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Sample records for fuel dissolver solution

  1. Simultaneous measurements of plutonium and uranium in spent-fuel dissolver solutions

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.K. [Los Alamos National Lab., NM (United States); Kuno, T.; Kitagawa, O.; Sato, S.; Kurosawa, A.; Kuno, Y. [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan)

    1997-11-01

    The authors have studied the isotope dilution gamma-ray spectrometry (IDGS) technique for simultaneous measurements of elemental concentrations and isotopic compositions for both plutonium and uranium in input spent-fuel dissolver solutions at a reprocessing plant. The technique under development includes both sample preparation and analysis methods. For simultaneous measurements of both plutonium and uranium, a critical issue is to develop a new method to keep both plutonium and uranium in the sample after they are separated from fission products. Furthermore, it is equally important to improve the analysis method so that the precision and accuracy of the plutonium analysis remain unaffected while uranium is retained in the sample. To keep both plutonium and uranium in the sample for simultaneous measurements, extraction chromatography is being studied and shows promise to achieve the goal of cosegregation of the plutonium and uranium. The technique uses U/TEVA{center_dot}Spec resin to separate fission products and recover both uranium and plutonium in the resin from dissolver solutions for subsequent measuring using high-resolution gamma-ray spectrometry. Owing to the fact that the U/Pu ratio is altered during the fission product separation phase, it is necessary to develop a method which could accurately correct for this effect. Such a method was developed using the unique decay properties of {sup 241}Pu to {sup 237}U and shows considerable promise in allowing for accurate determination of the {sup 235}U concentrations before the chemical extraction.

  2. Reconstruction of Spent Fuel Dissolver Critical Assembly

    Institute of Scientific and Technical Information of China (English)

    LIANG; Shu-hong; ZHU; Qing-fu; ZHOU; Qi; QUAN; Yan-hui; YANG; Li-jun; LUO; Huang-da; LIU; Yang; ZHANG; Wei; ZHOU; Xiao-ping; LIU; Dong-hai

    2015-01-01

    During the twelfth Five-Year period,Reactor Physics Laboratory has taken on the research item about spent fuel dissolver critical experiment in nuclear power development project,which should be accomplished by using the uranium solution nuclear critical safety experiment device.Due to the differences of experimental content

  3. Physics Design of Criticality Assembly in Experimental Research About Criticality Safety in Spent Fuel Dissolver

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Qi

    2012-01-01

    <正>In order to meet the experimental demand of criticality safety research in the spent fuel dissolver, we need to design a suitable criticality assembly. The key problem of the design work is the core design because there are many limits for it such as the number of fuel rods loaded, fissile materials existed in the solution, reactivity control, core size and etc.

  4. Sequential Determination of Free Acidity and Plutonium Concentration in the Dissolver Solution of Fast-Breeder Reactor Spent Fuels in a Single Aliquot.

    Science.gov (United States)

    Dhamodharan, K; Pius, Anitha

    2016-01-01

    A simple potentiometric method for determining the free acidity without complexation in the presence of hydrolysable metal ions and sequentially determining the plutonium concentration by a direct spectrophotometric method using a single aliquot was developed. Interference from the major fission products, which are susceptible to hydrolysis at lower acidities, had been investigated in the free acidity measurement. This method is applicable for determining the free acidity over a wide range of nitric acid concentrations as well as the plutonium concentration in the irradiated fuel solution prior to solvent extraction. Since no complexing agent is introduced during the measurement of the free acidity, the purification step is eliminated during the plutonium estimation, and the resultant analytical waste is free from corrosive chemicals and any complexing agent. Hence, uranium and plutonium can be easily recovered from analytical waste by the conventional solvent extraction method. The error involved in determining the free acidity and plutonium is within ±1% and thus this method is superior to the complexation method for routine analysis of plant samples and is also amenable for remote analysis.

  5. Bubble Effect in Heterogeneous Nuclear Fuel Solution System

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Xiao-ping; LUO; Huang-da; ZHANG; Wei; ZHU; Qing-fu

    2013-01-01

    Bubble effect means system reactivity changes due to the bubble induced solution volume,neutron leakage and absorption properties,neutron energy spectrum change in the nuclear fuel solution system.In the spent fuel dissolver,during uranium element shearing,the oxygen will be inlet to accelerate the

  6. Dissolution of spent nuclear fuel in carbonate-peroxide solution

    Science.gov (United States)

    Soderquist, Chuck; Hanson, Brady

    2010-01-01

    This study shows that spent UO2 fuel can be completely dissolved in a room temperature carbonate-peroxide solution apparently without attacking the metallic Mo-Tc-Ru-Rh-Pd fission product phase. In parallel tests, identical samples of spent nuclear fuel were dissolved in nitric acid and in an ammonium carbonate, hydrogen peroxide solution. The resulting solutions were analyzed for strontium-90, technetium-99, cesium-137, europium-154, plutonium, and americium-241. The results were identical for all analytes except technetium, where the carbonate-peroxide dissolution had only about 25% of the technetium that the nitric acid dissolution had.

  7. Fuel cells problems and solutions

    CERN Document Server

    Bagotsky, Vladimir S

    2012-01-01

    The comprehensive, accessible introduction to fuel cells, their applications, and the challenges they pose Fuel cells-electrochemical energy devices that produce electricity and heat-present a significant opportunity for cleaner, easier, and more practical energy. However, the excitement over fuel cells within the research community has led to such rapid innovation and development that it can be difficult for those not intimately familiar with the science involved to figure out exactly how this new technology can be used. Fuel Cells: Problems and Solutions, Second Edition addresses this i

  8. Analysis of maximum allowable fragment heights during dissolution of high flux isotope reactor fuel in an h-canyon dissolver

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-17

    As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U3O8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H2. The HFIR fuel cores will be dissolved using a flowsheet developed by the Savannah River National Laboratory (SRNL) in either the 6.4D or 6.1D dissolver using a unique insert. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The recovered U will be down-blended into low-enriched U for subsequent use as commercial reactor fuel. During the development of the HFIR fuel dissolution flowsheet, the cycle time for the initial core was estimated at 28 to 40 h. Once the cycle is complete, H-Canyon personnel will open the dissolver and probe the HFIR insert wells to determine the height of any fuel fragments which did not dissolve. Before the next core can be charged to the dissolver, an analysis of the potential for H2 gas generation must show that the combined surface area of the fuel fragments and the subsequent core will not generate H2 concentrations in the dissolver offgas which exceeds 60% of the lower flammability limit (LFL) of H2 at 200 °C. The objective of this study is to identify the maximum fuel fragment height as a function of the Al concentration in the dissolving solution which will provide criteria for charging successive HFIR cores to an H-Canyon dissolver.

  9. Corrosion of irradiated MOX fuel in presence of dissolved H 2

    Science.gov (United States)

    Carbol, P.; Fors, P.; Van Winckel, S.; Spahiu, K.

    2009-07-01

    The corrosion behaviour of irradiated MOX fuel (47 GWd/tHM) has been studied in an autoclave experiment simulating repository conditions. Fuel fragments were corroded at room temperature in a 10 mM NaCl/2 mM NaHCO 3 solution in presence of dissolved H 2 for 2100 days. The results show that dissolved H 2 in concentration 1 mM and higher inhibits oxidation and dissolution of the fragments. Stable U and Pu concentrations were measured at 7 × 10 -10 and 5 × 10 -11 M, respectively. Caesium was only released during the first two years of the experiment. The results indicate that the UO 2 matrix of a spent MOX fuel is the main contributor to the measured dissolution, while the corrosion of the high burn-up Pu-rich islands appears negligible.

  10. Mechanism of gold dissolving in alkaline thiourea solution

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-yuan; WANG Yun-yan

    2007-01-01

    Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/mol. Rate determining step is the process of gold thiourea complex diffusing away from electrode surface to solution. The results of AC impedance and chronopotentiometry indicate that thiourea adsorbs on gold electrode surface before dissolving in solution. There does not exist proceeding chemical reactions. Formamidine disulfide, the decomposed product of thiourea, does not participate the process of gold dissolution and thiourea complex. Species with electro-activity produced in the process of electrode reaction adsorbs on the electrode surface. In alkaline thiourea solution, gold dissolving mechanism undergoes the following courses: adsorption of thiourea on electrode surface; charge transfer from gold atom to thiourea molecule; Au[SC(NH2)2]ads+ receiving a thiourea molecule and forming stable Au[SC(NH2)2]2+; and then Au[SC(NH2)2]2+diffusing away from the electrode surface to solution, the last step is the rate-determining one.

  11. Thermodynamic properties of gases dissolved in electrolyte solutions.

    Science.gov (United States)

    Tiepel, E. W.; Gubbins, K. E.

    1973-01-01

    A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

  12. Electrochemical kinetics of gold dissolving in alkaline thiourea solution

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-yuan; WANG Yun-yan

    2006-01-01

    Kinetic parameters of the electrode reactions were measured by investigating steady-state current-potential behaviors. The results show that the apparent transfer coefficient of anodic process is 0.058 2, diffusion coefficient of thiourea gold complex is 6.04 × 10-6 cm2/s,anodic reaction order of thiourea is 2. 018 3, and anodic reaction order of OH- is 0. 016 6. The theoretical kinetics equation of gold dissolving in alkaline thiourea solution is deduced,which indicates that anodic reaction order of thiourea is 2, and anodic reaction order of OH- is 0. The theoretical values of the kinetic parameters are consistent with experimental values very well. The correctness of the mechanism is further demonstrated using apparent transfer coefficient according to the electrochemical dynamic equation of multi-electron reaction.

  13. FLOWSHEET EVALUATION FOR THE DISSOLVING AND NEUTRALIZATION OF SODIUM REACTOR EXPERIMENT USED NUCLEAR FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E.; Hansen, E. K.; Shehee, T. C.

    2012-10-30

    This report includes the literature review, hydrogen off-gas calculations, and hydrogen generation tests to determine that H-Canyon can safely dissolve the Sodium Reactor Experiment (SRE; thorium fuel), Ford Nuclear Reactor (FNR; aluminum alloy fuel), and Denmark Reactor (DR-3; silicide fuel, aluminum alloy fuel, and aluminum oxide fuel) assemblies in the L-Bundles with respect to the hydrogen levels in the projected peak off-gas rates. This is provided that the number of L-Bundles charged to the dissolver is controlled. Examination of SRE dissolution for potential issues has aided in predicting the optimal batching scenario. The calculations detailed in this report demonstrate that the FNR, SRE, and DR-3 used nuclear fuel (UNF) are bounded by MURR UNF and may be charged using the controls outlined for MURR dissolution in a prior report.

  14. Impact of solute concentration on the electrocatalytic conversion of dissolved gases in buffered solutions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-04-24

    To maintain local pH levels near the electrode during electrochemical reactions, the use of buffer solutions is effective. Nevertheless, the critical effects of the buffer concentration on electrocatalytic performances have not been discussed in detail. In this study, two fundamental electrochemical reactions, oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR), on a platinum rotating disk electrode are chosen as model gas-related aqueous electrochemical reactions at various phosphate concentrations. Our detailed investigations revealed that the kinetic and limiting diffusion current densities for both the ORR and HOR logarithmically decrease with increasing solute concentration (log|jORR|=-0.39c+0.92,log|jHOR|=-0.35c+0.73). To clarify the physical aspects of this phenomenon, the electrolyte characteristics are addressed: with increasing phosphate concentration, the gas solubility decrease, the kinematic viscosity of the solution increase and the diffusion coefficient of the dissolved gases decrease. The simulated limiting diffusion currents using the aforementioned parameters match the measured ones very well (log|jORR|=-0.43c+0.99,log|jHOR|=-0.40c+0.54), accurately describing the consequences of the electrolyte concentration. These alterations of the electrolyte properties associated with the solute concentration are universally applicable to other aqueous gas-related electrochemical reactions because the currents are purely determined by mass transfer of the dissolved gases. © 2015 The Authors.

  15. Asymptotic Solutions of Serial Radial Fuel Shuffling

    Directory of Open Access Journals (Sweden)

    Xue-Nong Chen

    2015-12-01

    Full Text Available In this paper, the mechanism of traveling wave reactors (TWRs is investigated from the mathematical physics point of view, in which a stationary fission wave is formed by radial fuel drifting. A two dimensional cylindrically symmetric core is considered and the fuel is assumed to drift radially according to a continuous fuel shuffling scheme. A one-group diffusion equation with burn-up dependent macroscopic coefficients is set up. The burn-up dependent macroscopic coefficients were assumed to be known as functions of neutron fluence. By introducing the effective multiplication factor keff, a nonlinear eigenvalue problem is formulated. The 1-D stationary cylindrical coordinate problem can be solved successively by analytical and numerical integrations for associated eigenvalues keff. Two representative 1-D examples are shown for inward and outward fuel drifting motions, respectively. The inward fuel drifting has a higher keff than the outward one. The 2-D eigenvalue problem has to be solved by a more complicated method, namely a pseudo time stepping iteration scheme. Its 2-D asymptotic solutions are obtained together with certain eigenvalues keff for several fuel inward drifting speeds. Distributions of the neutron flux, the neutron fluence, the infinity multiplication factor kinf and the normalized power are presented for two different drifting speeds.

  16. A study on the expulsion of iodine from spent-fuel solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Tsutomu; Takahashi, Akira; Ishikawa, Niroh [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)] [and others

    1995-02-01

    During dissolution of spent nuclear fuels, some radioiodine remains in spent-fuel solutions. Its expulsion to dissolver off-gas is important to minimize iodine escape to the environment. In our current work, the iodine remaining in spent-fuel solutions varied from 0 to 10% after dissolution of spent PWR-fuel specimens (approximately 3 g each). The amount remaining probably was dependent upon the dissolution time required. The cause is ascribable to the increased nitrous acid concentration that results from NOx generated during dissolution. The presence of nitrous acid was confirmed spectrophotometrically in an NO-HNO{sub 3} system at 100{degrees}C. Experiments examining NOx concentration versus the quantity of iodine in a simulated spent-fuel solution indicate that iodine (I{minus}) in spent fuels is subjected to the following three reactions: (1) oxidation into I{sub 2} by nitric acid, (2) oxidation into I{sub 2} by nitrous acid arising from NOx, and (3) formation of colloidal iodine (AgI, PdI{sub 2}), the major iodine species in a spent-fuel solution. Reaction (2) competes with reaction (3) to control the quantity of iodine remaining in solution. The following two-step expulsion process to remove iodine from a spent-fuel solution was derived from these experiments: Step One - Heat spent-fuel solutions without NOx sparging. When aged colloidal iodine is present, an excess amount of iodate should be added to the solution. Step Two - Sparge the fuel solution with NOx while heating. Effect of this new method was confirmed by use of a spent PWR-fuel solution.

  17. Dissolution of Material and Test reactor Fuel in an H-Canyon Dissolver

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-26

    In an amended record of decision for the management of spent nuclear fuel (SNF) at the Savannah River Site, the US Department of Energy has authorized the dissolution and recovery of U from 1000 bundles of Al-clad SNF. The SNF is fuel from domestic and foreign research reactors and is typically referred to as Material Test Reactor (MTR) fuel. Bundles of MTR fuel containing assemblies fabricated from U-Al alloys (or other U compounds) are currently dissolved using a Hg-catalyzed HNO3 flowsheet. Since the development of the existing flowsheet, improved experimental methods have been developed to more accurately characterize the offgas composition and generation rate during laboratory dissolutions. Recently, these new techniques were successfully used to develop a flowsheet for the dissolution of High Flux Isotope Reactor (HFIR) fuel. Using the data from the HFIR dissolution flowsheet development and necessary laboratory experiments, the Savannah River National Laboratory (SRNL) was requested to define flowsheet conditions for the dissolution of MTR fuels. With improved offgas characterization techniques, SRNL will be able define the number of bundles of fuel which can be charged to an H-Canyon dissolver with much less conservatism.

  18. Corrosion investigations on zircaloy-4 and titanium dissolver materials for MOX fuel dissolution in concentrated nitric acid containing fluoride ions

    Science.gov (United States)

    Jayaraj, J.; Krishnaveni, P.; Krishna, D. Nanda Gopala; Mallika, C.; Mudali, U. Kamachi

    2016-05-01

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a dissolution catalyst in boiling nitric acid for an effective dissolution of the spent fuel. High corrosion rates were obtained for the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO3 + 0.05 M NaF. Complexing the fluoride ions either with Al(NO3)3 or ZrO(NO3)2 aided in decreasing the corrosion rates of Zr-4 and CP-Ti. From the obtained corrosion rates it is concluded that CP-Ti is a better dissolver material than Zr-4 for extended service life in boiling 11.5 M HNO3 + 0.05 M NaF, when complexed with 0.15 M ZrO(NO3)2. XPS analysis confirmed the presence of TiO2 and absence of fluoride on the surface of CP-Ti samples, indicating that effective complexation had occurred in solution leading to passivation of the metal and imparting high corrosion resistance.

  19. Wavelength Dispersive X-ray Fluorescence Analysis of Actinides in Dissolved Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, David [Parallax Research, Inc., Tallahassee, FL (United States)

    2015-10-15

    There is an urgent need for an instrument that can quickly measure the concentration of Plutonium and other Actinides mixed with Uranium in liquids containing dissolved spent fuel rods. Parallax Research, Inc. proposes to develop an x-ray spectrometer capable of measuring U, Np and Pu in dissolved nuclear fuel rod material to less than 10 ppm levels to aid in material process control for these nuclear materials. Due to system noise produced by high radioactivity, previous x-ray spectrometers were not capable of low level measurements but the system Parallax proposed has no direct path for undesired radiation to get to the detector and the detector in the proposed device is well shielded from scatter and has very low dark current. In addition, the proposed spectrometer could measure these three elements simultaneously, also measuring background positions with an energy resolution of roughly 100 eV making it possible to see a small amount of Pu that would be hidden under the tail of the U peak in energy dispersive spectrometers. Another nearly identical spectrometer could be used to target Am and Cm if necessary. The proposed spectrometer needs only a tiny sample of roughly 1 micro-liter (1 mm3) and the measurement can be done with the liquid flowing in a radiation and chemical immune quartz capillary protected by a stainless steel rod making it possible to continuously monitor the liquid or to use a capillary manifold to measure other liquid streams. Unlike other methods such as mass spectroscopy where the sample must be taken to a remote facility and might take days for turn-around, the proposed measurement should take less than an hour. This spectrometer could enable near real-time measurement of U, Pu and Np in dilute dissolved spent nuclear fuel rod streams.

  20. Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

    Science.gov (United States)

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

  1. Shelf life, dissolving action, and antibacterial activity of a neutralized 2.5% sodium hypochlorite solution.

    Science.gov (United States)

    Camps, Jean; Pommel, Ludovic; Aubut, Virginie; Verhille, Bernard; Satoshi, Fukuzaki; Lascola, Bernad; About, Imad

    2009-08-01

    The aim was to evaluate the shelf life and the dissolving and antibacterial properties of a neutralized 2.5% NaOCl solution. The loss of available chlorine and the pH of the neutralized 2.5% NaOCl solution were recorded to determine its shelf life. The dissolving action on bovine dental pulp was assessed measuring weight loss, pH variation, and decrease in available chlorine content. The antibacterial activity was evaluated on artificially infected human teeth. The roots were endodontically prepared, sterilized, and inoculated with Enterococcus faecalis before irrigation with the neutralized solution. The presence of intracanal bacteria after irrigation was recorded. The neutralized solution presented a shelf life of 2 hours, dissolving capacities equivalent to control for the first 5 minutes, and a better antibacterial efficiency. The neutralized 2.5% NaOCl solution must be used within 2 hours after mixing, should be frequently renewed to maintain its dissolving capacities, and presented enhanced antibacterial properties.

  2. The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

    Energy Technology Data Exchange (ETDEWEB)

    Carbol, P. [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K. (ed.) [and others

    2005-03-01

    In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

  3. Hydrogen Fuel Cells: Part of the Solution

    Science.gov (United States)

    Busby, Joe R.; Altork, Linh Nguyen

    2010-01-01

    With the decreasing availability of oil and the perpetual dependence on foreign-controlled resources, many people around the world are beginning to insist on alternative fuel sources. Hydrogen fuel cell technology is one answer to this demand. Although modern fuel cell technology has existed for over a century, the technology is only now becoming…

  4. Hydrogen Fuel Cells: Part of the Solution

    Science.gov (United States)

    Busby, Joe R.; Altork, Linh Nguyen

    2010-01-01

    With the decreasing availability of oil and the perpetual dependence on foreign-controlled resources, many people around the world are beginning to insist on alternative fuel sources. Hydrogen fuel cell technology is one answer to this demand. Although modern fuel cell technology has existed for over a century, the technology is only now becoming…

  5. Effect of dissolved organic matter composition on metal speciation in soil solutions

    NARCIS (Netherlands)

    Ren, Zong Ling; Tella, Marie; Bravin, M.N.; Comans, R.N.J.; Dai, Jun; Garnier, Jean Marie; Sivry, Yann; Doelsch, Emmanuel; Straathof, Angela; Benedetti, M.F.

    2015-01-01

    Knowledge of the speciation of heavy metals and the role of dissolved organic matter (DOM) in soil solution is a key to understand metal mobility and ecotoxicity. In this study, soil column-Donnan membrane technique (SC-DMT) was used to measure metal speciation of Cd, Cu, Ni, Pb, and Zn in eighte

  6. Corrosion investigations on zircaloy-4 and titanium dissolver materials for MOX fuel dissolution in concentrated nitric acid containing fluoride ions

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J.; Krishnaveni, P.; Krishna, D. Nanda Gopala; Mallika, C.; Mudali, U. Kamachi, E-mail: kamachi@igcar.gov.in

    2016-05-15

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a dissolution catalyst in boiling nitric acid for an effective dissolution of the spent fuel. High corrosion rates were obtained for the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO{sub 3} + 0.05 M NaF. Complexing the fluoride ions either with Al(NO{sub 3}){sub 3} or ZrO(NO{sub 3}){sub 2} aided in decreasing the corrosion rates of Zr-4 and CP-Ti. From the obtained corrosion rates it is concluded that CP-Ti is a better dissolver material than Zr-4 for extended service life in boiling 11.5 M HNO{sub 3} + 0.05 M NaF, when complexed with 0.15 M ZrO(NO{sub 3}){sub 2}. XPS analysis confirmed the presence of TiO{sub 2} and absence of fluoride on the surface of CP-Ti samples, indicating that effective complexation had occurred in solution leading to passivation of the metal and imparting high corrosion resistance. - Highlights: • Zr-4 and CP-Ti exhibited high corrosion rate in boiling fluorinated nitric acid. • Corrosion rate decreased in fluorinated nitric acid containing ZrO(NO{sub 3}){sub 2} and Al(NO{sub 3}){sub 3}. • High inhibiting efficiency is exhibited by 0.15 M ZrO(NO{sub 3}){sub 2} when compared to Al(NO{sub 3}){sub 3}. • Corrosion rates of CP-Ti were negligible in complexed fluorinated nitric acid. • XPS analysis on CP-Ti confirmed the presence of TiO{sub 2} and absence of fluoride.

  7. Research on the influence of ozone dissolved in the fuel-water emulsion on the parameters of the CI engine

    Science.gov (United States)

    Wojs, M. K.; Orliński, P.; Kamela, W.; Kruczyński, P.

    2016-09-01

    The article presents the results of empirical research on the impact of ozone dissolved in fuel-water emulsion on combustion process and concentration of toxic substances in CI engine. The effect of ozone presence in the emulsion and its influence on main engine characteristics (power, torque, fuel consumption) and selected parameters that characterize combustion process (levels of pressures and temperatures in combustion chamber, period of combustion delay, heat release rate, fuel burnt rate) is shown. The change in concentration of toxic components in exhausts gases when engine is fueled with ozonized emulsion was also identified. The empirical research and their analysis showed significant differences in the combustion process when fuel-water emulsion containing ozone was used. These differences include: increased power and efficiency of the engine that are accompanied by reduction in time of combustion delay and beneficial effects of ozone on HC, PM, CO and NOX emissions.

  8. Effects of Dissolving Solutions on the Accuracy of an Electronic Apex Locator-Integrated Endodontic Handpiece

    Science.gov (United States)

    Ustun, Yakup; Uzun, Ozgur; Er, Ozgur; Maden, Murat; Yalpı, Fatma; Canakci, Burhan Can

    2013-01-01

    The effects of three dissolving agents on the accuracy of an electronic apex locator- (EAL-) integrated endodontic handpiece during retreatment procedures were evaluated. The true lengths (TLs) of 56 extracted incisor teeth were determined visually. Twenty teeth were filled with gutta-percha and a resin-based sealer (group A), 20 with gutta-percha and a zinc oxide/eugenol-based sealer (group B), and 16 roots were used as the control group (group C). All roots were prepared to TL. Guttasolv, Resosolv, and Endosolv E were used as the dissolving solutions. Two evaluations of the handpiece were performed: the apical accuracy during the auto reverse function (ARL) and the apex locator function (EL) alone. The ARL function of the handpiece gave acceptable results. There were significant differences between the EL mode measurements and the TL (P < 0.05). In these comparisons, Tri Auto ZX EL mode measurements were significantly shorter than those of the TL. PMID:24379743

  9. Measurement of CO(2) Dissolved in Aqueous Solutions Using a Modified Infrared Gas Analyzer System.

    Science.gov (United States)

    Schumacher, T E; Smucker, A J

    1983-05-01

    Total dissolved inorganic carbon (SigmaCO(2)) and aqueous carbon dioxide (H(2)CO(3) (*)) in nutrient solutions may be measured by the injection of small gas or liquid samples (1 microliter to 8 milliliters) into a gas stripping column connected in-line with an infrared gas analyzer. The measurement of SigmaCO(2) in solution requires sample acidification, while H(2)CO(3) (*) and gaseous CO(2) are measured without the addition of lactic acid. The standard curve for SigmaCO(2) was linear up to 300 nanomoles CO(2). Maximum sensitivity was approximately 300 picomoles. Measurements of H(2)CO(3) (*) were independent of pH. Consequently, SigmaCO(2) and H(2)CO(3) (*) could be used to calculate the pH, HCO(3) (-), and CO(3) (2-) values of nutrient solutions. Injection and complete analyses required from 0.8 to 2 minutes.

  10. The dissolution rate of unirratiated uranium dioxide under repository conditions: The influence of fuel and water chemistry, dissolved oxygen, and temperature

    Science.gov (United States)

    Casella, Amanda J.

    The dissolution rate of both unirradiated UO2 and spent fuel has been studied by numerous countries as part of the performance assessments of proposed geologic repositories. The effects of variables such as temperature, dissolved oxygen, and water and fuel chemistry on the dissolution rates of the fuel are necessary to provide a quantitative estimate of the potential dose over geologic time frames. The primary objective of this research was to determine the influence these parameters have on the dissolution rate of unirradiated UO2 under Yucca Mountain repository conditions and compare them to the current Yucca Mountain Model. Fuels containing between 0 and 8 wt% Gd2O3-doped UO2 were tested in a single-pass flow-through setup. These tests have verified that in bicarbonate solutions as temperature increased the dissolution rate increased. However, the presence of silicate in the feedwater altered the system and lowered the dissolution rate at higher temperatures. Pure UO 2 samples exhibited a dependence on the dissolved oxygen concentration, which in the current experiments was varied from 3.0 to 8.7 ppm. The significance of this dissolved oxygen dependence increased with rising temperature. At 75ºC the powder samples had a maximum dependence of 0.7, although the fragment samples had a much larger dependence up to 2.2. For the case of the Gd2O3-doped samples, there was minimal oxygen dependence at any temperature. The Gd2O3-dopant stabilized the fuel matrix, which lowered the dissolution rates by over an order of magnitude at the higher dopant levels. This effect in lowering the dissolution rate was more pronounced at higher temperatures, and additional dopant continued to decrease the dissolution rate up to the 4 wt% Gd2O3-doped UO2 tested. The dissolution rates for pure UO2 compared reasonably well with the Yucca Mountain Model for tests performed at 50ºC and 75ºC, but were found to be approximately half the values predicted by the model at 25ºC. After long

  11. Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene

    National Research Council Canada - National Science Library

    Tsai, Hung-Sheng; Tsai, Teh-Hua

    2012-01-01

    The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied...

  12. Methods of deoxygenating metals having oxygen dissolved therein in a solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying; Fang, Zhigang Zak; Sun, Pei; Xia, Yang; Zhou, Chengshang

    2017-06-06

    A method of deoxygenating metal can include forming a mixture of: a metal having oxygen dissolved therein in a solid solution, at least one of metallic magnesium and magnesium hydride, and a magnesium-containing salt. The mixture can be heated at a deoxygenation temperature for a period of time under a hydrogen-containing atmosphere to form a deoxygenated metal. The deoxygenated metal can then be cooled. The deoxygenated metal can optionally be subjected to leaching to remove by-products, followed by washing and drying to produce a final deoxygenated metal.

  13. Influences of dissolved oxygen concentration on biocathodic microbial communities in microbial fuel cells.

    Science.gov (United States)

    Rago, Laura; Cristiani, Pierangela; Villa, Federica; Zecchin, Sarah; Colombo, Alessandra; Cavalca, Lucia; Schievano, Andrea

    2017-08-01

    Dissolved oxygen (DO) at cathodic interface is a critical factor influencing microbial fuel cells (MFC) performance. In this work, three MFCs were operated with cathode under different DO conditions: i) air-breathing (A-MFC); ii) water-submerged (W-MFC) and iii) assisted by photosynthetic microorganisms (P-MFC). A plateau of maximum current was reached at 1.06±0.03mA, 1.48±0.06mA and 1.66±0.04mA, increasing respectively for W-MFC, P-MFC and A-MFC. Electrochemical and microbiological tools (Illumina sequencing, confocal microscopy and biofilm cryosectioning) were used to explore anodic and cathodic biofilm in each MFC type. In all cases, biocathodes improved oxygen reduction reaction (ORR) as compared to abiotic condition and A-MFC was the best performing system. Photosynthetic cultures in the cathodic chamber supplied high DO level, up to 16mgO2L(-1), which sustained aerobic microbial community in P-MFC biocathode. Halomonas, Pseudomonas and other microaerophilic genera reached >50% of the total OTUs. The presence of sulfur reducing bacteria (Desulfuromonas) and purple non-sulfur bacteria in A-MFC biocathode suggested that the recirculation of sulfur compounds could shuttle electrons to sustain the reduction of oxygen as final electron acceptor. The low DO concentration limited the cathode in W-MFC. A model of two different possible microbial mechanisms is proposed which can drive predominantly cathodic ORR. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Dissolving cellulose with twin-screw extruder in a NaOH complex aqueous solution

    Science.gov (United States)

    Yang, Y. P.; Zhang, Y.; Dawelbeit, A.; Yu, M. H.

    2016-07-01

    Novel cellulose dissolution method with twin-screw extruder was developed in order to improve the dissolution property, to simplify production procedure and to produce cellulose spinning dope which is stable and which has a higher concentration of cellulose. Therefore, the extrusion conditions on the cellulose dissolution in NaOH/thiourea/urea were extensively studied in this work. The resulted extrudates of twin-screw extruder dissolution method were characterized by polarized optical microscope image, the solubility experiment and the apparent viscosity. The results revealed that the screw revolution speed of such process could improve the solubility value (S a) of cellulose, and the solubility of cellulose reached a maximum value of 7.5 wt% at higher revolutions 450 rpm. On the other hand, the cellulose solutions were more transparent and balanced with its apparent viscosity values lower and more stable compare to stirring method, which indicated dissolving cellulose with twin-screw extruder was reliable. Moreover, the whole dissolving time is quite short, and the process is simple. The soluble effect of twin screw extrusion was far superior to traditional stirring, and the most suitable temperature was -2°C.

  15. Supply Chain-based Solution to Prevent Fuel Tax Evasion

    Energy Technology Data Exchange (ETDEWEB)

    Franzese, Oscar [ORNL; Capps, Gary J [ORNL; Daugherty, Michael [United States Department of Transportation (USDOT), Federal Highway Administration (FHWA); Siekmann, Adam [ORNL; Lascurain, Mary Beth [ORNL; Barker, Alan M [ORNL

    2016-01-01

    The primary source of funding for the United States transportation system is derived from motor fuel and other highway use taxes. Loss of revenue attributed to fuel-tax evasion has been assessed to be somewhere between $1 billion per year, or approximately 25% of the total tax collected. Any solution that addresses this problem needs to include not only the tax-collection agencies and auditors, but also the carriers transporting oil products and the carriers customers. This paper presents a system developed by the Oak Ridge National Laboratory for the Federal Highway Administration which has the potential to reduce or eliminate many fuel-tax evasion schemes. The solution balances the needs of tax-auditors and those of the fuel-hauling companies and their customers. The technology was deployed and successfully tested during an eight-month period on a real-world fuel-hauling fleet. Day-to-day operations of the fleet were minimally affected by their interaction with this system. The results of that test are discussed in this paper.

  16. Radiation Re-solution Calculation in Uranium-Silicide Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Unal, Cetin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-27

    The release of fission gas from nuclear fuels is of primary concern for safe operation of nuclear power plants. Although the production of fission gas atoms can be easily calculated from the fission rate in the fuel and the average yield of fission gas, the actual diffusion, behavior, and ultimate escape of fission gas from nuclear fuel depends on many other variables. As fission gas diffuses through the fuel grain, it tends to collect into intra-granular bubbles, as portrayed in Figure 1.1. These bubbles continue to grow due to absorption of single gas atoms. Simultaneously, passing fission fragments can cause collisions in the bubble that result in gas atoms being knocked back into the grain. This so called “re-solution” event results in a transient equilibrium of single gas atoms within the grain. As single gas atoms progress through the grain, they will eventually collect along grain boundaries, creating inter-granular bubbles. As the inter-granular bubbles grow over time, they will interconnect with other grain-face bubbles until a pathway is created to the outside of the fuel surface, at which point the highly pressurized inter-granular bubbles will expel their contents into the fuel plenum. This last process is the primary cause of fission gas release. From the simple description above, it is clear there are several parameters that ultimately affect fission gas release, including the diffusivity of single gas atoms, the absorption and knockout rate of single gas atoms in intra-granular bubbles, and the growth and interlinkage of intergranular bubbles. Of these, the knockout, or re-solution rate has an particularly important role in determining the transient concentration of single gas atoms in the grain. The re-solution rate will be explored in the following sections with regards to uranium-silicide fuels in order to support future models of fission gas bubble behavior.

  17. Effects of Chromophoric Dissolved Organic Matter on Anthracene Photolysis Kinetics in Aqueous Solution and Ice.

    Science.gov (United States)

    Malley, Philip P A; Grossman, Jarod N; Kahan, Tara F

    2017-09-27

    We measured photolysis kinetics of the PAH anthracene in aqueous solution, in bulk ice, and at ice surfaces in the presence and absence of chromophoric dissolved organic matter (CDOM). Self-association, which occurs readily at ice surfaces, may be responsible for the faster anthracene photolysis observed there. Photolysis rate constants in liquid water increased under conditions where anthracene self-association was observed. Concomitantly, kinetics changed from first-order to second-order, indicating that the photolysis mechanism at ice surfaces might be different than that in aqueous solution. Other factors that could lead to faster photolysis at ice surfaces were also investigated. Increased photon fluxes due to scattering in the ice samples can account for at most 20% of the observed rate increase, and other factors including singlet oxygen ((1)O2*) production and changes in pH and polarity were determined not to be responsible for the faster photolysis. CDOM (in the form of fulvic acid (FA)) did not affect anthracene photolysis kinetics in aqueous solution but suppressed photolysis in ice cubes and ice granules (by 30% and 56%, respectively). This was primarily due to competitive photon absorption (the inner filter effect). Freeze-concentration (or "salting out") appears to slightly increase the suppressing effects of FA on anthracene photolysis. This may be due to increased competitive photon absorption or to physical interactions between anthracene and FA.

  18. Trends in soil solution dissolved organic carbon (DOC) concentrations across European forests

    Science.gov (United States)

    Camino-Serrano, Marta; Graf Pannatier, Elisabeth; Vicca, Sara; Luyssaert, Sebastiaan; Jonard, Mathieu; Ciais, Philippe; Guenet, Bertrand; Gielen, Bert; Peñuelas, Josep; Sardans, Jordi; Waldner, Peter; Etzold, Sophia; Cecchini, Guia; Clarke, Nicholas; Galić, Zoran; Gandois, Laure; Hansen, Karin; Johnson, Jim; Klinck, Uwe; Lachmanová, Zora; Lindroos, Antti-Jussi; Meesenburg, Henning; Nieminen, Tiina M.; Sanders, Tanja G. M.; Sawicka, Kasia; Seidling, Walter; Thimonier, Anne; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Janssens, Ivan A.

    2016-10-01

    Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas increasing concentrations in European surface waters over the past decades appear to be the norm, possibly as a result of recovery from acidification. The objectives of this study were therefore to understand the long-term trends of soil solution DOC from a large number of European forests (ICP Forests Level II plots) and determine their main physico-chemical and biological controls. We applied trend analysis at two levels: (1) to the entire European dataset and (2) to the individual time series and related trends with plot characteristics, i.e., soil and vegetation properties, soil solution chemistry and atmospheric deposition loads. Analyses of the entire dataset showed an overall increasing trend in DOC concentrations in the organic layers, but, at individual plots and depths, there was no clear overall trend in soil solution DOC. The rate change in soil solution DOC ranged between -16.8 and +23 % yr-1 (median = +0.4 % yr-1) across Europe. The non-significant trends (40 %) outnumbered the increasing (35 %) and decreasing trends (25 %) across the 97 ICP Forests Level II sites. By means of multivariate statistics, we found increasing trends in DOC concentrations with increasing mean nitrate (NO3-) deposition and increasing trends in DOC concentrations with decreasing mean sulfate (SO42-) deposition, with the magnitude of these relationships depending on plot deposition history. While the attribution of increasing trends in DOC to the reduction of SO42- deposition could be confirmed in low to medium N deposition areas, in agreement with observations in surface waters, this was not the case in high N deposition areas. In

  19. Oxidative dissolution of spent nuclear fuel in aqueous alkaline solutions - An alternative to the Purex process?

    Energy Technology Data Exchange (ETDEWEB)

    Runde, Wolfgang; Peper, Shane; Brodnax, Lia; Crooks, William; Zehnder, Ralph; Jarvinen, Gordon

    2004-07-01

    As an alternative to acidic reprocessing of spent nuclear, oxidative dissolution of UO{sub 2} into aqueous alkaline solutions and subsequent separation of fission products is considered. The efficacy of such a method is limited by the kinetics of the UO{sub 2} dissolution and the capacity of alkaline solutions for dissolved U(VI) species. We performed a series of dissolution studies on UO{sub 2} and U{sub 3}O{sub 8} in aqueous alkaline solutions applying various oxidants. Among the oxidative agents commonly used to transform low-valence actinides into their higher oxidation states, H{sub 2}O{sub 2} has proven to be the most effective in basic media. Consequently, we investigated the dissolution of UO{sub 2} and U{sub 3}O{sub 8} in NaOH-H{sub 2}O{sub 2} and Na{sub 2}CO{sub 3}-H{sub 2}O{sub 2} solutions and determined the dissolution kinetics as a function of peroxide and hydroxide (carbonate) concentrations. Methods to remove fission products, e.g., Cs, Sr, Ba and Zr, from alkaline solutions will be evaluated based upon their decontamination factors. We will discuss the feasibility of using chemically oxidizing alkaline solutions as an alternative spent nuclear fuel reprocessing method based on results from experimental quantitative investigations. (authors)

  20. Adsorption and desorption of dissolved organic matter by carbon nanotubes: Effects of solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-06-01

    Increasing use of carbon nanotubes (CNTs) has led to their introduction into the environment where they can interact with dissolved organic matter (DOM). This study focuses on solution chemistry effects on DOM adsorption/desorption processes by single-walled CNTs (SWCNTs). Our data show that DOM adsorption is controlled by the attachment of DOM molecules to the SWCNTs, and that the initial adsorption rate is dependent on solution parameters. Adsorbed amount of DOM at high ionic strength was limited, possibly due to alterations in SWCNT bundling. Desorption of DOM performed at low pH resulted in additional DOM adsorption, whereas at high pH, adsorbed DOM amount decreased. The extent of desorption conducted at increased ionic strength was dependent on pre-adsorbed DOM concentration: low DOM loading stimulated additional adsorption of DOM, whereas high DOM loading facilitated release of adsorbed DOM. Elevated ionic strength and increased adsorbed amount of DOM reduced the oxidation temperature of the SWCNTs, suggesting that changes in the assembly of the SWCNTs had occurred. Moreover, DOM-coated SWCNTs at increased ionic strength provided fewer sites for atrazine adsorption. This study enhances our understanding of DOM-SWCNT interactions in aqueous systems influenced by rapid changes in salinity, and facilitates potential use of SWCNTs in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Ecological consequences of elevated total dissolved solids associated with fossil fuel extraction in the United States

    Science.gov (United States)

    Fossil fuel burning is considered a major contributor to global climate change. The outlook for production and consumption of fossil fuels int he US indicates continued growth to support growing energy demands. For example, coal-generated electricity is projected ot increase from...

  2. A study on the microstructure of a nitrate ester plasticized polyether propellant dissolved in HCl and KOH solutions

    Directory of Open Access Journals (Sweden)

    YONG LIU

    2010-07-01

    Full Text Available Understanding of how the properties and performance of nitrate ester plasticized polyether (NEPE propellants relate to microstructure is complicated by numerous components that have different characteristics. One approach to alleviating these complications is to observe a microstructure that has lost one or several components. This article examines the dissolution process, mass loss and change of the ion concentration of propellants in acid and alkali solutions. A scanning electron microscope was used to observe the dissolved residual of the propellants. The results revealed that the main constituents of NEPE propellant have different dissolving properties in solutions of HCl and KOH. By monitoring the dissolution process of NEPE propellant in HCl and KOH solutions, it was found that the microstructure of the propellant is generally compact and the polymer binder not only binds all the other components, but also protects the inner part of the propellant in solution.

  3. Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM).

    Science.gov (United States)

    Clark, Catherine D; de Bruyn, Warren; Jones, Joshua G

    2014-02-15

    To explore whether quinone moieties are important in chromophoric dissolved organic matter (CDOM) photochemistry in natural waters, hydrogen peroxide (H2O2) production and associated optical property changes were measured in aqueous solutions irradiated with a Xenon lamp for CDOM model compounds (dihydroquinone, benzoquinone, anthraquinone, napthoquinone, ubiquinone, humic acid HA, fulvic acid FA). All compounds produced H2O2 with concentrations ranging from 15 to 500 μM. Production rates were higher for HA vs. FA (1.32 vs. 0.176 mM h(-1)); values ranged from 6.99 to 0.137 mM h(-1) for quinones. Apparent quantum yields (Θ app; measure of photochemical production efficiency) were higher for HA vs. FA (0.113 vs. 0.016) and ranged from 0.0018 to 0.083 for quinones. Dihydroquinone, the reduced form of benzoquinone, had a higher production rate and efficiency than its oxidized form. Post-irradiation, quinone compounds had absorption spectra similar to HA and FA and 3D-excitation-emission matrix fluorescence spectra (EEMs) with fluorescent peaks in regions associated with CDOM.

  4. Massachusetts Fuel Cell Bus Project: Demonstrating a Total Transit Solution for Fuel Cell Electric Buses in Boston

    Energy Technology Data Exchange (ETDEWEB)

    2017-05-22

    The Federal Transit Administration's National Fuel Cell Bus Program focuses on developing commercially viable fuel cell bus technologies. Nuvera is leading the Massachusetts Fuel Cell Bus project to demonstrate a complete transit solution for fuel cell electric buses that includes one bus and an on-site hydrogen generation station for the Massachusetts Bay Transportation Authority (MBTA). A team consisting of ElDorado National, BAE Systems, and Ballard Power Systems built the fuel cell electric bus, and Nuvera is providing its PowerTap on-site hydrogen generator to provide fuel for the bus.

  5. The role of fossil fuel combustion on the stability of dissolved iron in rainwater

    Science.gov (United States)

    Willey, Joan D.; Kieber, Robert J.; Humphreys, Joshua J.; Rice, Briana C.; Hopwood, Mark J.; Avery, G. Brooks; Mead, Ralph N.

    2015-04-01

    The concentration of dissolved Fe(II) has decreased in coastal NC rainwater because of less complexation and stabilization of Fe(II) (aq) by automobile and coal combustion emissions. Better emission control has removed stabilizing organic ligands hence dissolved Fe(II) currently occurs more as inorganic iron, which is not protected against oxidation. Increasing rainwater pH allows oxidation by molecular O2 in addition to H2O2 and also increases the ratio of the ion pair Fe(OH)+ to Fe(II) free ion, which increases the oxidation rates by both H2O2 and molecular oxygen. The concentration of H2O2 in rain has increased; hydrogen peroxide is the primary oxidant of inorganic Fe(II) in precipitation. The East Coast of the USA is also receiving less rain of terrestrial origin, which tends to be higher in dissolved iron and organic compounds. All these factors operate in the same direction and contribute to the lower concentrations and lack of stability of Fe(II) in rainwater currently observed. Results of this study suggest that wet deposition of soluble Fe(II) is an episodic, temporally variable factor in the iron cycle in oceanic regions adjacent to developed or developing coastal regions.

  6. Direct disposal of spent fuel: developing solutions tailored to Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Hideki [Obayashi Corporation, Tokyo (Japan); McKinley, Ian G [McKinley Consulting, Baden (Switzerland)

    2013-07-01

    With the past Government policy of 100% reprocessing in Japan now open to discussion, options for direct disposal of spent fuel (SF) are now being considered in Japan. The need to move rapidly ahead in developing spent fuel management concepts is closely related to the ongoing debate on the future of nuclear power in Japan and the desire to understand the true costs of the entire life cycle of different options. Different scenarios for future nuclear power - and associated decisions on extent of reprocessing - will give rise to quite different inventories of SF with different disposal challenges. Although much work has been carried out spent fuel disposal within other national programmes, the potential for mining the international knowledge base is limited by the boundary conditions for disposal in Japan. Indeed, with a volunteer approach to siting, no major salt deposits and few undisturbed sediments, high tectonic activity, relatively corrosive groundwater and no deserts, it is evident that a tailored solution is needed. Nevertheless, valuable lessons can be learned from projects carried out worldwide, if focus is placed on basic principles rather than implementation details. (authors)

  7. Urothelial injury to the rabbit bladder from various alkaline and acidic solutions used to dissolve kidney stones.

    Science.gov (United States)

    Reckler, J; Rodman, J S; Jacobs, D; Rotterdam, H; Marion, D; Vaughan, E D

    1986-07-01

    Different irrigating solutions are used clinically to dissolve uric acid, cystine and struvite stones. These studies were undertaken to assess the toxicity to the rabbit bladder epithelium of several commonly used formulations. Test solutions were infused antegrade through a left ureterotomy overnight. Bladders were removed and routine histological sections made. A pH 7.6 solution of NaHCO3 appeared harmless. The same solution with two per cent acetylcysteine produced slight injury. All pH 4 solutions caused significant damage to the urothelium. Hemiacidrin, which contains magnesium, produced less damage than did other pH 4 solutions without that cation. Our data tend to support Suby's conclusions that addition of magnesium reduces urothelial injury even though the presence of magnesium will slow dissolution of struvite.

  8. Dissolved and particulate Barium in the Ganga (Hooghly) River estuary, India: Solute-particle interactions and the enhanced dissolved flux to the oceans

    Science.gov (United States)

    Samanta, Saumik; Dalai, Tarun K.

    2016-12-01

    In this study, the sources and the cycling of Ba have been evaluated in the Ganga (Hooghly) River estuary using the composition of the suspended sediments and the water samples collected during six seasons of contrasting water discharge over two years (2012 and 2013). In addition, the data on the samples of groundwater from areas adjacent to the estuary, and the industrial effluent water and urban wastewater draining into the estuary are presented. Selective extraction experiments were also performed on the suspended particulate matter of two seasons to assess the distribution of exchangeable concentrations of major ions and Ba. In the mixing zone, the variation patterns of the dissolved Ba concentrations show mid-salinity maxima and are similar to the patterns of variation of the particulate Mg/Al and Mg/Fe, suggesting that the production of dissolved Ba is linked to the adsorption of major ions on to the clay minerals and Fe-Mn oxyhydroxides in the particulate matter. The inference of coupled adsorption-desorption processes is supported by the observations that the particulate Ba/Mg and Ba/K ratios exhibit significant to strong negative correlations with the concentrations of Al, Fe and Mn. The observations of mid-salinity maxima for the concentrations of exchangeable Mg and K, and of the exchangeable Ba concentrations that decrease with salinity provide strong evidence that the solute-particle interactions is the major driver in regulating the dissolved Ba distributions in the estuary. The estimates of the quantity of desorbed Ba based on three different approaches suggest that desorption is sufficient to account for the calculated excess Ba (Baxs) concentrations. The contribution of Ba to the dissolved load via dissolution of the particulate carbonate phases is minor, up to 3% of the maximum Baxs concentrations. The estimates of anthropogenic contributions are insignificant, and account for ⩽2% of maximum Baxs in the estuary. Groundwater contributions are

  9. Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene.

    Science.gov (United States)

    Tsai, Hung-Sheng; Tsai, Teh-Hua

    2012-01-04

    The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR₃ in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.

  10. Solar fuels via artificial photosynthesis: From homogeneous photocatalysis in solution to a photoelectrochemical cell

    NARCIS (Netherlands)

    Chen, H.-C.

    2016-01-01

    The conversion and storage of solar energy into fuels provides a valuable solution for the future energy demand of our society. Making fuels via artificial photosynthesis, the so-called solar-to-fuel approach, is viewed as one of the most promising ways to produce clean and renewable energy.

  11. Solar fuels via artificial photosynthesis: From homogeneous photocatalysis in solution to a photoelectrochemical cell

    NARCIS (Netherlands)

    H.-C. Chen

    2016-01-01

    The conversion and storage of solar energy into fuels provides a valuable solution for the future energy demand of our society. Making fuels via artificial photosynthesis, the so-called solar-to-fuel approach, is viewed as one of the most promising ways to produce clean and renewable energy. Solar-d

  12. Development of a CMPO based extraction process for partitioning of minor actinides and demonstration with genuine fast reactor fuel solution (155 GWd/Te)

    Energy Technology Data Exchange (ETDEWEB)

    Antony, M.P.; Kumaresan, R.; Suneesh, A.S. [Indira Gandhi Centre for Atomic Research, Kalpakkam (IN). Fuel Chemistry Div.] (and others)

    2011-07-01

    A method has been developed for partitioning of minor actinides from fast reactor (FR) fuel solution by a TRUEX solvent composed of 0.2 M n-octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO)-1.2 M tri-n-butylphosphate (TBP) in n-dodecane (n-DD), and subsequently demonstrated with genuine fast reactor dissolver solution (155 GWd/Te) using a novel 16-stage ejector mixer settler in hot cells. Cesium, plutonium and uranium present in the dissolver solution were removed, prior to minor actinide partitioning, by using ammonium molybdophosphate impregnated XAD-7 (AMP-XAD), methylated poly(4-vinylpyridine) (PVP-Me), and macroporous bifunctional phosphinic acid (MPBPA) resins respectively. Extraction of europium(III) and cerium(III) from simulated and real dissolver solution, and their stripping behavior from loaded organic phase was studied in batch method using various citric acid-nitric acid formulations. Based on these results, partitioning of minor actinides from fast reactor dissolver solution was demonstrated in hot cells. The extraction and stripping profiles of {sup 154}Eu, {sup 144}Ce, {sup 106}Ru and {sup 137}Cs, and mass balance of {sup 241}Am(III) achieved in the demonstration run have been reported in this paper. (orig.)

  13. Reprocessing method for spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hoshikawa, Tadahiro; Sawa, Toshio; Suzuoki, Akira [Hitachi Ltd., Tokyo (Japan); Takashima, Yoichi; Kumagai, Mikiro

    1998-09-29

    The present invention provides a method of reprocessing spent fuels to form MOX having a Pu/U ratio suitable to fuels of LWR or fast reactors and uranium oxides of fuels of an LWR reactor. In a brief separation step for uranium, carbonate is added to a nitric acid solution in which spent fuels are dissolved, to dissolve a portion of uranium in the nitric acid solution. The residual uranium, plutonium and fission products are made into complexes of carboxylic acid ions and precipitated. The precipitated complexes of carboxylic acid ions are brought into contact with a different nitric acid solution to recover the uranium, plutonium and fission products. The concentration of the carbonate in the nitric acid solution in which uranium is partially dissolved is determined in accordance with the plutonium/uranium ratio based on the relation between the saturation concentration of uranium to the concentration of carbonate in the nitric acid solution. (T.M.)

  14. Reclamation of cadmium-contaminated soil using dissolved organic matter solution originating from wine-processing waste sludge

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cheng-Chung, E-mail: ccliu@niu.edu.tw [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China); Chen, Guan-Bu [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China)

    2013-01-15

    Highlights: ► Increases in acidity, washing frequency, and operational temperature enhance the Cd removal. ► Approximately 80% of Cd can be removed from the soil by dissolved organic matter (DOM) washing. ► The DOM washing can moderate the loss of soil fertility. ► The DOM washing will have a great improvement if we employ NaOH, KOH, Ca(OH){sub 2}, and Mg(OH){sub 2} to prepare the DOM solution together. -- Abstract: Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, serious loss of nutrients from soil is a major drawback of the washing. Distillery sludge can be used to prepare a dissolved organic matter (DOM) solution by extracting its organic constituents with alkaline solutions. This study employed DOM solutions to remediate Cd-contaminated soil (with concentrations up to 21.5 mg kg{sup −1}) and determine the factors affecting removal of Cd, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with pH 3.0 and 1250 mg L{sup −1} DOM solution, about 80% and 81% of Cd were removed from the topsoil at 27 °C and subsoil at 40 °C, respectively. To summarize the changes in fertility during DOM washing with various pH solutions: the increase in organic matter content ranged from 7.7% to 23.7%; cation exchange capacity (CEC) ranged from 4.6% to 13.9%; available ammonium (N-NH{sub 4}) content ranged from 39.4% to 2175%; and available phosphorus content ranged from 34.5% to 182%. Exchangeable K, Ca, and Mg remained in the topsoil after DOM washing, with concentrations of 1.1, 2.4, and 1.5 times higher than those treated with HCl solution at the same pH, respectively.

  15. Influence of dissolved organic matter and manganese oxides on metal speciation in soil solution: A modelling approach.

    Science.gov (United States)

    Schneider, Arnaud R; Ponthieu, Marie; Cancès, Benjamin; Conreux, Alexandra; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice; Benedetti, Marc F

    2016-06-01

    Trace element (TE) speciation modelling in soil solution is controlled by the assumptions made about the soil solution composition. To evaluate this influence, different assumptions using Visual MINTEQ were tested and compared to measurements of free TE concentrations. The soil column Donnan membrane technique (SC-DMT) was used to estimate the free TE (Cd, Cu, Ni, Pb and Zn) concentrations in six acidic soil solutions. A batch technique using DAX-8 resin was used to fractionate the dissolved organic matter (DOM) into four fractions: humic acids (HA), fulvic acids (FA), hydrophilic acids (Hy) and hydrophobic neutral organic matter (HON). To model TE speciation, particular attention was focused on the hydrous manganese oxides (HMO) and the Hy fraction, ligands not considered in most of the TE speciation modelling studies in soil solution. In this work, the model predictions of free ion activities agree with the experimental results. The knowledge of the FA fraction seems to be very useful, especially in the case of high DOM content, for more accurately representing experimental data. Finally, the role of the manganese oxides and of the Hy fraction on TE speciation was identified and, depending on the physicochemical conditions of the soil solution, should be considered in future studies.

  16. Effect of TCE concentration and dissolved groundwater solutes on NZVI-promoted TCE dechlorination and H2 evolution.

    Science.gov (United States)

    Liu, Yueqiang; Phenrat, Tanapon; Lowry, Gregory V

    2007-11-15

    Nanoscale zero-valent iron (NZVI) is used to remediate contaminated groundwater plumes and contaminant source zones. The target contaminant concentration and groundwater solutes (NO3-, Cl-, HCO3-, SO4(2-), and HPO4(2-)) should affect the NZVI longevity and reactivity with target contaminants, but these effects are not well understood. This study evaluates the effect of trichloroethylene (TCE) concentration and common dissolved groundwater solutes on the rates of NZVI-promoted TCE dechlorination and H2 evolution in batch reactors. Both model systems and real groundwater are evaluated. The TCE reaction rate constant was unaffected by TCE concentration for [TCE] TCE concentration up to water saturation (8.4 mM). For [TCE] > or = 0.46 mM, acetylene formation increased, and the total amount of H2 evolved at the end of the particle reactive lifetime decreased with increasing [TCE], indicating a higher Fe0 utilization efficiency for TCE dechlorination. Common groundwater anions (5mN) had a minor effect on H2 evolution but inhibited TCE reduction up to 7-fold in increasing order of Cl- TCE reduction but increased acetylene production and decreased H2 evolution. NO3- present at > 3 mM slowed TCE dechlorination due to surface passivation. NO3- present at 5 mM stopped TCE dechlorination and H2 evolution after 3 days. Dissolved solutes accounted for the observed decrease of NZVI reactivity for TCE dechlorination in natural groundwater when the total organic content was small (< 1 mg/L).

  17. Development Of ABEC Column For Separation Of Tc-99 From Northstar Dissolved Target Solution

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C. [Argonne National Lab. (ANL), Argonne, IL (United States); Bennett, Megan E. [Argonne National Lab. (ANL), Argonne, IL (United States); Naik, Seema R. [Argonne National Lab. (ANL), Argonne, IL (United States); ling, lei [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, N-H. Linda [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-12-01

    Batch and column breakthrough experiments were performed to determine isotherms and mass-transfer parameters for adsorption of Tc on aqueous biphasic extraction chromatographic (ABEC) sorbent in two solutions: 200 g/L Mo, 5.1 M K+, 1 M OH-, and 0.1 M NO3- (Solution A) and 200 g/L Mo, 9.3 M K+, 5 M OH-, and 0.1 M NO3- (Solution B). Good agreement was found between the isotherm values obtained by batch and column breakthrough studies for both Solutions A and B. Potassium-pertechnetate intra-particle diffusivity on ABEC resin was estimated by VERSE simulations, and good agreement was found among a series of column-breakthrough experiments at varying flow velocities, column sizes, and technetium concentrations. However, testing of 10 cc cartridges provided by NorthStar with Solutions A and B did not give satisfactory results, as significant Tc breakthrough was observed and ABEC cartridge performance varied widely among experiments. These different experimental results are believed to be due to inconsistent preparation of the ABEC resin prior to packing and/or inconsistent packing.

  18. Conformational arrangement of dissolved humic substances. Influence of solution composition on association of humic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Conte, P.; Piccolo, A. [Univ. di Napoli Federico II, Portici (Italy). Dipt. di Scienze Chimico-Agrarie

    1999-05-15

    The characteristics and quantity of humic substances greatly affects the environmental fate of organic pollutants in soils and natural waters. The authors studied the conformational changes of humic and fulvic acids of different chemical nature by high-pressure size-exclusion chromatography (HPSEC) after dissolution in mobile phases differing in composition but constant in ionic strength. Modification of a neutral mobile phase by addition of methanol, hydrochloric acid, and acetic acid produced, in the order, a progressive decrease in molecular size. Size diminishing was shown by increasingly larger elution volumes at a refractive index detector and by concomitant reductions of peaks absorbance at a UV-vis detector. The decrease of molecular absorptivity (the phenomenon of hypochromism) proved that size reduction of dissolved humic substances was due more to disruption of an only apparent high-molecular-size arrangement into several smaller molecular associations than to coiling down of a macromolecular structure. The most significant conformational changes occurred in acidic mobile phases where hydrogen bondings formation was induced, suggesting that the large and easily disruptable humic conformation was held together predominantly by weak hydrophobic forces.

  19. Factors affecting total dissolved solids concentration of γ-ray-irradiated aqueous hexamethylenetetramine solution: a dosimetric study.

    Science.gov (United States)

    Sife-Eldeen, Kh A

    2014-12-01

    A new γ-ray-radiation dosimetric system (TDS-HMTA), comprising a 'total dissolved solids (TDS)' meter and 0.02 M aqueous hexamethylenetetramine (HMTA) solution, is introduced for medical and biological applications. Gamma-ray radiolysis of aqueous HTMA solutions increases the concentrations (ppm) of TDS, which is measured by the TDS meter. The effects of HMTA concentration, absorbed radiation dose, absorbed dose rate, and storage time on the TDS concentration of irradiated HMTA solutions were studied. It was found that 0.02 M aqueous HMTA solution yields the highest sensitivity to γ-ray-radiation according to TDS concentration measurements. The effect of absorbed radiation dose was studied in the range 1.64-435.5 kGy. The TDS concentration increases linearly up to the maximum of the studied absorbed radiation dose range (R(2) = 0.9965). The overall coefficient of variation (CV %) associated with TDS concentration measurements of 0.02 M HMTA solution as a function of absorbed dose was found to be 0.732%. The effect of dose rate on the TDS concentration was studied in the range 0.33-3.31 kGy/h. It was found, also, that the TDS concentration is relatively stable over a storage period of 144 h after irradiation with different doses. The tissue equivalency of 0.02 M aqueous HMTA solutions allow it to be used for radiation dose measurement during sterilization in human tissue banks. Therefore, this system (TDS-HMTA) could be considered as a promising candidate for γ-ray radiation dosimetry in technical, medical and research fields.

  20. Analytical solutions to dissolved contaminant plume evolution with source depletion during carbon dioxide storage.

    Science.gov (United States)

    Yang, Yong; Liu, Yongzhong; Yu, Bo; Ding, Tian

    2016-06-01

    Volatile contaminants may migrate with carbon dioxide (CO2) injection or leakage in subsurface formations, which leads to the risk of the CO2 storage and the ecological environment. This study aims to develop an analytical model that could predict the contaminant migration process induced by CO2 storage. The analytical model with two moving boundaries is obtained through the simplification of the fully coupled model for the CO2-aqueous phase -stagnant phase displacement system. The analytical solutions are confirmed and assessed through the comparison with the numerical simulations of the fully coupled model. Then, some key variables in the analytical solutions, including the critical time, the locations of the dual moving boundaries and the advance velocity, are discussed to present the characteristics of contaminant migration in the multi-phase displacement system. The results show that these key variables are determined by four dimensionless numbers, Pe, RD, Sh and RF, which represent the effects of the convection, the dispersion, the interphase mass transfer and the retention factor of contaminant, respectively. The proposed analytical solutions could be used for tracking the migration of the injected CO2 and the contaminants in subsurface formations, and also provide an analytical tool for other solute transport in multi-phase displacement system.

  1. Valuation of flexible solutions with alternative fuel cell energy sources

    Energy Technology Data Exchange (ETDEWEB)

    Haahtela, T.; Surakka, T.; Malinen, P. [Helsinki Univ. of Technology, Espoo (Finland). BIT Research Centre

    2009-07-01

    Fuel cells are an emerging technology with high potential, but also with significant market uncertainty. Fuel cells are currently in the transition from field trials to commercial introduction, and firms need to consider whether the technology fulfils the reliability and cost requirements of their current and upcoming products. This paper presented a framework to assist managers in finding the suitable valuation method for comparing different alternatives with emerging fuel cell technology. The dynamic valuation approaches of decision tree analysis, real options and system dynamics were discussed as they help in choosing the optimal timing and product structure over a long time period. Three examples of applications with fuel cells were briefly presented. The paper also addressed how the suggested valuation methods could be applied to them. These applications included maritime buoys; removable crisis management energy source container; and electrification of public transportation. It was concluded that the fuel cell technology has already become economically feasible in certain application areas. Improving technical reliability and cost reductions will make fuel cells even more competitive alternatives in new application areas. 9 refs., 1 tab., 1 fig.

  2. Generation of Hydroxyl Radicals from Dissolved Transition Metals in Surrogate Lung Fluid Solutions.

    Science.gov (United States)

    Vidrio, Edgar; Jung, Heejung; Anastasio, Cort

    2008-01-01

    Epidemiological research has linked exposure to atmospheric particulate matter (PM) to several adverse health effects, including cardiovascular and pulmonary morbidity and mortality. Despite these links, the mechanisms by which PM causes adverse health effects are poorly understood. The generation of hydroxyl radical (.OH) and other reactive oxygen species (ROS) through transition metal-mediated pathways is one of the main hypotheses for PM toxicity. In order to better understand the ability of particulate transition metals to produce ROS, we have quantified the amounts of .OH produced from dissolved iron and copper in a cell-free, surrogate lung fluid (SLF). We also examined how two important biological molecules, citrate and ascorbate, affect the generation of .OH by these metals. We have found that Fe(II) and Fe(III) produce little .OH in the absence of ascorbate and citrate, but that they efficiently make .OH in the presence of ascorbate and this is further enhanced when citrate is also added. In the presence of ascorbate, with or without citrate, the oxidation state of iron makes little difference on the amount of .OH formed after 24 hours. In the case of Cu(II), the production of .OH is greatly enhanced in the presence of ascorbate, but is inhibited by the addition of citrate. The mechanism for this effect is unclear, but appears to involve formation of a citrate-copper complex that is apparently less reactive than free, aquated copper in either the generation of HOOH or in the Fenton-like reaction of copper with HOOH to make .OH. By quantifying the amount of .OH that Fe and Cu can produce in surrogate lung fluid, we have provided a first step into being able to predict the amounts of .OH that can be produced in the human lung from exposure to PM containing known amounts of transition metals.

  3. Hydrogen as a renewable and sustainable solution in reducing global fossil fuel consumption

    Energy Technology Data Exchange (ETDEWEB)

    Midilli, Adnan; Dincer, Ibrahim [Energy Division, Mechanical Engineering Department, Nigde University, 51100 Nigde (Turkey); Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario L1H 7K4 (Canada)

    2008-08-15

    In this paper, hydrogen is considered as a renewable and sustainable solution for reducing global fossil fuel consumption and combating global warming and studied exergetically through a parametric performance analysis. The environmental impact results are then compared with the ones obtained for fossil fuels. In this regard, some exergetic expressions are derived depending primarily upon the exergetic utilization ratios of fossil fuels and hydrogen: the fossil fuel based global waste exergy factor, hydrogen based global exergetic efficiency, fossil fuel based global irreversibility coefficient and hydrogen based global exergetic indicator. These relations incorporate predicted exergetic utilization ratios for hydrogen energy from non-fossil fuel resources such as water, etc., and are used to investigate whether or not exergetic utilization of hydrogen can significantly reduce the fossil fuel based global irreversibility coefficient (ranging from 1 to +{infinity}) indicating the fossil fuel consumption and contribute to increase the hydrogen based global exergetic indicator (ranging from 0 to 1) indicating the hydrogen utilization at a certain ratio of fossil fuel utilization. In order to verify all these exergetic expressions, the actual fossil fuel consumption and production data are taken from the literature. Due to the unavailability of appropriate hydrogen data for analysis, it is assumed that the utilization ratios of hydrogen are ranged between 0 and 1. For the verification of these parameters, the variations of fossil fuel based global irreversibility coefficient and hydrogen based global exergetic indicator as the functions of fossil fuel based global waste exergy factor, hydrogen based global exergetic efficiency and exergetic utilization of hydrogen from non-fossil fuels are analyzed and discussed in detail. Consequently, if exergetic utilization ratio of hydrogen from non-fossil fuel sources at a certain exergetic utilization ratio of fossil fuels

  4. Effect of arsenic on the activity of oxygen dissolved in dilute liquid copper solutions

    Science.gov (United States)

    Walqui, H.; Seetharaman, S.; Staffansson, L. I.

    1985-06-01

    The influence of arsenic additions on the activity of oxygen in liquid copper was studied by the solid-electrolyte galvanic cell (-) Pt, W/Cu-O-As ∥ ZrO2-CaO ∥ NiO-Ni/Pt (+) in the temperature range 1373 to 1473 K. The activity coefficient of oxygen in liquid copper was found to be unaffected by the addition of arsenic. The interaction parameter values for group V B elements in the periodic table with respect to oxygen are discussed in the light of the solute interactions in copper.

  5. SOLID SOLUTION CARBIDES ARE THE KEY FUELS FOR FUTURE NUCLEAR THERMAL PROPULSION

    Science.gov (United States)

    Panda, Binayak; Hickman, Robert R.; Shah, Sandeep

    2005-01-01

    Nuclear thermal propulsion uses nuclear energy to directly heat a propellant (such as liquid hydrogen) to generate thrust for space transportation. In the 1960 s, the early Rover/Nuclear Engine for Rocket Propulsion Application (NERVA) program showed very encouraging test results for space nuclear propulsion but, in recent years, fuel research has been dismal. With NASA s renewed interest in long-term space exploration, fuel researchers are now revisiting the RoverMERVA findings, which indicated several problems with such fuels (such as erosion, chemical reaction of the fuel with propellant, fuel cracking, and cladding issues) that must be addressed. It is also well known that the higher the temperature reached by a propellant, the larger the thrust generated from the same weight of propellant. Better use of fuel and propellant requires development of fuels capable of reaching very high temperatures. Carbides have the highest melting points of any known material. Efforts are underway to develop carbide mixtures and solid solutions that contain uranium carbide, in order to achieve very high fuel temperatures. Binary solid solution carbides (U, Zr)C have proven to be very effective in this regard. Ternary carbides such as (U, Zr, X) carbides (where X represents Nb, Ta, W, and Hf) also hold great promise as fuel material, since the carbide mixtures in solid solution generate a very hard and tough compact material. This paper highlights past experience with early fuel materials and bi-carbides, technical problems associated with consolidation of the ingredients, and current techniques being developed to consolidate ternary carbides as fuel materials.

  6. Factors controlling the chemical composition of colloidal and dissolved fractions in soil solutions and the mobility of trace elements in soils

    Science.gov (United States)

    Gangloff, Sophie; Stille, Peter; Schmitt, Anne-Désirée; Chabaux, François

    2016-09-01

    The objectives of this study were to determine the processes and physico-chemical conditions that affect the composition of the soil solutions of a forest soil and to elucidate their impact on the transport of major and trace elements through the colloidal (0.2 μm to 5 kDa) and dissolved (microbial activity influences the composition of the colloidal and dissolved fractions, and possibly enriches the colloidal fraction in Ca, Mn and P, diminishes the concentrations of Pb, V, Cr and Fe in the dissolved fraction, and changes the structure of organic carbon (OC). These results are important for a better understanding of the role of the colloidal and dissolved (pollutants and the bioavailability of nutrients for forested ecosystems.

  7. Dissolved plume attenuation with DNAPL source remediation, aqueous decay and volatilization — Analytical solution, model calibration and prediction uncertainty

    Science.gov (United States)

    Parker, Jack C.; Park, Eungyu; Tang, Guoping

    2008-11-01

    A vertically-integrated analytical model for dissolved phase transport is described that considers a time-dependent DNAPL source based on the upscaled dissolution kinetics model of Parker and Park with extensions to consider time-dependent source zone biodecay, partial source mass reduction, and remediation-enhanced source dissolution kinetics. The model also considers spatial variability in aqueous plume decay, which is treated as the sum of aqueous biodecay and volatilization due to diffusive transport and barometric pumping through the unsaturated zone. The model is implemented in Excel/VBA coupled with (1) an inverse solution that utilizes prior information on model parameters and their uncertainty to condition the solution, and (2) an error analysis module that computes parameter covariances and total prediction uncertainty due to regression error and parameter uncertainty. A hypothetical case study is presented to evaluate the feasibility of calibrating the model from limited noisy field data. The results indicate that prediction uncertainty increases significantly over time following calibration, primarily due to propagation of parameter uncertainty. However, differences between the predicted performance of source zone partial mass reduction and the known true performance were reasonably small. Furthermore, a clear difference is observed between the predicted performance for the remedial action scenario versus that for a no-action scenario, which is consistent with the true system behavior. The results suggest that the model formulation can be effectively utilized to assess monitored natural attenuation and source remediation options if careful attention is given to model calibration and prediction uncertainty issues.

  8. Effect of fuel characteristics on synthesis of calcium hydroxyapatite by solution combustion route

    Indian Academy of Sciences (India)

    Samir K Ghosh; Asit Prakash; Someswar Datta; Sujit K Roy; Debabrata Basu

    2010-02-01

    The effect of fuel characteristics on the processing of nano sized calcium hydroxyapatite (HA) fine powders by the solution combustion technique is reported. Urea, glycine and glucose were used as fuels in this study. By using different combinations of urea and glycine fuels and occasional addition of small amounts of highly water-soluble glucose, the flame temperature (f) of the process as well as product characteristics could be controlled easily. The powders obtained by this modified solution combustion technique were characterized by XRD, FTIR spectroscopy, SEM, FESEM–EDX, particle size analyser (PSD) and specific surface area (SSA) measurements. The particle size of phase pure HA powder was found to be < 20 nm in this investigation. The effects of glucose addition with stoichiometric ( = 1) and fuel excess ( > 1) urea and glycine precursor batches were investigated separately.

  9. A simple and rapid method for monitoring dissolved oxygen in water with a submersible microbial fuel cell (SBMFC)

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2012-01-01

    Asubmersiblemicrobial fuel cell (SBMFC) was developed as a biosensor forin situand real time monitoring of dissolvedoxygen (DO) in environmental waters. Domestic wastewater was utilized as sole fuel for powering the sensor. The sensor performance was firstly examined with tap water at varying DO ...

  10. Development of alkaline solution separations for potential partitioning of used nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, Gordon D [Los Alamos National Laboratory; Runde, Wolfgang H [Los Alamos National Laboratory; Goff, George S [Los Alamos National Laboratory

    2009-01-01

    The processing of used nuclear fuel in alkaline solution provides potentially useful new selectivity for separating the actinides from each other and f rom the fission products. Over the ast decade, several research teams around the world have considered dissolution of used fuel in alkaline solution and further partitioning in this medium as an alternative to acid dissolution. The chemistry of the actinides and fission products in alkaline soilltion requires extensive investigation to more carefully evaluate its potential for developing useful separation methods for used nuclear fueI.

  11. Analytical Solution of Fick's Law of the TRISO-Coated Fuel Particles and Fuel Elements in Pebble-Bed High Temperature Gas-Cooled Reactors

    Institute of Scientific and Technical Information of China (English)

    CAO Jian-Zhu; FANG Chao; SUN Li-Feng

    2011-01-01

    T wo kinds of approaches are built to solve the fission products diffusion models (Fick's equation) based on sphere fuel particles and sphere fuel elements exactly. Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented, respectively. The analytica,solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation.In the fuel element system, a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element. Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations.%@@ Two kinds of approaches are built to solve the fission products diffusion models(Fick's equation) based on sphere fuel particles and sphere fuel elements exactly.Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented,respectively.The analytical solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation.In the fuel element system,a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element.Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations.

  12. Removal of triazine-based pollutants from water by carbon nanotubes: Impact of dissolved organic matter (DOM) and solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-12-01

    Adsorption of organic pollutants by carbon nanotubes (CNTs) in the environment or removal of pollutants during water purification require deep understanding of the impacts of the presence of dissolved organic matter (DOM). DOM is an integral part of environmental systems and plays a key role affecting the behavior of organic pollutants. In this study, the effects of solution chemistry (pH and ionic strength) and the presence of DOM on the removal of atrazine and lamotrigine by single-walled CNTs (SWCNTs) was investigated. The solubility of atrazine slightly decreased (∼5%) in the presence of DOM, whereas that of lamotrigine was significantly enhanced (by up to ∼70%). Simultaneous introduction of DOM and pollutant resulted in suppression of removal of both atrazine and lamotrigine, which was attributed to DOM-pollutant competition or blockage of adsorption sites by DOM. However the decrease in removal of lamotrigine was also a result of its complexation with DOM. Pre-introduction of DOM significantly reduced pollutant adsorption by the SWCNTs, whereas introduction of DOM after the pollutant resulted in the release of adsorbed atrazine and lamotrigine from the SWCNTs. These data imply that DOM exhibits higher affinity for the adsorption sites than the triazine-based pollutants. In the absence of DOM atrazine was a more effective competitor than lamotrigine for adsorption sites in SWCNTs. However, competition between pollutants in the presence of DOM revealed lamotrigine as the better competitor. Our findings help unravel the complex DOM-organic pollutant-CNT system and will aid in CNT-implementation in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    Science.gov (United States)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-01-01

    “Clumped-isotope” thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope “clumps”). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals.We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect.Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3− and CO32−. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many

  14. Direct borohydride fuel cell: Main issues met by the membrane-electrodes-assembly and potential solutions

    Science.gov (United States)

    Demirci, Umit B.

    The direct borohydride fuel cell (DBFC) is a fuel cell for which there is consensus about its promising commercial future as a portable power system. However, its development faces three main issues: the borohydride hydrolysis (issue 1) and crossover (issue 2), and the cost (issue 3). These issues are encountered by the membrane-electrodes-assembly. By a discussion around these three issues, the present paper reviews the experimental aspects. The discussion stresses on the opportunities of improvements and reviews the potential solutions that are proposed in the open literature. For each issue, the best solution seems to be a combination of improvements. The issue 1 may be solved thanks to a gold-based anode catalyst and an optimized fuel. The solution to the issue 2 may be a more efficient membrane combined with an optimized fuel and an inactive-towards-borohydride cathode catalyst like MnO 2. Regarding the issue 3, cheaper materials and better fuel use efficiency are the keys. The DBFC is still in a development phase with a small number of years of R&D invested and it appears that there are real improvement opportunities on the path of the DBFC marketing.

  15. A membraneless microscale fuel cell using non-noble catalysts in alkaline solution

    Science.gov (United States)

    Sung, Woosuk; Choi, Jin-Woo

    This paper presents the development of a novel liquid-based microscale fuel cell using non-noble catalysts in an alkaline solution. The developed fuel cell is based on a membraneless structure. The operational complications of a proton exchange membrane lead the development of a fuel cell with the membraneless structure. Non-noble metals with relatively mild catalytic activity, nickel hydroxide and silver oxide, were employed as anode and cathode catalysts to minimize the effect of cross-reactions with the membraneless structure. Along with nickel hydroxide and silver oxide, methanol and hydrogen peroxide were used as a fuel at anode and an oxidant at cathode. With a fuel mixture flow rate of 200 μl min -1, a maximum output power density of 28.73 μW cm -2 was achieved. The developed fuel cell features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable applications.

  16. Cost and fuel efficient SCR-only solution for post-2010 HD emission standards

    NARCIS (Netherlands)

    Cloudt, R.P.M.; Willems, F.P.T.; Heijden, P.V.A.M. van der

    2009-01-01

    A promising SCR-only solution is presented to meet post-2010 NOx emission targets for heavy duty applications. The proposed concept is based on an engine from a EURO IV SCR application, which is considered optimal with respect to fuel economy and costs. The addition of advanced SCR after treatment c

  17. Demonstration of a SANEX Process in Centrifugal Contactors using the CyMe{sub 4}-BTBP Molecule on a Genuine Fuel Solution

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, D.; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commiss, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, (Germany); Foreman, M.R.S. [Univ Reading, Dept Chem, Reading RG6 6AD, Berks, (United Kingdom); Geist, A. [Forschungszentrum Karlsruhe, Inst Nukl Entsorgung, D-76021 Karlsruhe, (Germany); Modolo, G. [Forschungszentrum Julich, Inst Energy Res Safety Res and Reactor Technol, D-52425 Julich, (Germany); Sorel, C. [Commissariat Energie Atom Valrho, CEA, DRCP SCPS, F-30207 Bagnols Sur Ceze, (France)

    2009-07-01

    Efficient recovery of minor actinides from a genuine spent fuel solution has been successfully demonstrated by the CyMe{sub 4}-BTBP/DMDOHEMA extractant mixture dissolved in octanol. The continuous countercurrent process, in which actinides(III) were separated from lanthanides(III), was carried out in laboratory centrifugal contactors using an optimized flow-sheet involving a total of 16 stages. The process was divided into 9 stages for extraction from a 2 M nitric acid feed solution, 3 stages for lanthanide scrubbing, and 4 stages for actinide back-extraction. Excellent feed decontamination factors for Am (7000) and Cm (1000) were obtained and the recoveries of these elements were higher than 99.9%. More than 99.9% of the lanthanides were directed to the raffinate except Gd for which 0.32% was recovered in the product. (authors)

  18. Corrosion of used nuclear fuel in aqueous perchlorate and carbonate solutions

    Science.gov (United States)

    Shoesmith, D. W.; Sunder, S.; Bailey, M. G.; Miller, N. H.

    1996-01-01

    The corrosion of used fuel was investigated using electrodes constructed from fuel pins discharged from the Pickering, Bruce and Darlington CANDU reactors, and compared to the corrosion behaviour observed on unirradiated UO 2 and SIMFUEL. Experiments were carried out in solutions of NaClO 4 (pH˜ 9.5) in the presence and absence of (a) substantial concentrations of sodium carbonate, and (b) additional external gamma fields. Used fuel electrodes reached oxidizing corrosion potentials ( ECORR) rapidly compared with unirradiated UO 2 electrodes. However, optical and SEM examinations showed no evidence for rapid oxidative dissolution. This reaction, expected to be fast since high values of ECORR are observed, appears to be blocked by the accumulation of secondary phases in grain boundaries. The oxidation and dissolution behaviour of used fuel is determined predominantly by (i) the dose rate in solution near the fuel surface, (ii) the extent of burnup (which determines the degree of fission product doping), and (iii) the degree of non-stoichiometry.

  19. Adsorption of Pb and Zn from binary metal solutions and in the presence of dissolved organic carbon by DTPA-functionalised, silica-coated magnetic nanoparticles.

    Science.gov (United States)

    Hughes, D L; Afsar, A; Harwood, L M; Jiang, T; Laventine, D M; Shaw, L J; Hodson, M E

    2017-09-01

    The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L(-1) Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0.025 mmol L(-1)) on the adsorption of variable concentrations (0-0.045 mmol L(-1)) of the other metal (Pb or Zn, respectively) adsorption was well modelled by linear isotherms (R(2) > 0.60; p ≤ 0.001) and Pb was preferentially adsorbed relative to Zn. In dissolved organic carbon experiments, the presence of fulvic acid (0, 2.1 and 21 mg DOC L(-1)) reduced Pb and Zn adsorption from 0.01, 0.1 and 1.0 mmol L(-1) solutions. However, even at 21 mg DOC L(-1) fulvic acid, extraction efficiencies from 0.01 to 0.1 mmol L(-1) solutions remained >80% (Pb) and >50% (Zn). Decreases in extraction efficiency were significant between initial metal concentrations of 0.1 and 1.0 mmol L(-1) indicating that at metal loadings between c. 100 mg kg(-1) and 300 mg kg(-1) occupancy of adsorption sites began to limit further adsorption. The nanoparticles have the potential to perform effectively as metal adsorbents in systems containing more than one metal and dissolved organic carbon at a range of pH values. Copyright © 2017. Published by Elsevier Ltd.

  20. Determination of plutonium resent in highly radioactive irradiated fuel solution by spectrophotometric method

    Energy Technology Data Exchange (ETDEWEB)

    Dhamodharam, Krishnan [Reprocessing Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Pius, Anitha [The Gandhigram Rural Institute - Deemed University, Gandhigram (India)

    2016-06-15

    A simple and rapid spectrophotometric method has been developed to enable the determination of plutonium concentration in an irradiated fuel solution in the presence of all fission products. An excess of ceric ammonium nitrate solution was employed to oxidize all the valence states of plutonium to +6 oxidation state. Interference due to the presence of fission products such as ruthenium and zirconium, and corrosion products such as iron in the envisaged concentration range, as in the irradiated fuel solution, was studied in the determination of plutonium concentration by the direct spectrophotometric method. The stability of plutonium in +6 oxidation state was monitored under experimental conditions as a function of time. Results obtained are reproducible, and this method is applicable to radioactive samples resulting before the solvent extraction process during the reprocessing of fast reactor spent fuel. An analysis of the concentration of plutonium shows a relative standard deviation of <1.2% in standard as well as in simulated conditions. This reflects the fast reactor fuel composition with respect to uranium, plutonium, fission products such as ruthenium and zirconium, and corrosion products such as iron.

  1. Fuel cell vehicles: technological solution; La pila de combustible en los vehiculos automoviles: un reto tecnologico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Martinez, J. M.

    2004-07-01

    Recently it takes a serious look at fuel cell vehicles, a leading candidate for next-generation vehicle propulsion systems. The green house effect and air quality are pressing to the designers of internal combustion engine vehicles, owing to the manufacturers to find out technological solutions in order to increase the efficiency and reduce emissions from the vehicles. On the other hand, energy source used by currently propulsion systems is not renewable, the well are limited and produce CO{sub 2} as a product from the combustion process. In that situation, why fuel cell is an alternative of internal combustion engine?.

  2. Fuel reprocessing tank

    Energy Technology Data Exchange (ETDEWEB)

    Gonda, Sumitora

    1998-10-09

    A tank of the present invention for spent fuels comprises a stainless steel tank main body for storing a highly corrosive dissolving solution, a steam jet pump disposed to the inside of the tank main body for transferring the dissolving solution to the outside of the tank main body and pipelines connecting them. With such a constitution, abnormal abrasion and drag of mechanical parts are less caused. In addition, a cleaning nozzle and a cleaning liquid pipeline which eliminates clogging of a sucking port of the steam jet pump if clogging is caused by sludges are disposed thereby enabling to avoid possibility of clogging. (T.M.)

  3. Modelling of solid polymer and direct methanol fuel cells: Phenomenological equations and analytical solutions

    Science.gov (United States)

    Kauranen, P. S.

    1993-04-01

    In the solid state concept of a direct methanol fuel cell (DMFC), methanol is directly oxidized at the anode of a solid polymer electrolyte fuel cell (SPEFC). Mathematical modelling of the transport and reaction phenomena within the electrodes and the electrolyte membrane is needed in order to get a closer insight into the operation of the fuel cell. In the work, macro-homogenous porous electrode and dilute solution theories are used to derive the phenomenological equations describing the transport and reaction mechanisms in a SPEFC single cell. The equations are first derived for a conventional H2/air SPEFC, and then extended for a DMFC. The basic model is derived in a one dimensional form in which it is assumed that species transport take place only in the direction crossing the cell sandwich. In addition, two dimensional descriptions of the catalyst layer are reviewed.

  4. An alternative solution for heavy liquid metal cooled reactors fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Vitale Di Maio, Damiano, E-mail: damiano.vitaledimaio@uniroma1.it [“SAPIENZA” University of Rome – DIAEE, Corso Vittorio Emanuele II, 244, 00186 Rome (Italy); Cretara, Luca; Giannetti, Fabio [“SAPIENZA” University of Rome – DIAEE, Corso Vittorio Emanuele II, 244, 00186 Rome (Italy); Peluso, Vincenzo [“ENEA”, Via Martiri di Monte Sole 4, 40129 Bologna (Italy); Gandini, Augusto [“SAPIENZA” University of Rome – DIAEE, Corso Vittorio Emanuele II, 244, 00186 Rome (Italy); Manni, Fabio [“SRS Engineering Design S.r.l.”, Vicolo delle Palle 25-25/b, 00186 Rome (Italy); Caruso, Gianfranco [“SAPIENZA” University of Rome – DIAEE, Corso Vittorio Emanuele II, 244, 00186 Rome (Italy)

    2014-10-15

    Highlights: • A new fuel assembly locking system for heavy metal cooled reactor is proposed. • Neutronic, mechanical and thermal-hydraulic evaluations of the system behavior have been performed. • A comparison with other solutions has been presented. - Abstract: In the coming future, the electric energy production from nuclear power plants will be provided by both thermal reactors and fast reactors. In order to have a sustainable energy production through fission reactors, fast reactors should provide an increasing contribution to the total electricity production from nuclear power plants. Fast reactors have to achieve economic and technical targets of Generation IV. Among these reactors, Sodium cooled Fast Reactors (SFRs) and Lead cooled Fast Reactors (LFRs) have the greatest possibility to be developed as industrial power plants within few decades. Both SFRs and LFRs require a great R and D effort to overcome some open issues which affect the present designs (e.g. sodium-water reaction for the SFRs, erosion/corrosion for LFRs, etc.). The present paper is mainly focused on LFR fuel assembly (FA) design: issues linked with the high coolant density of lead or lead–bismuth eutectic cooled reactors have been investigated and an innovative solution for the core mechanical design is here proposed and analyzed. The solution, which foresees cylindrical fuel assemblies and exploits the buoyancy force due to the lead high density, allows to simplify the FAs locking system, to reduce their length and could lead to a more uniform neutron flux distribution.

  5. Used Fuel Logistics: Decades of Experience with transportation and Interim storage solutions

    Energy Technology Data Exchange (ETDEWEB)

    Orban, G.; Shelton, C.

    2015-07-01

    Used fuel inventories are growing worldwide. While some countries have opted for a closed cycle with recycling, numerous countries must expand their interim storage solutions as implementation of permanent repositories is taking more time than foreseen. In both cases transportation capabilities will have to be developed. AREVA TN has an unparalleled expertise with transportation of used fuel. For more than 50 years AREVA TN has safely shipped more than 7,000 used fuel transport casks. The transportation model that was initially developed in the 1970s has been adapted and enhanced over the years to meet more restrictive regulatory requirements and evolving customer needs, and to address public concerns. The numerous “lessons learned” have offered data and guidance that have allowed for also efficient and consistent improvement over the decades. AREVA TN has also an extensive experience with interim dry storage solutions in many countries on-site but also is working with partners to developed consolidated interim storage facility. Both expertise with storage and transportation contribute to safe, secure and smooth continuity of the operations. This paper will describe decades of experience with a very successful transportation program as well as interim storage solutions. (Author)

  6. A new approach to determine {sup 147}Pm in irradiated fuel solutions

    Energy Technology Data Exchange (ETDEWEB)

    Brennetot, R.; Stadelmann, G.; Caussignac, C.; Gombert, C.; Fouque, M.; Lamouroux, Ch. [CEA, Dept Chim Phys, Serv Etud Comportement Radionucleides, Lab Anal Nucl Isotop et Elementaires, Ctr Etud Sacl, F-91191 Gif Sur Yvette, (France)

    2009-07-01

    Developments carried out in the Laboratory of Isotopic Nuclear and Elementary Analyses in order to quantify {sup 147}Pm in spent nuclear fuels analyzed at the CEA within the framework of the Burn Up Credit research program for neutronic code validation are presented here. This determination is essential for safety-criticality Studies. The quantity and the nature of the radionuclides in irradiated fuel solutions force LIS to separate the elements of interest before measuring their isotopic content by mass spectrometry. The main objective of this study is to modify the separation protocol used in our laboratory in order to recover and to measure the {sup 147}Pm at the same time as the other lanthanides and actinides determined by mass spectrometry. A very complete study oil synthetic solution (containing or not {sup 147}Pm) Was undertaken in order to determine the yield of the various stages of separation carried out before obtaining the isolated Pm fraction from the whole of the elements present in the spent fuel Solutions. With the lack of natural tracer to carry out the measurement with the isotope dilution technique, the great number of isotopes in fuel, the originality of this work tests oil the use of another present lanthanide in fuel to define the output of separation. The yields were measured at the conclusion of each stage of separation with two others lanthanides in order to show that one of them could be used as a tracer to correct the measurement of the {sup 147}Pm with the separation yield. The total yield (at the conclusion of the two stages of separation) was measured at the same time by ICP-MS and liquid scintillation. This last determination made it possible to validate the use of the Sm-147 (natural) to measure the {sup 147}Pm in ICP-MS since the outputs determined in liquid scintillation and ICP-MS (starting from the radioactive decrease of the source having been used to make the synthetic solution) were equivalent. It is the first time that such

  7. Distributions of 14 elements on 60 selected absorbers from two simulant solutions (acid-dissolved sludge and alkaline supernate) for Hanford HLW Tank 102-SY

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1993-10-01

    Sixty commercially available or experimental absorber materials were evaluated for partitioning high-level radioactive waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, and a series of liquid extractants sorbed on porous support-beads. The distributions of 14 elements onto each absorber were measured from simulated solutions that represent acid-dissolved sludge and alkaline supernate solutions from Hanford high-level waste (HLW) Tank 102-SY. The selected elements, which represent fission products (Ce, Cs, Sr, Tc, and Y); actinides (U, Pu, and Am); and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr), were traced by radionuclides and assayed by gamma spectrometry. Distribution coefficients for each of the 1680 element/absorber/solution combinations were measured for dynamic contact periods of 30 min, 2 h, and 6 h to provide sorption kinetics information for the specified elements from these complex media. More than 5000 measured distribution coefficients are tabulated.

  8. Impact of air-borne or canopy-derived dissolved organic carbon (DOC) on forest soil solution DOC in Flanders, Belgium

    Science.gov (United States)

    Verstraeten, Arne; De Vos, Bruno; Neirynck, Johan; Roskams, Peter; Hens, Maarten

    2014-02-01

    Dissolved organic carbon (DOC) in the soil solution of forests originates from a number of biologically and/or biochemically mediated processes, including litter decomposition and leaching, soil organic matter mineralization, root exudation, mucilage and microbial activity. A variable amount of DOC reaches the forest floor through deposition, but limited information is available about its impact on soil solution DOC. In this study, trends and patterns of soil solution DOC were evaluated in relation to deposition of DOC over an 11-year period (2002-2012) at five ICP Forests intensive monitoring plots in Flanders, northern Belgium. Trend analysis over this period showed an increase of soil solution DOC concentrations for all observed depth intervals. Fluxes of DOC increased in the organic layer, but were nearly stable in the mineral soil. Annual leaching losses of DOC were higher in coniferous (55-61 kg C ha-1) compared to deciduous plots (19-30 kg C ha-1) but embody less than 0.05% of total 1-m soil organic C stocks. Temporal deposition patterns could not explain the increasing trends of soil solution DOC concentrations. Deposition fluxes of DOC were strongly correlated with soil solution fluxes of DOC, but their seasonal peaks were not simultaneous, which confirmed that air-borne or canopy-derived DOC has a limited impact on soil solution DOC.

  9. Taxonomy of Means and Ends in Aquaculture Production—Part 2: The Technical Solutions of Controlling Solids, Dissolved Gasses and pH

    Directory of Open Access Journals (Sweden)

    Bjorgvin Vilbergsson

    2016-09-01

    Full Text Available In engineering design, knowing the relationship between the means (technique and the end (desired function or outcome is essential. The means in Aquaculture are technical solutions like airlifts that are used to achive desired functionality (an end like controlling dissolved gasses. In previous work, the authors identified possible functions by viewing aquaculture production systems as transformation processes in which inputs are transformed by treatment techniques (means and produce outputs (ends. The current work creates an overview of technical solutions of treatment functions for both design and research purposes. A comprehensive literature review of all areas of technical solutions is identified and categorized into a visual taxonomy of the treatment functions for controlling solids, controlling dissolved gasses and controlling pH alkalinity and hardness. This article is the second in a sequence of four and partly presents the treatments functions in the taxonomy. The other articles in this series present complementary aspects of this research: Part 1, A transformational view on aquaculture and functions divided into input, treatment and output functions; Part 2, The current taxonomy paper; Part 3, The second part of the taxonomy; and Part 4, Mapping of the means (techniques for multiple treatment functions.

  10. Supply Chain-Based Solution to Prevent Fuel Tax Evasion: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Capps, Gary J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Franzese, Oscar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Lascurain, Mary Beth [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Siekmann, Adam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Barker, Alan M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Electrical and Electronics Systems Research Division

    2016-07-28

    The primary source of funding for the United States transportation system is derived from motor fuel and other highway use taxes. Loss of revenue attributed to fuel-tax evasion has been assessed to be somewhere between 1 billion and 3 billion per year. Any solution that addresses this problem needs to include not only the tax-collection agencies and auditors, but also the carriers transporting oil products and the carriers customers. This report presents a system developed by the Oak Ridge National Laboratory (ORNL) for the Federal Highway Administration which has the potential to reduce or eliminate many fuel-tax evasion schemes. The solution balances the needs of tax-auditors and those of the fuel-hauling companies and their customers. The system has three main components. The on-board subsystem combined sensors, tracking and communication devices, and software (the on-board Evidential Reasoning System, or obERS) to detect, monitor, and geo-locate the transfer of fuel among different locations. The back office sub-system (boERS) used self-learning algorithms to determine the legitimacy of the fuel loading and offloading (important for tax auditors) and detect potential illicit operations such as fuel theft (important for carriers and their customers, and may justify the deployment costs). The third sub-system, the Fuel Distribution and Auditing System or FDAS, is a centralized database, which together with a user interface allows tax auditors to query the data submitted by the fuel-hauling companies and correlate different parameters to quickly identify any anomalies. Industry partners included Barger Transport of Weber City, Virginia (fleet); Air-Weigh, of Eugene, Oregon (and their wires and harnesses); Liquid Bulk Tank (LBT) of Omaha, Nebraska (three five-compartment trailers); and Innovative Software Engineering (ISE) of Coralville, Iowa(on-board telematics device and back-office system). ORNL conducted a pilot test with the three instrumented vehicles

  11. Supply Chain-Based Solution to Prevent Fuel Tax Evasion: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Capps, Gary J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Franzese, Oscar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Lascurain, Mary Beth [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Siekmann, Adam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering and Transportation Sciences Division; Barker, Alan M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Electrical and Electronics Systems Research Division

    2016-07-28

    The primary source of funding for the United States transportation system is derived from motor fuel and other highway use taxes. Loss of revenue attributed to fuel-tax evasion has been assessed to be somewhere between 1 billion and 3 billion per year. Any solution that addresses this problem needs to include not only the tax-collection agencies and auditors, but also the carriers transporting oil products and the carriers customers. This report presents a system developed by the Oak Ridge National Laboratory (ORNL) for the Federal Highway Administration which has the potential to reduce or eliminate many fuel-tax evasion schemes. The solution balances the needs of tax-auditors and those of the fuel-hauling companies and their customers. The system has three main components. The on-board subsystem combined sensors, tracking and communication devices, and software (the on-board Evidential Reasoning System, or obERS) to detect, monitor, and geo-locate the transfer of fuel among different locations. The back office sub-system (boERS) used self-learning algorithms to determine the legitimacy of the fuel loading and offloading (important for tax auditors) and detect potential illicit operations such as fuel theft (important for carriers and their customers, and may justify the deployment costs). The third sub-system, the Fuel Distribution and Auditing System or FDAS, is a centralized database, which together with a user interface allows tax auditors to query the data submitted by the fuel-hauling companies and correlate different parameters to quickly identify any anomalies. Industry partners included Barger Transport of Weber City, Virginia (fleet); Air-Weigh, of Eugene, Oregon (and their wires and harnesses); Liquid Bulk Tank (LBT) of Omaha, Nebraska (three five-compartment trailers); and Innovative Software Engineering (ISE) of Coralville, Iowa(on-board telematics device and back-office system). ORNL conducted a pilot test with the three instrumented vehicles

  12. Underestimation of nuclear fuel burnup – theory, demonstration and solution in numerical models

    Directory of Open Access Journals (Sweden)

    Gajda Paweł

    2016-01-01

    Full Text Available Monte Carlo methodology provides reference statistical solution of neutron transport criticality problems of nuclear systems. Estimated reaction rates can be applied as an input to Bateman equations that govern isotopic evolution of reactor materials. Because statistical solution of Boltzmann equation is computationally expensive, it is in practice applied to time steps of limited length. In this paper we show that simple staircase step model leads to underprediction of numerical fuel burnup (Fissions per Initial Metal Atom – FIMA. Theoretical considerations indicates that this error is inversely proportional to the length of the time step and origins from the variation of heating per source neutron. The bias can be diminished by application of predictor-corrector step model. A set of burnup simulations with various step length and coupling schemes has been performed. SERPENT code version 1.17 has been applied to the model of a typical fuel assembly from Pressurized Water Reactor. In reference case FIMA reaches 6.24% that is equivalent to about 60 GWD/tHM of industrial burnup. The discrepancies up to 1% have been observed depending on time step model and theoretical predictions are consistent with numerical results. Conclusions presented in this paper are important for research and development concerning nuclear fuel cycle also in the context of Gen4 systems.

  13. Application of extraction chromatography to the separation of thorium and uranium dissolved in a solution of high salt concentration.

    Science.gov (United States)

    Fujiwara, Asako; Kameo, Yutaka; Hoshi, Akiko; Haraga, Tomoko; Nakashima, Mikio

    2007-01-26

    Extraction chromatography with commercially available UTEVA resin (for uranium and tetravalent actinide) was applied for the separation of Th and U from control solutions prepared from a multi-element control solution and from sample solutions of solidified simulated waste. Thorium and U in control solutions with 1-5mol/dm(3) HNO(3) were extracted with UTEVA resin and recovered with a solution containing 0.1mol/dm(3) HNO(3) and 0.05mol/dm(3) oxalic acid to be separated from the other metallic elements. Extraction behavior of U in the sample solutions was similar to that in the control solutions, but extraction of Th was dependent on the concentration of HNO(3). Thorium was extracted from 5mol/dm(3) HNO(3) sample solutions but not from 1mol/dm(3) HNO(3) sample solutions. We conjecture that thorium fluoride formation interferes with extraction of Th. Addition of Al(NO(3))(3) and Fe(NO(3))(3), which have higher stability constant with fluoride ion than Th, does improve extractability of Th from 1mol/dm(3) HNO(3) sample solution.

  14. Dinitrogen fixation and dissolved organic nitrogen fueled primary production and particulate export during the VAHINE mesocosm experiment (New Caledonia lagoon)

    Science.gov (United States)

    Berthelot, H.; Moutin, T.; L'Helguen, S.; Leblanc, K.; Hélias, S.; Grosso, O.; Leblond, N.; Charrière, B.; Bonnet, S.

    2015-07-01

    In the oligotrophic ocean characterized by nitrate (NO3-) depletion in surface waters, dinitrogen (N2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. In this study, we deployed large in situ mesocosms in New Caledonia in order to investigate (1) the contribution of N2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON), i.e., whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (PO43-) in order to prevent phosphorus (P) limitation and promote N2 fixation. The diazotrophic community was dominated by diatom-diazotroph associations (DDAs) during the first part of the experiment for 10 days (P1) followed by the unicellular N2-fixing cyanobacteria UCYN-C for the last 9 days (P2) of the experiment. N2 fixation rates averaged 9.8 ± 4.0 and 27.7 ± 8.6 nmol L-1 d-1 during P1 and P2, respectively. NO3- concentrations ( 0.05) during P1 (9.0 ± 3.3 %) and P2 (12.6 ± 6.1 %). However, the e ratio that quantifies the efficiency of a system to export particulate organic carbon (POCexport) compared to PP (e ratio = POCexport/PP) was significantly higher (p efficient at promoting C export than the production sustained by DDAs. During P1, PON was stable and the total amount of N provided by N2 fixation (0.10 ± 0.02 μmol L-1) was not significantly different (p > 0.05) from the total amount of PON exported (0.10 ± 0.04 μmol L-1), suggesting a rapid and probably direct export of the recently fixed N2 by the DDAs. During P2, both PON concentrations and PON export increased in the mesocosms by a factor 1.5-2. Unlike in P1, this PON production was not totally explained by the new N provided by N2 fixation. The use of DON, whose concentrations decreased significantly (p < 0.05) from 5.3 ± 0.5 μmol L-1 to 4.4 ± 0.5 μmol L-1, appeared to

  15. One-step solution combustion synthesis of pure Ni nanopowders with enhanced coercivity: The fuel effect

    Science.gov (United States)

    Khort, Alexander; Podbolotov, Kirill; Serrano-García, Raquel; Gun'ko, Yurii K.

    2017-09-01

    In this paper, we report a new modified one-step combustion synthesis technique for production of Ni metal nanoparticles. The main unique feature of our approach is the use of microwave assisted foam preparation. Also, the effect of different types of fuels (urea, citric acid, glycine and hexamethylenetetramine) on the combustion process and characteristics of resultant solid products were investigated. It is observed that the combination of microwave assisted foam preparation and using of hexamethylenetetramine as a fuel allows producing pure ferromagnetic Ni metal nanoparticles with enhanced coercivity (78 Oe) and high value of saturation magnetization (52 emu/g) by one-step solution combustion synthesis under normal air atmosphere without any post-reduction processing.

  16. Natural dissolved organic matter mobilizes Cd but does not affect the Cd uptake by the green algae Pseudokirchneriella subcapitata (Korschikov) in resin buffered solutions.

    Science.gov (United States)

    Verheyen, Liesbeth; Versieren, Liske; Smolders, Erik

    2014-09-01

    Natural dissolved organic matter (DOM) can have contrasting effects on metal bioaccumulation in algae because of complexation reactions that reduce free metal ion concentrations and because of DOM adsorption to algal surfaces which promote metal adsorption. This study was set up to reveal the role of different natural DOM samples on cadmium (Cd) uptake by the green algae Pseudokirchneriella subcapitata (Korschikov). Six different DOM samples were collected from natural freshwater systems and isolated by reverse osmosis. In addition, one (13)C enriched DOM sample was isolated from soil to trace DOM adsorption to algae. Algae were exposed to standardized solutions with or without these DOM samples, each exposed at equal DOM concentrations and at equal non-toxic Cd(2+) activity (∼4 nM) that was buffered with a resin. The DOM increased total dissolved Cd by factors 3-16 due to complexation reactions at equal Cd(2+) activity. In contrast, the Cd uptake was unaffected by DOM or increased maximally 1.6 fold ((13)C enriched DOM). The (13)C analysis revealed that maximally 6% of algal C was derived from DOM and that this can explain the small increase in biomass Cd. It is concluded that free Cd(2+) and not DOM-complexed Cd is the main bioavailable form of Cd when solution Cd(2+) is well buffered.

  17. Efficacy of a solution-based approach for making sodalite waste forms for an oxide reduction salt utilized in the reprocessing of used uranium oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J., E-mail: brian.riley@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Pierce, David A. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Frank, Steven M. [Idaho National Laboratory, Idaho Falls, ID 83402 (United States); Matyáš, Josef; Burns, Carolyne A. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2015-04-15

    This paper describes the various approaches evaluated for making solution-derived sodalite with a LiCl–Li{sub 2}O oxide reduction salt selected to dissolve used uranium oxide fuel so the uranium can be recovered and recycled. The approaches include modified sol–gel and solution-based synthesis processes. As-made products were mixed with 5 and 10 mass% of a Na{sub 2}O–B{sub 2}O{sub 3}–SiO{sub 2} glass binder and these, along with product without a binder, were heated using either a cold-press-and-sinter method or hot uniaxial pressing. The results demonstrate the limitation of sodalite yield due to the fast intermediate reactions between Na{sup +} and Cl{sup −} to form halite in solution and Li{sub 2}O and SiO{sub 2} to form lithium silicates (e.g., Li{sub 2}SiO{sub 3} or Li{sub 2}Si{sub 2}O{sub 5}) in the calcined and sintered pellets. The results show that pellets can be made with high sodalite fractions in the crystalline product (∼92 mass%) and low porosities using a solution-based approach and this LiCl–Li{sub 2}O salt but that the incorporation of Li into the sodalite is low.

  18. Fusion solution to dispose of spent nuclear fuel, transuranic elements, and highly enriched uranium

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Yousry E-mail: gohar@anl.gov

    2001-11-01

    The disposal of the nuclear spent fuel, the transuranic elements, and the highly enriched uranium represents a major problem under investigation by the international scientific community to identify the most promising solutions. The investigation of this paper focused on achieving the top rated solution for the problem, the elimination goal, which requires complete elimination for the transuranic elements or the highly enriched uranium, and the long-lived fission products. To achieve this goal, fusion blankets with liquid carrier, molten salts or liquid metal eutectics, for the transuranic elements and the uranium isotopes are utilized. The generated energy from the fusion blankets is used to provide revenue for the system. The long-lived fission products are fabricated into fission product targets for transmutation utilizing the neutron leakage from the fusion blankets. This paper investigated the fusion blanket designs for small fusion devices and the system requirements for such application. The results show that 334 MW of fusion power from D-T plasma for 30 years with an availability factor of 0.75 can dispose of the 70,000 tons of the U.S. inventory of spent nuclear fuel generated up to the year 2015. In addition, this fusion solution eliminates the need for a geological repository site, which is a major advantage. Meanwhile, such utilization of the fusion power will provide an excellent opportunity to develop fusion energy for the future.

  19. Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

    Science.gov (United States)

    Chiang, Po-Neng; Tong, Ou-Yang; Chiou, Chyow-San; Lin, Yu-An; Wang, Ming-Kuang; Liu, Cheng-Chung

    2016-01-15

    A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

  20. Modeling of the anode side of a direct methanol fuel cell with analytical solutions

    CERN Document Server

    Mosquera, Martín A

    2010-01-01

    In this work, analytical solutions were derived (for any methanol oxidation reaction order) for the profiles of methanol concentration and proton current density by assuming diffusion mass transport mechanism, Tafel kinetics, and fast proton transport in the anodic catalyst layer of a direct methanol fuel cell. An expression for the Thiele modulus that allows to express the anodic overpotential as a function of the cell current, and kinetic and mass transfer parameters was obtained. For high cell current densities, it was found that the Thiele modulus ($\\phi^2$) varies quadratically with cell current density; yielding a simple correlation between anodic overpotential and cell current density. Analytical solutions were derived for the profiles of both local methanol concentration in the catalyst layer and local anodic current density in the catalyst layer. Under the assumptions of the model presented here, in general, the local methanol concentration in the catalyst layer cannot be expressed as an explicit fun...

  1. Quantification of the dissolved inorganic carbon species and of the pH of alkaline solutions exposed to CO2 under pressure: a novel approach by Raman scattering.

    Science.gov (United States)

    Beuvier, Thomas; Calvignac, Brice; Bardeau, Jean-François; Bulou, Alain; Boury, Frank; Gibaud, Alain

    2014-10-07

    Dissolved inorganic carbon (DIC) content of aqueous systems is a key function of the pH, of the total alkanility (TA), and of the partial pressure of CO2. However, common analytical techniques used to determine the DIC content in water are unable to operate under high CO2 pressure. Here, we propose to use Raman spectroscopy as a novel alternative to discriminate and quantitatively monitor the three dissolved inorganic carbon species CO2(aq), HCO3(-), and CO3(2-) of alkaline solutions under high CO2 pressure (from P = 0 to 250 bar at T = 40 °C). In addition, we demonstrate that the pH values can be extracted from the molalities of CO2(aq) and HCO3(-). The results are in very good agreement with those obtained from direct spectrophotometric measurements using colored indicators. This novel method presents the great advantage over high pressure conventional techniques of not using breakable electrodes or reference additives and appears of great interest especially in marine biogeochemistry, in carbon capture and storage and in material engineering under high CO2 pressure.

  2. Surface micro-dissolve method of imparting self-cleaning property to cotton fabrics in NaOH/urea aqueous solution

    Science.gov (United States)

    Fan, Tao; Hu, Ruimin; Zhao, Zhenyun; Liu, Yiping; Lu, Ming

    2017-04-01

    A simple and economical micro-dissolved process of embedding titanium dioxide (TiO2) nanoparticles into surface zone of cotton fabrics was developed. TiO2 was coated on cotton fabrics in 7% wt NaOH/12% wt urea aqueous solution at low temperature. Photocatalytic efficiency of cotton fabrics treated with TiO2 nanoparticles was studied upon measuring the photocatalytic decoloration of Rhodamine B (RhB) under ultraviolet irradiation. Self-cleaning property of cotton fabric coated with TiO2 was evaluated with color depth of samples (K/S value). The treated fabrics were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FITR), tensile strength, stiffness and whiteness. The results indicated, TiO2 nanoparticles could be embedded on the surface layer of cotton fabrics throuth surface micro-dissolve method. Treated cotton fabrics possessed distinct photocatalytic efficiency and self-cleaning properties. Tensile strength and whiteness of modified cotton fabrics appeared moderately increasement.

  3. Attractive forces between hydrophobic solid surfaces measured by AFM on the first approach in salt solutions and in the presence of dissolved gases.

    Science.gov (United States)

    Azadi, Mehdi; Nguyen, Anh V; Yakubov, Gleb E

    2015-02-17

    Interfacial gas enrichment of dissolved gases (IGE) has been shown to cover hydrophobic solid surfaces in water. The atomic force microscopy (AFM) data has recently been supported by molecular dynamics simulation. It was demonstrated that IGE is responsible for the unexpected stability and large contact angle of gaseous nanobubbles at the hydrophobic solid-water interface. Here we provide further evidence of the significant effect of IGE on an attractive force between hydrophobic solid surfaces in water. The force in the presence of dissolved gas, i.e., in aerated and nonaerated NaCl solutions (up to 4 M), was measured by the AFM colloidal probe technique. The effect of nanobubble bridging on the attractive force was minimized or eliminated by measuring forces on the first approach of the AFM probe toward the flat hydrophobic surface and by using high salt concentrations to reduce gas solubility. Our results confirm the presence of three types of forces, two of which are long-range attractive forces of capillary bridging origin as caused by either surface nanobubbles or gap-induced cavitation. The third type is a short-range attractive force observed in the absence of interfacial nanobubbles that is attributed to the IGE in the form of a dense gas layer (DGL) at hydrophobic surfaces. Such a force was found to increase with increasing gas saturation and to decrease with decreasing gas solubility.

  4. Loofa sponge immobilized fungal biosorbent: a robust system for cadmium and other dissolved metal removal from aqueous solution.

    Science.gov (United States)

    Iqbal, M; Edyvean, R G J

    2005-10-01

    The potential of loofa sponge discs to immobilize fungal biomass of Phanerochaete chrysosporium (a known biosorbent) was investigated as a low cost biosorbent for the removal of Cd(II) ions from aqueous solution. A comparison of the biosorption of Cd(II) by immobilized and free fungal biomass from 10 to 500 mg l(-1) aqueous solutions showed an increase in uptake of over 19% when the biomass is immobilized (maximum biosorption capacity of 89 and 74 mg Cd(II) g(-1) biomass for immobilized and free biomass respectively at a solution pH of 6). Equilibrium was established within 1h and biosorption was well defined by the Langmuir isotherm model. The immobilized biomass could be regenerated using 50 mM HCl, with up to 99% metal recovery and reused in ten biosorption-desorption cycles without significant loss of capacity. This study suggests that such an immobilized biosorbent system has the potential to be used in the industrial removal/recovery of cadmium and other pollutant metal ions from aqueous solution.

  5. Mass transfer in fuel cells. [electron microscopy of components, thermal decomposition of Teflon, water transport, and surface tension of KOH solutions

    Science.gov (United States)

    Walker, R. D., Jr.

    1973-01-01

    Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.

  6. Adsorbed poly(aspartate) coating limits the adverse effects of dissolved groundwater solutes on Fe(0) nanoparticle reactivity with trichloroethylene.

    Science.gov (United States)

    Phenrat, Tanapon; Schoenfelder, Daniel; Kirschling, Teresa L; Tilton, Robert D; Lowry, Gregory V

    2015-08-02

    For in situ groundwater remediation, polyelectrolyte-modified nanoscale zerovalent iron particles (NZVIs) have to be delivered into the subsurface, where they degrade pollutants such as trichloroethylene (TCE). The effect of groundwater organic and ionic solutes on TCE dechlorination using polyelectrolyte-modified NZVIs is unexplored, but is required for an effective remediation design. This study evaluates the TCE dechlorination rate and reaction by-products using poly(aspartate) (PAP)-modified and bare NZVIs in groundwater samples from actual TCE-contaminated sites in Florida, South Carolina, and Michigan. The effects of groundwater solutes on short- and intermediate-term dechlorination rates were evaluated. An adsorbed PAP layer on the NZVIs appeared to limit the adverse effect of groundwater solutes on the TCE dechlorination rate in the first TCE dechlorination cycle (short-term effect). Presumably, the pre-adsorption of PAP "trains" and the Donnan potential in the adsorbed PAP layer prevented groundwater solutes from further blocking NZVI reactive sites, which appeared to substantially decrease the TCE dechlorination rate of bare NZVIs. In the second and third TCE dechlorination cycles (intermediate-term effect), TCE dechlorination rates using PAP-modified NZVIs increased substantially (~100 and 200%, respectively, from the rate of the first spike). The desorption of PAP from the surface of NZVIs over time due to salt-induced desorption is hypothesized to restore NZVI reactivity with TCE. This study suggests that NZVI surface modification with small, charged macromolecules, such as PAP, helps to restore NZVI reactivity due to gradual PAP desorption in groundwater.

  7. Persistence of two neonicotinoid insecticides in wastewater, and in aqueous solutions of surfactants and dissolved organic matter.

    Science.gov (United States)

    Peña, A; Rodríguez-Liébana, J A; Mingorance, M D

    2011-07-01

    Wastewater treatment plants receive organic contaminants, such as pesticides, which reach the sewage system from domestic, industrial or agricultural activities. In wastewater, which is a complex mixture of organic and inorganic compounds, biotic or abiotic degradation of contaminants can be affected by the presence of co-solutes. The photodecomposition in natural sunlight of two neonicotinoid insecticides, thiamethoxam and thiacloprid, was investigated in wastewater, aqueous extracts of sewage sludge and in aqueous surfactant solutions, which are abundant in wastewater. Dissipation in the dark was also studied in wastewater, due to reduction of transmitted sunlight in wastewater ponds. With regard to photolysis, thiamethoxam degraded rapidly in all the aqueous solutions. Among them sewage sludge extracts slightly modified (average half-life 17.6h), wastewater increased (13.7h) and non-ionic surfactants led, as a family, to the highest dissipation rates (average 6.2h), with respect to control water (18.7h). Additionally this pesticide also underwent a slower biodegradation process in wastewater in the dark under anaerobic conditions (around 25d). A metabolite of thiamethoxam from the biological decomposition in wastewater was identified by HPLC/MS. On the other hand thiacloprid was found to be resistant to photo- and biodecomposition and remained almost unchanged during the experimental periods in all the tested media.

  8. Thermoelastic analysis of spent fuel and high level radioactive waste repositories in salt. A semi-analytical solution. [JUDITH

    Energy Technology Data Exchange (ETDEWEB)

    St. John, C.M.

    1977-04-01

    An underground repository containing heat generating, High Level Waste or Spent Unreprocessed Fuel may be approximated as a finite number of heat sources distributed across the plane of the repository. The resulting temperature, displacement and stress changes may be calculated using analytical solutions, providing linear thermoelasticity is assumed. This report documents a computer program based on this approach and gives results that form the basis for a comparison between the effects of disposing of High Level Waste and Spent Unreprocessed Fuel.

  9. Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Po-Neng [Experimental Forest, National Taiwan University, Chushan, Nantou County, 55750, Taiwan (China); Tong, Ou-Yang [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Chiou, Chyow-San; Lin, Yu-An [Department of Environmental Engineering, National Ilan University, Ilan 26047, Taiwan (China); Wang, Ming-Kuang [Department of Animal Science, National Ilan University, Ilan 26047, Taiwan (China); Liu, Cheng-Chung, E-mail: ccliu@niu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan (China)

    2016-01-15

    Highlights: • Nitrogen, phosphorus, and potassium contents in soil are substantially increased after the DOC washing. • The removal of Zn is dominated by proton replacement at pH 2.0, rather than by complexation with DOC. • The removal of Zn is dominated by DOC complexation between pH 3.0 and pH 5.0. - Abstract: A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg{sup −1} in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L{sup −1} DOC solution with a of pH 2.0 at 25 °C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH{sub 4}{sup +}-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

  10. Dissolved oxygen

    National Research Council Canada - National Science Library

    1981-01-01

    Dissolved oxygen concentrations in the waters of Botany Bay and Georges and Cooks Rivers vary mainly as a result of tidal water movements, algal and macrophytic growth and decay, and effects of storms...

  11. Americium/Lanthanide Separations in Alkaline Solutions for Advanced Nuclear Fuel Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Goff, George S. [Los Alamos National Laboratory; Long, Kristy Marie [Los Alamos National Laboratory; Reilly, Sean D. [Los Alamos National Laboratory; Jarvinen, Gordon D. [Los Alamos National Laboratory; Runde, Wolfgang H. [Los Alamos National Laboratory

    2012-06-11

    Project goals: Can used nuclear fuel be partitioned by dissolution in alkaline aqueous solution to give a solution of uranium, neptunium, plutonium, americium and curium and a filterable solid containing nearly all of the lanthanide fission products and certain other fission products? What is the chemistry of Am/Cm/Ln in oxidative carbonate solutions? Can higher oxidation states of Am be stabilized and exploited? Conclusions: Am(VI) is kinetically stable in 0.5-2.0 M carbonate solutions for hours. Aliquat 336 in toluene has been successfully shown to extract U(VI) and Pu(VI) from carbonate solutions. (Stepanov et al 2011). Higher carbonate concentration gives lower D, SF{sub U/Eu} for = 4 in 1 M K{sub 2}CO{sub 3}. Experiments with Am(VI) were unsuccessful due to reduction by the organics. Multiple sources of reducing organics...more optimization. Reduction experiments of Am(VI) in dodecane/octanol/Aliquat 336 show that after 5 minutes of contact, only 30-40% of the Am(VI) has been reduced. Long enough to perform an extraction. Shorter contact times, lower T, and lower Aliquat 336 concentration still did not result in any significant extraction of Am. Anion exchange experiments using a strong base anion exchanger show uptake of U(VI) with minimal uptake of Nd(III). Experiments with Am(VI) indicate Am sorption with a Kd of 9 (10 minute contact) but sorption mechanism is not yet understood. SF{sub U/Nd} for = 7 and SF{sub U/Eu} for = 19 after 24 hours in 1 M K{sub 2}CO{sub 3}.

  12. Strategic network design of Java Island fuel supply with production-transportation solution

    Science.gov (United States)

    Dianawati, Fauzia; Farizal, -; Surjandari, Isti; Marzuli, Rully

    2011-10-01

    This study aims to find more efficient supply network, from refineries / imports to fuel terminal, which still uses the Tanker, Tank Trucks or Rail Tank Wagon with an alternative pipeline that are considered more efficient than other transport modes, as well as gaining pipeline transportation network optimization analysis tailored to the capabilities/ capacity of refinery production and capacity of the pipe mode. With the complexity of the number of 3 point sources of supply, 19 destination of terminal, 4 kinds of products and 4 types of transport modes, transport-production model modified by adding multi-modal transport and investment costs of new pipeline. Then coded in Lingo program which adopts Branch & Bound technique and input the processed data in order to obtain an optimal distribution pattern produced the lowest distribution costs. This B&B solution was also compared with SCO solution which is a metaheuristic method. The results of this study lead to the development of new modes of pipeline connections in amount of 4 alternatives, generated from the optimal solution, but still potentially earned savings of about IDR 1 Trillion per year from cost-efficiency of product procurement and transportation costs.

  13. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    Directory of Open Access Journals (Sweden)

    D. van Pinxteren

    2015-09-01

    Full Text Available Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010 cloud experiment. Besides bulk collectors, a 3-stage and a 5-stage collector were applied and samples were analysed for inorganic ions (SO42−, NO3−, NH4+, Cl−, Na+, Mg2+, Ca2+, K+, H2O2 (aq, S(IV, and dissolved organic carbon (DOC. Campaign volume-weighted mean concentrations were 191, 142, and 39 μmol L−1 for ammonium, nitrate, and sulfate, respectively, between 4 and 27 μmol L−1 for minor ions, 5.4 μmol L−1 for H2O2 (aq, 1.9 μmol L−1 for S(IV, and 3.9 mgC L−1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC · 1.8 contributed 20–40 % (event means to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60–66 % for solute concentrations and 52–80 % for cloud water loadings (CWLs. Contrary to some earlier suggestions, the similar variability of solute concentrations and CWLs together with the results of back trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history, rather than cloud liquid water content (LWC was the main factor controlling bulk solute concentrations at Mt. Schmücke. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CV and analysed by an aerosol mass spectrometer (AMS, with

  14. DISSOLUTION OF IRRADIATED MURR FUEL ASSEMBLIES EFFECT OF INCREASED PURGE RATE AND CATALYST CONCENTRATION ON THE BATCH SIZE

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.

    2010-07-22

    Flowsheets for the dissolution of aluminum-clad spent nuclear fuel have been proposed using 0.002 M mercuric nitrate catalyst in 5 to 6 M nitric acid. Previous calculations for flammable gas control during the dissolution of spent nuclear fuel have been extended to cover a range of dissolver purge rates from 40 to 55 scfm. A range of dissolver solution volumes from 12000 to 15000 liters were considered for the large H-Canyon dissolver (6.4D). Depending on the purge rate, anywhere from four to six bundles of MURR fuel can be initially charged to the dissolver (6.4D). For successive charges where the dissolver solution already contains 0.002 M mercury catalyst and the dissolved aluminum from five bundles of MURR fuel, five to nine bundles of additional fuel can be charged depending on the purge rate and the dissolver solution volume. Similar calculations have been performed for the small H-Canyon dissolver (6.1D) for solution volumes that ranged from 6000 to 7500 liters and purge rates from 40 to 55 scfm. The limitations on the initial charge are four to six bundles depending on the purge rate. The aluminum from four bundles of fuel in an initial charge will allow nine to ten bundles in the second charge to 6.1D depending on the purge rate and dissolver solution volume. Solubility or criticality limitations will restrict the second charge on the small dissolver. The concentration of aluminum from previous charges will slow the dissolution rate to extend the cycle time of repeated charges of fuel. Calculations have been performed to allow a second catalyst addition (up to 0.004 M total catalyst) to reduce the cycle time (as necessary) based on the aluminum concentration and the purge rate.

  15. Investigating the Temporal Effects of Metal-Based Coagulants to Remove Mercury from Solution in the Presence of Dissolved Organic Matter

    Science.gov (United States)

    Henneberry, Yumiko; Kraus, Tamara E. C.; Krabbenhoft, David P.; Horwath, William R.

    2016-01-01

    The presence of mercury (Hg), particularly methylmercury (MeHg), is a concern for both human and ecological health as MeHg is a neurotoxin and can bioaccumulate to lethal levels in upper trophic level organisms. Recent research has demonstrated that coagulation with metal-based salts can effectively remove both inorganic mercury (IHg) and MeHg from solution through association with dissolved organic matter (DOM) and subsequent flocculation and precipitation. In this study, we sought to further examine interactions between Hg and DOM and the resulting organo-metallic precipitate (floc) to assess if (1) newly added IHg could be removed to the same extent as ambient IHg or whether the association between IHg and DOM requires time, and (2) once formed, if the floc has the capacity to remove additional Hg from solution. Agricultural drainage water samples containing ambient concentrations of both DOM and IHg were spiked with a traceable amount of isotopically enriched IHg and dosed with ferric sulfate after 0, 1, 5, and 30 days. Both ambient and newly added IHg were removed within hours, with 69-79 % removed. To a separate sample set, isotopically enriched IHg was added to solution after floc had formed. Under those conditions, 81-95 % of newly added Hg was removed even at Hg concentrations 1000-fold higher than ambient levels. Results of this study indicate coagulation with ferric sulfate effectively removes both ambient and newly added IHg entering a system and suggests rapid association between IHg and DOM. This work also provides new information regarding the ability of floc to remove additional Hg from solution even after it has formed.

  16. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...

  17. Role of Chloride Ion and Dissolved Oxygen in Electrochemical Corrosion of AA5083-H321 Aluminum-Magnesium Alloy in NaCl Solutions under Flow Conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Flow-induced corrosion consists electrochemical and mechanical components. The present paper has to assessed the role of chloride ion and dissolved oxygen in the electrochemical component of flow induced corrosion for AA5083-H321 aluminum-magnesium alloy which is extensively used in the construction of high-speed boats, submarines, hovercrafts, and desalination systems, in NaCl solutions. Electrochemical tests were carried out at flow velocities of 0, 2, 5, 7 and 10 m/s, in aerated and deaerated NaCl solutions with different sodium chloride concentrations. The results showed that the high rate of oxygen reduction under hydrodynamic conditions causes an increase in the density of pits on the surface. The increase of chloride ions concentration under flow conditions accelerates the rate of anodic reactions, but have no influence on the cathodic reactions. Thus, in the current work, it was found that under flow conditions, due to the elimination of corrosion products inside the pits, corrosion resistance of the alloy is increased.

  18. Distributions of 14 elements into 10 liquid extractants from simulated acid-dissolved sludge and acidified supernate solutions of Hanford high-level waste

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F. [Sandia National Labs., Albuquerque, NM (United States); Svitra, Z.V.; Bowen, S.M. [Los Alamos National Lab., NM (United States)

    1994-02-01

    The distributions of 14 elements into ten extractants were measured from simulant solutions that represent acidic dissolved sludge and acidified supernate from Hanford HLW Tank 102-SY. The extractants: LIX{sup TM}-26, LIX{sup TM}-54, LIX{sup TM}-84, LIX{sup TM}-1010, Cyanex{sup TM} 272, Cyanex{sup TM} 923, Aliquat{sup TM} 336, DHDECMP, DHDECMP-DIPB, and CMPO-DIPB, were sorbed on porous carbon beads to provide dry-appearing beads that would be suitable for column operations. The selected elements, which represent fission products: Ce, Cs, Sr, Tc, and Y; actinides: U, Pu, and Am; and matrix elements: Cr, Co, Fe, Mn, Zn, and Zr; were traced by radionuclides and measured by gamma spectrometry. Distribution coefficients for each of 280 element/absorber/solution combinations were measured for dynamic contact periods of 30 minutes, 2 hours, and 6 hours to provide sorption kinetics information for the selected elements from these complex media. The resulting 840 measured distribution coefficients are presented.

  19. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    Science.gov (United States)

    van Pinxteren, Dominik; Wadinga Fomba, Khanneh; Mertes, Stephan; Müller, Konrad; Spindler, Gerald; Schneider, Johannes; Lee, Taehyoung; Collett, Jeffrey L.; Herrmann, Hartmut

    2016-03-01

    Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a three-stage and a five-stage collector were applied and samples were analysed for inorganic ions (SO42-,NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 µmol L-1 for ammonium, nitrate, and sulfate respectively, between 4 and 27 µmol L-1 for minor ions, 5.4 µmol L-1 for H2O2 (aq), 1.9 µmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC × 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). The similar variability of solute concentrations and CWLs together with the results of back-trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC), were the main factor controlling bulk solute concentrations for the cloud studied. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CVI) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic

  20. Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis.

    Science.gov (United States)

    Palomares, R I; Dayman, K J; Landsberger, S; Biegalski, S R; Soderquist, C Z; Casella, A J; Brady Raap, M C; Schwantes, J M

    2015-04-01

    Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared.

  1. Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain,Northeast China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Overwhelming evidence reveals that concentrations of dissolved organic carbon (DOC) have increased in streams which brings negative environmental impacts.DOC in stream flow is mainly originated from soil-water solutions of watershed.Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems.This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland,i.e.,a dishing wetland and a forest wetland together,in the Sanjiang Plain.Northeast China.The results indicate that DOC concentrations in soil-water solutions decreased and then increased with increasing soil depth in the annular wetland.In the upper soil layers of 0-10 cm and 10-20 cm,DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland (R2=0.3122 and R2=0.443).The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions.The concentrations of total organic carbon (TOC),total carbon (TC) and Fe(Ⅱ),DOC mobility and continuous vertical and lateral flow affected the distribution variations of DOC in soil-water solutious.The correlation coefficients between DOC concentrations and TOC,TC and Fe(Ⅱ) were 0.974,0.813 and 0.753 respectively.These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments.However,the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale.These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports,which would bring negative environmental impacts in watersheds of the Sanjiang Plain.

  2. [Influence of buffer solutions on the performance of microbial fuel cell electricity generation].

    Science.gov (United States)

    Qiang, Lin; Yuan, Lin-jiang; Ding, Qing

    2011-05-01

    Microbial fuel cell (MFC) is a potential green technology due to its application in wastewater treatment and renewable energy generation. Phosphate buffer solution (PBS) has been commonly used in MFC studies to maintain a suitable pH for electricity generating bacteria and/or to increase the solution conductivity. However, it has some drawbacks using PBS in MFC: One is that the addition of a high concentration of phosphate buffer in MFCs is expensive, especially for the application in wastewater treatment; the other is that phosphates can contribute to the eutrophication conditions of water bodies if the effluents are discharged without the removal of phosphates. By adding PBS buffer as the comparison, the study investigated the effect of borax buffer and in the absence of buffer on the performance of electrical power, coulomb efficiency and effluent pH. 200 mmol/L PBS was the best, conductivity was 1.973 mS/cm,the maximum power density was 36.4 mW/m2 and the maximum coulomb efficiency was 2.92%, effluent pH was almost at (7.00 +/- 0.05). 100 mmol/L borax buffer solution, conductivity was 1.553 mS/cm; the maximum power density was 26.2 mW/m2 coulomb efficiency of 6.26%, which was 2.14 times to PBS and greatly increased the electron recovery efficiency with the effluent pH was (7.35 +/- 0.05). While free buffer solution conductivity was 0.314 mS/cm, maximum power density was 27.64 mW/m2; coulomb efficiency was 2.82% and the effluent pH of approximately 7.43. The electrolyte which in absence of buffer solution conductivity was 1/6 of adding PBS buffer, 1/5 of borax buffer, while its power density lower 8.76 mW/mr2 than adding PBS and higher 1.24 mW/m2 than borax buffer. The results showed that adding the suitable concentration of borax buffer may improve the electron recovery efficiency and under batch conditions, MFC run successfully without adding buffer solution to MFC.

  3. Concentration-discharge relationships during an extreme event: Contrasting behavior of solutes and changes to chemical quality of dissolved organic material in the Boulder Creek Watershed during the September 2013 flood: SOLUTE FLUX IN A FLOOD EVENT

    Energy Technology Data Exchange (ETDEWEB)

    Rue, Garrett P. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Rock, Nathan D. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Gabor, Rachel S. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Pitlick, John [Department of Geography, University of Colorado, Boulder Colorado USA; Tfaily, Malak [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; McKnight, Diane M. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA

    2017-07-01

    During the week of September 10-17, 2013, close to 20 inches of rain fell across Boulder County, Colorado, USA. This rainfall represented a 1000-year event that caused massive hillslope erosion, landslides, and mobilization of sediments. The resultant stream flows corresponded to a 100-year flood. For the Boulder Creek Critical Zone Observatory (BC-CZO), this event provided an opportunity to study the effect of extreme rainfall on solute concentration-discharge relationships and biogeochemical catchment processes. We observed base cation and dissolved organic carbon (DOC) concentrations at two sites on Boulder Creek following the recession of peak flow. We also isolated three distinct fractions of dissolved organic matter (DOM) for chemical characterization. At the upper site, which represented the forested mountain catchment, the concentrations of the base cations Ca, Mg and Na were greatest at the peak flood and decreased only slightly, in contrast with DOC and K concentrations, which decreased substantially. At the lower site within urban corridor, all solutes decreased abruptly after the first week of flow recession, with base cation concentrations stabilizing while DOC and K continued to decrease. Additionally, we found significant spatiotemporal trends in the chemical quality of organic matter exported during the flood recession, as measured by fluorescence, 13C-NMR spectroscopy, and FTICR-MS. Similar to the effect of extreme rainfall events in driving landslides and mobilizing sediments, our findings suggest that such events mobilize solutes by the flushing of the deeper layers of the critical zone, and that this flushing regulates terrestrial-aquatic biogeochemical linkages during the flow recession.

  4. Structural evolution of aqueous NaCl solutions dissolved in supercritical carbon dioxide under isobaric heating by mid and near infrared spectroscopy.

    Science.gov (United States)

    Oparin, R; Tassaing, T; Danten, Y; Besnard, M

    2005-03-01

    The local order in aqueous NaCl solutions diluted in supercritical carbon dioxide at constant pressure as a function of NaCl concentration and temperature has been investigated using near and mid infrared absorption spectroscopy. The near IR results have allowed us to estimate the water concentration in CO(2) rich phase, whereas the state of water aggregation in CO(2) phase was investigated using mid IR spectroscopy. The analysis of the band shape variations of the OD stretching mode of HOD led us to conclude that below 100 degrees C, water molecules dissolved in CO(2) exist only under their monomeric form, whatever the salt concentration is, whereas hydrogen-bonded species, namely, dimers start to appear at higher temperatures. Larger aggregates have a negligible concentration in the range of temperature-pressure investigated. Using near and mid infrared data, we have calculated the concentrations of water species in the CO(2) phase. Upon heating, it was found that the concentration of dimers considerably increases at the expense of the monomers and only dimers are detected in carbon dioxide at highest temperatures. Changing the salt concentration affects significantly the concentration of monomers and decreases strongly the dimers population as the solution becomes progressively saturated in salt. In the saturated solution, at 340 degrees C, the dimer concentration is at least two times smaller than in the binary water-CO(2) mixture. These findings are in qualitative agreement with existing thermodynamics data showing that addition of NaCl to the binary H(2)O-CO(2) system shifts the range of partial miscibility of water and CO(2) towards higher pressure and temperature.

  5. Instant release fraction and matrix release of high burn-up UO2 spent nuclear fuel: Effect of high burn-up structure and leaching solution composition

    Science.gov (United States)

    Serrano-Purroy, D.; Clarens, F.; González-Robles, E.; Glatz, J. P.; Wegen, D. H.; de Pablo, J.; Casas, I.; Giménez, J.; Martínez-Esparza, A.

    2012-08-01

    Two weak points in Performance Assessment (PA) exercises regarding the alteration of Spent Nuclear Fuel (SNF) are the contribution of the so-called Instant Release Fraction (IRF) and the effect of High Burn-Up Structure (HBS). This manuscript focuses on the effect of HBS in matrix (long term) and instant release of a Pressurised Water Reactor (PWR) SNF irradiated in a commercial reactor with a mean Burn-Up (BU) of 60 GWd/tU. In order to study the HBS contribution, two samples from different radial positions have been prepared. One from the centre of the SNF, labelled CORE, and one from the periphery, enriched with HBS and labelled OUT. Static leaching experiments have been carried out with two synthetic leaching solutions: bicarbonate (BIC) and Bentonitic Granitic Groundwater (BGW), and in all cases under oxidising conditions. IRF values have been calculated from the determined Fraction of Inventory in Aqueous Phase (FIAP). In all studied cases, some radionuclides (RN): Rb, Sr and Cs, have shown higher release rates than uranium, especially at the beginning of the experiment, and have been considered as IRF. Redox sensitive RN like Mo and Tc have been found to dissolve slightly faster than uranium and further studies might be needed to confirm if they can also be considered part of the IRF. Most of the remaining studied RN, mainly actinides and lanthanides, have been found to dissolve congruently with the uranium matrix. Finally, Zr, Ru and Rh presented lower release rates than the matrix. Higher matrix release has been determined for CORE than for OUT samples showing that the formation of HBS might have a protective effect against the oxidative corrosion of the SNF. On the contrary, no significant differences have been observed between the two studied leaching solutions (BIC and BGW). Two different IRF contributions have been determined. One corresponding to the fraction of inventory segregated in the external open grain boundaries, directly available to water and

  6. Parameterizing the binding properties of dissolved organic matter with default values skews the prediction of copper solution speciation and ecotoxicity in soil.

    Science.gov (United States)

    Djae, Tanalou; Bravin, Matthieu N; Garnier, Cédric; Doelsch, Emmanuel

    2017-04-01

    Parameterizing speciation models by setting the percentage of dissolved organic matter (DOM) that is reactive (% r-DOM) toward metal cations at a single 65% default value is very common in predictive ecotoxicology. The authors tested this practice by comparing the free copper activity (pCu(2+)  = -log10 [Cu(2+) ]) measured in 55 soil sample solutions with pCu(2+) predicted with the Windermere humic aqueous model (WHAM) parameterized by default. Predictions of Cu toxicity to soil organisms based on measured or predicted pCu(2+) were also compared. Default WHAM parameterization substantially skewed the prediction of measured pCu(2+) by up to 2.7 pCu(2+) units (root mean square residual = 0.75-1.3) and subsequently the prediction of Cu toxicity for microbial functions, invertebrates, and plants by up to 36%, 45%, and 59% (root mean square residuals ≤9 %, 11%, and 17%), respectively. Reparametrizing WHAM by optimizing the 2 DOM binding properties (i.e., % r-DOM and the Cu complexation constant) within a physically realistic value range much improved the prediction of measured pCu(2+) (root mean square residual = 0.14-0.25). Accordingly, this WHAM parameterization successfully predicted Cu toxicity for microbial functions, invertebrates, and plants (root mean square residual ≤3.4%, 4.4%, and 5.8%, respectively). Thus, it is essential to account for the real heterogeneity in DOM binding properties for relatively accurate prediction of Cu speciation in soil solution and Cu toxic effects on soil organisms. Environ Toxicol Chem 2017;36:898-905. © 2016 SETAC. © 2016 SETAC.

  7. The oxidation and hydriding of zircaloy fuel cladding in high temperature aqueous solutions

    Science.gov (United States)

    Chen, Yingzi

    Nearly 90% of today's fission reactors use Zr based fuel cladding materials. The Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs) are the two most common water-cooled nuclear reactors. Corrosion is the principal threat to the failure of the fuel in these reactors, resulting in the release of fission products to the coolant and hence to the establishment of radiation fields in out-of-core regions of the coolant circuit (e.g., steam generators in PWRs and turbines in BWRs). As is well known, corrosion is an electrochemical phenomenon; however, electrochemical effects are often neglected in corrosion studies on zirconium and its alloys, because of the difficulty in performing well-defined experiments under the appropriate conditions (high temperatures and pressures). In-situ studies have been carried out to examine the electrochemistry of passive zirconium under simulated BWR and PWR coolant conditions by using a controlled hydrodynamic, high temperature/high pressure test cell. The oxidation/hydriding mechanisms are elucidated by measuring the current, impedance, and capacitance of passive zirconium as a function of formation potential. The data are interpreted in terms of a modified point defect model (PDM) that recognize the existence of a passive film comprising a thick oxide outer layer over a thin barrier layer. From the composition of the zirconium passive film and thermodynamic analysis, it is postulated that a hydride barrier layer forms under PWR coolant conditions whereas an oxide barrier layer forms under BWR primary coolant conditions. Transients in current density and the thickness of the passive film formed on zirconium, when stepping the potential in either the positive or negative directions, have confirmed that the rate law afforded by the PDM adequately describes the growth and thinning of the passive film at high temperatures. The experimental results demonstrate that the kinetics of either oxygen or hydrogen vacancy generation

  8. Analysis of Criticality Accident Transients of Uranium Solution System

    Institute of Scientific and Technical Information of China (English)

    DUAN; Ming-hui; DU; Kai-wen; LIU; Zhen-hua

    2012-01-01

    <正>In the nuclear fuel cycle, fissile materials are often dissolved in water. Criticality accidents are likely to happen in the uranium solution system and release a large amount of energy and radioactive materials. Therefore, the criticality safety of uranium solution system is very important in the nuclear safety technology research.

  9. A Parallel Multi-Domain Solution Methodology Applied to Nonlinear Thermal Transport Problems in Nuclear Fuel Pins

    CERN Document Server

    Philip, Bobby; Allu, Srikanth; Hamilton, Steven P; Sampath, Rahul S; Clarno, Kevin T; Dilts, Gary A

    2014-01-01

    This paper describes an efficient and nonlinearly consistent parallel solution methodology for solving coupled nonlinear thermal transport problems that occur in nuclear reactor applications over hundreds of individual 3D physical subdomains. Efficiency is obtained by leveraging knowledge of the physical domains, the physics on individual domains, and the couplings between them for preconditioning within a Jacobian Free Newton Krylov method. Details of the computational infrastructure that enabled this work, namely the open source Advanced Multi-Physics (AMP) package developed by the authors is described. Details of verification and validation experiments, and parallel performance analysis in weak and strong scaling studies demonstrating the achieved efficiency of the algorithm are presented. Furthermore, numerical experiments demonstrate that the preconditioner developed is independent of the number of fuel subdomains in a fuel rod, which is particularly important when simulating different types of fuel rods...

  10. Supply Chain Based Solution to Prevent Fuel Tax Evasion: Proof of Concept Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Capps, Gary J [ORNL; Lascurain, Mary Beth [ORNL; Franzese, Oscar [ORNL; Earl, Dennis Duncan [ORNL; West, David L [ORNL; McIntyre, Timothy J [ORNL; Chin, Shih-Miao [ORNL; Hwang, Ho-Ling [ORNL; Connatser, Raynella M [ORNL; Lewis Sr, Samuel Arthur [ORNL; Moore, Sheila A [ORNL

    2011-12-01

    The goal of this research was to provide a proof-of-concept (POC) system for preventing non-taxable (non-highway diesel use) or low-taxable (jet fuel) petrochemical products from being blended with taxable fuel products and preventing taxable fuel products from cross-jurisdiction evasion. The research worked to fill the need to validate the legitimacy of individual loads, offloads, and movements by integrating and validating, on a near-real-time basis, information from global positioning system (GPS), valve sensors, level sensors, and fuel-marker sensors.

  11. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...... leachates showed different Cd speciation patterns as expected. Some leachates were dominated by free divalent Cd (1-70%), some by inorganic complexes (1-87%), and some by organic complexes (7-98%)....

  12. Oxidizing dissolution of spent MOX47 fuel subjected to water radiolysis: Solution chemistry and surface characterization by Raman spectroscopy

    Science.gov (United States)

    Jégou, C.; Caraballo, R.; De Bonfils, J.; Broudic, V.; Peuget, S.; Vercouter, T.; Roudil, D.

    2010-04-01

    The mechanisms of oxidizing dissolution of spent MOX fuel (MIMAS TU2®) subjected to water radiolysis were investigated experimentally by leaching spent MOX47 fuel samples in pure water at 25 °C under different oxidizing conditions (with and without external gamma irradiation); the leached surfaces were characterized by Raman spectroscopy. The highly oxidizing conditions resulting from external gamma irradiation significantly increased the concentration of plutonium (Pu(V)) and uranium (U(VI)) compared with a benchmark experiment (without external irradiation). The oxidation behavior of the plutonium-enriched aggregates differed significantly from that of the UO 2 matrix after several months of leaching in water under gamma irradiation. The plutonium in the aggregates appears to limit fuel oxidation. The only secondary phases formed and identified to date by Raman spectroscopy are uranium peroxides that generally precipitate on the surface of the UO 2 grains. Concerning the behavior of plutonium, solution analysis results appear to be compatible with a conventional explanation based on an equilibrium with a Pu(OH) 4(am) phase. The fission product release - considered as a general indicator of matrix alteration - from MOX47 fuel also increases under external gamma irradiation and a change in the leaching mode is observed. Diffusive leaching was clearly identified, coinciding with the rapid onset of steady-state actinide concentrations in the bulk solution.

  13. Corrosion of non-irradiated UAl{sub x}-Al fuel in the presence of clay pore solution. A quantitative XRD secondary phase analysis applying the DDM method

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Andreas [Halle-Wittenberg Univ. (Germany). Dept. of Mineralogy and Geochemistry; RWTH Aachen Univ. (Germany). Inst. of Crystallography; Klinkenberg, Martina; Curtius, Hildegard [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research, IEK-6 Nuclear Waste Management

    2017-04-01

    Corrosion experiments with non-irradiated metallic UAl{sub x}-Al research reactor fuel elements were carried out in autoclaves to identify and quantify the corrosion products. Such compounds, considering the long-term safety assessment of final repositories, can interact with the released inventory and this constitutes a sink for radionuclide migration in formation waters. Therefore, the metallic fuel sample was subjected to clay pore solution to investigate its process of disintegration by analyzing the resulting products and the remnants, i.e. the secondary phases. Due to the fast corrosion rate a full sample disintegration was observed within the experimental period of 1 year at 90 C. The obtained solids were subdivided into different grain size fractions and prepared for analysis. The elemental analysis of the suspension showed that, uranium and aluminum are concentrated in the solids, whereas iron was mainly dissolved. Non-ambient X-ray diffraction (XRD) combined with the derivative difference minimization (DDM) method was applied for the qualitative and quantitative phase analysis (QPA) of the secondary phases. Gypsum and hemihydrate (bassanite), residues of non-corroded nuclear fuel, hematite, and goethite were identified. The quantitative phase analysis showed that goethite is the major crystalline phase. The amorphous content exceeded 80 wt% and hosted the uranium. All other compounds were present to a minor content. The obtained results by XRD were well supported by complementary scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.

  14. A parallel multi-domain solution methodology applied to nonlinear thermal transport problems in nuclear fuel pins

    Science.gov (United States)

    Philip, Bobby; Berrill, Mark A.; Allu, Srikanth; Hamilton, Steven P.; Sampath, Rahul S.; Clarno, Kevin T.; Dilts, Gary A.

    2015-04-01

    This paper describes an efficient and nonlinearly consistent parallel solution methodology for solving coupled nonlinear thermal transport problems that occur in nuclear reactor applications over hundreds of individual 3D physical subdomains. Efficiency is obtained by leveraging knowledge of the physical domains, the physics on individual domains, and the couplings between them for preconditioning within a Jacobian Free Newton Krylov method. Details of the computational infrastructure that enabled this work, namely the open source Advanced Multi-Physics (AMP) package developed by the authors is described. Details of verification and validation experiments, and parallel performance analysis in weak and strong scaling studies demonstrating the achieved efficiency of the algorithm are presented. Furthermore, numerical experiments demonstrate that the preconditioner developed is independent of the number of fuel subdomains in a fuel rod, which is particularly important when simulating different types of fuel rods. Finally, we demonstrate the power of the coupling methodology by considering problems with couplings between surface and volume physics and coupling of nonlinear thermal transport in fuel rods to an external radiation transport code.

  15. Release of [sup 14]C from the gap and grain-boundary regions of used CANDU fuels to aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Stroes-Gascoyne, S.; Tait, J.C.; Porth, R.J.; McConnell, J.L.; Lincoln, W.J. (Whiteshell Lab., Pinawa, Manitoba (Canada). AECL Research)

    1994-01-01

    This study was undertaken as part of the Canadian Nuclear Fuel Waste Management Program (CNFWMP), to measure [sup 14]C inventories of used CANDU fuel. Other objectives were to measure the fraction of the total [sup 14]C inventory that would be instantly released to solution from used CANDU fuels upon sheath failure and to determine if the assumptions made in safety assessment calculations of used fuel waste disposal regarding instant release of [sup 14]C were correct. Results showed that the measured [sup 14]C inventories were a factor of 11.5 [+-] 3.9 lower than the estimated [sup 14]C inventory values used in safety assessment calculations. Measured instant release values for [sup 14]C ranged from 0.06 to 5.04% (of total [sup 14]C inventories) with an average of 2.7 [+-] 1.6%, indicating that instant release fractions for [sup 14]C used in safety assessment calculations (1.2--25%) were overestimated.

  16. The use of electro spray mass spectrometry for the determination of dissolved species application for determination of zirconium complexes in reprocessing spent fuel matrice; Electrospray/spectrometrie de masse, technique d'avenir pour l'etude des complexes. Applications aux systemes U(6)/Zr(4) dans les conditions simulees du procede Purex

    Energy Technology Data Exchange (ETDEWEB)

    Lamouroux, Ch.; Moulin, Ch. [CEA Saclay, Dept. des Procedes d' Enrichissement (DCC/DPE/SPCP), 91 - Gif-sur-Yvette (France); Blanc, P. [CEA Valrho, (DCC/DRRV/SEMP), 30 - Marcoule (France)

    2000-07-01

    Liquid-liquid extraction of Zirconium one of the most important fission products, was investigated by Electro-spray Mass Spectrometry (ESI/MS) in simulated nuclear reprocessing spent fuel process conditions. Zr{sup IV} can precipitate at the organic / water interface after its extraction by dibutyl-phosphoric acid (HDBP), the most common degradation product of tributylphosphate (TBP) under radiolysis. However, precipitation of ZrI{sup IV} is restricted and particularly dependent on the ratio 'r': (HDBP){sub tot}/(Zr{sup IV}]{sub tot}. The type and characterization of the precipitate is reported in different papers as Zr(NO{sub 3}){sub 2}(DBP){sub 2}. complex. However, some uncertainties exist about the composition and structures of the dissolved Zr species extracted. Techniques already used for such purposes are NMR (Nuclear Magnetic Resonance) and vibrational spectroscopy, but identification of the extracted metal complex structures is debatable. To obtain more definitive information, the use of ESI/MS could be a complementary tool for characterizing the extracted metal complexes. ESI allows ionization/desorption of non-volatile analytes into gas phase detected by mass spectrometry with high sensitivity, making it a complementary tool for examining the speciation of dissolved metal species. Extractions were carried out for the system (ZrI{sup IV} in HNO{sub 3} 3M)/(TBP/C{sub 12}H{sub 26} 30/70 spiked with HDBP) by varying the ratio r. ZrI{sup IV} extraction was confirmed by ICP-AES (Inductively Coupled plasma-Atomic Emission Spectroscopy) measurements on the aqueous phase, and dissolved metal complexes were identified by ESI/MS experiments on the organic phase. Different complexes could be detected with ESI used in positive and negative ion mode as a function of the extraction conditions such as the ratio r. Good agreement is observed between the variation in mass spectra and Zr behavior described for solutions. For a ratio 0dissolved Zr species

  17. Freely dissolved concentrations of anionic surfactants in seawater solutions: optimization of the non-depletive solid-phase microextraction method and application to linear alkylbenzene sulfonates.

    NARCIS (Netherlands)

    Rico Rico, A.; Droge, S.T.J.; Widmer, D.; Hermens, J.L.M.

    2009-01-01

    A solid-phase microextraction method (SPME) has been optimized for the analysis of freely dissolved anionic surfactants, namely linear alkylbenzene sulfonates (LAS), in seawater. An effect of the thermal conditioning treatment on the polyacrylate fiber coating was demonstrated for both uptake kineti

  18. Simultaneous pollutant removal and electricity generation in denitrifying microbial fuel cell with boric acid-borate buffer solution.

    Science.gov (United States)

    Chen, Gang; Zhang, Shaohui; Li, Meng; Wei, Yan

    2015-01-01

    A double-chamber denitrifying microbial fuel cell (MFC), using boric acid-borate buffer solution as an alternative to phosphate buffer solution, was set up to investigate the influence of buffer solution concentration, temperature and external resistance on electricity generation and pollutant removal efficiency. The result revealed that the denitrifying MFC with boric acid-borate buffer solution was successfully started up in 51 days, with a stable cell voltage of 205.1 ± 1.96 mV at an external resistance of 50 Ω. Higher concentration of buffer solution favored nitrogen removal and electricity generation. The maximum power density of 8.27 W/m(3) net cathodic chamber was obtained at a buffer solution concentration of 100 mmol/L. An increase in temperature benefitted electricity generation and nitrogen removal. A suitable temperature for this denitrifying MFC was suggested to be 25 °C. Decreasing the external resistance favored nitrogen removal and organic matter consumption by exoelectrogens.

  19. Bio-inspired solutions in design for manufacturing of micro fuel cell

    DEFF Research Database (Denmark)

    Omidvarnia, Farzaneh; Hansen, Hans Nørgaard

    2014-01-01

    In this paper the application of biomimetic principles in design for micro manufacturing is investigated. A micro direct methanol fuel cell (μDMFC) for power generation in hearing aid devices is considered as the case study in which the bioinspired functions are replicated. The focus in design of...

  20. Extremely thin bilayer electrolyte for solid oxide fuel cells (SOFCs) fabricated by chemical solution deposition (CSD).

    Science.gov (United States)

    Oh, Eun-Ok; Whang, Chin-Myung; Lee, Yu-Ri; Park, Sun-Young; Prasad, Dasari Hari; Yoon, Kyung Joong; Son, Ji-Won; Lee, Jong-Ho; Lee, Hae-Weon

    2012-07-03

    An extremely thin bilayer electrolyte consisting of yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) is successfully fabricated on a sintered NiO-YSZ substrate. Major processing flaws are effectively eliminated by applying local constraints to YSZ nanoparticles, and excellent open circuit voltage and cell performance are demonstrated in a solid oxide fuel cell (SOFC) at intermediate operating temperatures.

  1. On the Existence of a Weak Solution of a Half-Cell Model for PEM Fuel Cells

    Directory of Open Access Journals (Sweden)

    Shuh-Jye Chern

    2010-01-01

    Full Text Available A nonlinear boundary value problem (BVP from the modelling of the transport phenomena in the cathode catalyst layer of a one-dimensional half-cell single-phase model for proton exchange membrane (PEM fuel cells, derived from the 3D model of Zhou and Liu (2000, 2001, is studied. It is a BVP for a system of three coupled ordinary differential equations of second order. Schauder's fixed point theorem is applied to show the existence of a solution in the Sobolev space 1.

  2. Dissolver Off-gas Hot Operations Authorization (AFCI CETE Milestone Report)

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, Robert Thomas [ORNL

    2009-06-01

    The head-end processing of the Coupled-End-to-End (CETE) Demonstration includes fuel receipt, fuel disassembly, exposure of fuel (e.g., by segmenting the fuel pins), voloxidation of the fuel to separate tritium, and fuel dissolution. All of these processing steps with the exception of the dissolution step will be accomplished in the Irradiated Fuels Examination Laboratory (IFEL) (Building 3525). The final headend step will be performed in the Radiochemical Engineering Development Center (Building 7920). The primary purpose of the fuel dissolution step is to prepare the solid fuel for subsequent liquid separations steps. This is accomplished by dissolving the fuel solids using nitric acid. During the dissolution process gases are evolved. Oxides of nitrogen are the primary off-gas components generated by the reactions of nitric acid and the fuel oxides however, during the dissolution and sparging of the resulting solution, iodine, C-14 as carbon dioxide, xenon, and krypton gasses are also released to the off-gas stream. The Dissolver Off-gas treatment rack provides a means of trapping these volatile fission products and other gases via various trapping media. Specifically the rack will recover iodine on a solid sorbent bed, scrub NOx in a water/acid column, scrub CO{sub 2} in a caustic scrubber column, remove moisture with solid sorbent drier beds and recover Xe and Kr using solid absorbent beds. The primary purpose of this experimental rack and the off-gas rack associated with the voloxidation equipment located at IFEL is to close the material balances around the volatile gases and to provide an understanding of the impacts of specific processing conditions on the fractions of the volatile components released from the various head-end processing steps.

  3. 乏燃料后处理溶解过程核临界安全初步分析%Nuclear Criticality Safety Analysis in Dissolving Process of Spent Fuel Reprocessing

    Institute of Scientific and Technical Information of China (English)

    刘颖瑜; 骆志文; 刘振华

    2013-01-01

    A rational space distribution model for spent fuel element dissolving at each stage of process in reprocessing plant was formulated .The nuclear criticality on safety issue was studied by calculating numerical model on the process of spent fuel dissolution in consideration of the given plant arrangement . An assessment of the influence of several main critical parameters to the plant safety was given .The calculation results show that the most dangerous status occurs at the initial stage of dissolution w hen fissile nuclide transforms under ideal conditions . A negative influence to the system is indicated by the increase of temperature and concentration of nitric acid ,and the effect is less than 4% .System safety can be improved greatly by the addition of neutron poison or the application of fuel burnup credit ,and the effect reaches 30% .%通过建立合理的空间分布模型,对后处理厂乏燃料溶解不同阶段的核临界安全问题进行分析,同时对重要的核临界安全参数给予影响评价。结果显示,在仅考虑易裂变核素形态转变的理想情况下,溶解初期为最危险状态;温度升高和硝酸浓度增大对系统的影响为负效应,影响均小于4%;可溶中子毒物的加入与燃耗信任制技术的应用能大幅提高系统的经济性,影响均可达到30%。

  4. A study of solute transport of radiolysis products in crud and its effects on crud growth on PWR fuel pin

    Energy Technology Data Exchange (ETDEWEB)

    Joe, Justin H. [BNF Consulting (United States); Kim, Seung Jun, E-mail: skim@lanl.gov [Mechanical and Thermal Engineering Group (AET-1), Los Alamos National Laboratory (United States); Jones, Barclay G. [Department of Nuclear Plasma Radiological Engineering, University of Illinois Urbana-Champaign (United States)

    2016-04-15

    Highlights: • We model a 3-D numerical solute transport within crud deposit on PWR fuel pin. • Source term effect from radiolysis yield and recombination is minimal. • Lower crud porosity leads substantially higher concentration of solutes. • Thicker crud deposit generates substantially higher concentration of solutes. • High concentration of radiolysis species (H{sub 2}, O{sub 2}, and H{sub 2}O{sub 2}) can be directly related to corrosion issues on fuel cladding. - Abstract: This research examines the concentration of radiolysis species (H{sub 2}, O{sub 2}, and H{sub 2}O{sub 2}) over the porous crud layer using a three dimensional time dependent solute transport model. A Monte Carlo random walk technique is adopted to simulate the transport behavior of the different species with various parametric studies of source term, crud thickness, and crud porosity. Particularly, this model employs a system of coupled mass transport and chemical interactions as the source term, which makes the problem non-linear. It is demonstrated that a negligible effect on radiolysis species concentrations change due to the consideration of source term. The crud thickness and porosity effect on the concentration distributions are notably observed. In general, higher concentration starts from the intersection of the heating surface with the chimney wall from the beginning and it reaches the equilibrium state within tens of seconds. The concentration profiles of the radiolysis species H{sub 2}, O{sub 2}, and H{sub 2}O{sub 2} can be directly related to corrosion issues. The direct application of this study to nuclear engineering research is to aid in the design of reactors with higher performance without experiencing an Axial Offset Anomaly (AOA), an unexpected measured shift in axial power distribution from predicted values.

  5. Coal and wood fuel for electricity production: An environmentally sound solution for waste and demolition wood

    Energy Technology Data Exchange (ETDEWEB)

    Penninks, F.W.M. [EPON, Zwolle (Netherlands)

    1997-12-31

    Waste wood from primary wood processing and demolition presents both a problem and a potential. If disposed in landfills, it consumes large volumes and decays, producing CH{sub 4}, CO{sub 2} and other greenhouse gases. As an energy source used in a coal fired power plant it reduces the consumption of fossil fuels reducing the greenhouse effect significantly. Additional advantages are a reduction of the ash volume and the SO{sub 2} and NO{sub x} emissions. The waste wood requires collection, storage, processing and burning. This paper describes a unique project which is carried out in the Netherlands at EPON`s Gelderland Power Plant (635 MW{sub e}) where 60 000 tonnes of waste and demolition wood will be used annually. Special emphasis is given to the processing of the powdered wood fuel. Therefore, most waste and demolition wood can be converted from an environmental liability to an environmental and economic asset. (author)

  6. Numerical solution of moving boundary problem for deposition process in solid fuel gas generator

    Science.gov (United States)

    Volokhov, V. M.; Dorofeenko, S. O.; Sharov, M. S.; Toktaliev, P. D.

    2016-11-01

    Moving boundary problem in application to process of depositions formation in gas generator are considered. Gas generator, as a part of fuel preparation system of high-speed vehicle, convert solid fuel into multicomponent multiphase mixture, which further burned down in combustion chamber. Mathematical model of two-phase “gas-solid particles” flow, including Navier-Stokes equations for turbulent flow in gas generator and mass, impulse conservations laws for elementary depositions layer are proposed. Verification of proposed mathematical model for depositions mass in gas generator conditions is done. Further possible improvements of proposed model, based on more detail accounting of particle-wall interaction and wall's surface adhesion properties are analyzed.

  7. Analytical solutions of the mechanical behaviour of rock with applications to a repository for spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, P.

    1997-10-01

    Mechanical behaviour of rock is one of the main research areas of disposal of spent nuclear fuel. Various calculation programs designed to solve the problem are utilized by the planners of spent fuel disposal. The results of the numerical approaches can be validated by comparing them to the analytical solution of a simplified problem. As a basis for this study, we used Kirsch`s equations, which give the planar solution to the stress field developing around a horizontal tunnel of a circular cross section. Kirsch`s equations and the corresponding deformation (strain) and displacement fields were derived for a tunnel with and without a circular support. The rock mass was assumed to be a continuous, homogeneous and isotropic medium obeying Hooke`s law, and the time-dependent aspects of the fields were taken into account by applying the Poynting-Thomson model to the interaction between rock and a support. The Matlab code was used to calculate and visualize the results. As a result of this study, we state that the tangential, tensile stresses at the sides of the tunnel are of the same order of magnitude as the tensile strength of rock, which influences the fracturing. With a support, the effects can be moderately reduced. 7 refs.

  8. Recovery of minor actinides from irradiated superfact fuels

    Energy Technology Data Exchange (ETDEWEB)

    Apoltolidis, C.; Glatz, J.P.; Molinet, R.; Nicholl, A.; Pagliosa, G.; Romer, K.; Bokelund, H.; Koch, L. [European Commission, JRC, Institute fuer Transuranium Elements, Karlsruhe (Germany)

    1995-12-31

    It could be demonstrated that the reprocessing of fast reactor oxide fuels containing up to 45 % MA (Np and Am), irradiated in the PHENIX reactor in the frame of a transmutation study, is possible. The fuels were dissolved under PUREX type conditions in order to determine their behaviour in the head-end step of the reprocessing process. For one of the fuels containing 20 % Am and 20 % Np before irradiation, an almost complete partitioning of actinides from the dissolver solution could be achieved. Chromatographic extraction was used for the separation of the main bulk elements U, Pu and Np, whereas centrifugal extractors were used to separate the minor actinides from the remaining high level liquid wastes (HLLW). For the relevant radio-toxic isotopes a high recovery rate from the irradiation targets was reached. Those elements are thus available for new fuel fabrication. (authors) 12 refs.

  9. FY12 Final Report for PL10-Mod Separations-PD12: Electrochemically Modulated Separation of Plutonium from Dilute and Concentrated Dissolver Solutions for Analysis by Gamma Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Sandra H.; Arrigo, Leah M.; Duckworth, Douglas C.; Cloutier, Janet M.; Breshears, Andrew T.; Schwantes, Jon M.

    2013-05-01

    Accurate and timely analysis of plutonium in spent nuclear fuel is critical in nuclear safeguards for detection of both protracted and rapid plutonium diversions. Gamma spectroscopy is a viable method for accurate and timely measurements of plutonium provided that the plutonium is well separated from the interfering fission and activation products present in spent nuclear fuel. Electrochemically modulated separation (EMS) is a method that has been used successfully to isolate picogram amounts of Pu from nitric acid matrices. With EMS, Pu adsorption may be turned “on” and “off” depending on the applied voltage, allowing for collection and stripping of Pu without the addition of chemical reagents. In this work, we have scaled up the EMS process to isolate microgram quantities of Pu from matrices encountered in spent nuclear fuel during reprocessing. Several challenges have been addressed including surface area limitations, radiolysis effects, electrochemical cell performance stability, and chemical interferences. After these challenges were resolved, 6 µg Pu was deposited in the electrochemical cell with approximately an 800-fold reduction of fission and activation product levels from a spent nuclear fuel sample. Modeling showed that these levels of Pu collection and interference reduction may not be sufficient for Pu detection by gamma spectroscopy. The main remaining challenges are to achieve a more complete Pu isolation and to deposit larger quantities of Pu for successful gamma analysis of Pu. If gamma analyses of Pu are successful, EMS will allow for accurate and timely on-site analysis for enhanced Pu safeguards.

  10. A method to improve multiobjective genetic algorithm optimization of a self-fuel-providing LMFBR by niche induction among nondominated solutions

    Energy Technology Data Exchange (ETDEWEB)

    Toshinsky, Vladimir G.; Sekimoto, Hiroshi E-mail: hsekimot@nr.titech.ac.jp; Toshinsky, Georgy I

    2000-03-01

    A method to improve the optimization performance of a genetic algorithm (GA) for multiobjective optimization problems is proposed. It is based on niche induction among nondominated solutions that is fulfilled by the control on their reproduction potential by using a sharing function. It is applied to an equilibrium cycle fuel reloading pattern for a Self-Fuel-Providing Reactor, and it provides better results compared to ones obtained with an adaptation of a conventional method.

  11. Prediction of dissolved actinide concentrations in concentrated electrolyte solutions: a conceptual model and model results for the Waste Isolation Pilot Plant (WIPP)

    Energy Technology Data Exchange (ETDEWEB)

    Novak, C.F.; Moore, R.C. [Sandia National Labs., Albuquerque, NM (United States); Bynum, R.V. [Science Applications International Corp., Albuquerque, NM (United States)

    1996-10-25

    The conceptual model for WIPP dissolved concentrations is a description of the complex natural and artificial chemical conditions expected to influence dissolved actinide concentrations in the repository. By a set of physical and chemical assumptions regarding chemical kinetics, sorption substrates, and waste-brine interactions, the system was simplified to be amenable to mathematical description. The analysis indicated that an equilibrium thermodynamic model for describing actinide solubilities in brines would be tractable and scientifically supportable. This paper summarizes the conceptualization and modeling approach and the computational results as used in the WIPP application for certification of compliance with relevant regulations for nuclear waste repositories. The WIPP site contains complex natural brines ranging from sea water to 10x more concentrated than sea water. Data bases for predicting solubility of Am(III) (as well as Pu(III) and Nd(III)), Th(IV), and Np(V) in these brines under potential repository conditions have been developed, focusing on chemical interactions with Na, K, Mg, Cl, SO{sub 4}, and CO{sub 3} ions, and the organic acid anions acetate, citrate, EDTA, and oxalate. The laboratory and modeling effort augmented the Harvie et al. parameterization of the Pitzer activity coefficient model so that it could be applied to the actinides and oxidation states important to the WIPP system.

  12. Fabrication process for sintered mixed oxides soluble in nitric acid from nitrate solutions. [nuclear fuels]. Procede d'obtention d'oxydes mixtes frittes solubles dans l'acide nitrique a partir de solutions de nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R.; Germanaz, P.

    1987-10-02

    Mixed oxide nuclear fuels are obtained by mixing the nitrate solutions, concentration, heat treatment for an intermediary mixed oxide containing U(VI) and Pu(IV or VI), calcination to obtain U/sub 3/O/sub 8/, reduction in U(IV) and Pu(IV), pelletizing, sintering and machining. Less wastes are produced and the fuel pellets are soluble in nitric acid.

  13. Acidic surfactant solutions for tributylphosphate removal in nuclear fuel reprocessing plants: A formulation study

    Energy Technology Data Exchange (ETDEWEB)

    Causse, J.; Faure, S. [CEA Marcoule, LPAD, SPDE, DEN, 30 (France)

    2009-04-15

    The removal of tributylphosphate (TBP), an organic solvent widely used as a complexing agent for uranium and plutonium in nuclear plants, was investigated to understand and adapt the mechanisms involved in TBP detachment and solubilization in acidic surfactant solutions. Two well-known degreasing mechanisms, roll-up and emulsification, should be combined for maximum effect. These mechanisms were characterized with a CCD camera to measure contact angles between a solid substrate and a liquid drop. We measured the contact angles of a TBP drop deposited on a stainless steel plate immersed in an acidic surfactant solution, and quantified the amount of TBP solubilized in the micelles by turbidity measurements. Preliminary results of micelle size characterization by dynamic light scattering are presented. We formulated new acidic surfactant solutions associating two industrial surfactants, Pluronic P123 and Rewopal X1207L, with improvement factors in various fields (total organic matter content, oil detachment and solubilization efficiency, emulsion stability, etc.). (authors)

  14. Analytical solutions for the temperature field in a 2D incompressible inviscid flow through a channel with walls of solid fuel

    Directory of Open Access Journals (Sweden)

    Sorin BERBENTE

    2011-12-01

    Full Text Available A gas (oxidizer flows between two parallel walls of solid fuel. A combustion is initiated: the solid fuel is vaporized and a diffusive flame occurs. The hot combustion products are submitted both to thermal diffusion and convection. Analytical solutions can be obtained both for the velocity and temperature distributions by considering an equivalent mean temperature where the density and the thermal conductivity are evaluated. The main effects of heat transfer are due to heat convection at the flame. Because the detailed mechanism of the diffusion flame is not introduced the reference chemical reaction is the combustion of premixed fuel with oxidizer in excess. In exchange the analytical solution is used to define an ideal quasi-uniform combustion that could be realized by an n adequate control. The given analytical closed solutions prove themselves flexible enough to adjust the main data of some existing experiments and to suggest new approaches to the problem.

  15. Effect of growth solution, membrane size and array connection on microbial fuel cell power supply for medical devices.

    Science.gov (United States)

    Roxby, Daniel N; Nham Tran; Pak-Lam Yu; Nguyen, Hung T

    2016-08-01

    Implanted biomedical devices typically last a number of years before their batteries are depleted and a surgery is required to replace them. A Microbial Fuel Cell (MFC) is a device which by using bacteria, directly breaks down sugars to generate electricity. Conceptually there is potential to continually power implanted medical devices for the lifetime of a patient. To investigate the practical potential of this technology, H-Cell Dual Chamber MFCs were evaluated with two different growth solutions and measurements recorded for maximum power output both of individual MFCs and connected MFCs. Using Luria-Bertani media and connecting MFCs in a hybrid series and parallel arrangement with larger membrane sizes showed the highest power output and the greatest potential for replacing implanted batteries.

  16. Solar energised transport solution and customer preferences and opinions about alternative fuel Vehicles – the case of slovenia

    Directory of Open Access Journals (Sweden)

    Matjaž KNEZ

    2015-09-01

    Full Text Available Authorities in Slovenia and other EU member states are confronted with problems of city transportation. Fossil-fuel based transport poses two chief problems – local and global pollution, and dwindling supplies and ever increasing costs. An elegant solution is to gradually replace the present automobile fleet with low emission vehicles. This article first explores the economics and practical viability of the provision of solar electricity for the charging of electric vehicles by installation of economical available PV modules and secondly the customer preferences and opinions about alternative low emission vehicles. Present estimates indicate that for the prevailing solar climate of Celje – a medium-sized Slovenian town – the cost would be only 2.11€ cents/kWh of generated solar electricity. Other results have also revealed that the most relevant factor for purchasing low emission vehicle is total vehicle price.

  17. Criticality Safety Experimental Investigation of Heterogeneous Fuel

    Institute of Scientific and Technical Information of China (English)

    WANG; Fan; ZHOU; Qi; XIA; Zhao-dong; ZHU; Qing-fu

    2015-01-01

    The spent fuel dissolver is the most important component in the reprocessing plant of the spent fuel dissolver reprocessing steps.The tonnage throughput,criticality safety and economical efficiency of the reprocess or mostly depend on the tonnage throughput,treatment rate and criticality safety of the dissolver.Because of the

  18. Achieving a Green Solution: Limitations and Focus Points for Sustainable Algal Fuels

    Directory of Open Access Journals (Sweden)

    Blanca Antizar-Ladislao

    2012-05-01

    Full Text Available Research investigating the potential of producing biofuels from algae has been enjoying a recent revival due to heightened oil prices, uncertain fossil fuel sources and legislative targets aimed at reducing our contribution to climate change. If the concept is to become a reality however, many obstacles need to be overcome. Recent studies have suggested that open ponds provide the most sustainable means of cultivation infrastructure due to their low energy inputs compared to more energy intensive photobioreactors. Most studies have focused on strains of algae which are capable of yielding high oil concentrations combined with high productivity. Yet it is very difficult to cultivate such strains in open ponds as a result of microbial competition and limited radiation-use efficiency. To improve viability, the use of wastewater has been considered by many researchers as a potential source of nutrients with the added benefit of tertiary water treatment however productivity rates are affected and optimal conditions can be difficult to maintain year round. This paper investigates the process streams which are likely to provide the most viable methods of energy recovery from cultivating and processing algal biomass. The key findings are the importance of a flexible approach which depends upon location of the cultivation ponds and the industry targeted. Additionally this study recommends moving towards technologies producing higher energy recoveries such as pyrolysis or anaerobic digestion as opposed to other studies which focused upon biodiesel production.

  19. Dissolution of Irradiated Commercial UO2 Fuels in Ammonium Carbonate and Hydrogen Peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z.; Johnsen, Amanda M.; McNamara, Bruce K.; Hanson, Brady D.; Chenault, Jeffrey W.; Carson, Katharine J.; Peper, Shane M.

    2011-01-18

    We propose and test a disposition path for irradiated nuclear fuel using ammonium carbonate and hydrogen peroxide media. We demonstrate on a 13 g scale that >98% of the irradiated fuel dissolves. Subsequent expulsion of carbonate from the dissolver solution precipitates >95% of the plutonium, americium, curium, and substantial amounts of fission products, effectively partitioning the fuel at the dissolution step. Uranium can be easily recovered from solution by any of several means, such as ion exchange, solvent extraction, or direct precipitation. Ammonium carbonate can be evaporated from solution and recovered for re-use, leaving an extremely compact volume of fission products, transactinides, and uranium. Stack emissions are predicted to be less toxic, less radioactive, chemically simpler, and simpler to treat than those from the conventional PUREX process.

  20. Structural and magnetic properties of manganese zinc ferrite nanoparticles prepared by solution combustion method using mixture of fuels

    Energy Technology Data Exchange (ETDEWEB)

    Angadi, V. Jagadeesha; Rudraswamy, B. [Department of Physics, Bangalore University, Bangalore 560056 (India); Sadhana, K. [Department of Physics, University College of Science, Osmania University, Saifabad, Hyderabad 500004 (India); Praveena, K., E-mail: praveenaou@gmail.com [School of Physics, Eternal University, Baru Sahib 173101, Himachal Pradesh (India)

    2016-07-01

    The structural analysis and magnetic investigation Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} with stoichiometry (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) were synthesized by solution combustion method using mixture of fuel this is first of its kind. As synthesized Mn–Zn nanoferrites were characterized by X-ray Diffractometer (XRD), Transmission electron microscopy (TEM) at room temperature. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (f{sub r}) was increased with the increase in grain size. The Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM). It was observed that the real and imaginary part of permeability (μ′ and μ″), saturation magnetization (M{sub s}), remanance magnetization (M{sub r}) and magneton number (M{sub r}/M{sub s}) were decreases gradually with increasing Zn{sup 2+} concentration. The decrease in the saturation magnetization may be explained as, the Zn{sup 2+} concentration increases the relative number of ferric ions on the A sites diminishes and this reduces the A–B interaction. Hence synthesized materials are good for high frequency applications. - Highlights: • Mixture of fuels used for synthesis. • Preferred existence of Fe{sup 3+} oxidation states. • Reduction in magnetic interaction between Fe ions due to Zn{sup 2+} dilutions. • These materials are useful for high frequency applications.

  1. In-Core Fuel Managements for PWRs: Investigation on solution for optimal utilization of PWR fuel through the use of fuel assemblies with differently enriched {sup 235}U fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Sara

    2004-04-01

    A possibility for more efficient use of the nuclear fuel in a pressurized water reactor is investigated. The alternative proposed here consists of the implementation of PWR fuel assemblies with differently enriched {sup 235}U fuel pins. This possibility is examined in comparison with the standard assembly design. The comparison is performed both in terms of single assembly performance and in the terms of nuclear reactor core performance and fuel utility. For the evaluation of the actual performance of the new assembly types, 5 operated fuel core sequences of R3 (Ringhals' third unit), for the period 1999 - 2004 (cycles 17 - 21) were examined. For every cycle, the standard fresh fuel assemblies have been identified and taken as reference cases for the study of the new type of assemblies with differently enriched uranium rods. In every cycle, assemblies with and without burnable absorber are freshly loaded into the core. The axial enrichment distribution is kept uniform, allowing for a radial (planar) enrichment level distribution only. At an assembly level, it has been observed that the implementation of the alternative enrichment configuration can lead to lower and flatter internal peaking factor distribution with respect to the uniformly enriched reference assemblies. This can be achieved by limiting the enrichment levels distribution to a rather narrow range. The highest enrichment level chosen has the greatest impact on the power distribution of the assemblies. As it increases, the enrichment level drives the internal peaking factor to greater values than in the reference assemblies. Generally, the highest enrichment level that would allow an improvement in the power performance of the assembly lies between 3.95 w/o and 4.17 w/o. The highest possible enrichment level depends on the average enrichment of the overall assembly, which is kept constant to the average enrichment of the reference assemblies. The improvements that can be obtained at this level are

  2. Effects of dissolved Ca2+, Mg2+, and Na+ ions on the supramolecular aggregation of natural organic matter in aqueous solutions

    Science.gov (United States)

    Ahn, W.; Kalinichev, A. G.; Clark, M. M.

    2008-12-01

    The complexation of natural organic matter (NOM) with metal ions, minerals and organic species in soil and water allows NOM to form water-soluble and water-insoluble aggregates of widely differing chemical and biological stabilities. Metal-NOM interaction induces strong correlations between the concentration of natural organic matter and the speciation, solubility and toxicity of many metals in the environment. In water purification and desalination, NOM is also implicated in fouling of nanofiltration and reverse osmosis membranes, either as the primary foulant or as a conditioning layer for microbial attachment ("biofouling"). In this work we investigated the effects of various metal ions on NOM aggregation in aqueous solutions, by a combination of dynamic light scattering (DLS), small angle neutron scattering (SANS) and large-scale molecular dynamics (MD) computer simulations. This allows a detailed molecular-scale statistical analysis of the size and the structural topology of metal-NOM aggregates. The DLS measurements show that Ca2+ ions present in a Suwannee River NOM (SRNOM) solution lead to the formation of a wide range of supramolecular structures with sizes between 100 and 1,000 nm. In contrast, Mg2+ and Na+ do not affect the aggregation of SRNOM as strongly. SANS data are inconclusive but indicate the presence of quite large (>50 nm) fractal particles formed presumably through a cluster-cluster aggregation. MD simulations confirm these observations and show that NOM can aggregate in aqueous solutions by two different mechanisms. On the one hand, NOM molecules can spontaneously aggregate by hydrogen bonding between their functional groups when only Na+ and Mg2+ are present as background cations. This promotes the formation of uniformly shaped NOM clusters. On the other hand, if Ca2+ ions are present in solution, they can more strongly bind two different NOM molecules by co-complexing the carboxylate groups, thus promoting the formation of longer linear and

  3. Erosion patterns on dissolving blocks

    Science.gov (United States)

    Courrech du Pont, Sylvain; Cohen, Caroline; Derr, Julien; Berhanu, Michael

    2016-04-01

    Patterns in nature are shaped under water flows and wind action, and the understanding of their morphodynamics goes through the identification of the physical mechanisms at play. When a dissoluble body is exposed to a water flow, typical patterns with scallop-like shapes may appear [1,2]. These shapes are observed on the walls of underground rivers or icebergs. We experimentally study the erosion of dissolving bodies made of salt, caramel or ice into water solutions without external flow. The dissolving mixture, which is created at the solid/liquid interface, undergoes a buoyancy-driven instability comparable to a Rayleigh-Bénard instability so that the dissolving front destabilizes into filaments. This mechanism yields to spatial variations of solute concentration and to differential dissolution of the dissolving block. We first observe longitudinal stripes with a well defined wavelength, which evolve towards chevrons and scallops that interact and move again the dissolving current. Thanks to a careful analysis of the competing physical mechanisms, we propose scaling laws, which account for the characteristic lengths and times of the early regime in experiments. The long-term evolution of patterns is understood qualitatively. A close related mechanism has been proposed to explain structures observed on the basal boundary of ice cover on brakish lakes [3] and we suggest that our experiments are analogous and explain the scallop-like patterns on iceberg walls. [1] P. Meakin and B. Jamtveit, Geological pattern formation by growth and dissolution in aqueous systems, Proc. R. Soc. A 466, 659-694 (2010). [2] P.N. Blumberg and R.L. Curl, Experimental and theoretical studies of dissolution roughness, J. Fluid Mech. 65, 735-751 (1974). [3] L. Solari and G. Parker, Morphodynamic modelling of the basal boundary of ice cover on brakish lakes, J.G.R. 118, 1432-1442 (2013).

  4. Characteristics and behavior of emulsion at nuclear fuel reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Gonda, K.; Nemoto, T.; Oka, K.

    1982-05-01

    The characteristics and behavior of the emulsion formed in mixer-settlers during nuclear fuel reprocessing were studied with the dissolver solution of spent fuel burned up to 28,000 MWd/MTU and a palladium colloidal solution, respectively. The emulsion was observed to be oil in water where nonsoluble residues of spent fuel were condensed as emulsifiers. Emulsion formed at interfaces in the settler showed electric conductivity due to continuity of the aqueous phase of the emulsion and viscosity due to the creamy state of the emulsion. The higher the palladium particle concentration was, the larger the amount of emulsion formed. This result agreed well with experience obtained in the Tokai Reprocessing Plant operation that both nonsoluble residues and emulsion formation increased remarkably on fuels in which burnup exceeded 20 000 MWd/MTU.

  5. Antitubercular activity of ZnO nanoparticles prepared by solution combustion synthesis using lemon juice as bio-fuel.

    Science.gov (United States)

    Gopala Krishna, Prashanth; Paduvarahalli Ananthaswamy, Prashanth; Trivedi, Priyanka; Chaturvedi, Vinita; Bhangi Mutta, Nagabhushana; Sannaiah, Ananda; Erra, Amani; Yadavalli, Tejabhiram

    2017-06-01

    In this study, we report the synthesis, structural and morphological characteristics of zinc oxide (ZnO) nanoparticles using solution combustion synthesis method where lemon juice was used as the fuel. In vitro anti-tubercular activity of the synthesized ZnO nanoparticles and their biocompatibility studies, both in vitro and in vivo were carried out. The synthesized nanoparticles showed inhibition of Mycobacterium tuberculosis H37Ra strain at concentrations as low as 12.5μg/mL. In vitro cytotoxicity study performed with normal mammalian cells (L929, 3T3-L1) showed that ZnO nanoparticles are non-toxic with a Selectivity Index (SI) >10. Cytotoxicity performed on two human cancer cell lines DU-145 and Calu-6 indicated the anti-cancer activity of ZnO nanoparticles at varied concentrations. Results of blood hemolysis indicated the biocompatibility of ZnO nanoparticles. Furthermore, in vivo toxicity studies of ZnO nanoparticles conducted on Swiss albino mice (for 14days as per the OECD 423 guidelines) showed no evident toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. In-Core Fuel Managements for PWRs: Investigation on solution for optimal utilization of PWR fuel through the use of fuel assemblies with differently enriched {sup 235}U fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Sara

    2004-04-01

    A possibility for more efficient use of the nuclear fuel in a pressurized water reactor is investigated. The alternative proposed here consists of the implementation of PWR fuel assemblies with differently enriched {sup 235}U fuel pins. This possibility is examined in comparison with the standard assembly design. The comparison is performed both in terms of single assembly performance and in the terms of nuclear reactor core performance and fuel utility. For the evaluation of the actual performance of the new assembly types, 5 operated fuel core sequences of R3 (Ringhals' third unit), for the period 1999 - 2004 (cycles 17 - 21) were examined. For every cycle, the standard fresh fuel assemblies have been identified and taken as reference cases for the study of the new type of assemblies with differently enriched uranium rods. In every cycle, assemblies with and without burnable absorber are freshly loaded into the core. The axial enrichment distribution is kept uniform, allowing for a radial (planar) enrichment level distribution only. At an assembly level, it has been observed that the implementation of the alternative enrichment configuration can lead to lower and flatter internal peaking factor distribution with respect to the uniformly enriched reference assemblies. This can be achieved by limiting the enrichment levels distribution to a rather narrow range. The highest enrichment level chosen has the greatest impact on the power distribution of the assemblies. As it increases, the enrichment level drives the internal peaking factor to greater values than in the reference assemblies. Generally, the highest enrichment level that would allow an improvement in the power performance of the assembly lies between 3.95 w/o and 4.17 w/o. The highest possible enrichment level depends on the average enrichment of the overall assembly, which is kept constant to the average enrichment of the reference assemblies. The improvements that can be obtained at this level are

  7. Proceedings of hydrogen and fuel cells 2007 international conference and trade show : international partnerships for global energy solutions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This conference discussed all aspects of hydrogen and fuel cells, with particular focus on environmental issues; policy and economics; hydrogen investment; trading pollution credits; international partnerships; and, climate change. The session on hydrogen fuels addressed hydrogen production from wind, solar, clean coal, nuclear and biomass through electrolysis and reforming thermochemical processes. Hydrogen distribution and transportation was also discussed with reference to pipelines, ships, trains and portable micro power. Storage of liquid hydrogen, carbon, compressed gas and hydrides was reviewed along with integrated systems, codes, standards and computerized simulation. Innovative technologies that have emerged from recent fuel cell research and development activities were also highlighted with particular reference to fuel cell components, fuel cell stacks, fuel cell systems, fuel cell materials, fuel cell design and fuel cell manufacturing. The current use of monitoring and sensor technologies was also reviewed. The conference highlighted fuel cell applications in residential and commercial installations, portable applications, transportation applications, distributed power generation and combined heat and power. All 54 presentations from the conference have been catalogued separately for inclusion in this database. refs., tabs., figs.

  8. Reprocessing of LEU U-Mo Dispersion and Monolithic Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, G.F.; Jerden, J.; Stepinski, D.C.; Figueroa, J.; Williamson, M.A.; Kleeck, M.A. Van; Blaskovitz, R.J.; Ziegler, A.J.; Maggos, L.E.; Swanson, J.; Fortner, J.; Bakel, A.J. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

    2011-07-01

    For conversion of high-performance research reactors from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, a fuel material with a higher density than uranium aluminide is required. Development studies are underway to develop U-Mo dispersion and monolithic fuels for conversion of several high- performance reactors. For dispersion fuels, development is narrowing down to a composition of U-7Mo dispersed in an aluminium matrix containing {approx}5% silicon. For monolithic fuels to be used in high performance research reactors in the United States, a zirconium-bonded U-10Mo foil appears to be the fuel of choice. For conversion to be realized a back-end disposition path is required for both fuels; one disposition pathway is reprocessing. Argonne National Laboratory is developing a pyroprocess for reprocessing spent monolithic fuel. Pyroprocessing was chosen over conventional aqueous solvent extraction due to the necessity of adding fluoride to the fuel-dissolution solution in order to dissolve the zirconium bonding layer on the U-Mo fuel. The proposed flowsheet and development activities will be described. A literature survey points to the ability to reprocess U-Mo dispersion fuels by an aqueous process, but due to several special characteristics of the fuel, the solvent-extraction flowsheets will be a departure from that normally used for the reprocessing of power reactor fuel. Special concerns that must be addressed in reprocessing these fuels are, for example, the low solubilities of uranyl molybdate, molybdic acid, and silicic acid in nitric acid solutions. This paper will address these concerns and development activities required to overcome them. (author)

  9. Photoluminescent Detection of Dissolved Underwater Trace Explosives

    OpenAIRE

    2010-01-01

    A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial component...

  10. Ground-fire effects on the composition of dissolved and total organic matter in forest floor and soil solutions from Scots pine forests in Germany: new insights from solid state 13C NMR analysis

    Science.gov (United States)

    Näthe, Kerstin; Michalzik, Beate; Levia, Delphis; Steffens, Markus

    2016-04-01

    Fires represent an ecosystem disturbance and are recognized to seriously pertubate the nutrient budgets of forested ecosystems. While the effects of fires on chemical, biological, and physical soil properties have been intensively studied, especially in Mediterranean areas and North America, few investigations examined the effects of fire-induced alterations in the water-bound fluxes and the chemical composition of dissolved and particulate organic carbon and nitrogen (DOC, POC, DN, PN). The exclusion of the particulate organic matter fraction (0.45 μm floor (FF) and soil solutions (A, B horizon) from Scots pine forests in Germany. In relation to control sites, we test the effects of low-severity fires on: (1) the composition of DOM and TOM in forest floor and soil solutions; and (2) the translocated amount of particulate in relation to DOC and DN into the subsoil. The project aims to uncover the mechanisms of water-bound organic matter transport along an ecosystem profile and its compositional changes following a fire disturbance. Forest floor and soil solutions were fortnightly sampled from March to December 2014 on fire-manipulated and control plots in a Scots pine forest in Central Germany. Shortly after the experimental duff fire in April 2014 pooled solutions samples were taken for solid-state 13C NMR spectroscopy to characterize DOM (filtered solution < 0.8μm pore size) and TOM in unfiltered solutions. Independent from fire manipulation, the composition of TOM was generally less aromatic (aromaticity index [%] according to Hatcher et al., 1981) with values between 18 (FF) - 25% (B horizon) than the DOM fraction with 23 (FF) - 27% (B horizon). For DOM in FF solution, fire manipulation caused an increase in aromaticity from 23 to 27% compared to the control, due to an increase of the aryl-C and a decrease of the O-alkyl-C and alkyl-C signal. Fire effects were leveled out in the mineral soil. For TOM, fire effects became notable only in the A horizon

  11. Extraction Equilibrium of Mn2+, Ca2+, and Mg2+ from Chloride Solutions by Di(2-ethylhexyl)phosphoric Acid Dissolved in Kerosene

    Science.gov (United States)

    Zhang, Chuanfu; Cao, Wenxin; Zhan, Jing; Ding, Fenghua; Hwang, Jiann-Yang

    2015-05-01

    The presence of calcium and magnesium affects the purity of the final product MnCl2 in hydrometallurgical treatment processes. The solvent extraction method can be used to separate Ca2+ and Mg2+ from Mn2+ solutions containing impurity ions such as Ca2+ and Mg2+. This article aims to investigate the single-stage extraction equilibrium of Ca2+, Mg2+, and Mn2+ in chloride medium using di(2-ethylhexyl)phosphoric acid in kerosene (O:A = 1:1). The results show that the pH0.5 values are 1.11, 1.56, and 2.18 for Ca2+, Mn2+, and Mg2+, respectively. The mechanism of extraction and stoichiometries of metal-containing extracted species were illustrated based on a slope analysis. The composition of the extracted species in the organic phase is proposed to be MnR2·R2H2, CaR2·R2H2, and MgR2·(R2H2)2, respectively.

  12. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil and nucl......A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  13. Solutions for the durability of fuel cells in vehicle applications%车用燃料电池耐久性的解决策略

    Institute of Scientific and Technical Information of China (English)

    衣宝廉; 侯明

    2011-01-01

    车用燃料电池的耐久性是制约其商业化的技术挑战之一。该文从车用燃料电池材料与系统两方面论述了其衰减机理与解决对策。系统方面主要分析了动态工况、启/停、低载怠速等过程中发生的反应气饥饿、动态电位循环以及高电位对燃料电池的影响及解决对策;材料方面阐述了催化剂与载体、质子交换膜、膜电极组件以及双极板在提高稳定性等方面的研究进展与发展方向。燃料电池的研发要坚持采用材料与系统改进并行的原则,现阶段可在原有材料基础上利用系统控制策略的改进,提高车用燃料电池系统的使用寿命,但是这在一定程度上会增加系统复杂性;长远地还要持%Durability is one of the challenges for the commercialization of fuel cell vehicles. The mechanisms and solutions for fuel cell degradation are elucidated from the material and system point of view. In the aspect of fuel cell system, typical operating processes are analyzed, such as driving cycles, start-stop, low load and idle conditions, in which reactant starvation, dynamic potential scanning and local high potential have significant impacts on the fuel cell durability. Feasible strategies are also discussed for mitigating the degradation. The current state and perspective are addressed on the durability of key material in fuel cells, i.e., catalyst, catalyst support, proton exchange membrane, membrane electrode assembly and bipolar plate. The effective methods to enhance the fuel cell durability should be based on both the material innovation and system improvement. Currently, the improvement on system control strategy is a feasible way to prolong fuel cell lifetime although it has been result in a complex system. Nevertheless, material innovation is a long term task to promote the fuel cell durability. Fuel cells with advanced durable materials and simply system is a desirable goal for the fuel cell vehicle application.

  14. A 17-year record of environmental tracers in spring discharge, Shenandoah National Park, Virginia, USA: use of climatic data and environmental conditions to interpret discharge, dissolved solutes, and tracer concentrations

    Science.gov (United States)

    Busenberg, Eurybiades; Plummer, L. Niel

    2014-01-01

    A 17-year record (1995–2012) of a suite of environmental tracer concentrations in discharge from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park (SNP), Virginia, USA, reveals patterns and trends that can be related to climatic and environmental conditions. These data include a 12-year time series of monthly sampling at five springs, with measurements of temperature, specific conductance, pH, and discharge recorded at 30-min intervals. The monthly measurements include age tracers (CFC-11, CFC-12, CFC-113, CFC-13, SF6, and SF5CF3), dissolved gases (N2, O2, Ar, CO2, and CH4), stable isotopes of water, and major and trace inorganic constituents. The chlorofluorocarbon (CFC) and sulfur hexafluoride (SF6) concentrations (in pptv) in spring discharge closely follow the concurrent monthly measurements of their atmospheric mixing ratios measured at the Air Monitoring Station at Big Meadows, SNP, indicating waters 0–3 years in age. A 2-year (2001–2003) record of unsaturated zone air displayed seasonal deviations from North American Air of ±10 % for CFC-11 and CFC-113, with excess CFC-11 and CFC-113 in peak summer and depletion in peak winter. The pattern in unsaturated zone soil CFCs is a function of gas solubility in soil water and seasonal unsaturated zone temperatures. Using the increase in the SF6 atmospheric mixing ratio, the apparent (piston flow) SF6 age of the water varied seasonally between about 0 (modern) in January and up to 3 years in July–August. The SF6 concentration and concentrations of dissolved solutes (SiO2, Ca2+, Mg2+, Na+, Cl−, and HCO3−) in spring discharge demonstrate a fraction of recent recharge following large precipitation events. The output of solutes in the discharge of springs minus the input from atmospheric deposition per hectare of watershed area (mol ha−1 a−1) were approximately twofold greater in watersheds draining the regolith of Catoctin metabasalts than that of granitic

  15. A multiphase interfacial model for the dissolution of spent nuclear fuel

    Science.gov (United States)

    Jerden, James L.; Frey, Kurt; Ebert, William

    2015-07-01

    The Fuel Matrix Dissolution Model (FMDM) is an electrochemical reaction/diffusion model for the dissolution of spent uranium oxide fuel. The model was developed to provide radionuclide source terms for use in performance assessment calculations for various types of geologic repositories. It is based on mixed potential theory and consists of a two-phase fuel surface made up of UO2 and a noble metal bearing fission product phase in contact with groundwater. The corrosion potential at the surface of the dissolving fuel is calculated by balancing cathodic and anodic reactions occurring at the solution interfaces with UO2 and NMP surfaces. Dissolved oxygen and hydrogen peroxide generated by radiolysis of the groundwater are the major oxidizing agents that promote fuel dissolution. Several reactions occurring on noble metal alloy surfaces are electrically coupled to the UO2 and can catalyze or inhibit oxidative dissolution of the fuel. The most important of these is the oxidation of hydrogen, which counteracts the effects of oxidants (primarily H2O2 and O2). Inclusion of this reaction greatly decreases the oxidation of U(IV) and slows fuel dissolution significantly. In addition to radiolytic hydrogen, large quantities of hydrogen can be produced by the anoxic corrosion of steel structures within and near the fuel waste package. The model accurately predicts key experimental trends seen in literature data, the most important being the dramatic depression of the fuel dissolution rate by the presence of dissolved hydrogen at even relatively low concentrations (e.g., less than 1 mM). This hydrogen effect counteracts oxidation reactions and can limit fuel degradation to chemical dissolution, which results in radionuclide source term values that are four or five orders of magnitude lower than when oxidative dissolution processes are operative. This paper presents the scientific basis of the model, the approach for modeling used fuel in a disposal system, and preliminary

  16. Experimental determination and chemical modelling of radiolytic processes at the spent fuel/water interface. Experiments carried out in carbonate solutions in absence and presence of chloride

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Jordi; Cera, Esther; Grive, Mireia; Duro, Lara [Enviros Spain SL (Spain); Eriksen, Trygve [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Nuclear Chemistry

    2003-01-01

    We report on the recent experimental and modelling results of a research programme that started in 1995. The aim has been to understand the kinetic and thermodynamic processes that control the radiolytic generation of oxidants and reductants at the spent fuel water interface and their consequences for spent fuel matrix stability and radionuclide release. This has been done by carrying out well-controlled dissolution experiments of PWR Ringhals spent fuel fragments in an initially anoxic closed system and by using different solution compositions. Experimental series started with several tests carried out with deionised water as solvent, in a second phase experiments were conducted with 10 mM bicarbonate solutions. New experimental series were set up during the last two years by using the same bicarbonate content in solutions with varying NaCl concentrations in order to ascertain the role of this ligand on the radiolytic products and its consequence for radionuclide release. The selected NaCl concentrations are in the range of 0.1 to 10 mM. Experimental data shows that uranium dissolution at early contact times is controlled by the oxidation of the UO{sub 2} matrix. This process controls the co-dissolution of most of the analysed radionuclides, including Sr, Mo, Tc, Np and surprisingly enough, Cs. In the overall the release rates for U and the matrix associated radionuclides are in the range of 10{sup -6} moles/day with a clear decreasing trend with exposure time and after 2 years the initial release rates have decreased down to 3x10{sup -8} moles/day. The solubility of the released actinides appears to be limited by the formation of An(IV) hydroxide phases, although Np concentrations in solution did not reach solubility levels during the time intervals of the present tests. No secondary solid phase appears to control the solubility of the rest of the elements.

  17. Evaluation of dissolution rate on high plutonium content MOX fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sugaya, Shinichi; Kurita, Ichiro; Endo, Hideo; Higuchi, Hidetoshi; Kihara, Yoshiyuki [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Ogasawara, Masahiro; Shinada, Masanori; Kowata, Masato [Inspection Development Company Ltd., Tokai, Ibaraki (Japan)

    2002-06-01

    The dissolution rate of high Pu content MOX fuel into nitric acid was measured as a function of Pu content. MOX fuel samples, pressed and sintered, were dissolved in 7 M of boiling nitric acid, and the dissolution rate was measured by analyzing the Pu and U concentration in the solution. The dissolution rate of MOX fuel tended to decrease with the increase in the Pu content and was reduced after 6 hours of dissolution. These results agreed well with previous ones, but the dissolution rate was 3-6 times faster than those. It is estimated that the cause of this difference was due to underestimation of the surface area of MOX fuel powder and the difference of the MOX O/M ratio. (author)

  18. SOLUTIONING

    Directory of Open Access Journals (Sweden)

    Maria de Hoyos Guajardo, Ph.D. Candidate, M.Sc., B.Eng.

    2004-11-01

    Full Text Available The theory that is presented below aims to conceptualise how a group of undergraduate students tackle non-routine mathematical problems during a problem-solving course. The aim of the course is to allow students to experience mathematics as a creative process and to reflect on their own experience. During the course, students are required to produce a written ‘rubric’ of their work, i.e., to document their thoughts as they occur as well as their emotionsduring the process. These ‘rubrics’ were used as the main source of data.Students’ problem-solving processes can be explained as a three-stage process that has been called ‘solutioning’. This process is presented in the six sections below. The first three refer to a common area of concern that can be called‘generating knowledge’. In this way, generating knowledge also includes issues related to ‘key ideas’ and ‘gaining understanding’. The third and the fourth sections refer to ‘generating’ and ‘validating a solution’, respectively. Finally, once solutions are generated and validated, students usually try to improve them further before presenting them as final results. Thus, the last section deals with‘improving a solution’. Although not all students go through all of the stages, it may be said that ‘solutioning’ considers students’ main concerns as they tackle non-routine mathematical problems.

  19. Organic fuel cells and fuel cell conducting sheets

    Science.gov (United States)

    Masel, Richard I.; Ha, Su; Adams, Brian

    2007-10-16

    A passive direct organic fuel cell includes an organic fuel solution and is operative to produce at least 15 mW/cm.sup.2 when operating at room temperature. In additional aspects of the invention, fuel cells can include a gas remover configured to promote circulation of an organic fuel solution when gas passes through the solution, a modified carbon cloth, one or more sealants, and a replaceable fuel cartridge.

  20. Studies on PEM fuel cell noble metal catalyst dissolution

    DEFF Research Database (Denmark)

    Andersen, S. M.; Grahl-Madsen, L.; Skou, E. M.

    2011-01-01

    A combination of electrochemical, spectroscopic and gravimetric methods was carried out on Proton Exchange Membrane (PEM) fuel cell electrodes with the focus on platinum and ruthenium catalysts dissolution, and the membrane degradation. In cyclic voltammetry (CV) experiments, the noble metals were...... found to dissolve in 1 M sulfuric acid solution and the dissolution increased exponentially with the upper potential limit (UPL) between 0.6 and 1.6 vs. RHE. 2-20% of the Pt (depending on the catalyst type) was found to be dissolved during the experiments. Under the same conditions, 30-100% of the Ru...... (depending on the catalyst type) was found to be dissolved. The faster dissolution of ruthenium compared to platinum in the alloy type catalysts was also confirmed by X-ray diffraction measurements. The dissolution of the carbon supported catalyst was found one order of magnitude higher than the unsupported...

  1. Dissolution performance of plutonium nitride based fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Aneheim, E.; Hedberg, M. [Nuclear Chemistry, Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivaegen 4, Gothenburg, SE41296 (Sweden)

    2016-07-01

    Nitride fuels have been regarded as one viable fuel option for Generation IV reactors due to their positive features compared to oxides. To be able to close the fuel cycle and follow the Generation IV concept, nitrides must, however, demonstrate their ability to be reprocessed. This means that the dissolution performance of actinide based nitrides has to be thoroughly investigated and assessed. As the zirconium stabilized nitrides show even better potential as fuel material than does the pure actinide containing nitrides, investigations on the dissolution behavior of both PuN and (Pu,Zr)N has been undertaken. If possible it is desirable to perform the fuel dissolutions using nitric acid. This, as most reprocessing strategies using solvent-solvent extraction are based on a nitride containing aqueous matrix. (Pu,Zr)N/C microspheres were produced using internal gelation. The spheres dissolution performance was investigated using nitric acid with and without additions of HF and Ag(II). In addition PuN fuel pellets were produced from powder and their dissolution performance were also assessed in a nitric acid based setting. It appears that both PuN and (Pu,Zr)N/C fuel material can be completely dissolved in nitric acid of high concentration with the use of catalytic amounts of HF. The amount of HF added strongly affects dissolution kinetics of (Pu, Zr)N and the presence of HF affects the 2 solutes differently, possibly due to inhomogeneity o the initial material. Large additions of Ag(II) can also be used to facilitate the dissolution of (Pu,Zr)N in nitric acid. PuN can be dissolved by pure nitric acid of high concentration at room temperature while (Pu, Zr)N is unaffected under similar conditions. At elevated temperature (reflux), (Pu,Zr)N can, however, also be dissolved by concentrated pure nitric acid.

  2. Effects of Fuel to Synthesis of CaTiO3 by Solution Combustion Synthesis for High-Level Nuclear Waste Ceramics.

    Science.gov (United States)

    Jung, Choong-Hwan; Kim, Yeon-Ku; Han, Young-Min; Lee, Sang-Jin

    2016-02-01

    A solution combustion process for the synthesis of perovskite (CaTiO3) powders is described. Perovskite is one of the crystalline host matrics for the disposal of high-level radioactive wastes (HLW) because it immobilizes Sr and Lns elements by forming solid solutions. Solution combustion synthesis, which is a self-sustaining oxi-reduction reaction between nitrate and organic fuel, the exothermic reaction, and the heat evolved convert the precursors into their corresponding oxide products above 1100 degrees C in air. To investigate the effects of amino acid on the combustion reaction, various types of fuels were used; a glycine, amine and carboxylic ligand mixture. Sr, La and Gd-nitrate with equivalent amounts of up to 20% of CaTiO3 were mixed with Ca and Ti nitrate and amino acid. X-ray diffraction analysis, SEM and TEM were conducted to confirm the formed phases and morphologies. While powders with an uncontrolled shape are obtained through a general oxide-route process, Ca(Sr, Lns)TiO3 powders with micro-sized soft agglomerates consisting of nano-sized primary particles can be prepared using this method.

  3. Dissolution Flowsheet for High Flux Isotope Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Karay, N. S [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-27

    As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U3O8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H2. The HFIR fuel cores will be dissolved and the recovered U will be down-blended into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H2 and other permanent gases in the dissolution offgas allowing the development of H2 generation rate profiles. The H2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the calculated lower

  4. Dissolution Flowsheet for High Flux Isotope Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Karay, N. S [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-27

    As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U3O8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H2. The HFIR fuel cores will be dissolved and the recovered U will be down-blended into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy, and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H2 and other permanent gases in the dissolution offgas, allowing the development of H2 generation rate profiles. The H2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the

  5. Application of electrochemical impedance spectroscopy for fuel cell characterization: PEFC and oxygen reduction reaction in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, N.; Friedrich, K.A. [German Aerospace Center, Institute for Technical Thermodynamics, Stuttgart (Germany)

    2009-06-15

    The most common method used to characterise the electrochemical performance of fuel cells is the recording of current/voltage U(i) curves. Separation of electrochemical and ohmic contributions to the U(i) characteristics requires additional experimental techniques like electrochemical impedance spectroscopy (EIS). The application of EIS is an approach to determine parameters which have proved to be indispensable for the characterisation and development of all types of fuel cell electrodes and electrolyte electrode assemblies [1]. In addition to EIS semi-empirical approaches based on simplified mathematical models can be used to fit experimental U(i) curves [2]. By varying the operating conditions of the fuel cell and by the simulation of the measured EIS with an appropriate equivalent circuit, it is possible to split the cell impedance into electrode impedances and electrolyte resistance. Integration in the current density domain of the individual impedance elements enables the calculation of the individual overpotentials in the fuel cell (PEFC) and the assignment of voltage loss to the different processes. In case of using a three electrode cell configuration with a reference electrode, one can directly determine the corresponding overvoltage. For the evaluation of the measured impedance spectra the porous electrode model of Goehr [3] was used. This porous electrode model includes different impedance contributions like impedance of the interface porous layer/pore, interface porous layer/electrolyte, interface porous layer/bulk, impedance of the porous layer and impedance of the pores filled by electrolyte. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Fuel flexible fuel injector

    Science.gov (United States)

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  7. Effect of Greenhouse Gases Dissolved in Seawater.

    Science.gov (United States)

    Matsunaga, Shigeki

    2015-12-30

    A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region.

  8. Effect of Greenhouse Gases Dissolved in Seawater

    OpenAIRE

    Shigeki Matsunaga

    2015-01-01

    A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence o...

  9. Fuel mediated solution combustion synthesis of ZnO supported gold clusters and nanoparticles and their catalytic activity and in vitro cytotoxicity.

    Science.gov (United States)

    Chanu, T Inakhunbi; Muthukumar, Thangavelu; Manoharan, Periakaruppan T

    2014-11-21

    Nanocomposites of gold nanoparticles and semiconductor ZnO with wurtzite structure, made by solution combustion synthesis (SCS), as a function of the Zn/fuel ratio with polyethylene glycol (PEG) as fuel exhibit the presence of both nanoparticles and clusters. Atomic gold clusters present on the surface of ZnO nanorods which can be identified by XPS and SEM are easily monitored and characterized by positive ion MALDI experiments as mostly odd numbered clusters, Au3 to Au11 in decreasing amounts. Low concentrations of the fuel produce AuClO and nanoparticles (NPs), with no clusters. Au-ZnO nanocomposites at all [Au] exhibit single blue shifted plasmon absorption and corresponding photoluminescence (PL). Increasing particle size prefers surface plasmon resonance (SPR) scattering of metal that could lead to PL enhancement; however, available ZnO surface in the Au-ZnO composite becomes more important than the particle size of the composite with higher [Au]. The catalytic activity of these Au-ZnO nanocomposites tested on 4-nitrophenol clearly revealed the presence of an intermediate with both NPs and clusters playing different roles. An in vitro study of cytotoxicity on MCF-7 cell lines revealed that these gold nanostructures have turned out to be powerful nanoagents for destruction of cancer cells even with small amounts of gold particles/clusters. The nanorods of ZnO, known to be nontoxic to normal cells, play a lesser role in the anticancer activity of these Au-ZnO nanocomposites.

  10. Method to Estimate the Dissolved Air Content in Hydraulic Fluid

    Science.gov (United States)

    Hauser, Daniel M.

    2011-01-01

    In order to verify the air content in hydraulic fluid, an instrument was needed to measure the dissolved air content before the fluid was loaded into the system. The instrument also needed to measure the dissolved air content in situ and in real time during the de-aeration process. The current methods used to measure the dissolved air content require the fluid to be drawn from the hydraulic system, and additional offline laboratory processing time is involved. During laboratory processing, there is a potential for contamination to occur, especially when subsaturated fluid is to be analyzed. A new method measures the amount of dissolved air in hydraulic fluid through the use of a dissolved oxygen meter. The device measures the dissolved air content through an in situ, real-time process that requires no additional offline laboratory processing time. The method utilizes an instrument that measures the partial pressure of oxygen in the hydraulic fluid. By using a standardized calculation procedure that relates the oxygen partial pressure to the volume of dissolved air in solution, the dissolved air content is estimated. The technique employs luminescent quenching technology to determine the partial pressure of oxygen in the hydraulic fluid. An estimated Henry s law coefficient for oxygen and nitrogen in hydraulic fluid is calculated using a standard method to estimate the solubility of gases in lubricants. The amount of dissolved oxygen in the hydraulic fluid is estimated using the Henry s solubility coefficient and the measured partial pressure of oxygen in solution. The amount of dissolved nitrogen that is in solution is estimated by assuming that the ratio of dissolved nitrogen to dissolved oxygen is equal to the ratio of the gas solubility of nitrogen to oxygen at atmospheric pressure and temperature. The technique was performed at atmospheric pressure and room temperature. The technique could be theoretically carried out at higher pressures and elevated

  11. Aircraft and Bases Powered by Compact Nuclear Reactors: Solutions to Projecting Power in Highly Contested Environments and Fossil Fuel Dependence

    Science.gov (United States)

    2015-05-01

    decline.20 Since 2008, improvements in fossil fuel extraction techniques, such as fracking in the United States, have delayed the inevitable and probably...higher US production due to fracking and inaction by the Organization of the Petroleum Exporting Countries (OPEC).25 Assuming this relaxation does not... fracking techniques, eventually even the most ingenious extraction techniques will not be enough for supply to keep up with demand, and humans will

  12. The impact of new cathode materials relative to baseline performance of microbial fuel cells all with the same architecture and solution chemistry

    KAUST Repository

    Yang, Wulin

    2017-04-21

    Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have previously hindered direct comparisons of improvements in power production due to new cathode materials. However, one common reactor design has now been used in many different laboratories around the world under similar operating conditions based on using: a graphite fiber brush anode, a platinum cathode catalyst, a single-chamber cube-shaped (4-cm) MFC with a 3-cm diameter anolyte chamber, 50 mM phosphate buffer, and an acetate fuel. Analysis of several publications over 10 years from a single laboratory showed that even under such identical operational conditions, maximum power densities varied by 15%, with an average of 1.36 ± 0.20 W m–2 (n=24), normalized to cathode projected area (34 W m–3 liquid volume). In other laboratories, maximum power was significantly less, with an average of 1.03 ± 0.46 W m–2 (n=11), despite identical conditions. One likely reason for the differences in power is cathode age. Power production with Pt catalyst cathodes significantly declined after one month of operation or more to 0.87 ± 0.31 W m–2 (n=18) based on studies where cathode aging was examined, while in many studies the age of the cathode was not reported. Using these studies as a performance baseline, we review the claims of improvements in power generation due to new anode or cathode materials, or changes in solution conductivities and substrates.

  13. Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities

    KAUST Repository

    Hoskins, Daniel L.

    2014-11-01

    © 2014 Elsevier Ltd. Separators are used to protect cathodes from biofouling and to avoid electrode short-circuiting, but they can adversely affect microbial fuel cell (MFC) performance. A spray method was used to apply a polyvinyl alcohol (PVA) separator to the cathode. Power densities were unaffected by the PVA separator (339 ± 29 mW/m2), compared to a control lacking a separator in a low conductivity solution (1mS/cm) similar to wastewater. Power was reduced with separators in solutions typical of laboratory tests (7-13 mS/cm), compared to separatorless controls. The PVA separator produced more power in a separator assembly (SEA) configuration (444 ± 8 mW/m2) in the 1mS/cm solution, but power was reduced if a PVA or wipe separator was used in higher conductivity solutions with either Pt or activated carbon catalysts. Spray and cast PVA separators performed similarly, but the spray method is preferred as it was easier to apply and use.

  14. Processing of irradiated, enriched uranium fuels at the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hyder, M L; Perkins, W C; Thompson, M C; Burney, G A; Russell, E R; Holcomb, H P; Landon, L F

    1979-04-01

    Uranium fuels containing /sup 235/U at enrichments from 1.1% to 94% are processed and recovered, along with neptunium and plutonium byproducts. The fuels to be processed are dissolved in nitric acid. Aluminum-clad fuels are disssolved using a mercury catalyst to give a solution rich in aluminum. Fuels clad in more resistant materials are dissolved in an electrolytic dissolver. The resulting solutions are subjected to head-end treatment, including clarification and adjustment of acid and uranium concentration before being fed to solvent extraction. Uranium, neptunium, and plutonium are separated from fission products and from one another by multistage countercurrent solvent extraction with dilute tri-n-butyl phosphate in kerosene. Nitric acid is used as the salting agent in addition to aluminum or other metal nitrates present in the feed solution. Nuclear safety is maintained through conservative process design and the use of monitoring devices as secondary controls. The enriched uranium is recovered as a dilute solution and shipped off-site for further processing. Neptunium is concentrated and sent to HB-Line for recovery from solution. The relatively small quantities of plutonium present are normally discarded in aqueous waste, unless the content of /sup 238/Pu is high enough to make its recovery desirable. Most of the /sup 238/Pu can be recovered by batch extraction of the waste solution, purified by counter-current solvent extraction, and converted to oxide in HB-Line. By modifying the flowsheet, /sup 239/Pu can be recovered from low-enriched uranium in the extraction cycle; neptunium is then not recovered. The solvent is subjected to an alkaline wash before reuse to remove degraded solvent and fission products. The aqueous waste is concentrated and partially deacidified by evaporation before being neutralized and sent to the waste tanks; nitric acid from the overheads is recovered for reuse.

  15. Efficacy of a Solution-Based Approach for Making Sodalite Waste Forms for an Oxide Reduction Salt Utilized in the Reprocessing of Used Uranium Oxide Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Pierce, David A.; Frank, Steven M.; Matyas, Josef; Burns, Carolyn A.

    2015-04-01

    This paper describes various approaches for making sodalite with a LiCl-Li2O oxide reduction salt used to recover uranium from used oxide fuel. The approaches include sol-gel and solution-based synthesis processes. As-made products were mixed with 5 and 10 mass% of a Na2O-B2O3-SiO2 glass binder and these, along with product without a binder, were heated using either a cold-press-and-sinter method or hot uniaxial pressing. The results demonstrate the limitation of sodalite yield due to the fast intermediate reactions between Na+ and Cl- to form halite in solution and Li2O and SiO2 to form lithium silicates (e.g., Li2SiO3 or Li2Si2O5) in the calcined and sintered pellets. The results show that pellets can be made with high sodalite fractions (~92 mass%) and low porosities using a solution-based approach and this LiCl-Li2O salt.

  16. Effect of fuels on conductivity, dielectric and humidity sensing properties of ZrO2 nanocrystals prepared by low temperature solution combustion method

    Directory of Open Access Journals (Sweden)

    H.C. Madhusudhana

    2016-09-01

    Full Text Available ZrO2 nanopowders were synthesized by low temperature solution combustion method using two different fuels namely glycine and oxalyldihydrazide (ODH. The phase confirmation was done by powder X-ray diffraction (PXRD and Raman spectral analysis. Use of glycine resulted in ZrO2 with mixture of tetragonal and monoclinic phase with average crystallite size of ∼30 nm. However, ODH as fuel aids in the formation of ZrO2 with mixture of tetragonal and cubic phase with average crystallite size ∼20 nm. Further, in present work we present novel way to tune conductivity property of the nano ZrO2. We show that merely changing the fuel from glycine to ODH, we obtain better DC conductivity and dielectric constant. On the other hand use of glycine leads to the formation of ZrO2 with better AC conductivity and humidity sensing behavior. The dielectric constants calculated for samples prepared with glycine and ODH were found to be 45 and 26 respectively at 10 MHz. The AC and DC conductivity values of the samples prepared with glycine was found to be 9.5 × 10−4 S cm−1, 1.1 × 10−3 S cm−1 and that of ODH was 7.6 × 10−4 S cm−1, 3.6 × 10−3 S cm−1 respectively.

  17. Modeling Solute Thermokinetics in LiCI-KCI Molten Salt for Nuclear Waste Separation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Dane; Eapen, Jacob

    2013-10-01

    Recovery of actinides is an integral part of a closed nuclear fuel cycle. Pyrometallurgical nuclear fuel recycling processes have been developed in the past for recovering actinides from spent metallic and nitride fuels. The process is essentially to dissolve the spent fuel in a molten salt and then extract just the actinides for reuse in a reactor. Extraction is typically done through electrorefining, which involves electrochemical reduction of the dissolved actinides and plating onto a cathode. Knowledge of a number of basic thermokinetic properties of salts and salt-fuel mixtures is necessary for optimizing present and developing new approaches for pyrometallurgical waste processing. The properties of salt-fuel mixtures are presently being studied, but there are so many solutes and varying concentrations that direct experimental investigation is prohibitively time consuming and expensive (particularly for radioactive elements like Pu). Therefore, there is a need to reduce the number of required experiments through modeling of salt and salt-fuel mixture properties. This project will develop first-principles-based molecular modeling and simulation approaches to predict fundamental thermokinetic properties of dissolved actinides and fission products in molten salts. The focus of the proposed work is on property changes with higher concentrations (up to 5 mol%) of dissolved fuel components, where there is still very limited experimental data. The properties predicted with the modeling will be density, which is used to assess the amount of dissolved material in the salt; diffusion coefficients, which can control rates of material transport during separation; and solute activity, which determines total solubility and reduction potentials used during electrorefining. The work will focus on La, Sr, and U, which are chosen to include the important distinct categories of lanthanides, alkali earths, and actinides, respectively. Studies will be performed using LiCl-KCl salt

  18. Analysis on Fueling Abnormally by Pressure of x Airplane and its Solutions%某型飞机压力加油不正常故障分析及解决方案

    Institute of Scientific and Technical Information of China (English)

    范吉林

    2012-01-01

    Through the analysis of the reason that fuel tanks of NoBE180, NoBE181 of X airplane fuel abnormally by pressure, the paper puts forward the corresponding solutions. The practice verifies that these solutions can clear up this kind of breakdown.%通过对某型飞机BE180、BE181前组油箱压力加油不正常故障的原因的分析。提出了相应的解决方案,这些解决方案可以排除此类故障。

  19. MOUTH DISSOLVING TABLETS: A FUTURE COMPACTION

    Directory of Open Access Journals (Sweden)

    Srivastava Saurabh

    2012-08-01

    Full Text Available An orally disintegrating tablet or mouth dissolving tablet (MDT is a drug dosage form available for a limited amount of over-the-counter (OTC and prescription medications. MDTs differ from traditional tablets in that they are designed to be dissolved on the tongue rather than swallowed whole. A variety of pharmaceutical research has been conducted to develop new dosage forms. Among the dosage forms developed to facilitate ease of medication, the mouth dissolving tablet (MDT is one of the most widely employed commercial products. As our society is becoming increasingly aged, the development of mouth dissolving tablets have been formulated for pediatric, geriatric, and bedridden patients and for active patients who are busy and travelling and may not have access to water. Such formulations provide an opportunity for product line extension in the many elderly persons will have difficulties in taking conventional oral dosage forms (viz., solutions, suspensions, tablets, and capsules because of hand tremors and dysphagia. Oral delivery is currently the gold standard in the pharmaceutical industry where it is regarded as the safest, most convenient and most economical method of drug delivery having the highest patient compliance. Recent development in fast disintegrating technology mainly works to improve the disintegration quality of these delicate dosage forms without affecting their integrity. This article focuses on the patented technologies available and the advances made so far in the field of fabrication of mouth dissolving tablets. Apart from the conventional methods of fabrication, this review also provides the detailed concept of some unique technologies like freeze drying, direct compression, spray drying, tablet molding, sublimation, fast dissolving films cotton candy process, along with their advantages and limitations.

  20. Studies of dissolution solutions of ruthenium metal, oxide and mixed compounds in nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mousset, F.; Eysseric, C.; Bedioui, F

    2004-07-01

    Ruthenium is one of the fission products generated by irradiated nuclear fuel. It is present throughout all the steps of nuclear fuel reprocessing-particularly during extraction-and requires special attention due to its complex chemistry and high {beta}{gamma} activity. An innovative electro-volatilization process is now being developed to take advantage of the volatility of RuO{sub 4} in order to eliminate it at the head end of the Purex process and thus reduce the number of extraction cycles. Although the process operates successfully with synthetic nitrato-RuNO{sup 3+} solutions, difficulties have been encountered in extrapolating it to real-like dissolution solutions. In order to better approximate the chemical forms of ruthenium found in fuel dissolution solutions, kinetic and speciation studies on dissolved species were undertaken with RuO{sub 2},xH{sub 2}O and Ru{sup 0} in nitric acid media. (authors)

  1. Understanding Your Watershed Fact Sheet: Dissolved Oxygen

    OpenAIRE

    Mesner, Nancy; Geiger, John

    2010-01-01

    Dissolved oxygen describes oxygen molecules which have actually dissolved in water. Sometimes people confuse bubbles in water with dissolved oxygen, but in reality the dissolved form of oxygen cannot be seen.

  2. Effect of Greenhouse Gases Dissolved in Seawater

    Directory of Open Access Journals (Sweden)

    Shigeki Matsunaga

    2015-12-01

    Full Text Available A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region.

  3. Atomic Layer Deposition from Dissolved Precursors.

    Science.gov (United States)

    Wu, Yanlin; Döhler, Dirk; Barr, Maïssa; Oks, Elina; Wolf, Marc; Santinacci, Lionel; Bachmann, Julien

    2015-10-14

    We establish a novel thin film deposition technique by transferring the principles of atomic layer deposition (ALD) known with gaseous precursors toward precursors dissolved in a liquid. An established ALD reaction behaves similarly when performed from solutions. "Solution ALD" (sALD) can coat deep pores in a conformal manner. sALD offers novel opportunities by overcoming the need for volatile and thermally robust precursors. We establish a MgO sALD procedure based on the hydrolysis of a Grignard reagent.

  4. Effects of Catholyte and Dissolved Oxygen on Microbial Fuel Cell Performance%阴极液及溶氧对微生物燃料电池性能的影响

    Institute of Scientific and Technical Information of China (English)

    樊立萍; 郑钰姣; 苗晓慧

    2016-01-01

    研究微生物燃料电池在几种不同阴极液和曝气条件下处理餐饮废水及同步发电的性能。分别对以NaCl、K 3[Fe(CN)6]和NaCl+K 3[Fe(CN)6]三种溶液为阴极液的微生物燃料电池进行了实验运行,对比分析了其产电性能和净水效果;对阴极室曝气和自然复氧两种条件下微生物燃料电池整体性能进行了对比研究。实验结果表明,阴极液和曝气条件的变化会影响微生物燃料电池的发电性能和净水效果。在以NaCl+K3[Fe(CN)6]混合液为阴极液且阴极室曝气的条件下,以餐饮废水为底物的微生物燃料电池的废水处理效果和产电能力最佳,相应的食堂原废水的产电电流密度稳态值为8.7 mA⋅m−2,COD去除率为46.2%;模拟废水的产电电流密度稳态值为6.84 mA⋅m−2,COD去除率为33.1%。选择合适的阴极液和曝气状态,微生物燃料电池可有效处理餐饮废水并取得良好的发电性能。%Microbial fuel cells with several different catholytes and aeration conditions were used in restaurant wastewater treatment and simultaneous power generation. NaCl, K3[Fe(CN)6] and NaCl+K3[Fe(CN)6] were selected as the catholyte, and the electricity generation and water purification performance of the microbial fuel cell were compared. Furthermore, comparative experiments of the microbial fuel cell under different aeration conditions were also studied. Experimental results show that variation of catholytes and aeration conditions can affect power generation and water purification performance of the microbial fuel cell, which shows best performance when the catholyte is NaCl+K3[Fe(CN)6] and the cathode chamber keeps aeration. The corresponding steady current density of the raw restaurant wastewater is 8.7 mA⋅m−2 and COD removal efficiency is 46.2%. The steady current density and COD removal efficiency for the simulated wastewater is 6.84 mA⋅m−2 and 33.1%, respectively. Under appropriate

  5. Biological processes for environmental control of effluent streams in the nuclear fuel cycle. [Denitrification; removal of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Shumate, II, S E; Hancher, C W; Strandberg, G W; Scott, C D

    1978-01-01

    Nitrates and radioactive heavy metals need to be removed from aqueous effluent streams in the fuel cycle. Biological methods are being developed for reducing nitrate or nitrite to N/sub 2/ gas and for decreasing dissolved metal concentration to less than 1 g/m/sup 3/. Fluidized-bed denitrification bioreactors are being tested. Removal of uranium from solution by Saccharomyces cerevisiae and Pseudomonas aeruginosa was studied. (DLC)

  6. A multiphase interfacial model for the dissolution of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jerden, James L., E-mail: jerden@anl.gov [Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL 60439 (United States); Frey, Kurt [University of Notre Dame, Notre Dame, IN 46556 (United States); Ebert, William [Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL 60439 (United States)

    2015-07-15

    Highlights: • This model accounts for chemistry, temperature, radiolysis, U(VI) minerals, and hydrogen effect. • The hydrogen effect dominates processes determining spent fuel dissolution rate. • The hydrogen effect protects uranium oxide spent fuel from oxidative dissolution. - Abstract: The Fuel Matrix Dissolution Model (FMDM) is an electrochemical reaction/diffusion model for the dissolution of spent uranium oxide fuel. The model was developed to provide radionuclide source terms for use in performance assessment calculations for various types of geologic repositories. It is based on mixed potential theory and consists of a two-phase fuel surface made up of UO{sub 2} and a noble metal bearing fission product phase in contact with groundwater. The corrosion potential at the surface of the dissolving fuel is calculated by balancing cathodic and anodic reactions occurring at the solution interfaces with UO{sub 2} and NMP surfaces. Dissolved oxygen and hydrogen peroxide generated by radiolysis of the groundwater are the major oxidizing agents that promote fuel dissolution. Several reactions occurring on noble metal alloy surfaces are electrically coupled to the UO{sub 2} and can catalyze or inhibit oxidative dissolution of the fuel. The most important of these is the oxidation of hydrogen, which counteracts the effects of oxidants (primarily H{sub 2}O{sub 2} and O{sub 2}). Inclusion of this reaction greatly decreases the oxidation of U(IV) and slows fuel dissolution significantly. In addition to radiolytic hydrogen, large quantities of hydrogen can be produced by the anoxic corrosion of steel structures within and near the fuel waste package. The model accurately predicts key experimental trends seen in literature data, the most important being the dramatic depression of the fuel dissolution rate by the presence of dissolved hydrogen at even relatively low concentrations (e.g., less than 1 mM). This hydrogen effect counteracts oxidation reactions and can limit

  7. Mass transfer in fuel cells

    Science.gov (United States)

    Walker, R. D., Jr.

    1973-01-01

    Developments in the following areas are reported: surface area and pore size distribution in electrolyte matrices, electron microscopy of electrolyte matrices, surface tension of KOH solutions, water transport in fuel cells, and effectiveness factors for fuel cell components.

  8. Compositions and methods for treating nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z; Johnsen, Amanda M; McNamara, Bruce K; Hanson, Brady D; Smith, Steven C; Peper, Shane M

    2014-01-28

    Compositions are provided that include nuclear fuel. Methods for treating nuclear fuel are provided which can include exposing the fuel to a carbonate-peroxide solution. Methods can also include exposing the fuel to an ammonium solution. Methods for acquiring molybdenum from a uranium comprising material are provided.

  9. Compositions and methods for treating nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z; Johnsen, Amanda M; McNamara, Bruce K; Hanson, Brady D; Smith, Steven C; Peper, Shane M

    2013-08-13

    Compositions are provided that include nuclear fuel. Methods for treating nuclear fuel are provided which can include exposing the fuel to a carbonate-peroxide solution. Methods can also include exposing the fuel to an ammonium solution. Methods for acquiring molybdenum from a uranium comprising material are provided.

  10. Contribution to Conversion of CO2 to fuel by electro-photo-catalytic reduction in hydro-genocarbonated aqueous solution tion

    Science.gov (United States)

    Nezzal, Ghania; Benammar, Souad; Hamouni, Samia; Meziane, Dalila; Naama, Sabrina; Abdessemed, Djamel

    2015-04-01

    Referring to the last World Conference COPENHAGEN (2010), endorsed by the United Nations,to '' RISKS OF CLIMATE CHANGES ', states had not reached an agreement to work fairly, in an international program, to limit Carbon dioxide emissions into the atmosphere, to put off it, to the next (in 2015), the right decisions, despite the recommendations of the 'IPCC'. Based on the natural reaction of photosynthesis, which converts carbon dioxide in the presence of water and sun, to '' OSA'' ', it is natural that scientists believe to implement an artificial conversion of CO2 in a renewable energy faster. Our contribution focuses on the same goals, by a different line. In this perspective, nano-materials, catalysts, pervaporation membranes, pervaporation unit, and a photo-reactor prototype, have been made. A summary of the preliminary results presented: For example, are given the concentrations of the various species present in a aqueous solution of sodium hydrogen carbonate, 0.5M, saturated with CO2, at standard temperature and pressure: (CO2) = 1M; (H2CO3) = 0,038M; (HCO3-) = 0,336M; (CO3 --) = 0,34M; pH = 7.33, an overall concentration = 1,714M, more than three times that of the initial solution. It is in such conditions that the conversion of carbon dioxide by the hydrogen produced in situ by electrolysis, in fuel, must be done in the presence of catalyst, under UV radiation. For electrodes, a nano-porous layer was formed on their surface to receive the suitable catalyst. These lats prepared, are made of porous supports (montmorillonite, aluminum and silicon oxides) into which are inserted the metal precursor, by impregnation interactive, in Iron, cobalt, nickel salt solutions, cobalt, nickel. Their performance has been identified by the reduction of para- nitrophenol, to para-aminophenol in aqueous medium in the presence of sodium borohydride. This is the catalyst 'Cobalt supported by SiO2'' that gave the best conversion, 99.5% instead of 99.7%, for a platinum catalyst

  11. Photoluminescent Detection of Dissolved Underwater Trace Explosives

    Directory of Open Access Journals (Sweden)

    Tye Langston

    2010-01-01

    Full Text Available A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial components by directly injecting the reagents into a continually flowing seawater stream using a small amount of organic solvent (approximately 8% of the total solution. Europium's vulnerability to vibrational fluorescence quenching by water provided the mode of detection. Without nitroglycerin in the seawater solution, the reagent's fluorescence was quenched, but when dissolved nitroglycerin was present, it displaced the water molecules from the europium/thenoyltrifluoroacetone compound and restored fluorescence. This effort focused on developing a seawater sensor, but performance comparisons were made to freshwater. The method was found to perform better in freshwater and it was shown that certain seawater constituents (such as calcium have an adverse impact. However, the concentrations of these constituents are not expected to vary significantly from the natural seawater used herein.

  12. Water reactive hydrogen fuel cell power system

    Science.gov (United States)

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  13. Water reactive hydrogen fuel cell power system

    Science.gov (United States)

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-11-25

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  14. Solution-chemical route to generalized synthesis of metal germanate nanowires with room-temperature, light-driven hydrogenation activity of CO2 into renewable hydrocarbon fuels.

    Science.gov (United States)

    Liu, Qi; Zhou, Yong; Tu, Wenguang; Yan, Shicheng; Zou, Zhigang

    2014-01-06

    A facile solution-chemical route was developed for the generalized preparation of a family of highly uniform metal germanate nanowires on a large scale. This route is based on the use of hydrazine monohydrate/H2O as a mixed solvent under solvothermal conditions. Hydrazine has multiple effects on the generation of the nanowires: as an alkali solvent, a coordination agent, and crystal anisotropic growth director. Different-percentage cobalt-doped Cd2Ge2O6 nanowires were also successfully obtained through the addition of Co(OAc)2·4H2O to the initial reaction mixture for future investigation of the magnetic properties of these nanowires. The considerably negative conduction band level of the Cd2Ge2O6 nanowire offers a high driving force for photogenerated electron transfer to CO2 under UV-vis illumination, which facilitates CO2 photocatalytic reduction to a renewable hydrocarbon fuel in the presence of water vapor at room temperature.

  15. Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.

    2013-11-01

    Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 C to improve their performance as oxygen reduction catalysts in neutral pH solutions used in microbial fuel cells (MFCs). The ammonia treated ACs exhibited better catalytic performance in rotating ring-disk electrode tests than their untreated precursors, with the bituminous based AC most improved, with an onset potential of Eonset = 0.12 V (untreated, Eonset = 0.08 V) and n = 3.9 electrons transferred in oxygen reduction (untreated, n = 3.6), and the hardwood based AC (treated, E onset = 0.03 V, n = 3.3; untreated, Eonset = -0.04 V, n = 3.0). Ammonia treatment decreased oxygen content by 29-58%, increased nitrogen content to 1.8 atomic %, and increased the basicity of the bituminous, peat, and hardwood ACs. The treated coal based AC cathodes had higher maximum power densities in MFCs (2450 ± 40 mW m-2) than the other AC cathodes or a Pt/C cathode (2100 ± 1 mW m-2). These results show that reduced oxygen abundance and increased nitrogen functionalities on the AC surface can increase catalytic performance for oxygen reduction in neutral media. © 2013 Elsevier B.V. All rights reserved.

  16. 核燃料溶液系统瞬态特性分析研究%Transient Analysis of Nuclear Fuel Solution System

    Institute of Scientific and Technical Information of China (English)

    于超; 周琦; 朱庆福

    2013-01-01

    在核反应堆乏燃料后处理主工艺流程中,核燃料通常以溶液状态存在,可能发生核临界事故。研究核临界事故的产生机理和事故源项,对预防事故发生、缓解事故后果、事故应急响应与医学诊治均具有十分重要的意义。本文采用点堆动力学方程结合二维热传导方程,开发了基于圆柱形溶液贮存容器的瞬态特性分析程序GETAC ,利用该程序计算了法国SILENE瞬态实验装置模拟临界事故功率随时间的变化,得到了功率振荡在不同反应性引入大小、方式和有无外中子源等情况下的变化规律,计算分析结果与瞬态实验测量数据以及国外其他程序计算结果较一致。%The nuclear fuel exists as solution in the process of spent fuel reprocessing , and it may result in nuclear criticality accident to occur .It is very important to study the mechanism and source term of the criticality accident for preventing accident , consequence mitigation , emergency response and medical diagnostic treatment . A transient analysis code GETAC was developed based on the cylindrical vessel with the point reactor kinetics equation and 2-D thermal conduction equation .Calculation was conducted with this code to simulate the power transient during criticality accident of the SILENE transient experimental facility of France .The power oscillation and its changes under conditions with different values and modes of reactivity insertion ,and with and without external neutron source were obtained .Simulation results are consistent with the transient experimental data and that of other code calculations .

  17. NMR Express-analyser for quality monitoring of motor fuel

    Science.gov (United States)

    Protasov, E. A.; Protasov, D. E.

    2016-09-01

    A method for the rapid analysis of motor fuel quality was developed by artificial increase of the octane number through dissolving ferrocene in a low-octane gasoline (C10H10Fe). Measurements of the spin-lattice relaxation time of nuclear magnetic resonance is used for determination of ferrocene presence in standardized and real fuel from gas stations. The results of measurements of the relaxation characteristics among certain grades of motor fuel with dissolving ferrocene therein are presented.

  18. Natural gas and bio methane in the future fuel mix. Need of action and solution approaches for an accelerated etablishment in the traffic; Erdgas und Biomethan im kuenftigen Kraftstoffmix. Handlungsbedarf und Loesungsansaetze fuer eine beschleunigte Etablierung im Verkehr

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-01-15

    The contribution under consideration reports on the need of action and on solution attempts for an accelerated establishment of natural gas and bio methane in the future fuel mix. The authors come to the following conclusions: The energy situation and climatic situation require a stronger diversification of fuels and drives. The targets for the amount of natural gas and bio methane as a fuel are not reached yet. The characteristics of natural gas speak for an accelerated establishment in the traffic sector. The admixture of bio methane can increase the climatic, environmental and resources advantages. In order to penetrate the market all participants involved must commit themselves to a concrete 'roadmap'. The contribution shows which measures must be converted by the participants involved in order to be able to utilize fully the potentials of the employment of natural gas and bio methane in the traffic sector.

  19. Dissolve energy obesity by energy diet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Heum [Sunmoon University, Asan (Korea)

    2000-07-01

    Every organism takes needed materials or energy from outside and excretes unessential things to outside. This is called a metabolism or energy metabolism. Calculating the amount of energy consumed by human in the world by converting to the amount of metabolism of an animal to survive, the weight of a human being is corresponding to an animal with a weigh of 40 ton. Human beings can find a solution to dissolve energy obesity or can maintain a massive status by finding a new energy source in the universe.

  20. Dissolved organic nitrogen measurement using dialysis pretreatment.

    Science.gov (United States)

    Lee, Wontae; Westerhoff, Paul

    2005-02-01

    Dissolved organic nitrogen (DON) is important for ecological and engineering researches. Quantification of low DON concentrations in waters with elevated dissolved inorganic nitrogen (DIN) using existing methods is inaccurate. In this study, a dialysis-based pretreatment technique was optimized and adopted to reduce the interference from DIN to the quantification of DON in natural water. A cellulose ester dialysis tube (nominal molecular weight cutoff = 100 Da) was used in batch and continuous-flow dialysis steps with model compounds, natural organic matter isolates, and bulk waters to develop a dialysis pretreatment approach that selectively reduces DIN from solutions containing DON. By reducing DIN concentrations, propagation of analytical variance in total dissolved nitrogen (TDN) and DIN species concentrations allows more accurate determination of DON (DON = TDN - NO3 - NO2- - NH3/NH4+). Dialysis for 24 h against continuously flowing distilled water reduced DIN species by 70%. With dialysis pretreatment, DON recoveries of more than 95% were obtained for surface water and finished drinking water, but wastewater experienced a slight loss (approximately 10%) of DON possibly due to the adsorption of organics onto the dialysis membrane, permeation of low molecular weight fractions, or biodegradation. Dialysis experiments using surface water spiked with different DIN/TDN ratios concluded that dialysis pretreatment leads to more accurate DON determination than no dialysis when DIN/TDN ratios exceed 0.6 mg of N/mg of N.

  1. Integrated sampling and analytical approach for common groundwater dissolved gases.

    Science.gov (United States)

    McLeish, Kimberley; Ryan, M Cathryn; Chu, Angus

    2007-12-15

    A novel passive gas diffusion sampler (PGDS) combines sampling, storage and direct injection into a single gas chromatograph (GC). The sampler has a 4.5 mL internal volume when deployed, is easy to operate, and eliminates sample-partitioning. The associated GC method analyzes for a large, dynamic sampling range from a single, small volume injection. Dissolved gases were separated on parallel Rt-Molsieve 5A and Rt-Q-PLOT columns and eluted solutes were quantified using a pulse discharge helium ionization detector (PD-HID). The combined sampling and analytical method appears to be less prone to systematic bias than conventional sampling and headspace partitioning and analysis. Total dissolved gas pressure used in tandem with the PGDS improved the accuracy of dissolved gas concentrations. The incorporation of routine measurements of dissolved biogeochemical and permanent gases into groundwater investigations will provide increased insight into chemical and biological processes in groundwater and improve chemical mass balance accuracy.

  2. Fire Resistant Fuel for Military Compression Ignition Engines

    Science.gov (United States)

    2013-12-04

    fuel (FRF) was a stable mixture of diesel fuel, 10 percent water, and an emulsifier . The Army FRF program ended in 1987 without fielding this fire...was developed. Chemically, this fire resistant fuel (FRF) was a stable mixture of diesel fuel, 10 percent water, and an emulsifier . The Army FRF...diesel fuel, 10% purified water containing less than 50ppm dissolved solids, 6% emulsifier , and 6% aromatic hydrocarbon concentrate to aid in the

  3. Foaming-electrolyte fuel cell

    Science.gov (United States)

    Nanis, L.; Saunders, A. P.

    1970-01-01

    Foam structure feeds fuel gas solution into electrolyte. Fuel gas reacts at static, three-phase interface between fuel gas, electrolyte, and electrode material. The foam forms an electrical contact between main body of electrolyte and the electrode, and aids in removal of by-products of the chemical reaction.

  4. The Measurement of Dissolved Oxygen

    Science.gov (United States)

    Thistlethwayte, D.; And Others

    1974-01-01

    Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)

  5. MOUTH DISSOLVING TABLET: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Kulkarni S. D.

    2011-04-01

    Full Text Available Mouth dissolving Tablets disintegrate and/or dissolve rapidly in the saliva without the need for water. Some tablets are designed to dissolve in saliva extremely fast, within a few seconds, and are true fast-dissolving tablets. Others contain agents to enhance the rate of tablet disintegration in the oral cavity, and are more appropriately termed fast-disintegrating tablets, as they may take up to a minute to completely disintegrate. Mouth or Fast dissolving tablets have been formulated for pediatric, geriatric and bedridden patients and in the many elderly persons will have difficulties in taking conventional oral dosage forms because of hand tremors and dysphagia. The technologies used for manufacturing fast-dissolving tablets are freeze-drying, spray-drying, molding, sublimation, sugar-based excipients, compression, and disintegration addition. As a result of increased life expectancy, the elderly constitute a large portion of the worldwide population today. These people eventually will experience deterioration of their physiological and physical abilities.

  6. Online dissolved methane and total dissolved sulfide measurement in sewers.

    Science.gov (United States)

    Liu, Yiwen; Sharma, Keshab R; Fluggen, Markus; O'Halloran, Kelly; Murthy, Sudhir; Yuan, Zhiguo

    2015-01-01

    Recent studies using short-term manual sampling of sewage followed by off-line laboratory gas chromatography (GC) measurement have shown that a substantial amount of dissolved methane is produced in sewer systems. However, only limited data has been acquired to date due to the low frequency and short span of this method, which cannot capture the dynamic variations of in-sewer dissolved methane concentrations. In this study, a newly developed online measuring device was used to monitor dissolved methane concentrations at the end of a rising main sewer network, over two periods of three weeks each, in summer and early winter, respectively. This device uses an online gas-phase methane sensor to measure methane under equilibrium conditions after being stripped from the sewage. The data are then converted to liquid-phase methane concentrations according to Henry's Law. The detection limit and range are suitable for sewer application and can be adjusted by varying the ratio of liquid-to-gas phase volume settings. The measurement presented good linearity (R² > 0.95) during field application, when compared to off-line measurements. The overall data set showed a wide variation in dissolved methane concentration of 5-15 mg/L in summer and 3.5-12 mg/L in winter, resulting in a significant average daily production of 24.6 and 19.0 kg-CH₄/d, respectively, from the network with a daily average sewage flow of 2840 m³/day. The dissolved methane concentration demonstrated a clear diurnal pattern coinciding with flow and sulfide fluctuation, implying a relationship with the wastewater hydraulic retention time (HRT). The total dissolved sulfide (TDS) concentration in sewers can be determined simultaneously with the same principle.

  7. Pulp-dissolving ability of several endodontic irrigants: a spectrophotometric evaluation.

    Science.gov (United States)

    D'Arcangelo, C; Di Nardo Di Maio, F; Stracci, N; Spoto, G; Malagnino, V A; Caputi, S

    2007-01-01

    The aim of this study is to test the dissolving action of different concentrations of NaOCl (0.5%, 2.5% and 5%) and EDTA 17% on bovine pulp tissue, testing solutions at three different times (1, 5, 10 minutes), 100 mg.of dental pulp placed into a becker with 20 ml of solution was evaluated using a spectrophotometer. A solution of NaOCl 5% showed the highest solubility value. Samples treated with 2.5% NaOCl showed solubility values of 0.98 in one minute, 29.1 in five minutes and 57 in ten minutes. Groups treated with NaOCl 0.5% showed small dissolving modifications. 17% EDTA showed the lowest values of solubility. 5% NaOCl solution showed highest pulp dissolving ability, even a 2.5% solution showed high dissolving ability but in longer times.

  8. Bead and Process for Removing Dissolved Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  9. DIissolution of low enriched uranium from the experimental breeder reactor-II fuel stored at the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Almond, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-28

    The Idaho National Laboratory (INL) is actively engaged in the development of electrochemical processing technology for the treatment of fast reactor fuels using irradiated fuel from the Experimental Breeder Reactor-II (EBR-II) as the primary test material. The research and development (R&D) activities generate a low enriched uranium (LEU) metal product from the electrorefining of the EBR-II fuel and the subsequent consolidation and removal of chloride salts by the cathode processor. The LEU metal ingots from past R&D activities are currently stored at INL awaiting disposition. One potential disposition pathway is the shipment of the ingots to the Savannah River Site (SRS) for dissolution in H-Canyon. Carbon steel cans containing the LEU metal would be loaded into reusable charging bundles in the H-Canyon Crane Maintenance Area and charged to the 6.4D or 6.1D dissolver. The LEU dissolution would be accomplished as the final charge in a dissolver batch (following the dissolution of multiple charges of spent nuclear fuel (SNF)). The solution would then be purified and the 235U enrichment downblended to allow use of the U in commercial reactor fuel. To support this potential disposition path, the Savannah River National Laboratory (SRNL) developed a dissolution flowsheet for the LEU using samples of the material received from INL.

  10. Compton suppressed LaBr{sub 3} detection system for use in nondestructive spent fuel assay

    Energy Technology Data Exchange (ETDEWEB)

    Bender, S., E-mail: BenderESarah@gmail.com; Heidrich, B.; Ünlü, K.

    2015-06-01

    Current methods for safeguarding and accounting for spent nuclear fuel in reprocessing facilities are extremely resource and time intensive. The incorporation of autonomous passive gamma-ray detectors into the procedure could make the process significantly less burdensome. In measured gamma-ray spectra from spent nuclear fuel, the Compton continuum from dominant fission product photopeaks obscure the lower energy lines from other isotopes. The application of Compton suppression to gamma-ray measurements of spent fuel may reduce this effect and allow other less intense, lower energy peaks to be detected, potentially improving the accuracy of multivariate analysis algorithms. Compton suppressed spectroscopic measurements of spent nuclear fuel using HPGe, LaBr{sub 3}, and NaI(Tl) primary detectors were performed. Irradiated fuel was measured in two configurations: as intact fuel elements viewed through a collimator and as feed solutions in a laboratory to simulate the measurement of a dissolved process stream. These two configurations allowed the direct assessment and quantification of the differences in measured gamma-ray spectra from the application of Compton suppression. In the first configuration, several irradiated fuel elements of varying cooling times from the Penn State Breazeale Reactor spent fuel inventory were measured using the three collimated Compton suppression systems. In the second geometry, Compton suppressed measurements of two samples of Approved Test Material commercial fuel elements were recorded inside the guard detector annulus to simulate the siphoning of small quantities from the main process stream for long dwell measurement periods. Compton suppression was found to improve measured gamma-ray spectra of spent fuel for multivariate analysis by notably lowering the Compton continuum from dominant photopeaks such as {sup 137}Cs and {sup 140}La, due to scattered interactions in the detector, which allowed more spectral features to be resolved

  11. Explosives Dissolved from Unexploded Ordnance

    Science.gov (United States)

    2011-10-01

    moisture content) also result in higher corrosion rates especially if the moisture has high dissolved oxygen content ( Manahan 1994). Corrosion of metal is...R. 1993. Handbook of hydrology. New York: McGraw-Hill, Inc. Manahan , S. 1994. Environmental Chemistry. Boca Raton, FL: Lewis Publishers. McCormick

  12. Dissolving pulp from jute stick.

    Science.gov (United States)

    Matin, Mhafuza; Rahaman, M Mostafizur; Nayeem, Jannatun; Sarkar, Mamon; Jahan, M Sarwar

    2015-01-22

    Jute stick is woody portion of jute plant, which remain as leftover after extracting bast fibre. Presently, it is being used for fencing in the rural area. In this investigation, biorefinery concept was initiated in producing dissolving pulp from jute stick by pre-hydrolysis kraft process. At 170°C for 1h of pre-hydrolysis, 70% of hemicelluloses was dissolved with negligible loss of α-cellulose. At this condition, 75% of dissolved sugars in the pre-hydrolysis liquor were in the oligomeric form. The pre-hydrolysed jute stick was subsequently pulped by kraft process with the variation of active alkali. The pulp yield was 36.2% with kappa number 18.5 at the conditions of 16% active alkali for 2h of cooking at 170°C. Final pulp was produced with 92% α-cellulose and 89% brightness after D0EpD1EpD1 bleaching. The produced dissolving pulp can be used in rayon production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Release of dissolved carbohydrates by

    NARCIS (Netherlands)

    Van Oostende, N.; Moerdijk-Poortvliet, T.C.W.; Boschker, H.T.S.; Vyverman, W.; Sabbe, K.

    2013-01-01

    The coccolithophore Emiliania huxleyi plays a pivotal role in the marine carbon cycle. However, we have only limited understanding of how its life cycle and bacterial interactions affect the production and composition of dissolved extracellular organic carbon and its transfer to the particu

  14. Behavior of iodine in the dissolution of spent nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Tsutomu; Komatsu, Kazunori; Takahashi, A. [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

    1997-08-01

    The results of laboratory-scale experiments concerning the behavior of iodine in the dissolution of spent nuclear fuels, which were carried out at the Japan Atomic Energy Research Institute, are summarized. Based on previous and new experimental results, the difference in quantity of residual iodine in the fuel solution between laboratory-scale experiments and reprocessing plants is discussed, Iodine in spent fuels is converted to the following four states: (1) oxidation into I{sub 2} by nitric acid, (2) oxidation into I{sub 2} by nitrous acid generated in the dissolution, (3) formation of a colloid of insoluble iodides such as AgI and PdI{sub 2}, and (4) deposition on insoluble residue. Nitrous acid controls the amount of colloid formed. As a result, up to 10% of iodine in spent fuels is retained in the fuel solution, up to 3% is deposited on insoluble residue, and the balance volatilizes to the off-gas, Contrary to earlier belief, when the dissolution is carried out in 3 to 4 M HNO{sub 3} at 100{degrees}C, the main iodine species in a fuel solution is a colloid, not iodate, Immediately after its formation, the colloid is unstable and decomposes partially in the hot nitric acid solution through the following reaction: AgI(s) + 2HNO{sub 3}(aq) = {1/2}I{sub 2}(aq) + AgNO{sub 3}(aq) + NO{sub 2}(g) + H{sub 2}O(1). For high concentrations of gaseous iodine, I{sub 2}(g), and NO{sub 2}, this reaction is reversed towards formation of the colloid (AgI). Since these concentrations are high near the liquid surface of a plant-scale dissolver, there is a possibility that the colloid is formed there through this reversal, Simulations performed in laboratory-scale experiments demonstrated this reversal, This phenomenon can be one reason the quantity of residual iodine in spent fuels is higher in reprocessing plants than in laboratory-scale experiments. 17 refs., 5 figs., 3 tabs.

  15. Automotive Fuel Processor Development and Demonstration with Fuel Cell Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nuvera Fuel Cells

    2005-04-15

    The potential for fuel cell systems to improve energy efficiency and reduce emissions over conventional power systems has generated significant interest in fuel cell technologies. While fuel cells are being investigated for use in many applications such as stationary power generation and small portable devices, transportation applications present some unique challenges for fuel cell technology. Due to their lower operating temperature and non-brittle materials, most transportation work is focusing on fuel cells using proton exchange membrane (PEM) technology. Since PEM fuel cells are fueled by hydrogen, major obstacles to their widespread use are the lack of an available hydrogen fueling infrastructure and hydrogen's relatively low energy storage density, which leads to a much lower driving range than conventional vehicles. One potential solution to the hydrogen infrastructure and storage density issues is to convert a conventional fuel such as gasoline into hydrogen onboard the vehicle using a fuel processor. Figure 2 shows that gasoline stores roughly 7 times more energy per volume than pressurized hydrogen gas at 700 bar and 4 times more than liquid hydrogen. If integrated properly, the fuel processor/fuel cell system would also be more efficient than traditional engines and would give a fuel economy benefit while hydrogen storage and distribution issues are being investigated. Widespread implementation of fuel processor/fuel cell systems requires improvements in several aspects of the technology, including size, startup time, transient response time, and cost. In addition, the ability to operate on a number of hydrocarbon fuels that are available through the existing infrastructure is a key enabler for commercializing these systems. In this program, Nuvera Fuel Cells collaborated with the Department of Energy (DOE) to develop efficient, low-emission, multi-fuel processors for transportation applications. Nuvera's focus was on (1) developing fuel

  16. Dissolved phosphorus speciation of flash carbonization, slow pyrolysis, and fast pyrolysis biochars

    Science.gov (United States)

    Pyrolysis of waste biomass is a promising technology to produce sterile and renewable organic phosphorus fertilizers. Systematic studies are necessary to understand how different pyrolysis platforms influence the chemical speciation of dissolved (bioavailable) phosphorus. This study employed solut...

  17. Progress on Plant-Level Modeling and Simulation of Used Nuclear Fuel Dissolution: Startup Condition with Quasi-Developed Flow and Varying Acid Concentration

    Energy Technology Data Exchange (ETDEWEB)

    de Almeida, Valmor F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2013-09-20

    An update to a previous report is presented here describing the startup condition of a continuous dissolver. The need for a careful implementation of a startup condition is twofold. First, by varing the used fuel composition and various other parameters of the model, it becomes difficult to solve the governing equations accurately or to obtain a converged solution for an arbitrary initial condition. This is evident when coupling the dissolver module with a third-party user simulator. The second impetus for improving the modeling of the startup process is that an improved realism is obtained and the model is more complete and useful for accounting material balances rigorously. The aforementioned previous report on this dissolver module is a required reading for the understanding of this update.

  18. Behavior of dissolved radiocesium in river water in a forested watershed in Fukushima Prefecture

    Science.gov (United States)

    Tsuji, H.; Nishikiori, T.; Yasutaka, T.; Watanabe, M.; Ito, S.; Hayashi, S.

    2016-10-01

    Dissolved radiocesium concentrations in river water in a high-dose-rate forest watershed in Fukushima Prefecture were investigated under base flow and storm flow conditions. Under base flow conditions, dissolved 137Cs concentrations in water (Bq/L) were relatively high in summer, and these levels were higher than particulate 137Cs concentrations (Bq/L). Under storm flow, particulate 137Cs concentration became dominant as the suspended solid concentration increased. Throughout the monitoring period, dissolved 137Cs concentrations in water (Bq/L) were higher under storm flow than base flow conditions and were positively correlated with runoff intensity. Factors influencing changes in dissolved 137Cs concentrations were investigated by measuring the 137Cs concentration of suspended solid (Bq/kg) and dissolved 137Cs of unsaturated soil water, throughfall, and rainfall, together with other main solute concentrations. The 137Cs concentration per unit weight of suspended solids in river water was not strongly correlated with runoff intensity. Additionally, dissolved 137Cs concentrations of soil water, groundwater, and rainfall were not detected, while higher dissolved 137Cs concentrations were detected in throughfall than river water. K+ concentrations were higher under storm flow than base flow, and dissolved organic carbon increased toward the peak flow rate. These findings suggested that one main factor influencing generation of dissolved 137Cs in the river water was leaching from organic material in flooded areas. However, further investigation is needed to clarify the dominant source of dissolved 137Cs in river water.

  19. Study of Compton suppression for use in spent nuclear fuel assay

    Science.gov (United States)

    Bender, Sarah

    The focus of this study has been to assess Compton suppressed gamma-ray detection systems for the multivariate analysis of spent nuclear fuel. This objective has been achieved using direct measurement of samples of irradiated fuel elements in two geometrical configurations with Compton suppression systems. In order to address the objective to quantify the number of additionally resolvable photopeaks, direct Compton suppressed spectroscopic measurements of spent nuclear fuel in two configurations were performed: as intact fuel elements and as dissolved feed solutions. These measurements directly assessed and quantified the differences in measured gamma-ray spectrum from the application of Compton suppression. Several irradiated fuel elements of varying cooling time from the Penn State Breazeale Reactor spent fuel inventory were measured using three Compton suppression systems that utilized different primary detectors: HPGe, LaBr3, and NaI(Tl). The application of Compton suppression using a LaBr3 primary detector to the measurement of the current core fuel element, which presented the highest count rate, allowed four additional spectral features to be resolved. In comparison, the HPGe-CSS was able to resolve eight additional photopeaks as compared to the standalone HPGe measurement. Measurements with the NaI(Tl) primary detector were unable to resolve any additional peaks, due to its relatively low resolution. Samples of Approved Test Material (ATM) commercial fuel elements were obtained from Pacific Northwest National Laboratory. The samples had been processed using the beginning stages of the PUREX method and represented the unseparated feed solution from a reprocessing facility. Compton suppressed measurements of the ATM fuel samples were recorded inside the guard detector annulus, to simulate the siphoning of small quantities from the main process stream for long dwell measurement periods. Photopeak losses were observed in the measurements of the dissolved ATM

  20. First flush of dissolved compounds

    DEFF Research Database (Denmark)

    Krebs, P.; Holzer, P.; Huisman, J.L.

    1999-01-01

    In a crude conceptual approach it is commonly assumed that in a combined sewer system the concentration of dissolved compounds is diluted by an increasing flow rate due to rainwater inflow. However, theory of hydraulics suggests that these compounds are influenced by hydrodynamic effects....... It is known that since the wave celerity is higher than the flow velocity of the water, the increase of flow rate induced through rain runoff is recognised earlier at a certain downstream section of the combined sewer than the concentration increase of typical rain-water compounds originating from surface...... wash-off. This description implies that the wave front is formed from the fluid that was present in the sewer before the Bow rare increased, that is the sewage! By means of measurements and numerical simulations, it is shown that this effect may cause a significant impact of dissolved compounds...

  1. Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants.

    Science.gov (United States)

    Xiao, Yi-Hua; Huang, Qing-Hui; Vähätalo, Anssi V; Li, Fei-Peng; Chen, Ling

    2014-08-01

    The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM-water partition coefficients (log KOC ) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid-like fluorescent components C1 (excitation/emission=250[313]/412 nm) and C2 (excitation/emission=268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM.

  2. Solution composition and particle size effects on the dissolution and solubility of a ThO{sub 2} microstructural analogue for UO{sub 2} matrix of nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Myllykylae, Emmi; Lavonen, Tiina; Ollila, Kaija [VTT Technical Research Centre of Finland, Espoo (Finland); Stennett, Martin; Corkhill, Claire; Hyatt, Neil [Univ. Sheffield (United Kingdom). Immobilisation Science Lab.

    2015-07-01

    The objective of this study was to investigate the dissolution rate of ThO{sub 2} which was synthesised to approximate, as closely as possible, the microstructure of UO{sub 2} in a nuclear fuel matrix. The optimal sintering temperature for ThO{sub 2} pellets was found to be 1750 C, which produced pellets with a microstructure similar to UO{sub 2} nuclear fuel pellets, with randomly oriented grains ranging in size from 10 to 30 μm. Dissolution was conducted using ThO{sub 2} particles of different size fractions (80 to 160 μm and 2 to 4 mm) in the presence and absence of carbonate, in solutions with pH from 2 to 8 and at 80 C. Dissolution rates were calculated from Th released from the solid phase to solution. Particles of ThO{sub 2} were also leached with 1 M HNO{sub 3} at 80 C in order to investigate the morphological changes at the particle surfaces. The concentration of Th was found to be ≥ 10{sup -9} mol/L at pH ≤ 4, lower than the theoretical solubility of crystalline ThO{sub 2}. At higher pH values, from 4 to 8, the measured concentrations (10{sup -10} to 10{sup -12} mol/L) were between the theoretical solubility of ThO{sub 2} and Th(OH){sub 4}. Grain boundaries were shown to exert an influence on the dissolution of ThO{sub 2} particles. Using high resolution aqueous solution analysis, these data presented here extend the current understanding of Th solubility in solution.

  3. Palm oil and derivatives: fuels or potential fuels?

    OpenAIRE

    Pioch Daniel; Vaitilingom Gilles

    2005-01-01

    Scientific and technical information including field trials about uses of palm oil as fuel has been available for more than half a century now. Several ways were investigated, from the simple mixture with petroleum Diesel fuel, to more sophisticated solutions. The quality of vegetable oils in natura as fuel is difficult to assess because of interferences between properties of the triacylglycerols – the main components – and those of the many minor components, their content varying significant...

  4. Determination of oil/water and octanol/water distribution coefficients from aqueous solutions from four fossil fuels. [MS thesis; in oil-water and octanol-water

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, B.L.

    1984-07-01

    Liquid fossil fuels, both petroleum and synthetically derived oils, are exceedingly complex mixtures of thousands of components. The effect of many of these energy-related components on the environment is largely unknown. Octanol/water distribution coefficients relate both to toxicity and to the bioaccumulation potential of chemical components. Use of these partition data in conjunction with component concentrations in the oils in environmental models provides important information on the fate of fossil fuel components when released to the environment. Octanol/water distribution data are not available for many energy-related organic compounds, and those data that are available have been determined for individual components in simple, one-component octanol/water equilibrium mixtures. In this study, methods for determining many octanol/water distribution coefficients from aqueous extracts of oil products were developed. Sample aqueous mixtures were made by equilibrating liquid fossil fuels with distilled water. This approach has the advantage of detecting interactions between components of interest and other sample components. Compound types studied included phenols, nitrogen bases, hydrocarbons, sulfur heterocyclic compounds, and carboxylic acids. Octanol/water distribution coefficients that were determined in this study ranged from 9.12 for aniline to 67,600 for 1,2-dimethylnaphthalene. Within a compound type, distribution coefficients increased logarithmically with increasing alkyl substitution and molecular weight. Additionally, oil/water distribution data were determined for oil components. These data are useful in predicting maximum environmental concentrations in water columns. 96 references, 26 figures, and 40 tables.

  5. Polygeneration smart grids. A solution for the supply of electricity, potable water and hydrogen as fuel for transportation in remote areas

    Energy Technology Data Exchange (ETDEWEB)

    Kyriakarakos, George; Mohamed, Essam S.; Papadakis, George [Agricultural Univ. of Athens (Greece). Dept. of Natural Resources and Agricultural Engineering

    2010-07-01

    This paper presents the concept of polygeneration smart grids along with experimental results taken during winter 2009-2010 of a pilot polygeneration smart grid focusing on the evolution of the control strategy. In this smart grid the energy of the sun and the wind is harvested by photovoltaic panels and a wind turbine. The system products are electrical energy, potable water through desalination and hydrogen as both medium term energy storage and transportation fuel. Potable water is also used as seasonal energy storage. The components of the system include PV, a wind turbine, batteries, a PEM fuel cell, a PEM electrolyzer, metal hydride tank, hydrogen vehicle refueling subsystem, reverse osmosis desalination unit, data logging system and a control system. Two different controllers have been developed and tested for this smart grid; an ON/OFF controller which operates the electrolyzer, fuel cell and desalination unit at preset points and a fuzzy logic controller which allows for part load operation. The system is installed at the Agricultural University of Athens and the experimental process is ongoing. (orig.)

  6. Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution - A comparison between two different models and experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Eriksen, Trygve E. [School of Chemical Science and Engineering, Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Jonsson, Mats [School of Chemical Science and Engineering, Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm (Sweden)], E-mail: matsj@nuchem.kth.se; Merino, Juan [Enviros Spain S.L., Pg. de Rubi' , 29-31, E-08197 Valldoreix (Spain)

    2008-04-30

    Using two different models, radiation induced dissolution of spent UO{sub 2} fuel has been simulated. One of the models is conventional homogeneous radiolysis simulations where two different geometrical constraints were used and the second model is the recently developed steady-state model. The results of the simulations are compared to each other and to experimental results from spent fuel leaching experiments performed in carbonate containing aqueous solution under Ar-atmosphere. The influence of radiolytically produced H{sub 2} is incorporated (on the basis of a recently suggested mechanism) in both models and this reproduces the experimentally observed inhibition of spent fuel dissolution fairly well. The conventional radiolysis model reproduces the experimental concentrations of the radiolysis products H{sub 2} and O{sub 2} very well while it fails to reproduce the experimental H{sub 2}O{sub 2} concentration. The reasons for this are discussed. The general trend in uranium concentration as a function of time is reproduced by both the conventional radiolysis model and the steady-state model. The conventional radiolysis model (in which the radiation dose is homogeneously distributed in the whole liquid volume) underestimates the uranium concentration while the steady-state model, which represents the worst case scenario, overestimates the concentrations to some extent. When applying the conventional radiolysis model, assuming that all the radiation energy is deposited within 40 {mu}m from the fuel surface, the uranium concentrations during the initial part of the experiments are reproduced quantitatively. The differences between the models and the applicability of the models are discussed in some detail.

  7. Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution A comparison between two different models and experimental data

    Science.gov (United States)

    Eriksen, Trygve E.; Jonsson, Mats; Merino, Juan

    2008-04-01

    Using two different models, radiation induced dissolution of spent UO 2 fuel has been simulated. One of the models is conventional homogeneous radiolysis simulations where two different geometrical constraints were used and the second model is the recently developed steady-state model. The results of the simulations are compared to each other and to experimental results from spent fuel leaching experiments performed in carbonate containing aqueous solution under Ar-atmosphere. The influence of radiolytically produced H 2 is incorporated (on the basis of a recently suggested mechanism) in both models and this reproduces the experimentally observed inhibition of spent fuel dissolution fairly well. The conventional radiolysis model reproduces the experimental concentrations of the radiolysis products H 2 and O 2 very well while it fails to reproduce the experimental H 2O 2 concentration. The reasons for this are discussed. The general trend in uranium concentration as a function of time is reproduced by both the conventional radiolysis model and the steady-state model. The conventional radiolysis model (in which the radiation dose is homogeneously distributed in the whole liquid volume) underestimates the uranium concentration while the steady-state model, which represents the worst case scenario, overestimates the concentrations to some extent. When applying the conventional radiolysis model, assuming that all the radiation energy is deposited within 40 μm from the fuel surface, the uranium concentrations during the initial part of the experiments are reproduced quantitatively. The differences between the models and the applicability of the models are discussed in some detail.

  8. PROCESS FOR DISSOLVING BINARY URANIUM-ZIRCONIUM OR ZIRCONIUM-BASE ALLOYS

    Science.gov (United States)

    Jonke, A.A.; Barghusen, J.J.; Levitz, N.M.

    1962-08-14

    A process of dissolving uranium-- zirconium and zircaloy alloys, e.g. jackets of fuel elements, with an anhydrous hydrogen fluoride containing from 10 to 32% by weight of hydrogen chloride at between 400 and 450 deg C., preferably while in contact with a fluidized inert powder, such as calcium fluoride is described. (AEC)

  9. ANALYSIS OF DISSOLVED METHANE, ETHANE, AND ETHYLENE IN GROUND WATER BY A STANDARD GAS CHROMATOGRAPHIC TECHNIQUE

    Science.gov (United States)

    The measurement of dissolved gases such as methane, ethane, and ethylene in ground water is important in determining whether intrinsic bioremediation is occurring in a fuel- or solvent-contaminated aquifer. A simple procedure is described for the collection and subsequent analys...

  10. ANALYSIS OF DISSOLVED METHANE, ETHANE, AND ETHYLENE IN GROUND WATER BY A STANDARD GAS CHROMATOGRAPHIC TECHNIQUE

    Science.gov (United States)

    The measurement of dissolved gases such as methane, ethane, and ethylene in ground water is important in determining whether intrinsic bioremediation is occurring in a fuel- or solvent-contaminated aquifer. A simple procedure is described for the collection and subsequent analys...

  11. Influence of dissolved CO2 on crystallization of epsomite - variation of temperature

    Science.gov (United States)

    Huang, J.; Yin, Q.; Ulrich, J.

    2017-07-01

    Despite the minor amounts of gases dissolved in solutions, they can bring effects on many crystallization systems, which should be regarded as one type of ;invisible; impurity. The evidence of the effect of different dissolved gases on crystallization was provided in previous work. The variation of temperature was taken into consideration in this study. CO2 saturated solutions were prepared and air saturated solutions were used as a comparison. The results indicate that the influence of dissolved CO2 on crystallization of epsomite is altered with the variation of temperature. At low temperature, dissolved CO2 tends to suppress the thermodynamics and kinetic aspects of the solutions. With the increase of temperature the trend is reversed, i.e. at high temperature (>30 °C), dissolved CO2 enhances the relating properties of the solutions. At low temperature, the decrease of the pH value could be the dominating factor. Whereas at high temperature when the dissolved CO2 is in a supersaturated state, it starts to nucleate and grow, and partially changes into nano- or microbubbles, which can attach on crystal surfaces and disturb the crystallization process just as impurities do.

  12. Is Yucca Mountain a long-term solution for disposing of US spent nuclear fuel and high-level radioactive waste?

    Science.gov (United States)

    Thorne, M C

    2012-06-01

    On 26 January 2012, the Blue Ribbon Commission on America's Nuclear Future released a report addressing, amongst other matters, options for the managing and disposal of high-level waste and spent fuel. The Blue Ribbon Commission was not chartered as a siting commission. Accordingly, it did not evaluate Yucca Mountain or any other location as a potential site for the storage or disposal of spent nuclear fuel and high-level waste. Nevertheless, if the Commission's recommendations are followed, it is clear that any future proposals to develop a repository at Yucca Mountain would require an extended period of consultation with local communities, tribes and the State of Nevada. Furthermore, there would be a need to develop generally applicable regulations for disposal of spent fuel and high-level radioactive waste, so that the Yucca Mountain site could be properly compared with alternative sites that would be expected to be identified in the initial phase of the site-selection process. Based on what is now known of the conditions existing at Yucca Mountain and the large number of safety, environmental and legal issues that have been raised in relation to the DOE Licence Application, it is suggested that it would be imprudent to include Yucca Mountain in a list of candidate sites for future evaluation in a consent-based process for site selection. Even if there were a desire at the local, tribal and state levels to act as hosts for such a repository, there would be enormous difficulties in attempting to develop an adequate post-closure safety case for such a facility, and in showing why this unsaturated environment should be preferred over other geological contexts that exist in the USA and that are more akin to those being studied and developed in other countries.

  13. Co-generation of acetylene and hydrogen for a carbide-based fuel system

    Energy Technology Data Exchange (ETDEWEB)

    Carreiro, Louis G.; Burke, A. Alan [Naval Undersea Warfare Center Division Newport, Code 8231, 1176 Howell Street, Newport, RI 02841 (United States); Dubois, Lily [Stonehill College, Department of Chemistry, 320 Washington Street, Easton, MA 02357 (United States)

    2010-09-15

    The co-generation of acetylene and hydrogen from the hydrolysis of calcium carbide and calcium hydride was investigated as part of a unique carbide-based fuel system intended for high-temperature fuel cells. To gain better control of this highly energetic reaction, glycerin was used to coat the reactant particles to form slurry prior to their reaction with water. This process was shown to moderate the rate of gas production, as well as to provide a means for preparing slurry that could be pumped into the reactor vessel. It was also observed that the presence of calcium hydroxide, a by-product of hydrolysis, lowered the solubility of acetylene resulting in a higher initial flow rate due to less acetylene being dissolved in solution. However, the buildup of calcium hydroxide with time inhibited the hydrolysis of both calcium carbide and calcium hydride causing the acetylene and hydrogen flow rates to decrease. (author)

  14. PROCESS OF DISSOLVING ZIRCONIUM ALLOYS

    Science.gov (United States)

    Shor, R.S.; Vogler, S.

    1958-01-21

    A process is described for dissolving binary zirconium-uranium alloys where the uranium content is about 2%. In prior dissolution procedures for these alloys, an oxidizing agent was added to prevent the precipitation of uranium tetrafluoride. In the present method complete dissolution is accomplished without the use of the oxidizing agent by using only the stoichiometric amount or slight excess of HF required by the zirconium. The concentration of the acid may range from 2M to 10M and the dissolution is advatageously carried out at a temperature of 80 deg C.

  15. Distribution of dissolved carbohydrates and uronic acids in a tropical estuary, India

    Indian Academy of Sciences (India)

    Vishwas B Khodse; Narayan B Bhosle; S G Prabhu Matondkar

    2010-08-01

    Carbohydrates including uronic acids are among the active components of dissolved organic carbon, and play an important role in biogeochemical cycling of organic carbon in marine environments. In order to understand their distribution, concentrations of total dissolved carbohydrate (TCHO), dissolved polysaccharide (PCHO), dissolved monosaccharide (MCHO), and dissolved uronic acid (URA) were measured in the Mandovi estuary, west coast of India during the monsoon and premonsoon seasons. The estuary experienced nearly fresh water condition during the monsoon season and marine condition during the pre-monsoon season. Concentrations of TCHO, MCHO and URA ranged from 17.7 to 67.3 M C, 4.1 to 15.5 M C and 2.3 to 10.8 M C, and their contribution to dissolved organic carbon (DOC) varied from ∼11 to 60%, 2.5 to 9.7%, and 1.8 to 5.3%, respectively. PCHO accounted for ∼52 to 92% of the TCHO. Generally, concentrations and yields of TCHO species were greater during the monsoon season. Phytoplankton abundance and bacterial cell numbers influenced the distribution of TCHO in the pre-monsoon season but not during the monsoon season. Transport of TCHO rich (11 to 60%) dissolved organic matter from the Mandovi estuary to the coastal waters during the monsoon season may affect ecosystem function by fueling biological activity of heterotrophic micro-organisms.

  16. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  17. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  18. The First Dissolution of Real Spent Fuel in CRARL

    Institute of Scientific and Technical Information of China (English)

    LIU; Fang; CHANG; Shang-wen; LUO; Fang-xiang; YAN; Tai-hong; HE; Hui; ZHENG; Wei-fang

    2015-01-01

    The dissolution of the spent fuel was accomplished in CRARL under the cooperation among three divisions of department of radiochemistry.The experiment was started in 22September,and was completed in 27September.Two batches spent fuel of xx reactor was dissolved in these 6days.About 13liters feed of the co-decontamination

  19. A New Control and Design of PEM Fuel Cell System Powered Diffused Air Aeration System

    Directory of Open Access Journals (Sweden)

    Ninet M. Ahmed

    2012-06-01

    Full Text Available The goal of aquaculture ponds is to maximize production and profits while holding labor and management efforts to the minimum. Poor water quality in most ponds causes risk of fish kills, disease outbreaks which lead to minimization of pond production. Dissolved Oxygen (DO is considered to be among the most important water quality parameters in fish culture. Fish ponds in aquaculture farms are usually located in remote areas where grid lines are at far distance. Aeration of ponds is required to prevent mortality and to intensify production, especially when feeding is practical, and in warm regions. To increase pond production it is necessary to control dissolved oxygen. Aeration offers the most immediate and practical solution to water quality problems encountered at higher stocking and feeding rates. Many units of aeration system are electrical units so using a continuous, high reliability, affordable, and environmentally friendly power sources is necessary. Fuel cells have become one of the major areas of research in the academia and the industry. Aeration of water by using PEM fuel cell power is not only a new application of the renewable energy, but also, it provides an affordable method to promote biodiversity in stagnant ponds and lakes. This paper presents a new design and control of PEM fuel cell powered a diffused air aeration system for a shrimp farm in Mersa Matruh in Egypt. Also Artificial intelligence (AI control techniques are used to control the fuel cell output power by controlling its input gases flow rate. Moreover the mathematical modeling and simulation of PEM fuel cell is introduced. A comparative study is applied between the performance of fuzzy logic controller (FLC and neural network controller (NNC. The results show the effectiveness of NNC over FLC.

  20. A New Control and Design of PEM Fuel Cell System Powered Diffused Air Aeration System

    Directory of Open Access Journals (Sweden)

    Hassen T. Dorrah

    2012-06-01

    Full Text Available The goal of aquaculture ponds is to maximize production and profits while holding labor and management efforts to the minimum. Poor water quality in most ponds causes risk of fish kills, disease outbreaks which lead to minimization of pond production. Dissolved Oxygen (DO is considered to be among the most important water quality parameters in fish culture. Fish ponds in aquaculture farms are usually located in remote areas where grid lines are at far distance. Aeration of ponds is required to prevent mortality and to intensify production, especially when feeding is practical, and in warm regions. To increase pond production it is necessary to control dissolved oxygen. Aeration offers the most immediate and practical solution to water quality problems encountered at higher stocking and feeding rates. Many units of aeration system are electrical units so using a continuous, high reliability, affordable, and environmentally friendly power sources is necessary. Fuel cells have become one of the major areas of research in the academia and the industry. Aeration of water by using PEM fuel cell power is not only a new application of the renewable energy, but also, it provides an affordable method to promote biodiversity in stagnant ponds and lakes. This paper presents a new design and control of PEM fuel cell powered a diffused air aeration system for a shrimp farm in Mersa Matruh in Egypt. Also Artificial intelligence (AI control techniques are used to control the fuel cell output power by controlling its input gases flow rate. Moreover the mathematical modeling and simulation of PEM fuel cell is introduced. A comparative study is applied between the performance of fuzzy logic controller (FLC and neural network controller (NNC. The results show the effectiveness of NNC over FLC.

  1. Low Temperature Preparation of Ceria Solid Solutions Doubly Doped with Rare-Earth and Alkali-Earth and Their Properties as Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    任引哲; 蒋凯; 王海霞; 孟健; 苏锵

    2003-01-01

    A series of solid electrolytes, (Ce0.8Ln0.2)1-xMxO2-δ (Ln= La, Nd, Sm, Gd, M:Alkali-earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 ℃. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria-based solid electrolyte is improved. The effects of rare-earth and alkali-earth ions on the electricity were discussed. The open-circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce0.8Sm0.2)1-0.05Ca0.05O2-δ as electrolyte are 0.86 V and 33 mW*cm-2, respectively.

  2. Equipment specifications for an electrochemical fuel reprocessing plant

    Energy Technology Data Exchange (ETDEWEB)

    Hemphill, Kevin P [Los Alamos National Laboratory

    2010-01-01

    Electrochemical reprocessing is a technique used to chemically separate and dissolve the components of spent nuclear fuel, in order to produce new metal fuel. There are several different variations to electrochemical reprocessing. These variations are accounted for by both the production of different types of spent nuclear fuel, as well as different states and organizations doing research in the field. For this electrochemical reprocessing plant, the spent fuel will be in the metallurgical form, a product of fast breeder reactors, which are used in many nuclear power plants. The equipment line for this process is divided into two main categories, the fuel refining equipment and the fuel fabrication equipment. The fuel refining equipment is responsible for separating out the plutonium and uranium together, while getting rid of the minor transuranic elements and fission products. The fuel fabrication equipment will then convert this plutonium and uranium mixture into readily usable metal fuel.

  3. Fuel distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tison, R.R.; Baker, N.R.; Blazek, C.F.

    1979-07-01

    Distribution of fuel is considered from a supply point to the secondary conversion sites and ultimate end users. All distribution is intracity with the maximum distance between the supply point and end-use site generally considered to be 15 mi. The fuels discussed are: coal or coal-like solids, methanol, No. 2 fuel oil, No. 6 fuel oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Although the fuel state, i.e., gas, liquid, etc., can have a major impact on the distribution system, the source of these fuels (e.g., naturally-occurring or coal-derived) does not. Single-source, single-termination point and single-source, multi-termination point systems for liquid, gaseous, and solid fuel distribution are considered. Transport modes and the fuels associated with each mode are: by truck - coal, methanol, No. 2 fuel oil, and No. 6 fuel oil; and by pipeline - coal, methane, No. 2 fuel oil, No. 6 oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Data provided for each distribution system include component makeup and initial costs.

  4. Research on recovery of PO~——P from dissolved sludge solution in the form of slow-released fertilizer%以缓释肥形式回收污泥溶解液中PO3-4-p的研究

    Institute of Scientific and Technical Information of China (English)

    王涌; 邱慧琴; 丁国际

    2011-01-01

    The sewage sludge was treated by cell lysis combined with micro-animal predation for sludge reduction. The struvite precipitation method was applied on the dissolved sludge solution so as to recover the PO43- -P in the form of slow-released fertilizer (magnesium ammonium phosphate (MAP)). The effect of pH,Mg/P molar ratio,N/P molar ratio and reaction time on phosphorus recovery was investigated. A pot experiment was conducted to study the fertilizer efficiency of slow-released fertilizer on celtuce. The results showed that the optimum operate conditions were pH 9. 5,molar ratio of Mg : N : P = 1. 8 : 4. 0 : 1. 0 and reacted for 15 min, under these conditions, 93. 0% of PO43--P was recovered from dissolved sludge solution (mass concentration of PO43--P was 50 mg/L). The main component of obtained precipitates was MgNH4 PO4 · 6H2O. The element analytical techniques were applied to analyse the obtained precipitates, it was found that the content of N, P and Mg in the precipitates was quite similar to the theoretical value of those elements in the MAP, while the obtained precipitates contained lower content of heavy metal, so applied the precipitate as fertilizer was safe. Finally,the precipitate was added into soil to test its fertility on celtuce, findings of this experimental study clearly confirmed the addition of precipitate significantly promoted the growth of the test plant,moreover,the fertilizer efficiency of MAP was better than that of commercial fertilizers.%以溶胞—微型动物捕食法进行剩余污泥减量化处理后的富P污泥上清液为研究对象,考察了pH、Mg/P摩尔比(简称Mg/P)、N/P摩尔比(简称N/P)及反应时间等因素对以缓释肥(鸟粪石(MAP))形式回收PO3-4 -P的影响;并以青菜作为供试作物,通过盆栽实验探讨在最优化条件下生成的缓释肥的肥效,并将其与普通化肥的肥效进行了对比.结果表明,对于PO3-4-P质量分数为50 mg/L的污泥上清液,形成MAP

  5. Microbial Fuel Cells for Sulfide Removal

    NARCIS (Netherlands)

    Rabaey, K.; Sompel, van de S.; Maignien, L.; Boon, N.; Aelterman, P.; Clauwaert, P.; Schamphelaire, de L.; The Pham, H.; Vermeulen, J.; Verhaege, M.; Lens, P.N.L.; Verstraete, W.

    2006-01-01

    Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to eleme

  6. DISSOLUTION OF PLUTONIUM METAL USING NITRIC ACID SOLUTIONS CONTAINING POTASSIUM FLUORIDE

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.; Crowder, M.; Bronikowski, M.

    2007-10-15

    The deinventory and deactivation of the Savannah River Site's (SRS's) FB-Line facility required the disposition of approximately 2000 items from the facility's vaults. Plutonium (Pu) scraps and residues which do not meet criteria for conversion to a mixed oxide fuel will be dissolved and the solution stored for subsequent disposition. Some of the items scheduled for dissolution are composite materials containing Pu and tantalum (Ta) metals. The preferred approach for handling this material is to dissolve the Pu metal, rinse the Ta metal with water to remove residual acid, and burn the Ta metal. The use of a 4 M nitric acid (HNO{sub 3}) solution containing 0.2 M potassium fluoride (KF) was initially recommended for the dissolution of approximately 500 g of Pu metal. However, prior to the use of the flowsheet in the SRS facility, a new processing plan was proposed in which the feed to the dissolver could contain up to 1250 g of Pu metal. To evaluate the use of a larger batch size and subsequent issues associated with the precipitation of plutonium-containing solids from the dissolving solution, scaled experiments were performed using Pu metal and samples of the composite material. In the initial experiment, incomplete dissolution of a Pu metal sample demonstrated that a 1250 g batch size was not feasible in the HB-Line dissolver. Approximately 45% of the Pu was solubilized in 4 h. The remaining Pu metal was converted to plutonium oxide (PuO{sub 2}). Based on this work, the dissolution of 500 g of Pu metal using a 4-6 h cycle time was recommended for the HB-Line facility. Three dissolution experiments were subsequently performed using samples of the Pu/Ta composite material to demonstrate conditions which reduced the risk of precipitating a double fluoride salt containing Pu and K from the dissolving solution. In these experiments, the KF concentration was reduced from 0.2 M to either 0.15 or 0.175 M. With the use of 4 M HNO{sub 3} and a reduction in

  7. Fractal kinetic characteristics for dissolving and leaching processes of strontium residue

    Institute of Scientific and Technical Information of China (English)

    XU Longjun; WANG Xingmin; QU Ge; ZHOU Zhengguo; YUE Fenhua

    2010-01-01

    The pore structural characteristics of strontium residue were studied with the N2 adsorption method (ASAP2010). The kinetic properties concerning dissolving and leaching strontium waste were described by determining the concentrations of Sr2+, Ba2+ and soluble sulphides in solutions. The results showed that the specific surface area and pore volume increased with decreasing granule diameter, and the micropore surface of the residue was fractal. In the dissolving and leaching processes of strontium residue, soluble ion concentrations increased with decreasing granule diameter of the residue, and the reaction dimension was lower than the fractal dimension of pore surface. Sr2+ and soluble sulphide concentrations significantly exceeded the defined standard values, while Ba2+ concentrations did not, either in the dissolving or leaching solutions. In addition, dissolving and leaching reactions selectively occurred on the micropore surface of strontium residue.

  8. Effects of dissolved oxygen on electrochemical and semiconductor properties of 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Feng Zhicao [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Cheng Xuequn, E-mail: chxq2000@hotmail.co [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Dong Chaofang; Xu Lin [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Li Xiaogang, E-mail: lixiaogang99@263.ne [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China)

    2010-12-31

    The effects of dissolved oxygen on the electrochemical behavior and semiconductor properties of passive film formed on 316L SS in three solutions with different dissolved oxygen were studied by using polarization curve, Mott-Schottky analysis and the point defect model (PDM). The results show that higher dissolved oxygen accelerates both anodic and cathodic process. Based on Mott-Schottky analysis and PDM, the key parameters for passive film, donor density N{sub d}, flat-band potential E{sub fb} and diffusivity of defects D{sub 0} were calculated. The results display that N{sub d}(1-7 x 10{sup 27}m{sup -3}) and D{sub 0}(1-18 x 10{sup -16}cm{sup 2}/s) increase and E{sub fb} value reduces with the dissolved oxygen in solution.

  9. Dissolved Organic Matter in Freshwaters

    Science.gov (United States)

    Perdue, E. M.; Ritchie, J. D.

    2003-12-01

    Organic matter in freshwaters exists as dissolved molecules, colloids, and particles. It is appropriate to regard these distinctions as dynamic, however, because organic matter can be interconverted readily between these forms by dissolution and precipitation, sorption and desorption, aggregation and disaggregation, etc. Dissolved organic matter (DOM), the subject of this chapter, is defined operationally as the fraction of organic matter in a water sample that passes through a 0.45 μm filter. In the authors' opinion, the scientific literature on organic matter in freshwaters will be better reflected in this review, if data are considered without regard to the manner in which water samples may have been filtered. This more general approach is warranted because: * many submicron colloids and some microorganisms can pass through 0.45 μm filters; * the effective pore size of a 0.45 μm filter is usually unknown, because it is decreased by partial clogging during the filtration of a water sample; * some important studies have been conducted on unfiltered samples or on samples that were filtered through other types of filters; and * some important studies have been conducted on samples that were concentrated with ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) membranes.As methods for fractionation and isolation of organic matter in freshwaters have evolved, and as the intensity of research has waxed and waned in various academic disciplines, a rich and potentially confusing nomenclature has evolved for organic matter in freshwaters. Some of the more commonly encountered descriptors and their associated acronyms, if any, are yellow organic acids (YOAs), aquatic humus, DOM, and natural organic matter (NOM). Regardless of the terminology used in the original literature, the organic matter in freshwaters is referred to as DOM in this review, except when it is necessary to be more specific.

  10. Flowsheet modifications for dissolution of sand, slag, and crucible residues in the F-canyon dissolvers

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.S.; Karraker, D.G.; Graham, F.R.

    1997-12-01

    An initial flowsheet for the dissolution of sand, slag, and crucible (SS{ampersand}C) was developed for the F- Canyon dissolvers as an alternative to dissolution in FB-Line. In that flowsheet, the sand fines were separated from the slag chunks and crucible fragments. Those two SS{ampersand}C streams were packaged separately in mild-steel cans for dissolution in the 6.4D dissolver. Nuclear safety constraints limited the dissolver charge to approximately 350 grams of plutonium in two of the three wells of the dissolver insert and required 0.23M (molar) boron as a soluble neutron poison in the 9.3M nitric acid/0.013M fluoride dissolver solution. During the first dissolution of SS{ampersand}C fines, it became apparent that a significant amount of the plutonium charged to the 6.4D dissolver did not dissolve in the time predicted by previous laboratory experiments. The extended dissolution time was attributed to fluoride complexation by boron. An extensive research and development (R{ampersand}D) program was initiated to investigate the dissolution chemistry and the physical configuration of the dissolver insert to understand what flowsheet modifications were needed to achieve a viable dissolution process.

  11. Fast dissolving strips: A novel approach for the delivery of verapamil

    OpenAIRE

    Kunte, S.; P Tandale

    2010-01-01

    Objective: Fast dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules etc. Verapamil is a calcium channel blocker used as an antianginal, antiarrhythmic, and antihypertensive agent with extensive first pass metabolism which results in less bioavailability. This work investigated the possibility of developing verapamil fast dissolving strips allowing fast, reproducible drug dissolution in the oral cavity; thus bypassing first pass...

  12. Critical experiments with mixed oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Harris, D.R. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-06-01

    This paper very briefly outlines technical considerations in performing critical experiments on weapons-grade plutonium mixed oxide fuel assemblies. The experiments proposed would use weapons-grade plutonium and Er{sub 2}O{sub 3} at various dissolved boron levels, and for specific fuel assemblies such as the ABBCE fuel assembly with five large water holes. Technical considerations described include the core, the measurements, safety, security, radiological matters, and licensing. It is concluded that the experiments are feasible at the Rensselaer Polytechnic Institute Reactor Critical Facility. 9 refs.

  13. Solubility of PdI/sub 2/ in nitrate and perchlorate solutions. [For use in spent fuels processing; solvents are water, nitric acid, calcium nitrate, and sodium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Horner, D.E.; Mailen, J.C.; Bigelow, H.R.

    1976-01-01

    This paper reports the solubilities of PdI/sub 2/ as measured in nitric acid by a tracer technique and in water, calcium nitrate, and sodium perchlorate solutions by a specific ion electrode technique. The tracer technique measures all the soluble iodine species, whereas the specific ion electrode measures only simple iodide ions (I/sup -/). When compared on the basis of ionic strength, the values obtained in the nitrate solutions by the two methods were in reasonable agreement. The solubilities in perchlorate solution were much higher than in nitrate, possibly because of ionic equilibria involving Pd/sup 4 +/, but this was not resolved in this work. The activity product constant, K/sub ap(PdI/sub 2/)/ = (2.5 +- 0.4) x 10/sup -23/ (25/sup 0/C), was calculated from PdI/sub 2/ solubility in water. With this value and the standard electrode potentials from the literature, the free energy of formation for PdI/sub 2/ was calculated to be --13.6 kcal/mol.

  14. Nalco Fuel Tech

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, S.

    1995-12-31

    The Nalco Fuel Tech with its seat at Naperville (near Chicago), Illinois, is an engineering company working in the field of technology and equipment for environmental protection. A major portion of NALCO products constitute chemical materials and additives used in environmental protection technologies (waste-water treatment plants, water treatment, fuel modifiers, etc.). Basing in part on the experience, laboratories and RD potential of the mother company, the Nalco Fuel Tech Company developed and implemented in the power industry a series of technologies aimed at the reduction of environment-polluting products of fuel combustion. The engineering solution of Nalco Fuel Tech belong to a new generation of environmental protection techniques developed in the USA. They consist in actions focused on the sources of pollutants, i.e., in upgrading the combustion chambers of power engineering plants, e.g., boilers or communal and/or industrial waste combustion units. The Nalco Fuel Tech development and research group cooperates with leading US investigation and research institutes.

  15. Development of On-Line Spectroscopic pH Monitoring for Nuclear Fuel Reprocessing Plants: Weak Acid Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Amanda J.; Hylden, Laura R.; Campbell, Emily L.; Levitskaia, Tatiana G.; Peterson, James M.; Smith, Frances N.; Bryan, Samuel A.

    2015-05-19

    Knowledge of real-time solution properties and composition is a necessity for any spent nuclear fuel reprocessing method. Metal-ligand speciation in aqueous solutions derived from the dissolved commercial spent fuel is highly dependent upon the acid concentration/pH, which influences extraction efficiency and the resulting speciation in the organic phase. Spectroscopic process monitoring capabilities, incorporated in a counter current centrifugal contactor bank, provide a pathway for on-line real-time measurement of solution pH. The spectroscopic techniques are process-friendly and can be easily configured for on-line applications, while classic potentiometric pH measurements require frequent calibration/maintenance and have poor long-term stability in aggressive chemical and radiation environments. Our research is focused on developing a general method for on-line determination of pH of aqueous solutions through chemometric analysis of Raman spectra. Interpretive quantitative models have been developed and validated under the range of chemical composition and pH using a lactic acid/lactate buffer system. The developed model was applied to spectra obtained on-line during solvent extractions performed in a centrifugal contactor bank. The model predicted the pH within 11% for pH > 2, thus demonstrating that this technique could provide the capability of monitoring pH on-line in applications such as nuclear fuel reprocessing.

  16. Assessment of a metal-organic framework catalyst in air cathode microbial fuel cells over time with different buffers and solutions.

    Science.gov (United States)

    Rossi, Ruggero; Yang, Wulin; Setti, Leonardo; Logan, Bruce E

    2017-06-01

    Metal-organic framework (MOF) on activated carbon (AC) enhanced the performance of cathodes but longevity needs to be considered in the presence of metal chelators or ligands, such as phosphate, present in wastewaters. MOF catalysts on AC initially produced 2.78±0.08Wm(-2), but power decreased by 26% after eight weeks in microbial fuel cells using a 50mM phosphate buffer (PBS) and acetate due to decreased cathode performance. However, power was still 41% larger than that of the control AC (no MOF). Power generation using domestic wastewater was initially 0.73±0.01Wm(-2), and decreased by 21% over time, with power 53% larger than previous reports, although changes in wastewater composition were a factor in performance. Adding phosphate salts to the wastewater did not affect the catalyst performance over time. While MOF catalysts are therefore initially adversely affected by chelators, performance remains enhanced compared to plain AC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Dissolving and melting phenomena of inorganic and organic crystals by addition of third or second components

    Science.gov (United States)

    Funakoshi, Kunio; Negishi, Rina; Nakagawa, Hiroshi; Kawasaki, Rentaro

    2017-06-01

    Dissolution of potassium sulphate (K2SO4) crystals was decelerated or stopped since the trivalent chrome ions (Cr(III)) or the iron ions were added into a K2SO4 aqueous solution, but inhibition mechanism of crystal dissolving by additives is not discussed well. Moreover, the melting inhibition of organic compound crystals by addition of the second components is not reported. In this study, inorganic or organic compound crystals are dissolved in a solution added the third component or were melted in a melt added the second one, and the dissolving and melting inhibition phenomena of the inorganic and organic crystals with additives are discussed. The dissolving rates of K2SO4 crystals decreased with the increasing of the amount of Cr(III) added into an K2SO4 unsaturated solution. The melting rates of m-chloronitrobenzene (CNB) crystals were also decreased by addition of p-CNB. The dissolving rates of a K2SO4 mother crystal and the melting rates of a m-CNB mother crystal were scattered during experiments and the dissolving and the melting phenomena would be caused by adsorption and detachments of additives on and from crystal surfaces.

  18. 加氢裂化装置生产喷气燃料存在问题及解决措施%Problems of producing jet fuel in hydrocracking unit and solutions

    Institute of Scientific and Technical Information of China (English)

    张学佳; 刘国海; 肖勇; 孙宏磊; 张启新

    2012-01-01

    介绍了中国石油天然气股份有限公司大庆石化分公司加氢裂化装置概况及生产状况,分析了装置生产喷气燃料的可行性,把装置生产的煤油分别与3号喷气燃料的国标及公司要求指标对比,发现适当调整煤油馏分的密度、冰点、润滑性及安定性指标就可使其成为合格的喷气燃料.归纳了影响装置产品质量的因素,由大到小依次为:操作条件、原料及产品、添加剂及设备因素.提出一系列的措施:控制好操作条件、稳定原料、改进工艺流程、加入添加剂、加强员工培训及细化管理等,其中严格控制好反应岗位、分馏岗位及制氢岗位的操作条件及平稳操作对生产合格喷气燃料尤为重要.装置生产的喷气燃料已通过了国家认证.%The conditions and production of the hydrocracking unit in the refinery of Daqing Petrochemical Company are introduced, and its feasibility of producing jet fuel is analyzed. The comparison with the requirements of national standard and specifications of Daqing Petrochemical Company for 3 Jet fuel shows that, the present kerosene fractions produced can be used as jet fuel when the density, freezing point, lubricity and stability of kerosene are well adjusted. The factors affecting product quality are given and the order of chief factors influencing jet fuel quality from high to low is listed, i. e. operating conditions, feedstock & products, additive and equipment. A series of relevant countermeasures and solutions are presented such as good control of operating conditions, stabling feedstock, improving process, adding additives, strengthening technical training and detailing management. Three major sections of reaction, fractionation and hydrogen production must have a strict control of operating conditions to maintain a stable operation of the unit which is very important for the production of on-spec jet fuels. The jet fuel produced by the hydrocracking unit meets

  19. Study on the Conversion of Fuel Nitrogen Into NOx

    Directory of Open Access Journals (Sweden)

    Raminta Plečkaitienė

    2011-12-01

    Full Text Available The aim of this work is to investigate NOx regularities combusting fuels having high concentration of nitrogen and to develop methods that will reduce the conversion of fuel nitrogen into NOx. There are three solutions to reducing NOx concentration: the combustion of fuel mixing it with other types of “clean” fuel containing small amounts of nitrogen, laundering fuel and the combustion of fuel using carbon additives. These solutions can help with reducing the amount of nitrogen in the wood waste of furniture by about 30% by washing fuel with water. Therefore, NOx value may decrease by about 35%.Article in Lithuanian

  20. Determination of plutonium in spent nuclear fuel using high resolution X-ray

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Kathryn G., E-mail: kmcintosh@lanl.gov; Reilly, Sean D.; Havrilla, George J.

    2015-08-01

    Characterization of Pu is an essential aspect of safeguards operations at nuclear fuel reprocessing facilities. A novel analysis technique called hiRX (high resolution X-ray) has been developed for the direct measurement of Pu in spent nuclear fuel dissolver solutions. hiRX is based on monochromatic wavelength dispersive X-ray fluorescence (MWDXRF), which provides enhanced sensitivity and specificity compared with conventional XRF techniques. A breadboard setup of the hiRX instrument was calibrated using spiked surrogate spent fuel (SSF) standards prepared as dried residues. Samples of actual spent fuel were utilized to evaluate the performance of the hiRX. The direct detection of just 39 ng of Pu is demonstrated. Initial quantitative results, with error of 4–27% and precision of 2% relative standard deviation (RSD), were obtained for spent fuel samples. The limit of detection for Pu (100 s) within an excitation spot of 200 μm diameter was 375 pg. This study demonstrates the potential for the hiRX technique to be utilized for the rapid, accurate, and precise determination of Pu. The results highlight the analytical capability of hiRX for other applications requiring sensitive and selective nondestructive analyses. - Highlights: • Description of high resolution X-ray (hiRX) instrument, based on monochromatic WDXRF • Calibration performed by mapping Pu in dried residues of spiked surrogate spent fuel • Direct, nondestructive determination of Pu in spent nuclear fuel samples • Detection limit of 375 pg Pu in 200 μm excitation spot, 100 s.

  1. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  2. MOUTH DISSOLVING FILM AND THEIR PATENT: AN OVERVIEW

    OpenAIRE

    2012-01-01

    Now days the researchers are focusing on the fast dissolving dosage form (FDDF’s).The fast dissolving dosage forms includes the mouth dissolving tablets, mouth dissolving thin films .The alternative words used for these dosage forms are fast disintegrating, orodispersible, fast dissolving. The oral thin film technology (OTF’s) is a dissolvable film technology have evolved from a purely confectionery novelty from a drug delivery platform. The OTH dosage form dissolves in the moth without nee...

  3. Index analysis and numerical solution of a large scale nonlinear PDAE system describing the dynamical behaviour of molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Chudej, K.; Petzet, V.; Scherdel, S.; Pesch, H.J. [Univ. Bayreuth, Lehrstuhl fuer Ingenieurmathematik (Germany); Heidebrecht, P. [Univ. Magdeburg, Lehrstuhl fuer Systemverfahrenstechnik (Germany); Schittkowski, K. [Univ. Bayreuth, Fachgruppe Informatik (Germany); Sundmacher, K. [Univ. Magdeburg, Lehrstuhl fuer Systemverfahrenstechnik (Germany); Max-Planck-Inst. fuer Dynamik Komplexer Technischer Systeme, Magdeburg (Germany)

    2005-02-01

    This paper deals with the efficient simulation of the dynamical behaviour of molten carbonate fuel cells (MCFCs). MCFCs allow an efficient and environmentally friendly energy production via electrochemical reactions. Their dynamics can be described by large scale systems of up to currently 22 nonlinear partial differential algebraic equations (PDAE). The paper also serves as a basis for later parameter identification and optimal control purposes. Therefore, the numerical simulations are particularly based on hierarchically embedded systems of PDAE, first of all in one space dimension. The PDAE are of mixed parabolic-hyperbolic type and are completed by nonlinear initial and boundary conditions of mixed type. For a series of embedded models in one space dimension, the vertical method of lines (MOL) is used throughout this paper. For the semi-discretization in space appropriate difference schemes are applied depending on the type of equations. The resulting system of ordinary differential algebraic equations (DAE) in time is then solved by a standard RADAU5 method. In order to justify the numerical procedure, a detailed index analysis of the PDAE systems with respect to time index, spatial index and MOL index is carried through. Because of the nonlinearity of the PDAE system, the existing theory has to be generalized. Moreover, MOL is especially suited for near optimal real time control on the basis of a sensitivity analysis of the semi-discretized DAE system, since a theoretically safeguarded sensitivity analysis does not exist so far for PDAE constrained optimal control problems of the above type. Numerical results complete the paper and show their correspondence with the expected dynamical behaviour of MCFCs. (orig.)

  4. Dissolved carbohydrate in the central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Dhople, V.M.; Bhosle, N.B.

    Seawater samples (161), collected from 8 depths (0 to 1000 m) at 21 stations were analysed for total dissolved carbohydrate. Dissolved carbohydrate concentrations varied from 0.072 to 1.15 mg.l-1. Carbohydrate concentrations did not decrease...

  5. Dissolved air flotation and me.

    Science.gov (United States)

    Edzwald, James K

    2010-04-01

    This paper is mainly a critical review of the literature and an assessment of what we know about dissolved air flotation (DAF). A few remarks are made at the outset about the author's personal journey in DAF research, his start and its progression. DAF has been used for several decades in drinking water treatment as an alternative clarification method to sedimentation. DAF is particularly effective in treating reservoir water supplies; those supplies containing algae, natural color or natural organic matter; and those with low mineral turbidity. It is more efficient than sedimentation in removing turbidity and particles for these type supplies. Furthermore, it is more efficient in removing Giardia cysts and Cryptosporidium oocysts. In the last 20 years, fundamental models were developed that provide a basis for understanding the process, optimizing it, and integrating it into water treatment plants. The theories were tested through laboratory and pilot-plant studies. Consequently, there have been trends in which DAF pretreatment has been optimized resulting in better coagulation and a decrease in the size of flocculation tanks. In addition, the hydraulic loading rates have increased reducing the size of DAF processes. While DAF has been used mainly in conventional type water plants, there is now interest in the technology as a pretreatment step in ultrafiltration membrane plants and in desalination reverse osmosis plants. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  6. Alternatives for nuclear fuel disposal

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Badillo A, V.; Palacios H, J.; Celis del Angel, L., E-mail: ramon.ramirez@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2010-10-15

    The spent fuel is one of the most important issues in the nuclear industry, currently spent fuel management is been cause of great amount of research, investments in the construction of repositories or constructing the necessary facilities to reprocess the fuel, and later to recycle the plutonium recovered in thermal reactors. What is the best solution? or, What is the best technology for a specific solution? Many countries have deferred the decision on selecting an option, while other works actively constructing repositories and others implementing the reprocessing facilities to recycle the plutonium obtained from nuclear spent fuel. In Mexico the nuclear power is limited to two reactors BWR type and medium size. So the nuclear spent fuel discharged has been accommodated at reactor's spent fuel pools. Originally these pools have enough capacity to accommodate spent fuel for the 40 years of designed plant operation. However, currently is under process an extended power up rate to 20% of their original power and also there are plans to extend operational life for 20 more years. Under these conditions there will not be enough room for spent fuel in the pools. So this work describes some different alternatives that have been studied in Mexico to define which will be the best alternative to follow. (Author)

  7. Radionuclide release from irradiated Th-Pu mox fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, N.; Quinones, J. [Ciemat., Avda. Complutense 22. E-28040 Madrid (Spain); Cobos, J. [Centro Nacional de Aceleradores, Parque Tecnologico Cartuja 93, Av. Thomas Alva Edison, 7, E-41092 Sevilla (Spain); Rondinella, V.V.; Van Winckel, S.; Somers, J.; Papaioanu, D.; Glatz, J.P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe (Germany)

    2010-07-01

    Plutonium and minor actinides produced as by-products of the UO{sub 2} nuclear cycle could be considered as waste or energy source depending on the strategy selected in the nuclear energy programme. Considering Pu and Minor Actinides as a source, they can be burned in existing water reactor for diminishing the radiotoxicity of the spent fuel, it is necessary to use 'inactive' materials as matrix like ThO{sub 2}. ThO{sub 2} matrix has demonstrated its Pu burning efficiency and higher corrosion resistance than UO{sub 2}. Uranium-plutonium mixed oxide (MOX) fuel efficiency is low because the presence of U in MOX results in the creation of some new Pu under irradiation. The dissolution behaviour of irradiated (Th,Pu)O{sub 2} pellets with burn-up of 38.8 MWd/kg Th has been studied in carbonated (20 mM HCO{sub 3}{sup -}), deionised and granite ground water solution in a hot cell. The dissolution behaviour of Th, Pu, U and Np was studied in order to find out whether radionuclides release is depending on the matrix dissolution (solubility control). After irradiating the samples, K-ORIGEN and ORIGEN ARP codes were used to find out the theoretical inventory. Afterwards, fuel samples were dissolved completely and analyzed, in order to determine the experimental radionuclide inventory of the irradiated fuel. Th matrix alteration appears to reach an steady state and radionuclides dissolution shows dependence on the matrix behaviour as can be observed through the FIAP results. (authors)

  8. Proportioning of {sup 79}Se and {sup 126}Sn long life radionuclides in the fission products solutions coming from spent fuels processing; Dosage des radionucleides a vie longue {sup 79}Se et {sup 126}Sn dans les solutions de produits de fission issues du traitement des combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Comte, J

    2001-11-01

    The determination of radionuclides present in waste resulting from the nuclear fuel reprocessing is a request from the regulatory authorities to ensure an optimal management of the storage sites. Long-lived radionuclides (T{sub 1/2} > 30 years) are particularly concerned owing to the fact that their impact must be considered for the long term. Safety studies have established a list of long-lived radionuclides (LLRN) whose quantification is essential for the management of the disposal site. Among these, several are pure {beta} emitters, present at low concentration levels in complex matrices. Their determination, by radiochemical method or mass spectrometry, involves selective chemical separations from the others {beta}/{gamma} emitters and from the measurement interfering elements. The work undertaken in this thesis relates to the development of analytical methods for the determination of two long-lived radionuclides: selenium 79 and tin 126, in acid solutions of fission products present in nuclear fuel reprocessing plant. For selenium 79, a {beta} emitter with a half live estimated to be 10{sup 6} years, the bibliography describes different chemical separation methods including precipitation, liquid-liquid extraction and chromatography on ionic resins. After optimisation on a synthetic solution, two of these techniques, precipitation by potassium iodine and separation with ion exchange resins were applied to a genuine solution of fission products at Cogema La Hague. The results showed that only the ion exchange method allows us to obtain a solution sufficiently decontaminated (FD{beta}{gamma} = 250) with a significant selenium recovery yield (85%). This separation allows the measurement of the {sup 79}Se by electrothermal vaporization coupled with inductively coupled plasma mass spectrometry (ETV-ICP/MS), after transfer of the samples to CEA/Cadarache. The concentration of {sup 79}Se measured is 0,42 mg/L in the solution of fission products with an isotopic ratio

  9. Evaluation technology for burnup and generated amount of plutonium by measurement of xenon isotopic ratio in dissolver off-gas at reprocessing facility (Joint research)

    OpenAIRE

    岡野 正紀; 久野 剛彦; 高橋 一朗; 白水 秀知; Charlton, W. S.; Wells, C. A.; Hemberger, P. H.; 山田 敬二; 酒井 敏雄

    2006-01-01

    The amount of Pu in the spent fuel was evaluated from Xe isotopic ratio in off-gas in reprocessing facility, is related to burnup. Six batches of dissolver off-gas at spent fuel dissolution process were sampled from the main stack in Tokai Reprocessing Plant during BWR fuel reprocessing campaign. Xenon isotopic ratio was determined with GC/MS. Burnup and generated amount of Pu were evaluated with Noble Gas Environmental Monitoring Application code (NOVA), developed by Los Alamos National Labo...

  10. Aluminum Tape Evaluation for Sealable Aluminum Tubes Containing Mark 22 Fuel Tubes

    Energy Technology Data Exchange (ETDEWEB)

    RHODES, WILLIAM

    2003-01-01

    As part of the HEU Blend Down project, aluminum tape is required to seal aluminum tubes that will hold contaminated Mark 22 fuel tubes for dissolution. From a large field of candidate tapes, Avery Dennison's Fasson 0802 tape (synthetic rubber adhesive system) was found to be acceptable for this application. This tape will disentangle in the normal H-Canyon dissolver solution and have no detrimental effect on the H-Canyon process. Upon placement of Fasson 0802 tape into the dissolver solution, nitric acid will attack and disentangle the block copolymer network and destroy the adhesive nature of the material, resulting in insoluble particles that can be removed via centrifuge operations (cake weight increase of no more than 1 percent). The addition of the tape will not generate off-gas products and the resultant solution characteristics (surface tension, viscosity, density, and disengagement time) will be unaffected. Further, the potential effect on the down-stream evaporation system is negligible. Since the tape will not be placed in a high radiation environment, radiation stability is not an issue. Through detailed discussions with Avery Dennison chemists and based on analytical tests, a fairly detailed understanding of the constituents comprising the proprietary adhesive system has been assembled. Most importantly, chlorine was not detected in the aluminum tape (neutron activation analysis detection limit is 16 ppm). Finally, application of this tape will not impact LEU specifications.

  11. Black Carbon in Marine Dissolved Organic Carbon: Abundance and Radiocarbon Measurements in the Global Ocean

    Science.gov (United States)

    Coppola, A. I.; Walker, B. D.; Druffel, E. R. M.

    2014-12-01

    Compound specific radiocarbon analysis is a powerful tool for understanding the cycling of individual components, such as black carbon (BC) produced from biomass burning and fossil fuel combustion, within bulk pools, like the marine dissolved organic carbon pool. Here, we use a solid phase extraction method and a wide range of solvent polarities to concentrate dissolved organic carbon from seawater. Then we isolate BC in sufficient quantities for radiocarbon analysis. We report the radiocarbon age of BC, concentrations and its relative structure, from coastal and open ocean surface samples. We will discuss our progress towards measuring these quantities in dissolved organic carbon collected from the Pacific and Atlantic oceans to understand the fate, transformation and cycling of BC in the world ocean. These measurements are paired with bulk DOC Δ14C profiles, providing insight into the role of BC as a missing sink in the ultra-refractory DOC pool.

  12. Fabrication of ATALANTE Dissolver Off-Gas Sorbent-Based Capture System

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Jr., Joseph Franklin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-30

    A small sorbent-based capture system was designed that could be placed in the off-gas line from the fuel dissolver in the ATALANTE hot cells with minimal modifications to the ATALANTE dissolver off-gas system. Discussions with personnel from the ATALANTE facility provided guidance that was used for the design. All components for this system have been specified, procured, and received on site at Oak Ridge National Laboratory (ORNL), meeting the April 30, 2015, milestone for completing the fabrication of the ATALANTE dissolver off-gas capture system. This system will be tested at ORNL to verify operation and to ensure that all design requirements for ATALANTE are met. Modifications to the system will be made, as indicated by the testing, before the system is shipped to ATALANTE for installation in the hot cell facility.

  13. A highly accurate method for determination of dissolved oxygen: Gravimetric Winkler method

    Energy Technology Data Exchange (ETDEWEB)

    Helm, Irja; Jalukse, Lauri [University of Tartu, Institute of Chemistry, 14a Ravila str., 50411 Tartu (Estonia); Leito, Ivo, E-mail: ivo.leito@ut.ee [University of Tartu, Institute of Chemistry, 14a Ravila str., 50411 Tartu (Estonia)

    2012-09-05

    Highlights: Black-Right-Pointing-Pointer Probably the most accurate method available for dissolved oxygen concentration measurement was developed. Black-Right-Pointing-Pointer Careful analysis of uncertainty sources was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. Black-Right-Pointing-Pointer This development enables more accurate calibration of dissolved oxygen sensors for routine analysis than has been possible before. - Abstract: A high-accuracy Winkler titration method has been developed for determination of dissolved oxygen concentration. Careful analysis of uncertainty sources relevant to the Winkler method was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. The most important improvements were: gravimetric measurement of all solutions, pre-titration to minimize the effect of iodine volatilization, accurate amperometric end point detection and careful accounting for dissolved oxygen in the reagents. As a result, the developed method is possibly the most accurate method of determination of dissolved oxygen available. Depending on measurement conditions and on the dissolved oxygen concentration the combined standard uncertainties of the method are in the range of 0.012-0.018 mg dm{sup -3} corresponding to the k = 2 expanded uncertainty in the range of 0.023-0.035 mg dm{sup -3} (0.27-0.38%, relative). This development enables more accurate calibration of electrochemical and optical dissolved oxygen sensors for routine analysis than has been possible before.

  14. Hydrogen nanobubbles in a water solution of dietary supplement

    CERN Document Server

    Safonov, Vladimir L

    2013-01-01

    Using gas chromatography, proton nuclear magnetic resonance and qualitative experiments, we demonstrate that a water solution of dissolved dietary supplement, creating negative redox potential, contains invisible hydrogen nano-bubbles, which remain in the solution for several hours.

  15. Reevaluation of JACS code system benchmark analyses of the heterogeneous system. Fuel rods in U+Pu nitric acid solution system

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Tomoyuki; Miyoshi, Yoshinori; Katakura, Jun-ichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    In order to perform accuracy evaluation of the critical calculation by the combination of multi-group constant library MGCL and 3-dimensional Monte Carlo code KENO-IV among critical safety evaluation code system JACS, benchmark calculation was carried out from 1980 in 1982. Some cases where the neutron multiplication factor calculated in the heterogeneous system in it was less than 0.95 were seen. In this report, it re-calculated by considering the cause about the heterogeneous system of the U+Pu nitric acid solution systems containing the neutron poison shown in JAERI-M 9859. The present study has shown that the k{sub eff} value less than 0.95 given in JAERI-M 9859 is caused by the fact that the water reflector below a cylindrical container was not taken into consideration in the KENO-IV calculation model. By taking into the water reflector, the KENO-IV calculation gives a k{sub eff} value greater than 0.95 and a good agreement with the experiment. (author)

  16. Impact of Policy on Fuels RD&D (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Gearhart, C.

    2013-12-01

    This presentation provides an overview of fuel economy and emissions policy and its relationship with fuel research, development, and deployment (RD&D). Solutions explored include biofuels and increased engine efficiency.

  17. Purging dissolved oxygen by nitrogen bubble aeration

    Science.gov (United States)

    Yamashita, Tatsuya; Ando, Keita

    2016-11-01

    We apply aeration with nitrogen microbubbles to water in order to see whether oxygen gas originally dissolved in the water at one atmosphere is purged by the aeration. The concentration of dissolved oxygen (DO) is detected by a commercial DO meter. To detect the dissolved nitrogen (DN) level, we observe the growth of millimetre-sized bubbles nucleated at glass surfaces in contact with the aerated water and compare it with the Epstein-Plesset theory that accounts for DO/DN diffusions and the presence of the glass surfaces. Comparisons between the experiment and the theory suggest that the DO in the water are effectively purged by the aeration.

  18. Measurement and interpretation of low levels of dissolved oxygen in ground water

    Science.gov (United States)

    White, A.F.; Peterson, M.L.; Solbau, R.D.

    1990-01-01

    A Rhodazine-D colorimetric technique was adapted to measure low-level dissolved oxygen concentrations in ground water. Prepared samples containing between 0 and 8.0 ??moles L-1 dissolved oxygen in equilibrium with known gas mixtures produced linear spectrophotometric absorbance with a lower detection limit of 0.2 ??moles L-1. Excellent reproducibility was found for solutions ranging in composition from deionized water to sea water with chemical interferences detected only for easily reduced metal species such as ferric ion, cupric ion, and hexavalent chromium. Such effects were correctable based on parallel reaction stoichiometries relative to oxygen. The technique, coupled with a downhole wire line tool, permitted low-level monitoring of dissolved oxygen in wells at the selenium-contaminated Kesterson Reservoir in California. Results indicated a close association between low but measurable dissolved oxygen concentrations and mobility of oxidized forms of selenium. -from Authors

  19. Linear Active Disturbance Rejection Control of Dissolved Oxygen Concentration Based on Benchmark Simulation Model Number 1

    Directory of Open Access Journals (Sweden)

    Xiaoyi Wang

    2015-01-01

    Full Text Available In wastewater treatment plants (WWTPs, the dissolved oxygen is the key variable to be controlled in bioreactors. In this paper, linear active disturbance rejection control (LADRC is utilized to track the dissolved oxygen concentration based on benchmark simulation model number 1 (BSM1. Optimal LADRC parameters tuning approach for wastewater treatment processes is obtained by analyzing and simulations on BSM1. Moreover, by analyzing the estimation capacity of linear extended state observer (LESO in the control of dissolved oxygen, the parameter range of LESO is acquired, which is a valuable guidance for parameter tuning in simulation and even in practice. The simulation results show that LADRC can overcome the disturbance existing in the control of wastewater and improve the tracking accuracy of dissolved oxygen. LADRC provides another practical solution to the control of WWTPs.

  20. DLA’s Hydrogen Fuel Cell Pilots

    Science.gov (United States)

    2009-05-07

    DLA’s Hydrogen Fuel Cell Pilots E2S2 Conference May 7, 2009 Rob Hardison LMI rhardison@lmi.org Report Documentation Page Form ApprovedOMB No. 0704...2009 to 00-00-2009 4. TITLE AND SUBTITLE DLA’s Hydrogen Fuel Cell Pilots 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...and fuel cells offer potential „green‟ solutions •DLA‟s efforts to measure and improve viability of fuel cells DoD is supporting long term solutions

  1. Fuel cells principles, design, and analysis

    CERN Document Server

    Revankar, Shripad T

    2014-01-01

    ""This book covers all essential themes of fuel cells ranging from fundamentals to applications. It includes key advanced topics important for understanding correctly the underlying multi-science phenomena of fuel cell processes. The book does not only cope with traditional fuel cells but also discusses the future concepts of fuel cells. The book is rich on examples and solutions important for applying the theory into practical use.""-Peter Lund, Aalto University, Helsinki""A good introduction to the range of disciplines needed to design, build and test fuel cells.""-Nigel Brandon, Imperial Co

  2. A study on the radioactive waste management for DUPIC fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Park, H. S.; Park, J. J.; Kim, J. H.; Cho, Y. H.; Shin, J. M.; Kim, Y. K.; Kim, J. S.; Kim, J. G.; Park, S. D.; Suh, M. Y.; Sohn, S. C.; Song, B. C.; Lee, C. H.; Jeon, Y. S.; Jo, K. S.; Jee, K. Y.; Jee, C. S.; Han, S. H.

    1997-09-01

    Part 1: The characteristics if the radioactive wastes coming from the DUPIC fuel manufacturing process were analyzed and evaluated. The gross {alpha}-activity and {alpha}-, {gamma}-spectrum of irradiated zircaloy specimens form KORI unit 1 were analyzed. In order to develop the trapping media of radioactive ruthenium oxides, trapping behavior of volatilized ruthenium oxides on various metal oxides or carbonates was analyzed. Fly ash was selected as a trapping materials for gaseous cesium. And reaction characteristics of CsNO{sub 3} and CsI with fly ash have been investigated. Also, trapping material were performed to test fly ash filter for removal of gaseous cesium under the air and hydrogen atmosphere. The applicability of fly ash to the vitrification of the spent filter was analyzed in the aspects of predictability, leachability. Good quality of Borosilicate glass was formed using Cesium spent filter. Offgas treatment system of DUPIC fuel manufacturing facility was designed and constructed in order to trap of gaseous radioactive waste from 100 batch of OREOXA furnace (the capacity : 500 g/batch). Part II: To develop chemical analysis techniques necessary for understanding chemical properties of the highly radioactive materials related to the development of DUPIC fuel cycle technology, the following basic studies were performed : dissolution of SIMFUEL (simulated fuel), determination of uranium by potentiometry and UV/Vis absorption spectrophotometry, separation of PWR spent fuel, group separation of fission products from uranium, individual separation for analysis of actinides, determination of free acid in a artificial dissolved solution of PWR spent fuel, group separation of fission products form uranium, individual separation of Sm from a mixed rare earth elements and measurement of its isotopes by TI-mass spectrometry, and characteristics of detectors in inductively coupled plasma atomic emission spectrometer (ICP-AES) suitable for analysis of trace fission

  3. Dissolved Trace Metals in the Tay Estuary

    Science.gov (United States)

    Owens, R. E.; Balls, P. W.

    1997-04-01

    Dissolved trace metals have been studied over an annual cycle in the relatively pristine Tay estuary (Scotland). The absence of a major anthropogenic signal has enabled some of the more subtle natural processes controlling trace metal distributions to be identified. Concentration ranges of dissolved metals in the Tay are similar to, or lower than, those observed in more industrialized estuaries. All metals behave non-conservatively in the Tay. Interactions with biogenic and detrital particulate phases are important in controlling dissolved trace metal concentrations. The degradation of organic matter appears to be particularly important for Cu. Removal of dissolved metals was observed in the turbidity maximum zone; a simple model was used to demonstrate that this could be accounted for by adsorption onto suspended particulate matter. At high salinity, coincident peaks of all six metals with ammonia and phosphate are attributed to sewage inputs from Dundee at the mouth of the estuary.

  4. Comparative Emulsifying Properties of Octenyl Succinic Anhydride (OSA)-Modified Starch: Granular Form vs Dissolved State

    Science.gov (United States)

    Marefati, Ali; Gutiérrez, Gemma; Wahlgren, Marie; Rayner, Marilyn

    2016-01-01

    The emulsifying ability of OSA-modified and native starch in the granular form, in the dissolved state and a combination of both was compared. This study aims to understand mixed systems of particles and dissolved starch with respect to what species dominates at droplet interfaces and how stability is affected by addition of one of the species to already formed emulsions. It was possible to create emulsions with OSA-modified starch isolated from Quinoa as sole emulsifier. Similar droplet sizes were obtained with emulsions prepared at 7% (w/w) oil content using OSA-modified starch in the granular form or molecularly dissolved but large differences were observed regarding stability. Pickering emulsions kept their droplet size constant after one month while emulsions formulated with OSA-modified starch dissolved exhibited coalescence. All emulsions stabilized combining OSA-modified starch in granular form and in solution showed larger mean droplet sizes with no significant differences with respect to the order of addition. These emulsions were unstable due to coalescence regarding presence of free oil. Similar results were obtained when emulsions were prepared by combining OSA-modified granules with native starch in solution. The degree of surface coverage of starch granules was much lower in presence of starch in solution which indicates that OSA-starch is more surface active in the dissolved state than in granular form, although it led to unstable systems compared to starch granule stabilized Pickering emulsions, which demonstrated to be extremely stable. PMID:27479315

  5. Fuel cells

    Directory of Open Access Journals (Sweden)

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  6. Future Fuels

    Science.gov (United States)

    2006-04-01

    Storage Devices, Fuel Management, Gasification, Fischer-Tropsch, Syngas , Hubberts’s Peak UNCLAS UNCLAS UNCLAS UU 80 Dr. Sujata Millick (703) 696...prices ever higher, and perhaps lead to intermittent fuel shortages as production fluctuates. Clearly, this competition for resources also provides oil...producers multiple options for selling their products, and raises the possibility that the US could face shortages resulting from shifts in

  7. PREDICTION OF DISSOLVER LIFETIMES THROUGH NON-DESTRUCTIVE EVALUATION AND LABORATORY TESTING

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Woodsmall, T.; Hinz, W.; Edwards, T.

    2011-10-03

    Non-destructive evaluation was used as the primary method of monitoring the corrosion degradation of nuclear material dissolvers and assessing the remaining lifetimes. Materials were typically processed in nitric acid based (4-14M) solutions containing fluoride concentrations less than 0.2 M. The primary corrosion issue for the stainless steel dissolvers is the occurrence of localized corrosion near the tank bottom and the heat affected zones of the welds. Laboratory data for a range of operational conditions, including solution chemistry and temperature, was used to assess the impact of processing changes on the dissolver corrosion rate. Experimental and NDE-based general corrosion rates were found to be in reasonable agreement for standard dissolution chemistries consisting of nitric acid with fluorides and at temperatures less than 95 C. Greater differences were observed when chloride was present as an impurity and temperatures exceeded 100 C.

  8. Dissolved oxygen imaging to investigate biodegradation at lab scale

    Science.gov (United States)

    Lerner, D. N.; Rees, H.; Huang, W. E.; Smith, C. C.; Oswald, S. E.

    2003-04-01

    A novel combination of a non-invasive imaging method with an oxygen sensitive fluorescent indicator was developed to investigate the biodegradation processes occurring at the fringe of a solute plume. A thin transparent porous matrix was made from quartz plates and quartz sand and acetate was continuously injected in the uniform flow field containing dissolved oxygen. Ruthenium (II)-dichlorotris(1,10-phenanthroline) (Ru(phen)3Cl2), a water soluble fluorescent dye, was used as an indicator of dissolved oxygen concentration as its fluorescence intensity is dependent on the concentration of oxygen. The oxygen distribution within the matrix was interpreted from images recorded by a CCD camera. These two-dimensional experimental results show quantitatively how the oxygen concentrations decrease strongly at the narrow plume fringe and that oxygen was exhausted at the core of the plume. Separately, dispersivity was measured in a series of non-reactive transport experiments, and biodegradation parameters were evaluated by batch experiments. This measurement method provides a novel approach to investigate details of behavior of solute transport and biodegradation in porous media.

  9. Transport of dissolved gases through unsaturated porous media

    Science.gov (United States)

    Maryshev, B. S.

    2017-06-01

    The natural porous media (e.g. soil, sand, peat etc.) usually are partially saturated by groundwater. The saturation of soil depends on hydrostatic pressure which is linearly increased with depth. Often some gases (e.g. nitrogen, oxygen, carbon dioxide, methane etc.) are dissolved into the groundwater. The solubility of gases is very small because of that two assumptions is applied: I. The concentration of gas is equal to solubility, II. Solubility depends only on pressure (for isothermal systems). In this way some part of dissolved gas transfers from the solution to the bubble phase. The gas bubbles are immovably trapped in a porous matrix by surface-tension forces and the dominant mechanism of transport of gas mass becomes the diffusion of gas molecules through the liquid. If the value of water content is small then the transport of gas becomes slow and gas accumulates into bubble phase. The presence of bubble phase additionally decreases the water content and slows down the transport. As result the significant mass of gas should be accumulated into the massif of porous media. We derive the transport equations and find the solution which is demonstrated the accumulation of gases. The influence of saturation, porosity and filtration velocity to accumulation process is investigated and discussed.

  10. Thermogravimetric analysis of fuel film evaporation

    Institute of Scientific and Technical Information of China (English)

    HU Zongjie; LI Liguang; YU Shui

    2006-01-01

    Thermogravimetric analysis (TGA) was compared with the petrochemical distillation measurement method to better understand the characteristics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different environmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the internal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantificational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, sufficiently high wall temperature is necessary. Evaporation time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evaporation sequence could not be strictly divided according to the boiling points of each component for multicomponent dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

  11. 缓冲液对微生物燃料电池产电性能影响研究%Influence of Buffer Solutions on the Performance of Microbial Fuel Cell Electricity Generation

    Institute of Scientific and Technical Information of China (English)

    强琳; 袁林江; 丁擎

    2011-01-01

    微生物燃料电池(microbial fuel cell,MFC)应用于废水处理是一项非常有潜力的除污产能的绿色技术.但MFC运行过程中采用磷酸盐缓冲液不符合除污产能要求,增加水体富营养化趋势且增加水处理成本.试验采用单极室微生物燃料电池处理模拟生活污水,以投加PBS(phosphate buffer solution)缓冲液为参比对象,讨论了投加硼砂缓冲液和无缓冲液对产电功率、库仑效率以及出水pH的影响.200 mmol/L的PBS缓冲液电导率为1.973 mS/cm,最大输出功率为36.4 mW/m2,最大库仑效率为2.92%,出水pH为(7.00±0.05).100 mmol/L的硼砂缓冲液的导电率为1.553 mS/cm,输出功率最大26.2 mW/m2,库仑效率为6.26%,是PBS缓冲液库仑效率的2.14倍,显著地提高了电子回收率,出水pH为7.35.无缓冲液电导率为0.314 mS/cm,最大输出功率为27.64 mW/m2,库仑效率为2.82%,出水pH约为7.43.不投加缓冲液的电导率仅为投加PBS缓冲液的1/6,硼砂缓冲液的1/5,功率比PBS低8.76 mW/m2,比硼砂缓冲液高1.24 mW/m2.试验结果表明投加适宜浓度的硼砂缓冲液可大大提高电子回收率,不投加缓冲液MFC在间歇运行模式下可成功运行.%Microbial fuel cell (MFC) is a potential green technology due to its application in wastewater treatment and renewable energy generation. Phosphate buffer solution (PBS) has been commonly used in MFC studies to maintain a suitable pH for electricity generating bacteria and/or to increase the solution conductivity. However, it has some drawbacks using PBS in MFC: One is that the addition of a high concentration of phosphate buffer in MFCs is expensive, especially for the application in wastewater treatment; the other is that phosphates can contribute to the eutrophication conditions of water bodies if the effluents are discharged without the removal of phosphates. By adding PBS buffer as the comparison , the study investigated the effect of borax buffer and in the absence of buffer on

  12. The Role of natural gas and biomethane in the fuel mix of the future in Germany. Required action and potential solutions to accelerate adoption in transport applications; Erdgas und Biomethan im kuenftigen Kraftstoffmix. Handlungsbedarf und Loesungsansaetze fuer eine beschleunigte Etablierung im Verkehr

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-09-15

    The contribution under consideration reports on the need of action and on solution attempts for an accelerated establishment of natural gas and bio methane in the future fuel mix. The authors come to the following conclusions: The energy situation and climatic situation require a stronger diversification of fuels and drives. The targets for the amount of natural gas and bio methane as a fuel are not reached yet. The characteristics of natural gas speak for an accelerated establishment in the traffic sector. The admixture of bio methane can increase the climatic, environmental and resources advantages. In order to penetrate the market all participants involved must commit themselves to a concrete 'roadmap'. The contribution shows which measures must be converted by the participants involved in order to be able to utilize fully the potentials of the employment of natural gas and bio methane in the traffic sector.

  13. Novel materials for fuel cells operating on liquid fuels

    Directory of Open Access Journals (Sweden)

    César A. C. Sequeira

    2017-05-01

    Full Text Available Towards commercialization of fuel cell products in the coming years, the fuel cell systems are being redefined by means of lowering costs of basic elements, such as electrolytes and membranes, electrode and catalyst materials, as well as of increasing power density and long-term stability. Among different kinds of fuel cells, low-temperature polymer electrolyte membrane fuel cells (PEMFCs are of major importance, but their problems related to hydrogen storage and distribution are forcing the development of liquid fuels such as methanol, ethanol, sodium borohydride and ammonia. In respect to hydrogen, methanol is cheaper, easier to handle, transport and store, and has a high theoretical energy density. The second most studied liquid fuel is ethanol, but it is necessary to note that the highest theoretically energy conversion efficiency should be reached in a cell operating on sodium borohydride alkaline solution. It is clear that proper solutions need to be developed, by using novel catalysts, namely nanostructured single phase and composite materials, oxidant enrichment technologies and catalytic activity increasing. In this paper these main directions will be considered.

  14. Effect of dissolved organic carbon in recycled wastewaters on boron adsorption by soils

    Science.gov (United States)

    In areas of water scarcity, recycled municipal wastewaters are being used as water resources for non-potable applications, especially for irrigation. Such wastewaters often contain elevated levels of dissolved organic carbon (DOC) and solution boron (B). Boron adsorption was investigated on eight ...

  15. Complexation with dissolved organic matter and solubility control of heavy metals in sandy soil

    NARCIS (Netherlands)

    Weng, L.; Temminghoff, E.J.M.; Lofts, S.; Tipping, E.; Riemsdijk, van W.H.

    2002-01-01

    The complexation of heavy metals with dissolved organic matter (DOM) in the environment influences the solubility and mobility of these metals. In this paper, we measured the complexation of Cu, Cd, Zn, Ni, and Pb with DOM in the soil solution at pH 3.7-6.1 using a Donnan membrane technique. The res

  16. Methane bioattenuation and implications for explosion risk reduction along the groundwater to soil surface pathway above a plume of dissolved ethanol.

    Science.gov (United States)

    Ma, Jie; Rixey, William G; DeVaull, George E; Stafford, Brent P; Alvarez, Pedro J J

    2012-06-05

    Fuel ethanol releases can stimulate methanogenesis in impacted aquifers, which could pose an explosion risk if methane migrates into enclosed spaces where ignitable conditions exist. To assess this potential risk, a flux chamber was emplaced on a pilot-scale aquifer exposed to continuous release (21 months) of an ethanol solution (10% v:v) that was introduced 22.5 cm below the water table. Despite methane concentrations within the ethanol plume reaching saturated levels (20-23 mg/L), the maximum methane concentration reaching the chamber (21 ppm(v)) was far below the lower explosion limit in air (50,000 ppm(v)). The low concentrations of methane observed in the chamber are attributed to methanotrophic activity, which was highest in the capillary fringe. This was indicated by methane degradation assays in microcosms prepared with soil samples from different depths, as well as by PCR measurements of pmoA, which is a widely used functional gene biomarker for methanotrophs. Simulations with the analytical vapor intrusion model "Biovapor" corroborated the low explosion risk associated with ethanol fuel releases under more generic conditions. Model simulations also indicated that depending on site-specific conditions, methane oxidation in the unsaturated zone could deplete the available oxygen and hinder aerobic benzene biodegradation, thus increasing benzene vapor intrusion potential. Overall, this study shows the importance of methanotrophic activity near the water table to attenuate methane generated from dissolved ethanol plumes and reduce its potential to migrate and accumulate at the surface.

  17. The release of dissolved nutrients and metals from coastal sediments due to resuspension

    Science.gov (United States)

    Kalnejais, Linda H.; Martin, W. R.; Bothner, Michael H.

    2010-01-01

    Coastal sediments in many regions are impacted by high levels of contaminants. Due to a combination of shallow water depths, waves, and currents, these sediments are subject to regular episodes of sediment resuspension. However, the influence of such disturbances on sediment chemistry and the release of solutes is poorly understood. The aim of this study is to quantify the release of dissolved metals (iron, manganese, silver, copper, and lead) and nutrients due to resuspension in Boston Harbor, Massachusetts, USA. Using a laboratory-based erosion chamber, a range of typical shear stresses was applied to fine-grained Harbor sediments and the solute concentration at each shear stress was measured. At low shear stress, below the erosion threshold, limited solutes were released. Beyond the erosion threshold, a release of all solutes, except lead, was observed and the concentrations increased with shear stress. The release was greater than could be accounted for by conservative mixing of porewaters into the overlying water, suggesting that sediment resuspension enhances the release of nutrients and metals to the dissolved phase. To address the long-term fate of resuspended particles, samples from the erosion chamber were maintained in suspension for 90. h. Over this time, 5-7% of the particulate copper and silver was released to the dissolved phase, while manganese was removed from solution. Thus resuspension releases solutes both during erosion events and over a longer timescale due to reactions of suspended particles in the water column. The magnitude of the annual solute release during erosion events was estimated by coupling the erosion chamber results with a record of bottom shear stresses simulated by a hydrodynamic model. The release of dissolved copper, lead, and phosphate due to resuspension is between 2% and 10% of the total (dissolved plus particulate phase) known inputs to Boston Harbor. Sediment resuspension is responsible for transferring a significant

  18. Bio-fuels for the gas turbine: A review

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, K.K. [Mechanical Engineering Department, Medi-Caps Institute of Technology and Management, Pigdamber, Rau, Indore (M.P.) (India); Rehman, A.; Sarviya, R.M. [Department of Mechanical Engineering, MANIT, Bhopal (M.P.) (India)

    2010-12-15

    Due to depletion of fossil fuel, bio-fuels have generated a significant interest as an alternative fuel for the future. The use of bio-fuels to fuel gas turbine seems a viable solution for the problems of decreasing fossil-fuel reserves and environmental concerns. Bio-fuels are alternative fuels, made from renewable sources and having environmental benefit. In recent years, the desire for energy independence, foreseen depletion of nonrenewable fuel resources, fluctuating petroleum fuel costs, the necessity of stimulating agriculture based economy, and the reality of climate change have created an interest in the development of bio-fuels. The application of bio-fuels in automobiles and heating applications is increasing day by day. Therefore the use of these fuels in gas turbines would extend this application to aviation field. The impact of costly petroleum-based aviation fuel on the environment is harmful. So the development of alternative fuels in aviation is important and useful. The use of liquid and gaseous fuels from biomass will help to fulfill the Kyoto targets concerning global warming emissions. In addition, to reduce exhaust emission waste gases and syngas, etc., could be used as a potential gas turbine fuel. The term bio-fuel is referred to alternative fuel which is produced from biomass. Such fuels include bio-diesel, bio-ethanol, bio-methanol, pyrolysis oil, biogas, synthetic gas (dimethyl ether), hydrogen, etc. The bio-ethanol and bio-methanol are petrol additive/substitute. Bio-diesel is an environment friendly alternative liquid fuel for the diesel/aviation fuel. The gas turbine develops steady flame during its combustion; this feature gives a flexibility to use alternative fuels. Therefore so the use of different bio-fuels in gas turbine has been investigated by a good number of researchers. The suitability and modifications in the existing systems are also recommended. (author)

  19. Quivers For Special Fuel Rods-Disposal Of Special Fuel Rods In CASTOR V Casks

    Energy Technology Data Exchange (ETDEWEB)

    Bannani, Amin; Cebula, Wojciech; Buchmuller, Olga; Huggenberg, Roland [GNS, Essen (Germany); Helmut Kuhl [WTI, Julich (Germany)

    2015-05-15

    While GNS casks of the CASTOR family are a suitable means to transfer fuel assemblies (FA) from the NPP to an interim dry storage site, Germanys phase-out of nuclear energy has triggered the demand for an additional solution to dispose of special fuel rods (SFR), normally remaining in the fuel pond until the final shutdown of the NPP. SFR are fuel rods that had to be removed from fuel assemblies mainly due to their special condition, e. g. damages in the cladding of the fuel rods which may have occurred during reactor operations. SFR are usually stored in the spent fuel pond after they are removed from the FA. The quiver for special fuel rods features a robust yet simple design, with a high mechanical stability, a reliable leak-tightness and large safety margins for future requirements on safety analysis. The quiver for special fuel rods can be easily adapted to a large variety of different damaged fuel rods and tailored to the specific need of the customer. The quiver for special fuel rods is adaptable e.g. in length and diameter for use in other types of transport and storage casks and is applicable in other countries as well. The overall concept presented here is a first of its kind solution for the disposal of SFRs via Castor V-casks. This provides an important precondition in achieving the status 'free from nuclear fuel' of the shut down German NPPs.

  20. Effects of cyanide and dissolved oxygen concentration on biological Au recovery.

    Science.gov (United States)

    Kita, Yoshito; Nishikawa, Hiroshi; Takemoto, Tadashi

    2006-07-25

    The number of discarded electric devices containing traces of Au is currently increasing. It is desirable to recover this Au because of its valuable physicochemical properties. Au is usually dissolved with relatively high concentrations of cyanide, which is associated with environmental risk. Chromobacterium violaceum is able to produce and detoxify small amounts of cyanide, and may thus be able to recover Au from discarded electric devices. This study investigated the effects of cyanide and dissolved oxygen concentration on biological Au recovery. Cyanide production by C. violaceum was sufficient to dissolve Au, while maintaining a high cyanide concentration did not enhance Au dissolution. Increased oxygen concentration enhanced Au dissolution from 0.04 to 0.16 mmol/l within the test period of 70 h. Electrochemical measurement clarified this phenomenon; the rest potential of Au in the cyanide solution produced by C. violaceum increased from -400 to -200 mV, while in the sterile cyanide solution, it was constant in cyanide concentrations ranging from 0 to 1.5 mmol/l and increased in dissolved oxygen concentrations ranging from 0 to 0.25 mmol/l. Therefore, it was clarified that dissolved oxygen concentration is the main factor affecting the efficiency of cyanide leaching of gold by using bacteria.

  1. The system architecture for renewable synthetic fuels

    DEFF Research Database (Denmark)

    Ridjan, Iva

    To overcome and eventually eliminate the existing heavy fossil fuels in the transport sector, there is a need for new renewable fuels. This transition could lead to large capital costs for implementing the new solutions and a long time frame for establishing the new infrastructure unless a suitab...

  2. Solar fuels

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, J.R.

    1978-11-17

    The paper is concerned with (1) the thermodynamic and kinetic limits for the photochemical conversion and storage of solar energy as it is received on the earth's surface, and (2) the evaluation of a number of possible photochemical reactions with particular emphasis on the production of solar hydrogen from water. Procedures for generating hydrogen fuel are considered. Topics examined include the general requirements for a fuel-generation reaction, the photochemical reaction, limits on the conversion of light energy to chemical energy, an estimate of chemical storage efficiency, and the water decomposition reaction.

  3. Thermophoresis of dissolved molecules and polymers: Consideration of the temperature-induced macroscopic pressure gradient.

    Science.gov (United States)

    Semenov, Semen; Schimpf, Martin

    2004-01-01

    The movement of molecules and homopolymer chains dissolved in a nonelectrolyte solvent in response to a temperature gradient is considered a consequence of temperature-induced pressure gradients in the solvent layer surrounding the solute molecules. Local pressure gradients are produced by nonuniform London-van der Waals interactions, established by gradients in the concentration (density) of solvent molecules. The density gradient is produced by variations in solvent thermal expansion within the nonuniform temperature field. The resulting expression for the velocity of the solute contains the Hamaker constants for solute-solvent and solute-solute interactions, the radius of the solute molecule, and the viscosity and cubic coefficient of thermal expansion of the solvent. In this paper we consider an additional force that arises from directional asymmetry in the interaction between solvent molecules. In a closed cell, the resulting macroscopic pressure gradient gives rise to a volume force that affects the motion of dissolved solutes. An expression for this macroscopic pressure gradient is derived and the resulting force is incorporated into the expression for the solute velocity. The expression is used to calculate thermodiffusion coefficients for polystyrene in several organic solvents. When these values are compared to those measured in the laboratory, the consistency is better than that found in previous reports, which did not consider the macroscopic pressure gradient that arises in a closed thermodiffusion cell. The model also allows for the movement of solute in either direction, depending on the relative values of the solvent and solute Hamaker constants.

  4. Innovative membrane development for fuel cells

    CSIR Research Space (South Africa)

    Vaivars, G

    2011-10-01

    Full Text Available The innovative membranes for alternative energy devices will be presented. An electrical car is long waited solution to environmental and fuel supply problems in transport. Most probably, the shift from a combustion engine to an electrical car...

  5. Behavior of silicon in nitric media. Application to uranium silicides fuels reprocessing; Comportement du silicium en milieu nitrique. Application au retraitement des combustibles siliciures d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cheroux, L

    2001-07-01

    Uranium silicides are used in some research reactors. Reprocessing them is a solution for their cycle end. A list of reprocessing scenarios has been set the most realistic being a nitric dissolution close to the classic spent fuel reprocessing. This uranium silicide fuel contains a lot of silicon and few things are known about polymerization of silicic acid in concentrated nitric acid. The study of this polymerization allows to point out the main parameters: acidity, temperature, silicon concentration. The presence of aluminum seems to speed up heavily the polymerization. It has been impossible to find an analytical technique smart and fast enough to characterize the first steps of silicic acid polymerization. However the action of silicic species on emulsions stabilization formed by mixing them with an organic phase containing TBP has been studied, Silicon slows down the phase separation by means of oligomeric species forming complex with TBP. The existence of these intermediate species is short and heating can avoid any stabilization. When non irradiated uranium silicide fuel is attacked by a nitric solution, aluminum and uranium are quickly dissolved whereas silicon mainly stands in solid state. That builds a gangue of hydrated silica around the uranium silicide particulates without preventing uranium dissolution. A small part of silicon passes into the solution and polymerize towards the highly poly-condensed forms, just 2% of initial silicon is still in molecular form at the end of the dissolution. A thermal treatment of the fuel element, by forming inter-metallic phases U-Al-Si, allows the whole silicon to pass into the solution and next to precipitate. The behavior of silicon in spent fuels should be between these two situations. (author)

  6. Deep desulfurization of diesel fuels by catalytic oxidation

    Institute of Scientific and Technical Information of China (English)

    YU Guoxian; CHEN Hui; LU Shanxiang; ZHU Zhongnan

    2007-01-01

    Reaction feed was prepared by dissolving dibenzothiophene (DBT),which was selected as a model organosulfur compound in diesel fuels,in n-octane.The oxidant was a 30 wt-% aqueous solution of hydrogen peroxide.Catalytic performance of the activated carbons with saturation adsorption of DBT was investigated in the presence of formic acid.In addition,the effects of activated carbon dosage,formic acid concentration,initial concentration of hydrogen peroxide,initial concentration of DBT and reaction temperature on the oxidation of DBT were investigated.Experimental results indicated that performic acid and the hydroxyl radicals produced are coupled to oxidize DBT with a conversion ratio of 100%.Catalytic performance of the combination of activated carbon and formic acid is higher than that ofouly formic acid.The concentration of formic acid,activated carbon dosage,initial concentration of hydrogen peroxide and reaction temperature affect the oxidative removal of DBT.The higher the initial concentration of DBT in the n-octane solution,the more difficult the deep desulfurization by oxidation is.

  7. Chemical deactivation of V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} SCR catalysts by additives and impurities from fuels, lubrication oils, and urea solution. Part 1. Catalytic studies

    Energy Technology Data Exchange (ETDEWEB)

    Kroecher, Oliver; Elsener, Martin [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2008-01-10

    The influence of the combustion products of different lubrication oil additives (Ca, Mg, Zn, P, B, Mo) and impurities in Diesel fuel (K from raps methyl ester) or urea solution (Ca, K) on the activity and selectivity of vanadia-based SCR catalysts were investigated. Standard V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} catalysts coated on metal substrates (400 cpsi) were impregnated with water soluble compounds of these elements and calcined at 400 and 550 C, in order to investigate the chemical deactivation potential of different elements and combinations of them. It was found that potassium strongly reduced the adsorption equilibrium constant K{sub NH{sub 3}} of ammonia. At small ammonia concentrations in the feed, only part of the active sites were covered with ammonia resulting in a reduced SCR reaction rate. At high ammonia concentrations, the surface coverage and SCR reaction rate increased, but high SCR activity at concurrent low ammonia emissions was impossible. Calcium caused less deactivation than potassium and did not affect the ammonia adsorption to the same extent, but it lowered the intrinsic SCR reaction rate. Moreover, deactivation by calcium was much reduced if counter-ions of inorganic acids were present (order of improvement: SO{sub 4}{sup 2-} > PO{sub 4}{sup 3-} > BO{sub 3}{sup 3-}). Zinc was again less deactivating than calcium, but the positive effect of the counter-ions was weaker than in case of calcium. The degree of N{sub 2}O production at T > 500 C, which is typical for V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} catalysts, was not influenced by the different compounds, except for molybdenum, which induced a small increase in N{sub 2}O formation. (author)

  8. Bioprospecting--fuels from fungi.

    Science.gov (United States)

    Strobel, Gary Allan

    2015-05-01

    The world has a continuing demand and utility for liquid fuels to power its societies. The utilization of crude oil based fuels is leading to a dramatic increase in the CO2 content of the atmosphere which is being related to a dangerously warming earth. Having liquid fuels that are derived from biological sources is one solution to this growing problem since the carbon being utilized is only from recycled sources. Presently, the microbes, having the greatest impact on the world's economies, producing liquid fuel are various yeasts producing ethanol. Other microbial sources need to be sought since ethanol is not the most desirable fuel and yeasts require simple sugars to carry out the fermentation processes. Recently, several endophytic fungi have been described that make hydrocarbons with fuel potential (Mycodiesel). Among others the compounds found in the volatile phases of these cultures include alkanes, branched alkanes, cyclohexanes, cyclopentanes, and alkyl alcohols/ketones, benzenes and polyaromatic hydrocarbons. Most importantly, generally these organisms make hydrocarbons while utilizing complex carbohydrates found in all plant-based agricultural wastes. Also discussed in this review is a rationale for finding hydrocarbon producing endophytes as well as examples of other promising hydrocarbon producers-Nodulisporium spp. which make 1,8-cineole and families of other hydrocarbons. Extremely favorable results of engine and fuel testing experiments recently completed on cineole and other products of Nodulisporium sp. are also presented. Finally, there is a brief discussion on the main limiting steps in the domestication of these fungi.

  9. Peer reviewed: Characterizing aquatic dissolved organic matter

    Science.gov (United States)

    Leenheer, Jerry A.; Croué, Jean-Philippe

    2003-01-01

    Whether it causes aesthetic concerns such as color, taste, and odor; leads to the binding and transport of organic and inorganic contaminants; produces undesirable disinfection byproducts; provides sources and sinks for carbon; or mediates photochemical processes, the nature and properties of dissolved organic matter (DOM) in water are topics of significant environmental interest. DOM is also a major reactant in and product of biogeochemical processes in which the material serves as a carbon and energy source for biota and controls levels of dissolved oxygen, nitrogen, phosphorus, sulfur, numerous trace metals, and acidity.

  10. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  11. Transport fuel

    DEFF Research Database (Denmark)

    Ronsse, Frederik; Jørgensen, Henning; Schüßler, Ingmar

    2014-01-01

    Worldwide, the use of transport fuel derived from biomass increased four-fold between 2003 and 2012. Mainly based on food resources, these conventional biofuels did not achieve the expected emission savings and contributed to higher prices for food commod - ities, especially maize and oilseeds...

  12. Development of Zingiber officinale in oral dissolving films: Effect of polymers on in vitro, in vivo parameters and clinical efficacy

    OpenAIRE

    2011-01-01

    Oral dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules, etc. Zingiber officinale, has been used for medicinal purpose since antiquity to treat motion sickness, pregnancy, and cancer-chemotherapy-induced vomiting, mild stomach upset, cough, chronic bronchial problems, and low-grade infections of all kinds and anorexia condition. This work investigates the possibility of developing Zingiber officinale oral dissolving films allo...

  13. Intelligent Fault Diagnosis in Power Transformer with Using Dissolved Gas Analysis in different Standards by Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Rahmat Houshmand

    2007-09-01

    Full Text Available The power electric transformer fault diagnosis is based on dissolved gas-in-oil analysis (DGA. the conventional fault diagnosis methods, i.e. the ratio methods (Rogers, Dornenburg and IEC and the key gas method, have limitations such as the “no decision” problem. Various artificial intelligence techniques may help solve the problems and present a better solution. In this paper present a fuzzy systems to fault diagnosis in power electric transformer by dissolved we gas analysis.

  14. DISSOLUTION OF IRRADIATED MURR FUEL ASSEMBLIES

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.

    2010-06-17

    A literature survey on the dissolution of spent nuclear fuel from the University of Missouri Research Reactor (MURR) has been performed. This survey encompassed both internal and external literature sources for the dissolution of aluminum-clad uranium alloy fuels. The most limiting aspect of dissolution in the current facility configuration involves issues related to the control of the flammability of the off-gas from this process. The primary conclusion of this work is that based on past dissolution of this fuel in H-Canyon, four bundles of this fuel (initial charge) may be safely dissolved in a nitric acid flowsheet catalyzed with 0.002 M mercuric nitrate using a 40 scfm purge to control off-gas flammability. The initial charge may be followed by a second charge of up to five bundles to the same dissolver batch depending on volume and concentration constraints. The safety of this flowsheet relies on composite lower flammability limits (LFL) estimated from prior literature, pilot-scale work on the dissolution of site fuels, and the proposed processing flowsheet. Equipment modifications or improved LFL data offer the potential for improved processing rates. The fuel charging sequence, as well as the acid and catalyst concentrations, will control the dissolution rate during the initial portion of the cycle. These parameters directly impact the hydrogen and off-gas generation and, along with the purge flowrate determine the number of bundles that may be charged. The calculation approach within provides Engineering a means to determine optimal charging patterns. Downstream processing of this material should be similar to that of recent processing of site fuels requiring only minor adjustments of the existing flowsheet parameters.

  15. LIFE Materails: Molten-Salt Fuels Volume 8

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R; Brown, N; Caro, A; Farmer, J; Halsey, W; Kaufman, L; Kramer, K; Latkowski, J; Powers, J; Shaw, H; Turchi, P

    2008-12-11

    The goals of the Laser Inertial Fusion Fission Energy (LIFE) is to use fusion neutrons to fission materials with no enrichment and minimum processing and have greatly reduced wastes that are not of interest to making weapons. Fusion yields expected to be achieved in NIF a few times per day are called for with a high reliable shot rate of about 15 per second. We have found that the version of LIFE using TRISO fuel discussed in other volumes of this series can be modified by replacing the molten-flibe-cooled TRISO fuel zone with a molten salt in which the same actinides present in the TRISO particles are dissolved in the molten salt. Molten salts have the advantage that they are not subject to radiation damage, and hence overcome the radiation damage effects that may limit the lifetime of solid fuels such as TRISO-containing pebbles. This molten salt is pumped through the LIFE blanket, out to a heat exchanger and back into the blanket. To mitigate corrosion, steel structures in contact with the molten salt would be plated with tungsten or nickel. The salt will be processed during operation to remove certain fission products (volatile and noble and semi-noble fission products), impurities and corrosion products. In this way neutron absorbers (fission products) are removed and neutronics performance of the molten salt is somewhat better than that of the TRISO fuel case owing to the reduced parasitic absorption. In addition, the production of Pu and rare-earth elements (REE) causes these elements to build up in the salt, and leads to a requirement for a process to remove the REE during operation to insure that the solubility of a mixed (Pu,REE)F3 solid solution is not exceeded anywhere in the molten salt system. Removal of the REE will further enhance the neutronics performance. With molten salt fuels, the plant would need to be safeguarded because materials of interest for weapons are produced and could potentially be removed.

  16. FLUORESCENCE IN DISSOLVED FRACTIONS OF HUMAN ENAMEL

    NARCIS (Netherlands)

    HAFSTROMBJORKMAN, U; SUNDSTROM, F; TENBOSCH, JJ

    Fluorescence induced by laser light is useful in early detection of enamel caries. The present work studied the fluorescence emission pattern in dissolved human enamel and in different molecular weight fractions obtained after gel chromatography or dialysis followed by ultrafiltration. For

  17. Modeling Fish Growth in Low Dissolved Oxygen

    Science.gov (United States)

    Neilan, Rachael Miller

    2013-01-01

    This article describes a computational project designed for undergraduate students as an introduction to mathematical modeling. Students use an ordinary differential equation to describe fish weight and assume the instantaneous growth rate depends on the concentration of dissolved oxygen. Published laboratory experiments suggest that continuous…

  18. Why do Worker-Firm Matches Dissolve?

    NARCIS (Netherlands)

    Gielen, A. C.; van Ours, J.C.

    2006-01-01

    In a dynamic labor market worker-firm matches dissolve frequently causing workers to separate and firms to look for replacements.A separation may be initiated by the worker (a quit) or the firm (a layoff), or may result from a joint decision.A dissolution of a worker-firm match may be ineffcient if

  19. Dissolved aluminium in the Southern Ocean

    NARCIS (Netherlands)

    Middag, R.; van Slooten, C.; de Baar, H. J. W.; Laan, P.

    2011-01-01

    Dissolved aluminium (Al) occurs in a wide range of concentrations in the world oceans. The concentrations of Al in the Southern Ocean are among the lowest ever observed. An all-titanium CTD sampling system makes it possible to study complete deep ocean sections of Al and other trace elements with th

  20. Dissolved petroleum hydrocarbons in the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Topgi, R.S.; Noronha, R.J.; Fondekar, S.P.

    Mean dissolved petroleum hydrocarbons, measured using UV-spectrophotometry, at 0 and 10m were 51 plus or minus 1 and 55 plus or minus 1.2 mu g/litre respectively; range of variation being between 28 and 83 mu g/litre. Very little difference...

  1. Total dissolved carbohydrate in Mahi river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Rokade, M.A.; Zingde, M.D.

    Total dissolved carbohydrate varied from 4.37-15 mg l-1 and 3.71-15.95 mg l-1 in the surface and bottom samples respectively. Highest concentration of carbohydrate was observed at station 1 which decreased downward upto Station 6 which showed...

  2. Proton exchange membrane fuel cells modeling

    CERN Document Server

    Gao, Fengge; Miraoui, Abdellatif

    2013-01-01

    The fuel cell is a potential candidate for energy storage and conversion in our future energy mix. It is able to directly convert the chemical energy stored in fuel (e.g. hydrogen) into electricity, without undergoing different intermediary conversion steps. In the field of mobile and stationary applications, it is considered to be one of the future energy solutions.Among the different fuel cell types, the proton exchange membrane (PEM) fuel cell has shown great potential in mobile applications, due to its low operating temperature, solid-state electrolyte and compactness.This book pre

  3. Estimation of CO concentration in high temperature PEM fuel cells using electrochemical impedance

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2013-01-01

    , a possible solution, an avoidance of the long recharging time is combining them with the use of fuel cells. Fuel cells continuously deliver electrical power as long as a proper fuel supply is maintained. The ideal fuel for fuel cells is hydrogen, which in it’s pure for has high volumetric storage...... requirements. One of the solutions to this fuel storage problem is using liquid fuels such as methanol that through a chemical reformer converts the fuel into a hydrogen rich gas mixture. Methanol is a liquid fuel, which has low storage requirements and high temperature polymer electrolyte membrane (HTPEM......) fuel cells can eciently run on the reformed hydrogen rich gas, although with reduced performance depending on the contaminants, such as CO, in the gas. By estimating the amount of CO in the fuel cell, it could be possible to adjust the fuel cell system operating parameters to increase performance...

  4. Photochemical and Nonphotochemical Transformations of Cysteine with Dissolved Organic Matter.

    Science.gov (United States)

    Chu, Chiheng; Erickson, Paul R; Lundeen, Rachel A; Stamatelatos, Dimitrios; Alaimo, Peter J; Latch, Douglas E; McNeill, Kristopher

    2016-06-21

    Cysteine (Cys) plays numerous key roles in the biogeochemistry of natural waters. Despite its importance, a full assessment of Cys abiotic transformation kinetics, products and pathways under environmental conditions has not been conducted. This study is a mechanistic evaluation of the photochemical and nonphotochemical (dark) transformations of Cys in solutions containing chromophoric dissolved organic matter (CDOM). The results show that Cys underwent abiotic transformations under both dark and irradiated conditions. Under dark conditions, the transformation rates of Cys were moderate and were highly pH- and temperature-dependent. Under UVA or natural sunlight irradiations, Cys transformation rates were enhanced by up to two orders of magnitude compared to rates under dark conditions. Product analysis indicated cystine and cysteine sulfinic acid were the major photooxidation products. In addition, this study provides an assessment of the contributions of singlet oxygen, hydroxyl radical, hydrogen peroxide, and triplet dissolved organic matter to the CDOM-sensitized photochemical oxidation of Cys. The results suggest that another unknown pathway was dominant in the CDOM-sensitized photodegradation of Cys, which will require further study to identify.

  5. Enhanced dissolution of cinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades

    Science.gov (United States)

    Ravichandran, Mahalingam; Aiken, George R.; Reddy, Michael M.; Ryan, Joseph N.

    1998-01-01

    Organic matter isolated from the Florida Everglades caused a dramatic increase in mercury release (up to 35 μM total dissolved mercury) from cinnabar (HgS), a solid with limited solubility. Hydrophobic (a mixture of both humic and fulvic) acids dissolved more mercury than hydrophilic acids and other nonacid fractions of dissolved organic matter (DOM). Cinnabar dissolution by isolated organic matter and natural water samples was inhibited by cations such as Ca2+. Dissolution was independent of oxygen content in experimental solutions. Dissolution experiments conducted in DI water (pH = 6.0) had no detectable (pH 6.0. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter.

  6. Reaction of erythromycin with dissolved oxygen on gold nanoparticle-modified glassy carbon electrodes

    Institute of Scientific and Technical Information of China (English)

    LI Xue; FU Ying; WANG Jian-xiu; L(U) Hui-dan; XU Mao-tian

    2008-01-01

    Cyclic voltammetry was used to investigate the reaction of erythromycin (EM) with dissolved oxygen on gold nanoparticle-modified electrodes prepared via electrodeposition. A well-defined reduction peak at -0.420 V and a reoxidation peak at -0.055V were observed. With the addition of EM into the NaOH solution containing dissolved oxygen, the oxidation peak at -0.055 V was still indiscernible. However, a new oxidation peak at 0.200V appeared, which suggests the interaction between EM and dissolved oxygen. Therefore, this method can be used for the analysis of EM in tablets. The present method is simple, reproducible,and does not require complex analytical instruments.

  7. A review of fuel cell systems for maritime applications

    Science.gov (United States)

    van Biert, L.; Godjevac, M.; Visser, K.; Aravind, P. V.

    2016-09-01

    Progressing limits on pollutant emissions oblige ship owners to reduce the environmental impact of their operations. Fuel cells may provide a suitable solution, since they are fuel efficient while they emit few hazardous compounds. Various choices can be made with regard to the type of fuel cell system and logistic fuel, and it is unclear which have the best prospects for maritime application. An overview of fuel cell types and fuel processing equipment is presented, and maritime fuel cell application is reviewed with regard to efficiency, gravimetric and volumetric density, dynamic behaviour, environmental impact, safety and economics. It is shown that low temperature fuel cells using liquefied hydrogen provide a compact solution for ships with a refuelling interval up to a tens of hours, but may result in total system sizes up to five times larger than high temperature fuel cells and more energy dense fuels for vessels with longer mission requirements. The expanding infrastructure of liquefied natural gas and development state of natural gas-fuelled fuel cell systems can facilitate the introduction of gaseous fuels and fuel cells on ships. Fuel cell combined cycles, hybridisation with auxiliary electricity storage systems and redundancy improvements are identified as topics for further study.

  8. Fuel control system for dual fuel engines

    Energy Technology Data Exchange (ETDEWEB)

    Helmich, M.J.; Ryan, W.P.; Marvin, D.H.

    1987-11-24

    A fuel governing system for an engine adapted for operation on a first fuel and a second fuel is described comprising: a first fuel governing system including a spontaneous motion metering means; and a second fuel governing system, the second fuel governing system further comprising: means for providing a first signal indicative of position of the first fuel metering means, which signal approximates total load on the engine, means for providing a second signal of the selected percentage of first fuel relative to total load, means for controlling flow of the second fuel to the engine, which flow causes reflective displacement of the first fuel metering means, means for determining the difference between the first signal and the second signal, which difference is indicative of distance the first fuel metering means must be moved to attain the selected percentage of first fuel relative to total load, and means for causing operation of the means for controlling flow of the second fuel to the engine to cause displacement of the first fuel metering means equal to the distance the first fuel metering means must be moved to attain the selected percentage of first fuel relative to total load.

  9. A Possible Solution for the U.S. Navy’s Addiction to Petroleum: A Business Case Analysis for Transitioning the U.S. Navy From Petroleum to Synthetic Fuel Resources

    Science.gov (United States)

    2007-03-01

    temperatures , to be useful. Today’s tactical vehicles have a limited fuel volume and fuel weight capacity. Furthermore, tactical vehicles are subject to...Kuwait or Dubai and crashing it into Abqaiq or Ras Tanura, could turn the complex into an inferno. 16 This could take up to 50 percent of Saudi...are inconsistencies within the data that affect the capital and operating expenses of each cost study. For example if the feedstock is coal, there

  10. Modification of Karl Fischer Method for Determination of Water in light Petroleum Products Including Aviation Fuels

    Directory of Open Access Journals (Sweden)

    R. C. Misra

    1971-04-01

    Full Text Available Classical Karl Fischer method has been modified so as to make it suitable for determining free and dissolved water present in aviation fuels in excess of 10 ppm which is considered as limiting concentration value for safe fueling of aircrafts particularly in the arduous climatic conditions as encountered in military operations. The modified method employed a special ethylene glyccl solvent mixture and another water saturated fuel sample as blank.

  11. Small-scale bio fuelled heat and power - requirements for standardized technical and fuel solutions from a systems perspective; Smaaskalig biobraenslebaserad kraftvaerme - foerutsaettningar foer standardiserade loesningar med avseende paa teknik och braenslen i ett systemperspektiv

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, Olle; Johansson, Kent; Steinwall, Pontus [Sycon Energikonsult AB, Malmoe (Sweden)

    2001-01-01

    Different techniques for small-scale heat and power generation have been investigated. The included cycles are steam turbine, diesel engine, Otto engine, Stirling engine, gas turbine and organic Rankine cycle (ORC). For steam turbines, Stirling engine, and indirectly fired gas turbines, the combustion can be placed in a relatively conventional furnace, which gives a fairly free choice of fuel. In other cycles like the traditional gas turbine cycle, diesel engine and Otto engine, the fuel should be in the gas or liquid phase. Experiments are in progress to use wood pf (pulverised fuel) as fuel. The technique for plants based on steam turbine, diesel engine, Otto engine, conventional gas turbine and ORC based on different forms of bio fuel exist already today. For Stirling engine, gas turbine with HAT cycle (Humid Air Turbine) and indirectly fired gas turbine further development is needed before the technique will be commercially available using bio fuel. An interesting process coupling is a gas engine combined with a gasifier. This coupling can be a competitive choice to the other processes if the problems with gas cleaning can be solved.

  12. Electrodialysis-ion exchange for the separation of dissolved salts

    Energy Technology Data Exchange (ETDEWEB)

    Baroch, C.J. [Wastren, Inc., Westminster, CO (United States); Grant, P.J. [Wastren, Inc., Hummelstown, PA (United States)

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

  13. Proof of concept experiments of the multi-isotope process monitor: An online, nondestructive, near real-time monitor for spent nuclear fuel reprocessing facilities

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Christopher R., E-mail: christopher.orton@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99354 (United States); Fraga, Carlos G., E-mail: carlos.fraga@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99354 (United States); Christensen, Richard N., E-mail: christensen.3@osu.edu [The Ohio State University, 201W. 19th Avenue, Columbus, Ohio 43210 (United States); Schwantes, Jon M., E-mail: jon.schwantes@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99354 (United States)

    2012-04-21

    Operators, national regulatory agencies and the IAEA will require the development of advanced technologies to efficiently control and safeguard nuclear material at increasingly large-scale nuclear recycling facilities. Ideally, the envisioned technologies would be capable of non-destructive, near real-time (NRT), autonomous process monitoring. This paper describes results from proof-of-principle experiments designed to test the multi-isotope process (MIP) monitor, a novel approach to monitoring and safeguarding reprocessing facilities. The MIP Monitor combines the detection of intrinsic gamma ray signatures emitted from process solutions with multivariate analysis to detect off-normal conditions in process streams nondestructively and in NRT. Commercial spent nuclear fuel of various irradiation histories was dissolved and separated using a PUREX-based batch solvent extraction. Extractions were performed at various nitric acid concentrations to mimic both normal and off-normal industrial plant operating conditions. Principal component analysis (PCA) was applied to the simulated gamma spectra to investigate pattern variations as a function of acid concentration, burnup and cooling time. Partial least squares (PLS) regression was applied to attempt to quantify both the acid concentration and burnup of the dissolved spent fuel during the initial separation stage of recycle. The MIP Monitor demonstrated sensitivity to induced variations of acid concentration, including the distinction of {+-}1.3 M variation from normal process conditions by way of PCA. Acid concentration was predicted using measurements from the organic extract and PLS resulting in predictions with <0.7 M relative error. Quantification of burnup levels from dissolved fuel spectra using PLS was demonstrated to be within 2.5% of previously measured values.

  14. Proof of Concept Experiments of the Multi-Isotope Process Monitor: An Online, Nondestructive, Near Real-Time Monitor for Spent Nuclear Fuel Reprocessing Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Christopher R.; Fraga, Carlos G.; Christensen, Richard; Schwantes, Jon M.

    2012-04-21

    Operators, national regulatory agencies and the IAEA will require the development of advanced technologies to efficiently control and safeguard nuclear material at increasingly large-scale nuclear recycling facilities. Ideally, the envisioned technologies would be capable of non-destructive, near-real-time (NRT), autonomous process monitoring. This paper describes results from proof-of-principle experiments designed to test the Multi-Isotope Process (MIP) Monitor, a novel approach to safeguarding reprocessing facilities. The MIP Monitor combines the detection of intrinsic gamma ray signatures emitted from process solutions with multivariate analysis to detect off-normal conditions in process streams nondestructively and in NRT. Commercial spent nuclear fuel of various irradiation histories was dissolved and separated using a PUREX-based batch solvent extraction. Extractions were performed at various nitric acid concentrations to mimic both normal and off-normal industrial plant operating conditions. Principal Component Analysis (PCA) was applied to the simulated gamma spectra to investigate pattern variations as a function of acid concentration, burnup and cooling time. Partial Least Squares (PLS) regression was applied to attempt to quantify both the acid concentration and burnup of the dissolved spent fuel during the initial separation stage of recycle. The MIP Monitor demonstrated sensitivity to induced variations of acid concentration, including the distinction of {+-} 1.3 M variation from normal process conditions by way of PCA. Acid concentration was predicted using measurements from the organic extract and PLS resulting in predictions with <0.7 M relative error. Quantification of burnup levels from dissolved fuel spectra using PLS was demonstrated to be within 2.5% of previously measured values.

  15. Proof of concept experiments of the multi-isotope process monitor: An online, nondestructive, near real-time monitor for spent nuclear fuel reprocessing facilities

    Science.gov (United States)

    Orton, Christopher R.; Fraga, Carlos G.; Christensen, Richard N.; Schwantes, Jon M.

    2012-04-01

    Operators, national regulatory agencies and the IAEA will require the development of advanced technologies to efficiently control and safeguard nuclear material at increasingly large-scale nuclear recycling facilities. Ideally, the envisioned technologies would be capable of non-destructive, near real-time (NRT), autonomous process monitoring. This paper describes results from proof-of-principle experiments designed to test the multi-isotope process (MIP) monitor, a novel approach to monitoring and safeguarding reprocessing facilities. The MIP Monitor combines the detection of intrinsic gamma ray signatures emitted from process solutions with multivariate analysis to detect off-normal conditions in process streams nondestructively and in NRT. Commercial spent nuclear fuel of various irradiation histories was dissolved and separated using a PUREX-based batch solvent extraction. Extractions were performed at various nitric acid concentrations to mimic both normal and off-normal industrial plant operating conditions. Principal component analysis (PCA) was applied to the simulated gamma spectra to investigate pattern variations as a function of acid concentration, burnup and cooling time. Partial least squares (PLS) regression was applied to attempt to quantify both the acid concentration and burnup of the dissolved spent fuel during the initial separation stage of recycle. The MIP Monitor demonstrated sensitivity to induced variations of acid concentration, including the distinction of ±1.3 M variation from normal process conditions by way of PCA. Acid concentration was predicted using measurements from the organic extract and PLS resulting in predictions with <0.7 M relative error. Quantification of burnup levels from dissolved fuel spectra using PLS was demonstrated to be within 2.5% of previously measured values.

  16. Benthic flux of dissolved nickel into the water column of south San Francisco Bay

    Science.gov (United States)

    Topping, B.R.; Kuwabara, J.S.; Parcheso, Francis; Hager, S.W.; Arnsberg, A.J.; Murphy, Fred

    2001-01-01

    Field and laboratory studies were conducted between April, 1998 and May, 1999 to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) nickel between the bottom sediment and water column at three sites in the southern component of San Francisco Bay (South Bay), California. Dissolved nickel and predominant ligands (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest, although a variety of ancillary measurements were also performed to provide a framework for interpretation. Results described herein integrate information needs identified by the State Water Resources Control Board and local stakeholders with fundamental research associated with the U.S. Geological Survey Toxic Substances Hydrology Program. Dissolved-Ni concentrations in the bottom water over the three sampling dates ranged from 34 to 43 nanomoles per liter. Dissolved-macronutrient concentrations in the bottom water were consistently higher (frequently by orders of magnitude) than surface-water determinations reported for similar times and locations (Regional Monitoring Program, 2001). This is consistent with measured positive benthic fluxes for the macronutrients. Benthic-flux estimates for dissolved nickel from core-incubations, when areally averaged over the South Bay, were significant (that is, of equivalent or greater order of magnitude) relative to previously reported freshwater point and non-point sources. This observation is consistent with previous determinations for other metals, and with the potential remobilization of sediment-associated metals that have been ubiquitously distributed in the South Bay. Similar to dissolved-nickel results, benthic flux of macronutrients was also consistently significant relative to surface-water inputs. These results add to a growing body of knowledge that strongly suggests a need to consider contaminant transport across the sediment-water interface when establishing future

  17. Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean

    Science.gov (United States)

    Resing, Joseph A.; Sedwick, Peter N.; German, Christopher R.; Jenkins, William J.; Moffett, James W.; Sohst, Bettina M.; Tagliabue, Alessandro

    2015-07-01

    Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.

  18. Mathematical Model of the Jet Engine Fuel System

    Science.gov (United States)

    Klimko, Marek

    2015-05-01

    The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor) engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator) will be described, with respect to advanced predetermined simplifications.

  19. Mathematical Model of the Jet Engine Fuel System

    Directory of Open Access Journals (Sweden)

    Klimko Marek

    2015-01-01

    Full Text Available The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator will be described, with respect to advanced predetermined simplifications.

  20. Electrolysis cell for reprocessing plutonium reactor fuel

    Science.gov (United States)

    Miller, William E.; Steindler, Martin J.; Burris, Leslie

    1986-01-01

    An electrolytic cell for refining a mixture of metals including spent fuel containing U and Pu contaminated with other metals, the cell including a metallic pot containing a metallic pool as one anode at a lower level, a fused salt as the electrolyte at an intermediate level and a cathode and an anode basket in spaced-apart positions in the electrolyte with the cathode and anode being retractable to positions above the electrolyte during which spent fuel may be added to the anode basket and the anode basket being extendable into the lower pool to dissolve at least some metallic contaminants, the anode basket containing the spent fuel acting as a second anode when in the electrolyte.

  1. Quadratic reactivity fuel cycle model

    Energy Technology Data Exchange (ETDEWEB)

    Lewins, J.D.

    1985-11-01

    For educational purposes it is highly desirable to provide simple yet realistic models for fuel cycle and fuel economy. In particular, a lumped model without recourse to detailed spatial calculations would be very helpful in providing the student with a proper understanding of the purposes of fuel cycle calculations. A teaching model for fuel cycle studies based on a lumped model assuming the summability of partial reactivities with a linear dependence of reactivity usefully illustrates fuel utilization concepts. The linear burnup model does not satisfactorily represent natural enrichment reactors. A better model, showing the trend of initial plutonium production before subsequent fuel burnup and fission product generation, is a quadratic fit. The study of M-batch cycles, reloading 1/Mth of the core at end of cycle, is now complicated by nonlinear equations. A complete account of the asymptotic cycle for any order of M-batch refueling can be given and compared with the linear model. A complete account of the transient cycle can be obtained readily in the two-batch model and this exact solution would be useful in verifying numerical marching models. It is convenient to treat the parabolic fit rho = 1 - tau/sup 2/ as a special case of the general quadratic fit rho = 1 - C/sub tau/ - (1 - C)tau/sup 2/ in suitably normalized reactivity and cycle time units. The parabolic results are given in this paper.

  2. A highly accurate method for determination of dissolved oxygen: gravimetric Winkler method.

    Science.gov (United States)

    Helm, Irja; Jalukse, Lauri; Leito, Ivo

    2012-09-05

    A high-accuracy Winkler titration method has been developed for determination of dissolved oxygen concentration. Careful analysis of uncertainty sources relevant to the Winkler method was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. The most important improvements were: gravimetric measurement of all solutions, pre-titration to minimize the effect of iodine volatilization, accurate amperometric end point detection and careful accounting for dissolved oxygen in the reagents. As a result, the developed method is possibly the most accurate method of determination of dissolved oxygen available. Depending on measurement conditions and on the dissolved oxygen concentration the combined standard uncertainties of the method are in the range of 0.012-0.018 mg dm(-3) corresponding to the k=2 expanded uncertainty in the range of 0.023-0.035 mg dm(-3) (0.27-0.38%, relative). This development enables more accurate calibration of electrochemical and optical dissolved oxygen sensors for routine analysis than has been possible before.

  3. Coulometric determination of dissolved hydrogen with a multielectrolytic modified carbon felt electrode-based sensor

    Institute of Scientific and Technical Information of China (English)

    Hiroaki Matsuura; Yosuke Yamawaki; Kosuke Sasaki; Shunichi Uchiyama

    2013-01-01

    A multielectrolytic modified carbon electrode (MEMCE) was fabricated by the electrolytic-oxidation/reduction processes.First,the functional groups containing nitrogen atoms such as amino group were introduced by the electrode oxidation of carbon felt electrode in an ammonium carbamate aqueous solution,and next,this electrode was electroreduced in sulfuric acid.The redox waves between hydrogen ion and hydrogen molecule at highly positive potential range appeared in the cyclic voltammogram obtained by MEMCE.A coulometric cell using MEMCE with a catalytic activity of electrooxidation of hydrogen molecule was constructed and was used for the measurement of dissolved hydrogen.The typical current vs.time curve was obtained by the repetitive measurement of the dissolved hydrogen.These curves indicated that the measurement of dissolved hydrogen was finished completely in a very short time (ca.10sec).A linear relationship was obtained between the electrical charge needed for the electrooxidation process of hydrogen molecule and dissolved hydrogen concentration.This indicates that the developed coulometfic method can be used for the determination of the dissolved hydrogen concentration.

  4. Multi-Fuel oxidation in Solid Oxide Fuel Cells: Model anodes and system studies

    NARCIS (Netherlands)

    Patel, H.C.

    2015-01-01

    With the evolution of renewable energy technologies it has become necessary that a balance is found between power production with conventional energy sources and other long term solutions. SOFCs offer an alternative for utilising conventional fossil fuels as well as sustainable biomass derived fuels

  5. Use of Stable Noble Gases as a Predictor of Reactor Fuel Type and Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Fearey, B.L.; Charlton, W.S.; Perry, R.T.; Poths, J.; Wilson, W.B.; Hemberger, P.H.; Nakhleh, C.W.; Stanbro, W.D.

    1999-08-30

    Ensuring spent reactor fuel is not produced to provide weapons-grade plutonium is becoming a major concern as many countries resort to nuclear power as a solution to their energy problems. Proposed solutions range from the development of proliferation resistant fuel to continuous monitoring of the fuel. This paper discusses the use of the stable isotopes of the fissiogenic noble gases, xenon and krypton, for determining the burnup characteristics, fuel type, and the reactor type of the fuel from which the sample was obtained. The gases would be collected on-stack as the fuel is reprocessed, and thus confirm that the fuel is as declared.

  6. Preservation of samples for dissolved mercury

    Science.gov (United States)

    Hamlin, S.N.

    1989-01-01

    Water samples for dissolved mercury requires special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid-oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean-up procedures.Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a

  7. Dissolvable microneedle fabrication using piezoelectric dispensing technology.

    Science.gov (United States)

    Allen, Evin A; O'Mahony, Conor; Cronin, Michael; O'Mahony, Thomas; Moore, Anne C; Crean, Abina M

    2016-03-16

    Dissolvable microneedle (DMN) patches are novel dosage forms for the percutaneous delivery of vaccines. DMN are routinely fabricated by dispensing liquid formulations into microneedle-shaped moulds. The liquid formulation within the mould is then dried to create dissolvable vaccine-loaded microneedles. The precision of the dispensing process is critical to the control of formulation volume loaded into each dissolvable microneedle structure. The dispensing process employed must maintain vaccine integrity. Wetting of mould surfaces by the dispensed formulation is also an important consideration for the fabrication of sharp-tipped DMN. Sharp-tipped DMN are essential for ease of percutaneous administration. In this paper, we demonstrate the ability of a piezoelectric dispensing system to dispense picolitre formulation volumes into PDMS moulds enabling the fabrication of bilayer DMN. The influence of formulation components (trehalose and polyvinyl alcohol (PVA) content) and piezoelectric actuation parameters (voltage, frequency and back pressure) on drop formation is described. The biological integrity of a seasonal influenza vaccine following dispensing was investigated and maintained voltage settings of 30 V but undermined at higher settings, 50 and 80 V. The results demonstrate the capability of piezoelectric dispensing technology to precisely fabricate bilayer DMN. They also highlight the importance of identifying formulation and actuation parameters to ensure controlled droplet formulation and vaccine stabilisation.

  8. Aviation fuels outlook

    Science.gov (United States)

    Momenthy, A. M.

    1980-01-01

    Options for satisfying the future demand for commercial jet fuels are analyzed. It is concluded that the most effective means to this end are to attract more refiners to the jet fuel market and encourage development of processes to convert oil shale and coal to transportation fuels. Furthermore, changing the U.S. refineries fuel specification would not significantly alter jet fuel availability.

  9. Biosorption of copper (II) from aqueous solution by mycelial pellets ...

    African Journals Online (AJOL)

    Syvia

    2012-01-19

    Jan 19, 2012 ... A stock solution of copper (II) was prepared by dissolving required amount of ... Reagent Co., Ltd, Shanghai, China) in double distilled water to obtain a .... through sharing or exchange of electrons between adsorbent and ...

  10. PLUTONIUM METALLIC FUELS FOR FAST REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    STAN, MARIUS [Los Alamos National Laboratory; HECKER, SIEGFRIED S. [Los Alamos National Laboratory

    2007-02-07

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  11. The cost of spent fuel storage

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Palacios H, J. C.; Badillo, V.; Alonso, G., E-mail: ramon.ramirez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    Spent fuel is one of the most important issues in the nuclear industry, currently spent fuel management is been cause of great amount of research, investments, constructing repositories or constructing the necessary facilities to reprocess the fuel, and later to recycle the plutonium recovered in thermal reactors. What is the best solution?, or What is the best technology for an specific solution? Many countries have deferred the decision on selecting an option, while others works actively constructing repositories and others implementing the reprocessing facilities to recycle the plutonium obtained from nuclear spent fuel. In Mexico the nuclear power is limited to two reactors BWR type and medium size. So the nuclear spent fuel discharged has been accommodated at reactor's spent fuel pools. Originally these pools have enough capacity to accommodate spent fuel for the 40 years of designed plant operation. However currently, the plants are under a process for extended power up-rate to 20% of original power and also there are plans to extended operational life for 20 more years. Under these conditions there will not be enough room for spent fuel in the pools. (Author)

  12. RERTR Fuel Developmemt and Qualification Plan

    Energy Technology Data Exchange (ETDEWEB)

    Dan Wachs

    2007-01-01

    In late 2003 it became evident that U-Mo aluminum fuels under development exhibited significant fuel performance problems under the irradiation conditions required for conversion of most high-powered research reactors. Solutions to the fuel performance issue have been proposed and show promise in early testing. Based on these results, a Reduced Enrichment Research and Test Reactor (RERTR) program strategy has been mapped to allow generic fuel qualification to occur prior to the end of FY10 and reactor conversion to occur prior to the end of FY14. This strategy utilizes a diversity of technologies, test conditions, and test types. Scoping studies using miniature fuel plates will be completed in the time frame of 2006-2008. Irradiation of larger specimens will occur in the Advanced Test Reactor (ATR) in the United States, the Belgian Reactor-2 (BR2) reactor in Belgium, and in the OSIRIS reactor in France in 2006-2009. These scoping irradiation tests provide a large amount of data on the performance of advanced fuel types under irradiation and allow the down selection of technology for larger scale testing during the final stages of fuel qualification. In conjunction with irradiation testing, fabrication processes must be developed and made available to commercial fabricators. The commercial fabrication infrastructure must also be upgraded to ensure a reliable low enriched uranium (LEU) fuel supply. Final qualification of fuels will occur in two phases. Phase I will obtain generic approval for use of dispersion fuels with density less than 8.5 g-U/cm3. In order to obtain this approval, a larger scale demonstration of fuel performance and fabrication technology will be necessary. Several Materials Test Reactor (MTR) plate-type fuel assemblies will be irradiated in both the High Flux Reactor (HFR) and the ATR (other options include the BR2 and Russian Research Reactor, Dmitrovgrad, Russia [MIR] reactors) in 2008-2009. Following postirradiation examination, a report

  13. Recycle of electrolytically dissolved struvite as an alternative to enhance phosphate and nitrogen recovery from swine wastewater.

    Science.gov (United States)

    Liu, YingHao; Kumar, Sanjay; Kwag, JungHoon; Kim, JaeHwan; Kim, JeongDae; Ra, ChangSix

    2011-11-15

    Operational parameters such as electric voltage, NaCl, reaction time (RT) and initial struvite amount were optimized for struvite dissolution with a designed electrolysis reactor, and the effect of recycling the dissolved solution on the performance of struvite crystallization was also assessed. The electrolytic reactor was made of plexiglas having titanium plate coated with iridium oxide as anode (surface area: 400 cm(2)) and stainless steel plates as cathodes. For reutilization of dissolved struvite, four runs were conducted with different recycle ratio of the solution. Optimum conditions for the electric voltage, NaCl, RT and initial struvite amount were 7 V, 0.06%, 1.5h and 1.25 g/L, respectively. At the above optimized conditions, 49.17 mg/L phosphate (PO(4)(3-)-P) was dissolved and ammonium-nitrogen (NH(4)-N) got completely removed from the solution. When 0.0, 0.5, 1.0 and 2.0 moles of the dissolved struvite with respect to PO(4)(3-)-P in swine wastewater were recycled along with 0.5M magnesium chloride (MgCl(2)), the PO(4)(3-)-P removal was 63, 69, 71 and 79%, and NH(4)-N was 9, 31, 40 and 53%, respectively. Hence, the performance of struvite formation process was proportionally increased. It is concluded that struvite can be re-dissolved by electrolysis and reused as a source of P and Mg.

  14. Fuel processors for fuel cell APU applications

    Science.gov (United States)

    Aicher, T.; Lenz, B.; Gschnell, F.; Groos, U.; Federici, F.; Caprile, L.; Parodi, L.

    The conversion of liquid hydrocarbons to a hydrogen rich product gas is a central process step in fuel processors for auxiliary power units (APUs) for vehicles of all kinds. The selection of the reforming process depends on the fuel and the type of the fuel cell. For vehicle power trains, liquid hydrocarbons like gasoline, kerosene, and diesel are utilized and, therefore, they will also be the fuel for the respective APU systems. The fuel cells commonly envisioned for mobile APU applications are molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells (PEMFC). Since high-temperature fuel cells, e.g. MCFCs or SOFCs, can be supplied with a feed gas that contains carbon monoxide (CO) their fuel processor does not require reactors for CO reduction and removal. For PEMFCs on the other hand, CO concentrations in the feed gas must not exceed 50 ppm, better 20 ppm, which requires additional reactors downstream of the reforming reactor. This paper gives an overview of the current state of the fuel processor development for APU applications and APU system developments. Furthermore, it will present the latest developments at Fraunhofer ISE regarding fuel processors for high-temperature fuel cell APU systems on board of ships and aircrafts.

  15. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  16. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  17. Fuel cells: A survey

    Science.gov (United States)

    Crowe, B. J.

    1973-01-01

    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  18. Atomistic Simulations of Mass and Thermal Transport in Oxide Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders D. [Los Alamos National Laboratory; Uberuaga, Blas P. [Los Alamos National Laboratory; Du, Shiyu [Los Alamos National Laboratory; Liu, Xiang-Yang [Los Alamos National Laboratory; Nerikar, Pankaj [IBM; Stanek, Christopher R. [Los Alamos National Laboratory; Tonks, Michael [Idaho National Laboratory; Millet, Paul [Idaho National Laboratory; Biner, Bulent [Idaho National Laboratory

    2012-06-04

    In this talk we discuss simulations of the mass and thermal transport in oxide nuclear fuels. Redistribution of fission gases such as Xe is closely coupled to nuclear fuel performance. Most fission gases have low solubility in the fuel matrix, specifically the insolubility is most pronounced for large fission gas atoms such as Xe, and as a result there is a significant driving force for segregation of gas atoms to grain boundaries or dislocations and subsequently for nucleation of gas bubbles at these sinks. The first step of the fission gas redistribution is diffusion of individual gas atoms through the fuel matrix to existing sinks, which is governed by the activation energy for bulk diffusion. Fission gas bubbles are then formed by either separate nucleation events or by filling voids that were nucleated at a prior stage; in both cases their formation and latter growth is coupled to vacancy dynamics and thus linked to the production of vacancies via irradiation or thermal events. In order to better understand bulk Xe behavior (diffusion mechanisms) in UO{sub 2{+-}x} we first calculate the relevant activation energies using density functional theory (DFT) techniques. By analyzing a combination of Xe solution thermodynamics, migration barriers and the interaction of dissolved Xe atoms with U, we demonstrate that Xe diffusion predominantly occurs via a vacancy-mediated mechanism, though other alternatives may exist in high irradiation fields. Since Xe transport is closely related to diffusion of U vacancies, we have also studied the activation energy for this process. In order to explain the low value of 2.4 eV found for U migration from independent damage experiments (not thermal equilibrium) the presence of vacancy clusters must be included in the analysis. Next a continuum transport model for Xe and U is formulated based on the diffusion mechanisms established from DFT. After combining this model with descriptions of the interaction between Xe and grain

  19. Operando fuel cell spectroscopy

    Science.gov (United States)

    Kendrick, Ian Michael

    unobserved peaks corresponding to adsorbed ethanol. A modification to the operando fuel cell design allowed for acquisition of Raman spectra. A confocal Raman microscope enabled characterization of the MEA through depth profiling. The potential dependent peaks of an Fe-N x/C catalyst were identified and compared to the theoretical spectra of the proposed active sites. It was determined that oxygen adsorbed onto iron/iron oxide carbon nanostructures were responsible for the experimentally obtained peaks. This finding was supported by additional Raman studies carried out on a catalyst with these active sites removed through peroxide treatments. 1 Topsoe, H., Developments in operando studies and in situ characterization of heterogeneous catalysts. Journal of Catalysis, 2003. 216(1-2): p. 155-164. 2 Stamenkovic, V., et al., Vibrational properties of CO at the Pt(111)-solution interface: the anomalous stark-tuning slope. Journal of Physical Chemistry B, 2005. 109(2): p. 678-680. 3 Kendrick, I., et al., Elucidating the Ionomer-Electrified Metal Interface. J. Am. Chem. Soc., 2010. 132(49): p. 17611-17616. 4 Lamy, C. and Leger, J.M., FUEL-CELLS - APPLICATION TO ELECTRIC VEHICLES. Journal De Physique Iv, 1994. 4(C1): p. 253-281.

  20. Global Spent Fuel Logistics Systems Study (GSFLS). Volume 4. Pacific basin spent fuel logistics system

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    This report summarizes the conceptual framework for a Pacific Basin Spent Fuel Logistics System (PBSFLS); and preliminarily describes programatic steps that might be taken to implement such a system. The PBSFLS concept is described in terms of its technical and institutional components. The preferred PBSFLS concept embodies the rationale of emplacing a fuel cycle system which can adjust to the technical and institutional non-proliferation solutions as they are developed and accepted by nations. The concept is structured on the basis of initially implementing a regional spent fuel storage and transportation system which can technically and institutionally accommodate downstream needs for energy recovery and long-term waste management solutions.

  1. Future aviation fuels overview

    Science.gov (United States)

    Reck, G. M.

    1980-01-01

    The outlook for aviation fuels through the turn of the century is briefly discussed and the general objectives of the NASA Lewis Alternative Aviation Fuels Research Project are outlined. The NASA program involves the evaluation of potential characteristics of future jet aircraft fuels, the determination of the effects of those fuels on engine and fuel system components, and the development of a component technology to use those fuels.

  2. Dynamic leaching studies of 48 MWd/kgU UO2 commercial spent nuclear fuel under oxic conditions

    Science.gov (United States)

    Serrano-Purroy, D.; Casas, I.; González-Robles, E.; Glatz, J. P.; Wegen, D. H.; Clarens, F.; Giménez, J.; de Pablo, J.; Martínez-Esparza, A.

    2013-03-01

    The leaching of a high-burn-up spent nuclear fuel (48 MWd/KgU) has been studied in a carbonate-containing solution and under oxic conditions using a Continuously Stirred Tank Flow-Through Reactor (CSTR). Two samples of the fuel, one prepared from the centre of the pellet (labelled CORE) and another one from the fuel pellet periphery, enriched with the so-called High Burn-Up Structure (HBS, labelled OUT) have been used.For uranium and actinides, the results showed that U, Np, Am and Cm gave very similar normalized dissolution rates, while Pu showed slower dissolution rates for both samples. In addition, dissolution rates were consistently two to four times lower for OUT sample compared to CORE sample.Considering the fission products release the main results are that Y, Tc, La and Nd dissolved very similar to uranium; while Cs, Sr, Mo and Rb have up to 10 times higher dissolution rates. Rh, Ru and Zr seemed to have lower dissolution rates than uranium. The lowest dissolution rates were found for OUT sample.Three different contributions were detected on uranium release, modelled and attributed to oxidation layer, fines and matrix release.

  3. Dynamic leaching studies of 48 MWd/kgU UO{sub 2} commercial spent nuclear fuel under oxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Serrano-Purroy, D., E-mail: Daniel.serrano-purroy@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe (Germany); Casas, I. [Department of Chemical Engineering, UPC, Barcelona (Spain); González-Robles, E. [Environmental Technology Department, Fundació CTM Centre Tecnològic, Manresa, Barcelona (Spain); Glatz, J.P.; Wegen, D.H. [European Commission, Joint Research Centre, Institute for Transuranium Elements, Karlsruhe (Germany); Clarens, F. [Environmental Technology Department, Fundació CTM Centre Tecnològic, Manresa, Barcelona (Spain); Giménez, J. [Department of Chemical Engineering, UPC, Barcelona (Spain); Pablo, J. de [Department of Chemical Engineering, UPC, Barcelona (Spain); Environmental Technology Department, Fundació CTM Centre Tecnològic, Manresa, Barcelona (Spain); Martínez-Esparza, A. [High Level Waste Department, ENRESA, Empresa Nacional de Residuos Radioactivos, Madrid (Spain)

    2013-03-15

    The leaching of a high-burn-up spent nuclear fuel (48 MWd/KgU) has been studied in a carbonate-containing solution and under oxic conditions using a Continuously Stirred Tank Flow-Through Reactor (CSTR). Two samples of the fuel, one prepared from the centre of the pellet (labelled CORE) and another one from the fuel pellet periphery, enriched with the so-called High Burn-Up Structure (HBS, labelled OUT) have been used. For uranium and actinides, the results showed that U, Np, Am and Cm gave very similar normalized dissolution rates, while Pu showed slower dissolution rates for both samples. In addition, dissolution rates were consistently two to four times lower for OUT sample compared to CORE sample. Considering the fission products release the main results are that Y, Tc, La and Nd dissolved very similar to uranium; while Cs, Sr, Mo and Rb have up to 10 times higher dissolution rates. Rh, Ru and Zr seemed to have lower dissolution rates than uranium. The lowest dissolution rates were found for OUT sample. Three different contributions were detected on uranium release, modelled and attributed to oxidation layer, fines and matrix release.

  4. Catalytic Fuel Conversion Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility enables unique catalysis research related to power and energy applications using military jet fuels and alternative fuels. It is equipped with research...

  5. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  6. Optimization of fuel cells for BWR using Path Re linking and flexible strategies of solution;Optimizacion de celdas de combustible para BWR empleando Path Relinking y estrategias flexibles de solucion

    Energy Technology Data Exchange (ETDEWEB)

    Castillo M, J. A.; Ortiz S, J. J.; Torres V, M.; Perusquia del Cueto, R., E-mail: alejandro.castillo@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2009-10-15

    In this work are presented the obtained preliminary results to design nuclear fuel cells for boiling water reactors (BWR) using new strategies. To carry out the cells design some of the used rules in the fuel administration were discarded and other were implemented. The above-mentioned with the idea of making a comparative analysis between the used rules and those implemented here, under the hypothesis that it can be possible to design nuclear fuel cells without using all the used rules and executing the security restrictions that are imposed in these cases. To evaluate the quality of the obtained cells it was taken into account the power pick factor and the infinite multiplication factor, in the same sense, to evaluate the proposed configurations and to obtain the mentioned parameters was used the CASMO-4 code. To optimize the design it is uses the combinatorial optimization technique named Path Re linking and the Dispersed Search as local search method. The preliminary results show that it is possible to implement new strategies for the cells design of nuclear fuel following new rules. (Author)

  7. Final Report: Investigation of Catalytic Pathways for Lignin Breakdown into Monomers and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstein, Jeffrey A [ORNL; Hu, Michael Z. [ORNL; Kidder, Michelle [ORNL; McFarlane, Joanna [ORNL; Narula, Chaitanya Kumar [ORNL; Sturgeon, Matthew R [ORNL

    2010-12-01

    Lignin is a biopolymer that comprises up to 35% of woody biomass by dry weight. It is currently underutilized compared to cellulose and hemicellulose, the other two primary components of woody biomass. Lignin has an irregular structure of methoxylated aromatic groups linked by a suite of ether and alkyl bonds which makes it difficult to degrade selectively. However, the aromatic components of lignin also make it promising as a base material for the production of aromatic fuel additives and cyclic chemical feed stocks such as styrene, benzene, and cyclohexanol. Our laboratory research focused on three methods to selectively cleave and deoxygenate purified lignin under mild conditions: acidolysis, hydrogenation and electrocatalysis. (1) Acidolysis was undertaken in CH2Cl2 at room temperature. (2) Hydrogenation was carried out by dissolving lignin and a rhodium catalyst in 1:1 water:methoxyethanol under a 1 atm H2 environment. (3) Electrocatalysis of lignin involved reacting electrically generated hydrogen atoms at a catalytic palladium cathode with lignin dissolved in a solution of aqueous methanol. In all of the experiments, the lignin degradation products were identified and quantified by gas chromatography mass spectroscopy and flame ionization detection. Yields were low, but this may have reflected the difficulty in recovering the various fractions after conversion. The homogeneous hydrogenation of lignin showed fragmentation into monomers, while the electrocatalytic hydrogenation showed production of polyaromatic hydrocarbons and substituted benzenes. In addition to the experiments, promising pathways for the conversion of lignin were assessed. Three conversion methods were compared based on their material and energy inputs and proposed improvements using better catalyst and process technology. A variety of areas were noted as needing further experimental and theoretical effort to increase the feasibility of lignin conversion to fuels.

  8. Mathematical modeling of polymer electrolyte fuel cells

    Science.gov (United States)

    Sousa, Ruy; Gonzalez, Ernesto R.

    Fuel cells with a polymer electrolyte membrane have been receiving more and more attention. Modeling plays an important role in the development of fuel cells. In this paper, the state-of-the-art regarding modeling of fuel cells with a polymer electrolyte membrane is reviewed. Modeling has allowed detailed studies concerning the development of these cells, e.g. in discussing the electrocatalysis of the reactions and the design of water-management schemes to cope with membrane dehydration. Two-dimensional models have been used to represent reality, but three-dimensional models can cope with some important additional aspects. Consideration of two-phase transport in the air cathode of a proton exchange membrane fuel cell seems to be very appropriate. Most fuel cells use hydrogen as a fuel. Besides safety concerns, there are problems associated with production, storage and distribution of this fuel. Methanol, as a liquid fuel, can be the solution to these problems and direct methanol fuel cells (DMFCs) are attractive for several applications. Mass transport is a factor that may limit the performance of the cell. Adsorption steps may be coupled to Tafel kinetics to describe methanol oxidation and methanol crossover must also be taken into account. Extending the two-phase approach to the DMFC modeling is a recent, important point.

  9. Observation of water dangling OH bonds around dissolved nonpolar groups.

    Science.gov (United States)

    Perera, P N; Fega, K R; Lawrence, C; Sundstrom, E J; Tomlinson-Phillips, J; Ben-Amotz, Dor

    2009-07-28

    We report the experimental observation of water dangling OH bonds in the hydration shells around dissolved nonpolar (hydrocarbon) groups. The results are obtained by combining vibrational (Raman) spectroscopy and multivariate curve resolution (MCR), to reveal a high-frequency OH stretch peak arising from the hydration shell around nonpolar (hydrocarbon) solute groups. The frequency and width of the observed peak is similar to that of dangling OH bonds previously detected at macroscopic air-water and oil-water interfaces. The area of the observed peak is used to quantify the number of water dangling bonds around hydrocarbon chains of different length. Molecular dynamics simulation of the vibrational spectra of water molecules in the hydration shell around neopentane and benzene reveals high-frequency OH features that closely resemble the experimentally observed dangling OH vibrational bands around neopentyl alcohol and benzyl alcohol. The red-shift of approximately 50 cm(-1) induced by aromatic solutes is similar to that previously observed upon formation of a pi-H bond (in low-temperature benzene-water clusters).

  10. A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol.

    Science.gov (United States)

    Yuan, Zhaoyang; Wen, Yangbing; Kapu, Nuwan Sella; Beatson, Rodger; Mark Martinez, D

    2017-01-01

    Bamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel. An integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture

  11. Estuarine modification of dissolved and particulate trace metals in major rivers of East-Hainan, China

    Science.gov (United States)

    Fu, Jun; Tang, Xiao-Liang; Zhang, Jing; Balzer, Wolfgang

    2013-04-01

    Dissolved and particulate cadmium, copper, iron, lead, cobalt and nickel were analyzed in surface waters of the Wanquan River estuary and the Wenchang/Wenjiao River estuary in East-Hainan Island during the dry season (December 2006) and two wet seasons (August 2007 and July/August 2008). A major difference to other Chinese rivers was the very low concentration of suspended particles in these tropical Hainan estuaries. In the dissolved phase, a positive deviation from the theoretical dilution line was observed for Cd during different expeditions. Dissolved Cu and Ni essentially behaved conservatively, while Fe, Pb and partly also Co correlated in their negative deviation from simple mixing. Strong seasonal variability was observed only for dissolved Fe, Pb and Cd: sorption by the much higher loading with suspended particles during the dry season lead to a strong lowering of dissolved Fe and Pb, while the opposite was observed for dissolved Cd. In both estuaries all six metals in particulate form showed almost constant values with a tendency for slight decreases along the salinity profile. The normalization to particulate Al revealed some specific particle properties during the different expeditions. The dynamics of Fe chemistry dominated the distribution of Pb in all forms. The distribution coefficients KD showed a general decrease in the order Fe>Pb>Co>Ni>Cu≈Cd. There was no "particle concentration effect"; rather the KD's of Fe and Pb exhibited slightly positive correlations with the suspended particle loadings. Elevated concentrations levels in the Wenchang/Wenjiao river estuary, especially during the wet season 2008, were ascribed to diffuse inputs from aquaculture ponds which girdle the upper estuary. In comparison to major Chinese rivers, the tropical Hainan estuaries (S>0) showed similar levels for Cd, Cu, Pb, Co and Ni in particles and solution, while Fe was enriched in both matrices. On a global scale, neither in the Wanquan river estuary nor in the

  12. MOUTH DISSOLVING FILM AND THEIR PATENT: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Udhan Ravindra Radhakisan

    2012-09-01

    Full Text Available Now days the researchers are focusing on the fast dissolving dosage form (FDDF’s.The fast dissolving dosage forms includes the mouth dissolving tablets, mouth dissolving thin films .The alternative words used for these dosage forms are fast disintegrating, orodispersible, fast dissolving. The oral thin film technology (OTF’s is a dissolvable film technology have evolved from a purely confectionery novelty from a drug delivery platform. The OTH dosage form dissolves in the moth without need of water and within 10-15 seconds is the novelty of this dosage form. On the basis of this novelty many patents are available in the US country. Intraoral delivery is particularly beneficial to patients with special needs that are unable to tolerate traditional oral (entral/through GI track administration due to nausea, vomiting or dysphasia. Many pharmaceutical companies focusing on this Oral thin film technology. Today, this film technology is approved by is approved by FDA.

  13. Total dissolvable and dissolved iron isotopes in the water column of the Peru upwelling regime

    Science.gov (United States)

    Chever, Fanny; Rouxel, Olivier J.; Croot, Peter L.; Ponzevera, Emmanuel; Wuttig, Kathrin; Auro, Maureen

    2015-08-01

    Vertical distributions of iron (Fe) concentrations and isotopes were determined in the total dissolvable and dissolved pools in the water column at three coastal stations located along the Peruvian margin, in the core of the Oxygen Minimum Zone (OMZ). The shallowest station 121 (161 m total water depth) was characterized by lithogenic input from the continental plateau, yielding concentrations as high as 456 nM in the total dissolvable pool. At the 2 other stations (stations 122 and 123), Fe concentrations of dissolved and total dissolvable pools exhibited maxima in both surface and deep layers. Fe isotopic composition (δ56Fe) showed a fractionation toward lighter values for both physical pools throughout the water column for all stations with minimum values observed for the surface layer (between -0.64 and -0.97‰ at 10-20 m depth) and deep layer (between -0.03 and -1.25‰ at 160-300 m depth). An Fe isotope budget was established to determine the isotopic composition of the particulate pool. We observed a range of δ56Fe values for particulate Fe from +0.02 to -0.87‰, with lightest values obtained at water depth above 50 m. Such light values in the both particulate and dissolved pools suggest sources other than atmospheric dust deposition in the surface ocean, including lateral transport of isotopically light Fe. Samples collected at station 122 closest to the sediment show the lightest isotope composition in the dissolved and the particulate pools (-1.25 and -0.53‰ respectively) and high Fe(II) concentrations (14.2 ± 2.1 nM) consistent with a major reductive benthic Fe sources that is transferred to the ocean water column. A simple isotopic model is proposed to link the extent of Fe(II) oxidation and the Fe isotope composition of both particulate and dissolved Fe pools. This study demonstrates that Fe isotopic composition in OMZ regions is not only affected by the relative contribution of reductive and non-reductive shelf sediment input but also by

  14. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  15. Effect of Dissolved Organic Matter on Basalt Weathering Rates under Flow Conditions

    Science.gov (United States)

    Dontsova, K.; Steefel, C. I.; Chorover, J. D.

    2009-12-01

    Rock weathering is an important aspect of soil formation that is tightly coupled to the progressive colonization of grain surfaces by microorganisms and plant tissue, both of which are associated with the exudation of complexing ligands and reducing equivalents that are incorporated into dissolved organic matter. As part of a larger hillslope experimental study being designed for Biosphere 2 (Oracle, AZ), we seek to determine how the presence and concentration of dissolved organic matter affects the incongruent dissolution rates of basaltic tuff. Saturated flow column experiments are being conducted using plant-derived soluble organic matter solutions of variable concentrations, and comparisons are being made to experiments conducted with malic acid, a low-molecular weight organic acid commonly exuded into the rhizosphere. Dissolved organic matter was extracted from Ponderosa Pine forest floor and was characterized for aqueous geochemical parameters (pH, EC, ion balance, DOC/TN) and also for DOC composition (UV-Vis, FTIR spectroscopy). Column effluents are being analyzed for major and trace cations, anions, silica and organic solutes. Dissolution rates of primary minerals and precipitation rates of secondary phases will be estimated by fitting the data to a numerical reactive transport model, CrunchFlow2007. At the end of the fluid flow experiment, column materials will be analyzed for biogeochemical composition to detect preferential dissolution of specific phases, the precipitation of new ones, and to monitor the associated formation of biofilms. The influence of organic solutions on weathering patterns of basalt will be discussed.

  16. Role of Soil-derived Dissolved Substances in Arsenic Transport and Transformation in Laboratory Experiments

    Science.gov (United States)

    Chen, Zhangrong; Cai, Yong; Liu, Guangliang; Solo-Gabriele, Helena; Snyder, George H.; Cisar, John L.

    2011-01-01

    Dissolved substances derived from soil may interact with both soil surfaces and with arsenic and subsequently influence arsenic mobility and species transformation. The purpose of this study was to investigate arsenic transport and transformation in porous media with a specific focus on the impact of soil-derived dissolved substances, mainly consisting of inorganic colloids and dissolved organic matter (DOM), on these processes. Arsenic transport and transformation through columns, which were packed with uncoated sand (UC) or naturally coated sand (NC) and fed with arsenate (AsV) or monomethylarsonic acid (MMA) spiked influents, were investigated in the presence or absence of soil-derived dissolved substances. The presence of soil-derived inorganic colloids and/or DOM clearly enhanced As transport through the column, with the fraction of As leached out of column (referring to the total amount added) being increased from 23 to 46% (UC) and 21 to 50% (NC) in AsV experiments while 46 to 64% (UC) and 28 to 63% (NC) in MMA experiments. The association of arsenic with DOM and the competitive adsorption between arsenic and DOM could account for, at least partly, the enhanced As movement. Distinct species transformation of As during transport through soil columns was observed. When AsV was the initial species spiked in the influent solutions, only arsenite (AsIII) was detected in the effluents for UC columns; while both AsIII (dominant) and AsV were present for NC columns, with AsIII being the dominant species. When MMA was initially spiked in the influent solutions, all method detectable As species, AsIII, AsV, MMA, and dimethylarsenic acid (DMA) were present in the effluents for both soil columns. These results indicate that risk assessment associated with As contamination, particularly due to previous organoarsenical pesticide applications, should take into account the role of soil-derived dissolved substances in promoting As transport and As species transformation

  17. Role of soil-derived dissolved substances in arsenic transport and transformation in laboratory experiments.

    Science.gov (United States)

    Chen, Zhangrong; Cai, Yong; Liu, Guangliang; Solo-Gabriele, Helena; Snyder, George H; Cisar, John L

    2008-11-15

    Dissolved substances derived from soil may interact with both soil surfaces and with arsenic and subsequently influence arsenic mobility and species transformation. The purpose of this study was to investigate arsenic transport and transformation in porous media with a specific focus on the impact of soil-derived dissolved substances, mainly consisting of inorganic colloids and dissolved organic matter (DOM), on these processes. Arsenic transport and transformation through columns, which were packed with uncoated sand (UC) or naturally coated sand (NC) and fed with arsenate (AsV) or monomethylarsonic acid (MMA) spiked influents, were investigated in the presence or absence of soil-derived dissolved substances. The presence of soil-derived inorganic colloids and/or DOM clearly enhanced As transport through the column, with the fraction of As leached out of column (referring to the total amount added) being increased from 23 to 46% (UC) and 21 to 50% (NC) in AsV experiments while 46 to 64% (UC) and 28 to 63% (NC) in MMA experiments. The association of arsenic with DOM and the competitive adsorption between arsenic and DOM could account for, at least partly, the enhanced As movement. Distinct species transformation of As during transport through soil columns was observed. When AsV was the initial species spiked in the influent solutions, only arsenite (AsIII) was detected in the effluents for UC columns; while both AsIII (dominant) and AsV were present for NC columns, with AsIII being the dominant species. When MMA was initially spiked in the influent solutions, all method detectable As species, AsIII, AsV, MMA, and dimethylarsenic acid (DMA) were present in the effluents for both soil columns. These results indicate that risk assessment associated with As contamination, particularly due to previous organoarsenical pesticide applications, should take into account the role of soil-derived dissolved substances in promoting As transport and As species transformation.

  18. Mechatronics in fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Stefanopoulou, Anna G.; Kyungwon Suh [Mechanical Engineering Department, University of Michigan, 1231 Beal Avenue, Ann Arbor, MI 48109, (United States)

    2007-03-15

    Power generation from fuel cells (FCs) requires the integration of chemical, fluid, mechanical, thermal, electrical, and electronic subsystems. This integration presents many challenges and opportunities in the mechatronics field. This paper highlights important design issues and poses problems that require mechatronics solutions. The paper begins by describing the process of designing a toy school bus powered by hydrogen for an undergraduate student project. The project was an effective and rewarding educational activity that revealed complex systems issues associated with FC technology. (Author)

  19. The effect of fuel chemistry on UO2 dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Amanda; Hanson, Brady; Miller, William

    2016-08-01

    The dissolution rate of both unirradiated UO2 and used nuclear fuel has been studied by numerous countries as part of the performance assessment of proposed geologic repositories. In the scenario of waste package failure and groundwater infiltration into the fuel, the effects of variables such as temperature, dissolved oxygen, and water and fuel chemistry on the dissolution rates of the fuel are necessary to provide a quantitative estimate of the potential release over geologic time frames. The primary objective of this research was to determine the influence these parameters have on the dissolution rate of unirradiated UO2 under repository conditions and compare them to the rates predicted by current dissolution models. Both unirradiated UO2 and UO2 doped with varying concentrations of Gd2O3, to simulate used fuel composition after long time periods where radiolysis has minor contributions to dissolution, were examined. In general, a rise in temperature increased the dissolution rate of UO2 and had a larger effect on pure UO2 than on those doped with Gd2O3. Oxygen dependence was observed in the UO2 samples with no dopant and increased as the temperature rose; in the doped fuels less dependence was observed. The addition of gadolinia into the UO2 matrix showed a significant decrease in the dissolution rate. The matrix stabilization effect resulting from the dopant proved even more beneficial in lowering the dissolution rate at higher temperatures and dissolved O2 concentrations in the leachate where the rates would typically be elevated.

  20. Fuel System Compatibility Issues for Prometheus-1

    Energy Technology Data Exchange (ETDEWEB)

    DC Noe; KB Gibbard; MH Krohn

    2006-01-20

    Compatibility issues for the Prometheus-1 fuel system have been reviewed based upon the selection of UO{sub 2} as the reference fuel material. In particular, the potential for limiting effects due to fuel- or fission product-component (cladding, liner, spring, etc) chemical interactions and clad-liner interactions have been evaluated. For UO{sub 2}-based fuels, fuel-component interactions are not expected to significantly limit performance. However, based upon the selection of component materials, there is a potential for degradation due to fission products. In particular, a chemical liner may be necessary for niobium, tantalum, zirconium, or silicon carbide-based systems. Multiple choices exist for the configuration of a chemical liner within the cladding; there is no clear solution that eliminates all concerns over the mechanical performance of a clad/liner system. A series of tests to evaluate the performance of candidate materials in contact with real and simulated fission products is outlined.

  1. Liquid fuel utilization in SOFC hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Santin, Marco; Traverso, Alberto; Magistri, Loredana [TPG-DIMSET, University of Genoa, Via Montallegro 1, 16145 Genoa (Italy)

    2009-10-15

    The interest in solid oxide fuel cell systems comes from their capability of converting the chemical energy of traditional fuels into electricity, with high efficiency and low pollutant emissions. In this paper, a study of the design space of solid oxide fuel cell and gas turbine hybrids fed by methanol and kerosene is presented for stationary power generation in isolated areas (or transportation). A 500 kW class hybrid system was analysed using WTEMP original software developed by the Thermochemical Power Group of the University of Genoa. The choice of fuel-processing strategy and the influence of the main design parameters on the thermoeconomic characteristics of hybrid systems were investigated. The low capital and fuel cost of methanol systems make them the most attractive solutions among those investigated here. (author)

  2. Selection of Fuel by Using Analytical Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Asilata M. Damle,

    2015-04-01

    Full Text Available Selection of fuel is a very important and critical decision one has to make. Various criteria are to be considered while selecting a fuel. Some of important criteria are Fuel Economy, Availability of fuel, Pollution from vehicle, Maintenance of the vehicle. Selection of best fuel is a complex situation. It needs a multi-criteria analysis. Earlier, the solution to the problem were found by applying classical numerical methods which took into account only technical and economic merits of the various alternatives. By applying multi-criteria tools, it is possible to obtain more realistic results. This paper gives a systematic analysis for selection of fuel by using Analytical Hierarchy Process (AHP. This is a multi-criteria decision making process. By using AHP we can select the fuel by comparing various factors in a mathematical model. This is a scientific method to find out the best fuel by making pairwise comparisons.

  3. An integrated multicriteria decision-making approach for evaluating nuclear fuel cycle systems for long-term sustainability on the basis of an equilibrium model: Technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory combined with analytic hierarchy process

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sae Rom [Dept of Quantum Energy Chemical Engineering, Korea University of Science and Technology (KUST), Daejeon (Korea, Republic of); Choi, Sung Yeol [Ulsan National Institute of Science and Technology, Ulju (Korea, Republic of); Ko, Wonil [Nonproliferation System Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

  4. An Integrated Multicriteria Decision-Making Approach for Evaluating Nuclear Fuel Cycle Systems for Long-term Sustainability on the Basis of an Equilibrium Model: Technique for Order of Preference by Similarity to Ideal Solution, Preference Ranking Organization Method for Enrichment Evaluation, and Multiattribute Utility Theory Combined with Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Saerom Yoon

    2017-02-01

    Full Text Available The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

  5. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  6. Dissolved Organic Nitrogen in Mediterranean Ecosystems

    Institute of Scientific and Technical Information of China (English)

    M.DELGADO-BAQUERIZO; F.COVELO; A.GALLARDO

    2011-01-01

    Dissolved organic nitrogen (DON) in soils has recently gained increasing interest because it may be both a direct N source for plants and the dominant available N form in nutrient-poor soils, however, its prevalence in Mediterranean ecosystems remains unclear. The aims of this study were to i) estimate soil DON in a wide set of Mediterranean ecosystems and compare this levels with those for other ecosystems; ii) describe temporal changes in DON and dissolved inorganic nitrogen (DIN) forms (NH4+ and NO3-), and characterize spatial heterogeneity within plant communities; and iii) study the relative proportion of soil DON and DIN forms as a test of Schimel and Bennett's hypothesis that the prevalence of different N forms follows a gradient of nutrient availability. The study was carried out in eleven plant communities chosen to represent a wide spectrum of Mediterranean vegetation types, ranging from early to late successional status. DON concentrations in the studied Mediterranean plant communities (0-18.2 mg N kg-1) were consistently lower than those found in the literature for other ecosystems. We found high temporal and spatial variability in soil DON for all plant communities. As predicted by the Schimel and Bennett model for nutrient-poor ecosystems, DON dominance over ammonium and nitrate was observed for most plant communities in winter and spring soil samples. However, mineral-N dominated over DON in summer and autumn. Thus, soil water content may have an important effect on DON versus mineral N dominance in Mediterranean ecosystems.

  7. Modeling the Thermal Rocket Fuel Preparation Processes in the Launch Complex Fueling System

    Directory of Open Access Journals (Sweden)

    A. V. Zolin

    2015-01-01

    Full Text Available It is necessary to carry out fuel temperature preparation for space launch vehicles using hydrocarbon propellant components. A required temperature is reached with cooling or heating hydrocarbon fuel in ground facilities fuel storages. Fuel temperature preparing processes are among the most energy-intensive and lengthy processes that require the optimal technologies and regimes of cooling (heating fuel, which can be defined using the simulation of heat exchange processes for preparing the rocket fuel.The issues of research of different technologies and simulation of cooling processes of rocket fuel with liquid nitrogen are given in [1-10]. Diagrams of temperature preparation of hydrocarbon fuel, mathematical models and characteristics of cooling fuel with its direct contact with liquid nitrogen dispersed are considered, using the numerical solution of a system of heat transfer equations, in publications [3,9].Analytical models, allowing to determine the necessary flow rate and the mass of liquid nitrogen and the cooling (heating time fuel in specific conditions and requirements, are preferred for determining design and operational characteristics of the hydrocarbon fuel cooling system.A mathematical model of the temperature preparation processes is developed. Considered characteristics of these processes are based on the analytical solutions of the equations of heat transfer and allow to define operating parameters of temperature preparation of hydrocarbon fuel in the design and operation of the filling system of launch vehicles.The paper considers a technological system to fill the launch vehicles providing the temperature preparation of hydrocarbon gases at the launch site. In this system cooling the fuel in the storage tank before filling the launch vehicle is provided by hydrocarbon fuel bubbling with liquid nitrogen. Hydrocarbon fuel is heated with a pumping station, which provides fuel circulation through the heat exchanger-heater, with

  8. Riverine Dissolved Organic Matter Degradation Modeled Through Microbial Incubations of Vascular Plant Leachates

    Science.gov (United States)

    Harfmann, J.; Hernes, P.; Chuang, C. Y.

    2015-12-01

    Dissolved organic matter (DOM) contains as much carbon as is in the atmosphere, provides the main link between terrestrial and marine carbon reservoirs, and fuels the microbial food web. The fate and removal of DOM is a result of several complex conditions and processes, including photodegradation, sorption/desorption, dominant vascular plant sources, and microbial abundance. In order to better constrain factors affecting microbial degradation, laboratory incubations were performed using Sacramento River water for microbial inoculums and vascular plant leachates. Four vascular plant sources were chosen based on their dominance in the Sacramento River Valley: gymnosperm needles from Pinus sabiniana (foothill pine), angiosperm dicot leaves from Quercus douglassi (blue oak), angiosperm monocot mixed annual grasses, and angiosperm monocot mixed Schoenoplectus acutus (tule) and Typha spp. (cattails). Three concentrations of microbial inoculum were used for each plant material, ranging from 0.2% to 10%. Degradation was monitored as a function of time using dissolved organic carbon (DOC), UV-Vis absorbance, and fluorescent dissolved organic matter (fDOM), and was compared across vascular plant type and inoculum concentration.

  9. Relevance of peat-draining rivers for the riverine input of dissolved iron into the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Krachler, Regina, E-mail: regina.krachler@univie.ac.at [Institute of Inorganic Chemistry, University of Vienna, Waehringerstrasse 42, 1090 Vienna (Austria); Krachler, Rudolf F. [Institute of Inorganic Chemistry, University of Vienna, Waehringerstrasse 42, 1090 Vienna (Austria); Kammer, Frank von der; Suephandag, Altan [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria); Jirsa, Franz; Ayromlou, Shahram [Institute of Inorganic Chemistry, University of Vienna, Waehringerstrasse 42, 1090 Vienna (Austria); Hofmann, Thilo [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria); Keppler, Bernhard K. [Institute of Inorganic Chemistry, University of Vienna, Waehringerstrasse 42, 1090 Vienna (Austria)

    2010-05-01

    Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's biological productivity and biological carbon pump, but understanding this role is constrained by inconsistent observations regarding the behaviour of riverine iron in the estuarine mixing zone, where precipitation reactions remove iron from the water column. We applied a characterization of the colloidal iron carriers in peatland-draining rivers in North Scotland, using field-flow fractionation (FFF), in combination with end-member mixing experiments of river water sampled near the river mouth and coastal seawater using a {sup 59}Fe radiotracer method. According to our results, the investigated river contributed 'truly dissolved' Fe concentrations of about 3300 nmol L{sup -1} to the ocean which is nearly two orders of magnitude higher than the dissolved iron contribution of the 'average world' river ({approx} 40 nmol L{sup -1}). Thus we conclude that peatland-draining rivers are important sources of dissolved iron to the ocean margins. We propose highly electrostatic and sterical stabilized iron-organic matter complexes in the size range of < 2 kDa to be responsible for iron transport across the estuarine mixing zone.

  10. Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Science.gov (United States)

    Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

    2016-05-03

    A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  11. Black Carbon in Estuarine (Coastal) High-molecular-weight Dissolved Organic Matter

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Dissolved organic matter (DOM) in the ocean constitutes one of the largest pools of organic carbon in the biosphere, yet much of its composition is uncharacterized. Observations of black carbon (BC) particles (by-products of fossil fuel combustion and biomass burning) in the atmosphere, ice, rivers, soils and marine sediments suggest that this material is ubiquitous, yet the contribution of BC to the ocean s DOM pool remains unknown. Analysis of high-molecular-weight DOM isolated from surface waters of two estuaries in the northwest Atlantic Ocean finds that BC is a significant component of DOM, suggesting that river-estuary systems are important exporters of BC to the ocean through DOM. We show that BC comprises 4-7% of the dissolved organic carbon (DOC) at coastal ocean sites, which supports the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition. Flux calculations suggest that BC could be as important as vascular plant-derived lignin in terms of carbon inputs to the ocean. Production of BC sequesters fossil fuel- and biomass-derived carbon into a refractory carbon pool. Hence, BC may represent a significant sink for carbon to the ocean.

  12. HTGR fuel and fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Lotts, A.L.; Coobs, J.H.

    1976-08-01

    The status of fuel and fuel cycle technology for high-temperature gas-cooled reactors (HTGRs) is reviewed. The all-ceramic core of the HTGRs permits high temperatures compared with other reactors. Core outlet temperatures of 740/sup 0/C are now available for the steam cycle. For advanced HTGRs such as are required for direct-cycle power generation and for high-temperature process heat, coolant temperatures as high as 1000/sup 0/C may be expected. The paper discusses the variations of HTGR fuel designs that meet the performance requirements and the requirements of the isotopes to be used in the fuel cycle. Also discussed are the fuel cycle possibilities, which include the low-enrichment cycle, the Th-/sup 233/U cycle, and plutonium utilization in either cycle. The status of fuel and fuel cycle development is summarized.

  13. Improvement of the cold flow characteristics of biodiesel containing dissolved polymer wastes using acetone

    Directory of Open Access Journals (Sweden)

    Pouya Mohammadi

    2014-03-01

    Full Text Available Due to the fast fossil fuel depletion and at the same time global warming phenomenon anticipated for the next coming years, the necessity of developing alternative fuels e.g. biofuels (i.e. bioethanol, biodiesel, biogas and etc. has turned into an important concern. Recently, the application of the bio-solvency properties of biodiesel for recycling waste polymers has been highlighted. However, the impact of polymer dissolution on cold flow characteristics of biodiesel was never investigated. The present study was set to explore the impact of different solvents in stabilizing biodiesel-polymer solution. Among them, acetone was proved to be the best fuel stabilizer. Subsequently, cold flow characteristic i.e. cloud point, of the biodiesel-polymer-acetone fuel was found to have improved (decreased due to the inclusion of acetone. Finally, flash point analysis of the fuel blends containing acetone was done to ensured high safety of the fuel blend by dramatically increasing the flash point values of biodiesel-polymer fuel blends.

  14. Effects of Fe(II) and hydrogen peroxide interaction upon dissolving UO2 under geologic repository conditions.

    Science.gov (United States)

    Amme, M; Bors, W; Michel, C; Stettmaier, K; Rasmussen, G; Betti, M

    2005-01-01

    Iron redox cycling is supposed to be one of the major mechanisms that control the geochemical boundary conditions in the near field of a geologic repository for UO2 spent nuclear fuel. This work investigates the impact of reactions between hydrogen peroxide (H2O2) and iron (Fe2+/Fe3+) on UO2 dissolution. The reaction partners were contacted with UO2 in oxygen-free batch reactor tests. The interaction in absence of UO2 gives a stoichiometric redox reaction of Fe2+ and H2O2 when the reactants are present in equal concentration. Predomination of H202 results in its delayed catalytic decomposition. With UO2 present, its dissolution is controlled by either a slow mechanism (as typical for anoxic environments) or uranium peroxide precipitation, depending strongly on the reactant ratio. Uranium peroxide (UO4 x nH2O, m-studtite), detected on UO2 surfaces after exposure to H2O2, was not found on the surfaces exposed to solutions with stoichometric Fe(II)/ H2O2 ratios. This suggests that H2O2 was deactivated in redox reactions before a formation of UO4 took place. ESR measurements employing the spin trapping technique revealed only the DMPO-OH adduct within the first minutes after the reaction start (high initial concentrations of the OH radical); however, in the case of Fe(II) and H2O2 reacting at 10(-4) mol/L with UO2, dissolved oxygen and Fe2+ concentrations indicate the participation of further Fe intermediates and, therefore, Fenton redox activities.

  15. Fast dissolving strips: A novel approach for the delivery of verapamil

    Directory of Open Access Journals (Sweden)

    S Kunte

    2010-01-01

    Full Text Available Objective: Fast dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules etc. Verapamil is a calcium channel blocker used as an antianginal, antiarrhythmic, and antihypertensive agent with extensive first pass metabolism which results in less bioavailability. This work investigated the possibility of developing verapamil fast dissolving strips allowing fast, reproducible drug dissolution in the oral cavity; thus bypassing first pass metabolism. Materials and methods: The fast dissolving strips were prepared by solvent casting technique with the help of HPMC E6 and maltodextrin. The strips were evaluated for drug content uniformity, film thickness, folding endurance, in vitro disintegration time, in vitro dissolution studies, surface pH study, and palatability study. Results: Official criteria for evaluation parameters were fulfilled by all formulations. Disintegration time showed by formulations was found to be in range of 20.4-28.6 sec. Based on the evaluation parameters, the formulation containing 2% HPMC E6 and 3.5% maltodextrin showed optimum performance against other formulations. Conclusion: It was concluded that the fast dissolving strips of verapamil can be made by solvent casting technique with enhanced dissolution rate, taste masking, and hence better patient compliance and effective therapy

  16. Thermo-chemical extraction of fuel oil from waste lubricating grease.

    Science.gov (United States)

    Pilusa, Tsietsi Jefrey; Muzenda, Edison; Shukla, Mukul

    2013-06-01

    This study investigated the recovery of oil from waste grease through the process of thermal degradation in an aqueous solution of potassium hydroxide (KOH) followed by solvent extraction. Waste high temperature metal bearing grease was dissolved in a 15 w/w% KOH solution at 80°C while being agitated at 2000 rpm using a shear action agitator for a period of 15 min. Two distinct layers were observed after 8 min of settling time. The top layer being of dark brown oil and the bottom layer was a heterogeneous mixture. The two layers were separated by decantation. The bottom layer was cooled down to 45°C followed by slow addition of toluene (C7H8) while agitating at 1200 rpm for 15 min to prevent solids settling and minimise rapid volatilisation of the organic compounds in the mixture. Two distinct layers were also formed, the top homogeneous mixture of light brown oil-toluene mixture and the bottom sludge layer. The solvent was recovered from the oil for re-use by fractional distillation of the homogenous mixture. It was observed that 15 w/w% potassium hydroxide solution can chemically degrade the soap matrix in the grease and extract up to 49 w/w% of the fuel oil when subjected to high shear stress at a temperature of 80°C. The 26 w/w% extraction of oil in the remaining sludge was obtained by solvent extraction process with mass ratios of sludge to solvent of 2:1. Solvent recovery of 88% by mass was obtained via fractional distillation method. The combined extraction processes brought an overall oil yield of 75 w/w% from the waste grease. The fuel oil obtained from this process has similar properties to paraffin oil and can be blended with other oils as an alternative energy source.

  17. Influence of dissolved hydrogen on the fatigue crack growth behaviour of AISI 4140 steel

    Science.gov (United States)

    Ramasagara Nagarajan, Varun

    Many metallic structural components come into contact with hydrogen during manufacturing processes or forming operations such as hot stamping of auto body frames and while in service. This interaction of metallic parts with hydrogen can occur due to various reasons such as water molecule dissociation during plating operations, interaction with atmospheric hydrogen due to the moisture present in air during stamping operations or due to prevailing conditions in service (e.g.: acidic or marine environments). Hydrogen, being much smaller in size compared to other metallic elements such as Iron in steels, can enter the material and become dissolved in the matrix. It can lodge itself in interstitials locations of the metal atoms, at vacancies or dislocations in the metallic matrix or at grain boundaries or inclusions (impurities) in the alloy. This dissolved hydrogen can affect the functional life of these structural components leading to catastrophic failures in mission critical applications resulting in loss of lives and structural component. Therefore, it is very important to understand the influence of the dissolved hydrogen on the failure of these structural materials due to cyclic loading (fatigue). For the next generation of hydrogen based fuel cell vehicles and energy systems, it is very crucial to develop structural materials for hydrogen storage and containment which are highly resistant to hydrogen embrittlement. These materials should also be able to provide good long term life in cyclic loading, without undergoing degradation, even when exposed to hydrogen rich environments for extended periods of time. The primary focus of this investigation was to examine the influence of dissolved hydrogen on the fatigue crack growth behaviour of a commercially available high strength medium carbon low alloy (AISI 4140) steel. The secondary objective was to examine the influence of microstructure on the fatigue crack growth behaviour of this material and to determine the

  18. Analysis of an homogeneous solution reactor for {sup 99} Mo production; Analisis de un reactor de solucion homogenea para produccion de {sup 99} Mo

    Energy Technology Data Exchange (ETDEWEB)

    Weir, A.; Lopasso, E.; Gho, C. [Departamento de Ingenieria Nuclear, Comision Nacional de Energia Atomica, Av. Bustillo 9500 Centro Atomico Bariloche, 8400 (Argentina)]. e-mail: weira@ib.cnea.gov.ar

    2007-07-01

    The {sup 99m} Tc is the more used radioisotope in nuclear medicine, used in 80% of procedures of nuclear medicine in the world. This is due to their characteristics practically ideal for the diagnostic. The {sup 99m}Tc is obtained by decay of the {sup 99}Mo, which can produce it by irradiating enriched targets in {sup 98}Mo, or as fission product, irradiating uranium targets or by means of homogeneous solution reactors. The pattern of the used reactor in the neutron analysis possesses a liquid fuel composed of uranyl nitrate dissolved in water with the attach of nitric acid. This solution is contained in a cylindrical recipient of stainless steel reflected with light water. The reactor is refrigerated by means of an helicoidal heat exchanger immersed in the fuel solution. The heat of the fuel is removed by natural convection while the circulation of the water inside the exchanger is forced. The control system of the reactor consists on 6 independent cadmium bars, with followers of water. An auxiliary control system can be the level of the fuel solution inside container tank, but it was not included in the pattern in study. One studies the variations of the reactivity of the system due to different phenomena. An important factor during the normal operation of the reactor is the variation of temperature taking to a volumetric expansion of the fuel and ghastly effects in the same one. Another causing phenomenon of changes in the reactivity is the variation of the concentration of uranium in the combustible solution. An important phenomenon in this type of reactors is the hole fraction in the nucleus I liquidate due to the radiolysis and the possible boil of the water of the combustible solution. Some of the possible cases of abnormal operation were studied as the lost one of coolant in the secondary circuit of the heat exchanger, the introduction and evaporation of water in the nucleus. The reactivity variations were studied using the codes of I calculate MCNP, WIMS

  19. Organic fuel cell methods and apparatus

    Science.gov (United States)

    Vamos, Eugene (Inventor); Surampudi, Subbarao (Inventor); Narayanan, Sekharipuram R. (Inventor); Frank, Harvey A. (Inventor); Halpert, Gerald (Inventor); Olah, George A. (Inventor); Prakash, G. K. Surya (Inventor)

    2008-01-01

    A liquid organic, fuel cell is provided which employs a solid electrolyte membrane. An organic fuel, such as a methanol/water mixture, is circulated past an anode of a cell while oxygen or air is circulated past a cathode of the cell. The cell solid electrolyte membrane is preferably fabricated from Nafion.TM.. Additionally, a method for improving the performance of carbon electrode structures for use in organic fuel cells is provided wherein a high surface-area carbon particle/Teflon.TM.-binder structure is immersed within a Nafion.TM./methanol bath to impregnate the electrode with Nafion.TM.. A method for fabricating an anode for use in a organic fuel cell is described wherein metal alloys are deposited onto the electrode in an electro-deposition solution containing perfluorooctanesulfonic acid. A fuel additive containing perfluorooctanesulfonic acid for use with fuel cells employing a sulfuric acid electrolyte is also disclosed. New organic fuels, namely, trimethoxymethane, dimethoxymethane, and trioxane are also described for use with either conventional or improved fuel cells.

  20. From waste to traffic fuel (W-fuel)

    Energy Technology Data Exchange (ETDEWEB)

    Kask, Ue.; Andrijevskaja, J.; Kask, L. [and others

    2012-11-01

    The EU directive on the promotion of the use of energy from renewable sources (Directive 2009/28/EC) sets a mandatory minimum target for the use of fuels produced using renewable energy sources of 10% of total petrol and diesel consumption in the transport sector by the year 2020. In addition, it states that production of renewable fuels should be consistent with sustainable development and must not endanger biodiversity. In the INTERREG IVA Southern Finland - Estonia Sub-programme, efforts towards finding solutions to the tasks set by the EU were undertaken in co-operation with Finnish and Estonian researchers. The purpose of the 'From Waste to Traffic Fuel' (W-Fuel) project was to promote the sustainable production and use of biogas using locally-sourced biodegradable waste materials from the food and beverage industry and the agricultural and municipal sectors. The ultimate aim of the project was to upgrade the biogas (produced based on anaerobic digestion of biodegradable wastes, sludge, manure, slurry and energy crops) to biomethane with a methane content similar to natural gas, to be further used as transport fuel with the aim of reducing traffic-borne emissions, in particular CO{sub 2}. The project combined waste, energy and traffic solutions in order to decrease emissions, costs and the use of materials. Six case areas in southern Finland and northern Estonia were selected. The two case areas in Estonia were the counties of Harju and Laeaene-Viru in northern Estonia. The project aimed to promote waste and sludge prevention and to commence biogas production and its subsequent upgrading to biomethane for use as a renewable fuel. The project promoted regional businesses and employment in waste treatment and 'green energy' production. On basis of the gathered data, the biogas potentials and prerequisites of each case county were analysed. Furthermore, the environmental, economic and other regional effects of the different options were

  1. Critical assessment of power trains with fuel-cell systems and different fuels

    Science.gov (United States)

    Höhlein, B.; von Andrian, S.; Grube, Th; Menzer, R.

    Legal regulations (USA, EU) are a major driving force for intensifying technological developments with respect to the global automobile market. In the future, highly efficient vehicles with very low emission levels will include low-temperature fuel-cell systems (PEFC) as units of electric power trains. With alcohols, ether or hydrocarbons used as fuels for these new electric power trains, hydrogen as PEFC fuel has to be produced on board. These concepts including the direct use of methanol in fuel-cell systems, differ considerably in terms of both their development prospects and the results achieved so far. Based on process engineering analyses for net electricity generation in PEFC-powered power trains, as well as on assumptions for electric power trains and vehicle configurations, different fuel-cell performances and fuel processing units for octane, diesel, methanol, ethanol, propane and dimethylether have been evaluated as fuels. The possible benefits and key challenges for different solutions of power trains with fuel-cell systems/on-board hydrogen production and with direct methanol fuel-cell (DMFC) systems have been assessed. Locally, fuel-cell power trains are almost emission-free and, unlike battery-powered vehicles, their range is comparable to conventional vehicles. Therefore, they have application advantages cases of particularly stringent emission standards requiring zero emission. In comparison to internal combustion engines, using fuel-cell power trains can lead to clear reductions in primary energy demand and global, climate-relevant emissions providing the advantage of the efficiency of the hydrogen/air reaction in the fuel cell is not too drastically reduced by additional conversion steps of on-board hydrogen production, or by losses due to fuel supply provision.

  2. Dissolved Black Carbon in the Southern Ocean along CLIVAR section I6S

    Science.gov (United States)

    Paeng, J.; Dittmar, T.

    2008-12-01

    Thermogenic matter ("black carbon", BC) is abundant in the environment. BC is produced during catagenesis in earth's crust and is also a residue of fossil fuel and biomass burning. Because of its refractory character, BC accumulates in soils and sediments and sequesters carbon from active cycles. Previous studies found indications that BC might be a significant component also in marine dissolved organic matter (DOM). However, the available information on black carbon in DOM is extremely rare up to now. The objective of this study is to quantify BC in marine DOM and identify the source and dynamics of dissolved BC for a major oceanic region. Detailed depth profiles were sampled along 30º E from South Africa to Antarctica at 1º intervals on CLIVAR section I6S. Dissolved BC was isolated from approximately 250 seawater samples via a new solid phase extraction method. Fused aromatic ring systems as a molecular tracer for BC were quantified in these samples. For this purpose, the samples were oxidized with nitric acid and the reaction products of fused ring systems analyzed as benzene-polycarboxylic acids with HPLC. BC concentrations were very stable throughout the water column and along the North-South section, ranging between 500 and 700 nM BC. The molecular composition of benzene-polycarboxylic acids indicates a relatively small number of fused aromatic rings per molecule. Similar structures were observed preciously in riverine and also petroleum-derived DOM. The homogenous distribution of BC in all water masses indicates conservative behavior of BC in the ocean, and turnover rates which are far longer than oceanic turnover rates. The stable character of dissolved BC and its abundance in the ocean has major implications for our understanding of global biogeochemical cycles.

  3. FORMULATION AND EVALUATION OF FAST DISSOLVING FILMS OF ZOLMITRIPTAN

    OpenAIRE

    2012-01-01

    The present study was aimed to formulate and evaluate fast dissolving films of Zolmitriptan using hydroxyl propyl methyl cellulose. 5-HT1B and 5-HT1D antagonist which is an antimigraine. Hydroxyl propyl methyl cellulose is used as film forming agent. Fast dissolving films are meant to be dissolved in saliva and remain in oral cavity until swallowed. Hence taste masking becomes critically important. The films are prepared by solvent evaporation method and characterized by UV, FTIR studies. The...

  4. Study of Dissolved Chlorofluorocarbons in Lake Washington

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Measurements of three chlorofluorocarbons (CFCs): trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12) and trichlorotrifluoroethane (CFC 113), along with methyl chloroform (CH3CCl3) and carbon tetrachloride (CCl4) were made in water samples from Lake Washington, using Electron Capture Gas Chromatography (EC GC). The samples were collected in mid autumn, a period when the lake's upper layer undergoes rapid cooling. At the time of sampling, a strong vertical temperature gradient was present in the lake, with surface temperatures of ~14℃, and near bottom (50 meters) temperatures of ~8℃. The concentrations of dissolved CFC 12 and CFC 11 increased with depth, as expected from the higher solubilities of these gases at lower temperatures. Atmospheric measurements made at the sampling site at the time of the cruise, showed that CFC 11 and CFC 12 saturations in the near surface samples were 100 % and 106%, respectively. For the deepest sample (52 meters) CFC 11 and CFC 12 saturations were 102 % and 126 %. Because the surface layer of the lake responds to changes in atmospheric CFCs on a time scale of several weeks, the higher than equilibrium concentrations of CFC 12 observed at the time of sampling may reflect earlier episodes of elevated levels of atmospheric CFC 12 in this urban area. High concentrations of dissolved CFCs in runoff or industrial effluent might also lead to elevated CFC levels in the lake. The cold, deep water of Lake Washington is relatively isolated from the effects of surface gas exchange except during winter, and the supersaturations observe in the deep layer may reflect periods of elevated atmospheric CFC 12 levels from the previous winter season. These results were compared to summertime profiles of CFC 11 and CFC 12 made in 1994.

  5. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot

    2005-07-13

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

  6. Study on Electrospinning Silk Fibroin Solution

    Institute of Scientific and Technical Information of China (English)

    LI Ni; QIN Xiao-hong; WANG Shan-yuan

    2007-01-01

    A new method of preparing silk fibroin (SF) solution used in the electerospinning was introduced in this paper. According to the method, SF was dissolved in the LiBr/CH2O2 solution directly at room temperature. The method was compared with the traditional method---SF was dissolved in CaCl2 ternary solution. The structure of SF films and the morphology of SF nanofibers were examined by attenuated total reflectance fourier transform intrared (ATR- FrlR) spectroscopy, Scanning electron microscope (SEM) and optical polarizing microscope. The result of this study shows that the new method is a faster, more convenient and high efficient way to get the SF solution and the characteristics of SF fibet made by the new method is much betty.

  7. Role of dissolved oxygen reduction in improvement inhibition performance of ascorbic acid during copper corrosion in 0.50 mol/L sulphuric acid

    Institute of Scientific and Technical Information of China (English)

    Mohammed; A.Amin

    2010-01-01

    The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbi...

  8. Analisis Total Zat Padat Terlarut (Total Dissolved Solid) Dan Total Zat Padat Trsuspensi (Total Suspended Solid) Pada Air Badan Air Khususnya Air Sungai

    OpenAIRE

    Saraswaty, Asri

    2015-01-01

    Total dissolved solids ( Total Dissolved Solid ) is a measure of the solute( both organic and inorganic , for example : salt , etc.) contained in the river water. The total suspended solids (Total Suspended Solid) are solids that are in suspension , can be distinguished according to their size as suspended colloidal particles (colloidal particles) and particles suspended regular (suspended particles). The purpose of to determine whether the water meets the river that were analyzed in accordan...

  9. Proliferation Resistant Nuclear Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gray, L W; Moody, K J; Bradley, K S; Lorenzana, H E

    2011-02-18

    Global appetite for fission power is projected to grow dramatically this century, and for good reason. Despite considerable research to identify new sources of energy, fission remains the most plentiful and practical alternative to fossil fuels. The environmental challenges of fossil fuel have made the fission power option increasingly attractive, particularly as we are forced to rely on reserves in ecologically fragile or politically unstable corners of the globe. Caught between a globally eroding fossil fuel reserve as well as the uncertainty and considerable costs in the development of fusion power, most of the world will most likely come to rely on fission power for at least the remainder of the 21st century. Despite inevitable growth, fission power faces enduring challenges in sustainability and security. One of fission power's greatest hurdles to universal acceptance is the risk of potential misuse for nefarious purposes of fissionable byproducts in spent fuel, such as plutonium. With this issue in mind, we have discussed intrinsic concepts in this report that are motivated by the premise that the utility, desirability, and applicability of nuclear materials can be reduced. In a general sense, the intrinsic solutions aim to reduce or eliminate the quantity of existing weapons usable material; avoid production of new weapons-usable material through enrichment, breeding, extraction; or employ engineering solutions to make the fuel cycle less useful or more difficult for producing weapons-usable material. By their nature, these schemes require modifications to existing fuel cycles. As such, the concomitants of these modifications require engagement from the nuclear reactor and fuel-design community to fully assess their effects. Unfortunately, active pursuit of any scheme that could further complicate the spread of domestic nuclear power will probably be understandably unpopular. Nevertheless, the nonproliferation and counterterrorism issues are paramount

  10. HTGR Fuel performance basis

    Energy Technology Data Exchange (ETDEWEB)

    Shamasundar, B.I.; Stansfield, O.M.; Jensen, D.D.

    1982-05-01

    The safety characteristics of the high-temperature gas-cooled reactor (HTGR) during normal and accident conditions are determined in part by HTGR fuel performance. During normal operation, less than 0.1% fuel failure occurs, primarily from defective particles. This low fuel failure fraction limits circulating activity to acceptable levels. During severe accidents, the radiological consequence is influenced by high-temperature fuel particle behavior. An empirical fuel failure model, supported by recent experimental data, is presented. The onset of significant fuel particle failure occurs at temperatures in excess of 1600/sup 0/C, and complete fuel failure occurs at 2660/sup 0/C. This indicates that the fuel is more retentive at higher temperatures than previously assumed. The more retentive nature of the fuel coupled with the high thermal capacitance of the core results in slow release of fission products from the core during severe accidents.

  11. Pyrolysis oil as diesel fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gros, S. [Wartsila Diesel International Ltd., Vaasa (Finland). Diesel Technology

    1996-12-31

    Wood waste pyrolysis oil is an attractive fuel alternative for diesel engine operation. The main benefit is the sustainability of the fuel. No fossil reserves are consumed. The fact that wood waste pyrolysis oil does not contribute to CO{sub 2} emissions is of utmost importance. This means that power plants utilising pyrolysis oil do not cause additional global warming. Equally important is the reduced sulphur emissions that this fuel alternative implies. The sulphur content of pyrolysis oil is extremely low. The high water content and low heating value are also expected to result in very low NO{sub x} emissions. Utilisation of wood waste pyrolysis oil in diesel engines, however, involves a lot of challenges and problems to be solved. The low heating value requires a new injection system with high capacity. The corrosive characteristics of the fluid also underline the need for new injection equipment materials. Wood waste pyrolysis oil contains solid particles which can clog filters and cause abrasive wear. Wood waste pyrolysis oil has proven to have extremely bad ignition properties. The development of a reliable injection system which is able to cope with such a fuel involves a lot of optimisation tests, redesign and innovative solutions. Successful single-cylinder tests have already been performed and they have verified that diesel operation on wood pyrolysis oil is technically possible. (orig.)

  12. Oxygen isotope fractionation in phosphates: the role of dissolved complex anions in isotope exchange.

    Science.gov (United States)

    Zheng, Yong-Fei

    2016-01-01

    Oxygen isotope fractionation factors for phosphates were calculated by means of the increment method. The results suggest that Ag3PO4 and BiPO4 are enriched in (18)O relative to AgPO4, and the three phosphates are consistently depleted in (18)O relative to Ba3[PO4]2; fluorapatite and chlorapatite exhibit a similar behaviour of oxygen isotope fractionation with consistent enrichment of (18)O relative to hydroxyapatite. The valence, radii and coordination of metal cations play a quantitative role in dictating the (18)O/(16)O partitioning in these phosphates of different compositions. The calculated fractionation factors for the Ag3PO4-H2O system are in agreement with experimental determinations derived from enzyme-catalysed isotope exchange between dissolved inorganic phosphate and water at the longest reaction durations at low temperatures. This demonstrates that the precipitated Ag3PO4 has completely captured the oxygen isotope fractionation in the dissolved inorganic phosphate. The calculated fractionation factors for the F/Cl-apatite-water systems are in agreement with the enzyme-catalysed experimental fractionations for the dissolved phosphate-water system at the longest reaction durations but larger than fractionations derived from bacteria-facilitated exchange and inorganic precipitation experiments as well as natural observations. For the experimental calibrations of oxygen isotope fractionation involving the precipitation of dissolved phosphate species from aqueous solutions, the fractionation between precipitate and water is primarily dictated by the isotope equilibration between the dissolved complex anions and water prior to the precipitation. Therefore, the present results provide a quantitative means to interpret the temperature dependence of oxygen isotope fractionation in inorganic and biogenic phosphates.

  13. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2001-01-01

    Present and anticipated variation in jet propulsion fuels due to advanced engine compression ratios and airframe cooling requirements necessitate greater understanding of chemical phenomena associated...

  14. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2000-01-01

    Present and anticipated variation in jet propulsion fuels due to advanced engine compression ratios and airframe cooling requirements necessitate greater understanding of chemical phenomena associated...

  15. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater.

    Science.gov (United States)

    Liu, Xuewu; Byrne, Robert H; Adornato, Lori; Yates, Kimberly K; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-10-01

    Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  16. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

    Science.gov (United States)

    Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-01-01

    Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  17. Thin Robust Anion Exchange Membranes for Fuel Cell Applications

    Science.gov (United States)

    2014-01-01

    provide inexpensive compact power from a wider variety of fuels than is possible with a proton exchange membrane (PEM) fuel cell, has continued to...in aqueous solution. Interestingly though, while the proton transfer events in the anion exchange membrane are more frequent as would be ECS...release; distribution is unlimited. (Invited) Thin Robust Anion Exchange Membranes for Fuel Cell Applications The views, opinions and/or findings

  18. Selected methods for dissolved iron (II, III) and dissolved sulfide (-II) determinations in geothermal waters

    Science.gov (United States)

    Vivit, D.V.; Jenne, E.A.

    1985-01-01

    Dissolved sulfide (-II) and dissolved iron (II, III) were determined in geothermal well water samples collected at Cerro Prieto, Mexico. Most samples consisted of liquid and gas (two phases) at the instant of collection; and a subset of samples, referred to as ' flashed ' samples, consisted of pressurized steam samples which were allowed to condense. Sulfide was determined by sulfide specific ion electrode; Fe(II) and Fe(III) plus Fe(II) were determined spectrophotometrically. The precision and accuracy of the methods were evaluated for these high-silica waters with replicate analyses, spike recoveries, and an alternate method. Direct current (d.c.) argon plasma emission spectrometry was the alternate method used for Fe(III)-plus-Fe(II) analyses. Mean dissolved iron concentrations ranged from 20.2 to 834 micrograms/L (ug/L) as Fe(II) and 26.8 to 904 ug/L as Fe(III) plus Fe(II). Mean sulfide concentrations ranged from about 0.01 to 5.3 mg/L (S-II) Generally, higher S(-II) values and larger Fe(II)/Fe(III) ratios were found in the two-phase samples. These findings suggest that the ' flashed ' samples are at a less reduced state than the two-phase samples. (Author 's abstract)

  19. A novel aminated polymeric adsorbent for removing refractory dissolved organic matter from landfill leachate treatment plant

    Institute of Scientific and Technical Information of China (English)

    ZHANG Long; LI Aimin; WANG Jinnan; LU Yufei; ZHOU Youdong

    2009-01-01

    Refractory dissolved organic matter (DOM) from landfill leachate treatment plant was with high dissolved organic carbon (DOC) content.An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficient mesopore was synthesized, which exhibited high adsorption capacity to the DOM (raw water after coagulation).Resin NDA-8 performed better in the uptake of the DOM than resin DAX-8 and A100.Electrostatic attraction was considered as the decisive interaction between the adsorbent and adsorbate.Special attention was paid to the correlation between porous structure and adsorption capacity.The mesopore of NDA-8 played a crucial role during uptake of the DOM.In general, resin in chloride form performed a higher removal rate of DOC.According to the column adsorption test, total adsorption capacity of NDA-8 was calculated to 52.28 mg DOC/mL wet resin.0.2 mol/L sodium hydroxide solution could regenerate the adsorbent efficiently.

  20. Effect of biostimulation on biodegradation of dissolved organic carbon in biological filters

    Directory of Open Access Journals (Sweden)

    K. Tihomirova

    2012-07-01

    Full Text Available The addition of labile organic carbon (LOC to enhance the biodegradation rate of dissolved organic carbon (DOC in biological columns was studied. Acetate standard solution (NaAc and Luria Bertrani (LB medium were used as LOC as biostimulants in glass column system used for measurements of biodegradable dissolved organic carbon (BDOC. The addition of LOC related with the increase of total DOC in sample. The concentration of BDOC increased up to 7 and 5 times and was utilized after 24 min. contact time. The biodegradation rate constant was increased at least 26 times during adaptation-biostimulation period. There was a strong positive correlation between the biodegradation rate constant and the concentration of BDOC. Biostimulation period ranged from 24 to 53 h for NaAc biostimulant and from 20 to 168 h for LB. The study has shown that LOC could be used as stimulator to enhance the biodegradation rate of DOC during biofiltration.

  1. Effect of biostimulation on biodegradation of dissolved organic carbon in biological granular activated carbon filters

    Directory of Open Access Journals (Sweden)

    K. Tihomirova

    2012-03-01

    Full Text Available The addition of labile organic carbon (LOC to enhance the biodegradation rate of dissolved organic carbon (DOC in biological columns was studied. Acetate standard solution (NaAc and LB (Luria Bertrani medium were used as LOC as biostimulants in glass column system used for measurements of biodegradable dissolved organic carbon (BDOC. The addition of LOC related with the increase of total DOC in sample. The concentration of BDOC increased up to 7 and 5 times and was utilized after 24 min. contact time. The biodegradation rate constant was increased at least 8 times during adaptation-biostimulation period. There was a strong positive correlation between the biodegradation rate constant and the concentration of BDOC. Biostimulation period ranged from 24 to 53 h for NaAc biostimulant and from 20 to 168 h for LB. The study has shown that LOC could be used as stimulator to enhance the biodegradation rate of DOC during biofiltration.

  2. 77 FR 699 - Regulation of Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel...

    Science.gov (United States)

    2012-01-05

    ... January 5, 2012 Part V Environmental Protection Agency 40 CFR Part 80 Regulation of Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel Pathways Under the Renewable Fuel Standard... Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel Pathways Under...

  3. Materials for fuel cells

    Directory of Open Access Journals (Sweden)

    Sossina M Haile

    2003-03-01

    Full Text Available Because of their potential to reduce the environmental impact and geopolitical consequences of the use of fossil fuels, fuel cells have emerged as tantalizing alternatives to combustion engines. Like a combustion engine, a fuel cell uses some sort of chemical fuel as its energy source but, like a battery, the chemical energy is directly converted to electrical energy, without an often messy and relatively inefficient combustion step. In addition to high efficiency and low emissions, fuel cells are attractive for their modular and distributed nature, and zero noise pollution. They will also play an essential role in any future hydrogen fuel economy.

  4. Composite nuclear fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Dollard, W.J.; Ferrari, H.M.

    1982-04-27

    An open lattice elongated nuclear fuel assembly including small diameter fuel rods disposed in an array spaced a selected distance above an array of larger diameter fuel rods for use in a nuclear reactor having liquid coolant flowing in an upward direction. Plenums are preferably provided in the upper portion of the upper smaller diameter fuel rods and in the lower portion of the lower larger diameter fuel rods. Lattice grid structures provide lateral support for the fuel rods and preferably the lowest grid about the upper rods is directly and rigidly affixed to the highest grid about the lower rods.

  5. Materials Requirements for Advanced Energy Systems - New Fuels. Volume 3: Materials Research Needs in Advanced Energy Systems Using New Fuels

    Science.gov (United States)

    1974-07-01

    principal new fuel studied; hydrogen-derived fuels considere-d were ammonia, hydrazine, boranes, silanes, carbon monoxide, and methyl alcohol . The...NEEDED 𔄁O SbPPOR1 THE USE -F Item I No. Equipment Class Fuel Problem Ares. Type of Solution Materials Problema . Malerials E 1 . TURBINES (Con’t) 1.4.1 H...methyl alcohol . The materials implica- tionsof the use, transportation, and storage of oxygen (produced as a by-product in hydrogen generation) and of

  6. Complexation with dissolved organic matter and solubility control of heavy metals in a sandy soil.

    Science.gov (United States)

    Weng, Liping; Temminghoff, Erwin J M; Lofts, Stephen; Tipping, Edward; Van Riemsdijk, Willem H

    2002-11-15

    The complexation of heavy metals with dissolved organic matter (DOM) in the environment influences the solubility and mobility of these metals. In this paper, we measured the complexation of Cu, Cd, Zn, Ni, and Pb with DOM in the soil solution at pH 3.7-6.1 using a Donnan membrane technique. The results show that the DOM-complexed species is generally more significant for Cu and Pb than for Cd, Zn, and Ni. The ability of two advanced models for ion binding to humic substances, e.g., model VI and NICA-Donnan, in the simulation of metal binding to natural DOM was assessed by comparing the model predictions with the measurements. Using the default parameters of fulvic and humic acid, the predicted concentrations of free metal ions from the solution speciation calculation using the two models are mostly within 1 order of magnitude difference from the measured concentrations, except for Ni and Pb in a few samples. Furthermore, the solid-solution partitioning of the metals was simulated using a multisurface model, in which metal binding to soil organic matter, dissolved organic matter, clay, and iron hydroxides was accounted for using adsorption and cation exchange models (NICA-Donnan, Donnan, DDL, CD-MUSIC). The model estimation of the dissolved concentration of the metals is mostly within 1 order of magnitude difference from those measured except for Ni in some samples and Pb. The solubility of the metals depends mainly on the metal loading over soil sorbents, pH, and the concentration of inorganic ligands and DOM in the soil solution.

  7. Chemical Engineering Division fuel cycle programs. Quarterly progress report, October-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Steindler, M J; Ader, M; Barletta, R E

    1980-01-01

    In the program on pyrochemical and dry processing methods (PDPM) for nuclear fuel, tungsten crucibles were successfully spun for use in laboratory-scale experiments. Corrosion testing of refractory metals and alloys in PDPM environments was done. Ceramic substrates were successfully coated with tungsten. Solubility measurements were made to determine Cd/Mg alloy composition and temperature at which dissolved Th will precipitate. Experiments were started to study the reduction of high-fired ThO/sub 2/ with Ca in a molten metal-molten salt system. Work on the fused salt electrolysis of CaO was started. Equipment for determining phase diagrams for U-Cu-Mg system was set up. The reaction of UO/sub 2/ with molten equimolar NaNO/sub 3/-KNO/sub 3/ was studied as part of a project to identify chemically feasible nonaqueous fuel reprocessing methods. Work was continued on development of a flowsheet for reprocessing actinide oxides by extracting actinides into ammonium chloro-aluminate (and alternative salts) from a bismuth solution. Preparation of Th, U, and Pu nitrides after dissolution of spent fuel elements in molten tin is being studied. Leach rates of glass beads, pulverized beads, and beads encapsulated in a lead matrix with no protective envelope were studied. A method (employing no pressure or vacuum systems) of encapsulating various solid wastes in a lead metal matrix was developed and tested. A preliminary integration was made of earlier data on effects of impacts on metal-matrix waste forms.Leach migration experiments were compared with conventional infiltration experiments as methods of evaluating geologic formations as barriers to nuclide migration. The effect of the streaming potential on the rates of transport of radioactive I/sup -/ and Na/sup +/ through kaolinite columns was measured, as well as adsorption of iodide and iodate by several compounds; implications of the results upon the disposal of radioactive iodine are discussed.

  8. New insights in Microbial Fuel Cells: novel solid phase anolyte

    Science.gov (United States)

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-07-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  9. Biotic-Abiotic Nanoscale Interactions in Biological Fuel Cells

    Science.gov (United States)

    2014-03-28

    oneidensis MR-1 bacterial nanowires are lipid-based extensions of the outer- membrane and periplasmic electron transport proteins, Science Magazine...from a wide array of electron sources (fuels) and transfer them to electron acceptors (oxidants). Prokaryotes can use a wide variety of dissolved...well as direct transfer using multiheme cytochromes associated with the outer membrane (6). Recent reports have also suggested that extracellular

  10. Export of Dissolved Organic Matter, Nutrients and Carbon from Himalayan River System in Central Nepal

    Science.gov (United States)

    Bhatt, M. P.

    2014-12-01

    Chemical weathering is a vital ecosystem process and plays a central role in regulation of global carbon cycles. Weathering from Himalayan landscape supply high amount of major ions, nutrients and suspended sediments to the oceans. Surface water samples were collected from sixteen stations at different altitude along the Langtnag-Narayani Himalayan river system in central Nepal on a monthly basis for one year. This study aims to investigate spatiotemporal variations of dissolved organic matter, nutrients and carbonic species and to evaluate their controlling factors within the basin. The fluxes of these species appeared several fold higher at low elevation than at mid mountains and high elevation Himalaya sites. Seasonality appeared to exert major control on concentrations and fluxes of major solutes along the drainage network. The highest export rate of chemical species corresponded to the monsoon season, followed by the ones corresponding to post-monsoon and pre-monsoon seasons. Carbonate has major control on the flux of major solutes within the basin. The export rate of dissolved organic carbon and total dissolved nitrogen were about three and seventeen times higher respectively at the Narayani basin than its headwater at Langtang basin within the high Himalaya. Nitrate and phosphate export rates in the Narayani basin were 5.07 and 0.34 tons km-2 yr-1 respectively which is several fold higher than the rates in the high Himalaya probably due to input from agricultural activities. The export of dissolved inorganic carbon from the Narayani basin was 101.87 tons km-2 yr-1 of which bicarbonate appeared to be the dominant fraction (94.9%) followed by carbonic acid (4.7%) and carbonate (0.4%). Partial pressure of carbon dioxide (pCO2) resulted under-saturated in the high elevation Himalayan basin and supersaturated at the low elevation Narayani basin. The concentration of pCO2 is considered to be an important factor for regulating weathering rates of any landscape.

  11. Nonproliferation and safeguards aspects of the DUPIC fuel cycle concept

    Energy Technology Data Exchange (ETDEWEB)

    Persiani, P. K. [Argonne National Lab., IL (United States)

    1997-07-01

    The purpose of the study is to comment on the proliferation characteristic profiles of some of the proposed fuel cycle alternatives to help ensure that nonproliferation concerns are introduced into the early stages of a fuel cycle concept development program, and to perhaps aid in the more effective implementation of the international nonproliferation regime initiative and safeguards systems. Alternative recycle concepts proposed by several countries involve the recycle of spent fuel without the separation of plutonium from uranium and fission products. The concepts are alternatives to either the direct long-term storage deposition of or the purex reprocessing of the spent fuels. The alternate fuel cycle concepts reviewed include: the dry-recycle processes such as the direct use of reconfigured PWR spent fuel assemblies into CANDU reactors(DUPIC); low-decontamination, single-cycle co-extraction of fast reactor fuels in a wet-purex type of reprocessing; and on a limited scale the thorium-uranium fuel cycle. The nonproliferation advantages usually associated with the above non-separation processes are: the highly radioactive spent fuel presents a barrier to the physical diversion of the nuclear material; avoid the need to dissolve and chemically separate the plutonium from the uranium and fission products; and that the spent fuel isotopic quality of the plutonium vector is further degraded. Although the radiation levels and the need for reprocessing may be perceived as barriers to the terrorist or the subnational level of safeguards, the international level of nonproliferation concerns is addressed primarily by material accountancy and verification activities. On the international level of nonproliferation concerns, the non-separation fuel cycle concepts involved have to be evaluated on the bases of the impact the processes may have on nuclear materials accountancy. (author).

  12. To study the effect of solvent, viscosity, and temperature on the mouth-dissolving film of Withania somnifera Linn

    Directory of Open Access Journals (Sweden)

    Anwar Daud

    2012-01-01

    Full Text Available An oral-dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules, and so on. Withania somnifera has been used to promote health and longevity by augmenting defenses against disease, arresting the aging process, revitalizing the body in debilitated conditions, and thus creating a sense of well-being. Commercially, it is available either in powder or liquid dosage forms that do not offer patient compliance. In the present study, an attempt has been made to formulate W. somnifera into thin oral films. An attempt was also made to study factors like the effect of the type of solvent used for casting of the film, effect of drying temperature, and viscosity of the solution on the mouth-dissolving film of W. somnifera Linn. The mouth-dissolving films were prepared by the solvent-casting method. Prepared films were evaluated for film-forming capacity, appearance of film, tack test, thickness, in vitro disintegration time, folding endurance, tensile strength, and percentage elongation. This study illustrated that selected process variables have an influence on the physicomechanical properties of the mouth-dissolving film of W. somnifera Linn. Water was found to be an excellent solvent for casting when hydroxypropylmethylcellulose was used as a film former. When mouth-dissolving film of W. somnifera Linn was dried at lower temperatures, it showed optimum physicomechanical performances. Viscosity of the solution plays an important role in physicomechanical properties of the film; as the viscosity of solution increases, there is an increase in folding endurance, tensile strength, and percentage elongation.

  13. Increasing Fuel Efficiency of Direct Methanol Fuel Cell Systems with Feedforward Control of the Operating Concentration

    Directory of Open Access Journals (Sweden)

    Youngseung Na

    2015-09-01

    Full Text Available Most of the R&D on fuel cells for portable applications concentrates on increasing efficiencies and energy densities to compete with other energy storage devices, especially batteries. To improve the efficiency of direct methanol fuel cell (DMFC systems, several modifications to system layouts and operating strategies are considered in this paper, rather than modifications to the fuel cell itself. Two modified DMFC systems are presented, one with an additional inline mixer and a further modification of it with a separate tank to recover condensed water. The set point for methanol concentration control in the solution is determined by fuel efficiency and varies with the current and other process variables. Feedforward concentration control enables variable concentration for dynamic loads. Simulation results were validated experimentally with fuel cell systems.

  14. Hybrid fusion reactor for production of nuclear fuel with minimum radioactive contamination of the fuel cycle

    Science.gov (United States)

    Velikhov, E. P.; Kovalchuk, M. V.; Azizov, E. A.; Ignatiev, V. V.; Subbotin, S. A.; Tsibulskiy, V. F.

    2015-12-01

    The paper presents the results of the system research on the coordinated development of nuclear and fusion power engineering in the current century. Considering the increasing problems of resource procurement, including limited natural uranium resources, it seems reasonable to use fusion reactors as high-power neutron sources for production of nuclear fuel in a blanket. It is shown that the share of fusion sources in this structural configuration of the energy system can be relatively small. A fundamentally important aspect of this solution to the problem of closure of the fuel cycle is that recycling of highly active spent fuel can be abandoned. Radioactivity released during the recycling of the spent fuel from the hybrid reactor blanket is at least two orders of magnitude lower than during the production of the same number of fissile isotopes after the recycling of the spent fuel from a fast reactor.

  15. DUPIC fuel compatibility assessment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok; Rho, G. H.; Park, J. W. [and others

    2000-03-01

    The purpose of this study is to assess the compatibility of DUPIC(Direct Use of Spent PWR Fuel in CANDU Reactors) fuel with the current CANDU 6 reactor, which is one of the technology being developed to utilize the spent PWR fuel in CANDU reactors. The phase 1 study of this project includes the feasibility analysis on applicability of the current core design method, the feasibility analysis on operation of the DUPIC fuel core, the compatibility analysis on individual reactor system, the sensitivity analysis on the fuel composition, and the economic analysis on DUPIC fuel cycle. The results of the validation calculations have confirmed that the current core analysis system is acceptable for the feasibility study of the DUPIC fuel compatibility analysis. The results of core simulations have shown that both natural uranium and DUPIC fuel cores are almost the same from the viewpoint of the operational performance. For individual reactor system including reactively devices, the functional requirements of each system are satisfied in general. However, because of the pronounced power flattening in the DUPIC core, the radiation damage on the critical components increases, which should be investigated more in the future. The DUPIC fuel composition heterogeneity dose not to impose any serious effect on the reactor operation if the fuel composition is adjusted. The economics analysis has been performed through conceptual design studies on the DUPIC fuel fabrication, fuel handling in a plant, and spent fuel disposal, which has shown that the DUPIC fuel cycle is comparable to the once-trough fuel cycle considering uncertainties associated with unit costs of the fuel cycle components. The results of Phase 1 study have shown that it is feasible to use the DUPIC fuel in CANDU reactors without major changes in hardware. However further studies are required to confirm the safety of the reactor under accident condition.

  16. Zonal distribution of dissolved aluminium in the Mediterranean Sea

    NARCIS (Netherlands)

    Rolison, J. M.; Middag, R.; Stirling, C. H.; Rijkenberg, M. J. A.; de Baar, H. J. W.

    2015-01-01

    Dissolved aluminium (Al) is an important tracer of atmospheric dust input to the oceans. The GEOTRACES expedition to the highly dust impacted Mediterranean Sea afforded the opportunity to study the distribution of dissolved Al in the Mediterranean Sea in detail. Interestingly, the elevated concentra

  17. The dependence on temperature and salinity of dissolved

    NARCIS (Netherlands)

    Bakker, Dorothee C.E.; Baar, Hein J.W. de; Jong, Edwin de

    1999-01-01

    Recurring latitudinal patterns of the dissolved inorganic carbon (DIC) content and the fugacity of CO2 (fCO2) were observed in East Atlantic surface waters with strong gradients at hydrographic fronts. The dissolved inorganic carbon chemistry clearly displayed the effects of oceanic circulation and

  18. High export of dissolved silica from the Greenland Ice Sheet

    NARCIS (Netherlands)

    Meire, L.; Meire, P.; Struyf, E.; Krawczyk, D.W.; Arendt, K.E.; Yde, J.C.; Juul-Pedersen, T.; Hopwood, M. J.; Rysgaard, S.; Meysman, F.J.R.

    2016-01-01

    Silica is an essential element for marine life and plays a key role in the biogeochemistry ofthe ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported tocoastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial area

  19. Explorations of soil microbial processes driven by dissolved organic carbon

    NARCIS (Netherlands)

    Straathof, A.L.

    2015-01-01

    Explorations of soil microbial processes driven by dissolved organic carbon Angela L. Straathof June 17, 2015, Wageningen UR ISBN 978-94-6257-327-7 Abstract Dissolved organic carbon (DOC) is a complex, heterogeneous mixture of C compounds which, as

  20. High export of dissolved silica from the Greenland Ice Sheet

    NARCIS (Netherlands)

    Meire, L.; Meire, P.; Struyf, E.; Krawczyk, D.W.; Arendt, K.E.; Yde, J.C.; Juul-Pedersen, T.; Hopwood, M.J.; Rysgaard, S.; Meysman, F.J.R.

    2016-01-01

    Silica is an essential element for marine life and plays a key role in the biogeochemistry of the ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported to coastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial

  1. Simulation of alpha dose for predicting radiolytic species at the surface of spent nuclear fuel pellets

    OpenAIRE

    Becker Frank; Kienzler Bernhard

    2014-01-01

    In many countries, spent nuclear fuel is considered as a waste form to be disposed of in underground disposal. Under deep host rock conditions, a reducing environment prevails. In the case of water contact, long-term radionuclide release from the fuel depends on dissolution processes of the UO2 matrix. The dissolution rate of irradiated UO2 is controlled by oxidizing processes facilitated by dissolved species formed by alpharadiolysis of water in contact with spent nuc...

  2. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes....... With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid...

  3. Recycling as an option of used nuclear fuel management strategy

    Energy Technology Data Exchange (ETDEWEB)

    Zagar, Tomaz, E-mail: tomaz.zagar@gen-energija.s [GEN energija, d.o.o., Cesta 4. julija 42, 8270 Krsko (Slovenia); Institute Jozef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); Bursic, Ales; Spiler, Joze [GEN energija, d.o.o., Cesta 4. julija 42, 8270 Krsko (Slovenia); Kim, Dana; Chiguer, Mustapha; David, Gilles; Gillet, Philippe [AREVA, 33 rue La Fayette, 75009 Paris (France)

    2011-04-15

    The paper presents recycling as an option of used nuclear fuel management strategy with specific focus on the Slovenia. GEN energija is an independent supplier of integral and competitive electricity for Slovenia. In response to growing energy needs, GEN has conducted several feasibility and installation studies of a new nuclear power plant in Slovenia. With sustainable development, the environment, and public acceptance in mind, GEN conducted a study with AREVA concerning the options for the management of its' new plant's used nuclear fuel. After a brief reminder of global political and economic context, solutions for used nuclear fuel management using current technologies are presented in the study as well as an economic assessment of a closed nuclear fuel cycle. The paper evaluates and proposes practical solutions for mid-term issues on used nuclear fuel management strategies. Different scenarios for used nuclear fuel management are presented, where used nuclear fuel recycling (as MOX, for mixed oxide fuel, and ERU, for enriched reprocessed uranium) are considered. The study concludes that closing the nuclear fuel cycle will allow Slovenia to have a supplementary fuel supply for its new reactor via recycling, while reducing the radiotoxicity, thermal output, and volume of its wastes for final disposal, reducing uncertainties, gaining public acceptance, and allowing time for capitalization on investments for final disposal.

  4. Can redox sensitive radionuclides be immobilized on the surface of spent nuclear fuel? - A model study on the reduction of Se(IV) aq on Pd-doped UO 2 under H 2 atmosphere

    Science.gov (United States)

    Puranen, Anders; Trummer, Martin; Jonsson, Mats

    2009-08-01

    Spent nuclear fuel contains noble metal particles composed of fission products (Pd, Mo, Ru, Tc, Rh and Te, often referred to as ɛ-particles). Studies have shown that these particles play a major role in catalyzing oxidative dissolution as well as H 2 reduction of the oxidized UO 2 fuel matrix, depending on the conditions. Thus it is possible that these particles also could have a major impact on the state of other redox sensitive radionuclides (such as the long lived fission product 79Se) present in spent nuclear fuel. In this study, Pd-doped UO 2 pellets are used to simulate noble metal particles inclusions in spent nuclear fuel and the effect on dissolved selenium in the form of selenite (250 μM selenite) in simulated ground water solution (10 mM NaCl, 10 mM NaHCO 3) at 1 and 10 bar hydrogen pressure. The selenite was found to be reduced to elemental Se, forming colloidal particles. At hydrogen pressures of 10 bar, the rate of selenite reduction was found to be linearly correlated to the fraction of Pd in the UO 2 pellets. No selenium was detected on the surface of the pellets. For the lowest Pd loading (0.1% Pd) the selenite reduction does not appear to proceed to completion indicating that the surface becomes less active.

  5. Cleanup of a jet fuel spill

    Science.gov (United States)

    Fesko, Steve

    1996-11-01

    Eaton operates a corporate aircraft hanger facility in Battle Creek, Michigan. Tests showed that two underground storage tanks leaked. Investigation confirmed this release discharged several hundred gallons of Jet A kerosene into the soil and groundwater. The oil moved downward approximately 30 feet and spread laterally onto the water table. Test results showed kerosene in the adsorbed, free and dissolved states. Eaton researched and investigated three clean-up options. They included pump and treat, dig and haul and bioremediation. Jet fuel is composed of readily biodegradable hydrocarbon chains. This fact coupled with the depth to groundwater and geologic setting made bioremediation the low cost and most effective alternative. A recovery well was installed at the leading edge of the dissolved contamination. A pump moved water from this well into a nutrient addition system. Nutrients added included nitrogen, phosphorous and potassium. Additionally, air was sparged into the water. The water was discharged into an infiltration gallery installed when the underground storage tanks were removed. Water circulated between the pump and the infiltration basin in a closed loop fashion. This oxygenated, nutrient rich water actively and aggressively treated the soils between the bottom of the gallery and the top of the groundwater and the groundwater. The system began operating in August of 1993 and reduced jet fuel to below detection levels. In August of 1995 The State of Michigan issued a clean closure declaration to the site.

  6. VASOACTIVE COMPONENTS OF DIALYSIS SOLUTION

    Science.gov (United States)

    Zakaria, El Rasheid; Patel, Anuj A.; Li, Na; Matheson, Paul J.; Garrison, Richard N.

    2008-01-01

    Background Conventional peritoneal dialysis (PD) solutions elicit vasodilation, which is implicated in the variable rate of solute transport during the dwell. The components causing such vasoactivity are still controversial. This study was conducted to define the vasoactive components of conventional and new PD solutions. Methods Three visceral peritoneal microvascular levels were visualized by intravital video microscopy of the terminal ileum of anesthetized rats. Anesthesia-free decerebrate conscious rats served as control. Microvascular diameter and blood flow by Doppler measurements were conducted after topical peritoneal exposure to 4 clinical PD solutions and 6 prepared solutions designed to isolate potential vasoactive components of the PD solution. Results All clinically available PD solutions produced a rapid and generalized vasodilation at all intestinal microvascular levels, regardless of the osmotic solute. The pattern and magnitude of this dilation was not affected by anesthesia but was determined by arteriolar size, the osmotic solute, and the solution’s buffer anion system. The greatest dilation occurred in the small precapillary arterioles and was elicited by conventional PD solution and heat re-sterilized solution containing low glucose degradation products (GDPs). Hypertonic mannitol solutions produced a dilation that was approximately 50% less than the dilation obtained with glucose solutions with identical osmolarity and buffer. Increasing a solution’s osmolarity did not produce a parallel increase in the magnitude of dilation, suggesting a nonlinear relationship between the two variables. Lactate dissolved in an isotonic solution was completely non-vasoactive unless the solution’s H+ concentration was increased. At low pH, isotonic lactate produced a rapid but transient vasodilation. This vascular reactivity was similar in magnitude and pattern to that obtained with the isotonic 7.5% icodextrin solution (Extraneal; Baxter Healthcare

  7. Size-fractionated production and bioavailability of dissolved organic matter

    DEFF Research Database (Denmark)

    Knudsen-Leerbeck, Helle; Bronk, Deborah A.; Markager, Stiig

    Production and bioavailability of dissolved organic matter was quantified on a time scale of two days from size fractions ranging from bacteria to zooplankton in the York River, Virginia. The goal was to find the main contributor to DOM. Batch incubation experiments were labeled with N15-ammonium...... was mainly in the phytoplankton size fraction, which on average contributed 62 % of total particulate nitrogen and 61 % of total particulate carbon. Up to 5 ± 0.4 μmol dissolved organic nitrogen L-1 and 33 ± 6.2 μmol dissolved organic carbon L-1 was produced during the incubation. Bioavailability...... of phytoplankton produced dissolved organic carbon was 12 ± 1 % and higher than in the presence of bacteria, microzooplankton, or copepods (7 ± 3 %). The pattern for bioavailability of dissolved organic nitrogen was less clear and ranged from 4 – 7 %. This study revealed that phytoplankton was the main contributor...

  8. Optimizing dissolved air flotation design system

    Directory of Open Access Journals (Sweden)

    L.A. Féris

    2000-12-01

    Full Text Available Dissolved Air (Pressure Flotation-DAF, is a well-established separation process that employs micro-bubbles as a carrier phase. This work shows results concerning bubble generation at low working pressures in modified DAF-units to improve the collection of fragile coagula by bubbles. DAF of Fe (OH3 (as model was studied as a function of saturation pressure in the absence and presence of surfactants in the saturator. DAF was possible at 2 atm by lowering the air/water surface tension. This fact, which leads to substantial energy savings, was explained in terms of decreasing the "minimum" energy required for bubble nucleation and cavity in the nozzle. More, bubbles-fragile coagula attachment was improved by dividing the recycling water into two: 1 the inclined inlet to the cell (traditional and 2 inside the separation tank through a water flow inlet situated below the floating bed using a "mushroom" type diffuser. Because of the reduction observed in the degree of turbulence in the conventional collection zone, DAF performance improved yielding high precipitate recoveries.

  9. Composition of dissolved organic matter in groundwater

    Science.gov (United States)

    Longnecker, Krista; Kujawinski, Elizabeth B.

    2011-05-01

    Groundwater constitutes a globally important source of freshwater for drinking water and other agricultural and industrial purposes, and is a prominent source of freshwater flowing into the coastal ocean. Therefore, understanding the chemical components of groundwater is relevant to both coastal and inland communities. We used electrospray ionization coupled with Fourier-transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to examine dissolved organic compounds in groundwater prior to and after passage through a sediment-filled column containing microorganisms. The data revealed that an unexpectedly high proportion of organic compounds contained nitrogen and sulfur, possibly due to transport of surface waters from septic systems and rain events. We matched 292 chemical features, based on measured mass:charge ( m/z) values, to compounds stored in the Kyoto Encyclopedia of Genes and Genomes (KEGG). A subset of these compounds (88) had only one structural isomer in KEGG, thus supporting tentative identification. Most identified elemental formulas were linked with metabolic pathways that produce polyketides or with secondary metabolites produced by plants. The presence of polyketides in groundwater is notable because of their anti-bacterial and anti-cancer properties. However, their relative abundance must be quantified with appropriate analyses to assess any implications for public health.

  10. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  11. Aviation Fueling: A Cleaner, Greener Approach

    Science.gov (United States)

    Hendricks, Robert C.; Bushnell, Dennis M.; Shouse, Dale T.

    2010-01-01

    Projected growth of aviation depends on fueling where specific needs must be met. Safety is paramount, and along with political, social, environmental and legacy transport systems requirements, alternate aviation fueling becomes an opportunity of enormous proportions. Biofuels sourced from halophytes, algae, cyanobacteria, and weeds using wastelands, waste water, and seawater have the capacity to be drop-in fuel replacements for petroleum fuels. Biojet fuels from such sources solves the aviation CO2 emissions issue and do not compete with food or freshwater needs. They are not detrimental to the social or environmental fabric and use the existing fuels infrastructure. Cost and sustainable supply remains the major impediments to alternate fuels. Halophytes are the near-term solution to biomass/biofuels capacity at reasonable costs; they simply involve more farming, at usual farming costs. Biofuels represent a win-win approach, proffering as they do at least the ones we are studying massive capacity, climate neutral-to-some sequestration, and ultimately, reasonable costs.

  12. Aviation Fueling: A Cleaner, Greener Approach

    Directory of Open Access Journals (Sweden)

    Robert C. Hendricks

    2011-01-01

    Full Text Available Projected growth of aviation depends on fueling where specific needs must be met. Safety is paramount, and along with political, social, environmental, and legacy transport systems requirements, alternate aviation fueling becomes an opportunity of enormous proportions. Biofuels—sourced from halophytes, algae, cyanobacteria, and “weeds” using wastelands, waste water, and seawater—have the capacity to be drop-in fuel replacements for petroleum fuels. Biojet fuels from such sources solve the aviation CO2 emissions issue and do not compete with food or freshwater needs. They are not detrimental to the social or environmental fabric and use the existing fuels infrastructure. Cost and sustainable supply remain the major impediments to alternate fuels. Halophytes are the near-term solution to biomass/biofuels capacity at reasonable costs; they simply involve more farming, at usual farming costs. Biofuels represent a win-win approach, proffering as they do—at least the ones we are studying—massive capacity, climate neutral-to-some sequestration, and ultimately, reasonable costs.

  13. Development and optimization of microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Davila, D.; Vigues, N.; Sanchez, O.; Garrido, L.; Tomas, N.; Mas, J. [Univ. Autonoma de Barcelona, Barcelona (Spain). Dept. de Genetica y Microbiologia; Esquivel, J.P.; Sabate, N.; Del Campo, F.J.; Munoz, F.J. [Inst. de Microelectronica de Barcelona-CNM (CSIC), Barcelona (Spain)

    2008-04-15

    While global energy demand increases daily, fossil fuel sources are being depleted at an unsustainable pace. Fuel cells represent a solution as they are more efficient than other energy sources. A microbial fuel cell is an electrochemical device capable of continuously converting chemical energy into electrical energy for as long as adequate fuel and oxidant are available. A microbial fuel cell (MFC) adds the benefit of converting chemical energy from organic compounds, such as simple carbohydrates or organic waste matter, into electricity by using bacteria as biocatalysts. This article described the effect of several parameters that affect the operation of a microbial fuel cell (MFC). The study is based on a methodology utilized in previous studies which employed escherichia coli as biocatalyst and neutral red as the electron mediator in a mediated electron transfer (MET) microbial fuel cell. The study analysed the influence of the bacterial concentration, the effective area of electrode and the volume of the cell. It was concluded that there is a proportional energy production to the bacterial concentration present in the anode compartment. It was demonstrated that an increase in the volume of the cell negatively affects the power produced by the cells. 8 refs., 1 tab., 5 figs.

  14. Direct hydrocarbon fuel cells

    Science.gov (United States)

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  15. Navy Fuel Specification Standardization

    Science.gov (United States)

    1992-04-01

    surfaced periodically to convert further to a single-fuel operation, i.e., one fuel for both aircraft and ship propulsion /power systems. This study...lead to the development of a single distillate fuel for ship propulsion , resulting eventually in the MIL-F-16884 Naval Distillate Fuel (NDF) used today...for both aircraft and ship propulsion /power systems. This report summarizes a study to consider this problem in light of current systems and

  16. 混合动力汽车燃油箱压力问题解决方案%Solution to the Pressure Problem of Hybrid Electric Vehicle Fuel Tank

    Institute of Scientific and Technical Information of China (English)

    孙涛

    2015-01-01

    针对混合动力汽车在纯电动行驶模式时燃油箱压力不断升高的问题,在一些高端车型上最近采用了一种叫做压力油箱电子控制系统的新技术。本文介绍了压力油箱的结构,并深入解析了压力油箱电子控制系统的电子控制原理。%〔Abstract〕 For the rising pressure of hybrid electric vehicle in the pure electric drive mode fuel tank, a new technology called pressure tank of electronic control system is adopted in some high-end models re-cently. This article introduced the pressure tank structure, and further analyzes the pressure tank electronic control principle of electronic control system.

  17. Semi-fuel cell studies for powering underwater devices: integrated design for maximized net power output

    Science.gov (United States)

    Cardenas-Valencia, Andres M.; Short, R. Timothy; Adornato, Lori; Langebrake, Larry

    2010-04-01

    Use of sensor systems in water bodies has applications that range from environmental and oceanographic research to port and homeland security. Power sources are often the limiting component for further reduction of sensor system size and weight. We present recent investigations of metal-anode water-activated galvanic cells, specifically water-activated Alcells using inorganic alkali peroxides and solid organic oxidizers (heterocyclic halamines), in a semi-fuel cell configuration (i.e., with cathode species generated in situ and flow-through cells). The oxidizers utilized are inexpensive solid materials that are generally (1) safer to handle than liquid solutions or gases, (2) have inherently higher current and energy capacity (as they are not dissolved), and, (3) if appropriately packaged, will not degrade over time. The specific energy (S.E.) of Al-alkali peroxide was found to be 230 Wh/kg (460 Wh/kg, considering only active materials) in a seven-gram cell. Interestingly, when the cell size was increased (making more area of the catalytic cathode electrode available), the results from a single addition of water in an Al-organic oxidizer cell (weighing ~18 grams) showed an S.E. of about 200 Wh/kg. This scalability characteristic suggests that values in excess of 400 Wh/kg could be obtained in a semi-fuel-cell-like system. In this paper, we also present design considerations that take into account the energy requirements of the pumping devices and show that the proposed oxidizers, and the possible control of the chemical equilibrium of these cathodes in solution, may help reduce this power requirement and hence enhance the overall energetic balance.

  18. Modeling: driving fuel cells

    Directory of Open Access Journals (Sweden)

    Michael Francis

    2002-05-01

    Fuel cells were invented in 1839 by Sir William Grove, a Welsh judge and gentleman scientist, as a result of his experiments on the electrolysis of water. To put it simply, fuel cells are electrochemical devices that take hydrogen gas from fuel, combine it with oxygen from the air, and generate electricity and heat, with water as the only by-product.

  19. Alternate Fuels Combustion Research

    Science.gov (United States)

    1983-10-01

    properties of the other fuels are varied systematically beyond the specification limits imposed on the reference fuels, principally in the direction of...lower hydrogen content- Comparison of fuel nozzles, Figurae ,6.32. shows stronger dependence bet- ween oeiseslona and hydrogen content for airblast and

  20. Vented nuclear fuel element

    Science.gov (United States)

    Grossman, Leonard N.; Kaznoff, Alexis I.

    1979-01-01

    A nuclear fuel cell for use in a thermionic nuclear reactor in which a small conduit extends from the outside surface of the emitter to the center of the fuel mass of the emitter body to permit escape of volatile and gaseous fission products collected in the center thereof by virtue of molecular migration of the gases to the hotter region of the fuel.

  1. Alternative Fuels Data Center

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-06-01

    Fact sheet describes the Alternative Fuels Data Center, which provides information, data, and tools to help fleets and other transportation decision makers find ways to reduce petroleum consumption through the use of alternative and renewable fuels, advanced vehicles, and other fuel-saving measures.

  2. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...

  3. Palm oil and derivatives: fuels or potential fuels?

    Directory of Open Access Journals (Sweden)

    Pioch Daniel

    2005-03-01

    Full Text Available Scientific and technical information including field trials about uses of palm oil as fuel has been available for more than half a century now. Several ways were investigated, from the simple mixture with petroleum Diesel fuel, to more sophisticated solutions. The quality of vegetable oils in natura as fuel is difficult to assess because of interferences between properties of the triacylglycerols – the main components – and those of the many minor components, their content varying significantly from sample to sample. A methodology set up at Cirad allowed to investigate separately natural triacylglycerols alone and the effect of minor components. In addition to these laboratory experiments, engine test at bench and field trials performed in palm oil producing countries, show that this oil is among the best oils as fuel; palm kernel oil whose chemical and physical properties are very close to those of the best of the series investigated, namely copra oil, should display also very interesting properties as Diesel biofuel. Both oils do require external adaptation of the engine when using an indirect injection type engine but even heavier adaptations for a direct injection model. Thus for use as Diesel fuel palm and palm kernel oils are suitable for captive fleets or for engine gensets, to balance the adaptation cost by a scale-up effect either on the number of identical engines or on the nominal vegetable oil consumption per set. Direct use of palm et palm kernel oils fits very well with technical and economical conditions encountered in remote areas. It is also possible to mix palm oil to Diesel fuel either as simple blend or as micro-emulsion. Out of the direct use, palm oil methyl or ethyl ester, often referred to as biodiesel, displays properties similar to those of petroleum Diesel fuel. This technical solution which is suitable to feed all kinds of standard compression ignited engines requires a chemical plant for carrying out the

  4. Preparation and emission characteristics of ethanol-diesel fuel blends

    Institute of Scientific and Technical Information of China (English)

    ZHANG Run-duo; HE Hong; SHI Xiao-yan; ZHANG Chang-bin; HE Bang-quan; WANG Jian-xin

    2004-01-01

    The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.

  5. In-situ measurement of the dissolved S2- in seafloor diffuse flow system: sensor preparation and calibration

    Institute of Scientific and Technical Information of China (English)

    Ying YE; Xia HUANG; Yi-wen PAN; Chen-hua HAN; Wei ZHAO

    2008-01-01

    The preparation approach and calibration result of an improved type of ion selective electrode (ISE), which is used to measure the total dissolved S2-, are introduced in this paper. The improved Ag/Ag2S electrode uses silver wire as the substrate, which is surrounded by electric polymer containing superfine silver powder. After the stabilization of the epoxy-resin, Ag2ES layer was formed by chemical reaction with 0.2 mol/L (NH4)2S solution for 5 min. With Ag/AgCl as reference electrode, the Ag/Ag2S electrode can be used to measure dissolved S2-. The correlation between the measured potentials and the logarithm of dissolved S2- is found to be linear, within range of the concentration of dissolved S2- from 10-2~10-7 mol/L. The slope of the regression line between measured potential and logarithm of dissolved S2- is about -27.7, which agrees well with the theoretical Nernst value -29.6. Furthermore, the performance of the improved Ag/Ag2S electrode, such as the response time, sensitivity and stability, greatly outweighs the conventional Ag/Ag2S electrode.

  6. LWRS Fuels Pathway: Engineering Design and Fuels Pathway Initial Testing of the Hot Water Corrosion System

    Energy Technology Data Exchange (ETDEWEB)

    Dr. John Garnier; Dr. Kevin McHugh

    2012-09-01

    The Advanced LWR Nuclear Fuel Development R&D pathway performs strategic research focused on cladding designs leading to improved reactor core economics and safety margins. The research performed is to demonstrate the nuclear fuel technology advancements while satisfying safety and regulatory limits. These goals are met through rigorous testing and analysis. The nuclear fuel technology developed will assist in moving existing nuclear fuel technology to an improved level that would not be practical by industry acting independently. Strategic mission goals are to improve the scientific knowledge basis for understanding and predicting fundamental nuclear fuel and cladding performance in nuclear power plants, and to apply this information in the development of high-performance, high burn-up fuels. These will result in improved safety, cladding, integrity, and nuclear fuel cycle economics. To achieve these goals various methods for non-irradiated characterization testing of advanced cladding systems are needed. One such new test system is the Hot Water Corrosion System (HWCS) designed to develop new data for cladding performance assessment and material behavior under simulated off-normal reactor conditions. The HWCS is capable of exposing prototype rodlets to heated, high velocity water at elevated pressure for long periods of time (days, weeks, months). Water chemistry (dissolved oxygen, conductivity and pH) is continuously monitored. In addition, internal rodlet heaters inserted into cladding tubes are used to evaluate repeated thermal stressing and heat transfer characteristics of the prototype rodlets. In summary, the HWCS provides rapid ex-reactor evaluation of cladding designs in normal (flowing hot water) and off-normal (induced cladding stress), enabling engineering and manufacturing improvements to cladding designs before initiation of the more expensive and time consuming in-reactor irradiation testing.

  7. Analysis of the influence of fuel on NiFe{sub 2}O{sub 4} nanocrystalline obtained by solution combustion synthesis; Influencia do tipo de combustivel sobre NiFe{sub 2}O{sub 4} nanocristalina obtida a partir da sintese por combustao em solucao

    Energy Technology Data Exchange (ETDEWEB)

    Dalt, S. Da; Bergmann, C.P., E-mail: silvana.da.dalt@ufrgs.b [Universidade Federal do Rio Grande do Sul (LACER/UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia. Lab. de Materiais Ceramicos

    2009-07-01

    This paper investigates the effect of different fuels used on a structural properties stoichiometric composition of NiFe{sub 2}O{sub 4} obtained from the combustion synthesis. Precursor solutions were prepared from iron nitrate nonahydrate and nickel nitrate hexahydrate, and complexing agents as maleic anhydride, oxalic acid and sucrose. The samples were characterized by X-ray diffraction to evaluate the presents phases, and crystallite size from single-line method, specific surface area (BET) and scanning electron microscopy (SEM) for morphological analysis of powders. The results indicate that NiFe{sub 2}O{sub 4} can be obtained after heat treatment at 800 deg C with particle size of approximately 60nm. (author)

  8. PEM fuel cell catalyst degradation mechanism and mathematical modeling

    Science.gov (United States)

    Bi, Wu

    The durability of carbon-supported platinum oxygen reduction electrocatalysts is one of the limiting factors for their commercial applications in PEM fuel cell cathodes. In this work, we applied both experimental and numerical tools to study Pt/C catalyst degradation mechanisms. An accelerated catalyst degradation protocol through cycling the cathode potential in a square-wave profile was applied to study cell performances, Pt/C catalyst ORR activity, and active surface area losses. Post-mortem analyses of cathode Pt particle size were conducted by X-ray diffraction. Changes of platinum distributions in CCMs were studied by SEM/EDS analyses with surface coated Au as the reference element. The mechanisms of platinum deposition in membrane were investigated. It was confirmed by the SEM/EDS Pt distribution analyses that the deposited Pt atoms originated from the cathode. It was hypothesized that dissolved Pt ions from the cathode diffused into the membrane and were reduced by the permeated hydrogen from the anode. These deposited Pt atoms catalyzed the combustion of permeated oxygen and hydrogen. Pt band was predicted and experimentally confirmed at the location where the permeated hydrogen and oxygen completely reacted with each other. An active research thrust for PEM fuel cells is the development of membranes for high temperature (above 80°C) and low humidity operations. However a large tradeoff the benefits running fuel cell at relatively high temperatures was observed due to the accelerated cathode degradation processes. And at low humidity conditions, the cathode degradation rate decreased due to the slow transport of soluble platinum ions in possible narrowed/limited water (or ionic) channel networks in polymer electrolytes. From the Pt dissolution experiments in 0.5 M HClO4 solution, large positive effects of holding potentials on dissolution rates and soluble Pt concentrations were observed. Without an external holding potential, Pt dissolution rate was

  9. The effect of fuel chemistry on UO2 dissolution

    Science.gov (United States)

    Casella, Amanda; Hanson, Brady; Miller, William

    2016-08-01

    The dissolution rate of both unirradiated UO2 and used nuclear fuel has been studied by numerous countries as part of the performance assessment of proposed geologic repositories. In the scenario of waste package failure and groundwater contact with the fuel, the effects of variables such as temperature, dissolved oxygen, and water and fuel chemistry on the dissolution rates of the fuel are necessary to provide a quantitative estimate of the potential release over geologic time frames. The primary objective of this research was to determine the influence these parameters, with primary focus on the fuel chemistry, have on the dissolution rate of unirradiated UO2 under oxidizing repository conditions and compare them to the rates predicted by current dissolution models. Both unirradiated UO2 and UO2 doped with varying concentrations of Gd2O3, to simulate used fuel composition after long time periods when radiolysis has minor contributions to dissolution, were examined. In general, a rise in temperature increased the dissolution rate of UO2 and had a larger effect on pure UO2 than on those doped with Gd2O3. Oxygen dependence was observed in the UO2 samples with no dopant and increased as the temperature rose; in the doped fuels less dependence was observed. The addition of gadolinia into the UO2 matrix resulted in a significant decrease in the dissolution rate. The matrix stabilization effect resulting from the dopant proved even more beneficial in lowering the dissolution rate at higher temperatures and dissolved O2 concentrations in the leachate where the rates would typically be elevated.

  10. Sizing stack and battery of a fuel cell hybrid distribution truck

    NARCIS (Netherlands)

    Bram Veenhuizen; P.P.J. van den Bosch; Y. Shen; T. Hofman; Edwin Tazelaar

    2012-01-01

    Fuel cell hybrid vehicles are believed to provide a solution to cut down emissions in the long term. They provide local zero-emission propulsion and when the hydrogen as fuel is derived from renewable energy sources, fuel cell hybrids enable well-to-wheel zero-emission transportation,

  11. Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Samim Anghaie; Travis W. Knight; Johann Plancher; Reza Gouw

    2004-08-11

    An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors.

  12. Dissolved Air Flotation of arsenic adsorbent particles

    Directory of Open Access Journals (Sweden)

    M. Santander

    2015-04-01

    Full Text Available The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF and dissolved air flotation (DAF. A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic polyacrylamide (NALCO 9808 as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with flotation studies to determine the removal efficiency of adsorbents particles. The results achieved indicate that the adsorption kinetic of arsenic is very rapid and that in range of pH’s from 2 to 7 the adsorption percentages remain constant. The equilibrium conditions were achieved in 60 minutes and about 95% of arsenic was adsorbed when used an adsorbent concentration of 2 g/L and pH 6.3. The maximum adsorption capacity of adsorbent particles was 4.96 mg/g. The mean free energy of adsorption (E was found to be 2.63 kJ/mol, which suggests physisorption. The results of the flotation studies demonstrated that when synthetic effluents with 8.9 mg/L of arsenic were treated under the following experimental conditions; 2 g/L of adsorbent particles, 120 mg/L of Fe(III, 2 mg/L of Nalco 9808, 20 mg/L of sodium oleate, and 40% of recycle ratio in the DAF, it was possible to reach 98% of arsenic removal and 6.3 NTU of residual turbidity in clarified synthetic effluent.

  13. Dissolved organic carbon release by marine macrophytes

    Directory of Open Access Journals (Sweden)

    C. Barrón

    2012-02-01

    Full Text Available Estimates of dissolved organic carbon (DOC release by marine macrophyte communities (seagrass meadows and macroalgal beds were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP and net community production (NCP, however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.

  14. Alternative aviation turbine fuels

    Science.gov (United States)

    Grobman, J.

    1977-01-01

    The efficient utilization of fossil fuels by future jet aircraft may necessitate the broadening of current aviation turbine fuel specifications. The most significant changes in specifications would be an increased aromatics content and a higher final boiling point in order to minimize refinery energy consumption and costs. These changes would increase the freezing point and might lower the thermal stability of the fuel and could cause increased pollutant emissions, increased smoke and carbon formation, increased combustor liner temperatures, and poorer ignition characteristics. This paper discusses the effects that broadened specification fuels may have on present-day jet aircraft and engine components and the technology required to use fuels with broadened specifications.

  15. Modeling the Effect of Dissolved Hydrogen Sulfide on Mg2+-water Complex on Dolomite {104} Surfaces

    CERN Document Server

    Shen, Zhizhang; Brown, Philip E; Szlufarska, Izabela; Xu, Huifang

    2016-01-01

    The key kinetic barrier to dolomite formation is related to the surface Mg2+-H2O complex, which hinders binding of surface Mg2+ ions to the CO3 2- ions in solution. It has been proposed that this reaction can be catalyzed by dissolved hydrogen sulfide. To characterize the role of dissolved hydrogen sulfide in the dehydration of surface Mg 2+ ions, ab initio simulations based on density functional theory (DFT) were carried out to study the thermodynamics of competitive adsorption of hydrogen sulfide and water on dolomite (104) surfaces from solution. We find that water is thermodynamically more stable on the surface with the difference in adsorption energy of -13.6 kJ/mol (in vacuum) and -12.8 kJ/mol (in aqueous solution). However, aqueous hydrogen sulfide adsorbed on the surface increases the Mg2+-H2O distances on surrounding surface sites. Two possible mechanisms were proposed for the catalytic effects of adsorbed hydrogen sulfide on the anhydrous Ca-Mg-carbonate crystallization at low temperature.

  16. Functionalized polymers for binding to solutes in aqueous solutions

    Science.gov (United States)

    Smith, Barbara F.; Robison, Thomas W.

    2006-11-21

    A functionalized polymer for binding a dissolved molecule in an aqueous solution is presented. The polymer has a backbone polymer to which one or more functional groups are covalently linked. The backbone polymer can be such polymers as polyethylenimine, polyvinylamine, polyallylamine, and polypropylamine. These polymers are generally water-soluble, but can be insoluble when cross-linked. The functional group can be for example diol derivatives, polyol derivatives, thiol and dithiol derivatives, guest-host groups, affinity groups, beta-diphosphonic acids, and beta-diamides

  17. Diversity of Phosphate-Dissolving Microorganisms in Corn Rhizosphere

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiao-rong; LIN Qi-mei; LI Bao-guo

    2003-01-01

    Rhizosphere and nonrhizopshere soils were sampled during corn growth. Total, inorganic phosphate-dissolving and lecithin-mineralizing bacteria, fungi and actinomyctes were determined by plate counting method. Generally, the rhizosphere soil contained around 5 to 100 times more of these bacteria and fungi than the non-rhizosphere soil. However, the actinomycetes in the rhizosphere soil were significantly lower than those in the non-rhizosphere soil. The numbers of these microorganisms didnt significantly change during corn growth in the soils. However, the proportion of the phosphate-dissolving microorganisms in the total changed markedly during corn growth. Generally there were much higher percentages of phosphate-dissolving bacteria and phosphate-dissolving fungi in the rhizosphere soil than the nonrhizosphere soil. More than 90% of the fungi in rhizosphere dissolved inorganic phosphate at the seedling period, but this proportion declined to 20 %at the harvesting time. The community of phosphate-dissolving microorganisms also changed during corn growth. Bacillus was dominant in the nonrhizosphere soil. However, in the rhizosphere, Pseudomonas and Enterobacter became predominant. Penicillium and Streptomyces were the main fungi and actinomycetes capable of dissolving phosphate.

  18. Opportunities for portable Ballard Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Voss, H.H.; Huff, J.R. [Ballard Power Systems Inc., Burnaby, British Columbia (Canada)

    1996-12-31

    With the increasing proliferation and sophistication of portable electronic devices in both commercial and military markets, the need has arisen for small, lightweight power supplies that can provide increased operating life over those presently available. A solution to this power problem is the development of portable Ballard Fuel Cell power systems that operate with a hydrogen fuel source and air. Ballard has developed PEM fuel cell stacks and power systems in the 25 to 100 watt range for both of these markets. For military use, Ballard has teamed with Ball Corporation and Hydrogen Consultants, Inc. and has provided the Ballard Fuel Cell stack for an ambient PEM fuel cell power system for the DoD. The system provides power from idle to I 00 watts and has the capability of delivering overloads of 125 watts for short periods of time. The system is designed to operate over a wide range of temperature, relative humidity and altitude. Hydrogen is supplied as a compressed gas, metal hydride or chemical hydride packaged in a unit that is mated to the power/control unit. The hydrogen sources provide 1.5, 5 and 15 kWh of operation, respectively. The design of the fuel cell power system enables the unit to operate at 12 volts or 24 volts depending upon the equipment being used. For commercial applications, as with the military, fuel cell power sources in the 25 to 500 watt range will be competing with advanced batteries. Ambient PEM fuel cell designs and demonstrators are being developed at 25 watts and other low power levels. Goals are minimum stack volume and weight and greatly enhanced operating life with reasonable system weight and volume. This paper will discuss ambient PEM fuel cell designs and performance and operating parameters for a number of power levels in the multiwatt range.

  19. Multipolar Solutions

    CERN Document Server

    Quevedo, Hernando

    2012-01-01

    A class of exact solutions of the Einstein-Maxwell equations is presented which contains infinite sets of gravitoelectric, gravitomagnetic and electromagnetic multipole moments. The multipolar structure of the solutions indicates that they can be used to describe the exterior gravitational field of an arbitrarily rotating mass distribution endowed with an electromagnetic field. The presence of gravitational multipoles completely changes the structure of the spacetime because of the appearance of naked singularities in a confined spatial region. The possibility of covering this region with interior solutions is analyzed in the case of a particular solution with quadrupole moment.

  20. Design of Uranium So