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Sample records for high chemical inertness

  1. A chemically inert drug can stimulate T cells in vitro by their T cell receptor in non-sensitised individuals

    International Nuclear Information System (INIS)

    Engler, Olivier B.; Strasser, Ingrid; Naisbitt, Dean J.; Cerny, Andreas; Pichler, Werner J.

    2004-01-01

    Drugs can interact with T cell receptors (TCR) after binding to peptide-MHC structures. This binding may involve the formation of a stable, covalent bond between a chemically reactive drug and MHC or the peptide embedded within. Alternatively, if the drug is chemically inert, the binding may be non-covalent and readily reversible. Both types of drug presentation account for a substantial number of adverse side effects to drugs. Presently no tests are available to predict the ability of chemically inert drugs to stimulate an immune response. Here we present data on the successful induction of a primary T cell immune response in vitro against a chemically inert drug using blood from healthy individuals, previously not exposed to the drug. Blood lymphocytes were stimulated by the chemically inert drug sulfamethoxazole and the protein-reactive drug-metabolite sulfamethoxazole-nitroso in the presence of IL-2. 9/10 individuals reacted in response to sulfamethoxazole-nitroso, but only three reacted to the chemically inert compound sulfamethoxazole. Drug reactive T cells could be detected after 14-35 days of cell culture by drug-specific proliferation or cytotoxicity, which was MHC-restricted. These cells were CD4, CD8 positive or CD4/CD8 double positive and T cell clones generated secreted Th0 type cytokines. Drug interaction lead to down-regulation of specific TCR. These data confirm the ability of chemically inert drugs to stimulate certain T cells by their TCR and may provide the opportunity to screen new drugs for their ability to interact with TCRs

  2. Analysis of air-, moisture- and solvent-sensitive chemical compounds by mass spectrometry using an inert atmospheric pressure solids analysis probe.

    Science.gov (United States)

    Mosely, Jackie A; Stokes, Peter; Parker, David; Dyer, Philip W; Messinis, Antonis M

    2018-02-01

    A novel method has been developed that enables chemical compounds to be transferred from an inert atmosphere glove box and into the atmospheric pressure ion source of a mass spectrometer whilst retaining a controlled chemical environment. This innovative method is simple and cheap to implement on some commercially available mass spectrometers. We have termed this approach inert atmospheric pressure solids analysis probe ( iASAP) and demonstrate the benefit of this methodology for two air-/moisture-sensitive chemical compounds whose characterisation by mass spectrometry is now possible and easily achieved. The simplicity of the design means that moving between iASAP and standard ASAP is straightforward and quick, providing a highly flexible platform with rapid sample turnaround.

  3. Assessment of a chemical getter for scavenging tritium from an inert gas

    International Nuclear Information System (INIS)

    Maienschein, J.L.

    1976-01-01

    Results are presented of a study aimed at determining the feasibility of using chemical getter beds to scavenge tritium from inert gases. Two types of getter bed, fixed and fluidized, were considered, using cerium as the getter material. Mathematical-modeling results and capital-cost estimates indicate that not only is the gettering approach technically feasible, it could lead to considerable cost savings over catalytic oxidation, the tritium-removal method traditionally used

  4. Inert Reassessment Document for Acetone - CAS No. 67-64-1

    Science.gov (United States)

    Acetone is a highly volatile chemical that is used as an inert ingredient, a solvent/co-solvent, in a variety of pesticide products (including outdoor yard, garden and turf products, and agricultural crop products).

  5. A method for making an inert porous electrode for a chemical current source

    Energy Technology Data Exchange (ETDEWEB)

    Ksenzhek, O.S.; Litvinova, V.I.; Martynenko, T.L.; Raykhelson, L.B.; Shembel, Ye.M.; Sokolov, L.A.

    1983-01-01

    A method is proposed for making an inert, porous electrode for chemical current sources (KhIT) with a nonaqueous electrolyte on the basis of aprotonic solvents and an active cathode substance which is dissolved in the electrolyte. The method includes preparing an electrode mass from the starting material and subsequent formation of the electrode. To increase the energy capacity, after formation, the electrode is subjected to electrochemical anode polarization to potentials which correspond to the potential of electrochemical breakdown of the background electrolyte.

  6. Regenerable mixed copper-iron-inert support oxygen carriers for solid fuel chemical looping combustion process

    Energy Technology Data Exchange (ETDEWEB)

    Siriwardane, Ranjani V.; Tian, Hanjing

    2016-12-20

    The disclosure provides an oxygen carrier for a chemical looping cycle, such as the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The oxygen carrier is comprised of at least 24 weight % (wt %) CuO, at least 10 wt % Fe2O3, and an inert support, and is typically a calcine. The oxygen carrier exhibits a CuO crystalline structure and an absence of iron oxide crystalline structures under XRD crystallography, and provides an improved and sustained combustion reactivity in the temperature range of 600.degree. C.-1000.degree. C. particularly for solid fuels such as carbon and coal.

  7. A new understanding of inert gas narcosis

    International Nuclear Information System (INIS)

    Zhang Meng; Gao Yi; Fang Haiping

    2016-01-01

    Anesthetics are extremely important in modern surgery to greatly reduce the patient’s pain. The understanding of anesthesia at molecular level is the preliminary step for the application of anesthetics in clinic safely and effectively. Inert gases, with low chemical activity, have been found to cause anesthesia for centuries, but the mechanism is unclear yet. In this review, we first summarize the progress of theories about general anesthesia, especially for inert gas narcosis, and then propose a new hypothesis that the aggregated rather than the dispersed inert gas molecules are the key to trigger the narcosis to explain the steep dose-response relationship of anesthesia. (topical review)

  8. Bonding Characteristics and Chemical Inertness of Zr–Si–N Coatings with a High Si Content in Glass Molding

    Directory of Open Access Journals (Sweden)

    Li-Chun Chang

    2018-05-01

    Full Text Available High-Si-content transition metal nitride coatings, which exhibited an X-ray amorphous phase, were proposed as protective coatings on glass molding dies. In a previous study, the Zr–Si–N coatings with Si contents of 24–30 at.% exhibited the hardness of Si3N4, which was higher than those of the middle-Si-content (19 at.% coatings. In this study, the bonding characteristics of the constituent elements of Zr–Si–N coatings were evaluated through X-ray photoelectron spectroscopy. Results indicated that the Zr 3d5/2 levels were 179.14–180.22 and 180.75–181.61 eV for the Zr–N bonds in ZrN and Zr3N4 compounds, respectively. Moreover, the percentage of Zr–N bond in the Zr3N4 compound increased with increasing Si content in the Zr–Si–N coatings. The Zr–N bond of Zr3N4 dominated when the Si content was >24 at.%. Therefore, high Si content can stabilize the Zr–N compound in the M3N4 bonding structure. Furthermore, the thermal stability and chemical inertness of Zr–Si–N coatings were evaluated by conducting thermal cycle annealing at 270 °C and 600 °C in a 15-ppm O2–N2 atmosphere. The results indicated that a Zr22Si29N49/Ti/WC assembly was suitable as a protective coating against SiO2–B2O3–BaO-based glass for 450 thermal cycles.

  9. Inert gas transport in blood and tissues.

    Science.gov (United States)

    Baker, A Barry; Farmery, Andrew D

    2011-04-01

    This article establishes the basic mathematical models and the principles and assumptions used for inert gas transfer within body tissues-first, for a single compartment model and then for a multicompartment model. From these, and other more complex mathematical models, the transport of inert gases between lungs, blood, and other tissues is derived and compared to known experimental studies in both animals and humans. Some aspects of airway and lung transfer are particularly important to the uptake and elimination of inert gases, and these aspects of gas transport in tissues are briefly described. The most frequently used inert gases are those that are administered in anesthesia, and the specific issues relating to the uptake, transport, and elimination of these gases and vapors are dealt with in some detail showing how their transfer depends on various physical and chemical attributes, particularly their solubilities in blood and different tissues. Absorption characteristics of inert gases from within gas cavities or tissue bubbles are described, and the effects other inhaled gas mixtures have on the composition of these gas cavities are discussed. Very brief consideration is given to the effects of hyper- and hypobaric conditions on inert gas transport. © 2011 American Physiological Society. Compr Physiol 1:569-592, 2011.

  10. CHEMICAL-THERMAL PROCESSING OF TRACTOR PARTS IN VACUUM AT APPLICATION OF TECHNOLOGY OF HARDENING IN THE MEDIUM OF INERT GASES

    Directory of Open Access Journals (Sweden)

    статья Редакционная

    2011-01-01

    Full Text Available Advantages of technology of hardening by inert gases are considered. It is shown that use of unit ModulTherm7/1 at RUP «MTZ» allows to improve quality of chemical thermal processing of details and to provide decrease of expenses for manufacture.

  11. Defined media and inert supports : their potential as solid-state fermentation production systems

    NARCIS (Netherlands)

    Ooijkaas, L.P.; Weber, F.J.; Buitelaar, R.M.; Tramper, J.; Rinzema, A.

    2000-01-01

    Solid-state fermentation (SSF) using inert supports impregnated with chemically defined liquid media has several potential applications in both scientific studies and in the industrial production of high-value products, such as metabolites, biological control agents and enzymes. As a result of its

  12. Chemical identities of radioiodine released from U3O8 in oxygen and inert gas atmospheres

    International Nuclear Information System (INIS)

    Tachikawa, E.; Nakashima, M.

    1977-01-01

    Irradiated U 3 O 8 was heated from room temperature to 1100 0 C in a temperature-programmed oven (5 0 C/min) in a flow of carrier gas. The iodine released to an inert gas was deposited in the temperature range from 200 to 300 0 C with a peak at 250 0 C (speciesA). This species is neither in a form combined with other fission products nor in elemental form. It is possibly a chemical combination with uranium. It reacts with oxygen, yielding species B characterized by its deposition at a temperature close to room temperature. The activation energy of this oxidation reaction was determined to be 6.0 +-0.5 Kcal/mol. Comparing the deposition-profile with those obtained with carrier-free I 2 and HI indicated that species B was I 2 . As for the formation of organic iodides accompanying the release in an inert gas, it was concluded that these were produced in radical reactions. Thus, in a presence of oxygen, organic iodides were formed in competition with the reactions of organic radicals with oxygen. (author)

  13. Purification of inert gas circuits of nuclear power facilities from tritium and hydrogen

    International Nuclear Information System (INIS)

    Eichler, R.

    1985-08-01

    Removing hydrogen and tritium from the inert primary coolant of a high temperature reactor is very important in regard to the process heat disposition. In this work a gas purification for a high temperature module reactor was laid out constructionally and researched technically. This system removes the contamination of the primary circuit with the aid of chemical getter beds of Cer alloy particles. (orig./PW) [de

  14. Viking Helmet Corroles: Activating Inert Oxidometal Corroles.

    Science.gov (United States)

    Schweyen, Peter; Brandhorst, Kai; Hoffmann, Martin; Wolfram, Benedikt; Zaretzke, Marc-Kevin; Bröring, Martin

    2017-10-09

    Chemically inert oxidometal(V) corrols of molybdenum and rhenium undergo clean ligand-exchange reactions upon the action of SiCl 4 . The resulting dichlorido complexes show trigonal prismatic coordination of the metal ion with the chlorine atoms residing in a cis configuration, and were studied by optical and resonance spectroscopy as well as DFT calculations. In situ reactivity studies with carbon nucleophiles indicate high reactivity for chlorine replacement. Treatment with sodium cyclopentadienide paves the way to robust molybdenum corrolocene half-sandwich complexes. These organometallic compounds are the first corrole species that stabilize an air-stable and diamagnetic low spin d 2 -Mo IV center. Structural, spectroelectrochemical, and chemical investigations prove a reversible Mo IV /Mo V redox couple close to the Fc/Fc + potential for these systems. The high stability of the compounds in both redox states calls for future applications in catalysis and as redox switch. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Recoverying device for sodium vapor in inert gas

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Tamotsu; Nagashima, Ikuo

    1992-11-06

    A multi-pipe type heat exchanger for cooling an inert gas and a mist trap connected to the inert gas exit of the heat exchanger are disposed. A mist filter having bottomed pipes made of an inert gas-permeable sintered metal is disposed in the mist trap, and an inert gas discharge port is disposed at the upper side wall. With such a constitution, a high temperature inert gas containing sodium vapors can be cooled efficiently by the multi-pipe type heat exchanger capable of easy temperature control, thereby converting sodium vapors into mists, and the inert gas containing sodium mists can be flown into the mist trap. Sodium mists are collected by the mist filter and sodium mists flown down are discharged from the discharge port. With such procedures, a great amount of the inert gas containing sodium vapors can be processed continuously. (T.M.).

  16. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Katykhin, G.S.

    1978-01-01

    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  17. Dry boxes and inert atmosphere techniques

    International Nuclear Information System (INIS)

    Bartak, D.E.

    1987-01-01

    Practitioners need to conduct experiments with molten salts in an inert atmosphere owing to the chemical reactivity of these media. Most fused salt solvent systems show reactivity to water and/or oxygen, which results in significant chemical changes in the properties of these solvents. Although several studies on the nature of an oxygen/oxide electrode in this melt have been reported, the reactions have not been fully understood because of apparent water contamination in many cases. Nitrate melt systems are also hygroscopic; for example, the LiNO 3 -KNO 3 eutectic (177 0 C) absorbs water to at least 0.2% by weight. The result is that the electrochemistry of heavier, electropositive metal ions has been significantly altered. In addition, trace amounts of water have been shown to significantly affect the oxygen-oxide redox chemistry in NaNO 3 -KNO 3 melts (250 0 C). The haloaluminates, which include AlCl 3 -NaCl (175 0 C), as well as AlCl 3 -organic salt binaries are particularly sensitive to the presence of both oxygen and moisture. Oxygen is a strong oxidant in the fused hydroxide systems with formation of superoxide ion from either oxide or water. This chapter describes general, inert atmosphere techniques which can be used by the molten salt experimentalist. Because of the limitations of volatility, vacuum manipulations are not considered. Rather, the use of glove boxes, glove bags, and inert bench-top techniques are discussed. The areas covered are: glove box and bag equipment, operation and maintenance of glove boxes and glove bags, and common operations conducted inside glove boxes

  18. Development of an apparatus to study chemical reactions at high temperature - a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Sturzenegger, M; Schelling, Th; Steiner, E; Wuillemin, D [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    TREMPER is an apparatus that was devised to study kinetic and thermodynamic aspects of high-temperature reactions under concentrated solar irradiation. The design allows investigations on solid or liquid samples under inert or reactive atmospheres. The working temperature is adjustable; the upper limit that has yet been reached is about 1900 K. TREMPER will facilitate chemical reactivity studies on a temperature level that is difficult to access by other means. First experiments were conducted to study the decomposition of manganese oxide MnO{sub 2}. Chemical analysis of exposed samples confirmed that the parent MnO{sub 2} was decomposed to mixtures of Mn O and Mn{sub 3}O{sub 4}. The amount of Mn O ranged from 60 mol-% in air to 86 mol-% under inert atmosphere. (author) 1 fig., 1 tab., 2 refs.

  19. Catalytic Reactor for Inerting of Aircraft Fuel Tanks

    Science.gov (United States)

    1974-06-01

    Aluminum Panels After Triphase Corrosion Test 79 35 Inerting System Flows in Various Flight Modes 82 36 High Flow Reactor Parametric Data 84 37 System...AD/A-000 939 CATALYTIC REACTOR FOR INERTING OF AIRCRAFT FUEL TANKS George H. McDonald, et al AiResearch Manufacturing Company Prepared for: Air Force...190th Street 2b. GROUP Torrance, California .. REPORT TITLE CATALYTIC REACTOR FOR INERTING OF AIRCRAFT FUEL TANKS . OESCRIP TIVE NOTEs (Thpe of refpoft

  20. On the Benefits of Semi-Active Suspensions with Inerters

    Directory of Open Access Journals (Sweden)

    Xin-Jie Zhang

    2012-01-01

    Full Text Available Inerters have become a hot topic in recent years especially in vehicle, train, building suspension systems, etc. Eight different layouts of suspensions were analyzed with a quarter-car model in this paper. Dimensionless root mean square (RMS responses of the sprung mass vertical acceleration, the suspension travel, and the tire deflection are derived which were used to evaluate the performance of the quarter-car model. The behaviour of semi-active suspensions with inerters using Groundhook, Skyhook, and Hybrid control has been evaluated and compared to the performance of passive suspensions with inerters. Sensitivity analysis was applied to the development of a high performance semi-active suspension with an inerter. Numerical simulations indicate that a semi-active suspension with an inerter has much better performance than the passive suspension with an inerter, especially with the Hybrid control method, which has the best compromise between comfort and road holding quality.

  1. Inert materials for the GFR fuel. Characterizations, chemical interactions and irradiation damage

    International Nuclear Information System (INIS)

    Audubert, Fabienne; Carlot, Gaoelle; Lechelle, Jacques; David, Laurent; Gomes, Severine

    2005-01-01

    In the framework of an extensive R and D Program on GFR fuel, studies on inert materials have been performed at the French Atomic Energy Commission (CEA). The inert materials would be associated with the fuel with the aim of featuring an efficient barrier to radiotoxic species with regard to the cooling circuit of the reactor. Potential matrices identified for dispersion fuels or particles fuels are SiC, TiN, ZrN, ZrC, TiC. Physical microstructural and thermal properties have been determined in order to evaluate elaboration process effects. The evolution under irradiation of thermal properties (such as conductivity, diffusivity) of the materials has been studied using heavy ions to simulate fission product irradiation. After irradiation, scanning thermal microscopy is used to investigate the thermal degradation of the materials. Thermal conductivity variations were obtained on TiC irradiated with krypton ion at an energy of 86 MeV and a fluence of 5.10 15 ions.cm -2 . They are quantified at 19 W.m -1 .K -1 . On other materials such as SiC, ZrC, TiN, no thermal conductivity contrast was shown. Reactivity between the inert matrix (SiC or TiN) and the fuel (U, Pu)N have been evaluated on powders and on ceramic samples in contact by a thermal treatment under several atmospheres. It was shown that SiC reacts with (U, Pu)N in various atmospheres making secondary phases as PuSi 2 , USi 2 , U 20 Si 16 C 3 . TiN behaviour seems to be better: the only reactivity which may take place would be a variation of the nitrogen stoichiometry in TiN and (U, Pu)N at the interface. (author)

  2. Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

    Science.gov (United States)

    Ray, S.P.; Rapp, R.A.

    1986-04-22

    An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

  3. 46 CFR 153.923 - Inerting systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerting systems. 153.923 Section 153.923 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Requirements § 153.923 Inerting systems. The master shall ensure that the inert gas systems for any cargo that...

  4. Origins of inert Higgs doublets

    Directory of Open Access Journals (Sweden)

    Thomas W. Kephart

    2016-05-01

    Full Text Available We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.

  5. INERT GAS SHIELD FOR WELDING

    Science.gov (United States)

    Jones, S.O.; Daly, F.V.

    1958-10-14

    S>An inert gas shield is presented for arc-welding materials such as zirconium that tend to oxidize rapidly in air. The device comprises a rectangular metal box into which the welding electrode is introduced through a rubber diaphragm to provide flexibility. The front of the box is provided with a wlndow having a small hole through which flller metal is introduced. The box is supplied with an inert gas to exclude the atmosphere, and with cooling water to promote the solidification of the weld while in tbe inert atmosphere. A separate water-cooled copper backing bar is provided underneath the joint to be welded to contain the melt-through at the root of the joint, shielding the root of the joint with its own supply of inert gas and cooling the deposited weld metal. This device facilitates the welding of large workpieces of zirconium frequently encountered in reactor construction.

  6. Dynamic characteristics of stay cables with inerter dampers

    Science.gov (United States)

    Shi, Xiang; Zhu, Songye

    2018-06-01

    This study systematically investigates the dynamic characteristics of a stay cable with an inerter damper installed close to one end of a cable. The interest in applying inerter dampers to stay cables is partially inspired by the superior damping performance of negative stiffness dampers in the same application. A comprehensive parametric study on two major parameters, namely, inertance and damping coefficients, are conducted using analytical and numerical approaches. An inerter damper can be optimized for one vibration mode of a stay cable by generating identical wave numbers in two adjacent modes. An optimal design approach is proposed for inerter dampers installed on stay cables. The corresponding optimal inertance and damping coefficients are summarized for different damper locations and interested modes. Inerter dampers can offer better damping performance than conventional viscous dampers for the target mode of a stay cable that requires optimization. However, additional damping ratios in other vibration modes through inerter damper are relatively limited.

  7. Experimental study of an aircraft fuel tank inerting system

    Directory of Open Access Journals (Sweden)

    Cai Yan

    2015-04-01

    Full Text Available In this work, a simulated aircraft fuel tank inerting system has been successfully established based on a model tank. Experiments were conducted to investigate the influences of different operating parameters on the inerting effectiveness of the system, including flow rate of the inert gas (nitrogen-enriched air, inert gas concentration, fuel load of the tank and different inerting approaches. The experimental results show that under the same operating conditions, the time span of a complete inerting process decreased as the flow rate of inert gas was increased; the time span using the inert gas with 5% oxygen concentration was much longer than that using pure nitrogen; when the fuel tank was inerted using the ullage washing approach, the time span increased as the fuel load was decreased; the ullage washing approach showed the best inerting performance when the time span of a complete inerting process was the evaluation criterion, but when the decrease of dissolved oxygen concentration in the fuel was also considered to characterize the inerting effectiveness, the approach of ullage washing and fuel scrubbing at the same time was the most effective.

  8. An Inert Continuous Microreactor for the Isolation and Analysis of a Single Microbial Cell

    Directory of Open Access Journals (Sweden)

    Katrin Rosenthal

    2015-11-01

    Full Text Available Studying biological phenomena of individual cells is enabled by matching the scales of microbes and cultivation devices. We present a versatile, chemically inert microfluidic lab-on-a-chip (LOC device for biological and chemical analyses of isolated microorganisms. It is based on the Envirostat concept and guarantees constant environmental conditions. A new manufacturing process for direct fusion bonding chips with functional microelectrodes for selective and gentle cell manipulation via negative dielectrophoresis (nDEP was generated. The resulting LOC system offered a defined surface chemistry and exceptional operational stability, maintaining its structural integrity even after harsh chemical treatment. The microelectrode structures remained fully functional after thermal bonding and were proven to be efficient for single-cell trapping via nDEP. The microfluidic network consisted solely of glass, which led to enhanced chip reusability and minimized interaction of the material with chemical and biological compounds. We validated the LOC for single-cell studies with the amino acid secreting bacterium Corynebacterium glutamicum. Intracellular l-lysine production dynamics of individual bacteria were monitored based on a genetically encoded fluorescent nanosensor. The results demonstrate the applicability of the presented LOC for pioneering chemical and biological studies, where robustness and chemically inert surfaces are crucial parameters for approaching fundamental biological questions at a single-cell level.

  9. Inert Carbon Nanoparticles for the Assessment of Preferential Flow in Saturated Dual-Permeability Porous Media

    KAUST Repository

    Yao, Chuanjin

    2017-06-07

    Knowledge of preferential flow in heterogeneous environments is essential for enhanced hydrocarbon recovery, geothermal energy extraction, and successful sequestration of chemical waste and carbon dioxide. Dual tracer tests using nanoparticles with a chemical tracer could indicate the preferential flow. A dual-permeability model with a high permeable core channel surrounded by a low permeable annulus was constructed and used to determine the viability of an inert carbon nanoparticle tracer for this application. A series of column experiments were conducted to demonstrate how this nanoparticle tracer can be used to implement the dual tracer tests in heterogeneous environments. The results indicate that, with the injection rate selected and controlled appropriately, nanoparticles together with a chemical tracer can assess the preferential flow in heterogeneous environments. The results also implement the dual tracer tests in heterogeneous environments by simultaneously injecting chemical and nanoparticle tracers.

  10. Rare earth oxide reinforced Al{sub 2}O{sub 3}-TiO{sub 2} ceramics for inert coating of metallic parts for petroleum extraction

    Energy Technology Data Exchange (ETDEWEB)

    Yadava, Yoggendra Prasad; Rego, Sheila Alves Bezerra da Costa; Ferreira, Ricardo Artur Sanguinetti [Universidade Federal de Pernambuco (UFPE), Recife (Brazil)

    2012-07-01

    Recent findings of largest known pre-salt petroleum reservoir in Brazil have created an intense demand for new materials capable of withstanding direct contact with the crude petroleum as it is a highly corrosive and chemically reactive fluid. Petroleum drilling equipment, storage tanks and transportation systems suffer from constant physical stress caused by chemical attack of crude petroleum on its structure. Ceramics are materials with high chemical stability in hostile environment and therefore can be used as an inert coating material to resolve such problems. To date, ceramics based on alumina are most widely used in practice where there is demand for high mechanical strength and high fracture toughness. However intrinsic fragility of ceramics is still a fatal factor for their use in mechanical structures. To improve these characteristics, usually ceramics are reinforced with one or more ceramic additives. Mechanical properties of alumina based ceramics improve considerably with the addition of TiO{sub 2}, TiN, ZrO{sub 2} etc. ceramic additives. Nucleation and propagation of cracks is a major problem for ceramic coating applications. Initial studies show that addition of small percentages of rare earth oxides can increase the toughness of the alumina based ceramics. In the present work, we have produced rare-earth oxide (CeO{sub 2}) reinforced Al{sub 2}O{sub 3}-TiO{sub 2} ceramics in proportions of 5-20 wt% TiO{sub 2} and 2%wt% CeO{sub 2} through thermomechanical processing and sintering techniques and studied there microstructural characteristics and mechanical properties. To evaluate the potential of these ceramics as inert coatings for crude petroleum extraction, storage and transportation systems, we have studied the physic-chemical and mechanical stability of these ceramics in crude petroleum environment. Our studies presented satisfactory results in terms of physic-chemical and mechanical stability of these materials for the use of 2wt% of CeO{sub 2

  11. In situ laser-induced breakdown spectroscopy measurements of chemical compositions in stainless steels during tungsten inert gas welding

    Science.gov (United States)

    Taparli, Ugur Alp; Jacobsen, Lars; Griesche, Axel; Michalik, Katarzyna; Mory, David; Kannengiesser, Thomas

    2018-01-01

    A laser-induced breakdown spectroscopy (LIBS) system was combined with a bead-on-plate Tungsten Inert Gas (TIG) welding process for the in situ measurement of chemical compositions in austenitic stainless steels during welding. Monitoring the weld pool's chemical composition allows governing the weld pool solidification behavior, and thus enables the reduction of susceptibility to weld defects. Conventional inspection methods for weld seams (e.g. ultrasonic inspection) cannot be performed during the welding process. The analysis system also allows in situ study of the correlation between the occurrence of weld defects and changes in the chemical composition in the weld pool or in the two-phase region where solid and liquid phase coexist. First experiments showed that both the shielding Ar gas and the welding arc plasma have a significant effect on the selected Cr II, Ni II and Mn II characteristic emissions, namely an artificial increase of intensity values via unspecific emission in the spectra. In situ investigations showed that this artificial intensity increase reached a maximum in presence of weld plume. Moreover, an explicit decay has been observed with the termination of the welding plume due to infrared radiation during sample cooling. Furthermore, LIBS can be used after welding to map element distribution. For austenitic stainless steels, Mn accumulations on both sides of the weld could be detected between the heat affected zone (HAZ) and the base material.

  12. INERT Atmosphere confinement operability test procedure

    International Nuclear Information System (INIS)

    RISENMAY, H.R.

    1999-01-01

    This Operability Test Procedure (OTP) provides instructions for testing operability of the Inert Atmosphere Confinement (IAC). The Inert Atmosphere Confinement was designed and built for opening cans of metal items that might have hydrided surfaces. Unreviewed Safety Question (USQ) PFP-97-005 addresses the discovery of suspected plutonium hydride forming on plutonium metal currently stored in the Plutonium Finishing Plant vaults. Plutonium hydride reacts quickly with air, liberating energy. The Inert Atmosphere Confinement was designed to prevent this sudden liberation of energy by opening the material in an inert argon atmosphere instead of the normal glovebox atmosphere. The IAC is located in glovebox HC-21A, room 230B of the 234-5Z Building at the Plutonium Finishing Plant (PFP) in the 200-West Area of the Hanford Site

  13. Innovative inert matrix-thoria fuels for in-reactor plutonium disposition

    International Nuclear Information System (INIS)

    Vettraino, F.; Padovani, E.; Luzzi, L.; Lombardi, C.; Thoresen, H.; Oberlander, B.; Iversen, G.; Espeland, M.

    1999-01-01

    The present leading option for plutonium disposition, either civilian or weapons Pu, is to burn it in LWRs after having converted it to MOX fuel. However, among the possible types of fuel which can be envisaged to burn plutonium in LWRs, innovative U-free fuels such as inert matrix and thoria fuel are novel concept in view of a more effective and ultimate solution from both security and safety standpoint. Inert matrix fuel is an non-fertile oxide fuel consisting of PuO 2 , either weapon-grade or reactor-grade, diluted in inert oxides such as for ex. stabilized ZrO 2 or MgAl 2 O 4 , its primary advantage consisting in no-production of new plutonium during irradiation, because it does not contain uranium (U-free fuel) whose U-238 isotope is the departure nuclide for breeding Pu-239. Some thoria addition in the matrix (thoria-doped fuel) may be required for coping with reactivity feedback needs. The full thoria-plutonia fuel though still a U-free variant cannot be defined non-fertile any more because the U-233 generation. The advantage of such a fuel option consisting basically on a remarkable already existing technological background and a potential acceleration in getting rid of the Pu stocks. All U-free fuels are envisaged to be operated under a once-through cycle scheme being the spent fuel outlooked to be sent directly to the final disposal in deep geological formations without requiring any further reprocessing treatment, thanks to the quality-poor residual Pu and a very high chemical stability under the current fuel reprocessing techniques. Besides, inert matrix-thoria fuel technology is suitable for in-reactor MAs transmutation. An additional interest in Th containing fuel refers to applicability in ADS, the innovative accelerated driven subcritical systems, specifically aimed at plutonium, minor actnides and long lived fission products transmutation in a Th-fuel cycle scheme which enables to avoid generations of new TRUs. A first common irradiation experiment

  14. Compound forming extractants, solvating solvents and inert solvents IUPAC chemical data series

    CERN Document Server

    Marcus, Y; Kertes, A S

    2013-01-01

    Equilibrium Constants of Liquid-Liquid Distribution Reactions, Part III: Compound Forming Extractants, Solvating Solvents, and Inert Solvents focuses on the compilation of equilibrium constants of various compounds, such as acids, ions, salts, and aqueous solutions. The manuscript presents tables that show the distribution reactions of carboxylic and sulfonic acid extractants and their dimerization and other reactions in the organic phase and extraction reactions of metal ions from aqueous solutions. The book also states that the inorganic anions in these solutions are irrelevant, since they d

  15. Comfort-oriented vehicle suspension design with skyhook inerter configuration

    Science.gov (United States)

    Hu, Yinlong; Chen, Michael Z. Q.; Sun, Yonghui

    2017-09-01

    This paper is concerned with the comfort-oriented vehicle suspension design problem by using a skyhook inerter configuration. The rationale of the skyhook inerter is to use a grounded inerter to virtually increase the sprung mass of a vehicle, as it is analytically demonstrated that increasing the sprung mass can always improve the ride comfort performance. Semi-active means to realize the skyhook inerter configuration are investigated by using semi-active inerters. Three control laws, that is the on-off control, the anti-chatter on-off control, and the continuous control, are proposed for the semi-active inerter to approximate the skyhook inerter. Numerical simulations are performed to demonstrate the effectiveness and performances of these control laws. It is shown that the semi-active realizations of the skyhook inerter by using the proposed control laws can achieve over 10% improvement compared with the traditional strut, and similar performances are obtained for these control laws, with slight differences with respect to different static stiffnesses of the suspension system.

  16. Does the Addition of Inert Gases at Constant Volume and Temperature Affect Chemical Equilibrium?

    Science.gov (United States)

    Paiva, Joao C. M.; Goncalves, Jorge; Fonseca, Susana

    2008-01-01

    In this article we examine three approaches, leading to different conclusions, for answering the question "Does the addition of inert gases at constant volume and temperature modify the state of equilibrium?" In the first approach, the answer is yes as a result of a common students' alternative conception; the second approach, valid only for ideal…

  17. Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Addai, Emmanuel Kwasi, E-mail: emmanueladdai41@yahoo.com; Gabel, Dieter; Krause, Ulrich

    2016-04-15

    Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

  18. Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

    International Nuclear Information System (INIS)

    Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

    2016-01-01

    Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

  19. 46 CFR 154.910 - Inert gas piping: Location.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas piping: Location. 154.910 Section 154.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.910 Inert gas piping: Location. Inert gas piping must...

  20. Modeling, Testing, and Characteristic Analysis of a Planetary Flywheel Inerter

    Directory of Open Access Journals (Sweden)

    Zheng Ge

    2018-01-01

    Full Text Available We propose the planetary flywheel inerter, which is a new type of ball screw inerter. A planetary flywheel consists of several planetary gears mounted on a flywheel bracket. When the flywheel bracket is driven by a screw and rotating, each planetary gear meshing with an outer ring gear generates a compound motion composed of revolution and rotation. Theoretical analysis shows that the output force of the planetary flywheel inerter is proportional to the relative acceleration of one terminal of the inerter to the other. Optimizing the gear ratio of the planetary gears to the ring gear allows the planetary flywheel to be lighter than its traditional counterpart, without any loss on the inertance. According to the structure of the planetary flywheel inerter, nonlinear factors of the inerter are analyzed, and a nonlinear dynamical model of the inerter is established. Then the parameters in the model are identified and the accuracy of the model is validated by experiment. Theoretical analysis and experimental data show that the dynamical characteristics of a planetary flywheel inerter and those of a traditional flywheel inerter are basically the same. It is concluded that a planetary flywheel can completely replace a traditional flywheel, making the inerter lighter.

  1. Fog inerting criteria for hydrogen/air mixtures

    International Nuclear Information System (INIS)

    Tsai, S.S.; Liparulo, N.J.

    1982-01-01

    A distributed ignition system has been proposed to ignite hydrogen at low concentration in the ice condenser containment during severe accidents. The post-accident containment atmosphere could be misty due to fog generation from the break flow and condensation in the ice bed. Thus it is important to establish a fog inerting criterion for effective performance of the ignition system. This paper presents such a criterion that specifies the necessary fogging conditions, i.e., fog concentration and drop size, for inerting a hydrogen/air mixture. The criterion shows that the minimum fog inerting concentration varies with the square of the volume mean fog drop size. The present fog inerting criterion is shown to be in general agreement with the Factory Mutual test data

  2. Nucleosynthesis confronts an unstable inert 17 keV state

    International Nuclear Information System (INIS)

    Enqvist, K.; Kainulainen, K.; Thomson, M.

    1991-01-01

    We study the cosmological consequences of an inert 17 keV state mixing with the electron neutrino. We find that the nucleosynthesis upper bound on the primordial helium abundance prohibits the existence of such a state, unless its lifetime falls into the range 6x10 -4 s vac -2 s. In this range the decay occurs after the chemical decoupling of the electron neutrinos and before the beginning of the nucleosynthesis, with the result that the predicted helium abundance can be lower than what it would be in the standard scenario. (orig.)

  3. Pyrochemical separation of radioactive components from inert materials in ICPP high-level calcined waste

    International Nuclear Information System (INIS)

    Del Debbio, J.A.; Nelson, L.O.; Todd, T.A.

    1995-05-01

    Since 1963, calcination of aqueous wastes from reprocessing of DOE-owned spent nuclear fuels has resulted in the accumulation of approximately 3800 m 3 of high-level waste (HLW) at the Idaho Chemical Processing Plant (ICPP). The waste is in the form of a granular solid called calcine and is stored on site in stainless steel bins which are encased in concrete. Due to the leachability of 137 Cs and 90 Sr and possibly other radioactive components, the calcine is not suitable for final disposal. Hence, a process to immobilize calcine in glass is being developed. Since radioactive components represent less than 1 wt % of the calcine, separation of actinides and fission products from inert components is being considered to reduce the volume of HLW requiring final disposal. Current estimates indicate that compared to direct vitrification, a volume reduction factor of 10 could result in significant cost savings. Aqueous processes, which involve calcine dissolution in nitric acid followed by separation of actinide and fission products by solvent extraction and ion exchange methods, are being developed. Pyrochemical separation methods, which generate small volumes of aqueous wastes and do not require calcine dissolution, have been evaluated as alternatives to aqueous processes. This report describes three proposed pyrochemical flowsheets and presents the results of experimental studies conducted to evaluate their feasibility. The information presented is a consolidation of three reports, which should be consulted for experimental details

  4. 7 CFR 201.51 - Inert matter.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS Purity Analysis in the Administration of the Act § 201.51 Inert matter. Inert matter shall include... kochia that pass through a 1 mm opening, square-hole sieve, when shaken for 30 seconds. (8) The thin... devoid of the husk and pass through a 1/13th-inch, round-hole sieve. (ii) Bulblets which show evident...

  5. Escoabilidade de leitos de partículas inertes com polpa de frutas tropicais: efeitos na secagem em leito de jorro Flowability of inert particle beds with fruit pulp: effects on the drying in spouted bed

    Directory of Open Access Journals (Sweden)

    Maria de F. D. de Medeiros

    2001-12-01

    Full Text Available Neste trabalho, foram caracterizados seis tipos de material inerte, utilizados na secagem de polpa de frutas em leito de jorro. Determinou-se o ângulo de repouso das partículas, com e sem adição de água e de polpa de diversas frutas tropicais. Correlacionou-se a escoabilidade com as propriedades das partículas e com a composição química das polpas. Analisou-se a influência do ângulo de repouso sobre o desempenho do secador, no que se refere à produção. Os resultados mostraram que, em geral, as polpas com elevadas concentrações de gordura e sólidos insolúveis e baixos teores de açúcares redutores, facilitam a escoabilidade. Uma análise dos resultados obtidos na secagem de polpa de frutas tropicais, utilizando-se partículas de poliestireno de baixa densidade, como material inerte, mostrou que, embora a escoabilidade permita a obtenção de menores vazões de jorro mínimo, em relação ao desempenho do secador, pode não favorecer uma produção maior de pó.In this work six types of inert particles were characterized and analyzed for drying tropical fruit pulps. The repose angle was determined with and without the addition of water and pulp of various tropical fruits. The bed flowability was related to the particle properties and chemical composition of pulps. The influence of the repose angle on the drying performance was analyzed. It was also verified that the composition of pulps influenced the bed flowability. The global analysis showed that the pulps with high lipids and insoluble solids content and low reducing sugar content improved the bed flowability. The results obtained with the drying of the fruit pulps using low-density polystyrene granules as inert particles showed that high flowabilities lead to lower minimum spout flow rates, but do not necessarily lead to the highest powder production.

  6. Inert Reassessment Document for Gluconic Acid and Sodium Salt

    Science.gov (United States)

    Gluconic acid and D-gluconic acid are classified as List 3 inert ingredients, sodium gluconate is classified as a List 4B inert ingredient, and D-gluconic acid, sodium salt has not been categorized as to inert ingredient list classification status.

  7. Thermodynamic approach to the conditions of chemical deposition of boron by contact with an inert substrate

    International Nuclear Information System (INIS)

    Thebault, J.; Naslain, R.; Hagenmuller, P.; Bernard, C.

    1978-01-01

    The optimum conditions for the synthesis of boron by chemical vapour deposition (CVD) from BCl 3 -H 2 or BBr 3 -H 2 mixtures onto an inert substrate (boron or boronized metals) have been studied by a thermodynamic approach. This approach, which postulates that states close to equilibrium are reached in the vicinity of the hot substrate, is based on the minimization of the total Gibbs free energy of the system. Between 1200 and 1900 K and under a total pressure of 1 atm, the hydrogen reduction of BCl 3 can lead to two types of by-products: BHCl 2 at all temperatures, and BCl 2 or BCl subhalides at high temperatures; BHCl 2 is the main product of the reduction at the lowest temperatures. The hydrogen reduction of BCl 3 is never complete for the conditions commonly used for the synthesis of boron. The amount of by-products and of BBr 3 which must be recycled can be minimized by utilizing BCl 3 -H 2 mixtures rich in hydrogen. The amount of boron deposited exhibits a maximum for a temperature close to 1700 K. Similar results have been obtained for BBr 3 . However, between 1000 and 1500 K and under a total pressure of 1 atm the amount of by-products (BHBr 2 and BBr 2 ) is smaller than in the case of BCl 3 . The boron yield from the reduction of BBr 3 is higher than that from BCl 3 and the percentage of boron halide which must be recycled is lower in the case of BBr 3 . Thus, BBr 3 appears to be a better source than BCl 3 for the CVD of boron. (Auth.)

  8. Alternative inerting agents

    CSIR Research Space (South Africa)

    Du

    1997-08-01

    Full Text Available Final Project Report ALTERNATIVE INERTING AGENTS Author/s: J J L DU PLESSIS Research Agency: OSIR MINING TECHNOLOGY Project No: Date: 3 2 7 2 COL 443 APRIL 1999 N’ ) ( G~6~ I Title: 9 / The results show...

  9. Epileptiform activity during inert gas euthanasia of mice.

    Science.gov (United States)

    Gent, Thomas C; Detotto, Carlotta; Vyssotski, Alexei L; Bettschart-Wolfensberger, Regula

    2018-01-01

    Carbon dioxide (CO2) is one of the most commonly used euthanasia agents for mice, yet it is highly aversive and nociceptive. Inert gases are a possible alternative, however there are qualitative reports of seizures resulting from exposure. Here we evaluate epileptiform activity caused by inert gases (N2, He, Ar and Xe) and CO2 in mice chronically instrumented for EEG/EMG undergoing single-gas euthanasia. We found that N2, He and Ar caused epileptiform activity in all animals, CO2 in half of animals and no epileptiform activity produced by Xe. Atmospheric O2 concentrations at epileptiform activity onset were significantly higher for CO2 than for all other gases and occurred soon after loss of motion, whereas N2 and Ar epileptiform activity occurred at cessation of neocortical activity. Helium caused the longest epileptiform activity and these commenced significantly before isoelectric EEG. We did not detect any epileptiform activity during active behaviour. Taken together, these results demonstrate that whilst epileptiform activity from inert gases and particularly Ar and N2 are more prevalent than for CO2, their occurrence at the onset of an isoelectric EEG is unlikely to impact on the welfare of the animal. Epileptiform activity from these gases should not preclude them from further investigation as euthanasia agents. The genesis of epileptiform activity from CO2 is unlikely to result from hypoxia as with the inert gases. Helium caused epileptiform activity before cessation of neocortical activity and for a longer duration and is therefore less suitable as an alternative to CO2.

  10. Inert tracer wind resuspension as a function of wind speed, atmospheric stability, and initial tracer particle size

    International Nuclear Information System (INIS)

    Sehmel, G.A.; Lloyd, F.D.

    1979-01-01

    Wind-caused resuspension rates are being determined in three different, long-term, inert-tracer field experiments. Chemical results were recently received from an accumulated backlog of air filter samples. Resuspension rates are yet to be calculated from these data

  11. Model identification methodology for fluid-based inerters

    Science.gov (United States)

    Liu, Xiaofu; Jiang, Jason Zheng; Titurus, Branislav; Harrison, Andrew

    2018-06-01

    Inerter is the mechanical dual of the capacitor via the force-current analogy. It has the property that the force across the terminals is proportional to their relative acceleration. Compared with flywheel-based inerters, fluid-based forms have advantages of improved durability, inherent damping and simplicity of design. In order to improve the understanding of the physical behaviour of this fluid-based device, especially caused by the hydraulic resistance and inertial effects in the external tube, this work proposes a comprehensive model identification methodology. Firstly, a modelling procedure is established, which allows the topological arrangement of the mechanical networks to be obtained by mapping the damping, inertance and stiffness effects directly to their respective hydraulic counterparts. Secondly, an experimental sequence is followed, which separates the identification of friction, stiffness and various damping effects. Furthermore, an experimental set-up is introduced, where two pressure gauges are used to accurately measure the pressure drop across the external tube. The theoretical models with improved confidence are obtained using the proposed methodology for a helical-tube fluid inerter prototype. The sources of remaining discrepancies are further analysed.

  12. Nanotoxicity of Inert Materials: The Case of Gold, Silver and Iron.

    Science.gov (United States)

    Umair, Muhammad; Javed, Ibrahim; Rehman, Mubashar; Madni, Asadullah; Javeed, Aqeel; Ghafoor, Aamir; Ashraf, Muhammad

    2016-01-01

    Nanotechnology has opened a new horizon of research in various fields including applied physics, chemistry, electronics, optics, robotics, biotechnology and medicine. In the biomedical field, nanomaterials have shown remarkable potential as theranostic agents. Materials which are considered inert are often used in nanomedicine owning to their nontoxic profile. At nanoscale, these inert materials have shown unique properties that differ from bulk and dissolved counterparts. In the case of metals, this unique behavior not only imparts paramount advantages but also confers toxicity due to their unwanted interaction with different cellular processes. In the literature, the toxicity of nanoparticles made from inert materials has been investigated and many of these have revealed toxic potential under specific conditions. The surge to understand underlying mechanism of toxicity has increased and different means have been employed to overcome toxicity problems associated with these agents. In this review, we have focused nanoparticles of three inert metallic materials i.e. gold, silver and iron as these are regarded as biologically inert in the bulk and dissolved form. These materials have gained wider research interest and studies indicating the toxicity of these materials are also emerging. Oxidative stress, physical binding and interference with intracellular signaling are the major role player in nanotoxicity and their predominance is highly dependent upon size, surface coating and administered dose of nanoparticles. Current strategies to overcome toxicity have also been reviewed in the light of recent literature. The authors also suggested that uniform testing standards and well-designed studies are needed to evaluate nanotoxicity of these materials that are otherwise considered as inert. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  13. Trapping of He clusters by inert-gas impurities in tungsten: First-principles predictions and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Manh, Duc, E-mail: duc.nguyen@ccfe.ac.uk; Dudarev, S.L.

    2015-06-01

    Properties of point defects resulting from the incorporation of inert-gas atoms in bcc tungsten are investigated systematically using first-principles density functional theory (DFT) calculations. The most stable configuration for the interstitial neon, argon, krypton and xenon atoms is the tetrahedral site, similarly to what was found earlier for helium in W. The calculated formation energies for single inert-gas atoms at interstitial sites as well as at substitutional sites are much larger for Ne, Ar, Kr and Xe than for He. While the variation of the energy of insertion of inert-gas defects into interstitial configurations can be explained by a strong effect of their large atomic size, the trend exhibited by their substitutional energies is more likely related to the covalent interaction between the noble gas impurity atoms and the tungsten atoms. There is a remarkable variation exhibited by the energy of interaction between inert-gas impurities and vacancies, where a pronounced size effect is observed when going from He to Ne, Ar, Kr, Xe. The origin of this trend is explained by electronic structure calculations showing that p-orbitals play an important part in the formation of chemical bonds between a vacancy and an atom of any of the four inert-gas elements in comparison with helium, where the latter contains only 1s{sup 2} electrons in the outer shell. The binding energies of a helium atom trapped by five different defects (He-v, Ne-v, Ar-v, Kr-v, Xe-v, where v denotes a vacancy in bcc-W) are all in excellent agreement with experimental data derived from thermal desorption spectroscopy. Attachment of He clusters to inert gas impurity atom traps in tungsten is analysed as a function of the number of successive trapping helium atoms. Variation of the Young modulus due to inert-gas impurities is analysed on the basis of data derived from DFT calculations.

  14. Inert Anode Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1999-07-01

    This ASME report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issues associated with these technologies from a technical, environmental, and economic viewpoint.

  15. Inert gas handling in ion plating systems

    International Nuclear Information System (INIS)

    Goode, A.R.; Burden, M.St.J.

    1979-01-01

    The results of an investigation into the best methods for production and monitoring of the inert gas environment for ion plating systems are reported. Work carried out on Pirani gauges and high pressure ion gauges for the measurement of pressures in the ion plating region (1 - 50mtorr) and the use of furnaces for cleaning argon is outlined. A schematic of a gas handling system is shown and discussed. (UK)

  16. Helium in inert matrix dispersion fuels

    International Nuclear Information System (INIS)

    Veen, A. van; Konings, R.J.M.; Fedorov, A.V.

    2003-01-01

    The behaviour of helium, an important decay product in the transmutation chains of actinides, in dispersion-type inert matrix fuels is discussed. A phenomenological description of its accumulation and release in CERCER and CERMET fuel is given. A summary of recent He-implantation studies with inert matrix metal oxides (ZrO 2 , MgAl 2 O 4 , MgO and Al 2 O 3 ) is presented. A general picture is that for high helium concentrations helium and vacancy defects form helium clusters which convert into over-pressurized bubbles. At elevated temperature helium is released from the bubbles. On some occasions thermal stable nano-cavities or nano-pores remain. On the basis of these results the consequences for helium induced swelling and helium storage in oxide matrices kept at 800-1000 deg. C will be discussed. In addition, results of He-implantation studies for metal matrices (W, Mo, Nb and V alloys) will be presented. Introduction of helium in metals at elevated temperatures leads to clustering of helium to bubbles. When operational temperatures are higher than 0.5 melting temperature, swelling and helium embrittlement might occur

  17. 46 CFR 154.908 - Inert gas generator: Location.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inert gas generator: Location. 154.908 Section 154.908 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Atmospheric Control in Cargo Containment Systems § 154.908 Inert gas generator: Location. (a) Except as...

  18. Quantification of the inert chemical oxygen demand of raw wastewater and evaluation of soluble microbial product production in demo-scale upflow anaerobic sludge blanket reactors under different operational conditions.

    Science.gov (United States)

    Aquino, Sergio F; Gloria, Roberto M; Silva, Silvana Q; Chernicharo, Carlos A L

    2009-06-01

    This paper investigates the production of soluble microbial products (SMPs) in demonstration-scale upflow anaerobic sludge blanket reactors operated under different conditions and fed with raw wastewater. The results showed that 9.2 +/- 1.3% of the influent soluble chemical oxygen demand (COD) could be considered inert to anaerobic treatment and that the amount of COD produced by biomass varied from 30 to 70 mg x L(-1), accounting for 45 to 63% of the soluble effluent COD. The accumulation of SMP appeared to be dependent on the hydraulic retention time (HRT) applied to the reactors, with a larger accumulation of SMP observed at the lowest HRT (5 hours); this may have been due to stress conditions caused by high upflow velocity (1.1 m x h(-1)). In terms of residual COD characterization, ultrafiltration results showed that higher amounts of high molecular weight compounds were found when HRT was the lowest (5 hours), and that the molecular weight distribution depended on the operational condition of the reactors. Biodegradability tests showed that the low and high molecular weight SMPs were only partially degraded anaerobically (10 to 60%) and that the high molecular weight SMPs were difficult to degrade aerobically.

  19. Bioactive and inert dental glass-ceramics.

    Science.gov (United States)

    Montazerian, Maziar; Zanotto, Edgar Dutra

    2017-02-01

    The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017. © 2016 Wiley Periodicals, Inc.

  20. Experimental Study of an On-board Fuel Tank Inerting System

    Science.gov (United States)

    Wu, Fei; Lin, Guiping; Zeng, Yu; Pan, Rui; Sun, Haoyang

    2017-03-01

    A simulated aircraft fuel tank inerting system was established and experiments were conducted to investigate the performance of the system. The system uses hollow fiber membrane which is widely used in aircraft as the air separation device and a simplified 20% scale multi compartment fuel tank as the inerting object. Experiments were carried out to investigate the influences of different operating parameters on the inerting effectiveness of the system, including NEA (nitrogen-enriched air) flow rate, NEA oxygen concentration, NEA distribution, pressure of bleeding air and fuel load of the tank. Results showed that for the multi compartment fuel tank, concentrated flow washing inerting would cause great differences throughout the distribution of oxygen concentration in the fuel tank, and inerting dead zone would exist. The inerting effectiveness was greatly improved and the ullage oxygen concentration of the tank would reduce to 12% successfully when NEA entered three compartments evenly. The time span of a complete inerting process reduced obviously with increasing NEA flow rate and decreasing NEA concentration, but the trend became weaker gradually. However, the reduction of NEA concentration will decrease the utilization efficiency of the bleeding air. In addition, the time span can also be reduced by raising the pressure of bleeding air, which will improve the bleeding air utilization efficiency at the same time. The time span decreases linearly as the fuel load increases.

  1. One-loop contributions to neutral minima in the inert doublet model

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, P.M. [Instituto Superior de Engenharia de Lisboa - ISEL,1959-007 Lisboa (Portugal); Centro de Física Teórica e Computacional - FCUL,Universidade de Lisboa, R. Ernesto de Vasconcelos, 1749-016 Lisboa (Portugal); Świeżewska, Bogumiła [Faculty of Physics, University of Warsaw,Pasteura 5, 02-093 Warsaw (Poland)

    2016-04-15

    The vacuum structure of the inert doublet model is analysed at the one-loop level using the effective potential formalism, to verify the validity of tree-level predictions for the properties of the global minimum. An inert minimum (with massive fermions) and an inert-like minimum (with massless fermions) can coexist at tree level. But the one-loop analysis reveals that the allowed parameter space for the coexistence of more than one minimum is larger than the tree-level expected one. It is also shown that for some choices of parameters, the global minimum found at the one-loop level may be inert (or inert-like), contrary to what the tree-level analysis indicates.

  2. Nuclear Technology. Course 28: Welding Inspection. Module 28-3, Tungsten Inert Gas (TIG), Metal Inert Gas (MIG) and Submerged Arc Welding.

    Science.gov (United States)

    Espy, John

    This third in a series of ten modules for a course titled Welding Inspection presents the apparatus, process techniques, procedures, applications, associated defects, and inspection for the tungsten inert gas, metal inert gas, and submerged arc welding processes. The module follows a typical format that includes the following sections: (1)…

  3. Adsorption and desorption of radioactive inert gases in various materials

    International Nuclear Information System (INIS)

    Butkus, D.

    1999-01-01

    Peculiarities of the 85 Kr and 133 Xe adsorption and desorption processes in active carbon and paraffin are considered in the work. During the desorption process, the distribution of 85 Kr and 133 Xe atoms in active carbon particles is uneven: atoms in narrow micropores desorb the last. It is shown that by changing adsorption conditions the presence time of radioactive inert gases in an active carbon can be prolonged. The adsorption and desorption processes change in the adsorbent, which changes its aggregation state: adsorption occurs in a liquid absorbent and desorption - in a solid absorbent. Paraffin is just such an absorbent changing its aggregation state with low energy losses. It has been obtained that 133 Xe accumulates less in liquid paraffin that in an active carbon. The absorption of 85 Kr in paraffin is larger than in an active carbon (at 18-20 degrees Celsius), while desorption is slower. The velocity of radioactive inert gas atom motion in different places of a solid paraffin sample is different - it increases approaching the borders of the sample. Prolongation of the desorption time of radioactive inert gases from adsorbents and adsorbents in many cases is of a practical importance. In this work, it has been shown by model experiments that the intensity of adsorption and desorption processes for the same sorbents can be changed. Desorption intensity changes are related to the distribution of gas atoms on the surface of particles and in micropores. Desorption velocity decreases if inert gas atoms having entered micropores are 'closed' by condensed liquids in the environment. In this case an inert gas atom diffuses within the whole particle volume or through the condensed liquid. Radioactive inert gases 85 Kr and 133 Xe are absorbed not only in liquid paraffin but in solid one as well. Therefore, after a paraffin sample is hermetically closed in a glass dish, 85 Kr (gas) having diffused from this sample is repeatedly absorbed in it. The 85 Kr

  4. Portable spectrometer monitors inert gas shield in welding process

    Science.gov (United States)

    Grove, E. L.

    1967-01-01

    Portable spectrometer using photosensitive readouts, monitors the amount of oxygen and hydrogen in the inert gas shield of a tungsten-inert gas welding process. A fiber optic bundle transmits the light from the welding arc to the spectrometer.

  5. Neutralino dark matter with inert higgsinos and singlinos

    International Nuclear Information System (INIS)

    Hall, Jonathan P.; King, Stephen F.

    2009-01-01

    We discuss neutralino dark matter arising from supersymmetric models with extra inert Higgsinos and singlinos, where inert means that their scalar partners do not get vacuum expectation values. As an example, we consider the extended neutralino sector of the E 6 SSM, which predicts three families of Higgs doublet pairs, plus three singlets, plus a Z', together with their fermionic superpartners. We show that the two families of inert doublet Higgsinos and singlinos predicted by this model provide an almost decoupled neutralino sector with a naturally light LSP which can account for the cold dark matter relic abundance independently of the rest of the model, providing that the ratio of the two usual Higgs doublets satisfies tan β < 2.

  6. Efficiency of inert mineral dusts in the control of corn weevil

    Directory of Open Access Journals (Sweden)

    Carlos F. Jairoce

    2016-02-01

    Full Text Available ABSTRACT Corn weevil (Sitophilus zeamais may cause great losses in the crop and in stored corn grains. This insect is controlled with the use of chemical insecticides, which may cause serious damage to human health. One alternative of control is the use of inert dusts. The objective of this study was to evaluate the efficiency of inert dusts in the control of S. zeamais under laboratory conditions. The experiment was conducted in 2014, in a completely randomized design, and the treatments consisted of basalt dust with three different granulometries (A, B and C and diatomaceous earth, each of which at the doses of 2 and 4 kg t-1 and a control (no application. Each treatment had four replicates, and the sample unit consisted of 20 g of corn grains infected with 10 adults of S. zeamais kept in temperature-controlled chamber at 25 °C, 70% RH and photophase of 12 h. The dust efficiency was calculated using the equation of Abbott. The mortality rate was higher with the use of diatomaceous earth, reaching 100% after 5 days of exposure and the percentage of control for basalt dusts, 29 days after treatment, was above 80%.

  7. TIG (Tungsten Inert Gas) welding

    International Nuclear Information System (INIS)

    Anon.

    2010-01-01

    After having recalled the Tungsten Inert Gas process principle and the different alternative TIG processes, the author explains the advantages and limits of this process. The applications and recent developments are given. (O.M.)

  8. Advanced On Board Inert Gas Generation System (OBBIGS), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Valcor Engineering Corporation proposes to develop an advanced On Board Inert Gas Generation System, OBIGGS, for aircraft fuel tank inerting to prevent hazardous...

  9. Development of high frequency tungsten inert gas welding method

    International Nuclear Information System (INIS)

    Morisada, Yoshiaki; Fujii, Hidetoshi; Inagaki, Fuminori; Kamai, Masayoshi

    2013-01-01

    Highlights: ► A new ultrasonic wave TIG welding method was developed. ► The area of the blowholes decreased to less than about 1/8 in the normal TIG weld. ► The number of blowholes decreased with the decreasing frequency. ► The number of blowholes increased when the frequency was less than 15 kHz. ► The microstructure of the weld was refined by ultrasonic wave. -- Abstract: A new welding method, called high frequency tungsten inert gas (TIG) welding, was developed to decrease blowholes in a weld. A1050 aluminum alloy plates (100 mm l × 50 mm w × 5 mm t ) were welded at a frequency from 10 to 40 kHz. An Ar-1% hydrogen mixture was used as the shielding gas to generate blowholes in the experiments. The welding was performed in the horizontal position so that the blowholes can easily be a problem. For comparison, a normal TIG welding was also performed at 60 Hz. After welding, the distribution of the blowholes in the welds was observed in order to evaluate the effect of the sonic wave. The number of blowholes changed with the frequency. A frequency near 15 kHz is the most suitable to decrease the blowholes. Using this new method, the area of blowholes is decreased to less than about 1/8 of the normal TIG weld. This method is much more effective for decreasing the number of blowholes, compared with an ultrasonic wave vibrator which is directly fixed to the sample.

  10. Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures.

    Science.gov (United States)

    Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

    2016-04-15

    The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Conversion of zircaloy to a massive chemically inert form

    International Nuclear Information System (INIS)

    Atkinson, A.; Kearsey, H.A.; Knibbs, R.H.; Mercer, A.C.; Nickerson, A.K.; Pearson, D.; Sambell, R.A.J.; Taylor, R.I.

    1985-01-01

    The report covers work carried out in the period July 1980 - December 1982 on the development and assessment of an aqueous route for the conversion of Zircaloy fuel element cladding to a stable oxide form and on alternative methods for incorporating the oxide into monolithic waste forms suitable for long-term storage and disposal. The work included two aspects, preliminary process development studies aimed at demonstrating the key steps in the process, and studies on the alternative immobilization techniques and the properties of the resulting waste forms. Experimental studies have shown that the ''hydrous zirconium oxide'' (with a residual fluoride content), following calcination at about 500 0 C, can be hot-pressed at 800-1000 0 C and 22.5 MPa to a high density ceramic waste form with good capacity for the incorporation of active species, such as U 4+ and Sr 2+ , and high leach resistance. Parallel studies have been carried out on the incorporation of the washed ''hydrous zirconium oxide'' in a range of cement matrices. A preliminary chemical engineering assessment of the overall process has been made and flowsheets for a plant to convert 250 kg Zircaloy/day have been prepared

  12. An electromagnetic inerter-based vibration suppression device

    International Nuclear Information System (INIS)

    Gonzalez-Buelga, A; Clare, L R; Neild, S A; Jiang, J Z; Inman, D J

    2015-01-01

    This paper describes how an inerter-based device for structural vibration suppression can be realized using an electromagnetic transducer such as a linear motor. When the motor shaft moves, a difference of voltage is generated across the transducer coil. The voltage difference is proportional to the relative velocity between its two terminals. The electromagnetic transducer will exert a force proportional to current following the Lorentz principle if the circuit is closed around the transducer coil. If an electronic circuit consisting of a capacitor, an inductance and a resistance with the appropriate configuration is connected, the resulting force reflected back into the mechanical domain is equivalent to that achieved by a mechanical inerter-based device. The proposed configuration is easy to implement and very versatile, provided a high quality conversion system with negligible losses. With the use of electromagnetic devices, a new generation of vibration absorbers can be realized, for example in the electrical domain it would be relatively uncomplicated to synthesize multi-frequency or real time tunable vibration absorbers by adding electrical components in parallel. In addition by using resistance emulators in the electrical circuits, part of the absorbed vibration energy can be converted into usable power. Here an electromagnetic tuned inerter damper (E-TID) is tested experimentally using real time dynamic substructuring. A voltage compensation unit was developed in order to compensate for coil losses. This voltage compensation unit requires power, which is acquired through harvesting from the vibration energy using a resistance emulator. A power balance analysis was developed in order to ensure the device can be self sufficient. Promising experimental results, using this approach, have been obtained and are presented in this paper. The ultimate goal of this research is the development of autonomous electromagnetic vibration absorbers, able to harvest energy

  13. Diamond nanostructured devices for chemical sensing applications

    OpenAIRE

    Ahmad, R. K.

    2011-01-01

    Research in the area of CVD single crystal diamond plates of which only recently has been made commercially available saw significant advancements during the last decade. In parallel to that, detonation nanodiamond (DND) particles also now widely made accessible for requisition are provoking a lot of scientific investigations. The remarkable properties of diamond including its extreme hardness, low coefficient of friction, chemical inertness, biocompatibility, high thermal c...

  14. Preliminary Design Report Shippingport Spent Fuel Drying and Inerting System

    International Nuclear Information System (INIS)

    JEPPSON, D.W.

    2000-01-01

    A process description and system flow sheets have been prepared to support the design/build package for the Shippingport Spent Fuel Canister drying and inerting process skid. A process flow diagram was prepared to show the general steps to dry and inert the Shippingport fuel loaded into SSFCs for transport and dry storage. Flow sheets have been prepared to show the flows and conditions for the various steps of the drying and inerting process. Calculations and data supporting the development of the flow sheets are included

  15. Permeation, diffusion and dissolution of hydrogen isotopes, methane and inert gases through/in a tetrafluoroethylene film

    International Nuclear Information System (INIS)

    Matsuyama, M.; Miyake, H.; Ashida, K.; Watanabe, K.

    1982-01-01

    Tetrafluoroethylene (TFE) is widely used for conventional tritium handling systems such as vacuum seals, tubing and so on. We measured the permeation of the three hydrogen isotopes, methane and the inert gases through a TFE film at room temperature by means of the time-lag method in order to establish the physicochemical properties which determine the solubility and diffusivity of those gases. It was found that the diffusion constant of the inert gases changed exponentially with the heat of vaporization and the solubility was an exponential function of the Lennard-Jones force constant of the gases. On the other hand, hydrogen isotopes and methane deviated from these relations. It is concluded that chemical interactions between the solute and the solvent play an important role for the dissolution and the diffusion of these gases in TFE. (orig.)

  16. A scintillation detector for measuring inert gas beta rays

    International Nuclear Information System (INIS)

    Shi Hengchang; Yu Yunchang

    1989-10-01

    The inert gas beta ray scintillation detector, which is made of organic high polymers as the base and coated with compact fluorescence materials, is a lower energy scintillation detector. It can be used in the nuclear power plant and radioactive fields as a lower energy monitor to detect inert gas beta rays. Under the conditions of time constant 10 minutes, confidence level is 99.7% (3σ), the intensity of gamma rays 2.6 x 10 -7 C/kg ( 60 Co), and the minimum detectable concentration (MDC) of this detector for 133 Xe 1.2 Bq/L. The measuring range for 133 Xe is 11.1 ∼ 3.7 x 10 4 Bq/L. After a special measure is taken, the device is able to withstand 3 x 10 5 Pa gauge pressure. In the loss-of-cooolant-accident, it can prevent the radioactive gas of the detector from leaking. This detector is easier to be manufactured and decontaminated

  17. Carbon dioxide as chemical feedstock

    National Research Council Canada - National Science Library

    Aresta, M

    2010-01-01

    ... Dioxide as an Inert Solvent for Chemical Syntheses 15 Alessandro Galia and Giuseppe Filardo Introduction 15 Dense Carbon Dioxide as Solvent Medium for Chemical Processes 15 Enzymatic Catalysis in Dense Carbon Dioxide 18 Other Reactions in Dense Carbon Dioxide 19 Polymer Synthesis in Supercritical Carbon Dioxide 20 Chain Polymerizations: Synt...

  18. Method of enhanced lithiation of doped silicon carbide via high temperature annealing in an inert atmosphere

    Science.gov (United States)

    Hersam, Mark C.; Lipson, Albert L.; Bandyopadhyay, Sudeshna; Karmel, Hunter J; Bedzyk, Michael J

    2014-05-27

    A method for enhancing the lithium-ion capacity of a doped silicon carbide is disclosed. The method utilizes heat treating the silicon carbide in an inert atmosphere. Also disclosed are anodes for lithium-ion batteries prepared by the method.

  19. Capillary-discharge-based portable detector for chemical vapor monitoring

    International Nuclear Information System (INIS)

    Duan Yixiang; Su Yongxuan; Jin Zhe

    2003-01-01

    Conventional portable instruments for sensing chemical vapors have certain limitations for on-site use. In this article, we develop a genuinely portable detector that is sensitive, powerful, rugged, of simple design, and with very low power needs. Such a detector is based on a dry-cell battery-powered, capillary-discharge-based, microplasma source with optical emission detection. The microscale plasma source has very special features such as low thermal temperature and very low power needs. These features make it possible for the plasma source to be powered with a small dry-cell battery. A specially designed discharge chamber with minielectrodes can be configured to enhance the plasma stability and the system performance. A very small amount of inert gas can be used as sample carrier and plasma supporting gas. Inert gases possess high excitation potentials and produce high-energy metastable particles in the plasma. These particles provide sufficient energy to excite chemical species through Penning ionization and/or energy transfer from metastable species. A molecular emission spectrum can be collected with a palm-sized spectrometer through a collimated optical fiber. The spectrum can be displayed on a notebook computer. With this design and arrangement, the new detector provides high sensitivity for organic chemical species. The advantages and features of the newly developed detector include high sensitivity, simple structure, low cost, universal response, very low power consumption, compact volume with field portable capability, and ease of operation

  20. INERT-MATRIX FUEL: ACTINIDE ''BURNING'' AND DIRECT DISPOSAL

    International Nuclear Information System (INIS)

    Rodney C. Ewing; Lumin Wang

    2002-01-01

    Excess actinides result from the dismantlement of nuclear weapons (Pu) and the reprocessing of commercial spent nuclear fuel (mainly 241 Am, 244 Cm and 237 Np). In Europe, Canada and Japan studies have determined much improved efficiencies for burnup of actinides using inert-matrix fuels. This innovative approach also considers the properties of the inert-matrix fuel as a nuclear waste form for direct disposal after one-cycle of burn-up. Direct disposal can considerably reduce cost, processing requirements, and radiation exposure to workers

  1. The Inert and the Noble

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 3. The Inert and the Noble. A G Samuelson. Article-in-a-Box Volume 4 Issue 3 March 1999 pp 3-5 ... Author Affiliations. A G Samuelson1. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India.

  2. Production of inert scalars at the high energy e+e− colliders

    International Nuclear Information System (INIS)

    Hashemi, Majid; Krawczyk, Maria; Najjari, Saereh; Żarnecki, Aleksander Filip

    2016-01-01

    We investigate the phenomenology of the light charged and neutral scalars in Inert Doublet Model at future e + e − colliders with center of mass energies of 0.5 and 1 TeV, and integrated luminosity of 500 fb −1 . The analysis covers two production processes, e + e − →H + H − and e + e − →AH, and consists of signal selections, cross section determinations as well as dark matter mass measurements. Several benchmark points are studied with focus on H ± →W ± H and A→ZH decays. It is concluded that the signal will be well observable in different final states allowing for mass determination of all new scalars with statistical precision of the order of few hundred MeV.

  3. First principles study of inert-gas (helium, neon, and argon) interactions with hydrogen in tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xiang-Shan [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Hou, Jie [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Li, Xiang-Yan [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Wu, Xuebang, E-mail: xbwu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Liu, C.S., E-mail: csliu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Chen, Jun-Ling; Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2017-04-15

    We have systematically evaluated binding energies of hydrogen with inert-gas (helium, neon, and argon) defects, including interstitial clusters and vacancy-inert-gas complexes, and their stable configurations using first-principles calculations. Our calculations show that these inert-gas defects have large positive binding energies with hydrogen, 0.4–1.1 eV, 0.7–1.0 eV, and 0.6–0.8 eV for helium, neon, and argon, respectively. This indicates that these inert-gas defects can act as traps for hydrogen in tungsten, and impede or interrupt the diffusion of hydrogen in tungsten, which supports the discussion on the influence of inert-gas on hydrogen retention in recent experimental literature. The interaction between these inert-gas defects and hydrogen can be understood by the attractive interaction due to the distortion of the lattice structure induced by inert-gas defects, the intrinsic repulsive interaction between inert-gas atoms and hydrogen, and the hydrogen-hydrogen repelling in tungsten lattice.

  4. Chromium liquid waste inertization in an inorganic alkali activated matrix: Leaching and NMR multinuclear approach

    International Nuclear Information System (INIS)

    Ponzoni, Chiara; Lancellotti, Isabella; Barbieri, Luisa; Spinella, Alberto; Saladino, Maria Luisa; Martino, Delia Chillura; Caponetti, Eugenio; Armetta, Francesco; Leonelli, Cristina

    2015-01-01

    Highlights: • Inertization of chromium liquid waste in aluminosilicate matrix. • Water less inertization technique exploiting the waste water content. • Liquid waste inertization without drying step. • Long term stabilization study through leaching test. • SEM analysis and 29 Si and 27 Al MAS NMR in relation with long curing time. - Abstract: A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process - from the precursor dissolution to the final geopolymer matrix hardening - of different geopolymers containing a waste amount ranging from 3 to 20% wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of T−O−T bonds (where T is Al or Si) by 29 Si and 27 Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for geopolymers

  5. Chromium liquid waste inertization in an inorganic alkali activated matrix: Leaching and NMR multinuclear approach

    Energy Technology Data Exchange (ETDEWEB)

    Ponzoni, Chiara, E-mail: chiara.ponzoni@unimore.it [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy); Lancellotti, Isabella; Barbieri, Luisa [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy); Spinella, Alberto; Saladino, Maria Luisa [University of Palermo CGA-UniNetLab, Palermo (Italy); Martino, Delia Chillura [University of Palermo, Department STEBICEF, Palermo (Italy); Caponetti, Eugenio [University of Palermo CGA-UniNetLab, Palermo (Italy); University of Palermo, Department STEBICEF, Palermo (Italy); Armetta, Francesco [University of Palermo, Department STEBICEF, Palermo (Italy); Leonelli, Cristina [University of Modena and Reggio Emilia, Department of Engineering “Enzo Ferrari”, Modena (Italy)

    2015-04-09

    Highlights: • Inertization of chromium liquid waste in aluminosilicate matrix. • Water less inertization technique exploiting the waste water content. • Liquid waste inertization without drying step. • Long term stabilization study through leaching test. • SEM analysis and {sup 29}Si and {sup 27}Al MAS NMR in relation with long curing time. - Abstract: A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process - from the precursor dissolution to the final geopolymer matrix hardening - of different geopolymers containing a waste amount ranging from 3 to 20% wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of T−O−T bonds (where T is Al or Si) by {sup 29}Si and {sup 27}Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for

  6. Comparative Study between Two Schemes of Active-Control-Based Mechatronic Inerter

    Directory of Open Access Journals (Sweden)

    He Lingduo

    2017-01-01

    Full Text Available Based on force-current analogy and velocity-voltage analogy in the theory of electromechanical analogy, the inerter is a device that corresponded to the capacitor completely where conquers the nature restriction of mass, what’s more, it is significant to improve the ratio of the inerter’s inertance to its mass for mechanical networks synthesis. And according to the principle of active-control-based mechatronic inerter, we present two implementation schemes. One was based on linear motor, and the other was based on the ball screw and rotary motor. We introduced the implementation methods and established theoretical model of the two schemes, then compared the ratio of the inerter’s inertance to its mass for the two schemes. Finally, we consider the scheme is better which was based on the ball screw and rotary motor.

  7. Chemical Sharpening, Shortening, and Unzipping of Boron Nitride Nanotubes

    Science.gov (United States)

    Liao, Yunlong; Chen, Zhongfang; Connell, John W.; Fay, Catharine C.; Park, Cheol; Kim, Jae-Woo; Lin, Yi

    2014-01-01

    Boron nitride nanotubes (BNNTs), the one-dimensional member of the boron nitride nanostructure family, are generally accepted to be highly inert to oxidative treatments and can only be covalently modifi ed by highly reactive species. Conversely, it is discovered that the BNNTs can be chemically dispersed and their morphology modifi ed by a relatively mild method: simply sonicating the nanotubes in aqueous ammonia solution. The dispersed nanotubes are significantly corroded, with end-caps removed, tips sharpened, and walls thinned. The sonication treatment in aqueous ammonia solution also removes amorphous BN impurities and shortened BNNTs, resembling various oxidative treatments of carbon nanotubes. Importantly, the majority of BNNTs are at least partially longitudinally cut, or "unzipped". Entangled and freestanding BN nanoribbons (BNNRs), resulting from the unzipping, are found to be approximately 5-20 nm in width and up to a few hundred nanometers in length. This is the fi rst chemical method to obtain BNNRs from BNNT unzipping. This method is not derived from known carbon nanotube unzipping strategies, but is unique to BNNTs because the use of aqueous ammonia solutions specifi cally targets the B-N bond network. This study may pave the way for convenient processing of BNNTs, previously thought to be highly inert, toward controlling their dispersion, purity, lengths, and electronic properties.

  8. Inert dusts and their effects on the poultry red mite (Dermanyssus gallinae)

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2009-01-01

    commonly applied alternative control methods for poultry red mite in Europe. This development has occurred despite a lack of knowledge of the efficacy of the different types of inert dusts and how this is affected by environmental parameters, e.g. the high relative humidity found in poultry houses....... In this laboratory study the efficacy of different commercial inert dust products against D. gallinae is compared. All tested compounds killed mites, but there was a clear ranking of efficacy (measured as weight loss after 24 h and as time until 50% mortality), particularly at 75% relative humidity (RH). At 85% RH...

  9. Reducing Actinide Production Using Inert Matrix Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Deinert, Mark [Colorado School of Mines, Golden, CO (United States)

    2017-08-23

    The environmental and geopolitical problems that surround nuclear power stem largely from the longlived transuranic isotopes of Am, Cm, Np and Pu that are contained in spent nuclear fuel. New methods for transmuting these elements into more benign forms are needed. Current research efforts focus largely on the development of fast burner reactors, because it has been shown that they could dramatically reduce the accumulation of transuranics. However, despite five decades of effort, fast reactors have yet to achieve industrial viability. A critical limitation to this, and other such strategies, is that they require a type of spent fuel reprocessing that can efficiently separate all of the transuranics from the fission products with which they are mixed. Unfortunately, the technology for doing this on an industrial scale is still in development. In this project, we explore a strategy for transmutation that can be deployed using existing, current generation reactors and reprocessing systems. We show that use of an inert matrix fuel to recycle transuranics in a conventional pressurized water reactor could reduce overall production of these materials by an amount that is similar to what is achievable using proposed fast reactor cycles. Furthermore, we show that these transuranic reductions can be achieved even if the fission products are carried into the inert matrix fuel along with the transuranics, bypassing the critical separations hurdle described above. The implications of these findings are significant, because they imply that inert matrix fuel could be made directly from the material streams produced by the commercially available PUREX process. Zirconium dioxide would be an ideal choice of inert matrix in this context because it is known to form a stable solid solution with both fission products and transuranics.

  10. Transformation of a beta gamma hot-cell under air in a tight hot-cell under inert gas

    International Nuclear Information System (INIS)

    Lambert, G.

    1981-05-01

    For several years now, fuel elements from graphite gas reactors have been stored in pools at the Cadarache Center after having been subjected (in general) to laboratory examinations. The CEA has adopted the following re-transfer procedure for these fuel elements while awaiting reprocessing: the fuel elements are extracted from their existing cartridges and transferred into new welded stainless steel containers capable of assuring long term storage. The storage, however, envisaged is temporary and is realized in the Pegase pool, specially adapted for this purpose. This re-transfer operation is envisaged for some 2.300 containers. All the appropriate safety measures will be taken. The various different fuel materials handled are often highly irradiated. The presence of water in certain containers due to loss of leaktightness has led to a series of chemical reactions (corrosion of uranium by water, reactions with magnesium, formation of hydrides). As a result, existing envelopes can contain UO 2 , UH 3 and hydrogen; operations must therefore being carried out in an inert atmosphere (preferably argon). The re-transfer process can not therefore be carried out in a conventional cell. It is therefore envisaged to carry out this work in a leaktight cell in an inert atmosphere. A laboratory cell could be modified to perform these functions. This cell would be reconverted to its original state when operations terminate (in about 3 years time) [fr

  11. Biological Activation of Inert Ceramics: Recent Advances Using Tailored Self-Assembled Monolayers on Implant Ceramic Surfaces

    Science.gov (United States)

    Böke, Frederik; Schickle, Karolina; Fischer, Horst

    2014-01-01

    High-strength ceramics as materials for medical implants have a long, research-intensive history. Yet, especially on applications where the ceramic components are in direct contact with the surrounding tissue, an unresolved issue is its inherent property of biological inertness. To combat this, several strategies have been investigated over the last couple of years. One promising approach investigates the technique of Self-Assembled Monolayers (SAM) and subsequent chemical functionalization to create a biologically active tissue-facing surface layer. Implementation of this would have a beneficial impact on several fields in modern implant medicine such as hip and knee arthroplasty, dental applications and related fields. This review aims to give a summarizing overview of the latest advances in this recently emerging field, along with thorough introductions of the underlying mechanism of SAMs and surface cell attachment mechanics on the cell side. PMID:28788687

  12. Method of producing hydrogen, and rendering a contaminated biomass inert

    Science.gov (United States)

    Bingham, Dennis N [Idaho Falls, ID; Klingler, Kerry M [Idaho Falls, ID; Wilding, Bruce M [Idaho Falls, ID

    2010-02-23

    A method for rendering a contaminated biomass inert includes providing a first composition, providing a second composition, reacting the first and second compositions together to form an alkaline hydroxide, providing a contaminated biomass feedstock and reacting the alkaline hydroxide with the contaminated biomass feedstock to render the contaminated biomass feedstock inert and further producing hydrogen gas, and a byproduct that includes the first composition.

  13. Thermodynamic stability and kinetic inertness of a Gd-DTPA bisamide complex grafted onto gold nanoparticles.

    Science.gov (United States)

    Mogilireddy, Vijetha; Déchamps-Olivier, Isabelle; Alric, Christophe; Laurent, Gautier; Laurent, Sophie; Vander Elst, Luce; Muller, Robert; Bazzi, Rana; Roux, Stéphane; Tillement, Olivier; Chuburu, Françoise

    2015-01-01

    Gold nanoparticles coated by gadolinium (III) chelates (Au@DTDTPA) where DTDTPA is a dithiolated bisamide derivative of diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA), constituted contrast agents for both X-ray computed tomography and magnetic resonance imaging. In an MRI context, highly stable Gd(3+) complexes are needed for in vivo applications. Thus, knowledge of the thermodynamic stability and kinetic inertness of these chelates, when grafted onto gold nanoparticles, is crucial since bisamide DTPA chelates are usually less suited for Gd(3+) coordination than DTPA. Therefore, these parameters were evaluated by means of potentiometric titrations and relaxivity measurements. The results showed that, when the chelates were grafted onto the nanoparticle, not only their thermodynamic stability but also their kinetic inertness were improved. These positive effects were correlated to the chelate packing at the nanoparticle surface that stabilized the corresponding Gd(3+) complexes and greatly enhanced their kinetic inertness. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Passive and active vibration isolation systems using inerter

    Science.gov (United States)

    Alujević, N.; Čakmak, D.; Wolf, H.; Jokić, M.

    2018-03-01

    This paper presents a theoretical study on passive and active vibration isolation schemes using inerter elements in a two degree of freedom (DOF) mechanical system. The aim of the work is to discuss basic capabilities and limitations of the vibration control systems at hand using simple and physically transparent models. Broad frequency band dynamic excitation of the source DOF is assumed. The purpose of the isolator system is to prevent vibration transmission to the receiving DOF. The frequency averaged kinetic energy of the receiving mass is used as the metric for vibration isolation quality. It is shown that the use of inerter element in the passive vibration isolation scheme can enhance the isolation effect. In the active case, a feedback disturbance rejection scheme is considered. Here, the error signal is the receiving body absolute velocity which is directly fed to a reactive force actuator between the source and the receiving bodies. In such a scheme, the so-called subcritical vibration isolation problems exist. These problems are characterised by the uncoupled natural frequency of the receiving body larger than the uncoupled natural frequency of the source body. In subcritical vibration isolation problems, the performance of the active control is limited by poor stability margins. This is because the stable feedback gain is restricted in a narrow range between a minimum and a maximum. However, with the inclusion of an inerter in the isolator, one of the two stability margins can be opened. This enables large, theoretically unlimited negative feedback gains and large active damping of the receiving body vibration. A simple expression for the required inertance is derived.

  15. Inert carrier drying and coating process

    International Nuclear Information System (INIS)

    1980-01-01

    An inert carrier process is described for drying radioactive (particularly low level) waste material and for incorporating the dry material into a binder matrix from which the dried material will not be leached. Experimental details, and examples of the carrier and binder materials, are given. (U.K.)

  16. temperature fluctuation inside inert atmosphere silos

    African Journals Online (AJOL)

    ... the two silos for twenty-eight (28) months of storage were recorded in order to monitor temperature fluctuation at different sections inside the inert atmosphere silos loaded with two varieties of wheat namely LACRIWHT-2 (Cettia) and LACRIWHT-4 (Atilla-Gan-Atilla) from Lake Chad Research Institute, Maiduguri, Nigeria.

  17. Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

    Science.gov (United States)

    Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

    2013-01-01

    The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to

  18. Techniques for optimizing inerting in electron processors

    International Nuclear Information System (INIS)

    Rangwalla, I.J.; Korn, D.J.; Nablo, S.V.

    1993-01-01

    The design of an ''inert gas'' distribution system in an electron processor must satisfy a number of requirements. The first of these is the elimination or control of beam produced ozone and NO x which can be transported from the process zone by the product into the work area. Since the tolerable levels for O 3 in occupied areas around the processor are 3 in the beam heated process zone, or exhausting and dilution of the gas at the processor exit. The second requirement of the inerting system is to provide a suitable environment for completing efficient, free radical initiated addition polymerization. The competition between radical loss through de-excitation and that from O 2 quenching must be understood. This group has used gas chromatographic analysis of electron cured coatings to study the trade-offs of delivered dose, dose rate and O 2 concentrations in the process zone to determine the tolerable ranges of parameter excursions for production quality control purposes. These techniques are described for an ink coating system on paperboard, where a broad range of process parameters have been studied (D, D radical, O 2 ). It is then shown how the technique is used to optimize the use of higher purity (10-100 ppm O 2 ) nitrogen gas for inerting, in combination with lower purity (2-20,000 ppm O 2 ) non-cryogenically produced gas, as from a membrane or pressure swing adsorption generators. (author)

  19. A purification process for an inert gas system

    International Nuclear Information System (INIS)

    Raj, S.S.; Samanta, S.K.; Jain, N.G.; Deshingkar, D.S.; Ramaswamy, M.

    1984-01-01

    Special inert atmosphere is desired inside hot cells used for handling radioactive materials. In this report, details of experiments conducted to generate data required for the design of a system for maintaining very low levels of organic and acid vapours, oxygen and moisture in a nitrogen gas inert atmosphere, are described. Several grades of activated charcoals impregnated with 1% KOH were studied for the adsorption of acidic and organic vapours. A Pd/Al 2 O 3 catalyst was developed to remove oxygen with greater than 90% efficiency. For the removal of moisture, a regenerable molecular sieve 4A dual-bed was provided. Based on the performance data thus generated, an integrated purification system for nitrogen gas is proposed. (author)

  20. Preparation of mesoporous zirconia microspheres as inert matrix

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Ting [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Wang, Chen; Lv, Jinlong [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Liang, Tongxiang, E-mail: txliang@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2016-12-01

    Mesoporous zirconia microspheres, with a diameter of 900 μm, were prepared as an inert accelerator driven system (ADS) transmutation element matrix by the sol-gel method. The purpose of mesopores is to improve the adsorption capacity of inert matrix fuel (IMF) for minor actinides. The study indicated that the mesoporous zirconia performance was improved after the microspheres were hydrothermally treated at 150 °C, the specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g, and hydrothermal treatment avoided the cracking of the microspheres. Pre-decomposition of the organics during the hydrothermal process stabilized the mesoporous structure. The average pore diameter of mesoporous microsphere was 14.3 nm. - Highlights: • Mesoporous zirconia microspheres with a diameter of 900 μm were prepared as ADS transmutation element inert matrix. • The mesoporous performance was improved after the microspheres were hydrothermally treated at 150 °C. • The specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g. • The hydrothermal treatment could avoid the cracking of the microspheres. • The specific surface area of mesoporous microsphere was 61.28 m{sup 2}/g and the average pore diameter was 14.3 nm.

  1. Radiochemical and inert gas analyses

    International Nuclear Information System (INIS)

    Andrews, J.N.

    1985-01-01

    The subject is discussed under the headings: introduction (radioelement solution in groundwaters; U and Th; Ra and Rn; atmospheric and radiogenic solution in groundwaters; atmosphere derived gases; radiogenic helium; radiogenic argon; biogenic gases); analytical methods (sampling; U-content and 234 U/ 238 U activity ratio; 222 Ru; 226 Ra; dissolved inert gases; 4 He in core samples); the gamma spectrometric determination of U,Th and K. Results are presented and discussed. (U.K.)

  2. Ethanol Dehydration by Evaporation and Diffusion in an Inert Gas Layer

    Energy Technology Data Exchange (ETDEWEB)

    In-Sick, Chung; Kyu-Min, Song [Korea Advanced Institute of Science and Technology, Taejeon (Korea, Republic of); Won-Hi, Hong; Ho-Nam, Chang [Korea Advanced Institute of Science and Technology, Taejeon (Korea, Republic of)

    1994-08-01

    Ethanol dehydration of azeotropic mixture was performed by using diffusion distillation apparatus consisting of a wetted-wall column with two concentric tubes. Ethanol-water mixtures evaporated below the boiling point was separated during the diffusion through the gap filled with an inert gas. As the temperature difference between evaporation part and condensation part was increased, the total flux increased but the selectivity decreased. The effect of the annular width on the selectivity was not significant but the total flux was decreased with decreases in the annular width. Inert gas has an effect on the diffusivity of evaporated gas components. The total flux in case of helium as inert gas was larger than that in case of air but the selectivity in case of using helium was lower. (author). 14 refs. 1 tab. 12 figs.

  3. Inerting of a Vented Aircraft Fuel Tank Test Article with Nitrogen-Enriched Air

    National Research Council Canada - National Science Library

    Burns, Michael

    2001-01-01

    ...) required to inert a vented aircraft fuel tank. NEA, generated by a hollow fiber membrane gas separation system, was used to inert a laboratory fuel tank with a single vent on top designed to simulate a transport category airplane fuel tank...

  4. Ignition of a reactive solid by an inert hot spot

    OpenAIRE

    Liñán Martínez, Amable; Kindelan Gómez, Manuel

    1981-01-01

    A theoretical analysis is presented for the description of the ignition of a reactive media by inert hot bodies of finite size, when the activation energy of the reaction is large. The analysis leads to closed-form relations for the minimum "critical" size of the hot spot resulting in ignition and for the ignition time by hot spots of supercritical size. The analysis is carried out, first, for inert spots with heat conductivities and diff usivities of the order of those of the reactive media,...

  5. Combustion driven NF3 chemical laser

    International Nuclear Information System (INIS)

    1975-01-01

    Stable, inert, non-corrosive nitrogen trifluoride gas and an inorganic source of hydrogen or deuterium gas are used as reactants in a compact combustion driven chemical laser. Nitrogen trifluoride is introduced into the combustion chamber of a chemical laser together with a hydrogen source selected from hydrogen, hydrazine, ammonia, acetylene, or benzene and the deuterated isotopes thereof and an optional inert diluent gas wherein the nitrogen trifluoride and the hydrogen- or deuterium-source gas hypergolically reacted upon heating to initiation temperature. Dissociated products from the reaction pass into a laser cavity at supersonic velocities where they are reacted with a source gas which is the isotopic opposite of the gas introduced into the combustor and which has been heated by regenerative cooling. Excited molecules of hydrogen fluoride or deuterium fluoride produce laser radiation which leaves the optical resonator cavity transversely to the flow of gases

  6. Estimation of radiation exposure associated with inert gas radionuclides discharged to the environment by the nuclear power industry

    International Nuclear Information System (INIS)

    Bryant, P.M.; Jones, J.A.

    1973-05-01

    Several fission product isotopes of krypton and xenon are formed during operation of nuclear power stations, while other radioactive inert gases, notably isotopes of argon and nitrogen, are produced as neutron activation products. With the exception of 85 Kr these radionuclides are short-lived, and the containment and hold-up arrangements in different reactor systems influence the composition of the inert gas mixtures discharged to the environment. Cooling of irradiated fuel before chemical reprocessing reduces very substantially the amounts of the short-lived krypton and xenon isotopes available for discharge at reprocessing plants, but almost all the 85 Kr formed in the fuel is currently discharged to atmosphere from these plants. Estimates are made of the radiation exposure of the public associated with these discharges to atmosphere taking into account the type of radiation emitted, radioactive half-life and the local, regional and world-wide populations concerned. Such estimates are often based on simple models in which activity is assumed to be distributed in a semi-infinite cloud. The model used in this assessment takes into account the finite cloud near the point of its discharge and its behaviour when dispersion in the atmosphere is affected by the presence of buildings. This is particularly important in the case of discharges from those reactors which do not have high stacks. The model also provides in detail for the continued world-wide circulation of the longer-lived 85 Kr. (author)

  7. Aluminothermic Reduction-Molten Salt Electrolysis Using Inert Anode for Oxygen and Al-Base Alloy Extraction from Lunar Soil Simulant

    Science.gov (United States)

    Xie, Kaiyu; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2017-10-01

    Aluminothermic reduction-electrolysis using an inert anode process is proposed to extract oxygen and metals from Minnesota Lunar Simulant-1 (MLS-1). Effective aluminothermic reduction between dissolved MLS-1 and dissolved metal aluminum was achieved in cryolite salt media. The product phases obtained by aluminothermic reduction at 980°C for 4 h were Al, Si, and Al5FeSi, while the chemical components were 79.71 mass% aluminum, 12.03 mass% silicon, 5.91 mass% iron, and 2.35 mass% titanium. The cryolite salt containing Al2O3 was subsequently electrolyzed with Fe0.58-Ni0.42 inert anode at 960°C for 4 h. Oxygen was evolved at the anode with an anodic current efficiency of 78.28%. The results demonstrate that this two-step process is remarkably feasible for the extraterrestrial extraction of oxygen and metals. This process will help expand the existing in situ resource utilization methods.

  8. TIG (Tungsten Inert Gas) welding; Le soudage TIG

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-09-15

    After having recalled the Tungsten Inert Gas process principle and the different alternative TIG processes, the author explains the advantages and limits of this process. The applications and recent developments are given. (O.M.)

  9. Photoinduced C-C Cross-Coupling of Aryl Chlorides and Inert Arenes

    Directory of Open Access Journals (Sweden)

    Lele Wang

    2016-01-01

    Full Text Available Here we report a facile, efficient, and catalyst-free method to realize C-C cross-coupling of aryl chlorides and inert arenes under UV light irradiation. The aryl radical upon homolytic cleavage of C-Cl bond initiated the nucleophilic substitution reaction with inert arenes to give biaryl products. This mild reaction mode can also be applied to other synthetic reactions, such as the construction of C-N bonds and trifluoromethylated compounds.

  10. Performances of continuous dryer with inert medium fluidized bed

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana Lj.

    2008-01-01

    Full Text Available A fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies according to the main efficiency criteria, i.e. specific water evaporation rate, specific heat consumption and speci­fic air consumption. A high drying efficiency results from the large con­tact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles leads to nearly isothermal conditions throughout the bed. A fluid bed dryer with inert particles was used for drying of slurries. Experiments were performed in a cylindrical column 215 mm in diameter with glass spheres as inert particles. In this paper, results of drying experi­ments with slurries of Zineb fungicide, copper hydroxide, calcium carbo­nate and pure water used as the feed material are presented. In our fluidized bed we successfully dried a number of other materials such as: fungicides and pesticides (Ziram, Propineb, Mangozeb, copper oxy-chloride, copper oxy-sulphate, Bordeaux mixture, other inorganic compounds (calcium sulphate, cobalt carbonate, electrolytic copper, sodium chloride, and a complex compound (organo-bentonite. The effects of operating conditions on dryer throughput and product quality were investigated. Main performance criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption, were quantified. Temperature profile along the bed was mapped, and nearly isothermal conditions were found due to thorough mixing of the particles. Analysis of drying and energy efficiencies as a function of inlet and outlet air temperature difference was performed for deeper insight in dryer behavior and for optimizing dryer design and operation from an energy point of view. A simple mathematical model based on an overall heat balance predicts the dryer performance quite well. The industrial prototype with fluid bed of 0.8 m in diameter and capacity 650 kg of evaporated moisture per

  11. Inerting ballast tanks

    Energy Technology Data Exchange (ETDEWEB)

    Baes, Gabriel L.; Bronneberg, Jos [SBM Offshore, AA Schiedam (Netherlands); Barros, Maria A.S.D. de [Universidade Estadual de Maringa (UEM), PR (Brazil)

    2012-07-01

    This report expands upon the work conducted by SBM Offshore to develop a tank preservation treatment, which is intended to achieve a service life of 30 years. This work focuses on the corrosion problems, in the ballast tanks, based on new built hulls, both for the Gas Exploration Market, the FLNG - Floating Liquefied Natural Gas, and for the Oil Exploration market - FPSO's - Floating Production Storage and offloading Units. Herein, the corrosion rate input comes from the various references related to the process of nitrogen injection, which is expected to extend the vessel's time life. The essential elements of this solution comprise the deoxygenation process, corrosion models, coating effects, tests from laboratory, shipboard tests, corrosion institutes and regulations applicable to the operation. The best corrosion protection system for ballast tanks area combines a coating system and an inert gas system. The condition of the tanks will be dependent upon the level of protection applied to the steel structure, including, but not limited to coating, cathodic protection, etc. There is a need for products which extend the life time. It is not sufficient, only have good theoretical base for the corrosion and an excellent treatment system. In addition, the design of the ships structure must also eliminate the presence of local stress concentrations which can result in fatigue cracking and rupture of the protective coating barrier starting the corrosion. As a direct result of this, more problems in corrosion can be mitigated, vessels can have a better corrosion performance with less maintenance and repairs to coating systems in ballast tanks. Furthermore ships will be positively impacted operationally due to less frequent dry docking. There is a huge potential in the application of inert gas to combat the corrosion rate inside the ballast tanks, one of the most corrosive environments on earth. This application can have a direct impact on vessel structure

  12. Solvent-extraction methods applied to the chemical analysis of uranium. III. Study of the extraction with inert solvents

    International Nuclear Information System (INIS)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement Eguiluz, J. C.

    1964-01-01

    The extraction of uranium on the trace level is studied by using tributylphosphate as active agent under conditions aiming the attainment of quantitative extraction by means of a single step process using a number of salting-out agents and keeping inside the general lines as reported in two precedent papers. Two inert solvents were investigated, benzene and cyclohexane, which allowed to derive the corresponding empirical equations describing the extraction process and the results obtained were compared with those previously reported for solvents which, like ethyl acetate and methylisobuthylketone, favour to a more or less extend the extraction of uranium. (Author) 4 refs

  13. Testes de toxicidade aguda através de bioensaios no extrato solubilizado dos resíduos classe II A - não inertes e classe II B - inertes Acute toxicity tests by bioassays applied to the solubilized extracts of solid wastes class II A - non inerts and class II B - inerts

    Directory of Open Access Journals (Sweden)

    Nébora Liz Vendramin Brasil Rodrigues

    2007-03-01

    Full Text Available A grande diversidade de substâncias potencialmente tóxicas contribuem para a deterioração do meio ambiente. O objetivo deste trabalho foi propor a utilização de bioensaios, através de testes de toxicidade aguda com Daphnia magna e Vibrio fischeri, como mais um parâmetro a ser analisado no extrato solubilizado dos resíduos que, segundo a NBR 10004/04 fossem classificados como classe II A - não inertes ou classe II B - inertes. Realizaram-se, também, testes de toxicidade no drenado dos aterros classe II A e II B. Verificou-se que a toxicidade foi constatada nos extratos solubilizados dos 18 resíduos analisados e que, apenas três das amostras estariam próprias para lançamento, ou seja os resíduos 04, 14 e 15. Já, a toxicidade encontrada no drenado dos aterros, ficou muito superior do que a toxicidade de cada extrato solubilizado analisado separadamente.A great diversity of substances potencially toxic contributes to the deterioration of the environment. The aim of this research was to propose the use of bioassays using Daphnia magna and Vibrio fischeri, as another parameter to be analyzed in the solubilized extraction of waste according to NBR 10004/04 and classified as class II A - non inerts or class II B - inerts. Besides, another test was performed to measure the level of toxicity in the drainage of the landfill class II A and II B. It was verified that the toxicity found in the solubilized extracts of the 18 wastes analysed.Only 3 wastes (04, 14 and 15 were within the emission limits. On the other hand the toxicity found in the drainage of the landfill, from which all the samples came from, was much higher than the individual one.

  14. Numerical analysis on hydrogen stratification and post-inerting of hydrogen risk

    International Nuclear Information System (INIS)

    Peng, Cheng; Tong, Lili; Cao, Xuewu

    2016-01-01

    Highlights: • A three-dimensional computational model was built and the applicability was discussed. • The formation of helium stratification was further studied. • Three influencing factors on the post-inerting of hydrogen risk were analyzed. - Abstract: In the case of severe accidents, the risk of hydrogen explosion threatens the integrity of the nuclear reactor containment. According to nuclear regulations, hydrogen control is required to ensure the safe operation of the nuclear reactor. In this study, the method of Computational Fluid Dynamics (CFD) has been applied to analyze process of hydrogen stratification and the post-inerting of hydrogen risk in the Large-Scale Gas Mixing Facility. A three-dimensional computational model was built and the applicability of different turbulence models was discussed. The result shows that the helium concentration calculated by the standard k–ε turbulence model is closest to the experiment data. Through analyzing the formation of helium stratification at different injection velocities, it is found that when the injection mass flow is constant and the injection velocity of helium increases, the mixture of helium and air is enhanced while there is rarely influence on the formation of helium stratification. In addition, the influences of mass flow rate, injection location and direction and inert gas on the post-inerting of hydrogen risk have been analyzed and the results are as follows: with the increasing of mass flow rate, the mitigation effect of nitrogen on hydrogen risk will be further improved; there is an obvious local difference between the mitigation effects of nitrogen on hydrogen risk in different injection directions and locations; when the inert gas is injected at the same mass flow rate, the mitigation effect of steam on hydrogen risk is better than that of nitrogen. This study can provide technical support for the mitigation of hydrogen risk in the small LWR containment.

  15. Mixed Inert scalar triplet dark matter, radiative neutrino masses and leptogenesis

    Directory of Open Access Journals (Sweden)

    Wen-Bin Lu

    2017-11-01

    Full Text Available The neutral component of an inert scalar multiplet with hypercharge can provide a stable dark matter particle when its real and imaginary parts have a splitting mass spectrum. Otherwise, a tree-level dark-matter-nucleon scattering mediated by the Z boson will be much above the experimental limit. In this paper we focus on a mixed inert scalar triplet dark matter scenario where a complex scalar triplet with hypercharge can mix with another real scalar triplet without hypercharge through their renormalizable coupling to the standard model Higgs doublet. We consider three specified cases that carry most of the relevant features of the full parameter space: (i the neutral component of the real triplet dominates the dark matter particle, (ii the neutral component of the complex triplet dominates the dark matter particle; and (iii the neutral components of the real and complex triplets equally constitute the dark matter particle. Subject to the dark matter relic abundance and direct detection constraint, we perform a systematic study on the allowed parameter space with particular emphasis on the interplay among triplet-doublet terms and gauge interactions. In the presence of these mixed inert scalar triplets, some heavy Dirac fermions composed of inert fermion doublets can be utilized to generate a tiny Majorana neutrino mass term at one-loop level and realize a successful leptogenesis for explaining the cosmic baryon asymmetry.

  16. Some results on development, irradiation and post-irradiation examinations of fuels for fast reactor-actinide burner (MOX and inert matrix fuel)

    International Nuclear Information System (INIS)

    Poplavsky, V.; Zabudko, L.; Moseev, L.; Rogozkin, B.; Kurina, I.

    1996-01-01

    Studies performed have shown principal feasibility of the BN-600 and BN-800 cores to achieve high efficiency of Pu burning when MOX fuel with Pu content up to 45% is used. Valuable experience on irradiation behaviour of oxide fuel with high Pu content (100%) was gained as a result of operation of two BR-10 core loadings where the maximum burnup 14 at.% was reached. Post-irradiation examination (PIE) allowed to reveal some specific features of the fuel with high plutonium content. Principal irradiation and PIE results are presented in the paper. Use of new fuel without U-238 provides the maximum burning capability as in this case the conversion ratio is reduced to zero. Technological investigations of inert matrix fuels have been continued now. Zirconium carbide, zirconium nitride, magnesium oxide and other matrix materials are under consideration. Inert matrices selection criteria are discussed in the paper. Results of technological study, of irradiation in the BOR-60 reactor and PIE results of some inert matrix fuels are summarized in this report. (author). 2 refs, 1 fig., 3 tabs

  17. AGENTES INERTES PARA CONTOLE DE TOMBAMENTO EM SEMENTEIRAS DE OLERÍCOLAS

    Directory of Open Access Journals (Sweden)

    Ricardo Silveiro Balardin

    1994-01-01

    Full Text Available RESUMO Este trabalho foi conduzido com o objetivo de avaliar o comportamento de materiais inertes para controle de tombamento durante a emergência. Os tratamentos foram cobertura do sulco de semeadura com areia e serragem, tratamento químico com brometo de metila e uma testemunha. Os parâmetros avaliados foram percentagem e velocidade de emergência, percentagem de tombamento de pré e pós-emergência. Os dados obtidos permitiram concluir que, dentre os materiais inertes testados, a areia pode constituir-se em uma alternativa eficiente no controle do tombamento em sementeiras de repolho e beterraba, pois permitiu o maior número de plântulas emergidas e o menor número de plântulas tombadas não alterando a velocidade de emergência, enquanto que nas sementeiras de alface a utilização dos materiais inertes prejudicou a emergência normal das plântulas, não se constituindo em agente de controle eficiente.

  18. Inert gas thrusters

    Science.gov (United States)

    Kaufman, H. R.; Robinson, R. S.

    1980-01-01

    Some advances in component technology for inert gas thrusters are described. The maximum electron emission of a hollow cathode with Ar was increased 60-70% by the use of an enclosed keeper configuration. Operation with Ar, but without emissive oxide, was also obtained. A 30 cm thruster operated with Ar at moderate discharge voltages give double-ion measurements consistent with a double ion correlation developed previously using 15 cm thruster data. An attempt was made to reduce discharge losses by biasing anodes positive of the discharge plasma. The reason this attempt was unsuccessful is not yet clear. The performance of a single-grid ion-optics configuration was evaluated. The ion impingement on the single grid accelerator was found to approach the value expected from the projected blockage when the sheath thickness next to the accelerator was 2-3 times the aperture diameter.

  19. Thermodilution versus inert gas rebreathing for estimation of effective pulmonary blood flow

    DEFF Research Database (Denmark)

    Christensen, P; Clemensen, P; Andersen, P K

    2000-01-01

    To compare measurements of the effective pulmonary blood flow (Qep, i.e., nonshunted fraction of cardiac output, Qt) by the inert gas rebreathing (RB) method and the thermodilution (TD) technique in critically ill patients.......To compare measurements of the effective pulmonary blood flow (Qep, i.e., nonshunted fraction of cardiac output, Qt) by the inert gas rebreathing (RB) method and the thermodilution (TD) technique in critically ill patients....

  20. Fabrication of high temperature superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam; Dorris, Stephen E.; Ma, Beihai; Li, Meiya

    2003-06-17

    A method of forming a biaxially aligned superconductor on a non-biaxially aligned substrate substantially chemically inert to the biaxially aligned superconductor comprising is disclosed. A non-biaxially aligned substrate chemically inert to the superconductor is provided and a biaxially aligned superconductor material is deposited directly on the non-biaxially aligned substrate. A method forming a plume of superconductor material and contacting the plume and the non-biaxially aligned substrate at an angle greater than 0.degree. and less than 90.degree. to deposit a biaxially aligned superconductor on the non-biaxially aligned substrate is also disclosed. Various superconductors and substrates are illustrated.

  1. Inert atmosphere system for plutonium processing gloveboxes

    International Nuclear Information System (INIS)

    Bogard, C.F.; Calkins, K.W.; Rogers, R.F.

    1975-01-01

    Recent efforts to reduce fire hazards in plutonium processing operations are described. In such operations, the major environmental controls are developed through various kinds of glovebox systems. In evaluating the air-atmosphere glovebox systems, formerly in use at Rocky Flats and many other plants, a decision was made to convert to a recirculating ''inert'' atmosphere. The inert atmosphere consists of nitrogen, supplied from an on-site generating plant, diluting oxygen content to one to 5 percent by volume. Problems encountered during the change over included: determination of all factors influencing air leakage into the system, and reducing leakage to the practical minimum; meeting all fire and safety standards on the filter plenum and exhaust systems; provision for converting portions of the system to an air atmosphere to conduct maintenance work; inclusion of oxygen analyzers throughout the system to check gas quality and monitor for leaks; and the use of automatic controls to protect against a variety of potential malfunctions. The current objectives to reduce fire hazards have been met and additional safeguards were added. The systems are operating satisfactorily. (U.S.)

  2. Influence of composition and substrate bias on structure and inert-gas content of sputter-deposited Ni-La alloys

    International Nuclear Information System (INIS)

    Knoll, R.W.; McClanahan, E.D.

    1982-09-01

    X-ray diffraction patterns show that the disappearance of crystallinity in the deposit occurs gradually as the La content increases. At the same time, the deposit becomes saturated with Kr. Because there is no evidence of crystalline La metal or Ni-La intermetallic phase in the diffraction data, it may be concluded that each La atom creates a highly disordered (amorphous) region in the lattice, and that this region contains interstitial voids large enough to capture inert gas atoms. Saturation of the gas content with respect to La/Ni ratio might commence when these disordered regions begin to impinge upon one another. Finally, if inert gas atoms occupy interstitial voids within the deposit, then determination of the gas trapping characteristics of the material, using inert gas ions of different sizes, may be a means of studying the structure of glassy vapor-deposited materials. For example, the size distribution of the interstitial voids might be determined in this manner

  3. Chemical vapour deposition of carbon nanotubes

    CSIR Research Space (South Africa)

    Arendse, CJ

    2006-02-01

    Full Text Available , effective, more versatile and easily scalable to large substrate sizes. In this paper, we present a design of the hot-wire CVD system constructed at the CSIR for the deposition of CNTs. Additionally, we will report on the structure of CNTs deposited... exhibit exceptional chemical and physical properties related to toughness, chemical inertness, magnetism, and electrical and thermal conductivity. A variety of preparation methods to synthesise CNTs are known, e.g. carbon-arc discharge, laser ablation...

  4. Metal ferrite oxygen carriers for chemical looping combustion of solid fuels

    Science.gov (United States)

    Siriwardane, Ranjani V.; Fan, Yueying

    2017-01-31

    The disclosure provides a metal ferrite oxygen carrier for the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The metal ferrite oxygen carrier comprises MFe.sub.xO.sub.y on an inert support, where MFe.sub.xO.sub.y is a chemical composition and M is one of Mg, Ca, Sr, Ba, Co, Mn, and combinations thereof. For example, MFe.sub.xO.sub.y may be one of MgFe.sub.2O.sub.4, CaFe.sub.2O.sub.4, SrFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, CoFe.sub.2O.sub.4, MnFeO.sub.3, and combinations thereof. The MFe.sub.xO.sub.y is supported on an inert support. The inert support disperses the MFe.sub.xO.sub.y oxides to avoid agglomeration and improve performance stability. In an embodiment, the inert support comprises from about 5 wt. % to about 60 wt. % of the metal ferrite oxygen carrier and the MFe.sub.xO.sub.y comprises at least 30 wt. % of the metal ferrite oxygen carrier. The metal ferrite oxygen carriers disclosed display improved reduction rates over Fe.sub.2O.sub.3, and improved oxidation rates over CuO.

  5. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

    Science.gov (United States)

    Ray, Siba P.; Liu, Xinghua

    2000-01-01

    An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

  6. Fabrication of inert matrices for heterogeneous transmutation. EFTTRA-T2 (RAS 2) irradiation programme

    International Nuclear Information System (INIS)

    Boshoven, J.G.; Hein, H.; Konings, R.J.M.

    1996-07-01

    This report describes the fabrication of targets containing inert matrices for the heterogeneous transmutation of plutonium and minor actinides. These targets will be irradiated in the EFTTRA-T2 (RAS-2) irradiation programme. The selection, preparation and characterization of the inert matrices and fabrication and loading of the irradiation capsules are discussed. (orig.)

  7. Mixed PWR core loadings with inert matrix Pu-fuel assemblies

    International Nuclear Information System (INIS)

    Stanculescu, A.; Kasemeyer, U.; Paratte, J.-M.; Chawla, R.

    1999-01-01

    The most efficient way to enhance plutonium consumption in light water reactors is to eliminate the production of plutonium all together. This requirement leads to fuel concepts in which the uranium is replaced by an inert matrix. At PSI, studies have focused on employing ZrO 2 as inert matrix. Adding a burnable poison to such a fuel proves to be necessary. As a result of scoping studies, Er 2 O 3 was identified as the most suitable burnable poison material. The results of whole-core three-dimensional neutronics analyses indicated, for a present-day 1000 MW e pressurised water reactor, the feasibility of an asymptotic equilibrium four-batch cycle fuelled solely with the proposed PuO 2 -Er 2 O 3 -ZrO 2 inert matrix fuel (IMF). The present paper presents the results of more recent investigations related to 'real-life' situations, which call for transition configurations in which mixed IMF and UO 2 assembly loadings must be considered. To determine the influence of the introduction of IMF assemblies on the characteristics of a UO 2 -fuelled core, three-dimensional full-core calculations have been performed for a present-day 1000 MW e PWR containing up to 12 optimised IMF assemblies. (author)

  8. A steam inerting system for hydrogen disposal for the Vandenberg Shuttle

    Science.gov (United States)

    Belknap, Stuart B.

    1988-01-01

    A two-year feasibility and test program to solve the problem of unburned confined hydrogen at the Vandenberg Space Launch Complex Six (SLC-6) during Space Shuttle Main Engine (SSME) firings is discussed. A novel steam inerting design was selected for development. Available sound suppression water is superheated to flash to steam at the duct entrance. Testing, analysis, and design during 1987 showed that the steam inerting system (SIS) solves the problem and meets other flight-critical system requirements. The SIS design is complete and available for installation at SLC-6 to support shuttle or derivative vehicles.

  9. Neutronics performances study of silicon carbide as an inert matrix to achieve very high burn-up for light water reactor fuels

    International Nuclear Information System (INIS)

    Chabert, C.; Coulon-Picard, E.; Pelletier, M.

    2007-01-01

    In order to extend the actual limits of light water reactors, the Cea has put emphasis on the exploration of major fuel innovations that would allow us to increase the competitiveness, the safety and flexibility, while keeping the standard PWR environment. Different fuel concepts have been chosen and are actually studied to evaluate their advantages and drawbacks. The objectives of these new fuels are to increase the safety performances and to achieve a very high burn-up. One concept is a CERCER fuel with silicon carbide (SiC) as an inert matrix devoted to reduce the fuel temperature at nominal conditions. Besides the investigation of the neutronic performance, analyses on the thermomechanical performances, the fuel fabrication, the fuel reprocessing and economic aspects have been performed. This paper presents particularly neutronic results obtained for the CERCER fuel. The results show that a very high burn-up, a high safety performance and a better competitiveness cannot be achieved with this fuel concept. (authors)

  10. Status of the inert matrix fuel program at PSI

    International Nuclear Information System (INIS)

    Ledergerber, G.; Degueldre, C.; Kasemeyer, U.; Stanculescu, A.; Paratte, J.M.; Chawla, R.

    1997-01-01

    Incineration of plutonium by a once-through cycle in LWRs utilising an inert matrix based fuel may prove to be an attractive way of making use of the energy of fissile plutonium and reducing both the hazard potential and the volumes of the waste. Yttria stabilised zirconia forms a solid solution with oxides of rare earth elements (e.g. erbium, cerium) and some actinides. The small absorption cross section, the excellent stability under irradiation, and the insolubility in acids and water recommends this material as an inert matrix. Neutronics calculations with erbium as burnable poison show that these compositions would be optimal from the reactivity point of view. A fuel element with an improved reactivity behaviour over its life cycle has been designed for possible introduction into a heterogeneous LWR core. (author). 16 refs., 1 tab., 10 figs

  11. Ultrasmooth, Polydopamine Modified Surfaces for Block Copolymer Nanopatterning on Inert and Flexible Substrates

    Science.gov (United States)

    Katsumata, Reika; Cho, Joon Hee; Zhou, Sunshine; Kim, Chae Bin; Dulaney, Austin; Janes, Dustin; Ellison, Christopher

    Nature has engineered universal, catechol-containing adhesives that can be synthetically mimicked in the form of polydopamine (PDA). We exploited PDA to enable block copolymer (BCP) nanopatterning on a variety of soft material surfaces in a way that can potentially be applied to flexible electrical devices. Applying BCP nanopatterning to soft substrates is challenging because soft substrates are often chemically inert and possess incompatible low surface energies. In this study, we exploited PDA to enable the formation of BCP nanopatterns on a variety of surfaces such as Teflon, poly(ethylene terephthalate) (PET), and Kapton. While previous studies produced a PDA coating layer too rough for BCP nanopatterning, we succeeded in fabricating conformal and ultra-smooth surfaces of PDA by engineering the PDA coating process and post-sonication procedure. This chemically functionalized, biomimetic thin film (3 nm thick) served as a reactive platform for subsequently grafting a surface treatment to perpendicularly orient a lamellae-forming BCP layer. Furthermore, we demonstrated that a perfectly nanopatterned PDA-PET substrate can be bent without distorting or damaging the nanopattern in conditions that far exceeds typical bending curvatures in roll-to-roll manufacturing.

  12. For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

    Science.gov (United States)

    Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.

    2002-01-01

    A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

  13. Spectroscopic Diagnostics of Barrier Discharge Plasmas in Mixtures of Zinc Diiodide with Inert Gases

    International Nuclear Information System (INIS)

    Guivan, N.N.; Malinin, A.N.

    2005-01-01

    The spectral characteristics of the emission of gas discharge atmospheric pressure plasmas in mixtures of zinc diiodide vapor with inert gases (He, Ne, Ar, Kr, and Xe) are investigated. The formation of a gas discharge plasma and the excitation of the components of a working mixture were performed in a high-frequency (with a repetition frequency of sinusoidal voltage pulses of 100 kHz) barrier discharge. The gas discharge emission was analyzed in the spectral range 200-900 nm with a resolution of 0.05 nm. Emission bands of ZnI(B-X) exciplex molecules and I* 2 excimer molecules, lines of inert gases, and emission bands of XeI* exciplex molecules (in Xe-containing mixtures) were revealed. It is ascertained that the strongest emission of ZnI* molecules is observed in ZnI 2 /He(Ne) mixtures. The regularities in the spectral characteristics of the gas discharge plasma emission are considered

  14. Fabrication of BN Nanosheet Reinforced ZrO{sub 2} Composite Pellets for Inert Matrix Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Shukeir, Malik; Umer, Malik; Lee, Bin; Ryu, Ho Jin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    Plutonium also can be resulted from the dismantlement of nuclear weapons. This will result in the increase of the stockpile of plutonium. For that purpose many organizations are focusing their R-D work on the concept of Inert Matrix Fuel IMF, where a U-free matrix is used to eliminate the U-Pu conversion. R-D work was standardized around Zirconiabased IMF as a result of many screening and ranking studies performed on various candidates. Regardless of its outstanding radiation resistance, chemical stability and its high melting point, it has a very low thermal conductivity, which could be detrimental for the fuel matrix especially in case of accidents. A reinforcement phase could be used for the enhancement of the thermomechanical properties. Among many possible reinforcements, 2D structured nanosheets have emerged as an excellent candidate to enhance the thermal properties and mechanical properties simultaneously. In this approach Boron Nitride Nanosheets BNNS are used for that purpose. BNNS have a very low density, very high thermal conductivity, very high mechanical properties and high neutron absorption cross-section for Boron which is used frequently as a burnable poison. They have properties similar to graphene but they exhibit superior thermal stability in the oxide structure. Despite all the studies on other reinforcements, BNNS reinforced ZrO{sub 2} has not yet been reported. In this study, pure ZrO{sub 2} and partially stabilized Zirconia PSZ (using Yttria) ceramics are mixed with different volume fractions of BNNS.

  15. Theoretical and Experimental Studies of a Switched Inertance Hydraulic System in a Four-Port High-Speed Switching Valve Configuration

    Directory of Open Access Journals (Sweden)

    Min Pan

    2017-06-01

    Full Text Available The switched inertance hydraulic system (SIHS is a novel high-bandwidth and energy-efficient digital device which can adjust or control flow and pressure by a means that does not rely on throttling the flow and dissipation of power. An SIHS can provide an efficient step-up or step-down of pressure or flow rate by using a digital control signal. In this article, analytical models of an SIHS in a four-port high-speed switching valve configuration are proposed, and the system dynamics and performance are investigated theoretically and experimentally. The flow responses, system characteristics, and power consumption can be predicted effectively and accurately by using the proposed models, which were validated by comparing with experiments and with numerical simulation. The four-port configuration is compared with the three-port configuration, and it is concluded that the former one is less efficient for valves of the same size, but provides a bi-direction control capability. As bi-direction control is a common requirement, this constitutes an important contribution to the development of efficient digital hydraulics.

  16. Viability of inert matrix fuel in reducing plutonium amounts in reactors

    International Nuclear Information System (INIS)

    2006-08-01

    Reactors worldwide have produced more than 2000 tonnes of plutonium, contained in spent fuel or as separated forms through reprocessing. Disposition of fissile materials has become a primary concern of nuclear non-proliferation efforts. There is a significant interest in IAEA Member States to develop proliferation resistant nuclear fuel cycles for incineration of plutonium such as inert matrix fuels (IMFs). The present report summarises R and D work on inert matrix fuel for plutonium and (to a lesser extent) minor actinide stock-pile reduction, and discusses the possible strategies to include inert matrix fuel approaches to the nuclear fuel cycle. The publication reviews the status of potential IMF candidates and describes several identified candidate materials for both fast and thermal reactors: MgO, ZrO2, SiC, Zr alloy, SiAl, ZrN; some of these have undergone test irradiations and post-irradiation examination. Also discussed are modelling of IMF fuel performance and safety analysis. System studies have identified strategies for both implementation of IMF fuel as homogeneous or heterogeneous phases, as assemblies or core loadings and in existing reactors in the shorter term, as well as in new reactors in the longer term

  17. Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers

    Science.gov (United States)

    Wellman, Tristan; Shapiro, Allen M.; Hill, Mary C.

    2009-01-01

    While it is widely recognized that highly permeable 'large-scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive 'small-scale' fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of chemical migration through fracture-controlled aquifers is used to advance this conceptual understanding. The influence of fracture structure is evaluated by quantifying the effects to transport caused by a systematic removal of fractures from three-dimensional discrete fracture models whose attributes are derived from geologic and hydrologic conditions at multiple field sites. Results indicate that the effects to transport caused by network simplification are sensitive to the fracture network characteristics, degree of network simplification, and plume travel distance, but primarily in an indirect sense since correlation to individual attributes is limited. Transport processes can be 'enhanced' or 'restricted' from network simplification meaning that the elimination of fractures may increase or decrease mass migration, mean travel time, dispersion, and tailing of the concentration plume. The results demonstrate why, for instance, chemical migration may not follow the classic advection-dispersion equation where dispersion approximates the effect of the ignored geologic structure as a strictly additive process to the mean flow. The analyses further reveal that the prediction error caused by fracture network simplification is reduced by at least 50% using the median estimate from an ensemble of simplified fracture network models, and that the error from network simplification is at least 70% less than the stochastic variability from multiple realizations. Copyright 2009 by the American Geophysical Union.

  18. Relationships among ventilation-perfusion distribution, multiple inert gas methodology and metabolic blood-gas tensions.

    Science.gov (United States)

    Lee, A S; Patterson, R W; Kaufman, R D

    1987-12-01

    The retention equations upon which the Multiple Inert Gas Method is based are derived from basic principles using elementary algebra. It is shown that widely disparate distributions produce indistinguishable sets of retentions. The limits of resolution of perfused compartments in the VA/Q distribution obtainable by the use of the multiple inert gas method are explored mathematically, and determined to be at most shunt and two alveolar compartments ("tripartite" distribution). Every continuous distribution studied produced retentions indistinguishable from those of its unique "matching" tripartite distribution. When a distribution is minimally specified, it is unique. Any additional specification (increased resolution--more compartments) of the distribution results in the existence of an infinitude of possible distributions characterized by indistinguishable sets of retention values. No further increase in resolution results from the use of more tracers. When sets of retention values were extracted from published multiple inert gas method continuous distributions, and compared with the published "measured" retention sets, substantial differences were found. This illustrates the potential errors incurred in the practical, in vivo application of the multiple inert gas method. In preliminary studies, the tripartite distribution could be determined with at least comparable accuracy by blood-gas (oxygen, carbon dioxide) measurements.

  19. Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chunrui [Univ. of Texas, San Antonio, TX (United States); Enriquez, Erik [Univ. of Texas, San Antonio, TX (United States); Wang, Haibing [Univ. of Texas, San Antonio, TX (United States); Xu, Xing [Univ. of Texas, San Antonio, TX (United States); Bao, Shangyong [Univ. of Texas, San Antonio, TX (United States); Collins, Gregory [Univ. of Texas, San Antonio, TX (United States)

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo2O5+d (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  20. Dissolved helium, inert gases, radium and radon in groundwaters from the Altnabreac research site

    International Nuclear Information System (INIS)

    Andrews, J.N.; Kay, R.L.F.

    1985-01-01

    A groundwater geochemical study has been carried out at Altnabreac, Cenithness, Scotland, to investigate the feasibility of disposal of high-level radioactive wastes in crystalline rock. A groundwater flow model was constructed for sampling a section at depths up to 300 m. Measurements of inert gases dissolved in groundwaters are used, with parallel measurements of 14 C, tritium, oxygen and hydrogen isotopes to infer groundwater ages and residence times. (UK)

  1. Mechanical behaviour and diffusion of gas during neutron irradiation of actinides in ceramic inert matrices

    NARCIS (Netherlands)

    Neeft, E.A.C.

    2004-01-01

    Fission of actinides from nuclear waste in inert matrices (materials without uranium) can reduce the period in time that nuclear waste is more radiotoxic than uranium ore that is the rock from which ordinary reactor fuel is made. A pioneering study is performed with the inert matrices: MgO, MgAl2O4,

  2. Development and characterization of ceramic composites alumina-titania based reinforced with lanthanum oxide for fabrication of inert coatings for metallic tanks of the oil industry; Desenvolvimento e caracterizacao de compositos ceramicos baseados em alumina-titania reforcados com oxido de lantanio para fabricacao de revestimentos inertes em tanques metalicos da industria petrolifera

    Energy Technology Data Exchange (ETDEWEB)

    Bandeira, J.M.; Yadava, Y.P.; Silva, N.D.G.; Ferreira, R.A.S., E-mail: julianamb91@gmail.com, E-mail: yadava@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Departamento de Engenharia Mecanica

    2016-07-01

    Crude petroleum is highly corrosive causing superficial degradation in metallic tanks used for storage and transportation of this material, which causes a serious problem in the oil industry. An alternative to solve this problem is to use some kind of coating that is inert to this kind of corrosion. Alumina and titania are interesting materials for several engineering applications because, when compared with other ceramic materials, they present superior mechanical properties, e.g. high mechanical strength, good chemical stability and high fracture toughness combined with good wear resistance and a coefficient of thermal expansion close to the iron's, which makes them fit to use in ceramic hardening process and coating. In this paper, alumina-titania ceramic composites with 5%, 10%, 15% and 20% of titania (TiO2) and reinforced with 2% of lanthanum oxide of were produced by thermo-mechanical processing and sintering techniques at 1350 deg C. In these composites, microstructure and mechanical properties were analyzed using X-ray spectroscopy, optical microscopy, scanning electron microscopy and Vickers hardness in order to evaluate their applicability. X-ray spectroscopy showed the formation of composite without the presence of other phases. Optical microscopy and scanning electron microscopy showed a homogeneous microstructure in terms of particle size and distribution. Vickers hardness test showed a gradual decrease in hardness with the addition of titania. The composite with 5% of titania and 2% of lanthanum oxide is the best choice for structural applications. The composites were submerged in crude petroleum for 30 days to study their stability in such environment. Through the analysis of X-ray spectroscopy, optical microscopy and Vickers hardness before and after the submersion in crude petroleum, it was not observed structural or microstructural degradation nether alterations in mechanical properties. This way, it was concluded that these composites have

  3. Effect of composition on thermal conductivity of MgO–Nd2Zr2O7 composites for inert matrix materials

    International Nuclear Information System (INIS)

    Nelson, A.T.; Giachino, M.M.; Nino, J.C.; McClellan, K.J.

    2014-01-01

    Inert matrix fuels based on magnesium oxide (MgO) as the inert phase have been of historic interest due to its high thermal conductivity. Minor actinide-bearing phases possessing an A 2 B 2 O 7 pyrochlore structure are also believed to contain a range of favorable attributes, suggesting a possible pairing with MgO to yield a high performance inert matrix fuel. The thermal diffusivity, heat capacity, and thermal expansion of MgO–Nd 2 Zr 2 O 7 composites were measured from room temperature to 1273 K, where the MgO phase content was varied from 40 to 70 volume percent. The thermal conductivity of each composition was calculated using these results and then compared to widely employed methods to approximate the thermal conductivity of composite materials based upon the properties of the constituent phases. Results suggest that use of either a rule of mixtures or geometric mean approximation for the thermal conductivity of composite systems such as this one would be subject to significant uncertainties when the constituent properties widely differ. A sigmoidal average of the upper and lower Hashin–Shtrikman bounds was found to be in good agreement with the thermal conductivity of the composites as determined experimentally

  4. Effects of radiative heat transfer on the turbulence structure in inert and reacting mixing layers

    International Nuclear Information System (INIS)

    Ghosh, Somnath; Friedrich, Rainer

    2015-01-01

    We use large-eddy simulation to study the interaction between turbulence and radiative heat transfer in low-speed inert and reacting plane temporal mixing layers. An explicit filtering scheme based on approximate deconvolution is applied to treat the closure problem arising from quadratic nonlinearities of the filtered transport equations. In the reacting case, the working fluid is a mixture of ideal gases where the low-speed stream consists of hydrogen and nitrogen and the high-speed stream consists of oxygen and nitrogen. Both streams are premixed in a way that the free-stream densities are the same and the stoichiometric mixture fraction is 0.3. The filtered heat release term is modelled using equilibrium chemistry. In the inert case, the low-speed stream consists of nitrogen at a temperature of 1000 K and the highspeed stream is pure water vapour of 2000 K, when radiation is turned off. Simulations assuming the gas mixtures as gray gases with artificially increased Planck mean absorption coefficients are performed in which the large-eddy simulation code and the radiation code PRISSMA are fully coupled. In both cases, radiative heat transfer is found to clearly affect fluctuations of thermodynamic variables, Reynolds stresses, and Reynolds stress budget terms like pressure-strain correlations. Source terms in the transport equation for the variance of temperature are used to explain the decrease of this variance in the reacting case and its increase in the inert case

  5. Post-inertization of large dry containments in case of beyond-design base events in PWR plants

    International Nuclear Information System (INIS)

    Tiltmann, M.; Risse, D.; Pana, P.; Huettermann, B.; Rohde, J.

    1993-12-01

    The objective is to present a summary of basic thoughts and concepts as described in various publications. The report points out the obvious advantages and disadvantages of individual strategies as wel as the requirements derived from the knowledge of possible accident sequences for such a concept. Scoping calculations on the injection of inert-gas into the containment during the progress of accidents revealed additional indications as regards e.g. the required amount of inert-gas, the injection rate, and the resulting pressure behaviour in the containment. Thereby an assessment of the effectiveness as well as of the feasibility of such measures has become possible. From the large number of different initial conclusions, two major ones are singled out and presented: 1) In principle, the technical realisation of post-inerting is possible. Thus a deflagration of hydrogen in the containment can be prevented; 2) Post-inerting cannot be realised independent of the accident progress. Specific criteria for carrying out such measures will require extensive examinations. (orig./HP) [de

  6. An investigation of the microstructures and properties of metal inert ...

    Indian Academy of Sciences (India)

    Friction stir welding; metal inert gas welding; aluminum alloy 5083; ... (2008) have studied fatigue crack propagation behaviour of friction ..... Kumar K, Kailas SV 2008 The role of friction stir welding tool on material flow and weld formation,.

  7. Plutonium fuel lattice neutron behavior in inert matrix

    International Nuclear Information System (INIS)

    Hernandez L, H.; Lucatero, M. A.

    2010-10-01

    In several countries is had been researching the possibility of using plutonium, as weapon degree as reactor degree, as fuel material in commercial reactors to generate electricity. In special a great development has been in Pressure Water Reactors. However, in Mexico the reactors are Boiling Water Reactors type, reason for which the necessity to considers feasibility to use this fuel type in the reactors of nuclear power plant of Laguna Verde. For this propose a comparison of fuel lattice that compose a fuel assembly is made. The fuel assembly will propose to be used whit in the reactor present different inert matrix, as well as burnable poison. The material that compose the inert matrices used are cerium and zirconia (CeO 2 and ZrO 2 ) and as burnable poisons have gadolinium and erbium (Gd 2 O 4 and ErO 2 ). As far as the hydraulic design used is a cell 10 X 10 with two water channels. The lattice calculations are made with the Helios code a library with 35 energy groups, having determined the pin power factors, the infinite multiplication factor and the neutron flux profiles. (Author)

  8. effects of metal inert gas welding parameters on some mechanical ...

    African Journals Online (AJOL)

    EFFECTS OF METAL INERT GAS WELDING PARAMETERS ON SOME MECHANICAL PROPERTIES OF AUSTENITIC STAINLESS STEEL IN ACIDIC ... Design Expert Software, Scanning Electron Microscopy (SEM), Rockwell Hardness Test, Monsanto Tensometer and Izod Impact Test were used to determine the ...

  9. Runaway chemical reaction exposes community to highly toxic chemicals

    International Nuclear Information System (INIS)

    Kaszniak, Mark; Vorderbrueggen, John

    2008-01-01

    The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a comprehensive investigation of a runaway chemical reaction at MFG Chemical (MFG) in Dalton, Georgia on April 12, 2004 that resulted in the uncontrolled release of a large quantity of highly toxic and flammable allyl alcohol and allyl chloride into the community. Five people were hospitalized and 154 people required decontamination and treatment for exposure to the chemicals. This included police officers attempting to evacuate the community and ambulance personnel who responded to 911 calls from residents exposed to the chemicals. This paper presents the findings of the CSB report (U.S. Chemical Safety and Hazard Investigation Board (CSB), Investigation Report: Toxic Chemical Vapor Cloud Release, Report No. 2004-09-I-GA, Washington DC, April 2006) including a discussion on tolling practices; scale-up of batch reaction processes; Process Safety Management (PSM) and Risk Management Plan (RMP) implementation; emergency planning by the company, county and the city; and emergency response and mitigation actions taken during the incident. The reactive chemical testing and atmospheric dispersion modeling conducted by CSB after the incident and recommendations adopted by the Board are also discussed

  10. Distribution of inert gases in fines from the Cayley-Descartes region

    Science.gov (United States)

    Walton, J. R.; Lakatos, S.; Heymann, D.

    1973-01-01

    The inert gases in 14 different fines and in one sample of 2 to 4 mm fines from Apollo 16 were measured by mass spectroscopy with respect to trapped solar wind gases, cosmogenic gases, and 'parentless' Ar-40. Such studies are helpful for the understanding of regolith evolution, of transport of regolith fines, and of the lunar atmosphere. The Apollo 16 soils are unique because they represent, after Luna 20, the second and much more extensive record from the lunar highlands. The landing site presents the problem of materials from the Cayley Formation vs those from the Descartes Formation. There are two large, relatively fresh craters in the area, North Ray and South Ray, whose ejecta patterns may be recognized in the inert-gas record.

  11. Physicochemical effects on uncontaminated kaolinite due to electrokinetic treatment using inert electrodes.

    Science.gov (United States)

    Liaki, Christina; Rogers, Christopher D F; Boardman, David I

    2008-07-01

    To determine the consequences of applying electrokinetics to clay soils, in terms of mechanisms acting and resulting effects on the clay, tests were conducted in which an electrical gradient was applied across controlled specimens of English China Clay (ECC) using 'inert' electrodes and a 'Reverse Osmosis' water feed to the electrodes (i.e., to mimic electrokinetic stabilisation without the stabiliser added or electrokinetic remediation without the contaminant being present). The specimens in which electromigration was induced over time periods of 3, 7, 14 and 28 days were subsequently tested for Atterberg Limits, undrained shear strength using a hand shear vane, water content, pH, conductivity and zeta potential. Water flowed through the system from anode to cathode and directly affected the undrained shear strength of the clay. Acid and alkali fronts were created around the anode and cathode, respectively, causing changes in the pH, conductivity and zeta potential of the soil. Variations in zeta potential were linked to flocculation and dispersion of the soil particles, thus raising or depressing the Liquid Limit and Plastic Limit, and influencing the undrained shear strength. Initial weakening around the anode and cathode was replaced by a regain of strength at the anode once acidic conditions had been created, while highly alkaline conditions at the cathode induced a marked improvement in strength. A novel means of indicating strength improvement by chemical means, i.e., free from water content effects, is presented to assist in interpretation of the results.

  12. Modelling the interaction of high energy ions with inert matter, living matter, and moving matter

    International Nuclear Information System (INIS)

    Beuve, Michael

    2007-01-01

    In this report for accreditation to supervise research (HDR), the author proposes a synthetic (and however relatively detailed) overview of his research works in the fields of physics and radiology. The first part addresses works in the field of interaction between ions and inert matter (Monte Carlo simulation of emission induced by ion-solid interaction, simulation by molecular dynamics of pulverization). The second part addresses the interaction between ions and living matter: research strategy, principle of the Local Effect Model (LEM) and influence of its main parameters, LEM experimental assessment, LEM theoretical analysis, role of the cell oxidizing and anti-oxidizing system. The next part addresses the interaction of ions with moving matter: research strategy, lung mechanics modelling and clinical assessments, chest wall mechanics, transformation of movements simulated in 4D scanner imagery

  13. Minimum ignition energy of nano and micro Ti powder in the presence of inert nano TiO₂ powder.

    Science.gov (United States)

    Chunmiao, Yuan; Amyotte, Paul R; Hossain, Md Nur; Li, Chang

    2014-06-15

    The inerting effect of nano-sized TiO2 powder on ignition sensitivity of nano and micro Ti powders was investigated with a Mike 3 apparatus. "A little is not good enough" is also suitable for micro Ti powders mixed with nano-sized solid inertants. MIE of the mixtures did not significantly increase until the TiO2 percentage exceeded 50%. Nano-sized TiO2 powders were ineffective as an inertant when mixed with nano Ti powders, especially at higher dust loadings. Even with 90% nano TiO2 powder, mixtures still showed high ignition sensitivity because the statistic energy was as low as 2.1 mJ. Layer fires induced by ignited but unburned metal particles may occur for micro Ti powders mixed with nano TiO2 powders following a low level dust explosion. Such layer fires could lead to a violent dust explosion after a second dispersion. Thus, additional attention is needed to prevent metallic layer fires even where electric spark potential is low. In the case of nano Ti powder, no layer fires were observed because of less flammable material involved in the mixtures investigated, and faster flame propagation in nanoparticle clouds. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Fuel hydrogen retention of tungsten and the reduction by inert gas glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Hino, T., E-mail: tomhino@qe.eng.hokudai.ac.jp [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Yamauchi, Y.; Kimura, Y. [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292 (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, Suita-shi 565-0872 (Japan)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The performances of inert gas glow discharges for reduction of fuel hydrogen retention in tungsten were systematically investigated. Black-Right-Pointing-Pointer For the tungsten with rough surface structure, the reduction of fuel hydrogen retention by inert gas discharges is quite small. Black-Right-Pointing-Pointer The deuterium glow discharge is quite useful to reduce the tritium retention in plasma facing walls in fusion reactor. Black-Right-Pointing-Pointer The wall baking with temperature higher than 700-800 K is also useful to reduce the tritium retention in plasma facing walls. - Abstract: Polycrystalline tungsten was exposed to deuterium glow discharge followed by He, Ne or Ar glow discharge. The amount of retained deuterium in the tungsten was measured using residual gas analysis. The amount of desorbed deuterium during the inert gas glow discharge was also measured. The amount of retained deuterium was 2-3 times larger compared with a case of stainless steel. The ratios of desorbed amount of deuterium by He, Ne and Ar glow discharges were 4.6, 3.1 and 2.9%, respectively. These values were one order of magnitude smaller compared with the case of stainless steel. The inert gas glow discharge is not suitable to reduce the fuel hydrogen retention for tungsten walls. However, the wall baking with a temperature higher than 700 K is suitable to reduce the fuel hydrogen retention. It is also shown that the use of deuterium glow discharge is effective to reduce the in-vessel tritium inventory in fusion reactors through the hydrogen isotope exchange.

  15. Technical basis for storage of Zircaloy-clad spent fuel in inert gases

    International Nuclear Information System (INIS)

    Johnson, A.B. Jr.; Gilbert, E.R.

    1983-09-01

    The technical bases to establish safe conditions for dry storage of Zircaloy-clad fuel are summarized. Dry storage of fuel with zirconium alloy cladding has been licensed in Canada, the Federal Republic of Germany, and Switzerland. Dry storage demonstrations, hot cell tests, and modeling have been conducted using Zircaloy-clad fuel. The demonstrations have included irradiated boiling water reactor, pressurized heavy-water reactor, and pressurized water reactor fuel assemblies. Irradiated fuel has been emplaced in and retrieved from metal casks, dry wells, silos, and a vault. Dry storage tests and demonstrations have involved about 15,000 fuel rods, and about 5600 rods have been monitored during dry storage in inert gases with maximum cladding temperatures ranging from 50 to 570 0 C. Although some tests and demonstrations are still in progress, there is currently no evidence that any rods exposed to inert gases have failed (one PWR rod exposed to an air cover gas failed at about 270 0 C). Based on this favorable experience, it is concluded that there is sufficient information on fuel rod behavior, storage conditions, and potential cladding failure mechanisms to support licensing of dry storage in the US. This licensing position includes a requirement for inert cover gases and a maximum cladding temperature guideline of 380 0 C for Zircaloy-clad fuel. Using an inert cover gas assures that even if fuel with cladding defects were placed in dry storage, or if defects develop during storage, the defects would not propagate. Tests and demonstrations involving Zircaloy-clad rods and assemblies with maximum cladding temperatures above 400 0 C are in progress. When the results from these tests have been evaluated, the viability of higher temperature limits should be examined. Acceptable conditions for storage in air and dry storage of consolidated fuel are issues yet to be resolved

  16. Removal of the Inert Organic Fraction of Municipal Wastewater Using the Integrated Activated Sludge/Trickling Filter System

    Directory of Open Access Journals (Sweden)

    mehraban sadeghi

    2015-01-01

    Full Text Available The discharge of phenol and chlorinated compounds, fatty acids, tannin, lignin, and their by-products into receptive waters poses serious hazards for the aquatic life. In this study, the efficiency of a tow-step process of activated sludge-trickling filter (AS/TF in the removal of inert chemical materials that defy conventional treatment processes was investigated. For this purpose, an integrated activated sludge process (industrial scale was used sequentially with a trickling filter (pilot scale. Inside a tank with an effective volume of 6.87 m3 was installed 5.78 m3 of polypropylene 2HX media with a specific area of 240 m2/m3. The hydraulic loading rate (HLR of the trickling filter during the startup period (90 days was 3.6 m3/h which was raised to 3.6-6 m3/h in the operation period (120 days, with the best effluent quality achieved at HLR=5.4 m3/h. For the purposes of the experiments in this study, four reactors, each 1256 cm3 in volume, were fed the WWTP effluent and concurrently a glucose substrate containing a COD content equal to that fed to the four reactors was fed into two identical reactors; all the reactors were subsequently run for 480 h in aerobic conditions. Nutrients, pH, and DO (as environmental control indicators as well as soluble and total COD were measured twice daily. The effluent values of soluble inert materials (SI, total soluble COD (STO, degradable suspended materials (XSO, degradable COD (CSO, refractory suspended materials (XI, and degradable soluble materials (SSO for AS were calculated as 40, 227, 94, 281, 251, and 187, respectively, while the same parameters for the AS/TF were 20, 227, 104, 311, 241, and 207 mg/l, respectively. The results showed that the activated sludge process when combined with the trickling filter has a twofold capability, compared to when used alone, in removing inert COD. It was also shown that treatment levels in conventional WWTPs can be improved by integrating conventional treatment

  17. Measurements of hydrogen concentration in liquid sodium by using an inert gas carrier method

    International Nuclear Information System (INIS)

    Funada, T.; Nihei, I.; Yuhara, S.; Nakasuji, T.

    1979-01-01

    A technique was developed to measure the hydrogen level in liquid sodium using an inert gas carrier method. Hydrogen was extracted into an inert gas from sodium through a thin nickel membrane in the form of a helically wound tube. The amount of hydrogen in the inert gas was analyzed by gas chromatography. The present method is unique in that it can be used over the wide range of sodium temperatures (150 to 700 0 C) and has no problems associated with vacuum systems. The partial pressure of hydrogen in sodium was determined as a function of cold-trap temperature (T/sub c/). Sieverts' constant (K/sub s/) was determined as a function of sodium temperature (T). From Sieverts' constant, the solubility of hydrogen in sodium is calculated. It was found that other impurities in sodium, such as (O) and (OH), have little effect on the hydrogen pressure in the sodium loop

  18. Bonding pathways of high-pressure chemical transformations

    International Nuclear Information System (INIS)

    Hu Anguang; Zhang Fan

    2013-01-01

    A three-stage bonding pathway towards high-pressure chemical transformations from molecular precursors or intermediate states has been identified by first-principles simulations. With the evolution of principal stress tensor components in the response of chemical bonding to compressive loading, the three stages can be defined as the van der Waals bonding destruction, a bond breaking and forming reaction, and equilibrium of new bonds. The three-stage bonding pathway leads to the establishment of a fundamental principle of chemical bonding under compression. It reveals that during high-pressure chemical transformation, electrons moving away from functional groups follow anti-addition, collision-free paths to form new bonds in counteracting the local stress confinement. In applying this principle, a large number of molecular precursors were identified for high-pressure chemical transformations, resulting in new materials. (fast track communication)

  19. Inert matrix fuel in dispersion type fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Savchenko, A.M. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation)]. E-mail: sav@bochvar.ru; Vatulin, A.V. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Morozov, A.V. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Sirotin, V.L. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Dobrikova, I.V. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Kulakov, G.V. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Ershov, S.A. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Kostomarov, V.P. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation); Stelyuk, Y.I. [A.A. Bochvar All-Russia Research Institute of Inorganic Materials (VNIINM) 123060, P.O. Box 369, Rogova Street, 5A, Moscow (Russian Federation)

    2006-06-30

    The advantages of using inert matrix fuel (IMF) as a dispersion fuel in an aluminium alloy matrix are considered, in particular, low temperatures in the fuel centre, achievable high burn-ups, serviceability in transients and an environmentally friendly process of fuel rod fabrication. Two main versions of IMF are under development at A.A. Bochvar Institute, i.e. heterogeneous or isolated distribution of plutonium. The out-of-pile results on IMF loaded with uranium dioxide as plutonium simulator are presented. Fuel elements with uranium dioxide composition fabricated at A.A. Bochvar Institute are currently under MIR tests (RIAR, Dimitrovgrad). The fuel elements reached a burn-up of 88 MW d kg{sup -1} (equivalent to the burn up of the standard uranium dioxide pelletized fuel) without loss of leak-tightness of the cladding. The feasibility of fabricating IMF of these particular types with plutonium dioxide is considered with a view to in-pile irradiation.

  20. Inert matrix fuel in dispersion type fuel elements

    Science.gov (United States)

    Savchenko, A. M.; Vatulin, A. V.; Morozov, A. V.; Sirotin, V. L.; Dobrikova, I. V.; Kulakov, G. V.; Ershov, S. A.; Kostomarov, V. P.; Stelyuk, Y. I.

    2006-06-01

    The advantages of using inert matrix fuel (IMF) as a dispersion fuel in an aluminium alloy matrix are considered, in particular, low temperatures in the fuel centre, achievable high burn-ups, serviceability in transients and an environmentally friendly process of fuel rod fabrication. Two main versions of IMF are under development at A.A. Bochvar Institute, i.e. heterogeneous or isolated distribution of plutonium. The out-of-pile results on IMF loaded with uranium dioxide as plutonium simulator are presented. Fuel elements with uranium dioxide composition fabricated at A.A. Bochvar Institute are currently under MIR tests (RIAR, Dimitrovgrad). The fuel elements reached a burn-up of 88 MW d kg-1 (equivalent to the burn up of the standard uranium dioxide pelletized fuel) without loss of leak-tightness of the cladding. The feasibility of fabricating IMF of these particular types with plutonium dioxide is considered with a view to in-pile irradiation.

  1. Comparison of three inert markers in measuring apparent nutrient digestibility of juvenile abalone under different culture condition and temperature regimes

    Science.gov (United States)

    Nur, K. U.; Adams, L.; Stone, D.; Savva, N.; Adams, M.

    2018-03-01

    A comparative research using three inert markers, chromic oxide, yttrium and ytterbium to measure the apparent nutrient digestibility of experimental feed in juvenile Hybrid abalone (Haliotis rubra X H. laevigata) and Greenlip abalone (H.laevigata) revealed that apparent digestibility of crude protein (ADCP) measured using yttrium and ytterbium in hybrid abalone were significantly different across the treatments. Protein digestibility measured in experimental tanks was higher than those measured in indoor and outdoor commercial tanks, regardless of inert marker used. Chromic oxide led to overestimated ADCP compared to when measured using yttrium and ytterbium. There were no significant interactions between temperature and inert markers when measuring ADCP and apparent digestibility of gross energy (ADGE). However, there was a significant difference of ADCP amongst inert markers when measured in greenlip abalone cultured at two temperatures. While measurements of ADge calculated using three inert markers shared the same value.

  2. Inertization of galvanic sludges by its incorporation in ceramic products

    Directory of Open Access Journals (Sweden)

    Ferreira, J. M. F.

    1999-04-01

    Full Text Available Sludges produced by the physico-chemical treatments of waste waters generated by electroplating plants were physically and chemically characterised and incorporated in ceramic pastes. The influence of the amount of sludges added to a typical brick composition on the various processing steps and on the green and fired properties was studied. The environmental risks of the incorporation of these sludges rich in heavy metals such as Cr, Pb, Zn, Cu, Ni, etc. were evaluated by performing leaching tests on the fired products. The results showed that sludge contents up to 15 % could be incorporated without affecting significantly the physical characteristics of the ceramic products. Furthermore, a successful inertization of the pollutants was achieved.

    Se han caracterizado desde el punto de vista químico y físico lodos procedentes de las aguas residuales de procesos de galvanizado. Posteriormente se han incorporado a pastas cerámicas, convencionales de la industria ladrillera, estudiándose la influencia de las cantidades añadidas sobre las propiedades de los materiales tanto en verde como en el producto final y durante las distintas etapas de fabricación. Se evaluaron los riesgos medioambientales derivados de la incorporación de los metales pesados, tales como Cr, Pb, Zn, Cu, Ni etc, presentes en los lodos, mediante la realización de ensayos de lixiviado. Los resultados indican que puede incorporarse hasta un 15% en peso de dichos lodos, sin que se produzcan cambios significativos en las propiedades físicas de los materiales cerámicos obtenidos. Se ha obtenido, asimismo, un procedimiento viable de inertización de los agentes contaminantes.

  3. Inert Layered Silicate Improves the Electrochemical Responses of a Metal Complex Polymer.

    Science.gov (United States)

    Eguchi, Miharu; Momotake, Masako; Inoue, Fumie; Oshima, Takayoshi; Maeda, Kazuhiko; Higuchi, Masayoshi

    2017-10-11

    A chemically inert, insulating layered silicate (saponite; SP) and an iron(II)-based metallo-supramolecular complex polymer (polyFe) were combined via electrostatic attraction to improve the electrochromic properties of polyFe. Structural characterization indicated that polyFe was intercalated into the SP nanosheets. Interestingly, the redox potential of polyFe was lowered by combining it with SP, and the current was measurable despite the insulating nature of SP. X-ray photoelectron spectroscopy showed that the decrease in the redox potential observed in the SP-polyFe hybrid was caused by the electrostatic neutralization of the Fe cation in polyFe by the negative charge on SP. Electrochemical analyses indicated that electron transfer occurred through electron hopping across the SP-polyFe hybrid. Control experiments using a metal complex composed of Fe and two 2,2':6',2''-terpyridine ligands (terpyFe) showed that SP contributes to the effective electron hopping. This modulation of the electrochemical properties by the layered silicates could be applied to other electrochemical systems, including hybrids of the redox-active ionic species and ion-exchangeable adsorbents.

  4. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  5. Post-irradiation examinations of inert matrix nitride fuel irradiated in JMTR (01F-51A capsule)

    International Nuclear Information System (INIS)

    Iwai, Takashi; Nakajima, Kunihisa; Kikuchi, Hironobu; Honda, Junichi; Hatakeyama, Yuichi; Ono, Katsuto; Matsui, Hiroki; Arai, Yasuo

    2007-03-01

    A plutonium nitride fuel pin containing inert matrix such as ZrN and TiN was encapsulated in 01F-51A and irradiated in JMTR. Minor actinides are surrogated by plutonium. Average linear powers and burnups were 408W/cm, 30000MWd/t(Zr+Pu) [132000MWd/t-Pu] for (Zr,Pu)N and 355W/cm, 38000MWd/t(Ti+Pu) [153000MWd/t-Pu] for (TiN,PuN). The irradiated capsule was transported to Reactor Fuel Examination Facility and subjected to non-destructive and destructive post irradiation examinations. Any failure was not observed in the irradiated fuel pin. Very low fission gas release rate of about 1.6% was measured. The inner surface of cladding tube did not show any signs of chemical interaction with fuel pellet. (author)

  6. Plastic Trash goes Biohybrid"-Rapid and Selective Functionalization of Inert Plastic Surfaces with Biomolecules

    DEFF Research Database (Denmark)

    Schiller, Stefan M; Kambhampati, Dev; Stengel, Gudrun

    2010-01-01

    The covalent functionalization of "inert" polymers such as polypropylene with biomolecules for biocompatible or biosensor surfaces is challenging. Here we present a powerful approach to covalently modify "inert" macromolecular surfaces with biomacromolecules reusing old plastic material. A special...... emphasis was placed on easily accessible materials and a process which is easy, fast, efficient, cheap, and reliable. "Plastic trash" (lids from Eppendorf® pipet tip containers) was used as a polymer substrate to demonstrate the use/reuse of commercial packing material to covalently modify this material...

  7. Solvent-extraction methods applied to the chemical analysis of uranium. III. Study of the extraction with inert solvents; Metodos de extraccion con disolventes aplicados al analisis quimico del uranio. III. Estudio de la extraccion con disolvente inertes

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement Eguiluz, J C

    1964-07-01

    The extraction of uranium on the trace level is studied by using tributylphosphate as active agent under conditions aiming the attainment of quantitative extraction by means of a single step process using a number of salting-out agents and keeping inside the general lines as reported in two precedent papers. Two inert solvents were investigated, benzene and cyclohexane, which allowed to derive the corresponding empirical equations describing the extraction process and the results obtained were compared with those previously reported for solvents which, like ethyl acetate and methylisobuthylketone, favour to a more or less extend the extraction of uranium. (Author) 4 refs.

  8. Solvent extraction of uranium from high acid leach solution

    International Nuclear Information System (INIS)

    Ramadevi, G.; Sreenivas, T.; Navale, A.S.; Padmanabhan, N.P.H.

    2010-01-01

    A significant part of the total uranium reserves all over the world is contributed by refractory uranium minerals. The refractory oxides are highly stable and inert to attack by most of the commonly used acids under normal conditions of acid strength, pressure and temperature. Quantitative dissolution of uranium from such ores containing refractory uranium minerals requires drastic operating conditions during chemical leaching like high acid strength, elevated pressures and temperatures. The leach liquors produced under these conditions normally have high free acidity, which affects the downstream operations like ion exchange and solvent extraction

  9. Irradiation of inert matrix and mixed oxide fuel in the Halden test reactor

    International Nuclear Information System (INIS)

    Hellwig, Ch.; Kasemeyer, U.

    2001-01-01

    In a new type of fuel, called Inert Matrix Fuel (IMF), plutonium is embedded in a U-free matrix. This offers advantages for more efficient plutonium consumption, higher proliferation resistance, and for inert behaviour later in a waste repository. In the fuel type investigated at PSI, plutonium is dissolved in yttrium-stabilized zirconium oxide (YSZ), a highly radiation-resistant cubic phase, with addition of erbium as burnable poison for reactivity control. A first irradiation experiment of YSZ-based IMF is ongoing in the OECD Material Test Reactor in Halden (HBWR), together with MOX fuel (Rig IFA-651.1). The experiment is described herein and results are presented of the first 120 days of irradiation with an average assembly burnup of 47 kWd/cm 3 . The results are compared with neutronic calculations performed before the experiment, and are used to model the fuel behaviour with the PSI-modified TRANSURANUS code. The measured fuel temperatures are within the expected range. An unexpectedly strong densification of the IMF during the first irradiation cycle does not alter the fuel temperatures. An explanation for this behaviour is proposed. The irradiation at higher linear heat rates during forthcoming cycles will deliver information about the fission gas release behaviour of the IMF. (author)

  10. Irradiation of inert matrix and mixed oxide fuel in the Halden test reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hellwig, Ch.; Kasemeyer, U

    2001-03-01

    In a new type of fuel, called Inert Matrix Fuel (IMF), plutonium is embedded in a U-free matrix. This offers advantages for more efficient plutonium consumption, higher proliferation resistance, and for inert behaviour later in a waste repository. In the fuel type investigated at PSI, plutonium is dissolved in yttrium-stabilized zirconium oxide (YSZ), a highly radiation-resistant cubic phase, with addition of erbium as burnable poison for reactivity control. A first irradiation experiment of YSZ-based IMF is ongoing in the OECD Material Test Reactor in Halden (HBWR), together with MOX fuel (Rig IFA-651.1). The experiment is described herein and results are presented of the first 120 days of irradiation with an average assembly burnup of 47 kWd/cm{sup 3}. The results are compared with neutronic calculations performed before the experiment, and are used to model the fuel behaviour with the PSI-modified TRANSURANUS code. The measured fuel temperatures are within the expected range. An unexpectedly strong densification of the IMF during the first irradiation cycle does not alter the fuel temperatures. An explanation for this behaviour is proposed. The irradiation at higher linear heat rates during forthcoming cycles will deliver information about the fission gas release behaviour of the IMF. (author)

  11. Development and characterization of ceramic composites alumina-titania based reinforced with lanthanum oxide for fabrication of inert coatings for metallic tanks of the oil industry

    International Nuclear Information System (INIS)

    Bandeira, J.M.; Yadava, Y.P.; Silva, N.D.G.; Ferreira, R.A.S.

    2016-01-01

    Crude petroleum is highly corrosive causing superficial degradation in metallic tanks used for storage and transportation of this material, which causes a serious problem in the oil industry. An alternative to solve this problem is to use some kind of coating that is inert to this kind of corrosion. Alumina and titania are interesting materials for several engineering applications because, when compared with other ceramic materials, they present superior mechanical properties, e.g. high mechanical strength, good chemical stability and high fracture toughness combined with good wear resistance and a coefficient of thermal expansion close to the iron's, which makes them fit to use in ceramic hardening process and coating. In this paper, alumina-titania ceramic composites with 5%, 10%, 15% and 20% of titania (TiO2) and reinforced with 2% of lanthanum oxide of were produced by thermo-mechanical processing and sintering techniques at 1350 deg C. In these composites, microstructure and mechanical properties were analyzed using X-ray spectroscopy, optical microscopy, scanning electron microscopy and Vickers hardness in order to evaluate their applicability. X-ray spectroscopy showed the formation of composite without the presence of other phases. Optical microscopy and scanning electron microscopy showed a homogeneous microstructure in terms of particle size and distribution. Vickers hardness test showed a gradual decrease in hardness with the addition of titania. The composite with 5% of titania and 2% of lanthanum oxide is the best choice for structural applications. The composites were submerged in crude petroleum for 30 days to study their stability in such environment. Through the analysis of X-ray spectroscopy, optical microscopy and Vickers hardness before and after the submersion in crude petroleum, it was not observed structural or microstructural degradation nether alterations in mechanical properties. This way, it was concluded that these composites have good

  12. An investigation of the microstructures and properties of metal inert ...

    Indian Academy of Sciences (India)

    Abstract. Two different types of welds, Metal Inert Gas (MIG) and Friction Stir. Welding (FSW), have been used to weld aluminum alloy 5083. The microstructure of the welds, including the nugget zone and heat affected zone, has been compared in these two methods using optical microscopy. The mechanical properties of ...

  13. Seeded inert gas driven disk generator

    International Nuclear Information System (INIS)

    Joshi, N.K.; Venkatramani, N.; Rohatgi, V.K.

    1987-01-01

    This report outlines the present status of work being carried out in closed cycle MHD and disk generators. It gives the basic principles and discusses a proposal for setting up an experimental facility to study nonequilibrium plasmas using an inert gas driven disk generator. Disk geometry is a near ideal geometry for plasma studies since it has single or few pair electrodes combined with near perfect insulating walls. The proposed outlay of facility with components and subsystem is given. The facility may also be used to study the concept of fully ionized seed and to develop advanced diagnostic techniques. The absic equation describing the working parameters of such a system is also given in the Appendix. (author). 57 refs

  14. Inert doublet dark matter with an additional scalar singlet and 125 GeV Higgs boson

    Energy Technology Data Exchange (ETDEWEB)

    Dutta Banik, Amit; Majumdar, Debasish [Saha Institute of Nuclear Physics, Astroparticle Physics and Cosmology Division, Kolkata (India)

    2014-11-15

    In this work we consider a model for particle dark matter where an extra inert Higgs doublet and an additional scalar singlet is added to the Standard Model (SM) Lagrangian. The dark matter candidate is obtained from only the inert doublet. The stability of this one component dark matter is ensured by imposing a Z{sub 2} symmetry on this additional inert doublet. The additional singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard Model Higgs doublet, resulting in two CP even scalars h{sub 1} and h{sub 2}. We treat one of these scalars, h{sub 1}, to be consistent with the SM Higgs-like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars contribute to the annihilation cross section of this inert doublet dark matter, resulting in a larger dark matter mass region that satisfies the observed relic density. We also investigate the h{sub 1} → γγ and h{sub 1} → γ Z processes and compared these with LHC results. This is also used to constrain the dark matter parameter space in the present model. We find that the dark matter candidate in the mass region 60-80 GeV (m{sub 1} = 125 GeV, mass of h{sub 1}) satisfies the recent bound from LUX direct detection experiment. (orig.)

  15. Exploiting the plutonium stockpiles in PWRs by using inert matrix fuel

    International Nuclear Information System (INIS)

    Lombardi, C.; Mazzola, A.

    1996-01-01

    The plutonium coming from dismantled warheads and that already stockpiled coming from spent fuel reprocessing have raised many concerns related to proliferation resistance, environmental safety and economy. The option of disposing of plutonium by fission is one of the most widely discussed and many proposals for plutonium burning in a safe and economical manner have been put forward. Due to their diffusion, PWRs appear to be the main candidates for the reduction of the plutonium stockpiles. In order to achieve a high plutonium consumption rate, a uranium-free fuel may be conceived, based on the dilution of PuO 2 within a carrier matrix made of inert oxide. In this paper, a partial loading of inert matrix fuel in a current technology PWR was investigated with 3-D calculations. The results indicated that this solution has good plutonium elimination capabilities: commercial PWRs operating in a once-through cycle scheme can transmute more than 98% of the loaded Pu-239 and 73 or 81% of the overall initially loaded reactor grade or weapons grade plutonium, respectively. The plutonium still let in the spent fuel was of poor quality and then offered a better proliferation resistance. Power peaking problems could be faced with the adoption of burnable absorbers: IFBA seemed to be particularly suitable. In spite of a reduction of the overall plutonium loaded mass by a factor 3.7 or 5.4 depending on its quality, there was no evidence of an increase of the minor actinides radiotoxicity after a time period of about 25 years. (author)

  16. High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

    CSIR Research Space (South Africa)

    Boguslavsky, L

    2010-10-01

    Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

  17. Multisized Inert Particle Loading for Solid Rocket Axial Combustion Instability Suppression

    Directory of Open Access Journals (Sweden)

    David R. Greatrix

    2012-01-01

    Full Text Available In the present investigation, various factors and trends, related to the usage of two or more sets of inert particles comprised of the same material (nominally aluminum but at different diameters for the suppression of axial shock wave development, are numerically predicted for a composite-propellant cylindrical-grain solid rocket motor. The limit pressure wave magnitudes at a later reference time in a given pulsed firing simulation run are collected for a series of runs at different particle sizes and loading distributions and mapped onto corresponding attenuation trend charts. The inert particles’ presence in the central core flow is demonstrated to be an effective means of instability symptom suppression, in correlating with past experimental successes in the usage of particles. However, the predicted results of this study suggest that one needs to be careful when selecting more than one size of particle for a given motor application.

  18. Actinide transmutation using inert matrix fuels versus recycle in a low conversion fast burner reactor

    Energy Technology Data Exchange (ETDEWEB)

    Deinert, M.R.; Schneider, E.A.; Recktenwald, G.; Cady, K.B. [The Department of Mechanical Engineering, The University of Texas at Austin, 1 University Station, C2200, Austin, 78712 (United States)

    2009-06-15

    Reducing the disposal burden of the long lived radioisotopes that are contained within spent uranium oxide fuel is essential for ensuring the sustainability of nuclear power. Because of their non-fertile matrices, inert matrix fuels (IMFs) could allow light-water reactors to achieve a significant burn down of plutonium and minor actinides that are that are currently produced as a byproduct of operating light-water reactors. However, the extent to which this is possible is not yet fully understood. We consider a ZrO{sub 2} based IMF with a high transuranic loading and show that the neutron fluence (and the subsequent fuel residence time required to achieve it) present a practical limit for the achievable actinide burnup. The accumulation of transuranics in spent uranium oxide fuel is a major obstacle for the sustainability of nuclear power. While commercial light-water reactors (LWR's) produce these isotopes, they can be used to transmute them. At present, the only viable option for doing this is to partly fuel reactors with mixed oxide fuel (MOX) made using recycled plutonium. However, because of parasitic neutron capture in the uranium matrix of MOX, considerable plutonium and minor actinides are also bred as the fuel is burned. A better option is to entrain the recycled isotopes in a non-fertile matrix such as ZrO{sub 2}. Inert matrices such as these were originally envisioned for burning plutonium from dismantled nuclear weapons [1]. However, because they achieve a conversion ratio of zero, they have also been considered as a better alternative to MOX [2-6]. Plutonium and minor actinides dominate the long term heat and radiological outputs from spent nuclear fuel. Recent work has shown that that IMFs can be used to reduce these outputs by at least a factor of four, on a per unit of energy generated basis [6]. The degree of reduction is strongly dependent on IMF burnup. In principle, complete transmutation of the transuranics could be achieved though this

  19. Radiative neutrino mass and Majorana dark matter within an inert Higgs doublet model

    Science.gov (United States)

    Ahriche, Amine; Jueid, Adil; Nasri, Salah

    2018-05-01

    We consider an extension of the standard model (SM) with an inert Higgs doublet and three Majorana singlet fermions to address both origin and the smallness of neutrino masses and dark matter (DM) problems. In this setup, the lightest Majorana singlet fermion plays the role of DM candidate and the model parameter space can be accommodated to avoid different experimental constraints such as lepton flavor violating processes and electroweak precision tests. The neutrino mass is generated at one-loop level a la Scotogenic model and its smallness is ensured by the degeneracy between the C P -odd and C P -even scalar members of the inert doublet. Interesting signatures at both leptonic and hadronic colliders are discussed.

  20. Models of bending strength for Gilsocarbon graphites irradiated in inert and oxidising environments

    International Nuclear Information System (INIS)

    Eason, Ernest D.; Hall, Graham N.; Marsden, Barry J.; Heys, Graham B.

    2013-01-01

    This paper presents the development and validation of an empirical model of fast neutron damage and radiolytic oxidation effects on bending strength for the moulded Gilsocarbon graphites used in Advanced Gas-cooled Reactors (AGRs). The inert environment model is based on evidence of essentially constant strength as fast neutron dose increases in inert environment. The model of combined irradiation and oxidation calibrates that constant along with an exponential function representing the degree of radiolytic oxidation as measured by weight loss. The change in strength with exposure was found to vary from one AGR station to another. The model was calibrated to data on material trepanned from AGR moderator bricks after varying operating times

  1. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Pascual, M.; Salas, F.; Carcel, F.J.; Perales, M.; Sanchez, A.

    2010-07-01

    This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal. (Author). 12 refs.

  2. The Influence of Suspended Inert Solid Particles on Zinc Corrosion

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers

    1996-01-01

    The rate of corrosion of electroplated zinc in near-neutral chloride solutions can be lowered by as much as 75% by adding fine, inert particles of substances such as MnO2, Fe3O4, SiC and TiN to the well-stirred solution. Spreading of local areas of etching is also stopped. Copyright (C) 1996...

  3. An inert 3D emulsification device for individual precipitation and concentration of amorphous drug nanoparticles.

    Science.gov (United States)

    Lorenz, T; Bojko, S; Bunjes, H; Dietzel, A

    2018-02-13

    Nanosizing increases the specific surface of drug particles, leading to faster dissolution inside the organism and improving the bioavailability of poorly water-soluble drugs. A novel approach for the preparation of drug nanoparticles in water using chemically inert microfluidic emulsification devices is presented in this paper. A lithographic fabrication sequence was established, allowing fabrication of intersecting and coaxial channels of different depths in glass as is required for 3D flow-focusing. Fenofibrate was used as a model for active pharmaceutical ingredients with very low water solubility in the experiments. It was dissolved in ethyl acetate and emulsified in water, as allowed by the 3D flow-focusing geometry. In the thread formation regime, the drug solution turned into monodisperse droplets of sizes down to below 1 μm. Fast supersaturation occurs individually in each droplet, as the disperse phase solvent progressively diffuses into the surrounding water. Liquid antisolvent precipitation results in highly monodisperse and amorphous nanoparticles of sizes down to 128 nm which can be precisely controlled by the continuous and disperse phase pressure. By comparing optically measured droplet sizes with particle sizes by dynamic light scattering, we could confirm that exactly one particle forms in every droplet. Furthermore, a downstream on-chip concentration allowed withdrawal of major volumes of only the continuous phase fluid which enabled an increase of particle concentration by up to 250 times.

  4. Collider and dark matter searches in the inert doublet model from Peccei-Quinn symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Alexandre [Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo,Diadema-SP, 09972-270 (Brazil); Camargo, Daniel A.; Dias, Alex G. [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas,09210-580, Santo André-SP (Brazil); Longas, Robinson [Instituto de Física, Universidad de Antioquia,Calle 70 No. 52-21, Medellín (Colombia); Nishi, Celso C. [Universidade Federal do ABC, Centro de Matemática, Computação e Cognição Naturais,09210-580, Santo André-SP (Brazil); Queiroz, Farinaldo S. [Max-Planck-Institut fur Kernphysik,Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2016-10-04

    Weakly Interacting Massive Particles (WIMPs) and axions are arguably the most compelling dark matter candidates in the literature. Could they coexist as dark matter particles? More importantly, can they be incorporated in a well motivated framework in agreement with experimental data? In this work, we show that this two component dark matter can be realized in the Inert Doublet Model in an elegant and natural manner by virtue of the spontaneous breaking of a Peccei-Quinn U(1){sub PQ} symmetry into a residual ℤ{sub 2} symmetry. The WIMP stability is guaranteed by the ℤ{sub 2} symmetry and a new dark matter component, the axion, arises. There are two interesting outcomes: (i) vector-like quarks needed to implement the Peccei-Quinn symmetry in the model may act as a portal between the dark sector and the SM fields with a supersymmetry-type phenomenology at colliders; (ii) two-component Inert Doublet Model re-opens the phenomenologically interesting 100–500 GeV mass region. We show that the model can successfully realize a two component dark matter framework and at the same time avoid low and high energy physics constraints such as monojet and dijet plus missing energy, as well as indirect and direct dark matter detection bounds.

  5. Process for separation of inert fission gases for waste gas of a reprocessing plant for nuclear fuel

    International Nuclear Information System (INIS)

    Schnez, H.

    1980-01-01

    The inert fission gases Kr and Xe released in the resolver and other waste gases are taken to an acid regeneration plant. Part of the inert fission gases is separated by compression, cooling and filtering and deposited. The other part flows back to the resolver as flushing gas so that a flushing gas circuit is formed, which prevents explosive gas mixtures occurring. (DG) [de

  6. Inert gases in a terra sample - Measurements in six grain-size fractions and two single particles from Lunar 20.

    Science.gov (United States)

    Heymann, D.; Lakatos, S.; Walton, J. R.

    1973-01-01

    Review of the results of inert gas measurements performed on six grain-size fractions and two single particles from four samples of Luna 20 material. Presented and discussed data include the inert gas contents, element and isotope systematics, radiation ages, and Ar-36/Ar-40 systematics.

  7. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Directory of Open Access Journals (Sweden)

    Sánchez, A.

    2010-12-01

    Full Text Available This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal.

    En este estudio se analiza la influencia que el uso de una cámara de soldadura de gas inerte tiene sobre la microestructura y las propiedades mecánicas de las soldaduras TIG en el acero inoxidable austenítico AISI-316L cuando se emplean AISI ER316L, AISI 308L e Inconel 625 como materiales de aporte. Cuando se compara con el típico proceso de TIG, el uso de una cámara de gas inerte induce cambios en la microestructura, incrementando la presencia de ferrita vermicular y de laminillas de ferrita, resultando en un aumento del límite elástico y una pérdida de dureza. Su influencia sobre otras características de las soldaduras como la carga de rotura depende de la composición del material de aporte. La mejor combinación de propiedades mecánicas se obtuvo usando el Inconel 625 como material de aporte y soldando en la cámara de gas inerte.

  8. Solid-state reactions to synthesize nanostructured lead selenide semiconductor powders by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Chavez, H., E-mail: uu_gg_oo@yahoo.com.mx [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico) and Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - IPN, Legaria 694, Col. Irrigacion, Del. Miguel Hidalgo (Mexico); Reyes-Carmona, F. [Facultad de Quimica - UNAM, Circuito de la Investigacion Cientifica s/n, C.U. Del. Coyoacan (Mexico); Jaramillo-Vigueras, D. [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico)

    2011-10-15

    Highlights: {yields} PbSe synthesized from PbO instead of Pb powder do not require an inert atmosphere. {yields} During high-energy milling oxygen has to be chemically reduced from the lead oxide. {yields} Solid-state and solid-gas chemical reactions promote both solid and gaseous products. -- Abstract: Both solid-solid and gas-solid reactions have been traced during high-energy milling of Se and PbO powders under vial (P, T) conditions in order to synthesize the PbSe phase. Chemical and thermodynamic arguments are postulated to discern the high-energy milling mechanism to transform PbO-Se micropowders onto PbSe-nanocrystals. A set of reactions were evaluated at around room temperature. Therefore an experimental campaign was designed to test the nature of reactions in the PbO-Se system during high-energy milling.

  9. Solid-state reactions to synthesize nanostructured lead selenide semiconductor powders by high-energy milling

    International Nuclear Information System (INIS)

    Rojas-Chavez, H.; Reyes-Carmona, F.; Jaramillo-Vigueras, D.

    2011-01-01

    Highlights: → PbSe synthesized from PbO instead of Pb powder do not require an inert atmosphere. → During high-energy milling oxygen has to be chemically reduced from the lead oxide. → Solid-state and solid-gas chemical reactions promote both solid and gaseous products. -- Abstract: Both solid-solid and gas-solid reactions have been traced during high-energy milling of Se and PbO powders under vial (P, T) conditions in order to synthesize the PbSe phase. Chemical and thermodynamic arguments are postulated to discern the high-energy milling mechanism to transform PbO-Se micropowders onto PbSe-nanocrystals. A set of reactions were evaluated at around room temperature. Therefore an experimental campaign was designed to test the nature of reactions in the PbO-Se system during high-energy milling.

  10. Optical and Chemical Characterization of Aerosols Produced from Cooked Meats

    Science.gov (United States)

    Niedziela, R. F.; Foreman, E.; Blanc, L. E.

    2011-12-01

    Cooking processes can release a variety compounds into the air immediately above a cooking surface. The distribution of compounds will largely depend on the type of food that is being processed and the temperatures at which the food is prepared. High temperatures release compounds from foods like meats and carry them away from the preparation surface into cooler regions where condensation into particles can occur. Aerosols formed in this manner can impact air quality, particularly in urban areas where the amount of food preparation is high. Reported here are the results of laboratory experiments designed to optically and chemically characterize aerosols derived from cooking several types of meats including ground beef, salmon, chicken, and pork both in an inert atmosphere and in synthetic air. The laboratory-generated aerosols are studied using a laminar flow cell that is configured to accommodate simultaneous optical characterization in the mid-infrared and collection of particles for subsequent chemical analysis by gas chromatography. Preliminary optical results in the visible and ultra-violet will also be presented.

  11. Arc melting in inert gas atmosphere of zirconium sponge

    International Nuclear Information System (INIS)

    Julio Junior, O.; Andrade, A.H.P. de

    1991-01-01

    The obtainment of metallic zirconium in laboratory scale with commercial and nuclear quality is the objective of the Metallurgy Department of IEN/CNEN - Brazil, so a melting procedure of zirconium sponge in laboratory scale using an arc furnace in inert atmosphere is developed. The effects of atmosphere operation, and the use of gas absorber and the sponge characteristics over the quality of button in as-cast reporting with hardness measures are described. (C.G.C.)

  12. Endotracheal tube resistance and inertance in a model of mechanical ventilation of newborns and small infants—the impact of ventilator settings on tracheal pressure swings

    International Nuclear Information System (INIS)

    Hentschel, Roland; Buntzel, Julia; Guttmann, Josef; Schumann, Stefan

    2011-01-01

    Resistive properties of endotracheal tubes (ETTs) are particularly relevant in newborns and small infants who are generally ventilated through ETTs with a small inner diameter. The ventilation rate is also high and the inspiratory time (ti) is short. These conditions effectuate high airway flows with excessive flow acceleration, so airway resistance and inertance play an important role. We carried out a model study to investigate the impact of varying ETT size, lung compliance and ventilator settings, such as peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP) and inspiratory time (ti) on the pressure–flow characteristics with respect to the resistive and inertive properties of the ETT. Pressure at the Y piece was compared to direct measurement of intratracheal pressure (P trach ) at the tip of the ETT, and pressure drop (ΔP ETT ) was calculated. Applying published tube coefficients (Rohrer's constants and inertance), P trach was calculated from ventilator readings and compared to measured P trach using the root-mean-square error. The most relevant for ΔP ETT was the ETT size, followed by (in descending order) PIP, compliance, ti and PEEP, with gas flow velocity being the principle in common for all these parameters. Depending on the ventilator settings ΔP ETT exceeded 8 mbar in the smallest 2.0 mm ETT. Consideration of inertance as an additional effect in this setting yielded a better agreement of calculated versus measured P trach than Rohrer's constants alone. We speculate that exact tracheal pressure tracings calculated from ventilator readings by applying Rohrer's equation and the inertance determination to small size ETTs would be helpful. As an integral part of ventilator software this would (1) allow an estimate of work of breathing and implementation of an automatic tube compensation, and (2) be important for gentle ventilation in respiratory care, especially of small infants, since it enables the physician to

  13. Vector boson fusion in the inert doublet model

    Science.gov (United States)

    Dutta, Bhaskar; Palacio, Guillermo; Restrepo, Diego; Ruiz-Álvarez, José D.

    2018-03-01

    In this paper we probe the inert Higgs doublet model at the LHC using vector boson fusion (VBF) search strategy. We optimize the selection cuts and investigate the parameter space of the model and we show that the VBF search has a better reach when compared with the monojet searches. We also investigate the Drell-Yan type cuts and show that they can be important for smaller charged Higgs masses. We determine the 3 σ reach for the parameter space using these optimized cuts for a luminosity of 3000 fb-1 .

  14. Possible 85Kr influence on the plant metabolism. Investigation of inert gas 85Kr interaction with plants

    International Nuclear Information System (INIS)

    Butkus, D.

    1999-01-01

    Model experiments have shown that inert gas 85 Kr is accumulated by plants. The aim of the work was to determine the way of the capture of inert gas by growing plants: either only through their overground part from air or in addition through their overground part from air or in addition through roots which accumulate water dissolved materials. For this purpose potatoes were grown in the chamber where the 85 Kr volume activity was (3.6±0.1)*10 6 Bq*m -3 . It was determined that 85 Kr gas accumulation was greater in those plant parts which grow faster and are further from the soil. Measurement results of 85 Kr activity of a potato tuber slightly differed from the environment background activity. It shows that the main penetration of inert gas into the plant occurred by absorption from air. (author)

  15. Fabrication of Miniature Titanium Capsule for Brachytherapy Sources Using Tungsten Inert Gas Method

    International Nuclear Information System (INIS)

    Naghdi, R.; Sheibani, Sh.; Tamizifar, M.

    2013-01-01

    The capsules containing radioactive materials as brachytherapy sources are used for implanting into some target organs for malignant disorders treatments, such as prostate, eyes, and brain cancers. The conventional method for sealing the tubes is to weld them using a laser beam which is now a part of tube melting methods (self welding). The purpose of this study was to seal miniature titanium tubes containing radioactive materials in the form of capsules. This study introduced a new method based on melting process. A piece of commercially pure titanium grade 2 in the form of disk was used for the experiment. The sample was melted at the top of the tube by a Tungsten Inert Gas welding device for a short time duration. After completion of the melting, the disk in the form of a drop was mixed with a small part of it and both were solidified and hence closed the tube. We evaluated the tubes for the metallurgical properties and seal process which took place by Tungsten Inert Gas in different zones, including the heat affected zone, fusion zone, and interface of the joint of the drop to the tube. Finally, the produced samples were tested according to the ISO2919 and ISO9978 and the results confirmed the Disk and Tungsten Inert Gas procedure.

  16. Demand-Based Optimal Design of Storage Tank with Inerter System

    Directory of Open Access Journals (Sweden)

    Shiming Zhang

    2017-01-01

    Full Text Available A parameter optimal design method for a tank with an inerter system is proposed in this study based on the requirements of tank vibration control to improve the effectiveness and efficiency of vibration control. Moreover, a response indicator and a cost control indicator are selected based on the control targets for liquid storage tanks for simultaneously minimizing the dynamic response and controlling costs. These indicators are reformulated through a random vibration analysis under virtual excitation. The problem is then transformed from a multiobjective optimization problem to a single-objective nonlinear problem using the ε-constraint method, which is consistent with the demand-based method. White noise excitation can be used to design the tank with the inerter system under seismic excitation to simplify the calculation. Subsequently, a MATLAB-based calculation program is compiled, and several optimization cases are examined under different excitation conditions. The effectiveness of the demand-based method is proven through a time history analysis. The results show that specific vibration control requirements can be met at the lowest cost with a simultaneous reduction in base shears and overturning base moments.

  17. Process safety management for highly hazardous chemicals

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    Purpose of this document is to assist US DOE contractors who work with threshold quantities of highly hazardous chemicals (HHCs), flammable liquids or gases, or explosives in successfully implementing the requirements of OSHA Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119). Purpose of this rule is to prevent releases of HHCs that have the potential to cause catastrophic fires, explosions, or toxic exposures.

  18. Using fumarolic inert gas composition to investigate magma dynamics at Campi Flegrei (Italy)

    Science.gov (United States)

    Chiodini, G.; Caliro, S.; Paonita, A.; Cardellini, C.

    2013-12-01

    Since 2000 the Campi Flegrei caldera sited in Neapolitan area (Italy), has showed signs of reactivation, marked by ground uplift, seismic activity, compositional variations of fumarolic effluents from La Solfatara, an increase of the fumarolic activity as well as of soil CO2 fluxes. Comparing long time series of geochemical signals with ground deformation and seismicity, we show that these changes are at least partially caused by repeated injections of magmatic fluid into the hydrothermal system. The frequency of these degassing episodes has increased in the last years, causing pulsed uplift episodes and swarms of low magnitude earthquakes. We focus here in the inert gas species (CO2-He-Ar-N2) of Solfatara fumaroles which displayed in the time spectacular and persistent variation trends affecting all the monitored vents. The observed variations, which include a continuous decrease of both N2/He and N2/CO2 ratios since 1985, paralleled by an increase of He/CO2, can not be explained neither with changes in processes of boiling-condensation in the local hydrothermal system nor with changes in the mixing proportions between a magmatic vapour and hydrothermal fluids. Consequently we investigated the possibility that the trends of inert gas species are governed by changes in the conditions controlling magma degassing at depth. We applied a magma degassing model, with the most recent updates for inert gas solubilities, after to have included petrologic constraints from the ranges of melt composition and reservoir pressure at Campi Flegrei. The model simulations for mafic melts (trachybasalt and shoshonite) show a surprising agreement with the measured data. Both decompressive degassing of an ascending magma and mixing between magmatic fluids exsolved at various levels along the ascent path can explain the long-time geochemical changes. Our work highlights that, in caldera systems where the presence of hydrothermal aquifers commonly masks the magmatic signature of reactive

  19. 76 FR 1067 - Testing of Certain High Production Volume Chemicals; Second Group of Chemicals

    Science.gov (United States)

    2011-01-07

    ... Mfg & NOES (number based criteria based criteria significant chemicals (lbs) industrial of workers... 2070-AD16 Testing of Certain High Production Volume Chemicals; Second Group of Chemicals AGENCY... section 4(a)(1)(B) of the Toxic Substances Control Act (TSCA) to require manufacturers, importers, and...

  20. The Production of Polycyclic Aromatic Hydrocarbon Anions in Inert Gas Matrices Doped with Alkali Metals. Electronic Absorption Spectra of the Pentacene Anion (C22H14(-))

    Science.gov (United States)

    Halasinski, Thomas M.; Hudgins, Douglas M.; Salama, Farid; Allamandola, Louis J.; Mead, Susan (Technical Monitor)

    1999-01-01

    The absorption spectra of pentacene (C22H14) and its radical cation (C22H14(+)) and anion (C22H14(-)) isolated in inert-gas matrices of Ne, Ar, and Kr are reported from the ultraviolet to the near-infrared. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing ion (and counterion) production in the solid matrix. In particular, the formation of isolated pentacene anions is found to be optimized in matrices doped with alkali metal (Na and K).

  1. Inerting Aircraft Fuel Systems Using Exhaust Gases

    Science.gov (United States)

    Hehemann, David G.

    2002-01-01

    Our purpose in this proposal was to determine the feasibility of using carbon dioxide, possibly obtained from aircraft exhaust gases as a substance to inert the fuel contained in fuel tanks aboard aircraft. To do this, we decided to look at the effects carbon dioxide has upon commercial Jet-A aircraft fuel. In particular, we looked at the solubility of CO2 in Jet-A fuel, the pumpability of CO2-saturated Jet-A fuel, the flashpoint of Jet-A fuel under various mixtures of air and CO2, the static outgassing of CO2-Saturated Jet-A fuel and the dynamic outgassing of Jet-A fuel during pumping of Jet-A fuel.

  2. Development and characterization of solidified forms for high-level wastes: 1978. Annual report

    International Nuclear Information System (INIS)

    Ross, W.A.; Mendel, J.E.

    1979-12-01

    Development and characterization of solidified high-level waste forms are directed at determining both process properties and long-term behaviors of various solidified high-level waste forms in aqueous, thermal, and radiation environments. Waste glass properties measured as a function of composition were melt viscosity, melt electrical conductivity, devitrification, and chemical durability. The alkali metals were found to have the greatest effect upon glass properties. Titanium caused a slight decrease in viscosity and a significant increase in chemical durability in acidic solutions (pH-4). Aluminum, nickel and iron were all found to increase the formation of nickel-ferrite spinel crystals in the glass. Four multibarrier advanced waste forms were produced on a one-liter scale with simulated waste and characterized. Glass marbles encapsulated in a vacuum-cast lead alloy provided improved inertness with a minimal increase in technological complexity. Supercalcine spheres exhibited excellent inertness when coated with pyrolytic carbon and alumina and put in a metal matrix, but the processing requirements are quite complex. Tests on simulated and actual high-level waste glasses continue to suggest that thermal devitrification has a relatively small effect upon mechanical and chemical durabilities. Tests on the effects radiation has upon waste forms also continue to show changes to be relatively insignificant. Effects caused by decay of actinides can be estimated to saturate at near 10 19 alpha-events/cm 3 in homogeneous solids. Actually, in solidified waste forms the effects are usually observed around certain crystals as radiation causes amorphization and swelling of th crystals

  3. Modeling the effects of size on patch dynamics of an inert tracer

    Directory of Open Access Journals (Sweden)

    P. Xiu

    2010-03-01

    Full Text Available Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited observational capability and complex of physical processes. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

  4. The role of "inert" surface chemistry in marine biofouling prevention.

    Science.gov (United States)

    Rosenhahn, Axel; Schilp, Sören; Kreuzer, Hans Jürgen; Grunze, Michael

    2010-05-07

    The settlement and colonization of marine organisms on submerged man-made surfaces is a major economic problem for many marine industries. The most apparent detrimental effects of biofouling are increased fuel consumption of ships, clogging of membranes and heat exchangers, disabled underwater sensors, and growth of biofoulers in aquaculture systems. The presently common-but environmentally very problematic-way to deal with marine biofouling is to incorporate biocides, which use biocidal products in the surface coatings to kill the colonizing organisms, into the surface coatings. Since the implementation of the International Maritime Organization Treaty on biocides in 2008, the use of tributyltin (TBT) is restricted and thus environmentally benign but effective surface coatings are required. In this short review, we summarize the different strategies which are pursued in academia and industry to better understand the mechanisms of biofouling and to develop strategies which can be used for industrial products. Our focus will be on chemically "inert" model surface coatings, in particular oligo- and poly(ethylene glycol) (OEG and PEG) functionalized surface films. The reasons for choosing this class of chemistry as an example are three-fold: Firstly, experiments on spore settlement on OEG and PEG coatings help to understand the mechanism of non-fouling of highly hydrated interfaces; secondly, these studies defy the common assumption that surface hydrophilicity-as measured by water contact angles-is an unambiguous and predictive tool to determine the fouling behavior on the surface; and thirdly, choosing this system is a good example for "interfacial systems chemistry": it connects the behavior of unicellular marine organisms with the antifouling properties of a hydrated surface coating with structural and electronic properties as derived from ab initio quantum mechanical calculations using the electronic wave functions of oxygen, hydrogen, and carbon. This short

  5. Use of uranyl nitrate as a shift reagent in polar and inert solvents

    International Nuclear Information System (INIS)

    Nosov, B.P.

    1988-01-01

    This work examines the effect of uranyl nitrate as a shift reagent on the PMR spectra of different organic molecules in polar and inert solvents. In order to identify the coordination site of the uranyl ion, its effect on the spectra of amino acids and acetic or propionic acids in water was compared. It was found that the induced shifts of the protons in the corresponding positions of the different acids after addition of uranyl nitrate agreed to within ±0.01 ppm. When nitrogenous bases such as diethylamine and pyridine were added to solutions of the carboxylic acids with uranyl nitrate, an increase in the induced chemical shift of the resonance signals occurred. These facts suggest the coordination of the uranyl ion with the carboxyl oxygen both for acetic and propionic acids and for amino acids. The authors established that the addition of uranyl nitrate to solutions of organic compounds caused different downfield shifts of the resonance signals from the protons. In polar solvents shifts induced by uranyl nitrate in the PMR spectra of carboxylic acids occur only when nitrogenous bases are added

  6. The relationship between chemical structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Hao [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States)]. E-mail: hao.jiang@wpafb.af.mil; Hong Lianggou [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States); Venkatasubramanian, N. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Grant, John T. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Eyink, Kurt [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Wiacek, Kevin [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Fries-Carr, Sandra [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Enlow, Jesse [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Bunning, Timothy J. [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States)

    2007-02-26

    Polymer dielectric films fabricated by plasma enhanced chemical vapor deposition (PECVD) have unique properties due to their dense crosslinked bulk structure. These spatially uniform films exhibit good adhesion to a variety of substrates, excellent chemical inertness, high thermal resistance, and are formed from an inexpensive, solvent-free, room temperature process. In this work, we studied the dielectric properties of plasma polymerized (PP) carbon-based polymer thin films prepared from two precursors, benzene and octafluorocyclobutane. Two different monomer feed locations, directly in the plasma zone or in the downstream region (DS) and two different pressures, 80 Pa (high pressure) or 6.7 Pa (low pressure), were used. The chemical structure of the PECVD films was examined by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The dielectric constant ({epsilon} {sub r}) and dielectric loss (tan {delta}) of the films were investigated over a range of frequencies up to 1 MHz and the dielectric strength (breakdown voltage) (F {sub b}) was characterized by the current-voltage method. Spectroscopic ellipsometry was performed to determine the film thickness and refractive index. Good dielectric properties were exhibited, as PP-benzene films formed in the high pressure, DS region showed a F{sub b} of 610 V/{mu}m, an {epsilon} {sub r} of 3.07, and a tan {delta} of 7.0 x 10{sup -3} at 1 kHz. The PECVD processing pressure has a significant effect on final film structure and the film's physical density has a strong impact on dielectric breakdown strength. Also noted was that the residual oxygen content in the PP-benzene films significantly affected the frequency dependences of the dielectric constant and loss.

  7. The relationship between chemical structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films

    International Nuclear Information System (INIS)

    Jiang Hao; Hong Lianggou; Venkatasubramanian, N.; Grant, John T.; Eyink, Kurt; Wiacek, Kevin; Fries-Carr, Sandra; Enlow, Jesse; Bunning, Timothy J.

    2007-01-01

    Polymer dielectric films fabricated by plasma enhanced chemical vapor deposition (PECVD) have unique properties due to their dense crosslinked bulk structure. These spatially uniform films exhibit good adhesion to a variety of substrates, excellent chemical inertness, high thermal resistance, and are formed from an inexpensive, solvent-free, room temperature process. In this work, we studied the dielectric properties of plasma polymerized (PP) carbon-based polymer thin films prepared from two precursors, benzene and octafluorocyclobutane. Two different monomer feed locations, directly in the plasma zone or in the downstream region (DS) and two different pressures, 80 Pa (high pressure) or 6.7 Pa (low pressure), were used. The chemical structure of the PECVD films was examined by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The dielectric constant (ε r ) and dielectric loss (tan δ) of the films were investigated over a range of frequencies up to 1 MHz and the dielectric strength (breakdown voltage) (F b ) was characterized by the current-voltage method. Spectroscopic ellipsometry was performed to determine the film thickness and refractive index. Good dielectric properties were exhibited, as PP-benzene films formed in the high pressure, DS region showed a F b of 610 V/μm, an ε r of 3.07, and a tan δ of 7.0 x 10 -3 at 1 kHz. The PECVD processing pressure has a significant effect on final film structure and the film's physical density has a strong impact on dielectric breakdown strength. Also noted was that the residual oxygen content in the PP-benzene films significantly affected the frequency dependences of the dielectric constant and loss

  8. Determination of Heritage SSME Pogo Suppressor Resistance and Inertance from Waterflow Pulse Testing

    Science.gov (United States)

    McDougal, Chris; Eberhart, Chad; Lee, Erik

    2016-01-01

    Waterflow tests of a heritage Space Shuttle Main Engine pogo suppressor were performed to experimentally quantify the resistance and inertance provided by the suppressor. Measurements of dynamic pressure and flow rate in response to pulsing flow were made throughout the test loop. A unique system identification methodology combined all sensor measurements with a one-dimensional perturbational flow model of the complete water flow loop to spatially translate physical measurements to the device under test. Multiple techniques were then employed to extract the effective resistance and inertance for the pogo suppressor. Parameters such as steady flow rate, perturbational flow rate magnitude, and pulse frequency were investigated to assess their influence on the behavior of the pogo suppressor dynamic response. These results support validation of the RS-25 pogo suppressor performance for use on the Space Launch System Core Stage.

  9. Performance Specification Shippinpark Pressurized Water Reactor Fuel Drying and Canister Inerting System for PWR Core 2 Blanket Fuel Assemblies Stored within Shippingport Spent Fuel Canisters

    International Nuclear Information System (INIS)

    JOHNSON, D.M.

    2000-01-01

    This specification establishes the performance requirements and basic design requirements imposed on the fuel drying and canister inerting system for Shippingport Pressurized Water Reactor (PWR) Core 2 blanket fuel assemblies (BFAs) stored within Shippingport spent fuel (SSFCs) canisters (fuel drying and canister inerting system). This fuel drying and canister inerting system is a component of the U.S. Department of Energy, Richland Operations Office (RL) Spent Nuclear Fuels Project at the Hanford Site. The fuel drying and canister inerting system provides for removing water and establishing an inert environment for Shippingport PWR Core 2 BFAs stored within SSFCs. A policy established by the U.S. Department of Energy (DOE) states that new SNF facilities (this is interpreted to include structures, systems and components) shall achieve nuclear safety equivalence to comparable U.S. Nuclear Regulatory Commission (NRC)-licensed facilities. This will be accomplished in part by applying appropriate NRC requirements for comparable NRC-licensed facilities to the fuel drying and canister inerting system, in addition to applicable DOE regulations and orders

  10. The inert doublet model in the light of Fermi-LAT gamma-ray data: a global fit analysis

    Science.gov (United States)

    Eiteneuer, Benedikt; Goudelis, Andreas; Heisig, Jan

    2017-09-01

    We perform a global fit within the inert doublet model taking into account experimental observables from colliders, direct and indirect dark matter searches and theoretical constraints. In particular, we consider recent results from searches for dark matter annihilation-induced gamma-rays in dwarf spheroidal galaxies and relax the assumption that the inert doublet model should account for the entire dark matter in the Universe. We, moreover, study in how far the model is compatible with a possible dark matter explanation of the so-called Galactic center excess. We find two distinct parameter space regions that are consistent with existing constraints and can simultaneously explain the excess: One with dark matter masses near the Higgs resonance and one around 72 GeV where dark matter annihilates predominantly into pairs of virtual electroweak gauge bosons via the four-vertex arising from the inert doublet's kinetic term. We briefly discuss future prospects to probe these scenarios.

  11. The inert doublet model in the light of Fermi-LAT gamma-ray data: a global fit analysis

    Energy Technology Data Exchange (ETDEWEB)

    Eiteneuer, Benedikt; Heisig, Jan [RWTH Aachen University, Institute for Theoretical Particle Physics and Cosmology, Aachen (Germany); Goudelis, Andreas [UMR 7589 CNRS and UPMC, Laboratoire de Physique Theorique et Hautes Energies (LPTHE), Paris (France)

    2017-09-15

    We perform a global fit within the inert doublet model taking into account experimental observables from colliders, direct and indirect dark matter searches and theoretical constraints. In particular, we consider recent results from searches for dark matter annihilation-induced gamma-rays in dwarf spheroidal galaxies and relax the assumption that the inert doublet model should account for the entire dark matter in the Universe. We, moreover, study in how far the model is compatible with a possible dark matter explanation of the so-called Galactic center excess. We find two distinct parameter space regions that are consistent with existing constraints and can simultaneously explain the excess: One with dark matter masses near the Higgs resonance and one around 72 GeV where dark matter annihilates predominantly into pairs of virtual electroweak gauge bosons via the four-vertex arising from the inert doublet's kinetic term. We briefly discuss future prospects to probe these scenarios. (orig.)

  12. Identification of market bags composition for biodegradable and oxo-biodegradable samples through thermal analysis in inert and oxidizer atmosphere; Identificacao da composicao de amostras de sacolas plasticas biodegradaveis e oxobiodegradaveis atraves de analises termicas em atmosfera inerte e oxidante

    Energy Technology Data Exchange (ETDEWEB)

    Finzi-Quintao, Cristiane M., E-mail: inzi@ufsj.edu.br [Universidade Federal de Sao Joao del-Rei (UFSJ), MG (Brazil); Novack, Katia M. [Universidade Federal de Ouro Preto (DEQUI/UFOP), MG (Brazil)

    2015-07-01

    Plastic films used to make market bags are based on polymers such as polyethylene, polystyrene and polypropylene, these materials require a long time to degrade in the environment. The alternative technologies of polymers have been developed to reduce the degradation time and the impact on the environment caused by the conventional materials, using pro-degrading additives or by the development biodegradable polymers. In Brazil, the laws of some municipalities require the use of biodegradable material in the production of market bags but the absence of specific surveillance policies makes its chemical composition unknown. In this paper, we analyzed 7 samples that was obtained from a a trading company and commercial market of Belo Horizonte . The samples were characterized by TGA / DTA , XRF , FTIR and MEV which allowed the identification and evaluation of the thermal behavior of the material in inert and oxidizing atmosphere. (author)

  13. Chemical reactions in solvents and melts

    CERN Document Server

    Charlot, G

    1969-01-01

    Chemical Reactions in Solvents and Melts discusses the use of organic and inorganic compounds as well as of melts as solvents. This book examines the applications in organic and inorganic chemistry as well as in electrochemistry. Organized into two parts encompassing 15 chapters, this book begins with an overview of the general properties and the different types of reactions, including acid-base reactions, complex formation reactions, and oxidation-reduction reactions. This text then describes the properties of inert and active solvents. Other chapters consider the proton transfer reactions in

  14. Observability of inert scalars at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, Majid [Shiraz University, Physics Department, College of Sciences, Shiraz (Iran, Islamic Republic of); Najjari, Saereh [University of Warsaw, Faculty of Physics, Warsaw (Poland)

    2017-09-15

    In this work we investigate the observability of inert doublet model scalars at the LHC operating at the center of mass energy of 14 TeV. The signal production process is pp → AH{sup ±} → ZHW{sup ±}H leading to two different final states of l{sup +}l{sup -}HjjH and l{sup +}l{sup -}Hl{sup ±}νH based on the hadronic and leptonic decay channels of the W boson. All the relevant background processes are considered and an event selection is designed to distinguish the signal from the large Standard Model background. We found that signals of the selected search channels are well observable at the LHC with an integrated luminosity of 300 fb{sup -1}. (orig.)

  15. Collision-induced polarizabilities of inert gas atoms

    International Nuclear Information System (INIS)

    Clarke, K.L.; Madden, P.A.; Buckingham, A.D.

    1978-01-01

    The use of polarizability densities to calculate collision-induced polarizabilities is investigated. One method for computing polarizabilities of inert gas diatoms employs atomic polarizability densities from finite-field Hartree-Fock calculations, together with classical equations for the polarization of dielectrics. It is shown that this model gives inaccurate values for both the local fields and the local response to non-uniform fields. An alternative method incorporating the same physical effects is used to compute the pair polarizabilities to first order in the interatomic interaction. To first order the pair contribution to the trace of the polarizability is negative at short range. The calculated anisotropy does not differ significantly from the DID value, whereas the polarizability density calculation gives a substantial reduction in the anisotropy. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-10

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

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

    International Nuclear Information System (INIS)

    Yang Ting; Lua, Aik Chong

    2006-01-01

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

  18. WVNS Tank Farm Process Support: Experimental evaluation of an inert gas (nitrogen) to mitigate external corrosion of high-level waste storage tanks

    International Nuclear Information System (INIS)

    Elmore, M.R.

    1996-02-01

    Corrosion of the carbon steel waste storage tanks at West Valley Nuclear Services continues to be of concern, especially as the planned duration of waste storage time increases and sludge washing operations are conducted. The external surfaces of Tanks 8D-1 and 8D-2 have been exposed for more than 10 years to water that has intruded into the tank vaults. Visual inspection of the external tank surfaces using a remote video camera has shown indications of heavy corrosion in localized areas on the tank walls. Tests on mild steel specimens under simulated tank vault conditions showed that corrosion is related to the availability of oxygen for the corrosion reactions; consequently, removing oxygen as one of the reactants should effectively eliminate corrosion. In terms of the waste tanks, excluding oxygen from the annular vault space, such as by continuous flushing with an inert gas, should substantially decrease corrosion of the external surfaces of the mild steel tanks (100% exclusion of oxygen is probably not practicable). Laboratory corrosion testing was conducted at Pacific Northwest National Laboratory to give a preliminary assessment of the ability of nitrogen-inerting to reduce steel corrosion. This report summarizes test results obtained after 18-month corrosion tests comparing open-quotes nitrogen-inertedclose quotes corrosion with open-quotes air-equilibratedclose quotes corrosion under simulated tank vault conditions

  19. Re-derived overclosure bound for the inert doublet model

    Science.gov (United States)

    Biondini, S.; Laine, M.

    2017-08-01

    We apply a formalism accounting for thermal effects (such as modified Sommerfeld effect; Salpeter correction; decohering scatterings; dissociation of bound states), to one of the simplest WIMP-like dark matter models, associated with an "inert" Higgs doublet. A broad temperature range T ˜ M/20 . . . M/104 is considered, stressing the importance and less-understood nature of late annihilation stages. Even though only weak interactions play a role, we find that resummed real and virtual corrections increase the tree-level overclosure bound by 1 . . . 18%, depending on quartic couplings and mass splittings.

  20. Transcatheter embolization of renal neoplasms. A comparison of the merits of the radio-active infarct implant versus total embolization with inert material

    International Nuclear Information System (INIS)

    Lang, E.K.; Pisco, J.M.

    1980-01-01

    Transcatheter embolization with radio-active infarct particles and inert embolic material has been proposed for adjuvant therapy in the management of renal cell carcinoma. Transcatheter embolization with inert embolic material has been advocated in preparation for surgical resection of renal tumours. Embolization with radio-active infarct particles is undertaken to deliver a tumouricidal dose to the primary neoplasm. The resultant interstitial implant offers the advantage of a high dose to the primary tumour, choice of time of delivery of the radiant energy by selection of a radio-isotope with appropriate half-life, and limitation of the integral dose to the patient by selection of appropriate physical characteristics of the radio-isotope utilized. Transcatheter embolization with radio-active infarct particles is advocated either as definitive therapy for clearly inoperable neoplasms, or in hope to make an initially inoperable neoplasm operable. (Auth.)

  1. Chemical treatment and biomimetic coating evaluating in zirconia-alumina ceramics

    International Nuclear Information System (INIS)

    Aguiar, Amanda Abati

    2007-01-01

    Ceramic materials, as alumina and zirconia have been explored along the years as biomaterials application. The bio inert nature has been stimulating the development of new alternatives, as chemical treatments to improve the biological application of these ceramics. The biomimetic process of bio inert ceramics for coating apatite is based on soaking the implant in a simulated body fluid, SBF, with ion concentrations nearly equal to those of human blood plasma. The bioactivity of the material is related with the formation of a layer constituted of hydroxyapatite low crystalline, similar to the biological apatite. The biocompatibility associated to the structural properties of the alumina and zirconia has been stimulating the clinical use of these materials, mainly in areas of larger mechanical requests, places not recommended for bioactive hydroxyapatite, for instance. In this work samples of alumina, zirconia doped with Yttria (3% mol) and composites of alumina and zirconia doped with Yttria (3% mol) were prepared by co-precipitation method, calcinate, sintered, chemically treated with solutions of acid phosphoric and sodium hydroxide and them immersed in 1.0 M and 1.5 M SBF. The calcinate powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), gas adsorption (BET) and laser diffraction. The XRD results indicate that the samples are low crystalline. It was observed for BET that the samples present high specific surface area. The results of laser diffraction and SEM showed that the powders are agglomerates. The sintered samples were analyzed by XRD, SEM and X-ray fluorescence (XRF). The phases quantified by Rietveld method were: cubic, tetragonal and monoclinic of the zirconia, besides the phase alpha of the alumina. The chemical treatment with phosphoric acid didn't present a tendency of larger apatite formation in relation to the samples no chemically treated. The treatment with sodium hydroxide provoked accentuated transformation of

  2. Fibre Laser Cutting and Chemical Etching of AZ31 for Manufacturing Biodegradable Stents

    Directory of Open Access Journals (Sweden)

    Ali Gökhan Demir

    2013-01-01

    Full Text Available The use of magnesium-alloy stents shows promise as a less intrusive solution for the treatment of cardiovascular pathologies as a result of the high biocompatibility of the material and its intrinsic dissolution in body fluids. However, in addition to requiring innovative solutions in material choice and design, these stents also require a greater understanding of the manufacturing process to achieve the desired quality with improved productivity. The present study demonstrates the manufacturing steps for the realisation of biodegradable stents in AZ31 magnesium alloy. These steps include laser microcutting with a Q-switched fibre laser for the generation of the stent mesh and subsequent chemical etching for the cleaning of kerf and surface finish. Specifically, for the laser microcutting step, inert and reactive gas cutting conditions were compared. The effect of chemical etching on the reduction in material thickness, as well as on spatter removal, was also evaluated. Prototype stents were produced, and the material composition and surface quality were characterised. The potentialities of combining nanosecond laser microcutting and chemical etching are shown and discussed.

  3. rhoCentralRfFoam: An OpenFOAM solver for high speed chemically active flows - Simulation of planar detonations -

    Science.gov (United States)

    Gutiérrez Marcantoni, L. F.; Tamagno, J.; Elaskar, S.

    2017-10-01

    A new solver developed within the framework of OpenFOAM 2.3.0, called rhoCentralRfFoam which can be interpreted like an evolution of rhoCentralFoam, is presented. Its use, performing numerical simulations on initiation and propagation of planar detonation waves in combustible mixtures H2-Air and H2-O2-Ar, is described. Unsteady one dimensional (1D) Euler equations coupled with sources to take into account chemical activity, are numerically solved using the Kurganov, Noelle and Petrova second order scheme in a domain discretized with finite volumes. The computational code can work with any number of species and its corresponding reactions, but here it was tested with 13 chemically active species (one species inert), and 33 elementary reactions. A gaseous igniter which acts like a shock-tube driver, and powerful enough to generate a strong shock capable of triggering exothermic chemical reactions in fuel mixtures, is used to start planar detonations. The following main aspects of planar detonations are here, treated: induction time of combustible mixtures cited above and required mesh resolutions; convergence of overdriven detonations to Chapman-Jouguet states; detonation structure (ZND model); and the use of reflected shocks to determine induction times experimentally. The rhoCentralRfFoam code was verified comparing numerical results and it was validated, through analytical results and experimental data.

  4. Scratch, wear and corrosion resistant organic inorganic hybrid materials for metals protection and barrier

    International Nuclear Information System (INIS)

    Barletta, M.; Gisario, A.; Puopolo, M.; Vesco, S.

    2015-01-01

    Highlights: • Polysiloxane coatings as protective barriers to delay erosion/corrosion of Fe 430 B metal substrates. • Methyl groups feature a very small steric hindrance and confer ductility to the Si–O–Si backbone. • Phenyl groups feature a larger steric hindrance, but they ensure stability and high chemical inertness. • Remarkable adhesion to the substrate, good scratch resistance and high wear endurance. • Innovative ways to design of long lasting protective barriers against corrosion and aggressive chemicals. - Abstract: Polysiloxanes are widely used as protective barriers to delay erosion/corrosion and increase chemical inertness of metal substrates. In the present work, a high molecular weight methyl phenyl polysiloxane resin was designed to manufacture a protective coating for Fe 430 B structural steel. Methyl groups feature very small steric hindrance and confer ductility to the Si–O–Si backbone of the organic inorganic hybrid resin, thus allowing the achievement of high thickness. Phenyl groups feature larger steric hindrance, but they ensure stability and high chemical inertness. Visual appearance and morphology of the coatings were studied by field emission scanning electron microscopy and contact gauge surface profilometry. Micro-mechanical response of the coatings was analyzed by instrumented progressive load scratch, while wear resistance by dry sliding linear reciprocating tribological tests. Lastly, chemical inertness and corrosion endurance of the coatings were evaluated by linear sweep voltammetry and chronoamperometry in aggressive acid environment. The resulting resins yielded protective materials, which feature remarkable adhesion to the substrate, good scratch resistance and high wear endurance, thus laying the foundations to manufacture long lasting protective barriers against corrosion and, more in general, against aggressive chemicals

  5. Multiple inert gas elimination technique by micropore membrane inlet mass spectrometry--a comparison with reference gas chromatography.

    Science.gov (United States)

    Kretzschmar, Moritz; Schilling, Thomas; Vogt, Andreas; Rothen, Hans Ulrich; Borges, João Batista; Hachenberg, Thomas; Larsson, Anders; Baumgardner, James E; Hedenstierna, Göran

    2013-10-15

    The mismatching of alveolar ventilation and perfusion (VA/Q) is the major determinant of impaired gas exchange. The gold standard for measuring VA/Q distributions is based on measurements of the elimination and retention of infused inert gases. Conventional multiple inert gas elimination technique (MIGET) uses gas chromatography (GC) to measure the inert gas partial pressures, which requires tonometry of blood samples with a gas that can then be injected into the chromatograph. The method is laborious and requires meticulous care. A new technique based on micropore membrane inlet mass spectrometry (MMIMS) facilitates the handling of blood and gas samples and provides nearly real-time analysis. In this study we compared MIGET by GC and MMIMS in 10 piglets: 1) 3 with healthy lungs; 2) 4 with oleic acid injury; and 3) 3 with isolated left lower lobe ventilation. The different protocols ensured a large range of normal and abnormal VA/Q distributions. Eight inert gases (SF6, krypton, ethane, cyclopropane, desflurane, enflurane, diethyl ether, and acetone) were infused; six of these gases were measured with MMIMS, and six were measured with GC. We found close agreement of retention and excretion of the gases and the constructed VA/Q distributions between GC and MMIMS, and predicted PaO2 from both methods compared well with measured PaO2. VA/Q by GC produced more widely dispersed modes than MMIMS, explained in part by differences in the algorithms used to calculate VA/Q distributions. In conclusion, MMIMS enables faster measurement of VA/Q, is less demanding than GC, and produces comparable results.

  6. Nuclear activated cw chemical laser

    International Nuclear Information System (INIS)

    Roberts, T.G.

    1982-01-01

    A cw chemical laser which uses processed radioactive waste to produce active atoms from a chemically inactive gas before being mixed with another molecule such as hydrogen or deuterium is disclosed. This laser uses no toxic or corrosive fuels and does not require any electrical or other type of auxiliary power supply. The energy released by the radioactive material is used to produce the active atoms such as fluorine. This is accomplished by using the radiation products from processed radioactive waste to dissociate the inert gas in the plenum of the laser. The radioactive material is held in the passageway walls of a device similar to a heat exchanger. The exchanger device may be located in the gas generator section of a chemical laser. The inactive gas is passed through the exchanger device and while passing through it the radiation from the radioactive material dissociates the gas, producing a concentration of free active atoms. This active atom generator then feeds the nozzle bank or mixing section of a laser to produce a lasing action

  7. Separation of Nuclear Fuel Surrogates from Silicon Carbide Inert Matrix

    International Nuclear Information System (INIS)

    Baney, Ronald

    2008-01-01

    The objective of this project has been to identify a process for separating transuranic species from silicon carbide (SiC). Silicon carbide has become one of the prime candidates for the matrix in inert matrix fuels, (IMF) being designed to reduce plutonium inventories and the long half-lives actinides through transmutation since complete reaction is not practical it become necessary to separate the non-transmuted materials from the silicon carbide matrix for ultimate reprocessing. This work reports a method for that required process

  8. Triheterometallic Lanthanide Complexes Prepared from Kinetically Inert Lanthanide Building Blocks

    DEFF Research Database (Denmark)

    Sørensen, Thomas Just; Tropiano, Manuel; Kenwright, Alan M.

    2017-01-01

    Three molecular structures, each containing three different lanthanide(III) centres, have been prepared by coupling three kinetically inert lanthanide(III) complexes in an Ugi reaction. These 2 kDa molecules were purified by dialysis and characterised by NMR and luminescence techniques. The photo...... and lanthanide(III) centres in these molecules inhibits the efficient sensitisation of europium. We conclude that the intramolecular collisions required for efficient Dexter energy transfer from the sensitiser to the lanthanide(III) centre can be prevented by steric congestion....

  9. High-throughput screening of chemicals as functional ...

    Science.gov (United States)

    Identifying chemicals that provide a specific function within a product, yet have minimal impact on the human body or environment, is the goal of most formulation chemists and engineers practicing green chemistry. We present a methodology to identify potential chemical functional substitutes from large libraries of chemicals using machine learning based models. We collect and analyze publicly available information on the function of chemicals in consumer products or industrial processes to identify a suite of harmonized function categories suitable for modeling. We use structural and physicochemical descriptors for these chemicals to build 41 quantitative structure–use relationship (QSUR) models for harmonized function categories using random forest classification. We apply these models to screen a library of nearly 6400 chemicals with available structure information for potential functional substitutes. Using our Functional Use database (FUse), we could identify uses for 3121 chemicals; 4412 predicted functional uses had a probability of 80% or greater. We demonstrate the potential application of the models to high-throughput (HT) screening for “candidate alternatives” by merging the valid functional substitute classifications with hazard metrics developed from HT screening assays for bioactivity. A descriptor set could be obtained for 6356 Tox21 chemicals that have undergone a battery of HT in vitro bioactivity screening assays. By applying QSURs, we wer

  10. Formation of Load Parameters of Destroyed Massife in Explosion of Multicharge Composition with Separation of its Parts by Profile Inert Interval

    Science.gov (United States)

    Paramonov, G. P.; Mysin, A. V.; Babkin, R. S.

    2017-10-01

    The paper introduces construction of multicharge composition with separation of parts by the profile inert interval. On the basis of the previous researches, the pulse-forming process at explosion of the borehole multicharge taking into account the offered design is considered. The physical model for definition of reflected wavelet taking into account an increment of radius of cross section of a charging cavity and the expiration of detonation products is offered. A technique is developed for numerical modeling of gas-dynamic processes in a borehole with a change in the axial channel of a profile inert interval caused by a high-temperature flow of gaseous products of an explosion. The authors obtained the dependence of the change in mean pressure on the borehole wall on time for each of the parts of the multicharge. To blast a series of charges of the proposed design, taking into account optimization of the stress fields of neighboring charges, the delay interval is determined for a short-delayed explosion.

  11. Electrolytic 99TcO4- reduction at inert electrodes

    International Nuclear Information System (INIS)

    Kremer, C.; Gambino, D.; Leon, A.; Kremer, E.

    1990-01-01

    Electrolytic pertechnetate reduction at inert electrodes was studied as an alternative procedure for synthesizing Tc complexes. Pertechnetate reduction was carried out in aqueous media using different aminated ligands (en, dien, trien and 1,3-dap) forming [TcO 2 (amine) 2 ] + type complexes. Simultaneously with synthesis of the desired Tc complex, TcO 2 was electrodeposited onto the cathode. Conversion of TcO 4 - to Tc complex and TcO 2 was studied as a function of several variables (kind and concentration of supporting electrolyte, ligand concentration, pH, current and electrolysis time). (author) 9 refs.; 6 figs.; 1 tab

  12. Impact of airway gas exchange on the multiple inert gas elimination technique: theory.

    Science.gov (United States)

    Anderson, Joseph C; Hlastala, Michael P

    2010-03-01

    The multiple inert gas elimination technique (MIGET) provides a method for estimating alveolar gas exchange efficiency. Six soluble inert gases are infused into a peripheral vein. Measurements of these gases in breath, arterial blood, and venous blood are interpreted using a mathematical model of alveolar gas exchange (MIGET model) that neglects airway gas exchange. A mathematical model describing airway and alveolar gas exchange predicts that two of these gases, ether and acetone, exchange primarily within the airways. To determine the effect of airway gas exchange on the MIGET, we selected two additional gases, toluene and m-dichlorobenzene, that have the same blood solubility as ether and acetone and minimize airway gas exchange via their low water solubility. The airway-alveolar gas exchange model simulated the exchange of toluene, m-dichlorobenzene, and the six MIGET gases under multiple conditions of alveolar ventilation-to-perfusion, VA/Q, heterogeneity. We increased the importance of airway gas exchange by changing bronchial blood flow, Qbr. From these simulations, we calculated the excretion and retention of the eight inert gases and divided the results into two groups: (1) the standard MIGET gases which included acetone and ether and (2) the modified MIGET gases which included toluene and m-dichlorobenzene. The MIGET mathematical model predicted distributions of ventilation and perfusion for each grouping of gases and multiple perturbations of VA/Q and Qbr. Using the modified MIGET gases, MIGET predicted a smaller dead space fraction, greater mean VA, greater log(SDVA), and more closely matched the imposed VA distribution than that using the standard MIGET gases. Perfusion distributions were relatively unaffected.

  13. High temperature slagging incinerator for alpha contaminated wastes

    International Nuclear Information System (INIS)

    Van de Voorde, N.

    1985-01-01

    This report describes the experiences collected by the treatment of plutonium-contaminated wastes, in the High Temperature Slagging Incinerator at the C.E.N./S.C.K. at Mol, with the support of the Commission of the European Communities. The major objective of the exercise is to demonstrate the operability of this facility for the treatment of mixed transuranic (TRU) and beta-gamma solid waste material. The process will substantially reduce the TRU waste volume by burning the combustibles and converting the non-combustibles into a chemically inert and physically stable basalt-like slag product, suitable for safe transport and final disposal. (Auth.)

  14. Water fog inerting of hydrogen-air mixtures

    International Nuclear Information System (INIS)

    Zalosh, R.G.; Bajpai, S.N.

    1982-01-01

    Laboratory tests have been conducted to determine the effects of water fog density, droplet diameter and temperature on the lower flammable limit (LFL) of hydrogen-air-steam mixtures. Five different fog nozzles were used to generate dense fogs with volume mean drop diameters ranging from 20 micro-meters to 115 micro-meters. At 20 0 C, these nozzles marginally raised the hydrogen LFL from 4.0 vol.% hydrogen to typically 4.8%, with one exceptional nozzle producing an LFL of 7.2%. At 50 0 C, the LFL in the presence of dense fog ranged from 5.0 to 7.9%, while at 70 0 C, the range was 5.9 to 8.5%. Fog densities required to achieve a given level of partial inerting increased with approximately the second power of average drop diameter, as predicted by a theoretical flame quenching analysis

  15. Measurement of cross-sections for step-bystep excitation of inert gas atoms from metastable states by electron collisions

    International Nuclear Information System (INIS)

    Mityureva, A.A.; Penkin, N.P.; Smirnov, V.V.

    1989-01-01

    Excitation of argon atoms by electron collisions from metastable (MS) to high-lying states of inert gases (the so-called step-by-step excitation) is investigated. Formation of MS atoms m and their further step-by-step excitation up to k level is carried out by an electron beam with energy from 1 up to 40 eV. Time distribution of forming metastable and step-by-step electron collisions is used. The method used permits to measure the functions of step-by-step excitation and the absolute values of cross sections. Absolute values of cross-sections and functions of step-by-step excitation of some lines and argon levels are obtained

  16. High-throughput screening of chemical effects on ...

    Science.gov (United States)

    Disruption of steroidogenesis by environmental chemicals can result in altered hormone levels causing adverse reproductive and developmental effects. A high-throughput assay using H295R human adrenocortical carcinoma cells was used to evaluate the effect of 2,060 chemical samples on steroidogenesis via HPLC-MS/MS quantification of 10 steroid hormones, including progestagens, glucocorticoids, androgens, and estrogens. The study employed a three stage screening strategy. The first stage established the maximum tolerated concentration (MTC; >70% viability) per sample. The second stage quantified changes in hormone levels at the MTC while the third stage performed concentration-response (CR) on a subset of samples. At all stages, cells were pre-stimulated with 10 µM forskolin for 48 h to induce steroidogenesis followed by chemical treatment for 48 h. Of the 2,060 chemical samples evaluated, 524 samples were selected for six-point CR screening, based in part on significantly altering at least 4 hormones at the MTC. CR screening identified 232 chemical samples with concentration-dependent effects on 17β-estradiol and/or testosterone, with 411 chemical samples showing an effect on at least one hormone across the steroidogenesis pathway. Clustering of the concentration-dependent chemical-mediated steroid hormone effects grouped chemical samples into five distinct profiles generally representing putative mechanisms of action, including CYP17A1 and HSD3B inhibition. A d

  17. Report on the treatability study for inerting small quantities of radioactive explosives and explosive components

    International Nuclear Information System (INIS)

    Loyola, V.M.; Reber, S.D.

    1996-02-01

    As a result of Sandia's radiation hardening testing on a variety of its explosive components, radioactive waste streams were generated and have to be disposed of as radioactive waste. Due to the combined hazards of explosives and radioactivity, Sandia's Radioactive and Mixed Waste Management organization did not have a mechanism for disposal of these waste streams. This report documents the study done to provide a method for the removal of the explosive hazard from those waste streams. The report includes the design of the equipment used, procedures followed, results from waste stream analog tests and the results from the actual explosive inerting tests on radioactive samples. As a result of the inerting treatment, the waste streams were rendered non-explosive and, thus, manageable through normal radioactive waste disposal channels

  18. Identification of market bags composition for biodegradable and oxo-biodegradable samples through thermal analysis in inert and oxidizer atmosphere

    International Nuclear Information System (INIS)

    Finzi-Quintao, Cristiane M.; Novack, Katia M.

    2015-01-01

    Plastic films used to make market bags are based on polymers such as polyethylene, polystyrene and polypropylene, these materials require a long time to degrade in the environment. The alternative technologies of polymers have been developed to reduce the degradation time and the impact on the environment caused by the conventional materials, using pro-degrading additives or by the development biodegradable polymers. In Brazil, the laws of some municipalities require the use of biodegradable material in the production of market bags but the absence of specific surveillance policies makes its chemical composition unknown. In this paper, we analyzed 7 samples that was obtained from a a trading company and commercial market of Belo Horizonte . The samples were characterized by TGA / DTA , XRF , FTIR and MEV which allowed the identification and evaluation of the thermal behavior of the material in inert and oxidizing atmosphere. (author)

  19. Purification process of natural graphite as anode for Li-ion batteries: chemical versus thermal

    Science.gov (United States)

    Zaghib, K.; Song, X.; Guerfi, A.; Rioux, R.; Kinoshita, K.

    The intercalation of Li ions in natural graphite that was purified by chemical and thermal processes was investigated. A new chemical process was developed that involved a mixed aqueous solution containing 30% H 2SO 4 and 30% NH xF y heated to 90 °C. The results of this process are compared to those obtained by heating the natural graphite from 1500 to 2400 °C in an inert environment (thermal process). The first-cycle coulombic efficiency of the purified natural graphite obtained by the chemical process is 91 and 84% after the thermal process at 2400 °C. Grinding the natural graphite before or after purification had no significant effect on electrochemical performance at low currents. However, grinding to a very small particle size before purification permitted optimization of the size distribution of the particles, which gives rise to a more homogenous electrode. The impurities in the graphite play a role as microabrasion agents during grinding which enhances its hardness and improves its mechanical properties. Grinding also modifies the particle morphology from a 2- to a 3-D structure (similar in shape to a potato). This potato-shaped natural graphite shows high reversible capacity at high current densities (about 90% at 1 C rate). Our analysis suggests that thermal processing is considerably more expensive than the chemical process to obtain purified natural graphite.

  20. Environmental impact of industrial sludge stabilization/solidification products: chemical or ecotoxicological hazard evaluation?

    Science.gov (United States)

    Silva, Marcos A R; Testolin, Renan C; Godinho-Castro, Alcione P; Corrêa, Albertina X R; Radetski, Claudemir M

    2011-09-15

    Nowadays, the classification of industrial solid wastes is not based on risk analysis, thus the aim of this study was to compare the toxicity classifications based on the chemical and ecotoxicological characterization of four industrial sludges submitted to a two-step stabilization/solidification (S/S) processes. To classify S/S products as hazardous or non-hazardous, values cited in Brazilian chemical waste regulations were adopted and compared to the results obtained with a battery of biotests (bacteria, alga and daphnids) which were carried out with soluble and leaching fractions. In some cases the hazardous potential of industrial sludge was underestimated, since the S/S products obtained from the metal-mechanics and automotive sludges were chemically classified as non-hazardous (but non-inert) when the ecotoxicity tests showed toxicity values for leaching and soluble fractions. In other cases, the environmental impact was overestimated, since the S/S products of the textile sludges were chemically classified as non-inert (but non-hazardous) while ecotoxicity tests did not reveal any effects on bacteria, daphnids and algae. From the results of the chemical and ecotoxicological analyses we concluded that: (i) current regulations related to solid waste classification based on leachability and solubility tests do not ensure reliable results with respect to environmental protection; (ii) the two-step process was very effective in terms of metal immobilization, even at higher metal-concentrations. Considering that S/S products will be subject to environmental conditions, it is of great interest to test the ecotoxicity potential of the contaminants release from these products with a view to avoiding environmental impact given the unreliability of ecotoxicological estimations originating from chemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Development of high power chemical oxygen lodine laser

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Choi, Y. D.; Chung, C. M.; Kim, M. S.; Baik, S. H.; Kwon, S. O.; Park, S. K.; Kim, T. S

    2001-10-01

    This project is directed to construct 10kW Chemical Oxygen Iodine Laser (COIL) for decommissioning of old nuclear facilities, and to get the key technology that can be used for the development of high energy laser weapon. COIL is possible up to MW class in proportion to the amount of chemical reaction. For this reason, high energy laser weapon including Airborne Laser (ABL) and Airborne Tactical Laser (ATL) has been developed as a military use in USA. Recently, many research group have been doing a development study of COIL for nuclear and industrial use in material processing such as cutting and decommissioning by combining laser beam delivery through optical fiber. The Chemical Oxygen Iodine Laser of 6 kW output power has been developed in this project. The main technologies of chemical reaction and supersonic fluid control were developed. This technology can be applied for construction of 10 kW laser system. This laser can be used for old nuclear facilities and heavy industry by combining laser beam delivery through optical fiber. The development of High Energy Laser (HEL) weapon is necessary as a military use, and we conclude that Airborne Tactical Laser should be developed in our country.

  2. Chemical Stability Investigations of Polyisobutylene as New Binder for Application in Lithium Air-Batteries

    International Nuclear Information System (INIS)

    Heine, Jennifer; Rodehorst, Uta; Badillo, Juan Pablo; Winter, Martin; Bieker, Peter

    2015-01-01

    ABSTRACT: The side reactions of LiO 2 , Li 2 O 2 and Li 2 O, formed during the discharge process at the cathode/electrolyte interphase, are still a main challenge of lithium-air batteries. During these reactions, polyvinylidene difluoride (PVdF), as the commonly used cathode binder material, is decomposing, leading to a shorter lifetime of the battery. In this paper, we introduced and investigated polyisobutylene (PIB), a chemically and electrochemically inert polymeric material, to substitute PVdF as binder for lithium-air batteries. Results obtained by X-ray diffraction and spectroscopic methods showed, that PIB is far more stable in the presence of O 2 − , O 2 2− as well as O 2− species compared to PVdF. This distinct inertness makes PIB a promising binder for lithium-air batteries

  3. The inert doublet model: a new archetype of WIMP dark matter?

    International Nuclear Information System (INIS)

    Tytgat, M Hg

    2008-01-01

    The Inert Doublet Model (IDM) is a two doublet extension of the Higgs-Brout-Englert sector of the Standard Model with a Z2 symmetry in order to prevent FCNC. If the Z2 symmetry is not spontaneously broken, the lightest neutral extra scalar is a dark matter candidate. We briefly review the phenomenology of the model, emphasizing its relevance for the issue of Electroweak Symmetry Breaking (EWSB) and the prospects for detection of dark matter

  4. Bomb radiocarbon in metabolically inert tissues from terrestrial and marine mammals

    International Nuclear Information System (INIS)

    Bada, J.L.; Vrolijk, C.D.; Brown, S.; Druffel, E.R.M.; Hedges, R.E.M.

    1987-01-01

    We report here radiocarbon measurements of monkey eye lens nucleus proteins and a narwhal tusk, biological tissues which have sampled the bomb radiocarbon signal in different ways. The results confirm the metabolic inertness of eye lens nucleus proteins and demonstrate the feasibility of measuring radiocarbon in small samples of biological tissue using accelerator mass spectrometry (AMS). The narwhal tusk provides a unique record of the radiocarbon activity in Arctic Ocean waters over most of the 20th century

  5. A method for determining optimum phasing of a multiphase propulsion system for a single-stage vehicle with linearized inert weight

    Science.gov (United States)

    Martin, J. A.

    1974-01-01

    A general analytical treatment is presented of a single-stage vehicle with multiple propulsion phases. A closed-form solution for the cost and for the performance and a derivation of the optimal phasing of the propulsion are included. Linearized variations in the inert weight elements are included, and the function to be minimized can be selected. The derivation of optimal phasing results in a set of nonlinear algebraic equations for optimal fuel volumes, for which a solution method is outlined. Three specific example cases are analyzed: minimum gross lift-off weight, minimum inert weight, and a minimized general function for a two-phase vehicle. The results for the two-phase vehicle are applied to the dual-fuel rocket. Comparisons with single-fuel vehicles indicate that dual-fuel vehicles can have lower inert weight either by development of a dual-fuel engine or by parallel burning of separate engines from lift-off.

  6. Anisotropic silica mesostructures for DNA encapsulation

    Indian Academy of Sciences (India)

    The encapsulation of biomolecules in inert meso or nanostructures is an important step towards controlling drug delivery agents. Mesoporous silica nanoparticles (MSN) are of immense importance owing to their high surface area, large pore size, uniform particle size and chemical inertness. Reverse micellar method with ...

  7. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    International Nuclear Information System (INIS)

    MM Hall

    2006-01-01

    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing

  8. A comparative evaluation of microstructural and mechanical behavior of fiber laser beam and tungsten inert gas dissimilar ultra high strength steel welds

    Directory of Open Access Journals (Sweden)

    Jaiteerth R. Joshi

    2016-12-01

    Full Text Available The influence of different welding processes on the mechanical properties and the corresponding variation in the microstructural features have been investigated for the dissimilar weldments of 18% Ni maraging steel 250 and AISI 4130 steel. The weld joints are realized through two different fusion welding processes, tungsten inert arc welding (TIG and laser beam welding (LBW, in this study. The dissimilar steel welds were characterized through optical microstructures, microhardness survey across the weldment and evaluation of tensile properties. The fiber laser beam welds have demonstrated superior mechanical properties and reduced heat affected zone as compared to the TIG weldments.

  9. Investigation of hydrogen generation in a three reactor chemical looping reforming process

    International Nuclear Information System (INIS)

    Khan, Mohammed N.; Shamim, Tariq

    2016-01-01

    Highlights: • Three-reactor based chemical looping reforming system for hydrogen production. • Investigation of operating parameters using a system-level model. • Optimum operating conditions for hydrogen production are identified. • Different operating parameters affect the reactor temperatures differently. - Abstract: Chemical looping reforming (CLR) is a relatively new method to produce hydrogen (H_2) and is also used as an energy conversion method for solid, liquid or gaseous fuels. There are various advantages of this method such as inherent carbon dioxide (CO_2) capture, minimal NOx emissions and the H_2 production. In this process, there is no direct contact between the fuel and oxidizer. This method utilizes oxygen from an oxygen carrier which may be a transition metal. The idea is to split the combustion process into three separate sub-processes by employing three separate reactors: air reactor where the oxygen carrier is oxidized by air, fuel reactor where natural gas is oxidized to produce a stream of CO_2 and H_2O and steam reactor where the steam is reduced to produce H_2. In this study, a thermodynamic model with iron oxides as oxygen carrier has been developed using Aspen Plus by employing conservation of mass and energy for all the components of the CLR system. The developed model was employed to investigate the effect of various operating parameters such as mass flow rates of air, fuel, steam and oxygen carrier and fraction of inert material on H_2 and CO_2 production and key reactor temperatures. The results show that the H_2 production increases with the increase in air, fuel and steam flow rates up to a certain limit and stays constant for higher flow rates. The CO_2 production follows a similar trend. Similarly, the H_2 production also increases with the increase in oxide flow rate and fraction of inert material up to a particular value, but then decrease for higher oxide flow rates and inert fractions. Reactor temperatures were also

  10. Substances inertes et plantes à effet insecticide utilisées dans la ...

    African Journals Online (AJOL)

    Les insecticides naturels tels que les plantes à effet insecticide et les substances inertes (sable, cendre, terres à diatomées,…) méritent d'être valorisées afin de réduire l'utilisation des insecticides chimiques et protéger l'environnement. Ce travail basé sur une revue documentaire fouillée et actualisée vise à faire la genèse ...

  11. Nb-TiO{sub 2}/polymer hybrid solar cells with photovoltaic response under inert atmosphere conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lira-Cantu, Monica; Khoda Siddiki, Mahbube; Munoz-Rojas, David; Amade, Roger [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Gonzalez-Pech, Natalia I. [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Instituto Tecnologico y de Estudios Superiores de Monterrey (ITESM), Ave. Eugenio Garza Sada, 64640 Monterrey, N.L. (Mexico)

    2010-07-15

    Hybrid Solar Cells (HSC) applying Nb-TiO{sub 2} in direct contact with a conducting organic polymer, MEH-PPV, show higher stability than the bare TiO{sub 2}-based HSC when analyzed under inert atmosphere conditions. IPCE analyses revealed that inert atmospheres affect directly the semiconductor oxide in the first stages of the analyses but photovoltaic performance stabilizes after several hours. A 20 wt% Nb-doped TiO{sub 2} presented the highest stability and photovoltaic properties. The behavior has been attributed to the solubility limit of Nb within the TiO{sub 2} beyond 20 wt% doping level where the co-existence of NbO{sub 2} is observed. The HSCs were analyzed under controlled N{sub 2} atmosphere and 1000 W/m{sup 2} (AM 1.5) irradiation. (author)

  12. Investigation of materials for inert electrodes in aluminum electrodeposition cells

    Energy Technology Data Exchange (ETDEWEB)

    Haggerty, J. S.; Sadoway, D. R.

    1987-09-14

    Work was divided into major efforts. The first was the growth and characterization of specimens; the second was Hall cell performance testing. Cathode and anode materials were the subject of investigation. Preparation of specimens included growth of single crystals and synthesis of ultra high purity powders. Special attention was paid to ferrites as they were considered to be the most promising anode materials. Ferrite anode corrosion rates were studied and the electrical conductivities of a set of copper-manganese ferrites were measured. Float Zone, Pendant Drop Cryolite Experiments were undertaken because unsatisfactory choices of candidate materials were being made on the basis of a flawed set of selection criteria applied to an incomplete and sometimes inaccurate data base. This experiment was then constructed to determine whether the apparatus used for float zone crystal growth could be adapted to make a variety of important based melts and their interactions with candidate inert anode materials. The third major topic was Non Consumable Anode (Data Base, Candidate Compositions), driven by our perception that the basis for prior selection of candidate materials was inadequate. Results are presented. 162 refs., 39 figs., 18 tabs.

  13. The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition

    International Nuclear Information System (INIS)

    Tulenko, J.S.; Wang, J.; Acosta, C.

    2004-01-01

    The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being a basic fuel material in gas cooled reactors

  14. Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices

    KAUST Repository

    Ibrahim, Youssef H.

    2013-01-01

    . The processing requirements for laser devices and ridge waveguides are stringent as compared to LEDs and other electronic devices. Due to the strong bonding and chemically inert nature of GaN, dry etching becomes a critical fabrication step. The surface

  15. The effect on lactic fermentation of concentrating inert material with immobilised cells in a calcium alginate biocatalyser

    Directory of Open Access Journals (Sweden)

    Juan Carlos Serrato

    2005-05-01

    Full Text Available Colombia is one of the world’s main sugarcane cultivating countries but it has not diversified its fermentation industry; a few fermentation industries produce alcohol and yeasts. Lactic acid and its derivatives then become alternatives providing added value to the sugar produced, thus benefiting the regions producing the sugar.This work evaluated the kinetics of lactic acid production using immobilised cells in calcium alginate at different concentrations of inert material. Lactobacillus delbrueckiI was the microorganism used and fermentation broth mainly consisted of sucrose and yeast exact. CSTR reactors were used without pH control. The results suggested that 2% to 3% inert material in the biocatalyst increased cellular retention and diffusiveness, leading to improved conversion and reaction rate.

  16. Non-equilibrium effects in high temperature chemical reactions

    Science.gov (United States)

    Johnson, Richard E.

    1987-01-01

    Reaction rate data were collected for chemical reactions occurring at high temperatures during reentry of space vehicles. The principle of detailed balancing is used in modeling kinetics of chemical reactions at high temperatures. Although this principle does not hold for certain transient or incubation times in the initial phase of the reaction, it does seem to be valid for the rates of internal energy transitions that occur within molecules and atoms. That is, for every rate of transition within the internal energy states of atoms or molecules, there is an inverse rate that is related through an equilibrium expression involving the energy difference of the transition.

  17. Transformation of highly toxic chemicals factory for Fuqing nuclear power plant

    International Nuclear Information System (INIS)

    Wang Hongkai; Gao Yuan; Li Hua

    2014-01-01

    For the iodine adsorption tests of current M310 nuclear power plant, dimethyl sulfate is one of highly toxic chemical of national strict standard management, and the nation make strict control over toxic chemicals procurement, transportation, storage, management requirements. Since the appropriate toxic chemicals storage place was not considered in the design of M310 nuclear power plant, Fuqing nuclear power sites for storage of dimethyl sulfate implement technical transformation to meet and regulate the storage requirements for highly toxic chemical. This will lay the foundation for carrying out smoothly the relevant tests of nuclear power plant, and provide the reference for the use and construction of toxic chemicals reactor in the same type nuclear power plant. (authors)

  18. A technique for measuring hydrogen and water in inert gases and the hydrogen concentration in liquid sodium

    International Nuclear Information System (INIS)

    Smith, C.A.

    1978-04-01

    A method is described of measuring the hydrogen and water content of an inert gas. It is based upon the use of an electrochemical oxygen cell and has a high sensitivity at low hydrogen and water levels. The following possible applications of the method are described together with supporting experimental measurements: improving the sensitivity and range of the present PFR secondary circuit hydrogen detection instruments; the measurement of hydrogen diffusion coefficients in steels; the measurement of waterside corrosion rates of boiler steels; on-line monitoring of waterside boiler corrosion. Attention is given to the characteristics of diffusion barriers in relation to the first and last of these. (author)

  19. Oxidation and reduction behaviors of a prototypic MgO-PuO{sub 2-x} inert matrix fuel

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Shuhei, E-mail: miwa.shuhei@jaea.go.jp; Osaka, Masahiko

    2017-04-15

    Oxidation and reduction behaviors of prototypic MgO-based inert matrix fuels (IMFs) containing PuO{sub 2-x} were experimentally investigated by means of thermogravimetry. The oxidation and reduction kinetics of the MgO-PuO{sub 2-x} specimen were determined. The oxidation and reduction rates of the MgO-PuO{sub 2-x} were found to be low compared with those of PuO{sub 2-x}. It is note that the changes in O/Pu ratios of MgO-PuO{sub 2-x} from stoichiometry were smaller than those of PuO{sub 2-x} at high oxygen partial pressure.

  20. Modelling the transient behaviour of pulsed current tungsten-inert-gas weldpools

    Science.gov (United States)

    Wu, C. S.; Zheng, W.; Wu, L.

    1999-01-01

    A three-dimensional model is established to simulate the pulsed current tungsten-inert-gas (TIG) welding process. The goal is to analyse the cyclic variation of fluid flow and heat transfer in weldpools under periodic arc heat input. To this end, an algorithm, which is capable of handling the transience, nonlinearity, multiphase and strong coupling encountered in this work, is developed. The numerical simulations demonstrate the transient behaviour of weldpools under pulsed current. Experimental data are compared with numerical results to show the effectiveness of the developed model.

  1. Corrosion characterisation of laser beam and tungsten inert gas weldment of nickel base alloys: Micro-cell technique

    International Nuclear Information System (INIS)

    Abraham, Geogy J.; Kain, V.; Dey, G.K.; Raja, V.S.

    2015-01-01

    Highlights: • Grain matrix showed better corrosion resistance than grain boundary. • Microcell studies showed distinct corrosion behaviour of individual regions of weldment. • TIG welding resulted in increased stable anodic current density on weld fusion zone. • LB welding resulted in high stable anodic current density for heat affected zone. - Abstract: The electrochemical studies using micro-cell technique gave new understanding of electrochemical behaviour of nickel base alloys in solution annealed and welded conditions. The welding simulated regions depicted varied micro structural features. In case of tungsten inert gas (TIG) weldments, the weld fusion zone (WFZ) showed least corrosion resistance among all other regions. For laser beam (LB) weldments it was the heat-affected zone (HAZ) that showed comparatively high stable anodic current density. The high heat input of TIG welding resulted in slower heat dissipation hence increased carbide precipitation and segregation in WFZ resulting in high stable anodic current density

  2. Heat and mass transfer in turbulent chemically nonequilibrium flow in the tube with boundary second kind conditions. The section with the stabilized heat and mass transfer

    International Nuclear Information System (INIS)

    Kritsuk, E.L.; Mishina, L.V.; Shegidevich, L.N.

    1986-01-01

    The hydrodynamically stabilized chemically nonequilibrium turbulent flow in a tube with the inert impermeable surface and constant specific heat flow on the wall is considered. The reversible homogeneous reaction of nitrogen dioxide dissociation 2NO 2 ↔ 2NO+O 2 takes place in the flow. Chemically equilibrium flow with homogeneous profile of temperature and concentration arrives into the channel inlet. After application of simplifying assumptions, the expressions for characteristics of heat and mass transfer have been written down, which are valid in the whole range of the flow parameter variation from frozen up to chemically equilibrium flow. An integral transformation method is suggested for a radial coordinate which allows a wall region to be extended, thereby essentially extending the step of integration. A solution in quadratures has been obtained for the heat and mass transfer problem in an inert fluid flow for the developed process section. The elimination method has been employed to solve the boundary-value second-kind problem for the function governing heat and mass transfer in a chemically nonequilibrium turbulent flow over the developed heat and mass transfer section. The results of calculations are presented

  3. Mobility of supercooled liquid toluene, ethylbenzene, and benzene near their glass transition temperatures investigated using inert gas permeation.

    Science.gov (United States)

    May, R Alan; Smith, R Scott; Kay, Bruce D

    2013-11-21

    We investigate the mobility of supercooled liquid toluene, ethylbenzene, and benzene near their respective glass transition temperatures (Tg). The permeation rate of Ar, Kr, and Xe through the supercooled liquid created when initially amorphous overlayers are heated above their glass transition temperature is used to determine the diffusivity. Amorphous benzene crystallizes at temperatures well below its Tg, and as a result, the inert gas underlayer remains trapped until the onset of benzene desorption. In contrast, for toluene and ethylbenzene the onset of inert gas permeation is observed at temperatues near Tg. The inert gas desorption peak temperature as a function of the heating rate and overlayer thickness is used to quantify the diffusivity of supercooled liquid toluene and ethylbenzene from 115 to 135 K. In this temperature range, diffusivities are found to vary across 5 orders of magnitude (∼10(-14) to 10(-9) cm(2)/s). The diffusivity data are compared to viscosity measurements and reveal a breakdown in the Stokes-Einstein relationship at low temperatures. However, the data are well fit by the fractional Stokes-Einstein equation with an exponent of 0.66. Efforts to determine the diffusivity of a mixture of benzene and ethylbenzene are detailed, and the effect of mixing these materials on benzene crystallization is explored using infrared spectroscopy.

  4. Synthesis and chemical recycling of high polymers using C1 compounds; C1 kagobutsu ni yoru kobunshi no chemical recycle

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, T. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1997-09-01

    The paper outlined a study of the synthesis of high polymers using C1 compounds which are continuously usable chemical materials and the related compounds such as the derivatives, and also the chemical recycle. In the case of waste plastics mixed in urban refuse, effective is the chemical recycle where C1 compounds obtained by gasifying the mixed waste are used as high polymer material. For the synthesis and recycle of high polymers using C1 compounds, there are three routes: Route A (recycle via high polymer materials), Route B (recycle via C1 compounds and high polymer materials), and Route C including global-scale carbon recycle (recycle via carbon dioxide from biodegradable plastics using microorganism). Among high polymers, those that can be synthesized from C1 compounds, for example, polymethylene, polyacetal and polyketone can be chemically recycled by Route B. 30 refs., 2 figs., 1 tab.

  5. Very high efficacy electrodeless high intensity discharge lamps

    Science.gov (United States)

    Johnson, Peter D.

    1987-01-01

    An electrodeless arc lamp comprises an outer jacket hermetically sealing and thermally protecting an arc tube inside which has an upwardly convex bottom center section. The absence of chemically reactive electrode material makes it possible to use metal halides other than iodides. The tube contains chlorides, bromides or a mixture thereof of scandium and sodium in a nearly equimolar relationship in addition to mercury and an inert gas. Good color balance can be obtained at reduced reservoir temperature and with less power loss. Reduction in wall temperature makes it possible to attain longer lamp life.

  6. Exploring Cu2O/Cu cermet as a partially inert anode to produce aluminum in a sustainable way

    International Nuclear Information System (INIS)

    Feng, Li-Chao; Xie, Ning; Shao, Wen-Zhu; Zhen, Liang; Ivanov, V.V.

    2014-01-01

    Highlights: • Cu 2 O/Cu cermet was used as a candidate partially inert anode material to produce aluminum alloys. • The thermal corrosion behavior of Cu 2 O/Cu was investigated in molten salt at 960 °C. • The corrosion rate is largely governed by the geometrical structures of Cu in the prepared samples. • The corrosion rate increases with decreasing sizes and increasing filling contents of Cu phase. • The corrosion rate was 1.8–9 cm/y and the Cu contents is less than 6.2 wt.% in the produced aluminum. - Abstract: As an energy-intensive process, aluminum production by the Hall–Héroult method accounts for significant emissions of CO 2 and some toxic greenhouse gases. The utilization of an inert anode in place of a carbon anode was considered as a revolutionary technique to solve most of the current environmental problems resulting from the Hall–Héroult process. However, the critical property requirements of the inert anode materials significantly limit the application of this technology. In light of the higher demand for aluminum alloys than for pure aluminum, a partially inert anode was designed to produce aluminum alloys in a more sustainable way. Here, Cu 2 O/Cu cermet was chosen as the material of interest. The thermal corrosion behavior of Cu 2 O/Cu was investigated in Na 3 AlF 6 –CaF 2 –Al 2 O 3 electrolyte at 960 °C to elucidate the corrosion mechanisms of this type of partially inert anode for the production of aluminum or aluminum alloys. Furthermore, the effects of the geometrical structure of the Cu phase on the thermal corrosion behavior of Cu 2 O/Cu cermet in the electrolyte were investigated as well. The thermal corrosion rate was evaluated by the weight loss method and the results show that the samples prepared with branch-like Cu have higher thermal corrosion rate than those prepared with spherical Cu, and the corrosion rate increases with decreasing size and increasing filling content of Cu phase. The calculated corrosion rate

  7. Design and validation of inert homemade explosive simulants for ground penetrating radar

    Science.gov (United States)

    VanderGaast, Brian W.; McFee, John E.; Russell, Kevin L.; Faust, Anthony A.

    2015-05-01

    The Canadian Armed Forces (CAF) identified a requirement for inert simulants to act as improvised, or homemade, explosives (IEs) when training on, or evaluating, ground penetrating radar (GPR) systems commonly used in the detection of buried landmines and improvised explosive devices (IEDs). In response, Defence R and D Canada (DRDC) initiated a project to develop IE simulant formulations using commonly available inert materials. These simulants are intended to approximate the expected GPR response of common ammonium nitrate-based IEs, in particular ammonium nitrate/fuel oil (ANFO) and ammonium nitrate/aluminum (ANAl). The complex permittivity over the range of electromagnetic frequencies relevant to standard GPR systems was measured for bulk quantities of these three IEs that had been fabricated at DRDC Suffield Research Centre. Following these measurements, published literature was examined to find benign materials with both a similar complex permittivity, as well as other physical properties deemed desirable - such as low-toxicity, thermal stability, and commercial availability - in order to select candidates for subsequent simulant formulation. Suitable simulant formulations were identified for ANFO, with resulting complex permittivities measured to be within acceptable limits of target values. These IE formulations will now undergo end-user trials with CAF operators in order to confirm their utility. Investigations into ANAl simulants continues. This progress report outlines the development program, simulant design, and current validation results.

  8. NERI FINAL TECHNICAL REPORT, DE-FC07-O5ID14647. OPTIMIZATION OF OXIDE COMPOUNDS FOR ADVANCED INERT MATRIX MATERIALS

    International Nuclear Information System (INIS)

    Nino, Juan C.

    2009-01-01

    In order to reduce the current excesses of plutonium (both weapon grade and reactor grade) and other transuranium elements, a concept of inert matrix fuel (IMF) has been proposed for an uranium free transmutation of fissile actinides which excludes continuous uranium-plutonium conversion in thermal reactors and advanced systems. Magnesium oxide (MgO) is a promising candidate for inert matrix (IM) materials due to its high melting point (2827 C), high thermal conductivity (13 W/K · m at 1000 C), good neutronic properties, and irradiation stability However, MgO reacts with water and hydrates easily, which prevents it from being used in light water reactors (LWRs) as an IM. To improve the hydration resistance of MgO-based inert matrix materials, Medvedev and coworkers have recently investigated the introduction of a secondary phase that acts as a hydration barrier. An MgO-ZrO 2 composite was specifically studied and the results showed that the composite exhibited improved hydration resistance than pure MgO. However, ZrO 2 is insoluble in most acids except HF, which is undesirable for fuel reprocessing. Moreover, the thermal conductivity of ZrO 2 is low and typically less than 3 W · m -1 · K -1 at 1000 C. In search for an alternative composite strategy, Nd 2 Zr 2 O 7 , an oxide compound with pyrochlore structure, has been proposed recently as a corrosion resistant phase, and MgO-Nd 2 Zr 2 O 7 composites have been investigated as potential IM materials. An adequate thermal conductivity of 6 W · m - 1 · K -1 at 1000 C for the MgO-Nd 2 Zr 2 O 7 composite with 90 vol% MgO was recently calculated and reported. Other simulations proposed that the MgO-pyrochlore composites could exhibit higher radiation stability than previously reported. Final optimization of the composite microstructure was performed on the 70 vol% MgO-Nd 2 Zr 2 O 7 composite that burnup calculations had shown to have the closest profile to that of MOX fuel. Theoretical calculations also indicated that

  9. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

    Science.gov (United States)

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-01-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm−3, with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

  10. Atomic nitrogen encapsulated in fullerenes: realization of a chemical Faraday cage

    International Nuclear Information System (INIS)

    Lips, K.

    2000-01-01

    Fullerenes, C 60 and C 70 , are ideal containers for atomic nitrogen. We will show by electron paramagnetic resonance (EPR) experiments that nitrogen in C 60 keeps its atomic ground state configuration and resides in the center of the cage. This is the first time that atomic nitrogen is stabilized at ambient conditions. The inert shell of the fullerene protects the highly reactive nitrogen from undergoing chemical reactions with the surroundings. The fullerene cage is the chemical analogue of the Faraday cage in case of electrical fields, i.e. it shields off the chemical reactivity. As for the free nitrogen atom, the spins of the three p-electrons of nitrogen in C 60 are parallel (S = 3/2) and the atom has spherical symmetry. Due to the center position of nitrogen in C 60 , extremely sharp EPR lines are observed. This reflects the absence of a strong host-guest interaction and shows that the individuality of nitrogen in the fullerenes is preserved. Further evidence for the almost interaction-free suspension of nitrogen in the fullerene cages is provided by g-factor measurements. These investigations show that magnetic shielding of the host molecules can account for the observed differences between N rate at C 60 and N rate at C 70 . The fullerene cage can be chemically modified without destroying the endohedral complex. The chemical modifications change the symmetry of the molecule which is observed through an additional fine structure in the EPR spectrum. Influences of the modifications on the stability of N rate at C 60 will be discussed. (orig.)

  11. Chemical composition effects of methylene containing polymers on gas emission under γ-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Dannoux-Papin, A. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Dély, N. [CEA, DSM, IRAMIS, LIDYL, PCR, F-91191 Gif-sur-Yvette (France); Legand, S.; Durand, D.; Roujou, J.L.; Lamouroux, C.; Dauvois, V. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Coignet, P.; Cochin, F. [AREVA NC DOR/RDP, 1 place Jean Millier, 92084 La Défense (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); CEA, DSM, IRAMIS, LIDYL, PCR, F-91191 Gif-sur-Yvette (France)

    2014-09-01

    The presence of different chemical groups in methylene containing polymers can lead to very different behaviors under ionizing radiation. To better understand the effect of these groups on gas production under γ-irradiation, especially on hydrogen formation, and to study the efficiency of energy transfer between chemical groups, several methylene containing polymers with different controlled group concentrations were studied in inert atmosphere. We analyzed the influence of the nature and position of the chemical group using methylene containing copolymers with aliphatic side-chains (different lengths), ester groups in the side-chains (different concentrations) and ester groups in the polymer backbone (different concentrations). Radiation chemical yields of H{sub 2}, CO, CO{sub 2} and CH{sub 4} were determined at room temperature by high resolution mass spectrometry. On the basis of these results, we attempt to obtain a better understanding of the mechanisms involved. It can be observed that crystallinity and aliphatic side-chain have no effect on hydrogen formation. On contrary, esters on side-chain and in the backbone have an important influence on hydrogen formation, with the most important effect when esters groups are in the backbone. In these two kind of materials, energy fraction transferred from methylene to ester groups has been quantified and only 10 wt% (or less) of ester groups are sufficient to protect effectively the aliphatic moiety.

  12. Magnetotransport of Monolayer Graphene with Inert Gas Adsorption in the Quantum Hall Regime

    Science.gov (United States)

    Fukuda, A.; Terasawa, D.; Fujimoto, A.; Kanai, Y.; Matsumoto, K.

    2018-03-01

    The surface of graphene is easily accessible from outside, and thus it is a suitable material to study the effects of molecular adsorption on the electric transport properties. We investigate the magnetotransport of inert-gas-adsorbed monolayer graphene at a temperature of 4.4 K under a magnetic field ranging from 0 to 7 T. We introduce 4He or Ar gas at low temperature to graphene kept inside a sample cell. The magnetoresistance change ΔRxx and Hall resistance change ΔRxy from the pristine graphene are measured as a function of gate voltage and magnetic field for one layer of adsorbates. ΔRxx and ΔRxy show oscillating patterns related to the constant filling factor lines in a Landau-fan diagram. Magnitudes of these quantities are relatively higher around a charge neutral point and may be mass-sensitive. These conditions could be optimized for development of a highly sensitive gas sensor.

  13. Inert gas narcosis disrupts encoding but not retrieval of long term memory.

    Science.gov (United States)

    Hobbs, Malcolm; Kneller, Wendy

    2015-05-15

    Exposure to increased ambient pressure causes inert gas narcosis of which one symptom is long-term memory (LTM) impairment. Narcosis is posited to impair LTM by disrupting information encoding, retrieval (self-guided search), or both. The effect of narcosis on the encoding and retrieval of LTM was investigated by testing the effect of learning-recall pressure and levels of processing (LoP) on the free-recall of word lists in divers underwater. All participants (n=60) took part in four conditions in which words were learnt and then recalled at either low pressure (1.4-1.9atm/4-9msw) or high pressure (4.4-5.0atm/34-40msw), as manipulated by changes in depth underwater: low-low (LL), low-high(LH), high-high (HH), and high-low (HL). In addition, participants were assigned to either a deep or shallow processing condition, using LoP methodology. Free-recall memory ability was significantly impaired only when words were initially learned at high pressure (HH & HL conditions). When words were learned at low pressure and then recalled at low pressure (LL condition) or high pressure (LH condition) free-recall was not impaired. Although numerically superior in several conditions, deeper processing failed to significantly improve free-recall ability in any of the learning-recall conditions. This pattern of results support the hypothesis that narcosis disrupts encoding of information into LTM, while retrieval appears to be unaffected. These findings are discussed in relation to similar effects reported by some memory impairing drugs and the practical implications for workers in pressurised environments. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. High Temperature Testing with Sapphire Fiber White-Light Michelson Interferometers

    Science.gov (United States)

    Barnes, A.; Pedrazzani, J.; May, R.; Murphy, K.; Tran, T.; Coate, J.

    1996-01-01

    In the design of new aerospace materials, developmental testing is conducted to characterize the behavior of the material under severe environmental conditions of high stress, temperature, and vibration. But to test these materials under extreme conditions requires sensors that can perform in harsh environments. Current sensors can only monitor high temperature test samples using long throw instrumentation, but this is inherently less accurate than a surface mounted sensor, and provides no means for fabrication process monitoring. A promising alternative is the use of sapphire optical fiber sensors. Sapphire is an incredibly rugged material, being extremely hard (9 mhos), chemically inert, and having a melting temperature (over 2000 C). Additionally, there is a extensive background of optical fiber sensors upon which to draw for sapphire sensor configurations.

  15. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    2012-01-01

    High Resolution NMR: Theory and Chemical Applications discusses the principles and theory of nuclear magnetic resonance and how this concept is used in the chemical sciences. This book is written at an intermediate level, with mathematics used to augment verbal descriptions of the phenomena. This text pays attention to developing and interrelating four approaches - the steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The style of this book is based on the assumption that the reader has an acquaintance with the general principles of quantum mechanics, but no extensive background in quantum theory or proficiency in mathematics is required. This book begins with a description of the basic physics, together with a brief account of the historical development of the field. It looks at the study of NMR in liquids, including high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. This book is intended to assis...

  16. Wigner's infinite spin representations and inert matter

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Bert [CBPF, Rio de Janeiro (Brazil); Institut fuer Theoretische Physik FU-Berlin, Berlin (Germany)

    2017-06-15

    Positive energy ray representations of the Poincare group are naturally subdivided into three classes according to their mass and spin content: m > 0, m = 0 finite helicity and m = 0 infinite spin. For a long time the localization properties of the massless infinite spin class remained unknown, until it became clear that such matter does not permit compact spacetime localization and its generating covariant fields are localized on semi-infinite space-like strings. Using a new perturbation theory for higher spin fields we present arguments which support the idea that infinite spin matter cannot interact with normal matter and we formulate conditions under which this also could happen for finite spin s > 1 fields. This raises the question of a possible connection between inert matter and dark matter. (orig.)

  17. Gasification of high ash, high ash fusion temperature bituminous coals

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  18. NOx emission control in SI engine by adding argon inert gas to intake mixture

    International Nuclear Information System (INIS)

    Moneib, Hany A.; Abdelaal, Mohsen; Selim, Mohamed Y.E.; Abdallah, Osama A.

    2009-01-01

    The Argon inert gas is used to dilute the intake air of a spark ignition engine to decrease nitrogen oxides and improve the performance of the engine. A research engine Ricardo E6 with variable compression was used in the present work. A special test rig has been designed and built to admit the gas to the intake air of the engine for up to 15% of the intake air. The system could admit the inert gas, oxygen and nitrogen gases at preset amounts. The variables studied included the engine speed, Argon to inlet air ratio, and air to fuel ratio. The results presented here included the combustion pressure, temperature, burned mass fraction, heat release rate, brake power, thermal efficiency, volumetric efficiency, exhaust temperature, brake specific fuel consumption and emissions of CO, CO 2 , NO and O 2 . It was found that the addition of Argon gas to the intake air of the gasoline engine causes the nitrogen oxide to reduce effectively and also it caused the brake power and thermal efficiency of the engine to increase. Mathematical program has been used to obtain the mixture properties and the heat release when the Argon gas is used.

  19. New viable region of an inert Higgs doublet dark matter model with scotogenic extension

    Science.gov (United States)

    Borah, Debasish; Gupta, Aritra

    2017-12-01

    We explore the intermediate dark matter mass regime of the inert Higgs doublet model, approximately between 400 and 550 GeV, which is allowed by latest constraints from direct and indirect detection experiments, but the thermal relic abundance remains suppressed. We extend the model by three copies of right-handed neutrinos, odd under the built-in Z2 symmetry of the model. This discrete Z2 symmetry of the model allows these right-handed neutrinos to couple to the usual lepton doublets through the inert Higgs doublet allowing the possibility of radiative neutrino mass in the scotogenic fashion. Apart from generating nonzero neutrino mass, such an extension can also revive the intermediate dark matter mass regime. The late decay of the lightest right-handed neutrino to dark matter makes it possible for the usual thermally underabundant dark matter in this intermediate mass regime to satisfy the correct relic abundance limit. The revival of this wide intermediate mass range can have relevance not only for direct and indirect search experiments but also for neutrino experiments as the long lifetime of the lightest right-handed neutrino also results in almost vanishing lightest neutrino mass.

  20. Thermal degradation of CR-39 polymer in an inert atmosphere

    International Nuclear Information System (INIS)

    Kalsi, P.C.; Pandey, A.K.; Iyer, R.H.; Singh Mudher, K.D.

    1995-01-01

    The thermal degradation of CR-39 (allyl diglycol carbonate), a polymer widely used in nuclear science and technology, in an inert atmosphere has been studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. The results are compared with the thermal degradation data of the polymer in an air atmosphere. The present studies showed that the thermal degradation of the polymer proceeds in two steps in an argon atmosphere as compared to three steps in air atmosphere. The mass losses in air are higher than that in argon due to the oxidative decomposition of the residue. The kinetics of the different stages of degradation were also evaluated from the TG curves. (author). 7 refs., 1 tab

  1. Muon implantation in inert gases studied by radio frequency spectroscopy

    International Nuclear Information System (INIS)

    Johnson, C; Cottrell, S P; Ghandi, K; Fleming, D G

    2005-01-01

    Diamagnetic and muonium (Mu) fractions formed in low-pressure inert gases, by energetic muon implantation, have been studied using the technique of time-delayed radio frequency muon spin resonance (RF-μSR). Results obtained establish the validity of the long-held view that formation of these species is due only to prompt processes, and in turn confirms that the diamagnetic environment is due to a muon molecular ion, MMu + , and not a bare μ + . In addition, polarization fractions for the diamagnetic and Mu environments have been determined at different pressures, thereby complementing earlier data, and demonstrating that the RF-μSR technique provides polarization fractions in good accord with those obtained using conventional transverse-field muon spin resonance measurements

  2. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  3. The impact of whole human blood on the kinetic inertness of platinum(iv) prodrugs - an HPLC-ICP-MS study.

    Science.gov (United States)

    Theiner, Sarah; Grabarics, Márkó; Galvez, Luis; Varbanov, Hristo P; Sommerfeld, Nadine S; Galanski, Markus; Keppler, Bernhard K; Koellensperger, Gunda

    2018-04-17

    The potential advantage of platinum(iv) complexes as alternatives to classical platinum(ii)-based drugs relies on their kinetic stability in the body before reaching the tumor site and on their activation by reduction inside cancer cells. In this study, an analytical workflow has been developed to investigate the reductive biotransformation and kinetic inertness of platinum(iv) prodrugs comprising different ligand coordination spheres (respectively, lipophilicity and redox behavior) in whole human blood. The distribution of platinum(iv) complexes in blood pellets and plasma was determined by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. An analytical approach based on reversed-phase (RP)-ICP-MS was used to monitor the parent compound and the formation of metabolites using two different extraction procedures. The ligand coordination sphere of the platinum(iv) complexes had a significant impact on their accumulation in red blood cells and on their degree of kinetic inertness in whole human blood. The most lipophilic platinum(iv) compound featuring equatorial chlorido ligands showed a pronounced penetration into blood cells and a rapid reductive biotransformation. In contrast, the more hydrophilic platinum(iv) complexes with a carboplatin- and oxaliplatin-core exerted kinetic inertness on a pharmacologically relevant time scale with notable amounts of the compound accumulated in the plasma fraction.

  4. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Allyl and benzyl ethers of alcohols can be prepared conveniently and in high yield with allyl and benzyl bromide in the presence of solid potassium hydroxide without use of any solvent. Phenols can be converted to allyl ethers but are inert to benzylation under above conditions.

  5. Hydrological performance of dual-substrate-layer green roofs using porous inert substrates with high sorption capacities.

    Science.gov (United States)

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Chenrui

    2017-06-01

    Given that the common medium in existing green roofs is a single layer composed of organic and inorganic substrates, seven pilot-scale dual-substrate-layer extensive green roofs (G1-G7), which include nutrition and adsorption substrate layers, were constructed in this study. The effectiveness of porous inert substrates (activated charcoal, zeolite, pumice, lava, vermiculite and expanded perlite) used as the adsorption substrate for stormwater retention was investigated. A single-substrate-layer green roof (G8) was built for comparison with G1-G7. Despite the larger total rainfall depth (mm) of six types of simulated rains (43.2, 54.6, 76.2, 87.0, 85.2 and 86.4, respectively), the total percent retention of G1-G7 varied between 14% and 82% with an average of 43%, exhibiting better runoff-retaining capacity than G8 based on the maximum potential rainfall storage depth per unit height of adsorption substrate. Regression analysis showed that there was a logarithmic relationship between cumulative rainfall depth with non-zero runoff and stormwater retention for G1-G4 and a linear relationship for G5-G8. To enhance the water retention capacity and extend the service life of dual-substrate-layer extensive green roofs, the mixture of activated charcoal and/or pumice with expanded perlite and/or vermiculite is more suitable as the adsorption substrate than the mixture containing lava and/or zeolite.

  6. Inert gas narcosis and the encoding and retrieval of long-term memory.

    Science.gov (United States)

    Kneller, Wendy; Hobbs, Malcolm

    2013-12-01

    Prior research has indicated that inert gas narcosis (IGN) causes decrements in free recall memory performance and that these result from disruption of either encoding or self-guided search in the retrieval process. In a recent study we provided evidence, using a Levels of Processing approach, for the hypothesis that IGN affects the encoding of new information. The current study sought to replicate these results with an improved methodology. The effect of ambient pressure (111.5-212.8 kPa/1-11 msw vs. 456-516.8 kPa/35-41 msw) and level of processing (shallow vs. deep) on free recall memory performance was measured in 34 divers in the context of an underwater field experiment. Free recall was significantly worse at high ambient pressure compared to low ambient pressure in the deep processing condition (low pressure: M = 5.6; SD = 2.7; high pressure: M = 3.3; SD = 1.4), but not in the shallow processing condition (low pressure: M = 3.9; SD = 1.7; high pressure: M = 3.1; SD = 1.8), indicating IGN impaired memory ability in the deep processing condition. In the shallow water, deep processing improved recall over shallow processing but, significantly, this effect was eliminated in the deep water. In contrast to our earlier study this supported the hypothesis that IGN affects the self-guided search of information and not encoding. It is suggested that IGN may affect both encoding and self-guided search and further research is recommended.

  7. Determination of hydrogen in uranium-niobium-zirconium alloy by inert-gas fusion

    International Nuclear Information System (INIS)

    Carden, W.F.

    1979-12-01

    An improved method has been developed using inert-gas fusion for determining the hydrogen content in uranium-niobium-zirconium (U-7.5Nb-2.5Zr) alloy. The method is applicable to concentrations of hydrogen ranging from 1 to 250 micrograms per gram and may be adjusted for analysis of greater hydrogen concentrations. Hydrogen is determined using a hydrogen determinator. The limit of error for a single determination at the 95%-confidence level (at the 3.7-μg/g-hydrogen level) is +-1.4 micrograms per gram hydrogen

  8. Allowable spent LWR fuel storage temperatures in inert gases, nitrogen, and air

    International Nuclear Information System (INIS)

    Gilbert, E.R.; Cunningham, M.E.; Simonen, E.P.; Thomas, L.E.; Campbell, T.K.; Barnhart, D.M.

    1990-01-01

    Spent fuel in inert dry storage is now a reality in the US; recommended maximum temperature-time conditions are specified in an IBM PC-compatible code. However, spent fuel cannot yet be stored in air because the data and theory needed for predicting allowable temperatures are still being developed. Tests to determine the behavior of spent UO 2 fragments and breached rod specimens in air are providing data that will be used to determine the temperatures that can be allowed for fuel stored in air. 13 refs., 5 figs

  9. Optimal dual-fuel propulsion for minimum inert weight or minimum fuel cost

    Science.gov (United States)

    Martin, J. A.

    1973-01-01

    An analytical investigation of single-stage vehicles with multiple propulsion phases has been conducted with the phasing optimized to minimize a general cost function. Some results are presented for linearized sizing relationships which indicate that single-stage-to-orbit, dual-fuel rocket vehicles can have lower inert weight than similar single-fuel rocket vehicles and that the advantage of dual-fuel vehicles can be increased if a dual-fuel engine is developed. The results also indicate that the optimum split can vary considerably with the choice of cost function to be minimized.

  10. Control characteristics of inert gas recovery plant

    International Nuclear Information System (INIS)

    Mikawa, Hiroji; Kato, Yomei; Kamiya, Kunio

    1980-01-01

    This paper presents a dynamic simulator and the control characteristics for a radioactive inert gas recovery plant which uses a cryogenic liquefying process. The simulator was developed to analyze the operational characteristics and is applicable to gas streams which contain nitrogen, argon, oxygen and krypton. The characteristics analysis of the pilot plant was performed after the accuracy of the simulator was checked using data obtained in fundamental experiments. The relationship between the reflux ratio and krypton concentration in the effluent gas was obtained. The decontamination factor is larger than 10 9 when the reflux ratio is more than 2. 0. The control characteristics of the plant were examined by changing its various parameters. These included the amount of gas to be treated, the heater power inside the evaporator and the liquid nitrogen level in the condenser. These characteristics agreed well with the values obtained in the pilot plant. The results show that the krypton concentration in the effluent gas increases when the liquid nitrogen level is decreased. However, in this case, the krypton concentration can be minimized by applying a feed forward control to the evaporator liquid level controller. (author)

  11. Mn nanoparticles produced by inert gas condensation

    International Nuclear Information System (INIS)

    Ward, M B; Brydson, R; Cochrane, R F

    2006-01-01

    The results from experiments using the inert gas condensation method to produce nanoparticles of manganese are presented. Structural and compositional data have been collected through electron diffraction, EDX (energy dispersive X-ray) and EELS (electron energy loss spectroscopy). Both Mn 3 O 4 and pure Mn particles have been produced. Moisture in untreated helium gas causes the particles to oxidize, whereas running the helium through a liquid nitrogen trap removes the moisture and produces β-Mn particles in a metastable state. The particle sizes and the size distribution have been determined. Particle sizes range from 2nm to above 100 nm, however the majority of particles lie in the range below 20 nm with a modal particle size of 6 nm. As well as the modal particle size of 6 nm, there is another peak in the frequency curve at 16 nm that represents another group particles that lie in the range 12 to 20 nm. The smaller particles are single crystals, but the larger particles appear to have a dense region around their edge with a less dense centre. Determination of their exact nature is ongoing

  12. Dosimetric characterization of chemical-vapor-deposited diamond film irradiated with UV and beta radiation

    Science.gov (United States)

    Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; Barboza-Flores, M.

    2003-03-01

    Diamond is an excellent prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality polycrystalline has renewed the interest in using diamond films as detectors and dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by using chemical vapor deposition. The thermoluminescence (TL) of UV and beta exposed samples shows a glow curve composed of at least four peaks; one located around 587 K presents excellent TL properties suitable for dosimetric applications with ionizing and non ionizing radiation. The TL excitation spectrum exhibits maximum TL efficiency at 220 nm. The samples show regions of linear as well as supralinear behavior as a function or irradiation dose. The linear dose dependence was found for up to sixteen minutes of UV irradiation and 300 Gy for beta irradiated samples. The activation energy and the frequency factor were determined and found in the range of 0.32 - 0.89 eV and 1.1x10^2 - 2x10^8s_-1, respectively. The observed TL performance is reasonable appropriate to justify further investigation of diamond films as radiation dosimeters.

  13. Muon implantation in inert gases studied by radio frequency spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C [ISIS Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Cottrell, S P [ISIS Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire (United Kingdom); Ghandi, K [TRIUMF and Department of Chemistry, University of British Columbia, Vancouver (Canada); Fleming, D G [TRIUMF and Department of Chemistry, University of British Columbia, Vancouver (Canada)

    2005-01-14

    Diamagnetic and muonium (Mu) fractions formed in low-pressure inert gases, by energetic muon implantation, have been studied using the technique of time-delayed radio frequency muon spin resonance (RF-{mu}SR). Results obtained establish the validity of the long-held view that formation of these species is due only to prompt processes, and in turn confirms that the diamagnetic environment is due to a muon molecular ion, MMu{sup +}, and not a bare {mu}{sup +}. In addition, polarization fractions for the diamagnetic and Mu environments have been determined at different pressures, thereby complementing earlier data, and demonstrating that the RF-{mu}SR technique provides polarization fractions in good accord with those obtained using conventional transverse-field muon spin resonance measurements.

  14. Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders.

    Science.gov (United States)

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

    2016-03-01

    Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm(-3), with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  15. SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

    International Nuclear Information System (INIS)

    Boies, Adam M; Girshick, Steven L; Roberts, Jeffrey T; Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane

    2009-01-01

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO 2 ) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO 2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO 2 coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 0 C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10 7 particles cm -3 .

  16. Deposition of Size-Selected Cu Nanoparticles by Inert Gas Condensation

    Directory of Open Access Journals (Sweden)

    Martínez E

    2009-01-01

    Full Text Available Abstract Nanometer size-selected Cu clusters in the size range of 1–5 nm have been produced by a plasma-gas-condensation-type cluster deposition apparatus, which combines a grow-discharge sputtering with an inert gas condensation technique. With this method, by controlling the experimental conditions, it was possible to produce nanoparticles with a strict control in size. The structure and size of Cu nanoparticles were determined by mass spectroscopy and confirmed by atomic force microscopy (AFM and scanning electron transmission microscopy (STEM measurements. In order to preserve the structural and morphological properties, the energy of cluster impact was controlled; the energy of acceleration of the nanoparticles was in near values at 0.1 ev/atom for being in soft landing regime. From SEM measurements developed in STEM-HAADF mode, we found that nanoparticles are near sized to those values fixed experimentally also confirmed by AFM observations. The results are relevant, since it demonstrates that proper optimization of operation conditions can lead to desired cluster sizes as well as desired cluster size distributions. It was also demonstrated the efficiency of the method to obtain size-selected Cu clusters films, as a random stacking of nanometer-size crystallites assembly. The deposition of size-selected metal clusters represents a novel method of preparing Cu nanostructures, with high potential in optical and catalytic applications.

  17. High-Throughput Screening and Quantitative Chemical Ranking for Sodium-Iodide Symporter Inhibitors in ToxCast Phase I Chemical Library.

    Science.gov (United States)

    Wang, Jun; Hallinger, Daniel R; Murr, Ashley S; Buckalew, Angela R; Simmons, Steven O; Laws, Susan C; Stoker, Tammy E

    2018-05-01

    Thyroid uptake of iodide via the sodium-iodide symporter (NIS) is the first step in the biosynthesis of thyroid hormones that are critical for health and development in humans and wildlife. Despite having long been a known target of endocrine disrupting chemicals such as perchlorate, information regarding NIS inhibition activity is still unavailable for the vast majority of environmental chemicals. This study applied a previously validated high-throughput approach to screen for NIS inhibitors in the ToxCast phase I library, representing 293 important environmental chemicals. Here 310 blinded samples were screened in a tiered-approach using an initial single-concentration (100 μM) radioactive-iodide uptake (RAIU) assay, followed by 169 samples further evaluated in multi-concentration (0.001 μM-100 μM) testing in parallel RAIU and cell viability assays. A novel chemical ranking system that incorporates multi-concentration RAIU and cytotoxicity responses was also developed as a standardized method for chemical prioritization in current and future screenings. Representative chemical responses and thyroid effects of high-ranking chemicals are further discussed. This study significantly expands current knowledge of NIS inhibition potential in environmental chemicals and provides critical support to U.S. EPA's Endocrine Disruptor Screening Program (EDSP) initiative to expand coverage of thyroid molecular targets, as well as the development of thyroid adverse outcome pathways (AOPs).

  18. NERI FINAL TECHNICAL REPORT, DE-FC07-O5ID14647, OPTIMIZATION OF OXIDE COMPOUNDS FOR ADVANCED INERT MATRIX MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    PI: JUAN C. NINO, ASSOCIATE PROFESSOR

    2009-01-11

    In order to reduce the current excesses of plutonium (both weapon grade and reactor grade) and other transuranium elements, a concept of inert matrix fuel (IMF) has been proposed for an uranium free transmutation of fissile actinides which excludes continuous uranium-plutonium conversion in thermal reactors and advanced systems. Magnesium oxide (MgO) is a promising candidate for inert matrix (IM) materials due to its high melting point (2827 C), high thermal conductivity (13 W/K {center_dot} m at 1000 C), good neutronic properties, and irradiation stability However, MgO reacts with water and hydrates easily, which prevents it from being used in light water reactors (LWRs) as an IM. To improve the hydration resistance of MgO-based inert matrix materials, Medvedev and coworkers have recently investigated the introduction of a secondary phase that acts as a hydration barrier. An MgO-ZrO{sub 2} composite was specifically studied and the results showed that the composite exhibited improved hydration resistance than pure MgO. However, ZrO{sub 2} is insoluble in most acids except HF, which is undesirable for fuel reprocessing. Moreover, the thermal conductivity of ZrO{sub 2} is low and typically less than 3 W {center_dot} m{sup -1} {center_dot} K{sup -1} at 1000 C. In search for an alternative composite strategy, Nd{sub 2}Zr{sub 2}O{sub 7}, an oxide compound with pyrochlore structure, has been proposed recently as a corrosion resistant phase, and MgO-Nd{sub 2}Zr{sub 2}O{sub 7} composites have been investigated as potential IM materials. An adequate thermal conductivity of 6 W {center_dot} m{sup -} 1 {center_dot} K{sup -1} at 1000 C for the MgO-Nd{sub 2}Zr{sub 2}O{sub 7} composite with 90 vol% MgO was recently calculated and reported. Other simulations proposed that the MgO-pyrochlore composites could exhibit higher radiation stability than previously reported. Final optimization of the composite microstructure was performed on the 70 vol% MgO-Nd{sub 2}Zr{sub 2}O{sub 7

  19. One-step microwave plasma enhanced chemical vapor deposition (MW-PECVD) for transparent superhydrophobic surface

    Science.gov (United States)

    Thongrom, Sukrit; Tirawanichakul, Yutthana; Munsit, Nantakan; Deangngam, Chalongrat

    2018-02-01

    We demonstrate a rapid and environmental friendly fabrication technique to produce optically clear superhydrophobic surfaces using poly (dimethylsiloxane) (PDMS) as a sole coating material. The inert PDMS chain is transformed into a 3-D irregular solid network through microwave plasma enhanced chemical vapor deposition (MW-PECVD) process. Thanks to high electron density in the microwave-activated plasma, coating can be done in just a single step with rapid deposition rate, typically much shorter than 10 s. Deposited layers show excellent superhydrophobic properties with water contact angles of ∼170° and roll-off angles as small as ∼3°. The plasma-deposited films can be ultrathin with thicknesses under 400 nm, greatly diminishing the optical loss. Moreover, with appropriate coating conditions, the coating layer can even enhance the transmission over the entire visible spectrum due to a partial anti-reflection effect.

  20. Comprehensive genetic analysis of early host body reactions to the bioactive and bio-inert porous scaffolds.

    Directory of Open Access Journals (Sweden)

    Tomo Ehashi

    Full Text Available To design scaffolds for tissue regeneration, details of the host body reaction to the scaffolds must be studied. Host body reactions have been investigated mainly by immunohistological observations for a long time. Despite of recent dramatic development in genetic analysis technologies, genetically comprehensive changes in host body reactions are hardly studied. There is no information about host body reactions that can predict successful tissue regeneration in the future. In the present study, porous polyethylene scaffolds were coated with bioactive collagen or bio-inert poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate (PMB and were implanted subcutaneously and compared the host body reaction to those substrates by normalizing the result using control non-coat polyethylene scaffold. The comprehensive analyses of early host body reactions to the scaffolds were carried out using a DNA microarray assay. Within numerous genes which were expressed differently among these scaffolds, particular genes related to inflammation, wound healing, and angiogenesis were focused upon. Interleukin (IL-1β and IL-10 are important cytokines in tissue responses to biomaterials because IL-1β promotes both inflammation and wound healing and IL-10 suppresses both of them. IL-1β was up-regulated in the collagen-coated scaffold. Collagen-specifically up-regulated genes contained both M1- and M2-macrophage-related genes. Marked vessel formation in the collagen-coated scaffold was occurred in accordance with the up-regulation of many angiogenesis-inducible factors. The DNA microarray assay provided global information regarding the host body reaction. Interestingly, several up-regulated genes were detected even on the very bio-inert PMB-coated surfaces and those genes include inflammation-suppressive and wound healing-suppressive IL-10, suggesting that not only active tissue response but also the inert response may relates to these genetic

  1. Comprehensive Genetic Analysis of Early Host Body Reactions to the Bioactive and Bio-Inert Porous Scaffolds

    Science.gov (United States)

    Ehashi, Tomo; Takemura, Taro; Hanagata, Nobutaka; Minowa, Takashi; Kobayashi, Hisatoshi; Ishihara, Kazuhiko; Yamaoka, Tetsuji

    2014-01-01

    To design scaffolds for tissue regeneration, details of the host body reaction to the scaffolds must be studied. Host body reactions have been investigated mainly by immunohistological observations for a long time. Despite of recent dramatic development in genetic analysis technologies, genetically comprehensive changes in host body reactions are hardly studied. There is no information about host body reactions that can predict successful tissue regeneration in the future. In the present study, porous polyethylene scaffolds were coated with bioactive collagen or bio-inert poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) and were implanted subcutaneously and compared the host body reaction to those substrates by normalizing the result using control non-coat polyethylene scaffold. The comprehensive analyses of early host body reactions to the scaffolds were carried out using a DNA microarray assay. Within numerous genes which were expressed differently among these scaffolds, particular genes related to inflammation, wound healing, and angiogenesis were focused upon. Interleukin (IL)-1β and IL-10 are important cytokines in tissue responses to biomaterials because IL-1β promotes both inflammation and wound healing and IL-10 suppresses both of them. IL-1β was up-regulated in the collagen-coated scaffold. Collagen-specifically up-regulated genes contained both M1- and M2-macrophage-related genes. Marked vessel formation in the collagen-coated scaffold was occurred in accordance with the up-regulation of many angiogenesis-inducible factors. The DNA microarray assay provided global information regarding the host body reaction. Interestingly, several up-regulated genes were detected even on the very bio-inert PMB-coated surfaces and those genes include inflammation-suppressive and wound healing-suppressive IL-10, suggesting that not only active tissue response but also the inert response may relates to these genetic regulations. PMID:24454803

  2. Pulmonary distribution of [sup 99m]Tc-technegas; A comparative study of radioactive inert gases

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Kenji; Shimada, Takao; Mori, Yutaka; Goto, Eisuke; Hirasawa, Yukinori [Jikei Univ., Tokyo (Japan). School of Medicine; Tominaga, Shigeru

    1992-10-01

    Technetium 99m-technegas ([sup 99m]Tc-gas), which consists of fine particles, is produced in carbon crucibles burned at 2500degC. In this study, the particle size of [sup 99m]Tc-gas was measured and the pulmonary distribution of [sup 99m]Tc-gas was assessed in 28 patients with various pulmonary diseases. Most particles were 5[approx]30 nm in diameter as determined by electron microscopy. In a clinical study, about 37 MBq of [sup 99m]Tc-gas was inhaled three times during deep breathing in a sitting position. In a comparative study with radioactive inert gases ([sup 133]Xe, [sup 81m]Kr), [sup 99m]Tc-gas showed a similar distribution to the inert gas in most patients, although some with obstructive disease showed hot spots in the lung fields. In patients with severe obstructive change, marked deposits of [sup 99m]Tc-gas was noted in the central airways, but [sup 99m]Tc-gas penetrated to the peripheral lung field. This result suggests that [sup 99m]Tc-gas can be used to evaluate ventilatory function even in patients with chronic obstructive pulmonary diseases. (author).

  3. Reducibility of ceria-lanthana mixed oxides under temperature programmed hydrogen and inert gas flow conditions

    International Nuclear Information System (INIS)

    Bernal, S.; Blanco, G.; Cifredo, G.; Perez-Omil, J.A.; Pintado, J.M.; Rodriguez-Izquierdo, J.M.

    1997-01-01

    The present paper deals with the preparation and characterization of La/Ce mixed oxides, with La molar contents of 20, 36 and 57%. We carry out the study of the structural, textural and redox properties of the mixed oxides, comparing our results with those for pure ceria. For this aim we use temperature programmed reduction (TPR), temperature programmed desorption (TPD), nitrogen physisorption at 77 K, X-ray diffraction and high resolution electron microscopy. The mixed oxides are more easy to reduce in a flow of hydrogen than ceria. Moreover, in an inert gas flow they release oxygen in higher amounts and at lower temperatures than pure CeO 2 . The textural stability of the mixed oxides is also improved by incorporation of lanthana. All these properties make the ceria-lanthana mixed oxides interesting alternative candidates to substitute ceria in three-way catalyst formulations. (orig.)

  4. Effect of ''outer'' sources and dissipative processes on abundance of inert gases in atmospheres of the Earth group planets

    International Nuclear Information System (INIS)

    Pavlov, A.K.

    1981-01-01

    The problem of abundance of inert gases in atmospheres of the Earth group planets is discussed. It is shown that introduction of He, Ne and 36 Ar into the Mars and Mercury atmospheres with interplanetary dust and from other external sources require the presence of special mechanisms of losses for these gases. For the Mars atmosphere dissipation on atmosphere interaction with solar wind during the periods of anomalously low temperatures is a probable mechanisms of Ne and 36 Ar losses. For the Mercury thermal dissipation for He and polar wind for other inert gases are possible. For all the planets of the Earth group dissipation on interaction with solar wind and introduction with interplanetary dust could play an important role at the early stages of evolution of planets [ru

  5. Repository emplacement costs for Al-clad high enriched uranium spent fuel

    International Nuclear Information System (INIS)

    McDonell, W.R.; Parks, P.B.

    1994-01-01

    A range of strategies for treatment and packaging of Al-clad high-enriched uranium (HEU) spent fuels to prevent or delay the onset of criticality in a geologic repository was evaluated in terms of the number of canisters produced and associated repository costs incurred. The results indicated that strategies in which neutron poisons were added to consolidated forms of the U-Al alloy fuel generally produced the lowest number of canisters and associated repository costs. Chemical processing whereby the HEU was removed from the waste form was also a low cost option. The repository costs generally increased for isotopic dilution strategies, because of the substantial depleted uranium added. Chemical dissolution strategies without HEU removal were also penalized because of the inert constituents in the final waste glass form. Avoiding repository criticality by limiting the fissile mass content of each canister incurred the highest repository costs

  6. Dynamics of soluble and inert pollutant concentrations in linear and deterministic systems with time varying parameters

    International Nuclear Information System (INIS)

    Meltzer, M.

    1977-04-01

    The tracer theory in steady and non-steady systems is presented. The unsteady system was applied in the study of the concentration dynamics of the National Water Carrier in Israel. A method that uses Bromine 82 for the investigation of the transfer time distribution and of the dynamics of inert matter concentration in the system is desribed. (B.G.)

  7. Enhanced signal generation for use in the analysis of synthetic pyrethroids using chemical ionization tandem quadrupole ion trap mass spectrometry.

    Science.gov (United States)

    Sichilongo, Kwenga

    2004-12-01

    Synthetic pyrethroids fragment extensively under electron ionization (EI) conditions to give low mass ions, most of them with the same m/z ratios. This fragmentation is primarily due to the labile ester linkage found in these compounds. In this research we established the best gas chromatography (GC) conditions in the EI mode that served as a benchmark in the development of a chemical ionization (CI) protocol for ten selected synthetic pyrethroids. Based on proton affinity data, several reagent gases were evaluated in the positive CI ionization mode. Methanol was found to produce higher average ion counts relative to the other gases evaluated, which led to the development of an optimized method consisting of selective ejection chemical ionization (SECI) and MS/MS. Standard stainless steel ion trap electrodes produced significant degradation of chromatographic performance on late eluting compounds, which was attributed to electrode surface chemistry. A dramatic improvement in signal-to-noise (S/N) ratios was observed when the chromatographically inert Silcosteel coated electrodes were used. The resulting method, that has significant S/N ratio improvements resulting from a combination of septum programmable injections (SPI), optimized CI and inert Silcosteel-coated electrodes, was used to determine instrument detection limits.

  8. Water in the presence of inert Lennard-Jones obstacles

    Science.gov (United States)

    Kurtjak, Mario; Urbic, Tomaz

    2014-04-01

    Water confined by the presence of a 'sea' of inert obstacles was examined. In the article, freely mobile two-dimensional Mercedes-Benz (MB) water put to a disordered, but fixed, matrix of Lennard-Jones disks was studied by the Monte Carlo computer simulations. For the MB water molecules in the matrix of Lennard-Jones disks, we explored the structures, hydrogen-bond-network formation and thermodynamics as a function of temperature and size and density of matrix particles. We found that the structure of model water is perturbed by the presence of the obstacles. Density of confined water, which was in equilibrium with the bulk water, was smaller than the density of the bulk water and the temperature dependence of the density of absorbed water did not show the density anomaly in the studied temperature range. The behaviour observed as a consequence of confinement is similar to that of increasing temperature, which can for a matrix lead to a process similar to capillary evaporation. At the same occupancy of space, smaller matrix molecules cause higher destruction effect on the absorbed water molecules than the bigger ones. We have also tested the hypothesis that at low matrix densities the obstacles induce an increased ordering and 'hydrogen bonding' of the MB model molecules, relative to pure fluid, while at high densities the obstacles reduce MB water structuring, as they prevent the fluid to form good 'hydrogen-bonding' networks. However, for the size of matrix molecules similar to that of water, we did not observe this effect.

  9. Dark Matter candidate in Inert Doublet Model with additional local gauge symmetry U (1)

    International Nuclear Information System (INIS)

    Gaitán, R.; De Oca, J.H. Montes; Garcés, E. A.; Cabral-Rosetti, L. G.

    2016-01-01

    We consider the Inert Doublet Model (IDM) with an additional local gauge symmetry U (1) and a complex singlet scalar to break the symmetry U (1). The continuous symmetry U (1) is introduced to control the CP-conserving interaction instead of some discrete symmetries as usually. We present the mass spectrum for neutral scalar and gauge bosons and the values of the charges under U (1) for which the model could have a candidate to dark matter. (paper)

  10. Characterisation of silicon carbide films deposited by plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Iliescu, Ciprian; Chen Bangtao; Wei Jiashen; Pang, A.J.

    2008-01-01

    The paper presents a characterisation of amorphous silicon carbide films deposited in plasma-enhanced chemical vapour deposition (PECVD) reactors for MEMS applications. The main parameter was optimised in order to achieve a low stress and high deposition rate. We noticed that the high frequency mode (13.56 MHz) gives a low stress value which can be tuned from tensile to compressive by selecting the correct power. The low frequency mode (380 kHz) generates high compressive stress (around 500 MPa) due to ion bombardment and, as a result, densification of the layer achieved. Temperature can decrease the compressive value of the stress (due to annealing effect). A low etching rate of the amorphous silicon carbide layer was noticed for wet etching in KOH 30% at 80 o C (around 13 A/min) while in HF 49% the layer is practically inert. A very slow etching rate of amorphous silicon carbide layer in XeF 2 -7 A/min- was observed. The paper presents an example of this application: PECVD-amorphous silicon carbide cantilevers fabricated using surface micromachining by dry-released technique in XeF 2

  11. Electro-chemical deposition of nano hydroxyapatite-zinc coating on titanium metal substrate.

    Science.gov (United States)

    El-Wassefy, N A; Reicha, F M; Aref, N S

    2017-08-13

    Titanium is an inert metal that does not induce osteogenesis and has no antibacterial properties; it is proposed that hydroxyapatite coating can enhance its bioactivity, while zinc can contribute to antibacterial properties and improve osseointegration. A nano-sized hydroxyapatite-zinc coating was deposited on commercially pure titanium using an electro-chemical process, in order to increase its surface roughness and enhance adhesion properties. The hydroxyapatite-zinc coating was attained using an electro-chemical deposition in a solution composed of a naturally derived calcium carbonate, di-ammonium hydrogen phosphate, with a pure zinc metal as the anode and titanium as the cathode. The applied voltage was -2.5 for 2 h at a temperature of 85 °C. The resultant coating was characterized for its surface morphology and chemical composition using a scanning electron microscope (SEM), energy dispersive x-ray spectroscope (EDS), and Fourier transform infrared (FT-IR) spectrometer. The coated specimens were also evaluated for their surface roughness and adhesion quality. Hydroxyapatite-zinc coating had shown rosette-shaped, homogenous structure with nano-size distribution, as confirmed by SEM analysis. FT-IR and EDS proved that coatings are composed of hydroxyapatite (HA) and zinc. The surface roughness assessment revealed that the coating procedure had significantly increased average roughness (Ra) than the control, while the adhesive tape test demonstrated a high-quality adhesive coat with no laceration on tape removal. The developed in vitro electro-chemical method can be employed for the deposition of an even thickness of nano HA-Zn adhered coatings on titanium substrate and increases its surface roughness significantly.

  12. Concept study of a novel energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) device for vibration control of harmonically-excited structures

    International Nuclear Information System (INIS)

    Salvi, Jonathan; Giaralis, Agathoklis

    2016-01-01

    A novel dynamic vibration absorber (DVA) configuration is introduced for simultaneous vibration suppression and energy harvesting from oscillations typically exhibited by large-scale low-frequency engineering structures and structural components. The proposed configuration, termed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) comprises a mass grounded via an in-series electromagnetic motor (energy harvester)-inerter layout, and attached to the primary structure through linear spring and damper in parallel connection. The governing equations of motion are derived and solved in the frequency domain, for the case of harmonically-excited primary structures, here modelled as damped single-degree- of-freedom (SDOF) systems. Comprehensive parametric analyses proved that by varying the mass amplification property of the grounded inerter, and by adjusting the stiffness and the damping coefficients using simple optimum tuning formulae, enhanced vibration suppression (in terms of primary structure peak displacement) and energy harvesting (in terms of relative velocity at the terminals of the energy harvester) may be achieved concurrently and at nearresonance frequencies, for a fixed attached mass. Hence, the proposed EH-TMDI allows for relaxing the trade-off between vibration control and energy harvesting purposes, and renders a dual-objective optimisation a practically-feasible, reliable task. (paper)

  13. Can nanofluidic chemical release enable fast, high resolution neurotransmitter-based neurostimulation?

    Directory of Open Access Journals (Sweden)

    Peter D Jones

    2016-03-01

    Full Text Available Artificial chemical stimulation could provide improvements over electrical neurostimulation. Physiological neurotransmission between neurons relies on the nanoscale release and propagation of specific chemical signals to spatially-localized receptors. Current knowledge of nanoscale fluid dynamics and nanofluidic technology allows us to envision artificial mechanisms to achieve fast, high resolution neurotransmitter release. Substantial technological development is required to reach this goal. Nanofluidic technology — rather than microfluidic — will be necessary; this should come as no surprise given the nanofluidic nature of neurotransmission.This perspective reviews the state of the art of high resolution electrical neuroprostheses and their anticipated limitations. Chemical release rates from nanopores are compared to rates achieved at synapses and with iontophoresis. A review of microfluidic technology justifies the analysis that microfluidic control of chemical release would be insufficient. Novel nanofluidic mechanisms are discussed, and we propose that hydrophobic gating may allow control of chemical release suitable for mimicking neurotransmission. The limited understanding of hydrophobic gating in artificial nanopores and the challenges of fabrication and large-scale integration of nanofluidic components are emphasized. Development of suitable nanofluidic technology will require dedicated, long-term efforts over many years.

  14. High Molecular Weight Polymers in the New Chemicals Program

    Science.gov (United States)

    There are three categories or types of High Molecular Weight (HMW, 10,000 daltons) polymers typically reviewed by the New Chemicals Program: Soluble, insoluble, and water absorbing. Each of the three types are treated differently.

  15. Principles for disposal of radioactive and chemical hazardous wastes

    International Nuclear Information System (INIS)

    Merz, E. R.

    1991-01-01

    The double hazard of mixed wastes is characterized by several criteria: radioactivity on the one hand, and chemical toxicity, flammability, corrosiveness as well as chemical reactivity on the other hand. Chemotoxic waste normally has a much more complex composition than radioactive waste and appears in much larger quantities. However, the two types of waste have some properties in common when it comes to their long-term impact on health and the environment. In order to minimize the risk associated with mixed waste management, the material assigned for ultimate disposal should be thoroughly detoxified, inertized, or mineralized prior to conditioning and packaging. Good control over the environmental consequence of waste disposal requires that detailed criteria for tolerable contamination should be established, and that compliance with these criteria can be demonstrated. For radioactive waste, there has been an extensive international development of criteria to protect human health. For non-radioactive waste, derived criteria exist only for a limited number of substances

  16. A roadmap to high quality chemically prepared graphene

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-22

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

  17. A roadmap to high quality chemically prepared graphene

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  18. Detection of chemical explosives using multiple photon signatures

    International Nuclear Information System (INIS)

    Loschke, K.W.; Dunn, W.L.

    2008-01-01

    Full text: A template-matching procedure to aid in rapid detection of improvised explosive devices (IEDs) is being investigated. Multiple photon-scattered and photon-induced positron annihilation radiation responses are being used as part of a photon-neutron signature-based radiation scanning (SBRS) approach (see companion reference for description of the neutron component), in an attempt to detect chemical explosives at safe standoff distances. Many past and present photon interrogation methods are based on imaging. Imaging techniques seek to determine at high special resolution the internal structure of a target of interest. Our technique simply seeks to determine if an unknown target contains a detectable amount of chemical explosives by comparing multiple responses (signatures) that depend on both density and composition of portions of a target. In the photon component, beams of photons are used to create back-streaming signatures, which are dependent on the density and composition of part of the target being interrogated. These signatures are compared to templates, which are collections of the same signatures if the interrogated volume contained a significant amount of explosives. The signature analysis produces a figure-of-merit and a standard deviation of the figure-of-merit. These two metrics are used to filter safe from dangerous targets. Experiments have been conducted that show that explosive surrogates (fertilizers) can be distinguished from several inert materials using these photon signatures, demonstrating that these signatures can be used effectively to help IEDs

  19. Inert Reassessment Document for Ethylene Glycol

    Science.gov (United States)

    Ethylene Glycol has many uses and are also used as antifreeze and deicers, as solvents, humectants, as chemical intermediates in the synthesis of other chemicals, and as components of many products such as brake fluids, lubricants, inks,and lacquers.

  20. Beyond "Inert" Ideas to Teaching General Chemistry from Rich Contexts: Visualizing the Chemistry of Climate Change (VC3)

    Science.gov (United States)

    Mahaffy, Peter G.; Holme, Thomas A.; Martin-Visscher, Leah; Martin, Brian E.; Versprille, Ashley; Kirchhoff, Mary; McKenzie, Lallie; Town, Marcy

    2017-01-01

    As one approach to moving beyond transmitting "inert" ideas to chemistry students, we use the term "teaching from rich contexts" to describe implementations of case studies or context-based learning based on systems thinking that provide deep and rich opportunities for learning crosscutting concepts through contexts. This…

  1. Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Kmetz, M.A.

    1992-01-01

    Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

  2. Chemical stability of high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    A review of the available studies on the chemical stability of the high temperature superconductors (HTS) in various environments was made. The La(1.8)Ba(0.2)CuO4 HTS is unstable in the presence of H2O, CO2, and CO. The YBa2Cu3O(7-x) superconductor is highly susceptible to degradation in different environments, especially water. The La(2-x)Ba(x)CuO4 and Bi-Sr-Ca-Cu-O HTS are relatively less reactive than the YBa2Cu3O(7-x). Processing of YBa2Cu3O(7-x) HTS in purified oxygen, rather than in air, using high purity noncarbon containing starting materials is recommended. Exposure of this HTS to the ambient atmosphere should also be avoided at all stages during processing and storage. Devices and components made out of these oxide superconductors would have to be protected with an impermeable coating of a polymer, glass, or metal to avoid deterioration during use.

  3. Optimization of Gas Composition Used in Plasma Chemical Vaporization Machining for Figuring of Reaction-Sintered Silicon Carbide with Low Surface Roughness.

    Science.gov (United States)

    Sun, Rongyan; Yang, Xu; Ohkubo, Yuji; Endo, Katsuyoshi; Yamamura, Kazuya

    2018-02-05

    In recent years, reaction-sintered silicon carbide (RS-SiC) has been of interest in many engineering fields because of its excellent properties, such as its light weight, high rigidity, high heat conductance and low coefficient of thermal expansion. However, RS-SiC is difficult to machine owing to its high hardness and chemical inertness and because it contains multiple components. To overcome the problem of the poor machinability of RS-SiC in conventional machining, the application of atmospheric-pressure plasma chemical vaporization machining (AP-PCVM) to RS-SiC was proposed. As a highly efficient and damage-free figuring technique, AP-PCVM has been widely applied for the figuring of single-component materials, such as Si, SiC, quartz crystal wafers, and so forth. However, it has not been applied to RS-SiC since it is composed of multiple components. In this study, we investigated the AP-PCVM etching characteristics for RS-SiC by optimizing the gas composition. It was found that the different etching rates of the different components led to a large surface roughness. A smooth surface was obtained by applying the optimum gas composition, for which the etching rate of the Si component was equal to that of the SiC component.

  4. Modification of Structure and Tribological Properties of the Surface Layer of Metal-Ceramic Composite under Electron Irradiation in the Plasmas of Inert Gases

    Science.gov (United States)

    Ovcharenko, V. E.; Ivanov, K. V.; Mohovikov, A. A.; Yu, B.; Xu, Yu; Zhong, L.

    2018-01-01

    Metal-ceramic composites are the main materials for high-load parts in tribomechanical systems. Modern approaches to extend the operation life of tribomechanical systems are based on increasing the strength and tribological properties of the surface layer having 100 to 200 microns in depth. The essential improvement of the properties occurs when high dispersed structure is formed in the surface layer using high-energy processing. As a result of the dispersed structure formation the more uniform distribution of elastic stresses takes place under mechanical or thermal action, the energy of stress concentrators emergence significantly increases and the probability of internal defects formation reduces. The promising method to form the dispersed structure in the surface layer is pulse electron irradiation in the plasmas of inert gases combining electron irradiation and ion bombardment in one process. The present work reports upon the effect of pulse electron irradiation in plasmas of different inert gases with different atomic mass and ionization energy on the structure and tribological properties of the surface layer of TiC/(Ni-Cr) metal-ceramic composite with the volume ratio of the component being 50:50. It is experimentally shown that high-dispersed heterophase structure with a fraction of nanosized particles is formed during the irradiation. Electron microscopy study reveals that refining of the initial coarse TiC particles occurs via their dissolution in the molten metal binder followed by the precipitation of secondary fine particles in the interparticle layers of the binder. The depth of modified layer and the fraction of nanosized particles increase when the atomic number of the plasma gas increases and ionization energy decreases. The wear resistance of metal-ceramic composite improves in accordance to the formation of nanocrystalline structure in the surface layer.

  5. Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-10-12

    Through radiolytic and thermolytic reactions, Hanford tank wastes generate and retain a variety of gases, including hydrogen, nitrous oxide, methane (and other hydrocarbons), ammonia, and nitrogen. This gas generation can be expected to continue during processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The generation rates in the WTP will change from those for the in-situ tank waste because of different process temperatures, different dose rates produced by in-process changes in the proportions of solid and liquid, and dilution of the waste liquid. The flammability of the generated gas that is continuously released, and of any retained gas that might be released into a vessel headspace in quantity due to a spontaneous release, depends on the concentrations not only of the fuel gases—primarily hydrogen (H2), methane, other hydrocarbons, and ammonia—but of the oxidizer nitrous oxide (N2O). As a result of high concentrations of N2O, some gas mixtures are “self-flammable” (i.e., ignition can occur when no air is present because N2O provides the only oxidizer needed). Self-flammability could potentially reduce the effectiveness of using a nitrogen (N2) purge in the headspace as a flammability control, if its effects are not accounted for. A given amount of inertant gas (N2) can accommodate only a certain amount of a generated self-flammable gas before the mixture with inertant gas becomes flammable.

  6. Control of degradation of spent LWR [light-water reactor] fuel during dry storage in an inert atmosphere

    International Nuclear Information System (INIS)

    Cunningham, M.E.; Simonen, E.P.; Allemann, R.T.; Levy, I.S.; Hazelton, R.F.

    1987-10-01

    Dry storage of Zircaloy-clad spent fuel in inert gas (referred to as inerted dry storage or IDS) is being developed as an alternative to water pool storage of spent fuel. The objectives of the activities described in this report are to identify potential Zircaloy degradation mechanisms and evaluate their applicability to cladding breach during IDS, develop models of the dominant Zircaloy degradation mechanisms, and recommend cladding temperature limits during IDS to control Zircaloy degradation. The principal potential Zircaloy cladding breach mechanisms during IDS have been identified as creep rupture, stress corrosion cracking (SCC), and delayed hydride cracking (DHC). Creep rupture is concluded to be the primary cladding breach mechanism during IDS. Deformation and fracture maps based on creep rupture were developed for Zircaloy. These maps were then used as the basis for developing spent fuel cladding temperature limits that would prevent cladding breach during a 40-year IDS period. The probability of cladding breach for spent fuel stored at the temperature limit is less than 0.5% per spent fuel rod. 52 refs., 7 figs., 1 tab

  7. From simple to complex and backwards. Chemical reactions under very high pressure

    International Nuclear Information System (INIS)

    Bini, Roberto; Ceppatelli, Matteo; Citroni, Margherita; Schettino, Vincenzo

    2012-01-01

    Highlights: ► High pressure reactivity of several molecular systems. ► Reaction kinetics and dynamics in high density conditions. ► Key role of optical pumping and electronic excitation. ► Perspectives for the synthesis of hydrogen. - Abstract: High pressure chemical reactions of molecular systems are discussed considering the various factors that can affect the reactivity. These include steric hindrance and geometrical constraints in the confined environment of crystals at high pressure, changes of the free energy landscape with pressure, photoactivation by two-photon absorption, local and collective effects. A classification of the chemical reactions at high pressure is attempted on the basis of the prevailing factors.

  8. Role of inert gases in first wall phenomena in fusion devices

    International Nuclear Information System (INIS)

    Das, S.K.

    1979-01-01

    The first wall surfaces of fusion devices will be exposed to bombardment by inert gaseous projectiles such as helium. The flux, energy and angular distribution of the helium radiation will depend not only on the type of device but also on its design parameters. For near term tokamak devices, the first wall surface phenomena caused by helium bombardment that appear to be quite important are physical sputtering and radiation blistering. Examples of these processes for a number of first wall candidate materials are discussed. While the physical sputtering phenomen is well understood, the mechanism of blister formation is still not fully understood. The various models proposed for radiation blistering of metal during helium bombardment is critically reviewed in the light of most recent experimental results

  9. High-throughput dietary exposure predictions for chemical migrants from food contact substances for use in chemical prioritization.

    Science.gov (United States)

    Biryol, Derya; Nicolas, Chantel I; Wambaugh, John; Phillips, Katherine; Isaacs, Kristin

    2017-11-01

    Under the ExpoCast program, United States Environmental Protection Agency (EPA) researchers have developed a high-throughput (HT) framework for estimating aggregate exposures to chemicals from multiple pathways to support rapid prioritization of chemicals. Here, we present methods to estimate HT exposures to chemicals migrating into food from food contact substances (FCS). These methods consisted of combining an empirical model of chemical migration with estimates of daily population food intakes derived from food diaries from the National Health and Nutrition Examination Survey (NHANES). A linear regression model for migration at equilibrium was developed by fitting available migration measurements as a function of temperature, food type (i.e., fatty, aqueous, acidic, alcoholic), initial chemical concentration in the FCS (C 0 ) and chemical properties. The most predictive variables in the resulting model were C 0 , molecular weight, log K ow , and food type (R 2 =0.71, pchemicals identified via publicly-available data sources as being present in polymer FCSs were predicted for 12 food groups (combinations of 3 storage temperatures and food type). The model was parameterized with screening-level estimates of C 0 based on the functional role of chemicals in FCS. By combining these concentrations with daily intakes for food groups derived from NHANES, population ingestion exposures of chemical in mg/kg-bodyweight/day (mg/kg-BW/day) were estimated. Calibrated aggregate exposures were estimated for 1931 chemicals by fitting HT FCS and consumer product exposures to exposures inferred from NHANES biomonitoring (R 2 =0.61, pchemicals), they can provide critical refinement to aggregate exposure predictions used in risk-based chemical priority-setting. Published by Elsevier Ltd.

  10. High-throughput selection for cellulase catalysts using chemical complementation.

    Science.gov (United States)

    Peralta-Yahya, Pamela; Carter, Brian T; Lin, Hening; Tao, Haiyan; Cornish, Virginia W

    2008-12-24

    Efficient enzymatic hydrolysis of lignocellulosic material remains one of the major bottlenecks to cost-effective conversion of biomass to ethanol. Improvement of glycosylhydrolases, however, is limited by existing medium-throughput screening technologies. Here, we report the first high-throughput selection for cellulase catalysts. This selection was developed by adapting chemical complementation to provide a growth assay for bond cleavage reactions. First, a URA3 counter selection was adapted to link chemical dimerizer activated gene transcription to cell death. Next, the URA3 counter selection was shown to detect cellulase activity based on cleavage of a tetrasaccharide chemical dimerizer substrate and decrease in expression of the toxic URA3 reporter. Finally, the utility of the cellulase selection was assessed by isolating cellulases with improved activity from a cellulase library created by family DNA shuffling. This application provides further evidence that chemical complementation can be readily adapted to detect different enzymatic activities for important chemical transformations for which no natural selection exists. Because of the large number of enzyme variants that selections can now test as compared to existing medium-throughput screens for cellulases, this assay has the potential to impact the discovery of improved cellulases and other glycosylhydrolases for biomass conversion from libraries of cellulases created by mutagenesis or obtained from natural biodiversity.

  11. Methods of obtaining an inert atmosphere for plutonium metal treatment installations; Modes d'obtention d'une atmosphere inerte dans les installations d'elaboration du plutonium metallique

    Energy Technology Data Exchange (ETDEWEB)

    Riolfo, R; Barbier, M

    1962-07-01

    Plutonium is a very pyrophoric metal (heat of combustion: 253 kCal/mole). The operations and manipulations involved in its treatment have thus to be carried out in an inert atmosphere. Several methods designed to eliminate the oxygen from the manipulation chamber have been tried: absorption by titanium - zirconium or copper turnings, or bubbling through potassium pyrogallate. They are not satisfactory. The reaction C + O{sub 2} -> CO{sub 2} has been chosen. Graphite is used. By this method, which is flexible and which has a negligible cost price, it is possible to absorb O{sub 2} within a wide range of concentrations (from 0.1 to 20 per cent) at a temperature 600 - 800 deg C compatible with the use of a conventional material. This report describes the trials carried out, the method selected and experimented, with the experimental details, the results obtained, and the extension of the method for a slightly different use. (authors) [French] Le plutonium est un metal tres pyrophorique (chaleur de combustion 253 kCal/mole). Les operations et manipulations qui decoulent de son elaboration doivent donc s'effectuer sous atmosphere inerte. Plusieurs methodes, dont le but etait d'eliminer l'oxygene de l'enceinte d'elaboration ont ete essayees: absorption par des copeaux de titane-zirconium, de cuivre, ou barbotage sur le pyrogallate de potasse. Elles n'ont pas donne satisfaction. La reaction C + O{sub 2} {yields} CO{sub 2} a ete retenue. On utilise le graphite. D'une tres grande souplesse d'utilisation, d'un prix de revient nul, il permet d'absorber l'oxygene dans une fourchette etendue de concentration (0,1 a 20 pour cent) a une temperature (600 a 800 degres C) compatible avec l'emploi d'un materiel classique. Cet expose decrit les essais effectues, la methode retenue et experimentee, le mode operatoire, les resultats obtenus, et l'extension de la methode a un probleme legerement different. (auteurs)

  12. Environmental high resolution electron microscopy and applications to chemical science

    OpenAIRE

    Boyes, Edward; Gai, Pratibha

    2017-01-01

    An environmental cell high resolution electron microscope (EHREM) has been developed for in situ studies of dynamic chemical reactions on the atomic scale. It allows access to metastable intermediate phases of catalysts and to sequences of reversible microstructural and chemical development associated with the activation, deactivation and poisoning of a catalyst. Materials transported through air can be restored or recreated and samples damaged, e.g. by dehydration, by the usual vacuum enviro...

  13. Foam glass obtained through high-pressure sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    2018-01-01

    Foam glasses are usually prepared through a chemical approach, that is, by mixing glass powder with foaming agents, and heating the mixture to a temperature above the softening point (106.6 Pa s) of the glass. The foaming agents release gas, enabling expansion of the sintered glass. Here, we use...... a physical foaming approach to prepare foam glass. First, closed pores filled with inert gases (He, Ar, or N2) are physically introduced into a glass body by sintering cathode ray tube (CRT) panel glass powder at high gas pressure (5‐25 MPa) at 640°C and, then cooled to room temperature. The sintered bodies...... are subjected to a second heat treatment above the glass transition temperature at atmospheric pressure. This heat treatment causes expansion of the pores due to high internal gas pressure. We found that the foaming ability strongly depends on the gas pressure applied during sintering, and on the kinetic...

  14. SiO{sub 2} coating of silver nanoparticles by photoinduced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Boies, Adam M; Girshick, Steven L [Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455 (United States); Roberts, Jeffrey T [Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455 (United States); Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane, E-mail: jtrob@umn.ed, E-mail: slg@umn.ed [Nitto Denko Technical Corporation, 501 Via Del Monte, Oceanside, CA 92058 (United States)

    2009-07-22

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO{sub 2}) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO{sub 2} precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO{sub 2} coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 {sup 0}C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10{sup 7} particles cm{sup -3}.

  15. Chemicals to enhance microalgal growth and accumulation of high-value bioproducts

    Directory of Open Access Journals (Sweden)

    Xinheng eYu

    2015-02-01

    Full Text Available Photosynthetic microalgae have attracted significant attention as they can serve as important sources for cosmetic, food and pharmaceutical products, industrial materials and even biofuel biodiesels. However, current productivity of microalga-based processes is still very low, which has restricted their scale-up application. In addition to various efforts in strain improvement and cultivation optimization, it was proposed that the productivity of microalga-based processes can also be increased using various chemicals to trigger or enhance cell growth and accumulation of bioproducts. Herein, we summarized recent progresses in applying chemical triggers or enhancers to improve cell growth and accumulation of bioproducts in algal cultures. Based on their enhancing mechanisms, these chemicals can be classified into four categories:chemicals regulating biosynthetic pathways, chemicals inducing oxidative stress responses, phytohormones and analogues regulating multiple aspects of microalgal metabolism, and chemicals directly as metabolic precursors. Taken together, the early researches demonstrated that the use of chemical stimulants could be a very effective and economical way to improve cell growth and accumulation of high-value bioproducts in large-scale cultivation of microalgae.

  16. A study of the effect of circumferential temperature variations on fuel-sheath strain in an inert atmosphere

    International Nuclear Information System (INIS)

    Ferner, J.; Rondeau, R.K.; Rosinger, H.E.

    1983-07-01

    A failure model for Zircaloy-4 fuel sheaths has been developed and used to predict the effect of circumferential temperature variations (ΔT) on fuel-sheath strain behaviour in an inert atmosphere. In addition, experimental data were generated for fuel-sheath failures in the α and (α+β)-phase regions and compared to the predictions of the model. For both the experimental data and the model predictions it was found that increasing ΔT decreases sheath strain. Most of the reduction in burst strain with increasing ΔT occurs in the first 15 K to 20 K. For high ΔT values, burst strains in the α- and (α+β)-phase regions tend to an asymptotic value in the range 5 to 20 percent, irrespective of both heating rate and circumferential temperature variation. The BURST-2 computer code was used for these calculations

  17. Effect of precursor supply on structural and morphological characteristics of fe nanomaterials synthesized via chemical vapor condensation method.

    Science.gov (United States)

    Ha, Jong-Keun; Ahn, Hyo-Jun; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo

    2012-01-01

    Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method.

  18. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    Directory of Open Access Journals (Sweden)

    Yongqi Sun

    2015-03-01

    Full Text Available Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have been exploited and performed including methane reforming, coal and biomass gasification, and direct compositional modification and utilization of slags. These methods effectively meet the challenges mentioned before and help integrate the steel industry with other industrial sectors. During the heat recovery using chemical methods, slags can act as not only heat carriers but also as catalysts and reactants, which expands the field of utilization of slags. Fuel gas production using the waste heat accounts for the main R&D trend, through which the thermal heat in the slag could be transformed into high quality chemical energy in the fuel gas. Moreover, these chemical methods should be extended to an industrial scale to realize their commercial application, which is the only way by which the substantial energy in the slags could be extracted, i.e., amounting to 16 million tons of standard coal in China.

  19. Placebo effect of an inert gel on experimentally induced leg muscle pain

    Directory of Open Access Journals (Sweden)

    James G Hopker

    2010-11-01

    Full Text Available James G Hopker1, Abigail J Foad2, Christopher J Beedie2, Damian A Coleman2, Geoffrey Leach11Centre for Sports Studies, University of Kent, Chatham, Kent, UK; 2Department of Sports Science, Tourism and Leisure, Canterbury Christ Church University, Canterbury, Kent, UKPurpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia.Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent procedures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications, and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded.Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001.Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment.Keywords: conditioning, expectation, perception, positive belief, sports therapy

  20. Large-Eddy Simulation of Chemically Reactive Pollutant Transport from a Point Source in Urban Area

    Science.gov (United States)

    Du, Tangzheng; Liu, Chun-Ho

    2013-04-01

    Most air pollutants are chemically reactive so using inert scalar as the tracer in pollutant dispersion modelling would often overlook their impact on urban inhabitants. In this study, large-eddy simulation (LES) is used to examine the plume dispersion of chemically reactive pollutants in a hypothetical atmospheric boundary layer (ABL) in neutral stratification. The irreversible chemistry mechanism of ozone (O3) titration is integrated into the LES model. Nitric oxide (NO) is emitted from an elevated point source in a rectangular spatial domain doped with O3. The LES results are compared well with the wind tunnel results available in literature. Afterwards, the LES model is applied to idealized two-dimensional (2D) street canyons of unity aspect ratio to study the behaviours of chemically reactive plume over idealized urban roughness. The relation among various time scales of reaction/turbulence and dimensionless number are analysed.

  1. 40 CFR 174.525 - E. coli B-D-glucuronidase enzyme as a plant-incorporated protectant inert ingredient; exemption...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false E. coli B-D-glucuronidase enzyme as a... E. coli B-D-glucuronidase enzyme as a plant-incorporated protectant inert ingredient; exemption from the requirement of a tolerance. Residues of E. coli B-D-glucuronidase enzyme are exempt from the...

  2. Correlation between hydrogen release and degradation of limestone concrete exposed to hot liquid sodium in inert atmosphere

    International Nuclear Information System (INIS)

    Parida, F.C.; Das, S.K.; Sharma, A.K.; Ramesh, S.S.; Somayajulu, P.A.; Kannan, S.E.

    2005-01-01

    Full text of publication follows: Concrete is used as a structural material in a Fast Breeder Reactor (FBR) plant for the construction of its foundation, containment, radiation shield and equipment support structures. An accidental leakage of hot sodium on these civil structures can bring about thermo-chemical reactions, with concrete producing hydrogen gas and causing structural degradation. The concrete damage and hydrogen generation take place concurrently due to conduction of heat from sodium into the concrete and migration of steam / moisture in counter current direction towards sodium. In a series of experiments conducted with limestone concrete for two different types of design corresponding to composition and geometry, were exposed to liquid sodium (∼2 kg) at initial temperatures varying from 180 deg. C to 500 deg. C in an inerted test vessel (Capacity = 203 L). Immersion heater was employed to heat the sodium pool on the concrete cavity during the test period in some test runs. On-line continuous measurement of pressure, temperature, hydrogen gas and oxygen gas was carried out. Pre- and post- test nondestructive testing such as colour photography, spatial profiling of ultrasonic pulse velocity and measurement of dimensions were also conducted. Solid samples were collected from sodium debris by manual core drilling machine and from concrete block by hand held electric drilling machine. These samples were subjected to chemical analysis for the determination of free and bound water along with unburnt and burnt sodium. The hydrogen generation parameters such as average and peak release rate as well as release efficiency are derived from measured test variables. These test variables include temperature, pressure and hydrogen concentration in the argon atmosphere contained in the test vessel. The concrete degradation parameters encompass percentage reduction in ultrasonic pulse velocity, depth of physical and chemical dehydration and sodium penetration. These

  3. Experimental observations of effects of inert gas on cavity formation during irradiation

    International Nuclear Information System (INIS)

    Farrell, K.

    1980-04-01

    Cavity (void) formation and swelling in non-fissile materials during neutron irradiation and charged particle bombardments are reviewed. Helium is the most important inert gas and is primarily active as a cavity nucleant. It also enhances formation of dislocation structure. Preimplantation of helium overstimulates cavity nucleation and gives a different temperature response of swelling than when helium is coimplanted during the damage process. Helium affects, and is affected by, radiation-induced phase instability. Many of these effects are explainable in terms of cavity nucleation on submicroscopic critical size gas bubbles, and on the influence of the neutral sink strength of such bubbles. Titanium and zirconium resist cavity formation when vacancy loops are present

  4. Experimental observations of effects of inert gas on cavity formation during irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, K.

    1980-04-01

    Cavity (void) formation and swelling in non-fissile materials during neutron irradiation and charged particle bombardments are reviewed. Helium is the most important inert gas and is primarily active as a cavity nucleant. It also enhances formation of dislocation structure. Preimplantation of helium overstimulates cavity nucleation and gives a different temperature response of swelling than when helium is coimplanted during the damage process. Helium affects, and is affected by, radiation-induced phase instability. Many of these effects are explainable in terms of cavity nucleation on submicroscopic critical size gas bubbles, and on the influence of the neutral sink strength of such bubbles. Titanium and zirconium resist cavity formation when vacancy loops are present.

  5. Effect of adding of the styrene-butadiene-styrene (SBS) copolymer in chemical and rheological properties of the brazilian asphalt; Efeito da adicao de SBS nas propriedades quimicas e reologicas de asfalto oriundo de petroleo brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, M.C.C.; Soares, S.A. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: mccl@dqoi.ufc.br; sas@ufc.br; Soares, J.B. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Engenharia de Transportes]. E-mail: jsoares@det.ufc.br

    2003-07-01

    Chemical and rheological characterization of the asphalt cement (AC) from the Fazenda Alegre petroleum, and the effect of adding 4.5% of the styrene-butadiene-styrene (SBS) copolymer were investigated. Structural characteristics were analyzed by infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). A structure similar to the Arabian and Venezuelan petroleum was observed. The simulated aging led to structural modification noticed by the increment in the carbonyl and sulphoxide groups. Thermogravimetry (TGA) showed that SBS did not affect the AC thermal decomposition at both inert and oxidative atmosphere. However, the differential scanning calorimetry (DSC) showed a decrease in the glass transition temperature of the material when SBS was added. The effect of SBS on the absolute viscosity revealed that SBS is not an inert additive and causes an increase in viscosity, in a nonlinear fashion. The commonly found Newtonian behavior of asphalt binders under high temperatures was also found on the SBS modified binder. Dynamic mechanical tests have shown that SBS increases the binder performance grade. (author)

  6. Nanoenergetics and High Hydrogen Content Materials for Space Propulsion

    Science.gov (United States)

    2014-01-28

    past twenty years. Ammonia borane has already been used with success to produce hydrogen for chemical lasers and fuel cells. The alternatives being...adduct solution in the presence of a titanium catalyst under an inert atmosphere. The resulting material was used to reduce complexes of gold, nickel...A. Varma, B. Legrand, C. Chauveau, and I. Gokalp, “Ignition and Combustion of Al Particles Clad by Ni”, Combust. Sci. Tech., Vol. 174, 2002, pp

  7. An in vitro lung model to assess true shunt fraction by multiple inert gas elimination.

    Directory of Open Access Journals (Sweden)

    Balamurugan Varadarajan

    Full Text Available The Multiple Inert Gas Elimination Technique, based on Micropore Membrane Inlet Mass Spectrometry, (MMIMS-MIGET has been designed as a rapid and direct method to assess the full range of ventilation-to-perfusion (V/Q ratios. MMIMS-MIGET distributions have not been assessed in an experimental setup with predefined V/Q-distributions. We aimed (I to construct a novel in vitro lung model (IVLM for the simulation of predefined V/Q distributions with five gas exchange compartments and (II to correlate shunt fractions derived from MMIMS-MIGET with preset reference shunt values of the IVLM. Five hollow-fiber membrane oxygenators switched in parallel within a closed extracorporeal oxygenation circuit were ventilated with sweep gas (V and perfused with human red cell suspension or saline (Q. Inert gas solution was infused into the perfusion circuit of the gas exchange assembly. Sweep gas flow (V was kept constant and reference shunt fractions (IVLM-S were established by bypassing one or more oxygenators with perfusate flow (Q. The derived shunt fractions (MM-S were determined using MIGET by MMIMS from the retention data. Shunt derived by MMIMS-MIGET correlated well with preset reference shunt fractions. The in vitro lung model is a convenient system for the setup of predefined true shunt fractions in validation of MMIMS-MIGET.

  8. Tracheal volume in the pupa of the Saturniid moth Hyalophora cecropia determined with inert gases.

    Science.gov (United States)

    Bridges, C R; Kestler, P; Scheid, P

    1980-06-01

    Tracheal volume (VTr) was measured in pupae of the Giant silkworm moth Hyalophora cecropia (Saturniidae, Lepidoptera, Insecta) using inert gas wash-out techniques. The animal was placed in a small vessel that was continuously ventilated (rate, V) by a gas mixture containing 20% O2 in N2; the inflowing (F1) and outflowing gas fractions (FE) of the vessel could be continuously measured by a respiratory mass spectrometer. At the onset of a spiracular constriction period, which was evidenced from the FECO2 trace, the mixture was rapidly replaced by pure Ar. At the subsequent burst, the amount of N2 emerging from the animal, MN2, was calculated from V and the difference (FE--F1)N2. VTr was calculated from MN2 and the N2 concentration in the tracheal system before constriction (assumed to equal that in the ventilating gas before replacement by Ar). Measurements were repeated with N2 and Ar replacing each other. VTr average 48 microliter . g-1 (range 39 to 59) for animals of 5.8 g average body weight (range 3.4 to 9.9), when inert gas solubility in body fluids was accounted for. Both size and stage in pupal development appear to affect VTr. These values show reasonable agreement with literature data, mostly obtained by emptying the tracheal gas space by mechanical compression.

  9. CO2 chemical valorization

    International Nuclear Information System (INIS)

    Kerlero De Rosbo, Guillaume; Rakotojaona, Loic; Bucy, Jacques de; Clodic, Denis; Roger, Anne-Cecile; El Khamlichi, Aicha; Thybaud, Nathalie; Oeser, Christian; Forti, Laurent; Gimenez, Michel; Savary, David; Amouroux, Jacques

    2014-07-01

    Facing global warming, different technological solutions exist to tackle carbon dioxide (CO 2 ) emissions. Some inevitable short term emissions can be captured so as to avoid direct emissions into the atmosphere. This CO 2 must then be managed and geological storage seems to currently be the only way of dealing with the large volumes involved. However, this solution faces major economic profitability and societal acceptance challenges. In this context, alternative pathways consisting in using CO 2 instead of storing it do exist and are generating growing interest. This study ordered by the French Environment and Energy Management Agency (ADEME), aims at taking stock of the different technologies used for the chemical conversion of CO 2 in order to have a better understanding of their development potential by 2030, of the conditions in which they could be competitive and of the main actions to be implemented in France to foster their emergence. To do this, the study was broken down into two main areas of focus: The review and characterization of the main CO 2 chemical conversion routes for the synthesis of basic chemical products, energy products and inert materials. This review includes a presentation of the main principles underpinning the studied routes, a preliminary assessment of their performances, advantages and drawbacks, a list of the main R and D projects underway, a focus on emblematic projects as well as a brief analysis of the markets for the main products produced. Based on these elements, 3 routes were selected from among the most promising by 2030 for an in-depth modelling and assessment of their energy, environmental and economic performances. The study shows that the processes modelled do have favorable CO 2 balances (from 1 to 4 t-CO 2 /t-product) and effectively constitute solutions to reduce CO 2 emissions, despite limited volumes of CO 2 in question. Moreover, the profitability of certain solutions will remain difficult to reach, even with an

  10. Application of Principal Component Analysis in Assessment of Relation Between the Parameters of Technological Quality of Wheat Grains Treated with Inert Dusts Against Rice Weevil (Sitophilus oryzae L.

    Directory of Open Access Journals (Sweden)

    Marija Bodroža-Solarov

    2011-01-01

    Full Text Available Quality parameters of several wheat grain lots (low vitreous and high vitreous grains,non-infested and infested with rice weevils, (Sitophilus oryzae L. treated with inert dusts(natural zeolite, two diatomaceous earths originating from Serbia and a commercial productProtect-It® were investigated. Principal component analysis (PCA was used to investigatethe classification of treated grain lots and to assess how attributes of technological qualitycontribute to this classification. This research showed that vitreousness (0.95 and test weight(0.93 contributed most to the first principal component whereas extensigraph area (-0.76contributed to the second component. The determined accountability of the total variabilityby the first component was around 55%, while with the second it was 18%, which meansthat those two dimensions together account for around 70% of total variability of the observedset of variables. Principal component analysis (PCA of data set was able to distinguishamong the various treatments of wheat lots. It was revealed that inert dust treatments producedifferent effects depending on the degree of endosperm vitreousness.

  11. Bacterial Adhesion to Diamond-like Carbon as Compared to Stainless Steel

    NARCIS (Netherlands)

    Soininen, Antti; Tiainen, Veli-Matti; Konttinen, Yrjo T.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

    Recent studies suggest that diamond-like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most

  12. Thermal Analysis of Solid Fuels in an Inert Atmosphere

    Science.gov (United States)

    Kijo-Kleczkowska, Agnieszka; Szumera, Magdalena; Środa, Katarzyna

    2017-12-01

    The paper takes the analysis of thermal studies of different types of fuels. It allowed diversification of fuels depending on their composition and origin. Consideration of coal, biomass and waste (coal mule, sewage sludge) as fuel is nowadays an important aspect of energy in our country. It should be emphasized that Poland power engineering is based up to 95% on coal - the primary fuel. Mining industry, forced to deliver power engineering more and better fuel, must however, use a deeper cleaning of coal. This results in a continuous increase waste in the form of mule flotation. The best method of disposing these mule is combustion and co-combustion with other fuels. On the other hand, commonly increasing awareness state of the environment and the need to reduce CO2 emissions energy industry have committed to implement alternative solutions in order to gain power, through, i.a.: development technologies use of biomass, which is one of the most promising renewable energy sources in Poland. The paper presents the results of research TG-DTA fuels made in an inert atmosphere.

  13. High temperature slagging incinerator for TRU-waste treatment

    International Nuclear Information System (INIS)

    Van De Voorde, N.; Hennart, D.; Gijbels, J.; Mergan, L.

    1984-01-01

    Since 1974 the Belgian Nuclear Study Center (SCK/CEN) at Mol, with the support of the European Communities, has developed an ''integral'' system for the treatment and the conditioning of radioactive contaminated wastes. The system converts directly, at high temperature (1500 0 C), mixtures of combustibles (paper, plastics, rubber etc.) and non-combustibles (metals, soil, sludge, concrete.) contaminated with transuranium elements as well as beta-gamma emitting isotopes, into a chemically inert and physically stable slag. More than 4000 hours of successful operation, with wide variety of simulated waste composition as well as real waste, have confirmed the safe operability of the high temperature sl'Gging incinerator and the connected installations, such as sorting cells, waste shredder, off-gas purification train, slag extraction system, remoted control, and the alpha-containment building. During the fall of 1983, a final confirmation of the performance of the installation was given by the successful accomplishment of an incineration campaign of 16 to 17 tons of simulated solid plutonium contaminated wastes

  14. Physical adsorption vs. chemical binding of undecylenic acid on porous silicon surface: a comparative study of differently functionalized materials

    Energy Technology Data Exchange (ETDEWEB)

    Salonen, J.; Lehto, V.P. [University of Turku (Finland). Department of Physics; Chirvony, V.; Matveeva, E. [Nanophotonics Technology Center, Technical University of Valencia (Spain); Pastor, E.

    2009-07-15

    To imply miscibility to porous silicon (PSi) used for biomedical purposes a number of functionalization methods are employed. In order to distinguish between a non-specific surfactant-like interaction (physical sorption) and chemical binding of unsaturated chemicals (undecylenic acid, UD) to H-terminated PSi surface we studied the two differently treated materials. Differential scanning calorimetry (DSC) and thermogravimetry (TGA), BET and FTIR measurements were performed with the PSi powder samples (n+ doped). Changes in surface area, weight loss, calorific effect and chemical composition that accompanied the thermal treatment have shown that the physisorbed UD molecules undergo a chemical process (binding) with the Si-H{sub x} surface groups at about 150 C in both, N{sub 2} inert atmosphere and in a synthetic air, oxidative atmosphere. Controlled conversion of physically sorbed molecules to the chemically attached ones is discussed with respect to methods of surface modification of PSi materials for increasing their biocompatibility. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Disposição em aterros controlados de resíduos sólidos industriais não-inertes: avaliação dos componentes tóxicos e implicações para o ambiente e para a saúde humana Non-inert industrial solid waste disposal in landfill dumps: evaluation of toxicity and implications for the environment and human health

    Directory of Open Access Journals (Sweden)

    Cristina L. S. Sisinno

    2003-04-01

    Full Text Available Para que um resíduo sólido seja disposto adequadamente, é necessário classificá-lo segundo as Normas Técnicas Brasileiras, cuja principal é a NBR 10.004. Resíduos sólidos industriais não-inertes normalmente têm sido encaminhados para disposição final em aterros controlados, que em sua maioria não operam de forma eficiente, além de estarem geralmente localizados próximos a núcleos populacionais e ecossistemas importantes. A fim de avaliar a toxicidade potencial dos resíduos produzidos em indústrias de diferentes segmentos, 21 amostras foram analisadas de acordo com as orientações descritas na NBR 10.004. Das amostras estudadas, 18 foram classificadas como resíduos não-inertes. Os principais parâmetros que contribuíram para a classificação das amostras em resíduos não-inertes foram: alumínio, ferro, manganês, fenol e surfactantes. Destes, o alumínio, o manganês e o fenol são as substâncias de maior interesse toxicológico para a saúde humana e ambiental, uma vez que podem alterar a qualidade das águas subterrâneas localizadas nas áreas de disposição de resíduos.According to Brazilian recommended technical procedures (mainly NBR 10,004, solid waste must be previously classified in order to be disposed of adequately. Non-inert industrial solid waste is being dumped in landfill areas, most of which operate inefficiently and are located near the population and important ecosystems. In order to evaluate the potential toxicity of solid waste produced by various types of industries, 21 samples were analyzed according to NBR 10,004 procedures. Of these, 18 were classified as non-inert solid waste. The main substances contributing to the classification of these samples as non-inert waste were: aluminum, iron, manganese, phenol, and surfactants. Aluminum, manganese, and phenol are the main toxicologically relevant substances for human and environmental health because they can alter the quality of groundwater

  16. The coupling of high-speed high resolution experimental data and LES through data assimilation techniques

    Science.gov (United States)

    Harris, S.; Labahn, J. W.; Frank, J. H.; Ihme, M.

    2017-11-01

    Data assimilation techniques can be integrated with time-resolved numerical simulations to improve predictions of transient phenomena. In this study, optimal interpolation and nudging are employed for assimilating high-speed high-resolution measurements obtained for an inert jet into high-fidelity large-eddy simulations. This experimental data set was chosen as it provides both high spacial and temporal resolution for the three-component velocity field in the shear layer of the jet. Our first objective is to investigate the impact that data assimilation has on the resulting flow field for this inert jet. This is accomplished by determining the region influenced by the data assimilation and corresponding effect on the instantaneous flow structures. The second objective is to determine optimal weightings for two data assimilation techniques. The third objective is to investigate how the frequency at which the data is assimilated affects the overall predictions. Graduate Research Assistant, Department of Mechanical Engineering.

  17. Leaching behaviour of bottom ash from RDF high-temperature gasification plants

    International Nuclear Information System (INIS)

    Gori, M.; Pifferi, L.; Sirini, P.

    2011-01-01

    This study investigated the physical properties, the chemical composition and the leaching behaviour of two bottom ash (BA) samples from two different refuse derived fuel high-temperature gasification plants, as a function of particle size. The X-ray diffraction patterns showed that the materials contained large amounts of glass. This aspect was also confirmed by the results of availability and ANC leaching tests. Chemical composition indicated that Fe, Mn, Cu and Cr were the most abundant metals, with a slight enrichment in the finest fractions. Suitability of samples for inert waste landfilling and reuse was evaluated through the leaching test EN 12457-2. In one sample the concentration of all metals was below the limit set by law, while limits were exceeded for Cu, Cr and Ni in the other sample, where the finest fraction showed to give the main contribution to leaching of Cu and Ni. Preliminary results of physical and geotechnical characterisation indicated the suitability of vitrified BA for reuse in the field of civil engineering. The possible application of a size separation pre-treatment in order to improve the chemical characteristics of the materials was also discussed.

  18. Chemicals in Meat Cooked at High Temperatures and Cancer Risk

    Science.gov (United States)

    ... Services Directory Cancer Prevention Overview Research Chemicals in Meat Cooked at High Temperatures and Cancer Risk On ... hydrocarbons, and how are they formed in cooked meats? What factors influence the formation of HCA and ...

  19. Cyanobacteria as a Platform for the High-Value Chemicals Production

    DEFF Research Database (Denmark)

    Wlodarczyk, Artur Jacek

    and cheap fertilizer as a medium for the cultivation of engineered cyanobacterial strains is shown. Alternative strategy to engineer Synechocystis sp. PCC 6803 as a universal platform for the sustainable production of diverse range high-value phenylpropanoids which find use as pharmaceuticals, cosmetics......Emerging problems like increasing global warming and depletion of fossil fuels bring serious concerns regarding production of food and various chemicals in the future. Clearly, there is a need for finding alternative and more sustainable ways of producing chemicals in order to satisfy increasing...... consumer demands of an ever growing population. Considering the ability to convert solar energy and carbon dioxide into biomass, cyanobacteria and microalgae have potential for becoming such alternative in the future. Biosynthesis of a great number of plant high-value secondary metabolites requires...

  20. Network synthesis and parameter optimization for vehicle suspension with inerter

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-12-01

    Full Text Available In order to design a comfortable-oriented vehicle suspension structure, the network synthesis method was utilized to transfer the problem into solving a timing robust control problem and determine the structure of “inerter–spring–damper” suspension. Bilinear Matrix Inequality was utilized to obtain the timing transfer function. Then, the transfer function of suspension system can be physically implemented by passive elements such as spring, damper, and inerter. By analyzing the sensitivity and quantum genetic algorithm, the optimized parameters of inerter–spring–damper suspension were determined. A quarter-car model was established. The performance of the inerter–spring–damper suspension was verified under random input. The simulation results manifested that the dynamic performance of the proposed suspension was enhanced in contrast with traditional suspension. The root mean square of vehicle body acceleration decreases by 18.9%. The inerter–spring–damper suspension can inhibit the vertical vibration within the frequency of 1–3 Hz effectively and enhance the performance of ride comfort significantly.

  1. Inert annealing of irradiated graphite by inductive heating

    International Nuclear Information System (INIS)

    Botzem, W.; Woerner, J.

    2001-01-01

    Fission neutrons change physical properties of graphite being used in nuclear reactors as moderator and as structural material. The understanding of these effects on an atomic model is expressed by dislocations of carbon atoms within the graphite and the thereby stored energy is known as Wigner Energy. The dismantling of the Pile 1 core may necessitate the thermal treatment of the irradiated but otherwise undamaged graphite. This heat treatment - usually called annealing - initiates the release of stored Wigner Energy in a controlled manner. This energy could otherwise give rise to an increase in temperature under certain conditions during transport or preparation for final storage. In order to prevent such an effect it is intended to anneal the major part of Pile 1 graphite before it is packed into boxes suitable for final disposal. Different heating techniques have been assessed. Inductive heating in an inert atmosphere was selected for installation in the Pile 1 Waste Processing Facility built for the treatment and packaging of the dismantled Pile 1 waste. The graphite blocks will be heated up to 250 deg. C in the annealing ovens, which results in the release of significant amount of the stored energy. External heat sources in a final repository will never heat up the storage boxes to such a temperature. (author)

  2. Fulltext PDF

    Indian Academy of Sciences (India)

    were not for nitrogen, many things would burn (react with oxy- gen) with explosive violence! It is this very property of nitrogen that makes it very special. Measuring Inertness. The chemical inertness of dinitrogen almost equaling that of inert gases is quite surprising. Inertness can be related to the reluctance to share, donate ...

  3. The effects of chemical kinetics and wall temperature on performance of porous media burners

    Science.gov (United States)

    mohammadi, Iman; Hossainpour, Siamak

    2013-06-01

    This paper reports a two-dimensional numerical prediction of premixed methane-air combustion in inert porous media burner by using of four multi-step mechanisms: GRI-3.0 mechanism, GRI-2.11 mechanism and the skeletal and 17 Species mechanisms. The effects of these models on temperature, chemical species and pollutant emissions are studied. A two-dimensional axisymmetric model for premixed methane-air combustion in porous media burner has developed. The finite volume method has used to solve the governing equations of methane-air combustion in inert porous media burner. The results indicate that the present four models have the same accuracy in predicting temperature profiles and the difference between these profiles is not more than 2 %. In addition, the Gri-3.0 mechanism shows the best prediction of NO emission in comparison with experimental data. The 17 Species mechanism shows good agreement in prediction of temperature and pollutant emissions with GRI-3.0, GRI-2.11 and the skeletal mechanisms. Also the effects of wall temperature on the gas temperature and mass fraction of species such as NO and CH4 are studied.

  4. Chemical treatment and biomimetic coating evaluating in zirconia-alumina ceramics; Avaliacao de tratamentos quimicos e recobrimento biomimetico em ceramicas de alumina-zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Amanda Abati

    2007-07-01

    Ceramic materials, as alumina and zirconia have been explored along the years as biomaterials application. The bio inert nature has been stimulating the development of new alternatives, as chemical treatments to improve the biological application of these ceramics. The biomimetic process of bio inert ceramics for coating apatite is based on soaking the implant in a simulated body fluid, SBF, with ion concentrations nearly equal to those of human blood plasma. The bioactivity of the material is related with the formation of a layer constituted of hydroxyapatite low crystalline, similar to the biological apatite. The biocompatibility associated to the structural properties of the alumina and zirconia has been stimulating the clinical use of these materials, mainly in areas of larger mechanical requests, places not recommended for bioactive hydroxyapatite, for instance. In this work samples of alumina, zirconia doped with Yttria (3% mol) and composites of alumina and zirconia doped with Yttria (3% mol) were prepared by co-precipitation method, calcinate, sintered, chemically treated with solutions of acid phosphoric and sodium hydroxide and them immersed in 1.0 M and 1.5 M SBF. The calcinate powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), gas adsorption (BET) and laser diffraction. The XRD results indicate that the samples are low crystalline. It was observed for BET that the samples present high specific surface area. The results of laser diffraction and SEM showed that the powders are agglomerates. The sintered samples were analyzed by XRD, SEM and X-ray fluorescence (XRF). The phases quantified by Rietveld method were: cubic, tetragonal and monoclinic of the zirconia, besides the phase alpha of the alumina. The chemical treatment with phosphoric acid didn't present a tendency of larger apatite formation in relation to the samples no chemically treated. The treatment with sodium hydroxide provoked accentuated transformation

  5. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  6. Experimental investigations of tungsten inert gas assisted friction stir welding of pure copper plates

    Science.gov (United States)

    Constantin, M. A.; Boșneag, A.; Nitu, E.; Iordache, M.

    2017-10-01

    Welding copper and its alloys is usually difficult to join by conventional fusion welding processes because of high thermal diffusivity of the copper, alloying elements, necessity of using a shielding gas and a clean surface. To overcome this inconvenience, Friction Stir Welding (FSW), a solid state joining process that relies on frictional heating and plastic deformation, is used as a feasible welding process. In order to achieve an increased welding speed and a reduction in tool wear, this process is assisted by another one (WIG) which generates and adds heat to the process. The aim of this paper is to identify the influence of the additional heat on the process parameters and on the welding joint properties (distribution of the temperature, hardness and roughness). The research includes two experiments for the FSW process and one experiment for tungsten inert gas assisted FSW process. The outcomes of the investigation are compared and analysed for both welding variants. Adding a supplementary heat source, the plates are preheated and are obtain some advantages such as reduced forces used in process and FSW tool wear, faster and better plasticization of the material, increased welding speed and a proper weld quality.

  7. Combustión de mezclas ricas de etano-aire en medios porosos inertes Combustion of rich ethane-air mixtures in inert porous media

    Directory of Open Access Journals (Sweden)

    Khriscia Utria S

    2013-04-01

    Full Text Available El presente trabajo tiene por objetivo analizar teórica-experimentalmente la combustión de mezclas ricas de etano-aire en medios porosos inertes (MPI para evaluar la producción de hidrógeno y gas de síntesis. Se analizan los perfiles de temperatura, las velocidades de propagación de llama y los productos principales de la combustión, como son el hidrógeno (H2 y el monóxido de carbono (CO, mediante el uso de cromatografía gaseosa, para relaciones de equivalencia en el rango de 1,0 a 2,5 y dos diámetros de esferas de alúmina que componen el medio poroso. Se simula numéricamente el proceso de combustión mediante el uso del programa PREMIX utilizando dos mecanismos de reacción, como son el GRI-MECH 1.2 y GRI-MECH 3.0. Con GRI-MECH 3.0 se obtienen resultados numéricos que predicen correctamente los resultados experimentales para todo el rango de relaciones de equivalencia con un medio poroso compuesto por esferas de alúmina de 3,5 mm. La máxima generación de hidrógeno H2 y CO presentes en los productos de combustión son de 14,3% y 18,0%, respectivamente. El porcentaje de conversión de etano en H2 (61,3% y en CO (81% muestra el potencial de este combustible como generador de gas de síntesis.This research develops the theoretical and experimental analysis of ethane-air combustion in inert porous media (IPM to evaluate hydrogen and syngas production. Temperature profiles, flame propagation rates and major combustion products such as hydrogen (H2 and carbon monoxide (CO, through gas chromatography, are analysed at a range of equivalence ratios between 1.0 and 2.5, with two different alumina sphere diameters composing the porous media. Combustion of ethane-air mixture in IPM is simulated numerically using the PREMIX program with two reaction mechanisms, such as GRI-MECH 1.2 and GRI-MECH 3.0. GRI-MECH 3.0 numerical results predict correctly experimental results for a porous media with 3.5 mm alumina spheres along the range of

  8. A High-throughput Selection for Cellulase Catalysts Using Chemical Complementation

    Science.gov (United States)

    Peralta-Yahya, Pamela; Carter, Brian T.; Lin, Hening; Tao, Haiyan; Cornish, Virginia W.

    2010-01-01

    Efficient enzymatic hydrolysis of lignocellulosic material remains one of the major bottlenecks to cost-effective conversion of biomass to ethanol. Improvement of glycosylhydrolases however is limited by existing medium-throughput screening technologies. Here, we report the first high-throughput selection for cellulase catalysts. This selection was developed by adapting chemical complementation to provide a growth assay for bond cleavage reactions. First, a URA3 counter selection was adapted to link chemical dimerizer activated gene transcription to cell death. Next, the URA3 counter selection was shown to detect cellulase activity based on cleavage of a tetrasaccharide chemical dimerizer substrate and decrease in expression of the toxic URA3 reporter. Finally, the utility of the cellulase selection was assessed by isolating cellulases with improved activity from a cellulase library created by family DNA shuffling. This application provides further evidence that chemical complementation can be readily adapted to detect different enzymatic activities for important chemical transformations for which no natural selection exists. Due to the large number of enzyme variants selections can test compared to existing medium-throughput screens for cellulases, this assay has the potential to impact the discovery of improved cellulases and other glycosylhydrolases for biomass conversion from libraries of cellulases created by mutagenesis or obtained from natural biodiversity. PMID:19053460

  9. Medium optimization for nuclease P1 production by Penicillium citrinum in solid-state fermentation using polyurethane foam as inert carrier

    NARCIS (Netherlands)

    Zhu, Y.; Knol, W.; Smits, J.P.; Bol, J.

    1996-01-01

    A solid-state fermentation system, using polyurethane foam as an inert carrier, was used for the production of nuclease P1 by Penicillium citrinum. Optimization of nuclease P1 production was carried out using a synthetic liquid medium. After a two-step medium optimization using a fractional

  10. Thermal and Chemical Characterization of Non-Metallic Materials Using Coupled Thermogravimetric Analysis and Infrared Spectroscopy

    Science.gov (United States)

    Huff, Timothy L.

    2002-01-01

    Thermogravimetric analysis (TGA) is widely employed in the thermal characterization of non-metallic materials, yielding valuable information on decomposition characteristics of a sample over a wide temperature range. However, a potential wealth of chemical information is lost during the process, with the evolving gases generated during thermal decomposition escaping through the exhaust line. Fourier Transform-Infrared spectroscopy (FT-IR) is a powerful analytical technique for determining many chemical constituents while in any material state, in this application, the gas phase. By linking these two techniques, evolving gases generated during the TGA process are directed into an appropriately equipped infrared spectrometer for chemical speciation. Consequently, both thermal decomposition and chemical characterization of a material may be obtained in a single sample run. In practice, a heated transfer line is employed to connect the two instruments while a purge gas stream directs the evolving gases into the FT-IR. The purge gas can be either high purity air or an inert gas such as nitrogen to allow oxidative and pyrolytic processes to be examined, respectively. The FT-IR data is collected realtime, allowing continuous monitoring of chemical compositional changes over the course of thermal decomposition. Using this coupled technique, an array of diverse materials has been examined, including composites, plastics, rubber, fiberglass epoxy resins, polycarbonates, silicones, lubricants and fluorocarbon materials. The benefit of combining these two methodologies is of particular importance in the aerospace community, where newly developing materials have little available data with which to refer. By providing both thermal and chemical data simultaneously, a more definitive and comprehensive characterization of the material is possible. Additionally, this procedure has been found to be a viable screening technique for certain materials, with the generated data useful in

  11. The smoke ion source: A device for the generation of cluster ions via inert gas condensation

    International Nuclear Information System (INIS)

    McHugh, K.M.; Sarkas, H.W.; Eaton, J.G.; Bowen, K.H.; Westgate, C.R.

    1989-01-01

    We report the development of an ion source for generating intense, continuous beams of both positive and negative cluster ions. This device is the result of the marriage of the inert gas condensation method with techniques for injecting electrons directly into expanding jets. In the preliminary studies described here, we have observed cluster ion size distributions ranging from n=1-400 for Pb n + and Pb n - and from n=12-5700 for Li n - . (orig.)

  12. Sn and Cu oxide nanoparticles deposited on TiO{sub 2} nanoflower 3D substrates by Inert Gas Condensation technique

    Energy Technology Data Exchange (ETDEWEB)

    Kusior, A., E-mail: akusior@agh.edu.pl [Faculty of Materials Science and Ceramics, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Kollbek, K. [Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Kowalski, K. [Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Borysiewicz, M. [Institute of Electron Technology, al. Lotnikow 32/46, 02-668 Warszawa (Poland); Wojciechowski, T. [Institute of Physics Polish Academy of Science, al. Lotnikow 32/46, 02-668 Warszawa (Poland); Adamczyk, A.; Trenczek-Zajac, A.; Radecka, M. [Faculty of Materials Science and Ceramics, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Zakrzewska, K. [Faculty of Computer Science, Electronics and Telecommunications, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland)

    2016-09-01

    Graphical abstract: - Highlights: • Inert Gas Condensation method yields non-agglomerated nanoparticles. • The growth of nanoparticles is controllable at the level of deposition. • Electrical conductivity increases with respect to pure nanostructured TiO{sub 2}. - Abstract: Sn and Cu oxide nanoparticles were deposited by Inert Gas Condensation (IGC) technique combined with dc magnetron sputtering onto nanoflower TiO{sub 2} 3D substrates obtained in the oxidation process of Ti-foil in 30% H{sub 2}O{sub 2}. Sputtering parameters such as insertion length and Ar/He flow rates were optimized taking into account the nanostructure morphology. Comparative studies with hydrothermal method were carried out. Surface properties of the synthesized nanomaterials were studied by Scanning Electron Microscopy, SEM, Atomic Force Microscopy, AFM, and X-ray Photoelectron Spectroscopy, XPS. X-ray diffraction, XRD and Raman spectroscopy were performed in order to determine phase composition. Impedance spectroscopy demonstrated the influence of nanoparticles on the electrical conductivity.

  13. Biodegradability oriented treatability studies on high strength segregated wastewater of a woolen textile dyeing plant.

    Science.gov (United States)

    Baban, Ahmet; Yediler, Ayfer; Ciliz, NilgunKiran; Kettrup, Antonius

    2004-11-01

    Textile dyeing and finishing industry involves considerable amount of water usage as well as polluted and highly colored wastewater discharges. Biological treatability by means of mineralization, nitrification and denitrification of high strength woolen textile dye bathes, first- and second-rinses is presented. COD fractionation study was carried out and kinetic parameters were determined. Biodegradability of organic compounds in highly loaded composite wastewater after segregation and the effluent of applied biological treatment of high strength composite wastewater were measured by determining oxygen consumption rates. The results were used in terms of assessing an alternative method for inert COD fractionation. The study implied that about 80% soluble COD, 50% color and 75% toxicity reduction were possible by single sludge biological processes. Sixteen per cent of total COD was found to be initially inert. Inert fraction was increased to 22% by production of soluble and particulate microbial products through biological treatment. copyright 2004 Elsevier Ltd.

  14. The Influences of Time and Velocity of Inert Gas on the Quality of theProcessing Product of Graphite Matrix on the Baking Step

    International Nuclear Information System (INIS)

    Imam-Dahroni; Dwi-Herwidhi; NS, Kasilani

    2000-01-01

    The research of the synthesis of matrix graphite on the step of bakingprocess was conducted, by focusing on the influence of time and velocityvariables of the inert gas. The investigation on baking times ranging from 5minutes to 55 minutes and by varying the velocity of inert gas from 0.30l/minute to 3.60 l/minute, resulted the product of different matrix.Optimizing at the time of operation and the flow rate of argon gas indicatedthat the baking time for 30 minutes and by the flow rate of argon gas of 2.60l/minute resulted best matrix graphite that has a hardness value of 11kg/mm 2 of hardness and the ductility of 1800 Newton. (author)

  15. Chemically vapor-deposited tungsten: its high temperature strength and ductility

    International Nuclear Information System (INIS)

    Bryant, W.A.

    1977-01-01

    The high temperature tensile ductility (as measured by total elongation normal to the growth direction) of chemically vapor-deposited tungsten was found to be significantly greater than previously reported. A correlation was found between ductility and void content. However, voids were found to have essentially no effect on the high temperature strength of this material, which is considerably weaker than powder metallurgy tungsten. (Auth.)

  16. Investigation of the Hall MHD channel operating with the ionized instable plasma of inert gases

    International Nuclear Information System (INIS)

    Vasi'leva, R.V.; D'yakova, E.A.; Erofeev, A.V.; Zuev, A.D.; Lapushkina, T.A.; Markhotok, A.A.

    1997-01-01

    Possibility of applying ionization-instable plasma of pure inert gases as perspective working substance for closed-cycle MHD generators is studied. The experiment was produced in the model of the disk Hall MHD channel. The ionized gas flux was produced in a shock tube. Xenon was used as a working substance. Gas pressure, flux velocity, electron concentration and temperature, azimuthal current density, potential distribution in the channel and near-electrode voltage drop values were measured in the experiment. Volt-ampere characteristics were taken by various indices of magnetic field and load resistance

  17. Risk-based high-throughput chemical screening and prioritization using exposure models and in vitro bioactivity assays

    DEFF Research Database (Denmark)

    Shin, Hyeong-Moo; Ernstoff, Alexi; Arnot, Jon

    2015-01-01

    We present a risk-based high-throughput screening (HTS) method to identify chemicals for potential health concerns or for which additional information is needed. The method is applied to 180 organic chemicals as a case study. We first obtain information on how the chemical is used and identify....../oral contact, or dermal exposure. The method provides high-throughput estimates of exposure and important input for decision makers to identify chemicals of concern for further evaluation with additional information or more refined models....

  18. Investigation of the Thermal Stability of Nd(x)Sc(y)Zr(1-x-y)O(2-δ) Materials Proposed for Inert Matrix Fuel Applications.

    Science.gov (United States)

    Hayes, John R; Grosvenor, Andrew P; Saoudi, Mouna

    2016-02-01

    Inert matrix fuels (IMF) consist of transuranic elements (i.e., Pu, Am, Np, Cm) embedded in a neutron transparent (inert) matrix and can be used to "burn up" (transmute) these elements in current or Generation IV nuclear reactors. Yttria-stabilized zirconia has been extensively studied for IMF applications, but the low thermal conductivity of this material limits its usefulness. Other elements can be used to stabilize the cubic zirconia structure, and the thermal conductivity of the fuel can be increased through the use of a lighter stabilizing element. To this end, a series of Nd(x)Sc(y)Zr(1-x-y)O(2-δ) materials has been synthesized via a co-precipitation reaction and characterized by multiple techniques (Nd was used as a surrogate for Am). The long-range and local structures of these materials were studied using powder X-ray diffraction, scanning electron microscopy, and X-ray absorption spectroscopy. Additionally, the stability of these materials over a range of temperatures has been studied by annealing the materials at 1100 and 1400 °C. It was shown that the Nd(x)Sc(y)Zr(1-x-y)O(2-δ) materials maintained a single cubic phase upon annealing at high temperatures only when both Nd and Sc were present with y ≥ 0.10 and x + y > 0.15.

  19. Genetic and chemical diversity of high mucilaginous plants of Sida complex by ISSR markers and chemical fingerprinting.

    Science.gov (United States)

    Thul, Sanjog T; Srivastava, Ankit K; Singh, Subhash C; Shanker, Karuna

    2011-09-01

    A method was developed based on multiple approaches wherein DNA and chemical analysis was carried out toward differentiation of important species of Sida complex that is being used for commercial preparation. Isolated DNA samples were successfully performed through PCR amplification using ISSR markers and degree of genetic diversity among the different species of Sida is compared with that of chemical diversity. For genetic fingerprint investigation, selected 10 ISSR primers generating reproducible banding patterns were used. Among the total of 63 amplicons, 62 were recorded as polymorphic, genetic similarity index deduced from ISSR profiles ranged from 12 to 51%. Based on similarity index, S. acuta and S. rhombifolia found to be most similar (51%). High number of species-specific bands played pivotal role to delineate species at genetic level. Investigation based on HPTLC fingerprints analysis revealed 23 bands representing to characteristic chemicals and similarity index ranged from 73 to 91%. Prominent distinguishable bands were observed only in S. acuta, while S. cordifolia and S. rhombifolia shared most bands making them difficult to identify on chemical fingerprint basis. This report summarizes the genotypic and chemotypic diversity and the use of profiles for authentication of species of Sida complex.

  20. Development of an oxygen carrier nanoemulsion for organ preservation

    CSIR Research Space (South Africa)

    Barnard, A

    2010-08-31

    Full Text Available high levels of chemical stability and biological inertness which makes them suitable for biological use1,2. Perfluorooctyl bromide (PFOB) is the particular PFC used in the CSIR oxygen carrier emulsion1,2....

  1. High Fidelity Raman Chemical Imaging of Materials

    Science.gov (United States)

    Bobba, Venkata Nagamalli Koteswara Rao

    The development of high fidelity Raman imaging systems is important for a number of application areas including material science, bio-imaging, bioscience and healthcare, pharmaceutical analysis, and semiconductor characterization. The use of Raman imaging as a characterization tool for detecting the amorphous and crystalline regions in the biopolymer poly-L-lactic acid (PLLA) is the precis of my thesis. In the first chapter, a brief insight about the basics of Raman spectroscopy, Raman chemical imaging, Raman mapping, and Raman imaging techniques has been provided. The second chapter contains details about the successful development of tailored sample of PLLA. Biodegradable polymers are used in areas of tissue engineering, agriculture, packaging, and in medical field for drug delivery, implant devices, and surgical sutures. Detailed information about the sample preparation and characterization of these cold-drawn PLLA polymer substrates has been provided. Wide-field Raman hyperspectral imaging using an acousto-optic tunable filter (AOTF) was demonstrated in the early 1990s. The AOTF contributed challenges such as image walk, distortion, and image blur. A wide-field AOTF Raman imaging system has been developed as part of my research and methods to overcome some of the challenges in performing AOTF wide-field Raman imaging are discussed in the third chapter. This imaging system has been used for studying the crystalline and amorphous regions on the cold-drawn sample of PLLA. Of all the different modalities that are available for performing Raman imaging, Raman point-mapping is the most extensively used method. The ease of obtaining the Raman hyperspectral cube dataset with a high spectral and spatial resolution is the main motive of performing this technique. As a part of my research, I have constructed a Raman point-mapping system and used it for obtaining Raman hyperspectral image data of various minerals, pharmaceuticals, and polymers. Chapter four offers

  2. Numerical modelling of inert gas bubble rising in liquid metal pool

    International Nuclear Information System (INIS)

    Pradeep, Arjun; Sharma, Anil Kumar; Ponraju, D.; Nashine, B K.

    2016-01-01

    Two-phase flow finds several applications in safe operation of Sodium-cooled Fast Reactor (SFR). Numerical modelling of bubble rise dynamics in liquid metal pool of SFR is essential for the evaluation of residence time and shape changes, which are of utmost importance for simulating associated heat and mass transfer processes involved in reactor safety. A numerical model has been developed based on OpenFOAM for the evaluation of two-dimensional inert gas bubble rise dynamics in stagnant liquid metal pool. The governing model equations are discretized and solved using the Volume of Fluid based solver available in OpenFOAM with appropriate initial and boundary conditions. The model has been validated with available numerical benchmark results for laminar transient two-phase flow. The model has been used to evaluate velocity and rise trajectory of argon gas bubble with different diameters through a pool of liquid sodium. (author)

  3. The high pH chemical and radiation compatibility of various liner materials

    International Nuclear Information System (INIS)

    Whyatt, G.A.; Farnsworth, R.K.

    1990-01-01

    This paper reports on a flexible membrane liner that has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90 degrees C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault. The acceptance criteria for judging the compatibility of the liner with radiation would be different that those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates

  4. The high pH chemical and radiation compatibility of various liner materials

    International Nuclear Information System (INIS)

    Whyatt, G.; Farnsworth, R.

    1990-01-01

    A flexible membrane liner has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90 degrees C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault. The acceptance criteria for judging the compatibility of the liner with radiation should be different than those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates

  5. A High Power Solar Electric Propulsion - Chemical Mission for Human Exploration of Mars

    Science.gov (United States)

    Burke, Laura M.; Martini, Michael C.; Oleson, Steven R.

    2014-01-01

    Recently Solar Electric Propulsion (SEP) as a main propulsion system has been investigated as an option to support manned space missions to near-Earth destinations for the NASA Gateway spacecraft. High efficiency SEP systems are able to reduce the amount of propellant long duration chemical missions require, ultimately reducing the required mass delivered to Low Earth Orbit (LEO) by a launch vehicle. However, for long duration interplanetary Mars missions, using SEP as the sole propulsion source alone may not be feasible due to the long trip times to reach and insert into the destination orbit. By combining an SEP propulsion system with a chemical propulsion system the mission is able to utilize the high-efficiency SEP for sustained vehicle acceleration and deceleration in heliocentric space and the chemical system for orbit insertion maneuvers and trans-earth injection, eliminating the need for long duration spirals. By capturing chemically instead of with low-thrust SEP, Mars stay time increases by nearly 200 days. Additionally, the size the of chemical propulsion system can be significantly reduced from that of a standard Mars mission because the SEP system greatly decreases the Mars arrival and departure hyperbolic excess velocities (V(sub infinity)).

  6. High-risk facilities. Emergency management in nuclear, chemical and hazardous waste facilities

    International Nuclear Information System (INIS)

    Kloepfer, Michael

    2012-01-01

    The book on emergency management in high-risk facilities covers the following topics: Change in the nuclear policy, risk management of high-risk facilities as a constitutional problem - emergency management in nuclear facilities, operational mechanisms of risk control in nuclear facilities, regulatory surveillance responsibilities for nuclear facilities, operational mechanism of the risk control in chemical plants, regulatory surveillance responsibilities for chemical facilities, operational mechanisms of the risk control in hazardous waste facilities, regulatory surveillance responsibilities for hazardous waste facilities, civil law consequences in case of accidents in high-risk facilities, criminal prosecution in case of accidents in high-risk facilities, safety margins as site risk for emission protection facilities, national emergency management - strategic emergency management structures, warning and self-protection of the public in case of CBRN hazards including aspects of the psych-social emergency management.

  7. Mining Chemical Activity Status from High-Throughput Screening Assays

    KAUST Repository

    Soufan, Othman; Ba Alawi, Wail; Afeef, Moataz A.; Essack, Magbubah; Rodionov, Valentin; Kalnis, Panos; Bajic, Vladimir B.

    2015-01-01

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare.

  8. Mining Chemical Activity Status from High-Throughput Screening Assays

    KAUST Repository

    Soufan, Othman

    2015-12-14

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare.

  9. Burnup simulations and spent fuel characteristics of ZrO{sub 2} based inert matrix fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, E.A. [Department of Mechanical Engineering, University of Texas, Austin, TX (United States); Deinert, M.R. [Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY (United States)]. E-mail: mrd6@cornell.edu; Herring, S.T. [Idaho National Laboratory, Idaho Falls, ID (United States); Cady, K.B. [Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY (United States)

    2007-03-31

    Reducing the inventory of long lived isotopes that are contained in spent nuclear fuel is essential for maximizing repository capacity and extending the lifetime of related storage. Because of their non-fertile matrices, inert matrix fuels (IMF's) could be an ideal vehicle for using light-water reactors to help decrease the inventory of plutonium and other transuranics (neptunium, americium, curium) that are contained within spent uranium oxide fuel (UOX). Quantifying the characteristics of spent IMF is therefore of fundamental importance to determining its effect on repository design and capacity. We consider six ZrO{sub 2} based IMF formulations with different transuranic loadings in a 1-8 IMF to UOX pin-cell arrangement. Burnup calculations are performed using a collision probability model where transport of neutrons through space is modeled using fuel to moderator transport and escape probabilities. The lethargy dependent neutron flux is treated with a high resolution multigroup thermalization method. The results of the reactor physics model are compared to a benchmark case performed with Montebruns and indicate that the approach yields reliable results applicable to high-level analyses of spent fuel isotopics. The data generated show that a fourfold reduction in the radiological and integrated thermal output is achievable in single recycle using IMF, as compared to direct disposal of an energy equivalent spent UOX.

  10. Discovery of a Chemical Modification by Citric Acid in a Recombinant Monoclonal Antibody

    Science.gov (United States)

    2015-01-01

    Recombinant therapeutic monoclonal antibodies exhibit a high degree of heterogeneity that can arise from various post-translational modifications. The formulation for a protein product is to maintain a specific pH and to minimize further modifications. Generally Recognized as Safe (GRAS), citric acid is commonly used for formulation to maintain a pH at a range between 3 and 6 and is generally considered chemically inert. However, as we reported herein, citric acid covalently modified a recombinant monoclonal antibody (IgG1) in a phosphate/citrate-buffered formulation at pH 5.2 and led to the formation of so-called “acidic species” that showed mass increases of 174 and 156 Da, respectively. Peptide mapping revealed that the modification occurred at the N-terminus of the light chain. Three additional antibodies also showed the same modification but displayed different susceptibilities of the N-termini of the light chain, heavy chain, or both. Thus, ostensibly unreactive excipients under certain conditions may increase heterogeneity and acidic species in formulated recombinant monoclonal antibodies. By analogy, other molecules (e.g., succinic acid) with two or more carboxylic acid groups and capable of forming an anhydride may exhibit similar reactivities. Altogether, our findings again reminded us that it is prudent to consider formulations as a potential source for chemical modifications and product heterogeneity. PMID:25136741

  11. Low-temperature thermal expansion of pure and inert gas-doped fullerite C sub 6 sub 0

    CERN Document Server

    Aleksandrovskii, A N; Eselson, V B; Gavrilko, V G; Manzhelii, V G; Udovidchenko, B G; Bakai, A S; Gadd, G E; Moricca, S; Sundqvist, B

    2003-01-01

    The low temperature (2-24 K) thermal expansion of pure (single-crystal and polycrystalline) C sub 6 sub 0 and polycrystalline C sub 6 sub 0 intercalated with He, Ne, Ar, and Kr has been investigated using the high-resolution capacitance dilatometer. The investigation of the time dependence of the sample length variations DELTA L(t) on heating by DELTA T shows that the thermal expansion is determined by the sum of positive and negative contributions, which have different relaxation times. The negative thermal expansion usually prevails at helium temperatures. The positive expansion is connected with the phonon thermalization of the system. The negative expansion is caused by reorientation of the C sub 6 sub 0 molecules. It is assumed that the reorientation is of a quantum character. The inert gas impurities affect the reorientation of the C6 sub sub 0 molecules very strongly, especially at liquid helium temperatures. A temperature hysteresis of the thermal expansion coefficient of Kr- and He-C sub 6 sub 0 solu...

  12. Exploring the Inert Doublet Model through the dijet plus missing transverse energy channel at the LHC

    Directory of Open Access Journals (Sweden)

    P. Poulose

    2017-02-01

    Full Text Available In this study of the Inert Doublet Model (IDM, we propose that the dijet + missing transverse energy channel at the Large Hadron Collider (LHC will be an effective way of searching for the scalar particles of the IDM. This channel receives contributions from gauge boson fusion, and t-channel production, along with contributions from H+ associated production. We perform the analysis including study of the Standard Model (SM background with assumed systematic uncertainty, and optimise the selection criteria employing suitable cuts on the kinematic variables to maximise the signal significance. We find that with high luminosity option of the LHC, this channel has the potential to probe the IDM in the mass range of up to about 400 GeV, which is not accessible through other leptonic channels. In a scenario with light dark matter of mass about 65 GeV, charged Higgs in the mass range of around 200 GeV provides the best possibility with a signal significance of about 2σ at an integrated luminosity of about 3000 fb−1.

  13. CHEMICAL INTERACTIONS TO CLEANUP HIGHLY POLLUTED AUTOMOBILE SERVICE STATION WASTEWATER BY BIOADSORPTION-COAGULATION-FLOCCULATION

    Directory of Open Access Journals (Sweden)

    Carlos Banchon

    2017-01-01

    Full Text Available The present study addresses an ecofriendly solution to treat automobile service stations effluents with high concentrations of oily substances, surfactants, organic matter and heavy metals. Bioadsorption using sawdust from pine trees, sugar cane bagasse and coconut coir without any chemical modification removed colloidal contamination up to 70%. Polyaluminium chloride, ferric chloride and polyacrylamide were applied to remove dissolved and colloidal pollutants under saline conditions without change of initial pH. Both bioadsorption and coagulation-flocculation removed up to 97.8% of BOD, COD, surfactants and heavy metals at a saline concentration of 1.5% NaCl. The increase of ionic strength promoted a high sludge index and a representative cost saving in chemicals consumption of almost 70%. High levels of pollution removal with the minimal use of chemicals is herein presented.

  14. Sources of toxicity and exposure information for identifying chemicals of high concern to children

    International Nuclear Information System (INIS)

    Stone, Alex; Delistraty, Damon

    2010-01-01

    Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of chemicals of concern was then identified from authoritative sources, based on their potential exposure to children. Exposure potential was evaluated by identifying chemicals detected in biomonitoring studies (i.e., human tissues), as well as those present in residential exposure media (e.g., indoor air, house dust, drinking water, consumer products). Accordingly, CHCCs were defined as HPCs that also appear in biomonitoring studies or relevant exposure media. For chemicals with unique Chemical Abstracts Service (CAS) numbers, we identified 2044 HPCs and 2219 chemicals with potential exposure to children, resulting in 476 CHCCs. The process of chemical identification is dynamic, so that chemicals may be added or subtracted as new information becomes available. Although beyond the scope of this paper, the 476 CHCCs will be prioritized in a more detailed assessment, based on the strength and weight of evidence of toxicity and exposure data. Our approach was developed to be flexible which allows the addition or removal of specific sources of toxicity or exposure information, as well as transparent to allow clear identification of inputs. Although the methodology was

  15. Steam generators secondary side chemical cleaning at Point Lepreau using the Siemen's high temperature process

    International Nuclear Information System (INIS)

    Verma, K.; MacNeil, C.; Odar, S.

    1996-01-01

    The secondary sides of all four steam generators at the Point Lepreau Nuclear Generating Stations were cleaned during the 1995 annual outage run-down using the Siemens high temperature chemical cleaning process. Traditionally all secondary side chemical cleaning exercises in CANDU as well as the other nuclear power stations in North America have been conducted using a process developed in conjunction with the Electric Power Research Institute (EPRI). The Siemens high temperature process was applied for the first time in North America at the Point Lepreau Nuclear Generating Station (PLGS). The paper discusses experiences related to the pre and post award chemical cleaning activities, chemical cleaning application, post cleaning inspection results and waste handling activities. (author)

  16. Development of high temperature, radiation hard detectors based on diamond

    Energy Technology Data Exchange (ETDEWEB)

    Metcalfe, Alex, E-mail: Alex.Metcalfe@brunel.ac.uk [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Fern, George R. [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Hobson, Peter R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Ireland, Terry; Salimian, Ali; Silver, Jack [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Smith, David R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Lefeuvre, Gwenaelle [Micron Semiconductor Ltd., Lancing BN15 8 SJ (United Kingdom); Saenger, Richard [Schlumberger Limited, 91240 Clamart (France)

    2017-02-11

    Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the {sup 12}C(n,α){sup 9}Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response. - Highlights: • Radiation sensors using diamond as the sensitive volume have been constructed. • Functionality of these sensors with minimal degradation has been confirmed at 100 °C. • Sensitisation to thermal neutrons by addition of conversion layers has been modelled. • Modelling suggests 4× efficiency improvements from 3d converter-substrate interfaces.

  17. Thermodynamic, Transport and Chemical Properties of Reference JP-8

    Science.gov (United States)

    2006-06-01

    external diameter, 0.18 cm internal diameter) that are sealed on one end with a stainless steel plug welded by a clean tungsten-inert-gas ( TIG ) 15...tubing with an internal diameter of 0.02 cm, also TIG welded to the cell. Each cell and valve is capable of withstanding a pressure in excess of 105... process . Each cell is connected to a high-pressure high-temperature valve at the other end with a short length of 0.16 cm diameter 316 stainless steel

  18. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  19. Opinion of the Scientific Panel on Contaminants in the Food chain on perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and their salts

    NARCIS (Netherlands)

    Benford, D.; de Boer, J.; Carere, A.; di Domenico, A.; Johansson, N.; Schrenk, D.; Schoeters, G.; de Voogt, P.; Dellatte, E.

    2008-01-01

    Perfluoroalkylated substances (PFAS) is the collective name for a vast group of fluorinated compounds, including oligomers and polymers, which consist of neutral and anionic surface active compounds with high thermal, chemical and biological inertness. Perfluorinated compounds are generally

  20. Experimental study of the thermal conductivity coefficients of Cesium and Mercury vapours and inert gases

    International Nuclear Information System (INIS)

    Zarkova, L.P.

    1976-01-01

    A general-purpose experimental setup is made to measure thermal conductivity coefficients lambda of inert gases and metal vapours in the range 1000-2500 K by means of the differential method. The setup can also be used to measure lambda of plasmas and reacting gases as well as the dependence of lambda on magnetic fields. A simple and reliable procedure to determine the filament temperature using values of the measured current and wire diameter is suggested. The influence of different factors such as the temperature jump at the boundary gas-filament, convective heat transfer, thermal expansion, excentricity and cold ends of filament on the measured values of the thermal conductivity is considered in details. A formula is deduced to calculate the temperature jump correction taking into account the dependence of the mean free path on the temperature. Expressions are also given to calculate the corrections for thermal expansion, eccentricity and cold ends of the filament. Thermal conductivity coefficients of inert gases are measured to check the method: Ne in the range 1100-2200 K, Ar in the range 1000-2200 K, Kr in the range 1300-2300 K and Xe in the range 1100-2200 K. The data for Ne and Xe in the range 1500 to 2200 K and for Kr at T=2000-2300 K are original. The thermal conductivity coefficient of monoatomic mercury vapour is measured in the range 1000-2300 K with 3% error. The thermal conductivity coefficient of monoatomic cesium vapour is also measured in the range 1000-1600 K with 4% error. (I.P.)

  1. Fabrication and characterization of dysprosia and alumina based inert matrix neutron absorbers

    International Nuclear Information System (INIS)

    D Ovidio, C.; Oliber, E.; Leiva, S.; Malachevsky, M. T; Taboada, H

    2009-01-01

    Among the elements of the lanthanides series, dysprosium has interesting nuclear properties. Its high thermal neutron absorption cross-section makes it a good neutron absorber. The best ceramic compound apt for nuclear use is its oxide, the disprosia (Dy 2 O 3 ). In order to fabricate neutron absorbers diluted in an inert matrix, it is relevant to study the preparation of a ceramic compound based on alumina (Al 2 O 3 ) and disprosia. In this work, we characterize a particular composition (44,5wt% Dy 2 O 3 , 55,5wt% Al 2 O 3 ) by determining the geometrical density, microstructure and phase formation. The chosen composition corresponds to the lowest temperature eutectic of the alumina-disprosia system, allowing the sintering to proceed at 1700 oC in air. Comparing the data of the green and sinterized pellets, the relative shrinking is of about 17 %, in the same proportion both for diameter and length. The corresponding volumetric reduction is of about 43 %, indicating an increase of the relative geometric density of ∼ 70 %. X-ray diffraction analysis shows the existence of two phases corresponding to the lower eutectic: Dy 3 Al 5 O 1 2 and Al 2 O 3 . The calculated theoretical density is ∼ 5.2 g/cm3. Consequently, the relative density of the pellets is 92 %, indicating the feasibility for the fabrication of the proposed material. In a near future, samples will be irradiated to evaluate their behavior for nuclear use. [es

  2. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    Science.gov (United States)

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  3. Production of inert gas for substitution of a part of the cushion gas trapped in an aquifer underground storage reservoir

    International Nuclear Information System (INIS)

    Berger, L.; Arnoult, J.P.

    1990-01-01

    In a natural gas storage reservoir operating over the different seasons, a varying fraction of the injected gas, the cushion gas, remains permanently trapped. This cushion gas may represent more than half the total gas volume, and more than 50% of the initial investment costs for the storage facility. Studies conducted by Gaz de France, backed up by experience acquired over the years, have shown that at least 20% of the cushion gas could be replaced by a less expensive inert gas. Nitrogen, carbon dioxide, or a mixture of the two, satisfy the specifications required for this inert gas. Two main production methods exist: recovery of natural gas combustion products (mixture of 88% N 2 and 12% Co 2 ) and physical separation of air components (more or less pure N 2 , depending on industrial conditions). For the specific needs of Gaz de France, the means of production must be suited to its programme of partial cushion gas substitution. The equipment must satisfy requirements of autonomy, operating flexibility and mobility. Gaz de France has tested two units for recovery of natural gas combustion products. In the first unit, the inert gas is produced in a combustion chamber, treated in a catalytic reactor to reduce nitrogen oxide content and then compressed by gas engine driven compressors. In the second unit, the exhaust gases of the compressor gas engines are collected, treated to eliminate nitrogen oxides and then compressed. The energy balance is improved. A PSA method nitrogen production unit by selective absorption of nitrogen in the air, will be put into service in 1989. The specific features of these two methods and the reasons for choosing them will be reviewed. (author). 1 fig

  4. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    1993-03-01

    The Sub-Committee on Chemical Analysis of Graphite was organized in April 1989, under the Committee on Chemical Analysis of Nuclear Fuels and Reactor Materials, JAERI. The Sub-Committee carried out collaborative analyses among eleven participating laboratories for the certification of the Certified Reference Materials (CRMs), JAERI-G5 and G6, after developing and evaluating analytical methods during the period of September 1989 to March 1992. The certified values were given for ash, boron and silicon in the CRM based on the collaborative analysis. The values for ten elements (Al, Ca, Cr, Fe, Mg, Mo, Ni, Sr, Ti, V) were not certified, but given for information. Preparation, homogeneity testing and chemical analyses for certification of reference materials were described in this paper. (author) 52 refs

  5. Chemical interaction silicon nitride ceramics and iron alloys

    Directory of Open Access Journals (Sweden)

    Oliveira, F. J.

    2000-12-01

    Full Text Available Metal/ceramic diffusion experiments are helpful to study bonding mechanisms or the effect of metal composition on the chemical wear of ceramic cutting tools. The reaction kinetics of Fe alloys/Si3 N4 ceramic diffusion couples was investigated in the temperature range 1050ºC-1250ºC, for 0.5h to 80h, under inert atmosphere. Optical microscopy, SEM and EPMA were carried out in cross sections of the reacted pairs. Si3N4 decomposes into Si and N that dissolve and diffuse through the metal. Both the diffusion zone on the metal side and the reaction zone on the ceramic side obey parabolic growth laws of time, with activation energies in the range Q=310-460kJmol-1. The amount of dissolved Si, the length of the diffusion zone and thus the reactivity of the ceramic increase as the alloy carbon content decreases. Due to Si accumulation, the α-Fe solid solution is stabilised at the reaction temperature and a steep decrease in the Si concentration is observed beyond the diffusion zone. The reinforcement of the Si3N4 composites with A12O3 platelets enhances the chemical resistance of the ceramic due to the inertness of this oxide and to the partial crystallisation of the intergranular phase. Other dispersoids such as HfN, BN and TiN do not improve the chemical resistance of the matrix by iron attack.

    Los experimentos de difusión metal/cerámica permiten estudiar mecanismos de unión y analizar el efecto de la composición del metal en el desgaste químico de herramientas de corte cerámicas. En este trabajo se investigó la cinética de reacción en pares de difusión aleaciones de Fe/Si3N4 a temperaturas entre 1050ºC-1250ºC, tiempos entre 0.5h a 80h, en atmósfera inerte. Las secciones transversales de los pares de difusión se analizaron mediante microscopía óptica, SEM y microsonda electrónica. El Si3N4 se descompone en Si y N que se disuelven y difunden en el metal. Tanto la zona de difusión en el metal como la zona de reacción en la cer

  6. Characterization of sapphire: For its material properties at high temperatures

    Science.gov (United States)

    Bal, Harman Singh

    There are numerous needs for sensing, one of which is in pressure sensing for high temperature application such as combustion related process and embedded in aircraft wings for reusable space vehicles. Currently, silicon based MEMS technology is used for pressure sensing. However, due to material properties the sensors have a limited range of approximately 600 °C which is capable of being pushed towards 1000 °C with active cooling. This can introduce reliability issues when you add more parts and high flow rates to remove large amounts of heat. To overcome this challenge, sapphire is investigated for optical based pressure transducers at temperatures approaching 1400 °C. Due to its hardness and chemical inertness, traditional cutting and etching methods used in MEMS technology are not applicable. A method that is being investigated as a possible alternative is laser machining using a picosecond laser. In this research, we study the material property changes that occur from laser machining and quantify the changes with the experimental results obtained by testing sapphire at high-temperature with a standard 4-point bending set-up.

  7. High-throughput exposure modeling to support prioritization of chemicals in personal care products

    DEFF Research Database (Denmark)

    Csiszar, Susan A.; Ernstoff, Alexi; Fantke, Peter

    2016-01-01

    -on and wash-off products which had median PiFs of 0.5 and 0.02 across the 518 chemicals, respectively. The PiF is a function of product characteristics and physico-chemical properties and is maximized when skin permeability is high and volatility is low such that there is no competition between skin and air...

  8. A coupled model between mechanical deformation and chemical diffusion: An explanation for the preservation of chemical zonation in plagioclase at high temperatures

    Science.gov (United States)

    Zhong, Xin; Vrijmoed, Johannes; Moulas, Evangelos; Tajcmanová, Lucie

    2016-04-01

    Compositional zoning in metamorphic minerals have been generally recognized as an important geological feature to decipher the metamorphic history of rocks. The observed chemical zoning of, e.g. garnet, is commonly interpreted as disequilibrium between the fractionated inner core and the surrounding matrix. However, chemically zoned minerals were also observed in high grade rocks (T>800 degree C) where the duration of metamorphic processes was independently dated to take several Ma. This implies that temperature may not be the only factor that controls diffusion timescales, and grain scale pressure variation was proposed to be a complementary factor that may significantly contribute to the formation and preservation of chemical zoning in high temperature metamorphic minerals [Tajcmanová 2013, 2015]. Here, a coupled model is developed to simulate viscous deformation and chemical diffusion. The numerical approach considers the conservation of mass, momentum, and a constitutive relation developed from equilibrium thermodynamics. A compressible viscoelastic rheology is applied, which associates the volumetric change triggered by deformation and diffusion to a change of pressure. The numerical model is applied to the chemically zoned plagioclase rim described by [Tajcmanová 2014]. The diffusion process operating during the plagioclase rim formation can lead to a development of a pressure gradient. Such a pressure gradient, if maintained during ongoing viscous relaxation, can lead to the preservation of the observed chemical zonation in minerals. An important dimensionless number, the Deborah number, is defined as the ratio between the Maxwell viscoelastic relaxation time and the characteristic diffusion time. It characterizes the relative influence between the maintenance of grain scale pressure variation and chemical diffusion. Two extreme regimes are shown: the mechanically-controlled regime (high Deborah number) and diffusion-controlled regime (low Deborah number

  9. The evolution of the temperature field during cavity collapse in liquid nitromethane. Part I: inert case

    Science.gov (United States)

    Michael, L.; Nikiforakis, N.

    2018-02-01

    This work is concerned with the effect of cavity collapse in non-ideal explosives as a means of controlling their sensitivity. The main objective is to understand the origin of localised temperature peaks (hot spots) which play a leading order role at the early stages of ignition. To this end, we perform two- and three-dimensional numerical simulations of shock-induced single gas-cavity collapse in liquid nitromethane. Ignition is the result of a complex interplay between fluid dynamics and exothermic chemical reaction. In order to understand the relative contribution between these two processes, we consider in this first part of the work the evolution of the physical system in the absence of chemical reactions. We employ a multi-phase mathematical formulation which can account for the large density difference across the gas-liquid material interface without generating spurious temperature peaks. The mathematical and physical models are validated against experimental, analytic, and numerical data. Previous inert studies have identified the impact of the upwind (relative to the direction of the incident shock wave) side of the cavity wall to the downwind one as the main reason for the generation of a hot spot outside of the cavity, something which is also observed in this work. However, it is also apparent that the topology of the temperature field is more complex than previously thought and additional hot spot locations exist, which arise from the generation of Mach stems rather than jet impact. To explain the generation mechanisms and topology of the hot spots, we carefully follow the complex wave patterns generated in the collapse process and identify specifically the temperature elevation or reduction generated by each wave. This enables tracking each hot spot back to its origins. It is shown that the highest hot spot temperatures can be more than twice the post-incident shock temperature of the neat material and can thus lead to ignition. By comparing two

  10. Substrate selection for fundamental studies of electrocatalysts and photoelectrodes: inert potential windows in acidic, neutral, and basic electrolyte.

    Directory of Open Access Journals (Sweden)

    Jesse D Benck

    Full Text Available The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide. We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

  11. Effect of sonication on particle dispersion, administered dose and metal release of non-functionalized, non-inert metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Sulena; Hedberg, Jonas, E-mail: jhed@kth.se; Blomberg, Eva [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry (Sweden); Wold, Susanna [KTH Royal Institute of Technology, Division of Applied Physical Chemistry, Department of Chemistry (Sweden); Odnevall Wallinder, Inger [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry (Sweden)

    2016-09-15

    In this study, we elucidate the effect of different sonication techniques to efficiently prepare particle dispersions from selected non-functionalized NPs (Cu, Al, Mn, ZnO), and corresponding consequences on the particle dose, surface charge and release of metals. Probe sonication was shown to be the preferred method for dispersing non-inert, non-functionalized metal NPs (Cu, Mn, Al). However, rapid sedimentation during sonication resulted in differences between the real and the administered doses in the order of 30–80 % when sonicating in 1 and 2.56 g/L NP stock solutions. After sonication, extensive agglomeration of the metal NPs resulted in rapid sedimentation of all particles. DLVO calculations supported these findings, showing the strong van der Waals forces of the metal NPs to result in significant NP agglomeration. Metal release from the metal NPs was slightly increased by increased sonication. The addition of a stabilizing agent (bovine serum albumin) had an accelerating effect on the release of metals in sonicated solutions. For Cu and Mn NPs, the extent of particle dissolution increased from <1.6 to ~5 % after sonication for 15 min. A prolonged sonication time (3–15 min) had negligible effects on the zeta potential of the studied NPs. In all, it is shown that it is of utmost importance to carefully investigate how sonication influences the physico-chemical properties of dispersed metal NPs. This should be considered in nanotoxicology investigations of metal NPs.Graphical Abstract.

  12. Apparatus and method for enhanced chemical processing in high pressure and atmospheric plasmas produced by high frequency electromagnetic waves

    Science.gov (United States)

    Efthimion, Philip C.; Helfritch, Dennis J.

    1989-11-28

    An apparatus and method for creating high temperature plasmas for enhanced chemical processing of gaseous fluids, toxic chemicals, and the like, at a wide range of pressures, especially at atmospheric and high pressures includes an electro-magnetic resonator cavity, preferably a reentrant cavity, and a wave guiding structure which connects an electro-magnetic source to the cavity. The cavity includes an intake port and an exhaust port, each having apertures in the conductive walls of the cavity sufficient for the intake of the gaseous fluids and for the discharge of the processed gaseous fluids. The apertures are sufficiently small to prevent the leakage of the electro-magnetic radiation from the cavity. Gaseous fluid flowing from the direction of the electro-magnetic source through the guiding wave structure and into the cavity acts on the plasma to push it away from the guiding wave structure and the electro-magnetic source. The gaseous fluid flow confines the high temperature plasma inside the cavity and allows complete chemical processing of the gaseous fluids at a wide range of pressures.

  13. Physico-chemical mechanism for the vapors sensitivity of photoluminescent InP quantum dots

    Science.gov (United States)

    Prosposito, P.; De Angelis, R.; De Matteis, F.; Hatami, F.; Masselink, W. T.; Zhang, H.; Casalboni, M.

    2016-03-01

    InP/InGaP surface quantum dots are interesting materials for optical chemical sensors since they present an intense emission at room temperature, whose intensity changes rapidly and reversibly depending on the composition of the environmental atmosphere. We present here their emission properties by time resolved photoluminescence spectroscopy investigation and we discuss the physico-chemical mechanism behind their sensitivity to the surrounding atmosphere. Photoluminescence transients in inert atmosphere (N2) and in solvent vapours of methanol, clorophorm, acetone and water were measured. The presence of vapors of clorophorm, acetone and water showed a very weak effect on the transient times, while an increase of up to 15% of the decay time was observed for methanol vapour exposure. On the basis of the vapor molecule nature (polarity, proticity, steric hindrance, etc.) and of the interaction of the vapor molecules with the quantum dots surface a sensing mechanism involving quantum dots non-radiative surface states is proposed.

  14. Physico-chemical mechanism for the vapors sensitivity of photoluminescent InP quantum dots

    International Nuclear Information System (INIS)

    Prosposito, P.; De Angelis, R.; De Matteis, F.; Casalboni, M.; Hatami, F.; Masselink, W.T.; Zhang, H.

    2016-01-01

    InP/InGaP surface quantum dots are interesting materials for optical chemical sensors since they present an intense emission at room temperature, whose intensity changes rapidly and reversibly depending on the composition of the environmental atmosphere. We present here their emission properties by time resolved photoluminescence spectroscopy investigation and we discuss the physico-chemical mechanism behind their sensitivity to the surrounding atmosphere. Photoluminescence transients in inert atmosphere (N 2 ) and in solvent vapours of methanol, chloroform, acetone and water were measured. The presence of vapors of chloroform, acetone and water showed a very weak effect on the transient times, while an increase of up to 15% of the decay time was observed for methanol vapour exposure. On the basis of the vapor molecule nature (polarity, proticity, steric hindrance, etc.) and of the interaction of the vapor molecules with the quantum dots surface a sensing mechanism involving quantum dots non-radiative surface states is proposed. (paper)

  15. Chemical compatibility study of lithium titanate with Indian reduced activation ferritic martensitic steel

    International Nuclear Information System (INIS)

    Sonak, Sagar; Jain, Uttam; Haldar, Rumu; Kumar, Sanjay

    2015-01-01

    Highlights: • Chemical compatibility between Li_2TiO_3 and Indian RAFM steel has been studied at ITER operating temperature. • The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. • The layer grew in a parabolic manner as a function of heating time. • Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer. - Abstract: Chemical compatibility between lithium titanate and Indian reduced activation ferritic-martensitic steel (In-RAFMS) was studied for the first time under ITER operating temperature. Lithium titanate required for the study was synthesized in-house. Coupons of In-RAFMS were packed inside lithium titanate powder and heated at 550 °C up to 900 h under inert argon atmosphere. The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. The layer grew in a parabolic manner as a function of heating time. Microstructural and phase evolution of this oxide layer was studied using XRD, SEM and EPMA. Iron and chromium enriched zones were found within the oxide layer. Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer.

  16. Experimental results of direct containment heating by high-pressure melt ejection into the Surtsey vessel: The DCH-3 and DCH-4 tests

    International Nuclear Information System (INIS)

    Allen, M.D.; Pilch, M.; Brockmann, J.E.; Tarbell, W.W.; Nichols, R.T.; Sweet, D.W.

    1991-08-01

    Two experiments, DCH-3 and DCH-4, were performed at the Surtsey test facility to investigate phenomena associated with a high-pressure melt ejection (HPME) reactor accident sequence resulting in direct containment heating (DCH). These experiments were performed using the same experimental apparatus with identical initial conditions, except that the Surtsey test vessel contained air in DCH-3 and argon in DCH-4. Inerting the vessel with argon eliminated chemical reactions between metallic debris and oxygen. Thus, a comparison of the pressure response in DCH-3 and DCH-4 gave an indication of the DCH contribution due to metal/oxygen reactions. 44 refs., 110 figs., 43 tabs

  17. Experimental results of direct containment heating by high-pressure melt ejection into the Surtsey vessel: The DCH-3 and DCH-4 tests

    Energy Technology Data Exchange (ETDEWEB)

    Allen, M.D.; Pilch, M.; Brockmann, J.E.; Tarbell, W.W. (Sandia National Labs., Albuquerque, NM (United States)); Nichols, R.T. (Ktech Corp., Albuquerque, NM (United States)); Sweet, D.W. (AEA Technology, Winfrith (United Kingdom))

    1991-08-01

    Two experiments, DCH-3 and DCH-4, were performed at the Surtsey test facility to investigate phenomena associated with a high-pressure melt ejection (HPME) reactor accident sequence resulting in direct containment heating (DCH). These experiments were performed using the same experimental apparatus with identical initial conditions, except that the Surtsey test vessel contained air in DCH-3 and argon in DCH-4. Inerting the vessel with argon eliminated chemical reactions between metallic debris and oxygen. Thus, a comparison of the pressure response in DCH-3 and DCH-4 gave an indication of the DCH contribution due to metal/oxygen reactions. 44 refs., 110 figs., 43 tabs.

  18. ChemicalVia: a CERN-patented technology for use in high-density circuits

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    High-density multilayer printed circuits such as those pictured here are found in miniaturized modern equipment from video cameras to mobile phones. Adjacent layers in these circuits are electrically connected by microvias, consisting of a small-diameter hole (usually 50 µm) with a thin metal-deposited surface covering their cylindrical walls to ensure local conductivity between the two layers. ChemicalVia is a new method, patented by CERN, to make microvias on high-density multilayer printed circuits using chemicals rather than complex laser, plasma or photoimaging technology. The process is compatible with all standard printed-circuit assembly lines, and has the advantages of low initial investment and reduced manufacturing costs. http://www.cern.ch/ttdatabase

  19. Hydrogeological investigations in the Harwell region: the use of environmental isotopes, inert gas contents, and the uranium decay series

    International Nuclear Information System (INIS)

    Alexander, J.; Andrews, J.N.

    1984-12-01

    A comprehensive range of environmental isotopes, radioelement and dissolved gas contents have been measured in groundwaters from the high permeability formations of the Harwell area. These analyses were undertaken as part of a hydrochemical validation of groundwater circulation patterns derived from potentiometric data. These investigations have focused upon the Corallian and Great Oolite formations since these sandwich the Oxford Clay. Geochemical, isotopic, radioelement and inert gas studies have demonstrated consistent trends which substantiate fluid migration patterns derived from hydraulic considerations. Groundwaters at downdip localities in both the Corallian and Great Oolite formations are the oldest waters sampled from the region. Variations in trends in parameters can be attributed to cross-formational flow and subsequent mixing of groundwaters. Individually these techniques can only provide limited information, but the combination of methods used have provided corroborative evidence concerning the direction of fluid circulation in the Harwell region. (author)

  20. Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries

    Science.gov (United States)

    Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

    2016-11-01

    It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle-1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance.

  1. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1999-01-01

    High Resolution NMR provides a broad treatment of the principles and theory of nuclear magnetic resonance (NMR) as it is used in the chemical sciences. It is written at an "intermediate" level, with mathematics used to augment, rather than replace, clear verbal descriptions of the phenomena. The book is intended to allow a graduate student, advanced undergraduate, or researcher to understand NMR at a fundamental level, and to see illustrations of the applications of NMR to the determination of the structure of small organic molecules and macromolecules, including proteins. Emphasis is on the study of NMR in liquids, but the treatment also includes high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. Careful attention is given to developing and interrelating four approaches - steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The presentation is based on the assumption that the reader has an acquaintan...

  2. The anisotropic potential of molecular hydrogen determined from the scattering of oriented H2 on inert gases

    International Nuclear Information System (INIS)

    Zandee, A.P.L.M.

    1977-01-01

    This thesis deals with an experiment aimed at determining the angle dependence of an intermolecular potential between H 2 molecule and a rare gas atom. The small relative difference in total collision cross section for beams of differently oriented H 2 molecules colliding with inert gas atoms in a scattering box is measured (anisotropy A). Through variation of the orientation and by studying its influence on the total collision cross sections, the angle dependence of the intermolecular potential can be arrived at

  3. Direct observation and analysis of yolk-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

    Energy Technology Data Exchange (ETDEWEB)

    Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki [JEOL Ltd., SM Business Unit, Tokyo (Japan); Young Jeong, Hu [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Galeano, Carolina; Schüth, Ferdi [Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Mülheim (Germany); Terasaki, Osamu, E-mail: terasaki@mmk.su.se, E-mail: terasaki@kaist.ac.kr [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Department of Materials and Environmental Chemistry, Berzelii Centre EXSELENT on Porous Materials, Stockholm University, SE-10691 Stockholm (Sweden)

    2014-11-01

    Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO{sub 2}, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

  4. Conformally invariant Inert Higgs doublet model: an unified model for Inflation and Dark matter

    International Nuclear Information System (INIS)

    Das, Moumita; Mohanty, Subhendra

    2012-01-01

    Motivation of our present study is the searching for an unified model which can describe both the inflation as well as dark matter. From particle physics point of view, Higgs can be the most interesting candidate for the scalar field inflation. Conformal coupling of the inflaton with the gravity can generate the density perturbation and we use this idea in a realistic inert Higgs doublet model. We study the loop corrections of this conformally coupled system and in present era there is electroweak symmetry breaking to provide the mass of the particles. Study of the mass spectrum in present era reveals the scalar dark matter with mass 33.7 GeV and lightest Higgs at 125.6 GeV.

  5. 75 FR 8575 - Testing of Certain High Production Volume Chemicals; Third Group of Chemicals

    Science.gov (United States)

    2010-02-25

    ...: Beilstein Database, CRC Handbook of Chemistry and Physics, Hawley's Condensed Chemical Dictionary, Illustrated Handbooks of Physical- Chemical Properties and Environmental Fate for Organic Chemicals, Merck... Coefficient: Method A (40 CFR 799.6755--shake flask). Method B (ASTM E 1147-92(2005)--liquid chromatography...

  6. Remote-controlling chemical reactions by light: towards chemistry with high spatio-temporal resolution.

    Science.gov (United States)

    Göstl, Robert; Senf, Antti; Hecht, Stefan

    2014-03-21

    The foundation of the chemical enterprise has always been the creation of new molecular entities, such as pharmaceuticals or polymeric materials. Over the past decades, this continuing effort of designing compounds with improved properties has been complemented by a strong effort to render their preparation (more) sustainable by implementing atom as well as energy economic strategies. Therefore, synthetic chemistry is typically concerned with making specific bonds and connections in a highly selective and efficient manner. However, to increase the degree of sophistication and expand the scope of our work, we argue that the modern aspiring chemist should in addition be concerned with attaining (better) control over when and where chemical bonds are being made or broken. For this purpose, photoswitchable molecular systems, which allow for external modulation of chemical reactions by light, are being developed and in this review we are covering the current state of the art of this exciting new field. These "remote-controlled synthetic tools" provide a remarkable opportunity to perform chemical transformations with high spatial and temporal resolution and should therefore allow regulating biological processes as well as material and device performance.

  7. A modified parallel artificial membrane permeability assay for evaluating the bioconcentration of highly hydrophobic chemicals in fish.

    Science.gov (United States)

    Kwon, Jung-Hwan; Escher, Beate I

    2008-03-01

    Low cost in vitro tools are needed at the screening stage of assessment of bioaccumulation potential of new and existing chemicals because the number of chemical substances that needs to be tested highly exceeds the capacity of in vivo bioconcentration tests. Thus, the parallel artificial membrane permeability assay (PAMPA) system was modified to predict passive uptake/ elimination rate in fish. To overcome the difficulties associated with low aqueous solubility and high membrane affinity of highly hydrophobic chemicals, we measured the rate of permeation from the donor poly(dimethylsiloxane)(PDMS) disk to the acceptor PDMS disk through aqueous and PDMS membrane boundary layers and term the modified PAMPA system "PDMS-PAMPA". Twenty chemicals were selected for validation of PDMS-PAMPA. The measured permeability is proportional to the passive elimination rate constant in fish and was used to predict the "minimum" in vivo elimination rate constant. The in vivo data were very close to predicted values except for a few polar chemicals and metabolically active chemicals, such as pyrene and benzo[a]pyrene. Thus, PDMS-PAMPA can be an appropriate in vitro system for nonmetabolizable chemicals. Combination with metabolic clearance rates using a battery of metabolic degradation assays would enhance the applicability for metabolizable chemicals.

  8. Device and method for enhanced collection and assay of chemicals with high surface area ceramic

    Science.gov (United States)

    Addleman, Raymond S.; Li, Xiaohong Shari; Chouyyok, Wilaiwan; Cinson, Anthony D.; Bays, John T.; Wallace, Krys

    2016-02-16

    A method and device for enhanced capture of target analytes is disclosed. This invention relates to collection of chemicals for separations and analysis. More specifically, this invention relates to a solid phase microextraction (SPME) device having better capability for chemical collection and analysis. This includes better physical stability, capacity for chemical collection, flexible surface chemistry and high affinity for target analyte.

  9. Crystallization and growth of Ni-Si alloy thin films on inert and on silicon substrates

    Science.gov (United States)

    Grimberg, I.; Weiss, B. Z.

    1995-04-01

    The crystallization kinetics and thermal stability of NiSi2±0.2 alloy thin films coevaporated on two different substrates were studied. The substrates were: silicon single crystal [Si(100)] and thermally oxidized silicon single crystal. In situ resistance measurements, transmission electron microscopy, x-ray diffraction, Auger electron spectroscopy, and Rutherford backscattering spectroscopy were used. The postdeposition microstructure consisted of a mixture of amorphous and crystalline phases. The amorphous phase, independent of the composition, crystallizes homogeneously to NiSi2 at temperatures lower than 200 °C. The activation energy, determined in the range of 1.4-2.54 eV, depends on the type of the substrate and on the composition of the alloyed films. The activation energy for the alloys deposited on the inert substrate was found to be lower than for the alloys deposited on silicon single crystal. The lowest activation energy was obtained for nonstoichiometric NiSi2.2, the highest for NiSi2—on both substrates. The crystallization mode depends on the structure of the as-deposited films, especially the density of the existing crystalline nuclei. Substantial differences were observed in the thermal stability of the NiSi2 compound on both substrates. With the alloy films deposited on the Si substrate, only the NiSi2 phase was identified after annealing to temperatures up to 800 °C. In the films deposited on the inert substrate, NiSi and NiSi2 phases were identified when the Ni content in the alloy exceeded 33 at. %. The effects of composition and the type of substrate on the crystallization kinetics and thermal stability are discussed.

  10. Chemical Stability Analysis of Hair Cleansing Conditioners under High-Heat Conditions Experienced during Hair Styling Processes

    Directory of Open Access Journals (Sweden)

    Derek A. Drechsel

    2018-03-01

    Full Text Available Chemical stability is a key component of ensuring that a cosmetic product is safe for consumer use. The objective of this study was to evaluate the chemical stability of commercially available hair cleansing conditioners subjected to high heat stresses from the styling processes of blow drying or straightening. Two hair cleansing conditioners were subjected to temperatures of 60 °C and 185 °C to simulate the use of a blow dryer or flatiron hair straightener, respectively and analyzed via Gas Chromatography-Mass Spectrometry (GC-MS, High-Performance Liquid Chromatography-UV (HPLC and Fourier-Transform Infrared Spectroscopy (FT-IR to capture a chemical profile of the samples. The resulting spectra from matched heated and unheated samples were compared to identify any changes in chemical composition. Overall, no differences in the spectra were observed between the heated and unheated samples at both temperatures evaluated. Specifically, no new peaks were observed during analysis, indicating that no degradation products were formed. In addition, all chemicals identified during GC-MS analysis were known listed ingredients of the products. In summary, no measurable changes in chemical composition were observed in the hair cleansing conditioner samples under high-heat stress conditions. The presented analytical methods can serve as an initial screening tool to evaluate the chemical stability of a cosmetic product under conditions of anticipated use.

  11. Facile and high spatial resolution ratio-metric luminescence thermal mapping in microfluidics by near infrared excited upconversion nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu; Li, Shunbo; Wen, Weijia, E-mail: phwen@ust.hk [Department of Physics, KAUST-HKUST Joint Micro/Nanofluidic Laboratory, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Cao, Wenbin [Nano Science and Technology Program, Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2016-02-01

    A local area temperature monitor is important for precise control of chemical and biological processes in microfluidics. In this work, we developed a facile method to realize micron spatial resolution of temperature mapping in a microfluidic channel quickly and cost effectively. Based on the temperature dependent fluorescence emission of NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} upconversion nanoparticles (UCNPs) under near-infrared irradiation, ratio-metric imaging of UCNPs doped polydimethylsiloxane can map detailed temperature distribution in the channel. Unlike some reported strategies that utilize temperature sensitive organic dye (such as Rhodamine) to achieve thermal sensing, our method is highly chemically inert and physically stable without any performance degradation in long term operation. Moreover, this method can be easily scaled up or down, since the spatial and temperature resolution is determined by an optical imaging system. Our method supplied a simple and efficient solution for temperature mapping on a heterogeneous surface where usage of an infrared thermal camera was limited.

  12. Facile and high spatial resolution ratio-metric luminescence thermal mapping in microfluidics by near infrared excited upconversion nanoparticles

    International Nuclear Information System (INIS)

    Wang, Yu; Li, Shunbo; Wen, Weijia; Cao, Wenbin

    2016-01-01

    A local area temperature monitor is important for precise control of chemical and biological processes in microfluidics. In this work, we developed a facile method to realize micron spatial resolution of temperature mapping in a microfluidic channel quickly and cost effectively. Based on the temperature dependent fluorescence emission of NaYF 4 :Yb 3+ , Er 3+ upconversion nanoparticles (UCNPs) under near-infrared irradiation, ratio-metric imaging of UCNPs doped polydimethylsiloxane can map detailed temperature distribution in the channel. Unlike some reported strategies that utilize temperature sensitive organic dye (such as Rhodamine) to achieve thermal sensing, our method is highly chemically inert and physically stable without any performance degradation in long term operation. Moreover, this method can be easily scaled up or down, since the spatial and temperature resolution is determined by an optical imaging system. Our method supplied a simple and efficient solution for temperature mapping on a heterogeneous surface where usage of an infrared thermal camera was limited

  13. Implementation of high-dose chemical dosimetry for industrial facilities

    International Nuclear Information System (INIS)

    Conceicao, Cirilo Cezar Sant'Anna da

    2006-01-01

    The purpose of this work is the implementation of methodology for high dose measurements using chemical dosimeters in liquid phase, traceable to the international metrology system, and make available in the country, the standard of high-dose to industrial irradiation facilities and research irradiators, trough the quality program with comparative measurements and direct use of the standard dosimeters in routine. The use of these low cost dosimetry systems in industrial irradiation facilities, assists to the certification requirements and it can reduce the costs with dosimetry for approximately 20% of the total dosimetry costs, using these systems in routine measurements and validation process, largely substituting the imported PMMA dosimeters, among others. (author)

  14. Labile/inert metal species in aquatic humic substances: an ion-exchange study

    International Nuclear Information System (INIS)

    Burba, P.

    1994-01-01

    An ion-exchange procedure has been developed for the analytical fractionation of metals (e.g. Al, Co, Cu, Fe, Mn, Ni, Pb, Zn) forming labile/inert complexes with aquatic humic substances (HS) isolated (XAD 2, XAD 8, ultrafiltration) from bog, forest, ground and lake water. Using 1-(2-hydroxyphenylazo)-2-naphthol groups immobilized on cellulose (Cellulose HYPHAN TM ) as chelating collector (batch and column procedure, resp.) for reactive metal fractions in dissolved HS, the kinetics and the degree of separation (referred to the total metal content) serve for the operational characterization of the metal lability. According to the separation kinetics (96 h), mostly the reactivity order Mn > Zn > Co > Pb > Ni > Cu >> Al > Fe is observed for the above metals in HS, resulting in recoveries of > 98% for Mn and Zn, but strongly varying for the other metals (e.g., 44-95% Cu, 18-84% Fe). (orig.)

  15. Porous SiO_2 nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

    International Nuclear Information System (INIS)

    Das, Indranee; De, Goutam; Hupa, Leena; Vallittu, Pekka K.

    2016-01-01

    A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO_2 nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

  16. High-performance macroporous bulk silicon anodes synthesized by template-free chemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Byoung Man; Lee, Jung-In; Kim, Hyunjung; Cho, Jaephil; Park, Soojin [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of)

    2012-07-15

    Three-dimensional porous silicon particles can be produced via the combination of a galvanic displacement reaction and a metal-assisted chemical etching process. This simple synthetic route can be applied to make high-performance anode materials, including high specific capacity, stable cycling retention, and high rate capability, in lithium-ion batteries. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Behavioural response of Phytoseiulus persimilisin inert materials for technical application.

    Science.gov (United States)

    Wendorf, Dennis; Sermann, Helga; Katz, Peter; Lerche, Sandra; Büttner, Carmen

    2009-01-01

    A large scale application of the predatory mite Phytoseiulus persimilis Athias-Henriot for use in the biological control of spider mites in the field requires testing the behaviour of Phytoseiulus persimilis in inert materials, like millet pelts and Vermiculite (1-3 mm). In laboratory studies, the distribution of the individuals in such materials, the time of remaining in the material were proved. To examine the abiotic influences on the time of remaining in the material, the dampness of the materials was varied (0%, 5% and 10%). Moreover, the influence of attitude of materials was tested. The time of emigration from the material was noted for each individual. Emigration from all dry materials was completed 15 minutes at the latest after set up of the mites. The increase of dampness had an obvious effect on the time of remaining in the material. In this respect the material millet pelts showed the most favourable effect with 10% dampness. Increasing attitude of material the mobility of predatory mites will be influenced negatively above 75 cm. Up to 50 cm, mites have not a problem to move in the material and the time of remaining can be prolonged considerably.

  18. High-Throughput Screening of Chemical Effects on Steroidogenesis Using H295R Human Adrenocortical Carcinoma Cells.

    Science.gov (United States)

    Karmaus, Agnes L; Toole, Colleen M; Filer, Dayne L; Lewis, Kenneth C; Martin, Matthew T

    2016-04-01

    Disruption of steroidogenesis by environmental chemicals can result in altered hormone levels causing adverse reproductive and developmental effects. A high-throughput assay using H295R human adrenocortical carcinoma cells was used to evaluate the effect of 2060 chemical samples on steroidogenesis via high-performance liquid chromatography followed by tandem mass spectrometry quantification of 10 steroid hormones, including progestagens, glucocorticoids, androgens, and estrogens. The study employed a 3 stage screening strategy. The first stage established the maximum tolerated concentration (MTC; ≥ 70% viability) per sample. The second stage quantified changes in hormone levels at the MTC whereas the third stage performed concentration-response (CR) on a subset of samples. At all stages, cells were prestimulated with 10 µM forskolin for 48 h to induce steroidogenesis followed by chemical treatment for 48 h. Of the 2060 chemical samples evaluated, 524 samples were selected for 6-point CR screening, based in part on significantly altering at least 4 hormones at the MTC. CR screening identified 232 chemical samples with concentration-dependent effects on 17β-estradiol and/or testosterone, with 411 chemical samples showing an effect on at least one hormone across the steroidogenesis pathway. Clustering of the concentration-dependent chemical-mediated steroid hormone effects grouped chemical samples into 5 distinct profiles generally representing putative mechanisms of action, including CYP17A1 and HSD3B inhibition. A distinct pattern was observed between imidazole and triazole fungicides suggesting potentially distinct mechanisms of action. From a chemical testing and prioritization perspective, this assay platform provides a robust model for high-throughput screening of chemicals for effects on steroidogenesis. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology.

  19. The ground water chemical characteristics of Beishan area-the China's potential high level radioactive waste repository

    International Nuclear Information System (INIS)

    Yang Tianxiao; Guo Yonghai

    2004-01-01

    The ground water chemical characteristics have impact on nuclide migration in high level waste repository, so the study on the ground water chemical characteristics is an important aspect in site screening and characterization. The geochemical modeling of the reaction trend between ground water and solid phase, the water-rock interaction modeling of the formation and evolution of ground water chemistry, the modeling of the reaction between ground water and nuclear waste are all carried out in this paper to study the ground water chemical characteristics in Beishan area. The study illustrates that the ground water chemical characteristics in Beishan area is favorable to the disposal of high level nuclear waste and to prevent the nuclides migration. (author)

  20. Covalent functionalization of silicon nitride surfaces for anti-biofouling and bioselective capture

    NARCIS (Netherlands)

    Nguyen, A.T.

    2011-01-01

    Microsieves – microengineered membranes – have been introduced in microfiltration technology as a new generation of inorganic membranes. The thin membranes are made of silicon nitride (SixN4), which gives the membranes outstanding features, such as chemical inertness and high mechanical

  1. Heavy ion induced damage in MgAl sub 2 O sub 4 , an inert matrix candidate for the transmutation of minor actinides

    CERN Document Server

    Wiss, T

    1999-01-01

    Magnesium aluminum spinel (MgAl sub 2 O sub 4) is a material selected as a possible matrix for transmutation of minor actinides by neutron capture or fission in nuclear reactors. To study the radiation stability of this inert matrix, especially against fission product impact, irradiations with heavy energetic ions or clusters have been performed. The high electronic energy losses of the heavy ions in this material led to the formation of visible tracks as evidenced by transmission electron microscopy for 30 MeV C sub 6 sub 0 -Buckminster fullerenes and for ions of energy close to or higher than fission energy ( sup 2 sup 0 sup 9 Bi with 120 MeV and 2.38 GeV energy). The irradiations at high energies showed a pronounced degradation of the spinel. Additionally, MgAl sub 2 O sub 4 exhibited a large swelling for irradiation at high fluences with fission products of fission energy (here I-ions of 72 MeV) and at temperatures <= 500 deg. C. These observations are discussed from the technological point of view in ...

  2. Interstellar matrices: the chemical composition and evolution of interstellar ices as observed by ISO.

    Science.gov (United States)

    d'Hendecourt, L; Dartois, E

    2001-03-15

    Matrix isolation techniques have been developed in the early sixties as a tool for studying the spectroscopic properties of out of equilibrium species (atoms, radicals, ions, reactive molecules), embedded in rare gas inert matrices at low temperatures. Cold interstellar grains surfaces are able to condense out gas phase molecules, routinely observed by radioastronomy. These grain 'mantles' can be considered as 'interstellar matrices'. However, these matrices are not clean and unreactive. They are made principally of dirty ices whose composition must be determined carefully to assess the importance of the solid state chemistry that takes place in the Interstellar Medium. Infrared spectroscopy, both in astronomy and in the laboratory, is the unique tool to determine the chemical composition of these ices. Astronomical spectra can directly be compared with laboratory ones obtained using classical matrix isolation techniques. Furthermore, dedicated experiments may be undertaken to further improve the understanding of the basic physico-chemical processes that take place in cosmic ices.

  3. Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

    Science.gov (United States)

    Kumpiene, Jurate; Robinson, Ryan; Brännvall, Evelina; Nordmark, Désirée; Bjurström, Henrik; Andreas, Lale; Lagerkvist, Anders; Ecke, Holger

    2011-01-01

    Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Development of an Instrument to Evaluate High School Students' Chemical Symbol Representation Abilities

    Science.gov (United States)

    Wang, Zuhao; Chi, Shaohui; Luo, Ma; Yang, Yuqin; Huang, Min

    2017-01-01

    Chemical symbol representation is a medium for transformations between the actual phenomena of the macroscopic world and those of the sub-microscopic world. The aim of this study is to develop an instrument to evaluate high school students' chemical symbol representation abilities (CSRA). Based on the current literature, we defined CSRA and…

  5. Job Relocation is High in Chemical Industry.

    Science.gov (United States)

    Chemical and Engineering News, 1979

    1979-01-01

    The chances of an employee being relocated are higher in the chemical and plastics industries than in U.S. business as a whole. But the benefits provided by chemical and plastics companies to employees shifted to other locations are generally better than average. (Author/BB)

  6. Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors.

    Science.gov (United States)

    McAlpine, Michael C; Ahmad, Habib; Wang, Dunwei; Heath, James R

    2007-05-01

    The development of a robust method for integrating high-performance semiconductors on flexible plastics could enable exciting avenues in fundamental research and novel applications. One area of vital relevance is chemical and biological sensing, which if implemented on biocompatible substrates, could yield breakthroughs in implantable or wearable monitoring systems. Semiconducting nanowires (and nanotubes) are particularly sensitive chemical sensors because of their high surface-to-volume ratios. Here, we present a scalable and parallel process for transferring hundreds of pre-aligned silicon nanowires onto plastic to yield highly ordered films for low-power sensor chips. The nanowires are excellent field-effect transistors, and, as sensors, exhibit parts-per-billion sensitivity to NO2, a hazardous pollutant. We also use SiO2 surface chemistries to construct a 'nano-electronic nose' library, which can distinguish acetone and hexane vapours via distributed responses. The excellent sensing performance coupled with bendable plastic could open up opportunities in portable, wearable or even implantable sensors.

  7. Highly ordered nanowire arrays on plastic substrates for ultrasensitive flexible chemical sensors

    Science.gov (United States)

    McAlpine, Michael C.; Ahmad, Habib; Wang, Dunwei; Heath, James R.

    2007-05-01

    The development of a robust method for integrating high-performance semiconductors on flexible plastics could enable exciting avenues in fundamental research and novel applications. One area of vital relevance is chemical and biological sensing, which if implemented on biocompatible substrates, could yield breakthroughs in implantable or wearable monitoring systems. Semiconducting nanowires (and nanotubes) are particularly sensitive chemical sensors because of their high surface-to-volume ratios. Here, we present a scalable and parallel process for transferring hundreds of pre-aligned silicon nanowires onto plastic to yield highly ordered films for low-power sensor chips. The nanowires are excellent field-effect transistors, and, as sensors, exhibit parts-per-billion sensitivity to NO2, a hazardous pollutant. We also use SiO2 surface chemistries to construct a `nano-electronic nose' library, which can distinguish acetone and hexane vapours via distributed responses. The excellent sensing performance coupled with bendable plastic could open up opportunities in portable, wearable or even implantable sensors.

  8. Analysis of cracks in stainless steel TIG [tungsten inert gas] welds

    International Nuclear Information System (INIS)

    Nakagaki, M.; Marschall, C.; Brust, F.

    1986-12-01

    This report contains the results of a combined experimental and analytical study of ductile crack growth in tungsten inert gas (TIG) weldments of austenitic stainless steel specimens. The substantially greater yield strength of the weld metal relative to the base metal causes more plastic deformation in the base metal adjacent to the weld than in the weld metal. Accordingly, the analytical studies focused on the stress-strain interaction between the crack tip and the weld/base-metal interface. Experimental work involved tests using compact (tension) specimens of three different sizes and pipe bend experiments. The compact specimens were machined from a TIG weldment in Type 304 stainless steel plate. The pipe specimens were also TIG welded using the same welding procedures. Elastic-plastic finite element methods were used to model the experiments. In addition to the J-integral, different crack-tip integral parameters such as ΔT/sub p/* and J were evaluated. Also, engineering J-estimation methods were employed to predict the load-carrying capacity of the welded pipe with a circumferential through-wall crack under bending

  9. Risk-based high-throughput chemical screening and prioritization using exposure models and in vitro bioactivity assays

    International Nuclear Information System (INIS)

    Shin, Hyeong-Moo; Ernstoff, Alexi; Csiszar, Susan A.

    2015-01-01

    We present a risk-based high-throughput screening (HTS) method to identify chemicals for potential health concerns or for which additional information is needed. The method is applied to 180 organic chemicals as a case study. We first obtain information on how the chemical is used and identify relevant use scenarios (e.g., dermal application, indoor emissions). For each chemical and use scenario, exposure models are then used to calculate a chemical intake fraction, or a product intake fraction, accounting for chemical properties and the exposed population. We then combine these intake fractions with use scenario-specific estimates of chemical quantity to calculate daily intake rates (iR; mg/kg/day). These intake rates are compared to oral equivalent doses (OED; mg/kg/day), calculated from a suite of ToxCast in vitro bioactivity assays using in vitro-to-in vivo extrapolation and reverse dosimetry. Bioactivity quotients (BQs) are calculated as iR/OED to obtain estimates of potential impact associated with each relevant use scenario. Of the 180 chemicals considered, 38 had maximum iRs exceeding minimum OEDs (i.e., BQs > 1). For most of these compounds, exposures are associated with direct intake, food/oral contact, or dermal exposure. The method provides high-throughput estimates of exposure and important input for decision makers to identify chemicals of concern for further evaluation with additional information or more refined models

  10. High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

    KAUST Repository

    Koski, Kristie J.; Cha, Judy J.; Reed, Bryan W.; Wessells, Colin D.; Kong, Desheng; Cui, Yi

    2012-01-01

    A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

  11. Controlled assembly of organic whispering-gallery-mode microlasers as highly sensitive chemical vapor sensors.

    Science.gov (United States)

    Gao, Miaomiao; Wei, Cong; Lin, Xianqing; Liu, Yuan; Hu, Fengqin; Zhao, Yong Sheng

    2017-03-09

    We demonstrate the fabrication of organic high Q active whispering-gallery-mode (WGM) resonators from π-conjugated polymer by a controlled emulsion-solvent-evaporation method, which can simultaneously provide optical gain and act as an effective resonant cavity. By measuring the shift of their lasing modes on exposure to organic vapor, we successfully monitored the slight concentration variation in the chemical gas. These microlaser sensors demonstrated high detection sensitivity and good signal repeatability under continuous chemical gas treatments. The results offer an effective strategy to design miniaturized optical sensors.

  12. High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

    KAUST Repository

    Koski, Kristie J.

    2012-05-09

    A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

  13. Extracting chemical information from high-resolution Kβ X-ray emission spectroscopy

    Science.gov (United States)

    Limandri, S.; Robledo, J.; Tirao, G.

    2018-06-01

    High-resolution X-ray emission spectroscopy allows studying the chemical environment of a wide variety of materials. Chemical information can be obtained by fitting the X-ray spectra and observing the behavior of some spectral features. Spectral changes can also be quantified by means of statistical parameters calculated by considering the spectrum as a probability distribution. Another possibility is to perform statistical multivariate analysis, such as principal component analysis. In this work the performance of these procedures for extracting chemical information in X-ray emission spectroscopy spectra for mixtures of Mn2+ and Mn4+ oxides are studied. A detail analysis of the parameters obtained, as well as the associated uncertainties is shown. The methodologies are also applied for Mn oxidation state characterization of double perovskite oxides Ba1+xLa1-xMnSbO6 (with 0 ≤ x ≤ 0.7). The results show that statistical parameters and multivariate analysis are the most suitable for the analysis of this kind of spectra.

  14. 77 FR 66638 - The Standard on Process Safety Management of Highly Hazardous Chemicals; Extension of the Office...

    Science.gov (United States)

    2012-11-06

    ... Standard on Process Safety Management of Highly Hazardous Chemicals; Extension of the Office of Management...) approval of the information collection requirements specified in the Standard on Process Safety Management...: The Standard on Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119). OMB Number...

  15. Triggering the Chemical Instability of an Ionic Liquid under High Pressure.

    Science.gov (United States)

    Faria, Luiz F O; Nobrega, Marcelo M; Temperini, Marcia L A; Bini, Roberto; Ribeiro, Mauro C C

    2016-09-01

    Ionic liquids are an interesting class of materials due to their distinguished properties, allowing their use in an impressive range of applications, from catalysis to hypergolic fuels. However, the reactivity triggered by the application of high pressure can give rise to a new class of materials, which is not achieved under normal conditions. Here, we report on the high-pressure chemical instability of the ionic liquid 1-allyl-3-methylimidazolium dicyanamide, [allylC1im][N(CN)2], probed by both Raman and IR techniques and supported by quantum chemical calculations. Our results show a reaction occurring above 8 GPa, involving the terminal double bond of the allyl group, giving rise to an oligomeric product. The results presented herein contribute to our understanding of the stability of ionic liquids, which is of paramount interest for engineering applications. Moreover, gaining insight into this peculiar kind of reactivity could lead to the development of new or alternative synthetic routes to achieve, for example, poly(ionic liquids).

  16. Characterization of plutonium-bearing wastes by chemical analysis and analytical electron microscopy

    International Nuclear Information System (INIS)

    Behrens, R.G.; Buck, E.C.; Dietz, N.L.; Bates, J.K.; Van Deventer, E.; Chaiko, D.J.

    1995-09-01

    This report summarizes the results of characterization studies of plutonium-bearing wastes produced at the US Department of Energy weapons production facilities. Several different solid wastes were characterized, including incinerator ash and ash heels from Rocky Flats Plant and Los Alamos National Laboratory; sand, stag, and crucible waste from Hanford; and LECO crucibles from the Savannah River Site. These materials were characterized by chemical analysis and analytical electron microscopy. The results showed the presence of discrete PuO 2 PuO 2-x , and Pu 4 O 7 phases, of about 1μm or less in size, in all of the samples examined. In addition, a number of amorphous phases were present that contained plutonium. In all the ash and ash heel samples examined, plutonium phases were found that were completely surrounded by silicate matrices. Consequently, to achieve optimum plutonium recovery in any chemical extraction process, extraction would have to be coupled with ultrafine grinding to average particle sizes of less than 1 μm to liberate the plutonium from the surrounding inert matrix

  17. Physico-chemical studies of radiation effects in cells. Progress report, November 15, 1980-February 14, 1984

    International Nuclear Information System (INIS)

    Powers, E.L.

    1983-01-01

    The primary interest is investigating and understanding the chemical mechanisms involved in radiation-induced cellular damage. Most recently the perturbating devices have been metals which increase, in various ways and modes, the radiation sensitivity of several cell types. While the chief cell type has been the bacterial spore, chosen because of its biological inertness and its hardiness, allowing it to survive the unphysiological conditions of the physical chemist and, thus, inquiry into the free radical mechanisms involved very soon after energy absorption, recently vegetative cells have been introduced. A number of metals have been used and practically all of them sensitize - but to varying degrees. Straight biological techniques such as the measurement of cell survival under various conditions in the different cells have been used, as well as parallel experiments in pulse radiolysis to attack the specific leads in a chemical fashion suggested by the biology

  18. Chemically synthesized metal-oxide-metal segmented nanowires with high ferroelectric response

    International Nuclear Information System (INIS)

    Herderick, Edward D; Padture, Nitin P; Polomoff, Nicholas A; Huey, Bryan D

    2010-01-01

    A chemical synthesis method is presented for the fabrication of high-definition segmented metal-oxide-metal (MOM) nanowires in two different ferroelectric oxide systems: Au-BaTiO 3 -Au and Au-PbTiO 3 -Au. This method entails electrodeposition of segmented nanowires of Au-TiO 2 -Au inside anodic aluminum oxide (AAO) templates, followed by topotactic hydrothermal conversion of the TiO 2 segments into BaTiO 3 or PbTiO 3 segments. Two-terminal devices from individual MOM nanowires are fabricated, and their ferroelectric properties are measured directly, without the aid of scanning probe microscopy (SPM) methods. The MOM nanowire architecture provides high-quality end-on electrical contacts to the oxide segments, and allows direct measurement of properties of nanoscale volume, strain-free oxide segments. Unusually high ferroelectric responses, for chemically synthesized oxides, in these MOM nanowires are reported, and are attributed to the lack of residual strain in the oxides. The ability to measure directly the active properties of nanoscale volume, strain-free oxides afforded by the MOM nanowire architecture has important implications for fundamental studies of not only ferroelectric nanostructures but also nanostructures in the emerging field of multiferroics.

  19. Determination of chemical availability of cadmium and zinc in soils using inert soil moisture samplers.

    Science.gov (United States)

    Knight, B P; Chaudri, A M; McGrath, S P; Giller, K E

    1998-01-01

    A rapid method for extracting soil solutions using porous plastic soil-moisture samplers was combined with a cation resin equilibration based speciation technique to look at the chemical availability of metals in soil. Industrially polluted, metal sulphate amended and sewage sludge treated soils were used in our study. Cadmium sulphate amended and industrially contaminated soils all had > 65% of the total soil solution Cd present as free Cd2+. However, increasing total soil Cd concentrations by adding CdSO4 resulted in smaller total soil solution Cd. Consequently, the free Cd2+ concentrations in soil solutions extracted from these soils were smaller than in the same soil contaminated by sewage sludge addition. Amendment with ZnSO4 gave much greater concentrations of free Zn2+ in soil solutions compared with the same soil after long-term Zn contamination via sewage sludge additions. Our results demonstrate the difficulty in comparing total soil solution and free metal ion concentrations for soils from different areas with different physiochemical properties and sources of contamination. However, when comparing the same Woburn soil, Cd was much less available as Cd2+ in soil solution from the CdSO4 amended soils compared with soil contaminated by about 36 years of sewage sludge additions. In contrast, much more Zn was available in soil solution as free Zn2+ in the ZnSO4 amended soils compared with the sewage sludge treated soils.

  20. Industrial garnet

    Science.gov (United States)

    Olson, D.W.

    2013-01-01

    Garnet has been used as a gemstone since the Bronze Age. However, garnet’s angular fractures, relatively high hardness and specific gravity, chemical inertness and nontoxicity make it ideal for many industrial applications. It is also free of crystalline silica and can be recycled.

  1. Modification of silicon nitride and silicon carbide surfaces for food and biosensor applications

    NARCIS (Netherlands)

    Rosso, M.

    2009-01-01

    Silicon-rich silicon nitride (SixN4, x > 3) is a robust insulating material widely used for the coating of microdevices: its high chemical and mechanical inertness make it a material of choice for the reinforcement of fragile microstructures (e.g. suspended microcantilevers, micro-fabricated

  2. LANDFILLS FOR NON-HAZARDOUS WASTE AND INERT WASTE AND THEIR OPERATION CYCLE IN NEW SYSTEM OF THE WASTE MANAGEMENT

    OpenAIRE

    Joanna Kunc

    2017-01-01

    Until 2012, the chief method of disposing of municipal waste in Poland was by storing it on non-hazardous and inert waste landfills. The introduction of a new waste management system as well as new formal and legal requirements have forced changes in key documents related to landfill installations such as processing permits, landfill operation instructions and management instructions. The operation cycle has been disturbed, reducing considerably their operation time and leading to a premature...

  3. Physical-morphological and chemical changes leading to an increase in adhesion between plasma treated polyester fibres and a rubber matrix

    International Nuclear Information System (INIS)

    Krump, H.; Hudec, I.; Jasso, M.; Dayss, E.; Luyt, A.S.

    2006-01-01

    The effects of plasma treatment, used to increase adhesion strength between poly(ethylene terephtalate) (PET) fibres and a rubber matrix, were investigated and compared. Morphological changes as a result of atmospheric plasma treatment were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Wettability analysis using a surface energy evaluation system (SEE system) suggested that the plasma treated fibre was more wetting towards a polar liquid. When treated, these fibres showed a new lamellar crystallization, as shown by a new melting peak using differential scanning calorimetry (DSC). X-ray photoelectron spectroscopy (XPS) has been used to study the chemical effect of inert (argon), active and reactive (nitrogen and oxygen) microwave-plasma treatments of a PET surface. Reactive oxygen plasma treatment by a de-convolution method shows new chemical species that drastically alter the chemical reactivity of the PET surface. These studies have also shown that the surface population of chemical species formed after microwave-plasma treatment is dependent on the plasma gas. All these changes cause better adhesion strength of the PET fibres to the rubber matrix

  4. Porous SiO{sub 2} nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

    Energy Technology Data Exchange (ETDEWEB)

    Das, Indranee [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); De, Goutam, E-mail: gde@cgcri.res.in [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Hupa, Leena [Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Åbo (Finland); Vallittu, Pekka K. [Turku Clinical Biomaterials Centre—TCBC, University of Turku, FI-20520 Turku (Finland); Institute of Dentistry, University of Turku, Department of Biomaterials Science and City of Turku, Welfare Division, Turku (Finland)

    2016-05-01

    A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO{sub 2} nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

  5. Inert gas investigations of the Apollo 15 and 17 landing sites

    International Nuclear Information System (INIS)

    Jordan, J.L.

    1975-01-01

    The inert gas contents in size fractions of the following fines from the Apollo 15 site: 15071, 15501, 15511, 15421, and 15080 has been determined. In addition, the same for size fractions of fines 79221, 79241, and 79261 from depths of 0 to 2 cm, 2 to 7 cm, and 7 to 17 cm in a trench near Van Serg Crater at the Apollo 17 site was determined. The very low gas contents and lack of anticorrelation with grain diameter of 15421 suggests that these fines are undersaturated with respect to solar wind irradiation. The decrease in slope of the curves for gas concentration vs grain diameter of 15071 for successively heavier gases is interpreted to be the effects of the Rosiwal principle + comminution + agglutinate formation. Evidence for heavily irradiated (with respect to cosmic rays) zones deep within or beneath the regolith exists at both Apollo 15 and 17 landing sites. This may in part explain the ''missing'' cosmic ray record. Scatter between ''young'' and ''old'' age limits in 40 Ar vs 36 Ar plots exists for 15511, and the 3 trench fines from the Apollo 17 landing site. In the case of 15511 the observed ratios suggest that these may be the result of large impacts on the Apennine Front contributing material to the site where 15511 was collected. The observed 40 Ar/ 36 Ar ratios in the trench fines may be the result of excavation of materials with high 40 Ar/ 36 Ar ratios during the Van Serg event. The low apparent 40 K-- 40 Ar ages of the Apollo 15 fines are interpreted to be the result of addition of young 40 K-- 40 Ar age material (less than 1.8 by) from Autolycus and Aristillus, two large craters north of the site, to the older (3.3 by) mare materials

  6. Hydrophobic and Metallophobic Surfaces: Highly Stable Non-wetting Inorganic Surfaces Based on Lanthanum Phosphate Nanorods.

    Science.gov (United States)

    Sankar, Sasidharan; Nair, Balagopal N; Suzuki, Takehiro; Anilkumar, Gopinathan M; Padmanabhan, Moothetty; Hareesh, Unnikrishnan Nair S; Warrier, Krishna G

    2016-03-09

    Metal oxides, in general, are known to exhibit significant wettability towards water molecules because of the high feasibility of synergetic hydrogen-bonding interactions possible at the solid-water interface. Here we show that the nano sized phosphates of rare earth materials (Rare Earth Phosphates, REPs), LaPO4 in particular, exhibit without any chemical modification, unique combination of intrinsic properties including remarkable hydrophobicity that could be retained even after exposure to extreme temperatures and harsh hydrothermal conditions. Transparent nanocoatings of LaPO4 as well as mixture of other REPs on glass surfaces are shown to display notable hydrophobicity with water contact angle (WCA) value of 120° while sintered and polished monoliths manifested WCA greater than 105°. Significantly, these materials in the form of coatings and monoliths also exhibit complete non-wettability and inertness towards molten metals like Ag, Zn, and Al well above their melting points. These properties, coupled with their excellent chemical and thermal stability, ease of processing, machinability and their versatile photo-physical and emission properties, render LaPO4 and other REP ceramics utility in diverse applications.

  7. New high performance nanoadditives for photocatalytic concrete: synthesis and study

    Directory of Open Access Journals (Sweden)

    FALIKMAN Vyacheslav Ruvimovich

    2015-02-01

    Full Text Available Nanotechnologies open up broad prospects for the creation of nanocatalysts, which are being more and more used in solving many problems associated with the protection of environment. Their behavior is directly related to the unique physical and chemical properties that are provided by quantum size effects, as well as the large specific surface area. It is known that the presence of photo catalysts in the construction segment of nanomaterials is becoming more prominent. One of the most significant achievements of the last years are photo catalytic active cement composites, including cements and concretes produced with the use of nanoparticles of titanium dioxide TiO₂ sensibilized through a nanotechnology . Currently they are widely used in practice to produce selfcleaning structures and to make clean an air of megacities. Further research in the field of development of new high-performance photo catalysts based on TiO₂ nanoparticles seems to be very relevant, because such R&D could significantly improve the technical characteristics of photo catalytic cements and concrete. In this paper an improved method to produce photo catalysts has been proposed. New synthesized products are based on TiO₂ nanoparticles applied on different inert carriers, including nanosilica. It was showed that these products can be used as a high performance photo catalyst in cement and cement-gypsum composites suitable for the onversion processes of nitric oxide and volatile organic substances, and air purification. It was determined that performance of the cementitious composites containing synthesized samples is 1,5…3,0 times higher than that for the commercial sample of the nanotitanium dioxide. The use of mechanical mixture of nanotitanium dioxide and inert supports is less effective and subjected to the «dilution law», in general.

  8. High-Performance Black Multicrystalline Silicon Solar Cells by a Highly Simplified Metal-Catalyzed Chemical Etching Method

    KAUST Repository

    Ying, Zhiqin

    2016-05-20

    A wet-chemical surface texturing technique, including a two-step metal-catalyzed chemical etching (MCCE) and an extra alkaline treatment, has been proven as an efficient way to fabricate high-efficiency black multicrystalline (mc) silicon solar cells, whereas it is limited by the production capacity and the cost cutting due to the complicated process. Here, we demonstrated that with careful control of the composition in etching solution, low-aspect-ratio bowl-like nanostructures with atomically smooth surfaces could be directly achieved by improved one-step MCCE and with no posttreatment, like alkali solution. The doublet surface texture of implementing this nanobowl structure upon the industrialized acidic-textured surface showed concurrent improvement in optical and electrical properties for realizing 18.23% efficiency mc-Si solar cells (156 mm × 156 mm), which is sufficiently higher than 17.7% of the solely acidic-textured cells in the same batch. The one-step MCCE method demonstrated in this study may provide a cost-effective way to manufacture high-performance mc-Si solar cells for the present photovoltaic industry. © 2016 IEEE.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  10. Mechanical and chemical responses of low-velocity impacted RDX and HMX explosive powders

    Science.gov (United States)

    Wu, Yanqing; Guo, Hongfu; Huang, Fenglei; Bao, Xiaowei; Explosion; damage Team

    2017-06-01

    The experimental analyses of mechanical and chemical responses of RDX and HMX particles were performed based on the optimized drop-weight experimental system equipped with the High-Speed Camera (HSC). It has been found that Jetting phenomenon observed by HSC is the result of the energy released by gaseous products, which push the pulverized or melted explosives to splash radially. Jetting is the only and the most obvious difference between reactive and inert particles prior to combustion so that jetting can be regarded as the sign of ignition. Area expansion velocity, jetting velocity, and flame propagation velocity have been estimated via image processing, making it possible to characterize mechanical deformation and violence of reaction of each stage. Hot-spots coalescence promotes flame propagation whose velocity reflects the violence of deflagration reaction. Jetting appearance time can be used to determine time-to-ignition more accurately than other ways. For RDX, molten phase plays an important role to the formation of the hot-spots. Multiple particles experienced more severe burning reactions than an individual particle. China National Nature Science Foundation (11572045), ``Science Challenging Program'' (JCKY2016212A501),opening fund from Safety ammunition research and Development Center (RMC2015B03).

  11. Use of spectroscopic techniques for the chemical analysis of biomorphic silicon carbide ceramics

    International Nuclear Information System (INIS)

    Pavon, J.M. Cano; Alonso, E. Vereda; Cordero, M.T. Siles; Torres, A. Garcia de; Lopez-Cepero, J.M.

    2005-01-01

    Biomorphic silicon carbide ceramics are a new class of materials prepared by several complex processing steps including pre-processing (shaping, drying, high-temperature pyrolysis in an inert atmosphere) and reaction with liquid silicon to obtain silicon-carbide. The results of industrial process of synthesis (measured by the SiC content) must be evaluated by means of fast analytical methods. In the present work, diverse samples of biomorphic ceramics derived from wood are studied for to evaluate the capability of the different analytical techniques (XPS, LIBS, FT-IR and also atomic spectroscopy applied to previously dissolved samples) for the analysis of these materials. XPS and LIBS gives information about the major components, whereas XPS and FT-IR can be used to evaluate the content of SiC. On the other hand, .the use of atomic techniques (as ICP-MS and ETA-AAS) is more adequate for the analysis of metal ions, specially at trace level. The properties of ceramics depend decisively of the content of chemical elements. Major components found were C, Si, Al, S, B and Na in all cases. Previous dissolution of the samples was optimised by acid attack in an oven under microwave irradiation

  12. Ingestão de ração e comportamento de larvas de pacu em resposta a estímulos químicos e visuais Diet ingestion rate and pacu larvae behavior in response to chemical and visual stimuli

    Directory of Open Access Journals (Sweden)

    Marcelo Borges Tesser

    2006-10-01

    Full Text Available Este estudo foi realizado com o objetivo de comparar a influência dos estímulos visual e/ou químico de náuplios de Artemia e de dieta microencapsulada sobre a taxa de ingestão da dieta microencapusulada por larvas de pacu Piaractus mesopotamicus. Utilizou-se um esquema fatorial 7 x 4 (estímulos e idades com duas repetições. Verificou-se efeito da idade das larvas e dos estímulos, mas não houve efeito para a interação idade ´ estímulos. O estímulo químico da Artemia e ambos os estímulos da Artemia resultaram em maior taxa de ingestão de dieta inerte. Resultado intermediário foi obtido com o estímulo visual da dieta microencapsulada. O estímulo químico, em comparação ao estímulo visual da Artemia, resultou em maiores taxas de ingestão da dieta. Com o aumento da idade, houve incremento na taxa de ingestão. Os estímulos visual e químico dos náuplios e o estímulo visual da ração aumentaram a ingestão de dieta inerte por larvas de pacu. Náuplios de Artemia devem ser oferecidos antes do fornecimento da dieta inerte, pois podem auxiliar no processo de transição alimentar. Os resultados deste trabalho apontaram novas possibilidades de estudos com larvas de peixes neotropicais visando a substituição precoce do alimento vivo para o inerte.The effect of visual, chemical and the combination of both stimuli from Artemia nauplii and from microencapsulated diet on dry diet ingestion by pacu Piaractus mesopotamicus larvae was evaluated in this research. The experiment was analyzed as a 7 x 4 factorial arrangement (seven stimuli and four ages with two replicates. It was observed effect of larvae age and stimuli, but no interaction (age ´ stimuli was observed. The chemical effect from Artemia and both effects from Artemia resulted in higher ingestion rates. An intermediary result was obtained with visual effect from microencapsulated diet. The chemical stimulus from Artemia resulted in higher ingestion rates than that

  13. Residual insecticides, inert dusts and botanicals for the protection of durable stored products against pest infestation in developing countries

    Directory of Open Access Journals (Sweden)

    Obeng-Ofori, D.

    2010-09-01

    Full Text Available Insect pests associated with durable grains and processed food cause considerable quantitative and qualitative losses throughout the world. Insect infestation can occur just prior to harvest, during storage in traditional storage structures, cribs, metal or concrete bins, and in warehouses, food handling facilities, retail grocery stores as well as in-transit. Many tools are available for managing insects associated with grains and processed food. Although pest management strategies are changing to meet consumer’s demand for food free of insecticide residues, address concerns about safety of insecticides to humans, delay insecticide resistance development in insects and comply with stricter insecticide regulations, the use of synthetic residual insecticides will continue to be a major component of stored-product pest management programmes. Selective use of residual insecticides requires a through understanding and evaluation of risks, costs and benefits. The use of plant and inert materials may be a safe, cost-effective and environmentally friendly method of grain preservation against pest infestation among low-resource poor farmers who store small amounts of grains. There is a dearth of information on the use of plant materials by rural farmers in Africa for stored-product protection. The most promising candidate plant materials for future utilization as grain protectants are Azadirachta, Acorus, Chenopodium, Eucalyptus, Mentha, Ocimum, Piper and Tetradenia together with vegetable oils from various sources. Neem is the only plant from which several commercial products have been developed worldwide. However, unlike synthetic insecticides these alternatives often do not provide effective or rapid suppression of pest populations and may not be effective against all species of pests. These alternatives are also more expensive than synthetic insecticides, and have not been tested extensively under field conditions in the tropics. This paper

  14. 6 CFR 27.205 - Determination that a chemical facility “presents a high level of security risk.”

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Determination that a chemical facility âpresents... SECURITY, OFFICE OF THE SECRETARY CHEMICAL FACILITY ANTI-TERRORISM STANDARDS Chemical Facility Security Program § 27.205 Determination that a chemical facility “presents a high level of security risk.” (a...

  15. High-Throughput Dietary Exposure Predictions for Chemical Migrants from Food Packaging Materials

    Science.gov (United States)

    United States Environmental Protection Agency researchers have developed a Stochastic Human Exposure and Dose Simulation High -Throughput (SHEDS-HT) model for use in prioritization of chemicals under the ExpoCast program. In this research, new methods were implemented in SHEDS-HT...

  16. TOXIC METALS IN THE ENVIRONMENT: THERMODYNAMIC CONSIDERATIONS FOR POSSIBLE IMMOBILIZATION STRATEGIES FOR PB, CD, AS, AND HG

    Science.gov (United States)

    The contamination of soils by toxic metals is a widespread, serious problem that demands immediate action either by removal or immobilization, which is defined as a process which puts the metal into a chemical form, probably as a mineral, which will be inert and highly insoluble ...

  17. Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalyst

    Science.gov (United States)

    Gao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, Yuhan

    2017-10-01

    Although considerable progress has been made in carbon dioxide (CO2) hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The oxygen vacancies on the In2O3 surfaces activate CO2 and hydrogen to form methanol, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane number. The proximity of these two components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Moreover, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.

  18. Effects of high-pressure argon and nitrogen treatments on respiration, browning and antioxidant potential of minimally processed pineapples during shelf life.

    Science.gov (United States)

    Wu, Zhi-shuang; Zhang, Min; Wang, Shao-jin

    2012-08-30

    High-pressure (HP) inert gas processing causes inert gas and water molecules to form clathrate hydrates that restrict intracellular water activity and enzymatic reactions. This technique can be used to preserve fruits and vegetables. In this study, minimally processed (MP) pineapples were treated with HP (∼10 MPa) argon (Ar) and nitrogen (N) for 20 min. The effects of these treatments on respiration, browning and antioxidant potential of MP pineapples were investigated after cutting and during 20 days of storage at 4 °C. Lower respiration rate and ethylene production were found in HP Ar- and HP N-treated samples compared with control samples. HP Ar and HP N treatments effectively reduced browning and loss of total phenols and ascorbic acid and maintained antioxidant capacity of MP pineapples. They did not cause a significant decline in tissue firmness or increase in juice leakage. HP Ar treatments had greater effects than HP N treatments on reduction of respiration rate and ethylene production and maintenance of phenolic compounds and DPPH(•) and ABTS(•+) radical-scavenging activities. Both HP Ar and HP N processing had beneficial effects on MP pineapples throughout 20 days of storage at 4 °C. Copyright © 2012 Society of Chemical Industry.

  19. Co-disposal of industrial wastes to obtain an inert material for environmental reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Polcaro, A.M.; Palams, S.; Mascia, M.; Renoldi, F. [Cagliari Univ., Cagliari (Italy). Dipt. di Ingegneria Chimica e dei Materiali

    2000-02-01

    The present work deals with the treatment of red mud from Eurallumina Bayer plant with gypsum, in order to obtain an inert which might be disposed without risk. The proposed process has particular concern in the local contest in which the Bayer plant is located. The paper compares the characteristics of the effluents obtained leaching with water, beds of either red mud coming from the thickening filters of the Bayer plant (RMF) or from the holding ponds (RMP) or their mixtures with gypsum. The results obtained up to now show that the process is able to lower ph at values near 9, which is stable to further leaching runs. Also the physical characteristics of the resulting material are enhanced, in terms of both particle size distribution and hydraulic permeability. The addition of 10% sandy soil is sufficient to give permeability in the order of 10{sup -4} cm/s, which is typical od sandy soil. [Italian] Il lavoro analizza il trattamento di fango rosso del processo Bayer con gesso allo scopo di ottenere un materiale inerte, che possa essere smaltito senza particolari precauzioni. Il trattamento proposto puo' avere una certa rilevanza nel contesto territoriale in cui l'impianto di produzione e' inserito. In particolare sono state esaminate e confrontate le caratteristiche degli effluenti da prove di liscivazione con acqua di letti costituiti sia da fango prelevato direttamente dai filtri di ispessimento, che da fango prelevato dal bacino di lagunaggio. I risultati mostrano che il processo e' in grado di abbassare il pH del fango ad un valore intorno a 9, che si mantiene stabile alla liscivazione, anche quando la salinita' della massa ha raggiunto valori molto bassi. Il processo consente inoltre di migliorare le caratteristiche fisiche del materiale, sia in termini di granulometria, che si sposta verso le frazioni piu' grosse, che di permeabilita'. Una miscelazione con il 10% di terreno sabbioso e' sufficiente a conferire al

  20. Ceramic cutting tools materials, development and performance

    CERN Document Server

    Whitney, E Dow

    1994-01-01

    Interest in ceramics as a high speed cutting tool material is based primarily on favorable material properties. As a class of materials, ceramics possess high melting points, excellent hardness and good wear resistance. Unlike most metals, hardness levels in ceramics generally remain high at elevated temperatures which means that cutting tip integrity is relatively unaffected at high cutting speeds. Ceramics are also chemically inert against most workmetals.

  1. The removal of gaseous impurities from the primary circuit in high temperature reactors with cerium-mischmetal-getters

    International Nuclear Information System (INIS)

    Heinen, R.

    1986-11-01

    The use of getters to remove tritium and other gaseous impurities (especially H 2 , N 2 and CO) from helium circuits in nuclear reactors has been investigated. The loading capcity of beds, containing small cerium-mischmetal chips has been tested for several typical conditions. The results show that it is possible to use getters to purify inert gas streams for given boundary conditions. High CO-levels, however, lead to a poisoning (passivation) of the getter material. The effect of poisoning is cumulative. A mathematical model describes the behavior of CO in this kind of getter. Safety tests under possible accident conditions were made with the highly reactive cerium-mischmetal chips. The results show that there isn't a critical problem in using this material in the form of a chemical reactive getter bed near a nuclear reactor in the investigated range of accident conditions. (orig.) [de

  2. Influence of chemical agents on the surface area and porosity of active carbon hollow fibers

    Directory of Open Access Journals (Sweden)

    LJILJANA M. KLJAJEVIĆ

    2011-09-01

    Full Text Available Active carbon hollow fibers were prepared from regenerated polysulfone hollow fibers by chemical activation using: disodium hydrogen phosphate 2-hydrate, disodium tetraborate 10-hydrate, hydrogen peroxide, and diammonium hydrogen phosphate. After chemical activation fibers were carbonized in an inert atmosphere. The specific surface area and porosity of obtained carbons were studied by nitrogen adsorption–desorption isotherms at 77 K, while the structures were examined with scanning electron microscopy and X-ray diffraction. The activation process increases these adsorption properties of fibers being more pronounced for active carbon fibers obtained with disodium tetraborate 10-hydrate and hydrogen peroxide as activator. The obtained active hollow carbons are microporous with different pore size distribution. Chemical activation with phosphates produces active carbon material with small surface area but with both mesopores and micropores. X-ray diffraction shows that besides turbostratic structure typical for carbon materials, there are some peaks which indicate some intermediate reaction products when sodium salts were used as activating agent. Based on data from the electrochemical measurements the activity and porosity of the active fibers depend strongly on the oxidizing agent applied.

  3. Chemical and Thermodynamic Properties at High Temperatures: A Symposium

    Science.gov (United States)

    Walker, Raymond F.

    1961-01-01

    This book contains the program and all available abstracts of the 90' invited and contributed papers to be presented at the TUPAC Symposium on Chemical and Thermodynamic Properties at High Temperatures. The Symposium will be held in conjunction with the XVIIIth IUPAC Congress, Montreal, August 6 - 12, 1961. It has been organized, by the Subcommissions on Condensed States and on Gaseous States of the Commission on High Temperatures and Refractories and by the Subcommission on Experimental Thermodynamics of the Commission on Chemical Thermodynamics, acting in conjunction with the Organizing Committee of the IUPAC Congress. All inquiries concerning participation In the Symposium should be directed to: Secretary, XVIIIth International Congress of Pure and Applied Chemistry, National Research Council, Ottawa, 'Canada. Owing to the limited time and facilities available for the preparation and printing of the book, it has not been possible to refer the proofs of the abstracts to the authors for checking. Furthermore, it has not been possible to subject the manuscripts to a very thorough editorial examination. Some obvious errors in the manuscripts have been corrected; other errors undoubtedly have been introduced. Figures have been redrawn only when such a step was essential for reproduction purposes. Sincere apologies are offered to authors and readers for any errors which remain; however, in the circumstances neither the IUPAC Commissions who organized the Symposium, nor the U. S. Government Agencies who assisted in the preparation of this book can accept responsibility for the errors.

  4. Chemically synthesized metal-oxide-metal segmented nanowires with high ferroelectric response

    Energy Technology Data Exchange (ETDEWEB)

    Herderick, Edward D; Padture, Nitin P [Department of Materials Science and Engineering, Center for Emergent Materials, Ohio State University, Columbus, OH 43210 (United States); Polomoff, Nicholas A; Huey, Bryan D, E-mail: padture.1@osu.edu [Department of Chemical, Materials, and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States)

    2010-08-20

    A chemical synthesis method is presented for the fabrication of high-definition segmented metal-oxide-metal (MOM) nanowires in two different ferroelectric oxide systems: Au-BaTiO{sub 3}-Au and Au-PbTiO{sub 3}-Au. This method entails electrodeposition of segmented nanowires of Au-TiO{sub 2}-Au inside anodic aluminum oxide (AAO) templates, followed by topotactic hydrothermal conversion of the TiO{sub 2} segments into BaTiO{sub 3} or PbTiO{sub 3} segments. Two-terminal devices from individual MOM nanowires are fabricated, and their ferroelectric properties are measured directly, without the aid of scanning probe microscopy (SPM) methods. The MOM nanowire architecture provides high-quality end-on electrical contacts to the oxide segments, and allows direct measurement of properties of nanoscale volume, strain-free oxide segments. Unusually high ferroelectric responses, for chemically synthesized oxides, in these MOM nanowires are reported, and are attributed to the lack of residual strain in the oxides. The ability to measure directly the active properties of nanoscale volume, strain-free oxides afforded by the MOM nanowire architecture has important implications for fundamental studies of not only ferroelectric nanostructures but also nanostructures in the emerging field of multiferroics.

  5. Chemical influence on the hydro-mechanical behaviour of high-density bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, E.; Romero, E.; Lioret, A. [Technical Univ. of Catalonia UPC, Barcelona (Spain); Musso, G. [Politecnico di Torino, Torino (Italy)

    2005-07-01

    In radioactive waste disposal schemes, during the operational period of clay barriers, solute transport an d thermal gradients may alter the solute concentration of pore water. These induced changes have important consequences on hydro-mechanical properties and microstructural alterations (mineral composition and pore size distribution changes) of the clay barrier. Chemically induced changes originated by different imbibition fluids and soil mineral compositions have been a subject with a long research tradition. These researches have been mainly focused on the behaviour of reconstituted soils starting from slurry and saturated wit h saline solutions at elevated concentrations, where hydro-mechanical changes (soil compressibility and water permeability changes) are clearly detected. In contrast, available information concerning the response of high-density clays subjected to chemically induced actions with a wide range of pore solution concentrations is very limited in spite of its practical relevance to environmental geotechnics. This situation has been caused, at least in part, by the difficulties in detecting important hydro-mechanical changes when clays with low water storage capacity have been used. Nevertheless, this paper will demonstrate that even in the case of high-density fabrics, considerable changes can be observed when high-activity clays (bentonites) are imbibed with different pore fluid compositions. (authors)

  6. High-resolution chemical imaging of gold nanoparticles using hard x-ray ptychography

    DEFF Research Database (Denmark)

    Hoppe, R.; Reinhardt, J.; Hofmann, G.

    2013-01-01

    We combine resonant scattering with (ptychographic) scanning coherent diffraction microscopy to determine the chemical state of gold nanoparticles with high spatial resolution. Ptychographic images of the sample are recorded for a series of energies around the gold L3 absorption edge. From these ...

  7. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.; Smith, Casey; Hussain, Muhammad Mustafa

    2014-01-01

    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.

    2014-05-15

    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High-pressure resistivity technique for quasi-hydrostatic compression experiments.

    Science.gov (United States)

    Rotundu, C R; Ćuk, T; Greene, R L; Shen, Z-X; Hemley, Russell J; Struzhkin, V V

    2013-06-01

    Diamond anvil cell techniques are now well established and powerful methods for measuring materials properties to very high pressure. However, high pressure resistivity measurements are challenging because the electrical contacts attached to the sample have to survive to extreme stress conditions. Until recently, experiments in a diamond anvil cell were mostly limited to non-hydrostatic or quasi-hydrostatic pressure media other than inert gases. We present here a solution to the problem by using focused ion beam ultrathin lithography for a diamond anvil cell loaded with inert gas (Ne) and show typical resistivity data. These ultrathin leads are deposited on the culet of the diamond and are attaching the sample to the anvil mechanically, therefore allowing for measurements in hydrostatic or nearly hydrostatic conditions of pressure using noble gases like Ne or He as pressure transmitting media.

  10. Validation of myocardial blood flow estimation with nitrogen-13 ammonia PET by the argon inert gas technique in humans

    International Nuclear Information System (INIS)

    Kotzerke, J.; Glatting, G.; Neumaier, B.; Reske, S.N.; Hoff, J. van den; Hoeher, M.; Woehrle, J. n

    2001-01-01

    We simultaneously determined global myocardial blood flow (MBF) by the argon inert gas technique and by nitrogen-13 ammonia positron emission tomography (PET) to validate PET-derived MBF values in humans. A total of 19 patients were investigated at rest (n=19) and during adenosine-induced hyperaemia (n=16). Regional coronary artery stenoses were ruled out by angiography. The argon inert gas method uses the difference of arterial and coronary sinus argon concentrations during inhalation of a mixture of 75% argon and 25% oxygen to estimate global MBF. It can be considered as valid as the microspheres technique, which, however, cannot be applied in humans. Dynamic PET was performed after injection of 0.8±0.2 GBq 13 N-ammonia and MBF was calculated applying a two-tissue compartment model. MBF values derived from the argon method at rest and during the hyperaemic state were 1.03±0.24 ml min -1 g -1 and 2.64±1.02 ml min -1 g -1 , respectively. MBF values derived from ammonia PET at rest and during hyperaemia were 0.95±0.23 ml min -1 g -1 and 2.44±0.81 ml min -1 g -1 , respectively. The correlation between the two methods was close (y=0.92x+0.14, r=0.96; P 13 N-ammonia PET. (orig.)

  11. Method for extending the useful shelf-life of refrigerated red blood cells by flushing with inert gas

    Science.gov (United States)

    Bitensky, Mark W.; Yoshida, Tatsuro

    1997-01-01

    Method using oxygen removal for extending the useful shelf-life of refrigerated red blood cells. A cost-effective, 4.degree. C. storage procedure that preserves red cell quality and prolongs post-transfusion in vivo survival is described. Preservation of adenosine triphosphate levels and reduction in hemolysis and in membrane vesicle production of red blood cells stored at 4.degree. C. for prolonged periods of time is achieved by removing oxygen therefrom at the time of storage; in particular, by flushing with an inert gas. Adenosine triphosphate levels of the stored red blood cells are boosted in some samples by addition of ammonium phosphate.

  12. Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

    Directory of Open Access Journals (Sweden)

    Shunsuke Asahina

    2014-11-01

    Full Text Available Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in york-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the york-shell materials: (i resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii sample preparation for observing internal structures; and (iii X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

  13. Physical and chemical characterization of airborne particles from welding operations in automotive plants.

    Science.gov (United States)

    Dasch, Jean; D'Arcy, James

    2008-07-01

    Airborne particles were characterized from six welding operations in three automotive plants, including resistance spot welding, metal inert gas (MIG) welding and tungsten inert gas (TIG) welding of aluminum and resistance spot welding, MIG welding and weld-through sealer of galvanized steel. Particle levels were measured throughout the process area to select a sampling location, followed by intensive particle sampling over one working shift. Temporal trends were measured, and particles were collected on filters to characterize their size and chemistry. In all cases, the particles fell into a bimodal size distribution with very large particles >20 mum in diameter, possibly emitted as spatter or metal expulsions, and very small particles about 1 mum in diameter, possibly formed from condensation of vaporized metal. The mass median aerodynamic diameter was about 1 mum, with only about 7% of the particle mass present as ultrafine particles welding particles could be accounted for by chemical analysis, with the remainder possibly present as oxygen. Predominant species were organic carbon, elemental carbon, iron, and aluminum. More than 80% of the particle mass could be accounted for from steel welding, primarily present as iron, organic carbon, zinc, and copper. Particle concentrations and elemental concentrations were compared with allowable concentrations as recommended by the Occupational Safety and Health Administration and the American Conference of Governmental Industrial Hygienists. In all cases, workplace levels were at least 11 times lower than recommended levels.

  14. The effect of electrode vertex angle on automatic tungsten-inert-gas welds for stainless steel 304L plates

    International Nuclear Information System (INIS)

    Maarek, V.; Sharir, Y.; Stern, A.

    1980-03-01

    The effect of electrode vertex angle on penetration depth and weld bead width, in automatic tungsten-inert-gas (TIG) dcsp bead-on-plate welding with different currents, has been studied for stainless steel 304L plates 1.5 mm and 8 mm thick. It has been found that for thin plates, wider and deeper welds are obtained when using sharper electrodes while, for thick plates, narrower and deeper welds are produced when blunt electrodes (vertex angle 180 deg) are used. An explanation of the results, based on a literature survey, is included

  15. Method for preparing high cure temperature rare earth iron compound magnetic material

    Science.gov (United States)

    Huang, Yuhong; Wei, Qiang; Zheng, Haixing

    2002-01-01

    Insertion of light elements such as H,C, or N in the R.sub.2 Fe.sub.17 (R=rare earth metal) series has been found to modify the magnetic properties of these compounds, which thus become prospective candidates for high performance permanent magnets. The most spectacular changes are increases of the Curie temperature, T.sub.c, of the magnetization, M.sub.s, and of coercivity, H.sub.c, upon interstitial insertion. A preliminary product having a component R--Fe--C,N phase is produced by a chemical route. Rare earth metal and iron amides are synthesized followed by pyrolysis and sintering in an inert or reduced atmosphere, as a result of which, the R--Fe--C,N phases are formed. Fabrication of sintered rare earth iron nitride and carbonitride bulk magnet is impossible via conventional process due to the limitation of nitridation method.

  16. Inert powders alone or in combination with neem oil for controlling Spodoptera eridania and Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae

    OpenAIRE

    Kelly Christiane Constanski Silva; Janaina Zorzetti; Patricia Helena Santoro; Adriano Thibes Hoshino; Pedro Manuel Oliveira Janeiro Neves

    2016-01-01

    Laboratory studies was carry out to evaluated the potential of inert powders: bentonite, kaolin and diatomaceous earth (DE) applied as dust and aqueous suspension alone and associated with neem oil to the control Spodoptera eridania and Spodoptera frugiperda second instar larvae. In dust applications, 100% mortality of S. eridania, at the concentrations of 1.5 and 2.0 grams of bentonite, and 93.3% of S. frugiperda, at the concentration of 2.0 g were observed. DE at the height concentration (2...

  17. Rapid and highly efficient growth of graphene on copper by chemical vapor deposition of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, Nicola, E-mail: nicola.lisi@enea.it [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Buonocore, Francesco; Dikonimos, Theodoros; Leoni, Enrico [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Faggio, Giuliana; Messina, Giacomo [Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Università “Mediterranea” di Reggio Calabria, 89122 Reggio Calabria (Italy); Morandi, Vittorio; Ortolani, Luca [CNR-IMM Bologna, Via Gobetti 101, 40129 Bologna (Italy); Capasso, Andrea [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy)

    2014-11-28

    The growth of graphene by chemical vapor deposition on metal foils is a promising technique to deliver large-area films with high electron mobility. Nowadays, the chemical vapor deposition of hydrocarbons on copper is the most investigated synthesis method, although many other carbon precursors and metal substrates are used too. Among these, ethanol is a safe and inexpensive precursor that seems to offer favorable synthesis kinetics. We explored the growth of graphene on copper from ethanol, focusing on processes of short duration (up to one min). We investigated the produced films by electron microscopy, Raman and X-ray photoemission spectroscopy. A graphene film with high crystalline quality was found to cover the entire copper catalyst substrate in just 20 s, making ethanol appear as a more efficient carbon feedstock than methane and other commonly used precursors. - Highlights: • Graphene films were grown by fast chemical vapor deposition of ethanol on copper. • High-temperature/short-time growth produced highly crystalline graphene. • The copper substrate was entirely covered by a graphene film in just 20 s. • Addition of H{sub 2} had a negligible effect on the crystalline quality.

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

    Directory of Open Access Journals (Sweden)

    Ana Amélia Rodrigues

    2013-02-01

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

  19. Influence of physio-chemical forms on transfer

    International Nuclear Information System (INIS)

    Oughton, D.H.; Salbu, B.

    1994-01-01

    The transfer and mobility of radionuclides within an ecosystem will be dependant on the physico-chemical forms of the deposited radionuclides. After a short summary of the influence of speciation and source term on the behaviour of anthropogenic radionuclides in aquatic and terrestrial systems, this paper focuses on appropriate sampling and analytical techniques that are applicable for speciation purposes. Particular emphasis is given to the significance of fuel particles in the releases from the Chernobyl reactor and, as an example of the application of the discussed techniques, results are presented from studies on 137 Cs and 90 Sr in soils collected from Nordic countries, and compared with results from soils collected in the SUS. The topics addressed include inhomogeneous deposition, the vertical distribution of radionuclides in soils, the use of sequential extraction to study the association of radionuclides with soil components, the use of NH 4 Ac extraction to distinguish between the mobile or labile fraction and the inert fraction of radionuclides in soils, aggregated transfer factors, and comparison of the distribution of radionuclides with naturally occurring stable isotopes. (orig.)

  20. Microstructure and erosion characteristic of nodular cast iron surface modified by tungsten inert gas

    International Nuclear Information System (INIS)

    Abboud, Jaafar Hadi

    2012-01-01

    Highlights: ► Local surface melting. ► Significant improvement in erosion resistance. ► The ductile behaviour was found. -- Abstract: The surface of nodular cast iron has been melted and rapidly solidified by Tungsten Inert Gas (TIG) process to produce a chilled structure of high hardness and better erosion resistance. Welding currents of magnitude 100, 150, and 200 A at a constant voltage of 72 have been used to melt the surface of nodular cast iron. Microstructural characterization, hardness measurements, and erosion wear tests have been performed on these modified surfaces as well as on the untreated material. Microstructural characterization has shown that surface melting resulted in complete or partial dissolution of the graphite nodules and resolidification of primary austenite dendrites, which undergo further decomposition into ferrite and cementite, and interdendritic of acicular eutectic; their microhardness measured across the melted depth ranged between 600 and 800 Hv. The scale of the dendrites and the interdendritic eutectic became coarser when a higher current is used. The results also indicated that remelting process by TIG improved erosion resistance by three to four times. Eroded surface observations of the as-received and TIG melted samples showed a ductile behavior with a maximum erosion rate at 30°. The fine microstructures obtained by the rapid cooling and the formation of a large amount of eutectic cementite instead of the graphite have contributed greatly to the plastic flow and consequently to the better erosion resistance of the TIG surface melted samples.