WorldWideScience

Sample records for assisted chemical separation

  1. Waste remediation using in situ magnetically assisted chemical separation

    International Nuclear Information System (INIS)

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

  2. Radiolysis and hydrolysis of magnetically assisted chemical separation particles

    International Nuclear Information System (INIS)

    The magnetically assisted chemical separation (MACS) process is designed to separate transuranic (TRU) elements out of high-level waste (HLW) or TRU waste. Magnetic microparticles (1--25 μm) were coated with octyl (phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP) and tested for removing TRU elements from acidic nitrate solutions. The particles were contacted with nitric acid solutions and Hanford plutonium finishing plant (PFP) simulant, irradiated with a high intensity 60Co γ-ray source, and evaluated for effectiveness in removing TRU elements from 2m HNO3 solutions. The resistance of the coatings and magnetic cores to radiolytic damage and hydrolytic degradation was investigated by irradiating samples of particles suspended in a variety of solutions with doses of up to 5 Mrad. Transmission electron microscopy (TEM), magnetic susceptibility measurements, and physical observations of the particles and suspension solutions were used to assess physical changes to the particles. Processes that affect the surface of the particles dramatically alter the binding sites for TRU in solution. Hydrolysis played a larger role than radiolysis in the degradation of the extraction capacity of the particles

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

    International Nuclear Information System (INIS)

    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

  4. Development program for magnetically assisted chemical separation: Evaluation of cesium removal from Hanford tank supernatant

    International Nuclear Information System (INIS)

    Magnetic particles (MAG*SEPSM) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEPSM particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEPSM particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEPSM particles with a gamma dose equivalent to 100 cycles of use. This irradiation decreased the loading capacity and distribution ratios for the particles by greater than 75%. The particles demonstrated high sensitivity to radiolytic damage due to the degradation of the polymeric regions. These results were supported by optical microscopy measurements. Overall, use of magnetic particles for cesium separation under nuclear waste conditions was found to be marginally effective

  5. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  6. Isotope separation by chemical exchange

    International Nuclear Information System (INIS)

    Nitrogen-15 and oxygen-18 enrichment by chemical exchange in the (NO/NO2) - (H2O/HNO3) system, using a laboratory-scale experimental plant and a cascade for production of two isotopes, is presented. The results obtained from the laboratory-scale plant indicate that optimal flow rate for 15N separation is 1.55 - 1.86 ml/cm2 · min at 8 - 10 M/l nitric acid and 63.4 mg at. oxygen/cm2 · min for 18O separation at 5.8 M/l nitric acid. The height equivalent to a theoretical plate (HETP) of 4.11 - 4.56 cm is in good agreement with other published data for 15N separation using exchange column with Helipak packing. The HETP of 7.74 - 10.58 cm for 18O separation is greater by 20 - 30 % than those presented by Saxena and Taylor for 'Helipak' column packing, but in good agreement with the HRTP published by Borisov et al. on 'Levina' column packing. The HETP obtained for 15N separation by the production plant is in the range 11.5 - 13.8 cm at a flow rate of 2.2 ml HNO3(10M/l)/cm2 · min for the first column and 4.4 - 4.7 cm at a flow rate of 1.66 ml HNO3(10M/l)/cm2 · min for the second column. The optimal flow rate for 18O separation by the production plant is about 63 mg at. oxygen/cm2 · min (1.01 ml HNO3/cm2 · min). Enrichment of 13C and 18O by chemical exchange of carbon dioxide with its monoethanolamine carbamate in methanol and di-n-butylamine carbamate in triethylamine has also been studied, and optimum operating conditions for the separation of 13C in a packed column was determined. The HETP obtained for the 13C in a packed column was determined. The HETP obtained for the 13C separation column is 3.62 - 8.26 cm at a flow rate of 1.1 - 4.0 mmol carbamate/cm2 · min using the same column packing as for 15N and 18O separation, that is, stainless steel triangular wire springs (2.3 x 2.3 x 0.2 mm). (author)

  7. Chemical reaction and separation method

    NARCIS (Netherlands)

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.

    2005-01-01

    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  8. Microwave-assisted Chemical Transformations

    Science.gov (United States)

    In recent years, there has been a considerable interest in developing sustainable chemistries utilizing green chemistry principles. Since the first published report in 1986 by Gedye and Giguere on microwave assisted synthesis in household microwave ovens, the use of microwaves as...

  9. Chemical separation of disc components using RAVE

    CERN Document Server

    Wojno, Jennifer; Steinmetz, Matthias; McMillan, Paul J; Matijevič, Gal; Binney, James; Wyse, Rosemary F G; Boeche, Corrado; Just, Andreas; Grebel, Eva K; Siebert, Arnaud; Bienaymé, Olivier; Gibson, Brad K; Zwitter, Tomaž; Bland-Hawthorn, Joss; Navarro, Julio F; Parker, Quentin A; Reid, Warren; Seabroke, George; Watson, Fred

    2016-01-01

    We present evidence from the RAdial Velocity Experiment (RAVE) survey of chemically separated, kinematically distinct disc components in the solar neighbourhood. We apply probabilistic chemical selection criteria to separate our sample into $\\alpha$-low (`thin disc') and $\\alpha$-high (`thick disc') components. Using newly derived distances, which will be utilized in the upcoming RAVE DR5, we explore the kinematic trends as a function of metallicity for each of the disc components. For our thin disc stars, we find a negative trend in the mean rotational velocity ($V_{\\mathrm{\\phi}}$) as a function of iron abundance ([Fe/H]). We measure a positive trend in $\\partial V_{\\mathrm{\\phi}}$/$\\partial$[Fe/H] for the thick disc, consistent with results from high-resolution surveys. We also find differences between the chemical thin and thick discs in all three components of velocity dispersion. We discuss the implications of an $\\alpha$-low, metal-rich population originating from the inner Galaxy, where the orbits of ...

  10. Spark assisted chemical engraving (SACE) in microfactory

    Science.gov (United States)

    Wüthrich, R.; Fujisaki, K.; Couthy, Ph; Hof, L. A.; Bleuler, H.

    2005-10-01

    Spark assisted chemical engraving (SACE) is a method for 3D microstructuring of glass or other non-conductive materials with high aspect ratio and smooth surface quality. It is applicable for rapid prototyping of microfluidic devices, for MEMS interfacing and similar applications. Typical feature size is in the hundreds of micrometres, down to a few tens of micrometres. It is a table-top technology requiring no clean rooms and no masks and with very modest space usage. It is thus well suited for microfactories. This paper gives a basic introduction to SACE and some machining examples.

  11. Estimation of Separation Buffers for Wind-Prediction Error in an Airborne Separation Assistance System

    Science.gov (United States)

    Consiglio, Maria C.; Hoadley, Sherwood T.; Allen, B. Danette

    2009-01-01

    Wind prediction errors are known to affect the performance of automated air traffic management tools that rely on aircraft trajectory predictions. In particular, automated separation assurance tools, planned as part of the NextGen concept of operations, must be designed to account and compensate for the impact of wind prediction errors and other system uncertainties. In this paper we describe a high fidelity batch simulation study designed to estimate the separation distance required to compensate for the effects of wind-prediction errors throughout increasing traffic density on an airborne separation assistance system. These experimental runs are part of the Safety Performance of Airborne Separation experiment suite that examines the safety implications of prediction errors and system uncertainties on airborne separation assurance systems. In this experiment, wind-prediction errors were varied between zero and forty knots while traffic density was increased several times current traffic levels. In order to accurately measure the full unmitigated impact of wind-prediction errors, no uncertainty buffers were added to the separation minima. The goal of the study was to measure the impact of wind-prediction errors in order to estimate the additional separation buffers necessary to preserve separation and to provide a baseline for future analyses. Buffer estimations from this study will be used and verified in upcoming safety evaluation experiments under similar simulation conditions. Results suggest that the strategic airborne separation functions exercised in this experiment can sustain wind prediction errors up to 40kts at current day air traffic density with no additional separation distance buffer and at eight times the current day with no more than a 60% increase in separation distance buffer.

  12. Continuous intensified separations for the chemicals industry

    NARCIS (Netherlands)

    Ngene, I.S.; Roelands, C.P.M.

    2012-01-01

    Today, a lot of effort is going into intensifying reactions within the chemicals industry. Intensified processes are expected to delìver significant improvements in manufacturing processes, reducing equipment size and waste streams and increasing product yields and thereby delivering more sustainabl

  13. Chemical Separation of Fixed Tissue Using Thermolysin

    OpenAIRE

    Anahita Dua; Desai, Sapan S.

    2013-01-01

    Thermolysin is a metallopeptidase used to cleave peptide bonds at specific junctions. It has previously been used to cleave specific amino acid sequences found at the junction of the sensory epithelium and underlying stroma of unfixed otolithic organs of the vestibular system. We have used thermolysin to separate sensory epithelium from the underlying stroma in fixed cristae ampullares of mouse, rat, gerbil, guinea pig, chinchilla, and tree squirrel, thus removing the saddle-shaped curvature ...

  14. Chemical Separation of Fixed Tissue Using Thermolysin

    Directory of Open Access Journals (Sweden)

    Anahita Dua

    2013-01-01

    Full Text Available Thermolysin is a metallopeptidase used to cleave peptide bonds at specific junctions. It has previously been used to cleave specific amino acid sequences found at the junction of the sensory epithelium and underlying stroma of unfixed otolithic organs of the vestibular system. We have used thermolysin to separate sensory epithelium from the underlying stroma in fixed cristae ampullares of mouse, rat, gerbil, guinea pig, chinchilla, and tree squirrel, thus removing the saddle-shaped curvature of the sensory organ and creating a flattened sensory epithelium preparation. This permits visualization of the entire sensory organ in a single mount and facilitates proper morphometric analysis.

  15. Ethanol-assisted gel chromatography for single-chirality separation of carbon nanotubes

    Science.gov (United States)

    Zeng, Xiang; Hu, Jinwen; Zhang, Xiao; Zhou, Naigen; Zhou, Weiya; Liu, Huaping; Xie, Sishen

    2015-10-01

    Surfactants or polymers are usually used for the liquid processing of carbon nanotubes for their structure separation. However, they are difficult to remove after separation, affecting the intrinsic properties and applications of the separated species. Here, we report an ethanol-assisted gel chromatography for the chirality separation of single-walled carbon nanotubes (SWCNTs), in which ethanol is employed to finely tune the density/coverage of sodium dodecyl sulfate (SDS) on nanotubes, and thus the interactions between SWCNTs and an allyl dextran-based gel. Incrementally increasing the ethanol content in a low-concentration SDS eluent leads to successive desorption of the different structure SWCNTs adsorbed on the gel, and to achieve multiple distinct (n, m) single-chirality species. The use of ethanol enables the working concentration of SDS to be reduced dramatically and also avoids the introduction of other surfactants or chemical reagents. More importantly, ethanol can be easily removed after separation. The ability of ethanol to tune the interactions between SWCNTs and the gel also gives a deeper insight into the separation mechanism of SWCNTs using gel chromatography.Surfactants or polymers are usually used for the liquid processing of carbon nanotubes for their structure separation. However, they are difficult to remove after separation, affecting the intrinsic properties and applications of the separated species. Here, we report an ethanol-assisted gel chromatography for the chirality separation of single-walled carbon nanotubes (SWCNTs), in which ethanol is employed to finely tune the density/coverage of sodium dodecyl sulfate (SDS) on nanotubes, and thus the interactions between SWCNTs and an allyl dextran-based gel. Incrementally increasing the ethanol content in a low-concentration SDS eluent leads to successive desorption of the different structure SWCNTs adsorbed on the gel, and to achieve multiple distinct (n, m) single-chirality species. The use of

  16. Chemical separation of carbon -14 in radwastes

    International Nuclear Information System (INIS)

    Carbon-14 has a long half-life of 5730 years and decays by beta emission of 156KeV to the stable nuclide, Nitrogen-14. Carbon-14 is produced mostly by the neutron activation of naturally occurring oxygen-17 in water molecules of the reactor coolant and Nitrogen-14 from nitrogen gas dissolved in the reactor coolant. Most of these carbon-14 are known to be discharged as gaseous wastes. The chemical forms of the gaseous emissions of carbon-14 from PWR stations range from 10∼26% as 14CO2 and 74∼90% as 14CH4 and other hydrocarbons, compared to about 95% as 14CO2 and 5% as 14CH4 and other hydrocarbons in BWR station gaseous emissions. Knowles reported that although the exact nature of these organic compounds was not identified, most of the carbon-14 was present as forms of organic species in a PWR primary coolant. Praudic measured the contents of the total organic and inorganic carbon-14 in waste trench leachates of New York commercial LLW disposal site and found that 74 ∼ 98% of carbon-14 was organic. In 1991, Dayal and Kirby reported that carbon-14 identified in LLW trench leachates from the Maxi Fiats site were carbonate and bicarbonate as inorganic carbon-14 and citric acid and palmitic acid as organic carbon-14. Thus concentrated Boric acid waste solutions(CB) which has generated from domestic NPP were classified into organic and inorganic carbon-14 with wet oxidation method in order to grasping a existing ratio of organic carbon-14 from total one due to affecting an environment

  17. Chemical exchange equilibria in isotope separation. Part I : Evaluation of separation factors

    International Nuclear Information System (INIS)

    The theory of chemical exchange equilibria as applied to the isotope separation processes and the isotope effects on equilibrium constants of different exchange reactions has come a long way since its inception by Urey and Rittenberg. An attempt has been made to bring relevant information together and present a unified approach to isotopic chemical exchange equilibrium constant evaluation and its implications to separation processes. (auth.)

  18. Some Chemical Group Separations of Radioactive Trace Elements

    International Nuclear Information System (INIS)

    As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials

  19. Computer aided design, analysis and experimental investigation of membrane assisted batch reaction-separation systems

    DEFF Research Database (Denmark)

    Mitkowski, Piotr Tomasz; Buchaly, Carsten; Kreis, Peter; Jonsson, Gunnar Eigil; Gorak, Andrzej; Gani, Rafiqul

    2009-01-01

    Membrane assisted batch reaction operation offers an interesting option for equilibrium limited reaction systems in chemical and biochemical manufacturing by selective removal of one of the products and thereby increasing the product yield. The design of such hybrid systems need to take into...... account the performance of each constituent element and the optimisation of the design must take into consideration their interdependency. In this paper use of a membrane, to assist in the synthesis of propyl-propionate is investigated through the use of a hybrid process design framework, which consists...... and separation functionalities and to design/analyse the hybrid scheme. The generated hybrid scheme has been validated through experiments involving an esterification reaction....

  20. Silicon Sheets By Redox Assisted Chemical Exfoliation

    CERN Document Server

    Tchalala, Mohamed Rachid; Enriquez, Hanna; Kara, Abdelkader; Lachgar, Abdessadek; Yagoubi, Said; Foy, Eddy; Vega, Enrique; Bendounan, Azzedine; Silly, Mathieu G; Sirotti, Fausto; Nitshe, Serge; Chaudanson, Damien; Jamgotchian, Haik; Aufray, Bernard; Mayne, Andrew J; Dujardin, Gérald; Oughaddou, Hamid

    2013-01-01

    In this paper, we report the direct chemical synthesis of silicon sheets in gram-scale quantities by chemical exfoliation of pre-processed calcium di-silicide (CaSi2). We have used a combination of X-ray photoelectron spectroscopy, transmission electron microscopy and Energy-dispersive X-ray spectroscopy to characterize the obtained silicon sheets. We found that the clean and crystalline silicon sheets show a 2-dimensional hexagonal graphitic structure.

  1. Laser isotope separation - a new class of chemical process

    International Nuclear Information System (INIS)

    Lasers may soon find several applications in chemical processing. The applications that have attracted the most research funding to date involve isotope separation for the nuclear industry. These isotopes have an unusually high value (≥$1000/kg) compared to bulk chemicals (∼$1/kg) and are generally required in very large quantities. In a laser isotope separation process, light is used to convert a separation that is very difficult or even impossible by conventional chemical engineering techniques to one that is readily handled by conventional separation technology. For some isotopes this can result in substantial capital and energy savings. A uranium enrichment process developed at the Lawrence Livermore National Laboratory is the closest to commercialization of the large scale laser isotope separation processes. Of particular interest to the Canadian nuclear industry are the laser separation of deuterium, tritium, zirconium-90 and carbon-14. In this paper, the basic principles behind laser isotope separation are reviewed and brief dscriptions of the more developed processes are given

  2. Sensitive chemical compass assisted by quantum criticality

    Science.gov (United States)

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

    2012-02-01

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

  3. Sensitive Chemical Compass Assisted by Quantum Criticality

    CERN Document Server

    Cai, C Y; Quan, H T; Sun, C P

    2011-01-01

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

  4. Identification of heavy and superheavy nuclides using chemical separator systems

    Science.gov (United States)

    Türler, Andreas

    1999-11-01

    With the recent synthesis of superheavy nuclides produced in the reactions 48Ca+238U and 48Ca+242,244Pu, much longer-lived nuclei than the previously known neutron-deficient isotopes of the heaviest elements have been identified. Half-lives of several hours and up to several years have been predicted for the longest-lived isotopes of these elements. Thus, the sensitivity of radiochemical separation techniques may present a viable alternative to physical separator systems for the discovery of some of the predicted longer-lived heavy and superheavy nuclides. The advantages of chemical separator systems in comparison to kinematic separators lie in the possibility of using thick targets, high beam intensities spread over larger target areas and in providing access to nuclides emitted under large angles and low velocities. Thus, chemical separator systems are ideally suited to study also transfer and (HI, αxn) reaction products. In the following, a study of (HI, αxn) reactions will be presented and prospects to chemically identify heavy and superheavy elements discussed.

  5. Actinides(3)/lanthanides(3) separation by nano-filtration assisted by complexation

    International Nuclear Information System (INIS)

    In France, one of the research trend concerning the reprocessing of spent nuclear fuel consists to separate selectively the very radio-toxic elements with a long life to be recycled (Pu) or transmuted (Am, Cm, Np). The aim of this thesis concerns the last theme about actinides(III)/lanthanides(III) separation by a process of nano-filtration assisted by complexation. Thus, a pilot of tangential membrane filtration was designed and established in a glove box at the ATALANTE place of CEA-Marcoule. Physico-chemical characterisation of the Desal GH membrane (OSMONICS), selected to carry out actinides(III)/lanthanides(III) separation, was realized to determine the zeta potential of the active layer and its resistance to ionizing radiations. Moreover, a parametric study was also carried out to optimize the selectivity of complexation, and the operating conditions of complex retention (influences of the transmembrane pressure, solute concentration, tangential velocity and temperature). Finally, the separation of traces of Am(III) contained in a mixture of lanthanides(III), simulating the real load coming from a reprocessing cycle, was evaluated with several chelating agents such as poly-amino-carboxylic acids according to the solution acidity and the [Ligand]/[Cation(III)] ratio. (author)

  6. Isotope separation by chemical exchange process: Final technical report

    International Nuclear Information System (INIS)

    The feasibility of a chemical exchange method for the separation of the isotopes of europium was demonstrated in the system EuCl2-EuCl3. The single stage separation factor, α, in this system is 1.001 or 1.0005 per mass unit. This value of α is comparable to the separation factors reported for the U4+ - U6 and U3+ - Y4+ systems. The separation of the ionic species was done by precipitation of the Eu2+ ions or by extraction of the Eu3+ ions with HDEHP. Conceptual schemes were developed for a countercurrent reflux cascades consisting of solvent extraction contractors. A regenerative electrocel, combining simultaneous europium reduction, europium oxidation with energy generation, and europium stripping from the organic phase is described. 32 refs., 22 figs., 6 tabs

  7. Chemical recycling of municipal waste slag by using phase separation

    OpenAIRE

    Nanba, Tokuro; Kuroda, Yutaro; Sakida, Shinichi; Benino, Yasuhiko

    2009-01-01

    A chemical recycling method by using phase separation was applied to municipal waste slags. Glasses were prepared from incineration ash and ash-melted slag, where B(2)O(3) was added to promote phase separation. The glasses were heat-treated at temperatures higher than their glass transition temperatures, and they were soaked in hydrochloric acid, leaching CaO, Fe(2)O(3), K(2)O, and S. Transparent and colorless solids containing ca. 80 mass% of SiO(2) were successfully obtained as residues. It...

  8. Separation of radionuclides from chemical and electrochemical decontamination wastes

    International Nuclear Information System (INIS)

    A multistage process combining photocatalytic degradation of organic complexes and complexants followed by separation of the radionuclides by ion exchange was developed and tested for the treatment of aqueous waste from chemical or electrochemical decontamination of NPP primary circuit internals. In these solutions, both the oxalic and citric acids could be quantitatively degraded within 10-12 hours of irradiation by 254 nm UV radiation in the presence of TiO2 photocatalyst. For the group radionuclides separation, a standard cation exchanger was found to be preferable to any of the set of the tested inorganic-organic composite absorbers. (author)

  9. Chemical separation procedure proposed for studies of bohrium

    International Nuclear Information System (INIS)

    Off-line and on-line studies have been performed with radioactive tracers of various elements to develop a chemical separation procedure for bohrium (element 107). The proposed procedure is intended for use in the fast solvent extraction system SISAK. The homologs technetium and rhenium were used to model the chemical behavior of bohrium. The results show that high decontamination factors can be obtained for technetium and rhenium with respect to unwanted contaminants like trivalent actinides, polonium and the Group 5 elements. (author)

  10. Mixture pseudo-chromatographic separation by matrix-assisted diffusion ordered spectroscopy

    International Nuclear Information System (INIS)

    Summary: Pseudo-separation for phenylalanine (Phe), ibuprofen (Ibu), capsaicin (Cap) and norfloxacin (Nor) were studied by sodium dodecyl sulfate (SDS) or hydroxypropyl-beta -cyclodextrin (HP beta CD) assisted diffusion ordered spectroscopy (DOSY). Stokes-Einstein equation shows a linear relationship between the logarithms of apparent diffusion coefficients and logarithms of molecular weight (Mw). However, with matrix added, block factors became the important factors than molecular weight. Pseudo-separation was improved by SDS or HP beta CD assist. Research showed different separation mechanism for SDS and HP beta CD-assisted DOSY. The former used different lipo-hydro partition coefficient, and the latter used complexing mechanism. (author)

  11. Ligand-assisted capillary electrophoresis separations of the lanthanides

    International Nuclear Information System (INIS)

    Capillary electrophoresis is used with simple organic ligands added to the electrolyte matrix to achieve separation of the individual lanthanide cations. Results for acetate (AC-) and malonate (MA-) yield good resolution for the lighter lanthanides, but not the heavier lanthanides. In contrast, α-hydroxyisobutyrate (HIB-) gives complete resolution for all of the lanthanide cations. These results are related to the complexation chemistry between the lanthanides and the ligands across the lanthanide series. In addition, preliminary results for lanthanide separations using AC- in mixed methanol:water solvent systems are provided. The presence of methanol improves resolution but slows the separation. (author)

  12. Inequalities and separations among assisted capacities of quantum channels

    CERN Document Server

    Bennett, C H; Shor, P W; Smolin, J A; Bennett, Charles H.; Devetak, Igor; Shor, Peter W.; Smolin, John A.

    2004-01-01

    We exhibit discrete memoryless quantum channels whose quantum capacity assisted by two-way classical communication, $Q_2$, exceeds their unassisted one-shot Holevo capacity $C_H$. These channels may be thought of as having a data input and output, along with a control input that partly influences, and a control output that partly reveals, which of a set of unitary evolutions the data undergoes en route from input to output. The channel is designed so that the data's evolution can be exactly inferred by a classically coordinated processing of 1) the control output, and 2) a reference system entangled with the control input, but not from either of these resources alone. Thus a two-way classical side channel allows the otherwise noisy evolution of the data to be corrected, greatly increasing the capacity. The same family of channels provides examples where the classical capacity assisted by classical feedback, $C_B$, and the quantum capacity assisted by classical feedback $Q_B$, both exceed $C_H$. A related chan...

  13. A Survey of Chemical Separation in Accreting Neutron Stars

    CERN Document Server

    Mckinven, Ryan; Medin, Zach; Schatz, Hendrik

    2016-01-01

    The heavy element ashes of rp-process hydrogen and helium burning in accreting neutron stars are compressed to high density where they freeze, forming the outer crust of the star. We calculate the chemical separation on freezing for a number of different nuclear mixtures resulting from a range of burning conditions for the rp-process. We confirm the generic result that light nuclei are preferentially retained in the liquid and heavy nuclei in the solid. This is in agreement with the previous study of a 17-component mixture of rp-process ashes by Horowitz et al. (2007), but extends that result to a much larger range of compositions. We also find an alternate phase separation regime for the lightest ash mixtures which does not demonstrate this generic behaviour. With a few exceptions, we find that chemical separation reduces the expected $Q_{\\rm imp}$ in the outer crust compared to the initial rp-process ash, where $Q_{\\rm imp}$ measures the mean-square dispersion in atomic number $Z$ of the nuclei in the mixtu...

  14. Design of Uranium Isotope Separation Plant by Chemical Exchange

    International Nuclear Information System (INIS)

    The methodology to design a solvent extraction plant for uranium isotope separation by chemical exchange is outlined. This process involves the calculator of the number of stages,the capacity of the plant,the flow rates,and reflux ration in banks of mixer settlers or pulse column used in such a plant. The feed is introduced at the middle of the plant,and the product is withdrawn at one end and the tailings at another. The redox reaction system selected is U(IV)-U(VI) and the equilibrium data of the 40% tri-n-octylamine (TOA) in benzene as the organic phase and 4 M HCI as the aqueous phase are used for the design of the real plant. The resulting analysis for the uranium isotope separation shows that more than 4000 number of stages are required and the reflux ratio is around 700 to produce only 1m3 of product containing 3% of U235 and 0,3% of U235 in the tailings. It is also known that the larger the isotope separation constant the smaller the number of stages needed. The method of design can be used for other systems where the isotope separation constants are more favorable

  15. Production and chemical separation of 48 V radioisotope

    International Nuclear Information System (INIS)

    The positron emitter 48 V isotope (T1/2=16 d, γ-lines: 511 keV (100%), 983.5 (100%), 1312 (97.6%)) is of interest in several fields of science. This is valid for transmitting scans in the validation process of PET-camera by positron emission. It can be used as an industrial monitoring isotope by its γ-photons having high energy and intensity. Also, it is suitable for biological study since it is the only radioisotope of the biological trace element vanadium which can be a radiotracer due to its longer half-life. The 48 V was produced by nat Ti (d,xn)48 V nuclear reaction in the U-120 cyclotron with activity of 6 mCi. The energy of irradiating beam was 13 MeV, its intensity was 5 μA and the metallic Ti target dimensions were 16 x 11 x 2 mm. For target cooling, the water circulation in the back side was used. After 3 cooling days, only 48 V, and some 46 Sc (T1/2 = 84 d), produced by the side nuclear reaction 48 Ti (d,α)46 Sc were found in the target. For the preparation of 48 V source, the Ti target was dissolved in HF and sulfuric acid. The ion exchange separation was developed for both dissolving methods. The dissolution of the chemically resistant Ti target is so violent in concentrated (3.5 % m/m) HF, that it is necessary to be carried out in polyethylene tube in order to avoid the splash of the dissolved target. An anion exchange column, Dowex 1-8 (size 100-200 mesh, length 12 cm, ID 10 mm, treated 1 day earlier, prepared fresh), was used for separation in HF media. The reduced ionic form of Ti bonds to resin, therefore the dissolved target was saturated with sulfur-dioxide produced in the Kipp-equipment by the following chemical reaction: Na2SO3 + 2 HCl → 2 NaCl + H2SO3. The treated solution was diluted to a concentration of 2 mol/l of HF and the same concentration of the HF was used as an eluent for separation. Flow rate of the elution was 1 ml/min. The eluate was cooled fractionally. The fractions were measured by γ-spectrometry, which detected only 48

  16. Overview of the French program in chemical separations and transmutation

    International Nuclear Information System (INIS)

    A long-range effort has begun in France that is aimed at the reduction of the volume and activity level of wastes containing long half-life radionuclides. This effort constitutes the SPIN (SeParations-INcineration) Program which investigates separations techniques that can improve current reprocessing technologies coupled with destruction of long-lived species through transmutation. Removal and destruction of specific radionuclides (e.g., neptunium, americium, technetium, iodine, cesium, and strontium) will be emphasized. Advanced solvent extraction chemistry focusing, for example, on development and implementation of diamides for actinide-lanthanide separations constitutes an important component of the SPIN program. The second component of the program focuses on inventory reductions through transmutation of such long-lived nuclides in fast reactor systems (Super Phenix). Accelerator-based systems are also being evaluated as a possible long-term option. Both of these components of the SPIN program are aimed at further reduction of the potential radiotoxicity and radiological impact of high-level wastes destined for geological storage. In this presentation, major activities of the SPIN Program will be described with emphasis on activities related to advanced chemical separations

  17. Generalized Least Energy of Separation for Desalination and Other Chemical Separation Processes

    Directory of Open Access Journals (Sweden)

    Karan H. Mistry

    2013-05-01

    Full Text Available Increasing global demand for fresh water is driving the development and implementation of a wide variety of seawater desalination technologies driven by different combinations of heat, work, and chemical energy. This paper develops a consistent basis for comparing the energy consumption of such technologies using Second Law efficiency. The Second Law efficiency for a chemical separation process is defined in terms of the useful exergy output, which is the minimum least work of separation required to extract a unit of product from a feed stream of a given composition. For a desalination process, this is the minimum least work of separation for producing one kilogram of product water from feed of a given salinity. While definitions in terms of work and heat input have been proposed before, this work generalizes the Second Law efficiency to allow for systems that operate on a combination of energy inputs, including fuel. The generalized equation is then evaluated through a parametric study considering work input, heat inputs at various temperatures, and various chemical fuel inputs. Further, since most modern, large-scale desalination plants operate in cogeneration schemes, a methodology for correctly evaluating Second Law efficiency for the desalination plant based on primary energy inputs is demonstrated. It is shown that, from a strictly energetic point of view and based on currently available technology, cogeneration using electricity to power a reverse osmosis system is energetically superior to thermal systems such as multiple effect distillation and multistage flash distillation, despite the very low grade heat input normally applied in those systems.

  18. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  19. Azo dye decolorization assisted by chemical and biogenic sulfide

    International Nuclear Information System (INIS)

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

  20. Study on microwave assisted process in chemical extraction

    International Nuclear Information System (INIS)

    The microwave assisted process is a revolutionary method of extraction that reduces the extraction time to as little as a few seconds, with up to a ten-fold decrease in the use of solvents. The target material is immersed in solvent that is transparent to microwaves, so only the target material is heated, and because of the microwaves tend to heat the inside of the material quickly, the target chemical are expelled in a few seconds. benefits from this process include significant reductions in the amount of energy required and substantial reductions in the cost and dispose of hazardous solvents. A thorough review has been displayed on: using the microwave in extraction, applications of microwave in industry, process flow diagram, mechanism of the process and comparison between microwave process and other extraction techniques (soxhlet, steam distillation and supercritical fluid). This review attempts to summarize the studies about microwave assisted process as a very promising technique. (Author)

  1. Chemically assisted ion beam etching of polycrystalline and (100)tungsten

    Science.gov (United States)

    Garner, Charles

    1987-01-01

    A chemically assisted ion-beam etching technique is described which employs an ion beam from an electron-bombardment ion source and a directed flux of ClF3 neutrals. This technique enables the etching of tungsten foils and films in excess of 40 microns thick with good anisotropy and pattern definition over areas of 30 sq mm, and with a high degree of selectivity. (100) tungsten foils etched with this process exhibit preferred-orientation etching, while polycrystalline tungsten films exhibit high etch rates. This technique can be used to pattern the dispenser cathode surfaces serving as electron emitters in traveling-wave tubes to a controlled porosity.

  2. Actinides(3)/lanthanides(3) separation by nano-filtration assisted by complexation; Separation actinides(3)lanthanides(3) par nanofiltration assistee par complexation

    Energy Technology Data Exchange (ETDEWEB)

    Sorin, A

    2006-07-01

    In France, one of the research trend concerning the reprocessing of spent nuclear fuel consists to separate selectively the very radio-toxic elements with a long life to be recycled (Pu) or transmuted (Am, Cm, Np). The aim of this thesis concerns the last theme about actinides(III)/lanthanides(III) separation by a process of nano-filtration assisted by complexation. Thus, a pilot of tangential membrane filtration was designed and established in a glove box at the ATALANTE place of CEA-Marcoule. Physico-chemical characterisation of the Desal GH membrane (OSMONICS), selected to carry out actinides(III)/lanthanides(III) separation, was realized to determine the zeta potential of the active layer and its resistance to ionizing radiations. Moreover, a parametric study was also carried out to optimize the selectivity of complexation, and the operating conditions of complex retention (influences of the transmembrane pressure, solute concentration, tangential velocity and temperature). Finally, the separation of traces of Am(III) contained in a mixture of lanthanides(III), simulating the real load coming from a reprocessing cycle, was evaluated with several chelating agents such as poly-amino-carboxylic acids according to the solution acidity and the [Ligand]/[Cation(III)] ratio. (author)

  3. Chemical separation and nuclear transmutation of by-product actinides

    International Nuclear Information System (INIS)

    The paper presents the most important results and conclusions of the assessment studies carried out by the Joint Research Centre-Ispra and by other organizations on the advanced waste disposal strategy based on chemical separation of By-product Actinides (BPA's) from high level liquid waste (HLLW) and their transmutation in nuclear reactors. The technological developments required for the implementation of this strategy have been identified: they concern mainly fuel reprocessing, BPA recovery from all important waste streams and fuel refabrication. After consideration of different strategies for BPA transmutation, the homogeneous recycling in FBR's appears to be most suitable due to its transmutation rate and the compatibility of BPA's with its fuel cycle. The fuel cycle with transmutation has been compared with an advanced reference fuel cycle on the basis of costs and risks. The large effort required for the development and implementation of this new fuel cycle, the increased costs operating the fuel cycle compared with the marginal benefits in the long-term risk of geological disposal, make this strategy not very attractive

  4. A Performance Assessment of a Tactical Airborne Separation Assistance System using Realistic, Complex Traffic Flows

    Science.gov (United States)

    Smith, Jeremy C.; Neitzke, Kurt W.; Bussink, Frank J. L.

    2008-01-01

    This paper presents the results from a study that investigates the performance of aspects of an Airborne Separation Assistance System (ASAS) under varying demand levels using realistic traffic patterns. This study only addresses the tactical aspects of an ASAS using aircraft state data (latitude, longitude, altitude, heading and speed) to detect and resolve projected conflicts. The main focus of this paper is to determine the extent to which sole reliance on the proposed tactical ASAS can maintain aircraft separation at demand levels up to three times current traffic. The effect of mixing ASAS equipped aircraft with non-equipped aircraft that do not have the capability to self-separate is also investigated.

  5. Three-Dimensional Dielectrophoretic Microparticle Separator Fabricated by Ultraviolet-Assisted Direct-Write Assembly.

    Science.gov (United States)

    Dalir, Hamid; Farahani, Rouhollah D; Hernandez, Lewith; Aldebert, Clément; Lévesque, Martin; Therriault, Daniel

    2016-01-01

    The design and fabrication of complex microfluidic devices is a subject of broad biomedical and technological interest. In this paper, we demonstrate the fabrication of a three-dimensional (3D) dielectrophoretic microparticle separator involving ultraviolet (UV)-assisted direct-write assembly of a UV-curable polyurethane. This approach yields a series of 3D microcoil interdigitated electrodes with defined geometry promoting particle separation through dielectrophoresis. These vertical microcoils give rise to considerable improvements in separation relative to standard planar (2D) microelectrodes. We envisage that the complex 3D electrodes will provide an enabling platform for a wide array of fluidic- and electronic-based applications. PMID:27398520

  6. Electric field assisted aerosol assisted chemical vapour deposition of nanostructured metal oxide thin films

    International Nuclear Information System (INIS)

    Nanostructured thin films of tungsten, vanadium and titanium oxides were deposited on gas sensor substrates from the electric field assisted chemical vapour deposition reaction of tungsten hexaphenoxide, vanadyl acetylacetonate and titanium tetraisopropoxide respectively. The electric fields were generated by applying a potential difference between the inter-digitated electrodes of the gas sensor substrates during the deposition. The deposited films were characterised using scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The application of an electric field, encouraged the formation of interesting and unusual nanostructured morphologies, with a change in scale length and island packing. It was also noted that crystallographic orientation of the films could be controlled as a function of electric field type and strength. The gas sensor properties of the films were also examined; it was found that a two to three fold enhancement in the gas response could be observed from sensors with enhanced morphologies compared to control sensors grown without application of an electric field. - Highlights: • Electric field assisted chemical vapour deposition method • Ability to create high surface area film architectures • Can produce enhanced sensor response • Good control over film properties

  7. Electric field assisted aerosol assisted chemical vapour deposition of nanostructured metal oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Naik, Anupriya J.T.; Bowman, Christopher; Panjwani, Naitik [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); Warwick, Michael E.A. [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); UCL Energy Institute, Central House, 14 Upper Woburn Place, London WC1H 0HY (United Kingdom); Binions, Russell, E-mail: r.binions@qmul.ac.uk [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H OAJ (United Kingdom); School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2013-10-01

    Nanostructured thin films of tungsten, vanadium and titanium oxides were deposited on gas sensor substrates from the electric field assisted chemical vapour deposition reaction of tungsten hexaphenoxide, vanadyl acetylacetonate and titanium tetraisopropoxide respectively. The electric fields were generated by applying a potential difference between the inter-digitated electrodes of the gas sensor substrates during the deposition. The deposited films were characterised using scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The application of an electric field, encouraged the formation of interesting and unusual nanostructured morphologies, with a change in scale length and island packing. It was also noted that crystallographic orientation of the films could be controlled as a function of electric field type and strength. The gas sensor properties of the films were also examined; it was found that a two to three fold enhancement in the gas response could be observed from sensors with enhanced morphologies compared to control sensors grown without application of an electric field. - Highlights: • Electric field assisted chemical vapour deposition method • Ability to create high surface area film architectures • Can produce enhanced sensor response • Good control over film properties.

  8. Laser assisted chemically shaped unstable resonator, for high power coherent laser diodes

    International Nuclear Information System (INIS)

    Laser assisted chemical etching (LACE) is used to etch a continuous graded channel, set inside a wide stripe graded-index and separate confinement heterostructure (GRIN-SCH) for laser diodes, grown by metal organic chemical vapor deposition (MOCVD). After a procedure of growing-etching-regrowing, a two-part waveguide is formed inside such modified structure, that is characterized by a negative change in the lateral effective refractive index (ERI). This effects the cavity to work as an unstable resonator. Procedures on the photo etching process are described, including the GaAs photochemistry and the optical system, with special emphasis on the fabrication of the approximately parabolic channels, as this represents a novel step. We call the cavity fabricated by this method, the shaped unstable resonator (SHUR). (Author)

  9. Bulk micromachining of Si by metal-assisted chemical etching.

    Science.gov (United States)

    Kim, Sang-Mi; Khang, Dahl-Young

    2014-09-24

    Bulk micromachining of Si is demonstrated by the well-known metal-assisted chemical etching (MaCE). Si microstructures, having lateral dimension from 5 μm up to millimeters, are successfully sculpted deeply into Si substrate, as deep as >100 μm. The key ingredient of this success is found to be the optimizations of catalyst metal type and its morphology. Combining the respective advantages of Ag and Au in the MaCE as a Ag/Au bilayer configuration leads to quite stable etch reaction upon a prolonged etch duration up to >5 h. Further, the permeable nature of the optimized Ag/Au bilayer metal catalyst enables the etching of pattern features having very large lateral dimension. Problems such as the generation of micro/nanostructures and chemical attacks on the top of pattern surface are successfully overcome by process optimizations such as post-partum sonication treatment and etchant formulation control. The method can also be successful to vertical micromachining of Si substrate having other crystal orientations than Si(100), such as Si(110) and Si(111). The simple, easy, and low-cost nature of present approach may be a great help in bulk micromachining of Si for various applications such as microelectromechanical system (MEMS), micro total analysis system (μTAS), and so forth. PMID:24820931

  10. Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

    International Nuclear Information System (INIS)

    The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

  11. Ultrasonic flexural vibration assisted chemical mechanical polishing for sapphire substrate

    International Nuclear Information System (INIS)

    The sapphire substrates are polished by traditional chemical mechanical polishing (CMP) and ultrasonic flexural vibration (UFV) assisted CMP (UFV-CMP) respectively with different pressures. UFV-CMP combines the functions of traditional CMP and ultrasonic machining (USM) and has special characteristics, which is that ultrasonic vibrations of the rotating polishing head are in both horizontal and vertical directions. The material removal rates (MRRs) and the polished surface morphology of CMP and UFV-CMP are compared. The MRR of UFV-CMP is two times larger than that of traditional CMP. The surface roughness (root mean square, RMS) of the polished sapphire substrate of UFV-CMP is 0.83 A measured by the atomic force microscopy (AFM), which is much better than 2.12 A obtained using the traditional CMP. And the surface flatness of UFV-CMP is 0.12 μm, which is also better than 0.23 μm of the traditional CMP. The results show that UFV-CMP is able to improve the MRR and finished surface quality of the sapphire substrates greatly. The material removal and surface polishing mechanisms of sapphire in UFV-CMP are discussed too.

  12. From SRAFAP to SISAK - rapid chemical separations in nuclear research

    International Nuclear Information System (INIS)

    The author gives an overview of rapid radiochemical separations, starting from the early experiments done by Rutherford up to the very sophisticated recoil fragment separations by fast on-line methods as an attempt to produce superheavy elements. Main emphasis is given to developments during the last decades and the extensive work performed by collaborators of the Nuclear Chemistry Institute at the University of Mainz. (RB)

  13. Membrane-based, sedimentation-assisted plasma separator for point-of-care applications.

    Science.gov (United States)

    Liu, Changchun; Mauk, Michael; Gross, Robert; Bushman, Frederic D; Edelstein, Paul H; Collman, Ronald G; Bau, Haim H

    2013-11-01

    Often, high-sensitivity, point-of-care (POC) clinical tests, such as HIV viral load, require large volumes of plasma. Although centrifuges are ubiquitously used in clinical laboratories to separate plasma from whole blood, centrifugation is generally inappropriate for on-site testing. Suitable alternatives are not readily available to separate the relatively large volumes of plasma from milliliters of blood that may be needed to meet stringent limit-of-detection specifications for low-abundance target molecules. We report on a simple-to-use, low-cost, pump-free, membrane-based, sedimentation-assisted plasma separator capable of separating a relatively large volume of plasma from undiluted whole blood within minutes. This plasma separator consists of an asymmetric, porous, polysulfone membrane housed in a disposable chamber. The separation process takes advantage of both gravitational sedimentation of blood cells and size exclusion-based filtration. The plasma separator demonstrated a "blood in-plasma out" capability, consistently extracting 275 ± 33.5 μL of plasma from 1.8 mL of undiluted whole blood within less than 7 min. The device was used to separate plasma laden with HIV viruses from HIV virus-spiked whole blood with recovery efficiencies of 95.5% ± 3.5%, 88.0% ± 9.5%, and 81.5% ± 12.1% for viral loads of 35,000, 3500, and 350 copies/mL, respectively. The separation process is self-terminating to prevent excessive hemolysis. The HIV-laden plasma was then injected into our custom-made microfluidic chip for nucleic acid testing and was successfully subjected to reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP), demonstrating that the plasma is sufficiently pure to support high-efficiency nucleic acid amplification. PMID:24099566

  14. GaN nanowire arrays by a patterned metal-assisted chemical etching

    Science.gov (United States)

    Wang, K. C.; Yuan, G. D.; Wu, R. W.; Lu, H. X.; Liu, Z. Q.; Wei, T. B.; Wang, J. X.; Li, J. M.; Zhang, W. J.

    2016-04-01

    We developed an one-step and two-step metal-assisted chemical etching method to produce self-organized GaN nanowire arrays. In one-step approach, GaN nanowire arrays are synthesized uniformly on GaN thin film surface. However, in a two-step etching processes, GaN nanowires are formed only in metal uncovered regions, and GaN regions with metal-covering show nano-porous sidewalls. We propose that nanowires and porous nanostructures are tuned by sufficient and limited etch rate, respectively. PL spectra shows a red-shift of band edge emission in GaN nanostructures. The formation mechanism of nanowires was illustrated by two separated electrochemical reactions occur simultaneously. The function of metals and UV light was illustrated by the scheme of potential relationship between energy bands in Si, GaN and standard hydrogen electrode potential of solution and metals.

  15. Tritium separation factors in distillation and chemical exchange processes

    International Nuclear Information System (INIS)

    The vapour pressures of different isotopic hydrogen, water and ammonia molecules have been calculated. These vapour pressures can be used to evaluate relative volatilities of different species for separation of tritium isotopes by distillation. The equilibrium constants for various exchange reactions involving different deuterated and tritiated species of hydrogen, water and ammonia molecules have also been calculated for different temperatures. (author)

  16. Magnetic Separation-Assistant Fluorescence Resonance Energy Transfer Inhibition for Highly Sensitive Probing of Nucleolin.

    Science.gov (United States)

    Li, Yan-Ran; Liu, Qian; Hong, Zhangyong; Wang, He-Fang

    2015-12-15

    For the widely used "off-on" fluorescence (or phosphorescence) resonance energy transfer (FRET or PRET) system, the separation of donors and acceptors species was vital for enhancing the sensitivity. To date, separation of free donors from FRET/PRET inhibition systems was somewhat not convenient, whereas separation of the target-induced far-between acceptors has hardly been reported yet. We presented here a novel magnetic separation-assistant fluorescence resonance energy transfer (MS-FRET) inhibition strategy for highly sensitive detection of nucleolin using Cy5.5-AS1411 as the donor and Fe3O4-polypyrrole core-shell (Fe3O4@PPY) nanoparticles as the NIR quenching acceptor. Due to hydrophobic interaction and π-π stacking of AS1411 and PPY, Cy5.5-AS1411 was bound onto the surface of Fe3O4@PPY, resulting in 90% of fluorescence quenching of Cy5.5-AS1411. Owing to the much stronger specific interaction of AS1411 and nucleolin, the presence of nucleolin could take Cy5.5-AS1411 apart from Fe3O4@PPY and restore the fluorescence of Cy5.5-AS1411. The superparamagnetism of Fe3O4@PPY enabled all separations and fluorescence measurements complete in the same quartz cell, and thus allowed the convenient but accurate comparison of the sensitivity and fluorescence recovery in the cases of separation or nonseparation. Compared to nonseparation FRET inhibition, the separation of free Cy5.5-AS1411 from Cy5.5-AS1411-Fe3O4@PPY solution (the first magnetic separation, MS-1) had as high as 25-fold enhancement of the sensitivity, whereas further separation of the nucleolin-inducing far-between Fe3O4@PPY from the FRET inhibition solution (the second magnetic separation, MS-2) could further enhance the sensitivity to 35-fold. Finally, the MS-FRET inhibition assay displayed the linear range of 0.625-27.5 μg L(-1) (8.1-359 pM) and detection limit of 0.04 μg L(-1) (0.05 pM) of nucleolin. The fluorescence intensity recovery (the percentage ratio of the final restoring fluorescence intensity

  17. Chemical separations schemes for partitioning and transmutation systems

    International Nuclear Information System (INIS)

    In the initial phase of the U.S. Accelerator Transmutation of Waste (ATW) program, a single-tier system was foreseen in which the transuranics and long-lived fission products (specifically, 99Tc and 129I) recovered from spent LWR oxide fuel would be sent directly to an accelerator-driven transmuter reactor [1]. Because the quantity of fuel to be processed annually was so large (almost 1,500 tons per year), an aqueous solvent extraction process was chosen for LWR fuel processing. Without the need to separate transuranics from one another for feed to the transmuter, it became appropriate to develop an advanced aqueous separations method that became known as UREX. The UREX process employs an added reagent (acetohydroxamic acid) that suppresses the extraction of plutonium and promotes the extraction of technetium together with uranium. Technetium can then be efficiently removed from the uranium; the recovered uranium, being highly decontaminated, can be disposed of as a low-level waste or stored in an unshielded facility for future use. Plutonium and the other transuranic elements, plus the remaining fission products, are directed to the liquid waste stream. This stream is calcined, converting the transuranics and fission products to their oxides. The resulting oxide powder, now representing only about four percent of the original mass of the spent fuel, is reduced to metallic form by means of a pyrometallurgical process. Subsequently, the transuranics are separated from the fission products in another pyro-metallurgical step involving molten salt electrorefining

  18. Plasma assisted chemical vapour deposition for optical coatings

    International Nuclear Information System (INIS)

    Full text: Plasma assisted chemical vapour deposition (PECVD) is commonly used in semiconductor fabrication plants for depositing layers of dielectric materials. Reactive gasses are admitted to a chamber at low pressure and applying an electric field, usually a RF field, generates a plasma. The gasses react to form a solid material on the walls of the chamber and substrates. In this project we are exploring the possibility of applying this method to the growth of multilayer optical thin films. A small prototype system was constructed and optical multi layers of up to 24 layers were deposited over a diameter of 90 mm. The system uses 13.56 MHz RF to generate the plasma in a simple capacitive plate chamber. The gasses used were silane, oxygen and nitrogen. This allows SiO2 (RI 1.45) and Si3N4 (RI 1.93) to be deposited. Multilayer coatings were designed using these materials on TFCalc. The required thickness for the various layers were tabulated and fed into a computer controlling the gas flow during deposition. In this way the structures were deposited semi-automatically. The growing films were monitored using a spectrometer looking at light reflected from the growing film over a range from 400 - 800 nm simultaneously. This data was then used to reconstruct the deposition and analyze deviations from the design. An SEM micrograph of the cross-section of the multilayers was used to obtain relative thicknesses of the individual layers. Other structures deposited include rugate notch filters, coloured filters and broad band anti-reflection layers. Running the prototype has proved the concept and the project has moved to a scale up stage in which a larger version is being constructed at Avtronics Pty Ltd. This aims to coat uniformly over a diameter of 600 mm. Initially, the same materials will be used to produce coatings but fixture work will increase the refractive index range of materials which can be deposited and fully automate the coating process. (authors)

  19. New strategies for the chemical separation of actinides and lanthanides

    International Nuclear Information System (INIS)

    A general model is proposed for the effective design of ligands for partitioning. There is no doubt that the correct design of a molecule is required for the effective separation by separation of metal ions such as lanthanides(III) and actinides(III). Heterocyclic ligands with aromatic rings systems have a rich chemistry, which is only now becoming sufficiently well understood, in relation to the partitioning process. The synthesis, characterisation and structures of some chosen molecules will be introduced in order to illustrate some important features. For example, the molecule N-butyl-2-amino-4,6-di (2-pyridyl)-1,3,5-triazine (BADPTZ), which is an effective solvent extraction reagent for actinides and lanthanides, has been synthesised, characterised and its interaction with metal ions studied. The interesting and important features of this molecule will be compared with those of other heterocyclic molecules such as 2,6-bis(5-butyl-1,2,4-triazol-3-yl) pyridine (DBTZP), which is a candidate molecule for the commercial separation of actinides and lanthanide elements. Primary Coordination Sphere. One of the most critical features concerning whether a molecule is a suitable extraction reagent is the nature of the binding and co-ordination in the primary co-ordination sphere. This effect will be considered in depth for the selected heterocylic molecules. It will be shown how the bonding of the heterocyclic and nitrate ligands changes as the complete lanthanide series is traversed from lanthanum to lutetium. For effective solvent extraction, the ligand(s) should be able completely to occupy the primary co-ordination sphere of the metal ion to be extracted. Interactions in the secondary co-ordination sphere are of less importance. Inter-complex Hydrogen Bonding Interactions. Another feature that will be considered is the intermolecular binding between ligands when bound to the metal ion. Thus the intermolecular structures between complex molecules will be considered

  20. Laser-machined components for microanalytical and chemical separation devices

    Science.gov (United States)

    Matson, Dean W.; Martin, Peter M.; Bennett, Wendy D.

    1998-10-01

    Excimer lasers have proven to be powerful tools for machining polymeric components used in microanalytical and microchemical separation devices. We report the use of laser machining methods to produce microfluidic channels and liquid/liquid contact membranes for a number of devices fabricated at our laboratory. Microchannels 50- to 100- micrometers -wide have been produced directly in bulk polycarbonate chips using a direct-write laser micromachining system. Wider microchannels have been produced by laser machining paths through sheets of polyimide film, then sandwiching the patterned piece between solid chips of polycarbonate stock. A comparison of direct-write and mask machining processes used to produce some of the microfluidic features is made. Examples of microanalytical devices produced using these methods are presented. Included are microdialysis units used to remove electrolytes from liquid samples and electrophoretic separation devices, both used for extremely low volume samples intended for mass spectrometric analysis. A multilayered microfluidic device designed to analyze low volume groundwater samples for hazardous metals and a fluidics motherboard are also described. Laser machining processes have also been explored for producing polymeric membranes suitable for use in liquid/liquid contactors used for removal of soluble hazardous components from waste streams. A step-and-repeat mask machining process was used to produce 0.5 X 8 cm membranes in 25- and 50-micrometers -thick polyimide. Pore diameters produced using this method were five and ten micrometers. The laser machined membranes were sputter coated with PTFE prior to use to improve fluid breakthrough characteristics.

  1. Hydrogen-bond interaction assisted branched copolymer HILIC material for separation and N-glycopeptides enrichment.

    Science.gov (United States)

    Shao, Wenya; Liu, Jianxi; Yang, Kaiguang; Liang, Yu; Weng, Yejing; Li, Senwu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-09-01

    Hydrophilic interaction chromatography (HILIC) has attracted increasing attention in recent years due to its efficient application in the separation of polar compounds and the enrichment of glycopeptides. However, HILIC materials are still of weak hydrophilicity and thereby present weak retention and selectivity. In this work, branched copolymer modified hydrophilic material Sil@Poly(THMA-co-MBAAm), with high hydrophilicity and unique "claw-like" polyhydric groups, were prepared by "grafting from" thiol-ene click reaction. Due to the abundant functional groups provided by branched copolymer, the material showed excellent retention for nucleosides, necleobases, acidic compounds, sugars and peptides. Furthermore, Sil@Poly(THMA-co-MBAAm) was also applied for the N-glycosylation sites profiling towards the digests of the mouse brain, and 1997N-glycosylated peptides were identified, corresponding to 686 glycoprotein groups. Due to the assisted hydrogen-bond interaction, the selectivity for glycopeptide enrichment in the real sample reached 94.6%, which was the highest as far as we know. All these results indicated that such hydrogen-bond interaction assisted branched copolymer HILIC material possessed great potential for the separation and large scale glycoproteomics analysis. PMID:27343616

  2. REMOVAL OF ORGANIC CHEMICALS FROM WASTEWATER BY SURFACTANT SEPARATION

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-01-01

    This research presents a novel hybrid process for removing organic chemicals from contaminated water. The process uses surfactant to carry out two unit operations (1) Extraction; (2) Foam flotation. In the first step, surfactant is used to extract most of the amounts of organic contaminants in the stream. In the second step, foam flotation is used to further reduce organic contaminants and recover surfactant from the stream. The process combines the advantages of extraction and foam flotation, which allows the process not only to handle a wide range of organic contaminants, but also to effectively treat a wide range of the concentration of organic contaminants in the stream and reduce it to a very low level. Surfactant regeneration can be done by conventional methods. This process is simple and low cost. The wastes are recoverable. The objective of this research is to develop an environmentally innocuous process for the wastewater or reclaimed water treatment with the ability to handle a wide range of organic contaminants, also to effectively treat a wide range of the concentration of organic contaminants in contaminated water and reduce it to a very low level, finally, provides simpler, less energy cost and economically-practical process design. Another purpose is to promote the environmental concern in minority students and encourage minority students to become more involved in environmental engineering research.

  3. REMOVAL OF ORGANIC CHEMICALS FROM WASTEWATER BY SURFACTANT SEPARATION; FINAL

    International Nuclear Information System (INIS)

    This research presents a novel hybrid process for removing organic chemicals from contaminated water. The process uses surfactant to carry out two unit operations (1) Extraction; (2) Foam flotation. In the first step, surfactant is used to extract most of the amounts of organic contaminants in the stream. In the second step, foam flotation is used to further reduce organic contaminants and recover surfactant from the stream. The process combines the advantages of extraction and foam flotation, which allows the process not only to handle a wide range of organic contaminants, but also to effectively treat a wide range of the concentration of organic contaminants in the stream and reduce it to a very low level. Surfactant regeneration can be done by conventional methods. This process is simple and low cost. The wastes are recoverable. The objective of this research is to develop an environmentally innocuous process for the wastewater or reclaimed water treatment with the ability to handle a wide range of organic contaminants, also to effectively treat a wide range of the concentration of organic contaminants in contaminated water and reduce it to a very low level, finally, provides simpler, less energy cost and economically-practical process design. Another purpose is to promote the environmental concern in minority students and encourage minority students to become more involved in environmental engineering research

  4. Survey of knowledge of hazards of chemicals potentially associated with the advanced isotope separation processes

    International Nuclear Information System (INIS)

    Hazards of chemical potentially associated with the advanced isotope separation processes are estimated based on open literature references. The tentative quantity of each chemical associated with the processes and the toxicity of the chemical are used to estimate this hazard. The chemicals thus estimated to be the most potentially hazardous to health are fluorine, nitric acid, uranium metal, uranium hexafluoride, and uranium dust. The estimated next most hazardous chemicals are bromine, hydrobromic acid, hydrochloric acid, and hydrofluoric acid. For each of these chemicals and for a number of other process-associated chemicals the following information is presented: (1) any applicable standards, recommended standards and their basis; (2) a brief discussion to toxic effects including short exposure tolerance, atmospheric concentration immediately hazardous to life, evaluation of exposures, recommended control procedures, chemical properties, and a list of any toxicology reviews; and (3) recommendations for future research

  5. Economic optimization of heat pump-assisted distillation columns in methanol-water separation

    International Nuclear Information System (INIS)

    Finding efficient alternative to CDiC (Conventional Distillation Column) for methanol-water separation has been an attractive field of study in literature. In this work, five heat pump-assisted schemes are proposed and compared to each other to find the optimal one; (1) VRC (Vapor Recompression Column), (2) external HIDiC (Heat-Integrated Distillation Column), (3) intensified HIDiC with feed preheater, (4) double compressor intensified HIDiC-1, and (5) double compressor intensified HIDiC-2. GA (Genetic Algorithm) is then implemented for optimization of the schemes when TAC (Total Annual Cost) is its objective function. During optimization, two new variables are added for using only appropriate amount of the overhead stream in VRC and double compressor intensified HIDiCs, and another new binary variable is also used for considering feed preheating. Although TAC of the intensified HIDiC with feed preheater is found higher than CDiC by 25.0%, all optimal VRC, external HIDiC, double compressor intensified HIDiCs schemes are reached lower optimal TAC by 3.1%, 27.2%, 24.4%, and 34.2%. Introduced for the first time, the optimal scheme is the double compressor intensified HIDiC-2 with 34.2% TAC saving, 70.4% TEC (Total Energy Consumption) reduction with payback period of 3.30 years. - Highlights: • Study of an industrial distillation unit in methanol-water separation. • Optimization of different heat pump-assisted distillation columns. • Implementation of genetic algorithm during optimization. • Economic and thermodynamic comparisons of optimal results with the industrial case

  6. A Performance Assessment of an Airborne Separation Assistance System Using Realistic Complex Traffic Flows

    Science.gov (United States)

    Smith, Jeremy C.; Bussink, Frank J. L.

    2008-01-01

    This paper presents the results from a study that investigates the performance of a tactical Airborne Separation Assistance System (ASAS) in en route airspace, under varying demand levels, with realistic traffic flows. The ASAS concept studied here allows flight crews of equipped aircraft to perform separation from other air traffic autonomously. This study addresses the tactical aspects of an ASAS using aircraft state data (i.e. position and velocity) to detect and resolve projected conflicts. In addition, use of a conflict prevention system helps ASAS-equipped aircraft avoid maneuvers that may cause new conflicts. ASAS-capable aircraft are equipped with satellite-based navigation and Automatic Dependent Surveillance Broadcast (ADS-B) for transmission and receipt of aircraft state data. In addition to tactical conflict detection and resolution (CD&R), a complete, integrated ASAS is likely to incorporate a strategic CD&R component with a longer look-ahead time, using trajectory intent information. A system-wide traffic flow management (TFM) component, located at the FAA command center helps aircraft to avoid regions of excessive traffic density and complexity. A Traffic Alert and Collision Avoidance System (TCAS), as used today is the system of last resort. This integrated approach avoids sole reliance on the use of the tactical CD&R studied here, but the tactical component remains a critical element of the complete ASAS. The focus of this paper is to determine to what extent the proposed tactical component of ASAS alone can maintain aircraft separation at demand levels up to three times that of current traffic. The study also investigates the effect of mixing ASAS-equipped aircraft with unequipped aircraft (i.e. current day) that do not have the capability to self-separate. Position and velocity data for unequipped aircraft needs to be available to ASASequipped. Most likely, for this future concept, state data would be available from instrument flight rules (IFR

  7. Bioinspired polydopamine particles-assisted construction of superhydrophobic surfaces for oil/water separation.

    Science.gov (United States)

    Shang, Bin; Wang, Yanbing; Peng, Bo; Deng, Ziwei

    2016-11-15

    Frequent oil spillages and industrial discharge of oils/organic solvents have induced severe environmental pollution and ecological damage, and a great cost in energy and finance has been consumed to solve the problems raised. Therefore, it is urgent to develop a surface hydrophobic modification that can be applied to materials with desired properties of high separation efficiency, excellent selectivity and stable performance in extreme conditions during the oil/water separation. Herein, with combined bioinspirations from mussel adhesive protein (polydopamine) and superhydrophobic lotus leaf (hierarchical structures), we develop a general way to superhydrophobically modify various commercial materials, aiming for the selective removal of oils/organic solvents from water. In this procedure, immersing commercial materials (e.g. melamine sponge, stainless steel mesh, nylon netting and cotton cloth) into water/ethanol/ammonia mixtures at a low concentration of dopamine (DA, 2mg/mL) allows a polydopamine (PDA) coating with a tunable roughness appearing on the substrate in one step. This is because DA can self-polymerize and form PDA particles with a catalyst of ammonia, attaching to any surfaces due to abundant catechol and amine groups in PDA, and ultimately, resulting in hierarchical structures. The subsequent decoration with 1H, 1H, 2H, 2H-perfluorodecanethiol features the surface superhydrophobic and superoleophilic. This approach is straightforward and economic, and carried out under a mild, environmental-benign circumstance, with nonspecific substrate demands. In addition, the as-prepared superhydrophobic materials exhibit excellent separation performances including high absorption/separation capacity, excellent selectivity, and extraordinary recyclability for collecting various oils/organic solvents from water. These superhydrophobic materials have also verified to be highly chemical resistant, environment stable and mechanically durable. Therefore, this

  8. Characterization of Physically and Chemically Separated Athabasca Asphaltenes Using Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Amundaraín Hurtado, Jesús Leonardo; Chodakowski, Martin; Long, Bingwen; Shaw, John M. (Alberta)

    2012-02-07

    Athabasca asphaltenes were characterized using small-angle X-ray scattering (SAXS). Two methods were used to separate asphaltenes from the Athabasca bitumen: namely, chemical separation by precipitation with n-pentane and physical separation by nanofiltration using a zirconia membrane with a 20 nm average pore size. The permeate and chemically separated samples were diluted in 1-methylnaphtalene and n-dodecane prior to SAXS measurements. The temperature and asphaltene concentration ranges were 50-310 C and 1-10.4 wt %, respectively. Model-independent analysis of SAXS data provided the radius of gyration and the scattering coefficients. Model-dependent fits provided size distributions for asphaltenes assuming that they are dense and spherical. Model-independent analysis for physically and chemically separated asphaltenes showed significant differences in nominal size and structure, and the temperature dependence of structural properties. The results challenge the merits of using chemically separated asphaltene properties as a basis for asphaltene property prediction in hydrocarbon resources. While the residuals for model-dependent fits are small, the results are inconsistent with the structural parameters obtained from model-independent analysis.

  9. Chemical separation of Mo and W from terrestrial and extraterrestrial samples via anion exchange chromatography.

    Science.gov (United States)

    Nagai, Yuichiro; Yokoyama, Tetsuya

    2014-05-20

    A new two-stage chemical separation method was established using an anion exchange resin, Eichrom 1 × 8, to separate Mo and W from four natural rock samples. First, the distribution coefficients of nine elements (Ti, Fe, Zn, Zr, Nb, Mo, Hf, Ta, and W) under various chemical conditions were determined using HCl, HNO3, and HF. On the basis of the obtained distribution coefficients, a new technique for the two-stage chemical separation of Mo and W, along with the group separation of Ti-Zr-Hf, was developed as follows: 0.4 M HCl-0.5 M HF (major elements), 9 M HCl-0.05 M HF (Ti-Zr-Hf), 9 M HCl-1 M HF (W), and 6 M HNO3-3 M HF (Mo). After the chemical procedure, Nb remaining in the W fraction was separated using 9 M HCl-3 M HF. On the other hand, Nb and Zn remaining in the Mo fraction were removed using 2 M HF and 6 M HCl-0.1 M HF. The performance of this technique was evaluated by separating these elements from two terrestrial and two extraterrestrial samples. The recovery yields for Mo, W, Zr, and Hf were nearly 100% for all of the examined samples. The total contents of the Zr, Hf, W, and Mo in the blanks used for the chemical separation procedure were 582, 9, 29, and 396 pg, respectively. Therefore, our new separation technique can be widely used in various fields of geochemistry, cosmochemistry, and environmental sciences and particularly for multi-isotope analysis of these elements from a single sample with significant internal isotope heterogeneities. PMID:24801276

  10. Computer assisted optimization of liquid chromatographic separations of small molecules using mixed-mode stationary phases.

    Science.gov (United States)

    Ordoñez, Edgar Y; Benito Quintana, José; Rodil, Rosario; Cela, Rafael

    2012-05-18

    Mixed-mode stationary phases are gaining adepts in liquid chromatography (LC) as more and more applications are published and new commercial columns appear in the market ought to their ability to retain and separate analytes with multiple functionalities. The increased number of adjustable variables gives these columns an enhanced value for the chromatographer, but, on the other hand, it complicates the process of developing satisfactory separations when complex samples must be analyzed. Thus, the availability of computer assisted methods development (CAMD) tools is highly desirable in this field. Therefore, the first specific tool for the CAMD of LC separations in mixed-mode columns is presented. The tool consists in two processes. The first one develops a retention model for peaks in a predefined experimental domain of pH and buffer concentration. In this domain, the retention as a function of the proportion of organic modifier is modeled using a two-stage re-calibration process departing from isocratic retention data and then, from gradient elutions. With this two-stage approach, reliability is gained. In the second process, the model is finally interpolated and used for the unattended optimization of the different possible elution modes available in these columns. This optimization process is driven by an evolutionary algorithm. The development and application of this new chemometrics tool is demonstrated by the optimization of a mixture of neutral and ionizable compounds. Hence, several different types of gradients were generated, showing a good agreement between simulated and experimental data, with retention time errors lower than 5% in most cases. On the other hand, classical CAMD tools, such as design of experiments, were unable to efficiently deal with mixed-mode optimizations, rendering errors above 30% for several compounds. PMID:22494641

  11. Suspension column for recovery and separation of substances using ultrasound-assisted retention of bead sorbents.

    Science.gov (United States)

    Spivakov, Boris Ya; Shkinev, Valeriy M; Danilova, Tatiana V; Knyazkov, Nikolai N; Kurochkin, Vladimir E; Karandashev, Vasiliy K

    2012-12-15

    A novel approach to sorption recovery and separation of different substances is proposed which is based on the use of suspended bead sorbents instead of conventional packed beds of such sorbents. This makes it possible to employ small-sized beads which are trapped in a low-pressure column due to ultrasound-assisted retention, without any frits to hold the sorption material. A flow system including a separation mini-column, named herein a suspension column, has been developed and tested by the studies of solid phase extraction (SPE) of trace metals from bi-distilled water and sea water using a 150-μL column with a silica-based sorbent containing iminodiacetic groups (DIAPAK IDA) and having a grain size of 6 μm. The adsorption properties of DIAPAK IDA suspension (9.5mg) were evaluated through adsorption/desorption experiments, where the effect of solution pH and eluent on the SPE of trace metals were examined by ICP-MS or ICP-AES measurements. When sample solution was adjusted to pH 8.0 and 1 mol L(-1) nitric acid was used as eluent, very good recoveries of more than 90% were obtained for a number of elements in a single-step extraction. To demonstrate the versatility of the approach proposed and to show another advantage of ultrasonic field (acceleration of sorbate/sorbent interaction), a similar system was used for heterogeneous immunoassays of some antigens in ultrasonic field using agarose sorbents modified by corresponding antibodies. It has been shown that immunoglobulins, chlamidia, and brucellos bacteria can be quantitatively adsorbed on 15-μm sorbent (15 particles in 50 μL) and directly determined in a 50-μL mini-chamber using fluorescence detection. PMID:23182579

  12. Inspired superhydrophobic surfaces by a double-metal-assisted chemical etching route

    International Nuclear Information System (INIS)

    Graphical abstract: A double-metal-assisted chemical etching method is employed to fabricate superhydrophobic surfaces, showing a good superhydrophobicity with the contact angle of about 170°, and the sliding angle of about 0°. Meanwhile, the potential formation mechanism about it is also presented. Highlights: ► A double-metal-assisted chemical etching method is employed to fabricate superhydrophobic surfaces. ► The obtained surfaces show good superhydrophobicity with a high contact angle and low sliding angle. ► The color of the etched substrate dark brown or black and it is so-called black silicon. -- Abstract: Silicon substrates treated by metal-assisted chemical etching have been studied for many years since they could be employed in a variety of electronic and optical devices such as integrated circuits, photovoltaics, sensors and detectors. However, to the best of our knowledge, the chemical etching treatment on the same silicon substrate with the assistance of two or more kinds of metals has not been reported. In this paper, we mainly focus on the etching time and finally obtain a series of superhydrophobic silicon surfaces with novel etching structures through two successive etching processes of Cu-assisted and Ag-assisted chemical etching. It is shown that large-scale homogeneous but locally irregular wire-like structures are obtained, and the superhydrophobic surfaces with low hysteresis are prepared after the modifications with low surface energy materials. It is worth noting that the final silicon substrates not only possess high static contact angle and low hysteresis angle, but also show a black color, indicating that the superhydrophobic silicon substrate has an extremely low reflectance in a certain range of wavelengths. In our future work, we will go a step further to discuss the effect of temperature, the size of Cu nanoparticles and solution concentration on the final topography and superhydrophobicity.

  13. Solvent-assisted dewetting during chemical vapor deposition.

    Science.gov (United States)

    Chen, Xichong; Anthamatten, Mitchell

    2009-10-01

    This study examines the use of a nonreactive solvent vapor, tert-butanol, during initiated chemical vapor deposition (iCVD) to promote polymer film dewetting. iCVD is a solventless technique to grow polymer thin films directly from gas phase feeds. Using a custom-built axisymmetric hot-zone reactor, smooth poly(methyl methacrylate) films are grown from methyl methacrylate (MMA) and tert-butyl peroxide (TBPO). When solvent vapor is used, nonequilibrium dewetted structures comprising of randomly distributed polymer droplets are observed. The length scale of observed topographies, determined using power spectral density (PSD) analysis, ranges from 5 to 100 microm and is influenced by deposition conditions, especially the carrier gas and solvent vapor flow rates. The use of a carrier gas leads to faster deposition rates and suppresses thin film dewetting. The use of solvent vapor promotes dewetting and leads to larger length scales of the dewetted features. Control over lateral length scale is demonstrated by preparation of hierarchal "bump on bump" topographies. Vapor-induced dewetting is demonstrated on silicon wafer substrate with a native oxide layer and also on hydrophobically modified substrate prepared using silane coupling. Autophobic dewetting of PMMA from SiOx/Si during iCVD is attributed to a thin film instability driven by both long-range van der Waals forces and short-range polar interactions. PMID:19670895

  14. Review on advanced of solar assisted chemical heat pump dryer for agriculture produce

    International Nuclear Information System (INIS)

    Over the past three decades there has been nearly exponential growth in drying R and D on a global scale. Improving of the drying operation to save energy, improve product quality as well as reduce environmental effect remained as the main objectives of any development of drying system. A solar assisted chemical heat pump dryer is a new solar drying system, which have contributed to better cost-effectiveness and better quality dried products as well as saving energy. A solar collector is adapted to provide thermal energy in a reactor so a chemical reaction can take place. This reduces the dependency of the drying technology on fossil energy for heating. In this paper a review on advanced of solar assisted chemical heat pump dryer is presented (the system model and the results from experimental studies on the system performance are discussed). The review of heat pump dryers and solar assisted heat pump dryer is presented. Description of chemical heat pump types and the overview of chemical heat pump dryer are discussed. The combination of chemical heat pump and solar technology gives extra efficiency in utilizing energy. (author)

  15. Review on advanced of solar assisted chemical heat pump dryer for agriculture produce

    Energy Technology Data Exchange (ETDEWEB)

    Fadhel, M.I. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, 75450 Melaka (Malaysia); Sopian, K.; Daud, W.R.W.; Alghoul, M.A. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2011-02-15

    Over the past three decades there has been nearly exponential growth in drying R and D on a global scale. Improving of the drying operation to save energy, improve product quality as well as reduce environmental effect remained as the main objectives of any development of drying system. A solar assisted chemical heat pump dryer is a new solar drying system, which have contributed to better cost-effectiveness and better quality dried products as well as saving energy. A solar collector is adapted to provide thermal energy in a reactor so a chemical reaction can take place. This reduces the dependency of the drying technology on fossil energy for heating. In this paper a review on advanced of solar assisted chemical heat pump dryer is presented (the system model and the results from experimental studies on the system performance are discussed). The review of heat pump dryers and solar assisted heat pump dryer is presented. Description of chemical heat pump types and the overview of chemical heat pump dryer are discussed. The combination of chemical heat pump and solar technology gives extra efficiency in utilizing energy. (author)

  16. Chemical ordering suppresses large-scale electronic phase separation in doped manganites

    Science.gov (United States)

    Zhu, Yinyan; Du, Kai; Niu, Jiebin; Lin, Lingfang; Wei, Wengang; Liu, Hao; Lin, Hanxuan; Zhang, Kai; Yang, Tieying; Kou, Yunfang; Shao, Jian; Gao, Xingyu; Xu, Xiaoshan; Wu, Xiaoshan; Dong, Shuai; Yin, Lifeng; Shen, Jian

    2016-04-01

    For strongly correlated oxides, it has been a long-standing issue regarding the role of the chemical ordering of the dopants on the physical properties. Here, using unit cell by unit cell superlattice growth technique, we determine the role of chemical ordering of the Pr dopant in a colossal magnetoresistant (La1-yPry)1-xCaxMnO3 (LPCMO) system, which has been well known for its large length-scale electronic phase separation phenomena. Our experimental results show that the chemical ordering of Pr leads to marked reduction of the length scale of electronic phase separations. Moreover, compared with the conventional Pr-disordered LPCMO system, the Pr-ordered LPCMO system has a metal-insulator transition that is ~100 K higher because the ferromagnetic metallic phase is more dominant at all temperatures below the Curie temperature.

  17. Examination of lignocellulosic fibers for chemical, thermal, and separations properties: Addressing thermo-chemical stability issues

    Science.gov (United States)

    Johnson, Carter David

    Natural fiber-plastic composites incorporate thermoplastic resins with fibrous plant-based materials, sometimes referred to as biomass. Pine wood mill waste has been the traditional source of natural fibrous feedstock. In anticipation of a waste wood shortage other fibrous biomass materials are being investigated as potential supplements or replacements. Perennial grasses, agricultural wastes, and woody biomass are among the potential source materials. As these feedstocks share the basic chemical building blocks; cellulose, hemicellulose, and lignin, they are collectively called lignocellulosics. Initial investigation of a number of lignocellulosic materials, applied to fiber-plastic composite processing and material testing, resulted in varied results, particularly response to processing conditions. Less thermally stable lignocellulosic filler materials were physically changed in observable ways: darkened color and odor. The effect of biomass materials' chemical composition on thermal stability was investigated an experiment involving determination of the chemical composition of seven lignocellulosics: corn hull, corn stover, fescue, pine, soy hull, soy stover, and switchgrass. These materials were also evaluated for thermal stability by thermogravimetric analysis. The results of these determinations indicated that both chemical composition and pretreatment of lignocellulosic materials can have an effect on their thermal stability. A second study was performed to investigate what effect different pretreatment systems have on hybrid poplar, pine, and switchgrass. These materials were treated with hot water, ethanol, and a 2:1 benzene/ethanol mixture for extraction times of: 1, 3, 6, 12, and 24 hours. This factorial experiment demonstrated that both extraction time and medium have an effect on the weight percent of extractives removed from all three material types. The extracted materials generated in the above study were then subjected to an evaluation of thermal

  18. Separation of selected stable isotopes by liquid-phase thermal diffusion and by chemical exchange

    International Nuclear Information System (INIS)

    Useful applications of enriched stable nuclides are unduly restricted by high cost and limited availability. Recent research on liquid phase thermal diffusion (LTD) has resulted in practical processes for separating 34S, 35Cl, and 37Cl in significant quantities (100 to 500 g/yr) at costs much lower than those associated with the electromagnetic (Calutron) process. The separation of the isotopes of bromine by LTD is now in progress and 79Br is being produced in relatively simple equivalent at a rate on the order of 0.5 g/day. The results of recent measurements show that the isotopes of Zn can be separated by LTD of zinc alkyls. The isotopes of calcium can be separated by LTD and by chemical exchange. The LTD process is based on the use of aqueous Ca(NO3)2 as a working fluid. The chemical exchange method involves isotopically selective exchange between an aqueous phase containing a calcium salt and an organic phase containing calcium in the form of a complex with a macrocyclic ligand. The LTD method is suitable for high enrichments at low through-puts; whereas, the chemical exchange techniques is appropriate for lower enrichments at much higher production rates. Current research is directed toward reducing these concepts to practical processes

  19. Chemical recycling of inorganic wastes by using phase separation of glass

    OpenAIRE

    Nanba, Tokuro; Mikami, Shuhei; Imaoka, Takuya; Sakida, Shinichi; Miura, Yoshinari

    2008-01-01

    A chemical recycling process using phase separation of glass was applied to a granulated blast furnace slag with high CaO content. Glasses were prepared by adding B(2)O(3) to the slag in order to promote phase separation, and the glasses were heat-treated above glass transition temperature. In the subsequent acid-treatment, however, gelation due to the elution of SiO(2) phase containing CaO occurred, not obtaining high SiO(2) solids. Then, pretreatment was introduced to reduce CaO content in ...

  20. Noninvasive Temperature Mapping With MRI Using Chemical Shift Water-Fat Separation

    OpenAIRE

    Soher, Brian J.; Wyatt, Cory; Reeder, Scott B.; MacFall, James R.

    2010-01-01

    Tissues containing both water and lipids, e.g., breast, confound standard MR proton reference frequency-shift methods for mapping temperatures due to the lack of temperature-induced frequency shift in lipid protons. Generalized Dixon chemical shift–based water-fat separation methods, such as GE’s iterative decomposition of water and fat with echo asymmetry and least-squares estimation method, can result in complex water and fat images. Once separated, the phase change over time of the water s...

  1. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Medin, Zach [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Cumming, Andrew, E-mail: zmedin@lanl.gov, E-mail: cumming@physics.mcgill.ca [Department of Physics, McGill University, 3600 rue University, Montreal, QC H3A 2T8 (Canada)

    2014-03-01

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  2. Molecular dynamics study of phase separation in fluids with chemical reactions

    Science.gov (United States)

    Krishnan, Raishma; Puri, Sanjay

    2015-11-01

    We present results from the first d =3 molecular dynamics (MD) study of phase-separating fluid mixtures (AB) with simple chemical reactions (A ⇌B ). We focus on the case where the rates of forward and backward reactions are equal. The chemical reactions compete with segregation, and the coarsening system settles into a steady-state mesoscale morphology. However, hydrodynamic effects destroy the lamellar morphology which characterizes the diffusive case. This has important consequences for the phase-separating structure, which we study in detail. In particular, the equilibrium length scale (ℓeq) in the steady state suggests a power-law dependence on the reaction rate ɛ :ℓeq˜ɛ-θ with θ ≃1.0 .

  3. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    International Nuclear Information System (INIS)

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma

  4. A signature of chemical separation in the cooling curves of transiently accreting neutron stars

    CERN Document Server

    Medin, Zach

    2013-01-01

    We show that convection driven by chemical separation can significantly affect the cooling curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  5. Separation of chemically similar elements such as trivalent actinides and lanthanides

    International Nuclear Information System (INIS)

    Separation of chemical elements has been during all times an interesting topic and references may be found from ∼ 3000 B.C., i.e. ion exchange for purification of drinking water. With increasing knowledge the separation methods have become more and more refined. There are many methods used for the separation processes, e.g. pyrometallurgy, chromatographic methods, ion exchange and solvent extraction. Of these the solvent extraction technique is widely used today due to its relative simplicity to scale up and use industrially. The solvent extraction processes have been successfully used during the last 100 years in various areas ranging from the mining industry to the reprocessing of spent nuclear fuel. In some cases the elements that are to be separated have quite different chemical properties and a relatively simple process can be used. In the case of separation of trivalent metal ions with similar properties such as trivalent actinides and lanthanides the problem is more difficult. The separation of actinides and lanthanides is an important question when considering future alternatives to take care of waste from reprocessing of spent nuclear fuel (in for instance a transmutation process). To decrease process losses to secondary waste streams it has been decided that only extracting agents containing carbon, hydrogen, oxygen and nitrogen are to be used, which further increases the difficulty level. Two examples of such ligands are 2,2': 6' ,2-terpyridine and 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine. It has been shown that using such ligands, good separation of actinides and lanthanides can be achieved. This is mainly because nitrogen binds more strongly to actinides than to lanthanides due to the more covalent nature of the bond. Often synergistic extraction is used, adding the reagent to e,g. a 2-bromodecanoic acid extraction system in order to increase the extraction and the separation efficiency. In addition it is also possible to separate different

  6. Microwave-irradiation-assisted hybrid chemical approach for titanium dioxide nanoparticle synthesis: microbial and cytotoxicological evaluation.

    Science.gov (United States)

    Ranjan, Shivendu; Dasgupta, Nandita; Rajendran, Bhavapriya; Avadhani, Ganesh S; Ramalingam, Chidambaram; Kumar, Ashutosh

    2016-06-01

    Titanium dioxide nanoparticles (TNPs) are widely used in the pharmaceutical and cosmetics industries. It is used for protection against UV exposure due to its light-scattering properties and high refractive index. Though TNPs are increasingly used, the synthesis of TNPs is tedious and time consuming; therefore, in the present study, microwave-assisted hybrid chemical approach was used for TNP synthesis. In the present study, we demonstrated that TNPs can be synthesized only in 2.5 h; however, the commonly used chemical approach using muffle furnace takes 5 h. The activity of TNP depends on the synthetic protocol; therefore, the present study also determined the effect of microwave-assisted hybrid chemical approach synthetic protocol on microbial and cytotoxicity. The results showed that TNP has the best antibacterial activity in decreasing order from Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. The IC50 values of TNP for HCT116 and A549 were found to be 6.43 and 6.04 ppm, respectively. Cell death was also confirmed from trypan blue exclusion assay and membrane integrity loss was observed. Therefore, the study determines that the microwave-assisted hybrid chemical approach is time-saving; hence, this technique can be upgraded from lab scale to industrial scale via pilot plant scale. Moreover, it is necessary to find the mechanism of action at the molecular level to establish the reason for greater bacterial and cytotoxicological toxicity. Graphical abstract A graphical representation of TNP synthesis. PMID:26976013

  7. Process boundaries of irreversible scCO2 -assisted phase separation in biphasic whole-cell biocatalysis.

    Science.gov (United States)

    Brandenbusch, Christoph; Glonke, Sebastian; Collins, Jonathan; Hoffrogge, Raimund; Grunwald, Klaudia; Bühler, Bruno; Schmid, Andreas; Sadowski, Gabriele

    2015-11-01

    The formation of stable emulsions in biphasic biotransformations catalyzed by microbial cells turned out to be a major hurdle for industrial implementation. Recently, a cost-effective and efficient downstream processing approach, using supercritical carbon dioxide (scCO2 ) for both irreversible emulsion destabilization (enabling complete phase separation within minutes of emulsion treatment) and product purification via extraction has been proposed by Brandenbusch et al. (2010). One of the key factors for a further development and scale-up of the approach is the understanding of the mechanism underlying scCO2 -assisted phase separation. A systematic approach was applied within this work to investigate the various factors influencing phase separation during scCO2 treatment (that is pressure, exposure of the cells to CO2 , and changes of cell surface properties). It was shown that cell toxification and cell disrupture are not responsible for emulsion destabilization. Proteins from the aqueous phase partially adsorb to cells present at the aqueous-organic interface, causing hydrophobic cell surface characteristics, and thus contribute to emulsion stabilization. By investigating the change in cell-surface hydrophobicity of these cells during CO2 treatment, it was found that a combination of catastrophic phase inversion and desorption of proteins from the cell surface is responsible for irreversible scCO2 mediated phase separation. These findings are essential for the definition of process windows for scCO2 -assisted phase separation in biphasic whole-cell biocatalysis. PMID:26012371

  8. Separation and sampling technique of light element isotopes by chemical exchange process

    International Nuclear Information System (INIS)

    Lithium and boron isotope separation technique were studied. Granulation of lithium isotope separation agent was carried out by cure covering in solution. Separation of lithium isotope was stepped up by ammonium carbonate used as elusion agent. Styrene and ester resin derived three kinds of agents such as 2-amino-1, 3-propanediol (1, 3-PD), 2-amino-2-methyl-1, 3-propanediol (Me-1,3-PD) and tris(2-hydroxyethyl)amine (Tris) were used as absorbent.The ester resin with Tris showed larger amount of adsorption (1.4 mmol/g) than other resins. However, all resins with agent indicated more large adsorption volume of boron than the objective value (0.5 mmol/g). Large isotope shift was shown by the unsymmetrical vibration mode of lithium ion on the basis of quantum chemical calculation of isotope effect on dehydration of hydrated lithium ion. (S.Y.)

  9. Comparison of some physico-chemical properties of irradiated cereal starches, separated or contained in flour

    International Nuclear Information System (INIS)

    In this study some physico-chemical properties of separated wheat starch from flour type 500 and 850, rye starch from flour type 720 and triticale starch from flour type 680 were compared. All starches were irradiated with medium doses of gamma rays: 2,3 and 5 kGy directly (after their separation from flour) and in flour. The water binding capacity of starches, their solubility in water and reduction capacity were found to depend on the dose applied and the method of irradiation, individually for each starch. Additional direct irradiation of all starches caused a smaller decrease in the viscosity of starch pastes and a stronger inhibition of the retrogradation process, in comparison to the starches separated from the irradiated flours. (author)

  10. Chemical separation and AES determination of rare earths in thorium oxide

    International Nuclear Information System (INIS)

    A chemical separation method has been developed for the separation of rare earths like, Ce, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and La, Y from ThO2 matrix and their determination by emission spectrographic method. Cyanex-272 ie. [bis(2,4,4-trimethyl pentyl) phosphinic acid] /xylene/ HNO3 extraction system has been used for separation of thorium. The recovery of rare earths as determined by emission spectrographic method was found to be quantitative within experimental error. The estimation range for the analytes lie between 0.02μg-4μg based on 100 mg ThO2. (author). 3 refs., 1 tab

  11. Mound Laboratory activities in chemical and physical research: July--December 1976. [Isotope separation; metal hydride research, separation chemistry and separation research

    Energy Technology Data Exchange (ETDEWEB)

    1977-05-04

    The status of the following programs is reported: isotope separation of carbon, argon, helium, krypton, neon, xenon, oxygen, and sulfur; metal hydride research; separation chemistry; and separation research. (LK)

  12. Electron Cyclotron Resonance Based Chemically Assisted Plasma Etching Of Silicon in CF4/Ar Plasma

    Science.gov (United States)

    Bhardwaj, R. K.; Angra, S. K.; Bajpai, R. P.; Lal, Madan; Bharadwaj, Lalit M.

    2005-09-01

    Etching of silicon in Chemical Assisted Plasma Etching mode with CF4 gas being sprayed on the surface of wafer in process chamber and Ar fed to ECR cavity in Electron Cyclotron Resonance (ECR) source was carried out. The plasma source was 2.45 GHz microwave source superimposed with mirror type magnetic field configuration to have resonance. Effect of CF4/Ar ratio and substrate bias on etching rate of silicon and anisotropy of etched profile has been investigated. The variation of etch rate and anisotropy has been correlated to the availability of fluorine atoms and other radicals available for etching. Optimum parameters required for etching of silicon in chemical assisted plasma etching with self-assembled ECR plasma source has been established.

  13. Electron Cyclotron Resonance Based Chemically Assisted Plasma Etching Of Silicon in CF4/Ar Plasma

    International Nuclear Information System (INIS)

    Etching of silicon in Chemical Assisted Plasma Etching mode with CF4 gas being sprayed on the surface of wafer in process chamber and Ar fed to ECR cavity in Electron Cyclotron Resonance (ECR) source was carried out. The plasma source was 2.45 GHz microwave source superimposed with mirror type magnetic field configuration to have resonance. Effect of CF4/Ar ratio and substrate bias on etching rate of silicon and anisotropy of etched profile has been investigated. The variation of etch rate and anisotropy has been correlated to the availability of fluorine atoms and other radicals available for etching. Optimum parameters required for etching of silicon in chemical assisted plasma etching with self-assembled ECR plasma source has been established

  14. Computer-controlled, chemical separation system for use with neutron-activated samples

    International Nuclear Information System (INIS)

    Neutron activation analysis has proven to be a sensitive technique for the quantitative determination of metals in the parts-per-billion range. While sodium and potassium salt concentrations in sea water and biological materials are on the order of 10,000 ppm, the levels of trace metals range from 1 ppm to 0.1 ppb. The high concentrations and high activities of the salts in these matrices greatly reduce the ability to measure short half-life isotopes such as 2.3 min. 28Al, 3.8 min. 52V and 5.1 min. 66Cu. Post-irradiation separation is often the method of choice for such samples. However, when performed manually this technique is awkward, slow and unsafe. The Basic Automated Separation System (BASS) is a computer-controlled, chemical separation system for use in post-irradiation separations of neutron activated samples. It allows irradiation and separation of high-activated samples without user-intervention

  15. Microwave-Assisted Reaction in Green Solvents Recycles PHB to Functional Chemicals

    OpenAIRE

    Yang, Xi; Odelius, Karin; Hakkarainen, Minna

    2014-01-01

    An efficient microwave-assisted process for chemical recycling of poly(3-hydroxybutyrate) (PHB) in green solvents was demonstrated. Previously, PHB has been thermally recycled to crotonic acid and unsaturated oligomers. Our aim was to utilize green solvents (water, methanol, and ethanol) under alkaline conditions to achieve fast hydrolysis and monomeric or oligomeric degradation products with carboxyl and hydroxyl or methoxy or ethoxy end groups. Preliminary screening confirmed that the most ...

  16. Laser-assisted chemical liquid-phase deposition of metals for micro- and optoelectronics

    OpenAIRE

    Kordás, K. (Krisztián)

    2002-01-01

    Abstract The demands toward the development of simple and cost-effective fabrication methods of metallic structures with high lateral resolution on different substrates - applied in many fields of technology, such as in microelectronics, optoelectronics, micromechanics as well as in sensor and actuator applications - gave the idea to perform this research. Due to its simplicity, laser-assisted chemical liquid-phase deposition (LCLD) has been investigated and applied for the metallization o...

  17. High performance separation of xylose and glucose by enzyme assisted nanofiltration

    DEFF Research Database (Denmark)

    Morthensen, Sofie Thage; Luo, Jianquan; Meyer, Anne S.;

    2015-01-01

    An integrated membrane system was investigated for the separation of mixtures of xylose and glucose. Separation of these sugars is extremely challenging due to their similar structure, size and charge. In order to enhance the xylose separation factor in nanofiltration (NF), we present an enzymatic...... process for converting glucose to gluconic acid followed by separation of xylose from gluconic acid by nanofiltration. Process conditions which favored the negative charge repulsions between gluconic acid and the NF270 membrane were examined. At the best conditions (9:1 feed molar ratio of xylose to...

  18. Chemical separations technologies for the US accelerator transmutation of waste programme

    International Nuclear Information System (INIS)

    Management of the spent nuclear fuel generated by the operating commercial reactors in the United States is entering a new phase because it is clear that the continued rate of accumulation of spent fuel is such that the spent fuel inventory will soon exceed the legislated capacity of the proposed Yucca Mountain repository. An integrated chemical separations system has been conceived for the partitioning of this fuel preparatory to transmutation of transuranic elements and long-lived fission products in an accelerator-driven transmuter reactor. A hybrid aqueous/pyrochemical separations system is being developed, with the initial separation done with an aqueous solvent extraction process called UREX. The UREX process extracts uranium, technetium and iodine and directs the transuranic elements and other fission products to the liquid waste stream. The uranium is sufficiently pure that it can be disposed as a low-level waste, while the technetium and iodine are converted into targets for transmutation to stable isotopes. The liquid waste stream containing the transuranics is converted to solid oxide form and the transuranics are separated from the fission products by electrorefining after having been converted to the metallic state. Demonstrations of the process with actual LWR spent fuel are in progress. (author)

  19. Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Charles; Beery, Kyle; Orth, Rick; Zacher, Alan

    2007-09-28

    The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50% of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.

  20. Deposition of air-borne 238Pu near a chemical separation facility

    International Nuclear Information System (INIS)

    Three methods were compared to measure deposition of 238Pu released from a chemical separation facility at the Savannah River Plant, Aiken, SC. The following methods were used: adhesive paper; a collector of rain and dryfall; and soil samples. Excellent agreement among the three methods was found. The measured deposition for the particular source term and meteorological conditions at the Savannah River Plant is described by y proportional to x/sup -1.36/ where y is the pCi of 238Pu deposited per square meter per mC: 238Pu released, and x is distance in meters from the source

  1. Computer Aided Methods & Tools for Separation & Purification of Fine Chemical & Pharmaceutical Products

    DEFF Research Database (Denmark)

    Afonso, Maria B.C.; Soni, Vipasha; Mitkowski, Piotr Tomasz;

    2006-01-01

    An integrated approach that is particularly suitable for solving problems related to product-process design from the fine chemicals, agrochemicals, food and pharmaceutical industries is presented together with the corresponding methods and tools, which forms the basis for an integrated computer...... aided system. The methods and tools are linked through the problems they are able to solve and the associated data-flow. The integrated computer aided system has been used to solve a number of industrial problems and summarized results from a selection, involving separation and purification issues, are...

  2. A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations

    Energy Technology Data Exchange (ETDEWEB)

    Way, J Douglas

    2011-01-21

    This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

  3. Chemical Interactions and Their Role in the Microphase Separation of Block Copolymer Thin Films

    Directory of Open Access Journals (Sweden)

    Richard A. Farrell

    2009-08-01

    Full Text Available The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP systems. BCP systems self-assemble via a thermodynamic driven process where chemical dis-affinity between the blocks driving them part is balanced by a restorative force deriving from the chemical bond between the blocks. These systems are attracting much interest because of their possible role in nanoelectronic fabrication. This form of self-assembly can obtain highly regular nanopatterns in certain circumstances where the orientation and alignment of chemically distinct blocks can be guided through molecular interactions between the polymer and the surrounding interfaces. However, for this to be possible, great care must be taken to properly engineer the interactions between the surfaces and the polymer blocks. The optimum methods of structure directing are chemical pre-patterning (defining regions on the substrate of different chemistry and graphoepitaxy (topographical alignment but both centre on generating alignment through favourable chemical interactions. As in all self-assembling systems, the problems of defect formation must be considered and the origin of defects in these systems is explored. It is argued that in these nanostructures equilibrium defects are relatively few and largely originate from kinetic effects arising during film growth. Many defects also arise from the confinement of the systems when they are ‘directed’ by topography. The potential applications of these materials in electronics are discussed.

  4. Chemical Interactions and Their Role in the Microphase Separation of Block Copolymer Thin Films

    Science.gov (United States)

    Farrell, Richard A.; Fitzgerald, Thomas G.; Borah, Dipu; Holmes, Justin D.; Morris, Michael A.

    2009-01-01

    The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP) systems. BCP systems self-assemble via a thermodynamic driven process where chemical dis-affinity between the blocks driving them part is balanced by a restorative force deriving from the chemical bond between the blocks. These systems are attracting much interest because of their possible role in nanoelectronic fabrication. This form of self-assembly can obtain highly regular nanopatterns in certain circumstances where the orientation and alignment of chemically distinct blocks can be guided through molecular interactions between the polymer and the surrounding interfaces. However, for this to be possible, great care must be taken to properly engineer the interactions between the surfaces and the polymer blocks. The optimum methods of structure directing are chemical pre-patterning (defining regions on the substrate of different chemistry) and graphoepitaxy (topographical alignment) but both centre on generating alignment through favourable chemical interactions. As in all self-assembling systems, the problems of defect formation must be considered and the origin of defects in these systems is explored. It is argued that in these nanostructures equilibrium defects are relatively few and largely originate from kinetic effects arising during film growth. Many defects also arise from the confinement of the systems when they are ‘directed’ by topography. The potential applications of these materials in electronics are discussed. PMID:19865513

  5. Membrane-based, sedimentation-assisted plasma separator for point-of-care applications

    OpenAIRE

    Liu, Changchun; Mauk, Michael; Gross, Robert; Bushman, Frederic D.; Edelstein, Paul H.; Collman, Ronald G.; Bau, Haim H

    2013-01-01

    Often, high sensitivity, point of care, clinical tests, such as HIV viral load, require large volumes of plasma. Although centrifuges are ubiquitously used in clinical laboratories to separate plasma from whole blood, centrifugation is generally inappropriate for on-site testing. Suitable alternatives are not readily available to separate the relatively large volumes of plasma from milliliters of blood that may be needed to meet stringent limit-of-detection specifications for low abundance ta...

  6. 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.

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

    International Nuclear Information System (INIS)

    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

  8. Microwave-assisted synthesis of titania coating onto polymeric separators for improved lithium-ion battery performance

    Science.gov (United States)

    Juang, Ruey-Shin; Hsieh, Chien-Te; Chen, Po-An; Chen, Yu-Fu

    2015-07-01

    This study adopts an efficient microwave-assisted method to deposit TiO2 into tri-layered polymeric membranes, forming composite separators for Li-ion batteries (LIBs) consisted of Li4Ti5O12 (LTO) anode/Li cathode. The microwave deposition is capable of growing TiO2 crystals into the porous membranes at 40 °C in a short period of ∼8 min. Both improved thermal and dimensional stability are achieved by the deposition of TiO2 in the separators. The improvement can be attributed to the formation of robust skeleton to stabilize the separators, imparting a superior insulation and mass transport barrier against volatile compounds formed during the thermal decomposition process. After depositing an appropriate amount of TiO2, the TiO2-coated separator still features well-developed porous structure, allowing favorable liquid wettability and high mass uptake of electrolyte. The amount of TiO2 deposits plays as a crucial role in facilitating the cell performance, including high ionic conductivity, low inner resistance, high operation temperature, high energy density, and excellent cycleability. Accordingly, this low-temperature deposition method of modifying polymeric separators is attractive for application in high-performance LIBs.

  9. The influence of chemicals on water quality in a high pressure separation rig

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Einar E.; Hemmingsen, Paal V.; Mediaas, Heidi; Svarstad, May Britt E.; Westvik, Arild

    2006-03-15

    In the research laboratory of Statoil at Rotvoll, Trondheim, a high pressure experimental rig used for separation and foaming studies has been developed. There have been several studies to ensure that the high pressure separation rig produces reliable and consistent results with regard to the water-in-oil and oil-in-water contents. The results are consistent with available field data and, just as important, consistent when changing variables like temperature, pressure drop and water cut. The results are also consistent when changing hydrodynamic variables like flow velocity and mixing point (using different choke valves) and when using oil with and without gas saturation. At equal experimental conditions, the high pressure separation rig is able to differentiate between separation characteristics of oil and water from different fields and from different wells at the same field. The high pressure separation and foam rig can be used from -10 deg C to 175 deg C and at pressures up to 200 bar. Crude oil and water are studied under relevant process conditions with respect to temperature, pressure, shear, water cut and separation time. In the present work the influence of chemicals on the oil and water quality has been studied. Chemicals have been mixed into the oil and/or water beforehand or added in situ (on-stream; simulated well stream). The amount of oil in the water after a given residence time in the separation cell has been measured. The results from the high pressure rig show that some demulsifiers, with their primary purpose of giving less water in oil, also have influence on the water quality. Improvement of water quality has been observed as well as no effect or aggravation. The experimental results have been compared to results from bottle tests at the field. The results from the bottle tests and from the laboratory are not corresponding, and only a full-scale field test can tell which of them are the correct results, if any. (Experience from corresponding

  10. Photocatalytic activity of tin-doped TiO{sub 2} film deposited via aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chua, Chin Sheng, E-mail: cschua@simtech.a-star.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Tan, Ooi Kiang; Tse, Man Siu [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Ding, Xingzhao [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore)

    2013-10-01

    Tin-doped TiO{sub 2} films are deposited via aerosol assisted chemical vapor deposition using a precursor mixture composing of titanium tetraisopropoxide and tetrabutyl tin. The amount of tin doping in the deposited films is controlled by the volume % concentration ratio of tetrabutyl tin over titanium tetraisopropoxide in the mixed precursor solution. X-ray diffraction analysis results reveal that the as-deposited films are composed of pure anatase TiO{sub 2} phase. Red-shift in the absorbance spectra is observed attributed to the introduction of Sn{sup 4+} band states below the conduction band of TiO{sub 2}. The effect of tin doping on the photocatalytic property of TiO{sub 2} films is studied through the degradation of stearic acid under UV light illumination. It is found that there is a 10% enhancement on the degradation rate of stearic acid for the film with 3.8% tin doping in comparison with pure TiO{sub 2} film. This improvement of photocatalytic performance with tin incorporation could be ascribed to the reduction of electron-hole recombination rate through charge separation and an increased amount of OH radicals which are crucial for the degradation of stearic acid. Further increase in tin doping results in the formation of recombination site and large anatase grains, which leads to a decrease in the degradation rate. - Highlights: ► Deposition of tin-doped TiO{sub 2} film via aerosol assisted chemical vapor deposition ► Deposited anatase films show red-shifted in UV–vis spectrum with tin-dopants. ► Photoactivity improves at low tin concentration but reduces at higher concentration. ► Improvement in photoactivity due to bandgap narrowing from Sn{sup 4+} band states ► Maximum photoactivity achieved occurs for films with 3.8% tin doping.

  11. Zero Valent Iron Nanoparticle Assisted Electrocoagulation of Arsenic with electromagnetic Separation of Solids

    Directory of Open Access Journals (Sweden)

    Nuñez P.

    2013-04-01

    Full Text Available A new arsenic removal process was designed combining: 1 iron nanoparticle addition, b electrocoagulation, and c electromagnetic separation. Results showed that arsenic could be removed with more than 99 % efficiency from liquid waste samples. Parameters that were found to have importance on the process were: a nanoparticle dosage, b electric voltage drop during electrocoagulation, b pH of the solution, d arsenic concentration, and e electromagnetic field distribution during solid separation. Arsenic could efficiently be removed by iron nanoparticles during electrocoagulation. Afterwards the arsenic containing particles were separated from the solution by electromagnetic fields. This new process could be a feasible alternative to conventional arsenic treatment in liquid waste streams.

  12. Evaluation Of Air Separator For Processing Particulate Chemical Industry Gas Streams

    Directory of Open Access Journals (Sweden)

    F. W. Ntengwe

    2015-08-01

    Full Text Available ABSTRACT The evaluations of an air separator for processing chemical engineering particulate gas streams was carried out with a view to investigate the performance for different flow rates and other characteristics. A louver LV air separator was used as a case study. The evaluations indicated that for various set points of characteristics the prediction of operating efficiencies could be made for different variations of louver gap LVG with area ratio AR length of separator at particular angles of LV inclination and the number of LV with flow rates. It was observed that efficiencies ranging from 40 to 60 on one hand were obtained for high values of LVG and gas flow rate. On the other hand efficiencies of 61 to 99 were obtained for lower values of LVG and gas flow rate. It was noted therefore that in order to produce high efficiencies the values of LVG and flow rates have to be low and vice versa. The evaluation indicates also that plant operators can quickly predict from the results the operating efficiency for the desired dimensions and or flow rates of particulate gas streams. The methodology for the determination of operating data can be used in minimum-time frame to optimize the operations of the plant.

  13. Performance analysis of solar-assisted chemical heat-pump dryer

    Energy Technology Data Exchange (ETDEWEB)

    Fadhel, M.I. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, 75450, Melaka (Malaysia); Sopian, K.; Daud, W.R.W. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2010-11-15

    A solar-assisted chemical heat-pump dryer has been designed, fabricated and tested. The performance of the system has been studied under the meteorological conditions of Malaysia. The system consists of four main components: solar collector (evacuated tubes type), storage tank, solid-gas chemical heat pump unit and dryer chamber. A solid-gas chemical heat pump unit consists of reactor, condenser and evaporator. The reaction used in this study (CaCl2-NH{sub 3}). A simulation has been developed, and the predicted results are compared with those obtained from experiments. The maximum efficiency for evacuated tubes solar collector of 80% has been predicted against the maximum experiment of 74%. The maximum values of solar fraction from the simulation and experiment are 0.795 and 0.713, respectively, whereas the coefficient of performance of chemical heat pump (COP{sup h}) maximum values 2.2 and 2 are obtained from simulation and experiments, respectively. The results show that any reduction of energy at condenser as a result of the decrease in solar radiation will decrease the coefficient of performance of chemical heat pump as well as decrease the efficiency of drying. (author)

  14. Novel Gas-assisted Three-liquid-phase Extraction System for Simultaneous Separation and Concentration of Anthraquinones in Herbal Extract

    Institute of Scientific and Technical Information of China (English)

    Xingfu Yang; Xiangfeng Liang; Liangrong Yang; Feng Pan; Fuli Deng; Huizhou Liu

    2014-01-01

    abstract Gas-assisted three-liquid-phase extraction (GATE), which has the advantages of both three-liquid-phase extrac-tion and solvent sublation, is a novel separation technique for separation and concentration of two organic com-pounds into different phases in one step. This highly effective and economically applicable method has been developed for separating emodin and rhein from herbal extract. In a GATE system composed of butyl acetate/PEG4000/ammonium sulfate aqueous solution, influence of various parameters including gas flow rate, flotation time, salt concentration, initial volume of PEG and butyl acetate was investigated. Within 50 min of 30 ml·min-1 nitrogen flow, removal ratio of emodin and rhein from aqueous phase could be over 99%and 97%, respectively. Mass fraction of emodin in the BA phase and rhein in the PEG phase could reach 97%and 95%, respectively. It is demonstrated that gas bubbling is effective for partitioning of emodin and rhein into butyl acetate and PEG phase respectively, and dispersed PEG and butyl acetate could be captured from the aqueous solution. Experi-mental results show that GATE could be an effective and economical technology for concentration and separation of co-existed products in medicinal plants.

  15. Chemicals loading in acetylated bamboo assisted by supercritical CO2 based on phase equilibrium data

    Science.gov (United States)

    Silviana, Petermann, M.

    2015-12-01

    Indonesia has a large tropical forest. However, the deforestation still appears annually and vastly. This reason drives a use of bamboo as wood alternative. Recently, there are many modifications of bamboo in order to prolong the shelf life. Unfortunately, the processes need more chemicals and time. Based on wood modification, esterifying of bamboo was undertaken in present of a dense gas, i.e. supercritical CO2. Calculation of chemicals loading referred to ASTM D1413-99 by using the phase equilibrium data at optimum condition by a statistical design. The results showed that the acetylation of bamboo assisted by supercritical CO2 required 14.73 kg acetic anhydride/m3 of bamboo for a treatment of one hour.

  16. Structural Evolution of SiC Films During Plasma-Assisted Chemical Vapour Deposition

    International Nuclear Information System (INIS)

    Evolution of chemical bonding configurations for the films deposited from hexamethyldisiloxane (HMDSO) diluted with H2 during plasma assisted chemical vapour deposition is investigated. In the experiment a small amount of CH4 was added to adjust the plasma environment and modify the structure of the deposited films. The measurements of Raman spectroscopy and X-ray diffraction (XRD) revealed the production of 6H-SiC embedded in the amorphous matrix without the input of CH4. As CH4 was introduced into the deposition reaction, the transition of 6H-SiC to cubic SiC in the films took place, and also the film surfaces changed from a structure of ellipsoids to cauliflower-like shapes. With a further increase of CH4 in the flow ratio, the obtained films varied from Si-C bonding dominant to a sp2/sp3 carbon-rich composition. (low temperature plasma)

  17. Graphene-Assisted Chemical Etching of Silicon Using Anodic Aluminum Oxides as Patterning Templates.

    Science.gov (United States)

    Kim, Jungkil; Lee, Dae Hun; Kim, Ju Hwan; Choi, Suk-Ho

    2015-11-01

    We first report graphene-assisted chemical etching (GaCE) of silicon by using patterned graphene as an etching catalyst. Chemical-vapor-deposition-grown graphene transferred on a silicon substrate is patterned to a mesh with nanohole arrays by oxygen plasma etching using an anodic- aluminum-oxide etching mask. The prepared graphene mesh/silicon is immersed in a mixture solution of hydrofluoric acid and hydro peroxide with various molecular fractions at optimized temperatures. The silicon underneath graphene mesh is then selectively etched to form aligned nanopillar arrays. The morphology of the nanostructured silicon can be controlled to be smooth or porous depending on the etching conditions. The experimental results are systematically discussed based on possible mechanisms for GaCE of Si. PMID:26473800

  18. Solvent Separating Secondary Metabolites Directly from Biosynthetic Tissue for Surface-Assisted Laser Desorption Ionisation Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    David Rudd

    2015-03-01

    Full Text Available Marine bioactive metabolites are often heterogeneously expressed in tissues both spatially and over time. Therefore, traditional solvent extraction methods benefit from an understanding of the in situ sites of biosynthesis and storage to deal with heterogeneity and maximize yield. Recently, surface-assisted mass spectrometry (MS methods namely nanostructure-assisted laser desorption ionisation (NALDI and desorption ionisation on porous silicon (DIOS surfaces have been developed to enable the direct detection of low molecular weight metabolites. Since direct tissue NALDI-MS or DIOS-MS produce complex spectra due to the wide variety of other metabolites and fragments present in the low mass range, we report here the use of “on surface” solvent separation directly from mollusc tissue onto nanostructured surfaces for MS analysis, as a mechanism for simplifying data annotation and detecting possible artefacts from compound delocalization during the preparative steps. Water, ethanol, chloroform and hexane selectively extracted a range of choline esters, brominated indoles and lipids from Dicathais orbita hypobranchial tissue imprints. These compounds could be quantified on the nanostructured surfaces by comparison to standard curves generated from the pure compounds. Surface-assisted MS could have broad utility for detecting a broad range of secondary metabolites in complex marine tissue samples.

  19. Microwave assisted rapid growth of Mg(OH)2 nanosheet networks for ethanol chemical sensor application

    International Nuclear Information System (INIS)

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

  20. Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

    Institute of Scientific and Technical Information of China (English)

    Salah ALJBOUR; Tomohiko TAGAWA; Mohammad MATOUQ; Hiroshi YAMADA

    2009-01-01

    The Lewis acid-catalyzed addition of tri-methylsilyl cyanide to p-chlorobenzaldehyde in a micro-channel reactor was investigated. The microchannel was integrated to promote both reaction and separation of the biphase system. FeF3 and Cu(triflate)2 were used as water-stable Lewis acid catalysts. Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphase flow inside the microchannel. It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system. Parallel multiphase flow inside the microchannel was obtained, allowing for continuous and acceptable phase separation. Enhanced selectivity was achieved by operating at lower conversion values.

  1. Zero Valent Iron Nanoparticle Assisted Electrocoagulation of Arsenic with electromagnetic Separation of Solids

    OpenAIRE

    Nuñez P.; Hansen H. K.

    2013-01-01

    A new arsenic removal process was designed combining: 1) iron nanoparticle addition, b) electrocoagulation, and c) electromagnetic separation. Results showed that arsenic could be removed with more than 99 % efficiency from liquid waste samples. Parameters that were found to have importance on the process were: a) nanoparticle dosage, b) electric voltage drop during electrocoagulation, b) pH of the solution, d) arsenic concentration, and e) electromagnetic field distribution during solid sepa...

  2. Near-Critical Fluctuations and Cytoskeleton-Assisted Phase Separation Lead to Subdiffusion in Cell Membranes

    OpenAIRE

    Ehrig, Jens; Petrov, Eugene P.; Schwille, Petra

    2011-01-01

    We address the relationship between membrane microheterogeneity and anomalous subdiffusion in cell membranes by carrying out Monte Carlo simulations of two-component lipid membranes. We find that near-critical fluctuations in the membrane lead to transient subdiffusion, while membrane-cytoskeleton interaction strongly affects phase separation, enhances subdiffusion, and eventually leads to hop diffusion of lipids. Thus, we present a minimum realistic model for membrane rafts showing the featu...

  3. Graphene-assisted growth of high-quality AlN by metalorganic chemical vapor deposition

    Science.gov (United States)

    Zeng, Qing; Chen, Zhaolong; Zhao, Yun; Wei, Tongbo; Chen, Xiang; Zhang, Yun; Yuan, Guodong; Li, Jinmin

    2016-08-01

    High-quality AlN films were directly grown on graphene/sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The graphene layers were directly grown on sapphire by atmospheric-pressure chemical vapor deposition (APCVD), a low-cost catalyst-free method. We analyzed the influence of the graphene layer on the nucleation of AlN at the initial stage of growth and found that sparse AlN grains on graphene grew and formed a continuous film via lateral coalescence. Graphene-assisted AlN films are smooth and continuous, and the full width at half maximum (FWHM) values for (0002) and (10\\bar{1}2) reflections are 360 and 622.2 arcsec, which are lower than that of the film directly grown on sapphire. The high-resolution TEM images near the AlN/sapphire interface for graphene-assisted AlN films clearly show the presence of graphene, which kept its original morphology after the 1200 °C growth of AlN.

  4. Aerosol-Assisted Chemical Vapor Deposited Thin Films for Space Photovoltaics

    Science.gov (United States)

    Hepp, Aloysius F.; McNatt, Jeremiah; Dickman, John E.; Jin, Michael H.-C.; Banger, Kulbinder K.; Kelly, Christopher V.; AquinoGonzalez, Angel R.; Rockett, Angus A.

    2006-01-01

    Copper indium disulfide thin films were deposited via aerosol-assisted chemical vapor deposition using single source precursors. Processing and post-processing parameters were varied in order to modify morphology, stoichiometry, crystallography, electrical properties, and optical properties in order to optimize device-quality material. Growth at atmospheric pressure in a horizontal hot-wall reactor at 395 C yielded best device films. Placing the susceptor closer to the evaporation zone and flowing a more precursor-rich carrier gas through the reactor yielded shinier, smoother, denser-looking films. Growth of (112)-oriented films yielded more Cu-rich films with fewer secondary phases than growth of (204)/(220)-oriented films. Post-deposition sulfur-vapor annealing enhanced stoichiometry and crystallinity of the films. Photoluminescence studies revealed four major emission bands (1.45, 1.43, 1.37, and 1.32 eV) and a broad band associated with deep defects. The highest device efficiency for an aerosol-assisted chemical vapor deposited cell was 1.03 percent.

  5. Chemical investigations of isotope separation on line target units for carbon and nitrogen beams

    CERN Document Server

    Franberg, H; Gäggeler, H W; Köster, U

    2006-01-01

    Radioactive ion beams (RIBs) are of significant interest in a number of applications. Isotope separation on line (ISOL) facilities provide RIB with high beam intensities and good beam quality. An atom that is produced within the ISOL target will first diffuse out from the target material. During the effusion towards the transfer line and into the ion source the many contacts with the surrounding surfaces may cause unacceptable delays in the transport and, hence, losses of the shorter-lived isotopes. We performed systematic chemical investigations of adsorption in a temperature and concentration regime relevant for ISOL targets and ion source units, with regard to CO/sub x/ and NOmaterials are potential construction materials for the above-mentioned areas. Off-line and on-line tests have been performed using a gas thermochromatography setup with radioactive tracers. The experiments were performed at the production of tracers for atmospheric chemistry (PROTRAC) facility at the Paul Schener Institute in Villigen...

  6. Gas separation performance of 6FDA-based polyimides with different chemical structures

    KAUST Repository

    Qiu, Wulin

    2013-10-01

    This work reports the gas separation performance of several 6FDA-based polyimides with different chemical structures, to correlate chemical structure with gas transport properties with a special focus on CO2 and CH 4 transport and plasticization stability of the polyimides membranes relevant to natural gas purification. The consideration of the other gases (He, O2 and N2) provided additional insights regarding effects of backbone structure on detailed penetrant properties. The polyimides studied include 6FDA-DAM, 6FDA-mPDA, 6FDA-DABA, 6FDA-DAM:DABA (3:2), 6FDA-DAM:mPDA (3:2) and 6FDA-mPDA:DABA (3:2). Both pure and binary gas permeation were investigated. The packing density, which is tunable by adjusting monomer type and composition of the various samples, correlated with transport permeability and selectivity. The separation performance of the polyimides for various gas pairs were also plotted for comparison to the upper bound curves, and it was found that this family of materials shows attractive performance. The CO 2 plasticization responses for the un-cross-linked polyimides showed good plasticization resistance to CO2/CH4 mixed gas with 10% CO2; however, only the cross-linked polyimides showed good plasticization resistance under aggressive gas feed conditions (CO 2/CH4 mixed gas with 50% CO2 or pure CO 2). For future work, asymmetric hollow fibers and carbon molecular sieve membranes based on the most attractive members of the family will be considered. © 2013 Elsevier Ltd. All rights reserved.

  7. The development of chemical separation technology for an advanced Purex process

    International Nuclear Information System (INIS)

    Future reprocessing plants will require flexible processes that minimise the environmental impact and improve cost effectiveness. This paper discusses some of the technical advances made in the Chemical Separation area of BNFL's Advanced Purex project. An integrated approach involving fundamental process chemistry, computer modelling and flow-sheeting, equipment development, and small scale confirmation trials, has been adopted. The main aims of the project are process simplification and intensification, and this has led to the development of flexible single cycle flowsheets using centrifugal contactors. In order to achieve this cost effectively, comprehensive computer models have been developed based on extraction algorithms for all the major actinide and fission product species. These models also incorporate reaction kinetics, radiolysis, TBP degradation products, and contactor data. The models have been validated by data from plant and from miniature multi-stage centrifugal contactor rigs. One rig has been used to run counter-current α-active flowsheet trials with both on-line and off-line analysis. In parallel, contactor development has concentrated on the scaling up of centrifugal contactor stages up to industrial sizes and obtaining engineering data such as mass transfer rates in single stages. Chemical development is focused on both the accumulation of data needed in computer modelling such as distribution coefficients and reaction rates, and more fundamental research in to new separation processes including chelating agent based flowsheets and new salt free reducing agents. In particular key species, such as Np, Tc, Pu and U(IV), which have a significant impact on the efficiency of single cycle flowsheets are targeted. This paper will report developments in these areas, particularly highlighting how they are integrated in the design of Advanced Purex flowsheets. (author)

  8. The Gaia-ESO Survey: Separating disk chemical substructures with cluster models

    CERN Document Server

    Rojas-Arriagada, A; de Laverny, P; Schultheis, M; Guiglion, G; Mikolaitis, Š; Kordopatis, G; Hill, V; Gilmore, G; Randich, S; Alfaro, E J; Bensby, T; Koposov, S E; Costado, M T; Franciosini, E; Hourihane, A; Jofré, P; Lardo, C; Lewis, J; Lind, K; Magrini, L; Monaco, L; Morbidelli, L; Sacco, G G; Worley, C C; Zaggia, S; Chiappini, C

    2015-01-01

    (Abridged) Recent spectroscopic surveys have begun to explore the Galactic disk system outside the solar neighborhood on the basis of large data samples. In this way, they provide valuable information for testing spatial and temporal variations of disk structure kinematics and chemical evolution. We used a Gaussian mixture model algorithm, as a rigurous mathematical approach, to separate in the [Mg/Fe] vs. [Fe/H] plane a clean disk star subsample from the Gaia-ESO survey internal data release 2. We find that the sample is separated into five groups associated with major Galactic components; the metal-rich end of the halo, the thick disk, and three subgroups for the thin disk sequence. This is confirmed with a sample of red clump stars from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. The two metal-intermediate and metal-rich groups of the thin disk decomposition ([Fe/H]>-0.25 dex) highlight a change in the slope at solar metallicity. This holds true at different radial regions. ...

  9. Field evidence for strong chemical separation of contaminants inthe Hanford Vadose Zone

    Energy Technology Data Exchange (ETDEWEB)

    Conrad, Mark E.; DePaolo, Donald J.; Maher, Katharine; Gee,Glendon W.; Ward, Anderson L.

    2007-04-10

    Water and chemical transport from a point source withinvadose zone sediments at Hanford were examined with a leak testconsisting of five 3800-liter aliquots of water released at 4.5 m depthevery week over a 4-week period. The third aliquot contained bromide, D2Oand 87Sr. Movement of the tracers was monitored for 9 months by measuringpore water compositions of samples from boreholes drilled 2-8 m from theinjection point. Graded sedimentary layers acting as natural capillarybarriers caused significant lateral spreading of the leak water. D2Oconcentrations>50 percent of the concentration in the tracer aliquotwere detected at 9-11 m depth. However, increased water contents, lowerd18O values, and geophysical monitoring of moisture changes at otherdepths signified high concentrations of leak fluids were added where D2Oconcentrations were<3 percent above background, suggesting limitedmixing between different aliquots of the leak fluids. Initially highbromide concentrations decreased more rapidly over time than D2O,suggesting enhanced transport of bromide due to anion exclusion. Nosignificant increase in 87Sr was detected in the sampled pore water,indicating strong retardation of Sr by the sediments. These resultshighlight some of the processes strongly affecting chemical transport inthe vadose zone and demonstrate the significant separation of contaminantplumes that can occur.

  10. Phonon-assisted ultrafast charge separation in the PCBM band structure

    Science.gov (United States)

    Smith, Samuel L.; Chin, Alex W.

    2015-05-01

    Organic solar cells separate strongly bound electron-hole pairs into free charges at interfaces between electron donor and acceptor organic semiconductors. Recently, electron-hole separation was observed on femtosecond time scales near crystallite phases of the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PCBM), which is incompatible with conventional Marcus theories of organic transport. Here we show that ultrafast charge transport in PCBM arises from its broad range of electronic eigenstates, provided by three closely spaced electronic bands near the lowest unoccupied molecular orbital. The highest band provides a charge transfer state resonant with delocalized states of the lower two bands away from the interface. This state acts as a bridge between the donor phase and the acceptor bulk, bypassing the trapped charge-transfer (CT) states below. Vibrational fluctuations enable rapid electronic transitions across this bridge, which can drive the electron more than 4 nm away from the interface within 100 fs. All this is demonstrated within a simple tight-binding Hamiltonian containing transfer integrals no larger than 8 meV.

  11. Use of computer-assisted prediction of toxic effects of chemical substances

    International Nuclear Information System (INIS)

    The current revision of the European policy for the evaluation of chemicals (REACH) has lead to a controversy with regard to the need of additional animal safety testing. To avoid increases in animal testing but also to save time and resources, alternative in silico or in vitro tests for the assessment of toxic effects of chemicals are advocated. The draft of the original document issued in 29th October 2003 by the European Commission foresees the use of alternative methods but does not give further specification on which methods should be used. Computer-assisted prediction models, so-called predictive tools, besides in vitro models, will likely play an essential role in the proposed repertoire of 'alternative methods'. The current discussion has urged the Advisory Committee of the German Toxicology Society to present its position on the use of predictive tools in toxicology. Acceptable prediction models already exist for those toxicological endpoints which are based on well-understood mechanism, such as mutagenicity and skin sensitization, whereas mechanistically more complex endpoints such as acute, chronic or organ toxicities currently cannot be satisfactorily predicted. A potential strategy to assess such complex toxicities will lie in their dissection into models for the different steps or pathways leading to the final endpoint. Integration of these models should result in a higher predictivity. Despite these limitations, computer-assisted prediction tools already today play a complementary role for the assessment of chemicals for which no data is available or for which toxicological testing is impractical due to the lack of availability of sufficient compounds for testing. Furthermore, predictive tools offer support in the screening and the subsequent prioritization of compound for further toxicological testing, as expected within the scope of the European REACH program. This program will also lead to the collection of high-quality data which will broaden the

  12. Ultrasound- assisted emulsification microextraction for separation of trace amounts of antimony prior to FAAS determination

    International Nuclear Information System (INIS)

    We describe a simple and rapid method for the ultrasound-assisted microextraction of antimony using the solidified floating organic drop method. The effects of pH, type and volume of the extractant, time of sonication, amount of chelating agent, type and amount of surfactant were investigated and optimized. Bromopyrogollol red is acting as the chelating agent. Antimony(III) ion was extracted into finely dispersed droplets of undecanol after ion-pair formation with the water soluble chelator and the cationic detergent benzyldimethyltetradecylammonium chloride. Flame atomic absorption spectrometry was used for the detection. The resulting calibration is linear in the concentration range from 4. 0 to 900 ng mL-1 of Sb(III) with a correlation coefficient of 0. 9981. The enrichment factor is 67, the detection limit is 0. 62 ng mL-1, and the relative standard deviation is ±3. 6% (at 100 ng mL-1; for n = 10). The method was successfully applied to the determination of antimony in water samples. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-15

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

  14. Program of technical assistance to the organization for the prohibition of chemical weapons, informal report

    Energy Technology Data Exchange (ETDEWEB)

    1995-01-01

    Currently, U.S. organizations provide technical support to the U.S. Delegation for its work as part of the Preparatory Commission (PrepCom) of the Organization for the Prohibition of Chemical Weapons (OPCW) in The Hague. The current efforts of the PrepCom are focussed on preparations for the Entry-Into-Force (EIF) of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons (often referred to as the {open_quotes}Chemical Weapons Convention{close_quotes} (CWC)). EIF of the CWC is expected in 1995, and shortly thereafter the PrepCom will cease to exist, with the OPCW taking over responsibilities under the CWC. A U.S. program of technical assistance to the OPCW for its verification responsibilities may be created as part of U.S. policy objectives after EIF of the CWC. In the summary below, comments by participants are presented in Square Brackets Some of the same points arose several times during the discussions; they are grouped together under the most pertinent heading.

  15. Oxygen permeation and thermo-chemical stability of oxygen separation membrane materials for the oxyfuel process

    Energy Technology Data Exchange (ETDEWEB)

    Ellett, Anna Judith

    2009-07-01

    The reduction of CO{sub 2} emissions, generally held to be one of the most significant contributors to global warming, is a major technological issue. CO{sub 2} Capture and Storage (CCS) techniques applied to large stationary sources such as coal-fired power plants could efficiently contribute to the global carbon mitigation effort. The oxyfuel process, which consists in the burning of coal in an oxygen-rich atmosphere to produce a flue gas highly concentrated in CO{sub 2}, is a technology considered for zero CO{sub 2} emission coal-fired power plants. The production of this O{sub 2}-rich combustion gas from air can be carried out using high purity oxygen separation membranes. Some of the most promising materials for this application are mixed ionic-electronic conducting (MIEC) materials with perovskite and K{sub 2}NiF{sub 4} perovskite-related structures. The present work examines the selection of La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF58), La{sub 2}NiO{sub 4+{delta}}, Pr{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (PSCF58) and Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF50) as membrane materials for the separation of O{sub 2} and N{sub 2} in the framework of the oxyfuel process with flue gas recycling. Annealing experiments were carried out on pellets exposed to CO{sub 2}, water vapour, O{sub 2} and Cr{sub 2}O{sub 3} in order to determine the thermo-chemical resistance to the atmospheres and the high temperature conditions present during membrane operation in a coal-fired power plant. The degradation of their microstructure was investigated using Scanning Electron Microscopy (SEM) in combination with electron dispersive spectroscopy (EDS) as well as X-Ray Diffraction (XRD). Also, the oxygen permeation fluxes of selected membranes were investigated as a function of temperature. The membrane materials selected were characterised using thermo-analytical techniques such as precision thermogravimetric

  16. Electron behaviour in CH4/H2 gas mixture in electron-assisted chemical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    Dong Li-Fang; Ma Bo-Qin; Wang Zhi-Jun

    2004-01-01

    The behaviour of electrons in CH4/H2 gas mixture in electron-assisted chemical vapour deposition of diamond is investigated using Monte Carlo simulation. The electron drift velocity in gas mixture is obtained over a wide range of E/P (the ratio of the electric field to gas pressure) from 1500 to 300000 (V/m kPa-1). The electron energy distribution and average energy under different gas pressure (0.1-20kPa) and CH4 concentration (0.5%-10.0%) are calculated. Their effects on the diamond growth are also discussed. It is believed that these results will be helpful to the selection of optimum experimental conditions for high quality diamond film deposition.

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

    Directory of Open Access Journals (Sweden)

    Januś M.

    2015-06-01

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

  18. In situ doping of ZnO nanowires using aerosol-assisted chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Pung, Swee-Yong; Choy, Kwang-Leong; Hou Xianghui; Dinsdale, Keith, E-mail: Kwang-leong.Choy@nottingham.ac.uk [Faculty of Engineering, Energy and Sustainability Research Division, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2010-08-27

    An in situ doping approach of producing Al-doped ZnO NWs was demonstrated using an aerosol-assisted chemical vapour deposition (AA-CVD) technique. In this technique, Zn precursor was kept in the middle of a horizontal tube furnace whereas the dopant solution was kept in an aerosol generator, which was located outside the furnace. The Al aerosol was flowed into the reactor during the growth of NWs in order to achieve in situ doping. Al-doped ZnO NWs were synthesized as verified by the combination of XRD, TEM/EDS and TOF-SIMS analysis. Highly (00.2) oriented ZnO seed layers were used to promote vertically aligned growth of Al-doped ZnO NWs. Lastly, a growth mechanism of vertically aligned Al-doped ZnO NWs was discussed.

  19. Biological functionalization and patterning of porous silicon prepared by Pt-assisted chemical etching

    International Nuclear Information System (INIS)

    Porous silicon fabricated via Pt-assisted chemical etching of p-type Si (1 0 0) in 1:1:1 EtOH/HF/H2O2 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.

  20. Deep and vertical silicon bulk micromachining using metal assisted chemical etching

    International Nuclear Information System (INIS)

    In this paper, a newfound and simple silicon bulk micromachining process based on metal-assisted chemical etching (MaCE) is proposed which opens a whole new field of research in MEMS technology. This method is anisotropic and by controlling the etching parameters, deep vertical etching, relative to substrate surface, can be achieved in micrometer size for 〈1 0 0〉 oriented Si wafer. By utilizing gold as a catalyst and a photoresist layer as the single mask layer for etching, 60 µm deep gyroscope micromachined structures have been fabricated for 2 µm features. The results indicate that MaCE could be the only wet etching method comparable to conventional dry etching recipes in terms of achievable etch rate, aspect ratio, verticality and side wall roughness. It also does not need a vacuum chamber and the other costly instruments associated with dry etching techniques. (paper)

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

    Directory of Open Access Journals (Sweden)

    R. W. Wu

    2016-02-01

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

  2. Bilayer-metal assisted chemical etching of silicon microwire arrays for photovoltaic applications

    Science.gov (United States)

    Wu, R. W.; Yuan, G. D.; Wang, K. C.; Wei, T. B.; Liu, Z. Q.; Wang, G. H.; Wang, J. X.; Li, J. M.

    2016-02-01

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

  3. Triangle pore arrays fabricated on Si (111) substrate by sphere lithography combined with metal-assisted chemical etching and anisotropic chemical etching

    OpenAIRE

    Asoh, Hidetaka; Fujihara, Kosuke; Ono, Sachiko

    2012-01-01

    The morphological change of silicon macropore arrays formed by metal-assisted chemical etching using shape-controlled Au thin film arrays was investigated during anisotropic chemical etching in tetramethylammonium hydroxide (TMAH) aqueous solution. After the deposition of Au as the etching catalyst on (111) silicon through a honeycomb mask prepared by sphere lithography, the specimens were etched in a mixed solution of HF and H2O2 at room temperature, resulting in the formation of ordered mac...

  4. Physical–chemical characteristics of lignins separated from biomasses for second-generation ethanol

    International Nuclear Information System (INIS)

    Lignin was extracted by two extraction methods from two biomasses for energy (Mischantus and Giant Reed) and a lignocellulosic material resulting from a microbial treatment of giant reed. One method of extraction involved the use of H2SO4 (SA), providing a highly aromatic water-insoluble material, while a second method employed H2O2 at alkaline pH (Ox), resulting in a water-soluble lignin. Extraction yields were related to the total Klason lignin measured for the three materials. We compared the physical–chemical features of the isolated lignins, by employing solid-state nuclear magnetic resonance spectroscopy (13C-CPMAS spectra and derived T1ρH relaxation times), thermogravimetric analyses, infrared spectrometry and high performance size exclusion chromatography (HPSEC). We found that lignin separated by the Ox method owned a more mobile molecular conformation, and was largely more water-soluble and fragmented than the lignin obtained by the SA treatment. In line with T1ρH-NMR and thermogravimetric results, the HPSEC of Ox lignins showed nominal molecular weights less than 3 kDa, indicating well depolymerized materials. Such low-molecular weight and fragmented lignin obtained from biomasses for energy may become useful for application of recycled products in agriculture and in green chemistry reactions, thereby promoting an increase in the economic sustainability of biorefineries. - Highlights: • Lignin extracted from energy crops by either acidic or alkaline treatment. • Lignin chemical features were assessed by analytical and spectroscopic techniques. • Acidic extraction gave poorly water-soluble and conformationally rigid lignins. • Alkaline oxidation produced depolymerized and water-soluble lignins. • Water-soluble lignins may be environmentally and industrially useful

  5. Chemical characteristics and methane potentials of source-separated and pre-treated organic municipal solid waste

    DEFF Research Database (Denmark)

    Hansen, Trine Lund; Svärd, Å; Angelidaki, Irini;

    2003-01-01

    A research project has investigated the biogas potential of pre-screened source-separated organic waste. Wastes from five Danish cities have been pre-treated by three methods: screw press; disc screen; and shredder and magnet. This paper outlines the sampling procedure used, the chemical composit......A research project has investigated the biogas potential of pre-screened source-separated organic waste. Wastes from five Danish cities have been pre-treated by three methods: screw press; disc screen; and shredder and magnet. This paper outlines the sampling procedure used, the chemical...... composition of the wastes and the estimated methane potentials....

  6. Formation of SiC Nanostruture Using Hexamethyldisiloxane During Plasma-Assisted Hot-Filament Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    Growth of SiC nanowires in plasma-assisted hot filament chemical-vapor-deposition by using hexamethyldisiloxane (HMDSO) as the gas source is reported. The SiC nanowires (SiC-NWs) grew on Au-coated silicon substrate with core-shell structure, where the core consisted of polycrystalline SiC grains and the shell exhibited amorphous structure. The featured structures such as cones, polyhedrons, ball-liked particles were observed in the case without plasma assistance. The underlying mechanism for the growth of nanostructures was also discussed. The high chemical activity induced by the plasma process plays an important role in using monomer to generate nanostructure.

  7. Studies on the remediation of environment contaminated with radioactive pollutants using the chemical separation technique

    International Nuclear Information System (INIS)

    Remediation of soil and drinking water contaminated with radioactive nuclides is important for the mitigation of radiation exposure. Then we attempted to construct the remediation system including the dose estimation system using the chemical separation technique to remove pollutants from the environment. The information on air dose rate is important for assessment of risk from the radiation exposure. Then we measured the air dose rate and analysed the relationship between air dose rate and the contamination of soil at the area in Russia (Bryansk district) contaminated by Chernobyl Nuclear Power Plant accident. Moreover, we analysed the soil of Bryansk district on the concentration of rare earth elements, thorium and uranium and on the isotope ratio of strontium. On the other hand, we tried to develop the rapid measurement method of radioactivity of Sr-90 which is one of the dangerous radionuclides, because the method of radioactivity measurement in the literature is too time-consuming. It was reported recently that the molecules containing SH group form the covalent bond with gold atoms at the surface of gold plate and that crown ether compounds have strong affinity to strontium. Then we attempted to synthesize the crown ether containing SH group. In addition, we search the inorganic elements accumulated to special organisms of fishes and other animals in sea in order to find out new reagent for trace elements. Transition metal such as Co, Fe, Ni, Ti, V and Zn were detected from the intracellular granules in the bronchial heart of octopus. (author)

  8. The Application of High–Gradient Magnetic Separation to Water Treatment by Means of Chemically Precipitated Magnetite

    OpenAIRE

    Hencl, V.; Mucha, P.

    1994-01-01

    Conditions of high–gradient magnetic separation (HGMS) of chemically precipitated magnetite, prepared from a waste material of the titanium white production were studied. The magnetite was used as a sorption material for the treatment of water from the Vltava River. Detailed experimental research resulted in a proposal for a technology of water treatment, schematic description of which is presented. The results of HGMS of chemically precipitated magnetite together with those of water treatmen...

  9. Nanocomposite Coatings Codeposited with Nanoparticles Using Aerosol-Assisted Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Xianghui Hou

    2013-01-01

    Full Text Available Incorporating nanoscale materials into suitable matrices is an effective route to produce nanocomposites with unique properties for practical applications. Due to the flexibility in precursor atomization and delivery, aerosol-assisted chemical vapour deposition (AACVD process is a promising way to synthesize desired nanocomposite coatings incorporating with preformed nanoscale materials. The presence of nanoscale materials in AACVD process would significantly influence deposition mechanism and thus affect microstructure and properties of the nanocomposites. In the present work, inorganic fullerene-like tungsten disulfide (IF-WS2 has been codeposited with Cr2O3 coatings using AACVD. In order to understand the codeposition process for the nanocomposite coatings, chemical reactions of the precursor and the deposition mechanism have been studied. The correlation between microstructure of the nanocomposite coatings and the codeposition mechanism in the AACVD process has been investigated. The heterogeneous reaction on the surface of IF-WS2 nanoparticles, before reaching the substrate surface, is the key feature of the codeposition in the AACVD process. The agglomeration of nanoparticles in the nanocomposite coatings is also discussed.

  10. A Chemical Eight Group Separation Method for Routine Use in Gamma Spectrometric Analysis. II. Detailed analytical schema

    International Nuclear Information System (INIS)

    A detailed ion-exchange procedure for the separation of chemical elements in eight groups suitable for subsequent gamma spectrometric analysis is described. The method has been in use for gamma spectrometry of some inorganic - but mostly organic - samples for one year. The separation time for inorganic samples, is usually about 1.5 hours and for organic samples as least 2 hours. One man can separate and count three samples per day. In comparative measurements of short-lived isotopes in biological material 10-12 elements can be analysed thus making possible 30 - 35 determinations per day for one man

  11. Research on separation and extraction technology of the light element isotopes by the chemical exchange process

    International Nuclear Information System (INIS)

    It was clarified that the separation coefficient became 1.036, and succeeded in the development of the new, efficient lithium separator (Sodium Super-Ionic Conductor: NASICON) which is the elution liquid in the acid processed phosphate system for the lithium isotope separation technology. NASICON can be used in the column for the isotope separation, repeatedly if the nitric acid is used for the elution liquid and the hydroxide lithium or the acetic acid lithium solution as an adsorption solution of the lithium. Furthermore, the separation coefficient of 1.029 was obtained using the glucamine resin of the ester system for the boron isotope separation technology. (H. Katsuta)

  12. 2,4-Difluoro anisole. A promising complexing agent for boron isotopes separation by chemical exchange reaction and distillation

    International Nuclear Information System (INIS)

    Although methods of boron isotopes separation were intensively pursued about 60 years, the chemical exchange distillation is the only method that has been applied in industrial scale production of 10B. The present anisole BF3 system suffers from the drawbacks like high melting point, relatively low separation coefficient and instability under reaction conditions, which demand a continuous search for more effective and efficient donors for boron isotope separation. A series of fluoro-substituted anisole derivatives were screened in this paper, among which 2,4-difluoro anisole exhibited good properties compared with anisole. Studies on the boron trifluoride and 2,4-difluoro anisole adduct, its thermodynamic and physical properties related to large-scale isotopic separation is reported. The results showed that 2,4-difluoro anisole is better than anisole in separation coefficient, freezing point and stability under pyrolysis conditions, which suggest a further detailed investigations on boron trifluoride and 2,4-difluoro anisole adduct. (author)

  13. Using electrospray-assisted laser desorption/ionization mass spectrometry to characterize organic compounds separated on thin-layer chromatography plates.

    Science.gov (United States)

    Lin, Shu-Yao; Huang, Min-Zong; Chang, Hui-Chiu; Shiea, Jentaie

    2007-11-15

    Electrospray-assisted laser desorption/ionization (ELDI), an ionization method that combines laser desorption and electrospray ionization (ESI), can be used under ambient conditions to characterize organic compounds (including FD&C dyes, amines, extracts of a drug tablet) separated in the central track on a thin-layer chromatography (TLC) plate coated with either reversed-phase C18 particles or normal-phase silica gel. After drying, the TLC plate was placed on an acrylic sample holder set in front of the sampling skimmer of an ion trap mass analyzer. The chemicals at the center of the TLC plate were analyzed by pushing the sample holder into the path of a laser beam with a syringe pump. The molecules in the sample spot were desorbed by continuously irradiating the surface of the TLC plate with a pulsed nitrogen laser. Then, the desorbed sample molecules entered an ESI plume where they were ionized through the reactions with the charged species (including protons, hydronium ions and their cluster ions, solvent ions, and charged droplets) generated by electrospraying a methanol/water solution. MS/MS analyses were also performed to further characterize the analytes. The detection limit of TLC/ELDI/MS is approximately 10(-6) M. This was evaluated by using FD&C red dye as the standard. A linear relationship was found for the calibration curve with the concentration of FD&C red dye ranged from 10(-3) to 10(-6) M. PMID:17929897

  14. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    Science.gov (United States)

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI. PMID:26922843

  15. A phase separation method for analyses of fluoroquinones in meats based on ultrasound-assisted salt-induced liquid-liquid microextraction and a new integrated device

    OpenAIRE

    Wang, H; Gao, M.; Xu, Y; W. Wang; Zheng, L; Dahlgren, RA; Wang, X.

    2015-01-01

    © 2015 Elsevier Ltd. Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted, salt-induced, liquid-liquid microextraction for determination of five fluoroquinones in meats by HPLC analysis. The novel integrated device consisted of three simple HDPE (high density polyethylene) parts that were used to separate the solvent from the aqueous solution prior to retrieving the extractant. The extraction parameters were optimized using the response surfa...

  16. Integration of phase separation with ultrasound-assisted salt-induced liquid-liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography

    OpenAIRE

    Wang, H; Gao, M.; Wang, M.; Zhang, R.; W. Wang; Dahlgren, RA; Wang, X.

    2015-01-01

    © 2015 Elsevier B.V. Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on centr...

  17. Charge Exchange Reaction in Dopant-Assisted Atmospheric Pressure Chemical Ionization and Atmospheric Pressure Photoionization

    Science.gov (United States)

    Vaikkinen, Anu; Kauppila, Tiina J.; Kostiainen, Risto

    2016-04-01

    The efficiencies of charge exchange reaction in dopant-assisted atmospheric pressure chemical ionization (DA-APCI) and dopant-assisted atmospheric pressure photoionization (DA-APPI) mass spectrometry (MS) were compared by flow injection analysis. Fourteen individual compounds and a commercial mixture of 16 polycyclic aromatic hydrocarbons were chosen as model analytes to cover a wide range of polarities, gas-phase ionization energies, and proton affinities. Chlorobenzene was used as the dopant, and methanol/water (80/20) as the solvent. In both techniques, analytes formed the same ions (radical cations, protonated molecules, and/or fragments). However, in DA-APCI, the relative efficiency of charge exchange versus proton transfer was lower than in DA-APPI. This is suggested to be because in DA-APCI both dopant and solvent clusters can be ionized, and the formed reagent ions can react with the analytes via competing charge exchange and proton transfer reactions. In DA-APPI, on the other hand, the main reagents are dopant-derived radical cations, which favor ionization of analytes via charge exchange. The efficiency of charge exchange in both DA-APPI and DA-APCI was shown to depend heavily on the solvent flow rate, with best efficiency seen at lowest flow rates studied (0.05 and 0.1 mL/min). Both DA-APCI and DA-APPI showed the radical cation of chlorobenzene at 0.05-0.1 mL/min flow rate, but at increasing flow rate, the abundance of chlorobenzene M+. decreased and reagent ion populations deriving from different gas-phase chemistry were recorded. The formation of these reagent ions explains the decreasing ionization efficiency and the differences in charge exchange between the techniques.

  18. Scalable route to CH3NH3PbI3 perovskite thin films by aerosol assisted chemical vapour deposition

    OpenAIRE

    Bhachu, D. S.; Scanlon, D. O.; Saban, E. J.; Bronstein, H.; Parkin, I. P.; Carmalt, C. J.; Palgrave, R. G.

    2015-01-01

    Methyl-ammonium lead iodide is the archetypal perovskite solar cell material. Phase pure, compositionally uniform methyl-ammonium lead iodide thin films on large glass substrates were deposited using ambient pressure aerosol assisted chemical vapour deposition. This opens up a route to efficient scale up of hybrid perovskite film growth towards industrial deployment.

  19. Physico-Chemical Study of the Separation of Calcium Isotopes by Chemical Exchange Between Amalgam and Salt Solutions

    International Nuclear Information System (INIS)

    In a preliminary study of the isotopic exchange between Ca amalgam and aqueous or organic solutions of Ca salts, the main parameters governing the feasibility of a separation process based on these systems such as separation factor, exchange kinetics, rate of decomposition of the amalgam were investigated. The separation factor between 40Ca and 46Ca was found to be of the order of 1.02. The rate of the exchange reaction is rather low for aqueous solutions, extremely low for organic solutions. The amalgam seems not to be attacked by dimethyl-formamide solutions; but it is rapidly decomposed by aqueous solutions of Ca halides. This decomposition is slow in the case of aqueous solutions of calcium formate and still slower for Ca(OH)2; however, except in particular conditions, the observed rate is often much higher, owing to interfering reactions between amalgam and water vapor contained in H2 bubbles. (authors)

  20. Development of method to chemical separation of gallium-67 by thermal diffusion technique

    International Nuclear Information System (INIS)

    Radioisotopes of gallium have been studied and evaluated for medical applications since 1949. Over the past 50 years 67Ga has been widely used in the diagnosis of various diseases, including acute and chronic inflammatory lesions, bacterial or sterile and several types of tumors. In Brazil 30% of clinics that provide services for Nuclear Medicine use 67Ga citrate and the demand for 67Ga at IPEN-CNEN/SP is 37 GBq (1 Ci)/week. The 67Ga presents physical half-life of 3.26 days (78 hours) and decays 100% by electron capture to stable 67Zn. Its decay includes the emission of γ rays with energies of 93.3 keV (37%), 184.6 keV (20.4%), 300.2 keV (16.6%) and 888 keV (26%). In the past 67Ga was produced by the reaction 68Zn (p, 2n) 67Ga at IPEN-CNEN/SP. After irradiation, the target was dissolved in concentrated HCl and the solution percolated through a cationic resin DOWEX 50W-X8, 200-400 mesh, conditioned with 10 mol L-1 HCl. Zinc, nickel and copper were eluted in 10 mol L-1 HCl and 67Ga 3.5 mol L-1 HCl. The final product was obtained as 67Ga citrate. This work presents a new, fast, direct and efficient method for the chemical separation of 67Ga by thermal diffusion (heating of the target) combined with concentrated acetic acid extraction. Purification was performed by ion exchange chromatography. Natural zinc electrodeposition was performed on nickel/copper plates as substrate and the zinc deposits were adherent to the substrate, slightly shiny and uniform. The targets were irradiated with 26 MeV protons and integrated current of 10 μA.h. After irradiation, the targets were heated at 300 deg C for 2 hours and placed in contact with concentrated acetic acid for 1 hour. The average yield of extraction of 67Ga was (72 ± 10)%. This solution was evaporated and the residue was taken up in 0.5 mol L-1 NH4OH. The 67Ga was purified on cationic resin Dowex 50WX8 in NH4OH medium. The 67Ga recovery was (98 ± 2)%. This solution was evaporated and taken up in 0.1 mol L-1 HCl. The

  1. Burst and Principal Components Analyses of MEA Data Separates Chemicals by Class

    Science.gov (United States)

    Microelectrode arrays (MEAs) detect drug and chemical induced changes in action potential "spikes" in neuronal networks and can be used to screen chemicals for neurotoxicity. Analytical "fingerprinting," using Principal Components Analysis (PCA) on spike trains recorded from prim...

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

    Science.gov (United States)

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

    2016-02-01

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

  3. Carbon Dioxide Separation Technology: R&D Needs for the Chemical and Petrochemical Industries

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2007-11-01

    This report, the second in a series, is designed to summarize and present recommendations for improved CO2 separation technology for industrial processes. This report provides an overview of 1) the principal CO2 producing processes, 2) the current commercial separation technologies and 3) emerging adsorption and membrane technologies for CO2 separation, and makes recommendations for future research.

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

    Science.gov (United States)

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

    2016-05-01

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

  5. Aerosol assisted chemical vapor deposition using nanoparticle precursors: a route to nanocomposite thin films.

    Science.gov (United States)

    Palgrave, Robert G; Parkin, Ivan P

    2006-02-01

    Gold nanoparticle and gold/semiconductor nanocomposite thin films have been deposited using aerosol assisted chemical vapor deposition (CVD). A preformed gold colloid in toluene was used as a precursor to deposit gold films onto silica glass. These nanoparticle films showed the characteristic plasmon absorption of Au nanoparticles at 537 nm, and scanning electron microscopic (SEM) imaging confirmed the presence of individual gold particles. Nanocomposite films were deposited from the colloid concurrently with conventional CVD precursors. A film of gold particles in a host tungsten oxide matrix resulted from co-deposition with [W(OPh)(6)], while gold particles in a host titania matrix resulted from co-deposition with [Ti(O(i)Pr)(4)]. The density of Au nanoparticles within the film could be varied by changing the Au colloid concentration in the original precursor solution. Titania/gold composite films were intensely colored and showed dichromism: blue in transmitted light and red in reflected light. They showed metal-like reflection spectra and plasmon absorption. X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis confirmed the presence of metallic gold, and SEM imaging showed individual Au nanoparticles embedded in the films. X-ray diffraction detected crystalline gold in the composite films. This CVD technique can be readily extended to produce other nanocomposite films by varying the colloids and precursors used, and it offers a rapid, convenient route to nanoparticle and nanocomposite thin films. PMID:16448130

  6. Metal-assisted chemical etching of Ge surface and its effect on photovoltaic devices

    Science.gov (United States)

    Lee, Seunghyo; Choo, Hyeokseong; Kim, Changheon; Oh, Eunseok; Seo, Dongwan; Lim, Sangwoo

    2016-05-01

    Ge surfaces were etched by means of metal-assisted chemical etching (MaCE). The behavior of the MaCE reaction in diluted H2O2 was compared with that of a conventional etchant of HF/H2O2/H2O mixture (FPM). Herein we first report that a pyramidal structure on Ge (0 0 1) can be prepared by MaCE in dilute H2O2 solution, without the use of HF. Contrastingly, an octagonal trench structure was prepared by 4/5/1 FPM treatment of Ge (0 0 1) surface. This octagonal structure consisted of a square base, four large facets connected to the base, and other four small facets adjacent to the four large facets, which were considered to be (0 0 1), {1 1 0}, and {1 1 1}, respectively. The octagonal trench was formed as a result of the difference in etch rate of Ge depending on the orientation: {1 0 0} > {1 1 0} > {1 1 1}. Ge surfaces treated by MaCE exhibited improved solar cell efficiency due to their improved light absorption, which led to significant increases in the cells' short circuit current and fill factor. The results suggest that optimized MaCE procedures can be an effective method to improve the performance of Ge-based photovoltaic devices.

  7. Ultralight boron nitride aerogels via template-assisted chemical vapor deposition

    Science.gov (United States)

    Song, Yangxi; Li, Bin; Yang, Siwei; Ding, Guqiao; Zhang, Changrui; Xie, Xiaoming

    2015-05-01

    Boron nitride (BN) aerogels are porous materials with a continuous three-dimensional network structure. They are attracting increasing attention for a wide range of applications. Here, we report the template-assisted synthesis of BN aerogels by catalyst-free, low-pressure chemical vapor deposition on graphene-carbon nanotube composite aerogels using borazine as the B and N sources with a relatively low temperature of 900 °C. The three-dimensional structure of the BN aerogels was achieved through the structural design of carbon aerogel templates. The BN aerogels have an ultrahigh specific surface area, ultralow density, excellent oil absorbing ability, and high temperature oxidation resistance. The specific surface area of BN aerogels can reach up to 1051 m2 g-1, 2-3 times larger than the reported BN aerogels. The mass density can be as low as 0.6 mg cm-3, much lower than that of air. The BN aerogels exhibit high hydrophobic properties and can absorb up to 160 times their weight in oil. This is much higher than porous BN nanosheets reported previously. The BN aerogels can be restored for reuse after oil absorption simply by burning them in air. This is because of their high temperature oxidation resistance and suggests broad utility as water treatment tools.

  8. Gas phase chemistry during electron assisted chemical vapor deposition (EACVD) of diamond films

    International Nuclear Information System (INIS)

    Diamond films were deposited in electron assisted chemical vapor deposition (EACVD) reactor using two source mixtures of CH4-H2 and C2H5OH-H2, respectively. The plasma gas composition during diamond growing was investigated in situ using optical emission spectroscopy (OES). In two cases of C2H2OH-H2 and CH4-H2 plasma, it was shown that CH and CH+ were all important precursor species in the diamond deposition reaction while the yields of poor diamond films corresponded to the presence of the C2 emission line. The difference between these two cases was that some oxygen-containing species (CH2O, CHO and O2) were detected in the C2H5OH-H2 plasma. The presence of these products may maintain the quality of the deposited diamond films while increasing carbon source concentration, and the growth rate was thus enhanced. These results imply that the increase in the growth rate of diamond film using C2H5OH-H2 mixture is primarily due to a change in gas phase environment

  9. Hybrid chemical vapour and nanoceramic aerosol assisted deposition for multifunctional nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, Michael E.A.; Dunnill, Charles W.; Goodall, Josie; Darr, Jawwad A.; Binions, Russell, E-mail: uccarbi@ucl.ac.uk

    2011-07-01

    Hybrid atmospheric pressure chemical vapour and aerosol assisted deposition via the reaction of vanadium acetylacetonate and a suspension of preformed titanium dioxide or cerium dioxide nanoparticles, led to the production of vanadium dioxide nanocomposite thin films on glass substrates. The preformed nanoparticle oxides used for the aerosol were synthesised using a continuous hydrothermal flow synthesis route involving the rapid reaction of a metal salt solution with a flow of supercritical water in a flow reactor. Multifunctional nanocomposite thin films from the hybrid deposition process were characterised using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The functional properties of the films were evaluated using variable temperature optical measurements to assess thermochromic behaviour and methylene blue photodecolourisation experiments to assess photocatalytic activity. The tests show that the films are multifunctional in that they are thermochromic (having a large change in infra-red reflectivity upon exceeding the thermochromic transition temperature) and have significant photocatalytic activity under irradiation with 254 nm light.

  10. Chemical vapor deposition graphene transfer process to a polymeric substrate assisted by a spin coater

    Science.gov (United States)

    Kessler, Felipe; da Rocha, Caique O. C.; Medeiros, Gabriela S.; Fechine, Guilhermino J. M.

    2016-03-01

    A new method to transfer chemical vapor deposition graphene to polymeric substrates is demonstrated here, it is called direct dry transfer assisted by a spin coater (DDT-SC). Compared to the conventional method DDT, the improvement of the contact between graphene-polymer due to a very thin polymeric film deposited by spin coater before the transfer process prevented air bubbles and/or moisture and avoided molecular expansion on the graphene-polymer interface. An acrylonitrile-butadiene-styrene copolymer, a high impact polystyrene, polybutadiene adipate-co-terephthalate, polylactide acid, and a styrene-butadiene-styrene copolymer are the polymers used for the transfers since they did not work very well by using the DDT process. Raman spectroscopy and optical microscopy were used to identify, to quantify, and to qualify graphene transferred to the polymer substrates. The quantity of graphene transferred was substantially increased for all polymers by using the DDT-SC method when compared with the DDT standard method. After the transfer, the intensity of the D band remained low, indicating low defect density and good quality of the transfer. The DDT-SC transfer process expands the number of graphene applications since the polymer substrate candidates are increased.

  11. Preparation of 99Mo from the 100Mo(γ,n) reaction and chemical separation of 99mTc

    International Nuclear Information System (INIS)

    The radionuclide 99Mo has been prepared by 100Mo(γ, n) reaction using two types of natural molybdenum compound (molybdenum trioxide and zirconium molybdate gel) with the bremsstrahlung end-point energies of 10 and 15 MeV. After the equilibrium, 99mTc was separated as NaTcO4 from the irradiated samples using two different chemical procedures to examine the chemical yield. The separated Na[99mTc]TcO4 from the ZrMo gel has the 99Mo breakthrough of <10-4 %, radiochemical purity >99 % as well as chemical impurities of Al, Mo and Zr < 10 ppm. The estimation of 99Mo and 99mTc was done by using off-line c-ray spectrometric technique. The chemical yield of the separated 99mTc from the dissolved molybdenum trioxide is 70.7-75.2 %, whereas in the undissolved zirconium molybdate gel, it is 19.1-43 %. The second method is preferable because it is user friendly in hospital radiopharmacy throughout the shelf-life. (author)

  12. Chemical Vapor Deposition of MoS2: Insight Into the Growth Mechanism by Separated Gas Flow Experiments.

    Science.gov (United States)

    Yanase, Takashi; Watanabe, Sho; Weng, Mengting; Nagahama, Taro; Shimada, Toshihiro

    2016-04-01

    We report detailed experiments on chemical vapor deposition of an atomic' layer semiconductor MoS2. We developed a new type of CVD system in which MoO3 and S sources are separately supplied to the substrates. It has become possible to precisely control the supply of the materials separately in the order of seconds. Raman and XPS analysis of the films grown under various conditions revealed that the initially obtained films are S-deficient and complete stoichiometry is reached after several minutes under S vapor flow. PMID:27451608

  13. Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste

    International Nuclear Information System (INIS)

    Highlights: ► Separation of Pb and Zn from Fe and Cu in ash-melting of municipal solid waste. ► Molar ratio of Cl to Na and K in fly ash affected the metal-separation efficiency. ► The low molar ratio and a non-oxidative atmosphere were better for the separation. - Abstract: In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of the ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu

  14. Fluorinion transfer in silver-assisted chemical etching for silicon nanowires arrays

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Tianyu; Xu, Youlong, E-mail: ylxu@mail.xjtu.edu.cn; Zhang, Zhengwei; Mao, Shengchun

    2015-08-30

    Graphical abstract: - Highlights: • How Ag transfers F{sup −} to the adjacent Si atom was investigated and deduced by DFT at atomic scale. • Three-electrode CV tests proved the transferring function of Ag in the etching reaction. • Uniform SiNWAs were fabricated on unpolished silicon wafers with KOH pretreatment. - Abstract: Uniform silicon nanowires arrays (SiNWAs) were fabricated on unpolished rough silicon wafers through KOH pretreatment followed by silver-assisted chemical etching (SACE). Density functional theory (DFT) calculations were used to investigate the function of silver (Ag) at atomic scale in the etching process. Among three adsorption sites of Ag atom on Si(1 0 0) surface, Ag(T4) above the fourth-layer surface Si atoms could transfer fluorinion (F{sup −}) to adjacent Si successfully due to its stronger electrostatic attraction force between Ag(T4) and F{sup −}, smaller azimuth angle of F−Ag(T4)−Si, shorter bond length of F−Si compared with F−Ag. As F{sup −} was transferred to adjacent Si by Ag(T4) one by one, the Si got away from the wafer in the form of SiF{sub 4} when it bonded with enough F{sup −} while Ag(T4) was still attached onto the Si wafer ready for next transfer. Cyclic voltammetry tests confirmed that Ag can improve the etching rate by transferring F{sup −} to Si.

  15. Nanoscale coatings of tungsten by radio frequency plasma assisted chemical vapor deposition on graphite

    International Nuclear Information System (INIS)

    Future thermonuclear fusion reactors including ITER are heading towards full scale operations with tungsten being the material for the divertor, limiter and probably the first wall too. Tungsten has several superior properties over its low Z competitors in terms of higher melting point, lower sputtering yield, low fuel retention (D - T) etc. So far, fusion experimentalists have gained enough experience and have rich databases with carbon as its first wall as well as target materials in tokamaks. However, database for tungsten line radiation in variety of plasmas i.e. basic laboratory scale to high density and high temperature plasmas is rare and this requires immediate attention to construct a database with experimental evidences. Such studies are not limited to only large scale fusion reactors but small and medium scale toroidally confined devices can be suitably utilized. Present day tokamaks are now switching to plasma facing components made up of tungsten. As the complete replacement of the wall and target materials from carbon to tungsten in existing tokamaks is challenging and time consuming exercise, tungsten coatings on selected target materials remains a very feasible option for the purpose. This paper will present the development of indigenous tungsten coating reactor which has successfully produced tungsten coated graphite tiles of sample dimensions. The tungsten coated graphite tiles are produced by RF plasma assisted chemical vapor deposition of tungsten on graphite substrates. The RF plasma is produced with 60 - 100 W power and tungsten nano ions are produced by dissociating the precursor gas tungsten hexa-fluoride (WF6) in sufficient hydrogen background. Further, challenges in handling WF6 plasma at high pressures and in-situ spectroscopy results during the coating process will be presented. (author)

  16. Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

    International Nuclear Information System (INIS)

    Silicon (Si) thin films were produced using an aerosol assisted atmospheric pressure chemical vapor deposition technique with liquid hydrosilane precursors cyclopentasilane (CPS, Si5H10) and cyclohexasilane (CHS, Si6H12). Thin films were deposited at temperatures between 300 and 500 °C, with maximum observed deposition rates of 55 and 47 nm/s for CPS and CHS, respectively, at 500 °C. Atomic force microscopic analyses of the films depict smooth surfaces with roughness of 4–8 nm. Raman spectroscopic analysis indicates that the Si films deposited at 300 °C and 350 °C consist of a hydrogenated amorphous Si (a-Si:H) phase while the films deposited at 400, 450, and 500 °C are comprised predominantly of a hydrogenated nanocrystalline Si (nc-Si:H) phase. The wide optical bandgaps of 2–2.28 eV for films deposited at 350–400 °C and 1.7–1.8 eV for those deposited at 450–500 °C support the Raman data and depict a transition from a-Si:H to nc-Si:H. Films deposited at 450 oC possess the highest photosensitivity of 102–103 under AM 1.5G illumination. Based on the growth model developed for other silanes, we suggest a mechanism that governs the film growth using CPS and CHS. - Highlights: • Si films via AA-APCVD are realized using cyclopentasilane (CPS) and cyclohexasilane (CHS). • Low activation energies of CPS and CHS allow Si thin films at low temperatures (300 °C). • High growth rates of 47–55 nm/s were obtained at 500 °C • Near device quality Si thin films with 2–3 orders of photosensitivity • Si thin films via AA-APCVD are amenable to continuous roll-to-roll manufacturing

  17. Chemical separation for the burnup determination of the U3Si/Al spent fuels

    International Nuclear Information System (INIS)

    The separation of U, Pu, and Nd for the burnup determination of the U3Si/Al spent fuel samples has been studied. The preliminary experiments were carried out with the simulated spent fuel solution. The solutions were prepared by adding of fission product elements to unirradiated U3Si/Al fuel samples. The fuel samples were dissolved in 6 M HNO3, 6 M HNO3 using mercury catalyst, or applying a mixture of HCl and HNO3 without any catalyst. All dissolved fuel solutions contained a small amount of a residue(silica). The trace silica reprecipitated from the fuel solutions taken for the separation was dissolved in HF and removed by subsequent evaporating to dryness. The separation of U and fission product elements from the various sample solutions was achieved by two sequential anion exchange resin separation procedures. The U, Pu and Nd can be purely isolated from the sample solutions with a large excess of Al by this chromatographic procedures. The dissolution and separation procedure used in this experiment were applied for burnup determination of real U3Si/Al spent fuels from HANARO reactor

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

    OpenAIRE

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

    2011-01-01

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

  19. Triangle pore arrays fabricated on Si (111) substrate by sphere lithography combined with metal-assisted chemical etching and anisotropic chemical etching

    Science.gov (United States)

    Asoh, Hidetaka; Fujihara, Kosuke; Ono, Sachiko

    2012-07-01

    The morphological change of silicon macropore arrays formed by metal-assisted chemical etching using shape-controlled Au thin film arrays was investigated during anisotropic chemical etching in tetramethylammonium hydroxide (TMAH) aqueous solution. After the deposition of Au as the etching catalyst on (111) silicon through a honeycomb mask prepared by sphere lithography, the specimens were etched in a mixed solution of HF and H2O2 at room temperature, resulting in the formation of ordered macropores in silicon along the [111] direction, which is not achievable by conventional chemical etching without a catalyst. In the anisotropic etching in TMAH, the macropores changed from being circular to being hexagonal and finally to being triangular, owing to the difference in etching rate between the crystal planes.

  20. Evaluation of possible physical-chemical processes that might lead to separations of actinides in ORNL waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Del Cul, G.D.; Toth, L.M.; Bond, W.D.; Dai, S.

    1997-09-01

    The concern that there might be some physical-chemical process which would lead to a separation of the poisoning actinides ({sup 232}Th, {sup 238}U) from the fissionable ones ({sup 239}Pu, {sup 235}U) in waste storage tanks at Oak Ridge National Laboratory has led to a paper study of potential separations processes involving these elements. At the relatively high pH values (>8), the actinides are normally present as precipitated hydroxides. Mechanisms that might then selectively dissolve and reprecipitate the actinides through thermal processes or additions of reagents were addressed. Although redox reactions, pH changes, and complexation reactions were all considered, only the last type was regarded as having any significant probability. Furthermore, only carbonate accumulation, through continual unmonitored air sparging of the tank contents, could credibly account for gross transport and separation of the actinide components. From the large amount of equilibrium data in the literature, concentration differences in Th, U, and Pu due to carbonate complexation as a function of pH have been presented to demonstrate this phenomenon. While the carbonate effect does represent a potential separations process, control of long-term air sparging and solution pH, accompanied by routine determinations of soluble carbonate concentration, should ensure that this separations process does not occur.

  1. Evaluation of possible physical-chemical processes that might lead to separations of actinides in ORNL waste tanks

    International Nuclear Information System (INIS)

    The concern that there might be some physical-chemical process which would lead to a separation of the poisoning actinides (232Th, 238U) from the fissionable ones (239Pu, 235U) in waste storage tanks at Oak Ridge National Laboratory has led to a paper study of potential separations processes involving these elements. At the relatively high pH values (>8), the actinides are normally present as precipitated hydroxides. Mechanisms that might then selectively dissolve and reprecipitate the actinides through thermal processes or additions of reagents were addressed. Although redox reactions, pH changes, and complexation reactions were all considered, only the last type was regarded as having any significant probability. Furthermore, only carbonate accumulation, through continual unmonitored air sparging of the tank contents, could credibly account for gross transport and separation of the actinide components. From the large amount of equilibrium data in the literature, concentration differences in Th, U, and Pu due to carbonate complexation as a function of pH have been presented to demonstrate this phenomenon. While the carbonate effect does represent a potential separations process, control of long-term air sparging and solution pH, accompanied by routine determinations of soluble carbonate concentration, should ensure that this separations process does not occur

  2. The use of a hot cyclone for separation of heavy metals during combustion, evaluation by chemical equilibrium calculations

    International Nuclear Information System (INIS)

    This degree-project is a part of a project financed by the European Communities non Nuclear energy program. The aim of the project is to reach a sustainable use of biofuels as energy source. A requirement for sustainable use of biomass fuel in combustion and gasification plants is that the ash produced can be recycled back to the forest and farmlands in a safe and controlled way. Recycling is important because most of the nutrients (Ca, Mg, P, Na and K) are ending up in the ash. However, the ashes also contain heavy metals and organic pollutants that should not be recycled. To solve this problem, a new technique for separation of the heavy metals during combustion is under development. This technique builds on evaporation of heavy metals and particle separation with a hot cyclone. The idea is that the heavy metal will pass the cyclone as gas species while the nutrients will be separated in the cyclone from the flue gas. The heavy metals are then collected in the more efficient cleaning device downstream in the process. In the present study, the technique has been evaluated by chemical equilibrium calculations and the results were compared with some previously performed full-scale experiments. The results show that by this technique a separation of Cd and Pb will be possible. Concerning the elements As, Cu and Cr, it may be possible to separate them to some extent while the element Ni and V will not be separated. At least 60-70% of Na and K and 90% of Ca, Mg and P will be separated in the cyclone 21 refs, 12 figs, 2 tabs

  3. Proceedings of the 23. International Symposium on Physico-Chemical Methods of Separation - Ars Separatoria 2008

    International Nuclear Information System (INIS)

    Annual symposia '' Ars Separatoria '' offer the scientists and engineers information on the latest achievements in the separation sciences. In 2008 participants presented 6 lectures, 16 short lectures and 74 posters. Of special interest were results obtained using solvent extraction and ion exchange methods

  4. Separation of 15N by chemical exchange in NO, NO2 - HNO3 system under pressure

    International Nuclear Information System (INIS)

    The basic isotopic exchange reaction is responsible for the separation of 15N in the Nitrox system that between gaseous nitrogen oxides and aqueous nitric acid with a single stage separation factor α = 1.055 for 10M nitric acid, at 25 deg C and atmospheric pressure takes place. In order to know what happens in 15N separation at higher pressure, when the isotopic transport between two phases is improved, a stainless steel laboratory experimental plant with a 1000 mm long x 18 mm i.d. column, packed with triangular wire springs 1.8 x 1.8 x 0.2 mm2, was utilised. At 1.5 atm (absolute), and 2.36 ml x cm-2 x min-1 flow rate HETP was 7% smaller than at atmospheric pressure and 1.5 times smaller flow rate. HETP at 3.14 ml x cm-2 x min-1 flow rate and 1.8 atm is practically equal with that obtained at atmospheric pressure and 2 times smaller flow rate. The operation of the 15N separation plant at 1.8 atm (absolute), instead of atmospheric pressure, will permit doubling of the 10M nitric acid flow rate and of 15N production of the given column. (author)

  5. Polyaniline/polybenzimidazole blends: characterisation of its physico-chemical properties and gas separation behaviour

    Czech Academy of Sciences Publication Activity Database

    Giel, Verena; Kredatusová, Jana; Trchová, Miroslava; Brus, Jiří; Žitka, Jan; Peter, Jakub

    2016-01-01

    Roč. 77, April (2016), s. 98-113. ISSN 0014-3057 R&D Projects: GA ČR(CZ) GPP106/12/P643 Institutional support: RVO:61389013 Keywords : gas separation * gas sorption * gas permeation Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.005, year: 2014

  6. A differential viscosity detector for use in miniaturized chemical separation systems

    NARCIS (Netherlands)

    Blom, Marko T.; Chmela, Emil; Heyden, van der Frank H.J.; Oosterbroek, R. Edwin; Tijssen, Robert; Elwenspoek, Miko; Berg, van den Albert

    2005-01-01

    We present a micromachined differential viscosity detector suitable for integration into an on-chip hydrodynamic chromatography system. The general design, however, is applicable to any liquid chromatography system that is used for separation of polymers. The micromachined part of the detector consi

  7. Proceedings of the 22. International Symposium on Physico-Chemical Methods of Separation - Ars Separatoria 2007

    International Nuclear Information System (INIS)

    Annual symposia '' Ars Separatoria '' offer the scientists and engineers information on the latest achievements in the separation sciences. In 2007 participants presented 9 plenary lectures, 15 communications and 45 posters. Of special interest were results obtained using solvent extraction and ion exchange methods

  8. Proceedings of the 24. International Symposium on Physico-Chemical Methods of Separation - Ars Separatoria 2009

    International Nuclear Information System (INIS)

    Annual symposia '' Ars Separatoria '' offer the scientists and engineers information on the latest achievements in the separation sciences. In 2009 participants presented 9 lectures, 16 short lectures and 63 posters. Of special interest were results obtained using solvent extraction and ion exchange methods

  9. Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Guruvenket, Srinivasan, E-mail: guruvenket.srinivasan@ndsu.edu [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Hoey, Justin M.; Anderson, Kenneth J.; Frohlich, Matthew T.; Sailer, Robert A. [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Boudjouk, Philip [Center for Nanoscale Energy Related Materials, 1715 NDSU Research Park Drive N, North Dakota State University, Fargo, ND 58102 (United States); Department of Chemistry and Biochemistry, Ladd-Dunbar Hall, North Dakota State University, Fargo, ND 58102 (United States)

    2015-08-31

    Silicon (Si) thin films were produced using an aerosol assisted atmospheric pressure chemical vapor deposition technique with liquid hydrosilane precursors cyclopentasilane (CPS, Si{sub 5}H{sub 10}) and cyclohexasilane (CHS, Si{sub 6}H{sub 12}). Thin films were deposited at temperatures between 300 and 500 °C, with maximum observed deposition rates of 55 and 47 nm/s for CPS and CHS, respectively, at 500 °C. Atomic force microscopic analyses of the films depict smooth surfaces with roughness of 4–8 nm. Raman spectroscopic analysis indicates that the Si films deposited at 300 °C and 350 °C consist of a hydrogenated amorphous Si (a-Si:H) phase while the films deposited at 400, 450, and 500 °C are comprised predominantly of a hydrogenated nanocrystalline Si (nc-Si:H) phase. The wide optical bandgaps of 2–2.28 eV for films deposited at 350–400 °C and 1.7–1.8 eV for those deposited at 450–500 °C support the Raman data and depict a transition from a-Si:H to nc-Si:H. Films deposited at 450 {sup o}C possess the highest photosensitivity of 10{sup 2}–10{sup 3} under AM 1.5G illumination. Based on the growth model developed for other silanes, we suggest a mechanism that governs the film growth using CPS and CHS. - Highlights: • Si films via AA-APCVD are realized using cyclopentasilane (CPS) and cyclohexasilane (CHS). • Low activation energies of CPS and CHS allow Si thin films at low temperatures (300 °C). • High growth rates of 47–55 nm/s were obtained at 500 °C • Near device quality Si thin films with 2–3 orders of photosensitivity • Si thin films via AA-APCVD are amenable to continuous roll-to-roll manufacturing.

  10. Effect of Separation Method on Chemical Composition and Insecticidal Activity of Lamiaceae Isolates

    Czech Academy of Sciences Publication Activity Database

    Sajfrtová, Marie; Sovová, Helena; Karban, Jindřich; Rochová, Kristina; Pavela, R.; Barnet, M.

    2013-01-01

    Roč. 47, MAY (2013), s. 69-77. ISSN 0926-6690 R&D Projects: GA MŠk 2B06049; GA TA ČR TA01010578 Institutional support: RVO:67985858 Keywords : supercritical fluid extraction * iInsecticidal activity * lamiaceae Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.208, year: 2013

  11. Interdisciplinary Learning for Chemical Engineering Students from Organic Chemistry Synthesis Lab to Reactor Design to Separation

    Science.gov (United States)

    Armstrong, Matt; Comitz, Richard L.; Biaglow, Andrew; Lachance, Russ; Sloop, Joseph

    2008-01-01

    A novel approach to the Chemical Engineering curriculum sequence of courses at West Point enabled our students to experience a much more realistic design process, which more closely replicated a real world scenario. Students conduct the synthesis in the organic chemistry lab, then conduct computer modeling of the reaction with ChemCad and…

  12. A differential viscosity detector for use in miniaturized chemical separation systems

    OpenAIRE

    Blom, Marko T.; Chmela, Emil; Heyden; Oosterbroek, R. Edwin; Tijssen, Robert; Elwenspoek, Miko; Berg, van den, W.

    2005-01-01

    We present a micromachined differential viscosity detector suitable for integration into an on-chip hydrodynamic chromatography system. The general design, however, is applicable to any liquid chromatography system that is used for separation of polymers. The micromachined part of the detector consists of a fluidic Wheatstone bridge and a low hydraulic capacitance pressure sensor of which the pressure sensing is based on optical detection of a membrane deflection. The stand-alone sensor shows...

  13. Chemically Compatible Sacrificial Layer-Assisted Lift-Off Patterning Method for Fabrication of Organic Light-Emitting Displays

    Science.gov (United States)

    Choi, Wonsuk; Kim, Min-Hoi; Lee, Sin-Doo

    2011-08-01

    We developed a generic platform to pattern combinatorial functional layers composed of different classes of organic materials using a repetitive lift-off method based on a chemically compatible sacrificial layer (SL) for organic light-emitting diodes (OLEDs). The essential features come from the chemically compatible SL of a fluorous-polymer that can be generated by laser-inscription or transfer-printing. The precise registration of lateral patterns of different materials was achieved on a single substrate through a series of SL-assisted lift-off processes. The chemical compatibility of the SL and the stability of the light-emitting characteristics were shown in a fluorous-solvent treated monochrome OLEDs.

  14. Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples

    Science.gov (United States)

    Miyazaki, Takashi; Vaglarov, Bogdan Stefanov; Takei, Masakazu; Suzuki, Masahiro; Suzuki, Hiroaki; Ohsawa, Kouzou; Chang, Qing; Takahashi, Toshiro; Hirahara, Yuka; Hanyu, Takeshi; Kimura, Jun-Ichi; Tatsumi, Yoshiyuki

    A fully automated open-column resin-bed chemical-separation system, named COLUMNSPIDER, has been developed. The system consists of a programmable micropipetting robot that dispenses chemical reagents and sample solutions into an open-column resin bed for elemental separation. After the initial set up of resin columns, chemical reagents, and beakers for the separated chemical components, all separation procedures are automated. As many as ten samples can be eluted in parallel in a single automated run. Many separation procedures, such as radiogenic isotope ratio analyses for Sr and Nd, involve the use of multiple column separations with different resin columns, chemical reagents, and beakers of various volumes. COLUMNSPIDER completes these separations using multiple runs. Programmable functions, including the positioning of the micropipetter, reagent volume, and elution time, enable flexible operation. Optimized movements for solution take-up and high-efficiency column flushing allow the system to perform as precisely as when carried out manually by a skilled operator. Procedural blanks, examined for COLUMNSPIDER separations of Sr, Nd, and Pb, are low and negligible. The measured Sr, Nd, and Pb isotope ratios for JB-2 and Nd isotope ratios for JB-3 and BCR-2 rock standards all fall within the ranges reported previously in high-accuracy analyses. COLUMNSPIDER is a versatile tool for the efficient elemental separation of igneous rock samples, a process that is both labor intensive and time consuming.

  15. Separation of stable isotopes of alkali and alkaline earth metals in chemical exchange systems with crown ethers

    International Nuclear Information System (INIS)

    Chemical isotope exchange in two-phase water - organic systems Men+ (water) - MeLn+ (org), where Me = Li, Ca, K, Mg; L = crown ethers with 5 to 6 oxygen atoms in macrocyclic ring; org = CHCl3, CH2Cl2 has been studied. The process of isotope separation has been realized by extraction chromatography. The chromatographic column contained a fixed aqueous phase. The organic solution of metal complex with crown ether was eluted through the column. On contact with the fixed aqueous phase in the course of chromatography, metal salt reextraction occurred and interphase isotope exchange between aqueous and organic phases resulted. Isotope separation factors in these systems were in the range of: 1.0032 - 1.020 (6Li/7Li), 1.0016 - 1.0038 (40Ca/44Ca), 1.0007 - 1.0011 (39K/41K), 1.0014 - 1.0044 (24Mg/26Mg). The theoretical model has been proposed to interpret the high separation factors in crown ether extraction systems. According to this model, the potential in such systems has a very flat bottom. This type of potential results in weakening the force field and decreasing of β-factor (i.e., (s/s')f) in spite of comparatively high energy of complexation. This model can interpret both high separation factors and their strong dependence on the type of crown ether. (author)

  16. The Gaia-ESO Survey: Separating disk chemical substructures with cluster models. Evidence of a separate evolution in the metal-poor thin disk

    Science.gov (United States)

    Rojas-Arriagada, A.; Recio-Blanco, A.; de Laverny, P.; Schultheis, M.; Guiglion, G.; Mikolaitis, Š.; Kordopatis, G.; Hill, V.; Gilmore, G.; Randich, S.; Alfaro, E. J.; Bensby, T.; Koposov, S. E.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Jofré, P.; Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S.; Chiappini, C.

    2016-02-01

    Context. Recent spectroscopic surveys have begun to explore the Galactic disk system on the basis of large data samples, with spatial distributions sampling regions well outside the solar neighborhood. In this way, they provide valuable information for testing spatial and temporal variations of disk structure kinematics and chemical evolution. Aims: The main purposes of this study are to demonstrate the usefulness of a rigorous mathematical approach to separate substructures of a stellar sample in the abundance-metallicity plane, and provide new evidence with which to characterize the nature of the metal-poor end of the thin disk sequence. Methods: We used a Gaussian mixture model algorithm to separate in the [Mg/Fe] vs. [Fe/H] plane a clean disk star subsample (essentially at RGC -0.25 dex) highlight a change in the slope at solar metallicity. This holds true at different radial regions of the Milky Way. The distribution of Galactocentric radial distances of the metal-poor part of the thin disk ([Fe/H] levels might be due to their origin from gas pre-enriched by outflows from the thick disk or the inner halo. The smooth trends of their properties (their spatial distribution with respect to the plane, in particular) with [Fe/H] and [Mg/Fe] suggested by the data indicates a quiet dynamical evolution, with no relevant merger events. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council.

  17. Standardization of 90Sr+ 90Y by Means of a Chemical Separation

    International Nuclear Information System (INIS)

    Precipitation of strontium in a 90Sr + 90Y solution by fuming nitric acid offers an opportunity of preparing sources in which, at first, one of the two activities is much weaker than the other. If the initially weaker activity is known, the other can be calculated from the count rates measured at two suitably chosen times. A procedure is developed which quantitatively connects the specific activity of the mother solution with that of the solution dispensed onto the source mounts. The main difficulty is encountered in determining the initial 90Y activity of the 90Sr-enriched sources. Since a high degree of separation can hardly be achieved in a single precipitation, the 90Y content of the supernate has to be determined as well. If the 90Y is distributed uniformly after the precipitation, the corresponding 90Y activity retained by the precipitate can be calculated easily. Yet the 90Y concentration sometimes deviated significantly from uniformity. A way of partially circumventing this difficulty is pointed out. Exact formulae are derived expressing the activities in terms of the count rates observed at different times. A full account of the various sources of error is given; the spread of the results obtained is compatible with that expected. The specific activity of the mother solution is calculated with 15 sources prepared from four independent precipitations. The mother solution had already been calibrated by 24 laboratories taking part in an international comparison organized by the Bipm in 1964. The agreement is well within the limits of error. Although the separation method described here is too laborious to be used in routine work, it merits some attention as an independent method of standardizing a pure β-emitter by β-counting alone, without using any extrapolation. The accuracy reached compares favourably with that of currently used methods. The separation method may be superior to others when a 90Sr + 90Y solution with a high carrier content is to be

  18. Development of Geothermally Assisted Process for Production of Liquid Fuels and Chemicals from Wheat Straw

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, V.G.; Linden, J.C.; Moreira, A.R.; Lenz, T.G.

    1981-06-01

    Recently there has been much interest in developing processes for producing liquid fuels from renewable resources. The most logical long term approach in terms of economics derives the carbohydrate substrate for fermentation from the hydrolysis of cellulosic crop and forest residues rather than from grains or other high grade food materials (1,2). Since the presence of lignin is the main barrier to the hydrolysis of cellulose from lignocellulosic materials, delignification processes developed by the wood pulping industry have been considered as possible prehydrolysis treatments. The delignification process under study in our laboratory is envisioned as a synthesis of two recently developed pulping processes. In the first step, called autohydrolysis, hot water is used directly to solubilize hemicellulose and to depolymerize lignin (3). Then, in a second step known as organosolv pulping (4), the autohydrolyzed material is extracted with aqueous alcohol. A s shown in Figure 1, this process can separate the original lignocellulosic material into three streams--hemicellulose in water, lignin in aqueous alcohol, and a cellulose pulp. Without further mechanical milling, delignified cellulose can be enzymatically hydrolyzed at 45-50 C to greater than 80% theoretical yield of glucose using fungal cellulases (5, 6). The resulting glucose syrup can then be fermented by yeast to produce ethanol or by selected bacteria to produce acetone and butanol or acetic and propionic acids (7). One objection to such a process, however, is the large energy input that is required. In order to extend our supplies of liquid fuels and chemicals, it is important that the use of fossil fuels in any lignocellulosic conversion process be minimized. The direct use of geothermal hot water in carrying out the autohydrolysis and extraction operations, therefore, seems especially attractive. On the one hand, it facilitates the conversion of non-food biomass to fuels and chemicals without wasting fossil

  19. Designing learning curves for carbon capture based on chemical absorption according to the minimum work of separation

    International Nuclear Information System (INIS)

    Highlights: • This work defines the minimum work of separation (MWS) for a capture process. • Findings of the analysis indicated a MWS of 0.158 GJ/t for post-combustion. • A review of commercially available processes based on chemical absorption was made. • A review of learning models was conducted, with the addition on a novel model. • A learning curve for post-combustion carbon capture was successfully designed. - Abstract: Carbon capture is one of the most important alternatives for mitigating greenhouse gas emissions in energy facilities. The post-combustion route based on chemical absorption with amine solvents is the most feasible alternative for the short term. However, this route implies in huge energy penalties, mainly related to the solvent regeneration. By defining the minimum work of separation (MWS), this study estimated the minimum energy required to capture the CO2 emitted by coal-fired thermal power plants. Then, by evaluating solvents and processes and comparing it to the MWS, it proposes the learning model with the best fit for the post-combustion chemical absorption of CO2. Learning models are based on earnings from experience, which can include the intensity of research and development. In this study, three models are tested: Wright, DeJong and D and L. Findings of the thermochemical analysis indicated a MWS of 0.158 GJ/t for post-combustion. Conventional solvents currently present an energy penalty eight times the MWS. By using the MWS as a constraint, this study found that the D and L provided the best fit to the available data of chemical solvents and absorption plants. The learning rate determined through this model is very similar to the ones found in the literature

  20. A new sampler for collecting separate dry and wet atmospheric depositions of trace organic chemicals

    Science.gov (United States)

    Waite, Don T.; Cessna, Allan J.; Gurprasad, Narine P.; Banner, James

    Studies conducted in Saskatchewan and elsewhere have demonstrated the atmospheric transport of agricultural pesticides and other organic contaminants and their deposition into aquatic ecosystems. To date these studies have focused on ambient concentrations in the atmosphere and in wet precipitation. To measure the dry deposition of organic chemicals, a new sampler was designed which uses a moving sheet of water to passively trap dry particles and gasses. The moving sheet of water drains into a reservoir and, during recirculation through the sampler, is passed through an XAD-2 resin column which adsorbs the trapped organic contaminants. All surfaces which contact the process water are stainless steel or Teflon. Chemicals collected can be related to airborne materials depositing into aquatic ecosystems. The sampler has received a United States patent (number 5,413,003 - 9 May 1996) with the Canadian patent pending. XAD-2 resin adsorption efficiencies for 10 or 50 μg fortifications of ten pesticides ranged from 76% for atrazine (2-chloro-4-ethylamino-6-isopropylamino- S-triazine) to 110% for triallate [ S-(2,3,3-trichloro-2-phenyl)bis(1-methylethyl)carbamothioate], dicamba (2-methoxy-3,6-dichlorobenzoic acid) and toxaphene (chlorinated camphene mixture). Field testing using duplicate samplers showed good reproducibility and amounts trapped were consistent with those from high volume and bulk pan samplers located on the same site. Average atmospheric dry deposition rates of three chemicals, collected for 5 weeks in May and June, were: dicamba, 69 ng m -2 da -1; 2,4-D (2,4-dichlorophenoxyacetic acid), 276 ng m -2 da -1: and, γ-HCH ( γ-1, 2, 3, 4, 5, 6-hexachlorocyclohexane), 327 ng m -2 da -1.

  1. Chemical oxygen-iodine laser with atomic iodine generated in a separate reactor

    Czech Academy of Sciences Publication Activity Database

    Špalek, Otomar; Jirásek, Vít; Čenský, Miroslav; Kodymová, Jarmila; Picková, Irena; Jakubec, Ivo

    Bellingham: SPIE, 2006 - (Phipps, C.), 62611T/1-62611T/10. (Proceedings of SPIE. 6261). ISBN 0-8194-6326-4. ISSN 0277-786X. [High-Power Laser Ablation /6./. Taos, New Mexico (US), 07.05.2006-12.05.2006] R&D Projects: GA ČR GA202/05/0359 Grant ostatní: USAF EOARD(US) FA8655-02-M4040 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z40320502 Keywords : atomic iodine * atomic chlorine * atomic fluorine * chemical oxygen-iodine laser * COIL Subject RIV: BH - Optics, Masers, Lasers

  2. U.S. assistance in the destruction of Russia's chemical weapons

    OpenAIRE

    Mostoller, Eric Charles

    2000-01-01

    The thesis examines the present status of Russia's chemical weapons destruction program, which is to be implemented according to the 1993 Chemical Weapons Convention (CWC). It assesses the magnitude of the challenges in destroying the world's largest chemical weapons stockpile, which is located at seven sites in western Russia. It also evaluates the environmental and international security concerns posed by the conditions at these sites and the disastrous implications of a failure of this che...

  3. Development of metal-assisted chemical etching of silicon as a 3D nanofabrication platform

    Science.gov (United States)

    Hildreth, Owen James

    The considerable interest in nanomaterials and nanotechnology over the last decade is attributed to Industry's desire for lower cost, more sophisticated devices and the opportunity that nanotechnology presents for scientists to explore the fundamental properties of nature at near atomic levels. In pursuit of these goals, researchers around the world have worked to both perfect existing technologies and also develop new nano-fabrication methods; however, no technique exists that is capable of producing complex, 2D and 3D nano-sized features of arbitrary shape, with smooth walls, and at low cost. This in part is due to two important limitations of current nanofabrication methods. First, 3D geometry is difficult if not impossible to fabricate, often requiring multiple lithography steps that are both expensive and do not scale well to industrial level fabrication requirements. Second, as feature sizes shrink into the nano-domain, it becomes increasingly difficult to accurately maintain those features over large depths and heights. The ability to produce these structures affordably and with high precision is critically important to a number of existing and emerging technologies such as metamaterials, nano-fluidics, nano-imprint lithography, and more. To overcome these limitations, this study developed a novel and efficient method to etch complex 2D and 3D geometry in silicon with controllable sub-micron to nano-sized features with aspect ratios in excess of 500:1. This study utilized Metal-assisted Chemical Etching (MaCE) of silicon in conjunction with shape-controlled catalysts to fabricate structures such as 3D cycloids, spirals, sloping channels, and out-of-plane rotational structures. This study focused on taking MaCE from a method to fabricate small pores and silicon nanowires using metal catalyst nanoparticles and discontinuous thin films, to a powerful etching technology that utilizes shaped catalysts to fabricate complex, 3D geometry using a single lithography

  4. Fabrication of microchannels in single-crystal GaN by wet-chemical-assisted femtosecond-laser ablation

    International Nuclear Information System (INIS)

    We investigated micro- and nano-fabrication of wide band-gap semiconductor gallium nitride (GaN) using a femtosecond (fs) laser. Nanoscale craters were successfully formed by wet-chemical-assisted fs-laser ablation, in which the laser beam is focused onto a single-crystal GaN substrate in a hydrochloric acid (HCl) solution. This allows efficient removal of ablation debris produced by chemical reactions during ablation, resulting in high-quality ablation. However, a two-step processing method involving irradiation by a fs-laser beam in air followed by wet etching, distorts the shape of the crater because of residual debris. The threshold fluence for wet-chemical-assisted fs-laser ablation is lower than that for fs-laser ablation in air, which is advantageous for improving fabrication resolution since it reduces thermal effects. We have fabricated craters as small as 510 nm by using a high numerical aperture (NA) objective lens with an NA of 0.73. Furthermore, we have formed three-dimensional hollow microchannels in GaN by fs-laser direct-writing in HCl solution.

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

    Directory of Open Access Journals (Sweden)

    Yi-Hsiu Jen

    2014-01-01

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

  6. Fundamental study on separation and recovery technique of uranium from chemical trap fillers

    International Nuclear Information System (INIS)

    Various kinds of chemical traps are used for the removal of gaseous radionuclides, fluorine, etc in the process-off gas of uranium conversion facility or similar facilities. The spent fillers such as sodium fluoride (NaF), magnesium fluoride (CaF2), or activated alumina (Al2O3) from the chemical traps should be reused as useful materials, or converted into general industrial wastes so as to reduce the amount of radioactive waste, wherever possible. Molten salt technique can be considered as a feasible technique to be applied for the removal of radionuclides from the spent fillers. The mixed salt, NaF with sodium chloride (NaCl) was used in this experiment. The uranium concentration in the molten salt, pre-treatment condition, electrolytic temperature, current density, etc was used as parameters. Several fundamental experiments were carried out, and the obtained results were analyzed and evaluated. They indicate that the application of the molten salt technique is one of the potential methods for the removal of uranium from spent fillers. (author)

  7. Thermochromatographic method of separation of chemical elements in nuclear and radiochemistry

    International Nuclear Information System (INIS)

    The state of the art in the title field including vacuum thermochromatography and sublimatography is discussed. Thermochromatography has proven to be effective in studying properties of the transactinoid elements, in separation of products from spallation reactions, in the production of radionuclides for nuclear medicine. Applications of the method for the radiochemical activation analysis seem especially prospective. From the theoretical side, the dependence of deposition temperatures on experimental parameters is reasonably well understood for uniform surfaces while reported theoretical calculations of peak shapes have not yet been confronted with the experimental data extensively enough. The case of nonuniform surfaces is a problem for future research. Some interesting non-analytical applications of the method can be suggested, such as measuring the diffusion coefficients of the adsorbates and enthalpies and entropies of adsorption. (orig.)

  8. Growth and characterization of large, high quality single crystal diamond substrates via microwave plasma assisted chemical vapor deposition

    Science.gov (United States)

    Nad, Shreya

    Single crystal diamond (SCD) substrates can be utilized in a wide range of applications. Important issues in the chemical vapor deposition (CVD) of such substrates include: shrinking of the SCD substrate area, stress and cracking, high defect density and hence low electronic quality and low optical quality due to high nitrogen impurities. The primary objective of this thesis is to begin to address these issues and to find possible solutions for enhancing the substrate dimensions and simultaneously improving the quality of the grown substrates. The deposition of SCD substrates is carried out in a microwave cavity plasma reactor via the microwave plasma assisted chemical vapor deposition technique. The operation of the reactor was first optimized to determine the safe and efficient operating regime. By adjusting the matching of the reactor cavity with the help of four internal tuning length variables, the system was further matched to operate at a maximum overall microwave coupling efficiency of ˜ 98%. Even with adjustments in the substrate holder position, the reactor remains well matched with a coupling efficiency of ˜ 95% indicating good experimental performance over a wide range of operating conditions. SCD substrates were synthesized at a high pressure of 240 Torr and with a high absorbed power density of 500 W/cm3. To counter the issue of shrinking substrate size during growth, the effect of different substrate holder designs was studied. An increase in the substrate dimensions (1.23 -- 2.5 times) after growth was achieved when the sides of the seeds were shielded from the intense microwave electromagnetic fields in a pocket holder design. Using such pocket holders, high growth rates of 16 -- 32 mum/hr were obtained for growth times of 8 -- 72 hours. The polycrystalline diamond rim deposition was minimized/eliminated from these growth runs, hence successfully enlarging the substrate size. Several synthesized CVD SCD substrates were laser cut and separated

  9. Polarity-based separation and chemical characterization of fast pyrolysis bio-oil from poultry litter

    International Nuclear Information System (INIS)

    140 g Poultry litter pyrolysis oils (PL oils) were separated into four fractions using polarity based fractionation method. Four solvents of increasing polarity (hexane < toluene < chloroform < methanol) were used to sequentially fractionate the PL oil into four fractions (hexane fraction, toluene fraction, chloroform fraction and methanol fraction). The mass of hexane, toluene, chloroform and methanol fractions was 46 g, 29 g, 48 g and 14 g, respectively. The hexane and toluene fractions had low viscosity, while chloroform fraction was viscous and methanol fraction was almost solid at ambient laboratory conditions. The four PL oil fractions were characterized using Fourier Transform Infrared (FT-IR) spectrometry, 13C Nuclear Magnetic Resonance (NMR) spectrometry, and their organic elemental composition and higher heating values were also determined. Furthermore, major compounds in the four fractions were isolated by column chromatography. As a result, four compound classes (fatty acids, sterols, phenols and carbohydrates) and eleven major compounds were isolated from these four fractions. Oleic acid was predominant component of the hexane fraction (48.6%). The major component in methanol fraction was 1, 6-anhydro-β-D-glucose (16.7%), but the chloroform fraction had no predominant component. The 1, 6-anhydro-β-D-glucose and other sugar derivatives were water soluble and were selectively removed from the PL oil by water extraction and this subsequently decreased the viscosity of residual PL oil. - Highlights: • PL oil was separated into four fractions using polarity-based fractionation method. • The methanol fraction is a major cause of the high viscosity of the PL oil. • Fatty acids were predominant components of the hexane and toluene fractions. • The major component in methanol fraction was 1, 6-anhydro-glucose

  10. Quantifying components of the hydrologic cycle in Virginia using chemical hydrograph separation and multiple regression analysis

    Science.gov (United States)

    Sanford, Ward E.; Nelms, David L.; Pope, Jason P.; Selnick, David L.

    2012-01-01

    This study by the U.S. Geological Survey, prepared in cooperation with the Virginia Department of Environmental Quality, quantifies the components of the hydrologic cycle across the Commonwealth of Virginia. Long-term, mean fluxes were calculated for precipitation, surface runoff, infiltration, total evapotranspiration (ET), riparian ET, recharge, base flow (or groundwater discharge) and net total outflow. Fluxes of these components were first estimated on a number of real-time-gaged watersheds across Virginia. Specific conductance was used to distinguish and separate surface runoff from base flow. Specific-conductance data were collected every 15 minutes at 75 real-time gages for approximately 18 months between March 2007 and August 2008. Precipitation was estimated for 1971–2000 using PRISM climate data. Precipitation and temperature from the PRISM data were used to develop a regression-based relation to estimate total ET. The proportion of watershed precipitation that becomes surface runoff was related to physiographic province and rock type in a runoff regression equation. Component flux estimates from the watersheds were transferred to flux estimates for counties and independent cities using the ET and runoff regression equations. Only 48 of the 75 watersheds yielded sufficient data, and data from these 48 were used in the final runoff regression equation. The base-flow proportion for the 48 watersheds averaged 72 percent using specific conductance, a value that was substantially higher than the 61 percent average calculated using a graphical-separation technique (the USGS program PART). Final results for the study are presented as component flux estimates for all counties and independent cities in Virginia.

  11. Thin-Film Deposition of Metal Oxides by Aerosol-Assisted Chemical Vapour Deposition: Evaluation of Film Crystallinity

    Science.gov (United States)

    Takeuchi, Masahiro; Maki, Kunisuke

    2007-12-01

    Sn-doped In2O3 (ITO) thin films are deposited on glass substrates using 0.2 M aqueous and methanol solutions of InCl3(4H2O) with 5 mol % SnCl2(2H2O) by aerosol-assisted chemical vapour deposition under positive and negative temperature gradient conditions. The film crystallinity is evaluated by determining the film thickness dependence of X-ray diffraction peak height. When using aqueous solution, the ITO films grow with the same crystallinity during the deposition, but when using methanol solution, the preferred orientation of ITO changes during the deposition.

  12. Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)-nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

  13. Integration of plasma-assisted surface chemical modification, soft lithography, and protein surface activation for single-cell patterning

    Science.gov (United States)

    Cheng, Q.; Komvopoulos, K.

    2010-07-01

    Surface patterning for single-cell culture was accomplished by combining plasma-assisted surface chemical modification, soft lithography, and protein-induced surface activation. Hydrophilic patterns were produced on Parylene C films deposited on glass substrates by oxygen plasma treatment through the windows of polydimethylsiloxane shadow masks. After incubation first with Pluronic F108 solution and then serum medium overnight, surface seeding with mesenchymal stem cells in serum medium resulted in single-cell patterning. The present method provides a means of surface patterning with direct implications in single-cell culture.

  14. The production of chemicals from food processing wastes using a novel fermenter separator. Annual progress report, January 1993--March 1994

    Energy Technology Data Exchange (ETDEWEB)

    Dale, M.C.; Venkatesh, K.V.; Choi, H.; Salicetti-Piazza, L.; Borgos-Rubio, N.; Okos, M.R.; Wankat, P.C.

    1994-03-15

    The basic objective of this project is to convert waste streams from the food processing industry to usable fuels and chemicals using novel bioreactors. These bioreactors should allow economical utilization of waste (whey, waste sugars, waste starch, bottling wastes, candy wastes, molasses, and cellulosic wastes) by the production of ethanol, acetone/butanol, organic acids (acetic, lactic, and gluconic), yeast diacetyl flavor, and antifungal compounds. Continuous processes incorporating various processing improvements such as simultaneous product separation and immobilized cells are being developed to allow commercial scale utilization of waste stream. The production of ethanol by a continuous reactor-separator is the process closest to commercialization with a 7,500 liter pilot plant presently sited at an Iowa site to convert whey lactose to ethanol. Accomplishments during 1993 include installation and start-up of a 7,500 liter ICRS for ethanol production at an industry site in Iowa; Donation and installation of a 200 liter yeast pilot Plant to the project from Kenyon Enterprises; Modeling and testing of a low energy system for recovery of ethanol from vapor is using a solvent absorption/extractive distillation system; Simultaneous saccharification/fermentation of raw corn grits and starch in a stirred reactor/separator; Testing of the ability of `koji` process to ferment raw corn grits in a `no-cook` process.

  15. Membrane-assisted vapor stripping: energy efficient hybrid distillation-vapor permeation process for alcohol-water separation

    Science.gov (United States)

    BACKGROUND: Energy efficient alternatives to distillation for alcohol recovery from dilute solution are needed to improve biofuel sustainability. A process integrating steam stripping with a vapor compression step and a vapor permeation membrane separation step is proposed. The...

  16. Production of chemically reactive radioactive ion beams through on-line separation

    International Nuclear Information System (INIS)

    The ISOL (isotope separation on line) allows the production of secondary radioactive ion beams through spallation or fragmentation or fission reactions that take place in a thick target bombarded by a high intensity primary beam. The challenge is to increase the intensity and purity of the radioactive beam. The optimization of the system target/source requires the right choice of material for the target by taking into account the stability of the material, its reactivity and the ionization method used. The target is an essential part of the system because radioactive elements are generated in it and are released more or less quickly. Tests have been made in order to select the best fitted material for the release of S, Se, Te, Ge and Sn. Materials tested as target filling are: ZrO2, Nb, Ti, V,TiO2, CeOx, ThO2, C, ZrC4 and VC). Other molecules such as: COSe, COS, SeS, COTe, GeS, SiS, SnS have been studied to ease the extraction of recoil nuclei (Se, S, Te, Ge and Sn) produced inside the target

  17. Carbon and oxygen isotope separation by plasma chemical reactions in carbon monoxide glow discharge

    International Nuclear Information System (INIS)

    The separation of carbon and oxygen isotopes in CO glow discharge has been studied. The isotope enrichment in the products was measured by quadru-pole mass spectrometer. The reaction yield and empirical formula of solid phase products were determined by the gas-volumetric analysis. The stable products obtained in our experiment are CO2 and solid polymers formed on the discharge wall. The polymer consists of both carbon and oxygen and the oxygen/carbon mole ratio in the polymer is 0.35±0.05. Thi isotope enrichment coefficients show a strong negative dependence on discharge current though the relative reaction yields have an opposite tendency. Consequently, the maximum isotope enrichment coefficients for 13C in wall deposit of 2.31 and for 18O in CO2 of 1.37 are obtained when the discharge current and the reaction yields are minimum in our experimental range. The experimental results of isotope enrichment have been compared with theoretical values estimated by an analytical model of literature. The dilution mechanism of the isotope enrichment of stable products is inferred from the isotopic distributions of 13C and 18O in products and theoretical predictions for isotope enrichment. (author)

  18. Role of fluorine atoms in the oxidation-hydrolysis process of plasma assisted chemical vapor deposition fluorinated silicon nitride film

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, O.; Gomez-Aleixandre, C.; Palacio, C. (Universidad Autonoma de Madrid (Spain))

    The oxidation and/or hydrolysis of a plasma assisted chemical vapor deposition fluorinated silicon nitride film in a moisture atmosphere has been studied. The film presents fluorine atoms incorporated as -SiF, -SiF[sub 2], -SiF[sub 3], and [-SiF[sub 2]-][sub n] groups. The open structure of the film, due to the high fluorine content as [-SiF[sub 2]-][sub n], favors the penetration of oxygen and water molecules in the network. The evolution of the film has been explained by the different reactivity of the silicon atoms depending on their chemical environment. The role of fluorine atoms incorporated into the film has been established. 12 refs., 3 figs., 1 tab.

  19. The production of fuels and chemicals from food processing wastes using a novel fermenter separator

    Energy Technology Data Exchange (ETDEWEB)

    Dale, M.C.; Venkatesh, K.V.; Choi, Hojoon; Moelhman, M.; Saliceti, L.; Okos, M.R.; Wankat, P.C.

    1991-12-01

    During 1991, considerable progress was made on the waste utilization project. Two small Wisconsin companies have expressed an interest in promoting and developing the ICRS technology. Pilot plant sites at (1) Hopkinton, IA, for a sweet whey plant, and Beaver Dam WI, for an acid whey site have been under development siting ICRS operations. The Hopkinton, IA site is owned and operated by Permeate Refining Inc., who have built a batch ethanol plant across the street from Swiss Valley Farms cheddar cheese operations. Permeate from Swiss Valley is piped across to PRI. PRI has signed a contract to site a 300--500,000 gallon/yr to ICRS pilot plant. They feel that the lower labor, lower energy, continuous process offered by the ICRS will substantially improve their profitability. Catalytics, Inc, is involved with converting whey from a Kraft cream cheese operation to ethanol and yeast. A complete project including whey concentration, sterilization, and yeast growth has been designed for this site. Process design improvements with the ICRS focussed on ethanol recovery techniques during this year's project. A solvent absorption/extractive distillation (SAED) process has been developed which offers the capability of obtaining an anhydrous ethanol product from vapors off 3 to 9% ethanol solutions using very little energy for distillation. Work on products from waste streams was also performed. a. Diacetyl as a high value flavor compound was very successfully produced in a Stirred Tank Reactor w/Separation. b. Yeast production from secondary carbohydrates in the whey, lactic acid, and glycerol was studied. c. Lactic acid production from cellulose and lactose studies continued. d. Production of anti-fungal reagents by immobilized plant cells; Gossypol has antifungal properties and is produced by G. arboretum.

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

    OpenAIRE

    Fatih Kalkan; Sai Kranthi Vanga; Yvan Gariepy; Vijaya Raghavan

    2015-01-01

    In order to enhance the flavor, texture, color, and appearance of hazelnuts, they are roasted during postharvest processing. In this study, raw hazelnuts (Corylus avellana L.) were roasted using microwave (MW) and MW-assisted hot air methods under various roasting conditions. The hazelnuts roasted were then examined to determine the percent DPPH radical scavenging activity, antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, total starch, and protein concentr...

  1. chemical studies on the reactivity of some organic extractants for extraction and separation of certain elements from aqueous solutions

    International Nuclear Information System (INIS)

    Lanthanide elements such as lanthanum and neodymium are important elements in photo-electronic and metallurgical industries as well as in nuclear technology. The main constituents of the spent nuclear fuel are actinides like uranium, thorium and various fission products including lanthanides. The co-ordination compounds of the trivalent lanthanum and neodymium continues to be an active research area, which includes the specific spectroscopic and magnetic properties of rare earth ions and their applications as super molecular device, contrast-enhancing agents in magnetic resonance imaging, optical signal amplifiers and electroluminescent (EL) devices. Hence, the separation and purification of these elements is of great concern. Solvent extraction technique is employed to separate and purify rare earth elements in an industrial scale, but the separation of lanthanum and neodymium is a difficult task, as lanthanide ions exhibit similar chemical and physical properties. They have generally common and stable +3 oxidation state that requires synthesis of certain extractants which are able to extract them from different aqueous solutions. During the last twenty years, different publications have pointed out the remarkable properties of alkyl amide in the field of separation chemistry. These extractants are able to form stable co-ordination compounds with different metallic ions. In this concern, this thesis deals with the synthesis of different amide extractants namely N, N diethylacetoamide (DEAA), N, N Teteraphenyl malonamide (TPMA), N, N diphenylbenzamide (DPBA), N, N' diphenylacetoamide (DPAA), and N, N' Teteraethyl malonamide (TEMA), which were synthesized, characterized and compared with Aliquat-336 in kerosene for extraction and separation of La (III) and Nd (III). The effect of the different parameters affecting the extraction of these metals from aqueous nitric acid medium in the different systems has been studied in terms of shaking time, nitric acid, hydrogen

  2. A Microwave-Assisted Simultaneous Distillation and Extraction Method for the Separation of Polysaccharides and Essential Oil from the Leaves of Taxus chinensis Var. mairei

    OpenAIRE

    Chunjian Zhao; Xin He; Chunying Li; Lei Yang; Yujie Fu; Kaiting Wang; Yukun Zhang; Yujiao Ni

    2016-01-01

    An efficient microwave-assisted simultaneous distillation and extraction (MA-SDE) method has been developed for the separation of polysaccharides and essential oil from Taxus chinensis var. mairei. The key operating parameters for MA-SDE were optimized by single factor and central composite design experiments, and the optimal conditions were found to include a particle size of 60–80 mesh, liquid/solid ratio of 22.5 mL/g, extraction time of 17.5 min, microwave power of 547 W, and dichlorometha...

  3. Surfactant assisted chemical vapour generation of silver for AAS and ICP-OES: a mechanistic study

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Tomáš; Sturgeon, R. E.

    2003-01-01

    Roč. 18, č. 5 (2003), s. 487-494. ISSN 0267-9477 Institutional research plan: CEZ:AV0Z4031919 Keywords : vapour generation * ICP-OES * silver Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.200, year: 2003

  4. Development of New Generation of Ceramics for Environmentally Focused Chemical Separations

    Science.gov (United States)

    Ramakrishnan, Girish

    This dissertation focuses on the use of composite materials for environmental applications. For the first time, applications of both fresh and aged concrete as inexpensive adsorbents for nitrogen dioxide (NO2) removal is demonstrated. Concrete is the most widely used composite material of the modern era. Cement manufacturing (a major component of concrete) is considered to be one of the leading contributors to air pollution, resulting in 7% of the global carbon dioxide emissions along with a number of other harmful pollutants such as oxides, mercury and particulates. These emissions aide in the formation of acid rain, smog, and toxic ground level ozone, causing detrimental effects such as respiratory illnesses, visibility reduction, eutrification and global warming. This thesis offers a novel and sustainable solution in mitigating NOX emissions, by introducing the significant adsorption potential of recycled concrete. The work is based on both commercially available cement paste and already aged concrete samples, providing truly scalable solutions. The concrete samples aged for different periods of time were exposed to NO2 to measure their adsorption capacity. The results show that all of the concrete samples (fresh and aged) exhibited excellent NO2 adsorption capacity, with the fresh concrete samples removing almost 100% of the NO2. Furthermore, to compare the effects of long term aging, 12 year-old recently demolished concrete samples were obtained and its NOX removal was shown to be almost 60%. The experimental results provide evidence of nitrate and nitrite species formation from chemical reactions occurring between NO2 and surface alkaline species. This important discovery can be utilized for NO2 removal and subsequent NOX sequestered demolished concrete (NSDC) recycling in new concrete, either as a set accelerating admixture or as a corrosion inhibitor, a big leap towards better sustainability and longevity of the new reinforced concrete structures. The rest

  5. Equipment for leak monitoring of walls separating media in power and chemical installations, mainly nuclear power plants steam generators

    International Nuclear Information System (INIS)

    Equipment is described for leak monitoring of walls separating media in power and chemical installations. The partition walls consistf o two coaxial tubes. The inner surface of the outer tube and the outer surface of the inner tube are in contact. The contact surface is broken by at least one groove. Slots between both contact surfaces are connected to the intertube space into which one or more slots open. The configuration decreases or excludes the adverse effect of thermal resistance. In case of a medium penetrating in between the inner and the outer tubes, pressure in the slots, groove and intertube space changes. The change in the pressure value is recorded and is a measure of the average size of medium penetration. (J.B.)

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

    OpenAIRE

    Layana de Paula Cavalcante; Rita de Souza Tomás Falcão; Helder de Pádua Lima; Angélica Mota Marinho; Jaqueline Queiroz de Macedo; Violante Augusta Batista Braga

    2012-01-01

    The social support net is composed by the group of bonds related to the individual. Taking into account that the quality, as well as the quantity of these bonds can interfere in the person's life, acting as positive or negative element, it was identified the need to know this net of relationships by the professionals that takes care of such individuals. It was aimed to assess the Ecomap of drug users assisted in a specialized service as instrumental of support for health care. This is a quali...

  7. Quantitative evaluation of vertebral marrow adipose tissue in postmenopausal female using MRI chemical shift-based water–fat separation

    International Nuclear Information System (INIS)

    Aim: To investigate the feasibility of assessing vertebral marrow adipose tissue using a magnetic resonance imaging (MRI) chemical shift-based water–fat separation technique at 3 T. Material and methods: A modified Dixon technique was performed to obtain the vertebral marrow fat fraction (FF) in a study of 58 postmenopausal females (age range 49.2–77.4 years), including 24 normal bone density, 19 osteopaenia, and 15 osteoporosis as documented with dual-energy X-ray absorptiometry. The reliability of FF measurements performed by two radiologists independently was evaluated with the intraclass correlation coefficient (ICC). Ten participants were scanned twice to assess the reproducibility of FF measurements. FF values were compared between each vertebral level and between groups. Results: The mean coefficient of variation of FF measurements was 2.1%. According to the ICC, the measurements were reliable (ICC = 0.900 for normal bone density, ICC = 0.937 for osteopaenia and ICC = 0.909 for osteoporosis, p < 0.001 for all). There was an inverse association between mean FF at L1–L4 vertebrae and lumbar spine BMD (r = −0.459, p = 0.006), which remained significant even after controlling for confounders (age, height, and body weight). FF values at different vertebral levels were significantly correlated to each other (r = 0.703–0.921, p < 0.05 for all). There was a general trend toward increased marrow adiposity for more inferior vertebral bodies. Patients with osteopaenia and osteoporosis had a higher marrow fat content compared with normal bone mass after adjusting for confounders, although no significant differences in each vertebral level and average marrow fat content were found between the osteopaenia and osteoporosis groups. Conclusion: Chemical shift-based water–fat separation enables the quantitation of vertebral marrow adiposity with excellent reproducibility, which appears to be a useful method to provide complementary information to osteoporosis

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

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

  9. Use of assisted reproductive technology to separate sperm from human immunodeficiency virus infected men resulting in pregnancy among serodiscordant couples

    Directory of Open Access Journals (Sweden)

    Alessandro Schuffner

    2011-08-01

    Full Text Available Due to HIV care improvement, discordant couples more frequently seek help in order to conceive their own biological child. Besides the advance of antiretroviral therapy, unprotected intercourse is not a complete safe option, carrying a low but still present risk of HIV transmission. We report 10 serodiscordant couples in whom the male partner is HIV positive, submitted to sperm washing and intrauterine insemination. The procedure resulted in four pregnancies and no HIV transmission to mother or child was observed. Techniques of assisted reproduction can help HIV discordant couples to conceive biological offspring and is a safer option than unprotected intercourse.

  10. Visco chop-a new technique for nucleus separation for soft cataracts in femtolaser assisted cataract surgery

    Institute of Scientific and Technical Information of China (English)

    Sri; Ganesh; Sheetal; Brar

    2015-01-01

    <正>INTRODUCTION Femtosecond laser technology,introduced clinically for ophthalmic surgery as a technique for creating lamellar flaps in laser in situ keratomileusis(LASIK),has recently been developed into a tool for cataract surgery.Preliminary experience for femtosecond laser-assisted cataract surgery show appropriate safety and efficacy,and possible advantage over conventional cataract surgery[1-4].The ability of the femtosecond laser to fragment the lens results in the need for less ultrasound energy to be expended inside the eye.Several studies indicate that less effective phacoemulsification time is needed to emulsify the lens

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

    Science.gov (United States)

    Kalkan, Fatih; Kranthi Vanga, Sai; Gariepy, Yvan; Raghavan, Vijaya

    2015-01-01

    In order to enhance the flavor, texture, color, and appearance of hazelnuts, they are roasted during postharvest processing. In this study, raw hazelnuts (Corylus avellana L.) were roasted using microwave (MW) and MW-assisted hot air methods under various roasting conditions. The hazelnuts roasted were then examined to determine the percent DPPH radical scavenging activity, antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, total starch, and protein concentration. The roasting experiments were done using a completely randomized factorial arrangement of two roasting types by three roasting times (9, 15, and 21 min) by three roasting temperatures (70, 90, and 110°C) using three replications within each experiment. These roasting methods were found to yield significant differences in antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, and protein concentration between MW and MW-assisted hot air roasting processes, while no difference was found in percent DPPH radical scavenging activity and total starch. The results obtained may be of great importance to the food research community and industrial hazelnut roasting technologies. PMID:26689314

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

    Directory of Open Access Journals (Sweden)

    Fatih Kalkan

    2015-12-01

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

  13. Microwave-assisted chemical oxidation of biological waste sludge: simultaneous micropollutant degradation and sludge solubilization.

    Science.gov (United States)

    Bilgin Oncu, Nalan; Akmehmet Balcioglu, Isil

    2013-10-01

    Microwave-assisted hydrogen peroxide (MW/H2O2) treatment and microwave-assisted persulfate (MW/S2O8(2-)) treatment of biological waste sludge were compared in terms of simultaneous antibiotic degradation and sludge solubilization. A 2(3) full factorial design was utilized to evaluate the influences of temperature, oxidant dose, and holding time on the efficiency of these processes. Although both MW/H2O2 and MW/S2O8(2-) yielded ≥97% antibiotic degradation with 1.2g H2O2 and 0.87 g S2O8(2-) per gram total solids, respectively, at 160 °C in 15 min, MW/S2O8(2-) was found to be more promising for efficient sludge treatment at a lower temperature and a lower oxidant dosage, as it allows more effective activation of persulfate to produce the SO4(-) radical. Relative to MW/H2O2, MW/S2O8(2-) gives 48% more overall metal solubilization, twofold higher improvement in dewaterability, and the oxidation of solubilized ammonia to nitrate in a shorter treatment period. PMID:23928124

  14. Adaptive finite element method assisted by stochastic simulation of chemical systems

    Czech Academy of Sciences Publication Activity Database

    Cotter, S.L.; Vejchodský, Tomáš; Erban, R.

    2013-01-01

    Roč. 35, č. 1 (2013), B107-B131. ISSN 1064-8275 R&D Projects: GA AV ČR(CZ) IAA100190803 Institutional support: RVO:67985840 Keywords : chemical Fokker-Planck * adaptive meshes * stochastic simulation algorithm Subject RIV: BA - General Mathematics Impact factor: 1.940, year: 2013 http://epubs.siam.org/doi/abs/10.1137/120877374

  15. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    Science.gov (United States)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m2 and 20-40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  16. Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching

    International Nuclear Information System (INIS)

    Highlights: • Porous silicon/TiO2 nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO2 nanocomposites were established. • Valence-band XPS maximums for PSi/TiO2 nanocomposites were found and analyzed. - Abstract: PSi/TiO2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO2 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 TiO2 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 TiO2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO2 nanocomposites electronic structure. Surface defects states of Ti3+ at PSi/TiO2 nanocomposites were identified by analyzing of XPS valence band spectra

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

    KAUST Repository

    Cotter, Simon L.

    2013-01-01

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

  18. Growth of large size diamond single crystals by plasma assisted chemical vapour deposition: Recent achievements and remaining challenges

    Science.gov (United States)

    Tallaire, Alexandre; Achard, Jocelyn; Silva, François; Brinza, Ovidiu; Gicquel, Alix

    2013-02-01

    Diamond is a material with outstanding properties making it particularly suited for high added-value applications such as optical windows, power electronics, radiation detection, quantum information, bio-sensing and many others. Tremendous progresses in its synthesis by microwave plasma assisted chemical vapour deposition have allowed obtaining single crystal optical-grade material with thicknesses of up to a few millimetres. However the requirements in terms of size, purity and crystalline quality are getting more and more difficult to achieve with respect to the forecasted applications, thus pushing the synthesis method to its scientific and technological limits. In this paper, after a short description of the operating principles of the growth technique, the challenges of increasing crystal dimensions both laterally and vertically, decreasing and controlling point and extended defects as well as modulating crystal conductivity by an efficient doping will be detailed before offering some insights into ways to overcome them.

  19. The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching.

    Science.gov (United States)

    Zhong, Hao; Guo, Anran; Guo, Guohui; Li, Wei; Jiang, Yadong

    2016-12-01

    We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm. Silicon nanocone arrays can be created using MCE treatment. These modified surfaces show higher light absorptance in the near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the variations in the absorption spectra of the nanostructured black silicon with different etching processes are obtained. The maximum light absorptance increases significantly up to 95 % in the wavelength range of 400 to 2500 nm. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has potential application in near-infrared photoelectronic detectors. PMID:27368764

  20. Monte Carlo simulation of the behaviour of electrons during electron-assisted chemical vapour deposition of diamond

    Institute of Scientific and Technical Information of China (English)

    董丽芳; 陈俊英; 董国义; 尚勇

    2002-01-01

    The behaviour of electrons during electron-assisted chemical vapour deposition of diamond is investigated using Monte Carlo simulation. The electron energy distribution and velocity distribution are obtained over a wide range of reduced field E/N (the ratio of the electric field to gas molecule density) from 100 to 2000 in units of 1Td=10-17Vcm2.Their effects on the diamond growth are also discussed. Themain results obtained are as follows. (1) The velocity profile is asymmetric for the component parallel to the field.Ihe velocity distribution has a peak shift in the field direction. Most electrons possess non-zero velocity parallel to the substrate. (2) The number of atomic H is a function of E/N. (3) High-quality diamond can be obtained under the condition of E/N from 50 to 800Td due to sufficient atomic H and electron bombardment.

  1. Aerosol assisted chemical vapour deposition of germanium thin films using organogermanium carboxylates as precursors and formation of germania films

    Indian Academy of Sciences (India)

    Alpa Y Shah; Amey Wadawale; Vijaykumar S Sagoria; Vimal K Jain; C A Betty; S Bhattacharya

    2012-06-01

    Diethyl germanium bis-picolinate, [Et2Ge(O2CC5H4N)2], and trimethyl germanium quinaldate, [Me3Ge(O2CC9H6N)], have been used as precursors for deposition of thin films of germanium by aerosol assisted chemical vapour deposition (AACVD). The thermogravimetric analysis revealed complete volatilization of complexes under nitrogen atmosphere. Germanium thin films were deposited on silicon wafers at 700°C employing AACVD method. These films on oxidation under an oxygen atmosphere at 600°C yield GeO2. Both Ge and GeO2 films were characterized by XRD, SEM and EDS measurements. Their electrical properties were assessed by current–voltage (–) characterization.

  2. Pulse Operation of Chemical Oxygen-Iodine Laser by Pulsed Gas Discharge with the Assistance of Spark Pre-ionization

    Institute of Scientific and Technical Information of China (English)

    LI Guo-Fu; YU Hai-Jun; DUO Li-Ping; JIN Yu-Qi; WANG Jian; SANG Feng-Ting; FANG Ben-Jie; WANG De-Zhen

    2009-01-01

    The continuous wavelength chemical oxygen-iodine laser can be turned into pulse operation mode in order to obtain high energy and high pulse power. We propose an approach to produce iodine atoms instantaneously by pulsed gas discharge with the assistance of spark pre-ionization to achieve the pulsed goal. The influence of spark pre-ionization on discharge homogeneity is discussed. Voltage-current characteristics are shown and discussed in existence of the pre-ionization capacitor and peaking capacitor. The spark pre-ionization and peaking capacitor are very helpful in obtaining a stable and homogeneous discharge. The lasing is achieved at the total pressure of 2.2-2.9 kPa and single pulse energy is up to 180m J, the corresponding specific output energy is 1.0 J/L.

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

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2008-01-01

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

  4. Reduced thermal budget processing of Y-Ba-Cu-O films by rapid isothermal processing assisted metalorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    Metalorganic chemical vapor deposition (MOCVD) has the potential of emerging as a viable technique to fabricate ribbons, tapes, coated wires, and the deposition of films of high-temperature superconductors, and related materials. As a reduced thermal budget processing technique, rapid isothermal processing (RIP) based on incoherent radiation as the source of energy can be usefully coupled to conventional MOCVD. In this paper we report on the deposition and characterization of high quality superconducting thin films of Y-Ba-Cu-O (YBCO) on yttrium stabilized zirconia substrates by RIP assisted MOCVD. Using O2 gas as the source of oxygen, YBCO films deposited initially at 600 degree C for 1 min and at 745 degree C for 25 min followed by deposition at 780 degree C for 45 s are primarily c-axis oriented and zero resistance is observed at 89--90 K. The zero magnetic field current density at 53 and 77 K are 1.2x106 and 3x105 A/cm2, respectively. By using a mixture of N2O and O2 as the oxygen source substrate temperature was further reduced in the deposition of YBCO films. The films deposited initially at 600 degree C for 1 min and than at 720 degree C for 30 min are c-axis oriented and with zero resistance being observed at 91 K. The zero magnetic field current densities at 53 and 77 K are 3.4x106 and 1.2x106 A/cm2, respectively. To the best of our knowledge this is the highest value of critical current density, Jc for films deposited by MOCVD at a substrate temperature as low as 720 degree C. It is envisioned that high energy photons from the incoherent light source and the use of a mixture of N2O and O2 as the oxygen source, assist chemical reactions and lower overall thermal budget for processing of these films

  5. Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

    Science.gov (United States)

    Khalil, A. A. I.

    2015-06-01

    Two Nd:YAG lasers working in pulsed modes are combined in the same direction (collinear arrangement) to focus on silicon (Si) crystals in reduced oxygen atmosphere (0.1 mbar) for double-pulse laser-induced breakdown spectroscopy (DP-LIBS) system. Silicon crystals of (100) and (111) orientations were investigated, and Si samples were measured either without prior treatment ("untreated") or after fabrication of nano-pores ("treated"). Nano-pores are produced by metal coating and by chemical etching. DP-LIBS spectra were compared for different Si samples (untreated, treated, (100) and (111) orientations), for double-pulse (DP) (with 266 nm pulse followed by 1064 nm pulse) excitation and for different delay times (times between the excitation laser pulse and the detection ICCD gate); treatment by chemical etching has been studied as well. The intensity of the atomic line Si I at 288.16 nm was enhanced by a factor of about three by using the DP-LIBS signals as compared to the single-pulse (SP) signal which could increase the sensitivity of the LIBS technique. This study proved that an optimized value of the etching time of Si during etching by chemical processes and short delay times are required. Plasma parameters [the electron temperature ( T e) and the electron number density ( N e)] were calculated from measured SP- and DP-LIBS spectra. The most important result of this study is the much higher DP-LIBS intensity observed on Si (100) as compared to Si (111) for measurements under the same experimental conditions. This study could provide important reference data for the design and optimization of DP-LIBS systems involved in plasma-facing components diagnostics.

  6. Mesoscale elucidation of laser-assisted chemical deposition of Sn nanostructured electrodes

    International Nuclear Information System (INIS)

    Nanostructured tin (Sn) is a promising high-capacity electrode for improved performance in lithium-ion batteries for electric vehicles. In this work, Sn nanoisland growth for nanostructured electrodes assisted by the pulse laser irradiation has been investigated based on a mesoscale modeling formalism. The influence of pertinent processing conditions, such as pulse duration, heating/cooling rates, and atom flux, on the Sn nanostructure formation is specifically considered. The interaction between the adsorbed atom and the substrate, represented by the adatom diffusion barrier, is carefully studied. It is found that the diffusion barrier predominantly affects the distribution of Sn atoms. For both α-Sn and β-Sn, the averaged coordination number is larger than 3 when the diffusion barrier equals to 0.15 eV. The averaged coordination number decreases as the diffusion barrier increases. The substrate temperature, which is determined by heating/cooling rates and pulse duration, can also affect the formation of Sn nanoislands. For α-Sn, when applied low heating/cooling rates, nanoislands cannot form if the diffusion barrier is larger than 0.35 eV

  7. Selective removal technology using chemical etching and excimer assistance in precision recycle of color filter

    Institute of Scientific and Technical Information of China (English)

    Pai shan PA

    2011-01-01

    Color filters are produced using semiconductor production techniques although problems with Iow yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical etching, or electrochemical machining on the fifth generation TFT LCDs. The selective removal of microstructure layers from the color filter surface of an optoelectronic flat panel display, as well as complete removal of the ITO thin-films, RGB layer, or resin black matrix (BM) layer from the substrate is possible. Individual defective film layers can be removed, or all films down to the Cr layer or bare glass can be completely eliminated. Experimental results demonstrate that defective ITO thin-films, RGB layers, or the resin BM layer can now be recycled with a great precision. When the ITO or RGB layer proves difficult to remove, excimer light can be used to help with removal. During this recycling process, the use of 225 nm excimer irradiation before chemical etching, or electrochemical machining, makes removal of stubborn film residues easy, effectively improving the quality of recycled color filters and reducing fabrication cost.

  8. An object-oriented systems engineering model design for integrating spent fuel treatment facility and chemical separation processes

    International Nuclear Information System (INIS)

    In 2003, the United States Department of Energy (US DOE) launched the Advanced Fuel Cycle Initiative (AFCI) to address nuclear issues facing the United States. Amongst the major issues as identified by the AFCI were energy and waste management concerns. The interested nuclear wastes, based on their origin and toxicity, are spent nuclear fuel (SNF) and transuranic (TRU) wastes. While SNF wastes are those discharged from a nuclear reactor after being used for at least one cycle or a reactor operation, the TRU wastes are those that contain alpha-bearing radionuclides with atomic numbers greater than uranium. U.S. DOE plans to store its SNF and high-level waste (HLW) in a deep geologic disposal repository located at Yucca Mountain, Nevada. The risks that arise from long-term waste disposal come from approximately 1% of the fuels composition (transuranic group and long-lived isotopes of I and Tc). If transuranic species can be removed from the spent fuel, the toxicity of the waste drops below that of natural U within a period of several hundred years. The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that carries out effective transmutation and advanced reactor research and development effort. Integrated System for Optimized PROcesses (ISOPRO) package, developed from a multi-year project, integrates a chemical separation module, Argonne Model for Universal Solvent Extraction (AMUSE), from the Argonne National Laboratories (ANL) and commercially available system process package, such as ASPEN-Plus. Current research results focus on demonstrating the integration of the chemical separation program and system process package under the ISOPRO interfaces. Microsoft Visual Basic (MS VB) and MS Access database system has been chosen to develop the ISOPRO package. The developed user interface can directly execute and exchange parameters between the ASPEN-plus and AMUSE packages. The

  9. Tuning the Electrical Properties of Graphene via Nitrogen Plasma-Assisted Chemical Modification.

    Science.gov (United States)

    Jung, Min Wook; Song, Wooseok; Jung, Dae Sung; Lee, Sun Sook; Park, Chong-Yun; An, Ki-Seok

    2016-03-01

    The control in electrical properties of graphene is essentially required in order to realize graphenebased nanoelectronics. In this study, N-doped graphene was successfully obtained via nitrogen plasma treatment. Graphene was synthesized on copper foil using thermal chemical vapor deposition. After N2 plasma treatment, the G-band of the graphene was blueshifted and the intensity ratio of 2D- to G-bands decreased with increasing the plasma power. Pyrrolic-N bonding configuration induced by N2 plasma treatment was studied by X-ray photoelectron spectroscopy. Remarkably, electrical characterization including Hall measurement and I-V characteristics of the N-doped graphene exhibit semiconducting behavior as well as the n-type doping effect. PMID:27455703

  10. Characterization of tribo-layers on self-lubricating plasma-assisted chemical-vapor-deposited TiN coatings

    International Nuclear Information System (INIS)

    Recently, several new solid lubricants and modern lubrication concepts have been developed to achieve lower friction and wear and thus longer lifetime in severe tribological applications. The aim of this study is to characterize tribo-layers formed during ball-on-disc testing on low-friction, Cl-containing TiN coatings deposited by plasma assisted chemical vapor deposition and to clarify their formation mechanism. Characterization of the transfer layers was done by optical microscopy, optical profilometry, Raman spectroscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy. Differential scanning calorimetry was used to provide information on the chlorine-influenced chemical reactions of the coatings in ambient air. Iron oxide layers of a thickness in the nm-range have been found on low-chlorine containing TiN coatings (3 at.% Cl) rutile layers were preferably formed, resulting in friction coefficients below 0.2. This self-lubrication mechanism can be explained by the in-situ formation of easy-shearable titanium oxides in the contact zone in the presence of humidity and oxygen

  11. Speciation of trace elements in biological samples by nuclear analytical and related techniques coupled with chemical and biochemical separation

    International Nuclear Information System (INIS)

    In the past, most analytical problems relating to biological systems were addressed by measuring the total concentrations of elements. Now there is increasing interest of the importance of their chemical forms, in which an element is present in biological systems, e.g., the oxidation state, the binding state with macromolecules, or even the molecular structure. The biological effects of chromium, which is classified as an essential nutrient, are dependent upon its oxidation. state. In general, trivalent chromium is biochemically active, whereas hexavalent chromium is considered to be toxic. Mercury is one of serious environmental persistent pollutants. However, organic forms of mercury are known to possess much higher toxicity than inorganic mercury. Therefore, information on speciation is critically required in order to better understanding of their bioavailability, metabolism, transformation, and toxicity in vivo. Recently, chemical speciation of selenium, mercury, copper, zinc, iron, and so on, has been investigated by INAA, ICP-MS, XRF, EXAFS and related techniques combined with chemical and biochemical separation (extraction, chromatography, gel electrophoresis, etc.). INAA, XRF, and ICP-MS have superior advantages in aspect of multielemental analysis with high accuracy and sensitivity, which render the possibility of analyzing various elements of interest simultaneously. These offline or online techniques have been flexibly applied to different biological matrixes, such as human hair, serum, urine, various tissues and organs in our researches. In addition, EXAFS provides structural information about the moiety of metal centers up to a distance of approximately 4-5 Anstrom. For instance, hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Imbalance of elements, such as Se, Zn, Fe, Cu, Cd, Ca, etc., has been found in the whole blood or serum of patients with HCC. We found that the profiles of Se, Cd, Fe, Zn and Cu-containing proteins

  12. Synthesis of CdS nanostructures using template-assisted ammonia-free chemical bath deposition

    Science.gov (United States)

    Preda, N.; Enculescu, M.; Gherendi, F.; Matei, E.; Toimil-Molares, M. E.; Enculescu, I.

    2012-09-01

    CdS micro- and nano-structures (micro/nanotubes and nanostructured films) were obtained by ammonia-free chemical bath deposition using polymer templates (ion track-etched polycarbonate membranes and poly(styrene-hydroxyethyl methacrylate) nanosphere arrays). The semiconductor structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), optical absorption, photoluminescence and electrical measurements. The diameters of CdS tubes are between 300 nm and few microns and the lengths are up to tens of micrometers. The SEM images prove that the CdS films are nanostructured due to the deposition on the polymer nanosphere arrays. For both CdS structures (tubes and films) the XRD patterns show a hexagonal phase. The optical studies reveal a band gap value of about 2.5-2.6 eV and a red luminescence at ˜1.77 eV. A higher increase of conductivity is observed for illuminating the CdS nanostructured film when compared to the simple semiconductor film. This is a consequence of the periodic patterning induced by the polymer nanosphere array.

  13. Synthesis and characterization of GaN nanowires by a catalyst assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wei Xiaofeng [College of Physics and Electronics, Shandong Normal University, Jinan, 250014 (China); Shi Feng, E-mail: sf751106@163.com [College of Physics and Electronics, Shandong Normal University, Jinan, 250014 (China)

    2011-09-15

    GaN nanowires have been fabricated on Si(1 1 1) substrates by chemical vapor deposition (CVD) method with NiCl{sub 2} as catalyst and their compositions, microstructures, morphologies and light emitting properties were characterized by X-ray diffraction (XRD), FT-IR spectrophotometer (FTIR), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), Raman spectroscopy and photoluminescence (PL). The results demonstrate that the nanowires are single-crystal GaN with hexagonal wurtzite structure and high crystalline quality, having the size of 20-50 nm in diameter and several tens of microns in length with some nano-droplets on their tips, which reveals that the growth mechanism of GaN nanowires agrees with vapor-liquid-solid (VLS) process. Five first-order Raman active phonon bands move to low shift and A{sub 1}(TO), E{sub 1}(TO), and E{sub 2} (high) bands are overlapped and broaden, which is caused by uncertainty in the phonon wave vector. Five non-first-order active Raman phonons also appear, which is caused by the small dimension and high surface disorder degree. A blue-shift of the band-gap emission occurs due to quantum confinement effect.

  14. Chemo-selective high yield microwave assisted reaction turns cellulose to green chemicals.

    Science.gov (United States)

    Hassanzadeh, Salman; Aminlashgari, Nina; Hakkarainen, Minna

    2014-11-01

    Exceptionally high cellulose liquefaction yields, up to 87% as calculated from the amount of solid residue, were obtained under mild conditions by utilizing the synergistic effect of microwave radiation and acid catalysis. The effect of processing conditions on degradation products was fingerprinted by rapid laser desorption ionization-mass spectrometry (LDI-MS) method. The reaction was chemo-tunable, enabling production of glucose (Glc) or levulinic acid (LeA) at significantly high selectivity and yields, the relative molar yields being up to 50 and 69%, respectively. A turning point from pure depolymerization to glucose to further degradation to levulinic acid and formic acid was observed at approximately 50% liquefaction or above 140 °C. This was accompanied by the formation of small amounts of solid spherical carbonized residues. The reaction was monitored by multiple analytical techniques. The high yields were connected to the ability of the process to break the strong secondary interactions in cellulose. The developed method has great potential for future production of green platform chemicals. PMID:25129766

  15. Rapid, facile microwave-assisted synthesis of xanthan gum grafted polyaniline for chemical sensor.

    Science.gov (United States)

    Pandey, Sadanand; Ramontja, James

    2016-08-01

    Grafting method, through microwave radiation procedure is extremely productive in terms of time consumption, cost effectiveness and environmental friendliness. In this study, conductive and thermally stable composite (mwXG-g-PANi) was synthesized by grafting of aniline (ANi) on to xanthan gum (XG) using catalytic weight of initiator, ammonium peroxydisulfate in the process of microwave irradiation in an aqueous medium. The synthesis of mwXG-g-PANi were confirm by FTIR, XRD, TGA, and SEM. The influence of altering the microwave power, exposure time of microwave, concentration of monomer and the amount of initiator of graft polymerization were studied over the grafting parameters, for example, grafting percentage (%G) and grafting efficiency (%E). The maximum %G and %E achieved was 172 and 74.13 respectively. The outcome demonstrates that the microwave irradiation strategy can increase the reaction rate by 72 times over the conventional method. Electrical conductivity of XG and mwXG-g-PANi composite film was performed. The fabricated grafted sample film were then examined for the chemical sensor. The mwXG-g-PANi, effectively integrated and handled, are NH3 sensitive and exhibit a rapid sensing in presence of NH3 vapor. Chemiresistive NH3 sensors with superior room temperature sensing performance were produced with sensor response of 905 at 1ppb and 90% recovery within few second. PMID:27118045

  16. A chip assisted immunomagnetic separation system for the efficient capture and in situ identification of circulating tumor cells.

    Science.gov (United States)

    Tang, Man; Wen, Cong-Ying; Wu, Ling-Ling; Hong, Shao-Li; Hu, Jiao; Xu, Chun-Miao; Pang, Dai-Wen; Zhang, Zhi-Ling

    2016-03-23

    The detection of circulating tumor cells (CTCs), a kind of "liquid biopsy", represents a potential alternative to noninvasive detection, characterization and monitoring of carcinoma. Many previous studies have shown that the number of CTCs has a significant relationship with the stage of cancer. However, CTC enrichment and detection remain notoriously difficult because they are extremely rare in the bloodstream. Herein, aided by a microfluidic device, an immunomagnetic separation system was applied to efficiently capture and in situ identify circulating tumor cells. Magnetic nanospheres (MNs) were modified with an anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody to fabricate immunomagnetic nanospheres (IMNs). IMNs were then loaded into the magnetic field controllable microfluidic chip to form uniform IMN patterns. The IMN patterns maintained good stability during the whole processes including enrichment, washing and identification. Apart from its simple manufacture process, the obtained microfluidic device was capable of capturing CTCs from the bloodstream with an efficiency higher than 94%. The captured cells could be directly visualized with an inverted fluorescence microscope in situ by immunocytochemistry (ICC) identification, which decreased cell loss effectively. Besides that, the CTCs could be recovered completely just by PBS washing after removal of the permanent magnets. It was observed that all the processes showed negligible influence on cell viability (viability up to 93%) and that the captured cells could be re-cultured for more than 5 passages after release without disassociating IMNs. In addition, the device was applied to clinical samples and almost all the samples from patients showed positive results, which suggests it could serve as a valuable tool for CTC enrichment and detection in the clinic. PMID:26928405

  17. A phase separation method for analyses of fluoroquinones in meats based on ultrasound-assisted salt-induced liquid-liquid microextraction and a new integrated device.

    Science.gov (United States)

    Wang, Huili; Gao, Ming; Xu, Youqu; Wang, Wenwei; Zheng, Lian; Dahlgren, Randy A; Wang, Xuedong

    2015-08-01

    Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted, salt-induced, liquid-liquid microextraction for determination of five fluoroquinones in meats by HPLC analysis. The novel integrated device consisted of three simple HDPE (high density polyethylene) parts that were used to separate the solvent from the aqueous solution prior to retrieving the extractant. The extraction parameters were optimized using the response surface method based on central composite design: 589μL of acetone solvent, pH2.1, 4.1min extraction time and 3.5g of Na2SO4. The limits of detection were 0.056-0.64 μgkg(-1) and recoveries were 87.2-110.6% for the five fluoroquinones in muscle tissue from fish, chicken, pork and beef. This method is easily constructed from inexpensive materials, extraction efficiency is high, and the approach is compatible with HPLC analysis. Thus, it has excellent prospects for sample pre-treatment and analysis of fluoroquinones in meat samples. PMID:25885797

  18. Integration of phase separation with ultrasound-assisted salt-induced liquid-liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography.

    Science.gov (United States)

    Wang, Huili; Gao, Ming; Wang, Mei; Zhang, Rongbo; Wang, Wenwei; Dahlgren, Randy A; Wang, Xuedong

    2015-03-15

    Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on central composite design. Optimal conditions consisted of 945μL acetone extraction solvent, pH 2.1, 4.1min stir time, 5.9g Na2SO4, and 4.0min centrifugation. Under optimized conditions, the limits of detection (at S/N=3) were 0.12-0.66μgL(-1), the linear range was 0.5-500μgL(-1) and recoveries were 92.6-110.9% for the five FQs extracted from plasma and urine. The proposed method has several advantages, such as easy construction from inexpensive materials, high extraction efficiency, short extraction time, and compatibility with HPLC analysis. Thus, this method shows excellent prospects for sample pretreatment and analysis of FQs in human body fluids. PMID:25660716

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

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

  20. Antioxidant Activity and Thermal Stability of Oleuropein and Related Phenolic Compounds of Olive Leaf Extract after Separation and Concentration by Salting-Out-Assisted Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Konstantinos Stamatopoulos

    2014-04-01

    Full Text Available A fast, clean, energy-saving, non-toxic method for the stabilization of the antioxidant activity and the improvement of the thermal stability of oleuropein and related phenolic compounds separated from olive leaf extract via salting-out-assisted cloud point extraction (CPE was developed using Tween 80. The process was based on the decrease of the solubility of polyphenols and the lowering of the cloud point temperature of Tween 80 due to the presence of elevated amounts of sulfates (salting-out and the separation from the bulk solution with centrifugation. The optimum conditions were chosen based on polyphenols recovery (%, phase volume ratio (Vs/Vw and concentration factor (Fc. The maximum recovery of polyphenols was in total 95.9%; Vs/Vw was 0.075 and Fc was 15 at the following conditions: pH 2.6, ambient temperature (25 °C, 4% Tween 80 (w/v, 35% Na2SO4 (w/v and a settling time of 5 min. The total recovery of oleuropein, hydroxytyrosol, luteolin-7-O-glucoside, verbascoside and apigenin-7-O-glucoside, at optimum conditions, was 99.8%, 93.0%, 87.6%, 99.3% and 100.0%, respectively. Polyphenolic compounds entrapped in the surfactant-rich phase (Vs showed higher thermal stability (activation energy (Ea 23.8 kJ/mol compared to non-entrapped ones (Ea 76.5 kJ/mol. The antioxidant activity of separated polyphenols remained unaffected as determined by the 1,1-diphenyl-2-picrylhydrazyl method.

  1. Mechanical and chemical cleaning of the tubes bundles of the moisture separator reheaters (GSS) of Nuclear power plants

    International Nuclear Information System (INIS)

    The cleaning operation concerns the 'GSS' system (GSS stands for moisture separator reheaters, MSR) which are classified as 'watch quality guarantee', not classified as safety facility and subjected to Pressure Equipment regulations. The follow-up of the operational GSS (steel carbon) of EDF nuclear power plants CP0 group reveals a clog rate due to a relevant magnetite deposits that could result in equipment damage, loss of availability and loss of plant productivity. The pressure drop between inlet and outlet of the heating steam is close to maximum design criterion. The service consisted in designing, developing, qualifying and carrying out a process which removes clog from the inside of GSS U-tubes bundle located in the vapor circuit and which respects the equipment integrity and ensures the process harmlessness. This cleaning has to enable the complete removal of deposits and oxides (magnetite) in order to recover a passage diameter and a surface finish equivalent to the origin, thus avoiding the replacement of the GSS and obtaining a considerable reduction of costs. To do so, LAINSA and SOLARCA designed, developed, qualified and operated on 14 GSS bundles, by carrying out the following operations: - Cartography of the GSS tubes bundles clogging state; - Pre-Mechanical cleaning to un-block the sealed tubes and release the inside tubes passing; - Isolation of the bundle and check of leaks of the system; - Chemical cleaning with the efficiency and harmlessness parameters follow-up: - Acid Phase by means of weak organic acids to eliminate all the deposits; - Passivation phase; - Final Rinsing respecting the customer criteria; - Drying; - Waste management and waste treatment. The implementation of this operation enables the elimination of the whole deposits (magnetite) and oxides located inside the GSS tube bundle and thus to recover a passage diameter inside the tubes, and a pressure drop close to a new system and therefore to enables the

  2. Microwave-Assisted Extraction, Chemical Structures, and Chain Conformation of Polysaccharides from a Novel Cordyceps Sinensis Fungus UM01.

    Science.gov (United States)

    Cheong, Kit-Leong; Wang, Lan-Ying; Wu, Ding-Tao; Hu, De-Jun; Zhao, Jing; Li, Shao-Ping

    2016-09-01

    Cordyceps sinensis is a well-known tonic food with broad medicinal properties. The aim of the present study was to investigate the optimization of microwave-assisted extraction (MAE) and characterize chemical structures and chain conformation of polysaccharides from a novel C. sinensis fungus UM01. Ion-exchange and gel filtration chromatography were used to purify the polysaccharides. The chemical structure of purified polysaccharide was determined through gas chromatography-mass spectrometry. Moreover, high performance size exclusion chromatography combined with refractive index detector and multiangle laser light scattering were conducted to analyze the molecular weight (Mw ) and chain conformation of purified polysaccharide. Based on the orthogonal design L9 , optimal MAE conditions could be obtained through 1300 W of microwave power, with a 5-min irradiation time at a solid to water ratio of 1:60, generating the highest extraction yield of 6.20%. Subsequently, the polysaccharide UM01-S1 was purified. The UM01-S1 is a glucan-type polysaccharide with a (1→4)-β-d-glucosyl backbone and branching points located at O-3 of Glcp with a terminal-d-Glcp. The Mw , radius of gyration (Rg ) and hydrodynamic radius (Rh ) of UM01-S1 were determined as 5.442 × 10(6)  Da, 21.8 and 20.2 nm, respectively. Using the polymer solution theory, the exponent (ν) value of the power law function was calculated as 0.38, and the shape factor (ρ = Rg /Rh ) was 1.079, indicating that UM01-S1 has a sphere-like conformation with a branched structure in an aqueous solution. These results provide fundamental information for the future application of polysaccharides from cultured C. sinensis in health and functional food area. PMID:27514485

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

    Directory of Open Access Journals (Sweden)

    Miteva Maria A

    2008-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-30

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

  5. A melamine-assisted chemical blowing synthesis of N-doped activated carbon sheets for supercapacitor application

    Science.gov (United States)

    Wang, Yiliang; Xuan, Huaqing; Lin, Gaoxin; Wang, Fan; Chen, Zhi; Dong, Xiaoping

    2016-07-01

    N-doped activated carbon sheets (NACS) have been successfully synthesized using glucose as carbon source via melamine-assisted chemical blowing and sequent KOH-activation method. The obtained carbon material possesses a sheet-like morphology with ultrathin thickness, hierarchical micro/mesoporous structure, high specific surface area (up to 1997.5 m2 g-1) and high pore volume (0.94 cm3 g-1). Besides, NACS material with a nitrogen content of 3.06 wt% presents a maximum specific capacitance of 312 F g-1 at a current density of 0.5 A g-1 in 6 M KOH aqueous electrolyte due to the cocontribution of double layer capacitance and pseudocapacitance. It also displays good rate performance (246 F g-1 at 30 A g-1) and cycle stability (∼91.3% retention after 4000 galvanostatic charge-discharge cycles). The assembled NACS-based symmetric capacitor exhibits a maximum energy density of 20.2 Wh kg-1 at a power density of 448 W kg-1 within a voltage range of 0-1.8 V in 0.5 M Na2SO4 aqueous electrolyte. Thus, the unique porous sheet structure and nitrogen-doping characteristic endue the electrode material a potential application for high-performance supercapacitors.

  6. Plasma-assisted partial oxidation of methane at low temperatures: numerical analysis of gas-phase chemical mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Goujard, Valentin; Nozaki, Tomohiro; Yuzawa, Shuhei; Okazaki, Ken [Department of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, 1528552, Tokyo (Japan); Agiral, Anil, E-mail: tnozaki@mech.titech.ac.jp [Mesoscale Chemical Systems, MESA Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE, Enschede (Netherlands)

    2011-07-13

    Methane partial oxidation was investigated using a plasma microreactor. The experiments were performed at 5 and 300 deg. C. Microreactor configuration allows an efficient evacuation of the heat generated by methane partial oxidation and dielectric barrier discharges, allowing at the same time a better temperature control. At 5 deg. C, liquid condensation of low vapour pressure compounds, such as formaldehyde and methanol, occurs. {sup 1}H-NMR analysis allowed us to demonstrate significant CH{sub 3}OOH formation during plasma-assisted partial oxidation of methane. Conversion and product selectivity were discussed for both temperatures. In the second part of this work, a numerical simulation was performed and a gas-phase chemical mechanism was proposed and discussed. From the comparison between the experimental results and the simulation it was found that CH{sub 3}OO{center_dot} formation has a determinant role in oxygenated compound production, since its fast formation disfavoured radical recombination. At 5 deg. C the oxidation leads mainly towards oxygenated compound formation, and plasma dissociation was the major phenomenon responsible for CH{sub 4} conversion. At 300 deg. C, higher CH{sub 4} conversion resulted from oxidative reactions induced by {center_dot}OH radicals with a chemistry predominantly oxidative, producing CO, H{sub 2}, CO{sub 2} and H{sub 2}O.

  7. Growth mechanism of planar or nanorod structured tungsten oxide thin films deposited via aerosol assisted chemical vapour deposition (AACVD)

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Min; Blackman, Chris [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

    2015-07-15

    Aerosol assisted chemical vapour deposition (AACVD) is used to deposit tungsten oxide thin films from tungsten hexacarbonyl (W(CO){sub 6}) at 339 to 358 C on quartz substrate. The morphologies of as-deposited thin films, which are comprised of two phases (W{sub 25}O{sub 73} and W{sub 17}O{sub 47}), vary from planar to nanorod (NR) structures as the distance from the inlet towards the outlet of the reactor is traversed. This is related to variation of the actual temperature on the substrate surface (ΔT = 19 C), which result in a change in growth mode due to competition between growth rate (perpendicular to substrate) and nucleation rate (parallel to substrate). When the ratio of perpendicular growth rate to growth rate contributed by nucleation is higher than 7.1, the as-deposited tungsten oxide thin film forms as NR. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Pulsed Chemical Oxygen Iodine Lasers Excited by Pulse Gas Discharge with the Assistance of Surface Sliding Discharge Pre-ionization

    International Nuclear Information System (INIS)

    Continuous-wave chemical oxygen-iodine lasers (COILs) can be operated in a pulsed operation mode to obtain a higher peak power. The key point is to obtain a uniform and stable glow discharge in the mixture of singlet delta oxygen and iodide. We propose using an electrode system with the assistance of surface sliding pre-ionization to solve the problem of the stable glow discharge with a large aperture. The pre-ionization unit is symmetrically fixed on the plane of the cathode surface. A uniform and stable glow discharge is obtained in a mixture of iodide (such as CH3I) and nitrogen at the specific deposition energy of 4.5 J/L, pressure of 1.99–3.32 kPa, aperture size of 11 cm × 10 cm. The electrode system is applied in a pulsed COIL. Laser energy up to 4.4 J is obtained and the specific energy output is 2 J/L. (fundamental areas of phenomenology(including applications))

  9. Fabrication of silicon nanowire arrays by near-field laser ablation and metal-assisted chemical etching

    Science.gov (United States)

    Brodoceanu, D.; Alhmoud, H. Z.; Elnathan, R.; Delalat, B.; Voelcker, N. H.; Kraus, T.

    2016-02-01

    We present an elegant route for the fabrication of ordered arrays of vertically-aligned silicon nanowires with tunable geometry at controlled locations on a silicon wafer. A monolayer of transparent microspheres convectively assembled onto a gold-coated silicon wafer acts as a microlens array. Irradiation with a single nanosecond laser pulse removes the gold beneath each focusing microsphere, leaving behind a hexagonal pattern of holes in the gold layer. Owing to the near-field effects, the diameter of the holes can be at least five times smaller than the laser wavelength. The patterned gold layer is used as catalyst in a metal-assisted chemical etching to produce an array of vertically-aligned silicon nanowires. This approach combines the advantages of direct laser writing with the benefits of parallel laser processing, yielding nanowire arrays with controlled geometry at predefined locations on the silicon surface. The fabricated VA-SiNW arrays can effectively transfect human cells with a plasmid encoding for green fluorescent protein.

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

    International Nuclear Information System (INIS)

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

  11. CHEMICAL CHARACTERIZATION OF PULP COMPONENTS IN UNBLEACHED SOFTWOOD KRAFT FIBERS RECYCLED WITH THE ASSISTANCE OF A LACCASE/HBT SYSTEM

    Directory of Open Access Journals (Sweden)

    Luiz Pereira Ramos

    2007-11-01

    Full Text Available Oxidative treatments, without and with assistance of a Laccase-Mediator System (LMS, were characterized in relation to their effects on the chemical composition and strength properties of the fibrous fraction of an unbleached recycled softwood kraft pulp. The LMS, composed of a Trametes hirsuta laccase extract and 1-hydroxybenzotriazole (HBT, was applied on the fibrous fraction of a recycled pulp at low consistency under continuous stirring and oxygen bubbling. Control treatments adding neither the enzyme nor the mediator were also considered. The LMS treatment caused a partial reversion of the detrimental effects of hornification. A considerable increase in the amount of carbonyl groups on the lignin structure was observed as a result of the enzyme treatment. The amount of extractives in ethanol:toluene also increased after the enzymatic treatment, and the dioxane-soluble kraft lignin underwent a noticeable decrease in its apparent molecular mass. This latter effect was readily attributed to the hydrolysis of aryl-ether bonds that survived the severity employed in the pulping process. These observations were useful to explain why LMS-recycled fibers produce handsheets with 9.4% better tensile strength than the control pulps.

  12. Isotopic enrichment of diamond using microwave plasma-assisted chemical vapor deposition with high carbon conversion efficiency

    International Nuclear Information System (INIS)

    Isotopically-controlled diamond crystals were grown using microwave plasma-assisted chemical vapor deposition. First, the highest carbon isotopic enrichment and their controllability were examined. Although the highest 12C isotopic ratio of 99.998% was achieved using methane with an isotopic ratio of 99.999%, the memory effect of an unintended carbon isotope was found to be considerable when the carbon isotopic ratio of feeding methane was tuned for isotopic multilayer formation. Secondly, a unique gas feeding sequence was proposed for increasing the carbon conversion efficiency from methane to diamond. Increasing the conversion efficiency is done by finding a suitable balance between the methane feeding rate and the carbon consumption rate for diamond growth. A high conversion efficiency of 70% was obtained for a polycrystalline diamond with a high 12C isotopic ratio of 99.997%. - Highlights: • Isotopic control of diamond films was investigated. • A high microwave power density condition was applied for diamond growth. • The controllable range of the carbon isotopic ratio was demonstrated. • Diamond films having the highest 12C carbon isotopic enrichment were grown. • High carbon conversion efficiency of 70% was achieved

  13. Chemically modified polymeric resins for separation of cations, organic acids, and small polar moleculea by high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.B.

    1993-07-01

    This thesis is divided into 4 parts: a review, ion chromatography of metal cations on carboxylic resins, separation of hydrophilic organic acids and small polar compounds on macroporous resin columns, and use of eluent modifiers for liquid chromatographic separation of carboxylic acids using conductivity detection.

  14. Generation of diversiform gold nanostructures inspired by honey's components: growth mechanism, characterization, and shape separation by the centrifugation-assisted sedimentation.

    Science.gov (United States)

    Snitka, Valentinas; Naumenko, Denys O; Ramanauskaite, Lina; Kravchenko, Sergiy A; Snopok, Boris A

    2012-11-15

    The green synthesis of irregular-shaped nanomaterials used for various applications in nanoplasmonics, medicine, and biotechnology creates an economical and environmental challenge. We describe the rapid wet-chemical approach to synthesis of stable and water-soluble gold nanostructues at room temperature. In addition to spherical and road-like nanoparticles, gold decahedra and triangular plates were grown using the one-step synthesis process of HAuCl(4) in the presence of honey, in which main components act as reducing (glucose) and stabilizing (fructose) agents; the mechanism of the process is discussed in details. The requirements for anisotropic phase boundaries for generation of polyhedral gold nanocrystals in solutions are highlighted. The synthesis, morphology, and separation procedure of gold nanoparticles are examined using the techniques of optical spectroscopy, transmission electron microscopy, and atomic force microscopy. We demonstrate that centrifugation can be used for efficient separation of nanoparticles with different shapes from a mixture. It was found that while centrifuging, the spheres sediment at the bottom of the tube, segregating from rods that form a deposit on the side wall, whereas polygons remain in the solution. PMID:22918048

  15. Production of chemically reactive radioactive ion beams through on-line separation; Production de faisceaux d'ions radioactifs chimiquement reactifs par separation en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Joinet, A

    2003-10-01

    The ISOL (isotope separation on line) allows the production of secondary radioactive ion beams through spallation or fragmentation or fission reactions that take place in a thick target bombarded by a high intensity primary beam. The challenge is to increase the intensity and purity of the radioactive beam. The optimization of the system target/source requires the right choice of material for the target by taking into account the stability of the material, its reactivity and the ionization method used. The target is an essential part of the system because radioactive elements are generated in it and are released more or less quickly. Tests have been made in order to select the best fitted material for the release of S, Se, Te, Ge and Sn. Materials tested as target filling are: ZrO{sub 2}, Nb, Ti, V,TiO{sub 2}, CeO{sub x}, ThO{sub 2}, C, ZrC{sub 4} and VC). Other molecules such as: COSe, COS, SeS, COTe, GeS, SiS, SnS have been studied to ease the extraction of recoil nuclei (Se, S, Te, Ge and Sn) produced inside the target.

  16. Detection of bacteria from biological mixtures using immunomagnetic separation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    Science.gov (United States)

    Madonna, A.J.; Basile, F.; Furlong, E.; Voorhees, K.J.

    2001-01-01

    A rapid method for identifying specific bacteria from complex biological mixtures using immunomagnetic separation coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been developed. The technique employs commercially available magnetic beads coated with polycolonal antibodies raised against specific bacteria and whole cell analysis by MALDI-MS. A suspension of a bacterial mixture is mixed with the immunomagnetic beads specific for the target microorganism. After a short incubation period (20 mins) the bacteria captured by the beads are washed, resuspended in deionized H2O and directly applied onto a MALDI probe. Liquid suspensions containing bacterial mixtures can be screened within 1 h total analysis time. Positive tests result in the production of a fingerprint mass spectrum primarily consisting of protein biomarkers characteristic of the targeted microorganism. Using this procedure, Salmonella choleraesuis was isolated and detected from standard bacterial mixtures and spiked samples of river water, human urine, and chicken blood. Copyright ?? 2001 John Wiley & Sons, Ltd.

  17. The role of hydrogen in oxygen-assisted chemical vapor deposition growth of millimeter-sized graphene single crystals

    Science.gov (United States)

    Zhao, Pei; Cheng, Yu; Zhao, Dongchen; Yin, Kun; Zhang, Xuewei; Song, Meng; Yin, Shaoqian; Song, Yenan; Wang, Peng; Wang, Miao; Xia, Yang; Wang, Hongtao

    2016-03-01

    Involving oxygen in the traditional chemical vapor deposition (CVD) process has proven a promising approach to achieve large-scale graphene single crystals (GSCs), but its many relevant fundamental aspects are still not fully understood. Here we report a systematic study on the role of hydrogen in the growth of millimeter-sized GSCs using enclosure-like Cu structures via the oxygen-assisted CVD process. Results show that GSCs have different first layer growth behaviors on the inside and outside surfaces of a Cu enclosure when the H2 environment is varied, and these behaviors will consequently and strongly influence the adlayer formation in these GSCs, leading to two entirely different growth modes. Low H2 partial pressure (PH2) tends to result in fast growth of dendritically shaped GSCs with multiple small adlayers, but high PH2 can modify the GSC shape into hexagons with single large adlayer nuclei. This difference of adlayers is attributed to the different C diffusion paths determined by the shapes of their host GSCs. On the basis of these observations, we developed an isothermal two-step method to obtain GSCs with significantly improved growth rate and sample quality, in which low PH2 is first set to accelerate the growth rate followed by high PH2 to restrict the adlayer nuclei. Our results prove that the growth of GSCs can reach a reasonable optimization between their growth rates and sample quality by simply adjusting the CVD H2 environment, which we believe will lead to more improvements in graphene synthesis and fundamental insight into the related growth mechanisms.Involving oxygen in the traditional chemical vapor deposition (CVD) process has proven a promising approach to achieve large-scale graphene single crystals (GSCs), but its many relevant fundamental aspects are still not fully understood. Here we report a systematic study on the role of hydrogen in the growth of millimeter-sized GSCs using enclosure-like Cu structures via the oxygen-assisted CVD

  18. Dioxo-Fluoroalkoxide Tungsten(VI) Complexes for Growth of WOx Thin Films by Aerosol-Assisted Chemical Vapor Deposition.

    Science.gov (United States)

    Bonsu, Richard O; Kim, Hankook; O'Donohue, Christopher; Korotkov, Roman Y; Abboud, Khalil A; Anderson, Timothy J; McElwee-White, Lisa

    2015-08-01

    The soluble bis(fluoroalkoxide) dioxo tungsten(VI) complexes WO2(OR)2(DME) [1, R = C(CF3)2CH3; 2, R = C(CF3)3] have been synthesized by alkoxide-chloride metathesis and evaluated as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WOx. The (1)H NMR and (19)F NMR spectra of 1 and 2 are consistent with an equilibrium between the dimethoxyethane (DME) complexes 1 and 2 and the solvato complexes WO2(OR)2(CD3CN)2 [1b, R = C(CF3)2CH3; 2b, R = C(CF3)3] in acetonitrile-d3 solution. Studies of the fragmentation of 1 and 2 by mass spectrometry and thermolysis resulted in observation of DME and the corresponding alcohols, with hexafluoroisobutylene also generated from 1. DFT calculations on possible decomposition mechanisms for 1 located pathways for hydrogen abstraction by a terminal oxo to form hexafluoroisobutylene, followed by dimerization of the resulting terminal hydroxide complex and dissociation of the alcohol. AACVD using 1 occurred between 100 and 550 °C and produced both substoichiometric amorphous WOx and a polycrystalline W18O49 monoclinic phase, which exhibits 1-D preferred growth in the [010] direction. The work function (4.9-5.6 eV), mean optical transmittance (39.1-91.1%), conductivity (0.4-2.3 S/cm), and surface roughness (3.4-7.9 nm) of the WOx films are suitable for charge injection layers in organic electronics. PMID:26172992

  19. Physical and tribological properties of a-Si1-xCx:H coatings prepared by r.f. plama-assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    A-Si1-xCx:H films deposited by r.f. plasma-assisted chemical vapour deposition were studied as a function of their composition. The friction and wear properties were investigated with the help of a conventional ball-on-disc apparatus. These results are correlated with chemical (Si/C atomic ratio) and structural (Raman and infrared spectroscopy) properties. The friction coefficient in a humid ambient atmosphere changes markedly with the carbon fraction and reaches a value as low as 0.05 for coatings with 70 to 90 at.% C. The carbon-rich films consist of diamond-like carbon with silicon. (orig.)

  20. Characterization and modeling of 2D-glass micro-machining by spark-assisted chemical engraving (SACE) with constant velocity

    International Nuclear Information System (INIS)

    Spark-assisted chemical engraving (SACE) is an unconventional micro-machining technology based on electrochemical discharge used for micro-machining nonconductive materials. SACE 2D micro-machining with constant speed was used to machine micro-channels in glass. Parameters affecting the quality and geometry of the micro-channels machined by SACE technology with constant velocity were presented and the effect of each of the parameters was assessed. The effect of chemical etching on the geometry of micro-channels under different machining conditions has been studied, and a model is proposed for characterization of the micro-channels as a function of machining voltage and applied speed

  1. Fabrication and gas sensing properties of pure and au-functionalised W03 nanoneedle-like structures, synthesised via aerosol assisted chemical vapour deposition method

    OpenAIRE

    Stoycheva, Toni

    2011-01-01

    In this doctoral thesis, it has been investigated and developed the Aerosol Assisted Chemical Vapour Deposition (AACVD) method for direct in-situ growth of intrinsic and Au-functionalised nanostructured WO3, as well as SnO2-based devices for gas sensing applications. The nanostructured material synthesis, device fabrication and their gas sensing properties have been studied. AACVD method was used for synthesis and direct deposition of sensing films onto classical alumina and microhotplat...

  2. Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

    OpenAIRE

    Ouertani, Rachid; Hamdi, Abderrahmen; Amri, Chohdi; Khalifa, Marouan; Ezzaouia, Hatem

    2014-01-01

    In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to...

  3. Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol complex from environmental and biological samples.

    Science.gov (United States)

    Khan, Sumaira; Kazi, Tasneem Gul; Soylak, Mustafa

    2014-04-01

    A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid-liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40μgL(-1) and 100, respectively. The relative standard deviation (RSD) of 50μgL(-1) Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1-101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples. PMID

  4. 质谱图筛选红曲红色素纯化方法%MS Methods Assist Separation and Purification of A New Kind of Monasucs

    Institute of Scientific and Technical Information of China (English)

    刘立增; 孟宪昉; 白正晨; 王莉

    2015-01-01

    以商品化的红曲米为原料,利用质谱图定性分析,考察在红曲红色素提取过程中冷冻,索氏提取,溶剂,柱色谱,薄层色谱等因素对分离效果的影响,筛选并分离得到一种分子离子峰为332.6红曲红色素分子。研究结果表明该红曲红色素分子的纯化条件依次为:以甲醇为淋洗剂对红曲米进行柱色谱分离,以正己烷、乙酸乙酯和甲醇为萃取剂进行一次索氏提取,以CH2Cl2∶CH3OH=1∶1为展开剂进行薄层色谱分离,收集Rf=0.8的色带,以CH3CH2OH∶CCl4=9∶1为展开剂进行第二次薄层色谱分离,收集Rf=0.8的色带为目标分子,收率为0.0126%。%Commercial monascus red pigments were used as the raw material , the influence of the freezing temperature, Soxhlet extraction, solvents, column chromatography and thin layer chromatography separation process assisted by the use of mass methods were studied in details. A new kind of monasucs was screened out from the raw materials, the molecular ion peak located at 332.5. The experimental conditions for the purification of the monascus was:Before the Soxhlet extraction which hexane , ethyl acetate and methanol as the separated solvents, the red yeast rice subjected to column chromatography by the methanol used as the eluent. Then CH2Cl2∶CH3OH=1∶1 were used as the eluent for the thin layer chromatography ( Rf=0.8). Finally, a second thin layer chromatography were carried out to collect the the target molecule bond (Rf= 0.8) in which the CH3CH2OH∶CCl4=9∶1 were used as the corresponding eluents, yield 0.0126%.

  5. Ionic Liquid-Based Vacuum Microwave-Assisted Extraction Followed by Macroporous Resin Enrichment for the Separation of the Three Glycosides Salicin, Hyperin and Rutin from Populus Bark

    Directory of Open Access Journals (Sweden)

    Fengli Chen

    2014-07-01

    Full Text Available An effective ionic liquid vacuum microwave-assisted method was developed for extraction of the thermo- and oxygen-sensitive glycosides salicin, hyperin and rutin from Populus bark due to the strong solvating effects of ionic liquids on plant cell walls. In this study, [C4mim]BF4 solution was selected as the extracting solution for extraction of the target analytes. After optimization by single factor experiments and response surface methodology, the optimum condition parameters were achieved, which included 1.0 M [C4mim]BF4, 2 h soaking time, −0.08 MPa vacuum, 20 min microwave irradiation time, 400 W microwave irradiation power and 25 mL/g liquid/solid ratio. Under the optimum conditions, higher extraction yields of salicin (35.53 mg/g, hyperin (1.32 mg/g and rutin (2.40 mg/g were obtained. Compared with other extraction methods, the developed method provided higher yields of the three target components after a relatively shorter extraction time (20 min. No obvious degradation of the target analytes was observed under the optimum conditions in performed stability studies and the proposed method had a high reproducibility. Meanwhile, after adsorption and desorption on macroporous D101 resin, the target analytes can be effectively separated from the [C4mim]BF4 ionic liquid extraction solution and the yields of salicin, hyperin and rutin were 89%, 82% and 84%, respectively. The recovered [C4mim]BF4 ionic liquid presented a good extraction effect on the three analytes after recycling five times.

  6. Separating chemical and excluded volume interactions of polyethylene glycols with native proteins: Comparison with PEG effects on DNA helix formation.

    Science.gov (United States)

    Shkel, Irina A; Knowles, D B; Record, M Thomas

    2015-09-01

    Small and large PEGs greatly increase chemical potentials of globular proteins (μ2), thereby favoring precipitation, crystallization, and protein-protein interactions that reduce water-accessible protein surface and/or protein-PEG excluded volume. To determine individual contributions of PEG-protein chemical and excluded volume interactions to μ2 as functions of PEG molality m3 , we analyze published chemical potential increments μ23  = dμ2/dm3 quantifying unfavorable interactions of PEG (PEG200-PEG6000) with BSA and lysozyme. For both proteins, μ23 increases approximately linearly with the number of PEG residues (N3). A 1 molal increase in concentration of PEG -CH2 OCH2 - groups, for any chain-length PEG, increases μBSA by ∼2.7 kcal/mol and μlysozyme by ∼1.0 kcal/mol. These values are similar to predicted chemical interactions of PEG -CH2 OCH2 - groups with these protein components (BSA ∼3.3 kcal/mol, lysozyme ∼0.7 kcal/mol), dominated by unfavorable interactions with amide and carboxylate oxygens and counterions. While these chemical effects should be dominant for small PEGs, larger PEGS are expected to exhibit unfavorable excluded volume interactions and reduced chemical interactions because of shielding of PEG residues in PEG flexible coils. We deduce that these excluded volume and chemical shielding contributions largely compensate, explaining why the dependence of μ23 on N3 is similar for both small and large PEGs. PMID:25924886

  7. Electrochromic and colorimetric properties of nickel(II) oxide thin films prepared by aerosol-assisted chemical vapor deposition.

    Science.gov (United States)

    Sialvi, Muhammad Z; Mortimer, Roger J; Wilcox, Geoffrey D; Teridi, Asri Mat; Varley, Thomas S; Wijayantha, K G Upul; Kirk, Caroline A

    2013-06-26

    Aerosol-assisted chemical vapor deposition (AACVD) was used for the first time in the preparation of thin-film electrochromic nickel(II) oxide (NiO). The as-deposited films were cubic NiO, with an octahedral-like grain structure, and an optical band gap that decreased from 3.61 to 3.48 eV on increase in film thickness (in the range 500-1000 nm). On oxidative voltammetric cycling in aqueous KOH (0.1 mol dm(-3)) electrolyte, the morphology gradually changed to an open porous NiO structure. The electrochromic properties of the films were investigated as a function of film thickness, following 50, 100, and 500 conditioning oxidative voltammetric cycles in aqueous KOH (0.1 mol dm(-3)). Light modulation of the films increased with the number of conditioning cycles. The maximum coloration efficiency (CE) for the NiO (transmissive light green, the "bleached" state) to NiOOH (deep brown, the colored state) electrochromic process was found to be 56.3 cm(2) C(-1) (at 450 nm) for films prepared by AACVD for 15 min followed by 100 "bleached"-to-colored conditioning oxidative voltammetric cycles. Electrochromic response times were bleaching process. The films showed good stability when tested for up to 10 000 color/bleach cycles. Using the CIE (Commission Internationale de l'Eclairage) system of colorimetry the color stimuli of the electrochromic NiO films and the changes that take place on reversibly oxidatively switching to the NiOOH form were calculated from in situ visible spectra recorded under electrochemical control. Reversible changes in the hue and saturation occur on oxidation of the NiO (transmissive light green) form to the NiOOH (deep brown) form, as shown by the track of the CIE 1931 xy chromaticity coordinates. As the NiO film is oxidized, a sharp decrease in luminance was observed. CIELAB L*a*b* coordinates were also used to quantify the electrochromic color states. A combination of a low L* and positive a* and b* values quantified the perceived deep brown

  8. Analysis of copper (I) oxide thin films grown in a photo-assisted chemical vapor deposition reactor for photovoltaic applications

    Science.gov (United States)

    Mohiuddin, Omar H.

    Copper (I) oxide (Cu2O) has enormous potenetial for photovoltaic applications. Cu2O is a p-type semiconductor with a direct band gap of 2.2 eV. When grown on silicon, thin film Cu2O has the potential to increase photovoltaic eciency. Cu2O is a suitable photovoltaic material because it is inexpensive, non-toxic and abundant in the earth's crust. A model was developed based on a stagnation flow reactor with a reduction in activation energy for the precursor decomposition due to the light irradiation to model the light irradiation. The parameters that were tested were substrate temperature (200 to 700° C), gas temperature (100 and 150 °C) and carrier gas flow rate (25 to 100 sccm). The model was tested with a 480 nm and 172 nm light irradiation source and without any light irradiation source. This thesis utilizes a photo assisted chemical vapor deposition reactor to deposit films of Cu2O on silicon. The films were grown with a surface temperature of 700 °C, a gas temperature of 150 °C and an oxygen gas flow rate of 100 sccm. One deposition was done without the use of any light irradiation and another deposition was done with a 480 nm light irradiation source. X-ray diffraction, ellipsometry and transmission electron microscopy (TEM) were used to investigate the light irradiation eect on the lm growth and morphology. When grown with light irradiation, the ellipsometer showed that the film thickness increased to 98 +/- 6 nm from 74 +/- 10 nm, which shows that there is greater uniformity with a higher thickness when grown with light irradiation. The XRD results showed an increase in crystallinity in Cu2O grown with light irradiation, and the TEM results showed the grain sizes double when grown with light irradiation. The UV irradiation has been shown to increase the copper (I) oxide film quality and lm thickness. The model showed that the effect of the light irradiation was maximized at a surface temperature of 400 °C After this temperature the thermal eects become

  9. Ability of atmospheric pressure chemical ionization to detect of hydrocarbons separated by silver ion high performance liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Vrkoslav, Vladimír; Horká, Petra; Jindřich, J.; Cvačka, Josef

    Pardubice : University of Pardubice, 2013. P48-P48. ISBN 978-80-7395-648-6. [European Lipidomic Meeting /3./. 02.07.2013-04.07.2013, Pardubice] R&D Projects: GA ČR GAP206/12/1093 Institutional support: RVO:61388963 Keywords : HPLC * hydrocarbons * APCI Subject RIV: CB - Analytical Chemistry, Separation

  10. Optimized Chemical Separation and Measurement by TE TIMS Using Carburized Filaments for Uranium Isotope Ratio Measurements Applied to Plutonium Chronometry.

    Science.gov (United States)

    Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Prohaska, Thomas

    2016-06-21

    An optimized method is described for U/Pu separation and subsequent measurement of the amount contents of uranium isotopes by total evaporation (TE) TIMS with a double filament setup combined with filament carburization for age determination of plutonium samples. The use of carburized filaments improved the signal behavior for total evaporation TIMS measurements of uranium. Elevated uranium ion formation by passive heating during rhenium signal optimization at the start of the total evaporation measurement procedure was found to be a result from byproducts of the separation procedure deposited on the filament. This was avoided using carburized filaments. Hence, loss of sample before the actual TE data acquisition was prevented, and automated measurement sequences could be accomplished. Furthermore, separation of residual plutonium in the separated uranium fraction was achieved directly on the filament by use of the carburized filaments. Although the analytical approach was originally tailored to achieve reliable results only for the (238)Pu/(234)U, (239)Pu/(235)U, and (240)Pu/(236)U chronometers, the optimization of the procedure additionally allowed the use of the (242)Pu/(238)U isotope amount ratio as a highly sensitive indicator for residual uranium present in the sample, which is not of radiogenic origin. The sample preparation method described in this article has been successfully applied for the age determination of CRM NBS 947 and other sulfate and oxide plutonium samples. PMID:27240571

  11. Physico-Chemical Study of the Separation of Calcium Isotopes by Chemical Exchange Between Amalgam and Salt Solutions; Etude physico-chimique de la separation des isotopes du calcium par echange chimique entre amalgame et solution saline

    Energy Technology Data Exchange (ETDEWEB)

    Duie, P.; Dirian, G. [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    In a preliminary study of the isotopic exchange between Ca amalgam and aqueous or organic solutions of Ca salts, the main parameters governing the feasibility of a separation process based on these systems such as separation factor, exchange kinetics, rate of decomposition of the amalgam were investigated. The separation factor between {sup 40}Ca and {sup 46}Ca was found to be of the order of 1.02. The rate of the exchange reaction is rather low for aqueous solutions, extremely low for organic solutions. The amalgam seems not to be attacked by dimethyl-formamide solutions; but it is rapidly decomposed by aqueous solutions of Ca halides. This decomposition is slow in the case of aqueous solutions of calcium formate and still slower for Ca(OH){sub 2}; however, except in particular conditions, the observed rate is often much higher, owing to interfering reactions between amalgam and water vapor contained in H{sub 2} bubbles. (authors) [French] On a fait une etude preliminaire, pour des systemes amalgame de calcium - solution aqueuse ou organique de sels de calcium, des principaux parametres pouvant intervenir dans l'application d'un procede d'echange a l'enrichissement isotopique du calcium: facteur de separation, cinetique de l'echange, cinetique de la decomposition de l'amalgame. Les facteurs de separation {sup 40}Ca-{sup 46}Ca sont de l'ordre de 1,02. L'echange est assez lent pour les solutions aqueuses, extremement lent pour les solutions organiques. La decomposition de l'amalgame est pratiquement inexistante avec les solutions dans le dimethyl- formamide, appreciable pour les solutions alcooliques, rapide pour les solutions aqueuses d'halogenures; elle est normalement lente pour les solutions aqueuses de formiate et surtout de chaux, mais la decomposition est en general acceleree par une reaction parasite entre l'amalgame et l'eau a l'etat vapeur, reaction que l'on n'evite dans des

  12. 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

  13. Discrimination and chemical characterization of different Paeonia lactifloras (Radix Paeoniae Alba and Radix Paeoniae Rubra) by infrared macro-fingerprint analysis-through-separation

    Science.gov (United States)

    Wang, Yang; Wang, Ping; Xu, Changhua; Sun, Suqin; Zhou, Qun; Shi, Zhe; Li, Jin; Chen, Tao; Li, Zheng; Cui, Weili

    2015-11-01

    Paeonia lactiflora, a commonly used herbal medicine (HM) in Traditional Chinese Medicine (TCM), mainly has two species, Radix Paeoniae Alba (RPA) and Radix Paeoniae Rubra (RPR), for different clinical applications in TCM. For expounding the chemical profile of RPA and RPR and ensuring the clinical efficacy and safety, an infrared macro-fingerprint analysis-through-separation method integrated with statistical pattern recognition was developed to analyze and discriminate the two Paeonia lactifloras. In IR spectra, the major difference between the two was in the range of 1200-900 cm-1: the strongest peak of RPA was at 1024 cm-1, while that of RPR was 1049 cm-1. The difference was magnified in second derivative spectra. The findings were further verified by investigating the separation process of total glucosides, stepwisely monitored by both of IR and UPLC-MS/MS. Simultaneously, the aqueous extracts of RPA and RPR had been separated continuously to acquire the comprehensively hierarchical chemical characteristics for undoubtedly identification and subsequently discrimination of the two herbs. Moreover, 60 batches of the two HMs (30 for each) were objectively classified by principal component regression (PCR) model based on IR macro-fingerprints.

  14. In-line formation of chemically cross-linked P84® co-polyimide hollow fibre membranes for H2/CO2 separation

    KAUST Repository

    Choi, Seung Hak

    2010-12-13

    In this study, chemically cross-linked asymmetric P84® co-polyimide hollow fibre membranes with enhanced separation performance were fabricated, using a dry-wet spinning process with an innovative in-line cross-linking step. The chemical modification was conducted by controlled immersion of the coagulated fibre in an aqueous 1,5-diamino-2-methylpentane (DAMP) cross-linker solution before the take-up. The effect of the cross-linker concentration on the thermal, mechanical, chemical and gas transport properties of the membranes was investigated. FT-IR/ATR analysis was used to identify the chemical changes in the polymer, while DSC analysis confirmed the changes in the Tg and the specific heat of the polymer upon cross-linking. Chemical cross-linking with a 10 wt.% aqueous DAMP solution strongly enhanced the H2/CO2 ideal selectivity from 5.3 to 16.1, while the H2 permeance of the membranes decreased from 7.06 × 10−3 to 1.01 × 10−3 m3(STP) m−2 h−1 bar−1 for a feed pressure of 1 bar at 25 °C. The increase of selectivity with decreasing permeance is somewhat higher than the slope in the Robeson upper bound, evidencing the positive effect of the cross-linking on the separation performance of the fibres. Simultaneously, the cross-linking leads to improved mechanical resistance of the membranes, which could be further enhanced by an additional thermal treatment. The produced membranes are therefore more suitable for use under harsh conditions and have a better overall performance than the uncross-linked ones.

  15. Multi trace element analysis of dry biological materials by neutron activation analysis including a chemical group separation

    International Nuclear Information System (INIS)

    Multi-element analysis of dry biological material by neutron activation analysis has to include radiochemical separation. The evaporation process is described in terms of the half-volume. The pretreatment of the samples and the development of the destruction-evaporation apparatus are described. The successive adsorption steps with active charcoal, Al2O3 and coprecipitation with Fe(OH)3 are described. Results obtained for standard reference materials are summarized. (G.T.H.)

  16. Sonication-assisted sequential chemical bath deposition of CdS nanoparticles into TiO2 nanotube arrays for application in solar cells

    International Nuclear Information System (INIS)

    Highlights: ► CdS sensitized TNTAs photoanode were prepared by sonication-assisted CBD approach. ► Sonication-assisted CBD (SSCBD) prevents CdS aggregating at the top of TNTAs. ► SSCBD promote the deposition quantity of nanoparticles into the TNTAs effectively. ► Compared with classical CBD, S-CdS/TNTAs cells exhibit an increase of η by 65.8%. - Abstract: CdS nanoparticles sensitized TiO2 nanotube arrays photoanode for semiconductors sensitized solar cells (SSSCs) were prepared by sonication-assisted sequential chemical bath deposition (SSCBD) approach and labeled as S-CdS/TNTAs. The S-CdS/TNTAs solar cell was assembled into a typical sandwich structure with backside illumination. Short-circuit current density (Jsc), open circuit potential (Voc), fill factor (FF) and power conversion efficiency (PCE) of the cells under AM 1.5 irradiation were about 4.16 mA cm−2, 446 mV, 43.9% and 0.814%, respectively. Compared with classical sequential chemical bath deposition (SCBD), SSCBD process could effectively prevent CdS nanoparticles aggregating at the top surface of TNTAs and resulted in an increase of PCE by 65.8%. Increased performance of S-CdS/TNTAs solar cell may be attributed to the more efficient charge-transfer process and the lower charge recombination, as evidenced from FESEM and electrochemical impedance spectroscopy (EIS).

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

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

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

  18. Controlling Solution Self-assembly and Non-Solvent Induced Microphase Separation of Triblock Terpolymers to Generate Nanofiltration Membranes with Chemically-Tailored Pore Walls

    Science.gov (United States)

    Boudouris, Bryan; Mulvenna, Ryan; Weidman, Jacob; Phillip, William

    2014-03-01

    Block polymer-based templates have been utilized in a number of membrane applications; however, there has yet to be a demonstration of a nanoporous block polymer thin film that can achieve high flux and high selectivity simultaneously while also allowing for the facile tuning of the pore wall chemistry. Here, we demonstrate that by synthesizing and controlling the solution self-assembly of a triblock terpolymer, polyisoprene- b-polystyrene- b-poly(N, N-dimethylacrylamide) (PI-PS-PDMA), and precisely inducing non-solvent induced phase separation during the self-assembly process allows for the creation of an asymmetric nanoporous membrane with PDMA-lined pore walls. This PDMA functionality is then converted to any number of side chain functionalities through simple chemistry in the solid state. In this way, we are able to show a highly selectivity membrane that can separate analytes of interest based both on size and chemical composition at a high solution flux. In fact, this high fidelity structure has a very narrow distribution of pore sizes (500 cm2) . This has allowed for the separation of particles with hydrodynamic radii as low as 0.8 nm, which is the smallest separation achieved using a block polymer-based membrane to date.

  19. SHIP, the Separator for Heavy Ion Reaction Products, and the making of the heaviest atomic nuclei. Roentgenium - a new chemical element

    International Nuclear Information System (INIS)

    Ever since the foundation of the GSI, the Darmstadt-based Gesellschaft fuer Schwerionenforschung, in the 1970s, physicists of the Justus-Liebig-University of Giessen have been at the frontiers of research work examining the behaviour of nuclear matter under critical stability conditions. The article in this edition of ''Spiegel der Forschung'', the scientific journal of the university, highlights the results of the last twenty years of research activities with the velocity separator named SHIP, Separator for Heavy Ion Reaction Products. With this instrument, developed by members of the university's II. Institute of Physics and built and operated by members of the GSI in Darmstadt, the scientists were able to generate the six heaviest of the currently known chemical elements, with atomic numbers ranging from 107 to 112. The element with the atomic number 111 will be named ''Roentgenium'', in honour of the famous physicist and Nobel prize winner Wilhelm Conrad Roentgen

  20. Separation of boron isotopes at chemical isotopic exchange between, boron trifluoride and its complex with anisole in multitube mass-exchange column

    International Nuclear Information System (INIS)

    The results are given on continuous counterflow two-phase process of boron isotopes 10B and 11B separation at chemical isotopic exchange between gaseous BF3 and its liquid complex with anisole, the process is realized in the module of three packed columns with parallel operation; each of the columns in its bottom part is connected with the others by the common unit of flow reversal (desorber), has the diameter of 78 mm, height of 46.5 m, and is filled with wire spiral-prismatic pack with 3.5·3.5·0.2 mm element

  1. Volume reduction on all particle size of the contaminated soil. Continuous processing technology of attrition, chemical wash under an ambient temperature and pressure condition and magnetic separation

    International Nuclear Information System (INIS)

    An examination was conducted in order to establish a practical purification system that could largely reduce the storage volume of radioactive waste in the Intermediate Storage Facility. The examination consists of a 3-step washing treatment of contaminated soil, which includes “Milling Washing” of removed contaminated soil, chemical extraction of fine soil fraction resulted from the “Milling Washing” under an ambient temperature and pressure condition, and magnetic separation of cesium from the extracted solution. As a result of the examination, we succeeded in development of a safe system with low initial cost and running cost. (author)

  2. Improvement in the chemical separation and determination of uncertainties for bulk analysis of Pu isotopes at ultra-trace levels by using MC-ICP-MS

    International Nuclear Information System (INIS)

    Improved bulk analysis based on extraction chromatography and systematic evaluations of uncertainties of plutonium isotopes at ultra-trace levels in environmental swipe samples are presented. In the modified method based on a single column system using UTEVA resin for MC-ICP-MS, hydrogen peroxide was introduced to obtain pure plutonium isotopes from chemical separation by removing excess organic-based reducing reagents. We confirmed that hydrogen peroxide effectively decomposed the reducing reagents characterized by UV-Vis absorption spectroscopy and the peak fluctuations were significantly reduced. To examine the reliability of analytical performance, we systematically evaluated the combined uncertainties during the overall chemical procedures using simulated samples containing Pu reference materials. (author)

  3. Kawasaki Disease With Giant Coronary Aneurysms Requiring a Ventricular Assist Device to Separate From Extracorporeal Membrane Oxygenation: Coronary Issues Can Be a Pediatric Problem Too!

    Science.gov (United States)

    Adler, Adam C; Kodavatiganti, Ramesh

    2016-08-15

    Kawasaki disease, although common in children, may rarely affect the coronary arteries, leading to aneurysm formation and potential for coronary thrombus formation. Extremely rarely, coronary aneurysms from Kawasaki disease can thrombose, resulting in ischemic myocardium. We present a case of a 31-month-old patient requiring a left ventricular assist device after thrombosis of giant coronary aneurysms led to ischemic cardiomyopathy. At the termination of the surgical procedure, we encountered 2 periods of ventricular assist device dropout requiring intervention. With the increase in the number of pediatric patients with assist devices, we review the basic care for a patient requiring emergent surgery. PMID:27310902

  4. Investigations on the effects of plasma-assisted pre-treatment for plasma-assisted chemical vapour deposition TiN coatings on tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Gammer, K.; Stoiber, M.; Wagner, J.; Hutter, H.; Kullmer, R.; Mitterer, C

    2004-08-16

    Different mixtures of hydrogen, nitrogen and argon were tested for the cleaning and nitriding of cold-working, high chromium tool steel, prior to TiN deposition with the aim of improving adhesion of the TiN layer. It is well known that the condition of the substrate surface and hardening of the substrate by nitriding have a large influence on the adhesion strength of films. Good adhesion was achieved when nitrogen-hydrogen atmosphere with 40%-80% nitrogen (and 20%-60% hydrogen, respectively) was used, the best adhesion quality values were achieved (HF 1-2) with 40% nitrogen. With higher or lower fractions of nitrogen in the pre-treatment gas, adhesion was reduced. Argon addition also had negative effects on the adhesion strength. The microstructure and chemical composition of the near-interface region of the differently pretreated samples were analysed using secondary ion mass spectrometry, X-ray diffraction and light optical microscopy.

  5. Investigations on the effects of plasma-assisted pre-treatment for plasma-assisted chemical vapour deposition TiN coatings on tool steel

    International Nuclear Information System (INIS)

    Different mixtures of hydrogen, nitrogen and argon were tested for the cleaning and nitriding of cold-working, high chromium tool steel, prior to TiN deposition with the aim of improving adhesion of the TiN layer. It is well known that the condition of the substrate surface and hardening of the substrate by nitriding have a large influence on the adhesion strength of films. Good adhesion was achieved when nitrogen-hydrogen atmosphere with 40%-80% nitrogen (and 20%-60% hydrogen, respectively) was used, the best adhesion quality values were achieved (HF 1-2) with 40% nitrogen. With higher or lower fractions of nitrogen in the pre-treatment gas, adhesion was reduced. Argon addition also had negative effects on the adhesion strength. The microstructure and chemical composition of the near-interface region of the differently pretreated samples were analysed using secondary ion mass spectrometry, X-ray diffraction and light optical microscopy

  6. Measuring binding and speciation of hydrophobic organic chemicals at controlled freely dissolved concentrations and without phase separation

    DEFF Research Database (Denmark)

    Gouliarmou, Varvara; Smith, K E C; de Jonge, Lis Wollesen;

    2012-01-01

    (dimethylsiloxane) polymer preloaded with the chemicals. The HOC concentrations in the equilibrated solutions [Csolution(eq)] and water [Cwater(eq)] were then measured. Free fractions of the HOCs were determined as Cwater(eq)/Csolution(eq), whereas enhanced capacities (E) of the solutions for HOCs were determined as...... simple linear regression provided precise partition ratios, salting out constants, and critical micelle concentrations. These parameters were generally in good agreement with published values obtained by solid phase microextraction and fluorescence quenching. The very good precision was indicated by the...

  7. Chemical enrichment and separation of uranyl ions in aqueous media using novel polyurethane foam chemically grafted with different basic dyestuff sorbents.

    Science.gov (United States)

    El-Shahat, M F; Moawed, E A; Farag, A B

    2007-01-15

    The new type of the grafted polyurethane foam sorbents were prepared by coupling polyether polyol, toluene diisocyanate and basic dyestuff (Methylene blue, Rhodamine B and Brilliant green). The Me.B-PUF, Rh.B-PUF and Br.G-PUF were characterized using UV/vis, IR and TGA. The adsorption properties and chromatographic behaviour of these new adsorbents for preconcentration and separation of uranium(VI) ions at low concentrations from aqueous thiocyanate media were investigated by a batch process. The maximum sorption of U(VI) was in the pH ranges 1-4. The kinetics of sorption of the U(VI) by the Grafted-PUF were found to be fast with half life of sorption (t(1/2)) in 2.43min. The average sorption capacity of different sorbents 0.124meqg(-1) for uranyl ions, enrichment factors approximately 40 and the recovery 98-100% were achieved (R.S.D. approximately 0.73%). The basic dyestuff Grafted-PUF could be used many times without decreasing their capacities significantly. The value of the Gibbs free energy (DeltaG) for the sorbents is -7.3kJmol(-1), which reflects the spontaneous nature of sorption process. The sorption mechanism of the metal ion onto Grafted-PUF was also discussed. PMID:19071294

  8. Effect of surfactants on the morphology of FeSe films fabricated from a single source precursor by aerosol assisted chemical vapour deposition

    Indian Academy of Sciences (India)

    Raja Azadar Hussain; Amin Badshah; Naghma Haider; Malik Dilshad Khan; Bhajan Lal

    2015-03-01

    This article presents the fabrication of FeSe thin films from a single source precursor namely (1-(2-fluorobenzoyl)-3-(4-ferrocenyl-3-methylphenyl)selenourea (MeP2F)) by aerosol assisted chemical vapour deposition (AACVD). All the films were prepared via similar experimental conditions (temperature, flow rate, concentration, solvent system and reactor type) except the use of three different concentrations of two different surfactants i.e., triton and span. Seven thin films were characterized with PXRD, SEM, AFM, EDS and EDS mapping. The mechanism of the interaction of surfactant with MeP2F was determined with cyclic voltammetry (CV) and UV-Vis spectroscopy.

  9. The effect of thermal conductivity of the tool electrode in spark-assisted chemical engraving gravity-feed micro-drilling

    International Nuclear Information System (INIS)

    Spark-assisted chemical engraving (SACE) is a non-traditional micro-machining technology based on electrochemical discharge phenomena. In SACE gravity-feed micro-drilling, various parameters including the thermal properties of the tool electrode play a significant role in the process. Based on a series of experiments using tool electrodes with different thermal properties, the effect in SACE gravity-feed micro-drilling is discussed. It is demonstrated that machining with higher thermal conductivity tool electrodes results in faster machining during the discharge regime and slower machining during the hydrodynamic regime of SACE gravity-feed micro-drilling

  10. Hydrogen plasma enhanced alignment on CNT-STM tips grown by liquid catalyst-assisted microwave plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Carbon nanotubes are grown directly on a scanning tunneling microscopy tip by liquid catalyst-assisted microwave-enhanced chemical vapor deposition, and effects of hydrogen plasma treatment on the tip have been investigated in detail by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. The unaligned CNTs on the as-grown tip apex have been realigned and reshaped by subsequent hydrogen plasma treatment. The diameter of CNTs is enlarged mainly due to amorphous layers being re-sputtered over their outer shells

  11. High-Jc YBa2Cu3O7-δ superconducting film grown by laser-assisted chemical vapor deposition using a single liquid source and its microstructure

    Science.gov (United States)

    Zhao, Pei; Ito, Akihiko; Kato, Takeharu; Yokoe, Daisaku; Hirayama, Tsukasa; Goto, Takashi

    2013-09-01

    A YBa2Cu3O7-δ (YBCO) film was prepared on a multilayer-coated Hastelloy C276 substrate by laser-assisted metalorganic chemical vapor deposition using a single liquid source precursor. A c-axis-oriented YBCO film was grown epitaxially on a (100) CeO2 layer at a deposition rate of 11 μm h-1. A screw dislocation and stacking faults were observed in the cross-section of the YBCO film. The critical current density of the YBCO film reached 2.7 MA cm-2.

  12. Room temperature chemically oxidized La2CuO4+y: Phase separation induced by thermal treatment

    DEFF Research Database (Denmark)

    Rial,C.; Moran, E.; Alario-Franco, M.A.;

    1997-01-01

    The structure of roam temperature chemically oxidized La2CuO4+y [y = 0.103(4)] has been refined from powder neutron diffraction data using the space group Bmab. The modifications induced in the CuO2 and the LaO planes by the insertion of oxygen are consistent with the high T-c measured for this m......The structure of roam temperature chemically oxidized La2CuO4+y [y = 0.103(4)] has been refined from powder neutron diffraction data using the space group Bmab. The modifications induced in the CuO2 and the LaO planes by the insertion of oxygen are consistent with the high T-c measured...... for this material. The thermogravimetric analysis(TGA) of La2CuO4.103(4) evidences an unexplained two-step mass loss process. Based on this observation, three samples obtained by different thermal treatments of the fully oxidized material were studied by TGA, X-ray diffraction and AC magnetic susceptibility, After......, it seems likely that the plateau observed in the TGA curve of La2CuO4.103(4) might be due to the formation on heating of a stable phase with a fixed oxygen stoichiometry, i.e. La2CuO4.086(4). The stability of this phase could be related-to the presence of one-dimensional interstitial oxygen ordering along...

  13. Gas phase chemical studies of superheavy elements using the Dubna gas-filled recoil separator - Stopping range determination

    International Nuclear Information System (INIS)

    Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40-270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction 244Pu(48Ca; 3n)289114. One decay chain assigned to an atom of 285112, the α-decay product of 289114, was observed.

  14. Physico-Chemical Methods for the Separation and Estimation of Vitamin A in Fish Oils and other Pharmaceuticals

    Directory of Open Access Journals (Sweden)

    H. K. Kulshreshtha

    1965-11-01

    Full Text Available A review of the different physico-chemical procedures, including colorimetric methods employed in the determination of vitamin A in pharmaceuticals (with greater emphasis on the Carr-Price reaction, involving the antimony-trichloride and glycerol-dichlorohydrin reagentand the spectrophotometric technique, has been presented. Need for further work with regard to the determination of this vitamin A in fish liver oils and multivitamin formulations has been stressed; for its purification and estimation, chromatographic techniques involving column, partition and paper chromatography, have been reviewed. It has been recommended that Indian fish liver oils should be characterised in terms of the biologically active vitamin A; collaborative research effort to achieve this has been suggested.

  15. 化工型空分设备内压缩流程选择%Selection of inner compression process for chemical type air separation plant

    Institute of Scientific and Technical Information of China (English)

    蒋旭

    2011-01-01

    介绍化工型空分设备的3种典型内压缩流程形式:空气循环单泵流程、空气循环双泵流程、氮气循环单泵流程,结合内压缩流程空分设备的一般考核标准,比较了3种流程形式的流程设计组织、综合能耗、精馏效果、运行安全、操作维护等方面,说明用户应合理选择适合产品规格要求的内压缩空分流程。%Here, 3 typical types of inner compression process for chemical type air separation plant are introduced: Air circulation single-pump process, air circulation dual-pump process, and nitrogen circulation single-pump process, and in combination with the general examination standards of inner compression process air separation plant the process design organization, comprehensive energy consumption, distillation effect, operation safety, operation and maintenance of the 3 types of process are compared, which indicates that the user shall rationally select the inner compression air separation process which meets the product specification.

  16. Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

    Science.gov (United States)

    Ouertani, Rachid; Hamdi, Abderrahmen; Amri, Chohdi; Khalifa, Marouan; Ezzaouia, Hatem

    2014-10-01

    In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films.

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

    International Nuclear Information System (INIS)

    Transparent conductive Ga-doped ZnO thin films were deposited onto glass substrates by a low-cost aerosol assisted chemical vapour deposition technique and the effect of gallium content on the ZnO film growth behaviour and opto-electronic properties was systematically investigated. It is found that, upon increasing Ga addition, the ZnO film crystallinity exhibits a continuous reduction in quality associated with the preferential orientation transformed from (002) to (102). The (002) oriented samples had a microstructure of parallel columnar grains while the (102) oriented coating was thickened by overlapping particles. The ZnO:Ga coatings exhibit high carrier concentration (up to 4.1 × 1020 cm−3) but low carrier mobility (up to 0.8 cm2 V−1 s−1), resulting in a minimum resistivity value of 2.3 × 10−2 Ω cm. The inferior carrier mobility performance could result from a profound ionized and neutral impurity scattering effect. Good visible transmittance (≈ 70–80%) is observed in these ZnO:Ga films and samples with higher carrier density present better infrared reflection performance (up to 37.2% at 2500 nm). - Highlights: • Aerosol assisted chemical vapour deposition of doped zinc oxide thin films • Gallium doping and opto-electronic properties systemically investigated • Growth mechanism changed by % gallium incorporation

  18. Graphene synthesis by laser-assisted chemical vapor deposition on Ni plate and the effect of process parameters on uniform graphene growth

    International Nuclear Information System (INIS)

    A fast, simple technique was developed to fabricate few-layer graphene films at ambient pressure and room temperature by laser-assisted chemical vapor deposition on polycrystalline Ni plates. Laser scanning speed was found as the most important factor in the production of few-layer graphene. The quality of graphene films was controlled by varying the laser power. Uniform graphene ribbons with a width of 1.5 mm and a length of 16 mm were obtained at a scanning speed of 1.3 mm/s and a laser power of 600 W. The developed technique provided a promising application of a high-power laser system to fabricate a graphene film. - Highlights: • Uniform few-layer graphene was fabricated at room temperature and ambient conditions. • Laser-assisted chemical vapor deposition was used to grow the layers in a few seconds. • The effect of process parameters on graphene growth was discussed. • This cost effective method could facilitate the integration of graphene in electronic devices

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-01

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

  20. On titanium dioxide thin films growth from the direct current electric field assisted chemical vapour deposition of titanium (IV) chloride in toluene

    International Nuclear Information System (INIS)

    Titanium dioxide thin films were deposited from the aerosol assisted chemical vapour deposition reaction of titanium tetrachloride in toluene (1 M) at 600 °C and 5 L min−1. Direct current electric fields were applied and increased in a range of 0 to 30 V during the reaction. Changes in particle size, agglomeration and particle shape were observed. Raman spectroscopy analysis revealed different composition of anatase and rutile and crystal phase depending on the field strength applied. The photocatalytic activity was calculated from the half-life or time needed by the films to degrade 50% Resazurin dye-ink initial concentration. High photocatalytic performance with high anatase content (98.3%) was observed with half-life values of 3.9 min. Deposited films with pure content in rutile showed better photocatalytic performance than films with mix of crystal phases with anatase content below 40%. - Highlights: • Electric field assisted chemical vapour deposition used to synthesis titania thin films. • Significant alterations to crystallographic orientation and microstructure observed • Order of magnitude reduction in half life of dye degradation obtainable

  1. Solid-State Spun Fibers from 1 mm Long Carbon Nanotube Forests Synthesized by Water-Assisted Chemical Vapor Deposition

    Science.gov (United States)

    Zhang, Shanju; Zhu, Lingbo; Minus, Marilyn L.; Chae, han Gi; Jagannathan, Sudhakar; Wong, Ching-Ping; Kowalik, Janusz; Roberson, Luke B.; Kumar, Satish

    2007-01-01

    In this work, we report continuous carbon nanotube fibers dry-drawn directly from water-assisted CVD grown forests with millimeter scale length. As-drawn nanotube fibers exist as aerogel and can be transformed into more compact fibers through twisting or densification with a volatile liquid. Nanotube fibers are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman microscopy and wide-angle X-ray diffraction (WAXD). Mechanical behavior and electrical conductivity of the post-treated nanotube fibers are investigated.

  2. Reviewing Some Crucial Concepts of Gibbs Energy in Chemical Equilibrium Using a Computer-Assisted, Guided-Problem-Solving Approach

    Science.gov (United States)

    Borge, Javier

    2015-01-01

    G, G°, ?rG, ?rG°, ?G, and ?G° are essential quantities to master the chemical equilibrium. Although the number of publications devoted to explaining these items is extremely high, it seems that they do not produce the desired effect because some articles and textbooks are still being written with some of these quantities that appear to be…

  3. Co-assembly of CdTe and Fe3O4 with molecularly imprinted polymer for recognition and separation of endocrine disrupting chemicals

    Science.gov (United States)

    Chang, Limin; Chen, Shaona; Chu, Jia; Li, Xin

    2013-11-01

    In this study, we present a general protocol to fabricate imprinting matrix co-loaded with CdTe quantum dots and Fe3O4 nanoparticles for the recognition of endocrine disrupting chemicals (EDCs). The resultant composites were characterized by transmission electron microscopy, fluorescence spectroscopy, and energy dispersive spectroscopy. The materials have been demonstrated to be characterized with spherical shape with a saturation magnetization value of 1.7 emu g-1. Furthermore, the rebinding experiments show that the resultant materials have greater affinity and selectivity towards p-nitrophenol (model EDCs) over structurally related compounds. We believe that the effective method proposed in this work might provide a platform to prepare magnetic and fluorescent molecularly imprinted polymers for the recognition and separation of EDCs.

  4. Unique battery with an active membrane separator having uniform physico-chemically functionalized ion channels and a method making the same

    Science.gov (United States)

    Gerald, II, Rex E.; Ruscic, Katarina J.; Sears, Devin N.; Smith, Luis J.; Klingler, Robert J.; Rathke, Jerome W.

    2012-02-21

    The invention relates to a unique battery having an active, porous membrane and method of making the same. More specifically the invention relates to a sealed battery system having a porous, metal oxide membrane with uniform, physicochemically functionalized ion channels capable of adjustable ionic interaction. The physicochemically-active porous membrane purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

  5. Application of chemical, biological and membrane separation processes in textile industry with recourse to zero effluent discharge--a case study.

    Science.gov (United States)

    Nandy, T; Dhodapkar, R S; Pophali, G R; Kaul, S N; Devotta, S

    2005-09-01

    Environmental concerns associated with textile processing had placed the textile sector in a Southern State of India under serious threat of survival. The textile industries were closed under the orders of the Statutory Board for reason of inadequate compliance to environmental discharge norms of the State for the protection of the drinking water source of the State capital. In compliance with the direction of the Board for zero effluent discharge, advanced treatment process have been implemented for recovery of boiler feed quality water with recourse to effluent recycling/reuse. The paper describes to a case study on the adequacy assessment of the full scale effluent treatment plant comprising chemical, biological and filtration processes in a small scale textile industry. In addition, implementation of measures for discernable improvement in the performance of the existing units through effective operation & maintenance, and application of membrane separation processes leading to zero effluent discharge is also highlighted. PMID:16196413

  6. Structural and XPS studies of PSi/TiO{sub 2} nanocomposites prepared by ALD and Ag-assisted chemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Iatsunskyi, Igor, E-mail: yatsunskiy@gmail.com [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Kempiński, Mateusz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 (Poland); Nowaczyk, Grzegorz; Jancelewicz, Mariusz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Pavlenko, Mykola [Department of Experimental Physics, Odessa National I.I. Mechnikov University, 42, Pastera Str., 65023 Odessa (Ukraine); Załęski, Karol [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Jurga, Stefan [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland)

    2015-08-30

    Highlights: • Porous silicon/TiO{sub 2} nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO{sub 2} nanocomposites were established. • Valence-band XPS maximums for PSi/TiO{sub 2} nanocomposites were found and analyzed. - Abstract: PSi/TiO{sub 2} nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO{sub 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{sub 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{sub 2} anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO{sub 2} nanocomposites electronic structure. Surface defects states of Ti{sup 3+} at PSi/TiO{sub 2} nanocomposites were identified by analyzing of XPS valence band spectra.

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

    Science.gov (United States)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-08-01

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

  8. Study and application of ion chromatography and activation analysis without chemical separation for the determination of sodium and potassium in muscle tissues

    International Nuclear Information System (INIS)

    The simultaneous determination of Na and K in small amounts of muscular tissue by use of two methods, namely activation analysis and ion chromatography, is presented. For the activation analysis the samples were irradiated for 30 minutes in a 5 X 1011n cm sup(-)2 s sup(-)1 flux. The induced activities of 24Na and 42K were determined, without chemical separation, using a Ge(Li) detector equipped with a 4096 channel analyser on-line with a computer. The gamma ray spectra registered from the samples and standards were analysed and compared by the computer. For the ion chromatography analysis the samples and standards in solution were injected into the apparatus. The ions were separated by an ion-exchange system of columns and the concentrations were measured by conductivity. In addition, the two analytical methods were compared in regard to sensitivity, precision and accuracy as well as simplicity, cost and working time involved in the analysis. From the point of view of the reliability of the results, both techniques proved to be excelent and might be of great value in medical research. (Author)

  9. Differential chemical derivatization integrated with chromatographic separation for analysis of isomeric sialylated N-glycans: a nano-hydrophilic interaction liquid chromatography-MS platform.

    Science.gov (United States)

    Tousi, Fateme; Bones, Jonathan; Hancock, William S; Hincapie, Marina

    2013-09-01

    MS analysis of sialylated glycans is challenging due to their low ionization efficiency in positive ion mode as well as the possibility of in-source fragmentation. Chemical derivatization strategies have been developed to address this issue focused on removal of the labile acidic proton prior to MS analysis. Highly sialylated negatively charged glycans also exhibit high retention and unsatisfactory separation efficiency when analyzed by hydrophilic interaction liquid chromatography (HILIC) due to their high polarity. Here, we combined linkage specific derivatization of sialic acids by reaction with the condensation reagent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) in methanol with nanoscale liquid chromatographic separation prior to accurate mass Orbitrap MS analysis. Coupling DMT-MM charge neutralization of sialic acids with nano-HILIC-Orbitrap-MS not only allows for linkage specific characterization of sialylated glycans directly from the precursor mass but also improves the preceding HILIC separation by increasing the hydrophobicity and altering the selectivity of the oligosaccharide analytes. We focused on the trisialylated N-glycan fraction from haptoglobin and human plasma, enriched using weak anion exchange chromatography, as this trisialylated fraction has been linked with cancer associated changes in the serum N-glycome. The developed methodology was applied to investigate whether structural alterations in this oligosaccharide pool, enriched from the sera of pathological stage and sex matched patients bearing lung, breast, ovarian, pancreatic, or gastric cancer, demonstrate any degree of cancer specificity or whether changes in expression levels are purely cancer associated. The results of this pilot study indicate limited degrees of cancer specificity, particularly for pancreatic cancer, based on alterations in the relative abundance of specific trisialylated isomers. PMID:23901877

  10. Calibration of Rainfall-Runoff Model by Referring to Hydrological Separation of Runoff Components using Chemical and Isotopic Characteristics of Discharge

    Science.gov (United States)

    Chikamori, H.

    2008-12-01

    Calibration of Rainfall-Runoff Model by Referring to Hydrological Separation of Runoff Components using Chemical and Isotopic Characteristics of Discharge Hidetaka Chikamori Graduate School of Environmental Science, Okayama University, JAPAN A rainfall-runoff model is generally calibrated by minimizing error in calculated runoff using records of hydrological components, that is, observed rainfall, discharge and observed or estimated evapotranpiration. However, calibration using only hydrological components sometimes produces a model with strange structure that does not reflect physical properties of an objective basin. It is probably due to error in referred hydrological records. In this study, the author calibrated a rainfall runoff model using not only hydrological record but also chemical and isotopic data of discharge so as to obtain a reasonably structured model from multiple viewpoints. Besides, the model structure was improved in order to simulate isotopic characteristics well. It is well known that ratio of surface flow in total flow can be estimated by change in concentration of cation or anion. Relative concentration of 18O, δ18O is well used for separating runoff of retained water in soil as "old water" from total runoff. A Long-and-Short Term Tank Model (LST2 Model) was applied to three Hinoki Cypress catchments in Mie experimental basin located in the middle of Japan. One of these catchments is of well-maintained planted forest, and two are of poor-maintained planted. A model was calibrated by Differential Evolution for each catchment using hydrological data, concentration of K+ and δ18O. In these catchments, Gomi et al (2008) showed that concentration of K+ well expresses ratio of surface runoff to total runoff, and that δ18O subsurface runoff to total runoff. The results show that an original version of LST2 Model cannot simulated delayed subsurface flow ratio estimated by δ18O, although it well simulates surface flow ratio estimated by

  11. Successful definition of nanowire and porous Si regions of different porosity levels by regular positive photoresist using metal-assisted chemical etching

    International Nuclear Information System (INIS)

    A simple and efficient method for selective formation of porous Si areas using regular photoresist as a masking layer is presented. Such a simple masking layer is sufficient to create a wide range of porosity levels through metal-assisted chemical etching (MaCE) using platinum, palladium and silver nanoparticles. Reproducible porous areas with a minimum feature size of 5 µm were produced on Si wafers. The pore size and height are the functions of the etching time and type of nanoparticles. Using Ag nanopaticles we have been able to obtain Si nanowires of about 30 µm height. Based on these results, a combination of positive photoresist and MaCE seems to be a reliable way for micron and submicron patterning of nanowire and porous areas on Si wafers, which is simple, inexpensive and compatible with integrated circuit fabrication techniques

  12. Thin films of tin(II) sulphide (SnS) by aerosol-assisted chemical vapour deposition (AACVD) using tin(II) dithiocarbamates as single-source precursors

    Science.gov (United States)

    Kevin, Punarja; Lewis, David J.; Raftery, James; Azad Malik, M.; O'Brien, Paul

    2015-04-01

    The synthesis of the asymmetric dithiocarbamates of tin(II) with the formula [Sn(S2CNRR')2] (where R=Et, R'=n-Bu (1); R=Me, R'=n-Bu (2); R=R'=Et (3)) and their use for the deposition of SnS thin films by aerosol-assisted chemical vapour deposition (AACVD) is described. The effects of temperature and the concentration of the precursors on deposition were investigated. The stoichiometry of SnS was best at higher concentrations of precursors (250 mM) and at 450 °C. The direct electronic band gap of the SnS produced by this method was estimated from optical absorbance measurements as 1.2 eV. The composition of films was confirmed by powder X-ray diffraction (p-XRD) and energy dispersive analysis of X-rays (EDAX) spectroscopy.

  13. Preparation of high-quality hydrogenated amorphous silicon film with a new microwave electron cyclotron resonance chemical vapour deposition system assisted with hot wire

    Institute of Scientific and Technical Information of China (English)

    Zhu Xiu-Hong; Chen Guang-Hua; Yin Sheng-Yi; Rong Yan-Dong; Zhang Wen-Li; Hu Yue-Hui

    2005-01-01

    The preparation of high-quality hydrogenated amorphous silicon (a-Si:H) film with a new microwave electron cyclotron resonance-chemical vapour deposition (MWECR-CVD) system assisted with hot wire is presented. In this system the hot wire plays an important role in perfecting the microstructure as well as improving the stability and the optoelectronic properties of the a-Si:H film. The experimental results indicate that in the microstructure of the a-Si:H film, the concentration of dihydride is decreased and a trace of microcrystalline occurs, which is useful to improve its stability, and that in the optoelectronic properties of the a-Si:H film, the deposition rate reaches above 2.0nm/s and the photosensitivity increases up to 4.71× 105.

  14. Structural and photoluminescent properties of nanowires formed by the metal-assisted chemical etching of monocrystalline silicon with different doping level

    International Nuclear Information System (INIS)

    Silicon-nanowire layers grown by the metal-assisted chemical etching of (100)-oriented p-type monocrystalline silicon substrates with a resistivity of 10 and 0.001 Ω · cm are studied by electron microscopy, Raman scattering, and photoluminescence measurements. It is established that nanowires grown on lightly doped substrates are structurally nonporous and formed as crystalline cores covered by nanocrystals 3–5 nm in dimensions. Nanowires grown on heavily doped substrates are structurally porous and contain both small nanocrystals and coarser crystallites with equilibrium charge carriers that influence interband radiative recombination. It is found that the photoluminescence intensity of nanowires in the spectral range 1.3–2.0 eV depends on the presence of molecular oxygen

  15. Structural and photoluminescent properties of nanowires formed by the metal-assisted chemical etching of monocrystalline silicon with different doping level

    Energy Technology Data Exchange (ETDEWEB)

    Georgobiani, V. A., E-mail: v.georgobiani@gmail.com; Gonchar, K. A.; Osminkina, L. A.; Timoshenko, V. Yu. [Lomonosov Moscow State University, Faculty of Physics (Russian Federation)

    2015-08-15

    Silicon-nanowire layers grown by the metal-assisted chemical etching of (100)-oriented p-type monocrystalline silicon substrates with a resistivity of 10 and 0.001 Ω · cm are studied by electron microscopy, Raman scattering, and photoluminescence measurements. It is established that nanowires grown on lightly doped substrates are structurally nonporous and formed as crystalline cores covered by nanocrystals 3–5 nm in dimensions. Nanowires grown on heavily doped substrates are structurally porous and contain both small nanocrystals and coarser crystallites with equilibrium charge carriers that influence interband radiative recombination. It is found that the photoluminescence intensity of nanowires in the spectral range 1.3–2.0 eV depends on the presence of molecular oxygen.

  16. Synthesis, structural characterization and optical properties of multilayered Yttria-stabilized ZrO2 thin films obtained by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Multilayered Yttria-stabilized zirconium (YSZ) oxide thin films were synthesized by aerosol assisted chemical vapour deposition onto borosilicate glass substrate. The film consisted of a periodic stack of several YSZ layer pairs. Each pair was composed of layers, a few nanometers thick, of the same composition but different density. Optically the multilayered microstructure correspond to alternating layers of high (dense layer) and low (porous layer) refraction index. The microstructure was analysed by electron and atomic force microscopy. Optical properties were evaluated by reflectance spectroscopy, and associated with the cross sectional microstructure of the films. The measured effective refractive index of the films deviates from bulk value. The discrepancy can be explained by the multilayered structure of the film

  17. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal Bin

    2015-12-22

    The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  18. Tannase-mediated biotransformation assisted separation and purification of theaflavin and epigallocatechin by high speed counter current chromatography and preparative high performance liquid chromatography: A comparative study.

    Science.gov (United States)

    Xia, Guobin; Lin, Chunfang; Liu, Songbai

    2016-09-01

    A large scale isolation and purification of theaflavin (TF) and epigallocatechin (EGC) has been successfully developed by tannase-mediated biotransformation combining high-speed countercurrent chromatography. After tannase hydrolysis of a commercially available theaflavins extract (TE), the content of TF and EGC in tannase-mediated biotransformation product (TBP) achieved approximately 3 times enrichment. SEM studies revealed smooth tannase biotransformation and the possibility of recovery of the tannase. A single 1.5 hours' HSCCC separation for TF and EGC employing a two-phase solvent system could simultaneously produce 180.8 mg of 97.3% purity TF and 87.5 mg of 97.3% purity EGC. However, a preparative HPLC separation of maximum injection volume containing 120 mg TBP prepared 11.2 mg TF of 94.9% purity and 7.7 mg EGC of 89.9% purity. HSCCC separation demonstrated significant advantages over Prep HPLC in terms of sample loading size, separation time, environmental friendly solvent systems, and the production. PMID:27389804

  19. Direct synthesis of large area graphene on insulating substrate by gallium vapor-assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Katsuhisa, E-mail: k.murakami@bk.tsukuba.ac.jp; Hiyama, Takaki; Kuwajima, Tomoya; Fujita, Jun-ichi [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573 (Japan); Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan); Tanaka, Shunsuke; Hirukawa, Ayaka [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573 (Japan); Kano, Emi [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573 (Japan); National Institute for Materials Science, Tsukuba 305-0047 (Japan); Takeguchi, Masaki [National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    2015-03-02

    A single layer of graphene with dimensions of 20 mm × 20 mm was grown directly on an insulating substrate by chemical vapor deposition using Ga vapor catalysts. The graphene layer showed highly homogeneous crystal quality over a large area on the insulating substrate. The crystal quality of the graphene was measured by Raman spectroscopy and was found to improve with increasing Ga vapor density on the reaction area. High-resolution transmission electron microscopy observations showed that the synthesized graphene had a perfect atomic-scale crystal structure within its grains, which ranged in size from 50 nm to 200 nm.

  20. Direct synthesis of large area graphene on insulating substrate by gallium vapor-assisted chemical vapor deposition

    International Nuclear Information System (INIS)

    A single layer of graphene with dimensions of 20 mm × 20 mm was grown directly on an insulating substrate by chemical vapor deposition using Ga vapor catalysts. The graphene layer showed highly homogeneous crystal quality over a large area on the insulating substrate. The crystal quality of the graphene was measured by Raman spectroscopy and was found to improve with increasing Ga vapor density on the reaction area. High-resolution transmission electron microscopy observations showed that the synthesized graphene had a perfect atomic-scale crystal structure within its grains, which ranged in size from 50 nm to 200 nm

  1. Carbon diffusion in uncoated and titanium nitride coated iron substrates during microwave plasma assisted chemical vapor deposition of diamond

    International Nuclear Information System (INIS)

    Auger Electron Spectroscopy has been employed to investigate the effectiveness of thin films of TiN as barriers to carbon diffusion during Chemical Vapor Deposition (CVD) of diamond onto Fe substrates. Auger Depth Profiling was used to monitor the C concentration in the TiN layer, through the interface and into the substrate both before and after CVD diamond deposition. The results show that a layer of TiN only 250 Angstroems thick is sufficient to inhibit soot formation on the Fe surface and C diffusion into the Fe bulk. 14 refs., 4 figs

  2. Gas-phase separation of drugs and metabolites using modifier-assisted differential ion mobility spectrometry hyphenated to liquid extraction surface analysis and mass spectrometry.

    Science.gov (United States)

    Porta, Tiffany; Varesio, Emmanuel; Hopfgartner, Gérard

    2013-12-17

    The present work describes an alternative generic approach to LC-MS for the analysis of drugs of abuse as well as their metabolites in post-mortem tissue samples. The platform integrates liquid extraction surface analysis (LESA) for analytes tissue extraction followed by differential ion mobility spectrometry (DMS) mass spectrometry for analytes gas phase separation. Detection is performed on a triple quadrupole linear ion trap using the selected reaction monitoring mode for quantification as well as product ion scan mode for structural confirmatory analyses. The major advantages of the platform are that neither chromatographic separation nor extensive sample preparation are required. In DMS the combination of a high separation voltage (i.e., up to 4 kV) together with organic modifiers (e.g., alcohols, acetonitrile, acetone) added in the drift gas is required to achieve the separation of isomeric metabolites, such as the ones of cocaine and tramadol. DMS also separates morphine from its glucuronide metabolites, which allows for preventing the overestimation of morphine in case of fragmentation of the glucuronides in the atmospheric-to-vacuum interface of the mass spectrometer. Cocaine, opiates, opioids, amphetamines, benzodiazepines and several of their metabolites could be identified in post-mortem human kidney and muscle tissue based on simultaneous screening and confirmatory analysis in data-dependent acquisition mode using an analyte-dependent compensation voltage to selectively transmit ions through the DMS cell to the mass analyzer. Quantitative performance of the LESA-DMS-MS platform was evaluated for cocaine and two of its metabolites spotted onto a tissue section using deuterated internal standard. Analyte's responses were linear from 2 to 1000 pg on tissue corresponding to a limit of detection in the order of nanograms of analyte per gram of tissue. Accuracy and precision based on QC sample was found to be less than 10%. Replicate analyses of cocaine and

  3. Optimization for ultrasound-assisted extraction of polysaccharides with chemical composition and antioxidant activity from the Artemisia sphaerocephala Krasch seeds.

    Science.gov (United States)

    Zheng, Quan; Ren, Daoyuan; Yang, Nana; Yang, Xingbin

    2016-10-01

    Artemisia sphaerocephala Krasch seeds polysaccharides have been reported to have a variety of important biological activities. However, effective extraction of Artemisia sphaerocephala Krasch seeds polysaccharides is still an unsolved issue. In this study, the orthogonal rotatable central composite design was employed to optimize ultrasound-assisted extraction conditions of Artemisia sphaerocephala Krasch seeds polysaccharides. Based on a single-factor analysis method, ultrasonic power, extraction time, solid-liquid ratio and extraction temperature were shown to significantly affect the yield of polysaccharides extracted from the A. sphaerocephala Krasch seeds. The optimal conditions for extraction of Artemisia sphaerocephala Krasch seeds polysaccharides were determined as following: ultrasonic power 243W, extraction time 125min, solid-liquid ratio 64:1 and extraction temperature 64°C, where the experimental yield was 14.78%, which was well matched with the predicted value of 14.81%. Furthermore, ASKP was identified as a typical heteropolysaccharide with d-galacturonic acid (38.8%) d-galactose (20.2%) and d-xylose (15.5%) being the main constitutive monosaccharides. Moreover, Artemisia sphaerocephala Krasch seeds polysaccharides exhibited high total reducing power and considerable scavenging activities on DPPH, hydroxyl and superoxide radicals, in a concentration-dependent manner in vitro. PMID:27316764

  4. Quantum dots assisted photocatalysis for the chemiluminometric determination of chemical oxygen demand using a single interface flow system

    International Nuclear Information System (INIS)

    Highlights: → A novel flow method for the determination of chemical oxygen demand is proposed. → CdTe nanocrystals are irradiated with UV light to generate strong oxidizing species. → Reactive species promote a fast catalytic degradation of organic matter. → Luminol is used as a chemiluminescence probe for indirect COD assessment. → A single interface flow system was implemented to automate the assays. - Abstract: A novel flow method for the determination of chemical oxygen demand (COD) is proposed in this work. It relies on the combination of a fully automated single interface flow system, an on-line UV photocatalytic unit and quantum dot (QD) nanotechnology. The developed approach takes advantage of CdTe nanocrystals capacity to generate strong oxidizing species upon irradiation with UV light, which fostered a fast catalytic degradation of the organic compounds. Luminol was used as a chemiluminescence (CL) probe for indirect COD assessment, since it is easily oxidized by the QD generated species yielding a strong CL emission that is quenched in the presence of the organic matter. The proposed methodology allowed the determination of COD concentrations between 1 and 35 mg L-1, with good precision (R.S.D. -1. The procedure was applied to the determination of COD in wastewater certified reference materials and the obtained results showed an excellent agreement with the certified values.

  5. Aligned synthesis of multi-walled carbon nanotubes with high purity by aerosol assisted chemical vapor deposition: Effect of water vapor

    International Nuclear Information System (INIS)

    Aligned multi-walled carbon nanotubes (MWCNTs) with high purity and bulk yield were achieved on a silicon substrate by an aerosol-assisted chemical vapor deposition. The introduction of specific amounts of water vapor played a key role in in situ controlling the purity and surface defects of the nanotubes. The morphology, surface quality and structure of MWCNTs were characterized by secondary and backscattered electron imaging in a field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Crystallinity and defects of the MWCNTs' were investigated by high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. In this work, water vapor was found to provide a weak oxidative environment, which enhanced and purified the MWCNTs' growth. However, excessive water vapor would inhibit the MWCNTs growth with a poor surface quality. In addition, it has been found that the surface morphology of the CNTs can be modified intentionally through producing some surface defects by tuning the amount of the water vapor, which may offer more nucleation sites on the chemically inert CNT surface for various applications such as catalyst support.

  6. Microwave-assisted catalytic fast pyrolysis of biomass for bio-oil production using chemical vapor deposition modified HZSM-5 catalyst.

    Science.gov (United States)

    Zhang, Bo; Zhong, Zhaoping; Chen, Paul; Ruan, Roger

    2015-12-01

    Chemical vapor deposition with tetra-ethyl-orthosilicate as the modifier was applied to deposit the external acid sites of HZSM-5, and the modified HZSM-5 samples were used for the microwave-assisted catalytic fast pyrolysis (MACFP) of biomass for bio-oil production. The experimental results showed that the external acid sites of HZSM-5 decreased significantly when SiO2 deposited amount increased from 0% to 5.9%. For product distribution, the coke yield decreased, the oil fraction yield decreased at first and then increased, and the yields of water and gas first increased and then decreased over the range of SiO2 deposited amount studied. For chemical compositions in oil fraction, the relative contents of aliphatic hydrocarbons, aromatic hydrocarbons and oxygen-containing aromatic compounds first increased to maximum values and then decreased, while the relative content of oxygen-containing aliphatic compounds first decreased and then increased with increasing SiO2 deposited amount. PMID:26318925

  7. Ultrasonic-assisted synthesis of ZrO2 nanoparticles and their application to improve the chemical stability of Nafion membrane in proton exchange membrane (PEM) fuel cells.

    Science.gov (United States)

    Taghizadeh, Mohammad Taghi; Vatanparast, Morteza

    2016-12-01

    Zirconium dioxide (ZrO2) nanoparticles were fabricated successfully via ultrasonic-assisted method using ZrO(NO3)2·H2O, ethylenediamine and hydrazine as precursors in aqueous solution. Morphology, structure and composition of the obtained products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and diffuse reflectance spectroscopy (DRS). Then, the synthesized nanoparticles were used to prepare Nafion/ZrO2 nanocomposite membranes. The properties of the membranes were studied by ion exchange capacity (IEC) proton conductivity (σ), thermal stability and water uptake measurements. The ex-situ Fenton's test was used to investigate the chemical stability of the membranes. From our results, compared with Nafion membrane, the nanocomposite membrane exhibited lower fluoride release and weight loss. Therefore, it can concluded that Nafion/ZrO2 nanocomposite exhibit more chemical stability than the pure Nafion membrane. ATR-FTIR spectra and SEM surface images of membranes also confirm these results. PMID:27544443

  8. Fate of 17β-Estradiol as a model estrogen in source separated urine during integrated chemical P recovery and treatment using partial nitritation-anammox process.

    Science.gov (United States)

    Huang, Pei; Mukherji, Sachiyo T; Wu, Sha; Muller, James; Goel, Ramesh

    2016-10-15

    Recently, research on source separation followed by the treatment of urine and/or resource recovery from human urine has shown promise as an emerging management strategy. Despite contributing only 1% of the total volume of wastewater, human urine contributes about 80% of the nitrogen, 70% of the potassium, and up to 50% of the total phosphorus in wastewater. It is also a known fact that many of the micropollutants, especially selected estrogens, get into municipal wastewater through urine excretion. In this research, we investigated the fate of 17β-estradiol (E2) as a model estrogen during struvite precipitation from synthetic urine followed by the treatment of urine using a partial nitritation-anammox (PN/A) system. Single-stage and two-stage suspended growth PN/A configurations were used to remove the nitrogen in urine after struvite precipitation. The results showed an almost 95% phosphorous and 5% nitrogen recovery/removal from the synthetic urine due to struvite precipitation. The single and two stage PN/A processes were able to remove around 50% and 75% of ammonia and nitrogen present in the post struvite urine solution, respectively. After struvite precipitation, more than 95% of the E2 remained in solution and the transformation of E2 to E1 happened during urine storage. Most of the E2 removal that occurred during the PN/A process was due to sorption on the biomass and biodegradation (transformation of E2 to E1, and slow degradation of E1 to other metabolites). These results demonstrate that a combination of chemical and biological unit processes will be needed to recover and manage nutrients in source separated urine. PMID:27566951

  9. 33rd Actinide Separations Conference

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, L M; Wilk, P A

    2009-05-04

    Welcome to the 33rd Actinide Separations Conference hosted this year by the Lawrence Livermore National Laboratory. This annual conference is centered on the idea of networking and communication with scientists from throughout the United States, Britain, France and Japan who have expertise in nuclear material processing. This conference forum provides an excellent opportunity for bringing together experts in the fields of chemistry, nuclear and chemical engineering, and actinide processing to present and discuss experiences, research results, testing and application of actinide separation processes. The exchange of information that will take place between you, and other subject matter experts from around the nation and across the international boundaries, is a critical tool to assist in solving both national and international problems associated with the processing of nuclear materials used for both defense and energy purposes, as well as for the safe disposition of excess nuclear material. Granlibakken is a dedicated conference facility and training campus that is set up to provide the venue that supports communication between scientists and engineers attending the 33rd Actinide Separations Conference. We believe that you will find that Granlibakken and the Lake Tahoe views provide an atmosphere that is stimulating for fruitful discussions between participants from both government and private industry. We thank the Lawrence Livermore National Laboratory and the United States Department of Energy for their support of this conference. We especially thank you, the participants and subject matter experts, for your involvement in the 33rd Actinide Separations Conference.

  10. Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M23C6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M23C6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

  11. A comparison of the efficacy of organic and mixed-organic polymers with polyaluminium chloride in chemically assisted primary sedimentation (CAPS).

    Science.gov (United States)

    De Feo, G; Galasso, M; Landi, R; Donnarumma, A; De Gisi, S

    2013-01-01

    CAPS is the acronym for chemically assisted primary sedimentation, which consists of adding chemicals to raw urban wastewater to increase the efficacy of coagulation, flocculation and sedimentation. The principal benefits of CAPS are: upgrading of urban wastewater treatment plants; increasing efficacy of primary sedimentation; and the major production of energy from the anaerobic digestion of primary sludge. Metal coagulants are usually used because they are both effective and cheap, but they can cause damage to the biological processes of anaerobic digestion. Generally, biodegradable compounds do not have these drawbacks, but they are comparatively more expensive. Both metal coagulants and biodegradable compounds have preferential and penalizing properties in terms of CAPS application. The problem can be solved by means of a multi-criteria analysis. For this purpose, a series of tests was performed in order to compare the efficacy of several organic and mixed-organic polymers with that of polyaluminium chloride (PACl) under specific conditions. The multi-criteria analysis was carried out coupling the simple additive weighting method with the paired comparison technique as a tool to evaluate the criteria priorities. Five criteria with the following priorities were used: chemical oxygen demand (COD) removal > turbidity, SV60 > coagulant dose, and coagulant cost. The PACl was the best alternative in 70% of the cases. The CAPS process using PACl made it possible to obtain an average COD removal of 68% compared with 38% obtained, on average, with natural sedimentation and 61% obtained, on average, with the best PACl alternatives (cationic polyacrylamide, natural cationic polymer, dicyandiamide resin). PMID:24191462

  12. Chemically assisted ion beam etching of laser diode facets on nonpolar and semipolar orientations of GaN

    Science.gov (United States)

    Kuritzky, L. Y.; Becerra, D. L.; Saud Abbas, A.; Nedy, J.; Nakamura, S.; DenBaars, S. P.; Cohen, D. A.

    2016-07-01

    We demonstrate a vertical (rate. Co-loaded studies showed similar etch rates of ∼60 nm min‑1 for (20\\bar{2}\\bar{1}),(20\\bar{2}1), and m-plane orientations. The etched surfaces of LD facets on these orientations are chemically dissimilar (Ga-rich versus N-rich), but were visually indistinguishable, thus confirming the negligible orientation dependence of the etch. Continuous-wave blue LDs were fabricated on the semipolar (20\\bar{2}\\bar{1}) plane to compare CAIBE and reactive ion etch (RIE) facet processes. The CAIBE process resulted in LDs with lower threshold current densities due to reduced parasitic mirror loss compared with the RIE process. The LER, degree of verticality, and model of the 1D vertical laser mode were used to calculate a maximum uncoated facet reflection of 17% (94% of the nominal) for the CAIBE facet. The results demonstrate the suitability of CAIBE for forming high quality facets for high performance nonpolar and semipolar III-N LDs.

  13. Periodic nanostructuring of Er/Yb-codoped IOG1 phosphate glass by using ultraviolet laser-assisted selective chemical etching

    International Nuclear Information System (INIS)

    The patterning of submicron period (≅500 nm) Bragg reflectors in the Er/Yb-codoped IOG1 Schott, phosphate glass is demonstrated. A high yield patterning technique is presented, wherein high volume damage is induced into the glass matrix by exposure to intense ultraviolet 213 nm, 150 ps Nd:YAG laser radiation and, subsequently, a chemical development in potassium hydroxide (KOH)/ethylenediamine tetra-acetic acid (EDTA) aqueous solution selectively etches the exposed areas. The electronic changes induced by the 213 nm ultraviolet irradiation are examined by employing spectrophotometric measurements, while an estimation of the refractive index changes recorded is provided by applying Kramers-Kronig transformation to the absorption change data. In addition, real time diffraction efficiency measurements were obtained during the formation of the volume damage grating. After the exposure, the growth of the relief grating pattern in time was measured at fixed time intervals and the dependence of the grating depth on the etching time and exposure conditions is presented. The gratings fabricated are examined by atomic and scanning electron microscopies to reveal the relief topology of the structures. Gratings with average depth of 120 nm and excellent surface quality were fabricated by exposing the IOG1 phosphate glass to 36 000 pulses of 208 mJ/cm2 energy density, followed by developing in the KOH/EDTA agent for 6 min

  14. Chemically assisted femtosecond laser machining for applications in LiNbO3 and LiTaO3

    International Nuclear Information System (INIS)

    We introduce and optimize a fabrication procedure that employs both femtosecond laser machining and hydrofluoric acid etching for cutting holes or voids in slabs of lithium niobate and lithium tantalate. The fabricated structures have 3 μm lateral resolution, a lateral extent of at least several millimeters, and cut depths of up to 100 μm. Excellent surface quality is achieved by initially protecting the optical surface with a sacrificial silicon dioxide layer that is later removed during chemical etching. To optimize cut quality and machining speed, we explored various laser-machining parameters, including laser polarization, repetition rate, pulse duration, pulse energy, exposure time, and focusing, as well as scanning, protective coating, and etching procedures. The resulting structures significantly broaden the capabilities of terahertz polaritonics, in which lithium niobate and lithium tantalate are used for terahertz wave generation, imaging, and control. The approach should be applicable to a wide range of materials that are difficult to process by conventional methods. (orig.)

  15. Amino acids separation with the tetracarboxylic derived of the para-ter-butylcalix[4]arene by means of solid-liquid extraction assisted with lanthanides

    International Nuclear Information System (INIS)

    The tetracarboxylic derived of the para-ter-butylcalix[4]arene (B4ACEbL4) does not exist commercially for what was synthesized and characterized at laboratory level. The separation of the L-tyrosine amino acid was studied by means of a solid-liquid extraction system with the B4ACEbL4 as solid phase, in function of ph (2.5-7.5) and contact time (5 and 15 hours) to temperature of 15-17 grades C. Resulted that the ph and the contact time were decisive in the extraction percentage of water tyrosine. The lowest percentage was 49% to ph 4 and the highest percentage was 61% to ph 7.5 with 15 hours of contact. In a contact time of 5 hours the extraction was inferior to 32% (ph 4) and of 47% to ph 6.5. The europium effect (Eu (III)) was studied to ph acid in the tyrosine separation and was found that the tyrosine extraction is not increased neither decomposes in europium presence, this is simultaneously extracted by the calixarene but it does not enter in competition for the calixarene with the amino acid. The separate solid phases: calixarene-tyrosine was analyzed by Far infrared radiation (Fir), Mid-Infrared (Mir) spectroscopy and luminescence to check the tyrosine presence in the separate solids as well as the nature of the connection calixarene-tyrosine. In this way was possible to check the tyrosine presence and to propose the formed molecular species tyrosine-calixarene, those which interact mainly by means of hydrogen connections and Van der Waals forces. The liquid phases before and after the extraction were analyzed by UV-Vis spectrophotometry and luminescence. The Neutron activation analysis was used to determine the europium content in the solid and liquid phases of extractions in europium presence. The tyrosine degradation also shows dependence with the ph, obtaining 88% degradation to the 24 hours to ph 7.5, while to ph 3 is degraded the 54% of tyrosine present in the sample. The europium presence does not affect the tyrosine extraction but if its photo

  16. Determination of Os by isotope dilution-inductively coupled plasma-mass spectrometry with the combination of laser ablation to introduce chemically separated geological samples

    Science.gov (United States)

    Sun, Yali; Ren, Minghao; Xia, Xiaoping; Li, Congying; Sun, Weidong

    2015-11-01

    A method was developed for the determination of trace Os in geological samples by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) with the combination of chemical separation and preconcentration. Samples are digested using aqua regia in Carius tubes, and the Os analyte is converted into volatile OsO4, which is distilled and absorbed with HBr. The HBr solution is concentrated for further Os purification using the microdistillation technique. The purified Os is dissolved in 10 μl of 0.02% sucrose-0.005% H3PO4 solution and then evaporated on pieces of perfluoroalkoxy (PFA) film, resulting in the formation of a tiny object (< 3 × 104 μm2 superficial area). Using LA-ICP-MS measurements, the object can give Os signals at least 100 times higher than those provided by routine solution-ICP-MS while successfully avoiding the memory effect. The procedural blank and detection limit in the developed technique are 3.0 pg and 1.8 pg for Os, respectively when 1 g of samples is taken. Reference materials (RM) are analyzed, and their Os concentrations obtained by isotope dilution are comparable to reference or literature values. Based on the individual RM results, the precision is estimated within the range of 0.6 to 9.4% relative standard deviation (RSD), revealing that this method is applicable to the determination of trace Os in geological samples.

  17. Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave-Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni2+ Ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    M. Makeswari

    2013-01-01

    Full Text Available The preparation of activated carbon (AC from Ricinus communis leaves was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted zinc chloride. Optimized parameters were radiation power of 100 W, radiation time of 8 min, concentration of zinc chloride of 30% by volume, and impregnation time of 24 h, respectively. The surface characteristics of the AC prepared under optimized conditions were examined by pHZPC, SEM-EDAX, XRD, and FTIR. Competitive adsorption of Ni2+ ions on Ricinus communis leaves by microwave assisted zinc chloride chemical activation (ZLRC present in binary and ternary mixture was compared with the single metal solution. The effects of the presence of one metal ion on the adsorption of the other metal ion were investigated. The experimental results indicated that the uptake capacity of one metal ion was reduced by the presence of the other metal ion. The extent of adsorption capacity of the binary and ternary metal ions tested on ZLRC was low (48–69% as compared to single metal ions. Comparisons with the biosorption of Ni2+ ions by the biomass of ZLRC in the binary (48.98–68.41%-~Ni-Cu and 69.76–66.29%-~Ni-Cr and ternary solution (67.32–57.07%-~Ni–Cu and Cr could lead to the conclusion that biosorption of Ni2+ ions was reduced by the influence of Cu2+ and Cr3+ ions. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The adsorption process follows the pseudo-second-order kinetic model.

  18. Cross-stacked carbon nanotubes assisted self-separation of free-standing GaN substrates by hydride vapor phase epitaxy

    Science.gov (United States)

    Wei, Tongbo; Yang, Jiankun; Wei, Yang; Huo, Ziqiang; Ji, Xiaoli; Zhang, Yun; Wang, Junxi; Li, Jinmin; Fan, Shoushan

    2016-06-01

    We report a novel method to fabricate high quality 2-inch freestanding GaN substrate grown on cross-stacked carbon nanotubes (CSCNTs) coated sapphire by hydride vapor phase epitaxy (HVPE). As nanoscale masks, these CSCNTs can help weaken the interface connection and release the compressive stress by forming voids during fast coalescence and also block the propagation of threading dislocations (TDs). During the cool-down process, thermal stress-induced cracks are initiated at the CSCNTs interface with the help of air voids and propagated all over the films which leads to full self-separation of FS-GaN substrate. Raman and photoluminescence spectra further reveal the stress relief and crystalline improvement of GaN with CSCNTs. It is expected that the efficient, low cost and mass-producible technique may enable new applications for CNTs in nitride optoelectronic fields.

  19. Surface morphological and photoelectrochemical studies of ZnS thin films developed from single source precursors by aerosol assisted chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ehsan, Muhammad Ali [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Peiris, T.A. Nirmal; Wijayantha, K.G. Upul [Department of Chemistry, Loughborough University, Loughborough, LE11 3TU (United Kingdom); Khaledi, Hamid [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Ming, Huang Nay [Faculty of Science, Department of Physics, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Misran, Misni; Arifin, Zainudin [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mazhar, Muhammad, E-mail: mazhar42pk@yahoo.com [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

    2013-07-01

    Zinc sulphide (ZnS) thin films have been deposited on fluorine-doped tin oxide-coated conducting glass substrates at 375, 425 and 475 °C temperatures from single source adduct precursors [Zn(S{sub 2}CNCy{sub 2}){sub 2}(py)] (1) [where, Cy = cyclohexyl, py = pyridine] and [Zn{S_2CN(CH_2Ph)(Me)}{sub 2}(py)] (2) [where, Ph = Phenyl, Me = Methyl] using aerosol assisted chemical vapour deposition (AACVD). The precursor complexes have been characterized by microanalysis, infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray single crystal and thermogravimetric analysis. Thermal analysis showed that both precursors (1) and (2) undergo thermal decomposition at 375 °C to produce ZnS residues. The deposited ZnS films have been characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. Scanning electron microscopic studies indicated that the surface morphology of ZnS films strongly depends on the nature of the precursor and the deposition temperature, regardless of marginal variation in thermal stability of the precursors. Direct band gap energies of 3.36 and 3.40 eV have been estimated from the ultraviolet–visible spectroscopy for the ZnS films fabricated from precursors (1) and (2), respectively. The current–voltage characteristics recorded under air mass 1.5 illumination confirmed that the deposited ZnS thin films are photoactive under anodic bias conditions. Furthermore, the photoelectrochemical (PEC) results indicate that these synthesised single source precursors are suitable for obtaining ZnS thin films by AACVD method. The ZnS thin film electrode prepared in this study are very promising for solar energy conversion and optoelectronic applications. The PEC properties of ZnS electrodes prepared from (2) are superior to that of the ZnS electrode prepared from precursor (1). - Highlights: • Synthesis and characterization of zinc dithiocarbamate pyridine adducts. • ZnS photo electrodes have been fabricated using aerosol-assisted

  20. Selective synthesis of large diameter, highly conductive and high density single-walled carbon nanotubes by a thiophene-assisted chemical vapor deposition method on transparent substrates

    Science.gov (United States)

    Li, Jinghua; Otsuka, Keigo; Zhang, Xiao; Maruyama, Shigeo; Liu, Jie

    2016-07-01

    Selective synthesis of single-walled carbon nanotubes (SWNTs) with controlled properties is an important research topic for SWNT studies. Here we report a thiophene-assisted chemical vapor deposition (CVD) method to directly grow highly conductive SWNT thin films on substrates, including transparent ones. By adding low concentration thiophene into the carbon feedstock (ethanol), the as-prepared carbon nanotubes demonstrate an obvious up-shift in the diameter distribution while the single-walled structure is still retained. In the proposed mechanism, the change in the diameter is sourced from the increase in the carbon yield induced by the sulfur-containing compound. Such SWNTs are found to possess high conductivity with 95% SWNTs demonstrating on/off ratios lower than 100 in transistors. More importantly, it is further demonstrated that this method can be used to directly synthesize dense SWNT networks on transparent substrates which can be utilized as transparent conductive films (TCFs) with very high transparency. Such TCFs can be applied to fabricate a light modulating window as a proof-of-concept. The present work provides important insights into the growth mechanism of SWNTs and great potential for the preparation of TCFs with high scalability, easy operation and low cost.Selective synthesis of single-walled carbon nanotubes (SWNTs) with controlled properties is an important research topic for SWNT studies. Here we report a thiophene-assisted chemical vapor deposition (CVD) method to directly grow highly conductive SWNT thin films on substrates, including transparent ones. By adding low concentration thiophene into the carbon feedstock (ethanol), the as-prepared carbon nanotubes demonstrate an obvious up-shift in the diameter distribution while the single-walled structure is still retained. In the proposed mechanism, the change in the diameter is sourced from the increase in the carbon yield induced by the sulfur-containing compound. Such SWNTs are found to

  1. Surface morphological and photoelectrochemical studies of ZnS thin films developed from single source precursors by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Zinc sulphide (ZnS) thin films have been deposited on fluorine-doped tin oxide-coated conducting glass substrates at 375, 425 and 475 °C temperatures from single source adduct precursors [Zn(S2CNCy2)2(py)] (1) [where, Cy = cyclohexyl, py = pyridine] and [Zn{S2CN(CH2Ph)(Me)}2(py)] (2) [where, Ph = Phenyl, Me = Methyl] using aerosol assisted chemical vapour deposition (AACVD). The precursor complexes have been characterized by microanalysis, infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray single crystal and thermogravimetric analysis. Thermal analysis showed that both precursors (1) and (2) undergo thermal decomposition at 375 °C to produce ZnS residues. The deposited ZnS films have been characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. Scanning electron microscopic studies indicated that the surface morphology of ZnS films strongly depends on the nature of the precursor and the deposition temperature, regardless of marginal variation in thermal stability of the precursors. Direct band gap energies of 3.36 and 3.40 eV have been estimated from the ultraviolet–visible spectroscopy for the ZnS films fabricated from precursors (1) and (2), respectively. The current–voltage characteristics recorded under air mass 1.5 illumination confirmed that the deposited ZnS thin films are photoactive under anodic bias conditions. Furthermore, the photoelectrochemical (PEC) results indicate that these synthesised single source precursors are suitable for obtaining ZnS thin films by AACVD method. The ZnS thin film electrode prepared in this study are very promising for solar energy conversion and optoelectronic applications. The PEC properties of ZnS electrodes prepared from (2) are superior to that of the ZnS electrode prepared from precursor (1). - Highlights: • Synthesis and characterization of zinc dithiocarbamate pyridine adducts. • ZnS photo electrodes have been fabricated using aerosol-assisted chemical vapor

  2. Task 38 - commercial mercury remediation demonstrations: Thermal retorting and physical separation/chemical leaching. Topical report, December 1, 1994--June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, D.S.; Fraley, R.H.; Stepan, D.J.

    1998-12-31

    Results are presented on the demonstration of two commercial technologies for the removal of mercury from soils found at natural gas metering sites. Technologies include a thermal retorting process and a combination of separation, leaching, and electrokinetic separation process.

  3. 牛蒡子化学成分的分离与鉴定%Separation and Identification of Chemical Constituents of Arctium lappa

    Institute of Scientific and Technical Information of China (English)

    李卓恒; 于彩平; 管海燕; 卢来春

    2012-01-01

    目的:分离与鉴定牛蒡子中的化学成分.方法:采用硅胶柱色谱、Sephadex LH-20等手段对牛蒡子进行分离纯化,通过理化性质鉴别与各种波谱学方法鉴定其结构.结果:从牛蒡子中分离鉴定出10个化学成分,分别为β-谷甾醇(1)、牛蒡子苷元(2)、罗汉松脂素(3)、牛蒡酚B(4)、牛蒡酚A(5)、牛蒡酚F(6)、牛蒡子苷(7)、8-hydroxypinoresinol (8)、(+)-Fraxiresinol(9)、胡萝卜苷(10).其中,化合物8、9为首次从牛蒡子中获得.结论:本试验结果可为牛蒡子的进一步研究提供依据.%OBJECTIVE: To separate and identify chemical constituents in the seeds of Arctium lappa. METHODS: Compounds were isolated with silica gel and Sephadex LH-20 gel column chromatography, and its structures were identified on the basis of physiochemical property and spectral analysis. RESULTS: 10 compounds were isolated and identified as β-sitosterol (1), arc tigenin (2), matairesinol (3), lappaol B (4), lappaol A (5), lappaol F (6), arctiin (7), 8-hydroxypinoresinol (8), ( + )-Frax iresinol (9) and daucosterol (10). Compound 8, 9 were obtained form the seeds of A. Lappa for the first time. CONCLUSION: The study provides reference for further study of A. Lappa.

  4. Effects of precursor evaporation temperature on the properties of the yttrium oxide thin films deposited by microwave electron cyclotron resonance plasma assisted metal organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Yttrium oxide thin films are deposited using indigenously developed metal organic precursor (2,2,6,6-tetra methyl-3,5-hepitane dionate) yttrium, commonly known as Y(thd)3 (synthesized by ultrasound method). Microwave electron cyclotron resonance plasma assisted metal organic chemical vapor deposition process was used for these depositions. Depositions were carried out at a substrate temperature of 350 oC with argon to oxygen gas flow rates fixed to 1 sccm and 10 sccm respectively throughout the experiments. The precursor evaporation temperature (precursor temperature) was varied over a range of 170-275 oC keeping all other parameters constant. The deposited coatings are characterized by X-ray photoelectron spectroscopy, glancing angle X-ray diffraction and infrared spectroscopy. Thickness and refractive index of the coatings are measured by the spectroscopic ellipsometry. Hardness and elastic modulus of the films are measured by load depth sensing nanoindentation technique. C-Y2O3 phase is deposited at lower precursor temperature (170 oC). At higher temperature (220 oC) cubic yttrium oxide is deposited with yttrium hydroxide carbonate as a minor phase. When the temperature of the precursor increased (275 oC) further, hexagonal Y2O3 with some multiphase structure including body centered cubic yttria and yttrium silicate is observed in the deposited film. The properties of the films drastically change with these structural transitions. These changes in the film properties are correlated here with the precursor evaporation characteristics obtained at low pressures.

  5. Effect of doping on the Structural and Optical Properties of SnO2 Thin Films fabricated by Aerosol Assisted Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    In order to achieve high conductivity and transmittance of transparent conducting oxide (TCO), we attempted to fabricate Mg doped SnO2 (MgxSn1−xO2) thin films and characterized them for their structural and optical properties. The MgxSn1−xO2 thin films have been deposited on glass substrate by using aero-sole assisted chemical vapor deposition (AACVD). The molar concentration of Mg concentration was changed from 0 to 8%. The confirmation of tetragonal structure and particle size (32 to 87nm) has been calculated of thin films by XRD. The surface roughness is decreased with the increase of the dopant concentration, which has been investigated by atomic force microscopy (AFM). The optical transmission has increased from 54 to 78% and the band gape of pure SnO2 has been found to be in the range of 3.76eV and it is shifted to 3.69eV for 6Wt % Mg doping and then increase on further increasing the Mg doping.

  6. Heterocyclic dithiocarbamato-iron(III) complexes: single-source precursors for aerosol-assisted chemical vapour deposition (AACVD) of iron sulfide thin films.

    Science.gov (United States)

    Mlowe, Sixberth; Lewis, David J; Malik, Mohammad Azad; Raftery, James; Mubofu, Egid B; O'Brien, Paul; Revaprasadu, Neerish

    2016-02-14

    Tris-(piperidinedithiocarbamato)iron(III) (1) and tris-(tetrahydroquinolinedithiocarbamato)iron(iii) (2) complexes have been synthesized and their single-crystal X-ray structures were determined. Thermogravimetric analysis (TGA) of the complexes showed decomposition to iron sulfide. Both complexes were then used as single-source precursors for the deposition of iron sulfide thin films by aerosol-assisted chemical vapour deposition (AACVD). Energy-dispersive X-ray (EDX) spectroscopy confirmed the formation of iron sulfide films. The addition of tert-butyl thiol almost doubled the sulfur content in the deposited films. Scanning electron microscopy (SEM) images of the iron sulfide films from both complexes showed flakes/leaves/sheets, spherical granules and nanofibres. The sizes and shapes of these crystallites depended on the nature of the precursor, temperature, solvent and the amount of tert-butyl thiol used. The observed optical properties are dependent upon the variation of reaction parameters such as temperature and solvent. Powder X-ray diffraction (p-XRD) studies revealed that pyrrhotite, hexagonal (Fe0.975S), marcasite and smythite (Fe3S4) phases were differently deposited. PMID:26732865

  7. Growth of thick La2Zr2O7 buffer layers for coated conductors by polymer-assisted chemical solution deposition

    Science.gov (United States)

    Zhang, Xin; Zhao, Yong; Xia, Yudong; Guo, Chunsheng; Cheng, C. H.; Zhang, Yong; Zhang, Han

    2015-06-01

    La2Zr2O7 (LZO) epitaxial films have been deposited on LaAlO3 (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa2Cu3O7-x (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm2 at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors.

  8. Sub-micron period grating structures in Ta2O5 thin oxide films patterned using UV laser post-exposure chemically assisted selective etching

    International Nuclear Information System (INIS)

    A high-resolution and low-damage method for patterning relief structures in thin Ta2O5 films by chemically assisted UV laser selective etching is presented. The method is based on the initial exposure of the Ta2O5 films to pulsed UV radiation (quadrupled Nd:YAG laser at 266 nm) at fluences below the ablation threshold, for the creation of volume damage in the exposed areas. Subsequent immersion of the exposed sample in a KOH solution results in selective etching of the UV-exposed areas, developing relief structures of high quality. Interferometric exposure was used for the patterning of such gratings with periods of the order of 500 nm in films with a thickness of 100 and 500 nm. The behaviour of the patterning process is studied using diffraction efficiency measurements and AFM scans. Diffraction efficiency increases by a factor of ∼63, compared to the undeveloped structure, were obtained for gratings exposed with 1000 pulses of 30 mJ/cm2 energy density, which were developed in a KOH solution. The etching method presented is being applied to the fabrication of gratings in optical waveguides

  9. Ordered silicon nanowire arrays prepared by an improved nanospheres self-assembly in combination with Ag-assisted wet chemical etching

    Science.gov (United States)

    Jia, Guobin; Westphalen, Jasper; Drexler, Jan; Plentz, Jonathan; Dellith, Jan; Dellith, Andrea; Andrä, Gudrun; Falk, Fritz

    2016-04-01

    An improved Langmuir-Blodgett self-assembly process combined with Ag-assisted wet chemical etching for the preparation of ordered silicon nanowire arrays is presented in this paper. The new process is independent of the surface conditions (hydrophilic or hydrophobic) of the substrate, allowing for depositing a monolayer of closely packed polystyrene nanospheres onto any flat surface. A full control of the morphology of the silicon nanowire is achieved. Furthermore, it is observed that the formation of porous-Si at the tips of the nanowires is closely related to the release of Ag nanoparticles from the Ag mask during the etching, which subsequently redeposit on the surface initially free of Ag, and these Ag nanoparticles catalyze the etching of the tips and lead to the porous-Si formation. This finding will help to improve the resulting nano- and microstructures to get them free of pores, and renders it a promising technology for low-cost high throughput fabrication of specific optical devices, photonic crystals, sensors, MEMS, and NEMS by substituting the costly BOSCH process. It is shown that ordered nanowire arrays free of porous structures can be produced if all sources of Ag nanoparticles are excluded, and structures with aspect ratio more than 100 can be produced.

  10. On the influence of DC electric fields on the aerosol assisted chemical vapor deposition growth of photoactive titanium dioxide thin films.

    Science.gov (United States)

    Romero, Luz; Binions, Russell

    2013-11-01

    Titanium dioxide thin films were deposited on fluorine doped tin oxide glass substrate from the electric field assisted aerosol chemical vapor deposition (EACVD) reaction of titanium isopropoxide (TTIP, Ti(OC3H7)4) in toluene on glass substrates at a temperature of 450 °C. DC electric fields were generated by applying a potential difference between the electrodes of the transparent coated oxide coated glass substrates during the deposition. The deposited films were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and UV-vis spectroscopy. The photoactivity and hydrophilicity of the deposited films were also analyzed using a dye-ink test and water-contact angle measurements. The characterization work revealed that the incorporation of DC electric fields produced significant reproducible changes in the film microstructure, preferred crystallographic orientation, roughness, and film thickness. Photocatalytic activity was calculated from the half-time (t1/2) or time taken to degrade 50% of the initial resazurin dye concentration. A large improvement in photocatalytic activity was observed for films deposited using an electric field with a strong orientation in the (004) direction (t1/2 17 min) as compared to a film deposited with no electric field (t1/2 40 min). PMID:24160408

  11. Growth of thick La2Zr2O7 buffer layers for coated conductors by polymer-assisted chemical solution deposition

    International Nuclear Information System (INIS)

    Highlights: • We develops a low-cost and high-efficient technology of fabricating LZO buffer layers. • Sufficient thickness LZO buffer layers have been obtained on NiW (2 0 0) alloy substrate. • Highly biaxially textured YBCO thin film has been deposited on LZO/NiW. - Abstract: La2Zr2O7 (LZO) epitaxial films have been deposited on LaAlO3 (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa2Cu3O7−x (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm2 at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors

  12. Chemical characteristics of different parts of Coreopsis tinctoria in China using microwave-assisted extraction and high-performance liquid chromatography followed by chemometric analysis.

    Science.gov (United States)

    Lam, Shing-Chung; Liu, Xin; Chen, Xian-Qiang; Hu, De-Jun; Zhao, Jing; Long, Ze-Rong; Fan, Bing; Li, Shao-Ping

    2016-08-01

    Coreopsis tinctoria, also called "snow chrysanthemum" in China, is a flower tea material that has been reported to possess excellent pharmacological properties such as antioxidant and antidiabetic activities. The chemical characteristics of different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were investigated based on microwave-assisted extraction and the simultaneous determination of 13 major active compounds by high-performance liquid chromatography, including taxifolin-7-O-glucoside, chlorogenic acid, (R/S)-flavanomarein, isocoreopsin, quercetagetin-7-O-glucoside, isookanin, 5,7,3',5'-tetrahydroxyflavanone-7-O-glucoside, marein, 3,5-dicaffeoylquinic acid, coreopsin, okanin, 5,7,3',5'-tetrahydroxyflavanone, and N(1) ,N(5) ,N(10) ,N(14) -tetra-p-coumaroylspermine. Chemometric analysis based on the contents of investigated compounds from 13 samples showed that C. tinctoria and the related flower tea materials, Chrysanthemum morifolium cv "Hangju" and "Gongju," were in different clusters, and different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were obviously different. This study is helpful for the quality control and pharmacological evaluation of different parts from C. tinctoria and its related products. PMID:27291468

  13. Transport properties and microstructure of La0.7Sr0.3MnO3 nanocrystalline thin films grown by polymer-assisted chemical solution deposition

    Institute of Scientific and Technical Information of China (English)

    Min Zhang; Li Lv; Zhantao Wei; Xinsheng Yang; Xin Zhang

    2014-01-01

    Perovskite-based materials can be widely used in the aerospace and transportation field. Perovskite man-ganese oxides La0.7Sr0.3MnO3 (LSMO) thin films were grown on LaAlO3 (100) and Si (100) single crystal sub-strates by the polymer-assisted chemical solution deposi-tion (PACSD) method. Electronic transport behavior, microstructure, and magnetoresistance (MR) of LSMO thin films on different substrates were investigated. The resis-tance of LSMO films fabricated on LaAlO3 substrates is smaller than that on the Si substrates. The magnetic field reduces resistance of LSMO films both on Si and LAO in the wide temperature region, when the insulator-metal transition temperature shifts to higher temperature. The low-field magnetoresistance of LSMO films on Si in low temperature range at 1 T is larger than that of LSMO films on LAO. However, the MR of LSMO film on LAO films at room-temperature is about 5.17%. The thin films are smooth and dense with uniform nanocrystal size grain. These results demonstrate that PACSD is an effective technique for producing high quality LSMO films, which is significant to improve the magnetic properties and the application of automotive sensor.

  14. Mass Separation by Metamaterials

    Science.gov (United States)

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2016-02-01

    Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices.

  15. Development of method to chemical separation of gallium-67 by thermal diffusion technique; Desenvolvimento de metodo para separacao quimica de galio-67 pela tecnica de difusao termica

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Patricia de Andrade

    2012-07-01

    Radioisotopes of gallium have been studied and evaluated for medical applications since 1949. Over the past 50 years {sup 67}Ga has been widely used in the diagnosis of various diseases, including acute and chronic inflammatory lesions, bacterial or sterile and several types of tumors. In Brazil 30% of clinics that provide services for Nuclear Medicine use {sup 67}Ga citrate and the demand for 67{sup G}a at IPEN-CNEN/SP is 37 GBq (1 Ci)/week. The {sup 67}Ga presents physical half-life of 3.26 days (78 hours) and decays 100% by electron capture to stable {sup 67}Zn. Its decay includes the emission of {gamma} rays with energies of 93.3 keV (37%), 184.6 keV (20.4%), 300.2 keV (16.6%) and 888 keV (26%). In the past {sup 67}Ga was produced by the reaction {sup 68}Zn (p, 2n) {sup 67}Ga at IPEN-CNEN/SP. After irradiation, the target was dissolved in concentrated HCl and the solution percolated through a cationic resin DOWEX 50W-X8, 200-400 mesh, conditioned with 10 mol L{sup -1} HCl. Zinc, nickel and copper were eluted in 10 mol L{sup -1} HCl and {sup 67}Ga 3.5 mol L{sup -1} HCl. The final product was obtained as {sup 67}Ga citrate. This work presents a new, fast, direct and efficient method for the chemical separation of 67{sup G}a by thermal diffusion (heating of the target) combined with concentrated acetic acid extraction. Purification was performed by ion exchange chromatography. Natural zinc electrodeposition was performed on nickel/copper plates as substrate and the zinc deposits were adherent to the substrate, slightly shiny and uniform. The targets were irradiated with 26 MeV protons and integrated current of 10 {mu}A.h. After irradiation, the targets were heated at 300 deg C for 2 hours and placed in contact with concentrated acetic acid for 1 hour. The average yield of extraction of {sup 67}Ga was (72 {+-} 10)%. This solution was evaporated and the residue was taken up in 0.5 mol L{sup -1} NH{sub 4}OH. The 67{sup G}a was purified on cationic resin Dowex 50WX8

  16. Ionic Liquid-Based Ultrasonic-Assisted Extraction of Forsythosides from the Leaf of Forsythia suspensa (Thunb.) Vahl and Subsequent Separation and Purification by High-Speed Counter-Current Chromatography.

    Science.gov (United States)

    Sun, Yinshi; Hou, Zhiguang; Liu, Zhengbo; Wang, Jianhua

    2016-09-01

    An ionic liquid-based ultrasonic-assisted extraction (ILUAE) method was developed for the extraction of the two forsythosides, namely forsythosides I and A from the leaf of Forsythia suspensa (Thunb.) Vahl. Three kinds of l-alkyl-3-methylimidazolium ionic liquids with different alkyl chain and anion were investigated. The results indicated that ionic liquids showed remarkable effects on the extraction yields of forsythosides. In addition, several ILUAE ultrasonic parameters, such as the solvent concentration, solvent to solid ratio and extraction time have been optimized. Under these optimal conditions (e.g., with 0.6 M [C6MIM]Br, solvent to solid ratio of 15 mL/g and extraction time of 10 min), this approach gained the highest extraction yields of forsythoside I (0.89%) and forsythoside A (10.74%). Meanwhile, forsythosides in the ILUAE extract were separated and purified successfully through the high-speed counter-current chromatography with a two-phase solvent system consisting of ethyl acetate-ethanol-acetic acid-water (4 : 1 : 0.25 : 6, v/v). 5.4 mg of forsythoside I and 59.7 mg of forsythoside A were obtained from 120 mg of the prepurified sample in one-step separation, with the purity of 96.1 and 97.9%, respectively, as determined by high-performance liquid chromatography. Their structures were identified by (1)H nuclear magnetic resonance (NMR) and (13)C NMR. PMID:27165571

  17. Application of alkyl polyglycoside surfactant in ultrasonic-assisted extraction followed by macroporous resin enrichment for the separation of vitexin-2″-O-rhamnoside and vitexin from Crataegus pinnatifida leaves.

    Science.gov (United States)

    Han, Feng; Guo, Yupin; Gu, Huiyan; Li, Fenglan; Hu, Baozhong; Yang, Lei

    2016-02-15

    An alkyl polyglycoside (APG) surfactant was used in ultrasonic-assisted extraction to effectively extract vitexin-2″-O-rhamnoside (VOR) and vitexin (VIT) from Crataegus pinnatifida leaves. APG0810 was selected as the surfactant. The extraction process was optimized for ultrasonic power, the APG concentration, ultrasonic time, soaking time, and liquid-solid ratio. The proposed approach showed good recovery (99.80-102.50% for VOR and 98.83-103.19% for VIT) and reproducibility (relative standard deviation, n=5; 3.7% for VOR and 4.2% for VIT) for both components. The proposed sample preparation method is both simple and effective. The use of APG for extraction of key herbal ingredients shows great potential. Ten widely used commercial macroporous resins were evaluated in a screening study to identify a suitable resin for the separation and purification of VOR and VIT. After comparing static and dynamic adsorption and desorption processes, HPD100B was selected as the most suitable resin. After column adsorption and desorption on this resin, the target compounds VOR and VIT can be effectively separated from the APG0810 extraction solution. Recoveries of VOR and VIT were 89.27%±0.42% and 85.29%±0.36%, respectively. The purity of VOR increased from 35.0% to 58.3% and the purity of VIT increased from 12.5% to 19.9%. PMID:26807707

  18. Preparation of highly photocatalytic active CdS/TiO2 nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    International Nuclear Information System (INIS)

    CdS/TiO2 nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption–desorption measurements. The results show that the CdS/TiO2 nanocomposites were composed of anatase TiO2 and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO2 (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO2 nanocomposites. The CdS/TiO2 (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO2 nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO2 nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO2 changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO2 was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of microwave increased. • Compared with TiO2, as-samples show

  19. Preparation of highly photocatalytic active CdS/TiO{sub 2} nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: qqhrll@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Key Laboratory of Composite Modified Material of Colleges in Heilongjiang Province, Qiqihar 161006 (China); Wang, Lili [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Hu, Tianyu [College of Environment and Resources, Jilin University, Changchun 130024 (China); Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2014-10-15

    CdS/TiO{sub 2} nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N{sub 2} adsorption–desorption measurements. The results show that the CdS/TiO{sub 2} nanocomposites were composed of anatase TiO{sub 2} and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO{sub 2} (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO{sub 2} nanocomposites. The CdS/TiO{sub 2} (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO{sub 2} nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO{sub 2} nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO{sub 2} changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO{sub 2} was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of

  20. A Synergistic Combination of Advanced Separation and Chemical Scale Inhibitor Technologies for Efficient Use of Imparied Water As Cooling Water in Coal-based Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jasbir Gill

    2010-08-30

    Nalco Company is partnering with Argonne National Laboratory (ANL) in this project to jointly develop advanced scale control technologies that will provide cost-effective solutions for coal-based power plants to operate recirculating cooling water systems at high cycles using impaired waters. The overall approach is to use combinations of novel membrane separations and scale inhibitor technologies that will work synergistically, with membrane separations reducing the scaling potential of the cooling water and scale inhibitors extending the safe operating range of the cooling water system. The project started on March 31, 2006 and ended in August 30, 2010. The project was a multiyear, multi-phase project with laboratory research and development as well as a small pilot-scale field demonstration. In Phase 1 (Technical Targets and Proof of Concept), the objectives were to establish quantitative technical targets and develop calcite and silica scale inhibitor chemistries for high stress conditions. Additional Phase I work included bench-scale testing to determine the feasibility of two membrane separation technologies (electrodialysis ED and electrode-ionization EDI) for scale minimization. In Phase 2 (Technology Development and Integration), the objectives were to develop additional novel scale inhibitor chemistries, develop selected separation processes, and optimize the integration of the technology components at the laboratory scale. Phase 3 (Technology Validation) validated the integrated system's performance with a pilot-scale demonstration. During Phase 1, Initial evaluations of impaired water characteristics focused on produced waters and reclaimed municipal wastewater effluents. Literature and new data were collected and evaluated. Characteristics of produced waters vary significantly from one site to another, whereas reclaimed municipal wastewater effluents have relatively more uniform characteristics. Assessment to date confirmed that calcite and silica

  1. A DLVO model for catalyst motion in metal-assisted chemical etching based upon controlled out-of-plane rotational etching and force-displacement measurements

    Science.gov (United States)

    Hildreth, Owen J.; Rykaczewski, Konrad; Fedorov, Andrei G.; Wong, Ching P.

    2013-01-01

    Metal-assisted Chemical Etching of silicon has recently emerged as a powerful technique to fabricate 1D, 2D, and 3D nanostructures in silicon with high feature fidelity. This work demonstrates that out-of-plane rotational catalysts utilizing polymer pinning structures can be designed with excellent control over rotation angle. A plastic deformation model was developed establishing that the catalyst is driven into the silicon substrate with a minimum pressure differential across the catalyst thickness of 0.4-0.6 MPa. Force-displacement curves were gathered between an Au tip and Si or SiO2 substrates under acidic conditions to show that Derjaguin and Landau, Verwey and Overbeek (DLVO) based forces are capable of providing restorative forces on the order of 0.2-0.3 nN with a calculated 11-18 MPa pressure differential across the catalyst. This work illustrates that out-of-plane rotational structures can be designed with controllable rotation and also suggests a new model for the driving force for catalyst motion based on DLVO theory. This process enables the facile fabrication of vertically aligned thin-film metallic structures and scalloped nanostructures in silicon for applications in 3D micro/nano-electromechanical systems, photonic devices, nanofluidics, etc.Metal-assisted Chemical Etching of silicon has recently emerged as a powerful technique to fabricate 1D, 2D, and 3D nanostructures in silicon with high feature fidelity. This work demonstrates that out-of-plane rotational catalysts utilizing polymer pinning structures can be designed with excellent control over rotation angle. A plastic deformation model was developed establishing that the catalyst is driven into the silicon substrate with a minimum pressure differential across the catalyst thickness of 0.4-0.6 MPa. Force-displacement curves were gathered between an Au tip and Si or SiO2 substrates under acidic conditions to show that Derjaguin and Landau, Verwey and Overbeek (DLVO) based forces are capable of

  2. Nanodots and microwires of ZrO2 grown on LaAlO3 by photo-assisted metal-organic chemical vapor deposition

    Science.gov (United States)

    Feng, Guo; Xin-Sheng, Wang; Shi-Wei, Zhuang; Guo-Xing, Li; Bao-Lin, Zhang; Pen-Chu, Chou

    2016-02-01

    ZrO2 nanodots are successfully prepared on LaAlO3 (LAO) (100) substrates by photo-assisted metal-organic chemical vapor deposition (MOCVD). It is indicated that the sizes and densities of ZrO2 nanodots are controllable by modulating the growth temperature, oxygen partial pressure, and growth time. Meanwhile, the microwires are observed on the surfaces of substrates. It is found that there is an obvious competitive relationship between the nanodots and the microwires. In a growth temperature range from 500 °C to 660 °C, the microwires turn longest and widest at 600 °C, but in contrast, the nanodots grow into the smallest diameter at 600 °C. This phenomenon could be illustrated by the energy barrier, decomposition rate of Zr(tmhd)4, and mobility of atoms. In addition, growth time or oxygen partial pressure also affects the competitive relationship between the nanodots and the microwires. With increasing oxygen partial pressure from 451 Pa to 752 Pa, the microwires gradually grow larger while the nanodots become smaller. To further achieve the controllable growth, the coarsening effect of ZrO2 is modified by varying the growth time, and the experimental results show that the coarsening effect of microwires is higher than that of nanodots by increasing the growth time to quickly minimize ZrO2 energy density. Project supported by the National Natural Science Foundation of China (Grant No. 51002063) and the International Science and Technology Cooperation Program of Science and Technology Bureau of Changchun City, China (Grant No. 12ZX68).

  3. Friction and Wear Properties of Selected Solid Lubricating Films. Part 3; Magnetron-Sputtered and Plasma-Assisted, Chemical-Vapor-Deposited Diamondlike Carbon Films

    Science.gov (United States)

    Miyoshi, Kazuhisa; Iwaki, Masanori; Gotoh, Kenichi; Obara, Shingo; Imagawa, Kichiro

    2000-01-01

    To evaluate commercially developed dry solid film lubricants for aerospace bearing applications, an investigation was conducted to examine the friction and wear behavior of magnetron-sputtered diamondlike carbon (MS DLC) and plasma-assisted, chemical-vapor-deposited diamondlike carbon (PACVD DLC) films in sliding contact with 6-mm-diameter American Iron and Steel Institute (AISI) 440C stainless steel balls. Unidirectional sliding friction experiments were conducted with a load of 5.9 N (600 g), a mean Hertzian contact pressure of 0.79 GPa (maximum Hertzian contact pressure of L-2 GPa), and a sliding velocity of 0.2 m/s. The experiments were conducted at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7x10(exp -7) Pa), humid air (relative humidity, approx.20 percent), and dry nitrogen (relative humidity, films were characterized by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and surface profilometry. Marked differences in the friction and wear of the DLC films investigated herein resulted from the environmental conditions. The main criteria for judging the performance of the DLC films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cu mm/N-m or less, respectively. MS DLC films and PACVD DLC films met the criteria in humid air and dry nitrogen but failed in ultrahigh vacuum, where the coefficients of friction were greater than the criterion, 0.3. In sliding contact with 440C stainless steel balls in all three environments the PACVD DLC films exhibited better tribological performance (i.e., lower friction and wear) than the MS DLC films. All sliding involved adhesive transfer of wear materials: transfer of DLC wear debris to the counterpart 440C stainless steel and transfer of 440C stainless steel wear debris to the counterpart DLC film.

  4. Growth of thick La{sub 2}Zr{sub 2}O{sub 7} buffer layers for coated conductors by polymer-assisted chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin, E-mail: xzhang@my.swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Yong, E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Xia, Yudong [State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Guo, Chunsheng [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Zhang, Yong [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, Han [Department of Physics, Peking University, Beijing 100871 (China)

    2015-06-15

    Highlights: • We develops a low-cost and high-efficient technology of fabricating LZO buffer layers. • Sufficient thickness LZO buffer layers have been obtained on NiW (2 0 0) alloy substrate. • Highly biaxially textured YBCO thin film has been deposited on LZO/NiW. - Abstract: La{sub 2}Zr{sub 2}O{sub 7} (LZO) epitaxial films have been deposited on LaAlO{sub 3} (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa{sub 2}Cu{sub 3}O{sub 7−x} (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm{sup 2} at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors.

  5. Autocatalytic chemical smoke rings

    CERN Document Server

    Rogers, M C; Rogers, Michael C.; Morris, Stephen W.

    2005-01-01

    Buoyant plumes, evolving free of boundary constraints, may develop well-defined mushroom shaped heads. In normal plumes, overturning flow in the head entrains less buoyant fluid from the surroundings as the head rises, robbing the plume of its driving force. We consider here a new type of plume in which the source of buoyancy is an autocatalytic chemical reaction. The reaction occurs at a sharp front which separates reactants from less dense products. In this type of plume, entrainment assists the reaction, producing new buoyancy which fuels an accelerating plume head. When the head has grown to a critical size, it detaches from the upwelling conduit, forming an accelerating, buoyant vortex ring. This vortex is analogous to a rising smoke ring. A second-generation head then develops at the point of detachment.Multiple generations of chemical vortex rings can detach from a single triggering event.

  6. Ultracapacitor separator

    Science.gov (United States)

    Wei, Chang; Jerabek, Elihu Calvin; LeBlanc, Jr., Oliver Harris

    2001-03-06

    An ultracapacitor includes two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. The electrolyte is a polar aprotic organic solvent and a salt. The porous separator comprises a wet laid cellulosic material.

  7. Simultaneous and selective decarboxylation of L-serine and deamination of L-phenylalanine in an amino acid mixture--a means of separating amino acids for synthesizing biobased chemicals.

    Science.gov (United States)

    Teng, Yinglai; Scott, Elinor L; Witte-van Dijk, Susan C M; Sanders, Johan P M

    2016-01-25

    Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. PMID:25976628

  8. Teaching Separations: Why, What, When, and How?

    Science.gov (United States)

    Wankat, Phillip C.

    2001-01-01

    Describes how and when to teach separation science to chemical engineering students. Separation science is important for industrial businesses involving the manufacture of adsorption systems, distillation columns, extractors, and other separation equipment and techniques. (Contains 13 references.) (YDS)

  9. Laser isotope separation techniques

    International Nuclear Information System (INIS)

    Having examined the high cost and low efficiency of existing processes for separating uranium isotopes in comparison with the encouraging assessed figures for laser separation processes and having considered the high potential separation factors which make possibly very low 235U concentrations in the depleted tailings from laser separation processes, the design of such a system is considered. There are two essential features. Firstly, only one isotope must absorb laser radiation, and secondly that absorption must lead to a successful physical or chemical separation of that species which has been optically excited. Such a scheme is illustrated and discussed. The important aspect of loss mechanisms which can depopulate the selectively excited levels and the ways in which isotopes may exhibit differences in optical absorption frequencies are considered. Examples are given to illustrate techniques used in the separation stage. Finally a summary is presented of those elements in which some enrichment has been achieved by optical techniques. (U.K.)

  10. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

  11. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    International Nuclear Information System (INIS)

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO2 film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MOx/ZnO nanorod core–shell structures, where MOx was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO2 as anatase. For the multi-layered shell sample, the existence of Fe2O3 as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition, materials absorptance determined from

  12. The Cryo-Thermochromatographic Separator (CTS) A new rapid separation and alpha-detection system for on-line chemical studies of highly volatile osmium and hassium (Z=108) tetroxides

    CERN Document Server

    Kirbach, U W; Gregorich, K E; Lee, D M; Ninov, V; Omtvedt, J P; Patin, J B; Seward, N K; Strellis, D A; Sudowe, R; Türler, A; Wilk, P A; Zielinski, P M; Hoffman, D C; Nitsche, H

    2002-01-01

    The Cryo-Thermochromatographic Separator (CTS) was designed and constructed for rapid, continuous on-line separation and simultaneous detection of highly volatile compounds of short-lived alpha-decaying isotopes of osmium and hassium (Hs, Z=108). A flowing carrier gas containing the volatile species is passed through a channel formed by two facing rows of 32 alpha-particle detectors, cooled to form a temperature gradient extending from 247 K at the channel entrance down to 176 K at the exit. The volatile species adsorb onto the SiO sub 2 -coated detector surfaces at a characteristic deposition temperature and are identified by their observed alpha-decay energies. The CTS was tested on-line with OsO sub 4 prepared from sup 1 sup 6 sup 9 sup - sup 1 sup 7 sup 3 Os isotopes produced in sup 1 sup 1 sup 8 sup , sup 1 sup 2 sup 0 Sn( sup 5 sup 6 Fe, 3,4,5n) reactions. An adsorption enthalpy for OsO sub 4 of -40.2+-1.5 kJ/mol on SiO sub 2 was deduced by comparing the measured deposition distribution with Monte Carlo...

  13. Dielectrophoretic separation of gaseous isotopes

    International Nuclear Information System (INIS)

    This invention relates to a process for the separation of gaseous isotopes by electrophoresis assisted by convective countercurrent flow and to an apparatus for use in the process. The invention is especially applicable to heavy water separation from steam; however, it is to be understood that the invention is broadly applicable to the separation of gaseous isotopes having different dipole moments and/or different molecular weights. (author)

  14. Temperature-induced phase separation and hydration in poly(N-vinylcaprolactam) aqueous solutions: a study by NMR and IR spectroscopy, SAXS, and quantum-chemical calculations

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Dybal, Jiří; Starovoytova, Larisa; Zhigunov, Alexander; Sedláková, Zdeňka

    2012-01-01

    Roč. 8, č. 22 (2012), s. 6110-6119. ISSN 1744-683X R&D Projects: GA ČR GA202/09/1281 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : phase separation * coil-globule phase transition * aqueous solution Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.909, year: 2012

  15. Metals separation using solvent extractants on magnetic microparticles

    International Nuclear Information System (INIS)

    The magnetically assisted chemical separation program was initially funded by DOE EM-50 to develop processes for the efficient separation of radionuclides and other hazardous metals. This process has simulated the partnership between industry and ANL for many applications related to hazardous metal problems in industry. In-tank or near-tank hazardous metals separation using magnetic particles promises simple, compact processing at very low costs and employs mature chemical separations technologies to remove and recover hazardous metals from aqueous solutions. The selective chemical extractants are attached to inexpensive magnetic carrier particles. Surfaces of small particles composed of rare earths or ferromagnetic materials are treated to retain chemical extractants (e.g., TBP, CMPO, quaternary amines, carboxylic acid). After selective partitioning of contaminants to the surface layer, magnets are used to collect the loaded particles from the tank. The particles can be regenerated by stripping the contaminants and the selective metals can be recovered and recycled from the strip solution. This process and its related equipment are simple enough to be used for recovery/recycling and waste minimization activities at many industrial sites. Both the development of the process for hazardous and radioactive waste and the transfer of the technology will be discussed

  16. Separation of uranium isotopes

    International Nuclear Information System (INIS)

    This invention provides a method for separating uranium isotopes comprising the steps of selectively irradiating a photochemically-reactive uranyl source material at a wavelength selective to a desired isotope of uranium at an effective temperature for isotope spectral line splitting below about 77 K, further irradiating the source material within the fluorescent lifetime of the selectively irradiated source material to selectively photochemically reduce the selectively excited isotopic species, and chemically separating the reduced isotope species from the remaining uranyl salt compound

  17. The Use of Atmospheric Pressure Chemical Ionization Mass Spectrometry with High Performance Liquid Chromatography and Other Separation Techniques for Identification of Triacylglycerols

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Sigler, Karel

    2007-01-01

    Roč. 3, - (2007), s. 252-271. ISSN 1573-4110 R&D Projects: GA ČR GA203/06/0219 Institutional research plan: CEZ:AV0Z50200510 Keywords : triacylglycerols * atmospheric presssure chemical ionization * mass spectrometry Subject RIV: EE - Microbiology, Virology Impact factor: 1.815, year: 2007

  18. A study on chemical separation of 55Fe, 59Ni, 63Ni, 90Sr and 94Nb in boric acid matrix

    International Nuclear Information System (INIS)

    Several radionuclides are considered as an object of the assesment to develop a scaling factor and a periodical verification method which are needed for the evaluation of radionuclide inventory of concentration bottoms from nuclear power plants in Korea. A selective separation of 55Fe, 59Ni, 63Ni, 90Sr and 94Nb which should be recovered individually for the radioactivity measurement was described in detail. Sorption and desorption behaviours of ion exchange and extraction chromatographic resins for Fe, Ni, Sr, Nb and co-existing metal ions in boric acid matrix were investigated using simulated concentration bottom dissolved solutions. Separation conditions available for the sequential recovery of the metal ions from a single sample were optimized to minimize a discharge of radioactive wastes produced through the analytical process and the radiation exposure to analysts. Their recovery yields were measured with reliability

  19. Deuterium isotope separation

    International Nuclear Information System (INIS)

    Deuterium-containing molecules are separated and enriched by exposing commercially available ethylene, vinyl chloride, 1,2-dichloroethane or propylene to the radiation of tuned infrared lasers to selectively decompose these compounds into enriched molecular products containing deuterium atoms. The deuterium containing molecules can be easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. (author)

  20. Combination of chemical separation and data treatment for {sup 55}Fe, {sup 63}Ni, {sup 99}Tc, {sup 137}Cs and {sup 90}Sr/{sup 90}Y activity determination in radioactive waste by liquid scintillation

    Energy Technology Data Exchange (ETDEWEB)

    Mellado, J. [Departament de Quimica Analitica, Facultat de Quimica, Universitat de Barcelona, C/Marti Franques 1, 08028 Barcelona (Spain); Tarancon, A. [Departament de Quimica Analitica, Facultat de Quimica, Universitat de Barcelona, C/Marti Franques 1, 08028 Barcelona (Spain); Garcia, J.F. [Departament de Pintura, Facultat de Belles Arts, Universitat de Barcelona, C/Pau Gargallo 4, 08028 Barcelona (Spain)]. E-mail: jfgarcia@apolo.qui.ub.es; Rauret, G. [Departament de Quimica Analitica, Facultat de Quimica, Universitat de Barcelona, C/Marti Franques 1, 08028 Barcelona (Spain); Warwick, P. [Geoscience Advisory Unit, Southampton Oceanography Centre, Southampton SO14 3ZH (United Kingdom)

    2005-08-01

    Routine operations involving nuclear reactors and decommissioning activities require numerous chemical analyses. Most of the procedures developed for these chemical characterisations involve several separation steps to prepare the sample for measurement. Chemical treatments are time- and manpower-consuming, labour intensive and produce significant quantities of waste. In order to address this problem, we evaluate a data treatment procedure (multivariate calibration-PLS), which we propose as a substitute to some of these separation steps. Mixtures of beta emitter radionuclides of increasing complexity ({sup 90}Sr/{sup 90}Y-{sup 99}Tc, {sup 90}Sr/{sup 90}Y-{sup 99}Tc-{sup 63}Ni-{sup 137}Cs and {sup 90}Sr/{sup 90}Y-{sup 99}Tc-{sup 63}Ni-{sup 137}Cs-{sup 55}Fe) have been measured by liquid scintillation (LS) counting. The influences of quenching and level of activity was evaluated and the activity of unknown samples determined. Despite the spectra overlapping and low resolution of LS, relative errors in the activities quantification of unknown samples inside the range covered by the calibration matrix are lower than 15% whatever the number of radionuclides included in the solution was.

  1. Combination of chemical separation and data treatment for 55Fe, 63Ni, 99Tc, 137Cs and 90Sr/90Y activity determination in radioactive waste by liquid scintillation

    International Nuclear Information System (INIS)

    Routine operations involving nuclear reactors and decommissioning activities require numerous chemical analyses. Most of the procedures developed for these chemical characterisations involve several separation steps to prepare the sample for measurement. Chemical treatments are time- and manpower-consuming, labour intensive and produce significant quantities of waste. In order to address this problem, we evaluate a data treatment procedure (multivariate calibration-PLS), which we propose as a substitute to some of these separation steps. Mixtures of beta emitter radionuclides of increasing complexity (90Sr/90Y-99Tc, 90Sr/90Y-99Tc-63Ni-137Cs and 90Sr/90Y-99Tc-63Ni-137Cs-55Fe) have been measured by liquid scintillation (LS) counting. The influences of quenching and level of activity was evaluated and the activity of unknown samples determined. Despite the spectra overlapping and low resolution of LS, relative errors in the activities quantification of unknown samples inside the range covered by the calibration matrix are lower than 15% whatever the number of radionuclides included in the solution was

  2. Near-infrared spectra of Penicillium camemberti strains separated by extended multiplicative signal correction improved prediction of physical and chemical variations

    DEFF Research Database (Denmark)

    Decker, Marianne; Nielsen, Per Væggemose; Martens, Harald

    2005-01-01

    signal correction (TWEMSC) preprocessing, whereby three patterns of variation in near-infrared (NIR) log(1/R) spectra of fungal colonies could be separated mathematically: (1) physical light scattering and its wavelength dependency, (2) differences in light absorption of water due to varying sample...... temperature, etc., and (3) differences in light absorption between different fungal isolates. With this preprocessing, discriminant partial least squares (PLS) regression yielded 100% correct classification of three isolates, both within the cross-validated calibration set and in two independent test sets of...

  3. High-Jc YBa2Cu3O7−δ superconducting film grown by laser-assisted chemical vapor deposition using a single liquid source and its microstructure

    International Nuclear Information System (INIS)

    A YBa2Cu3O7-δ (YBCO) film was prepared on a multilayer-coated Hastelloy C276 substrate by laser-assisted metalorganic chemical vapor deposition using a single liquid source precursor. A c-axis-oriented YBCO film was grown epitaxially on a (100) CeO2 layer at a deposition rate of 11 μm h−1. A screw dislocation and stacking faults were observed in the cross-section of the YBCO film. The critical current density of the YBCO film reached 2.7 MA cm−2. (paper)

  4. Electrostatically Enhanced Vortex Separator

    Science.gov (United States)

    Collins, Earl R.

    1993-01-01

    Proposed device removes fine particles from high-pressure exhaust gas of chemical reactor. Negatively charged sectors on rotating disks in vortex generator attracts positively charged particles from main stream of exhaust gas. Electrostatic charge enhances particle-separating action of vortex. Gas without particles released to atmosphere.

  5. Surgical Assisting

    Science.gov (United States)

    ... specific training over and above a degree in science, nursing, physician assisting, or another health profession. Prerequisites . Recommended eligibility requirements for admission into a surgical assisting program are: Bachelor of Science degree (or higher) Associate degree in an allied ...

  6. Assistive Technology

    Science.gov (United States)

    ... Page Resize Text Printer Friendly Online Chat Assistive Technology Assistive technology (AT) is any service or tool that helps ... be difficult or impossible. For older adults, such technology may be a walker to improve mobility or ...

  7. Assisted Living

    Science.gov (United States)

    ... overwhelming majority of residents are female. Assisted Living Philosophy The philosophy of assisted living is to provide personalized, resident ... loved ones to learn about the care provider philosophy . Freedom of Choice The most progressive state regulations ...

  8. Experimental study on thermal chemical separation of cesium by melting from municipal solid waste incineration ash, sewage sludge incineration ash and soil

    International Nuclear Information System (INIS)

    Due to the occurrence of the Great East Japan Earthquake, large amount of radioactive cesium (Cs) diffused around the Fukushima area, and the treatment of solids to which Cs was transferred has become a pressing issue. Melting technology can volatilize alkali metals and heavy metals with the addition of chlorides or combustibles by reduction or chlorination reaction and separate those metals into molten fly ash. Because Cs is also a kind of alkali metal element, it is thought to be capable of separation by a similar mechanism. So, in this study, for the purpose of investigating the volatilization characteristics of Cs, laboratory melting test was performed for municipal waste incineration ash, sewage sludge incineration ash and soil doped with non-radioactive Cs. When CaCl2 was added as a chloride, volatilization of alkali metals and heavy metals was promoted for all kinds of solids, so CaCl2 was found to have Cs volatilization promoting effect. Alkali metal element which had larger atomic number got higher volatilization rate. The higher the basicity of molten slag was, the higher volatilization rate was. When activated carbon was added as a combustible, volatilization of heavy metals was promoted, but that of alkali metals was not promoted. However, by the co-addition with CaCl2, activated carbon expressed volatilization promoting effect also for the alkali metals, and Cs volatilization rate of more than 99% was obtained. Further, when PVC waste was added as a volatilization promoter, because it contained both chlorides and combustibles, volatilization of alkali metals and heavy metals was promoted to the same extent as in the case of CaCl2 addition, so PVC waste was found to have sufficient Cs volatilization promoting effect. (author)

  9. Task Group report to the Assistant Secretary for Environment, Safety and Health on oversight of chemical safety at the Department of Energy. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    This report presents the results of a preliminary review of chemical safety within the Department of Energy (DOE). The review was conducted by Chemical Safety Oversight Review (CSOR) Teams composed of Office of Environment, Safety and Health (EH) staff members and contractors. The primary objective of the CSOR was to assess, the safety status of DOE chemical operations and identify any significant deficiencies associated with such operations. Significant was defined as any situation posing unacceptable risk, that is, imminent danger or threat to workers, co-located workers, the general public, or the environment, that requires prompt action by EH or the line organizations. A secondary objective of the CSOR was to gather and analyze technical and programmatic information related to chemical safety to be used in conjunction with the longer-range EH Workplace Chemical Accident Risk Review (WCARR) Program. The WCARR Program is part of the ongoing EH oversight of nonnuclear safety at all DOE facilities. `` The program objective is to analyze DOE and industry chemical safety programs and performance and determine the need for additional or improved safety guidance for DOE. During the period June 6, 1992, through July 31, 1992, EH conducted CSORs at five DOE sites. The sites visited were Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 Plant (Y-12), Oak Ridge National Laboratory (ORNL), and Lawrence Livermore National Laboratory (LLNL).

  10. Synthesis and characterization of silicon carbonitride films by plasma enhanced chemical vapor deposition (PECVD) using bis(dimethylamino)dimethylsilane (BDMADMS), as membrane for a small molecule gas separation

    Science.gov (United States)

    Kafrouni, W.; Rouessac, V.; Julbe, A.; Durand, J.

    2010-12-01

    Silicon carbonitride thin films have been deposited by plasma enhanced chemical vapor deposition (PECVD) from bis(dimethylamino)dimethylsilane (BDMADMS) as a function of X = (BDMADMS/(BDMADMS + NH 3)) between 0.1 and 1, and plasma power P (W) between 100 and 400 W. The microstructure of obtained materials has been studied by SEM, FTIR, EDS, ellipsometrie, and contact angle of water measurements. The structure of the materials is strongly depended on plasma parameters; we can pass from a material rich in carbon to a material rich in nitrogen. Single gas permeation tests have been carried out and we have obtained a helium permeance of about 10 -7 mol m -2 s -1 Pa -1 and ideal selectivity of helium over nitrogen of about 20.

  11. Chemical modification of silica gel with synthesized Schiff base hydrazone derivative and application for preconcentration and separation of U(VI) ions from aqueous solutions

    International Nuclear Information System (INIS)

    Schiff base hydrazone derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of U(VI) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, Schiff base hydrazone derivative (HL) was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane, then analyzed by Fourier transform infrared, Brunauer-Emmett-Teller, scanning electron microscopy and elemental analysis. The influence of the solution pH, amount of sorbent, contact time, temperature, foreign ion effect and initial U(VI) concentration was investigated. The maximum U(VI) uptake capacity was found to be 8.46 mg/g. (author)

  12. Separations chemistry

    International Nuclear Information System (INIS)

    Results of studies on the photochemistry of aqueous Pu solutions and the stability of iodine in liquid and gaseous CO2 are reported. Progress is reported in studies on: the preparation of macroporous bodies filled with oxides and sulfides to be used as adsorbents; the beneficiation of photographic wastes; the anion exchange adsorption of transition elements from thiosulfate solutions; advanced filtration applications of energy significance; high-resolution separations; and, the examination of the separation agents, octylphenylphosphoric acid (OPPA) and trihexyl phosphate (THP)

  13. Product separator

    Science.gov (United States)

    Welsh, Robert A.; Deurbrouck, Albert W.

    1976-01-20

    A secondary light sensitive photoelectric product separator for use with a primary product separator that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate separation is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to separate from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted nothing moves on the second separator. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected separated concentrate is recovered at a maximum rate regardless of variations in the flow stream or other conditions present.

  14. Expeditious method to determine uranium in the process control samples of chemical plant separating (233)U from thoria irradiated in power reactors.

    Science.gov (United States)

    Kedari, C S; Kharwandikar, B K; Banerjee, K

    2016-11-01

    Analysis of U in the samples containing a significant proportion of (232)U and high concentration of Th is of great concern. Transmutation of Th in the nuclear power reactor produces a notable quantity of (232)U (half life 68.9 years) along with fissile isotope (233)U. The decay series of (232)U is initiated with (228)Th (half life 1.9 year) and it is followed by several short lived α emitting progenies, (224)Ra, (220)Rn, (216)Po, (212)Bi and (212)Po. Even at the smallest contamination of (228)Th in the sample, a very high pulse rate of α emission is obtained, which is to be counted for the radiometric determination of [U]. A commercially available anionic type of extractant Alamine®336 is used to obtain the selective extraction of U from other alpha active elements and fission products present in the sample. Experimental conditions of liquid-liquid extraction (LLE) are optimized for obtaining maximum decontamination and recovery of U in the organic phase. The effect of some interfering ionic impurities in the sample on the process of separation is investigated. Depending on the level of the concentration of U in the samples, spectrophotometry or radiometry methods are adopted for its determination after separation by LLE. Under optimized experimental conditions, i.e. 5.5M HCl in the aqueous phase and 0.27M Alamin®336 in the organic phase, the recovery of U is about 100%, the decontamination factor with respect to Th is >2000 and the extraction of fission products like (90)Sr, (144)Ce and (134,137)Cs is negligible. The detection limit for [U] using α radiometry is 10mg/L, even in presence of >100g/L of Th in the sample. Accuracy and precision for the determination of U is also assessed. Reproducibility of results is within 5%. This method shows very good agreement with the results obtained by mass spectrometry. PMID:27591623

  15. Theoretical and Experimental Study of the Magnetic Separation of Pollutants from Wastewater

    OpenAIRE

    Mariani, Giacomo

    2010-01-01

    This Thesys reports the study of a HGMS (High GradientMagnetic Separation) process for the treatment of industrialwastewaters that considers an assisted chemical-physical pre-treatment for the removal of heavy metals through the bound by adsorption with added iron-oxide particulate matter (hematite). The considered filter, constituted by ferromagnetic stainless steel wool and permanent magnets, is studied with a new approach based on a statistical analysis that requires the study of the traje...

  16. Design and morphology control of polymer nanocomposites using light-driven phase separation phenomena

    International Nuclear Information System (INIS)

    Phase separation of polymer mixtures is induced and controlled by photo-cross-link and photopolymerization using ultraviolet (UV) light. By taking advantage of the competition between phase separation and chemical reactions, a variety of morphologies such as co-continuous, spatially graded co-continuous and periodic structures with controllable periods, and hexagonal structures, etc, are obtained experimentally. The reaction kinetics (photo-cross-link or photopolymerization), reaction-induced elastic strain and phase separation kinetics are monitored, respectively, by UV–Vis spectroscopy, FTIR, Mach–Zehnder interferometry (MZI), light scattering (LS) and laser-scanning confocal microscopy (LSCM). Spatial modulation of light intensity generated by computer-assisted irradiation (CAI) is also used to induce phase separation of polymer blends. The correlation between the reaction-induced phase separation of polymer mixtures and the competing interactions is discussed with some perspectives on designing polymer materials with high performance. (review)

  17. Separation and structural identification on chemical constituent In Arctium Lappa L.%牛蒡子化学成分的分离及结构鉴定

    Institute of Scientific and Technical Information of China (English)

    赵杨; 李虹; 张文治

    2013-01-01

    the chemical consituents of fructus and bracts were researched. The compounds were obtained by various chromatographic meheods silica gel and their structures were elucidated on the basis of physical parameters and spectral data including NMR and MS. Five compounds were determined as Arctigenin, lappaol B, Matairesinol, 8,10,12-eighteen-carbon three olefine acid,β-sitosterol.%  利用硅胶柱和HPLC等色谱方法对黑龙江省绥化市兰西县的牛蒡子进行研究,经理化性质和波谱分析数据进行结构鉴定,得到5个单体化合物,分别鉴定为:牛蒡苷元、邻苯二甲酸二异丁酯、罗汉松脂素、8,10,12-十八碳三烯酸、B-谷甾醇。

  18. The production of fuels and chemicals from food processing wastes using a novel fermenter separator. Annual progress report, January 1991--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Dale, M.C.; Venkatesh, K.V.; Choi, Hojoon; Moelhman, M.; Saliceti, L.; Okos, M.R.; Wankat, P.C.

    1991-12-01

    During 1991, considerable progress was made on the waste utilization project. Two small Wisconsin companies have expressed an interest in promoting and developing the ICRS technology. Pilot plant sites at (1) Hopkinton, IA, for a sweet whey plant, and Beaver Dam WI, for an acid whey site have been under development siting ICRS operations. The Hopkinton, IA site is owned and operated by Permeate Refining Inc., who have built a batch ethanol plant across the street from Swiss Valley Farms cheddar cheese operations. Permeate from Swiss Valley is piped across to PRI. PRI has signed a contract to site a 300--500,000 gallon/yr to ICRS pilot plant. They feel that the lower labor, lower energy, continuous process offered by the ICRS will substantially improve their profitability. Catalytics, Inc, is involved with converting whey from a Kraft cream cheese operation to ethanol and yeast. A complete project including whey concentration, sterilization, and yeast growth has been designed for this site. Process design improvements with the ICRS focussed on ethanol recovery techniques during this year`s project. A solvent absorption/extractive distillation (SAED) process has been developed which offers the capability of obtaining an anhydrous ethanol product from vapors off 3 to 9% ethanol solutions using very little energy for distillation. Work on products from waste streams was also performed. a. Diacetyl as a high value flavor compound was very successfully produced in a Stirred Tank Reactor w/Separation. b. Yeast production from secondary carbohydrates in the whey, lactic acid, and glycerol was studied. c. Lactic acid production from cellulose and lactose studies continued. d. Production of anti-fungal reagents by immobilized plant cells; Gossypol has antifungal properties and is produced by G. arboretum.

  19. Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

    OpenAIRE

    Thandavan, Tamil Many K.; Gani, Siti Meriam Abdul; San Wong, Chiow; Md. Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as ...

  20. Azadirachta indica plant-assisted green synthesis of Mn3O4 nanoparticles: Excellent thermal catalytic performance and chemical sensing behavior.

    Science.gov (United States)

    Sharma, Jitendra Kumar; Srivastava, Pratibha; Ameen, Sadia; Akhtar, M Shaheer; Singh, Gurdip; Yadava, Sudha

    2016-06-15

    The leaf extract of Azadirachta indica (Neem) plant was utilized as reducing agent for the green synthesis of Mn3O4 nanoparticles (NPs). The crystalline analysis demonstrated the typical tetragonal hausmannite crystal structure of Mn3O4, which confirmed the formation of Mn3O4 NPs without the existence of other oxides. Green synthesized Mn3O4 NPs were applied for the catalytic thermal decomposition of ammonium perchlorate (AP) and as working electrode for fabricating the chemical sensor. The excellent catalytic effect for the thermal decomposition of AP was observed by decreasing the decomposition temperature by 175°C with single decomposing step. The fabricated chemical sensor based on green synthesized Mn3O4 NPs displayed high, reliable and reproducible sensitivity of ∼569.2μAmM(-1)cm(-2) with reasonable limit of detection (LOD) of ∼22.1μM and the response time of ∼10s toward the detection of 2-butanone chemical. A relatively good linearity in the ranging from ∼20 to 160μM was detected for Mn3O4 NPs electrode based 2-butanone chemical sensor. PMID:27038784

  1. Vision 2020: 2000 Separations Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Stephen [Center for Waster Reduction Technologies; Beaver, Earl [Practical Sustainability; Bryan, Paul [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Robinson, Sharon [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watson, Jack [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2000-01-01

    This report documents the results of four workshops on the technology barriers, research needs, and priorities of the chemical, agricultural, petroleum, and pharmaceutical industries as they relate to separation technologies utilizing adsorbents, crystallization, distillation, extraction, membranes, separative reactors, ion exchange, bioseparations, and dilute solutions.

  2. Separator material for electrochemical cells

    Science.gov (United States)

    Cieslak, Wendy R.; Storz, Leonard J.

    1991-01-01

    An electrochemical cell characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant.

  3. Informed source separation: source coding meets source separation

    OpenAIRE

    Ozerov, Alexey; Liutkus, Antoine; Badeau, Roland; Richard, Gaël

    2011-01-01

    We consider the informed source separation (ISS) problem where, given the sources and the mixtures, any kind of side-information can be computed during a so-called encoding stage. This side-information is then used to assist source separation, given the mixtures only, at the so-called decoding stage. State of the art ISS approaches do not really consider ISS as a coding problem and rely on some purely source separation-inspired strategies, leading to performances that can at best reach those ...

  4. Lithium isotope separation

    International Nuclear Information System (INIS)

    Published methods for 6Li-7Li lithium isotope separation have been reviewed. Future demand for 6Li, whose main use will be as a tritium breeder in blankets surrounding the core of DT fusion power reactors, is likely to exceed 5 Mg/a in the next century. The applicability of the various available methods to such a large scale production rate has been assessed. Research on improving the effectiveness of current lithium isotope separation processes has been carried out worldwide in several major areas during the past decade; these include two-phase chemical exchange systems, ion exchange resin chromatography, highly isotope-selective techniques like laser photoactivation and radiofrequency spectroscopy. Chemical exchange systems appear to offer good potential in the near term for 6Li enrichment

  5. Theoretical modeling of temperature dependent catalyst-assisted growth of conical carbon nanotube tip by plasma enhanced chemical vapor deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, Aarti; Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University (DTU), Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India)

    2015-02-15

    A theoretical model has been developed to examine the effect of substrate temperature on the growth of the conical carbon nanotube (CNT) tip assisted by the catalyst in a reactive plasma. The growth rate of the CNT with conical tip because of diffusion and accretion of ions on catalyst nanoparticle including the charging rate of the CNT, kinetics of plasma species, and the evolution of the substrate temperature in reactive plasma has been taken into account. The effect of substrate temperature for different ion densities and temperatures on the growth of the conical CNT tip has been investigated for typical glow discharge plasma parameters. The results of the present model can serve as a major tool in better understanding of plasma heating effects on the growth of CNTs.

  6. Composite separators and redox flow batteries based on porous separators

    Science.gov (United States)

    Li, Bin; Wei, Xiaoliang; Luo, Qingtao; Nie, Zimin; Wang, Wei; Sprenkle, Vincent L.

    2016-01-12

    Composite separators having a porous structure and including acid-stable, hydrophilic, inorganic particles enmeshed in a substantially fully fluorinated polyolefin matrix can be utilized in a number of applications. The inorganic particles can provide hydrophilic characteristics. The pores of the separator result in good selectivity and electrical conductivity. The fluorinated polymeric backbone can result in high chemical stability. Accordingly, one application of the composite separators is in redox flow batteries as low cost membranes. In such applications, the composite separator can also enable additional property-enhancing features compared to ion-exchange membranes. For example, simple capacity control can be achieved through hydraulic pressure by balancing the volumes of electrolyte on each side of the separator. While a porous separator can also allow for volume and pressure regulation, in RFBs that utilize corrosive and/or oxidizing compounds, the composite separators described herein are preferable for their robustness in the presence of such compounds.

  7. Surface molecular imprinting onto fluorescein-coated magnetic nanoparticlesvia reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals

    Science.gov (United States)

    Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

    2011-01-01

    In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic

  8. Efficient separations & processing crosscutting program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The Efficient Separations and Processing Crosscutting Program (ESP) was created in 1991 to identify, develop, and perfect chemical and physical separations technologies and chemical processes which treat wastes and address environmental problems throughout the DOE complex. The ESP funds several multiyear tasks that address high-priority waste remediation problems involving high-level, low-level, transuranic, hazardous, and mixed (radioactive and hazardous) wastes. The ESP supports applied research and development (R & D) leading to the demonstration or use of these separations technologies by other organizations within the Department of Energy (DOE), Office of Environmental Management.

  9. Separation of W from Ta, Hf, Lu and Mo by BPHA-C5H11OH/HCl extraction system (Model experiments for chemical study of seaborgium, the 106th element)

    International Nuclear Information System (INIS)

    In the batch experiment with W, Ta, Hf, Lu and Mo as radiotracers, a new rapid radiochemical isolation procedure for element tungsten has been developed by using radiochemical separation method and γ spectrum measurement technique. With Voltalef powder carried 2% (W/V) BPHA (Benzoyl-phenyl-hydroxyl-amine)-C5H11OH (iso-amyl-alcohol) organic solution, radioactive W was adsorbed on the Voltalef column in the 4 mol/L hydrochloric acid system. Hf, Lu and Mo fractions passed through the Voltalef column rapidly and partial Ta activities retained on the Voltalef column, respectively. Following this, W fraction was eluted completely with 1%Na3C6H5O7 (sodium citrate)-5%(W/V) NH4OH solution and no Hf, Lu, Ta and Mo activities passed through the Voltalef extraction chromatographic column. The procedure was simultaneously used to isolate W from Er target bombarded with a low energy 12C beams. By means of this separation system, it is one of the possible way to develop an isolation procedure of Sg, supposing the chemical property of Sg is similar to that of tungsten

  10. GPS Separator

    CERN Multimedia

    2016-01-01

    Footage of the 70 degree ISOLDE GPS separator magnet MAG70 as well as the switchyard for the Central Mass and GLM (GPS Low Mass) and GHM (GPS High Mass) beamlines in the GPS separator zone. In the GPS20 vacuum sector equipment such as the long GPS scanner 482 / 483 unit, faraday cup FC 490, vacuum valves and wiregrid piston WG210 and WG475 and radiation monitors can also be seen. Also the RILIS laser guidance and trajectory can be seen, the GPS main beamgate switch box and the actual GLM, GHM and Central Beamline beamgates in the beamlines as well as the first electrostatic quadrupoles for the GPS lines. Close up of the GHM deflector plates motor and connections and the inspection glass at the GHM side of the switchyard.

  11. HRS Separator

    CERN Multimedia

    2016-01-01

    Footage of the 90 and 60 degree ISOLDE HRS separator magnets in the HRS separator zone. In the two vacuum sectors HRS20 and HRS30 equipment such as the HRS slits SL240, the HRS faraday cup FC300 and wiregrid WG210 can be spotted. Vacuum valves, turbo pumps, beamlines, quadrupoles, water and compressed air connections, DC and signal cabling can be seen throughout the video. The HRS main and user beamgate in the beamline between MAG90 and MAG60 and its switchboxes as well as all vacuum bellows and flanges are shown. Instrumentation such as the HRS scanner unit 482 / 483, the HRS WG470 wiregrid and slits piston can be seen. The different quadrupoles and supports are shown as well as the RILIS guidance tubes and installation at the magnets and the different radiation monitors.

  12. Significant improvements of the high-field properties of carbon-doped MgB2 films by hot-filament-assisted hybrid physical-chemical vapor deposition using methane as the doping source

    International Nuclear Information System (INIS)

    We report a significant enhancement in upper critical field Hc2 and irreversibility field Hirr in carbon-doped MgB2 films fabricated by hot-filament-assisted hybrid physical-chemical vapor deposition (HFA-HPCVD) using methane as the doping source. For the parallel field, a very large temperature derivative -dHc2parallelab/dT value of 3 T K-1 near Tc was achieved in a heavily doped film with Tc near 28 K. Carbon doping also enhanced flux pinning, resulting in a much higher critical current density in a magnetic field Jc(H) than in undoped samples. The result suggests a more effective doping of carbon into the MgB2 structure and a better connectivity between the carbon-doped MgB2 grains than in previous reports. A clear correlation between the decrease in grain size and the enhancement of Hc2 was observed. (rapid communication)

  13. Component Separations

    OpenAIRE

    Heller, Lior; McNichols, Colton H.; Ramirez, Oscar M.

    2012-01-01

    Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-...

  14. Component separations.

    Science.gov (United States)

    Heller, Lior; McNichols, Colton H; Ramirez, Oscar M

    2012-02-01

    Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options. PMID:23372455

  15. Design and fabrication of a computer-controlled rapid-isothermal-processing-assisted metalorganic chemical-vapor-deposition system for high-temperature superconducting thin films and related materials

    International Nuclear Information System (INIS)

    Metalorganic chemical vapor deposition (MOCVD) is an ideal technique for the development of several high-temperature superconducting products. For the development of certain electronic products, reduced thermal budget (product of processing time and temperature) processing is a necessity. Rapid isothermal processing (RIP) based on incoherent light as the source of energy is emerging as a key reduced thermal budget processing technique. Driven by potential applications a RIP-assisted MOCVD system has been designed and fabricated for the deposition of high-temperature superconducting thin films and related materials. Experimental details of the RIP-assisted MOCVD system are described. The results of Y-Ba-Cu-O (YBCO) films deposited on yttrium-stabilized zirconia, SrTiO3, and MgO substrates are also presented. In the case of SrTiO3 substrates, YBCO films were deposited at a substrate temperature of 640 degree C. The onset temperature is 91 K and the transition temperature Tc is observed at 89 K. The value of zero-magnetic-field current density Jc at 77 K is 1.5x106 A/cm2. The results presented represent the best values of transition temperature Tc, c-axis orientation, and zero magnetic-field critical current density Jc values for the thermal budget used in the growth of the superconducting thin films by MOCVD

  16. Screw-Dislocation-Driven Growth of Two-Dimensional Few-Layer and Pyramid-Like WSe2 by Sulfur-Assisted Chemical Vapor Deposition

    OpenAIRE

    Chen, Liang; Liu, Bilu; Abbas, Ahmad N.; Ma, Yuqiang; Fang, Xin; Liu, Yihang; Zhou, Chongwu

    2014-01-01

    Two-dimensional (2D) layered tungsten diselenides (WSe2) material has recently drawn a lot of attention due to its unique optoelectronic properties and ambipolar transport behavior. However, direct chemical vapor deposition (CVD) synthesis of 2D WSe2 is not as straightforward as other 2D materials due to the low reactivity between reactants in WSe2 synthesis. In addition, the growth mechanism of WSe2 in such CVD process remains unclear. Here we report the observation of a screw-dislocation-dr...

  17. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    Directory of Open Access Journals (Sweden)

    Tamil Many K Thandavan

    Full Text Available Vapor phase transport (VPT assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn was used to prepare un-doped and Al-doped zinc oxide (ZnO nanostructures (NSs. The structure and morphology were characterized by field emission scanning electron microscopy (FESEM and x-ray diffraction (XRD. Photoluminescence (PL properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni, oxygen interstitials (Oi, zinc vacancy (Vzn, singly charged zinc vacancy (VZn-, oxygen vacancy (Vo, singly charged oxygen vacancy (Vo+ and oxygen anti-site defects (OZn in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

  18. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    Science.gov (United States)

    Thandavan, Tamil Many K; Gani, Siti Meriam Abdul; San Wong, Chiow; Md Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs. PMID:25756598

  19. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    International Nuclear Information System (INIS)

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100–260 Torr pressure range and 1.5–2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (ηcoup) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance

  20. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    Science.gov (United States)

    Nad, Shreya; Gu, Yajun; Asmussen, Jes

    2015-07-01

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100-260 Torr pressure range and 1.5-2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (ηcoup) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.

  1. Fixation of laccase enzyme into polypyrrole, assisted by chemical interaction with modified magnetite nanoparticles: A facile route to synthesize stable electroactive bionanocomposite catalysts

    International Nuclear Information System (INIS)

    Highlights: • Chemically immobilized laccase enzyme on magnetite nanoparticles is presented. • Modified nanoparticles were entrapped in conducting polymer matrix. • Bio-electrocatalytic effect was evidenced in the oxygen reduction reaction. • The method may serve as a general platform for enzyme incorporation. • New avenue for conducting polymer based biocatalytic electrodes. - Abstract: Effective bio-electrocatalysts require stable immobilization of sufficient amounts of the bioactive component. In this study, a novel and efficient method for specific binding of laccase enzyme onto magnetite nanoparticles (NPs) is presented. The interaction between the chemically modified magnetite NPs and the enzyme was evidenced by both infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). Subsequently, the enzyme-coated magnetite NPs were successfully incorporated into polypyrrole (PPy) matrix during galvanostatic electropolymerization. The encapsulation of laccase covered NPs was proved by EQCN, TEM, and FT-IR spectroscopy; whereas the electrochemical behaviour of the formed bionanocomposite was characterized by cyclic voltammetry. In oxygen saturated solution a cathodic charge surplus was observed, related to the electrochemical reduction of oxygen. This surplus was two times higher in the case of the laccase containing layer compared to its only magnetite containing counterpart. Kinetic aspects of the oxygen reduction reaction (ORR) on the laccase containing films were investigated by hydrodynamic voltammetry, and the four-electron route was found to be exclusive, which is promising from the fuel cell perspective. Such synergistic combination of inorganic NPs and enzymes may open new avenues in the application of these bio-nanocomposite materials

  2. Children Who Won't Go to School (Separation Anxiety)

    Science.gov (United States)

    ... separation anxiety disorder. The potential long-term effects (anxiety and panic disorder as an adult) are serious for a child who has persistent separation anxiety and does not receive professional assistance. The child ...

  3. Magnetic separator

    OpenAIRE

    Křupka, Jiří

    2015-01-01

    Cílem bakalářské práce je návrh konstrukčního řešení magnetického separátoru určeného k separaci drobného průmyslového odpadu. Tato zpráva obsahuje přehled zařízení světových výrobců, která slouží k magnetické separaci ocelového odpadu. Dále pak posouzení variant technických řešení konstrukčních uzlů magnetického separátoru a následný výběr konkrétního řešení. Dle vstupních parametrů jsou vypočteny všechny parametry potřebné ke správnému návrhu stroje. Ve výpočtech jsou zahrnuty i odůvodnění ...

  4. Synthesis of TBP-coated magnetic Pst-DVB particles for uranium separation

    International Nuclear Information System (INIS)

    Magnetically assisted chemical separation process is an efficient method used widely in separating radionuclides and heavy metals in environmental samples. It is simple, compact and cost-effective, with less secondary waste streams. Tributyl phosphate (TBP)-coated magnetic poly (styrene-divinylbenzene) (Pst-DVB) nano-particles were synthesized and characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry and Fourier transform infrared spectrometry. The application of TBP-coated magnetic Pst-DVB particles in separating low concentration of uranium from aqueous media was evaluated, and the equilibrium adsorption isotherm was investigated. Our results indicate that the TBP-coated magnetic Pst-DVB particles may be of potential application for uranium separation. (authors)

  5. Assisted Ventilation.

    Science.gov (United States)

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear. PMID:25501776

  6. Room temperature hydrogen gas sensor based on ZnO nanorod arrays grown on a SiO2/Si substrate via a microwave-assisted chemical solution method

    International Nuclear Information System (INIS)

    Highlights: ► Highly quality ZnO nanorods arrays were grown on SiO2 substrate using chemical solution. ► We use PVA–Zn(OH)2 nanocomposites as seed layer to grow ZnO nanorods. ► ZnO nanorods arrays show good sensitivity at room temperature to H2 gas. - Abstract: High-quality zinc oxide (ZnO) nanorod arrays were grown on a silicon dioxide (SiO2/Si) substrate via a microwave irradiation-assisted chemical solution method. The SiO2/Si substrate was seeded with polyvinyl alcohol–Zn (OH)2 nanocomposites prior to the complete growth of ZnO nanorods through a chemical solution method. X-ray diffraction, field-emission scanning electron microscope, and photoluminescence results indicated the high quality of the produced ZnO nanorods. The hydrogen (H2)-sensing capabilities of the ZnO nanorod arrays were investigated at room temperature (RT), and the sensitivity was 294% in the presence of 1000 ppm of H2. The sensing measurements for H2 gas at various temperatures (25–250 °C) were repeatable for over 100 min. The sensor exhibited a sensitivity of 1100% at 250 °C upon exposure to 1000 ppm of H2. Hysteresis was observed in the sensor at different H2 concentrations at different temperatures. Moreover, the response times ranged from 60 to 25 s over the range of operating temperatures from RT to 250 °C.

  7. Room temperature hydrogen gas sensor based on ZnO nanorod arrays grown on a SiO{sub 2}/Si substrate via a microwave-assisted chemical solution method

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, J.J., E-mail: j1j2h72@yahoo.com [Nano-Optoelectronics Research and Technology Laboratory (N.O.R), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Physics, College of Science, University of Basrah, Basrah (Iraq); Mahdi, M.A. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Physics, College of Science, University of Basrah, Basrah (Iraq); Chin, C.W.; Abu-Hassan, H. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Hassan, Z., E-mail: zai@usm.my [Nano-Optoelectronics Research and Technology Laboratory (N.O.R), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2013-01-05

    Highlights: Black-Right-Pointing-Pointer Highly quality ZnO nanorods arrays were grown on SiO{sub 2} substrate using chemical solution. Black-Right-Pointing-Pointer We use PVA-Zn(OH){sub 2} nanocomposites as seed layer to grow ZnO nanorods. Black-Right-Pointing-Pointer ZnO nanorods arrays show good sensitivity at room temperature to H{sub 2} gas. - Abstract: High-quality zinc oxide (ZnO) nanorod arrays were grown on a silicon dioxide (SiO{sub 2}/Si) substrate via a microwave irradiation-assisted chemical solution method. The SiO{sub 2}/Si substrate was seeded with polyvinyl alcohol-Zn (OH){sub 2} nanocomposites prior to the complete growth of ZnO nanorods through a chemical solution method. X-ray diffraction, field-emission scanning electron microscope, and photoluminescence results indicated the high quality of the produced ZnO nanorods. The hydrogen (H{sub 2})-sensing capabilities of the ZnO nanorod arrays were investigated at room temperature (RT), and the sensitivity was 294% in the presence of 1000 ppm of H{sub 2}. The sensing measurements for H{sub 2} gas at various temperatures (25-250 Degree-Sign C) were repeatable for over 100 min. The sensor exhibited a sensitivity of 1100% at 250 Degree-Sign C upon exposure to 1000 ppm of H{sub 2}. Hysteresis was observed in the sensor at different H{sub 2} concentrations at different temperatures. Moreover, the response times ranged from 60 to 25 s over the range of operating temperatures from RT to 250 Degree-Sign C.

  8. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    International Nuclear Information System (INIS)

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites. (paper)

  9. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    Science.gov (United States)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  10. Effects of N{sub 2}O gas addition on the properties of ZnO films grown by catalytic reaction-assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Kanji, E-mail: kyasui@vos.nagaokaut.ac.jp; Morioka, Makoto; Kanauchi, Shingo; Ohashi, Yuki; Kato, Takahiro; Tamayama, Yasuhiro [Department of Electrical, Electronic, and Information Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

    2015-11-15

    The influence of N{sub 2}O gas addition on the properties of zinc oxide (ZnO) films grown on a-plane (11–20) sapphire (a-Al{sub 2}O{sub 3}) substrates was investigated, using a chemical vapor deposition method based on the reaction between dimethylzinc and high-temperature H{sub 2}O produced by a catalytic H{sub 2}-O{sub 2} reaction on platinum (Pt) nanoparticles. The addition of N{sub 2}O was found to increase the size of the crystalline facets and to improve the crystal orientation along the c-axis. The electron mobility at 290 K was also increased to 234 cm{sup 2}/Vs following the addition of N{sub 2}O gas at a pressure of 3.2 × 10{sup −3 }Pa. In addition, the minimum full width at half maximum of the most intense photoluminescence peak derived from neutral donor bound excitons at 10 K decreased to 0.6 meV by the addition of N{sub 2}O gas at a pressure of 3.1 × 10{sup −2 }Pa.

  11. Weatherization Assistance Program Technical Assistance Center

    Energy Technology Data Exchange (ETDEWEB)

    Robert Adams

    2009-01-07

    The following is a synopsis of the major achievements attributed to the operation of the Weatherization Assistance Program Technical Assistance Center (WAPTAC) by the National Association for State Community Services Programs (NASCSP). During the past five years, the WAPTAC has developed into the premier source for information related to operating the Weatherization Assistance Program (WAP) at the state and local levels. The services provide through WAPTAC include both virtual technical support as well as hands-on training and instruction in classroom and in the field. The WAPTAC achieved several important milestones during its operation including the establishment of a national Weatherization Day now celebrated in most states, the implementation of a comprehensive Public Information Campaign (PIC) to raise the awareness of the Program among policy makers and the public, the training of more than 150 new state managers and staff as they assume their duties in state offices around the country, and the creation and support of a major virtual information source on the Internet being accessed by thousands of staff each month. The Weatherization Assistance Program Technical Assistance Center serves the Department of Energy's (DOE) Office of Weatherization and Intergovernmental Program as a valuable training and technical assistance resource for the network of 54 direct state grantees (50 states, District of Columbia and three Native American tribes) and the network of 900 local subgrantees (comprised of community action agencies, units of local government, and other non-profit organizations). The services provided through WAPTAC focus on standardizing and improving the daily management of the WAP. Staff continually identify policies changes and best practices to help the network improve its effectiveness and enhance the benefits of the Program for the customers who receive service and the federal and private investors. The operations of WAPTAC are separated into

  12. Rapid automated batchwize radiochemical separation techniques

    International Nuclear Information System (INIS)

    The basic principles and specific techniques of rapid, automated radiochemical separation techniques that use batchwize separation methods are reviewed. The basic chemical technics include many standard methods used in analytical chemistry: precipitation, solvent extraction, ion exchange, distillation, volatilization, electrolysis and electrophoresis. Isotopic exchange, absorption and thermochromatography are examples of other techniques specially used in fast separation procedures. Auobatch techniques were used for the automatic process: silver isotope separation, technetium, palladium separation by solvent extraction, arsenic and antimony separation by volatile hydriole production, separation of individual rare earth fission products. (R.P.) 40 refs

  13. 77 FR 57544 - Native American Housing Assistance and Self-Determination Reauthorization Act of 1996: Request...

    Science.gov (United States)

    2012-09-18

    ... Americans. NAHASDA eliminated several separate assistance programs and replaced them with a single block... URBAN DEVELOPMENT 24 CFR Part 1000 Native American Housing Assistance and Self-Determination... Housing Block Grant program authorized by the Native American Housing Assistance and...

  14. Experimental Study on Gas Curtain-assisted High Gradient Magnetic Separation of Iron Tailling%气幕辅助高梯度磁选回收尾矿中铁的试验研究

    Institute of Scientific and Technical Information of China (English)

    王建平; 于克旭

    2012-01-01

    A new type of high gradient magnetic separation was designed in this paper, which has the feature of introducing airflow into the separation region to increase the concentrate grade. This device was adopted for the tailing containing iron. The results indicated that the iron concentrate with the grade of 45.10% and the recovery of 48. 17% was obtained from the raw ore with the iron grade of 17.80% through the process ofcentrifugal separation for primarily removing tailings and one roughing one cleaning high gradient magnetic separation. The grade of the iron concentrate can be improved by the gas curtain attributed to bubble agitation and negative pressure and strong fluctuation produced from bubble crushing. Meanwhile, the bubble can make the mineral particles stay in the separation process, decreasing the grade of tailings.%本文设计了一种新型气幕辅助高梯度磁选模型,其特点是在分选区域引入上升的气泡群以提高精矿品位.利用该设备对含铁尾矿进行选铁试验,结果表明,通过离心选初次抛尾,再经过一粗一精高梯度磁选,可从铁品位为17.80%的原矿中,得到铁品位为45.10%,回收率为48.17%的铁精矿.气幕能提高铁精矿品位归功于气泡的搅拌作用和气泡破碎时形成的负压及强扰动,同时气泡使矿物颗粒在分选区停留时同延长,可降低尾矿品位.

  15. Hearing Assistive Technology

    Science.gov (United States)

    ... for the Public / Hearing and Balance Hearing Assistive Technology Hearing Assistive Technology: FM Systems | Infrared Systems | Induction ... Assistive Technology Systems Solutions What are hearing assistive technology systems (HATS)? Hearing assistive technology systems (HATS) are ...

  16. Comparison of clinical semi-quantitative assessment of muscle fat infiltration with quantitative assessment using chemical shift-based water/fat separation in MR studies of the calf of post-menopausal women

    Energy Technology Data Exchange (ETDEWEB)

    Alizai, Hamza; Nardo, Lorenzo; Karampinos, Dimitrios C.; Joseph, Gabby B.; Yap, Samuel P.; Baum, Thomas; Krug, Roland; Majumdar, Sharmila; Link, Thomas M. [University of California, San Francisco, Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States)

    2012-07-15

    The goal of this study was to compare the semi-quantitative Goutallier classification for fat infiltration with quantitative fat-fraction derived from a magnetic resonance imaging (MRI) chemical shift-based water/fat separation technique. Sixty-two women (age 61 {+-} 6 years), 27 of whom had diabetes, underwent MRI of the calf using a T1-weighted fast spin-echo sequence and a six-echo spoiled gradient-echo sequence at 3 T. Water/fat images and fat fraction maps were reconstructed using the IDEAL algorithm with T2* correction and a multi-peak model for the fat spectrum. Two radiologists scored fat infiltration on the T1-weighted images using the Goutallier classification in six muscle compartments. Spearman correlations between the Goutallier grades and the fat fraction were calculated; in addition, intra-observer and inter-observer agreement were calculated. A significant correlation between the clinical grading and the fat fraction values was found for all muscle compartments (P < 0.0001, R values ranging from 0.79 to 0.88). Goutallier grades 0-4 had a fat fraction ranging from 3.5 to 19%. Intra-observer and inter-observer agreement values of 0.83 and 0.81 were calculated for the semi-quantitative grading. Semi-quantitative grading of intramuscular fat and quantitative fat fraction were significantly correlated and both techniques had excellent reproducibility. However, the clinical grading was found to overestimate muscle fat. (orig.)

  17. Study the Experiment of High Concentration Containing Salt Wastewater Nanofiltration Separation in Coal Chemical Industry%煤化工行业高浓度含盐废水纳滤分离实验探究

    Institute of Scientific and Technical Information of China (English)

    刘燕龙; 杜再娟; 王禹淇

    2014-01-01

    由于反渗透浓水处理技术在国内尚未具有成熟的工程应用,尤其采用纳滤和盐水分离器工艺还未有实质性的工程案例,通过各项中试试验,分析比较系统运行过程中出现的问题,总结经验和方法,为后续的工业化应用提供参考性建议。最终,能够让煤化工行业浓水回用处理,作为循环水补水。%Due to the reverse osmosis concentrated water treatment technology, currently in the country has not yet has the engi-neering application of mature, especially by nanofiltration and water separator process has not been substantial project case, through the test, analysis of problems in the process of system operation, and summarize the experience and method, and provid-ing reference advice for industrial application subsequent. Finally, to make the coal chemical industry concentrated water reuse treatment as make-up water for circulating water.

  18. 基于化学链制氧的 O2/CO2燃烧电站性能分析%Performance analysis of an O2/CO2 power plant based on chemical looping air separation

    Institute of Scientific and Technical Information of China (English)

    顾鹏飞; 向文国

    2015-01-01

    采用 Aspen Plus 软件对基于化学链高温空分制氧技术(CLAS)的 O2/CO2燃烧电厂全过程进行建模,对化学链高温空分单元进行运行参数及功耗分析,并对化学链高温空分单元、锅炉热力发电系统和烟气冷却压缩单元(CCU)进行耦合并优化,确定高温烟气抽取温度及抽取流量.结果表明,O2/CO2燃烧系统的净效率为39.2%,仅比不能进行碳捕集的常规电厂低3.54%.然而,基于深冷空分技术的 O2/CO2燃烧系统会使得全厂净效率下降8%~10%.当采取优化措施后,O2/CO2燃烧系统效率能够提高1.65%.烟气冷却压缩单元能耗占总能耗的59.7%,泵能耗占27.1%.化学链制氧单元的供氧浓度为12.2%.%The process of an O2 /CO2 power plant based on chemical looping air separation (CLAS)is modeled using the Aspen Plus software.The operating parameters and power consumption of the CLAS unit are analyzed.The CLAS system,thermal power generation system and flue gas cooling and compression unit (CCU)are coupled and optimized,and the temperature and flow of the flue gas extraction are determined.The results indicate that the net plant efficiency of CLAS O2 /CO2 power plant is 39.2%,which is only 3.54%lower than that of the conventional power plants without carbon capture.However,the O2 /CO2 power plant based on cryogenic air separation technology brings 8% to 10%decrease in the net plant efficiency.By optimizations,the net plant efficiency increases by 1.65%.The energy consumption of the CCU accounts for 59.7% and the pump accounts for 27.1%.The oxygen concentration from the chemical looping air separation unit is 12.2%.

  19. Measurement and analysis of internal loss and injection efficiency for continuous-wave blue semipolar ( 20 2 ¯ 1 ¯ ) III-nitride laser diodes with chemically assisted ion beam etched facets

    Science.gov (United States)

    Becerra, Daniel L.; Kuritzky, Leah Y.; Nedy, Joseph; Saud Abbas, Arwa; Pourhashemi, Arash; Farrell, Robert M.; Cohen, Daniel A.; DenBaars, Steven P.; Speck, James S.; Nakamura, Shuji

    2016-02-01

    Continuous-wave blue semipolar ( 20 2 ¯ 1 ¯ ) III-nitride laser diodes were fabricated with highly vertical, smooth, and uniform mirror facets produced by chemically assisted ion beam etching. Uniform mirror facets are a requirement for accurate experimental determination of internal laser parameters, including internal loss and injection efficiency, which were determined to be 9 cm-1 and 73%, respectively, using the cavity length dependent method. The cavity length of the uncoated devices was varied from 900 μm to 1800 μm, with threshold current densities ranging from 3 kA/cm2 to 9 kA/cm2 and threshold voltages ranging from 5.5 V to 7 V. The experimentally determined internal loss was found to be in good agreement with a calculated value of 9.5 cm-1 using a 1D mode solver. The loss in each layer was calculated and in light of the analysis several modifications to the laser design are proposed.

  20. Chemical sputtering

    International Nuclear Information System (INIS)

    In this thesis, the author focuses on chemical sputtering by keV ions, treating two specific examples: the chemical effects occurring when bombarding simple condensed gases and the mechanisms of the ion-assisted etching process. First, however, the mechanism of sputtering of condensed gases in general is discussed. These mechanisms have been investigated using condensed noble gases as target material. The thesis is a compilation of articles published elsewhere. Contents: sputtering of condensed noble gases by keV heavy ions; surface distribution as an observable factor in the energy distribution of sputtered particles; reactive sputtering of simple condensed gases by keV heavy ion bombardment; mass spectra of nozzle-produced small molecular clusters of H2O, NH3, CO and CH4; mass and energy distribution of particles sputter-etched from Si in a XeF2 environment; argon-ion assisted etching of silicon by molecular chlorine; energy distribution of sputtered poly-atomic molecules. (Auth.)

  1. Foreign assistance

    International Nuclear Information System (INIS)

    This paper reports that providing energy assistance to developing countries remains a relatively low priority of the Agency for International Development. AID is helping some developing countries meet their energy needs, but this assistance varies substantially because of the agency's decentralized structure. Most AID energy funding has gone to a handful of countries-primarily Egypt and Pakistan. With limited funding in most other countries, AID concentrates on providing technical expertise and promoting energy policy reforms that will encourage both energy efficiency and leverage investment by the private sector and other donors. Although a 1989 congressional directive to pursue a global warming initiative has had a marginal impact on the agency's energy programming, many AID energy programs, including those directed at energy conservation, help address global warming concerns

  2. SEC separation near exclusion limit

    Czech Academy of Sciences Publication Activity Database

    Netopilík, Miloš

    Prague: Organic , Bioorganic and Pharmaceutical Chemistry Branch of the Czech Chemical Society, 2015. s. 120. [Advances in Organic , Bioorganic and Pharmaceutical Chemistry /50./ - "Liblice 2015". 06.11.2015-08.11.2015, Olomouc] R&D Projects: GA ČR(CZ) GA13-02938S Institutional support: RVO:61389013 Keywords : SEC * light scattering * separation Subject RIV: CD - Macromolecular Chemistry

  3. Work control in separations facilities

    International Nuclear Information System (INIS)

    The topic addressed in this technical review is the development and implementation of a work control program in one of the chemical separations facilities at the Savannah River Site (SRS) in Aiken, SC. This program will be used as a pilot for the Nuclear Materials Processing Division at the site. The SRS Work Control Pilot program is based on the Institute of Nuclear Power Operations (INPO) good practices and guidelines for the conduct of maintenance and complies with SRS quality assurance and DOE orders on maintenance management. The program follows a ten-step process for control of maintenance and maintenance-related activities in a chemical separations facility. The program took the existing maintenance planning and scheduling system and upgraded it to comply with all INPO work control and related guidelines for histories, post-maintenance testing and scheduling. The development process of adapting a nuclear-related- based plan to a batch/continuous chemical separations plant was a challenge. There were many opportunities to develop improvements in performance while being creative and realistic in applying reactor maintenance technology to chemical plant maintenance. This pilot program for work control in a nonreactor nuclear facility will provide valuable information for applying a controlled maintenance process to a multiphase chemical operating plant environment

  4. Microwave and RF assisted chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Barbero, R.S. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    Work during this reporting period has focused on the development of a CVI technique for rapid production of carbon/carbon and alumina composite systems. The focus of the alumina effort is towards porous materials for membrane supports and hot gas filtration. Industrial interest in these applications include companies such as: Dow, Westinghouse, Amoco and DuPont. Applications for the carbon materials are numerous and include: brakes, sporting goods, biomedical materials, flaps and seals for thrust control, after burner nozzles, turbine engine flaps and rotors. This effort will focus on aircraft brakes. A collaboration is underway with Hitco a major producer of carbon/carbon materials.

  5. Pseudo-stationary separation materials for highly parallel separations.

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anup K.; Palmer, Christopher (University of Montana, Missoula, MT)

    2005-05-01

    Goal of this study was to develop and characterize novel polymeric materials as pseudostationary phases in electrokinetic chromatography. Fundamental studies have characterized the chromatographic selectivity of the materials as a function of chemical structure and molecular conformation. The selectivities of the polymers has been studied extensively, resulting in a large body of fundamental knowledge regarding the performance and selectivity of polymeric pseudostationary phases. Two polymers have also been used for amino acid and peptide separations, and with laser induced fluorescence detection. The polymers performed well for the separation of derivatized amino acids, and provided some significant differences in selectivity relative to a commonly used micellar pseudostationary phase. The polymers did not perform well for peptide separations. The polymers were compatible with laser induced fluorescence detection, indicating that they should also be compatible with chip-based separations.

  6. Shoulder separation - aftercare

    Science.gov (United States)

    Separated shoulder - aftercare; Acromioclavicular joint separation - aftercare; A/C separation - aftercare ... Shoulder separation is not an injury to the main shoulder joint itself. It is an injury to ...

  7. Separation of metals by supported liquid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Takigawa, D.Y.

    1990-12-31

    A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.

  8. Ultrasound-assisted dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry in negative chemical ionization mode for the determination of polybrominated diphenyl ethers in water.

    Science.gov (United States)

    Zhang, Qian; Liang, Tao; Guan, Lili

    2013-04-01

    A simple and economical method for the determination of eight polybrominated diphenyl ethers (BDE-28, 47, 99, 100,153,154,183, and 209) in water was developed. This method involves the use of ultrasound-assisted dispersive liquid-liquid microextraction combined with GC-MS in negative chemical ionization mode. Various parameters affecting the extraction efficiency, including the type and volume of extraction and dispersive solvents, salt concentration, extraction time, and ultrasonic time, were investigated. A volume of 1.0 mL of acetone (dispersive solvent) containing 10 μL tetrachloroethylene (extraction solvent) was injected into 5.0 mL of water samples and then emulsified by ultrasound for 2.0 min to produce the cloudy solution. Under the optimal condition, the enrichment factors for the eight PBDEs were varied from 845- to 1050-folds. Good linearity was observed in the range of 1.0-200 ng L(-1) for BDE-28, 47, 99, and 100; 5.0-200 ng L(-1) for BDE-153, 154, and 183; and 5.0-500 ng L(-1) for BDE-209. The RSD values were in the range of 2.5-8.4% (n = 5) and the LODs ranged from 0.40 to 2.15 ng L(-1) (S/N = 3). The developed method was applied for the determination of eight BPDEs in the river and lake water samples, and the mean recoveries at spiking levels of 5.0 and 50.0 ng L(-1) were in the range of 70.6-105.1%. PMID:23483741

  9. Optical properties and chemical composition analyses of mixed rare earth oxyorthosilicate (R2SiO5, R=La, Gd and Y) doped Dy3+ phosphors prepared by urea-assisted solution combustion method

    Science.gov (United States)

    Ogugua, S. N.; Shaat, S. K. K.; Swart, H. C.; Ntwaeaborwa, O. M.

    2015-08-01

    Dysprosium (Dy3+) doped lanthanum gadolinium oxyorthosilicate (LaGdSiO5), lanthanum yttrium oxyorthosilicate (LaYSiO5) and gadolinium yttrium oxyorthosilicate (GdYSiO5) phosphors (in powder form) were synthesized by urea-assisted combustion method. The X-ray diffractometer analysis confirmed that the LaGdSiO5, LaYSiO5 and GdYSiO5 crystalized in monoclinic phases. The chemical composition of the phosphors was analyzed by measuring the atomic and molecular ionic species using the time of flight secondary ion mass spectroscopy (ToF SIMS). In addition, ToF SIMS imaging technique was used to determine the distribution of the Dy3+ dopant ions on the surface on the phosphors. The average crystallite sizes and lattice strains of the phosphor were increased by Dy3+ doping. The field emission scanning electron microscope images showed that the powders were made up of an agglomeration of particles with no regular shape. The photoluminescence data showed narrow line emission peaks at the wavelengths of 485 nm (minor emission) and 573 nm (major emission) associated with the f→f transitions of Dy3+. The photoluminescence (PL) measurements showed that the emission peak of LaGdSiO5:Dy3+ was ~3× more intense than those of LaYSiO5:Dy3+ and GdYSiO5:Dy3+ when excited using monochromatic xenon lamp with a wavelength of 241 nm. However, when the powders were excited using a 325 nm He-Cd laser, the highest PL emission intensity was observed from GdYSiO5:Dy3+.

  10. Sticky fix : new technology claims to solve separation problems

    Energy Technology Data Exchange (ETDEWEB)

    Radison, T.

    2008-02-15

    A technology capable of turning a barrel of oilsands into stratified layers of bitumen, sands, and residual materials was presented. The Petromax technology has successfully separated bitumen from sand, and broken up mature fine tailings into layers of heavy metals, water, Petromax solution, and bitumen. The technology was originally designed to remove the sludge from crude oil storage tanks, and has been used to transform viscous sludge into pumpable slurries. The technology uses the zeta potential, which manipulates the ionic charge on the surface of materials through both a physical and chemical process, causing particles that normally attract each other to repel one another. Use of the technology in in situ underground processes without heat has resulted in a 95 per cent yield. The technology has also been in situ process with vertical wells rather than the horizontal wells typically used in steam assisted gravity drainage (SAGD) processes. The process is currently being patented, and pilot plants are being planned. 2 figs.

  11. Ferrofluid separator for nonferrous scrap separation

    Science.gov (United States)

    Kaiser, R.; Mir, L.

    1974-01-01

    Behavior of nonmagnetic objects within separator is essentially function of density, and independent of size or shape of objects. Results show close agreement between density of object and apparent density of ferrofluid required to float it. Results also demonstrate that very high separation rates are achievable by ferrofluid sink-float separation.

  12. Mass independent isotope separations

    International Nuclear Information System (INIS)

    Mass independent separations between isotopes of an element were first observed by Clayton on 17 O and 18 O from the Allende meteorite and attributed then to nucleosynthesis. Anomalous ratios of isotope abundance known at that time were due to nuclear processes. Later, atmospheric ozone and stratospheric CO2 were shown to exhibit mass independent isotope composition of oxygen. Several formation mechanisms of these 'anomalous' molecules have been proposed, none being completely satisfactory. In the laboratory, these mass independent chemical separation effects were eventually reproduced. Anomalous separations were also obtained between isotopes of uranium, and even of light elements such as magnesium. These were first connected with irregularities in atomic nucleus volumes. Such effects are not recorded on natural terrestrial samples. Two main reasons prevent such observations from having been made. Firstly, laboratories investigating isotope compositions of elements, publish almost exclusively deltas of one isotope only. But, to look for possible anomalies, one needs to compare each isotope abundance in a sample similar to that in the standard used as origin of deltas. An example of such calculation will be given. Secondly, deltas of isotopes published by different laboratories are usually not comparable to better than a few per mil. The reason is that, to calculate deltas, most laboratories use working standards whose absolute values may not be exactly established as they are not crucial to their work. Several per mil differences will be shown to be implied between the 'absolute' isotope abundance of 13 C of standards, reputedly the same, used by different laboratories. Laboratories making surveys of natural samples should be encouraged, e.g. by IUPAC, to cover every isotope of multiple isotope elements, and to make, at not infrequent intervals, a close comparison of their working standards with internationally distributed ones. (author)

  13. Method for separation of isotopes

    International Nuclear Information System (INIS)

    The initial material UCl6 flows through the separation facility in vaporous form, the mixture of isotopes being selectively excited by means of lasers. Separation of the excited molecules is done chemically or physically. The non-excited molecules get to an isotope balancing section, where the chlorine gas is supplied in natural composition with a quantitative ratio of 76 : 24 for 35Cl : 37Cl, and the UCl6 is restored to its original composition. This cycle is repeated for enrichment of 235U or 238U. (DG)

  14. Holographic Chiral Electric Separation Effect

    OpenAIRE

    Pu, Shi; Wu, Shang-Yu; Yang, Di-Lun

    2014-01-01

    We investigate the chiral electric separation effect, where an axial current is induced by an electric field in the presence of both vector and axial chemical potentials, in a strongly coupled plasma via the Sakai-Sugimoto model with an $U(1)_R\\times U(1)_L$ symmetry. By introducing different chemical potentials in $U(1)_R$ and $U(1)_L$ sectors, we compute the axial direct current (DC) conductivity stemming from the chiral current and the normal DC conductivity. We find that the axial conduct...

  15. 全膜分离技术及其在电厂化学水处理中的应用%Whole Membrane Separation Technology and Its Application in Chemical Water Treatment of Power Plant

    Institute of Scientific and Technical Information of China (English)

    马福刚

    2011-01-01

    This paper introduces the definition, types and characteristics of membrane separation technology, and application instance of whole membrane separation treatment process (UF-RO-EDI) in power plant boiler feed water treatment.%介绍了膜分离技术的定义、种类、特点以及全膜分离处理工艺(UF-RO-EDI)在电厂锅炉补给水处理中的应用实例.

  16. Physician-assisted death.

    OpenAIRE

    Senn, John S.

    1995-01-01

    Physician-assisted death includes both euthanasia and assistance in suicide. The CMA urges its members to adhere to the principles of palliative care. It does not support euthanasia and assisted suicide. The following policy summary includes definitions of euthanasia and assisted suicide, background information, basic ethical principles and physician concerns about legalization of physician-assisted death.

  17. Fictional Separation Logic

    DEFF Research Database (Denmark)

    Jensen, Jonas Buhrkal; Birkedal, Lars

    2012-01-01

    Separation logic formalizes the idea of local reasoning for heap-manipulating programs via the frame rule and the separating conjunction P * Q, which describes states that can be split into \\emph{separate} parts, with one satisfying P and the other satisfying Q. In standard separation logic......, separation means physical separation. In this paper, we introduce \\emph{fictional separation logic}, which includes more general forms of fictional separating conjunctions P * Q, where "*" does not require physical separation, but may also be used in situations where the memory resources described by P and Q...... overlap. We demonstrate, via a range of examples, how fictional separation logic can be used to reason locally and modularly about mutable abstract data types, possibly implemented using sophisticated sharing. Fictional separation logic is defined on top of standard separation logic, and both the meta...

  18. Separation Anxiety (For Parents)

    Science.gov (United States)

    ... 5 Things to Know About Zika & Pregnancy Separation Anxiety KidsHealth > For Parents > Separation Anxiety Print A A ... both of you get through it. How Separation Anxiety Develops Babies adapt pretty well to other caregivers. ...

  19. Identification of an Unknown Assistant Blowing Agent in AC Blowing System%一种助发泡剂的鉴定

    Institute of Scientific and Technical Information of China (English)

    何文绚; Robert Shanks

    2004-01-01

    In this study, TLC was used to separate and purify the unknown assistant blowing agent in AC blowing system. After that, FTIR-Microscope was used to indicate the functional group in the uncommon unknown compound. Through combination of FTIR analysis, elemental analysis and other physical and chemical analysis, the molecular structure of unknown was deduced. Finally by explaining mass spectra of the unknown compounds, the molecular structure of unknown was further confirmed.

  20. Microcellular foams via phase separation

    International Nuclear Information System (INIS)

    A study of wide variety of processes for making plastic foams shows that phase separation processes for polymers from solutions offers the most viable methods for obtaining rigid plastic foams which met the physical requirements for fusion target designs. Four general phase separation methods have been shown to give polymer foams with densities less than 0.1 g/cm3 and cell sizes of 30μm or less. These methods involve the utilization of non-solvent, chemical or thermal cooling processes to achieve a controlled phase separation wherein either two distinct phases are obtained where the polymer phase is a continuous phase or two bicontinuous phases are obtained where both the polymer and solvent are interpenetrating, continuous, labyrinthine phases. Subsequent removal of the solvent gives the final foam structure

  1. Separation of Fluids by Membrane Processes

    Czech Academy of Sciences Publication Activity Database

    Izák, Pavel

    Bratislava : Slovak Society of Chemical Engineering , 2013 - (Markoš, J.), s. 5 ISBN 978-80-89475-09-4. [International Conference of Slovak Society of Chemical Engineering /40./. Tatranské Matliare (SK), 27.05.2013-31.05.2013] R&D Projects: GA ČR GAP106/10/1194 Institutional support: RVO:67985858 Keywords : pervaporation * gas separation * supported ionic liquid membranes Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  2. Extraction process for separating Tc and Pd from waste solutions of nuclear fuel reprocessing. 3. Studies on the chemical stability and radiation resistance of tri-n-octylamine/tetrachloromethane

    Energy Technology Data Exchange (ETDEWEB)

    Gruendig, M.; Langguth, H.; Richter, M.

    1985-11-01

    The chemical stability and the radiation resistance of the extraction agents and the direct influence of the radiation on the extraction of technetium and palladium with TOA in CCl/sub 4/ has been investigated.

  3. Actinide separative chemistry

    International Nuclear Information System (INIS)

    Actinide separative chemistry has focused very heavy work during the last decades. The main was nuclear spent fuel reprocessing: solvent extraction processes appeared quickly a suitable, an efficient way to recover major actinides (uranium and plutonium), and an extensive research, concerning both process chemistry and chemical engineering technologies, allowed the industrial development in this field. We can observe for about half a century a succession of Purex plants which, if based on the same initial discovery (i.e. the outstanding properties of a molecule, the famous TBP), present huge improvements at each step, for a large part due to an increased mastery of the mechanisms involved. And actinide separation should still focus R and D in the near future: there is a real, an important need for this, even if reprocessing may appear as a mature industry. We can present three main reasons for this. First, actinide recycling appear as a key-issue for future nuclear fuel cycles, both for waste management optimization and for conservation of natural resource; and the need concerns not only major actinide but also so-called minor ones, thus enlarging the scope of the investigation. Second, extraction processes are not well mastered at microscopic scale: there is a real, great lack in fundamental knowledge, useful or even necessary for process optimization (for instance, how to design the best extracting molecule, taken into account the several notifications and constraints, from selectivity to radiolytic resistivity?); and such a need for a real optimization is to be more accurate with the search of always cheaper, cleaner processes. And then, there is room too for exploratory research, on new concepts-perhaps for processing quite new fuels- which could appear attractive and justify further developments to be properly assessed: pyro-processes first, but also others, like chemistry in 'extreme' or 'unusual' conditions (supercritical solvents, sono-chemistry, could be

  4. Path Separability of Graphs

    Science.gov (United States)

    Diot, Emilie; Gavoille, Cyril

    In this paper we investigate the structural properties of k-path separable graphs, that are the graphs that can be separated by a set of k shortest paths. We identify several graph families having such path separability, and we show that this property is closed under minor taking. In particular we establish a list of forbidden minors for 1-path separable graphs.

  5. Experimental study of stable isotope separation

    International Nuclear Information System (INIS)

    This paper presents some results of investigation into a gas centrifuge and gas centrifuge cascade. The chemical compounds of osmium - OsO4, tungsten - WF6 and xenon were chosen for centrifugal separation, and the centrifugal technology for the separation of osmium, tungsten and xenon were developed. The separation factors for molar mass differences, γ0, were obtained for OsO4, Xe, WF6 in a single gas centrifuge. The separation by gas centrifuge cascade has been done and some results of the investigation are shown. High abundance of 186W (>90 %), 129Xe (>65 %) and 192 Os (>99 %) was produced using the short cascade

  6. Hybrid Membrane-Distillation Separation for Ethylene Cracking

    OpenAIRE

    Etoumi, Assma S Abdalla

    2014-01-01

    Hybrid membrane-distillation separation for ethylene crackingAsma EtoumiThe University of Manchester2014Abstract – PhD ThesisGas separations are often required in chemical processes, e.g. air separation,ethylene production, etc. These are often challenging and costly processes because ofthe low temperature and high pressure needed if vapour-liquid phase separations areinvolved. This thesis focuses on hybrid membrane-distillation separations as anopportunity to develop more energy-efficient se...

  7. Membrane process for separation of trace contaminants

    International Nuclear Information System (INIS)

    Pressure driven membrane processes are controlled by size as well as physico-chemical interaction with the chemical matrix of the membrane. As the average pore-size of the membrane decreases from a few tenths of micron as in UF to a few nanometers in NF to a few angstroms in RO, the controlling mechanism changes from size exclusion to physico-chemical interactions. Consequently while the colloids, suspended matters etc. can be removed by UF, NF can separate multivalent and macromolecular species from monovalents and RO can separate water from the dissolved ionic contaminants allowing high volume reduction factors. UF as stand alone or in integration with established chemical processes is able to achieve separation of colloids, thus providing a viable solution for separation of trace water contaminants like iron, trace radiocontaminants etc. A recent bench scale study with low active waste stream of radio-contaminants generated in the department also showed promise in separation of trace amounts of 137Cs and 90Sr to achieve a DF at par with the established and practiced conventional system with much lower complexing chemical requirements. (author)

  8. Perfil dos dependentes químicos atendidos em uma unidade de reabilitação de um hospital psiquiátrico Perfil de los dependientes químicos atendidos en una unidad de rehabilitación de un hospital psiquiátrico The profile of the chemical dependants assisted in a rehabilitation unit of a psychiatric hospital

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Prado da Silva

    2010-09-01

    Full Text Available Pesquisa descritiva. Objetivo: caracterizar o perfil dos dependentes químicos atendidos na unidade de reabilitação de um hospital psiquiátrico.Participaram 30 dependentes químicos. Os dados foram coletados mediante entrevista. A faixa etária prevalente foi entre 26 e 33 anos: 50% estavam empregados; 77% perderam o emprego pelo menos uma vez pelo abuso de drogas; 80% tiveram episódios de separação relacionada com o uso de drogas; 11 participantes tinham diagnóstico de transtorno mental antes do internamento e, destes, 9 tentaram suicídio; 71% iniciaram o uso de drogas pelo álcool com maior prevalência na faixa etária dos 12 a 19 anos; 71% tiveram contato com a droga no meio familiar e 30% dos casos, por meio de amigos. O abuso dessas substâncias afeta pessoas em idade produtiva, adultos jovens, e prejudica o desempenho no trabalho e na relação familiar.Investigación descriptiva. Objetivo: caracterizar el perfil de los dependientes químicos atendidos en la unidad de rehabilitación de un hospital psiquiátrico. Participaron 30 dependientes químicos. Los datos fueron colectados por medio de entrevista. El grupo etario prevalente fue entre 26 y 33 años, 50% empleados; 77% perdió el empleo por lo menos una vez por abuso de drogas; el 80% tuvo episodios de separación relacionada con el uso de drogas; 11 participantes fueron diagnosticados con trastorno mental antes de la internación y de estos, 9 intentaron el suicidio; 71% inició el uso de drogas por el alcohol con mayor predominancia en el rango de edad de 12 hasta 19 años; 71% tuvo contacto con la droga en el ambiente familiar y en 30% de los casos fue a través de amigos. El abuso de esas sustancias afecta personas en edad productiva, adultos jóvenes, cuyo inicio ocurrió en el círculo familiar y afectó el desempeño en el trabajo y la relación familiar del usuario.Descriptive research with the aim of characterizing the profile of chemical dependants assisted in the

  9. Principle component analysis for radiotracer signal separation.

    Science.gov (United States)

    Kasban, H; Arafa, H; Elaraby, S M S

    2016-06-01

    Radiotracers can be used in several industrial applications by injecting the radiotracer into the industrial system and monitoring the radiation using radiation detectors for obtaining signals. These signals are analyzed to obtain indications about what is happening within the system or to determine the problems that may be present in the system. For multi-phase system analysis, more than one radiotracer is used and the result is a mixture of radiotracers signals. The problem is in such cases is how to separate these signals from each other. The paper presents a proposed method based on Principle Component Analysis (PCA) for separating mixed two radiotracer signals from each other. Two different radiotracers (Technetium-99m (Tc(99m)) and Barium-137m (Ba(137m))) were injected into a physical model for simulation of chemical reactor (PMSCR-MK2) for obtaining the radiotracer signals using radiation detectors and Data Acquisition System (DAS). The radiotracer signals are mixed and signal processing steps are performed include background correction and signal de-noising, then applying the signal separation algorithms. Three separation algorithms have been carried out; time domain based separation algorithm, Independent Component Analysis (ICA) based separation algorithm, and Principal Components Analysis (PCA) based separation algorithm. The results proved the superiority of the PCA based separation algorithm to the other based separation algorithm, and PCA based separation algorithm and the signal processing steps gives a considerable improvement of the separation process. PMID:26974488

  10. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  11. Magnetic Separation in Romania

    OpenAIRE

    Rezlescu, Nicolae; Bradu, Elena-Brandusa; Iacob, Gheorghe; Badescu, Vasile; Iacob, Lavinia

    1986-01-01

    The utilization of the magnetic separators of foreign and Romanian source is presented and the most important achievements in research, engineering design and manufacturing activity concerning the magnetic separation in Romania are reviewed.

  12. Magnetic Separation in Czechoslovakia

    OpenAIRE

    Hencl, Vladimir

    1991-01-01

    The use of magnetic separation in various mineral processing facilities in Czechoslovakia is described. The manufacture of assorted types of magnetic separation machines is highlighted. Potential applications and research and development activities are discussed.

  13. Ionene membrane battery separator

    Science.gov (United States)

    Moacanin, J.; Tom, H. Y.

    1969-01-01

    Ionic transport characteristics of ionenes, insoluble membranes from soluble polyelectrolyte compositions, are studied for possible application in a battery separator. Effectiveness of the thin film of separator membrane essentially determines battery lifetime.

  14. Separation anxiety in children

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001542.htm Separation anxiety in children To use the sharing features on this page, please enable JavaScript. Separation anxiety in children is a developmental stage during which ...

  15. Magnetic separation of algae

    Science.gov (United States)

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  16. Separations: A Short History and a Cloudy Crystal Ball

    Science.gov (United States)

    Wankat, Phil

    2009-01-01

    Separations have played a major role in the history of chemical engineering and will continue to be important. Since separations have always been a major cost item in the process industries, they have always been a critical key to successful commercialization. First, while reviewing the history of separation processes we will observe that many…

  17. Safety shutdown separators

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2015-06-30

    The present invention pertains to electrochemical cells which comprise (a) an anode; (b) a cathode; (c) a solid porous separator, such as a polyolefin, xerogel, or inorganic oxide separator; and (d) a nonaqueous electrolyte, wherein the separator comprises a porous membrane having a microporous coating comprising polymer particles which have not coalesced to form a continuous film. This microporous coating on the separator acts as a safety shutdown layer that rapidly increases the internal resistivity and shuts the cell down upon heating to an elevated temperature, such as 110.degree. C. Also provided are methods for increasing the safety of an electrochemical cell by utilizing such separators with a safety shutdown layer.

  18. Membrane Separation for Biogas Purification

    Czech Academy of Sciences Publication Activity Database

    Morávková, Lenka; Kárászová, Magda; Sedláková, Zuzana; Šimčík, Miroslav; Vejražka, Jiří; Izák, Pavel

    Praha : Česká společnost průmyslové chemie, 2015, s. 28 /p65./. ISBN 978-80-86238-73-9. [mezinárodní chemicko-technologická konference (ICCT 2015) /3./. Mikulov (CZ), 13.04.2015-15.04.2015] R&D Projects: GA TA ČR TE01020080; GA MŠk(CZ) LD13018 Institutional support: RVO:67985858 Keywords : membrane separation * biogas purification * biogas purification Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  19. Separation/preconcentration of ultra-trace levels of inorganic Sb and Se from different sample matrices by charge transfer sensitized ion-pairing using ultrasonic-assisted cloud point extraction prior to their speciation and determination by hydride generation AAS.

    Science.gov (United States)

    Altunay, Nail; Gürkan, Ramazan

    2016-10-01

    In the existing study, a new, simple and low cost process for separation/preconcentration of ultra-trace level of inorganic Sb and Se from natural waters, beverages and foods using ultrasonic-assisted cloud point extraction (UA-CPE) prior to their speciation and determination by hydride generation AAS, is proposed. The process is based on charge transfer sensitized complex formations of Sb(III) and Se(IV) with 3-amino-7-dimethylamino-2-methylphenazine hydrochloride (Neutral red, NRH(+)) in presence of pyrogallol and cetyltrimethylammonium bromide (CTAB) as both sensitivity enhancement and counter ion at pH 6.0. Under the optimized reagent conditions, the calibration curves were highly linear in the ranges of 8-300ngL(-1) and 12-250ngL(-1) (r(2)≥0.993) for Se(IV) and Sb(III), respectively. The limits of detection were 2.45 and 3.60ngL(-1) with sensitivity enhancement factors of 155 and 120, respectively. The recovery rate was higher than 96% with a relative standard deviation lower than 5.3% for five replicate measurements of 25, 75 and 150ngL(-1) Se(IV) and Sb(III), respectively. The method was validated by analysis of two certified reference materials (CRMs), and was successfully applied to the accurate and reliable speciation and determination of the contents of total Sb/Sb(III), and total Se/Se(IV) after UA-CPE of the pretreated sample matrices with and without pre-reduction with a mixture of l-cysteine and tartaric acid. Their Sb(V) and Se(VI) contents were calculated from the differences between total Sb and Sb(III) and/or total Se and Se(IV) levels. PMID:27474317

  20. Sustainable development of gree solvent separation process

    OpenAIRE

    Lisickov, Kiril; Fidancevska, Emilija; Grujic, Radoslav; Srebrenkoska, Vineta; Kuvendziev, Stefan

    2011-01-01

    Solvents defi ne a major part of the environmental performance of processes in the chemical industry and impact on cost, safety and health issues. The idea of green solvents expresses the goal to minimize the environmental impact resulting from the use of solvents in chemical production. In spite of conventional separation methods, precise process green technologies are based on the application of modern processes and process equipment as well as control and management...