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Sample records for carbon bonds clean

  1. Cogeneration and Carbon bonds: clean development; Cogeneracion y bonos de carbono: desarrollo limpio

    Energy Technology Data Exchange (ETDEWEB)

    Navarro Perez, Nidia [Facultad de Contaduria y Administracion, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2004-06-15

    The growing preoccupation for the environment in our country and its interest to ratify the Kyoto Protocol with respect to the contamination of the atmosphere, offers great opportunities for the cogeneration so that it fortifies the scientific and technological research and gives a good international image about the sustainable development and care of the environment, so that companies that invest in clean technology will be able to assign a monetary value to their environmental patrimony, this through the so called Green Bonds or Carbon Bonds, this opens a new dimension to finance projects by means of these bonds that can be negotiated at an international level; by means of the Clean of Energy Production the investment can be stimulated and revenues for projects that contribute to the sustainable development of the country and the power efficiency. At the moment the country has at least 13 projects in different analysis stages to enter the carbon bond market, which are presented as co-generation projects of energy, in addition to the formation of the Mexican Committee for Projects of Reduction and Capture of Gas Discharges of Greenhouse Effect. [Spanish] La creciente preocupacion por el medio ambiente en nuestro pais y su interes por ratificar el Protocolo de Kyoto en lo referente a la contaminacion de la atmosfera, ofrece grandes oportunidades para la cogeneracion de manera que fortalezca la investigacion cientifica y tecnologica y dar una buena imagen internacional en torno a temas de desarrollo sustentable y cuidado del medio ambiente, de manera que empresas que invierten en tecnologia limpia podran asignar un valor monetario a su patrimonio ambiental, esto a traves de los llamados Bonos Verdes o Bonos de Carbono, esto abre una dimension nueva para financiar proyectos por medio de estos bonos que pueden negociarse a nivel internacional; por medio de la Produccion Limpia de energia se puede estimular inversion y ganancias para proyectos que contribuyan al

  2. Carbon dioxide cleaning pilot project

    International Nuclear Information System (INIS)

    In 1989, radioactive-contaminated metal at the Rocky Flats Plant (RFP) was cleaned using a solvent paint stripper (Methylene chloride). One-third of the radioactive material was able to be recycled; two-thirds went to the scrap pile as low-level mixed waste. In addition, waste solvent solutions also required disposal. Not only was this an inefficient process, it was later prohibited by the Resource Conservation and Recovery Act (RCRA), 40 CFR 268. A better way of doing business was needed. In the search for a solution to this situation, it was decided to study the advantages of using a new technology - pelletized carbon dioxide cleaning. A proof of principle demonstration occurred in December 1990 to test whether such a system could clean radioactive-contaminated metal. The proof of principle demonstration was expanded in June 1992 with a pilot project. The purpose of the pilot project was three fold: (1) to clean metal so that it can satisfy free release criteria for residual radioactive contamination at the Rocky Flats Plant (RFP); (2) to compare two different carbon dioxide cleaning systems; and (3) to determine the cost-effectiveness of decontamination process in a production situation and compare the cost of shipping the metal off site for waste disposal. The pilot project was completed in August 1993. The results of the pilot project were: (1) 90% of those items which were decontaminated, successfully met the free release criteria , (2) the Alpheus Model 250 was selected to be used on plantsite and (3) the break even cost of decontaminating the metal vs shipping the contaminated material offsite for disposal was a cleaning rate of 90 pounds per hour, which was easily achieved

  3. Evaluation of cleaning procedures and bonding materials for TPX plastic

    International Nuclear Information System (INIS)

    TPX plastic parts currently undergo a chromium trioxide acid etch and polyolefin primer application prior to being bonded to LX-17 explosive parts with Exlostik 473. This study evaluates Explostik 473 (epoxy), APC 2.5 (Silicone) and Hexcel Uralite 3121 S (urethane) adhesives and several surface treatments. These surface treatments include acid etch; acid etch and polyolefin primer; polyolefin primer; oxygen plasma clean; oxygen plasma clean and polyolefin primer. Results indicate that oxygen plasma cleaning is the best surface treatment. Plasma treatment times as short as 2.5 min do an adequate job. Plasma-treated parts remain clean and bondable for at least 16 days after treatment

  4. Carbon nanotubes – becoming clean

    Directory of Open Access Journals (Sweden)

    Nicole Grobert

    2007-01-01

    Full Text Available Carbon nanotubes (CNTs are now well into their teenage years. Early on, theoretical predictions and experimental data showed that CNTs possess chemical and mechanical properties that exceed those of many other materials. This has triggered intense research into CNTs. A variety of production methods for CNTs have been developed; chemical modification, functionalization, filling, and doping have been achieved; and manipulation, separation, and characterization of individual CNTs is now possible. Today, products containing CNTs range from tennis rackets and golf clubs to vehicle fenders, X-ray tubes, and Li ion batteries. Breakthroughs for CNT-based technologies are anticipated in the areas of nanoelectronics, biotechnology, and materials science. In this article, I review the current situation in CNT production and highlight the importance of clean CNT material for the success of future applications.

  5. Chemical cleaning agents and bonding to glass-fiber posts

    Directory of Open Access Journals (Sweden)

    Ana Paula Rodrigues Gonçalves

    2013-02-01

    Full Text Available The influence of chemical cleaning agents on the bond strength between resin cement and glass-fiber posts was investigated. The treatments included 10% hydrofluoric acid, 35% phosphoric acid, 50% hydrogen peroxide, acetone, dichloromethane, ethanol, isopropanol, and tetrahydrofuran. Flat glass-fiber epoxy substrates were exposed to the cleaners for 60 s. Resin cement cylinders were formed on the surfaces and tested in shear. All treatments provided increased bond strength compared to untreated control specimens. All failures were interfacial. Although all agents improved the bond strength, dichloromethane and isopropanol were particularly effective.

  6. Reactive Bonding Film for Bonding Carbon Foam Through Metal Extrusion

    CERN Document Server

    Chertok, Maxwell; Irving, Michael; Neher, Christian; Tripathi, Mani; Wang, Ruby; Zheng, Gayle

    2016-01-01

    Future tracking detectors, such as those under development for the High Luminosity LHC, will require mechanical structures employing novel materials to reduce mass while providing excellent strength, thermal conductivity, and radiation tolerance. Adhesion methods for such materials are under study at present. This paper demonstrates the use of reactive bonding film as an adhesion method for bonding carbon foam.

  7. Carbon Nanotube Bonding Strength Enhancement Using Metal "Wicking" Process

    Science.gov (United States)

    Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

    2012-01-01

    Carbon nanotubes grown from a surface typically have poor bonding strength at the interface. A process has been developed for adding a metal coat to the surface of carbon nano tubes (CNTs) through a wicking process, which could lead to an enhanced bonding strength at the interface. This process involves merging CNTs with indium as a bump-bonding enhancement. Classical capillary theory would not normally allow materials that do not wet carbon or graphite to be drawn into the spacings by capillary action because the contact angle is greater than 90 degrees. However, capillary action can be induced through JPL's ability to fabricate oriented CNT bundles to desired spacings, and through the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. A reflow and plasma cleaning process has also been developed and demonstrated to remove indium oxide, and to obtain smooth coatings on the CNT bundles.

  8. Covalent bond orders for non-bonded atoms: The case for carbon-carbon interactions

    International Nuclear Information System (INIS)

    The Cioslowski-Mixon (CM) covalent bond order and the atoms-in-molecules (AIM) delocalization index can be used to study bonding characteristics between atoms not bonded in the conventional chemical sense. In particular, the bond orders between atoms (AIM basins) with one intervening atom evolve in a predictable manner and are related to the bond orders of conventionally bonded species. The CM approach shows that it is the tails of the incompletely localized orbitals that provide for such interactions. Single, multiple, and resonant bond effects are seen which are physically meaningful and useful as an additional characterization of molecular bonding. The important case of carbon-carbon interactions is studied here.

  9. Cleaning of ITO glass with carbon dioxide snow jet spray

    Science.gov (United States)

    Li, Jun-jian; Qi, Tong; Li, Shu-lin; Zhao, Guang

    2007-12-01

    ITO glass cleaning is LCD, OLED and other flat panel display industry's key technologies. At present, the usual wet cleaning technology consumes large amount of water and chemicals, and produces a large amount of contaminant venting. CO II snow jet spray cleaning has been successfully applied to cleaning the surface of semiconductor chip, vacuum devices and space telescopes. Surface cleaning of indium tin oxide (ITO) film was carried out with carbon dioxide snow jet treatment .Based on the measurements of the contact angles, X-ray photoelectron spectroscopy and scanning electron microscopy (SEM) ,the influence of carbon dioxide snow jet treatment on surface cleaning of indium tin Oxide film was investigated and compared with the samples of low frequency immersion ultrasonic cleaning. Experimental data show that the carbon dioxide snow jet treatment effectively removes particulate and hydrocarbon on ITO surface.

  10. The clean development mechanism in a globalized carbon market

    OpenAIRE

    Thierry Bréchet; Yann Ménière; Picard, Pierre M

    2011-01-01

    This paper discusses the role of the Clean DevelopmentMechanisms (CDM) on the market for carbon quotas and countries' commitments to reduce their carbon emission levels. We show that the CDM contributes to an efficient funding of clean technology investments in least developed countries. How- ever, the CDM is not neutral on the global level of carbon emissions as it entices countries to raise their emission caps. The CDM may also make inap- propriate the inclusion of any country that makes no...

  11. Clean Energy Manufacturing Analysis Center. 2015 Research Highlights -- Carbon Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-01

    CEMAC has conducted four major studies on the manufacturing of clean energy technologies. Three of these focused on the end product: solar photovoltaic modules, wind turbines, and automotive lithium-ion batteries. The fourth area focused on a key material for manufacturing clean energy technologies, carbon fiber.

  12. Effect of cleaning methods on bond strength of self-etching adhesive to dentin

    Directory of Open Access Journals (Sweden)

    Juliana Delatorre Bronzato

    2016-01-01

    Full Text Available Aim: The aim of this study was to investigate the influence of cleaning methods to remove zinc oxide-eugenol-based root canal sealer (Endomethasone on the bond strength of the self-etching adhesive to dentin. Materials and Methods: Twenty crowns of bovine incisors were cut to expose the pulp chamber. A zinc oxide- and eugenol-based sealer was placed for 10 min in contact with the pulp chamber dentin. Specimens were divided into four groups according to the cleaning method of dentin used: G1, no root canal sealer (control; G2, 0.9% sodium chlorite (NaCl; G3, ethanol; and G4, followed by diamond drill. After cleaning, the teeth were restored with composite resin and Clearfil SE Bond. All specimens were sectioned to produce rectangular sticks and dentin/resin interface was submitted to microtensile bond testing. The mean bond strengths were analyzed using ANOVA/Tukey (α = 0.05. Results: G3 and G4 showed bond strengths similar to the G1 (P > 0.05. A significant decrease in the bond strength in the G2 was observed (P < 0.05. G1, G3, and G4, the predominant failure mode was the mixed type. The prevalence of adhesive failure mode was verified in the G2. Conclusion: The cleaning methods affected the bond strength of the self-etching adhesive to dentin differently.

  13. Various Carbon to Carbon Bond Lengths Inter-related via the Golden Ratio, and their Linear Dependence on Bond Energies

    CERN Document Server

    Heyrovska, Raji

    2008-01-01

    This work presents the relations between the carbon to carbon bond lengths in the single, double and triple bonds and in graphite, butadiene and benzene. The Golden ratio, which was shown to divide the Bohr radius into two parts pertaining to the charged particles, the electron and proton, and to divide inter-atomic distances into their cationic and anionic radii, also plays a role in the carbon-carbon bonds and in the ionic/polar character of those in graphite, butadiene and benzene. Further, the bond energies of the various CC bonds are shown to vary linearly with the bond lengths.

  14. Bonding between Carbon Fiver/Carbon composite and copper alloy

    International Nuclear Information System (INIS)

    In order to develop material for Divertor of Nuclear Fusion Reactor, we investigated bonding method between C-C material (Carbon Fiber/Carbon composite) and three kinds of heat sink materials, the microstructure of the bonding layer, shearing strength, thermal shock resistance temperature and analysis of thermal stress. C-C material was manufactured with carbon fiber oriented in one direction. Thermal conductivity of C-C is 570 W/m·k along this orientation. For heat sink material, three kinds of material, Cu, Cr-Cu alloy and W-Cu alloy were used. Results are summarized below; (1) As a brazing filler metal for bonding between C-C and copper alloy, ten kinds of brazing filler metals were investigated. As a result 2Ti-AgCu paste filler metal was selected. The brazing filler metal is excellent in wettability and as high shearing strength as a bonding layer. (2) Shearing strengths of the C-C/copper and copper alloy joints with 2Ti-AgCu paste brazing filler metal decrease in the order of C-C/Cu, C-C/Cr-Cu, C-C/W-Cu. Hardness of the bonding layer decrease in the order of C-C/W-Cu, C-C/Cr-Cu and C-C/Cu. Therefore, the shearing strength of the bonding layer increase with decreasing hardness. (3) By using a copper plate of 2-5 mm in thickness as a bonding layer between of C-C/Cr-Cu and C-C/W-Cu joints, shearing strength and thermal shock resistance temperature are improved to those of the C-C/Cu joint. Through thermal stress analysis, the thermal stress relief of the copper plate was confirmed. (author)

  15. Carbonate clumped isotope bond reordering and geospeedometry

    Science.gov (United States)

    Passey, Benjamin H.; Henkes, Gregory A.

    2012-10-01

    Carbonate clumped isotope thermometry is based on the preference of 13C and 18O to form bonds with each other. At elevated temperatures such bond ordering is susceptible to resetting by diffusion of C and O through the solid mineral lattice. This type of bond reordering has the potential to obscure primary paleoclimate information, but could also provide a basis for reconstructing shallow crustal temperatures and cooling rates. We determined Arrhenius parameters for solid-state reordering of C-O bonds in two different calcites through a series of laboratory heating experiments. We find that the calcites have different susceptibilities to solid-state reordering. Reaction progress follows a first order rate law in both calcites, but only after an initial period of non-first order reaction that we suggest relates to annealing of nonequilibrium defects when the calcites are first heated to experimental temperature. We show that the apparent equilibrium temperature equations (or "closure temperature" equations) for carbonate clumped isotope reordering are analogous Dodson's equations for first order loss of daughter isotopes. For each calcite, the sensitivity of apparent equilibrium temperature to cooling rate is sufficiently high for inference of cooling rates within a factor of ˜5 or better for cooling rates ranging from tens of degrees per day to a few degrees per million years. However, because the calcites have different susceptibilities to reordering, each calcite defines its own cooling rate-apparent equilibrium temperature relationship. The cooling rates of Carrara marble inferred from carbonate clumped isotope geospeedometry are 10-6-10-3 degrees per annum and are in broad agreement with rates inferred from thermochronometric methods. Cooling rates for 13C-depleted calcites from the late Neoproterozoic Doushantou cap carbonates in south China are on the order of 102-104 degrees per annum, consistent with rapid cooling following formation of these calcites by a

  16. Aviation, Carbon, and the Clean Air Act

    OpenAIRE

    Richardson, Nathan

    2012-01-01

    This paper explores the policy options available to the United States for regulating greenhouse gas emissions from aircraft under existing law: the Clean Air Act (CAA). Europe has unilaterally and controversially moved to include aviation emissions in its Emissions Trading System. The United States can, however, allow its airlines to escape this requirement by imposing “equivalent” regulation. U.S. aviation emissions rules could also have significant environmental benefits and would limit dom...

  17. Investigation of the impact of cleaning on the adhesive bond and the process implications

    Energy Technology Data Exchange (ETDEWEB)

    EMERSON,JOHN A.; GUESS,TOMMY R.; ADKINS,CAROL L. JONES; CURRO,JOHN G.; REEDY JR.,EARL DAVID; LOPEZ,EDWIN P.; LEMKE,PAUL A.

    2000-05-01

    While surface cleaning is the most common process step in DOE manufacturing operations, the link between a successful adhesive bond and the surface clean performed before adhesion is not well understood. An innovative approach that combines computer modeling expertise, fracture mechanics understanding, and cleaning experience to address how to achieve a good adhesive bond is discussed here to develop a capability that would result in reduced cleaning development time and testing, improved bonds, improved manufacturability, and even an understanding that leads to improved aging. A simulation modeling technique, polymer reference interaction site model applied near wall (Wall PRISM), provided the capability to include contaminants on the surface. Calculations determined an approximately 8% reduction in the work of adhesion for 1% by weight of ethanol contamination on the structure of a silicone adhesive near a surface. The demonstration of repeatable coatings and quantitative analysis of the surface for deposition of controlled amounts of contamination (hexadecane and mineral oil) was based on three deposition methods. The effect of the cleaning process used on interfacial toughness was determined. The measured interfacial toughness of samples with a Brulin cleaned sandblasted aluminum surface was found to be {approximately} 15% greater than that with a TCE cleaned aluminum surface. The sensitivity of measured fracture toughness to various test conditions determined that both interfacial toughness and interface corner toughness depended strongly on surface roughness. The work of adhesion value for silicone/silicone interface was determined by a contact mechanics technique known as the JKR method. Correlation with fracture data has allowed a better understanding between interfacial fracture parameters and surface energy.

  18. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Among the...

  19. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Included among...

  20. Fabric compatibility and cleaning effectiveness of drycleaning with carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Williams, S.B.; Laintz, K.E.; Spall, W.D.; bustos, L.; Taylor, C.

    1996-04-01

    Liquid carbon dioxide (CO{sub 2}) offers an environmentally sound replacement solvent to the currently used drycleaning solvent, perchloroethylene (PERC). In addition to the health and safety benefits of a CO{sub 2} based cleaning system, large savings in solvent costs provide an incentive for conversion to the new system. Lower operating costs for the new technology provide further incentive. Experimental studies were conducted using CO{sub 2} in both small scale and pilot scale test systems in order to address fabric compatibility with this alternative cleaning method. Results from these tests show that fabric shrinkage using CO{sub 2} is controlled to the same level as current drycleaning methods. In addition, tests to evaluate the cleaning performance of liquid CO{sub 2} drycleaning were also conducted. These results show the prototype liquid CO{sub 2} cleaning system to be better than PERC at soil removal, and worse than PERC at inorganic salt removal.

  1. Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.

    OpenAIRE

    Tsuji, Yasushi; Fujihara, Tetsuaki

    2012-01-01

    Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role.

  2. Preservation of atomically clean silicon surfaces in air by contact bonding

    DEFF Research Database (Denmark)

    Grey, Francois; Ljungberg, Karin

    1997-01-01

    ordered atomic structure of the surfaces is protected from oxidation, even after the bonded samples have been in air for weeks. Further, we show that silicon surfaces that have been cleaned and hydrogen-passivated in UHV can be contacted in UHV in a similarly hermetic fashion, protecting the surface...... reconstruction from oxidation in air, Contact bonding opens the way to novel applications of reconstructed semiconductor surfaces, by preserving their atomic structure intact outside of a UHV chamber. (C) 1997 American Institute of Physics....

  3. Various Carbon to Carbon Bond Lengths Inter-related via the Golden Ratio, and their Linear Dependence on Bond Energies

    OpenAIRE

    Heyrovska, Raji

    2008-01-01

    This work presents the relations between the carbon to carbon bond lengths in the single, double and triple bonds and in graphite, butadiene and benzene. The Golden ratio, which was shown to divide the Bohr radius into two parts pertaining to the charged particles, the electron and proton, and to divide inter-atomic distances into their cationic and anionic radii, also plays a role in the carbon-carbon bonds and in the ionic/polar character of those in graphite, butadiene and benzene. Further...

  4. Method for in-situ cleaning of carbon contaminated surfaces

    Science.gov (United States)

    Klebanoff, Leonard E.; Grunow, Philip; Graham, Jr., Samuel

    2006-12-12

    Activated gaseous species generated adjacent a carbon contaminated surface affords in-situ cleaning. A device for removing carbon contamination from a surface of the substrate includes (a) a housing defining a vacuum chamber in which the substrate is located; (b) a source of gaseous species; and (c) a source of electrons that are emitted to activate the gaseous species into activated gaseous species. The source of electrons preferably includes (i) a filament made of a material that generates thermionic electron emissions; (ii) a source of energy that is connected to the filament; and (iii) an electrode to which the emitted electrons are attracted. The device is particularly suited for photolithography systems with optic surfaces, e.g., mirrors, that are otherwise inaccessible unless the system is dismantled. A method of removing carbon contaminants from a substrate surface that is housed within a vacuum chamber is also disclosed. The method employs activated gaseous species that react with the carbon contaminants to form carbon containing gaseous byproducts.

  5. Making End-Bonded Contacts to Carbon Nanotubes

    Science.gov (United States)

    Tang, Jianshi; Cao, Qing; Tulevski, George; Han, Shu-Jen

    As a promising candidate for post-Si era, the implementation of carbon nanotube (CNT)-based CMOS technology requires both high-quality channel and electrical contacts that can be scaled down to sub-10 nm. In the efforts of making scalable contacts to CNT, we have recently demonstrated low-resistance end-bonded carbide contacts, formed by the reaction of Mo with CNT through high-temperature annealing (>800 oC). Such end-bonded contact scheme leads to a size-independent contact resistance of about 30 kilo-ohms, which overcomes the scaling limit of conventional side contacts. In this talk, we will present another strategy to make end-bonded contacts to CNTs through thermal annealing at much lower temperatures (400-600 oC). The contact metals are carefully chosen to have a high carbon solubility, so that the carbon atoms could dissolve into the contacts to inherently form end-bonded contacts. Experimental results, including Raman, SEM, and electrical measurements, with different annealing temperatures will be presented. The length-dependent contact resistance for this new end-bonded contact will be evaluated and compared with that of conventional side contact and also end-bonded carbide contact.

  6. Application of Sol Self-Clean Bonded Al2O3-SiC-C Castable for Iron Runner

    Institute of Scientific and Technical Information of China (English)

    XU Guotao; ZHANG Honglei; CHEN Huasheng; WANG Yue; LI Huaiyuan; XIONG Yafei

    2006-01-01

    The properties and microstructure of sol self-clean bonded Al2O3-SiC-C castable in iron runner were studied, and the relation between the amount of sol selfclean binder and the properties of castable were discussed. It is believed that the addition of sol self-clean binder can improve the compressive strength, but has little effect on the bulk density and the apparent porosity,which enable the castable to be applicable in different conditions.

  7. Development of Statistical Process Control Methodology for an Environmentally Compliant Surface Cleaning Process in a Bonding Laboratory

    Science.gov (United States)

    Hutchens, Dale E.; Doan, Patrick A.; Boothe, Richard E.

    1997-01-01

    Bonding labs at both MSFC and the northern Utah production plant prepare bond test specimens which simulate or witness the production of NASA's Reusable Solid Rocket Motor (RSRM). The current process for preparing the bonding surfaces employs 1,1,1-trichloroethane vapor degreasing, which simulates the current RSRM process. Government regulations (e.g., the 1990 Amendments to the Clean Air Act) have mandated a production phase-out of a number of ozone depleting compounds (ODC) including 1,1,1-trichloroethane. In order to comply with these regulations, the RSRM Program is qualifying a spray-in-air (SIA) precision cleaning process using Brulin 1990, an aqueous blend of surfactants. Accordingly, surface preparation prior to bonding process simulation test specimens must reflect the new production cleaning process. The Bonding Lab Statistical Process Control (SPC) program monitors the progress of the lab and its capabilities, as well as certifies the bonding technicians, by periodically preparing D6AC steel tensile adhesion panels with EA-91 3NA epoxy adhesive using a standardized process. SPC methods are then used to ensure the process is statistically in control, thus producing reliable data for bonding studies, and identify any problems which might develop. Since the specimen cleaning process is being changed, new SPC limits must be established. This report summarizes side-by-side testing of D6AC steel tensile adhesion witness panels and tapered double cantilevered beams (TDCBs) using both the current baseline vapor degreasing process and a lab-scale spray-in-air process. A Proceco 26 inches Typhoon dishwasher cleaned both tensile adhesion witness panels and TDCBs in a process which simulates the new production process. The tests were performed six times during 1995, subsequent statistical analysis of the data established new upper control limits (UCL) and lower control limits (LCL). The data also demonstrated that the new process was equivalent to the vapor

  8. Decrudding and chemical cleaning of carbon steel components - an evaluation

    International Nuclear Information System (INIS)

    Corrosion and accumulation of corrosion products on the surfaces of structural components and plant equipments can cause se vereoperational problems during service. An illustration is the heat exchanger systems in nuclear power stations. Development and standardisation of appropriate chemical cleaning and decontamination procedures and their evaluation hence merit serious consideration. A number of chemical cleaning procedures using formulations based on hydrochloric and citric acid solutions have been examined to study their crud dissolving and derusting ability in addition to the attack on base material. The compositions were chosen: (1) along with complexing agents EDTA and ammonium citrate, (2) with pH control, and (3) with the use of inhibitors acridine, rhodine, hexamine and phenyl-thiourea. The evaluations have been made at 28 and 60 deg C. Rusted carbon steel coupons having a rust of 10-12 mg/cm2 on the surface have been used for the purpose of the above evaluations. Data on corrosion rates of monel and cupronickel (70:30) in the descaling solutions have also been presented. Results on the above evaluation studies have been discussed. (author)

  9. Stable alkanes containing very long carbon-carbon bonds.

    Science.gov (United States)

    Fokin, Andrey A; Chernish, Lesya V; Gunchenko, Pavel A; Tikhonchuk, Evgeniya Yu; Hausmann, Heike; Serafin, Michael; Dahl, Jeremy E P; Carlson, Robert M K; Schreiner, Peter R

    2012-08-22

    The metal-induced coupling of tertiary diamondoid bromides gave highly sterically congested hydrocarbon (hetero)dimers with exceptionally long central C-C bonds of up to 1.71 Å in 2-(1-diamantyl)[121]tetramantane. Yet, these dimers are thermally very stable even at temperatures above 200 °C, which is not in line with common C-C bond length versus bond strengths correlations. We suggest that the extraordinary stabilization arises from numerous intramolecular van der Waals attractions between the neighboring H-terminated diamond-like surfaces. The C-C bond rotational dynamics of 1-(1-adamantyl)diamantane, 1-(1-diamantyl)diamantane, 2-(1-adamantyl)triamantane, 2-(1-diamantyl)triamantane, and 2-(1-diamantyl)[121]tetramantane were studied through variable-temperature (1)H- and (13)C NMR spectroscopies. The shapes of the inward (endo) CH surfaces determine the dynamic behavior, changing the central C-C bond rotation barriers from 7 to 33 kcal mol(-1). We probe the ability of popular density functional theory (DFT) approaches (including BLYP, B3LYP, B98, B3LYP-Dn, B97D, B3PW91, BHandHLYP, B3P86, PBE1PBE, wB97XD, and M06-2X) with 6-31G(d,p) and cc-pVDZ basis sets to describe such an unusual bonding situation. Only functionals accounting for dispersion are able to reproduce the experimental geometries, while most DFT functionals are able to reproduce the experimental rotational barriers due to error cancellations. Computations on larger diamondoids reveal that the interplay between the shapes and the sizes of the CH surfaces may even allow the preparation of open-shell alkyl radical dimers (and possibly polymers) that are strongly held together exclusively by dispersion forces. PMID:22835264

  10. Oxygen reduction on teflon-bonded carbon electrode

    Institute of Scientific and Technical Information of China (English)

    周德璧; 黄可龙; 张世民

    2004-01-01

    Oxygen reduction on Teflon-bonded carbon gas diffusion electrode without catalyst in 6 mol/L KOH solution was investigated with acimpedance spectroscopy and other electrochemical techniques. The kinetic parameters were measured with an exchange current density of J0= 3.44 × 10-9 and a Tafel slope of 46 mV/dec in low overpotential range (-0.05 --0.14 V vs SCE), which are comparable with those reported on carbon supported platinum electrode. The reaction mechanism of OR and the active effect of carbon black were examined.

  11. Structural and bonding trends in platinum-carbon clusters

    OpenAIRE

    Miller, Thomas F., III; Hall, Michael B.

    1999-01-01

    Density functional calculations with the B3-LYP functional were used to optimize the platinum−carbon cationic clusters, PtC_x^+, 1 ≤ x ≤ 16, in both the doublet and quartet states of the linear, fan, open-ring, closed-ring, and one-carbon-ring geometries. Trends in stability, Pt^+−C_x binding energy, doublet-quartet excitation energy, and Pt−C bond lengths were investigated. Explanations for these patterns are provided in terms of orbital interactions and changes imposed on the carbon chain b...

  12. Cleaning Carbon Nanotubes by Use of Mild Oxygen Plasmas

    Science.gov (United States)

    Petkov, Mihail

    2006-01-01

    Experiments have shown that it is feasible to use oxygen radicals (specifically, monatomic oxygen) from mild oxygen plasmas to remove organic contaminants and chemical fabrication residues from the surfaces of carbon nanotubes (CNTs) and metal/CNT interfaces. A capability for such cleaning is essential to the manufacture of reproducible CNT-based electronic devices. The use of oxygen radicals to clean surfaces of other materials is fairly well established. However, previously, cleaning of CNTs and of graphite by use of oxygen plasmas had not been attempted because both of these forms of carbon were known to be vulnerable to destruction by oxygen plasmas. The key to success of the present technique is, apparently, to ensure that the plasma is mild . that is to say, that the kinetic and internal energies of the oxygen radicals in the plasma are as low as possible. The plasma oxygen-radical source used in the experiments was a commercial one marketed for use in removing hydrocarbons and other organic contaminants from vacuum systems and from electron microscopes and other objects placed inside vacuum systems. In use, the source is installed in a vacuum system and air is leaked into the system at such a rate as to maintain a background pressure of .0.56 torr (.75 Pa). In the source, oxygen from the air is decomposed into monatomic oxygen by radio-frequency excitation of a resonance of the O2 molecule (N2 is not affected). Hence, what is produced is a mild (non-energetic) oxygen plasma. The oxygen radicals are transported along with the air molecules in the flow created by the vacuum pump. In the experiments, exposure to the oxygen plasma in this system was shown to remove organic contaminants and chemical fabrication residues from several specimens. Many high-magnification scanning electron microscope (SEM) images of CNTs were taken before and after exposure to the oxygen plasma. As in the example shown in the figure, none of these images showed evidence of degradation

  13. Effect of Carbon Containing Materials on Pure Carbon Reaction-bonded SiC

    Institute of Scientific and Technical Information of China (English)

    JI Xiaoli; WEI Lei; SUN Feng

    2008-01-01

    Petroleum coke, graphite, gas carbon and lower sulfur carbon black were used to prepare reaction-bonded silicon carbide. The influences of different carbon containing materials on properties of carbonaceous precursors, sintering process, and microstructure of the prepared SiC were researched. The results show that:(1)With the density of carbon containing materials increasing, the porosity of carbonaceous precursors decreases and the infiltrating process of liquid silicon is more difficult.(2)The reaction between carbon containing materials and liquid silicon, the volume effect is more obvious with the density of carbon containing materials increasing.(3)As the carbon containing materials density decreasing, residual carbon in reaction bonded SiC also decreases.

  14. An analytical bond-order potential for carbon.

    Science.gov (United States)

    Zhou, X W; Ward, D K; Foster, M E

    2015-09-01

    Carbon is the most widely studied material today because it exhibits special properties not seen in any other materials when in nano dimensions such as nanotube and graphene. Reduction of material defects created during synthesis has become critical to realize the full potential of carbon structures. Molecular dynamics (MD) simulations, in principle, allow defect formation mechanisms to be studied with high fidelity, and can, therefore, help guide experiments for defect reduction. Such MD simulations must satisfy a set of stringent requirements. First, they must employ an interatomic potential formalism that is transferable to a variety of carbon structures. Second, the potential needs to be appropriately parameterized to capture the property trends of important carbon structures, in particular, diamond, graphite, graphene, and nanotubes. Most importantly, the potential must predict the crystalline growth of the correct phases during direct MD simulations of synthesis to achieve a predictive simulation of defect formation. Because an unlimited number of structures not included in the potential parameterization are encountered, the literature carbon potentials are often not sufficient for growth simulations. We have developed an analytical bond order potential for carbon, and have made it available through the public MD simulation package LAMMPS. We demonstrate that our potential reasonably captures the property trends of important carbon phases. Stringent MD simulations convincingly show that our potential accounts not only for the crystalline growth of graphene, graphite, and carbon nanotubes but also for the transformation of graphite to diamond at high pressure. PMID:26018402

  15. Study on effective laser cleaning method to remove carbon layer from a gold surface

    International Nuclear Information System (INIS)

    Hydrocarbon cracking and carbon contamination is a common problem in soft x-ray Synchrotron Radiation (SR) beamlines. Carbon contamination on optics is known to absorb and scatter radiation close to the C K-edge (284 eV) spectral region. The purpose of this work is to study and develop a laser cleaning method that can effectively remove the carbon contaminations without damaging the underneath gold-coated optics. The laser cleaning process is a non-contact, accurate, efficient and safe. Nd:YAG laser of 100 ns pulse duration is used for carbon cleaning. The effect of laser pulse duration, laser fluence, number of laser passes, angle of incidence and spot overlapping on the cleaning performance is studied. Cleaning effect and subsequent film quality after laser irradiation is analyzed using x-ray photoelectron spectroscopy (XPS) and soft x-ray reflectivity (SXR) techniques.

  16. Peptide Bond Formation in Water Mediated by Carbon Disulfide.

    Science.gov (United States)

    Leman, Luke J; Huang, Zheng-Zheng; Ghadiri, M Reza

    2015-09-01

    Demonstrating plausible nonenzymatic polymerization mechanisms for prebiotic monomers represents a fundamental goal in prebiotic chemistry. While a great deal is now known about the potentially prebiotic synthesis of amino acids, our understanding of abiogenic polymerization processes to form polypeptides is less well developed. Here, we show that carbon disulfide (CS2), a component of volcanic emission and sulfide mineral weathering, and a widely used synthetic reagent and solvent, promotes peptide bond formation in modest yields (up to ∼20%) from α-amino acids under mild aqueous conditions. Exposure of a variety of α-amino acids to CS2 initially yields aminoacyl dithiocarbamates, which in turn generate reactive 2-thiono-5-oxazolidone intermediates, the thio analogues of N-carboxyanhydrides. Along with peptides, thiourea and thiohydantoin species are produced. Amino acid stereochemistry was preserved in the formation of peptides. Our findings reveal that CS2 could contribute to peptide bond formation, and possibly other condensation reactions, in abiogenic settings. PMID:26308392

  17. Carbon-carbon composite and copper-composite bond damages for high flux component controlled fusion

    International Nuclear Information System (INIS)

    Plasma facing components constitute the first wall in contact with plasma in fusion machines such as Tore Supra and ITER. These components have to sustain high heat flux and consequently elevated temperatures. They are made up of an armour material, the carbon-carbon composite, a heat sink structure material, the copper chromium zirconium, and a material, the OFHC copper, which is used as a compliant layer between the carbon-carbon composite and the copper chromium zirconium. Using different materials leads to the apparition of strong residual stresses during manufacturing, because of the thermal expansion mismatch between the materials, and compromises the lasting operation of fusion machines as damage which appeared during manufacturing may propagate. The objective of this study is to understand the damage mechanisms of the carbon-carbon composite and the composite-copper bond under solicitations that plasma facing components may suffer during their life. The mechanical behaviours of carbon-carbon composite and composite-copper bond were studied in order to define the most suitable models to describe these behaviours. With these models, thermomechanical calculations were performed on plasma facing components with the finite element code Cast3M. The manufacturing of the components induces high stresses which damage the carbon-carbon composite and the composite-copper bond. The damage propagates during the cooling down to room temperature and not under heat flux. Alternative geometries for the plasma facing components were studied to reduce damage. The relation between the damage of the carbon-carbon composite and its thermal conductivity was also demonstrated. (author)

  18. Institute a modest carbon tax to reduce carbon emissions, finance clean energy technology development, cut taxes, and reduce the deficit

    Energy Technology Data Exchange (ETDEWEB)

    Muro, Mark; Rothwell, Jonathan

    2012-11-15

    The nation should institute a modest carbon tax in order to help clean up the economy and stabilize the nation’s finances. Specifically, Congress and the president should implement a $20 per ton, steadily increasing carbon excise fee that would discourage carbon dioxide emissions while shifting taxation onto pollution, financing energy efficiency (EE) and clean technology development, and providing opportunities to cut taxes or reduce the deficit. The net effect of these policies would be to curb harmful carbon emissions, improve the nation’s balance sheet, and stimulate job-creation and economic renewal.

  19. Cleaning of diamond nanoindentation probes with oxygen plasma and carbon dioxide snow

    International Nuclear Information System (INIS)

    Diamond nanoindentation probes may perform thousands of indentations over years of service life. There is a broad agreement that the probes need frequent cleaning, but techniques for doing so are mostly anecdotes shared between experimentalists. In preparation for the measurement of the shape of a nanoindentation probe by a scanning probe microscope, cleaning by carbon dioxide snow jets and oxygen plasma was investigated. Repeated indentation on a thumbprint-contaminated surface formed a compound that was very resistant to removal by solvents, CO2 snow, and plasma. CO2 snow cleaning is found to be a generally effective cleaning procedure.

  20. Method and device for secure, high-density tritium bonded with carbon

    Science.gov (United States)

    Wertsching, Alan Kevin; Trantor, Troy Joseph; Ebner, Matthias Anthony; Norby, Brad Curtis

    2016-04-05

    A method and device for producing secure, high-density tritium bonded with carbon. A substrate comprising carbon is provided. A precursor is intercalated between carbon in the substrate. The precursor intercalated in the substrate is irradiated until at least a portion of the precursor, preferably a majority of the precursor, is transmutated into tritium and bonds with carbon of the substrate forming bonded tritium. The resulting bonded tritium, tritium bonded with carbon, produces electrons via beta decay. The substrate is preferably a substrate from the list of substrates consisting of highly-ordered pyrolytic graphite, carbon fibers, carbon nanotunes, buckministerfullerenes, and combinations thereof. The precursor is preferably boron-10, more preferably lithium-6. Preferably, thermal neutrons are used to irradiate the precursor. The resulting bonded tritium is preferably used to generate electricity either directly or indirectly.

  1. Carbon-carbon bond cleavage and rearrangement of benzene by a trinuclear titanium hydride

    Science.gov (United States)

    Hu, Shaowei; Shima, Takanori; Hou, Zhaomin

    2014-08-01

    The cleavage of carbon-carbon (C-C) bonds by transition metals is of great interest, especially as this transformation can be used to produce fuels and other industrially important chemicals from natural resources such as petroleum and biomass. Carbon-carbon bonds are quite stable and are consequently unreactive under many reaction conditions. In the industrial naphtha hydrocracking process, the aromatic carbon skeleton of benzene can be transformed to methylcyclopentane and acyclic saturated hydrocarbons through C-C bond cleavage and rearrangement on the surfaces of solid catalysts. However, these chemical transformations usually require high temperatures and are fairly non-selective. Microorganisms can degrade aromatic compounds under ambient conditions, but the mechanistic details are not known and are difficult to mimic. Several transition metal complexes have been reported to cleave C-C bonds in a selective fashion in special circumstances, such as relief of ring strain, formation of an aromatic system, chelation-assisted cyclometallation and β-carbon elimination. However, the cleavage of benzene by a transition metal complex has not been reported. Here we report the C-C bond cleavage and rearrangement of benzene by a trinuclear titanium polyhydride complex. The benzene ring is transformed sequentially to a methylcyclopentenyl and a 2-methylpentenyl species through the cleavage of the aromatic carbon skeleton at the multi-titanium sites. Our results suggest that multinuclear titanium hydrides could serve as a unique platform for the activation of aromatic molecules, and may facilitate the design of new catalysts for the transformation of inactive aromatics.

  2. Olefin metathesis for effective polymer healing via dynamic exchange of strong carbon-carbon bonds

    Science.gov (United States)

    Guan, Zhibin; Lu, Yixuan

    2015-09-15

    A method of preparing a malleable and/or self-healing polymeric or composite material is provided. The method includes providing a polymeric or composite material comprising at least one alkene-containing polymer, combining the polymer with at least one homogeneous or heterogeneous transition metal olefin metathesis catalyst to form a polymeric or composite material, and performing an olefin metathesis reaction on the polymer so as to form reversible carbon-carbon double bonds in the polymer. Also provided is a method of healing a fractured surface of a polymeric material. The method includes bringing a fractured surface of a first polymeric material into contact with a second polymeric material, and performing an olefin metathesis reaction in the presence of a transition metal olefin metathesis catalyst such that the first polymeric material forms reversible carbon-carbon double bonds with the second polymeric material. Compositions comprising malleable and/or self-healing polymeric or composite material are also provided.

  3. Plasma Cleaning

    Science.gov (United States)

    Hintze, Paul E.

    2016-01-01

    NASA's Kennedy Space Center has developed two solvent-free precision cleaning techniques: plasma cleaning and supercritical carbon dioxide (SCCO2), that has equal performance, cost parity, and no environmental liability, as compared to existing solvent cleaning methods.

  4. Mechanical Properties of Low-Density SiC-Coated Carbon-Bonded Carbon Fiber Composites

    Czech Academy of Sciences Publication Activity Database

    Ahmed, A. S.; Chlup, Zdeněk; Dlouhý, Ivo; Rawlings, R. D.; Boccaccini, A. R.

    2012-01-01

    Roč. 9, č. 2 (2012), s. 401-412. ISSN 1546-542X R&D Projects: GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : SiC coating * Carbon bonded * Carbon Fiber Composites * Fracture Toughness Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.153, year: 2012

  5. Laser cleaning of diagnostic mirrors from tokamak-like carbon contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Maffini, A., E-mail: alessandro.maffini@polimi.it [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Uccello, A. [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Dellasega, D. [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Milan (Italy); Russo, V. [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Perissinotto, S. [Center for Nano Science and Technology @ Polimi, Istituto Italiano di Tecnologia, Milan (Italy); Passoni, M. [Dipartimento di Energia, Politecnico di Milano, Milan (Italy); Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Milan (Italy)

    2015-08-15

    This paper presents a laboratory-scale experimental investigation of laser cleaning of diagnostic First Mirrors (FMs). Redeposition of contaminants sputtered from tokamak first wall onto FMs surface could dramatically decrease their reflectivity in an unacceptable way for the functioning of the plasma diagnostic systems. Laser cleaning is a promising solution to tackle this issue. In this work, pulsed laser deposition was exploited to produce rhodium films functional as FMs and to deposit onto them carbon contaminants with tailored features, resembling those found in tokamaks. The same laser system was also used to perform laser cleaning experiments by means of a sample handling procedure that allows to clean some cm{sup 2} in few minutes. The cleaning effectiveness was evaluated in terms of specular reflectivity recovery and mirror surface integrity. The effect of different laser wavelengths (λ = 1064, 266 nm) on the cleaning process is also addressed.

  6. Laser cleaning of diagnostic mirrors from tokamak-like carbon contaminants

    International Nuclear Information System (INIS)

    This paper presents a laboratory-scale experimental investigation of laser cleaning of diagnostic First Mirrors (FMs). Redeposition of contaminants sputtered from tokamak first wall onto FMs surface could dramatically decrease their reflectivity in an unacceptable way for the functioning of the plasma diagnostic systems. Laser cleaning is a promising solution to tackle this issue. In this work, pulsed laser deposition was exploited to produce rhodium films functional as FMs and to deposit onto them carbon contaminants with tailored features, resembling those found in tokamaks. The same laser system was also used to perform laser cleaning experiments by means of a sample handling procedure that allows to clean some cm2 in few minutes. The cleaning effectiveness was evaluated in terms of specular reflectivity recovery and mirror surface integrity. The effect of different laser wavelengths (λ = 1064, 266 nm) on the cleaning process is also addressed

  7. Bonding effectiveness of self-adhesive and conventional-type adhesive resin cements to CAD/CAM resin blocks. Part 2: Effect of ultrasonic and acid cleaning.

    Science.gov (United States)

    Kawaguchi, Asuka; Matsumoto, Mariko; Higashi, Mami; Miura, Jiro; Minamino, Takuya; Kabetani, Tomoshige; Takeshige, Fumio; Mine, Atsushi; Yatani, Hirofumi

    2016-01-01

    The present study assessed the effect of ultrasonic and acid cleaning on resin cement bonding to CAD/CAM resin blocks. One of two resin cements, PANAVIA V5 (PV5) or PANAVIA SA CEMENT HANDMIX (PSA), were bonded to one of 24 CAD/CAM blocks (KATANA AVENCIA BLOCK). Each cement group was divided into four subgroups: no cleaning (Ctl), ultrasonic cleaning (Uc), acid cleaning (Ac) and Uc+Ac. Micro-tensile bond strengths (µTBSs) were measured immediately and 1, 3, and 6 months after water storage. Block surfaces after each treatment were analyzed by scanning electron microscopy. Analysis of variance revealed a statistically significant effect for the parameters 'surface treatment' (psandblasting was effective in removing residual alumina particles, it did not affect the long-term bonding durability with non-contaminated CAD/CAM resin blocks. PMID:26830822

  8. Effects of cleaning agents on bond strength to dentin Efeitos de agentes de limpeza na resistência adesiva à dentina

    OpenAIRE

    Celso Rosin; Victor Elias Arana-Chavez; Narciso Garone Netto; Maria Aparecida Alves de Cerqueira Luz

    2005-01-01

    The cleaning of cavity walls aims to improve adhesive restorative procedures and longevity of restorations. This study has compared the effect of three cleaning agents - sodium bicarbonate jet (Profi II, Dabi Atlante, São Paulo, Brazil); pumice paste plus a biologic detergent (Tergestesim, Probem, São Paulo, Brazil); air water spray - on the bond strength between dentin and two different adhesive systems: Clearfil SE Bond (Kuraray, Kioto, Japan) and Scotchbond Multi-Purpose Plus (3M-ESPE, São...

  9. Control of cavitation density through gas and acoustic uniformity in a proximity megasonic pre-bond cleaning system

    Science.gov (United States)

    Dussault, D.; Liebscher, E.; Fournell, F.; Dragoi, V.

    2013-05-01

    A pre-bond cleaning process was developed utilizing a unique, radially uniform, large area proximity type Megasonic transducer. In prior work this new cleaning method was investigated for PRE (particle removal efficiency) as well as particle neutrality. These tests yielded higher values than those achieved with the processes of record. Subsequently, this process was integrated into an industrial volume low temperature fusion bonding process and enabled higher bonding yields. In the above process flow the process fluid was dispensed to fill the gap between the Megasonic transducer surface and the substrate using an atmospheric free flow stream applied to the substrate. Current work describes development, testing and operational verification of a process fluid management device used in conjunction with the wide area proximity Megasonic transducer. The goals of this development were reduction of process fluid amount required, increase the operating substrate rotation speed, and provide better control of process fluid parameters. The design criteria and process flow as well as test results demonstrating the benefits of the new system are presented.

  10. India’s Carbon Governance: The Clean Development Mechanism

    OpenAIRE

    Moniz, Maria da Graça Canto

    2013-01-01

    Carbon Governance systems – institutional arrangements in place for mitigating greenhouse gas emissions – are different in emerging countries. Indeed, carbon is the same everywhere but Carbon Governance isn’t: in Brazil, the financial community is actively interested in carbon trading, but Chinese banks have hardly any interest in it; and while the Chinese government takes an active interest in providing capacity to project developers, the Brazilian authorities see their role uniquely as guar...

  11. RF plasma cleaning of optical surfaces: A study of cleaning rates on different carbon allotropes as a function of RF powers and distances

    CERN Document Server

    Cuxart, M González; Šics, I; Goñi, A R; Fernandez, H Moreno; Carlino, V; Pellegrin, E

    2015-01-01

    An extended study on an advanced method for the cleaning of carbon contaminations on large optical surfaces using a remote inductively coupled low pressure RF plasma source (GV10x downstream asher) is reported in this work. Technical as well as scientific features of this scaled up cleaning process are analyzed, such as the cleaning efficiency for different carbon allotropes (amorphous and diamond-like carbon) as a function of feedstock gas composition, RF power (ranging from 30 to 300W), and source-object distances (415 to 840 mm). The underlying physical phenomena for these functional dependences are discussed.

  12. Study of the damaging mechanisms of a carbon - carbon composite bonded to copper under thermomechanical loading

    International Nuclear Information System (INIS)

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM 2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterisation. (author)

  13. Structure, hydrogen bonding and thermal expansion of ammonium carbonate monohydrate.

    Science.gov (United States)

    Fortes, A Dominic; Wood, Ian G; Alfè, Dario; Hernández, Eduardo R; Gutmann, Matthias J; Sparkes, Hazel A

    2014-12-01

    We have determined the crystal structure of ammonium carbonate monohydrate, (NH4)2CO3·H2O, using Laue single-crystal diffraction methods with pulsed neutron radiation. The crystal is orthorhombic, space group Pnma (Z = 4), with unit-cell dimensions a = 12.047 (3), b = 4.453 (1), c = 11.023 (3) Å and V = 591.3 (3) Å(3) [ρcalc = 1281.8 (7) kg m(-3)] at 10 K. The single-crystal data collected at 10 and 100 K are complemented by X-ray powder diffraction data measured from 245 to 273 K, Raman spectra measured from 80 to 263 K and an athermal zero-pressure calculation of the electronic structure and phonon spectrum carried out using density functional theory (DFT). We find no evidence of a phase transition between 10 and 273 K; above 273 K, however, the title compound transforms first to ammonium sesquicarbonate monohydrate and subsequently to ammonium bicarbonate. The crystallographic and spectroscopic data and the calculations reveal a quite strongly hydrogen-bonded structure (EHB ≃ 30-40 kJ mol(-1)), on the basis of H...O bond lengths and the topology of the electron density at the bond critical points, in which there is no free rotation of the ammonium cation at any temperature. The barrier to free rotation of the ammonium ions is estimated from the observed librational frequency to be ∼ 36 kJ mol(-1). The c-axis exhibits negative thermal expansion, but the thermal expansion behaviour of the a and b axes is ormal. PMID:25449618

  14. Bump Bonding Using Metal-Coated Carbon Nanotubes

    Science.gov (United States)

    Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

    2012-01-01

    Bump bonding hybridization techniques use arrays of indium bumps to electrically and mechanically join two chips together. Surface-tension issues limit bump sizes to roughly as wide as they are high. Pitches are limited to 50 microns with bumps only 8-14 microns high on each wafer. A new process uses oriented carbon nanotubes (CNTs) with a metal (indium) in a wicking process using capillary actions to increase the aspect ratio and pitch density of the connections for bump bonding hybridizations. It merges the properties of the CNTs and the metal bumps, providing enhanced material performance parameters. By merging the bumps with narrow and long CNTs oriented in the vertical direction, higher aspect ratios can be obtained if the metal can be made to wick. Possible aspect ratios increase from 1:1 to 20:1 for most applications, and to 100:1 for some applications. Possible pitch density increases of a factor of 10 are possible. Standard capillary theory would not normally allow indium or most other metals to be drawn into the oriented CNTs, because they are non-wetting. However, capillary action can be induced through the ability to fabricate oriented CNT bundles to desired spacings, and the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. This hybridization of two technologies (indium bumps and CNTs) may also provide for some additional benefits such as improved thermal management and possible current density increases.

  15. Biotic and abiotic carbon to sulfur bond cleavage. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.W.

    1994-05-01

    The microbial desulfurization of organosulfur compounds occurs by unprecedented and largely unexplored biochemical processes. A study of such biotic desulfurizations can be expected to give rise to new and useful chemistry and enzymology. The potential value of understanding and harnessing these processes is seen in relation to the need for methods for the removal of organically bound sulfur from coal and the degradation of organic sulfur-containing pollutants. This research effort has been directed towards an examination of desulfurization ability in well characterized microorganisms, the isolation of bacteria with desulfurization ability from natural sources, the characterization and mechanistic evaluation of the observed biocatalytic processes, the development of biomimetic synthetic organic chemistry based on biotic desulfurization mechanisms and the design and preparation of improved coal model compounds for use in microbial selection processes. A systematic approach to studying biodesulfurizations was undertaken in which organosulfur compounds have been broken down into classes based on the oxidation state of the sulfur atom and the structure of the rest of the organic material. Microbes have been evaluated in terms of ability to degrade organosulfur compounds with sulfur in its sulfonic acid oxidation state. These compounds are likely intermediates in coal desulfurization and are present in the environment as persistent pollutants in the form of detergents. It is known that oxygen bonded to sulfur lowers the carbon-sulfur bond energy, providing a thermodynamic basis for starting with this class of compounds.

  16. Clean energy firms’ stock prices, technology, oil prices, and carbon price

    OpenAIRE

    Mara Madaleno; Alfredo Marvão Pereira

    2015-01-01

    Production costs of alternative energies are still high, but increased demand for oil, future oil supply shortage concerns and climate change concerns, have led to the fast development of renewable energy firms. The sector accomplished has accomplished remarkable progress and attracted attention to clean energy, both at the industry level and at the academic side. With this work we attempt to determine whether or not the placement of a price on carbon emissions encourages investments in clean...

  17. Energy Efficient Indoor VOC Air Cleaning with Activated Carbon Fiber (ACF) Filters

    OpenAIRE

    Sidheswaran, Meera

    2012-01-01

    This study explores the potential environmental and energy benefits of using activated carbon fiber (ACF) filters for air cleaning in HVAC systems. The parallel aims for the air cleaning system were to enable reduced indoor exposures to volatile organic compounds (VOCs) and to simultaneously allow reduced rates and energy consumption for outdoor-air ventilation. We evaluated the use of ACF media to adsorb VOCs from indoor air during repeated simulated 12-hour to 24-hour periods of occupancy. ...

  18. Bond lengths differences between the mollusk-made and geological calcium carbonate

    International Nuclear Information System (INIS)

    We used high-resolution neutron powder diffraction technique in order to accurately measure the atomic positions and bond lengths in calcium carbonates of biogenic (mollusk-made) and geological origin. As a result, in biogenic calcium carbonate we identified atomic bonds, first of all the C-O bonds and some O-O bonds, which obey significant modification (about 1%) with respect to those in geological calcium carbonate. Bond length changes are presumably due to the organic/inorganic interactions in natural bio-composites. Generally, the effect is more pronounced for aragonite, which is structurally more flexible (nine unfixed parameters in atomic positions) than calcite (one parameter of this kind only). The observed bond modifications can be a source of the reported changes in the frequencies of normal vibrations of the carbonate groups measured by Raman or Fourier-transform infrared spectroscopy (FTIR) techniques.

  19. Exploring the uranyl organometallic chemistry: from single to double uranium carbon bonds

    International Nuclear Information System (INIS)

    Uranyl organometallic complexes featuring uranium(VI) carbon single and double bonds have been obtained from uranyl UO2X2 precursors by avoiding reduction of the metal center. X-ray diffraction and density functional theory analyses of these complexes showed that the UC and UdC bonds are polarized toward the nucleophilic carbon. (authors)

  20. Practical carbon-carbon bond formation from olefins through nickel-catalyzed reductive olefin hydrocarbonation.

    Science.gov (United States)

    Lu, Xi; Xiao, Bin; Zhang, Zhenqi; Gong, Tianjun; Su, Wei; Yi, Jun; Fu, Yao; Liu, Lei

    2016-01-01

    New carbon-carbon bond formation reactions expand our horizon of retrosynthetic analysis for the synthesis of complex organic molecules. Although many methods are now available for the formation of C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds via transition metal-catalyzed cross-coupling of alkyl organometallic reagents, direct use of readily available olefins in a formal fashion of hydrocarbonation to make C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds remains to be developed. Here we report the discovery of a general process for the intermolecular reductive coupling of unactivated olefins with alkyl or aryl electrophiles under the promotion of a simple nickel catalyst system. This new reaction presents a conceptually unique and practical strategy for the construction of C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds without using any organometallic reagent. The reductive olefin hydrocarbonation also exhibits excellent compatibility with varieties of synthetically important functional groups and therefore, provides a straightforward approach for modification of complex organic molecules containing olefin groups. PMID:27033405

  1. A New Paradigm for Carbon-Carbon Bond Formation: Aerobic, Copper-Templated Cross-Coupling

    OpenAIRE

    Villalobos, Janette M.; Srogl, Jiri; Liebeskind, Lanny S.

    2007-01-01

    Thiol esters and boronic acids react to produce ketones under aerobic conditions in the presence of catalytic quantities of a CuI or CuII salt. The reaction occurs at reasonable rates between room temperature and 50 °C at neutral pH using thiol esters derived from bulky 2° amides of thiosalicylamides such as those based on N-tert-butyl-2-mercaptobenzamide. In this mechanistically unprecedented reaction system the carbon-carbon bond formation occurs through templating of the thiol ester and th...

  2. Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

    Institute of Scientific and Technical Information of China (English)

    郭锋; 林勤; 孙学义

    2004-01-01

    Electrochemistry experiments were made on carbon-manganese clean steel with rare earths Ce and La respectively to observe corrosion parameters such as corrosion current icorr, and characteristic potential of pitting Eb. The results indicate that the rare earths have effect on corrosion resisting properties of carbon-manganese clean steel, and the optimum contents of La is about 0.011% (mass fraction) and Ce about 0.014% (mass fraction) respectively. The change of corrosion resistance is related to the action of rare earths on microstructure and effect on surface state of samples in the process of polarization.

  3. Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide

    Science.gov (United States)

    Hintze, Paul E.; Muscatello, Anthony C.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.; Bauer, Brint; Parks, Steve

    2016-01-01

    Oxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon, is capable of recovering all the oxygen from carbon dioxide, and it is a promising alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon, and the resulting carbon buildup eventually fouls the catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating one of the designs.

  4. A dense and strong bonding collagen film for carbon/carbon composites

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Sheng; Li, Hejun, E-mail: lihejun@nwpu.edu.cn; Li, Kezhi; Lu, Jinhua; Zhang, Leilei

    2015-08-30

    Graphical abstract: - Highlights: • Significantly enhancement of biocompatibility on C/C composites by preparing a collagen film. • The dense and continuous collagen film had a strong bonding strength with C/C composites after dehydrathermal treatment (DHT) crosslink. • Numerous oxygen-containing functional groups formed on the surface of C/C composites without matrix damage. - Abstract: A strong bonding collagen film was successfully prepared on carbon/carbon (C/C) composites. The surface conditions of the modified C/C composites were detected by contact angle measurements, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectra. The roughness, optical morphology, bonding strength and biocompatibility of collagen films at different pH values were detected by confocal laser scanning microscope (CLSM), universal test machine and cytology tests in vitro. After a 4-h modification in 30% H{sub 2}O{sub 2} solution at 100 °C, the contact angle on the surface of C/C composites was decreased from 92.3° to 65.3°. Large quantities of hydroxyl, carboxyl and carbonyl functional groups were formed on the surface of the modified C/C composites. Then a dense and continuous collagen film was prepared on the modified C/C substrate. Bonding strength between collagen film and C/C substrate was reached to 8 MPa level when the pH value of this collagen film was 2.5 after the preparing process. With 2-day dehydrathermal treatment (DHT) crosslinking at 105 °C, the bonding strength was increased to 12 MPa level. At last, the results of in vitro cytological test showed that this collagen film made a great improvement on the biocompatibility on C/C composites.

  5. Direct synthesis of sp-bonded carbon chains on graphite surface by femtosecond laser irradiation

    International Nuclear Information System (INIS)

    Microscopic phase transformation from graphite to sp-bonded carbon chains (carbyne) and nanodiamond has been induced by femtosecond laser pulses on graphite surface. UV/surface enhanced Raman scattering spectra and x-ray photoelectron spectra displayed the local synthesis of carbyne in the melt zone while nanocrystalline diamond and trans-polyacetylene chains form in the edge area of gentle ablation. These results evidence possible direct 'writing' of variable chemical bonded carbons by femtosecond laser pulses for carbon-based applications

  6. DEMONSTRATION OF A LIQUID CARBON DIOXIDE PROCESS FOR CLEANING METAL PARTS

    Science.gov (United States)

    The report gives results of a demonstration of liquid carbon dioxide (LCO2) as an alternative to chlorinated solvents for cleaning metal parts. It describes the LCO2 process, the parts tested, the contaminants removed, and results from preliminary laboratory testing and on-site d...

  7. Compatibility studies on carbon steel and Monel-400 in steam generator cleaning formulations

    International Nuclear Information System (INIS)

    EDTA based Steam Generator (SG) cleaning formulations are being used worldwide to remove the sludge accumulated on tubes, tube sheets and the baffle plates of the tubes in steam generators. In early Indian PHWRs, SG shells are made up of carbon steel and the tubes are made of Monel-400. Corrosion compatibility of carbon steel and Monel-400 in SG cleaning formulations were evaluated so as to assess the suitability of these formulations for cleaning the steam generators. SG cleaning iron formulation contains 10% EDTA at pH 6 (pH additive NH3) along with 1% hydrazine. These experiments were carried out at 95 degC under inert condition. The SG cleaning copper formulation consists of 5% EDTA at pH 9.5 (pH adjusted by EDA) and 2% hydrogen peroxide. These experiments were conducted at room temperature. Further, experiments were carried out to study the effect of oxygen, the effect of pH additives namely NH3, EDA and NaOH, effect of presence of Fe3+ ions, effect of roughening of the surface on corrosion rate of carbon steel. The role of hydrazine and effect of decomposed products of EDTA on corrosion of carbon steel were also studied. Elaborate study was done on specimens that were prepared by cold-rolling and hot-rolling. Inhibitors like Rodine-92B and some non-sulphur inhibitors such as 1,2,3 benzotriazole, hexynols etc. were tested to determine their inhibition efficiency on corrosion of carbon steel. Microscopic observations on the exposed specimens were done to observe any localised attack. (author)

  8. Development and characterization of carbon-bonded carbon fiber insulation for radioisotope space power systems

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G.C.; Robbins, J.M.

    1985-06-01

    The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W(m.K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF superior to other known high-temperature insulation materials for the GPHS application have been identified. It has the excellent attributes of light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the GPHS application; it has passed vibration tests simulating launch conditions. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to incease the fabrication rate by a factor of 10. The specific properties of the CBCF were tailored by adjusting material and processing variables to obtain the desired results. We report here how work on CBCF characterization and development conducted at ORNL from 1978 through 1980 has contributed to the GPHS program to meet the requirements of both the Galileo and Ulysees Missions.

  9. Degradation of Perfluorotrichlorosilane Antisticking Layers: The Impact on Mold Cleaning, Ultraviolet-Nanoimprinting, and Bonded Ultraviolet-Nanoimprint Molds

    Science.gov (United States)

    Kirchner, Robert; Teng, Lichao; Lu, Bo; Adolphi, Barbara; Fischer, Wolf-Joachim

    2011-06-01

    A reduction of the adhesion between imprint resist and mold is crucial for defect free imprints and is commonly achieved by silane based antisticking layers. Highly stable antisticking layers are required for high throughputs and long imprint mold lifetimes. Hybrid nanoimprint molds avoid the imprint inherent residual polymer layer in UV-assisted nanoimprinting. Such hybrid molds have chemically heterogeneous surfaces of silica and, e.g., chromium oxide regions. The chemical stability of vapor-coated 1H,1H,2H,2H-perfluorodecyltrichlorosilane antisticking layers against acetone, acidic piranha, reactive ion etching and UV-assisted nanoimprinting was investigated. To evaluate the behavior of hybrid mold surfaces, flat silica and antireflective chromium-oxynitride surfaces were used. The antisticking layer on both surfaces was highly chemical resistant against acetone. A continuous antisticking layer degradation with a surface free energy increase of 0.9 mN/m per 10 min piranha treatment and 1.2 mN/m per 10 subsequent UV-assisted imprints was found for silica surfaces. On the chromium surfaces, the antisticking layer quality was much lower than on fused silica and degraded much faster. The surface free energy of silane coated chromium surfaces was increased by 2.3 mN/m after 10 imprints and the antisticking layer was completely degraded after a single 10 min piranha cleaning step. The lower antisticking layer quality on antireflective chromium was attributed to the surface itself. Additionally, the high chemical resistance of the vapor coated silane was used to successfully protect the adhesive joints of cost-efficient, adhesively bonded nanoimprint molds from being degraded by acidic piranha during mold cleaning. This can significantly increase the life-time of such bonded molds.

  10. Low carbon Finland 2050. VTT clean energy technology strategies for society

    Energy Technology Data Exchange (ETDEWEB)

    Koljonen, T.; Simila, L.; Sipila, K. [and others

    2012-11-15

    The Low Carbon Finland 2050 project by VTT Technical Research Centre of Finland aims to assess the technological opportunities and challenges involved in reducing Finland's greenhouse gas emissions. A target for reduction is set as at least 80% from the 1990 level by 2050 as part of an international effort, which requires strong RD and D in clean energy technologies. Key findings of the project are presented in this publication, which aims to stimulate enlightening and multidisciplinary discussions on low-carbon futures for Finland. The project gathered together VTT's technology experts in clean energy production, smart energy infrastructures, transport, buildings, and industrial systems as well as experts in energy system modelling and foresight. VTT's leading edge 'Low Carbon and Smart Energy' enables new solutions with a demonstration that is the first of its kind in Finland, and the introduction of new energy technology onto national and global markets. (orig.)

  11. Bonding strength in carbon steel sandwich panels under condition of diffusion-rolling with small reduction

    Institute of Scientific and Technical Information of China (English)

    LIU Jing; HAN Jing-tao; FU Ding-mei

    2005-01-01

    One of the key problems by diffusion-rolling bonding with small reduction for carbon steel plates is the bonding assistant coat. A bonding assistant coat used below 850 ℃ was developed. It contained copper as basic element and zinc as main alloy element. Other small elements and rare metals were added to decrease the melting point and to obtain a better clouding and high plasticity. Based on the theory of brazing and transient liquid diffusion welding, two carbon steel plates were rolled with small reduction by using self-made bonding assistant coat. Temperature, pressure and holding time are the main technology parameters for controlling the process of diffusion-rolling. The results show that the bonding strength is the greatest when the bonding temperature is 830 ℃, holding time is 3 min and the reduction rate is 9%.

  12. Ethenolysis: A Green Catalytic Tool to Cleave Carbon-Carbon Double Bonds.

    Science.gov (United States)

    Bidange, Johan; Fischmeister, Cédric; Bruneau, Christian

    2016-08-22

    Remarkable innovations have been made in the field of olefin metathesis due to the design and preparation of new catalysts. Ethenolysis, which is cross-metathesis with ethylene, represents one catalytic transformation that has been used with the purpose of cleaving internal carbon-carbon double bonds. The objectives were either the ring opening of cyclic olefins to produce dienes or the shortening of unsaturated hydrocarbon chains to degrade polymers or generate valuable shorter terminal olefins in a controlled manner. This Review summarizes several aspects of this reaction: the catalysts, their degradation in the presence of ethylene, some parameters driving their productivity, the side reactions, and the applications of ethenolysis in organic synthesis and in potential industrial applications. PMID:27359344

  13. Characterization of carbon-sulfur bond cleavage by axenic and mixed cultures of Rhodococcus rhodochrous IGTS8

    Energy Technology Data Exchange (ETDEWEB)

    Kayser, K.J.; Bielaga, B.A.; Jackowski, K.; Oduson, O.; Kilbane, J. II

    1992-12-31

    Growth assays reveal that Rhodococcus rhodochrous IGTS8 can utilize a wide range of organosulfur compounds as the sole source of sulfur. Compounds that are utilized include thiophenes, sulfides, disulfides, mercaptans, sulfoxides, and sulfones. None of the organosulfur compounds tested can serve as a carbon source. A convenient spectrophotometric assay (Gibbs assay) based on the chromogenic reaction of 2,6-dichloroquinone-4-chloroimide with aromatic hydroxyl groups was developed and used in conjunction with GC/MS analysis to examine the kinetics of carbon-sulfur bond cleavage by axenic and mixed cell cultures of Rhodococcus rhodochrous IGTS8. The desulfurization trait is expressed at uniform levels during the mid-exponential phase, reaches a maximum during idiophase, and then declines in stationary-phase cells. Desulfurization rates for dibenzothiophene (DBT) range from 8 to 15 {mu}M of DBT/10{sup 12} cells/hour. Mixtures of genetically marked Rhodococcus rhodochrous IGTS8 and an organisms incapable of cleaning carbon-sulfur bonds in relevant test compounds, Enterobacter cloacae, were prepared in ratios that varied over six orders of magnitude. Growth studies revealed that Enterobacter cloacae was able to gain access to sulfur liberated from organosulfur compounds by IGTS8; however, cell-to-cell contact was required. These data also indicate that the desulfurization activity of IGTS8 cells in mixed cultures may be as much as 200-fold higher than in axenic cultures.

  14. Trifluoromethylallylation of Heterocyclic C-H Bonds with Allylic Carbonates under Rhodium Catalysis.

    Science.gov (United States)

    Choi, Miji; Park, Jihye; Sharma, Satyasheel; Jo, Hyeim; Han, Sangil; Jeon, Mijin; Mishra, Neeraj Kumar; Han, Sang Hoon; Lee, Jong Suk; Kim, In Su

    2016-06-01

    The rhodium(III)-catalyzed γ-trifluoromethylallylation of various heterocyclic C-H bonds with CF3-substituted allylic carbonates is described. These reactions provide direct access to linear CF3-containing allyl frameworks with complete trans-selectivity via C-H bond activation followed by a formal SN-type reaction pathway. PMID:27187625

  15. Outgassing behavior of carbon-bonded carbon-fiber thermal insulation

    International Nuclear Information System (INIS)

    A carbon-bonded carbon-fiber (CBCF3) thermal insulation has been developed and has demonstrated acceptable strength, thermal conductivity, and outgassing properties for the Selenide Isotope Generator. Primary outgassing at 13500C and 0.1 mPa (10-6 torr) for 70 h seems satisfactory because reabsorption during exposure to argon or air is minimal and the total weight loss during secondary outgassing is also very small. The total outgassing of CBCF3 insulation during generator start-up and operation is equivalent to the weight loss during secondary outgassing, (i.e., 0.08 mg per gram of CBCF3 insulation). The dominating gaseous species of secondary outgassing are CO and CO2. Primary outgassing [13500C at 0.1 mPa (10-6 torr) for 70 h] causes no increases in the thermal conductivity of CBCF3 insulation. Specimen size affects the first few hours of primary outgassing and thus the fraction of total amount of volatile species being driven off at the end of primary outgassing. However, the time required to outgas a large specimen does not vary with the square of specimen size because diffusion in each fiber or bond is the rate-determining step of primary outgassing

  16. Engineering de novo disulfide bond in bacterial α-type carbonic anhydrase for thermostable carbon sequestration

    Science.gov (United States)

    Jo, Byung Hoon; Park, Tae Yoon; Park, Hyun June; Yeon, Young Joo; Yoo, Young Je; Cha, Hyung Joon

    2016-01-01

    Exploiting carbonic anhydrase (CA), an enzyme that rapidly catalyzes carbon dioxide hydration, is an attractive biomimetic route for carbon sequestration due to its environmental compatibility and potential economic viability. However, the industrial applications of CA are strongly hampered by the unstable nature of enzymes. In this work, we introduced in silico designed, de novo disulfide bond in a bacterial α-type CA to enhance thermostability. Three variants were selected and expressed in Escherichia coli with an additional disulfide bridge. One of the variants showed great enhancement in terms of both kinetic and thermodynamic stabilities. This improvement could be attributed to the loss of conformational entropy of the unfolded state, showing increased rigidity. The variant showed an upward-shifted optimal temperature and appeared to be thermoactivated, which compensated for the lowered activity at 25 °C. Collectively, the variant constructed by the rapid and effective de novo disulfide engineering can be used as an efficient biocatalyst for carbon sequestration under high temperature conditions. PMID:27385052

  17. TOPICAL REVIEW: Carbon nanotubes for clean energy applications

    Science.gov (United States)

    Liu, Chang; Cheng, Hui-Ming

    2005-07-01

    The issue of the sustainability of energy supply has attracted worldwide concern given the rapid depletion of fossil energy sources amid increasingly worsening environmental pollution and the drive to develop alternative, environment-friendly, renewable energy sources and energy carriers to secure our energy supply and sustainable development. Hydrogen is considered to be among the best solutions available, although technical barriers, in particular effective hydrogen storage, need to be dealt with. Quasi-one-dimensional carbon nanotubes (CNTs) with rich nanosized pore structures are considered to be a potential hydrogen storage medium; however, controversy over and discrepancies in both the experimental and theoretical results do exist. Therefore, the latest research progress in and the current situation pertaining to hydrogen storage in CNTs are reviewed and discussed in detail. Moreover, CNTs can have wide applications as alternative energy storage media, utilizing fully their unique structural characteristics. We summarize and analyse the advantages as well as the research progress made in using CNTs as electrode materials in lithium-ion batteries and supercapacitors. Further, future applications of CNTs in the energy storage field are explored.

  18. Dynamic response of a carbon nanotube-based rotary nano device with different carbon-hydrogen bonding layout

    Science.gov (United States)

    Yin, Hang; Cai, Kun; Wan, Jing; Gao, Zhaoliang; Chen, Zhen

    2016-03-01

    In a nano rotational transmission system (RTS) which consists of a single walled carbon nanotube (SWCNT) as the motor and a coaxially arranged double walled carbon nanotube (DWCNT) as a bearing, the interaction between the motor and the rotor in bearing, which has great effects on the response of the RTS, is determined by their adjacent edges. Using molecular dynamics (MD) simulation, the interaction is analyzed when the adjacent edges have different carbon-hydrogen (Csbnd H) bonding layouts. In the computational models, the rotor in bearing and the motor with a specific input rotational speed are made from the same armchair SWCNT. Simulation results demonstrate that a perfect rotational transmission could happen when the motor and rotor have the same Csbnd H bonding layout on their adjacent ends. If only half or less of the carbon atoms on the adjacent ends are bonded with hydrogen atoms, the strong attraction between the lower speed (100 GHz) motor and rotor leads to a synchronous rotational transmission. If only the motor or the rotor has Csbnd H bonds on their adjacent ends, no rotational transmission happens due to weak interaction between the bonded hydrogen atoms on one end with the sp1 bonded carbon atoms on the other end.

  19. Bonding preference of carbon, nitrogen, and oxygen in niobium-based rock-salt structures.

    Science.gov (United States)

    Miura, Akira; Takei, Takahiro; Kumada, Nobuhiro; Wada, Satoshi; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2013-09-01

    Carbon, nitrogen, and oxygen are essential components in solid-state materials. However, understanding their preference on the bonding to metals has not been straightforward. Here, niobium carbide, nitride, and oxide with simple rock-salt-based structures were analyzed by first-principles calculations and synchrotron X-ray diffraction. We found that an increase in the atomic number from carbon to oxygen formed fewer and shorter bonds to metals with better hybridization of atomic orbitals. This can provide a simple guiding principle for understanding the bonding and designing carbides, nitrides, oxides, and mixed-anion compounds. PMID:23937352

  20. Plasma coating formed TIO2 catalysts usage in cleaning the air from nitrogen oxides and carbon monoxide

    OpenAIRE

    Vitalij Kolodynskij; Pranas Baltrėnas

    2015-01-01

    The present catalytic air purification device–air cleaning device is capable to reduce nitrogen oxide sand carbon monoxide concentrations in polluted air stream and to achieve high cleaning efficiency. The principle of operation of catalytic air cleaning device is based on plasma coating formed catalysts usage. At high temperatures and oxygen concentrations in the experimental device channel, catalysts become active and reactions of conversion of pollutants start. In this research, the effici...

  1. Anion–arene adducts: C–H hydrogen bonding, anion– interaction, and carbon bonding motifs

    OpenAIRE

    Hay, Benjamin P.; Bryantsev, Vyacheslav S.

    2008-01-01

    This article summarizes experimental and theoretical evidence for the existence of four distinct binding modes for complexes of anions with charge-neutral arenes. These include C–H hydrogen bonding and three motifs involving the arene– system—the noncovalent anion– interaction, weakly covalent interaction, and strongly covalent interaction.

  2. Hydrogen bonded complexes of cyanuric acid with pyridine and guanidinium carbonate

    Indian Academy of Sciences (India)

    K Sivashankar

    2000-12-01

    Hydrogen bonded complexes of cyanuric acid (CA) with pyridine, [C3N3H3O3:C5H5N], 1, and guanidinium carbonate [C3H2N3][C(NH2)3], 2, have been prepared at room temperature and characterized by single-crystal X-ray diffraction. Structure of 1 shows pyridine molecules substituting the inter-tape hydrogen bond in CA by N-H…N and C-H…O hydrogen bonds. The structure reveals CA-pyridine hydrogen-bonded single helices held together by dimeric N-H…O hydrogen bonding between CA molecules. In 2, the CA tapes, resembling a sine wave interact with the guanidinium cations through N-H…O and N-H…N hydrogen bonds forming guanidinium cyanurate sheets.

  3. Atomic Structures of Graphene, Benzene and Methane with Bond Lengths as Sums of the Single, Double and Resonance Bond Radii of Carbon

    OpenAIRE

    Heyrovska, Raji

    2008-01-01

    Two dimensional layers of graphene are currently drawing a great attention in fundamental and applied nanoscience. Graphene consists of interconnected hexagons of carbon atoms as in graphite. This article presents for the first time the structures of graphene at the atomic level and shows how it differs from that of benzene, due to the difference in the double bond and resonance bond based radii of carbon. The carbon atom of an aliphatic compound such as methane has a longer covalent single b...

  4. Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide

    Science.gov (United States)

    Coutts, Janelle; Hintze, Paul E.; Muscatello, Anthony C.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.; Bauer, Brint; Parks, Steve

    2016-01-01

    Oxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50 because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon is capable of recovering all the oxygen from carbon dioxide, and is the only real alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon and the resulting carbon buildup will eventually foul the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating one of the designs.

  5. Cathodic carbon peroxidation process. Surface modifications through oxygen bonding

    OpenAIRE

    Simonet, Jacques

    2013-01-01

    The reduction of oxygen of the air at carbon electrodes in organic aprotic polar solvents in the presence of organic electrophiles such as alkyl iodides may reveal the formation of films of surface-attached alkyl peroxides. Electrochemical charge of carbons (glassy carbon, graphite, industrial coke) in the presence of tetraalkylammonium salt TAAX permits the building of poly-nucleophilic materials that may spontaneously react with air during the work up. This way, a TAA+ hydroperoxydate layer...

  6. Sweet carbon: An analysis of sugar industry carbon market opportunities under the clean development mechanism

    International Nuclear Information System (INIS)

    Bagasse power generation projects provide a useful framework for evaluating several key aspects of the Clean Development Mechanism of the Kyoto Protocol. On the positive side, our analysis, which draws in part from a data set of 204 bagasse electricity generation projects at sugar mills, indicates that these projects provide Annex I country investors with a cost-effective means to achieve greenhouse gas emissions reductions. Our analysis also confirms that the marketplace for Clean Development Mechanism-derived offsets is robust and competitive. Moreover, bagasse projects appear to provide a positive example in a 'new wave' of clean energy investment that has replaced the earlier industrial gas projects. At the same time, we also identify two aspects of the CDM that demand improvement. First, the additionality standard needs to be tightened and made more transparent and consistent. Financial additionality should be required for all projects; however, any financial additionality test applied by the Clean Development Mechanism's Executive Board must be informed by the significant barriers faced by many projects. Second, the administrative processes for registration and verification of offsets need to be streamlined in order to prevent long registration time lags from chilling clean energy investment.

  7. Coal cleaning: a viable strategy for reduced carbon emissions and improved environment in China?

    International Nuclear Information System (INIS)

    China is a dominant energy consumer in global context and current energy forecasts emphasise that China's future energy consumption also will rely heavily on coal. The coal use is the major source of the greenhouse gas CO2 and particles causing serious health damage. This paper looks into the question if coal washing might work as low cost strategy for both CO2 and particle emission reductions. Coal washing removes dirt and rock from raw coal, resulting in a coal product with higher thermal energy and less air pollutants. Coal cleaning capacity has so far not been developed in line with the market potential. In this paper an emerging market for cleaned coal is studied within a CGE model for China. The macro approach catches the repercussions of coal cleaning through increased energy efficiency, lower coal transportation costs and crowding out effect of investments in coal washing plants. Coal cleaning stimulates economic growth and reduces particle emissions, but total energy use, coal use and CO2 emissions increase through a rebound effect supported by the vast reserve of underemployed labourers. A carbon tax on fossil fuel combustion has a limited effect on total emissions. The reason is a coal leakage to tax exempted processing industries

  8. Corrosion of carbon steel and Monel-400 in EDTA based steam generator cleaning formulations

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, S.V.; Padma, S.; Veena, S.N.; Rufus, A.L.; Sathyaseelan, V.S.; Velmurugan, S. [Water and Steam Chemistry Lab., BARC Facilities Kalpakkam, Tamilnadu (India)

    2001-10-01

    Corrosion products and the scale forming impurities foul the steam generators of pressurized water reactors (PWR) and pressurized heavy water reactors (PHWR). The impurities from the make-up water, the condenser leaks and the corrosion product oxides leached from the feed train structural materials are carried along with the feed water and concentrate in the steam generators. These impurities deposit/precipitate over the steam generator surfaces and cause several problems such as reduction in heat transfer efficiency, under deposit attack, tube failures and production loss. In order to solve this problem, the power utilities are resorting increasingly to chemical cleaning of the steam generators. The chemical formulation selected for cleaning should be able to dissolve the accumulated corrosion products/sludge and at the same time should be compatible with the steam generator structural materials. Of the various chemical-cleaning formulations, the EDTA based formulations are more popular and have been used in the chemical cleaning of many nuclear steam generators. Its corrosion compatibility with the structural-materials of the steam generators needs a thorough evaluation. In this work, the effect of various additives added to the EDTA such as pH additive, reducing agent, oxidizing agent and corrosion inhibitors have been investigated. Increase in the concentration of hydrazine has been found to increase the corrosion rate of carbon steel. The variation in corrosion release from carbon steel with time was found to fit a second order equation. The variation in corrosion rate with time was attributed entirely to the increase in surface area caused by roughening of the surface. Presence of dissolved oxygen in EDTA based iron formulation enhanced the corrosion rate of carbon steel and pitted the Monel-400. The study indicated the need for strict oxygen control and the necessity of using a suitable corrosion inhibitor during the iron removal step. The role of copper in

  9. Atomic Structures of Graphene, Benzene and Methane with Bond Lengths as Sums of the Single, Double and Resonance Bond Radii of Carbon

    CERN Document Server

    Heyrovska, Raji

    2008-01-01

    Two dimensional layers of graphene are currently drawing a great attention in fundamental and applied nanoscience. Graphene consists of interconnected hexagons of carbon atoms as in graphite. This article presents for the first time the structures of graphene at the atomic level and shows how it differs from that of benzene, due to the difference in the double bond and resonance bond based radii of carbon. The carbon atom of an aliphatic compound such as methane has a longer covalent single bond radius as in diamond. All the atomic structures presented here have been drawn to scale.

  10. Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S.; Grate, Jay W.

    2010-06-01

    Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

  11. SURFACE HYDROPHILIC MODIFICATION FOR CARBON/CARBON COMPOSITES AND ITS EFFECT ON THE BONDING STRENGTH OF HYDROXYAPATITE COATING

    OpenAIRE

    LEILEI ZHANG; HEJUN LI; QIANG SONG; KEZHI LI; JINHUA LU; WEI LI; Mikhalovsky, Sergey V.; SHENG CAO

    2014-01-01

    In order to improve the bonding strength of hydroxyapatite coating on carbon/carbon composites, a surface hydrophilic modification was performed on carbon/carbon composites using a combination of H2O2 and FeSO4 ⋅ 7H2O under ultraviolet irradiation. The hydroxyapatite coating was prepared by an ultrasound-assisted electrochemical deposition method. The results showed that the surface hydrophilic modification introduced a large number of oxygen-containing functional groups (C=O, C–O and COOH gr...

  12. Adhesive bonding of discontinuous carbon fibre composites: an experimental investigation

    OpenAIRE

    Nicholls, Tristan Kit

    2013-01-01

    The excellent specific stiffness and strength of carbon fibre reinforced polymer composites means that the automotive sector has been investigating methods of implementing these materials into structurally demanding applications. The work detailed within this thesis supports ongoing research at the University of Nottingham into the automated manufacture of discontinuous carbon fibre reinforced polymer composite materials. Advances in the automation of composites manufacturing has meant that m...

  13. Effect of cleaning procedures on the electrical properties of carbon nanotube transistors—A statistical study

    Science.gov (United States)

    Tittmann-Otto, J.; Hermann, S.; Kalbacova, J.; Hartmann, M.; Toader, M.; Rodriguez, R. D.; Schulz, S. E.; Zahn, D. R. T.; Gessner, T.

    2016-03-01

    The interface between a carbon nanotube (CNT) and its environment can dramatically affect the electrical properties of CNT-based field-effect transistors (FETs). For such devices, the channel environment plays a significant role inducing doping or charge traps giving rise to hysteresis in the transistor characteristics. Thereby the fabrication process strongly determines the extent of those effects and the final device performance. In CNT-based devices obtained from dispersions, a proper individualization of the nanotubes is mandatory. This is generally realized by an ultrasonic treatment combined with surfactant molecules, which enwrap nanotubes forming micelle aggregates. To minimize impact on device performance, it is of vital importance to consider post-deposition treatments for removal of surfactant molecules and other impurities. In this context, we investigated the effect of several wet chemical cleaning and thermal post treatments on the electrical characteristics as well as physical properties of more than 600 devices fabricated only by wafer-level compatible technologies. We observed that nitric acid and water treatments improved the maximum-current of devices. Additionally, we found that the ethanol treatment successfully lowered hysteresis in the transfer characteristics. The effect of the chemical cleaning procedures was found to be more significant on CNT-metal contacts than for the FET channels. Moreover, we investigated the effect of an additional thermal cleaning step under vacuum after the chemical cleaning, which had an exceptional impact on the hysteresis behavior including hysteresis reversal. The presence of surfactant molecules on CNT was evidenced by X-ray photoelectron and Raman spectroscopies. By identifying the role of surfactant molecules and assessing the enhancement of device performance as a direct consequence of several cleaning procedures, these results are important for the development of CNT-based electronics at the wafer-level.

  14. Closo-Carborane-metal complexes containing metal-carbon and metal-boron sigma-bonds

    International Nuclear Information System (INIS)

    This paper examines the metal derivatives of the closo-carboranes formed through carborane carbon-metal and carborane boron-metal bonds. In order to provide a better perspective of the closo-carborane-metal compounds the authors include derivatives containing carboranyl groups bonded to boron and silicon, which are normally classified as nonmetals. The structures, nomenclature system, and general preparative methods of the closo-carboranes are examined

  15. Financing renewable energy infrastructure: Formulation, pricing and impact of a carbon revenue bond

    International Nuclear Information System (INIS)

    Renewable energy systems depend on large financial incentives to compete with conventional generation methods. Market-based incentives, including state-level REC markets and international carbon markets have been proposed as solutions to increase renewable energy investment. In this paper we introduce and formulate a carbon revenue bond, a financing tool to complement environmental credit markets to encourage renewable energy investment. To illustrate its use, we value the bond by predicting future revenue using stochastic processes after analyzing historical price data. Three illustrative examples are presented for renewable energy development in three different markets: Europe, Australia and New Jersey. Our findings reveal that the sale of a carbon revenue bond with a ten year maturity can finance a significant portion of a project's initial cost. - Highlights: ► Current financial incentives for renewable energy in the US are inadequate. ► We introduce and structure a “carbon revenue bond” as an innovative financing tool. ► Stochastic models of environmental credit prices are used to illustrate bond pricing. ► Three examples illustrate revenue bond impact on initial cost of infrastructure.

  16. Precision Cleaning Verification of Fluid Components by Air/Water Impingement and Total Carbon Analysis

    Science.gov (United States)

    Barile, Ronald G.; Fogarty, Chris; Cantrell, Chris; Melton, Gregory S.

    1995-01-01

    NASA personnel at Kennedy Space Center's Material Science Laboratory have developed new environmentally sound precision cleaning and verification techniques for systems and components found at the center. This technology is required to replace existing methods traditionally employing CFC-113. The new patent-pending technique of precision cleaning verification is for large components of cryogenic fluid systems. These are stainless steel, sand cast valve bodies with internal surface areas ranging from 0.2 to 0.9 m(exp 2). Extrapolation of this technique to components of even larger sizes (by orders of magnitude) is planned. Currently, the verification process is completely manual. In the new technique, a high velocity, low volume water stream impacts the part to be verified. This process is referred to as Breathing Air/Water Impingement and forms the basis for the Impingement Verification System (IVS). The system is unique in that a gas stream is used to accelerate the water droplets to high speeds. Water is injected into the gas stream in a small, continuous amount. The air/water mixture is then passed through a converging-diverging nozzle where the gas is accelerated to supersonic velocities. These droplets impart sufficient energy to the precision cleaned surface to place non-volatile residue (NVR) contaminants into suspension in the water. The sample water is collected and its NVR level is determined by total organic carbon (TOC) analysis at 880 C. The TOC, in ppm carbon, is used to establish the NVR level. A correlation between the present gravimetric CFC-113 NVR and the IVS NVR is found from experimental sensitivity factors measured for various contaminants. The sensitivity has the units of ppm of carbon per mg-ft(exp 2) of contaminant. In this paper, the equipment is described and data are presented showing the development of the sensitivity factors from a test set including four NVR's impinged from witness plates of 0.05 to 0.75 m(exp 2).

  17. Rhodium(i)-catalysed skeletal reorganisation of benzofused spiro[3.3]heptanes via consecutive carbon-carbon bond cleavage.

    Science.gov (United States)

    Matsuda, Takanori; Yuihara, Itaru; Kondo, Kazuki

    2016-08-01

    Skeletal reorganisation of benzofused spiro[3.3]heptanes has been achieved using rhodium(i) catalysts. The reaction of benzofused 2-(2-pyridylmethylene)spiro[3.3]heptanes proceeds via sequential C-C bond oxidative addition and β-carbon elimination. On the other hand, benzofused spiro[3.3]heptan-2-ols undergo two consecutive β-carbon elimination processes. In both cases, substituted naphthalenes are obtained. PMID:27357097

  18. Formation Mechanism of the First Carbon-Carbon Bond and the First Olefin in the Methanol Conversion into Hydrocarbons.

    Science.gov (United States)

    Liu, Yue; Müller, Sebastian; Berger, Daniel; Jelic, Jelena; Reuter, Karsten; Tonigold, Markus; Sanchez-Sanchez, Maricruz; Lercher, Johannes A

    2016-05-01

    The elementary reactions leading to the formation of the first carbon-carbon bond during early stages of the zeolite-catalyzed methanol conversion into hydrocarbons were identified by combining kinetics, spectroscopy, and DFT calculations. The first intermediates containing a C-C bond are acetic acid and methyl acetate, which are formed through carbonylation of methanol or dimethyl ether even in presence of water. A series of acid-catalyzed reactions including acetylation, decarboxylation, aldol condensation, and cracking convert those intermediates into a mixture of surface bounded hydrocarbons, the hydrocarbon pool, as well as into the first olefin leaving the catalyst. This carbonylation based mechanism has an energy barrier of 80 kJ mol(-1) for the formation of the first C-C bond, in line with a broad range of experiments, and significantly lower than the barriers associated with earlier proposed mechanisms. PMID:27037603

  19. The contribution of foreign direct investment to clean energy use, carbon emissions and economic growth

    International Nuclear Information System (INIS)

    The paper investigates the contributions of foreign direct investment (FDI) net inflows to clean energy use, carbon emissions, and economic growth. The paper employs cointegration tests to examine a long-run equilibrium relationship among the variables and fixed effects models to examine the magnitude of FDI contributions to the other variables. The paper analyzes panel data of 19 nations of the G20 from 1971 to 2009. The test results indicate that FDI has played an important role in economic growth for the G20 whereas it limits its impact on an increase in CO2 emissions in the economies. The research finds no compelling evidence of FDI link with clean energy use. Given the results, the paper discusses FDI's potential role in achieving green growth goals. - Highlights: ► FDI inflows strongly lead to economic growth in the G20. ► FDI inflows lead to an increase in energy use in the G20. ► FDI inflows are in no relation to CO2 emissions in the G20. ► FDI inflows are in no relation to clean energy use in the G20. ► Economic growth is in negative relation to CO2 emissions in the G20

  20. Studies of reductive elimination reactions to form carbon-oxygen bonds from Pt(IV) complexes.

    Science.gov (United States)

    Williams, B S; Goldberg, K I

    2001-03-21

    The platinum(IV) complexes fac-L(2)PtMe(3)(OR) (L(2) = bis(diphenylphosphino)ethane, o-bis(diphenylphosphino)benzene, R = carboxyl, aryl; L = PMe(3), R = aryl) undergo reductive elimination reactions to form carbon-oxygen bonds and/or carbon-carbon bonds. The carbon-oxygen reductive elimination reaction produces either methyl esters or methyl aryl ethers (anisoles) and L(2)PtMe(2), while the carbon-carbon reductive elimination reaction affords ethane and L(2)PtMe(OR). Choice of reaction conditions allows the selection of either type of coupling over the other. A detailed mechanistic study of the reductive elimination reactions supports dissociation of the OR(-) ligand as the initial step for the C-O bond formation reaction. This is followed by a nucleophilic attack of OR(-) upon a methyl group bound to the Pt(IV) cation to produce the products MeOR and L(2)PtMe(2). C-C reductive elimination proceeds from L(2)PtMe(3)(OR) by initial L (L = PMe(3)) or OR(-) (L(2) = dppe, dppbz) dissociation, followed by C-C coupling from the resulting five-coordinate intermediate. Our studies demonstrate that both C-C and C-O reductive elimination reactions from Pt(IV) are more facile in polar solvents, in the presence of Lewis acids, and for OR(-) groups that contain electron withdrawing substituents. PMID:11456927

  1. CORROSION TESTING OF CARBON STEEL IN OXALIC ACID CHEMICAL CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.; Mickalonis, J.; Subramanian, K.; Ketusky, E.

    2011-10-14

    Radioactive liquid waste has been stored in underground carbon steel tanks for nearly 60 years at the Savannah River Site. The site is currently in the process of removing the waste from these tanks in order to place it into vitrified, stable state for longer term storage. The last stage in the removal sequence is a chemical cleaning step that breaks up and dissolves metal oxide solids that cannot be easily pumped out of the tank. Oxalic acid has been selected for this purpose because it is an effective chelating agent for the solids and is not as corrosive as other acids. Electrochemical and immersion studies were conducted to investigate the corrosion behavior of carbon steel in simulated chemical cleaning environments. The effects of temperature, agitation, and the presence of sludge solids in the oxalic acid on the corrosion rate and the likelihood of hydrogen evolution were determined. The testing showed that the corrosion rates decreased significantly in the presence of the sludge solids. Corrosion rates increased with agitation, however, the changes were less noticeable.

  2. Computational design of organometallic oligomers featuring 1,3-metal-carbon bonding and planar tetracoordinate carbon atoms.

    Science.gov (United States)

    Zhao, Xue-Feng; Yuan, Cai-Xia; Wang, Xiang; Li, Jia-Jia; Wu, Yan-Bo; Wang, Xiaotai

    2016-01-15

    Density functional theory computations (B3LYP) have been used to explore the chemistry of titanium-aromatic carbon "edge complexes" with 1,3-metal-carbon (1,3-MC) bonding between Ti and planar tetracoordinate Cβ . The titanium-coordinated, end-capping chlorides are replaced with OH or SH groups to afford two series of difunctional monomers that can undergo condensation to form oxide- and sulfide-bridged oligomers. The sulfide-linked oligomers have less molecular strain and are more exergonic than the corresponding oxide-linked oligomers. The HOMO-LUMO gap of the oligomers varies with their composition and decreases with growing oligomer chain. This theoretical study is intended to enrich 1,3-MC bonding and planar tetracoordinate carbon chemistry and provide interesting ideas to experimentalists. Organometallic complexes with the TiE2 (E = OH and SH) decoration on the edge of aromatic hydrocarbons have been computationally designed, which feature 1,3-metal-carbon (1,3-MC) bonding between titanium and planar tetracoordinate β-carbon. Condensation of these difunctional monomers by eliminating small molecules (H2O and H2S) produce chain-like oligomers. The HOMO-LUMO gaps of the oligomers decreases with growing oligomer chain, a trend that suggests possible semiconductor properties for oligomers with longer chains. PMID:26399226

  3. Highly Efficient Oxidative Cleavage of Carbon-Carbon Double Bond over meso-Tetraphenyl Cobalt Porphyrin Catalyst in the Presence of Molecular Oxygen

    Institute of Scientific and Technical Information of China (English)

    周贤太; 纪红兵

    2012-01-01

    Highly efficient and selective carbon-carbon double bond aerobic cleavage of olefins catalyzed by metallopor- phyrins was investigated, and carbonyl compounds and epoxide were produced as the main products. CoTPP (co- balt meso-tetraphenyl porphyrin) showed excellent activity for the oxidative cleavage of carbon-carbon double bond by using styrene as model compound, in which the TOF (turnover frequency) and selectivity toward benzaldehyde was obtained with 2×10^4h-1 and 86%,respectively.

  4. Environmental bonds and the challenge of long-term carbon sequestration.

    Science.gov (United States)

    Gerard, David; Wilson, Elizabeth J

    2009-02-01

    The potential to capture carbon from industrial sources and dispose of it for the long-term, known as carbon capture and sequestration (CCS), is widely recognized as an important option to reduce atmospheric carbon dioxide emissions. Specifically, CCS has the potential to provide emissions cuts sufficient to stabilize greenhouse gas levels, while still allowing for the continued use of fossil fuels. In addition, CCS is both technologically-feasible and commercially viable compared with alternatives with the same emissions profile. Although the concept appears to be solid from a technical perspective, initial public perceptions of the technology are uncertain. Moreover, little attention has been paid to developing an understanding of the social and political institutional infrastructure necessary to implement CCS projects. In this paper we explore a particularly dicey issue--how to ensure adequate long-term monitoring and maintenance of the carbon sequestration sites. Bonding mechanisms have been suggested as a potential mechanism to reduce these problems (where bonding refers to financial instruments used to ensure regulatory or contractual commitments). Such mechanisms have been successfully applied in a number of settings (e.g., to ensure court appearances, completion of construction projects, and payment of taxes). The paper examines the use of bonding to address environmental problems and looks at its possible application to nascent CCS projects. We also present evidence on the use of bonding for other projects involving deep underground injection of materials for the purpose of long-term storage or disposal. PMID:18619728

  5. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    OpenAIRE

    Cantrell, John H.

    2015-01-01

    The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds) formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS) of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites,...

  6. Mechanical Analysis of Stress Distribution in a Carbon Fiber-Reinforced Polymer Rod Bonding Anchor

    Directory of Open Access Journals (Sweden)

    Peng Feng

    2014-04-01

    Full Text Available This paper presents an elastic shear stress distribution theoretical model at the carbon fiber-reinforced polymer (CFRP-adhesive interface of a single-rod and a multi-rod straight-pipe bonding anchor. A comparison between theoretical and finite element analysis results reveals that the accuracy of the theory can be used to guide the preliminary design of CFRP rod bonding anchors. The mechanical performance of the inner cone bonding anchor for multi-rods are evaluated within different coefficients of friction and inner inclined angles. Numerical results indicate that the straight-parabolic inner cone bonding anchor has a significant effect on reducing the shear force at the loading end.

  7. New cleaning strategies based on carbon nanomaterials applied to the deteriorated marble surfaces: A comparative study with enzyme based treatments

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Federica, E-mail: federica.valentini@uniroma2.it [Dipartimento di Scienze e Tecnologie Chimiche, Universita degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Diamanti, Alessia; Carbone, M. [Dipartimento di Scienze e Tecnologie Chimiche, Universita degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Bauer, E.M. [Istituto di Struttura della Materia del Consiglio Nazionale delle Ricerche (ISM-CNR), RM 1, Via Salaria km 29.3, 00015 Monterotondo (Italy); Palleschi, Giuseppe [Dipartimento di Scienze e Tecnologie Chimiche, Universita degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2012-06-01

    Pentelic marbles from Basilica Neptuni in Rome-Italy (27-25 B.C.) show the signs of deterioration phenomena, which can be identified as black crust as well as black and grey patina. The present study has the twofold objective of assessing the entity of the deterioration and proposing new cleaning strategies based on nanotechnologies. The former is achieved by performing optical microscopy, differential interference contrast (DIC), stereomicroscopy, scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and infrared Fourier transform spectroscopy (FT-IR) analysis. The second objective of this study, involves different treatments based on a new cleaning strategy with carbon nanomaterials and bio-cleaning (used here for comparison) performed with enzymes, as glucose oxidase (GOD) and lipase. Nanomicelles assembled with functionalised carbon nano-fibres (CNF-COOH) and dispersed in Tween 20 medium show the highest cleaning performances in terms of removal of the black crust, compared with the pristine single-wall carbon nanotubes (SWCNTs) and the enzyme-based cleaning treatments. In particular, in these last two cases, the GOD-based biocleaning is efficient in removing the grey and dark patina, but works slow on the black crust. Finally, the lipase based cleaning approach is efficient in the black patina removal, though at the working temperature of 38 Degree-Sign C.

  8. Bond strengths of New Carbon-nitride-Related material C2N2(CH2)

    International Nuclear Information System (INIS)

    A new carbon-nitride-related material C2N2(CH2) nanopletelet was synthesized by subjecting a precursor C3N4HxOy+Au in a laser-heating diamond anvil cell (LHDAC) to the pressure of 40 GPa and the temperature of 1200-2000 K. The synthesized C2N2(CH2) was accordingly found to be an orthorhombic unit cell of the space group Cmc21 with lattice constants a = 7.625Å, b = 4.490Å, and c = 4.047Å. The bulk modulus B0 was determined to be B0 = 258 ± 3.4 GPa, only the 60 % that of the diamond. C2N2(CH2) consists of the tetrahedrally coordinated C with three C-N single bond and the one C-C single bond, and the bridging carbon with the C-CH2-C bond. The C-N single bond length of the tetrahedron ranges from 1.444 to 1.503 Å. This bond length is close to the C-N single bond of 1.447 to 1.458 Å in the superhard β-C3N4. The compressibility of the C-N and C-C single bond of C2N2(CH2) ranges from 0.976 to 0.982 with the pressure of 30 GPa. These values are very close to the compressibility of the C-N and C-C single bond of 0.978 to 0.982 in β-C3N4, cubic-C3N4, and diamond.

  9. The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films

    International Nuclear Information System (INIS)

    This work describes the composition and bonding structure of hydrogenated carbon nitride (a-CNx:H) films synthesized by electron cyclotron resonance chemical vapor deposition using as precursor gases argon, methane, and nitrogen. The composition of the films was derived from Rutherford backscattering and elastic recoil detection analysis and the bonding structure was examined by infrared (IR) spectroscopy and x-ray absorption near edge spectroscopy (XANES). By varying the nitrogen to methane ratio in the applied gas mixture, polymeric a-CNx:H films with N/C contents varying from 0.06 to 0.49 were obtained. Remarkably, the H content of the films (∼40 at. %) was rather unaffected by the nitrogenation process. The different bonding states as detected in the measured XANES C(1s) and N(1s) spectra have been correlated with those of a large number of reference samples. The XANES and IR spectroscopy results indicate that N atoms are efficiently incorporated into the amorphous carbon network and can be found in different bonding environments, such as pyridinelike, graphitelike, nitrilelike, and amino groups. The nitrogenation of the films results in the formation of N-H bonding environments at the cost of C-H structures. Also, the insertion of N induces a higher fraction of double bonds in the structure at the expense of the linear polymerlike chains, hence resulting in a more cross-linked solid. The formation of double bonds takes place through complex C=N structures and not by formation of graphitic aromatic rings. Also, the mechanical and tribological properties (hardness, friction, and wear) of the films have been studied as a function of the nitrogen content. Despite the major modifications in the bonding structure with nitrogen uptake, no significant changes in these properties are observed

  10. Cooperativity between Al Sites Promotes Hydrogen Transfer and Carbon-Carbon Bond Formation upon Dimethyl Ether Activation on Alumina.

    Science.gov (United States)

    Comas-Vives, Aleix; Valla, Maxence; Copéret, Christophe; Sautet, Philippe

    2015-09-23

    The methanol-to-olefin (MTO) process allows the conversion of methanol/dimethyl ether into olefins on acidic zeolites via the so-called hydrocarbon pool mechanism. However, the site and mechanism of formation of the first carbon-carbon bond are still a matter of debate. Here, we show that the Lewis acidic Al sites on the 110 facet of γ-Al2O3 can readily activate dimethyl ether to yield CH4, alkenes, and surface formate species according to spectroscopic studies combined with a computational approach. The carbon-carbon forming step as well as the formation of methane and surface formate involves a transient oxonium ion intermediate, generated by a hydrogen transfer between surface methoxy species and coordinated methanol on adjacent Al sites. These results indicate that extra framework Al centers in acidic zeolites, which are associated with alumina, can play a key role in the formation of the first carbon-carbon bond, the initiation step of the industrial MTO process. PMID:27162986

  11. Adsorption of glycine on diamond (001): Role of bond angle of carbon atoms

    Science.gov (United States)

    Li, Lin; Xu, Jing; Xu, Li-Fang; Lian, Chao-Sheng; Li, Jun-Jie; Wang, Jian-Tao; Gu, Chang-Zhi

    2015-05-01

    The adsorption behaviors of glycine on diamond (001) are systematically investigated by first-principles calculations. We have considered all possible adsorption configurations without a surface dangling bond and give a quantitative analysis for the relationship between the deviation of carbon bond angle and adsorption energy. We found that a smaller distortion of carbon covalent bond angle results in a more stable adsorption structure, and the most stable adsorption has a benzene-ring-like structure with the highest adsorption energy of 5.11 eV per molecule and the minimum distortion of carbon covalent bond angle. Project supported by the National Natural Science Foundation of China (Grant Nos. 51272278, 91323304, 10774177, and 11374341), the National Basic Research Program of China (Grand No. 2009CB930502), the Knowledge Innovation Project of Chinese Academy of Sciences (Grand No. KJCX2-EW-W02), the Fundamental Research Funds for the Central Universities of Ministry of Education of China, and the Research Funds of Renmin University of China.

  12. Migration behaviour of carbon atoms on clean diamond (0 0 1) surface: A first principle study

    Science.gov (United States)

    Liu, Xuejie; Xia, Qing; Li, Wenjuan; Luo, Hao; Ren, Yuan; Tan, Xin; Sun, Shiyang

    2016-01-01

    The adsorption and migration energies of a single carbon atom and the configuration evolution energies of two carbon atoms on a clean diamond (0 0 1) surface were calculated using the first principle method based on density functional theory to investigate the formation of ultra-nanocrystalline diamond (UNCD) film. The activation energy of a single atom diffusing along a dimer row is 1.96 eV, which is almost the same as that of a CH2 migrating along a dimer row under hydrogen-rich conditions. However, the activation energy of a single atom diffusing along a dimer chain is 2.66 eV, which is approximately 1.55 times greater than that of a CH2 migrating along a dimer chain in a hydrogen-rich environment. The configuration evolution of the two carbon atoms is almost impossible at common diamond film deposition temperatures (700-900 °C) because the activation energies reach 4.46 or 5.90 eV. Therefore, the high-energy barrier could result in insufficient migration of adatoms, leading to the formation of amorphous in UNCD films in hydrogen-poor CVD environment.

  13. Socioeconomic Factors Affecting Farmers’ Awareness of Clean Development Mechanism Projects: Case of Smallholder Forest Carbon Projects

    Directory of Open Access Journals (Sweden)

    Oscar I. Ayuya

    2011-05-01

    Full Text Available The objective of the study was to identify the socio-economic and institutional factors which influence the level of awareness of Clean Development Mechanism (CDM projects and in so doing to highlight the policy implications for the stakeholders when designing clean development mechanism projects among smallholder farmers. Findings shows that 23% of the farmers were correctly aware of the project and the results of the ordered logit model indicate that age, gender, education level, group membership, existence of tree farming and contact with extension services was found to influence awareness level of smallholder forest Carbon projects. To assist the community to adapt to climate change and produce sufficiently on a sustainable basis and achieve the desired food security under climate change challenges, the study recommends policies to increase awareness of such agro-environmental initiatives and that of extension providers should distinguish their clientele anchored on vital demographic characteristics such as age and gender. If the probability of younger farmers to be aware this initiative is higher, extension communications should be directed to such age group, particularly during initial stages project information dissemination.

  14. Going Clean - The Economics of China's Low-carbon Development

    Energy Technology Data Exchange (ETDEWEB)

    Hallding, Karl; Thai, Helen; Han, Guoyi; Olsson, Marie; Kartha, Sivan (Stockholm Environment Inst. (Sweden)); Eklund, Klas (SEB, Stockholm (Sweden)); SU Ming (Peking Univ. (China)); Cao Jing (Tsinghua Univ. (China)); Luderer (Potsdam Inst. for Climate Impact (Germany))

    2009-11-15

    -scale abatement. Carbon pricing mechanisms can also assist clean technology objectives, as anticipation of higher carbon prices sets an incentive to develop low-carbon technology and products, and can thus steer investments in this direction. In addition, we propose a new international finance mechanism - the Inter-country Joint Mitigation Plan - as a broader and more efficient way of financing technology transfers. There needs to be a substantial, stable and predictable source of international finance, accompanied by market reform and regulatory mechanisms that can recognise, support and deepen domestic mitigation and adaptation efforts. International assistance will fuel and accelerate China's shift to a knowledge-based economy. China faces a monumental challenge and a historic opportunity. The transition to a low-carbon society will require large investments but also bring about substantial benefits, not only to China but to the entire world

  15. The convenient truth LPG: clean energy for a low carbon world

    International Nuclear Information System (INIS)

    In the context of climate change, no one solution is future-proof. It is going to take a coordinated worldwide effort to find the right mix of energy policies while balancing diverse and sometimes competing priorities. The WLPGA Climate Change Working Group (CCWG) seeks to demonstrate that the technologies needed to continue current rates of development while mitigating climate change already exist and that LP gas can be a major part of today's solutions to this challenge. LP gas is not a zero-GHG fuel. However, in most cases it can make major and immediate contributions to delivering real GHG emissions reductions. In some ways LP Gas can claim to be ahead of its time, for its clean-burning, low-carbon advantage is available at once, so that even using today's technology, most industries can exceed Kyoto GHG reduction targets by switching to LP Gas. The fact is that LP Gas produces lower GHG emissions compared to conventional energy supplies in virtually every application it is used, from stationary applications such as water heating, space heating, cooking and industrial boilers to transportation applications. There are opportunities to switch to clean burning LP gas for virtually every industry as a means meet GHG targets. LP gas is also portable, making it a perfect complement to distributed renewable energy source such as solar, wind and wave energy (and soon the fuel cell), thereby reducing our reliance centrally produced electricity. LP Gas used in combination with these renewable sources also can improve energy reliability while reducing the overall life-cycle costs. The portable and clean burning nature of LP Gas also makes it an ideal substitute for solid fuels in domestic cooking and heating applications. Household solid fuel use, overwhelmingly concentrated in developing countries, accounts for up to 30% of black carbon emissions worldwide according to some statistics. Switching to LP Gas could lower global GHG emissions as well as help to diminish

  16. Investigation of the Interactions and Bonding between Carbon and Group VIII Metals at the Atomic Scale.

    Science.gov (United States)

    Zoberbier, Thilo; Chamberlain, Thomas W; Biskupek, Johannes; Suyetin, Mikhail; Majouga, Alexander G; Besley, Elena; Kaiser, Ute; Khlobystov, Andrei N

    2016-03-23

    The nature and dynamics of bonding between Fe, Ru, Os, and single-walled carbon nanotubes (SWNTs) is studied by aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM). The metals catalyze a wide variety of different transformations ranging from ejection of carbon atoms from the nanotube sidewall to the formation of hollow carbon shells or metal carbide within the SWNT, depending on the nature of the metal. The electron beam of AC-HRTEM serves the dual purpose of providing energy to the specimen and simultaneously enabling imaging of chemical transformations. Careful control of the electron beam parameters, energy, flux, and dose allowed direct comparison between the metals, demonstrating that their chemical reactions with SWNTs are determined by a balance between the cohesive energy of the metal particles and the strength of the metal-carbon σ- or π-bonds. The pathways of transformations of a given metal can be drastically changed by applying different electron energies (80, 40, or 20 keV), thus demonstrating AC-HRTEM as a new tool to direct and study chemical reactions. The understanding of interactions and bonding between SWNT and metals revealed by AC-HRTEM at the atomic level has important implications for nanotube-based electronic devices and catalysis. PMID:26848826

  17. Correlation between carbon-carbon bond length and the ease of retro Diels-Alder reaction

    Indian Academy of Sciences (India)

    Sambasivarao Kotha; Shaibal Banerjee; Mobin Shaikh

    2014-09-01

    The bond length between C8-C9 in (1′R,4′S,4a′R,8a′S)-6′,7′-dimethyl-1′,4′,4a′,8a′-tetrahydrospiro [cyclopropane-1,9′-[1,4]methanonaphthalene]-5′,8′-dione is 1.571 (2) Å and between C7-C12 is 1.567 (2) Å which are longer than the corresponding bond length for saturated bicyclic systems (1.531-1.535Å). This paper reports the correlation between bond length and the ease of retro Diels−Alder reaction.

  18. Effects of welding fumes on nuclear air cleaning system carbon adsorber banks

    International Nuclear Information System (INIS)

    Standard Technical Specifications for nuclear air cleaning systems include requirements for surveillance tests following fire, painting, or chemical release in areas communicating with the affected system. To conservatively implement this requirement, many plants categorize welding as a chemical release process, and institute controls to ensure that welding fumes do not interact with carbon adsorbers in a filter system. After reviewing research data that indicated welding had a minimal impact on adsorber iodine removal efficiency, further testing was performed with the goal of establishing a welding threshold. It was anticipated that some quantity of weld electrodes could be determined that had a corresponding detrimental impact on iodine removal efficiency for the exposed adsorber. This value could be used to determine a conservative sampling schedule that would allow the station to perform laboratory testing to ensure system degradation did not occur without a full battery of surveillance tests. A series of tests was designed to demonstrate carbon efficiency versus cumulative welding fume exposure. Three series of tests were performed, one for each of three different types of commonly used weld electrodes. Carbon sampling was performed at baseline conditions, and every five pounds of electrode thereafter. Two different laboratory tests were performed for each sample; one in accordance with ASTM 3803/1989 at 95% relative humidity and 30 degrees C, and another using the less rigorous conditions of 70% relative humidity and 80 degrees C. Review of the test data for all three types of electrodes failed to show a significant correlation between carbon efficiency degradation and welding fume exposure. Accordingly, welding is no longer categorized as a 'chemical release process' at McGuire Nuclear Station, and limits on welding fume interaction with ventilation systems have been eliminated. 4 refs., 3 figs., 1 tab

  19. Effects of welding fumes on nuclear air cleaning system carbon adsorber banks

    Energy Technology Data Exchange (ETDEWEB)

    Roberson, P.W. [Duke Power Company, Huntersville, NC (United States)

    1997-08-01

    Standard Technical Specifications for nuclear air cleaning systems include requirements for surveillance tests following fire, painting, or chemical release in areas communicating with the affected system. To conservatively implement this requirement, many plants categorize welding as a chemical release process, and institute controls to ensure that welding fumes do not interact with carbon adsorbers in a filter system. After reviewing research data that indicated welding had a minimal impact on adsorber iodine removal efficiency, further testing was performed with the goal of establishing a welding threshold. It was anticipated that some quantity of weld electrodes could be determined that had a corresponding detrimental impact on iodine removal efficiency for the exposed adsorber. This value could be used to determine a conservative sampling schedule that would allow the station to perform laboratory testing to ensure system degradation did not occur without a full battery of surveillance tests. A series of tests was designed to demonstrate carbon efficiency versus cumulative welding fume exposure. Three series of tests were performed, one for each of three different types of commonly used weld electrodes. Carbon sampling was performed at baseline conditions, and every five pounds of electrode thereafter. Two different laboratory tests were performed for each sample; one in accordance with ASTM 3803/1989 at 95% relative humidity and 30 degrees C, and another using the less rigorous conditions of 70% relative humidity and 80 degrees C. Review of the test data for all three types of electrodes failed to show a significant correlation between carbon efficiency degradation and welding fume exposure. Accordingly, welding is no longer categorized as a `chemical release process` at McGuire Nuclear Station, and limits on welding fume interaction with ventilation systems have been eliminated. 4 refs., 3 figs., 1 tab.

  20. Comparison of H2 and He carbon cleaning mechanisms in extreme ultraviolet induced and surface wave discharge plasmas

    CERN Document Server

    Dolgov, A; Rachimova, T; Kovalev, A; Vasilyeva, A; Lee, C J; Krivtsun, V M; Yakushev, O; Bijkerk, F

    2013-01-01

    Cleaning of contamination of optical surfaces by amorphous carbon (a-C) is highly relevant for extreme ultraviolet (EUV) lithography. We have studied the mechanisms for a-C removal from a Si surface. By comparing a-C removal in a surface wave discharge (SWD) plasma and an EUV-induced plasma, the cleaning mechanisms for hydrogen and helium gas environments were determined. The C-atom removal per incident ion was estimated for different sample bias voltages and ion fluxes. It was found that H2 plasmas generally had higher cleaning rates than He plasmas: up to seven times higher for more negatively biased samples in EUV induced plasma. Moreover, for H2, EUV induced plasma was found to be 2-3 times more efficient at removing carbon than the SWD plasma. It was observed carbon removal during exposure to He is due to physical sputtering by He+ ions. In H2, on the other hand, the increase in carbon removal rates is due to chemical sputtering. This is a new C cleaning mechanism for EUV-induced plasma, which we call "E...

  1. Intermediate sp-hybridization for chemical bonds in nonplanar covalent molecules of carbon

    International Nuclear Information System (INIS)

    General representations for symmetrical and asymmetrical intermediate sp-hybridization are provided, with which the development of electronic structure in C3v-symmetrical C2H6 and the bonding configuration in C60 have been analyzed as an example. The spherical structure of C60 does not necessarily require the fourth hybrid, h4, to lie along the radial direction. Rather, h4 runs at an angle of 3.83° from the radius, in the plane bisecting a pentagon, to achieve maximum overlap with adjacent h4-hybrids. By virtue of these representations, a number of properties of covalent molecules and solids can be conveniently calculated. This work might be particularly helpful for the study of C—C bonding in curved structures of carbon, such as fullerenes, carbon nanotubes, and buckled graphene

  2. Carbon fiber/reaction-bonded carbide matrix for composite materials - Manufacture and characterization

    International Nuclear Information System (INIS)

    The processing of self-healing ceramic matrix composites by a short time and low cost process was studied. This process is based on the deposition of fiber dual inter-phases by chemical vapor infiltration and on the densification of the matrix by reactive melt infiltration of silicon. To prevent fibers (ex-PAN carbon fibers) from oxidation in service, a self-healing matrix made of reaction bonded silicon carbide and reaction bonded boron carbide was used. Boron carbide is introduced inside the fiber preform from ceramic suspension whereas silicon carbide is formed by the reaction of liquid silicon with a porous carbon xerogel in the preform. The ceramic matrix composites obtained are near net shape, have a bending stress at failure at room temperature around 300 MPa and have shown their ability to self-healing in oxidizing conditions. (authors)

  3. Fabrication and characterization of reaction bonded silicon carbide/carbon nanotube composites

    International Nuclear Information System (INIS)

    Carbon nanotubes have generated considerable excitement in the scientific and engineering communities because of their exceptional mechanical and physical properties observed at the nanoscale. Carbon nanotubes possess exceptionally high stiffness and strength combined with high electrical and thermal conductivities. These novel material properties have stimulated considerable research in the development of nanotube-reinforced composites (Thostenson et al 2001 Compos. Sci. Technol. 61 1899, Thostenson et al 2005 Compos. Sci. Technol. 65 491). In this research, novel reaction bonded silicon carbide nanocomposites were fabricated using melt infiltration of silicon. A series of multi-walled carbon nanotube-reinforced ceramic matrix composites (NT-CMCs) were fabricated and the structure and properties were characterized. Here we show that carbon nanotubes are present in the as-fabricated NT-CMCs after reaction bonding at temperatures above 1400 deg. C. Characterization results reveal that a very small volume content of carbon nanotubes, as low as 0.3 volume %, results in a 75% reduction in electrical resistivity of the ceramic composites. A 96% decrease in electrical resistivity was observed for the ceramics with the highest nanotube volume fraction of 2.1%

  4. Development of a rubber toughened epoxy adhesive loaded with carbon nanotubes, for aluminium – polymer bonds

    OpenAIRE

    Salinas-Ruiz , Maria del Mar

    2009-01-01

    This thesis describes the formulation of a ternary thermosetting adhesive which consists of a diglycidyl ether of bisphenol-A (DGEBA) epoxy resin cured with 3,3’-diamino diphenyl sulphone (3,3’-DDS) hardener and modified through the addition of carboxyl- terminated butadiene-acrylonitrile (CTBN) rubber and multi-walled carbon nanotubes (MWCNTs). Processing implications of the novel adhesive in the film form are considered in order to manufacture bonded specimens for characteris...

  5. Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

    Directory of Open Access Journals (Sweden)

    Tsuyuka Sugiishi

    2015-12-01

    Full Text Available This short review highlights the copper-mediated fluoroalkylation using perfluoroalkylated carboxylic acid derivatives. Carbon–carbon bond cleavage of perfluoroalkylated carboxylic acid derivatives takes place in fluoroalkylation reactions at high temperature (150–200 °C or under basic conditions to generate fluoroalkyl anion sources for the formation of fluoroalkylcopper species. The fluoroalkylation reactions, which proceed through decarboxylation or tetrahedral intermediates, are useful protocols for the synthesis of fluoroalkylated aromatics.

  6. Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

    Science.gov (United States)

    Sugiishi, Tsuyuka; Aikawa, Kohsuke

    2015-01-01

    Summary This short review highlights the copper-mediated fluoroalkylation using perfluoroalkylated carboxylic acid derivatives. Carbon–carbon bond cleavage of perfluoroalkylated carboxylic acid derivatives takes place in fluoroalkylation reactions at high temperature (150–200 °C) or under basic conditions to generate fluoroalkyl anion sources for the formation of fluoroalkylcopper species. The fluoroalkylation reactions, which proceed through decarboxylation or tetrahedral intermediates, are useful protocols for the synthesis of fluoroalkylated aromatics. PMID:26734112

  7. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

    OpenAIRE

    G. Sarwar; Godowitch, J.; B. H. Henderson; K. Fahey; Pouliot, G.; W. T. Hutzell; Mathur, R.; Kang, D.; W. S. Goliff; Stockwell, W. R.

    2013-01-01

    We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide...

  8. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

    OpenAIRE

    Sarwar, G.; J. Godowitch; B. H. Henderson; K. Fahey; Pouliot, G.; W. T. Hutzell; Mathur, R.; Kang, D.; Goliff, W. S.; Stockwell, W. R.

    2013-01-01

    We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, peroxyace...

  9. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

    OpenAIRE

    Sarwar, G.; J. Godowitch; Henderson, B.; K. Fahey; Pouliot, G.; W. T. Hutzell; Mathur, R.; Kang, D.; Goliff, W. S.; Stockwell, W. R.

    2013-01-01

    We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, pe...

  10. Reinforced concrete beams strengthened with carbon fiber reinforced polymer by friction hybrid bond technique: Experimental investigation

    International Nuclear Information System (INIS)

    Highlights: • Friction Hybrid Bonded FRP Technique is conducted to strengthen RC beams. • Six specimens with different reinforced methods were tested. • The strengthened effects of different strengthening methods were discussed. • The results obtained from the FEA and experiments are agreed very well. - Abstract: Carbon fiber reinforced polymer (CFRP) can be used to strengthen the reinforced concrete (RC) beams. But premature debonding is the main failure model in ordinary bond technique, and the strengthening effect is limited. In order to improve bonding and restricting sliding displacement, Friction Hybrid Bonded FRP Technique (FHB-FRP) is developed. Six simple-span RC specimen beams with different strengthened methods were tested in four-point bending. The experiment results indicate that FRP debonding can be effectively prevented by the FHB-FRP strengthened beam. The ultimate load-carrying capacity of the specimen strengthened by FHB-FRP technique is able to increase by a factor of 2.13 times compared with the beam strengthened with ordinary bond technique (U-jacketing technique). In addition, the cracking and yielding loads are improved more significantly by FHB-FRP technique than U-jacketing technique. Specimens strengthened with FHB-FRP technique have cracks with a more limited distribution and width. Finally, the finite element method (FEM) is conducted to simulate the behavior of the test specimens. The results obtained from the finite element method are compared with experiment. Excellent agreements have been achieved in the comparison of results

  11. Textile Dry Cleaning Using Carbon Dioxide: Process, Apparatus and Mechanical Action

    OpenAIRE

    Sutanto, S.

    2014-01-01

    Fabrics that are sensitive to water, may wrinkle or shrink when washed in regular washing machines and are usually cleaned by professional dry cleaners. Dry cleaning is a process of removing soils from substrate, in this case textile, using a non-aqueous solvent. The most common solvent in conventional dry cleaning is perchloroethylene (PER). Despite its satisfactory cleaning performance, PER has several drawbacks. One approach is to develop an alternative solvent for PER. CO2 is chosen in th...

  12. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FMI currently manufactures Phenolic Impregnated Carbon Ablator (PICA) material for Thermal Protection Systems (TPS) systems, such as the Stardust Sample Return...

  13. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FMI has developed graded density CBCF preforms for graded density phenolic impregnated carbon ablator (PICA) material to meet NASA's future exploration mission...

  14. High-performance supercapacitor electrode from cellulose-derived, inter-bonded carbon nanofibers

    Science.gov (United States)

    Cai, Jie; Niu, Haitao; Wang, Hongxia; Shao, Hao; Fang, Jian; He, Jingren; Xiong, Hanguo; Ma, Chengjie; Lin, Tong

    2016-08-01

    Carbon nanofibers with inter-bonded fibrous structure show high supercapacitor performance when being used as electrode materials. Their preparation is highly desirable from cellulose through a pyrolysis technique, because cellulose is an abundant, low cost natural material and its carbonization does not emit toxic substance. However, interconnected carbon nanofibers prepared from electrospun cellulose nanofibers and their capacitive behaviors have not been reported in the research literature. Here we report a facile one-step strategy to prepare inter-bonded carbon nanofibers from partially hydrolyzed cellulose acetate nanofibers, for making high-performance supercapacitors as electrode materials. The inter-fiber connection shows considerable improvement in electrode electrochemical performances. The supercapacitor electrode has a specific capacitance of ∼241.4 F g-1 at 1 A g-1 current density. It maintains high cycling stability (negligible 0.1% capacitance reduction after 10,000 cycles) with a maximum power density of ∼84.1 kW kg-1. They may find applications in the development of efficient supercapacitor electrodes for energy storage applications.

  15. Chemical bonding modifications of tetrahedral amorphous carbon and nitrogenated tetrahedral amorphous carbon films induced by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    McCann, R. [NIBEC, School of Electrical and Mechanical Engineering, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, BT37 OQB, N. Ireland (United Kingdom); Roy, S.S. [NIBEC, School of Electrical and Mechanical Engineering, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, BT37 OQB, N. Ireland (United Kingdom)]. E-mail: s.sinha-roy@ulster.ac.uk; Papakonstantinou, P. [NIBEC, School of Electrical and Mechanical Engineering, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, BT37 OQB, N. Ireland (United Kingdom); Bain, M.F. [Queens University of Belfast, School of Elect and Elect Engineering, Belfast, Antrim, N. Ireland (United Kingdom); Gamble, H.S. [Queens University of Belfast, School of Elect and Elect Engineering, Belfast, Antrim, N. Ireland (United Kingdom); McLaughlin, J.A. [NIBEC, School of Electrical and Mechanical Engineering, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, BT37 OQB, N. Ireland (United Kingdom)

    2005-06-22

    Tetrahedral amorphous carbon (ta-C) and nitrogenated tetrahedral amorphous carbon films (ta-CN {sub x}), deposited by double bend off plane Filtered Vacuum Cathodic Arc were annealed up to 1000 deg. C in flowing argon for 2 min. Modifications on the chemical bonding structure of the rapidly annealed films, as a function of temperature, were investigated by NEXAFS, X-ray photoelectron and Raman spectroscopies. The interpretation of these spectra is discussed. The results demonstrate that the structure of undoped ta-C films prepared at floating potential with an arc current of 80 A remains stable up to 900 deg. C, whereas that of ta-CN {sub x} containing 12 at.% nitrogen is stable up to 700 deg. C. At higher temperatures, all the spectra indicated the predominant formation of graphitic carbon. Through NEXAFS studies, we clearly observed three {pi}* resonance peaks at the {sup '}N K edge structure. The origin of these three peaks is not well established in the literature. However our temperature-dependant study ascertained that the first peak originates from C=N bonds and the third peak originates from the incorporation of nitrogen into the graphite like domains.

  16. Financing Public Sector Projects with Clean Renewable Energy Bonds; Fact Sheet Series on Financing Renewable Energy Projects, National Renewable Energy Laboratory (NREL)

    Energy Technology Data Exchange (ETDEWEB)

    Kreycik, C.; Couglin, J.

    2009-12-01

    Clean renewable energy bonds (CREBs) present a low-cost opportunity for public entities to issue bonds to finance renewable energy projects. The federal government lowers the cost of debt by providing a tax credit to the bondholder in lieu of interest payments from the issuer. Because CREBs are theoretically interest free, they may be more attractive than traditional tax-exempt municipal bonds. In February 2009, Congress appropriated a total of $2.4 billion for the "New CREBs" program. No more than one-third of the budget may be allocated to each of the eligible entities: governmental bodies, electric cooperatives, and public power providers. Applications for this round of "New CREBs" were due to the Internal Revenue Service (IRS) on August 4, 2009. There is no indication Congress will extend the CREBs program; thus going forward, only projects that are approved under the 2009 round will be able to issue CREBs. This factsheet explains the CREBs mechanism and provides guidance on procedures related to issuing CREBs.

  17. Method for producing bio-fuel that integrates heat from carbon-carbon bond-forming reactions to drive biomass gasification reactions

    Science.gov (United States)

    Cortright, Randy D.; Dumesic, James A.

    2011-01-18

    A low-temperature catalytic process for converting biomass (preferably glycerol recovered from the fabrication of bio-diesel) to synthesis gas (i.e., H.sub.2/CO gas mixture) in an endothermic gasification reaction is described. The synthesis gas is used in exothermic carbon-carbon bond-forming reactions, such as Fischer-Tropsch, methanol, or dimethylether syntheses. The heat from the exothermic carbon-carbon bond-forming reaction is integrated with the endothermic gasification reaction, thus providing an energy-efficient route for producing fuels and chemicals from renewable biomass resources.

  18. Final Report: Wireless Instrument for Automated Measurement of Clean Cookstove Usage and Black Carbon Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Lukac, Martin [Cirrus Sense LLC, Los Angeles, CA (United States); Ramanathan, Nithya [Cirrus Sense LLC, Los Angeles, CA (United States); Graham, Eric [Cirrus Sense LLC, Los Angeles, CA (United States)

    2013-09-10

    Black carbon (BC) emissions from traditional cooking fires and other sources are significant anthropogenic drivers of radiative forcing. Clean cookstoves present a more energy-efficient and cleaner-burning vehicle for cooking than traditional wood-burning stoves, yet many existing cookstoves reduce emissions by only modest amounts. Further research into cookstove use, fuel types, and verification of emissions is needed as adoption rates for such stoves remain low. Accelerated innovation requires techniques for measuring and verifying such cookstove performance. The overarching goal of the proposed program was to develop a low-cost, wireless instrument to provide a high-resolution profile of the cookstove BC emissions and usage in the field. We proposed transferring the complexity of analysis away from the sampling hardware at the measurement site and to software at a centrally located server to easily analyze data from thousands of sampling instruments. We were able to build a low-cost field-based instrument that produces repeatable, low-cost estimates of cookstove usage, fuel estimates, and emission values with low variability. Emission values from our instrument were consistent with published ranges of emissions for similar stove and fuel types.

  19. Hydrogen bonding inside and outside carbon nanotubes: HF dimer as a case study.

    Science.gov (United States)

    Roztoczyńska, Agnieszka; Kozłowska, Justyna; Lipkowski, Paweł; Bartkowiak, Wojciech

    2016-01-28

    In this theoretical work we analyze the noncovalent interactions of molecular complexes formed between the hydrogen bonded HF dimer and single-walled carbon nanotubes (SWCNTs) of different diameters. In particular, the interaction energies of: (i) spatially confined hydrogen fluoride molecules and (ii) HF dimer and the exterior or interior of SWCNTs are investigated. The computations are carried out in a supermolecular manner using the M06-2X exchange-correlation functional. In order to establish the influence of mutual orientation of the hydrogen fluoride dimer and molecular carbon cages on the analyzed energetic parameters energy scans are performed. Furthermore, changes in the charge distribution of the investigated endo- and exohedral complexes are studied employing the Natural Bond Orbital analysis. Among others, the position of the HF dimer with respect to the carbon cages proves to have a significant influence on the analyzed quantities. The results of our study also indicate that the HF dimer interacts stronger with the interior rather than the exterior of SWCNTs. Moreover, a substantial enhancement of the basis set superposition error is disclosed. PMID:26701220

  20. A LASER INTERFERENCE-BASED SURFACE TREATMENT OF AL AND CARBON FIBER POLYMER COMPOSITES FOR ENHANCED BONDING

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Warren, Charles David [ORNL; ERDMAN III, DONALD L [ORNL; Daniel, Claus [ORNL; Skszek, Timothy [Vehma International of American, Inc.; Caruso-Dailey, Mary M. [3M Company

    2016-01-01

    Due to its increased use in the automotive and aerospace industries, joining of Carbon Fiber-reinforced Polymer matrix Composites (CFPC) to metals demands enhanced surface preparation and control of surface morphology prior to joining. In this study, surfaces of both composite and aluminum were prepared for joining using a new laser based technique, in which the laser interference power profile was created by splitting the beam and guiding those beams to the sample surface by overlapping each other with defined angles to each other. Results were presented for the overlap shear testing of single-lap joints made with Al 5182 and CFPC specimens whose surfaces prepared by (a) surface abrasion and solvent cleaning; and (b) laser-interference structured surfaces by rastering with a 4 mm laser beam at approximately 3.5 W power. CFPC specimens of T700S carbon fiber, Prepreg T70 epoxy, 4 or 5 ply thick, 0/90o plaques were used. Adhesive DP810 was used to bond Al and CFPC. The bondline was 0.25mm and the bond length was consistent among all joints produced. First, the effect of the laser speed on the joint performance was evaluated by laser-interference structure Al and CFPC surfaces with a beam angle of 3o and laser beam speeds of 3, 5, and 10 mm/s. For this sensitivity study, 3 joint specimens were used per each joint type. Based on the results for minimum, maximum, and mean values for the shear lap strength and maximum load for all the 9 joint types, two joint types were selected for further evaluations. Six additional joint specimens were prepared for these two joint types in order to obtain better statistics and the shear test data was presented for the range, mean, and standard deviation. The results for the single-lap shear tests obtained for six joint specimens, indicate that the shear lap strength, maximum load, and displacement at maximum load for those joints made with laser-interference structured surfaces were increased by approximately 14.8%, 16%, and 100

  1. Normal, high and ultra-high modulus carbon fiber-reinforced polymer laminates for bonded and un-bonded strengthening of steel beams

    International Nuclear Information System (INIS)

    Highlights: • Normal, high and ultra-high modulus CFRP laminates for strengthening of steel beams. • Bonded and un-bonded reinforcement systems for steel beams. • Comparisons between the static behavior of the bonded and un-bonded systems. - Abstract: This paper studies the elastic behavior of steel beams strengthened with normal, high and ultra-high modulus CFRP laminates using bonded and un-bonded systems. The elastic behavior of retrofitted beams provides useful information for design of fatigue strengthening systems. A total of seven steel beams including one control unstrengthened beam and six strengthened beams were tested statically until failure in a simply supported four-point bending set-up. The steel beams were retrofitted by normal modulus (NM), high modulus (HM) and ultra-high modulus (UHM) carbon fiber-reinforced polymer (CFRP) laminates with nominal Young’s moduli, ranging from 165 to 440 GPa. Each type of laminate was attached to the steel beams using bonded reinforcement (BR) and un-bonded reinforcement (UR) systems. There is no direct comparison between the BR and the UR systems in the literature. The main goal of the paper is to provide a better understating about the stress distribution along the beam bottom flange when the BR and the UR systems are used for strengthening. All specimens failed due to lateral-torsional buckling (LTB). The effect of different strengthening methods on buckling capacity of the retrofitted specimens was also studied. Experimental results have shown that strengthening using bonded UHM laminates could increase the stiffness of the composite section so that the steel profile has yielded prior to buckling and a larger reinforcement efficacy was then achieved

  2. Chemical bonding in hard and elastic amorphous carbon-nitride films

    Science.gov (United States)

    Gammon, Wesley Jason

    In this study, the chemical bonding in hard and elastic amorphous carbon nitride (a-CNx) films is investigated with x-ray photoelectron spectroscopy (XPS) and 15N, 13C, and 1H nuclear magnetic resonance (NMR) spectroscopy. The films were deposited by DC Magnetron sputtering in a pure nitrogen discharge on Si(001) substrates at 300--400°C. Nanoindentation measurements reveal an elastic modulus of ˜50 GPa and a hardness of ˜5 GPa, thus confirming our films are highly elastic but resist plastic deformation. Our 13C NMR study demonstrates the absence of sp 3-bonded carbon in this material. Collectively, our N(1s) XPS, 13C NMR, and 15N NMR data suggest a film-bonding model that has an aromatic carbon structure with sp2-hybridized nitrogen incorporated in heterocyclic rings. We demonstrate that the nitrogen bonding is predominantly in configurations similar to those in pyridine and pyrrole. In addition, the data indicate that the a-CNx films prepared for this study have low hydrogen content, but are hydrophilic. Specifically, results from 15N and 13C cross polarization (CP) and 1H magic angle spinning (MAS) NMR experiments suggest that nitrogen sites are susceptible to protonation from water absorbed during sample preparation for the NMR experiments. The sensitivity of the surface of a-CNx to water absorption may impact tribological applications for this material. In accord with our XPS and NMR spectroscopic studies on a-CN x films, we propose a film-structure model consisting of buckled graphitic planes that are cross-linked together by sp2 hybridized carbons. The curvature and cross-linking is attributed to a type of compound defect, which is formed by placing a pentagon next to single-atom vacancy in a graphite layer. Our proposed film structure is called the pentagon-with-vacancy-defect (5VD) model. Using Hartree-Fock calculations, we show that the 5VD, film-structure model is compatible with our XPS, NMR, and nanoindentation measurements and with previous

  3. tert-Butanesulfinamides as Nitrogen Nucleophiles in Carbon-Nitrogen Bond Forming Reactions.

    Science.gov (United States)

    Ramirez Hernandez, Johana; Chemla, Fabrice; Ferreira, Franck; Jackowski, Olivier; Oble, Julie; Perez-Luna, Alejandro; Poli, Giovanni

    2016-01-01

    The use of tert-butanesulfinamides as nitrogen nucleophiles in carbon-nitrogen bond forming reactions is reviewed. This field has grown in the shadow of the general interest in N-tert-butanesulfinyl imines for asymmetric synthesis and occupies now an important place in its own right in the chemistry of the chiral amine reagent tert-butanesulfinamide. This article provides an overview of the area and emphasizes recent contributions wherein the tert-butanesulfinamides act as chiral auxiliaries or perform as nitrogen donors in metal-catalyzed amination reactions. PMID:26931222

  4. Effects of cleaning agents on bond strength to dentin Efeitos de agentes de limpeza na resistência adesiva à dentina

    Directory of Open Access Journals (Sweden)

    Celso Rosin

    2005-06-01

    Full Text Available The cleaning of cavity walls aims to improve adhesive restorative procedures and longevity of restorations. This study has compared the effect of three cleaning agents - sodium bicarbonate jet (Profi II, Dabi Atlante, São Paulo, Brazil; pumice paste plus a biologic detergent (Tergestesim, Probem, São Paulo, Brazil; air water spray - on the bond strength between dentin and two different adhesive systems: Clearfil SE Bond (Kuraray, Kioto, Japan and Scotchbond Multi-Purpose Plus (3M-ESPE, São Paulo, Brazil. Six groups (n:10 of dental fragments obtained from young adult extracted teeth were prepared, and each one received one of the listed surface cleaning techniques. After the adhesive application, a cone-shaped test body was built with AP-X (Kuraray, Kioto, Japan or Z100 (3M-ESPE, São Paulo, Brazil composite resins, using a Teflon matrix. The specimens were tested for tensile bond strength after one-week storage in distilled water at 37°C. Two pairs of fractured specimens of each group were randomly chosen and processed for scanning electron microscopy (SEM analysis. ANOVA test of the bond strength values showed no statistical differences among the cleaning agents and neither between their interactions with the bonding systems. Upon SEM analysis, most surfaces showed mixed fractures of adhesive and cohesive failures in bonding resin to dentin. Based on statistical and SEM analysis, it was concluded that the cleaning agents studied did not interfere with the bond strength of the adhesive systems used to dentin.A limpeza das paredes cavitárias é um passo importante na clínica odontológica e visa otimizar os procedimentos adesivos e a longevidade das restaurações. O presente estudo comparou o efeito de três agentes de limpeza cavitária - jato abrasivo de bicarbonato de sódio/ar/água (Profi II, Dabi Atlante, São Paulo, Brasil; pasta de pedra-pomes e água, somada a um detergente biológico (Tergestesim, Probem, São Paulo, Brasil; e

  5. A Contribution of Foreign Direct Investment, Clean Energy, Trade Openness, Carbon Emissions and Economic Growth to Energy Demand in UAE

    OpenAIRE

    SBIA, Rashid; Shahbaz, Muhammad; Hamdi, Helmi

    2013-01-01

    This paper investigates the relationship between foreign direct investment, clean energy, trade openness, carbon emissions and economic growth in case of UAE covering the period of 1975Q1-2011Q4. We have tested the unit properties of variables in the presence of structural breaks. The ARDL bounds testing approach is applied to examine the cointegration by accommodating structural breaks stemming in the series. The VECM Granger causality approach is also applied to investigate the causal relat...

  6. Effects of carbon fiber surface characteristics on interfacial bonding of epoxy resin composite subjected to hygrothermal treatments

    International Nuclear Information System (INIS)

    The changes of interfacial bonding of three types of carbon fibers/epoxy resin composite as well as their corresponding desized carbon fiber composites subjecting to hygrothermal conditions were investigated by means of single fiber fragmentation test. The interfacial fracture energy was obtained to evaluate the interfacial bonding before and after boiling water aging. The surface characteristics of the studied carbon fiber were characterized using X-ray photoelectron spectroscopy. The effects of activated carbon atoms and silicon element at carbon fiber surface on the interfacial hygrothermal resistance were further discussed. The results show that the three carbon fiber composites with the same resin matrix possess different hygrothermal resistances of interface and the interfacial fracture energy after water aging can not recovery to the level of raw dry sample (irreversible changes) for the carbon fiber composites containing silicon. Furthermore, the activated carbon atoms have little impact on the interfacial hygrothermal resistance. The irreversible variations of interfacial bonding and the differences among different carbon fiber composites are attributed to the silicon element on the carbon fiber bodies, which might result in hydrolyzation in boiling water treatment and degrade interfacial hygrothermal resistance.

  7. Transient liquid phase bonding of carbon steel tubes using a Cu interlayer: Characterization and comparison with amorphous Fe–B–Si interlayer bonds

    Energy Technology Data Exchange (ETDEWEB)

    Di Luozzo, Nicolas, E-mail: nicolasdiluozzo@gmail.com [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Boudard, Michel; Doisneau, Béatrice [Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Fontana, Marcelo; Arcondo, Bibiana [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

    2014-12-05

    Highlights: • Cu and Fe–B–Si foils were used as interlayers to bond steel tubes by TLPB process. • The microstructure and mechanical properties were characterized. • In Cu bonded samples, the solidification process was not systematically completed. • When using Cu foils, evidences of epitaxial solidification were observed. • Tensile tests show that Cu and Fe–B–Si bonded samples failed away from the joint. - Abstract: In the present work the transient liquid phase bonding process was performed to join seamless carbon steel tubes using commercially pure Cu interlayers. The structural and mechanical characteristics of the resulting bonds are compared with those achieved using amorphous Fe–B–Si interlayers, under the same process parameters: a holding temperature of 1300 °C, a holding time of 7 min and an applied pressure of 5 MPa. The joined tubes microstructures were characterized by direct observations – scanning electron microscopy – and diffraction techniques – electron backscatter diffraction. Chemical analysis was performed using electron probe microanalysis. Whereas the amorphous Fe-B-Si interlayer leads to a completion of the bonding process over the whole bonding area, the bond performed using a Cu interlayer achieved the completion of the bonding process only partially. As the Cu is a cementite promoter, the amount of cementite coexisting with ferrite grains is higher in the joint region (JR) – corresponding to the higher concentration of Cu – as compared with the heat affected zone (HAZ) and the base metal (BM). An opposite effect is observed when using Fe-B-Si interlayers due to the fact that the cementite is unable to form in Si enriched zones – the microstructure at the JR presents only ferrite grains. Tensile tests show that the joined tubes using Cu or Fe–B–Si interlayers failed away from the bond, at the HAZ, attaining almost the same ultimate tensile strength of the BM, in the as-received condition. Hardness

  8. Transient liquid phase bonding of carbon steel tubes using a Cu interlayer: Characterization and comparison with amorphous Fe–B–Si interlayer bonds

    International Nuclear Information System (INIS)

    Highlights: • Cu and Fe–B–Si foils were used as interlayers to bond steel tubes by TLPB process. • The microstructure and mechanical properties were characterized. • In Cu bonded samples, the solidification process was not systematically completed. • When using Cu foils, evidences of epitaxial solidification were observed. • Tensile tests show that Cu and Fe–B–Si bonded samples failed away from the joint. - Abstract: In the present work the transient liquid phase bonding process was performed to join seamless carbon steel tubes using commercially pure Cu interlayers. The structural and mechanical characteristics of the resulting bonds are compared with those achieved using amorphous Fe–B–Si interlayers, under the same process parameters: a holding temperature of 1300 °C, a holding time of 7 min and an applied pressure of 5 MPa. The joined tubes microstructures were characterized by direct observations – scanning electron microscopy – and diffraction techniques – electron backscatter diffraction. Chemical analysis was performed using electron probe microanalysis. Whereas the amorphous Fe-B-Si interlayer leads to a completion of the bonding process over the whole bonding area, the bond performed using a Cu interlayer achieved the completion of the bonding process only partially. As the Cu is a cementite promoter, the amount of cementite coexisting with ferrite grains is higher in the joint region (JR) – corresponding to the higher concentration of Cu – as compared with the heat affected zone (HAZ) and the base metal (BM). An opposite effect is observed when using Fe-B-Si interlayers due to the fact that the cementite is unable to form in Si enriched zones – the microstructure at the JR presents only ferrite grains. Tensile tests show that the joined tubes using Cu or Fe–B–Si interlayers failed away from the bond, at the HAZ, attaining almost the same ultimate tensile strength of the BM, in the as-received condition. Hardness

  9. Electronic structure, bonding and magnetic properties of transition metals in carbon nanotubes

    Science.gov (United States)

    Nguyen-Manh, Duc; Kenny, Steven; Pettifor, David; Cockayne, David

    2003-03-01

    A detailed knowledge of interaction between transition metals and graphitic lattice is very crucial for understanding metal-carbon nanosystems which have potential applications in quantum computing and magnetic data storage devices. In this talk, we first identify the shortcomings of orthogonal tight-binding representation in describing electronic structure of graphitic systems. The standard minimum basis set in this scheme is not sufficient to generate peculiar nearly free electron states see in these systems; whose amplitudes are not near atomic sites but in the region between graphitic units. By using an efficient ab-intio tight-binding formalism with double numeric with polarization basis set implemented in the program PLATO (Package for Linear-combination of Atomic Type Orbitals), we compute significantly more accurate electronic structures and bonding properties of new materials but similar to that of graphite such as fullerenes and carbon nanotubes. Benchmark calculations for molecules and for phase transformation paths in solids are found to be comparable to those obtained from typical plane-wave techniques showing that the PLATO technique can be used to perform large scale total energy minimizations and molecular dynamic simulations. This novel technique is then applied to study of transition metal (TM) atoms (Fe, Co, Ni) encapsulated inside single wall carbon nanotubes of different chiralities. For zigzag nanotubes, it is found that the encapsulating process of TM is energetically favorable for (5,0) situation which in turn has a strong link with bonding properties of ferocene-type (C_10H_10Fe) molecules. The TM atoms are found to be stable inside the armchair (3,3) tube with a local environment surrounding by 6 C atoms in similarity with the most stable position of Fe, Co and Ni on graphite sheet. Finally, spin-polarized local density functional calculations are performed for all the studied systems in order to determine the magnetic moments of TM atoms

  10. Textile Dry Cleaning Using Carbon Dioxide: Process, Apparatus and Mechanical Action

    NARCIS (Netherlands)

    Sutanto, S.

    2014-01-01

    Fabrics that are sensitive to water, may wrinkle or shrink when washed in regular washing machines and are usually cleaned by professional dry cleaners. Dry cleaning is a process of removing soils from substrate, in this case textile, using a non-aqueous solvent. The most common solvent in conventio

  11. Epoxy Enhanced by Recycled Milled Carbon Fibres in Adhesively-Bonded CFRP for Structural Strengthening

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2013-12-01

    Full Text Available This paper investigates the mechanical performance and electrical resistivity of a structural adhesive epoxy enhanced using milled carbon fibre (MCF as well as the bond performance of carbon fibre reinforced polymers (CFRP and steel adhesively bonded joints using the enhanced epoxy. The epoxy was enhanced using such MCFs with different weight ratios of 1.5%, 3% and 5%. Tensile experiments were performed on the original and enhanced epoxy specimens according to ASTM D638. More ductile process failure was found for the epoxy after modification and significant improvements of E-modulus and tensile strength were evidenced when the MCF weight ratio was larger than 1.5%. Scanning electron microscopy (SEM revealed that the failure mechanism of short MCFs pulled out from the epoxy matrix contributed to the enhancement of the mechanical performance of the epoxy. The electrical resistivity of the epoxy with MCF weight ratio of 5% was reduced by at least four orders of magnitude compared to the original epoxy, due to the conductive network formed by MCFs. Steel/CFRP double strap joints (with either CFRP sheets or CFRP laminates were prepared using the enhanced epoxy and then tested in tension, however no obvious increase in joint stiffness or strength was observed.

  12. Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Wang, Chunhui [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Liu, Yongsheng, E-mail: yongshengliu@nwpu.edu.cn [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Cheng, Laifei [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Weinan [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China); Zhang, Qing [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Yang, Xiaojun [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China)

    2015-06-15

    Highlights: • The machining depth was essentially proportional to the laser power. • The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. And the number of nanoparticles increased with the processing power as well. • It revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. • It showed that a great decrease of sp{sup 3}/sp{sup 2} after laser treatment. - Abstract: Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp{sup 3}/sp{sup 2} after laser treatment.

  13. Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

    International Nuclear Information System (INIS)

    Highlights: • The machining depth was essentially proportional to the laser power. • The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. And the number of nanoparticles increased with the processing power as well. • It revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. • It showed that a great decrease of sp3/sp2 after laser treatment. - Abstract: Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp3/sp2 after laser treatment

  14. Experiment-Based Sensitivity Analysis of Scaled Carbon-Fiber-Reinforced Elastomeric Isolators in Bonded Applications

    Directory of Open Access Journals (Sweden)

    Farshad Hedayati Dezfuli

    2016-01-01

    Full Text Available Fiber-reinforced elastomeric isolators (FREIs are a new type of elastomeric base isolation systems. Producing FREIs in the form of long laminated pads and cutting them to the required size significantly reduces the time and cost of the manufacturing process. Due to the lack of adequate information on the performance of FREIs in bonded applications, the goal of this study is to assess the performance sensitivity of 1/4-scale carbon-FREIs based on the experimental tests. The scaled carbon-FREIs are manufactured using a fast cold-vulcanization process. The effect of several factors including the vertical pressure, the lateral cyclic rate, the number of rubber layers, and the thickness of carbon fiber-reinforced layers are explored on the cyclic behavior of rubber bearings. Results show that the effect of vertical pressure on the lateral response of base isolators is negligible. However, decreasing the cyclic loading rate increases the lateral flexibility and the damping capacity. Additionally, carbon fiber-reinforced layers can be considered as a minor source of energy dissipation.

  15. Role of direct covalent bonding in enhanced heat dissipation property of flexible graphene oxide–carbon nanotube hybrid film

    International Nuclear Information System (INIS)

    The thermal conductivity of graphene oxide/multiwalled carbon nanotube (GO/MWCNT) hybrid films with and without covalent bonding is examined in this study. To fabricate chemically bonded GO/MWCNT hybrid films, chlorinated GO and amino-functionalized MWCNTs are bonded covalently. The mixtures of surface modified GO and MWCNT were filtered and then subjected to hot pressing to fabricate stacked films. Examination of these chemically bonded hybrid films reveal that chlorine-doped GO exhibits enhanced electrical properties because it creates hole charge carriers by attracting the electrons in GO towards chlorine. Enhanced electrical conductivity and low sheet resistance are observed also with increasing MWCNT loadings. On comparing the through-plane thermal properties, the chemically bonded hybrid films were found to exhibit higher thermal conductivity than do the physically bonded hybrid films because of the synergetic interaction of functional groups in GO and MWCNTs in the former films. However, excess addition of MWCNTs to the films leads to an increasing phonon scattering density and a decreased thermal conductivity. - Highlights: • Graphene oxide/carbon nanotube (GO/CNT) films are bonded covalently. • GO/CNT hybrid films are prepared through filtering and hot-pressing method. • Chemically bonded hybrid films exhibit enhanced electrical and thermal properties. • Enhanced thermal conductivity is explained according to increasing CNT contents

  16. Conversion of sewage sludge to clean solid fuel using hydrothermal carbonization: Hydrochar fuel characteristics and combustion behavior

    International Nuclear Information System (INIS)

    Highlights: • The hydrothermal carbonization of sewage sludge process is developed. • Hydrochars are solid fuels with less nitrogen and sulfur contents. • The first order combustion reaction of hydrochars is derived. • Main combustion decomposition of hydrochars is easier and more stable. • Formation pathways of hydrochars during hydrothermal carbonization are proposed. - Abstract: Conventional thermochemical treatment of sewage sludge (SS) is energy-intensive due to its high moisture content. To overcome this drawback, the hydrothermal carbonization (HTC) process was used to convert SS into clean solid fuel without prior drying. Different carbonization times were applied in order to produce hydrochars possessing better fuel properties. After the carbonization process, fuel characteristics and combustion behaviors of hydrochars were evaluated. Elemental analysis showed that 88% of carbon was recovered while 60% of nitrogen and sulfur was removed. Due to dehydration and decarboxylation reactions, hydrogen/carbon and oxygen/carbon atomic ratios reduced to 1.53 and 0.39, respectively. It was found that the fuel ratio increased to 0.18 by prolonging the carbonization process. Besides, longer carbonization time seemed to decrease oxygen containing functional groups while carbon aromaticity structure increased, thereby rendering hydrochars highly hydrophobic. The thermogravimetric analysis showed that the combustion decomposition was altered from a single stage for raw sludge to two stages for hydrochars. The combustion reaction was best fitted to the first order for both raw sludge and hydrochars. The combustion of hydrochars is expected to be easier and more stable than raw sludge because of lower activation energy and pre-exponential factor

  17. On the formation and bonding of a surface carbonate on Ni(100)

    Science.gov (United States)

    Behm, R. J.; Brundle, C. R.

    1991-09-01

    The formation, stability, adsorption geometry and electronic structure of a surface carbonate on Ni(100) have been investigated by photoemission (XPS, UPS) and temperature-programmed reaction (TPR). The core level binding energies of 531.2 eV for 0(1s) and 289.0 eV for C(1s) are comparable to those of bulk carbonates. The He(II) spectrum of the carbonate valence levels is not well defined because of the coexisting adsorbed and oxidic oxygen. The angular dependence of the carbonate core level intensities is characteristic of the carbonate being present as an overlayer species rather than a thicker surface phase. The XPS data and isotope labelled TPR experiments indicate the oxygen atoms of the carbonate to be electronically and chemically equivalent, and on this basis we favor a structure in which the carbonate is attached to the metal via all three oxygen atoms. This is supported by comparision with the core level binding energies of HCOO ab and chemisorbed CO 2,ad, which are similarly attached to the surface. From the core level angular behavior, the close similarity of core level binding energies and available vibrational spectroscopic data, a (nearly) planar geometry of the CO 3,ad on Ni(100) is concluded, which is comparable to the planar bulk carbonate anion and the planar carbonate species on Ag(110). The activation barrier for decomposition is estimated from the observed maximum in TPR at 420 K to be 25 ± 2 kcal/mol. CO 2 does not accumulate on the clean or O ad-precovered Ni(100) surface at 130 K. The stabilized, chemisorbed CO 2,ad species often observed on other metal surfaces therefore does not play a critical role for carbonate formation on Ni(100). Also a mechanism involving the disproportionation of a CO 2… CO 2,ad- dimer anion can be ruled out from TPR data. The evidence of the experiments discussed in this paper suggests that the carbonate is predominantly formed by reaction of CO 2,ad with a less stable, defect (disordered) O ad species rather

  18. Metal Nanoparticles Catalyzed Selective Carbon-Carbon Bond Activation in the Liquid Phase.

    Science.gov (United States)

    Ye, Rong; Yuan, Bing; Zhao, Jie; Ralston, Walter T; Wu, Chung-Yeh; Unel Barin, Ebru; Toste, F Dean; Somorjai, Gabor A

    2016-07-13

    Understanding the C-C bond activation mechanism is essential for developing the selective production of hydrocarbons in the petroleum industry and for selective polymer decomposition. In this work, ring-opening reactions of cyclopropane derivatives under hydrogen catalyzed by metal nanoparticles (NPs) in the liquid phase were studied. 40-atom rhodium (Rh) NPs, encapsulated by dendrimer molecules and supported in mesoporous silica, catalyzed the ring opening of cyclopropylbenzene at room temperature under hydrogen in benzene, and the turnover frequency (TOF) was higher than other metals or the Rh homogeneous catalyst counterparts. Comparison of reactants with various substitution groups showed that electron donation on the three-membered ring boosted the TOF of ring opening. The linear products formed with 100% selectivity for ring opening of all reactants catalyzed by the Rh NP. Surface Rh(0) acted as the active site in the NP. The capping agent played an important role in the ring-opening reaction kinetics. Larger particle size tended to show higher TOF and smaller reaction activation energy for Rh NPs encapsulated in either dendrimer or poly(vinylpyrrolidone). The generation/size of dendrimer and surface group also affected the reaction rate and activation energy. PMID:27322570

  19. Socioeconomic Factors Affecting Farmers’ Awareness of Clean Development Mechanism Projects: Case of Smallholder Forest Carbon Projects

    OpenAIRE

    Oscar I. Ayuya; Job K. Lagat; John M. Mironga

    2011-01-01

    The objective of the study was to identify the socio-economic and institutional factors which influence the level of awareness of Clean Development Mechanism (CDM) projects and in so doing to highlight the policy implications for the stakeholders when designing clean development mechanism projects among smallholder farmers. Findings shows that 23% of the farmers were correctly aware of the project and the results of the ordered logit model indicate that age, gender, education level, group mem...

  20. Unique chemical properties of metal-carbon bonds in metal-carboranyl and metal-carboryne complexes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The metal-carbon bonds in metal-carboranyl and metal-carboryne complexes behave very differently from those in classical organometallic complexes. The unique electronic and steric properties of ico-sahedral carboranyl moiety make the M-C bond in metal-carboranyl complexes inert toward unsaturated molecules, and on the other hand, the sterically demanding carborane cage can induce unexpected C-C coupling reactions. The M-C bonds in metal-carboryne complexes are, however, active toward various kinds of unsaturated molecules and the reactivity patterns are dependent upon the electronic configurations of the metal ions. This account provides an overview of our recent work in this area.

  1. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, John H., E-mail: john.h.cantrell@nasa.gov [Research Directorate, NASA Langley Research Center, Hampton, Virginia 23681 (United States)

    2015-03-15

    The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds) formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS) of the composite. The H-bond contributions τ to the ILSS and magnitudes K{sub N} of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The K{sub N} calculations fall in the range (2.01 – 4.67) ×10{sup 17} N m{sup −3}. The average ratio K{sub N}/|τ| is calculated to be (2.59 ± 0.043) × 10{sup 10} m{sup −1} for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of K{sub N} via a technique such as angle beam ultrasonic spectroscopy.

  2. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    International Nuclear Information System (INIS)

    The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds) formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS) of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The KN calculations fall in the range (2.01 – 4.67) ×1017 N m−3. The average ratio KN/|τ| is calculated to be (2.59 ± 0.043) × 1010 m−1 for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of KN via a technique such as angle beam ultrasonic spectroscopy

  3. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    Directory of Open Access Journals (Sweden)

    John H. Cantrell

    2015-03-01

    Full Text Available The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The KN calculations fall in the range (2.01 – 4.67 ×1017 N m−3. The average ratio KN/|τ| is calculated to be (2.59 ± 0.043 × 1010 m−1 for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of KN via a technique such as angle beam ultrasonic spectroscopy.

  4. Studies of fullerenes and carbon nanotubes by an extended bond order potential

    OpenAIRE

    Che, Jianwei; Çağin, Tahir; Goddard, William A.

    1999-01-01

    We present a novel approach to combine bond order potentials with long-range nonbond interactions. This extended bond order potential consistently takes into account bond terms and nonbond terms. It not only captures the advantages of the bond order potentials (i.e. simulating bond forming and breaking), but also systematically includes the nonbond contributions to energy and forces in studying the structure and dynamics of covalently bonded systems such as graphite, diamond, nanotubes, fulle...

  5. Clean Energy for Tomorrow: Towards Zero Emission and Carbon Free Future: A Review

    Directory of Open Access Journals (Sweden)

    Wan Ramli Wan Daud

    2011-01-01

    Full Text Available Fuel cell technology using hydrogen energy is an advanced green energy technology for the future use. This is green, sustainable, clean and very environmental friendly. Green house gases emission from industrial activities has been proven beyond doubt as the main cause of global warming and climate changes. The finite world energy supply that consists nearly 90% of fossil fuel which is depleted; an energy crisis because of widening fossil fuel production and demand gaps. Many nations responded to anticipate energy crisis by diversifying their fuel resources to include renewable and alternative energy and developing green energy technology for the future. Despite political announcements on renewable energy, fossil fuels will continue to dominate energy resources for some time to come and carbon emission will increase but global nuclear energy expansion is uncertain because of international tensions and general public fears of another Chernobyl or Fogoshima disasters or a nuclear terrorist attack. Biofuels are plagued by the conflict between crops for fuel and crops for food and there is a shift of interest towards crop biomass wastes. The further expansion of hydrogen energy is constrained by costs and safety in hydrogen transport and storage. Fuel cell research and development has shifted from older AFC, PAFC and MCFC whose entry into the market were stalled by intractable operational and durability problems, to more promising PEMFC, DMFC and SOFC. A new type of fuel cell, the microbial fuel cell (MFC is also gaining some attention because of sustainable way of simultaneously reducing BOD and COD of wastewater and provide power; combined wastewater treatment and power (CWTP. The main thrust in PEMFC research and development is cost reduction of membrane and electrocatalyst by substitution of cheap and more efficient organic-inorganic nanocomposite membranes and nanoinorganic electrocatalyst as well as lower electrocatalyst loading and cost

  6. Enrichment Planting in Secondary Forests: a Promising Clean Development Mechanism to Increase Terrestrial Carbon Sinks

    Directory of Open Access Journals (Sweden)

    Catherine Potvin

    2009-06-01

    Full Text Available With the increasing need to reduce greenhouse gas concentrations, afforestation and reforestation (A/R projects are being implemented under the Kyoto Clean Development Mechanism (CDM and under the voluntary carbon (C market. The specific objective of A/R C projects is to enhance terrestrial sinks. They could also provide low-income communities in developing countries with a source of revenue, as well as a number of ecological and social services. However, feasibility issues have hindered implementation of A/R CDMs. We propose enrichment planting (EP in old fallow using high-value native timber species as a land-use alternative and a small-scale C projects opportunity. We present EP in the context of ongoing work in a poor indigenous community in eastern Panama. We consider economic risks and advantages and concordance with existing modalities under the compliance market. The potential storage capacity for EP at the site of our study was ~113 Mg C ha-1, which is comparable to other land uses with high C storage, such as industrial teak plantations and primary forest. Because secondary forests show high aboveground biomass production, C projects using EP could harness large amounts of atmospheric C while improving diversity. Carbon projects using EP can also provide high levels of social, cultural, and ecological services by planting native tree species of traditional importance to local communities and preserving most of the secondary forest’s ecological attributes. Therefore, EP planting could be considered as a way to promote synergies between two UN Conventions: climate change and biodiversity. SÍNTESIS Con la necesidad apremiante de reducción de los gases de efecto invernadero, proyectos de aforestación y reforestación (A/R pueden implementarse bajo el Mecanismo de Desarrollo Limpio del Protocolo de Kyoto (MDL o en el contexto del mercado voluntario. El objetivo especifico de los mercados de carbono, voluntario o de compromiso, es de

  7. Carbon Bonds and the saving of energy; Bonos de carbono y el ahorro de energia

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Ramirez, Alejandro [NovaEnergia (Mexico)

    2005-07-01

    This document deals with the development of the carbon bond project, the energy saving and the entry into force of the Kyoto Protocol at a world-wide level. In this project Mexico opts for a development model in which the economic growth brakes ties with the discharge of greenhouse effect gases and in which the progress does not mean more damages to our planet. [Spanish] Este documento trata sobre el desarrollo del proyecto de bonos de carbono, ahorro de energia y la entrada en vigor del Protocolo de Kyoto a nivel mundial, en el cual Mexico opta por un modelo de desarrollo en el que el crecimiento economico esta desvinculado de la emision de gases de efecto invernadero y en donde el progreso no signifique mas danos a nuestro planeta.

  8. Fast and reversible insertion of carbon dioxide into zirconocene-alkoxide bonds. A mechanistic study.

    Science.gov (United States)

    Brink, Alice; Truedsson, Ida; Fleckhaus, André; Johnson, Magnus T; Norrby, Per Ola; Roodt, Andreas; Wendt, Ola F

    2014-06-21

    In two consecutive equilibria the compound (Cp*)2Zr(OMe)2 undergoes insertion of CO2 to form the mono- and bis-hemicarbonates. Both equilibria are exothermic but entropically disfavoured. Magnetisation transfer experiments gave kinetic data for the first equilibrium showing that the rate of insertion is overall second order with a rate constant of 3.20 ± 0.12 M(-1) s(-1), which is substantially higher than those reported for other early transition metal alkoxides, which are currently the best homogeneous catalysts for dimethyl carbonate formation from methanol and CO2. Activation parameters for the insertion reaction point to a highly ordered transition state and we interpret that as there being a substantial interaction between the CO2 and the metal during the C-O bond formation. This is supported by DFT calculations showing the lateral attack by CO2 to have the lowest energy transition state. PMID:24796283

  9. Plasma coating of carbon nanofibers for enhanced dispersion and interfacial bonding in polymer composites

    International Nuclear Information System (INIS)

    Ultrathin films of polystyrene were deposited on the surfaces of carbon nanofibers using a plasma polymerization treatment. A small percent by weight of these surface-coated nanofibers were incorporated into polystyrene to form a polymer nanocomposite. The plasma coating greatly enhanced the dispersion of the nanofibers in the polymer matrix. High-resolution transmission-electron-microscopy (HRTEM) images revealed an extremely thin film of the polymer layer (∼3 nm) at the interface between the nanofiber and matrix. Tensile test results showed considerably increased strength in the coated nanofiber composite while an adverse effect was observed in the uncoated composites; the former exhibited shear yielding due to enhanced interfacial bonding while the latter fractured in a brittle fashion

  10. Bonding Mechanisms in Resistance Microwelding of 316 Low-Carbon Vacuum Melted Stainless Steel Wires

    Science.gov (United States)

    Khan, M. I.; Kim, J. M.; Kuntz, M. L.; Zhou, Y.

    2009-04-01

    Resistance microwelding (RMW) is an important joining process used in the fabrication of miniature instruments, such as electrical and medical devices. The excellent corrosion resistance of 316 low-carbon vacuum melted (LVM) stainless steel (SS) wire makes it ideal for biomedical applications. The current study examines the microstructure and mechanical properties of crossed resistance microwelded 316LVM wire. Microtensile and microhardness testing was used to analyze the mechanical performance of welds, and fracture surfaces were examined using scanning electron microscopy. Finally, a bonding mechanism is proposed based on optimum joint breaking force (JBF) using metallurgical observations of weld cross sections. Moreover, comparisons with RMWs of Ni, Au-plated Ni, and SUS304 SS wire are discussed.

  11. Liquid crystal nanocomposites produced by mixtures of hydrogen bonded achiral liquid crystals and functionalized carbon nanotubes

    Science.gov (United States)

    Katranchev, B.; Petrov, M.; Keskinova, E.; Naradikian, H.; Rafailov, P. M.; Dettlaff-Weglikowska, U.; Spassov, T.

    2014-12-01

    The liquid crystalline (LC) nature of alkyloxybenzoic acids is preserved after adding of any mesogenic or non-mesogenic compound through hydrogen bonding. However, this noncovalent interaction provokes a sizable effect on the physical properties as, e. g. melting point and mesomorphic states. In the present work we investigate nanocomposites, prepared by mixture of the eighth homologue of p-n-alkyloxybenzoic acids (8OBA) with single-walled carbon nanotubes (SWCNT) with the purpose to modify the optical properties of the liquid crystal. We exercise optical control on the LC system by inserting SWCNT specially functionalized by carboxylic groups. Since the liquid crystalline state combines order and mobility at the molecular (nanoscale) level, molecular modification can lead to different macroscopical nanocomposite symmetry. The thermal properties of the functionalized nanocomposite are confirmed by DSC analyses. The mechanism of the interaction between surface-treated nanoparticles (functionalized nanotubes) and the liquid crystal 8OBA bent- dimer molecules is briefly discussed.

  12. Relationship between ionoluminescence emission and bond distance (M-O) in carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H. [Universidad Autonoma de Madrid, Fac. Ciencias, Dpto. Qca. Agricola, Geologia y Geoquimica, 28049, Cantoblanco, Madrid (Spain); Sil, J.L. Ruvalcaba [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico, DF (Mexico)]. E-mail: sil@fisica.unam.mx; Alvarez, M.A. [Universidad de Sevilla, Dpto. Qca. Agricola y Cristalografia, Fac. de Quimica, Sevilla (Spain); Beneitez, P. [Universidad Autonoma de Madrid, Fac. Ciencias, Dpto. Qca.-Fisica Aplicada, 28049, Cantoblanco, Madrid (Spain); Millan, M.A. [Universidad Autonoma de Madrid, Fac. Ciencias, Dpto. Qca. Agricola, Geologia y Geoquimica, 28049, Cantoblanco, Madrid (Spain); Calderon, T. [Universidad Autonoma de Madrid, Fac. Ciencias, Dpto. Qca. Agricola, Geologia y Geoquimica, 28049, Cantoblanco, Madrid (Spain)

    2006-08-15

    Ionoluminescence emission spectra induced by 2 MeV protons are reported for a range of carbonates. A major feature in these spectra, are the Mn{sup 2+} luminescence centres that appear within all the samples. The emission wavelengths for the Mn{sup 2+} are linearly correlated to the metal-oxygen bonding length, both in rhombohedral and orthorhombic lattices for the minerals studied. The Mn{sup 2+} band, is in each case related to the corresponding energy level diagram of the mineral's crystal lattice, as this ion perturbs the crystal field term, which for emission in rhombohedral calcite has a value of 1000 cm{sup -1}, and for orthorhombic sites in aragonite is 1200 cm{sup -1}.

  13. Copolymerization of Carbon–carbon Double-bond Monomer (Styrene with Cyclic Monomer (Tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Sari Fouad

    2012-12-01

    Full Text Available We reported in this work that the cationic copolymerization in one step takes place between carbon–carbon double-bond monomer styrene with cyclic monomer tetrahydrofuran. The comonomers studied belong to different families: vinylic and cyclic ether. The reaction is initiated with maghnite-H+ an acid exchanged montmorillonite as acid solid ecocatalyst. Maghnite-H+ is already used as catalyst for polymerization of many vinylic and heterocyclic monomers. The oxonium ion of tetrahydrofuran and carbonium ion of styrene propagated the reaction of copolymerization. The acetic anhydride is essential for the maintenance of the ring opening of tetrahydrofuran and the entry in copolymerization. The temperature was kept constant at 40°C in oil bath heating for 6 hours. A typical reaction product was analyzed by 1H-NMR, 13C-NMR and IR and the formation of the copolymer was confirmed. The reaction was proved by matched with analysis. The maghnite-H+ allowed us to obtain extremely pure copolymer in good yield by following a simples operational conditions. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 29th October 2012; Revised: 29th November 2012; Accepted: 29th November 2012[How to Cite: S. Fouad, M.I. Ferrahi, M. Belbachir. (2012. Copolymerization of Carbon–carbon Double-bond Monomer (Styrene with Cyclic Monomer (Tetrahydrofuran. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 165-171. (doi:10.9767/bcrec.7.2.4074.165-171][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4074.165-171 ] | View in 

  14. Concurrent Formation of Carbon-Carbon Bonds and Functionalized Graphene by Oxidative Carbon-Hydrogen Coupling Reaction.

    Science.gov (United States)

    Morioku, Kumika; Morimoto, Naoki; Takeuchi, Yasuo; Nishina, Yuta

    2016-01-01

    Oxidative C-H coupling reactions were conducted using graphene oxide (GO) as an oxidant. GO showed high selectivity compared with commonly used oxidants such as (diacetoxyiodo) benzene and 2,3-dichloro-5,6-dicyano-p-benzoquinone. A mechanistic study revealed that radical species contributed to the reaction. After the oxidative coupling reaction, GO was reduced to form a material that shows electron conductivity and high specific capacitance. Therefore, this system could concurrently achieve two important reactions: C-C bond formation via C-H transformation and production of functionalized graphene. PMID:27181191

  15. Effect of curvature on C-F bonding in fluorinated carbons: from fullerene and derivatives to graphite.

    Science.gov (United States)

    Zhang, W; Dubois, M; Guérin, K; Bonnet, P; Kharbache, H; Masin, F; Kharitonov, A P; Hamwi, A

    2010-02-14

    The effect of the curvature of the carbon lattice is discussed taking into account NMR data on various fluorinated carbons including C(60) fullerenes, single, double and multiwall carbon nanotubes. Graphite fluorides and highly fluorinated fullerenes are used as limit model compounds for planar and spherical geometries, respectively. The curvature results in a weakening of the C-F bonding covalence. First of all, various highly fluorinated fullerenes with increasing F/C molar ratio were prepared by treatment with pure gaseous fluorine. A preliminary study using XRD, EPR and IR spectroscopy confirms that the highest fluorination level can be reached either at 133 or at 300 degrees C. In order to extract the correlation between fluorine and carbon atoms and the C-F bond length, specific sequences such as solid echo, two-dimensional (19)F -->(13)C cross polarization wide-line separation and inverse (19)F -->(13)C cross polarization were also used for fluorinated C(60). PMID:20119617

  16. In vitro characterization of a phosphate starvation-independent carbon-phosphorus bond cleavage activity in Pseudomonas fluorescens 23F.

    OpenAIRE

    McMullan, G.; Quinn, J P

    1994-01-01

    A novel, metal-dependent, carbon-phosphorus bond cleavage activity, provisionally named phosphonoacetate hydrolase, was detected in crude extracts of Pseudomonas fluorescens 23F, an environmental isolate able to utilize phosphonoacetate as the sole carbon and phosphorus source. The activity showed unique specificity toward this substrate; its organic product, acetate, was apparently metabolized by the glyoxylate cycle enzymes of the host cell. Unlike phosphonatase, which was also detected in ...

  17. Clean Restructuring: Design Elements for Low Carbon Wholesale Markets and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-01

    Countries around the world are in various stages of power system reform and restructuring to more effectively meet development goals and decarbonization commitments. Changes in social dynamics, technology, business models, and environmental goals are increasing pressure for countries to consider improvements to their power systems. This brochure overviews the 21st Century Power Partnerships thought leadership report that explores the clean restructuring pathway in depth, envisions an end state, and articulates three main areas of consideration for decision makers embarking on a clean restructuring process. The report also details case studies from Germany, Denmark, and Mexico.

  18. Detection of carbon-fluorine bonds in organofluorine compounds by Raman spectroscopy using a copper-vapor laser

    Science.gov (United States)

    Sharts, Clay M.; Gorelik, Vladimir S.; Agoltsov, A. M.; Zlobina, Ludmila I.; Sharts, Olga N.

    1999-02-01

    The Raman spectra of fluoro-organic compounds show specific emission bands for carbon-fluorine bonds in the range 500- 800 wave numbers (cm-1)). With very limited exceptions, biological materials do not contain carbon- fluorine bonds. Fluoro-organic compounds introduced into biological samples can be detected by a Raman emission signal. Normal mode C-F bond bands are observed: (1) at 710- 785 cm -1 for trifluoromethyl groups; (2) at 530-610 cm -1 for aromatic organofluorine bonds; (3) a range centered at 690 cm -1 for difluoromethylene groups. Specific examples of normal mode C-F bond emissions for organofluorine compounds containing trifluoromethyl groups are: 1-bromoperfluorooctane, 726 cm -1; perfluorodecanoic acid, 730 cm -1; triperfluoropropylamine, 750 cm -1; 1,3,5-tris- (trifluoromethyl)-benzene, 730 cm -1; Fluoxetine (Prozac) commercial powdered pill at 782 cm -1. Compounds containing aromatic C-F bonds are: hexafluorobenzene, 569 cm MIN1; pentafluoropyridine, 589 cm -1. Difluoromethylene groups: perfluorodecalin, 692 cm-1; perfluorocyclohexane, 691 cm -1. Raman spectra were observed with a standard single monochromator. The 510.8 nm light source was a copper-vapor laser operated at 3-10 watts with 10-12 nanosecond pulses at 10 kHz repetition rate. Detection was made with a time-gated photomultiplier tube. Resonance Raman spectra were also observed at 255.4 nm, using a frequency doubling crystal. Observed spectra were free of fluorescence with very sharp strong C-F lines.

  19. Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

    Science.gov (United States)

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning. PMID:24456468

  20. The solvent effect on the electrocatalytic cleavage of carbon-halogen bonds on Ag and Au

    International Nuclear Information System (INIS)

    In recent years it has been shown in detail how the electrocatalytic cleavage of carbon-halogen bonds is modulated by (a) the stepwise or concerted nature of the dissociative electron-transfer mechanism, which is influenced by the nature of the electrode surface, the type of halogen atom and the molecular structure of RX as a whole, and (b) the double-layer structure (as a function of the nature and bulkiness of the supporting electrolyte ions). In order to both complete and support the interpretative scheme thus developed, this work is focused on the solvent role. When one compares aprotic with protic organic solvents after appropriate intersolvental normalization, interesting peculiarities emerge, especially concerning protic media. Solvent proticity deeply affects both the reaction mechanism (on both non-catalytic and catalytic electrodes) and the extent of the catalytic effects. These items are discussed on the basis of a complete investigation carried out with a carefully controlled experimental protocol on two chloride and bromide couples, one aromatic and one aliphatic, representative of stepwise and concerted mechanisms, respectively, in four aprotic and four protic solvents, on both non−catalytic GC and catalytic Ag and Au electrodes. The results are discussed in the framework of a recently developed interpretative scheme of the carbon-halogen cleavage mechanism

  1. Mediatorless solar energy conversion by covalently bonded thylakoid monolayer on the glassy carbon electrode.

    Science.gov (United States)

    Lee, Jinhwan; Im, Jaekyun; Kim, Sunghyun

    2016-04-01

    Light reactions of photosynthesis that take place in thylakoid membranes found in plants or cyanobacteria are among the most effective ways of utilizing light. Unlike most researches that use photosystem I or photosystem II as conversion units for converting light to electricity, we have developed a simple method in which the thylakoid monolayer was covalently immobilized on the glassy carbon electrode surface. The activity of isolated thylakoid membrane was confirmed by measuring evolving oxygen under illumination. Glassy carbon surfaces were first modified with partial or full monolayers of carboxyphenyl groups by reductive C-C coupling using 4-aminobenzoic acid and aniline and then thylakoid membrane was bioconjugated through the peptide bond between amine residues of thylakoid and carboxyl groups on the surface. Surface properties of modified surfaces were characterized by cyclic voltammetry, contact angle measurements, and electrochemical impedance spectroscopy. Photocurrent of 230 nA cm(-2) was observed when the thylakoid monolayer was formed on the mixed monolayer of 4-carboxylpheny and benzene at applied potential of 0.4V vs. Ag/AgCl. A small photocurrent resulted when the 4-carboxyphenyl full monolayer was used. This work shows the possibility of solar energy conversion by directly employing the whole thylakoid membrane through simple surface modification. PMID:26625272

  2. C₂H₅OH· · ·HX (X=OH, SH, F) interactions: Is there a carbon bond?

    Indian Academy of Sciences (India)

    AMAR BAHADUR G C; RAJENDRA PARAJULI

    2016-08-01

    Computational study of ethanol complexes with H₂O, H₂S and HF molecules has been carried out using a MP2 level of theory. Carbon bonding and hydrogen bonding interactions have been analyzed in this study for all the complexes. The interaction between the carbon atom of CH₂ group of ethanol and electron-rich centre of other molecules such as the O atom of water has been found. In addition to C· · ·X interaction, CH· · ·X interaction has also been observed for all the complexes. Ab initio calculations and Atoms in Molecules (AIM) theoretical calculations confirm this. The hydrogen bonding interactions with the OH group of ethanol have also been analyzed.

  3. Trading carbon tradable offsets under Kyoto's clean development mechanism. The economic advantages to buyers and sellers of using call options

    International Nuclear Information System (INIS)

    Under the Kyoto Protocol's clean development mechanism, developed countries may purchase or trade for emission reduction units or greenhouse gas (GHG) offsets originating either from excess quota allocations or from developing countries' projects. Selling emission reduction units before a market has actually developed presents pricing problems for both sellers and buyers. In the case of sequestered carbon and in the example of a Costa Rican project, it may be economically beneficial to both buyer and seller alike for the buyer to purchase the right, but not the obligation, to purchase a carbon tradable offset (CTO). It is shown by valuing purchases and sales of CTO options that advantages from such an instrument are possible to both seller and buyer at least until a true market in GHG offset trading develops. 16 refs

  4. Black Carbon and Kerosene Lighting: An Opportunity for Rapid Action on Climate Change and Clean Energy for Development

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Arne [Humboldt State Univ., MN (United States). Schatz Energy Research Center; Bond, Tami C. [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Civil and Environmental Engineering; Lam, Nicholoas L. [Univ. of California, Berkeley, CA (United States). Dept. of Environmental Health Sciences; Hultman, Nathan [The Brookings Institution, Washington, DC (United States)

    2013-04-15

    Replacing inefficient kerosene lighting with electric lighting or other clean alternatives can rapidly achieve development and energy access goals, save money and reduce climate warming. Many of the 250 million households that lack reliable access to electricity rely on inefficient and dangerous simple wick lamps and other kerosene-fueled light sources, using 4 to 25 billion liters of kerosene annually to meet basic lighting needs. Kerosene costs can be a significant household expense and subsidies are expensive. New information on kerosene lamp emissions reveals that their climate impacts are substantial. Eliminating current annual black carbon emissions would provide a climate benefit equivalent to 5 gigatons of carbon dioxide reductions over the next 20 years. Robust and low-cost technologies for supplanting simple wick and other kerosene-fueled lamps exist and are easily distributed and scalable. Improving household lighting offers a low-cost opportunity to improve development, cool the climate and reduce costs.

  5. Methods of making non-covalently bonded carbon-titania nanocomposite thin films and applications of the same

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yu Teng; Vijayan, Baiju K.; Gray, Kimberly A.; Hersam, Mark C.

    2016-07-19

    In one aspect, a method of making non-covalently bonded carbon-titania nanocomposite thin films includes: forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

  6. Ultra hydrophobic/superhydrophilic modified cotton textiles through functionalized diamond-like carbon coatings for self-cleaning applications.

    Science.gov (United States)

    Caschera, Daniela; Cortese, Barbara; Mezzi, Alessio; Brucale, Marco; Ingo, Gabriel Maria; Gigli, Giuseppe; Padeletti, Giuseppina

    2013-02-26

    A stable and improved control of the wettability of textiles was obtained by using a coating of diamond like carbon (DLC) films on cotton by PECVD. By controlling different plasma pretreatments of argon, oxygen, and hydrogen on the cotton fibers' surface, we have shown that the pretreatments had a significant impact on wettability behavior resulting from an induced nanoscale roughness combined with an incorporation of selected functional groups. Upon subsequent deposition of diamond like carbon (DLC) films, the cotton fibers yield to a highly controlled chemical stability and hydrophobic state and could be used for self-cleaning applications. By controlling the nature of the plasma pretreatment we have shown that the oxygen plasma pretreatment was more effective than the argon and hydrogen for the superhydrophilic/ultra hydrophobic properties. The chemical and morphological changes of the cotton fibers under different treatments were characterized using X-ray photoelectron and Raman spectroscopy, AFM, and water contact angle measurements. The mechanism underlying the water-repellent properties of the cotton fibers provides a new and innovative pathway into the development of a range of advanced self-cleaning textiles. PMID:23379650

  7. Wire bonding in microelectronics

    CERN Document Server

    Harman, George G

    2010-01-01

    Wire Bonding in Microelectronics, Third Edition, has been thoroughly revised to help you meet the challenges of today's small-scale and fine-pitch microelectronics. This authoritative guide covers every aspect of designing, manufacturing, and evaluating wire bonds engineered with cutting-edge techniques. In addition to gaining a full grasp of bonding technology, you'll learn how to create reliable bonds at exceedingly high yields, test wire bonds, solve common bonding problems, implement molecular cleaning methods, and much more. Coverage includes: Ultrasonic bonding systems and technologies, including high-frequency systems Bonding wire metallurgy and characteristics, including copper wire Wire bond testing Gold-aluminum intermetallic compounds and other interface reactions Gold and nickel-based bond pad plating materials and problems Cleaning to improve bondability and reliability Mechanical problems in wire bonding High-yield, fine-pitch, specialized-looping, soft-substrate, and extreme-temperature wire bo...

  8. Carbon nanotube-bonded graphene hybrid aerogels and their application to water purification

    Science.gov (United States)

    Lee, Byeongho; Lee, Sangil; Lee, Minwoo; Jeong, Dae Hong; Baek, Youngbin; Yoon, Jeyong; Kim, Yong Hyup

    2015-04-01

    We present carbon nanotube (CNT)-bonded graphene hybrid aerogels that are prepared by growing CNTs on a graphene aerogel surface with nickel catalyst. The presence of bonded CNTs in the graphene aerogel results in vastly improved mechanical and electrical properties. A significant increase in specific surface area is also realized. The presence of the CNTs transforms the hybrid aerogels into a mesoporous material. The viscoelasticity of the hybrid aerogels is found to be invariant with respect to temperature over a range of between -150 °C and 450 °C. These characteristics along with the improved properties make the hybrid aerogels an entirely different class of material with applications in the fields of biotechnology and electrochemistry. The mesoporous nature of the material along with its high specific surface area also makes the hybrid aerogel attractive for application in water treatment. Both anionic and cationic dyes can be effectively removed from water by the hybrid aerogel. A number of organics and oils can be selectively separated from water by the hybrid aerogel. The hybrid aerogel is easy to handle and separate from water due to its magnetic nature, and can readily be recycled and reused.We present carbon nanotube (CNT)-bonded graphene hybrid aerogels that are prepared by growing CNTs on a graphene aerogel surface with nickel catalyst. The presence of bonded CNTs in the graphene aerogel results in vastly improved mechanical and electrical properties. A significant increase in specific surface area is also realized. The presence of the CNTs transforms the hybrid aerogels into a mesoporous material. The viscoelasticity of the hybrid aerogels is found to be invariant with respect to temperature over a range of between -150 °C and 450 °C. These characteristics along with the improved properties make the hybrid aerogels an entirely different class of material with applications in the fields of biotechnology and electrochemistry. The mesoporous nature

  9. Use of magnetic carbon composites from renewable resource materials for oil spill clean up and recovery

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Tito

    2015-10-27

    A method of separating a liquid hydrocarbon material from a body of water, includes: (a) mixing magnetic carbon-metal nanocomposites with a liquid hydrocarbon material dispersed in a body of water to allow the magnetic carbon-metal nanocomposites each to be adhered by the liquid hydrocarbon material to form a mixture; (b) applying a magnetic force to the mixture to attract the magnetic carbon-metal nanocomposites each adhered by the liquid hydrocarbon material; and (c) removing the body of water from the magnetic carbon-metal nanocomposites each adhered by the liquid hydrocarbon material while maintaining the applied magnetic force. The magnetic carbon-metal nanocomposites is formed by subjecting one or more metal lignosulfonates or metal salts to microwave radiation, in presence of lignin/derivatives either in presence of alkali or a microwave absorbing material, for a period of time effective to allow the carbon-metal nanocomposites to be formed.

  10. Conversion of carbon dioxide to valuable petrochemicals:An approach to clean development mechanism

    Institute of Scientific and Technical Information of China (English)

    Farnaz Tahriri Zangeneh; Saeed Sahebdelfar; Maryam Takht Ravanchi

    2011-01-01

    The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea.The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases,modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.

  11. Clean Energy for Tomorrow: Towards Zero Emission and Carbon Free Future: A Review

    OpenAIRE

    Wan Ramli Wan Daud; Ghasem Najafpour; Mostafa Rahimnejad

    2011-01-01

    Fuel cell technology using hydrogen energy is an advanced green energy technology for the future use. This is green, sustainable, clean and very environmental friendly. Green house gases emission from industrial activities has been proven beyond doubt as the main cause of global warming and climate changes. The finite world energy supply that consists nearly 90% of fossil fuel which is depleted; an energy crisis because of widening fossil fuel production and demand gaps. Many nations responde...

  12. The mechanical bond on carbon nanotubes: diameter-selective functionalization and effects on physical properties

    Science.gov (United States)

    Martínez-Periñán, Emiliano; de Juan, Alberto; Pouillon, Yann; Schierl, Christoph; Strauss, Volker; Martín, Nazario; Rubio, Ángel; Guldi, Dirk M.; Lorenzo, Encarnación; Pérez, Emilio M.

    2016-04-01

    We describe the functionalization of SWNTs enriched in (6,5) chirality with electron donating macrocycles to yield rotaxane-type mechanically interlocked carbon nanotubes (MINTs). Investigations by means of electron microscopy and control experiments corroborated the interlocked nature of the MINTs. A comprehensive characterization of the MINTs through UV-vis-NIR, Raman, fluorescence, transient absorption spectroscopy, cyclic voltammetry, and chronoamperometry was carried out. Analyses of the spectroscopic data reveal that the MINT-forming reaction proceeds with diameter selectivity, favoring functionalization of (6,5) SWNTs rather than larger (7,6) SWNTs. In the ground state, we found a lack of significant charge-transfer interactions between the electron donor exTTF and the SWNTs. Upon photoexcitation, efficient charge-transfer between the electron donating exTTF macrocycles and SWNTs was demonstrated. As a complement, we established significantly different charge-transfer rate constants and diffusion coefficients for MINTs and the supramolecular models, which confirms the fundamentally different type of interactions between exTTF and SWNTs in the presence or absence of the mechanical bond. Molecular mechanics and DFT calculations support the experimental findings.We describe the functionalization of SWNTs enriched in (6,5) chirality with electron donating macrocycles to yield rotaxane-type mechanically interlocked carbon nanotubes (MINTs). Investigations by means of electron microscopy and control experiments corroborated the interlocked nature of the MINTs. A comprehensive characterization of the MINTs through UV-vis-NIR, Raman, fluorescence, transient absorption spectroscopy, cyclic voltammetry, and chronoamperometry was carried out. Analyses of the spectroscopic data reveal that the MINT-forming reaction proceeds with diameter selectivity, favoring functionalization of (6,5) SWNTs rather than larger (7,6) SWNTs. In the ground state, we found a lack of

  13. Purification, molecular cloning, and expression of 2-hydroxyphytanoyl- CoA lyase, a peroxisomal thiamine pyrophosphate-dependent enzyme that catalyzes the carbon-carbon bond cleavage during à-oxidation of 3- methyl-branched fatty acids

    CERN Document Server

    Foulon, V; Croes, K; Waelkens, E

    1999-01-01

    Purification, molecular cloning, and expression of 2-hydroxyphytanoyl- CoA lyase, a peroxisomal thiamine pyrophosphate-dependent enzyme that catalyzes the carbon-carbon bond cleavage during à-oxidation of 3- methyl-branched fatty acids

  14. Low carbon and clean energy scenarios for India: Analysis of targets approach

    International Nuclear Information System (INIS)

    Low carbon energy technologies are of increasing importance to India for reducing emissions and diversifying its energy supply mix. Using GCAM, an integrated assessment model, this paper analyzes a targets approach for pushing solar, wind, and nuclear technologies in the Indian electricity generation sector from 2005 to 2095. Targets for these technologies have been constructed on the basis of Indian government documents, policy announcements, and expert opinions. Different targets have been set for the reference scenario and the carbon price scenario. In the reference scenario, wind and nuclear technologies exceed respective targets in the long run without any subsidy push, while solar energy requires subsidy push throughout the century in order to meet its high targets. In the short run, nuclear energy also requires significant subsidy, including a much higher initial subsidy relative to solar power, which is a result of its higher targets. Under a carbon price scenario, the carbon price drives the penetration of these technologies. Still, subsidy is required — especially in the short run when the carbon price is low. We also found that pushing solar, wind, and nuclear technologies leads to a decrease in share of CCS under the carbon price scenario and biomass under both the reference and carbon price scenarios. This is because low carbon technologies compete among themselves and substitute each other, thereby enhancing the need for subsidy or carbon price, highlighting that proposed targets are not set at efficient levels. In light of contemporary debate on external costs of nuclear energy, we also assess the sensitivity of the results to nuclear technology cost. We find that higher cost significantly decreases the share of nuclear power under both the reference and carbon price scenarios.

  15. The Bonding of NO2, NH3, and CH2NY to Models of a (10,0) Carbon Nanotube

    Science.gov (United States)

    Walch, Stephen P.

    2004-01-01

    We have studied the bonding of NO2, NH3, and CH2NH to a (10,O) carbon nanotube using the MP2 and ONIOM methods with extended basis sets. We find bond strengths of 3.5, 3.6. and 6.3 kcal/mol for NO2, NH3, and CH2NH, respectively, using the ONIOM method with the high accuracy part treated at the MP2/aug-CC-pVTZ level and the remainder of the CNT approximated at the UFF level and including an estimate of basis set superposition error using the counterpoise method.

  16. Mineral-Based Bonding of Carbon FRP to Strengthen Concrete Structures

    DEFF Research Database (Denmark)

    Täljsten, Björn; Blanksvärd, T.

    2007-01-01

    therefore be strengthened before it can be used. Different methods to retrofit with FRPs also exist, such as bonding of plates or sheets, with their use of epoxy as the bonding agent being the commonality. Epoxy provides very good bond to concrete and is durable and resistant to most environments in the...

  17. Activation of the carbon-fluorine bonds in coordination compounds; Activacion de enlaces carbon-fluor en compuestos de coordinacion

    Energy Technology Data Exchange (ETDEWEB)

    Torrens, H. [Universidad Nacional Autonoma de Mexico, Facultad de Quimica, 04510 Mexico D.F. (Mexico)

    2000-07-01

    Activation of the carbon-fluorine bond is of upmost importance in several chemical processes. In search of synthetic alternatives to promote C-F bond cleavage in arylic systems, several square planar palladium and platinum compounds bearing fluorothiolates and fluorophosphines have been studied. In this paper molecular structures are shown for the following compounds trans-((SC{sub 6}F{sub 5})(P(C{sub 6}F{sub 5}){sub 2}(C{sub 6}H{sub 5}))(Pd({mu}-SC{sub 6}F{sub 5}){sub 2} Pd(SC{sub 6}F{sub 5})(P(C{sub 6}F{sub 5}){sub 2} (C{sub 6}H{sub 5})), cis ((SC{sub 6}F{sub 5}) P(C{sub 6}F{sub 5}){sub 2} (C{sub 6}H{sub 5}) Pt({mu}-SC{sub 6}F{sub 5}){sub 2} Pt(SC{sub 6}F{sub 5}) P(C{sub 6}F{sub 5}){sub 2} (C{sub 6}H{sub 5})), trans Pd ({mu}-SC{sub 6}F{sub 5}){sub 2} Pt(SC{sub 6}F{sub 5})(P(C{sub 6}F{sub 5})(C{sub 6}H{sub 5}){sub 2})), Pt (SC{sub 6}F{sub 5}){sub 2} (C{sub 6}F{sub 5}SC{sub 6}F{sub 4} P(C{sub 6}H{sub 5}){sub 2}))((SC{sub 6}F{sub 5}){sub 2} Pt ({mu}-(SC{sub 6}F{sub 5}){sub 2} Pt(SC{sub 6}F{sub 5}){sub 2}){sup 2-} , (SC{sub 6}HF{sub 4}){sub 2} Pt({mu}-SC{sub 6}HF{sub 4}){sub 2} Pt(SC{sub 6}HF{sub 4}){sub 2}){sup 2-} and ((SC{sub 6}F{sub 4}CF{sub 3}-4){sub 2} Pt (SC{sub 6}F{sub 4}CF{sub 3}-4){sub 2}){sup 2-} . (Author)

  18. Carbon-sulfur bond-forming reaction catalysed by the radical SAM enzyme HydE.

    Science.gov (United States)

    Rohac, Roman; Amara, Patricia; Benjdia, Alhosna; Martin, Lydie; Ruffié, Pauline; Favier, Adrien; Berteau, Olivier; Mouesca, Jean-Marie; Fontecilla-Camps, Juan C; Nicolet, Yvain

    2016-05-01

    Carbon-sulfur bond formation at aliphatic positions is a challenging reaction that is performed efficiently by radical S-adenosyl-L-methionine (SAM) enzymes. Here we report that 1,3-thiazolidines can act as ligands and substrates for the radical SAM enzyme HydE, which is involved in the assembly of the active site of [FeFe]-hydrogenase. Using X-ray crystallography, in vitro assays and NMR spectroscopy we identified a radical-based reaction mechanism that is best described as the formation of a C-centred radical that concomitantly attacks the sulfur atom of a thioether. To the best of our knowledge, this is the first example of a radical SAM enzyme that reacts directly on a sulfur atom instead of abstracting a hydrogen atom. Using theoretical calculations based on our high-resolution structures we followed the evolution of the electronic structure from SAM through to the formation of S-adenosyl-L-cysteine. Our results suggest that, at least in this case, the widely proposed and highly reactive 5'-deoxyadenosyl radical species that triggers the reaction in radical SAM enzymes is not an isolable intermediate. PMID:27102684

  19. Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

    Directory of Open Access Journals (Sweden)

    Matthieu Jouffroy

    2014-10-01

    Full Text Available The capacity of two cavity-shaped ligands, HUGPHOS-1 and HUGPHOS-2, to generate exclusively singly phosphorus-ligated complexes, in which the cyclodextrin cavity tightly wraps around the metal centre, was explored with a number of late transition metal cations. Both cyclodextrin-derived ligands were assessed in palladium-catalysed Mizoroki–Heck coupling reactions between aryl bromides and styrene on one hand, and the rhodium-catalysed asymmetric hydroformylation of styrene on the other hand. The inability of both chiral ligands to form standard bis(phosphine complexes under catalytic conditions was established by high-pressure NMR studies and shown to have a deep impact on the two carbon–carbon bond forming reactions both in terms of activity and selectivity. For example, when used as ligands in the rhodium-catalysed hydroformylation of styrene, they lead to both high isoselectivity and high enantioselectivity. In the study dealing with the Mizoroki–Heck reactions, comparative tests were carried out with WIDEPHOS, a diphosphine analogue of HUGPHOS-2.

  20. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

    Directory of Open Access Journals (Sweden)

    G. Sarwar

    2013-03-01

    Full Text Available We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2 into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, peroxyacetyl nitrate by 40%, and organic nitrate by 41%. RACM2 predictions generally agree better with the observed data than the CB05TU predictions. RACM2 enhances ozone for all ambient levels leading to higher bias at low (70 ppbv concentrations. The RACM2 ozone predictions are also supported by increased ozone production efficiency that agrees better with observations. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean sulfate by 10%, nitrate by 6%, ammonium by 10%, anthropogenic secondary organic aerosols by 42%, biogenic secondary organic aerosols by 5%, and in-cloud secondary organic aerosols by 7%. Increased inorganic and organic aerosols with RACM2 agree better with observed data. While RACM2 enhances ozone and secondary aerosols by relatively large margins, control strategies developed for ozone or fine particles using the two mechanisms do not differ appreciably.

  1. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

    Directory of Open Access Journals (Sweden)

    G. Sarwar

    2013-10-01

    Full Text Available We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2 into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, peroxyacetyl nitrate by 40%, and organic nitrate by 41%. RACM2 enhances ozone compared to CB05TU at all ambient levels. Although it exhibited greater overestimates at lower observed concentrations, it displayed an improved performance at higher observed concentrations. The RACM2 ozone predictions are also supported by increased ozone production efficiency that agrees better with observations. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean sulfate by 10%, nitrate by 6%, ammonium by 10%, anthropogenic secondary organic aerosols by 42%, biogenic secondary organic aerosols by 5%, and in-cloud secondary organic aerosols by 7%. Increased inorganic and organic aerosols with RACM2 agree better with observed data. Any air pollution control strategies developed using the two mechanisms do not differ appreciably.

  2. Filamentous carbon particles for cleaning oil spills and method of production

    Science.gov (United States)

    Muradov, Nazim

    2010-04-06

    A compact hydrogen generator is coupled to or integrated with a fuel cell for portable power applications. Hydrogen is produced via thermocatalytic decomposition (cracking, pyrolysis) of hydrocarbon fuels in oxidant-free environment. The apparatus can utilize a variety of hydrocarbon fuels, including natural gas, propane, gasoline, kerosene, diesel fuel, crude oil (including sulfurous fuels). The hydrogen-rich gas produced is free of carbon oxides or other reactive impurities, so it could be directly fed to any type of a fuel cell. The catalysts for hydrogen production in the apparatus are carbon-based or metal-based materials and doped, if necessary, with a sulfur-capturing agent. Additionally disclosed are two novel processes for the production of two types of carbon filaments, and a novel filamentous carbon product. The hydrogen generator can be conveniently integrated with high temperature fuel cells to produce an efficient and self-contained source of electrical power.

  3. Supercritical carbon dioxide (SC-CO2 as a clean technology for palm kernel oil extraction

    Directory of Open Access Journals (Sweden)

    Norhuda I

    2009-04-01

    Kyoto Protocol. Keywords: By-product, Solvent extraction, Kyoto protocol, Supercritical Carbon Dioxide, Palm Kernel Oil Received: 13 July 2008 / Received in revised form: 17 February 2009, Accepted: 28 February 2009, Published online: 12 March 2009

  4. Cleaning the Bathwater with the Baby: The Health Co-Benefits of Carbon Pricing in Transportation

    OpenAIRE

    Christopher R. Knittel; Ryan Sandler

    2011-01-01

    Efforts to reduce greenhouse gas emissions in the US have relied on Corporate Average Fuel Economy (CAFE) Standards and Renewable Fuel Standards (RFS). Economists often argue that these policies are inefficient relative to carbon pricing because they ignore existing vehicles and do not adequately reduce the incentive to drive. This paper presents evidence that the net social costs of carbon pricing are significantly less than previous thought. The bias arises from the fact that the demand ela...

  5. Study of the damaging mechanisms of a carbon - carbon composite bonded to copper under thermomechanical loading; Etude des mecanismes d'endommagement d'un assemblage cuivre / composite carbone - carbone sous chargement thermomecanique

    Energy Technology Data Exchange (ETDEWEB)

    Moncel, L

    1999-06-15

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM 2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterisation. (author)

  6. Mechanically durable carbon nanotube-composite hierarchical structures with superhydrophobicity, self-cleaning, and low-drag.

    Science.gov (United States)

    Jung, Yong Chae; Bhushan, Bharat

    2009-12-22

    Superhydrophobic surfaces with high contact angle and low contact angle hysteresis exhibit a self-cleaning effect and low drag for fluid flow. The lotus (Nelumbo nucifera) leaf is one of the examples found in nature for superhydrophobic surfaces. For the development of superhydrophobic surfaces, which is important for various applications such as glass windows, solar panels, and microchannels, materials and fabrication methods need to be explored to provide mechanically durable surfaces. It is necessary to perform durability studies on these surfaces. Carbon nanotube (CNT), composite structures which would lead to superhydrophobicity, self-cleaning, and low-drag, were prepared using a spray method. As a benchmark, structured surfaces with lotus wax were also prepared to compare with the durability of CNT composite structures. To compare the durability of the various fabricated surfaces, waterfall/jet tests were conducted to determine the loss of superhydrophobicity by changing the flow time and pressure conditions. Wear and friction studies were also performed using an atomic force microscope (AFM) and a ball-on-flat tribometer. The changes in the morphology of the structured surfaces were examined by AFM and optical imaging. We find that superhydrophobic CNT composite structures showed good mechanical durability, superior to the structured surfaces with lotus wax, and may be suitable for real world applications. PMID:19947581

  7. Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot-Molecular Catalyst Photosystem.

    Science.gov (United States)

    Martindale, Benjamin C M; Joliat, Evelyne; Bachmann, Cyril; Alberto, Roger; Reisner, Erwin

    2016-08-01

    Carbon quantum dots (CQDs) are new-generation light absorbers for photocatalytic H2 evolution in aqueous solution, but the performance of CQD-molecular catalyst systems is currently limited by the decomposition of the molecular component. Clean oxidation of the electron donor by donor recycling prevents the formation of destructive radical species and non-innocent oxidation products. This approach allowed a CQD-molecular nickel bis(diphosphine) photocatalyst system to reach a benchmark lifetime of more than 5 days and a record turnover number of 1094±61 molH2  (molNi )(-1) for a defined synthetic molecular nickel catalyst in purely aqueous solution under AM1.5G solar irradiation. PMID:27355200

  8. Metal, bond energy, and ancillary ligand effects on actinide-carbon σ-bond hydrogenolysis. A kinetic and mechanistic study

    International Nuclear Information System (INIS)

    A kineticmechanistic study of actinide hydrocarbyl ligand hydrogenolysis (An-R + H2 → An-H + RH) is reported. For the complex Cp'2TH(CH2-t-Bu)(O-t-Bu)(Cp' = eta5-Me5C5), the rate law is first-order in organoactinide and first-order in H2, with k/sub H2/k/sub D2/ = 2.5 (4) and k/sub THF/k/sub toluene/ = 2.9 (4). For a series of complexes, hydrogenolysis rates span a range of ca. 105 with Cp'2ThCH2C(CH3)2CH2 ≅ Cp'2U(CH2-t-Bu) (too rapid to measure accurately) > Cp'2Th(CH2-t-Bu)[OCH(t-Bu)2] = Cp'2Th(CH2-t-Bu)(O-t-Bu) > Cp'2Th(CH2-t-Bu)(Cl) > Me2Si(Me4C5)2Th(n-Bu)2 > Cp'2Th(n-Bu)2 ≅ Cp'2ThMe2 > Cp'2Th(Me)(O3SCF3) > Cp'2Th(n-Bu)[OCG(t-Bu)2] ≅ Cp'2Th(Me)[OSiMe2(t-Bu)] > Cp'2ZrMe2 = Cp'2Th(rho-C6H4NMe2)(O-tu-Bu) > Cp'2Th(Ph)(O-t-Bu) > Cp'2U(Me)[OCH(t-Bu)2] > Cp'2Th(Me)[OCH(t-Bu)2]. In the majority of cases, the rate law is cleanly first-order in organoactinide over 3 or more half-lives. However, for Cp'2ThMe2 → (Cp'2ThH2)2, an intermediate is observe by NMR that is probably [Cp'2Th(Me)(μ-H)]2. For Cp'2Th(Me)(O3SCF3), a follow-up reaction, which consumes Cp'2TH(H)(O3SCF3) is detected. Variable-temperature kinetic studies yield ΔH** = 3.7 (2) kcalmol and ΔS double dagger = -50.8 (7) eu for Cp'2Th(CH2-t-Bu)(O-t-Bu) and ΔH double dagger = 9 (2) kcalmol and ΔS double dagger = -45 (5) eu for Cp'2U(Me)[OCH(O-t-Bu)2

  9. Unexpected carbon-oxygen bond cleavage of THF promoted by guanidinate titanium complex/lithium diisopropylamide: Synthesis and crystal structure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; WANG Mei; YAO Yingming; SHEN Qi

    2005-01-01

    An unexpected carbon-oxygen bond cleavage of THF (THF = tetrahydrofuran) promoted by guanidinate titanium complex was described. Guanidinate lithium [Pr2iNC(NCy)2]Li (Cy = cyclohexyl) formed in situ reacted with TiCl4(THF)2 in a 2:1 molar ratio to produce the guanidinate titanium chloride [Pr2iNC(NCy)2]2TiCl2 (1) in good yield. The reaction of [Pr2iNC(NCy)2]2TiCl2 with lithium diisopropylamide in THF afforded an unexpected [Pr2iNC(NCy)2]2Ti(OBun)2 (2), which was formed by the cleavage of carbon-oxygen bond of THF. Complexes 1 and 2 were fully characterized by elemental analysis, NMR and IR spectroscopies, and X-ray crystal structure determination for complex 2.

  10. The effects of interfacial bonding on mechanical properties of single-walled carbon nanotube reinforced copper matrix nanocomposites

    International Nuclear Information System (INIS)

    The effects of interfacial bonding on mechanical properties of single-walled carbon nanotube reinforced copper matrix nanocomposites were investigated. The nanocomposites were fabricated by means of a powder metallurgy process, which consists of mixing carbon nanotubes with matrix powder followed by hot-pressing. The mixing process was carried out by ultrasonicating the nanotubes and copper powder in ethanol. The interfacial strength between the nanotubes and the copper matrix was improved by coating the nanotubes with nickel. The displacement rate of the nanotube reinforced nanocomposites was found to increase at 200 deg. C, whereas that of the nickel-coated nanotube reinforced nanocomposites significantly decreased. The incorporation of carbon nanotubes and nickel-coated carbon nanotubes in the copper matrix composites improved tribological properties compared with those of pure copper specimens

  11. Flexural behaviour of partially bonded carbon fibre reinforced polymers strengthened concrete beams: Application to fire protection systems design

    International Nuclear Information System (INIS)

    Highlights: • The mechanical behaviour of partially bonded CFRP strengthened beams was modelled. • Two dimensional non-linear finite element models were developed. • Partially bonded beams can present similar flexural strength to fully bonded ones. • Relations between the bonded length and the strength reduction were proposed. • The proposed relations were used for the design of fire protection systems. - Abstract: Recent fire resistance tests on reinforced concrete (RC) beams strengthened with carbon fibre reinforced polymers (CFRP) laminates showed that it is possible to attain considerable fire endurance provided that thermal insulation is applied at the anchorage zones of the strengthening system. With such protection, although the CFRP laminate prematurely debonds in the central part of the beam, it transforms into a cable fixed at the extremities until one of the anchorage zones loses its bond strength. The main objective of this paper is to propose a simplified methodology for the design of fire protection systems for CFRP strengthened-RC beams, which is based on applying thicker insulation at the anchorage zones (promoting the above mentioned “cable behaviour”) and a thinner one at the current zone (avoiding tensile rupture of the carbon fibres). As a first step towards the validation of this methodology, finite element (FE) models were developed to simulate the flexural behaviour at ambient temperature of full-scale RC beams strengthened with CFRP laminates according to the externally bonded reinforcement (EBR) and near surface mounted (NSM) techniques, in both cases fully or partially bonded (the latter simulating the cable). The FE models were calibrated with results of 4-point bending tests on small-scale beams and then extended for different beam geometries, with spans (L) varying from 2 m to 5 m, in which the influence of the CFRP bonded length (lb) and the loading type (point or uniformly distributed) on the strength reduction was

  12. Nickel-Catalyzed Carbon–Carbon Bond-Forming Reactions of Unactivated Tertiary Alkyl Halides: Suzuki Arylations

    OpenAIRE

    Zultanski, Susan L.; Fu, Gregory C.

    2013-01-01

    The first Suzuki cross-couplings of unactivated tertiary alkyl electrophiles are described. The method employs a readily accessible catalyst (NiBr[subscript 2]·diglyme/4,4′-di-tert-butyl-2,2′-bipyridine, both commercially available) and represents the initial example of the use of a group 10 catalyst to cross-couple unactivated tertiary electrophiles to form C–C bonds. This approach to the synthesis of all-carbon quaternary carbon centers does not suffer from isomerization of the alkyl group,...

  13. Effect of applied dc bias voltage on composition, chemical bonding and mechanical properties of carbon nitride films prepared by PECVD

    Institute of Scientific and Technical Information of China (English)

    LI Hong-xuan; XU Tao; HAO Jun-ying; CHEN Jian-min; ZHOU Hui-di; XUE Qun-ji; LIU Hui-wen

    2004-01-01

    Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.

  14. Regioselective carbon–carbon bond formation of 5,5,5-trifluoro-1-phenylpent-3-en-1-yne

    Directory of Open Access Journals (Sweden)

    Motoki Naka

    2013-10-01

    Full Text Available The regioselective carbon–carbon bond formation was studied using 5,5,5-trifluoro-1-phenylpent-3-en-1-yne as a model substrate, and predominant acceptance of electrophiles β to a CF3 group as well as a deuterium trap experiment of the lithiated species led to the conclusion that the obtained regioselectivity is kinetically determined for the reactions with electrophiles, under equilibration of the possible two anionic species.

  15. US power plant carbon standards and clean air and health co-benefits

    Science.gov (United States)

    Driscoll, Charles T.; Buonocore, Jonathan J.; Levy, Jonathan I.; Lambert, Kathleen F.; Burtraw, Dallas; Reid, Stephen B.; Fakhraei, Habibollah; Schwartz, Joel

    2015-06-01

    Carbon dioxide emissions standards for US power plants will influence the fuels and technologies used to generate electricity, alter emissions of pollutants such as sulphur dioxide and nitrogen oxide, and influence ambient air quality and public health. We present an analysis of how three alternative scenarios for US power plant carbon standards could change fine particulate matter and ozone concentrations in ambient air, and the resulting public health co-benefits. The results underscore that carbon standards to curb global climate change can also provide immediate local and regional health co-benefits, but the magnitude depends on the design of the standards. A stringent but flexible policy that counts demand-side energy efficiency towards compliance yields the greatest health benefits of the three scenarios analysed.

  16. Opportunities for A Low Carbon Future——China's Clean Revolution Ⅱ

    Institute of Scientific and Technical Information of China (English)

    Audrey GUO

    2009-01-01

    @@ Despite economic downturn,China's domestic markets continue to scale up low carbon technology.A new report that was released in Beijing in August by the Climate Group shows that in an incredibly short time China has taken the lcad in the race to develop and commercialize a range of low carbon technologies.On the back of ambitious government policies and a new breed of entrepreneurs,Chinese businesses are amongst the top producers of electric vehicles,wind turbines,solar panels and energy efficient appliances.

  17. Influence of different adhesive systems on bond strength of carbon fiber posts used to restore endodontically treated teeth

    Directory of Open Access Journals (Sweden)

    Lorena dos Santos Silva

    2013-12-01

    Full Text Available The aim of this study was to evaluate the influence of three adhesive systems on resinous bonding of carbon fiber posts on roots of endodontically treated bovine incisors. Thirty bovine lower incisors with similar dimensions were selected for this study. The roots were endodontically treated and subsequently prepared for post cementation. The posts were treated with adhesive systems Scotchbond MultiPurpose Plus – 3M chemical cure (Group I, light cure (Group II and dual cure (Group III. Carbon fiber posts were adjusted to 8mm and cemented in the canal with resinous dual cement RelyX ARC – 3M. Those were taken to Universal Essay Machine for the push-out shear bond strength test. Analysis of the results were made with 2-Way ANOVA and post-hoc with Tukey’s test (p<0.05. The groups were statistically different. The chemical cure adhesive system (Group I showed highest values of resistance to push-out, both at all thirds as well as in total average (24.77 MPa, followed by light cure adhesive (Group II, 22.26 MPa, and dual cure (Group III, 18.38 MPa. Scothbond Multi-Purpose Plus – 3M adhesive system presented highest shear bond strength on resinous cementation of carbon posts to root dentin, and therefore is the first choice among the materials presented in this study.

  18. Synthesis and reactivity of compounds containing ruthenium-carbon, -nitrogen, and -oxygen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, J.F.

    1990-12-01

    The products and mechanisms of the thermal reactions of several complexes of the general structure (PMe{sub 3}){sub 4}Ru(X)(Y) and (DMPM){sub 2}Ru(X)(Y) where X and Y are hydride, aryl, and benzyl groups, have been investigated. The mechanism of decomposition depends critically on the structure of the complex and the medium in which the thermolysis is carried out. The alkyl hydride complexes are do not react with alkane solvent, but undergo C-H activation processes with aromatic solvents by several different mechanisms. Thermolysis of (PMe{sub 3}){sub 4}Ru(Ph)(Me) or (PMe{sub 3}){sub 4}Ru(Ph){sub 2} leads to the ruthenium benzyne complex (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{sub 4}) (1) by a mechanism which involves reversible dissociation of phosphine. In many ways its chemistry is analogous to that of early rather than late organo transition metal complexes. The synthesis, structure, variable temperature NMR spectroscopy and reactivity of ruthenium complexes containing aryloxide or arylamide ligands are reported. These complexes undergo cleavage of a P-C bond in coordinated trimethylphosphine, insertion of CO and CO{sub 2} and hydrogenolysis. Mechanistic studies on these reactions are described. The generation of a series of reactive ruthenium complexes of the general formula (PMe{sub 3}){sub 4}Ru(R)(enolate) is reported. Most of these enolates have been shown to bind to the ruthenium center through the oxygen atom. Two of the enolate complexes 8 and 9 exist in equilibrium between the O- and C-bound forms. The reactions of these compounds are reported, including reactions to form oxygen-containing metallacycles. The structure and reactivity of these ruthenium metallacycles is reported, including their thermal chemistry and reactivity toward protic acids, electrophiles, carbon monoxide, hydrogen and trimethylsilane. 243 refs., 10 tabs.

  19. Synthesis and reactivity of compounds containing ruthenium-carbon, -nitrogen, and -oxygen bonds

    International Nuclear Information System (INIS)

    The products and mechanisms of the thermal reactions of several complexes of the general structure (PMe3)4Ru(X)(Y) and (DMPM)2Ru(X)(Y) where X and Y are hydride, aryl, and benzyl groups, have been investigated. The mechanism of decomposition depends critically on the structure of the complex and the medium in which the thermolysis is carried out. The alkyl hydride complexes are do not react with alkane solvent, but undergo C-H activation processes with aromatic solvents by several different mechanisms. Thermolysis of (PMe3)4Ru(Ph)(Me) or (PMe3)4Ru(Ph)2 leads to the ruthenium benzyne complex (PMe3)4Ru(η2-C6H4) (1) by a mechanism which involves reversible dissociation of phosphine. In many ways its chemistry is analogous to that of early rather than late organo transition metal complexes. The synthesis, structure, variable temperature NMR spectroscopy and reactivity of ruthenium complexes containing aryloxide or arylamide ligands are reported. These complexes undergo cleavage of a P-C bond in coordinated trimethylphosphine, insertion of CO and CO2 and hydrogenolysis. Mechanistic studies on these reactions are described. The generation of a series of reactive ruthenium complexes of the general formula (PMe3)4Ru(R)(enolate) is reported. Most of these enolates have been shown to bind to the ruthenium center through the oxygen atom. Two of the enolate complexes 8 and 9 exist in equilibrium between the O- and C-bound forms. The reactions of these compounds are reported, including reactions to form oxygen-containing metallacycles. The structure and reactivity of these ruthenium metallacycles is reported, including their thermal chemistry and reactivity toward protic acids, electrophiles, carbon monoxide, hydrogen and trimethylsilane. 243 refs., 10 tabs

  20. Evaluation of the Effect of Silicone Contamination on Various Bond Systems and the Feasibility of Removing the Contamination

    Science.gov (United States)

    Stanley, Stephanie D.

    2008-01-01

    Silicone is a contaminant that can cause catastrophic failure of a bond system depending on the materials and processes used to fabricate the bond system, Unfortunately, more and more materials are fabricated using silicone. The purpose of this testing was to evaluate which bond systems are sensitive to silicone contamination and whether or not a cleaning process could be utilized to remove the silicone to bring the bond system performance back to baseline. Due to the extensive nature of the testing attempts will be made to generalize the understanding within classes of substrates, bond systems, and surface preparation and cleaning methods. This study was done by contaminating various meta! (steel, inconel, and aluminum), phenolic (carbon cloth phenolic and glass cloth phenolic), and rubber (natural rubber, asbestos-silicone dioxide filled natural butyldiene rubber, silica-filled ethylene propylenediene monomer, and carbon-filled ethylene propylenediene monomer) substrates which were then bonded using various adhesives and coatings (epoxy-based adhesives, paints, ablative compounds, and Chemlok adhesives) to determine the effect silicone contamination has on a given bond system's performance. The test configurations depended on the bond system being evaluated. The study also evaluated the feasibility of removing the silicone contamination by cleaning the contaminated substrate prior to bonding. The cleaning processes also varied depending on bond system.

  1. Surface chemistry of CO2 - Adsorption of carbon dioxide on clean surfaces at ultrahigh vacuum

    Science.gov (United States)

    Burghaus, Uwe

    2014-05-01

    Carbon dioxide chemistry has attracted significant interest in recent years. Although the field is diverse, a current and more comprehensive review of the surface science literature may be of interest for a variety of communities since environmental chemistry, energy technology, materials science, catalysis, and nanocatalysis are certainly affected by gas-surface properties. The review describes surface phenomena and characterization strategies highlighting similarities and differences, instead of providing only a list of system-specific information. The various systems are roughly distinguished as those that clearly form carbonates and those that merely physisorb CO2 at ultra-high vacuum conditions. Nevertheless, extended sections about specific systems including rarely studied surfaces and unusual materials are included, making this review also useful as a reference.

  2. PRECISION CLEANING OF SEMICONDUCTOR SURFACES USING CARBON DIOXIDE-BASED FLUIDS

    Energy Technology Data Exchange (ETDEWEB)

    J. RUBIN; L. SIVILS; A. BUSNAINA

    1999-07-01

    The Los Alamos National Laboratory, on behalf of the Hewlett-Packard Company, is conducting tests of a closed-loop CO{sub 2}-based supercritical fluid process, known as Supercritical CO{sub 2} Resist Remover (SCORR). We have shown that this treatment process is effective in removing hard-baked, ion-implanted photoresists, and appears to be fully compatible with metallization systems. We are now performing experiments on production wafers to assess not only photoresist removal, but also residual surface contamination due to particulate and trace metals. Dense-phase (liquid or supercritical) CO{sub 2}, since it is non-polar, acts like an organic solvent and therefore has an inherently high volubility for organic compounds such as oils and greases. Also, dense CO{sub 2} has a low-viscosity and a low dielectric constant. Finally, CO{sub 2} in the liquid and supercritical fluid states can solubilize metal completing agents and surfactants. This combination of properties has interesting implications for the removal not only of organic films, but also trace metals and inorganic particulate. In this paper we discuss the possibility of using CO{sub 2} as a precision-cleaning solvent, with particular emphasis on semiconductor surfaces.

  3. Assessment of clean-coal strategies: The questionable merits of carbon capture-readiness

    International Nuclear Information System (INIS)

    In this paper we investigate the value of capture-readiness by modeling the cost effectiveness of various alternative technological options and focusing on different clean-coal technology pathways. The modeling framework developed is based on stochastic net present value calculations. It allows for consideration of path-dependent and technology-specific risk combinations inherent in the input and output commodities that are relevant for operating the plant. We find that capture-readiness competes with alternative options of power plant replacements and that capture-readiness is not necessarily preferable from an economic perspective. - Highlights: ► An NPV model with technology- and path-dependent risk-adjusted discount rates is developed. ► The relative value of CCS retrofits compared to new power plants is examined. ► The projects, risk structure is important to consider while discounting cash flows. ► CCS retrofits are found to be less attractive compared to new-build power plants. ► The merit of capture-readiness is questionable due to competing other technologies

  4. Predicting mercury retention in utility gas cleaning systems with SCR/ESP/FGD combinations or activated carbon injection

    Energy Technology Data Exchange (ETDEWEB)

    Krishnakumar, Balaji; Naik, Chitralkumar V.; Niksa, Stephen [Niksa Energy Associates LLC, Belmont, CA (United States); Fujiwara, Naoki [Idemitsu Kosan Co., Ltd, Chiba (Japan). Coal and Environment Research Lab.

    2013-07-01

    This paper presents validations of the Hg speciation predicted by NEA's MercuRator trademark package with an American field test database for 28 full-scale utility gas cleaning systems. It emphasizes SCR/ESP/FGD combinations and activated carbon injection because these two applications present the best long- term prospects for Hg control by coal-burning utilities. Validations of the extents of Hg{sup 0} oxidation across SCRs and of Hg retention in wet FGDs gave correlation coefficients greater than 0.9 for both units. A transport-based FGD analysis correctly assessed the potential for Hg{sup 0} re-emission in one limestone wet FGD. Among the ten stations in the SCR/ESP/FGD validations, the simulations correctly identified 3 of 4 of the relatively high Hg emissions rates; all four of the sites with moderate emissions rates; and both sites with the lowest emission rates. The validations for ACI applications demonstrated that Hg removals can be accurately estimated for the full domain of coal quality, LOI, and ACI rates for both untreated and brominated carbon sorbents. The predictions for ACI depict the test-to-test variations in most cases, and accurately describe the impact of ACI configuration and sorbent type. ACI into FFs is the most effective configuration, although ACI into ESPs often removes 90% or more Hg, provided that there is sufficient residence time and Cl in the flue gas. Brominated sorbents perform better than untreated carbons, unless SO{sub 3} condensation inhibits Hg adsorption.

  5. A Study of Bond of Structural Timber and Carbon Fiber Reinforced Polymer Plate

    Directory of Open Access Journals (Sweden)

    Yongtaeg LEE

    2015-11-01

    Full Text Available The increase of well-being culture of problem related to environmental depletion of resource is not the growing interest in timber the natural material of construction markets. Also, the perception for historic preservation has been increased in respond to heightened interest. However, it is fairly difficult for architectural properties to maintain their durability because it was made by timber construction. Preventing traditional structure from damage and structural performance reduction is paramount in maintenance problem. A number of studies of reinforced method have been conducted in order to solve such a problem. In this paper, external bonded reinforcement and near-surface mounted was used as a way to reinforce timber structure’s durability. Bond strength for specimens with different bond length was investigated. As a result showed, maximum bond strength in bond length 300 mm from all method, was found to be not increased of bond strength over the certain bond length.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9702

  6. Supercritical carbon dioxide (SC-CO2) as a clean technology for palm kernel oil extraction

    OpenAIRE

    Norhuda I; Jusoff K

    2009-01-01

    Efforts towards application of Supercritical Carbon Dioxide (SCCO2) extraction in Malaysia are still at its infancy stage. More research has actively on-going to explore its potential performance on a bigger scale (industrial scale) so that it will provide a better alternative method of extraction compare to the present practice using organic solvent extraction. SC-CO2 has been proven on laboratory and pilot-scale as an effective extraction technique for large types of bio-materials such as h...

  7. Asynchronous through-bond homonuclear isotropic mixing: application to carbon–carbon transfer in perdeuterated proteins under MAS

    Energy Technology Data Exchange (ETDEWEB)

    Kulminskaya, Natalia; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus, E-mail: rali@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)

    2015-11-15

    Multiple-bond carbon–carbon homonuclear mixing is a hurdle in extensively deuterated proteins and under fast MAS due to the absence of an effective proton dipolar-coupling network. Such conditions are now commonly employed in solid-state NMR spectroscopy. Here, we introduce an isotropic homonuclear {sup 13}C–{sup 13}C through-bond mixing sequence, MOCCA, for the solid state. Even though applied under MAS, this scheme performs without rotor synchronization and thus does not pose the usual hurdles in terms of power dissipation for fast spinning. We compare its performance with existing homonuclear {sup 13}C–{sup 13}C mixing schemes using a perdeuterated and partially proton-backexchanged protein. Based on the analysis of side chain carbon–carbon correlations, we show that particularly MOCCA with standard 180-degree pulses and delays leading to non-rotor-synchronized spacing performs exceptionally well. This method provides high magnetization transfer efficiency for multiple-bond transfer in the aliphatic region compared with other tested mixing sequences. In addition, we show that this sequence can also be tailor-made for recoupling within a selected spectral region using band-selective pulses.

  8. Asynchronous through-bond homonuclear isotropic mixing: application to carbon–carbon transfer in perdeuterated proteins under MAS

    International Nuclear Information System (INIS)

    Multiple-bond carbon–carbon homonuclear mixing is a hurdle in extensively deuterated proteins and under fast MAS due to the absence of an effective proton dipolar-coupling network. Such conditions are now commonly employed in solid-state NMR spectroscopy. Here, we introduce an isotropic homonuclear 13C–13C through-bond mixing sequence, MOCCA, for the solid state. Even though applied under MAS, this scheme performs without rotor synchronization and thus does not pose the usual hurdles in terms of power dissipation for fast spinning. We compare its performance with existing homonuclear 13C–13C mixing schemes using a perdeuterated and partially proton-backexchanged protein. Based on the analysis of side chain carbon–carbon correlations, we show that particularly MOCCA with standard 180-degree pulses and delays leading to non-rotor-synchronized spacing performs exceptionally well. This method provides high magnetization transfer efficiency for multiple-bond transfer in the aliphatic region compared with other tested mixing sequences. In addition, we show that this sequence can also be tailor-made for recoupling within a selected spectral region using band-selective pulses

  9. Cleaning efficiency of carbon films by oxygen plasmas in the presence of metallic getters

    Energy Technology Data Exchange (ETDEWEB)

    Tabares, F L; Ferreira, J A; Tafalla, D [Laboratorio Nacional de Fusion, As. Euratom/Ciemat.Madrid (Spain); Tanarro, I; Herrero, V J; Mendez, I [Instituto de Estructura de la Materia, CSIC, Madrid (Spain); Gomez-Aleixandre, C; Albella, J M [Instituto de Ciencia de Materiales, CSIC. Madrid (Spain)], E-mail: tabares@ciemat.es

    2008-03-15

    In the present work, the effect that strong metallic getters has in the carbon removal rate by He/O{sub 2} glow discharges is addressed. Due to the stringent conditions required for the use of Be in laboratory experiments, Li and Mg have been tested as O getters, the former showing also high H-getter properties. Samples of C/Metal mixtures are produced by introducing the metallic evaporator into the glow discharge deposition chamber, which is kept at room temperature. Two schemes were used: layered deposition and full mix-up. Hydrogen methane mixtures are used as precursors of hard a-C: H films in a DC glow discharge apparatus. The film growth and removal rate was monitored in situ through laser interferometry and particle balance from the mass spectrometer data. Surface analysis techniques have been applied for the mixed film characterization prior and after the exposure to the oxidizing plasma. Removal rates up to 12 nm/min are obtained in the absence of metals. It was found that full removal of carbon from the metal/C layers was possible for the plasma conditions used. Rates of similar value to those of pure C films were achieved except for the case of layered deposition, where a decrease in the film etching rate was observed corresponding to the location of the metal layer.

  10. Analysis of the number of hydrogen bond groups of a multiwalled carbon nanotube probe tip for chemical force microscopy

    International Nuclear Information System (INIS)

    In this paper, we describe a statistical method of quantification of the number of functional groups at the contact area of a probe tip for atomic force microscopy from the result of repetitive pull-off force measurements. We have investigated laboratory-made carbon nanotube (CNT) probe tips to apply them for chemical force microscopy because limited number of functional groups at the tip-end is expected. Using a CNT tip, we conducted repetitive pull-off force measurements against a self-assembled monolayer terminated with carboxyl group and analyzed them in terms of the number of hydrogen bond groups at the CNT tip. The elementary hydrogen bond rupture force quantum in n-decane medium was estimated to be 84.2 ± 0.5 pN in the present system. Thus it was revealed that only a couple of hydrogen bond groups of the CNT tip were participating in hydrogen bonding with the sample on an average in this experimental system.

  11. Optimized composition for bonding assistant coat in carbon steel sandwich panels

    Institute of Scientific and Technical Information of China (English)

    Jing Liu; Jingtao Han

    2007-01-01

    On the basis of the alloying theory of bonding assistant coat (BAC),taking into account of the interaction of alloy elements,the regressive equation,which relates the wetting ability of bonding assistant coat with the contents of Mn,Ni,Si,Sn,and B,was established by using quadratic regression orthogonal design of five factors.The influence of elements and their interaction on the wetting ability was analyzed.The ranges of alloy elements were optimized.The melting point of bonding assistant coat was measured by using differential thermal analysis.The results show that the interactions of Ni and Mn,Ni,and Sn can increase the wetting ability obviously and the melting point of bonding assistant coat has been decreased.

  12. ELECTROCHEMICAL STUDIES ON THE CORROSION OF CARBON STEEL IN OXALIC ACID CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; John Mickalonis, J

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS has utilized oxalic acid to accomplish this task. Since the waste tanks are constructed of carbon steel, a significant amount of corrosion may occur. Although the total amount of corrosion may be insignificant for a short contact time, a significant amount of hydrogen may be generated due to the corrosion reaction. Linear polarization resistance and anodic/cathodic polarization tests were performed to investigate the corrosion behavior during the process. The effect of process variables such as temperature, agitation, aeration, sample orientation, light as well as surface finish on the corrosion behavior were evaluated. The results of the tests provided insight into the corrosion mechanism for the iron-oxalic acid system.

  13. Polyaniline-Coated Carbon Nanotube Ultrafiltration Membranes: Enhanced Anodic Stability for In Situ Cleaning and Electro-Oxidation Processes.

    Science.gov (United States)

    Duan, Wenyan; Ronen, Avner; Walker, Sharon; Jassby, David

    2016-08-31

    Electrically conducting membranes (ECMs) have been reported to be efficient in fouling prevention and destruction of aqueous chemical compounds. In the current study, highly conductive and anodically stable composite polyaniline-carbon nanotube (PANI-CNT) ultrafiltration (UF) ECMs were fabricated through a process of electropolymerization of aniline on a CNT substrate under acidic conditions. The resulting PANI-CNT UF ECMs were characterized by scanning electron microscopy, atomic force microscopy, a four-point conductivity probe, cyclic voltammetry, and contact angle goniometry. The utilization of the PANI-CNT material led to significant advantages, including: (1) increased electrical conductivity by nearly an order of magnitude; (2) increased surface hydrophilicity while not impacting membrane selectivity or permeability; and (3) greatly improved stability under anodic conditions. The membrane's anodic stability was evaluated in a pH-controlled aqueous environment under a wide range of anodic potentials using a three-electrode cell. Results indicate a significantly reduced degradation rate in comparison to a CNT-poly(vinyl alcohol) ECM under high anodic potentials. Fouling experiments conducted with bovine serum albumin demonstrated the capacity of the PANI-CNT ECMs for in situ oxidative cleaning, with membrane flux restored to its initial value under an applied potential of 3 V. Additionally, a model organic compound (methylene blue) was electrochemically transformed at high efficiency (90%) in a single pass through the anodically charged ECM. PMID:27525344

  14. Surgical scrubbing: can we clean up our carbon footprints by washing our hands?

    Science.gov (United States)

    Somner, J E A; Stone, N; Koukkoulli, A; Scott, K M; Field, A R; Zygmunt, J

    2008-11-01

    A growing scientific consensus states that the global climate is changing and that human activity is responsible for these changes. It folLows that each of us has a responsibility to look at how our own lives impact on the environment. This study aimed to investigate water use during surgical scrubbing. Two water delivery systems were assessed to see whether technological innovation can promote more 'environmentally friendly' scrubbing behaviour. At least 10 different individuals, comprising surgeons, assistants and scrub nurses, were observed at two sites. Twenty-five separate surgical scrubs were observed in each location and the length of time for which the tap was on recorded. The tap was on during surgical scrubbing for a mean of 2 min 23 s at Gartnavel General Hospital (maximum: 4 min 37 s; minimum: 49 s; SD: 55 s) and for a mean of 1 min 7 s at Stobhill Hospital (maximum: 2 min 25 s; minimum: 19 s; SD: 33 s). The mean 'tap on' time (in seconds) at Gartnavel was significantly greater than that at Stobhill [t(39.5)=Pscrub. Surgical scrubbing is a ubiquitous procedure performed daily in healthcare settings. A simple technological solution can reduce water and energy use by modifying hand-washing behaviour and thereby reduce the carbon footprint of surgical scrubbing. PMID:18701193

  15. Penetration of tritium (as tritiated water vapour) into low carbon steel and remediation using abrasive cleaning

    International Nuclear Information System (INIS)

    The UKAEA Winfrith site is in a phase of accelerated decommissioning and de-licensing which will generate significant volumes of metal wastes some of which may be suitable for disposal as exempt wastes. If contamination is present, it is often confined within the surface layers of the metal. The UKAEA Winfrith site operates a shot-blast facility (WACM) that removes paint and surface contamination from low carbon steel enabling surface contaminated painted metal to be processed and therefore certified as exempt. A study was conducted to determine whether tritium (as tritiated water vapour) has penetrated into the metal to levels exceeding the Radioactive Substances Act (1993), Substances of Low Activity (SoLA) Exemption Order criteria, and whether processing via the WACM removes sufficient tritium contamination that the SoLA Exemption Order criteria can be met. The results of sampling and analysis show that the tritium is mainly held in the paint or outer 40 μm layer of the metal and that processing through the WACM removes these layers along with sufficient tritium to meet the SoLA Exemption Order criteria

  16. Conservation and Functional Importance of Carbon-Oxygen Hydrogen Bonding in AdoMet-Dependent Methyltransferases

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Scott; Dirk, Lynnette M.A.; Yesselman, Joseph D.; Nimtz, Jennifer S.; Adhikari, Upendra; Mehl, Ryan A.; Scheiner, Steve; Houtz, Robert L.; Al-Hashimi, Hashim M.; Trievel, Raymond C. [Oregon State U.; (Michigan); (Utah SU); (HHMI); (Kentucky)

    2013-09-06

    S-Adenosylmethionine (AdoMet)-based methylation is integral to metabolism and signaling. AdoMet-dependent methyltransferases belong to multiple distinct classes and share a catalytic mechanism that arose through convergent evolution; however, fundamental determinants underlying this shared methyl transfer mechanism remain undefined. A survey of high-resolution crystal structures reveals that unconventional carbon–oxygen (CH···O) hydrogen bonds coordinate the AdoMet methyl group in different methyltransferases irrespective of their class, active site structure, or cofactor binding conformation. Corroborating these observations, quantum chemistry calculations demonstrate that these charged interactions formed by the AdoMet sulfonium cation are stronger than typical CH···O hydrogen bonds. Biochemical and structural studies using a model lysine methyltransferase and an active site mutant that abolishes CH···O hydrogen bonding to AdoMet illustrate that these interactions are important for high-affinity AdoMet binding and transition-state stabilization. Further, crystallographic and NMR dynamics experiments of the wild-type enzyme demonstrate that the CH···O hydrogen bonds constrain the motion of the AdoMet methyl group, potentially facilitating its alignment during catalysis. Collectively, the experimental findings with the model methyltransferase and structural survey imply that methyl CH···O hydrogen bonding represents a convergent evolutionary feature of AdoMet-dependent methyltransferases, mediating a universal mechanism for methyl transfer.

  17. Metabolic Engineering to Develop a Pathway for the Selective Cleavage of Carbon-Nitrogen Bonds

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2005-10-01

    The objective of the project is to develop a biochemical pathway for the selective cleavage of C-N bonds in molecules found in petroleum. Specifically a novel biochemical pathway will be developed for the selective cleavage of C-N bonds in carbazole. The cleavage of the first C-N bond in carbazole is accomplished by the enzyme carbazole dioxygenase, that catalyzes the conversion of carbazole to 2-aminobiphenyl-2,3-diol. The genes encoding carbazole dioxygenase were cloned from Sphingomonas sp. GTIN11 and from Pseudomonas resinovorans CA10. The selective cleavage of the second C-N bond has been challenging, and efforts to overcome that challenge have been the focus of recent research in this project. Enrichment culture experiments succeeded in isolating bacterial cultures that can metabolize 2-aminobiphenyl, but no enzyme capable of selectively cleaving the C-N bond in 2-aminobiphenyl has been identified. Aniline is very similar to the structure of 2-aminobiphenyl and aniline dioxygenase catalyzes the conversion of aniline to catechol and ammonia. For the remainder of the project the emphasis of research will be to simultaneously express the genes for carbazole dioxygenase and for aniline dioxygenase in the same bacterial host and then to select for derivative cultures capable of using carbazole as the sole source of nitrogen.

  18. Supersonic Retropulsion Surface Preparation of Carbon Fiber Reinforced Epoxy Composites for Adhesive Bonding

    Science.gov (United States)

    Palmieri, Frank L.; Belcher, Marcus A.; Wohl, Christopher J.; Blohowiak, Kay Y.; Connell, John W.

    2013-01-01

    Surface preparation is widely recognized as a key step to producing robust and predictable bonds in a precise and reproducible manner. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, can lack precision and reproducibility, which can lead to variation in surface properties and subsequent bonding performance. The use of a laser to ablate composite surface resin can provide an efficient, precise, and reproducible means of preparing composite surfaces for adhesive bonding. Advantages include elimination of physical waste (i.e., grit media and sacrificial peel ply layers that ultimately require disposal), reduction in process variability due to increased precision (e.g. increased reproducibility), and automation of surface preparation, all of which improve reliability and process control. This paper describes a Nd:YAG laser surface preparation technique for composite substrates and the mechanical performance and failure modes of bonded laminates thus prepared. Additionally, bonded specimens were aged in a hot, wet environment for approximately one year and subsequently mechanically tested. The results of a one year hygrothermal aging study will be presented.

  19. Intrinsic carrier mobility of a single-layer graphene covalently bonded with single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    We report intrinsic carrier mobility calculations of a two-dimensional nanostructure that consists of porous single layer graphene covalently bonded with single-walled carbon nanotubes on both sides. We used first-principles calculation and found that the deformation potential of such system is about 25% of that of graphene, and the carrier mobility is about 5 × 104 cm2 V−1 s−1 for both electrons and holes, about one order of magnitude lower than that of graphene. This nanostructure and its three-dimensional stacking could serve as novel organic electronic materials.

  20. Hydrogen passivation effects on carbon dangling bond defects accompanying a nearby hydrogen atom in p-type Cd diamond

    Energy Technology Data Exchange (ETDEWEB)

    Mizuochi, N. [Graduate School of Library, Information and Media Studies, University of Tsukuba, 1-2 Kasuga, Tsukuba-City, Ibaraki 305-8550 (Japan) and Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan) and CREST JST - Japan Science and Technology (Japan)]. E-mail: mizuochi@slis.tsukuba.ac.jp; Ogura, M. [Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); CREST JST (Japan Science and Technology) (Japan); Isoya, J. [Graduate School of Library, Information and Media Studies, University of Tsukuba, 1-2 Kasuga, Tsukuba-City, Ibaraki 305-8550 (Japan); Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Okushi, H. [Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); CREST JST (Japan Science and Technology) (Japan); Yamasaki, S. [Diamond Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); CREST JST (Japan Science and Technology) (Japan); Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8577 (Japan)

    2006-04-01

    Hydrogen (deuterium) passivation effects on carbon dangling bond defects accompanying a nearby hydrogen atom (H1') in boron-doped Cd homoepitaxial diamond films were investigated by electron paramagnetic resonance (EPR). Deuterium was incorporated into the films using microwave deuterium plasma at 673 K for 22 h. Incorporation of deuterium was confirmed by the passivation of boron acceptors. From the comparison of the EPR signal intensity before and after the deuterium plasma exposure, it was revealed that H1' could not be passivated by the present condition. From these, the high stability of H1' was indicated.

  1. Hard three-dimensional sp2 carbon-bonded phase formed by ion beam irradiation of fullerene, a-C and polymeric a-C:H films

    International Nuclear Information System (INIS)

    The formation of new carbon amorphous phase through the ion irradiation of fullerene, a-C and polymeric a-C:H films is presented. The carbon films were subjected to N irradiation at 400 keV in the fluence range from 1013 to 3 x 1016 N cm-2. Modifications in the carbon structure, as function of the irradiation fluence, were investigated using the Rutherford backscattering spectrometry, nuclear reaction analysis, Fourier transform infrared, Raman spectroscopy, UV-VIS-NearIR spectrophotometry and nanoindentation techniques. After high fluence, the three carbon samples were transformed into very similar hard (∼14 GPa) and non-hydrogenated amorphous carbon layers with very low optical gaps (∼0.2 eV) and an unusual sp2 rich-bonded atomic network. The mechanical properties of the irradiated films correlated with the bonding topologies of this new sp2 carbon phase are analyzed in terms of the constraint-counting model. The results show that the unusual rigidity was achieved by the distortion of the sp2 carbon bond angles, giving origin to a constrained three-dimensional sp2 carbon bonded network

  2. Effect of bonding time on joint properties of vacuum brazed WC - Co hard metal/carbon steel using stacked Cu and Ni alloy as insert metal

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.B.; Jung, S.B. [Sungkyunkwan Univ., Dept. of Advanced Materials Engineering, Suwon, Kyounggi-do (Korea); Kwon, B.D. [Seoul Technical High School, Dept. of Metallurgy, Seoul (Korea)

    2004-11-15

    Hard metal WC - Co and carbon steel were successfully joined using double layered Cu alloy and amorphous Ni alloy as inert metal and an oil cooling method after brazing. Defects such as cracks and voids were not formed near the bonded zone. This result means that double layered insert metals and oil cooling minimised the residual stress near the bonded zone after brazing. The shear strength of the joints decreased with increasing bond time. The reasons why the shear strength decreased as bond time increased could be many, including shape of the interface, formation and growth of brittle intermetallic compounds, and coarsening of WC particles near the bond zone. The maximum shear strength of the joints was 310 MPa under conditions 0.6 ks bond time and 8 wt-%Co content in the WC hard alloy. (Author)

  3. Building carbon–carbon bonds using a biocatalytic methanol condensation cycle

    OpenAIRE

    Bogorad, Igor W.; Chen, Chang-Ting; Theisen, Matthew K.; Wu, Tung-Yun; Schlenz, Alicia R.; Lam, Albert T.; Liao, James C.

    2014-01-01

    With the recent discoveries of large reserves of natural gas, the efficient utilization of one-carbon compounds for chemical synthesis would reduce the raw material cost for the petroleum-based chemical industry. Methanol is produced industrially from methane and is a feedstock chemical for the synthesis of higher carbon compounds. However, current chemical synthesis of higher carbon compounds from methanol requires high temperature and pressure. Natural biological pathways for methanol utili...

  4. Enhanced dispersion stability and mobility of carboxyl-functionalized carbon nanotubes in aqueous solutions through strong hydrogen bonds

    International Nuclear Information System (INIS)

    Dispersion of carbon nanotubes has been heavily studied due to its importance for their technical applications, toxic effects, and environmental impacts. Common electrolytes, such as sodium chloride and potassium chloride, promote agglomeration of nanoparticles in aqueous solutions. On the contrary, we discovered that acetic electrolytes enhanced the dispersion of multi-walled carbon nanotubes (MWCNTs) with carboxyl functional group through the strong hydrogen bond, which was confirmed by UV–Vis spectrometry, dispersion observations and aerosolization-quantification method. When concentrations of acetate electrolytes such as ammonium acetate (CH3CO2NH4) and sodium acetate (CH3CO2Na) were lower than 0.03 mol per liter, MWCNT suspensions showed better dispersion and had higher mobility in porous media. The effects by the acetic environment are also applicable to other nanoparticles with the carboxyl functional group, which was demonstrated with polystyrene latex particles as an example

  5. Enhanced dispersion stability and mobility of carboxyl-functionalized carbon nanotubes in aqueous solutions through strong hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Yeon Kyoung; He, Xu; Gitsis, Emmanouil; Kuo, Yu-Ying [ETH Zurich, Institute of Environmental Engineering (Switzerland); Kim, Nayoung [EMPA, Building Energy Materials and Components (Switzerland); Wang, Jing, E-mail: jing.wang@ifu.baug.ethz.ch [ETH Zurich, Institute of Environmental Engineering (Switzerland)

    2015-10-15

    Dispersion of carbon nanotubes has been heavily studied due to its importance for their technical applications, toxic effects, and environmental impacts. Common electrolytes, such as sodium chloride and potassium chloride, promote agglomeration of nanoparticles in aqueous solutions. On the contrary, we discovered that acetic electrolytes enhanced the dispersion of multi-walled carbon nanotubes (MWCNTs) with carboxyl functional group through the strong hydrogen bond, which was confirmed by UV–Vis spectrometry, dispersion observations and aerosolization-quantification method. When concentrations of acetate electrolytes such as ammonium acetate (CH{sub 3}CO{sub 2}NH{sub 4}) and sodium acetate (CH{sub 3}CO{sub 2}Na) were lower than 0.03 mol per liter, MWCNT suspensions showed better dispersion and had higher mobility in porous media. The effects by the acetic environment are also applicable to other nanoparticles with the carboxyl functional group, which was demonstrated with polystyrene latex particles as an example.

  6. Optimal energy options under Clean Development Mechanism: Renewable energy projects for sustainable development and carbon emission reduction

    Science.gov (United States)

    Gilau, Asmerom M.

    This dissertation addresses two distinct objectives; designing cost-effective renewable energy powered projects including seawater reverse osmosis (SWRO), aquaculture, and ice-making plant, and analyzing the cost-effectiveness of these projects in achieving low abatement costs and promoting sustainable developments under the Clean Development Mechanism. The results of SWRO analysis show that a wind powered system is the least expensive and a PV powered system the most expensive, with finished water costs of about 0.50 /m3 and 1.00 /m3, respectively. By international standards, these costs are competitive. The results of renewable energy powered commercial tilapia production indicate that a wind-diesel system has high potential for intensive tilapia production as well as carbon dioxide emission reductions. The study also investigates aeration failures in renewable energy powered tilapia production systems. With respect to the ice-making plant, unlike previous studies which consider nighttime operation only, we have found that a nighttime PV powered ice-making system is more expensive (1/kWh) than daytime ice-making system (0.70/kWh). Our optimal energy options analysis at project scale which includes SWRO, ice-making plant and household energy consumption for about 100 households shows that compared to diesel only energy option, PV-D, W-D, and PV-W-D hybrids are very cost-effective energy options. Moreover, energy options with high levels of renewable energy including 100% renewables have the lowest net present cost and they are already cost-effective without CDM. On the other hand, while the removal of about 87% carbon dioxide emissions could be achieved at negative cost, initial investment could increase by a factor of 40, which is one of the primary barriers hindering wider renewable energy applications in developing countries. Thus in order to increase developing countries' participation in the carbon market, CDM policy should shift from a purely market oriented

  7. METABOLIC ENGINEERING TO DEVELOP A PATHWAY FOR THE SELECTIVE CLEAVAGE OF CARBON-NITROGEN BONDS

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2004-10-01

    The objective of the project is to develop biochemical pathways for the selective cleavage of C-N bonds in molecules found in petroleum. The initial phase of the project was focused on the isolation or development of an enzyme capable of cleaving the C-N bond in aromatic amides, specifically 2-aminobiphenyl. The objective of the second phase of the research will be to construct a biochemical pathway for the selective removal of nitrogen from carbazole by combining the carA genes from Sphingomonas sp. GTIN11 with the gene(s) encoding an appropriate deaminase. The objective of the final phase of the project will be to develop derivative C-N bond cleaving enzymes that have broader substrate ranges and to demonstrate the use of such strains to selectively remove nitrogen from petroleum. During the first year of the project (October, 2002-September, 2003) enrichment culture experiments resulted in the isolation of microbial cultures that utilize aromatic amides as sole nitrogen sources, several amidase genes were cloned and were included in directed evolution experiments to obtain derivatives that can cleave C-N bonds in aromatic amides, and the carA genes from Sphingomonas sp. GTIN11, and Pseudomonas resinovorans CA10 were cloned in vectors capable of replicating in Escherichia coli. During the second year of the project (October, 2003-September, 2004) enrichment culture experiments succeeded in isolating a mixed bacterial culture that can utilize 2-aminobiphenyl as a sole nitrogen source, directed evolution experiments were focused on the aniline dioxygenase enzyme that is capable of deaminating aniline, and expression vectors were constructed to enable the expression of genes encoding C-N bond cleaving enzymes in Rhodococcus hosts. The construction of a new metabolic pathway to selectively remove nitrogen from carbazole and other molecules typically found in petroleum should lead to the development of a process to improve oil refinery efficiency by reducing the

  8. Improving Bond Strenght between Carbon Steel and Plasma Sprayed Ceramics by Phosphating Process

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Brožek, Vlastimil; Mastný, L.

    Ostrava : TANGER Ltd. Ostrava, 2012, s. 69-70. ISBN 978-80-87294-31-4. [International Conference on Metallurgy and Materials METAL 2012/21./. Brno (CZ), 23.05.2012-25.05.2012] Institutional research plan: CEZ:AV0Z20430508 Keywords : surface treatments * phosphating coatings * bond strenght * plasma spraying * ceramic coatings Subject RIV: CA - Inorganic Chemistry

  9. METABOLIC ENGINEERING TO DEVELOP A PATHWAY FOR THE SELECTIVE CLEAVAGE OF CARBON-NITROGEN BONDS

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane III

    2003-12-01

    The objective of the project is to develop biochemical pathways for the selective cleavage of C-N bonds in molecules found in petroleum. The initial phase of the project will focus on the isolation or development of an enzyme capable of cleaving the C-N bond in aromatic amides, specifically 2-aminobiphenyl. The objective of the second phase of the research will be to construct a biochemical pathway for the selective removal of nitrogen from carbazole by combining the carA genes from Sphingomonas sp. GTIN11 with the gene(s) encoding an appropriate amidase. The objective of the final phase of the project will be to develop derivative CN bond cleaving enzymes that have broader substrate ranges and to demonstrate the use of such strains to selectively remove nitrogen from petroleum. The project is on schedule and no major difficulties have been encountered. During the first year of the project (October, 2002-September, 2003) enrichment culture experiments have resulted in the isolation of promising cultures that may be capable of cleaving C-N bonds in aromatic amides, several amidase genes have been cloned and are currently undergoing directed evolution to obtain derivatives that can cleave C-N bonds in aromatic amides, and the carA genes from Sphingomonas sp. GTIN11, and Pseudomonas resinovorans CA10 were cloned in vectors capable of replicating in Escherichia coli. Future research will address expression of these genes in Rhodococcus erythropolis. Enrichment culture experiments and directed evolution experiments continue to be a main focus of research activity and further work is required to obtain an appropriate amidase that will selectively cleave C-N bonds in aromatic substrates. Once an appropriate amidase gene is obtained it must be combined with genes encoding an enzyme capable of converting carbazole to 2'aminobiphenyl-2,3-diol: specifically carA genes. The carA genes from two sources have been cloned and are ready for construction of C-N bond cleavage

  10. Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yanmei, Jin, E-mail: jinyanmei818@163.com [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China); Haihui, Liu; Ning, Wang; Lichen, Hou [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China); Xing-Xiang, Zhang, E-mail: zhangpolyu@gmail.com [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China)

    2012-08-15

    A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT-COOH) > hydroxyl MWNTs (MWNT-OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT-COOH and PEEK, MWNT-OH and PEEK, and possible formation of a chemical bond between MWNT-COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT-COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa. -- Highlights: Black-Right-Pointing-Pointer Functional groups on MWNTs improve their hydrophobility and dispersability. Black-Right-Pointing-Pointer Mechanical properties depend on the content and species of the functional groups. Black-Right-Pointing-Pointer The reinforced effect is in the sequence, carboxylic MWNTs > hydroxyl MWNTs > MWNTs. Black-Right-Pointing-Pointer The strength behavior was result of hydrogen bond, affinity and chemical bond. Black-Right-Pointing-Pointer Dispersability of MWNTs in matrix was analyzed by

  11. Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

    International Nuclear Information System (INIS)

    A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT–COOH) > hydroxyl MWNTs (MWNT–OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT–COOH and PEEK, MWNT–OH and PEEK, and possible formation of a chemical bond between MWNT–COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT–COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa. -- Highlights: ► Functional groups on MWNTs improve their hydrophobility and dispersability. ► Mechanical properties depend on the content and species of the functional groups. ► The reinforced effect is in the sequence, carboxylic MWNTs > hydroxyl MWNTs > MWNTs. ► The strength behavior was result of hydrogen bond, affinity and chemical bond. ► Dispersability of MWNTs in matrix was analyzed by calculating solubility parameter.

  12. Carbon monoxide protonation in condensed phases and bonding to surface superacidic Brønsted centers.

    Science.gov (United States)

    Stoyanov, Evgenii S; Malykhin, Sergei E

    2016-02-14

    Using infrared (IR) spectroscopy and density functional theory (DFT) calculations, interaction of CO with the strongest known pure Brønsted carborane superacids, H(CHB11Hal11) (Hal = F, Cl), was studied. CO readily interacted at room temperature with H(CHB11F11) acid, forming a mixture of bulk salts of formyl and isoformyl cations, which were in equilibrium An(-)H(+)CO COH(+)An(-). The bonding of CO to the surface Brønsted centers of the weaker acid, H(CHB11Cl11), resulted in breaking of the bridged H-bonds of the acid polymers without proton transfer (PT) to CO. The binding occurred via the C atom (blue shift ΔνCO up to +155-167 cm(-1), without PT) or via O atom (red shift ΔνCO up to -110 cm(-1), without PT) always simultaneously, regardless of whether H(+) is transferred to CO. IR spectra of all species were interpreted by B3LYP/cc-pVQZ calculations of the simple models, which adequately mimic the ability of carborane acids to form LH(+)CO, LH(+)CO, COH(+)L, and COH(+)L compounds (L = bases). The CO bond in all compounds was triple. Acidic strength of the Brønsted centers of commonly used acid catalysts, even so-called superacidic catalysts, is not sufficient for the formation of the compounds studied. PMID:26805010

  13. Velocity Map Imaging Study of Ion-Radical Chemistry: Charge Transfer and Carbon-Carbon Bond Formation in the Reactions of Allyl Radicals with C(.).

    Science.gov (United States)

    Pei, Linsen; Farrar, James M

    2016-08-11

    We present an experimental and computational study of the dynamics of collisions of ground state carbon cations with allyl radicals, C3H5, at a collision energy of 2.2 eV. Charge transfer to produce the allyl cation, C3H5(+), is exoergic by 3.08 eV and proceeds via energy resonance such that the electron transfer occurs without a significant change in nuclear velocities. The products have sufficient energy to undergo the dissociation process C3H5(+) → C3H4(+) + H. Approximately 80% of the reaction products are ascribed to charge transfer, with ∼40% of those products decaying via loss of a hydrogen atom. We also observe products arising from the formation of new carbon-carbon bonds. The experimental velocity space flux distributions for the four-carbon products are symmetric about the centroid of the reactants, providing direct evidence that the products are mediated by formation of a C4H5(+) complex living at least a few rotational periods. The primary four-carbon reaction products are formed by elimination of molecular hydrogen from the C4H5(+) complex. More than 75% of the nascent C4H3(+) products decay by C-H bond cleavage to yield a C4H2(+) species. Quantum chemical calculations at the MP2/6-311+g(d,p) level of theory support the formation of a nonplanar cyclic C4H5(+) adduct that is produced when the p-orbital containing the unpaired electron on C(+) overlaps with the unpaired spin density on the terminal carbon atoms in allyl. Product formation then occurs by 1,2-elimination of molecular hydrogen from the cyclic intermediate to form a planar cyclic C4H3(+) product. The large rearrangement in geometry as the C4H3(+) products are formed is consistent with high vibrational excitation in that product and supports the observation that the majority of those products decay to form the C4H2(+) species. PMID:27434380

  14. Adsorption, desorption, and film formation of quinacridone and its thermal cracking product indigo on clean and carbon-covered silicon dioxide surfaces.

    Science.gov (United States)

    Scherwitzl, Boris; Lassnig, Roman; Truger, Magdalena; Resel, Roland; Leising, Günther; Winkler, Adolf

    2016-09-01

    The evaporation of quinacridone from a stainless steel Knudsen cell leads to the partial decomposition of this molecule in the cell, due to its comparably high sublimation temperature. At least one additional type of molecules, namely indigo, could be detected in the effusion flux. Thermal desorption spectroscopy and atomic force microscopy have been used to study the co-deposition of these molecules on sputter-cleaned and carbon-covered silicon dioxide surfaces. Desorption of indigo appears at temperatures of about 400 K, while quinacridone desorbs at around 510 K. For quinacridone, a desorption energy of 2.1 eV and a frequency factor for desorption of 1 × 10(19) s(-1) were calculated, which in this magnitude is typical for large organic molecules. A fraction of the adsorbed quinacridone molecules (∼5%) decomposes during heating, nearly independent of the adsorbed amount, resulting in a surface composed of small carbon islands. The sticking coefficients of indigo and quinacridone were found to be close to unity on a carbon covered SiO2 surface but significantly smaller on a sputter-cleaned substrate. The reason for the latter can be attributed to insufficient energy dissipation for unfavorably oriented impinging molecules. However, due to adsorption via a hot-precursor state, the sticking probability is increased on the surface covered with carbon islands, which act as accommodation centers. PMID:27609005

  15. Multiplug filtration clean-up with multiwalled carbon nanotubes in the analysis of pesticide residues using LC-ESI-MS/MS.

    Science.gov (United States)

    Zhao, Pengyue; Fan, Sufang; Yu, Chuanshan; Zhang, Junyan; Pan, Canping

    2013-10-01

    A novel design for a rapid clean-up method was developed for the analysis of pesticide residues in fruit and vegetables followed by LC-ESI-MS/MS. The acetonitrile-based sample extraction technique was used to obtain the extracts, and further clean-up was carried out by applying the streamlined procedure on a multiplug filtration clean-up column coupled with a syringe. The sorbent used for clean-up in this research is multiwalled carbon nanotubes, which was mixed with anhydrous magnesium sulfate to remove water from the extracts. This method was validated on 40 representative pesticides and apple, cabbage, and potato sample matrices spiked at two concentration levels of 10 and 100 μg/kg. It exhibited recoveries between 71 and 117% for most pesticides with RSDs 0.995 for most studied pesticides between concentration levels of 10-500 μg/L. The LOQs for 40 pesticides ranged from 2 to 50 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market fruit and vegetable samples. PMID:23939876

  16. Cleaning carbon steel

    Science.gov (United States)

    Maynard, V.

    1976-01-01

    Increased etch rate using 8% citric acid actually reduces total amount of material etched away by eliminating reprocessing that was frequently required. Time required in citrosolve solution is reduced and more protective passive coating is provided.

  17. The first chiral diene-based metal-organic frameworks for highly enantioselective carbon-carbon bond formation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sawano, Takahiro; Ji, Pengfei; McIsaac, Alexandra R.; Lin, Zekai; Abney, Carter W.; Lin, Wenbin [UC

    2016-02-01

    We have designed the first chiral diene-based metal–organic framework (MOF), E₂-MOF, and postsynthetically metalated E₂-MOF with Rh(I) complexes to afford highly active and enantioselective single-site solid catalysts for C–C bond formation reactions. Treatment of E₂-MOF with [RhCl(C₂H₄)₂]₂ led to a highly enantioselective catalyst for 1,4-additions of arylboronic acids to α,β-unsaturated ketones, whereas treatment of E₂-MOF with Rh(acac)(C₂H₄)₂ afforded a highly efficient catalyst for the asymmetric 1,2-additions of arylboronic acids to aldimines. Interestingly, E₂-MOF·Rh(acac) showed higher activity and enantioselectivity than the homogeneous control catalyst, likely due to the formation of a true single-site catalyst in the MOF. E₂-MOF·Rh(acac) was also successfully recycled and reused at least seven times without loss of yield and enantioselectivity.

  18. Ultrafast studies of organometallic photochemistry: The mechanism of carbon-hydrogen bond activation in solution

    Energy Technology Data Exchange (ETDEWEB)

    Bromberg, S.E.

    1998-05-01

    When certain organometallic compounds are photoexcited in room temperature alkane solution, they are able to break or activate the C-H bonds of the solvent. Understanding this potentially practical reaction requires a detailed knowledge of the entire reaction mechanism. Because of the dynamic nature of chemical reactions, time-resolved spectroscopy is commonly employed to follow the important events that take place as reactants are converted to products. For the organometallic reactions examined here, the electronic/structural characteristics of the chemical systems along with the time scales for the key steps in the reaction make ultrafast UV/Vis and IR spectroscopy along with nanosecond Step-Scan FTIR spectroscopy the ideal techniques to use for this study. An initial study of the photophysics of (non-activating) model metal carbonyls centering on the photodissociation of M(CO){sub 6} (M = Cr, W, Mo) was carried out in alkane solutions using ultrafast IR spectroscopy. Next, picosecond UV/vis studies of the C-H bond activation reaction of Cp{sup *}M(CO){sub 2} (M = Rh, Ir), conducted in room temperature alkane solution, are described in an effort to investigate the origin of the low quantum yield for bond cleavage ({approximately}1%). To monitor the chemistry that takes place in the reaction after CO is lost, a system with higher quantum yield is required. The reaction of Tp{sup *}Rh(CO){sub 2} (Tp{sup *} = HB-Pz{sub 3}{sup *}, Pz{sup *} = 3,5-dimethylpyrazolyl) in alkanes has a quantum yield of {approximately}30%, making time resolved spectroscopic measurements possible. From ultrafast IR experiments, two subsequently formed intermediates were observed. The nature of these intermediates are discussed and the first comprehensive reaction mechanism for a photochemical C-H activating organometallic complex is presented.

  19. Laser treatment of carbon fibre reinforced thermoplastic matrix for adhesive bonding

    Science.gov (United States)

    Genna, S.; Leone, C.; Ucciardello, N.; Giuliani, M.

    2016-05-01

    In the present study, laser surface treatment of CFRP made of PPS thermoplastic matrix by means of a 30 W Q-Switched Yb:YAG fiber laser, is investigated with the aim to improve adhesive bonding. The process parameters pulse power, scanning speed, hatch distance and scanning strategy, were varied to the aim to study the influence of the process condition on the first top resin layer removal and fibre damage. The operating window was experimentally determined. The effectiveness of laser treatment was verified by single lap shear test.

  20. Colloidal Alumina-bonded TiB2 Coating on Cathode Carbon Blocks in Aluminum Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Self-propagating high-temperature synthesis (SHS) with reduction process was used to fabricate TiB2 powder from TiO2-B2O3-Mg system. The colloidal alumina-bonded TiB2 paste was prepared and coated on the cathode carbonblocks. Various properties of the baked paste such as the corrosive resistance, thermal expansion and wettability were tested. Experimental results showed that the colloidal alumina-bonded TiB2 coating could be well wetted by liquid alum inum; and the thermal expansion coefficient of the coated material was 5.8× 10 6 ℃ -1 at 20-1000℃, which was close to that of the traditional anthracite block cathode (4× 10 6 ℃ 1); the electrical resistivity was 8 μΩ·m at 900℃ when the con tent of alumina in the coated material was about 9% in mass fraction. In addition, some other good results such as sodium resistance were also reported.

  1. Microstructure and interfacial reactions in the bonding zone of explosively welded Zr700 and carbon steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Henryk; Morgiel, Jerzy; Faryna, Marek; Miszczyk, Magdalena [Polish Academy of Sciences, Inst. of Metallurgy and Materials Science, Krakow (Poland); Prazmowski, Mariusz [Opole Univ. of Technology (Poland). Faculty of Mechanics

    2015-07-15

    The microstructure of an explosive cladding joint formed between parallel Zr700 alloy and carbon steel plates was examined with the use of scanning and transmission electron microscopes equipped with energy dispersive spectrometry. The study focused on near-the-interface microstructural changes and possible interdiffusion between the plates. At the macro-scale, the interfaces were outlined by a characteristic sharp transition, indicating that there was no mechanical mixing between the welded metals in the solid state. At the micro-scale, the melted zones often showed non-uniform swirl-like areas of a similar contrast. The nano-scale analysis revealed that the melted areas were composed of mixed amorphous and nano-crystalline phases. The bonding was always achieved by way of surface melting of the joined materials, which might be invisible for observation methods other than transmission electron microscopy.

  2. The Variety of Carbon-Metal Bonds inside Cu-ZSM-5 Zeolites: A Density Functional Theory Study

    Directory of Open Access Journals (Sweden)

    Takashi Yumura

    2010-04-01

    Full Text Available Large-scale density functional theory calculations (DFT found various types of binding of an unsaturated hydrocarbon (C2H2 and C2H4 to a ZSM-5 zeolite extraframework copper cation. We employed the DFT calculations based on the B3LYP functional to obtain local minima of an unsaturated hydrocarbon adsorbed on one or two copper cations embedded inside ZSM-5, and then compared their stabilization energies. The DFT results show that the stabilization energies are strongly dependent on the copper coordination environment as well as configurations of two copper cations. Consequently, the inner copper-carbon bonds are influenced substantially by a nanometer-scale cavity of ZSM-5.

  3. Durable ultrathin silicon nitride/carbon bilayer overcoats for magnetic heads: The role of enhanced interfacial bonding

    International Nuclear Information System (INIS)

    Pole tip recession (PTR) is one of the major issues faced in magnetic tape storage technology, which causes an increase in the magnetic spacing and hence signal loss during data readback. Despite efforts to reduce the magnetic spacing, PTR, and surface wear on the heads by using protective overcoats, most of them either employ complex fabrication processes and approaches do not provide adequate protection to the head or are too thick (∼10–20 nm), especially for future high density tape storage. In this work, we discuss an approach to reduce the PTR and surface wear at the head by developing an ultrathin ∼7 nm bilayer overcoat of silicon/silicon nitride (Si/SiNx) and carbon (C), which is totally fabricated by a cost-effective and industrial-friendly magnetron sputtering process. When compared with a monolithic C overcoat of similar thickness, the electrically insulating Si/SiNx/C bilayer overcoat was found to provide better wear protection for commercial tape heads, as demonstrated by Auger electron spectroscopic analyses after wear tests with commercial tape media. Although the microstructures of carbon in the monolithic and bilayer overcoats were similar, the improved wear durability of the bilayer overcoat was attributed to the creation of extensive interfacial bonding of Si and N with the C overcoat and the alumina-titanium carbide composite head substrate, as predicted by time-of-flight secondary ion mass spectrometry and confirmed by in-depth X-ray photoelectron spectroscopy analyses. This study highlights the pivotal role of enhanced interfaces and interfacial bonding in developing ultrathin yet wear-durable overcoats for tape heads

  4. Durable ultrathin silicon nitride/carbon bilayer overcoats for magnetic heads: The role of enhanced interfacial bonding

    Science.gov (United States)

    Yeo, Reuben J.; Dwivedi, Neeraj; Zhang, Lu; Zhang, Zheng; Lim, Christina Y. H.; Tripathy, S.; Bhatia, Charanjit S.

    2015-01-01

    Pole tip recession (PTR) is one of the major issues faced in magnetic tape storage technology, which causes an increase in the magnetic spacing and hence signal loss during data readback. Despite efforts to reduce the magnetic spacing, PTR, and surface wear on the heads by using protective overcoats, most of them either employ complex fabrication processes and approaches do not provide adequate protection to the head or are too thick (˜10-20 nm), especially for future high density tape storage. In this work, we discuss an approach to reduce the PTR and surface wear at the head by developing an ultrathin ˜7 nm bilayer overcoat of silicon/silicon nitride (Si/SiNx) and carbon (C), which is totally fabricated by a cost-effective and industrial-friendly magnetron sputtering process. When compared with a monolithic C overcoat of similar thickness, the electrically insulating Si/SiNx/C bilayer overcoat was found to provide better wear protection for commercial tape heads, as demonstrated by Auger electron spectroscopic analyses after wear tests with commercial tape media. Although the microstructures of carbon in the monolithic and bilayer overcoats were similar, the improved wear durability of the bilayer overcoat was attributed to the creation of extensive interfacial bonding of Si and N with the C overcoat and the alumina-titanium carbide composite head substrate, as predicted by time-of-flight secondary ion mass spectrometry and confirmed by in-depth X-ray photoelectron spectroscopy analyses. This study highlights the pivotal role of enhanced interfaces and interfacial bonding in developing ultrathin yet wear-durable overcoats for tape heads.

  5. Durable ultrathin silicon nitride/carbon bilayer overcoats for magnetic heads: The role of enhanced interfacial bonding

    Energy Technology Data Exchange (ETDEWEB)

    Yeo, Reuben J.; Dwivedi, Neeraj; Bhatia, Charanjit S., E-mail: elebcs@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore 117583 (Singapore); Zhang, Lu [Institute of Microelectronics (IME), A*STAR (Agency for Science, Technology, and Research), 11 Science Park Road, Singapore Science Park II, Singapore, Singapore 117685 (Singapore); Zhang, Zheng; Tripathy, S. [Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology, and Research), 3 Research Link, Singapore, Singapore 117602 (Singapore); Lim, Christina Y. H. [Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore 117575 (Singapore)

    2015-01-28

    Pole tip recession (PTR) is one of the major issues faced in magnetic tape storage technology, which causes an increase in the magnetic spacing and hence signal loss during data readback. Despite efforts to reduce the magnetic spacing, PTR, and surface wear on the heads by using protective overcoats, most of them either employ complex fabrication processes and approaches do not provide adequate protection to the head or are too thick (∼10–20 nm), especially for future high density tape storage. In this work, we discuss an approach to reduce the PTR and surface wear at the head by developing an ultrathin ∼7 nm bilayer overcoat of silicon/silicon nitride (Si/SiN{sub x}) and carbon (C), which is totally fabricated by a cost-effective and industrial-friendly magnetron sputtering process. When compared with a monolithic C overcoat of similar thickness, the electrically insulating Si/SiN{sub x}/C bilayer overcoat was found to provide better wear protection for commercial tape heads, as demonstrated by Auger electron spectroscopic analyses after wear tests with commercial tape media. Although the microstructures of carbon in the monolithic and bilayer overcoats were similar, the improved wear durability of the bilayer overcoat was attributed to the creation of extensive interfacial bonding of Si and N with the C overcoat and the alumina-titanium carbide composite head substrate, as predicted by time-of-flight secondary ion mass spectrometry and confirmed by in-depth X-ray photoelectron spectroscopy analyses. This study highlights the pivotal role of enhanced interfaces and interfacial bonding in developing ultrathin yet wear-durable overcoats for tape heads.

  6. The influence of temperature and seawater carbonate saturation state on 13C–18O bond ordering in bivalve mollusks

    Directory of Open Access Journals (Sweden)

    R. A. Eagle

    2013-07-01

    Full Text Available The shells of marine mollusks are widely used archives of past climate and ocean chemistry. Whilst the measurement of mollusk δ18O to develop records of past climate change is a commonly used approach, it has proven challenging to develop reliable independent paleothermometers that can be used to deconvolve the contributions of temperature and fluid composition on molluscan oxygen isotope compositions. Here we investigate the temperature dependence of 13C–18O bond abundance, denoted by the measured parameter Δ47, in shell carbonates of bivalve mollusks and assess its potential to be a useful paleothermometer. We report measurements on cultured specimens spanning a range in water temperatures of 5 to 25 °C, and field collected specimens spanning a range of −1 to 29 °C. In addition we investigate the potential influence of carbonate saturation state on bivalve stable isotope compositions by making measurements on both calcitic and aragonitic specimens that have been cultured in seawater that is either supersaturated or undersaturated with respect to aragonite. We find a robust relationship between Δ47 and growth temperature. We also find that the slope of a linear regression through all the Δ47 data for bivalves plotted against seawater temperature is significantly shallower than previously published inorganic and biogenic carbonate calibration studies produced in our laboratory and go on to discuss the possible sources of this difference. We find that changing seawater saturation state does not have significant effect on the Δ47 of bivalve shell carbonate in two taxa that we examined, and we do not observe significant differences between Δ47-temperature relationships between calcitic and aragonitic taxa.

  7. Modernization perspectives of the Sao Paulo State sugarcane sector through the clean development mechanism and potential carbon credits generation

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Suani Teixeira; Lora, Beatriz Acquaro [Brazilian Reference Center on Biomass (CENBIO/USP), SP (Brazil)], Emails: suani@iee.usp.br, blora@iee.usp.br

    2009-07-01

    The world-wide necessity of greenhouse gases mitigation and the intergovernmental mobilization to reach the objectives established by the United Nations Framework on Climate Change (UNFCCC) has opened space for the renewable energy increase in the world's energy matrix. In Brazil, the solid sugarcane industry currently develops business in the scope of the clean development mechanism (CDM) under the Kyoto's Protocol, by means of 18 biomass-based projects, with renewable energy generation through bagasse cogeneration at 20 Sao Paulo State's sugarcane production units. The projects activity's consists of increasing the efficiency in the bagasse cogeneration facilities, qualifying the units to sell surplus electricity to the national grid, avoiding the dispatch of the same amount of energy produced by fossil-fuelled thermal plants to that grid. The reduced emissions are measured in carbon equivalent and can be converted into negotiable credits. The objective of this study was to build a 'state of art' scenario, calculating the potential emissions reduction through CDM projects for the sugarcane sector of Sao Paulo State, in which we consider the adherence of all the production units of the State to the CDM projects. The technological parameters used to elaborate the scenario were provided by the Sao Paulo State Government Bioenergy Special Commission and the baseline factor used of 0,268 tCO{sub 2}e/MWh was the adopted by the CDM projects in operation in the State. The sugarcane database for the calculations was the production ranking provided by UNICA for the 2006/2007 season. In the most conservative scenario (40 bar bagasse) 131 units could generate 607 MWm of surplus power avoiding the emission of 1.404.593 tCO{sub 2}e/year. For the 92 bar (bagasse and straw) scenario, the units could generate 3.055 MWm of surplus power avoiding 12.199.443 tCO{sub 2}e/year. (author)

  8. Reversible CO2 Capture by Conjugated Ionic Liquids through Dynamic Covalent Carbon-Oxygen Bonds.

    Science.gov (United States)

    Pan, Mingguang; Cao, Ningning; Lin, Wenjun; Luo, Xiaoyan; Chen, Kaihong; Che, Siying; Li, Haoran; Wang, Congmin

    2016-09-01

    The strong chemisorption of CO2 is always accompanied by a high absorption enthalpy, and traditional methods to reduce the absorption enthalpy lead to decreased CO2 capacities. Through the introduction of a large π-conjugated structure into the anion, a dual-tuning approach for the improvement of CO2 capture by anion-functionalized ionic liquids (ILs) resulted in a high capacity of up to 0.96 molCO2  mol-1IL and excellent reversibility. The increased capacity and improved desorption were supported by quantum chemical calculations, spectroscopic investigations, and thermogravimetric analysis. The increased capacity may be a result of the strengthened dynamic covalent bonds in these π-electron-conjugated structures through anion aggregation upon the uptake of CO2 , and the improved desorption originates from the charge dispersion of interaction sites through the large π-electron delocalization. These results provide important insights into effective strategies for CO2 capture. PMID:27458723

  9. Covalently bonded three-dimensional carbon nanotube solids via boron induced nanojunctions

    OpenAIRE

    Hashim, Daniel P.; Narayanan, Narayanan T.; Romo-Herrera, Jose M.; Cullen, David A.; Myung Gwan Hahm; Peter Lezzi; Suttle, Joseph R.; Doug Kelkhoff; E. Muñoz-Sandoval; Sabyasachi Ganguli; Roy, Ajit K.; Smith, David J.; Robert Vajtai; Sumpter, Bobby G.; Vincent Meunier

    2012-01-01

    The establishment of covalent junctions between carbon nanotubes (CNTs) and the modification of their straight tubular morphology are two strategies needed to successfully synthesize nanotube-based three-dimensional (3D) frameworks exhibiting superior material properties. Engineering such 3D structures in scalable synthetic processes still remains a challenge. This work pioneers the bulk synthesis of 3D macroscale nanotube elastic solids directly via a boron-doping strategy during chemical va...

  10. Helium Plasma Damage of Low-k Carbon Doped Silica Film: the Effect of Si Dangling Bonds on the Dielectric Constant

    International Nuclear Information System (INIS)

    The low-k carbon doped silica film has been modified by radio frequency helium plasma at 5 Pa pressure and 80 W power with subsequent XPS, FTIR and optical emission spectroscopy analysis. XPS data indicate that helium ions have broken Si–C bonds, leading to Si–C scission with C(1s) lost seriously. The Si(2p), O(1s), peak obviously shifted to higher binding energies, indicating an increasingly oxidized Si(2p). FTIR data also show that the silanol formation increased with longer exposure time up to a week. Contrarily, the CH3 stretch, Si–C stretching bond and the ratio of the Si–O–Si cage and Si–O–Si network peak sharply decreased upon exposure to helium plasma. The OES result indicates that monovalent helium ions in plasma play a key role in damaging carbon doped silica film. So it can be concluded that the monovalent helium ions besides VUV photons can break the weak Si–C bonds to create Si dangling bonds and free methyl radicals, and the latter easily reacts with O2 from the atmosphere to generate CO2 and H2O. The bonds change is due to the Si dangling bonds combining with H2O, thereby, increasing the dielectric constant k value. (plasma technology)

  11. Helium Plasma Damage of Low-k Carbon Doped Silica Film: the Effect of Si Dangling Bonds on the Dielectric Constant

    Institute of Scientific and Technical Information of China (English)

    LI Hailing; WANG Qing; BA Dechun

    2014-01-01

    The low-k carbon doped silica film has been modified by radio frequency helium plasma at 5 Pa pressure and 80 W power with subsequent XPS,FTIR and optical emission spectroscopy analysis.XPS data indicate that helium ions have broken Si-C bonds,leading to Si-C scission with C(1s) lost seriously.The Si(2p),O(1s),peak obviously shifted to higher binding energies,indicating an increasingly oxidized Si(2p).FTIR data also show that the silanol formation increased with longer exposure time up to a week.Contrarily,the CH3 stretch,Si-C stretching bond and the ratio of the Si-O-Si cage and Si-O-Si network peak sharply decreased upon exposure to helium plasma.The OES result indicates that monovalent helium ions in plasma play a key role in damaging carbon doped silica film.So it can be concluded that the monovalent helium ions besides VUV photons can break the weak Si-C bonds to create Si dangling bonds and free methyl radicals,and the latter easily reacts with O2 from the atmosphere to generate CO2 and H2O.The bonds change is due to the Si dangling bonds combining with H2O,thereby,increasing the dielectric constant k value.

  12. Effect of SiO2 on the Preparation and Properties of Pure Carbon Reaction Bonded Silicon Carbide Ceramics

    Institute of Scientific and Technical Information of China (English)

    WU Qi-de; GUO Bing-jian; YAN Yong-gao; ZHAO Xiu-jian; HONG Xiao-lin

    2004-01-01

    Effect of SiO2 content and sintering process on the composition and properties of Pure CarbonReaction Bonded Silicon Carbide (PCRBSC) ceramics prepared with C - SiO2 green body by infiltrating siliconwas presented. The infiltrating mechanism of C - SiO2 preform was also explored. The experimental results indicatethat the shaping pressure increases with the addition of SiO2 to the preform, and the pore size of the body turnedfiner and distributed in a narrower range, which is beneficial to decreasing the residual silicon content in the sin-tered materials and to avoiding shock off, thus increasing the conversion rate of SiC. SiO2 was deoxidized by car-bon at a high temperature and the gaseous SiO and CO produced are the main reason to the crack of the body atan elevated temperature. If the green body is deposited at 1800℃ in vacuum before infiltration crack will not beproduced in the preform and fully dense RBSC can be obtained. The ultimate material has the following properties:a density of3.05-3.12g/cm3 ,a strength of 580±32MPa and a hardness of (HRA)91-92.3.

  13. Low-carbon economy development trend and clean and effective utilization of coal%低碳经济与煤的清洁高效利用

    Institute of Scientific and Technical Information of China (English)

    杨明

    2011-01-01

    煤炭是中国的主要能源,实现低碳经济的关键是煤的清洁高效利用.提出煤炭洗选、煤制合成天然气和煤基多联产作为短、中、长期的对策建议.%Coal is the main source of energy in China, clean and effective utilization of coal determines the development trend of low-carbon economy. Provide coal washing, synthetic natural gas (SNG) production from coal, coalbased co-production respectively serving as short-term, mid-term,long-term developmental tasks.

  14. PhnY and PhnZ comprise a new oxidative pathway for enzymatic cleavage of a carbon-phosphorus bond

    DEFF Research Database (Denmark)

    McSorley, Fern R.; Wyatt, Peter W.; Martinez, Ascuncion;

    2012-01-01

    The sequential activities of PhnY, an α-ketoglutarate/Fe(II)-dependent dioxygenase, and PhnZ, a Fe(II)-dependent enzyme of the histidine-aspartate motif hydrolase family, cleave the carbon-phosphorus bond of the organophosphonate natural product 2-aminoethylphosphonic acid. PhnY adds a hydroxyl...

  15. Covalently Bonded Graphene-Carbon Nanotube Hybrid for High-Performance Thermal Interfaces

    DEFF Research Database (Denmark)

    Chen, Jie; Walther, Jens H.; Koumoutsakos, Petros

    2015-01-01

    The remarkable thermal properties of graphene and carbon nanotubes (CNTs) have been the subject of intensive investigations for the thermal management of integrated circuits. However, the small contact area of CNTs and the large anisotropic heat conduction of graphene have hindered their...... extraction. Through computer simulations, it is demonstrated that the G-CNT outperforms few-layer graphene by more than 2 orders of magnitude for the c-axis heat transfer, while its thermal resistance is 3 orders of magnitude lower than the state-of-the-art TIMs. We show that heat can be removed from the G...

  16. Clean data

    CERN Document Server

    Squire, Megan

    2015-01-01

    If you are a data scientist of any level, beginners included, and interested in cleaning up your data, this is the book for you! Experience with Python or PHP is assumed, but no previous knowledge of data cleaning is needed.

  17. Effects of vertically aligned carbon nanotubes on shear performance of laminated nanocomposite bonded joints

    Directory of Open Access Journals (Sweden)

    Davood Askari and Mehrdad N Ghasemi-Nejhad

    2012-01-01

    Full Text Available The main objective is to improve the most commonly addressed weakness of the laminated composites (i.e. delamination due to poor interlaminar strength using carbon nanotubes (CNTs as reinforcement between the laminae and in the transverse direction. In this work, a chemical vapor deposition technique has been used to grow dense vertically aligned arrays of CNTs over the surface of chemically treated two-dimensionally woven cloth and fiber tows. The nanoforest-like fabrics can be used to fabricate three-dimensionally reinforced laminated nanocomposites. The presence of CNTs aligned normal to the layers and in-between the layers of laminated composites is expected to considerably enhance the properties of the laminates. To demonstrate the effectiveness of our approach, composite single lap-joint specimens were fabricated for interlaminar shear strength testing. It was observed that the single lap-joints with through-the-thickness CNT reinforcement can carry considerably higher shear stresses and strains. Close examination of the test specimens showed that the failure of samples with CNT nanoforests was completely cohesive, while the samples without CNT reinforcement failed adhesively. This concludes that the adhesion of adjacent carbon fabric layers can be considerably improved owing to the presence of vertically aligned arrays of CNT nanoforests.

  18. Effects of vertically aligned carbon nanotubes on shear performance of laminated nanocomposite bonded joints

    International Nuclear Information System (INIS)

    The main objective is to improve the most commonly addressed weakness of the laminated composites (i.e. delamination due to poor interlaminar strength) using carbon nanotubes (CNTs) as reinforcement between the laminae and in the transverse direction. In this work, a chemical vapor deposition technique has been used to grow dense vertically aligned arrays of CNTs over the surface of chemically treated two-dimensionally woven cloth and fiber tows. The nanoforest-like fabrics can be used to fabricate three-dimensionally reinforced laminated nanocomposites. The presence of CNTs aligned normal to the layers and in-between the layers of laminated composites is expected to considerably enhance the properties of the laminates. To demonstrate the effectiveness of our approach, composite single lap-joint specimens were fabricated for interlaminar shear strength testing. It was observed that the single lap-joints with through-the-thickness CNT reinforcement can carry considerably higher shear stresses and strains. Close examination of the test specimens showed that the failure of samples with CNT nanoforests was completely cohesive, while the samples without CNT reinforcement failed adhesively. This concludes that the adhesion of adjacent carbon fabric layers can be considerably improved owing to the presence of vertically aligned arrays of CNT nanoforests. (paper)

  19. Quantitative Evaluation of Contamination on Dental Zirconia Ceramic by Silicone Disclosing Agents after Different Cleaning Procedures

    Directory of Open Access Journals (Sweden)

    Sebastian Wille

    2015-05-01

    Full Text Available The aim of this study was to evaluate the effectiveness of cleaning procedures for air-abraded zirconia after contamination with two silicone disclosing agents. Air-abraded zirconia ceramic specimens (IPS e.max ZirCAD were contaminated with either GC Fit Checker white or GC Fit Checker II. Untreated zirconia specimens were used as control. Afterwards the surfaces were cleaned either with waterspray or ultrasonically in 99% isopropanol or using a newly developed cleaning paste (Ivoclean. After cleaning X-ray photoelectron spectroscopy (XPS was performed and the relative peak intensities of Zr, C and Si were used for a qualitative comparison of the residuals. There was no significant difference between the two different silicone disclosing agents. An additional cleaning step with isopropanol led to a significantly lower amount of residuals on the surface, but an additional cleaning process with Ivoclean did not reduce the amount of carbon residuals in comparison to the isopropanol cleaning. Just the silicone amount on the surface was reduced. None of the investigated cleaning processes removed all residuals from the contaminated surface. Standard cleaning processes do not remove all residuals of the silicone disclosing agent from the surface. This may lead to a failure of the resin-ceramic bonding.

  20. Covalently bonded three-dimensional carbon nanotube solids via boron induced nanojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL; Terrones Maldonado, Humberto [ORNL; Terrones Maldonado, Mauricio [ORNL; Ajayan, Pullikel M [Rice University; Hashim, Daniel [Rice University; Romo Herrera, Jose M [ORNL; Cullen, David [ORNL; Munoz-Sandoval, Emilio [IPICyT; Smith, David J [Arizona State University; Vajtai, Robert [Rice University; Roy, Ajit K [ORNL; Ganguli, Sabyasachi [Arizona State University; Kelkhoff, Doug [University of Illinois, Urbana-Champaign; Suttle, Joesph [University of Illinois, Urbana-Champaign; Lezzi, Peter [Rensselaer Polytechnic Institute (RPI); Hahm, Gwan [Rice University; Narayanan, Narayanan [Rice University

    2012-01-01

    The establishment of covalent junctions between carbon nanotubes (CNTs) and the modification of their straight tubular morphology are two strategies needed to successfully synthesize nanotube-based three-dimensional (3D) frameworks exhibiting superior material properties. Engineering such 3D structures in scalable synthetic processes still remains a challenge. This work pioneers the bulk synthesis of 3D macroscale nanotube elastic solids directly via a boron-doping strategy during chemical vapor deposition, which influences the formation of atomic-scale elbow junctions and nanotube covalent interconnections. Detailed elemental analysis revealed that the elbow junctions are preferred sites for excess boron atoms, indicating the role of boron and curvature in the junction formation mechanism, in agreement with our first principle theoretical calculations. Exploiting this material s ultra-light weight, super-hydrophobicity, high porosity, thermal stability, and mechanical flexibility, the strongly oleophilic sponge-like solids are demonstrated as unique reusable sorbent scaffolds able to efficiently remove oil from contaminated seawater even after repeated use.

  1. Low-carbon innovation and technology transfer in latecomer countries: Insights from solar PV in the clean development mechanism

    OpenAIRE

    Lema, Rasmus; Lema, Adrian

    2016-01-01

    This paper examines the organizational arrangements for technology supply in solar photovoltaic projects in the Clean Development Mechanism (CDM). It shows that while lower middle-income countries typically import solar PV equipment into CDM projects, China, India and Thailand have begun to use new organizational arrangements for technology transfer which reflect the overall industry maturity in the solar PV sectors in these countries. This has great potential for long-term climate change mit...

  2. Suppressed Demand and the Carbon Markets: Does development have to become dirty before it qualifies to become clean?

    OpenAIRE

    Gavaldão, Marina; Battye, William; Grapeloup, Mathieu; François, Yann

    2012-01-01

    Suppressed Demand refers to a situation where Minimum Services Levels (MSL) necessary for human development are unavailable to people or only available to an inadequate level. Numerous barriers, such as low income levels or lack of infrastructure and skills prevent access to MSLs, such as potable water, cooking energy, lighting and electrification. We investigate the concept of suppressed demand as it applies to Clean Development Mechanism (CDM) and market based incentives for GHG emission re...

  3. Pentaatomic planar tetracoordinate carbon molecules [XCAl(3)](q) [(X,q) = (B,-2), (C,-1), (N,0)] with C-X multiple bonding.

    Science.gov (United States)

    Cui, Zhong-Hua; Shao, Chang-Bin; Gao, Si-Meng; Ding, Yi-Hong

    2010-11-01

    Among the fascinating planar tetracoordinate carbon (ptC) species, pentaatomic molecules belong to the smallest class, well-known as "pptC". It has been generally accepted that the planarity of pptC structure is realized via the "delocalization" of the p(z) lone pair at the central carbon and the ligand-ligand bonding interaction. Although "localization" is as key driving force in organic chemistry as "delocalization", the "localization" concept has not been applied to the design of pptC molecules, to the best of our knowledge. In this paper, we apply the "localization" strategy to design computationally a series of new pptC. It is shown that the central carbon atom and one "electronegative" ligand atom X (compared to the Al ligand) effectively form a highly localized C-X multiple bond, converting the lone pair at the central carbon to a two-center two-electron π-bond. At the aug-cc-pVTZ-B3LYP, MP2 and CCSD(T) levels, the designed 18-valence-electron pptC species [XCAl(3)](q); [(X,q) = (B,-2), (C,-1), (N,0)] are found to each possess a stable ptC structure bearing a C-X double bond, indicated by the structural, molecular orbital, Wiberg bonding, potential energy surface and Born-Oppenheimer molecular dynamics (BOMD) analysis. Moreover, our OVGF calculations showed that the presently disclosed (yet previously unconsidered) pptC structure of [C(2)Al(3)](-) could well account for the observed photoelectron spectrum (previously only ascribed to a close-energy fan-like structure). Therefore, [C(2)Al(3)](-) could be the first pptC that bears the highly localized C-X double bond that has been experimentally generated. Notably, the pptC structure is the respective global minimum point for [BCAl(3)](2-) and [NCAl(3)], and the counterion(s) would further stabilize [BCAl(3)](2-) and [C(2)Al(3)](-). Thus, these newly designed pptC species with interesting bonding structure should be viable for future experimental characterization. The presently applied "localization" approach

  4. Unique properties of C,C'-linked nido-biscarborane tetraanions. Synthesis, structure and bonding of ruthenium monocarbollide via unprecedented cage carbon extrusion.

    Science.gov (United States)

    Zhao, Da; Zhang, Jiji; Lin, Zhenyang; Xie, Zuowei

    2016-08-21

    Four reaction pathways have been found in the reaction of a C,C'-linked nido-biscarborane tetraanionic salt with [Ru(p-cymene)Cl2]2, leading to the isolation and structural characterization of redox, triple cage B-H oxidative addition, cage expansion and cage carbon extrusion products. Among these, the unprecedented cage carbon extrusion results in the formation of a new 6π-electron carboranyl ligand [C2B10H10](2-). The bonding interactions between this ligand and the Ru(ii) center have also been discussed on the basis of DFT calculations. PMID:27405999

  5. Broadening the Appeal of Marginal Abatement Cost Curves: Capturing Both Carbon Mitigation and Development Benefits of Clean Energy Technologies; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Cowlin, S.; Cochran, J.; Cox, S.; Davison, C.; van der Gaast, Y.

    2012-08-01

    Low emission development strategies (LEDS) articulate policies and implementation plans that enable countries to advance sustainable, climate-resilient development and private sector growth while significantly reducing the greenhouse gas (GHG) emissions traditionally associated with economic growth. In creating a LEDS, policy makers often have access to information on abatement potential and costs for clean energy technologies, but there is a scarcity of economy-wide approaches for evaluating and presenting information on other dimensions of importance to development, such as human welfare, poverty alleviation, and energy security. To address this shortcoming, this paper proposes a new tool for communicating development benefits to policy makers as part of a LEDS process. The purpose of this tool is two-fold: 1. Communicate development benefits associated with each clean energy-related intervention; 2. Facilitate decision-making on which combination of interventions best contributes to development goals. To pilot this tool, the authors created a visual using data on developmental impacts identified through the Technology Needs Assessment (TNA) project in Montenegro. The visual will then be revised to reflect new data established through the TNA that provides information on cost, GHG mitigation, as well as the range and magnitude of developmental impacts.

  6. Quantitative assessment of the multiplicity of carbon-halogen bonds: carbenium and halonium ions with F, Cl, Br, and I.

    Science.gov (United States)

    Kalescky, Robert; Zou, Wenli; Kraka, Elfi; Cremer, Dieter

    2014-03-13

    CX (X = F, Cl, Br, I) and CE bonding (E = O, S, Se, Te) was investigated for a test set of 168 molecules using the local CX and CE stretching force constants k(a) calculated at the M06-2X/cc-pVTZ level of theory. The stretching force constants were used to derive a relative bond strength order (RBSO) parameter n. As alternative bond strength descriptors, bond dissociation energies (BDE) were calculated at the G3 level or at the two-component NESC (normalized elimination of the small component)/CCSD(T) level of theory for molecules with X = Br, I or E = Se, Te. RBSO values reveal that both bond lengths and BDE values are less useful when a quantification of the bond strength is needed. CX double bonds can be realized for Br- or I-substituted carbenium ions where as suitable reference the double bond of the corresponding formaldehyde homologue is used. A triple bond cannot be realized in this way as the diatomic CX(+) ions with a limited π-donor capacity for X are just double-bonded. The stability of halonium ions increases with the atomic number of X, which is reflected by a strengthening of the fractional (electron-deficient) CX bonds. An additional stability increase of up to 25 kcal/mol (X = I) is obtained when the X(+) ion can form a bridged halonium ion with ethene such that a more efficient 2-electron-3-center bonding situation is created. PMID:24555526

  7. Carbonyl carbon transverse relaxation dispersion measurements and ms-μs timescale motion in a protein hydrogen bond network

    International Nuclear Information System (INIS)

    A constant-time, Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation, R2, dispersion experiment for carbonyl carbons was designed and executed to detect μs-ms time-scale dynamics of protein backbone carbonyl sites. Because of the large (ca. 55 Hz) Cα-C' J-coupling, the carbonyl signal intensity is strongly modulated as the spacing between CPMG pulses is varied, in uniformly 13C enriched proteins, unless care is taken to minimize the perturbation of the Cα magnetization by the CPMG pulses. CPMG pulse trains consisting of either a band-selective pulse, such as RE-BURP, or rectangular (with an excitation null in the Cα region of the spectrum) pulses were employed in order to minimize C' signal modulation by Cα-C' J-coupling. The performance of these types of CPMG refocusing pulses was assessed by computer simulation, and by comparing dispersion profiles measured for (1) uniformly [13C,15N, 2H] (2H at non-labile hydrogen sites) labeled, and (2) uniformly 15N/selectively-13C' labeled samples of HIV-1 protease bound to a potent inhibitor, DMP323. In addition, because the uniformly 13C/15N/2H labeled sample was well suited to measure 15N and 1H R2 dispersion as well as 13C' dispersion, conformational exchange in the inter subunit β-sheet hydrogen-bond network of the inhibitor-bound protease was elucidated using relaxation dispersion data of all three types of nuclei

  8. Carbonyl carbon transverse relaxation dispersion measurements and ms-{mu}s timescale motion in a protein hydrogen bond network

    Energy Technology Data Exchange (ETDEWEB)

    Ishima, Rieko [National Institute of Dental and Craniofacial Research, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Molecular Structural Biology Unit (United States); Baber, James; Louis, John M.; Torchia, Dennis A. [National Institute of Dental and Craniofacial Research, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Molecular Structural Biology Unit (United States)

    2004-06-15

    A constant-time, Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation, R{sub 2}, dispersion experiment for carbonyl carbons was designed and executed to detect {mu}s-ms time-scale dynamics of protein backbone carbonyl sites. Because of the large (ca. 55 Hz) C{sub {alpha}}-C' J-coupling, the carbonyl signal intensity is strongly modulated as the spacing between CPMG pulses is varied, in uniformly {sup 13}C enriched proteins, unless care is taken to minimize the perturbation of the C{sub {alpha}} magnetization by the CPMG pulses. CPMG pulse trains consisting of either a band-selective pulse, such as RE-BURP, or rectangular (with an excitation null in the C{sub {alpha}} region of the spectrum) pulses were employed in order to minimize C' signal modulation by C{sub {alpha}}-C' J-coupling. The performance of these types of CPMG refocusing pulses was assessed by computer simulation, and by comparing dispersion profiles measured for (1) uniformly [{sup 13}C,{sup 15}N, {sup 2}H] ({sup 2}H at non-labile hydrogen sites) labeled, and (2) uniformly {sup 15}N/selectively-{sup 13}C' labeled samples of HIV-1 protease bound to a potent inhibitor, DMP323. In addition, because the uniformly {sup 13}C/{sup 15}N/{sup 2}H labeled sample was well suited to measure {sup 15}N and {sup 1}H R{sub 2} dispersion as well as {sup 13}C' dispersion, conformational exchange in the inter subunit {beta}-sheet hydrogen-bond network of the inhibitor-bound protease was elucidated using relaxation dispersion data of all three types of nuclei.

  9. Carbonyl carbon transverse relaxation dispersion measurements and ms-micros timescale motion in a protein hydrogen bond network.

    Science.gov (United States)

    Ishima, Rieko; Baber, James; Louis, John M; Torchia, Dennis A

    2004-06-01

    A constant-time, Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation, R(2), dispersion experiment for carbonyl carbons was designed and executed to detect micros-ms time-scale dynamics of protein backbone carbonyl sites. Because of the large (ca. 55 Hz) C(alpha)-C' J-coupling, the carbonyl signal intensity is strongly modulated as the spacing between CPMG pulses is varied, in uniformly (13)C enriched proteins, unless care is taken to minimize the perturbation of the C(alpha) magnetization by the CPMG pulses. CPMG pulse trains consisting of either a band-selective pulse, such as RE-BURP, or rectangular (with an excitation null in the C(alpha) region of the spectrum) pulses were employed in order to minimize C' signal modulation by C(alpha)-C' J-coupling. The performance of these types of CPMG refocusing pulses was assessed by computer simulation, and by comparing dispersion profiles measured for (1) uniformly [(13)C,(15)N, (2)H] ((2)H at non-labile hydrogen sites) labeled, and (2) uniformly (15)N/selectively-(13)C' labeled samples of HIV-1 protease bound to a potent inhibitor, DMP323. In addition, because the uniformly (13)C/(15)N/(2)H labeled sample was well suited to measure (15)N and (1)H R(2) dispersion as well as (13)C' dispersion, conformational exchange in the inter subunit beta-sheet hydrogen-bond network of the inhibitor-bound protease was elucidated using relaxation dispersion data of all three types of nuclei. PMID:15014232

  10. Actinide-to-carbon bonds in Cp2An(alkyl)2, -(butadiene), -(metallacyclopentadiene), and -(cyclobutadiene) complexes

    International Nuclear Information System (INIS)

    The electronic structure of actinide bis(cyclopentadienyl)dialkyl, -butadiene, -metallacyclopentadiene, and -cyclobutadiene complexes is examined. Some Cp*2Th(alkyl)2 complexes display an interesting structural deformation in which a Th-C-C(alkyl) angle (α) opens up considerably. A molecular orbital analysis of Cp2Th(C2H5)2 traces the deformation to the characteristic shape of the d/sub σ/ fragment orbital of Cp2Th(C2H5)+. The potential energy curve for the ethyl pivoting was found to be very soft, with a shallow minimum at α ∼ 1600. Nonrigidity of the ethyl orientation indicates that not only an α hydrogen but also a β hydrogen can come close to Th without a loss of Th-C bond strength; the discussion should provide a theoretical basis for understanding important aspects of C-H activation chemistry involving actinide centers. The Cp2An(s-cis-C4H6) complex was calculated to be 0.74 eV (Th) or 0.42 eV (U) more stable than its s-trans-C4H6 isomer, in contrast to the analogous Cp2Zr(C4H6) complex where the stability of the two geometrical isomers was well-balanced. The σ2,π character of the s-cis-C4H6 coordination to An is somewhat less pronounced than that in the Zr congener, in harmony with the X-ray structures, while highly negative charges are accumulated on the s-cis-C4H6 terminal carbons

  11. Copper(I)-catalyzed carbon-halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

    OpenAIRE

    Iwamoto, Hiroaki; Kubota, Koji; Yamamoto, Eiji; Ito, Hajime

    2015-01-01

    The selective boryl substitution of alkyl halides bearing terminal C=C double bonds has been achieved using a copper(I)/tricyclohexylphosphine or copper(I)/o-diphenylphosphinophenol catalyst. This reaction represents a useful complementary approach to conventional procedures for the hydroboration of C=C double bonds or the borylative cyclization of alkyl halides bearing terminal alkenes.

  12. Genesis Solar Wind Sample 61422: Experiment in Variation of Sequence of Cleaning Solvent for Removing Carbon-Bearing Contamination

    Science.gov (United States)

    Allton, J. H.; Kuhlman, K. R.; Allums, K. K.; Gonzalez, C. P.; Jurewicz, A. J. G.; Burnett, D. S.; Woolum, D. S.

    2015-01-01

    The recovered Genesis collector fragments are heavily contaminated with crash-derived particulate debris. However, megasonic treatment with ultra-pure-water (UPW; resistivity (is) greater than18 meg-ohm-cm) removes essentially all particulate contamination greater than 5 microns in size [e.g.1] and is thus of considerable importance. Optical imaging of Si sample 60336 revealed the presence of a large C-rich particle after UPW treatment that was not present prior to UPW. Such handling contamination is occasionally observed, but such contaminants are normally easily removed by UPW cleaning. The 60336 particle was exceptional in that, surprisingly, it was not removed by additional UPW or by hot xylene or by aqua regia treatment. It was eventually removed by treatment with NH3-H2O2. Our best interpretation of the origin of the 60336 particle was that it was adhesive from the Post-It notes used to stabilize samples for transport from Utah after the hard landing. It is possible that the insoluble nature of the 60336 particle comes from interaction of the Post-It adhesive with UPW. An occasional bit of Post-It adhesive is not a major concern, but C particulate contamination also occurs from the heat shield of the Sample Return Capsule (SRC) and this is mixed with inorganic contamination from the SRC and the Utah landing site. If UPW exposure also produced an insoluble residue from SRC C, this would be a major problem in chemical treatments to produce clean surfaces for analysis. This paper reports experiments to test whether particulate contamination was removed more easily if UPW treatment was not used.

  13. Synthesis, structure, and reactivity of iridium perfluorocarbene complexes: regio- and stereo-specific addition of HCl across a metal carbon double bond.

    Science.gov (United States)

    Yuan, Jian; Bourgeois, Cheryl J; Rheingold, Arnold L; Hughes, Russell P

    2015-12-01

    Reductive activation of an α-fluorine in the perfluoroalkyl complexes Cp*(L)(i)Ir-CF2RF using Mg/graphite leads to perfluorocarbene complexes Cp*(L)Ir[double bond, length as m-dash]CFRF (L = CO, PMe3; RF = CF3, C2F5, C6F5). New complexes E-Cp*(PMe3)Ir[double bond, length as m-dash]CFC2F5 and E-Cp*(CO)Ir[double bond, length as m-dash]CFC6F5 have been characterized by single crystal X-ray diffraction studies, and a comparison of metric parameters with previously reported analogues is reported. Experimental NMR and computational DFT (B3LYP/LACV3P**++) studies agree that for Ir[double bond, length as m-dash]CFRF complexes (RF = CF3, CF2CF3) the thermodynamic preference for the E or Z isomer depends on the steric requirements of ligand L; when L = CO the Z-isomer (F cis to Cp*) is preferred and for L = PMe3 the E-isomer is preferred. When reduction of the precursors is carried out in the dark the reaction is completely selective to produce E- or Z-isomers. Exposure of solutions of these compounds to ambient light results in slow conversion to a photostationary non-equilibrium mixture of E and Z isomers. In the dark, these E/Z mixtures convert thermally to their preferred E or Z equilibrium geometries in an even slower reaction. A study of the temperature dependent kinetics of this dark transformation allows ΔG(‡)298 for rotation about the Ir[double bond, length as m-dash]CFCF3 double bond to be experimentally determined as 25 kcal mol(-1); a DFT/B3LYP/LACV3P**++ calculation of this rotation barrier is in excellent agreement (27 kcal mol(-1)) with the experimental value. Reaction of HCl with toluene solutions of Cp*(L)Ir[double bond, length as m-dash]CFRF (L = CO, PMe3) or Cp*(CO)Ir[double bond, length as m-dash]C(CF3)2 at low temperature resulted in regiospecific addition of HCl across the metal carbon double bond, ultimately yielding Cp*(L)Ir(CHFRF)Cl and Cp*(CO)Ir[CH(CF3)2]Cl. Reaction of HCl with single E or Z diastereomers of Cp*(L)Ir[double bond, length as m

  14. Effect of heat treatment and cleanness of ultra low carbon bainitic (ULCB) steel on its impact toughness

    International Nuclear Information System (INIS)

    The small variations in sulphur and carbon concentrations can have a major influence on the impact transition temperature (ITT) of ultra low carbon HSLA-100 steel which has been quenched in water and tempered (WQ and T). Since the average carbon concentration is very low thus sensitivity of ITT to heat treatment parameters depends also on the yield strength increase due to precipitation effect of εCu phase. The regression analysis has been used to establish equations taking into account those parameters. The properties of a mixed microstructure formed from partially austenitic regions have been also considered. The fine austenitic grains transform into more desirable fine bainitic ferrite phases with lower hardness values and higher toughness. On the other hand, if cooling rate is sufficiently large, then the carbon enriched austenite transforms partially into hard martensite and some of remaining untransformed austenite being retained to ambient temperature. Because hard martensite islands are located in much softer surroundings consisting of tempered ferrite, they do not cause a general reduction in impact toughness tests. Due to further grain refinement of microstructure the measured toughness on Charpy V specimens can be very high at low temperatures. The very detrimental effect of sulphur in ULCB steel has been confirmed by presented results. (author)

  15. Towards defect free EUVL reticles: Carbon and particle removal by single dry cleaning process, and pattern repair by HIM

    NARCIS (Netherlands)

    Koster, N.B.; Molkenboer, F.T.; Veldhoven, E. van; Oostrom, S.

    2011-01-01

    We report on our findings on EUVL reticle contamination removal, inspection and repair. We show that carbon contamination can be removed without damage to the reticle by our plasma process. Also organic particles, simulated by PSL spheres, can be removed from both the surface of the absorber as well

  16. Micro-image analysis in the diffusion-bonded zone of Fe3Al/Q235 carbon steel dissimilar materials

    Indian Academy of Sciences (India)

    Wang Juan; Li Yajiang; Wu Huiqiang; Ren Jiangwei

    2002-10-01

    The chemical composition of the second phase precipitation in the vacuum diffusion-bonded zone of Fe3Al intermetallic compound and Q235 carbon steel was analysed by means of electron probe microanalyser (EPMA). The relative content of the second phase precipitation and grain size was evaluated through a micro-image analyser. The percentage of Fe and Al content in the diffusion zone was measured by EPMA. The results indicated that the relative content of the second phase precipitation rich in carbon and chromium at the Fe3Al/Q235 interface was much higher. With the transition from Fe3Al intermetallic compound to Q235 carbon steel across Fe3Al/Q235 interface, the grain diameter decreased from 250 m to 112 m, Al atom content decreased from 27% to 15%, while Fe atom content increased from 76% to 96%.

  17. Hydrogen bonding in polyanilines

    Energy Technology Data Exchange (ETDEWEB)

    Bahceci, S. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey)); Toppare, L. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey)); Yurtsever, E. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey))

    1994-11-29

    Hydrogen bonding between poly(bisphenol A carbonate) (PC) and polyaniline (PAn) is analyzed using semi-empirical quantum methodology. Fully optimized AM1 molecular orbital calculations are reported for various aniline structures (monomer, dimer and trimer), the monomer of the PC and the hydrogen-bonded model of PAn-PC oligomer. ((orig.))

  18. Probing the Carbon-phosphorus Bond Coupling in Low-temperature Phosphine PH3—Methane CH4 Interstellar Ice Analogues

    Science.gov (United States)

    Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-03-01

    Phosphine, which has now been confirmed around the carbon-rich star IRC+10216, provides the first example of a phosphorus-containing single bond in interstellar or circumstellar media. While four compounds containing both phosphorus and carbon have been discovered, none contain a carbon-phosphorus single bond. Here, we show that this moiety is plausible from the reaction of phosphine with methane in electron-irradiated interstellar ice analogues. Fractional sublimation allows for detection of individual products at distinct temperatures using reflectron time-of-flight mass spectrometry (ReTOF) coupled with vacuum ultraviolet photoionization. This method produced phosphanes and methylphosphanes as large as P8H10 and CH3P8H9, which demonstrates that a phosphorus-carbon bond can readily form and that methylphosphanes sublime at 12-17 K higher temperatures than the non-organic phosphanes. Also, irradiated ices of phosphine with deuterated-methane untangle the reaction pathways through which these methylphosphanes were formed and identified radical recombination to be preferred over carbene/phosphinidene insertion reactions. In addition, these ReTOF results confirm that CH3PH2 and CH6P2 can form via insertion of carbene and phosphinidene and that the methylenediphosphine (PH2CH2PH2) isomer forms in the ices, although methylphosphine (CH3P2H3) is likely the more abundant isomer and that phosphanes and organophosphanes preferentially fragment via the loss of a phosphino group when photoionized. While the formation of methylphosphine is overall endoergic, the intermediates produced by interactions with energetic electrons proceed toward methylphosphine favorably and barrierlessly and provide plausible mechanisms toward hitherto unidentified interstellar compounds.

  19. Origin of bulklike structure and bond length disorder of Pt37 and Pt6Ru31 clusters on carbon: comparison of theory and experiment.

    Science.gov (United States)

    Wang, Lin-Lin; Khare, Sanjay V; Chirita, Valeriu; Johnson, D D; Rockett, Angus A; Frenkel, Anatoly I; Mack, Nathan H; Nuzzo, Ralph G

    2006-01-11

    We describe a theoretical analysis of the structures of self-organizing nanoparticles formed by Pt and Ru-Pt on carbon support. The calculations provide insights into the nature of these metal particle systems-ones of current interest for use as the electrocatalytic materials of direct oxidation fuel cells-and clarify complex behaviors noted in earlier experimental studies. With clusters deposited via metallo-organic Pt or PtRu(5) complexes, previous experiments [Nashner et al. J. Am. Chem. Soc. 1997, 119, 7760; Nashner et al. J. Am. Chem. Soc. 1998, 120, 8093; Frenkel et al. J. Phys. Chem. B 2001, 105, 12689] showed that the Pt and Pt-Ru based clusters are formed with fcc(111)-stacked cuboctahedral geometry and essentially bulklike metal-metal bond lengths, even for the smallest (few atom) nanoparticles for which the average coordination number is much smaller than that in the bulk, and that Pt in bimetallic [PtRu(5)] clusters segregates to the ambient surface of the supported nanoparticles. We explain these observations and characterize the cluster structures and bond length distributions using density functional theory calculations with graphite as a model for the support. The present study reveals the origin of the observed metal-metal bond length disorder, distinctively different for each system, and demonstrates the profound consequences that result from the cluster/carbon-support interactions and their key role in the structure and electronic properties of supported metallic nanoparticles. PMID:16390140

  20. Neutral-atom scattering from random isolated adsorbate atoms on clean metal surfaces: Oxygen and carbon monoxide on nickel (001)

    International Nuclear Information System (INIS)

    The intensity I of the specular beam of a helium nozzle beam scattered from a Ni(001) surface has been measured as a function of adsorbate coverage CTHETA for both oxygen and CO exposures at 350 K for different angles of incidence. A linear relationship is found between ln (I/I0) (I0, the intensity of the specular beam from the clean surface) and CTHETA up to CTHETA = 0.15 monolayer of O on Ni and CTHETA = 0.1 monolayer of CO on Ni. A model is proposed in which the scattering is governed by the repulsive part of the gas-surface potential, the latter being described by a hard-wall corrugation. A constant attractive well depth and a temperature-dependent vibration amplitude of the atoms are also incorporated into the model. The adsorbate atoms are treated as a shot noise on a flat metal surface. By means of suitable averaging, a formula is found that explains the linear dependence indicated. From the best fit of the model to the experimental data, a set of parameters describing the corrugation of a single adsorbate is derived. Cross sections for the helium-adatom scattering are 65 and 26 A2 for CO and O, respectively. The corresponding corrugations have been fitted with Gaussians of height 0.62 A (for CO) and 0.32 A (for O)

  1. Clean, premium-quality chars: Demineralized and carbon enriched. Quarterly report, December 1, 1991--February 29, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Smith, G.V. [Southern Illinois Univ., Carbondale, IL (United States)

    1992-08-01

    The interaction of methane, methane/oxygen, helium, and hydrogen with IBC-102 coal samples ({le} 2mg) has been investigated in a thermogravimetric reactor at 20{degrees}C--650{degrees}C. The results show that the reactive gases are converting some of the mineral matter of the coal into catalysts through chemical reactions (reduction or oxidation). Also, these gases (except He) dissolve in the softened coal. Added clays (kaolinite and Ca-montmorillonite) increase the reactivity of the coal. This higher reactivity may be attributed to the fact that clays may serve as catalysts for methane activation, may prevent the coal agglomeration, and/or may increase the number of active sites for the reaction by modification of the geometric structure of the coal surface. Differential Scanning Calorimetry (DSC) experiments show that clean coal (no mineral matter) devolatilizes at a lower temperature than raw coal. Also, the preoxidation at 150{degrees}C for 50 minutes results in a 13{degrees} lowering of the devolatilization temperature. ISDR-FTIR experiments suggest that phenol groups of the coal play an important role in the cross-linkage of the coal structure when thermally treated.

  2. Hot and Dry Cleaning of Biomass-Gasified Gas Using Activated Carbons with Simultaneous Removal of Tar, Particles, and Sulfur Compounds

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-05-01

    Full Text Available This study proposes a gas-cleaning process for the simultaneous removal of sulfur compounds, tar, and particles from biomass-gasified gas using Fe-supported activated carbon and a water-gas shift reaction. On a laboratory scale, the simultaneous removal of H2S and COS was performed under a mixture of gases (H2/CO/CO2/CH4/C2H4/N2/H2S/COS/steam. The reactions such as COS + H2 → H2S + CO and COS + H2O → H2S + CO2 and the water-gas shift reaction were promoted on the Fe-supported activated carbon. The adsorption capacity with steam was higher than that without steam. On a bench scale, the removal of impurities from a gas derived from biomass gasification was investigated using two activated filters packed with Fe-supported activated carbon. H2S and COS, three- and four-ring polycyclic aromatic hydrocarbons (PAHs, and particles were removed and a water-gas shift reaction was promoted through the first filter at 320–350 °C. The concentrations of H2S and COS decreased to less than 0.1 ppmv. Particles and the one- and two-ring PAHs, except for benzene, were then removed through the second filter at 60–170 °C. The concentration of tar and particles decreased from 2428 to 102 mg Nm−3 and from 2244 to 181 mg Nm−3, respectively.

  3. 硅胶担载的高锰酸钾对烯烃碳碳双键的氧化%Carbon-Carbon Double Bond Cleavage by Silica-supported Potassium Permanganate under Conditions Free of Organic Solvent

    Institute of Scientific and Technical Information of China (English)

    王文军; 戴乾圜

    2002-01-01

    An improved simple method for carbon-carbon double bond cleavage by silica-supported potassium permanganate was described and a possible mechanism was proposed.%在无有机溶剂做介质的条件下,用硅胶吸附的高锰酸钾氧化6种难溶于水的液态烯烃,得到了双键发生断裂的氧化产物.该反应操作简便,反应快,收率好.此外,对硅胶的活化作用机制进行了浅析.

  4. Clean catch urine sample

    Science.gov (United States)

    Urine culture - clean catch; Urinalysis - clean catch; Clean catch urine specimen; Urine collection - clean catch ... lips" (labia). You may be given a special clean-catch kit that contains sterile wipes. Sit on ...

  5. Role of interfacial carbon layer in the thermal diffusivity/conductivity of silicon carbide fiber-reinforced reaction-bonded silicon nitride matrix composites

    Science.gov (United States)

    Bhatt, Hemanshu; Donaldson, Kimberly Y.; Hasselman, D. P. H.; Bhatt, Ramakrishna T.

    1992-01-01

    Experiments were carried out on samples of reaction-bonded silicon nitride uniaxially reinforced by SiC monofilaments with and without a 3-micron-thick carbon-rich coating. It is found that a combination of a carbon coatings on the fibers and an interfacial gap due to the thermal expansion mismatch in the composite can significantly (by a factor of 2) lower the effective thermal diffusivity in the direction transverse to the fiber. At atmospheric pressure, gaseous conduction across the interfacial gap makes a significant contribution to the heat transfer across the interface, indicated by significantly lower values of the effective thermal diffusivity under vacuum than in nitrogen or helium at atmospheric pressure.

  6. Dry Cleaning

    OpenAIRE

    Shirley, Lindsey; Weller, Chanae

    2010-01-01

    Despite its name, commercial dry cleaning is not actually a “dry” process. Clothes are immersed in a solvent, most commonly perchlorethylene (perc), instead of in water. Perc or other similar solvents are effective in the removal of oil and grease-based stains without damaging or shrinking sensitive fabrics, unlike a regular detergents and fabric softeners.

  7. MICROWAVE-ASSISTED CHEMISTRY: SYNTHESIS OF AMINES AND HETEROCYCLES VIA CARBON-NITROGEN BOND FORMATION IN AQUEOUS MEDIA

    Science.gov (United States)

    Improved C-N bond formation under MW influence is demonstrated by a) solventless three-component coupling reaction to generate propargyl amines that uses only Cu (I); b) aqueous N-alkylation of amines by alkyl halides that proceeds expeditiously in the presence of NaOH to deliver...

  8. Weak intramolecular and intermolecular hydrogen bonding of benzyl alcohol, 2-phenylethanol and 2-phenylethylamine in the adsorption on graphitized thermal carbon black.

    Science.gov (United States)

    Varfolomeeva, V V; Terentev, A V

    2015-10-01

    The paper discusses the role of weak intra- and intermolecular hydrogen bonds in the adsorption of benzyl alcohol, 2-phenylethanol and 2-phenylethylamine on graphitized thermal carbon black (GTCB). Using the B3LYP/aug-cc-pVDZ, B3LYP/aug-cc-pVTZ methods and the molecular-statistical theory of adsorption we found the structural and energetic parameters of the conformers to be stable in the gas phase and in the adsorbed state. The contribution of weak OHπ, NHπ, CHO hydrogen bonds to the stabilization of the conformers was defined by the method of non-covalent interactions (NCI). Based on the difference in the experimental and calculated values of the Henry constant Δ ln K1 calculation of the thermodynamic characteristics of adsorption (TCA) has been shown. To obtain a high predictive power of molecular-statistical calculation it was necessary to take due account of the structural features of flexible molecules in the adsorbed state. A significant impact of the weak OHπGTCB intermolecular hydrogen bond of benzyl alcohol on the TCA values has been established. PMID:26327209

  9. Mechanism of ribonucleotide reductase from Herpes simplex virus type 1. Evidence for 3' carbon-hydrogen bond cleavage and inactivation by nucleotide analogs

    International Nuclear Information System (INIS)

    Isotope effects of 2.5, 2.1, and 1.0 were measured on the conversion of [3'-3H]ADP, [3'-H]UDP, and [5-3H] UDP to the corresponding 2'-deoxynucleotides by herpes simplex virus type 1 ribonucleotide reductase. These results indicate that the reduction of either purine or pyrimidine nucleotides requires cleavage of the 3' carbon-hydrogen bond of the substrate. The substrate analogs 2'-chloro-2'-deoxyuridine 5'-diphosphate (ClUDP), 2'-deoxy-2'-fluorouridine 5'-diphosphate, and 2'-azido-2'-deoxyuridine 5'-diphosphate were time-dependent inactivators of the herpes simplex virus type 1 ribonucleotide reductase. Incubation of [3'-3H]ClUDP with the enzyme was accompanied by time-dependent release of 3H to the solvent. Reaction of [beta-32P]ClUDP with the reductase resulted in the production of inorganic pyrophosphate. These results are consistent with the enzyme-mediated cleavage of the 3' carbon-hydrogen bond of ClUDP and the subsequent conversion of the nucleotide to 2-methylene-3(2H)furanone, as previously reported with the Escherichia coli ribonucleotide reductase

  10. Effects of carbonyl bond, metal cluster dissociation, and evaporation rates on predictions of nanotube production in high-pressure carbon monoxide

    Science.gov (United States)

    Scott, Carl D.; Smalley, Richard E.

    2003-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the conformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

  11. Carbon supported polyindole-5-carboxylic acid covalently bonded with pyridine-2,4-diamine copper complex as a non-precious oxygen reduction catalyst

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The carbon supported catalyst was prepared by a novel method. • The composite is a non-precious electrocatalyst with excellent stability and electrocatalytic activity. • The oxygen reduction reaction of the composite is a four electron based mixed mode. - Abstract: Indole-5-carboxylic acid monomer was electropolymerized on carbon modified glass carbon (GC) electrode, followed by the covalent bonding with pyridine-2,4-diamine by using 1-ethyl-(3-(dimethyl-amino-propyl)carbodiimide (EDAC), N-hydroxysulfosuccinimide sodium salt (NHS) catalyst, and then was complexed with copper ions to obtain the composite (CuINPD/C). The morphology and the chemical composition of the CuINPD/C catalyst were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Electrochemical measurements such as cyclic voltammetry, rotating disk electrode, rotating ring-disk electrode and electrochemical impedance spectroscopy were applied to obtain the mechanisms of the oxygen reduction reaction (ORR). All electrochemical measurements demonstrate that CuINPD/C is a good catalyst with excellent stability due to copper ions doping and carbon modification, which play a key role in increasing the current density and enhancing the charge transfer kinetics. Moreover, the average electron transfer number is about 3.1, indicating the ORR of CuINPD/C may takes a coexisting pathway involving both the two-electron and four-electron transfers

  12. Synthesis of Biaryls through Nickel-Catalyzed Suzuki-Miyaura Coupling of Amides by Carbon-Nitrogen Bond Cleavage.

    Science.gov (United States)

    Shi, Shicheng; Meng, Guangrong; Szostak, Michal

    2016-06-01

    The first Ni-catalyzed Suzuki-Miyaura coupling of amides for the synthesis of widely occurring biaryl compounds through N-C amide bond activation is reported. The reaction tolerates a wide range of electron-withdrawing, electron-neutral, and electron-donating substituents on both coupling partners. The reaction constitutes the first example of the Ni-catalyzed generation of aryl electrophiles from bench-stable amides with potential applications for a broad range of organometallic reactions. PMID:27101428

  13. Silicon carbide wafer bonding by modified surface activated bonding method

    Science.gov (United States)

    Suga, Tadatomo; Mu, Fengwen; Fujino, Masahisa; Takahashi, Yoshikazu; Nakazawa, Haruo; Iguchi, Kenichi

    2015-03-01

    4H-SiC wafer bonding has been achieved by the modified surface activated bonding (SAB) method without any chemical-clean treatment and high temperature annealing. Strong bonding between the SiC wafers with tensile strength greater than 32 MPa was demonstrated at room temperature under 5 kN force for 300 s. Almost the entire wafer has been bonded very well except a small peripheral region and few voids. The interface structure was analyzed to verify the bonding mechanism. It was found an amorphous layer existed as an intermediate layer at the interface. After annealing at 1273 K in vacuum for 1 h, the bonding tensile strength was still higher than 32 MPa. The interface changes after annealing were also studied. The results show that the thickness of the amorphous layer was reduced to half after annealing.

  14. Controlling the Adsorption of Ruthenium Complexes on Carbon Surfaces through Noncovalent Bonding with Pyrene Anchors: An Electrochemical Study.

    Science.gov (United States)

    Kohmoto, Mayuko; Ozawa, Hiroaki; Yang, Li; Hagio, Toshihiro; Matsunaga, Mariko; Haga, Masa-Aki

    2016-05-01

    Surface modifications of carbon nanomaterials, such as graphene or carbon nanotubes, through noncovalent π-π interactions between π-conjugated carbon surfaces and pyrene anchors have received much attention on account of the applications of these materials in organic electronic and sensor devices. Despite the rapidly expanding use of pyrene anchors, little is known about the number of pyrene groups required in order to achieve a stable attachment of molecules on nanocarbon surfaces. So far, systematic studies on such surface modifications through adsorption isotherms and desorption behavior of molecules still remain scarce. In this study, we have investigated the effect of the number of pyrene anchors in redox-active Ru complexes on their adsorption on carbon nanomaterials through noncovalent π-π interactions. The Ru(II/III) couple was used as a redox marker in order to determine the surface coverage on nanocarbon surfaces such as highly oriented pyrolytic graphite (HOPG), single-walled carbon nanotubes (SWCNTs), and multiwalled carbon nanotubes (MWCNTs). The amount of surface coverage as well as the kinetic stability of the Ru complexes was thereby observed to be directly proportional to the number of pyrene groups present in the ligands. The desorption rate from HOPG electrode increased in the order Ru-1 with eight pyrene groups (k = 2.0 × 10(-5) s(-1)) compounds having more than two and/or optimally four pyrene groups revealed a stable adsorption on the nanocarbon surfaces. The heterogeneous electron transfer rate between the Ru complex, Ru-2, and the carbon nanomaterials increased in the order SWCNTs (kET = 1.3 s(-1)) < MWCNTs (ϕ = 5-9 nm) (kET = 4.0 s(-1)) < MWCNTs (ϕ = 110-170 nm) (kET = 14.9 s(-1)) < HOPG (kET = 110 s(-1)). PMID:27065057

  15. CO2-pellet cleaning process cuts costs

    International Nuclear Information System (INIS)

    The Non Destructive Cleaning (NDC) process is truly a ''dry process'' that generates no secondary waste streams. Since no solid grit or aggregate is used, there is no need for bulk radioactive solid waste handling equipment. Moreover, since no chemicals are used, the mobile decontamination facility requires no radioactive chemical processing or mixed waste handling facilities. Instead the NDC process uses solid carbon dioxide particles propelled by dry compressed air as the cleaning medium. The carbon dioxide particles shatter upon impact with the surface of the material to be cleaned and flash into dry carbon dioxide gas. This flashing into gas results in a rapid volume expansion of about ten to one. The cleaning action is due to the rapidly expanding carbon dioxide gas flashing into the surface of the item to be cleaned (which is porous at the microscopic level) and flushing foreign materials out. The microscopic particles of foreign material are captured on high efficiency particulate filters. Larger sized fragments are lifted off the surface by the flashing carbon dioxide gas, fall to the bottom of the cleaning area and are vacuumed away to dry air filters. The NDC process also has the advantage that it does not attack the surface of the material being cleaned, making it unique among cleaning processes. (author)

  16. Nutrient, organic carbon, and chloride concentrations and loads in selected Long Island Sound tributaries—Four decades of change following the passage of the Federal Clean Water Act

    Science.gov (United States)

    Mullaney, John R.

    2016-01-01

    Trends in long-term water-quality and streamflow data from 14 water-quality monitoring sites in Connecticut were evaluated for water years 1974–2013 and 2001–13, coinciding with implementation of the Clean Water Act of 1972 and the Connecticut Nitrogen Credit Exchange program, as part of an assessment of nutrient and chloride concentrations and loads discharged to Long Island Sound. In this study, conducted by the U.S. Geological Survey in cooperation with the Connecticut Department of Energy and Environmental Protection, data were evaluated using a recently developed methodology of weighted regressions with time, streamflow, and season. Trends in streamflow were evaluated using a locally weighted scatterplot smoothing method. Annual mean streamflow increased at 12 of the 14 sites averaging 8 percent during the entire study period, primarily in the summer months, and increased by an average of 9 percent in water years 2001–13, primarily during summer and fall months. Downward trends in flow-normalized nutrient concentrations and loads were observed during both periods for most sites for total nitrogen, total Kjeldahl nitrogen, nitrite plus nitrate nitrogen, total phosphorus, and total organic carbon. Average flow-normalized loads of total nitrogen decreased by 23.9 percent for the entire period and 10.9 percent for the period of water years 2001‒13. Major factors contributing to decreases in flow-normalized loads and concentrations of these nutrients include improvements in wastewater treatment practices, declining atmospheric wet deposition of nitrogen, and changes in land management and land use.

  17. Surface characterization in composite and titanium bonding: Carbon fiber surface treatments for improved adhesion to thermoplastic polymers

    Science.gov (United States)

    Devilbiss, T. A.; Wightman, J. P.

    1987-01-01

    The effect of anodization in NaOH, H2SO4, and amine salts on the surface chemistry of carbon fibers was examined by X-ray photoelectron spectroscopy (XPS). The surfaces of carbon fibers after anodization in NaOH and H2SO4 were examined by scanning transmission electron microscopy (STEM), angular dependent XPS, UV absorption spectroscopy of the anodization bath, secondary ion mass spectrometry, and polar/dispersive surface energy analysis. Hercules AS-4, Dexter Hysol XAS, and Union Carbide T-300 fibers were examined by STEM, angular dependent XPS, and breaking strength measurement before and after commercial surface treatment. Oxygen and nitrogen were added to the fiber surfaces by anodization in amine salts. Analysis of the plasmon peak in the carbon 1s signal indicated that H2SO4 anodization affected the morphological structure of the carbon fiber surface. The work of adhesion of carbon fibers to thermoplastic resins was calculated using the geometric mean relationship. A correlation was observed between the dispersive component of the work of adhesion and the interfacial adhesion.

  18. On clean ideals

    OpenAIRE

    Miaosen Chen; Huanyin Chen

    2003-01-01

    We introduce the notion of clean ideal, which is a natural generalization of clean rings. It is shown that every matrix ideal over a clean ideal of a ring is clean. Also we prove that every ideal having stable range one of a regular ring is clean. These generalize the corresponding results for clean rings.

  19. Ab initio study of chemical bond interactions between covalently functionalized carbon nanotubes via amide, ester and anhydride linkages

    Science.gov (United States)

    Ben Doudou, Bessem; Chen, Jun; Vivet, Alexandre; Poilâne, Christophe

    2016-03-01

    In this paper, we have investigated the chemical bond interactions between covalently functionalized zigzag (5,0) and (8,0) SWCNT-SWCNT via various covalent linkages. Side-to-side junctions connected via amide, ester and anhydride linkages were particularly studied. The geometries and energy of the forming reaction were investigated using first-principles density functional theory. Furthermore, the band structures and the total density of states (DOS) of the junctions have also been analyzed. Our results show that several promising structures could be obtained by using chemical connection strategy and particularly the junctions formed by coupling amino functionalized SWCNT and carboxylic acid functionalized SWCNT was more favorable.

  20. Preferential formation of 13C- 18O bonds in carbonate minerals, estimated using first-principles lattice dynamics

    Science.gov (United States)

    Schauble, Edwin A.; Ghosh, Prosenjit; Eiler, John M.

    2006-05-01

    Equilibrium constants for internal isotopic exchange reactions of the type: Ca12C18O16O2+Ca13C16O3↔Ca13C18O16O2+Ca12C16O3 for individual CO 32- groups in the carbonate minerals calcite (CaCO 3), aragonite (CaCO 3), dolomite (CaMg(CO 3) 2), magnesite (MgCO 3), witherite (BaCO 3), and nahcolite (NaHCO 3) are calculated using first-principles lattice dynamics. Calculations rely on density functional perturbation theory (DFPT) with norm-conserving planewave pseudopotentials to determine the vibrational frequencies of isotopically substituted crystals. Our results predict an ˜0.4‰ excess of 13C18O16O22- groups in all studied carbonate minerals at room-temperature equilibrium, relative to what would be expected in a stochastic mixture of carbonate isotopologues with the same bulk 13C/ 12C, 18O/ 16O, and 17O/ 16O ratios. The amount of excess 13C18O16O22- decreases with increasing temperature of equilibration, from 0.5‰ at 0 °C to <0.1‰ at 300 °C, suggesting that measurements of multiply substituted isotopologues of carbonate could be used to infer temperatures of ancient carbonate mineral precipitation and alteration events, even where the δ 18O of coexisting fluids is uncertain. The predicted temperature sensitivity of the equilibrium constant is ˜0.003‰/°C at 25 °C. Estimated equilibrium constants for the formation of 13C18O16O22- are remarkably uniform for the variety of minerals studied, suggesting that temperature calibrations will also be applicable to carbonate minerals not studied here without greatly compromising accuracy. A related equilibrium constant for the reaction: Ca12C18O16O2+Ca12C17O16O2↔Ca12C18O17O16O+Ca12C16O3 in calcite indicates formation of 0.1‰ excess 12C 18O 17O 16O 2- at 25 °C. In a conventional phosphoric acid reaction of carbonate to form CO 2 for mass-spectrometric analysis, molecules derived from 13C18O16O22- dominate (˜96%) the mass 47 signal, and 12C 18O 17O 16O 2- contributes most of the remainder (3%). This suggests

  1. Effect of C–O Bonding on the Stability and Energetics of High-Energy Nitrogen-Carbon Molecules N10C2 and N16C2

    Directory of Open Access Journals (Sweden)

    Douglas L. Strout

    2014-01-01

    Full Text Available Molecules consisting of nitrogen have been the subject of much attention due to their potential as high-energy materials. Complex molecules consisting entirely of nitrogen can be subject to rapid decomposition, and therefore other atoms are incorporated into the structure to enhance stability. Previous studies have explored the incorporation of carbon atoms into otherwise all-nitrogen cages molecules. The current study involves two such cages, N10C2 and N16C2, whose structures are derived from N12 and N18, respectively. The N10C2 and N16C2 cages in this study are modified by bonding groups O3 and CO3 to determine the effect on the relative energies between the isomers and on the thermodynamic energy release properties. Energetic trends for N10C2 and N16C2 are calculated and discussed.

  2. Clean Restructuring: Design Elements for Low-Carbon Wholesale Markets and Beyond. A 21st Century Power Partnership Thought Leadership Report

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Monisha [National Renewable Energy Lab. (NREL), Golden, CO (United States); Valenzuela, Jose Maria [World Wildlife Fund, Mexico DF (Mexico); Mora, Hector Alejandro Beltran [Energy Regulatory Commission of Mexico, Mexico DF (United States); Moller Porst, Kim [Danish Energy Agency, Copenhagen (Denmark); Hasselager, Anders [Danish Energy Agency, Copenhagen (Denmark); Friis-Jensen, Sandra [Danish Energy Agency, Copenhagen (Denmark); Vingaard, Mette [Danish Energy Agency, Copenhagen (Denmark); Wigand, Fabian [Ecofys, London (England); Tiedemann, Silvana [Ecofys, London (England); Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zinaman, Owen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Logan, Jeffrey [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Countries around the world are in various stages of reforming and restructuring their power systems to better meet development needs and decarbonization commitments. Changes in technology, business models, societal needs, and environmental goals are increasing pressure on countries to consider improvements to their power systems. This report addresses key issues associated with clean restructuring--the transition from traditional, vertically integrated utilities to competitive wholesale markets that rely increasingly on variable renewable electricity sources, demand response, and other clean energy options. The report also includes case studies from Mexico, Denmark, and Germany to provide real-world examples of clean restructuring from different perspectives.

  3. Diffusivity of Al and Fe near the diffusion bonding interface of Fe3Al with low carbon steel

    Indian Academy of Sciences (India)

    Li Yajiang; Wang Juan; Yin Yansheng; Ma Haijun

    2005-02-01

    The distribution of elements near the Fe3Al/Q235 diffusion bonding interface was computed by the diffusion equation as well as measured by means of EPMA. The results indicated close agreement between the two for iron and aluminium. Diffusion coefficient in the interface transition zone is larger than that in the Fe3Al and Q235 steel at the same temperature, which is favourable to elemental diffusion. The diffusion distance near the Fe3Al/Q235 interface increased with increasing heating temperature, , and the holding time, . The relation between the width of the interface transition zone, , and the holding time, , conformed to parabolic growth law: 2 = 4.8 × 104 exp(– 133/RT) ( – 0). The width of the interface transition zone does not increase significantly for holding times beyond 60 min.

  4. First example of the correlated calculation of the one-bond tellurium-carbon spin-spin coupling constants: Relativistic effects, vibrational corrections, and solvent effects.

    Science.gov (United States)

    Rusakova, Irina L; Rusakov, Yury Yu; Krivdin, Leonid B

    2016-06-01

    This work reports on the comprehensive calculation of the NMR one-bond spin-spin coupling constants (SSCCs) involving carbon and tellurium, (1) J((125) Te,(13) C), in four representative compounds: Te(CH3 )2 , Te(CF3 )2 , Te(CCH)2 , and tellurophene. A high-level computational treatment of (1) J((125) Te,(13) C) included calculations at the SOPPA level taking into account relativistic effects evaluated at the 4-component RPA and DFT levels of theory, vibrational corrections, and solvent effects. The consistency of different computational approaches including the level of theory of the geometry optimization of tellurium-containing compounds, basis sets, and methods used for obtainig spin-spin coupling values have also been discussed in view of reproducing the experimental values of the tellurium-carbon SSCCs. Relativistic corrections were found to play a major role in the calculation of (1) J((125) Te,(13) C) reaching as much as almost 50% of the total value of (1) J((125) Te,(13) C) while relativistic geometrical effects are of minor importance. The vibrational and solvent corrections account for accordingly about 3-6% and 0-4% of the total value. It is shown that taking into account relativistic corrections, vibrational corrections and solvent effects at the DFT level essentially improves the agreement of the non-relativistic theoretical SOPPA results with experiment. © 2016 Wiley Periodicals, Inc. PMID:26931355

  5. Bifacial dye-sensitized solar cells from covalent-bonded polyaniline-multiwalled carbon nanotube complex counter electrodes

    Science.gov (United States)

    Zhang, Huihui; He, Benlin; Tang, Qunwei; Yu, Liangmin

    2015-02-01

    Exploration of cost-effective counter electrodes (CEs) and enhancement of power conversion efficiency have been two persistent objectives for dye-sensitized solar cells (DSSCs). In the current work, polyaniline-multiwalled carbon nanotube (PANi-MWCNT) complexes are synthesized by a reflux method and employed as CE materials for bifacial DSSCs. Owing to the high optical transparency of PANi-MWCNT complex CE, the incident light from rear side can compensate for the incident light from TiO2 anode. The charge-transfer ability and electrochemical behaviors demonstrate the potential utilization of PANi-MWCNT complex CEs in robust bifacial DSSCs. The electrochemical properties as well as photovoltaic performances are optimized by adjusting MWCNT dosages. A maximum power conversion efficiency of 9.24% is recorded from the bifacial DSSC employing PANi-8 wt‰ MWCNT complex CE for both irradiation, which is better than 8.08% from pure PANi CE.

  6. Evidence for a Proton Transfer Network and a Required Persulfide-Bond-Forming Cysteine Residue in Ni-Containing Carbon Monoxide Dehydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Eun Jin Kim; Jian Feng; Matthew R. Bramlett; Paul A. Lindahl

    2004-05-18

    OAK-B135 Carbon monoxide dehydrogenase from Moorella thermoacetica catalyzes the reversible oxidation of CO to CO2 at a nickel-iron-sulfur active-site called the C-cluster. Mutants of a proposed proton transfer pathway and of a cysteine residue recently found to form a persulfide bond with the C-cluster were characterized. Four semi-conserved histidine residues were individually mutated to alanine. His116 and His122 were essential to catalysis, while His113 and His119 attenuated catalysis but were not essential. Significant activity was ''rescued'' by a double mutant where His116 was replaced by Ala and His was also introduced at position 115. Activity was also rescued in double mutants where His122 was replaced by Ala and His was simultaneously introduced at either position 121 or 123. Activity was also ''rescued'' by replacing His with Cys at position 116. Mutation of conserved Lys587 near the C-cluster attenuated activity but did not eliminate it. Activity was virtually abolished in a double mutant where Lys587 and His113 were both changed to Ala. Mutations of conserved Asn284 also attenuated activity. These effects suggest the presence of a network of amino acid residues responsible for proton transfer rather than a single linear pathway. The Ser mutant of the persulfide-forming Cys316 was essentially inactive and displayed no EPR signals originating from the C-cluster. Electronic absorption and metal analysis suggests that the C-cluster is absent in this mutant. The persulfide bond appears to be essential for either the assembly or stability of the C-cluster, and/or for eliciting the redox chemistry of the C-cluster required for catalytic activity.

  7. Evidence for a Proton Transfer Network and a Required Persulfide-Bond-Forming Cysteine Residue in Ni-Containing Carbon Monoxide Dehydrogenases

    International Nuclear Information System (INIS)

    OAK-B135 Carbon monoxide dehydrogenase from Moorella thermoacetica catalyzes the reversible oxidation of CO to CO2 at a nickel-iron-sulfur active-site called the C-cluster. Mutants of a proposed proton transfer pathway and of a cysteine residue recently found to form a persulfide bond with the C-cluster were characterized. Four semi-conserved histidine residues were individually mutated to alanine. His116 and His122 were essential to catalysis, while His113 and His119 attenuated catalysis but were not essential. Significant activity was ''rescued'' by a double mutant where His116 was replaced by Ala and His was also introduced at position 115. Activity was also rescued in double mutants where His122 was replaced by Ala and His was simultaneously introduced at either position 121 or 123. Activity was also ''rescued'' by replacing His with Cys at position 116. Mutation of conserved Lys587 near the C-cluster attenuated activity but did not eliminate it. Activity was virtually abolished in a double mutant where Lys587 and His113 were both changed to Ala. Mutations of conserved Asn284 also attenuated activity. These effects suggest the presence of a network of amino acid residues responsible for proton transfer rather than a single linear pathway. The Ser mutant of the persulfide-forming Cys316 was essentially inactive and displayed no EPR signals originating from the C-cluster. Electronic absorption and metal analysis suggests that the C-cluster is absent in this mutant. The persulfide bond appears to be essential for either the assembly or stability of the C-cluster, and/or for eliciting the redox chemistry of the C-cluster required for catalytic activity

  8. Neutron structure of human carbonic anhydrase II in complex with methazolamide: mapping the solvent and hydrogen-bonding patterns of an effective clinical drug

    Directory of Open Access Journals (Sweden)

    Mayank Aggarwal

    2016-09-01

    Full Text Available Carbonic anhydrases (CAs; EC 4.2.1.1 catalyze the interconversion of CO2 and HCO3−, and their inhibitors have long been used as diuretics and as a therapeutic treatment for many disorders such as glaucoma and epilepsy. Acetazolamide (AZM and methazolamide (MZM, a methyl derivative of AZM are two of the classical CA inhibitory drugs that have been used clinically for decades. The jointly refined X-ray/neutron structure of MZM in complex with human CA isoform II (hCA II has been determined to a resolution of 2.2 Å with an Rcryst of ∼16.0%. Presented in this article, along with only the second neutron structure of a clinical drug-bound hCA, is an in-depth structural comparison and analyses of differences in hydrogen-bonding network, water-molecule orientation and solvent displacement that take place upon the binding of AZM and MZM in the active site of hCA II. Even though MZM is slightly more hydrophobic and displaces more waters than AZM, the overall binding affinity (Ki for both of the drugs against hCA II is similar (∼10 nM. The plausible reasons behind this finding have also been discussed using molecular dynamics and X-ray crystal structures of hCA II–MZM determined at cryotemperature and room temperature. This study not only allows a direct comparison of the hydrogen bonding, protonation states and solvent orientation/displacement of AZM and MZM, but also shows the significant effect that the methyl derivative has on the solvent organization in the hCA II active site.

  9. P-clean rings

    OpenAIRE

    Weixing Chen

    2006-01-01

    In this paper we unify the structures of various clean rings by introducing the notion of P-clean rings. Some properties of P-clean rings are investigated, which generalize the known results on clean rings, semiclean rings, n-clean rings, and so forth. By the way, we answer a question of Xiao and Tong on n-clean rings in the negative.

  10. Comparison of Bond Character in Hydrocarbons and Fullerenes

    OpenAIRE

    Snoke, D. W.; Cardona, M.; Sanguinetti, S.; Benedek, G

    1996-01-01

    We present a comparison of the bond polarizabilities for carbon-carbon bonds in hydrocarbons and fullerenes, using two different models for the fullerene Raman spectrum and the results of Raman measurements on ethane and ethylene. We find that the polarizabilities for single bonds in fullerenes and hydrocarbons compare well, while the double bonds in fullerenes have greater polarizability than in ethylene.

  11. Research of simulation of calcium carbonate on pollution of reverse osmosis process and cleaning membrane%反渗透膜碳酸钙污染过程模拟以及膜清洗研究

    Institute of Scientific and Technical Information of China (English)

    吕建国; 蒲瑜

    2012-01-01

    采用氯化钙和碳酸氢钙配置原水,模拟反渗透膜使用环境,测定膜污染后膜性能的变化趋势,并对膜进行了清洗,对比了不同阶段膜通量的恢复情况,并比较了不同清洗温度下膜通量的恢复情况。结果表明:在本实验条件下,膜通量随着膜污染的加剧呈现出先快后慢的下降趋势,而脱盐率呈先慢后快的下降趋势;污染的膜经过酸洗后,膜性能恢复到初始的98.6%;清洗温度越高,膜通量恢复越好。%The calcium chloride and calcium hydrogen carbonate configuration of water, simulations using reverse osmosis membrane environment, determination of membrane fouling membrane performance trend, and has carried on the clean to the membrane, compares the different stages of membrane flux recovery, membrane flux and compares the different cleaning temperature recovery. Result indicated :The membrane flux presents after the membrane pollution aggravating is first quick the slow drop tendency; But after desahs rate assumes is first slow the quick drop tendency;The membrane performance restores initial to 98.6% after the cleaning pollution membrane by acid; Cleaning the higher the temperature, flux recovery is better.

  12. A surface treatment technique of electrochemical oxidation to simultaneously improve the interfacial bonding strength and the tensile strength of PAN-based carbon fibers

    International Nuclear Information System (INIS)

    Electrochemical oxidation surface treatment of polyacrylonitrile-based carbon fibers (CFs) in 0.5 M ammonium oxalate aqueous solution for 94 s with the electric current density being 0.6 mA cm-2 resulted in simultaneous improvements of interfacial bonding strength and tensile strength by ∼8.6% and ∼16.6%, respectively. The improvements were due to the following reasons: (1) besides creating active surface functional groups, the electrochemical oxidation treatment with optimal processing conditions also generated a suitable electrolytic etching capability, which was powerful enough to remove mechanically weak carbonaceous components deposited on the surface of CFs, while was gentle enough not to distinguishably remove structurally ordered sheath region of CFs; (2) the treatment also refined the graphitic crystallites in the sheath region and created additional crystalline impingements/boundaries that could resist to crack growth; and (3) the electrochemical oxidation that preferably started from sharp edges including the tips of micro-cracks mitigated the stress development and propagation. XRD, SEM, Raman, FT-IR, XPS, and an electronic single-filament tensile tester were used to study the structural, morphological, chemical, and mechanical properties of the CFs before and after the treatment. A theoretical model, namely 'physical and chemical dual effects through layer-by-layer electrolytic etching', was proposed to explain the improvements.

  13. Positioning a Carbon-Fluorine Bond over the π Cloud of an Aromatic Ring: A Different Type of Arene Activation.

    Science.gov (United States)

    Holl, Maxwell Gargiulo; Struble, Mark D; Singal, Prakhar; Siegler, Maxime A; Lectka, Thomas

    2016-07-11

    It is known that the fluoro group has only a small effect on the rates of electrophilic aromatic substitutions. Imagine instead a carbon-fluorine (C-F) bond positioned tightly over the π cloud of an aryl ring-such an orthogonal, noncovalent arrangement could instead stabilize a positively charged arene intermediate or transition state, giving rise to novel electrophilic aromatic substitution chemistry. Herein, we report the synthesis and study of molecule 1, containing a rigid C-F⋅⋅⋅Ar interaction that plays a prominent role in both its reaction chemistry and spectroscopy. For example, we established that the C-F⋅⋅⋅Ar interaction can bring about a >1500 fold increase in the relative rate of an aromatic nitration reaction, affording functionalization on the activated ring exclusively. Overall, these results establish fluoro as a through-space directing/activating group that complements the traditional role of fluorine as a slightly deactivating aryl substituent in nitrations. PMID:27145463

  14. Facile Isolation of Adsorbent-Free Long and Highly-Pure Chirality-Selected Semiconducting Single-Walled Carbon Nanotubes Using A Hydrogen-bonding Supramolecular Polymer

    Science.gov (United States)

    Toshimitsu, Fumiyuki; Nakashima, Naotoshi

    2015-12-01

    The ideal form of semiconducting-single-walled carbon nanotubes (sem-SWNTs) for science and technology is long, defect-free, chirality pure and chemically pure isolated narrow diameter tubes. While various techniques to solubilize and purify sem-SWNTs have been developed, many of them targeted only the chiral- or chemically-purity while sacrificing the sem-SWNT intrinsic structural identities by applying strong ultra-sonication and/or chemical modifications. Toward the ultimate purification of the sem-SWNTs, here we report a mild-conditioned extraction of the sem-SWNTs using removable supramolecular hydrogen-bonding polymers (HBPs) that are composed of dicarboxylic- or diaminopyridyl-fluorenes with ~70%-(8,6)SWNT selective extraction. Replacing conventional strong sonication techniques by a simple shaking using HPBs was found to provide long sem-SWNTs (>2.0 μm) with a very high D/G ratio, which was determined by atomic force microscopy observations. The HBPs were readily removed from the nanotube surfaces by an outer stimulus, such as a change in the solvent polarities, to provide chemically pure (8,6)-enriched sem-SWNTs. We also describe molecular mechanics calculations to propose possible structures for the HBP-wrapped sem-SWNTs, furthermore, the mechanism of the chiral selectivity for the sorted sem-SWNTs is well explained by the relationship between the molecular surface area and mass of the HBP/SWNT composites.

  15. Green Solvents for Precision Cleaning

    Science.gov (United States)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

    2013-01-01

    Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the moderate processing conditions of 323 K, 13.8 MPa, 30 min and 750 rpm.

  16. r-clean rings

    OpenAIRE

    Ashrafi, Nahid; Nasibi, Ebrahim

    2011-01-01

    An element of a ring R is called clean if it is the sum of an idempotent and a unit. A ring R is called clean if each of its element is clean. An element r \\in R called regular if r = ryr for some y \\in R. The ring R is regular if each of its element is regular. In this paper we define a ring is r-clean if each of its elements is the sum of a regular and an idempotent element. We give some relations between r-clean and clean rings. Finally we investigate some properties of r-clean rings.

  17. Cleaning of GaN(2110) surfaces

    International Nuclear Information System (INIS)

    The cleaning of GaN(2110) surfaces was investigated by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and low-energy electron diffraction. Two different two-step cleaning methods, performed under ultrahigh-vacuum conditions, were carried out and compared. The first cleaning step of both methods is thermal degassing. The second step is either the deposition of metallic gallium followed by redesorption or an exposure to active nitrogen from a radio frequency nitrogen plasma source. Upon storage in a glovebox (N2 atmosphere) and transfer to ultrahigh vacuum under dry nitrogen, carbon and oxygen were identified as the major contaminants. A significant decrease in oxygen and carbon was achieved by thermal degassing at 750 deg. C under ultrahigh-vacuum conditions. By applying a subsequent Ga deposition/redesorption or N2-plasma cleaning step, a further reduction in oxygen and carbon could be achieved. In comparison, the Ga deposition/redesorption cleaning showed a better performance in oxygen removal, whereas the N2 plasma exhibits a better efficiency in carbon removal. Furthermore scanning tunneling microscopy and low-energy electron diffraction investigations showed a drastic improvement of the morphology and atomic structure of the clean surfaces in contrast to the sample surfaces after N2 storage and transfer.

  18. Cleaning of GaN(2110) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Ch.; Kuhr, S.; Geffers, H.; Schmidt, Th.; Flege, J. I.; Aschenbrenner, T.; Hommel, D.; Falta, J. [Institute of Solid State Physics, University Bremen, P.O. Box 330440, Bremen 28334 (Germany)

    2011-01-15

    The cleaning of GaN(2110) surfaces was investigated by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and low-energy electron diffraction. Two different two-step cleaning methods, performed under ultrahigh-vacuum conditions, were carried out and compared. The first cleaning step of both methods is thermal degassing. The second step is either the deposition of metallic gallium followed by redesorption or an exposure to active nitrogen from a radio frequency nitrogen plasma source. Upon storage in a glovebox (N{sub 2} atmosphere) and transfer to ultrahigh vacuum under dry nitrogen, carbon and oxygen were identified as the major contaminants. A significant decrease in oxygen and carbon was achieved by thermal degassing at 750 deg. C under ultrahigh-vacuum conditions. By applying a subsequent Ga deposition/redesorption or N{sub 2}-plasma cleaning step, a further reduction in oxygen and carbon could be achieved. In comparison, the Ga deposition/redesorption cleaning showed a better performance in oxygen removal, whereas the N{sub 2} plasma exhibits a better efficiency in carbon removal. Furthermore scanning tunneling microscopy and low-energy electron diffraction investigations showed a drastic improvement of the morphology and atomic structure of the clean surfaces in contrast to the sample surfaces after N{sub 2} storage and transfer.

  19. Transition to Clean Technology

    OpenAIRE

    Acemoglu, Daron; Akcigit, Ufuk; Hanley, Douglas; Kerr,William Robert

    2014-01-01

    We develop a microeconomic model of endogenous growth where clean and dirty technologies compete in production and innovation-in the sense that research can be directed to either clean or dirty technologies. If dirty technologies are more advanced to start with, the potential transition to clean technology can be difficult both because clean research must climb several steps to catch up with dirty technology and because this gap discourages research effort directed towards clean technologies....

  20. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen,and Zhejiang and Guangdong provinces to issue bonds for the first time.How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the Shanghai Securities Journal.Edited excerpts follow.

  1. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen, and Zhejiang and Guangdong provinces to issue bonds for the first time. How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the ShanghaiSecuritiesJournal. Edited excerpts follow:

  2. On Perfectly Clean Rings

    OpenAIRE

    Chen, H.; Halicioglu, S.; Kose, H.

    2013-01-01

    An element $a$ of a ring $R$ is called perfectly clean if there exists an idempotent $e\\in comm^2(a)$ such that $a-e\\in U(R)$. A ring $R$ is perfectly clean in case every element in $R$ is perfectly clean. In this paper, we investigate conditions on a local ring $R$ that imply that $2\\times 2$ matrix rings and triangular matrix rings are perfectly clean. We shall show that for these rings perfect cleanness and strong cleanness coincide with each other, and enhance many known results. We also ...

  3. Weak Nil Clean Rings

    OpenAIRE

    Basnet, Dhiren Kumar; Bhattacharyya, Jayanta

    2015-01-01

    We introduce the concept of a weak nil clean ring, a generalization of nil clean ring, which is nothing but a ring with unity in which every element can be expressed as sum or difference of a nilpotent and an idempotent. Further if the idempotent and nilpotent commute the ring is called weak* nil clean. We characterize all $n\\in \\mathbb{N}$, for which $\\mathbb{Z}_n$ is weak nil clean but not nil clean. We show that if $R$ is a weak* nil clean and $e$ is an idempotent in $R$, then the corner r...

  4. Clean Energy—The Ultimate Solution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Major economies in the world have raised various proposals to reduce carbon emissions by applying clean energies in a bid to tackle climate change. As a major consumer of coal, China is facing mounting pressure, and experts are wrangling about which clean energy should come first on the government agenda. To get a closer look at the current situation in China, Beijing Review reporter Liu Yunyun sat down with Zhou Dadi, Director General Emeritus of the Energy Research Institute of the National Development and Reform Commission, who shared his insights on clean energy. Edited excerpts follow:

  5. Distinguishing Bonds.

    Science.gov (United States)

    Rahm, Martin; Hoffmann, Roald

    2016-03-23

    The energy change per electron in a chemical or physical transformation, ΔE/n, may be expressed as Δχ̅ + Δ(VNN + ω)/n, where Δχ̅ is the average electron binding energy, a generalized electronegativity, ΔVNN is the change in nuclear repulsions, and Δω is the change in multielectron interactions in the process considered. The last term can be obtained by the difference from experimental or theoretical estimates of the first terms. Previously obtained consequences of this energy partitioning are extended here to a different analysis of bonding in a great variety of diatomics, including more or less polar ones. Arguments are presented for associating the average change in electron binding energy with covalence, and the change in multielectron interactions with electron transfer, either to, out, or within a molecule. A new descriptor Q, essentially the scaled difference between the Δχ̅ and Δ(VNN + ω)/n terms, when plotted versus the bond energy, separates nicely a wide variety of bonding types, covalent, covalent but more correlated, polar and increasingly ionic, metallogenic, electrostatic, charge-shift bonds, and dispersion interactions. Also, Q itself shows a set of interesting relations with the correlation energy of a bond. PMID:26910496

  6. Cleaning supplies and equipment

    Science.gov (United States)

    ... gov/ency/patientinstructions/000443.htm Cleaning supplies and equipment To use the sharing features on this page, ... to clean supplies and equipment. Disinfecting Supplies and Equipment Start by wearing the right personal protective equipment ( ...

  7. Factors Influencing Potential Acceptance and Adoption of Clean Development Mechanism Projects: Case of Carbon Trade Tree Project among Small Scale Farmers in Njoro District, Kenya

    OpenAIRE

    Oscar I. Ayuya; Job K. Lagat and John M. Mironga

    2011-01-01

    The aim of study was to assess the willingness of small scale farmers to accept and the extent of willingness to adopt carbon trade tree project and by so doing to identify and quantify factors that will influence adoption of carbon trade tree project. The study used multi-stage sampling procedure to select 150 small-scale farmers in Njoro district, Kenya. Both primary and secondary data sources collected using observations and interviews with the help of a semi-structured questionnaire. The ...

  8. Electron conjugation versus π-π repulsion in substituted benzenes: why the carbon-nitrogen bond in nitrobenzene is longer than in aniline.

    Science.gov (United States)

    Zhang, Huaiyu; Jiang, Xiaoyu; Wu, Wei; Mo, Yirong

    2016-04-28

    Gas-phase electron diffraction experiments show that the C-N bond in aniline (1.407 Å) is significantly shorter than in nitrobenzene (1.486 Å). It is known that the amino group is electron-donating and the nitro group is electron-withdrawing, and both substitution groups can effectively conjugate with benzene. Thus, it is puzzling why the C-N bond in nitrobenzene is even longer than the single C-N bond in methylamine (1.472 Å). In this work, we performed computations by strictly localizing the π electrons with the block-localized wavefunction (BLW) method, which is a variant of ab initio valence bond theory. Geometry optimizations of electron-localized states, where the conjugation over the C-N bond is quenched, show that the conjugation in nitrobenzene is only half of the conjugation in aniline. But even in optimal electron-localized states, the C-N bond in nitrobenzene is still 0.074 Å longer than in aniline. As a consequence, it is indeed not the π conjugation which is responsible for the disparity of the C-N bond distances in these systems. Instead, we demonstrated that the π-π repulsion, which is contributed by both Pauli exchange and electrostatic interaction, plays the key role in this "abnormal" behavior. Notably, the π resonance within the nitro group generates a considerable dipole, which repels the π electrons in the benzene ring. The deactivation of the resonance within the nitro group significantly shortens the C-N bond by 0.06 Å. The unfavorable π-π electrostatic repulsion is further exemplified by N2O4. In fact, the destabilizing π-π repulsion is ubiquitous but largely neglected in conjugated systems where only the stabilizing conjugation is the focus. Experimental phenomena such as the C-N bond distances in aniline and nitrobenzene result from the balance of both stabilizing and destabilizing forces. PMID:26852720

  9. Strength and leak testing of plasma activated bonded interfaces

    DEFF Research Database (Denmark)

    Visser, M.M.; Weichel, Steen; Reus, Roger De;

    2002-01-01

    Bond strength and hermeticity of plasma activated bonded (PAB) Si-Si interfaces are reported. Bonding of 100 mm Si(1 0 0) wafers was performed. An average bond strength of 9.0+/-3.9 MPa was achieved without performing any annealing steps. Cavities bonded in vacuum were found to be hermetic based on...... detection of changes in membrane deflections. The detection limit for leak was 8E-13 mbar l/s. For comparison, strength and leak tests were also performed with regular fusion bonded wafers annealed at 1100 degreesC. The PAB was found to withstand post-processing steps such as RCA cleaning, 24 h in de...

  10. Electromagnetically Clean Solar Arrays

    Science.gov (United States)

    Stem, Theodore G.; Kenniston, Anthony E.

    2008-01-01

    The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the

  11. Gas bubbling cleaning method

    International Nuclear Information System (INIS)

    The present invention concerns a gas bubbling cleaning method for objects to be cleaned having complicate shapes such as reactor equipments. For instance, air is used as the gas, while water is used as the cleaning fluid. A jetting air is jetted out to an object to be cleaned from an air bubbling nozzle disposed below the object. This constitutes air/water two phase flow near the object to be cleaned, to generate a three dimensional circulating flow. The distance between the inner wall surface of a cleaning vessel and the object to be cleaned is set to greater than 5 mm, and the ratio between the air flow rate and the horizontal cross section of the cleaning vessel is set to 0.1 to 0.4m/sec. This enables to enter an appropriate amount of bubbles to the air at the inside of the object to be cleaned having a complicate shape. Accordingly, deposits adhered to the inside of the object to be cleaned can be eliminated and cleaned effectively. (I.N.)

  12. Preperation for a Clean Surface

    OpenAIRE

    Aurimas Ralys; Valdemar Prokopovič; Vytautas Striška

    2013-01-01

    The article reviews techniques for preparing clean surfaces used in the manufacturing process, considers the types of clean surfaces and their role in modern production and provides the classification methods of arranging such surfaces. The paper also discusses the principles of methods for solvent cleaning, aqueous cleaning, ultrasonic cleaning, precision cleaning and mechanical cleaning. The study focuses on the possibility of adjusting a clean surface using a water flow, including cavitati...

  13. Preperation for a Clean Surface

    Directory of Open Access Journals (Sweden)

    Aurimas Ralys

    2012-12-01

    Full Text Available The article reviews techniques for preparing clean surfaces used in the manufacturing process, considers the types of clean surfaces and their role in modern production and provides the classification methods of arranging such surfaces. The paper also discusses the principles of methods for solvent cleaning, aqueous cleaning, ultrasonic cleaning, precision cleaning and mechanical cleaning. The study focuses on the possibility of adjusting a clean surface using a water flow, including cavitation.Article in Lithuanian

  14. Factors Influencing Potential Acceptance and Adoption of Clean Development Mechanism Projects: Case of Carbon Trade Tree Project among Small Scale Farmers in Njoro District, Kenya

    Directory of Open Access Journals (Sweden)

    Oscar I. Ayuya

    2011-04-01

    Full Text Available The aim of study was to assess the willingness of small scale farmers to accept and the extent of willingness to adopt carbon trade tree project and by so doing to identify and quantify factors that will influence adoption of carbon trade tree project. The study used multi-stage sampling procedure to select 150 small-scale farmers in Njoro district, Kenya. Both primary and secondary data sources collected using observations and interviews with the help of a semi-structured questionnaire. The double hurdle model was used identify the factors that influence the willingness to accept and the extent the farmers are willing to adopt the carbon tree trade project. Findings of the double hurdle model indicate that gender, household size, farm debt, attitude towards risk, farm size,land tenure, availability of voluntary CDM and perception of the technology were found to influence the willingness to accept the project. Further, age, extension contacts, attitude towards risk, land tenure and perception towards the technology influenced on the extent the farmer is willing to adopt. The study therefore, recommends policy interventions of improved training offarmers and extension officers on agroenvironmental programmes, formation of agro-environmental self-help groups by farmers and creation of strategies that would improve socio-economic conditions of smallholder farmers in Kenya.

  15. Diffusion bonding

    Science.gov (United States)

    Anderson, Robert C.

    1976-06-22

    1. A method for joining beryllium to beryllium by diffusion bonding, comprising the steps of coating at least one surface portion of at least two beryllium pieces with nickel, positioning a coated surface portion in a contiguous relationship with an other surface portion, subjecting the contiguously disposed surface portions to an environment having an atmosphere at a pressure lower than ambient pressure, applying a force upon the beryllium pieces for causing the contiguous surface portions to abut against each other, heating the contiguous surface portions to a maximum temperature less than the melting temperature of the beryllium, substantially uniformly decreasing the applied force while increasing the temperature after attaining a temperature substantially above room temperature, and maintaining a portion of the applied force at a temperature corresponding to about maximum temperature for a duration sufficient to effect the diffusion bond between the contiguous surface portions.

  16. Crystal Structures of Two Bacterial 3-Hydroxy-3-methylglutaryl-CoA Lyases Suggest a Common Catalytic Mechanism among a Family of TIM Barrel Metalloenzymes Cleaving Carbon-Carbon Bonds

    Energy Technology Data Exchange (ETDEWEB)

    Forouhar,F.; Hussain, M.; Farid, R.; Benach, J.; Abashidze, M.; Edstrom, W.; Vorobiev, S.; Montelione, G.; Hunt, J.; et al.

    2006-01-01

    The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase catalyzes the terminal steps in ketone body generation and leucine degradation. Mutations in this enzyme cause a human autosomal recessive disorder called primary metabolic aciduria, which typically kills victims because of an inability to tolerate hypoglycemia. Here we present crystal structures of the HMG-CoA lyases from Bacillus subtilis and Brucella melitensis at 2.7 and 2.3 {angstrom} resolution, respectively. These enzymes share greater than 45% sequence identity with the human orthologue. Although the enzyme has the anticipated triose-phosphate isomerase (TIM) barrel fold, the catalytic center contains a divalent cation-binding site formed by a cluster of invariant residues that cap the core of the barrel, contrary to the predictions of homology models. Surprisingly, the residues forming this cation-binding site and most of their interaction partners are shared with three other TIM barrel enzymes that catalyze diverse carbon-carbon bond cleavage reactions believed to proceed through enolate intermediates (4-hydroxy-2-ketovalerate aldolase, 2-isopropylmalate synthase, and transcarboxylase 5S). We propose the name 'DRE-TIM metallolyases' for this newly identified enzyme family likely to employ a common catalytic reaction mechanism involving an invariant Asp-Arg-Glu (DRE) triplet. The Asp ligates the divalent cation, while the Arg probably stabilizes charge accumulation in the enolate intermediate, and the Glu maintains the precise structural alignment of the Asp and Arg. We propose a detailed model for the catalytic reaction mechanism of HMG-CoA lyase based on the examination of previously reported product complexes of other DRE-TIM metallolyases and induced fit substrate docking studies conducted using the crystal structure of human HMG-CoA lyase (reported in the accompanying paper by Fu, et al. (2006) J. Biol. Chem. 281, 7526-7532). Our model is consistent with extensive mutagenesis

  17. Carbon and air pollutants constrained energy planning for clean power generation with a robust optimization model—A case study of Jining City, China

    International Nuclear Information System (INIS)

    Highlights: • Multistage inexact stochastic robust model for energy system management. • Electric power structure adjustment and emission reduction target are considered. • Power generation schemes, exported electricity, and captured CO2 were analyzed. • Uncertainties were reflected as discrete intervals and probability distributions. - Abstract: In this study, a multistage inexact stochastic robust model was developed for regional energy system management in Jining City, China. Three scenarios about the electric power structure adjustment, clean power generation, and the emission reduction target are designed. Methods of interval parameter programming (IPP), stochastic robust optimization (SRO), and multistage stochastic programming (MSP) were incorporated into the developed model to tackle uncertainties described by interval values and probability distributions. The results indicated that the model can provide an effective linkage between conflicting economic cost and the system stability, and different power demand levels correspond to different electricity generation schemes with varied system cost and system-failure risk. The net system cost, power generation schemes, exported electricity, and captured CO2 amount were analyzed. The results indicated that the power generation by traditional technology would be decreased with the improvement of regional energy structure adjustment and environmental protection request. The modeling results are valuable for supporting the adjustment or justification of the existing power generation schemes within a complicated energy system under uncertainty

  18. Clean Energy Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    For the past several years, the IEA and others have been calling for a clean energy revolution to achieve global energy security, economic growth and climate change goals. This report analyses for the first time progress in global clean energy technology deployment against the pathways that are needed to achieve these goals. It provides an overview of technology deployment status, key policy developments and public spending on RDD&D of clean energy technologies.

  19. Infrared steam laser cleaning

    OpenAIRE

    Frank, Pascal; Lang, Florian; Mosbacher, Mario; Boneberg, Johannes; Leiderer, Paul

    2008-01-01

    Steam Laser Cleaning with a pulsed infrared laser source is investigated. The infrared light is tuned to the absorption maximum of water (λ = 2.94 µm, 10 ns), whereas the substrates used are transparent (glass, silicon). Thus a thin liquid water layer condensed on top of the contaminated substrate is rapidly heated. The pressure generated during the subsequent phase explosion generates a cleaning force which exceeds the adhesion of the particles. We examine the cleaning threshold in single sh...

  20. Cleaning and surface properties

    CERN Document Server

    Taborelli, M

    2007-01-01

    Principles of precision cleaning for ultra high vacuum applications are reviewed together with the techniques for the evaluation of surface cleanliness. Methods to verify the effectiveness of cleaning procedures are discussed. Examples are presented to illustrate the influence of packaging and storage on the recontamination of the surface after cleaning. Finally, the effect of contamination on some relevant surface properties, like secondary electron emission and wettability is presented.

  1. Pi Bond Orders and Bond Lengths

    Science.gov (United States)

    Herndon, William C.; Parkanyi, Cyril

    1976-01-01

    Discusses three methods of correlating bond orders and bond lengths in unsaturated hydrocarbons: the Pauling theory, the Huckel molecular orbital technique, and self-consistent-field techniques. (MLH)

  2. Chemical cleaning, decontamination and corrosion

    International Nuclear Information System (INIS)

    Chemical cleaning of process equipments and pipings in chemical/petrochemical industries is necessitated for improving operation, for preventing premature failures and for avoiding contamination. In developing a chemical formulation for cleaning equipments, the important aspects to be considered include (i) effective removal of corrosion products and scales, (ii) minimum corrosion of the base metal, (iii) easy to handle chemicals and (iv) economic viability. As on date, a wide variety of chemical formulations are available, many of them are either proprietory or patented. For evolving an effective formulation, knowledge of the oxides of various metals and alloys on the one hand and acid concentration, complexing agents and inhibitors to be incorporated on the other, is quite essential. Organic acids like citric acid, acetic acid and formic acid are more popular ones, often used with EDTA for effective removal of corrosion products from ferrous components. The report enumerates some of the concepts in developing effective formulations for chemical cleaning of carbon steel components and further, makes an attempt to suggest simple formulations to be developed for chemical decontamination. (author). 6 refs., 3 fi gs., 4 tabs

  3. 40 CFR 35.936-22 - Bonding and insurance.

    Science.gov (United States)

    2010-07-01

    ... erection of treatment works or sewer system rehabilitation must furnish performance and payment bonds, each... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.936-22 Bonding and insurance. (a) On contracts for the building and erection of treatment works or contracts...

  4. On double bonds in fullerenes

    OpenAIRE

    Stepenshchikov D. G.; Voytekhovsky Yu. L.

    2016-01-01

    Various distributions of double carbon bonds in the fullerenes have been considered in the paper from the point that they are absent in the pentagonal rings. The appropriate classification of the fullerenes has been built. The results may be used when modeling the fullerenes of a given topology and calculating their physical-chemical properties

  5. Energy efficiency procedures for agricultural machinery used in onion cultivation (Allium fistulosum) as an alternative to reduce carbon emissions under the clean development mechanism at Aquitania (Colombia)

    International Nuclear Information System (INIS)

    Climate change has both causes and consequences over agriculture. This paper focuses on the first element and presents scenarios for ASOLAGO -an onion cropper's association in Colombia with 250 members- to reduce their carbon footprint. It evaluates a case study at ''La Primavera'' farm using a methodology approved by the United Nations Framework Convention on Climate Change. Land preparation and crop irrigation were analyzed as stages in order to propose energy efficiency alternatives for both the farm and the association. They include field efficiency, fuel economy and energy efficiency from biofuels for the first stage as well as solar and wind energy supply for the second. A cost-benefit analysis to generate additional income selling additional power produced by the system to the National Grid was done

  6. Energy efficiency procedures for agricultural machinery used in onion cultivation (Allium fistulosum) as an alternative to reduce carbon emissions under the clean development mechanism at Aquitania (Colombia)

    Science.gov (United States)

    Ochoa, K.; Carrillo, S.; Gutierrez, L.

    2014-06-01

    Climate change has both causes and consequences over agriculture. This paper focuses on the first element and presents scenarios for ASOLAGO -an onion cropper's association in Colombia with 250 members- to reduce their carbon footprint. It evaluates a case study at "La Primavera" farm using a methodology approved by the United Nations Framework Convention on Climate Change. Land preparation and crop irrigation were analyzed as stages in order to propose energy efficiency alternatives for both the farm and the association. They include field efficiency, fuel economy and energy efficiency from biofuels for the first stage as well as solar and wind energy supply for the second. A cost-benefit analysis to generate additional income selling additional power produced by the system to the National Grid was done.

  7. Role of active species in surface cleaning by an Ar-N2 atmospheric pressure post-discharge

    International Nuclear Information System (INIS)

    Post-discharge cleaning at atmospheric pressure of oxidized iron foils rinsed by acetone and methanol is studied by XPS. The influence of the temperature (T<450 K) and the UV photons on cleaning is negligible. When pure rare gases (He, Ne, Ar) are used, metastable species in post-discharge are transported downstream the plasma and relax their energy on the surface. C-C bonds are mainly removed by this process. When nitrogen is added to the rare gas (from 0 to 4.6 vol.% ), a selective influence on the etching process of the surface contaminants by nitrogen atoms is observed. The removal kinetics of chemical groups analysed by XPS is determined by using an exponential decay function corresponding to a first-order abstraction process. The decrease of C(1s) in N-C, O(1s) in N-C-O and N(1s) XPS peaks is correlated with the nitrogen atom concentration in the carrier gas. Reactions between nitrogen atoms and specific carbon containing groups occur (probably C-OH bonds of methanol). Stronger bonds like C=O (probably from acetone) are not removed by the post-discharge. (author)

  8. Silicon-Carbon Bond Formation via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Unactivated Secondary and Tertiary Alkyl Electrophiles.

    Science.gov (United States)

    Chu, Crystal K; Liang, Yufan; Fu, Gregory C

    2016-05-25

    A wide array of cross-coupling methods for the formation of C-C bonds from unactivated alkyl electrophiles have been described in recent years. In contrast, progress in the development of methods for the construction of C-heteroatom bonds has lagged; for example, there have been no reports of metal-catalyzed cross-couplings of unactivated secondary or tertiary alkyl halides with silicon nucleophiles to form C-Si bonds. In this study, we address this challenge, establishing that a simple, commercially available nickel catalyst (NiBr2·diglyme) can achieve couplings of alkyl bromides with nucleophilic silicon reagents under unusually mild conditions (e.g., -20 °C); especially noteworthy is our ability to employ unactivated tertiary alkyl halides as electrophilic coupling partners, which is still relatively uncommon in the field of cross-coupling chemistry. Stereochemical, relative reactivity, and radical-trap studies are consistent with a homolytic pathway for C-X bond cleavage. PMID:27187869

  9. Classes of almost clean rings

    OpenAIRE

    Akalan, Evrim; Vas, Lia

    2013-01-01

    A ring is clean (almost clean) if each of its elements is the sum of a unit (regular element) and an idempotent. A module is clean (almost clean) if its endomorphism ring is clean (almost clean). We show that every quasi-continuous and nonsingular module is almost clean and that every right CS and right nonsingular ring is almost clean. As a corollary, all right strongly semihereditary rings, including finite $AW^*$-algebras and noetherian Leavitt path algebras in particular, are almost clean...

  10. Laser surface cleaning

    International Nuclear Information System (INIS)

    The objective of this work is a laboratory demonstration that red-lead primer and two-part epoxy paints can be stripped from concrete and metal surfaces using surface cleaning systems based on pulsed-repetition CO2 lasers. The three goals are to: (1) demonstrate coatings removal, including surface pore cleaning; (2) demonstrate that there is negligible release of ablated contaminants to the environment; and (3) demonstrate that the process will generate negligible amounts of additional waste compared to competing technologies. Phase 1 involved site visits to RMI and Fernald to assess the cleaning issues for buildings and parts. In addition, Phase 1 included detailed designs of a more powerful system for industrial cleaning rates, including laser, articulating optics, ablated-material capture suction nozzle attached to a horizontal raster scanner for floor cleaning, and filtration system. Some concept development is also being done for using robots, and for parts cleaning. In Phase 2 a transportable 6 kW system will be built and tested, with a horizontal surface scanner for cleaning paint from floors. The laboratory tests will again be instrumented. Some concept development will continue for using robots, and for parts cleaning. This report describes Phase 1 results

  11. Green Cleaning Label Power

    Science.gov (United States)

    Balek, Bill

    2012-01-01

    Green cleaning plays a significant and supportive role in helping education institutions meet their sustainability goals. However, identifying cleaning products, supplies and equipment that truly are environmentally preferable can be daunting. The marketplace is inundated with products and services purporting to be "green" or environmentally…

  12. Clean Energy Manufacturing Initiative

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-04-01

    The initiative will strategically focus and rally EERE’s clean energy technology offices and Advanced Manufacturing Office around the urgent competitive opportunity for the United States to be the leader in the clean energy manufacturing industries and jobs of today and tomorrow.

  13. Nil-clean matrix rings

    OpenAIRE

    S. Breaz; Călugăreanu, G.; Danchev, P.; Micu, T.

    2013-01-01

    We characterize the nil clean matrix rings over fields. As a by product, it is proved that the full matrix rings with coefficients in commutative nil-clean rings are nil-clean, and we obtain a complete characterization of the finite rank Abelian groups with nil clean endomorphism ring and the Abelian groups with strongly nil clean endomorphism ring, respectively.

  14. The study on relation of clean grade rats deontal caries occurrence and carbonated drinks%碳酸饮料与清洁级大鼠龋齿发生相关性的实验研究

    Institute of Scientific and Technical Information of China (English)

    胡霞

    2016-01-01

    Objective The experimental study on compare the relation of different acidic drinks with rast dental caries.Methods 40 clean grade BABL/c rats were divided into deionized water group(groupA),Coca-Cola group (groupB),orange juice group(groupC)and Sprite group(groupD),10 rats each group,deionized watere group as control group,the other as the experimental group,using the classic Keyes score method to evaluate the occurrence of dental caries.Results Deionized water has the cariogenic effect on the enamel in the experimental group,carbonated drinks has acid effect on rat teeth,and can lead to dental caries.Conclusion Carbonated drinks have acid effect on enamel,and can lead to dental caries.%目的 比较不同的酸性饮料对清洁级大鼠龋齿发生率的影响.方法 将40只清洁级BABL/c鼠分为去离子水组(A组)、可口可乐组(B组)、鲜橙多组(C组)和雪碧组(D组),每组10只,去离子水组为对照组,其余为试验组,采用Keyes经典评分方法进行龋齿发生的评估.结果 除去离子水外其余实验饮料均对实验鼠的牙齿均有酸蚀作用,并可以导致龋齿.结论 碳酸饮料对牙釉质具有酸蚀作用,可以导致龋齿.

  15. Correlating Cleaning Thoroughness with Effectiveness and Briefly Intervening to Affect Cleaning Outcomes: How Clean Is Cleaned?

    Science.gov (United States)

    Hosford, Eve; Ong, Ana; Richesson, Douglas; Fraser, Susan; Kwak, Yoon; Miller, Sonia; Julius, Michael; McGann, Patrick; Lesho, Emil

    2016-01-01

    Objectives The most efficient approach to monitoring and improving cleaning outcomes remains unresolved. We sought to extend the findings of a previous study by determining whether cleaning thoroughness (dye removal) correlates with cleaning efficacy (absence of molecular or cultivable biomaterial) and whether one brief educational intervention improves cleaning outcomes. Design Before-after trial. Setting Newly built community hospital. Intervention 90 minute training refresher with surface-specific performance results. Methods Dye removal, measured by fluorescence, and biomaterial removal and acquisition, measured with culture and culture-independent PCR-based assays, were clandestinely assessed for eight consecutive months. At this midpoint, results were presented to the cleaning staff (intervention) and assessments continued for another eight consecutive months. Results 1273 surfaces were sampled before and after terminal room cleaning. In the short-term, dye removal increased from 40.3% to 50.0% (not significant). For the entire study period, dye removal also improved but not significantly. After the intervention, the number of rooms testing positive for specific pathogenic species by culturing decreased from 55.6% to 36.6% (not significant), and those testing positive by PCR fell from 80.6% to 53.7% (P = 0.016). For nonspecific biomaterial on surfaces: a) removal of cultivable Gram-negatives (GN) trended toward improvement (P = 0.056); b) removal of any cultivable growth was unchanged but acquisition (detection of biomaterial on post-cleaned surfaces that were contaminant-free before cleaning) worsened (P = 0.017); c) removal of PCR-based detection of bacterial DNA improved (P = 0.046), but acquisition worsened (P = 0.003); d) cleaning thoroughness and efficacy were not correlated. Conclusion At this facility, a minor intervention or minimally more aggressive cleaning may reduce pathogen-specific contamination, but not without unintended consequences. PMID

  16. Your First Stop for Clean Energy Policy Support (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-06-01

    The Clean Energy Solutions Center, an initiative of the Clean Energy Ministerial and UN-Energy, helps governments design and adopt policies and programs that support the deployment of transformational low-carbon technologies. The Solutions Center serves as a first-stop clearinghouse of clean energy policy reports, data, and tools and provides expert assistance and peer-to-peer learning forums. This factsheet highlights key Solutions Center offerings, including 'ask an expert' assistance on clean energy policy matters, training and peer learning, and technical resources for policy makers worldwide.

  17. Facile, green and clean one-step synthesis of carbon dots from wool: Application as a sensor for glyphosate detection based on the inner filter effect.

    Science.gov (United States)

    Wang, Long; Bi, Yidan; Hou, Juan; Li, Huiyu; Xu, Yuan; Wang, Bo; Ding, Hong; Ding, Lan

    2016-11-01

    In this work, we reported a green route for the fabrication of fluorescent carbon dots (CDs). Wool, a kind of nontoxic and natural raw material, was chosen as the precursor to prepare CDs via a one-step microwave-assisted pyrolysis process. Compared with previously reported methods for preparation of CDs based on biomass materials, this method was simple, facile and free of any additives, such as acids, bases, or salts, which avoid the complicated post-treatment process to purify the CDs. The CDs have a high quantum yield (16.3%) and their fluorescence could be quenched by silver nanoparticles (AgNPs) based on inner filter effect (IFE). The presence of glyphosate could induce the aggregation of AgNPs and thus result in the fluorescence recovery of the quenched CDs. Based on this phenomenon, we constructed a fluorescence system (CDs/AgNPs) for determination of glyphosate. Under the optimized conditions, the fluorescence intensity of the CDs/AgNPs system was proportional to the concentration of glyphosate in the range of 0.025-2.5μgmL(-1), with a detection limit of 12ngmL(-1). Furthermore, the established method has been successfully used for glyphosate detection in the cereal samples with satisfactory results. PMID:27591613

  18. CO2 (dry ice) cleaning system

    Science.gov (United States)

    Barnett, Donald M.

    1995-01-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  19. Discharge cleaning on TFTR after boronization

    International Nuclear Information System (INIS)

    At the beginning of the 1990 TFTR experimental run, after replacement of POCO-AXF-5Q graphite tiles on the midplane of the bumper limiter by carbon fiber composite (CFC) tiles and prior to any Pulse Discharge Cleaning (PDC), boronization was performed. Boronization is the deposition of a layer of boron and carbon on the vacuum vessel inner surface by a glow discharge in a diborane, methane and helium mixture. The amount of discharge cleaning required after boronization was substantially reduced compared to that which was needed after previous openings when boronization was not done. Previously, after a major shutdown, about 105 low current (∼20 kA) Taylor Discharge Cleaning (TDC) pulses were required before high current (∼400 kA) aggressive Pulse Discharge Cleaning (PDC) pulses could be performed successfully. Aggressive PDC is used to heat the limiters from the vessel bakeout temperature of 150 degrees C to 250 degrees C for a period of several hours. Heating the limiters is important to increase the rate at which water is removed from the carbon limiter tiles. After boronization, the number of required TDC pulses was reduced to <5000. The number of aggressive PDC pulses required was approximately unchanged. 14 refs., 1 tab

  20. Cleaning techniques for intense ion beam sources

    International Nuclear Information System (INIS)

    Generation of high power lithium ion beams on the SABRE (1TW) and PBFA-X (20 TW) accelerators have been limited by the parallel acceleration of contaminant ions. during the beam pulse lithium is replaced by protons and carbon ions. This replacement is accompanied by rapid impedance decay of the diode. The contaminant hydrogen and carbon is believed to originate from impurity molecules on the surface and in the bulk of the lithium ion source and its substrate material. Cleaning techniques designed to remove hydrocarbons from the ion source have been employed with some success in test stand experiments and on SABRE. The test stand experiments have shown that a lithium fluoride (LiF) ion source film can accrue dozens of hydrocarbon monolayers on its surface while sitting in vacuum. Application of 13.5 MHz RF discharge cleaning with 90% Ar/10% O2 can significantly reduce the surface hydrocarbon layers on the LiF film. On SABRE, combinations of RF discharge cleaning, anode heating, layering gold between the source film (LiF) and its substrate, and cryogenic cathode cooling produced an increase by a factor of 1.5--2 in the quantity of high energy lithium in the ion beam. A corresponding decrease in protons and carbon ions was also observed. Cleaning experiments on PBFA-X are underway. New designs of contamination resistant films and Li ion sources are currently being investigated

  1. Cleaning and can end chamfering special machine MSCS-04

    International Nuclear Information System (INIS)

    The MSCS-04 machine executes cleaning and can end chamfering of the CANDU 6 fuel element can through the following technologic chain: - manual positioning of the workpiece in the transporter feeding location; - the transport of the workpiece in front of the cleaning machine and workpiece orientation checking; - automatic loading of the workpiece in the cleaning machine; - bonding the workpiece in the cleaning machine; - cleaning the ends of the workpiece with graphite dust aspiration; - automatic disconnection of the workpiece from the cleaning machine; - automatic unloading of the cleaning machine; - disposal of the workpiece on the transporter in front of cleaning machine; workpiece's transport in front of the chamfering machine; - automatic checking of the workpiece orientation; - automatic loading of the workpiece in the chamfering machine; - axial positioning and bounding of the workpiece in the chamfering machine; chamfering the workpiece's ends with graphite dust and splinter aspiration; - disconnecting the workpiece from the chamfering machine; - automatic unloading of the workpiece from the chamfering machine with splinter blow from the workpiece interior; - workpiece disposal on transporter and the piece transport to the outlet. Details about the technological system, transport system, manipulators, cleaning and chamfering machines are given. Novel elements are highlighted and the technical characteristics are presented

  2. Natural arsenic attenuation via metal arsenate precipitation in soils contaminated with metallurgical wastes: III. Adsorption versus precipitation in clean As(V)/goethite/Pb(II)/carbonate systems

    International Nuclear Information System (INIS)

    Soil contamination with As and potentially harmful metals is a widespread problem around the world especially from mining and metallurgical wastes, which release substantial amounts of these elements to the environment in potentially mobile species. Recently, it has been found that in various Mexican soils contaminated with these types of wastes, arsenate is not in the form of sorbed species on Fe oxides present in the soils, as generally reported in the literature, but in the form of very insoluble compounds such as Pb, Cu and Ca arsenates. Here a thermodynamic model is applied and validated with the results from wet chemical experiments to determine the fundamental geochemical conditions governing the mobility of As in the presence of Pb. For this purpose, a relatively simple but fundamental system of goethite (α-FeOOH)/As(V)/Pb(II)/carbonate was defined as a function of the As(V)/Fe(III) ratio, in a pH range of 5–10. The speciation model included the simultaneous inclusion of triple layer surface complexation and arsenate precipitation equilibria. The model predicts that from very low total As(V)/Fe(III) molar ratios (0.012 at pH 7) the precipitation mechanism significantly influences the attenuation of As(V), and rapidly becomes the dominant process over the adsorption mechanism. Model results identify the quantitative conditions of predominance for each mechanism and describe the transition conditions in which relatively large fractions of adsorbed, precipitated and dissolved As(V) species prevail. Experimental measurements at selected As(V)/Fe(III) ratios and pH confirmed the predictions and validated the coupled thermodynamic model utilized.

  3. Fluid dynamic effects on precision cleaning with supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.R.; Hogan, M.O.; Silva, L.J.

    1994-06-01

    Pacific Northwest Laboratory staff have assembled a small supercritical fluids parts cleaning test stand to characterize how system dynamics affect the efficacy of precision cleaning with supercritical carbon dioxide. A soiled stainless steel coupon, loaded into a ``Berty`` autoclave, was used to investigate how changes in system turbulence and solvent temperature influenced the removal of test dopants. A pulsed laser beam through a fiber optic was used to investigate real-time contaminant removal. Test data show that cleaning efficiency is a function of system agitation, solvent density, and temperature. These data also show that high levels of cleaning efficiency can generally be achieved with high levels of system agitation at relatively low solvent densities and temperatures. Agitation levels, temperatures, and densities needed for optimal cleaning are largely contaminant dependent. Using proper system conditions, the levels of cleanliness achieved with supercritical carbon dioxide compare favorably with conventional precision cleaning methods. Additional research is currently being conducted to generalize the relationship between cleaning performance and parameters such as contaminant solubilities, mass transfer rates, and solvent agitation. These correlations can be used to optimize cleaning performance, system design, and time and energy consumption for particular parts cleaning applications.

  4. Clean coal technologies

    International Nuclear Information System (INIS)

    According to the World Energy Council (WEC), at the beginning of the next century three main energy sources - coal, nuclear power and oil will have equal share in the world's total energy supply. This forecast is also valid for the USSR which possesses more than 40% of the world's coal resources and continuously increases its coal production (more than 700 million tons of coal are processed annually in the USSR). The stringent environmental regulations, coupled with the tendency to increase the use of coal are the reasons for developing different concepts for clean coal utilization. In this paper, the potential efficiency and environmental performance of different clean coal production cycles are considered, including technologies for coal clean-up at the pre-combustion stage, advanced clean combustion methods and flue gas cleaning systems. Integrated systems, such as combined gas-steam cycle and the pressurized fluidized bed boiler combined cycle, are also discussed. The Soviet National R and D program is studying new methods for coal utilization with high environmental performance. In this context, some basic research activities in the field of clean coal technology in the USSR are considered. Development of an efficient vortex combustor, a pressurized fluidized bed gasifier, advanced gas cleaning methods based on E-beam irradiation and plasma discharge, as well as new catalytic system, are are presented. In addition, implementation of technological innovations for retrofitting and re powering of existing power plants is discussed. (author)

  5. Wind power projects in the CDM: Methodologies and tools for baselines, carbon financing and substainability analysis[CDM=Clean Development Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ringius, L.; Grohnheit, P.E.; Nielsen, L.H.; Olivier, A.L.; Painuly, J.; Villavicencio, A.

    2002-12-01

    The report is intended to be a guidance document for project developers, investors, lenders, and CDM host countries involved in wind power projects in the CDM. The report explores in particular those issues that are important in CDM project assessment and development - that is, baseline development, carbon financing, and environmental sustainability. It does not deal in detail with those issues that are routinely covered in a standard wind power project assessment. The report tests, compares, and recommends methodologies for and approaches to baseline development. To present the application and implications of the various methodologies and approaches in a concrete context, Africa's largest wind farm-namely the 60 MW wind farm located in Zafarana, Egypt- is examined as a hypothetical CDM wind power project The report shows that for the present case example there is a difference of about 25% between the lowest (0.5496 tCO2/MWh) and the highest emission rate (0.6868 tCO{sub 2}/MWh) estimated in accordance with these three standardized approaches to baseline development according to the Marrakesh Accord. This difference in emission factors comes about partly as a result of including hydroelectric power in the baseline scenario. Hydroelectric resources constitute around 21% of the generation capacity in Egypt, and, if excluding hydropower, the difference between the lowest and the highest baseline is reduced to 18%. Furthermore, since the two variations of the 'historical' baseline option examined result in the highest and the lowest baselines, by disregarding this baseline option altogether the difference between the lowest and the highest is reduced to 16%. The ES3-model, which the Systems Analysis Department at Risoe National Laboratory has developed, makes it possible for this report to explore the project-specific approach to baseline development in some detail. Based on quite disaggregated data on the Egyptian electricity system, including the wind

  6. Generalization of Strongly Clean Rings

    OpenAIRE

    Singh, Abhay K.

    2012-01-01

    In this paper, strongly clean ring defined by W. K. Nicholson in 1999 has been generalized to n-strongly clean, {\\Sigma}-strongly clean and with the help of example it has been shown that there exists a ring, which is n-strongly clean and {\\Sigma}-strongly clean but not strongly clean. It has been shown that for a commutative ring R formal power series R[(x)] of R is n-strongly clean if and only if R is n- strongly clean. We also discussed the structure of homomorphic image of n- strongly cle...

  7. Air Cleaning Technologies

    Science.gov (United States)

    2005-01-01

    Executive Summary Objective This health technology policy assessment will answer the following questions: When should in-room air cleaners be used? How effective are in-room air cleaners? Are in-room air cleaners that use combined HEPA and UVGI air cleaning technology more effective than those that use HEPA filtration alone? What is the Plasmacluster ion air purifier in the pandemic influenza preparation plan? The experience of severe acute respiratory syndrome (SARS) locally, nationally, and internationally underscored the importance of administrative, environmental, and personal protective infection control measures in health care facilities. In the aftermath of the SARS crisis, there was a need for a clearer understanding of Ontario’s capacity to manage suspected or confirmed cases of airborne infectious diseases. In so doing, the Walker Commission thought that more attention should be paid to the potential use of new technologies such as in-room air cleaning units. It recommended that the Medical Advisory Secretariat of the Ontario Ministry of Health and Long-Term Care evaluate the appropriate use and effectiveness of such new technologies. Accordingly, the Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat to review the literature on the effectiveness and utility of in-room air cleaners that use high-efficiency particle air (HEPA) filters and ultraviolet germicidal irradiation (UVGI) air cleaning technology. Additionally, the Ontario Health Technology Advisory Committee prioritized a request from the ministry’s Emergency Management Unit to investigate the possible role of the Plasmacluster ion air purifier manufactured by Sharp Electronics Corporation, in the pandemic influenza preparation plan. Clinical Need Airborne transmission of infectious diseases depends in part on the concentration of breathable infectious pathogens (germs) in room air. Infection control is achieved by a combination of administrative, engineering

  8. Clean Water Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into U.S. waters and regulating quality standards for surface...

  9. Nuclear air cleaning

    International Nuclear Information System (INIS)

    This report briefly describes the history of the use of high- efficiency particulate air filters for air cleaning at nuclear installations in the United States and discusses future uses of such filters

  10. FINAL TECHNICAL REPORT for grant DE-FG02-93ER14353 "Carbon-Hydrogen Bond Functionalization Catalyzed by Transition Metal Systems"

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Alan S

    2012-05-21

    Alkanes are our most abundant organic resource but are highly resistant to selective chemical transformations. Alkenes (olefins) by contrast are the single most versatile class of molecules for selective transformations, and are intermediates in virtually every petrochemical process as well as a vast range of commodity and fine chemical processes. Over the course of this project we have developed the most efficient catalysts to date for the selective conversion of alkanes to give olefins, and have applied these catalysts to other dehydrogenation reactions. We have also developed some of the first efficient catalysts for carbonylation of alkanes and arenes to give aldehydes. The development of these catalysts has been accompanied by elucidation of the mechanism of their operation and the factors controlling the kinetics and thermodynamics of C-H bond activation and other individual steps of the catalytic cycles. This fundamental understanding will allow the further improvement of these catalysts, as well as the development of the next generation of catalysts for the functionalization of alkanes and other molecules containing C-H bonds.

  11. Redox Activation of Dicarbonyl (.eta.5-Cyclopentadienyl) Methyl Iron within the Cavity of .beta.-Cyclodextrin: Carbon Monoxide Insertion in Iron -Methyl Bond

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Hromadová, Magdaléna; Fiedler, Jan; Amatore, C.; Verpeaux, J. N.

    COST, 2004. s. 6. [Workshop on Interfacial Chemistry and Catalysis /4./. 20.10.2004-22.10.2004, La Cole sur Loup] R&D Projects: GA MŠk 1P04OCD15.10 Keywords : dicarbonyl * iron-methyl * carbon Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Clean Coal Program Research Activities

    Energy Technology Data Exchange (ETDEWEB)

    Larry Baxter; Eric Eddings; Thomas Fletcher; Kerry Kelly; JoAnn Lighty; Ronald Pugmire; Adel Sarofim; Geoffrey Silcox; Phillip Smith; Jeremy Thornock; Jost Wendt; Kevin Whitty

    2009-03-31

    Although remarkable progress has been made in developing technologies for the clean and efficient utilization of coal, the biggest challenge in the utilization of coal is still the protection of the environment. Specifically, electric utilities face increasingly stringent restriction on the emissions of NO{sub x} and SO{sub x}, new mercury emission standards, and mounting pressure for the mitigation of CO{sub 2} emissions, an environmental challenge that is greater than any they have previously faced. The Utah Clean Coal Program addressed issues related to innovations for existing power plants including retrofit technologies for carbon capture and sequestration (CCS) or green field plants with CCS. The Program focused on the following areas: simulation, mercury control, oxycoal combustion, gasification, sequestration, chemical looping combustion, materials investigations and student research experiences. The goal of this program was to begin to integrate the experimental and simulation activities and to partner with NETL researchers to integrate the Program's results with those at NETL, using simulation as the vehicle for integration and innovation. The investigators also committed to training students in coal utilization technology tuned to the environmental constraints that we face in the future; to this end the Program supported approximately 12 graduate students toward the completion of their graduate degree in addition to numerous undergraduate students. With the increased importance of coal for energy independence, training of graduate and undergraduate students in the development of new technologies is critical.

  13. Clean Elements in Abelian Rings

    Indian Academy of Sciences (India)

    Angelina Y M Chin

    2009-04-01

    Let be a ring with identity. An element in is said to be clean if it is the sum of a unit and an idempotent. is said to be clean if all of its elements are clean. If every idempotent in is central, then is said to be abelian. In this paper we obtain some conditions equivalent to being clean in an abelian ring.

  14. Northwest Region Clean Energy Application Center

    Energy Technology Data Exchange (ETDEWEB)

    Sjoding, David

    2013-09-30

    The main objective of the Northwest Clean Energy Application Center (NW CEAC) is to promote and support implementation of clean energy technologies. These technologies include combined heat and power (CHP), district energy, waste heat recovery with a primary focus on waste heat to power, and other related clean energy systems such as stationary fuel cell CHP systems. The northwest states include AK, ID, MT, OR, and WA. The key aim/outcome of the Center is to promote and support implementation of clean energy projects. Implemented projects result in a number of benefits including increased energy efficiency, renewable energy development (when using opportunity fuels), reduced carbon emissions, improved facility economics helping to preserve jobs, and reduced criteria pollutants calculated on an output-based emissions basis. Specific objectives performed by the NW CEAC fall within the following five broad promotion and support categories: 1) Center management and planning including database support; 2) Education and Outreach including plan development, website, target market workshops, and education/outreach materials development 3) Identification and provision of screening assessments & feasibility studies as funded by the facility or occasionally further support of Potential High Impact Projects; 4) Project implementation assistance/trouble shooting; and 5) Development of a supportive clean energy policy and initiative/financing framework.

  15. Is dry cleaning all wet?

    International Nuclear Information System (INIS)

    Chemical solvents from dry cleaning, particularly perchloroethylene (perc), have contributed to groundwater contamination, significant levels of air pollution in and around cleaners, and chemical accumulation in food. Questions are being raised about the process of cleaning clothes with chemical, and other less toxic cleaning methods are being explored. The EPA has focused attention on the 50 year old Friedburg method of cleaning, Ecoclean, which uses no dangerous chemicals and achieves comparable results. Unfortunately, the cleaning industry is resistant to change, so cutting back on amount of clothes that need dry cleaning and making sure labels aren't exaggerating when they say dry clean only, is frequently the only consumer option now

  16. Constraints on the factors controlling 13C-18O bond abundances in biologically precipitated carbonates from measurements of marine calcifiers cultured at variable temperature, pH, and salinity

    Science.gov (United States)

    Conchas, T. E.; Eagle, R.; Eiler, J. M.; Ries, J. B.; Freitas, P. S.; Hiebenthal, C.; Wanamaker, A. D.; Tripati, A. K.

    2012-12-01

    Marine mollusks and corals are widely used as archives of past climate change; oxygen isotopic composition (δ18O value) of their carbonate minerals is perhaps the most commonly used proxy to reconstruct paleoclimate from these marine calcifiers. However, oxygen isotope paleothermometry of mollusks and corals is complicated by non-equilibrium "vital effects" and variations in seawater pH changes, both of which influence the net fractionation of oxygen isotopes between carbonate and water. Carbonate "clumped isotope" thermometry is an emerging approach that potentially addresses these ambiguities. Here we report measurements of abundance of 13C-18O bonds (described by the measured parameter Δ47) in a variety of marine calcifiers cultured under controlled conditions. Previous studies on biologically precipitated samples such as foraminifera, coccoliths, and corals have shown that Δ47 values are related to calcification temperature with a relationship that is generally similar to inorganic carbonate. However, the influence of effects other than temperature has not been extensively studied and little work has been done to explore the potential for small non-equilibrium effects in cultured specimens that were grown under controlled conditions. In this study, we report δ18O and Δ47 measurements of mollusk specimens that were cultured at several temperatures ranging from 5 to 25°C, as well as different pH and salinity values. We also report data for other marine calcifiers including the temperate coral species Oculina arbuscula and the coralline red algae Neogoniolithon sp., that were cultured at a single temperature but variable pH.

  17. Ductless personalized ventilation with local air cleaning

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Vesely, Michal; Melikov, Arsen Krikor

    2012-01-01

    An experiment with 28 human subjects was performed to examine effects of using a local air cleaning device combined with ductless personalized ventilation (DPV) on perceived air quality. Experiments were performed in a test room with displacement ventilation. The DPV at one of two desks was...... equipped with an activated carbon filter installed at the air intake, while the DPV at the second desk was without such a filter. The air temperature in the occupied zone (1.1 m above the floor) was 29 °C. The pollution load in the room was simulated by PVC floor covering. The subjects assessed...... acceptability of air quality, odour intensity and air freshness at both desks in random order. Lower odour intensity and higher air freshness was reported at the desk with DPV with the activated carbon filter. The results suggest that using local air cleaning devices integrated with DPV may improve perceived...

  18. Cross Shear Roll Bonding

    DEFF Research Database (Denmark)

    Bay, Niels; Bjerregaard, Henrik; Petersen, Søren. B;

    1994-01-01

    The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20......-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results....

  19. Laser cleaning of Rakowicze sandstone

    OpenAIRE

    Nijland, T.G.; Wijffels, T.J.

    2003-01-01

    Decisions about the cleaning of natural stone should always be made within the awareness of direct and indirect damage that may be the result of cleaning. During the last decade, laser cleaning of objects and monuments of natural stone has become increasingly popular. Whereas a considerable amount of literature has been devoted to the effect of laser cleaning on marble and limestone, research into the effects on sandstone is limited. In the present paper, the effect of two cleaning methods, v...

  20. LensClean revisited

    CERN Document Server

    Wucknitz, O

    2004-01-01

    We discuss the LensClean algorithm which for a given gravitational lens model fits a source brightness distribution to interferometric radio data in a similar way as standard Clean does in the unlensed case. The lens model parameters can then be varied in order to minimize the residuals and determine the best model for the lens mass distribution. Our variant of this method is improved in order to be useful and stable even for high dynamic range systems with nearly degenerated lens model parameters. Our test case B0218+357 is dominated by two bright images but the information needed to constrain the unknown parameters is provided only by the relatively smooth and weak Einstein ring. The new variant of LensClean is able to fit lens models even in this difficult case. In order to allow the use of general mass models with LensClean, we develop the new method LenTil which inverts the lens equation much more reliably than any other method. This high reliability is essential for the use as part of LensClean. Finally...

  1. N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd–NHC complexes: synthesis, characterization and catalytic activity in carbon–carbon bond-forming reactions

    Science.gov (United States)

    Gök, Yetkin; İlhan, İlhan Özer

    2016-01-01

    Summary A series of novel benzimidazolium salts (1–4) and their pyridine enhanced precatalyst preparation stabilization and initiation (PEPPSI) themed palladium N-heterocyclic carbene complexes [PdCl2(NHC)(Py)] (5–8), where NHC = 1-(N-methylphthalimide)-3-alkylbenzimidazolin-2-ylidene and Py = 3-chloropyridine, were synthesized and characterized by means of 1H and 13C{1H} NMR, UV–vis (for 5–8), ESI-FTICR-MS (for 2, 4, 6–8) and FTIR spectroscopic methods and elemental analysis. The synthesized compounds were tested in Suzuki–Miyaura cross-coupling (for 1–8) and arylation (for 5–8) reactions. As catalysts, they demonstrated a highly efficient route for the formation of asymmetric biaryl compounds even though they were used in very low loading. For example, all compounds displayed good catalytic activity for the C–C bond formation of 4-tert-butylphenylboronic acid with 4-chlorotoluene. PMID:26877810

  2. Cleaning verification by air/water impingement

    Science.gov (United States)

    Jones, Lisa L.; Littlefield, Maria D.; Melton, Gregory S.; Caimi, Raoul E. B.; Thaxton, Eric A.

    1995-01-01

    This paper will discuss how the Kennedy Space Center intends to perform precision cleaning verification by Air/Water Impingement in lieu of chlorofluorocarbon-113 gravimetric nonvolatile residue analysis (NVR). Test results will be given that demonstrate the effectiveness of the Air/Water system. A brief discussion of the Total Carbon method via the use of a high temperature combustion analyzer will also be given. The necessary equipment for impingement will be shown along with other possible applications of this technology.

  3. Characterization of Metallically Bonded Carbon Nanotube-Based Thermal Interface Materials Using a High Accuracy 1D Steady-State Technique

    OpenAIRE

    Wasniewski, Joseph R.; Altman, David H.; Stephen L. Hodson; Fisher, Timothy S.; Bulusu, Anuradha; Graham, Samuel; Cola, Baratunde A.

    2012-01-01

    The next generation of thermal interface materials (TIMs) are currently being developed to meet the increasing demands of high-powered semiconductor devices. In particular, a variety of nanostructured materials, such as carbon nanotubes (CNTs), are interesting due to their ability to provide low resistance heat transport from device-to-spreader and compliance between materials with dissimilar coefficients of thermal expansion (CTEs), but few application-ready configurations have been produced...

  4. FORMATION OF C-I COVALENT BOND BETWEEN THE SINGLE-WALL CARBON NANOTUBES AND SODIUM IODIDE%单壁碳纳米管与碘化钠形成C-I共价键

    Institute of Scientific and Technical Information of China (English)

    黄洁华; 林治卿; 刘丽华; 刘焕亮; 胡传禄; 程文文; 袭著革

    2011-01-01

    目的 探讨单壁碳纳米管与碘化钠反应后C-I共价键的生成及其表征,为单壁碳纳米管放射性碘标记及观察其在生物体内分布提供实验参考数据.方法 采用1odogen方法制备碘化的单壁碳纳米管(I-SWCNTs),然后用透射电子显微镜(TEM)及X射线光电子能谱仪(XPS)对碳碘结合及C-I共价键的形成进行表征.结果 TEM成像和成分分析显示,与未经处理的SWCNTs 对比,处理后的产物其管壁不再光滑,有缺口,其上结合有碘.XPS检测发现,碘与SWCNTs形成C-I共价键,处理后产物的碘电子结合能与具有C-I共价键的参考物硝基碘苯基本一致,而与具有离子性质的NaI的结合能不同.结论 用Iodogen法能使SWCNTs与NaI结合生成C-I共价键.%Objective To explore the formation and characterization of C-I covalent bond between the singlewall carbon nanotubes (SWCNTs) and NaI in order to provide experimental reference data for radioiodination of SWCNTs and oberving its biodistribution. Methods IMogen method was used to synthesize iodinated SWCNTs (I-SWCNTs) in which iodine was covalently bound to SWCNTs. The formation of C-I bond was proved by transmission electron microscope(TEM) as well as X-ray photoelectron spectroscopy (XPS) . Results The image and component analyses TEM showed that the wall of the tubes of I-SWCNTs became rough, with gaps, and bound iodine, as compared to that of the tmtreated products. XPS spectra showed that the binding energy of iodine of I-SWCNTs was analogous to that of nitroiodobenzene and different from that of ionic NaI. Conclusion The C-I covalent bond between the single-wall carbon nanotubes and NaI could be formed by the Iodogen method.

  5. The Clean Air Act

    International Nuclear Information System (INIS)

    The Clean Air Act amendments alter the complex laws affecting atmospheric pollution and at the same time have broad implications for energy. Specifically, the Clean Air Act amendments for the first time deal with the environmental problem of acid deposition in a way that minimizes energy and economic impacts. By relying upon a market-based system of emission trading, a least cost solution will be used to reduce sulfur dioxide (SO2) emissions by almost 40 percent. The emission trading system is the centerpiece of the Clean Air Act (CAA) amendments effort to resolve energy and environmental interactions in a manner that will maximize environmental solutions while minimizing energy impacts. This paper will explore how the present CAA amendments deal with the emission trading system and the likely impact of the emission trading system and the CAA amendments upon the electric power industry

  6. Bond order potentials for fracture, wear, and plasticity

    OpenAIRE

    Pastewka, L.; Mrovec, M.; Moseler, M.; Gumbsch, P.

    2012-01-01

    Coulson's bond order is a chemically intuitive quantity that measures the difference in the occupation of bonding and anti-bonding orbitals. Both empirical and rigorously derived bond order expressions have evolved in the course of time and proven very useful for atomistic modeling of materials. The latest generation of empirical formulations has recently been augmented by screening-function approaches. Using friction and wear of diamond and diamond-like carbon as examples, we demonstrate tha...

  7. On f-clean rings and f-clean elements

    OpenAIRE

    Ali H. Handam

    2011-01-01

    An associative ring R with identity is called f -clean ring if every element in R is the sum of an idempotent and a full element. In this paper, various basic properties of f -clean rings and f -clean elements are proved. Also, we give some new charaterizations of f -clean rings. In addition, we prove that the ring of skew Hurwitz series T = (HR, σ) where σ is an automorphism of R is f -clean if and only if R is f -clean.

  8. CLEANING OF FRENCH SITES

    CERN Document Server

    Mauro Nonis

    2002-01-01

    In the last two weeks some cleaning problems have been remarked in several CERN buildings on the French part of CERN sites. This is mainly due to the start up of the new cleaning contract from the 1st July. These problems are not related to a budgetary reduction of the activity. We excuse for the malfunctions that have been created to CERN community and we assure you that we have taken all the needed measures to solve the problem in the shortest delay. Mauro Nonis (ST/FM)

  9. How to bond to root canal dentin

    Science.gov (United States)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  10. On Bond Portfolio Management

    OpenAIRE

    Vladislav Kargin

    2002-01-01

    This paper describes a new method of bond portfolio optimization based on stochastic string models of correlation structure in bond returns. The paper shows how to approximate correlation function of bond returns, compute the optimal portfolio allocation using Wiener-Hopf factorization, and check whether a collection of bonds presents arbitrage opportunities.

  11. Acyl-Carbon Bond Cleaving Cytochrome P450 Enzymes: CYP17A1, CYP19A1 and CYP51A1.

    Science.gov (United States)

    Akhtar, Muhammad; Wright, J Neville

    2015-01-01

    Cytochrome P450 (P450 or CYP) enzymes in their resting state contain the heme-iron in a high-spin FeIII state. Binding of a substrate to a P450 enzyme allows transfer of the first electron, producing a Fe(II) species that reacts with oxygen to generate a low-spin iron superoxide intermediate (FeIII-O-O•) ready to accept the second electron to produce an iron peroxy anion intermediate (a, FeIII-O-O-). In classical monooxygenation reactions, the peroxy anion upon protonation fragments to form the reactive Compound I intermediate (Por•+FeIV=O), or its ferryl radical resonance form (FeIV-O•). However, when the substrate projects a carbonyl functionality, of the type b, at the active site as is the case for reactions catalyzed by CYP17A1, CYP19A1 and CYP51A1, the peroxy anion (FeIII-O-O-) is trapped, yielding a tetrahedral intermediate (c) that fragments to an acyl-carbon cleavage product (d plus an acid). Analogous acyl-carbon cleavage reactions are also catalyzed by certain hepatic P450s and CYP125A1 from Mycobacterium tuberculosis. A further improvisation on the theme is provided by aldehyde deformylases that convert long-chain aliphatic aldehydes to hydrocarbons. CYP17A1 is involved in the biosynthesis of corticoids as well as androgens. The flux toward these two classes of hormones seems to be regulated by cytochrome b 5, at the level of the acyl-carbon cleavage reaction. It is this regulation of CYP17A1 that provides a safety mechanism, ensuring that during corticoid biosynthesis, which requires 17α-hydroxylation by CYP17A1, androgen formation is avoided (Fig. 4.1). PMID:26002733

  12. 16th DOE nuclear air cleaning conference: proceedings

    International Nuclear Information System (INIS)

    Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas: treatment of offgases from chemical processing; aerosol; behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions; HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration; filter testing; and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

  13. 16th DOE nuclear air cleaning conference: proceedings

    International Nuclear Information System (INIS)

    Major topics discussed during the Sixteenth DOE Nuclear Air Cleaning Conference were: waste treatment, including volume reduction and storage; system and component response to stress and accident conditions; Three Mile Island accident; iodine adsorption; treatment and storage of noble gas; treatment of offgases from chemical processing; aerosol behavior; containment venting; laboratory and in-place filter-testing methods; and particulate filtration. Volume I of the Proceedings has 49 papers from the following sessions: HEPA filter test methods; noble gas separation; air cleaning system design; containment venting; iodine adsorption; reprocessing offgas cleaning; critical review; filtration, filter testing, and aerosols. Volume II contains 44 papers from the sessions on: nuclear waste treatment; critical review; noble gas treatment; carbon-14 and tritium; air cleaning system response to stress; nuclear standards and safety; round table; open end; and air cleaning technology at Three Mile Island. Abstracts are provided for all of these papers

  14. Multicenter bonds, bond valence and bond charge apportion

    International Nuclear Information System (INIS)

    In the same way that the valence of an atom issues from the definition of bond index, we shoe here that the three-center bond index lends itself to the definition of a bond valence. Within the charge of a bond, we show that its self-charge (i.e., the amount of electron kept by the atoms involved in the bond) is parted in a such a way that the more electronegative atom tends to allot more electronic charge than the other atom. We give examples of these quantities and discuss the results for different kinds of chemical systems. We also show some results for four-center indices and report six-center indices for hexagonal rings. (author). 54 refs., 4 figs., 8 tabs

  15. Responses of RAW264.7 macrophages to water-dispersible gold and silver nanoparticles stabilized by metal-carbon σ-bonds.

    Science.gov (United States)

    Hashimoto, Masanori; Toshima, Hirokazu; Yonezawa, Tetsu; Kawai, Koji; Narushima, Takashi; Kaga, Masayuki; Endo, Kazuhiko

    2014-06-01

    Nanometals are currently receiving considerable attention for industrial and biomedical applications, but their potentially hazardous and toxic effects have not been extensively studied. This study evaluated the biological responses of novel water-dispersible gold (Au-NPs) and silver nanoparticles (Ag-NPs) stabilized by Au-C or Ag-C σ-bonds in cultured macrophages (RAW264.7), via analysis of the cell viability, the integrity of the plasma membrane, and the inflammatory and morphological properties. The cultured RAW264.7 was exposed to metal-NPs at various concentrations. The Ag-NPs showed cytotoxicity at high NP concentrations, but the cytotoxic effects of the Au-NPs were smaller than those of the Ag-NPs. For the microscopic analysis, both types of particles were internalized into cells, the morphological changes in the cells which manifested as an expansion of the vesicles' volume, were smaller for the Au-NPs compared with the Ag-NPs. For the Ag-NPs, the endocytosis abilities of the macrophages might have induced harmful effects, because of the expansion of the cell vesicles. Although an inflammatory response was observed for both the Au- and Ag-NPs, the harmful effects of the Au-NPs were smaller than those of the Ag-NPs, with minor morphological changes observed even after internalization of the NPs into the cells. PMID:23784947

  16. Enhancing Interfacial Bonding of a Biodegradable Calcium Polyphosphate/ Polyvinyl-urethane Carbonate Interpenetrating Phase Composite for Load Bearing Fracture Fixation Applications

    Science.gov (United States)

    Guo, Yi

    This thesis describe methods to improve the interfacial stability of an interpenetrating phase composite (IPC) (comprised of porous calcium polyphosphate and polyvinylurethanecarbonate), and to increase the hydrophobicity of the polymer phase. The current IPCs introduce covalent bonding between the two phases via silanizing agents to enhance the interfacial stability. Incorporation of the silanizing agents was also intended to reduce the IPC's sensitivity to interfacial hydration, thereby further enhancing the IPC's resistance to rapid degradation during aqueous solution aging. Lysine diisocyanate was used to increase the hydrophobic character in the polyvinylurethanecarbonate infiltrating resin. The polymer resins were infiltrated into porous CPP blocks with 25 volume % interconnected porosity and polymerized to produce the IPCs. After mechanical testing following a 28-day aging study it was found that the silanizing agents contributed to long-term stability of the mechanical properties under aqueous conditions. It was concluded that the mechanical properties and long-term stability were comparable to available nonmetallic and biodegradable composites, as well as being biocompatible to a preosteoblast model cell line.

  17. Clean Energy Manufacturing Analysis Center (CEMAC) 2015 Research Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Woodhouse, Michael; Mone, Christopher; Chung, Donald; Elgqvist, Emma; Das, Sujit; Mann, Margaret; Gossett, Scott

    2016-03-01

    CEMAC has conducted four major studies on the manufacturing of clean energy technologies. Three of these focused on the end product: solar photovoltaic modules, wind turbines, and automotive lithium-ion batteries. The fourth area focused on a key material for manufacturing clean energy technologies, carbon fiber. This booklet summarizes key findings of CEMAC work to date, describes CEMAC's research methodology, and describes work to come.

  18. Clean coal technologies

    International Nuclear Information System (INIS)

    The recent developments and implementations in clean coal technologies foe power generation and industry are reviewed in the present work. The requirements of the Clean Air Act in the United States, and the Directives of the European communities, on the limitations of emissions of pollutants from coal uses are firstly briefly reviewed, and later technological means that are available to coal producers and utilizers to comply with them. Coal cleaning, before combustion may be achieved by physical, chemical and biotechnological methods, these technologies are then examined as well as coal refining. The developments in clean coal combustion are extremely rapid, particularly in regard to poor coals, they are reviewed and in particular fluidized bed combustion, in its varieties, as well as coal gasification and combined cycle and the utilization of the gas in fuel cells. A further chapter is devoted to the control of emissions of gases from coal combustion, to reduce SO2 and NOx emitted in the atmosphere. The economic implications of the technologies are evaluated according to the most recent information available from published literature and from industry publications, and the results compared. The implications of meand to reduced the emission of CO2 to the atmosphere are also evaluated. (authors)

  19. Road-Cleaning Device

    Science.gov (United States)

    Roman, Harry T.

    2014-01-01

    Roadways are literally soaked with petrochemical byproducts, oils, gasoline, and other volatile substances that eventually run off into sewers and end up in rivers, waterways, and other undesirable places. Can the roads be cleaned of these wastes, with their proper disposal? Can vehicles, robots, or other devices be designed that could be driven…

  20. Mechanism of clean development

    International Nuclear Information System (INIS)

    The mechanism of clean development represents an opportunity to attract significant foreign investment for the realization of projects in a country like Colombia, characterized by its forest vocation and with enormous potential to reduce emissions in sectors of energy generation, industry, transport and agro-industry

  1. Burning clean and green

    International Nuclear Information System (INIS)

    A new style of oil burner has been developed for use on exploration platforms offshore. The design improves oil combustion through enhanced air induction, producing stable flames in the clean burn region which do not generate smoke and oil fallout. Successful tests have led to it now being ready for commercial exploitation. (UK)

  2. Acrylic vessel cleaning tests

    International Nuclear Information System (INIS)

    The acrylic vessel as constructed is dirty. The dirt includes blue tape, Al tape, grease pencil, gemak, the glue or residue form these tapes, finger prints and dust of an unknown composition but probably mostly acrylic dust. This dirt has to be removed and once removed, the vessel has to be kept clean or at least to be easily cleanable at some future stage when access becomes much more difficult. The authors report on the results of a series of tests designed: (a) to prepare typical dirty samples of acrylic; (b) to remove dirt stuck to the acrylic surface; and (c) to measure the optical quality and Th concentration after cleaning. Specifications of the vessel call for very low levels of Th which could come from tape residues, the grease pencil, or other sources of dirt. This report does not address the concerns of how to keep the vessel clean after an initial cleaning and during the removal of the scaffolding. Alconox is recommended as the cleaner of choice. This acrylic vessel will be used in the Sudbury Neutrino Observatory

  3. Clean Cities Tools

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-12-19

    The U.S. Department of Energy's Clean Cities offers a large collection of Web-based tools on the Alternative Fuels Data Center. These calculators, interactive maps, and data searches can assist fleets, fuels providers, and other transportation decision makers in their efforts to reduce petroleum use.

  4. Neutrino Detection With CLEAN

    CERN Document Server

    McKinsey, D N

    2005-01-01

    This article describes CLEAN, an approach to the detection of low-energy solar neutrinos and neutrinos released from supernovae. The CLEAN concept is based on the detection of elastic scattering events (neutrino-electron scattering and neutrino-nuclear scattering) in liquified noble gases such as liquid helium, liquid neon, and liquid xenon, all of which scintillate brightly in the ultraviolet. Key to the CLEAN technique is the use of a thin film of wavelength-shifting fluor to convert the ultraviolet scintillation light to the visible. This allows the same liquid to be used as both a passive shielding medium and an active self-shielding detector, allowing lower intrinsic radioactive backgrounds at low energies. Liquid neon is a particularly promising medium for CLEAN. Because liquid neon has a high scintillation yield, has no long-lived radioactive isotopes, and can be easily purified by use of cold traps, it is an ideal medium for the detection of rare nuclear events. In addition, neon is inexpensive, dense...

  5. WINDOW-CLEANING

    CERN Multimedia

    Environmental Section / ST-TFM

    2001-01-01

    The two-month window-cleaning session on the Meyrin, Prévessin and LEP sites will soon begin. The cleaning contractors will work from Monday to Saturday, every week from 4.00 a.m. to 8.00 p.m. The work will be organised so as to disturb users as little as possible. In any event, a work notice will be left in each office 24 hours beforehand. To prevent any damage to documents or items which could occur despite the precautions taken, please clear completely the window-sills and the area immediately around them. If, however, for valid reasons, the work cannot be done on the scheduled day, please inform the Environmental Section by telephoning: 73753 / 74233 / 72242 If you are going to be absent during this two-month period, we should be grateful if you would clear the above mentioned areas before your departure. REMINDER To allow more thorough cleaning of the entrance doors to buildings and also facilitate the weekly work of the cleaning contractors, we ask you to make use of the notice boards at the...

  6. CLEAN_LNAME: Stata module to clean lastname variables

    OpenAIRE

    Adrien Bouguen

    2015-01-01

    This program removes blanks, accents, full stops, hyphens and apostrophes within a string variable. It also returns the uppercased version of the variable. clean_lname (together with clean_fname) is particularly useful for name matching procedure.

  7. CLEAN_FNAME: Stata module to clean firstname variables

    OpenAIRE

    Adrien Bouguen

    2015-01-01

    This program removes blanks, accents, full stops, hyphens and apostrophes from a string variable. It returns the proper version of the variable. clean_fname (together with clean_lname) is particularly useful for name matching procedure.

  8. Fabrication and optoelectronic properties of novel films based on functionalized multiwalled carbon nanotubes and (phthalocyaninato)ruthenium(II) via coordination bonded layer-by-layer self-assembly.

    Science.gov (United States)

    Zhao, Wei; Tong, Bin; Shi, Jianbing; Pan, Yuexiu; Shen, Jinbo; Zhi, Junge; Chan, Wai Kin; Dong, Yuping

    2010-10-19

    4-(2-(4-pyridinyl)Ethynyl)benzenic diazonium salt (PBD) was used to modify multiwalled carbon nanotubes (MWCNTs) by the self-assembly technique. After the decomposition of the diazonium group in PBD under UV irradiation, the PBD monolayer film covalently anchored on multiwalled carbon nanotubes is very stable. The obtained pyridine-modified MWCNTs (Py(Ar)-MWCNTs) have good solubility in common organic solvents. Furthermore, the layer-by-layer (LBL) self-assembled fully conjugated films of Py(Ar)-MWCNTs and (phthalocyaninato)ruthenium(II) (RuPc) were fabricated on the PBD-modified substrates, and characterized using UV-vis absorption spectroscopy, scanning electron microscopy (SEM), and electrochemistry. The UV-vis analysis results indicate that the LBL RuPc/Py(Ar)-MWCNTs self-assembled multilayer films with axial ligands between the ruthenium atom and pyridine group were successfully fabricated, and the progressive assembly runs regularly with almost equal amounts of deposition in each cycle. A top view SEM image shows a random and homogeneous distribution of Py(Ar)-MWCNTs over the PBD-modified silicon substrate, which indicates well independence between all Py(Ar)-MWCNTs. Moreover, the opto-electronic conversion was also studied by assembling RuPc/Py(Ar)-MWCNTs multilayer films on PBD-modified ITO substrate. Under illumination, the LBL self-assembled films on ITO showed an effective photoinduced charge transfer because of their conjugated structure and the ITO current density changed with the number of bilayer. As the number of bilayers was increased, the photocurrent increases and reaches its maximum value (∼300 nA/cm(2)) at nine bilayers. These results allow us to design novel materials for applications in optoelectronic devices by using LBL self-assembly techniques. PMID:20853832

  9. Nature of chemical bond through positron annihilation

    International Nuclear Information System (INIS)

    Positron annihilation is an important alternative to Compton scattering for determination of electron momentum distribution. The possibility of studying the nature of chemical bond by positron annihilation technique is reviewed in this paper. General concepts connected with momentum space and chemical bond have been outlined. Estimation of positron wavefunction at carbon and hydrogen sites and the calculation of electron momentum distribution of C-H and C-C bonds are discussed. The annihilation with sigma electrons broadens the angular correlation curve while the annihilation with π electrons narrows the curve. The most significant part of this paper is the investigation of participation of d-orbital of sulphur in chemical bonding. Whether or not ligand perturbation is necessary for d-orbital contraction and consequent participation in bonding is controversial till now. A study of angular correlation of positron annihilation radiation on organic sulphides and sulphones is a direct evidence to conclude that ligand perturbation is necessary. (author)

  10. Clean Energy Solutions Center Services

    Energy Technology Data Exchange (ETDEWEB)

    2016-03-01

    The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  11. Handwashing: Clean Hands Save Lives

    Science.gov (United States)

    ... The CDC Cancel Submit Search The CDC Handwashing: Clean Hands Save Lives Note: Javascript is disabled or ... and what you can do if soap and clean, running water are not available. Whether you are ...

  12. Automated cleaning of electronic components

    International Nuclear Information System (INIS)

    Environmental and operator safety concerns are leading to the elimination of trichloroethylene and chlorofluorocarbon solvents in cleaning processes that remove rosin flux, organic and inorganic contamination, and particulates from electronic components. Present processes depend heavily on these solvents for manual spray cleaning of small components and subassemblies. Use of alternative solvent systems can lead to longer processing times and reduced quality. Automated spray cleaning can improve the quality of the cleaning process, thus enabling the productive use of environmentally conscious materials, while minimizing personnel exposure to hazardous materials. We describe the development of a prototype robotic system for cleaning electronic components in a spray cleaning workcell. An important feature of the prototype system is the capability to generate the robot paths and motions automatically from the CAD models of the part to be cleaned, and to embed cleaning process knowledge into the automatically programmed operations

  13. A microwave plasma cleaning apparatus

    Science.gov (United States)

    Tsai, C. C.; Nelson, W. D.; Schechter, D. E.; Thompson, L. M.; Glover, A. L.

    1995-01-01

    In a microwave electron cyclotron resonance plasma source, reactive plasmas of oxygen and its mixtures of argon have been used for evaluating plasma cleaning technologies. Small aluminum samples (0.95 x 1.9 cm) were coated with thin films (less than or equal to 20 micrometers in thickness) of Shell Vitrea oil and cleaned with reactive plasmas. The discharge parameters, such as gas pressure, magnetic field, substrate biasing, and microwave power, were varied to change cleaning conditions. A mass spectroscopy (or residual gas analyzer) was used to monitor the status of plasma cleaning. Mass loss of the samples after plasma cleaning was measured to estimate cleaning rates. Measured cleaning rates of low-pressure (0.5-m torr) argon/oxygen plasmas were as high as 2.7 micrometers/min. X-ray photoelectron spectroscopy was used to determine cleanliness of the sample surfaces. In this paper, significant results of the plasma cleaning are reported and discussed.

  14. Analysis of Single-Walled Carbon Nanotubes Using a Chemical Bond Element Model%一种用于分析单壁碳纳米管的纳米有限元方法

    Institute of Scientific and Technical Information of China (English)

    吕计男; 陈海波

    2008-01-01

    提出了一种纳米尺度的有限元方法,碳纳米管中的碳-碳化学键被模拟为键单元.按照平衡关系,根据有限元理论,作用于每个碳原了上的作用力可以写成键单元的刚度矩阵与每个碳原了位移的乘积.在分子力学的基本假设下,键单元刚度矩阵的每个元素可以写为分子力学中力场常数的函数,这样建立起了宏观力学方法(有限元)与纳米尺度力学方法(分了力学)之间的联系.应用该方法模拟了扶椅型与锯齿型单壁碳纳米管的力学行为从而验证了该方法的有效性.分析结果说叫单壁碳纳米管的弹性模量与管厚度的选取直接相关.此外,弹性模量刈所选取的分了力学中的力场常数非常敏感,管的弹性模量显示山对半径的尺度依赖性,但是管长度对弹性模造的影响小到可以被忽略.%A three dimensional nano-scale finite element model (FEM),called the chemical bond element model,is proposed for the simulation of mechanical properties of single-walled carbon nanotubes(SWCNTs) based upon molecular mechanics method.Chemical bonds between carbon atoms are modeled by chemical bond elements.The constants of a sub-stiffness matrix are determined by using a linkage between molecular mechanics and continuum mechanics.In order to evaluate the correctness and performance of the proposed model,simulation Was done to determine the influence of nanotube wall thickness.radius and length on the elastic modulus(Young's modulus and shear modulus)of SWCNTs.The simulation results show that the choice of wall thickness significantly affects the Young's modulus and shear modulus.The force field constants is also very important,because the elastic modulus is sensitive to force field constants and the elastic properties of SWCNT are related to the radii of the tubes.The contribution of length to elastic modulus is insignificant and can be ignored.In comparison with the Young's modulus and shear modulus reported in

  15. Credit ratings and cross-border bond market spillovers

    OpenAIRE

    Böninghausen, Benjamin; Zabel, Michael

    2015-01-01

    This paper studies spillovers across sovereign debt markets in the wake of sovereign rating changes. We compile an extensive dataset covering all announcements by the three major agencies (Standard & Poor’s, Moody’s, Fitch) and daily sovereign bond market movements of up to 73 developed and emerging countries between 1994 and 2011. To cleanly identify the existence of spillover effects, we perform an explicit counterfactual analysis which pits bond market reactions to small revisions in ratin...

  16. Self-cleaning geopolymer concrete - A review

    Science.gov (United States)

    Norsaffirah Zailan, Siti; Mahmed, Norsuria; Bakri Abdullah, Mohd Mustafa Al; Sandu, Andrei Victor

    2016-06-01

    Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

  17. Cryogenic evaluation of epoxy bond strength

    Science.gov (United States)

    Albritton, N.; Young, W.

    The purpose of the work presented here was to determine methods of optimizing the adhesion of a particular epoxy (CTD-101K, Composite Technology Development Inc.) to a particular nickel-based alloy substrate (Incoloy ® 908, Inco Alloys International) for cryogenic applications. Initial efforts were focused on surface preparation of the substrate material via various mechanical and chemical cleaning techniques. Test samples, fabricated to simulate the conduit-to-insulation interface, were put through a mock heat treat and vacuum/pressure impregnation process. Samples were compression/shear load tested to compare the bond strengths at room temperature and liquid nitrogen temperature. The resulting data indicate that acid etching creates a higher bond strength than the other tested techniques and that the bond formed is stronger at cryogenic temperatures than at room temperature. A description of the experiment along with the resulting data is presented here.

  18. Sustainable development with clean coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    This paper discusses the opportunities available with clean coal technologies. Applications include new power plants, retrofitting and repowering of existing power plants, steelmaking, cement making, paper manufacturing, cogeneration facilities, and district heating plants. An appendix describes the clean coal technologies. These include coal preparation (physical cleaning, low-rank upgrading, bituminous coal preparation); combustion technologies (fluidized-bed combustion and NOx control); post-combustion cleaning (particulate control, sulfur dioxide control, nitrogen oxide control); and conversion with the integrated gasification combined cycle.

  19. Falling behind - Canada's lost clean energy jobs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-05-15

    With the depletion of conventional resources and the increasing concerns about the environment, emphasis has been put on developing clean energy. Clean energy is expected to become one of the main industrial sectors within the next decade, thus creating numerous jobs. While significant investments have been made by several countries to shift to clean energy, Canada is investing in highly polluting resources such as the tar sands. It is shown that if Canada were to match U.S. efforts in terms of clean energy on a per person basis, they would need to invest 11 billion additional dollars and this would result in the creation of 66,000 clean energy jobs. This paper showed that Canada is falling behind in terms of clean energy and the authors recommend that the Canadian government match U.S. investments and design policies in support of clean energy and put a price on carbon so as to favor the development of the clean energy sector and its consequent job creation.

  20. Laser cleaning of Rakowicze sandstone

    NARCIS (Netherlands)

    Nijland, T.G.; Wijffels, T.J.

    2003-01-01

    Decisions about the cleaning of natural stone should always be made within the awareness of direct and indirect damage that may be the result of cleaning. During the last decade, laser cleaning of objects and monuments of natural stone has become increasingly popular. Whereas a considerable amount o

  1. Hydrogen bonded supramolecular structures

    CERN Document Server

    Li, Zhanting

    2015-01-01

    This book covers the advances in the studies of hydrogen-bonding-driven supramolecular systems  made over the past decade. It is divided into four parts, with the first introducing the basics of hydrogen bonding and important hydrogen bonding patterns in solution as well as in the solid state. The second part covers molecular recognition and supramolecular structures driven by hydrogen bonding. The third part introduces the formation of hollow and giant macrocycles directed by hydrogen bonding, while the last part summarizes hydrogen bonded supramolecular polymers. This book is designed to b

  2. Method of cleaning solvent

    International Nuclear Information System (INIS)

    In a solvent cleanup step for regenerating solvents released from the solvent extraction process in a reprocessing plan, fuel production plant, etc., extracted solvents are separated by means of freeze vacuum drying method into liquid concentrate comprising water, nitric acid, sublimaitng nuclides, n-dodecane, etc. and TPB residues, etcc. comprising tri-n-butylphosphate (TBP), dibutyl phthalate (DBP), butyl phosphate (MBP) and not-sublimating nuclear fuel materials and nuclear fission products. Then, the liquid concentrates are separated into an aqueous phase comprising water, nitric acid, etc. and an organic phase comprising n-dodecane, etc. The TBP residues, etc. are cleaned with a nitric acid solution to separate entraining nuclear fuel materials and nuclear fission products to re-utilize TBP. This can avoid the use of cleaning liquid and decrease the amount of liquid wastes generated to moderate burdens in the liquid wastes processing. Further, apparatus safety for corrosion, fire or explosion can be improved. (T.M.)

  3. Fuel assemblies chemical cleaning

    International Nuclear Information System (INIS)

    NPP Paks found a thermal-hydraulic anomaly in the reactor core during cycle 14 that was caused by corrosion product deposits on fuel assemblies (FAs) that increased the hydraulic resistance of the FAs. Consequently, the coolant flow through the FAs was insufficient resulting in a temperature asymmetry inside the reactor core. Based on this fact NPP Paks performed differential pressure measurements of all fuel assemblies in order to determine the hydraulic resistance and subsequently the limit values for the hydraulic acceptance of FAs to be used. Based on the hydraulic investigations a total number of 170 FAs was selected for cleaning. The necessity for cleaning the FAs was explained by the fact that the FAs were subjected to a short term usage in the reactor core only maximum of 1,5 years and had still a capacity for additional 2 fuel cycles. (authors)

  4. Improvement of interfacial bonding in carbon nanotube reinforced Fe–50Co composites by Ni–P coating: Effect on magnetic and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Mahesh Kumar, E-mail: metlymahesh@gmail.com [Wolfson Centre for Magnetics, Cardiff School of Engineering, Cardiff University (United Kingdom); Viola, Giuseppe; Reece, Mike J. [School of Engineering and Materials Science, Queen Mary University of London (United Kingdom); Nanoforce Technology Limited, London (United Kingdom); Hall, Jeremy P. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Cardiff University (United Kingdom); Evans, Sam L. [Institute of Mechanical and Manufacturing Engineering, Cardiff University (United Kingdom)

    2014-10-15

    Graphical abstract: - Highlights: • Drying of Ni–P coated CNTs in ethanol under atm. conditions promotes GO formation. • Ball milling helps to disperse CNTs uniformly in matrix than ultrasonication. • Increase in vol% of coated CNTs higher than 1.5% reduces mechanical properties. • Addition of coated CNTs improves both ductility and strength unlike bare CNTs. • Spark plasma sintering helped to preserve the structural quality of CNTs. - Abstract: Fe–50Co matrix composites containing 1.5 and 3 vol% of electroless Ni–P plated carbon nanotubes (CNTs) were densified using spark plasma sintering. The powder mixtures for the composites were prepared by two different routes: (a) ultrasonication only; and (b) ultrasonication followed by dry ball milling. Drying of the Ni–P plated CNTs under atmospheric conditions in the presence of ethanol promoted the nucleation and growth of graphene oxide on the coating. The ball milling route was found to be the most efficient method to disperse the coated nanotubes uniformly in the matrix. The addition of coated CNTs, which formed Taenite phase with the matrix alloy, made the composites to exhibit: (a) higher ductility, higher flexural strength, lower coercivity (H{sub c}) and lower saturation induction (B{sub sat}) compared to the monolithic material; and (b) higher ductility, higher flexural strength, higher H{sub c} and lower B{sub sat} in relation to the material with similar amount of bare CNTs.

  5. Improvement of interfacial bonding in carbon nanotube reinforced Fe–50Co composites by Ni–P coating: Effect on magnetic and mechanical properties

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Drying of Ni–P coated CNTs in ethanol under atm. conditions promotes GO formation. • Ball milling helps to disperse CNTs uniformly in matrix than ultrasonication. • Increase in vol% of coated CNTs higher than 1.5% reduces mechanical properties. • Addition of coated CNTs improves both ductility and strength unlike bare CNTs. • Spark plasma sintering helped to preserve the structural quality of CNTs. - Abstract: Fe–50Co matrix composites containing 1.5 and 3 vol% of electroless Ni–P plated carbon nanotubes (CNTs) were densified using spark plasma sintering. The powder mixtures for the composites were prepared by two different routes: (a) ultrasonication only; and (b) ultrasonication followed by dry ball milling. Drying of the Ni–P plated CNTs under atmospheric conditions in the presence of ethanol promoted the nucleation and growth of graphene oxide on the coating. The ball milling route was found to be the most efficient method to disperse the coated nanotubes uniformly in the matrix. The addition of coated CNTs, which formed Taenite phase with the matrix alloy, made the composites to exhibit: (a) higher ductility, higher flexural strength, lower coercivity (Hc) and lower saturation induction (Bsat) compared to the monolithic material; and (b) higher ductility, higher flexural strength, higher Hc and lower Bsat in relation to the material with similar amount of bare CNTs

  6. Influence of Different Post-Plasma Treatment Storage Conditions on the Shear Bond Strength of Veneering Porcelain to Zirconia

    Directory of Open Access Journals (Sweden)

    Mun-Hwan Lee

    2016-01-01

    Full Text Available This in vitro study investigated whether different storage conditions of plasma-treated zirconia specimens affect the shear bond strength of veneering porcelain. Zirconia plates were treated with a non-thermal atmospheric argon plasma (200 W, 600 s. Porcelain veneering (2.38 mm in diameter was performed immediately (P-I or after 24 h storage in water (P-W or air (P-A on the treated surfaces (n = 10. Untreated plates were used as the control. Each group was further divided into two subgroups according to the application of a ceramic liner. All veneered specimens underwent a shear bond strength (SBS test. In the X-ray photoelectron spectroscopy (XPS analysis, the oxygen/carbon ratios of the plasma-treated groups increased in comparison with those of the control group. When a liner was not used, the three plasma-treated groups showed significantly higher SBS values than the control group (p < 0.001, although group P-A exhibited a significantly lower value than the other two groups (p < 0.05. The liner application negatively affected bonding in groups P-I and P-W (p < 0.05. When the veneering step was delayed after plasma treatment of zirconia, storage of the specimens in water was effective in maintaining the cleaned surfaces for optimal bonding with the veneering porcelain.

  7. A Clean Market

    Institute of Scientific and Technical Information of China (English)

    MAGGIECHEN

    2004-01-01

    If you have US$1 million, do you invest in car production or cleaning car emissions? More cars than ever are hitting the roads and demand is rising.Cleaner cars are being called for, as the government strives to reduce car emission. So there is an obvious market both for cars and for new emission control technologies.Theoretically, you should make money by investing in either of them in China today.

  8. Clean Power on Tap

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China adopts the most advanced nuclear power technologies to meet long-term energy needs Nuclear power has taken center stage in China’s nationwide cam-paign to develop new and clean energy sources. In the latest effort, Chinese state-owned nuclear power giants invested over 40 billion yuan ($5.86 billion) as an initial funding injection to build a new plant under the

  9. Cleanly: trashducation urban system

    DEFF Research Database (Denmark)

    Reif, Inbal; Alt, Florian; Ramos, Juan David Hincapie;

    exacerbated by a poor personal trash management culture. In this paper we present Cleanly, an urban trashducation system aimed at creating awareness of garbage production and management, which may serve as an educational plat-form in the urban environment. We report on data collected from an online survey......, which not only motivates our research but also provides useful information on reasons and possible solutions for trash problems....

  10. Indonesia's Clean Air Program

    OpenAIRE

    Budy P. Resosudarmo

    2002-01-01

    Unprecedented industrial development in Indonesia during the last two decades, accompanied by a growing population, has increased the amount of environmental damage. One of the most important environmental problems is that the level of air pollution in several large cities has become alarming, particularly in the last few years. This high pollution level has stimulated the government to develop a national clean air program designed to control the quantity of pollutants in the air. However, th...

  11. Cleaning of contaminated XUV-optics at BESSY II

    CERN Document Server

    Eggenstein, F; Zeschke, T; Gudat, W

    2001-01-01

    Carbon contaminations as observed on XUV-optics can be removed by an in situ plasma discharge process. The method developed at BESSY is based on waterfree oxygen/argon mixture and avoids water contamination of the UHV-equipment. The radio frequency based plasma cleaning method has been used at several undulator beamlines at BESSY II with a gain in flux at the carbon K-edge. At the UE56-I-plane grating monochromator, a gain in flux up to a factor 20 is observed. No loss in flux has been observed across the whole energy ranges of the 'cleaned' beamlines.

  12. Saltstone Clean Cap Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C

    2005-04-22

    The current operation strategy for using Saltstone Vault 4 to receive 0.2 Ci/gallon salt solution waste involves pouring a clean grout layer over the radioactive grout prior to initiating pour into another cell. This will minimize the radiating surface area and reduce the dose rate at the vault and surrounding area. The Clean Cap will be used to shield about four feet of Saltstone poured into a Z-Area vault cell prior to moving to another cell. The minimum thickness of the Clean Cap layer will be determined by the cesium concentration and resulting dose levels and it is expected to be about one foot thick based on current calculations for 0.1 Ci Saltstone that is produced in the Saltstone process by stabilization of 0.2 Ci salt solution. This report documents experiments performed to identify a formulation for the Clean Cap. Thermal transient calculations, adiabatic temperature rise measurements, pour height, time between pour calculations and shielding calculations were beyond the scope and time limitations of this study. However, data required for shielding calculations (composition and specific gravity) are provided for shielding calculations. The approach used to design a Clean Cap formulation was to produce a slurry from the reference premix (10/45/45 weight percent cement/slag/fly ash) and domestic water that resembled as closely as possible the properties of the Saltstone slurry. In addition, options were investigated that may offer advantages such as less bleed water and less heat generation. The options with less bleed water required addition of dispersants. The options with lower heat contained more fly ash and less slag. A mix containing 10/45/45 weight percent cement/slag/fly ash with a water to premix ratio of 0.60 is recommended for the Clean Cap. Although this mix may generate more than 3 volume percent standing water (bleed water), it has rheological, mixing and flow properties that are similar to previously processed Saltstone. The recommended

  13. Saltstone Clean Cap Formulation

    International Nuclear Information System (INIS)

    The current operation strategy for using Saltstone Vault 4 to receive 0.2 Ci/gallon salt solution waste involves pouring a clean grout layer over the radioactive grout prior to initiating pour into another cell. This will minimize the radiating surface area and reduce the dose rate at the vault and surrounding area. The Clean Cap will be used to shield about four feet of Saltstone poured into a Z-Area vault cell prior to moving to another cell. The minimum thickness of the Clean Cap layer will be determined by the cesium concentration and resulting dose levels and it is expected to be about one foot thick based on current calculations for 0.1 Ci Saltstone that is produced in the Saltstone process by stabilization of 0.2 Ci salt solution. This report documents experiments performed to identify a formulation for the Clean Cap. Thermal transient calculations, adiabatic temperature rise measurements, pour height, time between pour calculations and shielding calculations were beyond the scope and time limitations of this study. However, data required for shielding calculations (composition and specific gravity) are provided for shielding calculations. The approach used to design a Clean Cap formulation was to produce a slurry from the reference premix (10/45/45 weight percent cement/slag/fly ash) and domestic water that resembled as closely as possible the properties of the Saltstone slurry. In addition, options were investigated that may offer advantages such as less bleed water and less heat generation. The options with less bleed water required addition of dispersants. The options with lower heat contained more fly ash and less slag. A mix containing 10/45/45 weight percent cement/slag/fly ash with a water to premix ratio of 0.60 is recommended for the Clean Cap. Although this mix may generate more than 3 volume percent standing water (bleed water), it has rheological, mixing and flow properties that are similar to previously processed Saltstone. The recommended

  14. Clean Energy Works Oregon Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Andria [City of Portland; Cyr, Shirley [Clean Energy Works

    2013-12-31

    In April 2010, the City of Portland received a $20 million award from the U.S. Department of Energy, as part of the Energy Efficiency and Conservation Block Grant program. This award was appropriated under the American Recovery and Reinvestment Act (ARRA), passed by President Obama in 2009. DOE’s program became known as the Better Buildings Neighborhood Program (BBNP). The BBNP grant objectives directed the City of Portland Bureau of Planning and Sustainability (BPS) as the primary grantee to expand the BPS-led pilot program, Clean Energy Works Portland, into Clean Energy Works Oregon (CEWO), with the mission to deliver thousands of home energy retrofits, create jobs, save energy and reduce carbon dioxide emissions.The Final Technical Report explores the successes and lessons learned from the first 3 years of program implementation.

  15. Bonding silicones with epoxies

    Energy Technology Data Exchange (ETDEWEB)

    Tira, J.S.

    1980-01-01

    It is shown that silicones, both room temperature vulcanizing (RTV) and millable rubber (press cured) can be successfully bonded to other materials using plasma treatment and epoxy adhesives. The plasma treatment using dry air atmosphere increases the surface energy of the silicone and thus provides a lower water contact angle. This phenomenon allows the epoxy adhesive to wet the silicone surface and ultimately bond. Bond strengths are sufficiently high to result in failures in the silicone materials rather than the adhesive bond.

  16. Australia's Bond Home Bias

    OpenAIRE

    Mishra, Anil V; Umaru B. Conteh

    2014-01-01

    This paper constructs the float adjusted measure of home bias and explores the determinants of bond home bias by employing the International Monetary Fund's high quality dataset (2001 to 2009) on cross-border bond investment. The paper finds that Australian investors' prefer investing in countries with higher economic development and more developed bond markets. Exchange rate volatility appears to be an impediment for cross-border bond investment. Investors prefer investing in countries with ...

  17. Glacial- interglacial temperature change based on 13C18O carbonate bond with in fish bone otoliths from Red Sea sediments

    Science.gov (United States)

    Ghosh, P.; Eiler, J.; Feeney, R.

    2006-12-01

    Determining the past record of temperature and salinity of ocean surface waters is essential for understanding past changes in climate, such as those which occur across glacial-interglacial transitions. As a useful proxy, the clumped isotope of CO2 in carbonate (13C18O16O or ?47) from inorganic precipitation experiment has been shown to reflect surface temperature with high degree of confidence (Ghosh et al., 2006). The last glacial cycle was characterized by climate fluctuations, but the extent of any associated changes in global sea level (or, equivalently, ice volume) remains elusive. High stands of sea level can be reconstructed from dated fossil and isotopic analyses of foraminifera and terapods, and these data are complemented by a compilation of global sea-level estimates based on deep-sea oxygen isotope ratios. Salinity derived from the records of oxygen isotopes ratios, however, contains uncertainties due to lack of information about the sea surface temperature change. Here we used combination of clumped isotopes technique and oxygen isotope measurement from fish otoliths (Myctophiformes; lanternfishes) extracted from two piston cores (Ku et al., 1969) (CH-154 and CH-153) to understand the temperature evolution and salinity variation of Red Sea water (300-800m) during the last 70 k.y. We analyzed well preserved unaltered otoliths from 7 different stratigraphic horizons from sediment core CH-154. Our preliminary observation suggests ~20 degree Celsius differences in sea water temperatures between glacial and interglacial time. We showed that the region has experienced fluctuation in climatic and tectonic processes during glacial interglacial time and the otoliths developed within the fishes captured the information about temperature change and salinity variation. Our results indicate a drop in temperature and restricted exchange of water with the open ocean during glaciations. The Red Sea environment was also highly saline even during the interglacial event

  18. Malaysia : Bond Market Development

    OpenAIRE

    International Monetary Fund; World Bank

    2013-01-01

    This paper pertains to the bond market development in Malaysia, and provides an overview of the market scenario in the country. Malaysia has been successful in developing the capital markets, particularly bond markets, in the recent past. Now, it faces the challenge of how to improve broader access and efficiency of the bond market. A high degree of investor concentration, dominated by gov...

  19. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  20. Clean development mechanism projects and portfolio risks

    International Nuclear Information System (INIS)

    Clean development mechanism (CDM) is expected to facilitate technology transfer from developed to developing countries as well as to economically reduce greenhouse gas emissions. In this article, we explore effective institutions to activate CDM projects. For this purpose, we have estimated internal rate of return (IRR) and other indicators on profitability for 42 CDM or JI projects, taking account of volatilities in the price of certified emission reductions (CER). As a result of Monte Carlo simulations, expected values and standard deviations in the IRR of the projects were quantitatively shown. Then we evaluated various risks in CDM, concluding that diversification of investment is an effective way to suppress these risks. Therefore securitization of CDM finance is proposed as a means of facilitating the diversification of investment. Namely, we present the concept of a CDM bond, which is a project bond with CER. We also investigated the role of governments to suppress risks in CDM. Referring to CERUPT, initiated by the Netherlands' government, the institution of 'insured CERUPT' is proposed to suppress downside risks in the IRR of the projects. We concluded that it is possible to make CDM projects viable by the 'insured CERUPT' and CDM bond

  1. Clean development mechanism projects and portfolio risks

    Energy Technology Data Exchange (ETDEWEB)

    Matsuhashi, Ryuji; Fujisawa, Sei [University of Tokyo (Japan). Graduate School of Frontier Science; Mitamura, Wataru; Momobayashi, Yutaka; Yoshida, Yoshikuni [University of Tokyo (Japan). Graduate School of Engineering

    2004-08-01

    Clean development mechanism (CDM) is expected to facilitate technology transfer from developed to developing countries as well as to economically reduce greenhouse gas emissions. In this article, we explore effective institutions to activate CDM projects. For this purpose, we have estimated internal rate of return (IRR) and other indicators on profitability for 42 CDM or JI projects, taking account of volatilities in the price of certified emission reductions (CER). As a result of Monte Carlo simulations, expected values and standard deviations in the IRR of the projects were quantitatively shown. Then we evaluated various risks in CDM, concluding that diversification of investment is an effective way to suppress these risks. Therefore securitization of CDM finance is proposed as a means of facilitating the diversification of investment. Namely, we present the concept of a CDM bond, which is a project bond with CER. We also investigated the role of governments to suppress risks in CDM. Referring to CERUPT, initiated by the Netherlands' government, the institution of ''insured CERUPT'' is proposed to suppress downside risks in the IRR of the projects. We concluded that it is possible to make CDM projects viable by the ''insured CERUPT'' and CDM bond. (author)

  2. Refining clean fuels for the future

    International Nuclear Information System (INIS)

    To which extent transportation fuels will reasonably be changed in the coming years? LPG and natural gas are expected to challenge conventional fuels, hydrogen and methanol are bounded to possible fuel cells development. Among others, security of supply, competitive economics and environmental protection issues will be the key to the changes in the coming years. But taking into account expected transportation development, liquid fuels from oil should prevail as the reference energy. Though most of technologies and catalysts needed for the future are still existing or under marketing plans, the industry has to cope with the growing share of middle distillates. Indeed future zero heavy fuel-oil refineries are technically feasible through many existing and recent technologies. However their potential profitability is weighed down deeply by the very high investments and operating costs which are tied up. Tomorrow's main gasoline challenges deal with sulfur in FCC gasoline, aromatics and olefins contents together with a possible ban of ethers, hampering future octane demand and its technical feasibility. In a similar way diesel oil issues for the future imply a very deep desulfurization with possible aromatics hydrogenation and rings opening in order to comply with cetane and poly-aromatics ratings. Natural gas upgrading via syngas chemistry is still expected to open the way to clean fuels for the future via improved and integrated FT's GTL technologies which could as a matter provide most of future increases in clean fuels demand without decreasing the related fatal carbon losses as CO2. As an overall view, clean fuels production for the future is technically feasible. Advanced hydro-refining and hydro-conversion technologies open the way to clean fuels and allow the best flexibility in the gasoline/middle distillates ratio. However cost reduction remains a key issue since the huge investments needed are faced with low and volatile refining margins. In addition, CO2

  3. Strength and leak testing of plasma activated bonded interfaces

    DEFF Research Database (Denmark)

    Visser, M.M.; Weichel, Steen; Reus, Roger De; Hanneborg, A.B.

    detection of changes in membrane deflections. The detection limit for leak was 8E-13 mbar l/s. For comparison, strength and leak tests were also performed with regular fusion bonded wafers annealed at 1100 degreesC. The PAB was found to withstand post-processing steps such as RCA cleaning, 24 h in de...

  4. Effect of carbon on the Ni catalyzed methane cracking reaction: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jingde; Croiset, Eric; Ricardez–Sandoval, Luis, E-mail: laricard@uwaterloo.ca

    2014-08-30

    Highlights: • Effect of carbon deposition on kinetic properties of methane dissociation is studied. • Existence of surface and subsurface C atoms destabilized CH{sub x} species adsorption. • CH{sub x} activation is hindered with the deposition of C on and in the Ni (1 1 1) surface. - Abstract: To understand the effects of carbon atoms on the Ni catalyzed methane cracking reactions, methane dissociation on clean, surface-carbon-covered, and subsurface-carbon-accumulated Ni(1 1 1) surfaces were investigated using density functional theory (DFT). The results show that the existence of surface and subsurface C atoms destabilized the adsorption of the surface hydrocarbon species when compared to the clean Ni(1 1 1) surface. The projected density state (PDOS) analysis shows that the deposition of C atoms on and into the Ni surface modified the electronic structure of the Ni surface, and thus reduced the catalytic activity of the bonded Ni atoms. Moreover, it was found that the presence carbon atoms increase the CH{sub x} (x = 4–1) species activation barriers especially on the surface carbon covered (1/4 ML) Ni(1 1 1) surface, where CH{sub x} (x = 4–1) species encounter highest energy barrier for dissociation due to the electronic deactivation induced by C-Ni bonding and the strong repulsive carbon -CH{sub x} interaction. The calculations also show that CH{sub x} dissociation barriers are not affected by its neighboring C atom at low surface carbon coverage (1/9 ML). This work can be used to estimate more realistic kinetic parameters for this system.

  5. Effect of carbon on the Ni catalyzed methane cracking reaction: A DFT study

    International Nuclear Information System (INIS)

    Highlights: • Effect of carbon deposition on kinetic properties of methane dissociation is studied. • Existence of surface and subsurface C atoms destabilized CHx species adsorption. • CHx activation is hindered with the deposition of C on and in the Ni (1 1 1) surface. - Abstract: To understand the effects of carbon atoms on the Ni catalyzed methane cracking reactions, methane dissociation on clean, surface-carbon-covered, and subsurface-carbon-accumulated Ni(1 1 1) surfaces were investigated using density functional theory (DFT). The results show that the existence of surface and subsurface C atoms destabilized the adsorption of the surface hydrocarbon species when compared to the clean Ni(1 1 1) surface. The projected density state (PDOS) analysis shows that the deposition of C atoms on and into the Ni surface modified the electronic structure of the Ni surface, and thus reduced the catalytic activity of the bonded Ni atoms. Moreover, it was found that the presence carbon atoms increase the CHx (x = 4–1) species activation barriers especially on the surface carbon covered (1/4 ML) Ni(1 1 1) surface, where CHx (x = 4–1) species encounter highest energy barrier for dissociation due to the electronic deactivation induced by C-Ni bonding and the strong repulsive carbon -CHx interaction. The calculations also show that CHx dissociation barriers are not affected by its neighboring C atom at low surface carbon coverage (1/9 ML). This work can be used to estimate more realistic kinetic parameters for this system

  6. Catalytic C-H bond stannylation: a new regioselective pathway to C-Sn bonds via C-H bond functionalization.

    Science.gov (United States)

    Doster, Meghan E; Hatnean, Jillian A; Jeftic, Tamara; Modi, Sunjay; Johnson, Samuel A

    2010-09-01

    The ubiquitous Stille coupling reaction utilizes Sn-C bonds and is of great utility to organic chemists. Unlike the B-C bonds used in the Miyaura-Suzuki coupling reaction, which are readily obtained via direct borylation of C-H bonds, routes to organotin compounds via direct C-H bond functionalization are lacking. Here we report that the nickel-catalyzed reaction of fluorinated arenes and pyridines with vinyl stannanes does not provide the expected vinyl compounds via C-F activation but rather provides new Sn-C bonds via C-H functionalization with the loss of ethylene. This mechanism provides a new unanticipated methodology for the direct conversion of C-H bonds to carbon-heteroatom bonds. PMID:20690675

  7. SURFACE MODIFICATION AND DISPERSION OF NANODIAMOND IN CLEAN OIL

    Institute of Scientific and Technical Information of China (English)

    Yongwei Zhu; Xiangyang Xu; Baichun Wang; Zhijing Feng

    2004-01-01

    The effect of different kinds of surfactants on the size distribution of nanodiamond particles in clean oil was studied. Results show that the dispersing stability of nanodiamond modified with surfactants YS-1 and SB-18 simultaneously is much better than those modified with either of them because of synergism of the surfactants. And the particle size distribution in the system can be improved remarkably after the adoption of hyperdispersants such as SA-E and SA-F. Anchoring groups of those hyperdispersants can be bonded with the particle surface by chemical and/or hydrogen bonding and their soluble chains are well compatible with the dispersion media. As a result, the particles are uniformly distributed in the system owing to the steric stabilization. A very stable clean-oil based nanodiamond suspension with an average particle size of around 53.2 nm was prepared.

  8. Combined wet and dry cleaning of SiGe(001)

    International Nuclear Information System (INIS)

    Combined wet and dry cleaning via hydrofluoric acid (HF) and atomic hydrogen on Si0.6Ge0.4(001) surface was studied at the atomic level using ultrahigh vacuum scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and x-ray photoelectron spectroscopy to understand the chemical transformations of the surface. Aqueous HF removes native oxide, but residual carbon and oxygen are still observed on Si0.6Ge0.4(001) due to hydrocarbon contamination from post HF exposure to ambient. The oxygen contamination can be eliminated by shielding the sample from ambient via covering the sample in the HF cleaning solution until the sample is introduced to the vacuum chamber or by transferring the sample in an inert environment; however, both processes still leave carbon contaminant. Dry in-situ atomic hydrogen cleaning above 330 °C removes the carbon contamination on the surface consistent with a thermally activated atomic hydrogen reaction with surface hydrocarbon. A postdeposition anneal at 550 °C induces formation of an atomically flat and ordered SiGe surface observed by STM. STS verifies that the wet and dry cleaned surface has an unpinned Fermi level with no states between the conduction and valence band edge comparable to sputter cleaned SiGe surfaces

  9. Combined wet and dry cleaning of SiGe(001)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Wook; Kaufman-Osborn, Tobin; Kim, Hyonwoong [Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States); Siddiqui, Shariq; Sahu, Bhagawan [TD Research, GLOBALFOUNDRIES USA, Inc., 257 Fuller Road, Albany, New York 12203 (United States); Yoshida, Naomi; Brandt, Adam [Applied Materials, Inc., Santa Clara, California 95054 (United States); Kummel, Andrew C., E-mail: akummel@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)

    2015-07-15

    Combined wet and dry cleaning via hydrofluoric acid (HF) and atomic hydrogen on Si{sub 0.6}Ge{sub 0.4}(001) surface was studied at the atomic level using ultrahigh vacuum scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and x-ray photoelectron spectroscopy to understand the chemical transformations of the surface. Aqueous HF removes native oxide, but residual carbon and oxygen are still observed on Si{sub 0.6}Ge{sub 0.4}(001) due to hydrocarbon contamination from post HF exposure to ambient. The oxygen contamination can be eliminated by shielding the sample from ambient via covering the sample in the HF cleaning solution until the sample is introduced to the vacuum chamber or by transferring the sample in an inert environment; however, both processes still leave carbon contaminant. Dry in-situ atomic hydrogen cleaning above 330 °C removes the carbon contamination on the surface consistent with a thermally activated atomic hydrogen reaction with surface hydrocarbon. A postdeposition anneal at 550 °C induces formation of an atomically flat and ordered SiGe surface observed by STM. STS verifies that the wet and dry cleaned surface has an unpinned Fermi level with no states between the conduction and valence band edge comparable to sputter cleaned SiGe surfaces.

  10. Clean electricity from photovoltaics

    CERN Document Server

    Green, Martin A

    2015-01-01

    The second edition of Clean Electricity from Photovoltaics , first published in 2001, provides an updated account of the underlying science, technology and market prospects for photovoltaics. All areas have advanced considerably in the decade since the first edition was published, which include: multi-crystalline silicon cell efficiencies having made impressive advances, thin-film CdTe cells having established a decisive market presence, and organic photovoltaics holding out the prospect of economical large-scale power production. Contents: The Past and Present (M D Archer); Limits to Photovol

  11. Clean fuels from biomass

    Science.gov (United States)

    Hsu, Y.-Y.

    1976-01-01

    The paper discusses the U.S. resources to provide fuels from agricultural products, the present status of conversion technology of clean fuels from biomass, and a system study directed to determine the energy budget, and environmental and socioeconomic impacts. Conversion processes are discussed relative to pyrolysis and anaerobic fermentation. Pyrolysis breaks the cellulose molecules to smaller molecules under high temperature in the absence of oxygen, wheras anaerobic fermentation is used to convert biomass to methane by means of bacteria. Cost optimization and energy utilization are also discussed.

  12. Clean electricity from photovoltaics

    CERN Document Server

    Archer, Mary D

    2001-01-01

    Photovoltaic cells provide clean, reversible electrical power from the sun. Made from semiconductors, they are durable, silent in operation and free of polluting emissions. In this book, experts from all sectors of the PV community - materials scientists, physicists, production engineers, economists and environmentalists - give their critical appraisals of where the technology is now and what its prospects are. Sample Chapter(s). Chapter 2.1: Introduction (306 KB). Chapter 2.2: Semiconductor device equations (121 KB). Chapter 2.3: The p-n junction model of Shockley (1,017 KB). Chapter 2.4: Rea

  13. Flue Gas Cleaning

    DEFF Research Database (Denmark)

    Fehrmann, Rasmus

    2014-01-01

    and sulfuric acid in the atmosphere causing precipitation of acid rain resulting in death of forests and destruction of buildings and monuments in addition to human health problems. The most common state-of-the-art methods applied today industrially for cleaning of flue gases will be addressed, including wet......-time. But the problems may also be attacked by new materials like supported ionic liquid phase (SILP) gas absorbers where the pollutants may be selectively absorbed, desorbed and finally converted to useful mineral acids of commercial grade – really a green waste-to-value approach that we persue instead...

  14. Clean coal technology

    International Nuclear Information System (INIS)

    Coal is the major source of energy in India at present as well as in foreseeable future. With gradual deterioration in coal quality as well as increased awareness on environmental aspects, clean coal technologies have to be adopted by major coal consuming sectors. The probable routes of restricting environmental degradation in power generation include beneficiation of power coal for maintaining consistency in coal supply and reducing pollutant emission, adoption of fluidized bed combustion on a larger scale, adoption of technologies for controlling SOx and NOx emission during and after combustion, adoption of larger capacity and improved and non-recovery type coke ovens

  15. Transforming Global Markets for Clean Energy Products

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This paper looks at three clean energy product categories: equipment energy efficiency; low-carbon transport, including high-efficiency vehicles and electric/plug-in hybrid electric vehicles (EV/PHEVs); and solar photovoltaic (PV) power. Each section identifies ways to enhance global co-operation among major economies through case studies and examples, and ends with specific suggestions for greater international collaboration on market transformation efforts. An annex with more detailed case studies on energy-efficient electric motors, televisions, external power supplies and compact fluorescent lights is included in the paper.

  16. Ductless personalized ventilation with local air cleaning

    OpenAIRE

    Dalewski, Mariusz; Vesely, Michal; Melikov, Arsen Krikor

    2012-01-01

    An experiment with 28 human subjects was performed to examine effects of using a local air cleaning device combined with ductless personalized ventilation (DPV) on perceived air quality. Experiments were performed in a test room with displacement ventilation. The DPV at one of two desks was equipped with an activated carbon filter installed at the air intake, while the DPV at the second desk was without such a filter. The air temperature in the occupied zone (1.1 m above the floor) was 29 °C....

  17. International Clean Energy Coalition

    Energy Technology Data Exchange (ETDEWEB)

    Erin Skootsky; Matt Gardner; Bevan Flansburgh

    2010-09-28

    In 2003, the National Association of Regulatory Utility Commissioners (NARUC) and National Energy Technology Laboratories (NETL) collaboratively established the International Clean Energy Coalition (ICEC). The coalition consisting of energy policy-makers, technologists, and financial institutions was designed to assist developing countries in forming and supporting local approaches to greenhouse gas mitigation within the energy sector. ICEC's work focused on capacity building and clean energy deployment in countries that rely heavily on fossil-based electric generation. Under ICEC, the coalition formed a steering committee consisting of NARUC members and held a series of meetings to develop and manage the workplan and define successful outcomes for the projects. ICEC identified India as a target country for their work and completed a country assessment that helped ICEC build a framework for discussion with Indian energy decisionmakers including two follow-on in-country workshops. As of the conclusion of the project in 2010, ICEC had also conducted outreach activities conducted during United Nations Framework Convention on Climate Change (UNFCCC) Ninth Conference of Parties (COP 9) and COP 10. The broad goal of this project was to develop a coalition of decision-makers, technologists, and financial institutions to assist developing countries in implementing affordable, effective and resource appropriate technology and policy strategies to mitigate greenhouse gas emissions. Project goals were met through international forums, a country assessment, and in-country workshops. This project focused on countries that rely heavily on fossil-based electric generation.

  18. Effects of fluid dynamics on cleaning efficacy of supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.R.; Willcox, W.A.; Silva, L.J.; Butner, R.S.

    1993-03-01

    Pacific Northwest Laboratory (PNL) and Boeing Aerospace Company are developing a process to clean metal parts using a supercritical solvent. This work is part of an effort to address issues inhibiting the rapid commercialization of Supercritical Fluid Parts Cleaning (SFPC). PNL assembled a SFPC test stand to observe the relationship between the fluid dynamics of the system and the mass transfer of a contaminant from the surface of a contaminated metal coupon into the bulk fluid. The bench-scale test stand consists of a ``Berty`` autoclave modified for these tests and supporting hardware to achieve supercritical fluids parts cleaning. Three separate sets of tests were conducted using supercritical carbon dioxide. For the first two tests, a single stainless steel coupon was cleaned with organic solvents to remove surface residue, doped with a single contaminant, and then cleaned in the SFPC test stand. Contaminants studied were Dow Corning 200 fluid (dimethylpolysiloxane) and Castle/Sybron X-448 High-temperature Oil (a polybutane/mineral oil mixture). A set of 5-minute cleaning runs was conducted for each dopant at various autoclave impeller speeds. Test results from the first two sets of experiments indicate that precision cleaning for difficult-to-remove contaminants can be dramatically improved by introducing and increasing turbulence within the system. Metal coupons that had been previously doped with aircraft oil were used in a third set of tests. The coupons were placed in the SFPC test stand and subjected to different temperatures, pressures, and run times at a constant impeller speed. The cleanliness of each part was measured by Optically Stimulated Electron Emission. The third set of tests show that levels of cleanliness attained with supercritical carbon dioxide compare favorably with solvent and aqueous cleaning levels.

  19. Effects of fluid dynamics on cleaning efficacy of supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.R.; Willcox, W.A.; Silva, L.J.; Butner, R.S.

    1993-03-01

    Pacific Northwest Laboratory (PNL) and Boeing Aerospace Company are developing a process to clean metal parts using a supercritical solvent. This work is part of an effort to address issues inhibiting the rapid commercialization of Supercritical Fluid Parts Cleaning (SFPC). PNL assembled a SFPC test stand to observe the relationship between the fluid dynamics of the system and the mass transfer of a contaminant from the surface of a contaminated metal coupon into the bulk fluid. The bench-scale test stand consists of a Berty'' autoclave modified for these tests and supporting hardware to achieve supercritical fluids parts cleaning. Three separate sets of tests were conducted using supercritical carbon dioxide. For the first two tests, a single stainless steel coupon was cleaned with organic solvents to remove surface residue, doped with a single contaminant, and then cleaned in the SFPC test stand. Contaminants studied were Dow Corning 200 fluid (dimethylpolysiloxane) and Castle/Sybron X-448 High-temperature Oil (a polybutane/mineral oil mixture). A set of 5-minute cleaning runs was conducted for each dopant at various autoclave impeller speeds. Test results from the first two sets of experiments indicate that precision cleaning for difficult-to-remove contaminants can be dramatically improved by introducing and increasing turbulence within the system. Metal coupons that had been previously doped with aircraft oil were used in a third set of tests. The coupons were placed in the SFPC test stand and subjected to different temperatures, pressures, and run times at a constant impeller speed. The cleanliness of each part was measured by Optically Stimulated Electron Emission. The third set of tests show that levels of cleanliness attained with supercritical carbon dioxide compare favorably with solvent and aqueous cleaning levels.

  20. The governance of clean energy in India: The clean development mechanism (CDM) and domestic energy politics

    International Nuclear Information System (INIS)

    This paper explores the ways in which clean energy is being governed in India. It does so in order to improve our understanding of the potential and limitations of carbon finance in supporting lower carbon energy transitions, and to strengthen our appreciation of the role of politics in enabling or frustrating such endeavors. In particular we emphasize the importance of politics and the nature of India's political economy in understanding the development of energy sources and technologies defined as ‘clean’ both by the United Nations Clean Development Mechanism (CDM) and leading international actors. By considering the broad range of institutions that exert formal and informal political influence over how the benefits and costs of the CDM are distributed, the paper highlights shortcomings in the narrow way in which CDM governance has been conceptualized to date. This approach goes beyond analysis of technocratic aspects of governance – often reduced to a set of institutional design issues – in order to appreciate the political nature of the trade-offs that characterize debates about India's energy future and the relations of power which will determine how, and on whose terms, they are resolved. - Highlights: • Clean energy governance in practice is shaped by political power and influence. • Governance of clean energy requires strong institutions from local to global levels. • Un-governed areas of energy policy are often as revealing of the exercise of power as areas where there explicit policy is in place. • Climate and carbon finance interventions need to better understand the landscape of political power which characterises India’s energy sector

  1. Online soot cleaning using infrasound

    Energy Technology Data Exchange (ETDEWEB)

    Torra i Fernandez, Eric; Ellebro, Martin [Infrafone AB, Stockholm (Sweden)

    2013-10-01

    The company Infrafone has been using infrasound as a soot cleaning method for more than 30 years. Infrasonic soot cleaning increases the efficiency, the availability and the lifetime of marine and industrial boilers. The properties and the description of infrasound and Infrafone's soot cleaning method are presented. Moreover, a brief comparison with audible sonic horns is carried out. The results and the savings of installing Infrafone's infrasonic cleaners are presented here with several case studies. (orig.)

  2. Weak bond screening system

    Science.gov (United States)

    Chuang, S. Y.; Chang, F. H.; Bell, J. R.

    Consideration is given to the development of a weak bond screening system which is based on the utilization of a high power ultrasonic (HPU) technique. The instrumentation of the prototype bond strength screening system is described, and the adhesively bonded specimens used in the system developmental effort are detailed. Test results obtained from these specimens are presented in terms of bond strength and level of high power ultrasound irradiation. The following observations were made: (1) for Al/Al specimens, 2.6 sec of HPU irradiation will screen weak bond conditions due to improper preparation of bonding surfaces; (2) for composite/composite specimens, 2.0 sec of HPU irradiation will disrupt weak bonds due to under-cured conditions; (3) for Al honeycomb core with composite skin structure, 3.5 sec of HPU irradiation will disrupt weak bonds due to bad adhesive or oils contamination of bonding surfaces; and (4) for Nomex honeycomb with Al skin structure, 1.3 sec of HPU irradiation will disrupt weak bonds due to bad adhesive.

  3. Facile scission of isonitrile carbon–nitrogen triple bond using a diborane(4) reagent

    OpenAIRE

    Asakawa, Hiroki; Lee, Ka-Ho; Lin, Zhenyang; Yamashita, Makoto

    2014-01-01

    Transition metal reagents and catalysts are generally effective to cleave all three bonds (one σ and two π) in a triple bond despite its high bonding energy. Recently, chemistry of single-bond cleavage by using main-group element compounds is rapidly being developed in the absence of transition metals. However, the cleavage of a triple bond using non-transition-metal compounds is less explored. Here we report that an unsymmetrical diborane(4) compound could react with carbon monoxide and tert...

  4. Feasibility of zeolitic imidazolate framework membranes for clean energy applications

    NARCIS (Netherlands)

    A. W. Thornton; D. Dubbeldam; M. S. Liu; B. P. Ladewig; A. J. Hill; M. R. Hill

    2012-01-01

    Gas separation technologies for carbon-free hydrogen and clean gaseous fuel production must efficiently perform the following separations: (1) H2/CO2 (and H2/N2) for pre-combustion coal gasification, (2) CO2/N2 for post-combustion of coal, (3) CO2/CH4 for natural gas sweetening and biofuel purificat

  5. Proceedings of the fifteenth DOE nuclear air cleaning conference

    Energy Technology Data Exchange (ETDEWEB)

    First, M.W. (ed.)

    1979-02-01

    Papers presented are grouped under the following topics: air cleaning; waste volume reduction and preparation for storage; tritium, carbon-14, ozone; containment of accidental releases; adsorbents and absorbents; and off-gas treatment. A separate abstract was prepared for each paper.

  6. C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis,Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions%C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis, Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; CHEN Ying; LIU Fang; LI Ping; HU Zhao-xia; WANG Hong-xing

    2013-01-01

    Abstract:The reactions of a variety of 4,6-dimethyl-1,3-bis (imino) benzenes 2a-g derived from 4,6-dimethylisophthalaldehyde and anilines or benzylamine with palladium (Ⅱ) acetate in anhydrous acetic acid under nitrogen were investigated.Experiment results demonstrate that cyclopalladations in such condition are applicable not only to the present system under study but also to the 5-substituted bis(imino)benzenes 6,7.The molecular structure of 3 b was further confirmed by X-Ray single-crystal diffraction.3b Crystallizes in orthorhombic,space groupP2 (1) 2 (1) 2 (1) with a =0.734 53 (8),b =1.683 8 (3),c =1.691 7(2) nm,α =β =γ =90°.Treatment of 2b with K2PtCl4 in anhydrous acetic acid affords the corresponding NCN-platinum pincer.Carbon-carbon cross coupling reactions catalyzed with 3b were investigated.These palladium complexes have been proved to be high effective catalysts for Suzuki coupling reaction.

  7. Full automatic clean-up robot for dioxin/PCB analysis

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, T.; Masuzaki, Y.; Takahashi, A.; Koizumi, A. [METOCEAN Environment Inc., Shizuoka (Japan). Environmental Risk Research Center, Inst. of General Science for Environment; Okuyama, H.; Kawada, Y.; Higashiguchi, T. [Moritex Corporation, Yokohama (Japan)

    2004-09-15

    Dioxin analysis requires several steps of clean-up procedures by combination of several column chromatography (e.g. silica gel column chromatography, carbon column chromatography) and sulfuric acid treatment. Full Automatic Clean-up Robot for Dioxin and PCB were developed.

  8. Rapid bonding of Pyrex glass microchips.

    Science.gov (United States)

    Akiyama, Yoshitake; Morishima, Keisuke; Kogi, Atsuna; Kikutani, Yoshikuni; Tokeshi, Manabu; Kitamori, Takehiko

    2007-03-01

    A newly developed vacuum hot press system has been specially designed for the thermal bonding of glass substrates in the fabrication process of Pyrex glass microchemical chips. This system includes a vacuum chamber equipped with a high-pressure piston cylinder and carbon plate heaters. A temperature of up to 900 degrees C and a force of as much as 9800 N could be applied to the substrates in a vacuum atmosphere. The Pyrex substrates bonded with this system under different temperatures, pressures, and heating times were evaluated by tensile strength tests, by measurements of thickness, and by observations of the cross-sectional shapes of the microchannels. The optimal bonding conditions of the Pyrex glass substrates were 570 degrees C for 10 min under 4.7 N/mm(2) of applied pressure. Whereas more than 16 h is required for thermal bonding with a conventional furnace, the new system could complete the whole bonding processes within just 79 min, including heating and cooling periods. Such improvements should considerably enhance the production rate of Pyrex glass microchemical chips. Whereas flat and dust-free surfaces are required for conventional thermal bonding, especially without long and repeated heating periods, our hot press system could press a fine dust into glass substrates so that even the areas around the dust were bonded. Using this capability, we were able to successfully integrate Pt/Ti thin film electrodes into a Pyrex glass microchip. PMID:17370301

  9. The governance of clean energy in India:The Clean Development Mechanism (CDM) and domestic energy politics

    OpenAIRE

    Phillips, Jon; Newell, Peter

    2013-01-01

    This paper explores the ways in which clean energy is being governed in India. It does so in order to improve our understanding of the potential and limitations of carbon finance in supporting lower carbon energy transitions, and to strengthen our appreciation of the role of politics in enabling or frustrating such endeavors. In particular we emphasize the importance of politics and the nature of India’s political economy in understanding the development of energy sources and technologies def...

  10. Carbon black recovery

    International Nuclear Information System (INIS)

    A process and apparatus for recovering carbon black from hot smoke which comprises passing the smoke through a cyclone separation zone following cooling, then through aggregate filter beds and regeneration of filter beds with clean off-gas which is recycled to the carbon black reaction zone as quench

  11. Cleaning of boreholes

    International Nuclear Information System (INIS)

    In terms of long-term safety it is a risk that the boreholes can eventually function as short-circuits between the repository and ground surface. Therefore sealing of investigation boreholes is an important issue for the long- term safety of high-level nuclear waste repositories. In order to seal a borehole properly, the conditions of the borehole have to meet certain predetermined requirements. One of the requirements is that no instruments or materials endangering the plugging operation or the long-term function of the sealing materials, are allowed to be left in the borehole. Sometimes drilling equipment will be left in the hole or it cannot be recovered from the hole with the given constraints of time, cost and resources in spite of attempts. Additionally various measurements may be carried out in the holes after the drilling has been completed and measuring devices may get stuck in holes. Consequently cleaning of the borehole is carried out as an essential activity before sealing can be implemented. There are two common reasons identified for the drill strings to get stuck in holes. First the drill string may get stuck due to acute drilling problems. The second case is where rods are left as casing in a hole either based on the structure of the upper part of the hole or in order to support the hole. To remove the drilling or measuring equipment lost in a borehole, special techniques and professional skill must be applied. Removing measuring equipment from a hole is often demanding and time consuming work. A vital part of the cleaning operation is planning the work in advance. In order to make the plan and to select the suitable methods it is important to know the condition of the stuck material. It is also important to know the exact depth where the equipment are stuck and to have an estimate of the reasons why they have got stuck. It is also very important to know the correct dimensions of the equipment or drill string before commencing the cleaning work

  12. Ultrasound cleaning of microfilters

    DEFF Research Database (Denmark)

    Hald, Jens; Bjørnø, Irina; Jensen, Leif Bjørnø

    1999-01-01

    The aim of the present work is to develop, design, and manufacture a high-power ultrasound transducer module to be used for preventing the blocking of plastic-based microfilters by organic materials, and possibly to prolong the lifetime of the filters in industry using the cavitation on the surface...... design suitable for cleaning of microfilters without damaging the filter structure. The filter surface was studied using an optical microscope before and after the experiment. When high-power ultrasound (max. 75 W/cm2) was applied to the surface of some microfilters, no visible damage was found, while...... others filters were damaged. The results of the laboratory experiments formed background for the final design of an ultrasound transducer module for use by foodstuff filtration plants. [This work was financed by the EU Project WAMBIO PL96-3257 (FAIR Programme).]...

  13. Flue gas cleaning chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gutberlet, H. [VEBA Kraftwerke Ruhr AG, Gelsenkirchen (Germany)

    1996-12-01

    The introduction of modern flue gas cleaning technology into fossil-fueled power stations has repeatedly confronted the power station chemists with new and interesting problems over the last 15 - 20 years. Both flue gas desulphurization by lime washing and catalytic removal of nitrogen oxides are based on simple basic chemical reactions. Owing to the use of readily available starting materials, the production of safe, useful end products and, last but not least, the possibility of implementing all this on an industrial scale by means of efficient process engineering, limestone desulphurization and catalytic removal of nitrogen oxides dominate the world market and, little by little, are becoming still more widespread. The origin and thus the quality of fuels and starting materials, the firing method, the mode of operation and engineering peculiarities in each plant interact in a complex manner. Simple cause/effect relationships are frequently incapable of explaining phenomena; thinking in complex interrelationships is needed. (EG)

  14. Clean Salt integrated flowsheet

    International Nuclear Information System (INIS)

    The Clean Salt Process (CSP) is a novel waste management scheme that removes sodium nitrate and aluminum nitrate nonahydrate as decontaminated (low specific activity) salts from Hanford's high-level waste (HLW). The full scale process will separate the bulk of the waste that exists as sodium salts from the small portion of the waste that is by definition radioactive and dangerous. This report presents initial conceptual CSP flowsheets and demonstrates the benefit of integrating the process into the Tank Waste Remediation Systems (TWRS) Reference Flowsheet. Total HLW and low-level (LLW) volumes are reported for two different CSP integration options and are compared to the TWRS Reference Flowsheet values. The results for a single glass option eliminating LLW disposal are also reported

  15. Bond Markets in Africa

    OpenAIRE

    Yibin Mu; Peter Phelps; Janet Gale Stotsky

    2013-01-01

    African bond markets have been steadily growing in recent years, but nonetheless remain undeveloped. African countries would benefit from greater access to financing and deeper financial markets. This paper compiles a unique set of data on corporate bond markets in Africa. It then applies an econometric model to analyze the key determinants of African government securities market and corporate bond market capitalization. Government securities market capitalization is directly related to bette...

  16. Build America Bonds

    OpenAIRE

    Andrew Ang; Vineer Bhansali; Yuhang Xing

    2010-01-01

    Build America Bonds (BABs) are a new form of municipal financing introduced in 2009. Investors in BAB municipal bonds receive interest payments that are taxable, but issuers receive a subsidy from the U.S. Treasury. The BAB program has succeeded in lowering the cost of funding for state and local governments with BAB issuers obtaining finance 54 basis points lower, on average, compared to issuing regular municipal bonds. For institutional investors, BAB issue yields are 116 basis points highe...

  17. Clean air Hamilton

    Energy Technology Data Exchange (ETDEWEB)

    McCarry, B.E. [McMaster Univ., Hamilton, ON (Canada)

    2002-07-01

    The industrial City of Hamilton is located on Lake Ontario, downwind from the Ohio Valley. The Hamilton Air Quality Initiative (HAQI) was divided in several phases, one of which is Clean Air Hamilton. This most recent phase was described in this presentation. Two major goals of this phase were: to ensure that the City of Hamilton has the best air quality of any major urban area in Ontario, and to reduce the emissions of greenhouse gases by 20 per cent compared to the levels in 1990. There were five main objectives to this initiative, namely: (1) the identification of priority air quality issues, (2) achieving an understanding of air quality issues, (3) the identification of sources, the evaluation of impacts and the recommendation of solutions, (4) the assessment of human health, and (5) the identification of further research. The reduction of air quality impacts is progressing through the support provided to the Drive Clean Program, the discouragement of vehicle idling, the support to car pooling initiatives, and the promotion of green vehicles. The implementation of pollution control technologies is taking place on the industrial side, as well as the development of plans to reduce steel industry emissions, the development of energy conservation measures and the promotion of green building practices. Efforts are being deployed over fleet greening partnerships, community tree planting program, an international air conference, an electronic information network linking the United States and the communities of Southern Ontario, a road dust study, a truck emissions research project, the assessment of human health impacts, and finally methods for the monitoring of local improvements. figs.

  18. Robust self-cleaning surfaces that function when exposed to either air or oil

    OpenAIRE

    Lu, Y

    2015-01-01

    Superhydrophobic self-cleaning surfaces are based on the surface micro/nanomorphologies; however, such surfaces are mechanically weak and stop functioning when exposed to oil. We have created an ethanolic suspension of perfluorosilane-coated titanium dioxide nanoparticles that forms a paint that can be sprayed, dipped, or extruded onto both hard and soft materials to create a self-cleaning surface that functions even upon emersion in oil. Commercial adhesives were used to bond the paint to va...

  19. The Bond Market's q

    OpenAIRE

    Thomas Philippon

    2006-01-01

    I propose an implementation of the q-theory of investment using bond prices instead of equity prices. Credit risk makes corporate bond prices sensitive to future asset values, and q can be inferred from bond prices. The bond market's q performs much better than the usual measure in standard investment equations. With aggregate data, the fit is three times better, cash flows are driven out and the implied adjustment costs are reduced by more than an order of magnitude. The new measure also imp...

  20. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...