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Sample records for coated particle fuel

  1. Preparing oxidizer coated metal fuel particles

    NASA Technical Reports Server (NTRS)

    Shafer, J. I.; Simmons, G. M. (Inventor)

    1974-01-01

    A solid propellant composition of improved efficiency is described which includes an oxidizer containing ammonium perchlorate, and a powered metal fuel, preferably aluminum or beryllium, in the form of a composite. The metal fuel is contained in the crystalline lattice framework of the oxidizer, as well as within the oxidizer particles, and is disposed in the interstices between the oxidizer particles of the composition. The propellant composition is produced by a process comprising the crystallization of ammonium perchlorate in water, in the presence of finely divided aluminum or beryllium. A suitable binder is incorporated in the propellant composition to bind the individual particles of metal with the particles of oxidizer containing occluded metal.

  2. Diagnostics of coated fuel particles by neutron and synchrotron radiography

    SciTech Connect

    Momot, G. V.; Podurets, K. M.; Pogorelyi, D. K.; Somenkov, V. A.; Yakovenko, E. V.

    2011-12-15

    The nondestructive monitoring of coated fuel particles has been performed using contact neutron radiography and refraction radiography based on synchrotron radiation. It is shown that these methods supplement each other and have a high potential for determining the sizes, densities, and isotopic composition of the particle components.

  3. Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

    SciTech Connect

    Scott Ploger; Paul Demkowicz; John Hunn; Robert Morris

    2012-10-01

    The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak burnup of 19.5% FIMA with no in-pile failures observed out of 3×105 total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Five compacts have been examined so far, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose between approximately 40-80 individual particles on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer-IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, over 800 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in approximately 23% of the particles, and these fractures often resulted in unconstrained kernel swelling into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer-IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only three particles, all in conjunction with IPyC-SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures, IPyC-SiC debonds, and SiC fractures.

  4. Microscopic analysis of irradiated AGR-1 coated particle fuel compacts

    SciTech Connect

    Scott A. Ploger; Paul A. Demkowicz; John D. Hunn; Jay S. Kehn

    2014-05-01

    The AGR-1 experiment involved irradiation of 72 TRISO-coated particle fuel compacts to a peak compact-average burnup of 19.5% FIMA with no in-pile failures observed out of 3 x 105 total particles. Irradiated AGR-1 fuel compacts have been cross-sectioned and analyzed with optical microscopy to characterize kernel, buffer, and coating behavior. Six compacts have been examined, spanning a range of irradiation conditions (burnup, fast fluence, and irradiation temperature) and including all four TRISO coating variations irradiated in the AGR-1 experiment. The cylindrical specimens were sectioned both transversely and longitudinally, then polished to expose from 36 to 79 individual particles near midplane on each mount. The analysis focused primarily on kernel swelling and porosity, buffer densification and fracturing, buffer–IPyC debonding, and fractures in the IPyC and SiC layers. Characteristic morphologies have been identified, 981 particles have been classified, and spatial distributions of particle types have been mapped. No significant spatial patterns were discovered in these cross sections. However, some trends were found between morphological types and certain behavioral aspects. Buffer fractures were found in 23% of the particles, and these fractures often resulted in unconstrained kernel protrusion into the open cavities. Fractured buffers and buffers that stayed bonded to IPyC layers appear related to larger pore size in kernels. Buffer–IPyC interface integrity evidently factored into initiation of rare IPyC fractures. Fractures through part of the SiC layer were found in only four classified particles, all in conjunction with IPyC–SiC debonding. Compiled results suggest that the deliberate coating fabrication variations influenced the frequencies of IPyC fractures and IPyC–SiC debonds.

  5. Irradiation performance of HTGR coated particle fuels with ZrC coatings

    SciTech Connect

    Homan, F J; Kania, M J

    1985-01-01

    During the past 25 years of fuel development for the High-Temperature Gas-Cooled Reactor (HTGR) the Triso particle has evolved as the favored design to optimize economics and performance. The Triso particle consists of a kernel (fissile or fertile), a buffer [porous pyrocarbon (PyC)], an inner PyC layer, a dense SiC layer, and an outer PyC layer. Consideration has been given to replacing the SiC layer with ZrC for applications requiring very high fuel operating temperatures. Other designs using ZrC have also been considered and tested. This report reviews all the irradiation testing data collected within the US program on HTGR fuel particles with ZrC coatings. Fission product retentiveness of particles with ZrC coatings has generally been inferior to that of similar particles with the Triso design, but it is emphasized that the fabrication of ZrC coatings has not been optimized to nearly the extent of that of SiC coatings.

  6. Development of improved TRISO-P fuel particle P-PyC coating

    SciTech Connect

    Adams, C.C.

    1988-04-29

    Low defect fuels are required for the MHTGR to meet tighter fuel performance for this reactor design (Ref. 1). Exposed heavy metal (HM) contamination levels must be reduced to {le} 1E-5 fraction. Particle coating breakage during the fuel compact fabrication process has been shown to be a major source of HM contamination in the final fuel compacts. Excessive forces are experienced by the coated fuel particles during matrix injection, which leads to coating failure. Adding a sacrificial, low Young`s modulus, overcoating of low density PyC in a fluidized particle bed, was shown to greatly increase the crush strength of TRISO coated fuel particles in 1986 studies (Ref. 2). The new TRISO coated fuel particle design was designated the TRISO-P coated fuel particle type. In 1987, the TRISO-P particle type was used to produce low defect fuel compacts for irradiation in the HRB-21 Capsule (Ref. 3). However, the exposed HM contamination levels for that fuel barely met the product specification limit of {le} 1.0E-5. The small margin of safety between product quality and the specification limit dictated that additional process development of the TRISO-P particle design must be conducted. This document discusses the program scope, requirements, documentation and schedule.

  7. SP-100 coated-particle fuel development. Phase I. Final report

    SciTech Connect

    Not Available

    1983-03-01

    This document is the final report of Phase I of the SP-100 Coated-Particle Fuel Development Program conducted by GA Technologies Inc. for the US Department of Energy under contract DE-AT03-82SF11690. The general objective of the study conducted between September and December 1982 was to evaluate coated-particle type fuel as an alternate or backup fuel to the UO/sub 2/ tile-and-fin arrangement currently incorporated into the reference design of the SP-100 reactor core. This report presents and discusses the following topics in the order listed: the need for an alternative fuel for the SP-100 nuclear reactor; an abbreviated description of the reference and coated-particle fuel module concepts; the bases and results of the study and analysis leading to the preliminary design of a coated particle suitable for the SP-100 space power reactor; incorporation of the fuel particles into compacts and heat-pipe-cooled modules; initial efforts and plans to fabricate coated-particle fuel and fuel compacts; the design and performance of the proposed alternative core relative that of the reference fuel; and a summary of critical issues and conclusions consistent with the level of effort and duration of the study.

  8. Current Development Status of a Particle Size Analyzer for Coated Particle Fuel

    SciTech Connect

    Nelson, Andrew T; Hunn, John D; Karnowski, Thomas Paul

    2007-08-01

    Work was performed to develop a prototype Particle Size Analyzer (PSA) for application to coated particle fuel characterization. This system was based on a light obscuration method and targeted towards high throughput analysis. Although never matured to the point of replacing existing lower throughput optical microscopy shadowgraph methods, the system was successfully applied to automating the counting of large particle samples for increased accuracy in calculating mean particle properties based on measurements of multiparticle samples. The measurement of particle size with the PSA was compared to current shadowgraph techniques and found to result in considerably greater throughput at the cost of larger measurement uncertainty. The current algorithm used by the PSA is more sensitive to particle shape and this is a likely cause of the greater uncertainty when attempting to measure average particle diameter. The use of the PSA to measure particle shape will require further development. Particle transport through the PSA and stability of the light source/detector are key elements in the successful application of this technique. A number of system pitfalls were studied and addressed.

  9. Coated Particle and Deep Burn Fuels Monthly Highlights December 2010

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-01-01

    During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for November 2010, ORNL/TM-2010/323, was distributed to program participants on December 9, 2010. The final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Core Design Optimization in the HTR (high temperature helium-cooled reactor) Pebble Bed Design (INL), (c) Radiation Damage and Properties; (2) TRISO (tri-structural isotropic) Development - (a) TRU (transuranic elements) Kernel Development, (b) Coating Development; (3) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing (ORNL); (4) Fuel Performance and Analytical Analysis - Fuel Performance Modeling (ORNL).

  10. Stress Analysis of Coated Particle Fuel in the Deep-Burn Pebble Bed Reactor Design

    SciTech Connect

    B. Boer; A. M. Ougouag

    2010-05-01

    High fuel temperatures and resulting fuel particle coating stresses can be expected in a Pu and minor actinide fueled Pebble Bed Modular Reactor (400 MWth) design as compared to the ’standard’ UO2 fueled core. The high discharge burnup aimed for in this Deep-Burn design results in increased power and temperature peaking in the pebble bed near the inner and outer reflector. Furthermore, the pebble power in a multi-pass in-core pebble recycling scheme is relatively high for pebbles that make their first core pass. This might result in an increase of the mechanical failure of the coatings, which serve as the containment of radioactive fission products in the PBMR design. To investigate the integrity of the particle fuel coatings as a function of the irradiation time (i.e. burnup), core position and during a Loss Of Forced Cooling (LOFC) incident the PArticle STress Analysis code (PASTA) has been coupled to the PEBBED code for neutronics, thermal-hydraulics and depletion analysis of the core. Two deep burn fuel types (Pu with or without initial MA fuel content) have been investigated with the new code system for normal and transient conditions including the effect of the statistical variation of thickness of the coating layers.

  11. Thermo-Mechanical Analysis of Coated Particle Fuel Experiencing a Fast Control Rod Ejection Transient

    SciTech Connect

    Ortensi, J.; Brian Boer; Abderrafi M. Ougouag

    2010-10-01

    A rapid increase of the temperature and the mechanical stress is expected in TRISO coated particle fuel that experiences a fast Total Control Rod Ejection (CRE) transient event. During this event the reactor power in the pebble bed core increases significantly for a short time interval. The power is deposited instantly and locally in the fuel kernel. This could result in a rapid increase of the pressure in the buffer layer of the coated fuel particle and, consequently, in an increase of the coating stresses. These stresses determine the mechanical failure probability of the coatings, which serve as the containment of radioactive fission products in the Pebble Bed Reactor (PBR). A new calculation procedure has been implemented at the Idaho National Laboratory (INL), which analyzes the transient fuel performance behavior of TRISO fuel particles in PBRs. This early capability can easily be extended to prismatic designs, given the availability of neutronic and thermal-fluid solvers. The full-core coupled neutronic and thermal-fluid analysis has been modeled with CYNOD-THERMIX. The temperature fields for the fuel kernel and the particle coatings, as well as the gas pressures in the buffer layer, are calculated with the THETRIS module explicitly during the transient calculation. Results from this module are part of the feedback loop within the neutronic-thermal fluid iterations performed for each time step. The temperature and internal pressure values for each pebble type in each region of the core are then input to the PArticle STress Analysis (PASTA) code, which determines the particle coating stresses and the fraction of failed particles. This paper presents an investigation of a Total Control Rod Ejection (TCRE) incident in the 400 MWth Pebble Bed Modular reactor design using the above described calculation procedure. The transient corresponds to a reactivity insertion of $3 (~2000 pcm) reaching 35 times the nominal power in 0.5 seconds. For each position in the core

  12. Combustion characteristics of GAP-coated boron particles and the fuel-rich solid propellant

    SciTech Connect

    Shyu, I.M.; Liu, T.K.

    1995-03-01

    A process was employed that permits the coating of energetic glycidyl azide polymer (GAP) on the boron surface. Ignition and combustion behavior of single particle pure crystalline boron and GAP-coated boron at atmospheric pressure was studied experimentally by injecting the particles into the stream of hot gaseous environment of a flat-flame burner using premixed propane-oxygen-nitrogen gases. Chopped streak photographic observation was used to measure the ignition and combustion time. The flame temperature was fixed around 2,343 K, but under wider O{sub 2} level range than previous investigations. Measurement results show that GAP coating can shorten boron particle ignition delay time, however, the effect diminishes as the O{sub 2} level in combustion gas decreases. Possible mechanisms based on relevant reactions and heat effects were proposed. Combustion characteristics of fuel-rich solid propellants based on GAP-coated amorphous boron particles and uncoated ones were compared using different techniques such as combustion phenomena observations by a windowed strand burner, quenched propellant surface morphology analysis by scanning electron microscope, and combustion residues size analysis from the quenched particle collection bomb experiments. It was concluded that GAP-coated amorphous-boron-based fuel-rich propellants exhibit more vigorous combustion phenomena, higher burning rates, and a lesser extent of residue agglomeration than the uncoated baseline propellant. Moreover, reaction mechanisms were proposed to elucidate the combustion products obtained in this study.

  13. Evaluation of design parameters for TRISO-coated fuel particles to establish manufacturing critical limits using PARFUME

    NASA Astrophysics Data System (ADS)

    Skerjanc, William F.; Maki, John T.; Collin, Blaise P.; Petti, David A.

    2016-02-01

    The success of modular high temperature gas-cooled reactors is highly dependent on the performance of the tristructural-isotopic (TRISO) coated fuel particle and the quality to which it can be manufactured. During irradiation, TRISO-coated fuel particles act as a pressure vessel to contain fission gas and mitigate the diffusion of fission products to the coolant boundary. The fuel specifications place limits on key attributes to minimize fuel particle failure under irradiation and postulated accident conditions. PARFUME (an integrated mechanistic coated particle fuel performance code developed at the Idaho National Laboratory) was used to calculate fuel particle failure probabilities. By systematically varying key TRISO-coated particle attributes, failure probability functions were developed to understand how each attribute contributes to fuel particle failure. Critical manufacturing limits were calculated for the key attributes of a low enriched TRISO-coated nuclear fuel particle with a kernel diameter of 425 μm. These critical manufacturing limits identify ranges beyond where an increase in fuel particle failure probability is expected to occur.

  14. Evaluation of design parameters for TRISO-coated fuel particles to establish manufacturing critical limits using PARFUME

    DOE PAGES

    Skerjanc, William F.; Maki, John T.; Collin, Blaise P.; ...

    2015-12-02

    The success of modular high temperature gas-cooled reactors is highly dependent on the performance of the tristructural-isotopic (TRISO) coated fuel particle and the quality to which it can be manufactured. During irradiation, TRISO-coated fuel particles act as a pressure vessel to contain fission gas and mitigate the diffusion of fission products to the coolant boundary. The fuel specifications place limits on key attributes to minimize fuel particle failure under irradiation and postulated accident conditions. PARFUME (an integrated mechanistic coated particle fuel performance code developed at the Idaho National Laboratory) was used to calculate fuel particle failure probabilities. By systematically varyingmore » key TRISO-coated particle attributes, failure probability functions were developed to understand how each attribute contributes to fuel particle failure. Critical manufacturing limits were calculated for the key attributes of a low enriched TRISO-coated nuclear fuel particle with a kernel diameter of 425 μm. As a result, these critical manufacturing limits identify ranges beyond where an increase in fuel particle failure probability is expected to occur.« less

  15. Evaluation of design parameters for TRISO-coated fuel particles to establish manufacturing critical limits using PARFUME

    SciTech Connect

    Skerjanc, William F.; Maki, John T.; Collin, Blaise P.; Petti, David A.

    2015-12-02

    The success of modular high temperature gas-cooled reactors is highly dependent on the performance of the tristructural-isotopic (TRISO) coated fuel particle and the quality to which it can be manufactured. During irradiation, TRISO-coated fuel particles act as a pressure vessel to contain fission gas and mitigate the diffusion of fission products to the coolant boundary. The fuel specifications place limits on key attributes to minimize fuel particle failure under irradiation and postulated accident conditions. PARFUME (an integrated mechanistic coated particle fuel performance code developed at the Idaho National Laboratory) was used to calculate fuel particle failure probabilities. By systematically varying key TRISO-coated particle attributes, failure probability functions were developed to understand how each attribute contributes to fuel particle failure. Critical manufacturing limits were calculated for the key attributes of a low enriched TRISO-coated nuclear fuel particle with a kernel diameter of 425 μm. As a result, these critical manufacturing limits identify ranges beyond where an increase in fuel particle failure probability is expected to occur.

  16. Experimental test plan: USDOE/JAERI collaborative program for the coated particle fuel performance test

    SciTech Connect

    Kania, M.J.; Fukuda, K.

    1989-12-01

    This document describes the coated-particle fuel performance test agreed to under Annex 2 of the arrangement between the US Department of Energy and the Japan Atomic Energy Research Institute on cooperation in research and development regarding high-temperature gas-cooled reactors (HTGRs). The test will evaluate the behavior of reference fuel compacts containing coated-particle fuels fabricated according to the specifications for the US Modular HTGR and the Japanese High-Temperature Engineering Test Reactor (HTTR) concepts. Two experimental capsules, HRB-21 and HRB-22, are being tested. Capsule HRB-21 contains only US reference fuel, and HRB-22 contains only JAERI reference fuel. Both capsules will be irradiated in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Capsule HRB-21 will be operated at a mean volumetric fuel temperature of 975{degrees}C and will achieve a peak fissile burnup of 26% fissions per initial metal atom (FIMA) and a fast fluence of {le}4.5 {times} 10{sup 25} neutrons/m{sup 2}. Capsule HRB-22 will be operated at a mean centerline fuel temperature of 1250 to 1300{degrees}C and will achieve a peak fissile burnup of 5.5% FIMA and a fast fluence of 1.7 {times} 10{sup 25} neutrons/m{sup 2}. Performance of the fuels during irradiation will be closely monitored using on-line fission gas surveillance. Following irradiation, both capsules will undergo detailed examinations and core heatup simulation testing. Results from in-reactor monitoring and postirradiation testing will be analyzed to comparatively assess US and Japanese coated-particle fuel performance. 3 refs., 9 figs., 10 tabs.

  17. The Challenges Associated with High Burnup and High Temperature for UO2 TRISO-Coated Particle Fuel

    SciTech Connect

    David Petti; John Maki

    2005-02-01

    The fuel service conditions for the DOE Next Generation Nuclear Plant (NGNP) will be challenging. All major fuel related design parameters (burnup, temperature, fast neutron fluence, power density, particle packing fraction) exceed the values that were qualified in the successful German UO2 TRISO-coated particle fuel development program in the 1980s. While TRISO-coated particle fuel has been irradiated at NGNP relevant levels for two or three of the design parameters, no data exist for TRISO-coated particle fuel for all five parameters simultaneously. Of particular concern are the high burnup and high temperatures expected in the NGNP. In this paper, where possible, we evaluate the challenges associated with high burnup and high temperature quantitatively by examining the performance of the fuel in terms of different known failure mechanisms. Potential design solutions to ameliorate the negative effects of high burnup and high temperature are also discussed.

  18. Device for fracturing silicon-carbide coatings on nuclear-fuel particles

    DOEpatents

    Turner, L.J.; Willey, M.G.; Tiegs, S.M.; Van Cleve, J.E. Jr.

    This invention is a device for fracturing particles. It is designed especially for use in hot cells designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel materials, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

  19. Method for fracturing silicon-carbide coatings on nuclear-fuel particles

    DOEpatents

    Turner, Lloyd J.; Willey, Melvin G.; Tiegs, Sue M.; Van Cleve, Jr., John E.

    1982-01-01

    This invention is a device for fracturing particles. It is designed especially for use in "hot cells" designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel material, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

  20. Key Differences in the Fabrication, Irradiation, and Safety Testing of U.S. and German TRISO-coated Particle Fuel and Their Implications on Fuel Performance

    SciTech Connect

    Petti, David Andrew; Maki, John Thomas; Buongiorno, Jacopo; Hobbins, Richard Redfield

    2002-06-01

    High temperature gas reactor technology is achieving a renaissance around the world. This technology relies on high quality production and performance of coated particle fuel. Historically, the irradiation performance of TRISO-coated gas reactor particle fuel in Germany has been superior to that in the United States. German fuel generally displayed in-pile gas release values that were three orders of magnitude lower than U.S. fuel. Thus, we have critically examined the TRISO-coated fuel fabrication processes in the U.S. and Germany and the associated irradiation database with a goal of understanding why the German fuel behaves acceptably, why the U.S. fuel has not faired as well, and what process/ production parameters impart the reliable performance to this fuel form. The postirradiation examination results are also reviewed to identify failure mechanisms that may be the cause of the poorer U.S. irradiation performance. This comparison will help determine the roles that particle fuel process/product attributes and irradiation conditions (burnup, fast neutron fluence, temperature, and degree of acceleration) have on the behavior of the fuel during irradiation and provide a more quantitative linkage between acceptable processing parameters, as-fabricated fuel properties and subsequent in-reactor performance.

  1. In-pile test results of U-silicide or U-nitride coated U-7Mo particle dispersion fuel in Al

    NASA Astrophysics Data System (ADS)

    Kim, Yeon Soo; Park, J. M.; Lee, K. H.; Yoo, B. O.; Ryu, H. J.; Ye, B.

    2014-11-01

    U-silicide or U-nitride coated U-Mo particle dispersion fuel in Al (U-Mo/Al) was in-pile tested to examine the effectiveness of the coating as a diffusion barrier between the U-7Mo fuel kernels and Al matrix. This paper reports the PIE data and analyses focusing on the effectiveness of the coating in terms of interaction layer (IL) growth and general fuel performance. The U-silicide coating showed considerable success, but it also provided evidence for additional improvement for coating process. The U-nitride coated specimen showed largely inefficient results in reducing IL growth. From the test, important observations were also made that can be utilized to improve U-Mo/Al fuel performance. The heating process for coating turned out to be beneficial to suppress fuel swelling. The use of larger fuel particles confirmed favorable effects on fuel performance.

  2. Uranium extraction from TRISO-coated fuel particles using supercritical CO2 containing tri-n-butyl phosphate.

    PubMed

    Zhu, Liyang; Duan, Wuhua; Xu, Jingming; Zhu, Yongjun

    2012-11-30

    High-temperature gas-cooled reactors (HTGRs) are advanced nuclear systems that will receive heavy use in the future. It is important to develop spent nuclear fuel reprocessing technologies for HTGR. A new method for recovering uranium from tristructural-isotropic (TRISO-) coated fuel particles with supercritical CO(2) containing tri-n-butyl phosphate (TBP) as a complexing agent was investigated. TRISO-coated fuel particles from HTGR fuel elements were first crushed to expose UO(2) pellet fuel kernels. The crushed TRISO-coated fuel particles were then treated under O(2) stream at 750°C, resulting in a mixture of U(3)O(8) powder and SiC shells. The conversion of U(3)O(8) into solid uranyl nitrate by its reaction with liquid N(2)O(4) in the presence of a small amount of water was carried out. Complete conversion was achieved after 60 min of reaction at 80°C, whereas the SiC shells were not converted by N(2)O(4). Uranyl nitrate in the converted mixture was extracted with supercritical CO(2) containing TBP. The cumulative extraction efficiency was above 98% after 20 min of online extraction at 50°C and 25 MPa, whereas the SiC shells were not extracted by TBP. The results suggest an attractive strategy for reprocessing spent nuclear fuel from HTGR to minimize the generation of secondary radioactive waste.

  3. Nickel-Coated Aluminum Particles: A Promising Fuel for Mars Missions

    NASA Technical Reports Server (NTRS)

    Shafirovich, Evgeny; Varma, Arvind

    2004-01-01

    Combustion of metals in carbon dioxide is a promising source of energy for propulsion on Mars. This approach is based on the ability of some metals (e.g. Mg, Al) to burn in CO2 atmosphere and suggests use of the Martian carbon dioxide as an oxidizer in jet or rocket engines. Analysis shows that CO2/metal propulsion will reduce significantly the mass of propellant transported from Earth for long-range mobility on Mars and sample return missions. Recent calculations for the near-term missions indicate that a 200-kg ballistic hopper with CO2/metal rocket engines and a CO2 acquisition unit can perform 10-15 flights on Mars with the total range of 10-15 km, i.e. fulfill the exploration program typically assigned for a rover. Magnesium is currently recognized as a candidate fuel for such engines owing to easy ignition and fast burning in CO2. Aluminum may be more advantageous if a method for reducing its ignition temperature is found. Coating it by nickel is one such method. It is known that a thin nickel layer of nickel on the surface of aluminum particles can prevent their agglomeration and simultaneously facilitate their ignition, thus increasing the efficiency of aluminized propellants. Combustion of single Ni-coated Al particles in different gas environments (O2, CO2, air) was studied using electrodynamic levitation and laser ignition. It was shown that the combustion mechanisms depend on the ambient atmosphere. Combustion in CO2 is characterized by the smaller size and lower brightness of flame than in O2, and by phenomena such as micro-flashes and fragment ejection. The size and brightness of flame gradually decrease as the particle burns.

  4. Development of Improved Models and Designs for Coated-Particle Gas Reactor Fuels (I-NERI Annual Report)

    SciTech Connect

    Petti, David Andrew; Maki, John Thomas; Languille, Alain; Martin, Philippe; Ballinger, Ronald

    2002-11-01

    The objective of this INERI project is to develop improved fuel behavior models for gas reactor coated particle fuels and to develop improved coated-particle fuel designs that can be used reliably at very high burnups and potentially in fast gas-cooled reactors. Thermomechanical, thermophysical, and physiochemical material properties data were compiled by both the US and the French and preliminary assessments conducted. Comparison between U.S. and European data revealed many similarities and a few important differences. In all cases, the data needed for accurate fuel performance modeling of coated particle fuel at high burnup were lacking. The development of the INEEL fuel performance model, PARFUME, continued from earlier efforts. The statistical model being used to simulate the detailed finite element calculations is being upgraded and improved to allow for changes in fuel design attributes (e.g. thickness of layers, dimensions of kernel) as well as changes in important material properties to increase the flexibility of the code. In addition, modeling of other potentially important failure modes such as debonding and asphericity was started. A paper on the status of the model was presented at the HTR-2002 meeting in Petten, Netherlands in April 2002, and a paper on the statistical method was submitted to the Journal of Nuclear Material in September 2002. Benchmarking of the model against Japanese and an older DRAGON irradiation are planned. Preliminary calculations of the stresses in a coated particle have been calculated by the CEA using the ATLAS finite element model. This model and the material properties and constitutive relationships will be incorporated into a more general software platform termed Pleiades. Pleiades will be able to analyze different fuel forms at different scales (from particle to fuel body) and also handle the statistical variability in coated particle fuel. Diffusion couple experiments to study Ag and Pd transport through SiC were

  5. Method of evaluating the integrity of the outer carbon layer of triso-coated reactor fuel particles

    DOEpatents

    Caputo, Anthony J.; Costanzo, Dante A.; Lackey, Jr., Walter J.; Layton, Frank L.; Stinton, David P.

    1980-01-01

    This invention relates to a method for determining defective final layers of carbon on triso-coated fuel particles and the like. Samples of the particles are subjected to a high temperature treatment with gaseous chlorine and thereafter radiographed. The chlorine penetrates through any defective carbon layer and reacts with the underlying silicon carbide resulting in the volatilization of the silicon as SiCl.sub.4 leaving carbon as a porous layer. This porous carbon layer is easily detected by the radiography.

  6. Particle fuel bed tests

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Savino, J.M.

    1985-01-01

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H/sub 2/ for 12 hours with no visible reaction or weight loss.

  7. Key differences in the fabrication, irradiation and high temperature accident testing of US and German TRISO-coated particle fuel, and their implications on fuel performance

    SciTech Connect

    Petti, David Andrew; Buongiorno, Jacopo; Maki, John Thomas; Hobbins, Richard Redfield

    2003-06-01

    Historically, the irradiation performance of TRISO-coated gas reactor particle fuel in Germany has been superior to that in the US. German fuel generally has displayed gas release values during irradiation three orders of magnitude lower than US fuel. Thus, we have critically examined the TRISO-coated fuel fabrication processes in the US and Germany and the associated irradiation database with a goal of understanding why the German fuel behaves acceptably, why the US fuel has not faired as well, and what process/production parameters impart the reliable performance to this fuel form. The postirradiation examination results are also reviewed to identify failure mechanisms that may be the cause of the poorer US irradiation performance. This comparison will help determine the roles that particle fuel process/product attributes and irradiation conditions (burnup, fast neutron fluence, temperature, degree of acceleration) have on the behavior of the fuel during irradiation and provide a more quantitative linkage between acceptable processing parameters, as-fabricated fuel properties and subsequent in-reactor performance.

  8. Development of Improved Models and Designs for Coated-Particle Gas Reactor Fuels -- Final Report under the International Nuclear Energy Research Initiative (I-NERI)

    SciTech Connect

    Petti, David; Martin, Philippe; Phelip, Mayeul; Ballinger, Ronald

    2004-12-01

    The objective of this INERI project was to develop improved fuel behavior models for gas reactor coated-particle fuels and to explore improved coated-particle fuel designs that could be used reliably at very high burnups and potentially in gas-cooled fast reactors. Project participants included the Idaho National Engineering Laboratory (INEEL), Centre Étude Atomique (CEA), and the Massachusetts Institute of Technology (MIT). To accomplish the project objectives, work was organized into five tasks.

  9. Fission product retention in TRISCO coated UO sub 2 particle fuels subjected to HTR simulated core heating tests

    SciTech Connect

    Baldwin, C.A.; Kania, M.J.

    1990-11-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600{degree}C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800{degree}C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800{degree}C and above may exist. 6 refs., 6 figs., 4 tabs.

  10. Nickel-coated Aluminum Particles: A Promising Fuel for Mars Missions

    NASA Technical Reports Server (NTRS)

    Shafirovich, Evgeny; Varma, Arvind

    2004-01-01

    Combustion of metals in carbon dioxide is a promising source of energy for propulsion on Mars. This approach is based on the ability of some metals (e.g. Mg, Al) to burn in CO2 atmosphere and suggests use of the Martian carbon dioxide as an oxidizer in jet or rocket engines. Analysis shows that CO2/metal propulsion will reduce significantly the mass of propellant transported from Earth for long-range mobility on Mars and sample return missions. Recent calculations for the near-term missions indicate that a 200-kg ballistic hopper with CO2/metal rocket engines and a CO2 acquisition unit can perform 10-15 flights on Mars with the total range of 10-15 km, i.e. fulfill the exploration program typically assigned for a rover. Magnesium is currently recognized as a candidate fuel for such engines owing to easy ignition and fast burning in CO2. Aluminum may be more advantageous if a method for reducing its ignition temperature is found. Coating it by nickel is one such method. It is known that a thin nickel layer of nickel on the surface of aluminum particles can prevent their agglomeration and simultaneously facilitate their ignition, thus increasing the efficiency of aluminized propellants.

  11. Simulated fission product-SiC interaction in Triso-coated LEU or MEU HTGR fuel particles

    SciTech Connect

    Pearson, R.L.; Lindemer, T.B.; Beahm, E.C.

    1980-11-01

    Proliferation issues relating to the use of highly enriched uranium (HEU) have led to an evaluation of the fission product-SiC interaction problems that might arise if low enriched uranium (LEU) or medium enriched uranium (MEU) were used as fissile fuel in HTGR systems. Simulated Triso-coated UO/sub 2/, UC/sub 2/, and UO/sub 2//UC/sub 2/ particles mixed with varying amounts of Mo, Ru, Rh, Pd, Ag, and Cd were prepared. These fission products were chosen because, after full burnup, their concentrations are higher in LEU and MEU fuels than in HEU fuel. After the particles were heat treated in the laboratory, their behavior was examined by use of metallography, scanning electron microscopy, and electron microprobe x-ray analysis.

  12. First elevated-temperature performance testing of coated particle fuel compacts from the AGR-1 irradiation experiment

    SciTech Connect

    Charles A. Baldwin; John D. Hunn; Robert N. Morris; Fred C. Montgomery; Chinthaka M. Silva; Paul A. Demkowicz

    2014-05-01

    In the AGR-1 irradiation experiment, 72 coated-particle fuel compacts were taken to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures. This paper discusses the first post-irradiation test of these mixed uranium oxide/uranium carbide fuel compacts at elevated temperature to examine the fuel performance under a simulated depressurized conduction cooldown event. A compact was heated for 400 h at 1600 degrees C. Release of 85Kr was monitored throughout the furnace test as an indicator of coating failure, while other fission product releases from the compact were periodically measured by capturing them on exchangeable, water-cooled deposition cups. No coating failure was detected during the furnace test, and this result was verified by subsequent electrolytic deconsolidation and acid leaching of the compact, which showed that all SiC layers were still intact. However, the deposition cups recovered significant quantities of silver, europium, and strontium. Based on comparison of calculated compact inventories at the end of irradiation versus analysis of these fission products released to the deposition cups and furnace internals, the minimum estimated fractional losses from the compact during the furnace test were 1.9 x 10-2 for silver, 1.4 x 10-3 for europium, and 1.1 x 10-5 for strontium. Other post-irradiation examination of AGR-1 compacts indicates that similar fractions of europium and silver may have already been released by the intact coated particles during irradiation, and it is therefore likely that the detected fission products released from the compact in this 1600 degrees C furnace test were from residual fission products in the matrix. Gamma analysis of coated particles deconsolidated from the compact after the heating test revealed that silver content within each particle varied considerably; a result that is probably not related to the furnace test, because it has also been observed in other as-irradiated AGR-1 compacts. X

  13. Coated Particle Fuel and Deep Burn Program Monthly Highlights January 2011

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-02-01

    During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for December 2010, ORNL/TM-2011/10, was distributed to program participants on January 12, 2011. As reported last month, the final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Actinide and Fission Product Transport, (c) Radiation Damage and Properties; (2) TRU (transuranic elements) TRISO (tri-structural isotropic) Development - (a) TRU Kernel Development, (b) Coating Development; (3) Advanced TRISO Applications - Metal Matrix Fuels for LWR; (4) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing; (5) Fuel Performance and Analytical Analysis - Fuel Performance Modeling.

  14. Coated Particle Fuel and Deep Burn Program Monthly Highlights March 2011

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-04-01

    During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for February 2011, ORNL/TM-2011/71, was distributed to program participants on March 8, 2011. As reported previously, the final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Thermomechanical Behavior, (c) Actinide and Fission Product Transport, (d) Radiation Damage and Properties; (2) TRU (transuranic elements) TRISO (tri-structural isotropic) Development - (a) TRU Kernel Development, (b) Coating Development; (3) Advanced TRISO Applications - Metal Matrix Fuels for LWR; (4) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing; and (5) Fuel Performance and Analytical Analysis - Fuel Performance Modeling.

  15. Coated Particle Fuel and Deep Burn Program Monthly Highlights February 2011

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-03-01

    During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for January 2010, ORNL/TM-2011/30, was distributed to program participants on February 8, 2011. As reported previously, the final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Actinide and Fission Product Transport, (c) Radiation Damage and Properties; (2) TRU (transuranic elements) TRISO (tri-structural isotropic) Development - (a) TRU Kernel Development, (b) Coating Development; (3) Advanced TRISO Applications - Metal Matrix Fuels for LWR; (4) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing; and (5) Fuel Performance and Analytical Analysis - Fuel Performance Modeling.

  16. Coated Particle Fuel and Deep Burn Program Monthly Highlights June 2011

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-07-01

    During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for May 2011, ORNL/TM-2011/126, was distributed to program participants on June 9, 2011. As reported previously, the final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Fuel Performance Modeling - Fuel Performance Analysis; (2) Thermochemical Data and Model Development - (a) Thermochemical Behavior, (b) Thermomechanical Modeling, (c) Actinide and Fission Product Transport; (3) TRU (transuranic elements) TRISO (tri-structural isotropic) Development - (a) TRU Kernel Development, (b) Coating Development; and (4) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing.

  17. Preparation of UC0.07-0.10N0.90-0.93 spheres for TRISO coated fuel particles

    SciTech Connect

    Collins, Jack Lee; Hunt, Rodney Dale; Johnson, Jared A; Silva, Chinthaka M; Lindemer, Terrence

    2014-01-01

    The U.S. Department of Energy is considering a new nuclear fuel, which should be much more impervious during a loss of coolant accident. The fuel would consist of tristructural isotropic coated particles with dense uranium nitride (UN) kernels. The objectives of this effort are to make uranium oxide microspheres with adequately dispersed carbon nanoparticles and to convert these microspheres into UN kernels. Recent improvements to internal gelation process were successfully applied to the production of uranium gel spheres with different concentrations of carbon black. After the spheres were washed, a simple, two-step heat profile was used to produce kernels with a chemical composition of UC0.07 0.10N0.90 0.93. The first step involved heating the microspheres to 2023 K in a vacuum, and in the second step, the microspheres were held at 1873 K for 6 hrs in nitrogen.

  18. Coated Particle Fuel and Deep Burn Program Monthly Highlights April 2011

    SciTech Connect

    Snead, Lance Lewis; Bell, Gary L; Besmann, Theodore M

    2011-05-01

    The baseline change proposal BCP-FCRD-11026 submitted to change the due date for M21AF080202 'Demonstrate fabrication of Transuranic kernels of Plutonium-239/3.5at%Neptunium-237 using newly installed glove box facilities in ORNL 7930 hot cell complex' from 4/25/11 to 3/30/12 was approved this month. During FY 2011 the CP & DB Program will report Highlights on a monthly basis, but will no longer produce Quarterly Progress Reports. Technical details that were previously included in the quarterly reports will be included in the appropriate Milestone Reports that are submitted to FCRD Program Management. These reports will also be uploaded to the Deep Burn website. The Monthly Highlights report for March 2011, ORNL/TM-2011/96, was distributed to program participants on April 8, 2011. As reported previously, the final Quarterly for FY 2010, Deep Burn Program Quarterly Report for July - September 2010, ORNL/TM-2010/301, was announced to program participants and posted to the website on December 28, 2010. This report discusses the following: (1) Thermochemical Data and Model Development - (a) Thermochemical Modeling, (b) Thermomechanical Behavior, (c) Actinide and Fission Product Transport, (d) Radiation Damage and Properties; (2) TRU (transuranic elements) TRISO (tri-structural isotropic) Development - (a) TRU Kernel Development, (b) Coating Development; (3) Advanced TRISO Applications - Metal Matrix Fuels for LWR; (4) LWR Fully Ceramic Fuel - (a) FCM Fabrication Development, (b) FCM Irradiation Testing; (5) Fuel Performance and Analytical Analysis - Fuel Performance Modeling; and (6) ZrC Properties and Handbook - Properties of ZrC.

  19. Automatic Characterization of Cross-section Coated Particle Nuclear Fuel using Greedy Coupled Bayesian Snakes

    SciTech Connect

    Price, Jeffery R; Aykac, Deniz; Hunn, John D; Kercher, Andrew K

    2007-01-01

    We describe new image analysis developments in support of the U.S. Department of Energy's (DOE) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program. We previously reported a non-iterative, Bayesian approach for locating the boundaries of different particle layers in cross-sectional imagery. That method, however, had to be initialized by manual preprocessing where a user must select two points in each image, one indicating the particle center and the other indicating the first layer interface. Here, we describe a technique designed to eliminate the manual preprocessing and provide full automation. With a low resolution image, we use 'EdgeFlow' to approximate the layer boundaries with circular templates. Multiple snakes are initialized to these circles and deformed using a greedy Bayesian strategy that incorporates coupling terms as well as a priori information on the layer thicknesses and relative contrast. We show results indicating the effectiveness of the proposed method.

  20. Coated powder for electrolyte matrix for carbonate fuel cell

    DOEpatents

    Iacovangelo, Charles D.; Browall, Kenneth W.

    1985-01-01

    A plurality of electrolyte carbonate-coated ceramic particle which does not differ significantly in size from that of the ceramic particle and wherein no significant portion of the ceramic particle is exposed is fabricated into a porous tape comprised of said coated-ceramic particles bonded together by the coating for use in a molten carbonate fuel cell.

  1. Preparation of UC0.07-0.10N0.90-0.93 spheres for TRISO coated fuel particles

    NASA Astrophysics Data System (ADS)

    Hunt, R. D.; Silva, C. M.; Lindemer, T. B.; Johnson, J. A.; Collins, J. L.

    2014-05-01

    The US Department of Energy is considering a new nuclear fuel that would be less susceptible to ruptures during a loss-of-coolant accident. The fuel would consist of tristructural isotropic coated particles with dense uranium nitride (UN) kernels with diameters of 650 or 800 μm. The objectives of this effort are to make uranium oxide microspheres with adequately dispersed carbon nanoparticles and to convert these microspheres into UN spheres, which could be then sintered into kernels. Recent improvements to the internal gelation process were successfully applied to the production of uranium gel spheres with different concentrations of carbon black. After the spheres were washed and dried, a simple two-step heat profile was used to produce porous microspheres with a chemical composition of UC0.07-0.10N0.90-0.93. The first step involved heating the microspheres to 2023 K in a vacuum, and in the second step, the microspheres were held at 1873 K for 6 h in flowing nitrogen.

  2. Particle fuel diversion structure

    SciTech Connect

    Eshleman, R. D.

    1985-07-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for after-burning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart vertically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in spaced relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  3. Performance of glucose/O2 enzymatic fuel cell based on supporting electrodes over-coated by polymer-nanogold particle composite with entrapped enzymes

    NASA Astrophysics Data System (ADS)

    Huo, W. S.; Zeng, H.; Yang, Y.; Zhang, Y. H.

    2017-03-01

    Enzymatic electrodes over-coated by thin film of nano-composite made up of polymer and functionalized nano-gold particle was prepared. Glucose/O2 membrane-free enzymatic fuel cell based on nano-composite based electrodes with incorporated glucose oxidase and laccase was assembled. This enzymatic fuel cell exhibited high energy out-put density even when applied in human serum. Catalytic cycle involved in enzymatic fuel cell was limited by oxidation of glucose occurred on bioanode resulting from impact of sophisticated interaction between active site in glucose oxidase and nano-gold particle on configuration of redox center of enzyme molecule which crippled catalytic efficiency of redox protein.

  4. Multidimensional Multiphysics Simulation of TRISO Particle Fuel

    SciTech Connect

    J. D. Hales; R. L. Williamson; S. R. Novascone; D. M. Perez; B. W. Spencer; G. Pastore

    2013-11-01

    Multidimensional multiphysics analysis of TRISO-coated particle fuel using the BISON finite-element based nuclear fuels code is described. The governing equations and material models applicable to particle fuel and implemented in BISON are outlined. Code verification based on a recent IAEA benchmarking exercise is described, and excellant comparisons are reported. Multiple TRISO-coated particles of increasing geometric complexity are considered. It is shown that the code's ability to perform large-scale parallel computations permits application to complex 3D phenomena while very efficient solutions for either 1D spherically symmetric or 2D axisymmetric geometries are straightforward. Additionally, the flexibility to easily include new physical and material models and uncomplicated ability to couple to lower length scale simulations makes BISON a powerful tool for simulation of coated-particle fuel. Future code development activities and potential applications are identified.

  5. Multidimensional multiphysics simulation of TRISO particle fuel

    NASA Astrophysics Data System (ADS)

    Hales, J. D.; Williamson, R. L.; Novascone, S. R.; Perez, D. M.; Spencer, B. W.; Pastore, G.

    2013-11-01

    Multidimensional multiphysics analysis of TRISO-coated particle fuel using the BISON finite element nuclear fuels code is described. The governing equations and material models applicable to particle fuel and implemented in BISON are outlined. Code verification based on a recent IAEA benchmarking exercise is described, and excellent comparisons are reported. Multiple TRISO-coated particles of increasing geometric complexity are considered. The code's ability to use the same algorithms and models to solve problems of varying dimensionality from 1D through 3D is demonstrated. The code provides rapid solutions of 1D spherically symmetric and 2D axially symmetric models, and its scalable parallel processing capability allows for solutions of large, complex 3D models. Additionally, the flexibility to easily include new physical and material models and straightforward ability to couple to lower length scale simulations makes BISON a powerful tool for simulation of coated-particle fuel. Future code development activities and potential applications are identified.

  6. Considerations of the Effects of Partial Debonding of the IPyC and Particle Asphericity on TRISCO-coated Fuel Behavior

    SciTech Connect

    G. K. Miller; D. A. Petti; J. T. Maki

    2004-09-01

    The fundamental design for a gas-cooled reactor relies on the behavior of the coated particle fuel. The coating layers surrounding the fuel kernels in these spherical particles, consisting of pyrolytic carbon and silicon carbide layers, act as a pressure vessel that retains fission product gases. Many more fuel particles have failed in US irradiations than would be expected when only one-dimensional pressure vessel failures are considered. Post-irradiation examinations indicate that multi-dimensional effects may have contributed to these failures, such as (1) irradiation-induced shrinkage cracks in the inner pyrocarbon (IPyC) layer, (2) partial debonding between the IPyC and SiC layers, and (3) deviations from a perfectly spherical shape. An approach that was used previously to evaluate the effects of irradiation-induced shrinkage cracks is used herein to assess the effects of partial debonding and asphericity. Results of this investigation serve to identify circumstances where these mechanisms may contribute to particle failures.

  7. Evolution of Particle Bed Reactor Fuel

    NASA Astrophysics Data System (ADS)

    Jensen, Russell R.; Evans, Robert S.; Husser, Dewayne L.; Kerr, John M.

    1994-07-01

    To realize the potential performance advantages inherent in a particle bed reactor (PBR) for nuclear thermal propulsion (NTP) applications, high performance particle fuel is required. This fuel must operate safely and without failure at high temperature in high pressure, flowing hydrogen propellant. The mixed mean outlet temperature of the propellant is an important characteristic of PBR performance. This temperature is also a critical parameter for fuel particle design because it dictates the required maximum fuel operating temperature. In this paper, the evolution in PBR fuel form to achieve higher operating temperatures is discussed and the potential thermal performance of the different fuel types is evaluated. It is shown that the optimum fuel type for operation under the demanding conditions in a PBR is a coated, solid carbide particle.

  8. Evaluation of Alternate Materials for Coated Particle Fuels for the Gas-Cooled Fast Reactor. Laboratory Directed Research and Development Program FY 2006 Final Report

    SciTech Connect

    Paul A. Demkowicz; Karen Wright; Jian Gan; David Petti; Todd Allen; Jake Blanchard

    2006-09-01

    Candidate ceramic materials were studied to determine their suitability as Gas-Cooled Fast Reactor particle fuel coatings. The ceramics examined in this work were: TiC, TiN, ZrC, ZrN, AlN, and SiC. The studies focused on (i) chemical reactivity of the ceramics with fission products palladium and rhodium, (ii) the thermomechanical stresses that develop in the fuel coatings from a variety of causes during burnup, and (iii) the radiation resiliency of the materials. The chemical reactivity of TiC, TiN, ZrC, and ZrN with Pd and Rh were all found to be much lower than that of SiC. A number of important chemical behaviors were observed at the ceramic-metal interfaces, including the formation of specific intermetallic phases and a variation in reaction rates for the different ceramics investigated. Based on the data collected in this work, the nitride ceramics (TiN and ZrN) exhibit chemical behavior that is characterized by lower reaction rates with Pd and Rh than the carbides TiC and ZrC. The thermomechanical stresses in spherical fuel particle ceramic coatings were modeled using finite element analysis, and included contributions from differential thermal expansion, fission gas pressure, fuel kernel swelling, and thermal creep. In general the tangential stresses in the coatings during full reactor operation are tensile, with ZrC showing the lowest values among TiC, ZrC, and SiC (TiN and ZrN were excluded from the comprehensive calculations due to a lack of available materials data). The work has highlighted the fact that thermal creep plays a critical role in the development of the stress state of the coatings by relaxing many of the stresses at high temperatures. To perform ion irradiations of sample materials, an irradiation beamline and high-temperature sample irradiation stage was constructed at the University of Wisconsin’s 1.7MV Tandem Accelerator Facility. This facility is now capable of irradiating of materials to high dose while controlling sample temperature

  9. Coated particle waste form development

    SciTech Connect

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  10. Particle fuel delivery control device

    SciTech Connect

    Eshleman, R. D.

    1985-04-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for afterburning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart verrtically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in space relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling rhoguh the passageways and particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  11. Modeling Deep Burn TRISO particle nuclear fuel

    NASA Astrophysics Data System (ADS)

    Besmann, T. M.; Stoller, R. E.; Samolyuk, G.; Schuck, P. C.; Golubov, S. I.; Rudin, S. P.; Wills, J. M.; Coe, J. D.; Wirth, B. D.; Kim, S.; Morgan, D. D.; Szlufarska, I.

    2012-11-01

    Under the DOE Deep Burn program TRISO fuel is being investigated as a fuel form for consuming plutonium and minor actinides, and for greater efficiency in uranium utilization. The result will thus be to drive TRISO particulate fuel to very high burn-ups. In the current effort the various phenomena in the TRISO particle are being modeled using a variety of techniques. The chemical behavior is being treated utilizing thermochemical analysis to identify phase formation/transformation and chemical activities in the particle, including kernel migration. Density functional theory is being used to understand fission product diffusion within the plutonia oxide kernel, the fission product's attack on the SiC coating layer, as well as fission product diffusion through an alternative coating layer, ZrC. Finally, a multiscale approach is being used to understand thermal transport, including the effect of radiation damage induced defects, in a model SiC material.

  12. Defect fractions for fissile and fertile TRISO-coated fuel

    SciTech Connect

    Adams, C.C.

    1986-09-01

    High quality TRISCO-coated UCO and ThO{sub 2} particles with reference MHTGR dimensions were produced in a coating campaign in August and September 1986 for irradiation tests. The heavy metal contamination and the defect levels were below the limits established for the MHTGR fuel. Over 9 kg of uranium in UCO and 30 kg of thorium in ThO{sub 2} were TRISCO-coated in 4 fissile and 3 fertile batches in the 240mm Development Coater. These coated fuel particles will be used to produce fuel rods for testing in the irradiation validation tests to be conducted in capsules HRB-19, -20 and -21 on the DOE Fuel and Fission Product Technology Program. 3 refs., 6 figs., 6 tabs.

  13. Nuclear fuel particles and method of making nuclear fuel compacts therefrom

    DOEpatents

    DeVelasco, Rubin I.; Adams, Charles C.

    1991-01-01

    Methods for making nuclear fuel compacts exhibiting low heavy metal contamination and fewer defective coatings following compact fabrication from a mixture of hardenable binder, such as petroleum pitch, and nuclear fuel particles having multiple layer fission-product-retentive coatings, with the dense outermost layer of the fission-product-retentive coating being surrounded by a protective overcoating, e.g., pyrocarbon having a density between about 1 and 1.3 g/cm.sup.3. Such particles can be pre-compacted in molds under relatively high pressures and then combined with a fluid binder which is ultimately carbonized to produce carbonaceous nuclear fuel compacts having relatively high fuel loadings.

  14. Coating parameters of zirconium carbide on advanced TRISO fuels

    NASA Astrophysics Data System (ADS)

    Dulude, Michael C.

    The feasibility of using very high temperature reactors (VHTR) as part of the next generation of nuclear reactors greatly depends on the tri-structural isotropic (TRISO) fuel particles reliability to retain both gaseous and metallic fission products created in irradiated UO2. Most research devoted to TRISO fuel particles has focused on the characteristics and retention ability of silicon carbide as the main barrier against metallic fission products. This work investigates the deposition parameters necessary to create advanced TRISO particles consisting of the standard SiC TRISO coatings with an additional layer of ZrC applied directly to the UO2 fuel kernel. The additional ZrC layer will act as an oxygen getter to prevent failure mechanisms experienced in TRISO particles. Two failure mechanisms that are of the most concern are the over pressurization of the particles and kernel migration within the TRISO particles. In this study successful ZrC coatings were created and the deposition characteristics were analyzed via optical and SEM microscopy techniques. The ZrC layer was confirmed through XRD analysis. This investigation also reduced U3O8 microspheres to UO2 in an argon atmosphere. The oxygen to metal ratio from the reduced U3O8 was back calculated from oxidation analysis performed with a TGA machine. Once consistent repeatability is shown with coating surrogate zirconia kernels, advanced TRISO coatings will be deposited on the UO2 fuel kernels.

  15. Fracture strength and principal stress fields during crush testing of the SiC layer in TRISO-coated fuel particles

    NASA Astrophysics Data System (ADS)

    Davis, Brian C.; Ward, Logan; Butt, Darryl P.; Fillery, Brent; Reimanis, Ivar

    2016-08-01

    Diametrical compression testing is an important technique to evaluate fracture properties of the SiC layer in TRISO-coated nuclear fuel particles. This study was conducted to expand the understanding and improve the methodology of the test. An analytic solution and multiple FEA models are used to determine the development of the principal stress fields in the SiC shell during a crush test. An ideal fracture condition where the diametrical compression test best mimics in-service internal pressurization conditions was discovered. For a small set of empirical data points, results from different analysis methodologies were input to an iterative Weibull equation set to determine characteristic strength (332.9 MPa) and Weibull modulus (3.80). These results correlate well with published research. It is shown that SiC shell asphericity is currently the limiting factor of greatest concern to obtaining repeatable results. Improvements to the FEA are the only apparent method for incorporating asphericity and improving accuracy.

  16. Coated U(Mo) Fuel: As-Fabricated Microstructures

    SciTech Connect

    Emmanuel Perez; Dennis D. Keiser, Jr.; Ann Leenaers; Sven Van den Berghe; Tom Wiencek

    2014-04-01

    As part of the development of low-enriched uranium fuels, fuel plates have recently been tested in the BR-2 reactor as part of the SELENIUM experiment. These fuel plates contained fuel particles with either Si or ZrN thin film coating (up to 1 µm thickness) around the U-7Mo fuel particles. In order to best understand irradiation performance, it is important to determine the starting microstructure that can be observed in as-fabricated fuel plates. To this end, detailed microstructural characterization was performed on ZrN and Si-coated U-7Mo powder in samples taken from AA6061-clad fuel plates fabricated at 500°C. Of interest was the condition of the thin film coatings after fabrication at a relatively high temperature. Both scanning electron microscopy and transmission electron microscopy were employed. The ZrN thin film coating was observed to consist of columns comprised of very fine ZrN grains. Relatively large amounts of porosity could be found in some areas of the thin film, along with an enrichment of oxygen around each of the the ZrN columns. In the case of the pure Si thin film coating sample, a (U,Mo,Al,Si) interaction layer was observed around the U-7Mo particles. Apparently, the Si reacted with the U-7Mo and Al matrix during fuel plate fabrication at 500°C to form this layer. The microstructure of the formed layer is very similar to those that form in U-7Mo versus Al-Si alloy diffusion couples annealed at higher temperatures and as-fabricated U-7Mo dispersion fuel plates with Al-Si alloy matrix fabricated at 500°C.

  17. Method of identifying defective particle coatings

    DOEpatents

    Cohen, Mark E.; Whiting, Carlton D.

    1986-01-01

    A method for identifying coated particles having defective coatings desig to retain therewithin a build-up of gaseous materials including: (a) Pulling a vacuum on the particles; (b) Backfilling the particles at atmospheric pressure with a liquid capable of wetting the exterior surface of the coated particles, said liquid being a compound which includes an element having an atomic number higher than the highest atomic number of any element in the composition which forms the exterior surface of the particle coating; (c) Drying the particles; and (d) Radiographing the particles. By television monitoring, examination of the radiographs is substantially enhanced.

  18. Particle adhesion in powder coating

    SciTech Connect

    Mazumder, M.K.; Wankum, D.L.; Knutson, M.; Williams, S.; Banerjee, S.

    1996-12-31

    Electrostatic powder coating is a widely used industrial painting process. It has three major advantages: (1) it provides high quality durable finish, (2) the process is environmentally friendly and does not require the use of organic solvents, and (3) it is economically competitive. The adhesion of electrostatically deposited polymer paint particles on the grounded conducting substrate depends upon many parameters: (a) particle size and shape distributions, (b) electrostatic charge distributions, (c) electrical resistivity, (d) dielectric strength of the particles, (e) thickness of the powder film, (f) presence and severity of the back corona, and (g) the conductivity and surface properties of the substrate. The authors present a model on the forces of deposition and adhesion of corona charged particles on conducting substrates.

  19. Advanced Fuels Campaign Cladding & Coatings Meeting Summary

    SciTech Connect

    Not Listed

    2013-03-01

    The Fuel Cycle Research and Development (FCRD) Advanced Fuels Campaign (AFC) organized a Cladding and Coatings operational meeting February 12-13, 2013, at Oak Ridge National Laboratory (ORNL). Representatives from the U.S. Department of Energy (DOE), national laboratories, industry, and universities attended the two-day meeting. The purpose of the meeting was to discuss advanced cladding and cladding coating research and development (R&D); review experimental testing capabilities for assessing accident tolerant fuels; and review industry/university plans and experience in light water reactor (LWR) cladding and coating R&D.

  20. Coated particles for lithium battery cathodes

    DOEpatents

    Singh, Mohit; Eitouni, Hany Basam; Pratt, Russell Clayton; Mullin, Scott Allen; Wang, Xiao-Liang

    2017-07-18

    Particles of cathodic materials are coated with polymer to prevent direct contact between the particles and the surrounding electrolyte. The polymers are held in place either by a) growing the polymers from initiators covalently bound to the particle, b) attachment of the already-formed polymers by covalently linking to functional groups attached to the particle, or c) electrostatic interactions resulting from incorporation of cationic or anionic groups in the polymer chain. Carbon or ceramic coatings may first be formed on the surfaces of the particles before the particles are coated with polymer. The polymer coating is both electronically and ionically conductive.

  1. Pyrolytic carbon-coated nuclear fuel

    DOEpatents

    Lindemer, Terrence B.; Long, Jr., Ernest L.; Beatty, Ronald L.

    1978-01-01

    An improved nuclear fuel kernel having at least one pyrolytic carbon coating and a silicon carbon layer is provided in which extensive interaction of fission product lanthanides with the silicon carbon layer is avoided by providing sufficient UO.sub.2 to maintain the lanthanides as oxides during in-reactor use of said fuel.

  2. Methylecgonidine coats the crack particle.

    PubMed

    Wood, R W; Shojaie, J; Fang, C P; Graefe, J F

    1996-01-01

    Crack is a form of cocaine base self-administered by smoking. When heated, it volatilizes and may partially pyrolyze to methylecgonidine (MEG). Upon cooling, a condensation aerosol forms. Heating cocaine base in model crack pipes produced particles of about 1 micron in diameter, regardless of the amount heated; however, MEG concentration increased from < or = 2% at 10 mg per heating to as much as 5% at 30 mg per heating. Methylecgonidine was < or = 1% of the recovered material when cocaine was vaporized off a heated wire coil, but the particles were larger (2-5 microns), and the distribution disperse. The vapor pressure of MEG was higher [log P(mm Hg) = 9.994 - 3530/T] than cocaine base, consistent with MEG coating the droplet during condensation, and with evaporation during aging or dilution. Disappearance of MEG from a chamber filled with crack smoke was a two-component process, one proceeding at the rate of cocaine particle removal, and the other at the desorption rate from other surfaces. Particle diameter influences the deposition site in the respiratory tract; thus, the likely different patterns of deposition in the respiratory tract of humans and animals of crack aerosols produced by different techniques warrant consideration, as they may influence our understanding of immediate and delayed sequelae of the inhalation of cocaine and its pyrolysis product, MEG.

  3. On-Line Nondestructive Methods for Examining Fuel Particles

    SciTech Connect

    Pardini, Allan F.; Bond, Leonard J.; Good, Morris S.; Bunch, Kyle J.; Sandness, Gerald A.; Hockey, Ronald L.; Saurwein, John J.; Gray, Joseph N.

    2007-09-15

    Tri-isotropic (TRISO) particle fuels, being considered for use in various advanced nuclear power reactors, consist of sub-millimeter diameter uranium oxide spheres uniformly coated to prevent the release of fission products into the reactor. About 15 billion of these spheres are needed to fuel a single reactor. Current quality control (QC) methods are manual, can destroy test specimens, and are not economically feasible. Replacing these methods with nondestructive evaluation (NDE) techniques, automated for higher speed, will make fuel production and reactor operation economically feasible, considering the requirement for extremely large fuel particle throughput rates. This paper reports a project to develop and demonstrate nondestructive examination methods to detect and reject defective particles, and in particular progress made in the final year of a Nuclear Energy Research Initiative (NERI) project . The work explored adapting, developing, and demonstrating innovative nondestructive test methods to cost-effectively assure the quality of large percentages of the fuel particles.

  4. Method for fluidizing and coating ultrafine particles, device for fluidizing and coating ultrafine particles

    DOEpatents

    Li, Jie; Liu, Yung Y

    2015-01-20

    The invention provides a method for dispersing particles within a reaction field, the method comprising confining the particles to the reaction field using a standing wave. The invention also provides a system for coating particles, the system comprising a reaction zone; a means for producing fluidized particles within the reaction zone; a fluid to produce a standing wave within the reaction zone; and a means for introducing coating moieties to the reaction zone. The invention also provides a method for coating particles, the method comprising fluidizing the particles, subjecting the particles to a standing wave; and contacting the subjected particles with a coating moiety.

  5. Laser ultrasonics evaluation and testing of coated HTR nuclear fuel

    NASA Astrophysics Data System (ADS)

    Amziane, Ahmed; Amari, Mohamed; Mounier, Denis; Breteau, Jean-Marc; Joly, Nicolas; Edely, Mathieu; Larcher, Maxime; Noiré, Paul; Banchet, Julien; Tisseur, David; Gusev, Vitalyi

    2011-05-01

    Laser ultrasonics was applied to the manufacturing control of the quality and integrity (no failure) of coated spherical particles designed for High Temperature Reactors (HTR). The coating of the nuclear fuel kernel is designed to prevent from the diffusion of fission products outside the particle during reactor operation. The quality assessment of the coating layers is of major importance. Using laser ultrasonics, we determined the vibration eigenmodes of dummy HTR particles. The vibration spectrum of a HTR particle provides a non-destructive method of evaluating some important mechanical parameters of the coating. Moreover, without damaging the particle, the laser ultrasonics technique allows to test the presence of a crack in the SiC layer, through the observation of the particle vibration spectrum, which is significantly changed, compared to that of a defect-free particle. We applied nanosecond acoustic pulses, i.e., high frequency laser-generated ultrasound, to measure the acoustic velocity of longitudinal waves the SiC layer. This technique provides an alternative method of evaluation of the Young modulus of the SiC layer. We measure the velocity of surface acoustic waves (SAW) on a pyrocarbon layer cross-section and we demonstrated that the anisotropy of the internal pyrocarbon layer can be evaluated by laser ultrasonics.

  6. EBSD investigation of SiC for HTR fuel particles

    NASA Astrophysics Data System (ADS)

    Helary, D.; Dugne, O.; Bourrat, X.; Jouneau, P. H.; Cellier, F.

    2006-05-01

    Electron back-scattering diffraction (EBSD) can be successfully performed on SiC coatings for HTR fuel particles. EBSD grain maps obtained from thick and thin unirradiated samples are presented, along with pole figures showing textures and a chart showing the distribution of grain aspect ratios. This information is of great interest, and contributes to improving the process parameters and ensuring the reproducibility of coatings.

  7. Metallic impurities-silicon carbide interaction in HTGR fuel particles

    NASA Astrophysics Data System (ADS)

    Minato, Kazuo; Ogawa, Toru; Kashimura, Satoru; Fukuda, Kousaku; Shimizu, Michio; Tayama, Yoshinobu; Takahashi, Ishio

    1990-12-01

    Corrosion of the coating layers of silicon carbide (SiC) by metallic impurities was observed in irradiated Triso-coated uranium dioxide particles for high temperature gas-cooled reactors with an optical microscope and an electron probe micro-analyzer. The SiC layers were attacked from the outside of the particles. The main element observed in the corroded areas was iron, but sometimes iron and nickel were found. These elements must have been contained as impurities in the graphite matrix in which the coated particles were dispersed. Since these elements are more stable thermodynamically in the presence of SiC than in the presence of graphite at irradiation temperatures, they were transferred to the SiC layer to form more stable silicides. During fuel manufacturing processes, intensive care should be taken to prevent the fuel from being contaminated with those elements which react with SiC.

  8. The measurement of silver diffusivity in zirconium carbide to study the release behavior of 110mAg in the ZrC TRISO-coated nuclear fuel particle

    NASA Astrophysics Data System (ADS)

    Yang, Young-Ki; Allen, Todd R.

    2016-03-01

    The tri-structural isotropic (TRISO) coated particle fuel has been developed and used for high temperature gas-cooled reactors (HTGRs). It provides a unique robustness of the first barrier for the fission products. The TRISO fuel particle has typically consisted of a UO2 or UCO kernel, surrounded by successive layers of porous carbon, dense inner pyrocarbon, silicon carbide, and dense outer pyrocarbon. During operation, however, the SiC layer has been known to release radioactive silver 110mAg which makes maintenance more difficult and thus costly. Zirconium carbide has been considered as a promising alternative to the SiC fission product barrier. ZrC exhibits high temperature stability and possibly possesses superior Pd resistance, while the retention properties especially for silver have not been adequately studied. To help elucidate the diffusive behavior of silver in the ZrC coating of the TRISO-coated particle, a new diffusion experimental technique, called the encapsulating source method, has been developed by constructing a constant source diffusion couple between ZrC and Ag gas originated from Zr-Ag solid solution. Scanning electron microscopy (SEM), wavelength-dispersive X-ray spectroscopy (WDS), electron backscatter diffraction (EBSD) and optical methods were used to analyze the diffusion couple annealed at 1500 °C. The resultant diffusion coefficient of Ag in single-crystalline ZrC0.84 at 1500 °C was experimentally determined to be about 2.8 (±1.2) × 10-17 m2/s.

  9. Carbon fuel particles used in direct carbon conversion fuel cells

    DOEpatents

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  10. Carbon fuel particles used in direct carbon conversion fuel cells

    DOEpatents

    Cooper, John F [Oakland, CA; Cherepy, Nerine [Oakland, CA

    2012-01-24

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  11. Carbon fuel particles used in direct carbon conversion fuel cells

    DOEpatents

    Cooper, John F [Oakland, CA; Cherepy, Nerine [Oakland, CA

    2011-08-16

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  12. Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

    DOEpatents

    Cooper, John F.; Cherepy, Nerine

    2008-10-21

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  13. Hollow sphere ceramic particles for abradable coatings

    SciTech Connect

    Longo, F.N.; Bader, N.F. III; Dorfman, M.R.

    1984-05-22

    A hollow sphere ceramic flame spray powder is disclosed. The desired constituents are first formed into agglomerated particles in a spray drier. Then the agglomerated particles are introduced into a plasma flame which is adjusted so that the particles collected are substantially hollow. The hollow sphere ceramic particles are suitable for flame spraying a porous and abradable coating. The hollow particles may be selected from the group consisting of zirconium oxide and magnesium zirconate.

  14. Acoustofluidic coating of particles and cells.

    PubMed

    Ayan, Bugra; Ozcelik, Adem; Bachman, Hunter; Tang, Shi-Yang; Xie, Yuliang; Wu, Mengxi; Li, Peng; Huang, Tony Jun

    2016-11-01

    On-chip microparticle and cell coating technologies enable a myriad of applications in chemistry, engineering, and medicine. Current microfluidic coating technologies often rely on magnetic labeling and concurrent deflection of particles across laminar streams of chemicals. Herein, we introduce an acoustofluidic approach for microparticle and cell coating by implementing tilted-angle standing surface acoustic waves (taSSAWs) into microchannels with multiple inlets. The primary acoustic radiation force generated by the taSSAW field was exploited in order to migrate the particles across the microchannel through multiple laminar streams, which contained the buffer and coating chemicals. We demonstrate effective coating of polystyrene microparticles and HeLa cells without the need for magnetic labelling. We characterized the coated particles and HeLa cells with fluorescence microscopy and scanning electron microscopy. Our acoustofluidic-based particle and cell coating method is label-free, biocompatible, and simple. It can be useful in the on-chip manufacturing of many functional particles and cells.

  15. Article coated with flash bonded superhydrophobic particles

    DOEpatents

    Simpson, John T [Clinton, TN; Blue, Craig A [Knoxville, TN; Kiggans, Jr., James O [Oak Ridge, TN

    2010-07-13

    A method of making article having a superhydrophobic surface includes: providing a solid body defining at least one surface; applying to the surface a plurality of diatomaceous earth particles and/or particles characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m, the particles being further characterized by a plurality of nanopores, wherein at least some of the nanopores provide flow through porosity, the particles being further characterized by a plurality of spaced apart nanostructured features that include a contiguous, protrusive material; flash bonding the particles to the surface so that the particles are adherently bonded to the surface; and applying a hydrophobic coating layer to the surface and the particles so that the hydrophobic coating layer conforms to the nanostructured features.

  16. Microfluidic Controlled Conformal Coating of Particles

    NASA Astrophysics Data System (ADS)

    Tsai, Scott; Wexler, Jason; Wan, Jiandi; Stone, Howard

    2011-11-01

    Coating flows are an important class of fluid mechanics problems. Typically a substrate is coated with a moving continuous film, but it is also possible to consider coating of discrete objects. In particular, in applications involving coating of particles that are useful in drug delivery, the coatings act as drug-carrying vehicles, while in cell therapy a thin polymeric coating is required to protect the cells from the host's immune system. Although many functional capabilities have been developed for lab-on-a-chip devices, a technique for coating has not been demonstrated. We present a microfluidic platform developed to coat micron-size spheres with a thin aqueous layer by magnetically pulling the particles from the aqueous phase to the non-aqueous phase in a co-flow. Coating thickness can be adjusted by the average fluid speed and the number of beads encapsulated inside a single coat is tuned by the ratio of magnetic to interfacial forces acting on the beads.

  17. Assessment of ceramic coatings for metal fuel melting crucible

    SciTech Connect

    Kim, Ki-Hwan; Song, Hoon; Kim, Jong-Hwan; Oh, Seok-Jin; Kim, Hyung-Tae; Lee, Chan-Bock

    2013-07-01

    The objective of this study is to develop a coating method and material for crucibles to prevent material interactions with the U-Zr/U-TRU-Zr fuels during the manufacturing of SFR fuels. Refractory coatings were applied to niobium substrates by vacuum plasma-spray coating method. Melt dipping tests conducted were the coated rods lowered into the fuel melt at 1600 C. degrees, and withdrawn and cooled outside the crucible in the inert atmosphere of the induction furnace. Melt dipping tests of the coated Nb rods indicated that plasma-sprayed Y{sub 2}O{sub 3} coating doesn't form significant reaction layer between fuel melt and coating layer. Melt dipping tests of the coated Nb rods showed that TiC, TaC, and Y{sub 2}O{sub 3} coatings exhibited the promising performance among other ceramic coatings. These materials could be promising candidate materials for the reusable melt crucible of metal fuel for SFR. In addition, in order to develop the vacuum plasma-spray coating method for re-usable crucible of metal fuel slugs to be overcome the issue of thermal expansion mismatch between coating material and crucible, various combinations of coating conditions were investigated to find the bonding effect on the substrate in pursuit of more effective ways to withstand the thermal stresses. It is observed that most coating methods maintained sound coating state in U-Zr melt. (authors)

  18. Behavior of magnetorheological elastomers with coated particles

    NASA Astrophysics Data System (ADS)

    Behrooz, Majid; Sutrisno, Joko; Zhang, Lingyue; Fuchs, Alan; Gordaninejad, Faramarz

    2015-03-01

    Iron particle coating can improve the behavior of magnetorheological elastomers (MREs) by inhibiting iron particle rusting; however, such a process can change physical properties of MREs such as oxidation resistance, shear modulus, and stiffness change due to an applied magnetic field. In this study, MRE samples are fabricated with regular and polymerized iron particles. To investigate the possibility and extent of these changes, polymerized particle MRE samples are made using a combination of reversible addition fragmentation chain transfer and click chemistry. Shear test sample MREs with pure elastomer and 50 wt% MRE with and without polymerization are fabricated. To observe the effect of oxidation on shear properties of MREs, pure elastomer and 50 wt% coated and non-coated samples are oxidized using accelerated oxidation procedure. Experimental results show that oxidation significantly reduces the shear modulus of the elastomer matrix. The coating process of iron particles does not significantly change the shear modulus of resulting MREs but reduces the loss of shear modulus due to oxidation.

  19. Nuclear Rocket Ceramic Metal Fuel Fabrication Using Tungsten Powder Coating and Spark Plasma Sintering

    NASA Technical Reports Server (NTRS)

    Barnes, M. W.; Tucker, D. S.; Hone, L.; Cook, S.

    2017-01-01

    Nuclear thermal propulsion is an enabling technology for crewed Mars missions. An investigation was conducted to evaluate spark plasma sintering (SPS) as a method to produce tungsten-depleted uranium dioxide (W-dUO2) fuel material when employing fuel particles that were tungsten powder coated. Ceramic metal fuel wafers were produced from a blend of W-60vol% dUO2 powder that was sintered via SPS. The maximum sintering temperatures were varied from 1,600 to 1,850 C while applying a 50-MPa axial load. Wafers exhibited high density (>95% of theoretical) and a uniform microstructure (fuel particles uniformly dispersed throughout tungsten matrix).

  20. Composite of coated magnetic alloy particle

    DOEpatents

    Moorhead, Arthur J.; Kim, Hyoun-Ee

    2000-01-01

    A composite structure and method for manufacturing same, the composite structure being comprised of metal particles and an inorganic bonding media. The method comprises the steps of coating particles of a metal powder with a thin layer of an inorganic bonding media selected from the group of powders consisting of a ceramic, glass, and glass-ceramic. The particles are assembled in a cavity and heat, with or without the addition of pressure, is thereafter applied to the particles until the layer of inorganic bonding media forms a strong bond with the particles and with the layer of inorganic bonding media on adjacent particles. The resulting composite structure is strong and remains cohesive at high temperatures.

  1. Design of an Online Fission Gas Monitoring System for Post-irradiation Examination Heating Tests of Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    SciTech Connect

    Dawn Scates

    2010-10-01

    A new Fission Gas Monitoring System (FGMS) has been designed at the Idaho National Laboratory (INL) for use of monitoring online fission gas-released during fuel heating tests. The FGMS will be used with the Fuel Accident Condition Simulator (FACS) at the Hot Fuels Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) within the INL campus. Preselected Advanced Gas Reactor (AGR) TRISO (Tri-isotropic) fuel compacts will undergo testing to assess the fission product retention characteristics under high temperature accident conditions. The FACS furnace will heat the fuel to temperatures up to 2,000ºC in a helium atmosphere. Released fission products such as Kr and Xe isotopes will be transported downstream to the FGMS where they will accumulate in cryogenically cooledcollection traps and monitored with High Purity Germanium (HPGe) detectors during the heating process. Special INL developed software will be used to monitor the accumulated fission products and will report data in near real-time. These data will then be reported in a form that can be readily available to the INL reporting database. This paper describes the details of the FGMS design, the control and acqusition software, system calibration, and the expected performance of the FGMS. Preliminary online data may be available for presentation at the High Temperature Reactor (HTR) conference.

  2. Method for applying pyrolytic carbon coatings to small particles

    DOEpatents

    Beatty, Ronald L.; Kiplinger, Dale V.; Chilcoat, Bill R.

    1977-01-01

    A method for coating small diameter, low density particles with pyrolytic carbon is provided by fluidizing a bed of particles wherein at least 50 per cent of the particles have a density and diameter of at least two times the remainder of the particles and thereafter recovering the small diameter and coated particles.

  3. Molecular Level Coating of Metal Oxide Particles

    NASA Technical Reports Server (NTRS)

    McDaniel, Patricia R. (Inventor); St.Clair, Terry L. (Inventor)

    2002-01-01

    Polymer encapsulated metal oxide particles are prepared by combining a polyamide acid in a polar osmotic solvent with a metal alkoxide solution. The polymer was imidized and the metal oxide formed simultaneously in a refluxing organic solvent. The resulting polymer-metal oxide is an intimately mixed commingled blend, possessing, synergistic properties of both the polymer and preceramic metal oxide. The encapsulated metal oxide particles have multiple uses including, being useful in the production of skin lubricating creams, weather resistant paints, as a filler for paper. making ultraviolet light stable filled printing ink, being extruded into fibers or ribbons, and coatings for fibers used in the production of composite structural panels.

  4. Molecular Level Coating for Metal Oxide Particles

    NASA Technical Reports Server (NTRS)

    McDaniel, Patricia R. (Inventor); Saint Clair, Terry L. (Inventor)

    2000-01-01

    Polymer encapsulated metal oxide particles are prepared by combining a polyamide acid in a polar aprotic solvent with a metal alkoxide solution. The polymer was imidized and the metal oxide formed simultaneously in a refluxing organic solvent. The resulting polymer-metal oxide is an intimately mixed commingled blend, possessing synergistic properties of both the polymer and preceramic metal oxide. The encapsulated metal oxide particles have multiple uses including, being useful in the production of skin lubricating creams, weather resistant paints, as a filler for paper, making ultraviolet light stable filled printing ink, being extruded into fibers or ribbons, and coatings for fibers used in the production of composite structural panels.

  5. Molecular Level Coating of Metal Oxide Particles

    NASA Technical Reports Server (NTRS)

    McDaniel, Patricia R. (Inventor); St.Clair, Terry L. (Inventor)

    2002-01-01

    Polymer encapsulated metal oxide particles are prepared by combining a polyamide acid in a polar osmotic solvent with a metal alkoxide solution. The polymer was imidized and the metal oxide formed simultaneously in a refluxing organic solvent. The resulting polymer-metal oxide is an intimately mixed commingled blend, possessing, synergistic properties of both the polymer and preceramic metal oxide. The encapsulated metal oxide particles have multiple uses including, being useful in the production of skin lubricating creams, weather resistant paints, as a filler for paper. making ultraviolet light stable filled printing ink, being extruded into fibers or ribbons, and coatings for fibers used in the production of composite structural panels.

  6. Effect of particle state on the adhesive strength of HVOF sprayed metallic coating

    NASA Astrophysics Data System (ADS)

    Li, Chang-Jiu; Wang, Yu-Yue

    2002-12-01

    NiCrBSi and Ni-50Cr coatings were deposited using the high velocity oxygen fuel (HVOF) spray process under different spray parameters with two powders of different sizes to clarify the influence of the melting state of spray particles on the adhesive strength of the coating. The adhesive strength of the coating was estimated according to the American Society for Testing and Materials (ASTM) C633-79. The melting state of the spray droplet was examined from the coating microstructure. It was found that the melting state of spray particles had a significant effect on the adhesive strength of HVOF sprayed Ni-based coatings. The significant melting of the spray particle did not contribute to the increase in the adhesion of HVOF metallic coatings. On the other hand, the deposition of a partially melted large particle contributed to the substantial improvement of adhesive strength of the HVOF coating. The subsequent coating presented a dense microstructure and yielded an adhesive strength of more than 76 MPa, which was double that of the coating deposited with completely molten particles. It can be suggested that the good melting of the spray particle is mainly related to the mechanical interlocking effect, which reaches the limited and approximately defined adhesive strength up to 40 50 MPa.

  7. Production of Babbitt Coatings by High Velocity Oxygen Fuel (HVOF) Spraying

    NASA Astrophysics Data System (ADS)

    Nascimento, A. R. C.; Ettouil, F. B.; Moreau, C.; Savoie, S.; Schulz, R.

    2017-10-01

    This work presents HVOF as an alternative means to produce dense Babbitt coatings by thermal spray. A radial injection setup and low fuel flow rates were used to minimize heat transfer to the low melting point alloy. In-flight particle diagnostic systems were used to correlate spray parameters with the changes in particle velocity and thermal radiation intensity. The use of particles with larger diameters resulted in higher deposition efficiencies. It was shown that HVOF Babbitt coatings combine a dense structure and a fine distribution of intermetallic phases when compared to more traditional babbitting techniques.

  8. Production of Babbitt Coatings by High Velocity Oxygen Fuel (HVOF) Spraying

    NASA Astrophysics Data System (ADS)

    Nascimento, A. R. C.; Ettouil, F. B.; Moreau, C.; Savoie, S.; Schulz, R.

    2017-08-01

    This work presents HVOF as an alternative means to produce dense Babbitt coatings by thermal spray. A radial injection setup and low fuel flow rates were used to minimize heat transfer to the low melting point alloy. In-flight particle diagnostic systems were used to correlate spray parameters with the changes in particle velocity and thermal radiation intensity. The use of particles with larger diameters resulted in higher deposition efficiencies. It was shown that HVOF Babbitt coatings combine a dense structure and a fine distribution of intermetallic phases when compared to more traditional babbitting techniques.

  9. Aqueous alteration of VHTR fuels particles under simulated geological conditions

    NASA Astrophysics Data System (ADS)

    Ait Chaou, Abdelouahed; Abdelouas, Abdesselam; Karakurt, Gökhan; Grambow, Bernd

    2014-05-01

    Very High Temperature Reactor (VHTR) fuels consist of the bistructural-isotropic (BISO) or tristructural-isotropic (TRISO)-coated particles embedded in a graphite matrix. Management of the spent fuel generated during VHTR operation would most likely be through deep geological disposal. In this framework we investigated the alteration of BISO (with pyrolytic carbon) and TRISO (with SiC) particles under geological conditions simulated by temperatures of 50 and 90 °C and in the presence of synthetic groundwater. Solid state (scanning electron microscopy (SEM), micro-Raman spectroscopy, electron probe microanalyses (EPMA) and X-ray photoelectron spectroscopy (XPS)) and solution analyses (ICP-MS, ionique chromatography (IC)) showed oxidation of both pyrolytic carbon and SiC at 90 °C. Under air this led to the formation of SiO2 and a clay-like Mg-silicate, while under reducing conditions (H2/N2 atmosphere) SiC and pyrolytic carbon were highly stable after a few months of alteration. At 50 °C, in the presence and absence of air, the alteration of the coatings was minor. In conclusion, due to their high stability in reducing conditions, HTR fuel disposal in reducing deep geological environments may constitute a viable solution for their long-term management.

  10. Preparation and characterization of energetic materials coated superfine aluminum particles

    NASA Astrophysics Data System (ADS)

    Liu, Songsong; Ye, Mingquan; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20-50 nm. The active aluminum content of different coated samples was measured by means of oxidation-reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG-DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  11. Effect of carbon coating on scuffing performance in diesel fuels

    SciTech Connect

    Ajayi, O. O.; Alzoubi, M. F.; Erdemir, A.; Fenske, G. R.

    2000-06-29

    Low-sulfur and low-aromatic diesel fuels are being introduced in order to reduce various types of emissions in diesel engines to levels in compliance with current and impending US federal regulations. The low lubricity of these fuels, however, poses major reliability and durability problems for fuel injection components that depend on diesel fuel for their lubrication. In the present study, the authors evaluated the scuff resistance of surfaces in regular diesel fuel containing 500 ppm sulfur and in Fischer-Tropsch synthetic diesel fuel containing no sulfur or aromatics. Tests were conducted with the high frequency reciprocating test rig (HFRR) using 52100 steel balls and H-13 tool-steel flats with and without Argonne's special carbon coatings. Test results showed that the sulfur-containing fuels provide about 20% higher scuffing resistance than does fuel without sulfur. Use of the carbon coating on the flat increased scuffing resistance in both regular and synthetic fuels by about ten times, as measured by the contact severity index at scuffing. Scuffing failure in tests conducted with coated surfaces did not occur until the coating had been removed by the two distinct mechanisms of spalling and wear.

  12. Advances in Automated QA/QC for TRISO Fuel Particle Production

    SciTech Connect

    Hockey, Ronald L.; Bond, Leonard J.; Batishko, Charles R.; Gray, Joseph N.; Saurwein, John J.; Lowden, Richard A.

    2004-06-30

    Fuel in most Generation IV reactor designs typically encompasses billions of the TRISO particles. Present day QA/QC methods, done manually and in many cases destructively, cannot economically test a statistically significant fraction of the large number of the individual fuel particles required. Fully automated inspection technologies are essential to economical TRISO fuel particle production. A combination of in-line nondestructive (NDE) measurements employing electromagnetic induction and digital optical imaging analysis is currently under investigation and preliminary data indicate the potential for meeting the demands of this application. To calibrate high-speed NDE methods, surrogate fuel particle samples are being coated with layers containing a wide array of defect types found to degrade fuel performance and these are being characterized via high-resolution CT and digital radiographic images.

  13. Controlled release with coating layer of permeable particles.

    PubMed

    Ito, Ryusei; Golman, Boris; Shinohara, Kunio

    2003-10-30

    An enhanced method was proposed for controlled release of core material using a coating layer of fine permeable particles dispersed in an impermeable wax prepared by dry-based process. A mathematical model was constructed to describe in detail the core material release by diffusion through the connected permeable particles inside the coating layer. The effective diffusivity was simulated by a random walk method taking into account the structure of the coating layer. The released characteristics were measured for the urea core particle coated with the layer of the starch permeable particles dispersed in the paraffin wax. The calculated results were in a good quantitative agreement with experimental data in all range of coating conditions. As a result, the low release rate was proven to be obtained with thicker coating layer of lower volume fraction of permeable particles. Moreover, the application of permeable particles instead of soluble ones [J. Chem. Eng. Jpn. 35 (2002) 40] resulted in significant decrease in release rate.

  14. Cold spray deposition of Ti2AlC coatings for improved nuclear fuel cladding

    NASA Astrophysics Data System (ADS)

    Maier, Benjamin R.; Garcia-Diaz, Brenda L.; Hauch, Benjamin; Olson, Luke C.; Sindelar, Robert L.; Sridharan, Kumar

    2015-11-01

    Coatings of Ti2AlC MAX phase compound have been successfully deposited on Zircaloy-4 (Zry-4) test flats, with the goal of enhancing the accident tolerance of LWR fuel cladding. Low temperature powder spray process, also known as cold spray, has been used to deposit coatings ∼90 μm in thickness using powder particles of <20 μm. X-ray diffraction analysis showed the phase-content of the deposited coatings to be identical to the powders indicating that no phase transformation or oxidation had occurred during the coating deposition process. The coating exhibited a high hardness of about 800 HK and pin-on-disk wear tests using abrasive ruby ball counter-surface showed the wear resistance of the coating to be significantly superior to the Zry-4 substrate. Scratch tests revealed the coatings to be well-adhered to the Zry-4 substrate. Such mechanical integrity is required for claddings from the standpoint of fretting wear resistance and resisting wear handling and insertion. Air oxidation tests at 700 °C and simulated LOCA tests at 1005 °C in steam environment showed the coatings to be significantly more oxidation resistant compared to Zry-4 suggesting that such coatings can potentially provide accident tolerance to nuclear fuel cladding.

  15. A novel approach to a fine particle coating using porous spherical silica as core particles.

    PubMed

    Ishida, Makoto; Uchiyama, Jumpei; Isaji, Keiko; Suzuki, Yuta; Ikematsu, Yasuyuki; Aoki, Shigeru

    2014-08-01

    Abstract The applicability of porous spherical silica (PSS) was evaluated as core particles for pharmaceutical products by comparing it with commercial core particles such as mannitol (NP-108), sucrose and microcrystalline cellulose spheres. We investigated the physical properties of core particles, such as particle size distribution, flow properties, crushing strength, plastic limit, drying rate, hygroscopic property and aggregation degree. It was found that PSS was a core particle of small particle size, low friability, high water adsorption capacity, rapid drying rate and lower occurrence of particle aggregation, although wettability is a factor to be carefully considered. The aggregation and taste-masking ability using PSS and NP-108 as core particles were evaluated at a fluidized-bed coating process. The functional coating under the excess spray rate shows different aggregation trends and dissolution profiles between PSS and NP-108; thereby, exhibiting the formation of uniform coating under the excess spray rate in the case of PSS. This expands the range of the acceptable spray feed rates to coat fine particles, and indicates the possibility of decreasing the coating time. The results obtained in this study suggested that the core particle, which has a property like that of PSS, was useful in overcoming such disadvantages as large particle size, which feels gritty in oral cavity; particle aggregation; and the long coating time of the particle coating process. These results will enable the practical fine particle coating method by increasing the range of optimum coating conditions and decreasing the coating time in fluidized bed technology.

  16. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Durmazuçar, Hasan H.; Gündüz, Güngör

    2000-12-01

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed.

  17. Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof

    DOEpatents

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir Branko

    2010-04-06

    The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

  18. A novel concept of QUADRISO particles Part III : applications to the plutonium-thorium fuel cycle.

    SciTech Connect

    Talamo, A.

    2009-03-01

    In the present study, a plutonium-thorium fuel cycle is investigated including the {sup 233}U production and utilization. A prismatic thermal High Temperature Gas Reactor (HTGR) and the novel concept of quadruple isotropic (QUADRISO) coated particles, designed at the Argonne National Laboratory, have been used for the study. In absorbing QUADRISO particles, a burnable poison layer surrounds the central fuel kernel to flatten the reactivity curve as a function of time. At the beginning of life, the fuel in the QUADRISO particles is hidden from neutrons, since they get absorbed in the burnable poison before they reach the fuel kernel. Only when the burnable poison depletes, neutrons start streaming into the fuel kernel inducing fission reactions and compensating the fuel depletion of ordinary TRISO particles. In fertile QUADRISO particles, the absorber layer is replaced by natural thorium with the purpose of flattening the excess of reactivity by the thorium resonances and producing {sup 233}U. The above configuration has been compared with a configuration where fissile (neptunium-plutonium oxide from Light Water Reactors irradiated fuel) and fertile (natural thorium oxide) fuels are homogeneously mixed in the kernel of ordinary TRISO particles. For the {sup 233}U utilization, the core has been equipped with europium oxide absorbing QUADRISO particles.

  19. Method of producing encapsulated thermonuclear fuel particles

    DOEpatents

    Smith, Warren H.; Taylor, William L.; Turner, Harold L.

    1976-01-01

    A method of producing a fuel particle is disclosed, which comprises forming hollow spheroids which have a mass number greater than 50, immersing said spheroids while under the presence of pressure and heat in a gaseous atmosphere containing an isotope, such as deuterium and tritium, so as to diffuse the gas into the spheroid and thereafter cooling said spheroids up to about 77.degree. Kelvin to about 4.degree. Kelvin.

  20. Synthesis of sub-micron nickel particles coated onto aluminum powders via a modified polyol process

    NASA Astrophysics Data System (ADS)

    Cheng, J. L.; Hng, H. H.; Ng, H. Y.; Soon, P. C.; Lee, Y. W.

    2008-10-01

    Aluminum is commonly used as a fuel additive for propellants. The main limitations to its use lie in comparatively slow ignition and oxidation/combustion kinetics. Combustion performance of aluminized propellants can be improved through the use of Ni-coated Al particles. Sub-micron to nano-sized particles, with their increased reactivity, also improve combustion performance. Hence, in these contexts, fine Ni particles coated onto commercially available micron-sized Al powders using a modified polyol process were synthesized and evaluated. Ni-coated Al powders of various compositions produced by this method showed significant improvement in oxidation kinetics compared to untreated Al powders. The onset oxidation temperatures for the Ni-coated Al powders were found to be significantly reduced compared to pure untreated Al.

  1. The influence of annealing temperature on the strength of TRISO coated particles

    NASA Astrophysics Data System (ADS)

    van Rooyen, I. J.; Neethling, J. H.; van Rooyen, P. M.

    2010-07-01

    The integrity of the Pebble Bed Modular Reactor (PBMR) fuel, and specifically the SiC layer system of the Tristructural Isotropic (TRISO) coated particle (CP), namely inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon (I-PyC-SiC-O-PyC), determines the containment of fission products. The PBMR fuel consists of TRISO coated particles (CPs) embedded in a graphite matrix. One of the characterization techniques investigated by PBMR is the determination of strength of CPs. It is a well known metallurgical fact that temperature, amongst many other parameters, may influence the strength of a material. A recently developed method for measuring the strength of the TRISO coated particles was used and is briefly described in this article. The advantages of this method are demonstrated by the comparison of strength measurements of five experimental PBMR CP batches as a function of annealing temperature. Significant modification of strength after annealing was measured with increased temperature within the range 1000-2100 °C. The interesting feature of decreasing standard deviation of the strength with increasing temperature will also be discussed with a possible explanation. A significant difference in coated particle strength is also demonstrated for two CP batches with layer thickness on the extremities of the SiC layer thickness specification. The effect of long duration annealing on these strength values will also be demonstrated by comparing results from 1 h to 100 h annealing periods of coated particles at a temperature of 1600 °C.

  2. Stress and Microstructure Development in Particle-Based Coatings

    NASA Astrophysics Data System (ADS)

    Price, Kyle Kirk-Arthur

    Particle-based coatings have a wide range of uses and applications in everyday life. Stress development during the drying process has the potential to impact the performance of the coating. Stress development can be monitored in-situ using a cantilever deflection technique with a laser-photodiode combination. Stress development in the film is directly related to the development of the coating microstructure during drying. Cryogenic scanning electron microscopy (cryoSEM) is a powerful characterization method capable of visualizing the microstructure of the coating during the intermediate stages of drying. Using this method, the coating is frozen to arrest microstructure development and solidify the sample so that it can survive the high-vacuum environment of the SEM. This thesis explores the connections between stress and microstructure development in particle-based coatings during drying. Characterization is often complicated by lateral drying, a common phenomenon in particle-based coatings. To avoid these complications, walled substrates were developed which are used to suppress lateral drying and promote drying uniformity. CryoSEM revealed that latex coatings dried on substrates (with photoresist walls) exhibit a greater degree of drying uniformity. Silicon cantilevers with poly(dimethyl siloxane) (PDMS) walls along the perimeter were used to suppress the effects of lateral drying during stress measurement. The walled cantilevers were used to characterize stress development in ceramic particle coatings and latex films. For the ceramic particle coatings, stress measurements were combined with cryoSEM revealing the origins of stress development in hard particle coatings. Stress development was correlated with the extent of drying and the degree of saturation in the coating. Stress development in latex particle coatings was influenced by the composition and morphology of the latex particles. Additionally, the influence of coalescing aids on stress development was

  3. Preparation of Ti-coated diamond particles by microwave heating

    NASA Astrophysics Data System (ADS)

    Gu, Quanchao; Peng, Jinghui; Xu, Lei; Srinivasakannan, C.; Zhang, Libo; Xia, Yi; Wu, Qingtian; Xia, Hongying

    2016-12-01

    Depositing strong carbide-forming elements on diamond surface can dramatically improve the interfacial bonding strength between diamond grits and metal matrix. In the present work, investigation on the preparation of Ti-coated diamond particles by microwave heating has been conducted. The morphology, microstructure, and the chemical composition of Ti-coated diamond particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometer (EDX). The thickness of Ti coating was measured and the interfacial binding strength between Ti coating and diamond was analyzed. The results show that the surface of the diamond particles could be successfully coated with Ti, forming a uniform and continuous Ti-coated layer. The TiC was found to form between the surface of diamond particles and Ti-coated layer. The amount of TiC as well as the thickness of coating increased with increasing coating temperature, furthermore, the grain size of the coating also grew gradually. The interfacial bonding strength between coating and diamond was found to be best at the temperature of 760 °C.

  4. Observation of nitrate coatings on atmospheric mineral dust particles

    NASA Astrophysics Data System (ADS)

    Li, W. J.; Shao, L. Y.

    2009-03-01

    Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN) activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED). TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite). CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO3)2 and Mg(NO3)2. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3). Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on the climate.

  5. Molten carbonate fuel cell cathode with mixed oxide coating

    DOEpatents

    Hilmi, Abdelkader; Yuh, Chao-Yi

    2013-05-07

    A molten carbonate fuel cell cathode having a cathode body and a coating of a mixed oxygen ion conductor materials. The mixed oxygen ion conductor materials are formed from ceria or doped ceria, such as gadolinium doped ceria or yttrium doped ceria. The coating is deposited on the cathode body using a sol-gel process, which utilizes as precursors organometallic compounds, organic and inorganic salts, hydroxides or alkoxides and which uses as the solvent water, organic solvent or a mixture of same.

  6. Superoleophilic particles and coatings and methods of making the same

    DOEpatents

    Simpson, John T; D& #x27; Urso, Brian

    2013-07-30

    Superoleophilic particles and surfaces and methods of making the same are described. The superoleophilic particles can include porous particles having a hydrophobic coating layer deposited thereon. The coated porous particles are characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m and a plurality of nanopores. Some of the nanopores provide flow through porosity. The superoleophilic particles also include oil pinned within the nanopores of the porous particles The plurality of porous particles can include (i) particles including a plurality of spaced apart nanostructured features comprising a contiguous, protrusive material, (ii) diatomaceous earth particles, or (iii) both. The surfaces can include the superoleophilic particles coupled to the surface.

  7. Residual stresses in high-velocity oxy-fuel metallic coatings

    NASA Astrophysics Data System (ADS)

    Totemeier, T. C.; Wright, R. N.; Swank, W. D.

    2004-06-01

    X-ray based residual stress measurements were made on type 316 stainless steel and Fe3Al coatings that were high-velocity oxy-fuel (HVOF) sprayed onto low-carbon and stainless steel substrates. Nominal coating thicknesses varied from 250 to 1500 µm. The effect of HVOF spray particle velocity on residual stress and deposition efficiency was assessed by preparing coatings at three different torch chamber pressures. The effect of substrate thickness on residual stress was determined by spraying coatings onto thick (6.4 mm) and thin (1.4 mm) substrates. Residual stresses were compressive for both coating materials and increased in magnitude with spray velocity. For coatings applied to thick substrates, near-surface residual stresses were essentially constant with increasing coating thickness. Differences in thermal expansion coefficient between low-carbon and stainless steels led to a 180 MPa difference in residual stress for Fe3Al coatings. Deposition efficiency for both materials is maximized at an intermediate (˜600 m/s) velocity. Considerations for X-ray measurement of residual stresses in HVOF coatings are also presented.

  8. DEM simulation of particle mixing for optimizing the overcoating drum in HTR fuel fabrication

    NASA Astrophysics Data System (ADS)

    Liu, Malin; Lu, Zhengming; Liu, Bing; Shao, Youlin

    2013-06-01

    The rotating drum was used for overcoating coated fuel particles in HTR fuel fabrication process. All the coated particles should be adhered to equal amount of graphite powder, which means that the particle should be mixed quickly in both radial and axial directions. This paper investigated the particle flow dynamics and mixing behavior in different regimes using the discrete element method (DEM). By varying the rotation speed, different flow regimes such as slumping, rolling, cascading, cataracting, centrifuging were produced. The mixing entropy based on radial and axial grid was introduced to describe the radial and axial mixing behaviors. From simulation results, it was found that the radial mixing can be achieved in the cascading regime more quickly than the slumping, rolling and centrifuging regimes, but the traditional rotating drum without internal components can not achieve the requirements of axial mixing and should be improved. Three different structures of internal components are proposed and simulated. The new V-shaped deflectors were found to achieve a quick axial mixing behavior and uniform axial distribution in the rotating drum based on simulation results. At last, the superiority was validated by experimental results, and the new V-shaped deflectors were used in the industrial production of the overcoating coated fuel particles in HTR fuel fabrication process.

  9. The health effects of fossil fuel derived particles.

    PubMed

    Grigg, J

    2002-02-01

    Over the past 10 years there has been increasing evidence that particles generated by the combustion of fossil fuels adversely affect health. To what extent should paediatricians be concerned about particle pollution? This review assesses what we know, and what we still need to know about the health effects of fossil fuel particles.

  10. High-Power Diode Laser Surface Treated HVOF Coating to Combat High Energy Particle Impact Wear

    NASA Astrophysics Data System (ADS)

    Mann, B. S.; Arya, Vivek; Pant, B. K.

    2013-07-01

    High-velocity oxy-fuel (HVOF)-sprayed coatings have performed exceptionally well in low-energy particle impact wear and are accepted worldwide. However, their application for high-energy particle impact wear (HEPIW) requires a different approach and more efforts. HVOF-coating systems typically use WC-Co, WC-Co-Cr, WC-Ni-Cr, and FeCrAlY-Cr3C2 powders. WC-Co-Cr powders are preferred when there is a high demand for corrosion resistance. WC-10Co-4Cr coating powder has been selected in the current study. To improve coating properties such as microhardness, fracture toughness, and HEPIW resistance, a new approach of surface treatment with robotically controlled high-power diode laser (HPDL) is attempted. The robotically controlled HVOF-coating deposition and laser surface treatment were monitored using real-time diagnostic control. The HPDL-treated coating has been compared with "as-sprayed" HVOF coating for HEPIW resistance, fracture toughness, microhardness and microstructure. The coating characteristics and properties after laser surface treatment have improved many times compared with "as-sprayed" HVOF coating. This is due to the elimination of pores in the coating and formation of a metallurgical bond between coating and substrate. This new development opens up a possibility of using such laser treatments in specialized areas where HEPIW damages are acute. The fracture toughness and HEPIW resistance along with optical micrographs of HPDL-treated and untreated HVOF coatings are discussed and reported in this article. HEPIW resistance is observed to be proportional to the product of fracture toughness and microhardness of the HVOF coating.

  11. Do petroleum-based protective coatings add fuel value to slash

    Treesearch

    James L. Murphy; Charles W. Philpot

    1965-01-01

    Asphalts and wax emulsions have been recommended as protective coatings to help obtain clean, safe burns in slash disposal work. Fuel value determinations in the laboratory indicate that such coatings add little to the fuel value of slash.

  12. Coating of uniform inorganic particles with polymers, I

    SciTech Connect

    Oyama, H.T.; Sprycha, R.; Xie, Yuming; Partch, R.E.; Matijevic, E. . Center for Advanced Materials Processing)

    1993-10-15

    Uniform spherical silica particles have been first coated with aluminum hydrous oxide and then with poly(divinylbenzene). To produce the outer shell, the inorganic cores were pretreated with a vinyl coupling agent, then divinylbenzene, and an initiator in hot mineral spirits. The thickness of the alumina or polymer layers could be controlled by adjusting the experimental parameters. The same procedure was used to coat irregularly shaped commercial alumina particles. The charge of the so prepared particles was determined by potentiometric titrations, which showed that the polymer coating was permeable to the reactants. Thus, the titration curves were determined by the properties of the cores.

  13. Microfluidic conformal coating of non-spherical magnetic particles

    PubMed Central

    Moon, Byeong-Ui; Hakimi, Navid; Hwang, Dae Kun; Tsai, Scott S. H.

    2014-01-01

    We present the conformal coating of non-spherical magnetic particles in a co-laminar flow microfluidic system. Whereas in the previous reports spherical particles had been coated with thin films that formed spheres around the particles; in this article, we show the coating of non-spherical particles with coating layers that are approximately uniform in thickness. The novelty of our work is that while liquid-liquid interfacial tension tends to minimize the surface area of interfaces—for example, to form spherical droplets that encapsulate spherical particles—in our experiments, the thin film that coats non-spherical particles has a non-minimal interfacial area. We first make bullet-shaped magnetic microparticles using a stop-flow lithography method that was previously demonstrated. We then suspend the bullet-shaped microparticles in an aqueous solution and flow the particle suspension with a co-flow of a non-aqueous mixture. A magnetic field gradient from a permanent magnet pulls the microparticles in the transverse direction to the fluid flow, until the particles reach the interface between the immiscible fluids. We observe that upon crossing the oil-water interface, the microparticles become coated by a thin film of the aqueous fluid. When we increase the two-fluid interfacial tension by reducing surfactant concentration, we observe that the particles become trapped at the interface, and we use this observation to extract an approximate magnetic susceptibility of the manufactured non-spherical microparticles. Finally, using fluorescence imaging, we confirm the uniformity of the thin film coating along the entire curved surface of the bullet-shaped particles. To the best of our knowledge, this is the first demonstration of conformal coating of non-spherical particles using microfluidics. PMID:25332731

  14. M3FT-15OR0202237: Submit Report on Results From Initial Coating Layer Development For UN TRISO Particles

    SciTech Connect

    Jolly, Brian C.; Lindemer, Terrence; Terrani, Kurt A.

    2015-02-01

    In support of fully ceramic matrix (FCM) fuel development, coating development work has begun at the Oak Ridge National Laboratory (ORNL) to produce tri-isotropic (TRISO) coated fuel particles with UN kernels. The nitride kernels are used to increase heavy metal density in these SiC-matrix fuel pellets with details described elsewhere. The advanced gas reactor (AGR) program at ORNL used fluidized bed chemical vapor deposition (FBCVD) techniques for TRISO coating of UCO (two phase mixture of UO2 and UCx) kernels. Similar techniques were employed for coating of the UN kernels, however significant changes in processing conditions were required to maintain acceptable coating properties due to physical property and dimensional differences between the UCO and UN kernels.

  15. Coated metal sintering carriers for fuel cell electrodes

    SciTech Connect

    Donelson, Richard; Bryson, E. S.

    1998-01-01

    A carrier for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  16. Coated metal sintering carriers for fuel cell electrodes

    DOEpatents

    Donelson, R.; Bryson, E.S.

    1998-11-10

    A carrier is described for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  17. Magnetron sputtering of metallic coatings onto elastomeric substrates for a decrease in fuel permeation rate

    NASA Astrophysics Data System (ADS)

    Myntti, Matthew F.

    The purpose of this research was to investigate the application of a metallic coating by magnetron sputtering onto elastomeric substrates, as an inhibiting layer to permeation transport. The metallic coatings which were deposited were aluminum, titanium, and copper. The substrates used were NBR, FVMQ, and FKM elastomers. The permeating fluids were ASTM Fuel C, isooctane, and toluene. The magnetron sputtering properties of these metallic elements were unique to each material, with the titanium sputtering rate being very low. The sputtering rates of these materials correlated well with their sublimation temperature. It was found that some of the metallic particles which were sputtered onto the substrates, implanted into the surface of the elastomeric membranes, with the total amount and distance of implantation being related to the density of the substrate material. The permeation of these solvents through the composite materials was reduced by the presence of these coatings with the reduction in permeation rate ranging from 12 to 25% for Fuel C. The pervaporation properties of these substrates were also evaluated. It was found from this analysis that for the FVMQ and NBR substrates, the permeation rate of the permeating solute molecules was proportional to the size of the permeation molecule. The substrate materials were not significantly stiffened by the addition of the thin metallic coatings. The coated materials were cohesive and well adhered, as determined by stretching of the substrate materials with the metallic layer in place. Upon stretching, there was no evidence of damage to the metallic coating.

  18. Warm spraying—a novel coating process based on high-velocity impact of solid particles

    PubMed Central

    Kuroda, Seiji; Kawakita, Jin; Watanabe, Makoto; Katanoda, Hiroshi

    2008-01-01

    In recent years, coating processes based on the impact of high-velocity solid particles such as cold spraying and aerosol deposition have been developed and attracting much industrial attention. A novel coating process called ‘warm spraying’ has been developed, in which coatings are formed by the high-velocity impact of solid powder particles heated to appropriate temperatures below the melting point of the powder material. The advantages of such process are as follows: (1) the critical velocity needed to form a coating can be significantly lowered by heating, (2) the degradation of feedstock powder such as oxidation can be significantly controlled compared with conventional thermal spraying where powder is molten, and (3) various coating structures can be realized from porous to dense ones by controlling the temperature and velocity of the particles. The principles and characteristics of this new process are discussed in light of other existing spray processes such as high-velocity oxy-fuel spraying and cold spraying. The gas dynamics of particle heating and acceleration by the spraying apparatus as well as the high-velocity impact phenomena of powder particles are discussed in detail. Several examples of depositing heat sensitive materials such as titanium, metallic glass, WC–Co cermet and polymers are described with potential industrial applications. PMID:27877996

  19. Polymer coatings as separator layers for microbial fuel cell cathodes

    NASA Astrophysics Data System (ADS)

    Watson, Valerie J.; Saito, Tomonori; Hickner, Michael A.; Logan, Bruce E.

    2011-03-01

    Membrane separators reduce oxygen flux from the cathode into the anolyte in microbial fuel cells (MFCs), but water accumulation and pH gradients between the separator and cathode reduces performance. Air cathodes were spray-coated (water-facing side) with anion exchange, cation exchange, and neutral polymer coatings of different thicknesses to incorporate the separator into the cathode. The anion exchange polymer coating resulted in greater power density (1167 ± 135 mW m-2) than a cation exchange coating (439 ± 2 mW m-2). This power output was similar to that produced by a Nafion-coated cathode (1114 ± 174 mW m-2), and slightly lower than the uncoated cathode (1384 ± 82 mW m-2). Thicker coatings reduced oxygen diffusion into the electrolyte and increased coulombic efficiency (CE = 56-64%) relative to an uncoated cathode (29 ± 8%), but decreased power production (255-574 mW m-2). Electrochemical characterization of the cathodes ex situ to the MFC showed that the cathodes with the lowest charge transfer resistance and the highest oxygen reduction activity produced the most power in MFC tests. The results on hydrophilic cathode separator layers revealed a trade off between power and CE. Cathodes coated with a thin coating of anion exchange polymer show promise for controlling oxygen transfer while minimally affecting power production.

  20. Post Irradiation TEM Investigation of ZrN Coated U(Mo) Particles Prepared with FIB

    SciTech Connect

    Van Renterghem, W.; Leenaers, A.; Van den Berghe, S.; Miller, B. D.; Gan, J.; Madden, J. W.; Keiser, D. D.; Palancher, H.; Hofman, G. L.; Breitkreuz, H.

    2015-10-01

    In the framework of the Selenium project, two dispersion fuel plates were fabricated with Si and ZrN coated fuel particles and irradiated in the Br2 reactor of SCK•CEN to high burn-up. The first analysis of the irradiated plate proved the reduced swelling of the fuel plate and interaction layer growth up to 70% burn-up. The question was raised how the structure of the interaction layer had been affected by the irradiation and how the structure of the fuel particles had evolved. Hereto, samples from the ZrN coated UMo particles were prepared for transmission electron microscopy (TEM) using focused ion beam milling (FIB) at INL. The FIB technique allowed to precisely select the area of the interaction layer and/or fuel to produce a sample that is TEM transparent over an area of 20 by 20 µm. In this contribution, the first TEM results will be presented from the 66% burn-up sample.

  1. Methylsilane derived silicon carbide particle coatings produced by fluid-bed chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Miller, James Henry

    This report describes the research effort that was undertaken to develop and understand processing techniques for the deposition of both low and high density SiC coatings from a non-halide precursor, in support of the Generation IV Gas-Cooled Fast Reactor (GFR) fuel development program. The research was conducted in two phases. In the first phase, the feasibility of producing both porous SiC coatings and dense SiC coatings on surrogate fuel particles by fluidized bed chemical vapor deposition (FBCVD) using gas mixtures of methylsilane and argon was demonstrated. In the second phase, a combined experimental and modeling effort was carried out in order to gain an understanding of the deposition mechanisms that result in either porous or dense SiC coatings, depending on the coating conditions. For this second phase effort, a simplified (compared to the fluid bed) single-substrate chemical vapor deposition (CVD) system was employed. Based on the experimental and modeling results, the deposition of SiC from methylsilane is controlled by the extent of gas-phase reaction, and is therefore highly sensitive to temperature. The results show that all SiC coatings are due to the surface adsorption of species that result from gas-phase reactions. The model terms these gas-borne species embryos, and while the model does not include a prediction of coating morphology, a comparison of the model and experimental results indicates that the morphology of the coatings is controlled by the nucleation and growth of the embryos. The coating that results from small embryos (embryos with only two Si-C pairs) appears relatively dense and continuous, while the coating that results from larger embryos becomes less continuous and more nodular as embryo size increases. At some point in the growth of embryos they cease to behave as molecular species and instead behave as particles that grow by either agglomeration or by incorporation of molecular species on their surface. As these particles

  2. Particle fueling and impurity control in PDX

    SciTech Connect

    Fonck, R.J.; Bell, M.; Bol, K.; Budny, R.; Couture, P.; Darrow, D.; Dylla, H.; Goldston, R.; Grek, B.; Hawryluk, R.

    1984-12-01

    Fueling requirements and impurity levels in neutral-beam-heated discharges in the PDX tokamak have been compared for plasmas formed with conventional graphite rail limiters, a particle scoop limiter, and an open or closed poloidal divertor. Gas flows necessary to obtain a given density are highest for diverted discharges and lowest for the scoop limiter. Hydrogen pellet injection provides an efficient alternate fueling technique, and a multiple pellet injector has produced high density discharges for an absorbed neutral beam power of up to 600 kW, above which higher speeds or more massive pellets are required for penetration to the plasma core. Power balance studies indicate that 30 to 40% of the total input power is radiated while approx. 15% is absorbed by the limiting surface, except in the open divertor case, where 60% flows to the neutralizer plate. In all operating configurations, Z/sub eff/ usually rises at the onset of neutral beam injection. Both open divertor plasmas and those formed on a well conditioned water-cooled limiter have Z/sub eff/ less than or equal to 2 at the end of neutral injection. A definitive comparison of divertors and limiters for impurity control purposes requires longer beam pulses or higher power levels than available on present machines.

  3. Data Compilation for AGR-3/4 Designed-to-Fail (DTF) Fuel Particle Batch LEU04-02DTF

    SciTech Connect

    Hunn, John D; Miller, James Henry

    2008-10-01

    This document is a compilation of coating and characterization data for the AGR-3/4 designed-to-fail (DTF) particles. The DTF coating is a high density, high anisotropy pyrocarbon coating of nominal 20 {micro}m thickness that is deposited directly on the kernel. The purpose of this coating is to fail early in the irradiation, resulting in a controlled release of fission products which can be analyzed to provide data on fission product transport. A small number of DTF particles will be included with standard TRISO driver fuel particles in the AGR-3 and AGR-4 compacts. The ORNL Coated Particle Fuel Development Laboratory 50-mm diameter fluidized bed coater was used to coat the DTF particles. The coatings were produced using procedures and process parameters that were developed in an earlier phase of the project as documented in 'Summary Report on the Development of Procedures for the Fabrication of AGR-3/4 Design-to-Fail Particles', ORNL/TM-2008/161. Two coating runs were conducted using the approved coating parameters. NUCO425-06DTF was a final process qualification batch using natural enrichment uranium carbide/uranium oxide (UCO) kernels. After the qualification run, LEU04-02DTF was produced using low enriched UCO kernels. Both runs were inspected and determined to meet the specifications for DTF particles in section 5 of the AGR-3 & 4 Fuel Product Specification (EDF-6638, Rev.1). Table 1 provides a summary of key properties of the DTF layer. For comparison purposes, an archive sample of DTF particles produced by General Atomics was characterized using identical methods. This data is also summarized in Table 1.

  4. Design Optimization of Liquid Fueled High Velocity Oxy- Fuel Thermal Spraying Technique for Durable Coating for Fossil Power Systems

    SciTech Connect

    Choudhuri, Ahsan; Love, Norman

    2016-11-04

    High-velocity oxy–fuel (HVOF) thermal spraying was developed in 1930 and has been commercially available for twenty-five years. HVOF thermal spraying has several benefits over the more conventional plasma spray technique including a faster deposition rate which leads to quicker turn-around, with more durable coatings and higher bond strength, hardness and wear resistance due to a homogeneous distribution of the sprayed particles. HVOF thermal spraying is frequently used in engineering to deposit cermets, metallic alloys, composites and polymers, to enhance product life and performance. HVOF thermal spraying system is a highly promising technique for applying durable coatings on structural materials for corrosive and high temperature environments in advanced ultra-supercritical coal- fired (AUSC) boilers, steam turbines and gas turbines. HVOF thermal spraying is the preferred method for producing coatings with low porosity and high adhesion. HVOF thermal spray process has been shown to be one of the most efficient techniques to deposit high performance coatings at moderate cost. Variables affecting the deposit formation and coating properties include hardware characteristics such as nozzle geometry and spraying distance and process parameters such as equivalence ratio, gas flow density, and powder feedstock. In the spray process, the powder particles experience very high speeds combined with fast heating to the powder material melting point or above. This high temperature causes evaporation of the powder, dissolution, and phase transformations. Due to the complex nature of the HVOF technique, the control and optimization of the process is difficult. In general, good coating quality with suitable properties and required performance for specific applications is the goal in producing thermal spray coatings. In order to reach this goal, a deeper understanding of the spray process as a whole is needed. Although many researchers studied commercial HVOF thermal spray

  5. Design of Aerosol Particle Coating: Thickness, Texture and Efficiency

    PubMed Central

    Buesser, B.; Pratsinis, S.E.

    2013-01-01

    Core-shell particles preserve the performance (e.g. magnetic, plasmonic or opacifying) of a core material while modifying its surface with a shell that facilitates (e.g. by blocking its reactivity) their incorporation into a host liquid or polymer matrix. Here coating of titania (core) aerosol particles with thin silica shells (films or layers) is investigated at non-isothermal conditions by a trimodal aerosol dynamics model, accounting for SiO2 generation by gas phase and surface oxidation of hexamethyldisiloxane (HMDSO) vapor, coagulation and sintering. After TiO2 particles have reached their final primary particle size (e.g. upon completion of sintering during their flame synthesis), coating starts by uniformly mixing them with HMDSO vapor that is oxidized either in the gas phase or on the particles’ surface resulting in SiO2 aerosols or deposits, respectively. Sintering of SiO2 deposited onto the core TiO2 particles takes place transforming rough into smooth coating shells depending on process conditions. The core-shell characteristics (thickness, texture and efficiency) are calculated for two limiting cases of coating shells: perfectly smooth (e.g. hermetic) and fractal-like. At constant TiO2 core particle production rate, the influence of coating weight fraction, surface oxidation and core particle size on coating shell characteristics is investigated and compared to pertinent experimental data through coating diagrams. With an optimal temperature profile for complete precursor conversion, the TiO2 aerosol and SiO2-precursor (HMDSO) vapor concentrations have the strongest influence on product coating shell characteristics. PMID:23729833

  6. Glass coated compressible solid oxide fuel cell seals

    NASA Astrophysics Data System (ADS)

    Rautanen, M.; Thomann, O.; Himanen, O.; Tallgren, J.; Kiviaho, J.

    2014-02-01

    With the growing footprint of solid oxide fuel cell stacks, there is a need to extend the operating range of compressible gaskets towards lower stress levels. This article describes a method to manufacture SOFC seals by coating a compressible sealing material (Thermiculite 866) with glass to obtain good sealing performance even at compression stresses as low as 0.1 MPa. Glass layer can be coated using an organic carrier consisting of terpineol, ethanol and ethyl cellulose. The coated seals can be heat treated by simply ramping the temperature up to operating temperature at 60 Kh-1 and therefore no extra steps, which are typical to glass seals, are required. Coated seals were manufactured using this route and evaluated both ex-situ and in a real stack. Leak rates of 0.1-0.3 ml (m min)-1 were measured at 2-25 mbar overpressure using 50/50 H2/N2. A 30-cell stack was manufactured and tested using coated seals. At nominal operating conditions of 0.25 A cm-2 and 650 °C average cathode temperature, 46% fuel utilization and 20% air utilization the stack had a total hydrogen cross leak of 60 ml min-1 corresponding to 0.7% of the inlet hydrogen flow rate.

  7. Permeation of Military Fuels Through Nitrile-Coated Fabrics Used for Collapsible Fuel Storage Containers

    DTIC Science & Technology

    2014-03-01

    five of the candidate fabrics: the Bell Avon, Dunlop, Eng Fabrics, AmFuel, and Reeves fabrics. However, the Zodiac and Pronal nitrile-coated fabrics...Fife, U.K.), Engineering Fabrics (Rockmart, GA), Zodiac Fabrics Co. (London, Canada), Pronal Elastomer Engineering (Leers, France), Reeves Brothers...permeation rates measured. The three remaining coated fabric materials—BLSS, Zodiac , and Pronal—exhibited significantly lower permeation rates ranging from

  8. Hygroscopic growth and droplet activation of soot particles: uncoated, succinic or sulfuric acid coated

    NASA Astrophysics Data System (ADS)

    Henning, S.; Ziese, M.; Kiselev, A.; Saathoff, H.; Möhler, O.; Mentel, T. F.; Buchholz, A.; Spindler, C.; Michaud, V.; Monier, M.; Sellegri, K.; Stratmann, F.

    2012-05-01

    The hygroscopic growth and droplet activation of uncoated soot particles and such coated with succinic acid and sulfuric acid were investigated during the IN-11 campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility. A GFG-1000 soot generator applying either nitrogen or argon as carrier gas and a miniCAST soot generator were utilized to generate soot particles. Different organic carbon (OC) to black carbon (BC) ratios were adjusted for the CAST-soot by varying the fuel to air ratio. The hygroscopic growth was investigated by means of the mobile Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile) and two different Hygroscopicity Tandem Differential Mobility Analyzers (HTDMA, VHTDMA). Two Cloud Condensation Nucleus Counter (CCNC) were applied to measure the activation of the particles. For the untreated soot particles neither hygroscopic growth nor activation was observed at a supersaturation of 1%, with exception of a partial activation of GFG-soot generated with argon as carrier gas. Coatings of succinic acid lead to a detectable hygroscopic growth of GFG-soot and enhanced the activated fraction of GFG- (carrier gas: argon) and CAST-soot, whereas no hygroscopic growth of the coated CAST-soot was found. Sulfuric acid coatings led to an OC-content dependent hygroscopic growth of CAST-soot. Such a dependence was not observed for activation measurements. Coating with sulfuric acid decreased the amount of Polycyclic Aromatic Hydrocarbons (PAH), which were detected by AMS-measurements in the CAST-soot, and increased the amount of substances with lower molecular weight than the initial PAHs. We assume that these reaction products increased the hygroscopicity of the coated particles in addition to the coating substance itself.

  9. Hygroscopic growth and droplet activation of soot particles: uncoated, succinic or sulfuric acid coated

    NASA Astrophysics Data System (ADS)

    Henning, S.; Ziese, M.; Kiselev, A.; Saathoff, H.; Möhler, O.; Mentel, T. F.; Buchholz, A.; Spindler, C.; Michaud, V.; Monier, M.; Sellegri, K.; Stratmann, F.

    2011-10-01

    The hygroscopic growth and droplet activation of uncoated soot particles and such coated with succinic acid and sulfuric acid were investigated during the IN-11 campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility. A GFG-1000 soot generator applying nitrogen, respectively argon as carrier gas and a miniCAST soot generator were utilized to generate soot particles. Different organic carbon (OC) to black carbon (BC) ratios were adjusted for the CAST-soot by varying the fuel to air ratio. The hygroscopic growth was investigated by means of the mobile Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile) and two different Hygroscopicity Tandem Differential Mobility Analyzers (HTDMA, VHTDMA). Two Cloud Condensation Nucleus Counter (CCNC) were applied to measure the activation of the particles. For the untreated soot particles neither hygroscopic growth nor activation was observed, with exception of a partial activation of GFG-soot generated with argon as carrier gas. Coatings of succinic acid lead to a detectable hygroscopic growth of GFG-soot and enhanced the activated fraction of GFG- (carrier gas: argon) and CAST-soot, whereas no hygroscopic growth of the coated CAST-soot was found. Sulfuric acid coatings lead to an OC-content dependent hygroscopic growth of CAST-soot. Such a dependence was not observed for activation measurements. Coating with sulfuric acid decreased the amount of Polycyclic Aromatic Hydrocarbons (PAH), which were detected by AMS-measurements in the CAST-soot, and increased the amount of substances with lower molecular weight than the initial PAHs. We assume, that these reaction products increased the hygroscopicity of the coated particles in addition to the coating substance itself.

  10. Impact of aromatic concentration in marine fuels on particle emissions

    NASA Astrophysics Data System (ADS)

    Zetterdahl, Maria; Salo, Kent; Fridell, Erik; Sjöblom, Jonas

    2017-09-01

    The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas (SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fuel blends with concentrations of aromatics similar to those found in marine fuel oils, i.e. 20%-30% by volume (%vol.), normal diesel oil (4%-5% vol. aromatics) is doped with a mixture of aromatics. Emission measurements are conducted in test-bed engine facilities and particle emissions over a wide size range are analyzed. Results show a decreased number of particles emitted (or not change) with an increase in the aromatic concentration in fuel. This is because there is a reduction in the cetane number of the fuel with an increased aromatic content, which effects the combustion process and results in decreased particle formation. However, when ignition improver is used to increase the cetane number, particle emissions remain at a lower level than for normal diesel oil; thereby emphasizing the presence of other factors in the formation of particles.

  11. TRISO-Coated Fuel Durability Under Extreme Conditions

    SciTech Connect

    Reimanis, Ivar; Gorman, Brian; Butt, Darryl

    2014-03-30

    The PIs propose to examine TRISO-coated particles (SiC and ZrC coatings) in an integrated two-part study. In the first part, experiments will be performed to assess the reaction kinetics of the carbides under CO-CO2 environments at temperatures up to 1800 degree C. Kinetic model will be applied to describe the degradation. Scanning and transmission electron microscopy will be employed to establish the chemical and microstructure evolution under the imposed environmental conditions. The second part of the proposed work focuses on establishing the role of the high temperature, environmental exposure described above on the mechanical behavior of TRISO-coated particles. Electron microscopy and other advanced techniques will be subsequently performed to evaluate failure mechanisms. The work is expected to reveal relationships between corrosion reactions, starting material characteristics (polytype of SiC, impurity concentration, flaw distribution), flaw healing behavior, and crack growth.

  12. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K. Hartwell; John b. Walter

    2010-10-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  13. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K Hartwell; John B. Walter

    2008-09-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  14. Fuel swelling and interaction layer formation in the SELENIUM Si and ZrN coated U(Mo) dispersion fuel plates irradiated at high power in BR2

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van den Berghe, S.; Koonen, E.; Kuzminov, V.; Detavernier, C.

    2015-03-01

    In the framework of the SELENIUM project two full size flat fuel plates were produced with respectively Si and ZrN coated U(Mo) particles and irradiated in the BR2 reactor at SCK•CEN. Non-destructive analysis of the plates showed that the fuel swelling profiles of both SELENIUM plates were very similar to each other and none of the plates showed signs of pillowing or excessive swelling at the end of irradiation at the highest power position (local maximum 70% 235U). The microstructural analysis showed that the Si coated fuel has less interaction phase formation at low burn-up but at the highest burn-ups, defects start to develop on the IL-matrix interface. The ZrN coated fuel, shows a virtual absence of reaction between the U(Mo) and the Al, up to high fission densities after which the interaction layer formation starts and defects develop in the matrix near the U(Mo) particles. It was found and is confirmed by the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) experiment that there are two phenomena at play that need to be controlled: the formation of an interaction layer and swelling of the fuel. As the interaction layer formation occurs at the U(Mo)-matrix interface, applying a diffusion barrier (coating) at that interface should prevent the interaction between U(Mo) and the matrix. The U(Mo) swelling, observed to proceed at an accelerating rate with respect to fission density accumulation, is governed by linear solid state swelling and fission gas bubble swelling due to recrystallization of the fuel. The examination of the SELENIUM fuel plates clearly show that for the U(Mo) dispersion fuel to be qualified, the swelling rate at high burn-up needs to be reduced.

  15. Diffusivities of Ag, Cs, Sr, and Kr in TRISO fuel particles and graphite

    SciTech Connect

    Collin, Blaise Paul

    2016-09-01

    Tri-structural isotropic (TRISO) coated particles have been developed and studied since the late 1950s when the concept of coated particles was invented by Roy Huddle of the United Kingdom Atomic Energy Authority. Several decades of work by half a dozen countries on fission product transport in TRISO fuel through numerous irradiation and heating experiments have led to several recommendations of transport data and to the adoption of various sets of diffusion coefficients. In 1997, the International Atomic Energy Agency (IAEA) gathered all these historical results and issued a technical document (TECDOC-978 [IAEA]) that summarizes these sets of recommended diffusion coefficients. Table 1 shows the reference literature articles for the diffusivities that have historically been recommended by the American and German TRISO fuel development programs and that are summarized in the IAEA report (see section 7 for full references of these articles).

  16. MINING PROCESS AND PRODUCT INFORMATION FROM PRESSURE FLUCTUATIONS WITHIN A FUEL PARTICLE COATER

    SciTech Connect

    Douglas W. Marshall; Charles M. Barnes

    2008-09-01

    The Next Generation Nuclear Power (NGNP) Fuel Development and Qualification Program included the design, installation, and testing of a 6-inch diameter nuclear fuel particle coater to demonstrate quality TRISO fuel production on a small industrial scale. Scale-up from the laboratory-scale coater faced challenges associated with an increase in the kernel charge mass, kernel diameter, and a redesign of the gas distributor to achieve adequate fluidization throughout the deposition of the four TRISO coating layers. TRISO coatings are applied at very high temperatures in atmospheres of dense particulate clouds, corrosive gases, and hydrogen concentrations over 45% by volume. The severe environment, stringent product and process requirements, and the fragility of partially-formed coatings limit the insertion of probes or instruments into the coater vessel during operation. Pressure instrumentation were installed on the gas inlet line and exhaust line of the 6-inch coater to monitor the bed differential pressure and internal pressure fluctuations emanating from the fuel bed as a result of bed and gas “bubble” movement. These instruments are external to the particle bed and provide a glimpse into the dynamics of fuel particle bed during the coating process and data that could be used to help ascertain the adequacy of fluidization and, potentially, the dominant fluidization regimes. Pressure fluctuation and differential pressure data are not presently useful as process control instruments, but data suggest a link between the pressure signal structure and some measurable product attributes that could be exploited to get an early estimate of the attribute values.

  17. Detection and analysis of particles with failed SiC in AGR-1 fuel compacts

    DOE PAGES

    Hunn, John D.; Baldwin, Charles A.; Gerczak, Tyler J.; ...

    2016-04-06

    As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of 134Cs and 137Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compactmore » containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during irradiation testing or post-irradiation safety testing at 1600–1800 °C were identified, and individual particles with abnormally low cesium retention were sorted out with the Oak Ridge National Laboratory (ORNL) Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. In addition, all three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were related to either fabrication defects or showed extensive Pd corrosion through the SiC where it had been exposed by similar IPyC cracking.« less

  18. Detection and analysis of particles with failed SiC in AGR-1 fuel compacts

    SciTech Connect

    Hunn, John D.; Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M.; Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A.

    2016-04-06

    As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of 134Cs and 137Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during irradiation testing or post-irradiation safety testing at 1600–1800 °C were identified, and individual particles with abnormally low cesium retention were sorted out with the Oak Ridge National Laboratory (ORNL) Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. In addition, all three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were related to either fabrication defects or showed extensive Pd corrosion through the SiC where it had been exposed by similar IPyC cracking.

  19. Dry particle coating of polymer particles for tailor-made product properties

    SciTech Connect

    Blümel, C. Schmidt, J. Dielesen, A. Sachs, M. Winzer, B. Peukert, W. Wirth, K.-E.

    2014-05-15

    Disperse polymer powders with tailor-made particle properties are of increasing interest in industrial applications such as Selective Laser Beam Melting processes (SLM). This study focuses on dry particle coating processes to improve the conductivity of the insulating polymer powder in order to assemble conductive devices. Therefore PP particles were coated with Carbon Black nanoparticles in a dry particle coating process. This process was investigated in dependence of process time and mass fraction of Carbon Black. The conductivity of the functionalized powders was measured by impedance spectroscopy. It was found that there is a dependence of process time, respectively coating ratio and conductivity. The powder shows higher conductivities with increasing number of guest particles per host particle surface area, i.e. there is a correlation between surface functionalization density and conductivity. The assembled composite particles open new possibilities for processing distinct polymers such as PP in SLM process. The fundamentals of the dry particle coating process of PP host particles with Carbon Black guest particles as well as the influence on the electrical conductivity will be discussed.

  20. Development of Particle Interface Bonding in Thermal Spray Coatings: A Review

    NASA Astrophysics Data System (ADS)

    Li, Chang-Jiu; Yang, Guan-Jun; Li, Cheng-Xin

    2013-03-01

    Thermal spray ceramic coatings deposited following the conventional routine exhibit a typical lamellar structure with a limited interface bonding ratio. The bonding between particles in the coating dominates coating properties and performance. In this review paper, the bonding formation at the interface between thin lamellae in the coating is examined. The effect of spray parameters on the bonding ratio is presented to reveal the main droplet parameters controlling bonding formation, which reveals that the temperature of the spray particle rather than its velocity dominates the bonding formation. The limitation to increase significantly the ceramic particle temperature inherent to the thermal spray process leads to the observation of a maximum bonding ratio of about 32%, while through controlling the surface temperature of the coating prior to molten droplet impact, the bonding at the lamellar interface can be significantly increased. Consequently, it is shown that with the proper selection of deposition conditions and control of the deposition temperature, the bonding ratio of ceramic deposits can be altered from a maximum of 32% for a conventional deposit to a maximum of 100%. Such wide adjustability of the lamellar bonding opens new possibilities for using thermal spray coatings in various applications requiring different microstructures and properties. The examination of recent studies shows that the bonding control makes it possible to fabricate porous deposits through surface-molten particles. Such an approach could be applied for the fabrication of porous materials, the deposition of high temperature abradable ceramic coatings, and for forming functional structured surfaces, such as a surface with super-hydrophobicity or a solid oxide fuel cell cathode interface with high specific surface area and high catalytic performance. Furthermore, complete interface bonding leads to crystalline structure control of individual splats through epitaxial grain growth.

  1. Protection of porous carbon fuel particles from boudouard corrosion

    DOEpatents

    Cooper, John F.

    2015-05-26

    A system for producing energy that includes infusing porous carbon particles produced by pyrolysis of carbon-containing materials with an off-eutectic salt composition thus producing pore-free carbon particles, and reacting the carbon particles with oxygen in a fuel cell according to the reaction C+O.sub.2=CO.sub.2 to produce electrical energy.

  2. Nuclear fuels status

    NASA Technical Reports Server (NTRS)

    Kania, Michael

    1991-01-01

    A discussion on coated particle fuel performance from a modular High Temperature Gas Reactor (HTGR) is presented along with experimental results. The following topics are covered: (1) the coated particle fuel concept; (2) the functional requirements; (3) performance limiting mechanisms; (4) fuel performance; and (5) methods/techniques for characterizing performance.

  3. Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

    SciTech Connect

    Van Rooyen, Isabella Johanna; Demkowicz, Paul Andrew; Riesterer, Jessica Lori; Miller, Brandon Douglas; Janney, Dawn Elizabeth; Harp, Jason Michael; Ploger, Scott Arden

    2012-12-01

    The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO2 kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

  4. Reaction synthesis of Ni-Al based particle composite coatings

    SciTech Connect

    SUSAN,DONALD F.; MISIOLEK,WOICECK Z.; MARDER,ARNOLD R.

    2000-02-11

    Electrodeposited metal matrix/metal particle composite (EMMC) coatings were produced with a nickel matrix and aluminum particles. By optimizing the process parameters, coatings were deposited with 20 volume percent aluminum particles. Coating morphology and composition were characterized using light optical microscopy (LOM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Differential thermal analysis (DTA) was employed to study reactive phase formation. The effect of heat treatment on coating phase formation was studied in the temperature range 415 to 1,000 C. Long-time exposure at low temperature results in the formation of several intermetallic phases at the Ni matrix/Al particle interfaces and concentrically around the original Al particles. Upon heating to the 500--600 C range, the aluminum particles react with the nickel matrix to form NiAl islands within the Ni matrix. When exposed to higher temperatures (600--1,000 C), diffusional reaction between NiAl and nickel produces ({gamma})Ni{sub 3}Al. The final equilibrium microstructure consists of blocks of ({gamma}{prime})Ni{sub 3}Al in a {gamma}(Ni) solid solution matrix, with small pores also present. Pore formation is explained based on local density changes during intermetallic phase formation and microstructural development is discussed with reference to reaction synthesis of bulk nickel aluminides.

  5. Thermo-physical characteristics of nickel-coated aluminum powder as a function of particle size and oxidant

    NASA Astrophysics Data System (ADS)

    Lee, Sanghyup; Noh, Kwanyoung; Lim, Jihwan; Yoon, Woongsup

    2016-10-01

    Aluminum particles 15-25 µm in size are widely used in fuel propellants and underwater propulsion systems in national defense research. However, these particles are covered with an aluminum oxide film, which has a high melting point, so ignition is difficult. To improve the ignitability of high-energy aluminum powder and to understand the reaction phenomenon as a function of particle size(15-25 µm, 74-105 µm, and 2.38 mm) and oxidizer(air, CO2, and argon), the natural oxide films are chemically removed. The particles are then coated with nickel using an electro-less method. The degree of nickel deposition is confirmed qualitatively and quantitatively through surface analysis using scanning electron microscopy/energy dispersive spectroscopy. To characterize the nickel coatings, elemental analysis is also conducted by using X-ray diffraction. Thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) enable comparisons between the uncoated and coated aluminum, and the reaction process are investigated through fine structural analysis of the particle surfaces and cross sections. There are little difference in reactivity as a function of oxidant type. However, a strong exothermic reaction in the smaller nickel-coated aluminum particles near the melting point of aluminum accelerates the reaction of the smaller particles. Explanation of the reactivity of the nickel-coated aluminum depending on the particle sizes is attempted.

  6. Impact dynamics of particle-coated droplets

    NASA Astrophysics Data System (ADS)

    Supakar, T.; Kumar, A.; Marston, J. O.

    2017-01-01

    We present findings from an experimental study of the impact of liquid marbles onto solid surfaces. Using dual-view high-speed imaging, we reveal details of the impact dynamics previously not reported. During the spreading stage it is observed that particles at the surface flow rapidly to the periphery of the drop, i.e., the lamella. We characterize the spreading with the maximum spread diameter, comparing to impacts of pure liquid droplets. The principal result is a power-law scaling for the normalized maximum spread in terms of the impact Weber number, Dmax/D0˜Weα , with α ≈1 /3 . However, the best description of the spreading is obtained by considering a total energy balance, in a similar fashion to Pasandideh-Fard et al. [Phys. Fluids 8, 650 (1996)], 10.1063/1.868850. By using hydrophilic target surfaces, the marble integrity is lost even for moderate impact speeds as the particles at the surface separate and allow liquid-solid contact to occur. Remarkably, however, we observe no significant difference in the maximum spread between hydrophobic and hydrophilic targets, which is rationalized by the presence of the particles. Finally, for the finest particles used, we observe the formation of nonspherical arrested shapes after retraction and rebound from hydrophobic surfaces, which is quantified by a circularity measurement of the side profiles.

  7. Manufacturing and Properties of High-Velocity Oxygen Fuel (HVOF)-Sprayed FeVCrC Coatings

    NASA Astrophysics Data System (ADS)

    Sassatelli, Paolo; Bolelli, Giovanni; Lusvarghi, Luca; Manfredini, Tiziano; Rigon, Rinaldo

    2016-10-01

    This paper studies the microstructure, sliding wear behavior and corrosion resistance of high-velocity oxygen fuel (HVOF)-sprayed FeVCrC-based coatings. Various process parameters were tested to evaluate their effects on the coating properties, which were also compared to those of HVOF-sprayed NiCrBSi and Stellite-6 coatings. The Fe alloy coatings are composed of flattened splats, originating from molten droplets and consisting of a super-saturated solid solution, together with rounded particles, coming from partially unmolten material and containing V- and Fe-based carbide precipitates. All process parameters, apart from "extreme" settings with excess comburent in the flame, produce dense coatings, indicating that the feedstock powder is quite easily processable by HVOF. These coatings, with a microhardness of 650-750 HV0.3, exhibit wear rates of ≈2 × 10-6 mm3/(Nm) in ball-on-disk tests against sintered Al2O3 spheres. They perform far better than the reference coatings, and better than other Fe- and Ni-based alloy coatings tested in previous research. On the other hand, the corrosion resistance of the coating material (tested by electrochemical polarization in 0.1 M HCl solution) is quite low. Even in the absence of interconnected porosity, this results in extensive, selective damage to the Fe-based matrix. This coating material is therefore unadvisable for severely corrosive environments.

  8. The Effect of HVOF Particle-Substrate Interactions on Local Variations in the Coating Microstructure and the Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Racek, Ondrej

    2010-09-01

    Splashing and redeposition of droplets occur during thermal spray processing, which affects the coating porosity and morphology. Therefore, this phenomenon is important from a practical point of view such as corrosion. Particle interaction with substrate is a function of the particle velocity, viscosity, temperature, as well as the substrate temperature, chemistry, roughness, and geometry. In the present study, the splashing phenomenon was studied on CrC-NiCr and stainless steel materials deposited using the high velocity oxygen fuel process. The effect of particle splashing on the coating microstructure was investigated with respect to the corrosion properties. Particle behavior during impact was explained based on in-flight particle velocity and temperature measurements. It was found that the conditions that favor particle splashing promote occurrence of localized porosity. The localized porosity was a strong function of the substrate curvature and originated from the substrate asperities.

  9. Controlling the scattering properties of thin, particle-doped coatings

    NASA Astrophysics Data System (ADS)

    Rogers, William; Corbett, Madeleine; Manoharan, Vinothan

    2013-03-01

    Coatings and thin films of small particles suspended in a matrix possess optical properties that are important in several industries from cosmetics and paints to polymer composites. Many of the most interesting applications require coatings that produce several bulk effects simultaneously, but it is often difficult to rationally formulate materials with these desired optical properties. Here, we focus on the specific challenge of designing a thin colloidal film that maximizes both diffuse and total hemispherical transmission. We demonstrate that these bulk optical properties follow a simple scaling with two microscopic length scales: the scattering and transport mean free paths. Using these length scales and Mie scattering calculations, we generate basic design rules that relate scattering at the single particle level to the film's bulk optical properties. These ideas will be useful in the rational design of future optically active coatings.

  10. Solid Hydrogen Particles Analyzed for Atomic Fuels

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2001-01-01

    Solid hydrogen particles have been selected as a means of storing atomic propellants in future launch vehicles (refs. 1 to 2). In preparation for this, hydrogen particle formation in liquid helium was tested experimentally. These experiments were conducted to visually characterize the particles and to observe their formation and molecular transformations (aging) while in liquid helium. The particle sizes, molecular transformations, and agglomeration times were estimated from video image analyses. The experiments were conducted at the NASA Glenn Research Center in the Supplemental Multilayer Insulation Research Facility (SMIRF, ref. 3). The facility has a vacuum tank, into which the experimental setup was placed. The vacuum tank prevented heat leaks and subsequent boiloff of the liquid helium, and the supporting systems maintained the temperature and pressure of the liquid helium bath where the solid particles were created. As the operation of the apparatus was developed, the hydrogen particles were easily visualized. The figures (ref. 1) show images from the experimental runs. The first image shows the initial particle freezing, and the second image shows the particles after the small particles have agglomerated. The particles finally all clump, but stick together loosely. The solid particles tended to agglomerate within a maximum of 11 min, and the agglomerate was very weak. Because the hydrogen particles are buoyant in the helium, the agglomerate tends to compact itself into a flat pancake on the surface of the helium. This pancake agglomerate is easily broken apart by reducing the pressure above the liquid. The weak agglomerate implies that the particles can be used as a gelling agent for the liquid helium, as well as a storage medium for atomic boron, carbon, or hydrogen. The smallest particle sizes that resulted from the initial freezing experiments were about 1.8 mm. About 50 percent of the particles formed were between 1.8 to 4.6 mm in diameter. These very

  11. Manufacture of bonded-particle nuclear fuel composites

    DOEpatents

    Stradley, J.G.; Sease, J.D.

    1973-10-01

    A preselected volume of nuclear fuel particles are placed in a cylindrical mold cavity followed by a solid pellet of resin--carbon matrix material of preselected volume. The mold is heated to liquefy the pellet and the liquefied matrix forced throughout the interstices of the fuel particles by advancing a piston into the mold cavity. Excess matrix is permitted to escape through a vent hole in the end of the mold opposite to that end where the pellet was originally disposed. After the matrix is resolidified by cooling, the resultant fuel composite is removed from the mold and the resin component of the matrix carbonized. (Official Gazette)

  12. Composite of ceramic-coated magnetic alloy particles

    DOEpatents

    Moorhead, Arthur J.; Kim, Hyoun-Ee

    2000-01-01

    A composite structure and method for manufacturing same, the composite structure being comprised of metal particles and an inorganic bonding media. The method comprises the steps of coating particles of a metal powder with a thin layer of an inorganic bonding media selected from the group of powders consisting of a ceramic, glass, and glass-ceramic. The particles are assembled in a cavity and heat, with or without the addition of pressure, is thereafter applied to the particles until the layer of inorganic bonding media forms a strong bond with the particles and with the layer of inorganic bonding media on adjacent particles. The resulting composite structure is strong and remains cohesive at high temperatures.

  13. Effectiveness of Cool Roof Coatings with Ceramic Particles

    SciTech Connect

    Brehob, Ellen G; Desjarlais, Andre Omer; Atchley, Jerald Allen

    2011-01-01

    Liquid applied coatings promoted as cool roof coatings, including several with ceramic particles, were tested at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tenn., for the purpose of quantifying their thermal performances. Solar reflectance measurements were made for new samples and aged samples using a portable reflectometer (ASTM C1549, Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer) and for new samples using the integrating spheres method (ASTM E903, Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres). Thermal emittance was measured for the new samples using a portable emissometer (ASTM C1371, Standard Test Method for Determination of Emittance of Materials Near Room 1 Proceedings of the 2011 International Roofing Symposium Temperature Using Portable Emissometers). Thermal conductivity of the coatings was measured using a FOX 304 heat flow meter (ASTM C518, Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus). The surface properties of the cool roof coatings had higher solar reflectance than the reference black and white material, but there were no significant differences among coatings with and without ceramics. The coatings were applied to EPDM (ethylene propylene diene monomer) membranes and installed on the Roof Thermal Research Apparatus (RTRA), an instrumented facility at ORNL for testing roofs. Roof temperatures and heat flux through the roof were obtained for a year of exposure in east Tennessee. The field tests showed significant reduction in cooling required compared with the black reference roof (~80 percent) and a modest reduction in cooling compared with the white reference roof (~33 percent). The coating material with the highest solar reflectivity (no ceramic particles) demonstrated the best overall thermal performance (combination of reducing the

  14. Deposition of composite coatings from particle-particle and particle-yeast blends by convective-sedimentation assembly.

    PubMed

    Jenkins, Jessica S; Flickinger, Michael C; Velev, Orlin D

    2012-08-15

    The structures resulting from convective-sedimentation assembly (CSA) of bimodal suspensions (4.1-10% solids) of strongly charged sulfate latex microspheres (zeta potential -55.9±1.8 mV at pH 8.0) and weakly charged Saccharomyces cerevisiae (zeta potential -18.7±0.71 mV at pH 8.0) on glass, polyester, polypropylene, and aluminum foil substrates was evaluated. This study shows how substrate wettability, suspension composition, particle size ratio and surface charge affect the deposition process and resulting coating microstructure (particle ordering and void space). Size ratio and charge influence deposition, convective mixing or demixing and relative particle locations. Substrate wettability and suspension composition influence coating microstructure by controlling suspension delivery and spreading across the substrate. S. cerevisiae behave like negatively-charged colloidal particles during CSA. CSA of particle-yeast blends result in open-packed structures (15-45% mean void space), instead of tightly packed coatings attainable with single component systems, confirming the existence of significant polymer particle-yeast interactions and formation of particle aggregates that disrupt coating microstructure during deposition. Further optimization of the process should allow void space reduction and deposition of cells plus adhesive polymer particles into tightly packed adhesive monolayer coatings for biosensors, biophotoabsorbers, energy applications, and highly reactive microbial absorbers. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. On-line nondestructive methods for examining fuel particles

    SciTech Connect

    Pardini, A.F.; Bond, L.J.; Good, M.S.; Bunch, K.J.; Sandness, G.A.; Hockey, R.L.; Saurwein, J.J.; Gray, J.N.

    2007-07-01

    Tri-isotropic (TRISO) particle fuels are being considered for use in various advanced nuclear power reactors and about 15 billion of these small ({approx} 1 mm diameter) spheres are needed for a single fuel load. Current quality control methods are manual, often destructive of test specimens, and they are economically impractical for automated application at commercial scale. Replacing these methods with new nondestructive evaluation techniques, automated for higher speed, will make fuel production and reactor operation economically more attractive. This paper reports aspects of a project to develop and demonstrate nondestructive examination methods to detect and reject defective particles. The work explored adapting, developing, and demonstrating innovative nondestructive test methods to cost-effectively assure the quality of large percentages of the fuel particles. (authors)

  16. Fuel performance improvement program. The development of graphite-coated cladding for improved PCI performance of LWR fuels

    SciTech Connect

    Bunnell, L.R.; Welty, R.K.

    1981-06-01

    One of the fuel concepts being tested and demonstrated as part of the Fuel Performance Improvement Program includes a graphite coating applied to the inner surface of the Zircaloy cladding. The technology for producing acceptable coatings was developed starting with the selection of a suitable graphite and culminating with the coating of 200 cladding tubes for demonstration irradiations in the Big Rock Point Reactor. During the process development, methods for controlling the coating thickness and minimizing its hydrogen content were developed that were compatible with production scale operation. During the same period, the graphite coatings were characterized and their properties were determined, mainly to provide information needed for fuel design and licensing considerations. Purity, structure, coating-to-cladding compatibility, thermal conductivity, and friction/wear characteristics were measured.

  17. Calculation of the pressure vessel failure fraction of fuel particle of gas turbine high temperature reactor 300 C

    SciTech Connect

    Aihara, J.; Ueta, S.; Mozumi, Y.; Sato, H.; Sawa, K.; Motohashi, Y.

    2007-07-01

    In high temperature gas-cooled reactors (HTGRs), coated particles are used as fuels. For upgrading HTGR technologies, present SiC coating layer which is used as the 3. layer could be replaced with ZrC coating layer which have much higher temperature stability in addition to higher resistance to chemical attack by fission product palladium than the SiC coating layer. The ZrC layer could deform plastically at high temperatures. Therefore, the Japan Atomic Energy Agency modified an existing pressure vessel failure fraction calculation code to treat the plastic deformation of the 3. layer in order to predict failure fraction of ZrC coated particle under irradiation. Finite element method is employed to calculate the stress in each coating layer. The pressure vessel failure fraction of the coated fuel particles under normal operating condition of GTHTR300C is calculated by the modified code. The failure fraction is evaluated as low as 3.5 x 10{sup -6}. (authors)

  18. Coating of zinc ferrite particles with a conducting polymer, polyaniline.

    PubMed

    Stejskal, Jaroslav; Trchová, Miroslava; Brodinová, Jitka; Kalenda, Petr; Fedorova, Svetlana V; Prokes, Jan; Zemek, Josef

    2006-06-01

    Particles of zinc ferrite, ZnOFe2O3, were coated with polyaniline (PANI) phosphate during the in situ polymerization of aniline in an aqueous solution of phosphoric acid. The PANI-ferrite composites were characterized by FTIR spectroscopy. X-ray photoelectron spectroscopy was used to determine the degree of coating with a conducting polymer. Even a low content of PANI, 1.4 wt%, resulted in the 45% coating of the particles' surface. On the other hand, even at high PANI content, the coating of ferrite surface did not exceeded 90%. This is explained by the clustering of hydrophobic aniline oligomers at the hydrophilic ferrite surface and the consequent irregular PANI coating. The conductivity increased from 2 x 10(-9) to 6.5 S cm(-1) with increasing fraction of PANI phosphate in the composite. The percolation threshold was located at 3-4 vol% of the conducting component. In the absence of any acid, a conducting product, 1.4 x 10(-2) Scm(-1), was also obtained. As the concentration of phosphoric acid increased to 3 M, the conductivity of the composites reached 1.8 S cm(-1) at 10-14 wt% of PANI. The ferrite alone can act as an oxidant for aniline; a product having a conductivity 0.11 S cm(-1) was obtained after a one-month immersion of ferrite in an acidic solution of aniline.

  19. Particle Count Limits Recommendation for Aviation Fuel

    DTIC Science & Technology

    2015-10-05

    gravimetric measurements need to be taken to determine if poor measurement repeatability accounts for false negatives. • Photograph failed...ASTM D2276 – Particulate Contamination in Aviation Fuel by Line Sampling – gravimetric limit 1.0 mg/L (MIL-STD-3004, MIL-DTL-83133) • JP-4 and JP-5...Filtration – gravimetric limit 1.0 mg/L (MIL-STD-3004) • ASTM D3240 – Undissolved Water in Aviation Turbine Fuels – 10 PPM (MIL-STD-3004, ATP 4-43

  20. Reactor Physics Parametric and Depletion Studies in Support of TRISO Particle Fuel Specification for the Next Generation Nuclear Plant

    SciTech Connect

    James W. Sterbentz; Bren Phillips; Robert L. Sant; Gray S. Chang; Paul D. Bayless

    2003-09-01

    Reactor physics calculations were initiated to answer several major questions related to the proposed TRISO-coated particle fuel that is to be used in the prismatic Very High Temperature Reactor (VHTR) or the Next Generation Nuclear Plant (NGNP). These preliminary design evaluation calculations help ensure that the upcoming fuel irradiation tests will test appropriate size and type of fuel particles for a future NGNP reactor design. Conclusions from these calculations are expected to confirm and suggest possible modifications to the current particle fuel parameters specified in the evolving Fuel Specification. Calculated results dispel the need for a binary fuel particle system, which is proposed in the General Atomics GT-MHR concept. The GT-MHR binary system is composed of both a fissile and fertile particle with 350- and 500- micron kernel diameters, respectively. For the NGNP reactor, a single fissile particle system (single UCO kernel size) can meet the reactivity and power cycle length requirements demanded of the NGNP. At the same time, it will provide substantial programmatic cost savings by eliminating the need for dual particle fabrication process lines and dual fuel particle irradiation tests required of a binary system. Use of a larger 425-micron kernel diameter single fissile particle (proposed here), as opposed to the 350-micron GT-MHR fissile particle size, helps alleviate current compact particle packing fractions fabrication limitations (<35%), improves fuel block loading for higher n-batch reload options, and tracks the historical correlation between particle size and enrichment (10 and 14 wt% U-235 particle enrichments are proposed for the NGNP). Overall, the use of the slightly larger kernel significantly broadens the NGNP reactor core design envelope and provides increased design margin to accommodate the (as yet) unknown final NGNP reactor design. Maximum power-peaking factors are calculated for both the initial and equilibrium NGNP cores

  1. Cold sprayed copper coating: numerical study of particle impact and coating characterization

    NASA Astrophysics Data System (ADS)

    Mebdoua, Yamina; Fizi, Yazid; Bouhelal, Nadjet

    2016-05-01

    Cold spraying technique is a promising process fabricating high quality metallic coatings. This work concerns both numerical and experimental investigations of cold sprayed copper coating taking into account impact conditions including, particle velocities and temperature, gas pressure and material nature. The conducted numerical study is an examination of the deformation behavior of Cu particles sprayed onto steel substrate using Abaqus/explicit software, allowing a good understanding of the deposition characteristics of copper particles and the effect of particle velocity on the coating microstructure. The numerical results show that particle impact velocity has a significant effect on its morphology; Lagrangian method exhibits an excessive distortion of the elements in the case of high impact velocity and fine meshing size, whereas simulation of particle impact using arbitrary Lagrangian-Eulerian (ALE) method is close to the experimental observations. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  2. Optical Anisotropy Measurements of TRISO Nuclear Fuel Particle Cross-Sections: The Method

    SciTech Connect

    Jellison Jr, Gerald Earle; Hunn, John D

    2008-01-01

    The analysis of two-modulator generalized ellipsometry microscope (2-MGEM) data to extract information on the optical anisotropy of coated particle fuel layers is discussed. Using a high resolution modification to the 2-MGEM, it is possible to obtain generalized ellipsometry images of coating layer cross-sections with a pixel size of 2.5 m and an optical resolution of ~ 4 m. The most important parameter that can be extracted from these ellipsometry images is the diattenuation, which can be directly related to the optical anisotropy factor (OAF or OPTAF) used in previous characterization studies of tristructural isotropic (TRISO) coated particles. Because high resolution images can be obtained, the data for each coating layer contains >6,000 points, allowing considerable statistical analysis. This analysis has revealed that the diattenuation of the inner pyrocarbon (IPyC) and outer pyrocarbon (OPyC) coatings varies significantly throughout the layer. The 2-MGEM data can also be used to determine the principal axis angle of the pyrocarbon layers, which is nearly perpendicular to the TRISO radius (i.e., growth direction) and corresponds to the average orientation of the graphine planes.

  3. Particle-based simulations of powder coating in additive manufacturing suggest increase in powder bed roughness with coating speed

    NASA Astrophysics Data System (ADS)

    Parteli, Eric J. R.; Pöschel, Thorsten

    2017-06-01

    We have developed the first particle-based numerical tool to simulate the coating of powder particles in additive manufacturing devices. Our Discrete Element Method considers realistic particle shapes and incorporates attractive interaction (van-der-Waals) forces between the particles. From simulations of powder coating using a roller as coating device, we find that the surface roughness of the powder bed scales with the square of coating speed. Moreover, we find that using fine, highly polydisperse powders may lead to larger powder bed roughness, compared to process simulations using coarser powders, due to the formation of agglomerates resulting from cohesive forces.

  4. Microstructural characterization of small-particle plasma spray coatings

    SciTech Connect

    Arellano-Lopez, A.R. de; Faber, K.T.

    1999-08-01

    The microstructure of a small-particle plasma spray (SPPS) aluminum oxide coating sprayed onto a prepared mild steel substrate has been characterized using a variety of microscopic techniques as part of a process optimization study. The coating was highly conforming to the substrate as evidenced in high-resolution transmission electron microscopy, although some voids were present at the interface. The layered splat microstructure, characteristic of conventional plasma-sprayed coatings but smaller in size, was discerned in partially thinned samples in a focused-ion-beam scanning electron microscope (FIB-SEM). Microcracks and microporosity, generally less than 0.5 {micro}m in size, was also seen between splats using transmission electron microscopy. Cubic alumina of the crystallographic form {gamma}-Al{sub 2}O{sub 3} was identified by electron diffraction.

  5. Silver (Ag) Transport Mechanisms in TRISO coated particles: A Critical Review

    SciTech Connect

    I J van Rooyen; J H Neethling; J A A Engelbrecht; P M van Rooyen; G Strydom

    2012-10-01

    Transport of 110mAg in the intact SiC layer of TRISO coated particles has been studied for approximately 30 years without arriving at a satisfactory explanation of the transport mechanism. In this paper the possible mechanisms postulated in previous experimental studies, both in-reactor and out-of reactor research environment studies are critically reviewed and of particular interest are relevance to very high temperature gas reactor operating and accident conditions. Among the factors thought to influence Ag transport are grain boundary stoichiometry, SiC grain size and shape, the presence of free silicon, nano-cracks, thermal decomposition, palladium attack, transmutation products, layer thinning and coated particle shape. Additionally new insight to nature and location of fission products has been gained via recent post irradiation electron microscopy examination of TRISO coated particles from the DOE’s fuel development program. The combined effect of critical review and new analyses indicates a direction for investigating possible the Ag transport mechanism including the confidence level with which these mechanisms may be experimentally verified.

  6. Silver (Ag) Transport Mechanisms in TRISO Coated Particles: A Critical Review

    SciTech Connect

    IJ van Rooyen; ML Dunzik-Gougar; PM van Rooyen

    2014-05-01

    Transport of 110mAg in the intact SiC layer of TRISO coated particles has been studied for approximately 30 years without arriving at a satisfactory explanation of the transport mechanism. In this paper the possible mechanisms postulated in previous experimental studies, both in-reactor and out-of reactor research environment studies are critically reviewed and of particular interest are relevance to very high temperature gas reactor operating and accident conditions. Among the factors thought to influence Ag transport are grain boundary stoichiometry, SiC grain size and shape, the presence of free silicon, nano-cracks, thermal decomposition, palladium attack, transmutation products, layer thinning and coated particle shape. Additionally new insight to nature and location of fission products has been gained via recent post irradiation electron microscopy examination of TRISO coated particles from the DOE’s fuel development program. The combined effect of critical review and new analyses indicates a direction for investigating possible the Ag transport mechanism including the confidence level with which these mechanisms may be experimentally verified.

  7. Application of TiC reinforced Fe-based coatings by means of High Velocity Air Fuel Spraying

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Knoch, M. A.; Liao, X.; Sommer, J.

    2017-03-01

    In the field of hydraulic applications, different development trends can cause problems for coatings currently used as wear and corrosion protection for piston rods. Aqueous hydraulic fluids and rising raw material prices necessitate the search for alternatives to conventional coatings like galvanic hard chrome or High Velocity Oxygen Fuel (HVOF)-sprayed WC/Co coatings. In a previous study, Fe/TiC coatings sprayed by a HVOF-process, were identified to be promising coating systems for wear and corrosion protection in hydraulic systems. In this feasibility study, the novel High Velocity Air Fuel (HVAF)-process, a modification of the HVOF-process, is investigated using the same feedstock material, which means the powder is not optimized for the HVAF-process. The asserted benefits of the HVAF-process are higher particle velocities and lower process temperatures, which can result in a lower porosity and oxidation of the coating. Further benefits of the HVAF process are claimed to be lower process costs and higher deposition rates. In this study, the focus is set on to the applicability of Fe/TiC coatings by HVAF in general. The Fe/TiC HVAF coating could be produced, successfully. The HVAF- and HVOF-coatings, produced with the same powder, were investigated using micro-hardness, porosity, wear and corrosion tests. A similar wear coefficient and micro-hardness for both processes could be achieved. Furthermore the propane/hydrogen proportion of the HVAF process and its influence on the coating thickness and the porosity was investigated.

  8. Chemical thermodynamics of iodine species in the HTGR fuel particle

    SciTech Connect

    Lindemer, T.B.

    1982-09-01

    The iodine-containing species in an intact fuel particle in the high-temperature gas-cooled reactor (HTGR) have been calculated. Assumptions include: (1) attainment of chemical thermodynamic equilibrium among all species in the open porosity of the particle, primarily in the buffer layer; and (2) fission-product concentrations in proportion to their yields. The primary gaseous species is calculated to be cesium iodide; in carbide-containing fuels, gaseous barium iodide may exhibit equivalent pressures. The condensed iodine-containing phase is usually cesium iodide, but in carbide-containing fuels, barium iodide may be stable instead. Absorption of elemental iodine on the carbon in the particle appears to be less than or equal to 10/sup -4/ ..mu..g I/g C. The fission-product-spectra excess of cesium over iodine would generally be adsorbed on the carbon, but may form Cs/sub 2/MoO/sub 4/ under some circumstances.

  9. Laser dispersion and ignition of metal fuel particles.

    PubMed

    Abdel-Hafez, Ahmed A; Brodt, Matthew W; Carney, Joel R; Lightstone, James M

    2011-06-01

    The development of a laser-shock technique for dispersing Al metal fuel particles at velocities approaching those expected in a detonating explosive is discussed. The technique is described in detail by quantifying how air drag affects the temporal variation of the velocity of the dispersed particle plume. The effect of particle size is incorporated by examining various poly-dispersed commercial Al powders at different dispersion velocities (390-630 m/s). The technique is finally tested within a preliminary study of particle ignition delay and burn time, where the effect of velocity is highlighted for different particle sizes. It was found that plume velocity exhibits a modified exponential temporal profile, where smaller particles are more susceptible to air drag than larger ones. Moreover, larger particles exhibit longer ignition delays and burn times than smaller ones. The velocity of a particle was found to significantly affect its ignition delay, burn time, and combustion temperature, especially for particles in the diffusion-controlled regime. Shorter ignition delays and burn times and lower temperatures were observed at higher particle velocities. The utility of this technique as a combustion screening test for future, novel fuels is discussed.

  10. Uniform particles of pure and silica-coated cholesterol.

    PubMed

    Uskoković, Vuk; Matijević, Egon

    2007-11-15

    Uniform crystalline colloidal cholesterol particles of narrow size distribution were obtained by precipitation. The method consisted of adding a miscible non-solvent (water) into cholesterol solutions of different alcohols and acetone, without any additives. The properties of the resulting particles depended in a sensitive way on the concentration of all reactants, temperature, pH, ionic strength, and aging time. The major observed effects were due to the solubility of cholesterol, which was strongly affected by the solvent mixture and temperature. Precipitation in 1-propanol/water system yielded stable dispersions of well-defined particles, which were used to evaluate the effects of different experimental parameters on their properties. Aging of stable dispersions resulted in multi-layered aggregation of the primary platelets, the degree and rate of which process was strongly affected by temperature. Finally, it was shown that the colloidal cholesterol particles could be coated with homogeneous silica layers in order to alter their surface characteristics.

  11. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

    PubMed Central

    Latka, Leszek; Goryachev, Sergey B.; Kozerski, Stefan; Pawlowski, Lech

    2010-01-01

    Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2, depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension plasma spraying. The

  12. Resuspension of coarse fuel hot particles in the Chernobyl area.

    PubMed

    Wagenpfeil, F; Tschiersch, J

    2001-01-01

    Measurements of resuspended aerosol in the Chernobyl 30-km exclusion zone have shown coarse fuel hot particles in the activity range 1-12 Bq 137Cs per particle. The particles were sampled with newly designed rotating arm impactors which simultaneously collect during the same experiment three samples with fuel particles in the size ranges larger than 3 microns, larger than 6 microns and larger than 9 microns in geometric diameter. The radionuclide ratios, determined after gamma-spectrometry, were in good agreement with the theoretical calculations for the radionuclide-composition of the Chernobyl Nuclear Power Plant at the moment of the accident and the measured hot particles in soil in the early years after the accident. The number concentrations of airborne hot particles were derived from digital autoradiography. For wind resuspension, maximal concentrations of 2.6 coarse hot particles per 1000 m3 and during agricultural activities 36 coarse hot particles per 1000 m3 were measured. The geometric diameter of single hot particles was estimated to be between 6 and 12 microns.

  13. Tribological behavior of near-frictionless carbon coatings in high- and low-sulfur diesel fuels.

    SciTech Connect

    Alzoubi, M. F.; Ajayi, O. O.; Eryilmaz, O. L.; Ozturk, O.; Erdemir, A.; Fenske, G.

    2000-01-19

    The sulfur content in diesel fuel has a significant effect on diesel engine emissions, which are currently subject to environmental regulations. It has been observed that engine particulate and gaseous emissions are directly proportional to fuel sulfur content. With the introduction of low-sulfur fuels, significant reductions in emissions are expected. The process of sulfur reduction in petroleum-based diesel fuels also reduces the lubricity of the fuel, resulting in premature failure of fuel injectors. Thus, another means of preventing injector failures is needed for engines operating with low-sulfur diesel fuels. In this study, the authors evaluated a near-frictionless carbon (NFC) coating (developed at Argonne National Laboratory) as a possible solution to the problems associated with fuel injector failures in low-lubricity fuels. Tribological tests were conducted with NFC-coated and uncoated H13 and 52100 steels lubricated with high- and low- sulfur diesel fuels in a high-frequency reciprocating test machine. The test results showed that the NFC coatings reduced wear rates by a factor of 10 over those of uncoated steel surfaces. In low-sulfur diesel fuel, the reduction in wear rate was even greater (i.e., by a factor of 12 compared to that of uncoated test pairs), indicating that the NFC coating holds promise as a potential solution to wear problems associated with the use of low-lubricity diesel fuels.

  14. Encapsulation of TRISO particle fuel in durable soda-lime-silicate glasses

    NASA Astrophysics Data System (ADS)

    Heath, Paul G.; Corkhill, Claire L.; Stennett, Martin C.; Hand, Russell J.; Meyer, Willem C. H. M.; Hyatt, Neil C.

    2013-05-01

    Tri-Structural Isotropic (TRISO) coated particle-fuel is a key component in designs for future high temperature nuclear reactors. This study investigated the suitability of three soda lime silicate glass compositions, for the encapsulation of simulant TRISO particle fuel. A cold press and sinter (CPS) methodology was employed to produce TRISO particle-glass composites. Composites produced were determined to have an aqueous durability, fracture toughness and Vickers' hardness comparable to glasses currently employed for the disposal of high level nuclear wastes. Sintering at 700 °C for 30 min was found to remove all interconnected porosity from the composite bodies and oxidation of the outer pyrolytic carbon layer during sintering was prevented by processing under a 5% H2/N2 atmosphere. However, the outer pyrolytic carbon layer was not effectively wetted by the encapsulating glass matrix. The aqueous durability of the TRISO particle-glass composites was investigated using PCT and MCC-1 tests combined with geochemical modelling. It was found that durability was dependent on silicate and calcium solution saturation. This study provides significant advancements in the preparation of TRISO particle encapsulant waste forms. The potential for the use of non-borosilicate sintered glass composites for TRISO particle encapsulation has been confirmed, although further refinements are required.

  15. Particle emissions from ships: dependence on fuel type.

    PubMed

    Winnes, Hulda; Fridell, Erik

    2009-12-01

    This paper presents the results of field emission measurements that have been carried out on the 4500-kW four-stroke main engine on-board a product tanker. Two fuel qualities--heavy fuel oil (HFO) and marine gas oil (MGO)-have been tested on the same engine for comparable load settings. A fuel switch within the marine sector is approaching and the aim of this study is to draw initial conclusions on the subsequent effects on ship exhaust gas composition and emission factors with a focus on particles. Measurements on exhaust gas concentrations of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), total hydrocarbons (HCs), and particulate matter (PM) were conducted. The gases, except SO2, did not show any major differences between the fuels. Specific PM emissions were generally higher for HFO than for MGO; however, for the smallest size-fraction measured containing particles 0.30-0.40 microm in diameter, the opposite is observed. This finding emphasizes that to minimize negative health effects of particles from ships, further regulation may be needed to reduce small-sized particles; a fuel shift to low sulfur fuel alone does not seem to accomplish this reduction. The average of this and previously published data from on-board studies on particle emissions from ships results in emissions factors of 0.33 and 1.34 g/kWh for marine distillate oil (MDO) and HFO, respectively. Accounting for 1 standard deviation in each direction from the average values gives a range of 0.18-0.48 g/kWh for MDO and 0.56-2.12 g/kWh for HFO.

  16. Progress in Solving the Elusive Ag Transport Mechanism in TRISO Coated Particles: What is new?

    SciTech Connect

    Isabella Van Rooyen

    2014-10-01

    The TRISO particle for HTRs has been developed to an advanced state where the coating withstands internal gas pressures and retains fission products during irradiation and under postulated accidents. However, one exception is Ag that has been found to be released from high quality TRISO coated particles when irradiated and can also during high temperature accident heating tests. Although out- of- pile laboratory tests have never hither to been able to demonstrate a diffusion process of Ag in SiC, effective diffusion coefficients have been derived to successfully reproduce measured Ag-110m releases from irradiated HTR fuel elements, compacts and TRISO particles It was found that silver transport through SiC does not proceed via bulk volume diffusion. Presently grain boundary diffusion that may be irradiation enhanced either by neutron bombardment or by the presence of fission products such as Pd, are being investigated. Recent studies of irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), transmission kukuchi diffraction (TKD) patterns and high resolution transmission electron microscopy (HRTEM) have been used to further the understanding of Ag transport through TRISO particles. No silver was observed in SiC grains, but Ag was identified at triple-points and grain boundaries of the SiC layer in the TRISO particle. Cadmium was also found in some of the very same triple junctions, but this could be related to silver behavior as Ag-110m decays to Cd-110. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries and in most SiC grain boundaries and the potential role of Pd in the transport of Ag will be discussed.

  17. Underwater Coatings Testing for INEEL Fuel Basin Applications

    SciTech Connect

    Julia L. Tripp

    2004-01-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature.

  18. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    SciTech Connect

    Panda, Biswajit Goyal, P. S.

    2015-06-24

    Magnetic nano particles of Fe{sub 3}O{sub 4} coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe{sup 2+} and Fe{sup 3+} ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe{sub 3}O{sub 4} having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe{sub 3}O{sub 4} particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe{sub 3}O{sub 4} particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm.

  19. Pre- and post-irradiation characterization and properties measurements of ZrC coated surrogate TRISO particles

    SciTech Connect

    Vasudevamurthy, Gokul; Katoh, Yutai; Hunn, John D; Snead, Lance Lewis

    2010-09-01

    Zirconium carbide is a candidate to either replace or supplement silicon carbide as a coating material in TRISO fuel particles for high temperature gas-cooled reactor fuels. Six sets of ZrC coated surrogate microsphere samples, fabricated by the Japan Atomic Energy Agency using the fluidized bed chemical vapor deposition method, were irradiated in the High Flux Isotope Reactor at the Oak Ridge National Laboratory. These developmental samples available for the irradiation experiment were in conditions of either as-fabricated coated particles or particles that had been heat-treated to simulate the fuel compacting process. Five sets of samples were composed of nominally stoichiometric compositions, with the sixth being richer in carbon (C/Zr = 1.4). The samples were irradiated at 800 and 1250 C with fast neutron fluences of 2 and 6 dpa. Post-irradiation, the samples were retrieved from the irradiation capsules followed by microstructural examination performed at the Oak Ridge National Laboratory's Low Activation Materials Development and Analysis Laboratory. This work was supported by the US Department of Energy Office of Nuclear Energy's Advanced Gas Reactor program as part of International Nuclear Energy Research Initiative collaboration with Japan. This report includes progress from that INERI collaboration, as well as results of some follow-up examination of the irradiated specimens. Post-irradiation examination items included microstructural characterization, and nanoindentation hardness/modulus measurements. The examinations revealed grain size enhancement and softening as the primary effects of both heat-treatment and irradiation in stoichiometric ZrC with a non-layered, homogeneous grain structure, raising serious concerns on the mechanical suitability of these particular developmental coatings as a replacement for SiC in TRISO fuel. Samples with either free carbon or carbon-rich layers dispersed in the ZrC coatings experienced negligible grain size

  20. Light Obscuration Particle Counter Fuel Contamination Limits

    DTIC Science & Technology

    2015-10-08

    contamination. Based on this work the Department of Defense Tri-Service Petroleum , Oil and Lubricants Technical Steering Committee has recommended...Lubricants, and Related Products and Field Manual No. 10-67-2, Department of the Army Manual for Petroleum Laboratory Testing and Operations...detection of free water. APPROACH The particle counter limit evaluation took place at TARDEC’s Army Petroleum Laboratory (APL) in New

  1. Growth of the interaction layer around fuel particles in dispersion fuel

    NASA Astrophysics Data System (ADS)

    Olander, D.

    2009-01-01

    Corrosion of uranium particles in dispersion fuel by the aluminum matrix produces interaction layers (an intermetallic-compound corrosion product) around the shrinking fuel spheres. The rate of this process was modeled as series resistances due to Al diffusion through the interaction layer and reaction of aluminum with uranium in the fuel particle to produce UAl x. The overall kinetics are governed by the relative rates of these two steps, the slowest of which is reaction at the interface between Al in the interaction layer and U in the fuel particle. The substantial volume change as uranium is transferred from the fuel to the interaction layer was accounted for. The model was compared to literature data on in-reactor growth of the interaction layer and the Al/U gradient in this layer, the latter measured in ex-reactor experiments. The rate constant of the Al-U interface reaction and the diffusivity of Al in the interaction layer were obtained from this fitting procedure. The second feature of the corrosion process is the transfer of fission products from the fuel particle to the interaction layer due to the reaction. It is commonly assumed that the observed swelling of irradiated fuel elements of this type is due to release of fission gas in the interaction layer to form large bubbles. This hypothesis was tested by using the model to compute the quantity of fission gas available from this source and comparing the pressure of the resulting gas with the observed swelling of fuel plates. It was determined that the gas pressure so generated is too small to account for the observed delamination of the fuel.

  2. Solid Hydrogen Particles and Flow Rates Analyzed for Atomic Fuels

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2003-01-01

    The experiments were conducted at Glenn's Small Multipurpose Research Facility (SMIRF, ref. 5). The experimental setup was placed in the facility's vacuum tank to prevent heat leaks and subsequent boiloff of the liquid helium. Supporting systems maintained the temperature and pressure of the liquid helium bath where the solid particles were created. Solid hydrogen particle formation was tested from February 23 to April 2, 2001. Millimeter-sized solid-hydrogen particles were formed in a Dewar of liquid helium as a prelude to creating atomic fuels and propellants for aerospace vehicles. Atomic fuels or propellants are created when atomic boron, carbon, or hydrogen is stored in solid hydrogen particles. The current testing characterized the solid hydrogen particles without the atomic species, as a first step to creating a feed system for the atomic fuels and propellants. This testing did not create atomic species, but only sought to understand the solid hydrogen particle formation and behavior in the liquid helium. In these tests, video images of the solid particle formation were recorded, and the total mass flow rate of the hydrogen was measured. The mass of hydrogen that went into the gaseous phase was also recorded using a commercially available residual gas analyzer. The temperatures, pressures, and flow rates of the liquids and gases in the test apparatus were recorded as well. Testing conducted in 1999 recorded particles as small as 2 to 5 mm in diameter. The current testing extended the testing conditions to a very cold Dewar ullage gas of about 20 to 90 K above the 4 K liquid helium. With the very cold Dewar gas, the hydrogen freezing process took on new dimensions, in some cases creating particles so small that they seemed to be microscopic, appearing as infinitesimally small scintillations on the videotaped images.

  3. Solid particle erosion mechanisms of protective coatings for aerospace applications

    NASA Astrophysics Data System (ADS)

    Bousser, Etienne

    The main objective of this PhD project is to investigate the material loss mechanisms during Solid Particle Erosion (SPE) of hard protective coatings, including nanocomposite and nanostructured systems. In addition, because of the complex nature of SPE mechanisms, rigorous testing methodologies need to be employed and the effects of all testing parameters need to be fully understood. In this PhD project, the importance of testing methodology is addressed throughout in order to effectively study the SPE mechanisms of brittle materials and coatings. In the initial stage of this thesis, we studied the effect of the addition of silicon (Si) on the microstructure, mechanical properties and, more specifically, on the SPE resistance of thick CrN-based coatings. It was found that the addition of Si significantly improved the erosion resistance and that SPE correlated with the microhardness values, i.e. the coating with the highest microhardness also had the lowest erosion rate (ER). In fact, the ERs showed a much higher dependence on the surface hardness than what has been proposed for brittle erosion mechanisms. In the first article, we study the effects of the particle properties on the SPE behavior of six brittle bulk materials using glass and alumina powders. First, we apply a robust methodology to accurately characterize the elasto-plastic and fracture properties of the studied materials. We then correlate the measured ER to materials' parameters with the help of a morphological study and an analysis of the quasi-static elasto-plastic erosion models. Finally, in order to understand the effects of impact on the particles themselves and to support the energy dissipation-based model proposed here, we study the particle size distributions of the powders before and after erosion testing. It is shown that tests using both powders lead to a material loss mechanism related to lateral fracture, that the higher than predicted velocity exponents point towards a velocity

  4. Micromorphological characterization of zinc/silver particle composite coatings

    PubMed Central

    Méndez, Alia; Reyes, Yolanda; Trejo, Gabriel; StĘpień, Krzysztof

    2015-01-01

    ABSTRACT The aim of this study was to evaluate the three‐dimensional (3D) surface micromorphology of zinc/silver particles (Zn/AgPs) composite coatings with antibacterial activity prepared using an electrodeposition technique. These 3D nanostructures were investigated over square areas of 5 μm × 5 μm by atomic force microscopy (AFM), fractal, and wavelet analysis. The fractal analysis of 3D surface roughness revealed that (Zn/AgPs) composite coatings have fractal geometry. Triangulation method, based on the linear interpolation type, applied for AFM data was employed in order to characterise the surfaces topographically (in amplitude, spatial distribution and pattern of surface characteristics). The surface fractal dimension D f, as well as height values distribution have been determined for the 3D nanostructure surfaces. Microsc. Res. Tech. 78:1082–1089, 2015. © 2015 The Authors published by Wiley Periodicals, Inc. PMID:26500164

  5. Micromorphological characterization of zinc/silver particle composite coatings.

    PubMed

    Méndez, Alia; Reyes, Yolanda; Trejo, Gabriel; StĘpień, Krzysztof; Ţălu, Ştefan

    2015-12-01

    The aim of this study was to evaluate the three-dimensional (3D) surface micromorphology of zinc/silver particles (Zn/AgPs) composite coatings with antibacterial activity prepared using an electrodeposition technique. These 3D nanostructures were investigated over square areas of 5 μm × 5 μm by atomic force microscopy (AFM), fractal, and wavelet analysis. The fractal analysis of 3D surface roughness revealed that (Zn/AgPs) composite coatings have fractal geometry. Triangulation method, based on the linear interpolation type, applied for AFM data was employed in order to characterise the surfaces topographically (in amplitude, spatial distribution and pattern of surface characteristics). The surface fractal dimension Df , as well as height values distribution have been determined for the 3D nanostructure surfaces.

  6. Mechanical Particle Coating Using Polymethacrylate Nanoparticle Agglomerates for the Preparation of Controlled Release Fine Particles: the Relationship between Coating Performance and the Characteristics of Various Polymethacrylates.

    PubMed

    Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

    2017-09-09

    We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (<100μm). Second, five polymethacrylate latexes were powdered by spray freeze drying to produce colloidal agglomerates. Finally, mechanical particle coating was performed by mixing theophylline spheres and polymethacrylate agglomerates using the processor. The agglomerates were broken under mechanical stress to coat the spheres effectively. The coating performance of polymethacrylate agglomerates tended to increase as their pulverization progressed. Differences in the grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (Tg) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches Tg of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the Tg. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Induction plasma calcining of pigment particles for thermal control coatings

    NASA Technical Reports Server (NTRS)

    Farley, E. P.

    1971-01-01

    Induction plasma heating techniques were studied for calcining zinc orthotitanate particles for use in thermal control coatings. Previous studies indicated that the optimum calcining temperature is between 1400 and 1750 C. An intermediate temperature (1670 C) was chosen as a reference point for running a temperature series at the reference point and 220 C on both sides. The effect of varying chamber temperature on the reflectance spectra, before and after vacuum UV irradiation, is presented. The correlation between Zn2Ti04 paramagnetic resonance activity and its susceptibility to vacuum UV damage is discussed.

  8. Polymer latex particles: Preparation, characterization, and coating patterns

    SciTech Connect

    Wang, Leeyih.

    1993-01-01

    The coating patterns of polystyrene latex after spin drying have been intensively investigated. The model microsphere was prepared using emulsifier-free emulsion polymerization. The resulting polystyrene latex was 0.54 [mu]m in diameter with the polydispersity of 1.02. The mobility of latex spheres in concentrated dispersions was studied by diffusing wave spectroscopy (DWS). The diffusion coefficient of the polystyrene spheres dispersed in water decreased as the concentration of latex particles increased. The concentration dependence of the diffusion coefficient of this latex determined by DWS matched closely to the short-time diffusion of poly(methyl methacrylate) latex in a mixed organic fluid determined by PCS using the refractive index matching method. It indicates that the electrical repulsive force between particles in this system has a small effect on the short-time mobility of particles. This result was also confirmed by the diffusion coefficients of polystyrene spheres dispersed in water with the addition of sodium chloride, or dispersed in NMF. The presence of surfactants, SDS and C12E5, in the dispersed medium led to a great reduction on the diffusivity of latex spheres. A two dimensional ordered array of particles can be obtained from the spin drying of polystyrene latex by adding surfactants in a suitable concentration range or by choosing an appropriate substrate and/or dispersing fluid. A mechanism for the formation of hexagonally packed particles was proposed as the actions of three factors: retractive, frictional, and capillary forces.

  9. Effect of Spray Particle Velocity on Cavitation Erosion Resistance Characteristics of HVOF and HVAF Processed 86WC-10Co4Cr Hydro Turbine Coatings

    NASA Astrophysics Data System (ADS)

    Kumar, R. K.; Kamaraj, M.; Seetharamu, S.; Pramod, T.; Sampathkumaran, P.

    2016-08-01

    The hydro plants utilizing silt-laden water for power generation suffer from severe metal wastage due to particle-induced erosion and cavitation. High-velocity oxy-fuel process (HVOF)-based coatings is widely applied to improve the erosion life. The process parameters such as particle velocity, size, powder feed rate, temperature, affect their mechanical properties. The high-velocity air fuel (HVAF) technology, with higher particle velocities and lower spray temperatures, gives dense and substantially nonoxidized coating. In the present study, the cavitation resistance of 86WC-10Co4Cr-type HVOF coating processed at 680 m/s spray particle velocity was compared with HVAF coatings made at 895, 960, and 1010 m/s. The properties such as porosity, hardness, indentation toughness, and cavitation resistance were investigated. The surface damage morphology has been analyzed in SEM. The cohesion between different layers has been examined qualitatively through scratch depth measurements across the cross section. The HVAF coatings have shown a lower porosity, higher hardness, and superior cavitation resistance. Delamination, extensive cracking of the matrix interface, and detachment of the WC grains were observed in HVOF coating. The rate of metal loss is low in HVAF coatings implying that process parameters play a vital role in achieving improved cavitation resistance.

  10. Water interaction with laboratory-simulated fossil fuel combustion particles.

    PubMed

    Popovicheva, O B; Kireeva, E D; Shonija, N K; Khokhlova, T D

    2009-10-01

    To clarify the impact of fossil fuel combustion particles' composition on their capacity to take up water, we apply a laboratory approach in which the method of deposition of compounds, identified in the particulate coverage of diesel and aircraft engine soot particles, is developed. It is found that near-monolayer organic/inorganic coverage of the soot particles may be represented by three groups of fossil fuel combustion-derived particulate matter with respect to their Hansh's coefficients related to hydrophilic properties. Water adsorption measurements show that nonpolar organics (aliphatic and aromatic hydrocarbons) lead to hydrophobization of the soot surface. Acidic properties of organic compounds such as those of oxidized PAHs, ethers, ketones, aromatic, and aliphatic acids are related to higher water uptake, whereas inorganic acids and ionic compounds such as salts of organic acids are shown to be responsible for soot hydrophilization. This finding allows us to quantify the role of the chemical identity of soot surface compounds in water uptake and the water interaction with fossil fuel combustion particles in the humid atmosphere.

  11. Microbial Penetration and Utilization of Organic Aircraft Fuel-Tank Coatings1

    PubMed Central

    Crum, M. G.; Reynolds, R. J.; Hedrick, H. G.

    1967-01-01

    Microorganisms have been found as contaminants in various types of aircraft fuel tanks. Their presence introduces problems in the operation of the aircraft, including destruction of components such as the organic coatings used as protective linings in the fuel tanks. Microbial penetration and utilization of the currently used organic coatings, EC 776, DV 1180, PR 1560, and DeSoto 1080, were determined by changes in electrical resistances of the coatings; mycelial weight changes; growth counts of the bacteria; and manometric determinations on Pseudomonas aeruginosa (GD-FW B-25) and Cladosporium resinae (QMC-7998). The results indicate EC 776 and DV 1180 to be less resistant to microbial degradation than the other coatings. Organic coatings, serving as a source of nutrition, would be conducive to population buildups in aircraft fuel tanks. Images Fig. 1 PMID:16349744

  12. Method of producing carbon coated nano- and micron-scale particles

    DOEpatents

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  13. Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

    NASA Astrophysics Data System (ADS)

    Kim, Ki Hwan; Lee, Chong Tak; Lee, Chan Bock; Fielding, R. S.; Kennedy, J. R.

    2013-10-01

    Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 °C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 °C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U-20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.

  14. Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

    SciTech Connect

    K.H. Kim; C.T. Lee; C.B. Lee; R.S. Fielding; J.R. Kennedy

    2013-10-01

    Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 degrees C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 degrees C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U–20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.

  15. Particle Size Control of Polyethylene Glycol Coated Fe Nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivasan, B.; Bonder, M. J.; Zhang, Y.; Gallo, D.; Hadjipanayis, G. C.

    2006-03-01

    Recent interest in Fe nanoparticles with high magnetization is driven by their potential use in biomedical applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia treatment of cancer. This study looks at the use of a polyethylene glycol (PEG) solution to mediate the particle size and therefore control the coercivity of the resulting nanoparticles. Iron nanoparticles were synthesized using an aqueous sodium borohydride reduction of ferrous chloride by a simultaneous introduction of reagents in a Y- junction. The resulting product was collected in a vessel containing a 15 mg/ml carboxyl terminated polyethylene glycol (cPEG) in ethyl alcohol solution located under the Y junction. By varying the length of tubing below the Y junction, the particle size was varied from 5-25 nm. X-ray diffraction data indicates the presence of either amorphous Fe-B or crystalline alpha Fe, depending on the molar ratio of reagents. Magnetic measurements indicate the particles are ferromagnetic with values of coercivity ranging from 200-500 Oe and a saturation magnetization in range of 70-110 emu/g. The XRD shows that the particles are not affected by the polymer coating.

  16. Coated magnetic particles in electrochemical systems: Synthesis, modified electrodes, alkaline batteries, and paste electrodes

    NASA Astrophysics Data System (ADS)

    Unlu, Murat

    Magnetic field effects on electrochemical reactions have been studied and shown to influence kinetics and dynamics. Recently, our group has introduced a novel method to establish magnetic field effects by incorporating inert, magnetic microparticles onto the electrode structure. This modification improved several electrochemical systems including modified electrodes, alkaline batteries, and fuel cells. This dissertation describes the applicability of magnetic microparticles and the understanding of magnetic field effects in modified electrodes, alkaline batteries, and paste electrodes. Magnetic effects are studied on electrodes that are coated with an ion exchange polymer that embeds chemically inert, commercial, magnetic microparticles. The flux (electrolysis current) of redox probe to the magnetically modified system is compared to a similar non-magnetic electrode. Flux enhancements of 60% are achieved at magnetically modified electrode as compared to non-magnetic controls. In addition to modifying electrode surfaces, the incorporation of magnetic microparticles into the electrode material itself establishes a 20% increase in flux. Possible magnetic field effects are evaluated. Study of samarium cobalt modified electrolytic manganese dioxide, EMD electrodes further establish a magnetic effect on alkaline cathode performance. Magnetic modification improves alkaline battery performance in primary and secondary applications. The reaction mechanism is examined through voltammetric methods. This work also includes coating protocols to produce inert magnetic microparticles with high magnetic content. Magnetite powders are encapsulated in a polymer matrix by dispersion polymerization. Composite particles are examined in proton exchange membrane fuel cells to study carbon monoxide tolerance.

  17. Very high flux research reactors based on particle fuels

    SciTech Connect

    Powell, J.R.; Takahashi, H.

    1985-01-01

    A new approach to high flux research reactors is described, the VHFR (Very High Flux Reactor). The VHFR fuel region(s) are packed beds of HTGR-type fuel particles through which coolant (e.g., D/sub 2/O) flows directly. The small particle diameter (typically on the order of 500 microns) results in very large surface areas for heat transfer (approx. 100 cm/sup 2//cm/sup 3/ of bed), high power densities (approx. 10 megawatts per liter), and minimal ..delta..T between fuel and coolant (approx. 10 K) VHFR designs are presented which achieve steady-state fluxes of approx. 2x10/sup 16/ n/cm/sup 2/sec. Deuterium/beryllium combinations give the highest flux levels. Critical mass is low, approx. 2 kg /sup 235/U for 20% enriched fuel. Refueling can be carried out continuously on-line, or in a batch process with a short daily shutdown. Fission product inventory is very low, approx. 100 to 300 grams, depending on design.

  18. Electroless Ni-Cu-P/nano-graphite composite coatings for bipolar plates of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Lee, Cheng-Kuo

    2012-12-01

    This study evaluates the effects of an electroless Ni-Cu-P/nano-graphite composite coating on the surface characteristics of anodized 5083 aluminum alloy, including electrical resistivity, corrosion resistance of the alloy in a simulated solution of 0.5 M H2SO4 + 2 ppm NaF in polymer electrolyte membrane fuel cells (PEMFCs). The co-deposition and adhesion of the composite coatings on a 5083 substrate are enhanced by an anodizing process. The electroless Ni-Cu-P plating solution is prepared by adding different CuSO4·5H2O concentrations into the electroless Ni-P plating solution and adding nano-graphite (15-40 nm) particles to form the Ni-Cu-P/nano-graphite composite coatings. Experimental results indicate that the electroless Ni-Cu-P/nano-graphite composite coating enhances the hardness, conductivity, corrosion resistance of the 5083 substrate in the corrosive solution. The anodizing treatment enhances the electroless composite coatings by providing better uniformity, density, and adhesion compared to substrate without anodizing treatment. The electroless Ni-Cu-P/nano-graphite composite coating deposited on the optimal anodized 5083 substrate at a low CuSO4·5H2O concentration of 0.25 g l-1 with 20 g l-1 nano-graphite added have the best surface structure, highest hardness, electrical conductivity and corrosion resistance. Therefore, this novel electroless Ni-Cu-P/nano-graphite composite-coated 5083 aluminum alloy has potential applications in bipolar plates of PEM fuel cells.

  19. Numerical simulation of white double-layer coating with different submicron particles on the spectral reflectance

    NASA Astrophysics Data System (ADS)

    Chai, Jiale; Cheng, Qiang; Si, Mengting; Su, Yang; Zhou, Yifan; Song, Jinlin

    2017-03-01

    The spectral selective coating is becoming more and more popular against solar irradiation not only in keeping the coated objects stay cool but also retain the appearance of the objects by reducing the glare of reflected sunlight. In this work a numerical study is investigated to design the double-layer coating with different submicron particles to achieve better performance both in thermal and aesthetic aspects. By comparison, the performance of double-layer coating with TiO2 and ZnO particles is better than that with single particles. What's more, the particle diameter, volume fraction of particle as well as substrate condition is also investigated. The results show that an optimized double-layer coating with particles should be the one with an appropriate particle diameter, volume fraction and the black substrate.

  20. Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

    PubMed

    Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

    2013-09-10

    We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm.

  1. Carbon monoxide formation in UO2 kerneled HTR fuel particles containing oxygen getters

    NASA Astrophysics Data System (ADS)

    Proksch, E.; Strigl, A.; Nabielek, H.

    1986-01-01

    Mass spectrometric measurements of CO in irradiated UO2 fuel particles containing oxygen getters are summarized. Uranium carbide addition in the 3% to 15% range reduces the CO release by factors between 25 and 80, up to burn-up levels as high as 70% FIMA. Unintentional gettering by SiC in TRISO coated particles with failed inner pyrocarbon layers results in CO reduction factors between 15 and 110. For ZrC, ambiguous results are obtained; ZrC probably results in CO reduction by a factor of 40; Ce2O3 and La2O3 seem less effective than the carbides; for Ce2O3, reduction factors between 3 and 15 are found. However, the results are possibly incorrect due to premature oxidation of the getter already during fabrication. Addition of SiO2 + Al2O3 has no influence on CO release.

  2. Coating-type three-dimensional acetate-driven microbial fuel cells.

    PubMed

    Yu, Jin; Tang, Yulan

    2015-08-01

    This study uses sodium acetate as fuel to construct bioelectricity in coating-type three-dimensional microbial fuel cells anode. The coating-type three-dimensional anode was constructed using iron net as structural support, adhering a layer of carbon felt as primary coating and using carbon powder and 30% PTFE solution mixture as coating. The efficiency of electricity production and wastewater treatment were analyzed for the three-dimensional acetate-fed (C2H3NaO2) microbial fuel cells with the various ratio of the coating mixture. The results showed that the efficiency of electricity production was significantly improved when using the homemade coating-type microbial fuel cells anode compared with the one without coating on the iron net, which the apparent internal resistance was decreased by 59.4% and the maximum power density was increased by 1.5 times. It was found the electricity production was greatly influenced by the ratio of the carbon powder and PTFE in the coating. The electricity production was the highest with apparent internal resistance of 190 Ω, and maximum power density of 5189.4 mW m(-3) when 750 mg of carbon powder and 10 ml of PTFE (i.e., ratio 75:1) was used in the coating. With the efficiency of electricity production, wide distribution and low cost of the raw materials, the homemade acetate-fed microbial fuel cells provides a valuable reference to the development of the composition microbial fuel cell anode production. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  3. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  4. Electron microscopic evaluation and fission product identification of irradiated TRISO coated particles from the AGR-1 experiment: A preliminary Study

    SciTech Connect

    I J van Rooyen; D E Janney; B D Miller; J L Riesterer; P A Demkowicz

    2012-10-01

    ABSTRACT Post-irradiation examination of coated particle fuel from the AGR-1 experiment is in progress at Idaho National Laboratory and Oak Ridge National Laboratory. In this presentation a brief summary of results from characterization of microstructures in the coating layers of selected irradiated fuel particles with burnup of 11.3% and 19.3% FIMA will be given. The main objective of the characterization were to study irradiation effects, fuel kernel porosity, layer debonding, layer degradation or corrosion, fission-product precipitation, grain sizes, and transport of fission products from the kernels across the TRISO layers. Characterization techniques such as scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and wavelength dispersive spectroscopy were used. A new approach to microscopic quantification of fission-product precipitates is also briefly demonstrated. The characterization emphasized fission-product precipitates in the SiC-IPyC interface, SiC layer and the fuel-buffer interlayer, and provided significant new insights into mechanisms of fission-product transport. Although Pd-rich precipitates were identified at the SiC-IPyC interlayer, no significant SiC-layer thinning was observed for the particles investigated. Characterization of these precipitates highlighted the difficulty of measuring low concentration Ag in precipitates with significantly higher concentrations of contain Pd and U. Different approaches to resolving this problem are discussed. Possible microstructural differences between particles with high and low releases of Ag particles are also briefly discussed, and an initial hypothesis is provided to explain fission-product precipitate compositions and locations. No SiC phase transformations or debonding of the SiC-IPyC interlayer as a result of irradiation were observed. Lessons learned from the post-irradiation examination are described and future actions are recommended.

  5. Study of properties of SiC layer in TRISO coated particles grown using different alkyl-silicon compounds

    NASA Astrophysics Data System (ADS)

    Prakash, Jyoti; Ghosh, Sunil; Venugopalan, Ramani; Sathiyamoorthy, D.

    2013-06-01

    The silicon carbide (SiC) layer used for the formation of Tri-isostatic (TRISO) coated fuel particles is normally produced at high temperatures via fluidized bed chemical vapor deposition from methyltrichlorosilane (MTS) in a hydrogen environment. In this work, we show the deposition of uniform SiC layers using different organosilicon precursors such as MTS and hexamethyldisilane (HMDS) via spouted bed chemical vapor deposition. From the X-ray diffraction pattern it could be inferred that the SiC deposits obtained through different precursors have the β-SiC phase. The microstructure and mechanical properties of the fabricated SiC coating were studied. The hardness and fracture toughness of the fabricated SiC coatings using MTS and HMDS were nearly the same and close to the theoretical value for pure silicon carbide.

  6. Performance of HTGR biso- and triso-coated fertile particles irradiated in capsule HT-34

    SciTech Connect

    Long, E.L. Jr.; Tiegs, T.N.; Robbins, J.M.; Kania, M.J.

    1981-08-01

    Experiment HT-34, irradiated in the target region of the High Flux Isotope Reactor (HFIR), was designed to correlate HTGR Biso- and Triso-coated particle performance with fabrication parameters. Gamma analysis of the irradiated Triso-coated ThO/sub 2/ particles showed that the SiC deposited at the highest coating rate apparently had the best cesium-retention properties. Results of a similar analysis of the irradiated Biso-coated ThO/sub 2/ particles showed no differences in performance that could be related to coating conditions, but all the particles showed a significant loss of cesium (> 50%) at the higher temperatures. Pressure-vessel failures occurred with a significant number of particles; however, fission-gas-content measurements made at room temperature showed that the intact Biso particles from all batches except one became permeable during irradiation.

  7. Evaluation of High Velocity Oxygen Fuel (HVOF) Al/SiCp Coatings as Corrosion Control Coatings for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Taltavull, C.; Lopez, A. J.; Torres, B.; Rams, J.

    2014-06-01

    High velocity oxygen-fuel (HVOF) thermal spray technique has been used to fabricate Al and MMC (Al/SiCp) coatings on the AZ91 Mg alloy as a corrosion-control coatings. Corrosion behaviour of the coated specimens had been evaluated by electrochemical tests which revealed that some coated specimens presented an improvement on the corrosion behaviour of the AZ91 substrate. Taguchi DOE method has been used to analyse the relationship between the spraying conditions, i.e. spraying distance, % SiCp in feedstock, number of layers deposited and gun speed, and the corrosion behaviour of the coated specimens. In addition, a relationship between the coating characteristic, i.e. thickness, porosity, adhesion and roughness, and the corrosion behaviour of the coated specimens had also been studied. Optimum spraying conditions were fabricated and corrosion tested to validate the Taguchi DOE method analysis. Among the different coatings features, thickness and compactness seems to be the most relevant ones in terms of corrosion.

  8. A theoretical study on gas-phase coating of aerosol particles

    SciTech Connect

    Jain, S.; Fotou, G.P.; Kodas, T.T.

    1997-01-01

    In situ coating of aerosol particles by gas-phase and surface reaction in a flow reactor is modeled accounting for scavenging (capture of small particles by large particles) and simultaneous surface reaction along with the finite sintering rate of the scavenged particles. A log-normal size distribution is assumed for the host and coating particles to describe coagulation and a monodisperse size distribution is used for the coating particles to describe sintering. As an example, coating of titania particles with silica in a continuous flow hot-wall reactor was modeled. High temperatures, low reactant concentrations, and large host particle surface areas favored smoother coatings in the parameter range: temperature 1,700--1,800 K, host particle number concentration 1 {times} 10{sup 5}--1 {times} 10{sup 7} No./cm{sup 3}, average host particle size 1 {micro}m, inlet coating reactant concentration (SiCl{sub 4}) 2 {times} 10{sup {minus}7}--2 {times} 10{sup {minus}10} mol/cm{sup 3}, and various surface reaction rates. The fraction of silica deposited on the TiO{sub 2} particles decreased by more than seven times with a hundredfold increase in SiCl{sub 4} inlet concentration because of the resulted increase in the average SiO{sub 2} particle size under the assumed coating conditions. Increasing the TiO{sub 2} particle number concentration resulted in higher scavenging efficiency of SiO{sub 2}. In the TiO{sub 2}/SiO{sub 2} system it is likely that surface reaction as well as scavenging play important roles in the coating process. The results agree qualitatively with experimental observations of TiO{sub 2} particles coated in situ with silica.

  9. Engineered plant biomass particles coated with biological agents

    DOEpatents

    Dooley, James H.; Lanning, David N.

    2014-06-24

    Plant biomass particles coated with a biological agent such as a bacterium or seed, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

  10. Engineered plant biomass particles coated with bioactive agents

    DOEpatents

    Dooley, James H; Lanning, David N

    2013-07-30

    Plant biomass particles coated with a bioactive agent such as a fertilizer or pesticide, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

  11. Anisotropy measurement of pyrolytic carbon layers of coated particles

    SciTech Connect

    Vesyolkin, Ju. A. Ivanov, A. S.; Trushkina, T. V.

    2015-12-15

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ∼0.3%.

  12. Anisotropy measurement of pyrolytic carbon layers of coated particles

    NASA Astrophysics Data System (ADS)

    Vesyolkin, Ju. A.; Ivanov, A. S.; Trushkina, T. V.

    2015-12-01

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ~0.3%.

  13. Near-frictionless carbon coatings for use in fuel injectors and pump systems operating with low-sulfur diesel fuels

    SciTech Connect

    Erdemir, A.; Ozturk, O.; Alzoubi, M.; Woodford, J.; Ajayi, L.; Fenske, G.

    2000-01-19

    While sulfur in diesel fuels helps reduce friction and prevents wear and galling in fuel pump and injector systems, it also creates environmental pollution in the form of hazardous particulates and SO{sub 2} emissions. The environmental concern is the driving force behind industry's efforts to come up with new alternative approaches to this problem. One such approach is to replace sulfur in diesel fuels with other chemicals that would maintain the antifriction and antiwear properties provided by sulfur in diesel fuels while at the same time reducing particulate emissions. A second alternative might be to surface-treat fuel injection parts (i.e., nitriding, carburizing, or coating the surfaces) to reduce or eliminate failures associated with the use of low-sulfur diesel fuels. This research explores the potential usefulness of a near-frictionless carbon (NFC) film developed at Argonne National Laboratory in alleviating the aforementioned problems. The lubricity of various diesel fuels (i.e., high-sulfur, 500 ppm; low sulfur, 140 ppm; ultra-clean, 3 ppm; and synthetic diesel or Fischer-Tropsch, zero sulfur) were tested by using both uncoated and NFC-coated 52100 steel specimens in a ball-on-three-disks and a high-frequency reciprocating wear-test rig. The test program was expanded to include some gasoline fuels as well (i.e., regular gasoline and indolene) to further substantiate the usefulness of the NFC coatings in low-sulfur gasoline environments. The results showed that the NFC coating was extremely effective in reducing wear and providing lubricity in low-sulfur or sulfur-free diesel and gasoline fuels. Specifically, depending on the wear test rig, test pair, and test media, the NFC films were able to reduce wear rates of balls and flats by factors of 8 to 83. These remarkable reductions in wear rates raise the prospect for using the ultra slick carbon coatings to alleviate problems that will be caused by the use of low sulfur diesel and gasoline fuels. Surfaces

  14. Some parametric flow analyses of a particle bed fuel element

    SciTech Connect

    Dobranich, D.

    1993-05-01

    Parametric calculations are performed, using the SAFSIM computer program, to investigate the fluid mechanics and heat transfer performance of a particle bed fuel element. Both steady-state and transient calculations are included, addressing such issues as flow stability, reduced thrust operation, transpiration drag, coolant conductivity enhancement, flow maldistributions, decay heat removal, flow perturbations, and pulse cooling. The calculations demonstrate the dependence of the predicted results on the modeling assumptions and thus provide guidance as to where further experimental and computational investigations are needed. The calculations also demonstrate that both flow instability and flow maldistribution in the fuel element are important phenomena. Furthermore, results are encouraging that geometric design changes to the element can significantly reduce problems related to these phenomena, allowing improved performance over a wide range of element power densities and flow rates. Such design changes will help to maximize the operational efficiency of space propulsion reactors employing particle bed fuel element technology. Finally, the results demonstrate that SAFSIM is a valuable engineering tool for performing quick and inexpensive parametric simulations addressing complex flow problems.

  15. Effects of Particle Additives on Acoustically Coupled Fuel Droplet Combustion

    NASA Astrophysics Data System (ADS)

    Sim, Hyung Sub; Plascencia Quiroz, Miguel; Vargas, Andres; Bennewitz, John; Smith, Owen; Karagozian, Ann

    2016-11-01

    Addition of nanoscale particulates to liquid hydrocarbon fuels is suggested to have numerous benefits for combustion systems, although aggregation of metal nanoparticles can produce deleterious effects. The present experiments explore the effect of nano Aluminum (nAl) additives on the combustion of single liquid fuel droplets, with and without exposure of the droplets to standing acoustic waves. Building on prior studies, the present experiments quantify variations in the burning rate constant K for ethanol droplets with increasing concentrations of nAl in a quiescent environment. Burning fuel droplets that are continuously fed via a capillary as well as suspended (non-fed) droplets are examined. Nano Al is observed to create ejections of both particles and vapor toward the end of the burning period for non-fed droplets; this phenomenon is delayed when the droplet is replenished via continuous fuel delivery. Yet for the majority of conditions explored, increasing concentrations of nAl tend to reduce K. When ethanol droplets with nAl are exposed to standing waves, acoustic perturbations appear to delay particulate agglomeration, sustaining combustion for a longer period of time and increasing K. Supported by AFOSR Grant FA9550-15-1-0339.

  16. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    NASA Astrophysics Data System (ADS)

    Mohan, Arun Ram

    Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

  17. Modeling emissivity of low-emissivity coating containing horizontally oriented metallic flake particles

    NASA Astrophysics Data System (ADS)

    Chen, Shuai; Yuan, Le; Weng, Xiaolong; Deng, Longjiang

    2014-11-01

    The scattering and absorption cross sections of horizontally oriented metallic flake particles are estimated by extended geometric optics that includes diffraction and edge effects. Emissivity of the coating containing those particles is calculated using Kubelka-Munk theory. The dependence of emissivity of the coating on the radius, thickness, content of metallic flake particles and coating thickness is discussed. Finally, theoretical results are compared with the experimental measurements with Al/acrylic resin coating system and the results show that simulation values are in good agreement with experimental ones.

  18. A statistical approach to optimize the spray drying of starch particles: application to dry powder coating.

    PubMed

    Bilancetti, Luca; Poncelet, Denis; Loisel, Catherine; Mazzitelli, Stefania; Nastruzzi, Claudio

    2010-09-01

    This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency, demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value.

  19. Advanced Electron Microscopy and Micro analytical technique development and application for Irradiated TRISO Coated Particles from the AGR-1 Experiment

    SciTech Connect

    Van Rooyen, Isabella Johanna; Lillo, Thomas Martin; Wen, Haiming; Wright, Karen Elizabeth; Madden, James Wayne; Aguiar, Jeffery Andrew

    2017-01-01

    A series of up to seven irradiation experiments are planned for the Advanced Gas Reactor (AGR) Fuel Development and Quantification Program, with irradiation completed at the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for the first experiment (i.e., AGR-1) in November 2009 for an effective 620 full power days. The objective of the AGR-1 experiment was primarily to provide lessons learned on the multi-capsule test train design and to provide early data on fuel performance for use in fuel fabrication process development and post-irradiation safety testing data at high temperatures. This report describes the advanced microscopy and micro-analysis results on selected AGR-1 coated particles.

  20. Particle transport in pellet fueled JET (Jet European Torus) plasmas

    SciTech Connect

    Baylor, L.R.

    1990-01-01

    Pellet fueling experiments have been carried out on the Joint European Torus (JET) tokamak with a multi-pellet injector. The pellets are injected at speeds approaching 1400 m/s and penetrate deep into the JET plasma. Highly peaked electron density profiles are achieved when penetration of the pellets approaches or goes beyond the magnetic axis, and these peaked profiles persist for more than two seconds in ohmic discharges and over one second in ICRF heated discharges. In this dissertation, analysis of electron particle transport in multi-pellet fueled JET limiter plasmas under a variety of heating conditions is described. The analysis is carried out with a one and one-half dimensional radial particle transport code to model the experimental density evolution with various particle transport coefficients. These analyses are carried out in plasmas with ohmic heating, ICRF heating, and neural beam heating, in limiter configurations. Peaked density profile cases are generally characterized by diffusion coefficients with a central (r/a < 0.5) diffusivity {approximately}0.1 m{sup 2}/s that increases rapidly to {approximately}0.3 m{sup 2}/s at r/a = 0.6 and then increases out to the plasma edge as (r/a){sup 2}. These discharges can be satisfactorily modeled without any anomalous convective (pinch) flux. 79 refs., 60 figs.

  1. Enhancement and Prediction of Adhesion Strength of Copper Cold Spray Coatings on Steel Substrates for Nuclear Fuel Repository

    NASA Astrophysics Data System (ADS)

    Fernández, R.; MacDonald, D.; Nastić, A.; Jodoin, B.; Tieu, A.; Vijay, M.

    2016-12-01

    Thick copper coatings have been envisioned as corrosion protection barriers for steel containers used in repositories for nuclear waste fuel bundles. Due to its high deposition rate and low oxidation levels, cold spray is considered as an option to produce these coatings as an alternative to traditional machining processes to create corrosion protective sleeves. Previous investigations on the deposition of thick cold spray copper coatings using only nitrogen as process gas on carbon steel substrates have continuously resulted in coating delamination. The current work demonstrates the possibility of using an innovative surface preparation process, forced pulsed waterjet, to induce a complex substrate surface morphology that serves as anchoring points for the copper particles to mechanically adhere to the substrate. The results of this work show that, through the use of this surface preparation method, adhesion strength can be drastically increased, and thick copper coatings can be deposited using nitrogen. Through finite element analysis, it was shown that it is likely that the bonding created is purely mechanical, explaining the lack of adhesion when conventional substrate preparation methods are used and why helium is usually required as process gas.

  2. Utilizing a Segmented Fuel Cell to Study the Effects of Electrode Coating Irregularities on PEM Fuel Cell Initial Performance

    DOE PAGES

    Phillips, Adam; Ulsh, Michael; Porter, Jason; ...

    2017-04-27

    An understanding of the impact of coating irregularities on beginning of life polymer electrolyte fuel cell (PEMFC) performance is essential to develop and establish manufacturing tolerances for its components. Coating irregularities occurring in the fuel cell electrode can either possess acceptable process variations or potentially harmful defects. A segmented fuel cell (SFC) is employed to understand how 100% catalyst reduction irregularities ranging from 0.125 to 1 cm2 in the cathode electrode of a 50 cm2 sized cell impact spatial and total cell performance at dry and wet humidification conditions. Here, by analyzing the data in a differential format the localmore » performance effects of irregularity sizes down to 0.25 cm2 were detected in the current distribution of the cell. Slight total cell performance impacts, due to irregularity sizes of 0.5 and 1 cm2, were observed under dry operation and high current densities.« less

  3. Facile Preparation of a Robust and Durable Superhydrophobic Coating Using Biodegradable Lignin-Coated Cellulose Nanocrystal Particles.

    PubMed

    Huang, Jingda; Wang, Siqun; Lyu, Shaoyi

    2017-09-14

    It is a challenge for a superhydrophobic coating to overcome the poor robustness and the rough surface structure that is usually built using inorganic particles that are difficult to degrade. In this study, a robust superhydrophobic coating is facilely prepared by using commercial biodegradable lignin-coated cellulose nanocrystal (L-CNC) particles after hydrophobic modification to build rough surface structures, and by choosing two different adhesives (double-sided tape and quick-setting epoxy) to support adhesion between the L-CNC particles and the substrates. In addition to excellent self-cleaning and water repellence properties, the resulting coatings show outstanding mechanical strength and durability against sandpaper abrasion, finger-wipe, knife-scratch, water jet, UV radiation, high temperature, and acidic and alkali solutions, possessing a wide application prospect.

  4. Facile Preparation of a Robust and Durable Superhydrophobic Coating Using Biodegradable Lignin-Coated Cellulose Nanocrystal Particles

    PubMed Central

    Huang, Jingda; Lyu, Shaoyi

    2017-01-01

    It is a challenge for a superhydrophobic coating to overcome the poor robustness and the rough surface structure that is usually built using inorganic particles that are difficult to degrade. In this study, a robust superhydrophobic coating is facilely prepared by using commercial biodegradable lignin-coated cellulose nanocrystal (L-CNC) particles after hydrophobic modification to build rough surface structures, and by choosing two different adhesives (double-sided tape and quick-setting epoxy) to support adhesion between the L-CNC particles and the substrates. In addition to excellent self-cleaning and water repellence properties, the resulting coatings show outstanding mechanical strength and durability against sandpaper abrasion, finger-wipe, knife-scratch, water jet, UV radiation, high temperature, and acidic and alkali solutions, possessing a wide application prospect. PMID:28906449

  5. Comparison of the Mechanical and Electrochemical Properties of WC-25Co Coatings Obtained by High Velocity Oxy-Fuel and Cold Gas Spraying

    NASA Astrophysics Data System (ADS)

    Couto, M.; Dosta, S.; Fernández, J.; Guilemany, J. M.

    2014-12-01

    Cold gas spray (CGS) coatings were previously produced by spraying WC-25Co cermet powders onto Al7075-T6 and low-carbon steel substrates. Unlike conventional flame spray techniques (e.g., high-velocity oxy-fuel; HVOF), no melting of the powder occurs; the particles are deformed and bond together after being sprayed by a supersonic jet of compressed gas, thereby building up several layers and forming a coating. WC-Co cermets are used in wear-resistant parts, because of their combination of mechanical, physical, and chemical properties. XRD tests were previously run on the initial powder and the coatings to determine possible phase changes during spraying. The bonding strength of the coatings was measured by adhesion tests. Here, WC-25Co coatings were also deposited on the same substrates by HVOF spraying. The wear resistance and fracture toughness of the coatings obtained previously by CGS and the HVOF coatings obtained here were studied. Their corrosion resistance was determined by electrochemical measurements. It was possible to achieve thick, dense, and hard CGS coatings on Al7075-T6 and low-carbon steel substrates, with better or the same mechanical and electrochemical properties as those of the HVOF coatings; making the former a highly competitive method for producing WC-25Co coatings.

  6. Review of Rover fuel element protective coating development at Los Alamos

    NASA Technical Reports Server (NTRS)

    Wallace, Terry C.

    1991-01-01

    The Los Alamos Scientific Laboratory (LASL) entered the nuclear propulsion field in 1955 and began work on all aspects of a nuclear propulsion program with a target exhaust temperature of about 2750 K. A very extensive chemical vapor deposition coating technology for preventing catastrophic corrosion of reactor core components by the high temperature, high pressure hydrogen propellant gas was developed. Over the 17-year term of the program, more than 50,000 fuel elements were coated and evaluated. Advances in performance were achieved only through closely coupled interaction between the developing fuel element fabrication and protective coating technologies. The endurance of fuel elements in high temperature, high pressure hydrogen environment increased from several minutes at 2000 K exit gas temperature to 2 hours at 2440 K exit gas temperature in a reactor test and 10 hours at 2350 K exit gas temperature in a hot gas test. The purpose of this paper is to highlight the rationale for selection of coating materials used (NbC and ZrC), identify critical fuel element-coat interactions that had to be modified to increase system performance, and review the evolution of protective coating technology.

  7. Development of Diffusion barrier coatings and Deposition Technologies for Mitigating Fuel Cladding Chemical Interactions (FCCI)

    SciTech Connect

    Sridharan, Kumar; Allen, Todd; Cole, James

    2013-02-27

    The goal of this project is to develop diffusion barrier coatings on the inner cladding surface to mitigate fuel-cladding chemical interaction (FCCI). FCCI occurs due to thermal and radiation enhanced inter-diffusion between the cladding and fuel materials, and can have the detrimental effects of reducing the effective cladding wall thickness and lowering the melting points of the fuel and cladding. The research is aimed at the Advanced Burner Reactor (ABR), a sodium-cooled fast reactor, in which higher burn-ups will exacerbate the FCCI problem. This project will study both diffusion barrier coating materials and deposition technologies. Researchers will investigate pure vanadium, zirconium, and titanium metals, along with their respective oxides, on substrates of HT-9, T91, and oxide dispersion-strengthened (ODS) steels; these materials are leading candidates for ABR fuel cladding. To test the efficacy of the coating materials, the research team will perform high-temperature diffusion couple studies using both a prototypic metallic uranium fuel and a surrogate the rare-earth element lanthanum. Ion irradiation experiments will test the stability of the coating and the coating-cladding interface. A critical technological challenge is the ability to deposit uniform coatings on the inner surface of cladding. The team will develop a promising non-line-of-sight approach that uses nanofluids . Recent research has shown the feasibility of this simple yet novel approach to deposit coatings on test flats and inside small sections of claddings. Two approaches will be investigated: 1) modified electrophoretic deposition (MEPD) and 2) boiling nanofluids. The coatings will be evaluated in the as-deposited condition and after sintering.

  8. Particle Sizing in a Fuel-Rich Ramjet Combustor.

    DTIC Science & Technology

    1983-08-01

    COVERED Particle Sizing in a Fuel-Rich Ramjet Combustor Technical Memorandum 6 PERFORMING ORG. REPORT NUMBER 7. AIJTHORII CONTRACT OR GRANT NUMBER~s...R. Turner and R. A. Murphy N00024-83-C-S3Ol 9. PERFORMING ORGANIZATION NAME & ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK The Johns Hopkins University... Analyi , of t)op- pier Signal Characteristics for a Cross-tean I aser Doppler Ve- locimcier." 4ppI. Opt.. 14. 2177 (1975). In the present configuration

  9. Suspension High Velocity Oxy-Fuel (SHVOF)-Sprayed Alumina Coatings: Microstructure, Nanoindentation and Wear

    NASA Astrophysics Data System (ADS)

    Murray, J. W.; Ang, A. S. M.; Pala, Z.; Shaw, E. C.; Hussain, T.

    2016-12-01

    Suspension high velocity oxy-fuel spraying can be used to produce thermally sprayed coatings from powdered feedstocks too small to be processed by mechanical feeders, allowing formation of nanostructured coatings with improved density and mechanical properties. Here, alumina coatings were produced from submicron-sized feedstock in aqueous suspension, using two flame combustion parameters yielding contrasting microstructures. Both coatings were tested in dry sliding wear conditions with an alumina counterbody. The coating processed with high combustion power of 101 kW contained 74 wt.% amorphous phase and 26 wt.% crystalline phase (95 wt.% gamma and 3 wt.% alpha alumina), while the 72-kW coating contained lower 58 wt.% amorphous phase and 42 wt.% crystalline phases (73 wt.% was alpha and 26 wt.% gamma). The 101-kW coating had a dry sliding specific wear rate between 4 and 4.5 × 10-5 mm3/Nm, 2 orders of magnitude higher than the 72-kW coating wear rate of 2-4.2 × 10-7 mm3/Nm. A severe wear regime dominated by brittle fracture and grain pullout of the coating was responsible for the wear of the 101-kW coating, explained by mean fracture toughness three times lower than the 72-kW coating, owing to the almost complete absence of alpha alumina.

  10. Fabrication of polyaniline-coated Kapok (Ceiba pentandra) fibers embedded with copper-based particles

    NASA Astrophysics Data System (ADS)

    Arguelles, K. E.; Herrera, M. U.; Futalan, C. C. M.; Balela, M. D. L.

    2017-05-01

    Polyaniline-coated kapok (Ceiba pentandra) fibers that were embedded with Cu-based particles were fabricated for antimicrobial application. Kapok fibers were coated with polyaniline molecules using oxidative polymerization. The coated fibers were embedded with copper-based particles using soaking method in prepared CuO suspension. X-ray diffraction (XRD) pattern shows presence of Cu and Cu2O particles on the modified fibers. Scanning electron microscopy (SEM) supports the presence of embedded particles on the modified fibers. The samples showed antimicrobial activity against Escherichia coli and Staphylococcus aureus.

  11. Detailed Reaction Kinetics for CFD Modeling of Nuclear Fuel Pellet Coating for High Temperature Gas-Cooled Reactors

    SciTech Connect

    Battaglia, Francine

    2008-11-29

    The research project was related to the Advanced Fuel Cycle Initiative and was in direct alignment with advancing knowledge in the area of Nuclear Fuel Development related to the use of TRISO fuels for high-temperature reactors. The importance of properly coating nuclear fuel pellets received a renewed interest for the safe production of nuclear power to help meet the energy requirements of the United States. High-temperature gas-cooled nuclear reactors use fuel in the form of coated uranium particles, and it is the coating process that was of importance to this project. The coating process requires four coating layers to retain radioactive fission products from escaping into the environment. The first layer consists of porous carbon and serves as a buffer layer to attenuate the fission and accommodate the fuel kernel swelling. The second (inner) layer is of pyrocarbon and provides protection from fission products and supports the third layer, which is silicon carbide. The final (outer) layer is also pyrocarbon and provides a bonding surface and protective barrier for the entire pellet. The coating procedures for the silicon carbide and the outer pyrocarbon layers require knowledge of the detailed kinetics of the reaction processes in the gas phase and at the surfaces where the particles interact with the reactor walls. The intent of this project was to acquire detailed information on the reaction kinetics for the chemical vapor deposition (CVD) of carbon and silicon carbine on uranium fuel pellets, including the location of transition state structures, evaluation of the associated activation energies, and the use of these activation energies in the prediction of reaction rate constants. After the detailed reaction kinetics were determined, the reactions were implemented and tested in a computational fluid dynamics model, MFIX. The intention was to find a reduced mechanism set to reduce the computational time for a simulation, while still providing accurate results

  12. Kinetics of fuel particle weathering and 90Sr mobility in the Chernobyl 30-km exclusion zone.

    PubMed

    Kashparov, V A; Oughton, D H; Zvarich, S I; Protsak, V P; Levchuk, S E

    1999-03-01

    Weathering of fuel particles and the subsequent leaching of radionuclides causes 90Sr mobility in Chernobyl soils to increase with time after deposition. Studies of 90Sr speciation in soils collected in 1995 and 1996 from the Chernobyl 30-km exclusion zone have been used to calculate rates of fuel particles dissolution under natural environmental conditions. Results show that the velocity of fuel particle dissolution is primarily dependent on the physico-chemical characteristics of the particles and partially dependent on soil acidity. Compared to other areas, the fuel particle dissolution rate is significantly lower in the contaminated areas to the west of the Chernobyl reactor where deposited particles were presumably not oxidized prior to release. The data have been used to derive mathematical models that describe the rate of radionuclide leaching from fuel particles in the exclusion zone and changes in soil-to-plant transfer as a function of particle type and soil pH.

  13. Synthesis and Corrosion Study of Zirconia-Coated Carbonyl Iron Particles

    SciTech Connect

    Shen, R.; Shafrir, S.N.; Miao, C.; Wang, M.; Lambropoulos, J.C.; Jacobs, S.D.; Yang, H.

    2010-01-07

    This paper describes the surface modification of micrometer-sized magnetic carbonyl iron particles (CI) with zirconia from zirconium(IV) butoxide using a sol–gel method. Zirconia shells with various thicknesses and different grain sizes and shapes are coated on the surface of CI particles by changing the reaction conditions, such as the amounts of zirconia sol, nitric acid, and CI particles. A silica adhesive layer made from 3-aminopropyl trimethoxysilane (APTMS) can be introduced first onto the surface of CI particles in order to adjust both the size and the shape of zirconia crystals, and thus the roughness of the coating. The microanalyses on these coated particles are studied by field-emission scanning electron microscopy (FE-SEM) and X-ray-diffraction (XRD). Accelerated acid corrosion and air oxidation tests indicate that the coating process dramatically improved oxidation and acid corrosion resistances, which are critical issues in various applications of CI magnetic particles.

  14. Development of electrically conductive DLC coated stainless steel separators for polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuo; Watanabe, Masanori; Toda, Tadao; Fujii, Toshiaki

    2013-06-01

    Polymer electrolyte fuel cell (PEFC) as one of generation devices of electrical power is rapidly expanding the market as clean energy instead of petroleum and atomic energy. Residential fuel cell goes into quantity production and introduction of fuel cell for use in automobiles starts in the year 2015 in Japan. Critical subject for making fuel cell expand is how to reduce cost of fuel cell. In this paper we describe about separator plate which domains large ratio of cost in fuel cell stack. In present time, carbon is used in material of residential fuel cell separator. Metal separators are developed in fuel cell for use in automobiles because of need of mechanical strength at first. In order to make fuel cell expand in market, further cost reduction is required. But the metal separator has problem that by using metal separator contact resistance occurred by metal corrosion increases and catalyst layer and membrane degrade. In recent time we found out to protect from corrosion and dissolution of metals by coating the film of porous free conductive DLC with plasma ion implantation and deposition technology that we have developed. Film of electrically conductive DLC was formed with high speed of 13 μm/hr by ICP plasma, and coating cost breakout was performed.

  15. Laboratory Evaluation of Light Obscuration Particle Counters used to Establish use Limits for Aviation Fuel

    DTIC Science & Technology

    2015-12-01

    5000 DISTRIBUTION A. Approved for public release: distribution unlimited. Laboratory Evaluation of Light Obscuration Particle Counters used to...To) 4. TITLE AND SUBTITLE Laboratory Evaluation of Light Obscuration Particle Counters used to Establish use Limits for Aviation Fuel 5a. CONTRACT...laboratory evaluations of automatic light obscuration particle counters to develop limits for aviation fuel cleanliness. The laboratory evaluations

  16. Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars

    PubMed Central

    Tang, Fujian; Chen, Genda; Brow, Richard K.; Koenigstein, Michael L.

    2014-01-01

    The protective performance of a sand particle-modified enamel coating on reinforcing steel bars was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS). Seven percentages of sand particles by weight were investigated: 0%, 5%, 10%, 20%, 30%, 50% and 70%. The phase composition of the enamel coating and sand particles were determined with the X-ray diffraction (XRD) technique. The surface and cross-sectional morphologies of the sand particle-modified enamel coating were characterized using scanning electron microscopy (SEM). XRD tests revealed three phases of sand particles: SiO2, CaCO3 and MgCO3. SEM images demonstrated that the enamel coating wetted well with the sand particles. However, a weak enamel coating zone was formed around the sand particles due to concentrated air bubbles, leading to micro-cracks as hydrogen gas pressure builds up and exceeds the tensile strength of the weak zone. As a result, the addition of sand particles into the enamel coating reduced both the coating and corrosion resistances. PMID:28788203

  17. Bioactive glass coatings with hydroxyapatite and Bioglass (registered) particles on Ti-based implants. 1. Processing

    SciTech Connect

    Gomez-Vega, J.M.; Saiz, E.; Tomsia, A.P.; Marshall, G.W.; Marshall, S.J.

    1999-06-01

    Silicate-based glasses with thermal expansion coefficients that match those of Ti6Al4V were prepared and used to coat Ti6Al4V by a simple enameling technique. Bioglass (BG) (registered) or hydroxyapatite (HA) particles were embedded on the coatings in order to enhance their bioactivity. HA particles were partially embedded during heating and remained firmly embedded on the coating after cooling. There was no apparent reaction at the glass/HA interface at the temperatures used in this work (800-840 degrees C). In contrast, BG particles softened and some infiltration into the glass coating took place during heat treatment. In this case, particles with sizes over 45 (mu)m were required, otherwise the particles became hollow due to the infiltration and crystallization of the glass surface. The concentration of the particles on the coating was limited to 20% of surface coverage. Concentrations above this value resulted in cracked coatings due to excessive induced stress. Cracks did not prop agate along the interfaces when coatings were subjected to Vickers indentation tests, indicating that the particle/glass and glass/metal interfaces exhibited strong bonds. Enameling, producing excellent glass/metal adhesion with well-attached bioactive particles on the surface, is a promising method of forming reliable and lasting implants which can endure substantial chemical and mechanical stresses.

  18. Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars.

    PubMed

    Tang, Fujian; Chen, Genda; Brow, Richard K; Koenigstein, Michael L

    2014-09-15

    The protective performance of a sand particle-modified enamel coating on reinforcing steel bars was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS). Seven percentages of sand particles by weight were investigated: 0%, 5%, 10%, 20%, 30%, 50% and 70%. The phase composition of the enamel coating and sand particles were determined with the X-ray diffraction (XRD) technique. The surface and cross-sectional morphologies of the sand particle-modified enamel coating were characterized using scanning electron microscopy (SEM). XRD tests revealed three phases of sand particles: SiO₂, CaCO₃ and MgCO₃. SEM images demonstrated that the enamel coating wetted well with the sand particles. However, a weak enamel coating zone was formed around the sand particles due to concentrated air bubbles, leading to micro-cracks as hydrogen gas pressure builds up and exceeds the tensile strength of the weak zone. As a result, the addition of sand particles into the enamel coating reduced both the coating and corrosion resistances.

  19. Effect of soluble polymer binder on particle distribution in a drying particulate coating.

    PubMed

    Buss, Felix; Roberts, Christine C; Crawford, Kathleen S; Peters, Katharina; Francis, Lorraine F

    2011-07-01

    Soluble polymer is frequently added to inorganic particle suspensions to provide mechanical strength and adhesiveness to particulate coatings. To engineer coating microstructure, it is essential to understand how drying conditions and dispersion composition influence particle and polymer distribution in a drying coating. Here, a 1D model revealing the transient concentration profiles of particles and soluble polymer in a drying suspension is proposed. Sedimentation, evaporation and diffusion govern particle movement with the presence of soluble polymer influencing the evaporation rate and solution viscosity. Results are summarized in drying regime maps that predict particle accumulation at the free surface or near the substrate as conditions vary. Calculations and experiments based on a model system of poly(vinyl alcohol) (PVA), silica particles and water reveal that the addition of PVA slows the sedimentation and diffusion of the particles during drying such that accumulation of particles at the free surface is more likely.

  20. Characterization of particle size distribution from diesel engines fueled with palm-biodiesel blends and paraffinic fuel blends

    NASA Astrophysics Data System (ADS)

    Lin, Yuan-Chung; Lee, Chia-Fon; Fang, Tiegang

    Biodiesels are promoted as alternative fuels and their applications in diesel engines have been investigated by many researchers. However, the particle size distribution emitted from heavy-duty diesel engines fueled with palm-biodiesel blended with premium diesel fuel and paraffinic fuel blended with palm-biodiesel has seldom been addressed. Thus, five test fuels were used in this work to study the particle size distribution: D100 (premium diesel fuel), B100 (100% palm-biodiesel), B20 (20 vol% palm-biodiesel+80 vol% D100), BP9505 (95 vol% paraffinic fuel+5 vol% palm-biodiesel) and BP8020 (80 vol% paraffinic fuel+20 vol% palm-biodiesel). A Micro-Orifice Uniform Deposit Impactor (MOUDI) equipped with aluminum filters was used to collect size-resolved samples. Experimental results indicated that palm-biodiesel blends and paraffinic fuel blends could improve combustion efficiency in diesel engines, but pure palm-biodiesel could cause incomplete combustion. Adding palm-biodiesel to diesel fuel would slightly increase particles with diameter <0.31 μm but paraffinic fuel blends could decrease particles with diameter <1 μm. The mass median diameter of overall particles (MMD o) and σg,o are 0.439 μm and 3.88 for D100; 0.380 μm and 3.24 for B20; 0.465 μm and 4.22 for B100; 1.40 μm and 4.92 for BP9505; 1.46 μm and 2.25 for BP8020. There are more particles with low aerodynamic diameters (diameter <0.31 μm) in the exhaust of D100, B20 and B100 fuels. On the other hand, a greater fraction of particulate matter of BP9505 and BP8020 existed in coarse particles (diameter: 2.5-10 μm). Energy efficiency also increases significantly by 12.3-15.1% with the introduction of paraffinic fuel blends into the engine. Nevertheless, paraffinic fuel blends also reduce the emission of particulate matters by 36.0-38.4%. Carbon monoxide was decreased by 36.8-48.5%. Total hydrocarbon is 39.6-41.7% less than diesel fuel combustion. Nitrogen oxides emission is about 5% lower for paraffinic

  1. Modeling of particles orientation in magnetic field in drying magnetic coatings

    NASA Astrophysics Data System (ADS)

    Potanin, Andrei A.; Reynolds, George; J. Hirko, Ronald

    2000-03-01

    Filament coating is studied as a model of magnetic tape manufacturing. Freshly coated filament is driven through a solenoid magnet which orients particles. After drying the coated filament, its squareness is measured as a function of the magnet position, field and the filament speed during coating. Production and model mixes are tested, which differ in dispersion quality and drying rate. A mean-field model is used to describe orientation of particles in the coating. The model fits experiments with two parameters: particles mobility and a mean-field interaction coefficient. Well dispersed kneaded mix has higher mobility and weaker interactions than non-kneaded mixes. The model well agrees with the data for squareness decay with magnet separation from the mix deposition point, thereby providing a theoretical tool for finding proper magnet position on the production coating lines.

  2. Neutronic double heterogeneity effect in particle dispersed type inert matrix fuels

    NASA Astrophysics Data System (ADS)

    Akie, H.; Takano, H.

    2006-06-01

    Rock-like oxide (ROX) fuel concept is studied in Japan for effective plutonium burning in light water reactors (LWRs). ROX is a heterogeneous fuel, where Pu containing yttria stabilized zirconia (YSZ) particles are dispersed in spinel matrix, and similar to the high temperature gas cooled reactor (HTR) fuel. The effect of such a 'double' heterogeneity (fuel, structure and coolant heterogeneity in reactor core, plus fuel heterogeneity) on HTR neutronic characteristics is important, while the effect was not taken into account in the ROX fueled LWR neutronics calculations. Here, this double heterogeneity effect is estimated for ROX fueled LWR, and compared with the Pu containing YSZ particle fueled HTR. As a result, the heterogeneity effect was negligible in the ROX-LWR system, while it is notable in YSZ-HTR system. The volume fraction of YSZ particle in the fuel region is one of the important parameter to cause the difference.

  3. A comparative study of high velocity oxygen fuel, vacuum plasma spray, and axial plasma spray for the deposition of CoNiCrAlY bond coat alloy

    NASA Astrophysics Data System (ADS)

    Scrivani, A.; Bardi, U.; Carrafiello, L.; Lavacchi, A.; Niccolai, F.; Rizzi, G.

    2003-12-01

    In the aerospace field as well as in the stationary gas turbine field, thermally sprayed coatings are used to improve the surface properties of nickel-super-alloys materials. Coatings are commonly used as bond coat and antioxidation materials (mainly MCrAlY alloys) and as thermal barrier coatings (mainly yttria partially stabilized zirconia). The purpose of the current study was to assess the properties of thermally sprayed bond coat CoNiCrAlY alloys comparing the performance of three different techniques: vacuum plasma spray (VPS), high velocity oxygen fuel (HVOF), and axial plasma spray (AxPS). The quality of the deposited films has been assessed and compared from the point of view of microstructural (porosity, oxide concentration, unmelted particles presence) and mechanical (hardness) characteristics. The surface composition and morphology of the coatings were also determined. Specific efficiency tests were performed for the three examined technologies. The highest quality coatings are obtained by VPS, but also high velocity oxygen fuel and AxPS sprayed films have interesting properties, which can make their use interesting for some applications.

  4. Diode laser cladding of Co-based composite coatings reinforced by spherical WC particles

    NASA Astrophysics Data System (ADS)

    Janicki, Damian; Górka, Jacek; Czupryński, Artur; Kwaśny, Waldemar; Żuk, Marcin

    2016-12-01

    A laser cladding system consisting of a direct diode laser with the flat-top beam profile and an off-axis powder injection nozzle has been used to fabricate Co-based (Satellite 6) metal matrix composite coatings reinforced by spherical-shaped WC particles. Non-porous coatings with the WC fraction of about 50 vol.% and a low dissolution of the WC particles in the matrix have been obtained. The heat input level affects the degree of WC dissolution and the matrix mean free path between the embedded WC particles. Comparative erosion tests between the metallic Satellite 6 and composite Satellite 6/WC coatings showed that the composite coatings exhibit a superior erosion resistance only at the oblique impingement condition. Generally, a low erosion resistance of the composite coatings at the normal impingement is mainly attributed to a very smooth interface between the spherical-shaped WC particles and the matrix alloy.

  5. Effect of coating density on oxidation resistance and Cr vaporization from solid oxide fuel cell interconnects

    NASA Astrophysics Data System (ADS)

    Talic, Belma; Falk-Windisch, Hannes; Venkatachalam, Vinothini; Hendriksen, Peter Vang; Wiik, Kjell; Lein, Hilde Lea

    2017-06-01

    Manganese cobalt spinel oxides are promising materials for protective coatings for solid oxide fuel cell (SOFC) interconnects. To achieve high density such coatings are often sintered in a two-step procedure, involving heat treatment first in reducing and then in oxidizing atmospheres. Sintering the coating inside the SOFC stack during heating would reduce production costs, but may result in a lower coating density. The importance of coating density is here assessed by characterization of the oxidation kinetics and Cr evaporation of Crofer 22 APU with MnCo1.7Fe0.3O4 spinel coatings of different density. The coating density is shown to have minor influence on the long-term oxidation behavior in air at 800 °C, evaluated over 5000 h. Sintering the spinel coating in air at 900 °C, equivalent to an in-situ heat treatment, leads to an 88% reduction of the Cr evaporation rate of Crofer 22 APU in air-3% H2O at 800 °C. The air sintered spinel coating is initially highly porous, however, densifies with time in interaction with the alloy. A two-step reduction and re-oxidation heat treatment results in a denser coating, which reduces Cr evaporation by 97%.

  6. Nafion(TM) Coats For Electrodes In Liquid-Feed Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram R.; Surampudi, Subbarao; Halpert, Gerald; Vamos, Eugene; Frank, Harvey A.

    1995-01-01

    Coating or impregnation with commercially available material enables oxidation of organic liquid fuels. Nafion(TM) investigated for use in application because of known combination of desirable characteristics: It is perfluorinated, hydrophilic, proton-conducting ion-exchange polymer exhibiting relatively high thermal and electrochemical stability and not detrimental to kinetics of electrochemical processes. Available in solubilized form and used to apply stable coats to surfaces of electrodes.

  7. Nafion(TM) Coats For Electrodes In Liquid-Feed Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram R.; Surampudi, Subbarao; Halpert, Gerald; Vamos, Eugene; Frank, Harvey A.

    1995-01-01

    Coating or impregnation with commercially available material enables oxidation of organic liquid fuels. Nafion(TM) investigated for use in application because of known combination of desirable characteristics: It is perfluorinated, hydrophilic, proton-conducting ion-exchange polymer exhibiting relatively high thermal and electrochemical stability and not detrimental to kinetics of electrochemical processes. Available in solubilized form and used to apply stable coats to surfaces of electrodes.

  8. Hydrolytic Stability of Polyurethane-Coated Fabrics Used for Collapsible Fuel Storage Containers

    DTIC Science & Technology

    2014-06-01

    reaction with water that chemically and structurally breaks down the urethane coating, resulting in cracking or extreme softening of the urethane...coated fabrics used in collapsible fuel storage containers is investigated. We immerse these fabrics in water held at an elevated temperature of 180 °F...fell apart after only 42 days of water immersion, while the two Cooley fabrics fell apart after 70 days. The three materials available from Seaman

  9. A methodology to study impactor particle reentrainment and a proposed stage coating for the NGI.

    PubMed

    Rissler, Jenny; Asking, Lars; Dreyer, Jakob Kisbye

    2009-12-01

    Mass-weighted aerodynamic particle-size distribution (APSD) is a key attribute for pharmaceutical products developed to deliver drugs to or through the lungs. In development and quality control, APSD is primarily determined using multistage cascade impactors. For impactor techniques, particle reentrainment is critical because it may lead to an overestimation of the respirable fraction. To avoid reentrainment, the collection surfaces need to be coated with a suitable material. In this study a method was developed to test flow dependence of particle reentrainment in the Next Generation Pharmaceutical Impactor (NGI) at flow rates ranging from 20 to 80 L/min, and was used to test three coating materials: glycerol coating, aqueous coating with, and without soaked filter paper. Uncoated cups were also tested. In the experimental setup a Vilnius Aerosol Generator generated a flow-independent dry powder aerosol, consisting of micronized insulin. The glycerol coating was not well suited to reduce particle reentrainment at flows >or=40 L/min. The soaked filter paper coating was found to give nearly the same particle size distributions regardless of flow and was therefore judged to be the best of those tested. Using liquid only, without the filter paper, gave the same particle size distributions as soaked filter paper for flows or=60 L/min particle reentrainment increased with flow. However, for most applications liquid coating reduced particle reentrainment to an extent at which further reduction was irrelevant. Particle reentrainment was prevalent for uncoated cups at all flow rates tested. This study shows the advantage of using a stable and flow-independent aerosol generation method to examine particle reentrainment at various flows through the NGI. For insulin dry powder, the use of an aqueous solution as cup coating, preferably with a filter, reduced particle reentrainment to a minimum. The results were confirmed in a study with a DPI.

  10. Effect of Particle Morphology and Size Distribution on Cold-Sprayed Pure Titanium Coatings

    NASA Astrophysics Data System (ADS)

    Wong, W.; Vo, P.; Irissou, E.; Ryabinin, A. N.; Legoux, J.-G.; Yue, S.

    2013-10-01

    The effects of commercially pure titanium particle morphology (spherical, sponge, and irregular) and size distributions (mean particle sizes of 20-49 μm) on the cold spray process and resulting coating properties were investigated. Numerous powder and coating characterizations were performed including: powder oxygen and nitrogen contents, powder flowability, powder compressibility, coating microhardness, coating porosity, LOM/SEM analyses, and XRD. Compared to spherical powders, the sponge and irregular CP-Ti powders had higher oxygen content, poorer powder flowability, higher compression ratio, lower powder packing factor, and higher average particle impact velocities. XRD results showed no new phases present when comparing the various feedstock powders to corresponding coatings. A higher particle temperature was also obtained with larger particle size for all feedstock powder morphologies processed with the same set of spray parameters. A spherical powder with 29 μm mean particle size was found to have the lowest porosity coating and best cold sprayability. The relationships of several as-cold sprayed coating characteristics to the ratio of particle impact and critical velocities were also discussed.

  11. Fission-product behaviour in irradiated TRISO-coated particles: Results of the HFR-EU1bis experiment and their interpretation

    NASA Astrophysics Data System (ADS)

    Barrachin, M.; Dubourg, R.; de Groot, S.; Kissane, M. P.; Bakker, K.

    2011-08-01

    It is important to understand fission-product (FP) and kernel micro-structure evolution in TRISO-coated fuel particles. FP behaviour, while central to severe-accident evaluation, impacts: evolution of the kernel oxygen potential governing in turn carbon oxidation (amoeba effect and pressurization); particle pressurization through fission-gas release from the kernel; and coating mechanical resistance via reaction with some FPs (Pd, Cs, Sr). The HFR-Eu1bis experiment irradiated five HTR fuel pebbles containing TRISO-coated UO 2 particles and went beyond current HTR specifications (e.g., central temperature of 1523 K). This study presents ceramographic and EPMA examinations of irradiated urania kernels and coatings. Significant evolutions of the kernel (grain structure, porosity, metallic-inclusion size, intergranular bubbles) as a function of temperature are shown. Results concerning FP migration are presented, e.g., significant xenon, caesium and palladium release from the kernel, molybdenum and ruthenium mainly present in metallic precipitates. The observed FP and micro-structural evolutions are interpreted and explanations proposed. The effect of high flux rate and high temperature on fission-gas behaviour, grain-size evolution and kernel swelling is discussed. Furthermore, Cs, Mo and Zr behaviour is interpreted in connection with oxygen-potential. This paper shows that combining state-of-the-art post-irradiation examination and state-of-the-art modelling fundamentally improves understanding of HTR fuel behaviour.

  12. SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

    NASA Astrophysics Data System (ADS)

    Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; Allen, Todd R.

    2016-11-01

    Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy's Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representative of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.

  13. SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

    DOE PAGES

    Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; ...

    2016-08-15

    Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy’s Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representativemore » of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Finally, insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.« less

  14. SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

    SciTech Connect

    Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; Allen, Todd R.

    2016-08-15

    Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy’s Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representative of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Finally, insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.

  15. SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

    SciTech Connect

    Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; Allen, Todd R.

    2016-08-15

    Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy’s Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representative of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Finally, insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.

  16. Fabrication and Characterization of Surrogate Fuel Particles Using the Spark Erosion Method

    NASA Astrophysics Data System (ADS)

    Metzger, Kathryn E.

    In light of the disaster at the Fukushima Daiichi Nuclear Plant, the Department of Energy's Advanced Fuels Program has shifted its interest from enhanced performance fuels to enhanced accident tolerance fuels. Dispersion fuels possess higher thermal conductivities than traditional light water reactor fuel and as a result, offer improved safety margins. The benefits of a dispersion fuel are due to the presence of the secondary non-fissile phase (matrix), which serves as a barrier to fission products and improves the overall thermal performance of the fuel. However, the presence of a matrix material reduces the fuel volume, which lowers the fissile content of dispersion. This issue can be remedied through the development of higher density fuel phases or through an optimization of fuel particle size and volume loading. The latter requirement necessitates the development of fabrication methods to produce small, micron-order fuel particles. This research examines the capabilities of the spark erosion process to fabricate particles on the order of 10 μm. A custom-built spark erosion device by CT Electromechanica was used to produce stainless steel surrogate fuel particles in a deionized water dielectric. Three arc intensities were evaluated to determine the effect on particle size. Particles were filtered from the dielectric using a polycarbonate membrane filter and vacuum filtration system. Fabricated particles were characterized via field emission scanning electron microscopy (FESEM), laser light particle size analysis, energy-dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), and gas pycnometry. FESEM images reveal that the spark erosion process produces highly spherical particles on the order of 10 microns. These findings are substantiated by the results of particle size analysis. Additionally, EDS and XRD results indicate the presence of oxide phases, which suggests the dielectric reacted with the molten debris during particle formation.

  17. Identification of Silver and Palladium in Irradiated TRISO Coated Particles of the AGR-1 Experiment

    SciTech Connect

    van Rooyen, Y. J.; Lillo, T. M.; Wu, Y. Q.

    2014-03-01

    Evidence of the release of certain metallic fission product through intact tristructural isotropic (TRISO) particles has been seen for decades around the world, as well as in the recent AGR-1 experiment at Idaho National Laboratory (INL). However, understanding the basic mechanism of transport is still lacking. This understanding is important because the TRISO coating is part of the high temperature gas reactor functional containment and critical for the safety strategy for licensing purposes. Our approach to identify fission products in irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Filtered TEM (EFTEM), has led to first-of-a-kind data at the nano-scale indicating the presence of silver at triple points and grain boundaries of the SiC layer in the TRISO particle. Cadmium was also found in the triple junctions. In this initial study, the silver was only identified in SiC grain boundaries and triple points on the edge of the SiC-IPyC interface up to a depth of approximately 0.5 um. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries. Additionally spherical nano-sized palladium rich precipitates were found inside the SiC grains. These nano-sized Pd precipitates were distributed up to a depth of 5 um away from the SiC-IPyC interlayer. No silver was found in the center of the micron-sized fission product precipitates using these techniques, although silver was found on the outer edge of one of the Pd-U-Si containing precipitates which was facing the IPyC layer. Only Pd-U containing precipitates were identified in the IPyC layer and no silver was identified in the IPyC layer. The identification of silver alongside the grain boundaries and the findings of Pd alongside grain boundaries as well as inside the grains, provide significant knowledge for understanding silver and palladium transport in TIRSO fuel, which has been

  18. An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

    SciTech Connect

    Allain, Jean-Paul

    2014-09-05

    A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

  19. LaCrO3/CuFe2O4 Composite-Coated Crofer 22 APU Stainless Steel Interconnect of Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Hosseini, Seyedeh Narjes; Enayati, Mohammad Hossein; Karimzadeh, Fathallah; Dayaghi, Amir Masoud

    2017-07-01

    Rapidly rising contact resistance and cathode Cr poisoning are the major problems associated with unavoidable chromia scale growth on ferritic stainless steel (FSS) interconnects of solid oxide fuel cells. This work investigates the performance of the novel screen-printed composite coatings consisting of dispersed conductive LaCrO3 particles in a CuFe2O4 spinel matrix for Crofer 22 APU FSS, with emphasis on the oxidation behavior and electrical conductivity of these coatings. The results show that the presence of protective spinel coating, accompanied by the effective role of LaCrO3 particle incorporation, prevents the Cr2O3 subscale growth as well as chromium migration into the coating surface at the end of 400 hours of oxidation at 1073 K (800 °C) in air. In addition, the composite coatings decreased the area specific resistance (ASR) from 51.7 and 13.8 mΩ cm2 for uncoated and spinel-coated samples, respectively, to a maximum of 7.7 mΩ cm2 for composite-coated samples after 400 hours of oxidation.

  20. Ice formation on nitric acid coated dust particles: Laboratory and modeling studies

    SciTech Connect

    Kulkarni, Gourihar R.; Zhang, Kai; Zhao, Chun; Nandasiri, Manjula I.; Shutthanandan, V.; Liu, Xiaohong; Fast, Jerome D.; Berg, Larry K.

    2015-08-16

    Changes in the ice nucleation characteristics of atmospherically relevant mineral dust particles due to nitric acid coating are not well understood. Further, the atmospheric implications of dust coating on ice-cloud properties under different assumptions of primary ice nucleation mechanisms are unknown. We investigated ice nucleation ability of Arizona test dust, illite, K-feldspar and quartz as a function of temperature (-25 to -30°C) and relative humidity with respect to water (75 to 110%). Particles were size selected at 250 nm and transported (bare or coated) to the ice nucleation chamber to determine the fraction of particles nucleating ice at various temperature and water saturation conditions. All dust nucleated ice at water-subsaturated conditions, but the coated particles showed a reduction in their ice nucleation ability compared to bare particles. However, at water-supersaturated conditions, we observed that bare and coated particles had nearly similar ice nucleation characteristics. X-ray diffraction patterns indicated that structural properties of bare dust particles modified after acid treatment. We found that lattice parameters were slightly different, but crystallite sizes of the coated particles were reduced compared to bare particles. Next, single-column model results show that simulated ice crystal number concentrations mostly depends upon fraction of particles that are coated, primary ice nucleation mechanisms, and the competition between ice nucleation mechanisms to nucleate ice. In general, we observed that coating modify the ice-cloud properties and the picture of ice and mixed-phase cloud evolution is complex when different primary ice nucleation mechanisms are competing for fixed water vapor mass.

  1. CoxFe1-x oxide coatings on metallic interconnects for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Shen, Fengyu; Lu, Kathy

    2016-10-01

    In order to improve the performance of Cr-containing steel as an interconnect material for solid oxide fuel cells, CoFe alloy coatings with Co:Fe ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 are deposited by electrodeposition and then oxidized to CoxFe1-x oxide coatings with a thickness of ∼6 μm as protective layers on the interconnect. The area specific resistance of the coated interconnect increases with the Fe content. Higher Co content oxide coatings are more effective in limiting the growth of the chromia scale while all coatings are effective in inhibiting Cr diffusion and evaporation. With the Co0.8Fe0.2 oxide coated interconnect, the electrochemical performance of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode is improved. Only 1.54 atomic percentage of Cr is detected on the surface of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode while no Cr is detected 0.66 μm or more into the cathode. CoxFe1-x oxide coatings are promising candidates for solid oxide fuel cell interconnects with the advantage of using existing cathode species for compatibility and performance enhancement.

  2. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles.

    PubMed

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-02-02

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air.

  3. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles

    PubMed Central

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-01-01

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air. PMID:26831205

  4. Laser cladding of Inconel 625-based composite coatings reinforced by porous chromium carbide particles

    NASA Astrophysics Data System (ADS)

    Janicki, Damian

    2017-09-01

    Inconel 625/Cr3C2 composite coatings were produced via a laser cladding process using Cr3C2 reinforcing particles presenting an open porosity of about 60%. A laser cladding system used consisted of a direct diode laser with a rectangular beam spot and the top-hat beam profile, and an off-axis powder injection nozzle. The microstructural characteristics of the coatings was investigated with the use of scanning electron microscopy and X-ray diffraction. A complete infiltration of the porous structure of Cr3C2 reinforcing particles and low degree of their dissolution have been achieved in a very narrow range of processing parameters. Crack-free composite coatings having a uniform distribution of the Cr3C2 particles and their fraction up to 36 vol% were produced. Comparative erosion tests between the Inconel 625/Cr3C2 composite coatings and the metallic Inconel 625 coatings were performed following the ASTM G 76 standard test method. It was found that the composite coatings have a significantly higher erosion resistance to that of metallic coatings for both 30° and 90° impingement angles. Additionally, the erosion performances of composite coatings were similar for both the normal and oblique impact conditions. The erosive wear behaviour of composite coatings is discussed and related to the unique microstructure of these coatings.

  5. Copper Iron Conversion Coating for Solid Oxide Fuel Cell Interconnects

    NASA Astrophysics Data System (ADS)

    Grolig, Jan Gustav; Alnegren, Patrik; Froitzheim, Jan; Svensson, Jan-Erik

    2015-11-01

    A conversion coating of iron and copper was investigated with the purpose of increasing the performance of Sanergy HT as a potential SOFC interconnect material. Samples were exposed to a simulated cathode atmosphere (air, 3 % H2O) for durations of up to 1000 h at 850 °C. Their performance in terms of corrosion, chromium evaporation and electrical resistance (ASR) was monitored and compared to uncoated and cobalt-coated Sanergy HT samples. The copper iron coating had no negative effects on corrosion protection and decreased chromium evaporation by about 80%. An Area Specific Resistance (ASR) of 10 mΩcm2 was reached after 1000 h of exposure. Scanning Electron Microscopy revealed well adherent oxide layers comprised of an inner chromia layer and an outer spinel oxide layer.

  6. Kaolinite particles as ice nuclei: learning from the use of different kaolinite samples and different coatings

    NASA Astrophysics Data System (ADS)

    Wex, H.; DeMott, P. J.; Tobo, Y.; Hartmann, S.; Rösch, M.; Clauss, T.; Tomsche, L.; Niedermeier, D.; Stratmann, F.

    2014-06-01

    Kaolinite particles from two different sources (Fluka and Clay Minerals Society (CMS)) were examined with respect to their ability to act as ice nuclei (IN). This was done in the water-subsaturated regime where often deposition ice nucleation is assumed to occur, and for water-supersaturated conditions, i.e., in the immersion freezing mode. Measurements were done using a flow tube (the Leipzig Aerosol Cloud Interaction Simulator, LACIS) and a continuous-flow diffusion chamber (CFDC). Pure and coated particles were used, with coating thicknesses of a few nanometers or less, where the coating consisted of levoglucosan, succinic acid or sulfuric acid. In general, it was found that the coatings strongly reduced deposition ice nucleation. Remaining ice formation in the water-subsaturated regime could be attributed to immersion freezing, with particles immersed in concentrated solutions formed by the coatings. In the immersion freezing mode, ice nucleation rate coefficients jhet from both instruments agreed well with each other, particularly when the residence times in the instruments were accounted for. Fluka kaolinite particles coated with either levoglucosan or succinic acid showed the same IN activity as pure Fluka kaolinite particles; i.e., it can be assumed that these two types of coating did not alter the ice-active surface chemically, and that the coatings were diluted enough in the droplets that were formed prior to the ice nucleation, so that freezing point depression was negligible. However, Fluka kaolinite particles, which were either coated with pure sulfuric acid or were first coated with the acid and then exposed to additional water vapor, both showed a reduced ability to nucleate ice compared to the pure particles. For the CMS kaolinite particles, the ability to nucleate ice in the immersion freezing mode was similar for all examined particles, i.e., for the pure ones and the ones with the different types of coating. Moreover, jhet derived for the CMS

  7. Ice Nucleation and Droplet Formation by Bare and Coated Soot Particles

    SciTech Connect

    Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

    2011-09-13

    We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles representative of those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

  8. Ice Nucleation and Droplet Formation by Bare and Coated Black Carbon Particles

    SciTech Connect

    Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

    2011-10-13

    We have studied the ice formation at heterogeneous and homogeneous temperatures, as well as droplet activation and hygroscopicity of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span a relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation with a comparison to a well characterized mineral dust particle that acts as an efficient ice nucleus, as well as particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude from our studies that both uncoated and coated soot particles are unlikely to contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

  9. Particle Size, Surface Coating, and PEGylation Influence the Biodistribution of Quantum Dots in Living Mice

    PubMed Central

    Schipper, Meike L.; Iyer, Gopal; Koh, Ai Leen; Cheng, Zhen; Ebenstein, Yuval; Aharoni, Assaf; Keren, Shay; Bentolila, Laurent A.; Li, Jianquing; Rao, Jianghong; Chen, Xiaoyuan; Banin, Uri; Wu, Anna M.; Sinclair, Robert; Weiss, Shimon

    2011-01-01

    This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near-infrared-emitting quantum dots (QDs) in mice. Polymer- or peptide-coated 64Cu-labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region-of-interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6–9 and 2–3, respectively. Small particles are in part renally excreted. Peptide-coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects. PMID:19051182

  10. Zirconia-coated carbonyl-iron-particle-based magnetorheological fluid for polishing optical glasses and ceramics

    SciTech Connect

    Shafrir, Shai N.; Romanofsky, Henry J.; Skarlinski, Michael; Wang, Mimi; Miao, Chunlin; Salzman, Sivan; Chartier, Taylor; Mici, Joni; Lambropoulos, John C.; Shen Rui; Yang Hong; Jacobs, Stephen D.

    2009-12-10

    We report on magnetorheological finishing (MRF) spotting experiments performed on glasses and ceramics using a zirconia-coated carbonyl-iron (CI)-particle-based magnetorheological (MR) fluid. The zirconia-coated magnetic CI particles were prepared via sol-gel synthesis in kilogram quantities. The coating layer was {approx}50-100 nm thick, faceted in surface structure, and well adhered. Coated particles showed long-term stability against aqueous corrosion. ''Free'' nanocrystalline zirconia polishing abrasives were cogenerated in the coating process, resulting in an abrasive-charged powder for MRF. A viable MR fluid was prepared simply by adding water. Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion. Stable material removal rates and smooth surfaces inside spots were obtained.

  11. High Power Diode Laser-Treated HP-HVOF and Twin Wire Arc-Sprayed Coatings for Fossil Fuel Power Plants

    NASA Astrophysics Data System (ADS)

    Mann, B. S.

    2013-08-01

    This article deals with high power diode laser (HPDL) surface modification of twin wire arc-sprayed (TWAS) and high pressure high velocity oxy-fuel (HP-HVOF) coatings to combat solid particle erosion occurring in fossil fuel power plants. To overcome solid particle impact wear above 673 K, Cr3C2-NiCr-, Cr3C2-CoNiCrAlY-, and WC-CrC-Ni-based HVOF coatings are used. WC-CoCr-based HVOF coatings are generally used below 673 K. Twin wire arc (TWA) spraying of Tafa 140 MXC and SHS 7170 cored wires is used for a wide range of applications for a temperature up to 1073 K. Laser surface modification of high chromium stainless steels for steam valve components and LPST blades is carried out regularly. TWA spraying using SHS 7170 cored wire, HP-HVOF coating using WC-CoCr powder, Ti6Al4V alloy, and high chromium stainless steels (X20Cr13, AISI 410, X10CrNiMoV1222, 13Cr4Ni, 17Cr4Ni) were selected in the present study. Using robotically controlled parameters, HPDL surface treatments of TWAS-coated high strength X10CrNiMoV1222 stainless steel and HP-HVOF-coated AISI 410 stainless steel samples were carried out and these were compared with HPDL-treated high chromium stainless steels and titanium alloy for high energy particle impact wear (HEPIW) resistance. The HPDL surface treatment of the coatings has improved the HEPIW resistance manifold. The improvement in HPDL-treated stainless steels and titanium alloys is marginal and it is not comparable with that of HPDL-treated coatings. These coatings were also compared with "as-sprayed" coatings for fracture toughness, microhardness, microstructure, and phase analyses. The HEPIW resistance has a strong relationship with the product of fracture toughness and microhardness of the HPDL-treated HP-HVOF and TWAS SHS 7170 coatings. This development opens up a possibility of using HPDL surface treatments in specialized areas where the problem of HEPIW is very severe. The HEPIW resistance of HPDL-treated high chromium stainless steels and

  12. Characterization of diesel particles: effects of fuel reformulation, exhaust aftertreatment, and engine operation on particle carbon composition and volatility.

    PubMed

    Alander, Timo J A; Leskinen, Ari P; Raunemaa, Taisto M; Rantanen, Leena

    2004-05-01

    Diesel exhaust particles are the major constituent of urban carbonaceous aerosol being linked to a large range of adverse environmental and health effects. In this work, the effects of fuel reformulation, oxidation catalyst, engine type, and engine operation parameters on diesel particle emission characteristics were investigated. Particle emissions from an indirect injection (IDI) and a direct injection (DI) engine car operating under steady-state conditions with a reformulated low-sulfur, low-aromatic fuel and a standard-grade fuel were analyzed. Organic (OC) and elemental (EC) carbon fractions of the particles were quantified by a thermal-optical transmission analysis method and particle size distributions measured with a scanning mobility particle sizer (SMPS). The particle volatility characteristics were studied with a configuration that consisted of a thermal desorption unit and an SMPS. In addition, the volatility of size-selected particles was determined with a tandem differential mobility analyzer technique. The reformulated fuel was found to produce 10-40% less particulate carbon mass compared to the standard fuel. On the basis of the carbon analysis, the organic carbon contributed 27-61% to the carbon mass of the IDI engine particle emissions, depending on the fuel and engine operation parameters. The fuel reformulation reduced the particulate organic carbon emissions by 10-55%. In the particles of the DI engine, the organic carbon contributed 14-26% to the total carbon emissions, the advanced engine technology, and the oxidation catalyst, thus reducing the OC/EC ratio of particles considerably. A relatively good consistency between the particulate organic fraction quantified with the thermal optical method and the volatile fraction measured with the thermal desorption unit and SMPS was found.

  13. Examination of the surface coating removed from K-East Basin fuel elements

    SciTech Connect

    Abrefah, J.; Marschman, S.C.; Jenson, E.D.

    1998-05-01

    This report provides the results of studies conducted on coatings discovered on the surfaces of some N-Reactor spent nuclear fuel (SNF) elements stored at the Hanford K-East Basin. These elements had been removed from the canisters and visually examined in-basin during FY 1996 as part of a series of characterization tests. The characterization tests are being performed to support the Integrated Process Strategy developed to package, dry, transport, and store the SNF in an interim storage facility on the Hanford site. Samples of coating materials were removed from K-East canister elements 2350E and 2540E, which had been sent, along with nine other elements, to the Postirradiation Testing Laboratory (327 Building) for further characterization following the in-basin examinations. These coating samples were evaluated by Pacific Northwest National Laboratory using various analytical methods. This report is part of the overall studies to determine the drying behavior of corrosion products associated with the K-Basin fuel elements. Altogether, five samples of coating materials were analyzed. These analyses suggest that hydration of the coating materials could be an additional source of moisture in the Multi-Canister Overpacks being used to contain the fuel for storage.

  14. Application of Gelatin-Coated Magnetic Particles for Isolation of Genomic DNA from Bones.

    PubMed

    Khanpetch, Pongsak; Intorasoot, Sorasak; Prasitwattanseree, Sukon; Mekjaidee, Karnda; Mahakkanukrauh, Pasuk

    2015-07-01

    To develop a method for human genomic DNA extraction from bone using gelatin-coated magnetic particles. Thirty human metacarpal with the bone age ranging from 36 to 93 years were included in the present study. Genomic DNA was extracted from bones using gelatin-coated magnetic particles. The concentration and purity of DNA were analyzed in comparison with a reference method. In addition, the quality of extracted DNA was examined for sex determination by conventional polymerase chain reaction (PCR). The average DNA concentration using gelatin coated magnetic particles exhibited approximately 15 times higher than a reference method with an insignificantly difference of the DNA purity in both methods. Twelve (40%) and fifteen (50%) samples out of thirty DNA isolated using established and reference method, respectively, could be amplified and sex correctly determined by PCR. Gelatin coated magnetic particle is rapid, simple, and well-suited for isolation of DNA from bones.

  15. Lanthanum oxide-coated stainless steel for bipolar plates in solid oxide fuel cells (SOFCs)

    NASA Astrophysics Data System (ADS)

    Yoon, Jong Seol; Lee, Jun; Hwang, Hae Jin; Whang, Chin Myung; Moon, Ji-Woong; Kim, Do-Hyeong

    Solid oxide fuel cells typically operate at temperatures of about 1000 °C. At these temperatures only ceramic interconnects such as LaCrO 3 can be employed. The development of intermediate-temperature solid oxide fuel cells (IT-SOFCs) can potentially bring about reduced manufacturing costs as it makes possible the use of an inexpensive ferritic stainless steel (STS) interconnector. However, the STS suffers from Cr 2O 3 scale formation and a peeling-off phenomenon at the IT-SOFC operating temperature in an oxidizing atmosphere. Application of an oxidation protective coating is an effective means of providing oxidation resistance. In this study, we coated an oxidation protective layer on ferritic stainless steel using a precursor solution prepared from lanthanum nitrate, ethylene glycol, and nitric acid. Heating the precursor solution at 80 °C yielded a spinable solution for coating. A gel film was coated on a STS substrate by a dip coating technique. At the early stage of the heat-treatment, lanthanum-containing oxides such as La 2O 3 and La 2CrO 6 formed, and as the heat-treatment temperature was increased, an oxidation protective perovskite-type LaCrO 3 layer was produced by the reaction between the lanthanum-containing oxide and the Cr 2O 3 scale on the SUS substrate. As the concentration of La-containing precursor solution was increased, the amount of La 2O 3 and La 2CrO 6 phases was gradually increased. The coating layer, which was prepared from a precursor solution of 0.8 M, was composed of LaCrO 3 and small amounts of (Mn,Cr)O 4 spinel. A relatively dense coating layer without pin-holes was obtained by heating the gel coating layer at 1073 K for 2 h. Microstructures and oxidation behavior of the La 2O 3-coated STS444 were investigated.

  16. One-step electrodeposition of self-assembled colloidal particles: a novel strategy for biomedical coating.

    PubMed

    Sun, Jiadi; Liu, Xiaoya; Meng, Long; Wei, Wei; Zheng, Yufeng

    2014-09-23

    A novel biomedical coating was prepared from self-assembled colloidal particles through direct electrodeposition. The particles, which are photo-cross-linkable and nanoscaled with a high specific surface area, were obtained via self-assembly of amphiphilic poly(γ-glutamic acid)-g-7-amino-4-methylcoumarin (γ-PGA-g-AMC). The size, morphology, and surface charge of the resulting colloidal particles and their dependence on pH, initial concentrations, and UV irradiation were successfully studied. A nanostructured coating was formed in situ on the surface of magnesium alloys by electrodeposition of colloidal particles. The composition, morphology, and phase of the coating were monitored using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and X-ray diffraction. The corrosion test showed that the formation of the nanostructured coating on magnesium alloys effectively improved their initial anticorrosion properties. More importantly, the corrosion resistance was further enhanced by chemical photo-cross-linking. In addition, the low cytotoxicity of the coated samples was confirmed by MTT assay against NIH-3T3 normal cells. The contribution of our work lies in the creation of a novel strategy to fabricate a biomedical coating in view of the versatility of self-assembled colloidal particles and the controllability of the electrodeposition process. It is believed that our work provides new ideas and reliable data to design novel functional biomedical coatings.

  17. Microencapsulation and characterization of poly(vinyl alcohol)-coated titanium dioxide particles for electrophoretic display

    NASA Astrophysics Data System (ADS)

    Lee, Jeongwoo; Hong, Jinho; Park, Dong Wha; Shim, Sang Eun

    2010-02-01

    Titanium dioxide (TiO 2) particles were coated by poly(vinyl alcohol) (PVA) via a simple method of coacervation without a conventionally practiced polymerization step. Transmission electron microscopy (TEM) images clearly showed that the successful coating was achieved on the surface of TiO 2 particles. The average thickness of PVA coating layer was about 1.07 μm and the amount of coated PVA was 1.40 wt.% relative to TiO 2. The existence of PVA layer on TiO 2 was also verified from FT-IR spectra. The PVA-coated TiO 2 particles were further microencapsulated via coacervation of gelatin and gum Arabic. Regarding the performance of the resulting microcapsules, the resulting PVA-coated TiO 2 particles showed both a good electrophoretic movement and a good bistability in the microcapsules. Therefore, these microcapsules embedding PVA-coated TiO 2 particles can be used as a good candidate for the electrophoretic displays.

  18. Creep resistant, metal-coated LiFeO.sub.2 anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, Ashok C.

    1994-01-01

    A porous, creep-resistant, metal-coated, LiFeO.sub.2 ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well.

  19. Creep resistant, metal-coated LiFeO[sub 2] anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, A.C.

    1994-08-23

    A porous, creep-resistant, metal-coated, LiFeO[sub 2] ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well. 11 figs.

  20. Moisture desorption in mechanically masticated fuels: effects of particle fracturing and fuelbed compaction

    Treesearch

    Jesse K. Kreye; J.Morgan Varner; Eric E. Knapp

    2012-01-01

    Mechanical mastication is increasingly used as a wildland fuel treatment, reducing standing trees and shrubs to compacted fuelbeds of fractured woody fuels. One major shortcoming in our understanding of these fuelbeds is how particle fracturing influences moisture gain or loss, a primary determinant of fire behaviour. To better understand fuel moisture dynamics, we...

  1. A study of the magnetic properties of cobalt ferrite-coated zinc ferrite particles

    NASA Astrophysics Data System (ADS)

    Tang, Huan; Du, You-wei; Qiu, Zi-qiang; Walker, J. C.

    1987-04-01

    Nearly spherical Zn0.2Fe2.8O4 particles coated with an epitaxial layer of CoFe2O4 ferrites of various thicknesses were studied with Mössbauer spectroscopy. Measurements reveal that the magnetic structures of these particles are different at room temperature and liquid nitrogen or liquid helium temperatures, indicating the existence of a Verwey transition, which occurs between 77 and 119 K. Coating of Co-ferrite has no sizable effect on the transition.

  2. Chromium vaporization from mechanically deformed pre-coated interconnects in Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Falk-Windisch, Hannes; Sattari, Mohammad; Svensson, Jan-Erik; Froitzheim, Jan

    2015-11-01

    Cathode poisoning, associated with Cr evaporation from interconnect material, is one of the most important degradation mechanisms in Solid Oxide Fuel Cells when Cr2O3-forming steels are used as the interconnect material. Coating these steels with a thin Co layer has proven to decrease Cr vaporization. To reduce production costs, it is suggested that thin metallic PVD coatings be applied to each steel strip before pressing the material into interconnect shape. This process would enable high volume production without the need for an extra post-coating step. However, when the pre-coated material is mechanically deformed, cracks may form and lower the quality of the coating. In the present study, Chromium volatilization is measured in an air-3% H2O environment at 850 °C for 336 h. Three materials coated with 600 nm Co are investigated and compared to an uncoated material. The effect of deformation is investigated on real interconnects. Microscopy observations reveal the presence of cracks in the order of several μm on the deformed pre-coated steel. However, upon exposure, the cracks can heal and form a continuous surface oxide rich in Co and Mn. As an effect of the rapid healing, no increase in Cr vaporization is measured for the pre-coated material.

  3. Duplex coating of electroless nickel and HVOF (high-velocity oxygen fuel) sprayed WC-Co

    NASA Astrophysics Data System (ADS)

    Jokinen, P.; Korpiola, K.; Mahiout, A.

    2000-06-01

    The porosity of thermal sprayed coatings is usually a problem when coatings are used in wet corrosion application. The porosity allows media to penetrate to the surface of the base material. Corrosion spreads rapidly and the coating loses contact with the substrate and delaminates. This problem can be initiated by impregnating different polymers into the pores. An alternative approach has been tested in the present work to prevent corrosion of cemented carbide coated carbon steel in wet corrosion environments. Carbon steel substrates were coated with a thin film of electroless nickel (electroless nickel plating) and then HVOF (High-Velocity Oxygen Fuel) sprayed with cemented carbide. Reference specimens without electroless nickel were sprayed at the same time. The microhardness of the specimens was measured and the coating structure examined using optical microscopy and X-ray diffractometry (XRD). The bond between the layers and the base material was examined by means of a bend test. A salt chamber test was also performed for the specimens. The structure of the electroless nickel layer was crystalline as a result of the HVOF spraying. There were no cracks in the nickel layer, if the layer was about 20 µm thick. According to the results of the bend test, the adhesion between coatings and substrate was good, and there was no difference between the duplex-coated specimen and the reference specimen. A sample with a thin nickel layer under an HVOF sprayed cemented carbide did not exhibit corrosion after 8 h in the salt chamber test.

  4. THE INFLUENCE OF CARBON BURNOUT ON SUBMICRON PARTICLE FORMATION FROM EMULSIFIED FUEL OIL COMBUSTION

    EPA Science Inventory

    The paper gives results of an examination of particle behavior and particle size distributions from the combustion of different fuel oils and emulsified fuels in three experimental combusators. Results indicate that improved carbon (C) burnout from fule oil combustion, either by...

  5. THE INFLUENCE OF CARBON BURNOUT ON SUBMICRON PARTICLE FORMATION FROM EMULSIFIED FUEL OIL COMBUSTION

    EPA Science Inventory

    The paper gives results of an examination of particle behavior and particle size distributions from the combustion of different fuel oils and emulsified fuels in three experimental combusators. Results indicate that improved carbon (C) burnout from fule oil combustion, either by...

  6. Minimum Fuel Trajectory Design in Multiple Dynamical Environments Utilizing Direct Transcription Methods and Particle Swarm Optimization

    DTIC Science & Technology

    2016-03-01

    MINIMUM-FUEL TRAJECTORY DESIGN IN MULTIPLE DYNAMICAL ENVIRONMENTS UTILIZING DIRECT TRANSCRIPTION METHODS AND PARTICLE SWARM OPTIMIZATION THESIS...250 MINIMUM-FUEL TRAJECTORY DESIGN IN MULTIPLE DYNAMICAL ENVIRONMENTS UTILIZING DIRECT TRANSCRIPTION METHODS AND PARTICLE SWARM OPTIMIZATION THESIS... Education and Training Command in Partial Fulfillment of the Requirements for the Degree of Master of Science in Astronautical Engineering Alfredo G

  7. Laser induction hybrid rapid cladding of WC particles reinforced NiCrBSi composite coatings

    NASA Astrophysics Data System (ADS)

    Zhou, Shengfeng; Dai, Xiaoqin

    2010-05-01

    In order to investigate the microstructure characteristics and properties of Ni-based WC composite coatings containing a relatively large amount of WC particles by laser induction hybrid rapid cladding (LIHRC) and compare to the individual laser cladding without preheating, Ni60A + 35 wt.% WC composite coatings are deposited on A3 steel plates by LIHRC and the individual laser cladding without preheating. The composite coating produced by the individual laser cladding without preheating exhibits many cracks and pores, while the smooth composite coating without cracks and pores is obtained by LIHRC. Moreover, the cast WC particles take on the similar dissolution characteristics in Ni60A + 35 wt.% WC composite coatings by LIHRC and the individual laser cladding without preheating. Namely, the completely dissolved WC particles interact with Ni-based alloy solvent to precipitate the blocky and herringbone carbides, while the partially dissolved WC particles still preserve the primary lamellar eutectic structure. A few WC particles are split at the interface of WC and W 2C, and then interact with Ni-based alloy solvent to precipitate the lamellar carbides. Compared with the individual laser cladding without preheating, LIHRC has the relatively lower temperature gradient and the relatively higher laser scanning speed. Therefore, LIHRC can produce the crack-free composite coating with relatively higher microhardness and relatively more homogeneous distribution of WC particles and is successfully applied to strengthen the corrugated roller, showing that LIHRC process has a higher efficiency and good cladding quality.

  8. Investigations on the humidity-induced transformations of salbutamol sulphate particles coated with L-leucine.

    PubMed

    Raula, Janne; Thielmann, Frank; Kansikas, Jarno; Hietala, Sami; Annala, Minna; Seppälä, Jukka; Lähde, Anna; Kauppinen, Esko I

    2008-10-01

    The crystallization and structural integrity of micron-sized inhalable salbutamol sulphate particles coated with L-leucine by different methods are investigated at different humidities. The influence of the L-leucine coating on the crystallization of salbutamol sulphate beneath the coating layer is explored. The coated particles are prepared by an aerosol flow reactor method, the formation of the L-leucine coating being controlled by the saturation conditions of the L-leucine. The coating is formed by solute diffusion within a droplet and/or by vapour deposition of L-leucine. The powders are humidified at 0%, 44%, 65% and 75% of relative humidity and the changes in physical properties of the powders are investigated with dynamic vapour sorption analysis (DVS), a differential scanning calorimeter (DSC), and a scanning electron microscope (SEM). Visual observation show that all the coated particles preserve their structural integrity whereas uncoated salbutamol sulphate particles are unstable at 65% of relative humidity. The coating layer formed by diffusion performs best in terms of its physical stability against moisture and moisture-induced crystallization. The degree of crystallization of salbutamol in the as-prepared powders is within the range 24-35%. The maximum degree of crystallization after drying ranges from 55 to 73% when the salbutamol crystallizes with the aid of moisture. In addition to providing protection against moisture, the L-leucine coating also stabilizes the particle structure against heat at temperatures up to 250 degrees C. In order to preserve good flowability together with good physical stability, the best coating would contain two L-leucine layers, the inner layer being formed by diffusion (physical stability) and the outer layer by vapour deposition (flowability).

  9. Effects of volatile coatings on the morphology and optical detection of combustion-generated black carbon particles.

    SciTech Connect

    Bambha, Ray.; Dansson, Mark A; Schrader, Paul E.; Michelsen, Hope A.

    2013-09-01

    We have measured time-resolved laser-induced incandescence (LII) from combustion-generated mature soot extracted from a burner and (1) coated with oleic acid or (2) coated with oleic acid and then thermally denuded using a thermodenuder. The soot samples were size selected using a differential mobility analyser and characterized with a scanning mobility particle sizer, centrifugal particle mass analyser, and transmission electron microscope. The results demonstrate a strong influence of coatings particle morphology and on the magnitude and temporal evolution of the LII signal. For coated particles higher laser fluences are required to reach LII signal levels comparable to those of uncoated particles. This effect is predominantly attributable to the additional energy needed to vaporize the coating while heating the particle. LII signals are higher and signal decay rates are significantly slower for thermally denuded particles relative to coated or uncoated particles, particularly at low and intermediate laser fluences.

  10. Conducting polymer-coated corrosion resistant metallic bipolar plates for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Joseph, Shine

    2005-11-01

    addition to this, metal dissolution can contaminate the membrane electrode assembly (MEA) and can cause system failure. These problems can be solved by coating the aluminum and stainless steel alloys with corrosion resistant and conductive polymers such as polyaniline and polypyrrole. These polymers can be applied to the metallic substrates by various methods such as electrochemical deposition, spraying and painting. Corrosion and contact resistance of the coated plates were tested under fuel cell conditions and showed promising results. Coatings were characterized by microscopy, infrared spectroscopy (FTIR) and cyclic voltammetry.

  11. Analytical modeling of intumescent coating thermal protection system in a JP-5 fuel fire environment

    NASA Technical Reports Server (NTRS)

    Clark, K. J.; Shimizu, A. B.; Suchsland, K. E.; Moyer, C. B.

    1974-01-01

    The thermochemical response of Coating 313 when exposed to a fuel fire environment was studied to provide a tool for predicting the reaction time. The existing Aerotherm Charring Material Thermal Response and Ablation (CMA) computer program was modified to treat swelling materials. The modified code is now designated Aerotherm Transient Response of Intumescing Materials (TRIM) code. In addition, thermophysical property data for Coating 313 were analyzed and reduced for use in the TRIM code. An input data sensitivity study was performed, and performance tests of Coating 313/steel substrate models were carried out. The end product is a reliable computational model, the TRIM code, which was thoroughly validated for Coating 313. The tasks reported include: generation of input data, development of swell model and implementation in TRIM code, sensitivity study, acquisition of experimental data, comparisons of predictions with data, and predictions with intermediate insulation.

  12. A novel gas phase method for the combined synthesis and coating of pharmaceutical particles.

    PubMed

    Raula, Janne; Lähde, Anna; Kauppinen, Esko I

    2008-01-01

    A novel aerosol flow reactor method for the combined gas phase synthesis and coating of particles for drug delivery has been developed. As an example, micron-sized salbutamol sulfate particles were produced via droplet-to-particle conversion and in-situ coated by the physical vapor deposition (PVD) of L-leucine vapor. During the deposition, L-leucine vapor crystallized on the surfaces of amorphous salbutamol particles. The size of L-leucine crystallites increased with increasing vapor concentration of L-leucine. The salbutamol particles with rough L-leucine surfaces exhibited good flowability enabling to them to be dispersed into air flow without the delivery aid of coarse lactose carriers. The fraction of particles smaller than 5 micrometers varied between 0.35 and 0.48 when dispersed into 60 l/min air flow having a jet Reynolds number of 30700. When the coated fine particles were blended with lactose carriers, the fine particle fraction was as high as 90%. The L-leucine coating also improved the stability of salbutamol particles when stored at 45% relative humidity atmosphere.

  13. Understanding Particle Defect Transport in an Ultra-Clean Sputter Coating Process

    SciTech Connect

    Walton, C; Kearney, P; Folta, J; Sweeney, D; Mirkarimi, P

    2003-03-24

    Low-defect mask blanks remain a key technical challenge to Extreme Ultraviolet Lithography (EUVL). The mask blank is ion-beam sputter-coated with an 81-layer Mo/Si multilayer stack for high reflectance at {lambda} = 13.4nm. The current mask coating process can achieve a median added defect level of 0.05 defects/cm{sup 2} (12 added defects 90nm or larger on a 200mm Si-wafer test substrate), but this must be reduced by about a factor of 10 to meet mask cost requirements for EUVL. To further reduce the particle defect level, we have studied pathways for particle transport, using test particles and particles native to the coating process, and combined the results into a computational model of particle transport in an ion-beam sputter system. At process pressure, gas drag is negligible for particles above 100nm, so particles travel ballistically until they hit a surface. Bounce from chamber walls allows particles to reach all surfaces in the chamber if they have initial velocities above {approx}100m/s. The ion beam has sufficient momentum to entrain slower particles and accelerate them toward the sputter target, where some can bounce to the substrate. The model shows preliminary agreement with experimental defect distributions on witness wafers at various positions within the coating chamber.

  14. Microstructure evolution of a ZrC coating layer in TRISO particles during high-temperature annealing

    NASA Astrophysics Data System (ADS)

    Kim, Daejong; Chun, Young Bum; Ko, Myeong Jin; Lee, Hyeon-Geun; Cho, Moon-Sung; Park, Ji Yeon; Kim, Weon-Ju

    2016-10-01

    The influence of high-temperature annealing on the microstructure of zirconium carbide (ZrC) was investigated in relation to its application as a coating layer of a nuclear fuel in a very high temperature gas cooled reactor. ZrC was deposited as a constituent coating layer of TRISO coated particles by a fluidized bed chemical vapor deposition method using a ZrCl4-CH4-Ar-H2 system. The grain growth of ZrC during high-temperature annealing was strongly influenced by the co-deposition of free carbon. Sub-stoichiometric ZrC coatings have experienced a significant grain growth during high-temperature annealing at 1800 °C and 1900 °C for 1 h. On the other hand, a dual phase of stoichiometric ZrC and free carbon experienced little grain growth. It was revealed that the free carbon of the as-deposited ZrC was primarily distributed within the ZrC grains but was redistributed to the grain boundaries after annealing. Consequently, carbon at the grain boundary retarded the grain growth of ZrC. Electron backscatter diffraction (EBSD) results showed that as-deposited ZrC had (001) a preferred orientation that kept its favored direction after significant grain growth during annealing. The hardness slightly decreased as the grain growth progressed.

  15. Laboratory Evaluation of Light Obscuration Particle Counter Contamination Limits for Aviation Fuel

    DTIC Science & Technology

    2015-11-01

    matter in aviation fuels. Specifically, free water contamination in jet fuel cannot exceed 10 parts per million (PPM) (1) and particulate matter ...free water and/or particulate matter in aviation fuel was published. In August 2012 EI published the first edition of EI 1570 Handbook on electronic...the particulate matter of fuels using light obscuration particle counters; IP 564 – Determination of the level of cleanliness of aviation turbine

  16. Effect of particle in-flight behavior on the composition of thermal barrier coatings

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Bai, Y.; Tang, J. J.; Liu, K.; Ding, C. H.; Yang, J. F.; Han, Z. H.

    2013-12-01

    In this work, 6 to 11 mol% YO1.5-stabilized zirconia (YSZ) coatings were deposited by supersonic and conventional atmospheric plasma spraying. During spraying, the surface temperature and velocity of in-flight particles were monitored by Spray Watch 2i on-line system. The phase composition of as-sprayed coatings was analyzed by X-ray diffractometry (XRD). Lattice parameters, tetragonality and the content of YO1.5 (mol%) of as-sprayed coatings were calculated according to the position of (0 0 4) and (4 0 0) diffraction peaks. It was found that the as-sprayed coatings were composed of metastable non-transformable tetragonal phase (t‧). However, the amount of YO1.5 (mol%) in the as-sprayed coatings decreased with the increase of melting index of in-flight particles due to the partial evaporation of YO1.5 during spraying.

  17. Dielectric coating of iron particles by electrostatic colloidal deposition

    NASA Astrophysics Data System (ADS)

    Kim, Daniel

    Iron is a soft magnetic material widely used in electric motors, generators, and transformers because they demand high permeability and low core loss. The main goal of this project is to develop a commercially viable coating of iron powders for press-and-sinter processing that would enable higher firing temperatures to anneal out magnetic defects, while maintaining high electrical resistivity (˜10,000 muO-cm) and high iron density (>90 %). An alumina-modified colloidal silica (LUDOX CL), was used in early work to make Fe (-)/SiO2 (+) in a wet-pressed route. The highest relative density and resistivity measurements for a wet-pressing route were 87 % and 7300 +/- 1000 muO-cm respectively. Dry-pressed route is favorable over wet-pressed route because it can be commercially viable. About 100-fold increase in resistivity (860,000 muO-cm) was obtained compared to the wet-pressed route, with only a small decrease in density (1 - 2 %). A study was conducted to explore the separate, and possibly interactive, effects of micro-alumina particulate (Sumitomo AKP-50, 0.2 mum) and lubricant (Kenolube, a proprietary metal soap-wax composite lube). Reducing the LUDOX CL, high shear mixing using a coffee grinder, and multimodal packing were studied to improve density. Only 10 % reduction of LUDOX CL dropped the resistivity by over two orders of magnitude with the same relative density. High shear mixing and multimodal packing had little effects to increase density. An unmodified colloidal silica (LUDOX TM) was also explored to make Fe (+) /SiO2 (-) and resistivity of 120,000 muO-cm and 80 % density were obtained. Addition of cationic polyelectrolyte, polydiallyldimethyl-ammonium chloride (PDADMAC) was studied to provide stronger adhesion between LUDOX TM and surface of iron particles. Reducing the amount of LUDOX TM in PDADMAC showed relative density greater than 90 % but resistivity measurements were less than 1500 iU-cm.

  18. Low-friction coatings for air bearings in fuel cell air compressors

    SciTech Connect

    Ajayi, O. O.; Fenske, G. R.; Erdemir, A.; Woodford, J.; Sitts, J.; Elshot, K.; Griffey, K.

    2000-01-06

    In an effort to reduce fuel consumption and emissions, hybrid vehicles incorporating fuel cell systems are being developed by automotive manufacturers, their suppliers, federal agencies (specifically, the US Department of Energy) and national laboratories. The fuel cell system will require an air management subsystem that includes a compressor/expander. Certain components in the compressor will require innovative lubrication technology in order to reduce parasitic energy losses and improve their reliability and durability. One such component is the air bearing for air turbocompressors designed and fabricated by Meruit, Inc. Argonne National Laboratory recently developed a carbon-based coating with low friction and wear attributes; this near-frictionless-carbon (NFC) coating is a potential candidate for use in turbocompressor air bearings. The authors present here an evaluation of the Argonne coating for air compressor thrust bearings. With two parallel 440C stainless steel discs in unidirectional sliding contact, the NFC reduced the frictional force four times and the wear rate by more than two orders of magnitude. Wear mechanism on the uncoated surface involved oxidation and production of iron oxide debris. Wear occurred on the coated surfaces primarily by a polishing mechanism.

  19. Direct high-resolution alpha spectrometry from nuclear fuel particles in an outdoor air sample.

    PubMed

    Pöllänen, R; Siiskonen, T

    2008-01-01

    The potential use of direct high-resolution alpha spectrometry to identify the presence of transactinium elements in air samples is illustrated in the case when alpha-particle-emitting radionuclides are incorporated in nuclear fuel particles. Alpha particle energy spectra are generated through Monte Carlo simulations assuming a nuclide composition similar to RBMK (Chernobyl) nuclear fuel. The major alpha-particle-emitting radionuclides, in terms of activity, are 242Cm, 239Pu and 240Pu. The characteristics of the alpha peaks are determined by fuel particle properties as well as the type of the air filter. It is shown that direct alpha spectrometry can be readily applied to membrane filter samples containing nuclear fuel particles when rapid nuclide identification is of relevance. However, the development of a novel spectrum analysis code is a prerequisite for unfolding complex alpha spectra.

  20. Numerical analysis of Al coating using different particle shape in LPCS

    NASA Astrophysics Data System (ADS)

    Yusof, S. N. A.; Manap, A.; Afandi, N. F.

    2016-03-01

    Cold spray (CS) is a unique spraying process where the spray materials are not melted in a spray gun. Instead, the particles are kinetically deposited on the substrate at low temperature using compressed gas. This study investigates the deposition behaviour of different particle shape of Al coating using low pressure cold sprayed (LPCS) through smoothed particle hydrodynamics (SPH) simulations, which are achieved by modelling the multiple particle impacts on Al substrate. The impact of Al particle on the Al substrate is analysed by evaluating the shape of deformation, porosity between particle, and effect of stress on the substrate. The results show that the irregular particle shapes (horizontal and vertical ellipse) tend to detach the bonded particle from the substrate and thus increase the potential risk of high tensile stress. That is really harmful to the coating quality, which never happens for spherical particle. Deposition using irregular particle exhibits tensile stress at the depth coating, whereas spherical particle exhibits compressive stress. Compressive stress is generally ensure a longer component life due to their positive effect on the fatigue life and wear resistance application.

  1. Effects of coating of dicarboxylic acids on the mass-mobility relationship of soot particles.

    PubMed

    Xue, Huaxin; Khalizov, Alexei F; Wang, Lin; Zheng, Jun; Zhang, Renyi

    2009-04-15

    Atandem differential mobility analyzer (TDMA) and a differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) have been employed to study morphology and hygroscopicity of soot aerosol internally mixed with dicarboxylic acids. The effective densities, fractal dimensions, and dynamic shape factors of soot particles before and after coating with succinic and glutaric acids are determined. Coating of soot with succinic acid results in a significant increase in the particle mobility diameter, mass, and effective density, but these properties recover to their initial values once succinic acid is removed by heating, suggesting that no restructuring of the soot core occurs. This conclusion is also supported from the observation of similar fractal dimensions and dynamic shape factors for fresh and coated/heated soot aggregates. Also, no change is observed when succinic acid-coated aggregates are cycled through elevated relative humidity (5% to 90% to 5% RH) below the succinic acid deliquescence point. When soot is coated with glutaric acid, the particle mass increases, but the mobility diameter shrinks by 10-40%. Cycling the soot aerosol coated with glutaric acid through elevated relative humidity leads to an additional mass increase, indicating that condensed water remains within the coating even at low RH. The fractal dimension of soot particles increases after coating and remains high when glutaric acid is removed by heating. The dynamic shape factor of glutaric acid-coated and heated soot is significantly lower than that of fresh soot, suggesting a significant restructuring of the soot agglomerates by glutaric acid. The results imply that internal mixing of soot aerosol during atmospheric aging leads to changes in hygroscopicity, morphology, and effective density, which likely modify their effects on direct and indirect climate forcing and deposition in the human respiratory system.

  2. Carbon monoxide formation in UO 2 kerneled HTR fuel particles containing oxygen getters

    NASA Astrophysics Data System (ADS)

    Proksch, E.; Strigl, A.; Nabielek, H.

    1986-06-01

    Mass spectrometric measurements of CO in irradiated UO 2 kerneled HTR fuel particles containing various oxygen getters are summarized and evaluated. Uranium carbide addition in the 3 to 15% range reduces the CO release by factors between 25 and 80, up to burn-up levels as high as 70% FIMA. Unintentional gettering by SiC in TRISO coated particles with failed inner pyrocarbon layers results in CO reduction factors between 15 and 110. For ZrC, only somewhat ambiguous results have been obtained; most likely, ZrC results in CO reduction by a factor of about 40. Ce 2O 3 and La 2O 3 seem to be somewhat less effective than the three carbides; for Ce 2O 3, reduction factors between 3 and 15 have been found. However, these results are possibly incorrect due to premature oxidation of the getter already during fabrication. Addition of SiO 2 + Al 2O 3 has no influence on CO release at all.

  3. Production of CO during burnup of (Th, U)O 2 kerneled HTR fuel particles

    NASA Astrophysics Data System (ADS)

    Proksch, Emil; Strigl, Anton; Nabielek, Heinz

    1985-10-01

    The CO content of irradiated (Th, U)O 2 kerneled HTR fuel particles has been measured by mass spectrometry. An evaluation of all the data thus obtained showed that the oxygen release, O/f (atoms per fission), during irradiation is governed by thermodynamic equilibrium; O/f is a function of the irradiation temperature T(K), the initial Th/U-235 ratio N, and the burnup F (fissions per initial heavy metal atom). Within the limits of 1073 < T < 2273, 4 < N <50, and 0.04 < F < 0.17, the oxygen release can be represented by the expression log 10O/f = 0.96 - 4420/T + 0.4 log 10N + 0.3 log 10F . The attainment of equilibrium proceeds rather slowly; at 1473 K it takes about 130 h to reach 99% of the equilibrium value. Coated particles which had undergone large fission-product losses showed significantly increased oxygen release values.

  4. New generation nuclear fuel structures: dense particles in selectively soluble matrix

    SciTech Connect

    Sickafus, Kurt E; Devlin, David J; Jarvinen, Gordon D; Patterson, Brian M; Pattillo, Steve G; Valdez, James; Phillips, Jonathan

    2009-01-01

    We have developed a technology for dispersing sub-millimeter sized fuel particles within a bulk matrix that can be selectively dissolved. This may enable the generation of advanced nuclear fuels with easy separation of actinides and fission products. The large kinetic energy of the fission products results in most of them escaping from the sub-millimeter sized fuel particles and depositing in the matrix during burning of the fuel in the reactor. After the fuel is used and allowed to cool for a period of time, the matrix can be dissolved and the fission products removed for disposal while the fuel particles are collected by filtration for recycle. The success of such an approach would meet a major goal of the GNEP program to provide advanced recycle technology for nuclear energy production. The benefits of such an approach include (1) greatly reduced cost of the actinide/fission product separation process, (2) ease of recycle of the fuel particles, and (3) a radiation barrier to prevent theft or diversion of the recycled fuel particles during the time they are re-fabricated into new fuel. In this study we describe a method to make surrogate nuclear fuels of micrometer scale W (shell)/Mo (core) or HfO2 particles embedded in an MgO matrix that allows easy separation of the fission products and their embedded particles. In brief, the method consists of physically mixing W-Mo or hafnia particles with an MgO precursor. Heating the mixture, in air or argon, without agitation, to a temperature is required for complete decomposition of the precursor. The resulting material was examined using chemical analysis, scanning electron microscopy, X-ray diffraction and micro X-ray computed tomography and found to consist of evenly dispersed particles in an MgO + matrix. We believe this methodology can be extended to actinides and other matrix materials.

  5. Enhancement and degradation of the R2* relaxation rate resulting from the encapsulation of magnetic particles with hydrophilic coatings.

    PubMed

    de Haan, Hendrick W; Paquet, Chantal

    2011-12-01

    The effects of including a hydrophilic coating around the particles are studied across a wide range of particle sizes by performing Monte Carlo simulations of protons diffusing through a system of magnetic particles. A physically realistic methodology of implementing the coating by cross boundary jump scaling and transition probabilities at the coating surface is developed. Using this formulation, the coating has three distinct impacts on the relaxation rate: an enhancement at small particle sizes, a degradation at intermediate particle sizes, and no effect at large particles sizes. These varied effects are reconciled with the underlying dephasing mechanisms by using the concept of a full dephasing zone to present a physical picture of the dephasing process with and without the coating for all sizes. The enhancement at small particle sizes is studied systemically to demonstrate the existence of an optimal ratio of diffusion coefficients inside/outside the coating to achieve maximal increase in the relaxation rate.

  6. The self-sense monitoring of coating wear by in situ SiO2-coated SrAl2O4:Eu2+,Dy3+ luminescent particles

    NASA Astrophysics Data System (ADS)

    LI, Wensheng; He, Ling; Hu, Chunxia; Tian Yang, Xiao

    2017-05-01

    Monitoring of coating health was achieved by embedding sensor materials SrAl2O4:Eu2+,Dy3+ in tribological coatings, and luminescence spectra of sensor materials were used for damage sensing by monitoring the intensity of the spectra. When the light emitting from coating disappeared, it indicated the coating wearied off and the substrate exposed. But emission intensity of the SrAl2O4:Eu2+,Dy3+ in tribological coating was quenched in preparation process which will weaken the effect of coating instructions. In this work, SiO2-coated SrAl2O4:Eu2+,Dy3+ were coupled with Cu-14Al-X alloy powders to form sensor composite coating by supersonic plasma spraying. The composite coatings before and after SiO2-coating were compared of phase composition, microstructure, luminescence properties and tribological performance. The composite coating shows not only good resistance to wear but also exhibits strong green light emitting under UV light. The SiO2-coating could prevent phosphors quenching due to high temperature in the supersonic plasma spraying process, and could repair the wear surface. The composite coating with SiO2-coated SrAl2O4:Eu2+,Dy3+ particles had very stable friction coefficient, When the coating ratio of SiO2 was 10% for SrAl2O4:Eu2+,Dy3+ particles, the luminescent properties and friction property of composite was optimal.

  7. Dynamics of coalescence and spreading of liquid polymeric particles during coating formation

    NASA Astrophysics Data System (ADS)

    Fedyaev, V. L.; Galimov, E. R.; Galimova, N. Ya; Gimranov, I. R.; Siraev, A. R.

    2017-01-01

    Processes of agglutination, coalescence and spreading of polymeric powder particles during coating formation are considered using methods of mathematical modeling. The relationships to evaluate time of particles agglutination, velocity of coalescence and spreading of material on the surface of a treated body are given. Recommendations on intensification of the given technological stages are presented.

  8. Fission-product retention in HTGR fuels

    SciTech Connect

    Homan, F.J.; Kania, M.J.; Tiegs, T.N.

    1982-01-01

    Retention data for gaseous and metallic fission products are presented for both Triso-coated and Biso-coated HTGR fuel particles. Performance trends are established that relate fission product retention to operating parameters, such as temperature, burnup, and neutron exposure. It is concluded that Biso-coated particles are not adequately retentive of fission gas or metallic cesium, and Triso-coated particles which retain cesium still lose silver. Design implications related to these performance trends are identified and discussed.

  9. Granulation of core particles suitable for film coating by agitation fluidized bed I. Optimum formulation for core particles and development of a novel friability test method.

    PubMed

    Hamashita, Tomohiro; Nakagawa, Yasuo; Aketo, Takao; Watano, Satoru

    2007-08-01

    To prepare powdered medicines without bitter taste, film coating is required to cover the surface of core particles. In this study, effect of formulation and operating conditions of agitation fluidized bed on the core particle properties was investigated. In order to prevent breakage of the core particles during coating process, which sometimes causes variation of drug dissolution rate, addition of maltose syrup powder during the formulation process of the core particles was investigated. Also, a method for friability test in which the core particles were subjected to strong impact was proposed to evaluate strength of the core particles. The friability of the core particles determined by this test method correlated well with the actual friability of the particles during the coating process. Based on this result, we confirmed this novel friability test method could predict the core particle endurance during the coating process.

  10. The effect of impaction and a bioceramic coating on bone ingrowth in porous titanium particles

    PubMed Central

    2011-01-01

    Background and purpose Porous titanium (Ti) particles can be impacted like cancellous allograft bone particles, and may therefore be used as bone substitute in impaction grafting. We evaluated the effect of impaction and of a thin silicated biphasic calcium phosphate coating on osteoconduction by Ti particles. Methods The bone conduction chamber of Aspenberg was used in goats and filled with various groups of coated or uncoated small Ti particles (diameter 1.0–1.4 mm). Impacted allograft bone particles and empty chambers were used in control groups. Fluorochromes were administered at 4, 8, and 12 weeks. Maximum bone ingrowth distance was evaluated by histomorphometric analysis. Results Histology of Ti particle graft cylinders showed a dense matrix with narrow inter-particle and intra-particle pores (< 100 μm), occluding the lumen of the bone chamber. Bone ingrowth distances gradually increased with time in all groups. Maximum bone ingrowth distance was higher in originally empty chambers than those with allograft bone particles (p = 0.01) and Ti particles (p < 0.001). Maximum bone ingrowth in allograft bone particles was higher than in all Ti groups (p ≤ 0.001). Impaction reduced osteoconduction and the coating partially compensated for the negative effect of impaction, but these differences were not statistically significant. No osteolytic reactions were found. Interpretation Osteoconduction in the bone conduction chamber was reduced more by the insertion of small Ti particles than by insertion of small allograft bone particles. The osteoconductive potential of porous Ti particles should be studied further with larger-sized particles, which may allow bone ingrowth after impaction through larger inter-particle pores. PMID:21504310

  11. Self-assembly of graphene oxide coated soft magnetic carbonyl iron particles and their magnetorheology

    SciTech Connect

    Zhang, W. L.; Choi, H. J.

    2014-05-07

    The surface of carbonyl iron (CI) microspheres was modified with graphene oxide (GO) as a coating material using 4-aminobenzoic acid as the grafting agent. The morphology, elemental composition, and magnetic properties of the GO-coated CI (GO/CI) particles were examined by scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry, respectively, confirming their composite formation. The magnetorheological (MR) performance of the GO/CI particle-based suspension was examined using a rotational rheometer connected to a magnetic field supply. The GO/CI particles suspension exhibited typical MR properties with increasing shear stress and viscosity depending on the applied magnetic field strength.

  12. Distinct element analysis of inter-particle coating variability in a batch seed coater

    NASA Astrophysics Data System (ADS)

    Pasha, Mehrdad; Ghadiri, Mojtaba; Gunadi, Alfeno; Piccione, Patrick M.

    2017-06-01

    Coating of particulate solids by a thin film layer is of interest in many industrial applications such as seed and tablet coating. In seed processing, seeds are commonly coated with a protective coating layer consisting of fertilisers and crop protection products. Rotary drum batch coaters are typically used for this purpose. The coater consists of a cylindrical vessel with a rotating spray disk in the centre, onto which the coating liquid is fed. The seeds are driven around the vessel by its rotating base, and are mixed by two baffles; one on either side of the vessel. In the present study, DEM simulations are used to analyse the seed coating process. Corn seed is used as a model material and its shape is captured using X-Ray micro-tomography (XRT). The shape is incorporated into the simulations by the clumping multiple spheres to form a particle assembly. The coating uniformity of the seeds is predicted by implementing a coating model, whereby the coating mechanism is represented in the DEM by considering that once a droplet contacts a corn seed, it is removed from the simulation and its mass is attributed to the coating mass of the corn seed. The distribution of mass of sprayed spheres on the corn seeds and the coefficient of variation are evaluated for a range of process conditions, such as spinning disk rotational speed, droplets size and baffle arrangement and designs. In addition to evaluation of coating uniformity of particles, the scale-up rules for rotary drum batch coaters are investigated and reported. The outcome provides guidelines on scale-up rules and improvement of coating uniformity for rotary batch seed coaters.

  13. Structure and electromagnetic properties of FeSiAl particles coated by MgO

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhou, Ting-dong

    2017-03-01

    FeSiAl particles with a layer of MgO surface coating have excellent soft magnetic and electromagnetic properties. In order to obtain the FeSiAl/MgO composites, Mg(OH)2 sol prepared by sol-gel process was well-mixed with FeSiAl flake particles, and then treated by calcination at 823 K in vacuum. The microstructural, morphological and electromagnetic parameters of FeSiAl/MgO particles were tested. Accordingly, the electromagnetic wave reflection loss in the frequency range of 0.5-18 GHz was calculated. The results show that the surface coating increases coercivity Hc and decreases complex permittivity, leading to a good impedance matching. When the coating amount was 7.5%, reflection loss of the composite particles can reach to -33 dB.

  14. Design colloidal particle morphology and self-assembly for coating applications

    DOE PAGES

    Jiang, Shan; Van Dyk, Antony; Maurice, Alvin; ...

    2017-05-04

    The progressive replacement of organic solvent-based coatings by waterborne latex polymer coatings has substantially renovated the coating industry, and generated huge environmental and health benefits. Today, on top of the continuing demand for higher performance and lower costs, the coating industry faces tighter regulation and higher sustainability standards. In addition, the new waterborne coatings have created unique opportunities and challenges in terms of fundamental understanding and research development. To address these challenges, polymer latex binders with diverse particle morphologies have been developed to improve coating performance. Furthermore, colloidal self-assembly has been utilized to help manufacturers make better paint with lessmore » cost. In this report, we review the recent progress in both fundamental study and industrial application in the context of developing new generation architectural coating materials. We introduce the basic concepts in coating materials and showcase several key technologies that have been implemented to improve coating performance. As a result, these technologies also represent the most important considerations in architectural coating design.« less

  15. Characterization of High-Velocity Single Particle Impacts on Plasma-Sprayed Ceramic Coatings

    NASA Astrophysics Data System (ADS)

    Kiilakoski, Jarkko; Lindroos, Matti; Apostol, Marian; Koivuluoto, Heli; Kuokkala, Veli-Tapani; Vuoristo, Petri

    2016-08-01

    High-velocity impact wear can have a significant effect on the lifetime of thermally sprayed coatings in multiple applications, e.g., in the process and paper industries. Plasma-sprayed oxide coatings, such as Cr2O3- and TiO2-based coatings, are often used in these industries in wear and corrosion applications. An experimental impact study was performed on thermally sprayed ceramic coatings using the High-Velocity Particle Impactor (HVPI) at oblique angles to investigate the damage, failure, and deformation of the coated structures. The impact site was characterized by profilometry, optical microscopy, and scanning electron microscopy (SEM). Furthermore, the connection between the microstructural details and impact behavior was studied in order to reveal the damage and failure characteristics at a more comprehensive level. Differences in the fracture behavior were found between the thermally sprayed Cr2O3 and TiO2 coatings, and a concept of critical impact energy is presented here. The superior cohesion of the TiO2 coating inhibited interlamellar cracking while the Cr2O3 coating suffered greater damage at high impact energies. The HVPI experiment has proven to be able to produce valuable information about the deformation behavior of coatings under high strain rates and could be utilized further in the development of wear-resistant coatings.

  16. Electromechanical characterization of individual micron-sized metal coated polymer particles

    SciTech Connect

    Bazilchuk, Molly; Kristiansen, Helge; Pettersen, Sigurd Rolland; Zhang, Zhiliang; He, Jianying

    2016-06-28

    Micron-sized polymer particles with nanoscale metal coatings are essential in conductive adhesives for electronics assembly. The particles function in a compressed state in the adhesives. The link between mechanical properties and electrical conductivity is thus of the utmost importance in the formation of good electrical contact. A custom flat punch set-up based on nanoindentation has been developed to simultaneously deform and electrically probe individual particles. The set-up has a sufficiently low internal resistance to allow the measurement of sub-Ohm contact resistances. Additionally, the set-up can capture mechanical failure of the particles. Combining this data yields a fundamental understanding of contact behavior. We demonstrate that this method can clearly distinguish between particles of different sizes, with different thicknesses of metal coating, and different metallization schemes. The technique provides good repeatability and physical insight into the behavior of these particles that can guide adhesive design and the optimization of bonding processes.

  17. Electromechanical characterization of individual micron-sized metal coated polymer particles

    NASA Astrophysics Data System (ADS)

    Bazilchuk, Molly; Pettersen, Sigurd Rolland; Kristiansen, Helge; Zhang, Zhiliang; He, Jianying

    2016-06-01

    Micron-sized polymer particles with nanoscale metal coatings are essential in conductive adhesives for electronics assembly. The particles function in a compressed state in the adhesives. The link between mechanical properties and electrical conductivity is thus of the utmost importance in the formation of good electrical contact. A custom flat punch set-up based on nanoindentation has been developed to simultaneously deform and electrically probe individual particles. The set-up has a sufficiently low internal resistance to allow the measurement of sub-Ohm contact resistances. Additionally, the set-up can capture mechanical failure of the particles. Combining this data yields a fundamental understanding of contact behavior. We demonstrate that this method can clearly distinguish between particles of different sizes, with different thicknesses of metal coating, and different metallization schemes. The technique provides good repeatability and physical insight into the behavior of these particles that can guide adhesive design and the optimization of bonding processes.

  18. Enhanced transport of Si-coated nanoscale zero-valent iron particles in porous media.

    PubMed

    HonetschlÄgerová, Lenka; Janouškovcová, Petra; Kubal, Martin

    2016-01-01

    Laboratory column experiments were conducted to evaluate the effect of previously described silica coating method on the transport of nanoscale zero-valent iron (nZVI) in porous media. The silica coating method showed the potential to prevent the agglomeration of nZVI. Transport experiments were conducted using laboratory-scale sand-packed columns at conditions that were very similar of natural groundwater. Transport properties of non-coated and silica-coated nZVI are investigated in columns of 40 cm length, which were filled with porous media. A suspension was injected in three different Fe particle concentrations (100, 500, and 1000 mg/L) at flow 5  mL/min. Experimental results were compared using nanoparticle attachment efficiency and travel distances which were calculated by classical particle filtration theory. It was found that non-coated particles were essentially immobile in porous media. In contrast, silica-coated particles showed significant transport distances at the tested conditions. Results of this study suggest that silica can increase nZVI mobility in the subsurface.

  19. Nanocrystalline ceria coatings on solid oxide fuel cell anodes: the role of organic surfactant pretreatments on coating microstructures and sulfur tolerance

    PubMed Central

    Wu, Chieh-Chun; Tang, Ling

    2014-01-01

    Summary Treatments with organic surfactants, followed by the deposition of nanocrystalline ceria coatings from aqueous solution, were applied to anodes of solid oxide fuel cells. The cells were then operated in hydrogen/nitrogen fuel streams with H2S contents ranging from 0 to 500 ppm. Two surfactant treatments were studied: immersion in dodecanethiol, and a multi-step conversion of a siloxy-anchored alkyl bromide to a sulfonate functionality. The ceria coatings deposited after the thiol pretreatment, and on anodes with no pretreatment, were continuous and uniform, with thicknesses of 60–170 nm and 100–140 nm, respectively, and those cells exhibited better lifetime performance and sulfur tolerance compared to cells with untreated anodes and anodes with ceria coatings deposited after the sulfonate pretreatment. Possible explanations for the effects of the treatments on the structure of the coatings, and for the effects of the coatings on the performance of the cells, are discussed. PMID:25383282

  20. Volatile organic compounds (VOCs) in surface coating materials: Their compositions and potential as an alternative fuel.

    PubMed

    Dinh, Trieu-Vuong; Choi, In-Young; Son, Youn-Suk; Song, Kyu-Yong; Sunwoo, Young; Kim, Jo-Chun

    2016-03-01

    A sampling system was designed to determine the composition ratios of VOCs emitted from 31 surface coating materials (SCMs). Representative architectural, automotive, and marine SCMs in Korea were investigated. Toluene, ethylbenzene, and xylene were the predominant VOCs. The VOC levels (wt%) from automotive SCMs were significantly higher than those from architectural and marine paints. It was found that target SCMs comprised mainly VOCs with 6-10 carbon atoms in molecules, which could be adsorbed by activated carbon. The saturated activated carbon which had already adsorbed toluene, ethylbenzene, and m-xylene was combusted. The saturated activated carbon was more combustible than new activated carbon because it comprised inflammable VOCs. Therefore, it could be an alternative fuel when using in a "fuelization system". To use the activated carbon as a fuel, a control technology of VOCs from a coating process was also designed and introduced.

  1. Enhancement of cell performance using a gadolinium strontium cobaltite coated cathode in molten carbonate fuel cells

    NASA Astrophysics Data System (ADS)

    Song, Shin Ae; Jang, Seong-Cheol; Han, Jonghee; Yoon, Sung Pil; Nam, Suk Woo; Oh, In-Hwan; Lim, Tae-Hoon

    To enhance cathode performance, gadolinium strontium cobaltite (Gd 0.6Sr 0.4CoO 3, GSC) is coated onto a porous Ni plate by a vacuum suction method, for use as the cathode in molten carbonate fuel cells (MCFCs). GSC is a mixed ionic and electronic conductor (MIEC) material, and thus has high electronic conductivity and catalytic activity at low temperatures. The electrode performance of the GSC-coated cathode is examined by various methods, such as single cell operation and electrochemical impedance spectroscopy (EIS). At 600 °C, the performance of a single cell using a GSC-coated cathode is 0.813 V. This result is very surprising given that the performance of an uncoated conventional cathode is 0.69 V. Impedance analysis confirms that a dramatic decrease in the charge transfer resistance after GSC coating is primarily responsible for the cell enhancement at low temperature. The reaction orders for O 2 and CO 2 at uncoated and GSC-coated cathodes are also examined via a symmetric cell test, to identify the reaction mechanism of oxygen reduction. The peroxide mechanism, which is known to be a fast reaction, is predominant for the GSC-coated cathode at low temperatures, whereas the superoxide mechanism is predominant for the uncoated cathode.

  2. Mechanical characterization of oxide coating-interconnect interfaces for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Akanda, Sajedur R.; Walter, Mark E.; Kidner, Neil J.; Seabaugh, Matthew M.

    2012-07-01

    This paper reports on the characterization of interfaces between oxide coatings and metallic interconnects that are used in planar solid oxide fuel cells. With the reduction of operating temperatures to 800 °C, it is possible to replace ceramic interconnects with less expensive stainless steels. However, when incorporating chromia-forming metallic interconnects, steps must be taken to inhibit chromium poisoning. One approach to prevent chromium poisoning, is to deposit dense, protective coatings, such as manganese cobalt spinel oxide (MCO). The brittle nature of MCO makes it susceptible to damage under mechanical and thermal stresses during operation. A four point bend experiment is designed to assess the strength and adhesion of reduced and oxidized coatings deposited on SS441 or Crofer interconnects. Resulting tensile cracking patterns on the convex side of bend specimen are used to quantify the interfacial shear strength with a shear lag model. Using energy based fracture mechanics, interfacial fracture energy is calculated from the strain at the onset of coating spallation. Scanning electron microscopy images of the cracked coating surfaces are processed to analyze the failure mechanisms, crack spacing and spalled areas. At 3% strain, the weakest interface is found in the Crofer system with the oxidized coating.

  3. Study of the effects of fuel vortex film cooling on high temperature coating durability

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A report on the effects of fuel vortex film cooling on high temperature coating durability is presented. The program evaluated candidate high temperature oxidation resistant reaction control system engine thrust chamber material. As a result of the evaluation, the current and future programs may be optimized from the materials standpoint. Engine firing data for the evaluation of one material system is generated. The subjects considered are: (1) screening of materials, (2) thrust chamber fabrication, (3) engine testing, and (4) analysis of the data.

  4. RESULTS OF TESTS TO DEMONSTRATE A SIX-INCH-DIAMETER COATER FOR PRODUCTION OF TRISO-COATED PARTICLES FOR ADVANCED GAS REACTOR EXPERIMENTS

    SciTech Connect

    Charles M Barnes

    2008-09-01

    The Next Generation Nuclear Plant (NGNP)/Advanced Gas Reactor (AGR) Fuel Development and Qualification Program includes a series of irradiation experiments in Idaho National Laboratory’s (INL’s) Advanced Test Reactor. TRISOcoated particles for the first AGR experiment, AGR-1, were produced at Oak Ridge National Laboratory (ORNL) in a two inch diameter coater. A requirement of the NGNP/AGR Program is to produce coated particles for later experiments in coaters more representative of industrial scale. Toward this end, tests have been performed by Babcock and Wilcox (B&W) in a six-inch diameter coater. These tests are expected to lead to successful fabrication of particles for the second AGR experiment, AGR-2. While a thorough study of how coating parameters affect particle properties was not the goal of these tests, the test data obtained provides insight into process parameter/coated particle property relationships. Most relationships for the six-inch diameter coater followed trends found with the ORNL two-inch coater, in spite of differences in coater design and bed hydrodynamics. For example the key coating parameters affecting pyrocarbon anisotropy were coater temperature, coating gas fraction, total gas flow rate and kernel charge size. Anisotropy of the outer pyrolytic carbon (OPyC) layer also strongly correlates with coater differential pressure. In an effort to reduce the total particle fabrication run time, silicon carbide (SiC) was deposited with methyltrichlorosilane (MTS) concentrations up to 3 mol %. Using only hydrogen as the fluidizing gas, the high concentration MTS tests resulted in particles with lower than desired SiC densities. However when hydrogen was partially replaced with argon, high SiC densities were achieved with the high MTS gas fraction.

  5. RESULTS OF TESTS TO DEMONSTRATE A SIX-INCH DIAMETER COATER FOR PRODUCTION OF TRISO-COATED PARTICLES FOR ADVANCED GAS REACTOR EXPERIMENTS

    SciTech Connect

    Douglas W. Marshall

    2008-09-01

    The Next Generation Nuclear Plant (NGNP)/Advanced Gas Reactor (AGR) Fuel Development and Qualification Program includes a series of irradiation experiments in Idaho National Laboratory's (INL's) Advanced Test Reactor. TRISOcoated particles for the first AGR experiment, AGR-1, were produced at Oak Ridge National Laboratory (ORNL) in a twoinch diameter coater. A requirement of the NGNP/AGR Program is to produce coated particles for later experiments in coaters more representative of industrial scale. Toward this end, tests have been performed by Babcock and Wilcox (B&W) in a six-inch diameter coater. These tests are expected to lead to successful fabrication of particles for the second AGR experiment, AGR-2. While a thorough study of how coating parameters affect particle properties was not the goal of these tests, the test data obtained provides insight into process parameter/coated particle property relationships. Most relationships for the six-inch diameter coater followed trends found with the ORNL two-inch coater, in spite of differences in coater design and bed hydrodynamics. For example the key coating parameters affecting pyrocarbon anisotropy were coater temperature, coating gas fraction, total gas flow rate and kernel charge size. Anisotropy of the outer pyrolytic carbon (OPyC) layer also strongly correlates with coater differential pressure. In an effort to reduce the total particle fabrication run time, silicon carbide (SiC) was deposited with methyltrichlorosilane (MTS) concentrations up to 3 mol %. Using only hydrogen as the fluidizing gas, the high concentration MTS tests resulted in particles with lower than desired SiC densities. However when hydrogen was partially replaced with argon, high SiC densities were achieved with the high MTS gas fraction.

  6. Effects of sulfuric acid and ammonium sulfate coatings on the ice nucleation properties of kaolinite particles

    NASA Astrophysics Data System (ADS)

    Eastwood, Michael L.; Cremel, Sebastien; Wheeler, Michael; Murray, Benjamin J.; Girard, Eric; Bertram, Allan K.

    2009-01-01

    The onset conditions for ice nucleation on H2SO4 coated, (NH4)2SO4 coated, and uncoated kaolinite particles at temperatures ranging from 233 to 246 K were studied. We define the onset conditions as the relative humidity and temperature at which the first ice nucleation event was observed. Uncoated particles were excellent ice nuclei; the onset relative humidity with respect to ice (RHi) was below 110% at all temperatures studied, consistent with previous measurements. H2SO4 coatings, however, drastically altered the ice nucleating ability of kaolinite particles, increasing the RHi required for ice nucleation by approximately 30%, similar to the recent measurements by Möhler et al. [2008b]. (NH4)2SO4 coated particles were poor ice nuclei at 245 K, but effective ice nuclei at 236 K. The differences between H2SO4 and (NH4)2SO4 coatings may be explained by the deliquescence and efflorescence properties of (NH4)2SO4. These results support the idea that emissions of SO2 and NH3 may influence the ice nucleating properties of mineral dust particles.

  7. Self-assembling particle-siloxane coatings for superhydrophobic concrete.

    PubMed

    Flores-Vivian, Ismael; Hejazi, Vahid; Kozhukhova, Marina I; Nosonovsky, Michael; Sobolev, Konstantin

    2013-12-26

    We report here, for the first time in the literature, a method to synthesize hydrophobic and superhydrophobic concrete. Concrete is normally a hydrophilic material, which significantly reduces the durability of concrete structures and pavements. To synthesize water-repellent concrete, hydrophobic emulsions were fabricated and applied on portland cement mortar tiles. The emulsion was enriched with the polymethyl-hydrogen siloxane oil hydrophobic agent as well as metakaolin (MK) or silica fume (SF) to induce the microroughness and polyvinyl alcohol (PVA) fibers to create hierarchical surfaces. Various emulsion types were investigated by using different mixing procedures, and single- and double-layer hydrophobic coatings were applied. The emulsions and coatings were characterized with optical microscope and scanning electron microscope (SEM), and their wetting properties, including the water contact angle (CA) and roll-off angle, were measured. A theoretical model for coated and non-coated concrete, which can be generalized for other types of materials, was developed to predict the effect of surface roughness and composition on the CA. An optimized distance between the aggregates was found where the CA has the highest value. The maximal CA measured was 156° for the specimen with PVA fibers treated with MK based emulsion. Since water penetration is the main factor leading to concrete deterioration, hydrophobic water-repellent concretes have much longer durability then regular concretes and can have a broad range of applications in civil and materials engineering.

  8. Ice nucleation and droplet formation by bare and coated soot particles

    NASA Astrophysics Data System (ADS)

    Friedman, Beth; Kulkarni, Gourihar; BeráNek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

    2011-09-01

    We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied in order to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone in order to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253 K and 243 K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233 K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles comparable to those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233 K and 253 K.

  9. A highly durable fuel cell electrocatalyst based on double-polymer-coated carbon nanotubes

    PubMed Central

    Berber, Mohamed R.; Hafez, Inas H.; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-01-01

    Driven by the demand for the commercialization of fuel cell (FC) technology, we describe the design and fabrication of a highly durable FC electrocatalyst based on double-polymer-coated carbon nanotubes for use in polymer electrolyte membrane fuel cells. The fabricated electrocatalyst is composed of Pt-deposited polybenzimidazole-coated carbon nanotubes, which are further coated with Nafion. By using this electrocatalyst, a high FC performance with a power density of 375 mW/cm2 (at 70 ˚C, 50% relative humidity using air (cathode)/H2(anode)) was obtained, and a remarkable durability of 500,000 accelerated potential cycles was recorded with only a 5% loss of the initial FC potential and 20% loss of the maximum power density, which were far superior properties compared to those of the membrane electrode assembly prepared using carbon black in place of the carbon nanotubes. The present study indicates that the prepared highly durable fuel cell electrocatalyst is a promising material for the next generation of PEMFCs. PMID:26594045

  10. A highly durable fuel cell electrocatalyst based on double-polymer-coated carbon nanotubes.

    PubMed

    Berber, Mohamed R; Hafez, Inas H; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-11-23

    Driven by the demand for the commercialization of fuel cell (FC) technology, we describe the design and fabrication of a highly durable FC electrocatalyst based on double-polymer-coated carbon nanotubes for use in polymer electrolyte membrane fuel cells. The fabricated electrocatalyst is composed of Pt-deposited polybenzimidazole-coated carbon nanotubes, which are further coated with Nafion. By using this electrocatalyst, a high FC performance with a power density of 375 mW/cm(2) (at 70 ˚C, 50% relative humidity using air (cathode)/H2(anode)) was obtained, and a remarkable durability of 500,000 accelerated potential cycles was recorded with only a 5% loss of the initial FC potential and 20% loss of the maximum power density, which were far superior properties compared to those of the membrane electrode assembly prepared using carbon black in place of the carbon nanotubes. The present study indicates that the prepared highly durable fuel cell electrocatalyst is a promising material for the next generation of PEMFCs.

  11. Particle balance study for the fueling efficiency in KSTAR experiments 2013

    NASA Astrophysics Data System (ADS)

    Juhn, J.-. W.; Hahn, S. H.; Hong, S. H.; Song, J. I.; Kim, Y. O.; Kim, K. P.; Kim, J. S.

    2014-10-01

    The efficiencies of the fueling system in the KSTAR have been studied for the 2013 experimental results. The absolute amount of injected fuel or deuterium has been calibrated in advance of the main plasma experiments. This includes the primary actuator of fueling, i.e., gas puffing (GP) with piezoelectric valves located on mid-plane, and supersonic molecular beam injector (SMBI). In addition, neutral beam injectors (NBIs) and their base facility chamber also contribute to the amount of fuel injection whenever they are operated. Low fueling efficiency combined with particle loss due to wall retention essentially results in poor performance of density feedback control magnetic fusion devices such as the KSTAR.

  12. Electrostatic separation of superconducting particles from non-superconducting particles and improvement in fuel atomization by electrorheology

    NASA Astrophysics Data System (ADS)

    Chhabria, Deepika

    This thesis has two major topics: (1) Electrostatic Separation of Superconducting Particles from a Mixture of Non-Superconducting Particles. (2) Improvement in fuel atomization by Electrorheology. (1) Based on the basic science research, the interactions between electric field and superconductors, we have developed a new technology, which can separate superconducting granular particles from their mixture with non-superconducting particles. The electric-field induced formation of superconducting balls is important aspect of the interaction between superconducting particles and electric field. When the applied electric field exceeds a critical value, the induced positive surface energy on the superconducting particles forces them to aggregate into balls or cling to the electrodes. In fabrication of superconducting materials, especially HTSC materials, it is common to come across materials with multiple phases: some grains are in superconducting state while the others are not. Our technology is proven to be very useful in separating superconducting grains from the rest non-superconducting materials. To separate superconducting particles from normal conducting particles, we apply a suitable strong electric field. The superconducting particles cling to the electrodes, while normal conducting particles bounce between the electrodes. The superconducting particles could then be collected from the electrodes. To separate superconducting particles from insulating ones, we apply a moderate electric field to force insulating particles to the electrodes to form short chains while the superconducting particles are collected from the middle of capacitor. The importance of this technology is evidenced by the unsuccessful efforts to utilize the Meissner effect to separate superconducting particles from nonsuperconducting ones. Because the Meissner effect is proportional to the particle volume, it has been found that the Meissner effect is not useful when the superconducting

  13. Characterization of Copper Coatings Deposited by High-Velocity Oxy-Fuel Spray for Thermal and Electrical Conductivity Applications

    NASA Astrophysics Data System (ADS)

    Salimijazi, H. R.; Aghaee, M.; Salehi, M.; Garcia, E.

    2017-08-01

    Copper coatings were deposited on steel substrates by high-velocity oxy-fuel spraying. The microstructure of the feedstock copper powders and free-standing coatings were evaluated by optical and scanning electron microscopy. The x-ray diffraction pattern was utilized to determine phase compositions of powders and coatings. Oxygen content was determined by a LECO-T300 oxygen determiner. The thermal conductivity of the coatings was measured in two directions, through-thickness and in-plane by laser flash apparatus. The electrical resistivity of the coatings was measured by the four-point probe method. Oxygen content of the coatings was two times higher than that of the initial powders (0.35-0.37%). The thermal and electrical conductivities of the coatings were different depending on the direction of the measurement. The thermal and electrical conductivity of the coatings improved after annealing for 6 h at a temperature of 600°C.

  14. SILICON CARBIDE GRAIN BOUNDARY DISTRIBUTIONS, IRRADIATION CONDITIONS, AND SILVER RETENTION IN IRRADIATED AGR-1 TRISO FUEL PARTICLES

    SciTech Connect

    Lillo, T. M.; Rooyen, I. J.; Aguiar, J. A.

    2016-11-01

    Precession electron diffraction in the transmission electron microscope was used to map grain orientation and ultimately determine grain boundary misorientation angle distributions, relative fractions of grain boundary types (random high angle, low angle or coincident site lattice (CSL)-related boundaries) and the distributions of CSL-related grain boundaries in the SiC layer of irradiated TRISO-coated fuel particles. Two particles from the AGR-1 experiment exhibiting high Ag-110m retention (>80%) were compared to a particle exhibiting low Ag-110m retention (<19%). Irradiated particles with high Ag-110m retention exhibited a lower fraction of random, high angle grain boundaries compared to the low Ag-110m retention particle. An inverse relationship between the random, high angle grain boundary fraction and Ag-110m retention is found and is consistent with grain boundary percolation theory. Also, comparison of the grain boundary distributions with previously reported unirradiated grain boundary distributions, based on SEM-based EBSD for similarly fabricated particles, showed only small differences, i.e. a greater low angle grain boundary fraction in unirradiated SiC. It was, thus, concluded that SiC layers with grain boundary distributions susceptible to Ag-110m release were present prior to irradiation. Finally, irradiation parameters were found to have little effect on the association of fission product precipitates with specific grain boundary types.

  15. [Alpha-chymotrypsin immobilized on ferromagnetic particles coated with titanium oxide: production and catalytic properties].

    PubMed

    Izmaĭlov, A F; Kiselev, M V; Vakurov, A V; Gladilin, A K; Levashov, A V

    2000-01-01

    Immobilization of alpha-chymotrypsin on magnetic particles with stable coat with titanium oxides as a main constituent allowed the biocatalytic system to be quickly and qualitatively separated into the components after completion of the enzymatic reaction. X-ray phase analysis demonstrated that the coat of magnetic particles is composed mainly of titanium dioxide in brookite modification. The maximal capacity of the particles amounted to 0.3 mg protein/mg particles. It was demonstrated that the reaction catalyzed by immobilized alpha-chymotrypsin proceeds in a kinetic mechanism due to a high dispersion of the ferromagnetic particles. The catalytic constant (25 s-1) and KM (0.17 mM) for the immobilized enzyme for the hydrolysis of N-acetyl-L-tyrosine ethyl ester are comparable to the corresponding characteristics for the free enzyme.

  16. Fracture of a Brittle-Particle Ductile Matrix Composite with Applications to a Coating System

    NASA Astrophysics Data System (ADS)

    Bianculli, Steven J.

    In material systems consisting of hard second phase particles in a ductile matrix, failure initiating from cracking of the second phase particles is an important failure mechanism. This dissertation applies the principles of fracture mechanics to consider this problem, first from the standpoint of fracture of the particles, and then the onset of crack propagation from fractured particles. This research was inspired by the observation of the failure mechanism of a commercial zinc-based anti-corrosion coating and the analysis was initially approached as coatings problem. As the work progressed it became evident that failure mechanism was relevant to a broad range of composite material systems and research approach was generalized to consider failure of a system consisting of ellipsoidal second phase particles in a ductile matrix. The starting point for the analysis is the classical Eshelby Problem, which considered stress transfer from the matrix to an ellipsoidal inclusion. The particle fracture problem is approached by considering cracks within particles and how they are affected by the particle/matrix interface, the difference in properties between the particle and matrix, and by particle shape. These effects are mapped out for a wide range of material combinations. The trends developed show that, although the particle fracture problem is very complex, the potential for fracture among a range of particle shapes can, for certain ranges in particle shape, be considered easily on the basis of the Eshelby Stress alone. Additionally, the evaluation of cracks near the curved particle/matrix interface adds to the existing body of work of cracks approaching bi-material interfaces in layered material systems. The onset of crack propagation from fractured particles is then considered as a function of particle shape and mismatch in material properties between the particle and matrix. This behavior is mapped out for a wide range of material combinations. The final section of

  17. Improving flow properties of ibuprofen by fluidized bed particle thin-coating.

    PubMed

    Ehlers, Henrik; Räikkönen, Heikki; Antikainen, Osmo; Heinämäki, Jyrki; Yliruusi, Jouko

    2009-02-23

    The surfaces of ibuprofen particles (d(50) 42 microm) were modified by coating the particles with diluted aqueous hydroxypropyl methylcellulose (HPMC) solution in an instrumentated top-spray fluid bed granulator. The objective was to evaluate whether an extremely thin polymer coating could be an alternative to granulation in enhancing powder flow and processing properties. The studied variables were inlet air temperature and spray rate. The treated powders showed a clear improvement in flow rate as measured with a flow meter designed for powders with poor flow properties. The particle size was determined using optical microscopy and image analysis. The particle size, size distribution and circularity of the treated and untreated ibuprofen batches showed no difference from each other. Consequently, the improvement in flow properties can be attributed to the trace amounts of hydroxypropyl methylcellulose applied onto the particle surfaces. In conclusion, fluidized bed particle thin-coating (PTC) alters the surface of ibuprofen powder particles and improves the flow properties of ibuprofen powder with changes in neither particle size, size distribution nor morphology.

  18. Deposition of Coatings from Live Yeast Cells and Large Particles by “Convective-Sedimentation” Assembly

    PubMed Central

    Jerrim, Lindsey B.; Velev, Orlin D.

    2009-01-01

    Convective assembly at high volume fraction was used for the rapid deposition of uniform, close-packed coatings of Saccharomyces cerevisiae yeast cells onto glass slides. A computational model was developed to calculate the thickness profiles of such coatings for different set of conditions. Both the experiments and the numerical simulations demonstrated that the deposition process is strongly affected by the presence of sedimentation. The deposition device was inclined to increase the uniformity of the coatings by causing the cells to sediment toward the three-phase contact line. In accordance with the simulation, the experiments showed that both increasing the angle of the device and decreasing the angle between the slides increased the uniformity of the deposited coatings. Finally, the “convective-sedimentation” assembly method was used to deposit mixed layers of live cells and large latex particles as an example of immobilized biologically active composite coatings. PMID:19366200

  19. Influence of carbonyl iron particle coating with silica on the properties of magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Małecki, P.; Królewicz, M.; Hiptmair, F.; Krzak, J.; Kaleta, J.; Major, Z.; Pigłowski, J.

    2016-10-01

    In this paper, the influence of encapsulating carbonyl iron particles with various silica coatings on the properties of magnetorheological elastomers (MREs) was investigated. A soft styrene-ethylene-butylene-styrene thermoplastic elastomer was used as the composite’s polymer matrix. Spherical carbonyl iron powder (CIP) acted as the ferromagnetic filler. In order to improve the metal-polymer interaction, carbonyl iron particles were coated with two types of single and six types of double silica layers. The first layer was created through a TMOS or TEOS hydrolysis whereas the second one was composed of organosilanes. The mechanical properties of MREs containing 38.5 vol% of CIP were analysed under dynamic loading conditions. To investigate the magnetorheological effect in these composites, a 430 mT magnetic field, generated by an array of permanent magnets, was applied during testing. The results revealed that the magnetomechanical response of the MREs differs substantially, depending on the kind of particle coating.

  20. Electrodeposition, characterization, and antibacterial activity of zinc/silver particle composite coatings

    NASA Astrophysics Data System (ADS)

    Reyes-Vidal, Y.; Suarez-Rojas, R.; Ruiz, C.; Torres, J.; Ţălu, Ştefan; Méndez, Alia; Trejo, G.

    2015-07-01

    Composite coatings consisting of zinc and silver particles (Zn/AgPs) with antibacterial activity were prepared using an electrodeposition technique. The morphology, composition, and structure of the Zn/AgPs composite coatings were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), inductively coupled plasma (ICP) spectrometry, and X-ray diffraction (XRD). The antibacterial properties of the coatings against the microorganisms Escherichia coli as a model Gram-negative bacterium and Staphylococcus aureus as a model Gram-positive bacterium were studied quantitatively and qualitatively. The results revealed that the dispersant cetyltrimethylammonium bromide (CTAB) assisted in the formation of a stable suspension of Ag particles in the electrolytic bath for 24 h. Likewise, a high concentration of CTAB in the electrolytic bath promoted an increase in the number of Ag particles occluded in the Zn/AgPs coatings. The Zn/AgPs coatings that were obtained were compact, smooth, and shiny materials. Antimicrobial tests performed on the Zn/AgPs coatings revealed that the inhibition of bacterial growth after 30 min of contact time was between 91% and 98% when the AgPs content ranged from 4.3 to 14.0 mg cm-3.

  1. Controlling the radiative properties of cool black-color coatings pigmented with CuO submicron particles

    NASA Astrophysics Data System (ADS)

    Gonome, Hiroki; Baneshi, Mehdi; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-01-01

    The objective of this study was to design a pigmented coating with dark appearance that maintains a low temperature while exposed to sunlight. The radiative properties of a black-color coating pigmented with copper oxide (CuO) submicron particles are described. In the present work, the spectral behavior of the CuO-pigmented coating was calculated. The radiative properties of CuO particles were evaluated, and the radiative transfer in the pigmented coating was modeled using the radiation element method by ray emission model (REM2). The coating is made using optimized particles. The reflectivity is measured by spectroscopy and an integrating sphere in the visible (VIS) and near infrared (NIR) regions. By using CuO particles controlled in size, we were able to design a black-color coating with high reflectance in the NIR region. The coating substrate also plays an important role in controlling the reflectance. The NIR reflectance of the coating on a standard white substrate with appropriate coating thickness and volume fraction was much higher than that on a standard black substrate. From the comparison between the experimental and calculated results, we know that more accurate particle size control enables us to achieve better performance. The use of appropriate particles with optimum size, coating thickness and volume fraction on a suitable substrate enables cool and black-color coating against solar irradiation.

  2. Analysis of Venezuelan equine encephalitis replicon particles packaged in different coats.

    PubMed

    Kamrud, Kurt I; Alterson, Kim D; Andrews, Chasity; Copp, Laura O; Lewis, Whitney C; Hubby, Bolyn; Patel, Deepa; Rayner, Jonathan O; Talarico, Todd; Smith, Jonathan F

    2008-07-16

    The Venezuelan equine encephalitis (VEE) virus replicon system was used to produce virus-like replicon particles (VRP) packaged with a number of different VEE-derived glycoprotein (GP) coats. The GP coat is believed to be responsible for the cellular tropism noted for VRP and it is possible that different VEE GP coats may have different affinities for cells. We examined VRP packaged in four different VEE GP coats for their ability to infect cells in vitro and to induce both humoral and cellular immune responses in vivo. The VRP preparations were characterized to determine both infectious units (IU) and genome equivalents (GE) prior to in vivo analysis. VRP packaged with different VEE GP coats demonstrated widely varying GE/IU ratios based on Vero cell infectivity. BALB/c mice were immunized with the different VRP based on equal GE titers and the humoral and cellular responses to the expressed HIV gag gene measured. The magnitude of the immune responses measured in mice revealed small but significant differences between different GP coats when immunization was based on GE titers. We suggest that care should be taken when alternative coat proteins are used to package vector-based systems as the titers determined by cell culture infection may not represent accurate particle numbers and in turn may not accurately represent actual in vivo dose.

  3. Recovery and recycling of uranium from rejected coated particles for compact high temperature reactors

    NASA Astrophysics Data System (ADS)

    Pai, Rajesh V.; Mollick, P. K.; Kumar, Ashok; Banerjee, J.; Radhakrishna, J.; Chakravartty, J. K.

    2016-05-01

    UO2 microspheres prepared by internal gelation technique were coated with pyrolytic carbon and silicon carbide using CVD technique. The particles which were not meeting the specifications were rejected. The rejected/failed UO2 based coated particles prepared by CVD technique was used for oxidation and recovery and recycling. The oxidation behaviour of sintered UO2 microspheres coated with different layers of carbon and SiC was studied by thermal techniques to develop a method for recycling and recovery of uranium from the failed/rejected coated particles. It was observed that the complete removal of outer carbon from the spheres is difficult. The crushing of microspheres enabled easier accessibility of oxygen and oxidation of carbon and uranium at 800-1000 °C. With the optimized process of multiple crushing using die & plunger and sieving the broken coated layers, we could recycle around fifty percent of the UO2 microspheres which could be directly recoated. The rest of the particles were recycled using a wet recycling method.

  4. Preparation of antibacterial composite material of natural rubber particles coated with silica and titania

    NASA Astrophysics Data System (ADS)

    Wisutiratanamanee, Apisit; Poompradub, Sirilux; Poochinda, Kunakorn

    2014-06-01

    Silica coating, followed by titania coating, was performed over spray-dried natural rubber (NR) compound for physical and anti-bacterial characterizations. Titania has a strong photo-oxidative catalytic property, which can disinfect bacteria, but may degrade NR. Therefore, silica coating was intended to form a barrier between NR and titania. First, NR particles were prepared by spray-drying of NR compound latex, formulated for household glove products, mixed with sodium dodecyl sulfate (SDS) to reduce particle agglomeration. The factorial experimental design was employed to investigate the effects of nozzle flow rate (500-700 Lh-1), inlet air temperature (110-150 °C), SDS content (35-55 phr) and mass flow rate (1.2-1.7 g rubber/min) on NR yield and moisture content. Then, the NR compound particles prepared at the optimum condition were coated with silica, using tetraethoxysilane (TEOS) as the precursor, by chemical vapor deposition (CVD) at 60 °C for 2-48 hours. Next, the particles were coated with titania using titanium tetrafluoride (TiF4) by liquid phase deposition (LPD) at 60 ºC for 4-8 hours. The NR composites were characterized for surface morphology by SEM, silica and titania content by TGA and EDX. The NR composites were found to cause more than 99% reduction of Escherichia coli and Staphylococcus aureus under 1-hour exposure to natural light.

  5. Influence on the wear resistance of the particle size used in coatings of Alumina

    NASA Astrophysics Data System (ADS)

    Santos, A.; Guzmán, R.; Ramirez, Z. Y.

    2017-01-01

    In the literature, it is common to find that the size of the particles used in coatings through thermal spraying processes influences the hardness and wear resistance thereof; this project aimed to quantify the importance of this parameter in the adhesive and abrasive wear resistance when aluminium oxide is deposited on a substrate of AISI 1020 steel, through a thermal spraying by flame process. The methodology consisted of: a) morphological characterization of the powder used in the coatings by scanning electron microscopy, b) deposition of coatings, c) testing of adhesive and abrasive wear (ASTM G99-05 Standard test method for wear testing with a pin-on-disk apparatus and ASTM G65-04 Standard test method for measuring abrasion using dry sand/rubber wheel apparatus), and d) statistical analysis to determine the influence of particle size on wear resistance. The average size of the powder used for coatings was 92, 1690, 8990 and 76790nm. The obtained results allow to identify an inversely proportional behaviour between particle size and wear resistance, in both types of wear (adhesive and abrasive) is shown a logarithmic trend indicating an increase in loss mass during the test as the particle size is also increased and therefore a decrease in wear resistance of the coating.

  6. Fuel Structure and Pressure Effects on the Formation of Soot Particles in Diffusion Flames

    DTIC Science & Technology

    1990-05-01

    higher values of the pressure power dependence appear to be related to fuel structure effects , the direct nature of which remains to be understood...61102F 2308 A2 11. TITLE (Include Security Classification) "Fuel Structure and Pressure Effects on the Formation of Soot Particlesin Diffusion Flames...block number) Studies emphasizing the effects of fuel concentration and operating pressure on the formation of soot particles have been conducted in a

  7. Tracking Protein-coated Particles in 3D.

    NASA Astrophysics Data System (ADS)

    Gratton, Enrico

    2006-03-01

    The utilization of 2-photon microscopy in the field of Cell Biology is of increasing importance because it allows imaging of living cells, including those systems where UV imaging is not possible due to photobleaching or photodamage limitations. We propose a novel approach using 2-photon excitation based on the use of a scanner to produce an effective ``intensity trap''. As the particle moves in this trap (note that there is no force applied on the particle at the power level we are using for particle detection), the detection system continuously calculates the position of the particle in the trap. As the position of the particle is calculated with respect to the trap, the scanner position is moved to minimize the ``modulation'' of the light intensity in the trap. In practice, we set the scanner to perform an orbit around the particle in about 1 millisecond. The sampling rate is chosen such that many points (32 or 64) are acquired during the orbit. An FFT (Fast Fourier Transform) is performed on the points acquired during one orbit or after a series of orbits. The DC, AC and phase of the first harmonic of the FFT are calculated. The value of the modulation varies monotonically as the distance of the particle from the center of the orbit is increased so that for every value of the modulation we can estimate the value of the distance of the particle from the center of the orbit. The phase of the first harmonic gives the angular position of the particle with respect to the scanner zero phase which is known relative to the lab coordinates. The effective bandwidth of the tracking system depends on the maximum frequency for sinusoidal oscillation of the scanner, which is about 5 kHz for our galvano-scanner and on the number of photons needed for detecting the particle against the noise. Of course, there are other important considerations. First, if the motion of the particle is too fast such that after one orbit the particle moves too far from the new position calculated

  8. TRISO-Coated Fuel Processing to Support High Temperature Gas-Cooled Reactors

    SciTech Connect

    Del Cul, G.D.

    2002-10-01

    The initial objective of the work described herein was to identify potential methods and technologies needed to disassemble and dissolve graphite-encapsulated, ceramic-coated gas-cooled-reactor spent fuels so that the oxide fuel components can be separated by means of chemical processing. The purpose of this processing is to recover (1) unburned fuel for recycle, (2) long-lived actinides and fission products for transmutation, and (3) other fission products for disposal in acceptable waste forms. Follow-on objectives were to identify and select the most promising candidate flow sheets for experimental evaluation and demonstration and to address the needs to reduce technical risks of the selected technologies. High-temperature gas-cooled reactors (HTGRs) may be deployed in the next -20 years to (1) enable the use of highly efficient gas turbines for producing electricity and (2) provide high-temperature process heat for use in chemical processes, such as the production of hydrogen for use as clean-burning transportation fuel. Also, HTGR fuels are capable of significantly higher burn-up than light-water-reactor (LWR) fuels or fast-reactor (FR) fuels; thus, the HTGR fuels can be used efficiently for transmutation of fissile materials and long-lived actinides and fission products, thereby reducing the inventory of such hazardous and proliferation-prone materials. The ''deep-burn'' concept, described in this report, is an example of this capability. Processing of spent graphite-encapsulated, ceramic-coated fuels presents challenges different from those of processing spent LWR fuels. LWR fuels are processed commercially in Europe and Japan; however, similar infrastructure is not available for processing of the HTGR fuels. Laboratory studies on the processing of HTGR fuels were performed in the United States in the 1960s and 1970s, but no engineering-scale processes were demonstrated. Currently, new regulations concerning emissions will impact the technologies used in

  9. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  10. Reactor physics behavior of transuranic-bearing TRISO-particle fuel in a pressurized water reactor

    SciTech Connect

    Pope, M. A.; Sen, R. S.; Ougouag, A. M.; Youinou, G.; Boer, B.

    2012-07-01

    Calculations have been performed to assess the neutronic behavior of pins of Fully-Ceramic Micro-encapsulated (FCM) fuel in otherwise-conventional Pressurized Water Reactor (PWR) fuel pins. The FCM fuel contains transuranic (TRU) - only oxide fuel in tri-isotropic (TRISO) particles with the TRU loading coming from the spent fuel of a conventional LWR after 5 years of cooling. Use of the TRISO particle fuel would provide an additional barrier to fission product release in the event of cladding failure. Depletion calculations were performed to evaluate reactivity-limited burnup of the TRU-only FCM fuel. These calculations showed that due to relatively little space available for fuel, the achievable burnup with these pins alone is quite small. Various reactivity parameters were also evaluated at each burnup step including moderator temperature coefficient (MTC), Doppler, and soluble boron worth. These were compared to reference UO{sub 2} and MOX unit cells. The TRU-only FCM fuel exhibits degraded MTC and Doppler coefficients relative to UO{sub 2} and MOX. Also, the reactivity effects of coolant voiding suggest that the behavior of this fuel would be similar to a MOX fuel of very high plutonium fraction, which are known to have positive void reactivity. In general, loading of TRU-only FCM fuel into an assembly without significant quantities of uranium presents challenges to the reactor design. However, if such FCM fuel pins are included in a heterogeneous assembly alongside LEU fuel pins, the overall reactivity behavior would be dominated by the uranium pins while attractive TRU destruction performance levels in the TRU-only FCM fuel pins is retained. From this work, it is concluded that use of heterogeneous assemblies such as these appears feasible from a preliminary reactor physics standpoint. (authors)

  11. Reactor Physics Behavior of Transuranic-Bearing TRISO-Particle Fuel in a Pressurized Water Reactor

    SciTech Connect

    Michael A. Pope; R. Sonat Sen; Abderrafi M. Ougouag; Gilles Youinou; Brian Boer

    2012-04-01

    Calculations have been performed to assess the neutronic behavior of pins of Fully-Ceramic Micro-encapsulated (FCM) fuel in otherwise-conventional Pressurized Water Reactor (PWR) fuel pins. The FCM fuel contains transuranic (TRU)-only oxide fuel in tri-isotropic (TRISO) particles with the TRU loading coming from the spent fuel of a conventional LWR after 5 years of cooling. Use of the TRISO particle fuel would provide an additional barrier to fission product release in the event of cladding failure. Depletion calculations were performed to evaluate reactivity-limited burnup of the TRU-only FCM fuel. These calculations showed that due to relatively little space available for fuel, the achievable burnup with these pins alone is quite small. Various reactivity parameters were also evaluated at each burnup step including moderator temperature coefficient (MTC), Doppler, and soluble boron worth. These were compared to reference UO{sub 2} and MOX unit cells. The TRU-only FCM fuel exhibits degraded MTC and Doppler coefficients relative to UO{sub 2} and MOX. Also, the reactivity effects of coolant voiding suggest that the behavior of this fuel would be similar to a MOX fuel of very high plutonium fraction, which are known to have positive void reactivity. In general, loading of TRU-only FCM fuel into an assembly without significant quantities of uranium presents challenges to the reactor design. However, if such FCM fuel pins are included in a heterogeneous assembly alongside LEU fuel pins, the overall reactivity behavior would be dominated by the uranium pins while attractive TRU destruction performance levels in the TRU-only FCM fuel pins is. From this work, it is concluded that use of heterogeneous assemblies such as these appears feasible from a preliminary reactor physics standpoint.

  12. [Behavior of fuel hot particles in the body of cows at oral intake].

    PubMed

    Kashparov, V A; Lazarev, N M; Ioshchenko, V I

    1997-01-01

    It was studied the behaviour of fuel hot particles (analogous to Chernobyl) in gastrointestinal tract of cows. The values of caesium and strontium radionuclides transfer to the cows organism and its transition parameters to milk after the single per oral intake to the organism of animals are estimated. It is shown, that the biological simplicity of radionuclides in the fuel hot particles at two parameters lower, than the same radionuclides in washed phases.

  13. STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment

    NASA Astrophysics Data System (ADS)

    Leng, B.; van Rooyen, I. J.; Wu, Y. Q.; Szlufarska, I.; Sridharan, K.

    2016-07-01

    Historic and recent post-irradiation-examination from the German AVR and Advanced Gas Reactor Fuel Development and Qualification Project have shown that 110 m Ag is released from intact tristructural isotropic (TRISO) fuel. Although TRISO fuel particle research has been performed over the last few decades, little is known about how metallic fission products are transported through the SiC layer, and it was not until March 2013 that Ag was first identified in the SiC layer of a neutron-irradiated TRISO fuel particle. The existence of Pd- and Ag-rich grain boundary precipitates, triple junction precipitates, and Pd nano-sized intragranular precipitates in neutron-irradiated TRISO particle coatings was investigated using Scanning Transmission Electron Microscopy and Energy Dispersive Spectroscopy analysis to obtain more information on the chemical composition of the fission product precipitates. A U-rich fission product honeycomb shape precipitate network was found near a micron-sized precipitate in a SiC grain about ∼5 μm from the SiC-inner pyrolytic carbon interlayer, indicating a possible intragranular transport path for uranium. A single Ag-Pd nano-sized precipitate was found inside a SiC grain, and this is the first research showing such finding in irradiated SiC. This finding may possibly suggest a possible Pd-assisted intragranular transport mechanism for Ag and may be related to void or dislocation networks inside SiC grains. Preliminary semi-quantitative analysis indicated the micron-sized precipitates to be Pd2Si2U with carbon existing inside these precipitates. However, the results of such analysis for nano-sized precipitates may be influenced by the SiC matrix. The results reported in this paper confirm the co-existence of Cd with Ag in triple points reported previously.

  14. Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation.

    PubMed

    Jung, Heejung; Kittelson, David B; Zachariah, Michael R

    2006-08-15

    Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.

  15. Particle induced gamma and X-ray emission spectroscopies of lithium based alloy coatings

    NASA Astrophysics Data System (ADS)

    Laird, Jamie S.; Hughes, Anthony E.; Ryan, Chris G.; Visser, P.; Terryn, H.; Mol, J. M. C.

    2017-08-01

    Lithium based inhibitors in aerospace coatings are seen as excellent replacements for their chromium counterparts which are both carcinogenic and heavier. However, Li is generally difficult to detect and following changes in its distribution due to corrosion is impossible with many standard techniques. Combining MeV Particle Induced Gamma and X-ray emission provides a powerful tool and in this paper we summarise some recent experiments on such coatings using the CSIRO Nuclear Microprobe. PIGE mapping of the LiCO3 particles and their patterning illustrates how the method will be extremely useful in monitoring surface corrosion.

  16. Anticorrosion properties of tin oxide coatings for carbonaceous bipolar plates of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Kinumoto, Taro; Nagano, Keita; Yamamoto, Yuji; Tsumura, Tomoki; Toyoda, Masahiro

    2014-03-01

    An anticorrosive surface treatment of a carbonaceous bipolar plate used in proton exchange membrane fuel cells (PEMFCs) was demonstrated by addition of a tin oxide surface coating by liquid phase deposition (LPD), and its effectiveness toward corrosion prevention was determined. The tin oxide coating was deposited by immersion in tin fluoride and boric acid solutions, without any observable decrease in the bipolar plate electrical conductivity. Anticorrosion properties of a flat carbonaceous bipolar plate were investigated in an aqueous HClO4 electrolyte solution (10 μmol dm-3) at 80 °C. CO2 release due to corrosion was significant for the bare specimen above 1.3 V, whereas no CO2 release was noted for the tin-oxide-coated specimen, even approaching 1.5 V. Moreover, minimal changes in contact angle against a water droplet before and after treatment indicated suppressed corrosion of the surface-coated specimen. Anticorrosion properties were also confirmed for a model bipolar plate having four gas flow channels. The tin oxide layer remained on the channel surfaces (inner walls, corners and intersections) after durability tests. Based on these results, tin-oxide-based surface coatings fabricated by LPD show promise as an anticorrosion technique for carbonaceous bipolar plates for PEMFCs.

  17. Multilayer (TiN, TiAlN) ceramic coatings for nuclear fuel cladding

    NASA Astrophysics Data System (ADS)

    Alat, Ece; Motta, Arthur T.; Comstock, Robert J.; Partezana, Jonna M.; Wolfe, Douglas E.

    2016-09-01

    In an attempt to develop an accident-tolerant fuel (ATF) that can delay the deleterious consequences of loss-of-coolant-accidents (LOCA), multilayer coatings were deposited onto ZIRLO® coupon substrates by cathodic arc physical vapor deposition (CA-PVD). Coatings were composed of alternating TiN (top) and Ti1-xAlxN (2-layer, 4-layer, 8-layer and 16-layer) layers. The minimum TiN top coating thickness and coating architecture were optimized for good corrosion and oxidation resistance. Corrosion tests were performed in static pure water at 360 °C and 18.7 MPa for up to 90 days. The optimized coatings showed no spallation/delamination and had a maximum of 6 mg/dm2 weight gain, which is 6 times smaller than that of a control sample of uncoated ZIRLO® which showed a weight gain of 40.2 mg/dm2. The optimized architecture features a ∼1 μm TiN top layer to prevent boehmite phase formation during corrosion and a TiN/TiAlN 8-layer architecture which provides the best corrosion performance.

  18. Test plan for techniques to measure and remove coatings from K West Basin fuel elements

    SciTech Connect

    Bridges, A.E.

    1998-06-17

    Several types of coatings have previously been visually identified on the surface of 105-K East and 105-K West Basins fuel elements. One type of coating (found only in K West Basin) in particular was found to be a thick translucent material that was often seen to be dislodged from the elements as flakes when the elements were handled during visual examinations (Pitner 1997). Subsequently it was determined (for one element only in a hot cell) that this material, in the dry condition, could easily be removed from the element using a scraping tool. The coating was identified as Al(OH){sub 3} through X-ray diffraction (XRD) analyses and to be approximately 60 {micro}m thick via scanning electron microscopy (SEM). However, brushing under water in the basin using numerous mechanical strokes failed to satisfactorily remove these coatings in their thickest form as judged by appearance. Such brushing was done with only one type of metal brush, a brush design previously found satisfactory for removing UO{sub 4}.xH{sub 2}O coatings from the elements.

  19. Abrasive wear of high velocity oxygen fuel (HVOF) superalloy coatings under vibration load

    NASA Astrophysics Data System (ADS)

    Kandeva, M.; Ivanova, B.; Karastoyanov, D.; Grozdanova, T.; Assenova, E.

    2017-02-01

    The present paper considers wear of coatings deposited by HVOF (High velocity oxy-fuel) technology, under conditions of dry friction against abrasive surface accompanied with the action of vibrations perpendicular to the sliding axis. Results are obtained with four type coatings: two types with Ni matrix of composition 602P – without preliminary heating of the basic surface (the substrate) and after substrate heating up to 650°C in a chamber; coating WC-12Co with tungsten matrix and coating obtained by 1:1 proportion powder mixture of both compositions 602P and WC-12Co. Results about the thickness, hardness and coating’ morphology are presented, as well as dependences of the wear and the relative wear resistance on vibration speeds in the interval 3.03 to 21.08 mm/s. New results are obtained about the nonlinear relationship between abrasive wear and vibration speed showing minimal wear for all specimens by 6.04 mm/s. It is found that lowest wear shows WC-12Co coating in the entire interval of vibration speed variation: 3.03 to 21.08 mm/s. The obtained results are new in the literature; they are not presented and published by the authors.

  20. Microstructure of TRISO Coated Particles from the AGR-1 Experiment I: SiC Grain Size and Grain Boundary Character

    SciTech Connect

    Rita Kirchhofer; John D, Hunn; Paul A. Demkowicz; James I. Cole; Brian P. Gorman

    2013-01-01

    Pre-irradiation SiC microstructures in TRISO coated fuel particles from the AGR-1 experiment were quantitatively characterized using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). From EBSD it was determined that only the cubic polymorph of as-deposited SiC was present and the SiC had a high fraction of CSL S3 grain boundaries. Additionally, the local area misorientation (LAM), which is a qualitative measurement of strain in the SiC lattice, was mapped for each fuel variant. The morphology of the SiC / IPyC interfaces were characterized by TEM following site-specific focused ion beam (FIB) specimen preparation. It was determined that the SiC layer had a heavily faulted microstructure typical of CVD deposited SiC and that the average grain diameter increased from the SiC/IPyC interface for all the fuel variants, except V3 that showed a constant grain size across the layer.

  1. Modeled heating and surface erosion comparing motile (gas borne) and stationary (surface coating) inert particle additives

    SciTech Connect

    Buckingham, A.C.; Siekhaus, W.J.

    1982-09-27

    The unsteady, non-similar, chemically reactive, turbulent boundary layer equations are modified for gas plus dispersed solid particle mixtures, for gas phase turbulent combustion reactions and for heterogeneous gas-solid surface erosive reactions. The exterior (ballistic core) edge boundary conditions for the solutions are modified to include dispersed particle influences on core propellant combustion-generated turbulence levels, combustion reactants and products, and reaction-induced, non-isentropic mixture states. The wall surface (in this study it is always steel) is considered either bare or coated with a fixed particle coating which is conceptually non-reactive, insulative, and non-ablative. Two families of solutions are compared. These correspond to: (1) consideration of gas-borne, free-slip, almost spontaneously mobile (motile) solid particle additives which influence the turbulent heat transfer at the uncoated steel surface and, in contrast, (2) consideration of particle-free, gas phase turbulent heat transfer to the insulated surface coated by stationary particles. Significant differences in erosive heat transfer are found in comparing the two families of solutions over a substantial range of interior ballistic flow conditions. The most effective influences on reducing erosive heat transfer appear to favor mobile, gas-borne particle additives.

  2. Preparation of agglomeration-free hematite particles coated with silica and their reduction behavior in hydrogen.

    PubMed

    Iijima, Motoyuki; Yonemochi, Yuichi; Kimata, Mitsumasa; Hasegawa, Masahiro; Tsukada, Mayumi; Kamiya, Hidehiro

    2005-07-15

    To prepare silica-coated hematite particles without agglomeration, the effects of solid fraction, ion content in solution, and designed layer thickness on agglomeration and dispersion behavior after silica coating were examined. Since the ion concentration remained high in suspension after the hematite particles were prepared, these particles formed aggregates by the compression of an electric double layer on the hematite and silica layer produced a solid bridge between primary hematite particles. Silica bridge formation and agglomeration were almost completely prevented by decreasing the ion concentration and solid fraction of the hematite particles. Furthermore, the effects of the silica-layer thickness and structure on the reduction of hematite to iron under hydrogen gas flow and the iron core stability under air were discussed. When the solid fraction was low in suspension to prevent agglomeration during coating, a densely packed structure of nanoparticles formed by heterogeneous nucleation was observed on the silica-layer surface. Since this structure could not completely prevent oxide diffusion, the layer thickness was increased to 40 nm to obtain a stable iron core under air. Although a dense uniform layer was produced at a high solid fraction during coating, its thickness was reduced to 20 nm to completely reduce hematite to iron.

  3. Tribo-Mechanical Properties of HVOF Deposited Fe3Al Coatings Reinforced with TiB2 Particles for Wear-Resistant Applications

    PubMed Central

    Amiriyan, Mahdi; Blais, Carl; Savoie, Sylvio; Schulz, Robert; Gariépy, Mario; Alamdari, Houshang

    2016-01-01

    This study reveals the effect of TiB2 particles on the mechanical and tribological properties of Fe3Al-TiB2 composite coatings against an alumina counterpart. The feedstock was produced by milling Fe3Al and TiB2 powders in a high energy ball mill. The high-velocity oxy-fuel (HVOF) technique was used to deposit the feedstock powder on a steel substrate. The effect of TiB2 addition on mechanical properties and dry sliding wear rates of the coatings at sliding speeds ranging from 0.04 to 0.8 m·s−1 and loads of 3, 5 and 7 N was studied. Coatings made from unreinforced Fe3Al exhibited a relatively high wear rate. The Vickers hardness, elastic modulus and wear resistance of the coatings increased with increasing TiB2 content in the Fe3Al matrix. The wear mechanisms strongly depended on the sliding speed and the presence of TiB2 particles but were less dependent on the applied load. This study reveals the effect of TiB2 particles on the mechanical and tribological properties of Fe3Al-TiB2 composite coatings against an alumina counterpart. The feedstock was produced by milling Fe3Al and TiB2 powders in a high energy ball mill. The high-velocity oxy-fuel (HVOF) technique was used to deposit the feedstock powder on a steel substrate. The effect of TiB2 addition on mechanical properties and dry sliding wear rates of the coatings at sliding speeds ranging from 0.04 to 0.8 m·s−1 and loads of 3, 5 and 7 N was studied. Coatings made from unreinforced Fe3Al exhibited a relatively high wear rate. The Vickers hardness, elastic modulus and wear resistance of the coatings increased with increasing TiB2 content in the Fe3Al matrix. The wear mechanisms strongly depended on the sliding speed and the presence of TiB2 particles but were less dependent on the applied load. This study reveals the effect of TiB2 particles on the mechanical and tribological properties of Fe3Al-TiB2 composite coatings against an alumina counterpart. The feedstock was produced by milling Fe3Al and TiB2

  4. Method for testing the strength and structural integrity of nuclear fuel particles

    DOEpatents

    Lessing, P.A.

    1995-10-17

    An accurate method for testing the strength of nuclear fuel particles is disclosed. Each particle includes an upper and lower portion, and is placed within a testing apparatus having upper and lower compression members. The upper compression member includes a depression therein which is circular and sized to receive only part of the upper portion of the particle. The lower compression member also includes a similar depression. The compression members are parallel to each other with the depressions therein being axially aligned. The fuel particle is then placed between the compression members and engaged within the depressions. The particle is then compressed between the compression members until it fractures. The amount of force needed to fracture the particle is thereafter recorded. This technique allows a broader distribution of forces and provides more accurate results compared with systems which distribute forces at singular points on the particle. 13 figs.

  5. Method for testing the strength and structural integrity of nuclear fuel particles

    DOEpatents

    Lessing, Paul A.

    1995-01-01

    An accurate method for testing the strength of nuclear fuel particles. Each particle includes an upper and lower portion, and is placed within a testing apparatus having upper and lower compression members. The upper compression member includes a depression therein which is circular and sized to receive only part of the upper portion of the particle. The lower compression member also includes a similar depression. The compression members are parallel to each other with the depressions therein being axially aligned. The fuel particle is then placed between the compression members and engaged within the depressions. The particle is then compressed between the compression members until it fractures. The amount of force needed to fracture the particle is thereafter recorded. This technique allows a broader distribution of forces and provides more accurate results compared with systems which distribute forces at singular points on the particle.

  6. Characterization of Organic Coatings on Hygroscopic Salt Particles and their Atmospheric Impacts

    SciTech Connect

    Zelenyuk, Alla; Ezell, Michael J.; Perraud, Veronique; Johnson, Stanley N.; Bruns, Emily; Yu, Yong; Imre, D.; Alexander, M. L.; Finlayson-Pitts, Barbara J.

    2010-03-30

    The photooxidation of α-pinene in the presence of NO2, with and without added NaNO3 seed particles, has been studied in a large diameter flow tube. Particles formed by homogeneous nucleation and by condensation on the pre-existing seeds were sampled at various stages of the reaction, dried using four diffusion dryers, size selected at different mobility diameters (dm) using a differential mobility analyzer (DMA), and characterized with a single particle mass spectrometer (SPLAT II). It was found that homogeneously nucleated particles are spherical, have a density (ρ) of 1.25 ± 0.02 g cm-3 (± 2 σ) and contain a significant amount of organic nitrates. The mass spectra of the low volatility products condensed on the NaNO3 seed particles were found to be virtually the same as in the case of homogeneous nucleation. The data show that the presence of even a submonolayer of organics on the NaNO3 particles causes water retention that leads to a decrease in particle density and that the amount of water retained increases with organic coating thickness. Thicker coatings appear to inhibit water evaporation from the particle seeds altogether. This suggests that in the atmosphere, where low volatility organics are plentiful, some hygroscopic salts will retain water and have different densities and refractive indices than expected in the absence of the organic coating. This water retention combined with the organic shell on the particles can potentially impact light scattering by these particles and activity as cloud condensation nuclei (CCN), as well as heterogeneous chemistry and photochemistry on the particles.

  7. Development of metal-coated ceramic anodes for molten carbonate fuel cells. Final report

    SciTech Connect

    Khandkar, A.C.; Elangovan, S.; Marianowski, L.G.

    1990-03-01

    This report documents the developmental efforts on metal coating of various ceramic substrates (LiAlO{sub 2}, SrTiO{sub 3}, and LiFeO{sub 2}) and the critical issues associated with fabricating anodes using metal-coated LiAlO{sub 2} substrates. Electroless Ni and Cu coating technology was developed to achieve complete metal coverage on LiAlO{sub 2} powder substrates. Metal coated SrTiO{sub 3} powders were fabricated into anodes by a process identical to that reported in the GE literature. Microstructural examination revealed that the grains of the ceramic had fused together, with the metal having dewetted from the surface of the ceramic. Alternate substrates that might allow for better wetting of the metal on the ceramic such as LiFeO{sub 2} and Li{sub 2}MnO{sub 3} were identified. Cu/Ni-coated (50:50 mol ratio, 50 w/o metal loading) LiFeO{sub 2} anodes were optimized to meet the MCFC anode specifications. Metal-coated gamma-LiAlO{sub 2} substrates were also developed. By using suitable chemical surface modification methods, the gamma-UAlO{sub 2} substrate surface may be modified to allow a stable metal coated anode to be fabricated. Creep testing of the metal coated ceramic anodes were conducted at IGT. It was determined that the predominant creep mechanism is due to particle rearrangement. The anode porosity, and mean pore size had significant effect on the creep of the anode. Lower porosity and pore size consistent with performance criteria are desired to reduce creep. Lower metal loading with uniformity of coverage will result in lower creep behavior of the anode. Of the two substrates evaluated, LiFeO{sub 2} in general exhibited lower creep which was attributed to superior metal adhesion.

  8. Formulation design for orally disintegrating tablets containing enteric-coated particles.

    PubMed

    Okuda, Yutaka; Okamoto, Yasunobu; Irisawa, Yosuke; Okimoto, Kazuto; Osawa, Takashi; Yamashita, Shinji

    2014-01-01

    The purpose of this study was to investigate the applicability of our newly developed technology (RACTAB® technology) for preparing orally disintegrating tablets (ODTs) containing enteric-coated particles. Tamsulosin hydrochloride (TAM) was used as a model drug contained in the enteric-coated particles. Enteric-coated particles containing TAM (ECP-T) were prepared by spray coating a mixture of TAM with controlled-release materials. ECP-T was then mixed with rapidly disintegrating granules (RDGs), which were prepared using the suspension spray-coating method, and was tableted to form ODTs (ODTRAC). ODTRAC was evaluated for its hardness, thickness, internal structure (X-ray-CT scanning), functional properties (controlled-release profile), and in vivo disintegration time. Since RDGs with micronized ethylcellulose (MEC) increased tablet hardness by increasing the contact frequency between granules, ODTRAC containing ECP-T exhibited high hardness (>50 N) and low friability (<0.5%) with a relatively low compression force. After tableting, the structure of ECP-T in ODTRAC remained intact and no damage was observed on the surface. ECP-T recovered from ODTRAC showed the same dissolution profile of TAM in Japanese Pharmacopoeia (JP) 1st and JP 2nd media as that of intact ECP-T, which indicated that the tableting process did not affect the acid-resistibility of the particle. In addition, ODTRAC rapidly disintegrated in vivo (< 30 s), even at a high compression force (at 9 kN). These findings clearly suggest that RACTAB® technology is a useful approach to prepare ODTs containing enteric-coated particles.

  9. Field Evaluation of Particle Counter Technology for Aviation Fuel Contamination Detection - Fort Campbell

    DTIC Science & Technology

    2013-06-06

    fibrous materials, coatings material including paint, elastomeric materials, hydrocarbon/oxidation materials, and any other solid matter. At a...storage volume for CAA to 1.3M gallons. The fuel offloaded is not filtered prior to storage. JP-8 is transferred via a 0.5 mile underground pipeline

  10. Nuclear Energy Research Initiative Annual Report-Innovative Approaches to Automating QA/QC of Fuel Particle Production Using On-Line Nondestructive Methods for Higher Reliability.

    SciTech Connect

    Hockey, Ronald L.; Bond, Leonard J.; Ahmed, Salahuddin; Sandness, Gerald A.; Gray, Joseph N.; Batishko, Charles R.; Flake, Matthew; Panetta, Paul D.; Saurwein, John J.; Lowden, Richard A.; Good, Morris S.

    2004-04-20

    This document summarizes the activities performed and progress made in FY-03. Various approaches for automating the particle fuel production QC process using on-line nondestructive methods for higher reliability were evaluated. In this first-year of a three-year project, surrogate fuel particles made available for testing included leftovers from initial coater development runs. These particles had a high defect fraction and the particle properties spanned a wide range, providing the opportunity to examine worst-case conditions before refining the inspection methods to detect more subtle coating features. Particles specifically designed to evaluate the NDE methods being investigated under this project will be specified and fabricated at ORNL early next reporting period. The literature was reviewed for existing inspection technology and to identify many of the fuel particle conditions thought to degrade its performance. A modeling study, including the electromagnetic and techniques, showed that the in-line electromagnetic methods should provide measurable responses to missing layers, kernel diameter, and changes in coating layer thickness, with reasonable assumptions made for material conductivities. The modeling study for the ultrasonic methods provided the resonant frequencies that should be measured using the resonant ultrasound technique, and the results from these calculations were published in the proceedings for two conferences. The notion of a particle quality index to relate coating properties to fabrication process parameters was explored. Progress was made in understanding the fabrication process. GA identified key literature in this area and Saurwein (2003a) provided a literature review/summary. This literature has been reviewed. An approach previously applied to flexible manufacturing was adopted and the modification and development of the concepts to meet TRISO particle fuel manufacturing and QA/QC needs initiated. This approach establishes

  11. Fuel Property, Emission Test, and Operability Results from a Fleet of Class 6 Vehicles Operating on Gas-to-Liquid Fuel and Catalyzed Diesel Particle Filters

    SciTech Connect

    Alleman, T. L.; Eudy, L.; Miyasato, M.; Oshinuga, A.; Allison, S.; Corcoran, T.; Chatterjee, S.; Jacobs, T.; Cherrillo, R. A.; Clark, R.; Virrels, I.; Nine, R.; Wayne, S.; Lansing, R.

    2005-11-01

    A fleet of six 2001 International Class 6 trucks operating in southern California was selected for an operability and emissions study using gas-to-liquid (GTL) fuel and catalyzed diesel particle filters (CDPF). Three vehicles were fueled with CARB specification diesel fuel and no emission control devices (current technology), and three vehicles were fueled with GTL fuel and retrofit with Johnson Matthey's CCRT diesel particulate filter. No engine modifications were made.

  12. Individual particle morphology, coatings, and impurities of black carbon aerosols in Antarctic ice and tropical rainfall

    NASA Astrophysics Data System (ADS)

    Ellis, Aja; Edwards, Ross; Saunders, Martin; Chakrabarty, Rajan K.; Subramanian, R.; Timms, Nicholas E.; Riessen, Arie; Smith, Andrew M.; Lambrinidis, Dionisia; Nunes, Laurie J.; Vallelonga, Paul; Goodwin, Ian D.; Moy, Andrew D.; Curran, Mark A. J.; Ommen, Tas D.

    2016-11-01

    Black carbon (BC) aerosols are a large source of climate warming, impact atmospheric chemistry, and are implicated in large-scale changes in atmospheric circulation. Inventories of BC emissions suggest significant changes in the global BC aerosol distribution due to human activity. However, little is known regarding BC's atmospheric distribution or aged particle characteristics before the twentieth century. Here we investigate the prevalence and structural properties of BC particles in Antarctic ice cores from 1759, 1838, and 1930 Common Era (C.E.) using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The study revealed an unexpected diversity in particle morphology, insoluble coatings, and association with metals. In addition to conventionally occurring BC aggregates, we observed single BC monomers, complex aggregates with internally, and externally mixed metal and mineral impurities, tar balls, and organonitrogen coatings. The results of the study show BC particles in the remote Antarctic atmosphere exhibit complexity that is unaccounted for in atmospheric models of BC.

  13. Biofunctionalization of silica-coated magnetic particles mediated by a peptide

    NASA Astrophysics Data System (ADS)

    Care, Andrew; Chi, Fei; Bergquist, Peter L.; Sunna, Anwar

    2014-08-01

    A linker peptide sequence with affinity to silica-containing materials was fused to Streptococcus protein G', an antibody-binding protein. This recombinant fusion protein, linker-protein G (LPG) was produced in E. coli and exhibited strong affinity to silica-coated magnetic particles and was able to bind to them at different pHs, indicating a true pH-independent binding. LPG was used as an anchorage point for the oriented immobilization of antibodies onto the surface of the particles. These particle-bound "LPG-Antibody complexes" mediated the binding and recovery of different cell types (e.g., human stem cells, Legionella, Cryptosporidium and Giardia), enabling their rapid and simple visualization and identification. This strategy was used also for the efficient capture of Cryptosporidium oocysts from water samples. These results demonstrate that LPG can mediate the direct biofunctionalization of silica-coated magnetic particles without the need for complex surface chemical modification.

  14. Voids and yolk-shells from crystals that coat particles.

    PubMed

    Sindoro, Melinda; Granick, Steve

    2014-10-01

    We investigate curvature-driven core-shell morphology that emerges when polycrystalline shells of ZIF-8 (zeolitic imidazolate framework coordination polymer) grow on colloid-sized particles. In early growth stages, the shell is continuous, but it transforms to yolk-shell, with neither sacrificial template nor core etching, because of geometrical frustration. A design rule is developed regarding how local surface curvature matters. Comparing shells grown on cubic, rod-like, and peanut-shaped hematite core particles, we validate the argument.

  15. Passivation of pigment particles for thermal control coatings

    NASA Technical Reports Server (NTRS)

    Farley, E. P.; Sancier, K. M.; Morrison, S. R.

    1973-01-01

    Five powders were received for plasma calcining during this report period. The particle size using a fluid energy mill, and obtained pigments that could be plasma calcined. Optimum results are obtained in the plasma calcining of zinc orthotitanate when finely dispersed particles are subjected to a calculated plasma temperature of 1670 C. Increasing the plasma calcining time by using multiple passes through the plasma stabilized the pigment to vacuum UV irradiation was evidenced by the resulting ESR spectra but slightly decreased the whiteness of the pigment. The observed darkening is apparently associated with the formation of Ti(+3) color centers.

  16. Mesoporous silica coated silica-titania spherical particles: from impregnation to core-shell formation.

    PubMed

    Shiba, Kota; Takei, Toshiaki; Ogawa, Makoto

    2016-11-22

    The coating of solid surfaces with inorganic materials is a promising approach not only to impart various functionalities but also to modify physicochemical properties that are affected by the geometry/structure of the coating. In this study, a silica-hexadecyltrimethylammonium (silica-CTA) hybrid layer was deposited on monodispersed spherical particles composed of titania and octadecylamine (titania-ODA) by a sol-gel reaction of tetraethoxysilane in aqueous CTA/ammonia/methanol solution. The formation of the coating was confirmed by SEM and TEM observations. The coating thickness varied from a few nm to 100 nm depending on the Si/Ti ratio. We found that Si/Ti = 0.68 resulted in the formation of microporous silica-titania particles with the pore size of 0.7 nm as revealed by nitrogen adsorption/desorption measurements. Because the titania-ODA particles can be converted to mesoporous titania particles after removing ODA by acid/base treatment, the silica species can be impregnated into the titania particles and replace ODA under basic conditions. By increasing the Si/Ti molar ratio up to 1.4, silica-titania particles with non-porous structures were obtained. An amorphous to anatase transition occurred at around 800 °C, indicating the complete impregnation of silica inside the titania particles. Further increases of the Si/Ti molar ratio (to 3.4 and 6.8) led to the formation of the silica-CTA shell on the core particles, and the shell was converted to mesoporous silica layers with a pore size of 2 nm after calcination at 550 °C for 5 h. Non-linear control of the pore size/structure is presented for the first time; this will be useful for the precise design of diverse hybrid materials for optical, catalytic and biomedical applications.

  17. Dynamics of low velocity collisions of ice particle, coated with frost

    NASA Technical Reports Server (NTRS)

    Bridges, F.; Lin, D.; Boone, L.; Darknell, D.

    1991-01-01

    We continued our investigations of low velocity collisions of ice particles for velocities in range 10(exp -3) - 2 cm/s. The work focused on two effects: (1) the sticking forces for ice particles coated with CO2 frost, and (2) the completion of a 2-D pendulum system for glancing collisions. A new computer software was also developed to control and monitor the position of the 2-D pendulum.

  18. Coated or Embedded? Organic Matter as a Host for Individual Ambient Atmospheric Aerosol Particles (Invited)

    NASA Astrophysics Data System (ADS)

    Buseck, P. R.; Adachi, K.

    2009-12-01

    Organic matter is a prominent form of atmospheric aerosol particle. It commonly occurs with soot, sulfate, metals, or mineral dust in individual, internally mixed particles and is important when estimating radiative and health effects of aerosols. The details of these mini-assemblages are well observed when using transmission electron microscopy (TEM). When organic matter hosts soot particles, it enhances the light absorption of the soot and thus its warming effects. We determined the shapes of organic matter embedding soot using electron tomography (ET) with a transmission electron microscope, calculated the radiative forcing of such particles, and compared them to those of various coating and mixing models. Organic matter in particles collected from the vicinity of Mexico City (as part of the MILAGRO - Megacity Initiative: Local and Global Research Observations - campaign conducted in March 2006) also hosts metal-bearing nanoparticles that can include Fe, Zn, Mn, Pb, Hg, Sn, Cr, Ni, Ti, V, or Ag as major constituents. Nanoparticles of Hg are especially abundant. The nanoparticles are interesting because of their small sizes and high surface-to-volume ratios, both of which make them highly reactive in the human body and can cause negative health effects. In these and samples from other areas, we commonly find organic matter coating or otherwise associated with (hosting) inorganic aerosol particles of all types. Although the atmospheric community commonly speaks of coatings onto aerosol particles, in the case of organic matter, a more apt term might be embedding rather than coating. Finally, such hosting by organic matter can influence the climate and health effects of aerosol particles.

  19. Processing-microstructure-properties relationships in small-particle plasma-sprayed ceramic coatings

    NASA Astrophysics Data System (ADS)

    Mawdsley, Jennifer Renee

    The objective of this study was to determine processing-microstructure-properties relationships for small-particle plasma-sprayed (SPPS) ceramic coatings. Plasma-sprayed yttria partially-stabilized zirconia (YSZ) coatings, which are used to protect superalloys from heat and the environment in turbine engines, and plasma-sprayed alumina coatings, which are being investigated as a potential replacement for chrome in corrosion protection applications, were fabricated using SPPS technology and their microstructure and pertinent properties were examined. The properties of plasma-sprayed YSZ and alumina coatings were investigated with designed experiments. The parameters varied include power, spray distance, total plasma gas flow, percent hydrogen in the plasma gas, injector angle, injector offset and carrier gas flow. The variations in thermal diffusivity, thermal conductivity, elastic modulus, and hardness for the YSZ SPPS coatings were found to correlate to the variations in density, which were related to the processing variables. It was found that surface roughness was related to the amount of splashing and debris associated with the single splats. In four-point bending strain tolerance and fatigue tests, the SPPS YSZ coatings showed very little acoustic emission activity, except in the case of tensile fatigue of a coating without network cracks. Small angle X-ray scattering experiments revealed that SPPS YSZ coatings have significantly less submicron intersplat porosity than conventional plasma-sprayed coatings, and that the pore and microcrack scattering area decreases with heat treatment due to the sintering of microcracks and small pores. The SPPS alumina coatings were optimized to produce a coating with excellent corrosion protection capabilities. It was found that the hardest SPPS alumina coatings did not provide the best corrosion protection due to unique porosity defect structures associated with surface bumps in the coatings. The surface bumps were

  20. Contact Resistance and Metallurgical Connections Between Silver Coated Polymer Particles in Isotropic Conductive Adhesives

    NASA Astrophysics Data System (ADS)

    Pettersen, Sigurd R.; Kristiansen, Helge; Nagao, Shijo; Helland, Susanne; Njagi, John; Suganuma, Katsuaki; Zhang, Zhiliang; He, Jianying

    2016-07-01

    Recently, there has been an increasing interest in silver thin film coated polymer spheres as conductive fillers in isotropic conductive adhesives (ICAs). Such ICAs yield resistivities similar to conventional silver flake based ICAs while requiring only a fraction of the silver content. In this work, effects of the nanostructure of silver thin films on inter-particle contact resistance were investigated. The electrical resistivity of ICAs with similar particle content was shown to decrease with increasing coating thickness. Scanning electron micrographs of ion milled cross-sections revealed that the silver coatings formed continuous metallurgical connections at the contacts between the filler particles after adhesive curing at 150°C. The electrical resistivity decreased for all samples after environmental treatment for 3 weeks at 85°C/85% relative humidity. It was concluded that after the metallurgical connections formed, the bulk resistance of these ICAs were no longer dominated by the contact resistance, but by the geometry and nanostructure of the silver coatings. A figure of merit (FoM) was defined based on the ratio between bulk silver resistivity and the ICA resistivity, and this showed that although the resistivity was lowest in the ICAs containing the most silver, the volume of silver was more effectively used in the ICAs with intermediate silver contents. This was attributed to a size effect due to smaller grains in the thickest coating.

  1. Microstructure and thermal properties of copper–diamond composites with tungsten carbide coating on diamond particles

    SciTech Connect

    Kang, Qiping; He, Xinbo Ren, Shubin; Liu, Tingting; Liu, Qian; Wu, Mao; Qu, Xuanhui

    2015-07-15

    An effective method for preparing tungsten carbide coating on diamond surfaces was proposed to improve the interface bonding between diamond and copper. The WC coating was formed on the diamond surfaces with a reaction medium of WO{sub 3} in mixed molten NaCl–KCl salts and the copper–diamond composites were obtained by vacuum pressure infiltration of WC-coated diamond particles with pure copper. The microstructure of interface bonding between diamond and copper was discussed. Thermal conductivity and thermal expansion behavior of the obtained copper–diamond composites were investigated. Results indicated that the thermal conductivity of as-fabricated composite reached 658 W m{sup −} {sup 1} K{sup −} {sup 1}. Significant reduction in coefficient of thermal expansion of the composite compared with that of pure copper was obtained. - Highlights: • WC coating was successfully synthesized on diamond particles in molten salts. • WC coating obviously promoted the wettability of diamond and copper matrix. • WC coating greatly enhanced the thermal conductivity of Cu–diamond composite. • The composites are suitable candidates for heat sink applications.

  2. Boehmite particle coating modified microporous polyethylene membrane: A promising separator for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yang, Chongwen; Tong, Hua; Luo, Chuanpeng; Yuan, Shuanglong; Chen, Guorong; Yang, Yunxia

    2017-04-01

    To exploit high-quality separators for lithium ion batteries, current research activities are mainly focused on the modification of microporous polyolefin membranes by coating them with inorganic particles to achieve comprehensive improvements in their thermal stability, electrochemical compatibility, and overcharge protection. Here, we report a separator made by coating boehmite (AlOOH) particles on microporous polyethylene (PE) membranes. Compared to the commercially applied coating materials, e.g., aluminum oxide (Al2O3), AlOOH allows for a substantial reduction in the coating thickness, while ensuring excellent thermal stability of the modified PE membrane. Our study shows that this is due to the formation of an interlocking interface structure that interconnects the PE membrane and AlOOH coating layer as soon as PE melts at about 140 °C, preventing the modified PE membrane from shrinking at subsequently elevated temperatures. The modified PE membrane exhibits suitable electrolyte wettability to facilitate ion transport through it. Thus, the lithium ion batteries employing it as a separator could attain substantially improved electrochemical performance. Furthermore, the AlOOH-coated PE separator was also found to provide an excellent overcharge protection.

  3. An Investigation on Effects of TiO2 Nano-Particles Incorporated in Electroless NiP Coatings' Properties

    NASA Astrophysics Data System (ADS)

    Allahkaram, S. R.; Salmi, S.; Tohidlou, E.

    Electroless composite coatings have been vastly used in various industries during last decades due to their good properties, such as corrosion and wear resistance, hardness and uniform thickness. In this paper, co-deposition of TiO2 nano-particles with Nickel-Phosphorus electroless coatings on API-5L-X65 steel substrates was investigated. Surface morphology and composition of coatings were studied via SEM and EDX, respectively. XRD analyses showed that these coatings had amorphous structure with TiO2 crystalline particles. TiO2 nano-particles increased microhardness of coatings. Corrosion resistance of these coatings was tested using linear polarization in 0.5M sulfuric acid electrolyte. Results showed that NiP-TiO2 electroless composite coatings increased corrosion resistance of substrates.

  4. Nuclear Energy Research Initiative Project No. 02 103 Innovative Low Cost Approaches to Automating QA/QC of Fuel Particle Production Using On Line Nondestructive Methods for Higher Reliability Final Project Report

    SciTech Connect

    Ahmed, Salahuddin; Batishko, Charles R.; Flake, Matthew; Good, Morris S.; Mathews, Royce; Morra, Marino; Panetta, Paul D.; Pardini, Allan F.; Sandness, Gerald A.; Tucker, Brian J.; Weier, Dennis R.; Hockey, Ronald L.; Gray, Joseph N.; Saurwein, John J.; Bond, Leonard J.; Lowden, Richard A.; Miller, James H.

    2006-02-28

    This Nuclear Energy Research Initiative (NERI) project was tasked with exploring, adapting, developing and demonstrating innovative nondestructive test methods to automate nuclear coated particle fuel inspection so as to provide the United States (US) with necessary improved and economical Quality Assurance and Control (QA/QC) that is needed for the fuels for several reactor concepts being proposed for both near term deployment [DOE NE & NERAC, 2001] and Generation IV nuclear systems. Replacing present day QA/QC methods, done manually and in many cases destructively, with higher speed automated nondestructive methods will make fuel production for advanced reactors economically feasible. For successful deployment of next generation reactors that employ particle fuels, or fuels in the form of pebbles based on particles, extremely large numbers of fuel particles will require inspection at throughput rates that do not significantly impact the proposed manufacturing processes. The focus of the project is nondestructive examination (NDE) technologies that can be automated for production speeds and make either: (I) On Process Measurements or (II) In Line Measurements. The inspection technologies selected will enable particle “quality” qualification as a particle or group of particles passes a sensor. A multiple attribute dependent signature will be measured and used for qualification or process control decisions. A primary task for achieving this objective is to establish standard signatures for both good/acceptable particles and the most problematic types of defects using several nondestructive methods.

  5. Plasma polymerized allylamine coated quartz particles for humic acid removal.

    PubMed

    Jarvis, Karyn L; Majewski, Peter

    2012-08-15

    Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min. The influence of polymerization time on surface chemistry was investigated via X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectrometry (ToF-SIMS) and electrokinetic analysis. Acid orange 7 adsorption/desorption quantified the number of surface amine groups. Humic acid removal via ppAA quartz particles was examined by varying pH, removal time, humic acid concentration, and particle mass. Increasing the polymerization time increased the concentration of amine groups on the ppAA quartz surface, thus also increasing the isoelectric point. ToF-SIMS demonstrated uniform distribution of amine groups across the particle surface. Greatest humic acid removal was observed at pH 5 due to electrostatic attraction. At higher pH values, for longer polymerization times, humic acid removal was also observed due to hydrogen bonding. Increasing the initial humic acid concentration increased the mass of humic acid removed, with longer polymerization times exhibiting the greatest increases. Plasma polymerization using a rotating plasma reactor has shown to be a successful method for modifying quartz particles for the removal of humic acid. Further development of the plasma polymerization process and investigation of additional contaminants will aid in the development of a low cost water treatment system.

  6. Layer-by-layer self-assembly of ceramic particles for complex shape coating synthesis

    NASA Astrophysics Data System (ADS)

    Qiu, Hongwei

    Layer-by-layer (LbL) self-assembly was explored as a non-line-of-sight method for uniform infiltration and deposition of a multilayer of ceramic particles into complex structures. Key parameters for controlling the LbL self-assembly process were studied using a model system which consisted of a silicon substrate, 100 nm and 500 nm silica particles, and a polycation/polyanion combination. We correlated the surface coverage of the silica particles to the NaCl concentration used in deposition of the polyelectrolyte layers and to the number of the polyelectrolyte layers deposited. The effect of particle size on the surface coverage was rationally explained based on the screening length. We found that the effects of particle size, polydispersity, and electrolyte concentration in the particle suspension on the surface coverage and morphology of the first silica particle layer deposited on the polyelectrolyte layer surface were highly coupled, and resolving these effects was important for infiltrating a uniform coating of multilayer silica particle assemblies into a cellular structure as an ultimate complex substrate. Based on this understanding, the Lbl, self-assembly method was applied as a method of assembling, infiltrating, and immobilizing a 4-layer coating of negatively charged ˜3 mum Pd/NaAI(Si)O catalyst particles in the confined space of the cellular structure with ˜400 mum interconnected cells. The 4-layer coating deposited on the inner wall of a stainless steel capillary tube was mechanically stable under water flow rate up to 10 ml/min over the pH range of 3 to 11. Scotch tape peeling evaluation suggested that failure locations were mostly within the catalyst particle assembly, but near the assembly-PEM interface region.

  7. Experimental study of pine forest fuel layer ignition by the steel heated particle

    NASA Astrophysics Data System (ADS)

    Baranovskiy, Nikolay V.; Zakharevich, Arkadiy V.; Osotova, Diana S.

    2015-01-01

    Experimental research results of ignition processes of typical and widespread forest fuel (pine needles) by single heated up to high temperatures metal particles of the cylindrical form are presented. Ignition delays for particles of the various sizes and initial temperatures are resulted. Ignition conditions are established and a number of features of the investigated process mechanism are marked.

  8. Adaptive neuro-fuzzy inference system (ANFIS) to predict CI engine parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive neuro-fuzzy inference system (ANFIS) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For ANFIS modelling, Gaussian curve membership function (gaussmf) and 200 training epochs (iteration) were found to be optimum choices for training process. The results demonstrate that ANFIS is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve combustion of the fuel and reduce the exhaust emissions significantly.

  9. A Novel Strategy for Bitter Taste Masking of Gankeshuangqing Dispersible Tablets Based on Particle Coating Technology.

    PubMed

    Han, Xue; Zhang, Ding-Kun; Zhang, Fang; Lin, Jun-Zhi; Jiang, Hong; Lan, Yang; Xiong, Xi; Han, Li; Yang, Ming; Fu, Chao-Mei

    2017-01-01

    Currently, acute upper respiratory tract infections (AURTIs) are increasingly becoming a significant health burden. Gankeshuangqing dispersible tablets (GKSQDT) which have a good effect on treating AURTIs. GKSQDT is composed of baicalin and andrographolide. However, its severe bitterness limits application of patients. Due to the addition of plentiful accessories, common masking methods are unsuitable for GKSQDT. It is thus necessary to develop a new masking method. The Previous study showed that baicalin was less bitter than andrographolide. Thus, particle coating technology was adapted to prepare composite particles that baicalin coated on the surface of andrographolide to decrease bitterness. Initially, particle size of baicalin and coating time of composite was investigated to prepare composite. Then, scanning electron microscopy, wettability, and infrared (IR) spectrogram were used to characterize the microstructure of composite. Furthermore, electronic tongue test, animal preference experiment, and human sensory test were applied to evaluate the masking effect. To produce composite, baicalin should be ground in vibromill for 6 min. Then, andrographolide fine powder was added to grind together for 6 min. Contact angle of composite was smaller than mixture, and more similar to baicalin. Other physical characterization including microstructure, wettability, and IR also suggested that andrographolide was successfully coated by baicalin superfine. Furthermore, taste-masking test indicated taste-masked tablets was less bitter than original tablets. The study indicated that particle coating technology can be used for taste masking of GKSQDT without adding other substance. Moreover, it provides a new strategy of taste masking for national medicine. A new strategy to mask bitterness without adding any other substance based on coating technology was providedThe masking effect was confirmed by electronic tongue test, animal preference experiment and human sensory test

  10. A Novel Strategy for Bitter Taste Masking of Gankeshuangqing Dispersible Tablets Based on Particle Coating Technology

    PubMed Central

    Han, Xue; Zhang, Ding-Kun; Zhang, Fang; Lin, Jun-Zhi; Jiang, Hong; Lan, Yang; Xiong, Xi; Han, Li; Yang, Ming; Fu, Chao-Mei

    2017-01-01

    Background: Currently, acute upper respiratory tract infections (AURTIs) are increasingly becoming a significant health burden. Gankeshuangqing dispersible tablets (GKSQDT) which have a good effect on treating AURTIs. GKSQDT is composed of baicalin and andrographolide. However, its severe bitterness limits application of patients. Due to the addition of plentiful accessories, common masking methods are unsuitable for GKSQDT. It is thus necessary to develop a new masking method. Materials and Methods: The Previous study showed that baicalin was less bitter than andrographolide. Thus, particle coating technology was adapted to prepare composite particles that baicalin coated on the surface of andrographolide to decrease bitterness. Initially, particle size of baicalin and coating time of composite was investigated to prepare composite. Then, scanning electron microscopy, wettability, and infrared (IR) spectrogram were used to characterize the microstructure of composite. Furthermore, electronic tongue test, animal preference experiment, and human sensory test were applied to evaluate the masking effect. Results: To produce composite, baicalin should be ground in vibromill for 6 min. Then, andrographolide fine powder was added to grind together for 6 min. Contact angle of composite was smaller than mixture, and more similar to baicalin. Other physical characterization including microstructure, wettability, and IR also suggested that andrographolide was successfully coated by baicalin superfine. Furthermore, taste-masking test indicated taste-masked tablets was less bitter than original tablets. Conclusion: The study indicated that particle coating technology can be used for taste masking of GKSQDT without adding other substance. Moreover, it provides a new strategy of taste masking for national medicine. SUMMARY A new strategy to mask bitterness without adding any other substance based on coating technology was providedThe masking effect was confirmed by electronic

  11. Abrasive wear by coal-fueled diesel engine and related particles

    SciTech Connect

    Ives, L.K.

    1992-09-01

    The development of commercially viable diesel engines that operate directly on pulverized coal-fuels will require solution to the problem of severe abrasive wear. The purpose of the work described in this report was to investigate the nature of the abrasive wear problem. Analytical studies were carried out to determine the characteristics of the coal-fuel and associated combustion particles responsible for abrasion. Laboratory pinon-disk wear tests were conducted on oil-particle mixtures to determine the relationship between wear rate and a number of different particle characteristics, contact parameters, specimen materials properties, and other relevant variables.

  12. Abrasive wear by coal-fueled diesel engine and related particles

    SciTech Connect

    Ives, L.K. )

    1992-09-01

    The development of commercially viable diesel engines that operate directly on pulverized coal-fuels will require solution to the problem of severe abrasive wear. The purpose of the work described in this report was to investigate the nature of the abrasive wear problem. Analytical studies were carried out to determine the characteristics of the coal-fuel and associated combustion particles responsible for abrasion. Laboratory pinon-disk wear tests were conducted on oil-particle mixtures to determine the relationship between wear rate and a number of different particle characteristics, contact parameters, specimen materials properties, and other relevant variables.

  13. Wire rod coating process of gas diffusion layers fabrication for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Kannan, A. M.; Sadananda, S.; Parker, D.; Munukutla, L.; Wertz, J.; Thommes, M.

    Gas diffusion layers (GDLs) were fabricated using non-woven carbon paper as a macro-porous layer substrate developed by Hollingsworth & Vose Company. A commercially viable coating process was developed using wire rod for coating micro-porous layer by a single pass. The thickness as well as carbon loading in the micro-porous layer was controlled by selecting appropriate wire thickness of the wire rod. Slurry compositions with solid loading as high as 10 wt.% using nano-chain and nano-fiber type carbons were developed using dispersion agents to provide cohesive and homogenous micro-porous layer without any mud-cracking. The surface morphology, wetting characteristics and pore size distribution of the wire rod coated GDLs were examined using FESEM, Goniometer and Hg porosimetry, respectively. The GDLs were evaluated in single cell PEMFC under various operating conditions (temperature and RH) using hydrogen and air as reactants. It was observed that the wire rod coated micro-porous layer with 10 wt.% nano-fibrous carbon based GDLs showed the highest fuel cell performance at 85 °C using H 2 and air at 50% RH, compared to all other compositions.

  14. Diffusion Barrier Properties of Nitride-Based Coatings on Fuel Cladding

    SciTech Connect

    Fauzia Khatkhatay; Jie Jian; Liang Jiao; Qing Su; Jian Gan; James I. Cole; Haiyan Wang

    2013-12-01

    In this work titanium nitride (TiN) and zirconium nitride (ZrN) coatings are proposed as diffusion barriers between stainless steel nuclear fuel cladding and lanthanide fission products. TiN and ZrN have been coated as barrier materials between pure Fe and Ce, i.e. diffusion couples of Fe/TiN/Ce and Fe/ZrN/Ce, annealed up to a temperature of 600 degrees C, and compared to the diffusion behavior of uncoated Fe/Ce. Backscattered electron images and electron dispersive X-ray spectroscopy measurements confirm that, with a 500 nm TiN or ZrN layer, no obvious diffusion is observed between Fe and Ce. Basic diffusion characteristics of the Fe/Ce couple have also been measured and compared with the TiN and ZrN coated ones. The results strongly advocate that TiN and ZrN coatings provide reliable diffusion barrier characteristics against Ce and possibly other lanthanide fission products.

  15. Electrochemical behavior of zinc particles with silica based coatings as anode material for zinc air batteries with improved discharge capacity

    NASA Astrophysics Data System (ADS)

    Schmid, M.; Willert-Porada, M.

    2017-05-01

    Silica coatings on zinc particles as anode material for alkaline zinc air batteries are expected to reduce early formation of irreversible ZnO passivation layers during discharge by controlling zinc dissolution and precipitation of supersaturated zincates, Zn(OH)42-. Zinc particles were coated with SiO2 (thickness: 15 nm) by chemical solution deposition and with Zn2SiO4 (thickness: 20 nm) by chemical vapor deposition. These coatings formed a Si(OH)4 gel in aqueous KOH and retarded hydrogen evolution by 40%. By treatment in aqueous KOH and drying afterwards, the silica coatings were changed into ZnO-K2O·SiO2 layers. In this work, the electrochemical performance of such coated zinc particles is investigated by different electrochemical methods in order to gain a deeper understanding of the mechanisms of the coatings, which reduce zinc passivation. In particular, zinc utilization and changes in internal resistance are investigated. Moreover, methods for determination of diffusion coefficients, charge carrier numbers and activation energies for electrochemical oxidation are determined. SiO2-coated zinc particles show improved discharge capacity (CVD-coated zinc: 69% zinc utilization, CSD-coated zinc: 62% zinc utilization) as compared to as-received zinc (57% zinc utilization) at C/20 rate, by reducing supersaturation of zincates. Additionally, KOH-modified SiO2-coated zinc particles enhance rechargeability after 100% depth-of-discharge.

  16. Size distribution of EC, OC and particle-phase PAHs emissions from a diesel engine fueled with three fuels.

    PubMed

    Lu, Tian; Huang, Zhen; Cheung, C S; Ma, Jing

    2012-11-01

    The size distribution of elemental carbon (EC), organic carbon (OC) and particle-phase PAHs emission from a direct injection diesel engine fueled with a waste cooking biodiesel, ultra low sulfur diesel (ULSD, 10-ppm-wt), and low sulfur diesel (LSD, 400-ppm-wt) were investigated experimentally. The emission factor of biodiesel EC is 90.6 mg/kh, which decreases by 60.3 and 71.7%, compared with ULSD and LSD respectively and the mass mean diameter (MMD) of EC was also decreased with the use of biodiesel. The effect of biodiesel on OC emission might depend on the engine operation condition, and the difference in OC size distribution is not that significant among the three fuels. For biodiesel, its brake specific emission of particle-phase PAHs is obviously smaller than that from the two diesel fuels, and the reduction effect appears in almost all size ranges. In terms of size distribution, the MMD of PAHs from biodiesel is larger than that from the two diesel fuels, which could be attributed to the more effective reduction on combustion derived PAHs in nuclei mode. The toxicity analysis indicates that biodiesel could reduce the total PAHs emissions, as well as the carcinogenic potency of particle-phase PAHs in almost all the size ranges.

  17. Particle interactions of polyvinylpyrrolidone-coated iron oxide particles as magnetic drug delivery agents

    NASA Astrophysics Data System (ADS)

    İşçi, Sevim; İşçi, Yavuz; Bekaroğlu, Maide Gökçe

    2017-08-01

    Iron oxide particles have been recently researched for the potential applications of targeted drug delivery due to their magnetic properties. The surfaces of the iron oxide particles must be modified to reduce the toxicity and to load the drug to the particles. Biopolymers are good surface modifiers of colloidal particles such as iron oxide particles. The degree of surface coverage of the colloidal iron oxide particles affects the stability, toxicity, magnetic properties and drug loading efficiency. In this study, the interactions of iron oxide (Fe3O4) particles and PVP were determined according to the colloidal properties. The proper concentration of PVP for the whole coverage of the iron oxide particles was found for the possible magnetic drug delivery applications by controlling the colloidal properties of the dispersions. The magnetic properties and toxicity of the fully covered bioiron oxide was also determined for possible applications.

  18. Impact of Sodium Humate Coating on Collector Surfaces on Deposition of Polymer-Coated Nanoiron Particles.

    PubMed

    Micić, Vesna; Schmid, Doris; Bossa, Nathan; Gondikas, Andreas; Velimirovic, Milica; von der Kammer, Frank; Wiesner, Mark R; Hofmann, Thilo

    2017-08-15

    The affinity between nanoscale zerovalent iron (nano-ZVI) and mineral surfaces hinders its mobility, and hence its delivery into contaminated aquifers. We have tested the hypothesis that the attachment of poly(acrylic acid)-coated nano-ZVI (PAA-nano-ZVI) to mineral surfaces could be limited by coating such surfaces with sodium (Na) humate prior to PAA-nano-ZVI injection. Na humate was expected to form a coating over favorable sites for PAA-nano-ZVI attachment and hence reduce the affinity of PAA-nano-ZVI for the collector surfaces through electrosteric repulsion between the two interpenetrating charged polymers. Column experiments demonstrated that a low concentration (10 mg/L) Na humate solution in synthetic water significantly improved the mobility of PAA-nano-ZVI within a standard sand medium. This effect was, however, reduced in more heterogeneous natural collector media from contaminated sites, as not an adequate amount of the collector sites favorable for PAA-nano-ZVI attachment within these media appear to have been screened by the Na humate. Na humate did not interact with the surfaces of acid-washed glass beads or standard Ottawa sand, which presented less surface heterogeneity. Important factors influencing the effectiveness of Na humate application in improving PAA-nano-ZVI mobility include the solution chemistry, the Na humate concentration, and the collector properties.

  19. Raman sensing of fuel gases using a reflective coating capillary optical fiber

    NASA Astrophysics Data System (ADS)

    Buric, M. P.; Chen, K.; Falk, J.; Velez, R.; Woodruff, S.

    2009-05-01

    Hollow core fiber optics enable gas phase Raman spectroscopy with relatively low power laser excitation sources. A Raman sensor for gaseous fuel analysis is demonstrated using silver coated capillary optical fiber as the sample cell and as the signal collection optic. Using laser powers with as little as a few milliwatts excitation power, the majority species of natural gas and syngas are readily detected, as well as oxygen and nitrogen in a single sensor system. Exchange rates in the capillary optical fiber are high enough to enable optical analysis in sub-second response time for real time sensing and control. Because this one sensor system simultaneously detects and resolves all the component species, real time feedback to the combustion control system of fuel content and properties is enabled.

  20. Near-frictionless carbon coatings for spark-ignited direct-injected fuel systems. Final report, January 2002.

    SciTech Connect

    Hershberger, J.; Ozturk, O.; Ajayi, O. O.; Woodford, J. B.; Erdemir, A.; Fenske, G. R.

    2002-04-05

    This report describes an investigation by the Tribology Section of Argonne National Laboratory (ANL) into the use of near-frictionless carbon (NFC) coatings for spark-ignited, direct-injected (SIDI) engine fuel systems. Direct injection is being pursued in order to improve fuel efficiency and enhance control over, and flexibility of, spark-ignited engines. SIDI technology is being investigated by the Partnership for a New Generation of Vehicles (PNGV) as one route towards meeting both efficiency goals and more stringent emissions standards. Friction and wear of fuel injector and pump parts were identified as issues impeding adoption of SIDI by the OTT workshop on ''Research Needs Related to CIDI and SIDI Fuel Systems'' and the resulting report, Research Needs Related to Fuel Injection Systems in CIDI and SIDI Engines. The following conclusions were reached: (1) Argonne's NFC coatings consistently reduced friction and wear in existing and reformulated gasolines. (2) Compared to three commercial DLC coatings, NFC provided the best friction reduction and protection from wear in gasoline and alternative fuels. (3) NFC was successfully deposited on production fuel injectors. (4) Customized wear tests were performed to simulate the operating environment of fuel injectors. (5) Industry standard lubricity test results were consistent with customized wear tests in showing the friction and wear reduction of NFC and the lubricity of fuels. (6) Failure of NFC coatings by tensile crack opening or spallation did not occur, and issues with adhesion to steel substrates were eliminated. (7) This work addressed several of the current research needs of the OAAT SIDI program, as defined by the OTT report Research Needs Related to Fuel Injection Systems in CIDI and SIDI Engines.

  1. Kinetics of fuel particle weathering and {sup 90}Sr mobility in the Chernobyl 30-km exclusion zone

    SciTech Connect

    Kashparov, V.A.; Zvarich, S.I.; Protsak, V.P.; Levchuk, S.E.; Oughton, D.H.

    1999-03-01

    Weathering of fuel particles and the subsequent leaching of radionuclides causes {sup 90}Sr mobility in Chernobyl soils to increase with time after disposition. Studies of {sup 90}Sr speciation in soils collected in 1995 and 1996 from the Chernobyl 30-km exclusion zone have been used to calculate rates of fuel particles dissolution under natural environmental conditions. Results show that the velocity of fuel particle dissolution is primarily dependent on the physico-chemical characteristics of the particles and partially dependent on soil acidity. Compared to other areas, the fuel particle dissolution rate is significantly lower in the contaminated areas to the west of the Chernobyl reactor where deposited particles were presumably not oxidized prior to release. The data have been used to derive mathematical models that describe the rate of radionuclide leaching from fuel particles in the exclusion zone and changes in soil-to-plant transfer as a function of particle type and soil pH.

  2. Abrasive wear by diesel engine coal-fuel and related particles

    SciTech Connect

    Ives, L.K.

    1994-09-01

    The purpose of the work summarized in this report was to obtain a basic understanding of the factors which are responsible for wear of the piston ring and cylinder wall surfaces in diesel engines utilizing coal-fuel. The approach included analytical studies using scanning electron microscopy and energy dispersive x-ray analyses to characterize coal-fuel and various combustion particles, and two different wear tests. The wear tests were a modified pin-on-disk test and a block-on-ring test capable of either unidirectional or reciprocating-rotational sliding. The wear tests in general were conducted with mixtures of the particles and lubricating oil. The particles studied included coal-fuel, particles resulting from the combustion of coal fuel, mineral matter extracted during the processing of coal, and several other common abrasive particle types among which quartz was the most extensively examined. The variables studied included those associated with the particles, such as particle type, size, and hardness; variables related to contact conditions and the surrounding environment; and variables related to the type and properties of the test specimen materials.

  3. Core Fueling and Edge Particle Flux Analysis in Ohmically and Auxiliary Heated NSTX Plasmas

    SciTech Connect

    V.A. Soukhanovskii; R. Maingi; R. Raman; H.W. Kugel; B.P. LeBlanc; L. Roquemore; C.H. Skinner; NSTX Research Team

    2002-06-12

    The Boundary Physics program of the National Spherical Torus Experiment (NSTX) is focusing on optimization of the edge power and particle flows in b * 25% L- and H-mode plasmas of t {approx} 0.8 s duration heated by up to 6 MW of high harmonic fast wave and up to 5 MW of neutral beam injection. Particle balance and core fueling efficiencies of low and high field side gas fueling of L-mode homic and NBI heated plasmas have been compared using an analytical zero dimensional particle balance model and measured ion and neutral fluxes. Gas fueling efficiencies are in the range of 0.05-0.20 and do not depend on discharge magnetic configuration, density or poloidal location of the injector. The particle balance modeling indicates that the addition of HFS fueling results in a reversal of the wall loading rate and higher wall inventories. Initial particle source estimates obtained from neutral pressure and spectroscopic measurements indicate that ion flux into the divertor greatly exceeds midplane ion flux from the main plasma, suggesting that the scrape-off cross-field transport plays a minor role in diverted plasmas. Present analysis provides the basis for detailed fluid modeling of core and edge particle flows and particle confinement properties of NSTX plasmas. This research was supported by the U.S. Department of Energy under contracts No. DE-AC02-76CH03073, DE-AC05-00OR22725, and W-7405-ENG-36.

  4. A facile approach towards amino-coated polyethersulfone particles for the removal of toxins.

    PubMed

    Song, Xin; Wang, Rui; Zhao, Weifeng; Sun, Shudong; Zhao, Changsheng

    2017-01-01

    The removal of toxins is important due to the damage to aquatic environment. In this work, a facile and green approach based on mussel-inspired coatings was used to fabricate amino-coated particles via the reaction between amine and catechol, using hexanediamine as the representative amine. The particles were characterized by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). The particles showed selective adsorption capability to Congo red (CR) and the adsorption process fitted the pseudo-second-order model, the intraparticle diffusion model, the Langmuir isotherm, the Freundlich isotherm and the Sips isotherm well. Furthermore, this approach was verified to have applicability to various amines such as diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), and the amino-coated particles exhibited diverse adsorption capacities to CR, Cu(2+) and bilirubin. Considering that the approach is easy to operate and the whole preparation process is in an aqueous solution, it is believed that the facile, green and economical approach has great potential to prepare particles for wastewater treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Electroless nickel - phosphorus coating on crab shell particles and its characterization

    NASA Astrophysics Data System (ADS)

    Arulvel, S.; Elayaperumal, A.; Jagatheeshwaran, M. S.

    2017-04-01

    Being hydrophilic material, crab shell particles have only a limited number of applications. It is, therefore, necessary to modify the surface of the crab shell particles. To make them useful ever for the applications, the main theme we proposed in this article is to utilize crab shell particles (CSP) with the core coated with nickel phosphorus (NiP) as a shell using the electroless coating process. For dealing with serious environmental problems, utilization of waste bio-shells is always an important factor to be considered. Chelating ability of crab shell particles eliminates the surface activation in this work proceeding to the coating process. The functional group, phase structure, microstructure, chemical composition and thermal analysis of CSP and NiP/CSP were characterized using Fourier transform infra-red spectroscopy (FTIR), x-ray diffraction analyzer (XRD), scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The combination of an amorphous and crystalline structure was exhibited by CSP and NiP/CSP. NiP/CSP has shown a better thermal stability when compared to uncoated CSP. Stability test, adsorption test, and conductivity test were conducted for the study of adsorption behavior and conductivity of the particles. CSP presented a hydrophilic property in contrast to hydrophobic NiP/CSP. NiP/CSP presented a conductivity of about 44% greater compared to the CSP without any fluctuations.

  6. Structure zone diagram and particle incorporation of nickel brush plated composite coatings

    PubMed Central

    Isern, L.; Impey, S.; Almond, H.; Clouser, S. J.; Endrino, J. L.

    2017-01-01

    This work studies the deposition of aluminium-incorporated nickel coatings by brush electroplating, focusing on the electroplating setup and processing parameters. The setup was optimised in order to increase the volume of particle incorporation. The optimised design focused on increasing the plating solution flow to avoid sedimentation, and as a result the particle transport experienced a three-fold increase when compared with the traditional setup. The influence of bath load, current density and the brush material used was investigated. Both current density and brush material have a significant impact on the morphology and composition of the coatings. Higher current densities and non-abrasive brushes produce rough, particle-rich samples. Different combinations of these two parameters influence the surface characteristics differently, as illustrated in a Structure Zone Diagram. Finally, surfaces featuring crevices and peaks incorporate between 3.5 and 20 times more particles than smoother coatings. The presence of such features has been quantified using average surface roughness Ra and Abbott-Firestone curves. The combination of optimised setup and rough surface increased the particle content of the composite to 28 at.%. PMID:28300159

  7. Structure zone diagram and particle incorporation of nickel brush plated composite coatings

    NASA Astrophysics Data System (ADS)

    Isern, L.; Impey, S.; Almond, H.; Clouser, S. J.; Endrino, J. L.

    2017-03-01

    This work studies the deposition of aluminium-incorporated nickel coatings by brush electroplating, focusing on the electroplating setup and processing parameters. The setup was optimised in order to increase the volume of particle incorporation. The optimised design focused on increasing the plating solution flow to avoid sedimentation, and as a result the particle transport experienced a three-fold increase when compared with the traditional setup. The influence of bath load, current density and the brush material used was investigated. Both current density and brush material have a significant impact on the morphology and composition of the coatings. Higher current densities and non-abrasive brushes produce rough, particle-rich samples. Different combinations of these two parameters influence the surface characteristics differently, as illustrated in a Structure Zone Diagram. Finally, surfaces featuring crevices and peaks incorporate between 3.5 and 20 times more particles than smoother coatings. The presence of such features has been quantified using average surface roughness Ra and Abbott-Firestone curves. The combination of optimised setup and rough surface increased the particle content of the composite to 28 at.%.

  8. On the constitutive relations for catalyst coated membrane applied to in-situ fuel cell modeling

    NASA Astrophysics Data System (ADS)

    Khorasany, Ramin M. H.; Goulet, Marc-Antoni; Alavijeh, Alireza Sadeghi; Kjeang, Erik; Wang, G. Gary; Rajapakse, R. K. N. D.

    2014-04-01

    The elastic-viscoplastic behavior of catalyst coated membranes (CCMs) used in polymer electrolyte membrane fuel cells is investigated in this work. Experimental results reveal significant differences between the mechanical properties of a pure perfluorosulfonic acid ionomer membrane and the corresponding CCM under uniaxial tension and cyclic loading. An elastic-viscoplastic constitutive model that is capable of capturing the time dependent response of the CCM at different humidity and temperature conditions is developed and validated against ex-situ experimental results. The validated model is then utilized to simulate the in-situ mechanical response of the CCM when treated as a composite object bonded through the ionomer phase. When compared to a conventional membrane model, the CCM model predicts considerably lower maximum stress and higher plastic strain under typical fuel cell operating conditions and improved plastic strain recovery during hygrothermal unloading. These results reflect the weaker nature of the CCM material which yields at a lower stress than the membrane and may lead to elevated plastic deformation when exposed to hygrothermal cycles in a constrained fuel cell environment. Hence, coupled CCM implementation is generally recommended for finite element modeling of fuel cells.

  9. Microexplosions and ignition dynamics in engineered aluminum/polymer fuel particles

    DOE PAGES

    Rubio, Mario A.; Gunduz, I. Emre; Groven, Lori J.; ...

    2016-11-11

    Aluminum particles are widely used as a metal fuel in solid propellants. However, poor combustion efficiencies and two-phase flow losses result due in part to particle agglomeration. Engineered composite particles of aluminum (Al) with inclusions of polytetrafluoroethylene (PTFE) or low-density polyethylene (LDPE) have been shown to improve ignition and yield smaller agglomerates in solid propellants, recently. Reductions in agglomeration were attributed to internal pressurization and fragmentation (microexplosions) of the composite particles at the propellant surface. We explore the mechanisms responsible for microexplosions in order to better understand the combustion characteristics of composite fuel particles. Single composite particles of Al/PTFE andmore » Al/LDPE with diameters between 100 and 1200 µm are ignited on a substrate to mimic a burning propellant surface in a controlled environment using a CO2 laser in the irradiance range of 78–7700 W/cm2. Furthermore, the effects of particle size, milling time, and inclusion content on the resulting ignition delay, product particle size distributions, and microexplosion tendencies are reported. For example particles with higher PTFE content (30 wt%) had laser flux ignition thresholds as low as 77 W/cm2, exhibiting more burning particle dispersion due to microexplosions compared to the other materials considered. Composite Al/LDPE particles exhibit relatively high ignition thresholds compared to Al/PTFE particles, and microexplosions were observed only with laser fluxes above 5500 W/cm2 due to low LDPE reactivity with Al resulting in negligible particle self-heating. However, results show that microexplosions can occur for Al containing both low and high reactivity inclusions (LDPE and PTFE, respectively) and that polymer inclusions can be used to tailor the ignition threshold. Furthermore, this class of modified metal particles shows significant promise for application in many different energetic materials

  10. Microexplosions and ignition dynamics in engineered aluminum/polymer fuel particles

    SciTech Connect

    Rubio, Mario A.; Gunduz, I. Emre; Groven, Lori J.; Sippel, Travis R.; Han, Chang Wan; Unocic, Raymond R.; Ortalan, Volkan; Son, Steven F.

    2016-11-11

    Aluminum particles are widely used as a metal fuel in solid propellants. However, poor combustion efficiencies and two-phase flow losses result due in part to particle agglomeration. Engineered composite particles of aluminum (Al) with inclusions of polytetrafluoroethylene (PTFE) or low-density polyethylene (LDPE) have been shown to improve ignition and yield smaller agglomerates in solid propellants, recently. Reductions in agglomeration were attributed to internal pressurization and fragmentation (microexplosions) of the composite particles at the propellant surface. We explore the mechanisms responsible for microexplosions in order to better understand the combustion characteristics of composite fuel particles. Single composite particles of Al/PTFE and Al/LDPE with diameters between 100 and 1200 µm are ignited on a substrate to mimic a burning propellant surface in a controlled environment using a CO2 laser in the irradiance range of 78–7700 W/cm2. Furthermore, the effects of particle size, milling time, and inclusion content on the resulting ignition delay, product particle size distributions, and microexplosion tendencies are reported. For example particles with higher PTFE content (30 wt%) had laser flux ignition thresholds as low as 77 W/cm2, exhibiting more burning particle dispersion due to microexplosions compared to the other materials considered. Composite Al/LDPE particles exhibit relatively high ignition thresholds compared to Al/PTFE particles, and microexplosions were observed only with laser fluxes above 5500 W/cm2 due to low LDPE reactivity with Al resulting in negligible particle self-heating. However, results show that microexplosions can occur for Al containing both low and high reactivity inclusions (LDPE and PTFE, respectively) and that polymer inclusions can be used to tailor the ignition threshold. Furthermore, this class of modified metal particles shows significant promise for application in

  11. The Corrosion and Wear Performance of Microcrystalline WC-10Co-4Cr and Near-Nanocrystalline WC-17Co High Velocity Oxy-Fuel Sprayed Coatings on Steel Substrate

    NASA Astrophysics Data System (ADS)

    Saha, Gobinda C.; Khan, Tahir I.

    2010-11-01

    The study of near-nanocrystalline cermet composite coating was performed by depositing near-nanocrystalline WC-17Co powder using the high velocity oxy-fuel spraying technique. The WC-17Co powder consists of a core with an engineered near-nano-scale WC dispersion with a mean grain size 427 nm. The powder particle contains 6 wt pct of the ductile phase Co matrix mixed into the core to ensure that the reinforcing ceramic phase WC material is discontinuous to limit debridement during wear, while the remainder of the binding phase (11 wt pct) is applied as a coating on the powder particle to improve the ductility. The tribological properties of the coating, in terms of corrosion resistance, microhardness, and sliding abrasive wear, were studied and compared with those of an industrially standard microcrystalline WC-10Co-4Cr coating with a WC mean grain size 3 μm. Results indicated that the WC-17Co coating had superior wear and corrosion resistance compared to the WC-10Co-4Cr coating. The engineered WC-17Co powder with a duplex Co layer had prevented significant decarburization of the WC dispersion in the coating, thereby reducing the intersplat microporosity necessary for initiating microgalvanic cells. The improved wear resistance was attributed to the higher hardness value of the near-nanocrystalline WC-17Co coating.

  12. Electron microscopy structure study of laser-clad TiC-Ni particle-reinforced coating

    SciTech Connect

    Ouyang, J.H.; Li, X.; Lei, T.C.

    2000-04-01

    The microstructure of a laser-clad TiC-Ni particle-reinforced coating on 1045 steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ion microprobe mass spectroscopy (IMMS). The microstructural constituents of the clad layers (CLs) were analyzed to be TiC particles, {gamma}-Ni primary dendrites, and interdendritic eutectics of {gamma}{sub E}-Ni plus M{sub 23}(CB){sub 6} and M{sub 6}(CB) carboborides. Three growth mechanisms of the original TiC particles were found: (1) stepped lateral growth at the edges, (2) radiated and cylindrically coupled growth at the edges, and (3) bridging growth of the clustered particles. Ordered and modulated structures were found in the original TiC particles. In addition to the original TiC particles, fine TiC particles precipitated from the liquid phase and {gamma}-Ni solid solution during laser cladding. The microstructures of the bonding zones (BZs) were intimately associated with laser processing parameters. The BZs of the clad coatings can be categorized into three types according to the combination of the CL with heat-affected zone (HAZ): (1) straight interface combination, (2) zigzag connection, and (3) combination by partial melting of prior austenitic grain boundaries of the substrate. The microstructural evolution of the CLs was discussed. The formation and phase transformation models of the BZs were proposed.

  13. Deposition and properties of high-velocity-oxygen-fuel and plasma-sprayed Mo-Mo2C composite coatings

    NASA Astrophysics Data System (ADS)

    Prchlik, L.; Gutleber, J.; Sampath, S.

    2001-12-01

    Molybdenum thermal-spray coatings, dispersion strengthened by molybdenum oxides and molybdenum carbides, play an important role in industrial tribological applications. Traditionally, they have been prepared by plasma and wire flame spraying. High porosity and lower cohesion strength limit their application in situations where both galling and abrasion wear is involved. In this study, high-velocity-oxygen-fuel (HVOF) deposition of molybdenum and molybdenum carbide coatings was attempted. Deposition was achieved for all powders used. Composition, microstructure, mechanical, and wear properties of the HVOF synthesized coatings were evaluated and compared with plasma-sprayed counterparts. The HVOF coatings possessed a very good abrasion resistance, whereas plasma deposits performed better in dry sliding tests. Measurements showed a close relationship between the coating surface hardness and its abrasion resistance. Results also suggested correlation between molybdenum carbide distribution in the molybdenum matrix and the sliding friction response of Mo-Mo2C coatings.

  14. Advanced oxidation of natural organic matter using hydrogen peroxide and iron-coated pumice particles.

    PubMed

    Kitis, M; Kaplan, S S

    2007-08-01

    The oxidative removal of natural organic matter (NOM) from waters using hydrogen peroxide and iron-coated pumice particles as heterogeneous catalysts was investigated. Two NOM sources were tested: humic acid solution and a natural source water. Iron coated pumice removed about half of the dissolved organic carbon (DOC) concentration at a dose of 3000 mg l(-1) in 24 h by adsorption only. Original pumice and peroxide dosed together provided UV absorbance reductions as high as 49%, mainly due to the presence of metal oxides including Al(2)O(3), Fe(2)O(3) and TiO(2) in the natural pumice, which are known to catalyze the decomposition of peroxide forming strong oxidants. Coating the original pumice particles with iron oxides significantly enhanced the removal of NOM with peroxide. A strong linear correlation was found between iron contents of coated pumices and UV absorbance reductions. Peroxide consumption also correlated with UV absorbance reduction. Control experiments proved the effective coating and the stability of iron oxide species bound on pumice surfaces. Results overall indicated that in addition to adsorptive removal of NOM by metal oxides on pumice surfaces, surface reactions between iron oxides and peroxide result in the formation of strong oxidants, probably like hydroxyl radicals, which further oxidize both adsorbed NOM and remaining NOM in solution, similar to those in Fenton-like reactions.

  15. Evaluation of gravimetric and volumetric dispensers of particles of nuclear material. [Accurate dispensing of fissile and fertile fuel into fuel rods

    SciTech Connect

    Bayne, C.K.; Angelini, P.

    1981-08-01

    Theoretical and experimental studies compared the abilities of volumetric and gravimetric dispensers to dispense accurately fissile and fertile fuel particles. Such devices are being developed for the fabrication of sphere-pac fuel rods for high-temperature gas-cooled light water and fast breeder reactors. The theoretical examination suggests that, although the fuel particles are dispensed more accurately by the gravimetric dispenser, the amount of nuclear material in the fuel particles dispensed by the two methods is not significantly different. The experimental results demonstrated that the volumetric dispenser can dispense both fuel particles and nuclear materials that meet standards for fabricating fuel rods. Performance of the more complex gravimetric dispenser was not significantly better than that of the simple yet accurate volumetric dispenser.

  16. Low loss Sendust powder cores comprised of particles coated by sodium salt insulating layer

    NASA Astrophysics Data System (ADS)

    Wei, Ding; Wang, Xian; Nie, Yan; Feng, Zekun; Gong, Rongzhou; Chen, Yajie; Harris, V. G.

    2015-05-01

    Toroid-shaped Sendust powder cores were prepared from cold pressing mechanically pulverized Fe-Si-Al powder that had been coated using an inorganic insulating layer. The present work focuses on the effect of the sodium salt-coated Sendust particles upon the high frequency magnetic properties. Sendust powders, having a particle size range of ˜125 μm, exhibit a high saturation magnetization of 118.9 A.m2/kg and a low coercivity of 56 A/m. The experiments indicate that the sodium-based glass insulating layer synthesized from sodium metaphosphate and sodium metaborate can effectively reduce the change in permeability with frequency or DC bias field, yielding high effective permeability (μe) of ˜113 over a wide frequency range from 10 kHz-1 MHz. Furthermore, the effective permeability is measured at ˜27 at H = 7854 A/m, indicating stable and high effective permeability under a DC bias field. The measurements of permeability under DC bias field indicate a peak in the quality factor (Q) values corresponding to a DC-bias field of 1.5-6 (kA/m) at frequencies from 50 to 200 kHz: The effective permeability remains at ˜74. The sodium salt-coated granular cores demonstrate a core loss of 68 mW/cm3 at Bm = 50 mT and f = 50 kHz: These values compare favorably to those of silicone coated Sendust particles.

  17. Effective density and morphology of particles emitted from small-scale combustion of various wood fuels.

    PubMed

    Leskinen, Jani; Ihalainen, Mika; Torvela, Tiina; Kortelainen, Miika; Lamberg, Heikki; Tiitta, Petri; Jakobi, Gert; Grigonyte, Julija; Joutsensaari, Jorma; Sippula, Olli; Tissari, Jarkko; Virtanen, Annele; Zimmermann, Ralf; Jokiniemi, Jorma

    2014-11-18

    The effective density of fine particles emitted from small-scale wood combustion of various fuels were determined with a system consisting of an aerosol particle mass analyzer and a scanning mobility particle sizer (APM-SMPS). A novel sampling chamber was combined to the system to enable measurements of highly fluctuating combustion processes. In addition, mass-mobility exponents (relates mass and mobility size) were determined from the density data to describe the shape of the particles. Particle size, type of fuel, combustion phase, and combustion conditions were found to have an effect on the effective density and the particle shape. For example, steady combustion phase produced agglomerates with effective density of roughly 1 g cm(-3) for small particles, decreasing to 0.25 g cm(-3) for 400 nm particles. The effective density was higher for particles emitted from glowing embers phase (ca. 1-2 g cm(-3)), and a clear size dependency was not observed as the particles were nearly spherical in shape. This study shows that a single value cannot be used for the effective density of particles emitted from wood combustion.

  18. Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings

    NASA Astrophysics Data System (ADS)

    Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Zhong, Zhihui; Wang, Li; Li, Hongxia; Xiao, Kai

    2014-10-01

    Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating.

  19. Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings.

    PubMed

    Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Zhong, Zhihui; Wang, Li; Li, Hongxia; Xiao, Kai

    2014-10-24

    Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating.

  20. Effect of Particle Size on the Micro-cracking of Plasma-Sprayed YSZ Coatings During Thermal Cycle Testing

    NASA Astrophysics Data System (ADS)

    Huang, Jibo; Wang, Weize; Yu, Jingye; Wu, Liangmin; Feng, Zhengqu

    2017-04-01

    The failure of plasma-sprayed thermal barrier coatings (TBCs) during service or thermal cycle testing usually results from internal cracking in the top coat, erosion and CMAS (calcium-magnesium-alumina-silicate)-induced damage, etc. The microstructure of ceramic coatings affects their durability and other properties of TBCs. In the present study, yttria-stabilized zirconia (YSZ) coatings were deposited by atmospheric plasma spraying (APS) using feedstocks with different particle sizes. In addition, the effect of particle size on damage evolution in the top coat was investigated. It is found that the coatings deposited using coarse particles show the higher thermal cycle life. Crack length grew with increasing numbers of thermal cycles. The faster crack growth rate can be found for the coatings deposited from fine particles. The porosity of the coating made from the coarse powder is larger than the porosity of the coating made from fine powder both in the as-sprayed condition and after thermal cycling. The changes in crack growth rate and the porosity are related to the effect of sintering and stress evolution in coatings during the thermal cyclic tests.

  1. Effect of Particle Size on the Micro-cracking of Plasma-Sprayed YSZ Coatings During Thermal Cycle Testing

    NASA Astrophysics Data System (ADS)

    Huang, Jibo; Wang, Weize; Yu, Jingye; Wu, Liangmin; Feng, Zhengqu

    2017-03-01

    The failure of plasma-sprayed thermal barrier coatings (TBCs) during service or thermal cycle testing usually results from internal cracking in the top coat, erosion and CMAS (calcium-magnesium-alumina-silicate)-induced damage, etc. The microstructure of ceramic coatings affects their durability and other properties of TBCs. In the present study, yttria-stabilized zirconia (YSZ) coatings were deposited by atmospheric plasma spraying (APS) using feedstocks with different particle sizes. In addition, the effect of particle size on damage evolution in the top coat was investigated. It is found that the coatings deposited using coarse particles show the higher thermal cycle life. Crack length grew with increasing numbers of thermal cycles. The faster crack growth rate can be found for the coatings deposited from fine particles. The porosity of the coating made from the coarse powder is larger than the porosity of the coating made from fine powder both in the as-sprayed condition and after thermal cycling. The changes in crack growth rate and the porosity are related to the effect of sintering and stress evolution in coatings during the thermal cyclic tests.

  2. Mixing fuel particles for space combustion research using acoustics

    NASA Technical Reports Server (NTRS)

    Burns, Robert J.; Johnson, Jerome A.; Klimek, Robert B.

    1988-01-01

    Part of the microgravity science to be conducted aboard the Shuttle (STS) involves combustion using solids, particles, and liquid droplets. The central experimental facts needed for characterization of premixed quiescent particle cloud flames cannot be adequately established by normal gravity studies alone. The experimental results to date of acoustically mixing a prototypical particulate, lycopodium, in a 5 cm diameter by 75 cm long flame tube aboard a Learjet aircraft flying a 20 sec low gravity trajectory are described. Photographic and light detector instrumentation combine to measure and characterize particle cloud uniformity.

  3. Responses of Ammonium Sulfate Particles Coated with Water-Soluble Glutaric Acid to Cyclic Changes in Relative Humidity: Hygroscopicity

    NASA Astrophysics Data System (ADS)

    Chan, M.; Chan, C.

    2006-12-01

    Atmospheric particles, which may have organic coating, exhibit cyclical change in physical state and size in response to ambient relative humidity (RH) change. We measured the hygroscopicity of solid ammonium sulfate (AS) particles initially coated with water-soluble glutaric acid in two consecutive cycles of deliquescence and crystallization utilizing an electrodynamic balance. We also give an analysis on the kinetic and chemical effects of glutaric acid coating on aerosol hygroscopicity. We found that AS particles with glutaric acid coating had different hygroscopicity upon repeated humidification and dehumidification. Once the particles deliquesced, the dissolution of the solid AS core and the glutaric acid coating formed mixed AS/Vglutaric acid solution droplets, which was confirmed by Raman characterization. Glutaric acid coating does not impede the evaporation and condensation rates of water molecules compared to the rates of AS particles. The coating likely affects the aerosol hygroscopicity through dissolution and its interactions with AS. Coating studies with either deliquescence or crystallization measurements, or one complete cycle of these two measurements may not fully assess the effects of the organic coatings on aerosol hygroscopicity.

  4. Formulation of microneedles coated with influenza virus-like particle vaccine.

    PubMed

    Kim, Yeu-Chun; Quan, Fu-Shi; Compans, Richard W; Kang, Sang-Moo; Prausnitz, Mark R

    2010-09-01

    Mortality due to seasonal and pandemic influenza could be reduced by increasing the speed of influenza vaccine production and distribution. We propose that vaccination can be expedited by (1) immunizing with influenza virus-like particle (VLP) vaccines, which are simpler and faster to manufacture than conventional egg-based inactivated virus vaccines, and (2) administering vaccines using microneedle patches, which should simplify vaccine distribution due to their small package size and possible self-administration. In this study, we coated microneedle patches with influenza VLP vaccine, which was released into skin by dissolution within minutes. Optimizing the coating formulation required balancing factors affecting the coating dose and vaccine antigen stability. Vaccine stability, as measured by an in vitro hemagglutination assay, was increased by formulation with increased concentration of trehalose or other stabilizing carbohydrate compounds and decreased concentration of carboxymethylcellulose (CMC) or other viscosity-enhancing compounds. Coating dose was increased by formulation with increased VLP concentration, increased CMC concentration, and decreased trehalose concentration, as well as increased number of dip coating cycles. Finally, vaccination of mice using microneedles stabilized by trehalose generated strong antibody responses and provided full protection against high-dose lethal challenge infection. In summary, this study provides detailed analysis to guide formulation of microneedle patches coated with influenza VLP vaccine and demonstrates effective vaccination in vivo using this system.

  5. Preparation and Micro Mechanical Properties of Nano-Al2O3 Particles Strengthened Ni-based Composite Coatings

    NASA Astrophysics Data System (ADS)

    Wang, Hongmei; Shi, Peijing; Yu, Helong; Xu, Binshi

    Ni-based composite solution containing nano-Al2O3 particles was prepared by high-energy mechanical and chemical processes. The microstructure and nano-particle content of nano-Al2O3/Ni composite coatings were determined by SEM, EDS and TEM. The micro mechanical properties were tested by nano-indentation technique, and the strengthening mechanism was analyzed. The results show that 85 percent of particles in the solution are dispersed in size of nano meter, nano-particles co-deposited in the coating increases by a factor of 53 percent and the structure of the composite coating is more compact and uniform than that of Ni coating. Nano-Al2O3/Ni coatings exhibit excellent micro mechanical properties, the nanohardness and Young's modulus are 7.04 GPa and 225 GPa respectively, which are attributed to finer crystals strengthening, dispersion strengthening and high- density dislocations strengthening.

  6. TiN-based coatings on fuel cladding tubes for advanced nuclear reactors

    SciTech Connect

    Ickchan Kim; Fauzia Khatkhatay; Liang Jiao; Greg Swadener; James Cole; Jian Gan; Haiyan Wang

    2012-10-01

    Titanium nitride (TiN) thin films are coated on HT-9 and MA957 fuel cladding tubes and bars to explore their mechanical strength, thermal stability, diffusion barrier properties, and thermal conductivity properties. The ultimate goal is to implement TiN as an effective diffusion barrier to prevent the inter-diffusion between the nuclear fuel and the cladding material, and thus lead to a longer life time of the cladding tubes. Mechanical tests including hardness and scratch tests for the samples before and after thermal cycle tests show that the films have a high hardness of 28 GPa and excellent adhesion properties despite the thermal treatment. Thermal conductivity measurements demonstrate that the thin TiN films have very minimal impact on the overall thermal conductivity of the MA957 and HT9 substrates, i.e., the thermal conductivity of the uncoated HT-9 and MA957 substrates was 26.25 and 28.44 W m-1K-1 , and that of the coated ones was 26.21 and 28.38 W m-1K-1, respectively. A preliminary Ce diffusion test on the couple of Ce/TiN/HT-9 suggests that TiN has excellent material compatibility and good diffusion barrier properties.

  7. Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

    SciTech Connect

    Schmidt, Andrew J.; Delegard, Calvin H.; Bryan, Samuel A.; Elmore, Monte R.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2003-08-01

    The path forward for managing of Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without K Basin sludge addition. The testing described in this report consisted of 12 tests. In 10 of the tests, 4.3 to 26.4 g of fuel particles of selected size distribution were placed into 60- or 800-ml reaction vessels with 0 to 100 g settled sludge. In another test, a single 3.72-g fuel fragment (i.e., 7150-mm particle) was placed in a 60 ml reaction vessel with no added sludge. The twelfth test contained only sludge. The fuel particles were prepared by crushing archived coupons (samples) from an irradiated metallic uranium fuel element. After loading the sludge materials (whether fuel particles, mixtures of fuel particles and sludge, or sludge-only) into reaction vessels, the solids were covered with an excess of K Basin water, the vessels closed and connected to a gas measurement manifold, and the vessels back-flushed with inert neon cover gas. The vessels were then heated to a constant temperature. The gas pressures and temperatures were monitored continuously from the times the vessels were purged. Gas samples were collected at various times during the tests, and the samples analyzed by mass spectrometry. Data on the reaction rates of uranium metal fuel particles with water as a function of temperature and particle size were generated. The data were compared with published studies on metallic uranium corrosion kinetics. The effects of an intimate overlying sludge layer

  8. Simultaneous amplitude and phase contrast imaging of burning fuel particle and flame with digital inline holography: Model and verification

    NASA Astrophysics Data System (ADS)

    Wu, Yingchun; Brunel, Marc; Li, Renxian; Lan, Lijuan; Ao, Wen; Chen, Jia; Wu, Xuecheng; Gréhan, Gérard

    2017-09-01

    Three-dimensional (3D) quantitative measurements of reacting multiphase micro-objects are of great interest in fuel particle combustion, which is composed of an inner fuel particle and an outer gas flame. Three models of digital inline holography of this composite fuel particle in the framework of light scattering and diffraction theories have been proposed, and then verified with reported experimental observations. Results show that the dispersed fuel particle and the gas flame distinguish in the reconstructed amplitude and phase contrast images, and reveal that the low extinction efficiency and phase shifting of the highly transparent, weakly scattering gas flame accounts for the difference.

  9. Effects on Fuel Consumption and Diesel Engine Deposits from Nano-Particle Oil Additive

    DTIC Science & Technology

    2010-07-01

    Products HTBCT High Temperature Benchtop Corrosion Test HwFET Highway Fuel Economy Test IF Inorganic Fullerene JP-8 A kerosene based jet fuel lbs...engine crankcase lubricants at the request of TARDEC. This additive contains inorganic fullerene -like (IF) nano- particles of WS2 which were claimed...volume and hardness change are shown in Table 4 with MIL-PRF-46167D specified limits. Table 4: Seal Compatibility Test Results Material Property

  10. Photothermal cancer therapy using graphitic carbon–coated magnetic particles prepared by one-pot synthesis

    PubMed Central

    Lee, Hyo-Jeong; Sanetuntikul, Jakkid; Choi, Eun-Sook; Lee, Bo Ram; Kim, Jung-Hee; Kim, Eunjoo; Shanmugam, Sangaraju

    2015-01-01

    We describe here a simple synthetic strategy for the fabrication of carbon-coated Fe3O4 (Fe3O4@C) particles using a single-component precursor, iron (III) diethylenetriaminepentaacetic acid complex. Physicochemical analyses revealed that the core of the synthesized particles consists of ferromagnetic Fe3O4 material ranging several hundred nanometers, embedded in nitrogen-doped graphitic carbon with a thickness of ~120 nm. Because of their photothermal activity (absorption of near-infrared [NIR] light), the Fe3O4@C particles have been investigated for photothermal therapeutic applications. An example of one such application would be the use of Fe3O4@C particles in human adenocarcinoma A549 cells by means of NIR-triggered cell death. In this system, the Fe3O4@C can rapidly generate heat, causing >98% cell death within 10 minutes under 808 nm NIR laser irradiation (2.3 W cm−2). These Fe3O4@C particles provided a superior photothermal therapeutic effect by intratumoral delivery and NIR irradiation of tumor xenografts. These results demonstrate that one-pot synthesis of carbon-coated magnetic particles could provide promising materials for future clinical applications and encourage further investigation of this simple method. PMID:25565819

  11. Polydopamine-Coated Magnetic Composite Particles with an Enhanced Photothermal Effect.

    PubMed

    Zheng, Rui; Wang, Sheng; Tian, Ye; Jiang, Xinguo; Fu, Deliang; Shen, Shun; Yang, Wuli

    2015-07-29

    Recently, photothermal therapy (PTT) that utilizes photothermal conversion (PTC) agents to ablate cancer under near-infrared (NIR) irradiation has attracted a growing amount of attention because of its excellent therapeutic efficacy and improved target selectivity. Therefore, exploring novel PTC agents with an outstanding photothermal effect is a current research focus. Herein, we reported a polydopamine-coated magnetic composite particle with an enhanced PTC effect, which was synthesized simply through coating polydopamine (PDA) on the surface of magnetic Fe3O4 particles. Compared with magnetic Fe3O4 particles and PDA nanospheres, the core-shell nanomaterials exhibited an increased NIR absorption, and thus, an enhanced photothermal effect was obtained. We demonstrated the in vitro and in vivo effects of the photothermal therapy using our composite particles and their ability as a contrast agent in the T2-weighted magnetic resonance imaging. These results indicated that the multifunctional composite particles with enhanced photothermal effect are superior to magnetic Fe3O4 particles and PDA nanospheres alone.

  12. Ice Nucleation of Bare and Sulfuric Acid-coated Mineral Dust Particles and Implication for Cloud Properties

    SciTech Connect

    Kulkarni, Gourihar R.; Sanders, Cassandra N.; Zhang, Kai; Liu, Xiaohong; Zhao, Chun

    2014-08-27

    Ice nucleation properties of different dust species coated with soluble material are not well understood. We determined the ice nucleation ability of bare and sulfuric acid coated mineral dust particles as a function of temperature (-25 to -35 deg C) and relative humidity with respect to water (RHw). Five different mineral dust species: Arizona test dust (ATD), illite, montmorillonite, quartz and kaolinite were dry dispersed and size-selected at 150 nm and exposed to sulfuric acid vapors in the coating apparatus. The condensed sulfuric acid soluble mass fraction per particle was estimated from the cloud condensation nuclei activated fraction measurements. The fraction of dust particles nucleating ice at various temperatures and RHw was determined using a compact ice chamber. In water-subsaturated conditions, compared to bare dust particles, we found that only coated ATD particles showed suppression of ice nucleation ability while other four dust species did not showed the effect of coating on the fraction of particles nucleating ice. The results suggest that interactions between the dust surface and sulfuric acid vapor are important, such that interactions may or may not modify the surface via chemical reactions with sulfuric acid. At water-supersaturated conditions we did not observed the effect of coating, i.e. the bare and coated dust particles had similar ice nucleation behavior.

  13. Mechanical reliability and life prediction of coated metallic interconnects within solid oxide fuel cells

    DOE PAGES

    Xu, Zhijie; Xu, Wei; Stephens, Elizabeth; ...

    2017-07-03

    Metallic cell interconnects (IC) made of ferritic stainless steels, i.e., iron-based alloys, have been increasingly favored in the recent development of planar solid oxide fuel cells (SOFCs) because of their advantages in excellent imperviousness, low electrical resistance, ease in fabrication, and cost effectiveness. Typical SOFC operating conditions inevitably lead to the formation of oxide scales on the surface of ferritic stainless steel, which could cause delamination, buckling, and spallation resulting from the mismatch of the coefficient of thermal expansion and eventually reduce the lifetime of the interconnect components. Various protective coating techniques have been applied to alleviate these drawbacks. Inmore » the present work, a fracture-mechanics-based quantitative modeling framework has been established to predict the mechanical reliability and lifetime of the spinel-coated, surface-modified specimens under an isothermal cooling cycle. Analytical solutions have been formulated to evaluate the scale/substrate interfacial strength and determine the critical oxide thickness in terms of a variety of design factors, such as coating thickness, material properties, and uncertainties. In conclusion, the findings then are correlated with the experimentally measured oxide scale growth kinetics to quantify the predicted lifetime of the metallic interconnects.« less

  14. Stratospheric Injection of Reflective Aerosols or Particles by Means of Aviation Fuel Additives.

    NASA Astrophysics Data System (ADS)

    Gorman, J.

    2007-12-01

    Various suggestions have been made for stratospheric aerosols or particles to simulate the observed cooling effect of major volcanic eruptions. The best known is the detailed proposal of Paul Crutzen for sulphur dioxide. Also extensively discussed is diatomous earth, injected as individual diatoms. (Silica particles originating as marine shells.) This paper describes the selection and preliminary testing of chemicals that might be used as aviation fuel additives to distribute these two products, sulphur dioxide and micron sized silica particles, from a high flying commercial or military aircraft. The two chemicals tested are dimethyl sulphide to produce sulphur dioxide and tetra ethyl silicate to produce silica particles. In a closed glass jar both of these chemicals are indistinguishable from jet aviation fuel. Both are clear, colourless, oily liquids. Both dissolve in aviation fuel in any proportion. Solutions of each of these chemicals have been burned in a paraffin blowlamp as a simple simulation of a jet engine combustion chamber. Observation of the combustion suggests that the desired chemicals are produced and that the silica particles are of smoke or mist (micron) size. It is suggested that the solutions would probably have no detrimental effects on the fuel tanks, pipes, pumps or combustion chambers of the jet engine. This paper includes general facts about jet engines, aviation fuel, aircraft fuel systems and flight plans which may not be known to climate scientists. Also briefly considered are the health consequences of silica particles in the stratosphere. No tests have been done on a jet engine. Suggestions are made on the type of tests that would be needed by an organization having engine static test facilities.

  15. Particle morphology dependent superhydrophobicity in treated diatomaceous earth/polystyrene coatings

    NASA Astrophysics Data System (ADS)

    Sedai, Bhishma R.; Alavi, S. Habib; Harimkar, Sandip P.; McCollum, Mark; Donoghue, Joseph F.; Blum, Frank D.

    2017-09-01

    Superhydrophobic surfaces have been prepared from three different types of diatomaceous earth (DE) particles treated with 3-(heptafluoroisopropoxy)propyltrimethoxysilane (HFIP-TMS) and low molecular mass polystyrene. The untreated particles, consisting of CelTix DE (disk shape), DiaFil DE (rod shape) and EcoFlat DE (irregular), were studied using particle size analysis, bulk density, pore volume and surface area analysis (via Brunauer-Emmett-Teller, BET, methods). The treated particles were characterized with thermogravimetric analysis (TGA), contact angles, scanning electron microscopy, profilometry, and FTIR spectroscopy. The minimum amount of silane coupling agent on the DE surfaces required to obtain superhydrophobicity of the particles was determined and found to be dependent on the particle morphology. In the coatings made from different particles with 2.4 wt% HFIP-TMS, the minimum amounts of treated particles (loadings) for superhydrophobicity was determined with the less dense CelTix DE requiring about 30 wt%, DiaFil DE requiring about 40 wt%, and EcoFlat DE each requiring about 60 wt% loading of treated particles.

  16. Application of gelatin-coated magnetic particles for isolation of genomic DNA from bacterial cells.

    PubMed

    Intorasoot, Sorasak; Srirung, Rujira; Intorasoot, Amornrat; Ngamratanapaiboon, Surachai

    2009-03-15

    Gelatin-coated magnetic particles were implemented for bacterial genomic DNA isolation in this study. Based on structural differences in the cell wall, the standard strains Staphylococcus aureus and Escherichia coli were selected. The quantity, quality, and timing process for DNA extraction using gelatin-coated magnetite were compared to reference phenol-chloroform extraction and a commercially available kit. Approximately twice as much DNA was recovered with the use of coated magnetite, providing greater yields than other DNA extraction methods. In addition, the DNA quality was determined using 16S ribosomal DNA (rDNA) gene amplification by polymerase chain reaction (PCR). The described technique is rapid, simple, and a well-suited method to use with PCR for diagnosis of bacterial infections.

  17. Nano-magnetic particles used in biomedicine: core and coating materials.

    PubMed

    Karimi, Z; Karimi, L; Shokrollahi, H

    2013-07-01

    Magnetic nanoparticles for medical applications have been developed by many researchers. Separation, immunoassay, drug delivery, magnetic resonance imaging and hyperthermia are enhanced by the use of suitable magnetic nanoparticles and coating materials in the form of ferrofluids. Due to their low biocompatibility and low dispersion in water solutions, nanoparticles that are used for biomedical applications require surface treatment. Various kinds of coating materials including organic materials (polymers), inorganic metals (gold, platinum) or metal oxides (aluminum oxide, cobalt oxide) have been attracted during the last few years. Based on the recent advances and the importance of nanomedicine in human life, this paper attempts to give a brief summary on the different ferrite nano-magnetic particles and coatings used in nanomedicine.

  18. A comparative study of the number and mass of fine particles emitted with diesel fuel and marine gas oil (MGO)

    NASA Astrophysics Data System (ADS)

    Nabi, Md. Nurun; Brown, Richard J.; Ristovski, Zoran; Hustad, Johan Einar

    2012-09-01

    The current investigation reports on diesel particulate matter emissions, with special interest in fine particles from the combustion of two base fuels. The base fuels selected were diesel fuel and marine gas oil (MGO). The experiments were conducted with a four-stroke, six-cylinder, direct injection diesel engine. The results showed that the fine particle number emissions measured by both SMPS and ELPI were higher with MGO compared to diesel fuel. It was observed that the fine particle number emissions with the two base fuels were quantitatively different but qualitatively similar. The gravimetric (mass basis) measurement also showed higher total particulate matter (TPM) emissions with the MGO. The smoke emissions, which were part of TPM, were also higher for the MGO. No significant changes in the mass flow rate of fuel and the brake-specific fuel consumption (BSFC) were observed between the two base fuels.

  19. A novel inversion method to calculate the mass fraction of coated refractory black carbon using a centrifugal particle mass analyzer and single particle soot photometer

    NASA Astrophysics Data System (ADS)

    Irwin, M.; Broda, K.; Olfert, J. S.; Schill, G. P.; McMeeking, G. R.; Schnitzler, E.; Jäger, W.

    2016-12-01

    Refractory black carbon (rBC) has important atmospheric impacts due to its ability to absorb light, and its interactions with light are partly governed by the acquisition of coatings or other mixing processes. Here, a novel inversion method is presented which derives the mass fraction of coated rBC using a coupled centrifugal particle mass analyzer (CPMA) and single particle soot photometer (SP2). The CPMA selects particles of a known mass-­to-­charge ratio, and the SP2 detects the mass of rBC in each individual particle. The results of the inversion are the simultaneous number distributions of both rBC mass and total particle mass. Practically, the distribution can be integrated to find properties of the total aerosol population, for example, i) mass fraction of coating and ii) mass of coating on a particle of known total mass. This was demonstrated via smog chamber experiments. Initially, particles in the chamber were pure rBC, produced from a methane burner and passed through a diffusion dryer and thermal denuder. An organic (non-rBC) coating was then grown onto the aerosol over several hours via photooxidation with p-xylene. The CPMA-SP2 coupled system sampled the aerosol over the reaction period as the coating grew. The CPMA was sequentially stepped over a mass range from 0.3 to 28 fg and the SP2 measured the mass of rBC in each individual CPMA-classified particle. The number and mass distributions were constructed using the inversion. As expected, the mass and number distributions of rBC and total mass were equivalent for uncoated particles. As the non-rBC coating thickness increased over time, a shift in the number distribution towards higher total mass was observed. At the end of the experiment, fresh rBC (i.e. uncoated, bare particles) was injected into the chamber, creating an external mixture of coated and uncoated particles. This external mixture was clearly resolved in the number distribution of rBC and total particle mass. It is expected that the

  20. Selective catalytic reduction operation with heavy fuel oil: NOx, NH3, and particle emissions.

    PubMed

    Lehtoranta, Kati; Vesala, Hannu; Koponen, Päivi; Korhonen, Satu

    2015-04-07

    To meet stringent NOx emission limits, selective catalytic reduction (SCR) is increasingly utilized in ships, likely also in combination with low-priced higher sulfur level fuels. In this study, the performance of SCR was studied by utilizing NOx, NH3, and particle measurements. Urea decomposition was studied with ammonia and isocyanic acid measurements and was found to be more effective with heavy fuel oil (HFO) than with light fuel oil. This is suggested to be explained by the metals found in HFO contributing to metal oxide particles catalyzing the hydrolysis reaction prior to SCR. At the exhaust temperature of 340 °C NOx reduction was 85-90%, while at lower temperatures the efficiency decreased. By increasing the catalyst loading, the low temperature behavior of the SCR was enhanced. The drawback of this, however, was the tendency of particle emissions (sulfate) to increase at higher temperatures with higher loaded catalysts. The particle size distribution results showed high amounts of nanoparticles (in 25-30 nm size), the formation of which SCR either increased or decreased. The findings of this work provide a better understanding of the usage of SCR in combination with a higher sulfur level fuel and also of ship particle emissions, which are a growing concern.

  1. Chemical compositions of black carbon particle cores and coatings via soot particle aerosol mass spectrometry with photoionization and electron ionization.

    PubMed

    Canagaratna, Manjula R; Massoli, Paola; Browne, Eleanor C; Franklin, Jonathan P; Wilson, Kevin R; Onasch, Timothy B; Kirchstetter, Thomas W; Fortner, Edward C; Kolb, Charles E; Jayne, John T; Kroll, Jesse H; Worsnop, Douglas R

    2015-05-14

    Black carbon is an important constituent of atmospheric aerosol particle matter (PM) with significant effects on the global radiation budget and on human health. The soot particle aerosol mass spectrometer (SP-AMS) has been developed and deployed for real-time ambient measurements of refractory carbon particles. In the SP-AMS, black carbon or metallic particles are vaporized through absorption of 1064 nm light from a CW Nd:YAG laser. This scheme allows for continuous "soft" vaporization of both core and coating materials. The main focus of this work is to characterize the extent to which this vaporization scheme provides enhanced chemical composition information about aerosol particles. This information is difficult to extract from standard SP-AMS mass spectra because they are complicated by extensive fragmentation from the harsh 70 eV EI ionization scheme that is typically used in these instruments. Thus, in this work synchotron-generated vacuum ultraviolet (VUV) light in the 8-14 eV range is used to measure VUV-SP-AMS spectra with minimal fragmentation. VUV-SP-AMS spectra of commercially available carbon black, fullerene black, and laboratory generated flame soots were obtained. Small carbon cluster cations (C(+)-C5(+)) were found to dominate the VUV-SP-AMS spectra of all the samples, indicating that the corresponding neutral clusters are key products of the SP vaporization process. Intercomparisons of carbon cluster ratios observed in VUV-SP-AMS and SP-AMS spectra are used to confirm spectral features that could be used to distinguish between different types of refractory carbon particles. VUV-SP-AMS spectra of oxidized organic species adsorbed on absorbing cores are also examined and found to display less thermally induced decomposition and fragmentation than spectra obtained with thermal vaporization at 200 °C (the minimum temperature needed to quantitatively vaporize ambient oxidized organic aerosol with a continuously heated surface). The particle cores

  2. Performance impact of dynamic surface coatings on polymeric insulator-based dielectrophoretic particle separators.

    PubMed

    Davalos, Rafael V; McGraw, Gregory J; Wallow, Thomas I; Morales, Alfredo M; Krafcik, Karen L; Fintschenko, Yolanda; Cummings, Eric B; Simmons, Blake A

    2008-02-01

    Efficient and robust particle separation and enrichment techniques are critical for a diverse range of lab-on-a-chip analytical devices including pathogen detection, sample preparation, high-throughput particle sorting, and biomedical diagnostics. Previously, using insulator-based dielectrophoresis (iDEP) in microfluidic glass devices, we demonstrated simultaneous particle separation and concentration of various biological organisms, polymer microbeads, and viruses. As an alternative to glass, we evaluate the performance of similar iDEP structures produced in polymer-based microfluidic devices. There are numerous processing and operational advantages that motivate our transition to polymers such as the availability of numerous innate chemical compositions for tailoring performance, mechanical robustness, economy of scale, and ease of thermoforming and mass manufacturing. The polymer chips we have evaluated are fabricated through an injection molding process of the commercially available cyclic olefin copolymer Zeonor 1060R. This publication is the first to demonstrate insulator-based dielectrophoretic biological particle differentiation in a polymeric device injection molded from a silicon master. The results demonstrate that the polymer devices achieve the same performance metrics as glass devices. We also demonstrate an effective means of enhancing performance of these microsystems in terms of system power demand through the use of a dynamic surface coating. We demonstrate that the commercially available nonionic block copolymer surfactant, Pluronic F127, has a strong interaction with the cyclic olefin copolymer at very low concentrations, positively impacting performance by decreasing the electric field necessary to achieve particle trapping by an order of magnitude. The presence of this dynamic surface coating, therefore, lowers the power required to operate such devices and minimizes Joule heating. The results of this study demonstrate that iDEP polymeric

  3. Stability of EUV multilayer coatings to low energy alpha particles bombardment.

    PubMed

    Nardello, M; Zuppella, Paola; Polito, V; Corso, Alain Jody; Zuccon, Sara; Pelizzo, M G

    2013-11-18

    Future solar missions will investigate the Sun from very close distances and optical components are constantly exposed to low energy ions irradiation. In this work we present the results of a new experiment related to low energy alpha particles bombardments on Mo/Si multilayer optical coatings. Different multilayer samples, with and without a protecting capping layer, have been exposed to low energy alpha particles (4keV), fixing the ions fluency and varying the time of exposure in order to change the total dose accumulated. The experimental parameters have been selected considering the potential application of the coatings to future solar missions. Results show that the physical processes occurred at the uppermost interfaces can strongly damage the structure.

  4. Particle Size Influences on the Coating Microstructure through Green Chromia Inclusion in Plasma Electrolytic Oxidation.

    PubMed

    Liu, Chen-Yu; Tsai, Dah-Shyang; Wang, Jian-Mao; Tsai, James T J; Chou, Chen-Chia

    2017-07-05

    In an effort to color the aluminum alloy surface green via plasma electrolytic oxidation (PEO), two alkaline solutions have been employed with particulate inclusions and sodium aluminate. Electrolyte I comprises a self-made chromia pigment with a mean particle size 69 nm, whereas electrolyte II contains a commercially available pigment, GN-M, with a larger particle size 351 nm. Both pigments are oxygen deficient Cr2O3-δ of corundum-type structure before coating, the oxidative environment of PEO converts them into stoichiometric Cr2O3. In electrolyte I and II, the oxides of chromium and aluminum deposit simultaneously under analogous PEO conditions, yet resulting in very different microstructures. The GN-M inclusion of large size amasses on top of the coating, while the self-made inclusion goes deep, and closely associates with alumina and pores. The oxide coating, grown in electrolyte II, consists of a top Cr2O3-rich layer and a dense alumina layer underneath, delineated by the boundary marked with microdischarge burns. On the other hand, the self-made particulate inclusion appears to bring the electric microdischarges inside the coating and create inner pores and damages. The structure difference, caused by the difference in microdischarge locations, is attributed to shifting of the Cr2O3-Al2O3 interface where p-type and n-type semiconductors meet.

  5. Differential proteomic analysis of mouse macrophages exposed to adsorbate-loaded heavy fuel oil derived combustion particles using an automated sample-preparation workflow.

    PubMed

    Kanashova, Tamara; Popp, Oliver; Orasche, Jürgen; Karg, Erwin; Harndorf, Horst; Stengel, Benjamin; Sklorz, Martin; Streibel, Thorsten; Zimmermann, Ralf; Dittmar, Gunnar

    2015-08-01

    Ship diesel combustion particles are known to cause broad cytotoxic effects and thereby strongly impact human health. Particles from heavy fuel oil (HFO) operated ships are considered as particularly dangerous. However, little is known about the relevant components of the ship emission particles. In particular, it is interesting to know if the particle cores, consisting of soot and metal oxides, or the adsorbate layers, consisting of semi- and low-volatile organic compounds and salts, are more relevant. We therefore sought to relate the adsorbates and the core composition of HFO combustion particles to the early cellular responses, allowing for the development of measures that counteract their detrimental effects. Hence, the semi-volatile coating of HFO-operated ship diesel engine particles was removed by stepwise thermal stripping using different temperatures. RAW 264.7 macrophages were exposed to native and thermally stripped particles in submersed culture. Proteomic changes were monitored by two different quantitative mass spectrometry approaches, stable isotope labeling by amino acids in cell culture (SILAC) and dimethyl labeling. Our data revealed that cells reacted differently to native or stripped HFO combustion particles. Cells exposed to thermally stripped particles showed a very differential reaction with respect to the composition of the individual chemical load of the particle. The cellular reactions of the HFO particles included reaction to oxidative stress, reorganization of the cytoskeleton and changes in endocytosis. Cells exposed to the 280 °C treated particles showed an induction of RNA-related processes, a number of mitochondria-associated processes as well as DNA damage response, while the exposure to 580 °C treated HFO particles mainly induced the regulation of intracellular transport. In summary, our analysis based on a highly reproducible automated proteomic sample-preparation procedure shows a diverse cellular response, depending on the

  6. Nanostructure of Metallic Particles in Light Water Reactor Used Nuclear Fuel

    SciTech Connect

    Buck, Edgar C.; Mausolf, Edward J.; Mcnamara, Bruce K.; Soderquist, Chuck Z.; Schwantes, Jon M.

    2015-03-11

    The extraordinary nano-structure of metallic particles in light water reactor fuels points to possible high reactivity through increased surface area and a high concentration of high energy defect sites. We have analyzed the metallic epsilon particles from a high burn-up fuel from a boiling water reactor using transmission electron microscopy and have observed a much finer nanostructure in these particles than has been reported previously. The individual round particles that varying in size between ~20 and ~50 nm appear to consist of individual crystallites on the order of 2-3 nm in diameter. It is likely that in-reactor irradiation induce displacement cascades results in the formation of the nano-structure. The composition of these metallic phases is variable yet the structure of the material is consistent with the hexagonal close packed structure of epsilon-ruthenium. These findings suggest that unusual catalytic behavior of these materials might be expected, particularly under accident conditions.

  7. [Implantation of collagen coated hydroxyapatite particles. A clinical-histological study in humans].

    PubMed

    Sanz, M; Bascones, A; Kessler, A; García Nuñez, J; Newman, M G; Robertson, M A; Carranza, F A

    1989-05-01

    In this study, histologic behaviour of collagen coated hydroxylapatite particles implanted in human periodontal osseous defects has been analyzed. This material was surgically implanted in four patients, and reentry and block biopsies were carried out 4 and 6 months later. The histologic results demonstrate that this material is well tolerated by surrounding tissues, not eliciting an inflammatory reaction. At four months, the hydroxylapatite particles appear encapsulated by a very cellular connective tissue and at 6 months are found in direct contact with osteoid and mature bone. This material acts as a filler material, being fully biocompatible and stimulating an osseoconductive reaction of the adjacent alveolar bone.

  8. Preparation of nanosized drug particles by the coating of inorganic cores: naproxen and ketoprofen on alumina.

    PubMed

    Joguet, Laurent; Sondi, Ivan; Matijević, Egon

    2002-07-15

    Nanosized alumina particles with modal diameters of 8 and 13 nm, respectively, were successfully coated by the adsorption of naproxen [(+)-6-methoxy-alpha-methyl-2-naphthalene acetic acid] and ketoprofen [alpha-methyl-3-(4-methylbenzoil) benzene acetic acid] in aqueous and ethanol solutions. The presence of the drugs at the alumina surface was confirmed by attenuated total reflection infrared spectroscopy and electrokinetic measurements, while their bound amounts were assessed by thermogravimetric analysis.

  9. Using CrAIN Multilayer Coatings to Improve Oxidation Resistance of Steel Interconnects for Solid Oxide Fuel Cell Stacks

    SciTech Connect

    Smith, Richard J.; Tripp, C.; Knospe, Anders; Ramana, C. V.; Gorokhovsky, Vladimir I.; Shutthanandan, V.; Gelles, David S.

    2004-06-01

    The requirements of low cost and high-tempurature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigatedt he performance of steel plates with multilayer coatings consisting of CrN for electrical conductivity and CrAIN for oxidation resistance. The coatings were deposited usin large area filterd arc deposition technolgy, and subsequently annealed in air for up to 25 hours at 800 degrees celsius. The composition, structer and morphology of the coated plates were characterized using RBS, nuclear reaction analysis, AFM and TEM techniques. By altering the architecture of the layers within the coatings, the rate of oxidation was reduced by more than an order of magnitute. Electrical resistance was measured at room temperature.

  10. Effects of Alternative Fuels and Aromatics on Gas-Turbine Particle Emissions

    NASA Astrophysics Data System (ADS)

    Thornhill, K. L., II; Moore, R.; Winstead, E.; Anderson, B. E.; Klettlinger, J. L.; Ross, R. C.; Surgenor, A.

    2015-12-01

    This presentation describes experiments conducted with a Honeywell GTCP36-150 Auxiliary Power Unit (APU) to evaluate the effects of varying fuel composition on particle emissions. The APU uses a single-stage compressor stage, gas turbine engine with a can-type combustor to generate bypass flow and electrical power for supporting small aircraft and helicopters. It is installed in a "hush-house" at NASA Glenn Research Center and is configured as a stand-alone unit that can be fueled from an onboard tank or external supply. It operates at constant RPM, but its fuel flow can be varied by changing the electrical load or volume of bypass flow. For these tests, an external bank of resistors were attached to the APU's DC and AC electrical outlets and emissions measurements were made at low, medium and maximum electrical current loads. Exhaust samples were drawn from several points downstream in the exhaust duct and fed to an extensive suite of gas and aerosol sensors installed within a mobile laboratory parked nearby. Aromatic- and sulfur-free synthetic kerosenes from Rentech, Gevo, UOP, Amyris and Sasol were tested and their potential to reduce PM emissions evaluated against a single Jet A1 base fuel. The role of aromatic compounds in regulating soot emissions was also evaluated by adding metered amounts of aromatic blends (Aro-100, AF-Blend, SAK) and pure compounds (tetracontane and 1-methylnaphthalene) to a base alternative fuel (Sasol). Results show that, relative to Jet A1, alternative fuels reduce nonvolatile particle number emissions by 50-80% and--by virtue of producing much smaller particles—mass emissions by 65-90%; fuels with the highest hydrogen content produced the greatest reductions. Nonvolatile particle emissions varied in proportion to fuel aromatic content, with additives containing the most complex ring structures producing the greatest emission enhancements.

  11. Kaolinite particles as ice nuclei: learning from the use of different types of kaolinite and different coatings

    NASA Astrophysics Data System (ADS)

    Wex, H.; DeMott, P. J.; Tobo, Y.; Hartmann, S.; Rösch, M.; Clauss, T.; Tomsche, L.; Niedermeier, D.; Stratmann, F.

    2013-11-01

    Kaolinite particles from two different sources (Fluka and Clay Minerals Society (CMS)) were examined with respect to their ability to act as ice nuclei. This was done in the water subsaturated regime where often deposition ice nucleation is assumed to occur, and for water supersaturated conditions, i.e. in the immersion freezing mode. Measurements were done using a flow tube (LACIS) and a continuous flow diffusion chamber (CFDC). Pure and coated particles were used, with coating thicknesses of a few nanometer or less, where the coating consisted of either levoglucosan, succinic acid, or sulfuric acid. In general, it was found that the coatings strongly reduced deposition ice nucleation. Remaining ice formation in the water subsaturated regime could be attributed to immersion freezing, with particles immersed in concentrated solutions formed by the coatings. In the immersion freezing mode, ice nucleation rate coefficients, jhet, from both instruments agreed with each other when the residence times in the instruments were accounted for. Fluka kaolinite particles coated with either levoglucosan or succinic acid showed the same IN activity as pure Fluka kaolinite particles, i.e. it can be assumed that these two types of coating did not alter the ice active surface chemically, and that the coatings were diluted enough in the droplets that were formed prior to the ice nucleation, so that freezing point depression was negligible. However, Fluka kaolinite particles which were coated with either pure sulfuric acid or which were first coated with the acid and then exposed to additional water vapor both showed a reduced ability to nucleate ice, compared to the pure particles. For the CMS kaolinite particles, the ability to nucleate ice in the immersion freezing mode was similar for all examined particles, i.e. for the pure ones and the ones with the different types of coating. Moreover, jhet derived for the CMS kaolinite particles was comparable to jhet derived for kaolinite

  12. Fine Particle Emissions from Residual Fuel Oil Combustion: Characterization and Mechanisms of Formation

    DTIC Science & Technology

    2000-08-04

    NC, 1999. 3 . Bachmann, J. D ., Damberg, R. J., Caldwell, J. C., Ed- wards, C., and Koman, P. D ., Review of the National Ambient Air Quality Standards...residual fuel oil combustion to be suspect, as far as emission of toxic fine particles is concerned. Build- ing upon previous work examining the...control number. 1. REPORT DATE 04 AUG 2000 2. REPORT TYPE N/A 3 . DATES COVERED - 4. TITLE AND SUBTITLE Fine Particle Emissions from Residual

  13. Polyethyleneimine coating of magnetic particles increased the stability of an immobilized diglycosidase.

    PubMed

    Minig, Marisol; Mazzaferro, Laura S; Capecce, Agostina; Breccia, Javier D

    2015-01-01

    The diglycosidase, α-rhamnosyl-β-glucosidase, from Acremonium sp. DSM24697 was immobilized by adsorption and cross-linking onto polyaniline-iron (PI) particles. The immobilization yield and the immobilization efficiency were relatively high, 31.2% and 8.9%, respectively. However, the heterogeneous preparation showed lower stability in comparison with the soluble form of the enzyme in operational conditions at 60 °C. One parameter involved in the reduced stability of the heterogeneous preparation was the protein metal-catalyzed oxidation achieved by iron traces supplied from the support. To overcome the harmful effect, iron particles were coated with polyethyleneimine (PEI; 0.84 mg/g) previously for the immobilization of the catalyst. The increased stability of the catalyst was correlated with the amount of iron released from the support. Under operational conditions, the uncoated particles lost between 76% and 52% activity after two cycles of reuse, whereas the PEI-coated preparation reduced 45-28% activity after five cycles of reuse in the range of pH 5.0-10, respectively. Hence, polymer coating of magnetic materials used as enzyme supports might be an interesting approach to improve the performance of biotransformation processes.

  14. Development of Thermal Spraying and Coating Techniques by Using Thixotropic Slurries Including Metals and Ceramics Particles

    NASA Astrophysics Data System (ADS)

    Kirihara, S.; Itakura, Y.; Tasaki, S.

    2013-03-01

    Thermal nanoparticles coating and microlines patterning were newly developed as novel technologies to fabricate fine ceramics layers and geometrical intermetallics patterns for mechanical properties modulations of practical alloys substrates. Nanometer sized alumina particles were dispersed into acrylic liquid resins, and the obtained slurries were sputtered by using compressed air jet. The slurry mists could blow into the arc plasma with argon gas spraying. On stainless steels substrates, the fine surface layers with high wear resistance were formed. In cross sectional microstructures of the coated layers, micromater sized cracks or pores were not observed. Subsequently, pure aluminum particles were dispersed into photo solidified acrylic resins, and the slurry was spread on the stainless steel substrates by using a mechanical knife blade. On the substrates, microline patterns with self similar fractal structures were drawn and fixed by using scanning of an ultra violet laser beam. The patterned pure metal particles were heated by the argon arc plasma spray assisting, and the intermetallics or alloys phases with high hardness were created through reaction diffusions. Microstructures in the coated layers and the patterned lines were observed by using a scanning electron microscopy.

  15. Effects of Compression and Filler Particle Coating on the Electrical Conductivity of Thermoplastic Elastomer Composites

    NASA Astrophysics Data System (ADS)

    Albers, Willem M.; Karttunen, Mikko; Wikström, Lisa; Vilkman, Taisto

    2013-10-01

    Elastomeric polymers can be filled with metallic micro- or nanoparticles to obtain electrical conductivity, in which the conductivity is largely determined by the intrinsic conductivity of and contact resistance between the particles. Electrons will flow through the material effectively when the percolation threshold for near-neighbor contacts is exceeded and sufficiently close contacts between the filler particles are realized for electron tunneling to occur. Silver-coated glass microparticles of two types (fibers and spheres) were used as fillers in a thermoplastic elastomer composite based on styrene-ethylene-butylene-styrene copolymer, and the direct-current (DC) resistance and radiofrequency impedance were significantly reduced by coating the filler particles with octadecylmercaptan. Not only was the resistance reduced but also the atypical positive piezoresistivity effect observed in these elastomers was strongly reduced, such that resistivity values below 0.01 Ω cm were obtained for compression ratios up to 20%. In the DC measurements, an additional decrease of resistivity was obtained by inclusion of π-extended aromatic compounds, such as diphenylhexatriene. Some qualitative theories are presented to illuminate the possible mechanisms of action of these surface coatings on the piezoresistivity.

  16. Organic grain coatings in primitive interplanetary dust particles: Implications for grain sticking in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Flynn, George J.; Wirick, Sue; Keller, Lindsay P.

    2013-10-01

    The chondritic porous interplanetary dust particles (CP IDPs), fragments of asteroids and comets collected by NASA high-altitude research aircraft from the Earth's stratosphere, are recognized as the least altered samples of the original dust of the Solar Nebula available for laboratory examination. We performed high-resolution, ~25 nm/pixel, x-ray imaging and spectroscopy on ultramicrotome sections of CP IDPs, which are aggregates of >104 grains, and identified and characterized ~100 nm thick coatings of organic matter on the surfaces of the individual grains. We estimated the minimum tensile strength of this organic glue to be ~150 to 325 N/m2, comparable to the strength of the weakest cometary meteors, based on the observation that the individual grains of ~5 μm diameter aggregate CP IDPs are not ejected from the particle by electrostatic repulsion due to charging of these IDPs to 10 to 15 volts at 1 A.U. in space. Since organic coatings can increase the sticking coefficient over that of bare mineral grains, these organic grain coatings are likely to have been a significant aid in grain sticking in the Solar Nebula, allowing the first dust particles to aggregate over a much wider range of collision speeds than for bare mineral grains.

  17. The structural-phase state of iron-carbon coatings formed by the ultradispersed particles

    SciTech Connect

    Manakova, Irina A. Ozernoy, Alexey N. Tuleushev, Yuriy Zh. Vereshchak, Mikhail F. Volodin, Valeriy N. Zhakanbayev, Yeldar A.

    2014-10-27

    The methods of nuclear gamma-resonance spectroscopy, elemental microanalysis, and X-ray diffraction were used to study nanoscale coatings. The samples were prepared by magnetron sputtering of carbon and iron particles. They alternately were deposited on monocrystalline silicon or polycrystalline corundum substrate moving relative to the plasma flows in the form of sublayers with a thickness of less than 0.6 nm up to the total thickness of 150-500 nm. Solid solutions with the carbon concentrations of up to 7.5, 12.0, 17.6, and 23.9 at% were produced by co-precipitation of ultradispersed particles of iron and carbon. Using method of conversion electron Mössbauer spectroscopy, we detected the anisotropy of orientation of magnetic moments of iron atoms due to texturing of the formed coatings. The deviation of the crystallite orientation from the average value depends on the degree of carbonization. At 550°C, the pearlite eutectic α‐Fe(C)+Fe{sub 3}C is formed from the amorphous structure without formation of intermediate carbides. The relative content of cementite correlates with the amount of carbon in the coating. The formation of the solid solutions-alloys directly during the deposition process confirms the theory of thermal-fluctuation melting of small particles.

  18. Characterization of MgO-coated-LiCoO2 particles by analytical transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Taguchi, Noboru; Akita, Tomoki; Tatsumi, Kuniaki; Sakaebe, Hikari

    2016-10-01

    The surfaces of LiCoO2 particles were modified to improve the charge-discharge cycling properties of Li-ion batteries containing LiCoO2 cathodes. The sol-gel technique was used to modify the surface of LiCoO2 particles with magnesium oxide. Capacity retention during cycling of the magnesium oxide-coated LiCoO2 cathode was superior to that of a cathode comprising pristine LiCoO2. Moreover, results obtained from TEM measurements indicate that the Li concentration was relatively homogeneous in the magnesium oxide-coated LiCoO2 particles after cycling tests. The crystallographic planes of the coating were found to be coherently oriented with those of the substrate, MgO(111)[1-10]//LiCoO2(003)[100]. Therefore, we believe that a thin cover of Mg on the surface of LiCoO2 stabilizes the surface, contributing to the homogeneity of charge and discharge reactions.

  19. The Microstructure and Wear Resistance of Microarc Oxidation Composite Coatings Containing Nano-Hexagonal Boron Nitride (HBN) Particles

    NASA Astrophysics Data System (ADS)

    Li, Zhenwei; Di, Shichun

    2017-04-01

    The composite coatings containing HBN were prepared on 2024 aluminum alloy by microarc oxidation in the electrolyte with nano-HBN particles. The microstructure, surface roughness, phase composition, hardness, adhesion strength and wear resistance of composite coatings were analyzed by SEM, EDS, laser confocal microscope, XRD, Vickers hardness tester, scratch test and ball-on-disc abrasive tests. The results revealed that composite coatings were mainly composed of γ-Al2O3, α-Al2O3, mullite and HBN. With increasing the content of HBN particles in the electrolyte, the size and number of the pores on the surface of composite coatings decreased significantly. Compared to the MAO coatings without HBN, the composite coatings exhibited better wear resistance, as demonstrated by the lower friction coefficient and the lower wear rate.

  20. The Microstructure and Wear Resistance of Microarc Oxidation Composite Coatings Containing Nano-Hexagonal Boron Nitride (HBN) Particles

    NASA Astrophysics Data System (ADS)

    Li, Zhenwei; Di, Shichun

    2017-03-01

    The composite coatings containing HBN were prepared on 2024 aluminum alloy by microarc oxidation in the electrolyte with nano-HBN particles. The microstructure, surface roughness, phase composition, hardness, adhesion strength and wear resistance of composite coatings were analyzed by SEM, EDS, laser confocal microscope, XRD, Vickers hardness tester, scratch test and ball-on-disc abrasive tests. The results revealed that composite coatings were mainly composed of γ-Al2O3, α-Al2O3, mullite and HBN. With increasing the content of HBN particles in the electrolyte, the size and number of the pores on the surface of composite coatings decreased significantly. Compared to the MAO coatings without HBN, the composite coatings exhibited better wear resistance, as demonstrated by the lower friction coefficient and the lower wear rate.

  1. Modification of solid oxide fuel cell anodes with cerium oxide coatings

    NASA Astrophysics Data System (ADS)

    Tang, Ling

    A priority for research in solid oxide fuel cells (SOFCs) is to develop cells that can maintain adequate performance in sulfur-containing fuel streams. There has been evidence that cerium oxide in the anode or electrolyte is associated with sulfur tolerance of the cell, but the mechanism underlying this effect is not well understood. The objective of the present research is to show that the porous cermet SOFC anodes can be coated with cerium oxide films, so that the cell performance can be evaluated as a function of the anode structure and the microstructure of the film. Three types of anodes---Ni/yttria-stabilized zirconia (YSZ), Ni/gadolinia-doped ceria (GDC), and Ni/GDC with GDC interlayer were infiltrated with an aqueous solution to deposit nanocrystalline ceria films. The cells were then tested in hydrogen/nitrogen fuel containing hydrogen sulfide at levels up to 500 ppm. Modification of the anodes with thiol-terminated and trichlorosilane-terminated surfactants was explored. Different ceria film morphology was achieved for each surface treatment. In the cells that underwent performance testing, the thiol treatment promoted ceria film deposition, while the sulfonate treatment suppressed ceria deposition. Uniform ceria films up to 100 nm thick could be deposited in 48 h. Results on cell testing conditions, e.g. current, time, and H2S exposure were related to different anode structures and ceria coating morphologies. In general, the Ni/GDC anodes showed better performance than the Ni/YSZ anode. The introduction of ceria films often resulted in higher cell current and longer testing time, including operation under H2S exposure. Post-testing characterization revealed that, for some anodes, microstructure changes such as coarsening of Ni in the anode, migration of Ni to the anode surface, and depletion of Ni occurred. These changes in microstructure were irreversible and might account for permanent loss of cell performance. The presence of ceria films delayed these

  2. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2011-06-07

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  3. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  4. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard [Honeoye Falls, NY; Borup, Rodney Lynn [East Rochester, NY; Hulett, Jay S [Rochester, NY; Brady, Brian K. NY; Cunningham, Kevin M [Romeo, MI

    2011-06-07

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  5. The erosion performance of particle reinforced metal matrix composite coatings produced by co-deposition cold gas dynamic spraying

    NASA Astrophysics Data System (ADS)

    Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

    2017-02-01

    This work reports on the erosion performance of three particle reinforced metal matrix composite coatings, co-deposited with an aluminium binder via cold-gas dynamic spraying. The deposition of ceramic particles is difficult to achieve with typical cold spray techniques due to the absence of particle deformation. This issue has been overcome in the present study by simultaneously spraying the reinforcing particles with a ductile metallic binder which has led to an increased level of ceramic/cermet particles deposited on the substrate with thick (>400 μm) coatings produced. The aim of this investigation was to evaluate the erosion performance of the co-deposited coatings within a slurry environment. The study also incorporated standard metallographic characterisation techniques to evaluate the distribution of reinforcing particles within the aluminium matrix. All coatings exhibited poorer erosion performance than the uncoated material, both in terms of volume loss and mass loss. The Al2O3 reinforced coating sustained the greatest amount of damage following exposure to the slurry and recorded the greatest volume loss (approx. 2.8 mm3) out of all of the examined coatings. Despite the poor erosion performance, the WC-CoCr reinforced coating demonstrated a considerable hardness increase over the as-received AA5083 (approx. 400%) and also exhibited the smallest free space length between adjacent particles. The findings of this study reveal that the removal of the AA5083 matrix by the impinging silicon carbide particles acts as the primary wear mechanism leading to the degradation of the coating. Analysis of the wear scar has demonstrated that the damage to the soft matrix alloy takes the form of ploughing and scoring which subsequently exposes carbide/oxide particles to the impinging slurry.

  6. Partitioning behavior of aromatic components in jet fuel into diverse membrane-coated fibers.

    PubMed

    Baynes, Ronald E; Xia, Xin-Rui; Barlow, Beth M; Riviere, Jim E

    2007-11-01

    Jet fuel components are known to partition into skin and produce occupational irritant contact dermatitis (OICD) and potentially adverse systemic effects. The purpose of this study was to determine how jet fuel components partition (1) from solvent mixtures into diverse membrane-coated fibers (MCFs) and (2) from biological media into MCFs to predict tissue distribution. Three diverse MCFs, polydimethylsiloxane (PDMS, lipophilic), polyacrylate (PA, polarizable), and carbowax (CAR, polar), were selected to simulate the physicochemical properties of skin in vivo. Following an appropriate equilibrium time between the MCF and dosing solutions, the MCF was injected directly into a gas chromatograph/mass spectrometer (GC-MS) to quantify the amount that partitioned into the membrane. Three vehicles (water, 50% ethanol-water, and albumin-containing media solution) were studied for selected jet fuel components. The more hydrophobic the component, the greater was the partitioning into the membranes across all MCF types, especially from water. The presence of ethanol as a surrogate solvent resulted in significantly reduced partitioning into the MCFs with discernible differences across the three fibers based on their chemistries. The presence of a plasma substitute (media) also reduced partitioning into the MCF, with the CAR MCF system being better correlated to the predicted partitioning of aromatic components into skin. This study demonstrated that a single or multiple set of MCF fibers may be used as a surrogate for octanol/water systems and skin to assess partitioning behavior of nine aromatic components frequently formulated with jet fuels. These diverse inert fibers were able to assess solute partitioning from a blood substitute such as media into a membrane possessing physicochemical properties similar to human skin. This information may be incorporated into physiologically based pharmacokinetic (PBPK) models to provide a more accurate assessment of tissue dosimetry of

  7. Nanostructured Indium Oxide Coated Silicon Nanowire Arrays: A Hybrid Photothermal/Photochemical Approach to Solar Fuels.

    PubMed

    Hoch, Laura B; O'Brien, Paul G; Jelle, Abdinoor; Sandhel, Amit; Perovic, Douglas D; Mims, Charles A; Ozin, Geoffrey A

    2016-09-27

    The field of solar fuels seeks to harness abundant solar energy by driving useful molecular transformations. Of particular interest is the photodriven conversion of greenhouse gas CO2 into carbon-based fuels and chemical feedstocks, with the ultimate goal of providing a sustainable alternative to traditional fossil fuels. Nonstoichiometric, hydroxylated indium oxide nanoparticles, denoted In2O3-x(OH)y, have been shown to function as active photocatalysts for CO2 reduction to CO via the reverse water gas shift reaction under simulated solar irradiation. However, the relatively wide band gap (2.9 eV) of indium oxide restricts the portion of the solar irradiance that can be utilized to ∼9%, and the elevated reaction temperatures required (150-190 °C) reduce the overall energy efficiency of the process. Herein we report a hybrid catalyst consisting of a vertically aligned silicon nanowire (SiNW) support evenly coated by In2O3-x(OH)y nanoparticles that utilizes the vast majority of the solar irradiance to simultaneously produce both the photogenerated charge carriers and heat required to reduce CO2 to CO at a rate of 22.0 μmol·gcat(-1)·h(-1). Further, improved light harvesting efficiency of the In2O3-x(OH)y/SiNW films due to minimized reflection losses and enhanced light trapping within the SiNW support results in a ∼6-fold increase in photocatalytic conversion rates over identical In2O3-x(OH)y films prepared on roughened glass substrates. The ability of this In2O3-x(OH)y/SiNW hybrid catalyst to perform the dual function of utilizing both light and heat energy provided by the broad-band solar irradiance to drive CO2 reduction reactions represents a general advance that is applicable to a wide range of catalysts in the field of solar fuels.

  8. Fabrication of electrically conductive nickel-silver bimetallic particles via polydopamine coating.

    PubMed

    Kim, Sung Yeop; Kim, Jieun; Choe, Jaehoon; Byun, Young Chang; Seo, Jung Hyun; Kim, Do Hyun

    2013-11-01

    Inspired by adhesive proteins excreted by marine mussels, dopamine can act as a versatile surface modification agent for various organic and inorganic materials. By using adhesive polydopamine (PDA) as an intermediate layer, a simple and novel method for fabricating nickel-PDA-silver (Ni-PDA-Ag) bimetallic composite particles was developed. Ni-PDA-Ag bimetallic particles were fabricated by dispersing Ni particles in an aqueous dopamine solution followed by electroless Ag plating on the prepared Ni-PDA particles. A PDA layer with nano-meter thickness was deposited spontaneously on the surface of the Ni particles by oxidative self-polymerization of dopamine under alkaline conditions. Electroless Ag plating on the prepared Ni-PDA particles was carried out in the presence of a glucose solution as a reducing agent. Ni-PDA particles and Ni-PDA-Ag composite particles with a PDA intermediate layer were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), field-emission transmission electron microscopy (FE-TEM), and X-ray diffraction (XRD). In addition, the electrical conductivity of as-prepared composite particles was evaluated by a 4-point probe. The PDA layer deposited on the surface of Ni was confirmed by XPS spectra, FT-IR spectroscopy, and FE-TEM. FE-SEM images demonstrated that Ag nanoparticles were successfully plated on the PDA layer-coated Ni particles after the electroless Ag plating process. XRD patterns also confirmed the presence of Ag in a metallic state. In addition, the sheet resistance of as-prepared composite particles showed a tendency to decrease with increasing AgNO3 concentration.

  9. Thermochemical behavior of nano-sized aluminum-coated nickel particles

    NASA Astrophysics Data System (ADS)

    Sundaram, Dilip Srinivas; Puri, Puneesh; Yang, Vigor

    2014-05-01

    Molecular dynamics simulations are performed to investigate the thermochemical behavior of aluminum-coated nickel particles in the size range of 4-13 nm, beyond which asymptotic behavior is observed. The atomic interactions are captured using an embedded atom model. Emphasis is placed on the particle melting behavior, diffusion characteristics, and inter-metallic reactions. Results are compared with the corresponding properties of nickel-coated nano-aluminum particles. Melting of the shell, which is a heterogeneous process beginning at the outer surface of the particle, is followed by diffusion of aluminum and nickel atoms and inter-metallic reactions. The ensuing chemical energy heats up the particle under adiabatic conditions. The alloying reactions progressively transform the core-shell structured particle into a homogeneous alloy. The melting temperature of the shell is weakly dependent on the core size, but increases significantly with increasing shell thickness, from 750 K at 1 nm to 1,000 K at 3 nm. The core melts at a temperature comparable to the melting point of a nascent particle, contrary to the phenomenon of superheating observed for nickel-coated aluminum particles. The melting temperature of the core decreases from 1,730 to 1,500 K, when its diameter decreases from 10 to 7 nm. For smaller cores, the majority of nickel atoms participate in reactions before melting. The diffusion coefficient of nickel atoms in aluminum shell exhibits a temperature dependence of the form D = D 0 exp(- E A/ RT), with an activation energy of 43.65 kJ/mol and a pre-exponential factor of 1.77 × 10-7 m2/s. The adiabatic reaction temperature, also a size-dependent quantity, increases with increasing core diameter, attains a maximum value of 2,050 K at 5 nm, and decreases with further increase in the core diameter. The calculated values agree reasonably with those obtained via chemical equilibrium analysis. The burning time exhibits strong dependence of particle core size and

  10. Evaluation of Particle Counter Technology for Detection of Fuel Contamination Detection Utilizing Fuel System Supply Point

    DTIC Science & Technology

    2014-06-19

    VA : Coordinating Research Council, Inc. Vols. 2013 Aviation Technical Committee Meetings, May 2012. 10. Dallas, A .,Block, J., Klick, P., Grove, B ...utilizing Fuel System Supply Point Joel Schmitigal U S Army Tank Automotive Research DISTRIBUTION STATEMENT A . Approved for public release; distribution...AVAILABILITY STATEMENT Distribution Statement A . Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT In June 2013

  11. Evaluation of Additives to Eliminate Free Water from Aviation Fuel Light Obscuration Particle Counts

    DTIC Science & Technology

    2015-11-01

    contamination on light obscuration particle counting data. 15. SUBJECT TERMS fuel, JP-8, diesel , contamination, particulate, free water, absorption...mg/L for