sulphide thin films: preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lokhande, C.D.; Ennaoui, A.; Patil, P.S.; Giersig, M.; Diesner, K.; Muller, M.; Tributsch, H. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Physikalische Chemie

    1999-02-26

    Indium sulphide (In{sub 2}S{sub 3}) thin films have been successfully deposited on different substrates under varying deposition conditions using chemical bath deposition technique. The deposition mechanism of In{sub 2}S{sub 3} thin films from thioacetamide deposition bath has been proposed. Films have been characterized with respect to their crystalline structure, composition, optical and electrical properties by means of X-ray diffraction, TEM, EDAX, optical absorption, TRMC (time resolved microwave conductivity) and RBS. Films on glass substrates were amorphous and on FTO (flourine doped tin oxide coated) glass substrates were polycrystalline (element of phase). The optical band gap of In{sub 2}S{sub 3} thin film was estimated to be 2.75 eV. The as-deposited films were photoactive as evidenced by TRMC studies. The presence of oxygen in the film was detected by RBS analysis. (orig.) 27 refs.

  10. Investigation of CdS/InP heterojunction prepared by chemical bath deposition

    International Nuclear Information System (INIS)

    Rakovics, V.; Horvath, Zs.J.; Horvath, Zs.E.; Barsony, I.; Frigeri, C.; Besagni, T.

    2007-01-01

    CdS thin films have been deposited on InP and glass substrates using the chemical bath deposition technique. Baths containing CdSO 4 , thiourea, and NH 3 were used. The temperature of the deposition process was 65 C and the duration of deposition varied between 20 and 160 minutes. The properties of the CdS/InP heterojunction were investigated by TEM, EDS and X-ray diffraction. TEM pictures, EDS and X-ray rocking curves indicate the formation of a β-In 2 S 3 transition layer at the InP-CdS interface, which may reduce the lattice mismatch between InP and CdS. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Biological functionalization and patterning of porous silicon prepared by Pt-assisted chemical etching

    Science.gov (United States)

    Li, Hong-Fang; Han, Huan-Mei; Wu, Ya-Guang; Xiao, Shou-Jun

    2010-04-01

    Porous silicon fabricated via Pt-assisted chemical etching of p-type Si (1 0 0) in 1:1:1 EtOH/HF/H 2O 2 solution possesses a longer durability in air and in aqueous media than anodized one, which is advantageous for biomedical applications. Its surface SiH x ( x = 1 and 2) species can react with 10-undecylenic acid completely under microwave irradiation, and subsequent derivatizations of the end carboxylic acid result in affinity capture of proteins. We applied two approaches to produce protein microarrays: photolithography and spotting. The former provides a homogeneous microarray with a very low fluorescence background, while the latter presents an inhomogeneous microarray with a high noise background.

  12. Morphology and structure of Ti-doped diamond films prepared by microwave plasma chemical vapor deposition

    Science.gov (United States)

    Liu, Xuejie; Lu, Pengfei; Wang, Hongchao; Ren, Yuan; Tan, Xin; Sun, Shiyang; Jia, Huiling

    2018-06-01

    Ti-doped diamond films were deposited through a microwave plasma chemical vapor deposition (MPCVD) system for the first time. The effects of the addition of Ti on the morphology, microstructure and quality of diamond films were systematically investigated. Secondary ion mass spectrometry results show that Ti can be added to diamond films through the MPCVD system using tetra n-butyl titanate as precursor. The spectra from X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy and the images from scanning electron microscopy of the deposited films indicate that the diamond phase clearly exists and dominates in Ti-doped diamond films. The amount of Ti added obviously influences film morphology and the preferred orientation of the crystals. Ti doping is beneficial to the second nucleation and the growth of the (1 1 0) faceted grains.

  13. Biological functionalization and patterning of porous silicon prepared by Pt-assisted chemical etching

    International Nuclear Information System (INIS)

    Li Hongfang; Han Huanmei; Wu Yaguang; Xiao Shoujun

    2010-01-01

    Porous silicon fabricated via Pt-assisted chemical etching of p-type Si (1 0 0) in 1:1:1 EtOH/HF/H 2 O 2 solution possesses a longer durability in air and in aqueous media than anodized one, which is advantageous for biomedical applications. Its surface SiHx (x = 1 and 2) species can react with 10-undecylenic acid completely under microwave irradiation, and subsequent derivatizations of the end carboxylic acid result in affinity capture of proteins. We applied two approaches to produce protein microarrays: photolithography and spotting. The former provides a homogeneous microarray with a very low fluorescence background, while the latter presents an inhomogeneous microarray with a high noise background.

  14. Study of Chemical Treatment Combined with Radiation to Prepare Biotic Elicitor for Utilization in Agriculture

    International Nuclear Information System (INIS)

    Nguyen Quoc Hien

    2010-01-01

    Chitosan was prepared from shrimp shell (alpha chitosan) and from squid pen (beta chitosan) with degree of deacetylation of about 70%. Degradation of chitosan in flake form by combined treatment with H 2 O 2 and gamma Co-60 radiation was carried out. Results showed that combined treatment was highly effective for degradation of chitosan to obtain low molecular weight of 1-2 × 10 5 . Oligochitosan was prepared by irradiation of chitosan solution of 50g/l (5%, w/v). The dose required for oligochitosan with water soluble content of more than 70% was of 32kGy and 48kGy for beta and alpha chitosan, respectively. Synergic effect of degradation of chitosan in solution with H 2 O 2 and gamma Co-60 radiation was also investigated. The dose to obtain oligochitosan was reduced from 32kGy to 4kGy for beta chitosan and from 48kGy to 8kGy for alpha chitosan. The elicitation and growth promotion effect of oligochiotsan for sugarcane and rice were investigated. Results showed that oligochitosan with water soluble content of 70-80% (Mw~5,000-10,000) exhibited the most effective elicitation and growth promotion for plant. The optimum oligochitosan concentration by spraying was of 30 and 15ppm for sugarcane and rice, respectively. The disease index of Ustilgo scitaminea and Collectotrichum falcatum on sugarcane were reduced to 44.5 and 72.3% compared to control (100%). The productivity of sugarcane was increased about 13% (8tons/ha). The disease index of Pyricularia grisea on rice was reduced to 53.0% for leaf and 34.1% for neck of bloom compared to control (100%). The productivity of rice was increased for 11-26% (0.6-1.4 tons/ha). The obtained results indicated that oligochitosan is promising to use as a biotic elicitor for plant particularly for sugarcane and rice. The procedure for production of oligochitosan elicitor by γ- irradiation method was described. (author)

  15. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  16. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reactio...

  17. The Adsorption Efficiency of Chemically Prepared Activated Carbon from Cola Nut Shells by on Methylene Blue

    Directory of Open Access Journals (Sweden)

    Julius Ndi Nsami

    2013-01-01

    Full Text Available The adsorption of methylene blue from aqueous solution onto activated carbon prepared from cola nut shell has been investigated under batch mode. The influence of major parameters governing the efficiency of the process such as, solution pH, sorbent dose, initial concentration, and contact time on the removal process was investigated. The time-dependent experimental studies showed that the adsorption quantity of methylene blue increases with initial concentration and decreasing adsorbent dosage. The equilibrium time of 180 min was observed and maximum adsorption was favoured at pH 3.5. The dye removal using 0.1 g of adsorbent was more than 90%. This dosage (0.1 g was considered as the optimum dosage to remove methylene blue from aqueous solutions. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir adsorption isotherm models. The kinetics of methylene blue solution was discussed by pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption process follows the Elovich rate kinetic model, having a correlation coefficient in the range between 0.9811 and 1.

  18. Preparation and photocatalytic activity of chemically-bonded phosphate ceramics containing TiO2

    Science.gov (United States)

    Martins, Monize Aparecida; de Lima, Bruna de Oliveira; Ferreira, Leticia Patrício; Colonetti, Emerson; Feltrin, Jucilene; De Noni, Agenor

    2017-05-01

    Titanium dioxide was incorporated into chemically-bonded phosphate ceramic for use as photocatalytic inorganic coating. The coatings obtained were applied to unglazed ceramic tiles and cured at 350 °C. The surfaces were characterized by photocatalytic activity, determined in aqueous medium, based on the degradation of methylene blue dye. The effects of the percentage of TiO2 and the thickness of the layer on the photocatalytic efficiency were evaluated. The influence of the incorporation of TiO2 on the consolidation of the phosphate matrix coating was investigated using the wear resistance test. The crystalline phases of the coatings obtained were determined by XRD. The microstructure of the surfaces was analyzed by SEM. The thermal curing treatment did not cause a phase transition from anatase to rutile. An increase in the photocatalytic activity of the coating was observed with an increase in the TiO2 content. The dye degradation indices ranged from 14.9 to 44.0%. The photocatalytic efficiency was not correlated with the thickness of the coating layer deposited. The resistance to wear decreased with an increase in the TiO2 content. Comparison with a commercial photocatalytic ceramic coating indicated that there is a range of values for the TiO2 contents which offer potential for photocatalytic applications.

  19. The preparation and cathodoluminescence of ZnS nanowires grown by chemical vapor deposition

    Science.gov (United States)

    Huang, Meng-Wen; Cheng, Yin-Wei; Pan, Ko-Ying; Chang, Chen-Chuan; Shieu, F. S.; Shih, Han C.

    2012-11-01

    Single crystal ZnS nanowires were successfully synthesized in large quantities on Si (1 0 0) substrates by simple thermal chemical vapor deposition without using any catalyst. The morphology, composition, and crystal structure were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and cathodoluminescence (CL) spectroscopy. SEM observations show that the nanowires have diameters about 20-50 nm and lengths up to several tens of micrometers. XRD and TEM results confirmed that the nanowires exhibited both wurtzite and zinc blende structures with growth directions aligned along [0 0 0 2] and [1 1 1], respectively. The CL spectrum revealed emission bands in the UV and blue regions. The blue emissions at 449 and ˜581 nm were attributed to surface states and impurity-related defects of the nanowires, respectively. The perfect crystal structure of the nanowires indicates their potential applications in nanotechnology and in the fabrication of nanodevices.

  20. Comparison of selected physico-chemical properties of calcium alginate films prepared by two different methods.

    Science.gov (United States)

    Crossingham, Yazmin J; Kerr, Philip G; Kennedy, Ross A

    2014-10-01

    Sodium alginate (SA) is a naturally occurring, non-toxic, polysaccharide that is able to form gels after exposure to calcium. These gels have been used in food and biomedical industries. This is the first direct comparison of two different methods of calcium alginate film production, namely interfacial gelation (IFG) and dry cast gelation (DCG). IFG films were significantly thicker than DCG films, and were more extensively rehydrated in water and 0.1M HCl than the DCG films. During rehydration in 0.1M HCl almost all calcium ions were lost. Under scanning electron microscopy, IFG films appeared less dense than DCG films. IFG films were mechanically weaker than DCG films, and both types of film were weaker after rehydration in 0.1M HCl compared with deionized water. Permeation of theophylline (TPL) was evaluated in-vitro; the diffusion coefficient (D) of the TPL was almost 90 times lower in DCG films than IFG films when both were rehydrated in water. Although the 0.1M HCl rendered both gels more permeable to TPL, D of TPL was still about five times lower in DCG compared to IFG films. The evaluation of selected physico-chemical properties of films is important, since this information may inform the choice of gelation technique used to produce calcium alginate coatings on pharmaceutical products. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Preparation of high surface area and high conductivity polyaniline nanoparticles using chemical oxidation polymerization technique

    Science.gov (United States)

    Budi, S.; Yusmaniar; Juliana, A.; Cahyana, U.; Purwanto, A.; Imaduddin, A.; Handoko, E.

    2018-03-01

    In this work, polyaniline nanoparticles were synthesized using a chemical oxidation polymerization technique. The ammonium peroxydisulfate (APS)/aniline ratio, APS dropping time, and polymerization temperature were optimized to increase the surface area and conductivity of the polyaniline.The Fourier-transform infrared (FTIR) spectrum confirmed the formation of emeraldine salt polyaniline. X-ray diffraction (XRD) patterns indicated that amorphous and crystalline phases of the polyaniline were formed with crystallinity less than 40%. Scanning electron microscope (SEM) micrographs showed that the finest nanoparticles with uniform size distribution were obtained at the polymerization temperature of 0°C. A surface area analyzer (SAA) showed that the highest Brunauer-Emmett-Teller surface area (SBET ) of 42.14 m2/gwas obtained from an APS/aniline ratio of 0.75 with a dropping time of 0 s at a polymerization temperature of 0°C. A four-point probe measurement conducted at 75–300K indicated relatively high conductivity of the semiconductor characteristic of the polyaniline.

  2. Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

    International Nuclear Information System (INIS)

    Mishra, A.K.; Das, D.

    2010-01-01

    Zn 1-x Fe x O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by 57 Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe 3+ . Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

  3. Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, A.K. [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India); Das, D., E-mail: ddas@alpha.iuc.res.in [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India)

    2010-07-25

    Zn{sub 1-x}Fe{sub x}O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by {sup 57}Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe{sup 3+}. Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

  4. The challenge of preparation for a chemical, biological, radiological or nuclear terrorist attack

    Directory of Open Access Journals (Sweden)

    Alexander David

    2006-01-01

    Full Text Available Terrorism is not a new phenomenon, but, in the contemporary scene, it has established itself in a manner which commands the most serious attention of the authorities. Until relatively recently, the major threat has been through the medium of conventional weaponry and explosives. Their obvious convenience of use and accessibility guarantees that such methods will continue to represent a serious threat. However, over the last few years, terrorists have displayed an enthusiasm for higher levels of carnage, destruction and publicity. This trend leads inexorably to the conclusion that chemical, biological, radiological and nuclear (CBRN methods will be pursued by terrorist organisations, particularly those which are well organised, are based on immutable ideological principles, and have significant financial backing. Whilst it is important that the authorities and the general public do not risk over-reacting to such a threat (otherwise, they will do the work of the terrorists for them, it would be equally ill-advised to seek comfort in denial. The reality of a CBRN event has to be accepted and, as a consequence, the authorities need to consider (and take seriously how individuals and the community are likely to react thereto and to identify (and rehearse in a realistic climate what steps would need to be taken to ameliorate the effects of such an event.

  5. Structural and optical properties of Ni-doped CdS thin films prepared by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Premarani, R. [Arumugam Pillai SeethaiAmmal College, Thiruppattur-630211 (India); Saravanakumar, S., E-mail: sarophy84@gmail.com; Chandramohan, R. [SreeSevuganAnnamalai College, Devakottai-630303 (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of)

    2015-06-24

    The structural and optical behavior of undoped Cadmiun Sulphide (CdS) and Ni-doped CdS thinfilms prepared by Chemical Bath Deposition (CBD) technique is reported. The crystallite sizes of the thinfilms have been characterized by X-ray diffraction pattern (XRD). The particle sizes increase with the increase of Ni content in the CdS thinfilms. Scanning Electron Microscope (SEM) results indicated that CdS thinfilms is made up of aggregate of spherical-like particles. The composition was estimated by Energy Dispersive Analysis of X-ray (EDX) and reported. Spectroscopic studies revealed considerable improvement in transmission and the band gap of the films changes with addition of Ni dopant that is associated with variation in crystallite sizes in the nano regime.

  6. Anisotropic electrical conduction and reduction in dangling-bond density for polycrystalline Si films prepared by catalytic chemical vapor deposition

    Science.gov (United States)

    Niikura, Chisato; Masuda, Atsushi; Matsumura, Hideki

    1999-07-01

    Polycrystalline Si (poly-Si) films with high crystalline fraction and low dangling-bond density were prepared by catalytic chemical vapor deposition (Cat-CVD), often called hot-wire CVD. Directional anisotropy in electrical conduction, probably due to structural anisotropy, was observed for Cat-CVD poly-Si films. A novel method to separately characterize both crystalline and amorphous phases in poly-Si films using anisotropic electrical conduction was proposed. On the basis of results obtained by the proposed method and electron spin resonance measurements, reduction in dangling-bond density for Cat-CVD poly-Si films was achieved using the condition to make the quality of the included amorphous phase high. The properties of Cat-CVD poly-Si films are found to be promising in solar-cell applications.

  7. Improvement in fatigue property for a PZT ferroelectric film device with SRO electrode film prepared by chemical solution deposition

    International Nuclear Information System (INIS)

    Miyazaki, H.; Miwa, Y.; Suzuki, H.

    2007-01-01

    PZT films with (1 0 0) and (1 1 0) orientation were prepared by spin coating using the chemical solution deposition (CSD) method on an SRO/Si or a Pt/Ti/SiO 2 /Si substrate. The remnant polarization and the saturation polarization of the PZT/SRO/Si film were 21 and 35 μC/cm 2 , and those of the PZT/Pt/Ti/SiO 2 /Si film were 20 and 31 μC/cm 2 . The remnant polarization of the PZT/SRO/Si film maintained more than 10 8 switching cycles, and the fatigue property was observed for the PZT film fabricated on the Pt/Ti/SiO 2 /Si electrode

  8. In situ chemical oxidative polymerization preparation of poly(3,4-ethylenedioxythiophene)/graphene nanocomposites with enhanced thermoelectric performance.

    Science.gov (United States)

    Xu, Kongli; Chen, Guangming; Qiu, Dong

    2015-05-01

    Three different in situ chemical oxidative polymerization routes, that is, (A) spin-coating and subsequent liquid layer polymerization, (B) spin-coating followed by vapor phase polymerization, and (C) in situ polymerization and then post-treatment by immersion in ethylene glycol (EG), have been developed to achieve poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (PEDOT/rGO) nanocomposites. As demonstrated by scanning electron microscopic and energy-dispersive X-ray spectroscopic techniques, PEDOT has been successfully coated on the surface of the rGO nanosheets by each of the three preparation routes. Importantly, all of the nanocomposites display a greatly enhanced thermoelectric performance (power factors) relative to those of the corresponding neat PEDOT. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Passivated graphene transistors fabricated on a millimeter-sized single-crystal graphene film prepared with chemical vapor deposition

    International Nuclear Information System (INIS)

    Lin, Meng-Yu; Lee, Si-Chen; Lin, Shih-Yen; Wang, Cheng-Hung; Chang, Shu-Wei

    2015-01-01

    In this work, we first investigate the effects of partial pressures and flow rates of precursors on the single-crystal graphene growth using chemical vapor depositions on copper foils. These factors are shown to be critical to the growth rate, seeding density and size of graphene single crystals. The prepared graphene films in millimeter sizes are then bubbling transferred to silicon-dioxide/silicon substrates for high-mobility graphene transistor fabrications. After high-temperature annealing and hexamethyldisilazane passivation, the water attachment is removed from the graphene channel. The elimination of uncontrolled doping and enhancement of carrier mobility accompanied by these procedures indicate that they are promising for fabrications of graphene transistors. (paper)

  10. Chemical state and phase structure of (TaNbTiW)N films prepared by combined magnetron sputtering and PBII

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xingguo [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze [National Key Laboratory of Materials Behavior and Evaluation in Space Environment, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [National Key Laboratory of Science and Technology on Precision Hot Processing of Metals Harbin Institute of Technology, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin, E-mail: maxin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, 150001 (China)

    2013-09-01

    (TaNbTiW)N films with thickness of ∼1000 nm are prepared on titanium alloy substrate by combined magnetron sputtering deposition and nitrogen plasma based ion implantation (N-PBII). Chemical state of the elements and phase structure of the films are investigated using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The bonds of Ta-N, Nb-N, Ti-N-O and Ta-O are detected in the (TaNbTiW)N films, however both W-N and W-O are not found. The initial alloy film has a BCC structure, while the films with N-PBII treatment are composed of BCC and FCC structures. The hardness and elastic modulus of the films can be improved by increasing nitrogen implantation dose and reach maximum values of 9.0 GPa and 154.1 GPa, respectively.

  11. Inorganic-organic hybrid polyoxometalate containing supramolecular helical chains: Preparation, characterization and application in chemically bulk-modified electrode

    International Nuclear Information System (INIS)

    Han Zhangang; Zhao Yulong; Peng Jun; Liu Qun; Wang Enbo

    2005-01-01

    An inorganic-organic hybrid polyoxometalate (POM) (Hbpy) 4 [SiMo 12 O 40 ] (1) (bpy = 2,4-bipyridine), has been prepared and characterized. X-ray diffraction study reveals that compound 1 contains interesting organic double helical chains. The hybrid nanoparticles was used as a solid bulkmodifier to fabricate a three-dimensional chemically modified carbon paste electrode (1-CPE) by direct mixing. The electrochemical behavior and electrocatalysis of 1-CPE has been studied in detail. The results indicate that 1-CPE has a good electrocatalytic activity toward the reduction of nitrite in 1 M H 2 SO 4 aqueous solution. 1-CPE shows remarkable stability that can be ascribed to the interactions existed between POM anions and organic double helical bpy chains, which are very important for practical applications in electrode modification

  12. Preparation of rutile TiO(2) coating by thermal chemical vapor deposition for anticoking applications.

    Science.gov (United States)

    Tang, Shiyun; Wang, Jianli; Zhu, Quan; Chen, Yaoqiang; Li, Xiangyuan

    2014-10-08

    To inhibit the metal catalytic coking and improve the oxidation resistance of TiN coating, rutile TiO2 coating has been directly designed as an efficient anticoking coating for n-hexane pyrolysis. TiO2 coatings were prepared on the inner surface of SS304 tubes by a thermal CVD method under varied temperatures from 650 to 900 °C. The rutile TiO2 coating was obtained by annealing the as-deposited TiO2 coating, which is an alternative route for the deposition of rutile TiO2 coating. The morphology, elemental and phase composition of TiO2 coatings were characterized by SEM, EDX and XRD, respectively. The results show that deposition temperature of TiO2 coatings has a strong effect on the morphology and thickness of as-deposited TiO2 coatings. Fe, Cr and Ni at.% of the substrate gradually changes to 0 when the temperature is increased to 800 °C. The thickness of TiO2 coating is more than 6 μm and uniform by metalloscopy, and the films have a nonstoichiometric composition of Ti3O8 when the deposition temperature is above 800 °C. The anticoking tests show that the TiO2 coating at a deposition temperature of 800 °C is sufficiently thick to cover the cracks and gaps on the surface of blank substrate and cut off the catalytic coke growth effect of the metal substrate. The anticoking ratio of TiO2 coating corresponding to each 5 cm segments is above 65% and the average anticoking ratio of TiO2 coating is up to 76%. Thus, the TiO2 coating can provide a very good protective layer to prevent the substrate from severe coking efficiently.

  13. Preparation and physico-chemical study of nitroxide radicals. Isotopic marking with carbon 13 and deuterium

    International Nuclear Information System (INIS)

    Chapelet-Letourneux, G.

    1969-01-01

    N-t-butyl-N-phenyl nitroxide is obtained by: a) action of t-butyl-magnesium chloride on nitrobenzene, or of phenyl-magnesium bromide on nitro-t-butane, b) oxidation of N-t-butyl-N-phenylhydroxylamine, c) oxidation of N-t-butylaniline. In these latter two cases, it has been possible to isolate the pure radical and to study it using UV, IR and EPR. It decomposes to give N-t-butylaniline and the N-oxide of N-t-butyl-p-quinon-imine. The action of peracids such as p-nitro-perbenzoic or m-chloro-perbenzoic acids on amines or hydroxylamines leads to the formation of stable or unstable nitroxide radicals easily observable by EPR. Finally, with a view to obtaining definite values for the coupling between the free electron of a nitroxide and carbon 13, the preparation of such radicals marked with 13 C in the α or β position of the nitroxide function has been carried out. The coupling with an α carbon 13 is negative and does not appear to vary with the spin density on the nitrogen. The interaction with the p nuclei of the nitrogen depends on the nature of the substituents: the two benzyl protons have a hyperfine splitting a H which is always less than that of the ethyl. On the other hand, the 13 C coupling is greater in the first case. The usually adopted conformations for the compounds having the carbonyl group cannot account for the observed values of the β couplings. (author) [fr

  14. Chemical modification of magnetite nanoparticles and preparation of acrylic-base magnetic nanocomposite particles via miniemulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mahdieh, Athar; Mahdavian, Ali Reza, E-mail: a.mahdavian@ippi.ac.ir; Salehi-Mobarakeh, Hamid

    2017-03-15

    Nowadays, magnetic nanocomposite particles have attracted many interests because of their versatile applications. A new method for chemical modification of Fe{sub 3}O{sub 4} nanoparticles with polymerizable groups is presented here. After synthesis of Fe{sub 3}O{sub 4} nanoparticles by co-precipitation method, they were modified sequentially with 3-aminopropyl triethoxysilane (APTES), acryloyl chloride (AC) and benzoyl chloride (BC) and all were characterized by FTIR, XRD, SEM and TGA analyses. Then the modified magnetite nanoparticles with unsaturated acrylic groups were copolymerized with methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) through miniemulsion polymerization. Although several reports exist on preparation of magnetite-base polymer particles, but the efficiency of magnetite encapsulationwith reasonable content and obtaining final stable latexes with limited aggregation ofFe{sub 3}O{sub 4} are still important issues. These were considered here by controlling reaction parameters. Hence, a seriesofmagneticnanocomposites latex particlescontaining different amounts of Fe{sub 3}O{sub 4} nanoparticles (0–10 wt%) were prepared with core-shell morphology and diameter below 200 nm and were characterized by FT-IR, DSC and TGA analyses. Their morphology and size distribution were studied by SEM, TEM and DLS analyses too. Magnetic properties of all products were also measuredby VSM analysis and the results revealed almost superparamagnetic properties for the obtained nanocomposite particles. - Highlights: • Chemical modification of magnetite nanoparticles. • Encapsulation of modified magnetite with acrylic copolymer. • Superparamagnetic Fe3O4/polyacrylic nanocomposite particles.

  15. The preparation and cathodoluminescence of ZnS nanowires grown by chemical vapor deposition

    International Nuclear Information System (INIS)

    Huang, Meng-Wen; Cheng, Yin-Wei; Pan, Ko-Ying; Chang, Chen-Chuan; Shieu, F.S.; Shih, Han C.

    2012-01-01

    Highlights: ► ZnS nanowires have been achieved by thermal evaporation. ► The nanowires were 20–50 nm in diameter and up to tens of nanometers in length. ► Single-crystalline wurtzite and sphalerite ZnS phase are coexist in the nanowires. ► The ZnS nanowires showed almost identical blue luminescence at room temperature. ► ZnS nanowires may be appropriate for use in UV/blue LED phosphor materials. - Abstract: Single crystal ZnS nanowires were successfully synthesized in large quantities on Si (1 0 0) substrates by simple thermal chemical vapor deposition without using any catalyst. The morphology, composition, and crystal structure were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and cathodoluminescence (CL) spectroscopy. SEM observations show that the nanowires have diameters about 20–50 nm and lengths up to several tens of micrometers. XRD and TEM results confirmed that the nanowires exhibited both wurtzite and zinc blende structures with growth directions aligned along [0 0 0 2] and [1 1 1], respectively. The CL spectrum revealed emission bands in the UV and blue regions. The blue emissions at 449 and ∼581 nm were attributed to surface states and impurity-related defects of the nanowires, respectively. The perfect crystal structure of the nanowires indicates their potential applications in nanotechnology and in the fabrication of nanodevices.

  16. Effect of protic solvents on CdS thin films prepared by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Pin-Chuan, E-mail: pcyao@mail.dyu.edu.tw; Chen, Chun-Yu

    2015-03-31

    In this study, cadmium sulfide (CdS) thin films are grown on glass substrates by chemical bath deposition (CBD) in an aqueous bath containing 10–20 vol.% alcohol. The roles of ethanol as a protic solvent that substantially improves the quality of films are explored extensively. The deposited films in an alcohol bath are found to be more compact and smoother with smaller CdS grains. The X-ray diffractograms of the samples confirm that all films were polycrystalline with mixed wurtzite (hexagonal) and zinkblende (cubic) phases. Raman spectra indicate that, for a film deposited in an alcohol bath, the position of 1LO is closer to the value for single crystal CdS, indicating that these films have a high degree of crystallinity. The as-deposited CdS thin films in a 10 vol.% alcohol bath were found to have the highest visible transmittance of 81.9%. XPS analysis reveals a stronger signal of C1s for samples deposited in the alcohol baths, indicating that there are more carbonaceous residues on the films with protic solvent than on the films with water. A higher XPS S/Cd atomic ratio for films deposited in an alcohol bath indicates that undesirable surface reactions (leading to sulfur containing compounds other than CdS) occur less frequently over the substrates. - Highlights: • Study of CBD-CdS films grown in an alcohol-containing aqueous bath is reported. • The deposited films in an alcohol bath are more compact with smaller CdS grains. • Raman spectra show that in an alcohol bath, the CdS film has a better crystallinity. • XPS reveals more carbon residues remain on the films deposited using alcohol bath. • In an alcohol bath, the undesirable surface reactions with Cd ions were hindered.

  17. Preparation of Nb3Ge films by chemical transport reaction and their critical properties

    International Nuclear Information System (INIS)

    Oya, G.; Saur, E.J.

    1979-01-01

    Niobium-germanium films have been deposited on sapphire substrates at 900 0 C by a chemical transport reaction method. The highest superconducting transition onset temperature T/sub C,on/ of 22.4K is observed for a nearly stoichiometric Nb 3 Ge film with the A15-type structure (thickness approx.93.5 μm). Lattice constants for the Nb 3 Ge phase formed in the Nb-Ge films with both T/sub C,on/ above 22 K and T/sub C,midpoint/ above 21 K are found to extend from 5.143 to 5.153 A. Deposition rates for the obtained films are in the range of 2-10 μm/min. Critical current densities for the Nb 3 Ge film with the highest T/sub C,on/ value are observed to be relatively low (approx.10 3 A/cm 2 at 19 K at self-field). This is due to the coarse grain structure of the film or the low density of effectual pinning centers in the film. Field variations of the pinning forces operating in this film in magnetic fields both parallel to the film surface and perpendicular to the film surface are found to follow closely b/sup 1/2/ (1-b) 2 , to which the pinning force for flux pinning at the surface of normal regions, such as grain boundaries, film surfaces, etc., is proportional, and where b is the reduced magnetic induction (B/B/sub C2/). A small increase in J/sub C/ at low fields is caused by the presence of a small amount of the Nb 5 Ge 3 phase in a Nb 3 Ge film, and seems attributable to additional flux pinning on Nb 5 Ge 3 -phase particles in the film

  18. Wetting of flat gradient surfaces.

    Science.gov (United States)

    Bormashenko, Edward

    2018-04-01

    Gradient, chemically modified, flat surfaces enable directed transport of droplets. Calculation of apparent contact angles inherent for gradient surfaces is challenging even for atomically flat ones. Wetting of gradient, flat solid surfaces is treated within the variational approach, under which the contact line is free to move along the substrate. Transversality conditions of the variational problem give rise to the generalized Young equation valid for gradient solid surfaces. The apparent (equilibrium) contact angle of a droplet, placed on a gradient surface depends on the radius of the contact line and the values of derivatives of interfacial tensions. The linear approximation of the problem is considered. It is demonstrated that the contact angle hysteresis is inevitable on gradient surfaces. Electrowetting of gradient surfaces is discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Characterization of mesoporous carbon prepared from date stems by H{sub 3}PO{sub 4} chemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Hadoun, H., E-mail: hhadoun@hotmail.com [Nuclear Research Center, 2 Bd Frantz Fanon, Algiers (Algeria); Laboratory of Reaction Genius, Mechanical and Processes Genius Faculty, University of Sciences and Technology Houari – Boumediene, BP n°32, El alia, bab ezzouar, 16111 Algiers (Algeria); Sadaoui, Z. [Laboratory of Reaction Genius, Mechanical and Processes Genius Faculty, University of Sciences and Technology Houari – Boumediene, BP n°32, El alia, bab ezzouar, 16111 Algiers (Algeria); Souami, N.; Sahel, D.; Toumert, I. [Nuclear Research Center, 2 Bd Frantz Fanon, Algiers (Algeria)

    2013-09-01

    The present work was focused on the determination of texture, morphology, crystanillity and oxygenated surface groups characteristics of an activated carbon prepared from date stems. Chemical activation of this precursor at different temperatures (450, 550 and 650 °C) was adopted using phosphoric acid as dehydrating agent at (2/1) impregnation ratio. Fourier transform infrared spectroscopy study was carried out to identify surface groups in date stems activated carbons. The microscopic structure was examined by nitrogen adsorption at 77 K. The interlayer spacing (d{sub 200} and d{sub 100}), stack height (L{sub c}), stack width (L{sub a}) and effective dimension L of the turbostratic crystallites (microcrystallite) in the date stems activated carbons were estimated from X-ray diffraction data (XRD). Results yielded a surface area, S{sub BET}, and total pore volume of 682, 1455, 1319 m{sup 2}/g and 0,343, 1,045 and 0.735 cm{sup 3}/g, for the carbon prepared at 450, 550 and 650 °C, respectively. Scanning electron microscopy exhibits a highly developed porosity which is in good agreement with the porous texture derived from gas adsorption data and these results confirm that the activated carbon is dominated by network of slit-shaped mesopores morphology and in some cases by varied micropores morphologies.

  20. On the structure and surface chemical composition of indium-tin oxide films prepared by long-throw magnetron sputtering

    International Nuclear Information System (INIS)

    Chuang, M.J.; Huang, H.F.; Wen, C.H.; Chu, A.K.

    2010-01-01

    Structures and surface chemical composition of indium tin oxide (ITO) thin films prepared by long-throw radio-frequency magnetron sputtering technique have been investigated. The ITO films were deposited on glass substrates using a 20 cm target-to-substrate distance in a pure argon sputtering environment. X-ray diffraction results showed that an increase in substrate temperature resulted in ITO structure evolution from amorphous to polycrystalline. Field-emission scanning electron microscopy micrographs suggested that the ITO films were free of bombardment of energetic particles since the microstructures of the films exhibited a smaller grain size and no sub-grain boundary could be observed. The surface composition of the ITO films was characterized by X-ray photoelectron spectroscopy (XPS). Oxygen atoms in both amorphous and crystalline ITO structures were observed from O 1 s XPS spectra. However, the peak of the oxygen atoms in amorphous ITO phase could only be found in samples prepared at low substrate temperatures. Its relative peak area decreased drastically when substrate temperatures were larger than 200 o C. In addition, a composition analysis from the XPS results revealed that the films deposited at low substrate temperatures contained high concentration of oxygen at the film surfaces. The oxygen-rich surfaces can be attributed to hydrolysis reactions of indium oxides, especially when large amount of the amorphous ITO were developed near the film surfaces.

  1. Evaluation of the effect of conventionally prepared swarna makshika bhasma on different bio-chemical parameters in experimental animals

    Directory of Open Access Journals (Sweden)

    Sudhaldev Mohapatra

    2011-01-01

    Full Text Available Swarna makshika (chalcopyrite bhasma (SMB has been used for different therapeutic purposes since long in Ayurveda. The present study is conducted to evaluate the effect of conventionally prepared SMB on different bio-chemical parameters in experimental animals, for providing scientific data base for its logical use in clinical practice. The genuine SMB was prepared by following classical techniques of shodhana and marana most commonly used by different Ayurvedic drug manufacturers. Shodhana was done by roasting raw swarna makshika with lemon juice for three days and marana was performed by 11 putas . The experimental animals (rats were divided into two groups. SMB mixed with diluted honey was administered orally in therapeutic dose to Group SMB and diluted honey only was administered to vehicle control Group, for 30 days. The blood samples were collected twice, after 15 days and after 30 days of drug administration and different biochemical investigations were done. Biochemical parameters were chosen based on references from Ayurvedic classics and contemporary medicine. It was observed that Hb% was found significantly increased and LDL and VLDL were found significantly decreased in Group SMB when compared with vehicle control group. This experimental data will help the clinician for the logical use of SMB in different disease conditions with findings like low Hb% and high LDL, VLDL levels.

  2. Physico-chemical properties of the new generation IV iron preparations ferumoxytol, iron isomaltoside 1000 and ferric carboxymaltose.

    Science.gov (United States)

    Neiser, Susann; Rentsch, Daniel; Dippon, Urs; Kappler, Andreas; Weidler, Peter G; Göttlicher, Jörg; Steininger, Ralph; Wilhelm, Maria; Braitsch, Michaela; Funk, Felix; Philipp, Erik; Burckhardt, Susanna

    2015-08-01

    The advantage of the new generation IV iron preparations ferric carboxymaltose (FCM), ferumoxytol (FMX), and iron isomaltoside 1000 (IIM) is that they can be administered in relatively high doses in a short period of time. We investigated the physico-chemical properties of these preparations and compared them with those of the older preparations iron sucrose (IS), sodium ferric gluconate (SFG), and low molecular weight iron dextran (LMWID). Mössbauer spectroscopy, X-ray diffraction, and Fe K-edge X-ray absorption near edge structure spectroscopy indicated akaganeite structures (β-FeOOH) for the cores of FCM, IIM and IS, and a maghemite (γ-Fe2O3) structure for that of FMX. Nuclear magnetic resonance studies confirmed the structure of the carbohydrate of FMX as a reduced, carboxymethylated, low molecular weight dextran, and that of IIM as a reduced Dextran 1000. Polarography yielded significantly different fingerprints of the investigated compounds. Reductive degradation kinetics of FMX was faster than that of FCM and IIM, which is in contrast to the high stability of FMX towards acid degradation. The labile iron content, i.e. the amount of iron that is only weakly bound in the polynuclear iron core, was assessed by a qualitative test that confirmed decreasing labile iron contents in the order SFG ≈ IS > LMWID ≥ FMX ≈ IIM ≈ FCM. The presented data are a step forward in the characterization of these non-biological complex drugs, which is a prerequisite to understand their cellular uptake mechanisms and the relationship between the structure and physiological safety as well as efficacy of these complexes.

  3. Effect of gamma irradiation on the microbial load, Chemical and sensory properties of borak : Prepared chilled meals

    International Nuclear Information System (INIS)

    Al-Bachir, M.

    2007-01-01

    Locally prepared meals, borak, were treated with 0, 2, 4 and 6 kGy doses of gamma irradiation. Treated and untreated borak were kept in a refrigerator (1-4 Centigrade). Microbiological and chemical analyses were performed on each treated sample immediately after processing, and weekly throughout storage period which lasted for 6 weeks. Sensory evaluation and proximate analysis were done within one week after irradiation. Results of the proximate analysis of borak showed that irradiation doses did not have a significant effect on moisture, protein and fat content of borak. Gamma irradiation decreased the total counts of mesophilic aerobic bacteria, total coliform and yeat and increased the shelf-life of borak. The radiation doses required to reduce the microorganisms load one log cycle (D 1 0) in borak were 456 and 51- Gy for the Salmonella spp and E. coli, respectively: The three chemical parameters, total acidity, lipid peroxide and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limits for up to 1, 3 and 6 weeks at 1-4 Centigrade for samples treated with 2, 4 and 6 kGy, respectively. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  4. Synthesis and characterization of graphene layers prepared by low-pressure chemical vapor deposition using triphenylphosphine as precursor

    Energy Technology Data Exchange (ETDEWEB)

    Mastrapa, G.C.; Maia da Costa, M.E.H. Maia [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Larrude, D.G., E-mail: dunigl@vdg.fis.puc-rio.br [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Freire, F.L. [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Brazilian Center for Physical Research, 22290-180, Rio de Janeiro, RJ (Brazil)

    2015-09-15

    The synthesis of a single-layer graphene using a low-pressure Chemical Vapor Deposition (CVD) system with triphenylphosphine as precursor is reported. The amount of triphenylphosphine used as precursor was in the range of 10–40 mg. Raman spectroscopy was employed to analyze samples prepared with 10 mg of the precursor, and these spectra were found typical of graphene. The Raman measurements indicate that the progressive degradation of graphene occurs as the amount of triphenylphosphine increases. X-ray photoelectron spectroscopy measurements were performed to investigate the different chemical environments involving carbon and phosphorous atoms. Scanning electron microscopy and transmission electron microscopy were also employed and the results reveal the formation of dispersed nanostructures on top of the graphene layer, In addition, the number of these nanostructures is directly related to the amount of precursor used for sample growth. - Highlights: • We grow graphene using the solid precursor triphenylphosphine. • Raman analysis confirms the presence of monolayer graphene. • SEM images show the presence of small dark areas dispersed on the graphene surface. • Raman I{sub D}/I{sub G} ratio increases in the dark region of the graphene surface.

  5. Effect of Gamma Radiation on Microbial load, Chemical and Sensory Properties of Sheesh Tawoq, Prepared Chilled Meal

    International Nuclear Information System (INIS)

    Al-Bachir, M.

    2011-01-01

    Locally prepared meal Sheesh Tawoq was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated Sheesh Tawoq were kept in a refrigerator (1 and 4 mC). Microbiological, chemical and sensory characteristics of Sheesh Tawoq were evaluated at 0, 4, 8, 12, 16 and 20th week of storage. The results indicate that 4 and 6 kGy doses of gamma irradiation decreased the total counts of mesophilic aerobic bacteria, total coliform and yeast. Thus the microbiological shelf-life of Sheesh Tawoq was significantly extended from 12 weeks (control) to more than 20 weeks (samples treated with 4 or 6 kGy). Irradiation doses did not have a significant effect on the major constituents of Sheesh Tawoq (moisture, protein and fats). The radiation doses required to reduce the microorganisms load one log cycle (D 1 0 ) in Sheesh Tawoq were 435 and 385 Gy for the Salmonella and E. coli , respectively. The chemical parameters, total acidity and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 12 weeks for Sheesh Tawoq treated with 0 and 2 kGy, and for up to 20 weeks at 1 and 4 mC for samples treated with 4 and 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  6. 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

  7. Powder preparation and compaction behaviour of fine-grained Y-TZP

    NARCIS (Netherlands)

    Groot Zevert, W.F.M.; Winnubst, Aloysius J.A.; Theunissen, G.S.A.M.; Burggraaf, A.J.

    1990-01-01

    Two wet chemical preparation methods are described for yttria-doped tetragonal zirconia powders. Both methods yield powders with an extremely small crystallite size (8 nm) and a narrow size distribution. The agglomerate and aggregate structure of these powders have been investigated by several

  8. Ion chromatographic analysis of high specific activity 18FDG preparations and detection of the chemical impurity 2-deoxy-2-chloro-D-glucose

    International Nuclear Information System (INIS)

    Alexoff, D.L.; Casati, R.; Fowler, J.S.; Wolf, A.P.; Shea, C.; Schlyer, D.J.; Chyng-Yann Shiue

    1992-01-01

    Because of the widespread use of 2-deoxy-2-[ 18 F]fluoro-D-glucose(FDG) prepared by the ''Julich'' method or its variants it was decided necessary to determine the major chemical impurities present in the final product. An analytical system for quantifying FDG was developed using pulsed amperometry after separation by high-performance anion exchange chromotography. With this system a heretofore unidentified impurity, 2-deoxy-2-chloro-D-glucose(C1DG) was found in our preparation and in those from other laboratories using the ''Julich'' method. C1DG arises from C1 - ion displacement during the labeling procedure where C1 - ion comes from several sources, and C1 - ion displacement from the HC1 used in the hydrolysis step. FDG mass was present in the same preparations at a level of ca 1-40 μg. Other major chemical constituents were glucose (ca 1-6 mg) and mannose (ca 10-18 μg). Glycerol, arising from sterilizing filters, was also detected in most preparations. Although C1DG is a chemical impurity which has not been detected previously in nca FDG preparations, its biochemical and pharmacological properties are similar to FDG and 2-deoxy-D-glucose. Thus it is unlikely that the presence of small quantities of C1DG found in typical FDG preparations (ca 100 μg) would have adverse pharmacological or toxicological consequences that would limit continued application of this radiopharmaceutical in basic and clinical studies. (Author)

  9. Effect of gamma irradiation on the microbial load and chemical and sensory properties of locally prepared fast meals

    International Nuclear Information System (INIS)

    Al-Bachir, M.

    2009-01-01

    Locally prepared meals (kubba, borak, cheese borak and sheesh tawoq) were treated with 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1-4 deg. C). Microbiological and chemical analyses were performed on each treated sample immediately after processing, and weekly throughout the storage period, which lasted for 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq. Sensory evaluation and proximate analysis were done within one week after irradiation. Results of the proximate analysis of borak, cheese borak and sheesh tawoq showed that the irradiation doses did not have a significant effect on the moisture, protein and fat contents of meals, whereas for kubba, irradiation decreased the moisture, protein and fat contents. The doses of gamma irradiation selected decreased the microorganism load and increased the shelf life of all meals studied. The radiation doses required to reduce Salmonella and Escherichia coli by one log cycle (D 10 ) in borak were 0.46 and 0.51 kGy, in cheese borak 0.30 and 0.50 kGy and for sheesh tawoq 0.44 and 0.39 kGy, respectively. The three chemical parameters, total acidity, lipid peroxide and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq treated with 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  10. Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang, Xiaojuan; Wang, Bo; Zhan, Zhaolin; Huang, Feng

    2013-01-01

    V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC

  11. Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaojuan [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Wang, Bo [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Zhan, Zhaolin [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Huang, Feng, E-mail: huangfeng@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

    2013-07-01

    V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC.

  12. Enhancement of C/C-LAS joint using aligned carbon nanotubes prepared by injection chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Feng-Ling; Fu, Qian-Gang, E-mail: fuqiangang@nwpu.edu.cn; Feng, Lei; Shen, Qing-Liang

    2016-01-05

    Carbon nanotubes (CNTs) enhanced carbon/carbon-lithium aluminum silicate (C/C-LAS) joint was prepared by a three-step technique of pack cementation, injection chemical vapor deposition (ICVD) and hot-pressing. A layer of aligned CNTs was grown on the surface of SiC coated C/C composites by ICVD method, and the joint was obtained by hot-pressing with magnesium aluminum silicate (MAS) as the interlayer. SEM observation reveals that the introduced CNTs result in the formation of a dense and crack-free CNT/MAS nanocomposite interface between SiC and MAS. Compared with the joints without CNTs, the average shear strength of the joints reinforced by CNTs was improved by 48% accompanied by an obvious change in failure mode from brittle fracture without CNTs to plastic fracture with CNTs. The pulling-out and bridging of CNTs on the fracture surfaces had a positive effect on the strength enhancement of the C/C-LAS joint.

  13. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal, E-mail: kushal@textile.iitd.ernet.in

    2014-09-15

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%.

  14. THE CHEMICAL COMPOSITION AND VARIOUS SAMPLES PREPARATION METHODS FOR In Vitro GAS TEST OF TWO TROPICAL FEEDS

    Directory of Open Access Journals (Sweden)

    J. Daryatmo

    2015-04-01

    Full Text Available A 3x2 factorial experimental design was conducted to evaluate the chemical composition ofSesbania grandiflora (SG and Manihot esculenta Crantz (MEC leaves and to measure the effects ofpreparation and drying methods on the in vitro gas production in the presence and absence of PEG. Thecollected samples were divided into three groups: One group was fresh samples (F. The second groupwas oven-dried at 55°C for 48h (OD and the last group was freeze-dried at –40°C for 72h (FD. Resultsshowed that the mean value of gas production from fresh SG and MEC samples were not significantlyhigher (P<0.05 than from FD and OD samples. In SG and MEC, the mean value of gas production ofFD was not significant compared to OD samples (P>0.05. Gas production from samples added withPEG were higher (P<0.05 than without PEG. In conclusion, the preparation and drying methods of feedsamples could affect the volume of gas production. The addition of PEG in SG and MEC resulted inhigher gas production volumes.

  15. Fabrication of a methanol chemical sensor based on hydrothermally prepared α-Fe₂O₃ codoped SnO₂ nanocubes.

    Science.gov (United States)

    Rahman, Mohammed M; Khan, Sher Bahadar; Jamal, A; Faisal, M; Asiri, Abdullah M

    2012-06-15

    We have prepared calcined α-Fe(2)O(3) codoped SnO(2) nanocubes (NCs) by a hydrothermal method using reducing agents in alkaline medium. The codoped NCs were characterized by UV/vis, FT-IR, and Raman spectroscopy, powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM). They were deposited on a silver electrode (AgE, surface area, 0.0216 cm(2)) to give a sensor with a fast response towards methanol in liquid phase. The sensor also exhibits good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r(2)=0.9809) over the 0.25 mmol L(-1) to 0.25 mol L(-1) methanol concentration range. The sensitivity is ∼5.79 μA cm(-2)mM(-1), and the detection limit is 0.16 ± 0.02 mmol L(-1) (signal-to-noise ratio, at a SNR of 3). We also discuss possible future prospective uses of this codoped semiconductor nanomaterial in terms of chemical sensing. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. TiO2 based photo-catalysts prepared by chemical vapor infiltration (CVI) on micro-fibrous substrates

    International Nuclear Information System (INIS)

    Sarantopoulos, Ch.

    2007-10-01

    This thesis deals with micro-fibrous glass substrates functionalized with TiO 2 . The oxide is deposited as a thin film onto the micro fibres by chemical vapour infiltration (CVI), yielding a photo-catalytic material usable for cleaning polluted air. We studied the relation between the structure of the material and its photo-catalytic efficiency. TiO 2 thin films were prepared at low pressure, in a hot-wall CVD reactor, using Ti(O-iPr) 4 as a precursor. They were characterized by XRD, SEM, EDX, XPS and BET, and by recording the kinetics of decomposition of varied pollutants in solution (orange G, malic acid, imazapyr) and in air (toluene). The conditions favoring the growth of porous films through a columnar growth mode were established by MOCVD-depositing TiO 2 thin films on flat substrates. The subsequent works with micro fibrous thick substrates showed the uniformity of infiltration to be the main factor governing the photo-catalytic efficiency. Operating parameters that optimize infiltration do not yield columnar growth mode. A compromise is necessary. Our photo-catalysts are showing high efficiency comparable, if not higher, to those actually commercialized. These promising results are opening real perspectives for the proposed process. (author)

  17. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    International Nuclear Information System (INIS)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal

    2014-01-01

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%

  18. Structural, optical and electrical properties of CuInS{sub 2} thin films prepared by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Terasako, Tomoaki; Uno, Yuji; Inoue, Seiki; Shirakata, Sho [Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 780-8577 (Japan); Kariya, Tetsuya [Faculty of Science, Kochi University, Akebono-cho, Kochi, 780-8072 (Japan)

    2006-09-15

    Polycrystalline CuInS{sub 2} thin films were prepared by chemical spray pyrolisis (CSP) on glass substrate from the ethanol aqueous solution containing CuCl{sub 2}, InCl{sub 3} and thiourea. Structural, electrical and optical properties were systematically studied in terms of substrate temperature, pH and the ion ratio (Cu/In) of the spray solution. Although the In-rich films were composed of CuInS{sub 2} and In{sub 2}S{sub 3}, the In{sub 2}S{sub 3} content in the film decreased with Cu/In ratio. Appearance of Raman peaks at 288 and 298 cm{sup -1} indicated that the films contained CuInS{sub 2} with chalcopyrite and CuAu phases. Typical grain size in the Cu-rich films was 200 nm. Optical gap energies were approximately 0.1-0.2eV smaller than the bandgap energy of the CuInS{sub 2} bulk crystal. Resistivity of the Cu-rich films without In{sub 2}S{sub 3} secondary phase was 0.2-5 {omega}cm. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Decontamination in preparation for dismantlement - AREVA's chemical decontamination technologies, projects performed and results obtained in the period 2011-2016

    International Nuclear Information System (INIS)

    Topf, C.; Sempere Belda, L.

    2017-01-01

    As a consequence of the nuclear phase-out decreed by the German government, several nuclear power plants in the country have already ceased operation. The remaining ones will cease operation by 2022. This has turned Germany into one of the most active regions worldwide in the field of nuclear decommissioning, with new and emerging technologies being deployed on the field, and already preexisting technologies being put to the test, optimized and developed into full maturity. The chemistry services division of AREVA GmbH has already performed 5 Full System Decontaminations (FSD) in preparation for decommissioning in this period - three in PWRs and two in BWRs - along with other international projects of relevance for decommissioning operations. During a FSD, the complete primary circuit of a nuclear power plant including auxiliary systems is subject to a chemical treatment; designed to remove radioactive matter accumulated onto system surfaces during operation. Through the effective removal of this radioactive accumulations contact dose rates on the different components of the primary circuit can be consistently reduced by factors larger than 50. This results in much lower ambient dose rates and, hence, in very significant dose savings for subsequent decommissioning activities. Additionally, dismantlement operations of large components are considerably simplified and can be performed under conditions that wouldn't have been possible before. The project specific objectives and challenges, the technologies employed, and the results obtained are presented and commented here. (authors)

  20. Characteristics of wetting temperature during spray cooling

    International Nuclear Information System (INIS)

    Mitsutake, Yuichi; Monde, Masanori; Hidaka, Shinichirou

    2006-01-01

    An experimental study has been done to elucidate the effects of mass flux and subcooling of liquid and thermal properties of solid on the wetting temperature during cooling of a hot block with spray. A water spray was impinged at one of the end surfaces of a cylindrical block initially heated at 400 or 500degC. The experimental condition was mass fluxes G=1-9 kg/m 2 s and degrees of subcooling ΔT sub =20, 50, 80 K. Three blocks of copper, brass and carbon steel were prepared. During spray cooling internal block temperature distribution and sputtering sound pressure level were recorded and the surface temperature and heat flux were evaluated with 2D inverse heat conducting analysis. Cooling process on cooling curves is divided into four regimes categorized by change in a flow situation and the sound level. The wetting temperature defined as the wall temperature at a minimum heat flux point was measured over an extensive experimental range. The wetting wall temperature was correlated well with the parameter of GΔT sub . The wetting wall temperature increases as GΔT sub increases and reaches a constant value depending on the material of the surface at higher region of GΔT sub . (author)

  1. Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

    Science.gov (United States)

    Rashid, Zeeshan; Atay, Ipek; Soydan, Seren; Yagci, M. Baris; Jonáš, Alexandr; Yilgor, Emel; Kiraz, Alper; Yilgor, Iskender

    2018-05-01

    Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.

  2. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  3. Possible preparation of wood-plastic composites based on unsaturated polyester resins and styrene by radiation and chemical methods in combination

    International Nuclear Information System (INIS)

    Pesek, M.; Pultar, F.; Jarkovsky, J.; Andr, J.

    1983-01-01

    Using the radiation chemical method it is possible to prepare wood-plastic composites using doses of 1 to 2.5 kGy. The impregnation mixture in the wood gelatinates and subsequent curing using chemical initiators takes place without outflow of the mixture from the wood and without formation of incrustations. The basic components of the impregnation mixtures used were unsaturated polyester resins; styrene or methyl methacrylate was used as the thinner. The proven initiator of polymerization was 2,2'-azobisisobutyronitrile. The technology is described of wood impregnation and radiation or chemical curing. The effects were monitored of viscosity, temperature, radiation dose and the concentrations of the individual components of the impregnation mixtures and initiators of polymerization on the process of the preparation of wood-plastic composites. (M.D.)

  4. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngme [Ewha Womans University, College of Pharmacy (Korea, Republic of); Sah, Eric [University of Notre Dame, College of Science (United States); Sah, Hongkee, E-mail: hsah@ewha.ac.kr [Ewha Womans University, College of Pharmacy (Korea, Republic of)

    2015-11-15

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  5. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    International Nuclear Information System (INIS)

    Lee, Youngme; Sah, Eric; Sah, Hongkee

    2015-01-01

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  6. Wetting of alkanes on water

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, E.; Bonn, D.; Meunier, J.; Shahidzadeh, N. [Ecole Normale Superieure, Laboratoire de Physique Statistique, 24 rue Lhomond, 75231, Cedex 05 Paris (France); Broseta, D.; Ragil, K. [Institut Francais du Petrole, 1-4 avenue de Bois Preau, 92852 Rueil-Malmaison Cedex (France); Dobbs, H.; Indekeu, J.O. [Katholieke Universiteit Leuven, Laboratorium voor Vaste-Stoffysica en Magnetisme, B-3001 Leuven (Belgium)

    2002-04-01

    The wetting behavior of oil on water (or brine) has important consequences for the transport properties of oil in water-containing porous reservoirs, and consequently for oil recovery. The equilibrium wetting behavior of model oils composed of pure alkanes or alkane mixtures on brine is reviewed in this paper. Intermediate between the partial wetting state, in which oil lenses coexist on water with a thin film of adsorbed alkane molecules, and the complete wetting state, in which a macroscopically thick oil layer covers the water, these systems display a third, novel wetting state, in which oil lenses coexist with a mesoscopic (a few-nanometers-thick) oil film. The nature and location of the transitions between these wetting regimes depend on oil and brine compositions, temperature and pressure.

  7. YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films prepared by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Apetrii, Claudia

    2009-11-25

    The discovery of superconductivity in ceramic materials by Bednorz and Mueller in early 1987, immediately followed by Wu et al., who showed that YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) becomes superconducting (92 K) well above the boiling point of nitrogen (77 K) created a great excitement in superconductivity research. Potential applications of high T{sub c}-superconductors require large critical currents and high-applied magnetic fields. Effective ways to increase the critical current density at high magnetic fields in YBCO are the introduction of nanoparticles and chemical substitution of yttrium by other rare earth elements. Since low costs and environmental compatibility are essential conditions for the preparation of long length YBCO films, the cost effective chemical solution deposition (CSD) procedure was selected, given that no vacuum technology is required. To reveal the flexibility and the good optimization possibilities of the CSD approach two main processes were chosen for comparison: a fluorine-free method, namely the polymer-metal precursor technique, and a fluorine-based method, the metalorganic deposition (MOD) using the trifluoroacetates (TFA) technique. Sharp transition temperature widths {delta}T{sub c} of 1.1 K for the polymer metal method, 0.8 K for TFA method and critical current densities J{sub c} of {approx}3.5 MA/cm{sup 2} shows that high quality YBCO thin films can be produced using both techniques. Especially interesting is the magnetic field dependence of the critical current density J{sub c}(B) of the Y(Dy)BCO (80 %) films showing that for the lower magnetic fields the critical current density J{sub c}(B) is higher for a standard YBCO film, but at fields higher than 4.5 T the critical current density J{sub c}(B) of Y(Dy)BCO is larger than that for the YBCO. Above 8 T, J{sub c}(B) of the Y(Dy)BCO film is more than one order of magnitude higher than in pure YBCO film. (orig.)

  8. Antimicrobial activity of novel nanostructured Cu-SiO2 coatings prepared by chemical vapour deposition against hospital related pathogens.

    Science.gov (United States)

    Varghese, Sajnu; Elfakhri, Souad O; Sheel, David W; Sheel, Paul; Bolton, Frederick J Eric; Foster, Howard A

    2013-09-05

    There is increasing recognition that the healthcare environment acts as an important reservoir for transmission of healthcare acquired infections (HCAI). One method of reducing environmental contamination would be use of antimicrobial materials. The antimicrobial activity of thin silica-copper films prepared by chemical vapour deposition was evaluated against standard strains of bacteria used for disinfectant testing and bacteria of current interest in HCAI. The structure of the coatings was determined using Scanning Electron Microscopy and their hardness and adhesion to the substrate determined. Antimicrobial activity was tested using a method based on BS ISO 22196:2007. The coatings had a pale green-brown colour and had a similar hardness to steel. SEM showed nano-structured aggregates of Cu within a silica matrix. A log10 reduction in viability of >5 could be obtained within 4 h for the disinfectant test strains and within 6 h for producing Acinetobacter baumannii, Klebsiella pneumoniae and Stenotrophomonas maltophilia. Activity against the other hospital isolates was slower but still gave log10 reduction factors of >5 for extended spectrum β-lactamase producing Escherichia coli and >3 for vancomycin resistant Enterococcus faecium, methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa within 24 h. The results demonstrate the importance of testing antimicrobial materials destined for healthcare use against isolates of current interest in hospitals as well as standard test strains. The coatings used here can also be applied to substrates such as metals and ceramics and have potential applications where reduction of microbial environmental contamination is desirable.

  9. Wetting of cholesteric liquid crystals.

    Science.gov (United States)

    Silvestre, Nuno M; Figueirinhas Pereira, Maria Carolina; Bernardino, Nelson R; Telo da Gama, Margarida M

    2016-02-01

    We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted, the wetting properties are similar to those of a nematic liquid crystal. If, on the other hand, the anchoring conditions force the distortion of the liquid crystal layers the wetting properties are altered, the free cholesteric-isotropic interface is non-planar and there is a layer of topological defects close to the substrate. These deformations can either promote or hinder the wetting of the substrate by a cholesteric, depending on the properties of the cholesteric liquid crystal.

  10. Testing REACH draft technical guidance notes for conducting chemical safety assessments-the experience of a downstream user of a preparation.

    Science.gov (United States)

    Gade, Anne Lill; Ovrebø, Steinar; Hylland, Ketil

    2008-07-01

    The goal of REACH is the safe use of chemicals. This study examines the efficiency and usefulness of two draft technical guidance notes in the REACH Interim Project 3.2-2 for the development of the chemical safety report and exposure scenarios. A case study was carried out for a paint system for protection of structural steel. The focuses of the study were risk assessment of preparations based on Derived No Effect Level (DNEL) and Predicted No Effect Concentrations (PNEC) and on effective and accurate communication in the supply chain. Exposure scenarios and generic descriptions of uses, risk management measures, and exposure determinants were developed. The study showed that communication formats, software tools, and guidelines for chemical risk assessment need further adjustment to preparations and real-life situations. Web platforms may simplify such communication. The downstream formulator needs basic substance data from the substance manufacturer during the pre-registration phase to develop exposure scenarios for preparations. Default values need to be communicated in the supply chain because these were critical for the derivation of applicable risk management demands. The current guidelines which rely on the available toxicological knowledge are insufficient to advise downstream users on how to develop exposure scenarios for preparations.

  11. Modern sample preparation techniques for gas chromatography-mass spectrometry analysis of environmental markers of chemical warfare agents use

    NARCIS (Netherlands)

    Terzic, O.; de Voogt, P.; Banoub, J.

    2014-01-01

    The chapter introduces problematics of on-site chemical analysis in the investigations of past chemical warfare agents (CWA) events. An overview of primary environmental degradation pathways of CWA leading to formation of chemical markers of their use is given. Conventional and modern sample

  12. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1993-01-01

    Experimental results exploring gravity-driven wetting from instability in a pre-wetted, rough-walled analog fractures such as those at Yucca Mountain are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  13. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1992-01-01

    Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  14. Exposure to wet work in working Australians.

    Science.gov (United States)

    Keegel, Tessa G; Nixon, Rosemary L; LaMontagne, Anthony D

    2012-02-01

    The Australian National Hazard Exposure Worker Surveillance (NHEWS) Survey 2008 was a cross-sectional survey undertaken by Safe Work Australia to inform the development of exposure prevention initiatives for occupational disease. This is a descriptive study of workplace exposures. To assess the occupational and demographic characteristics of workers reporting exposure to wet work. Computer-assisted telephone interviews were conducted with 4500 workers. Two wet work exposure outcomes (frequent washing of hands and duration of time spent at work with the hands immersed in liquids) were analysed. The response rate for the study was 42.3%. For hand-washing, 9.8% [95% confidence interval (CI) 8.9-10.7] reported washing their hands more than 20 times per day. For immersion of hands in liquids, 4.5% (95% CI 3.9-5.1) reported immersion for more than 2 hr per day. Females were more likely to report exposure to frequent hand-washing than males [odds ratio (OR) 1.97, 95% CI 1.49-2.61]. Workers in the lowest occupational skill level jobs were more likely to report increased exposure to hands immersed in liquids than those in the highest (OR 6.41, 95% CI 3.78-10.88). Workers reporting skin exposure to chemicals were more likely to report exposure to hand-washing (OR 3.68, 95% CI 2.91-4.66) and immersion of the hands in liquids (OR 4.09, 95% CI 2.92-5.74). Specific groups of workers reported high levels of exposure to wet work. There were differences between the profiles of workers reporting frequent hand-washing and workers reporting increased duration of exposure to hands immersed in liquids. We also found a high correlation between wet work and chemical exposure. © 2011 John Wiley & Sons A/S.

  15. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    Science.gov (United States)

    Hejazi, Vahid

    Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range of actual and potential applications of superhydrophobic surfaces is diverse including optical, building and architecture, textiles, solar panels, lab-on-a-chip, microfluidic devices, and applications requiring antifouling from biological and organic contaminants. In this thesis, in chapter one, we introduce the general concepts and definitions regarding the wetting properties of the surfaces. In chapter two, we develop novel models and conduct experiments on wetting of composite materials. To design sustainable superhydrophobic metal matrix composite (MMC) surfaces, we suggest using hydrophobic reinforcement in the bulk of the material, rather than only at its surface. We experimentally study the wetting properties of graphite-reinforced Al- and Cu-based composites and conclude that the Cu-based MMCs have the potential to be used in the future for the applications where the wear-resistant superhydrophobicity is required. In chapter three, we introduce hydrophobic coating at the surface of concrete materials making them waterproof to prevent material failure, because concretes and ceramics cannot stop water from seeping through them and forming cracks. We create water-repellant concretes with CA close to 160o using superhydrophobic coating. In chapter four, experimental

  16. Wet Mars, Dry Mars

    Science.gov (United States)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

    2012-12-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

  17. Ferroelectrics onto silicon prepared by chemical solution deposition methods: from the thin film to the self-assembled systems

    Directory of Open Access Journals (Sweden)

    Calzada, M. L.

    2006-06-01

    Full Text Available The work of the authors during the last years on ferroelectric thin and ultra-thin films deposited by Chemical Solution Deposition (CSD onto silicon based substrates is reviewed in this paper. Ferroelectric layers integrated with silicon substrates have potential use in the new micro/nanoelectronic devices. Two hot issues are here considered: 1 the use of low processing temperatures of the ferroelectric film, with the objective of not producing any damage on the different elements of the device heterostructure, and 2 the downscaling of the ferroelectric material with the aim of achieving the high densities of integration required in the next generation of nanoelectronic devices. The UV-assisted Rapid Thermal Processing has successfully been used in our laboratory for the fabrication of ferroelectric films at low temperatures. Preliminary results on the CSD preparation of nanosized ferroelectric structures are shown.

    Este artículo revisa el trabajo realizado por los autores durante los últimos años sobre lámina delgada y ultra-delgada ferroeléctrica preparada mediante el depósito químico de disoluciones (CSD sobre substratos de silicio. Las películas ferroeléctricas integradas con silicio tienen potenciales usos en los nuevos dispositivos micro/nanoelectrónicos. Dos aspectos claves son aquí considerados: 1 el uso de bajas temperaturas de procesado de la lámina ferroeléctrica, con el fin de no dañar los diferentes elementos que forman la heteroestructura del dispositivo y 2 la disminución de tamaño del material ferroeléctrico con el fin de conseguir las altas densidades de integración requeridas en la próxima generación de dispositivos nanoelectróncos. Los procesos térmicos rápidos asistidos con irradiación UV se están usando en nuestro laboratorio para conseguir la fabricación del material ferroeléctrico a temperaturas bajas compatibles con la tecnología del silicio. Se muestran resultados preliminares sobre

  18. Restart of the chemical preparation process for the fabrication of ZnO varistors for ferroelectric neutron generator power supplies

    International Nuclear Information System (INIS)

    Lockwood, Steven John

    2005-01-01

    To date, all varistors used in ferroelectric neutron generators have been supplied from a single, proprietary source, General Electric Corporate Research and Development (GE CR and D). To protect against the vulnerability of a single source, Sandia initiated a program in the early 1980's to develop a second source for this material. A chemical preparation process for making homogeneous, high purity ZnO-based varistor powder was generated, scaled to production quantities, and transferred to external suppliers. In 1992, the chem-prep varistor program was suspended when it appeared there was sufficient inventory of GE CR and D material to supply ferroelectric neutron generator production for many years. In 1999, neutron generator production schedules increased substantially, resulting in a predicted exhaustion of the existing supply of varistor material within five years. The chem-prep program was restarted in January, 2000. The goals of the program were to (1) duplicate the chem-prep powder synthesis process that had been qualified for WR production, (2) demonstrate sintered billets from the chem-prep powder met requirements, (3) develop a process for rod fabrication and demonstrate that all component specifications could be met, and (4) optimize the process from powder synthesis through component fabrication for full-scale production. The first three of these goals have been met and are discussed in this report. A facility for the fabrication of production quantities of chem-prep powder has been established. All batches since the restart have met compositional requirements, but differences in sintering behavior between the original process and the restarted process were noted. Investigation into the equipment, precipitant stoichiometry, and powder processing procedures were not able to resolve the discrepancies. It was determined that the restarted process, which incorporated Na doping for electrical stability (a process that was not introduced until the end of the

  19. Preparation of Polymeric Resin Beads Using Gamma Irradiation and Chemical Processes for Use in the Recovery of Some Alkali Metal Ions

    International Nuclear Information System (INIS)

    El-Nahas, H. H.; Khalil, F. H.; Ibrahim, G. M.; El-Gammal, B.

    2007-01-01

    Syntheses of resin beads from unsaturated polyester and urea-formaldehyde were carried out by dispersion polymerization. The reaction was performed through gamma irradiation and chemical processing. Factors affecting the reaction and syntheses parameters that are the type and viscosity of dispersant, irradiation dose and agitation rate on the resin beads size were thoroughly investigated. The resulting resin beads were smooth on their spherical surface and the beads diameters were in the range 2-200μm. Some measurements such as beads diameter, surface hardness and scanning electron microscopy were studied. The bead diameter was generally decreased with increasing concentration and viscosity of the dispersant and agitation rate. A comparison study between irradiation and chemical processes for resin beads synthesis was discussed to identify the suitable process for preparing a resin beads in a pilot scale. The different methods of preparation were tried to be applied in the recovery of Li + , Na+, k + and Cs + ions from acidic media.

  20. PDMS Network Structure-Property Relationships: Influence of Molecular Architecture on Mechanical and Wetting Properties

    Science.gov (United States)

    Melillo, Matthew Joseph

    Poly(dimethylsiloxane) (PDMS) is one of the most common elastomers, with applications ranging from sealants and marine-antifouling coatings to medical devices and absorbents for water treatment. Fundamental understanding of how liquids spread on the surface of and absorb into and leach out of PDMS networks is of critical importance for the design and use in another application - microfluidic devices. The growing use of PDMS in microfluidic devices raises the concern that some researchers may use this material without fully understanding all of its advantages, drawbacks, and intricacies. The primary goal of this Ph.D. dissertation is to elucidate PDMS network molecular structure to macroscopic property relationships and to demonstrate how molecular architecture can alter dynamic mechanical and wetting characteristics. We prepare PDMS materials by using vinyl/ tetrakis(dimethylsiloxy)silane (TDSS) and silanol/ tetraethylorthosilicate (TEOS) combinations of PDMS end-groups and crosslinkers as two model systems. Under constant curing conditions, we systematically study the effects of polymer molecular weight, loading of crosslinker, and end-group chemical functionality on the extent of gelation and the dynamic mechanical and water wetting properties of end-linked PDMS networks. The extent of the gelation reaction is determined using the Soxhlet extraction to quantify the amount of material that did and did not participate in the crosslinking reactions, termed the gel and sol fractions, respectively. We use the Miller-Macosko model in conjunction with the gel fraction and precise chemical composition (i.e., stoichiometric ratio and molecular weight) to determine the fractions of elastic and pendant material, the molecular weight between chemical crosslinks, and the average effective functionality of the crosslinker molecule. Based on dynamic mechanical testing, we find that the maximum storage moduli are achieved at optimal stoichiometric conditions in the vinyl

  1. Possible preparation of wood-plastic materials based on unsaturated polyester resins and methyl metacrylate, by radiation and chemical methods in combination

    International Nuclear Information System (INIS)

    Pesek, M.

    1982-01-01

    The preparation of wood-plastic combinations (WPC) using combined methods for curing intermediate products and final products is described. In the first step, impregnated wood was irradiated using doses of 1 to 10 kGy in the presence of chemical initiators of polymerization. Thereafter, curing of this partly cured impregnating mixture was accomplished in the wood at elevated temperatures with the aid of chemical initiators of polymerization. Impregnation mixtures based on unsaturated polyester resins and methyl methacrylate, and the wood species European Beech (Fagus silvatica) and Black Alder (Alnus glutinosa) were used. The results indicate that this method of preparing WPC allows substantially lower radiation doses to be used, i.e., doses in the range of 1 to 2.5 kGy. These doses gelatinate the impregnation mixture in the wood so that the subsequent curing by chemical polymerization initiators proceeds without the impregnation mixture flowing out of the wood, and without forming bosses and incrustations. Intermediate products and wood products needing no further finish may thus be prepared: in some cases regrinding or repolish is sufficient. The possibility of using impregnation mixtures based on various unsaturated polyester resins was investigated, and the influence on the curing process of temperature, polymerization initiator concentration, methyl methacrylate concentration, inhibitor concentration, and other factors affecting curing was evaluated. (author)

  2. Study of polycaprolactone wet electrospinning process

    Directory of Open Access Journals (Sweden)

    E. Kostakova

    2014-08-01

    Full Text Available Wet electrospinning is a useful method for 3-dimensional structure control of nanofibrous materials. This innovative technology uses a liquid collector instead of the metal one commonly used for standard electrospinning. The article compares the internal structural features of polycaprolactone (PCL nanofibrous materials prepared by both technologies. We analyze the influence of different water/ethanol compositions used as a liquid collector on the morphology of the resultant polycaprolactone nanofibrous materials. Scanning electron micro-photographs have revealed a bimodal structure in the wet electrospun materials composed of micro and nanofibers uniformly distributed across the sample bulk. We have shown that the full-faced, twofold fiber distribution is due to the solvent composition and is induced and enhanced by increasing the ethanol weight ratio. Moreover, the comparison of fibrous layers morphology obtained by wet and dry spinning have revealed that beads that frequently appeared in dry spun materials are created by Plateau-Rayleigh instability of the fraction of thicker fibers. Theoretical conditions for spontaneous and complete immersion of cylindrical fibers into a liquid collector are also derived here.

  3. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces

    KAUST Repository

    Domingues, Eddy

    2017-06-05

    Omniphobic surfaces, i.e. which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact, and preventing applications in harsh environments. There is, thus, a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nano-texturing rather than via chemical make-up, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising of pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibited apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, e.g. hydrodynamic drag reduction and membrane distillation.

  4. Combining Chemical Information Literacy, Communication Skills, Career Preparation, Ethics, and Peer Review in a Team-Taught Chemistry Course

    Science.gov (United States)

    Jones, Mary Lou Baker; Seybold, Paul G.

    2016-01-01

    The widely acknowledged need to include chemical information competencies and communication skills in the undergraduate chemistry curriculum can be accommodated in a variety of ways. We describe a team-taught, semester-length course at Wright State University which combines chemical information literacy, written and oral communication skills,…

  5. Sol-gel process preparation and evaluation of the analytical performances of an hydrazine specific chemical sensor

    International Nuclear Information System (INIS)

    Gojon, C.

    1996-12-01

    The realisation of optical fibers active chemical collector to analyze hydrazine in line, in the spent fuel reprocessing process is the subject of this work. The p.dimethyl-amino-benzaldehyde has been chosen as reagent for its chemical and optical properties

  6. Chemical stability of insulin. 2. Formation of higher molecular weight transformation products during storage of pharmaceutical preparations.

    Science.gov (United States)

    Brange, J; Havelund, S; Hougaard, P

    1992-06-01

    Formation of covalent, higher molecular weight transformation (HMWT) products during storage of insulin preparations at 4-45 degrees C was studied by size exclusion chromatography. The main products are covalent insulin dimers (CID), but in protamine-containing preparations the concurrent formation of covalent insulin-protamine (CIP) products takes place. At temperatures greater than or equal to 25 degrees C parallel or consecutive formation of covalent oligo- and polymers can also be observed. Rate of HMWT is only slightly influenced by species of insulin but varies with composition and formulation, and for isophane (NPH) preparations, also with the strength of preparation. Temperature has a pronounced effect on CID, CIP, and, especially, covalent oligo- and polymer formation. The CIDs are apparently formed between molecules within the hexameric unit common for all types of preparations and rate of formation is generally faster in glycerol-containing preparations. Compared with insulin hydrolysis reactions (see the preceding paper), HMWT is one order of magnitude slower, except for NPH preparations.

  7. WET SOLIDS FLOW ENHANCEMENT; SEMIANNUAL

    International Nuclear Information System (INIS)

    Hugo S Caram; Natalie Foster

    1998-01-01

    The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and may require accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained

  8. Influence of chemistry on wetting dynamics of nanotextured hydrophobic surfaces.

    Science.gov (United States)

    Di Mundo, Rosa; Palumbo, Fabio; d'Agostino, Riccardo

    2010-04-06

    In this work, the role of a chemical parameter, such as the degree of fluorination, on the wetting behavior of nanotextured hydrophobic surfaces is investigated. Texture and chemistry tuning of the surfaces has been accomplished with single batch radiofrequency low-pressure plasma processes. Polystyrene substrates have been textured by CF(4) plasma etching and subsequently covered by thin films with a tunable F-to-C ratio, obtained in discharges fed with C(4)F(8)-C(2)H(4). Measurements of wetting dynamics reveal a regime transition from adhesive-hydrophobic to slippery-superhydrophobic, i.e., from wet to non wet states, as the F-to-C rises at constant topography. Such achievements are strengthened by calculation of the solid fraction of surface water contact area applying Cassie-Baxter advancing and receding equations to water contact angle data of textured and flat reference surfaces.

  9. Model determination and validation for reactive wetting processes

    Energy Technology Data Exchange (ETDEWEB)

    Yost, F.G.; O`Toole, E.J.; Sackinger, P.A. [Sandia National Labs., Albuquerque, NM (United States); Swiler, T.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering

    1998-01-01

    It is shown that dissolutive wetting initially yields a metastable equilibrium. A compact model for the kinetics of approach to this metastable state is described. The technique for constructing these kinetics stems from the early work of Onsager and begins with a relationship for the entropy production. From this, a coupled set of nonlinear, ordinary differential equations can be written directly. The equations are solved numerically for the wetted area and compared with experimental data. The model captures many of the subtle complexities of dissolutive wetting such as multiple metastable states. Sessile drop experiments involving a variety of Bi-Sn alloys on solid Bi substrates were performed. Substrates prepared from small and large-grained polycrystals and single crystals were used to measure equilibrium and metastable contact angles and estimate the surface tension and equilibrium contact angle of the solid-liquid interface. The substrates were also used to investigate the coupling of the dissolution and wetting processes and to investigate the effect of substrate grain size on wetting. It was determined that the equilibrium wetting geometry is independent of linear scale and that grain size has little influence on wetting or dissolution in the Bi-Sn system. To investigate the atomic behavior of liquids at interfaces during wetting, the authors simulated wetting in the Ag-Cu system using molecular dynamics with atomic potentials and observed both atomic dynamics and structural correlations of the liquid-solid interface. The authors found that spreading is prompted by interactions between the liquid and the substrate surface that cause the liquid layer in contact with the substrate to take on some of the symmetry of the substrate surface and result in the formation of a liquid monolayer that extends beyond the major part of the liquid droplet.

  10. Accelerated Drying of Wet Boots

    National Research Council Canada - National Science Library

    Dyck, Walter

    2002-01-01

    .... One such material is sodium polyacrylate. Because recent field trials with Canadian Forces soldiers have reconfirmed that donning wet combat boots is very uncomfortable, a study was done to assess the efficacy of using sodium polyacrylate...

  11. Wetting on structured substrates

    International Nuclear Information System (INIS)

    Dietrich, S; Popescu, M N; Rauscher, M

    2005-01-01

    Chemically patterned surfaces are of significant interest in the context of microfluidic applications, and miniaturization of such devices aims at generating structures on the nano-scale. Whereas on the micron scale purely macroscopic descriptions of liquid flow are valid, on the nanometre scale long-ranged inter-molecular interactions, thermal fluctuations such as capillary waves, and finally the molecular structure of the liquid become important. We discuss the most important conceptual differences between flow on chemically patterned substrates on the micron scale and on the nanometre scale, and formulate four design issues for nanofluidics related to channel width, channel separation, and channel bending radius. As a specific example of nano-scale transport we present a microscopic model for the dynamics of spreading of monolayers on homogeneous substrates. Kinetic Monte Carlo simulations of this model on a homogeneous substrate reveal a complex spatio-temporal structure of the extracted monolayer, which includes the emergence of interfaces and of scaling properties of density profiles. These features are discussed and rationalized within the corresponding continuum limit derived from the microscopic dynamics. The corresponding spreading behaviour on a patterned substrate is briefly addressed

  12. Wet-Bulb-Globe Temperature Data Report

    Science.gov (United States)

    2015-03-01

    Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT...Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT K2 WBGT GMT millibars deg F...Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT K2 WBGT GMT millibars deg F deg F deg

  13. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid (OA) and sodium iodide (NaI). It is demonstrated that the combination of a reducing acid, OA, and NaI is indispensable for effective reduction of GO in the current study and this unique combination (1) allows for tunable control over the volume of the thus-prepared graphene assemblies and (2) enables 3D graphene assemblies to be prepared from the GO suspension with a wide range of concentrations (0.1 to 4.5 mg mL-1). To the best of our knowledge, the GO concentration of 0.1 mg mL-1 is the lowest GO concentration ever reported for preparation of 3D graphene assemblies. The thus-prepared 3D graphene assemblies exhibit low density, highly porous structures, and electrically conducting properties. As a proof of concept, we show that by infiltrating a responsive polymer of polydimethylsiloxane (PDMS) into the as-resulted 3D conducting network of graphene, a conducting composite is obtained, which can be used as a sensing device for differentiating organic solvents with different polarity. © 2012 The Royal Society of Chemistry.

  14. Preparation and characterization of high surface area activated carbon from Fox nut (Euryale ferox shell by chemical activation with H3PO4

    Directory of Open Access Journals (Sweden)

    Arvind Kumar

    Full Text Available Activated carbons were prepared from Fox nutshell by chemical activation with H3PO4 in N2 atmosphere and their characteristics were studied. The effects of activation temperature and impregnation ratio were examined. N2 adsorption isotherms characterized the surface area, total pore volume, micropore volume and pore size distribution of activated carbons. Activated carbon was produced at 700 °C with a 1.5 impregnation ratio and one hour of activation time has found 2636 m2/g and 1.53 cm3/g of highest BET surface area and total pore volume, respectively. The result of Fourier-infrared spectroscopy analysis of the prepared activated carbon confirmed that the carbon has abundant functional groups on the surface. Field emission scanning electron micrographs of the prepared activated carbon showed that a porous structure formed during activation. Keywords: Activated carbons, Fox nutshell, Chemical activation, H3PO4, Activated carbon, Surface chemistry, Porous structure

  15. Preparation of carbon dioxide adsorbents from the chemical activation of urea-formaldehyde and melamine-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Drage; A. Arenillas; K.M. Smith; C. Pevida; S. Piippo; C.E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2007-01-15

    Adsorption is considered to be one of the more promising technologies for the capture of CO{sub 2} from flue gases. In general, nitrogen enrichment is reported to be effective in enhancing the specific adsorbent-adsorbate interaction for CO{sub 2}. Nitrogen enriched carbons were produced from urea-formaldehyde and melamine-formaldehyde resins polymerised in the presence of K{sub 2}CO{sub 3} as a chemical activation agent, with activation undertaken over a range of temperatures. CO{sub 2} adsorption capacity was determined to be dependent upon both textural properties and more importantly nitrogen functionality. Adsorbents capable of capturing above 8 wt.% CO{sub 2} at 25{sup o}C were produced from the chemical activation of urea-formaldehyde resin at 500{sup o}C. Chemical activation seems to produce more effective adsorbents than CO{sub 2} activation. 29 refs., 4 figs., 3 tabs.

  16. Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods - Chemical properties

    DEFF Research Database (Denmark)

    Zhang, Hong; Jacobsen, Charlotte; Pedersen, Lars Saaby

    2006-01-01

    margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25øC for 12wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by the conventional methods (chemical interesterification and physical blending......In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table...... interesterified fat had higher PV in weeks4, 8 and10 than the margarines produced from the enzymatically interesterified fats and the physically blended fat. These differences were not caused by different contents of tocopherols in the hardstocks. The differences between the processes for chemical and enzymatic...

  17. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin; Chen, Guoying; Hedhili, Mohamed N.; Zhang, Hongnan; Wang, Peng

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid

  18. STORAGE OF CHEMICALLY PRETREATED WHEAT STRAW – A MEANS TO ENSURE QUALITY RAW MATERIAL FOR PULP PREPARATION

    Directory of Open Access Journals (Sweden)

    Terttu Heikkilä

    2010-07-01

    Full Text Available The aim of this study was to evaluate effects of chemical pretreatment and storage on non-wood pulping and on pulp quality. The processes studied were hot water treatment followed by alkaline peroxide bleaching or soda cooking. The results showed that it is possible to store wheat straw outside for at least one year without significant changes in the raw material chemical composition and without adverse effects on the resulting pulp quality. The results are significant to the industry using non-woods to ensure the availability and the quality of the raw-material throughout the year in spite of the short harvesting time.

  19. Synthesis and characterization of CoPt nanoparticles prepared by room temperature chemical reduction with PAMAM dendrimer as template.

    Science.gov (United States)

    Wan, Haiying; Shi, Shifan; Bai, Litao; Shamsuzzoha, Mohammad; Harrell, J W; Street, Shane C

    2010-08-01

    We describe an approach to synthesize monodisperse CoPt nanoparticles with dendrimer as template by a simple chemical reduction method in aqueous solution using NaBH4 as reducing agent at room temperature. The as-made CoPt nanoparticles buried in the dendrimer matrix have the chemically disordered fcc structure and can be transformed to the fct phase after annealing at 700 degrees C. This is the first report of dendrimer-mediated room temperature synthesis of monodisperse magnetic nanoparticles in aqueous solution.

  20. Development of Wet Noodles Based on Cassava Flour

    Directory of Open Access Journals (Sweden)

    Akhmad Z. Abidin

    2013-04-01

    Full Text Available Cassava is one of Indonesia’s original commodities and contains good nutrition and has high productivity and a relatively low price. Cassava flour has a high potential as a substitute for imported wheat flour that is widely used in noodle production. The main purpose of this research was to develop wet noodles from cassava flour that can compete with wet noodles from wheat flour. The research consisted of experiments with several variations of composition and production method for producing cassava flour-based wet noodles. The best result was then examined for its nutritional value, economical value, and market response, and also a comparison was made between the prepared wet noodles and the standard noodles made from wheat flour. The analysis was based on five characteristics: taste, texture, chewiness, aroma, and appearance. Relations between these characteristics with composition, materials used, and methods applied are discussed. The developed cassava flour-based wet noodle meets physical, nutritional, and economical standards. Raw materials of the noodle were cassava flour and a wheat flour composite with a 5:1 ratio, egg, gluten, soda-ash, water, and vegetable oil, while the process was completed in multiple stages. Market response showed that the cassava flour-based wet noodles were 80% similar to wheat-flour noodles.

  1. Surface Modifications in Adhesion and Wetting

    Science.gov (United States)

    Longley, Jonathan

    Advances in surface modification are changing the world. Changing surface properties of bulk materials with nanometer scale coatings enables inventions ranging from the familiar non-stick frying pan to advanced composite aircraft. Nanometer or monolayer coatings used to modify a surface affect the macro-scale properties of a system; for example, composite adhesive joints between the fuselage and internal frame of Boeing's 787 Dreamliner play a vital role in the structural stability of the aircraft. This dissertation focuses on a collection of surface modification techniques that are used in the areas of adhesion and wetting. Adhesive joints are rapidly replacing the familiar bolt and rivet assemblies used by the aerospace and automotive industries. This transition is fueled by the incorporation of composite materials into aircraft and high performance road vehicles. Adhesive joints have several advantages over the traditional rivet, including, significant weight reduction and efficient stress transfer between bonded materials. As fuel costs continue to rise, the weight reduction is accelerating this transition. Traditional surface pretreatments designed to improve the adhesion of polymeric materials to metallic surfaces are extremely toxic. Replacement adhesive technologies must be compatible with the environment without sacrificing adhesive performance. Silane-coupling agents have emerged as ideal surface modifications for improving composite joint strength. As these coatings are generally applied as very thin layers (coatings using the buckling instability formed between two materials of a large elastic mismatch. The elastic modulus is found to effectively predict the joint strength of an epoxy/aluminum joint that has been reinforced with silane coupling agents. This buckling technique is extended to investigate the effects of chemical composition on the elastic modulus. Finally, the effect of macro-scale roughness on silane-reinforced joints is investigated

  2. 13-year overview of serious adverse drug reactions following subcutaneous specific immunotherapy with a chemically modified allergen preparation.

    Science.gov (United States)

    Distler, Andreas; Pappelendam, Debbie

    The Paul-Ehrlich-Institut (PEI) published an analysis of reports of adverse drug reactions (ADRs) in 2001 with test and therapy allergens from the period from 1991 to 2000. Possible risk factors were evaluated for the ADR reports classified as "serious". During the analyzed period, modified semi-depot preparations (allergoids) induced between 0.01 % and 0.0005 % serious systemic reactions, i. e. one serious ADR occurred in 10,000 to 200,000 injections. No information was provided regarding the respective incidences in relation to the individual companies or preparations. Within the scope of a 13-year analysis (2001-2013), the serious ADRs were analysed at HAL for the allergoid preparations PURETHAL® Pollen and Mites. As in the analysis of PEI, the frequency of serious ADRs was based on the estimated number of administered injections. A total of 46 cases with serious ADRs were received. In 26 % of the cases, a serious ADR occurred during initial treatment after the first injection. In 82.6 % of the cases, the serious ADR occurred within the 30-minute observation period in the practice. Adrenaline was administered as emergency treatment in seven cases. Hospitalisations were initiated by the treating physician or by patients themselves in 45 cases. The duration of the hospital stay varied from a few hours up to three days for further monitoring. Serious ADRs occurred in 11 cases with mites and in 35 cases with pollen. If it is assumed that there are six injections in each vial, this yields an incidence of 0.00061 % (1 : 164,000). The frequency with mites (0.00093 %) was slightly higher than with pollen (0.00055 %). The allergoid preparations (pollen and mite allergens) showed a very low risk of serious ADRs, which was close to the lower level of incidence of 0.0005 % for allergoid preparations published by the PEI.

  3. Effect of Drug Active Substance Particles on Wet Granulation Process.

    Czech Academy of Sciences Publication Activity Database

    Bělohlav, Z.; Břenková, L.; Hanika, Jiří; Durdil, P.; Rapek, P.; Tomášek, V.

    2007-01-01

    Roč. 85, A7 (2007) , s. 974-980 ISSN 0263-8762 Institutional research plan: CEZ:AV0Z40720504 Keywords : wet granulation * control * active substance Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.837, year: 2007

  4. Physico-chemical effects of supercritical carbon dioxide post polymerization treatment on HCl-doped polyaniline prepared via oxidative chemical polymerization

    Science.gov (United States)

    Fernando, J. G.; Vequizo, R. M.; Odarve, M. K. G.; Sambo, B. R. B.; Alguno, A. C.; Malaluan, R. M.; Candidato, R. T., Jr.; Gambe, J. E.; Jabian, M.; Paylaga, G. J.; Bagsican, F. R. G.; Miyata, H.

    2015-06-01

    Polyanilinefilms doped with varying HClconcentrations (0.2 M, 0.6 M and 1.0 M) were synthesized on glass substrates via oxidative polymerization of aniline. The films were treated with supercritical carbon dioxide (SC-CO2) at 30 MPa and 40°C for 30 minutes. Their structural, optical and morphological properties were studied and compared to conventionally prepared polyanilinefilms using FTIR analysis, UVVisspectroscopy and scanning electron microscopy. It was observed that supercritical carbon dioxide (SC-CO2) could interact with PANI films that consequently altered the bandgapsand changed the film thickness. SC-CO2 treatment also increased the oxidation level of polyanilinefilms and modified the morphology of polyanilinefilm doped with 1M HCl.

  5. Thick Fe2O3, Fe3O4 films prepared by the chemical solution deposition method

    Czech Academy of Sciences Publication Activity Database

    Buršík, Josef; Košovan, P.; Šubrt, Jan

    2006-01-01

    Roč. 39, č. 2 (2006), s. 85-94 ISSN 0928-0707 R&D Projects: GA ČR GA203/01/0408 Institutional research plan: CEZ:AV0Z40320502 Keywords : chemical solution deposition * thick films * alpha-Fe2O3 Subject RIV: CA - Inorganic Chemistry Impact factor: 1.009, year: 2006

  6. Wetting of Water on Graphene

    KAUST Repository

    Bera, Bijoyendra; Shahidzadeh, Noushine; Mishra, Himanshu; Bonn, Daniel

    2016-01-01

    The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measuring the mass of water vapor adsorbing to graphene flakes of different thickness at different relative humidities. Our experiments unambiguously show that the thinnest of graphene flakes do not adsorb water, from which it follows that the contact angle of water on these flakes is ~180o. Thicker flakes of graphene nanopowder, on the other hand, do adsorb water. A calculation of the van der Waals (vdW) interactions that dominate the adsorption in this system confirms that the adhesive interactions between a single atomic layer of graphene and water are so weak that graphene is superhydrophobic. The observations are confirmed in an independent experiment on graphene-coated water droplets that shows that it is impossible to make liquid 'marbles' with molecularly thin graphene.

  7. Wetting of Water on Graphene

    KAUST Repository

    Bera, Bijoyendra

    2016-11-28

    The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measuring the mass of water vapor adsorbing to graphene flakes of different thickness at different relative humidities. Our experiments unambiguously show that the thinnest of graphene flakes do not adsorb water, from which it follows that the contact angle of water on these flakes is ~180o. Thicker flakes of graphene nanopowder, on the other hand, do adsorb water. A calculation of the van der Waals (vdW) interactions that dominate the adsorption in this system confirms that the adhesive interactions between a single atomic layer of graphene and water are so weak that graphene is superhydrophobic. The observations are confirmed in an independent experiment on graphene-coated water droplets that shows that it is impossible to make liquid \\'marbles\\' with molecularly thin graphene.

  8. Infrared and Raman spectroscopy study of AsS chalcogenide films prepared by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Mochalov, Leonid; Dorosz, Dominik; Kudryashov, Mikhail; Nezhdanov, Aleksey; Usanov, Dmitry; Gogova, Daniela; Zelentsov, Sergey; Boryakov, Aleksey; Mashin, Alexandr

    2018-03-15

    AsS chalcogenide films, where As content is 60-40at.%, have been prepared via a RF non-equilibrium low-temperature argon plasma discharge, using volatile As and S as the precursors. Optical properties of the films were studied in UV-visible-NIR region in the range from 0.2 to 2.5μm. Infrared and Raman spectroscopy have been employed for the elucidation of the molecular structure of the newly developed material. It was established that PECVD films possess a higher degree of transparency (up to 80%) and a wider transparency window (>20μm) in comparison with the "usual" AsS thin films, prepared by different thermal methods, which is highly advantageous for certain applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Preparation of atomically clean and flat Si(1 0 0) surfaces by low-energy ion sputtering and low-temperature annealing

    International Nuclear Information System (INIS)

    Kim, J.C.; Ji, J.-Y.; Kline, J.S.; Tucker, J.R.; Shen, T.-C.

    2003-01-01

    Si(1 0 0) surfaces were prepared by wet-chemical etching followed by 0.3-1.5 keV Ar ion sputtering, either at elevated or room temperature (RT). After a brief anneal under ultrahigh vacuum (UHV) conditions, the resulting surfaces were examined by scanning tunneling microscopy. We find that wet-chemical etching alone cannot produce a clean and flat Si(1 0 0) surface. However, subsequent 300 eV Ar ion sputtering at room temperature followed by a 700 deg. C anneal yields atomically clean and flat Si(1 0 0) surfaces suitable for nanoscale device fabrication

  10. Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forest

    Science.gov (United States)

    YIQING LI; MING XU; XIAOMING ZOU

    2006-01-01

    Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C allocation and the response of different C pools to nutrient addition in these forests remain poorly understood. We measured soil organic carbon (SOC), litterfall, root biomass, microbial biomass and soil physical and chemical properties in a wet tropical forest from May 1996 to July...

  11. Preparation and characterization of SnO2 thin film by chemical bath deposition method for solar cell application

    International Nuclear Information System (INIS)

    Wan Mohd Zin Wan Yunus; Saeideh Ebrahimiasl; Anuar Kassim

    2009-01-01

    Full text: Tin oxide thin films were synthesized by chemical bath deposition method on glass substrate .The as-deposited thin films were characterized for compositional, structural, surface morphological, optical and electrical properties. The X-ray diffraction patterns of the sample indicate that all samples are polycrystalline structure. AFM images show that the films consist of small uniform grains and are free of pinholes. (author)

  12. Preparation and characterization of perovskite structure lanthanum gallate and lanthanum aluminate based oxides

    OpenAIRE

    Li, Shuai

    2009-01-01

    The present work was initiated to study the synthesis and properties of lanthanum gallate based oxides as intermediate temperature electrolyte for solid oxide fuel cells. The wet chemical method, polymer complexing route, was used to prepare the precursor powders. To further investigate the polymer complexing method, it was also applied to the preparation of lanthanum aluminate based oxides.   Single perovskite phase La0.8Sr0.2Ga0.83Mg0.17O2.815 can be prepared by the polymer complexing meth...

  13. Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching

    International Nuclear Information System (INIS)

    Iatsunskyi, Igor; Kempiński, Mateusz; Nowaczyk, Grzegorz; Jancelewicz, Mariusz; Pavlenko, Mykola; Załęski, Karol; Jurga, Stefan

    2015-01-01

    Highlights: • Porous silicon/TiO 2 nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO 2 nanocomposites were established. • Valence-band XPS maximums for PSi/TiO 2 nanocomposites were found and analyzed. - Abstract: PSi/TiO 2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO 2 nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO 2 nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, O 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO 2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO 2 nanocomposites electronic structure. Surface defects states of Ti 3+ at PSi/TiO 2 nanocomposites were identified by analyzing of XPS valence band spectra

  14. Preparation and Characterization of Conducting Polymer Latices by Chemical Polymerization of Aniline or Anisidine in Presence of Latex: Study of Their Electroactivity and Anti-Corrosion Properties

    Directory of Open Access Journals (Sweden)

    Bakhshali Massoumi

    2013-06-01

    Full Text Available Poly (vinylacetate-co-butylmethacrylate was prepared in presence of potassium persulphate as an oxidizing agent in aqueous solution of dodecylbenzene sulfonate sodium as an emulsifying agent. Then, aniline was polymerized by chemical oxidation method at three different concentrations of aniline monomer (0.1, 0.2 and 0.3 M in toluene in presence of poly(vinylacetate-co-butylmethacrylate in order to obtain polyaniline/poly(vinylacetate-co-butylmethacrylate. To prepare conducting-latex of polyanisidine/poly(vinylacetate-co-butylmethacrylate the same method was employed as above for aniline monomer in obtaining conducting polyaniline/poly(vinylacetate-co-butylmethacrylate latex. In addition, the purification of conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was conducted and preparation of tin layer films of conducting-latex polymers was carried out by casting method on glassy lames. The electroactivity properties of the prepared latex-polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate were investigated by cyclic voltammetery (CV. The voltamogrames showed that the latex films were electroactive. Because of conductivity and electroactivity, the obtained films may find applications in anti-corrosion coatings. The anti-corrosion properties of conducting-latex polymers were studied on aluminum surface by impedance technique. The structure of the prepared conducting-latex polymers was confirmed by Fourier transform infrared (FTIR. Finally, the electrical conductivity of synthesized conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was measured by four probe technique.

  15. Does bedding promote pine survival and growth on ditched wet sands?

    Science.gov (United States)

    Ralph A. Klawitter

    1970-01-01

    Results from a study of prepared beds for planting slash pine on a wet sandy flat in Florida were inconclusive. Early growth was improved, but survival was not; and differences between a bedded site and an unbedded site were slight.

  16. Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

    2005-01-01

    Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

  17. Analyte-triggered luminescence of Eu{sup 3+} ions encapsulated in Nafion membranes -preparation of hybrid materials from in membrane chemical reactions-

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Sánchez, Rocío, E-mail: raguilar@ifuap.buap.mx [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Zelocualtecatl-Montiel, Iván [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Gálvez-Vázquez, María de Jesús [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico); Silva-González, Rutilo [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico)

    2017-04-15

    The possibility to perform chemical reactions inside polymer materials opens a unique opportunity to control and prepare materials for diverse solid-state applications. Based on the affinity of Eu{sup 3+} ions for oxygen functionalities, in this work we report the luminescence enhancement of Eu{sup 3+} ions inserted in Nafion membranes (Naf/Eu{sup 3+}) by in-situ complexing to oxalate. The formation of a europium-oxalate type complex enhances Eu{sup 3+} luminescence emission, which could be exploited for the construction of devices for oxalate sensing and the fabrication of highly luminescent materials. Possible analytical applications of Naf/Eu{sup 3+} membranes were evaluated by fluorescence spectroscopy through the linear response with concentration. The complex formation was followed by infrared spectroscopy and SEM-EDS analysis. - Highlights: • Luminescence enhancement by complexation of Eu{sup 3+} ions to oxalate inside Nafion. • Performance of chemical reactions inside Nafion/polymer membranes. • An easy and novel method to prepare luminescent solid devices. • Possibility to develop luminescent sensors by analyte-triggered optical response.

  18. Chemically Methylated and Reduced Pectins: Preparation and Characterisation by 1H-NMR Spectroscopy, Enzymatic Degradation and Gelling Properties

    DEFF Research Database (Denmark)

    Rosenbohm, Christoph; Lundt, Inge; Christensen, T.M.I.E.

    2003-01-01

    with lower DM. A simple method for determination of DM by 1H-NMR spectroscopy is presented. New modified pectins have been prepared by treatment of pectins having different DM’s with NaBH4 to reduce selectively the methyl esters to primary alcohols in the presence of free acids. The degree of reduction (DR......) and the DM of the remaining carboxylic acids could likewise be determined by 1H-NMR spectroscopy. The new reduced pectins can be tolerated by the pectin degrading enzymes polygalacturonase PGI and PGII as well as by pectin lyase, all from Aspergillus niger, but the enzymes exhibit lower specific activities...

  19. Physical-chemical and technological aspects of the preparation of think layers of the high temperature superconductors Bi-Sr-Ca-Cu-O by method of metal organic vapour phase epitaxy

    International Nuclear Information System (INIS)

    Stejskal, J.; Nevriva, M.; Leitner, J.

    1995-01-01

    The method of metal organic vapour phase epitaxy (MO VPE) was used for preparation of think layers of the high temperature superconductors Bi-Sr-Ca-Cu-O. The suitable chemical precursors (β-diketonates) on the literature data and of the own thermodynamic calculations were selected. The optimal thermodynamic data and thermodynamic stability of the prepared samples were determined

  20. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann

    2012-12-01

    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.