Science.gov

Sample records for product monolith formation

  1. FLUIDIZED BED STEAM REFORMER (FBSR) PRODUCT: MONOLITH FORMATION AND CHARACTERIZATION

    SciTech Connect

    Jantzen, C

    2006-09-13

    The most important requirement for Hanford's low activity waste (LAW) form for shallow land disposal is the chemical durability of the product. A secondary, but still essential specification, is the compressive strength of the material with regards to the strength of the material under shallow land disposal conditions, e.g. the weight of soil overburden and potential intrusion by future generations, because the term ''near-surface disposal'' indicates disposal in the uppermost portion, or approximately the top 30 meters, of the earth's surface. The THOR{reg_sign} Treatment Technologies (TTT) mineral waste form for LAW is granular in nature because it is formed by Fluidized Bed Steam Reforming (FBSR). As a granular product it has been shown to be as durable as Hanford's LAW glass during testing with ASTM C-1285-02 known as the Product Consistency Test (PCT) and with the Single Pass Flow Through Test (SPFT). Hanford Envelope A and Envelope C simulants both performed well during PCT and SPFT testing and during subsequent performance assessment modeling. This is partially due to the high aluminosilicate content of the mineral product which provides a natural aluminosilicate buffering mechanism that inhibits leaching and is known to occur in naturally occurring aluminosilicate mineral analogs. In order for the TTT Na-Al-Si (NAS) granular mineral product to meet the compressive strength requirements (ASTM C39) for a Hanford waste form, the granular product needs to be made into a monolith or disposed of in High Integrity Containers (HIC's). Additionally, the Hanford intruder scenario for disposal in the Immobilized Low Activity Waste (ILAW) trench is mitigated as there is reduced intruder exposure when a waste form is in a monolithic form. During the preliminary testing of a monolith binder for TTT's FBSR mineral product, four parameters were monitored: (1) waste loading (not optimized for each waste form tested); (2) density; (3) compressive strength; and (4) durability

  2. Fluidized Bed Steam Reformer (FBSR) monolith formation

    SciTech Connect

    Jantzen, C.M.

    2007-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or 'mineralized' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydro-ceramics. All but one of the nine monoliths tested met the <2 g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydro-ceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form. (authors)

  3. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    SciTech Connect

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  4. Online preconcentration using monoliths in electrochromatography capillary format and microchips.

    PubMed

    Augustin, Violaine; Proczek, Gaëlle; Dugay, José; Descroix, Stéphanie; Hennion, Marie-Claire

    2007-11-01

    Online preconcentration and separation of analytes using an in situ photopolymerized hexyl acrylate-based monolith stationary phase was evaluated using electrochromatography in capillary format and microchip. The band broadening occurring during the preconcentration process by frontal electrochromatography and during the desorption process by elution electrochromatography was studied. The hexyl acrylate-based monolith provides high retention for neutral analytes allowing the handling of large sample volumes and its structure allows rapid mass transfer, thus reducing the band broadening. For moderately polar analytes such as mono-chlorophenols that are slightly retained in water, it was shown that enrichment factors up to 3500 can be obtained by a hydrodynamic injection of several bed volumes for 120 min under 0.8 MPa with a decrease in efficiency of 50% and a decrease of 30% for the resolution between 2- and 3-chlorophenol. An 8 min preconcentration time allows enrichment factors above 100 for polyaromatic hydrocarbons. The interest of these monoliths when synthesized in microchip is also demonstrated. A 200-fold enrichment was easily obtained for PAHs with only 1 min as preconcentration time, without decrease in efficiency.

  5. High productivity chromatographic separations on monolithic capillary columns

    NASA Astrophysics Data System (ADS)

    Korolev, A. A.; Shiryaeva, V. E.; Popova, T. P.; Kurganov, A. A.

    2013-03-01

    The productivity of monolithic capillary columns based on silica gel and polymers of different polarities (divinylbenzene and ethyleneglycol dimethacrylate) is investigated using a model mixture of light hydrocarbons. It is shown that the productivity of a column is noticeably affected by the type of gas carrier. The highest productivity is observed when using carbon dioxide or dinitrogen monoxide as the gas carrier. The lowest productivity is observed when uisng hydrogen or helium.

  6. Initial results for the silicon monolithically interconnected solar cell product

    NASA Technical Reports Server (NTRS)

    Dinetta, L. C.; Shreve, K. P.; Cotter, J. E.; Barnett, A. M.

    1995-01-01

    This proprietary technology is based on AstroPower's electrostatic bonding and innovative silicon solar cell processing techniques. Electrostatic bonding allows silicon wafers to be permanently attached to a thermally matched glass superstrate and then thinned to final thicknesses less than 25 micron. These devices are based on the features of a thin, light-trapping silicon solar cell: high voltage, high current, light weight (high specific power) and high radiation resistance. Monolithic interconnection allows the fabrication costs on a per watt basis to be roughly independent of the array size, power or voltage, therefore, the cost effectiveness to manufacture solar cell arrays with output powers ranging from milliwatts up to four watts and output voltages ranging from 5 to 500 volts will be similar. This compares favorably to conventionally manufactured, commercial solar cell arrays, where handling of small parts is very labor intensive and costly. In this way, a wide variety of product specifications can be met using the same fabrication techniques. Prototype solar cells have demonstrated efficiencies greater than 11%. An open-circuit voltage of 5.4 volts, fill factor of 65%, and short-circuit current density of 28 mA/sq cm at AM1.5 illumination are typical. Future efforts are being directed to optimization of the solar cell operating characteristics as well as production processing. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. These features make this proprietary technology an excellent candidate for a large number of consumer products.

  7. Production of novel polymer monolithic columns, with stationary phase gradients, using cyclic olefin co-polymer (COC) optical filters.

    PubMed

    Currivan, Sinéad; Connolly, Damian; Paull, Brett

    2012-06-07

    Polymer monolithic columns with controlled surface ligand density, providing stationary phase gradients within monolithic capillary columns, have been developed using photo-grafting through optical filters. Utilising commercially available cyclic olefin co-polymer (COC) films, the production of an optical filter capable of attenuating UV irradiation, in a tailored manner, was investigated. This novel optical filter was successfully applied to the surface modification of poly(BuMA-co-EDMA) monolithic columns in a multi-step grafting procedure. Fabricated columns were subjected to scanning capacitively coupled contactless conductivity (sC(4)D), to determine the distribution of the grafted functional groups, axially along the column. Further modification to produce a chelating stationary phase gradient of iminodiacetic acid (IDA) was demonstrated. To demonstrate the distribution of the IDA sites, a metal cation (Cu(2+)) was complexed to the IDA forming a chelate. Upon the formation of a complex of IDA with Cu(2+), an overall drop in conductive response was observed. The COC optical filter was also used in the fabrication of a grafted gradient of strong cation exchanger (SCX), sulphopropyl methacrylate (SPM) upon a polymer monolith, demonstrating the broader applicability of such a filter.

  8. Production of aligned microfibers and nanofibers and derived functional monoliths

    DOEpatents

    Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya; Omatete, Ogbemi

    2007-08-14

    The present invention comprises a method for producing microfibers and nanofibers and further fabricating derived solid monolithic materials having aligned uniform micro- or nanofibrils. A method for producing fibers ranging in diameter from micrometer-sized to nanometer-sized comprises the steps of producing an electric field and preparing a solid precipitative reaction media wherein the media comprises at least one chemical reactive precursor and a solvent having low electrical conductivity and wherein a solid precipitation reaction process for nucleation and growth of a solid phase occurs within the media. Then, subjecting the media to the electric field to induce in-situ growth of microfibers or nanofibers during the reaction process within the media causing precipitative growth of solid phase particles wherein the reaction conditions and reaction kinetics control the size, morphology and composition of the fibers. The fibers can then be wet pressed while under electric field into a solid monolith slab, dried and consolidated.

  9. The formation of NGC 3603 young starburst cluster: `prompt' hierarchical assembly or monolithic starburst?

    NASA Astrophysics Data System (ADS)

    Banerjee, Sambaran; Kroupa, Pavel

    2015-02-01

    The formation of very young massive clusters or `starburst' clusters is currently one of the most widely debated topic in astronomy. The classical notion dictates that a star cluster is formed in situ in a dense molecular gas clump. The stellar radiative and mechanical feedback to the residual gas energizes the latter until it escapes the system. The newly born gas-free young cluster eventually readjusts with the corresponding mass-loss. Based on the observed substructured morphologies of many young stellar associations, it is alternatively suggested that even the smooth-profiled massive clusters are also assembled from migrating less massive subclusters. A very young (age ≈ 1 Myr), massive (>104 M⊙) star cluster like the Galactic NGC 3603 young cluster (HD 97950) is an appropriate testbed for distinguishing between the above `monolithic' and `hierarchical' formation scenarios. A recent study by Banerjee & Kroupa demonstrates that the monolithic scenario remarkably reproduces the HD 97950 cluster. In particular, its shape, internal motion and the mass distribution of stars are found to follow naturally and consistently from a single model calculation undergoing ≈70 per cent by mass gas dispersal. In this work, we explore the possibility of the formation of the above cluster via hierarchical assembly of subclusters. These subclusters are initially distributed over a wide range of spatial volumes and have various modes of subclustering in both absence and presence of a background gas potential. Unlike the above monolithic initial system that reproduces HD 97950 very well, the same is found to be prohibitive with hierarchical assembly alone (with/without a gas potential). Only those systems which assemble promptly into a single cluster (in ≲1 Myr) from a close separation (all within ≲2 pc) could match the observed density profile of HD 97950 after a similar gas removal. These results therefore suggest that the NGC 3603 young cluster has formed essentially

  10. Using scanning contactless conductivity to optimise photografting procedures and capacity in the production of polymer ion-exchange monoliths.

    PubMed

    Gillespie, Eoin; Connolly, Damian; Paull, Brett

    2009-07-01

    Capacitively coupled contactless conductivity detection (C4D) is utilised as a simple, rapid and non-invasive technique for the quantitative evaluation of the ion-exchange capacity of charged polymer monoliths in capillary format. A charged monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) was photografted onto a 100 microm i.d. butyl methacrylate-co-ethylenedimethacrylate monolith in a number of discrete 10 mm zones. By varying the energy dose (J/cm2) during grafting of each zone, the grafting density and thus ion-exchange capacity could be precisely controlled. Ion-exchange capacity could be correlated with energy dose by measuring the conductive response of each grafted region using scanning C4D techniques. Repeatability of the scanning C4D method was excellent with % RSD values of 0.7% and 2.4% obtained for three replicate scans of the ungrafted and grafted regions of a single monolith, respectively. Repeatability of the photografting process on separate monoliths was also examined by comparison of C4D profiles. The spatial accuracy of photografting was probed using scanning C4D which could measure the conductive response of the monolith at measurement intervals as low as 1 mm along its entire length. Scanning C4D was also used for the real time visualisation of the equilibration of grafted zones to permit the optimisation of monolith washing procedures. Finally, scanning C4D was applied to the measurement of the ion-exchange capacity of butyl methacrylate-co-AMPS-co-ethylenedimethacrylate copolymers with a direct correlation between monolith conductive response and concentration of charged monomer in the polymerisation mixture. The longitudinal homogeneity of charge along the monolith was 0.3% RSD, demonstrating that the charged functional monomer was evenly dispersed throughout the bulk of the monolith. Ion-exchange capacity was cross validated chromatographically using breakthrough studies and found to closely correlate to within 1% of the

  11. Ballistic Performance Model of Crater Formation in Monolithic, Porous Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Miller, J. E.; Christiansen, E. L.; Deighton, K. D.

    2014-01-01

    Porous monolithic ablative systems insulate atmospheric reentry vehicles from reentry plasmas generated by atmospheric braking from orbital and exo-orbital velocities. Due to the necessity that these materials create a temperature gradient up to several thousand Kelvin over their thickness, it is important that these materials are near their pristine state prior to reentry. These materials may also be on exposed surfaces to space environment threats like orbital debris and meteoroids leaving a probability that these exposed surfaces will be below their prescribed values. Owing to the typical small size of impact craters in these materials, the local flow fields over these craters and the ablative process afford some margin in thermal protection designs for these locally reduced performance values. In this work, tests to develop ballistic performance models for thermal protection materials typical of those being used on Orion are discussed. A density profile as a function of depth of a typical monolithic ablator and substructure system is shown in Figure 1a.

  12. Screening α-glucosidase inhibitor from natural products by capillary electrophoresis with immobilised enzyme onto polymer monolith modified by gold nanoparticles.

    PubMed

    Zhang, Aizhu; Ye, Fanggui; Lu, Junyu; Zhao, Shulin

    2013-12-01

    A novel strategy for screening α-glucosidase inhibitors (AGIs) from natural products by capillary electrophoresis (CE) with an immobilised enzyme microreactor was developed. In this approach, gold nanoparticles (AuNPs) was first covalently attached to surface of the pores of the porous polymer capillary monolith via the formation of an Au-S bond, and α-glucosidase was then simply and stably immobilised onto AuNPs through the strong affinity of gold for amino groups of the enzyme. In order to profiling the activity of the immobilised α-glucosidase, the natural substrate was hydrolyzed by it and the yield of product was determined by CE. The amount of covalently attached α-glucosidase to the monolith was calculated to be about 30.0 μg/mg. The immobilised enzyme exhibited 80% activity after 25 runs, and only lost 7.6% of activity after 6 runs within 31 days. Screening of AGIs present in extracts of natural products by the proposed method was demonstrated.

  13. Formate Formation and Formate Conversion in Biological Fuels Production

    PubMed Central

    Crable, Bryan R.; Plugge, Caroline M.; McInerney, Michael J.; Stams, Alfons J. M.

    2011-01-01

    Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production. PMID:21687599

  14. Monolithic germanium/silicon avalanche photodiodes with 340 GHz gain-bandwidth product

    NASA Astrophysics Data System (ADS)

    Kang, Yimin; Liu, Han-Din; Morse, Mike; Paniccia, Mario J.; Zadka, Moshe; Litski, Stas; Sarid, Gadi; Pauchard, Alexandre; Kuo, Ying-Hao; Chen, Hui-Wen; Zaoui, Wissem Sfar; Bowers, John E.; Beling, Andreas; McIntosh, Dion C.; Zheng, Xiaoguang; Campbell, Joe C.

    2009-01-01

    Significant progress has been made recently in demonstrating that silicon photonics is a promising technology for low-cost optical detectors, modulators and light sources. It has often been assumed, however, that their performance is inferior to InP-based devices. Although this is true in most cases, one of the exceptions is the area of avalanche photodetectors, where silicon's material properties allow for high gain with less excess noise than InP-based avalanche photodetectors and a theoretical sensitivity improvement of 3 dB or more. Here, we report a monolithically grown germanium/silicon avalanche photodetector with a gain-bandwidth product of 340 GHz, a keff of 0.09 and a sensitivity of -28 dB m at 10 Gb s-1. This is the highest reported gain-bandwidth product for any avalanche photodetector operating at 1,300 nm and a sensitivity that is equivalent to mature, commercially available III-V compound avalanche photodetectors. This work paves the way for the future development of low-cost, CMOS-based germanium/silicon avalanche photodetectors operating at data rates of 40 Gb s-1 or higher.

  15. A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters

    PubMed Central

    Urban, Jiri; Svec, Frantisek; Fréchet, Jean M.J.

    2011-01-01

    An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. PMID:21915852

  16. A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters.

    PubMed

    Urban, Jiri; Svec, Frantisek; Fréchet, Jean M J

    2012-02-01

    An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel.

  17. Crosslinked, cryostructured Lactobacillus reuteri monoliths for production of 3-hydroxypropionaldehyde, 3-hydroxypropionic acid and 1,3-propanediol from glycerol.

    PubMed

    Zaushitsyna, Oksana; Dishisha, Tarek; Hatti-Kaul, Rajni; Mattiasson, Bo

    2017-01-10

    Crosslinked, cryostructured monoliths prepared from Lactobacillus reuteri cells were evaluated as potential immobilized whole-cell biocatalyst for conversion of glycerol, to potentially important chemicals for the biobased industry, i.e. 3-hydroxypropionaldehyde (3HPA), 3-hydroxypropionic acid (3HP) and 1,3-propanediol (1,3PDO). Glutaraldehyde, oxidized dextran and activated polyethyleneimine/modified polyvinyl alcohol (PEI/PVA) were evaluated as crosslinkers; the latter gave highly stable preparations with maintained viability and biocatalytic activity. Scanning electron microscopy of the PEI/PVA monoliths showed high density of crosslinked cells with wide channels allowing liquid flow through. Flux analysis of the propanediol-utilization pathway, incorporating glycerol/diol dehydratase, propionaldehyde dehydrogenase, 1,3PDO oxidoreductase, phosphotransacylase, and propionate kinase, for conversion of glycerol to the three chemicals showed that the maximum specific reaction rates were -562.6, 281.4, 62.4 and 50.5mg/gCDWh for glycerol consumption, and 3HPA (extracellular), 3HP and 1,3PDO production, respectively. Under optimal conditions using monolith operated as continuous plug flow reactor, 19.7g/L 3HPA was produced as complex with carbohydrazide at a rate of 9.1g/Lh and a yield of 77mol%. Using fed-batch operation, 1,3PDO and 3HP were co-produced in equimolar amounts with a yield of 91mol%. The monoliths embedded in plastic carriers showed high mechanical stability under different modes in a miniaturized plug flow reactor.

  18. Dual Layer Monolith ATR of Pyrolysis Oil for Distributed Synthesis Gas Production

    SciTech Connect

    Lawal, Adeniyi

    2012-09-29

    We have successfully demonstrated a novel reactor technology, based on BASF dual layer monolith catalyst, for miniaturizing the autothermal reforming of pyrolysis oil to syngas, the second and most critical of the three steps for thermochemically converting biomass waste to liquid transportation fuel. The technology was applied to aged as well as fresh samples of pyrolysis oil derived from five different biomass feedstocks, namely switch-grass, sawdust, hardwood/softwood, golden rod and maple. Optimization of process conditions in conjunction with innovative reactor system design enabled the minimization of carbon deposit and control of the H2/CO ratio of the product gas. A comprehensive techno-economic analysis of the integrated process using in part, experimental data from the project, indicates (1) net energy recovery of 49% accounting for all losses and external energy input, (2) weight of diesel oil produced as a percent of the biomass to be ~14%, and (3) for a demonstration size biomass to Fischer-Tropsch liquid plant of ~ 2000 daily barrels of diesel, the price of the diesel produced is ~$3.30 per gallon, ex. tax. However, the extension of catalyst life is critical to the realization of the projected economics. Catalyst deactivation was observed and the modes of deactivation, both reversible and irreversible were identified. An effective catalyst regeneration strategy was successfully demonstrated for reversible catalyst deactivation while a catalyst preservation strategy was proposed for preventing irreversible catalyst deactivation. Future work should therefore be focused on extending the catalyst life, and a successful demonstration of an extended (> 500 on-stream hours) catalyst life would affirm the commercial viability of the process.

  19. Miniature fuel cell with monolithically fabricated Si electrodes - Alloy catalyst formation -

    NASA Astrophysics Data System (ADS)

    Ogura, Daiki; Suzuki, Takahiro; Katayama, Noboru; Dowaki, Kiyoshi; Hayase, Masanori

    2013-12-01

    A novel Pd-Pt catalyst formation process was proposed for reduction of Pt usage. In our miniature fuel cells, porous Pt was used as the catalyst, and the Pt usage was quite high. To reduce the Pt usage, we have attempted to deposit Pt on porous Pd by galvanic replacement, and relatively large output was demonstrated. In this study, in order to reduce more Pt usage and explore the alloy catalyst formation process, atomic layer deposition by UPD-SLRR (Under Potential Deposition - Surface Limited Redox Replacement) was applied to the Pd-Pt catalyst formation. The new process was verified at each process steps by EDS elemental analysis, and the expected spectra were obtained. Prototype cells were constructed by the new process, and cell output was raised to 420mW/cm2 by the Pd-Pt catalyst from 125mW/cm2 with Pd catalyst.

  20. Monolithic spectrometer

    DOEpatents

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  1. Monolithic spectrometer

    DOEpatents

    Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

    1998-05-19

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

  2. Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths.

    PubMed

    Detobel, Frederik; Eghbali, Hamed; De Bruyne, Selm; Terryn, Herman; Gardeniers, Han; Desmet, Gert

    2009-10-30

    We report on the synthesis of siloxane-based monoliths in the presence of a two-dimensional, perfectly ordered array of micro-pillars. Both methyltrimethoxysilane- and tetramethoxysilane-based monoliths were considered. The obtained structures were analyzed using scanning-electron microscopy and can be explained from the general theory of surface-directed phase separation in confined spaces. The formed structures are to a large extent nearly exclusively determined by the ratio between the bulk domain size of the monolith on the one hand and the distance between the micro-pillars on the other hand. When this ratio is small, the presence of the pillars has nearly no effect on the morphology of the produced monoliths. However, when the ratio approaches unity and ascends above it, some new types of monolith morphologies are induced, two of which appear to have interesting properties for use as novel chromatographic supports. One of these structures (obtained when the domain size/inter-pillar distance ratio is around unity) is a 3D network of linear interconnections between the pillars, organized such that all skeleton branches are oriented perpendicular to the micro-pillar surface. A second interesting structure is obtained at even higher values of the domain size/inter-pillar distance ratio. In this case, each individual micro-pillar is uniformly coated with a mesoporous shell.

  3. Grafted macroporous polymer monolithic disks: a new format of scavengers for solution-phase combinatorial chemistry.

    PubMed

    Tripp, J A; Svec, F; Fréchet, J M

    2001-01-01

    Polyethylene encased porous poly(chloromethylstyrene-co-divinylbenzene) disks have been prepared by polymerization in a cylindrical glass mold and cut to a disk format. Following attachment of a free radical azo initiator 4,4'-azobis(4-cyanovaleric acid) to available functionalities at the surface of the pores, the polymerization of 2-vinyl-4,4-dimethylazlactone was initiated from the surface. To avoid an undesirable increase in flow resistance and to improve the yield of grafting, divinylbenzene was added to the polymerization mixture in order to form a layer of swellable reactive polymer gel within the pores. The use of these disks as scavenging filters to remove various amines from solutions in flow-through operations was demonstrated by effective removal of amines in a very short period of time from their solutions in a variety of solvents, even including alcohols and water.

  4. Catalyst assisted synthesis of initiator attached silica monolith particles via isocyanate-hydroxyl reaction for production of polystyrene bound chromatographic stationary phase of excellent separation efficiency.

    PubMed

    Ali, Faiz; Kim, Yune Sung; Lee, Jin Wook; Cheong, Won Jo

    2014-01-10

    Dibutyltin dichloride (DBTDC) was used as a catalyst to chemically bind 4-chloromehtylphenylisocynate (4-CPI) to porous monolithic silica particles via isocyanate-hydroxyl reaction, and the reaction product was reacted with sodium diethyldithiocarbamate (SDDC) to yield initiator attached silica monolith particles. Reversible addition-fragmentation transfer (RAFT) polymerization was taken place on them to result in polystyrene attached silica particles that showed excellent separation efficiency when packed in a chromatographic column (1.0 mm × 300 mm). The numbers of theoretical plates (N) of 56,500 is better than those of any commercially available HPLC or UHPLC column yet.

  5. Fischer-Tropsch Synthesis on Ceramic Monolith-Structured Catalysts

    SciTech Connect

    Wang, Yong; Liu, Wei

    2009-04-19

    This paper reports recent research results about impact of different catalyst bed configurations on FT reaction product distribution. A CoRe/γ-alumina catalyst is prepared in bulk particle form and tested in the packed bed reactor at a size of 60 to 100 mesh. The same catalyst is ball milled and coated on a ceramic monolith support structure of channel size about 1mm. The monolith catalyst module is tested in two different ways, as a whole piece and as well-defined channels. Steady-state reaction conversion is measured at various temperatures under constant H2/CO feed ratio of 2 and reactor pressure of 25 bar. Detailed product analysis is performed. Significant formation of wax is evident with the packed particle bed and with the monolith catalyst that is improperly packed. By contrast, the wax formation is not detected in the liquid product by confining the reactions inside the monolith channel. This study presents an important finding about the structured catalyst/reactor system that the product distribution highly depends on the way how the structured reactor is set up. Even if the same catalyst and same reaction conditions (T, P, H2/oil ratio) are used, hydrodynamics (or flow conditions) inside a structured channel can have a significant impact on the product distribution.

  6. Comparison of monolithic and microparticulate columns for reversed-phase liquid chromatography of tryptic digests of industrial enzymes in cleaning products.

    PubMed

    Beneito-Cambra, M; Herrero-Martínez, J M; Ramis-Ramos, G; Lindner, W; Lämmerhofer, M

    2011-10-14

    Enzymes of several classes used in the formulations of cleaning products were characterized by trypsin digestion followed by HPLC with UV detection. A polymeric monolithic column (ProSwift) was used to optimize the separation of both the intact enzymes and their tryptic digests. This column was adequate for the quality control of raw industrial enzyme concentrates. Then, monolithic and microparticulate columns were compared for peptide analysis. Under optimized conditions, the analysis of tryptic digests of enzymes of different classes commonly used in the formulation of cleaning products was carried out. Number of peaks, peak capacity and global resolution were obtained in order to evaluate the chromatographic performance of each column. Particulate shell-core C18 columns (Kinetex, 2.6 μm) showed the best performance, followed by a silica monolithic column (Chromolith RP-18e) and the conventional C18 packings (Gemini, 5 μm or 3 μm). A polymeric monolithic column (ProSwift) gave the worst performances. The proposed method was satisfactorily applied to the characterization of the enzymes present in spiked detergent bases and commercial cleaners.

  7. Monolithic Optoelectronic Integrated Circuit

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Walters, Wayne; Gustafsen, Jerry; Bendett, Mark

    1990-01-01

    Monolithic optoelectronic integrated circuit (OEIC) receives single digitally modulated input light signal via optical fiber and converts it into 16-channel electrical output signal. Potentially useful in any system in which digital data must be transmitted serially at high rates, then decoded into and used in parallel format at destination. Applications include transmission and decoding of control signals to phase shifters in phased-array antennas and also communication of data between computers and peripheral equipment in local-area networks.

  8. Application of a Burkholderia cepacia lipase-immobilized silica monolith to batch and continuous biodiesel production with a stoichiometric mixture of methanol and crude Jatropha oil

    PubMed Central

    2011-01-01

    Background The enzymatic production of biodiesel through alcoholysis of triglycerides has become more attractive because it shows potential in overcoming the drawbacks of chemical processes. In this study, we investigate the production of biodiesel from crude, non-edible Jatropha oil and methanol to characterize Burkholderia cepacia lipase immobilized in an n-butyl-substituted hydrophobic silica monolith. We also evaluate the performance of a lipase-immobilized silica monolith bioreactor in the continuous production of biodiesel. Results The Jatropha oil used contained 18% free fatty acids, which is problematic in a base-catalyzed process. In the lipase-catalyzed reaction, the presence of free fatty acids made the reaction mixture homogeneous and allowed bioconversion to proceed to 90% biodiesel yield after a 12 hour reaction time. The optimal molar ratio of methanol to oil was 3.3 to 3.5 parts methanol to one part oil, with water content of 0.6% (w/w). Further experiments revealed that B. cepacia lipase immobilized in hydrophobic silicates was sufficiently tolerant to methanol, and glycerol adsorbed on the support disturbed the reaction to some extent in the present reaction system. The continuous production of biodiesel was performed at steady state using a lipase-immobilized silica monolith bioreactor loaded with 1.67 g of lipase. The yield of 95% was reached at a flow rate of 0.6 mL/h, although the performance of the continuous bioreactor was somewhat below that predicted from the batch reactor. The bioreactor was operated successfully for almost 50 days with 80% retention of the initial yield. Conclusions The presence of free fatty acids originally contained in Jatropha oil improved the reaction efficiency of the biodiesel production. A combination of B. cepacia lipase and its immobilization support, n-butyl-substituted silica monolith, was effective in the production of biodiesel. This procedure is easily applicable to the design of a continuous flow

  9. Elastic and optical anisotropy of the single-coal monolithic high-temperature (HT) carbonization products obtained on a laboratory scale

    SciTech Connect

    Marta Krzesinska; Slawomira Pusz; Andrzej Koszorek

    2005-10-01

    The aim of the present study was to investigate the directional dependences of the elastic and optical properties of monolithic single-coal high-temperature (HT) carbonization products obtained on a laboratory scale (with very slow heating rate) from coals of different caking propensity. Sixteen monolithic HT carbonization products, mainly cokes, were produced in the Jenkner retort furnace using 16 various types of coals of varying rank (from 83.1 wt % carbon to 98.3 wt % carbon) with a Roga index (RI) in the range of 0-76. Coals were carbonized in the form of monolithic blocks. The physical parameters such as true density, porosity, ultrasonic velocity, and dynamic elastic moduli, as well as optical reflectance parameters (R{sub max}, R{sub min}, R{sub am}), were determined for the resultant products. The elastic and optical properties of the HT carbonization products were related to their porosity and the rank of the parent coals. It was determined that the HT carbonization products exhibit the different directional properties of the studied parameters, and they can be divided into three groups, with respect to the observed differences. The properties of these groups were related to the parent coal rank and the caking propensity (i.e., to the RI value). Anisotropy of the coke matrix structure was determined to be important for discussion about the anisotropic properties of cokes. 50 refs., 9 figs., 4 tabs.

  10. Selection of column dimensions and gradient conditions to maximize the peak-production rate in comprehensive off-line two-dimensional liquid chromatography using monolithic columns.

    PubMed

    Eeltink, Sebastiaan; Dolman, Sebastiaan; Vivo-Truyols, Gabriel; Schoenmakers, Peter; Swart, Remco; Ursem, Mario; Desmet, Gert

    2010-08-15

    The peak-production rate (peak capacity per unit time) in comprehensive off-line two-dimensional liquid chromatography (LC/x/LC) was optimized for the separation of peptides using poly(styrene-co-divinylbenzene) monolithic columns in the reversed-phase (RP) mode. A first-dimension ((1)D) separation was performed on a monolithic column operating at a pH of 8, followed by sequential analysis of all the (1)D fractions on a monolithic column operating at a pH of 2. To obtain the highest peak-production rate, effects of column length, gradient duration, and sampling time were examined. RP/x/RP was performed at undersampling conditions using a short 10 min (1)D gradient. The peak-production rate was highest using a 50 mm long (2)D column applying an 8-10 min (2)D gradient time and was almost a factor of two higher than when a 250 mm monolithic column was used. The best way to obtain a higher peak-production rate in off-line LC/x/LC proved to be an increase in the number of (1)D fractions collected. Increasing the (2)D gradient time was less effective. The potential of the optimized RP/x/RP method is demonstrated by analyzing proteomics samples of various complexities. Finally, the trade-off between peak capacity and analysis time is discussed in quantitative terms for both one-dimensional RP gradient-elution chromatography and the off-line two-dimensional (RP/x/RP) approach. At the conditions applied, the RP/x/RP approach provided a higher peak-production rate than the (1)D-LC approach when collecting three (1)D fractions, which corresponds to a total analysis time of 60 min.

  11. Facile preparation of silver nanoparticles homogeneously immobilized in hierarchically monolithic silica using ethylene glycol as reductant.

    PubMed

    Yu, Huan; Zhu, Yang; Yang, Hui; Nakanishi, Kazuki; Kanamori, Kazuyoshi; Guo, Xingzhong

    2014-09-07

    A facile and "green" method was proposed to introduce Ag nanoparticles (Ag NPs) into the hierarchically monolithic silica uniformly in the presence of (3-aminopropyl)-triethoxysilane (APTES) and ethylene glycol. APTES is used to modify the monolith by incorporating amino groups onto the surface of meso-macroporous skeletons, while ethylene glycol is employed as the productive reductant. Ag NPs are homogeneously immobilized in hierarchically monolithic silica after reduction and drying at 40 °C for different duration times, and the embedded amount of Ag NPs can reach 15.44 wt% when treated once. The embedment of Ag NPs increases with the repeat treatment and the APTES amount, without uncontrollable crystalline growth. The surface areas of Ag NPs embedded in silica monoliths after heat treatment at 300 and 400 °C are higher than those before heat treatment. The modification via APTES and the embedment of Ag NPs does not spoil the morphology of monolithic silica, while changing the pore structures of the monolith. A tentative formation process and a reduction mechanism are proposed for the modification, reduction and embedment. Ag NPs embedded in monolithic silica is promising for wide applications such as catalysis and separation.

  12. Monolith electroplating process

    DOEpatents

    Agarrwal, Rajev R.

    2001-01-01

    An electroplating process for preparing a monolith metal layer over a polycrystalline base metal and the plated monolith product. A monolith layer has a variable thickness of one crystal. The process is typically carried in molten salts electrolytes, such as the halide salts under an inert atmosphere at an elevated temperature, and over deposition time periods and film thickness sufficient to sinter and recrystallize completely the nucleating metal particles into one single crystal or crystals having very large grains. In the process, a close-packed film of submicron particle (20) is formed on a suitable substrate at an elevated temperature. The temperature has the significance of annealing particles as they are formed, and substrates on which the particles can populate are desirable. As the packed bed thickens, the submicron particles develop necks (21) and as they merge into each other shrinkage (22) occurs. Then as micropores also close (23) by surface tension, metal density is reached and the film consists of unstable metal grain (24) that at high enough temperature recrystallize (25) and recrystallized grains grow into an annealed single crystal over the electroplating time span. While cadmium was used in the experimental work, other soft metals may be used.

  13. A digital microfluidic method for in situ formation of porous polymer monoliths with application to solid-phase extraction.

    PubMed

    Yang, Hao; Mudrik, Jared M; Jebrail, Mais J; Wheeler, Aaron R

    2011-05-15

    We introduce the marriage of two technologies: digital microfluidics (DMF), a technique in which droplets are manipulated by application of electrostatic forces on an array of electrodes coated by an insulator, and porous polymer monoliths (PPMs), a class of materials that is popular for use for solid-phase extraction and chromatography. In this work, circular PPM discs were formed in situ by dispensing and manipulating droplets of monomer solutions to designated spots on a DMF device followed by UV-initiated polymerization. We used PPM discs formed in this manner to develop a digital microfluidic solid-phase extraction (DMF-SPE) method, in which PPM discs are activated and equilibrated, samples are loaded, PPM discs are washed, and the samples are eluted, all using microliter droplets of samples and reagents. The new method has extraction efficiency (93%) comparable to that of pipet-based ZipTips and is compatible with preparative sample extraction and recovery for on-chip desalting, removal of surfactants, and preconcentration. We anticipate that DMF-SPE may be useful for a wide range of applications requiring preparative sample cleanup and concentration.

  14. Elimination of formate production in Clostridium thermocellum

    DOE PAGES

    Rydzak, Thomas; Lynd, Lee R.; Guss, Adam M.

    2015-07-11

    We study the ability of Clostridium thermocellum to rapidly degrade cellulose and ferment resulting hydrolysis products into ethanol makes it a promising platform organism for cellulosic biofuel production via consolidated bioprocessing. Currently, however, ethanol yield are far below theoretical maximum due to branched product pathways that divert carbon and electrons towards formate, H2, lactate, acetate, and secreted amino acids. To redirect carbon and electron flux away from formate, pyruvate:formate lyase (pfl) and respective PFL-activating enzyme were deleted. Formate production in the resulting Δpfl strain was eliminated and acetate production decreased by 50% on both complex and defined medium. Growth ratemore » of Δpfl decreased by 2.9-fold on defined medium and diauxic growth was observed on complex medium. Supplementation of defined medium with 2 mM formate restored Δpfl growth rate to 80% of the parent strain. Finally, we discuss the role of pfl in metabolic engineering strategies and C1 metabolism.« less

  15. Surface modified aerogel monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

    2013-01-01

    This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

  16. Enantioselective nano liquid chromatographic separation of racemic pharmaceuticals: a facile one-pot in situ preparation of lipase-based polymer monoliths in capillary format.

    PubMed

    Ahmed, Marwa; Ghanem, Ashraf

    2014-11-01

    New affinity monolithic capillary columns of 150 µm internal diameter were prepared in situ fused glass capillary via either immobilization or encapsulation of Candida antarctica lipase B (CALB) on or within polymer monoliths, respectively. The immobilized lipase-based monoliths were prepared via copolymerization of 19.1% monomers (8.9% MMA and 10.2% GMA), 19.8% EDMA, and 61.1% porogens (54.2% formamide and 6.9% 1-propanol) w/w or 20% GMA, 20% EDMA, and 60% porogens (51.6% cyclohexanol and 8.4% 1-dodecanol) in the presence of AIBN (1%) as a radical initiator. This was followed by pumping a solution of lipase through the capillaries and rinsing with potassium phosphate buffer. On the other hand, the encapsulated lipase-based monoliths were prepared via copolymerization of 20% monomers (GMA), 20% EDMA, and 60% porogens (48% 1-propanol, 6% 1,4-butanediol) or 16.4% monomers (16% BuMA, 0.4% SPMA), 23.6% EDMA, and 60% porogens (36% 1-propanol, 18% 1,4-butanediol along with 6% lipase aqueous solution in potassium phosphate buffer. The prepared capillary columns were investigated for the enantioselective nano liquid chromatographic separation of a set of different classes of racemic pharmaceuticals, namely, α- and β-blockers, antiinflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs, and antiarrhythmic drugs. Run-to-run repeatability was quite satisfactory. The encapsulated lipase-based capillary monolith showed better enantioselective separations of most of the investigated compounds. Baseline separation was achieved for alprenolol, atenolol, bromoglutithimide, carbuterol, chloropheneramine, cizolertine carbinol, 4-hydroxy-3-methoxymandelic acid, desmethylcizolertine, nomifensine, normetanephrine, and sulconazole under reversed phase chromatographic conditions. A speculation about the understanding of the chiral recognition mechanism of

  17. Monolithic exploding foil initiator

    SciTech Connect

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  18. Scaling up of continuous-flow, microwave-assisted, organic reactions by varying the size of Pd-functionalized catalytic monoliths.

    PubMed

    He, Ping; Haswell, Stephen J; Fletcher, Paul D I; Kelly, Stephen M; Mansfield, Andrew

    2011-01-01

    A product-scalable, catalytically mediated flow system has been developed to perform Suzuki-Miyaura reactions under a microwave heating regime, in which the volumetric throughput of a Pd-supported silica monolith can be used to increase the quantity of the product without changing the optimal operating conditions. Two silica monoliths (both 3 cm long), with comparable pore diameters and surface areas, were fabricated with diameters of 3.2 and 6.4 mm to give volumetric capacities of 0.205 and 0.790 mL, respectively. The two monoliths were functionalized with a loading of 4.5 wt % Pd and then sealed in heat-shrinkable Teflon(®) tubing to form a monolithic flow reactor. The Pd-supported silica monolith flow reactor was then placed into the microwave cavity and connected to an HPLC pump and a backpressure regulator to minimize the formation of gas bubbles. The flow rate and microwave power were varied to optimize the reactant contact time and temperature, respectively. Under optimal reaction conditions the quantity of product could be increased from 31 mg per hour to 340 mg per hour simply by changing the volumetric capacity of the monolith.

  19. Fibrous monoliths: Economic ceramic matrix composites from powders [Final report

    SciTech Connect

    Rigali, Mark; Sutaria, Manish; Mulligan, Anthony; Creegan, Peter; Cipriani, Ron

    1999-05-26

    The project was to develop and perform pilot-scale production of fibrous monolith composites. The principal focus of the program was to develop damage-tolerant, wear-resistant tooling for petroleum drilling applications and generate a basic mechanical properties database on fibrous monolith composites.

  20. Making Online Products More Tangible: The Effect of Product Presentation Formats on Product Evaluations.

    PubMed

    Verhagen, Tibert; Vonkeman, Charlotte; van Dolen, Willemijn

    2016-07-01

    Although several studies have looked at the effects of online product presentations on consumer decision making, no study thus far has considered a potential key factor in online product evaluations: tangibility. The present study aims at filling this gap by developing and testing a model that relates different online product presentation formats to the three-dimensional concept of product tangibility. We test how the three tangibility dimensions influence perceived diagnosticity and, eventually, online purchase intentions. A between-subjects lab experiment (n = 366) was used to test the hypothesized effects of three common online product presentation formats (pictures vs. 360 spin rotation vs. virtual mirror). The results showed that out of these formats, virtual mirrors were superior in providing a sense of product tangibility, followed by the 360-spin rotation format and static pictures. Furthermore, in terms of predictive validity, two of the three tangibility dimensions significantly increased perceived diagnosticity, which, in turn, positively and strongly affected purchase intentions. Overall, our results add to previous works studying the relationships between online product presentation formats and consumer decision making. Also, they hold value for online practitioners by highlighting the potential benefits of applying technologically advanced product presentation formats such as the virtual mirror.

  1. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    NASA Astrophysics Data System (ADS)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  2. Development of a silica monolith modified with Fe3O4 nano-particles in centrifugal spin column format for the extraction of phosphorylated compounds.

    PubMed

    Alwy, Ali; Clarke, Sarah P; Brougham, Dermot F; Twamley, Brendan; Paull, Brett; White, Blánaid; Connolly, Damian

    2015-01-01

    In this study, citrate-stabilised iron oxide nano-particles (∼16 nm) have been immobilised on commercial silica monolithic centrifugal spin columns (MonoSpin) for the extraction of phosphorylated compounds. Two alternative strategies were adopted involving either direct electrostatic attachment to an aminated MonoSpin (single-layer method) in the first instance, or the use of a layer-by-layer method with poly(diallyldimethylammonium) chloride. Field-emission scanning electron spectroscopy and energy-dispersive X-ray spectroscopy was used for confirming notably higher coverage of nano-particles using the layer-by-layer method (2.49 ± 0.53 wt%) compared with the single-layer method (0.43 ± 0.30 wt%). The modified monolith was used for the selective separation/extraction of adenosine monophosphate, adenosine diphosphate and adenosine triphosphate with elution using a phosphate buffer. A reversed-phase liquid chromatographic assay was used for confirming that adenosine, as a non-phosphorylated control was not retained on the modified MonoSpin devices, whereas recovery of 80% for adenosine monophosphate, 86% for adenosine diphosphate and 82% for adenosine triphosphate was achieved.

  3. Monolithic microwave integrated circuits

    NASA Astrophysics Data System (ADS)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  4. Production from multiple zones of a tar sands formation

    DOEpatents

    Karanikas, John Michael; Vinegar, Harold J

    2013-02-26

    A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. Fluids are produced from the formation through at least one production well that is located in at least two zones in the formation. The first zone has an initial permeability of at least 1 darcy. The second zone has an initial of at most 0.1 darcy. The two zones are separated by a substantially impermeable barrier.

  5. Embedded-monolith armor

    DOEpatents

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  6. Drill-in fluid reduces formation damage, increases production rates

    SciTech Connect

    Hands, N.; Kowbel, K.; Nouris, R.

    1998-07-13

    A sodium formate drill-in fluid system reduced formation damage, resulting in better-than-expected production rates for an off-shore Dutch development well. Programmed to optimize production capacity and reservoir drainage from a Rotliegend sandstone gas discovery, the 5-7/8-in. subhorizontal production interval was drilled and completed barefoot with a unique, rheologically engineered sodium formate drill-in fluid system. The new system, consisting of a sodium formate (NaCOOH) brine as the base fluid and properly sized calcium carbonate as the formation-bridging agent, was selected on the basis of its well-documented record in reducing solids impairment and formation damage in similar sandstone structures in Germany. The system was engineered around the low-shear-rate viscosity (LSRV) concept, designed to provide exceptional rheological properties. After describing the drilling program, the paper gives results on the drilling and completion.

  7. A novel monolithic LEU foil target based on a PVD manufacturing process for (99)Mo production via fission.

    PubMed

    Hollmer, Tobias; Petry, Winfried

    2016-12-01

    (99)Mo is the most widely used radioactive isotope in nuclear medicine. Its main production route is the fission of uranium. A major challenge for a reliable supply is the conversion from highly enriched uranium (HEU) to low enriched uranium (LEU). A promising candidate to realize this conversion is the cylindrical LEU irradiation target. The target consists of a uranium foil encapsulated between two coaxial aluminum cladding cylinders. This target allows a separate processing of the irradiated uranium foil and the cladding when recovering the (99)Mo. Thereby, both the costs and the volume of highly radioactive liquid waste are significantly reduced compared to conventional targets. The presented manufacturing process is based on the direct coating of the uranium on the inside of the outer cladding cylinder. This process was realized by a cylindrical magnetron enhanced physical vapor deposition (PVD) technique. The method features a highly automated process, a good quality of the resulting uranium foils and a high material utilization.

  8. Monolithic Continuous-Flow Bioreactors

    NASA Technical Reports Server (NTRS)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  9. Electron Beam/Optical Hybrid Lithography For The Production Of Gallium Arsenide Monolithic Microwave Integrated Circuits (Mimics)

    NASA Astrophysics Data System (ADS)

    Nagarajan, Rao M.; Rask, Steven D.

    1988-06-01

    beam to optical with t 0.2μm (2 sigma) and (2) Electron beam to electron beam with f 0.lμm (2 sigma). These results suggest that the electron beam/optical hybrid lithography techniques could be used for MIMIC volume production as alignment tolerances required by GaAS chips are met in both cases. These results are discussed in detail.

  10. Monolithic MACS micro resonators

    NASA Astrophysics Data System (ADS)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  11. Monolithic Millimeter Wave Oscillator

    NASA Astrophysics Data System (ADS)

    Wang, Nan-Lei

    There is an increasing interest in the millimeter -wave spectrum for use in communications and for military and scientific applications. The concept of monolithic integration aims to produce very-high-frequency circuits in a more reliable, reproducible way than conventional electronics, and also at lower cost, with smaller size and lighter weight. In this thesis, a negative resistance device is integrated monolithically with a resonator to produce an effective oscillator. This work fills the void resulting from the exclusion of the local oscillator from the monolithic millimeter-wave integrated circuit (MMMIC) receiver design. For convenience a microwave frequency model was used to design the resonator circuit. A 5 GHz hybrid oscillator was first fabricated to test the design; the necessary GaAs process technology was developed for the fabrication. Negative resistance devices and oscillator theory were studied, and a simple but practical model of the Gunn diode was devised to solve the impedance matching problem. Monolithic oscillators at the Ka band (35 GHz) were built and refined. All devices operated in CW mode. By means of an electric-field probe, the output power was coupled into a metallic waveguide for measurement purposes. The best result was 3.63 mW of power output, the highest efficiency was 0.43% and the frequency stability was better than 10-4. In the future, an IMPATT diode could replace the Gunn device to give much higher power and efficiency. A varactor-tuned circuit also suitable for large-scale integration is under study.

  12. Development of oxide fibrous monolith systems.

    SciTech Connect

    Goretta, K. C.

    1999-03-02

    Fibrous monolithic ceramics generally have a cellular structure that consists of a strong cell surrounded by a weaker boundary phase [1-5]. Fibrous monoliths (FMs) are produced from powders by conventional ceramic fabrication techniques, such as extrusion [1,2]. When properly engineered, they exhibit fail gracefully [3-5]. Several compositions of ceramics and cermets have been processed successfully in fibrous monolithic form [4]. The most thoroughly investigated fibrous monolith consists of Si{sub 3}N{sub 4} cells and a BN cell-boundary phase [3-5]. Through appropriate selection of initial powders and extrusion and hot-pressing parameters, very tough final products have been produced. The resultant high toughness is due primarily to delamination during fracture along textured platelike BN grains. The primary objectives of our program are to develop: (1) Oxide-based FMs, including new systems with improved properties; (2) FMs that can be pressureless sintered rather than hot-pressed; (3) Techniques for continuous extrusion of FM filaments, including solid freeform fabrication (SFF) for net-shape fabrication of FMs; (4) Predictive micromechanical models for FM design and performance; and (5) Ties with industrial producers and users of FMs.

  13. Effects of formate on fermentative hydrogen production by Enterobacter aerogenes.

    PubMed

    Kurokawa, Tatsuo; Tanisho, Shigeharu

    2005-01-01

    This paper describes the effects of formate on fermentative hydrogen production by Enterobacter aerogenes by way of batch culture. When 20 mM formate was added to pH 6.3 and pH 5.8 E. aerogenes glucose cultures (formate culture) at the beginning of cultivation, hydrogen evolution through both glucose consumption and decomposition of the extrinsic formate occurred together, while hydrogen evolution occurred only through glucose consumption in the control cultures. The hydrogen evolution rates in the formate cultures were faster than in the control cultures, although cell growth and glucose consumption rates in the formate cultures were slower than the control cultures'. The decomposition rate of the extrinsic formate in the pH 5.8 formate culture was faster than in the pH 6.3 formate culture. The hydrogen yield from glucose in the pH 6.3 formate culture increased due to the increasing amount of the nicotinamide adenine dinucleotide for hydrogen production.

  14. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  15. Update On Monolithic Fuel Fabrication Development

    SciTech Connect

    C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

    2005-11-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

  16. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W.

    1991-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

  17. Design of monoliths through their mechanical properties.

    PubMed

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  18. Exploring transverse pattern formation in a dual-polarization self-mode-locked monolithic Yb: KGW laser and generating a 25-GHz sub-picosecond vortex beam via gain competition.

    PubMed

    Chang, M T; Liang, H C; Su, K W; Chen, Y F

    2016-04-18

    Formation of transverse modes in a dual-polarization self-mode-locked monolithic Yb: KGW laser under high-power pumping is thoroughly explored. It is experimentally observed that the polarization-resolved transverse patterns are considerably affected by the pump location in the transverse plane of the gain medium. In contrast, the longitudinal self-mode-locking is nearly undisturbed by the pump position, even under the high-power pumping. Under central pumping, a vortex beam of the Laguerre-Gaussian LGp,l mode with p = 1 and l = 1 can be efficiently generated through the process of the gain competition with a sub-picosecond pulse train at 25.3 GHz and the output power can be up to 1.45 W at a pump power of 10.0 W. Under off-center pumping, the symmetry breaking causes the transverse patterns to be dominated by the high-order Hermite-Gaussian modes. Numerical analyses are further performed to manifest the symmetry breaking induced by the off-center pumping.

  19. Monolithic optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Breunig, Ingo; Beckmann, Tobias; Buse, Karsten

    2012-02-01

    Stability and footprint of optical parametric oscillators (OPOs) strongly depend on the cavity used. Monolithic OPOs tend to be most stable and compact since they do not require external mirrors that have to be aligned. The most straightforward way to get rid of the mirrors is to coat the end faces of the nonlinear crystal. Whispering gallery resonators (WGRs) are a more advanced solution since they provide ultra-high reflectivity over a wide spectral range without any coating. Furthermore, they can be fabricated out of nonlinear-optical materials like lithium niobate. Thus, they are ideally suited to serve as a monolithic OPO cavity. We present the experimental realization of optical parametric oscillators based on whispering gallery resonators. Pumped at 1 μm wavelength, they generate signal and idler fields tunable between 1.8 and 2.5 μm wavelength. We explore different schemes, how to phase match the nonlinear interaction in a WGR. In particular, we show improvements in the fabrication of quasi-phase-matching structures. They enable great flexibility for the tuning and for the choice of the pump laser.

  20. Monolithic THz Frequency Multipliers

    NASA Technical Reports Server (NTRS)

    Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.

    2001-01-01

    Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.

  1. Monolithic ballasted penetrator

    DOEpatents

    Hickerson, Jr., James P.; Zanner, Frank J.; Baldwin, Michael D.; Maguire, Michael C.

    2001-01-01

    The present invention is a monolithic ballasted penetrator capable of delivering a working payload to a hardened target, such as reinforced concrete. The invention includes a ballast made from a dense heavy material insert and a monolithic case extending along an axis and consisting of a high-strength steel alloy. The case includes a nose end containing a hollow portion in which the ballast is nearly completely surrounded so that no movement of the ballast relative to the case is possible during impact with a hard target. The case is cast around the ballast, joining the two parts together. The ballast may contain concentric grooves or protrusions that improve joint strength between the case and ballast. The case further includes a second hollow portion; between the ballast and base, which has a payload fastened within this portion. The penetrator can be used to carry instrumentation to measure the geologic character of the earth, or properties of arctic ice, as they pass through it.

  2. A hierarchically porous cellulose monolith: A template-free fabricated, morphology-tunable, and easily functionalizable platform.

    PubMed

    Xin, Yuanrong; Xiong, Qiancheng; Bai, Qiuhong; Miyamoto, Miwa; Li, Cong; Shen, Yehua; Uyama, Hiroshi

    2017-02-10

    Recently, monoliths with continuous porous structure have received much attention for high-performance separation/adsorption matrix in biomedical and environmental fields. This study proposes a novel route to prepare cellulose monoliths with hierarchically porous structure by selecting cellulose acetate (CA) as the starting material. Thermally induced phase separation of CA solution using a mixed solvent affords a CA monolith, which is converted into the cellulose monolith by alkaline hydrolysis. Scanning electron microscopy images of the CA and cellulose monoliths reveal a continuous macropore with rough surface, and nitrogen adsorption/desorption analysis indicates the formation of a mesoporous structure. The macroporous structure could be controlled by changing the fabrication parameters. A series of reactive groups are introduced by chemical modifications on the surface of the cellulose monolith. The facile and diverse modifiability combined with its hydrophilic property make the hierarchically porous cellulose monolith a potential platform for use in separation, purification and bio-related applications.

  3. Primordial black holes formation from particle production during inflation

    SciTech Connect

    Erfani, Encieh

    2016-04-01

    We study the possibility that particle production during inflation can source the required power spectrum for dark matter (DM) primordial black holes (PBH) formation. We consider the scalar and the gauge quanta production in inflation models, where in the latter case, we focus in two sectors: inflaton coupled i) directly and ii) gravitationally to a U(1) gauge field. We do not assume any specific potential for the inflaton field. Hence, in the gauge production case, in a model independent way we show that the non-production of DM PBHs puts stronger upper bound on the particle production parameter. Our analysis show that this bound is more stringent than the bounds from the bispectrum and the tensor-to-scalar ratio derived by gauge production in these models. In the scenario where the inflaton field coupled to a scalar field, we put an upper bound on the amplitude of the generated scalar power spectrum by non-production of PBHs. As a by-product we also show that the required scalar power spectrum for PBHs formation is lower when the density perturbations are non-Gaussian in comparison to the Gaussian density perturbations.

  4. Coptis chinensis Polysaccharides Inhibit Advanced Glycation End Product Formation.

    PubMed

    Yang, Ye; Li, Yun; Yin, Dengke; Chen, Song; Gao, Xiangdong

    2016-06-01

    Coptis chinensis Franch (Huanglian) is commonly used to treat diabetes in China. In this study, the effects of the C. chinensis Franch polysaccharides (CCP) on advanced glycation end product (AGE) formation in vitro and in streptozotocin-induced diabetic mice were investigated. CCP significantly inhibited all the three periods of nonenzymatic protein glycation in vitro, including Amadori product, dicarbonyl compound, and AGE formation (P < .01). In diabetic mice, the administration of CCP not only improved both bodyweight and serum insulin and decreased fasting blood glucose and glycated serum protein concentrations but also decreased the AGE accumulations and morphological abnormalities in pancreas and liver. The inhibitory effects of CCP on AGE formation afford a potential therapeutic use in the prevention and treatment of diabetes.

  5. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, T.C.

    1993-03-30

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  6. Monolithically compatible impedance measurement

    DOEpatents

    Ericson, Milton Nance; Holcomb, David Eugene

    2002-01-01

    A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

  7. Monolithic microchannel heatsink

    DOEpatents

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  8. Monolithic microchannel heatsink

    DOEpatents

    Benett, W.J.; Beach, R.J.; Ciarlo, D.R.

    1996-08-20

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density. 9 figs.

  9. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, Thomas C.

    1993-01-01

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  10. Siderophore production and biofilm formation as linked social traits.

    PubMed

    Harrison, Freya; Buckling, Angus

    2009-05-01

    The virulence of pathogenic microbes can depend on individual cells cooperating in the concerted production of molecules that facilitate host colonization or exploitation. However, cooperating groups can be exploited by social defectors or 'cheats'. Understanding the ecology and evolution of cooperation is therefore relevant to clinical microbiology. We studied two genetically linked cooperative traits involved in host exploitation by the opportunistic human pathogen Pseudomonas aeruginosa. Clones that defected from cooperative production of iron-scavenging siderophores were deficient in biofilm formation. The presence of such clones in mixed biofilms with a wild-type clone led to reduced biofilm mass. The fitness advantage of siderophore-deficient mutants in the presence of wild-type bacteria was no greater in biofilm than in planktonic culture, suggesting that these mutants did not gain an additional advantage by exploiting wild-type biofilm polymer. Reduced biofilm formation therefore represents a pleiotropic cost of defection from siderophore production.

  11. Uncooled monolithic ferroelectric IRFPA technology

    NASA Astrophysics Data System (ADS)

    Belcher, James F.; Hanson, Charles M.; Beratan, Howard R.; Udayakumar, K. R.; Soch, Kevin L.

    1998-10-01

    Once relegated to expensive military platforms, occasionally to civilian platforms, and envisioned for individual soldiers, uncooled thermal imaging affords cost-effective solutions for police cars, commercial surveillance, driving aids, and a variety of other industrial and consumer applications. System prices are continuing to drop, and swelling production volume will soon drive prices substantially lower. The impetus for further development is to improve performance. Hybrid barium strontium titanate (BST) detectors currently in production are relatively inexpensive, but have limited potential for improved performance. The MTF at high frequencies is limited by thermal conduction through the optical coating. Microbolometer arrays in development at Raytheon have recently demonstrated performance superior to hybrid detectors. However, microbolometer technology lacks a mature, low-cost system technology and an abundance of upgradable, deployable system implementations. Thin-film ferroelectric (TFFE) detectors have all the performance potential of microbolometers. They are also compatible with numerous fielded and planned system implementations. Like the resistive microbolometer, the TFFE detector is monolithic; i.e., the detector material is deposited directly on the readout IC rather than being bump bonded to it. Imaging arrays of 240 X 320 pixels have been produced, demonstrating the feasibility of the technology.

  12. Formative Assessment Probes: Talk Moves. A Formative Assessment Strategy for Fostering Productive Probe Discussions

    ERIC Educational Resources Information Center

    Keeley, Page

    2016-01-01

    Formative assessment probes can be used to foster productive science discussions in which students make their thinking visible to themselves, their peers, and the teacher. During these discussions, there is an exchange between the teacher and students that encourages exploratory thinking, supports careful listening to others' ideas, asks for…

  13. Radarsat Geophysical Processor System: Data Products, Formats, and Visualization

    NASA Astrophysics Data System (ADS)

    Kerin, B. L.; Gens, R.; Baker, E.

    2003-12-01

    Radarsat Geophysical Processor System (RGPS) is designed to generate products that provide estimates of sea ice motion, deformation and sea ice thickness. The system uses Radarsat-1 ScanSAR Wide B (SWB) imagery acquired over the last six years over the entire Arctic Ocean. At the beginning of each winter season a regular grid with a default spacing of 10 km is initialized that defines the freeze up ice condition. With changing ice condition this regular grid distorts in shape and location. The distorted Langrangian grid is stored as an RGPS data product that reflects the ice condition at a particular time. In the past, RGPS products have been used to study processes operating at the scale of the entire Arctic Ocean. We are looking into the use of the RGPS data in a more refined grid, so that the product could also be used for studying smaller regions of interest. We have converted the specific binary format of the RGPS product to the more popular ARC/INFO polygon coverage format used by a wider research community. Finally, we have developed a visualization tool that will allow the user to drape the RGPS product containing ice attribute information over the corresponding synthetic aperture radar images and view a series of images showing change in ice condition over time.

  14. Monolithic microcircuit techniques and processes

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1972-01-01

    Brief discussions of the techniques used to make dielectric and metal thin film depositions for monolithic circuits are presented. Silicon nitride deposition and the properties of silicon nitride films are discussed. Deposition of dichlorosilane and thermally grown silicon dioxide are reported. The deposition and thermal densification of borosilicate, aluminosilicate, and phosphosilicate glasses are discussed. Metallization for monolithic circuits and the characteristics of thin films are also included.

  15. Formation and Stability of Radiation Products in Europa's Icy Shell

    NASA Technical Reports Server (NTRS)

    Moore, M. H.; Hudson, R. L.; Carlson, R. W.; Ferrante, R. F.

    2004-01-01

    Spectra of Europa reveal a surface dominated by water-ice along with hydrated materials and minor amounts of SO2, CO2, and H2O2. Jovian magnetospheric ions (protons, sulfur, and oxygen) and electrons produce significant chemical modifications of the surface on time scales of a few years at micrometer depths. Our laboratory studies examine the formation and stability of radiation products in H2O-rich ices relevant to Europa. Infrared (IR) spectra of ices before and after irradiation reveal the radiation destruction of molecules and the formation of products at 86 - 132 K. In addition, spectra of ices during warming track thermal evolution due to chemical changes and sublimation processes. IR-identified radiation products in 86 - 132 K irradiated H2O + SO2 ices are the bisulfate ion, HSO4(-), sulfate ion, SO4(2-) and the hydronium ion, H3O(+). Warming results in the formation of a residual spectrum similar to liquid sulfuric acid, H2SO4, for H2O:SO2 ratios of 30:1, whereas hydrated sulfuric acid, H2SO4 4 H2O, forms for ratios of 30:1. Radiation products identified for irradiated H2O + H2S ices at 86 K are H2S2 and SO2. When irradiated at 110 and 132 K, ices with H2O:H2S ratios if either 3:1 or 30:1 show the formation of H2SO4 4 H2O on warming to 175 K. We have also examined the radiation stability of H2SO4. Addition of CO2 to H2O + SO2 ices results in the formation of CO3 at 2046 cm (sup -1) (4.89 m). This is the strongest band from a carbon-containing product in the mid-IR spectral region, and it is also seen when either pure CO2 or H2O + CO2 ice is irradiated. Experiments with CH4 added to H2O + SO2 + CO2 ices addressed the question of methane's use as a marker of methanogens in an irradiated ice environment. New results on the near-IR spectrum of pure H2O2 will be included in this presentation. Interpretations of near-IR water bands, with H2O2 present, will be discussed. Irradiations of H2O2 and H2O + H2O2 mixtures, to examine the possibility of O2 and O3

  16. Monolithic Michelson Interferometer as ultra stable wavelength reference

    NASA Astrophysics Data System (ADS)

    Wan, Xiaoke; Ge, Jian

    2010-07-01

    Ultra-stable Monolithic Michelson interferometer can be an ideal reference for highprecision applications such as RV measurement in planet searching and orbit study. The advantages include wide wavelength range, simple sinusoidal spectral format, and high optical efficiency. In this paper, we report that a monolithic Michelson interferometers has been in-house developed with minimized thermal sensitivity with compensation tuning. With a scanning white light interferometer, the thermal sensitivity is measured ~ 6x10-7/°C at 550 nm and it decreases to zero near 1000 nm. We expect the wideband wavelength reference source to be stabilized better than 0.3 m/s for RV experiments

  17. Reducing the potential for processing contaminant formation in cereal products

    PubMed Central

    Curtis, Tanya Y.; Postles, Jennifer; Halford, Nigel G.

    2014-01-01

    Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue. PMID:24882936

  18. Reducing the potential for processing contaminant formation in cereal products.

    PubMed

    Curtis, Tanya Y; Postles, Jennifer; Halford, Nigel G

    2014-05-01

    Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue.

  19. Enhanced product formation in continuous fermentations with microbial cell recycle

    SciTech Connect

    Bull, D.N.; Young, M.D.

    1981-02-01

    The effect of partial recycle of microbial cells on the operation of a chemostat has been investigated for two fermentations. Stable steady states with and without partial cell recycle were obtained for the conversion of d-sorbitol to L-sorbose by Gluconobacter oxydans subsp. suboxydans 1916B and for the conversion of glucose to 2-ketogluconic acid by Serratia marcescens NRRl B-486. The employment of partial cell recycle dramatically increased product formation rates for both fermentations.

  20. Method and apparatus for production of subsea hydrocarbon formations

    DOEpatents

    Blandford, Joseph W.

    1994-01-01

    A well tender system for controlling, separating, storing and offloading well fluids produced from subsea hydrocarbon formations. The system comprises a vertically aligned series of tethered cylindrical tanks which are torsionally stabilized by flexible catenary production riser and export riser bundles, and serviced by separate catenary pipe bundles. Piles are secured to the seabed, each pile assembly being pivotally connected to a lower rigid tendon, which is in turn connected to tendons arranged about the periphery of the interconnected cylindrical tanks.

  1. Method and apparatus for production of subsea hydrocarbon formations

    DOEpatents

    Blandford, Joseph W.

    1992-01-01

    A well tender system for controlling, separating, storing and offloading well fluids produced from subsea hydrocarbon formations. The system comprises a vertically aligned series of tethered cylindrical tanks which are torsionally stabilized by flexible catenary production riser and expert riser bundles, and serviced by separate catenary pipe bundles. Piles are secured to the seabed, each pile assembly being pivotally connected to a lower rigid tendon, which is in turn connected to tendons arranged about the periphery of the interconnected cylindrical tanks.

  2. Improved methods of forming monolithic integrated circuits having complementary bipolar transistors

    NASA Technical Reports Server (NTRS)

    Bohannon, R. O., Jr.; Cashion, W. F.; Stehlin, R. A.

    1971-01-01

    Two new processes form complementary transistors in monolithic semiconductor circuits, require fewer steps /infusions/ than previous methods, and eliminate such problems as nonuniform h sub FE distribution, low yield, and large device formation.

  3. Monolithic afocal telescope

    NASA Technical Reports Server (NTRS)

    Roberts, William T. (Inventor)

    2010-01-01

    An afocal monolithic optical element formed of a shallow cylinder of optical material (glass, polymer, etc.) with fast aspheric surfaces, nominally confocal paraboloids, configured on the front and back surfaces. The front surface is substantially planar, and this lends itself to deposition of multi-layer stacks of thin dielectric and metal films to create a filter for rejecting out-of-band light. However, an aspheric section (for example, a paraboloid) can either be ground into a small area of this surface (for a Cassegrain-type telescope) or attached to the planar surface (for a Gregorian-type telescope). This aspheric section of the surface is then silvered to create the telescope's secondary mirror. The rear surface of the cylinder is figured into a steep, convex asphere (again, a paraboloid in the examples), and also made reflective to form the telescope's primary mirror. A small section of the rear surface (approximately the size of the secondary obscuration, depending on the required field of the telescope) is ground flat to provide an unpowered surface through which the collimated light beam can exit the optical element. This portion of the rear surface is made to transmit the light concentrated by the reflective surfaces, and can support the deposition of a spectral filter.

  4. Low nanopore connectivity limits gas production in Barnett formation

    NASA Astrophysics Data System (ADS)

    Hu, Qinhong; Ewing, Robert P.; Rowe, Harold D.

    2015-12-01

    Gas-producing wells in the Barnett Formation show a steep decline from initial production rates, even within the first year, and only 12-30% of the estimated gas in place is recovered. The underlying causes of these production constraints are not well understood. The rate-limiting step in gas production is likely diffusive transport from matrix storage to the stimulated fracture network. Transport through a porous material such as shale is controlled by both geometry (e.g., pore size distribution) and topology (e.g., pore connectivity). Through an integrated experimental and theoretical approach, this work finds that the Barnett Formation has sparsely connected pores. Evidence of low pore connectivity includes the sparse and heterogeneous presence of trace levels of diffusing solutes beyond a few millimeters from a sample edge, the anomalous behavior of spontaneous water imbibition, the steep decline in edge-accessible porosity observed in tracer concentrations following vacuum saturation, the low (about 0.2-0.4% by volume) level presence of Wood's metal alloy when injected at 600 MPa pressure, and high tortuosity from mercury injection capillary pressure. Results are consistent with an interpretation of pore connectivity based on percolation theory. Low pore connectivity of shale matrix limits its mass transfer interaction with the stimulated fracture network from hydraulic fracturing and serves as an important underlying cause for steep declines in gas production rates and a low overall recovery rate.

  5. Theoretical aspects of product formation from the NCO + NO reaction

    SciTech Connect

    Lin, M.C.; He, Y. ); Melius, C.F. )

    1993-09-09

    The reaction of NCO with NO, an important elementary process involved in the reduction of NO[sub x] by HNCO, has been studied theoretically using the BAC-MP4 technique in conjunction with RRKM calculations. The computed molecular structures and thermochemical data for various intermediates and transition states suggest that the reaction takes place primarily via the singlet, ground electronic state OCNNO molecule according to the following mechanism; (step a) NCO + NO [leftrightarrow] [sup 1]OCNNO [yields] N[sub 2]O + CO; (step b) NCO + NO [leftrightarrow] [sup 1]OCNNO [yields] c-OCNNO[minus] N[sub 2] + CO[sub 2]. The formation of N[sub 2]O + CO occurs by the fragmentation of the singlet OCNNO intermediate step (a), whereas the production of N[sub 2] + CO[sub 2] by cyclization-fragmentation occurs via step b. The tight transition states leading to the formation of these products, coupled with the loose entrance channel, give rise to the experimentally observed strong negative temperature dependence which can be quantitatively accounted for by the results of RRKM calculations based on the BAC-MP4 data. The experimentally measured product branching ratio for channels a and b could be accounted for theoretically by lowering the calculated energy barrier for step a by 3.6 kcal/mol, corresponding to about 15% of the barrier height. 22 refs., 3 figs., 5 tabs.

  6. Geochemical modeling of scale formation, and formation damage during production from sulfate and carbonate mineral-bearing reservoirs

    SciTech Connect

    Macgowan, D.B.; Dunn, T.L.; Surdam, R.C. )

    1991-03-01

    The physical and chemical processes that affect reservoir fluids during production can be modeled by methodologies similar to those used for modeling clastic diagenesis. That these processes may result in formation damage and scale formation make them of interest to production geologists and engineers. Pathway modeling, based upon a series of critical divides, predicts which reactions are likely to occur between formation, production tubing, and reservoir fluids. Thermodynamic equilibria modeling calculates direction and magnitude of possible reactions. Integration of these approaches with observations of patterns of scale formation, production line, and formation damage yield a model capable of predicting the magnitude and direction of reactions that may produce negative impacts on reservoir production. Critical divides characterizing these processes in carbonate and sulfate mineral-bearing reservoirs include: (1) presence or absence of sulfate-bearing minerals within the production volume; (2) presence of iron within production line or formation; (3) ratio of concentration of bicarbonate to hydrogen sulfide; (4) capacity of aqueous and solid phases to buffer formation fluid pH; and (5) magnitude of pressure and temperature drops during production. The model qualitatively predicts: (1) likelihood of sulfide, sulfate, or carbonate mineral precipitation during production; (2) souring of the reservoir; and (3) corrosion of production tubing. The model has been developed from production histories for Weber Sandstone reservoirs, Colorado and Wyoming, and has been applied to examples of reservoir production from Tensleep and Minnelusa reservoirs in Wyoming.

  7. Kinetics, products, and mechanisms of secondary organic aerosol formation.

    PubMed

    Ziemann, Paul J; Atkinson, Roger

    2012-10-07

    Secondary organic aerosol (SOA) is formed in the atmosphere when volatile organic compounds (VOCs) emitted from anthropogenic and biogenic sources are oxidized by reactions with OH radicals, O(3), NO(3) radicals, or Cl atoms to form less volatile products that subsequently partition into aerosol particles. Once in particles, these organic compounds can undergo heterogenous/multiphase reactions to form more highly oxidized or oligomeric products. SOA comprises a large fraction of atmospheric aerosol mass and can have significant effects on atmospheric chemistry, visibility, human health, and climate. Previous articles have reviewed the kinetics, products, and mechanisms of atmospheric VOC reactions and the general chemistry and physics involved in SOA formation. In this article we present a detailed review of VOC and heterogeneous/multiphase chemistry as they apply to SOA formation, with a focus on the effects of VOC molecular structure on the kinetics of initial reactions with the major atmospheric oxidants, the subsequent reactions of alkyl, alkyl peroxy, and alkoxy radical intermediates, and the composition of the resulting products. Structural features of reactants and products discussed include compound carbon number; linear, branched, and cyclic configurations; the presence of C[double bond, length as m-dash]C bonds and aromatic rings; and functional groups such as carbonyl, hydroxyl, ester, hydroxperoxy, carboxyl, peroxycarboxyl, nitrate, and peroxynitrate. The intention of this review is to provide atmospheric chemists with sufficient information to understand the dominant pathways by which the major classes of atmospheric VOCs react to form SOA products, and the further reactions of these products in particles. This will allow reasonable predictions to be made, based on molecular structure, about the kinetics, products, and mechanisms of VOC and heterogeneous/multiphase reactions, including the effects of important variables such as VOC, oxidant, and NO

  8. Highly bioactive polysiloxane modified bioactive glass-poly(ethylene glycol) hybrids monoliths with controlled surface structure for bone tissue regeneration

    NASA Astrophysics Data System (ADS)

    Chen, Jing; Que, Wenxiu; Xing, Yonglei; Lei, Bo

    2015-03-01

    Crack-free monoliths with controllable surface microstructure have high bioactivities and therefore potential applications in bone tissue regeneration. In this paper, crack-free polydimethylsiloxane-modified bioactive glass-poly (ethylene glycol) (PDMS-BG-PEG) hybrids monoliths were fabricated via using a modified sol-gel process. Results show that the addition of PEG plays an important part in the formation of crack-free and gelation of the monoliths, and surface microstructures of the as-prepared hybrid monoliths were significantly influenced by the concentration and molecular weight of PEG. The samples obtained from PEG 300 had porous surface result in higher bioactivity (apatite formation) in simulated body fluid (SBF), while the samples obtained from PEG 600 had the smooth surface and inhibited the formation of apatite layer in SBF. These as-prepared hybrid monoliths can be used as a good candidate of implant and scaffold for highly efficient bone tissue regeneration.

  9. Method of monolithic module assembly

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-01-01

    Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  10. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.; Matthias, Sabrina

    2014-10-01

    Beam expanding is a common task, where Galileo telescopes are preferred. However researches and customers have found limitations when using these systems. A new monolithical solution which is based on the usage of only one aspherical component will be presented. It will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Insights will be given how aspherical beam expanding systems will help using larger incoming beams and reducing the overall length of such a system. Additionally an add-on element for divergence and wavelength adaption will be presented.

  11. Allyl-silica Hybrid Monoliths For Chromatographic Application

    NASA Astrophysics Data System (ADS)

    Guo, Wenjuan

    Column technology continues to be the most investigated topics in the separation world, since the column is the place where the chromatographic separation happens, making it the heart of the separation system. Allyl-silica hybrid monolithic material has been exploited as support material and potential stationary phases for liquid chromatography; the stationary phase anchored to the silica surface by Si-C bond, which is more pH stable than traditional stationary phase. First, nuclear magnetic resonance spectroscopy has been used to study the sol in the synthesis of allyl-silica hybrid monoliths. Allyl-trimethoxysilane (allyl-TrMOS), dimethyldimethoxysilane (DMDMOS) and tetramethoxysilane (TMOS) have been served as co-precursors in the sol-gel synthesis of organo-silica hybrid monolithic columns for liquid chromatography (LC). 29Si nuclear magnetic resonance (NMR) and 1H NMR spectroscopy were employed to monitor reaction profiles for the acid-catalyzed hydrolysis and initial condensation reactions of the individual precursor and the hybrid system. 29Si-NMR has also been used to identify different silane species formed during the reactions. The overall hydrolysis rate has been found to follow the trend DMDMOS > allyl-TrMOS > TMOS, if each precursor is reacted individually (homo-polymerization). Precursors show different hydrolysis rate when reacted together in the hybrid system than they are reacted individually. Cross-condensation products of TMOS and DMDMOS (QD) arise about 10 minutes of initiation of the reaction. The allyl-silica monolithic columns for capillary liquid chromatography can only be prepared in capillaries with 50 im internal diameter with acceptable performance. One of the most prominent problems related to the synthesis of silica monolithic structures is the volume shrinkage. The synthesis of allylfunctionalized silica hybrid monolithic structures has been studied in an attempt to reduce the volume shrinkage during aging, drying and heat treatment

  12. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water.

  13. Rationally engineered synthetic coculture for improved biomass and product formation.

    PubMed

    Santala, Suvi; Karp, Matti; Santala, Ville

    2014-01-01

    In microbial ecosystems, bacteria are dependent on dynamic interspecific interactions related to carbon and energy flow. Substrates and end-metabolites are rapidly converted to other compounds, which protects the community from high concentrations of inhibitory molecules. In biotechnological applications, pure cultures are preferred because of the more straight-forward metabolic engineering and bioprocess control. However, the accumulation of unwanted side products can limit the cell growth and process efficiency. In this study, a rationally engineered coculture with a carbon channeling system was constructed using two well-characterized model strains Escherichia coli K12 and Acinetobacter baylyi ADP1. The directed carbon flow resulted in efficient acetate removal, and the coculture showed symbiotic nature in terms of substrate utilization and growth. Recombinant protein production was used as a proof-of-principle example to demonstrate the coculture utility and the effects on product formation. As a result, the biomass and recombinant protein titers of E. coli were enhanced in both minimal and rich medium simple batch cocultures. Finally, harnessing both the strains to the production resulted in enhanced recombinant protein titers. The study demonstrates the potential of rationally engineered cocultures for synthetic biology applications.

  14. Nursing Doctorates in Brazil: research formation and theses production

    PubMed Central

    Scochi, Carmen Gracinda Silvan; Gelbcke, Francine Lima; Ferreira, Márcia de Assunção; Lima, Maria Alice Dias da Silva; Padilha, Katia Grillo; Padovani, Nátali Artal; Munari, Denize Bouttelet

    2015-01-01

    OBJECTIVE: to analyze the formation of nursing doctorates in Brazil, from theses production, disciplines and other strategies focusing on research offered by courses. METHOD: a descriptive and analytical study of the performance of 18 doctoral courses in nursing, running from 1982 to 2010, and defended their theses between 2010-2012. RESULTS: 502 theses were defended in this period, most linked to the online research process of health and nursing care. There are gaps in the knowledge of theoretical and philosophical foundations of care, nursing history and ethics. There are also weaknesses in the methodological design of the theses, with a predominance of descriptive and/or exploratory studies. This was consistent with international standards set with regards to the proposition of research of disciplines and complementary strategies in forming the doctorate. CONCLUSION: despite the efforts and advances in research formation, it is essential to expand to more robust research designs with a greater impact on production knowledge that is incorporated into practice. PMID:26312630

  15. Formation of organochlorine by-products in bleached laundry.

    PubMed

    Leri, Alessandra C; Anthony, Laura N

    2013-02-01

    Laundering fabrics with chlorine bleach plays a role in health and hygiene as well as aesthetics. However, laundry bleaching may create chlorinated by-products with potentially adverse human health effects. Studies have shown that toxic chlorinated gases are produced in the headspace of washing machines when hypochlorite-containing bleach is used. Laundry bleaching has also been implicated in contributing dissolved organochlorine to municipal wastewater. However, there have been no reports of organochlorines produced and retained in fabric as a result of laundry bleaching. We have used a chlorine-specific X-ray spectroscopic analysis to demonstrate the formation of organochlorine by-products in cotton fabrics laundered with chlorine bleach under typical household conditions. Organochlorine formation increases at higher wash temperature. At least two pools of organochlorine are produced in bleached fabric: a labile fraction that diminishes over several months of storage time as well as a more stable fraction that persists after more than 1 year. Our results also suggest that residual hypochlorite remains in fabric after laundering with bleach, presenting the possibility of direct and sustained dermal contact with reactive chlorine. This study provides a first step toward identifying a new risk factor for elevated organochlorine body burdens in humans.

  16. Monolithic molecularly imprinted cryogel for lysozyme recognition.

    PubMed

    Rabieizadeh, Mohammadmahdi; Kashefimofrad, Seyed Mohammadreza; Naeimpoor, Fereshteh

    2014-10-01

    The application of molecularly imprinted polymers in the selective adsorption of macromolecules such as proteins by monolithic protein-imprinted columns requires a macroporous structure, which can be provided by cryogelation at low temperature in which the formation of ice crystals gives a porous structure to the molecularly imprinted polymer. In this study, we applied this technique to synthesize lysozyme-imprinted polyacrylamide cryogels containing 8% w/v of total monomers and 0.3% w/v of lysozyme. The synthesized cryogel was sponge-like and elastic with very fast swelling and reshaping properties, showing a swelling ratio of 24.5 ± 3 and gel fraction yield of about 72%. It showed an imprinting effect of 1.58 and a separation factor of 1.37 for cytochrome c as the competing protein. Adsorption studies on the cryogel revealed that it follows the Langmuir isotherm, with a maximum theoretical adsorption capacity of 36.3 mg lysozyme per gram of cryogel. Additionally, it was shown that a salt-free rebinding solution at low flow rate and pH = 7.0 is favorable for lysozyme rebinding. This kind of monolithic column promises a wide range of application in separation of various biomolecules due to its preparation simplicity, good rebinding characteristics, and macroporosity.

  17. Genistein inhibits advanced glycation end product formation by trapping methylglyoxal.

    PubMed

    Lv, Lishuang; Shao, Xi; Chen, Huadong; Ho, Chi-Tang; Sang, Shengmin

    2011-04-18

    Methylglyoxal (MGO) is a highly reactive endogenous metabolite derived from several nonenzymatic and enzymatic reactions, and identified as a well-known precursor of advanced glycation end products (AGEs). In the present study, genistein, a naturally occurring isoflavone derived from soy products, demonstrated significant trapping effects of MGO and consequently formed mono- and di-MGO adducts under physiological conditions (pH 7.4, 37 °C). More than 80.0% of MGO was trapped within 4 h, and the trapping efficiency could be up to 97.7% at 24 h. The reaction adducts formed from genistein and MGO under different ratios were analyzed using LC/MS. We also successfully purified and identified the major mono- and di-MGO conjugated adducts of genistein. The NMR data showed that positions 6 and 8 of the A ring of genistein were the major active sites for trapping MGO. We further demonstrated that genistein could effectively inhibit the formation of AGEs in the human serum albumin (HSA)-MGO assay. Two mono-MGO adducts and one di-MGO adduct of genistein were detected in this assay using LC/MS. The di-MGO adduct of genistein became the dominant reaction product during prolonged incubation. Results from this study, as well as our previous findings on (-)-epigallocatechin 3-gallate (EGCG), phloridzin and phloretin, indicate that dietary flavonoids that have the same A ring structure as genistein, EGCG, phloridzin, and phloretin may have the potential to inhibit the formation of AGEs by trapping reactive dicarbonyl species.

  18. Monolithic blue upconversion fiber laser

    NASA Astrophysics Data System (ADS)

    Gaebler, Volker; Eichler, Hans J.

    2002-06-01

    We report a monolithic low threshold 482nm Tm:ZBLAN upconversion fiber laser. The laser cavity consists of a directly coated single-mode fluoride fiber. The vapor deposit coatings significantly reduce the coupling losses and are suitable to be pumped by laser diodes. The laser operation and threshold characteristics have been investigated. The output stability and beam quality was tested.

  19. Monolithic fiber optic sensor assembly

    SciTech Connect

    Sanders, Scott

    2015-02-10

    A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

  20. Protective Skins for Aerogel Monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

    2007-01-01

    A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

  1. Ethanol production by thermophilic bacteria: metabolic control of end product formation in Thermoanaerobium brockii

    SciTech Connect

    Ben-Bassat, A.; Lamed, R.; Zeikus, J.G.

    1981-04-01

    Specific changes in the chemical and microbial composition fof Thermoanaerobium brockii fermentations were compared and related to alterations of process rates, end product yields, and growth parameters. Fermentation of starch as compared with glucose was associated with significant decreases in growth rate and intracellular fructose-1,6-bisphosphate concentration and with a dramatic increase in the ethanols/lactate product ratio. Glucose or pyruvate fermentation in the presence of acetone was correlated with increased substrate consumption, growth, acetate yield, and quantitative reduction of acetone to isopropanol in lieu of normal reduced fermentation products. Glucose fermentation in the presence of exogenous hydrogen was associated with inhibition of endogenous H/sub 2/ production. The effects of exogenous hydrogen on glucose fermentation were totally reversed by the addition of acetone. Glucose fermentation in coculture with Methanobacterium thermoautotrophicum correlated with increased growth, acetate yield, and the formation of methane in lieu of monoculture reduced products.

  2. Monolithic silica sorbents for the separation of diastereomers by means of simulated moving bed chromatography.

    PubMed

    Schulte, M; Dingenen, J

    2001-07-20

    Monolithic silica sorbents with a dual pore system can be used in preparative chromatography for the separation of diastereomers. They exhibit some special features, which allows them to be operated at high linear velocities due to their reduced pressure drop and fast diffusion kinetics. Especially in the continuous set-up of simulated moving bed chromatography monolithic sorbents show high productivities, which make them well suited in pharmaceutical drug development for the production of pure isomers.

  3. Transparent monolithic metal ion containing nanophase aerogels

    SciTech Connect

    Risen, W. M., Jr.; Hu, X.; Ji, S.; Littrell, K.

    1999-12-01

    The formation of monolithic and transparent transition metal containing aerogels has been achieved through cooperative interactions of high molecular weight functionalized carbohydrates and silica precursors, which strongly influence the kinetics of gelation. After initial gelation, subsequent modification of the ligating character of the system, coordination of the group VIII metal ions, and supercritical extraction afford the aerogels. The structures at the nanophase level have been probed by photon and electron transmission and neutron scattering techniques to help elucidate the basis for structural integrity together with the small entity sizes that permit transparency in the visible range. They also help with understanding the chemical reactivities of the metal-containing sites in these very high surface area materials. These results are discussed in connection with new reaction studies.

  4. Mineral formation during production of highly saline geothermal fluids

    NASA Astrophysics Data System (ADS)

    Regenspurg, S.; Naumann, R.; Feldbusch, E.; Wagner, S.; Saadat, A.

    2012-04-01

    Geothermal solutions produced from deep wells are often highly saline and of complex composition impeding exact predictions of fluid-mineral interactions. At constant (high) temperature and flow conditions during plant operation, only little precipitation would be expected. However, during the initial phase of the operation of a geothermal plant, the testing of equipment components such as pumps and valves prevents these constant fluid flow conditions. Moreover, fluid temperatures are still relatively low and vary strongly at this stage. These inhomogeneous conditions result in the precipitation of a wide range of minerals. The analysis of solutions composition as well as of the mineral precipitates during this initial testing phase represents a unique in-situ experiment allowing understanding the mineral formation from complex solutions under a wide range of temperatures. This experiment was possible at the geothermal in-situ laboratory in Groß Schönebeck (North German Basin). At this site, hot fluid (150 °C at 4400 m depth) is pumped out of a production well to the surface where it passes the above ground installation (e.g. 1 µm filter bags) before it would be re-injected into a second (injection) well. The temperature of the produced fluid varied between 10 and 100°C due to numerous turning on and shutdown phases. Fluid and filter residues have been analyzed during several cycles. In the solid phase, almost no minerals of the reservoir sandstone have been identified. Instead, several compunds have been found which precipitated directly from the solution. One group, dominated mainly by barite (BaSO4), formed as consequence of the cooling effect, which affects strongly the solubility product and results in mineral precipitation. The other group of minerals (such as magnetite or several lead minerals) form due to changes in redox conditions. These changes occur possibly in the region close to the production pump, where a strong magnetic field and highly

  5. Titanium-scaffolded organic-monolithic stationary phases for ultra-high-pressure liquid chromatography.

    PubMed

    Vonk, Rudy J; Vaast, Axel; Eeltink, Sebastiaan; Schoenmakers, Peter J

    2014-09-12

    Organic-polymer monoliths with overall dimensions larger than one millimetre are prone to rupture - either within the monolith itself or between the monoliths and the containing wall - due to the inevitable shrinkage accompanying the formation of a cross-linked polymeric network. This problem has been addressed by creating titanium-scaffolded poly(styrene-co-divinylbenzene) (S-co-DVB) monoliths. Titanium-scaffolded monoliths were successfully used in liquid chromatography at very high pressures (up to 80MPa) and using gradients spanning the full range of water-acetonitrile compositions (0 to 100%). The kinetic-performance of (50-mm long) titanium-scaffolded monoliths was compared to that of similar monolith created in 1-mm i.d. glass-lined tubing at pressures up to 50MPa. The peak capacities obtained with the titanium-scaffolded column was about 30% lower. An increased Eddy-diffusion, due to the pillar-structure, and a decreased permeability are thought to be the main reasons for this reduced kinetic-performance. No decrease in performance was observed when the titanium-scaffolded columns were operated at pressures of 80MPa for up to 12h. The column-to-column repeatability (n=5) was acceptable in terms of observed peak widths at half heights (RSD ca. 10%) The run-to-run repeatability (n=135) in terms of retention times and peak widths at half height were found to be good. Titanium-scaffolded columns coupled in series up to a combined length of (200mm) were used for the analyses of a complex Escherichia coli protein sample. Our experiments demonstrate that columns based on titanium-scaffolded organic-polymer monolith can be operated under strenuous conditions without loss in performance. The titanium-scaffolded approach makes it feasible to create organic-polymer monoliths in wide-bore columns with accurate temperature control.

  6. Monolithic pattern-sensitive detector

    DOEpatents

    Berger, Kurt W.

    2000-01-01

    Extreme ultraviolet light (EUV) is detected using a precisely defined reference pattern formed over a shallow junction photodiode. The reference pattern is formed in an EUV absorber preferably comprising nickel or other material having EUV- and other spectral region attenuating characteristics. An EUV-transmissive energy filter is disposed between a passivation oxide layer of the photodiode and the EUV transmissive energy filter. The device is monolithically formed to provide robustness and compactness.

  7. Monolithic Fuel Fabrication Process Development

    SciTech Connect

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  8. Reduced by-product formation and modified oxygen availability improve itaconic acid production in Aspergillus niger.

    PubMed

    Li, An; Pfelzer, Nina; Zuijderwijk, Robbert; Brickwedde, Anja; van Zeijl, Cora; Punt, Peter

    2013-05-01

    Aspergillus niger has an extraordinary potential to produce organic acids as proven by its application in industrial citric acid production. Previously, it was shown that expression of the cis-aconitate decarboxylase gene (cadA) from Aspergillus terreus converted A. niger into an itaconic acid producer (Li et al., Fungal Genet Bio 48: 602-611, 2011). After some initial steps in production optimization in the previous research (Li et al., BMC biotechnol 12: 57, 2012), this research aims at modifying host strains and fermentation conditions to further improve itaconic acid production. Expression of two previously identified A. terreus genes encoding putative organic acid transporters (mttA, mfsA) increased itaconic acid production in an A. niger cis-aconitate decarboxylase expressing strain. Surprisingly, the production did not increase further when both transporters were expressed together. Meanwhile, oxalic acid was accumulated as a by-product in the culture of mfsA transformants. In order to further increase itaconic acid production and eliminate by-product formation, the non-acidifying strain D15#26 and the oxaloacetate acetylhydrolase (oahA) deletion strain AB 1.13 ∆oahA #76 have been analyzed for itaconic acid production. Whereas cadA expression in AB 1.13 ∆oahA #76 resulted in higher itaconic acid production than strain CAD 10.1, this was not the case in strain D15#26. As expected, oxalic acid production was eliminated in both strains. In a further attempt to increase itaconic acid levels, an improved basal citric acid-producing strain, N201, was used for cadA expression. A selected transformant (N201CAD) produced more itaconic acid than strain CAD 10.1, derived from A. niger strain AB1.13. Subsequently, we have focused on the influence of dissolved oxygen (D.O.) on itaconic acid production. Interestingly, reduced D.O. levels (10-25 %) increased itaconic acid production using strain N201 CAD. Similar results were obtained in strain AB 1.13 CAD + HBD2

  9. Graphene-supported metal oxide monolith

    DOEpatents

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  10. Minimization of the formation of disinfection by-products.

    PubMed

    Badawy, Mohamed I; Gad-Allah, Tarek A; Ali, Mohamed E M; Yoon, Yeoman

    2012-09-01

    The drinking water industry is required to minimize DBPs levels while ensuring adequate disinfection. In this study, efficient and appropriate treatment scheme for the reduction of disinfection by-product (DBPs) formation in drinking water containing natural organic matter has been established. This was carried out by the investigation of different treatment schemes consisting of enhanced coagulation, sedimentation, disinfection by using chlorine dioxide/ozone, filtration by sand filter, or granular activated carbon (GAC). Bench scale treatment schemes were applied on actual samples from different selected sites to identify the best conditions for the treatment of water. Samples were collected from effluent of each step in the treatment train in order to analyze pH, UV absorbance at 254 nm (UVA(254)), specific UV absorbance at 254 nm (SUVA(254)), dissolved organic carbon (DOC), haloacetic acids (HAAs) and trihalomethanes (THMs). The obtained results indicated that using pre-ozonation/enhanced coagulation/activated carbon filtration treatment train appears to be the most effective method for reducing DBPs precursors in drinking water treatment.

  11. Formation of alteration products during dissolution of vitrified ILW in a high-pH calcium-rich solution

    NASA Astrophysics Data System (ADS)

    Utton, C. A.; Hand, R. J.; Hyatt, N. C.; Swanton, S. W.; Williams, S. J.

    2013-11-01

    To simulate the possible disposition of a vitrified intermediate-level waste (ILW) in a cementitious environment within a geological disposal facility (GDF), the durability of a laboratory simulant ILW vitrified in a borosilicate glass in a saturated Ca(OH)2 solution (pH ˜12.5) was measured. Both a low surface area to volume (SA/V) ratio (˜10 m-1) Materials Characterisation Center test 1 (MCC-1) and a high SA/V ratio (˜10,000 m-1) product consistency test type B (PCT-B) were used at 50 °C for up to 170 days. The formation of alteration layers and products was followed. The surfaces of the monoliths were analysed using SEM/EDX and showed the formation of magnesium-rich precipitates and distinct calcium silicate hydrate (CSH) precipitates. Cross sections showed the development of a calcium-rich alteration layer, which was observed from 14 days. The altered layer was up to 5 μm thick after 170 days and showed accumulation of zirconium, iron and magnesium and to a lesser extent aluminium, along with calcium and silicon. Based on comparison of the rate data, it is suggested that the presence of this layer may offer some protection to the underlying glass. However, the high SA/V ratio experiments showed resumed alteration after 56 days, indicating that the altered layer may not be protective in the long term (under accelerated conditions). The formation of a magnesium-containing smectite clay (likely saponite) in addition to CSH(II), a jennite-like CSH phase, were identified in the high SA/V experiment by X-ray diffraction after 170 days. These results suggest that calcium and magnesium have important roles in both the long and shorter-term durability of vitrified wastes exposed to high pH. This is higher than the value of 63 kJ mol-1 reported by Abraitis [21]. This appears to originate from a mathematical error in calculating the activation energy, given the underlying data reported, reproduced here in Table 3.

  12. Engineering a Hyperthermophilic Archaeon for Temperature-Dependent Product Formation

    SciTech Connect

    Basen, M; Sun, JS; Adams, MWW

    2012-02-24

    Microorganisms growing near the boiling point have enormous biotechnological potential but only recently have molecular engineering tools become available for them. We have engineered the hyperthermophilic archaeon Pyrococcus furiosus, which grows optimally at 100 degrees C, to switch its end products of fermentation in a temperature-controlled fashion without the need for chemical inducers. The recombinant strain (LAC) expresses a gene (ldh) encoding lactate dehydrogenase from the moderately thermophilic Caldicellulosiruptor bescii (optimal growth temperature [T-opt] of 78 degrees C) controlled by a "cold shock" promoter that is upregulated when cells are transferred from 98 degrees C to 72 degrees C. At 98 degrees C, the LAC strain fermented sugar to produce acetate and hydrogen as end products, and lactate was not detected. When the LAC strain was grown at 72 degrees C, up to 3 mM lactate was produced instead. Expression of a gene from a moderately thermophilic bacterium in a hyperthermophilic archaeon at temperatures at which the hyperthermophile has low metabolic activity provides a new perspective to engineering microorganisms for bioproduct and biofuel formation. IMPORTANCE Extremely thermostable enzymes from microorganisms that grow near or above the boiling point of water are already used in biotechnology. However, the use of hyperthermophilic microorganisms themselves for biotechnological applications has been limited by the lack of their genetic accessibility. Recently, a genetic system for Pyrococcus furiosus, which grows optimally near 100 degrees C, was developed in our laboratory. In this study, we present the first heterologous protein expression system for a microorganism that grows optimally at 100 degrees C, a first step towards the potential expression of genes involved in biomass degradation or biofuel production in hyperthermophiles. Moreover, we developed the first system for specific gene induction in P. furiosus. As the cold shock promoter

  13. Monolithic microwave integrated circuit water vapor radiometer

    NASA Technical Reports Server (NTRS)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  14. Single step plasmid DNA purification using methacrylate monolith bearing combination of ion-exchange and hydrophobic groups.

    PubMed

    Smrekar, Vida; Smrekar, Franc; Strancar, Aleš; Podgornik, Aleš

    2013-02-08

    Purification of high quantities of human grade plasmid DNA is one of the most intensive production steps. Because of that several methods have been proposed, among them also chromatographic purification using methacrylate monoliths. Recently, a process comprising the combination of hydrophobic interaction (HIC) monolith and ion-exchange monolith was developed. In this work both chemistries were tried to be introduced on a single monolith. Methacrylate monoliths bearing octylamine groups, combination of butyl (C4) grafted methacrylate groups and diethylaminoethyl (DEAE) groups as well as grafted chains bearing both C4 and DEAE groups were prepared. All monoliths were investigated for their ionic and protein capacity and compared to conventional epoxy, C4, and DEAE methacrylate monoliths. Octylamine monolith and monolith bearing combination of C4 grafted methacrylate groups and DEAE groups were found to be the most promising candidates and were further tested for plasmid DNA (pDNA) dynamic binding capacity under ion-exchange (IEX) and HIC binding conditions and ability to separate open circular (OC) from supercoiled (SC) pDNA forms and RNA from pDNA. Since monolith bearing combination of grafted C4 methacrylate groups and DEAE groups was superior in all three tested features, exhibiting pDNA dynamic binding capacity of 4.7 mg/ml under IEX conditions and 2.1mg/ml under HIC conditions, it was used for the development of a single step purification method and tested with pure pDNA as well as with cell lysate. Developed method removed over 99% of RNA, host cell proteins (HCP) and genomic DNA (gDNA) demonstrating capacity to purify around 1.5mg of pDNA/ml of monolith from cell lysate.

  15. Monolithically integrated absolute frequency comb laser system

    SciTech Connect

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  16. Monolithic CMOS imaging x-ray spectrometers

    NASA Astrophysics Data System (ADS)

    Kenter, Almus; Kraft, Ralph; Gauron, Thomas; Murray, Stephen S.

    2014-07-01

    The Smithsonian Astrophysical Observatory (SAO) in collaboration with SRI/Sarnoff is developing monolithic CMOS detectors optimized for x-ray astronomy. The goal of this multi-year program is to produce CMOS x-ray imaging spectrometers that are Fano noise limited over the 0.1-10keV energy band while incorporating the many benefits of CMOS technology. These benefits include: low power consumption, radiation "hardness", high levels of integration, and very high read rates. Small format test devices from a previous wafer fabrication run (2011-2012) have recently been back-thinned and tested for response below 1keV. These devices perform as expected in regards to dark current, read noise, spectral response and Quantum Efficiency (QE). We demonstrate that running these devices at rates ~> 1Mpix/second eliminates the need for cooling as shot noise from any dark current is greatly mitigated. The test devices were fabricated on 15μm, high resistivity custom (~30kΩ-cm) epitaxial silicon and have a 16 by 192 pixel format. They incorporate 16μm pitch, 6 Transistor Pinned Photo Diode (6TPPD) pixels which have ~40μV/electron sensitivity and a highly parallel analog CDS signal chain. Newer, improved, lower noise detectors have just been fabricated (October 2013). These new detectors are fabricated on 9μm epitaxial silicon and have a 1k by 1k format. They incorporate similar 16μm pitch, 6TPPD pixels but have ~ 50% higher sensitivity and much (3×) lower read noise. These new detectors have undergone preliminary testing for functionality in Front Illuminated (FI) form and are presently being prepared for back thinning and packaging. Monolithic CMOS devices such as these, would be ideal candidate detectors for the focal planes of Solar, planetary and other space-borne x-ray astronomy missions. The high through-put, low noise and excellent low energy response, provide high dynamic range and good time resolution; bright, time varying x-ray features could be temporally and

  17. Compact monolithic capacitive discharge unit

    DOEpatents

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  18. Nanosecond monolithic CMOS readout cell

    DOEpatents

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  19. Nitrate photochemistry in NaY zeolite: product formation and product stability under different environmental conditions.

    PubMed

    Gankanda, Aruni; Grassian, Vicki H

    2013-03-14

    In the atmosphere, mineral dust particles are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides (N2O5, HNO3, NO3, and NO2). Nitrate ions associated with mineral dust particles can undergo further reactions including those initiated by solar radiation. Although nitrate photochemistry in aqueous media is fairly well studied, much less is known about the photochemistry of nitrate adsorbed on mineral dust particles. In this study, the photochemistry of nitrate from HNO3 adsorption in NaY zeolite under different environmental conditions has been investigated using transmission FTIR spectroscopy. NaY zeolite is used as a model zeolite for studying reactions that can occur in confined space such as those found in porous materials including naturally occurring zeolites and clays. Upon nitrate photolysis under dry conditions (relative humidity, RH, < 1%), surface nitrite is formed as the major adsorbed product. Although nitrite has been proposed as a product in the photochemistry of nitrate adsorbed on metal oxide particle surfaces, such as on alumina, it has not been previously detected. The stability of adsorbed nitrite in NaY is attributed to the confined three-dimensional structure of the porous zeolite, which contains a charge compensating cation that can stabilize the nitrite ion product. Besides adsorbed nitrite, small amounts of gas phase nitrogen-containing products are observed as well including NO2, NO, and N2O at long irradiation times. The amount of nitrite formed via nitrate photochemistry decreases with increasing relative humidity, whereas gas phase NO and N2O become the only detectable products. Gas-phase NO2 does not observe at RH > 1%. In the presence of gas phase ammonia, ammonium nitrate is formed in NaY zeolite. Photochemistry of ammonium nitrate yields gas phase N2O as the sole gas phase product. Evidence for an NH2 intermediate in the formation of N2O is identified with FTIR spectroscopy for HNO3 adsorption and

  20. CCN production by new particle formation in the free troposphere

    NASA Astrophysics Data System (ADS)

    Rose, Clémence; Sellegri, Karine; Moreno, Isabel; Velarde, Fernando; Ramonet, Michel; Weinhold, Kay; Krejci, Radovan; Andrade, Marcos; Wiedensohler, Alfred; Ginot, Patrick; Laj, Paolo

    2017-01-01

    Global models predict that new particle formation (NPF) is, in some environments, responsible for a substantial fraction of the total atmospheric particle number concentration and subsequently contributes significantly to cloud condensation nuclei (CCN) concentrations. NPF events were frequently observed at the highest atmospheric observatory in the world, on Chacaltaya (5240 m a.s.l.), Bolivia. The present study focuses on the impact of NPF on CCN population. Neutral cluster and Air Ion Spectrometer and mobility particle size spectrometer measurements were simultaneously used to follow the growth of particles from cluster sizes down to ˜ 2 nm up to CCN threshold sizes set to 50, 80 and 100 nm. Using measurements performed between 1 January and 31 December 2012, we found that 61 % of the 94 analysed events showed a clear particle growth and significant enhancement of the CCN-relevant particle number concentration. We evaluated the contribution of NPF, relative to the transport and growth of pre-existing particles, to CCN size. The averaged production of 50 nm particles during those events was 5072, and 1481 cm-3 for 100 nm particles, with a larger contribution of NPF compared to transport, especially during the wet season. The data set was further segregated into boundary layer (BL) and free troposphere (FT) conditions at the site. The NPF frequency of occurrence was higher in the BL (48 %) compared to the FT (39 %). Particle condensational growth was more frequently observed for events initiated in the FT, but on average faster for those initiated in the BL, when the amount of condensable species was most probably larger. As a result, the potential to form new CCN was higher for events initiated in the BL (67 % against 53 % in the FT). In contrast, higher CCN number concentration increases were found when the NPF process initially occurred in the FT, under less polluted conditions. This work highlights the competition between particle growth and the removal of

  1. Formation and Occurrence of Disinfection By-Products

    EPA Science Inventory

    Disinfection by-products (DBPs) are formed when disinfectants such as chlorine, ozone, chlorine dioxide, or chloramines react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. There is concern about D...

  2. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.

    2014-02-01

    In complex laser systems, such as those for material processing, and in basically all laboratory applications passive optical components are indispensable. Matching beam diameters is a common task, where Galileo type telescopes are preferred for beam expansion. Nevertheless researches and customers have found various limitations when using these systems. Some of them are the complicated adjustment, very small diameter for the incoming beam (1/e2), fixed and non-modifiable magnifications. Above that, diffraction-limitation is only assured within the optical design and not for the real world setup of the beam expanding system. Therefore, we will discuss limitations of currently used beam expanding systems to some extent. We will then present a new monolithical solution, which is based on the usage of only one aspherical component. It will be shown theoretically how the beam quality can be significantly improved by using aspherical lenses. As it is in the nature of things aspheres are working diffraction limited in the design, it will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Data of the culminated wavefront error will be presented. Last but not least insights will be given how beam expanding systems based on aspheres will help to use larger incoming beams and to reduce the overall length of such a system.

  3. Design and Testing of Prototypic Elements Containing Monolithic Fuel

    SciTech Connect

    N.E. Woolstenhulme; M.K. Meyer; D.M. Wachs

    2011-10-01

    The US fuel development team has performed numerous irradiation tests on small to medium sized specimens containing low enriched uranium fuel designs. The team is now focused on qualification and demonstration of the uranium-molybdenum Base Monolithic Design and has entered the next generation of testing with the design and irradiation of prototypic elements which contain this fuel. The designs of fuel elements containing monolithic fuel, such as AFIP-7 (which is currently under irradiation) and RERTR-FE (which is currently under fabrication), are appropriate progressions relative to the technology life cycle. The culmination of this testing program will occur with the design, fabrication, and irradiation of demonstration products to include the base fuel demonstration and design demonstration experiments. Future plans show that design, fabrication, and testing activities will apply the rigor needed for a demonstration campaign.

  4. Development of stable monolithic wide-field Michelson interferometers

    NASA Astrophysics Data System (ADS)

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-01

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10-6/° C near 550nm, which corresponds to ˜800m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  5. Development of stable monolithic wide-field Michelson interferometers.

    PubMed

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-20

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10(-6)/°C near 550 nm, which corresponds to ∼800 m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  6. Microfluidic devices and methods including porous polymer monoliths

    DOEpatents

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  7. Microfluidic devices and methods including porous polymer monoliths

    SciTech Connect

    Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

    2015-12-01

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  8. Method and apparatus for production of subsea hydrocarbon formations

    DOEpatents

    Blandford, J.W.

    1995-01-17

    A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external flotation tanks located below the water surface. The surface buoy is secured to the sea bed by one or more tendons which are anchored to a foundation with piles imbedded in the sea bed. The system accommodates multiple versions on the surface buoy configuration. 20 figures.

  9. Method and apparatus for production of subsea hydrocarbon formations

    DOEpatents

    Blandford, Joseph W.

    1995-01-01

    A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external floatation tanks located below the water surface. The surface buoy is secured to the seabed by one or more tendons which are anchored to a foundation with piles imbedded in the seabed. The system accommodates multiple versions on the surface buoy configuration.

  10. Effect of Silica on High-Temperature Interfacial Phenomena of Monolithic Refractories with Al Alloy

    NASA Astrophysics Data System (ADS)

    Koshy, Pramod; Gupta, Sushil; Sahajwalla, Veena; Edwards, Phil

    2008-04-01

    An experimental study was conducted to study the interfacial phenomena between monolithic refractories and Al alloy at 1250 °C. Dynamic contact angles of monolithic substrates with varying silica levels were measured using the sessile drop technique, while phases present in the preheated monolithic samples and interfacial reaction products were characterized using X-ray diffraction (XRD) and an electron probe microanalyzer (EPMA). The contact angles in the Al alloy/silica system were found to change much more rapidly as compared to that of the alloy/alumina system, clearly demonstrating the high wetting tendency of silica. Under the tested conditions, the corundum phase forms at the interface while Mg was found to vaporize from the alloy and accumulate at the bottom of the monolithic substrate. Both these phenomena are shown to influence the intensity of contact angle variations with time and, thereby, the wetting behavior of monolithic substrates. Based on dynamic contact angles and equilibrium calculations, monolithic refractories are further classified into three groups, such that the wetting characteristics of those with compositions in the ranges of 0 to 25 pct, 25 to 45 pct, and >45 pct silica were shown to be dictated by the presence of corundum, mullite, and free silica, respectively, as the predominant phase.

  11. Microbial methanol formation: A major end product of pectin metabolism

    SciTech Connect

    Schink, B.; Zeikus, J.G.

    1980-01-01

    Various pectinolytic strains of Clostridium, Erwinia, and Pseudomonas species produced methanol as a major end product during growth on pectin but not on glucose of polygalacturonic acid. Pectin metabolism of Clostridium butyricum strain 4PI correlated with a final product concentration of 16 mM at the end of growth, and a 1:1 stoichiometry for methanol production and percent initial substrate methoxylation. Growth on pectin was associated with high activity of pectin methylesterase and the absence of methanol consumption. The ecological significance of pectin metabolism and the establishment of microbial methylotrophic metabolism in nature is discussed.

  12. Gravitationally induced particle production and its impact on structure formation

    NASA Astrophysics Data System (ADS)

    Nunes, Rafael C.

    2016-08-01

    In this paper we investigate the influence of a continuous particles creation processes on the linear and nonlinear matter clustering, and its consequences on the weak lensing effect induced by structure formation. We study the line of sight behavior of the contribution to the bispectrum signal at a given angular multipole l, showing that the scale where the nonlinear growth overcomes the linear effect depends strongly of particles creation rate.

  13. Monolithic cells for solar fuels.

    PubMed

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-07

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  14. Advances in monolithic ferroelectric uncooled IRFPA technology

    NASA Astrophysics Data System (ADS)

    Hanson, Charles M.; Beratan, Howard R.; Belcher, James F.; Udayakumar, K. R.; Soch, Kevin L.

    1998-07-01

    The success of uncooled IR imaging at Raytheon has awakened a new view of the potential of thermal imaging. Once relegated to only expensive military platforms, occasionally to civilian platforms, and envisioned for individual soldiers, thermal imaging is now affordable for police cars, commercial surveillance, driving aids, and a variety of other industrial and consumer applications. System prices are as low as $8000, and swelling production volume will soon drive prices substantially lower. The impetus for further development is performance. The hybrid barium strontium titanate (BST) detectors currently in production have limited potential for improved sensitivity, and their MTF is suppressed at high frequencies. Microbolometer arrays in development at Raytheon have demonstrated performance superior to hybrid detectors. However, microbolometer technology lacks a mature, low-cost system technology and an abundance of deployable system implementations. Thin-film ferroelectric (TFFE) detectors have all the performance potential of microbolometers, and arguably more. They are also compatible with numerous fielded and planned system implementations. Like a microbolometer, the TFFE detector is monolithic; i.e., the detector material is deposited directly on the readout IC rather than being bump bonded to it. Initial imaging arrays of 240 X 320 pixels have been produced, demonstrating the feasibility of the technology.

  15. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    NASA Astrophysics Data System (ADS)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  16. Detailed characterization of the kinetic performance of first and second generation silica monolithic columns for reversed-phase chromatography separations.

    PubMed

    Cabooter, Deirdre; Broeckhoven, Ken; Sterken, Roman; Vanmessen, Alison; Vandendael, Isabelle; Nakanishi, Kazuki; Deridder, Sander; Desmet, Gert

    2014-01-17

    The kinetic performance of commercially available first generation and prototype second generation silica monoliths has been investigated for 2.0mm and 3.0-3.2mm inner diameter columns. It is demonstrated that the altered sol-gel process employed for the production of second generation monoliths results in structures with a smaller characteristic size leading to an improved peak shape and higher efficiencies. The permeability of the columns however, decreases significantly due to the smaller throughpore and skeleton sizes. Scanning electron microscopy pictures suggest the first generation monoliths have cylindrical skeleton branches, whereas the second generation monoliths rather have skeleton branches that resemble a single chain of spherical globules. Using recently established correlations for the flow resistance of cylindrical and globule chain type monolithic structures, it is demonstrated that the higher flow resistance of the second generation monoliths can be entirely attributed to their smaller skeleton sizes, which is also evident from the external porosity that is largely the same for both monolith generations (ɛe∼0.65). The recorded van Deemter plots show a clear improvement in efficiency for the second generation monoliths (minimal plate heights of 13.6-14.1μm for the first and 6.5-8.2μm for the second generation, when assessing the plate count using the Foley-Dorsey method). The corresponding kinetic plots, however, indicate that the much reduced permeability of the second generation monoliths results in kinetic performances (time needed to achieve a given efficiency) which are only better than those of the first generation for plate counts up to N∼45,000. For more complex samples (N≥50,000), the first generation monoliths can intrinsically still provide faster analysis due to their high permeability. It is also demonstrated that - despite the improved efficiency of the second generation monoliths in the practical range of separations (N=10

  17. Oxidative product formation in irradiated neutrophils. A flow cytometric analysis

    SciTech Connect

    Wolber, R.A.; Duque, R.E.; Robinson, J.P.; Oberman, H.A.

    1987-03-01

    The effect of irradiation on neutrophil oxidative function was evaluated using a flow cytometric assay of intracellular hydrogen peroxide (H/sub 2/O/sub 2/) production. This assay quantitates the H/sub 2/O/sub 2/-dependent conversion of the nonfluorescent compound, 2'-7'-dichlorofluorescein (DCFH), into fluorescent 2'-7'-dichlorofluorescein (DCF) on a single-cell basis. Intracellular H/sub 2/O/sub 2/ production in response to stimulation with phorbol myristate acetate was not affected by neutrophil irradiation at doses up to 2500 rad. In addition, irradiation of intracellular DCFH and aqueous 2'-7'-dichlorofluorescein diacetate (DCFH-DA) resulted in DCF production, which suggested that oxidative molecules produced by aqueous radiolysis were detected by this assay. This study indicates that radiation doses of 1500 to 2500 rad, which are sufficient to prevent induction of graft-versus-host disease by transfused blood components, are not deleterious to neutrophil oxidative metabolism.

  18. Investigation of Contact Formation during Silicon Solar Cell Production

    NASA Astrophysics Data System (ADS)

    Mojrová, Barbora

    2016-05-01

    This article deals with the investigation of the influence of sintering conditions on the formation process of screen printed contacts on passivated boron doped P+ emitters. The experiment was focused on measuring of resistance changes of two thick film pastes during firing processes with different conditions. Two different temperature profiles were compared at an atmospheric concentration of O2. The influence of the O2 concentration on resistance was investigated for one profile. A rapid thermal processing furnace modified for in-situ resistance measurements was used. The change of resistance was measured simultaneously with the temperature.

  19. Optimization of monolithic columns for microfluidic devices

    NASA Astrophysics Data System (ADS)

    Pagaduan, Jayson V.; Yang, Weichun; Woolley, Adam T.

    2011-06-01

    Monolithic columns offer advantages as solid-phase extractors because they offer high surface area that can be tailored to a specific function, fast mass transport, and ease of fabrication. Porous glycidyl methacrylate-ethylene glycol dimethacrylate monoliths were polymerized in-situ in microfluidic devices, without pre-treatment of the poly(methyl methacrylate) channel surface. Cyclohexanol, 1-dodecanol and Tween 20 were used to control the pore size of the monoliths. The epoxy groups on the monolith surface can be utilized to immobilize target-specific probes such as antibodies, aptamers, or DNA for biomarker detection. Microfluidic devices integrated with solid-phase extractors should be useful for point-of-care diagnostics in detecting specific biomarkers from complex biological fluids.

  20. Monolithic solid-state lasers for spaceflight

    NASA Astrophysics Data System (ADS)

    Krainak, Michael A.; Yu, Anthony W.; Stephen, Mark A.; Merritt, Scott; Glebov, Leonid; Glebova, Larissa; Ryasnyanskiy, Aleksandr; Smirnov, Vadim; Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth

    2015-02-01

    A new solution for building high power, solid state lasers for space flight is to fabricate the whole laser resonator in a single (monolithic) structure or alternatively to build a contiguous diffusion bonded or welded structure. Monolithic lasers provide numerous advantages for space flight solid-state lasers by minimizing misalignment concerns. The closed cavity is immune to contamination. The number of components is minimized thus increasing reliability. Bragg mirrors serve as the high reflector and output coupler thus minimizing optical coatings and coating damage. The Bragg mirrors also provide spectral and spatial mode selection for high fidelity. The monolithic structure allows short cavities resulting in short pulses. Passive saturable absorber Q-switches provide a soft aperture for spatial mode filtering and improved pointing stability. We will review our recent commercial and in-house developments toward fully monolithic solid-state lasers.

  1. Activated carbon monoliths for methane storage

    NASA Astrophysics Data System (ADS)

    Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; Burress, Jacob; Pfeifer, Peter

    2012-02-01

    The use of adsorbent storage media for natural gas (methane) vehicles allows for the use of non-cylindrical tanks due to the decreased pressure at which the natural gas is stored. The use of carbon powder as a storage material allows for a high mass of methane stored for mass of sample, but at the cost of the tank volume. Densified carbon monoliths, however, allow for the mass of methane for volume of tank to be optimized. In this work, different activated carbon monoliths have been produced using a polymeric binder, with various synthesis parameters. The methane storage was studied using a home-built, dosing-type instrument. A monolith with optimal parameters has been fabricated. The gravimetric excess adsorption for the optimized monolith was found to be 161 g methane for kg carbon.

  2. Hybrid and monolithic integration of planar lightwave circuits (PLCs)

    NASA Astrophysics Data System (ADS)

    Chen, Ray T.

    2008-02-01

    In this paper, we review the status of monolithic and hybrid integration of planar lightwave circuits (PLCs). Building blocks needed for system integration based on polymeric materials, III-V semiconductor materials, LiNbO 3 and SOI on Silicon are summarized with pros and cons. Due to the maturity of silicon CMOS technology, silicon becomes the platform of choice for optical application specific integrated circuits (OASICs). However, the indirect bandgap of silicon makes the formation of electrically pumped silicon laser a remote plausibility which requires hybrid integration of laser sources made out of III-V compound semicouductor.

  3. PREDICTING THE FORMATION OF CHLORINATED AND BROMINATED BY-PRODUCTS.

    EPA Science Inventory

    Although disinfection has been and continues to be one of the major public health advances in the 20th century, the disinfectants themselves may react with naturally-occurring materials in treated water to form unintended by-products which may themselves pose risks. This is of p...

  4. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  5. Automation of the Technological Process to Produce Building Frame-Monolithic Modules Based on Fluoranhydrite

    NASA Astrophysics Data System (ADS)

    Fedorchuk, J.; Sadenova, M.; Rusina, O.

    2016-01-01

    The paper first proposes the automation of the technological process to produce building frame-monolithic modules from production wastes, namely technogenic anhydrite and fluoranhydrite. A functional diagram of the process automation is developed, the devices to perform control and maintenance with account of the production characteristics are chosen.

  6. Enzymic Pathways for Formation of Carotenoid Cleavage Products

    NASA Astrophysics Data System (ADS)

    Fleischmann, Peter; Zorn, Holger

    Degraded carotenoids (apocarotenoids, norisoprenoids) have been a subject of intensive research for several decades. From the perspective of human physiology and nutrition, the retinoids, acting as vitamins, signalling molecules, and visual pigments, attracted the greatest attention (Chapters 15 and 16). Plant scientists, however, detected a wealth of different apocarotenoids, presumably derived by the excentric cleavage of carotenoids in various species, the plant hormone abscisic acid (1, Scheme 6) being the best-investigated example. With the onset of fruit ripening, flower opening or senescence of green tissues, carotenoids are degraded oxidatively to smaller, volatile compounds. The natural biological functions of the reaction products are outlined in Chapter 15. As many of these apocarotenoids act as potent flavour compounds, food chemists and flavourists worldwide have investigated meticulously their structural and sensory properties. Many aspects of carotenoid metabolites and breakdown products as aroma compounds are presented in a comprehensive book [1].

  7. Advances in the development of organic polymer monolithic columns and their applications in food analysis--a review.

    PubMed

    Jandera, Pavel

    2013-10-25

    Monolithic continuous separation media are gradually finding their way to sample pre-treatment, isolation, enrichment and final analytical separations of a plethora of compounds, occurring as food components, additives or contaminants, including pharmaceuticals, pesticides and toxins, which have traditionally been the domain of particulate chromatographic materials. In the present review, recent advances in the technology of monolithic columns and the applications in food analysis are addressed. Silica-based monoliths are excellent substitutes to conventional particle-packed columns, improving the speed of analysis for low-molecular weight compounds, due to their excellent efficiency and high permeability. These properties have been recently appreciated in two-dimensional HPLC, where the performance in the second dimension is of crucial importance. Organic-polymer monoliths in various formats provide excellent separations of biopolymers. Thin monolithic disks or rod columns are widely employed in isolation, purification and pre-treatment of sample containing proteins, peptides or nucleic acid fragments. Monolithic capillaries were originally intended for use in electrochromatography, but are becoming more frequently used for capillary and micro-HPLC. Monoliths are ideal highly porous support media for immobilization or imprinting template molecules, to provide sorbents for shape-selective isolation of target molecules from various matrices occurring in food analysis. The separation efficiency of organic polymer monoliths for small molecules can be significantly improved by optimization of polymerization approach, or by post-polymerization modification. This will enable full utilization of a large variety of available monomers to prepare monoliths with chemistry matching the needs of selectivity of separations of various food samples containing even very polar or ionized compounds.

  8. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

  9. Monolithic integrated-optic TDLAS sensors

    NASA Astrophysics Data System (ADS)

    Frish, Michael B.; Scherer, David R.; Wainner, Richard T.; Allen, Mark G.; Shankar, Raji; Loncar, Marko

    2012-06-01

    We are developing prototype chip-scale low-power integrated-optic gas-phase chemical sensors based on infrared Tunable Diode Laser Absorption Spectroscopy (TDLAS). TDLAS is able to sense many gas phase chemicals with high sensitivity and selectivity. Using semiconductor fabrication and assembly techniques, the low-cost integrated optic TDLAS technology will permit mass production of sensors that have wide ranging industrial, medical, environmental, and consumer applications. Novel gas sensing elements using low-loss resonant photonic crystal cavities or waveguides will permit monolithic integration of a laser source, sampling elements, and detector on a semiconductor materials system substrate. Practical challenges to fabricating these devices include: a) selecting and designing the high-Q micro-resonator sensing element appropriate for the selected analyte; and b) device thermal management, especially stabilizing laser temperature with the precision needed for sensitive spectroscopic detection. In this paper, we analyze the expected sensitivity of micro-resonator-based structures for chemical sensing, and demonstrate a novel approach for exploiting laser waste heat to stabilize the laser temperature.

  10. Pion production via isobar giant resonance formation and decay

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Deutchman, P. A.; Madigan, R. L.; Norbury, J. W.

    1984-01-01

    A spin, isotopic-spin formalism for the production of pions due to decays of isobar giant resonances formed in peripheral heavy-ion collisions is presented. The projectile nucleus isobar giant resonance state is assumed to coherently form and then incoherently decay to produce the pions. Total spin and isotopic spin for the system are conserved through the concomitant excitation of the target nucleus to an isobaric analog giant resonance state. Comparisons of the predicted total pion cross sections, over a range of energies, are made with heavy-ion pion data.

  11. Affinity monolith chromatography: A review of principles and recent analytical applications

    PubMed Central

    Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

    2012-01-01

    Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

  12. Applications of monolithic solid-phase extraction in chromatography-based clinical chemistry assays.

    PubMed

    Bunch, Dustin R; Wang, Sihe

    2013-04-01

    Complex matrices, for example urine, serum, plasma, and whole blood, which are common in clinical chemistry testing, contain many non-analyte compounds that can interfere with either detection or in-source ionization in chromatography-based assays. To overcome this problem, analytes are extracted by protein precipitation, solid-phase extraction (SPE), and liquid-liquid extraction. With correct chemistry and well controlled material SPE may furnish clean specimens with consistent performance. Traditionally, SPE has been performed with particle-based adsorbents, but monolithic SPE is attracting increasing interest of clinical laboratories. Monoliths, solid pieces of stationary phase, have bimodal structures consisting of macropores, which enable passage of solvent, and mesopores, in which analytes are separated. This structure results in low back-pressure with separation capabilities similar to those of particle-based adsorbents. Monoliths also enable increased sample throughput, reduced solvent use, varied support formats, and/or automation. However, many of these monoliths are not commercially available. In this review, application of monoliths to purification of samples from humans before chromatography-based assays will be critically reviewed.

  13. Development of an epoxy-based monolith used for the affinity capturing of Escherichia coli bacteria.

    PubMed

    Peskoller, Caroline; Niessner, Reinhard; Seidel, Michael

    2009-05-01

    An epoxy-based monolith has been developed for use as hydrophilic support in bioseparation. This monolith is produced by self-polymerization of polyglycerol-3-glycidyl ether in organic solvents as porogens at room temperature within 1 h. One receives a highly cross-linked structure that provides useful mechanical properties. The porosity and pore diameter can be controlled by varying the composition of the porogen. In this work, an epoxy-based monolith with a high porosity (79%) and large pore size (22 microm) is prepared and used in affinity capturing of bacterial cells. These features allow the passage of bacterial cells through the column. As affinity ligand polymyxin B is used, which allows the binding of gram-negative bacteria. The efficiency of the monolithic affinity column is studied with Escherichia coli spiked in water. Bacterial cells are concentrated on the column at pH 4 and eluted with a recovery of 97+/-3% in 200 microL by changing the pH value without impairing viability of bacteria. The dynamic capacity for the monolithic column is nearly independent of the flow rate (4x10(9)cells/column). Thereby, it is possible to separate and enrich gram-negative bacterial cells, such as E. coli, with high flow rates (10 mL/min) and low back pressure (<1 bar) in a volume as low as 200 microL compatible for real-time polymerase chain reaction, microarray formats, and biosensors.

  14. Spore formation and toxin production in Clostridium difficile biofilms.

    PubMed

    Semenyuk, Ekaterina G; Laning, Michelle L; Foley, Jennifer; Johnston, Pehga F; Knight, Katherine L; Gerding, Dale N; Driks, Adam

    2014-01-01

    The ability to grow as a biofilm can facilitate survival of bacteria in the environment and promote infection. To better characterize biofilm formation in the pathogen Clostridium difficile, we established a colony biofilm culture method for this organism on a polycarbonate filter, and analyzed the matrix and the cells in biofilms from a variety of clinical isolates over several days of biofilm culture. We found that biofilms readily formed in all strains analyzed, and that spores were abundant within about 6 days. We also found that extracellular DNA (eDNA), polysaccharide and protein was readily detected in the matrix of all strains, including the major toxins A and/or B, in toxigenic strains. All the strains we analyzed formed spores. Apart from strains 630 and VPI10463, which sporulated in the biofilm at relatively low frequencies, the frequencies of biofilm sporulation varied between 46 and 65%, suggesting that variations in sporulation levels among strains is unlikely to be a major factor in variation in the severity of disease. Spores in biofilms also had reduced germination efficiency compared to spores obtained by a conventional sporulation protocol. Transmission electron microscopy revealed that in 3 day-old biofilms, the outermost structure of the spore is a lightly staining coat. However, after 6 days, material that resembles cell debris in the matrix surrounds the spore, and darkly staining granules are closely associated with the spores surface. In 14 day-old biofilms, relatively few spores are surrounded by the apparent cell debris, and the surface-associated granules are present at higher density at the coat surface. Finally, we showed that biofilm cells possess 100-fold greater resistance to the antibiotic metronidazole then do cells cultured in liquid media. Taken together, our data suggest that C. difficile cells and spores in biofilms have specialized properties that may facilitate infection.

  15. Monolithically integrated Ge CMOS laser

    NASA Astrophysics Data System (ADS)

    Camacho-Aguilera, Rodolfo

    2014-02-01

    Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work

  16. A monolith purification process for virus-like particles from yeast homogenate.

    PubMed

    Burden, Claire S; Jin, Jing; Podgornik, Aleš; Bracewell, Daniel G

    2012-01-01

    Monoliths are an alternative stationary phase format to conventional particle based media for large biomolecules. Conventional resins suffer from limited capacities and flow rates when used for viruses, virus-like particles (VLP) and other nanoplex materials. The monolith structure provides a more open pore structure to improve accessibility for these materials and better mass transport from convective flow and reduced pressure drops. To examine the performance of this format for bioprocessing we selected the challenging capture of a VLP from clarified yeast homogenate. Using a recombinant Saccharomyces cerevisiae host it was found hydrophobic interaction based separation using a hydroxyl derivatised monolith had the best performance. The monolith was then compared to a known beaded resin method, where the dynamic binding capacity was shown to be three-fold superior for the monolith with equivalent 90% recovery of the VLP. To understand the impact of the crude feed material confocal microscopy was used to visualise lipid contaminants, deriving from the homogenised yeast. It was seen that the lipid formed a layer on top of the column, even after regeneration of the column with isopropanol, resulting in increasing pressure drops with the number of operational cycles. Removal of the lipid pre-column significantly reduces the amount and rate of this fouling process. Using Amberlite/XAD-4 beads around 70% of the lipid was removed, with a loss of VLP around 20%. Applying a reduced lipid feed versus an untreated feed further increased the dynamic binding capacity of the monolith from 0.11 mg/mL column to 0.25 mg/mL column.

  17. Large format ink-jet poster production: a case report.

    PubMed

    Harris, R

    1998-03-01

    To complement the services offered by the Medical Illustration Department of Frenchay Hospital, Bristol, we decided to look at the possibility of producing posters using the ink-jet process. Our designers wanted to use the full scope of their computers and software to expand their design talents. The method of cutting and pasting sheets of paper onto card seemed old fashioned and denied clients the benefit of the exciting techniques that have become available. After seeking sponsorship, a drug company gave 8000 Pounds towards setting up the department's poster printing service. A Kodak DS1000 printer was installed together with Posterjet and Posterworks software and we went into production, servicing not only our hospital but others in the area who gave their support for the service. High quality photographic reproduction was achieved and clients and consultants were very pleased with the results. The designers were happy that their skills were being used and interest in this and other services in the department have increased. The resulting increased income has helped finance other projects. The printer has enabled us also to see output proofs before sending work off to be offset printed--a very useful tool and a cost-saving process.

  18. A monolithically integrated torsional CMOS-MEMS relay

    NASA Astrophysics Data System (ADS)

    Riverola, M.; Sobreviela, G.; Torres, F.; Uranga, A.; Barniol, N.

    2016-11-01

    We report experimental demonstrations of a torsional microelectromechanical (MEM) relay fabricated using the CMOS-MEMS approach (or intra-CMOS) which exploits the full foundry inherent characteristics enabling drastic reduction of the fabrication costs and batch production. In particular, the relay is monolithically integrated in the back end of line of a commercial standard CMOS technology (AMS 0.35 μm) and released by means of a simple one-step mask-less wet etching. The fabricated torsional relay exhibits an extremely steep switching behaviour symmetrical about both contact sides with an on-state contact resistance in the k Ω -range throughout the on-off cycling test.

  19. Electron transfer pathways of formate-driven H2 production in Desulfovibrio.

    PubMed

    Martins, Mónica; Mourato, Cláudia; Morais-Silva, Fabio O; Rodrigues-Pousada, Claudina; Voordouw, Gerrit; Wall, Judy D; Pereira, Inês A C

    2016-09-01

    The potential of sulfate-reducing bacteria (SRB) as biocatalysts for H2 production from formate was recently demonstrated, but the electron transfer pathways involved were not described. In the present work, we analyzed the H2 production capacity of five Desulfovibrio strains: Desulfovibrio vulgaris, Desulfovibrio desulfuricans, Desulfovibrio alaskensis, Desulfovibrio fructosivorans, and Desulfovibrio gigas. D. vulgaris showed the highest H2 productivity (865 mL Lmedium (-1)), and D. gigas the lowest one (374 mL Lmedium (-1) of H2). The electron transfer pathways involved in formate-driven H2 production by these two organisms were further investigated through the study of deletion mutants of hydrogenases (Hases) and formate dehydrogenases (Fdhs). In D. vulgaris, the periplasmic FdhAB is the key enzyme for formate oxidation and two pathways are apparently involved in the production of H2 from formate: a direct one only involving periplasmic enzymes and a second one that involves transmembrane electron transfer and may allow energy conservation. In the presence of selenium, the Hys [NiFeSe] Hase is the main periplasmic enzyme responsible for H2 production, and the cytoplasmic Coo Hase is apparently involved in the ability of D. vulgaris to grow by converting formate to H2, in sparging conditions. Contrary to D. vulgaris, H2 production in D. gigas occurs exclusively by the direct periplasmic route and does not involve the single cytoplasmic Hase, Ech. This is the first report of the metabolic pathways involved in formate metabolism in the absence of sulfate in SRB, revealing that the electron transfer pathways are species-specific.

  20. Monolithic and mechanical multijunction space solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1990-01-01

    Monolithic and mechanically stacked tandem solar cells have been fabricated with encouraging AM0 efficiencies summarized as: monolithic GaAs/Ge: 19.1 percent (28 C, 4 sq cm); monolithic InP/Ga0.47In0.53As: 22.2 percent (25 C, 0.296 sq cm); monolithic AlGaAs/GaAs/InGaAs: 27.6 percent (80 C, 0.2 sq cm, 100 X); mechanically stacked GaAs/GaSb: 30.8 percent (25 C, 0.049 sq cm, 100 X); and mechanically stacked GaAs/CuInSe2: 23.1 percent (25 C, 4 sq cm). Significant improvement in tandem cell efficiencies nearing to theoretical predictions has been projected with the improvement in cell material quality and processing. Thin-film cells offer improved specific power. It is pointed out that both the monolithic and mechanically stacked cells have their own problems as to size, processing, current-voltage matching, weight, etc. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full spectrum range simulators are required to measure efficiencies correctly.

  1. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    SciTech Connect

    K. C. Kwon

    2006-09-30

    syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives using a monolithic catalyst reactor, experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 40-560 seconds at 120-150 C to evaluate effects of reaction temperatures, total pressure, space time, and catalyst regeneration on conversion of hydrogen sulfide into elemental sulfur and formation of COS. Simulated coal gas mixtures consist of 3,600-4,000-ppmv hydrogen sulfide, 1,800-2,000 ppmv sulfur dioxide, 23-27 v% hydrogen, 36-41 v% CO, 10-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 30-180 SCCM. The temperature of the reactor is controlled in an oven at 120-150 C. The pressure of the reactor is maintained at 40

  2. Fractionation, characterization and C-, N-disinfection byproduct formation of soluble microbial products in MBR processes.

    PubMed

    Ma, Defang; Meng, Yingjie; Xia, Chufan; Gao, Baoyu; Wang, Yan

    2015-12-01

    Soluble microbial products are heterogeneous organic materials generated during microbial growth and decay, which are the major soluble organic matters in MBR effluents and are the primary precursors forming disinfection by-products (DBPs). In this study, biomass associated products (BAP) and utilization associated products (UAP) were separately produced to investigate their physical chemical characteristics and disinfection byproduct (DBP) formation during chlorination in the presence of ammonia. BAP had higher formation reactivity of halogenated carbonaceous and nitrogenous DBPs including trihalomethanes, haloketones, haloacetonitriles and trichloronitromethane due to their higher percentage of large molecular weight (MW) materials and humic substances compared with UAP. However, the nonhalogenated species N-nitrosodimethylamine (NDMA) yield of UAP was twice higher than that of BAP because UAP contained more nitrogenous organic matters with MW<500Da including aromatic polypeptide/amino acid-like materials and secondary amines, which have been proved to have high NDMA formation potential.

  3. Effect of ammonia on ozone-initiated formation of indoor secondary products with emissions from cleaning products

    NASA Astrophysics Data System (ADS)

    Huang, Yu; Lee, Shun Cheng; Ho, Kin Fai; Ho, Steven Sai Hang; Cao, Nanying; Cheng, Yan; Gao, Yuan

    2012-11-01

    Biogenic volatile organic compounds (BVOCs) emitted from cleaning products and air fresheners indoors are prone to oxidation resulting in the formation of secondary pollutants that can pose health risks on residents. Ammonia (NH3) is ubiquitous in ambient and indoor environments. In this study, we investigated the effect of ammonia (NH3) on secondary pollutants formation from the ozonolysis of BVOCs emitted from cleaning products including floor cleaner (FC), kitchen cleaner (KC) and dishwashing detergent (DD) in a large environmental chamber. Our results demonstrated that the presence of NH3 (maximum concentration is 240 ppb) could significantly enhance secondary organic aerosols (SOAs) formation from the ozonolysis of all the three categories of cleaning products. For example, for the FC sample, the maximum total particle concentration was up to 2.0 × 104 # cm-3 in the presence of NH3, while it was 1.3 × 104 # cm-3 which was 35% lower without NH3. However, it was found that the extent of NH3 effect on SOAs formation from the ozonolysis of BVOCs emissions was component-dependent. The presence of NH3 in the reaction systems could increase the consumptions of d-limonene that is the dominant BVOC species as identified in cleaning products. The percent yields (%) of secondary carbonyl compounds generated from the ozonolysis of BVOCs emitted from three categories of cleaning products were identified in the presence and absence of NH3, respectively. The increase in SOAs particle number concentration can be attributed to the formation of condensable salts from reactions between NH3 and organic compounds generated from the BVOCs ozonolysis processes. By investigating the NH3 effect on the ozonolysis of BVOCs mixtures in contrast to the chemistry of individual compounds, a better assessment can be made of the overall impact cleaning products have on real indoor environments.

  4. GaAs monolithic RF modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  5. Taking a Large Monolith to Use for Teaching Soil Morphology.

    ERIC Educational Resources Information Center

    Smith, B. R.; And Others

    1989-01-01

    Described is a technique for taking a large monolith for the purpose of teaching soil structure. Materials and procedures are detailed. A survey of 93 students indicated that the larger monolith was preferred over the commonly used narrow ones. (CW)

  6. Hydrogen production from methane through catalytic partial oxidation reactions

    NASA Astrophysics Data System (ADS)

    Freni, S.; Calogero, G.; Cavallaro, S.

    This paper reviews recent developments in syn-gas production processes used for partial methane oxidation with and/or without steam. In particular, we examined different process charts (fixed bed, fluidised bed, membrane, etc.), kinds of catalysts (powders, foams, monoliths, etc.) and catalytically active phases (Ni, Pt, Rh, etc.). The explanation of the various suggested technical solutions accounted for the reaction mechanism that may selectively lead to calibrated mixtures of CO and H 2 or to the unwanted formation of products of total oxidation (CO 2 and H 2O) and pyrolysis (coke). Moreover, the new classes of catalysts allow the use of small reactors to treat large amounts of methane (monoliths) or separate hydrogen in situ from the other reaction products (membrane). This leads to higher conversions and selectivity than could have been expected thermodynamically. Although catalysts based on Rh are extremely expensive, they can be used to minimise H 2O formation by maximising H 2 yield.

  7. The formation and control of emerging disinfection by-products of health concern.

    PubMed

    Krasner, Stuart W

    2009-10-13

    When drinking water treatment plants disinfect water, a wide range of disinfection by-products (DBPs) of health and regulatory concern are formed. Recent studies have identified emerging DBPs (e.g. iodinated trihalomethanes (THMs) and acids, haloacetonitriles, halonitromethanes (HNMs), haloacetaldehydes, nitrosamines) that may be more toxic than some of the regulated ones (e.g. chlorine- and bromine-containing THMs and haloacetic acids). Some of these emerging DBPs are associated with impaired drinking water supplies (e.g. impacted by treated wastewater, algae, iodide). In some cases, alternative primary or secondary disinfectants to chlorine (e.g. chloramines, chlorine dioxide, ozone, ultraviolet) that minimize the formation of some of the regulated DBPs may increase the formation of some of the emerging by-products. However, optimization of the various treatment processes and disinfection scenarios can allow plants to control to varying degrees the formation of regulated and emerging DBPs. For example, pre-disinfection with chlorine, chlorine dioxide or ozone can destroy precursors for N-nitrosodimethylamine, which is a chloramine by-product, whereas pre-oxidation with chlorine or ozone can oxidize iodide to iodate and minimize iodinated DBP formation during post-chloramination. Although pre-ozonation may increase the formation of trihaloacetaldehydes or selected HNMs during post-chlorination or chloramination, biofiltration may reduce the formation potential of these by-products.

  8. Hydrogen production in anaerobic reactors during shock loads--influence of formate production and H2 kinetics.

    PubMed

    Voolapalli, R K; Stuckey, D C

    2001-05-01

    In this article the role of hydrogen as a process monitoring tool in methanogenic systems was studied by considering the influence of several key system parameters. Hydrogen production was found to be influenced mainly by the inocula's source pH, and varied only slightly with external pH and HCO3- levels. When an inoculum adapted to above neutral conditions (pH > 7) was shocked, reducing equivalents were selectively channelled through formate, while high hydrogen production was noticed with acidically (pH < 6.5) adapted inocula. The results also revealed that the production of hydrogen or formate during shock loads was not strongly associated with microbial morphology (granules or flocs) as high electron fluxes were possible through either during acidogenesis. Shock load experiments in continuous reactors revealed that neither hydrogen nor formate accumulated to any significant degree, nevertheless digester recovery took a long time due to the slow kinetics of volatile fatty acid degradation. Selective formate production under neutral pH environments, coupled with high hydrogenotrophic activity, was found to be responsible for the dampened hydrogen response during the early phases of gradually shocked systems (step change). Based on these results it appears that the role of hydrogen as a process monitoring tool has been overemphasised in the literature.

  9. Monolithically integrated HgCdTe focal plane arrays

    NASA Astrophysics Data System (ADS)

    Velicu, Silviu; Lee, Tae-Seok; Ashokan, Renganathan; Grein, Christoph H.; Boieriu, Paul; Chen, Y. P.; Dinan, John H.; Lianos, Dimitrios

    2003-12-01

    The cost and performance of hybrid HgCdTe infrared focal plane arrays are constrained by the necessity of fabricating the detector arrays on a CdZnTe substrate. These substrates are expensive, fragile, are available only in small rectangular formats, and are not a good thermal expansion match to the silicon readout integrated circuit. We discuss in this paper an infrared sensor technology based on monolithically integrated infrared focal plane arrays that could replace the conventional hybrid focal plane array technology. We have investigated the critical issues related to the growth of HgCdTe on Si read-out integrated circuits and the fabrication of monolithic focal plane arrays: (1) the design of Si read-out integrated circuits and focal plane array layouts, (2) the low temperature cleaning of Si(001) wafers, (3) growth of CdTe and HgCdTe layers on read-out integrated circuits, (4) array fabrication, interconnection between focal plane array and read-out integrated circuit input nodes and demonstration of the photovoltaic operation, and (5) maintenance of the read-out integrated circuit characteristics after substrate cleaning, molecular beam epitaxy growth and device fabrication. Crystallographic, optical and electrical properties of the grown layers are presented. Electrical properties for diodes fabricated on misoriented Si and read-out integrated circuit substrates are discussed. The fabrication of arrays with demonstrated I-V properties show that monolithic integration of HgCdTe-based infrared focal plane arrays on Si read-out integrated circuits is feasible and could be implemented in the 3rd generation of infrared systems.

  10. Combining monolithic zirconia crowns, digital impressioning, and regenerative cement for a predictable restorative alternative to PFM.

    PubMed

    Griffin, Jack D

    2013-03-01

    Advances in indirect esthetic materials in recent years have provided the dental profession higher levels of strength and esthetics than ever before with products like lithium disilicate and zirconium oxide. Providing excellent fit and versatile performance, and because there is no porcelain to delaminate, chip, or fracture, monolithic zirconia crowns have the potential to outperform other layered restorations such as porcelain-fused-to-metal (PFM). This review of monolithic zirconia highlights a clinical case in which all-zirconia restorations were combined with CAD/CAM technology for a successful esthetic restorative outcome.

  11. Consolidation and densification methods for fibrous monolith processing

    SciTech Connect

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2006-06-20

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  12. Designing Catalytic Monoliths For Closed-Cycle CO2 Lasers

    NASA Technical Reports Server (NTRS)

    Guinn, Keith; Herz, Richard K.; Goldblum, Seth; Noskowski, ED

    1992-01-01

    LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) computer program aids in design of catalyst in monolith by simulating effects of design decisions on performance of laser. Provides opportunity for designer to explore tradeoffs among activity and dimensions of catalyst, dimensions of monolith, pressure drop caused by flow of gas through monolith, conversion of oxygen, and other variables. Written in FORTRAN 77.

  13. The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

    PubMed Central

    Palmfeldt, Johan; Paese, Marco; Hahn-Hägerdal, Bärbel; van Niel, Ed W. J.

    2004-01-01

    Lactococcus lactis grows homofermentatively on glucose, while its growth on maltose under anaerobic conditions results in mixed acid product formation in which formate, acetate, and ethanol are formed in addition to lactate. Maltose was used as a carbon source to study mixed acid product formation as a function of the growth rate. In batch and nitrogen-limited chemostat cultures mixed acid product formation was shown to be linked to the growth rate, and homolactic fermentation occurred only in resting cells. Two of the four lactococcal strains investigated with maltose, L. lactis 65.1 and MG1363, showed more pronounced mixed acid product formation during growth than L. lactis ATCC 19435 or IL-1403. In resting cell experiments all four strains exhibited homolactic fermentation. In resting cells the intracellular concentrations of ADP, ATP, and fructose 1,6-bisphosphate were increased and the concentration of Pi was decreased compared with the concentrations in growing cells. Addition of an ionophore (monensin or valinomycin) to resting cultures of L. lactis 65.1 induced mixed acid product formation concomitant with decreases in the ADP, ATP, and fructose 1,6-bisphosphate concentrations. ADP and ATP were shown to inhibit glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alcohol dehydrogenase in vitro. Alcohol dehydrogenase was the most sensitive enzyme and was totally inhibited at an adenine nucleotide concentration of 16 mM, which is close to the sum of the intracellular concentrations of ADP and ATP of resting cells. This inhibition of alcohol dehydrogenase might be partially responsible for the homolactic behavior of resting cells. A hypothesis regarding the level of the ATP-ADP pool as a regulating mechanism for the glycolytic flux and product formation in L. lactis is discussed. PMID:15345435

  14. Elimination of formate production in Clostridium thermocellum

    SciTech Connect

    Rydzak, Thomas; Lynd, Lee R.; Guss, Adam M.

    2015-07-11

    We study the ability of Clostridium thermocellum to rapidly degrade cellulose and ferment resulting hydrolysis products into ethanol makes it a promising platform organism for cellulosic biofuel production via consolidated bioprocessing. Currently, however, ethanol yield are far below theoretical maximum due to branched product pathways that divert carbon and electrons towards formate, H2, lactate, acetate, and secreted amino acids. To redirect carbon and electron flux away from formate, pyruvate:formate lyase (pfl) and respective PFL-activating enzyme were deleted. Formate production in the resulting Δpfl strain was eliminated and acetate production decreased by 50% on both complex and defined medium. Growth rate of Δpfl decreased by 2.9-fold on defined medium and diauxic growth was observed on complex medium. Supplementation of defined medium with 2 mM formate restored Δpfl growth rate to 80% of the parent strain. Finally, we discuss the role of pfl in metabolic engineering strategies and C1 metabolism.

  15. Monolithic and mechanical multijunction space solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1992-01-01

    High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since the two approaches are still in the developmental stage.

  16. Development of a monolithic ferrite memory array

    NASA Technical Reports Server (NTRS)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  17. A 30 GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Mondal, J.; Contolatis, T.; Geddes, J.; Bauhahn, P.; Sokolov, V.

    1990-01-01

    The technical achievements and deliveries made during the duration of the program to develop a 30 GHz monolithic receive module for communication feed array applications and to deliver submodules and 30 GHz monolithic receive modules for experimental evaluation are discussed. Key requirements include an overall receive module noise figure of 5 dB, a 30 dB RF-to-RF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. In addition, the monolithic receive module design addresses a cost goal of less than one thousand dollars (1980 dollars) per module in unit buys of 5,000 or more, and a mechanical configuration that is applicable to a spaceborne phase array system. An additional task for the development and delivery of 32 GHz phase shifter integrated circuit (IC) for deep space communication is also described.

  18. Polymer network/carbon layer on monolith support and monolith catalytic reactor

    DOEpatents

    Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

    2003-08-26

    The present invention relates to an improved monolith catalytic reactor and a monolith support. The improvement in the support resides in a polymer network/carbon coating applied to the surface of a porous substrate and a catalytic metal, preferably a transition metal catalyst applied to the surface of the polymer network/carbon coating. The monolith support has from 100 to 800 cells per square inch and a polymer network/carbon coating with surface area of from 0.1 to 15 m.sup.2 /gram as measured by adsorption of N.sub.2 or Kr using the BET method.

  19. Monolithic amorphous silicon modules on continuous polymer substrate

    SciTech Connect

    Grimmer, D.P. )

    1992-03-01

    This report examines manufacturing monolithic amorphous silicon modules on a continuous polymer substrate. Module production costs can be reduced by increasing module performance, expanding production, and improving and modifying production processes. Material costs can be reduced by developing processes that use a 1-mil polyimide substrate and multilayers of low-cost material for the front encapsulant. Research to speed up a-Si and ZnO deposition rates is needed to improve throughputs. To keep throughput rates compatible with depositions, multibeam fiber optic delivery systems for laser scribing can be used. However, mechanical scribing systems promise even higher throughputs. Tandem cells and production experience can increase device efficiency and stability. Two alternative manufacturing processes are described: (1) wet etching and sheet handling and (2) wet etching and roll-to-roll fabrication.

  20. The 30-GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Bauhahn, P.; Geddes, J.; Sokolov, V.; Contolatis, T.

    1988-01-01

    The fourth year progress is described on a program to develop a 27.5 to 30 GHz GaAs monolithic receive module for spaceborne-communication antenna feed array applications, and to deliver submodules for experimental evaluation. Program goals include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. Submicron gate length single and dual gate FETs are described and applied in the development of monolithic gain control amplifiers and low noise amplifiers. A two-stage monolithic gain control amplifier based on ion implanted dual gate MESFETs was designed and fabricated. The gain control amplifier has a gain of 12 dB at 29 GHz with a gain control range of over 13 dB. A two-stage monolithic low noise amplifier based on ion implanted MESFETs which provides 7 dB gain with 6.2 dB noise figure at 29 GHz was also developed. An interconnected receive module containing LNA, gain control, and phase shifter submodules was built using the LNA and gain control ICs as well as a monolithic phase shifter developed previously under this program. The design, fabrication, and evaluation of this interconnected receiver is presented. Progress in the development of an RF/IF submodule containing a unique ion implanted diode mixer diode and a broadband balanced mixer monolithic IC with on-chip IF amplifier and the initial design of circuits for the RF portion of a two submodule receiver are also discussed.

  1. Physical and chemical sensing using monolithic semiconductor optical transducers

    NASA Astrophysics Data System (ADS)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  2. Distributed Amplifier Monolithic Microwave Integrated Circuit (MMIC) Design

    DTIC Science & Technology

    2012-10-01

    Distributed Amplifier Monolithic Microwave Integrated Circuit (MMIC) Design by John E. Penn ARL-TR-6237 October 2012...Distributed Amplifier Monolithic Microwave Integrated Circuit (MMIC) Design John E. Penn Sensors and Electron Devices Directorate, ARL...TITLE AND SUBTITLE Distributed Amplifier Monolithic Microwave Integrated Circuit (MMIC) Design 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  3. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte-liposome interactions by capillary liquid chromatography.

    PubMed

    Moravcová, Dana; Planeta, Josef; Wiedmer, Susanne K

    2013-11-22

    This study introduces a silica-based monolith in a capillary format (0.1 mm × 100 mm) as a support for immobilization of liposomes and its characterization in immobilized liposome chromatography. Silica-based monolithic capillary columns prepared by acidic hydrolysis of tetramethoxysilane in the presence of polyethylene glycol and urea were modified by (3-aminopropyl)trimethoxysilane, whereby amino groups were introduced to the monolithic surface. These groups undergo reaction with glutaraldehyde to form an iminoaldehyde, allowing covalent binding of pre-formed liposomes containing primary amino groups. Two types of phospholipid vesicles were used for column modification; these were 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidyl choline with and without 1,2-diacyl-sn-glycero-3-phospho-L-serine. The prepared columns were evaluated under isocratic separation conditions employing 20mM phosphate buffer at pH 7.4 as a mobile phase and a set of unrelated drugs as model analytes. The liposome layer on the synthesized columns significantly changed the column selectivity compared to the aminopropylsilylated monolithic stationary phase. Monolithic columns modified by liposomes were stable under the separation conditions, which proved the applicability of the suggested preparation procedure for the synthesis of capillary columns dedicated to study analyte-liposome interactions. The column efficiency originating from the silica monolith was preserved and reached, e.g., more than 120,000 theoretical plates/m for caffeine as a solute.

  4. Chiral monolithic absorbent constructed by optically active helical-substituted polyacetylene and graphene oxide: preparation and chiral absorption capacity.

    PubMed

    Li, Weifei; Wang, Bo; Yang, Wantai; Deng, Jianping

    2015-02-01

    Chiral monolithic absorbent is successfully constructed for the first time by using optically active helical-substituted polyacetylene and graphene oxide (GO). The preparative strategy is facile and straightforward, in which chiral-substituted acetylene monomer (Ma), cross-linker (Mb), and alkynylated GO (Mc) undergo copolymerization to form the desired monolithic absorbent in quantitative yield. The resulting monoliths are characterized by circular dichroism, UV-vis absorption, scanning electron microscopy (SEM), FT-IR, Raman, energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), XPS, and thermogravimetric analysis (TGA) techniques. The polymer chains derived from Ma form chiral helical structures and thus provide optical activity to the monoliths, while GO sheets contribute to the formation of porous structures. The porous structure enables the monolithic absorbents to demonstrate a large swelling ratio in organic solvents, and more remarkably, the helical polymer chains provide optical activity and further enantio-differentiating absorption ability. The present study establishes an efficient and versatile methodology for preparing novel functional materials, in particular monolithic chiral materials based on substituted polyacetylene and GO.

  5. The Mechanisms of Inhibition of Advanced Glycation End Products Formation through Polyphenols in Hyperglycemic Condition.

    PubMed

    Khangholi, Shahpour; Majid, Fadzilah Adibah Abdul; Berwary, Najat Jabbar Ahmed; Ahmad, Farediah; Aziz, Ramlan Bin Abd

    2016-01-01

    Glycation, the non-enzymatic binding of glucose to free amino groups of an amino acid, yields irreversible heterogeneous compounds known as advanced glycation end products. Those products play a significant role in diabetic complications. In the present article we briefly discuss the contribution of advanced glycation end products to the pathogenesis of diabetic complications, such as atherosclerosis, diabetic retinopathy, nephropathy, neuropathy, and wound healing. Then we mention the various mechanisms by which polyphenols inhibit the formation of advanced glycation end products. Finally, recent supporting documents are presented to clarify the inhibitory effects of polyphenols on the formation of advanced glycation end products. Phytochemicals apply several antiglycation mechanisms, including glucose metabolism, amelioration of oxidative stress, scavenging of dicarbonyl species, and up/down-regulation of gene expression. To utilize polyphenols in order to remedy diabetic complications, we must explore, examine and clarify the action mechanisms of the components of polyphenols.

  6. UPDATE ON MONOLITHIC FUEL FABRICATION METHODS

    SciTech Connect

    C. R. Clark; J. F. Jue; G. A. Moore; N. P. Hallinan; B. H. Park; D. E. Burkes

    2006-10-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Progress at INL has led to fabrication of hot isostatic pressed uranium-molybdenum bearing monolithic fuel plates. These miniplates are part of the RERTR-8 miniplate irradiation test. Further progress has also been made on friction stir weld processing which has been used to fabricate full size fuel plates which will be irradiated in the ATR and OSIRIS reactors.

  7. Increased thermal conductivity monolithic zeolite structures

    DOEpatents

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  8. Cytotoxical products formation on the nanoparticles heated by the pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Kogan, Boris Ya.; Titov, Andrey A.; Rakitin, Victor Yu.; Kvacheva, Larisa D.; Kuzmin, Sergey G.; Vorozhtsov, Georgy N.

    2006-02-01

    Cytotoxical effect of a pulsed laser irradiation in presence of nanoparticles of carbon black, sulphuretted carbon and fullerene-60 on death of human uterus nick cancer HeLa and mice lymphoma P 388 cells was studied in vitro. Bubbles formation as result of "microexplosions" of nanoparticles is one of possible mechanisms of this effect. Other possible mechanism is cytotoxical products formation in result of pyrolysis of nanoparticles and biomaterial which is adjoining. The cytotoxical effect of addition of a supernatant from the carbon nanoparticles suspensions irradiated by the pulsed laser was studied to test this assumption. Analysis using gas chromatograph determined that carbon monoxide is principal gaseous product of such laser pyrolysis. This is known as cytotoxical product. Efficiency of its formation is estimated.

  9. Chlorination and chloramination of tetracycline antibiotics: disinfection by-products formation and influential factors.

    PubMed

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Zhu, Shumin; Ma, Yan; Deng, Jing

    2014-09-01

    Formation of disinfection by-products (DBPs) from chlorination and chloramination of tetracycline antibiotics (TCs) was comprehensively investigated. It was demonstrated that a connection existed between the transformation of TCs and the formation of chloroform (CHCl3), carbon tetrachloride (CCl4), dichloroacetonitrile (DCAN) and dichloroacetone (DCAce). Factors evaluated included chlorine (Cl2) and chloramine(NH2Cl) dosage, reaction time, solution pH and disinfection modes. Increased Cl2/NH2Cl dosage and reaction time improved the formation of CHCl3 and DCAce. Formation of DCAN followed an increasing and then decreasing pattern with increasing Cl2 dosage and prolonged reaction time. pH affected DBPs formation differently, with CHCl3 and DCAN decreasing in chlorination, and having maximum concentrations at pH 7 in chloramination. The total concentrations of DBPs obeyed the following order: chlorination>chloramination>pre-chlorination (0.5h)>pre-chlorination (1h)>pre-chlorination (2h).

  10. Effects of nutrition label format and product assortment on the healthfulness of food choice.

    PubMed

    Aschemann-Witzel, Jessica; Grunert, Klaus G; van Trijp, Hans C M; Bialkova, Svetlana; Raats, Monique M; Hodgkins, Charo; Wasowicz-Kirylo, Grazyna; Koenigstorfer, Joerg

    2013-12-01

    This study aims to find out whether front-of-pack nutrition label formats influence the healthfulness of consumers' food choices and important predictors of healthful choices, depending on the size of the choice set that is made available to consumers. The predictors explored were health motivation and perceived capability of making healthful choices. One thousand German and Polish consumers participated in the study that manipulated the format of nutrition labels. All labels referred to the content of calories and four negative nutrients and were presented on savoury and sweet snacks. The different formats included the percentage of guideline daily amount, colour coding schemes, and text describing low, medium and high content of each nutrient. Participants first chose from a set of 10 products and then from a set of 20 products, which was, on average, more healthful than the first choice set. The results showed that food choices were more healthful in the extended 20-product (vs. 10-product) choice set and that this effect is stronger than a random choice would produce. The formats colour coding and texts, particularly colour coding in Germany, increased the healthfulness of product choices when consumers were asked to choose a healthful product, but not when they were asked to choose according to their preferences. The formats did not influence consumers' motivation to choose healthful foods. Colour coding, however, increased consumers' perceived capability of making healthful choices. While the results revealed no consistent differences in the effects between the formats, they indicate that manipulating choice sets by including healthier options is an effective strategy to increase the healthfulness of food choices.

  11. Sensitivty of ozone production to organic nitrate formation in Sacramento and Los Angeles

    NASA Astrophysics Data System (ADS)

    Browne, E. C.; Cohen, R. C.

    2010-12-01

    Total alkyl and multifunctional nitrates (ΣANs) are formed by a minor channel of the NO + RO2 reaction and thus represent a termination step of ozone production. ΣANs formation becomes most significant in the cross-over regime between NOx saturated (VOC limited) and NOx limited ozone production. In models that fail to account for changing rates of ΣANs formation, the NOx and VOC levels are considered independent parameters: to lower ozone production all that is needed is to decrease the limiting parameter. It has been recently shown that this view on ozone production may lead to counterproductive air quality control strategies (Farmer et al., 2010 submitted). Using both an analytical model and measurements from Mexico City, Farmer et al. demonstrated that ΣANs formation effectively couples VOCs and NOx. Analytical models show that VOC reduction strategies that result in a decrease in ΣANs yield will result in increased ozone production for NOx less than 3 ppb. We expand upon the work of Farmer et al. by investigating the sensitivity of ozone production to ΣANs formation using a regional three dimensional chemical transport model, WRF-CHEM. The standard chemistry treats all ΣANs species as a single model species with a given lifetime and NOx recycling efficiency. We implement a revised ΣANs representation that treats monofunctional, multifunctional saturated, multifunctional unsaturated, aromatic, isoprene, and monoterpene nitrates as unique model species with appropriate lifetimes and NOx recycling efficiencies. We investigate how this improved ΣANs representation affects ozone, and we compare these results to ground and airborne measurements in the Sacramento and Los Angeles areas. Additionally, we investigate the sensitivity of ozone formation to ΣANs formation rate, lifetime, and NOx recycling efficiency.

  12. Endogenous hydrogen peroxide increases biofilm formation by inducing exopolysaccharide production in Acinetobacter oleivorans DR1

    PubMed Central

    Jang, In-Ae; Kim, Jisun; Park, Woojun

    2016-01-01

    In this study, we investigated differentially expressed proteins in Acinetobacter oleivorans cells during planktonic and biofilm growth by using 2-dimensional gel electrophoresis combined with matrix-assisted laser desorption time-of-flight mass spectrometry. We focused on the role of oxidative stress resistance during biofilm formation using mutants defective in alkyl hydroperoxide reductase (AhpC) because its production in aged biofilms was enhanced compared to that in planktonic cells. Results obtained using an ahpC promoter-gfp reporter vector showed that aged biofilms expressed higher ahpC levels than planktonic cells at 48 h. However, at 24 h, ahpC expression was higher in planktonic cells than in biofilms. Deletion of ahpC led to a severe growth defect in rich media that was not observed in minimal media and promoted early biofilm formation through increased production of exopolysaccharide (EPS) and EPS gene expression. Increased endogenous H2O2 production in the ahpC mutant in rich media enhanced biofilm formation, and this enhancement was not observed in the presence of antioxidants. Exogenous addition of H2O2 promoted biofilm formation in wild type cells, which suggested that biofilm development is linked to defense against H2O2. Collectively, our data showed that EPS production caused by H2O2 stress enhances biofilm formation in A. oleivorans. PMID:26884212

  13. Factors affecting catalysis of copper corrosion products in NDMA formation from DMA in simulated premise plumbing.

    PubMed

    Zhang, Hong; Andrews, Susan A

    2013-11-01

    This study investigated the effects of corrosion products of copper, a metal commonly employed in household plumbing systems, on N-nitrosodimethylamine (NDMA) formation from a known NDMA precursor, dimethylamine (DMA). Copper-catalyzed NDMA formation increased with increasing copper concentrations, DMA concentrations, alkalinity and hardness, but decreased with increasing natural organic matter (NOM) concentration. pH influenced the speciation of chloramine and the interactions of copper with DMA. The transformation of monochloramine (NH2Cl) to dichloramine and complexation of copper with DMA were involved in elevating the formation of NDMA by copper at pH 7.0. The inhibiting effect of NOM on copper catalysis was attributed to the rapid consumption of NH2Cl by NOM and/or the competitive complexation of NOM with copper to limit the formation of DMA-copper complexes. Hardness ions, as represented by Ca(2+), also competed with copper for binding sites on NOM, thereby weakening the inhibitory effect of NOM on NDMA formation. Common copper corrosion products also participated in these reactions but in different ways. Aqueous copper released from malachite [Cu2CO3(OH)2] was shown to promote NDMA formation while NDMA formation decreased in the presence of CuO, most likely due to the adsorption of DMA.

  14. Grafted Polymethylhydrosiloxane on Hierarchically Porous Silica Monoliths: A New Path to Monolith-Supported Palladium Nanoparticles for Continuous Flow Catalysis Applications.

    PubMed

    Pélisson, Carl-Hugo; Nakanishi, Takahiro; Zhu, Yang; Morisato, Kei; Kamei, Toshiyuki; Maeno, Ayaka; Kaji, Hironori; Muroyama, Shunki; Tafu, Masamoto; Kanamori, Kazuyoshi; Shimada, Toyoshi; Nakanishi, Kazuki

    2017-01-11

    Polymethylhydrosiloxane has been grafted on the surface of a hierarchically porous silica monolith using a facile catalytic reaction between Si-H and silanol to anchor the polymer. This easy methodology leads to the functionalization of the surface of a silica monolith, where a large amount of free Si-H bonds remain available for reducing metal ions in solution. Palladium nanoparticles of 15 nm have been synthesized homogeneously inside the mesopores of the monolith without any stabilizers, using a flow of a solution containing Pd(2+). This monolith was used as column-type fixed bed catalyst for continuous flow hydrogenation of styrene and selective hydrogenation of 3-hexyn-1-ol, in each case without a significant decrease of the catalytic activity after several hours or days. Conversion, selectivity, and stereoselectivity of the alkyne hydrogenation can be tuned by flow rates of hydrogen and the substrate solution, leading to high productivity (1.57 mol g(Pd)(-1) h(-1)) of the corresponding cis-alkene.

  15. Formation and degradation of valuable intermediate products during wet oxidation of municipal sludge.

    PubMed

    Baroutian, Saeid; Gapes, Daniel J; Sarmah, Ajit K; Farid, Mohammed M; Young, Brent R

    2016-04-01

    The current study investigated the formation of organic acids and alcohols as major intermediate products of wet oxidation of municipal sludge. Municipal sludge was subjected to 60-min wet oxidation at temperatures ranging from 220 to 240°C, with 20bar oxygen partial pressure. Acetic acid was the main intermediate compound produced in this study, followed by propionic, n-butyric, iso-butyric and pentanoic acids and methanol. It was found that the process severity has a significant influence on the formation and degradation of these intermediate products.

  16. Desulfovibrio vulgaris Growth Coupled to Formate-Driven H2 Production.

    PubMed

    Martins, Mónica; Mourato, Cláudia; Pereira, Inês A C

    2015-12-15

    Formate is recognized as a superior substrate for biological H2 production by several bacteria. However, the growth of a single organism coupled to this energetic pathway has not been shown in mesophilic conditions. In the present study, a bioreactor with gas sparging was used, where we observed for the first time that H2 production from formate can be coupled with growth of the model sulfate-reducing bacterium Desulfovibrio vulgaris in the absence of sulfate or a syntrophic partner. In these conditions, D. vulgaris had a maximum growth rate of 0.078 h(-1) and a doubling time of 9 h, and the ΔG of the reaction ranged between -21 and -18 kJ mol(-1). This is the first report of a single mesophilic organism that can grow while catalyzing the oxidation of formate to H2 and bicarbonate. Furthermore, high volumetric and specific H2 production rates (125 mL L(-1) h(-1) and 2500 mL gdcw(-1) h(-1)) were achieved in a new bioreactor designed and optimized for H2 production. This high H2 production demonstrates that the nonconventional H2-producing organism D. vulgaris is a good biocatalyst for converting formate to H2.

  17. Acetoacetate promotes the formation of fluorescent advanced glycation end products (AGEs).

    PubMed

    Bohlooli, Mousa; Ghaffari-Moghaddam, Mansour; Khajeh, Mostafa; Aghashiri, Zohre; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2016-12-01

    Acetoacetate (AA) is an important ketone body, which produces reactive oxygen species (ROS). Advanced glycation end products (AGEs) are defined as final products of glycation process whose production is influenced by the levels of ROS. The accumulation of AGEs in the body contributes to pathogenesis of many diseases including complications of diabetes, and Alzheimer's and Parkinson's disease. Here, we evaluated the impact of AA on production of AGEs upon incubation of human serum albumin (HSA) with glucose. The effect of AA on the AGEs formation of HSA was studied under physiological conditions after incubation with glucose for 35 days. The physical techniques including circular dichroism (CD) and fluorescence spectroscopy were used to assess the impact of AA on formation and structural changes of glycated HSA (GHSA). Our results indicated that the secondary and tertiary structural changes of GHSA were increased in the presence of AA. The fluorescence intensity measurements of AGEs also showed an increase in AGEs formation. Acetoacetate has an activator effect in formation of AGEs through ROS production. The presence of AA may result in enhanced glycation in the presence of glucose and severity of complications associated with accumulation of AGEs.

  18. Biofilm formation, phenotypic production of cellulose and gene expression in Salmonella enterica decrease under anaerobic conditions.

    PubMed

    Lamas, A; Miranda, J M; Vázquez, B; Cepeda, A; Franco, C M

    2016-12-05

    Salmonella enterica subsp. enterica is one of the main food-borne pathogens. This microorganism combines an aerobic life outside the host with an anaerobic life within the host. One of the main concerns related to S. enterica is biofilm formation and cellulose production. In this study, biofilm formation, morphotype, cellulose production and transcription of biofilm and quorum sensing-related genes of 11 S. enterica strains were tested under three different conditions: aerobiosis, microaerobiosis, and anaerobiosis. The results showed an influence of oxygen levels on biofilm production. Biofilm formation was significantly higher (P<0.05) in aerobiosis than in microaerobiosis and anaerobiosis. Cellulose production and RDAR (red, dry, and rough) were expressed only in aerobiosis. In microaerobiosis, the strains expressed the SAW (smooth and white) morphotype, while in anaerobiosis the colonies appeared small and red. The expression of genes involved in cellulose synthesis (csgD and adrA) and quorum sensing (sdiA and luxS) was reduced in microaerobiosis and anaerobiosis in all S. enterica strains tested. This gene expression levels were less reduced in S. Typhimurium and S. Enteritidis compared to the tested serotypes. There was a relationship between the expression of biofilm and quorum sensing-related genes. Thus, the results from this study indicate that biofilm formation and cellulose production are highly influenced by atmospheric conditions. This must be taken into account as contamination with these bacteria can occur during food processing under vacuum or modified atmospheres.

  19. Glucose Metabolism in Sediments of a Eutrophic Lake: Tracer Analysis of Uptake and Product Formation

    PubMed Central

    King, Gary M.; Klug, M. J.

    1982-01-01

    The uptake of glucose and the formation of end products from glucose catabolism have been measured for sediments of eutrophic Wintergreen Lake with a combination of tritiated and 14C-labeled tracers. Time course analyses of the loss of [3H]glucose from sediments were used to establish rate constants for glucose uptake at natural substrate concentrations. Turnover times from these analyses were about 1 min for littoral and profundal sediments. No seasonal or site differences were noted in turnover times. Time course analyses of [U-14C]glucose uptake and 14C-labeled end product formation indicated that glucose mass flow could not be calculated from end product formation since the specific activity of added [14C]glucose was significantly diluted by pools of intracellular glucose and glucose metabolites. Mass flow could only be accurately estimated by use of rates of uptake from tracer studies. Intermediate fermentation end products included acetate (71%), propionate (15%), lactate (9%), and only minor amounts of butyrates or valerates. Addition of H2 to sediments resulted in greater production of lactate (28%) and decreased formation of acetate (50%), but did not affect glucose turnover. Depth profiles of glucose uptake indicated that rates of uptake decreased with depth over the 0- to 18-cm interval and that glucose uptake accounted for 30 to 40% of methanogenesis in profundal sediments. PMID:16346148

  20. Process development for hydrogen production with Chlamydomonas reinhardtii based on growth and product formation kinetics.

    PubMed

    Lehr, Florian; Morweiser, Michael; Rosello Sastre, Rosa; Kruse, Olaf; Posten, Clemens

    2012-11-30

    Certain strains of microalgae are long known to produce hydrogen under anaerobic conditions. In Chlamydomonas reinhardtii the oxygen-sensitive hydrogenase enzyme recombines electrons from the chloroplast electron transport chain with protons to form molecular hydrogen directly inside the chloroplast. A sustained hydrogen production can be obtained under low sulfur conditions in C. reinhardtii, reducing the net oxygen evolution by reducing the photosystem II activity and thereby overcoming the inhibition of the hydrogenases. The development of specially adapted hydrogen production strains led to higher yields and optimized biological process preconditions. So far sustainable hydrogen production required a complete exchange of the growth medium to establish sulfur-deprived conditions after biomass growth. In this work we demonstrate the transition from the biomass growth phase to the hydrogen production phase in a single batch culture only by exact dosage of sulfur. This eliminates the elaborate and energy intensive solid-liquid separation step and establishes a process strategy to proceed further versus large scale production. This strategy has been applied to determine light dependent biomass growth and hydrogen production kinetics to assess the potential of H₂ production with C. reinhardtii as a basis for scale up and further process optimization.

  1. Emission characteristics of VOCs emitted from consumer and commercial products and their ozone formation potential.

    PubMed

    Dinh, Trieu-Vuong; Kim, Su-Yeon; Son, Youn-Suk; Choi, In-Young; Park, Seong-Ryong; Sunwoo, Young; Kim, Jo-Chun

    2015-06-01

    The characteristics of volatile organic compounds (VOCs) emitted from several consumer and commercial products (body wash, dishwashing detergent, air freshener, windshield washer fluid, lubricant, hair spray, and insecticide) were studied and compared. The spray products were found to emit the highest amount of VOCs (~96 wt%). In contrast, the body wash products showed the lowest VOC contents (~1.6 wt%). In the spray products, 21.6-96.4 % of the VOCs were propane, iso-butane, and n-butane, which are the components of liquefied petroleum gas. Monoterpene (C10H16) was the dominant component of the VOCs in the non-spray products (e.g., body wash, 53-88 %). In particular, methanol was present with the highest amount of VOCs in windshield washer fluid products. In terms of the number of carbon, the windshield washer fluids, lubricants, insecticides, and hair sprays comprised >95 % of the VOCs in the range C2-C5. The VOCs in the range C6-C10 were predominantly found in the body wash products. The dishwashing detergents and air fresheners contained diverse VOCs from C2 to C11. Besides comprising hazardous VOCs, VOCs from consumer products were also ozone precursors. The ozone formation potential of the consumer and commercial spray products was estimated to be higher than those of liquid and gel materials. In particular, the hair sprays showed the highest ozone formation potential.

  2. Secondary Organic Aerosol Formation by Molecular-Weight Building Reactions of Biogenic Oxidation Products

    NASA Astrophysics Data System (ADS)

    Barsanti, K.; Guenther, A.; Matsunaga, S.; Smith, J.

    2006-12-01

    Understanding the chemical composition of atmospheric organic aerosols (OA) remains one of the significant challenges to accurately representing OA in air quality and climate models. Meeting this challenge will require further understanding of secondary organic aerosols (SOA), of which biogenic emissions are thought to be major precursors. Of recent interest is the significance of higher-molecular weight (MW) compounds (i.e., "oligomers"). Theoretical, laboratory, and field study results suggest that relatively volatile oxidation products may contribute to SOA formation through multi-phase MW- building reactions. The significance of such reactions for biogenic SOA formation, including for newly considered precursors such as isoprene, is explored in this work. Theoretical and field studies are employed to: 1) identify MW-building reactions that may contribute to SOA formation in the atmosphere, 2) identify MW-building reaction products in ambient samples, and 3) parameterize atmospheric SOA formation by MW-building reactions of biogenic oxidation products. Likely reactions of biogenic oxidation products include ester, amide, and peroxyhemiacetal formation. Each of the proposed reactions involves known oxidation productions of biogenic precursors (e.g., carboxylic acids and aldehydes) reacting with one another and/or other atmospheric constituents (e.g., sulfuric acid and ammonia) to form higher-MW/lower-volatility products that can condense to form SOA. It has been suggested that products of MW-building reactions can revert to the parent reactants during sampling and analysis. Thus, relatively volatile compounds detected in ambient particle samples in fact may be decomposition products of higher-MW products. The contribution of relatively volatile biogenic oxidation products to SOA via ester, amide, and peroxyhemiacetal formation, as determined by studies based on fundamental thermodynamics and gas/particle partitioning theory, will be discussed; in addition to

  3. Package Holds Five Monolithic Microwave Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Mysoor, Narayan R.; Decker, D. Richard; Olson, Hilding M.

    1996-01-01

    Packages protect and hold monolithic microwave integrated circuit (MMIC) chips while providing dc and radio-frequency (RF) electrical connections for chips undergoing development. Required to be compact, lightweight, and rugged. Designed to minimize undesired resonances, reflections, losses, and impedance mismatches.

  4. Quasi-monolithic tunable optical resonator

    NASA Technical Reports Server (NTRS)

    Arbore, Mark (Inventor); Tapos, Francisc (Inventor)

    2003-01-01

    An optical resonator has a piezoelectric element attached to a quasi-monolithic structure. The quasi-monolithic structure defines an optical path. Mirrors attached to the structure deflect light along the optical path. The piezoelectric element controllably strains the quasi-monolithic structure to change a length of the optical path by about 1 micron. A first feedback loop coupled to the piezoelectric element provides fine control over the cavity length. The resonator may include a thermally actuated spacer attached to the cavity and a mirror attached to the spacer. The thermally actuated spacer adjusts the cavity length by up to about 20 microns. A second feedback loop coupled to the sensor and heater provides a coarse control over the cavity length. An alternative embodiment provides a quasi-monolithic optical parametric oscillator (OPO). This embodiment includes a non-linear optical element within the resonator cavity along the optical path. Such an OPO configuration is broadly tunable and capable of mode-hop free operation for periods of 24 hours or more.

  5. Constant capacitance in nanopores of carbon monoliths.

    PubMed

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  6. Secondary formation of disinfection by-products by UV treatment of swimming pool water.

    PubMed

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M S; Andersen, Henrik R

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  7. Biofilm formation and lipopeptide antibiotic iturin A production in different peptone media.

    PubMed

    Zohora, Umme Salma; Rahman, Mohammad Shahedur; Ano, Takashi

    2009-01-01

    Biofilm fermentation is a newly developed promising technique in fermentation technology. In this study no.3 and no.3S media have been used for the lipopeptide antibiotic iturin A production by Bacillus subtilis RB14. The main component of no.3 and no.3S media is Polypepton and Polypepton S, respectively. B. subtilis RB14 produces thick stable biofilm and high amount of iturin A in no.3S medium. Whereas, impaired biofilm formation and lower iturin A production was observed in no.3 medium. From the analytical information it was observed that the amounts of metal ions, such as K(+), Ca(2+) and Mn(2+), cysteine and cellulose are lower in Polypepton compared to the Polypepton S. To investigate their effect on biofilm formation and iturin A production cysteine, cellulose, K(+), Ca(2+) and Mn(2+) were added respectively into the no.3 medium at similar amount that Polypepton S contains. It was observed that individual addition of K(+), Ca(2+), cysteine and cellulose had no effect on biofilm formation, cellular growth induction or iturin A production. However, when Mn(2+) was supplemented in no.3 medium, biofilm development was restored with an improved production of iturin A. Finally, combined addition of investigated substances into the no.3 medium resulted with highly folded, thick biofilm with high cellular growth and iturin A production compared to the original no.3 medium.

  8. Influence of glucose concentrations on biofilm formation, motility, exoprotease production, and quorum sensing in Aeromonas hydrophila.

    PubMed

    Jahid, Iqbal Kabir; Lee, Na-Young; Kim, Anna; Ha, Sang-Do

    2013-02-01

    Aeromonas hydrophila recently has received increased attention because it is opportunistic and a primary human pathogen. A. hydrophila biofilm formation and its control are a major concern for food safety because biofilms are related to virulence. Therefore, we investigated biofilm formation, motility inhibition, quorum sensing, and exoprotease production of this opportunistic pathogen in response to various glucose concentrations from 0.05 to 2.5% (wt/vol). More than 0.05% glucose significantly impaired (P < 0.05) quorum sensing, biofilm formation, protease production, and swarming and swimming motility, whereas bacteria treated with 0.05% glucose had activity similar to that of the control (0% glucose). A stage shift biofilm assay revealed that the addition of glucose (2.5%) inhibited initial biofilm formation but not later stages. However, addition of quorum sensing molecules N-3-butanoyl-DL-homoserine lactone and N-3-hexanoyl homoserine lactone partially restored protease production, indicating that quorum sensing is controlled by glucose concentrations. Thus, glucose present in food or added as a preservative could regulate acyl-homoserine lactone quorum sensing molecules, which mediate biofilm formation and virulence in A. hydrophila.

  9. Engineering Hydrogen Gas Production from Formate in a Hyperthermophile by Heterologous Production of an 18-Subunit Membrane-bound Complex*

    PubMed Central

    Lipscomb, Gina L.; Schut, Gerrit J.; Thorgersen, Michael P.; Nixon, William J.; Kelly, Robert M.; Adams, Michael W. W.

    2014-01-01

    Biohydrogen gas has enormous potential as a source of reductant for the microbial production of biofuels, but its low solubility and poor gas mass transfer rates are limiting factors. These limitations could be circumvented by engineering biofuel production in microorganisms that are also capable of generating H2 from highly soluble chemicals such as formate, which can function as an electron donor. Herein, the model hyperthermophile, Pyrococcus furiosus, which grows optimally near 100 °C by fermenting sugars to produce H2, has been engineered to also efficiently convert formate to H2. Using a bacterial artificial chromosome vector, the 16.9-kb 18-gene cluster encoding the membrane-bound, respiratory formate hydrogen lyase complex of Thermococcus onnurineus was inserted into the P. furiosus chromosome and expressed as a functional unit. This enabled P. furiosus to utilize formate as well as sugars as an H2 source and to do so at both 80° and 95 °C, near the optimum growth temperature of the donor (T. onnurineus) and engineered host (P. furiosus), respectively. This accomplishment also demonstrates the versatility of P. furiosus for metabolic engineering applications. PMID:24318960

  10. THE EFFECTS OF COMBINED OZONATION AND FILTRATION ON DISINFECTION BY-PRODUCT FORMATION. (R830908)

    EPA Science Inventory

    The effects of combined ozonation and membrane filtration on the removal of the natural organic matter (NOM) and the formation of disinfection by-products (DBPs) were investigated. Ozonation/filtration resulted in a reduction of up to 50% in the dissolved organic carbon (DOC) ...

  11. THE OZONE REACTION WITH BUTADIENE: FORMATION OF TOXIC PRODUCTS. (R826236)

    EPA Science Inventory

    Abstract

    The formation yields of acrolein, 1,2-epoxy-3-butene and OH radicals have been measured from reaction of ozone with 1,3-butadiene at room temperature and atmosphere pressure. 1,3,5-Trimethyl benzene was added to scavenge OH radicals in measurements of product ...

  12. Standard enthalpies of formation for glycyl-tyrosine and products of its dissociation in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Kochergina, L. A.; Badelin, V. G.; Krutova, O. N.; Volkov, A. V.; Damrina, K. V.

    2015-07-01

    The enthalpies of solution of crystalline glycyl-tyrosine in water and potassium hydroxide aqueous solutions are determined at 298.15 K by means of direct calorimetry. Standard enthalpies of formation for dipeptide and its products of dissociation in an aqueous solution are calculated.

  13. Impact of Product Involvement, Message Format, and Receiver Sex on the Efficacy of Comparative Advertising Messages.

    ERIC Educational Resources Information Center

    Pfau, Michael

    1994-01-01

    Investigates the role and impact of receiver involvement in product class, comparative message format, and receiver sex on the relative effectiveness of comparative advertising messages. Indicates that females and males respond uniquely to comparative advertising, revealing consistent patterns regarding both circumstances and approaches. (SR)

  14. Nanoparticle-Directed Metal-Organic Framework/Porous Organic Polymer Monolithic Supports for Flow-Based Applications.

    PubMed

    Darder, María Del Mar; Salehinia, Shima; Parra, José B; Herrero-Martinez, José M; Svec, Frantisek; Cerdà, Víctor; Turnes Palomino, Gemma; Maya, Fernando

    2017-01-18

    A two-step nanoparticle-directed route for the preparation of macroporous polymer monoliths for which the pore surface is covered with a metal-organic framework (MOF) coating has been developed to facilitate the use of MOFs in flow-based applications. The flow-through monolithic matrix was prepared in a column format from a polymerization mixture containing ZnO-nanoparticles. These nanoparticles embedded in the precursor monolith were converted to MOF coatings via the dissolution-precipitation equilibrium after filling the pores of the monolith with a solution of the organic linker. Pore surface coverage with the microporous zeolitic imidazolate framework ZIF-8 resulted in an increase in surface area from 72 to 273 m(2) g(-1). Monolithic polymer containing ZIF-8 coating was implemented as a microreactor catalyzing the Knoevenagel condensation reaction and also in extraction column format enabling the preconcentration of trace levels of toxic chlorophenols in environmental waters. Our approach can be readily adapted to other polymers and MOFs thus enabling development of systems for flow-based MOF applications.

  15. Modeling of microbial substrate conversion, growth and product formation in a recycling fermentor.

    PubMed

    van Verseveld, H W; de Hollander, J A; Frankena, J; Braster, M; Leeuwerik, F J; Stouthamer, A H

    1986-01-01

    Paracoccus denitrificans and Bacillus licheniformis were grown in a carbon- and energy source-limited recycling fermentor with 100% biomass feedback. Experimental data for biomass accumulation and product formation as well as rates of carbon dioxide evolution and oxygen consumption were used in a parameter optimization procedure. This procedure was applied on a model which describes biomass growth as a linear function of the substrate consumption rate and the rate of product formation as a linear function of the biomass growth rate. The fitting procedure yielded two growth domains for P. denitrificans. In the first domain the values for the maximal growth yield and the maintenance coefficient were identical to those found in a series of chemostat experiments. The second domain could be described best with linear biomass increase, which is equal to a constant growth yield. Experimental data of a protease producing B. licheniformis also yielded two growth domains via the fitting procedure. Again, in the first domain, maximal growth yield and maintenance requirements were not significantly different from those derived from a series of chemostat experiments. Domain 2 behaviour was different from that observed with P. denitrificans. Product formation halts and more glucose becomes available for biomass formation, and consequently the specific growth rate increases in the shift from domain 1 to 2. It is concluded that for many industrial production processes, it is important to select organisms on the basis of a low maintenance coefficient and a high basic production of the desired product. It seems less important that the maximal production becomes optimized, which is the basis of most selection procedures.

  16. Production of antibacterial compounds and biofilm formation by Roseobacter species are influenced by culture conditions.

    PubMed

    Bruhn, Jesper Bartholin; Gram, Lone; Belas, Robert

    2007-01-01

    Bacterial communities associated with marine algae are often dominated by members of the Roseobacter clade, and in the present study, we describe Roseobacter phenotypes that may provide this group of bacteria with selective advantages when colonizing this niche. Nine of 14 members of the Roseobacter clade, of which half were isolated from cultures of the dinoflagellate Pfiesteria piscicida, produced antibacterial compounds. Many non-Roseobacter marine bacteria were inhibited by sterile filtered supernatants of Silicibacter sp. TM1040 and Phaeobacter (formerly Roseobacter) strain 27-4, which had the highest production of antibacterial compound. In contrast, Roseobacter strains were susceptible only when exposed to concentrated compound. The production of antibacterial compound was influenced by the growth conditions, as production was most pronounced when bacteria were grown in liquid medium under static conditions. Under these conditions, Silicibacter sp. TM1040 cells attached to one another, forming rosettes, as has previously been reported for Phaeobacter 27-4. A spontaneous Phaeobacter 27-4 mutant unable to form rosettes was also defective in biofilm formation and the production of antibacterial compound, indicating a possible link between these phenotypes. Rosette formation was observed in 8 of 14 Roseobacter clade strains examined and was very pronounced under static growth in 5 of these strains. Attachment to surfaces and biofilm formation at the air-liquid interface by these five strains was greatly facilitated by growth conditions that favored rosette formation, and rosette-forming strains were 13 to 30 times more efficient in attaching to glass compared to strains under conditions where rosette formation was not pronounced. We hypothesize that the ability to produce antibacterial compounds that principally inhibit non-Roseobacter species, combined with an enhancement in biofilm formation, may give members of the Roseobacter clade a selective advantage and

  17. Formation of disinfection by-products after pre-oxidation with chlorine dioxide or ferrate.

    PubMed

    Yang, Xin; Guo, Wanhong; Zhang, Xing; Chen, Feng; Ye, Tingjin; Liu, Wei

    2013-10-01

    The effect of pre-oxidation with chlorine dioxide (ClO2) or ferrate (Fe(VI)) on the formation of disinfection by-products (DBPs) during chlorination or chloramination was tested with natural waters from 12 sources (9 surface waters, 1 groundwater, and 2 wastewater effluents). DBPs investigated included trihalomethanes (THM), chloral hydrate (CH), haloketones (HK), haloacetonitriles (HAN) and trichloronitromethane (TCNM), chlorite and chlorate. Chlorite and chlorate were found in the ClO2-treated waters. Application of 1 mg/L ClO2 ahead of chlorination reduced the formation potential for THM by up to 45% and the formation of HK, HAN and TCNM in most of the samples. The CH formation results were mixed. The formation of CH and HK was enhanced with low doses of Fe(VI) (1 mg/L as Fe), but was greatly reduced at higher doses (20 mg/L Fe). Fe(VI) reduced the formation of THM, HAN and TCNM in most of the samples. Reduced potential for the formation of NDMA was observed in most of the samples after both ClO2 and Fe(VI) pre-oxidation.

  18. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process.

    PubMed

    Wang, Ding; Bolton, James R; Andrews, Susan A; Hofmann, Ron

    2015-06-15

    Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an advanced oxidation process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).

  19. Influence of the nitrogen source on Saccharomyces cerevisiae anaerobic growth and product formation.

    PubMed

    Albers, E; Larsson, C; Lidén, G; Niklasson, C; Gustafsson, L

    1996-09-01

    To prevent the loss of raw material in ethanol production by anaerobic yeast cultures, glycerol formation has to be reduced. In theory, this may be done by providing the yeast with amino acids, since the de novo cell synthesis of amino acids from glucose and ammonia gives rise to a surplus of NADH, which has to be reoxidized by the formation of glycerol. An industrial strain of Saccharomyces cerevisiae was cultivated in batch cultures with different nitrogen sources, i.e., ammonium salt, glutamic acid, and a mixture of amino acids, with 20 g of glucose per liter as the carbon and energy source. The effects of the nitrogen source on metabolite formation, growth, and cell composition were measured. The glycerol yields obtained with glutamic acid (0.17 mol/mol of glucose) or with the mixture of amino acids (0.10 mol/mol) as a nitrogen source were clearly lower than those for ammonium-grown cultures (0.21 mol/mol). In addition, the ethanol yield increased for growth on both glutamic acid (by 9%) and the mixture of amino acids (by 14%). Glutamic acid has a large influence on the formation of products; the production of, for example, alpha-ketoglutaric acid, succinic acid, and acetic acid, increased compared with their production with the other nitrogen sources. Cultures grown on amino acids have a higher specific growth rate (0.52 h-1) than cultures of both ammonium-grown (0.45 h-1) and glutamic acid-grown (0.33 h-1) cells. Although the product yields differed, similar compositions of the cells were attained. The NADH produced in the amino acid, RNA, and extracellular metabolite syntheses was calculated together with the corresponding glycerol formation. The lower-range values of the theoretically calculated yields of glycerol were in good agreement with the experimental yields, which may indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential.

  20. Tight gas sand production from the Almond Formation, Washakie Basin, Wyoming

    SciTech Connect

    Iverson, W.P.; Surdam, R.C.

    1995-12-31

    Gas production from the Almond Formation in the Standard Draw trend can only be accounted for by draining numerous layers of tight gas sands via the permeable upper bar sand. Discovery of this field originally focused upon production from this bar sand. But continued development cannot be explained simply by considering depletion of a 30 foot sand. Gas volumetrics verify the need to include lower sands in reservoir analysis. Core obtained from the Almond bar sand confirm petrophysical constants used in the authors` models. Their results imply that economic levels of gas production should be possible wherever a similar horizontal conduit can be tied into gas saturated layers through massive hydraulic fracturing.

  1. Formation and evolution of molecular products in α-pinene secondary organic aerosol.

    PubMed

    Zhang, Xuan; McVay, Renee C; Huang, Dan D; Dalleska, Nathan F; Aumont, Bernard; Flagan, Richard C; Seinfeld, John H

    2015-11-17

    Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58-72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA.

  2. Formation and evolution of molecular products in α-pinene secondary organic aerosol

    PubMed Central

    Zhang, Xuan; McVay, Renee C.; Huang, Dan D.; Dalleska, Nathan F.; Aumont, Bernard; Flagan, Richard C.; Seinfeld, John H.

    2015-01-01

    Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58–72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA. PMID:26578760

  3. Modeling the formation of the quench product in municipal solid waste incineration (MSWI) bottom ash.

    PubMed

    Inkaew, Kanawut; Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki

    2016-06-01

    This study investigated changes in bottom ash morphology and mineralogy under lab-scale quenching conditions. The main purpose was to clarify the mechanisms behind the formation of the quench product/layer around bottom ash particles. In the experiments, the unquenched bottom ashes were heated to 300°C for 1h, and were quenched by warm water (65°C) with different simulated conditions. After having filtered and dried, the ashes were analyzed by a combination of methodologies namely, particle size distribution analysis, intact particle and thin-section observation, X-ray diffractometry, and scanning electron microscope with energy dispersive X-ray spectroscopy. The results indicated that after quenching, the morphology and mineralogy of the bottom ash changed significantly. The freshly quenched bottom ash was dominated by a quench product that was characterized by amorphous and microcrystalline calcium-silicate-hydrate (CSH) phases. This product also enclosed tiny minerals, glasses, ceramics, metals, and organic materials. The dominant mineral phases produced by quenching process and detected by XRD were calcite, Friedel's salt, hydrocalumite and portlandite. The formation of quench product was controlled by the fine fraction of the bottom ash (particle size <0.425mm). From the observations, a conceptual model of the ash-water reactions and formation of the quench product in the bottom ash was proposed.

  4. Formation of naturally occurring pigments during the production of nitrite-free dry fermented sausages.

    PubMed

    De Maere, Hannelore; Fraeye, Ilse; De Mey, Eveline; Dewulf, Lore; Michiels, Chris; Paelinck, Hubert; Chollet, Sylvie

    2016-04-01

    This study investigates the potential of producing red coloured dry fermented sausages without the addition of nitrite and/or nitrate. Therefore, the formation of zinc protoporphyrin IX (Zn(II)PPIX) as naturally occurring pigment, and the interrelated protoporphyrin IX (PPIX) and heme content were evaluated during nitrite-free dry fermented sausage production at different pH conditions. Zn(II)PPIX was only able to form in dry fermented sausages at pH conditions higher than approximately 4.9. Additionally, the presence of Zn(II)PPIX increased drastically at the later phase of the production process (up to day 177), confirming that in addition to pH, time is also a crucial factor for its formation. Similarly, PPIX also accumulated in the meat products at increased pH conditions and production times. In contrast, a breakdown of heme was observed. This breakdown was more gradual and independent of pH and showed no clear relationship with the formed amounts of Zn(II)PPIX and PPIX. A statistically significant relationship between Zn(II)PPIX formation and product redness was established.

  5. SU8 diaphragm micropump with monolithically integrated cantilever check valves.

    PubMed

    Ezkerra, Aitor; Fernández, Luis José; Mayora, Kepa; Ruano-López, Jesús Miguel

    2011-10-07

    This paper presents a SU8 unidirectional diaphragm micropump with embedded out-of-plane cantilever check valves. The device represents a reliable and low-cost solution for integration of microfluidic control in lab-on-a-chip devices. Its planar architecture allows monolithic definition of its components in a single step and potential integration with previously reported PCR, electrophoresis and flow-sensing SU8 microdevices. Pneumatic actuation is applied on a PDMS diaphragm, which is bonded to the SU8 body at wafer level, further enhancing its integration and mass production capabilities. The cantilever check valves move synchronously with the diaphragm, feature fast response (10ms), low dead volume (86nl) and a 94% flow blockage up to 300kPa. The micropump achieves a maximum flow rate of 177 μl min(-1) at 6 Hz and 200 kPa with an effective area of 10 mm(2). The device is reliable, self-priming and tolerant to particles and big bubbles. To the knowledge of the authors, this is the first micropump in SU8 with monolithically integrated cantilever check valves.

  6. The market of huge monolithic mirror substrates for optical astronomy

    NASA Astrophysics Data System (ADS)

    Döhring, Thorsten

    2013-09-01

    Professional astronomical telescopes are complex optical systems at the limit of technical feasibility. Often monolithic primary mirrors and sometimes even secondary mirrors with huge dimensions are used. Prominent examples are the two reflectors of the Large Binocular Telescope and the giant mirrors of VLT, GEMINI, and SUBARU. The performance of such precision optical components significantly depends on the physical parameters and the quality of their substrate materials. Within this paper selection criteria for mirror substrates will be discussed, thereby considering the important technical parameters as well as commercial points and aspects of project management. Qualities and limitations of classical mirror substrate materials like Zerodur, ULE, Sitall, borosilicate glass and Cervit will be evaluated and compared to new substrate materials like silicon carbide and beryllium. The different suppliers and their production processes are presented. In addition large mirrors of existing observatories and of telescopes under construction will be listed, thereby concentrating on mirrors above three meter in diameter. An outlook on material trends and on future astronomical telescopes closes this overview on the market of huge monolithic mirror substrates for optical astronomy.

  7. Drinking Water Disinfection by In-line Electrolysis: Product and Inorganic By-Product Formation

    NASA Astrophysics Data System (ADS)

    Bergmann, M. E. Henry

    This section covers peculiarities of so-called in-line electrolysis when drinking water is electrolysed to produce disinfection species killing microorganisms. Mainly mixed oxide electrodes (MIO) based on IrO2 and/or RuO2 coatings and boron-doped diamond electrodes were used in the studies. Artificial and real drinking water systems were electrolysed in continuous and discontinuous operating mode, varying water composition, current density and electrode materials. Results show, besides the ability of producing active chlorine, risks of inorganic disinfection by-products (DBPs) such as chlorate, perchlorate, nitrite, ammonium, chloramines, hydrogen peroxide and others. DBPs are responsible for analysis errors using DPD method for active chlorine measurements. Geometry may influence by-product yield. As a conclusion, the necessity of developing test routines for practical cell applications must be underlined.

  8. Biofilm Formation and β-Lactamase Production in Burn Isolates of Pseudomonas aeruginosa

    PubMed Central

    Heydari, Samira; Eftekhar, Fereshteh

    2015-01-01

    Background: Pseudomonas aeruginosa is an important nosocomial pathogen characterized by its innate resistance to multiple antimicrobial agents. Plasmid-mediated drug resistance also occurs by the production of extended-spectrum β-lactamases (ESBL), metallo β-lactamases (MBL), and AmpC β-lactamases. Another important factor for establishment of chronic infections by P. aeruginosa is biofilm formation mediated by the psl gene cluster. Objectives: The aim of this study was to evaluate biofilm formation and presence of the pslA gene in burn isolates of P. aeruginosa as well as the association of antibiotic resistance, MBL, ESBL and AmpC β-lactamase production with biofilm formation among the isolates. Materials and Methods: Sixty-two burn isolates of P. aeruginosa were obtained from Shahid Motahari Hospital in Tehran from August to October 2011. Antibiotic susceptibility was determined by the disc diffusion assay. MBL, AmpC and ESBL production were screened using the double disc synergy test, AmpC disc test and combined disc diffusion assay, respectively. The potential to form biofilm was measured using the microtiter plate assay and pslA gene was detected using specific primers and PCR. Results: Biofilm formation was observed in 43.5% of the isolates, of which 66.7% produced strong and 33.3% formed weak biofilms. All biofilm-positive and 14.2% of biofilm-negative isolates harbored the pslA gene. MBL, AmpC and ESBL production were significantly higher in the biofilm-positive isolates (70.3%, 62.9% and 33.3%, respectively) compared to the biofilm-negative strains (31.4%, 34.2% and 20%, respectively). Overall, 19 isolates (30.6%) co-produced MBL and AmpC, among which the majority were biofilm-positive (63.1%). Finally, four isolates (6.4%) had all three enzymes, of which 3 (75%) produced biofilm. Conclusions: Biofilm formation (both strong and weak) strongly correlated with pslA gene carriage. Biofilm formation also correlated with MBL and AmpC

  9. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    SciTech Connect

    K.C. Kwon

    2009-09-30

    of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash coat, and catalytic metals, to develop a regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor. The task of developing kinetic rate equations and modeling the direct oxidation process to assist in the design of large-scale plants will be abandoned since formulation of catalysts suitable for the removal of H{sub 2}S and COS is being in progress. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 46-570 seconds under reaction conditions to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases and evaluate their capabilities in reducing hydrogen sulfide and COS in coal gases. Simulated coal gas mixtures consist of 3,200-4,000-ppmv hydrogen sulfide, 1,600-20,000-ppmv sulfur dioxide, 18-27 v% hydrogen, 29-41 v% CO, 8-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of simulated coal gas mixtures to the reactor are 30 - 180 cm{sup 3}/min at 1 atm and 25 C (SCCM). The temperature of the reactor is controlled in

  10. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    SciTech Connect

    K. C. Kwon

    2007-09-30

    of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 130-156 seconds at 120-140 C to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases, evaluate removal capabilities of hydrogen sulfide and COS from coal gases with formulated catalysts, and develop an economic regeneration method of deactivated catalysts. Simulated coal gas mixtures consist of 3,300-3,800-ppmv hydrogen sulfide, 1,600-1,900 ppmv sulfur dioxide, 18-21 v% hydrogen, 29-34 v% CO, 8-10 v% CO{sub 2}, 5-18 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 114-132 SCCM. The temperature of the reactor is controlled in an oven at 120-140 C. The pressure of the reactor is maintained

  11. Formation of N-nitrosodimethylamine (NDMA) from reaction of monochloramine: a new disinfection by-product.

    PubMed

    Choi, Junghoon; Valentine, Richard L

    2002-02-01

    Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed from the reaction between DMA and monochloramine indicating that it should be considered a potential disinfection by-product. The formation of NDMA increased with increased monochloramine concentration and showed maximum in yield when DMA was varied at fixed monochloramine concentrations. The mass spectra of the NDMA formed from DMA and 15N isotope labeled monochloramine (15NH2Cl) showed that the source of one of the nitrogen atoms in the nitroso group in NDMA was from monochloramine. Addition of 0.05 and 0.5 mM of preformed monochloramine to a secondarily treated wastewater at pH 7.2 also resulted in the formation of 3.6 and 111 ng/L of NDMA, respectively, showing that this is indeed an environmentally relevant NDMA formation pathway. The proposed NDMA formation mechanism consists of (i) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (ii) the oxidation of UDMH by monochloramine to NDMA, and (iii) the reversible chlorine transfer reaction between monochloramine and DMA which is parallel to (i). We conclude that reactions involving monochloramine in addition to classical nitrosation reactions are potentially important pathways for NDMA formation.

  12. Thermodynamics of formate-oxidizing metabolism and implications for H2 production.

    PubMed

    Lim, Jae Kyu; Bae, Seung Seob; Kim, Tae Wan; Lee, Jung-Hyun; Lee, Hyun Sook; Kang, Sung Gyun

    2012-10-01

    Formate-dependent proton reduction to H(2) (HCOO(-) + H(2)O → HCO(3)(-) + H(2)) has been reported for hyperthermophilic Thermococcus strains. In this study, a hyperthermophilic archaeon, Thermococcus onnurineus strain NA1, yielded H(2) accumulation to a partial pressure of 1 × 10(5) to 7 × 10(5) Pa until the values of Gibbs free energy change (ΔG) reached near thermodynamic equilibrium (-1 to -3 kJ mol(-1)). The bioenergetic requirement for the metabolism to conserve energy was demonstrated by ΔG values as small as -5 kJ mol(-1), which are less than the biological minimum energy quantum, -20 kJ mol(-1), as calculated by Schink (B. Schink, Microbiol. Mol. Biol. Rev. 61:262-280, 1997). Considering formate as a possible H(2) storage material, the H(2) production potential of the strain was assessed. The volumetric H(2) production rate increased linearly with increasing cell density, leading to 2,820 mmol liter(-1) h(-1) at an optical density at 600 nm (OD(600)) of 18.6, and resulted in the high specific H(2) production rates of 404 ± 6 mmol g(-1) h(-1). The H(2) productivity indicates the great potential of T. onnurineus strain NA1 for practical application in comparison with H(2)-producing microbes. Our result demonstrates that T. onnurineus strain NA1 has a highly efficient metabolic system to thrive on formate in hydrothermal systems.

  13. Molecularly imprinted monolith coupled on-line with high performance liquid chromatography for simultaneous quantitative determination of cyromazine and melamine.

    PubMed

    Wang, Shanshan; Li, Daomin; Hua, Zhendong; Zhao, Meiping

    2011-09-21

    We report a novel method for simultaneous determination of cyromazine and melamine based on a molecularly imprinted monolith on-line coupled with high performance liquid chromatography (HPLC). The imprinted monolith was prepared by in situ polymerization using 2,4-diamino-6-undecyl-1,3,5-triazine (DAUTA) as a mimic template. Due to the better solubility of DAUTA in chloroform, hydrogen bonds were effectively developed between the template and the functional monomer and resulted in the formation of highly specific cavities in the obtained imprinted monolith. With methanol as the loading solvent, cyromazine and melamine were both selectively retained by the obtained imprinted monolith, while the nonspecific adsorption on the non-imprinted monolith was negligible. The imprinted monolithic column was on-line coupled with HPLC for purification and concentration of the two analytes from milk samples. To minimize the peak broadening during the on-line transfer of the analytes from the imprinted monolith to the following analytical column, a successive desorption program was developed for the elution step, which enabled on-line stacking of the target compounds before being analyzed by HPLC. Low detection limits of 0.12 μg mL(-1) for melamine and 0.05 μg mL(-1) for cyromazine were achieved with only 0.3 mL of milk sample and a low sensitivity HPLC-UVD instrument. The method may be further extended to detect other analytes of interest in a large variety of samples.

  14. Project Selection in Monolithic Organizations.

    DTIC Science & Technology

    1974-08-01

    Financing in Canada. University of Western (June 1973) Ontario. 4. Blair Little School of Business The Assessment of Markets for the R.G. Cooper...Sp~cialement des Entreprises Utilisant des Techniques de Production Avancies. (dfcembre 1973) 17. I. Vertinsky Fac~lty of Commerce and Project...P.J. Halpern Studies, University of by Forest Products Industries. Toronto. (Nay 1975) 30. J.C.T. Nko Faculty of Commerce and Venture Capital Financing

  15. Engineering the productivity of recombinant Escherichia coli for limonene formation from glycerol in minimal media.

    PubMed

    Willrodt, Christian; David, Christian; Cornelissen, Sjef; Bühler, Bruno; Julsing, Mattijs K; Schmid, Andreas

    2014-08-01

    The efficiency and productivity of cellular biocatalysts play a key role in the industrial synthesis of fine and bulk chemicals. This study focuses on optimizing the synthesis of (S)-limonene from glycerol and glucose as carbon sources using recombinant Escherichia coli. The cyclic monoterpene limonene is extensively used in the fragrance, food, and cosmetic industries. Recently, limonene also gained interest as alternative jet fuel of biological origin. Key parameters that limit the (S)-limonene yield, related to genetics, physiology, and reaction engineering, were identified. The growth-dependent production of (S)-limonene was shown for the first time in minimal media. E. coli BL21 (DE3) was chosen as the preferred host strain, as it showed low acetate formation, fast growth, and high productivity. A two-liquid phase fed-batch fermentation with glucose as the sole carbon and energy source resulted in the formation of 700 mg L(org) (-1) (S)-limonene. Specific activities of 75 mU g(cdw) (-1) were reached, but decreased relatively quickly. The use of glycerol as a carbon source resulted in a prolonged growth and production phase (specific activities of ≥50 mU g(cdw) (-1) ) leading to a final (S)-limonene concentration of 2,700 mg L(org) (-1) . Although geranyl diphosphate (GPP) synthase had a low solubility, its availability appeared not to limit (S)-limonene formation in vivo under the conditions investigated. GPP rerouting towards endogenous farnesyl diphosphate (FPP) formation also did not limit (S)-limonene production. The two-liquid phase fed-batch setup led to the highest monoterpene concentration obtained with a recombinant microbial biocatalyst to date.

  16. Feasibility of Formation of AZS (Alumina-Zirconia-Silica) Refractory Products with Different Composition to the Commercial Product Through X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Guzmán, A. M.; Rodríguez, P.

    The AZS refractory materials with different composition to the commercial product were obtained, and the feasibility of formation of these products was studied taking like departure point the free energy of their formation. The AZS refractories were obtained by a traditional method of producing ceramic materials, the process of sintering.

  17. A monolithic integrated photonic microwave filter

    NASA Astrophysics Data System (ADS)

    Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

    2016-12-01

    Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

  18. Monolithic mode-locked quantum dot lasers

    NASA Astrophysics Data System (ADS)

    Penty, R. V.; Thompson, M. G.; White, I. H.

    2008-02-01

    Monolithic mode-locked laser diodes based on QD active regions are regarded as potentially suitable for a large range of photonic applications due to their compactness, mechanical stability and robustness, high potential repetition rates and low potential jitter. Their inherent properties, such as high differential gain, low chirp and fast saturable absorption have led to demonstration of improved performance over their QW equivalents. Low background loss and the relatively long lengths of quantum dot laser devices also have encouraged studies of mode-locking at repetition rates previously not explored in monolithic devices. Applications include biomedicine, high-speed data transmission, clock signal generation and electro-optic sampling. This paper reviews some of the work at Cambridge on the realization of such devices.

  19. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2016-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  20. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2015-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  1. Comparison of soil-monolith extraction techniques

    NASA Astrophysics Data System (ADS)

    Meissner, R.; Rupp, H.; Weller, U.; Vogel, H.-J.

    2009-04-01

    In the international literature the term „lysimeter" is used for different objectives, e.g. suction cups, fluxmeters, etc. According to our understanding it belongs to the direct methods to measure water and solute fluxes in soil. Depending on the scientific task the shape and dimensions of the lysimeter as well as the type of filling (disturbed or undisturbed) and the specific instrumentation can be different. In any case where water dynamics or solute transport in natural soil is considered, lysimeters should be filled with 'undisturbed' monoliths which are large enough to contain the small scale heterogeneity of a site since flow and transport is highly sensitive to soil structure. Furthermore, lysimeters with vegetation should represent the natural crop inventory and the maximum root penetration depth should be taken into account. The aim of this contribution is to give an overview about different methods for obtaining undisturbed soil monoliths, in particular about i) techniques for the vertical and ii) for the horizontal extraction and iii) to evaluate the most frequently used procedures based on X-ray tomography images. Minimal disturbance of the soil monolith during extraction and subsequence filling of the lysimeter vessel is of critical importance for establishing flow and transport conditions corresponding approximately to natural field conditions. In the past, several methods were used to extract and fill lysimeter vessels vertically - including hand digging, employing sets of trihedral scaffold with lifting blocks and ballast, or using heavy duty excavators, which could shear and cut large blocks of soil. More recently, technologies have been developed to extract cylindrical soil monoliths by using ramming equipment or screw presses. One of the great disadvantages of the mentioned methods is the compaction or settling of soil that occurs during the "hammering" or "pressing". For this reason a new technology was developed, which cuts the outline of

  2. Polymethacrylate monoliths with immobilized poly-3-mercaptopropyl methylsiloxane film for high-coverage surface functionalization by thiol-ene click reaction.

    PubMed

    Carrasco-Correa, Enrique Javier; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel; Lämmerhofer, Michael

    2014-11-07

    In this work, new polythiol-functionalized macroporous monolithic polymethacrylate-polysiloxane composite materials are presented which can be useful substrates for highly efficient immobilization of (chiral) catalysts, chromatographic ligands, and other functional moieties by thiol-ene click reaction. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) (poly(GMA-co-EDMA)) monoliths were coated with a poly-3-mercaptopropyl methylsiloxane (PMPMS) film and subsequently the polymer was covalently immobilized by formation of crosslinks via nucleophilic substitution reaction with pendent 2,3-epoxypropyl groups on the monolith surface. This monolith, though, showed similar levels of surface coverage as a reference monolith obtained by opening of the epoxide groups with sodium hydrogen sulfide. However, a 3-step functionalization by amination of the epoxy monolith, followed by its vinylation with allylglycidyl ether and subsequent thiolation by coating of a thin polythiol (PMPMS) film and crosslinking by click reaction furnished a monolith with more than 2-fold elevated thiol coverage. Its further functionalization with a clickable chiral quinine carbamate selector clearly documented the benefit of highly dense thiol surfaces for such reactions and synthesis of functional materials with proper ligand loadings. The new monoliths were chromatographically tested in capillary electrochromatography mode using N-3,5-dinitrobenzoyl-leucine as chiral probe and the capillary column with the monolith having the highest selector coverage, produced from the precursor with the most thiols on the surface, showed the largest separation factor. By performic acid oxidation the surface characteristic could be tuned and strongly altered due to a delicate balance of enantioselective and non-specific interactions.

  3. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, M.W.; Coronado, P.R.; Hair, L.M.

    1995-03-07

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels. 6 figs.

  4. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, Michael W.; Coronado, Paul R.; Hair, Lucy M.

    1995-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.

  5. Ultralow Noise Monolithic Quantum Dot Photonic Oscillators

    DTIC Science & Technology

    2013-10-28

    HBCU/MI) ULTRALOW NOISE MONOLITHIC QUANTUM DOT PHOTONIC OSCILLATORS LUKE LESTER UNIVERSITY OF NEW MEXICO 10/28/2013 Final Report DISTRIBUTION A...New Mexico , Albuquerque, NM 87131-0001 Air Force Office of Scientific Research 875 N. Randolph St., Rm 3112 Arlington, VA 22203-1954 patricia.bell...Report 06/01/2010 - 05/31/2013 Professor Luke F. Lester, PI, University of New Mexico Contact address: Center for High Technology Materials

  6. Monolithically integrated interferometer for optical displacement measurement

    NASA Astrophysics Data System (ADS)

    Hofstetter, Daniel; Zappe, Hans P.

    1996-01-01

    We discuss the fabrication of a monolithically integrated optical displacement sensors using III-V semiconductor technology. The device is configured as a Michelson interferometer and consists of a distributed Bragg reflector laser, a photodetector and waveguides forming a directional coupler. Using this interferometer, displacements in the 100 nm range could be measured at distances of up to 45 cm. We present fabrication, device results and characterization of the completed interferometer, problems, limitations and future applications will also be discussed.

  7. Monolithic solid oxide fuel cell development

    NASA Technical Reports Server (NTRS)

    Myles, K. M.; Mcpheeters, C. C.

    1989-01-01

    The feasibility of the monolithic solid oxide fuel cell (MSOFC) concept has been proven, and the performance has been dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials have been minimized, thus allowing successful fabrication of the MSOFC with few defects. The MSOFC shows excellent promise for development into a practical power source for many applications from stationary power, to automobile propulsion, to space pulsed power.

  8. Monolithic Integration of Semiconductor and Superconductor Components

    DTIC Science & Technology

    1992-03-31

    change the device performance at room temperature . The monolithic bipolar transistors will be fabricated by Honeywell’s MICRO SWITCH Division of...subsequent processing run funded by Honeywell which was completed in December, 1991. Task 2.5: Device Evaluation Room temperature resistance measurements were...dc bias current of only 1 pA was measured at a substrate temperature of 73 K in a microbolometer occupying a 125 pm x 125 pm area. In thermal imaging

  9. Method for making monolithic metal oxide aerogels

    DOEpatents

    Coronado, Paul R.

    1999-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

  10. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    PubMed

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths.

  11. Rules governing the formation of photolysis products in the lead azide-copper(I) oxide system

    NASA Astrophysics Data System (ADS)

    Surovoi, E. P.; Bugerko, L. N.; Rasmatova, S. V.; Bin, S. V.

    2011-03-01

    It was found that, along with a decrease in the rate of photolysis and photocurrent in the region of lead azide intrinsic absorption, the addition of copper(I) oxide broadened the range of spectral sensitivity, and preliminary treatment of the PbN6(Ab)-Cu2O system with light (λ = 365 nm) increased the rate of photolysis. The rate constants for photolysis were estimated. An analysis of the results of current-voltage characteristic, contact potential difference, and contact photo-electromotive force measurements was used to construct a diagram of energy zones and suggest a model of the photolysis of the PbN6(Ab)-Cu2O system including stages of the generation, recombination, and redistribution of nonequilibrium carriers in a contact field, formation of microheterogeneous PbN6(Ab)-Pb (photolysis product) systems, and formation of final photolysis products.

  12. Colony formation and interleukin 2 production by leukaemic human T cells.

    PubMed Central

    Krajewski, A S; Dewar, A E; Seidelin, P H; Murray, R

    1983-01-01

    PHA-induced colony formation and interleukin 2 (IL-2) production were studied in four patients with T cell leukaemia (three cases OKT4+/T helper and one case OKT8+/T cytotoxic suppressor). Cases of T helper cell leukaemia showed colony formation that was comparable to normal purified blood T cells and was not dependent on the addition of conditioned medium, containing IL-2 activity, to cultures. In contrast the T suppressor cell leukaemia formed colonies only when cultures were supplemented with IL-2 containing medium. When IL-2 production by PHA stimulated cells was measured culture supernatants from the three T helper cell leukaemias all showed normal or high levels of activity, when compared to normal blood mononuclear cells, whereas the T suppressor cell leukaemia showed no activity. PMID:6604606

  13. FRACTURE-RESISTANT MONOLITHIC DENTAL CROWNS

    PubMed Central

    Zhang, Yu; Mai, Zhisong; Barani, Amir; Bush, Mark; Lawn, Brian

    2016-01-01

    Objective To quantify the splitting resistance of monolithic zirconia, lithium disilicate and nanoparticle-composite dental crowns. Methods Fracture experiments were conducted on anatomically-correct monolithic crown structures cemented to standard dental composite dies, by axial loading of a hard sphere placed between the cusps. The structures were observed in situ during fracture testing, and critical loads to split the structures were measured. Extended finite element modeling (XFEM), with provision for step-by-step extension of embedded cracks, was employed to simulate full failure evolution. Results Experimental measurements and XFEM predictions were self consistent within data scatter. In conjunction with a fracture mechanics equation for critical splitting load, the data were used to predict load-sustaining capacity for crowns on actual dentin substrates and for loading with a sphere of different size. Stages of crack propagation within the crown and support substrate were quantified. Zirconia crowns showed the highest fracture loads, lithium disilicate intermediate, and dental nanocomposite lowest. Dental nanocomposite crowns have comparable fracture resistance to natural enamel. Significance The results confirm that monolithic crowns are able to sustain high bite forces. The analysis indicates what material and geometrical properties are important in optimizing crown performance and longevity. PMID:26792623

  14. Regulation of product formation during glucose or lactose limitation in nongrowing cells of Streptococcus lactis.

    PubMed

    Fordyce, A M; Crow, V L; Thomas, T D

    1984-08-01

    Nongrowing cells of Streptococcus lactis in a pH-stat were dosed with sugar to allow fermentation at the maximum rate or were fed a continuous supply of sugar at rates less than the maximum. Under anaerobic conditions, rapid fermentation of either glucose or lactose was essentially homolactic. However, with strain ML3, limiting the fermentation rate diverted approximately half of the pyruvate to formate, acetate, and ethanol. At limiting glucose fermentation rates, cells contained lower concentrations of lactate dehydrogenase activator (fructose 1,6-diphosphate) and pyruvate formate-lyase inhibitors (triose phosphates). As a result, pyruvate formate-lyase and pyruvate dehydrogenase play a greater role in pyruvate metabolism. In contrast to strain ML3, strain ML8 did not give the same diversion of products under anaerobic conditions, and cells retained higher concentrations of the above effector compounds. Lactose metabolism under aerobic conditions resulted in pyruvate excretion by both S. lactis ML3 and ML8. At 7% of the maximum utilization rate, pyruvate accounted for 69 and 35% of the lactose metabolized by ML3 and ML8, respectively. Acetate was also a major product, especially with ML8. The data suggest that NADH oxidase is involved in coenzyme recycling in the presence of oxygen and that pyruvate formate-lyase is inactivated, but the pyruvate dehydrogenase complex still functions.

  15. Photooxidative degradation of beer bittering principles: product analysis with respect to lightstruck flavour formation.

    PubMed

    Huvaere, Kevin; Sinnaeve, Bart; Van Bocxlaer, Jan; De Keukeleire, Denis

    2004-09-01

    Isohumulones, the main bittering agents in beer, are decomposed by light-induced reactions, thereby leading to radical precursors on the pathway to lightstruck flavour formation. Excited flavins, formed on visible-light irradiation, readily interact with isohumulones, as well as with reduced and oxidized derivatives thereof. From identification of both volatile and non-volatile reaction products thus formed, feasible degradation mechanisms are proposed.

  16. Less common applications of monoliths III. Gas chromatography

    PubMed Central

    Svec, Frantisek; Kurganov, Alexander A.

    2008-01-01

    Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography. PMID:17645884

  17. Strength and toughness of monolithic and composite silicon nitrides

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.

    1990-01-01

    The strength and toughness of two composite and two monolithic silicon nitrides were measured from 25 to 1400 C. The monolithic and composite materials were made from similar starting powders. Both of the composite materials contained 30 vol percent silicon carbide whiskers. All measurements were made by four point flexure in surrounding air and humidity. The composite and monolithic materials exhibited similar fast fracture properties as a function of temperature.

  18. Nicorandil prevents sirolimus-induced production of reactive oxygen species, endothelial dysfunction, and thrombus formation.

    PubMed

    Aizawa, Ken; Takahari, Youko; Higashijima, Naoko; Serizawa, Kenichi; Yogo, Kenji; Ishizuka, Nobuhiko; Endo, Koichi; Fukuyama, Naoto; Hirano, Katsuya; Ishida, Hideyuki

    2015-03-01

    Sirolimus (SRL) is widely used to prevent restenosis after percutaneous coronary intervention. However, its beneficial effect is hampered by complications of thrombosis. Several studies imply that reactive oxygen species (ROS) play a critical role in endothelial dysfunction and thrombus formation. The present study investigated the protective effect of nicorandil (NIC), an anti-angina agent, on SRL-associated thrombosis. In human coronary artery endothelial cells (HCAECs), SRL stimulated ROS production, which was prevented by co-treatment with NIC. The preventive effect of NIC on ROS was abolished by 5-hydroxydecanoate but not by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. NIC also inhibited SRL-induced up-regulation of NADPH oxidase subunit p22(phox) mRNA. Co-treatment with NIC and SRL significantly up-regulated superoxide dismutase 2. NIC treatment significantly improved SRL-induced decrease in viability of HCAECs. The functional relevance of the preventive effects of NIC on SRL-induced ROS production and impairment of endothelial viability was investigated in a mouse model of thrombosis. Pretreatment with NIC inhibited the SRL-induced acceleration of FeCl3-initiated thrombus formation and ROS production in the testicular arteries of mice. In conclusion, NIC prevented SRL-induced thrombus formation, presumably due to the reduction of ROS and to endothelial protection. The therapeutic efficacy of NIC could represent an additional option in the prevention of SRL-related thrombosis.

  19. Hydroxyl radical mediates N epsilon-(carboxymethyl)lysine formation from Amadori product.

    PubMed

    Nagai, R; Ikeda, K; Higashi, T; Sano, H; Jinnouchi, Y; Araki, T; Horiuchi, S

    1997-05-08

    Recent studies demonstrated N epsilon-(carboxymethyl)lysine (CML) in several tissue proteins. Incubation of proteins with glucose leads through a Schiff base to Amadori products. Oxidative cleavage of Amadori products is considered as a major route to CML formation in vivo, whereas it is not known which reactive oxygen species (ROS) is involved. The present study is undertaken to identify such a ROS. We prepared heavily glycated human serum albumin (HSA) which contained a high level of Amadori products, but an undetectable level of CML. Incubation of glycated HSA with FeCl2, but not with H2O2, led to CML formation which was enhanced by H2O2, but inhibited by catalase or mannitol, whereas superoxide dismutase had no effect. Similar data were obtained by experiments using Boc-fructose-lysine as a model Amadori compound. These data indicate that hydroxyl radical generated by the reaction of Fe2+ with H2O2 mediates CML formation from Amadori compounds.

  20. Liquid phase products and solid deposit formation from thermally stressed model jet fuels

    NASA Technical Reports Server (NTRS)

    Kim, W. S.; Bittker, D. A.

    1984-01-01

    The relationship between solid deposit formation and liquid degradation product concentration was studied for the high temperature (400 C) stressing of three hydrocarbon model fuels. A Jet Fuel Thermal Oxidation Tester was used to simulate actual engine fuel system conditions. The effects of fuel type, dissolved oxygen concentration, and hot surface contact time (reaction time) were studied. Effects of reaction time and removal of dissolved oxygen on deposit formation were found to be different for n-dodecane and for 2-ethylnaphthalene. When ten percent tetralin is added to n-dodecane to give a simpler model of an actual jet fuel, the tetralin inhibits both the deposit formation and the degradation of n-dodecane. For 2-ethylnaphthalene primary product analyses indicate a possible self-inhibition at long reaction times of the secondary reactions which form the deposit precursors. The mechanism of the primary breakdown of these fuels is suggested and the primary products which participate in these precursor-forming reactions are identified. Some implications of the results to the thermal degradation of real jet fuels are given.

  1. Estimating the carbon sequestration capacity of shale formations using methane production rates.

    PubMed

    Tao, Zhiyuan; Clarens, Andres

    2013-10-01

    Hydraulically fractured shale formations are being developed widely for oil and gas production. They could also represent an attractive repository for permanent geologic carbon sequestration. Shales have a low permeability, but they can adsorb an appreciable amount of CO2 on fracture surfaces. Here, a computational method is proposed for estimating the CO2 sequestration capacity of a fractured shale formation and it is applied to the Marcellus shale in the eastern United States. The model is based on historical and projected CH4 production along with published data and models for CH4/CO2 sorption equilibria and kinetics. The results suggest that the Marcellus shale alone could store between 10.4 and 18.4 Gt of CO2 between now and 2030, which represents more than 50% of total U.S. CO2 emissions from stationary sources over the same period. Other shale formations with comparable pressure-temperature conditions, such as Haynesville and Barnett, could provide significant additional storage capacity. The mass transfer kinetic results indicate that injection of CO2 would proceed several times faster than production of CH4. Additional considerations not included in this model could either reinforce (e.g., leveraging of existing extraction and monitoring infrastructure) or undermine (e.g., leakage or seismicity potential) this approach, but the sequestration capacity estimated here supports continued exploration into this pathway for producing carbon neutral energy.

  2. Optimized Jasmonic Acid Production by Lasiodiplodia theobromae Reveals Formation of Valuable Plant Secondary Metabolites

    PubMed Central

    Eng, Felipe; Haroth, Sven; Feussner, Kirstin; Meldau, Dorothea; Rekhter, Dmitrij; Ischebeck, Till; Brodhun, Florian

    2016-01-01

    Jasmonic acid is a plant hormone that can be produced by the fungus Lasiodiplodia theobromae via submerged fermentation. From a biotechnological perspective jasmonic acid is a valuable feedstock as its derivatives serve as important ingredients in different cosmetic products and in the future it may be used for pharmaceutical applications. The objective of this work was to improve the production of jasmonic acid by L. theobromae strain 2334. We observed that jasmonic acid formation is dependent on the culture volume. Moreover, cultures grown in medium containing potassium nitrate as nitrogen source produced higher amounts of jasmonic acid than analogous cultures supplemented with ammonium nitrate. When cultivated under optimal conditions for jasmonic acid production, L. theobromae secreted several secondary metabolites known from plants into the medium. Among those we found 3-oxo-2-(pent-2-enyl)-cyclopentane-1-butanoic acid (OPC-4) and hydroxy-jasmonic acid derivatives, respectively, suggesting that fungal jasmonate metabolism may involve similar reaction steps as that of plants. To characterize fungal growth and jasmonic acid-formation, we established a mathematical model describing both processes. This model may form the basis of industrial upscaling attempts. Importantly, it showed that jasmonic acid-formation is not associated to fungal growth. Therefore, this finding suggests that jasmonic acid, despite its enormous amount being produced upon fungal development, serves merely as secondary metabolite. PMID:27907207

  3. The formate channel FocA exports the products of mixed-acid fermentation.

    PubMed

    Lü, Wei; Du, Juan; Schwarzer, Nikola J; Gerbig-Smentek, Elke; Einsle, Oliver; Andrade, Susana L A

    2012-08-14

    Formate is a major metabolite in the anaerobic fermentation of glucose by many enterobacteria. It is translocated across cellular membranes by the pentameric ion channel/transporter FocA that, together with the nitrite channel NirC, forms the formate/nitrite transporter (FNT) family of membrane transport proteins. Here we have carried out an electrophysiological analysis of FocA from Salmonella typhimurium to characterize the channel properties and assess its specificity toward formate and other possible permeating ions. Single-channel currents for formate, hypophosphite and nitrite revealed two mechanistically distinct modes of gating that reflect different types of structural rearrangements in the transport channel of each FocA protomer. Moreover, FocA did not conduct cations or divalent anions, but the chloride anion was identified as further transported species, along with acetate, lactate and pyruvate. Formate, acetate and lactate are major end products of anaerobic mixed-acid fermentation, the pathway where FocA is predominantly required, so that this channel is ideally adapted to act as a multifunctional export protein to prevent their intracellular accumulation. Because of the high degree of conservation in the residues forming the transport channel among FNT family members, the flexibility in conducting multiple molecules is most likely a general feature of these proteins.

  4. Influence of sclerotia formation on ligninolytic enzyme production in Morchella crassipes.

    PubMed

    Kanwal, Harpreet Kaur; Reddy, M Sudhakara

    2014-07-01

    Morels are wild edible ascomycetous mushrooms that are highly prized because of their medicinal and nutritional qualities. Ligninolytic enzymes are considered as one of the most important enzymes in fungi due to their involvement in fruiting body formation during artificial cultivation on different substrates. In the life cycle of morels, sclerotia are the intermediate stage to form a fruiting body from mycelia. We have studied the production of ligninolytic enzymes by Morchella crassipes MR8 growing on different substrates and during sclerotia formation. This fungus is able to produce ligninolytic enzymes such as laccase (Lac), lignin peroxidase (LiP), and manganese-dependent peroxidase (MnP) when grown on different substrates. Maximum Lac activity was observed when grown in wheat grains whereas maximum activities of MnP and LiP were observed when grown in rice straw. Laccase enzyme was produced in high titers during sclerotia formation and maturation when grown in combinations of soil and substrates. A large number of sclerotia was observed in soil and wheat grains, along with high titers of laccase. Cellulase activity was observed to be constant during sclerotia formation and maturation. The present study results suggest that laccase enzyme might play an important role in sclerotia formation in morels.

  5. Monolithic Lumped Element Integrated Circuit (M2LEIC) Transistors.

    DTIC Science & Technology

    INTEGRATED CIRCUITS, *MONOLITHIC STRUCTURES(ELECTRONICS), *TRANSISTORS, CHIPS(ELECTRONICS), FABRICATION, EPITAXIAL GROWTH, ULTRAHIGH FREQUENCY, POLYSILICONS, PHOTOLITHOGRAPHY, RADIOFREQUENCY POWER, IMPEDANCE MATCHING .

  6. Consolidation and densification methods for fibrous monolith processing

    SciTech Connect

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2004-05-25

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered in an inert gas or nitrogen gas at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  7. Role of the membrane in the formation of heme degradation products in red blood cells

    PubMed Central

    Nagababu, Enika; Mohanty, Joy G.; Bhamidipaty, Surya; Ostera, Graciela R.; Rifkind, Joseph M.

    2010-01-01

    Aims Red blood cells (RBCs) have an extensive antioxidant system designed to eliminate the formation of reactive oxygen species (ROS). Nevertheless, RBC oxidant stress has been demonstrated by the formation of a fluorescent heme degradation product (ex.321 nm, em 465 nm) both in vitro and in vivo. We investigated the possibility that the observed heme degradation results from ROS generated on the membrane surface that are relatively inaccessible to the cellular antioxidants. Main Methods Membrane and cytosol were separated by centrifugation and the fluorescence intensity and emission maximum was measured. The effect on the maximum emission of adding oxidized and reduced hemoglobin to the fluorescent product formed when hemin is degraded by H2O2 was studied. Key findings 90% of the fluorescent heme degradation products in hemolysates are found on the membrane. Furthermore, these products are not transferred from the cytosol to the membrane and must, therefore, be formed on the membrane. We also showed that the elevated level of heme degradation in HbCC cells that is attributed to increased oxidative stress was found on the membrane. Significance These results suggest that, although ROS generated in the cytosol are neutralized by antioxidant enzymes, H2O2 generated by the membrane bound hemoglobin is not accessible to the cytostolic antioxidants and reacts to generate fluorescent heme degradation products. The formation of H2O2 on the membrane surface can explain the release of ROS from the RBC to other tissues and ROS damage to the membrane that can alter red cell function and lead to the removal of RBCs from circulation by macrophages. PMID:19958781

  8. Alumina composites for oxide/oxide fibrous monoliths

    SciTech Connect

    Cruse, T. A.; Polzin, B. J.; Picciolo, J. J.; Singh, D.; Tsaliagos, R. N.; Goretta, K. C.

    2000-03-01

    Most work on ceramic fibrous monoliths (FMs) has focused on the Si{sub 3}N{sub 4}/BN system. In an effort to develop oxidation-resistant FMs, several oxide systems have recently been examined. Zirconia-toughened alumina and alumina/mullite appear to be good candidates for the cell phase of FMs. These composites offer higher strength and toughness than pure alumina and good high-temperature stability. By combining these oxides, possibly with a weaker high-temperature oxide as the cell-boundary phase, it should be possible to product a strong, resilient FM that exhibits graceful failure. Several material combinations have been examined. Results on FM fabrication and microstructural development are presented.

  9. Heterogeneous Monolithic Integration of Single-Crystal Organic Materials.

    PubMed

    Park, Kyung Sun; Baek, Jangmi; Park, Yoonkyung; Lee, Lynn; Hyon, Jinho; Koo Lee, Yong-Eun; Shrestha, Nabeen K; Kang, Youngjong; Sung, Myung Mo

    2017-02-01

    Manufacturing high-performance organic electronic circuits requires the effective heterogeneous integration of different nanoscale organic materials with uniform morphology and high crystallinity in a desired arrangement. In particular, the development of high-performance organic electronic and optoelectronic devices relies on high-quality single crystals that show optimal intrinsic charge-transport properties and electrical performance. Moreover, the heterogeneous integration of organic materials on a single substrate in a monolithic way is highly demanded for the production of fundamental organic electronic components as well as complex integrated circuits. Many of the various methods that have been designed to pattern multiple heterogeneous organic materials on a substrate and the heterogeneous integration of organic single crystals with their crystal growth are described here. Critical issues that have been encountered in the development of high-performance organic integrated electronics are also addressed.

  10. Method of producing monolithic ceramic cross-flow filter

    DOEpatents

    Larsen, David A.; Bacchi, David P.; Connors, Timothy F.; Collins, III, Edwin L.

    1998-01-01

    Ceramic filter of various configuration have been used to filter particulates from hot gases exhausted from coal-fired systems. Prior ceramic cross-flow filters have been favored over other types, but those previously horn have been assemblies of parts somehow fastened together and consequently subject often to distortion or delamination on exposure hot gas in normal use. The present new monolithic, seamless, cross-flow ceramic filters, being of one-piece construction, are not prone to such failure. Further, these new products are made by novel casting process which involves the key steps of demolding the ceramic filter green body so that none of the fragile inner walls of the filter is cracked or broken.

  11. Crack-free polydimethylsiloxane-bioactive glass-poly(ethylene glycol) hybrid monoliths with controlled biomineralization activity and mechanical property for bone tissue regeneration.

    PubMed

    Chen, Jing; Du, Yuzhang; Que, Wenxiu; Xing, Yonglei; Chen, Xiaofeng; Lei, Bo

    2015-12-01

    Crack-free organic-inorganic hybrid monoliths with controlled biomineralization activity and mechanical property have an important role for highly efficient bone tissue regeneration. Here, biomimetic and crack-free polydimethylsiloxane (PDMS)-modified bioactive glass (BG)-poly(ethylene glycol) (PEG) (PDMS-BG-PEG) hybrids monoliths were prepared by a facile sol-gel technique. Results indicate that under the assist of co-solvents, BG sol and PDMS and PEG could be hybridized at a molecular level, and effects of the PEG molecular weight on the structure, biomineralization activity, and mechanical property of the as-prepared hybrid monoliths were also investigated in detail. It is found that an addition of low molecular weight PEG can significantly prevent the formation of cracks and speed up the gelation of the hybrid monoliths, and the surface microstructure of the hybrid monoliths can be changed from the porous to the smooth as the PEG molecular weight increases. Additionally, the hybrid monoliths with low molecular weight PEG show the high formation of the biological apatite layer, while the hybrids with high molecular weight PEG exhibit negligible biomineralization ability in simulated body fluid (SBF). Furthermore, the PDMS-BG-PEG 600 hybrid monolith has significantly high compressive strength (32 ± 3 MPa) and modulus (153 ± 11 MPa), as well as good cell biocompatibility by supporting osteoblast (MC3T3-E1) attachment and proliferation. These results indicate that the as-prepared PDMS-BG-PEG hybrid monoliths may have promising applications for bone tissue regeneration.

  12. Influence of the nitrogen source on Saccharomyces cerevisiae anaerobic growth and product formation.

    PubMed Central

    Albers, E; Larsson, C; Lidén, G; Niklasson, C; Gustafsson, L

    1996-01-01

    To prevent the loss of raw material in ethanol production by anaerobic yeast cultures, glycerol formation has to be reduced. In theory, this may be done by providing the yeast with amino acids, since the de novo cell synthesis of amino acids from glucose and ammonia gives rise to a surplus of NADH, which has to be reoxidized by the formation of glycerol. An industrial strain of Saccharomyces cerevisiae was cultivated in batch cultures with different nitrogen sources, i.e., ammonium salt, glutamic acid, and a mixture of amino acids, with 20 g of glucose per liter as the carbon and energy source. The effects of the nitrogen source on metabolite formation, growth, and cell composition were measured. The glycerol yields obtained with glutamic acid (0.17 mol/mol of glucose) or with the mixture of amino acids (0.10 mol/mol) as a nitrogen source were clearly lower than those for ammonium-grown cultures (0.21 mol/mol). In addition, the ethanol yield increased for growth on both glutamic acid (by 9%) and the mixture of amino acids (by 14%). Glutamic acid has a large influence on the formation of products; the production of, for example, alpha-ketoglutaric acid, succinic acid, and acetic acid, increased compared with their production with the other nitrogen sources. Cultures grown on amino acids have a higher specific growth rate (0.52 h-1) than cultures of both ammonium-grown (0.45 h-1) and glutamic acid-grown (0.33 h-1) cells. Although the product yields differed, similar compositions of the cells were attained. The NADH produced in the amino acid, RNA, and extracellular metabolite syntheses was calculated together with the corresponding glycerol formation. The lower-range values of the theoretically calculated yields of glycerol were in good agreement with the experimental yields, which may indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential. PMID:8795209

  13. 3D statistical failure analysis of monolithic dental ceramic crowns.

    PubMed

    Nasrin, Sadia; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I

    2016-07-05

    For adhesively retained ceramic crown of various types, it has been clinically observed that the most catastrophic failures initiate from the cement interface as a result of radial crack formation as opposed to Hertzian contact stresses originating on the occlusal surface. In this work, a 3D failure prognosis model is developed for interface initiated failures of monolithic ceramic crowns. The surface flaw distribution parameters determined by biaxial flexural tests on ceramic plates and point-to-point variations of multi-axial stress state at the intaglio surface are obtained by finite element stress analysis. They are combined on the basis of fracture mechanics based statistical failure probability model to predict failure probability of a monolithic crown subjected to single-cycle indentation load. The proposed method is verified by prior 2D axisymmetric model and experimental data. Under conditions where the crowns are completely bonded to the tooth substrate, both high flexural stress and high interfacial shear stress are shown to occur in the wall region where the crown thickness is relatively thin while high interfacial normal tensile stress distribution is observed at the margin region. Significant impact of reduced cement modulus on these stress states is shown. While the analyses are limited to single-cycle load-to-failure tests, high interfacial normal tensile stress or high interfacial shear stress may contribute to degradation of the cement bond between ceramic and dentin. In addition, the crown failure probability is shown to be controlled by high flexural stress concentrations over a small area, and the proposed method might be of some value to detect initial crown design errors.

  14. Formation and modeling of disinfection by-products in drinking water of six cities in China.

    PubMed

    Ye, Bixiong; Wang, Wuyi; Yang, Linsheng; Wei, Jianrong; E, Xueli

    2011-05-01

    Water quality parameters including TOC, UV(254), pH, chlorine dosage, bromide concentration and disinfection by-products were measured in water samples from 41 water treatment plants of six selected cities in China. Chloroform, bromodichloromethane, dibromochloromethane, dichloroacetic acid and trichloroacetic acid were the major disinfection by-products in the drinking water of China. Bromoform and dibromoacetic acid were also detected in many water samples. Higher concentrations of trihalomethanes and haloacetic acids were measured in summer compared to winter. The geographical variations in DBPs showed that TTHM levels were higher in Zhengzhou and Tianjin than other selected cities. And the HAA5 levels were highest in Changsha and Tianjin. The modeling procedure that predicts disinfection by-products formation was studied and developed using artificial neural networks. The performance of the artificial neural networks model was excellent (r > 0.84).

  15. Fermentation strategies for 1,3-propanediol production from glycerol using a genetically engineered Klebsiella pneumoniae strain to eliminate by-product formation.

    PubMed

    Oh, Baek-Rock; Seo, Jeong-Woo; Heo, Sun-Yeon; Hong, Won-Kyung; Luo, Lian Hua; Son, Jun Ho; Park, Don-Hee; Kim, Chul-Ho

    2012-01-01

    We generated a genetically engineered Klebsiella pneumoniae strain (AK-VOT) to eliminate by-product formation during production of 1,3-propanediol (1,3-PD) from glycerol. In the present study, the glycerol-metabolizing properties of the recombinant strain were examined during fermentation in a 5 L bioreactor. As expected, by-product formation was completely absent (except for acetate) when the AK-VOT strain fermented glycerol. However, 1,3-PD productivity was severely reduced owing to a delay in cell growth attributable to a low rate of glycerol consumption. This problem was solved by establishing a two-stage process separating cell growth from 1,3-PD production. In addition, nutrient co-supplementation, especially with starch, significantly increased 1,3-PD production from glycerol during fed-batch fermentation by AK-VOT in the absence of by-product formation.

  16. [Formation of disinfection by-products: temperature effect and kinetic modeling].

    PubMed

    Zhang, Xiao-Lu; Yang, Hong-Wei; Wang, Xiao-Mao; Fu, Jing; Xie, Yue-Feng

    2012-11-01

    Water temperature has significant effects on the disinfection by-product (DBP) formation and concentration in many water utilities and distribution systems. To study the temperature effect on the DBP concentration, the uniform formation condition (UFC) test was referred in testing the formation concentration of DBPs [including (trihalomethanes) THMs and (haloacetic acids) HAAs] at different temperatures during chlorination of the humic acid (HA) solution. A kinetic model was consequently proposed to predict DBP concentration during chlorination. Results show that for the three detected DBPs, including chloroform (CHCl3), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), increasing temperature could considerably enhance both the DBP formation rates and the maximum DBP concentrations, where the maximum concentrations increase exponentially with the water temperature (R2 > 0.90). By using the data-processing software Origin, the detected DBP values were fitted using the proposed first order kinetic model, and the result showed a strong correlation for each DBP at various temperatures (R > 0.94). The apparent reaction rate constant k was also derived for each DBP. In order to quantify the temperature effect on DBP formation, the Arrhenius Equation was employed to calculate the apparent reaction activation energy for each DBP-22.3, 25.5 and 40.8 kJ x mol(-1) for CHCl3, DCAA and TCAA, respectively. By comparing the model predicted and the detected DBP values at 20 and 30 degrees C, the model showed a strong performance in predicting DBP formation concentrations, which indicated the reliability and validity of this proposed kinetic model.

  17. Product formation controlled by substrate dynamics in leukotriene A4 hydrolase.

    PubMed

    Stsiapanava, Alena; Tholander, Fredrik; Kumar, Ramakrishnan B; Qureshi, Abdul Aziz; Niegowski, Damian; Hasan, Mahmudul; Thunnissen, Marjolein; Haeggström, Jesper Z; Rinaldo-Matthis, Agnes

    2014-02-01

    Leukotriene A4 hydrolase/aminopeptidase (LTA4H) (EC 3.3.2.6) is a bifunctional zinc metalloenzyme with both an epoxide hydrolase and an aminopeptidase activity. LTA4H from the African claw toad, Xenopus laevis (xlLTA4H) has been shown to, unlike the human enzyme, convert LTA4 to two enzymatic metabolites, LTB4 and another biologically active product Δ(6)-trans-Δ(8)-cis-LTB4 (5(S),12R-dihydroxy-6,10-trans-8,14-cis-eicosatetraenoic acid). In order to study the molecular aspect of the formation of this product we have characterized the structure and function of xlLTA4H. We solved the structure of xlLTA4H to a resolution of 2.3Å. It is a dimeric structure where each monomer has three domains with the active site in between the domains, similar as to the human structure. An important difference between the human and amphibian enzyme is the phenylalanine to tyrosine exchange at position 375. Our studies show that mutating F375 in xlLTA4H to tyrosine abolishes the formation of the LTB4 isomeric product Δ(6)-trans-Δ(8)-cis-LTB4. In an attempt to understand how one amino acid exchange leads to a new product profile as seen in the xlLTA4H, we performed a conformer analysis of the triene part of the substrate LTA4. Our results show that the Boltzmann distribution of substrate conformers correlates with the observed distribution of products. We suggest that the observed difference in product profile between the human and the xlLTA4H arises from different level of discrimination between substrate LTA4 conformers.

  18. Bioprocess intensification in flow-through monolithic microbioreactors with immobilized bacteria.

    PubMed

    Akay, G; Erhan, E; Keskinler, B

    2005-04-20

    Microporous polymers (with porosity up to 90%) with a well-prescribed internal microstructure were prepared in monolithic form to construct a flow-through microbioreactor in which phenol-degrading bacteria, Pseudomonas syringae, was immobilized. Initially, bacteria was forced seeded within the pores and subsequently allowed to proliferate followed by acclimatization and phenol degradation at various initial substrate concentrations and flow rates. Two types of microporous polymer were used as the monolithic support. These polymers differ with respect to their pore and interconnect sizes, macroscopic surface area for bacterial support, and phase volume. Polymer with a nominal pore size of 100 microm with phase volume of 90% (with highly open pore structure) yielded reduced bacterial proliferation, while the polymer with nominal pore size of 25 microm with phase volume of 85% (with small interconnect size and large pore area for bacterial adhesion) yielded monolayer bacterial proliferation. Bacteria within the 25 microm polymer support remained monolayered, without any apparent production of extracellular matrix during the 30-day continuous experimental period. The microbioreactor performance was characterized in terms of volumetric utilization rate and compared with the published data, including the case where the same bacteria was immobilized on the surface of microporous polymer beads and used in a packed bed during continuous degradation of phenol. It is shown that at similar initial substrate concentration, the volumetric utilization in the microreactor is at least 20-fold more efficient than the packed bed, depending on the flow rate of the substrate solution. The concentration of the bacteria within the pores of the microreactor decreases from 2.25 cells per microm2 on the top surface to about 0.4 cells per microm2 within 3 mm reactor depth. If the bacteria-depleted part of the microreactor is disregarded, the volumetric utilization increases by a factor of 30

  19. Catalytic by-product formation and ligand binding by ribulose bisphosphate carboxylases from different phylogenies.

    PubMed

    Pearce, F Grant

    2006-11-01

    During catalysis, all Rubisco (D-ribulose-1,5-bisphosphate carboxylase/oxygenase) enzymes produce traces of several by-products. Some of these by-products are released slowly from the active site of Rubisco from higher plants, thus progressively inhibiting turnover. Prompted by observations that Form I Rubisco enzymes from cyanobacteria and red algae, and the Form II Rubisco enzyme from bacteria, do not show inhibition over time, the production and binding of catalytic by-products was measured to ascertain the underlying differences. In the present study we show that the Form IB Rubisco from the cyanobacterium Synechococcus PCC6301, the Form ID enzyme from the red alga Galdieria sulfuraria and the low-specificity Form II type from the bacterium Rhodospirillum rubrum all catalyse formation of by-products to varying degrees; however, the by-products are not inhibitory under substrate-saturated conditions. Study of the binding and release of phosphorylated analogues of the substrate or reaction intermediates revealed diverse strategies for avoiding inhibition. Rubisco from Synechococcus and R. rubrum have an increased rate of inhibitor release. G. sulfuraria Rubisco releases inhibitors very slowly, but has an increased binding constant and maintains the enzyme in an activated state. These strategies may provide information about enzyme dynamics, and the degree of enzyme flexibility. Our observations also illustrate the phylogenetic diversity of mechanisms for regulating Rubisco and raise questions about whether an activase-like mechanism should be expected outside the green-algal/higher-plant lineage.

  20. Formation of highly oxygenated low-volatility products from cresol oxidation

    NASA Astrophysics Data System (ADS)

    Schwantes, Rebecca H.; Schilling, Katherine A.; McVay, Renee C.; Lignell, Hanna; Coggon, Matthew M.; Zhang, Xuan; Wennberg, Paul O.; Seinfeld, John H.

    2017-03-01

    Hydroxyl radical (OH) oxidation of toluene produces ring-retaining products: cresol and benzaldehyde, and ring-opening products: bicyclic intermediate compounds and epoxides. Here, first- and later-generation OH oxidation products from cresol and benzaldehyde are identified in laboratory chamber experiments. For benzaldehyde, first-generation ring-retaining products are identified, but later-generation products are not detected. For cresol, low-volatility (saturation mass concentration, C* ˜ 3.5 × 104 - 7.7 × 10-3 µg m-3), first- and later-generation ring-retaining products are identified. Subsequent OH addition to the aromatic ring of o-cresol leads to compounds such as hydroxy, dihydroxy, and trihydroxy methyl benzoquinones and dihydroxy, trihydroxy, tetrahydroxy, and pentahydroxy toluenes. These products are detected in the gas phase by chemical ionization mass spectrometry (CIMS) and in the particle phase using offline direct analysis in real-time mass spectrometry (DART-MS). Our data suggest that the yield of trihydroxy toluene from dihydroxy toluene is substantial. While an exact yield cannot be reported as authentic standards are unavailable, we find that a yield for trihydroxy toluene from dihydroxy toluene of ˜ 0.7 (equal to the reported yield of dihydroxy toluene from o-cresol; Olariu et al., 2002) is consistent with experimental results for o-cresol oxidation under low-NO conditions. These results suggest that even though the cresol pathway accounts for only ˜ 20 % of the oxidation products of toluene, it is the source of a significant fraction (˜ 20-40 %) of toluene secondary organic aerosol (SOA) due to the formation of low-volatility products.

  1. Klebsiella pneumoniae yfiRNB operon affects biofilm formation, polysaccharide production and drug susceptibility.

    PubMed

    Huertas, Mónica G; Zárate, Lina; Acosta, Iván C; Posada, Leonardo; Cruz, Diana P; Lozano, Marcela; Zambrano, María M

    2014-12-01

    Klebsiella pneumoniae is an opportunistic pathogen important in hospital-acquired infections, which are complicated by the rise of drug-resistant strains and the capacity of cells to adhere to surfaces and form biofilms. In this work, we carried out an analysis of the genes in the K. pneumoniae yfiRNB operon, previously implicated in biofilm formation. The results indicated that in addition to the previously reported effect on type 3 fimbriae expression, this operon also affected biofilm formation due to changes in cellulose as part of the extracellular matrix. Deletion of yfiR resulted in enhanced biofilm formation and an altered colony phenotype indicative of cellulose overproduction when grown on solid indicator media. Extraction of polysaccharides and treatment with cellulase were consistent with the presence of cellulose in biofilms. The enhanced cellulose production did not, however, correlate with virulence as assessed using a Caenorhabditis elegans assay. In addition, cells bearing mutations in genes of the yfiRNB operon varied with respect to the WT control in terms of susceptibility to the antibiotics amikacin, ciprofloxacin, imipenem and meropenem. These results indicated that the yfiRNB operon is implicated in the production of exopolysaccharides that alter cell surface characteristics and the capacity to form biofilms--a phenotype that does not necessarily correlate with properties related with survival, such as resistance to antibiotics.

  2. Growth and final product formation by Bifidobacterium infantis in aerated fermentations.

    PubMed

    González, R; Blancas, A; Santillana, R; Azaola, A; Wacher, C

    2004-10-01

    Fermentation conditions were developed to allow Bifidobacterium infantis to grow in the presence of air. Batch fermentations in TPYG medium, starting from anoxic conditions followed by the application of low airflow rates [0.02-0.1 air volume, per liquid media volume, per minute (vvm)], were analyzed for growth, oxygen uptake, and product formation by the bacterium. Under all aerated fermentations, B. infantis showed high aerotolerance, with a maximum oxygen-specific consumption rate of 0.34 mmol oxygen per gram dry cell weight per hour in the presence of 0.06 vvm. Similar growth yields were obtained under oxic and anoxic conditions (0.11-0.13 and 0.11 g dry cell weight per mmol glucose, respectively). Oxygen also influenced metabolite formation since lactate production and its molar relation to acetate increased and formate decreased with aeration rate. Under anoxic conditions, a maximum concentration of 8.1 mM lactate and an acetate/lactate ratio of 3.5:1 were obtained, while under oxic conditions the lactate concentration increased more than two-fold and the acetate/lactate molar ratio decreased to 1.5:1. The possibility of balancing acetate/lactate molar ratios for organoleptic purposes as well as for obtaining good growth under microaerated conditions was demonstrated.

  3. Cinnamon bark oil and its components inhibit biofilm formation and toxin production.

    PubMed

    Kim, Yong-Guy; Lee, Jin-Hyung; Kim, Soon-Il; Baek, Kwang-Hyun; Lee, Jintae

    2015-02-16

    The long-term usage of antibiotics has resulted in the evolution of multidrug resistant bacteria, and pathogenic biofilms contribute to reduced susceptibility to antibiotics. In this study, 83 essential oils were initially screened for biofilm inhibition against Pseudomonas aeruginosa. Cinnamon bark oil and its main constituent cinnamaldehyde at 0.05% (v/v) markedly inhibited P. aeruginosa biofilm formation. Furthermore, cinnamon bark oil and eugenol decreased the production of pyocyanin and 2-heptyl-3-hydroxy-4(1H)-quinolone, the swarming motility, and the hemolytic activity of P. aeruginosa. Also, cinnamon bark oil, cinnamaldehyde, and eugenol at 0.01% (v/v) significantly decreased biofilm formation of enterohemorrhagic Escherichia coli O157:H7 (EHEC). Transcriptional analysis showed that cinnamon bark oil down-regulated curli genes and Shiga-like toxin gene stx2 in EHEC. In addition, biodegradable poly(lactic-co-glycolic acid) film incorporating biofilm inhibitors was fabricated and shown to provide efficient biofilm control on solid surfaces. This is the first report that cinnamon bark oil and its components, cinnamaldehyde and eugenol, reduce the production of pyocyanin and PQS, the swarming motility, and the hemolytic activity of P. aeruginosa, and inhibit EHEC biofilm formation.

  4. Leaching of mercury-containing cement monoliths aged for one year.

    PubMed

    Svensson, Margareta; Allard, Bert

    2008-01-01

    A directive from the Swedish Government states that waste containing more than 1% of mercury shall be permanently deposited. The stabilization of mercury by conversion to a sparingly soluble compound like the sulphide is crucial to ensure long-term immobilization in a permanent storage. Immobilization by the solidification/stabilization (S/S) method and possible formation of HgS from mercury oxide or elemental mercury by reaction with a sulphur source (S or FeS) is investigated by a modified version of the NEN 7345 Dutch tank-leaching test. The diffusion of mercury during 11 months from 1-year-old mercury containing monoliths of Portland and slag cement is demonstrated. In a geologic repository under conditions representative of deep granitic bedrock (bicarbonate buffered to pH 8.6), a favourable monolith combination is slag cement with addition of the iron sulphide troilite. The apparent diffusion coefficient of mercury is estimated.

  5. Inhibition of advanced glycation end-product formation on eye lens protein by rutin.

    PubMed

    Muthenna, P; Akileshwari, C; Saraswat, Megha; Bhanuprakash Reddy, G

    2012-04-01

    Formation of advanced glycation end products (AGE) plays a key role in the several pathophysiologies associated with ageing and diabetes, such as arthritis, atherosclerosis, chronic renal insufficiency, Alzheimer's disease, nephropathy, neuropathy and cataract. This raises the possibility of inhibition of AGE formation as one of the approaches to prevent or arrest the progression of diabetic complications. Previously, we have reported that some common dietary sources such as fruits, vegetables, herbs and spices have the potential to inhibit AGE formation. Flavonoids are abundantly found in fruits, vegetables, herbs and spices, and rutin is one of the commonly found dietary flavonols. In the present study, we have demonstrated the antiglycating potential and mechanism of action of rutin using goat eye lens proteins as model proteins. Under in vitro conditions, rutin inhibited glycation as assessed by SDS-PAGE, AGE-fluorescence, boronate affinity chromatography and immunodetection of specific AGE. Further, we provided insight into the mechanism of inhibition of protein glycation that rutin not only scavenges free-radicals directly but also chelates the metal ions by forming complexes with them and thereby partly inhibiting post-Amadori formation. These findings indicate the potential of rutin to prevent and/or inhibit protein glycation and the prospects for controlling AGE-mediated diabetic pathological conditions in vivo.

  6. Antarctic Bottom Water production by intense sea-ice formation in the Cape Darnley polynya

    NASA Astrophysics Data System (ADS)

    Ohshima, Kay I.; Fukamachi, Yasushi; Williams, Guy D.; Nihashi, Sohey; Roquet, Fabien; Kitade, Yujiro; Tamura, Takeshi; Hirano, Daisuke; Herraiz-Borreguero, Laura; Field, Iain; Hindell, Mark; Aoki, Shigeru; Wakatsuchi, Masaaki

    2013-03-01

    The formation of Antarctic Bottom Water--the cold, dense water that occupies the abyssal layer of the global ocean--is a key process in global ocean circulation. This water mass is formed as dense shelf water sinks to depth. Three regions around Antarctica where this process takes place have been previously documented. The presence of another source has been identified in hydrographic and tracer data, although the site of formation is not well constrained. Here we document the formation of dense shelf water in the Cape Darnley polynya (65°-69°E) and its subsequent transformation into bottom water using data from moorings and instrumented elephant seals (Mirounga leonina). Unlike the previously identified sources of Antarctic Bottom Water, which require the presence of an ice shelf or a large storage volume, bottom water production at the Cape Darnley polynya is driven primarily by the flux of salt released by sea-ice formation. We estimate that about 0.3-0.7×106m3s-1 of dense shelf water produced by the Cape Darnley polynya is transformed into Antarctic Bottom Water. The transformation of this water mass, which we term Cape Darnley Bottom Water, accounts for 6-13% of the circumpolar total.

  7. Methane production from formate, acetate and H2/CO2; focusing on kinetics and microbial characterization.

    PubMed

    Pan, Xiaofang; Angelidaki, Irini; Alvarado-Morales, Merlin; Liu, Houguang; Liu, Yuhong; Huang, Xu; Zhu, Gefu

    2016-10-01

    For evaluating the methanogenesis from typical methanogenic precursors (formate, acetate and H2/CO2), CH4 production kinetics were investigated at 37±1°C in batch anaerobic digestion tests and stimulated by modified Gompertz model. The results showed that maximum methanation rate from formate, acetate and H2/CO2 were 19.58±0.49, 42.65±1.17 and 314.64±3.58NmL/gVS/d in digested manure system and 6.53±0.31, 132.04±3.96 and 640.16±19.92NmL/gVS/d in sewage sludge system during second generation incubation. Meanwhile the model could not fit well in granular sludge system, while the rate of formate methanation was faster than from H2/CO2 and acetate. Considering both the kinetic results and microbial assay we could conclude that H2/CO2 methanation was the fastest methanogenic step in digested manure and sewage sludge system with Methanomicrobiales as dominant methanogens, while granular sludge with Methanobacteriales as dominant methanogens contributed to the fastest formate methanation.

  8. Westerlund 1: monolithic formation of a starburst cluster

    NASA Astrophysics Data System (ADS)

    Negueruela, Ignacio; Clark, J. Simon; Ritchie, Ben W.; Goodwin, Simon P.

    2017-03-01

    Westerlund 1 is in all likelihood the most massive young cluster in the Milky Way, with a mass on the order of 105 M ⊙. To determine its bulk properties we have made multi-epoch radial velocity measurements for a substantial fraction of its OB stars and evolved supergiants and obtained multi-object spectroscopy of candidate cluster members in its locale. The results of these two studies show that Westerlund 1 is apparently subvirial and appears completely isolated, with hardly any massive star in its vicinity that could be associated with it in terms of distance modulus or radial velocity. The cluster halo does not extend much further than five parsec away from the centre. All these properties are very unusual among starburst clusters in the Local Universe, which tend to form in the context of large star-forming regions.

  9. Sliding Motility, Biofilm Formation, and Glycopeptidolipid Production in Mycobacterium colombiense Strains

    PubMed Central

    Maya-Hoyos, Milena; Leguizamón, John; Mariño-Ramírez, Leonardo; Soto, Carlos Y.

    2015-01-01

    Mycobacterium colombiense is a novel member of the Mycobacterium avium complex, which produces respiratory and disseminated infections in immunosuppressed patients. Currently, the morphological and genetic bases underlying the phenotypic features of M. colombiense strains remain unknown. In the present study, we demonstrated that M. colombiense strains displaying smooth morphology show increased biofilm formation on hydrophobic surfaces and sliding on motility plates. Thin-layer chromatography experiments showed that M. colombiense strains displaying smooth colonies produce large amounts of glycolipids with a chromatographic behaviour similar to that of the glycopeptidolipids (GPLs) of M. avium. Conversely, we observed a natural rough variant of M. colombiense (57B strain) lacking pigmentation and exhibiting impaired sliding, biofilm formation, and GPL production. Bioinformatics analyses revealed a gene cluster that is likely involved in GPL biosynthesis in M. colombiense CECT 3035. RT-qPCR experiments showed that motile culture conditions activate the transcription of genes possibly involved in key enzymatic activities of GPL biosynthesis. PMID:26180799

  10. Quercetin inhibits advanced glycation end product formation by trapping methylglyoxal and glyoxal.

    PubMed

    Li, Xiaoming; Zheng, Tiesong; Sang, Shengmin; Lv, Lishuang

    2014-12-17

    Methylglyoxal (MGO) and glyoxal (GO) not only are endogenous metabolites but also exist in exogenous resources, such as foods, beverages, urban atmosphere, and cigarette smoke. They have been identified as reactive dicarbonyl precursors of advanced glycation end products (AGEs), which have been associated with diabetes-related long-term complications. In this study, quercetin, a natural flavonol found in fruits, vegetables, leaves, and grains, could effectively inhibit the formation of AGEs in a dose-dependent manner via trapping reactive dicarbonyl compounds. More than 50.5% of GO and 80.1% of MGO were trapped at the same time by quercetin within 1 h under physiological conditions. Quercetin and MGO (or GO) were combined at different ratios, and the products generated from this reaction were analyzed with LC-MS. Both mono-MGO and di-MGO adducts of quercetin were detected in this assay using LC-MS, but only tiny amounts of mono-GO adducts of quercetin were found. Additionally, di-MGO adducts were observed as the dominant product with prolonged incubation time. In the bovine serum albumin (BSA)-MGO/GO system, quercetin traps MGO and GO directly and then significantly inhibits the formation of AGEs.

  11. The organic precursors affecting the formation of disinfection by-products with chlorine dioxide.

    PubMed

    Chang, C Y; Hsieh, Y H; Lin, Y M; Hu, P Y; Liu, C C; Wang, K H

    2001-08-01

    The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics.

  12. Regulation of Product Formation in Bacteroides xylanolyticus X5-1 by Interspecies Electron Transfer

    PubMed Central

    Biesterveld, Steven; Zehnder, Alexander J. B.; Stams, Alfons J. M.

    1994-01-01

    Bacteroides xylanolyticus X5-1 was grown in pure culture and in mixed culture with Methanospirillum hungatei JF-1 under xylose limitation in the chemostat. In the pure culture, ethanol, acetate, CO2, and hydrogen were the products. In the mixed culture, acetate, CO2, and presumably hydrogen were the only products formed by B. xylanolyticus X5-1. The biomass yield of B. xylanolyticus X5-1 increased because of cocultivation. In cell extracts of the pure culture, both NAD- and NADP-dependent acetaldehyde dehydrogenase and ethanol dehydrogenase activities were found. In cell extracts of the mixed culture, activities of these enzymes were not detected. Inhibition of methanogenesis in the mixed culture by the addition of bromoethanosulfonic acid (BES) resulted in an accumulation of H2, ethanol, and formate. Immediately after the addition of BES, NAD-dependent acetaldehyde dehydrogenase and ethanol dehydrogenase activities were detected. After a short lag phase, a NADP-dependent ethanol dehydrogenase was also detectable. The induction of acetaldehyde dehydrogenase and ethanol dehydrogenase was inhibited by chloramphenicol, suggesting de novo synthesis of these enzymes. These results are consistent with a model in which the shift in product formation caused by interspecies electron transfer is regulated at the level of enzyme synthesis. PMID:16349240

  13. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-02-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  14. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-06-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  15. Singlet oxygen oxidation of isolated and cellular DNA: product formation and mechanistic insights.

    PubMed

    Cadet, Jean; Ravanat, Jean-Luc; Martinez, Glaucia R; Medeiros, Marisa H G; Di Mascio, Paolo

    2006-01-01

    This survey focuses on recent aspects of the singlet oxygen oxidation of the guanine moiety of nucleosides, oligonucleotides, isolated and cellular DNA that has been shown to be the exclusive DNA target for this biologically relevant photogenerated oxidant. A large body of mechanistic data is now available from studies performed on nucleosides in both aprotic solvents and aqueous solutions. A common process to both reaction conditions is the formation of 8-oxo-7,8-dihydroguanine by reduction of 8-hydroperoxyguanine that arises from the rearrangement of initially formed endoperoxide across the 4,8-bond of the purine moiety. However, in organic solvent the hydroperoxide is converted as a major degradation pathway into a dioxirane that subsequently decomposes into a complex pattern of oxidation products. A different reaction that involved the formation of a highly reactive quinonoid intermediate consecutively to the loss of a water molecule from the 8-hydroperoxide has been shown to occur in aqueous solution. Subsequent addition of a water molecule at C5 leads to the generation of a spiroiminodihy-dantoin compound via a rearrangement that involves an acyl shift. However, in both isolated and cellular DNA the latter decomposition pathway is at the best a minor process, because only 8-oxo-7,8-dihydroguanine has been found to be generated. It is interesting to point out that singlet oxygen has been shown to contribute predominantly to the formation of 8-oxo-7,8-dihydroguanine in the DNA of bacterial and human cells upon exposure to UVA radiation. It may be added that the formation of secondary singlet-oxygen oxidation products of 8-oxo-7,8-dihydroguanine, including spiroiminodihydantoin and oxaluric acid that were characterized in nucleosides and oligonucleotide, respectively, have not yet been found in cellular DNA.

  16. A kinetic model for product formation of microbial and mammalian cells

    SciTech Connect

    Zeng, A.P.

    1995-05-20

    Growth of microbial and mammalian cells can be classified into substrate-limited and substrate-sufficient growth according to the relative availability of the substrate (carbon and energy source) and other nutrients. It has been observed for a number of microbial and mammalian cells that the consumption rate of substrate and energy (ATP) is generally higher under substrate-sufficient conditions than under substrate limitation. Accordingly, the product formation under substrate excess often exhibits different patterns from those under substrate limitation. In this study, the Luedeking-Piret kinetic model is extended to include a term describing the effect of residual substrate concentration. The applicability of the extended model is demonstrated with three microbial cultures for the production of primary metabolites and three hybridoma cell cultures for the production of ammonia and lactic acid over a wide range of substrate concentration. Anaerobic fermentation of glycerol by Klebsiella pneumoniae is a multiproduct fermentation process. At a neutral pH value, acetic acid, ethanol, and 1,3-propanediol are the main fermentation products. Formation of acetic acid and/or ethanol is necessary for the generation by K. pneumoniae. The aerobic growth of bacillus strain TS1 on methanol has been studied in methanol-limited and methanol-sufficient hemostat cultures. Under methanol-limited conditions there is no extracellular product formed. However, under methanol-sufficient conditions, particularly with nitrogen limitation, metabolites such as acetic acid and 2-oxoglutaric acid are excreted into the culture medium above a certain level of residual methanol concentration.

  17. Experimental and theoretical study of the influence of water on hydrolyzed product formation during the feruloylation of vegetable oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feruloylated vegetable oil is a valuable green bioproduct that has several cosmeceutical applications associated with its inherent anti-oxidant and UV-absorption properties. Hydrolyzed vegetable oil by-products can influence product quality and consistency. The formation of by-products by residual w...

  18. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, Nguyen Q.; Horne, Craig R.

    1994-01-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array.

  19. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, N.Q.; Horne, C.R.

    1994-03-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array. 10 figures.

  20. Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

  1. Creating deep soil core monoliths: Beyond the solum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil monoliths serve as useful teaching aids in the study of the Earth’s critical zone where rock, soil, water, air, and organisms interact. Typical monolith preparation has so far been confined to the 1 to 2-m depth of the solum. Critical ecosystem services provided by soils include materials from ...

  2. Monolithic LTCC seal frame and lid

    SciTech Connect

    Krueger, Daniel S.; Peterson, Kenneth A.; Stockdale, Dave; Duncan, James Brent; Riggs, Bristen

    2016-06-21

    A method for forming a monolithic seal frame and lid for use with a substrate and electronic circuitry comprises the steps of forming a mandrel from a ceramic and glass based material, forming a seal frame and lid block from a ceramic and glass based material, creating a seal frame and lid by forming a compartment and a plurality of sidewalls in the seal frame and lid block, placing the seal frame and lid on the mandrel such that the mandrel fits within the compartment, and cofiring the seal frame and lid block.

  3. Ozonation of piperidine, piperazine and morpholine: Kinetics, stoichiometry, product formation and mechanistic considerations.

    PubMed

    Tekle-Röttering, Agnes; Jewell, Kevin S; Reisz, Erika; Lutze, Holger V; Ternes, Thomas A; Schmidt, Winfried; Schmidt, Torsten C

    2016-01-01

    Piperidine, piperazine and morpholine as archetypes for secondary heterocyclic amines, a structural unit that is often present in pharmaceuticals (e.g., ritalin, cetirizine, timolol, ciprofloxacin) were investigated in their reaction with ozone. In principle the investigated compounds can be degraded with ozone in a reasonable time, based on their high reaction rate constants with respect to ozone (1.9 × 10(4)-2.4 × 10(5) M(-1) s(-1)). However, transformation is insufficient (13-16%), most likely due to a chain reaction, which decomposes ozone. This conclusion is based on OH scavenging experiments, leading to increased compound transformation (18-27%). The investigated target compounds are similar in their kinetic and stoichiometric characteristics. However, the mechanistic considerations based on product formation indicate various reaction pathways. Piperidine reacts with ozone via a nonradical addition reaction to N-hydroxypiperidine (yield: 92% with and 94% without scavenging, with respect to compound transformation). However, piperazine degradation with ozone does not lead to N-hydroxypiperazine. In the morpholine/ozone reaction, N-hydroxymorpholine was identified. Additional oxidation pathways in all cases involved the formation of OH with high yields. One important pathway of piperazine and morpholine by ozonation could be the formation of C-centered radicals after ozone or OH radical attack. Subsequently, O2 addition forms unstable peroxyl radicals, which in one pathway loose superoxide radicals by generating a carbon-centered cation. Subsequent hydrolysis of the carbon-centered cation leads to formaldehyde, whereby ozonation of the N-hydroxy products can proceed in the same way and in addition give rise to hydroxylamine. A second pathway of the short-lived peroxyl radicals could be a dimerization to form short-lived tetraoxides, which cleave by forming hydrogen peroxide. All three products have been found.

  4. Processing Impact on Monoclonal Antibody Drug Products: Protein Subvisible Particulate Formation Induced by Grinding Stress.

    PubMed

    Gikanga, Benson; Roshan-Eisner, Devon; Ovadia, Robert; Day, Eric S; Stauch, Oliver Boris; Maa, Yuh-Fun

    2016-10-27

    Subvisible particle formation in monoclonal antibody (mAb) drug product resulting from mixing and filling operations represents a significant processing risk that can lead to filter fouling and thereby lead to process delays or failures. Several previous studies from our lab and others demonstrated the formation of subvisible particulates in mAb formulations resulting from mixing operations using some bottom-mounted mixers or stirrer bars. It was hypothesized that the stress (e.g. shear/cavitation) derived from tight clearance and/or close contact between the impeller and shaft was responsible for SvP generation. These studies, however, could not distinguish between the two surfaces without contact (tight clearance) or between two contacting surfaces (close contact). In the present study we expand on those findings and utilize small scale mixing models that are able to, for the first time, distinguish between tight clearances and tight contact. In this study we evaluated different mixer types including a top-mounted mixer, several impeller-based bottom-mounted mixers and a rotary piston pump. The impact of tight clearance/close contact on subvisible particle formation in at-scale mixing platforms was demonstrated in the gap between the impeller and drive unit as well as between the piston and the housing of the pump. Furthermore, small-scale mixing models based on different designs of magnetic stir bars which mimic the tight clearance/close contact of the manufacturing-scale mixers also induced subvisible particles in mAb formulations. Additional small-scale models which feature tight clearance but no close contact (grinding) suggested that it is the repeated grinding/contacting of the moving parts and not the presence of tight clearance in the processing equipment that is the root cause of SvP formation. When multiple mAbs, Fabs (fragment antigen binding) or non-antibody related proteins were mixed in the small-scale mixing model, for molecules investigated, it

  5. Gas, Water, and Oil Production from the Wasatch Formation, Greater Natural Buttes Field, Uinta Basin, Utah

    USGS Publications Warehouse

    Nelson, Philip H.; Hoffman, Eric L.

    2009-01-01

    Gas, oil, and water production data were compiled from 38 wells with production commencing during the 1980s from the Wasatch Formation in the Greater Natural Buttes field, Uinta Basin, Utah. This study is one of a series of reports examining fluid production from tight gas reservoirs, which are characterized by low permeability, low porosity, and the presence of clay minerals in pore space. The general ranges of production rates after 2 years are 100-1,000 mscf/day for gas, 0.35-3.4 barrel per day for oil, and less than 1 barrel per day for water. The water:gas ratio ranges from 0.1 to10 barrel per million standard cubic feet, indicating that free water is produced along with water dissolved in gas in the reservoir. The oil:gas ratios are typical of a wet gas system. Neither gas nor water rates show dependence upon the number of perforations, although for low gas-flow rates there is some dependence upon the number of sandstone intervals that were perforated. Over a 5-year time span, gas and water may either increase or decrease in a given well, but the changes in production rate do not exhibit any dependence upon well proximity or well location.

  6. High density monolithic packaging technology for digital/microwave avionics

    NASA Astrophysics Data System (ADS)

    Fertig, Timothy; Walter, Theresa; Gaver, Eric; Leahy, Kevin

    1994-10-01

    There has been a need for generic technologies and common approaches in design, development, and manufacturing of military and commercial products. This need is more pronounced and pressing today than ever before. With the objective to dramatically enhance avionics reliability, maintainability and availability (RM&A), an integrated, generic technology for packaging, cooling, and interconnection of high density and high performance circuits was developed. It is named High Density Monolithic Packaging (HDMP). Under the sponsorship of Wright Laboratory, a two-part complementary program (1990-1994), named Advanced Radio-Frequency Packaging/ARFP was contracted to Westinghouse. Under the ARFP program, the HDMP technology is being applied and its promising capability is being assessed for its ability to reduce the low power RF avionics life-cycle cost. Being better than half way through the program, the results and projections have been extremely promising. The technology assessment is approximately 50 percent complete and initial results have been extremely successful. Although the focus of the development effort has been on RF subsystems, the basic elements of HDMP technology have applications beyond RF/microwave subsystems. As digital processing speeds increase, RF/microwave design techniques must be applied to maintain high speed digital signal integrity. The basic elements of the HDMP technology are: low temperature co-fired ceramic (LTCC), solderless interconnects, multichip modules (MCM's), and composite heatsink materials. The key technology element, in this avionics availability enabling technology, is LTCC. LTCC material technology is a monolithic multilayered ceramic and conductor/metallization structure used as a substrate to support dense co-habitation of high density electronic circuits, their interconnections, and the electromechanical integrity of the integrated constituents.

  7. Formation of disinfection by-products: effect of temperature and kinetic modeling.

    PubMed

    Zhang, Xiao-lu; Yang, Hong-wei; Wang, Xiao-mao; Fu, Jing; Xie, Yuefeng F

    2013-01-01

    The temperature of drinking water fluctuates naturally in water distribution systems as well as often deliberately heated for household or public uses. In this study, the temperature effect on the formation of disinfection by-products (DBPs) was investigated by monitoring the temporal variations of twenty-one DBPs during the chlorination of a humic precursors-containing water at different temperatures. It was found that chloroform, DCAA, TCAA, DCAN and CH were detected at the considerable level of tens of μg L(-1). The three regulated DBPs (chloroform, DCAA and TCAA) were found increasing with both contact time and water temperature, while the five typical emerging DBPs (DCAN, CH, TCNM 1,1-DCPN and 1,1,1-TCPN) revealed the significant auto-decomposition in addition to the initial growth in the first few hours. Increasing water temperature could enhance the formation rates of all the eight detected DBPs and the decomposition rates of the five emerging DBPs. Further, a kinetic model was developed for the simulation of DBP formation. The validity and universality of the model were verified by its excellent correlation with the detected values of each DBP species at various temperatures. The formation rates of 1,1-DCPN and 1,1,1-TCPN, and the decomposition rate of 1,1,1-TCPN were faster as compared to the other DBPs. And the formation reaction activation energies of CH, DCAN and 1,1-DCPN were relatively large, indicating that their occurrence levels in the finished water were more susceptible to temperature variations.

  8. Formation of calcium in the products of iron oxide-aluminum thermite combustion in air

    NASA Astrophysics Data System (ADS)

    Gromov, A. A.; Gromov, A. M.; Popenko, E. M.; Sergienko, A. V.; Sabinskaya, O. G.; Raab, B.; Teipel, U.

    2016-10-01

    The composition of condensed products resulting from the combustion of thermite mixtures (Al + Fe2O3) in air is studied by precise methods. It is shown that during combustion, calcium is formed and stabilized in amounts of maximal 0.55 wt %, while is missing from reactants of 99.7 wt % purity. To explain this, it is hypothesized that a low-energy nuclear reaction takes place alongside the reactions of aluminum oxidation and nitridation, resulting in the formation of calcium (Kervran-Bolotov reaction).

  9. The formation of disinfection by-products in water treated with chlorine dioxide.

    PubMed

    Chang, C Y; Hsieh, Y H; Hsu, S S; Hu, P Y; Wang, K H

    2000-12-01

    In this study, chlorine dioxide (ClO(2)) was used as an alternative disinfection agent with humic acid as the organic precursor in a natural aquatic environment. The major topics in this investigation consisted of the disinfection efficiency of ClO(2), the formation of disinfection by-products (DBPs), and the operating conditions. The results indicated that the pH value (pH 5-9) did not affect the efficiency of disinfection while the concentration of organic precursors did. The primary DBPs formed were trihalomethanes (THMs) and haloacetic acids (HAAs). The distribution of the individual species was a function of the bromide content. The higher the ClO(2) dosage, the lower the amount of DBPs produced. The amount of DBPs increased with reaction time, with chlorite ions as the primary inorganic by-product.

  10. Isomer-specific product formation in the proton transfer reaction of HOCO+ with CO

    NASA Astrophysics Data System (ADS)

    Carrascosa, Eduardo; Stei, Martin; Kainz, Martin A.; Wester, Roland

    2015-12-01

    The proton transfer reaction HOCO++CO → HCO+/HOC+ has been studied using crossed-beam velocity map imaging. Angular and energy differential cross sections were obtained for collision energies from 0.3 to 2.3 eV. Scattering in forward direction together with a prominent scattering angle-dependent internal excitation is found at all collision energies. The exothermic HCO+ product appears to be very dominant even at energies above the energy threshold for the formation of metastable HOC+ ion. To determine the HOC+ contribution for different angular ranges, a model has been developed. We obtain an upper limit for the HOC+ product isomer fraction of <2%. In theoretical calculations, we find the CO2-catalysed isomerisation channel to be energetically accessible. However, it may not have a strong impact on the isomer ratio. Chemical dynamics simulations are needed to shed more light on this question.

  11. Inhibitory effect of leonurine on the formation of advanced glycation end products.

    PubMed

    Huang, Lianqi; Yang, Xin; Peng, Anlin; Wang, Hui; Lei, Xiang; Zheng, Ling; Huang, Kun

    2015-02-01

    Long-term hyperglycemia is a typical symptom of diabetes mellitus (DM) which can cause a high level of protein glycation and lead to the formation of advanced glycation end products (AGEs). The accumulation of AGEs in turn deteriorates DM and its complications. Insulin, the only hormone that directly decreases blood sugar in vivo, is vulnerable to glycation which causes the loss of its biological activity. In this study, we used a porcine insulin (PI)-methylglyoxal (MGO) model to investigate the inhibitory effect of leonurine (LN), a natural alkaloid extracted from Herba leonuri, on AGE formation. Assays including AGE-specific fluorescence, and fructosamine level and carbonyl group content determination showed that LN can dose-dependently suppress PI glycation. A significantly decreased cross-linking level on the glycated PI was also proven by SDS-PAGE electrophoresis. A further liquid chromatography-mass spectrometry study suggested that LN may inhibit PI glycation through trapping MGO and keeping it from reacting with PI. Our results thus indicate that LN is a promising anti-glycation agent for the prevention of diabetes and its complications via inhibiting AGE formation.

  12. Studying Pellet Formation of a Filamentous Fungus Rhizopus oryzae to Enhance Organic Acid Production

    NASA Astrophysics Data System (ADS)

    Liao, Wei; Liu, Yan; Chen, Shulin

    Using pelletized fungal biomass can effectively improve the fermentation performance for most of fugal strains. This article studied the effects of inoculum and medium compositions such as potato dextrose broth (PDB) as carbon source, soybean peptone, calcium carbonate, and metal ions on pellet formation of Rhizopus oryzae. It has been found that metal ions had significantly negative effects on pellet formation whereas soybean peptone had positive effects. In addition PDB and calcium carbonate were beneficial to R. oryzae for growing small smooth pellets during the culture. The study also demonstrated that an inoculum size of less than 1.5×109 spores/L had no significant influence on pellet formation. Thus, a new approach to form pellets has been developed using only PDB, soybean peptone, and calcium carbonate. Meanwhile, palletized fungal fermentation significantly enhanced organic acid production. Lactic acid concentration reached 65.0 g/L in 30 h using pelletized R. oryzae NRRL 395, and fumeric acid concentration reached 31.0 g/L in 96 h using pelletized R. oryzae ATCC 20344.

  13. [Formation Mechanism of the Disinfection By-product 1, 1-Dichloroacetone in Drinking Water].

    PubMed

    Ding, Chun-sheng; Meng, Zhuang; Xu, Yang-yang; Miao, Jia

    2015-05-01

    A novel method using methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of the disinfection by-producs 1,1-dichloroacetone (DCAce) by gas chromatography mass spectrometry (GC-MS) was described. The formation process of DCAce and its influencing factors were discussed with L-leucine as the precursor during the chloramination process. The results indicated that the DCAce production increased with the increase of chloramine dosage when the chloramine addition was in the range of 5-30 mg · L(-1). The DCAce amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the DCAce amount reduced with the increase of pH value. Temperature was another important factor that affected the DCAce formation from methylamine especially in the range of 15-35°C , and the higher the temperature, the more the DCAce produced. The formation process of DCAce from L-leucine by chloramine consisted of a series of complicated reactions, including substitution, oxidation, bond breaking, amino diazotization, reduction and so on, and eventually DCAce was formed.

  14. Multiple linear regression modeling of disinfection by-products formation in Istanbul drinking water reservoirs.

    PubMed

    Uyak, Vedat; Ozdemir, Kadir; Toroz, Ismail

    2007-06-01

    Oxidation of raw water with chlorine results in formation of trihalomethanes (THM) and haloacetic acids (HAA). Factors affecting their concentrations have been found to be organic matter type and concentration, pH, temperature, chlorine dose, contact time and bromide concentration, but the mechanisms of their formation are still under investigation. Within this scope, chlorination experiments have been conducted with water reservoirs from Terkos, Buyukcekmece and Omerli lakes, Istanbul, with different water quality regarding bromide concentration and organic matter content. The factors studied were pH, contact time, chlorine dose, and specific ultraviolet absorbance (SUVA). The determination of disinfection by-products (DBP) was carried out by gas chromatography techniques. Statistical analysis of the results was focused on the development of multiple regression models for predicting the concentrations of total THM and total HAA based on the use of pH, contact time, chlorine dose, and SUVA. The developed models provided satisfactory estimations of the concentrations of the DBP and the model regression coefficients of THM and HAA are 0.88 and 0.61, respectively. Further, the Durbin-Watson values confirm the reliability of the two models. The results indicate that under these experimental conditions which indicate the variations of pH, chlorine dosages, contact time, and SUVA values, the formation of THM and HAA in water can be described by the multiple linear regression technique.

  15. Catastrophic failure of a monolithic zirconia prosthesis.

    PubMed

    Chang, Jae-Seung; Ji, Woon; Choi, Chang-Hoon; Kim, Sunjai

    2015-02-01

    Recently, monolithic zirconia restorations have received attention as an alternative to zirconia veneered with feldspathic porcelain to eliminate chipping failures of veneer ceramics. In this clinical report, a patient with mandibular edentulism received 4 dental implants in the interforaminal area, and a screw-retained monolithic zirconia prosthesis was fabricated. The patient also received a maxillary complete removable dental prosthesis over 4 anterior roots. At the 18-month follow-up, all of the zirconia cylinders were seen to be fractured, and the contacting abutment surfaces had lost structural integrity. The damaged abutments were replaced with new abutments, and a new prosthesis was delivered with a computer-assisted design and computer-assisted manufacturing fabricated titanium framework with denture teeth and denture base resins. At the 6-month recall, the patient did not have any problems. Dental zirconia has excellent physical properties; however, care should be taken to prevent excessive stresses on the zirconia cylinders when a screw-retained zirconia restoration is planned as a definitive prosthesis.

  16. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  17. Large area monolithic organic solar cells

    NASA Astrophysics Data System (ADS)

    Jin, Hui; Tao, Cheng; Hambsch, Mike; Pivrikas, Almantas; Velusamy, Marappan; Aljada, Muhsen; Zhang, Yuliang; Burn, Paul L.; Meredith, Paul

    2012-11-01

    Although efficiencies of > 10% have recently been achieved in laboratory-scale organic solar cells, these competitive performance figures are yet to be translated to large active areas and geometries relevant for viable manufacturing. One of the factors hindering scale-up is a lack of knowledge of device physics at the sub-module level, particularly cell architecture, electrode geometry and current collection pathways. A more in depth understanding of how photocurrent and photovoltage extraction can be optimised over large active areas is urgently needed. Another key factor suppressing conversion efficiencies in large area cells is the relatively high sheet resistance of the transparent conducting anode - typically indium tin oxide. Hence, to replace ITO with alternative transparent conducting anodes is also a high priority on the pathway to viable module-level organic solar cells. In our paper we will focus on large area devices relevant to sub-module scales - 5 cm × 5 cm monolithic geometry. We have applied a range of experimental techniques to create a more comprehensive understanding of the true device physics that could help make large area, monolithic organic solar cells more viable. By employing this knowledge, a novel transparent anode consisting of molybdenum oxide (MoOx) and silver (Ag) is developed to replace ITO and PEDOT-free large area solar cell sub-modules, acting as both a transparent window and hole-collecting electrode. The proposed architecture and anode materials are well suited to high throughput, low cost all-solution processing.

  18. Monolithic columns in plant proteomics and metabolomics.

    PubMed

    Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

    2013-03-01

    Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.

  19. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kristensen, K.; Enggrob, K. L.; King, S. M.; Worton, D. R.; Platt, S. M.; Mortensen, R.; Rosenoern, T.; Surratt, J. D.; Bilde, M.; Goldstein, A. H.; Glasius, M.

    2013-04-01

    The formation of carboxylic acids and dimer esters from α-pinene oxidation was investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX). Chamber experiments of α-pinene ozonolysis in dry air and at low NOx concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358) and pinonyl-pinyl dimer ester (MW 368), under both low- and high-temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation products cis-pinic and terpenylic acids, but similar to the second-generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). Dimer esters were observed within the first 30 min, indicating rapid production simultaneous to their structural precursors. However, the sampling time resolution precluded conclusive evidence regarding formation from gas- or particle-phase processes. CCN activities of the particles formed in the smog chamber displayed a modest variation during the course of experiments, with κ values in the range 0.06-0.09 (derived at a supersaturation of 0.19%). The pinyl-diaterpenyl dimer ester was also observed in ambient aerosol samples collected above a ponderosa pine forest in the Sierra Nevada Mountains of California during two seasonally distinct field campaigns in September 2007 and July 2009. The pinonyl-pinyl ester was observed for the first time in ambient air during the 2009 campaign, and although present at much lower concentrations, it was correlated with the abundance of the pinyl-diaterpenyl ester, suggesting similarities in their formation. The maximum concentration of the pinyl-diaterpenyl ester was almost 10 times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation with levels of

  20. Fluorescence formation from the interaction of DNA with lipid oxidation degradation products.

    PubMed

    Frankel, E N; Neff, W E; Brooks, D D; Fujimoto, K

    1987-06-23

    To clarify the mechanism of fluorescence formation between DNA and lipid degradation products in the presence of ferric chloride and ascorbic acid, a number of carbonyl compounds and decomposition products of pure methyl linolenate hydroperoxides were examined. Keto derivatives of methyl ricinoleate, linoleate, and oleate, alkanals and 2-alkenals produced little or no fluorescence with DNA in the presence of ferric chloride-ascorbic acid. 2,4-Alkadienals were more active and 2,4,7-decatrienal was the most active. Mixtures of volatile aldehydes prepared from linolenate hydroperoxide decomposed either thermally or with iron and ascorbate had the same activity as 2,4,7-decatrienal. Higher molecular-weight products from the decomposition of methyl linolenate hydroperoxides showed relatively low activity. beta-Carotene, alpha-tocopherol and other antioxidants effectively reduced the amount of fluorescence formed by linolenate hydroperoxides. The results suggest that, in addition to hydroperoxide decomposition products, singlet oxygen and/or free radical species contribute significantly to the fluorescence formed from the interaction of methyl linolenate hydroperoxides with DNA in the presence of ferric chloride and ascorbic acid.

  1. Effects of encapsulation of microorganisms on product formation during microbial fermentations.

    PubMed

    Westman, Johan O; Ylitervo, Päivi; Franzén, Carl Johan; Taherzadeh, Mohammad J

    2012-12-01

    This paper reviews the latest developments in microbial products by encapsulated microorganisms in a liquid core surrounded by natural or synthetic membranes. Cells can be encapsulated in one or several steps using liquid droplet formation, pregel dissolving, coacervation, and interfacial polymerization. The use of encapsulated yeast and bacteria for fermentative production of ethanol, lactic acid, biogas, L-phenylacetylcarbinol, 1,3-propanediol, and riboflavin has been investigated. Encapsulated cells have furthermore been used for the biocatalytic conversion of chemicals. Fermentation, using encapsulated cells, offers various advantages compared to traditional cultivations, e.g., higher cell density, faster fermentation, improved tolerance of the cells to toxic media and high temperatures, and selective exclusion of toxic hydrophobic substances. However, mass transfer through the capsule membrane as well as the robustness of the capsules still challenge the utilization of encapsulated cells. The history and the current state of applying microbial encapsulation for production processes, along with the benefits and drawbacks concerning productivity and general physiology of the encapsulated cells, are discussed.

  2. Formaldehyde Reactions with Amines and Ammonia: Particle Formation and Product Identification

    NASA Astrophysics Data System (ADS)

    Galloway, M. M.; Millage, K. D.; Rodriguez, A.; Sedehi, N.; Powelson, M. H.; De Haan, D. O.

    2012-12-01

    Aqueous phase reactions between carbonyls and amines or ammonium salts have recently been implicated in secondary organic aerosol and brown carbon formation processes. Formaldehyde is ubiquitous in the atmosphere, and is present in both the gas and aqueous phases. However, the reactions of formaldehyde in the aqueous phase have not been completely characterized. This study aims to determine the interactions between formaldehyde and amines or ammonium salts present in atmospheric droplets. Bulk phase reactions of formaldehyde with these reactive nitrogen-containing compounds were monitored with ESI-MS and NMR to determine reaction kinetics and for product characterization, while UV-Vis spectroscopy was used to monitor changes in light absorption over time. Hexamethylenetetramine was found to be a major product of the formaldehyde/ammonium sulfate reaction, appearing within minutes of mixing. No products were formed that absorbed light beyond 225 nm. Mono-disperse particles containing mixtures of formaldehyde and ammonium sulfate or an amine were dried and analyzed via SMPS to determine the non-volatile fraction of the reaction products. Similarly, aqueous droplets were dried in a humid atmosphere to determine residual aerosol sizes over time as a function of formaldehyde concentration. This work indicates that formaldehyde plays a key role in aqueous-phase organic processing, as it has been observed to contribute to both an increase and reduction in the diameter and volume of residual aerosol particles.

  3. Advanced glycoxidation and lipoxidation end products (AGEs and ALEs): an overview of their mechanisms of formation.

    PubMed

    Vistoli, G; De Maddis, D; Cipak, A; Zarkovic, N; Carini, M; Aldini, G

    2013-08-01

    Advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs) have a pathogenetic role in the development and progression of different oxidative-based diseases including diabetes, atherosclerosis, and neurological disorders. AGEs and ALEs represent a quite complex class of compounds that are formed by different mechanisms, by heterogeneous precursors and that can be formed either exogenously or endogenously. There is a wide interest in AGEs and ALEs involving different aspects of research which are essentially focused on set-up and application of analytical strategies (1) to identify, characterize, and quantify AGEs and ALEs in different pathophysiological conditions; (2) to elucidate the molecular basis of their biological effects; and (3) to discover compounds able to inhibit AGEs/ALEs damaging effects not only as biological tools aimed at validating AGEs/ALEs as drug target, but also as promising drugs. All the above-mentioned research stages require a clear picture of the chemical formation of AGEs/ALEs but this is not simple, due to the complex and heterogeneous pathways, involving different precursors and mechanisms. In view of this intricate scenario, the aim of the present review is to group the main AGEs and ALEs and to describe, for each of them, the precursors and mechanisms of formation.

  4. Inhibitory effects of hydroxysafflor yellow A on the formation of advanced glycation end products in vitro.

    PubMed

    Ni, Zhenzhen; Zhuge, Zhengbing; Li, Wenlu; Xu, Huimin; Zhang, Zhongmiao; Dai, Haibin

    2012-01-01

    To investigate the inhibitory effects of hydroxysafflor yellow A (HSYA) on the protein glycation in vitro. Using bovine serum albumin (BSA)-glucose assay, BSA-methylglyoxal (MGO) assay, and N-acetylglycyl-lysine methyl ester (G.K.) peptide-ribose assay, inhibitory effects of HSYA were investigated. Advanced glycation end products (AGEs) production was assessed by AGEs-specific fluorescence and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In BSA-glucose assay, HSYA concentration dependently decreased AGEs formation, with maximum inhibitory effects at 1 mM by 95%. Further more, HSYA also showed significant inhibitory effects on MGO-medicated protein modification and subsequent cross-linking of proteins. Finally, when co-incubated with G.K. peptide and ribose, HSYA exhibited its antiglycation effects, and the maximum inhibitory effects of HSYA at 1 mM were 84%. Overall, our present study provides the first evidence of the antiglycation effects of HSYA on AGEs formation in vitro.

  5. Effect of chlorine dioxide on cyanobacterial cell integrity, toxin degradation and disinfection by-product formation.

    PubMed

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Li, Lei; Deng, Jing; Zhu, Mingqiu; Zhu, Shumin

    2014-06-01

    Bench scale tests were conducted to study the effect of chlorine dioxide (ClO2) oxidation on cell integrity, toxin degradation and disinfection by-product formation of Microcystis aeruginosa. The simulated cyanobacterial suspension was prepared at a concentration of 1.0×10(6)cells/mL and the cell integrity was measured with flow cytometry. Results indicated that ClO2 can inhibit the photosynthetic capacity of M. aeruginosa cells and almost no integral cells were left after oxidation at a ClO2 dose of 1.0mg/L. The total toxin was degraded more rapidly with the ClO2 dosage increasing from 0.1mg/L to 1.0mg/L. Moreover, the damage on cell structure after oxidation resulted in released intracellular organic matter, which contributed to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) as disinfection by-products. Therefore, the use of ClO2 as an oxidant for treating algal-rich water should be carefully considered.

  6. Impacts of drinking water pretreatments on the formation of nitrogenous disinfection by-products.

    PubMed

    Chu, Wenhai; Gao, Naiyun; Deng, Yang; Templeton, Michael R; Yin, Daqiang

    2011-12-01

    The formation of disinfection by-products (DBPs), including both nitrogenous DBPs (N-DBPs) and carbonaceous DBPs (C-DBPs), was investigated by analyzing chlorinated water samples following the application of three pretreatment processes: (i) powdered activated carbon (PAC) adsorption; (ii) KMnO(4) oxidation and (iii) biological contact oxidation (BCO), coupled with conventional water treatment processes. PAC adsorption can remove effectively the precursors of chloroform (42.7%), dichloroacetonitrile (28.6%), dichloroacetamide (DCAcAm) (27.2%) and trichloronitromethane (35.7%), which were higher than that pretreated by KMnO(4) oxidation and/or BCO process. The removal efficiency of dissolved organic carbon by BCO process (76.5%)--was superior to that by PAC adsorption (69.9%) and KMnO(4) oxidation (61.4%). However, BCO increased the dissolved organic nitrogen (DON) concentration which caused more N-DBPs to be formed during subsequent chlorination. Soluble microbial products including numerous DON compounds were produced in the BCO process and were observed to play an essential role in the formation of DCAcAm in particular.

  7. Rhodomyrtone inhibits lipase production, biofilm formation, and disorganizes established biofilm in Propionibacterium acnes.

    PubMed

    Wunnoo, Suttiwan; Saising, Jongkon; Voravuthikunchai, Supayang Piyawan

    2017-02-01

    Virulence enzymes and biofilm a play crucial role in the pathogenesis of Propionibacterium acnes, a major causative agent of acne vulgaris. In the present study, the effects of rhodomyrtone, a pure compound identified from Rhodomyrtus tomentosa (Aiton) Hassk. leaves extract against enzyme production and biofilm formation production by 5 clinical isolates and a reference strain were evaluated. The degree of hydrolysis by both lipase and protease enzymes significantly decreased upon treatment with the compound at 0.125-0.25 μg/mL (p < 0.05). Lipolytic zones significantly reduced in all isolates while decrease in proteolytic activities was found only in 50% of the isolates. Rhodomyrtone at 1/16MIC and 1/8MIC caused significant reduction in biofilm formation of the clinical isolates (p < 0.05). Percentage viability of P. acnes within mature biofilm upon treated with the compound at 4MIC and 8MIC ranged between 40% and 85%. Pronounced properties of rhodomyrtone suggest a path towards developing a novel anti-acne agent.

  8. The enamel matrix derivative (Emdogain) enhances human tongue carcinoma cells gelatinase production, migration and metastasis formation.

    PubMed

    Laaksonen, Matti; Suojanen, Juho; Nurmenniemi, Sini; Läärä, Esa; Sorsa, Timo; Salo, Tuula

    2008-08-01

    Enamel matrix derivative Emdogain (EMD) is widely used in periodontal treatment to regenerate lost connective tissue and to improve the attachment of the teeth. Gelatinases (MMP-2 and -9) have an essential role in the promotion and progression of oral cancer growth and metastasis formation. We studied the effects of EMD on human tongue squamous cell carcinoma (HSC-3) cells in vitro and in vivo. In vitro, EMD (100 microg/ml and 200 microg/ml) remarkably induced the MMP-2 and -9 production from HSC-3 cells analysed by zymography and enzyme-linked immunosorbent assay. EMD also slightly induced the MMP-2 and -9 production from benign human mucosal keratinocytes (HMK). Furthermore, EMD clearly induced the transmigration of HSC-3 cells but had no effect on the HMK migration in transwell assays. The in vitro wound closure of HSC-3 cells was notably accelerated by EMD, whereas it had only minor effect on the wound closure of HMKs. The migration of both cell lines was inhibited by a selective cyclic anti-gelatinolytic peptide CTT-2. EMD had no effect on HSC-3 cell proliferation or apoptosis and only a limited effect on cell attachment to various extracellular matrix components. The in vivo mice experiment revealed that EMD substantially induced HSC-3 xenograft metastasis formation. Our results suggest that the use of EMD for patients with oral mucosal carcinomas or premalignant lesions should be carefully considered, possibly avoided.

  9. Ionic liquid effects on a multistep process. Increased product formation due to enhancement of all steps.

    PubMed

    Keaveney, Sinead T; Haines, Ronald S; Harper, Jason B

    2015-09-07

    The reaction of a series of substituted benzaldehydes with hexylamine was examined in acetonitrile and an ionic liquid. In acetonitrile, as the electron withdrawing nature of the substituent increases, the overall addition-elimination process becomes faster as does the build-up of the aminol intermediate. Under equivalent conditions in an ionic liquid, less intermediate build up is observed, and the effect on the rate on varying the substituent is different to that in acetonitrile. Extensive kinetic analysis shows that the ionic liquid solvent increases the rate constant of all steps of the reaction, resulting in faster product formation relative to acetonitrile; these effects increase with the proportion of ionic liquid in the reaction mixture. Differences in the equilibrium position of the addition step in the ionic liquid were found to account for both the decrease in intermediate build up relative to acetonitrile, as well as the differing trend in the overall rate of product formation as the substituent was changed. The microscopic origins of these ionic liquid effects were probed through temperature dependent analyses, highlighting the subtle balance of interactions between the ionic liquid and species along the reaction coordinate, particularly the importance of charge development in the transition state.

  10. Histamine Formation in a Dry Salted Twaite Shad ( Alosa fallax lacustris ) Product.

    PubMed

    Vasconi, Mauro; Bellagamba, Federica; Bernardi, Cristian; Martino, Piera Anna; Moretti, Vittorio Maria

    2017-01-01

    Landlocked shad is a freshwater clupeid fish ( Alosa fallax lacustris ) whose consumption is associated with the risk of scombrotoxin poisoning. Traditionally, fresh shad are subjected to an artisanal processing procedure, consisting of dry salting and maturation under pressure, to give a fish product named missoltino , which is stored in large metallic barrels and is sold to local consumers and restaurants. In recent years, the introduction of modern food packaging technologies has enabled this product to also be distributed in shops and supermarkets. Consequently, the determination of the safety of this product is an urgent issue. The aims of the present research were to measure histamine levels and histamine-forming bacteria in shad products collected at different phases of preparation and ripening, in order to minimize poison hazards, to provide technical information about risk, and to standardize the production process. One hundred twenty-six samples of shad (21 fresh fish and 105 dried) at different phases of preparation and ripening were collected from seven producers and were analyzed for chemical composition, histamine content, and microbiological properties. After 130 days of ripening, samples from three producers presented unacceptable amounts of histamine (>200 mg/kg), according to European Union legislation. A moderate negative correlation was found between histamine levels and salt content (r =-0.504, P < 0.01) and between histamine levels and water phase salt content (r =-0.415, P < 0.01). Several bacterial strains that were positive on Niven's medium were isolated during the early phases of production, whereas the extreme environment of salted shad at the end of ripening led to a drastic decrease of bacteria, but not of histamine. The most effective preventive measures for histamine formation and accumulation in salted shad were strictly related to fish handling and storage conditions during processing.

  11. Effects of hydrogen partial pressure on autotrophic growth and product formation of Acetobacterium woodii.

    PubMed

    Kantzow, Christina; Weuster-Botz, Dirk

    2016-08-01

    Low aqueous solubility of the gases for autotrophic fermentations (e.g., hydrogen gas) results in low productivities in bioreactors. A frequently suggested approach to overcome mass transfer limitation is to increase the solubility of the limiting gas in the reaction medium by increasing the partial pressure in the gas phase. An increased inlet hydrogen partial pressure of up to 2.1 bar (total pressure of 3.5 bar) was applied for the autotrophic conversion of hydrogen and carbon dioxide with Acetobacterium woodii in a batch-operated stirred-tank bioreactor with continuous gas supply. Compared to the autotrophic batch process with an inlet hydrogen partial pressure of 0.4 bar (total pressure of 1.0 bar) the final acetate concentration after 3.1 days was reduced to 50 % (29.2 g L(-1) compared to 59.3 g L(-1)), but the final formate concentration was increased by a factor of 18 (7.3 g L(-1) compared to 0.4 g L(-1)). Applying recombinant A. woodii strains overexpressing either genes for enzymes in the methyl branch of the Wood-Ljungdahl pathway or the genes phosphotransacetylase and acetate kinase at an inlet hydrogen partial pressure of 1.4 bar reduced the final formate concentration by up to 40 % and increased the final dry cell mass and acetate concentrations compared to the wild type strain. Solely the overexpression of the two genes for ATP regeneration at the end of the Wood-Ljungdahl pathway resulted in an initial switch off of formate production at increased hydrogen partial pressure until the maximum of the hydrogen uptake rate was reached.

  12. Effect of magnetic ion exchange and ozonation on disinfection by-product formation.

    PubMed

    Kingsbury, Ryan S; Singer, Philip C

    2013-03-01

    The purpose of this research was to investigate the performance of treatment with magnetic ion exchange (MIEX) resin followed by ozonation in achieving disinfection goals while controlling bromate and chlorinated disinfection by-product (DBP) formation. Three water samples were collected from raw water supplies impacted by the San Francisco Bay Delta to represent the varying levels of bromide and total organic carbon (TOC) that occur throughout the year. A fourth water was prepared by spiking bromide into a portion of one of the samples. Samples of each water were pre-treated with alum or virgin MIEX resin, and the raw and treated waters were subsequently ozonated under semi-batch conditions to assess the impact of treatment on ozone demand, ozone exposure for disinfection ("CT"), and bromate formation. Finally, aliquots of raw, coagulated, resin-treated, and ozonated waters were chlorinated in order to measure trihalomethane formation potential (THMFP). In the waters studied, MIEX resin removed 41-68% of raw water TOC, compared to 12-44% for alum. MIEX resin also reduced the bromide concentration by 20-50%. The removal of TOC by alum and MIEX resin significantly reduced the ozone demand of all waters studied, resulting in higher dissolved ozone concentrations and CT values for a given amount of ozone transferred into solution. For a given level of disinfection (CT), the amount of bromate produced by ozonation of MIEX-treated waters was similar to or slightly less than that of raw water and significantly less than that of alum-treated water. MIEX resin removed 39-85% of THMFP compared to 16-56% removal by alum. Ozonation reduced THMFP by 35-45% in all cases. This work indicates that in bromide-rich waters in which ozone disinfection is used, MIEX resin is a more appropriate treatment than alum for the removal of organic carbon, as it achieves superior TOC and THM precursor removal and decreases the production of bromate from ozone.

  13. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

    PubMed Central

    Smeltink, M. W.; Straathof, A. J. J.; Paasman, M. A.; van de Sandt, E. J. A. X.; Kapteijn, F.; Moulijn, J. A.

    2008-01-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l−1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml−1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml−1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s−1 m−3monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s−1 m−3catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different

  14. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice

    PubMed Central

    Tamarat, Radia; Silvestre, Jean-Sébastien; Huijberts, Maya; Benessiano, Joelle; Ebrahimian, Teni G.; Duriez, Micheline; Wautier, Marie-Paule; Wautier, Jean Luc; Lévy, Bernard I.

    2003-01-01

    We hypothesized that formation of advanced glycation end products (AGEs) associated with diabetes reduces matrix degradation by metalloproteinases (MMPs) and contributes to the impairment of ischemia-induced angiogenesis. Mice were treated or not with streptozotocin (40 mg/kg) and streptozotocin plus aminoguanidine (AGEs formation blocker, 50 mg/kg). After 8 weeks of treatment, hindlimb ischemia was induced by right femoral artery ligature. Plasma AGE levels were strongly elevated in diabetic mice when compared with control mice (579 ± 21 versus 47 ± 4 pmol/ml, respectively; P < 0.01). Treatment with aminoguanidine reduced AGE plasma levels when compared with untreated diabetic mice (P < 0.001). After 28 days of ischemia, ischemic/nonischemic leg angiographic score, capillary density, and laser Doppler skin-perfusion ratios were 1.4-, 1.5-, and 1.4-fold decreased in diabetic mice in reference to controls (P < 0.01). Treatment with aminoguanidine completely normalized ischemia-induced angiogenesis in diabetic mice. We next analyzed the role of proteolysis in AGE formation-induced hampered neovascularization process. After 3 days of ischemia, MMP-2 activity and MMP-3 and MMP-13 protein levels were increased in untreated and aminoguanidine-treated diabetic mice when compared with controls (P < 0.05). Despite this activation of the MMP pathway, collagenolysis was decreased in untreated diabetic mice. Conversely, treatment of diabetic mice with aminoguanidine restored collagenolysis toward levels found in control mice. In conclusion, blockade of AGE formation by aminoguanidine normalizes impaired ischemia-induced angiogenesis in diabetic mice. This effect is probably mediated by restoration of matrix degradation processes that are disturbed as a result of AGE accumulation. PMID:12805564

  15. Blockade of advanced glycation end-product formation restores ischemia-induced angiogenesis in diabetic mice.

    PubMed

    Tamarat, Radia; Silvestre, Jean-Sébastien; Huijberts, Maya; Benessiano, Joelle; Ebrahimian, Teni G; Duriez, Micheline; Wautier, Marie-Paule; Wautier, Jean Luc; Lévy, Bernard I

    2003-07-08

    We hypothesized that formation of advanced glycation end products (AGEs) associated with diabetes reduces matrix degradation by metalloproteinases (MMPs) and contributes to the impairment of ischemia-induced angiogenesis. Mice were treated or not with streptozotocin (40 mg/kg) and streptozotocin plus aminoguanidine (AGEs formation blocker, 50 mg/kg). After 8 weeks of treatment, hindlimb ischemia was induced by right femoral artery ligature. Plasma AGE levels were strongly elevated in diabetic mice when compared with control mice (579 +/- 21 versus 47 +/- 4 pmol/ml, respectively; P < 0.01). Treatment with aminoguanidine reduced AGE plasma levels when compared with untreated diabetic mice (P < 0.001). After 28 days of ischemia, ischemic/nonischemic leg angiographic score, capillary density, and laser Doppler skin-perfusion ratios were 1.4-, 1.5-, and 1.4-fold decreased in diabetic mice in reference to controls (P < 0.01). Treatment with aminoguanidine completely normalized ischemia-induced angiogenesis in diabetic mice. We next analyzed the role of proteolysis in AGE formation-induced hampered neovascularization process. After 3 days of ischemia, MMP-2 activity and MMP-3 and MMP-13 protein levels were increased in untreated and aminoguanidine-treated diabetic mice when compared with controls (P < 0.05). Despite this activation of the MMP pathway, collagenolysis was decreased in untreated diabetic mice. Conversely, treatment of diabetic mice with aminoguanidine restored collagenolysis toward levels found in control mice. In conclusion, blockade of AGE formation by aminoguanidine normalizes impaired ischemia-induced angiogenesis in diabetic mice. This effect is probably mediated by restoration of matrix degradation processes that are disturbed as a result of AGE accumulation.

  16. Thermal cycling effect in U-10Mo/Zry-4 monolithic nuclear fuel

    NASA Astrophysics Data System (ADS)

    Lopes, Denise A.; Zimmermann, Angelo J. O.; Silva, Selma L.; Piqueira, J. R. C.

    2016-05-01

    Uranium alloys in a monolithic form have been considered attractive candidates for high density nuclear fuel. However, this high-density fissile material configuration keeps the volume permitted for the retention of fission products at a minimum. Additionally, the monolithic nuclear fuel has a peculiar configuration, whereby the fuel is in direct contact with the cladding. How this fuel configuration will retain fission products and how this will affect its integrity under various physical conditions - such as thermal cycling - are some of the technological problems for this new fuel. In this paper, the effect of out-of-pile thermal cycling is studied for a monolithic fuel plate produced by a hot co-rolling method using U-10Mo (wt %) as the fuel alloy and Zircaloy-4 as the cladding material. After performing 10 thermal cycles from 25 to 400 °C at a rate of 1 °C/min (∼125 h), the fuel alloy presented several fractures that were observed to occur in the last three cycles. These cracks nucleated approximately in the center of the fuel alloy and crossed the interdiffusion zone initiating an internal crack in the cladding. The results suggest that the origin of these fractures is the thermal fatigue of the U-10Mo alloy caused due to the combination of two factors: (i) the high difference in the thermal expansion coefficient of the fuel and of the cladding material, and (ii) the bound condition of fuel/cladding materials in this fuel element configuration.

  17. Novel porous fly-ash containing geopolymer monoliths for lead adsorption from wastewaters.

    PubMed

    Novais, Rui M; Buruberri, L H; Seabra, M P; Labrincha, J A

    2016-11-15

    In this study novel porous biomass fly ash-containing geopolymer monoliths were produced using a simple and flexible procedure. Geopolymers exhibiting distinct total porosities (ranging from 41.0 to 78.4%) and low apparent density (between 1.21 and 0.44g/cm(3)) were fabricated. Afterwards, the possibility of using these innovative materials as lead adsorbents under distinct conditions was evaluated. Results demonstrate that the geopolymers' porosity and the pH of the ion solution strongly affect the lead adsorption capacity. Lead adsorption by the geopolymer monoliths ranged between 0.95 and 6.34mglead/ggeopolymer. More porous geopolymers presented better lead removal efficiency, while higher pH in the solution reduced their removal ability, since metal precipitation is enhanced. These novel geopolymeric monoliths can be used in packed beds that are easily collected when exhausted, which is a major advantage in comparison with the use of powdered adsorbents. Furthermore, their production encompasses the reuse of biomass fly-ash, mitigating the environmental impact associated with this waste disposal, while decreasing the adsorbents production costs.

  18. Monolithic 3D-ICs with single grain Si thin film transistors

    NASA Astrophysics Data System (ADS)

    Ishihara, R.; Derakhshandeh, J.; Tajari Mofrad, M. R.; Chen, T.; Golshani, N.; Beenakker, C. I. M.

    2012-05-01

    Monolithic 3D integration is the ultimate approach in 3D-ICs as it provides high-density and submicron vertical interconnects and hence transistor level integration. Here, high-quality Si layer formation at a low temperature is a key challenge. We review our recent achievements in monolithic 3D-ICs based on single-grain Si TFTs that are fabricated inside a single-grain with a low-temperature process. With the μ-Czochralski process based on a pulsed-laser crystallization, Si grains with a diameter of 6 μm are successfully formed on predetermined positions. Single-grain (SG) Si TFTs are fabricated inside the single-grain with mobility for electron and holes of 600 cm2/V s and 200 cm2/V s, respectively. Two layers of the SG Si TFT were vertically stacked and successfully implemented into CMOS inverter, 3D 6T-SRAM and single-grain lateral PIN photo-diode with in-pixel amplifier. Those results indicate that the SG TFTs are attractive for use in monolithic 3D-ICs on an arbitrary substrate including a glass and even a plastic for applications such as ultra-high-density memories, logic-to-logic integration, CPU integrated display, and high-definition image sensor for artificial retina.

  19. Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides.

    PubMed

    Lamprou, Alexandros; Wang, Hongxia; Saeed, Adeela; Svec, Frantisek; Britt, David; Maya, Fernando

    2015-07-14

    We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process. The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

  20. oVOC production from tropospheric alkyne oxidation and contribution to aerosol formation and growth

    NASA Astrophysics Data System (ADS)

    Goodall, Iain

    2013-04-01

    Ethyne (C2H2) is one of the simplest volatile organic compounds (VOC) and is predominantly emitted via anthropogenic processes and reacts with nitrogen oxides (NOx) in the presence of sunlight to form tropospheric ozone (O3). The dominant oxidation product of ethyne is the dicarbonyl species glyoxal (CHOCHO), which is thought to be a significant contributor to secondary organic aerosol (SOA) formation via irreversible oligomerisation reactions upon the surface of hydrated aerosol particulates and within cloud droplets. A series of chamber experiments were performed at the EUPHORE facility (Valencia, Spain) to study the atmospheric oxidation of ethyne, to determine oxidation product yields and to monitor SOA formation and growth by dicarbonyl oligomerisation. A Proton Transfer Reaction-Time of Flight- Mass Spectrometer (PTR-ToF-MS) was deployed by the University of Leicester to monitor precursor decay and the subsequent evolution of any gas-phase oxidised volatile organic compounds (oVOC). This was further complemented by a Broadband Cavity Enhanced Absorption Spectrometer (BBCEAS) for specific dicarbonyl and NO2 measurements. Aqueous extracts of chamber SOA were taken from filters collected during the experiments and subsequently analysed offline. The work explores the yields of low molecular weight products of ethyne oxidation for light and dark reactions, with varying levels of NOx and OH. Novel experiments were performed under atmospherically relevant conditions utilising natural lighting rather than artificial lighting. Reaction yields have been assessed with the aim of contributing to the ethyne and glyoxal mechanisms in the Master Chemical Mechanism (MCM; http://mcm.leeds.ac.uk/MCM), and have been compared with previously reported values determined from experiments performed under artificial lighting conditions.

  1. FOAM FORMATION IN THE SALTSTONE PRODUCTION FACILITY: EVALUATION OF SOURCES AND MITIGATION

    SciTech Connect

    Cozzi, A.

    2011-01-18

    The Saltstone Production Facility receives waste from Tank 50H for treatment. Influents into Tank 50H include the Effluent Treatment Project waste concentrate, H-Canyon low activity waste and General Purpose Evaporator bottoms, Modular Caustic Side Solvent Extraction Unit decontaminated salt solution, and salt solution from the Deliquification, Dissolution and Adjust campaign. Using the Waste Characterization System (WCS), this study tracks the relative amounts of each influent into Tank 50H, as well as the total content of Tank 50H, in an attempt to identify the source of foaming observed in the Saltstone Production Facility hopper. Saltstone has been using antifoam as part of routine processing with the restart of the facility in December 2006. It was determined that the maximum admix usage in the Saltstone Production Facility, both antifoam and set retarder, corresponded with the maximum concentration of H-Canyon low activity waste in Tank 50H. This paper also evaluates archived salt solutions from Waste Acceptance Criteria analysis for propensity to foam and the antifoam dosage required to mitigate foaming. It was determined that Effluent Treatment Project contributed to the expansion factor (foam formation) and General Purpose Evaporator contributed to foaminess (persistence). It was also determined that undissolved solids contribute to foam persistence. It was shown that additions of Dow Corning Q2-1383a antifoam reduced both the expansion factor and foaminess of salt solutions. The evaluation of foaming in the grout hopper during the transition from water to salt solution indicated that higher water-to-premix ratios tended to produce increased foaming. It was also shown that additions of Dow Corning Q2-1383a antifoam reduced foam formation and persistence.

  2. Compressible, Dense, Three-Dimensional Holey Graphene Monolithic Architecture.

    PubMed

    Han, Xiaogang; Yang, Zhi; Zhao, Bin; Zhu, Shuze; Zhou, Lihui; Dai, Jiaqi; Kim, Jae-Woo; Liu, Boyang; Connell, John W; Li, Teng; Yang, Bao; Lin, Yi; Hu, Liangbing

    2017-03-10

    By creating holes in 2D nanosheets, tortuosity and porosity can be greatly tunable, which enables a fast manufacturing process (i.e., fast removal of gas and solvent) toward various nanostructures. We demonstrated outstanding compressibility of holey graphene nanosheets, which is impossible for pristine graphene. Holey graphene powder can be easily compressed into dense and strong monoliths with different shapes at room temperature without using any solvents or binders. The remarkable compressibility of holey graphene, which is in sharp contrast with pristine graphene, not only enables the fabrication of robust, dense graphene products that exhibit high density (1.4 g/cm(3)), excellent specific mechanical strength [18 MPa/(g/cm(3))], and good electrical (130 S/cm) and thermal (20 W/mK) conductivities, but also provides a binder-free dry process that overcomes the disadvantages of wet processes required for fabrication of three-dimensional graphene products. Fundamentally different from graphite, the holey graphene products are both dense and porous, which can enable possible broader applications such as energy storage and gas separation membranes.

  3. Thin film CIGS photovoltaic modules: monolithic integration and advanced packaging for high performance, high reliability and low cost

    NASA Astrophysics Data System (ADS)

    Eldada, Louay

    2011-01-01

    In recent years, thin-film photovoltaic companies started realizing their low manufacturing cost potential, and have been grabbing an increasingly larger market share. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, and a fast high-quality CIGS reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable cover plates in the first stage, while in the second stage the CIGS layer is formed by rapid heating with Se confinement. HelioVolt also developed best-in-class packaging technologies that provide unparalleled environmental stability. High quality CIGS films with large grains were fabricated on the production line, and high-performance highreliability monolithic modules with a form factor of 120 cm × 60 cm are being produced at high yield and low cost. With conversion efficiency levels around 14% for cells and 12% for modules, HelioVolt is commercializing the process on its first production line with 20 MW capacity, and is planning its next GW-scale factory.

  4. The Cell Factory Aspergillus Enters the Big Data Era: Opportunities and Challenges for Optimising Product Formation.

    PubMed

    Meyer, Vera; Fiedler, Markus; Nitsche, Benjamin; King, Rudibert

    2015-01-01

    Living with limits. Getting more from less. Producing commodities and high-value products from renewable resources including waste. What is the driving force and quintessence of bioeconomy outlines the lifestyle and product portfolio of Aspergillus, a saprophytic genus, to which some of the top-performing microbial cell factories belong: Aspergillus niger, Aspergillus oryzae and Aspergillus terreus. What makes them so interesting for exploitation in biotechnology and how can they help us to address key challenges of the twenty-first century? How can these strains become trimmed for better growth on second-generation feedstocks and how can we enlarge their product portfolio by genetic and metabolic engineering to get more from less? On the other hand, what makes it so challenging to deduce biological meaning from the wealth of Aspergillus -omics data? And which hurdles hinder us to model and engineer industrial strains for higher productivity and better rheological performance under industrial cultivation conditions? In this review, we will address these issues by highlighting most recent findings from the Aspergillus research with a focus on fungal growth, physiology, morphology and product formation. Indeed, the last years brought us many surprising insights into model and industrial strains. They clearly told us that similar is not the same: there are different ways to make a hypha, there are more protein secretion routes than anticipated and there are different molecular and physical mechanisms which control polar growth and the development of hyphal networks. We will discuss new conceptual frameworks derived from these insights and the future scientific advances necessary to create value from Aspergillus Big Data.

  5. Concentration and purification of enterovirus 71 using a weak anion-exchange monolithic column

    PubMed Central

    2014-01-01

    Background Enterovirus 71 (EV-71) is a neurotropic virus causing Hand, Foot and Mouth Disease (HFMD) in infants and children under the age of five. It is a major concern for public health issues across Asia-Pacific region. The most effective way to control the disease caused by EV-71 is by vaccination thus a novel vaccine is urgently needed. Inactivated EV-71 induces a strong, virus-neutralizing antibody response in animal models, protecting them against a lethal EV-71 challenge and it has been shown to elicit cross-neutralizing antibodies in human trials. Hence, the large-scale production of purified EV-71 is required for vaccine development, diagnosis and clinical trials. Methods CIM® Monolith columns are single-piece columns made up of poly(glycidyl methacrylate co-ethylene dimethacrylate) as support matrix. They are designed as porous channels rather than beads with different chemistries for different requirements. As monolithic columns have a high binding capacity, flow rate and resolution, a CIM® DEAE-8f tube monolithic column was selected for purification in this study. The EV-71 infected Rhabdomyosarcoma (RD) cell supernatant was concentrated using 8% PEG 8000 in the presence of 400 mM sodium chloride. The concentrated virus was purified by weak anion exchange column using 50 mM HEPES + 1 M sodium chloride as elution buffer. Results Highly pure viral particles were obtained at a concentration of 350 mM sodium chloride as confirmed by SDS-PAGE and electron microscopy. Presence of viral proteins VP1, VP2 and VP3 was validated by western blotting. The overall process achieved a recovery of 55%. Conclusions EV-71 viral particles of up to 95% purity can be recovered by a single step ion-exchange chromatography using CIM-DEAE monolithic columns and 1 M sodium chloride as elution buffer. Moreover, this method is scalable to purify several litres of virus-containing supernatant, using industrial monolithic columns with a capacity of up to 8 L such as

  6. Formation of DNA adducts from oil-derived products analyzed by 32P-HPLC.

    PubMed

    Akkineni, L K; Zeisig, M; Baranczewski, P; Ekström, L G; Möller, L

    2001-01-01

    The aim of this study was to investigate the genotoxic potential of DNA adducts and to compare DNA adduct levels and patterns in petroleum vacuum distillates, coal tar distillate, bitumen fume condensates, and related substances that have a wide range of boiling temperatures. An in vitro assay was used for DNA adduct analysis with human and rat S-9 liver extract metabolic activation followed by 32P-postlabeling and 32P-high-performance liquid chromatography (32p-HPLC). For petroleum distillates originating from one crude oil there was a correlation between in vitro DNA adduct formation and mutagenic index, which showed an increase with a distillation temperature of 250 degrees C and a peak around a distillation point of approximately 400 degrees C. At higher temperatures, the genotoxicity (DNA adducts and mutagenicity) rapidly declined to very low levels. Different petroleum products showed a more than 100-fold range in DNA adduct formation, with severely hydrotreated base oil and bitumen fume condensates being lowest. Coal tar distillates showed ten times higher levels of DNA adduct formation than the most potent petroleum distillate. A clustered DNA adduct pattern was seen over a wide distillation range after metabolic activation with liver extracts of rat or human origin. These clusters were eluted in a region where alkylated aromatic hydrocarbons could be expected. The DNA adduct patterns were similar for base oil and bitumen fume condensates, whereas coal tar distillates had a wider retention time range of the DNA adducts formed. Reference substances were tested in the same in vitro assay. Two- and three-ringed nonalkylated aromatics were rather low in genotoxicity, but some of the three- to four-ringed alkylated aromatics were very potent inducers of DNA adducts. Compounds with an amino functional group showed a 270-fold higher level of DNA adduct formation than the same structures with a nitro functional group. The most potent DNA adduct inducers of the 16

  7. Identifying and Remediating High Water Production Problems in Basin-Centered Formations

    SciTech Connect

    R.L. Billingsley

    2005-12-01

    Through geochemical analyses of produced waters, petrophysics, and reservoir simulation we developed concepts and approaches for mitigating unwanted water production in tight gas reservoirs and for increasing recovery of gas resources presently considered noncommercial. Only new completion research (outside the scope of this study) will validate our hypothesis. The first task was assembling and interpreting a robust regional database of historical produced-water analyses to address the production of excessive water in basin-centered tight gas fields in the Greater Green (GGRB ) and Wind River basins (WRB), Wyoming. The database is supplemented with a sampling program in currently active areas. Interpretation of the regional water chemistry data indicates most produced waters reflect their original depositional environments and helps identify local anomalies related to basement faulting. After the assembly and evaluation phases of this project, we generated a working model of tight formation reservoir development, based on the regional nature and occurrence of the formation waters. Through an integrative approach to numerous existing reservoir concepts, we synthesized a generalized development scheme organized around reservoir confining stress cycles. This single overarching scheme accommodates a spectrum of outcomes from the GGRB and Wind River basins. Burial and tectonic processes destroy much of the depositional intergranular fabric of the reservoir, generate gas, and create a rock volume marked by extremely low permeabilities to gas and fluids. Stress release associated with uplift regenerates reservoir permeability through the development of a penetrative grain bounding natural fracture fabric. Reservoir mineral composition, magnitude of the stress cycle and local tectonics govern the degree, scale and exact mechanism of permeability development. We applied the reservoir working model to an area of perceived anomalous water production. Detailed water analyses

  8. Inhibition of the formation of advanced glycation end products by thymoquinone.

    PubMed

    Losso, Jack N; Bawadi, Hiba A; Chintalapati, Madhavi

    2011-09-01

    The inhibitory activity of thymoquinone, a major quinone from black seeds (Nigella sativa) against the formation of advanced glycation end products was studied using the hemoglobin-δ-gluconolactone, human serum albumin-glucose, and the N-acetyl-glycyl-lysine methyl ester-ribose assays. A comparison was made with the inhibitory activity of aminoguanidine. The cytotoxicity of thymoquinone was studied by the release of lactate dehydrogenase from platelets and the levels of plasma thiols. At 20μM, thymoquinone inhibited 39% of hemoglobin glycation, 82% of post-Amadori glycation products, reduced methyglyoxal-mediated human serum albumin glycation by 68%, inhibited 78% of late glycation end products. Aminoguanidine at 10mM was less effective than thymoquinone. The IC50 for thymoquinone and aminoguanidine were 7.2μM and 1.25mM, respectively. Thymoquinone at 20-50μM was not toxic to platelet lactate dehydrogenase and plasma thiols. The potential of thymoquinone in food applications is discussed.

  9. Manipulating respiratory levels in Escherichia coli for aerobic formation of reduced chemical products.

    PubMed

    Zhu, Jiangfeng; Sánchez, Ailen; Bennett, George N; San, Ka-Yiu

    2011-11-01

    Optimizing the productivity of bioengineered strains requires balancing ATP generation and carbon atom conservation through fine-tuning cell respiration and metabolism. Traditional approaches manipulate cell respiration by altering air feeding, which are technically difficult especially in large bioreactors. An approach based on genetic regulation may better serve this purpose. With excess oxygen supply to the culture, we efficiently manipulated Escherichia coli cell respiration by adding different amount of coenzyme Q1 to strains lacking the ubiCA genes, which encode two critical enzymes for ubiquinone synthesis. As a proof-of-concept, the metabolic effect of the ubiCA gene knockout and coenzyme Q1 supplementation were characterized, and the metabolic profiles of the experimental strains showed clear correlations with coenzyme Q1 concentrations. Further proof-of-principle experiments were performed to illustrate that the approach can be used to optimize cell respiration for the production of chemicals of interest such as ethanol. This study showed that controlled respiration through genetic manipulation can be exploited to allow much larger operating windows for reduced product formation even under fully aerobic conditions.

  10. [Degradation Kinetics and Formation of Disinfection By-products During Linuron Chlorination in Drinking Water].

    PubMed

    Ling, Xiao; Hu, Chen-yan; Cheng, Ming; Gu, Jian

    2015-05-01

    Chlorination degradation of linuron was studied using the common disinfectant sodium hypochlorite, the effects of chlorine dosage, pH value, bromine ion concentrationand temperature were systematically investigated, and the formation characteristics of disinfection by-products (DBPs) during the chlorination reaction was analyzed. The results showed that the chlorination degradation kinetics of linuron by sodium hypochlorite could be well described by the second-order kinetic model. Moreover, pH values had a great impact on the degradation reaction, and the rate constant reached the maximum level at pH 7, and the base elementary reaction rate constants of HOCl and OCl- with linuron were 4.84 x 10(2) L · (mol · h)(-1) and 3.80 x 10(2) L · (mol · h)(-1), respectively. The reaction rate decreased with the addition of bromide ion and increased with increasing temperature. Furthermore, many kinds of disinfection by- products were produced during the chlorination degradation of linuron, including CF, DCAN, TCNM and halogen acetone. Under conditions of different solution pH and different bromide ion concentrations, there would be significant difference in the types and concentrations of disinfection by-products.

  11. Atmospheric Oxidation Mechanisms for Diethyl Ether and its Oxidation Products, Ethyl Formate and Ethyl Acetate.

    NASA Astrophysics Data System (ADS)

    Orlando, J. J.; Tyndall, G. S.

    2006-12-01

    Carbon-containing compounds are present in the earth's atmosphere as the result of emissions from natural and anthropogenic sources. Their oxidation in the atmosphere, initiated by such oxidants as OH, ozone, and nitrate radicals, leads to potentially harmful secondary pollutants such as ozone, carbonyl species, organic acids and aerosols. Ethers and esters are two classes of compounds that contribute to the complex array of organic compounds found in anthropogenically-influenced air. Additional ester is present as a result of the oxidation of the ethers. In this paper, the oxidation of diethyl ether and its two main oxidation products, ethyl formate and ethyl acetate, are studied over ranges of temperature, oxygen partial pressure, and NOx concentration, using an environmental chamber / FTIR absorption technique. Major end-products (the esters from diethyl ether; organic acids and anhydrides from the esters) are quantified, and these data are interpreted in terms of the chemistry of the various alkoxy and peroxy radicals generated. Emphasis is placed on the effects of chemical activation on the behavior of the alkoxy radicals, as well as on a novel peroxy radical rearrangement that may contribute to the observed products of ether oxidation under some conditions. Finally, the data are used, in conjunction with data on similar species, to provide a general representation of ether and ester oxidation in the atmosphere.

  12. Toluene decomposition performance and NOx by-product formation during a DBD-catalyst process.

    PubMed

    Guo, Yufang; Liao, Xiaobin; Fu, Mingli; Huang, Haibao; Ye, Daiqi

    2015-02-01

    Characteristics of toluene decomposition and formation of nitrogen oxide (NOx) by-products were investigated in a dielectric barrier discharge (DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide (MnOx), iron oxide (FeOx), cobalt oxide (CoOx) and copper oxide (CuO), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density (SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the CuO catalyst showed the best performance in NOx suppression. The MnOx catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression.

  13. Bioanalytical and chemical assessment of the disinfection by-product formation potential: role of organic matter.

    PubMed

    Farré, Maria José; Day, Sophie; Neale, Peta A; Stalter, Daniel; Tang, Janet Y M; Escher, Beate I

    2013-09-15

    Disinfection by-products (DBP) formed from natural organic matter and disinfectants like chlorine and chloramine may cause adverse health effects. Here, we evaluate how the quantity and quality of natural organic matter and other precursors influence the formation of DBPs during chlorination and chloramination using a comprehensive approach including chemical analysis of regulated and emerging DBPs, total organic halogen quantification, organic matter characterisation and bioanalytical tools. In vitro bioassays allow us to assess the hazard potential of DBPs early in the chain of cellular events, when the DBPs react with their molecular target(s) and activate stress response and defence mechanisms. Given the reactive properties of known DBPs, a suite of bioassays targeting reactive modes of toxic action including genotoxicity and sensitive early warning endpoints such as protein damage and oxidative stress were evaluated in addition to cytotoxicity. Coagulated surface water was collected from three different drinking water treatment plants, along with reverse osmosis permeate from a desalination plant, and DBP formation potential was assessed after chlorination and chloramination. While effects were low or below the limit of detection before disinfection, the observed effects and DBP levels increased after disinfection and were generally higher after chlorination than after chloramination, indicating that chlorination forms higher concentrations of DBPs or more potent DBPs in the studied waters. Bacterial cytotoxicity, assessed using the bioluminescence inhibition assay, and induction of the oxidative stress response were the most sensitive endpoints, followed by genotoxicity. Source waters with higher dissolved organic carbon levels induced increased DBP formation and caused greater effects in the endpoints related to DNA damage repair, glutathione conjugation/protein damage and the Nrf2 oxidative stress response pathway after disinfection. Fractionation studies

  14. Rapid process for producing transparent, monolithic porous glass

    DOEpatents

    Coronado, Paul R.

    2006-02-14

    A process for making transparent porous glass monoliths from gels. The glass is produced much faster and in much larger sizes than present technology for making porous glass. The process reduces the cost of making large porous glass monoliths because: 1) the process does not require solvent exchange nor additives to the gel to increase the drying rates, 2) only moderate temperatures and pressures are used so relatively inexpensive equipment is needed, an 3) net-shape glass monoliths are possible using this process. The process depends on the use of temperature to control the partial pressure of the gel solvent in a closed vessel, resulting in controlled shrinking during drying.

  15. Assessment of the formation of inorganic oxidation by-products during the electrocatalytic treatment of ammonium from landfill leachates.

    PubMed

    Pérez, G; Saiz, J; Ibañez, R; Urtiaga, A M; Ortiz, I

    2012-05-15

    This work investigates the formation of oxidation by-products during the electrochemical removal of ammonium using BDD electrodes from wastewaters containing chlorides. The influence of the initial chloride concentration has been experimentally analyzed first, working with model solutions with variable ammonium concentration and second, with municipal landfill leachates. Two different levels of chloride concentration were studied, i) low chloride concentrations ranging between 0 and 2000 mg/L and, ii) high chloride concentrations ranging between 5000 and 20,000 mg/L. Ammonium removal took place mainly via indirect oxidation leading to the formation of nitrogen gas and nitrate as the main oxidation products; at high chloride concentration the formation of nitrogen gas and the rate of ammonium removal were both favored. However, chloride was also oxidized during the electrochemical treatment leading to the formation of free chlorine responsible of the ammonium oxidation, together with undesirable products such as chloramines, chlorate and perchlorate. Chloramines appeared during the treatment but they reached a maximum and then started decreasing, being totally removed when high chloride concentrations were used. With regard to the formation of chlorate and perchlorate once again the concentration of chloride exerted a strong influence on the formation kinetics of the oxidation by-products and whereas at low chloride concentrations, chlorate appeared like an intermediate compound leading to the formation of perchlorate, at high chloride concentrations chlorate formation was delayed significantly and perchlorate was not detected during the experimental time. Thus this work contributes first to the knowledge of the potential hazards of applying the electro-oxidation technology as an environmental technology to deal with ammonium oxidation under the presence of chloride and second it reports efficient conditions that minimize or even avoid the formation of undesirable

  16. Impact of antioxidants on the formation of volatile secondary lipid oxidation products in oil-in-water emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food emulsions are particularly susceptible to lipid oxidation, which leads to the formation of off-flavors and odors, and ultimately, shorter product shelf lives. Here we examine antioxidants for use in emulsions from a variety of different sources, including natural product extracts as well as rat...

  17. Metolachlor and alachlor breakdown product formation patterns in aquatic field mesocosms

    USGS Publications Warehouse

    Graham, W.H.; Graham, D.W.; DeNoyelles, F.; Smith, V.H.; Larive, C.K.; Thurman, E.M.

    1999-01-01

    The transformation of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)- N-(2-methoxy-1-methyl)ethyl)acetamide] and alachlor [2-chloro-N-(2,6- diethylphenyl)-N-methoxymethyl)acetamide] in aquatic systems was investigated using outdoor tank mesocosms. Metolachlor and alachlor levels and their ethane sulfonic acid (ESA) and oxanillic acid breakdown products were monitored over time under five experimental treatments (each in quadruplicate). Background water conditions were identical in all treatments with each treatment differing based on the level and type(s) of herbicide present. Treatments included a noherbicide control, 10 ??g/L metolachlor, 25 ??g/L metolachlor, 25 ??g/L alachlor, and 25 ??g/L alachlor plus 25 ??g/L metolachlor in combination. The experiment was initiated by adding herbicide(s) to the units to the target concentrations; herbicide and breakdown product levels and other chemical parameters were then monitored for 85 days. In general, metolachlor half-lives were longer than alachlor half-lives under all treatments, although the differences were not statistically significant. Metolachlor half-lives (??95% confidence limits) ranged from 33.0 d (??14.1 d) to 46.2 d (??40.0 d), whereas alachlor half- lives ranged from 18.7 d (??3.5 d) to 21.0 d (??6.5 d) for different treatments. Formation patterns of ESA were similar in all treatments, whereas oxanillic acid formation differed for the two herbicides. Alachlor oxanillic acid was produced in larger quantities than metolachlor oxanillic acid and either ESA under equivalent conditions. Our results suggest that the transformation pathways for alachlor and metolachlor in aquatic systems are similar and resemble the acetochlor pathway in soils proposed by Feng (Pestic. Biochem. Physiol. 1991, 34, 136); however, the oxanillic acid branch of the pathway is favored for alachlor as compared with metolachlor.The transformation of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N- (2-methoxy-1-methylethy

  18. Contribution of citrulline to the formation of ethyl carbamate during Chinese rice wine production.

    PubMed

    Wang, Peihong; Sun, Junyong; Li, Xiaomin; Wu, Dianhui; Li, Tong; Lu, Jian; Chen, Jian; Xie, Guangfa

    2014-04-01

    Ethyl carbamate is a well-known carcinogen and widely occurs in Chinese rice wine. To provide more clues to minimise ethyl carbamate accumulation, the levels of possible precursors of ethyl carbamate in Chinese rice wine were investigated by HPLC. Studies of the possible precursors of ethyl carbamate in Chinese raw rice wine with various additives and treatments indicated that significant amounts of urea can account for ethyl carbamate formation. It was also recognised that citrulline is another important precursor that significantly affects ethyl carbamate production during the boiling procedure used in the Chinese rice wine manufacturing process. Besides urea and citrulline, arginine was also found to be an indirect ethyl carbamate precursor due to its ability to form urea and citrulline by microorganism metabolism.

  19. Interleukin 18 inhibits osteoclast formation via T cell production of granulocyte macrophage colony-stimulating factor.

    PubMed Central

    Horwood, N J; Udagawa, N; Elliott, J; Grail, D; Okamura, H; Kurimoto, M; Dunn, A R; Martin, T; Gillespie, M T

    1998-01-01

    IL-18 inhibits osteoclast (OCL) formation in vitro independent of IFN-gamma production, and this was abolished by the addition of neutralizing antibodies to GM-CSF. We now establish that IL-18 was unable to inhibit OCL formation in cocultures using GM-CSF-deficient mice (GM-CSF -/-). Reciprocal cocultures using either wild-type osteoblasts with GM-CSF -/- spleen cells or GM-CSF -/- osteoblasts with wild-type spleen cells were examined. Wild-type spleen cells were required to elicit a response to IL-18 indicating that cells of splenic origin were the IL-18 target. As T cells comprise a large proportion of the spleen cell population, the role of T cells in osteoclastogenesis was examined. Total T cells were removed and repleted in various combinations. Addition of wild-type T cells to a GM-CSF -/- coculture restored IL-18 inhibition of osteoclastogenesis. Major subsets of T cells, CD4+ and CD8+, were also individually depleted. Addition of either CD4+ or CD8+ wild-type T cells restored IL-18 action in a GM-CSF -/- background, while IL-18 was ineffective when either CD4+ or CD8+ GM-CSF -/- T cells were added to a wild-type coculture. These results highlight the involvement of T cells in IL-18-induced OCL inhibition and provide evidence for a new OCL inhibitory pathway whereby IL-18 inhibits OCL formation due to action upon T cells promoting the release of GM-CSF, which in turn acts upon OCL precursors. PMID:9449693

  20. A monolithic bolometer array suitable for FIRST

    NASA Technical Reports Server (NTRS)

    Bock, J. J.; LeDuc, H. G.; Lange, A. E.; Zmuidzinas, J.

    1997-01-01

    The development of arrays of infrared bolometers that are suitable for use in the Far Infrared and Submillimeter Telescope (FIRST) mission is reported. The array architecture is based on the silicon nitride micromesh bolometer currently baselined for use in the case of the Planck mission. This architecture allows each pixel to be efficiently coupled to one or both polarizations and to one or more spatial models of radiation. Micromesh structures are currently being developed, coupled with transistor-edge sensors and read out by a SQUID amplifier. If these devices are successful, then the relatively large cooling power available at 300 mK may enable a SQUID-based multiplexer to be integrated on the same wafer as the array, creating a monolithic, fully multiplexed, 2D array with relatively few connections to the sub-Kelvin stage.

  1. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K.; Wei, G.; Yu, P.C.

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  2. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. . Electro-Optics Technology Center); Wei, G. ); Yu, P.C. )

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  3. Solid oxide fuel cell having monolithic core

    NASA Astrophysics Data System (ADS)

    Ackerman, J. P.; Young, J. E.

    1983-10-01

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. The core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces have only the anode material or only the cathode material exposed. Each layer of the electrolyte and interconnect materials 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is 0.002 to 0.05 cm thick.

  4. A study of subterahertz HEMT monolithic oscillators

    NASA Technical Reports Server (NTRS)

    Kwon, Youngwoo; Pavlidis, Dimitris

    1992-01-01

    A detailed study of monolithic InP-based HEMT oscillators for subterahertz operation is presented. InAlAs/InGaAs HEMT's have been optimized for high frequency operation and showed very high maximum oscillation frequencies (f(sub max)) of 310 GHz using offset self-aligned gamma-gate technology. Power characteristics of HEMT oscillators are reported. An oscillation power of more than 10 mW was evaluated by large-signal analysis at 320 GHz using HEMT's with f(sub max) = 450 GHz, V(sub br) = 10 V and a gate width (W(sub g)) of 8 x 22.5 microns. Oscillator topology studies showed that complex feedback schemes such as dual and active feedback enhance the negative resistance. Push-push oscillator designs based on harmonic signal generation can finally be used to overcome the frequency barrier imposed by f(sub max).

  5. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

  6. Monolithic cascade-type solar cells

    NASA Technical Reports Server (NTRS)

    Yamamoto, S.; Shibukawa, A.; Yamaguchi, M.

    1985-01-01

    Solar cells consist of a semiconductor base, a bottom cell with a band-gap energy of E1, and a top cell with a band-gap energy of E2, and 0.96 E1 1.36 eV and (0.80 E + 0.77) eV E2 (0.80 E1 + 0.92) eV. A monolithic cascade-type solar cell was prepared with an n(+)-type GaAs base, a GaInAs bottom solar cell, and a GaAiInAs top solar cell. The surface of the cell is coated with a SiO antireflection film. The efficiency of the cell is 32%.

  7. Monolithic fuel injector and related manufacturing method

    DOEpatents

    Ziminsky, Willy Steve [Greenville, SC; Johnson, Thomas Edward [Greenville, SC; Lacy, Benjamin [Greenville, SC; York, William David [Greenville, SC; Stevenson, Christian Xavier [Greenville, SC

    2012-05-22

    A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

  8. Development of 20 GHz monolithic transmit modules

    NASA Technical Reports Server (NTRS)

    Higgins, J. A.

    1988-01-01

    The history of the development of a transmit module for the band 17.7 to 20.2 GHz is presented. The module was to monolithically combine, on one chip, five bits of phase shift, a buffer amplifier and a power amplifier to produce 200 mW to the antenna element. The approach taken was MESFET ion implanted device technology. A common pinch-off voltage was decided upon for each application. The beginning of the total integration phases revealed hitherto unencountered hazards of large microwave circuit integration which were successfully overcome. Yield and customer considerations finally led to two separate chips, one containing the power amplifiers and the other containing the complete five bit phase shifter.

  9. LSST primary/tertiary monolithic mirror

    NASA Astrophysics Data System (ADS)

    Sebag, J.; Gressler, W.; Liang, M.; Neill, D.; Araujo-Hauck, C.; Andrew, J.; Angeli, G.; Cho, M.; Claver, C.; Daruich, F.; Gessner, C.; Hileman, E.; Krabbendam, V.; Muller, G.; Poczulp, G.; Repp, R.; Wiecha, O.; Xin, B.; Kenagy, K.; Martin, H. M.; Tuell, M. T.; West, S. C.

    2016-08-01

    At the core of the Large Synoptic Survey Telescope (LSST) three-mirror optical design is the primary/tertiary (M1M3) mirror that combines these two large mirrors onto one monolithic substrate. The M1M3 mirror was spin cast and polished at the Steward Observatory Mirror Lab at The University of Arizona (formerly SOML, now the Richard F. Caris Mirror Lab at the University of Arizona (RFCML)). Final acceptance of the mirror occurred during the year 2015 and the mirror is now in storage while the mirror cell assembly is being fabricated. The M1M3 mirror will be tested at RFCML after integration with its mirror cell before being shipped to Chile.

  10. Monolithic geometric anti-spring blades

    NASA Astrophysics Data System (ADS)

    Cella, G.; Sannibale, V.; DeSalvo, R.; Márka, S.; Takamori, A.

    2005-03-01

    In this article we investigate the principle and properties of a vertical passive seismic noise attenuator conceived for ground based gravitational wave interferometers. This mechanical attenuator based on a particular geometry of cantilever blades called monolithic geometric anti springs (MGAS) permits the design of mechanical harmonic oscillators with very low resonant frequency (below 10 mHz). Here we address the theoretical description of the mechanical device, focusing on the most important quantities for the low-frequency regime, on the distribution of internal stresses, and on the thermal stability. In order to obtain physical insight of the attenuator peculiarities, we devise some simplified models, rather than use the brute force of finite element analysis. Those models have been used to optimize the design of a seismic attenuation system prototype for LIGO advanced configurations and for the next generation of the TAMA interferometer.

  11. Chlorination and monochloramination of 3-aminophenol: kinetics and formation of first by-products.

    PubMed

    Abou Mehrez, O; Dossier-Berne, F; Legube, B

    2015-01-01

    Aminophenols (AP) are synthetic intermediates in pharmaceutical, photographic and chemical dye industry. They can be released into the environment from wastewater and can react during water treatment processes. Therefore, it was interesting to study the oxidation of AP with chlorine and monochloramine in aqueous solution. In particular, the chlorination and monochloramination of 3-aminophenol (3AP) were investigated, and the formation of first by-products and kinetic rates were determined. The chlorination rate was 3.6 × 10(5) times greater than the monochloramination rate at pH 8.6. Two reaction pathways can explain the variation of the monochloramination apparent rate constant with pH. The first one was an electrophilic substitution of Cl(+) on the aromatic ring of the non-ionized 3AP, leading to the formation of chloroaminophenol, with an individual rate constant of 6.7 × 10(2) M(-1) h(-1). The second reaction pathway was a monochloramine attack on the amino group of 3AP catalyzed at acidic pH with an individual rate constant of 9.2 × 10(9) × M(-2) × h(-1).

  12. Carbonaceous and nitrogenous disinfection by-product formation from algal organic matter.

    PubMed

    Goslan, Emma H; Seigle, Céline; Purcell, Diane; Henderson, Rita; Parsons, Simon A; Jefferson, Bruce; Judd, Simon J

    2017-03-01

    Seasonal algal blooms in drinking water sources release intracellular and extracellular algal organic matter (AOM) in significant concentrations into the water. This organic matter provides precursors for disinfection by-products (DBPs) formed when the water is subsequently chlorinated at the final disinfection stage of the potable water treatment process. This paper presents results of AOM characterisation from five algal species (three cyanobacteria, one diatom and one green) alongside the measurement of the DBP formation potential from the AOM of six algal species (an additional diatom). The character was explored in terms of hydrophilicity, charge and protein and carbohydrate content. 18 DBPs were measured following chlorination of the AOM samples: the four trihalomethanes (THMs), nine haloacetic acids (HAAs), four haloacetonitriles (HANs) and one halonitromethane (HNM). The AOM was found to be mainly hydrophilic (52 and 81%) in nature. Yields of up to 92.4 μg mg(-1) C carbonaceous DBPs were measured, with few consistent trends between DBP formation propensity and either the specific ultraviolet absorbance (SUVA) or the chemical characteristics. The AOM from diatomaceous algae formed significant amounts of nitrogenous DBPs (up to 1.7 μg mg(-1) C). The weak trends in DBPFP may be attributable to the hydrophilic nature of AOM, which also makes it more challenging to remove by conventional water treatment processes.

  13. Building Bridges: Biocatalytic C–C-Bond Formation toward Multifunctional Products

    PubMed Central

    2016-01-01

    Carbon–carbon bond formation is the key reaction for organic synthesis to construct the carbon framework of organic molecules. The review gives a selection of biocatalytic C–C-bond-forming reactions which have been investigated during the last 5 years and which have already been proven to be applicable for organic synthesis. In most cases, the reactions lead to products functionalized at the site of C–C-bond formation (e.g., α-hydroxy ketones, aminoalcohols, diols, 1,4-diketones, etc.) or allow to decorate aromatic and heteroaromatic molecules. Furthermore, examples for cyclization of (non)natural precursors leading to saturated carbocycles are given as well as the stereoselective cyclopropanation of olefins affording cyclopropanes. Although many tools are already available, recent research also makes it clear that nature provides an even broader set of enzymes to perform specific C–C coupling reactions. The possibilities are without limit; however, a big library of variants for different types of reactions is required to have the specific enzyme for a desired specific (stereoselective) reaction at hand. PMID:27398261

  14. Control of disinfection by-product formation using ozone-based advanced oxidation processes.

    PubMed

    Chen, Kuan-Chung; Wang, Yu-Hsiang

    2012-01-01

    The effects of ozone dosage, water temperature and catalyst addition in an ozonation-fluidized bed reactor (O3/FBR) on treated water quality and on the control of chlorinated and ozonated disinfection by-products (DBPs) were investigated. A biofiltration column was used to evaluate its removal efficiency on biodegradable organic matter and to reduce DBP formation. The Dong-Gang River, polluted by agricultural and domestic wastewater in Pingtung, Taiwan, was used as the water source. The treated water quality in terms of dissolved organic carbon (DOC), biodegradable DOC, ultraviolet absorbance at 254 nm (UV254) and specific UV absorbance (SUVA) improved with increasing ozone and catalyst dosages. Catalytic ozonation was more effective than ozonation alone at reducing the formation of DBPs at a given dosage. Experimental results show that water temperature had little effect on the treated water quality with the O3/FBR system used in this study (p > 0.05). The combination of O3/FBR and the biofiltration process effectively decreased the amount ofDBP precursors. The concentration of total trihalomethanes (TTHMs) was less than the maximum contaminant level (MCL) requirement, which is 80 microg/L, for all treated waters and the concentration of five haloacetic acids (HAA5) fell below 60 microg/L with an ozone dosage higher than 2.5 mg/L.

  15. Building Bridges: Biocatalytic C-C-Bond Formation toward Multifunctional Products.

    PubMed

    Schmidt, Nina G; Eger, Elisabeth; Kroutil, Wolfgang

    2016-07-01

    Carbon-carbon bond formation is the key reaction for organic synthesis to construct the carbon framework of organic molecules. The review gives a selection of biocatalytic C-C-bond-forming reactions which have been investigated during the last 5 years and which have already been proven to be applicable for organic synthesis. In most cases, the reactions lead to products functionalized at the site of C-C-bond formation (e.g., α-hydroxy ketones, aminoalcohols, diols, 1,4-diketones, etc.) or allow to decorate aromatic and heteroaromatic molecules. Furthermore, examples for cyclization of (non)natural precursors leading to saturated carbocycles are given as well as the stereoselective cyclopropanation of olefins affording cyclopropanes. Although many tools are already available, recent research also makes it clear that nature provides an even broader set of enzymes to perform specific C-C coupling reactions. The possibilities are without limit; however, a big library of variants for different types of reactions is required to have the specific enzyme for a desired specific (stereoselective) reaction at hand.

  16. Exit routes from the transition state: Angular momentum constraints on the formation of products.

    PubMed

    McCaffery, Anthony J; Osborne, Mark A; Marsh, Richard J

    2005-06-16

    We have analyzed experimental data from a number of exothermic processes in which molecules in well-defined initial states are deactivated by inelastic, dissociative, or reactive collisions. Further, we analyze deactivation processes that do not occur in molecules despite their containing high levels of excitation. Significant common elements are found among these forms of deactivation. The initial step consists of transition to a product state involving minimum rotation state change (Delta j) consistent with energy conservation. Frequently, this process is near-energy-resonant. More critically, it may frequently require substantial angular momentum (AM) change. Analysis of experimental data indicates that constraints act upon on the formation of products in processes that involve release of excess energy. These constraints are associated with the magnitude of AM that must be generated for the initial transition to occur and this AM "load" increases with the amount of energy to be released. In general, the probability of generating rotational AM falls rapidly as Delta j increases, and this effectively limits the size of energy gap that may be bridged by a given reactant pair and at some point the constraint is sufficient to constitute a barrier that prevents the process from taking place. The choice of reactant species strongly affects the probability of each process that increases (i) when molecules efficiently interconvert momentum and (ii) when many product states are available in the critical near-resonant region. These factors increase the proportion of initial trajectories that possess the energy and momentum necessary to open a "product" channel. Evidence is presented showing that AM load-reduction strategies lead to marked enhancement of rates of collision-induced processes, suggesting that reduction of constraints in the exit channels from the transition state may constitute a previously unrecognized form of catalysis.

  17. Catalysis by methyl-coenzyme M reductase: a theoretical study for heterodisulfide product formation.

    PubMed

    Pelmenschikov, Vladimir; Siegbahn, Per E M

    2003-07-01

    Hybrid density functional theory has been used to investigate the catalytic mechanism of methyl-coenzyme M reductase (MCR), an essential enzyme in methanogenesis. In a previous study of methane formation, a scheme was suggested involving oxidation of Ni(I) in the starting square-planar coordination to the high-spin Ni(II) form in the CoM-S-Ni(II)F(430) octahedral intermediate. The methyl radical, concomitantly released by methyl-coenzyme M (CoM), is rapidly quenched by hydrogen atom transfer from the coenzyme B (CoB) thiol group, yielding methane as the first product of the reaction. The present investigation primarily concerns the second and final step of the reaction: oxidation of CoB and CoM to the CoB-S-S-CoM heterodisulfide product and reduction of nickel back to the Ni(I) square-planar form. The activation energy for the second step is found to be around 10 kcal/mol, implying that the first step of methane formation with an activation energy of 20 kcal/mol should be rate-limiting. An oxygen of the Gln147 residue, occupying the rear axial position in the oxidized Ni(II) state, is shown to stabilize the intermediate by 6 kcal/mol, thereby slightly decreasing the barrier for the preceding rate-limiting transition state. The mechanism suggested is discussed in the context of available experimental data. An analysis of the flexibility of the F(430) cofactor during the reaction cycle is also given.

  18. Formation of nitrogenous disinfection by-products in 10 chlorinated and chloraminated drinking water supply systems.

    PubMed

    Liew, Deborah; Linge, Kathryn L; Joll, Cynthia A

    2016-09-01

    The presence of nitrogenous disinfection by-products (N-DBPs) in drinking water supplies is a public health concern, particularly since some N-DBPs have been reported to be more toxic than the regulated trihalomethanes and haloacetic acids. In this paper, a comprehensive evaluation of the presence of N-DBPs in 10 drinking water supply systems in Western Australia is presented. A suite of 28 N-DBPs, including N-nitrosamines, haloacetonitriles (HANs), haloacetamides (HAAms) and halonitromethanes (HNMs), were measured and evaluated for relationships with bulk parameters in the waters before disinfection. A number of N-DBPs were frequently detected in disinfected waters, although at generally low concentrations (<10 ng/L for N-nitrosamines and <10 μg/L for other N-DBPs) and below health guideline values where they exist. While there were no clear relationships between N-DBP formation and organic nitrogen in the pre-disinfection water, N-DBP concentrations were significantly correlated with dissolved organic carbon (DOC) and ammonia, and these, in addition to high bromide in one of the waters, led to elevated concentrations of brominated HANs (26.6 μg/L of dibromoacetonitrile). There were significant differences in the occurrence of all classes of N-DBPs between chlorinated and chloraminated waters, except for HNMs, which were detected at relatively low concentrations in both water types. Trends observed in one large distribution system suggest that N-DBPs can continue to form or degrade within distribution systems, and redosing of disinfectant may cause further by-product formation.

  19. Synthesis of silver nanoparticles confined in hierarchically porous monolithic silica: a new function in aromatic hydrocarbon separations.

    PubMed

    Zhu, Yang; Morisato, Kei; Li, Wenyan; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2013-03-01

    Silver nanoparticles (Ag NPs) have been homogeneously introduced into hierarchically porous monolithic silica columns with well-defined macropores and SBA-15-type hexagonally ordered mesopores by using ethanol as the mild reductant. Within the cylindrical silica mesopores treated with aminopropyl groups as the host, monocrystalline Ag NPs and nanorods are obtained after being treated in silver nitrate/ethanol solution at room temperature for different durations of reducing time. The loading of Ag NPs in the monolith can be increased to 33 wt % by the repetitive treatment, which also led to the formation of polycrystalline Ag nanorods in the mesopores. Although the bare silica column cannot separate aromatic hydrocarbons, good separation of those molecules by noncharged Ag NPs confined in the porous structure of the monolith has been for the first time demonstrated with the Ag NP-embedded silica column. The NP-embedded monolithic silica would be a powerful separation tool for hydrocarbons with different number, position, and configuration of unsaturated bonds.

  20. IRRADIATION PERFORMANCE OF U-Mo MONOLITHIC FUEL

    SciTech Connect

    M.K. Meyer; J. Gan; J.-F. Jue; D.D. Keiser; E. Perez; A. Robinson; D.M. Wachs; N. Woolstenhulme; G.L. Hofman; Y.-S. Kim

    2014-04-01

    High-performance research reactors require fuel that operates at high specific power to high fission density, but at relatively low temperatures. Research reactor fuels are designed for efficient heat rejection, and are composed of assemblies of thin-plates clad in aluminum alloy. The development of low-enriched fuels to replace high-enriched fuels for these reactors requires a substantially increased uranium density in the fuel to offset the decrease in enrichment. Very few fuel phases have been identified that have the required combination of very-high uranium density and stable fuel behavior at high burnup. UMo alloys represent the best known tradeoff in these properties. Testing of aluminum matrix U-Mo aluminum matrix dispersion fuel revealed a pattern of breakaway swelling behavior at intermediate burnup, related to the formation of a molybdenum stabilized high aluminum intermetallic phase that forms during irradiation. In the case of monolithic fuel, this issue was addressed by eliminating, as much as possible, the interfacial area between U-Mo and aluminum. Based on scoping irradiation test data, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development. Developmental testing of this fuel system indicates that it meets core criteria for fuel qualification, including stable and predictable swelling behavior, mechanical integrity to high burnup, and geometric stability. In addition, the fuel exhibits robust behavior during power-cooling mismatch events under irradiation at high power.

  1. The pivotal role of chelation as a stereochemical control element in non-Evans anti aldol product formation.

    PubMed

    Shinisha, C B; Sunoj, Raghavan B

    2010-06-18

    The origin of stereoselective formation of Evans syn and non-Evans anti aldol products in the reaction between titanium enolate derived from N-succinyloxazolidinone and benzaldehyde is established by using transition-state modeling. The chelated transition-state model is found to hold the key to otherwise less likely non-Evans anti aldol product, whereas the nonchelated model offers a convincing rationalization toward Evans syn aldol product. The computed results are in agreement with the reported experimental observations.

  2. Monolithically Integrated SiGe/Si PIN-HBT Front-End Transimpedance Photoreceivers

    NASA Technical Reports Server (NTRS)

    Rieh, J.-S.; Qasaimeh, O.; Klotzkin, D.; Lu, L.-H.; Katehi, L. P. B.; Yang, K.; Bhattacharya, P.; Croke, E. T.

    1997-01-01

    The demand for monolithically integrated photoreceivers based on Si-based technology keeps increasing as low cost and high reliability products are required for the expanding commercial market. Higher speed and wider operating frequency range are expected when SiGe/Si heterojunction is introduced to the circuit design. In this paper, a monolithic SiGe/Si PIN-HBT front-end transimpedance photoreceiver is demonstrated for the first time. For this purpose, mesa-type SiGe/Si PIN-HBT technology was developed. Fabricated HBTs exhibit f(sub max) of 34 GHz with DC gain of 25. SiGe/Si PIN photodiodes, which share base and collector layers of HBTs, demonstrate responsivity of 0.3 A/W at lambda=850 nm and bandwidth of 450 MHz. Based on these devices, single- and dual-feedback transimpedance amplifiers were fabricated and they exhibited the bandwidth of 3.2 GHz and 3.3 GHz with the transimpedance gain of 45.2 dB(Omega) and 47.4 dB(Omega) respectively. Monolithically integrated single-feedback PIN-HBT photoreceivers were implemented and the bandwidth was measured to be approx. 0.5 GHz, which is limited by the bandwidth of PIN photodiodes.

  3. Fabrication and testing of U-7Mo monolithic plate fuel with Zircaloy cladding

    NASA Astrophysics Data System (ADS)

    Pasqualini, E. E.; Robinson, A. B.; Porter, D. L.; Wachs, D. M.; Finlay, M. R.

    2016-10-01

    Nuclear fuel designs are being developed to replace highly enriched fuel used in research and test reactors with fuels of low enrichment. In the most challenging cases, U-(7-10 wt%)Mo monolithic plate fuels are proposed. One of the considered designs includes aluminum-alloy cladding, which provides some challenges in fabrication and fuel/cladding interaction during service. Zircaloy cladding, specifically Zry-4, was investigated as an alternative cladding, and development of a fabrication method was performed by researchers with the Comisión Nacionalde Energia Atómica (CNEA) in Argentina, resulting in test fuel plates (Zry-4 clad U-7Mo) which were subsequently tested in the Advanced Test Reactor in Idaho. Because Zry-4 and U-(7-10)Mo have similar high-temperature mechanical properties, fabrication was simplified in that the fuel foil and cladding could be co-rolled and bonded. The challenge was to prevent a thermal-expansion mismatch, which could destroy the fuel/cladding bond before complete bonding was achieved; the solution was to prevent the composites from cooling significantly during or between roll passes. The final product performed very well in-reactor, showing good bonding, very little fuel/cladding interaction-either from fabrication or in-reactor testing-and little swelling, especially no detectable heterogeneous bubble formation at the fuel/cladding interface tested to a fission density of up to 2.7E+21 (average) fissions/cm3, 3.8E+21 (peak).

  4. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    SciTech Connect

    Mark J. Rigali

    2001-10-01

    Published mechanical and thermal properties data on a variety of materials was gathered, with focus on materials that have potential with respect to developing wear resistant and damage tolerant composite for mining industry applications. Preliminary core materials of interest include but are not limited to: Diamond, Tungsten Carbide and Cemented Tungsten Carbides, Carbides of Boron, Silicon, Titanium and Aluminum, Diboride of Titanium and Aluminum, Nitrides of Aluminum, Silicon, Titanium, and Boron, Aluminum Oxide, Tungsten, Titanium, Iron, Cobalt and Metal Alloys. Preliminary boundary materials of interest include but are not limited to: W metal, WC-Co, W-Co, WFeNi, and Mo metal and alloys. Several FM test coupons were fabricated with various compositions using the above listed materials. These coupons were consolidated to varying degrees by uniaxial hot pressing, then cut and ground to expose the FM cell structure. One promising system, WC-Co core and WFeNi boundary, was consolidated to 97% of theoretical density, and demonstrates excellent hardness. Data on standard mechanical tests was gathered, and tests will begin on the consolidated test coupons during the upcoming reporting period. The program statements of work for ACR Inc. and its subcontractors, as well as the final contract negotiations, were finalized during the current reporting period. The program start date was February 22nd, 2001. In addition to the current subcontractors, Kennametal Inc., a major manufacturer of cutting tools and wear resistant tooling for the mining industry, expressed considerable interest in ACR's Fibrous Monolith composites for both machine and mining applications. At the request of Kennametal, ARC Inc fabricated and delivered several Fibrous Monolith coupons and components for testing and evaluation in the mining and machine tool applications. Additional samples of Diamond/Tungsten Carbide-6%Cobalt Fibrous Monolith were fabricated and delivered for testing Kennametal's Rapid

  5. Formation of Sclerotia and Production of Indoloterpenes by Aspergillus niger and Other Species in Section Nigri

    PubMed Central

    Frisvad, Jens C.; Petersen, Lene M.; Lyhne, E. Kirstine; Larsen, Thomas O.

    2014-01-01

    Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time. PMID:24736731

  6. Formation of sclerotia and production of indoloterpenes by Aspergillus niger and other species in section Nigri.

    PubMed

    Frisvad, Jens C; Petersen, Lene M; Lyhne, E Kirstine; Larsen, Thomas O

    2014-01-01

    Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time.

  7. 25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM). NOTE GANTRY CRANES - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  8. 26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  9. 10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING NORTH. August 1934 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 16, Upper Mississippi River, Muscatine, Muscatine County, IA

  10. 53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 1722, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 17-22, INTERMEDIATE WALL, LOOKING NORTH Photograph No. 12840. September 10, 1948 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  11. 62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 321, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 32-1, LOOKING WEST Photograph No. 8571. October 24, 1949 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  12. 31. SPILLWAY CHANNEL WALLS REINF DETAILS; MONOLITHS E21 AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. SPILLWAY CHANNEL WALLS REINF - DETAILS; MONOLITHS E-21 AND W-21. Sheet S-45, May, 1940. File no. 342/58. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  13. 27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END OF WEST MAIN LOCK WALL, LOOKiNG SOUTHEAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  14. Hierarchical Porous Polystyrene Monoliths from PolyHIPE.

    PubMed

    Yang, Xinjia; Tan, Liangxiao; Xia, Lingling; Wood, Colin D; Tan, Bien

    2015-09-01

    Hierarchical porous polystyrene monoliths (HCP-PolyHIPE) are obtained by hypercrosslinking poly(styrene-divinylbenzene) monoliths prepared by polymerization of high internal phase emulsions (PolyHIPEs). The hypercrosslinking is achieved using an approach known as knitting which employs formaldehyde dimethyl acetal (FDA) as an external crosslinker. Scanning electron microscopy (SEM) confirms that the macroporous structure in the original monolith is retained during the knitting process. By increasing the amount of divinylbenzene (DVB) in PolyHIPE, the BET surface area and pore volume of the HCP-PolyHIPE decrease, while the micropore size increases. BET surface areas of 196-595 m(2) g(-1) are obtained. The presence of micropores, mesopores, and macropores is confirmed from the pore size distribution. With a hierarchical porous structure, the monoliths reveal comparable gas sorption properties and potential applications in oil spill clean-up.

  15. The features of ceramic materials structure formation when using hard-melting wastes of thermal power stations in charge stock

    NASA Astrophysics Data System (ADS)

    Skripnikova, Nelli; Yuriev, Ivan; Lutsenko, Alexander; Litvinova, Viktoriya

    2016-01-01

    The paper presents the analysis of aluminum silicate waste generated by thermal power station of the city of Seversk, Tomsk region, Russia. The chemical compositions of aluminum silicate waste are detected and the efficient mixture compositions with the addition of aluminum silicate waste are suggested herein. Ceramic brick structure formation is studied in this paper using X-ray phase and SEM analyses. It is identified that the formed vitreous phase facilitates such strengthening structural modifications as sintering out of pores and shrinkage of unmelted aluminum silicate particles with the following formation of a monolithic product.

  16. Geochemical study of products associated with spontaneous oxidation of coal in the Cerro Pelado Formation, Venezuela

    NASA Astrophysics Data System (ADS)

    Martínez, M.; Márquez, G.; Alejandre, F. J.; Del Río, J. J.; Hurtado, A.

    2009-02-01

    The aim of this research work is a geochemical, mineralogical, and textural characterization of spontaneously smouldered coal-derived products in northwestern Venezuela (Cerro Pelado Formation, some 10 km from Pedregal city). Several solid samples were collected from this formation, six of unweathering coal, an other six of resulting unmelted rocks forming on a surface coal bed, and the last four of mineralizations found accumulating around gas vents. The fresh coal and the unmelted material were analysed by scanning electron microscopy, X-ray diffraction, and proximate techniques. Products such as magnetite and chabazite-K were identified in the alteration rocks. Likewise, both materials were also studied in order to determine the mobilization of 17 elements into the environment; such elements were analysed through inductively coupled plasma atomic emission spectroscopy on extracts obtained by a sequential extraction method: each sample was firstly extracted with MilliQ water and then the resultant residue was washed. This and the subsequently resulting residues are extracted according to the mentioned procedure by using, respectively, ammonium acetate, chlorhydric acid, peroxide and chlorhydric acid, nitric acid and fluorhydric acid, and nitric acid. The studied elements are classified as highly mobile (Na, Ni, ...), nearly immobile (Ti, P) and partially mobile (Mg, Fe, K, ...). In regards to mineralizations around fumaroles associated with smoldering coal seams, Fourier-transform infrared spectroscopy and X-ray diffraction analyses have revealed the presence of salammoniac, mascagnite and other solid combustion compounds formed by reaction of gas emitted from coal oxidation, in addition to previously non-reported sulfur-rich by-products associated with gas fissures, particularly ammonium thiosulfate, a phase first obtained only synthetically in the laboratory. Another objective of the research was to collect and analyse gases escaping from surficial vents

  17. Monolithic electronics for nuclear and high-energy physics experiments

    SciTech Connect

    Young, G.R.

    1994-12-31

    Electronic instrumentation for large fixed-target and collider experiments is rapidly moving to the use of highly integrated electronics wherever it is cost effective. This trend is aided by the development of circuit building blocks useful for nuclear and high-energy physics instrumentation and has accelerated recently with the development of monolithic silicon chips with multiple functions on one substrate. Examples of recent developments are given, together with remarks on the rationale for use of monolithic electronics and economic considerations.

  18. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    SciTech Connect

    Serne, R. Jeffrey; Westsik, Joseph H.; Williams, Benjamin D.; Jung, H. B.; Wang, Guohui

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  19. Beta-carotene degradation products - formation, toxicity and prevention of toxicity.

    PubMed

    Siems, Werner; Salerno, Costantino; Crifò, Carlo; Sommerburg, Olaf; Wiswedel, Ingrid

    2009-01-01

    Carotenoids are widely used as important micronutrients in food. Furthermore, carotenoid supplementation has been used in the treatment of diseases associated with oxidative stress such as various types of cancer, inflammatory diseases or cystic fibrosis. However, in some clinical studies harmful effects have been observed, e.g. a higher incidence of lung cancer in individuals exposed to extraordinary oxidative stress. The causal mechanisms of harmful effects are still unclear. Carotenoid breakdown products (CBPs) including highly reactive aldehydes and epoxides are formed during oxidative attacks in the course of antioxidative action. We investigated the formation of CBPs by stimulated neutrophils (and at further conditions), tested the hypothesis that CBPs may exert mitochondriotoxicity and tried to prevent toxicity in the presence of members of the antioxidative network. Stimulated neutrophils are able to degrade beta-carotene and to generate a number of CBPs. Concerning mitochondriotoxicity, we found that CBPs strongly inhibit state 3 respiration of rat liver mitochondria at concentrations between 0.5 and 20 microM. This was true for retinal, beta-ionone, and for mixtures of cleavage/breakdown products. The inhibition of mitochondrial respiration was accompanied by a reduction in protein sulfhydryl content, decreasing GSH levels and redox state, and elevated accumulation of malondialdehyde. Changes in mitochondrial membrane potential favor functional deterioration in the adenine nucleotide translocator as a sensitive target. The presence of additional antioxidants such as alpha-tocopherol, ascorbic acid, N-acetyl-cysteine or others could mitigate mitochondriotoxicity. The findings reflect a basic mechanism of increasing the risk of cancer induced by carotenoid degradation products.

  20. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: chemical characterization of the products

    NASA Astrophysics Data System (ADS)

    Grgić, Irena; Kitanovski, Zoran; Kroflič, Ana; Čusak, Alen

    2014-05-01

    One of the largest primary sources of organic aerosol in the atmosphere is biomass burning (BB) (Laskin et al. 2009); in Europe its contribution to annual mean of PM10 is between 3 and 14 % (Maenhaut et al. 2012). During the process of wood burning many different products are formed via thermal degradation of wood lignin. Hardwood burning produces mainly syringol (2,6-dimetoxyphenol) derivatives, while softwood burning exclusively guaiacol (2-methoxyphenol) and its derivatives. Taking into account physical properties of methoxyphenols only, their concentrations in atmospheric waters might be underestimated. So, their aqueous phase reactions can be an additional source of SOA, especially in regions under significant influence of wood combustion. An important class of compounds formed during physical and chemical aging of the primary BBA in the atmosphere is nitrocatechols, known as strong absorbers of UV and Vis light (Claeys et al. 2012). Very recently, methyl-nitrocatechols were proposed as suitable markers for highly oxidized secondary BBA (Iinuma et al. 2010, Kitanovski et al. 2012). In the present work, the formation of SOA through aqueous phase photooxidation and nitration of guaiacol was examined. The key objective was to chemically characterize the main low-volatility products and further to check their possible presence in the urban atmospheric aerosols. The aqueous phase reactions were performed in a thermostated reactor under simulated sunlight in the presence of H2O2 and nitrite. Guaiacol reaction products were first concentrated by solid-phase extraction (SPE) and then subjected to semi-preparative liquid chromatography.The main product compounds were fractionated and isolated as pure solids and their structure was further elucidated by using nuclear magnetic resonance spectroscopy (1H, 13C and 2D NMR) and direct infusion negative ion electro-spray ionization tandem mass spectrometry (( )ESI-MS/MS). The main photonitration products of guaiacol (4

  1. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    PubMed

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors.

  2. Capillary electrochromatography with monolithic silica column: I. Preparation of silica monoliths having surface-bound octadecyl moieties and their chromatographic characterization and applications to the separation of neutral and charged species.

    PubMed

    Allen, Darin; El Rassi, Ziad

    2003-01-01

    Monolithic silica columns with surface-bound octadecyl (C18) moieties have been prepared by a sol-gel process in 100 microm ID fused-silica capillaries for reversed-phase capillary electrochromatography of neutral and charged species. The reaction conditions for the preparation of the C18-silica monoliths were optimized for maximum surface coverage with octadecyl moieties in order to maximize retention and selectivity toward neutral and charged solutes with a sufficiently strong electroosmotic flow (> 2 mm/s) to yield rapid analysis time. Furthermore, the effect of the pore-tailoring process on the silica monoliths was performed over a wide range of treatment time with 0.010 M ammonium hydroxide solution in order to determine the optimum time and conditions that yield mesopores of narrow pore size distribution that result in high separation efficiency. Under optimum column fabrication conditions and optimum mobile phase composition and flow velocity, the average separation efficiency reached 160 000 plates/m, a value comparable to that obtained on columns packed with 3 microm C18-silica particles with the advantages of high permeability and virtually no bubble formation. The optimized monolithic C18-silica columns were evaluated for their retention properties toward neutral and charged analytes over a wide range of mobile phase compositions. A series of dimensionless retention parameters were evaluated and correlated to solute polarity and electromigration property. A dimensionless mobility modulus was introduced to describe charged solute migration and interaction behavior with the monolithic C18-silica in a counterflow regime during capillary electrochromatography (CEC )separations. The mobility moduli correlated well with the solute hydrophobic character and its charge-to-mass ratio.

  3. Estimating the CO2 sequestration potential of depleted and fractured shale formations using CH4 production rates

    NASA Astrophysics Data System (ADS)

    Clarens, A. F.; Tao, Z.

    2013-12-01

    Oil and gas production from hydraulically fractured shale formations is an abundant new source of domestically available energy for the United States. It will also result in significant CO2 emissions with important climate implications. Several studies have suggested that fractured shale formations could be used to permanently store CO2 once they are depleted of hydrocarbons. Many of the largest shale formations being developed in the United States have temperature and pressure profiles that are similar to those of saline aquifers being widely studied for geologic carbon sequestration. Here a modeling framework was developed that can be used to estimate the sequestration capacity for a shale formation based on historical CH4 production. The model is applied to those portions of the Marcellus formation found in Pennsylvania because reliable data on well production is readily available for this state. Production data from over 300 wells was compiled and used to estimate historical production and to extrapolate projected production. In shales, much of the CO2 would be sorbed to the pore and fracture surface and so this model considers sorption kinetics as well as total sorption capacity. The results suggest that shale formations could represent a significant repository for geologic carbon sequestration. The Marcellus shale in Pennsylvania alone could store between 10.4 and 18.4 Gigatonnes of CO2 between now and 2030. This would be over 50% of total annual US CO2 emissions from stationary sources. The mass transfer and sorption kinetics results indicate that CO2 injection proceeds several times faster than CH4 production. Model estimates were most sensitive to the permeability of the formation and assumptions about the ultimate ratio of adsorbed CH4 to CO2. CH4 production is a useful basis for calculating sequestration capacity because gas mass transfer out of the formation will be impacted by the same factors (e.g., temperature, pressure, and moisture content

  4. Porous monoliths for on-line sample preparation: A review.

    PubMed

    Masini, Jorge C; Svec, Frantisek

    2017-04-29

    This review aims at presenting the state of the art concerning monolithic materials for on-line sample preparation emphasizing solid-phase extraction, matrix exchange, and analyte conversion. Emphasis was given to organic and silica-based, as well as hybrid monoliths reported in the literature mostly after 2010. The first part of this review presents materials and strategies for enrichment of inorganic species in environmental and biological samples using mostly ICP-MS detectors. In the second part we focus on organic analytes, discussing the role of surface area of the polymer monoliths and density of adsorption sites for specific interactions, including incorporation of nanoparticles, metal organic frameworks, as well as the preparation of hybrid organic-silica monoliths to increase the surface area. Incorporation of ionic liquids to increase the number of types of interaction mechanisms available for retention is also discussed. Monoliths affording molecular recognition properties achieved by including boronate moieties for cis-diol recognition, as well as antibodies and aptamers for specific molecular recognition are also reviewed. The largest number of applications of molecular recognition mechanisms was observed for molecularly imprinted polymer monoliths as a consequence of the simplicity of this approach when compared to the use of immunosorbents or aptamers. The final part examines the on-line applications of immobilized enzyme reactors used for protein digestion in proteomic analysis and for kinetic studies in drug discovery and clinical assays usually coupling the reactors to mass spectrometers.

  5. Comparison of monolithic silica and polymethacrylate capillary columns for LC.

    PubMed

    Moravcová, Dana; Jandera, Pavel; Urban, Jiri; Planeta, Josef

    2004-07-01

    Organic polymer monolithic capillary columns were prepared in fused-silica capillaries by radical co-polymerization of ethylene dimethacrylate and butyl methacrylate monomers with azobisisobutyronitrile as initiator of the polymerization reaction in the presence of various amounts of porogenic solvent mixtures and different concentration ratios of monomers and 1-propanol, 1,4-butanediol, and water. The chromatographic properties of the organic polymer monolithic columns were compared with those of commercial silica-based particulate and monolithic capillary and analytical HPLC columns. The tests included the determination of H-u curves, column permeabilities, pore distribution by inversed-SEC measurements, methylene and polar selectivities, and polar interactions with naphthalenesulphonic acid test samples. Organic polymer monolithic capillary columns show similar retention behaviour to chemically bonded alkyl silica columns for compounds with different polarities characterized by interaction indices, Ix, but have lower methylene selectivities and do not show polar interactions with sulphonic acids. The commercial capillary and analytical silica gel-based monolithic columns showed similar selectivities and provided symmetrical peaks, indicating no significant surface heterogeneities. To allow accurate characterization of the properties of capillary monolithic columns, the experimental data should be corrected for extra-column contributions. With 0.3 mm ID capillary columns, corrections for extra-column volume contributions are sufficient, but to obtain true information on the efficiency of 0.1 mm ID capillary columns, the experimental bandwidths should be corrected for extra-column contributions to peak broadening.

  6. Phenylalanine functionalized zwitterionic monolith for hydrophobic interaction electrochromatography.

    PubMed

    Wang, Jiabin; Jia, Wenchao; Lin, Xucong; Wu, Xiaoping; Xie, Zenghong

    2013-12-01

    A novel phenylalanine (Phe) functionalized zwitterionic monolith for hydrophobic electrochromatography was prepared by a two-step procedure involving the synthesis of glycidyl methacrylate based polymer monolith and subsequent on-column chemical modification with Phe via ring-opening reaction of epoxides. Benefitting from the hydrophobicity of both methacrylate-based matrix and aromatic group of Phe, this monolith could exhibit good hydrophobic interaction for the separation. Typical RP chromatographic behavior was observed toward various solutes. The well-controlled cathodic or anodic EOF of the prepared column could be facilely switched by altering the pH values of running buffers. The separation mechanism of this Phe functionalized zwitterionic monolith is discussed in detail. Two mixed-mode mechanisms of RP/cation exchange and RP/anion exchange could be further realized on the same monolith in different pH condition of the mobile phase. Versatile separation capabilities of neutral, basic, and acidic analytes have been successfully achieved in this zwitterionic monolith by CEC method.

  7. Pepsin-modified chiral monolithic column for affinity capillary electrochromatography.

    PubMed

    Hong, Tingting; Chi, Cuijie; Ji, Yibing

    2014-11-01

    Pepsin-modified affinity monolithic capillary electrochromatography, a novel microanalysis system, was developed by the covalent bonding of pepsin on silica monolith. The column was successfully applied in the chiral separation of (±)-nefopam. Furthermore, the electrochromatographic performance of the pepsin-functionalized monolith for enantiomeric analysis was evaluated in terms of protein content, pH of running buffer, sample volume, buffer concentration, applied voltage, and capillary temperature. The relative standard deviation (%RSD) values of retention time (intraday <0.53, n = 10; interday <0.53, n = 10; column-to-column <0.70, n = 20; and batch-to-batch <0.80, n = 20) indicated satisfactory stability of these columns. No appreciable change was observed in retention and resolution for chiral recognition of (±)-nefopam in 50 days with 100 injections. The proteolytic activity of this stationary phase was further characterized with bovine serum albumin as substrate for online protein digestion. As for monolithic immobilized enzyme reactor, successive protein injections confirmed both the operational stability and ability to reuse the bioreactor for at least 20 digestions. It implied that the affinity monolith used in this research opens a new path of exploring particularly versatile class of enzymes to develop enzyme-modified affinity capillary monolith for enantioseparation.

  8. Toward homosuccinate fermentation: metabolic engineering of Corynebacterium glutamicum for anaerobic production of succinate from glucose and formate.

    PubMed

    Litsanov, Boris; Brocker, Melanie; Bott, Michael

    2012-05-01

    Previous studies have demonstrated the capability of Corynebacterium glutamicum for anaerobic succinate production from glucose under nongrowing conditions. In this work, we have addressed two shortfalls of this process, the formation of significant amounts of by-products and the limitation of the yield by the redox balance. To eliminate acetate formation, a derivative of the type strain ATCC 13032 (strain BOL-1), which lacked all known pathways for acetate and lactate synthesis (Δcat Δpqo Δpta-ackA ΔldhA), was constructed. Chromosomal integration of the pyruvate carboxylase gene pyc(P458S) into BOL-1 resulted in strain BOL-2, which catalyzed fast succinate production from glucose with a yield of 1 mol/mol and showed only little acetate formation. In order to provide additional reducing equivalents derived from the cosubstrate formate, the fdh gene from Mycobacterium vaccae, coding for an NAD(+)-coupled formate dehydrogenase (FDH), was chromosomally integrated into BOL-2, leading to strain BOL-3. In an anaerobic batch process with strain BOL-3, a 20% higher succinate yield from glucose was obtained in the presence of formate. A temporary metabolic blockage of strain BOL-3 was prevented by plasmid-borne overexpression of the glyceraldehyde 3-phosphate dehydrogenase gene gapA. In an anaerobic fed-batch process with glucose and formate, strain BOL-3/pAN6-gap accumulated 1,134 mM succinate in 53 h with an average succinate production rate of 1.59 mmol per g cells (dry weight) (cdw) per h. The succinate yield of 1.67 mol/mol glucose is one of the highest currently described for anaerobic succinate producers and was accompanied by a very low level of by-products (0.10 mol/mol glucose).

  9. In Vitro Oxidation of Collagen Promotes the Formation of Advanced Oxidation Protein Products and the Activation of Human Neutrophils.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; de Campos, Luízi Prestes; Sangoi, Manuela Borges; Fernandes, Natieli Flores; Gomes, Patrícia; Moretto, Maria Beatriz; Barbisan, Fernanda; da Cruz, Ivana Beatrice Mânica; Moresco, Rafael Noal

    2016-04-01

    The accumulation of advanced oxidation protein products (AOPPs) has been linked to several pathological conditions. Here, we investigated collagen as a potential source for AOPP formation and determined the effects of hypochlorous acid (HOCl)-treated collagen (collagen-AOPPs) on human neutrophil activity. We also assessed whether alpha-tocopherol could counteract these effects. Exposure to HOCl increased the levels of collagen-AOPPs. Collagen-AOPPs also stimulated the production of AOPPs, nitric oxide (NO), superoxide radicals (O2(-)), and HOCl by neutrophils. Collagen-AOPPs induced apoptosis and decreased the number of viable cells. Alpha-tocopherol prevented the formation of collagen-AOPPs, strongly inhibited the collagen-AOPP-induced production of O2(-) and HOCl, and increased the viability of neutrophils. Our results suggest that collagen is an important protein that interacts with HOCl to form AOPPs, and consequently, collagen-AOPP formation is related to human neutrophil activation and cell death.

  10. Polymethacrylate monolithic and hybrid particle-monolithic columns for reversed-phase and hydrophilic interaction capillary liquid chromatography.

    PubMed

    Jandera, Pavel; Urban, Jirí; Skeríková, Veronika; Langmaier, Pavel; Kubícková, Romana; Planeta, Josef

    2010-01-01

    We prepared hybrid particle-monolithic polymethacrylate columns for micro-HPLC by in situ polymerization in fused silica capillaries pre-packed with 3-5microm C(18) and aminopropyl silica bonded particles, using polymerization mixtures based on laurylmethacrylate-ethylene dimethacrylate (co)polymers for the reversed-phase (RP) mode and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl) zwitterionic (co)polymers for the hydrophilic interaction (HILIC) mode. The hybrid particle-monolithic columns showed reduced porosity and hold-up volumes, approximately 2-2.5 times lower in comparison to the pure monolithic columns prepared in the whole volume of empty capillaries. The elution volumes of sample compounds are also generally lower in comparison to packed or pure monolithic columns. The efficiency and permeability of the hybrid columns are intermediate in between the properties of the reference pure monolithic and particle-packed columns. The chemistries of the embedded solid particles and of the interparticle monolithic moiety in the hybrid capillary columns contribute to the retention to various degrees, affecting the selectivity of separation. Some hybrid columns provided improved separations of proteins in comparison to the reference particle-packed columns in the reversed-phase mode. Zwitterionic hybrid particle-monolithic columns show dual mode retention HILIC/RP behaviour depending on the composition of the mobile phase and allow separations of polar compounds such as phenolic acids in the HILIC mode at lower concentrations of acetonitrile and, often in shorter analysis time in comparison to particle-packed and full-volume monolithic columns.

  11. Use of eutectic mixtures for preparation of monolithic carbons with CO₂-adsorption and gas-separation capabilities.

    PubMed

    López-Salas, N; Jardim, E O; Silvestre-Albero, A; Gutiérrez, M C; Ferrer, M L; Rodríguez-Reinoso, F; Silvestre-Albero, J; del Monte, F

    2014-10-21

    With global warming becoming one of the main problems our society is facing nowadays, there is an urgent demand to develop materials suitable for CO2 storage as well as for gas separation. Within this context, hierarchical porous structures are of great interest for in-flow applications because of the desirable combination of an extensive internal reactive surface along narrow nanopores with facile molecular transport through broad "highways" leading to and from these pores. Deep eutectic solvents (DESs) have been recently used in the synthesis of carbon monoliths exhibiting a bicontinuous porous structure composed of continuous macroporous channels and a continuous carbon network that contains a certain microporosity and provides considerable surface area. In this work, we have prepared two DESs for the preparation of two hierarchical carbon monoliths with different compositions (e.g., either nitrogen-doped or not) and structure. It is worth noting that DESs played a capital role in the synthesis of hierarchical carbon monoliths not only promoting the spinodal decomposition that governs the formation of the bicontinuous porous structure but also providing the precursors required to tailor the composition and the molecular sieve structure of the resulting carbons. We have studied the performance of these two carbons for CO2, N2, and CH4 adsorption in both monolithic and powdered form. We have also studied the selective adsorption of CO2 versus CH4 in equilibrium and dynamic conditions. We found that these materials combined a high CO2-sorption capacity besides an excellent CO2/N2 and CO2/CH4 selectivity and, interestingly, this performance was preserved when processed in both monolithic and powdered form.

  12. Tuning preparation conditions towards optimized separation performance of thermally polymerized organo-silica monolithic columns in capillary liquid chromatography.

    PubMed

    Gharbharan, Deepa; Britsch, Denae; Soto, Gabriela; Weed, Anna-Marie Karen; Svec, Frantisek; Zajickova, Zuzana

    2015-08-21

    Tuning of preparation conditions, such as variations in the amount of a porogen, concentration of an aqueous acid catalyst, and adjustment in polymerization temperature and time, towards optimized chromatographic performance of thermally polymerized monolithic capillaries prepared from 3-(methacryloyloxy)propyltrimethoxysilane has been carried out. Performance of capillary columns in reversed-phase liquid chromatography was assessed utilizing various sets of solutes. Results describing hydrophobicity, steric selectivity, and extent of hydrogen bonding enabled comparison of performance of hybrid monolithic columns prepared under thermal (TSG) and photopolymerized (PSG) conditions. Reduced amounts of porogen in the polymerization mixture, and prolonged reaction times were necessary for the preparation of monolithic columns with enhanced retention and column efficiency that reached to 111,000 plates/m for alkylbenzenes with shorter alkyl chains. Both increased concentration of catalyst and higher temperature resulted in faster polymerization but inevitably in insufficient time for pore formation. Thermally polymerized monoliths produced surfaces, which were slightly more hydrophobic (a methylene selectivity of 1.28±0.002 TSG vs 1.20±0.002 PSG), with reduced number of residual silanols (a caffeine/phenol selectivity of 0.13±0.001 TSG vs 0.17±0.003 PSG). However, steric selectivity of 1.70±0.01 was the same for both types of columns. The batch-to-batch repeatability was better using thermal initiation compared to monolithic columns prepared under photopolymerized conditions. RSD for retention factor of benzene was 3.7% for TSG capillaries (n=42) vs. 6.6% for PSG capillaries (n=18). A similar trend was observed for columns prepared within the same batch.

  13. Expression of NAD+-dependent formate dehydrogenase in Enterobacter aerogenes and its involvement in anaerobic metabolism and H2 production.

    PubMed

    Lu, Yuan; Zhao, Hongxin; Zhang, Chong; Lai, Qiheng; Wu, Xi; Xing, Xin-Hui

    2009-10-01

    An expression system for NAD(+)-dependent formate dehydrogenase gene (fdh1), from Candida boidinii, was constructed and cloned into Enterobacter aerogenes IAM1183. With the fdh1 expression, the total H(2) yield was attributed to a decrease in activity of the lactate pathway and an increase of the formate pathway flux due to the NADH regeneration. Analysis of the redox state balance and ethanol-to-acetate ratio in the fdhl-expressed strain showed that increased reducing power arose from the reconstruction of NADH regeneration pathway from formate thereby contributing to the improved H(2) production.

  14. TolC promotes ExPEC biofilm formation and curli production in response to medium osmolarity.

    PubMed

    Hou, Bo; Meng, Xian-Rong; Zhang, Li-Yuan; Tan, Chen; Jin, Hui; Zhou, Rui; Gao, Jian-Feng; Wu, Bin; Li, Zi-Li; Liu, Mei; Chen, Huan-Chun; Bi, Ding-Ren; Li, Shao-Wen

    2014-01-01

    While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2 M9 medium. We propose for the first time that TolC protein is able to form biofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation.

  15. Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

    NASA Technical Reports Server (NTRS)

    Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

    2010-01-01

    This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows

  16. Monolithic cryopolymers with embedded nanoparticles. I. Capillary liquid chromatography of proteins using neutral embedded nanoparticles.

    PubMed

    Dario Arrua, R; Nordborg, Anna; Haddad, Paul R; Hilder, Emily F

    2013-01-18

    Rigid monolithic cryostructures were prepared in capillary format at sub-zero temperatures and used successfully in the separation of proteins by hydrophobic interaction chromatography (HIC). The polymerization mixture consisted of poly(ethyleneglycol) diacrylate (PEGDA) M(n)∼258 as the single monomer, a mixture of dioxane and water as the porogen and N,N,N',N'-tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as the initiator system. At sub-zero temperatures, the solvent mixture used as the porogen is frozen, leading to the formation of a polymeric structure templated by the solvent crystals that are formed. The optimization of the polymerization reaction was carried out by studying the influence of different reaction parameters including the temperature of the reaction, monomer concentration and solvent, on the porous characteristics of the polymers obtained. Separations were performed in HIC mode using 3 M ammonium sulfate in 0.1 M phosphate buffer, pH 6.9 to 0.1 M phosphate buffer, pH 6.9 over a 15 min gradient. The addition of neutral nanoparticles synthesized by mini-emulsion polymerization greatly improved the separation of the protein mixture, doubling the peak capacity of the control column without nanoparticles (from 7 to 17). Although the peak capacities and resolution values achieved were lower than those reported for conventional methacrylate monolithic columns, the use of this polymerization approach allows the preparation of polymeric structures which presented a more open porous structure and consequently exhibited significantly higher permeability than conventional polymer monoliths.

  17. Monolithic Nickel (II) Oxide Aerogels Using an Organic Epoxide: The Importance of the Counter Ion

    SciTech Connect

    Gash, A E; Satcher, J H; Simpson, R L

    2004-01-13

    The synthesis and characterization of nickel (II) oxide aerogel materials prepared using the epoxide addition method is described. The addition of the organic epoxide propylene oxide to an ethanolic solution of NiCl{sub 2} 6H{sub 2}O resulted in the formation of an opaque light green monolithic gel and subsequent drying with supercritical CO{sub 2} gave a monolithic aerogel material of the same color. This material has been characterized using powder X-ray diffraction, electron microscopy, elemental analysis, and nitrogen adsorption/desorption analysis. The results indicate that the nickel (II) oxide aerogel has very low bulk density (98 kg/m{sup 3} ({approx}98 %porous)), high surface area (413 m{sup 2}/g), and has a particulate-type aerogel microstructure made up of very fine spherical particles with an open porous network. By comparison, a precipitate of Ni{sub 3}(NO{sub 3}){sub 2}(OH){sub 4} is obtained when the same preparation is attempted with the common Ni(NO{sub 3}){sub 2} 6H{sub 2}O salt as the precursor. The implications of the difference of reactivity of the two different precursors are discussed in the context of the mechanism of gel formation via the epoxide addition method. The synthesis of nickel (II) oxide aerogel, using the epoxide addition method, is especially unique in our experience. It is our first example of the successful preparation of a metal oxide aerogel using a metal divalent metal ion and may have implications for the application of this method to the preparation of aerogels or nanoparticles of other divalent metal oxides. To our knowledge this is the first report of a monolithic pure nickel (II) oxide aerogel materials.

  18. There's more than one way to skin a cat: A wide selection of techniques used for the preparation of porous polymer monoliths

    PubMed Central

    Svec, Frantisek

    2010-01-01

    The porous polymer monoliths went a long way since their invention two decades ago. While the first studies applied the traditional polymerization processes at that time well established for the preparation of polymer particles, creativity of scientists interested in the monolithic structures has later led to the use of numerous less common techniques. This review article presents vast variety of methods that have meanwhile emerged. The text first briefly describes the early approaches used for the preparation of monoliths comprising standard free radical polymerizations and includes their development up to present days. Specific attention is paid to the effects of process variables on the formation of both porous structure and pore surface chemistry. Specific attention is also devoted to the use of photopolymerization. Then, several less common free radical polymerization techniques are presented in more detail such as those initiated by γ-rays and electron beam, the preparation of monoliths from high internal phase emulsions, and cryogels. Living processes including stable free radicals, atom transfer radical polymerization, and ring opening metathesis polymerization are also discussed. The review ends with description of preparation methods based on polycondensation and polyaddition reactions as well as on precipitation of preformed polymers affording the monolithic materials. PMID:19828151

  19. The synthesis of surface-glycosylated porous monolithic column via aqueous two-phase graft copolymerization and its application in capillary-liquid chromatography.

    PubMed

    Xiong, Xiyue; He, Haiqin; Shu, Yan; Li, Yuxin; Yang, Zihui; Chen, Yingzhuang; Ma, Ming; Chen, Bo

    2016-12-01

    A facile, flexible process was developed for the preparation of surface-glycosylated porous monolithic columns via aqueous two-phase graft copolymerization of polyethylene glycol diacrylate (PEGDA) and water-soluble dextran (dextran sulfate). The formation of poly(PEGDA) porous skeletons and surface glycosylation were achieved via a one-step process without pre-modification of the dextran. The synthesis conditions were thoroughly optimized. The optimal monolithic column exhibited a large dry state surface area (greater than 400m(2)/g), and it was evaluated as a hydrophilic liquid chromatography (HILIC) stationary phase. A typical HILIC mechanism was observed at high organic solvent content (≥65% acetonitrile). In addition, the resulting monolithic column demonstrated the potential use in analysis of complex biological sample and enviroment water.

  20. Biofilm formation and indole-3-acetic acid production by two rhizospheric unicellular cyanobacteria.

    PubMed

    Ahmed, Mehboob; Stal, Lucas J; Hasnain, Shahida

    2014-08-01

    Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants.

  1. Predicting the formation and the dispersion of toxic combustion products from the fires of dangerous substances

    NASA Astrophysics Data System (ADS)

    Nevrlý, V.; Bitala, P.; Danihelka, P.; Dobeš, P.; Dlabka, J.; Hejzlar, T.; Baudišová, B.; Míček, D.; Zelinger, Z.

    2012-04-01

    Natural events, such as wildfires, lightning or earthquakes represent a frequent trigger of industrial fires involving dangerous substances. Dispersion of smoke plume from such fires and the effects of toxic combustion products are one of the reference scenarios expected in the framework of major accident prevention. Nowadays, tools for impact assessment of these events are rather missing. Detailed knowledge of burning material composition, atmospheric conditions, and other factors are required in order to describe quantitatively the source term of toxic fire products and to evaluate the parameters of smoke plume. Nevertheless, an assessment of toxic emissions from large scale fires involves a high degree of uncertainty, because of the complex character of physical and chemical processes in the harsh environment of uncontrolled flame. Among the others, soot particle formation can be mentioned as still being one of the unresolved problems in combustion chemistry, as well as decomposition pathways of chemical substances. Therefore, simplified approach for estimating the emission factors from outdoor fires of dangerous chemicals, utilizable for major accident prevention and preparedness, was developed and the case study illustrating the application of the proposed method was performed. ALOFT-FT software tool based on large eddy simulation of buoyant fire plumes was employed for predicting the local toxic contamination in the down-wind vicinity of the fire. The database of model input parameters can be effectively modified enabling the simulation of the smoke plume from pool fires or jet fires of arbitrary flammable (or combustible) gas, liquid or solid. This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic via the project LD11012 (in the frame of the COST CM0901 Action) and the Ministry of Environment of the Czech Republic (project no. SPII 1a10 45/70).

  2. Global view of sea-ice production in polynyas and its linkage to dense/bottom water formation

    NASA Astrophysics Data System (ADS)

    Ohshima, Kay I.; Nihashi, Sohey; Iwamoto, Katsushi

    2016-12-01

    Global overturning circulation is driven by density differences. Saline water rejected during sea-ice formation in polynyas is the main source of dense water, and thus sea-ice production is a key factor in the overturning circulation. Due to difficulties associated with in situ observation, sea-ice production and its interannual variability have not been well understood until recently. Methods to estimate sea-ice production on large scales have been developed using heat flux calculations based on satellite microwave radiometer data. Using these methods, we present the mapping of sea-ice production with the same definition and scale globally, and review the polynya ice production and its relationship with dense/bottom water. The mapping demonstrates that ice production rate is high in Antarctic coastal polynyas, in contrast to Arctic coastal polynyas. This is consistent with the formation of Antarctic Bottom Water (AABW), the densest water mass which occupies the abyssal layer of the global ocean. The Ross Ice Shelf polynya has by far the highest ice production in the Southern Hemisphere. The Cape Darnley polynya (65°E-69°E) is found to be the second highest production area and recent observations revealed that this is the missing (fourth) source of AABW. In the region off the Mertz Glacier Tongue (MGT), the third source of AABW, sea-ice production decreased by as much as 40 %, due to the MGT calving in early 2010, resulting in a significant decrease in AABW production. The Okhotsk Northwestern polynya exhibits the highest ice production in the Northern Hemisphere, and the resultant dense water formation leads to overturning in the North Pacific, extending to the intermediate layer. Estimates of its ice production show a significant decrease over the past 30-50 years, likely causing the weakening of the North Pacific overturning. These regions demonstrate the strong linkage between variabilities of sea-ice production and bottom/intermediate water formation. The

  3. Effect of bioconversion conditions on vanillin production by Amycolatopsis sp. ATCC 39116 through an analysis of competing by-product formation.

    PubMed

    Ma, Xiao-kui; Daugulis, Andrew J

    2014-05-01

    This study investigated the effects of transformation conditions such as initial pH, the initial concentration of glucose and yeast extract in the medium, and the separate addition of ferulic acid and vanillic acid, on the production of vanillin through an analysis of competing by-product formation by Amycolatopsis sp. ATCC 39116. The extent and nature of by-product formation and vanillin yield were affected by initial pH and different initial concentrations of glucose and yeast extract in the medium, with a high yield of vanillin and high cell density obtained at pH 8.0, 10 g/l glucose, and 8 g/l yeast extract. High concentrations of ferulic acid were found to negatively affect cell density. Additional supplementation of 100 mg/l vanillic acid, a metabolically linked by-product, was found to result in a high concentration of vanillin and guaiacol, an intermediate of vanillin. Via an analysis of the effect of these transformation conditions on competing by-product formation, high concentrations of ferulic acid were transformed with a molar yield to vanillin of 96.1 and 95.2 %, by Amycolatopsis sp. ATCC 39116 and Streptomyces V1, respectively, together with a minor accumulation of by-products. These are among the highest performance values reported in the literature to date for Streptomyces in batch cultures.

  4. Constituents from Polygonatum sibiricum and their inhibitions on the formation of advanced glycosylation end products.

    PubMed

    Wang, Juan; Lu, Cheng-Shu; Liu, Dong-Yan; Xu, Yan-Tong; Zhu, Yan; Wu, Hong-Hua

    2016-07-01

    A new saponin, isonarthogenin 3-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (1), together with twelve known compounds, were isolated from the rhizomes of Polygonatum sibiricum. The structures of these compounds were elucidated by analysis of their 1D/2D NMR and MS data. Among them, phenol compounds 4-7 and 9-10 showed significant inhibitions against the formation of advanced glycosylation end products, with IC50 values of 0.091 ± 0.0021, 0.10 ± 0.041, 0.014 ± 0.0027, 0.11 ± 0.011, 0.13 ± 0.045, and 0.055 ± 0.019 μM, respectively. The results will promote exploiting potential medicinal use of these compounds in the prevention of diabetic complications and supporting Polygonatum sibiricum as a functional food for healthy and medicinal diet.

  5. Directed enzyme evolution and selections for catalysis based on product formation.

    PubMed

    Jestin, Jean-Luc; Kaminski, Pierre Alexandre

    2004-09-30

    Enzyme engineering by molecular modelling and site-directed mutagenesis can be remarkably efficient. Directed enzyme evolution appears as a more general strategy for the isolation of catalysts as it can be applied to most chemical reactions in aqueous solutions. Selections, as opposed to screening, allow the simultaneous analysis of protein properties for sets of up to about 10(14) different proteins. These approaches for the parallel processing of molecular information 'Is the protein a catalyst?' are reviewed here in the case of selections based on the formation of a specific reaction product. Several questions are addressed about in vivo and in vitro selections for catalysis reported in the literature. Can the selection system be extended to other types of enzymes? Does the selection control regio- and stereo-selectivity? Does the selection allow the isolation of enzymes with an efficient turnover? How should substrates be substituted or mimicked for the design of efficient selections while minimising the number of chemical synthesis steps? Engineering sections provide also some clues to design selections or to circumvent selection biases. A special emphasis is put on the comparison of in vivo and in vitro selections for catalysis.

  6. Factors impacting the formation of monochloropropanediol (MCPD) fatty acid diesters during palm (Elaeis guineensis) oil production.

    PubMed

    Craft, Brian D; Nagy, Kornél; Sandoz, Laurence; Destaillats, Frédéric

    2012-01-01

    Recently, organic and inorganic chlorinated compounds were detected in crude and commercially refined palm oils. Further, the predominant formation mechanism of monochloropropanediol (MCPD) diesters at high temperatures (>170-180°C) was revealed. The present study involved the development and comparison of solutions to mitigate MCPD diester levels in oils from various stages of palm oil production. Partially refined palm oil samples and oil extracted from fresh palm fruits were submitted to bench-top deodorisation experiments. Application of glycerol and ethanol as refining aids during the deodorisation of refined-bleached palm oil proved to be moderately effective; about 25%-35% reduction of MCPD diester levels was achieved. Washing crude palm oil with ethanol-water (1:1) prior to deodorisation was also an effective strategy yielding an ∼30% reduction of MCPD diester contents. Washing palm fruit pulp before oil extraction, however, was most impactful, resulting in a 95% reduction of MCPD diesters when compared to the deodorised control oil. This suggests that intervention upstream in the process chain is most efficient in reducing levels of these contaminants in refined oils. Following the study, a root-cause analysis was performed in order to map the parameters potentially responsible for the occurrence of MCPD diesters in refined palm oil and related fractions.

  7. Evaporation Rate Study and NDMA Formation from UDMH/NO2 Reaction Products

    NASA Technical Reports Server (NTRS)

    Buchanan, Vanessa D.; Dee, Louis A.; Baker, David L.

    2003-01-01

    Laboratory samples of uns-dimethylhydrazine (UDMH) fuel/oxidizer (nitrogen dioxide) non-combustion reaction products (UFORP) were prepared using a unique permeation tube technology. Also, a synthetic UFORP was prepared from UDMH, N-nitrosodimethylamine (NDMA), dimethylammonium nitrate, sodium nitrite and purified water. The evaporation rate of UFORP and synthetic UFORP was determined under space vacuum (approx 10(exp -3) Torr) at -40 ?C and 0 ?C. The material remaining was analyzed and showed that the UFORP weight and NDMA concentration decreased over time; however, NDMA had not completely evaporated. Over 85% of the weight was removed by subjecting the UFORP to 10(-3) Torr for 7 hours at -40 ?C and 4 hours at 0 ?C. A mixture of dimethylammonium nitrate and sodium nitrite formed NDMA at a rapid rate in a moist air environment. A sample of UFORP residue was analyzed for formation of NDMA under various conditions. It was found that NDMA was not formed unless nitrite was added.

  8. Syringe test screening of microbial gas production activity: Cases denitrification and biogas formation.

    PubMed

    Østgaard, Kjetill; Kowarz, Viktoria; Shuai, Wang; Henry, Ingrid A; Sposob, Michal; Haugen, Hildegunn Hegna; Bakke, Rune

    2017-01-01

    Mass produced plastic syringes may be applied as vessels for cheap, simple and large scale batch culture testing. As illustrated for the cases of denitrification and of biogas formation, metabolic activity was monitored by direct reading of the piston movement due to the gas volume formed. Pressure buildup due to friction was shown to be moderate. A piston pull and slide back routine can be applied before recording gas volume to minimize experimental errors due to friction. Inoculum handling and activity may be conveniently standardized as illustrated by applying biofilm carriers. A robust set of positive as well as negative controls ("blanks") should be included to ensure quality of the actual testing. The denitrification test showed saturation response at increasing amounts of inoculum in the form of adapted moving bed biofilm reactor (MBBR) carriers, with well correlated nitrate consumption vs. gas volume formed. As shown, the denitrification test efficiently screened different inocula at standardized substrates. Also, different substrates were successfully screened and compared at standardized inocula. The biogas potential test showed efficient screening of different substrates with effects of relative amounts of carbohydrate, protein, fat. A second case with CO2 capture reclaimer waste as substrate demonstrated successful use of co-feeding to support waste treatment and how temperature effects on kinetics and stoichiometry can be observed. In total, syringe test screening of microbial gas production seems highly efficient at a low cost when properly applied.

  9. Presenilin and nicastrin regulate each other and determine amyloid β-peptide production via complex formation

    PubMed Central

    Edbauer, Dieter; Winkler, Edith; Haass, Christian; Steiner, Harald

    2002-01-01

    Amyloid β-peptide (Aβ) is generated by the consecutive cuts of two membrane-bound proteases. β-Secretase cuts at the N terminus of the Aβ domain, whereas γ-secretase mediates the C-terminal cut. Recent evidence suggests that the presenilin (PS) proteins, PS1 and PS2, may be γ-secretases. Because PSs principally exist as high molecular weight protein complexes, biologically active γ-secretases likely require other cofactors such as nicastrin (Nct) for their activities. Here we show that preferentially mature Nct forms a stable complex with PSs. Furthermore, we have down-regulated Nct levels by using a highly specific and efficient RNA interference approach. Very similar to a loss of PS function, down-regulation of Nct levels leads to a massive accumulation of the C-terminal fragments of the β-amyloid precursor protein. In addition, Aβ production was markedly reduced. Strikingly, down-regulation of Nct destabilized PS and strongly lowered levels of the high molecular weight PS1 complex. Interestingly, absence of the PS1 complex in PS1−/− cells was associated with a strong down-regulation of the levels of mature Nct, suggesting that binding to PS is required for trafficking of Nct through the secretory pathway. Based on these findings we conclude that Nct and PS regulate each other and determine γ-secretase function via complex formation. PMID:12048259

  10. Natural gas production from Ordovician Queenston Formation in West Auburn field, Cayuga County, New York

    SciTech Connect

    Ward, T.L.

    1988-08-01

    Gas has been produced from the Upper Ordovician Queenston Formation at West Auburn field, Cayuga County, New York, for over 20 years. This field indicates Queenston production to be long lived, with substantially economic reserves found at depths shallower than 2,000 ft. Locally, The Queenston is comprised of sand and silty shale with the primary reservoirs found in quartzose sandstones. The overall thickness of the Queenston clastic interval is over 700 ft with gas found in the upper 300 ft. Three primary gas sands are continuous across the field area and have high average porosities of as much as 13.0% and average permeabilities of 0.20 md. Extreme examples show peak porosities approaching 20% and permeabilities of over 5.0 md. The reservoir is composed of very fine to medium-grained, moderately sorted, red sandstone. Sand grains are predominantly quartz with minor amounts of feldspar. The main pore-filling constituent is abundant authigenic clay with iron oxides, thus contributing to reduced permeabilities. These sands vary in reservoir quality through the field and, hence, allow for stratigraphic trapping of the gas. Other factors involved include the updip accumulation of gas against the Silurian-Ordovician unconformity at the top of the Queenston. Some of the pay sands are absent due to this unconformity in the area farthest updip and, therefore, decrease the overall reserve potential of the individual well in that part of the field.

  11. Identification of the Genes Involved in the Fruiting Body Production and Cordycepin Formation of Cordyceps militaris Fungus

    PubMed Central

    Zheng, Zhuang-li; Qiu, Xue-hong

    2015-01-01

    A mutant library of Cordyceps militaris was constructed by improved Agrobacterium tumefaciens-mediated transformation and screened for degradation features. Six mutants with altered characters in in vitro and in vivo fruiting body production, and cordycepin formation were found to contain a single copy T-DNA. T-DNA flanking sequences of these mutants were identified by thermal asymmetric interlaced-PCR approach. ATP-dependent helicase, cytochrome oxidase subunit I and ubiquitin-like activating enzyme were involved in in vitro fruiting body production, serine/threonine phosphatase involved in in vivo fruiting body production, while glucose-methanol-choline oxidoreductase and telomerase reverse transcriptase involved in cordycepin formation. These genes were analyzed by bioinformatics methods, and their molecular function and biology process were speculated by Gene Ontology (GO) analysis. The results provided useful information for the control of culture degeneration in commercial production of C. militaris. PMID:25892913

  12. Solid oxide fuel cell having monolithic core

    DOEpatents

    Ackerman, J.P.; Young, J.E.

    1983-10-12

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002 to 0.05 cm thick.

  13. Solid oxide fuel cell having monolithic core

    DOEpatents

    Ackerman, John P.; Young, John E.

    1984-01-01

    A solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween, and each interconnect wall consists of thin layers of the cathode and anode materials sandwiching a thin layer of interconnect material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002-0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002-0.05 cm thick.

  14. The 30-GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Sokolov, V.; Geddes, J.; Bauhahn, P.

    1983-01-01

    Key requirements for a 30 GHz GaAs monolithic receive module for spaceborne communication antenna feed array applications include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five-bit phase shifter, and a maximum power consumption of 250 mW. The RF designs for each of the four submodules (low noise amplifier, some gain control, phase shifter, and RF to IF sub-module) are presented. Except for the phase shifter, high frequency, low noise FETs with sub-half micron gate lengths are employed in the submodules. For the gain control, a two stage dual gate FET amplifier is used. The phase shifter is of the passive switched line type and consists of 5-bits. It uses relatively large gate width FETs (with zero drain to source bias) as the switching elements. A 20 GHz local oscillator buffer amplifier, a FET compatible balanced mixer, and a 5-8 GHz IF amplifier constitute the RF/IF sub-module. Phase shifter fabrication using ion implantation and a self-aligned gate technique is described. Preliminary RF results obtained on such phase shifters are included.

  15. Solid oxide fuel cell with monolithic core

    DOEpatents

    McPheeters, Charles C.; Mrazek, Franklin C.

    1988-01-01

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700.degree. C. and 1100.degree. C.

  16. Solid oxide fuel cell with monolithic core

    DOEpatents

    McPheeters, C.C.; Mrazek, F.C.

    1988-08-02

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700 C and 1,100 C. 8 figs.

  17. Experiments of a monolithic radial transmission line

    NASA Astrophysics Data System (ADS)

    Mao, C.; Wang, X.; Zou, X.; Lehr, J.

    2016-11-01

    This paper presents the experimental results of a monolithic radial transmission line (MRTL) that may be used in pulsed power generators and microwave devices. The MRTL with a hyperbolic impedance profile is 508 mm in radius, corresponding to a one-way transit time of 15 ns for the electromagnetic wave. In the experiments, up to twenty identical voltage pulses, 10 ns in FWHM and 2 ns in rise-time, were fed into the MRTL through 20 input BNC connectors that are uniformly distributed along the outer circumference of the MRTL. It was found that the amplitude of the voltage from the output BNC connector located in the center of the MRTL is nearly proportional to the total number of the input branches. The effect of the failure modes on the output voltage was investigated. For the MRTL driven by 20 input branches, while the open-circuit or short-circuit even in one input branch considerably decreases the amplitude of the output voltage, the jitter shorter than 2 ns in 3 input branches makes no obvious effect on the output voltage.

  18. Dedicated monolithic infrared spectrometer for process monitoring

    NASA Astrophysics Data System (ADS)

    Chadha, Suneet; Kyle, William; Bolduc, Roy A.; Curtiss, Lawrence E.

    1999-12-01

    Foster-Miller has leveraged its innovations in IR fiber- optic probes and the recent development of a miniature spectrometer to build a novel IR sensor system for process applications. The developed sensor systems is a low-cost alternative to process FTIR and filter based systems. A monolithic wedge-grating optic provides the spectral dispersion with low cost thermopile point or array detectors picking off the diffracted wavelengths from the optic. The integrated optic provides spectral discrimination between 3- 12 micrometers with resolution at 8 cm-1 or better and high overall optical throughput. The device has a fixed cylindrical grating uniquely bonded to the edge of a ZnSe conditioning 'wedge'. The conditioning optic overcomes limitations of concave gratings as it accepts high angle light at the narrow end of the wedge and progressively conditions it to be near normal to the grating. On return, the diffracted wavelengths are concentrated on the discrete or array detector elements by the wedge, providing throughput comparable to that of an FTIR. The miniature spectrometer coupled to flow through liquid cells or multipass gas cells provides significant cost advantage over conventional sampling methodologies. Currently, we are investigating process applications for the petroleum and dairy markets. The sensor system eliminates the cost, complexity, reliability and bandwidth/resolution problems associated with either Fabry Perot or Michelson Interferometer based approaches for low-cost process applications.

  19. Neutron spectrometry with a monolithic silicon telescope.

    PubMed

    Agosteo, S; D'Angelo, G; Fazzi, A; Para, A Foglio; Pola, A; Zotto, P

    2007-01-01

    A neutron spectrometer was set-up by coupling a polyethylene converter with a monolithic silicon telescope, consisting of a DeltaE and an E stage-detector (about 2 and 500 microm thick, respectively). The detection system was irradiated with monoenergetic neutrons at INFN-Laboratori Nazionali di Legnaro (Legnaro, Italy). The maximum detectable energy, imposed by the thickness of the E stage, is about 8 MeV for the present detector. The scatter plots of the energy deposited in the two stages were acquired using two independent electronic chains. The distributions of the recoil-protons are well-discriminated from those due to secondary electrons for energies above 0.350 MeV. The experimental spectra of the recoil-protons were compared with the results of Monte Carlo simulations using the FLUKA code. An analytical model that takes into account the geometrical structure of the silicon telescope was developed, validated and implemented in an unfolding code. The capability of reproducing continuous neutron spectra was investigated by irradiating the detector with neutrons from a thick beryllium target bombarded with protons. The measured spectra were compared with data taken from the literature. Satisfactory agreement was found.

  20. The Structure and Properties of Carbon Fiber Based Adsorbent Monoliths

    SciTech Connect

    Burchell, T.; Judkins, R.R.; Rogers, M.R.; Shaw, W.S.

    1998-11-06

    Carbon fiber monoliths manufactured by a novel slurry molding process from isotropic pitch-derived fibers are being developed at ORNL for gas separation and storage applications [1]. Low density (p = 0.2 - 0,3 g/cm3) monoliths have been successfully demonstrated to have an acceptable pressure drop for gas separation applications and are currently being developed for C02/CH4 separations, whereas monoliths with densities in the range p = 0.4 - 0.6 g/cm3 have been "shown to have natural gas storage capacities of >100 VIV at 500 psi pressure and room temperature. Thermal conductivity, as a function of temperature, was measured using the LASER flash, thermal- pulse method. Another approach to minimizing the temperature gradients that develop in a storage bed is to increase the thermal conductivity of the adsorbent carbon. To this end, we have developed hybrid monoliths that contain small fractions of mesophase pitch- derived carbon fibers. Our hybrid monoliths exhibit thermal conductivities in the range 0.2-0.9 W/m.K depending on the blend and density of the monolith. In comparison, a packed bed of granular carbon at comparable density would have a thermal conductivity of approximately 0.1 W/m.K [ 1 ]. The thermal conductivities of several of the hybrid The improved thermal conductivity of our monoliths is attributed to the bonding between the fibers and the incorporation of high thermal conductivity, mesophase pitch-derived carbon fibers. These features are visible in the SEM micrograph in Fig. 4.

  1. Monolithic supports with unique geometries and enhanced mass transfer.

    SciTech Connect

    Stuecker, John Nicholas; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-01-01

    The catalytic combustion of natural gas has been the topic of much research over the past decade. Interest in this technology results from a desire to decrease or eliminate the emissions of harmful nitrogen oxides (NOX) from gas turbine power plants. A low-pressure drop catalyst support, such as a ceramic monolith, is ideal for this high-temperature, high-flow application. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. 'Robocasting' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low pressure drops. This report details the mass transfer effects for novel 3-dimensional robocast monoliths, traditional honeycomb-type monoliths, and ceramic foams. The mass transfer limit is experimentally determined using the probe reaction of CO oxidation over a Pt / {gamma}-Al{sub 2}O{sub 3} catalyst, and the pressure drop is measured for each monolith sample. Conversion versus temperature data is analyzed quantitatively using well-known dimensionless mass transfer parameters. The results show that, relative to the honeycomb monolith support, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application.

  2. Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols.

    PubMed

    Abdallah, Hossam M; El-Bassossy, Hany; Mohamed, Gamal A; El-Halawany, Ali M; Alshali, Khalid Z; Banjar, Zainy M

    2016-02-22

    Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3',4,5',6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2-4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1-4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

  3. Fabrication of poly(γ-glutamic acid) monolith by thermally induced phase separation and its application.

    PubMed

    Park, Sung-Bin; Fujimoto, Takashi; Mizohata, Eiichi; Inoue, Tsuyoshi; Sung, Moon-Hee; Uyama, Hiroshi

    2013-01-01

    Monoliths are functional porous materials with a three-dimensional continuous interconnected pore structure in a single piece. A monolith with uniform shape based on poly(γ-glutamic acid) (PGA) has been prepared via a thermally induced phase separation technique using a mixture of dimethyl sulfoxide, water, and ethanol as solvent. The morphology of the obtained monolith was observed by scanning electron microscopy and the surface area of the monolith was evaluated by the Brunauer Emmett Teller method. The effects of fabrication parameters such as the concentration and molecular mass of PGA and the solvent composition have been systematically investigated. The PGA monolith was cross-linked with hexamethylene diisocyanate to produce the water-insoluble monolith. The addition of sodium chloride to the phase separation solvent affected the properties of the cross-linked monolith. The swelling ratio of the cross-linked monolith toward aqueous solutions depended on the buffer pH as well as the monolith fabrication condition. Copper(II) ion was efficiently adsorbed on the cross-linked PGA monolith, and the obtained copper-immobilized monolith showed strong antibacterial activity for Escherichia coli. By combination of the characteristic properties of PGA (e.g., high biocompatibility and biodegradability) and the unique features of monoliths (e.g., through-pore structure, large surface area, and high porosity with small pore size), the PGA monolith possesses large potentials for various industrial applications in the biomedical, environmental, analytical, and separation fields.

  4. 9 CFR 205.102 - Name of person subjecting a farm product to a security interest, on EFS and master list-format.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... product to a security interest, on EFS and master list-format. 205.102 Section 205.102 Animals and Animal... of person subjecting a farm product to a security interest, on EFS and master list—format. On an EFS, and on a master list, the name of the person subjecting a farm product to a security interest...

  5. THE GAS PHASE REACTION OF OZONE WITH 1,3-BUTADIENE: FORMATION YIELDS OF SOME TOXIC PRODUCTS. (R826236)

    EPA Science Inventory

    The formation yields of acrolein, 1,2-epoxy-3-butene and OH radicals have been measured from reaction of ozone with 1,3-butadiene at room temperature and atmosphere pressure. 1,3,5-Trimethyl benzene was added to scavenge OH radicals in measurements of product yields. In separa...

  6. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    NASA Astrophysics Data System (ADS)

    Yang, Zhen; Kong, Fanxiang

    2013-07-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  7. Formation of deoxidization products in iron ingot by the addition of Al, Si, and/or Mn (M-5)

    NASA Technical Reports Server (NTRS)

    Fukazawa, Akira

    1993-01-01

    The objective of this work is to examine the morphology, composition, and distribution of deoxidation products in iron and iron-10 percent Ni alloy ingots. The deoxidation agents Si, Mn, Al, and their mixtures are selected to investigate the formation mechanism of the deoxidation products and to compare the differences of oxide formation among these agents in microgravity. After the experiment in space, the tested specimens are going to be analyzed by the use of the latest physical and/or chemical analytical equipment, and the information obtained will be a great help for the comprehension of the formation of oxide inclusion in steel for practical purposes, and also for the study of the solidification mechanism theory in the theoretical field.

  8. Influence of the hydrothermal treatment on the chromatographic properties of monolithic silica capillaries for nano-liquid chromatography or capillary electrochromatography.

    PubMed

    Puy, G; Roux, R; Demesmay, C; Rocca, J-L; Iapichella, J; Galarneau, A; Brunel, D

    2007-08-10

    In the last decade, silica monolithic capillaries have focused more and more attention on miniaturized separation techniques like capillary electrochromatography (CEC), nano-liquid chromatography (nano-LC) and chip electrochromatography owing to their unique chromatographic properties and their simplified preparation compared with packed columns. They are synthesized according to a sol-gel multi-step process that includes, after a gelation step at 40 degrees C leading to the formation of the macropores network and the silica skeleton, a post-gelation step (hydrothermal treatment at 120 degrees C in basic medium) that allows to tailor the mesopores and finally a calcination or a washing step to remove remaining polymers. In order to reduce the synthesis time, the number of synthesis steps and above all the temperature synthesis, to adapt the synthesis of such silica monoliths in polymeric microsystem devices, we extensively studied the influence of the hydrothermal treatment and its duration on textural (pore size distribution) and chromatographic properties (retention, efficiency) of in situ-synthesized capillary monoliths in nano-LC and CEC. This study was performed on pure silica and octyl chains grafted silica monoliths. Untreated monoliths show small pores (<6 nm), whereas hydrothermally treated monoliths exhibit medium and large mesopores (8-17 nm). It was demonstrated that the hydrothermal treatment at 120 degrees C was not necessary for pure silica monolithic capillaries dedicated to normal phase liquid chromatography or hydrophilic interaction liquid chromatography (HILIC) and electrochromatography: the suppression of the hydrothermal treatment did not impair efficiencies in CEC and in nano-LC but contributed to increase in retention factors. Minimal plate heights of ca. 5 microm in CEC and 6 microm in nano-LC were obtained with or without hydrothermal treatment with bare silica. In the same way, the hydrothermal treatment was not necessary for grafted

  9. Advanced Gasification Mercury/Trace Metal Control with Monolith Traps

    SciTech Connect

    Musich, Mark; Swanson, Michael; Dunham, Grant; Stanislowski, Joshua

    2010-10-05

    Two Corning monoliths and a non-carbon-based material have been identified as potential additives for mercury capture in syngas at temperatures above 400°F and pressure of 600 psig. A new Corning monolith formulation, GR-F1-2189, described as an active sample appeared to be the best monolith tested to date. The Corning SR Liquid monolith concept continues to be a strong candidate for mercury capture. Both monolith types allowed mercury reduction to below 5-μg/m{sup 3} (~5 ppb), a current U.S. Department of Energy (DOE) goal for trace metal control. Preparation methods for formulating the SR Liquid monolith impacted the ability of the monolith to capture mercury. The Energy & Environmental Research Center (EERC)-prepared Noncarbon Sorbents 1 and 2 appeared to offer potential for sustained and significant reduction of mercury concentration in the simulated fuel gas. The Noncarbon Sorbent 1 allowed sustained mercury reduction to below 5-μg/m{sup 3} (~5 ppb). The non-carbon-based sorbent appeared to offer the potential for regeneration, that is, desorption of mercury by temperature swing (using nitrogen and steam at temperatures above where adsorption takes place). A Corning cordierite monolith treated with a Group IB metal offered limited potential as a mercury sorbent. However, a Corning carbon-based monolith containing prereduced metallic species similar to those found on the noncarbon sorbents did not exhibit significant or sustained mercury reduction. EERC sorbents prepared with Group IB and IIB selenide appeared to have some promise for mercury capture. Unfortunately, these sorbents also released Se, as was evidenced by the measurement of H2Se in the effluent gas. All sorbents tested with arsine or hydrogen selenide, including Corning monoliths and the Group IB and IIB metal-based materials, showed an ability to capture arsine or hydrogen selenide at 400°F and 600 psig. Based on current testing, the noncarbon metal-based sorbents appear to be the most

  10. ADVANCED GASIFICATION MERCURY/TRACE METAL CONTROL WITH MONOLITH TRAPS

    SciTech Connect

    Mark A. Musich; Michael L. Swanson; Grant E. Dunham; Joshua J. Stanislowski

    2010-07-31

    Two Corning monoliths and a non-carbon-based material have been identified as potential additives for mercury capture in syngas at temperatures above 400°F and pressure of 600 psig. A new Corning monolith formulation, GR-F1-2189, described as an active sample appeared to be the best monolith tested to date. The Corning SR Liquid monolith concept continues to be a strong candidate for mercury capture. Both monolith types allowed mercury reduction to below 5-μg/m3 (~5 ppb), a current U.S. Department of Energy (DOE) goal for trace metal control. Preparation methods for formulating the SR Liquid monolith impacted the ability of the monolith to capture mercury. The Energy & Environmental Research Center (EERC)-prepared Noncarbon Sorbents 1 and 2 appeared to offer potential for sustained and significant reduction of mercury concentration in the simulated fuel gas. The Noncarbon Sorbent 1 allowed sustained mercury reduction to below 5-μg/m3 (~5 ppb). The non-carbon-based sorbent appeared to offer the potential for regeneration, that is, desorption of mercury by temperature swing (using nitrogen and steam at temperatures above where adsorption takes place). A Corning cordierite monolith treated with a Group IB metal offered limited potential as a mercury sorbent. However, a Corning carbon-based monolith containing prereduced metallic species similar to those found on the noncarbon sorbents did not exhibit significant or sustained mercury reduction. EERC sorbents prepared with Group IB and IIB selenide appeared to have some promise for mercury capture. Unfortunately, these sorbents also released Se, as was evidenced by the measurement of H2Se in the effluent gas. All sorbents tested with arsine or hydrogen selenide, including Corning monoliths and the Group IB and IIB metal-based materials, showed an ability to capture arsine or hydrogen selenide at 400°F and 600 psig. Based on current testing, the noncarbon metal-based sorbents appear to be the most effective arsine

  11. Formation of iodinated disinfection by-products during oxidation of iodide-containing water with potassium permanganate.

    PubMed

    Ye, Tao; Xu, Bin; Lin, Yi-Li; Hu, Chen-Yan; Xia, Sheng-Ji; Lin, Lin; Mwakagenda, Seleli Andrew; Gao, Nai-Yun

    2012-11-30

    This study shows that iodinated disinfection by-products (I-DBPs) including iodoform (IF), iodoacetic acid (IAA) and triiodoacetic acid (TIAA) can be produced when iodide-containing waters are in contact with potassium permanganate. IF was found as the major I-DBP species during the oxidation. Iodide was oxidized to HOI, I(2) and I(3)(-), consequently, which led to the formation of iodinated organic compounds. I-DBPs varied with reaction time, solution pH, initial concentrations of iodide and potassium permanganate. Yields of IF, IAA and TIAA increased with reaction time and considerable I-DBPs were formed within 12 h. Peak IF yields were found at circumneutral pH range. However, formation of IAA and TIAA was favored under acidic conditions. Molar ratio of iodide to potassium permanganate showed significant influence on formation of IF, IAA and TIAA. The formation of IF, IAA and TIAA also depended on the characteristics of the waters.

  12. Influence of Various Promotors and Inhibitors of Soot Formation on the Production of Soot Nuclei

    NASA Astrophysics Data System (ADS)

    Agafonov, G. L.; Lyubimov, A. V.; Smirnov, V. N.; Sokolova, I. L.; Tereza, A. M.; Vlasov, P. A.

    Soot formation during pyrolysis and oxidation of rich mixtures of aliphatic hydrocarbons with single and multiple bonds in the presence of promotors (aromatic and metalorganic compounds) and inhibitors (hydrogen additives) of soot formation is experimentally studied behind reflected shock waves and simulated within the framework of a proposed kinetic mechanism. The influence of small additives of toluene to propane was demonstrated to substantially promote soot formation, whereas iron pentacarbonyl addition to propane and acetylene was shown to dramatically widen the temperature interval of soot formation both to higher and lower temperatures. Soot particles formed in the presence of iron pentacarbonyl gained magnetic properties due to the formation of an iron core inside the soot particle. The influence of acetone and propane additives to acetylene/argon mixtures was also studied. This is important to estimate the influence of impurities inherent to commercially manufactured acetylene. Hydrogen additives to acetylene/Ar mixtures were found to suppress the process of soot formation.

  13. New Graphene Form of Nanoporous Monolith for Excellent Energy Storage.

    PubMed

    Bi, Hui; Lin, Tianquan; Xu, Feng; Tang, Yufeng; Liu, Zhanqiang; Huang, Fuqiang

    2016-01-13

    Extraordinary tubular graphene cellular material of a tetrahedrally connected covalent structure was very recently discovered as a new supermaterial with ultralight, ultrastiff, superelastic, and excellent conductive characteristics, but no high specific surface area will keep it from any next-generation energy storage applications. Herein, we prepare another new graphene monolith of mesoporous graphene-filled tubes instead of hollow tubes in the reported cellular structure. This graphene nanoporous monolith is also composed of covalently bonded carbon network possessing high specific surface area of ∼1590 m(2) g(-1) and electrical conductivity of ∼32 S cm(-1), superior to graphene aerogels and porous graphene forms self-assembled by graphene oxide. This 3D graphene monolith can support over 10 000 times its own weight, significantly superior to CNT and graphene cellular materials with a similar density. Furthermore, pseudocapacitance-active functional groups are introduced into the new nanoporous graphene monolith as an electrode material in electrochemical capacitors. Surprisingly, the electrode of 3D mesoporous graphene has a specific capacitance of 303 F g(-1) and maintains over 98% retention after 10 000 cycles, belonging to the list for the best carbon-based active materials. The macroscopic mesoporous graphene monolith suggests the great potential as an electrode for supercapacitors in energy storage areas.

  14. Thermoresponsive ketoprofen-imprinted monolith prepared in ionic liquid.

    PubMed

    Sun, Xuan; Zhao, Chun-Yan; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

    2014-09-01

    A thermoresponsive imprinted monolith with the ability of molecular recognition for ketoprofen was prepared for the first time. The smart monolith was synthesized in a stainless steel column using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers, which can form interpolymer complexation to restrict access of the analyte to the imprinted networks at low temperatures. To avoid a high back pressure of the column derived from neat dimethyl sulfoxide (DMSO) as a porogenic solvent that is needed to solve polar AMPS, an ionic liquid, [BMIM]BF4, was introduced into the pre-polymerization mixture. The molecular recognition ability towards ketoprofen of the resulting thermoresponsive molecularly imprinted polymer (MIP) monolith displayed significant dependence on temperature compared with a non-imprinted column (NIP), and the greatest imprinting factor was achieved at the transition temperature of 35 °C (above 10). Furthermore, the number of binding sites of the smart MIP monolith at 35 °C was about 76 times as large as that at 25 °C. In addition, Freundlich analyses indicated that the thermoresponsive MIP monolith had homogeneous affinity sites at both 25 and 35 °C with heterogeneity index 0.9251 and 0.9851, respectively.

  15. Continuous vs. discrete models of nonadiabatic monolith catalysts

    SciTech Connect

    Groppi, G.; Tronconi, E.

    1996-08-01

    Monolith catalysts are widely applied for clean up of waste gases [catalytic mufflers, volatile organic compound (VOC) incinerators, reactors for selective catalytic reduction (SCR) of NO{sub x} by NH{sub 3}] in view of their unique combination of low-pressure drops and high gas-solid interfacial areas. The crucial point in continuous heat-transfer models is the evaluation of the effective thermal conductivity coefficients, which are functions both of the physical properties of the two phases and of the monolith geometry. In this work a novel expression for calculation of the radial effective conductivity is derived. The physical consistency of the steady-state continuous model implementing such an expression is then analyzed by comparison with a discrete monolith model. In spite of the just-mentioned limitations, discrete models have been partially validated in the literature against experimental temperature profiles in heated monoliths; thus, they can be regarded as a standard in evaluating the adequacy of the continuum approach. The reference problem of pure heat transfer with constant temperature of the external monolith wall is investigated for these purposes.

  16. Surfactant-Bound Monolithic Columns for Capillary Electrochromatography

    PubMed Central

    Gu, Congying; He, Jun; Jia, Jinping; Fang, Nenghu; Shamsi, Shahab A.

    2010-01-01

    A novel anionic surfactant bound monolithic stationary phase based on 11-acrylaminoundecanoic acid (AAUA) is designed for capillary electrochromatography (CEC). The monolith possessing bonded undecanoyl groups (hydrophobic sites) and carboxyl groups (weak cationic ion-exchange sites) was evaluated as a mixed-mode stationary phase in CEC for the separation of neutral and polar solutes. Using a multivariate D-optimal design the composition of the polymerization mixture was modeled and optimized with five alkylbenzenes (ABs) and seven alkyl phenyl ketones (APKs) as test solutes. The D-optimal design indicates a strong dependence of electrochromatographic parameters on the concentration of AAUA monomer and porogen (water) in the polymerization mixture. A difference of 6%, 8% and 13% RSD between the predicted and the experimental values in terms of efficiency, resolution, and retention time, respectively, indeed confirmed that the proposed approach is practical. The physical (i.e., morphology, porosity and permeability) and chromatographic properties of the monolithic columns were thoroughly investigated. With the optimized monolithic column, high efficiency separation of N-methylcarbamates (NMCs) pesticides and positional isomers was successfully achieved. It appears that this type of mixed-mode monolith (containing both chargeable and hydrophobic sites) may have a great potential as a new generation of CEC stationary phase. PMID:19885887

  17. Edge chipping and flexural resistance of monolithic ceramics☆

    PubMed Central

    Zhang, Yu; Lee, James J.-W.; Srikanth, Ramanathan; Lawn, Brian R.

    2014-01-01

    Objective Test the hypothesis that monolithic ceramics can be developed with combined esthetics and superior fracture resistance to circumvent processing and performance drawbacks of traditional all-ceramic crowns and fixed-dental-prostheses consisting of a hard and strong core with an esthetic porcelain veneer. Specifically, to demonstrate that monolithic prostheses can be produced with a much reduced susceptibility to fracture. Methods Protocols were applied for quantifying resistance to chipping as well as resistance to flexural failure in two classes of dental ceramic, microstructurally-modified zirconias and lithium disilicate glass–ceramics. A sharp indenter was used to induce chips near the edges of flat-layer specimens, and the results compared with predictions from a critical load equation. The critical loads required to produce cementation surface failure in monolithic specimens bonded to dentin were computed from established flexural strength relations and the predictions validated with experimental data. Results Monolithic zirconias have superior chipping and flexural fracture resistance relative to their veneered counterparts. While they have superior esthetics, glass–ceramics exhibit lower strength but higher chip fracture resistance relative to porcelain-veneered zirconias. Significance The study suggests a promising future for new and improved monolithic ceramic restorations, with combined durability and acceptable esthetics. PMID:24139756

  18. Carbon dioxide sequestration via olivine carbonation: Examining the formation of reaction products

    NASA Astrophysics Data System (ADS)

    King, H. E.; Plümper, O.; Putnis, A.

    2009-04-01

    Due to its abundance and natural ability to sequester CO2, olivine has been proposed as one mineral that could be used in the control of CO2 emissions into the atmosphere (Metz, 2005). Large scale peridotite deposits found in locations such as the Western Gneiss Region in Norway could provide in-situ sites for sequestration or the raw materials for ex-situ mineral carbonation. Determining the conditions under which magnesite (MgCO3) forms most efficiently is crucial to conduct a cost effective process. Understanding the development of secondary minerals is particularly important for in-situ methods as these phases can form passivating layers and affect the host rock porosity. The final solution of flow-through experiments conducted at alkaline pH have been shown to be supersaturated with respect to talc and chrysotile (Giammer et al., 2005), although these phases were not found to have precipitated the formation of a passivating, amorphous silica layer has been observed on reacted olivine surfaces (Bearat et al., 2006). By studying magnesite and other products produced during the carbonation of olivine within Teflon lined steel autoclaves we have begun to form a more comprehensive understanding of how these reactions would proceed during sequestration processes. We have performed batch experiments using carbonated saline solutions in the presence of air or gaseous CO2 from 80 to 200 ˚ C. X-ray powder diffraction was used to identify magnesite within the reaction products. Crystals of magnesite up to 20 m in diameter can be observed on olivine grain surfaces with scanning electron microscopy. Secondary reaction products formed a platy layer on olivine surfaces in reactions above 160 ˚ C and below pH 12. Energy dispersive X-ray analysis of the platy layer revealed an increase in Fe concentration. The macroscopically observable red colouration of the reaction products and Raman spectroscopy indicate that hematite is present in these layers. For experiments with

  19. The big fat LARS - a LArge Reservoir Simulator for hydrate formation and gas production

    NASA Astrophysics Data System (ADS)

    Beeskow-Strauch, Bettina; Spangenberg, Erik; Schicks, Judith M.; Giese, Ronny; Luzi-Helbing, Manja; Priegnitz, Mike; Klump, Jens; Thaler, Jan; Abendroth, Sven

    2013-04-01

    differences between gaseous and dissolved methane (Zimmer et al., 2011). Gas hydrate is formed using a confined pressure of 12-15 MPa and a fluid pressure of 8-11 MPa with a set temperature of 275 K. The duration of the formation process depends on the required hydrate saturation and is usually in a range of several weeks. The subsequent decomposition experiments aiming at testing innovative production scenarios such as the application of a borehole tool for thermal stimulation of hydrate via catalytic oxidation of methane within an autothermal catalytic reactor (Schicks et al. 2011). Furthermore, experiments on hydrate decomposition via pressure reduction are performed to mimic realistic scenarios such as found during the production test in Mallik (Yasuda and Dallimore, 2007). In the near future it is planned to scale up existing results on CH4-CO2 exchange efficiency (e.g. Strauch and Schicks, 2012) by feeding CO2 to the hydrate reservoir. All experiments are due to the gain of high-resolution spatial and temporal data predestined as a base for numerical modeling. References Schicks, J. M., Spangenberg, E., Giese, R., Steinhauer, B., Klump, J., Luzi, M., 2011. Energies, 4, 1, 151-172. Zimmer, M., Erzinger, J., Kujawa, C., 2011. Int. J. of Greenhouse Gas Control, 5, 4, 995-1001. Yasuda, M., Dallimore, S. J., 2007. Jpn. Assoc. Pet. Technol., 72, 603-607. Beeskow-Strauch, B., Schicks, J.M., 2012. Energies, 5, 420-437.

  20. The dam replacing gene product enhances Neisseria gonorrhoeae FA1090 viability and biofilm formation.

    PubMed

    Kwiatek, Agnieszka; Bacal, Pawel; Wasiluk, Adrian; Trybunko, Anastasiya; Adamczyk-Poplawska, Monika

    2014-01-01

    Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, possess drg (dam replacing gene) inserted in the leuS/dam locus. The drg locus in Neisseria gonorrhoeae FA1090 has a lower GC-pairs content (40.5%) compared to the whole genome of N. gonorrhoeae FA1090 (52%). The gonococcal drg gene encodes a DNA endonuclease Drg, with GmeATC specificity. Disruption of drg or insertion of the dam gene in gonococcal genome changes the level of expression of genes as shown by transcriptome analysis. For the drg-deficient N. gonorrhoeae mutant, a total of 195 (8.94% of the total gene pool) genes exhibited an altered expression compared to the wt strain by at least 1.5 fold. In dam-expressing N. gonorrhoeae mutant, the expression of 240 genes (11% of total genes) was deregulated. Most of these deregulated genes were involved in translation, DNA repair, membrane biogenesis and energy production as shown by cluster of orthologous group analysis. In vivo, the inactivation of drg gene causes the decrease of the number of live neisserial cells and long lag phase of growth. The insertion of dam gene instead of drg locus restores cell viability. We have also shown that presence of the drg gene product is important for N. gonorrhoeae FA1090 in adhesion, including human epithelial cells, and biofilm formation. Biofilm produced by drg-deficient strain is formed by more dispersed cells, compared to this one formed by parental strain as shown by scanning electron and confocal microscopy. Also adherence assays show a significantly smaller biomass of formed biofilm (OD570 = 0.242 ± 0.038) for drg-deficient strain, compared to wild-type strain (OD570 = 0.378 ± 0.057). Dam-expressing gonococcal cells produce slightly weaker biofilm with cells embedded in an extracellular matrix. This strain has also a five times reduced ability for adhesion to human epithelial cells. In this context, the presence of Drg is more advantageous for N. gonorrhoeae biology than

  1. The dam replacing gene product enhances Neisseria gonorrhoeae FA1090 viability and biofilm formation

    PubMed Central

    Kwiatek, Agnieszka; Bacal, Pawel; Wasiluk, Adrian; Trybunko, Anastasiya; Adamczyk-Poplawska, Monika

    2014-01-01

    Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, possess drg (dam replacing gene) inserted in the leuS/dam locus. The drg locus in Neisseria gonorrhoeae FA1090 has a lower GC-pairs content (40.5%) compared to the whole genome of N. gonorrhoeae FA1090 (52%). The gonococcal drg gene encodes a DNA endonuclease Drg, with GmeATC specificity. Disruption of drg or insertion of the dam gene in gonococcal genome changes the level of expression of genes as shown by transcriptome analysis. For the drg-deficient N. gonorrhoeae mutant, a total of 195 (8.94% of the total gene pool) genes exhibited an altered expression compared to the wt strain by at least 1.5 fold. In dam-expressing N. gonorrhoeae mutant, the expression of 240 genes (11% of total genes) was deregulated. Most of these deregulated genes were involved in translation, DNA repair, membrane biogenesis and energy production as shown by cluster of orthologous group analysis. In vivo, the inactivation of drg gene causes the decrease of the number of live neisserial cells and long lag phase of growth. The insertion of dam gene instead of drg locus restores cell viability. We have also shown that presence of the drg gene product is important for N. gonorrhoeae FA1090 in adhesion, including human epithelial cells, and biofilm formation. Biofilm produced by drg-deficient strain is formed by more dispersed cells, compared to this one formed by parental strain as shown by scanning electron and confocal microscopy. Also adherence assays show a significantly smaller biomass of formed biofilm (OD570 = 0.242 ± 0.038) for drg-deficient strain, compared to wild-type strain (OD570 = 0.378 ± 0.057). Dam-expressing gonococcal cells produce slightly weaker biofilm with cells embedded in an extracellular matrix. This strain has also a five times reduced ability for adhesion to human epithelial cells. In this context, the presence of Drg is more advantageous for N. gonorrhoeae biology than

  2. Fabrication of the LSST monolithic primary-tertiary mirror

    NASA Astrophysics Data System (ADS)

    Tuell, Michael T.; Martin, Hubert M.; Burge, James H.; Ketelsen, Dean A.; Law, Kevin; Gressler, William J.; Zhao, Chunyu

    2012-09-01

    As previously reported (at the SPIE Astronomical Instrumentation conference of 2010 in San Diego1), the Large Synoptic Survey Telescope (LSST) utilizes a three-mirror design in which the primary (M1) and tertiary (M3) mirrors are two concentric aspheric surfaces on one monolithic substrate. The substrate material is Ohara E6 borosilicate glass, in a honeycomb sandwich configuration, currently in production at The University of Arizona’s Steward Observatory Mirror Lab. We will provide an update to the status of the mirrors and metrology systems, which have advanced from concepts to hardware in the past two years. In addition to the normal requirements for smooth surfaces of the appropriate prescriptions, the alignment of the two surfaces must be accurately measured and controlled in the production lab, reducing the degrees of freedom needed to be controlled in the telescope. The surface specification is described as a structure function, related to seeing in excellent conditions. Both the pointing and centration of the two optical axes are important parameters, in addition to the axial spacing of the two vertices. This paper details the manufacturing process and metrology systems for each surface, including the alignment of the two surfaces. M1 is a hyperboloid and can utilize a standard Offner null corrector, whereas M3 is an oblate ellipsoid, so it has positive spherical aberration. The null corrector is a phase-etched computer-generated hologram (CGH) between the mirror surface and the center-of-curvature. Laser trackers are relied upon to measure the alignment and spacing as well as rough-surface metrology during looseabrasive grinding.

  3. Submerged conidiation and product formation by Aspergillus niger at low specific growth rates are affected in aerial developmental mutants.

    PubMed

    Jørgensen, Thomas R; Nielsen, Kristian F; Arentshorst, Mark; Park, Joohae; van den Hondel, Cees A; Frisvad, Jens C; Ram, Arthur F

    2011-08-01

    Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (ΔfwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B(2), B(4), and B(6) were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ΔfwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic

  4. Color-Center Production and Formation in Electron-Irradiated Magnesium Aluminate Spinel and Ceria

    DOE PAGES

    Costantini, Jean-Marc; Lelong, Gerald; Guillaumet, Maxime; ...

    2016-06-20

    Single crystals of magnesium aluminate spinel (MgAl2O4) with (100) or (110) orientations and cerium dioxide or ceria (CeO2) were irradiated by 1.0-MeV and 2.5-MeV electrons in a high fluence range. Point-defect production was studied by off-line UV-visible optical spectroscopy after irradiation. For spinel, regardless of both crystal orientation and electron energy, two characteristic broad bands centered at photon energies of 5.4 eV and 4.9 eV were assigned to F and F+ centers (neutral and singly-ionized oxygen vacancies), respectively, on the basis of available literature data. No clear differences in colour-centre formation were observed for the two crystal orientations. Using calculationsmore » of displacement cross sections by elastic collisions, these results are consistent with a very large threshold displacement energy (200 eV) for oxygen atoms at RT. A third very broad band centered at 3.7 eV might be attributed either to an oxygen hole center (V-type center) or an F2 dimer center (oxygen di-vacancy). The onset of recovery of these color centers took place at 200°C with almost full bleaching at 600°C. Activation energies (~0.3-0.4 eV) for defect recovery were deduced from the isochronal annealing data by using a first-order kinetics analysis. For ceria, a sub band-gap absorption feature peaked at ~3.1 eV was recorded for 2.5-MeV electron irradiation only. Assuming a ballistic process, we suggest that the latter defect might result from cerium atom displacement on the basis of computed cross sections.« less

  5. Color-Center Production and Formation in Electron-Irradiated Magnesium Aluminate Spinel and Ceria

    SciTech Connect

    Costantini, Jean-Marc; Lelong, Gerald; Guillaumet, Maxime; Weber, William J.; Takaki, Seiya; Yasuda, Kazuhiro

    2016-06-20

    Single crystals of magnesium aluminate spinel (MgAl2O4) with (100) or (110) orientations and cerium dioxide or ceria (CeO2) were irradiated by 1.0-MeV and 2.5-MeV electrons in a high fluence range. Point-defect production was studied by off-line UV-visible optical spectroscopy after irradiation. For spinel, regardless of both crystal orientation and electron energy, two characteristic broad bands centered at photon energies of 5.4 eV and 4.9 eV were assigned to F and F+ centers (neutral and singly-ionized oxygen vacancies), respectively, on the basis of available literature data. No clear differences in colour-centre formation were observed for the two crystal orientations. Using calculations of displacement cross sections by elastic collisions, these results are consistent with a very large threshold displacement energy (200 eV) for oxygen atoms at RT. A third very broad band centered at 3.7 eV might be attributed either to an oxygen hole center (V-type center) or an F2 dimer center (oxygen di-vacancy). The onset of recovery of these color centers took place at 200°C with almost full bleaching at 600°C. Activation energies (~0.3-0.4 eV) for defect recovery were deduced from the isochronal annealing data by using a first-order kinetics analysis. For ceria, a sub band-gap absorption feature peaked at ~3.1 eV was recorded for 2.5-MeV electron irradiation only. Assuming a ballistic process, we suggest that the latter defect might result from cerium atom displacement on the basis of computed cross sections.

  6. Biofilm Formation and Quorum-Sensing-Molecule Production by Clinical Isolates of Serratia liquefaciens

    PubMed Central

    Remuzgo-Martínez, Sara; Lázaro-Díez, María; Mayer, Celia; Aranzamendi-Zaldumbide, Maitane; Padilla, Daniel; Calvo, Jorge; Marco, Francesc; Martínez-Martínez, Luis; Icardo, José Manuel; Otero, Ana

    2015-01-01

    Serratia spp. are opportunistic human pathogens responsible for an increasing number of nosocomial infections. However, little is known about the virulence factors and regulatory circuits that may enhance the establishment and long-term survival of Serratia liquefaciens in the hospital environment. In this study, two reporter strains, Chromobacterium violaceum CV026 and VIR24, and high-resolution triple-quadrupole liquid chromatography–mass spectrometry (LC-MS) were used to detect and to quantify N-acyl-homoserine lactone (AHL) quorum-sensing signals in 20 S. liquefaciens strains isolated from clinical samples. Only four of the strains produced sufficient amounts of AHLs to activate the sensors. Investigation of two of the positive strains by high-performance liquid chromatography (HPLC)-MS confirmed the presence of significant amounts of short-acyl-chain AHLs (N-butyryl-l-homoserine lactone [C4-HSL] and N-hexanoyl-l-homoserine lactone [C6-HSL]) in both strains, which exhibited a complex and strain-specific signal profile that included minor amounts of other short-acyl-chain AHLs (N-octanoyl-l-homoserine lactone [C8-HSL] and N-3-oxohexanoyl-l-homoserine lactone [OC6-HSL]) and long-acyl-chain (C10, C12, and C14) AHLs. No correlation between biofilm formation and the production of large amounts of AHLs could be established. Fimbria-like structures were observed by transmission electron microscopy, and the presence of the type 1 fimbrial adhesin gene fimH in all strains was confirmed by PCR. The ability of S. liquefaciens to adhere to abiotic surfaces and to form biofilms likely contributes to its persistence in the hospital environment, increasing the probability of causing nosocomial infections. Therefore, a better understanding of the adherence properties of this species will provide greater insights into the diseases it causes. PMID:25746999

  7. Fabrication and characterization of nanotemplated carbon monolithic material.

    PubMed

    He, Xiaoyun; Nesterenko, Ekaterina P; Nesterenko, Pavel N; Brabazon, Dermot; Zhou, Lin; Glennon, Jeremy D; Luong, John H T; Paull, Brett

    2013-09-11

    A novel hierarchical nanotemplated carbon monolithic rod (NTCM) was prepared using a novel facile nanotemplating approach. The NTCM was obtained using C60-fullerene modified silica gels as hard templates, which were embedded in a phenolic resin containing a metal catalyst for localized graphitization, followed by bulk carbonization, and template and catalyst removal. TEM, SEM, and BET measurements revealed that NTCM possessed an integrated open hierarchical porous structure, with a trimodal pore distribution. This porous material also possessed a high mesopore volume and narrow mesopore size distribution. During the course of carbonization, the C60 conjugated to aminated silica was partly decomposed, leading to the formation of micropores. The Raman signature of NTCM was very similar to that of multiwalled carbon nanotubes as exemplified by three major peaks as commonly observed for other carbon materials, i.e., the sp3 and sp2 carbon phases coexisted in the sample. Surface area measurements were obtained using both nitrogen adsorption/desorption isotherms (BET) and with a methylene blue binding assay, with BET results showing the NTCM material possessed an average specific surface area of 435 m2 g(-1), compared to an area of 372 m2 g(-1) obtained using the methylene blue assay. Electrochemical studies using NTCM modified glassy carbon or boron doped diamond (BDD) electrodes displayed quasi-reversible oxidation/reduction with ferricyanide. In addition, the BDD electrode modified with NTCM was able to detect hydrogen peroxide with a detection limit of below 300 nM, whereas the pristine BDD electrode was not responsive to this target compound.

  8. GaAs monolithic R.F. modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  9. Effect of roasting time of buckwheat groats on the formation of Maillard reaction products and antioxidant capacity.

    PubMed

    Małgorzata, Wronkowska; Konrad, Piskuła Mariusz; Zieliński, Henryk

    2016-04-01

    Changes in the formation of Maillard reaction products and antioxidant capacity of buckwheat, induced by roasting at 160 °C for 30, 40 and 50 min, were evaluated in the study. Furozine, was detected after roasting, in all buckwheat samples. Increase of FIC, the presence of significant amounts of CML and enhanced browning were observed, along with increasing times of roasting. The formation of acrylamide in the obtained buckwheat products was also significantly connected with the time of roasting. A significant degradation was observed in natural antioxidants, as affected by heat treatment time. The colour parameter changed significantly with the increasing of roasting time. Overall, 30min of roasting was beneficial from a nutritional point of view for the obtained buckwheat product.

  10. Influence of reaction time and temperature on product formation and characteristics associated with the hydrothermal carbonization of cellulose.

    PubMed

    Lu, Xiaowei; Pellechia, Perry J; Flora, Joseph R V; Berge, Nicole D

    2013-06-01

    Studies have demonstrated that hydrothermal carbonization of biomass and waste streams results in the formation of beneficial materials/resources with minimal greenhouse gas production. Data necessary to understand how critical process conditions influence carbonization mechanisms, product formation, and associated environmental implications are currently lacking. The purpose of this work is to hydrothermally carbonize cellulose at different temperatures and to systematically sample over a 96-h period to determine how changes in reaction temperature influence product evolution. Understanding cellulose carbonization will provide insight to carbonization of cellulosic biomass and waste materials. Results from batch experiments indicate that the majority of cellulose conversion occurs between the first 0.5-4h, and faster conversion occurs at higher temperatures. Data collected over time suggest cellulose solubilization occurs prior to conversion. The composition of solids recovered after 96h is similar at all temperatures, consisting primarily of sp(2) carbons (furanic and aromatic groups) and alkyl groups.

  11. A very low noise monolithic Horizontal accelerometer.

    NASA Astrophysics Data System (ADS)

    Bertolini, Alessandro; Takamori, Akiteru; Cella, Giancarlo; Fidecaro, Francesco; Francesconi, Mario; Desalvo, Riccardo; Sannibale, Virginio

    2000-04-01

    We present a new low noise, low frequency, horizontal accelerometer. The mechanical design and the machining process aim to improve the sensitivity in the frequency region between 0.01 and 1 Hz, where metal internal friction and thermal elastic effects become critical. The accelerometer mechanics is shaped as a small folded pendulum in order to obtain a very low resonant frequency and low mechanical losses. A folded pendulum is essentially a mass suspended on one side by a simple pendulum and on the other by an inverted pendulum working antagonistically. The straight pendulum positive gravitational spring constant is balanced by the inverted pendulum’s negative one; by changing the center of mass position one can lower arbitrarily the resonant frequency. The only dissipation is in the anelasticity of the mechanical flex joint and in the readout/actuation system. If the spring constant is minimised, the mechanical losses are minimal. The monolithic design of the accelerometer eliminates the stick-and-slip friction localised in the flexure clamps. Low stiffness, 10 micron thick flex joints are achieved by EDM and electropolishing. The instrument is equipped with a low capacitance position sensor; the signal from the sensor is filtered by a PID controller and fed back to the mass through capacitive force actuator for feedback closed-loop operation. The sensor noise matches the expected thermal noise performances, 10-12 m/√Hz , with measuring range of a few microns. The expected sensitivity, less than 10-11 m/ s^2 / √Hz around 150 mHz, is a factor 30 below the state of the art limit. This accelerometer was designed to be integrated in the active control of the LIGO II mirror seismic isolators.

  12. Monolithic Solid Oxide Fuel Cell development

    NASA Technical Reports Server (NTRS)

    Myles, K. M.; Mcpheeters, C. C.

    1989-01-01

    The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source.

  13. Monolithic Solid Oxide Fuel Cell development

    NASA Astrophysics Data System (ADS)

    Myles, K. M.; McPheeters, C. C.

    1989-12-01

    The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source.

  14. Low cost high efficiency GaAs monolithic RF module for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Petersen, W. C.; Siu, D. P.; Cook, H. F.

    1991-01-01

    Low cost high performance (5 Watts output) 406 MHz beacons are urgently needed to realize the maximum utilization of the Search and Rescue Satellite-Aided Tracking (SARSAT) system spearheaded in the U.S. by NASA. Although current technology can produce beacons meeting the output power requirement, power consumption is high due to the low efficiency of available transmitters. Field performance is currently unsatisfactory due to the lack of safe and reliable high density batteries capable of operation at -40 C. Low cost production is also a crucial but elusive requirement for the ultimate wide scale utilization of this system. Microwave Monolithics Incorporated (MMInc.) has proposed to make both the technical and cost goals for the SARSAT beacon attainable by developing a monolithic GaAs chip set for the RF module. This chip set consists of a high efficiency power amplifier and a bi-phase modulator. In addition to implementing the RF module in Monolithic Microwave Integrated Circuit (MMIC) form to minimize ultimate production costs, the power amplifier has a power-added efficiency nearly twice that attained with current commercial technology. A distress beacon built using this RF module chip set will be significantly smaller in size and lighter in weight due to a smaller battery requirement, since the 406 MHz signal source and the digital controller have far lower power consumption compared to the 5 watt power amplifier. All the program tasks have been successfully completed. The GaAs MMIC RF module chip set has been designed to be compatible with the present 406 MHz signal source and digital controller. A complete high performance low cost SARSAT beacon can be realized with only additional minor iteration and systems integration.

  15. Thermal stability of plant sterols and formation of their oxidation products in vegetable oils and margarines upon controlled heating.

    PubMed

    Lin, Yuguang; Knol, Diny; Valk, Iris; van Andel, Vincent; Friedrichs, Silvia; Lütjohann, Dieter; Hrncirik, Karel; Trautwein, Elke A

    2017-02-02

    Fat-based products like vegetable oils and margarines are commonly used for cooking, which may enhance oxidation of plant sterols (PS) present therein, leading to the formation of PS oxidation products (POP). The present study aims to assess the kinetics of POP formation in six different fat-based products. Vegetable oils and margarines without and with added PS (7.5-7.6% w/w) in esterified form were heated in a Petri-dish at temperatures of 150, 180 and 210°C for 8, 12 and 16min. PS and POP were analysed using GC-FID and GC-MS-SIM, respectively. Increasing PS content, temperature and heating time led to higher POP formation in all tested fat-based products. PS (either naturally occurring or added) in margarines were less susceptible to oxidation as compared to PS in vegetable oils. The susceptibility of sitosterol to oxidation was about 20% lower than that of campesterol under all the applied experimental conditions. During heating, the relative abundance of 7-keto-PS (expressed as% of total POP) decreased in all the fat-based products regardless of their PS contents, which was accompanied by an increase in the relative abundance of 7-OH-PS and 5,6-epoxy-PS, while PS-triols were fairly unchanged. In conclusion, heating time, temperature, initial PS content and the matrix of the fat-based products (vegetable oil vs. margarine) showed distinct effects on POP formation and composition of individual POP formed.

  16. Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel

    SciTech Connect

    Karen L. Shropshire

    2008-04-01

    Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

  17. Nickel sulfide formation at low temperature: initial precipitates, solubility and transformation products

    EPA Science Inventory

    The formation of nickel sulfides has been examined experimentally over the temperature range from 25 to 60°C. At all conditions studied, hexagonal (α-NiS) was the initial precipitate from solution containing Ni2+ and dissolved sulfide. The formation of millerite (β- NiS, rhombo...

  18. Factors affecting the formation of nitrogenous disinfection by-products during chlorination of aspartic acid in drinking water.

    PubMed

    Chen, Wei; Liu, Zhigang; Tao, Hui; Xu, Hang; Gu, Yanmei; Chen, Zhaolin; Yu, Jingjing

    2017-01-01

    The formation of emerging nitrogenous disinfection by-products (N-DBPs) from the chlorination of aspartic acid (Asp) was investigated. The yield of dichloroacetonitrile (DCAN) was higher than other N-DBPs, such as dichloroacetamide(DCAcAm) and chloropicrin (TCNM) during the chlorination of Asp. The formation of DCAN, DCAcAm, and TCNM all showed a trend of first increasing and then decreasing during the chlorination of Asp with increasing contact time. The dosage of chlorine had an impact on the formation of DCAN, DCAcAm, and TCNM. The highest yields of DCAN and DCAcAm appeared when the Cl2/Asp molar ratio was about 20, the yield of TCNM increased with increasing the Cl2/Asp molar ratio from 5 to 30 and TCNM was not produced when the ratio was less than 5. Cyanogen chloride (CNCl) was detected when the Cl2/Asp molar ratio was lower than 5. N-DBPs formation was influenced by pH. DCAN formation increased with increasing pH from 5 to 6 and then decreased with increasing pH from 6 to 9, but DCAcAm and TCNM increased with increasing pH from 5 to 8 and then decreased. Higher temperatures reduced the formation of DCAN and DCAcAm, but increased TCNM formation. DCAN and DCAcAm formation decreased, and relatively stable TCNM formation increased, with increasing free chlorine contact time during chloramination. N-nitrosodimethylamine (NDMA) was produced during chloramination of Asp and increased with prolonged chloramination contact time. The presence of bromide ions enhanced the yields of haloacetonitriles and shifted N-DBPs to more brominated species.

  19. A Possible Astronomically Aligned Monolith at Gardom's Edge

    NASA Astrophysics Data System (ADS)

    Brown, Daniel; Alder, Andy; Bemand, Elizabeth

    2015-05-01

    A unique triangular shaped monolith located within the Peak District National Park at Gardom's Edge could be intentionally astronomically aligned. It is set within a landscape rich in late Neolithic and Bronze Age remains. We show that the stone is most likely in its original orientation owing to its clear signs of erosion and associated to the time period of the late Neolithic. It is tilted towards south and its north side slopes at an angle equal to the maximum altitude of the Sun at mid-summer. This alignment emphasizes the changing declinations of the Sun during the seasons as well as giving an indication of mid-summers day. This functionality is achieved by an impressive display of light and shadow on the north facing side of the monolith. Together with other monuments in the close vicinity the monolith would have represented an ideal marker or social arena for seasonal gatherings for the otherwise dispersed small communities.

  20. Wide band monolithic SAW convolver for asynchronous communications

    NASA Astrophysics Data System (ADS)

    Toplicar, J. R.

    The rapid acquisition of code synchronization without prior knowledge of time of arrival of a received signal is a key problem in secure spread spectrum communications. Monolithic SAW convolvers used as programmable matched filters provide a low-cost solution to this rapid synchronization problem. In this paper a description is presented of techniques for decoding binary coded signals using monolithic SAW convolvers. The principles of operation of the convolver and methods of obtaining unambiguous code synchronization are discussed. Key monolithic convolver design parameters as well as the impact of design on achievable processing gain, dynamic range, suppression of spurious signals, size, and cost are described. Design and performance details are presented and compared with theoretical predictions and with com

  1. Plastic deformation of silicon nitride/boron nitride fibrous monoliths.

    SciTech Connect

    de Arellano-Lopez, A. R.; Lopez-Pombero, S.; Dominguez-Rodriguez, A.; Routbort, J. L.; Singh, D.; Goretta, K. C.; Energy Technology; Univ. de Sevilla

    2001-02-01

    High-temperature compressive creep of unidirectional Si{sub 3}N{sub 4}/BN fibrous monoliths has been investigated at 1300-1500 C in an inert atmosphere. The results were then compared to those for deformation of the Si{sub 3}N{sub 4} and BN base materials. Plasticity of the fibrous monoliths was limited to very low stresses when the Si{sub 3}N{sub 4} cells were oriented perpendicular to the stress axis because the BN cell boundaries failed, followed by failure of the Si{sub 3}N{sub 4} cells. In the fibrous monolith in which cells were oriented parallel to the stress axis, steady-state deformation controlled by deformation of the Si{sub 3}N{sub 4} cells was achieved.

  2. CHARACTERIZATION OF MONOLITHIC FUEL FOIL PROPERTIES AND BOND STRENGTH

    SciTech Connect

    D E Burkes; D D Keiser; D M Wachs; J S Larson; M D Chapple

    2007-03-01

    Understanding fuel foil mechanical properties, and fuel / cladding bond quality and strength in monolithic plates is an important area of investigation and quantification. Specifically, what constitutes an acceptable monolithic fuel – cladding bond, how are the properties of the bond measured and determined, and what is the impact of fabrication process or change in parameters on the level of bonding? Currently, non-bond areas are quantified employing ultrasonic determinations that are challenging to interpret and understand in terms of irradiation impact. Thus, determining mechanical properties of the fuel foil and what constitutes fuel / cladding non-bonds is essential to successful qualification of monolithic fuel plates. Capabilities and tests related to determination of these properties have been implemented at the INL and are discussed, along with preliminary results.

  3. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY_

    SciTech Connect

    G. A. Moore; F. J. Rice; N. E. Woolstenhulme; J-F. Jue; B. H. Park; S. E. Steffler; N. P. Hallinan; M. D. Chapple; M. C. Marshall; B. L. Mackowiak; C. R. Clark; B. H. Rabin

    2009-11-01

    Full-size/prototypic U10Mo monolithic fuel-foils and aluminum clad fuel plates are being developed at the Idaho National Laboratory’s (INL) Materials and Fuels Complex (MFC). These efforts are focused on realizing Low Enriched Uranium (LEU) high density monolithic fuel plates for use in High Performance Research and Test Reactors. The U10Mo fuel foils under development afford a fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. An overview is provided of the ongoing monolithic UMo fuel development effort, including application of a zirconium barrier layer on fuel foils, fabrication scale-up efforts, and development of complex/graded fuel foils. Fuel plate clad bonding processes to be discussed include: Hot Isostatic Pressing (HIP) and Friction Bonding (FB).

  4. Tooth-colored CAD/CAM monolithic restorations.

    PubMed

    Reich, S

    2015-01-01

    A monolithic restoration (also known as a full contour restoration) is one that is manufactured from a single material for the fully anatomic replacement of lost tooth structure. Additional staining (followed by glaze firing if ceramic materials are used) may be performed to enhance the appearance of the restoration. For decades, monolithic restoration has been the standard for inlay and partial crown restorations manufactured by both pressing and computer-aided design and manufacturing (CAD/CAM) techniques. A limited selection of monolithic materials is now available for dental crown and bridge restorations. The IDS (2015) provided an opportunity to learn about and evaluate current trends in this field. In addition to new developments, established materials are also mentioned in this article to complete the picture. In line with the strategic focus of the IJCD, the focus here is naturally on CAD/CAM materials.

  5. Cerec anterior crowns: restorative options with monolithic ceramic materials.

    PubMed

    Reich, Sven; Fiedlar, Kurt

    2013-01-01

    The aim of this article is to discuss the different types of monolithic ceramic crowns that can be placed on anterior teeth with existing shoulder preparations. Anterior crowns were indicated for the teeth 12 to 22 in the present case. The patient, a 65-year-old male, had received all-ceramic crowns 20 years earlier, which had started to develop cracks and palatal fractures over the last few years. The patient's teeth were prepared and four sets of crowns were fabricated using different monolithic ceramic materials: IPS e.max CAD, Cerec Blocs C In, VITABLOCS Real Life, and ENAMIC. Both shade characterization and crystallization firing were performed on the monolithic lithium disilicate glass ceramic crowns. The silicate ceramic crowns received glaze firing alone. The crowns made of hybrid ceramic (ENAMIC) were treated with a polymer sealant.

  6. Effects of lead(II) on the extracellular polysaccharide (EPS) production and colony formation of cultured Microcystis aeruginosa.

    PubMed

    Bi, Xiang-dong; Zhang, Shu-lin; Dai, Wei; Xing, Ke-zhing; Yang, Fan

    2013-01-01

    To investigate the effects of lead(II) on the production of extracellular polysaccharides (EPS), including bound extracellular polysaccharides (bEPS) and soluble extracellular polysaccharides (sEPS), and the colony formation of Microcystis aeruginosa, cultures of M. aeruginosa were exposed to four concentrations (5.0, 10.0, 20.0 and 40.0 mg/L) of lead(II) for 10 d under controlled laboratory conditions. The results showed that 5.0 and 10.0 mg/L lead(II) stimulated M. aeruginosa growth throughout the experiment while 20.0 and 40.0 mg/L lead(II) inhibited M. aeruginosa growth in the first 2 d exposure and then stimulated it. As compared to the control group, significant increases in the bEPS and sEPS production were observed in 20.0 and 40.0 mg/L lead(II) treatments (P < 0.05). Large colony formations were not observed throughout the experiment. However, four tested concentrations of lead(II) could significantly promote the formation of small and middle colonies after 10 d exposure (P < 0.05), and 40.0 mg/L lead(II) had the best stimulatory effect. Lead(II) could stimulate bEPS production, which conversely promoted colony formation, suggesting that heavy metals might be contributing to the bloom-forming of M. aeruginosa in natural conditions.

  7. Peroxynitrite-induced oxidation and nitration products of guanine and 8-oxoguanine: structures and mechanisms of product formation.

    PubMed

    Niles, Jacquin C; Wishnok, John S; Tannenbaum, Steven R

    2006-03-01

    Peroxynitrite induces DNA base damage predominantly at guanine (G) and 8-oxoguanine (8-oxoG) nucleobases via oxidation reactions. Nitration products are also observed, consistent with the generation of radical intermediates that can recombine with the (.)NO(2) formed during peroxynitrite degradation. The neutral G radical, G(.), reacts with (.)NO(2) to yield 8-nitroguanine (8-nitroG) and 5-nitro-4-guanidinohydantoin (NI), while for 8-oxoG we have proposed a reactive guanidinylidene radical intermediate. The products generated during peroxynitrite-mediated 8-oxoG oxidation depend on oxidant flux, with dehydroguanidinohydantoin (DGh), 2,4,6-trioxo-[1,3,5]triazinane-1-carboxamidine (CAC) and NO(2)-DGh predominating at high fluxes and spiroiminodihydantoin (Sp), guanidinohydantoin (Gh) and 4-hydroxy-2,5-dioxo-imidazolidine-4-carboxylic acid (HICA) predominating at low fluxes. Both product sets are observed at intermediate fluxes. It is therefore important in model systems to ensure that the relative concentrations are well controlled to minimize competing reactions that may not be relevant in vivo. Increasingly sophisticated systems for modeling peroxynitrite production in vivo are being developed and these should help with predicting the products most likely to be formed in vivo. Together with the emerging information on the genotoxic and mutational characteristics of the individual oxidation products, it may be found that the extent of tissue damage, mutational spectra and, hence, cancer risk may change as a function of peroxynitrite fluxes as different product combinations predominate.

  8. Development of an affinity silica monolith containing human serum albumin for chiral separations.

    PubMed

    Mallik, Rangan; Hage, David S

    2008-04-14

    An affinity monolith based on silica and containing immobilized human serum albumin (HSA) was developed and evaluated in terms of its binding, efficiency and selectivity in chiral separations. The results were compared with data obtained for the same protein when used as a chiral stationary phase with HPLC-grade silica particles or a monolith based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA). The surface coverage of HSA in the silica monolith was similar to values obtained with silica particles and a GMA/EDMA monolith. However, the higher surface area of the silica monolith gave a material that contained 1.3-2.2-times more immobilized HSA per unit volume when compared to silica particles or a GMA/EDMA monolith. The retention, efficiency and resolving power of the HSA silica monolith were evaluated using two chiral analytes: d/l-tryptophan and R/S-warfarin. The separation of R- and S-ibuprofen was also considered. The HSA silica monolith gave higher retention and higher or comparable resolution and efficiency when compared with HSA columns that contained silica particles or a GMA/EDMA monolith. The silica monolith also gave lower back pressures and separation impedances than these other materials. It was concluded that silica monoliths can be valuable alternatives to silica particles or GMA/EDMA monoliths when used with immobilized HSA as a chiral stationary phase.

  9. Preparation of poly(γ-glutamic acid)/hydroxyapatite monolith via biomineralization for bone tissue engineering.

    PubMed

    Park, Sung-Bin; Hasegawa, Urara; van der Vlies, André J; Sung, Moon-Hee; Uyama, Hiroshi

    2014-01-01

    A hybrid monolith of poly(γ-glutamic acid) and hydroxyapatite (PGA/HAp monolith) was prepared via biomineralization and used as a macroporous cell scaffold in bone tissue engineering. The PGA monolith having a bimodal pore size distribution was used as a substrate to induce biomineralization. The PGA/HAp monolith was obtained by immersing the PGA monolith in simulated body fluid. Pretreatment with CaCl2 enhanced the apatite-forming ability of the PGA monolith. Murine osteoblastic MC3T3-E1 cells efficiently attached and proliferated on the PGA/HAp monolith. MTT assay showed that both the PGA and PGA/HAp monolith did not have apparent cytotoxicity. Moreover, the PGA and PGA/HAp monoliths adsorbed bone morphogenetic protein-2 (BMP-2) by electrostatic interaction which was slowly released in the medium during cell culture. The PGA/HAp monolith enhanced BMP-2 induced alkaline phosphatase activity compared to the PGA monolith and a polystyrene culture plate. Thus, these PGA/HAp monoliths may have potential in bone tissue engineering.

  10. Monolithic Microwave Integrated Circuit (MMIC) Frequency Doublers - 2nd Pass Correction

    DTIC Science & Technology

    2013-09-01

    Monolithic Microwave Integrated Circuit (MMIC) Frequency Doublers—2nd Pass Correction by John E. Penn ARL-TN-0580 September 2013...September 2013 Monolithic Microwave Integrated Circuit (MMIC) Frequency Doublers—2nd Pass Correction John E. Penn Sensors and Electron...COVERED (From - To) 4. TITLE AND SUBTITLE Monolithic Microwave Integrated Circuit (MMIC) Frequency Doublers–2nd Pass Correction 5a. CONTRACT NUMBER

  11. Structure formation of aerated concrete containing waste coal combustion products generated in the thermal vortex power units

    NASA Astrophysics Data System (ADS)

    Ivanov, A. I.; Stolboushkin, A. Yu; Temlyanstev, M. V.; Syromyasov, V. A.; Fomina, O. A.

    2016-10-01

    The results of fly ash research, generated in the process of waste coal combustion in the thermal vortex power units and used as an aggregate in aerated concrete, are provided. It is established that fly ash can be used in the production of cement or concrete with low loss on ignition (LOI). The permitted value of LOI in fly ash, affecting the structure formation and operational properties of aerated concrete, are defined. During non-autoclaved hardening of aerated concrete with fly ash aggregate and LOI not higher than 2%, the formation of acicular crystals of ettringite, reinforcing interporous partitions, takes place.

  12. Streptomycetes in micro-cultures: growth, production of secondary metabolites, and storage and retrieval in the 96-well format.

    PubMed

    Minas, W; Bailey, J E; Duetz, W

    2000-12-01

    Mycelium-forming Streptomyces strains were grown in one milliliter liquid micro-cultures in square deep-well microtiter plates. Growth was evaluated with respect to biomass formation and production of secondary metabolites which were found to be very similar in the micro-cultures, bioreactor, and shake flask cultivations, respectively. Despite repetitive sampling and extensive growth on the walls of the wells, no cross contamination occurred. Furthermore, we successfully employed cold storage at -20 degrees C of spore suspensions (in the 96-well format), directly prepared from cultures grown on agar in the microtitre plate. Cultures were retrieved by replicating aliquots from the frozen spore suspensions.

  13. The role of monolithic integration in advanced laser products

    NASA Astrophysics Data System (ADS)

    Marsh, John H.

    2006-02-01

    The design and performance of single-mode high-power (>100 mW) semiconductor lasers suitable for integration into large arrays are reported. In 830 nm lasers, quantum well intermixing (QWI) has been used to increase the bandgap of the waveguide in the facet region by 120 meV, and the catastrophic optical damage threshold of uncoated devices increased by a factor of >3 as a result. The passive waveguides are relatively cool, bringing high reliability, improving the single-mode waveguide stability and enabling high-temperature operation. Furthermore, the passive waveguides relax the cleaving and packaging alignment tolerances, giving a high yield process suitable for manufacture. A far-field reduction layer is included in the lasers giving a fast axis divergence of <20° FWHM. Arrays in which each emitter operates at several 100 mW, have excellent uniformity of laser parameters such as kink power, operating power and optical beam profile.

  14. Development of large-area monolithically integrated Silicon-Film photovoltaic modules. Annual subcontract report, 16 November 1991--31 December 1992

    SciTech Connect

    Rand, J.A.; Cotter, J.E.; Ingram, A.E.; Ruffins, T.R.; Shreve, K.P.; Hall, R.B.; Barnett, A.M.

    1993-06-01

    This report describes work to develop Silicon-Film{trademark} Product III into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product III structure is a thin (< 100-{mu}m) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achievable with the use of light trapping and a passivated back surface. The long-term goal for the product is a 1200-cm{sup 2}, 18%-efficient, monolithic array. The short-term objectives are to improve material quality and to fabricate 100 cm{sup 2} monolithically interconnected solar cell arrays. Low minority-carrier diffusion length in the silicon film and series resistance in the interconnected device structure are presently limiting device performance. Material quality is continually improving through reduced impurity contamination. Metallization schemes, such as a solder-dipped interconnection process, have been developed that will allow low-cost production processing and minimize R{sub s} effects. Test data for a nine-cell device (16 cm{sup 2}) indicated a V{sub oc} of 3.72 V. These first-reported monolithically interconnected multicrystalline silicon-on-ceramic devices show low shunt conductance (< 0.1 mA/cm{sup 2}) due to limited conduction through the ceramic and no process-related metallization shunts.

  15. Lectin-carbohydrate interactions on nanoporous gold monoliths.

    PubMed

    Tan, Yih Horng; Fujikawa, Kohki; Pornsuriyasak, Papapida; Alla, Allan J; Ganesh, N Vijaya; Demchenko, Alexei V; Stine, Keith J

    2013-07-01

    Monoliths of nanoporous gold (np-Au) were modified with self-assembled monolayers of octadecanethiol (C18-SH), 8-mercaptooctyl α-D-mannopyranoside (αMan-C8-SH), and 8-mercapto-3,6-dioxaoctanol (HO-PEG2-SH), and the loading was assessed using thermogravimetric analysis (TGA). Modification with mixed SAMs containing αMan-C8-SH (at a 0.20 mole fraction in the SAM forming solution) with either octanethiol or HO-PEG2-SH was also investigated. The np-Au monoliths modified with αMan-C8-SH bind the lectin Concanavalin A (Con A), and the additional mass due to bound protein was assessed using TGA analysis. A comparison of TGA traces measured before and after exposure of HO-PEG2-SH modified np-Au to Con A showed that the non-specific binding of Con A was minimal. In contrast, np-Au modified with octanethiol showed a significant mass loss due to non-specifically adsorbed Con A. A significant mass loss was also attributed to binding of Con A to bare np-Au monoliths. TGA revealed a mass loss due to the binding of Con A to np-Au monoliths modified with pure αMan-C8-SH. The use of mass losses determined by TGA to compare the binding of Con A to np-Au monoliths modified by mixed SAMs of αMan-C8-SH and either octanethiol or HO-PEG2-SH revealed that binding to mixed SAM modified surfaces is specific for the mixed SAMs with HO-PEG2-SH but shows a significant contribution from non-specific adsorption for the mixed SAMs with octanethiol. Minimal adsorption of immunoglobulin G (IgG) and peanut agglutinin (PNA) towards the mannoside modified np-Au monoliths was demonstrated. A greater mass loss was found for Con A bound onto the monolith than for either IgG or PNA, signifying that the mannose presenting SAMs in np-Au retain selectivity for Con A. TGA data also provide evidence that Con A bound to the αMan-C8-SH modified np-Au can be eluted by flowing a solution of methyl α-D-mannopyranoside through the structure. The presence of Con A proteins on the modified np-Au surface was

  16. Monolithic pixel detectors in silicon on insulator technology

    NASA Astrophysics Data System (ADS)

    Bisello, Dario

    2013-05-01

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  17. Pre-Launch Algorithm and Data Format for the Level 1 Calibration Products for the EOS AM-1 Moderate Resolution Imaging Spectroradiometer (MODIS)

    NASA Technical Reports Server (NTRS)

    Guenther, Bruce W.; Godden, Gerald D.; Xiong, Xiao-Xiong; Knight, Edward J.; Qiu, Shi-Yue; Montgomery, Harry; Hopkins, M. M.; Khayat, Mohammad G.; Hao, Zhi-Dong; Smith, David E. (Technical Monitor)

    2000-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) radiometric calibration product is described for the thermal emissive and the reflective solar bands. Specific sensor design characteristics are identified to assist in understanding how the calibration algorithm software product is designed. The reflected solar band software products of radiance and reflectance factor both are described. The product file format is summarized and the MODIS Characterization Support Team (MCST) Homepage location for the current file format is provided.

  18. Manufacturing of Monolithic Electrodes from Low-Cost Renewable Resources

    SciTech Connect

    McNutt, Nichiolas William; Rios, Orlando; Johs, Alexander; Tenhaeff, Wyatt E; Chatterjee, Sabornie; Keffer, David

    2014-01-01

    Lignin, a low-cost, biomass derived precursor, was selected as an alternative for carbon based free standing anodes in Li-ion batteries. Industrially scalable melt-spinning and melt-blowing synthesis methods were developed at Oak Ridge National Laboratory that are compatible with industrially viable production. Engineering studies predict that LCFs can be manufactured at $3/lb using these technologies, which compares favorably to $12/lb for battery grade graphite. The physical properties of lignin carbon fibers, specifically the tunable electrochemical and thermal transport, are suitable for energy storage applications as both an active material and current collector. The elimination of inactive components in the slurry-coated electrodes was enabled by LCF processing parameters modifications to produce monolithic mats in which the fibers are electrically interconnected. These mats were several hundreds of micrometers thick, and the fibers functioned as both current collector and active material by virtue of their mixed ionic/electronic conductivities. The LCFs were coated onto copper current collectors with PVDF binder and conductive carbon additive through conventional slurry processing. Galvanostatic cycling of the LCFs against Li revealed reversible capacities greater than 300 mAh/g. The coulombic efficiencies were over 99.8%. The mats were galvanostatically cycled in half cells against Li. Specific capacities as high as 250 mAh/g were achieved approximately 17% lower than the capacities of the same fibers in slurries. However, there were no inactive materials reducing the practical specific capacity of the entire electrode construction. Lithiation and delithiation of the LCFs proceeded with coulombic efficiencies greater than 99.9%, and the capacity retention was greater than 99% over 100 cycles at a rate of 15 mA/g. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for

  19. Disinfection byproduct formation during biofiltration cycle: Implications for drinking water production.

    PubMed

    Delatolla, R; Séguin, C; Springthorpe, S; Gorman, E; Campbell, A; Douglas, I

    2015-10-01

    The goal of this study was to investigate the potential of biofiltration to reduce the formation potential of disinfection byproducts (DBPs). Particularly, the work investigates the effect of the duration of the filter cycle on the formation potential of total trihalomethanes (TTHM) and five species of haloacetic acids (HAA5), dissolved oxygen (DO), organic carbon, nitrogen and total phosphorous concentrations along with biofilm coverage of the filter media and biomass viability of the attached cells. The study was conducted on a full-scale biologically active filter, with anthracite and sand media, at the Britannia water treatment plant (WTP), located in Ottawa, Ontario, Canada. The formation potential of both TTHMs and HAA5s decreased due to biofiltration. However the lowest formation potentials for both groups of DBPs and or their precursors were observed immediately following a backwash event. Hence, the highest percent removal of DBPs was observed during the early stages of the biofiltration cycle, which suggests that a higher frequency of backwashing will reduce the formation of DBPs. Variable pressure scanning electron microscopy (VPSEM) analysis shows that biofilm coverage of anthracite and sand media increases as the filtration cycle progressed, while biomass viability analysis demonstrates that the percentage of cells attached to the anthracite and sand media also increases as the filtration cycle progresses. These results suggest that the development and growth of biofilm on the filters increases the DPB formation potential.

  20. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Allen, Phillip Grant

    2011-01-01

    High-power ultrasonic actuators are generally assembled with a horn, backing, stress bolt, piezoelectric rings, and electrodes. The manufacturing process is complex, expensive, difficult, and time-consuming. The internal stress bolt needs to be insulated and presents a potential internal discharge point, which can decrease actuator life. Also, the introduction of a center hole for the bolt causes many failures, reducing the throughput of the manufactured actuators. A new design has been developed for producing ultrasonic horn actuators. This design consists of using flexures rather than stress bolts, allowing one to apply pre-load to the piezoelectric material. It also allows one to manufacture them from a single material/plate, rapid prototype them, or make an array in a plate or 3D structure. The actuator is easily assembled, and application of pre-stress greater than 25 MPa was demonstrated. The horn consists of external flexures that eliminate the need for the conventional stress bolt internal to the piezoelectric, and reduces the related complexity. The stress bolts are required in existing horns to provide prestress on piezoelectric stacks when driven at high power levels. In addition, the manufacturing process benefits from the amenability to produce horn structures with internal cavities. The removal of the pre-stress bolt removes a potential internal electric discharge point in the actuator. In addition, it significantly reduces the chances of mechanical failure in the piezoelectric stacks that result from the hole surface in conventional piezoelectric actuators. The novel features of this disclosure are: 1. A design that can be manufactured from a single piece of metal using EDM, precision machining, or rapid prototyping. 2. Increased electromechanical coupling of the horn actuator. 3. Higher energy density. 4. A monolithic structure of a horn that consists of an external flexure or flexures that can be used to pre-stress a solid piezoelectric structure