WorldWideScience

Sample records for fuel-cladding chemical interaction

  1. Fuel clad chemical interactions in fast reactor MOX fuels

    Science.gov (United States)

    Viswanathan, R.

    2014-01-01

    Clad corrosion being one of the factors limiting the life of a mixed-oxide fast reactor fuel element pin at high burn-up, some aspects known about the key elements (oxygen, cesium, tellurium, iodine) in the clad-attack are discussed and many Fuel-Clad-Chemical-Interaction (FCCI) models available in the literature are also discussed. Based on its relatively superior predictive ability, the HEDL (Hanford Engineering Development Laboratory) relation is recommended: d/μm = ({0.507 ṡ [B/(at.% fission)] ṡ (T/K-705) ṡ [(O/M)i-1.935]} + 20.5) for (O/M)i ⩽ 1.98. A new model is proposed for (O/M)i ⩾ 1.98: d/μm = [B/(at.% fission)] ṡ (T/K-800)0.5 ṡ [(O/M)i-1.94] ṡ [P/(W cm-1)]0.5. Here, d is the maximum depth of clad attack, B is the burn-up, T is the clad inner surface temperature, (O/M)i is the initial oxygen-to-(uranium + plutonium) ratio, and P is the linear power rating. For fuels with [n(Pu)/n(M = U + Pu)] > 0.25, multiplication factors f are recommended to consider the potential increase in the depth of clad-attack.

  2. Cr plating technology for preventing Fuel Cladding Chemical Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Hwan; Ryu, Ho Jin; Jee, Seung Hyun; Cheon, Jin Sik; Lee, Byoung Oon; Lee, Chan Bock; Yang, Seong Woo [KAERI, Daejeon (Korea, Republic of)

    2010-11-15

    The objectives of the report are to analyze chrome electroplating technology in order to apply in the field of diffusion barrier to suppress Fuel-Cladding Chemical Interaction (FCCI). This report consists of the principle of the chrome electroplating, plating parameter and possibility of the barrier application. Chrome plating has been considered as one of the probable candidates in the field of barrier tube because of its simpleness, superior FCCI resistance, and effective coating performance at relatively low cost. However, cracks can be generate at the surface of the coating surface which reduces the coating performance. To minimize such a crack, controlling plating parameter like bath composition and bath temperature, current profile, and post-heat treatment has been reviewed. Concept for the application at the inner surface of the cladding has been also described. Based on the technology that suggested at the present report, optimizing plating parameter will be carried out. After the performance test like diffusion couple test of the metallic fuel, final barrier condition will be concluded and the fabrication of the prototype barrier tube will be conducted in the near future

  3. Status Report on the Fabrication of Fuel Cladding Chemical Interaction Test Articles for ATR Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-28

    FeCrAl alloys are a promising new class of alloys for light water reactor (LWR) applications due to their superior oxidation and corrosion resistance in high temperature environments. The current R&D efforts have focused on the alloy composition and processing routes to generate nuclear grade FeCrAl alloys with optimized properties for enhanced accident tolerance while maintaining properties needed for normal operation conditions. Therefore, the composition and processing routes must be optimized to maintain the high temperature steam oxidation (typically achieved by increasing the Cr and Al content) while still exhibiting properties conducive to normal operation in a LWR (such as radiation tolerance where reducing Cr content is favorable). Within this balancing act is the addition of understanding the influence on composition and processing routes on the FeCrAl alloys for fuel-cladding chemical interactions (FCCI). Currently, limited knowledge exists on FCCI for the FeCrAl-UO2 clad-fuel system. To overcome the knowledge gaps on the FCCI for the FeCrAl-UO2 clad-fuel system a series of fueled irradiation tests have been developed for irradiation in the Advanced Test Reactor (ATR) housed at the Idaho National Laboratory (INL). The first series of tests has already been reported. These tests used miniaturized 17x17 PWR fuel geometry rodlets of second-generation FeCrAl alloys fueled with industrial Westinghouse UO2 fuel. These rodlets were encapsulated within a stainless steel housing.To provide high fidelity experiments and more robust testing, a new series of rodlets have been developed deemed the Accident Tolerant Fuel Experiment #1 Oak Ridge National Laboratory FCCI test (ATF-1 ORNL FCCI). The main driving factor, which is discussed in detail, was to provide a radiation environment where prototypical fuel-clad interface temperatures are met while still maintaining constant contact between industrial fuel and the candidate cladding alloys

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Wei-Yang; Yang, Yong, E-mail: yongyang@ufl.edu

    2014-08-01

    Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V{sub 2}C. Diffusion couple tests at 660 °C for 100 h demonstrate that V{sub 2}C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

  6. Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

    Science.gov (United States)

    Lo, Wei-Yang; Yang, Yong

    2014-08-01

    Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V2C. Diffusion couple tests at 660 °C for 100 h demonstrate that V2C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

  7. High Temperature Fuel Cladding Chemical Interactions Between TRIGA Fuels and 304 Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Emmanuel [Idaho National Lab. (INL), Idaho Falls, ID (United States); Keiser, Jr., Dennis D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Forsmann, Bryan [Boise State Univ., ID (United States); Janney, Dawn E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Henley, Jody [Idaho National Lab. (INL), Idaho Falls, ID (United States); Woolstenhulme, Eric C. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-02-01

    High-temperature fuel-cladding chemical interactions (FCCI) between TRIGA (Training, Research, Isotopes, General Atomics) fuel elements and the 304 stainless steel (304SS) are of interest to develop an understanding of the fuel behavior during transient reactor scenarios. TRIGA fuels are composed of uranium (U) particles dispersed in a zirconium-hydride (Zr-H) matrix. In reactor, the fuel is encased in 304-stainless-steel (304SS) or Incoloy 800 clad tubes. At high temperatures, the fuel can readily interact with the cladding, resulting in FCCI. A number of FCCI can take place in this system. Interactions can be expected between the cladding and the Zr-H matrix, and/or between the cladding and the U-particles. Other interactions may be expected between the Zr-H matrix and the U-particles. Furthermore, the fuel contains erbium-oxide (Er-O) additions. Interactions can also be expected between the Er-O, the cladding, the Zr-H and the U-particles. The overall result is that very complex interactions may take place as a result of fuel and cladding exposures to high temperatures. This report discusses the characterization of the baseline fuel microstructure in the as-received state (prior to exposure to high temperature), characterization of the fuel after annealing at 950C for 24 hours and the results from diffusion couple experiments carries out at 1000C for 5 and 24 hours. Characterization was carried out via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with sample preparation via focused ion beam in situ-liftout-technique.

  8. Temperature and burnup correlated fuel-cladding chemical interaction in U-10ZR metallic fuel

    Science.gov (United States)

    Carmack, William J.

    Metallic fuels are proposed for use in advanced sodium cooled fast reactors and provide a number of advantages over other fuel types considering their fabricability, performance, recyclability, and safety. Resistance to cladding "breach" and subsequent release of fission products and fuel constituents to the nuclear power plant primary coolant system is a key performance parameter for a nuclear fuel system. In metallic fuel, FCCI weakens the cladding, especially at high power-high temperature operation, contributing to fuel pin breach. Empirical relationships for FCCI have been developed from a large body of data collected from in-pile (EBR-II) and out-of-pile experiments [1]. However, these relationships are unreliable in predicting FCCI outside the range of EBR-II experimental data. This dissertation examines new FCCI data extracted from the MFF-series of prototypic length metallic fuel irradiations performed in the Fast Flux Test Facility (FFTF). The fuel in these assemblies operated a temperature and burnup conditions similar to that in EBR-II but with axial fuel height three times longer than EBR-II experiments. Comparing FCCI formation data from FFTF and EBR-II provides new insight into FCCI formation kinetics. A model is developed combining both production and diffusion of lanthanides to the fuel-cladding interface and subsequent reaction with the cladding. The model allows these phenomena to be influenced by fuel burnup (lanthanide concentrations) and operating temperature. Parameters in the model are adjusted to reproduce measured FCCI layer thicknesses from EBR-II and FFTF. The model predicts that, under appropriate conditions, rate of FCCI formation can be controlled by either fission product transport or by the reaction rate of the interaction species at the fuel-cladding interface. This dissertation will help forward the design of metallic fuel systems for advanced sodium cooled fast reactors by allowing the prediction of FCCI layer formation in full

  9. Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

    Institute of Scientific and Technical Information of China (English)

    Jun Hwan Kim; Byoung Oon Lee; Chan Bock Lee; Seung Hyun Jee; Young Soo Yoon

    2012-01-01

    The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction (FCCI) behavior.Mischmetal (70Ce-30La) and Nd were prepared as rare earth elements.Diffusion couple testing was performed on the rare earth elements and cladding (9Cr2W steel) near the operation temperature of(sodium-cooled fast reactor) SFR fuel.The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated.Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law,describing the migration of the rare earth element.The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law.Rare earth materials could be used as a surrogate for high burnup metallic fuels,and the performance of the barrier material was demonstrated to be effective.

  10. Metallography and fuel cladding chemical interaction in fast flux test facility irradiated metallic U-10Zr MFF-3 and MFF-5 fuel pins

    Science.gov (United States)

    Carmack, W. J.; Chichester, H. M.; Porter, D. L.; Wootan, D. W.

    2016-05-01

    The Mechanistic Fuel Failure (MFF) series of metal fuel irradiations conducted in the Fast Flux Test Facility (FFTF) provides an important comparison between data generated in the Experimental Breeder Reactor (EBR-II) and that expected in a larger-scale fast reactor. The MFF fuel operated with a peak cladding temperature at the top of the fuel column, but developed peak burnup at the centerline of the core. This places the peak fuel temperature midway between the core center and the top of fuel, lower in the fuel column than in EBR-II experiments. Data from the MFF-3 and MFF-5 assemblies are most comparable to the data obtained from the EBR-II X447 experiment. The two X447 pin breaches were strongly influenced by fuel/cladding chemical interaction (FCCI) at the top of the fuel column. Post irradiation examination data from MFF-3 and MFF-5 are presented and compared to historical EBR-II data.

  11. Experimental assessment of fuel-cladding interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Elizabeth Sooby [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-29

    A range of fuel concepts designed to better tolerate accident scenarios and reactor transients are currently undergoing fundamental development at national laboratories as well as university and industrial partners. Pellet-clad mechanical and chemical interaction can be expected to affect fuel failure rates experienced during steady state operation, as well as dramatically impact the response of the fuel form under loss of coolant and other accident scenarios. The importance of this aspect of fuel design prompted research initiated by AFC in FY14 to begin exploratory efforts to characterize this phenomenon for candidate fuelcladding systems of immediate interest. Continued efforts in FY15 and FY17 aimed to better understand and simulate initial pellet-clad interaction with little-to-no pressure on the pellet-clad interface. Reported here are the results from 1000 h heat treatments at 400, 500, and 600°C of diffusion couples pairing UN with a FeCrAl alloy, SiC, and Zr-based cladding candidate sealed in evacuated quartz ampoules. No gross reactions were observed, though trace elemental contaminants were identified.

  12. Metallography and fuel cladding chemical interaction in fast flux test facility irradiated metallic U-10Zr MFF-3 and MFF-5 fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Carmack, W. J.; Chichester, H. M.; Porter, D. L.; Wootan, D. W.

    2016-05-01

    Abstract The Mechanistic Fuel Failure (MFF) series of metal fuel irradiations conducted in the Fast Flux Test Facility (FFTF) provides an important potential comparison between data generated in the Experimental Breeder Reactor (EBR-II) and that expected in a larger-scale fast reactor. The irradiations were the beginning tests to qualify U-10wt%Zr as a driver fuel for FFTF. The FFTF core, with a 91.4 cm tall fuel column and a chopped cosine neutron flux profile, operated with a peak cladding temperature at the top of the fuel column, but developed peak burnup at the centerline of the core. This places the peak fuel temperature midway between the core center and the top of fuel, lower in the fuel column than in previous EBR-II experiments that had a 32-cm height core. The MFF-3 and MFF-5 qualification assemblies operated in FFTF to >10 at% burnup, and performed very well with no cladding breaches. The MFF-3 assembly operated to 13.8 at% burnup with a peak inner cladding temperature of 643°C, and the MFF-5 assembly operated to 10.1 at% burnup with a peak inner cladding temperature of 651°C. Because of the very high operating temperatures for both the fuel and the cladding, data from the MFF assemblies are most comparable to the data obtained from the EBR-II X447 experiment, which experienced two pin breaches. The X447 breaches were strongly influenced by a large amount of fuel/cladding chemical interaction (FCCI). The MFF pins benefitted from different axial locations of high burnup and peak cladding temperature, which helped to reduce interdiffusion between rare earth fission products and stainless steel cladding. Post-irradiation examination evidence illustrates this advantage. Comparing other performance data of the long MFF pins to prior EBR-II test data, the MFF fuel inside the cladding grew less axially, and the gas release data did not reveal a definitive difference.

  13. Stability increase of fuel clad with zirconium oxynitride thin film by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jee, Seung Hyun [Department of Materials Science and Engineering, Yonsei University, 134 Sinchon Dong, Seoul 120-749 (Korea, Republic of); Materials Research and Education Center, Dept. of Mechanical Engineering, Auburn University, 275 Wilmore Labs, AL 36849-5341 (United States); Kim, Jun Hwan; Baek, Jong Hyuk [Recycled Fuel Development Division, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon, 305-600 (Korea, Republic of); Kim, Dong-Joo [Materials Research and Education Center, Dept. of Mechanical Engineering, Auburn University, 275 Wilmore Labs, AL 36849-5341 (United States); Kang, Seong Sik [Regulatory Research Division, Korea Institute of Nuclear Safety, 19, Guseong-Dong, Yuseong-Gu, Daejeon, 305-338 (Korea, Republic of); Yoon, Young Soo, E-mail: yoonys@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 134 Sinchon Dong, Seoul 120-749 (Korea, Republic of)

    2012-06-01

    A zirconium oxynitride (ZON) thin film was deposited onto HT9 steel as a cladding material by a metalorganic chemical vapor deposition (MOCVD) in order to prevent a fuel-clad chemical interaction (FCCI) between a U-10 wt% Zr metal fuel and a clad material. X-ray diffraction spectrums indicated that the mixture of structures of zirconium nitride, oxide and carbide in the MOCVD grown ZON thin films. Also, typical equiaxial grain structures were found in plane and cross sectional images of the as-deposited ZON thin films with a thickness range of 250-500 nm. A depth profile using auger electron microscopy revealed that carbon and oxygen atoms were decreased in the ZON thin film deposited with hydrogen gas flow. Diffusion couple tests at 800 Degree-Sign C for 25 hours showed that the as-deposited ZON thin films had low carbon and oxygen content, confirmed by the Energy Dispersive X-ray Spectroscopy, which showed a barrier behavior for FCCI between the metal fuel and the clad. This result suggested that ZON thin film cladding by MOCVD, even with the thickness below the micro-meter level, has a high possibility as an effective FCCI barrier. - Highlights: Black-Right-Pointing-Pointer Zirconium oxynitride (ZON) deposited by metal organic chemical vapor deposition. Black-Right-Pointing-Pointer Prevention of fuel cladding chemical interaction (FCCI) investigated. Black-Right-Pointing-Pointer Interfusion reduced by between metal fuel (U-10 wt% Zr) and a HT9 cladding material. Black-Right-Pointing-Pointer Hydrogenation of the ZON during growth improved the FCCI barrier performance.

  14. Direct observation of fuel-cladding mechanical interaction (FCMI) in mixed-oxide fast reactor fuel pins

    Science.gov (United States)

    Foster, J. P.; Nayak, U. P.

    1981-10-01

    The WSA-1 and WSA-2 fuel pins exhibit experimental evidence of fuel-cladding mechanical interaction (FCMI) as a result of steady-state irradiation. The direct FCMI evidence involves a comparison of local axial and hoop mechanical strain profiles. The determination of the local axial mechanical strain was possible because of the placement of axial hardness marks 12.7 mm apart along a line parallel to the tubing axis spanning the fuel column. The measured cladding local axial and hoop mechanical deformations were the same within experimental error. The experimental results are in contrast to gas pressurized tube data which exhibit no axial mechanical deformation. A substantial amount of indirect evidence further illustrating the influence of FCMI on the cladding mechanical strain profile is also discussed. The conditions leading to steady-state FCMI are: high fuel smear density (i.e. low fuel-cladding gaps and/or high fuel pellet density), thin wall cladding, low cladding swelling and low fission gas pressure.

  15. In-core measurements of fuel-clad interactions in the Halden reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bennett Peter

    2008-10-15

    A combination of on-line measurement techniques was used to demonstrate AOA in the Halden reactor: - Diameter gauge to demonstrate crud deposition - Coolant flow and temperature measurements to show effect of crud on thermal-hydraulic conditions - Neutron detectors to show power depression caused by boron in the crud. - Coolant chemistry analyses provided supporting evidence of AOA - Lithium return during shutdown - PIE showed that the type of crud observed in US plants suffering severe AOA can be reproduced. Loop systems allow testing under LWR thermal-hydraulic and water chemistry conditions. - A combination of on-line instrumentation allows measurements of complicated phenomena, egPWR AOA. - Techniques are under development to allow on-line measurements of fuel clad corrosion

  16. EPRI fuel cladding integrity program

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R. [Electric Power Research Institute, Palo Alto, CA (United States)

    1997-01-01

    The objectives of the EPRI fuel program is to supplement the fuel vendor research to assure that utility economic and operational interests are met. To accomplish such objectives, EPRI has conducted research and development efforts to (1) reduce fuel failure rates and mitigate the impact of fuel failures on plant operation, (2) provide technology to extend burnup and reduce fuel cycle cost. The scope of R&D includes fuel and cladding. In this paper, only R&D related to cladding integrity will be covered. Specific areas aimed at improving fuel cladding integrity include: (1) Fuel Reliability Data Base; (2) Operational Guidance for Defective Fuel; (3) Impact of Water Chemistry on Cladding Integrity; (4) Cladding Corrosion Data and Model; (5) Cladding Mechanical Properties; and (6) Transient Fuel Cladding Response.

  17. Characterization of LWRS Hybrid SiC-CMC-Zircaloy-4 Fuel Cladding after Gamma Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Isabella J van Rooyen

    2012-09-01

    The purpose of the gamma irradiation tests conducted at the Idaho National Laboratory (INL) was to obtain a better understanding of chemical interactions and potential changes in microstructural properties of a mock-up hybrid nuclear fuel cladding rodlet design (unfueled) in a simulated PWR water environment under irradiation conditions. The hybrid fuel rodlet design is being investigated under the Light Water Reactor Sustainability (LWRS) program for further development and testing of one of the possible advanced LWR nuclear fuel cladding designs. The gamma irradiation tests were performed in preparation for neutron irradiation tests planned for a silicon carbide (SiC) ceramic matrix composite (CMC) zircaloy-4 (Zr-4) hybrid fuel rodlet that may be tested in the INL Advanced Test Reactor (ATR) if the design is selected for further development and testing

  18. Characterization of Hydrogen Content in ZIRCALOY-4 Nuclear Fuel Cladding

    Science.gov (United States)

    Pfeif, E. A.; Lasseigne, A. N.; Krzywosz, K.; Mader, E. V.; Mishra, B.; Olson, D. L.

    2010-02-01

    Assessment of hydrogen uptake of underwater nuclear fuel clad and component materials will enable improved monitoring of fuel health. Zirconium alloys are used in nuclear reactors as fuel cladding, fuel channels, guide tubes and spacer grids, and are available for inspection in spent fuel pools. With increasing reactor exposure zirconium alloys experience hydrogen ingress due to neutron interactions and water-side corrosion that is not easily quantified without destructive hot cell examination. Contact and non-contact nondestructive techniques, using Seebeck coefficient measurements and low frequency impedance spectroscopy, to assess the hydrogen content and hydride formation within zircaloy 4 material that are submerged to simulate spent fuel pools are presented.

  19. Chemical thermodynamics of the system Cs--U--Zr--H--I--O in the light water reactor fuel-cladding gap

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; Lindemer, T.B.

    1978-10-01

    Equilibrium thermodynamic calculations were performed on the Cs-U-Zr-H-I-O system that is assumed to exist in the fuel-cladding gap of light water reactor fuel under in-reactor, steam, and 50% steam--50% air conditions. The in-reactor oxygen potential is assumed to be controlled by either UO/sub 2+x/ + Cs/sub 2/UO/sub 4/ or Zr + ZrO/sub 2/. The important condensed phases in-reactor are UO/sub 2+x/, Cs/sub 2/UO/sub 4/, and CsI, and the major gaseous species are Cs, Cs/sub 2/, CsI, and Cs/sub 2/I/sub 2/. The presence of steam does not alter these species, although CsOH also becomes a major gaseous species. In a 50% steam--50% air mixture, the equilibrium condensed phases are U/sub 3/O/sub 8/ or UO/sub 3/ and Cs/sub 2/U/sub 15/O/sub 46/. Under a nonequilibrium situation where zirconium metal can react with iodine, ZrO/sub 3/ or liquid ZrI/sub 2/ is present, and the gaseous species ZrI/sub 3/ and ZrI/sub 4/ have large partial pressures.

  20. Simulations of Failure via Three-Dimensional Cracking in Fuel Cladding for Advanced Nuclear Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hongbing [Univ. of Texas, Austin, TX (United States); Bukkapatnam, Satish; Harimkar, Sandip; Singh, Raman; Bardenhagen, Scott

    2014-01-09

    Enhancing performance of fuel cladding and duct alloys is a key means of increasing fuel burnup. This project will address the failure of fuel cladding via three-dimensional cracking models. Researchers will develop a simulation code for the failure of the fuel cladding and validate the code through experiments. The objective is to develop an algorithm to determine the failure of fuel cladding in the form of three-dimensional cracking due to prolonged exposure under varying conditions of pressure, temperature, chemical environment, and irradiation. This project encompasses the following tasks: 1. Simulate 3D crack initiation and growth under instantaneous and/or fatigue loads using a new variant of the material point method (MPM); 2. Simulate debonding of the materials in the crack path using cohesive elements, considering normal and shear traction separation laws; 3. Determine the crack propagation path, considering damage of the materials incorporated in the cohesive elements to allow the energy release rate to be minimized; 4. Simulate the three-dimensional fatigue crack growth as a function of loading histories; 5. Verify the simulation code by comparing results to theoretical and numerical studies available in the literature; 6. Conduct experiments to observe the crack path and surface profile in unused fuel cladding and validate against simulation results; and 7. Expand the adaptive mesh refinement infrastructure parallel processing environment to allow adaptive mesh refinement at the 3D crack fronts and adaptive mesh merging in the wake of cracks. Fuel cladding is made of materials such as stainless steels and ferritic steels with added alloying elements, which increase stability and durability under irradiation. As fuel cladding is subjected to water, chemicals, fission gas, pressure, high temperatures, and irradiation while in service, understanding performance is essential. In the fast fuel used in advanced burner reactors, simulations of the nuclear

  1. Advanced LWR Nuclear Fuel Cladding System Development Trade-Off Study

    Energy Technology Data Exchange (ETDEWEB)

    Kristine Barrett; Shannon Bragg-Sitton

    2012-09-01

    The Advanced Light Water Reactor (LWR) Nuclear Fuel Development Research and Development (R&D) Pathway encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. To achieve significant operating improvements while remaining within safety boundaries, significant steps beyond incremental improvements in the current generation of nuclear fuel are required. Fundamental improvements are required in the areas of nuclear fuel composition, cladding integrity, and the fuel/cladding interaction to allow power uprates and increased fuel burn-up allowance while potentially improving safety margin through the adoption of an “accident tolerant” fuel system that would offer improved coping time under accident scenarios. With a development time of about 20 – 25 years, advanced fuel designs must be started today and proven in current reactors if future reactor designs are to be able to use them with confidence.

  2. Development of advanced LWR fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yong Hwan; Park, S. Y.; Lee, M. H. [and others

    2000-04-01

    This report describes the results from evaluating the preliminary Zr-based alloys to develop the advanced Zr-based alloys for the nuclear fuel claddings, which should have good corrosion resistance and mechanical properties at high burn-up over 70,000MWD/MTU. It also includes the results from the basic studies for optimizing the processes which are involved in the development of the advanced Zr-based alloys. Ten(10) kinds of candidates for the alloys of which performance is over that of the existing Zircaloy-4 or ZIRLO alloy were selected out of the preliminary alloys of 150 kinds which were newly designed and repeatedly manufactured and evaluated to find out the promising alloys. First of all, the corrosion tests on the preliminary alloys were carried out to evaluate their performance in both pure water and LiOH solution at 360 deg C and in steam at 400 deg C. The tensile tests were performed on the alloys which proved to be good in the corrosion resistance. The creep behaviors were tested at 400 deg C for 10 days with the application of constant load on the samples which showed good performance in the corrosion resistance and tensile properties. The effect of the final heat treatment and A-parameters as well as Sn or Nb on the corrosion resistance, tensile properties, hardness, microstructures of the alloys was evaluated for some alloys interested. The other basic researches on the oxides, electrochemical properties, corrosion mechanism, and the establishment of the phase diagrams of some alloys were also carried out.

  3. Preliminary study of mechanical behavior for Cr coated Zr-4 Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do-Hyoung; Kim, Hak-Sung [Hanyang Univ., Seoul (Korea, Republic of); Kim, Hyo-Chan; Yang, Yong-Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    To decrease the oxidation rate of Zr-based alloy components, many concepts of accident tolerant fuel (ATF) such as Mo-Zr cladding, SiC/SiCf cladding and iron-based alloy cladding are under development. One of the promised concept is the coated cladding which can remarkably increase the corrosion and wear resistance. Recently, KAERI is developing the Cr coated Zircaloy cladding as accident tolerance cladding. To coat the Cr powder on the Zircaloy, 3D laser coating technology has been employed because it is possible to make a coated layer on the tubular cladding surface by controlling the 3-diminational axis. Therefore, for this work, the mechanical integrity of Cr coated Zircaloy should be evaluated to predict the safety of fuel cladding during the operating or accident of nuclear reactor. In this work, the mechanical behavior of the Cr coated Zircaloy cladding has been studied by using finite element analysis (FEA). The ring compression test (RCT) of fuel cladding was simulated to evaluate the validity of mechanical properties of Zr-4 and Cr, which were referred from the literatures and experimental reports. In this work, the mechanical behavior of the Cr coated Zircaloy cladding has been studied by using finite element analysis (FEA). The ring compression test (RCT) of fuel cladding was simulated to evaluate the validity of mechanical properties of Zr-4 and Cr. The pellet-clad mechanical interaction (PCMI) properties of Cr coated Zr-4 cladding were investigated by thermo-mechanical finite element analysis (FEA) simulation. The mechanical properties of Zr-4 and Cr was validated by simulation of ring compression test (RCT) of fuel cladding.

  4. Mechanical behavior of aluminum-bearing ferritic alloys for accident-tolerant fuel cladding applications

    Science.gov (United States)

    Guria, Ankan

    Nuclear power currently provides about 13% of electrical power worldwide. Nuclear reactors generating this power traditionally use Zirconium (Zr) based alloys as the fuel cladding material. Exothermic reaction of Zr with steam under accident conditions may lead to production of hydrogen with the possibility of catastrophic consequences. Following the Fukushima-Daiichi incident, the exploration of accident-tolerant fuel cladding materials accelerated. Aluminum-rich (around 5 wt. %) ferritic steels such as Fecralloy, APMT(TM) and APM(TM) are considered as potential materials for accident-tolerant fuel cladding applications. These materials create an aluminum-based oxide scale protecting the alloy at elevated temperatures. Tensile deformation behavior of the above alloys was studied at different temperatures (25-500 °C) at a strain rate of 10-3 s-1 and correlated with microstructural characteristics. Higher strength and decent ductility of APMT(TM) led to further investigation of the alloy at various combination of strain rates and temperatures followed by fractography and detailed microscopic analyses. Serrations appeared in the stress-strain curves of APMT(TM) and Fecralloy steel tested in a limited temperature range (250-400 °C). The appearance of serrations is explained on the basis of dynamic strain aging (DSA) effect due to solute-dislocation interactions. The research in this study is being performed using the funds received from the US DOE Office of Nuclear Energy's Nuclear Energy University Programs (NEUP).

  5. Modeling the mechanical behaviour of CANDU fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Holt, R.A. [Queen' s Univ., Dept. of Mechanical Engineering, Kingston, Ontario (Canada)

    2003-07-01

    Models for the mechanical behaviour of fuel cladding were developed in the period 1973-1983 by staff at AECL CRNL. The models for the mechanical properties of fuel cladding during normal operation were a by-product of programs during the period 1970-1975 to understand the origin of fuel-cladding defects caused by power ramps at Douglas Point and Pickering A. Models for accident conditions were, initially, based heavily on mechanical properties data generated by McGill University and Westinghouse Canada under contract to AECL in the late 1960's and early 1970's and attempts to interpret the data in terms of the underlying deformation mechanisms. The model for normal operating conditions was embodied in the ELESTRES/ELESIM series of codes, and the models for accident conditions were embodied in NIRVANA. (author)

  6. BISON Investigation of the Effect of the Fuel- Cladding Contact Irregularities on the Peak Cladding Temperature and FCCI Observed in AFC-3A Rodlet 4

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, Pavel G. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    The primary objective of this report is to document results of BISON analyses supporting Fuel Cycle Research and Development (FCRD) activities. Specifically, the present report seeks to provide explanation for the microstructural features observed during post irradiation examination of the helium-bonded annular U-10Zr fuel irradiated during the AFC-3A experiment. Post irradiation examination of the AFC-3A rodlet revealed microstructural features indicative of the fuel-cladding chemical interaction (FCCI) at the fuel-cladding interface. Presence of large voids was also observed in the same locations. BISON analyses were performed to examine stress and temperature profiles and to investigate possible correlation between the voids and FCCI. It was found that presence of the large voids lead to a formation of circumferential temperature gradients in the fuel that may have redirected migrating lanthanides to the locations where fuel and cladding are in contact. Resulting localized increase of lanthanide concentration is expected to accelerate FCCI. The results of this work provide important guidance to the post irradiation examination studies. Specifically, the hypothesis of lanthanides being redirected from the voids to the locations where the fuel and the cladding are in contact should be verified by conducting quantitative electron microscopy or Electron Probe Micro-Analyzer (EPMA). The results also highlight the need for computer models capable of simulating lanthanide diffusion in metallic fuel and establish a basis for validation of such models.

  7. Improvement in PCI property of PWR fuel cladding by texture control

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, S. (Kansai Electric Power Co., Inc., Osaka (Japan)); Abeta, S.; Ozawa, M.; Takahashi, T.

    1993-09-01

    Effects of texture on out-of-pile Stress Corrosion Cracking (SCC) resistance in Zircaloy fuel cladding tube and the Pellet-Clad Interaction (PCI) property of a fuel rod using texture controlled cladding tube under power ramp conditions are described. The cladding tube with radial texture, which means that the c-axis of hcp crystal of Zr is highly concentrated in the radial direction of the tube, showed excellent performance in out-of-pile SCC tests and power ramp tests. (author).

  8. PFR fuel cladding transient test results and analysis

    Science.gov (United States)

    Cannon, N. S.; Hunter, C. W.; Kear, K. L.; Wood, M. H.

    1986-05-01

    Fuel Cladding Transient Tests (FCTT) were performed on M316 cladding specimens obtained from mixed-oxide fuel pins irradiated in the Prototype Fast Reactor (PFR) to burnups of 4 and 9 atom percent. In these tests, specimens of fuel cladding were pressurized and heated until failure occurred. Samples of cladding from PFR fuel pins exhibited generally greater strength and ductility than specimens from Experimental Breeder Reactor-II (EBR-II) mixed-oxide fuel pins tested under similar conditions. Apparently, the PFR cladding properties were not degraded by a fuel adjacency effect (FAE) observed in fuel pin cladding from EBR-II irradiations. A recently developed model of grain boundary cavity growth was used to predict the results of the tests conducted on PFR cladding. It was found that the predicted failure temperatures for the relevant internal pressures were in good agreement with experimental failure temperatures.

  9. Water-moderated reactor fuel cladding reliability study

    OpenAIRE

    Бакутяк, Елена Викторовна; Пелых, Сергей Николаевич

    2014-01-01

    Considering the fuel element, averaged by fuel assembly (FA) of water-moderated reactor with the power of 1000 MW (VVER-1000), the number of fuel elements with the greatest cladding failure probability after 4 operation years at Khmelnitsky NPP-2 (KNPP-2) is found. This will allow to calculate the fuel cladding failure probability and determine the most likely cladding damages, which will enable to improve the performance and economic indexes of VVER.The novelty of the paper lies in calculati...

  10. Microbial Biofilm Growth on Irradiated, Spent Nuclear Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    S.M. Frank

    2009-02-01

    A fundamental criticism regarding the potential for microbial influenced corrosion in spent nuclear fuel cladding or storage containers concerns whether the required microorganisms can, in fact, survive radiation fields inherent in these materials. This study was performed to unequivocally answer this critique by addressing the potential for biofilm formation, the precursor to microbial-influenced corrosion, in radiation fields representative of spent nuclear fuel storage environments. This study involved the formation of a microbial biofilm on irradiated spent nuclear fuel cladding within a hot cell environment. This was accomplished by introducing 22 species of bacteria, in nutrient-rich media, to test vessels containing irradiated cladding sections and that was then surrounded by radioactive source material. The overall dose rate exceeded 2 Gy/h gamma/beta radiation with the total dose received by some of the bacteria reaching 5 × 103 Gy. This study provides evidence for the formation of biofilms on spent-fuel materials, and the implication of microbial influenced corrosion in the storage and permanent deposition of spent nuclear fuel in repository environments.

  11. Development Status of Accident Tolerant Fuel Cladding for LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jung-Hwan; Yang, Jae-Ho; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Hydrogen explosions and the release of radionuclides are caused by severe damage of current nuclear fuels, which are composed of fuel pellets and fuel cladding, during an accident. To reduce the damage to the public, the fuels have to enhance their integrity under an accident environment. Enhanced accident tolerance fuels (ATFs) can tolerate a loss of active cooling in the reactor core for a considerably longer time period during design-basis and beyond design-basis events while maintaining or improving the fuel performance during normal operations as well as operational transients, in comparison with the current UO{sub 2}-Zr alloy system used in the LWR. Surface modified Zr cladding as a new concept was suggested to apply an enhanced ATF cladding. The aim of the partial ODS treatment is to increase the high-temperature strength to suppress the ballooning/rupture behavior of fuel cladding during an accident event. The target of the surface coating is to increase the corrosion resistance during normal operation and increase the oxidation resistance during an accident event. The partial ODS treatment of Zircaloy-4 cladding can be produced using a laser beam scanning method with Y2O3 powder, and the surface Cr-alloy and Cr/FeCrAl coating on Zircaloy-4 cladding can be obtained after the development of 3D laser coating and arc ion plating technologies.

  12. Characterization of Fuel-Cladding Bond Strength Using Laser Shock

    Energy Technology Data Exchange (ETDEWEB)

    James A. Smith; David L. Cottle; Barry H. Rabin

    2014-04-01

    This paper describes new laser-based capabilities for characterization of fuel-cladding bond strength in nuclear fuels, and presents preliminary results obtained from studies on as-fabricated monolithic fuel consisting of uranium-10 wt.% molybdenum alloys clad in 6061 aluminum by hot isostatic pressing. Two complementary experimental methods are employed, laser-shock testing and laser-ultrasonic imaging. Measurements are spatially localized, non-contacting and require minimum specimen preparation, and are therefore ideally suited for applications involving radioactive materials, including irradiated materials. The theoretical principles and experimental approaches employed in characterization of nuclear fuel plates are described. The ability to measure layer thicknesses, elastic properties of the constituents, and the location and nature of laser-shock induced debonds is demonstrated, and preliminary bond strength measurement results are discussed.

  13. A state of the Art report on Manufacturing technology of high burn-up fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Ho; Nam, Cheol; Baek, Jong Hyuk; Choi, Byung Kwon; Park, Sang Yoon; Lee, Myung Ho; Jeong, Yong Hwan

    1999-09-01

    In order to manufacturing the prototype fuel cladding, overall manufacturing processes and technologies should be thoroughly understood on the manufacturing processes and technologies of foreign cladding tubes. Generally, the important technology related to fuel cladding tube manufacturing processes for PWRs/PHWRs is divided into three stages. The first stage is to produce the zirconium sponge from zirconium sand, the second stage is to produce the zircaloy shell or TREX from zirconium sponge ingot and finally, cladding is produced from TREX or zircaloy shell. Therefore, the manufacturing processes including the first and second stages are described in brief in this technology report in order to understand the whole fuel cladding manufacturing processes. (author)

  14. A state of the Art report on Manufacturing technology of high burn-up fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Ho; Nam, Cheol; Baek, Jong Hyuk; Choi, Byung Kwon; Park, Sang Yoon; Lee, Myung Ho; Jeong, Yong Hwan

    1999-09-01

    In order to manufacturing the prototype fuel cladding, overall manufacturing processes and technologies should be thoroughly understood on the manufacturing processes and technologies of foreign cladding tubes. Generally, the important technology related to fuel cladding tube manufacturing processes for PWRs/PHWRs is divided into three stages. The first stage is to produce the zirconium sponge from zirconium sand, the second stage is to produce the zircaloy shell or TREX from zirconium sponge ingot and finally, cladding is produced from TREX or zircaloy shell. Therefore, the manufacturing processes including the first and second stages are described in brief in this technology report in order to understand the whole fuel cladding manufacturing processes. (author)

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

    Science.gov (United States)

    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 accident tolerance to nuclear fuel cladding.

  16. Characterization of Cassini GPHS Fueled-Clad Production Girth Welds

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Ferreira, E.A.

    2000-03-23

    Fueled clads for radioisotope power systems are produced by encapsulating {sup 238}PuO{sub 2} in iridium alloy cups, which are joined at their equators by gas tungsten arc welding. Cracking problems at the girth weld tie-in area during production of the Galileo/Ulysses GPHS capsules led to the development of a first-generation ultrasonic test for girth weld inspection at the Savannah River Plant. A second-generation test and equipment with significantly improved sensitivity and accuracy were jointly developed by the Oak Ridge Y-12 Plant and Westinghouse Savannah River Company for use during the production of Cassini GPHS capsules by the Los Alamos National Laboratory. The test consisted of Lamb wave ultrasonic scanning of the entire girth weld from each end of the capsule combined with a time-of-flight evaluation to aid in characterizing nonrelevant indications. Tangential radiography was also used as a supplementary test for further evaluation of reflector geometry. Each of the 317 fueled GPHS capsules, which were girth welded for the Cassini Program, was subjected to a series of nondestructive tests that included visual, dimensional, helium leak rate, and ultrasonic testing. Thirty-three capsules were rejected prior to ultrasonic testing. Of the 44 capsules rejected by the standard ultrasonic test, 22 were upgraded to flight quality through supplementary testing for an overall process acceptance rate of 82.6%. No confirmed instances of weld cracking were found.

  17. Tensile Hoop Behavior of Irradiated Zircaloy-4 Nuclear Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, Roger A [ORNL; Hendrich, WILLIAM R [ORNL; Packan, Nicolas H [ORNL

    2007-03-01

    A method for evaluating the room temperature ductility behavior of irradiated Zircaloy-4 nuclear fuel cladding has been developed and applied to evaluate tensile hoop strength of material irradiated to different levels. The test utilizes a polyurethane plug fitted within a tubular cladding specimen. A cylindrical punch is used to compress the plug axially, which generates a radial displacement that acts upon the inner diameter of the specimen. Position sensors track the radial displacement of the specimen outer diameter as the compression proceeds. These measurements coupled with ram force data provide a load-displacement characterization of the cladding response to internal pressurization. The development of this simple, cost-effective, highly reproducible test for evaluating tensile hoop strain as a function of internal pressure for irradiated specimens represents a significant advance in the mechanical characterization of irradiated cladding. In this project, nuclear fuel rod assemblies using Zircaloy-4 cladding and two types of mixed uranium-plutonium oxide (MOX) fuel pellets were irradiated to varying levels of burnup. Fuel pellets were manufactured with and without thermally induced gallium removal (TIGR) processing. Fuel pellets manufactured by both methods were contained in fuel rod assemblies and irradiated to burnup levels of 9, 21, 30, 40, and 50 GWd/MT. These levels of fuel burnup correspond to fast (E > 1 MeV) fluences of 0.27, 0.68, 0.98, 1.4 and 1.7 1021 neutrons/cm2, respectively. Following irradiation, fuel rod assemblies were disassembled; fuel pellets were removed from the cladding; and the inner diameter of cladding was cleaned to remove residue materials. Tensile hoop strength of this cladding material was tested using the newly developed method. Unirradiated Zircaloy-4 cladding was also tested. With the goal of determining the effect of the two fuel types and different neutron fluences on clad ductility, tensile hoop strength tests were

  18. A Multi-Layered Ceramic Composite for Impermeable Fuel Cladding for COmmercial Wate Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Feinroth, Herbert

    2008-03-03

    A triplex nuclear fuel cladding is developed to further improve the passive safety of commercial nuclear plants, to increase the burnup and durablity of nuclear fuel, to improve the power density and economics of nuclear power, and to reduce the amount of spent fuel requiring disposal or recycle.

  19. Surface modification techniques for increased corrosion tolerance of zirconium fuel cladding

    Science.gov (United States)

    Carr, James Patrick, IV

    Corrosion is a major issue in applications involving materials in normal and severe environments, especially when it involves corrosive fluids, high temperatures, and radiation. Left unaddressed, corrosion can lead to catastrophic failures, resulting in economic and environmental liabilities. In nuclear applications, where metals and alloys, such as steel and zirconium, are extensively employed inside and outside of the nuclear reactor, corrosion accelerated by high temperatures, neutron radiation, and corrosive atmospheres, corrosion becomes even more concerning. The objectives of this research are to study and develop surface modification techniques to protect zirconium cladding by the incorporation of a specific barrier coating, and to understand the issues related to the compatibility of the coatings examined in this work. The final goal of this study is to recommend a coating and process that can be scaled-up for the consideration of manufacturing and economic limits. This dissertation study builds on previous accident tolerant fuel cladding research, but is unique in that advanced corrosion methods are tested and considerations for implementation by industry are practiced and discussed. This work will introduce unique studies involving the materials and methods for accident tolerant fuel cladding research by developing, demonstrating, and considering materials and processes for modifying the surface of zircaloy fuel cladding. This innovative research suggests that improvements in the technique to modify the surface of zirconium fuel cladding are likely. Three elements selected for the investigation of their compatibility on zircaloy fuel cladding are aluminum, silicon, and chromium. These materials are also currently being investigated at other labs as alternate alloys and coatings for accident tolerant fuel cladding. This dissertation also investigates the compatibility of these three elements as surface modifiers, by comparing their microstructural and

  20. A micromechanical model for predicting hydride embrittlement in nuclear fuel cladding material

    Science.gov (United States)

    Chan, K. S.

    1996-01-01

    A major concern about nuclear fuel cladding under waste repository conditions is that the slow cooling rate anticipated in the repository may lead to the formation of excessive radial hydrides, and cause embrittlement of the cladding materials. In this paper, the development of a micromechanical model for predicting hydride-induced embrittlement in nuclear fuel cladding is presented. The important features of the proposed model are: (1) the capability to predict the orientation, morphology, and types of hydrides under the influence of key variables such as cooling rate, internal pressure, and time, and (2) the ability to predict the influence of hydride orientation and morphology on the tensile ductility and fracture toughness of the cladding material. Various model calculations are presented to illustrate the characteristics and utilities of the proposed methodology. A series of experiments was also performed to check assumptions used and to verify some of the model predictions.

  1. Temperature limits for LMFBR fuel cladding under upset and emergency operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Govindarajan, S.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam Tamilnadu (India). Nuclear Systems Division

    1996-07-01

    LMFBR fuel pin cladding tube is subjected to high transient temperatures during incidents such as pump trip, pump to grid plate pipe rupture etc. It is required to know temperature limits under such transient operating conditions for components involved while analyzing such incidents. A methodology for deriving such limits for fuel clad tube is worked out in this paper by making use of the transient damage correlation proposed by W.F. Brizes et. al.

  2. Construction of in-situ creep strain test facility for the SFR fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Gyu; Heo, Hyeong Min; Kim, Jun Hwan; Kim, Sung Ho [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, in-situ laser inspection creep test machine was developed for the measuring the creep strain of SFR fuel cladding materials. Ferritic-martensitic steels are being considered as an attractive candidate material for a fuel cladding of a SFR due to their low expansion coefficients, high thermal conductivities and excellent irradiation resistances to a void swelling. HT9 steel (12CrMoVW) is initially developed as a material for power plants in Europe in the 1960. This steel has experienced to expose up to 200dpa in FFTE and EBR-II. Ferritic-Martensitic steel's maximum creep strength in existence is 180Mpa for 106 hour 600 .deg., but HT9 steel is 60Mpa. Because SFR is difficult to secure in developing and applying materials, HT9 steel has accumulated validated data and is suitable for SFR component. And also, because of its superior dimensional stability against fast neutron irradiation, Ferritic-martensitic steel of 9Cr and 12Cr steels, such as HT9 and FC92(12Cr-2W) are preferable to utilize in the fuel cladding of an SFR in KAERI. The pressurized thermal creep test of HT9 and FC92 claddings are being conducted in KAERI, but the change of creep strain in cladding is not easy to measure during the creep test due to its pressurized and closed conditions. In this paper, in-situ laser inspection pressurized creep test machine developed for SFR fuel cladding specimens is described. Moreover, the creep strain rate of HT9 at 650 .deg. C was examined from the in-situ laser inspection pressurized creep test machine.

  3. Feasibility Study on the Sodium Compatibility Test for Fuel Cladding of SFR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Hwan; Shin, Sang Hun; Park, Sang Gyu; Ryu, Woo Seog; Kim, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    A Sodium-cooled Fast Reactor (SFR), a reactor that uses fast neutrons as a fission process, is considered one of the most probable candidates in next-generation reactors because it can maximize the uranium utilization when compared to conventional water reactor. Liquid sodium is used as a coolant in a SFR, because it has superior efficiency of fast neutron economy and high thermal conductivity, which enables a high power core design. However, previous research reported that fuel cladding materials like austenitic and ferritic-martensitic steel (FMS) react sodium coolant so that it results in the loss of the thickness, intergranular attack, and carburization or decarburization process to induce the change of the mechanical property. Fuel cladding, a seamless tube which has approximately 0.5mm in thickness and 3m in length is the component which covers fuel to protect radioactive species from being released. Because of its smaller thickness, the mechanical properties of the cladding are easily affected by the small changes of material property. This paper summarizes the status of sodium-material compatibility facility and proposes the optimal option in the case of the SFR fuel cladding. Previous researches revealed that assessing in-situ mechanical property is important in the case of cladding material owing to its dimensional characteristic. Optimal test method for assessing sodium compatibility of the cladding tube can be proposed that pressurized creep test under the controlled liquid sodium environment.

  4. Measurement of Nucleate Pool Boiling Heat Transfer Limit using Fuel Cladding Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young; Shin, Chang Hwan; Oh, Dong Seok; Chun, Tae Hyun; In, Wang Kee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Zircaloy has been widely used as a fuel cladding material of light water reactor for more than three decades because it has a lower neutron absorption cross section and cracking rate. Recently, HANA-6 has been developed in KAERI (Korea Atomic Energy Research Institute) as the advanced fuel cladding for high burn-up fuel. Generally, under the normal and accident operating conditions of a nuclear reactor, the nuclear fuel cladding of zirconium based alloys undergoes the surface change, and the oxide layer can be formed. In such a case, the previous CHF correlations should be assessed and examined using the experimental results for not a fresh zircaloy surface but an oxidized one, to predict and examine the thermal margin and safety of a nuclear reactor core. Therefore, the experimental data using the oxidized zircaloy surface need to be provided quantitatively. In this paper, the CHF in saturated water pool boiling is measured and discussed using the specimens of zircaloy-4, HANA-6, and oxidized zircaloy-4 in high temperature air environment. The CHF of zircaloy-4, HANA-6, and oxidized surface was tested. Zircaloy-4 and HANA-6 had a similar CHF performance. This is because both are the zirconium based alloys, and appear the almost same water contact angle. On the other hands, the oxidized specimen became to be higher CHF than plain zircaloy-4 and HANA-6 specimens, due to smaller water contact angle (i. e., good hydrophilicity of specimen). The Kandlikar's (2001) correlation reasonably predicted the present experimental data.

  5. The state of the art report on the development of advanced nuclear fuel cladding tube

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Yong; Jeong, Yong Hwan; Park, Sang Yoon; Lee, Myung Ho; Baek, Jong Hyuk; Nam, Cheol; Choi, Byung Kwon

    2001-04-01

    Since the operating conditions of modern PWR trend toward long-term operation, high burn-up, high coolant temperature and high pH, the need to develop a new advanced nuclear fuel cladding as an alternative to Zircaloy-4 increased. To overcome this problem, a number of researches to develop a advanced nuclear fuel cladding tube with superior corrosion resistance and creep resistance have been performed in many advanced nations in the field of nuclear power. Especially, some advanced cladding tubes are already confirmed to have an excellent in-pile properties from the test results in commercial reactor. Also in Korea, KAERI has been researching extensively to develop a high burn-up nuclear fuel cladding Zr alloy since 1990. To design new alloys, it is necessary to study the state of the art on the development of advanced alloys in other countries. In this report, as a part of development of advanced Zr alloy, we studied the state of the art on the development of ZIRLO in U.S.A., E635 in Russia, M5 in France, and MDA and NDA in Japan, which will be applied as basic data to develop an advanced Zr alloy.

  6. Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

    2004-12-14

    Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for

  7. Mechanical modelling of transient- to- failure SFR fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Feria, F.; Herranz, L. E.

    2014-07-01

    The response of Sodium Fast Reactor (SFR) fuel rods to transient accident conditions is an important safety concern. During transients the cladding strain caused by the stress due to pellet cladding mechanical interaction (PCMI) can lead to failure. Due to the fact that SFR fuel rods are commonly clad with strengthened material made of stainless steel (SS), cladding is usually treated as an elastic-perfectly-plastic material. However, viscoplastic behaviour can contribute to mechanical strain at high temperature (> 1000 K). (Author)

  8. High temperature nanoindentation hardness and Young's modulus measurement in a neutron-irradiated fuel cladding material

    Science.gov (United States)

    Kese, K.; Olsson, P. A. T.; Alvarez Holston, A.-M.; Broitman, E.

    2017-04-01

    Nanoindentation, in combination with scanning probe microscopy, has been used to measure the hardness and Young's modulus in the hydride and matrix of a high burn-up neutron-irradiated Zircaloy-2 cladding material in the temperature range 25-300 °C. The matrix hardness was found to decrease only slightly with increasing temperature while the hydride hardness was essentially constant within the temperature range. Young's modulus decreased with increasing temperature for both the hydride and the matrix of the high burn-up fuel cladding material. The hydride Young's modulus and hardness were higher than those of the matrix in the temperature range.

  9. Fabrication and measurement of hoop strength of SiC triplex tube for nuclear fuel cladding applications

    Science.gov (United States)

    Kim, Daejong; Lee, Hyun-Geun; Park, Ji Yeon; Kim, Weon-Ju

    2015-03-01

    The SiC ceramics are under investigation for the fuel cladding in the light water nuclear reactors because of its excellent high temperature strength and corrosion resistance against hot steam under the severe accident conditions. In this study, the SiC triplex tubes consisting of a SiC inner layer, a SiC/PyC/SiC intermediate layer, and a SiC outer layer were fabricated by the chemical vapor processes. The hoop strength and fracture behaviors of the SiC triplex tube were investigated. The SiC triplex tubes fabricated at the high ratio of H2/MTS had a quite high average strength with a relatively small standard deviation. The hoop strength of the composite tubes tends to increase with the volume fraction of the reinforced fibers. The highest fiber volume fraction was obtained using Tyranno SA3-0.8k with the dense winding patterns such as bamboo-like mosaic pattern, which resulted in the high hoop strength compared to other fibers of Tyranno SA3-1.6k and Hi-Nicalon Type S. Hoop strength also increased slightly as the winding angle increased from 45° to 65°. Fracture behaviors of the SiC triplex tube were investigated via the observation of microstructure of the failed samples.

  10. Fabrication and measurement of hoop strength of SiC triplex tube for nuclear fuel cladding applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejong, E-mail: dkim@kaeri.re.kr; Lee, Hyun-Geun; Park, Ji Yeon; Kim, Weon-Ju

    2015-03-15

    The SiC ceramics are under investigation for the fuel cladding in the light water nuclear reactors because of its excellent high temperature strength and corrosion resistance against hot steam under the severe accident conditions. In this study, the SiC triplex tubes consisting of a SiC inner layer, a SiC/PyC/SiC intermediate layer, and a SiC outer layer were fabricated by the chemical vapor processes. The hoop strength and fracture behaviors of the SiC triplex tube were investigated. The SiC triplex tubes fabricated at the high ratio of H{sub 2}/MTS had a quite high average strength with a relatively small standard deviation. The hoop strength of the composite tubes tends to increase with the volume fraction of the reinforced fibers. The highest fiber volume fraction was obtained using Tyranno SA3-0.8k with the dense winding patterns such as bamboo-like mosaic pattern, which resulted in the high hoop strength compared to other fibers of Tyranno SA3-1.6k and Hi-Nicalon Type S. Hoop strength also increased slightly as the winding angle increased from 45° to 65°. Fracture behaviors of the SiC triplex tube were investigated via the observation of microstructure of the failed samples.

  11. Synthesis of the Novel MAX Phases for the Future Nuclear Fuel Cladding and Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Seung Hyeok [Kyunghee Univ., Yongin (Korea, Republic of); Kim, Taehee; Lee, Taegyu; Ryu, H. J. [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    With these properties, the MAX phases are expected to be used for the Accident Tolerant Fuel (ATF) cladding and oxidation/corrosion resistance materials. Especially, the MAX phase can be used for the Gen-IV, SFR and HTGR, component materials which have to possess the thermal and corrosion resistance. The zirconium has been used to the nuclear industry for fuel cladding because of the small thermal neutron cross-section. Zr-based MAX phase was discovered by group Lapauw et al. They observed the Zr{sub 2}AlC and Zr{sub 3}AlC{sub 2} with the X-ray diffraction (XRD) patterns and backscattered electron detector. Fabrication of the Zr-containing MAX phase was investigated for nuclear fuel cladding and structural materials applications. A MAX phase with the Zr{sub 3}AlC{sub 2} structure was synthesized by spark plasma sintering of a powder mixture targeting (Zr{sub 0.5}Cr{sub 0.5}){sub 4}AlC{sub 3}. The formation of MAX phases was confirmed by XRD and EDS of sintered samples. In the future work, the electron probe micro analyzer (EPMA) and transmission electron microscopy (TEM) are required to certain analyze the elements composition and formation of the MAX phase.

  12. High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nelson, Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parkison, Adam [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2013-12-23

    The Fuel Cycle Research and Development (FCRD) program’s Advanced Fuels Campaign has initiated a multifold effort aimed at facilitating development of accident tolerant fuels in order to overcome the inherent shortcomings of light water reactor (LWR) fuels when exposed to beyond design basis accident conditions. The campaign has invested in development of experimental infrastructure within the Department of Energy complex capable of chronicling the performance of a wide range of concepts under prototypic accident conditions. This report summarizes progress made at Oak Ridge National Laboratory (ORNL) and Los Alamos National Laboratory (LANL) in FY13 toward these goals. Alternative fuel cladding materials to Zircaloy for accident tolerance and a significantly extended safety margin requires oxidation resistance to steam or steam-H2 environments at ≥1200°C for short times. At ORNL, prior work focused attention on SiC, FeCr and FeCrAl as the most promising candidates for further development. Also, it was observed that elevated pressure and H2 additions had minor effects on alloy steam oxidation resistance, thus, 1 bar steam was adequate for screening potential candidates. Commercial Fe-20Cr-5Al alloys remain protective up to 1475°C in steam and CVD SiC up to 1700°C in steam. Alloy development has focused on Fe-Cr-Mn-Si-Y and Fe-Cr-Al-Y alloys with the aluminaforming alloys showing more promise. At 1200°C, ferritic binary Fe-Cr alloys required ≥25% Cr to be protective for this application. With minor alloy additions to Fe-Cr, more than 20%Cr was still required, which makes the alloy susceptible to α’ embrittlement. Based on current results, a Fe-15Cr-5Al-Y composition was selected for initial tube fabrication and welding for irradiation experiments in FY14. Evaluations of chemical vapor deposited (CVD) SiC were conducted up to 1700°C in steam. The reaction of H2O with the alumina reaction tube at 1700°C resulted in Al(OH)3

  13. Microstructure stability of candidate stainless steels for Gen-IV SCWR fuel cladding application

    Science.gov (United States)

    Li, Jian; Zheng, W.; Penttilä, S.; Liu, P.; Woo, O. T.; Guzonas, D.

    2014-11-01

    In the past few years, significant progress has been made in materials selection for Gen-IV SCWR fuel cladding applications. Current studies indicate that austenite stainless steels such as 310H are promising candidates for in-core applications. Alloys in this group are promising for their corrosion resistance, SCC resistance, high temperature mechanical properties and creep resistance at temperatures up to 700 °C. However, one under-studied area of this alloy is the long-term microstructure stability under the proposed reactor operating condition. Unstable microstructure not only results in embrittlement but also has the potential to reduce their resistance to corrosion or stress-corrosion cracking. In this study, stainless steels 310H and 304H were tested for their SCWR corrosion resistance and microstructure stability.

  14. Characterization of SiC-SiC composites for accident tolerant fuel cladding

    Science.gov (United States)

    Deck, C. P.; Jacobsen, G. M.; Sheeder, J.; Gutierrez, O.; Zhang, J.; Stone, J.; Khalifa, H. E.; Back, C. A.

    2015-11-01

    Silicon carbide (SiC) is being investigated for accident tolerant fuel cladding applications due to its high temperature strength, exceptional stability under irradiation, and reduced oxidation compared to Zircaloy under accident conditions. An engineered cladding design combining monolithic SiC and SiC-SiC composite layers could offer a tough, hermetic structure to provide improved performance and safety, with a failure rate comparable to current Zircaloy cladding. Modeling and design efforts require a thorough understanding of the properties and structure of SiC-based cladding. Furthermore, both fabrication and characterization of long, thin-walled SiC-SiC tubes to meet application requirements are challenging. In this work, mechanical and thermal properties of unirradiated, as-fabricated SiC-based cladding structures were measured, and permeability and dimensional control were assessed. In order to account for the tubular geometry of the cladding designs, development and modification of several characterization methods were required.

  15. FABRICATION AND MATERIAL ISSUES FOR THE APPLICATION OF SiC COMPOSITES TO LWR FUEL CLADDING

    Directory of Open Access Journals (Sweden)

    WEON-JU KIM

    2013-08-01

    Full Text Available The fabrication methods and requirements of the fiber, interphase, and matrix of nuclear grade SiCf/SiC composites are briefly reviewed. A CVI-processed SiCf/SiC composite with a PyC or (PyC-SiCn interphase utilizing Hi-Nicalon Type S or Tyranno SA3 fiber is currently the best combination in terms of the irradiation performance. We also describe important material issues for the application of SiC composites to LWR fuel cladding. The kinetics of the SiC corrosion under LWR conditions needs to be clarified to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In addition, the development of end-plug joining technology and fission products retention capability of the ceramic composite tube would be key challenges for the successful application of SiC composite cladding.

  16. Development of a used fuel cladding damage model incorporating circumferential and radial hydride responses

    Science.gov (United States)

    Chen, Qiushi; Ostien, Jakob T.; Hansen, Glen

    2014-04-01

    At the completion of the fuel drying process, used fuel Zry4 cladding typically exhibits a significant population of δ-hydride inclusions. These inclusions are in the form of small platelets that are generally oriented both circumferentially and radially within the cladding material. There is concern that radially-oriented hydride inclusions may weaken the cladding material and lead to issues during used fuel storage and transportation processes. A high fidelity model of the mechanical behavior of hydrides has utility in both designing fuel cladding to be more resistant to this hydride-induced weakening and also in suggesting modifications to drying, storage, and transport operations to reduce the impact of hydride formation and/or the avoidance of loading scenarios that could overly stress the radial inclusions. We develop a mechanical model for the Zry4-hydride system that, given a particular morphology of hydride inclusions, allows the calculation of the response of the hydrided cladding under various loading scenarios. The model treats the Zry4 matrix material as J2 elastoplastic, and treats the hydrides as platelets oriented in predefined directions (e.g., circumferentially and radially). The model is hosted by the Albany analysis framework, where a finite element approximation of the weak form of the cladding boundary value problem is solved using a preconditioned Newton-Krylov approach. Instead of forming the required system Jacobian operator directly or approximating its action with a differencing operation, Albany leverages the Trilinos Sacado package to form the Jacobian via automatic differentiation. We present results that describe the performance of the model in comparison with as-fabricated Zry4 as well as HB Robinson fuel cladding. Further, we also present performance results that demonstrate the efficacy of the overall solution method employed to host the model.

  17. Development of a used fuel cladding damage model incorporating circumferential and radial hydride responses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qiushi, E-mail: qiushi@clemson.edu [Glenn Department of Civil Engineering, Clemson University, Clemson, SC 29634 (United States); Ostien, Jakob T., E-mail: jtostie@sandia.gov [Mechanics of Materials Dept. 8256, Sandia National Laboratories, P.O. Box 969, Livermore, CA 94551-0969 (United States); Hansen, Glen, E-mail: gahanse@sandia.gov [Computational Multiphysics Dept. 1443, Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185-1321 (United States)

    2014-04-01

    At the completion of the fuel drying process, used fuel Zry4 cladding typically exhibits a significant population of δ-hydride inclusions. These inclusions are in the form of small platelets that are generally oriented both circumferentially and radially within the cladding material. There is concern that radially-oriented hydride inclusions may weaken the cladding material and lead to issues during used fuel storage and transportation processes. A high fidelity model of the mechanical behavior of hydrides has utility in both designing fuel cladding to be more resistant to this hydride-induced weakening and also in suggesting modifications to drying, storage, and transport operations to reduce the impact of hydride formation and/or the avoidance of loading scenarios that could overly stress the radial inclusions. We develop a mechanical model for the Zry4-hydride system that, given a particular morphology of hydride inclusions, allows the calculation of the response of the hydrided cladding under various loading scenarios. The model treats the Zry4 matrix material as J{sub 2} elastoplastic, and treats the hydrides as platelets oriented in predefined directions (e.g., circumferentially and radially). The model is hosted by the Albany analysis framework, where a finite element approximation of the weak form of the cladding boundary value problem is solved using a preconditioned Newton–Krylov approach. Instead of forming the required system Jacobian operator directly or approximating its action with a differencing operation, Albany leverages the Trilinos Sacado package to form the Jacobian via automatic differentiation. We present results that describe the performance of the model in comparison with as-fabricated Zry4 as well as HB Robinson fuel cladding. Further, we also present performance results that demonstrate the efficacy of the overall solution method employed to host the model.

  18. Patent Analysis of Ferritic/Martensitic Steels for the Fuel Cladding in Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong Hyuk; Kim, Sung Ho; Kim, Tae Kyu; Kim, Woo Gon; Jang, Jin Sung; Kim, Dae Whan; Han, Chang Hee; Lee, Chan Bock

    2007-09-15

    The Korean, Japanese, U.S. and European patents related to the ferritic/martensitic steels were systematically surveyed to evaluate their patent status, which would be applicable to the fuel cladding materials for the Sodium-cooled Fast Reactor (SFR). From the surveys, totally 38 patents were finally selected for the quantitative and qualitative analysis. Among them, 28 patents (74%) were processed by Japanese companies and Sumitomo Metal industries Ltd. was top-ranked in the number (9) of priority patents. On the basis of these surveys, most patents could be applicable to the fuel cladding materials for SFR and, especially, some useful patents as the cladding were registered by the Russian and the Korean.

  19. Corrosion of the AlFeNi alloy used for the fuel cladding in the Jules Horowitz research reactor

    Science.gov (United States)

    Wintergerst, M.; Dacheux, N.; Datcharry, F.; Herms, E.; Kapusta, B.

    2009-09-01

    The AlFeNi aluminium alloy (1 wt% Fe, 1 wt% Ni, 1 wt% Mg) is expected to be used as nuclear fuel cladding for the Jules Horowitz experimental reactor. To guarantee a safe behaviour of the fuel, a good understanding of the fuel clad corrosion mechanisms is required. In this field, the experimental characterization of the selected alloy was performed. Then experimental studies of the aluminium alloy corrosion product obtained in autoclaves have shown an oxide film composed of two layers. This duplex structure results from a mixed growth mechanism: an anionic growth to develop the inner oxide and a cationic diffusion parallel to a dissolution-precipitation process to form the outer zone. Dynamic experiments at 70 °C have demonstrated that a solid diffusion step controls the release kinetic. Then post-irradiation exams performed on irradiated fuel plates were used to investigate the effects of the irradiation on the corrosion behaviour in the reactor core.

  20. Patent Analysis of Ferritic/Martensitic Steels for the Fuel Cladding in Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong Hyuk; Kim, Sung Ho; Kim, Tae Kyu; Kim, Woo Gon; Jang, Jin Sung; Kim, Dae Whan; Han, Chang Hee; Lee, Chan Bock

    2007-09-15

    The Korean, Japanese, U.S. and European patents related to the ferritic/martensitic steels were systematically surveyed to evaluate their patent status, which would be applicable to the fuel cladding materials for the Sodium-cooled Fast Reactor (SFR). From the surveys, totally 38 patents were finally selected for the quantitative and qualitative analysis. Among them, 28 patents (74%) were processed by Japanese companies and Sumitomo Metal industries Ltd. was top-ranked in the number (9) of priority patents. On the basis of these surveys, most patents could be applicable to the fuel cladding materials for SFR and, especially, some useful patents as the cladding were registered by the Russian and the Korean.

  1. Optimization of N18 Zirconium Alloy for Fuel Cladding of Water Reactors

    Institute of Scientific and Technical Information of China (English)

    B.X. Zhou; M. Y. Yao; Z.K. Li; X.M. Wang; J. Zhoua; C.S. Long; Q. Liu; B.F. Luan

    2012-01-01

    In order to optimize the microstructure and composition of N18 zirconium alloy (Zr-1Sn-0.35Nb-0.35Fe-0.1Cr, in mass fraction, %), which was developed in China in 1990s, the effect of microstructure and composition variation on the corrosion resistance of the N18 alloy has been investigated. The autoclave corrosion tests were carried out in super heated steam at 400 ~C/10.3 MPa, in deionized water or lithiated water with 0.01 mol/L LiOH at 360 ~C/18.6 MPa. The exposure time lasted for 300-550 days according to the test temperature. The results show that the microstructure with a fine and uniform distribution of second phase particles (SPPs), and the decrease of Sn content from 1% (in mass fraction, the same as follows) to 0.8% are of benefit to improving the corrosion resistance; It is detrimental to the corrosion resistance if no Cr addition. The addition of Nb content with upper limit (0.35%) is beneficial to improving the corrosion resistance. The addition of Cu less than 0.1% shows no remarkable influence upon the corrosion resistance for N18 alloy. Comparing the corrosion resistance of the optimized N18 with other commercial zirconium alloys, such as Zircaloy-4, ZIRLO, E635 and Ell0, the former shows superior corrosion resistance in all autoclave testing conditions mentioned above. Although the data of the corrosion resistance as fuel cladding for high burn-up has not been obtained yet, it is believed that the optimized N18 alloy is promising for the candidate of fuel cladding materials as high burn-up fuel assemblies. Based on the theory that the microstructural evolution of oxide layer during corrosion process will affect the corrosion resistance of zirconium alloys, the improvement of corrosion resistance of the N18 alloy by obtaining the microstructure with nano-size and uniform distribution of SPPs, and by decreasing the content of Sn and maintaining the content of Cr is discussed.

  2. Galvanic corrosion of Mg-Zr fuel cladding and steel immobilized in Portland cement and geopolymer at early ages

    Science.gov (United States)

    Rooses, Adrien; Lambertin, David; Chartier, David; Frizon, Fabien

    2013-04-01

    Galvanic corrosion behaviour of Mg-Zr alloy fuel cladding and steel has been studied in Ordinary Portland cement and Na-geopolymer. Portland cements implied the worse magnesium corrosion performances due to the negative effects of cement hydrates, grinding agents and gypsum on the galvanic corrosion. Galvanic corrosion in Na-geopolymer paste remains very low. Silicates and fluoride from the geopolymer activation solution significantly improve the corrosion resistance of the magnesium alloy while coupling with a cathode.

  3. Cold Spray Coating Technique with FeCrAl Alloy Powder for Developing Accident Tolerant Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Jun; Kim, Hyun Gil; Park, Jeong Yong; Jung, Yang Il; Park, Jung Hwan; Koo, Yang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Various approaches to enhance safety have been suggested, replacing current Zr-based alloys for fuel cladding with advanced materials exhibiting lower oxidation rates can be a basic solution. Many advanced materials such as FeCrAl alloys; Mn+1AXn, (MAX) phases, where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA, or groups 13 and 14) element and X is either carbon or nitrogen; Mo; and SiC are being considered as possible candidates. Among the proposed fuel cladding substitutes, Fe-based alloys are one of the most promising candidates owing to their excellent formability, high strength, and oxidation resistance at high temperature. In this work, the ATF technology concept of Fe-based alloy coating on the existing Zr-alloy cladding was considered and results on the optimization study for fabrication of coated tube samples were described. Result obtained from high temperature oxidation test under steam environment at 1200 .deg. C indicates that FeCrAl alloy coated Zr metal matrix may maintain its integrity during LOCA. This means that accident tolerance of FeCrAl alloy coated Zr cladding sample had been greatly improved compared to that of existing Zr-based alloy fuel cladding.

  4. Current status of materials development of nuclear fuel cladding tubes for light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zhengang, E-mail: duan_zg@imr.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Yang, Huilong [Department of Nuclear Engineering, School of Engineering, The University of Tokyo, Nakagun, Ibaraki 319-1188 (Japan); Satoh, Yuhki [Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Murakami, Kenta; Kano, Sho; Zhao, Zishou; Shen, Jingjie [Department of Nuclear Engineering, School of Engineering, The University of Tokyo, Nakagun, Ibaraki 319-1188 (Japan); Abe, Hiroaki, E-mail: abe.hiroaki@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering, School of Engineering, The University of Tokyo, Nakagun, Ibaraki 319-1188 (Japan)

    2017-05-15

    Zirconium-based (Zr-based) alloys have been widely used as materials for the key components in light water reactors (LWRs), such as fuel claddings which suffer from waterside corrosion, hydrogen uptakes and strength loss at elevated temperature, especially during accident scenarios like the lost-of-coolant accident (LOCA). For the purpose of providing a safer, nuclear leakage resistant and economically viable LWRs, three general approaches have been proposed so far to develop the accident tolerant fuel (ATF) claddings: optimization of metallurgical composition and processing of Zr-based alloys, coatings on existing Zr-based alloys and replacement of current Zr-based alloys. In this manuscript, an attempt has been made to systematically present the historic development of Zr-based cladding, including the impacts of alloying elements on the material properties. Subsequently, the research investigations on coating layer on the surface of Zr-based claddings, mainly referring coating materials and fabrication methods, have been broadly reviewed. The last section of this review provides the introduction to alternative materials (Non-Zr) to Zr-based alloys for LWRs, such as advanced steels, Mo-based, and SiC-based materials.

  5. Evaluation of zinc addition on fuel cladding corrosion at the Halden test reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kolstad, E.; Symons, W.J.; Bryhn-Integrigtsen, K.; Oberlaender, B.C.

    1996-08-01

    Experimental studies have shown that addition of zinc to a PWR environment reduces the general corrosion rates of materials in the primary system and delays the initiation of primary water stress corrosion cracking (PWSCC) in Alloy 600. In order to provide an early warning of any potential adverse effects on the fuel cladding, corrosion studies were initiated at the Halden test reactor. These tests were carried out in a PWR rig inserted in the Halden reactor core. The rig simulated thermal hydraulic and coolant conditions typical of a MR. It had two flow channels where the fuel rod segments were exposed to the coolant under irradiation flux. Selected pre-characterized rodlets with fresh and pre-irradiated standard and low-tin Zircaloy-4 material were irradiated for three cycles. First cycle lasted for 110 effective full power days (EFPDs), the second for 95 EFPDs and the last 62 EFPDs. The cladding corrosion behavior was monitored by initial, interim and final oxide thickness measurements by eddy current lift-off probe. Crud sampling was performed in both channels after cycle 1 and 2. Destructive post-irradiation examinations (PIE) of two rodlets, irradiated during cycle 1 and 2, have also been completed at the conclusion of the in-pile testing. This report presents the results on oxide thickness measurements, irradiation history and water chemistry data, and the PIE.

  6. Estimation of ring tensile properties of steam oxidized Zircaloy-4 fuel cladding under simulated LOCA condition

    Science.gov (United States)

    Shriwastaw, R. S.; Sawarn, Tapan K.; Banerjee, Suparna; Rath, B. N.; Dubey, J. S.; Kumar, Sunil; Singh, J. L.; Bhasin, Vivek

    2017-09-01

    The present study involves the estimation of ring tensile properties of Indian Pressurised Heavy Water Reactor (IPHWR) fuel cladding made of Zircaloy-4, subjected to experiments under a simulated loss-of-coolant-accident (LOCA) condition. Isothermal steam oxidation experiments were conducted on clad tube specimens at temperatures ranging from 900 to 1200 °C at an interval of 50 °C for different soaking periods with subsequent quenching in water at ambient temperature. The specimens, which survived quenching, were then subjected to ambient temperature ring tension test (RTT). The microstructure was correlated with the mechanical properties. The yield strength (YS) and ultimate tensile strength (UTS) increased initially with rise in oxidation temperature and time duration but then decreased with further increase in oxidation. Ductility is adversely affected with rising oxidation temperature and longer holding time. A higher fraction of load bearing phase and lower oxygen content in it ensures higher residual ductility. Cladding shows almost zero ductility behavior in RIT when load bearing phase fraction is less than 0.72 and its average oxygen concentration is greater than 0.58 wt%.

  7. Modeling and simulation of hydrogen behavior in Zircaloy-4 fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Jason D. Hales; Various

    2014-09-01

    As a result of corrosion during normal operation in nuclear reactors, hydrogen can enter the zirconium-alloy fuel cladding and precipitate as brittle hydride platelets, which can severely degrade the cladding ductility. Under a heterogeneous temperature distribution, hydrides tend to accumulate in the colder areas, creating local spots of degraded cladding that can favor crack initiation. Therefore, an estimation of the local hydride distribution is necessary to help predict the risk of cladding failure. The hydride distribution is governed by three competing phenomena. Hydrogen in solid solution diffuses under a concentration gradient due to Fick’s law and under a temperature gradient due to the Soret effect. Precipitation of the hydride platelets occurs once the hydrogen solubility limit is reached. A model of these phenomena was implemented in the 3D fuel performance code BISON in order to calculate the hydrogen distribution for arbitrary geometries, such as a nuclear fuel rod, and is now available for BISON users. Simulations have been performed on simple geometries to validate the model and its implementation. The simulations predict that before precipitation occurs, hydrogen tends to accumulate in the colder spots due to the Soret effect. Once the solubility limit is reached, hydrogen precipitates and forms a rim close to the outer edge of the cladding. The simulations also predict that the reactor shut down has little effect on already precipitated hydrides but causes the remaining hydrogen to precipitate homogeneously into hydrides.

  8. Modeling and simulation of hydrogen behavior in Zircaloy-4 fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Courty, Olivier, E-mail: o.courty@gmail.com [Pennsylvania State University, 45 Bd Gouvion Saint Cyr, 75017 Paris (France); Motta, Arthur T., E-mail: atm2@psu.edu [Department of Mechanical and Nuclear Engineering, 227 Reber Building, Penn State University, University Park, PA 16802 (United States); Hales, Jason D., E-mail: jason.hales@inl.gov [Fuels Modeling and Simulation Department, Idaho National Laboratory (United States)

    2014-09-15

    As a result of corrosion during normal operation in nuclear reactors, hydrogen can enter the zirconium-alloy fuel cladding and precipitate as brittle hydride platelets, which can severely degrade the cladding ductility. Under a heterogeneous temperature distribution, hydrides tend to accumulate in the colder areas, creating local spots of degraded cladding that can favor crack initiation. Therefore, an estimation of the local hydride distribution is necessary to help predict the risk of cladding failure. The hydride distribution is governed by three competing phenomena. Hydrogen in solid solution diffuses under a concentration gradient due to Fick’s law and under a temperature gradient due to the Soret effect. Precipitation of the hydride platelets occurs once the hydrogen solubility limit is reached. A model of these phenomena was implemented in the 3D fuel performance code BISON in order to calculate the hydrogen distribution for arbitrary geometries, such as a nuclear fuel rod, and is now available for BISON users. Simulations have been performed on simple geometries to validate the model and its implementation. The simulations predict that before precipitation occurs, hydrogen tends to accumulate in the colder spots due to the Soret effect. Once the solubility limit is reached, hydrogen precipitates and forms a rim close to the outer edge of the cladding. The simulations also predict that the reactor shut down has little effect on already precipitated hydrides but causes the remaining hydrogen to precipitate homogeneously into hydrides.

  9. Obtention of the constitutive equation of hydride blisters in fuel cladding from nanoindentation tests

    Science.gov (United States)

    Martin Rengel, M. A.; Gomez, F. J.; Rico, A.; Ruiz-Hervias, J.; Rodriguez, J.

    2017-04-01

    It is well known that the presence of hydrides in nuclear fuel cladding may reduce its mechanical and fracture properties. This situation may be worsened as a consequence of the formation of hydride blisters. These blisters are zones with an extremely high hydrogen concentration and they are usually associated to the oxide spalling which may occur at the outer surface of the cladding. In this work, a method which allows us to reproduce, in a reliable way, hydride blisters in the laboratory has been devised. Depth-sensing indentation tests with a spherical indenter were conducted on a hydride blister produced in the laboratory with the aim of measuring its mechanical behaviour. The plastic stress-strain curve of the hydride blister was calculated for first time by combining depth-sensing indentation tests results with an iterative algorithm using finite element simulations. The algorithm employed reduces, in each iteration, the differences between the numerical and the experimental results by modifying the stress-strain curve. In this way, an almost perfect adjustment of the experimental data was achieved after several iterations. The calculation of the constitutive equation of the blister from nanoindentation tests, may involve a lack of uniqueness. To evaluate it, a method based on the optimization of parameters of analytical equations has been proposed in this paper. An estimation of the error which involves this method is also provided.

  10. RF Plasma Torch System for Metal Matrix Composite Production in Nuclear Fuel Cladding

    Science.gov (United States)

    Holik, Eddie, III

    2007-10-01

    For the first time in 30 years, plans are afoot to build new fission power plants in the US. It is timely to develop technology that could improve the safety and efficiency of new reactors. A program of development for advanced fuel cycles and Generation IV reactors is underway. The path to greater efficiency is to increase the core operating temperature. That places particular challenges to the cladding tubes that contain the fission fuel. A promising material for this purpose is a metal matrix composite (MMC) in which ceramic fibers are bonded within a high-strength steel matrix, much like fiberglass. Current MMC technology lacks the ability to effectively bond traditional high-temperature alloys to ceramic strands. The purpose of this project is to design an rf plasma torch system to use titanium as a buffer between the ceramic fibers and the refractory outer material. The design and methods of using an rf plasma torch to produce a non-equilibrium phase reaction to bond together the MMC will be discussed. The effects of having a long lived fuel cladding in the design of future reactors will also be discussed.

  11. Advanced Steels for Accident Tolerant Fuel Cladding in Current Light Water Reactors

    Science.gov (United States)

    Rebak, Raul B.

    After the March 2011 Fukushima events, the U.S. Congress directed the Department of Energy (DOE) to focus efforts on the development of fuel cladding materials with enhanced accident tolerance. In comparison with the stand-ard UO2-Zirconium based system, the new fuels need to tolerate loss of active cooling in the core for a considerably longer time period while maintaining or improving the fuel performance during normal operation conditions. Advanced steels such as iron-chromium-aluminum (FeCrAl) alloys are being investigated for degradation behavior both under normal operation conditions in high temperature water (e.g. 288°C) and under accident conditions for reaction with steam up to 1400°C. Commercial and experimental alloys were tested for several periods of time in 100% superheated steam from 800°C to 1475°C. Results show that FeCrAl alloys significantly outperform the resistance in steam of the current zirconium alloys.

  12. High temperature oxidation of fuel cladding candidate materials in steam-hydrogen environments

    Science.gov (United States)

    Pint, B. A.; Terrani, K. A.; Brady, M. P.; Cheng, T.; Keiser, J. R.

    2013-09-01

    Alternative fuel cladding materials to Zr alloys are being investigated for enhanced accident tolerance, which specifically involves oxidation resistance to steam or steam-H2 environments at ⩾1200 °C for short times. Based on a comparison of a range of commercial and model alloys, conventional austenitic steels do not have sufficient oxidation resistance with only ˜18Cr-10Ni. Higher alloyed type 310 stainless steel is protective but Ni is not a desirable alloy addition for this application. Results at 1350 °C indicated that FeCrAl alloys and CVD SiC remain oxidation resistant in steam. At 1200 °C, high (⩾25% Cr) ferritic alloys appear to be good candidates for this application. Higher pressures (up to 20.7 bar) and H2 additions appeared to have a limited effect on the oxidation behavior of the most oxidation resistant alloys, but higher pressures accelerated the maximum metal loss for less oxidation resistant steels and less metal loss was observed for type 317 L tubing in a H2-50%H2O environment at 10.3 bar compared to 100% H2O.

  13. Modeling and simulation of hydrogen behavior in Zircaloy-4 fuel cladding

    Science.gov (United States)

    Courty, Olivier; Motta, Arthur T.; Hales, Jason D.

    2014-09-01

    As a result of corrosion during normal operation in nuclear reactors, hydrogen can enter the zirconium-alloy fuel cladding and precipitate as brittle hydride platelets, which can severely degrade the cladding ductility. Under a heterogeneous temperature distribution, hydrides tend to accumulate in the colder areas, creating local spots of degraded cladding that can favor crack initiation. Therefore, an estimation of the local hydride distribution is necessary to help predict the risk of cladding failure. The hydride distribution is governed by three competing phenomena. Hydrogen in solid solution diffuses under a concentration gradient due to Fick's law and under a temperature gradient due to the Soret effect. Precipitation of the hydride platelets occurs once the hydrogen solubility limit is reached. A model of these phenomena was implemented in the 3D fuel performance code BISON in order to calculate the hydrogen distribution for arbitrary geometries, such as a nuclear fuel rod, and is now available for BISON users. Simulations have been performed on simple geometries to validate the model and its implementation. The simulations predict that before precipitation occurs, hydrogen tends to accumulate in the colder spots due to the Soret effect. Once the solubility limit is reached, hydrogen precipitates and forms a rim close to the outer edge of the cladding. The simulations also predict that the reactor shut down has little effect on already precipitated hydrides but causes the remaining hydrogen to precipitate homogeneously into hydrides.

  14. Revisiting the method to obtain the mechanical properties of hydrided fuel cladding in the hoop direction

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rengel, M.A., E-mail: mamartin@mater.upm.es [Departamento de Ciencia de Materiales, UPM, ETSI Caminos, Canales y Puertos, Profesor Aranguren s/n, E-28040 Madrid (Spain); Gomez Sanchez, F.J., E-mail: javier.gomez@amsimulation.com [Advanced Material Simulation, S.L (Spain); Ruiz-Hervias, J.; Caballero, L.; Valiente, A. [Departamento de Ciencia de Materiales, UPM, ETSI Caminos, Canales y Puertos, Profesor Aranguren s/n, E-28040 Madrid (Spain)

    2012-10-15

    The method reported in the literature to calculate the stress-strain curve of nuclear fuel cladding from ring tensile test is revisited in this paper and a new alternative is presented. In the former method, two universal curves are introduced under the assumption of small strain. In this paper it is shown that these curves are not universal, but material-dependent if geometric nonlinearity is taken into account. The new method is valid beyond small strains, takes geometric nonlinearity into consideration and does not need universal curves. The stress-strain curves in the hoop direction are determined by combining numerical calculations with experimental results in a convergent loop. To this end, ring tensile tests were performed in unirradiated hydrogen-charged samples. The agreement among the simulations and the experimental results is excellent for the range of concentrations tested (up to 2000 wppm hydrogen). The calculated stress-strain curves show that the mechanical properties do not depend strongly on the hydrogen concentration, and that no noticeable strain hardening occurs. However, ductility decreases with the hydrogen concentration, especially beyond 500 wppm hydrogen. The fractographic results indicate that as-received samples fail in a ductile fashion, whereas quasicleavage is observed in the hydrogen-charged samples.

  15. Characterization of Zircaloy-4 tubing procured for fuel cladding research programs

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, R.H. (comp.)

    1976-06-14

    A quantity of Zircaloy-4 tubing (10.92 mm outside diameter by 0.635 mm wall thickness) was purchased specifically for use in a number of related fuel cladding research programs sponsored by the Division of Reactor Safety Research, Nuclear Regulatory Commission (NRC/RSR). Identical tubing (produced simultaneously and from the same ingot) was purchased concurrently by the Electric Power Research Institute (EPRI) for use in similar research programs sponsored by that organization. In this way, source variability and prior fabrication history were eliminated as parameters, thus permitting direct comparison (as far as as-received material properties are concerned) of experimental results from the different programs. The tubing is representative of current reactor technology. Consecutive serial numbers assigned to each tube identify the sequence of the individual tubes through the final tube wall reduction operation. The report presented documents the procurement activities, provides a convenient reference source of manufacturer's data and tubing distribution to the various users, and presents some preliminary characterization data. The latter have been obtained routinely in various research programs and are not complete. Although the number of analyses, tests, and/or examinations performed to date are insufficient to draw statistically valid conclusions with regard to material characterization, the data are expected to be representative of the as-received tubing. It is anticipated that additional characterizations will be performed and reported routinely by the various research programs that use the tubing.

  16. Interactive chemical reactivity exploration.

    Science.gov (United States)

    Haag, Moritz P; Vaucher, Alain C; Bosson, Maël; Redon, Stéphane; Reiher, Markus

    2014-10-20

    Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the samson programming environment. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Interactive Chemical Reactivity Exploration

    CERN Document Server

    Haag, Moritz P; Bosson, Mael; Redon, Stephane; Reiher, Markus

    2014-01-01

    Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force-feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the Samson programming environment.

  18. Boiling performance and material robustness of modified surfaces with multi scale structures for fuel cladding development

    Energy Technology Data Exchange (ETDEWEB)

    Jo, HangJin; Kim, Jin Man [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Yeom, Hwasung [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States); Lee, Gi Cheol [Department of Mechanical Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Kiyofumi, Moriyama; Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Sridharan, Kumar; Corradini, Michael [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States)

    2015-09-15

    Highlights: • We improved boiling performance and material robustness using surface modification. • We combined micro/millimeter post structures and nanoparticles with heat treatments. • Compactly-arranged micrometer posts had improved boiling performance. • CHF increased significantly due to capillary pumping by the deposited NP layers. • Sintering procedure increased mechanical strength of the NP coating surface. - Abstract: By regulating the geometrical characteristics of multi-scale structures and by adopting heat treatment for protective layer of nanoparticles (NPs), we improved critical heat flux (CHF), boiling heat transfer (BHT), and mechanical robustness of the modified surface. We fabricated 1-mm and 100-μm post structures and deposited NPs on the structured surface as a nano-scale structured layer and protective layer at the same time, then evaluated the CHF and BHT and material robustness of the modified surfaces. On the structured surfaces without NPs, the surface with compactly-arranged micrometer posts had improved CHF (118%) and BHT (41%). On the surface with structures on which NPs had been deposited, CHF increased significantly (172%) due to capillary pumping by the deposited NP layers. The heat treatment improved robustness of coating layer in comparison to the one of before heat treatment. In particular, low-temperature sintering increased the hardness of the modified surface by 140%. The increased mechanical strength of the NP coating is attributed to reduction in coating porosity during sintering. The combination of micrometer posts structures and sintered NP coating can increase the safety, efficiency and reliability of advanced nuclear fuel cladding.

  19. Effect of the Boron and Nitrogen on precipitation behavior in modified 9Cr steel for SFR fuel cladding after aging

    Energy Technology Data Exchange (ETDEWEB)

    Jeog, Eun-Hee; Kim, Young Do [Hanyang University, Seoul (Korea, Republic of); Kim, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Ferritic-martensitic steels are being considered as an attractive candidate material for a fuel cladding of a SFR due to their low expansion coefficients, high thermal conductivities and excellent irradiation resistances against void swelling. Because of its superior dimensional stability against fast neutron irradiation, Ferritic-martensitic steel of 9Cr and 12Cr steels are preferable to utilize in the fuel cladding of an SFR in KAERI. The soluble boron reduces the coarsening rate of M{sub 23}C{sub 6} carbides along boundaries near prior austenite grain boundaries during creep, enhancing the boundary and sub-boundary hardening for up to long times. The enhancement of boundary and sub-boundary hardening retards the onset of acceleration creep, which decreases the minimum creep rate and improves the creep life. It has been reported that the excess addition of boron and nitrogen promotes the formation of boron nitrides during normalizing heat treatment, which significantly reduces soluble B and N concentrations and offsets the benefit due to boron and nitrogen. In this study, comparison of the microstructure and mechanical properties on SFR fuel cladding steel with different B and N contents after aging were carried out. The addition of B stabilizes the M{sub 23}C{sub 6}, hence the coarsening of M{sub 23}C{sub 6} was not observed in alloy 1 after 7000 hours aging. The size distribution of an alloy 2 was not largely changed with aging time, and this phenomena would be caused by an addition of nitrogen, by stabilize the nitride precipitates such as MX and M{sub 2}X.

  20. Neutronic Analysis on Potential Accident Tolerant Fuel-Cladding Combination U3Si2-FeCrAl

    OpenAIRE

    Shengli Chen; Cenxi Yuan

    2017-01-01

    Neutronic performance is investigated for a potential accident tolerant fuel (ATF), which consists of U3Si2 fuel and FeCrAl cladding. In comparison with current UO2-Zr system, FeCrAl has a better oxidation resistance but a larger thermal neutron absorption cross section. U3Si2 has a higher thermal conductivity and a higher uranium density, which can compensate the reactivity suppressed by FeCrAl. Based on neutronic investigations, a possible U3Si2-FeCrAl fuel-cladding system is taken into con...

  1. Advanced ODS FeCrAl alloys for accident-tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N [ORNL; Unocic, Kinga A [ORNL; Hoelzer, David T [ORNL; Pint, Bruce A [ORNL

    2014-09-01

    ODS FeCrAl alloys are being developed with optimum composition and properties for accident tolerant fuel cladding. Two oxide dispersion strengthened (ODS) Fe-15Cr-5Al+Y2O3 alloys were fabricated by ball milling and extrusion of gas atomized metallic powder mixed with Y2O3 powder. To assess the impact of Mo on the alloy mechanical properties, one alloy contained 1%Mo. The hardness and tensile properties of the two alloys were close and higher than the values reported for fine grain PM2000 alloy. This is likely due to the combination of a very fine grain structure and the presence of nano oxide precipitates. The nano oxide dispersion was however not sufficient to prevent grain boundary sliding at 800 C and the creep properties of the alloys were similar or only slightly superior to fine grain PM2000 alloy. Both alloys formed a protective alumina scale at 1200 C in air and steam and the mass gain curves were similar to curves generated with 12Cr-5Al+Y2O3 (+Hf or Zr) ODS alloys fabricated for a different project. To estimate the maximum temperature limit of use for the two alloys in steam, ramp tests at a rate of 5 C/min were carried out in steam. Like other ODS alloys, the two alloys showed a significant increase of the mas gains at T~ 1380 C compared with ~1480 C for wrought alloys of similar composition. The beneficial effect of Yttrium for wrought FeCrAl does not seem effective for most ODS FeCrAl alloys. Characterization of the hardness of annealed specimens revealed that the microstructure of the two alloys was not stable above 1000 C. Concurrent radiation results suggested that Cr levels <15wt% are desirable and the creep and oxidation results from the 12Cr ODS alloys indicate that a lower Cr, high strength ODS alloy with a higher maximum use temperature could be achieved.

  2. Ferritic Alloys as Accident Tolerant Fuel Cladding Material for Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, Raul B. [General Electric Global Research, Schnectady, NY (United States)

    2014-09-30

    The objective of the GE project is to demonstrate that advanced steels such as iron-chromium-aluminum (FeCrAl) alloys could be used as accident tolerant fuel cladding material in commercial light water reactors. The GE project does not include fuel development. Current findings support the concept that a FeCrAl alloy could be used for the cladding of commercial nuclear fuel. The use of this alloy will benefit the public since it is going to make the power generating light water reactors safer. In the Phase 1A of this cost shared project, GE (GRC + GNF) teamed with the University of Michigan, Los Alamos National Laboratory, Brookhaven National Laboratory, Idaho National Laboratory, and Oak Ridge National Laboratory to study the environmental and mechanical behavior of more than eight candidate cladding materials both under normal operation conditions of commercial nuclear reactors and under accident conditions in superheated steam (loss of coolant condition). The main findings are as follows: (1) Under normal operation conditions the candidate alloys (e.g. APMT, Alloy 33) showed excellent resistance to general corrosion, shadow corrosion and to environmentally assisted cracking. APMT also showed resistance to proton irradiation up to 5 dpa. (2) Under accident conditions the selected candidate materials showed several orders of magnitude improvement in the reaction with superheated steam as compared with the current zirconium based alloys. (3) Tube fabrication feasibility studies of FeCrAl alloys are underway. The aim is to obtain a wall thickness that is below 400 µm. (4) A strategy is outlined for the regulatory path approval and for the insertion of a lead fuel assembly in a commercial reactor by 2022. (5) The GE team worked closely with INL to have four rodlets tested in the ATR. GE provided the raw stock for the alloys, the fuel for the rodlets and the cost for fabrication/welding of the rodlets. INL fabricated the rodlets and the caps and welded them to

  3. Development of ODS FeCrAl alloys for accident-tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-18

    FeCrAl alloys are prime candidates for accident-tolerant fuel cladding due to their excellent oxidation resistance up to 1400 C and good mechanical properties at intermediate temperature. Former commercial oxide dispersion strengthened (ODS) FeCrAl alloys such as PM2000 exhibit significantly better tensile strength than wrought FeCrAl alloys, which would alloy for the fabrication of a very thin (~250 m) ODS FeCrAl cladding and limit the neutronic penalty from the replacement of Zr-based alloys by Fe-based alloys. Several Fe-12-Cr-5Al ODS alloys where therefore fabricated by ball milling FeCrAl powders with Y2O3 and additional oxides such as TiO2 or ZrO2. The new Fe-12Cr-5Al ODS alloys showed excellent tensile strength up to 800 C but limited ductility. Good oxidation resistance in steam at 1200 and 1400 C was observed except for one ODS FeCrAl alloy containing Ti. Rolling trials were conducted at 300, 600 C and 800 C to simulate the fabrication of thin tube cladding and a plate thickness of ~0.6mm was reached before the formation of multiple edge cracks. Hardness measurements at different stages of the rolling process, before and after annealing for 1h at 1000 C, showed that a thinner plate thickness could likely be achieved by using a multi-step approach combining warm rolling and high temperature annealing. Finally, new Fe-10-12Cr-5.5-6Al-Z gas atomized powders have been purchased to fabricate the second generation of low-Cr ODS FeCrAl alloys. The main goals are to assess the effect of O, C, N and Zr contents on the ODS FeCrAl microstructure and mechanical properties, and to optimize the fabrication process to improve the ductility of the 2nd gen ODS FeCrAl while maintaining good mechanical strength and oxidation resistance.

  4. Ferritic Alloys as Accident Tolerant Fuel Cladding Material for Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, Raul B. [General Electric Global Research, Schnectady, NY (United States)

    2014-12-30

    The objective of the GE project is to demonstrate that advanced steels such as iron-chromium-aluminum (FeCrAl) alloys could be used as accident tolerant fuel cladding material in commercial light water reactors. The GE project does not include fuel development. Current findings support the concept that a FeCrAl alloy could be used for the cladding of commercial nuclear fuel. The use of this alloy will benefit the public since it is going to make the power generating light water reactors safer. In the Phase 1A of this cost shared project, GE (GRC + GNF) teamed with the University of Michigan, Los Alamos National Laboratory, Brookhaven National Laboratory, Idaho National Laboratory, and Oak Ridge National Laboratory to study the environmental and mechanical behavior of more than eight candidate cladding materials both under normal operation conditions of commercial nuclear reactors and under accident conditions in superheated steam (loss of coolant condition). The main findings are as follows: (1) Under normal operation conditions the candidate alloys (e.g. APMT, Alloy 33) showed excellent resistance to general corrosion, shadow corrosion and to environmentally assisted cracking. APMT also showed resistance to proton irradiation up to 5 dpa. (2) Under accident conditions the selected candidate materials showed several orders of magnitude improvement in the reaction with superheated steam as compared with the current zirconium based alloys. (3) Tube fabrication feasibility studies of FeCrAl alloys are underway. The aim is to obtain a wall thickness that is below 400 µm. (4) A strategy is outlined for the regulatory path approval and for the insertion of a lead fuel assembly in a commercial reactor by 2022. (5) The GE team worked closely with INL to have four rodlets tested in the ATR. GE provided the raw stock for the alloys, the fuel for the rodlets and the cost for fabrication/welding of the rodlets. INL fabricated the rodlets and the caps and welded them to

  5. Obtention of fracture properties of unirradiated fuel cladding from ring compression tests

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rengel, M.A. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos Profesor Aranguren s/n, E-28040 Madrid (Spain); Consejo de Seguridad Nuclear (CSN), Justo Dorado 11, E-28040 Madrid (Spain); Gomez, F.J.; Ruiz-Hervias, J.; Caballero, L.; Valiente, A. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos Profesor Aranguren s/n, E-28040 Madrid (Spain)

    2009-06-15

    Zirconium alloy cladding is used as the first structural barrier to contain the nuclear fuel and the fission products. In addition to its neutron transparency, this material has a good corrosion resistance and remarkable mechanical properties at operational temperatures. Consequently, it is or paramount importance to precisely characterize the mechanical behaviour and fracture properties of irradiated cladding to ensure a safe operation. It is known that the mechanical behaviour of unirradiated zirconium alloy cladding is anisotropic. The elastoplastic response depends on the direction, namely radial, hoop or longitudinal. For this reason, different fracture properties should be expected in each direction. From the various tests employed to characterize the mechanical behaviour along the hoop direction in nuclear fuel cladding, the ring compression test is particularly useful to study material fracture. With this test it is possible to determine the moment when a real crack is formed, due to a sudden decrease in the applied load at a given displacement value. The aim of this research is to determine as precisely as possible the value of the fracture energy from the ring compression test load vs. displacement curves. To this end, a finite element calculation incorporating the cohesive zone model was performed. In this case, the cohesive zone theory is applied in its simplest form. It is considered that the cohesive crack transfers a constant stress until the displacement of this cohesive crack reaches a critical value. At this precise moment a real crack is generated. The properties of the softening curve of the cohesive zone model can be obtained by directly comparing the experimental load vs. displacement records with the finite element calculations. The area under the softening curve is the fracture energy, which is directly related with the material fracture toughness. The experimental data used in this work have been obtained on unirradiated Zirlo cladding

  6. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding

    Science.gov (United States)

    Rico, A.; Martin-Rengel, M. A.; Ruiz-Hervias, J.; Rodriguez, J.; Gomez-Sanchez, F. J.

    2014-09-01

    It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young's modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young's modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.

  7. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Rico, A., E-mail: alvaro.rico@urjc.es [DIMME, Departamento de Tecnología Mecánica, Universidad Rey Juan Carlos, c/Tulipán s/n, E-28933 Móstoles, Madrid (Spain); Martin-Rengel, M.A., E-mail: mamartin@mater.upm.es [Departamento de Ciencia de los Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren SN, E-28040 Madrid (Spain); Ruiz-Hervias, J., E-mail: jesus.ruiz@upm.es [Departamento de Ciencia de los Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren SN, E-28040 Madrid (Spain); Rodriguez, J. [DIMME, Departamento de Tecnología Mecánica, Universidad Rey Juan Carlos, c/Tulipán s/n, E-28933 Móstoles, Madrid (Spain); Gomez-Sanchez, F.J., E-mail: javier.gomez@amsimulation.com [Advanced Material Simulation, S.L, Madrid (Spain)

    2014-09-15

    It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young’s modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young’s modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.

  8. Neutronic Analysis on Potential Accident Tolerant Fuel-Cladding Combination U3Si2-FeCrAl

    Directory of Open Access Journals (Sweden)

    Shengli Chen

    2017-01-01

    Full Text Available Neutronic performance is investigated for a potential accident tolerant fuel (ATF, which consists of U3Si2 fuel and FeCrAl cladding. In comparison with current UO2-Zr system, FeCrAl has a better oxidation resistance but a larger thermal neutron absorption cross section. U3Si2 has a higher thermal conductivity and a higher uranium density, which can compensate the reactivity suppressed by FeCrAl. Based on neutronic investigations, a possible U3Si2-FeCrAl fuel-cladding system is taken into consideration. Fundamental properties of the suggested fuel-cladding combination are investigated in a fuel assembly. These properties include moderator and fuel temperature coefficients, control rods worth, radial power distribution (in a fuel rod, and different void reactivity coefficients. The present work proves that the new combination has less reactivity variation during its service lifetime. Although, compared with the current system, it has a little larger deviation on power distribution and a little less negative temperature coefficient and void reactivity coefficient and its control rods worth is less important, variations of these parameters are less important during the service lifetime of fuel. Hence, U3Si2-FeCrAl system is a potential ATF candidate from a neutronic view.

  9. Development and Experimental Benchmark of Simulations to Predict Used Nuclear Fuel Cladding Temperatures during Drying and Transfer Operations

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, Miles [Univ. of Nevada, Reno, NV (United States)

    2017-03-31

    Radial hydride formation in high-burnup used fuel cladding has the potential to radically reduce its ductility and suitability for long-term storage and eventual transport. To avoid this formation, the maximum post-reactor temperature must remain sufficiently low to limit the cladding hoop stress, and so that hydrogen from the existing circumferential hydrides will not dissolve and become available to re-precipitate into radial hydrides under the slow cooling conditions during drying, transfer and early dry-cask storage. The objective of this research is to develop and experimentallybenchmark computational fluid dynamics simulations of heat transfer in post-pool-storage drying operations, when high-burnup fuel cladding is likely to experience its highest temperature. These benchmarked tools can play a key role in evaluating dry cask storage systems for extended storage of high-burnup fuels and post-storage transportation, including fuel retrievability. The benchmarked tools will be used to aid the design of efficient drying processes, as well as estimate variations of surface temperatures as a means of inferring helium integrity inside the canister or cask. This work will be conducted effectively because the principal investigator has experience developing these types of simulations, and has constructed a test facility that can be used to benchmark them.

  10. High Temperature and Pressure Steam-H2 Interaction with Candidate Advanced LWR Fuel Claddings

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A [ORNL

    2012-08-01

    This report summarizes the work completed to evaluate cladding materials that could serve as improvements to Zircaloy in terms of accident tolerance. This testing involved oxidation resistance to steam or H{sub 2}-50% steam environments at 800-1350 C at 1-20 bar for short times. A selection of conventional alloys, SiC-based ceramics and model alloys were used to explore a wide range of materials options and provide guidance for future materials development work. Typically, the SiC-based ceramic materials, alumina-forming alloys and Fe-Cr alloys with {ge}25% Cr showed the best potential for oxidation resistance at {ge}1200 C. At 1350 C, FeCrAl alloys and SiC remained oxidation resistant in steam. Conventional austenitic steels do not have sufficient oxidation resistance with only {approx}18Cr-10Ni. Higher alloyed type 310 stainless steel is protective but Ni is not a desirable alloy addition for this application and high Cr contents raise concern about {alpha}{prime} formation. Higher pressures (up to 20.7 bar) and H{sub 2} additions appeared to have a limited effect on the oxidation behavior of the most oxidation resistant alloys but higher pressures accelerated the maximum metal loss for less oxidation resistant steels and less metal loss was observed in a H{sub 2}-50%H{sub 2}O environment at 10.3 bar. As some of the results regarding low-alloyed FeCrAl and Fe-Cr alloys were unexpected, further work is needed to fundamentally understand the minimum Cr and Al alloy contents needed for protective behavior in these environments in order to assist in alloy selection and guide alloy development.

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

    Science.gov (United States)

    Chen, Yingzi

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

  12. Evaluation of Tritium Content and Release from Pressurized Water Reactor Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Sharon M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chattin, Marc Rhea [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giaquinto, Joseph [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    It is expected that tritium pretreatment will be required in future reprocessing plants to prevent the release of tritium to the environment (except for long-cooled fuels). To design and operate future reprocessing plants in a safe and environmentally compliant manner, the amount and form of tritium in the used nuclear fuel (UNF) must be understood and quantified. Tritium in light water reactor (LWR) fuel is dispersed between the fuel matrix and the fuel cladding, and some tritium may be in the plenum, probably as tritium labelled water (THO) or T2O. In a standard processing flowsheet, tritium management would be accomplished by treatment of liquid streams within the plant. Pretreating the fuel prior to dissolution to release the tritium into a single off-gas stream could simplify tritium management, so the removal of tritium in the liquid streams throughout the plant may not be required. The fraction of tritium remaining in the cladding may be reduced as a result of tritium pretreatment. Since Zircaloy® cladding makes up roughly 25% by mass of UNF in the United States, processes are being considered to reduce the volume of reprocessing waste for Zircaloy® clad fuel by recovering the zirconium from the cladding for reuse. These recycle processes could release the tritium in the cladding. For Zircaloy-clad fuels from light water reactors, the tritium produced from ternary fission and other sources is expected to be divided between the fuel, where it is generated, and the cladding. It has been previously documented that a fraction of the tritium produced in uranium oxide fuel from LWRs can migrate and become trapped in the cladding. Estimates of the percentage of tritium in the cladding typically range from 0–96%. There is relatively limited data on how the tritium content of the cladding varies with burnup and fuel history (temperature, power, etc.) and how pretreatment impacts its release. To gain a better understanding of how tritium in cladding

  13. New method to calculate the mechanical properties of unirradiated fuel cladding from ring tensile tests

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rengel, M.A. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren s/n, E-28040 Madrid (Spain); Consejo de Seguridad Nuclear (CSN), Justo Dorado 11, E-28040 Madrid (Spain); Gomez, F.J.; Ruiz-Hervias, J.; Caballero, L.; Valiente, A. [Departamento de Ciencia de Materiales, UPM, E.T.S.I. Caminos, Canales y Puertos, Profesor Aranguren s/n, E-28040 Madrid (Spain)

    2009-06-15

    Nuclear fuel cladding is the first barrier used to confine the fuel and the fission products produced during irradiation. Zirconium alloys are used for this purpose due to their remarkable neutron transparency, together with their good mechanical properties at operational temperatures. Consequently, it is very important to be able to characterize the mechanical response of the irradiated cladding. The mechanical behaviour of the material can be modelled as elastoplastic with different stress-strain curves depending on the direction: radial, hoop or longitudinal direction. The ring tensile test has been proposed to determine the mechanical properties of the cladding along the hoop direction. The initial test consisted of applying a force inside the tube, by means of two half cylinders. Later Arsene and Bai [1,2] modified the experimental device to avoid tube bending at the beginning of the test. The same authors proposed a numerical method to obtain the stress-strain curve in the hoop direction from the experimental load versus displacement results and a given friction coefficient between the loading pieces and the sample [3]. This method has been used by different authors [4] with slight modifications. It is based on the existence of two universal curves under small strain hypothesis: the first correlating the hoop strain and the displacement of the loading piece and the second one correlating the hoop stress and the applied load. In this work, a new method to determine the mechanical properties of the cladding from the ring tensile test results is proposed. Non-linear geometry is considered and an iterative procedure is proposed so universal curves are not needed. A stress-strain curve is determined by combining numerical calculations with experimental results in a convergent loop. The two universal curves proposed by Arsene and Bai [3] are substituted by two relationships, one between the equivalent plastic strain in the centre of the specimen ligament and the

  14. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

    Otto, Sijbren; Engberts, Jan B.F.N.

    2003-01-01

    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  15. Hydrophobic interactions and chemical reactivity

    NARCIS (Netherlands)

    Otto, Sijbren; Engberts, Jan B.F.N.

    2003-01-01

    This perspective describes how kinetic studies of organic reactions can be used to increase our understanding of hydrophobic interactions. In turn, our understanding of hydrophobic interactions can be used as a tool to influence chemical reactions.

  16. In-situ Observation of Boiling Dynamics on Fuel Cladding Surface in Non-pressurized Water Using Acoustic Emission Method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kaige; Baek, Seung Heon; Shim, Hee-Sang; Hur, Do Haeng; Lee, Deok Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In the PWR primary coolant system, a phenomenon of axial offset anomaly (AOA) can be caused due to accumulated boron hide out in porous CRUD deposition on the fuel cladding surface. Up to now, the CRUD deposition has been well known to be driven by subcooled nucleate boiling (SNB) on the cladding surface based on large scale experimental work. Therefore, monitoring and evaluation of the SNB-phenomenon is an important approach to study the CRUD deposition. Many attempts have been made to study the SNB and CRUD deposition using thermal hydraulic or model calculation. However, a comprehensive understanding of the SNB during CRUD deposition is still far from being realized. Acoustic emission (AE) technique, as an in-situ nondestructive evaluation (NDE) method, has been widely used to monitor the boiling activity in containers and pipes. Accordingly, this work aimed to investigate the exact AE characteristics of SNB-phenomenon on the fuel cladding surface at atmospheric pressure, with the purpose of providing an experimental groundwork for the AE investigation on SNB in high-temperature pressurized coolant system. In this study, we conducted an in-situ experimental observation of the bubble dynamic of SNB in non-pressurized water at atmospheric pressure using AE method. The AE of heater noise was confirmed to cluster between 8 and 26 khz. Three AE groups were detected during the boiling process in the Snob zones. AE group 1 and 3 seemed to be the results of bubble growth and collapse, while bubble departure from the cladding surface was reasonably associated with an isolated AE group 2.

  17. Oxidation of Zircaloy Fuel Cladding in Water-Cooled Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, Digby; Urquidi-Macdonald, Mirna; Chen, Yingzi; Ai, Jiahe; Park, Pilyeon; Kim, Han-Sang

    2006-12-12

    Our work involved the continued development of the theory of passivity and passivity breakdown, in the form of the Point Defect Model, with emphasis on zirconium and zirconium alloys in reactor coolant environments, the measurement of critically-important parameters, and the development of a code that can be used by reactor operators to actively manage the accumulation of corrosion damage to the fuel cladding and other components in the heat transport circuits in both BWRs and PWRs. In addition, the modified boiling crevice model has been further developed to describe the accumulation of solutes in porous deposits (CRUD) on fuel under boiling (BWRs) and nucleate boiling (PWRs) conditions, in order to accurately describe the environment that is contact with the Zircaloy cladding. In the current report, we have derived expressions for the total steady-state current density and the partial anodic and cathodic current densities to establish a deterministic basis for describing Zircaloy oxidation. The models are “deterministic” because the relevant natural laws are satisfied explicitly, most importantly the conversation of mass and charge and the equivalence of mass and charge (Faraday’s law). Cathodic reactions (oxygen reduction and hydrogen evolution) are also included in the models, because there is evidence that they control the rate of the overall passive film formation process. Under open circuit conditions, the cathodic reactions, which must occur at the same rate as the zirconium oxidation reaction, are instrumental in determining the corrosion potential and hence the thickness of the barrier and outer layers of the passive film. Controlled hydrodynamic methods have been used to measure important parameters in the modified Point Defect Model (PDM), which is now being used to describe the growth and breakdown of the passive film on zirconium and on Zircaloy fuel sheathing in BWRs and PWRs coolant environments. The modified PDMs recognize the existence of a

  18. Chemical thermodynamics of complex systems: fission product behavior in LWR fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Kohli, R.

    1981-03-01

    A detailed thermodynamic assessment has been made of the chemical reactions of fission products in LWR fuel rods. Using recent thermodynamic data and the in-reactor oxygen potential and temperature range of LWRs, equilibrium thermodynamic calculations were performed for the most plausible reactions of the fission products. The emphasis in this model is on the chemistry of cesium and rubidium and their reactions with the fuel, other fission products, and the zircaloy cladding. The model predictions are discussed for their implications in fuel-cladding interactions.

  19. Carbon 14 distribution in irradiated BWR fuel cladding and released carbon 14 after aqueous immersion of 6.5 years

    Energy Technology Data Exchange (ETDEWEB)

    Sakuragi, T. [Radioactive Waste Management Funding and Research Center, Tsukishima 1-15-7, Chuo City, Tokyo, 104-0052 (Japan); Yamashita, Y.; Akagi, M.; Takahashi, R. [TOSHIBA Corporation, Ukishima Cho 4-1, Kawasaki Ward, Kawasaki, 210-0862 (Japan)

    2016-07-01

    Spent fuel cladding which is highly activated and strongly contaminated is expected to be disposed of in an underground repository. A typical activation product in the activated metal waste is carbon 14 ({sup 14}C), which is mainly generated by the {sup 14}N(n,p){sup 14}C reaction and produces a significant exposure dose due to the large inventory, long half-life (5730 years), rapid release rate, and the speciation and consequent migration parameters. In the preliminary Japanese safety case, the release of radionuclides from the metal matrix is regarded as the corrosion-related congruent release, and the cladding oxide layer is regarded as a source of instant release fraction (IRF). In the present work, specific activity of {sup 14}C was measured using an irradiated BWR fuel cladding (Zircaloy-2, average rod burnup of 41.6 GWd/tU) which has an external oxide film having a thickness of 25.3 μm. The {sup 14}C specific activity of the base metal was 1.49*10{sup 4} Bq/g, which in the corresponding burnup is comparable to values in the existing literature, which were obtained from various irradiated claddings. Although the specific activity in oxide was 2.8 times the base metal activity due to the additive generation by the {sup 17}O(n,α){sup 14}C reaction, the {sup 14}C abundance in oxide was less than 10% of total inventory. A static leaching test using the cladding tube was carried out in an air-tight vessel filled with a deoxygenated dilute NaOH solution (pH of 12.5) at room temperature. After 6.5 years, {sup 14}C was found in each leachate fraction of gas phase and dissolved organics and inorganics, the total of which was less than 0.01% of the {sup 14}C inventory of the immersed cladding tube. A simple calculation based on the congruent release with Zircaloy corrosion has suggested that the 96.7% of released {sup 14}C was from the external oxide layer and 3.3% was from the base Zircaloy metal. However, both the {sup 14}C abundance and the low leaching rate

  20. Development and property evaluation of nuclear grade wrought FeCrAl fuel cladding for light water reactors

    Science.gov (United States)

    Yamamoto, Y.; Pint, B. A.; Terrani, K. A.; Field, K. G.; Yang, Y.; Snead, L. L.

    2015-12-01

    Development of nuclear grade, iron-based wrought FeCrAl alloys has been initiated for light water reactor (LWR) fuel cladding to serve as a substitute for zirconium-based alloys with enhanced accident tolerance. Ferritic alloys with sufficient chromium and aluminum additions can exhibit significantly improved oxidation kinetics in high-temperature steam environments when compared to zirconium-based alloys. In the first phase, a set of model FeCrAl alloys containing 10-20Cr, 3-5Al, and 0-0.12Y in weight percent, were prepared by conventional arc-melting and hot-working processes to explore the effect of composition on the properties of FeCrAlY alloys. It was found that the tensile properties were insensitive to the alloy compositions studied; however, the steam oxidation resistance strongly depended on both the chromium and the aluminum contents. The second phase development focused on strengthening Fe-13Cr-5Al with minor alloying additions of molybdenum, niobium, and silicon. Combined with an optimized thermo-mechanical treatment, a thermally stable microstructure was produced with improved tensile properties at temperatures up to 741 °C.

  1. Investigations of Aluminum-Doped Self-Healing Zircaloy Surfaces in Context of Accident-Tolerant Fuel Cladding Research

    Science.gov (United States)

    Carr, James; Vasudevamurthy, Gokul; Snead, Lance; Hinderliter, Brian; Massey, Caleb

    2016-06-01

    We present here some important results investigating aluminum as an effective surface dopant for increased oxidation resistance of zircaloy nuclear fuel cladding. At first, the transport behavior of aluminum into reactor grade zircaloy was studied using simple diffusion couples at temperatures greater than 770 K. The experiments revealed the formation of tens of microns thick graded Zr-Al layers. The activation energy of aluminum in zircaloy was found to be ~175 kJ/mol (~1.8 eV), indicating the high mobility of aluminum in zircaloy. Subsequently, aluminum sputter-coated zircaloy coupons were heat-treated to achieve surface doping and form compositionally graded layers. These coupons were then tested in steam environments at 1073 and 1273 K. The microstructure of the as-fabricated and steam-corroded specimens was compared to those of pure zircaloy control specimens. Analysis of data revealed that aluminum effectively competed with zircaloy for oxygen up until 1073 K blocking oxygen penetration, with no traces of large scale spalling, indicating mechanically stable interfaces and surfaces. At the highest steam test temperatures, aluminum was observed to segregate from the Zr-Al alloy under layers and migrate to the surface forming discrete clusters. Although this is perceived as an extremely desirable phenomenon, in the current experiments, oxygen was observed to penetrate into the zirconium-rich under layers, which could be attributed to formation of surface defects such as cracks in the surface alumina layers.

  2. Deformation behavior of laser welds in high temperature oxidation resistant Fe-Cr-Al alloys for fuel cladding applications

    Science.gov (United States)

    Field, Kevin G.; Gussev, Maxim N.; Yamamoto, Yukinori; Snead, Lance L.

    2014-11-01

    Ferritic-structured Fe-Cr-Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability and post-weld mechanical behavior of three model alloys in a range of Fe-(13-17.5)Cr-(3-4.4)Al (wt.%) with a minor addition of yttrium using modern laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds using sub-sized, flat dog-bone tensile specimens and digital image correlation (DIC) has been carried out to determine the performance of welds as a function of alloy composition. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. For all proposed alloys, laser welding resulted in a defect free weld devoid of cracking or inclusions.

  3. Behavior of an improved Zr fuel cladding with oxidation resistant coating under loss-of-coolant accident conditions

    Science.gov (United States)

    Park, Dong Jun; Kim, Hyun Gil; Jung, Yang Il; Park, Jung Hwan; Yang, Jae Ho; Koo, Yang Hyun

    2016-12-01

    This study investigates protective coatings for improving the high temperature oxidation resistance of Zr fuel claddings for light water nuclear reactors. FeCrAl alloy and Cr layers were deposited onto Zr plates and tubes using cold spraying. For the FeCrAl/Zr system, a Mo layer was introduced between the FeCrAl coating and the Zr matrix to prevent inter-diffusion at high temperatures. Both the FeCrAl and Cr coatings improved the oxidation resistance compared to that of the uncoated Zr alloy when exposed to a steam environment at 1200 °C. The ballooning behavior and mechanical properties of the coated cladding samples were studied under simulated loss-of-coolant accident conditions. The coated samples showed higher burst temperatures, lower circumferential strain, and smaller rupture openings compared to the uncoated Zr. Although 4-point bend tests of the coated samples showed a small increase in the maximum load, ring compression tests of a sectioned sample showed increased ductility.

  4. Evaluation of the effect of B and N on the microstructure of 9Cr-2W steel during an aging treatment for SFR fuel cladding tubes

    Science.gov (United States)

    Jeong, Eun Hee; Park, Sang-Gyu; Kim, Sung Ho; Kim, Young Do

    2015-12-01

    In this study, the microstructure of sodium-cooled fast reactor (SFR) fuel cladding steel with different B and N contents after aging is compared. The addition of nitrogen produces a large quantity of MX precipitates with sizes of 0.1 μm or smaller during the initial thermal treatment process and this contributes to help such precipitates maintain stability without being excessively affected by aging. B is primarily distributed in the grain boundary precipitates and grain interior precipitates in the initial stage. The B distribution is believed to move to the Cr precipitates after 7000 h and to contribute to suppressing the growth of M23C6.

  5. Evaluations of Mo-alloy for light water reactor fuel cladding to enhance accident tolerance

    Directory of Open Access Journals (Sweden)

    Cheng Bo

    2016-01-01

    Full Text Available Molybdenum based alloy is selected as a candidate to enhance tolerance of fuel to severe loss of coolant accidents due to its high melting temperature of ∼2600 °C and ability to maintain sufficient mechanical strength at temperatures exceeding 1200 °C. An outer layer of either a Zr-alloy or Al-containing stainless steel is designed to provide corrosion resistance under normal operation and oxidation resistance in steam exceeding 1000 °C for 24 hours under severe loss of coolant accidents. Due to its higher neutron absorption cross-sections, the Mo-alloy cladding is designed to be less than half the thickness of the current Zr-alloy cladding. A feasibility study has been undertaken to demonstrate (1 fabricability of long, thin wall Mo-alloy tubes, (2 formability of a protective outer coating, (3 weldability of Mo tube to endcaps, (4 corrosion resistance in autoclaves with simulated LWR coolant, (5 oxidation resistance to steam at 1000–1500 °C, and (6 sufficient axial and diametral strength and ductility. High purity Mo as well as Mo + La2O3 ODS alloy have been successfully fabricated into ∼2-meter long tubes for the feasibility study. Preliminary results are encouraging, and hence rodlets with Mo-alloy cladding containing fuel pellets have been under preparation for irradiation at the Advanced Test Reactor (ATR in Idaho National Laboratory. Additional efforts are underway to enhance the Mo cladding mechanical properties via process optimization. Oxidation tests to temperatures up to 1500 °C, and burst and creep tests up to 1000 °C are also underway. In addition, some Mo disks in close contact with UO2 from a previous irradiation program (to >100 GWd/MTU at the Halden Reactor have been subjected to post-irradiation examination to evaluate the chemical compatibility of Mo with irradiated UO2 and fission products. This paper will provide an update on results from the feasibility study and discuss the attributes of the

  6. The Role of X-Ray Diffraction for Analyzing Zr-Sn-Nb-Fe Alloys as Power Reactor Fuel Cladding

    Directory of Open Access Journals (Sweden)

    Sugondo

    2010-08-01

    Full Text Available Synthesis of Zr-1%Nb-1%Sn-1%Fe alloy is undertaken in order to develop fuel cladding alloy at high burn-up. Powder specimens of Zr-Sn-Nb-Fe alloy were prepared and then formed into pellets with a dimension of 10 mm in height 10 mm in diameter using a pressure of 1.2 ton/cm2. The 5 gram green pellets were then melted in an arc furnace crucible under argon atmosphere. The pressure in the furnace was set at 2 psi and the current was 50 A. Afterwards, the ingots were heated at a temperature of 1100°C for 2 hours and subsequently quenched in water. The ingots then underwent annealing at temperatures of 400°C, 500°C, 600°C, 700°C, and 750°C for 2 hours. The specimens were analyzed using X-ray diffraction in order to construct diffractograms. Results of the diffraction patterns were fitted with data from JCPDF (Joint Committee Powder Diffraction File to determine the type of crystals in the elements or substances. The greater the crystallite dimension, the smaller the dislocation density. Agreeable results for hardening or strengthening were obtained at annealing temperatures of 500°C and 700, whereas for softening or residual stress at 600°C and 750°C. The nucleation of the secondary phase precipitate (SPP was favourable at annealing temperatures of 400°C, 500°C, and 700°C. For Zr-1%Nb-1%Sn-1%Fe alloy with annealing temperatures between 400°C to 800°C, precipitates of Fe2Nb, ZrSn2,FeSn, SnZr, NbSn2, Zr0.68Nb0.25Fe0.08, Fe2Nb0.4Zr0.6, Fe37Nb9Zr54, and ω-Zr were observed. Satisfactory precipitate stabilization was achieved at annealing temperature of 800°C, growth of precipitates at temperature between 500°C to 600°C, and minimization of precipitate size at 700°C.

  7. Effect of Heat treatment and Aging Conditions on the Microstructure and Mechanical Properties of HT9 Steel for Fuel Cladding Tube

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Hyeong Min; Kim, Jong Lyeol [Hanyang university, Ansan (Korea, Republic of); Kim, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The fuel cladding tube is the most important safety barrier in a fission nuclear reactor. Thermal creep and void swelling occur by fission gas at high temperature during service time. Ferritic-martensitic steels are being considered attractive candidate materials for a fuel cladding of the SFR owing to their low expansion coefficients, high thermal conductivities and excellent irradiation resistance to void swelling. However, HT9 steel has a problem of a relatively low high temperature strength and low creep strength. To solve this problem, a study was conducted to increase the high temperature strength by changing the intermediate heat treatment step in the fabrication process of ferritic martensitic steel and controlling the microstructure and precipitate within the material. 700-780 .deg. C contributed to the increase in precipitate size, and the decrease in yield stress and hardness. An empirical equation for the mechanical properties of HT9 was suggested as a function of the microstructure and Hollomon-Jaffe tempering parameter. The results show that the size of the carbide and lath increased after aging, whereas the size of the prior austenite grain was not changed. Both the strength and hardness were decreased with aging, and this tendency saturated after 3000 hours of aging.

  8. Examination of the chemical composition of irradiated zirconium based fuel claddings at the metal/oxide interface by TEM

    Science.gov (United States)

    Abolhassani, S.; Bart, G.; Jakob, A.

    2010-04-01

    Detailed post-irradiation examinations have been performed at PSI on three fuel rods with differing cladding materials revealing different corrosion behaviour. The rods had been irradiated for 3-5 cycles at Gösgen nuclear power plant (pressurised water reactor), Switzerland. As zirconium corrosion is proceeding at the metal/oxide interface, extended micro-structural analyses were performed by transmission electron microscopy (TEM), expecting to possibly reveal phenomena explaining the varying corrosion resistance. This paper reports on the distribution of oxygen at the metal/oxide interface examined by energy dispersive X-ray spectroscopy (EDS) in TEM, while other micro-structural investigations have been published earlier [1]. In order to get some statistical confidence in the analyses, three neighbouring TEM samples of each cladding variant were studied. The oxygen concentration profiles of the three alloys (i.e. low-tin Zircaloy-4, Zr2.5%Nb and extra low-tin (Sn 0.56%)) both in the oxide and metal close to the metal/oxide interface are compared. The results of the examinations show the composition of the oxide in the vicinity of the interface to be sub-stoichiometric for all three materials, indicating an oxide layer adjacent to the interface, with diffusion-controlled access of oxygen to the metal/oxide interface. The metallic parts show highest oxygen concentrations at the metal/oxide interface which are reduced towards the bulk metal, pointing towards the expected second diffusion-controlled process leading to α-Zr (O). Based on the experimental results values for the diffusion coefficients in the range of 0.8-6.0 × 10 -20 m 2 s -1 are estimated for the oxygen dissolution process, the diffusion coefficient in Zircaloy-4 being six times higher than for the other two less corroding alloys. This finding is in contradiction with the present assumptions about the corrosion mechanism, and confirms the expected but not so far reported diffusion controlled oxidation of different zirconium alloys. It also points towards a corrosion rate that is at least partly governed by the diffusion coefficient of oxygen in metal that is different for different alloys, unlike what has been assumed till present.

  9. Evaluation of the effect of B and N on the microstructure of 9Cr–2W steel during an aging treatment for SFR fuel cladding tubes

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Eun Hee [Hanyang University, Department Materials Science and Engineering, 222, Wangsimni-ro, Seongdong-gu, Seoul, 133-791 (Korea, Republic of); Park, Sang-Gyu; Kim, Sung Ho [KAERI, Advanced Fuel Development Division, 989-111 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of); Kim, Young Do, E-mail: ydkim1@hanyang.ac.kr [Hanyang University, Department Materials Science and Engineering, 222, Wangsimni-ro, Seongdong-gu, Seoul, 133-791 (Korea, Republic of)

    2015-12-15

    In this study, the microstructure of sodium-cooled fast reactor (SFR) fuel cladding steel with different B and N contents after aging is compared. The addition of nitrogen produces a large quantity of MX precipitates with sizes of 0.1 μm or smaller during the initial thermal treatment process and this contributes to help such precipitates maintain stability without being excessively affected by aging. B is primarily distributed in the grain boundary precipitates and grain interior precipitates in the initial stage. The B distribution is believed to move to the Cr precipitates after 7000 h and to contribute to suppressing the growth of M{sub 23}C{sub 6}.

  10. Chemical Force Microscopy of Chemical and Biological Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Noy, A

    2006-01-02

    Interactions between chemical functionalities define outcomes of the vast majority of important events in chemistry, biology and materials science. Chemical Force Microscopy (CFM)--a technique that uses direct chemical functionalization of AFM probes with specific functionalities--allows researchers to investigate these important interactions directly. We review the basic principles of CFM, some examples of its application, and theoretical models that provide the basis for understanding the experimental results. We also emphasize application of modern kinetic theory of non-covalent interactions strength to the analysis of CFM data.

  11. Complete Numerical Simulation of Subcooled Flow Boiling in the Presence of Thermal and Chemical Interactions

    Energy Technology Data Exchange (ETDEWEB)

    V.K. Dhir

    2003-04-28

    At present, guidelines for fuel cycle designs to prevent axial offset anomalies (AOA) in pressurized water reactor (PWR) cores are based on empirical data from several operating reactors. Although the guidelines provide an ad-hoc solution to the problem, a unified approach based on simultaneous modeling of thermal-hydraulics, chemical, and nuclear interactions with vapor generation at the fuel cladding surface does not exist. As a result, the fuel designs are overly constrained with a resulting economic penalty. The objective of present project is to develop a numerical simulation model supported by laboratory experiments that can be used for fuel cycle design with respect to thermal duty of the fuel to avoid economic penalty, as well as, AOA. At first, two-dimensional numerical simulation of the growth and departure of a bubble in pool boiling with chemical interaction is considered. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, energy, and species concentration. The Level Set method is used to capture the evolving liquid-vapor interface. A dilute aqueous boron solution is considered in the simulation. From numerical simulations, the dynamic change in concentration distribution of boron during the bubble growth shows that the precipitation of boron can occur near the advancing and receding liquid-vapor interface when the ambient boron concentration level is 3,000 ppm by weight. Secondly, a complete three-dimensional numerical simulation of inception, growth and departure of a single bubble subjected to forced flow parallel to the heater surface was developed. Experiments on a flat plate heater with water and with boron dissolved in the water were carried out. The heater was made out of well-polished silicon wafer. Numbers of nucleation sites and their locations were well controlled. Bubble dynamics in great details on an isolated nucleation site were obtained while varying the wall superheat, liquid subcooling

  12. Predicting Drugs Side Effects Based on Chemical-Chemical Interactions and Protein-Chemical Interactions

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2013-01-01

    Full Text Available A drug side effect is an undesirable effect which occurs in addition to the intended therapeutic effect of the drug. The unexpected side effects that many patients suffer from are the major causes of large-scale drug withdrawal. To address the problem, it is highly demanded by pharmaceutical industries to develop computational methods for predicting the side effects of drugs. In this study, a novel computational method was developed to predict the side effects of drug compounds by hybridizing the chemical-chemical and protein-chemical interactions. Compared to most of the previous works, our method can rank the potential side effects for any query drug according to their predicted level of risk. A training dataset and test datasets were constructed from the benchmark dataset that contains 835 drug compounds to evaluate the method. By a jackknife test on the training dataset, the 1st order prediction accuracy was 86.30%, while it was 89.16% on the test dataset. It is expected that the new method may become a useful tool for drug design, and that the findings obtained by hybridizing various interactions in a network system may provide useful insights for conducting in-depth pharmacological research as well, particularly at the level of systems biomedicine.

  13. Supplemental information for a notice of construction for the Fueled Clad Fabrication System, the Radioisotope Power Systems Facility, and the Fuel Assembly Area

    Energy Technology Data Exchange (ETDEWEB)

    1989-08-01

    This ''Notice of Construction'' has been submitted by the US Department of Energy-Richland Operations Office (P.O. Box 550, Richland, Washington 99352), pursuant to WAC 402-80-070, for three new sources of radionuclide emissions at the Hanford Site in Washington State (Figure 1). The three new sources, the Fueled Clad Fabrication System (FCFS) the Radioisotope Power Systems Facility (RPSF) and the Fuel Assembly Area (FAA) will be located in one facility, the Fuels and materials Examination Facility (FMEF) of the 400 Area. The FMEF was originally designed to provide for post- irradiation examination and fabrication of breeder reactor fuels. These FMEF missions were cancelled before the introduction of any fuel materials or any irradiated material. The current plans are to use the facility to fabricate power supplies to be used in space applications and to produce Fast Flux Test Facility (FFTF) fuel and target assemblies. The FCFS and the RPSF will produce materials and assemblies for application in space. The FAA project will produce FFTF fuel and target assemblies. The FCFS and the RPSF will share the same building, stack, and, in certain cases, the same floor space. Given this relationship, to the extent possible, these systems will be dealt with separately. The FAA is a comparatively independent operation though it will share the FMEF complex.

  14. Prevention of significant deterioration permit application for the Fueled Clad Fabrication System, the Radioisotope Power Systems Facility, and the Fuel Assembly Area

    Energy Technology Data Exchange (ETDEWEB)

    1989-08-01

    This New Source Review'' has been submitted by the US Department of Energy-Richland Operations Office (PO Box 550, Richland, Washington 99352), pursuant to WAC 173-403-050 and in compliance with the Department of Ecology Guide to Processing A Prevention Of Significant Deterioration (PSD) Permit'' for three new sources of radionuclide emissions at the Hanford Site in Washington State. The three new sources, the Fueled Clad Fabrication System (FCFS), the Radioisotope Power Systems Facility (RPSF), and the Fuel Assembly Area (FAA), will be located in one facility, the Fuels and Materials Examination Facility (FMEF) of the 400 Area. The FMEF was originally designed to provide for post-irradiation examination and fabrication of breeder reactor fuels. These FMEF missions were cancelled before the introduction of any fuel materials or any irradiated material. The current plans are to use the facility to fabricate power supplies for use in space applications and to produce Fast Flux Test Facility (FFTF) fuel and target assemblies. The FCFS and the RPSF will produce materials and assemblies for application in space. The FAA project will produce FFTF fuel and target assemblies. The FCFS and the RPSF will share the same building, stack, and, in certain cases, the same floor space. Given this relationship, these systems will be dealt with separately to the extent possible. The FAA is a comparatively independent operation though it will share the FMEF complex.

  15. A model to describe the anisotropic viscoplastic mechanical behavior of fresh and irradiated Zircaloy-4 fuel claddings under RIA loading conditions

    Science.gov (United States)

    Le Saux, M.; Besson, J.; Carassou, S.; Poussard, C.; Averty, X.

    2008-08-01

    This paper presents a unified phenomenological model to describe the anisotropic viscoplastic mechanical behavior of cold-worked stress relieved (CWSR) Zircaloy-4 fuel claddings submitted to reactivity initiated accident (RIA) loading conditions. The model relies on a multiplicative viscoplastic formulation and reproduces strain hardening, strain rate sensitivity and plastic anisotropy of the material. It includes temperature, fluence and irradiation conditions dependences within RIA typical ranges. Model parameters have been tuned using axial tensile, hoop tensile and closed-end internal pressurization tests results essentially obtained from the PROMETRA program, dedicated to the study of zirconium alloys under RIA loading conditions. Once calibrated, the model provides a reliable description of the mechanical behavior of the fresh and irradiated (fluence up to 10×1025 nm or burnup up to 64 GWd/tU) material within large temperature (from 20 °C up to 1100 °C) and strain rate ranges (from 3×10-4 s up to 5 s), representative of the RIA spectrum. Finally, the model is used for the finite element analysis of the hoop tensile tests performed within the PROMETRA program.

  16. On the effect of temperature on the threshold stress intensity factor of delayed hydride cracking in light water reactor fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Holston, Anna-MariaAlvarez; Stjarnsater, Johan [Studsvik Nuclear AB, Nykoping (Sweden)

    2017-06-15

    Delayed hydride cracking (DHC) was first observed in pressure tubes in Canadian CANDU reactors. In light water reactors, DHC was not observed until the late 1990s in high-burnup boiling water reactor (BWR) fuel cladding. In recent years, the focus on DHC has resurfaced in light of the increased interest in the cladding integrity during interim conditions. In principle, all spent fuel in the wet pools has sufficient hydrogen content for DHC to operate below 300°C. It is therefore of importance to establish the critical parameters for DHC to operate. This work studies the threshold stress intensity factor (K{sub IH}) to initiate DHC as a function of temperature in Zry-4 for temperatures between 227°C and 315°C. The experimental technique used in this study was the pin-loading testing technique. To determine the K{sub IH}, an unloading method was used where the load was successively reduced in a stepwise manner until no cracking was observed during 24 hours. The results showed that there was moderate temperature behavior at lower temperatures. Around 300°C, there was a sharp increase in K{sub IH} indicating the upper temperature limit for DHC. The value for K{sub IH} at 227°C was determined to be 2.6 ± 0.3 MPa √m.

  17. Evaluation of the interfacial shear strength and residual stress of TiAlN coating on ZIRLO™ fuel cladding using a modified shear-lag model approach

    Science.gov (United States)

    Liu, Y.; Bhamji, I.; Withers, P. J.; Wolfe, D. E.; Motta, A. T.; Preuss, M.

    2015-11-01

    This paper investigates the residual stresses and interfacial shear strength of a TiAlN coating on Zr-Nb-Sn-Fe alloy (ZIRLO™) substrate designed to improve corrosion resistance of fuel cladding used in water-cooled nuclear reactors, both during normal and exceptional conditions, e.g. a loss of coolant event (LOCA). The distribution and maximum value of the interfacial shear strength has been estimated using a modified shear-lag model. The parameters critical to this analysis were determined experimentally. From these input parameters the interfacial shear strength between the TiAlN coating and ZIRLO™ substrate was inferred to be around 120 MPa. It is worth noting that the apparent strength of the coating is high (∼3.4 GPa). However, this is predominantly due to the large compressive residuals stress (3 GPa in compression), which must be overcome for the coating to fail in tension, which happens at a load just 150 MPa in excess of this.

  18. CALCULATION OF STRESS AND DEFORMATION IN FUEL ROD CLADDING DURING PELLET-CLADDING INTERACTION

    Directory of Open Access Journals (Sweden)

    Dávid Halabuk

    2015-12-01

    Full Text Available The elementary parts of every fuel assembly, and thus of the reactor core, are fuel rods. The main function of cladding is hermetic separation of nuclear fuel from coolant. The fuel rod works in very specific and difficult conditions, so there are high requirements on its reliability and safety. During irradiation of fuel rods, a state may occur when fuel pellet and cladding interact. This state is followed by changes of stress and deformations in the fuel cladding. The article is focused on stress and deformation analysis of fuel cladding, where two fuels are compared: a fresh one and a spent one, which is in contact with cladding. The calculations are done for 4 different shapes of fuel pellets. It is possible to evaluate which shape of fuel pellet is the most appropriate in consideration of stress and deformation forming in fuel cladding, axial dilatation of fuel, and radial temperature distribution in the fuel rod, based on the obtained results.

  19. Comments on ""Contact Diffusion Interaction of Materials with Cladding''

    Science.gov (United States)

    Morris, J. F.

    1972-01-01

    A Russian paper by A. A. Babad-Zakhryapina contributes much to the understanding of fuel, clad interactions, and thus to nuclear thermionic technology. In that publication the basic diffusion expression is a simple one. A more general but complicated equation for this mass transport results from the present work. With appropriate assumptions, however, the new relation reduces to Babad-Zakhryapina's version.

  20. Characterizing Molecular Interactions in Chemical Systems.

    Science.gov (United States)

    Günther, David; Boto, Roberto A; Contreras-Garcia, Juila; Piquemal, Jean-Philip; Tierny, Julien

    2014-12-01

    Interactions between atoms have a major influence on the chemical properties of molecular systems. While covalent interactions impose the structural integrity of molecules, noncovalent interactions govern more subtle phenomena such as protein folding, bonding or self assembly. The understanding of these types of interactions is necessary for the interpretation of many biological processes and chemical design tasks. While traditionally the electron density is analyzed to interpret the quantum chemistry of a molecular system, noncovalent interactions are characterized by low electron densities and only slight variations of them--challenging their extraction and characterization. Recently, the signed electron density and the reduced gradient, two scalar fields derived from the electron density, have drawn much attention in quantum chemistry since they enable a qualitative visualization of these interactions even in complex molecular systems and experimental measurements. In this work, we present the first combinatorial algorithm for the automated extraction and characterization of covalent and noncovalent interactions in molecular systems. The proposed algorithm is based on a joint topological analysis of the signed electron density and the reduced gradient. Combining the connectivity information of the critical points of these two scalar fields enables to visualize, enumerate, classify and investigate molecular interactions in a robust manner. Experiments on a variety of molecular systems, from simple dimers to proteins or DNA, demonstrate the ability of our technique to robustly extract these interactions and to reveal their structural relations to the atoms and bonds forming the molecules. For simple systems, our analysis corroborates the observations made by the chemists while it provides new visual and quantitative insights on chemical interactions for larger molecular systems.

  1. Status Report on Irradiation Capsules Designed to Evaluate FeCrAl-UO2 Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-24

    This status report provides the background and current status of a series of irradiation capsules that were designed and are being built to test the interactions between candidate FeCrAl cladding for enhanced accident tolerant applications and prototypical enriched commercial UO2 fuel in a neutron radiation environment. These capsules will test the degree, if any, of fuel cladding chemical interactions (FCCI) between FeCrAl and UO2. The capsules are to be irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory to burn-ups of 10, 30, and 50 GWd/MT with a nominal target temperature at the interfaces between the pellets and clad of 350°C.

  2. Interactive Mathematica Simulations in Chemical Engineering Courses

    Science.gov (United States)

    Falconer, John L.; Nicodemus, Garret D.

    2014-01-01

    Interactive Mathematica simulations with graphical displays of system behavior are an excellent addition to chemical engineering courses. The Manipulate command in Mathematica creates on-screen controls that allow users to change system variables and see the graphical output almost instantaneously. They can be used both in and outside class. More…

  3. Interactive Mathematica Simulations in Chemical Engineering Courses

    Science.gov (United States)

    Falconer, John L.; Nicodemus, Garret D.

    2014-01-01

    Interactive Mathematica simulations with graphical displays of system behavior are an excellent addition to chemical engineering courses. The Manipulate command in Mathematica creates on-screen controls that allow users to change system variables and see the graphical output almost instantaneously. They can be used both in and outside class. More…

  4. Space Vehicle Chemical Interactions and Technologies

    Science.gov (United States)

    2015-05-26

    obtained in experiments at the same laboratory ion beam energies. The TOF spectra of the mass 20 amu ammonia -d3 products , ND3+/D2O+, are similar to...the ion product distribution and absolute charge exchange cross section after collision of xenon ions with ammonia at hyperthermal energies is...AFRL-RV-PS- AFRL-RV-PS- TR-2015-0110 TR-2015-0110 SPACE VEHICLE CHEMICAL INTERACTIONS AND TECHNOLOGIES Benjamin D. Prince and Raymond J

  5. The Use of Chemical-Chemical Interaction and Chemical Structure to Identify New Candidate Chemicals Related to Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available Lung cancer causes over one million deaths every year worldwide. However, prevention and treatment methods for this serious disease are limited. The identification of new chemicals related to lung cancer may aid in disease prevention and the design of more effective treatments. This study employed a weighted network, constructed using chemical-chemical interaction information, to identify new chemicals related to two types of lung cancer: non-small lung cancer and small-cell lung cancer. Then, a randomization test as well as chemical-chemical interaction and chemical structure information were utilized to make further selections. A final analysis of these new chemicals in the context of the current literature indicates that several chemicals are strongly linked to lung cancer.

  6. Chemical reaction due to stronger Ramachandran interaction

    Indian Academy of Sciences (India)

    Andrew Das Arulsamy

    2014-05-01

    The origin of a chemical reaction between two reactant atoms is associated with the activation energy, on the assumption that, high-energy collisions between these atoms, are the ones that overcome the activation energy. Here, we show that a stronger attractive van der Waals (vdW) and electron-ion Coulomb interactions between two polarized atoms are responsible for initiating a chemical reaction, either before or after the collision. We derive this stronger vdW attraction formula exactly using the quasi one-dimensional Drude model within the ionization energy theory and the energy-level spacing renormalization group method. Along the way, we expose the precise physical mechanism responsible for the existence of a stronger vdW interaction for both long and short distances, and also show how to technically avoid the electron-electron Coulomb repulsion between polarized electrons from these two reactant atoms. Finally, we properly and correctly associate the existence of this stronger attraction with Ramachandran’s `normal limits’ (distance shorter than what is allowed by the standard vdW bond) between chemically nonbonded atoms.

  7. Pharmit: interactive exploration of chemical space.

    Science.gov (United States)

    Sunseri, Jocelyn; Koes, David Ryan

    2016-07-08

    Pharmit (http://pharmit.csb.pitt.edu) provides an online, interactive environment for the virtual screening of large compound databases using pharmacophores, molecular shape and energy minimization. Users can import, create and edit virtual screening queries in an interactive browser-based interface. Queries are specified in terms of a pharmacophore, a spatial arrangement of the essential features of an interaction, and molecular shape. Search results can be further ranked and filtered using energy minimization. In addition to a number of pre-built databases of popular compound libraries, users may submit their own compound libraries for screening. Pharmit uses state-of-the-art sub-linear algorithms to provide interactive screening of millions of compounds. Queries typically take a few seconds to a few minutes depending on their complexity. This allows users to iteratively refine their search during a single session. The easy access to large chemical datasets provided by Pharmit simplifies and accelerates structure-based drug design. Pharmit is available under a dual BSD/GPL open-source license.

  8. Discriminative Chemical Patterns: Automatic and Interactive Design.

    Science.gov (United States)

    Bietz, Stefan; Schomburg, Karen T; Hilbig, Matthias; Rarey, Matthias

    2015-08-24

    The classification of molecules with respect to their inhibiting, activating, or toxicological potential constitutes a central aspect in the field of cheminformatics. Often, a discriminative feature is needed to distinguish two different molecule sets. Besides physicochemical properties, substructures and chemical patterns belong to the descriptors most frequently applied for this purpose. As a commonly used example of this descriptor class, SMARTS strings represent a powerful concept for the representation and processing of abstract chemical patterns. While their usage facilitates a convenient way to apply previously derived classification rules on new molecule sets, the manual generation of useful SMARTS patterns remains a complex and time-consuming process. Here, we introduce SMARTSminer, a new algorithm for the automatic derivation of discriminative SMARTS patterns from preclassified molecule sets. Based on a specially adapted subgraph mining algorithm, SMARTSminer identifies structural features that are frequent in only one of the given molecule classes. In comparison to elemental substructures, it also supports the consideration of general and specific SMARTS features. Furthermore, SMARTSminer is integrated into an interactive pattern editor named SMARTSeditor. This allows for an intuitive visualization on the basis of the SMARTSviewer concept as well as interactive adaption and further improvement of the generated patterns. Additionally, a new molecular matching feature provides an immediate feedback on a pattern's matching behavior across the molecule sets. We demonstrate the utility of the SMARTSminer functionality and its integration into the SMARTSeditor software in several different classification scenarios.

  9. Integrity assessment of research reactor fuel cladding and material testing using eddy current inspection; Avaliacao de integridade de revestimentos de combustiveis de reatores de pesquisa e teste de materiais utilizando o ensaio de correntes parasitas

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Donizete Anderson de

    2004-07-01

    A methodology to perform the integrity assessment of research reactors nuclear fuels cladding, such as those installed in IPR-Rl (TRIGA) and IEA-R1 (MTR), using nondestructive electromagnetic inspection (eddy current) is presented. This methodology is constituted by: the development of calibration reference standards, specific for each type of fuel; the development of special test probes; the recommendations for the inspection equipment calibration; the construction of voltage based evaluation curves and the inspection procedures developed for the characterization of detected flaws. The test probes development, specially those designed for the inspection of MTR fuels cladding, which present access difficulties due to the narrow gap between fuel plates (2,89 mm for IEAR-R1), constituted a challenge that demanded the introduction of unusual materials and constructive techniques. The operational performance of the developed resources, as well as the special operative characteristics of the test probes, such as their immunity to adjacent fuel plates interference and electrical resistivity changes of the fuels meat are experimentally demonstrated. The practical applicability of the developed methodology is verified in non radioactive environment, using a dummy MTR fuel element model, similar to an IEA-R1 reactor fuel element, produced and installed in IPEN, Sao Paulo. The efficacy of the proposed methodology was verified by the achieved results. (author)

  10. Chemical thermodynamics of Cs and Te fission product interactions in irradiated LMFBR mixed-oxide fuel pins

    Science.gov (United States)

    Adamson, M. G.; Aitken, E. A.; Lindemer, T. B.

    1985-02-01

    A combination of fuel chemistry modelling and equilibrium thermodynamic calculations has been used to predict the atom ratios of Cs and Te fission products (Cs:Te) that find their way into the fuel-cladding interface region of irradiated stainless steel-clad mixed-oxide fast breeder reactor fuel pins. It has been concluded that the ratio of condensed, chemically-associated Cs and Te in the interface region,Čs:Te, which in turn determines the Te activity, is controlled by an equilibrium reaction between Cs 2Te and the oxide fuel, and that the value of Čs:Te is, depending on fuel 0:M, either equal to or slightly less than 2:1. Since Cs and Te fission products are both implicated as causative agents in FCCI (fission product-assisted inner surface attack of stainless steel cladding) and in FPLME (fission product-assisted liquid metal embrittlement of AISI-Type 316), the observed out-of-pile Cs:Te thresholds for FCCI (4˜:1) and FPLME (2˜:1) have been rationalized in terms of Cs:Te thermochemistry and phase equilibria. Also described in the paper is an updated chemical evolution model for reactive/volatile fission product behavior in irradiated oxide pins.

  11. Chemical thermodynamics of Cs and Te fission product interactions in irradiated LMFBR mixed-oxide fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, M.G.; Aitken, E.A. (General Electric Co., Sunnyvale, CA (USA). Advanced Nuclear Technology Operation)

    1985-02-01

    A combination of fuel chemistry modelling and equilibrium thermodynamic calculations has been used to predict the atom ratios of Cs and Te fission products (Cs:Te) that find their way into the fuel-cladding interface region of irradiated stainless steel-clad mixed-oxide fast breeder reactor fuel pins. It has been concluded that the ratio of condensed, chemically-associated Cs and Te in the interface region, chemical evolution model for reactive/volatile fission product behavior in irradiated oxide pins.

  12. Ultrasonic Inspection for Zirconium Alloy Nuclear Fuel Cladding Tubes%核燃料锆合金包壳管的超声波探伤

    Institute of Scientific and Technical Information of China (English)

    夏健文; 韩承

    2016-01-01

    介绍压水堆核燃料锆合金包壳管(Φ10.0 mm×0.70 mm)的超声波自动探伤方法和工艺,讨论不同长度、宽度、深度、角度的纵向和横向人工缺陷的超声响应结果.通过对检测出缺陷的典型包壳管进行金相解剖,确定缺陷性质和实际尺寸,验证超声探伤结果.针对实际探伤中的问题,考虑质量和成本控制,提出对不同缺陷的验收准则.实践应用表明,现行探伤方法和工艺能检出管材不同位置处10μm级的微小缺陷.但受缺陷的类型、取向的影响,探伤仪检测得到的回波幅度并不能完全真实地反应缺陷的实际大小和性质,需要在实际探伤时针对管材的制造工艺水平采取适当的加严措施,对不同的缺陷加以控制,才能更好地保证核燃料包壳管的质量.%The cladding tube is the main component of the nuclear fuel assembly,and as the first protective barrier,its quality is very important for the safe operation of nuclear power plants.After the completion of cladding tubes,a non-destructive testing is required,in which the ultrasonic inspection is a primary method.This paper introduces the ultrasonic flaw testing method and techniques of the zirconium alloy nuclear fuel cladding tubes for pressurized water reactor (PWR),which used in automatic ultrasonic inspection equipment,and discusses the detector response to the longitudinal and transverse artificial defects of different length,width,depth and angle.Its actual shape and size are measured by metallographic anatomical analysis for some typical defects to confirm the flaw detection results.Consider its quality and cost control,the acceptance rules are proposed for different defects.The application shows that the existing detection method and process can inspect the fine defects about 10μm at different locations of the cladding tube.Due to the influence of the defect type and orientation,the echo amplitude obtained by the detector is not completely true to the

  13. Controlling adsorbate interactions for advanced chemical patterning

    Science.gov (United States)

    Saavedra Garcia, Hector M.

    Molecules designed to have specific interactions were used to influence the structural, physical, and chemical properties of self-assembled monolayers. In the case of 1-adamantanethiolate monolayers, the molecular structure influences lability, enabling alkanethiol molecules in solution to displace the 1-adamantanethiolate monolayers, ultimately leading to complete molecular exchange. The similar Au-S bond environments measured for both n-alkanethiolate and 1-adamantanethiolate monolayers indicate that displacement is not a result of weakened Au-S bonds. Instead, it was hypothesized that the density differences in the two monolayers provide a substantial enthalpic driver, aided by differences in van der Waals forces, ultimately leading to complete displacement of the 1-adamantenthiol molecules. Additionally, it was discovered that displacement occurs via fast insertion of n-dodecanethiolate at the defects in the original 1-adamantanethiolate monolayer, which nucleates an island growth phase and is followed by slow ordering of the n-dodecanethiolate domains into a denser and more crystalline form. Langmuir-based kinetics, which describe alkanethiolate adsorption on bare Au{111}, fail to model this displacement reaction. Instead, a model of perimeter-dependent island growth yields good agreement with kinetic data over a 100-fold variation in n-dodecanethiol concentration. Rescaling the growth rate at each concentration collapses all the data onto a single universal curve, suggesting that displacement is a scale-free process. Exploiting the knowledge gained by studying 1-adamantethiolate monolayer displacement, a reversible molecular resist was developed, in which displacement is controlled via external stimuli. This methodology for the fabrication of controllably displaceable monolayers relies on carboxyl-functionalized self-assembled monolayers and in-situ Fischer esterification. Using an 11-mercaptoundecanoic acid monolayer as a model system, it was shown that in

  14. Human metabolic interactions of environmental chemicals.

    Science.gov (United States)

    Hodgson, Ernest; Rose, Randy L

    2007-01-01

    Investigations utilizing recombinant human xenobiotic-metabolizing enzymes as well as human hepatocytes have revealed a number of interactions not only between different environmental chemicals (ECs) but also between ECs and endogenous metabolites. Organophosphorus insecticides (OPs) are potent inhibitors of the human metabolism of carbaryl, carbofuran, DEET and fipronil, as well as the jet fuel components, nonane and naphthalene. OPs are potent irreversible inhibitors of testosterone metabolism by cytochrome P450 (CYP) 3A4 and of estradiol metabolism by CYP3A4 and CYP1A2. All of these CYP inhibitions are believed to be due to the release of reactive sulfur during CYP-catalyzed oxidative desulfuration. It has also been shown that the esterase(s) responsible for the initial step in permethrin metabolism in human liver is inhibited by both chlorpyrifos oxon and carbaryl. A number of pesticides, including chlorpyrifos, fipronil and permethrin, and the repellent, DEET, have been shown to be inducers of CYP isoforms in human hepatocytes, with fipronil being the most potent. Several agrochemicals, including fipronil and the pyrethroids, permethrin and deltamethrin, show toxicity toward human hepatocytes with fipronil being the most potent in this regard. Endosulfan-alpha, which has shown promise as a model substrate for phenotyping CYP3A4 and CYP2B6 in human liver microsomes, is also an inducer of CYP2B6, acting through the PXR receptor.

  15. Chemical interactions in multimetal/zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sachtler, W.M.H.

    1992-12-21

    Research is proposed on two groups of zeolite based catalysts that contain two transition elements. In one group both metals are fully reduced, in the other group one element is left as a positive ion; it can act as a chemical anchor'', or as a catalyst promoter for the reduced metal. The objective is to explore the potential of such materials for designing superior catalysts for synthesis and conversion of hydrocarbons and other energy carriers. ENDOR, EXAFS, CO-FTIR and TPD will be used to identify the interaction of Mn[sup 2+] ions with Rh[sub n] particles in the same zeolite cage. EXAFS at the Kedge of Fe and Pd, FTIR and Moessbauer spectroscopy will be used to characterize Fe ions and alloyed Fe atoms in PdFe/NaHY. The catalysts will be probed with CO hydrogenation and conversion of hydrocarbons. Methods Which proved successful in our study of Y supported bimetal systems will be applied to identify the state of Pt and Cu in ZSM-5, a catalyst system holding large promise for NO abatement, even in the presence of oxygen.

  16. Diffusional Interaction Between U-10 wt pct Zr and Fe at 903 K, 923 K, and 953 K (630 °C, 650 °C, and 680 °C)

    Science.gov (United States)

    Park, Y.; Huang, K.; Paz y Puente, A.; LEE, H. S.; Sencer, B. H.; Kennedy, J. R.; Sohn, Y. H.

    2015-01-01

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced sodium-cooled fast reactor that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuels with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt pct Zr vs pure Fe diffusion couples were assembled and annealed at temperatures, 903 K, 923 K, and 953 K (630 °C, 650 °C, and 680 °C) for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy, and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, α-U, β-U, Zr-precipitates, χ, ɛ, and λ were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area electron diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of χ, ɛ, and λ-phases. The χ, ɛ, and λ-phases were identified as Pnma(62) Fe(Zr,U), I4/ mcm(140) Fe(Zr,U)2, and P42/ mnm(136) U3(Zr,Fe), respectively.

  17. Diffusional Interaction between U-10 wt.% Zr and Fe at 903K, 923K and 953K (630°C, 650°C, and 680°C)

    Energy Technology Data Exchange (ETDEWEB)

    Park, K Y. [Univ. of Central Florida, Orlando, FL (United States). Advanced Materials Processing and Analysis Ctr.; Huang, K. [Univ. of Central Florida, Orlando, FL (United States). Advanced Materials Processing and Analysis Ctr.; Paz y Puente, A. [Northwestern Univ., Evanston, IL (United States); Lee, H. S. [Kyungpook National Univl, Daegu (Korea, Republic of); Sencer, B. H. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Kennedy, J. R. [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

    2014-04-15

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 903, 923 and 953K for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, α-U, β-U, Zr-precipitates, Χ, ε and λ were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of Χ, ε and λ-phases. The Χ, ε and λ-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)2, and I4/mcm(140) U3(Zr,Fe), respectively.

  18. Rhizosphere chemical dialogues: plant-microbe interactions

    Energy Technology Data Exchange (ETDEWEB)

    Badri, D.V.; van der Lelie, D.; Weir, T. L.; Vivanco, J. M.

    2009-12-01

    Every organism on earth relies on associations with its neighbors to sustain life. For example, plants form associations with neighboring plants, microflora, and microfauna, while humans maintain symbiotic associations with intestinal microbial flora, which is indispensable for nutrient assimilation and development of the innate immune system. Most of these associations are facilitated by chemical cues exchanged between the host and the symbionts. In the rhizosphere, which includes plant roots and the surrounding area of soil influenced by the roots, plants exude chemicals to effectively communicate with their neighboring soil organisms. Here we review the current literature pertaining to the chemical communication that exists between plants and microorganisms and the biological processes they sustain.

  19. Predicting Anatomical Therapeutic Chemical (ATC classification of drugs by integrating chemical-chemical interactions and similarities.

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available The Anatomical Therapeutic Chemical (ATC classification system, recommended by the World Health Organization, categories drugs into different classes according to their therapeutic and chemical characteristics. For a set of query compounds, how can we identify which ATC-class (or classes they belong to? It is an important and challenging problem because the information thus obtained would be quite useful for drug development and utilization. By hybridizing the informations of chemical-chemical interactions and chemical-chemical similarities, a novel method was developed for such purpose. It was observed by the jackknife test on a benchmark dataset of 3,883 drug compounds that the overall success rate achieved by the prediction method was about 73% in identifying the drugs among the following 14 main ATC-classes: (1 alimentary tract and metabolism; (2 blood and blood forming organs; (3 cardiovascular system; (4 dermatologicals; (5 genitourinary system and sex hormones; (6 systemic hormonal preparations, excluding sex hormones and insulins; (7 anti-infectives for systemic use; (8 antineoplastic and immunomodulating agents; (9 musculoskeletal system; (10 nervous system; (11 antiparasitic products, insecticides and repellents; (12 respiratory system; (13 sensory organs; (14 various. Such a success rate is substantially higher than 7% by the random guess. It has not escaped our notice that the current method can be straightforwardly extended to identify the drugs for their 2(nd-level, 3(rd-level, 4(th-level, and 5(th-level ATC-classifications once the statistically significant benchmark data are available for these lower levels.

  20. An Interactive Chemical Equilibrium Solver for the Personal Computer

    OpenAIRE

    Negus, Charles H.

    1997-01-01

    AN INTERACTIVE CHEMICAL EQUILIBRIUM SOLVER FOR THE PERSONAL COMPUTER Charles Hugh Negus Felix J. Pierce, Chairman Mechanical Engineering The Virginia Tech Equilibrium Chemistry (VTEC) code is a keyboard interactive, user friendly, chemical equilibrium solver for use on a personal computer. The code is particularly suitable for a teaching / learning environment. For a set of reactants at a defined thermodynamic state given by a user, the program will select all species...

  1. Interactions between chemical additives and their effects on emulsion separation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, M.; Stewart, A.C.; Davies, G.A.

    1996-12-31

    In offshore production, chemical additives are used to combat various operational problems such as corrosion, scaling, foaming and emulsion formation etc. Although individual chemicals may be found to be effective when used alone, there is no guarantee that they will perform as well when present as part of the complex cocktail of additives in the production fluids entering the primary separator. Little is known about interactions between these chemical additives and their effects on gas/oil/water phase separation. This paper will report results from a multi-national sponsored project with the aim of understanding the ways in which chemical additives interact and their effects on emulsion stability with an ultimate objective of developing a strategy for reduction of the chemical inventory offshore. The chemical additives studied include demulsifiers, corrosion inhibitors, scale inhibitors and antifoamants. Both interfacial tension and surface film pressure measurements have been successfully employed to identify interactions between chemical additives and their synergistic effects. Emulsion stability has been measured through conventional bottle tests. It was found that in most cases corrosion inhibitors increased emulsion stability considerably when present both alone and as part of a binary mixture. Interactions between the corrosion inhibitors and some of the demulsifiers were also observed. In contrast the de-foamant and scale inhibitors had little effect on emulsion stability and in most cases did not interact with the other additives.

  2. Simulation of chemical kinetics in sodium-concrete interactions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Sodium-concrete interaction is a key safety-related issue in safety analysis of liquid metal cooled fast breeder reactors (LMFBRs). The chemical kinetics model is a key component of the sodium-concrete interaction model. Conservation equations integrated in sodium-concrete interaction model cannot be solved without a set of relationships that couple the equations together, and this may be done by the chemical kinetics model. Simultaneously,simulation of chemical kinetics is difficult due to complexity of the mechanism of chemical reactions between sodium and concrete. This paper describes the chemical kinetics simulation under some hypotheses. The chemical kinetics model was integrated with the conservation equations to form a computer code. Penetration depth, penetration rate,hydrogen flux, reaction heat, etc. can be provided by this code. Theoretical models and computational procedure were recounted in detail. Good agreements of an overall transient behavior were obtained in a series of sodium-concrete interaction experiment analysis. Comparison between analytical and experimental results showed that the chemical kinetics model presented in this paper was creditable and reasonable for simulating the sodium-concrete interactions.

  3. Emphasizing the Significance of Electrostatic Interactions in Chemical Bonding

    Science.gov (United States)

    Venkataraman, Bhawani

    2017-01-01

    This paper describes a pedagogical approach to help students understand chemical bonding by emphasizing the importance of electrostatic interactions between atoms. The approach draws on prior studies that have indicated many misconceptions among students in understanding the nature of the chemical bond and energetics associated with bond formation…

  4. Statistically designed experiments to screen chemical mixtures for possible interactions

    NARCIS (Netherlands)

    Groten, J.P.; Tajima, O.; Feron, V.J.; Schoen, E.D.

    1998-01-01

    For the accurate analysis of possible interactive effects of chemicals in a defined mixture, statistical designs are necessary to develop clear and manageable experiments. For instance, factorial designs have been successfully used to detect two-factor interactions. Particularly useful for this purp

  5. Statistically designed experiments to screen chemical mixtures for possible interactions

    NARCIS (Netherlands)

    Groten, J.P.; Tajima, O.; Feron, V.J.; Schoen, E.D.

    1998-01-01

    For the accurate analysis of possible interactive effects of chemicals in a defined mixture, statistical designs are necessary to develop clear and manageable experiments. For instance, factorial designs have been successfully used to detect two-factor interactions. Particularly useful for this purp

  6. Climate-chemical interactions and greenhouse effects of trace gases

    Science.gov (United States)

    Shi, Guang-Yu; Fan, Xiao-Biao

    1994-01-01

    A completely coupled one-dimensional radiative-convective (RC) and photochemical-diffusion (PC) model has been developed recently and used to study the climate-chemical interactions. The importance of radiative-chemical interactions within the troposphere and stratosphere has been examined in some detail. We find that increases of radiatively and/or chemically active trace gases such as CO2, CH4 and N2O have both the direct effects and the indirect effects on climate change by changing the atmospheric O3 profile through their interaction with chemical processes in the atmosphere. It is also found that the climatic effect of ozone depends strongly on its vertical distribution throughout the troposphere and stratosphere, as well on its column amount in the atmosphere.

  7. Evaluation of Chemical Interactions between Small Molecules in the Gas Phase Using Chemical Force Microscopy.

    Science.gov (United States)

    Lee, Jieun; Ju, Soomi; Kim, In Tae; Jung, Sun-Hwa; Min, Sun-Joon; Kim, Chulki; Sim, Sang Jun; Kim, Sang Kyung

    2015-12-04

    Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, we investigated the effect of humidity on the analysis of force-distance curves and the images in lateral force mode. Flat chemical patterns composed of different functional groups were made through micro-contact printing and lateral force mode provided more resolved analysis of the chemical patterns. From the images of 1-octadecanethiol/11-mercapto-1-undecanoic acid patterns, the amine group functionalized tip brought out higher contrast of the patterns than an intact silicon nitride tip owing to the additional chemical interaction between carboxyl and amine groups. For more complex chemical interactions, relative chemical affinities toward specific peptides were assessed on the pattern of 1-octadecanethiol/phenyl-terminated alkanethiol. The lateral image of chemical force microscopy reflected specific preference of a peptide to phenyl group as well as the hydrophobic interaction.

  8. Cumulative risk: toxicity and interactions of physical and chemical stressors.

    Science.gov (United States)

    Rider, Cynthia V; Boekelheide, Kim; Catlin, Natasha; Gordon, Christopher J; Morata, Thais; Selgrade, Maryjane K; Sexton, Kenneth; Simmons, Jane Ellen

    2014-01-01

    Recent efforts to update cumulative risk assessment procedures to incorporate nonchemical stressors ranging from physical to psychosocial reflect increased interest in consideration of the totality of variables affecting human health and the growing desire to develop community-based risk assessment methods. A key roadblock is the uncertainty as to how nonchemical stressors behave in relationship to chemical stressors. Physical stressors offer a reasonable starting place for measuring the effects of nonchemical stressors and their modulation of chemical effects (and vice versa), as they clearly differ from chemical stressors; and "doses" of many physical stressors are more easily quantifiable than those of psychosocial stressors. There is a commonly held belief that virtually nothing is known about the impact of nonchemical stressors on chemically mediated toxicity or the joint impact of coexposure to chemical and nonchemical stressors. Although this is generally true, there are several instances where a substantial body of evidence exists. A workshop titled "Cumulative Risk: Toxicity and Interactions of Physical and Chemical Stressors" held at the 2013 Society of Toxicology Annual Meeting provided a forum for discussion of research addressing the toxicity of physical stressors and what is known about their interactions with chemical stressors, both in terms of exposure and effects. Physical stressors including sunlight, heat, radiation, infectious disease, and noise were discussed in reference to identifying pathways of interaction with chemical stressors, data gaps, and suggestions for future incorporation into cumulative risk assessments.

  9. ;Study of secondary hydriding at high temperature in zirconium based nuclear fuel cladding tubes by coupling information from neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and laser induced breakdown spectroscopy microprobe

    Science.gov (United States)

    Brachet, Jean-Christophe; Hamon, Didier; Le Saux, Matthieu; Vandenberghe, Valérie; Toffolon-Masclet, Caroline; Rouesne, Elodie; Urvoy, Stéphane; Béchade, Jean-Luc; Raepsaet, Caroline; Lacour, Jean-Luc; Bayon, Guy; Ott, Frédéric

    2017-05-01

    This paper gives an overview of a multi-scale experimental study of the secondary hydriding phenomena that can occur in nuclear fuel cladding materials exposed to steam at high temperature (HT) after having burst (loss-of-coolant accident conditions). By coupling information from several facilities, including neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and micro laser induced breakdown spectroscopy, it was possible to map quantitatively, at different scales, the distribution of oxygen and hydrogen within M5™ clad segments having experienced ballooning and burst at HT followed by steam oxidation at 1100 and 1200 °C and final direct water quenching down to room temperature. The results were very reproducible and it was confirmed that internal oxidation and secondary hydriding at HT of a cladding after burst can lead to strong axial and azimuthal gradients of hydrogen and oxygen concentrations, reaching 3000-4000 wt ppm and 1.0-1.2 wt% respectively within the β phase layer for the investigated conditions. Consistent with thermodynamic and kinetics considerations, oxygen diffusion into the prior-β layer was enhanced in the regions highly enriched in hydrogen, where the α(O) phase layer is thinner and the prior-β layer thicker. Finally the induced post-quenching hardening of the prior-β layer was mainly related to the local oxygen enrichment. Hardening directly induced by hydrogen was much less significant.

  10. 建立反应堆燃料元件破损运行判据的思考%A Scheme for Establishing of Criterions for Reactor Safe Operation in Condition of Fuel Clad Failure

    Institute of Scientific and Technical Information of China (English)

    林晓玲

    2013-01-01

    Operation criterions are used to decide if the reactor can continue to work when the fuel clad failure. The method for establish the limits is presented. The tolerated maximum of failure fuel rods for the reactor safety should be calculated by risk analysis. The parameters are determined which can not only reflect the quantity but also be measured directly. The relationship is set up between the amounts with the parameters. The data calculated corresponding to maximum of failure fuel element which the reactor safety can stand are technical limits used to decide if the reactor can work continually.%运行判据是用于判断反应堆燃料元件发生破损时能否继续运行的指标条件,本文提出建立反应堆燃料元件破损运行判据的思路和方法,通过风险分析,确定监督运行最大容许破损数量;研究提出既能反映燃料元件破损数量又可直接监测的指标参量,并建立破损数量与可监测指标参量之间的对应关系;将最大容许破损数量对应的可监测指标参量值作为运行技术判据.

  11. Chemical interactions in multimetal/zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sachtler, W.M.H.

    1992-02-07

    Mechanistic explanations have been found for the migration of atoms and ions through the zeolite channels leading to specific distribution of ions and the metal clusters. In this report, we summarize the state of understanding attained on a number of topics in the area of mono- and multimetal/zeolite systems, to which our recent research has made significant contributions. The following topics are discussed: (1) Formation of isolated metal atoms in sodalite cages; (2) differences of metal/zeolite systems prepared by ion reduction in channels or via isolated atoms; (3) rejuvenation of Pd/NaY and Pd/HY catalysts by oxidative redispersion of the metal; (4) formation of mono- or bimetal particles in zeolites by programmed reductive decomposition of volatile metal complexes; (5) cation-cation interaction as a cause of enhanced reducibility; (6) formation of palladium carbonyl clusters in supercages; (7) enhanced catalytic activity of metal particle-proton complexes for hydrocarbon conversion reactions; (8) stereoselectivity of catalytic reactions due to geometric constraints of particles in cages.

  12. The role of chemical interactions in ion-solid processes

    Energy Technology Data Exchange (ETDEWEB)

    Dodson, B.W.

    1990-01-01

    Computer simulation of low-energy ion-solid processes has greatly broadened in scope in recent years. In particular, realistic descriptions of the ion-solid and solid-solid interactions can now be utilized. The molecular dynamics technique, in which the equations of motion of the interacting atoms are numerically integrated, can now be used to characterize ion-solid interactions in a range of model material systems. Despite practical limitations of this procedure, a number of substantial results have appeared. The available results are examined to investigate the qualitative influence that chemical interactions have on low-energy ion-solid processes. 26 refs., 4 figs.

  13. Chemical-gene interaction networks and causal reasoning for ...

    Science.gov (United States)

    Evaluating the potential human health and ecological risks associated with exposures to complex chemical mixtures in the environment is one of the main challenges of chemical safety assessment and environmental protection. There is a need for approaches that can help to integrate chemical monitoring and biological effects data to evaluate risks associated with chemicals present in the environment. Here, we used prior knowledge about chemical-gene interactions to develop a knowledge assembly model for detected chemicals at five locations near the North Branch and Chisago wastewater treatment plants (WWTP) in the St. Croix River Basin, MN and WI. The assembly model was used to generate hypotheses about the biological impacts of the chemicals at each location. The hypotheses were tested using empirical hepatic gene expression data from fathead minnows exposed for 12 d at each location. Empirical gene expression data were also mapped to the assembly models to evaluate the likelihood of a chemical contributing to the observed biological responses using richness and concordance statistics. The prior knowledge approach was able predict the observed biological pathways impacted at one site but not the other. Atrazine was identified as a potential contributor to the observed gene expression responses at a location upstream of the North Branch WTTP. Four chemicals were identified as contributors to the observed biological responses at the effluent and downstream o

  14. Chemical and biological rhizosphere interactions in low zinc soils

    NARCIS (Netherlands)

    Duffner, A.

    2014-01-01

    Abstract of the PhD thesis entitled “Chemical and biological rhizosphere interactions in low zinc soils” by Andreas Duffner Soil provides ecosystem services critical for life. The availability of micronutrients, such as zinc (Zn), in soils is an essenti

  15. Rapid Identification of Chemical Genetic Interactions in Saccharomyces cerevisiae

    Science.gov (United States)

    Dilworth, David; Nelson, Christopher J.

    2015-01-01

    Determining the mode of action of bioactive chemicals is of interest to a broad range of academic, pharmaceutical, and industrial scientists. Saccharomyces cerevisiae, or budding yeast, is a model eukaryote for which a complete collection of ~6,000 gene deletion mutants and hypomorphic essential gene mutants are commercially available. These collections of mutants can be used to systematically detect chemical-gene interactions, i.e. genes necessary to tolerate a chemical. This information, in turn, reports on the likely mode of action of the compound. Here we describe a protocol for the rapid identification of chemical-genetic interactions in budding yeast. We demonstrate the method using the chemotherapeutic agent 5-fluorouracil (5-FU), which has a well-defined mechanism of action. Our results show that the nuclear TRAMP RNA exosome and DNA repair enzymes are needed for proliferation in the presence of 5-FU, which is consistent with previous microarray based bar-coding chemical genetic approaches and the knowledge that 5-FU adversely affects both RNA and DNA metabolism. The required validation protocols of these high-throughput screens are also described. PMID:25867090

  16. Atom interaction propensities of oxygenated chemical functions in crystal packings

    Directory of Open Access Journals (Sweden)

    Christian Jelsch

    2017-03-01

    Full Text Available The crystal contacts of several families of hydrocarbon compounds substituted with one or several types of oxygenated chemical groups were analyzed statistically using the Hirshfeld surface methodology. The propensity of contacts to occur between two chemical types is described with the contact enrichment descriptor. The systematic large enrichment ratios of some interactions like the O—H...O hydrogen bonds suggests that these contacts are a driving force in the crystal packing formation. The same statement holds for the weaker C—H...O hydrogen bonds in ethers, esters and ketones, in the absence of polar H atoms. The over-represented contacts in crystals of oxygenated hydrocarbons are generally of two types: electrostatic attractions (hydrogen bonds and hydrophobic interactions. While Cl...O interactions are generally avoided, in a minority of chloro-oxygenated hydrocarbons, significant halogen bonding does occur. General tendencies can often be derived for many contact types, but outlier compounds are instructive as they display peculiar or rare features. The methodology also allows the detection of outliers which can be structures with errors. For instance, a significant number of hydroxylated molecules displaying over-represented non-favorable oxygen–oxygen contacts turned out to have wrongly oriented hydroxyl groups. Beyond crystal packings with a single molecule in the asymmetric unit, the behavior of water in monohydrate compounds and of crystals with Z′ = 2 (dimers are also investigated. It was found in several cases that, in the presence of several oxygenated chemical groups, cross-interactions between different chemical groups (e.g. water/alcohols; alcohols/phenols are often favored in the crystal packings. While some trends in accordance with common chemical principles are retrieved, some unexpected results can however appear. For example, in crystals of alcohol–phenol compounds, the strong O—H...O hydrogen bonds between

  17. Chemical nonequilibrium for interacting bosons: Applications to the pion gas

    Science.gov (United States)

    Fernández-Fraile, D.; Gómez Nicola, A.

    2009-09-01

    We consider an interacting pion gas in a stage of the system evolution where thermal but not chemical equilibrium has been reached, i.e., for temperatures between thermal and chemical freeze-out TtherLuscher and Gell-Mann-Oakes-Renner-type relations. We pay special attention to the comparison with the conventional kinetic theory approach in the dilute regime, which allows for a check of consistency of our approach. Several phenomenological applications are discussed, concerning chiral symmetry restoration, freeze-out conditions, and Bose-Einstein pion condensation.

  18. Collagen-curcumin interaction - A physico-chemical study

    Indian Academy of Sciences (India)

    N Nishad Fathima; R Saranya Devi; K B Rekha; Aruna Dhathathreyan

    2009-07-01

    Curcumin is a widely used therapeutic agent with a wide spectrum of biological and physiological applications like wound healing and interacts with the skin protein, collagen. This work reports the effect of curcumin on various physico-chemical properties of collagen. The results suggest that significant changes in viscosity and surface tension occur on collagen interacting with curcumin. Secondary structure analysis using circular dichroism shows that curcumin does not alter the triple helical structure of collagen. Increasing concentration of curcumin resulted in aggregation of the protein. Further, curcumin imparts high level of thermal stability to collagen with shrinkage temperature of collagen increasing from 60 to 90°C.

  19. Interaction behavior between binary xCe-yNd alloy and HT9

    Science.gov (United States)

    Kim, Jun Hwan; Cheon, Jin Sik; Lee, Byoung Oon; Kim, June Hyung

    2016-10-01

    Studies were carried out to investigate the role of Ce and Nd, contained inside metal fuel during reactor operation, and their effect on the Fuel-Cladding Chemical Interaction (FCCI) phenomenon, which limits fuel performance in the Sodium-cooled Fast Reactor (SFR). Binary model alloys of xCe-yNd were manufactured, and then diffusion couple tests with HT9 (12Cr-1MoWV) ferritic-martensitic cladding material were carried out at a temperature of 660 °C for up to 25 h. The results showed that both Ce and Nd reacted with Fe in the cladding material to form an interaction layer. Analysis of the microstructure and reaction kinetics revealed that Fe in the cladding material rapidly migrates into Ce to form eutectic reaction, leaving a Fe depleted zone, in which Ce substitutes. In the case of Nd element, a typical solid-solid diffusion process governed to form a Fe17Nd2 type intermetallic compound. Synergism between Ce and Nd occurred so that the reaction thickness was increased, reaching the maximum reaction thickness in the case of the xCe-yNd alloy, whose composition was nearly 1:1.

  20. Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

    Directory of Open Access Journals (Sweden)

    L. Deguillaume

    2008-07-01

    Full Text Available This paper discusses the influence of primary biological aerosols (PBA on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

  1. Microbiology and atmospheric processes: chemical interactions of Primary Biological Aerosols

    Science.gov (United States)

    Deguillaume, L.; Leriche, M.; Amato, P.; Ariya, P. A.; Delort, A.-M.; Pöschl, U.; Chaumerliac, N.; Bauer, H.; Flossmann, A. I.; Morris, C. E.

    2008-02-01

    This paper discusses the influence of bioaerosols on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that biological matter represents a significant fraction of air particulate matter and hence affects the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of primary biological particles in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

  2. Can the hydrophilicity of functional monomers affect chemical interaction?

    Science.gov (United States)

    Feitosa, V P; Ogliari, F A; Van Meerbeek, B; Watson, T F; Yoshihara, K; Ogliari, A O; Sinhoreti, M A; Correr, A B; Cama, G; Sauro, S

    2014-02-01

    The number of carbon atoms and/or ester/polyether groups in spacer chains may influence the interaction of functional monomers with calcium and dentin. The present study assessed the chemical interaction and bond strength of 5 standard-synthesized phosphoric-acid ester functional monomers with different spacer chain characteristics, by atomic absorption spectroscopy (AAS), ATR-FTIR, thin-film x-ray diffraction (TF-XRD), scanning electron microscopy (SEM), and microtensile bond strength (μTBS). The tested functional monomers were 2-MEP (two-carbon spacer chain), 10-MDP (10-carbon), 12-MDDP (12-carbon), MTEP (more hydrophilic polyether spacer chain), and CAP-P (intermediate hydrophilicity ester spacer). The intensity of monomer-calcium salt formation measured by AAS differed in the order of 12-MDDP=10-MDP>CAP-P>MTEP>2-MEP. FTIR and SEM analyses of monomer-treated dentin surfaces showed resistance to rinsing for all monomer-dentin bonds, except with 2-MEP. TF-XRD confirmed the weaker interaction of 2-MEP. Highest µTBS was observed for 12-MDDP and 10-MDP. A shorter spacer chain (2-MEP) of phosphate functional monomers induced formation of unstable monomer-calcium salts, and lower chemical interaction and dentin bond strength. The presence of ester or ether groups within longer spacer carbon chains (CAP-P and MTEP) may affect the hydrophilicity, μTBS, and also the formation of monomer-calcium salts.

  3. Chemical interactions and configurational disorder in silicate melts

    Directory of Open Access Journals (Sweden)

    G. Ottonello

    2005-06-01

    Full Text Available The Thermodynamics of quasi-chemical and polymeric models are briefly reviewed. It is shown that the two classes are mutually consistent, and that opportune conversion of the existing quasi-chemical parameterization of binary interactions in MO-SiO2 joins to polymeric models may be afforded without substantial loss of precision. It is then shown that polymeric models are extremely useful in deciphering the structural and reactive properties of silicate melts and glasses. They not only allow the Lux-Flood character of the dissolved oxides to be established, but also discriminate subordinate strain energy contributions to the Gibbs free energy of mixing from the dominant chemical interaction terms. This discrimination means that important information on the short-, medium- and long-range periodicity of this class of substances can be retrieved from thermodynamic analysis. Lastly, it is suggested that an important step forward in deciphering the complex topology of the inhomogeneity ranges observed at high SiO2 content can be performed by applying SCMF theory and, particularly, Matsen-Schick spectral analysis, hitherto applied only to rubberlike materials.

  4. Chemical Genetic Dissection of Brassinosteroid-Ethylene Interaction

    Institute of Scientific and Technical Information of China (English)

    Joshua M.Gendron; Asif Haque; Nathan Gendron; Timothy Chang; Tadao Asami; Zhi-Yong Wang

    2008-01-01

    We undertook a chemical genetics screen to identify chemical inhibitors of brassinosteroid (BR) action.From a chemical library of 10,000 small molecules,one compound was found to inhibit hypocotyl length and activate the expression of a BR-repressed reporter gene (CPD::GUS) in Arabidopsis,and it was named brassinopride (BRP).These effects of BRP could be reversed by co-treatment with brassinolide,suggesting that BRP either directly or indirectly inhibits BR biosynthesis.Interestingly,the compound causes exaggerated apical hooks,similar to that caused by ethylene treatment.The BRP-induced apical hook phenotype can be blocked by a chemical inhibitor of ethylene perception or an ethylene-insensitive mutant,suggesting that,in addition to inhibiting BR,BRP activates ethylene response.Analysis of BRP analogs provided clues about structural features important for its effects on two separate targets in the BR and ethylene pathways.Analyses of the responses of various BR and ethylene mutants to BRP,ethylene,and BR treatments revealed modes of cross-talk between ethylene and BR in dark-grown seedlings.Our results suggest that active downstream BR signaling,but not BR synthesis or a BR gradient,is required for ethylene-induced apical hook formation.The BRP-related compounds can be useful tools for manipulating plant growth and studying hormone interactions.

  5. Variational principles in chemical equilibria: Complex chemical systems with interacting subsystems

    CERN Document Server

    Zilbergleyt, B

    2010-01-01

    The goal of the paper is to derive a revised condition of global equilibrium in complex chemical systems as variational principle in formalism of recently developed discrete thermodynamics (DTD) of chemical equilibria. In classical approach the problem of complex equilibrium is solved by minimization of the system Gibbs’ free energy subject to logistic constraints. DTD demands any isolated system to comprise smaller subentities, which individual equilibria are based on the balance of internal and external thermodynamic forces, acting against them. The internal forces are equal to the subsystems thermodynamic affinities, while external forces originate from subsystems mutual interactions. Those interactions impose additional constraints on the mother system Gibbs’ free energy minimum. Basic expression of discrete thermodynamics, being multiplied by subsystems deviations from their “true” thermodynamic equilibria, is naturally identical to d’Alembert’s principle. A thermodynamic ve...

  6. Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, B.F. [The Norwegian Univ. of Science and Technology, Trondheim (Norway)

    1997-12-31

    The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.

  7. Ions in solution basic principles of chemical interactions

    CERN Document Server

    Burgess, J

    1999-01-01

    This outline of the principles and chemical interactions in inorganic solution chemistry delivers a course module in an area of considerable complexity. Problems with solutions and tutorial hints to test comprehension have been added as a feature to check readers' understanding and assist self-study. Exercises and projects are also provided to help readers deepen and extend their knowledge and understanding. Inorganic solution chemistry is treated thoroughly Emphasis is placed upon NMR, UV-VIS, IR Raman spectroscopy, X-ray diffraction, and such topics as acid-base behaviour, stability constants and kinetics.

  8. 船用堆失水事故元件包壳破损温度阈值及气隙释放后果计算研究%Research on Fuel Cladding Failure Temperature Criteria and Gap Release Radioactive Aftereffect for LOCA of Ship Reactor

    Institute of Scientific and Technical Information of China (English)

    张帆; 张彦招; 赵新文; 商学利

    2014-01-01

    针对船用堆特殊安全性要求,对船用堆失水事故包壳破损温度阈值进行研究。摒弃以往的保守假设,采用最佳估算模型,得到合理的温度阈值,并采用M ELCOR程序对典型破口事故下包壳破损份额及气隙释放的放射性后果进行了计算。计算结果为评估舱室剂量、保障运行人员安全提供了依据。%Aiming at the particular safety requirement of ship reactor ,the research on fuel cladding failure temperature criteria for LOCA was carried out .The conservative assumption was abandoned ,the reasonable fuel cladding failure temperature criteria was gained with the best estimate model , and the fraction of failure and gap release radioactive aftereffect were calculated by MELCOR code .The calculation results can give a reference for evaluating cabin dose and ensuring the safety for operators .

  9. Material Selection for Accident Tolerant Fuel Cladding

    Science.gov (United States)

    Pint, B. A.; Terrani, K. A.; Yamamoto, Y.; Snead, L. L.

    2015-09-01

    Alternative cladding materials to Zr-based alloys are being investigated for accident tolerance, which can be defined as >100X improvement (compared to Zr-based alloys) in oxidation resistance to steam or steam-H2 environments at ≥1473 K (1200 °C) for short times. After reviewing a wide range of candidates, current steam oxidation testing is being conducted on Mo, MAX phases, and FeCrAl alloys. Recently reported low-mass losses for Mo in steam at 1073 K (800 °C) could not be reproduced. Both FeCrAl and MAX phase Ti2AlC form a protective alumina scale in steam. However, commercial Ti2AlC that was not single phase, formed a much thicker oxide at 1473 K (1200 °C) in steam and significant TiO2, and therefore, Ti2AlC may be challenging to form as a cladding or a coating. Alloy development for FeCrAl is seeking to maintain its steam oxidation resistance to 1748 K (1475 °C), while reducing its Cr content to minimize susceptibility to irradiation-assisted α' formation. The composition effects and critical limits to retaining protective scale formation at >1673 K (1400 °C) are still being evaluated.

  10. Material Selection for Accident Tolerant Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Snead, Lance Lewis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Alternative cladding materials to Zr-based alloys are being investigated for accident tolerance, which can be defined as > 100X improvement (compared to Zr-based alloys) in oxidation resistance to steam or steam-H2 environments at ≥ 1200°C for short times. After reviewing a wide range of candidates, current steam oxidation testing is being conducted on Mo, MAX phases and FeCrAl alloys. Recently reported low mass losses for Mo in steam at 800°C could not be reproduced. Both FeCrAl and MAX phase Ti2AlC form a protective alumina scale in steam. However, commercial Ti2AlC that was not single phase, formed a much thicker oxide at 1200°C in steam and significant TiO2, and therefore Ti2AlC may be challenging to form as a cladding or a coating. Alloy development for FeCrAl is seeking to maintain its steam oxidation resistance to 1475°C, while reducing its Cr content to minimize susceptibility to irradiation-assisted α´ formation. The composition effects and critical limits to retaining protective scale formation at > 1400°C are still being evaluated.

  11. Modelling the interaction of steroid receptors with endocrine disrupting chemicals.

    Science.gov (United States)

    D'Ursi, Pasqualina; Salvi, Erika; Fossa, Paola; Milanesi, Luciano; Rovida, Ermanna

    2005-12-01

    The organic polychlorinated compounds like dichlorodiphenyltrichloroethane with its metabolites and polychlorinated biphenyls are a class of highly persistent environmental contaminants. They have been recognized to have detrimental health effects both on wildlife and humans acting as endocrine disrupters due to their ability of mimicking the action of the steroid hormones, and thus interfering with hormone response. There are several experimental evidences that they bind and activate human steroid receptors. However, despite the growing concern about the toxicological activity of endocrine disrupters, molecular data of the interaction of these compounds with biological targets are still lacking. We have used a flexible docking approach to characterize the molecular interaction of seven endocrine disrupting chemicals with estrogen, progesterone and androgen receptors in the ligand-binding domain. All ligands docked in the buried hydrophobic cavity corresponding to the hormone steroid pocket. The interaction was characterized by multiple hydrophobic contacts involving a different number of residues facing the binding pocket, depending on ligands orientation. The EDC ligands did not display a unique binding mode, probably due to their lipophilicity and flexibility, which conferred them a great adaptability into the hydrophobic and large binding pocket of steroid receptors. Our results are in agreement with toxicological data on binding and allow to describe a pattern of interactions for a group of ECD to steroid receptors suggesting the requirement of a hydrophobic cavity to accommodate these chlorine carrying compounds. Although the affinity is lower than for hormones, their action can be brought about by a possible synergistic effect.

  12. Biological efficiency of interaction between various radiation and chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Yu, Dong Han; Lee, Byoung Hun [KAERI, Taejon (Korea, Republic of); Petin, Vladislav G. [Medical Radiology Science Center, Obninsk (Russian Federation); Geras' kin, Stanislav A. [Russian Institute of Agricultural Radiology and Ecology, Obninsk (Russian Federation); Cebulska-Wasilewska, Antonina; Panek, Agnieszka; Wiechec, Anna [Institute of Nuclear Physics, Cracow (Poland)

    2004-06-01

    This research project has been carried out jointly with INP (Poland) to develop technologies to assess the biological efficiency of interaction between radiation and chemicals. Through the cooperative project, KAERI and INP have established wide variety of bioassay techniques applicable to radiation bioscience, human monitoring, molecular epidemiology and environmental science. The joint experiment, in special, made it possible to utilize the merits of both institutes and to upgrade and verify KAERI's current technology level. All results of the cooperative research will be jointly published in high standard scientific journals listed in the Science Citation Index (SCI), which can make the role of fundamental basis for improving relationship between Korea and Poland. Research skills such as Trad-MCN assay, SCGE assay, immunohistochemical assay and molecular assay developed through joint research will be further elaborated and will be continuously used for the collaboration between two institutes.

  13. Strongly Interacting Matter at Finite Chemical Potential: Hybrid Model Approach

    Science.gov (United States)

    Srivastava, P. K.; Singh, C. P.

    2013-06-01

    Search for a proper and realistic equation of state (EOS) for strongly interacting matter used in the study of the QCD phase diagram still appears as a challenging problem. Recently, we constructed a hybrid model description for the quark-gluon plasma (QGP) as well as hadron gas (HG) phases where we used an excluded volume model for HG and a thermodynamically consistent quasiparticle model for the QGP phase. The hybrid model suitably describes the recent lattice results of various thermodynamical as well as transport properties of the QCD matter at zero baryon chemical potential (μB). In this paper, we extend our investigations further in obtaining the properties of QCD matter at finite value of μB and compare our results with the most recent results of lattice QCD calculation.

  14. Mechanism of Interaction between Ionizing Radiation and Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Lee, B. H.; Shin, H. S. (and others)

    2008-03-15

    This research project has been carried out jointly with INP (Poland) to develop technologies for 'Mechanism of Interaction between ionizing radiation and chemicals{sup .} Several biological end-points were assessed in experimental organisms such as higher plants, rats, cell lines and yeast cells to establish proper bioassay techniques. The Tradescantia somatic cell mutation assay was carried out, and immunohistochemistry and hormone assays were done in Fisher 344 rats and cell lines to analyse the combined effect of ionizing radiation with mercury chloride. Using the common regularities of combined actions of two factors, a theoretical model was established, and applied to the thermo radiation action and synergism between two chemicals, as well. The model approach made it possible to predict the condition under which the maximum synergism could be attained. The research results were published in high standard journals and presented in the scientific conferences to verify KAERI's current technology level. The experience of collaboration can be used as a fundamental tool for multinational collaboration, and make the role of improving relationship between Korea and Poland.

  15. Chemical Evolution of Strongly Interacting Quark-Gluon Plasma

    Directory of Open Access Journals (Sweden)

    Ying-Hua Pan

    2014-01-01

    Full Text Available At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c. However, the quark-gluon plasma (QGP system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations.

  16. Identification of new candidate drugs for lung cancer using chemical-chemical interactions, chemical-protein interactions and a K-means clustering algorithm.

    Science.gov (United States)

    Lu, Jing; Chen, Lei; Yin, Jun; Huang, Tao; Bi, Yi; Kong, Xiangyin; Zheng, Mingyue; Cai, Yu-Dong

    2016-01-01

    Lung cancer, characterized by uncontrolled cell growth in the lung tissue, is the leading cause of global cancer deaths. Until now, effective treatment of this disease is limited. Many synthetic compounds have emerged with the advancement of combinatorial chemistry. Identification of effective lung cancer candidate drug compounds among them is a great challenge. Thus, it is necessary to build effective computational methods that can assist us in selecting for potential lung cancer drug compounds. In this study, a computational method was proposed to tackle this problem. The chemical-chemical interactions and chemical-protein interactions were utilized to select candidate drug compounds that have close associations with approved lung cancer drugs and lung cancer-related genes. A permutation test and K-means clustering algorithm were employed to exclude candidate drugs with low possibilities to treat lung cancer. The final analysis suggests that the remaining drug compounds have potential anti-lung cancer activities and most of them have structural dissimilarity with approved drugs for lung cancer.

  17. Understanding Molecular Interactions within Chemically Selective Layered Polymer Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Gary J. Blanchard

    2009-06-30

    This work focuses on two broad issues. These are (1) the molecular origin of the chemical selectivity achieved with ultrathin polymer multilayers, and (2) how the viscoelastic properties of the polymer layers are affected by exposure to solvent and analytes. These issues are inter-related, and to understand them we need to design experiments that probe both the energetic and kinetic aspects of interfacial adsorption processes. This project focuses on controling the chemical structure, thickness, morphology and sequential ordering of polymer layers bound to interfaces using maleimide-vinyl ether and closely related alternating copolymerization chemistry and efficient covalent cross-linking reactions that allow for layer-by-layer polymer deposition. This chemistry has been developed during the funding cycle of this Grant. We have measure the equilibrium constants for interactions between specific layers within the polymer interfaces and size-controlled, surface-functionalized gold nanoparticles. The ability to control both size and functionality of gold nanoparticle model analytes allows us to evaluate the average “pore size” that characterizes our polymer films. We have measured the “bulk” viscosity and shear modulus of the ultrathin polymer films as a function of solvent overlayer identity using quartz crystal microbalance complex impedance measurements. We have measured microscopic viscosity at specific locations within the layered polymer interfaces with time-resolved fluorescence lifetime and depolarization techniques. We combine polymer, cross-linking and nanoparticle synthetic expertise with a host of characterization techniques, including QCM gravimetry and complex impedance analysis, steady state and time-resolved spectroscopies.

  18. Interactions between chemical and electrical kindling of the rat amygdala.

    Science.gov (United States)

    Wasterlain, C G; Morin, A M; Jonec, V

    1982-09-16

    Holtzman rats were implanted with a chemitrode into the left basolateral amygdala, which could then be stimulated electrically (400 microA, 1 s, AC) or chemically by injection of carbachol (1 microliter, 2.7 nmoles, sterile, isotonic). Group A received a daily injection of carbachol and developed kindled seizures. Group B received carbachol mixed with equimolar atropine, which blocked seizures and kindling. After 20 injections, both groups were stimulated electrically once a day and kindled at similar rates. Two additional groups received electrical or sham stimulation, followed by carbachol kindling. No transfer effects were observed. Four additional groups received 27 nmoles of atropine through the chemitrode, followed 15 min later by electrical stimulation, sham stimulation, carbachol injection or saline injection, respectively. Atropine completely blocked carbachol kindling but did not alter the rate of electrical kindling. No different in the number of QNB binding sites was observed in the amygdala of rats sacrificed two weeks after full electrical kindling. The lack of interaction between electrical and carbachol kindling and the failure of atropine to block electrical kindling of the amygdala suggest that the activation of local muscarinic synapses, while essential for carbachol kindling, is not required for electrical kindling of the rat amygdala.

  19. Interactive Chemical Safety for Sustainablity Toxicity Forecaster Dashboard

    Data.gov (United States)

    U.S. Environmental Protection Agency — EPA researchers have been using advances in computational toxicology to address lack of data on the thousands of chemicals. EPA released chemical data on 1,800...

  20. Study on the key problems of interaction between microwave and chemical reaction

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaoqing; HUANG Kama

    2007-01-01

    Microwave has been found as an efficient heating method in chemical industry.However,in present days the interaction between microwave and chemical reactions has not been deeply understood,which restricts a wider application of high power microwave in chemical industry.In this Paper,the key problems of interaction between microwave and chemical reaction are investigated,such as complex effective permittivity of chemical reaction,simulation of microwave heating on chemical reaction and non-thermal effect of microwave,which will enhance further knowledge of the mechanism of interaction between microwave and chemical reaction.Moreover,such an analysis is beneficial for handling with difficulties in application of microwave chemical industry.

  1. Chemical ecology of interactions between human skin microbiota and mosquitoes

    NARCIS (Netherlands)

    Verhulst, N.O.; Takken, W.; Dicke, M.; Schraa, G.; Smallegange, R.C.

    2010-01-01

    Microbiota on the human skin plays a major role in body odour production. The human microbial and chemical signature displays a qualitative and quantitative correlation. Genes may influence the chemical signature by shaping the composition of the microbiota. Recent studies on human skin microbiota,

  2. Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks

    Science.gov (United States)

    Hooper, Michael J.; Ankley, Gerald T.; Cristol, Daniel A.; Maryoung, Lindley A.; Noyes, Pamela D.; Pinkerton, Kent E.

    2013-01-01

    Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical–GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical–climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments.

  3. Prediction of Effective Drug Combinations by Chemical Interaction, Protein Interaction and Target Enrichment of KEGG Pathways

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2013-01-01

    Full Text Available Drug combinatorial therapy could be more effective in treating some complex diseases than single agents due to better efficacy and reduced side effects. Although some drug combinations are being used, their underlying molecular mechanisms are still poorly understood. Therefore, it is of great interest to deduce a novel drug combination by their molecular mechanisms in a robust and rigorous way. This paper attempts to predict effective drug combinations by a combined consideration of: (1 chemical interaction between drugs, (2 protein interactions between drugs’ targets, and (3 target enrichment of KEGG pathways. A benchmark dataset was constructed, consisting of 121 confirmed effective combinations and 605 random combinations. Each drug combination was represented by 465 features derived from the aforementioned three properties. Some feature selection techniques, including Minimum Redundancy Maximum Relevance and Incremental Feature Selection, were adopted to extract the key features. Random forest model was built with its performance evaluated by 5-fold cross-validation. As a result, 55 key features providing the best prediction result were selected. These important features may help to gain insights into the mechanisms of drug combinations, and the proposed prediction model could become a useful tool for screening possible drug combinations.

  4. Non-Chemical Distant Cellular Interactions as a potential confounder of cell biology experiments.

    Science.gov (United States)

    Farhadi, Ashkan

    2014-01-01

    Distant cells can communicate with each other through a variety of methods. Two such methods involve electrical and/or chemical mechanisms. Non-chemical, distant cellular interactions may be another method of communication that cells can use to modify the behavior of other cells that are mechanically separated. Moreover, non-chemical, distant cellular interactions may explain some cases of confounding effects in Cell Biology experiments. In this article, we review non-chemical, distant cellular interactions studies to try to shed light on the mechanisms in this highly unconventional field of cell biology. Despite the existence of several theories that try to explain the mechanism of non-chemical, distant cellular interactions, this phenomenon is still speculative. Among candidate mechanisms, electromagnetic waves appear to have the most experimental support. In this brief article, we try to answer a few key questions that may further clarify this mechanism.

  5. Non-Chemical Distant Cellular Interactions as a potential confounder of Cell Biology Experiments

    Directory of Open Access Journals (Sweden)

    Ashkan eFarhadi

    2014-10-01

    Full Text Available Distant cells can communicate with each other through a variety of methods. Two such methods involve electrical and/or chemical mechanisms. Non-chemical, distant cellular interactions may be another method of communication that cells can use to modify the behavior of other cells that are mechanically separated. Moreover, non-chemical, distant cellular interactions may explain some cases of confounding effects in Cell Biology experiments. In this article, we review non-chemical, distant cellular interactions studies to try to shed light on the mechanisms in this highly unconventional field of cell biology. Despite the existence of several theories that try to explain the mechanism of non-chemical, distant cellular interactions, this phenomenon is still speculative. Among candidate mechanisms, electromagnetic waves appear to have the most experimental support. In this brief article, we try to answer a few key questions that may further clarify this mechanism.

  6. A four-component organogel based on orthogonal chemical interactions.

    Science.gov (United States)

    Luisier, Nicolas; Schenk, Kurt; Severin, Kay

    2014-09-14

    A thermoresponsive organogel was obtained by orthogonal assembly of four compounds using dynamic covalent boronate ester and imine bonds, as well as dative boron-nitrogen bonds. It is shown that the gel state can be disrupted or reinforced by chemicals which undergo exchange reactions with the gel components.

  7. Physico-chemical aspects of modified UMo/AL interaction

    Energy Technology Data Exchange (ETDEWEB)

    Cornen, M.; Mazaudier, F.; Iltis, X.; Rodier, M.; Dubois, S. [CEA Cadarache, 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Combustibles; Lemoine, P. [CEA Saclay (DEN/DSOE), 91 - Gif sur Yvette (France)

    2007-07-01

    This paper describes the first results of out-of-pile interdiffusion tests focused on the effects of Si added in the Al matrix on the interaction with UMo particles.Interdiffusion couples have been realized from 3 different UMo alloys, 6 Al-Si alloys, with Si content ranging from 0.11 to 12 % wt, and 3 Al-alloys with other additions (Fe, Ni, Mg, Mg+Si). Silicon addition seems to have an important effect on the growth rate of the interaction layer (IL): as a matter of fact, when Si content increases, IL thickness decreases. In the case of multilayered IL, the interaction formed near the UMo side is richer in Si than the one neighbouring the Al matrix. Last point of interest is that the Al composition and microstructure have also a significant effect on the interaction. As shown by the first experiments, Si has to be sufficiently available in the matrix to interact. If precipitated too far from interface or with other elements such as Al-Fe-Si compounds it does not play its role anymore and we can assist to UMo decomposition.

  8. Accelerating Wave Function Convergence in Interactive Quantum Chemical Reactivity Studies

    CERN Document Server

    Mühlbach, Adrian H; Reiher, Markus

    2015-01-01

    The inherently high computational cost of iterative self-consistent-field (SCF) methods proves to be a critical issue delaying visual and haptic feedback in real-time quantum chemistry. In this work, we introduce two schemes for SCF acceleration. They provide a guess for the initial density matrix of the SCF procedure generated by extrapolation techniques. SCF optimizations then converge in fewer iterations, which decreases the execution time of the SCF optimization procedure. To benchmark the proposed propagation schemes, we developed a test bed for performing quantum chemical calculations on sequences of molecular structures mimicking real-time quantum chemical explorations. Explorations of a set of six model reactions employing the semi-empirical methods PM6 and DFTB3 in this testing environment showed that the proposed propagation schemes achieved speedups of up to thirty percent as a consequence of a reduced number of SCF iterations.

  9. Botanical insecticides inspired by plant-herbivore chemical interactions.

    Science.gov (United States)

    Miresmailli, Saber; Isman, Murray B

    2014-01-01

    Plants have evolved a plethora of secondary chemicals to protect themselves against herbivores and pathogens, some of which have been used historically for pest management. The extraction methods used by industry render many phytochemicals ineffective as insecticides despite their bioactivity in the natural context. In this review, we examine how plants use their secondary chemicals in nature and compare this with how they are used as insecticides to understand why the efficacy of botanical insecticides can be so variable. If the commercial production of botanical insecticides is to become a viable pest management option, factors such as production cost, resource availability, and extraction and formulation techniques need be considered alongside innovative application technologies to ensure consistent efficacy of botanical insecticides.

  10. Physical and chemical interactions in cold gelation of food proteins

    NARCIS (Netherlands)

    Alting, A.C.; Jongh, de H.H.J.; Visschers, R.W.; Simons, J.W.F.A.

    2002-01-01

    pH-Induced cold gelation of whey proteins is a two-step process. After protein aggregates have been prepared by heat treatment, gelation is established at ambient temperature by gradually lowering the pH. To demonstrate the importance of electrostatic interactions between aggregates during this

  11. Physical and chemical interactions in cold gelation of food proteins

    NARCIS (Netherlands)

    Alting, A.C.; Jongh, de H.H.J.; Visschers, R.W.; Simons, J.W.F.A.

    2002-01-01

    pH-Induced cold gelation of whey proteins is a two-step process. After protein aggregates have been prepared by heat treatment, gelation is established at ambient temperature by gradually lowering the pH. To demonstrate the importance of electrostatic interactions between aggregates during this latt

  12. Physical and chemical interactions in cold gelation of food proteins

    NARCIS (Netherlands)

    Alting, A.C.; Jongh, de H.H.J.; Visschers, R.W.; Simons, J.W.F.A.

    2002-01-01

    pH-Induced cold gelation of whey proteins is a two-step process. After protein aggregates have been prepared by heat treatment, gelation is established at ambient temperature by gradually lowering the pH. To demonstrate the importance of electrostatic interactions between aggregates during this latt

  13. Chemical Potential Dependence of the Dressed-Quark Propagator from an Effective Quark-Quark Interaction

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; PING Jia-Lun; SUN Wei-Min; CHANG Chao-Hsi; WANG Fan

    2002-01-01

    We exhibit a method for obtaining the low chemical potential dependence of the dressed quark propagatorfrom an effective quark-quark interaction model. Within this approach we explore the chemical potential dependenceof the dressed-quark propagator, which provides a means of determining the behavior of the chiral and deconfinementorder parameters. A comparison with the results of previous researches is given.

  14. Irradiation and lithium presence influence on the crystallographic nature of zirconia in the framework of PWR zircaloy 4 fuel cladding corrosion study; Influence de l'irradiation et de la presence du lithium sur la nature cristallographique de la zircone dans le cadre de l'etude de la corrosion du zircaloy 4 en milieu reacteur a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Gibert, C

    1999-07-01

    The-increasing deterioration of the initially protective zirconia layer is one of the hypotheses which can explain the impairment with time of PWR fuel cladding corrosion. This deterioration could be worsened by irradiation or lithium presence in the oxidizing medium. The aim of this thesis was to underline the influence of those two parameters on zirconia crystallographic nature. We first studied the impact of ionic irradiation on pure, powdery, monoclinic zirconia and oxidation formed zirconia, mainly with X-ray diffraction and Raman microscopy. The high or low energy particles used (Kr{sup n+-}, Ar{sup n+}) respectively favored electronic or atomic defaults production. The crystallographic analyses showed that these irradiation have a significant effect on zirconia by inducing nucleation or growth of tetragonal phase. The extent depends on sample nature and particles energy. In all cases, phase transformation is correlated with crystalline parameters, grain size and especially micro-stress changes. The results are consistent with those obtained with 1 to 5 cycles PWR claddings. Therefore, the corrosion acceleration observed in reactor can partly be explained by the stress fields appearance under irradiation, which is particularly detrimental to zirconia layer cohesion. Last, we have underlined that the presence of considerable amounts of lithium in the oxidizing medium ((> 700 ppm) induces the disappearance of the tetragonal zirconia located at the metal/oxide interface and the appearance of a porosity of the dense under layer, which looses its protectiveness. (author)

  15. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups

    Science.gov (United States)

    Lee, Gyudo; Lee, Hyungbeen; Nam, Kihwan; Han, Jae-Hee; Yang, Jaemoon; Lee, Sang Woo; Yoon, Dae Sung; Eom, Kilho; Kwon, Taeyun

    2012-10-01

    We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups.

  16. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups.

    Science.gov (United States)

    Lee, Gyudo; Lee, Hyungbeen; Nam, Kihwan; Han, Jae-Hee; Yang, Jaemoon; Lee, Sang Woo; Yoon, Dae Sung; Eom, Kilho; Kwon, Taeyun

    2012-10-31

    We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups.

  17. Nanoscale chemical interaction enhances the physical properties of bioglass composites.

    Science.gov (United States)

    Ravarian, Roya; Zhong, Xia; Barbeck, Mike; Ghanaati, Shahram; Kirkpatrick, Charles James; Murphy, Ciara M; Schindeler, Aaron; Chrzanowski, Wojciech; Dehghani, Fariba

    2013-10-22

    Bioglasses are favorable biomaterials for bone tissue engineering; however, their applications are limited due to their brittleness. In addition, the early failure in the interface is a common problem of composites of bioglass and a polymer with high mechanical strength. This effect is due to the phase separation, nonhomogeneous mixture, nonuniform mechanical strength, and different degradation properties of two compounds. To address these issues, in this study a nanoscale interaction between poly(methyl methacrylate) (PMMA) and bioactive glass was formed via silane coupling agent (3-trimethoxysilyl)propyl methacrylate (MPMA). A monolith was produced at optimum composition from this hybrid by the sol-gel method at 50 °C with a rapid gelation time (hybrid. The in vivo studies in mice demonstrated that the integrity of the hybrids was maintained in subcutaneous implantation. They induced mainly a mononuclear phagocytic tissue reaction with a low level of inflammation, while bioglass provoked a tissue reaction with TRAP-positive multinucleated giant cells. These results demonstrated that the presence of a nanoscale interaction between bioglass and PMMA affects the properties of bioglass and broadens its potential applications for bone replacement.

  18. Chemical interaction silicon nitride ceramics and iron alloys

    Directory of Open Access Journals (Sweden)

    Oliveira, F. J.

    2000-12-01

    Full Text Available Metal/ceramic diffusion experiments are helpful to study bonding mechanisms or the effect of metal composition on the chemical wear of ceramic cutting tools. The reaction kinetics of Fe alloys/Si3 N4 ceramic diffusion couples was investigated in the temperature range 1050ºC-1250ºC, for 0.5h to 80h, under inert atmosphere. Optical microscopy, SEM and EPMA were carried out in cross sections of the reacted pairs. Si3N4 decomposes into Si and N that dissolve and diffuse through the metal. Both the diffusion zone on the metal side and the reaction zone on the ceramic side obey parabolic growth laws of time, with activation energies in the range Q=310-460kJmol-1. The amount of dissolved Si, the length of the diffusion zone and thus the reactivity of the ceramic increase as the alloy carbon content decreases. Due to Si accumulation, the α-Fe solid solution is stabilised at the reaction temperature and a steep decrease in the Si concentration is observed beyond the diffusion zone. The reinforcement of the Si3N4 composites with A12O3 platelets enhances the chemical resistance of the ceramic due to the inertness of this oxide and to the partial crystallisation of the intergranular phase. Other dispersoids such as HfN, BN and TiN do not improve the chemical resistance of the matrix by iron attack.

    Los experimentos de difusión metal/cerámica permiten estudiar mecanismos de unión y analizar el efecto de la composición del metal en el desgaste químico de herramientas de corte cerámicas. En este trabajo se investigó la cinética de reacción en pares de difusión aleaciones de Fe/Si3N4 a temperaturas entre 1050ºC-1250ºC, tiempos entre 0.5h a 80h, en atmósfera inerte. Las secciones transversales de los pares de difusión se analizaron mediante microscopía óptica, SEM y microsonda electrónica. El Si3N4 se descompone en Si y N que se disuelven y difunden en el metal. Tanto la zona de difusión en el metal como la zona de reacción en la cer

  19. Tailoring the Interfacial Chemical Interaction for High-Efficiency Perovskite Solar Cells.

    Science.gov (United States)

    Zuo, Lijian; Chen, Qi; De Marco, Nicholas; Hsieh, Yao-Tsung; Chen, Huajun; Sun, Pengyu; Chang, Sheng-Yung; Zhao, Hongxiang; Dong, Shiqi; Yang, Yang

    2017-01-11

    The ionic nature of perovskite photovoltaic materials makes it easy to form various chemical interactions with different functional groups. Here, we demonstrate that interfacial chemical interactions are a critical factor in determining the optoelectronic properties of perovskite solar cells. By depositing different self-assembled monolayers (SAMs), we introduce different functional groups onto the SnO2 surface to form various chemical interactions with the perovskite layer. It is observed that the perovskite solar cell device performance shows an opposite trend to that of the energy level alignment theory, which shows that chemical interactions are the predominant factor governing the interfacial optoelectronic properties. Further analysis verifies that proper interfacial interactions can significantly reduce trap state density and facilitate the interfacial charge transfer. Through use of the 4-pyridinecarboxylic acid SAM, the resulting perovskite solar cell exhibits striking improvements to the reach the highest efficiency of 18.8%, which constitutes an ∼10% enhancement compared to those without SAMs. Our work highlights the importance of chemical interactions at perovskite/electrode interfaces and paves the way for further optimizing performances of perovskite solar cells.

  20. Chemical and mechanical interactions of interstitials with vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    DiStefano, J.R.; Chitwood, L.D.; DeVan, J.H. [Oak Ridge National Laboratory, TN (United States)

    1996-04-01

    Oxidation studies of V-4Cr-4Ti were conducted in air and reduced oxygen partial pressures (10{sup 4}, 10{sup -5} and 10{sup -6} torr). Reaction rates were determined by weight change measurements and chemical analyses. Mechanical properties after the exposures were determined by room temperature tensile tests. In air at 400 and 500{degrees}C, oxide films form on the surface. Initially, rates are high but decrease with time reaching similiar values to those found in oxygen partial pressures at 10{sup -4}, 10{sup -5}, and 10{sup -6} torr. At 400{degrees}C, oxygen pick-up followed a logarithmic function of time and was confined to regions near the surface. Little change in room temperature tensile properties was noted for oxygen increase up to 1500 ppm. Thermal cycling specimens from 400{degrees}C to room temperature up to 14 times had no apparent effect on oxidation rate or tensile properties. At 500{degrees}C, oxygen pick-up appeared to follow a parabolic relation with time. Rates were {approx} 10 times those at 400{degrees}C and correspondingly larger oxygen increases occurred when compared with the 400{degrees}C tests after similiar time periods. This resulted in a significant decrease in total elongation after 240 h. At reduced oxygen partial pressures, rates were measured for times <100 h. Data are relatively sparse but generally show a slightly higher initial rate before slowing. At 400{degrees}C increases to {approx}200 ppm oxygen were found with no effect on room temperature elongation. At 500{degrees}C increase in oxygen of 2400 ppm after 50h/10{sup -5} torr resulted in a decrease of around 25% in room temperature elongation. By comparison, exposure to air at 500{degrees}C for 12 h caused nearly the same results.

  1. Physical and chemical interactions in cold gelation of food proteins.

    Science.gov (United States)

    Alting, Arno C; de Jongh, Harmen H J; Visschers, Ronald W; Simons, Jan-Willem F A

    2002-07-31

    pH-Induced cold gelation of whey proteins is a two-step process. After protein aggregates have been prepared by heat treatment, gelation is established at ambient temperature by gradually lowering the pH. To demonstrate the importance of electrostatic interactions between aggregates during this latter process, beta-lactoglobulin aggregates with a decreased iso-electric point were prepared via succinylation of primary amino groups. The kinetics of pH-induced gelation was affected significantly, with the pH gelation curves shifting to lower pH after succinylation. With increasing modification, the pH of gelation decreased to about 2.5. In contrast, unmodified aggregates gel around pH 5. Increasing the iso-electric point of beta-lactoglobulin via methylation of carboxylic acid groups resulted in gelation at more alkaline pH values. Comparable results were obtained with whey protein isolate. At low pH disulfide cross-links between modified aggregates were not formed after gelation and the gels displayed both syneresis and spontaneous gel fracture, in this way resembling the morphology of previously characterized thiol-blocked whey protein isolate gels (Alting, et al., J. Agric. Food Chem. 2000, 48, 5001-5007). Our results clearly demonstrate the importance of the net electric charge of the aggregates during pH-induced gelation. In addition, the absence of disulfide bond formation between aggregates during low-pH gelation was demonstrated with the modified aggregates.

  2. Investigation of the chemical interaction in the TiC-Si3N4 system

    Directory of Open Access Journals (Sweden)

    Izhevskyi V.A.

    1999-01-01

    Full Text Available Chemical interaction in the TiCSi3N4 system was investigated. Thermodynamic calculations and kinetic analysis were carried out for a number of powder mixtures with various TiC:Si3N4 molar ratios in the temperature range 1300-1750 °C. Stability regions of the TiC-Si3N4 composites were defined. It was shown that the main reaction products are silicon carbide and titanium carbonitride. The overall chemical interaction is described in terms of chemical reaction between titanium carbide and silicon nitride, and the diffusion of carbon and nitrogen through the coherent reaction products layer after completion of the initial direct interaction of the components.

  3. Improving analytical methods for protein-protein interaction through implementation of chemically inducible dimerization

    DEFF Research Database (Denmark)

    Andersen, T. G.; Nintemann, S. J.; Marek, M.;

    2016-01-01

    When investigating interactions between two proteins with complementary reporter tags in yeast two-hybrid or split GFP assays, it remains troublesome to discriminate true-from false-negative results and challenging to compare the level of interaction across experiments. This leads to decreased...... sensitivity and renders analysis of weak or transient interactions difficult to perform. In this work, we describe the development of reporters that can be chemically induced to dimerize independently of the investigated interactions and thus alleviate these issues. We incorporated our reporters...

  4. Genome-wide Mapping of Cellular Protein-RNA Interactions Enabled by Chemical Crosslinking

    Institute of Scientific and Technical Information of China (English)

    Xiaoyu Li; Jinghui Song; Chengqi Yi

    2014-01-01

    RNA-protein interactions influence many biological processes. Identifying the binding sites of RNA-binding proteins (RBPs) remains one of the most fundamental and important chal-lenges to the studies of such interactions. Capturing RNA and RBPs via chemical crosslinking allows stringent purification procedures that significantly remove the non-specific RNA and protein interactions. Two major types of chemical crosslinking strategies have been developed to date, i.e., UV-enabled crosslinking and enzymatic mechanism-based covalent capture. In this review, we com-pare such strategies and their current applications, with an emphasis on the technologies themselves rather than the biology that has been revealed. We hope such methods could benefit broader audi-ence and also urge for the development of new methods to study RNA RBP interactions.

  5. A novel interactive preferential evolutionary method for controller tuning in chemical processes☆

    Institute of Scientific and Technical Information of China (English)

    Chong Su; Hongguang Li

    2015-01-01

    In response to many multi-attribute decision-making (MADM) problems involved in chemical processes such as controller tuning, which suffer human's subjective preferential nature in human–computer interactions, a novel affective computing and preferential evolutionary solution is proposed to adapt human–computer interaction mechanism. Based on the stimulating response mechanism, an improved affective computing model is intro-duced to quantify decision maker's preference in selections of interactive evolutionary computing. In addition, the mathematical relationship between affective space and decision maker's preferences is constructed. Subse-quently, a human–computer interactive preferential evolutionary algorithm for MADM problems is proposed, which deals with attribute weights and optimal solutions based on preferential evolution metrics. To exemplify applications of the proposed methods, some test functions and, emphatical y, control er tuning issues associated with a chemical process are investigated, giving satisfactory results.

  6. Improving analytical methods for protein-protein interaction through implementation of chemically inducible dimerization

    DEFF Research Database (Denmark)

    Andersen, Tonni Grube; Nintemann, Sebastian; Marek, Magdalena

    2016-01-01

    into the widely used split ubiquitin-, bimolecular fluorescence complementation (BiFC)- and Forster resonance energy transfer (FRET)-based methods and investigated different protein-protein interactions in yeast and plants. We demonstrate the functionality of this concept by the analysis of weakly interacting......When investigating interactions between two proteins with complementary reporter tags in yeast two-hybrid or split GFP assays, it remains troublesome to discriminate true-from false-negative results and challenging to compare the level of interaction across experiments. This leads to decreased...... sensitivity and renders analysis of weak or transient interactions difficult to perform. In this work, we describe the development of reporters that can be chemically induced to dimerize independently of the investigated interactions and thus alleviate these issues. We incorporated our reporters...

  7. Prediction of Drug Indications Based on Chemical Interactions and Chemical Similarities

    Directory of Open Access Journals (Sweden)

    Guohua Huang

    2015-01-01

    Full Text Available Discovering potential indications of novel or approved drugs is a key step in drug development. Previous computational approaches could be categorized into disease-centric and drug-centric based on the starting point of the issues or small-scaled application and large-scale application according to the diversity of the datasets. Here, a classifier has been constructed to predict the indications of a drug based on the assumption that interactive/associated drugs or drugs with similar structures are more likely to target the same diseases using a large drug indication dataset. To examine the classifier, it was conducted on a dataset with 1,573 drugs retrieved from Comprehensive Medicinal Chemistry database for five times, evaluated by 5-fold cross-validation, yielding five 1st order prediction accuracies that were all approximately 51.48%. Meanwhile, the model yielded an accuracy rate of 50.00% for the 1st order prediction by independent test on a dataset with 32 other drugs in which drug repositioning has been confirmed. Interestingly, some clinically repurposed drug indications that were not included in the datasets are successfully identified by our method. These results suggest that our method may become a useful tool to associate novel molecules with new indications or alternative indications with existing drugs.

  8. Experimental studies of thermal and chemical interactions between molten aluminum and water

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, A.A.; Corradini, M.L. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    The possibility of rapid physical and chemical aluminum/water interactions during a core melt accident in a noncommercial reactor (e.g., HFIR, ATR) has resulted in extensive research to determine the mechanism by which these interactions occur and propagate on an explosive time scale. These events have been reported in nuclear testing facilities, i.e., during SPERT 1D experiment, and also in aluminum casting industries. Although rapid chemical reactions between molten aluminum and water have been subject of many studies, very few reliable measurements of the extent of the chemical reactions have thus far been made. We have modified an existing 1-D shock tube facility to perform experiments in order to determine the extent of the explosive thermal/chemical interactions between molton aluminum and water by measuring important physical quantities such as the maximum dynamic pressure and the amount of the generated hydrogen. Experimental results show that transient pressures greater than 69 MPa with a rise time of less than 125 {mu}sec can occur as the result of the chemical reaction of 4.2 grams of molton aluminum (approximately 15% of the total mass of the fuel of 28 grams) at 980 C with room temperature water.

  9. On the Use of Interactive Texts in Undergraduate Chemical Reaction Engineering Courses: A Pedagogical Experience

    Science.gov (United States)

    Asensio, Daniela A.; Barassi, Francisca J.; Zambon, Mariana T.; Mazza, Germán D.

    2010-01-01

    This paper describes the results of a pedagogical experience carried out at the University of Comahue, Argentina, with an interactive text (IT) concerning Homogeneous Chemical Reactors Analysis. The IT was built on the frame of the "Mathematica" software with the aim of providing students with a robust computational tool. Students'…

  10. Phthalic Acid Chemical Probes Synthesized for Protein-Protein Interaction Analysis

    Directory of Open Access Journals (Sweden)

    Chin-Jen Wu

    2013-06-01

    Full Text Available Plasticizers are additives that are used to increase the flexibility of plastic during manufacturing. However, in injection molding processes, plasticizers cannot be generated with monomers because they can peel off from the plastics into the surrounding environment, water, or food, or become attached to skin. Among the various plasticizers that are used, 1,2-benzenedicarboxylic acid (phthalic acid is a typical precursor to generate phthalates. In addition, phthalic acid is a metabolite of diethylhexyl phthalate (DEHP. According to Gene_Ontology gene/protein database, phthalates can cause genital diseases, cardiotoxicity, hepatotoxicity, nephrotoxicity, etc. In this study, a silanized linker (3-aminopropyl triethoxyslane, APTES was deposited on silicon dioxides (SiO2 particles and phthalate chemical probes were manufactured from phthalic acid and APTES–SiO2. These probes could be used for detecting proteins that targeted phthalic acid and for protein-protein interactions. The phthalic acid chemical probes we produced were incubated with epithelioid cell lysates of normal rat kidney (NRK-52E cells to detect the interactions between phthalic acid and NRK-52E extracted proteins. These chemical probes interacted with a number of chaperones such as protein disulfide-isomerase A6, heat shock proteins, and Serpin H1. Ingenuity Pathways Analysis (IPA software showed that these chemical probes were a practical technique for protein-protein interaction analysis.

  11. Analysis of thermal-chemical interactions at the ceramic mould – molten nickel alloy interface

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2010-10-01

    Full Text Available A model of thermal-chemical interactions at the ceramic mould – molten nickel alloy interface was described. Studies were carried out on mould coated with a layer of modifier based on zirconium silicate and cobalt aluminate. The thermodynamic calculations indicated thepossibility of chemical reactions taking place between the chemically active nickel alloy constituents (Al, Ti, Hf, Ta and Nb andcomponents of the modifying coating. The result of such interactions is possible formation on the surface of mould and casting of “newcompounds” which can be the source of casting defects, like burns-on, pitting, etc., the fact proved by extensive X-ray microanalysis. Inaddition, the possibility of crack formation on mould surface and of the molten metal penetration into thus formed crevices was observed.

  12. Chemical Interactions and Their Role in the Microphase Separation of Block Copolymer Thin Films

    Directory of Open Access Journals (Sweden)

    Richard A. Farrell

    2009-08-01

    Full Text Available The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP systems. BCP systems self-assemble via a thermodynamic driven process where chemical dis-affinity between the blocks driving them part is balanced by a restorative force deriving from the chemical bond between the blocks. These systems are attracting much interest because of their possible role in nanoelectronic fabrication. This form of self-assembly can obtain highly regular nanopatterns in certain circumstances where the orientation and alignment of chemically distinct blocks can be guided through molecular interactions between the polymer and the surrounding interfaces. However, for this to be possible, great care must be taken to properly engineer the interactions between the surfaces and the polymer blocks. The optimum methods of structure directing are chemical pre-patterning (defining regions on the substrate of different chemistry and graphoepitaxy (topographical alignment but both centre on generating alignment through favourable chemical interactions. As in all self-assembling systems, the problems of defect formation must be considered and the origin of defects in these systems is explored. It is argued that in these nanostructures equilibrium defects are relatively few and largely originate from kinetic effects arising during film growth. Many defects also arise from the confinement of the systems when they are ‘directed’ by topography. The potential applications of these materials in electronics are discussed.

  13. Chemical interactions and their role in the microphase separation of block copolymer thin films.

    Science.gov (United States)

    Farrell, Richard A; Fitzgerald, Thomas G; Borah, Dipu; Holmes, Justin D; Morris, Michael A

    2009-08-25

    The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP) systems. BCP systems self-assemble via a thermodynamic driven process where chemical dis-affinity between the blocks driving them part is balanced by a restorative force deriving from the chemical bond between the blocks. These systems are attracting much interest because of their possible role in nanoelectronic fabrication. This form of self-assembly can obtain highly regular nanopatterns in certain circumstances where the orientation and alignment of chemically distinct blocks can be guided through molecular interactions between the polymer and the surrounding interfaces. However, for this to be possible, great care must be taken to properly engineer the interactions between the surfaces and the polymer blocks. The optimum methods of structure directing are chemical pre-patterning (defining regions on the substrate of different chemistry) and graphoepitaxy (topographical alignment) but both centre on generating alignment through favourable chemical interactions. As in all self-assembling systems, the problems of defect formation must be considered and the origin of defects in these systems is explored. It is argued that in these nanostructures equilibrium defects are relatively few and largely originate from kinetic effects arising during film growth. Many defects also arise from the confinement of the systems when they are 'directed' by topography. The potential applications of these materials in electronics are discussed.

  14. Impact of fluid-rock chemical interactions on tracer transport in fractured rocks.

    Science.gov (United States)

    Mukhopadhyay, Sumit; Liu, H-H; Spycher, N; Kennedy, B M

    2013-11-01

    In this paper, we investigate the impact of chemical interactions, in the form of mineral precipitation and dissolution reactions, on tracer transport in fractured rocks. When a tracer is introduced in fractured rocks, it moves through the fracture primarily by advection and it also enters the stagnant water of the surrounding rock matrix through diffusion. Inside the porous rock matrix, the tracer chemically interacts with the solid materials of the rock, where it can precipitate depending on the local equilibrium conditions. Alternatively, it can be dissolved from the solid phase of the rock matrix into the matrix pore water, diffuse into the flowing fluids of the fracture and is advected out of it. We show that such chemical interactions between the fluid and solid phases have significant impact on tracer transport in fractured rocks. We invoke the dual-porosity conceptualization to represent the fractured rocks and develop a semi-analytical solution to describe the transient transport of tracers in interacting fluid-rock systems. To test the accuracy and stability of the semi-analytical solution, we compare it with simulation results obtained with the TOUGHREACT simulator. We observe that, in a chemically interacting system, the tracer breakthrough curve exhibits a pseudo-steady state, where the tracer concentration remains more or less constant over a finite period of time. Such a pseudo-steady condition is not observed in a non-reactive fluid-rock system. We show that the duration of the pseudo-state depends on the physical and chemical parameters of the system, and can be exploited to extract information about the fractured rock system, such as the fracture spacing and fracture-matrix interface area.

  15. Diversity-oriented synthetic strategy for developing a chemical modulator of protein-protein interaction

    Science.gov (United States)

    Kim, Jonghoon; Jung, Jinjoo; Koo, Jaeyoung; Cho, Wansang; Lee, Won Seok; Kim, Chanwoo; Park, Wonwoo; Park, Seung Bum

    2016-10-01

    Diversity-oriented synthesis (DOS) can provide a collection of diverse and complex drug-like small molecules, which is critical in the development of new chemical probes for biological research of undruggable targets. However, the design and synthesis of small-molecule libraries with improved biological relevance as well as maximized molecular diversity represent a key challenge. Herein, we employ functional group-pairing strategy for the DOS of a chemical library containing privileged substructures, pyrimidodiazepine or pyrimidine moieties, as chemical navigators towards unexplored bioactive chemical space. To validate the utility of this DOS library, we identify a new small-molecule inhibitor of leucyl-tRNA synthetase-RagD protein-protein interaction, which regulates the amino acid-dependent activation of mechanistic target of rapamycin complex 1 signalling pathway. This work highlights that privileged substructure-based DOS strategy can be a powerful research tool for the construction of drug-like compounds to address challenging biological targets.

  16. An insight into chemical kinetics and turbulence-chemistry interaction modeling in flameless combustion

    Directory of Open Access Journals (Sweden)

    Amir Azimi, Javad Aminian

    2015-01-01

    Full Text Available Computational Fluid Dynamics (CFD study of flameless combustion condition is carried out by solving the Reynolds-Averaged Navier-Stokes (RANS equations in the open-source CFD package of OpenFOAM 2.1.0. Particular attention is devoted to the comparison of three global and detailed chemical mechanisms using the Partially Stirred Reactor (PaSR combustion model for the turbulence-chemistry interaction treatment. The OpenFOAM simulations are assessed against previously published CFD results using the Eddy Dissipation Concept (EDC combustion model as well as the experimental data available in the literature. Results show that global chemical mechanisms provide acceptable predictions of temperature and major species fields in flameless mode with much lower computational costs comparing with the detailed chemical mechanisms. However, incorporation of detailed chemical mechanisms with proper combustion models is crucial to account for finite-rate chemistry effects and accurately predict net production of minor species.

  17. Molecular characterization of cancer reveals interactions between ionizing radiation and chemicals on rat mammary carcinogenesis.

    Science.gov (United States)

    Imaoka, Tatsuhiko; Nishimura, Mayumi; Doi, Kazutaka; Tani, Shusuke; Ishikawa, Ken-ichi; Yamashita, Satoshi; Ushijima, Toshikazu; Imai, Takashi; Shimada, Yoshiya

    2014-04-01

    Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were γ-irradiated (0.2-2 Gy) and/or exposed to 1-methyl-1-nitrosourea (MNU) (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model.

  18. DEVELOPMENT OF INTERACTIVE E-BOOK BASED ON CHEMICAL REPRESENTATION REFER TO CURRICULUM 2013

    Directory of Open Access Journals (Sweden)

    L. Tania

    2015-11-01

    Full Text Available This research aimed to develop an interactive e-book based representations of chemistry; describes the characteristics of the interactive e-book developed; the teachers responses in content suitability with curriculum and graphics aspects; and student responses in readibility aspects. The method used was research and development. The characteristics of interactive e-book: it was developed referring to the core competencies (KI and basic competence (KD in the curriculum 2013, allowed active interaction between students and e-book, completed with pictures, animations or videos in three levels of the chemical representation. Teachers’ responses to the content suitability and graphic aspects were very good with the percentage of each 98.46% and 97.5%. The students’ responses in readibility aspects was very good with percentage of 88.5%.

  19. DEVELOPMENT OF INTERACTIVE E-BOOK BASED ON CHEMICAL REPRESENTATION REFER TO CURRICULUM 2013

    Directory of Open Access Journals (Sweden)

    L. Tania

    2015-11-01

    Full Text Available This research aimed to develop an interactive e-book based representations of chemistry; describes the characteristics of the interactive e-book developed; the teachers responses in content suitability with curriculum and graphics aspects; and student responses in readibility aspects. The method used was research and development. The characteristics of interactive e-book: it was developed referring to the core competencies (KI and basic competence (KD in the curriculum 2013, allowed active interaction between students and e-book, completed with pictures, animations or videos in three levels of the chemical representation. Teachers’ responses to the content suitability and graphic aspects were very good with the percentage of each 98.46% and 97.5%. The students’ responses in readibility aspects was very good with percentage of 88.5%.

  20. Improving analytical methods for protein-protein interaction through implementation of chemically inducible dimerization

    DEFF Research Database (Denmark)

    Andersen, Tonni Grube; Nintemann, Sebastian; Marek, Magdalena;

    2016-01-01

    into the widely used split ubiquitin-, bimolecular fluorescence complementation (BiFC)- and Forster resonance energy transfer (FRET)-based methods and investigated different protein-protein interactions in yeast and plants. We demonstrate the functionality of this concept by the analysis of weakly interacting...... proteins from specialized metabolism in the model plant Arabidopsis thaliana. Our results illustrate that chemically induced dimerization can function as a built-in control for split-based systems that is easily implemented and allows for direct evaluation of functionality....

  1. Fabrication and Measurements of Hoop Strength of a Multi-Layered SiC Composite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejong; Lee, Jongmin; Kim, Weon Ju; Park, Ji Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In this study, the influence of the winding patterns of the SiC fiber on the fiber volume fraction and hoop strength were investigated. Silicon carbide has a low neutron absorption cross section, a high melting point, and low chemical interaction, making it possible to use as fuel cladding in light water reactors. A multi-layered SiC composite tube as the LWR fuel cladding is composed of the monolith SiC inner layer, SiC/SiC composite intermediate layer, and monolith SiC outer layer.

  2. The role of chemical interactions between thorium, cerium, and lanthanum in lymphocyte toxicity.

    Science.gov (United States)

    Oliveira, Monica S; Duarte, Isabelle M; Paiva, Amanda V; Yunes, Samira N; Almeida, Carlos E; Mattos, Rita C; Sarcinelli, Paula N

    2014-01-01

    Thorium, cerium, and lanthanum are metals present in several types of minerals, the most common of which is monazite. Cerium and lanthanum are elements in the lanthanides series. Thorium, an actinide metal, is a hazardous element due to its radioactive characteristics. There is a lack of information describing the possible chemical interactions among these elements and the effects they may have on humans. Toxicological analyses were performed using cell viability, cell death, and DNA damage assays. Chemical interactions were evaluated based on the Loewe additivity model. The results indicate that thorium and cerium individually have no toxic effects on lymphocytes. However, thorium associated with lanthanum increases the toxicity of this element, thereby reducing the viability of lymphocytes at low concentrations of metals in the mixture.

  3. Is there a chemical interaction between calcium phosphates and organic compounds in the organic/inorganic composites?

    Energy Technology Data Exchange (ETDEWEB)

    Dorozhkin, S.V. [Research Inst. of Fertilisers, Moscow (Russian Federation)

    2001-07-01

    Solid composites of three biologically relevant calcium phosphates and hydroxypropylmethylcellulose (HPMC) were prepared at temperatures of 121 C. Properties of the composites obtained were studied by FTIR, X-ray diffraction, and SEM techniques. Special attention was devoted to seeking of a possible chemical interaction between the calcium phosphates and HPMC. No chemical interaction was found. Thus, HPMC was proven to have no influence on the chemical properties of calcium phosphates. (orig.)

  4. Multiple stressor effects in Chlamydomonas reinhardtii – Toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Korkaric, Muris [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland); Behra, Renata; Fischer, Beat B. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); Junghans, Marion [Swiss Center for Applied Ecotoxicology Eawag-EPFL, 8600, Duebendorf (Switzerland); Eggen, Rik I.L., E-mail: rik.eggen@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland)

    2015-05-15

    Highlights: • Systematic study of multiple stressor effects of UVR and chemicals in C. reinhardtii. • UVR and chemicals did not act independently on algal photosynthesis and reproduction. • Multiple stressor effects of UVR and chemicals depended on chemical MOA. • Synergistic effect interactions not limited to oxidative stress inducing chemicals. • Multiple MOAs of UVR may limit applicability of current prediction models. - Abstract: The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are

  5. Influence of the Chemical Interactions on the Removal Rate of Different Salts in Electrokinetic Desalination Processes

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    2011-01-01

    Electrokinetic desalination techniques have been successfully applied for the prevention of salt-induced deterioration problems of masonry and other construction materials. A mathematical model for electrochemical desalination treatments is described, based on the Poisson-Nernst-Planck system...... and sculptures. Simulations of the desalination treatment of brick samples contaminated with these target contaminants are shown. The influence of the chemical interactions on the efficiency is highlighted in the results....

  6. Quantitative Chemical-Genetic Interaction Map Connects Gene Alterations to Drug Responses | Office of Cancer Genomics

    Science.gov (United States)

    In a recent Cancer Discovery report, CTD2 researchers at the University of California in San Francisco developed a new quantitative chemical-genetic interaction mapping approach to evaluate drug sensitivity or resistance in isogenic cell lines. Performing a high-throughput screen with isogenic cell lines allowed the researchers to explore the impact of a panel of emerging and established drugs on cells overexpressing a single cancer-associated gene in isolation.

  7. Chemical signals might mediate interactions between females and juveniles of Latrodectus geometricus (Araneae: Theridiidae).

    Science.gov (United States)

    Guimarães, Ingrid de Carvalho; Cardoso, Claudia Andrea Lima; Lima, Sandro Marcio; Andrade, Luis Humberto da Cunha; Antonialli Junior, William Fernnando

    2016-05-01

    Studies related to communication on spiders show that, as in other invertebrates, the interactions between conspecifics are also made through chemical signals. Therefore, in order to assess whether the composition of cuticular compounds might be involved in interactions that occur during the days after the emergence of juveniles in Latrodectus geometricus, we conducted behavioral and cuticular chemical profiles analysis of females and juveniles of different ages. The results show that females, regardless of their reproductive state, tolerate juveniles of other females with up to 40 days post-emergence and attack juveniles of 80 days post-emergence. Cuticlar chemical analysis shows that while the profile of juveniles is similar to adult's profile, they can remain in the web without being confused with threat or prey. Also, cuticular chemical profiles vary between different populations probably due to genetic and environmental differences or similarities between them. Finally, females in incubation period are able to detect the presence of eggs within any egg sac, but cannot distinguish egg sacs produced by conspecifics from the ones they had produced.

  8. Predicting metabolic pathways of small molecules and enzymes based on interaction information of chemicals and proteins.

    Science.gov (United States)

    Gao, Yu-Fei; Chen, Lei; Cai, Yu-Dong; Feng, Kai-Yan; Huang, Tao; Jiang, Yang

    2012-01-01

    Metabolic pathway analysis, one of the most important fields in biochemistry, is pivotal to understanding the maintenance and modulation of the functions of an organism. Good comprehension of metabolic pathways is critical to understanding the mechanisms of some fundamental biological processes. Given a small molecule or an enzyme, how may one identify the metabolic pathways in which it may participate? Answering such a question is a first important step in understanding a metabolic pathway system. By utilizing the information provided by chemical-chemical interactions, chemical-protein interactions, and protein-protein interactions, a novel method was proposed by which to allocate small molecules and enzymes to 11 major classes of metabolic pathways. A benchmark dataset consisting of 3,348 small molecules and 654 enzymes of yeast was constructed to test the method. It was observed that the first order prediction accuracy evaluated by the jackknife test was 79.56% in identifying the small molecules and enzymes in a benchmark dataset. Our method may become a useful vehicle in predicting the metabolic pathways of small molecules and enzymes, providing a basis for some further analysis of the pathway systems.

  9. Exploring site-specific chemical interactions at surfaces: a case study on highly ordered pyrolytic graphite

    Science.gov (United States)

    Dagdeviren, Omur E.; Götzen, Jan; Altman, Eric I.; Schwarz, Udo D.

    2016-12-01

    A material’s ability to interact with approaching matter is governed by the structural and chemical nature of its surfaces. Tailoring surfaces to meet specific needs requires developing an understanding of the underlying fundamental principles that determine a surface’s reactivity. A particularly insightful case occurs when the surface site exhibiting the strongest attraction changes with distance. To study this issue, combined noncontact atomic force microscopy and scanning tunneling microscopy experiments have been carried out, where the evolution of the local chemical interaction with distance leads to a contrast reversal in the force channel. Using highly ordered pyrolytic graphite surfaces and metallic probe tips as a model system, we find that at larger tip-sample distances, carbon atoms exhibit stronger attractions than hollow sites while upon further approach, hollow sites become energetically more favorable. For the tunneling current that is recorded at large tip-sample separations during acquisition of a constant-force image, the contrast is dominated by the changes in tip-sample distance required to hold the force constant (‘cross-talk’) at smaller separations the contrast turns into a convolution of this cross-talk and the local density of states. Analysis shows that the basic factors influencing the force channel contrast reversal are locally varying decay lengths and an onset of repulsive forces that occurs for distinct surface sites at different tip-sample distances. These findings highlight the importance of tip-sample distance when comparing the relative strength of site-specific chemical interactions.

  10. Interactions among Carbon Dioxide, Heat, and Chemical Lures in Attracting the Bed Bug, Cimex lectularius L. (Hemiptera: Cimicidae

    Directory of Open Access Journals (Sweden)

    Narinderpal Singh

    2012-01-01

    Full Text Available Commercial bed bug (Cimex lectularius L. monitors incorporating carbon dioxide (CO2, heat, and chemical lures are being used for detecting bed bugs; however, there are few reported studies on the effectiveness of chemical lures in bed bug monitors and the interactions among chemical lure, CO2, and heat. We screened 12 chemicals for their attraction to bed bugs and evaluated interactions among chemical lures, CO2, and heat. The chemical lure mixture consisting of nonanal, 1-octen-3-ol, spearmint oil, and coriander Egyptian oil was found to be most attractive to bed bugs and significantly increased the trap catches in laboratory bioassays. Adding this chemical lure mixture when CO2 was present increased the trap catches compared with traps baited with CO2 alone, whereas adding heat did not significantly increase trap catches when CO2 was present. Results suggest a combination of chemical lure and CO2 is essential for designing effective bed bug monitors.

  11. Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu; Cui, Qiang, E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706 (United States); Elstner, Marcus [Theoretische Chemische Biologie, Universität Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany)

    2015-08-28

    Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.

  12. A thermodynamic framework for thermo-chemo-elastic interactions in chemically active materials

    Science.gov (United States)

    Zhang, XiaoLong; Zhong, Zheng

    2017-08-01

    In this paper, a general thermodynamic framework is developed to describe the thermo-chemo-mechanical interactions in elastic solids undergoing mechanical deformation, imbibition of diffusive chemical species, chemical reactions and heat exchanges. Fully coupled constitutive relations and evolving laws for irreversible fluxes are provided based on entropy imbalance and stoichiometry that governs reactions. The framework manifests itself with a special feature that the change of Helmholtz free energy is attributed to separate contributions of the diffusion-swelling process and chemical reaction-dilation process. Both the extent of reaction and the concentrations of diffusive species are taken as independent state variables, which describe the reaction-activated responses with underlying variation of microstructures and properties of a material in an explicit way. A specialized isothermal formulation for isotropic materials is proposed that can properly account for volumetric constraints from material incompressibility under chemo-mechanical loadings, in which inhomogeneous deformation is associated with reaction and diffusion under various kinetic time scales. This framework can be easily applied to model the transient volumetric swelling of a solid caused by imbibition of external chemical species and simultaneous chemical dilation arising from reactions between the diffusing species and the solid.

  13. Insights into synergistic interactions in binary mixtures of chemical permeation enhancers for transdermal drug delivery.

    Science.gov (United States)

    Karande, Pankaj; Jain, Amit; Mitragotri, Samir

    2006-09-28

    Chemical permeation enhancers (CPEs) are known to increase skin permeability to therapeutic drugs. Single chemicals, however, offer limited enhancements of skin permeability. Mixtures of chemicals can overcome this limitation owing to their synergistic interactions. However, identification of potent mixtures of chemicals requires screening of a large number of formulations. Discovery of CPE mixtures can be significantly accelerated by identifying patterns that occur in the existing data on CPEs. In this study, we systematically mine through a huge database on skin permeabilizing effect of over 4000 binary formulations generated by high throughput screening and extract general principles that govern the effect of binary combinations of chemicals on skin's barrier properties. Potencies and synergies of these formulations are analyzed to identify the role played by the formulation composition and chemistry. The analysis reveals several intuitive but some largely non-intuitive trends. For example, formulations made from enhancer mixtures are most potent when participating moieties are present in nearly equal fractions. Methyl pyrrolidone, a small molecule, is particularly effective in forming potent and synergistic enhancer formulations, and zwitterionic surfactants are more likely to feature in potent enhancers. Simple but invaluable rules like these will provide guiding principles for designing libraries to further speed up the formulation discovery process.

  14. Chemical milling of Zircaloy tubing to produce integral OD spiral finned tubes (AWBA development program)

    Energy Technology Data Exchange (ETDEWEB)

    Horwood, W.A.

    1982-02-01

    A detailed process description is provided for producing integral spiral fins on the outside surface of Zircaloy nuclear fuel cladding tubes by masking with pressure sensitive tape strips and then chemical milling (pickling) the tube wall between the tape strips to leave the fins in relief. Fins up to 0.020 inch high by 0.05 to 0.12 inch wide were consistently produced on tubes having wall thickness of 0.008 inch or greater after fin pickling. Wall thickness uniformity was excellent. Information is provided on tube surface preparation to maximize tape mask adhesion time during pickling, acid chemistry control to prevent local tube wall thinning near the fin, and pickling techniques to promote uniform material removal. Simple fixture designs are described for quickly and conveniently applying the tape strips to the tube wall in an accurate spiral. 13 figures, 4 tables.

  15. Quasi-chemical approach for adsorption of mixtures with non-additive lateral interactions

    Science.gov (United States)

    Pinto, O. A.; Pasinetti, P. M.; Ramirez-Pastor, A. J.

    2017-01-01

    The statistical thermodynamics of binary mixtures with non-additive lateral interactions was developed on a generalization in the spirit of the lattice-gas model and the classical quasi-chemical approximation (QCA). The traditional assumption of a strictly pairwise additive nearest-neighbors interaction is replaced by a more general one, namely that the bond linking a certain atom with any of its neighbors depends considerably on how many of them are actually present (or absent) on the sites in the first coordination shell of the atom. The total and partial adsorption isotherms are given for both attractive and repulsive lateral interactions between the adsorbed species. Interesting behaviors are observed and discussed in terms of the low-temperature phases formed in the system. Comparisons with Monte Carlo simulations are performed in order to test the validity of the theoretical model.

  16. Analysis of the interaction of phytoestrogens and synthetic chemicals: an in vitro/in vivo comparison.

    Science.gov (United States)

    Charles, Grantley D; Gennings, Chris; Tornesi, Belen; Kan, H Lynn; Zacharewski, Timothy R; Bhaskar Gollapudi, B; Carney, Edward W

    2007-02-01

    In the evaluation of chemical mixture toxicity, it is desirable to develop an evaluation paradigm which incorporates some critical attributes of real world exposures, particularly low dose levels, larger numbers of chemicals, and chemicals from synthetic and natural sources. This study evaluated the impact of low level exposure to a mixture of six synthetic chemicals (SC) under conditions of co-exposure to various levels of plant-derived phytoestrogen (PE) compounds. Estrogenic activity was evaluated using an in vitro human estrogen receptor (ER) transcriptional activation assay and an in vivo immature rat uterotrophic assay. Initially, dose-response curves were characterized for each of the six SCs (methoxyclor, o,p-DDT, octylphenol, bisphenol A, beta-hexachlorocyclohexane, 2,3-bis(4-hydroxyphenyl)-propionitrile) in each of the assays. The six SCs were then combined at equipotent ratios and tested at 5-6 dose levels spanning from very low, sub-threshold levels, to a dose in which every chemical in the mixture was at its individual estrogenic response threshold. The SC mixtures also were tested in the absence or presence of 5-6 different levels of PEs, for a total of 36 (in vitro) or 25 (in vivo) treatment groups. Both in vitro and in vivo, low concentrations of the SC mixture failed to increase estrogenic responses relative to those induced by PEs alone. However, significant increases in response occurred when each chemical in the SC mixture was near or above its individual response threshold. In vitro, interactions between high-doses of SCs and PEs were greater than additive, whereas mixtures of SCs in the absence of PEs interacted in a less than additive fashion. In vivo, the SC and PE mixture responses were consistent with additivity. These data illustrate a novel approach for incorporating key attributes of real world exposures in chemical mixture toxicity assessments, and suggest that chemical mixture toxicity is likely to be of concern only when the mixture

  17. Development of a Chemical Equilibrium Model for a Molten Core-Concrete Interaction Analysis Module

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jae Uk; Lee, Dae Young; Park, Chang Hwan [FNC Technology Co., Yongin (Korea, Republic of)

    2016-10-15

    This molten core could interact with the reactor cavity region which consists of concrete. In this process, components of molten core react with components of concrete through a lot of chemical reactions. As a result, many kinds of gas species are generated and those move up forming rising bubbles into the reactor containment atmosphere. These rising bubbles are the carrier of the many kinds of the aerosols coming from the MCCI (Molten Core Concrete Interaction) layers. To evaluate the amount of the aerosols released from the MCCI layers, the amount of the gas species generated from those layers should be calculated. The chemical equilibrium state originally implies the final state of the multiple chemical reactions; therefore, investigating the equilibrium composition of molten core can be applicable to predict the gas generation status. The most common way for finding the chemical equilibrium state is a minimization of total Gibbs free energy of the system. In this paper, the method to make good guess of initial state is suggested and chemical reaction results are compared with results of CSSI report No 164. Total mass of system and the number of atoms of each element are conserved. The tendency of calculation results is similar with results presented in CSNI Report except a few species. These differences may be caused by absence of Gibbs energy data of the species such as Fe{sub 2}SiO{sub 4}, CaFe{sub 2}O{sub 4}, U(OH){sub 3}, UO(OH), UO{sub 2}(OH), U{sub 3}O{sub 7}, La, Ce.

  18. Chemical Structure-Biological Activity Models for Pharmacophores’ 3D-Interactions

    Directory of Open Access Journals (Sweden)

    Mihai V. Putz

    2016-07-01

    Full Text Available Within medicinal chemistry nowadays, the so-called pharmaco-dynamics seeks for qualitative (for understanding and quantitative (for predicting mechanisms/models by which given chemical structure or series of congeners actively act on biological sites either by focused interaction/therapy or by diffuse/hazardous influence. To this aim, the present review exposes three of the fertile directions in approaching the biological activity by chemical structural causes: the special computing trace of the algebraic structure-activity relationship (SPECTRAL-SAR offering the full analytical counterpart for multi-variate computational regression, the minimal topological difference (MTD as the revived precursor for comparative molecular field analyses (CoMFA and comparative molecular similarity indices analysis (CoMSIA; all of these methods and algorithms were presented, discussed and exemplified on relevant chemical medicinal systems as proton pump inhibitors belonging to the 4-indolyl,2-guanidinothiazole class of derivatives blocking the acid secretion from parietal cells in the stomach, the 1-[(2-hydroxyethoxy-methyl]-6-(phenylthiothymine congeners’ (HEPT ligands antiviral activity against Human Immunodeficiency Virus of first type (HIV-1 and new pharmacophores in treating severe genetic disorders (like depression and psychosis, respectively, all involving 3D pharmacophore interactions.

  19. Chemical Structure-Biological Activity Models for Pharmacophores’ 3D-Interactions

    Science.gov (United States)

    Putz, Mihai V.; Duda-Seiman, Corina; Duda-Seiman, Daniel; Putz, Ana-Maria; Alexandrescu, Iulia; Mernea, Maria; Avram, Speranta

    2016-01-01

    Within medicinal chemistry nowadays, the so-called pharmaco-dynamics seeks for qualitative (for understanding) and quantitative (for predicting) mechanisms/models by which given chemical structure or series of congeners actively act on biological sites either by focused interaction/therapy or by diffuse/hazardous influence. To this aim, the present review exposes three of the fertile directions in approaching the biological activity by chemical structural causes: the special computing trace of the algebraic structure-activity relationship (SPECTRAL-SAR) offering the full analytical counterpart for multi-variate computational regression, the minimal topological difference (MTD) as the revived precursor for comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analysis (CoMSIA); all of these methods and algorithms were presented, discussed and exemplified on relevant chemical medicinal systems as proton pump inhibitors belonging to the 4-indolyl,2-guanidinothiazole class of derivatives blocking the acid secretion from parietal cells in the stomach, the 1-[(2-hydroxyethoxy)-methyl]-6-(phenylthio)thymine congeners’ (HEPT ligands) antiviral activity against Human Immunodeficiency Virus of first type (HIV-1) and new pharmacophores in treating severe genetic disorders (like depression and psychosis), respectively, all involving 3D pharmacophore interactions. PMID:27399692

  20. Application of Coating Technology for Accident Tolerant Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    To commercialize the ATF cladding concepts, various factors are considered, such as safety under normal and accident conditions, economy for the fuel cycle, and developing development challenges, and schedule. From the proposed concepts, it is known that the cladding coating, FeCrAl alloy, and Zr-Mo claddings are considered as a near/mid-term application, whereas the SiC material is considered as a long-term application. Among them, the benefit of cladding coating on Zr-based alloys is the fuel cycle economy regarding the manufacturing, neutron cross section, and high tritium permeation characteristics. However, the challenge of cladding coating on Zr-based alloys is the lower oxidation resistance and mechanical strength at high-temperature than other concepts. Another important point is the adhesion property between the Zr-based alloy and coating materials. As an improved coating technology compared to a previous study, a 3D laser coating technology supplied with Cr powders is considered to make a coated cladding because it is possible to make a coated layer on the tubular cladding surface by controlling the 3-diminational axis. We are systematically studying the laser beam power, inert gas flow, cooling of the cladding tube, and powder control as key points to develop 3D laser coating technology. After Cr-coating on the Zr-based cladding, ring compression and ring tensile tests were performed to evaluate the adhesion property between a coated layer and Zr-based alloy tube at room temperature (RT), and a high-temperature oxidation test was conducted to evaluate the oxidation behavior at 1200 .deg. C of the coated tube samples. A 3D laser coating method supplied with Cr powders was developed to decrease the high-temperature oxidation rate in a steam environment through a systematic study for various coating parameters, and a Cr-coated Zircaloy-4 cladding tube of 100 mm in length to the axial direction can be successfully manufactured.

  1. Experimental Setup for Reflood Quench of Accident Tolerant Fuel Claddings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan; Lee, Kwan Geun; In, Wang Kee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The concept of accident tolerant fuel (ATF) is a solution to suppress the hydrogen generation in loss of coolant accident (LOCA) situation without safety injection, which was the critical incident in the severe accident in the Fukushima. The changes in fuel and cladding materials may cause a significant difference in reactor performance in long term operation. Properties in terms of material science and engineering have been tested and showed promising results. However, numerous tests are still required to ensure the design performance and safety. Thermal hydraulic tests including boiling and quenching are partly confirmed, but not yet complete. We have been establishing the experimental setup to confirm the properties in the terms of thermal hydraulics. Design considerations and preliminary tests are introduced in this paper. An experimental setup to test thermal hydraulic characteristics of new ATF claddings are established and tested. The W heater set inside the cladding is working properly, exceeding 690 W/m linear power with thermocouples and insulating ceramic sheaths inside. The coolant injection control was also working in good conditions. The setup is about to complete and going to simulate quenching behavior of the ATF in the LOCA situation.

  2. Chemical interactions between the present-day Martian atmosphere and surface minerals

    Science.gov (United States)

    Prinn, Ronald; Fegley, Bruce

    1987-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surfaces of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere interactions are important for addressing issues such as chemical weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface material. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible however to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation or the identity of its weathered parent mineral. The enormous advantages of studying Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  3. Quantification of chemical mixture interactions modulating dermal absorption using a multiple membrane fiber array.

    Science.gov (United States)

    Baynes, Ronald E; Xia, Xin Rui; Imran, Mudassar; Riviere, Jim E

    2008-03-01

    Dermal exposures to chemical mixtures can potentially increase or decrease systemic bioavailability of toxicants in the mixture. Changes in dermal permeability can be attributed to changes in physicochemical interactions between the mixture, the skin, and the solute of interest. These physicochemical interactions can be described as changes in system coefficients associated with molecular descriptors described by Abraham's linear solvation energy relationship (LSER). This study evaluated the effects of chemical mixtures containing either a solvent (ethanol) or a surfactant (sodium lauryl sulfate, SLS) on solute permeability and partitioning by quantifying changes in system coefficients in skin and a three-membrane-coated fiber (MCF) system, respectively. Regression analysis demonstrated that changes in system coefficients in skin were strongly correlated ( R2 = 0.89-0.98) to changes in system coefficients in the three-membrane MCF array with mixtures containing either 1% SLS or 50% ethanol. The PDMS fiber appeared to play a significant role (R2 = 0.84-0.85) in the MCF array in predicting changes in solute permeability, while the WAX fiber appeared to contribute less (R2 = 0.59-0.77) to the array than the other two fibers. On the basis of changes in system coefficients that are part of a LSER, these experiments were able to link physicochemical interactions in the MCF with those interactions in skin when either system is exposed to 1% SLS or 50% ethanol. These experiments further demonstrated the utility of a MCF array to adequately predict changes in dermal permeability when skin is exposed to mixtures containing either a surfactant or a solvent and provide some insight into the nature of the physiochemical interactions that modulate dermal absorptions.

  4. A systematic prediction of multiple drug-target interactions from chemical, genomic, and pharmacological data.

    Directory of Open Access Journals (Sweden)

    Hua Yu

    Full Text Available In silico prediction of drug-target interactions from heterogeneous biological data can advance our system-level search for drug molecules and therapeutic targets, which efforts have not yet reached full fruition. In this work, we report a systematic approach that efficiently integrates the chemical, genomic, and pharmacological information for drug targeting and discovery on a large scale, based on two powerful methods of Random Forest (RF and Support Vector Machine (SVM. The performance of the derived models was evaluated and verified with internally five-fold cross-validation and four external independent validations. The optimal models show impressive performance of prediction for drug-target interactions, with a concordance of 82.83%, a sensitivity of 81.33%, and a specificity of 93.62%, respectively. The consistence of the performances of the RF and SVM models demonstrates the reliability and robustness of the obtained models. In addition, the validated models were employed to systematically predict known/unknown drugs and targets involving the enzymes, ion channels, GPCRs, and nuclear receptors, which can be further mapped to functional ontologies such as target-disease associations and target-target interaction networks. This approach is expected to help fill the existing gap between chemical genomics and network pharmacology and thus accelerate the drug discovery processes.

  5. Perspective: Found in translation: Quantum chemical tools for grasping non-covalent interactions

    Science.gov (United States)

    Pastorczak, Ewa; Corminboeuf, Clémence

    2017-03-01

    Today's quantum chemistry methods are extremely powerful but rely upon complex quantities such as the massively multidimensional wavefunction or even the simpler electron density. Consequently, chemical insight and a chemist's intuition are often lost in this complexity leaving the results obtained difficult to rationalize. To handle this overabundance of information, computational chemists have developed tools and methodologies that assist in composing a more intuitive picture that permits better understanding of the intricacies of chemical behavior. In particular, the fundamental comprehension of phenomena governed by non-covalent interactions is not easily achieved in terms of either the total wavefunction or the total electron density, but can be accomplished using more informative quantities. This perspective provides an overview of these tools and methods that have been specifically developed or used to analyze, identify, quantify, and visualize non-covalent interactions. These include the quantitative energy decomposition analysis schemes and the more qualitative class of approaches such as the Non-covalent Interaction index, the Density Overlap Region Indicator, or quantum theory of atoms in molecules. Aside from the enhanced knowledge gained from these schemes, their strengths, limitations, as well as a roadmap for expanding their capabilities are emphasized.

  6. Chemical interactions and gel properties of black carp actomyosin affected by MTGase and their relationships.

    Science.gov (United States)

    Jia, Dan; Huang, Qilin; Xiong, Shanbai

    2016-04-01

    Partial least squares regression (PLSR) was applied to evaluate and correlate chemical interactions (-NH2 content, S-S bonds, four non-covalent interactions) with gel properties (dynamic rheological properties and cooking loss (CL)) of black carp actomyosin affected by microbial transglutaminase (MTGase) at suwari and kamaboko stages. The G' and CL were significantly enhanced by MTGase and their values in kamaboko gels were higher than those in suwari gels at the same MTGase concentration. The γ-carboxyamide and amino cross-links, catalyzed by MTGase, were constructed at suwari stage and contributed to the network formation, while disulfide bonds were formed not only in suwari gels but also in kamaboko gels, further enhancing the gel network. PLSR analysis revealed that 86.6-90.3% of the variation of G' and 91.8-94.4% of the variation of CL were best explained by chemical interactions. G' mainly depended on covalent cross-links and gave positive correlation. CL was positively correlated with covalent cross-links, but negatively related to non-covalent bonds, indicating that covalent bonds promoted water extrusion, whereas non-covalent bonds were beneficial for water-holding.

  7. Galaxy pairs in cosmological simulations: effects of interactions on colours and chemical abundances

    CERN Document Server

    Perez, M J; Lambas, D G; Scannapieco, C; Tissera, P B; Lambas, Diego G.; Rossi, Maria E. De; Scannapieco, Cecilia; Tissera, Patricia B.

    2006-01-01

    We perform an statistical analysis of galaxies in pairs in a Lambda-CDM scenario by using the chemical GADGET-2 of Scannapieco et al. (2005) in order to study the effects of galaxy interactions on colours and metallicities. We find that galaxy-galaxy interactions can produce a bimodal colour distribution with galaxies with significant recent star formation activity contributing mainly to blue colours. In the simulations, the colours and the fractions of recently formed stars of galaxies in pairs depend on environment more strongly than those of galaxies without a close companion, suggesting that interactions play an important role in galaxy evolution. If the metallicity of the stellar populations is used as the chemical indicator, we find that the simulated galaxies determine luminosity-metallicity and stellar mass-metallicity relations which do not depend on the presence of a close companion. However, in the case of the luminosity-metallicity relation, at a given level of enrichment, we detect a systematic d...

  8. Interaction of cationic dye/surfactants with Klebsiella K18 capsular polysaccharides: Physico-chemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Ranendu Kumar, E-mail: rknath1959@gmail.com [Department of Chemistry, Tripura University, Suryamaninagar, Tripura-799130 (India); Singh, Th. Charanjit [Department of Chemistry, D.D.M. College, Khowai, Tripura-799 202 (India); Dasgupta, Satwati [Department of Chemistry, Tripura University, Suryamaninagar, Tripura-799130 (India); Mitra, Asish [Department of Chemistry, MBB College, Agartala, Tripura-799001 (India); Panda, Amiya Kumar [Department of Chemistry, University of North Bengal, P.O. North Bengal University, Dt: Darjeeling, West Bengal-734013 (India)

    2010-05-10

    Physico-chemical studies on the interaction of capsular polysaccharide (SPS) isolated from Klebsiella K18, with cationic dyes and surfactants have been reported. SPS is an integral component of gram-negative bacteria and having glucuronic acid as the potential anionic site, induced strong metachromasy (blue shift {approx} 110 nm) in the cationic dye pinacyanol chloride (PCYN). Reversal of metachromasy was observed upon addition of co-solvents which provides a qualitative measurement of stability and nature of metachromatic compound associated with PCYN-SPS interaction. Thermodynamic parameters such as association constant, changes in free energy, enthalpy and entropy of dye-polymer interaction, were evaluated which revealed the nature of interaction. Studies on fluorescence quenching of acridine orange (AO) was also performed. The interaction of SPS with cationic and cationic-non-ionic mixed surfactant systems have been studied by turbidimetry, spectrophotometry, spectrofluorometry and viscosity measurements. The studies could provide an understanding on the effects of the surfactants on binding with the polymer. The binding was found to be electrostatic in origin and also hydrophobic in nature to a certain extent.

  9. Quantum-chemical examination of interaction of cytostatic-fluorouracil with deoxyribonucleic acids

    Science.gov (United States)

    Yuldasheva, Gulnara; Zhidomirov, Georgii M.

    Within the framework of semiempirical method of quantum chemical PM3, the possibility of formation of paired stack structures under interaction of fluorouracil with pyrimidine and purine nitrogenous bases of nucleotides has been examined. Possible mechanism of transformation of 2-deoxyuridine-5-monophosphate into metabolite-5-fluorin-2-deoxyuridine-5-monophosphate has been given. The calculations that were made allow to suppose that biotransformation of 5-FU in 5-fluorin-2-deoxyuridine-5-monophosphate, most likely, is carried out not in free nucleotides, but in the structure of DNA in two nucleotide triplets UUC and UGU, including the case when directly two nucleotides of deoxyuridine monophosphate, are transformed into 5-fluorin-2-deoxyuridine-5-monophosphate. Cytostatic ability of 5-FU is increased by its capacity to be selectively embedded into nucleotide triplets creating new chemical compounds that violate matrix RNA formation and accordingly violate protein synthesis.0

  10. Prediction of eye irritation from organic chemicals using membrane-interaction QSAR analysis.

    Science.gov (United States)

    Kulkarni, A; Hopfinger, A J; Osborne, R; Bruner, L H; Thompson, E D

    2001-02-01

    Eye irritation potency of a compound or mixture has traditionally been evaluated using the Draize rabbit-eye test (Draize et al., 1944). In order to aid predictions of eye irritation and to explore possible corresponding mechanisms of eye irritation, a methodology termed "membrane-interaction QSAR analysis" (MI-QSAR) has been developed (Kulkarni and Hopfinger 1999). A set of Draize eye-irritation data established by the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) (Bagley et al., 1992) was used as a structurally diverse training set in an MI-QSAR analysis. Significant QSAR models were constructed based primarily upon aqueous solvation-free energy of the solute and the strength of solute binding to a model phospholipid (DMPC) monolayer. The results demonstrate that inclusion of parameters to model membrane interactions of potentially irritating chemicals provides significantly better predictions of eye irritation for structurally diverse compounds than does modeling based solely on physiochemical properties of chemicals. The specific MI-QSAR models reported here are, in fact, close to the upper limit in both significance and robustness that can be expected for the variability inherent to the eye-irritation scores of the ECETOC training set. The MI-QSAR models can be used with high reliability to classify compounds of low- and high-predicted eye irritation scores. Thus, the models offer the opportunity to reduce animal testing for compounds predicted to fall into these two extreme eye-irritation score sets. The MI-QSAR paradigm may also be applicable to other toxicological endpoints, such as skin irritation, where interactions with cellular membranes are likely.

  11. How Soil Organic Matter Composition Controls Hexachlorobenzene-Soil-Interactions: Adsorption Isotherms and Quantum Chemical Modelling

    CERN Document Server

    Ahmed, Ashour; Kühn, Oliver

    2013-01-01

    Hazardous persistent organic pollutants (POPs) interact in soil with the soil organic matter (SOM) but this interaction is insufficiently understood at the molecular level. We investigated the adsorption of hexachlorobenzene (HCB) on soil samples with systematically modified SOM. These samples included the original soil, the soil modified by adding a hot water extract (HWE) fraction (soil+3 HWE and soil+6 HWE), and the pyrolyzed soil. The SOM contents increased in the order pyrolyzed soil < original soil < soil+3 HWE < soil+6 HWE. For the latter three samples this order was also valid for the HCB adsorption. The pyrolyzed soil adsorbed more HCB than the other samples at low initial concentrations, but at higher concentrations the HCB adsorption became weaker than in the samples with HWE addition. This adsorption behaviour combined with the differences in the chemical composition between the soil samples suggested that alkylated aromatic, phenol, and lignin monomer compounds contributed most to the HC...

  12. Curvature effects upon interactions of polymer-grafted nanoparticles in chemically identical polymer matrices.

    Science.gov (United States)

    Trombly, David M; Ganesan, Venkat

    2010-10-21

    We study the interactions between polymer-grafted nanoparticles immersed in a chemically identical polymer melt using a numerical implementation of polymer mean-field theory. We focus on the interpenetration width between the grafted and free chains and its relationship to the polymer-mediated interparticle interactions. To this end, we quantify the interpenetration width as a function of particle curvature, grafting density, and the relative molecular weights of the grafted and free chains. We show the onset of wetting and dewetting as a function of these quantities and explain our results through simple scaling arguments to include the effects of curvature. Subsequently, we show that the interparticle potentials correlate quantitatively with the trends displayed by the interpenetration widths.

  13. O/S-1/ interactions - The product channels. [collisional electron quenching and chemical reaction pathway frequencies

    Science.gov (United States)

    Slanger, T. G.; Black, G.

    1978-01-01

    The first measurements are reported of the reaction pathways for the interaction between oxygen atoms in the 4.19 eV S-1 state, and four molecules, N2O, CO2, H2O, and NO. Distinction is made between three possible paths - quenching to O(D-1), quenching to O(P-3), and chemical reaction. With N2O, the most reasonable interpretation of the data indicates that there no reaction, in sharp contrast with the interaction between O(D-1) and N2O, which proceeds entirely by reaction. Similarly, there is no reaction with CO2. With H2O, the reactive pathway is the dominant one, although electronic quenching is not negligible. With NO, O(D-1) is the preferred product.

  14. Development of a chemically defined medium for studying foodborne bacterial-fungal interactions

    DEFF Research Database (Denmark)

    Aunsbjerg, Stina Dissing; Honoré, Anders Hans; Vogensen, Finn Kvist

    2015-01-01

    There is a growing interest for using natural preservatives in the food and dairy industries including the application of bacterial cultures to inhibit fungal spoilage. Several antifungal metabolites from bacteria have been identified, but their relative importance has been difficult to establish....... In dynamic systems such as fermented milk products, the complexity of the food matrix affects detection, identification and quantification of antifungal metabolites, and thereby the understanding of the bacterial-fungal interactions. To ease the identification and quantification of bacterial metabolites (as...... judged by ultra-performance liquid chromatography/mass spectrometry) a chemically defined interaction medium (CDIM) was developed. The medium supported growth of antifungal cultures such as Lactobacillus paracasei and Propionibacterium freudenreichii, as well as spoilage moulds and yeasts isolated from...

  15. Plant chemical defense indirectly mediates aphid performance via interactions with tending ants.

    Science.gov (United States)

    Züst, Tobias; Agrawal, Anurag A

    2017-03-01

    The benefits of mutualistic interactions are often highly context dependent. We studied the interaction between the milkweed aphid Aphis asclepiadis and a tending ant, Formica podzolica. Although this interaction is generally considered beneficial, variation in plant genotype may alter it from mutualistic to antagonistic. Here we link the shift in strength and relative benefit of the ant-aphid interaction to plant genotypic variation in the production of cardenolides, a class of toxic defensive chemicals. In a field experiment with highly variable genotypes of the common milkweed (Asclepias syriaca), we show that plant cardenolides, especially polar forms, are ingested by aphids and excreted in honeydew proportionally to plant concentrations without directly affecting aphid performance. Ants consume honeydew, and aphids that excreted high amounts of cardenolides received fewer ant visits, which in turn reduced aphid survival. On at least some plant genotypes, aphid numbers per plant were reduced in the presence of ants to levels lower than in corresponding ant-exclusion treatments, suggesting antagonistic ant behavior. Although cardenolides appear ineffective as direct plant defenses against aphids, the multi-trophic context reveals an ant-mediated negative indirect effect on aphid performance and population dynamics. © 2016 by the Ecological Society of America.

  16. Interaction of chemical species with biological regulation of the metabolism of essential trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, W. [Center of Life and Food Sciences, Technische Univ. Muenchen, Freising (Germany)

    2002-02-01

    Variations in the chemical speciation of dietary trace elements can result in the provision of different amounts of these micronutrients to the organism and might thus induce interactions with trace-element metabolism. The chemical species of Zn, Fe, Cu, and Mn can interact with other components of the diet even before reaching the site of absorption, e.g. by formation of poorly soluble complexes with phytic acid. This might considerably modify the amount of metabolically available trace elements; differences between absorptive capacity per se toward dietary species seems to be less important. Homeostasis usually limits the quantities of Zn, Fe, Cu, and Mn transported from the gut into the organism, and differences between dietary species are largely eliminated at this step. There is no homeostatic control of absorption of Se and I, and organisms seem to be passively exposed to influx of these micronutrients irrespective of dietary speciation. Inside the organism the trace elements are usually converted into a metabolically recognizable form, channeled into their biological functions, or submitted to homeostatically controlled excretion. Some dietary species can, however, be absorbed as intact compounds. As long as the respective quantities of trace elements are not released from their carriers, they are not recognized properly by trace element metabolism and might induce tissue accumulation, irrespective of homeostatic control. (orig.)

  17. A systematic identification of multiple toxin-target interactions based on chemical, genomic and toxicological data.

    Science.gov (United States)

    Zhou, Wei; Huang, Chao; Li, Yan; Duan, Jinyou; Wang, Yonghua; Yang, Ling

    2013-02-01

    Although the assessment of toxicity of various agents, -omics (genomic, proteomic, metabolomic, etc.) data has been accumulated largely, the acquirement of toxicity information of variety of molecules through experimental methods still remains a difficult task. Presently, a systems toxicology approach that integrates massive diverse chemical, genomic and toxicological information was developed for prediction of the toxin targets and their related networks. The procedures are: (1) by use of two powerful statistical methods, i.e., support vector machine (SVM) and random forest (RF), a systemic model for prediction of multiple toxin-target interactions using the extracted chemical and genomic features has been developed with its reliability and robustness estimated. And the qualitative classification of targets according to the phenotypic diseases has been taken into account to further uncover the biological meaning of the targets, as well as to validate the robustness of the in silico models. (2) Based on the predicted toxin-target interactions, a genome-scale toxin-target-disease network exampled by cardiovascular disease is generated. (3) A topological analysis of the network is carried out to identify those targets that are most susceptible in human to topical agents including the most critical toxins, as well as to uncover both the toxin-specific mechanisms and pathways. The methodologies presented herein for systems toxicology will make drug development, toxin environmental risk assessment more efficient, acceptable and cost-effective.

  18. Interactions Between Industrial Yeasts and Chemical Contaminants in Grape Juice Affect Wine Composition Profile

    Directory of Open Access Journals (Sweden)

    Etjen Bizaj

    2014-01-01

    Full Text Available The interaction between four industrial wine yeast strains and grape juice chemical contaminants during alcoholic fermentation was studied. Industrial strains of Saccharomyces cerevisiae (AWRI 0838, S. cerevisiae mutant with low H2S production phenotype (AWRI 1640, interspecies hybrid of S. cerevisiae and S. kudriavzevii (AWRI 1539 and a hybrid of AWRI 1640 and AWRI 1539 (AWRI 1810 were exposed separately to fungicides pyrimethanil (Pyr, 10 mg/L and fenhexamid (Fhx, 10 mg/L, as well as to the most common toxin produced by moulds on grapes, ochratoxin A (OTA, 5 μg/L, during alcoholic fermentation of Vitis vinifera L. cv. Sauvignon blanc juice. Contaminants were found to strongly impair fermentation performance and metabolic activity of all yeast strains studied. The chemical profile of wine was analyzed by HPLC (volatile acidity, concentrations of ethanol, fructose, glucose, glycerol and organic acids and the aromatic profile was analyzed using a stable isotope dilution technique using GC/MS (ethyl esters, acetates and aromatic alcohols and Kitagawa tubes (H2S. The chemical composition of wine with added contaminants was in all cases significantly different from the control. Of particular note is that the quantity of aromatic compounds produced by yeast was significantly lower. Yeast’s capacity to remove contaminants from wine at the end of the alcoholic fermentation, and after extended contact (7 days was determined. All the strains were able to remove contaminants from the media, moreover, after extended contact, the concentration of contaminants was in most cases lower.

  19. The complex interaction between marine debris and toxic chemicals in the ocean.

    Science.gov (United States)

    Engler, Richard E

    2012-11-20

    Marine debris, especially plastic debris, is widely recognized as a global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.

  20. Chemical Atmosphere-Snow-Sea Ice Interactions: defining future research in the field, lab and modeling

    Science.gov (United States)

    Frey, Markus

    2015-04-01

    The air-snow-sea ice system plays an important role in the global cycling of nitrogen, halogens, trace metals or carbon, including greenhouse gases (e.g. CO2 air-sea flux), and therefore influences also climate. Its impact on atmospheric composition is illustrated for example by dramatic ozone and mercury depletion events which occur within or close to the sea ice zone (SIZ) mostly during polar spring and are catalysed by halogens released from SIZ ice, snow or aerosol. Recent field campaigns in the high Arctic (e.g. BROMEX, OASIS) and Antarctic (Weddell sea cruises) highlight the importance of snow on sea ice as a chemical reservoir and reactor, even during polar night. However, many processes, participating chemical species and their interactions are still poorly understood and/or lack any representation in current models. Furthermore, recent lab studies provide a lot of detail on the chemical environment and processes but need to be integrated much better to improve our understanding of a rapidly changing natural environment. During a 3-day workshop held in Cambridge/UK in October 2013 more than 60 scientists from 15 countries who work on the physics, chemistry or biology of the atmosphere-snow-sea ice system discussed research status and challenges, which need to be addressed in the near future. In this presentation I will give a summary of the main research questions identified during this workshop as well as ways forward to answer them through a community-based interdisciplinary approach.

  1. Tribochemical interaction between nanoparticles and surfaces of selective layer during chemical mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, Filip, E-mail: filip@meca.omtr.pub.ro [Polytechnic University of Bucharest, Department of Machine Elements and Tribology (Romania)

    2013-11-15

    Nanoparticles have been widely used in polish slurries such as those in the chemical mechanical polishing (CMP) process. For understanding the mechanisms of CMP, an atomic force microscope (AFM) is used to characterize polished surfaces of selective layers, after a set of polishing experiments. To optimize the CMP polishing process, one needs to get information on the interaction between the nano-abrasive slurry nanoparticles and the surface of selective layer being polished. The slurry used in CMP process of the solid surfaces is slurry with large nanoparticle size colloidal silica sol nano-abrasives. Silica sol nano-abrasives with large nanoparticle are prepared and characterized by transmission electron microscopy, particles colloidal size, and Zeta potential in this paper. The movement of nanoparticles in liquid and the interaction between nanoparticles and solid surfaces coating with selective layer are very important to obtain an atomic alloy smooth surface in the CMP process. We investigate the nanoparticle adhesion and removal processes during CMP and post-CMP cleaning. The mechanical interaction between nanoparticles and the wafer surface was studied using a microcontact wear model. This model considers the nanoparticle effects between the polishing interfaces during load balancing. Experimental results on polishing and cleaning are compared with numerical analysis. This paper suggests that during post-CMP cleaning, a combined effort in chemical and mechanical interaction (tribochemical interactions) would be effective in removal of small nanoparticles during cleaning. For large nanoparticles, more mechanical forces would be more effective. CMP results show that the removal rate has been improved to 367 nm/min and root mean square (RMS) of roughness has been reduced from 4.4 to 0.80 nm. Also, the results show that the silica sol nano-abrasives about 100 nm are of higher stability (Zeta potential is −65 mV) and narrow distribution of nanoparticle

  2. Dominance from the perspective of gene-gene and gene-chemical interactions.

    Science.gov (United States)

    Gladki, Arkadiusz; Zielenkiewicz, Piotr; Kaczanowski, Szymon

    2016-02-01

    In this study, we used genetic interaction (GI) and gene-chemical interaction (GCI) data to compare mutations with different dominance phenotypes. Our analysis focused primarily on Saccharomyces cerevisiae, where haploinsufficient genes (HI; genes with dominant loss-of-function mutations) were found to be participating in gene expression processes, namely, the translation and regulation of gene transcription. Non-ribosomal HI genes (mainly regulators of gene transcription) were found to have more GIs and GCIs than haplosufficient (HS) genes. Several properties seem to lead to the enrichment of interactions, most notably, the following: importance, pleiotropy, gene expression level and gene expression variation. Importantly, after these properties were appropriately considered in the analysis, the correlation between dominance and GI/GCI degrees was still observed. Strikingly, for the GCIs of heterozygous strains, haploinsufficiency was the only property significantly correlated with the number of GCIs. We found ribosomal HI genes to be depleted in GIs/GCIs. This finding can be explained by their high variation in gene expression under different genetic backgrounds and environmental conditions. We observed the same distributions of GIs among non-ribosomal HI, ribosomal HI and HS genes in three other species: Schizosaccharomyces pombe, Drosophila melanogaster and Homo sapiens. One potentially interesting exception was the lack of significant differences in the degree of GIs between non-ribosomal HI and HS genes in Schizosaccharomyces pombe.

  3. Chemical modification of SWNT alters in vitro cell-SWNT interactions.

    Science.gov (United States)

    Nimmagadda, Aditya; Thurston, Karen; Nollert, Matthias U; McFetridge, Peter S

    2006-03-01

    Single-walled carbon nanotubes (SWNT) have been the focus of considerable attention as a material with extraordinary mechanical and electrical properties. SWNT have been proposed in a number of biomedical applications, including neural, bone, and dental tissue engineering. In these applications, it is clear that surrounding tissues will come into surface contact with SWNT composites, and compatibility between SWNT and host cells must be addressed. This investigation describes the gross physical and chemical effects of different SWNT preparations on in vitro cell viability and metabolic activity. Three different SWNT preparations were analyzed: as purchased (AP-NT), purified (PUR-NT), and functionalized with glucosamine (GA-NT), over concentrations of 0.001-1.0% (wt/vol). With the exception of the lowest SWNT concentrations, increasing concentrations of SWNT resulted in a decrease of cell viability, which was dependent on SWNT preparation. The metabolic activity of 3T3 cells was also dependent on SWNT preparation and concentration. These investigations have shown that these SWNT preparations have significant effects on in vitro cellular function that cannot be attributed to one factor alone, but are more likely the result of several unfavorable interactions. Effects, such as destabilizing the cell membrane, soluble toxic contaminants, and limitations in mass transfer as the SWNT coalesce into sheets, may all play a role in these interactions. Using comprehensive purification processes and modifying the NT-surface chemistry to introduce functional groups or reduce hydrophobicity or both, these interactions can be significantly improved.

  4. CHEMICALS

    CERN Document Server

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  5. Analyses on the U-Mo/Al Chemical Interaction and the Effects of Diffusion Barrier Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Kim, Woo Jeong; Cho, Woo Hyung; Jeong, Yong Jin; Lee, Yoon Sang; Park, Jong Man; Kim, Chang Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    While many HEU-fueled research reactors have been converted by adopting LEU U{sub 3}Si{sub 2} fuel in harmony with the Reduced Enrichment for Research and Test Reactors (RERTR) program, some high performance research reactors still need the development of advanced fuels with higher uranium densities. Currently, gamma-phase U-Mo alloys are considered promising candidates to be used as high uranium density fuel for the high performance reactors. For the production of UMo alloy powder, the centrifugal atomization technology developed by KAERI has been considered the most promising way because of high yield production and excellent powder quality when compared with other possible methods such as grinding, machining or hydriding-dehydriding. However, severe pore formation associated with an extensive interaction between the U-Mo and Al matrix, although the irradiation performance of U-Mo itself showed most stable, delay the fuel qualification of UMo fuel for high performance research reactors. Because the reaction products, i.e. uranium aluminides (UAlx), is less dense than the mixed reactants, the volume of the fuel meat increases after formation of interaction layer(IL). In addition to the impact on the swelling performance, the reaction layers between the U-Mo and Al matrix induces a degradation of the thermal conductivities of the U-Mo/Al dispersion fuels. The chemical interaction between the U-Mo and Al matrix are analyzed in this study to find remedies to reduce the growth of the interaction layers during irradiation. In addition, various coating technologies for the formation of diffusion barriers on U-Mo particles are proposed as a result of the analyses

  6. Interactions of zearalenone with native and chemically modified cyclodextrins and their potential utilization.

    Science.gov (United States)

    Poór, Miklós; Kunsági-Máté, Sándor; Sali, Nikolett; Kőszegi, Tamás; Szente, Lajos; Peles-Lemli, Beáta

    2015-10-01

    Zearalenone (ZEA) is a widespread xenoestrogenic mycotoxin produced by several Fusarium species. ZEA can cause reproductive disorders in farm animals and hyperoestrogenic syndromes in humans; therefore, development of more sensitive analytical methods (to quantify the mycotoxin) as well as strategies for prevention of its toxic impacts is highly important. In this study, the interactions of ZEA with native and chemically modified cyclodextrins (CDs) were investigated using fluorescence spectroscopy. Furthermore, in vitro experiments on liver cells were also performed to test the potential effect of CDs on toxin uptake. Our results demonstrate that ZEA forms stable complexes with CDs (logK values are approximately 3.7-4.7) resulting in the considerable elevation of its fluorescence signal. In addition, some of the CDs show ability to inhibit the cellular uptake of ZEA, suggesting their potential suitability to develop new CD-based preventive/detoxification strategies against ZEA in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Parameter-free determination of actual temperature at chemical freeze-out in nuclear interactions

    Science.gov (United States)

    Panagiotou, A. D.; Mavromanolakis, G.; Tzoulis, J.

    1995-07-01

    We propose a method to determine the actual temperature at chemical freeze-out in relativistic nucleus-nucleus collisions, using the experimental μq/T and μs/T values, obtained from strange particle ratios. We employ the Hadron Gas formalism, assuming only local thermal equilibration, to relate the quarkchemical potential and temperature. This relation constrains the allowed values of μq/T, μs/T and T, enabling the determination of the actual temperature. Comparison of the inverse slope parameter of the mT-distributions with the actual temperature determines the transverse flow velocity of the fireball matter. Knowledge of these quantities is essential in determining the EoS of nuclear matter and in evaluating interactions with regard to a possible phase transition to QGP.

  8. Electronic inhomogeneities in graphene: the role of the substrate interaction and chemical doping

    Directory of Open Access Journals (Sweden)

    G. Rubio-Bollinger

    2012-09-01

    Full Text Available We probe the local inhomogeneities of the electronicproperties of graphene at the nanoscale usingscanning probe microscopy techniques. First, wefocus on the study of the electronic inhomogeneitiescaused by the graphene-substrate interaction ingraphene samples exfoliated on silicon oxide. Wefind that charged impurities, present in the graphenesubstrateinterface, perturb the carrier densitysignificantly and alter the electronic properties ofgraphene. This finding helps to understand theobserved device-to-device variation typically observedin graphene-based electronic devices. Second, weprobe the effect of chemical modification in theelectronic properties of graphene, grown by chemicalvapour deposition on nickel. We find that both thechemisorption of hydrogen and the physisorption ofporphyrin molecules strongly depress theconductance at low bias indicating the opening of abandgap in graphene, paving the way towards thechemical engineering of the electronic properties ofgraphene.

  9. Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids

    Directory of Open Access Journals (Sweden)

    Novak Marc E

    2002-06-01

    Full Text Available Abstract Background Fertilisation of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the US, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. Methods To describe and document adverse effects reported by residents, 48 individuals at ten sites in the US and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, PA. Medical records were reviewed in cases involving hospitalisation or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. Results Affected residents lived within approximately 1 km of land application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately 1 in 4 of 54 individuals were infected, including 2 mortalities (septicaemia, pneumonia. This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is commonly found in the lower human colon, tends to invade irritated or inflamed tissue. Conclusions When assessing public health risks from applying sewage sludges in residential areas, potential interactions of

  10. Adhesion force interactions between cyclopentane hydrate and physically and chemically modified surfaces.

    Science.gov (United States)

    Aman, Zachary M; Sloan, E Dendy; Sum, Amadeu K; Koh, Carolyn A

    2014-12-07

    Interfacial interactions between liquid-solid and solid-solid phases/surfaces are of fundamental importance to the formation of hydrate deposits in oil and gas pipelines. This work establishes the effect of five categories of physical and chemical modification to steel on clathrate hydrate adhesive force: oleamide, graphite, citric acid ester, nonanedithiol, and Rain-X anti-wetting agent. Hydrate adhesive forces were measured using a micromechanical force apparatus, under both dry and water-wet surface conditions. The results show that the graphite coating reduced hydrate-steel adhesion force by 79%, due to an increase in the water wetting angle from 42 ± 8° to 154 ± 7°. Two chemical surface coatings (nonanedithiol and the citric acid ester) induced rapid hydrate growth in the hydrate particles; nonanedithiol increased hydrate adhesive force by 49% from the baseline, while the citric acid ester coating reduced hydrate adhesion force by 98%. This result suggests that crystal growth may enable a strong adhesive pathway between hydrate and other crystalline structures, however this effect may be negated in cases where water-hydrocarbon interfacial tension is minimised. When a liquid water droplet was placed on the modified steel surfaces, the graphite and citric acid ester became less effective at reducing adhesive force. In pipelines containing a free water phase wetting the steel surface, chemical or physical surface modifications alone may be insufficient to eliminate hydrate deposition risk. In further tests, the citric acid ester reduced hydrate cohesive forces by 50%, suggesting mild activity as a hybrid anti-agglomerant suppressing both hydrate deposition and particle agglomeration. These results demonstrate a new capability to develop polyfunctional surfactants, which simultaneously limit the capability for hydrate particles to aggregate and deposit on the pipeline wall.

  11. Dimorphic placental stress: A repercussion of interaction between endocrine disrupting chemicals (EDCs) and fetal sex.

    Science.gov (United States)

    Sood, Surbhi; Shekhar, Sudhanshu; Santosh, Winkins

    2017-02-01

    Placental homeostasis is critical for fetal development as it determines the health of mother and fetus during pregnancy and in later life. Interestingly even the fetus, in a sexually dimorphic manner, influences the pedantic growth and development of placenta. Although placenta is thought to act as a protective barrier against chemical exposures, certain endocrine disrupting chemicals (EDCs) that are circulating in mother's blood tend to cross placenta. These EDCs have been reported to cause changes in expression levels of certain genes, immunogenic factors and non-coding RNAs such as micro RNA (miRNA) and long non-coding RNA (lncRNA) leading to placental stress. We hypothesize that these changes in placenta occur in a sexually dimorphic manner as a result of interaction between EDC exposure and fetal sex. Therefore, we propose that the ability of placenta to respond and buffer EDC exposure depends on fetal sex and, hence the EDC associated disease susceptibility of one sex differs from the other.

  12. Chemical interaction between polyphenols and a cysteinyl thiol under radical oxidation conditions.

    Science.gov (United States)

    Fujimoto, Aya; Masuda, Toshiya

    2012-05-23

    Chemical interaction between polyphenols and thiols was investigated under radical oxidation conditions using a model cysteinyl thiol derivative, N-benzoylcysteine methyl ester. The radical oxidation was carried out with a stoichiometric amount of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the decreases in the amounts of polyphenols and the thiol were measured by HPLC analysis. Cross-coupling products between various polyphenols and the thiol were examined by LC-MS in reactions that showed decreases in both the polyphenols and the thiol. The LC-MS results indicated that three phenolic acid esters (methyl caffeate, methyl dihydrocaffeate, and methyl protocatechuate) and six flavonoids (kaempferol, myricetin, luteolin, morin, taxifolin, and catechin) gave corresponding thiol adducts, whereas three polyphenols (methyl ferulate, methyl sinapate, and quercetin) gave only dimers or simple oxidation products without thiol substituents. Thiol adducts of the structurally related compounds methyl caffeate and methyl dihydrocaffeate were isolated, and their chemical structures were determined by NMR analysis. The mechanism for the thiol addition was discussed on the basis of the structures of the products.

  13. Interactions between structural and chemical biomimetism in synthetic stem cell niches.

    Science.gov (United States)

    Nava, Michele M; Raimondi, Manuela T; Credi, Caterina; De Marco, Carmela; Turri, Stefano; Cerullo, Giulio; Osellame, Roberto

    2015-01-16

    Advancements in understanding stem cell functions and differentiation are of key importance for the clinical success of stem-cell-based therapies. 3D structural niches fabricated by two-photon polymerization are a powerful platform for controlling stem cell growth and differentiation. In this paper, we investigate the possibility of further controlling stem cell fate by tuning the mechanical properties of such niches through coating with thin layers of biomimetic hyaluronan-based and gelatin-based hydrogels. We first assess the biocompatibility of chemical coatings and then study the interactions between structural and chemical biomimetism on the response of MSCs in terms of proliferation and differentiation. We observed a clear effect of the hydrogel coating on otherwise identical 3D scaffolds. In particular, in gelatin-coated niches we observed a stronger metabolic activity and commitment toward the osteo-chondral lineage with respect to hyaluronan-coated niches. Conversely, a reduction in the homing effect was observed in all the coated niches, especially in gelatin-coated niches. This study demonstrates the feasibility of controlling independently different mechanical cues, in bioengineered stem cell niches, i.e. the 3D scaffold geometry and the surface stiffness. This will allow, on the one hand, understanding their specific role in stem cell proliferation and differentiation and, on the other hand, finely tuning their synergistic effect.

  14. Experimental studies of thermal and chemical interactions between oxide and silicide nuclear fuels with water

    Energy Technology Data Exchange (ETDEWEB)

    farahani, A.A.; Corradini, M.L. [Univ. of Wisconsi, Madison, WI (United States)

    1995-09-01

    Given some transient power/cooling mismatch is a nuclear reactor and its inability to establish the necessary core cooling, energetic fuel-coolant interactions (FCI`s commonly called `vapor explosions`) could occur as a result of the core melting and coolant contact. Although a large number of studies have been done on energetic FCI`s, very few experiments have been performed with the actual fuel materials postulated to be produced in severe accidents. Because of the scarcity of well-characterized FCI data for uranium allows in noncommercial reactors (cermet and silicide fuels), we have conducted a series of experiments to provide a data base for the foregoing materials. An existing 1-D shock-tube facility was modified to handle depleted radioactive materials (U{sub 3}O{sub 8}-Al, and U{sub 3}Si{sub 2}-Al). Our objectives have been to determine the effects of the initial fuel composition and temperature and the driving pressure (triggering) on the explosion work output, dynamic pressures, transient temperatures, and the hydrogen production. Experimental results indicate limited energetics, mainly thermal interactions, for these fuel materials as compared to aluminum where more chemical reactions occur between the molten aluminum and water.

  15. Chemical synthesis of hydrocarbon-stapled peptides for protein interaction research and therapeutic targeting.

    Science.gov (United States)

    Bird, Gregory H; Crannell, W Christian; Walensky, Loren D

    2011-09-01

    The peptide α-helix represents one of nature's most featured protein shapes and is employed in a diversity of protein architectures, from the cytoskeletal infrastructure to the most intimate contact points between crucial signaling proteins. By installing an all-hydrocarbon crosslink into native sequences, the shape and biological activity of natural peptide α-helices can be recapitulated, yielding a chemical toolbox that can be used both to interrogate the protein interactome and to modulate interaction networks for potential therapeutic benefit. Here, current methodology for synthesizing stabilized α-helices (SAH) corresponding to key protein interaction domains is described. A stepwise approach is taken for the production of crosslinking non-natural amino acids, incorporation of the residues into peptide templates, and application of ruthenium-catalyzed ring-closing metathesis to generate hydrocarbon-stapled peptides. Through facile derivatization and functionalization steps, SAHs can be tailored for a broad range of applications in biochemical, structural, proteomic, cellular, and in vivo studies. Curr. Protoc. Chem. Biol. 3:99-117 © 2011 by John Wiley & Sons, Inc.

  16. Extraction of CYP chemical interactions from biomedical literature using natural language processing methods.

    Science.gov (United States)

    Jiao, Dazhi; Wild, David J

    2009-02-01

    This paper proposes a system that automatically extracts CYP protein and chemical interactions from journal article abstracts, using natural language processing (NLP) and text mining methods. In our system, we employ a maximum entropy based learning method, using results from syntactic, semantic, and lexical analysis of texts. We first present our system architecture and then discuss the data set for training our machine learning based models and the methods in building components in our system, such as part of speech (POS) tagging, Named Entity Recognition (NER), dependency parsing, and relation extraction. An evaluation of the system is conducted at the end, yielding very promising results: The POS, dependency parsing, and NER components in our system have achieved a very high level of accuracy as measured by precision, ranging from 85.9% to 98.5%, and the precision and the recall of the interaction extraction component are 76.0% and 82.6%, and for the overall system are 68.4% and 72.2%, respectively.

  17. Interactions between ingredients in IMX-101: Reactive Chemical Processes Control Insensitive Munitions Properties

    Energy Technology Data Exchange (ETDEWEB)

    Maharrey, Sean P.; Wiese-Smith, Deneille; Highley, Aaron M.; Behrens, Richard,; Kay, Jeffrey J

    2014-03-01

    Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS) measurements have been conducted on a new Insensitive Munitions (IM) formulation. IMX-101 is the first explosive to be fully IM qualified under new NATO STANAG guidelines for fielded munitions. The formulation uses dinitroanisole (DNAN) as a new melt cast material to replace TNT, and shows excellent IM performance when formulated with other energetic ingredients. The scope of this work is to explain this superior IM performance by investigating the reactive processes occurring in the material when subjected to a well-controlled thermal environment. The dominant reactive processes observed were a series of complex chemical interactions between the three main ingredients (DNAN, NQ, and NTO) that occurs well below the onset of the normal decomposition process of any of the individual ingredients. This process shifts the thermal response of the formulations to a much lower temperature, where the kinetically controlled reaction processes are much slower. This low temperature shift has the effect of allowing the reactions to consume the reactive solids (NQ, NTO) well before the reaction rates increase and reach thermal runaway, resulting in a relatively benign response to the external stimuli. The main findings on the interaction processes are presented.

  18. Chemical and molecular aspects on interactions of galanthamine and its derivatives with cholinesterases.

    Science.gov (United States)

    Gulcan, Hayrettin O; Orhan, Ilkay E; Sener, Bilge

    2015-01-01

    Dual action of galanthamine as potent cholinesterase inhibitor and nicotinic modulator has attracted a great attention to be used in the treatment of AD. Consequently, galanthamine, a natural alkaloid isolated from a Galanthus species (snowdrop, Amaryllidaceae), has become an attractive model compound for synthesis of its novel derivatives to discover new drug candidates. Numerous studies have been done to elucidate interactions between galanthamine and its different derivatives and the enzymes; acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using in vitro and in silico experimental models. The in vitro studies revealed that galanthamine inhibits AChE in strong, competitive, long-acting, and reversible manner as well as BChE, although its selectivity towards AChE is much higher than BChE. The in silico studies carried out by employing molecular docking experiments as well as molecular dynamics simulations pointed out to existence of strong interactions of galanthamine with the active gorge of AChE, mostly of Torpedo californica (the Pasific electric ray) origin. In this review, we evaluate the mainstays of cholinesterase inhibitory action of galanthamine and its various derivatives from the point of view of chemical and molecular aspects.

  19. CRITIC2: A program for real-space analysis of quantum chemical interactions in solids

    Science.gov (United States)

    Otero-de-la-Roza, A.; Johnson, Erin R.; Luaña, Víctor

    2014-03-01

    We present CRITIC2, a program for the analysis of quantum-mechanical atomic and molecular interactions in periodic solids. This code, a greatly improved version of the previous CRITIC program (Otero-de-la Roza et al., 2009), can: (i) find critical points of the electron density and related scalar fields such as the electron localization function (ELF), Laplacian, … (ii) integrate atomic properties in the framework of Bader’s Atoms-in-Molecules theory (QTAIM), (iii) visualize non-covalent interactions in crystals using the non-covalent interactions (NCI) index, (iv) generate relevant graphical representations including lines, planes, gradient paths, contour plots, atomic basins, … and (v) perform transformations between file formats describing scalar fields and crystal structures. CRITIC2 can interface with the output produced by a variety of electronic structure programs including WIEN2k, elk, PI, abinit, Quantum ESPRESSO, VASP, Gaussian, and, in general, any other code capable of writing the scalar field under study to a three-dimensional grid. CRITIC2 is parallelized, completely documented (including illustrative test cases) and publicly available under the GNU General Public License. Catalogue identifier: AECB_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECB_v2_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: yes No. of lines in distributed program, including test data, etc.: 11686949 No. of bytes in distributed program, including test data, etc.: 337020731 Distribution format: tar.gz Programming language: Fortran 77 and 90. Computer: Workstations. Operating system: Unix, GNU/Linux. Has the code been vectorized or parallelized?: Shared-memory parallelization can be used for most tasks. Classification: 7.3. Catalogue identifier of previous version: AECB_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 157 Nature of problem: Analysis of quantum-chemical

  20. How soil organic matter composition controls hexachlorobenzene-soil-interactions: adsorption isotherms and quantum chemical modeling.

    Science.gov (United States)

    Ahmed, Ashour A; Kühn, Oliver; Aziz, Saadullah G; Hilal, Rifaat H; Leinweber, Peter

    2014-04-01

    Hazardous persistent organic pollutants (POPs) interact in soil with the soil organic matter (SOM) but this interaction is insufficiently understood at the molecular level. We investigated the adsorption of hexachlorobenzene (HCB) on soil samples with systematically modified SOM. These samples included the original soil, the soil modified by adding a hot water extract (HWE) fraction (soil+3 HWE and soil+6 HWE), and the pyrolyzed soil. The SOM contents increased in the order pyrolyzed soilchemical composition between the soil samples suggested that alkylated aromatic, phenol, and lignin monomer compounds contributed most to the HCB adsorption. To obtain a molecular level understanding, a test set has been developed on the basis of elemental analysis which comprises 32 representative soil constituents. The calculated binding energy for HCB with each representative system shows that HCB binds to SOM stronger than to soil minerals. For SOM, HCB binds to alkylated aromatic, phenols, lignin monomers, and hydrophobic aliphatic compounds stronger than to polar aliphatic compounds confirming the above adsorption isotherms. Moreover, quantitative structure-activity relationship (QSAR) of the binding energy with independent physical properties of the test set systems for the first time indicated that the polarizability, the partial charge on the carbon atoms, and the molar volume are the most important properties controlling HCB-SOM interactions.

  1. Interactions of physical, chemical, and biological weather calling for an integrated approach to assessment, forecasting, and communication of air quality.

    Science.gov (United States)

    Klein, Thomas; Kukkonen, Jaakko; Dahl, Aslög; Bossioli, Elissavet; Baklanov, Alexander; Vik, Aasmund Fahre; Agnew, Paul; Karatzas, Kostas D; Sofiev, Mikhail

    2012-12-01

    This article reviews interactions and health impacts of physical, chemical, and biological weather. Interactions and synergistic effects between the three types of weather call for integrated assessment, forecasting, and communication of air quality. Today's air quality legislation falls short of addressing air quality degradation by biological weather, despite increasing evidence for the feasibility of both mitigation and adaptation policy options. In comparison with the existing capabilities for physical and chemical weather, the monitoring of biological weather is lacking stable operational agreements and resources. Furthermore, integrated effects of physical, chemical, and biological weather suggest a critical review of air quality management practices. Additional research is required to improve the coupled modeling of physical, chemical, and biological weather as well as the assessment and communication of integrated air quality. Findings from several recent COST Actions underline the importance of an increased dialog between scientists from the fields of meteorology, air quality, aerobiology, health, and policy makers.

  2. Signal and binding. II. Converting physico-chemical responses to macromolecule-ligand interactions into thermodynamic binding isotherms.

    Science.gov (United States)

    Bujalowski, Wlodzimierz; Jezewska, Maria J; Bujalowski, Paul J

    2017-03-01

    Physico-chemical titration techniques are the most commonly used methods in characterizing molecular interactions. These methods are mainly based on spectroscopic, calorimetric, hydrodynamic, etc., measurements. However, truly quantitative physico-chemical methods are absolutely based on the determination of the relationship between the measured signal and the total average degree of binding in order to obtain meaningful interaction parameters. The relationship between the observed physico-chemical signal of whatever nature and the degree of binding must be determined and not assumed, based on some ad hoc intuitive relationship/model, leading to determination of the true binding isotherm. The quantitative methods reviewed and discussed here allow an experimenter to rigorously determine the degree of binding and the free ligand concentration, i.e., they lead to the construction of the thermodynamic binding isotherm in a model-independent fashion from physico-chemical titration curves. Copyright © 2016. Published by Elsevier B.V.

  3. Chemical Assignment of Symmetry-Adapted Perturbation Theory Interaction Energy Components: The Functional-Group SAPT Partition.

    Science.gov (United States)

    Parrish, Robert M; Parker, Trent M; Sherrill, C David

    2014-10-14

    Recently, we introduced an effective atom-pairwise partition of the many-body symmetry-adapted perturbation theory (SAPT) interaction energy decomposition, producing a method known as atomic SAPT (A-SAPT) [Parrish, R. M.; Sherrill, C. D. J. Chem. Phys. 2014, 141, 044115]. A-SAPT provides ab initio atom-pair potentials for force field development and also automatic visualizations of the spatial contributions of noncovalent interactions, but often has difficulty producing chemically useful partitions of the electrostatic energy, due to the buildup of oscillating partial charges on adjacent functional groups. In this work, we substitute chemical functional groups in place of atoms as the relevant local quasiparticles in the partition, resulting in a functional-group-pairwise partition denoted as functional-group SAPT (F-SAPT). F-SAPT assigns integral sets of local occupied electronic orbitals and protons to chemical functional groups and linking σ bonds. Link-bond contributions can be further assigned to chemical functional groups to simplify the analysis. This approach yields a SAPT partition between pairs of functional groups with integral charge (usually neutral), preventing oscillations in the electrostatic partition. F-SAPT qualitatively matches chemical intuition and the cut-and-cap fragmentation technique but additionally yields the quantitative many-body SAPT interaction energy. The conceptual simplicity, chemical utility, and computational efficiency of F-SAPT is demonstrated in the context of phenol dimer, proflavine(+)-DNA intercalation, and a cucurbituril host-guest inclusion complex.

  4. Prioritization of Contaminants of Emerging Concern in Wastewater Treatment Plant Discharges Using Chemical:Gene Interactions in Caged Fish.

    Science.gov (United States)

    Perkins, Edward J; Habib, Tanwir; Escalon, Barbara L; Cavallin, Jenna E; Thomas, Linnea; Weberg, Matthew; Hughes, Megan N; Jensen, Kathleen M; Kahl, Michael D; Villeneuve, Daniel L; Ankley, Gerald T; Garcia-Reyero, Natàlia

    2017-08-01

    We examined whether contaminants present in surface waters could be prioritized for further assessment by linking the presence of specific chemicals to gene expression changes in exposed fish. Fathead minnows were deployed in cages for 2, 4, or 8 days at three locations near two different wastewater treatment plant discharge sites in the Saint Louis Bay, Duluth, MN and one upstream reference site. The biological impact of 51 chemicals detected in the surface water of 133 targeted chemicals was determined using biochemical endpoints, exposure activity ratios for biological and estrogenic responses, known chemical:gene interactions from biological pathways and knowledge bases, and analysis of the covariance of ovary gene expression with surface water chemistry. Thirty-two chemicals were significantly linked by covariance with expressed genes. No estrogenic impact on biochemical endpoints was observed in male or female minnows. However, bisphenol A (BPA) was identified by chemical:gene covariation as the most impactful estrogenic chemical across all exposure sites. This was consistent with identification of estrogenic effects on gene expression, high BPA exposure activity ratios across all test sites, and historical analysis of the study area. Gene expression analysis also indicated the presence of nontargeted chemicals including chemotherapeutics consistent with a local hospital waste stream. Overall impacts on gene expression appeared to be related to changes in treatment plant function during rain events. This approach appears useful in examining the impacts of complex mixtures on fish and offers a potential route in linking chemical exposure to adverse outcomes that may reduce population sustainability.

  5. Interaction chromatography for characterization and large-scale fractionation of chemically heterogeneous copolymers

    Science.gov (United States)

    Han, Junwon

    The remarkable development of polymer synthesis techniques to make complex polymers with controlled chain architectures has inevitably demanded the advancement of polymer characterization tools to analyze the molecular dispersity in polymeric materials beyond size exclusion chromatography (SEC). In particular, man-made synthetic copolymers that consist of more than one monomer type are disperse mixtures of polymer chains that have distributions in terms of both chemical heterogeneity and chain length (molar mass). While the molecular weight distribution has been quite reliably estimated by the SEC, it is still challenging to properly characterize the chemical composition distribution in the copolymers. Here, I have developed and applied adsorption-based interaction chromatography (IC) techniques as a promising tool to characterize and fractionate polystyrene-based block, random and branched copolymers in terms of their chemical heterogeneity. The first part of this thesis is focused on the adsorption-desorption based purification of PS-b-PMMA diblock copolymers using nanoporous silica. The liquid chromatography analysis and large scale purification are discussed for the PS-b-PMMA block copolymers that have been synthesized by sequential anionic polymerization. SEC and IC are compared to critically analyze the contents of PS homopolymers in the as-synthesized block copolymers. In addition, I have developed an IC technique to provide faster and more reliable information on the chemical heterogeneity in the as-synthesized block copolymers. Finally, a large scale (multi-gram) separation technique is developed to obtain "homopolymer-free" block copolymers via a simple chromatographic filtration technique. By taking advantage of the large specific surface area of nanoporous silica (≈300m 2/g), large scale purification of neat PS-b-PMMA has successfully been achieved by controlling adsorption and desorption of the block copolymers on the silica gel surface using a

  6. Interaction of environmental moisture with powdered green tea formulations: effect on catechin chemical stability.

    Science.gov (United States)

    Ortiz, J; Ferruzzi, M G; Taylor, L S; Mauer, L J

    2008-06-11

    Green tea and tea catechins must be stable in finished products to deliver health benefits; however, they may be adversely affected by tea processing/storage conditions and the presence of other components. The objective of this study was to determine the effects of storage relative humidity (RH) and addition of other ingredients on catechin stability in simulated dry beverage mixtures. Samples of green tea powder alone and mixed with sucrose, citric acid, and/or ascorbic acid were prepared and stored in desiccators at 22 degrees C and 0-85% RH for up to 3 months. Epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate were determined by high-performance liquid chromatography (HPLC). Formulation and the interaction of formulation and RH significantly promoted catechin degradation ( P or = 58% RH by the presence of powdered citric acid and at > or = 75% RH by the presence of ascorbic acid. Catechins degraded the most in formulations containing both acids. Although catechin chemical stability was maintained at < or = 43% RH in all samples stored at 22 degrees C for 3 months, caking was observed in samples at these relative humidities. These results are the first to demonstrate that addition of other dry components to tea powders may affect catechin stability in finished dry blends and highlight the importance of considering the complex interplay between a multicomponent system and its environment for developing stable products.

  7. Textural and chemical consequences of interaction between hydrous mafic and felsic magmas: an experimental study

    Science.gov (United States)

    Pistone, Mattia; Blundy, Jonathan D.; Brooker, Richard A.

    2016-01-01

    Mantle-derived, hydrous mafic magmas are often invoked as a mechanism to transfer heat, mass and volatiles to felsic plutons in the Earth's crust. Field observations suggest that mafic, water-rich magmas often intrude viscous felsic crystal-rich mushes. This scenario can advect water from the crystallising mafic magma to the felsic magma, leading to an increase in melt fraction in the felsic mush and subsequent mobilisation, at the same time as the mafic magma becomes quenched through a combination of cooling and water loss. To investigate such a scenario, we conducted experiments on a water-undersaturated (4 wt% H2O in the interstitial melt) dacitic crystal mush (50-80 vol% quartz crystals) subject to volatile supply from a water-saturated (≥6 wt% H2O) andesite magma at 950 °C and 4 kbar. Our experimental run products show unidirectional solidification textures (i.e. comb layering) as crystals nucleate at the mafic-felsic interface and grow into the mafic end-member. This process is driven by isothermal and isobaric undercooling resulting from a change in liquidus temperature as water migrates from the mafic to the felsic magma. We refer to this process as "chemical quenching" and suggest that some textures associated with natural mafic-felsic interactions are not simply cooling-driven in origin, but can be caused by exsolution of volatiles adjacent to an interface, whether a water-undersaturated felsic magma (as in our experiments) or a fracture.

  8. Changes in chemical interactions and protein conformation during heat-induced wheat gluten gel formation.

    Science.gov (United States)

    Wang, Kai-Qiang; Luo, Shui-Zhong; Zhong, Xi-Yang; Cai, Jing; Jiang, Shao-Tong; Zheng, Zhi

    2017-01-01

    In order to elucidate the heat-induced wheat gluten gel formation mechanism, changes in chemical interactions and protein conformation were investigated during gelation. The contribution of ionic and hydrogen bonds were found to decrease from 0.746 and 4.133g/L to 0.397 and 2.733g/L, respectively, as the temperature increased from 25 to 90°C. Moreover, the free SH content remarkably decreased from 37.91 to 19.79μmol/g during gelation. Ultraviolet absorption spectra and intrinsic fluorescence spectra suggested that wheat gluten unfolded during the heating process. In addition, wheat gluten gels treated at 80 and 90°C exhibited a "steric hindrance" effect, which can be attributed to the formation of aggregates. Fourier transform infrared spectra suggested that the random coil content increased at low temperatures (40 and 50°C), whereas the content of intermolecular β-sheets due to protein aggregation increased from 38.10% to 44.28% when the gelation temperature was 90°C.

  9. Stabilization of Protein-Protein Interactions in chemical biology and drug discovery.

    Science.gov (United States)

    Bier, David; Thiel, Philipp; Briels, Jeroen; Ottmann, Christian

    2015-10-01

    More than 300,000 Protein-Protein Interactions (PPIs) can be found in human cells. This number is significantly larger than the number of single proteins, which are the classical targets for pharmacological intervention. Hence, specific and potent modulation of PPIs by small, drug-like molecules would tremendously enlarge the "druggable genome" enabling novel ways of drug discovery for essentially every human disease. This strategy is especially promising in diseases with difficult targets like intrinsically disordered proteins or transcription factors, for example neurodegeneration or metabolic diseases. Whereas the potential of PPI modulation has been recognized in terms of the development of inhibitors that disrupt or prevent a binary protein complex, the opposite (or complementary) strategy to stabilize PPIs has not yet been realized in a systematic manner. This fact is rather surprising given the number of impressive natural product examples that confer their activity by stabilizing specific PPIs. In addition, in recent years more and more examples of synthetic molecules are being published that work as PPI stabilizers, despite the fact that in the majority they initially have not been designed as such. Here, we describe examples from both the natural products as well as the synthetic molecules advocating for a stronger consideration of the PPI stabilization approach in chemical biology and drug discovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Studies of chemical interactions between chlorosulphonated polyethylene and nit rile rubber

    Directory of Open Access Journals (Sweden)

    Marković Gordana

    2005-01-01

    Full Text Available Highly polar rubbers interact with each other through their active functional groups via condensation or substitution reactions at high temperature. Chlorosulphonated polyethylene (CSM rubber is a highly reactive rubber, the reactivity of with is due to the -SO2CI groups. When CSM reacts with nit rile rubber (NBR, a chemical reaction takes place between the two rubbers at high temperature. Fourier transform infrared (FTIR studies support that CSM/NBR (50/50 w/w isothermally induces a self cross-linking blend, when cross-linking takes place via the acrylonitrile groups of NBR and the SO2CI groups or the insitu generated allyl chloride moieties of CSM. There is a loss of some -CN groups during cross-linking. This may be due to an attack on the -CN groups by HCI (produced during the heating of CSM in the presence of inherent moisture in the polymers. Amid type of linkage is formed due to cross-linking.

  11. Physico-chemical interactions at the concrete-bitumen interface of nuclear waste repositories

    Directory of Open Access Journals (Sweden)

    Sablayrolles C.

    2013-07-01

    Full Text Available This study investigates the fate of nitrate and organic acids at the bitumenconcrete-steel interface within a repository storage cell for long-lived, intermediatelevel, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V-paste specimens were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. C-steel chips, simulating the presence of steel in the repository, were added in the systems for some experiments. The concentrations of anions (acetate, oxalate, nitrate, and nitrite and cations (calcium, potassium, ammonium and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the absence of steel, whereas, reduction of nitrates was observed in the presence of steel (production of NH4+. The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching; no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium.

  12. A Framework for Assessing Chemical/Nonchemical Interactions: A Case Study of Lead and Psychosocial Stress

    Science.gov (United States)

    Chemical and nonchemical stressors may contribute to negative health consequences in certain individuals. Nonchemical stressors include poverty, crowding, noise, and exposure to violence. Research has suggested that some nonchemical stressors may alter chemical toxicity. We propo...

  13. Demonstration of fuel resistant to pellet-cladding interaction. Phase 2. First semiannual report, January-June 1979. [BWR

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbaum, H.S. (comp.)

    1979-08-01

    This program has as its ultimate objective the demonstration of an advanced fuel design that is resistant to the failure mechanism known as fuel pellet-cladding interaction (PCI). Two fuel concepts are being developed for possible demonstration within this program: (a) Cu-barrier fuel and (b) Zr-liner fuel. These advanced fuels (known collectively as barrier fuels) have special fuel cladding designed to protect the Zircaloy cladding tube from the harmful effects of localized stress and reactive fission products during reactor service. This is the first semiannual progress report for Phase 2 of this program (January-June 1979). Progress in the irradiation testing of barrier fuel and of unfueled barrier cladding specimens is reported.

  14. Non-chemical stressors and cumulative risk assessment: an overview of current initiatives and potential air pollutant interactions.

    Science.gov (United States)

    Lewis, Ari S; Sax, Sonja N; Wason, Susan C; Campleman, Sharan L

    2011-06-01

    Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit

  15. Chemical Interaction Analysis of an Adhesive Containing 10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP) With the Dentin in Noncarious Cervical Lesions.

    Science.gov (United States)

    Oliveira, Bmb; Ulbaldini, Alm; Sato, F; Baesso, M L; Bento, A C; Andrade, Lhc; Lima, S M; Pascotto, R C

    2017-02-03

    The purpose of this study was to evaluate the chemical bonds of a self-etch 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) adhesive to natural noncarious cervical lesions (NCCLs) and compare them with those occurring in sclerotic dentin in artificially prepared defects (APDs). Four human teeth with natural NCCLs on the buccal surface were selected. Artificial defects matching the natural lesions were prepared on the lingual surface of the same teeth serving as control. Micro-Raman (MR) spectroscopy was used to quantify mineral content in natural NCCLs and in APDs. Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) readouts were taken before and after adhesive application to analyze the protein matrix/mineral (M:M) ratio and chemical interactions between 10-MDP adhesive and dentin. The MR and FTIR-PAS spectra collected from natural NCCLs demonstrated a larger area of the band (961 cm(-1), PO4) and lower M:M ratio, respectively, characterizing a hypermineralized dentin, compared with APDs. FTIR-PAS demonstrated emergence of a peak (1179 cm(-1), P=O) in spectra after adhesive treatment, demonstrating a more intense chemical interaction in natural NCCLs. The results demonstrated that chemical bonding of 10-MDP adhesive to natural NCCLs is more intense, due to the hypermineralized surface, and suggest that it is unnecessary to remove the hypermineralized layer with burs, as this may decrease the chemical bonding potential of 10-MDP.

  16. Role of charge transfer interaction and the chemical physics behind effective fulleropyrrolidine/porphyrin non-covalent interaction in solution.

    Science.gov (United States)

    Mondal, Ashis; Santhosh, Kotni; Bauri, Ajoy; Bhattacharya, Sumanta

    2014-01-01

    The present paper reports the photophysical insights on supramolecular interaction of a monoporphyrin derivative, namely, 1, with C60 pyrrolidine tris-acid ethyl ester (PyC60) in toluene and benzonitrile. The ground state interaction between PyC60 and 1 is facilitated through charge transfer interaction. Both UV-Vis and steady state measurements elicit almost similar magnitude of binding constant for the PyC60/1 complex in toluene and benzonitrile, viz., 6825 and 6540 dm(3 )mol(-1), respectively. Life time measurement evokes that rate of charge separation is fast in benzonitrile. Both hybrid-DFT and DFT calculations provide very good support in favor of electronic charge-separation in PyC60/1 system in vacuo.

  17. Finite-size, chemical-potential and magnetic effects on the phase transition in a four-fermion interacting model

    Energy Technology Data Exchange (ETDEWEB)

    Correa, E.B.S. [Universidade Federal do Sul e Sudeste do Para, Instituto de Ciencias Exatas, Maraba (Brazil); Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Linhares, C.A. [Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro (Brazil); Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Malbouisson, J.M.C. [Universidade Federal da Bahia, Instituto de Fisica, Salvador (Brazil); Santana, A.E. [Universidade de Brasilia, Instituto de Fisica, Brasilia, DF (Brazil)

    2017-04-15

    We study effects coming from finite size, chemical potential and from a magnetic background on a massive version of a four-fermion interacting model. This is performed in four dimensions as an application of recent developments for dealing with field theories defined on toroidal spaces. We study effects of the magnetic field and chemical potential on the size-dependent phase structure of the model, in particular, how the applied magnetic field affects the size-dependent critical temperature. A connection with some aspects of the hadronic phase transition is established. (orig.)

  18. Effective identification of Akt interacting proteins by two-step chemical crosslinking, co-immunoprecipitation and mass spectrometry.

    Science.gov (United States)

    Huang, Bill X; Kim, Hee-Yong

    2013-01-01

    Akt is a critical protein for cell survival and known to interact with various proteins. However, Akt binding partners that modulate or regulate Akt activation have not been fully elucidated. Identification of Akt-interacting proteins has been customarily achieved by co-immunoprecipitation combined with western blot and/or MS analysis. An intrinsic problem of the method is loss of interacting proteins during procedures to remove non-specific proteins. Moreover, antibody contamination often interferes with the detection of less abundant proteins. Here, we developed a novel two-step chemical crosslinking strategy to overcome these problems which resulted in a dramatic improvement in identifying Akt interacting partners. Akt antibody was first immobilized on protein A/G beads using disuccinimidyl suberate and allowed to bind to cellular Akt along with its interacting proteins. Subsequently, dithiobis[succinimidylpropionate], a cleavable crosslinker, was introduced to produce stable complexes between Akt and binding partners prior to the SDS-PAGE and nanoLC-MS/MS analysis. This approach enabled identification of ten Akt partners from cell lysates containing as low as 1.5 mg proteins, including two new potential Akt interacting partners. None of these but one protein was detectable without crosslinking procedures. The present method provides a sensitive and effective tool to probe Akt-interacting proteins. This strategy should also prove useful for other protein interactions, particularly those involving less abundant or weakly associating partners.

  19. INTERACTION-MEDIATED GROWTH OF CARBON NANOTUBES ON ACICULAR SILICA-COATED α-Fe CATALYST BY CHEMICAL VAPOR DEPOSITION

    Institute of Scientific and Technical Information of China (English)

    Qixiang Wang; Guoqing Ning; Fei Wei; Guohua Luo

    2003-01-01

    Multi-walled carbon nanotubes (MWNTs) with 20 nm outer diameter were prepared by chemical vapor deposition of ethylene using ultrafine surface-modified acicular α-Fe catalyst particles. The growth mechanism of MWNTs on the larger catalyst particles are attributed to the interaction between the Fe nanoparticles with the surface-modified silica layer. This interaction-mediated growth mechanism is illustrated by studying the electronic, atomic and crystal properties of surface-modified catalysts and MWNTs products by characterization with X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA) and Raman spectra.

  20. Magnesium bicarbonate and carbonate interactions in aqueous solutions: An infrared spectroscopic and quantum chemical study

    Science.gov (United States)

    Stefánsson, Andri; Lemke, Kono H.; Bénézeth, Pascale; Schott, Jacques

    2017-02-01

    The interaction of magnesium with bicarbonate and carbonate ions in aqueous solutions was studied using infrared spectroscopy and quantum chemical calculations. Using the infrared vibrational bands for HCO3- and CO32- at 1200-1450 cm-1 (δC-OH, vS and v3) together with their molar absorptivity (ε), the concentrations of the HCO3- and CO32- ions and the corresponding Mg ion pairs have been determined. In the absence of Mg2+, measured spectra were accurately reproduced assuming that only HCO3- and CO32- were present in solution. Upon addition of Mg2+ at fixed pH, infrared spectra were observed to shift indicating presence of the MgHCO3+ and MgCO3 (aq) ion pairs. From measurements, the second ionization constant of carbonic acid and the MgHCO3+ and MgCO3 (aq) ion pair formation constants have been obtained, these being logK2 = -10.34 ± 0.04, logKMgHCO3+ = 1.12 ± 0.11 and logKMgCO3 = 2.98 ± 0.06, respectively. To support our experimental infrared measurements and to gain further insight into the molecular nature of the ion pair formation, density functional theory (DFT) calculations with VPT2 anharmonic correction were conducted. The most stable geometries predicted for the MgHCO3+ and MgCO3 (aq) ion pairs were a bi-dentate [MgHCO3]+(H2O)n and a monodentate [MgHCO3]+(OH)(H2O)n complexes, respectively. The predicted frequencies for HCO3-, CO32- and MgHCO3+ were found to shift toward those experimentally measured with an increasing H2O solvation number where possible band shifts were predicted for MgCO3 (aq) relative to CO32-, this being dependent on the exact structure and hydration of the bulk MgCO3 (aq) ion pair. Experimentally, the ion pair formations were found to have insignificant effects on the δC-OH, vS and v3 vibrational frequencies. The speciation of dissolved inorganic carbon may be significantly influenced by ion pair formation, particularly in alkaline solutions where they may be the predominant species.

  1. Chemical thermodynamics of fusion reactor breeding materials and their interaction with tritium

    Energy Technology Data Exchange (ETDEWEB)

    Ihle, H.R.; Wu, C.H. (Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.))

    1985-02-01

    Liquid lithium, lithium alloys (solid and liquid) and ceramic lithium compounds are candidate breeding materials for (D, T) fusion reactors. Besides their tritium breeding capability, which results from neutron capture, their thermochemical properties and their interaction with tritium are of particular interest. A good knowledge of the physical and chemical properties of liquid lithium exists; and the systems Li-LiH, Li-LiD and Li-LiT have been studied in great detail. For dilute solutions of D/sub 2/ in liquid lithium, Sieverts' law was found to be valid down to an atom fraction of xsub(D)=10/sup -6/; in the vapor, lithium polymers up to Li/sub 4/ and lithium deuterides are found. In the system liquid Li-Pb, the solubility of D/sub 2/ was measured as a function of temperature and alloy composition, and correlated with the activities of the constituent metals. The solubility of D/sub 2/ was found to obey Sieverts' law at low concentrations, and is many orders of magnitude smaller than that in liquid lithium. This holds also for solid 'Li/sub 7/ Pb/sub 2/'. Vaporization studies yielded data on the thermal stability of the oxides: Li/sub 2/O, ..gamma..-LiAlO/sub 2/, ..beta..-Li/sub 5/AlO/sub 4/, LiAl/sub 5/O/sub 8/, Li/sub 2/ZrO/sub 3/, Li/sub 4/ZrO/sub 4/, Li/sub 8/ZrO/sub 6/, Li/sub 2/SiO/sub 3/ and Li/sub 4/SiO/sub 4/. Tritium diffusivity was studied in Li/sub 2/O, ..gamma..-LiAlO/sub 2/, ..beta..-Li/sub 5/AlO/sub 4/ and Li/sub 4/SiO/sub 4/. A large number of gaseous lithides were detected during these studies.

  2. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    OpenAIRE

    Liu Yang; Qiang Han; Shuya Cao; Feng Huang; Molin Qin; Chenghai Guo; Mingyu Ding

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical an...

  3. Combination of cascade chemical reactions with graphene-DNA interaction to develop new strategy for biosensor fabrication.

    Science.gov (United States)

    Zhu, Xiaoli; Sun, Liya; Chen, Yangyang; Ye, Zonghuang; Shen, Zhongming; Li, Genxi

    2013-09-15

    Graphene, a single atom thick and two dimensional carbon nano-material, has been proven to possess many unique properties, one of which is the recent discovery that it can interact with single-stranded DNA through noncovalent π-π stacking. In this work, we demonstrate that a new strategy to fabricate many kinds of biosensors can be developed by combining this property with cascade chemical reactions. Taking the fabrication of glucose sensor as an example, while the detection target, glucose, may regulate the graphene-DNA interaction through three cascade chemical reactions, electrochemical techniques are employed to detect the target-regulated graphene-DNA interaction. Experimental results show that in a range from 5μM to 20mM, the glucose concentration is in a natural logarithm with the logarithm of the amperometric response, suggesting a best detection limit and detection range. The proposed biosensor also shows favorable selectivity, and it has the advantage of no need for labeling. What is more, by controlling the cascade chemical reactions, detection of a variety of other targets may be achieved, thus the strategy proposed in this work may have a wide application potential in the future.

  4. Supramolecular Interactions in Secondary Plant Cell Walls: Effect of Lignin Chemical Composition Revealed with the Molecular Theory of Solvation.

    Science.gov (United States)

    Silveira, Rodrigo L; Stoyanov, Stanislav R; Gusarov, Sergey; Skaf, Munir S; Kovalenko, Andriy

    2015-01-02

    Plant biomass recalcitrance, a major obstacle to achieving sustainable production of second generation biofuels, arises mainly from the amorphous cell-wall matrix containing lignin and hemicellulose assembled into a complex supramolecular network that coats the cellulose fibrils. We employed the statistical-mechanical, 3D reference interaction site model with the Kovalenko-Hirata closure approximation (or 3D-RISM-KH molecular theory of solvation) to reveal the supramolecular interactions in this network and provide molecular-level insight into the effective lignin-lignin and lignin-hemicellulose thermodynamic interactions. We found that such interactions are hydrophobic and entropy-driven, and arise from the expelling of water from the mutual interaction surfaces. The molecular origin of these interactions is carbohydrate-π and π-π stacking forces, whose strengths are dependent on the lignin chemical composition. Methoxy substituents in the phenyl groups of lignin promote substantial entropic stabilization of the ligno-hemicellulosic matrix. Our results provide a detailed molecular view of the fundamental interactions within the secondary plant cell walls that lead to recalcitrance.

  5. Physical and Chemical Interactions with Conspecifics Mediate Sex Change in a Protandrous Gastropod Crepidula fornicata.

    Science.gov (United States)

    Cahill, Abigail E; Juman, Alia Rehana; Pellman-Isaacs, Aaron; Bruno, William T

    2015-12-01

    The protandrous marine snail Crepidula fornicata has been a theoretical and empirical model for studies of sex change for many decades. We investigated the social conditions under which sex change occurs in this species by manipulating physical and chemical contact with conspecifics. Male snails were either in physical and chemical contact with females or in chemical contact with, but physically isolated from, females. Males were tested both with living females and with empty, sterilized shells. Males that were physically touching a living female were less likely to change sex than the isolated controls, while males in chemical (but not physical) contact with females changed sex no slower than the isolated controls. These results provide experimental evidence that the factor controlling sex change in C. fornicata is due to a contact-borne inhibitor associated with female conspecifics. These findings serve as a basis for future studies of sex change in this model system.

  6. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, D. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Mercader, C.; Quere, S.; Hairault, L. [CEA, DAM, Le Ripault, F-37260 Monts (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Methivier, C. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Pradier, C.M., E-mail: claire-Marie.pradier@upmc.fr [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Measurements of interactions by Quartz Crystal Microbalance. Black-Right-Pointing-Pointer AFM and CFM measurements, tip functionalisation. Black-Right-Pointing-Pointer Surface nano-imaging. - Abstract: By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  7. The response of the polarized Fermi mixture to an artificial vector potential: The interaction strength and imbalance chemical potential effects

    Science.gov (United States)

    Ebrahimian, N.; Safiee, Z.

    2017-03-01

    We consider a polarized Fermi mixture (with normal-superfluid phase separation), subjected to artificial vector potential. We concentrate on the BCS regime with various interaction strengths and numerically obtain the polarisability of the system. We obtain the functional dependence of the polarisability of the system on frequency and the relevant physical parameters, namely the interaction strength, the mass ratio, the average and imbalance chemical potentials. Also, we find the special frequency (ωs), for which the rate of the response of system to the potential is changed and the cut-off frequency (ωcutoff), for which the response starts to become infinity. We investigate the behavior of the curves of polarisability versus proper physical parameters for ω physical parameters. Finally, the system's response can be controlled by relevant physical parameters, such as interaction strength.

  8. Chemical projectile-target interaction during hypervelocity cratering experiments (MEMIN project).

    Science.gov (United States)

    Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The detection and identification of meteoritic components in impact-derived rocks are of great value for confirming an impact origin and reconstructing the type of extraterrestrial material that repeatedly stroke the Earth during geologic evolution [1]. However, little is known about processes that control the projectile distribution into the various impactites that originate during the cratering and excavation process, and inter-element fractionation between siderophile elements during impact cratering. In the context of the MEMIN project, cratering experiments have been performed using spheres of Cr-V-Co-Mo-W-rich steel and of the iron meteorite Campo del Cielo (IAB) as projectiles accelerated to about 5 km/s, and blocks of Seeberger sandstone as target. The experiments were carried out at the two-stage acceleration facilities of the Fraunhofer Ernst-Mach-Institute (Freiburg). Our results are based on geochemical analyses of highly shocked ejecta material. The ejecta show various shock features including multiple sets of planar deformations features (PDF) in quartz, diaplectic quartz, and partial melting of the sandstone. Melting is concentrated in the phyllosilicate-bearing sandstone matrix but involves quartz, too. Droplets of molten projectile have entered the low-viscosity sandstone melt but not quartz glass. Silica-rich sandstone melts are enriched in the elements that are used to trace the projectile, like Fe, Ni, Cr, Co, and V (but no or little W and Mo). Inter-element ratios of these "projectile" tracer elements within the contaminated sandstone melt may be strongly modified from the original ratios in the projectiles. This fractionation most likely result from variation in the lithophile or siderophile character and/or from differences in reactivity of these tracer elements with oxygen [2] during interaction of metal melt with silicate melt. The shocked quartz with PDF is also enriched in Fe and Ni (experiment with a meteorite iron projectile) and in Fe

  9. Thermal-chemical-mechanical feedback during fluid-rock interactions: Implications for chemical transport and scales of equilibria in the crust

    Energy Technology Data Exchange (ETDEWEB)

    Dutrow, Barbara

    2008-08-13

    Our research evaluates the hypothesis that feedback amongst thermal-chemical-mechanical processes operative in fluid-rock systems alters the fluid flow dynamics of the system which, in turn, affects chemical transport and temporal and spatial scales of equilibria, thus impacting the resultant mineral textural development of rocks. Our methods include computational experimentation and detailed analyses of fluid-infiltrated rocks from well-characterized terranes. This work focuses on metamorphic rocks and hydrothermal systems where minerals and their textures are utilized to evaluate pressure (P), temperature (T), and time (t) paths in the evolution of mountain belts and ore deposits, and to interpret tectonic events and the timing of these events. Our work on coupled processes also extends to other areas where subsurface flow and transport in porous media have consequences such as oil and gas movement, geothermal system development, transport of contaminants, nuclear waste disposal, and other systems rich in fluid-rock reactions. Fluid-rock systems are widespread in the geologic record. Correctly deciphering the products resulting from such systems is important to interpreting a number of geologic phenomena. These systems are characterized by complex interactions involving time-dependent, non-linear processes in heterogeneous materials. While many of these interactions have been studied in isolation, they are more appropriately analyzed in the context of a system with feedback. When one process impacts another process, time and space scales as well as the overall outcome of the interaction can be dramatically altered. Our goals to test this hypothesis are: to develop and incorporate algorithms into our 3D heat and mass transport code to allow the effects of feedback to be investigated numerically, to analyze fluid infiltrated rocks from a variety of terranes at differing P-T conditions, to identify subtle features of the infiltration of fluids and/or feedback, and

  10. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    produced ash has significant and not always constructive pedological, ecological, hydrological and geomorphological effects and impacts (Shakesby, 2011). Abundant scientific information is assembled either from control fires by collecting samples before and after wildfire event, or conducting laboratory experiments exanimating data under truly isolated conditions (Lugassi et al., 2013). However, an integration and synthesis of the knowledge about ash including deeper understanding of inter-correlation between chemical, physical and morphological compounds in open post-burn environment and its possible interactions in soil formation or impact on soil composition are highly needed. The main aim of the presented study was to advance the science of soil-fire relationship by recognizing the remains ash as a new soil-forming factor, on par with the traditionally recognized factors: parent material, topography, time, climate, organisms, and recently recognized human activity as the sixth factor. This research was conducted to develop new methods to assess impacts and quantify the contributions/influences of post-fire products, mainly ash, on soil composition and soil properties in post-burned environment. We conducted several controlled experiments using 40 soil samples (typical Mediterranean Rendzina soil, pH 6.84, a grayish-brown, humus- and free calcium carbonate- rich, intra-zonal). The samples include bare soils and different types and loads of forest litter, were exposed to different temperatures (200° C, 400° C and 600° C) in a muffle furnace for 2 hours (Pereira et al. 2011) as fire temperature plays a key role in determining ash properties. The ash produced at a low temperatures (50% carbon and retains many of the structural characteristics of the parent material. At higher temperatures, the residue ash is greyish, consisted of very fine particles that preserve almost none of the original structural characteristics of the fuel (Woods and Balfour, 2008) creating

  11. Development of new materials and structures based on managed physical-chemical factors of local interaction

    Science.gov (United States)

    Urakov, A. L.

    2016-04-01

    The paper states that assigning certain physical and chemical characteristics to pills and medical drugs solutions can substitute for the development of new drugs (which is essentially equivalent to the creation of new medicines). It is established that the purposeful change of physical and chemical characteristics of the standard ("old") materials (in other words, the known substances) is fundamental for the production of solid and liquid medicines, which allows us to get "new" structures and materials. The paper shows that assigning new physical and chemical properties to "old" materials and their further usage for the production of tablets and solutions from the "old" and well-known medicines can turn even very "old" medicine into very "novel" (moreover, even very fashionable) one with unprecedented (fantastic) pharmacological activity and new mechanisms of action.

  12. Nanostructure-directed chemical sensing: The IHSAB principle and the dynamics of acid/base-interface interaction

    Directory of Open Access Journals (Sweden)

    James L. Gole

    2013-01-01

    Full Text Available Nanostructure-decorated n-type semiconductor interfaces are studied in order to develop chemical sensing with nanostructured materials. We couple the tenets of acid/base chemistry with the majority charge carriers of an extrinsic semiconductor. Nanostructured islands are deposited in a process that does not require self-assembly in order to direct a dominant electron-transduction process that forms the basis for reversible chemical sensing in the absence of chemical-bond formation. Gaseous analyte interactions on a metal-oxide-decorated n-type porous silicon interface show a dynamic electron transduction to and from the interface depending upon the relative strength of the gas and metal oxides. The dynamic interaction of NO with TiO2, SnO2, NiO, CuxO, and AuxO (x >> 1, in order of decreasing acidity, demonstrates this effect. Interactions with the metal-oxide-decorated interface can be modified by the in situ nitridation of the oxide nanoparticles, enhancing the basicity of the decorated interface. This process changes the interaction of the interface with the analyte. The observed change to the more basic oxinitrides does not represent a simple increase in surface basicity but appears to involve a change in molecular electronic structure, which is well explained by using the recently developed IHSAB model. The optical pumping of a TiO2 and TiO2−xNx decorated interface demonstrates a significant enhancement in the ability to sense NH3 and NO2. Comparisons to traditional metal-oxide sensors are also discussed.

  13. Nanostructure-directed chemical sensing: The IHSAB principle and the dynamics of acid/base-interface interaction.

    Science.gov (United States)

    Gole, James L; Laminack, William

    2013-01-01

    Nanostructure-decorated n-type semiconductor interfaces are studied in order to develop chemical sensing with nanostructured materials. We couple the tenets of acid/base chemistry with the majority charge carriers of an extrinsic semiconductor. Nanostructured islands are deposited in a process that does not require self-assembly in order to direct a dominant electron-transduction process that forms the basis for reversible chemical sensing in the absence of chemical-bond formation. Gaseous analyte interactions on a metal-oxide-decorated n-type porous silicon interface show a dynamic electron transduction to and from the interface depending upon the relative strength of the gas and metal oxides. The dynamic interaction of NO with TiO(2), SnO(2), NiO, Cu(x)O, and Au(x)O (x > 1), in order of decreasing acidity, demonstrates this effect. Interactions with the metal-oxide-decorated interface can be modified by the in situ nitridation of the oxide nanoparticles, enhancing the basicity of the decorated interface. This process changes the interaction of the interface with the analyte. The observed change to the more basic oxinitrides does not represent a simple increase in surface basicity but appears to involve a change in molecular electronic structure, which is well explained by using the recently developed IHSAB model. The optical pumping of a TiO(2) and TiO(2-) (x)N(x) decorated interface demonstrates a significant enhancement in the ability to sense NH(3) and NO(2). Comparisons to traditional metal-oxide sensors are also discussed.

  14. Numerical simulation of the interaction of transport, diffusion and chemical reactions in an urban plume

    Science.gov (United States)

    Vogel, Bernhard; Vogel, Heike; Fiedler, Franz

    1994-01-01

    A model system is presented that takes into account the main physical and chemical processes on the regional scale here in an area of 100x100 sq km. The horizontal gridsize used is 2x2 sq km. For a case study, it is demonstrated how the model system can be used to separate the contributions of the processes advection, turbulent diffusion, and chemical reactions to the diurnal cycle of ozone. In this way, typical features which are visible in observations and are reproduced by the numerical simulations can be interpreted.

  15. Evidence for chemical bond formation at rubber-brass interface: Photoelectron spectroscopy study of bonding interaction between copper sulfide and model molecules of natural rubber

    Science.gov (United States)

    Ozawa, Kenichi; Mase, Kazuhiko

    2016-12-01

    Strong adhesion between rubber and brass has been considered to arise mainly from the mechanical interaction, which is characterized by dendritic interlocking at the interface. In order to examine a possible contribution of the chemical interaction, chemical state analysis was carried out for model molecules of natural rubber (2-methyl-2-butene and isoprene) adsorbed on Cu2S, a key chemical species for adhesion, by means of photoelectron spectroscopy (PES). Absence of a C 1s PES component associated with C=C bonds and the appearance of adsorption-induced components in the S 2p region indicate that the molecules interact with the Cu2S surface via the C=C bond to form C-S covalent bonds. This proves that the chemical interaction certainly plays a role in rubber-brass adhesion along with the mechanical interaction.

  16. Fe/C interactions during SWNT growth with C2 feedstock molecules: A quantum chemical molecular dynamics study.

    Science.gov (United States)

    Zheng, Guishan; Irle, Stephan; Morokuma, Keiji

    2006-05-01

    We are presenting the first quantum chemical molecular dynamics (QM/MD) model simulations for iron catalyzed single-walled carbon nanotube (SWNT) growth based on the density functional tight binding (DFTB) quantum chemical potential. As model systems, open-ended (10,10) armchair tube fragments were selected with 0, 10, and 20 Fe atoms attached in 1,4-positions on the open rims, and ensembles of randomly oriented C2 molecules were included to simulate carbon plasma feedstock molecules. Isokinetic trajectories at 1500 K to 3000 K show that divalent Fe increases the number of coordination partners with carbon and/or Fe, depending on the Fe concentration. Fe/C interactions weaken the tube sidewall due to electron transfer from Fe into antibonding carbon orbitals, and C2 addition occurs mainly in an Fe-C2-Fe bridge addition mechanism, while growth of polyyne chains characteristic for high-temperature carbon systems is suppressed in the presence of Fe on the rims of the growing SWNT. Our findings are the first quantum chemical evidence for the importance of intermetallic interactions during SWNT growth.

  17. Optical evidence for chemical interaction of the polyaniline/fullerene composites with N-methyl-2-pyrrolidinone

    Science.gov (United States)

    Baibarac, M.; Baltog, I.; Daescu, M.; Lefrant, S.; Chirita, P.

    2016-12-01

    Surface enhanced Raman scattering (SERS) spectroscopic studies reveal a particular chemical interaction of the polyaniline/fullerene (PANI/C60) composite with N-methyl-2-pyrrolidinone (NMP). The chemical polymerization of aniline in the presence of sulfuric acid, potassium dichromate and fullerene has been used for the preparation of the PANI/C60 composite. The polymerization reaction involves a doping of PANI with C60 anion radicals. The interaction of the composite with NMP leads to a de-doping of PANI that involves a transformation of leucoemeraldine salt (LS) repeating units into leucoemeraldine base (LB). Additionally, a gradual increasing in the intensity of the Raman line at 1452 cm-1 associated to the Ag(2) pentagonal pinch mode of fullerene and a decrease in the intensity of the Raman lines of PANI are reported. This change arises from the formation of a charge-transfer complex C60-NMP. The subsequent chemical treatment of PANI-LB with FeCl3 leads to the formation PANI-emeraldine salt. An inhibition of the transformation of PANI doped with C60 anion radicals into a PANI-LB and the C60-NMP charge transfer complex in the presence of CdS particles dispersed in NMP is demonstrated by SERS spectroscopy.

  18. Chemically-mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, Valerie J.; Kuffner, Ilsa B.; Walters, Linda J.; Ritson-Williams, Raphael; Beach, Kevin S.; Becerro, Mikel A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment.

  19. Chemically mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, V.J.; Kuffner, I.B.; Walters, L.J.; Ritson-Williams, R.; Beach, K.S.; Becerro, M.A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment. ?? 2011 Inter-Research.

  20. Chemical and microbiological interactions between soils and roots in commercial banana plantations (Musa AAA, cv. Cavendish)

    NARCIS (Netherlands)

    Segura Mena, R.; Serrano, E.; Pocasangre, L.; Acuna, O.; Bertsch, F.; Stoorvogel, J.J.; Sandoval, J.A.

    2015-01-01

    A study was performed to determine the relationships between soil chemical and microbiological con-ditions and how they impact soil production. The study was carried out on six Costa Rican commercialbanana farms with high, medium and low productivity. In each of the farms sector with relatively good

  1. Chemical Potential Dependence of the Dressed—Quark Propagator from an Effective Quark—Quark Interaction

    Institute of Scientific and Technical Information of China (English)

    ZONGHong-Shi; PINGJia-Lun; 等

    2002-01-01

    We exhibit a method for obtaining the low chemical potential dependence of the dressed quark propagator from the dressed-quark propagator,which provides a means of determining the behavior of the chiral and deconfinement order parameters.A comparison with the results of previous researches is given.

  2. Phase transition of strongly interacting matter with a chemical potential dependent Polyakov loop potential

    CERN Document Server

    Shao, Guo-yun; Di Toro, Massimo; Colonna, Maria; Gao, Xue-yan; Gao, Ning

    2016-01-01

    We construct a hadron-quark two-phase model based on the Walecka-quantum hadrodynamics and the improved Polyakov-Nambu--Jona-Lasinio model with an explicit chemical potential dependence of Polyakov-loop potential ($\\mu$PNJL model). With respect to the original PNJL model, the confined-deconfined phase transition is largely affected at low temperature and large chemical potential. Using the two-phase model, we investigate the equilibrium transition between hadronic and quark matter at finite chemical potentials and temperatures. The numerical results show that the transition boundaries from nuclear to quark matter move towards smaller chemical potential (lower density) when the $\\mu$-dependent Polyakov loop potential is taken. In particular, for charge asymmetric matter, we compute the local asymmetry of $u, d$ quarks in the hadron-quark coexisting phase, and analyse the isospin-relevant observables possibly measurable in heavy-ion collision (HIC) experiments. In general new HIC data on the location and proper...

  3. Innovations in bonding to zirconia-based materials. Part II: focusing on chemical interactions

    NARCIS (Netherlands)

    M.N. Aboushelib; H. Mirmohamadi; J.P. Matinlinna; E. Kukk; H.F. Ounsi; Z. Salameh

    2009-01-01

    Objectives: The zirconia-resin bond strength was enhanced using novel engineered zirconia primers in combination with selective infiltration etching as a surface pre-treatment. The aim of this study was to evaluate the effect of artificial aging on the chemical stability of the established bond and

  4. Chemical and biological interactions in the Rose Garden hydrothermal vent field, Galapagos spreading center

    Science.gov (United States)

    Johnson, Kenneth S.; Childress, James J.; Hessler, Robert R.; Sakamoto-Arnold, Carole M.; Beehler, Carl L.

    1988-10-01

    The concentrations of a suite of redox reactive chemicals were measured in the Rose Garden hydrothermal vent field of the Galapagos spreading center. Sulfide, silicate, oxygen and temperature distributions were measured in situ with a submersible chemical analyser. In addition, 15 chemical species were measured in discrete samples. Variability in the slope of the temperature-silicate plots indicates that heat is lost from these relatively low temperatures (<15°C) solutions by conduction to the solid phase. Consumption of oxygen, sulfide and nitrate from the hydrothermal solution as it flows past the vent animals is apparent from the distributions measured in situ and in the discrete samples. The fraction of sulfide and nitrate removed from the solution by consumption appears to have increased between 1979-1985. Sulfide and oxygen appear to be consumed under different conditions: sulfide is removed primarily from the warmest solutions, and oxygen is consumed only from the cold seawater. This separation may be driven primarily by the increased gradients of each chemical under these conditions. There is no evidence for the consumption of significant amounts of manganese(II) by the vent organisms. The analysis of other data sets from this vent field indicate no significant consumption of methane by the vent organisms, as well.

  5. An Internet-Based Distributed Laboratory for Interactive Chemical Engineering Education

    Science.gov (United States)

    Guo, Jing; Kettler, David J.; Al-Dahhan, Muthanna

    2007-01-01

    A common undergraduate chemical engineering experiment has been modified for on-line operation over the Internet. By adopting rapidly changing Internet and object component technologies, we developed a novel approach combining the Internet and regular laboratory equipment. The client-server applications use a Visual Basic and Labtech programming…

  6. METHODOLOGY FOR EXAMINING SYSTEM AGING DUE TO INTERACTIONS BETWEEN CHEMICALLY INCOMPATIBLE MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    J. DENINGER; J. TANSKI

    1999-04-01

    We start with a stored and unused population of fielded engineered units that are composed of chemically incompatible materials. The units age primarily through heterogeneous chemical reactions between the materials resulting in possible degradation in performance. The engineered units are unused in storage, but may be called into actual service at any time. We sample several units from the population per year and perform a number of non-destructive evaluation (NDE) techniques, such as radiography, low-frequency vibration analysis, and ultrasonic imaging on the selected units. From those units, some are selected for destructive testing (D-test) involving disassembly and testing of internal parts and components. Chemical analyses, mechanical properties measurements and other tests are performed. All of the above steps provide information that is used in the system simulation mathematical model. The system simulation model incorporates chemical reactions and gas-solid transport processes, along with changes in both the surface and bulk properties of the solids. Model results are used to suggest improvements in NDE analyses of the units and improvements in component and material analyses. Model results give trending indications of individual component and overall system changes over time, plus some understanding of the mechanisms involved which allow science-based predictions of the aged state of the units in future times. The NDE, D-test, and model results can also be used to assess statistically the reliability and performance of the overall aging population of units.

  7. The interaction of human endothelial cells with chemical gradient surfaces during exposure to flow

    NARCIS (Netherlands)

    Ruardy, TG; Moorlag, HE; Schakenraad, JM; Van der Meer, J; Van der Mei, HC; Busscher, HJ; Olij, WJV; Anderson, HR

    1998-01-01

    In this study, the position bound shape, spreading, detachment and migration of adhering HUVEC endothelial cells on dichlorodimethylsilane (DDS) chemical gradient surfaces was investigated during exposure to flow in a parallel plate flow chamber in the presence of` serum proteins. Gradient surfaces

  8. Supramolecular Assembly of Comb-like Macromolecules Induced by Chemical Reactions that Modulate the Macromolecular Interactions In Situ.

    Science.gov (United States)

    Xia, Hongwei; Fu, Hailin; Zhang, Yanfeng; Shih, Kuo-Chih; Ren, Yuan; Anuganti, Murali; Nieh, Mu-Ping; Cheng, Jianjun; Lin, Yao

    2017-08-16

    Supramolecular polymerization or assembly of proteins or large macromolecular units by a homogeneous nucleation mechanism can be quite slow and require specific solution conditions. In nature, protein assembly is often regulated by molecules that modulate the electrostatic interactions of the protein subunits for various association strengths. The key to this regulation is the coupling of the assembly process with a reversible or irreversible chemical reaction that occurs within the constituent subunits. However, realizing this complex process by the rational design of synthetic molecules or macromolecules remains a challenge. Herein, we use a synthetic polypeptide-grafted comb macromolecule to demonstrate how the in situ modulation of interactions between the charged macromolecules affects their resulting supramolecular structures. The kinetics of structural formation was studied and can be described by a generalized model of nucleated polymerization containing secondary pathways. Basic thermodynamic analysis indicated the delicate role of the electrostatic interactions between the charged subunits in the reaction-induced assembly process. This approach may be applicable for assembling a variety of ionic soft matters that are amenable to chemical reactions in situ.

  9. Characterization of hydroxyphenol-terminated alkanethiol self-assembled monolayers: interactions with phosphates by chemical force spectrometry.

    Science.gov (United States)

    Azmi, Alyza A; Ebralidze, Iraklii I; Dickson, Steven E; Horton, J Hugh

    2013-03-01

    Tannins and humic substances, commonly referred to as natural organic matter (NOM), constitute an important component of natural water and soil systems. These species contain numerous hydroxyl and carboxyl functional groups whose reactivity is strongly dependent on both the quantity and location of these moieties on the aromatic ring. In the present study, self-assembled monolayers (SAMs) of 4-(12-mercaptododecyl)benzene-1,2-diol (o-hydroxyphenol-terminated); 5-(12-mercaptododecyl)benzene-1,3-diol (m-hydroxyphenol-terminated); bis(11-thioundecyl) hydrogen phosphate (monoprotic phosphate); and 11-thioundecyl dihydrogen phosphate (diprotic phosphate) were prepared and characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflectance infrared spectroscopy (ATR-IR), and water contact angle measurements. The interactions between phenolic groups with phosphates were examined as a function of pH using the chemical force spectrometry (CFS) technique. The observations are discussed in the context of hydrogen bonding and electrostatic repulsion interaction between corresponding species. Adhesion force profiles of hydroxyphenol isomers interacting with monoprotic phosphate are dominated by ionic H-bonding; however the strength of o-hydroxyphenol interactions is significantly higher. The difference in location of hydroxyl groups on the interface also results in significantly different force-distance profiles for the isomeric hydroxyphenols when interacting with diprotic phosphate.

  10. Quantum Chemical Calculations on the Interaction between Flavonol and Functional Monomers (Methacrylic Acid and 4-Vinylpyridine in Molecularly Imprinted Polymers

    Directory of Open Access Journals (Sweden)

    Luis Enrique Gómez-Pineda

    2010-06-01

    Full Text Available Quantum chemical calculations were performed to characterize the interaction of the flavonol molecule (FL with methacrylic acid (MAA and 4-vinylpyridine (4VPy in the formation of imprinted polymers. The polarizable continuum model (PCM was used to gain insight on the type of interaction between the reactant molecules under vacuum conditions and in the presence of different solvents. The effect of solvent on the pre-polymerization complex formation was evaluated through the stability energy, in which chloroform behaves as the best solvent for the synthesis of the imprinted polymers since it facilitates the reaction by lowering its degree of stabilization. The reactivity was analyzed in terms of the electrostatic surface potential (ESP and Mulliken charge. By means of these results, it has been possible to determine two potential recognition sites for the interaction of the MAA monomer and one for the 4VPy in relation to the strength of interaction with FL. In this concern, the interaction of the system FL-MAA is stronger than FL-4VPy.

  11. Evaluating role of interactive visualization tool in improving students' conceptual understanding of chemical equilibrium

    Science.gov (United States)

    Sampath Kumar, Bharath

    The purpose of this study is to examine the role of partnering visualization tool such as simulation towards development of student's concrete conceptual understanding of chemical equilibrium. Students find chemistry concepts abstract, especially at the microscopic level. Chemical equilibrium is one such topic. While research studies have explored effectiveness of low tech instructional strategies such as analogies, jigsaw, cooperative learning, and using modeling blocks, fewer studies have explored the use of visualization tool such as simulations in the context of dynamic chemical equilibrium. Research studies have identified key reasons behind misconceptions such as lack of systematic understanding of foundational chemistry concepts, failure to recognize the system is dynamic, solving numerical problems on chemical equilibrium in an algorithmic fashion, erroneous application Le Chatelier's principle (LCP) etc. Kress et al. (2001) suggested that external representation in the form of visualization is more than a tool for learning, because it enables learners to make meanings or express their ideas which cannot be readily done so through a verbal representation alone. Mixed method study design was used towards data collection. The qualitative portion of the study is aimed towards understanding the change in student's mental model before and after the intervention. A quantitative instrument was developed based on common areas of misconceptions identified by research studies. A pilot study was conducted prior to the actual study to obtain feedback from students on the quantitative instrument and the simulation. Participants for the pilot study were sampled from a single general chemistry class. Following the pilot study, the research study was conducted with a total of 27 students (N=15 in experimental group and N=12 in control group). Prior to participating in the study, students have completed their midterm test on the topic of chemical equilibrium. Qualitative

  12. Dissecting the chemical interactions and substrate structural signatures governing RNA polymerase II trigger loop closure by synthetic nucleic acid analogues

    DEFF Research Database (Denmark)

    Xu, Liang; Butler, Kyle Vincent; Chong, Jenny

    2014-01-01

    The trigger loop (TL) of RNA polymerase II (Pol II) is a conserved structural motif that is crucial for Pol II catalytic activity and transcriptional fidelity. The TL remains in an inactive open conformation when the mismatched substrate is bound. In contrast, TL switches from an inactive open...... II. This study reveals novel insights into understanding the molecular basis of TL conformational transition upon substrate binding during Pol II transcription. This synthetic chemical biology approach may be extended to understand the mechanisms of other RNA polymerases as well as other nucleic acid...... state to a closed active state to facilitate nucleotide addition upon the binding of the cognate substrate to the Pol II active site. However, a comprehensive understanding of the specific chemical interactions and substrate structural signatures that are essential to this TL conformational change...

  13. Linking neuroethology to the chemical biology of natural products: interactions between cone snails and their fish prey, a case study.

    Science.gov (United States)

    Olivera, Baldomero M; Raghuraman, Shrinivasan; Schmidt, Eric W; Safavi-Hemami, Helena

    2017-05-27

    From a biological perspective, a natural product can be defined as a compound evolved by an organism for chemical interactions with another organism including prey, predator, competitor, pathogen, symbiont or host. Natural products hold tremendous potential as drug leads and have been extensively studied by chemists and biochemists in the pharmaceutical industry. However, the biological purpose for which a natural product evolved is rarely addressed. By focusing on a well-studied group of natural products-venom components from predatory marine cone snails-this review provides a rationale for why a better understanding of the evolution, biology and biochemistry of natural products will facilitate both neuroscience and the potential for drug leads. The larger goal is to establish a new sub-discipline in the broader field of neuroethology that we refer to as "Chemical Neuroethology", linking the substantial work carried out by chemists on natural products with accelerating advances in neuroethology.

  14. Physico-chemical and membrane-interacting properties of D-xylose-based bolaforms. Influence of the anomeric configuration.

    Directory of Open Access Journals (Sweden)

    Nasir M. N.

    2013-08-01

    Full Text Available Sugar-based biosurfactants such as xylose-derived bolaforms have interesting properties, for example high biocompatibility and biodegradability which make them potential useful molecules in the pharmaceutical and cosmetic fields. Until now, no detailed analyses of the physico-chemical properties of these compounds have been undertaken. Two symmetrical D-xylose-based bolaforms were chemically synthesized where the two xylose heads are linked via an acetal link to a hydrocarbon chain containing 18 carbon atoms and an unsaturation. The two bolaforms differ only by their anomeric configuration: αα or ββ. The αα bolaform exhibits interfacial properties at the air-water interface which is not the case for the ββ. FTIR spectroscopy showed that the interactions between the αα bolaform and POPC, a model phospholipid, involve the carbonyl groups of the phospholipid. .

  15. Chemical signals and their interactions change transpiration processes in tomato wild-type and flacca mutant

    DEFF Research Database (Denmark)

    Prokic, Ljiljana; Wollenweber, Bernd; Stikic, Radmila

    2011-01-01

    After the exposure to soil drying treatments, plants alkalize xylem sap. Xylem sap alkalization is not one a chemical signal per se, but it also facilitates the mobilization and redistribution of the phytohormone abscisic acid (ABA). Therefore, the objective of this paper was to investigate...... the effects of chemicalsignals on the mechanism of transpiration of isolated leaves of L. esculentum Mill. cv. Ailsa Craig (WT) and mutant flacca. In bioassays, exogenic activity of different ABA concentrations and pH were tested in both genotype of tomato in order to stimulate chemical signals occurring...... existed in flacca, when compared pH changed media with unchanged. Mutaul effects 10nM ABA and different pH on transpiration kinetics resulted in short and rapid stomatal closure. Similar interaction was obtained inflacca as slow phases of stomatal closure, but with a higher concentration of ABA (10m...

  16. Research review: interactions between environmental chemicals and drug biotransformation in man

    Energy Technology Data Exchange (ETDEWEB)

    Alvares, A.P.

    1978-11-01

    Besides genetic factors, environmental factors play a significant role in explaining the variation observed in the rates of drug metabolism between different individuals. Exposure to the heavy metal, lead, has been shown to inhibit drug metabolism; whereas intensive exposure to chlorinated insecticides has been shown to enhance the metabolism of test drugs such as antipyrine and phenylbutazone. An intentional source of exposure to foreign chemicals is cigarette smoke. Cigarette smoke contains polycyclic hydrocarbons, which are known inducers of hepatic mixed function oxidases. Pharmacokinetic studies have shown that cigarette smoking decreases the bioavailability of phenacetin and increases dosage requirements of theophylline by enhancing their rate of metabolism. Dietary factors may also play a significant role in the regulation of drug metabolism. Such intentional or unintentional exposure to environmental chemicals indicates the importance of individualisation of drug therapy.

  17. Using ANN to predict E. coli accumulation in coves based on interaction amongst various physical, chemical and biological factors

    Science.gov (United States)

    Dwivedi, D.; Mohanty, B. P.; Lesikar, B. J.

    2008-12-01

    The accumulation of Escherichia Coli (E. coli) in canals, coves and streams is the result of a number of interacting processes operating at multiple spatial and temporal scales. Fate and transport of E. coli in surface water systems is governed by different physical, chemical, and biological processes. Various models developed to quantify each of these processes occurring at different scales are not so far pooled into a single predictive model. At present, very little is known about the fate and transport of E. coli in the environment. We hypothesize that E. coli population heterogeneity in canals and coves is affected by physical factors (average stream width and/ depth, secchi depth, flow and flow severity, day since precipitation, aquatic vegetation, solar radiation, dissolved and total suspended solids etc.); chemical factors (basic water quality, nutrients, organic compounds, pH, and toxicity etc.); and biological factors (type of bacterial strain, predation, and antagonism etc.). The specific objectives of this study are to: (1) examine the interactions between E. coli and various coupled physical, chemical and biological factors; (2) examine the interactions between E. coli and toxic organic pollutants and other pathogens (viruses); and (3) evaluate qualitatively the removal efficiency of E. coli. We suggest that artificial neural networks (ANN) may be used to provide a possible solution to this problem. To demonstrate the application of the approach, we develop an ANN representing E. coli accumulation in two polluted sites at Lake Granbury in the upper part of the Brazos River in North Central Texas. The graphical structure of ANN explicitly represents cause- and-effect relationship between system variables. Each of these relationships can then be quantified independently using an approach suitable for the type and scale of information available. Preliminary results revealed that E. coli concentrations in canals show seasonal variations regardless of change

  18. Interaction of Ionizing Radiation, Genetically Active Chemicals, and Radiofrequency Radiation in Human and Rodent Cells

    Science.gov (United States)

    1990-12-01

    Martin L. Meltz, Ph.D. Patricia K. Holahan , Ph.D. Steven T. Smith, Ph.D. James J. Kerbacher, Ph.D. Victor Ciaravino, Ph.D. Department of Radiology PO...Chemicals, and Radiofrequency Radiation in Human and Rodent Cells 12 PERSONAL AUTHOR(S) Meltz. Martin L.; Holahan Patricia K.; Smith Steven Kerbacher...Potentiation of SCE Induction and Cell Killing by Adriamycin in CHO Cells (Ciaravino and Holahan , in preparation), showed that Adriamycin exposure at 410C

  19. Determination of specific binding interactions at L-cystine crystal surfaces with chemical force microscopy.

    Science.gov (United States)

    Mandal, Trinanjana; Ward, Michael D

    2013-04-17

    The pathogenesis of L-cystine kidney stones involves four critical steps: nucleation, crystal growth, crystal aggregation, and crystal adhesion to cells. Although inhibition of crystal growth by L-cystine "imposters" at L-cystine crystal surfaces has been suggested as a plausible route for the suppression of stones, understanding the factors that govern crystal-crystal aggregation and adhesion of crystals to epithelial cells also is essential for devising strategies to mitigate L-cystine stone formation. Chemical force microscopy performed with atomic force microscope tips decorated with functional groups commonly found in urinary constituents that likely mediate aggregation and attachment (e.g., COOH, NH2, SH, CH3, OH) revealed signatures that reflect differences in the chemical affinity of these groups for the (001) and {100} faces of the naturally occurring hexagonal form of L-cystine single crystals and the {110} faces of the non-native tetragonal form. These signatures can be explained by the different chemical compositions of the crystal faces, and they reveal a remarkable binding specificity of the thiol group for the sulfur-rich {100} and {110} faces of the hexagonal and tetragonal forms, respectively. Collectively, these observations suggest that alterations of the crystal habit and polymorph by crystal growth inhibitors may not affect crystal aggregation or adhesion to cells significantly.

  20. Chemical interactions between the present-day Martian atmosphere and surface minerals: Implications for sample return

    Science.gov (United States)

    Prinn, Ronald; Fegley, Bruce

    1988-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surface of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface materials. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible, however, to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation of the identity of its weathering parent mineral. The enormous advantages of studying the Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  1. The effect of interacting binaries on the chemical evolution of Globular Clusters

    CERN Document Server

    Vanbeveren, D; De Greve, J P

    2011-01-01

    The chemical processes during the Asymptotic Giant Branch (AGB) evolution of intermediate mass single stars (IMSSs) predict most of the observations of the different populations in globular clusters (GCs) although some important issues still need to be further clarified. In particular, to reproduce the observed anticorrelations of Na-O and Al-Mg and the helium distribution function, chemically enriched gas lost during the AGB phase of IMSSs must be mixed by pristine matter. The source of this pristine gas is still a matter of debate. Furthermore, observations reveal that a significant fraction of the intermediate mass and massive stars are born as components of close binaries. We will investigate the effects of binaries on the chemical evolution of GCs and on the origin of pristine matter that is needed for the single star AGB scenario to work. We use a population number synthesis code that accounts for all known binary physics in order to estimate the amount and the nature of the matter returned to the inter...

  2. University of California San Francisco (UCSF-1): Chemical-Genetic Interaction Mapping Strategy | Office of Cancer Genomics

    Science.gov (United States)

    The CTD2 Center at University of California San Francisco (UCSF-1) developed a chemical-genetic interaction mapping strategy to uncover the impact of cancer gene expression on responses to a panel of emerging therapeutics. To study the impact of aberrant gene activity in isolation, they developed an isogenic model of triple-negative breast cancer (TNBC) using the hormone receptor negative MCF10A non-tumorigenic cell line derived from healthy breast tissue which is diploid and largely devoid of somatic alterations.

  3. Experiments on interactions between zirconium-containing melt and water (ZREX). Hydrogen generation and chemical augmentation of energetics

    Energy Technology Data Exchange (ETDEWEB)

    Cho, D.H.; Armstrong, D.R.; Gunther, W.H. [Argonne National Lab., IL (United States); Basu, S.

    1998-01-01

    The results of the first data series of experiments on interactions between zirconium-containing melt and water are described. These experiments involved dropping 1-kg batches of pure zirconium or zirconium-zirconium dioxide mixture melt into a column of water. A total of nine tests were conducted, including four with pure zirconium melt and five with Zr-ZrO{sub 2} mixture melt. Explosions took place only in those tests which were externally triggered. While the extent of zirconium oxidation in the triggered experiments was quite extensive, the estimated explosion energetics were found to be very small compared to the combined thermal and chemical energy available. (author)

  4. Terpenes tell different tales at different scales: glimpses into the Chemical Ecology of conifer - bark beetle - microbial interactions.

    Science.gov (United States)

    Raffa, Kenneth F

    2014-01-01

    Chemical signaling mediates nearly all aspects of species interactions. Our knowledge of these signals has progressed dramatically, and now includes good characterizations of the bioactivities, modes of action, biosynthesis, and genetic programming of numerous compounds affecting a wide range of species. A major challenge now is to integrate this information so as to better understand actual selective pressures under natural conditions, make meaningful predictions about how organisms and ecosystems will respond to a changing environment, and provide useful guidance to managers who must contend with difficult trade-offs among competing socioeconomic values. One approach is to place stronger emphasis on cross-scale interactions, an understanding of which can help us better connect pattern with process, and improve our ability to make mechanistically grounded predictions over large areas and time frames. The opportunity to achieve such progress has been heightened by the rapid development of new scientific and technological tools. There are significant difficulties, however: Attempts to extend arrays of lower-scale processes into higher scale functioning can generate overly diffuse patterns. Conversely, attempts to infer process from pattern can miss critically important lower-scale drivers in systems where their biological and statistical significance is negated after critical thresholds are breached. Chemical signaling in bark beetle - conifer interactions has been explored for several decades, including by the two pioneers after whom this award is named. The strong knowledge base developed by many researchers, the importance of bark beetles in ecosystem functioning, and the socioeconomic challenges they pose, establish these insects as an ideal model for studying chemical signaling within a cross-scale context. This report describes our recent work at three levels of scale: interactions of bacteria with host plant compounds and symbiotic fungi (tree level

  5. Interaction of plasma-generated water cluster ions with chemically-modified Si surfaces investigated by infrared absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    Ayumi Hirano-Iwata

    2016-03-01

    Full Text Available We have investigated the interaction of water cluster ions generated by discharge plasma, with chemically modified Si surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. We observe that water cluster ions readily adsorb on SiO2-covered Si surfaces to form water droplets. We demonstrate that positively- and negatively-charged cluster ions adsorb on the SiO2-covered Si surface in different manners, indicating ionic interaction of the water droplets with the negatively-charged SiO2 surface. Water droplets formed on the protein-coated surface rupture the amide bond of the proteins, suggesting the function of protein decomposition of water cluster ions.

  6. Interaction of plasma-generated water cluster ions with chemically-modified Si surfaces investigated by infrared absorption spectroscopy

    Science.gov (United States)

    Hirano-Iwata, Ayumi; Matsumura, Ryosuke; Ma, Teng; Kimura, Yasuo; Niwano, Michio; Nishikawa, Kazuo

    2016-03-01

    We have investigated the interaction of water cluster ions generated by discharge plasma, with chemically modified Si surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. We observe that water cluster ions readily adsorb on SiO2-covered Si surfaces to form water droplets. We demonstrate that positively- and negatively-charged cluster ions adsorb on the SiO2-covered Si surface in different manners, indicating ionic interaction of the water droplets with the negatively-charged SiO2 surface. Water droplets formed on the protein-coated surface rupture the amide bond of the proteins, suggesting the function of protein decomposition of water cluster ions.

  7. Chemical and structural effects of invasive plants on herbivore-parasitoid/predator interactions in native communities

    NARCIS (Netherlands)

    Harvey, J.A.; Fortuna, T.

    2012-01-01

    The introduction and/or spread of exotic organisms into new habitats is considered a major threat to biodiversity. Invasive plants have been shown to negatively affect native communities, competing with and excluding other plants and disrupting a wide range of trophic interactions associated with

  8. Chemical and structural effects of invasive plants on herbivore-parasitoid/predator interactions in native communities

    NARCIS (Netherlands)

    Harvey, J.A.; Fortuna, T.

    2012-01-01

    The introduction and/or spread of exotic organisms into new habitats is considered a major threat to biodiversity. Invasive plants have been shown to negatively affect native communities, competing with and excluding other plants and disrupting a wide range of trophic interactions associated with th

  9. Structural and chemical evolution of single-wall carbon nanotubes under atomic and molecular deuterium interaction

    NARCIS (Netherlands)

    Lisowski, W.; Keim, E.G.; Berg, van den A.H.J.; Smithers, M.A.

    2005-01-01

    The interaction of atomic (D) and molecular (D2) deuterium, as present in a (D + D2) gas mixture, with single-wall carbon nanotubes (SWNTs) has been studied by means of a combination of scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The SWNT samp

  10. An apparatus for conducting physical, chemical, or biological interaction between gases and solid particles

    DEFF Research Database (Denmark)

    2013-01-01

    The invention provides an apparatus for conducting interaction between gases and solid particles. The apparatus has a vertical hollow shaft with a vertical row of constrictions formed internally and defining a series of intercommunicating chambers in the shaft for guiding the gas and particles e....

  11. Interaction of anthraquinone anti-cancer drugs with DNA:Experimental and computational quantum chemical study

    Science.gov (United States)

    Al-Otaibi, Jamelah S.; Teesdale Spittle, Paul; El Gogary, Tarek M.

    2017-01-01

    Anthraquinones form the basis of several anticancer drugs. Anthraquinones anticancer drugs carry out their cytotoxic activities through their interaction with DNA, and inhibition of topoisomerase II activity. Anthraquinones (AQ4 and AQ4H) were synthesized and studied along with 1,4-DAAQ by computational and experimental tools. The purpose of this study is to shade more light on mechanism of interaction between anthraquinone DNA affinic agents and different types of DNA. This study will lead to gain of information useful for drug design and development. Molecular structures were optimized using DFT B3LYP/6-31 + G(d). Depending on intramolecular hydrogen bonding interactions two conformers of AQ4 were detected and computed as 25.667 kcal/mol apart. Molecular reactivity of the anthraquinone compounds was explored using global and condensed descriptors (electrophilicity and Fukui functions). Molecular docking studies for the inhibition of CDK2 and DNA binding were carried out to explore the anti cancer potency of these drugs. NMR and UV-VIS electronic absorption spectra of anthraquinones/DNA were investigated at the physiological pH. The interaction of the three anthraquinones (AQ4, AQ4H and 1,4-DAAQ) were studied with three DNA (calf thymus DNA, (Poly[dA].Poly[dT]) and (Poly[dG].Poly[dC]). NMR study shows a qualitative pattern of drug/DNA interaction in terms of band shift and broadening. UV-VIS electronic absorption spectra were employed to measure the affinity constants of drug/DNA binding using Scatchard analysis.

  12. The Complex Physical-Chemical Interaction of Fracking Fluids with Gas Shale

    Science.gov (United States)

    Cathles, L. M.; Engelder, T.; Bryndzia, T.

    2014-12-01

    The chemical aspects of hydrofracturing might seem straight forward: Inject a fluid with sand and some chemicals, recover the injected water now contaminated with chemicals from the shale, and produce gas. But there are some complications that turn out to be very interesting. First of all, it is possible to recover only about 20% of the injected water. Secondly, the fresh injected water (1-5 kppm) has been turned into a very saline bine (~200 kppm). It's easy to say the water has just been imbibed into the gas-filled dry shale, like water into a dry sponge, except the organic parts of the shale which host nearly all the porosity are hydrophobic. The shale is strongly oil wet; nevertheless it imbibes water. It's easy to say the water just mixed with water in the shale and became salty, but there is almost no water in the shale, and no salt either. How the water becomes salty begs easy explanation. The talk will quantitatively discuss these issues in light of experiments we have carried out, concluding that powerful capillary and osmotic forces draw fracking water into the shale while making the return waters salty. How this is achieved will certainly tell us something about the fracture network and its connections. The practical implication is that hydrofracture fluids will be locked into the same "permeability jail" that sequestered overpressured gas for over 200 million years. If one wants to dispose of fracking waters, one could probably not choose a safer way to do so that to inject them into a gas shale.

  13. Organic semiconductor/gold interface interactions: from physisorption on planar surfaces to chemical reactions with metal nanoparticles.

    Science.gov (United States)

    Ligorio, Giovanni; Nardi, Marco Vittorio; Christodoulou, Christos; Koch, Norbert

    2015-08-24

    The interaction of gold nanoparticles (AuNPs) with prototypical organic semiconductors used in optoelectronics, namely, tris(8-hydroxyquinoline)aluminium (Alq3 ) and 4,4-bis[N-(1-naphthyl)-N-phenylamino]diphenyl (α-NPD), is investigated in situ by X-ray photoelectron spectroscopy (XPS). These AuNPs-on-molecule experiments are compared with the reversed molecule-on-Au cases. The molecules-on-Au systems show only weak interactions, and the evolution of the XP spectra is dominated by final-state effects. In contrast, in the AuNPs-on-molecules cases, both initial-state effects and final-state effects occur. Spectral features arising for both molecules and metal indicate charge transfer and the formation of organometallic complexes (initial-state effects). The energy shift in the metal emission underlines the size-induced nanometric nature of the molecule/Au interaction (final-state effects). Consequently, the chemical interaction between metals and organic semiconductors likely depends strongly on the deposition sequence in general.

  14. Chemical and mechanical interactions of interstitials in V-5%Cr-5%Ti

    Energy Technology Data Exchange (ETDEWEB)

    DeVan, J.H.; DiStefano, J.R.; Hendricks, J.W. [Oak Ridge National Lab., TN (United States)] [and others

    1995-04-01

    A vanadium alloy structure with liquid lithium is the favored concept for an advanced breeding blanket for ITER. The objective of this task is to determine the kinetics of reactions of vanadium alloys with hydrogen and oxygen as a function of alloy composition and TMT. Gas-metal reaction studies of V-5Cr-5Ti were conducted to determine the kinetics of reactions with H{sub 2} and O{sub 2}, respectively, at 450-500{degree}C. Reaction rates were determined through wieght change measurements and chemical analyses, and effects on mechanical properties were evaluated by room temperature tensile tests.

  15. A quantitative analysis of weak intermolecular interactions & quantum chemical calculations (DFT) of novel chalcone derivatives

    Science.gov (United States)

    Chavda, Bhavin R.; Gandhi, Sahaj A.; Dubey, Rahul P.; Patel, Urmila H.; Barot, Vijay M.

    2016-05-01

    The novel chalcone derivatives have widespread applications in material science and medicinal industries. The density functional theory (DFT) is used to optimized the molecular structure of the three chalcone derivatives (M-I, II, III). The observed discrepancies between the theoretical and experimental (X-ray data) results attributed to different environments of the molecules, the experimental values are of the molecule in solid state there by subjected to the intermolecular forces, like non-bonded hydrogen bond interactions, where as isolated state in gas phase for theoretical studies. The lattice energy of all the molecules have been calculated using PIXELC module in Coulomb -London -Pauli (CLP) package and is partitioned into corresponding coulombic, polarization, dispersion and repulsion contributions. Lattice energy data confirm and strengthen the finding of the X-ray results that the weak but significant intermolecular interactions like C-H…O, Π- Π and C-H… Π plays an important role in the stabilization of crystal packing.

  16. Analysis of Protein–Protein Interactions in MCF-7 and MDA-MB-231 Cell Lines Using Phthalic Acid Chemical

    Directory of Open Access Journals (Sweden)

    Shih-Shin Liang

    2014-11-01

    Full Text Available Phthalates are a class of plasticizers that have been characterized as endocrine disrupters, and are associated with genital diseases, cardiotoxicity, hepatotoxicity, and nephrotoxicity in the GeneOntology gene/protein database. In this study, we synthesized phthalic acid chemical probes and demonstrated differing protein–protein interactions between MCF-7 cells and MDA-MB-231 breast cancer cell lines. Phthalic acid chemical probes were synthesized using silicon dioxide particle carriers, which were modified using the silanized linker 3-aminopropyl triethoxyslane (APTES. Incubation with cell lysates from breast cancer cell lines revealed interactions between phthalic acid and cellular proteins in MCF-7 and MDA-MB-231 cells. Subsequent proteomics analyses indicated 22 phthalic acid-binding proteins in both cell types, including heat shock cognate 71-kDa protein, ATP synthase subunit beta, and heat shock protein HSP 90-beta. In addition, 21 MCF-7-specific and 32 MDA-MB-231 specific phthalic acid-binding proteins were identified, including related proteasome proteins, heat shock 70-kDa protein, and NADPH dehydrogenase and ribosomal correlated proteins, ras-related proteins, and members of the heat shock protein family, respectively.

  17. Effect of n-Al2O3 on electrochemical nucleation and chemical binding interaction in nickel electrodeposition

    Institute of Scientific and Technical Information of China (English)

    TU Wei-yi; XU Bin-shi; DONG Shi-yun; JIANG Bin; DU Ling-zhong

    2005-01-01

    The electrochemical nucleation mechanism of nickel on the vitreous carbon electrode from n-Al2 Os/Ni composite brush plating system was investigated using potential step method. The interaction between nano-alumina and matrix metal was researched by X-ray photoelectron spectrometry. The results show that the nano-alumina leads to the increasing of the nuclei density, nucleation rate constant and crystal growth rate during nickel electrocrystallization. Nano-alumina is found to be beneficial for nucleation and growth of nickel. During the electrodeposition process, some nanoparticles are captured effectively on the growing metal surface. As the absorbed nickel atoms are diffusing on electrode surface, some of them arrive at the interface between the captured nano-alumina and the growing metal surface. The unsaturated bond of oxygen on nano-alumina surface can capture some of the absorbed nickel atoms and form nickel-oxygen chemical bond. The new nucleation and growth sites of nickel atoms appear at the interfaces between nanoparticles and metal growing surface. Nanoparticles are embedded gradually in the newly deposited nickel atoms, which leads to the formation of the composite coating. The results indicate that the nano-alumina takes part in the electrode reaction and the unsaturated chemical bond of oxygen on nanoparticle surface can combine with the absorbed nickel atoms by way of chemical bond.

  18. Wrapping of a single bacterium with Functionalized - Chemically Modified Graphene (FCMG) sheets via highly specific protein-cell wall interaction

    Science.gov (United States)

    Mohanty, Nihar; Berry, Vikas

    2009-03-01

    Graphene has recently generated a lot of interest due to its unique structural and electrical properties. It's micro-scale area and sub-nano-scale thickness coupled with ballistic electronic transport at room temperature, low Johnston noise and low charge scattering, have made it a gold mine for novel applications. Since its discovery in 2004, there have been a plethora of studies on characterizing its unique physical, chemical and electrical properties of graphene as well as on integrating it with various physical/chemical systems to utilize these properties. But there have been limited or no studies on the integration of graphene with living microorganisms or mammalian cells. Here we describe the novel wrapping of a single live bacterium (Bacillus cereus) with a chemically modified graphene sheet functionalized with the protein Concanavalin-A (Con-A) via the highly specific Con-A - Teichoic acid interaction. We are investigating the structural and the electrical properties of these novel bacteria-FCMG ensembles. Further, we are also interested in characterizing this wrapping process in detail by studying the kinetics and the mechanism of action of bacterial-wrapping via 3D modelling. This is a first step towards the live-bio-nano-integration of graphene which would open up avenues for applications as diverse as bio-batteries using the Geobacter to recombinant enzyme compartmentalization.

  19. Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wilmsmeyer, Amanda R.; Morris, John R. [Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States); Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A. [Research and Technology Directorate, U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 (United States); Davis, Erin Durke [OptiMetrics, Inc., Abingdon, Maryland 21009 (United States)

    2014-01-15

    A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

  20. Deciphering chemical interactions between Glycyrrhizae Radix and Coptidis Rhizoma by liquid chromatography with transformed multiple reaction monitoring mass spectrometry.

    Science.gov (United States)

    Li, Zhenhao; Liu, Ting; Liao, Jie; Ai, Ni; Fan, Xiaohui; Cheng, Yiyu

    2017-01-18

    In this study, we propose an integrated strategy for the efficient identification and quantification of herbal constituents using liquid chromatography with mass spectrometry. First, liquid chromatography with quadrupole time-of-flight mass spectrometry was employed for the chemical profiling of herbs, where a targeted following nontargeted approach was developed to detect trace constituents by using structural correlations and extracted ion chromatograms. Next, ion pairs and parameters of MS(2) of quadrupole time-of-flight mass spectrometry were selected to design multiple reaction monitoring transitions for the identified compounds on liquid chromatography with triple quadrupole mass spectrometry. The relative concentration of each constituent was then calculated using a semiquantitative calibration curve. The proposed strategy was applied in a study of chemical interactions between Glycyrrhizae Radix and Coptidis Rhizoma. A total of 140 compounds were identified or tentatively characterized from the herbs, 132 of which were relatively quantified. The visualized quantitative results clearly showed codecoction produced significant constituent concentration variations especially for those with a low polarity. The case study also indicated that the present methodology could provide a reliable, accurate, and labor-saving solution for chemical studies of herbal medicines.

  1. Intermolecular Interactions in Crystalline Theobromine as Reflected in Electron Deformation Density and (13)C NMR Chemical Shift Tensors.

    Science.gov (United States)

    Bouzková, Kateřina; Babinský, Martin; Novosadová, Lucie; Marek, Radek

    2013-06-11

    An understanding of the role of intermolecular interactions in crystal formation is essential to control the generation of diverse crystalline forms which is an important concern for pharmaceutical industry. Very recently, we reported a new approach to interpret the relationships between intermolecular hydrogen bonding, redistribution of electron density in the system, and NMR chemical shifts (Babinský et al. J. Phys. Chem. A, 2013, 117, 497). Here, we employ this approach to characterize a full set of crystal interactions in a sample of anhydrous theobromine as reflected in (13)C NMR chemical shift tensors (CSTs). The important intermolecular contacts are identified by comparing the DFT-calculated NMR CSTs for an isolated theobromine molecule and for clusters composed of several molecules as selected from the available X-ray diffraction data. Furthermore, electron deformation density (EDD) and shielding deformation density (SDD) in the proximity of the nuclei involved in the proposed interactions are calculated and visualized. In addition to the recently reported observations for hydrogen bonding, we focus here particularly on the stacking interactions. Although the principal relations between the EDD and CST for hydrogen bonding (HB) and stacking interactions are similar, the real-space consequences are rather different. Whereas the C-H···X hydrogen bonding influences predominantly and significantly the in-plane principal component of the (13)C CST perpendicular to the HB path and the C═O···H hydrogen bonding modulates both in-plane components of the carbonyl (13)C CST, the stacking modulates the out-of-plane electron density resulting in weak deshielding (2-8 ppm) of both in-plane principal components of the CST and weak shielding (∼ 5 ppm) of the out-of-plane component. The hydrogen-bonding and stacking interactions may add to or subtract from one another to produce total values observed experimentally. On the example of theobromine, we demonstrate

  2. Chemical interactions in complex matrices: Determination of polar impurities in biofuels and fuel contaminants in building materials

    Science.gov (United States)

    Baglayeva, Ganna

    The solutions to several real-life analytical and physical chemistry problems, which involve chemical interactions in complex matrices are presented. The possible interferences due to the analyte-analyte and analyte-matrix chemical interactions were minimized on each step of the performed chemical analysis. Concrete and wood, as major construction materials, typically become contaminated with fuel oil hydrocarbons during their spillage. In the catastrophic scenarios (e.g., during floods), fuel oil mixes with water and then becomes entrained within the porous structure of wood or concrete. A strategy was proposed for the efficient extraction of fuel oil hydrocarbons from concrete to enable their monitoring. The impacts of sample aging and inundation with water on the extraction efficiency were investigated to elucidate the nature of analytematrix interactions. Two extraction methods, 4-days cold solvent extraction with shaking and 24-hours Soxhlet extraction with ethylacetate, methanol or acetonitrile yielded 95-100 % recovery of fuel oil hydrocarbons from concrete. A method of concrete remediation after contamination with fuel oil hydrocarbons using activated carbon as an adsorbent was developed. The 14 days remediation was able to achieve ca. 90 % of the contaminant removal even from aged water-submerged concrete samples. The degree of contamination can be qualitatively assessed using transport rates of the contaminants. Two models were developed, Fickian and empirical, to predict long-term transport behavior of fuel oil hydrocarbons under flood representative scenarios into wood. Various sorption parameters, including sorption rate, penetration degree and diffusion coefficients were obtained. The explanations to the observed three sorption phases are provided in terms of analyte-matrix interactions. The detailed simultaneous analysis of intermediate products of the cracking of triacylglycerol oils, namely monocarboxylic acids, triacyl-, diacyl- and

  3. Interaction between measurement time and observed Hugoniot cusp due to chemical reactions

    Science.gov (United States)

    McGrane, S. D.; Brown, K. E.; Bolme, C. A.; Moore, D. S.

    2017-01-01

    Chemistry occurring on picosecond timescales can be observed through ultrafast laser shock drive experiments that measure Hugoniot data and transient absorption. The shock stress needed to induce chemical reactions on picosecond time scales is significantly larger than the stress needed to induce reactions on nanosecond time scales typical of gas gun and explosively driven plate impact experiments. This discrepancy is consistent with the explanation that increased shock stress leads to increased temperature, which drives thermally activated processes at a faster rate. While the data are qualitatively consistent with the interpretation of thermally dominated reactions, they are not a critical test of this interpretation. In this paper, we review data from several shocked liquids that illustrate a Hugoniot cusp due to volume changing reactions that occurs at higher shock stress states in picosecond experiments than in nanosecond to microsecond experiments. We also correlate the observed Hugoniot cusp states with transient absorption changes that occur due to the buildup of reaction products.

  4. Water/Rock Interactions and Changes in Chemical Composition During Zeolite Mineralization

    Institute of Scientific and Technical Information of China (English)

    张寿庭; 赵鹏大; 徐旃章; 郑明华

    2001-01-01

    Systematic analysis and comparative study of the chemical compositions of rocks and ores from the main types of zeolite deposits in the surroundings of the Songliao Basin have shown that the process of formation of zeolite from volcanic and pyroclastic rocks is generally characterized by the relative purification of SiO2, i.e., SiO2/A12O3 ratios tend to increase, al kali earth elements (CaO + MgO) and H2O are relatively enriched, and the alkali metals (K2O + Na2O) are depleted in their total amount. The alkali metals K and Na follow different rules of migration and enrichment during the formation of mordenite and clinoptilolite. In the pro cess of formation of mordenite more Na+ will be imported and K+ will be lost remarkably. On the contrary, in the process of formation clinoptilolite more K+ will be incorporated and Na+will become obviously depleted.

  5. HM+ and HM+-He (M = Group 2 metal): Chemical or physical interactions?

    Science.gov (United States)

    Harris, Joe P.; Dodson, Hannah; Breckenridge, W. H.; Wright, Timothy G.

    2014-09-01

    We investigate the HM+-He complexes (M = Group 2 metal) using quantum chemistry. Equilibrium geometries are linear for M = Be and Mg, and bent for M = Ca-Ra; the explanation for this lies in the differing nature of the highest occupied molecular orbitals in the two sets of complexes. The difference primarily occurs as a result of the formation of the H-M+ bond, and so the HM+ diatomics are also studied as part of the present work. The position of the He atom in the complexes is largely determined by the form of the electron density. HM+…He binding energies are obtained and are surprisingly high for a helium complex. The HBe+…He value is almost 3000 cm-1, which is high enough to suspect contributions from chemical bonding. This is explored by examining the natural orbital density and by population analyses.

  6. The Ehrenfest force topology: a physically intuitive approach for analyzing chemical interactions.

    Science.gov (United States)

    Maza, Julio R; Jenkins, Samantha; Kirk, Steven R; Anderson, James S M; Ayers, Paul W

    2013-11-07

    Modified ANO-RCC basis sets are used to determine twelve molecular graphs of the Ehrenfest force for H2, CH4, CH2O, CH3NO, C2H2, C2H4, C3H3NO, N4H4, H2O, (H2O)2, (H2O)4 and (H2O)6. The molecular graphs include all types of topological critical points and a mix of bonding types is chosen to include sigma-, π- and hydrogen-bonding. We then compare a wide range of point properties: charge density, trace of the Hessian, eigenvalues, ellipticity, stiffness, total local energy and the eigenvectors are calculated at the bond critical points (BCPs) and compared for the Ehrenfest, QTAIM and stress tensor schemes. QTAIM is found to be the only partitioning scheme that can differentiate between shared- and closed-shell chemical bond types. Only the results from the Ehrenfest force partitioning, however, are demonstrated to be physically intuitive. This is demonstrated for the water molecule, the water-dimer and the water clusters (H2O)4 and (H2O)6. In particular, both the stiffness and the trace of the Hessians of the appropriate quantities of the sigma-bond BCPs for the water clusters are found to depend on the quantum topology dimension of the molecular graph. The behavior of all the stress tensor point properties is found to be erratic. This is explained by the ambiguity in the theoretical definition of the stress tensor. As a complementary approach the Ehrenfest force provides a new indicator of the mixed chemical character of the hydrogen-bond BCP, which arises from the collinear donor sigma-bond donating a degree of covalent character to the hydrogen-bond. This indicator takes the form of the relative orientation of the shallowest direction of the Ehrenfest potential of the hydrogen-bond BCPs and the corresponding direction for the collinear sigma-bond BCP.

  7. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  8. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    Science.gov (United States)

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-06-02

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  9. INTERACTION OF SULPHUR WITH BIMETALLIC SURFACES: EFFECTS OF STRUCTURAL, ELECTRONIC AND CHEMICAL PROPERTIES.

    Energy Technology Data Exchange (ETDEWEB)

    RODRIGUEZ,J.A.; HRBEK,J.

    2001-10-04

    In recent years, several new interesting phenomena have been discovered when studying the interaction of sulphur with bimetallic surfaces using the modern techniques of surface science. Very small amounts of sulphur can induce dramatic changes in the morphology of bimetallic surfaces. The electronic perturbations associated with the formation of a heteronuclear metal-metal bond affect the reactivity of the bonded metals toward sulphur. This can be a very important issue to consider when trying to minimize the negative effects of sulphur poisoning or dealing with the design of desulfurization catalysts.

  10. A quantitative analysis of weak intermolecular interactions & quantum chemical calculations (DFT) of novel chalcone derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Chavda, Bhavin R., E-mail: chavdabhavin9@gmail.com; Dubey, Rahul P.; Patel, Urmila H. [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388120, Gujarat (India); Gandhi, Sahaj A. [Bhavan’s Shri I.L. Pandya Arts-Science and Smt. J.M. shah Commerce College, Dakar, Anand -388001, Gujarat, Indian (India); Barot, Vijay M. [P. G. Center in Chemistry, Smt. S. M. Panchal Science College, Talod, Gujarat 383 215 (India)

    2016-05-06

    The novel chalcone derivatives have widespread applications in material science and medicinal industries. The density functional theory (DFT) is used to optimized the molecular structure of the three chalcone derivatives (M-I, II, III). The observed discrepancies between the theoretical and experimental (X-ray data) results attributed to different environments of the molecules, the experimental values are of the molecule in solid state there by subjected to the intermolecular forces, like non-bonded hydrogen bond interactions, where as isolated state in gas phase for theoretical studies. The lattice energy of all the molecules have been calculated using PIXELC module in Coulomb –London –Pauli (CLP) package and is partitioned into corresponding coulombic, polarization, dispersion and repulsion contributions. Lattice energy data confirm and strengthen the finding of the X-ray results that the weak but significant intermolecular interactions like C-H…O, Π- Π and C-H… Π plays an important role in the stabilization of crystal packing.

  11. Long-term simulation of large deformation, mechano-chemical fluid-structure interactions in ALE and fully Eulerian coordinates

    Science.gov (United States)

    Frei, S.; Richter, T.; Wick, T.

    2016-09-01

    In this work, we develop numerical schemes for mechano-chemical fluid-structure interactions with long-term effects. We investigate a model of a growing solid interacting with an incompressible fluid. A typical example for such a situation is the formation and growth of plaque in blood vessels. This application includes two particular difficulties: First, growth may lead to very large deformations, up to full clogging of the fluid domain. We derive a simplified set of equations including a fluid-structure interaction system coupled to an ODE model for plaque growth in Arbitrary Lagrangian Eulerian (ALE) coordinates and in Eulerian coordinates. The latter novel technique is capable of handling very large deformations up to contact. The second difficulty stems from the different time scales: while the dynamics of the fluid demand to resolve a scale of seconds, growth typically takes place in a range of months. We propose a temporal two-scale approach using local small-scale problems to compute an effective wall stress that will enter a long-scale problem. Our proposed techniques are substantiated with several numerical tests that include comparisons of the Eulerian and ALE approaches as well as convergence studies.

  12. A study on chemical interactions between waste fluid, formation water, and host rock during deep well injection

    Energy Technology Data Exchange (ETDEWEB)

    Spycher, Nicolas; Larkin, Randy

    2004-05-14

    A new disposal well was drilled in the vicinity of an injection well that had been in operation for 12 years. The drilling activities provided an opportunity to assess the fate and transport of waste products injected in the nearby well, and the impact, if any, on the host geologic formation. The origin of the fluid collected while drilling the new well and the interaction between injected waste and the formation were investigated using analyses of formation waters, waste, and formation minerals, by applying traditional graphical methods and sophisticated numerical models. This approach can be used to solve a wide range of geochemical problems related to deep well injection of waste. Trilinear Piper diagrams, Stiff diagrams, and correlation plots show that the chemical characteristics of recovered fluid at the new well are similar to those of formation water. The concentrations of most major constituents in the fluid appear diluted when compared to formation water sampled at other locations. This could be explained by mixing with waste, which is less saline than formation water. However, the waste injected near the new well consists primarily of ammonia and sulfate, and these waste constituents are not found at concentrations elevated enough to suggest that significant mixing of formation water with waste has occurred. To determine whether chemical interactions between injected waste and formation could explain the chemistry of fluid recovered from the new well, we simulated the chemical reaction between waste, formation water, and the formation rock by numerical modeling. Initial modeling calculations were done using a multicomponent geochemical reaction-path model to simulate fresh waste reacting with the formation. A more complex simulation coupling flow, transport, and reaction was then run using a multicomponent geochemical reactive transport model. These numerical simulations were carried out to calculate porosity changes and evaluate chemical processes

  13. Minimally-Invasive Gene Transfection by Chemical and Physical Interaction of Atmospheric Pressure Plasma Flow

    Science.gov (United States)

    Kaneko, Toshiro

    2014-10-01

    Non-equilibrium atmospheric pressure plasma irradiated to the living-cell is investigated for medical applications such as gene transfection, which is expected to play an important role in molecular biology, gene therapy, and creation of induced pluripotent stem (iPS) cells. However, the conventional gene transfection using the plasma has some problems that the cell viability is low and the genes cannot be transferred into some specific lipid cells, which is attributed to the unknown mechanism of the gene transfection using the plasma. Therefore, the time-controlled atmospheric pressure plasma flow is generated and irradiated to the living-cell suspended solution for clarifying the transfection mechanism toward developing highly-efficient and minimally- invasive gene transfection system. In this experiment, fluorescent dye YOYO-1 is used as the simulated gene and LIVE/DEAD Stain is simultaneously used for cell viability assay. By the fluorescence image, the transfection efficiency is calculated as the ratio of the number of transferred and surviving cells to total cell count. It is clarified that the transfection efficiency is significantly increased by the short-time (cell viability (>90%). This result indicates that the physical effects such as the electric field caused by the charged particles arriving at the surface of the cell membrane, and chemical effects associated with plasma-activated products in solution act synergistically to enhance the cell-membrane transport with low-damage. This work was supported by JSPS KAKENHI Grant Number 24108004.

  14. Balance between physical and chemical interactions of second-row diatomic molecules with graphene sheet

    Science.gov (United States)

    Rahali, Seyfeddine; Belhocine, Youghourta; Touzeau, Jeremy; Tangour, Bahoueddine; Maurel, François; Seydou, Mahamadou

    2017-02-01

    We present a computational investigation of adsorption on graphene concerning the second-row diatomic molecules (Li2, B2, C2, O2, N2 and F2). The adsorption energies and the nature of the interaction between guest molecules and graphene, in both periodic and non-periodic approaches, were evaluated using dispersion-corrected density functional theory calculations (DFT/PBE-D3). A periodic graphene model, used to tune the coverage, is compared with a cluster model in which the graphene sheet is represented by coronene. The results of both energetic and electronic state analyses reveal a variety of adsorption processes. While B2 and C2 adsorb in a bridge position in order to establish two covalent bonds with the surface, O2 and N2 are clearly physisorbed in positions parallel to the surface. Li2 and F2 show intermediate behavior, with strong physisorption accompanied by charge transfer.

  15. Prediction of bioactive compound pathways using chemical interaction and structural information.

    Science.gov (United States)

    Cheng, Shiwen; Zhu, Changming; Chu, Chen; Huang, Tao; Kong, Xiangyin; Zhu, Liu Cun

    2016-01-01

    The functional screening of compounds is an important topic in chemistry and biomedicine that can uncover the essential properties of compounds and provide information concerning their correct use. In this study, we investigated the bioactive compounds reported in Selleckchem, which were assigned to 22 pathways. A computational method was proposed to identify the pathways of the bioactive compounds. Unlike most existing methods that only consider compound structural information, the proposed method adopted both the structural and interaction information from the compounds. The total accuracy achieved by our method was 61.79% based on jackknife analysis of a dataset of 1,832 bioactive compounds. Its performance was quite good compared with that of other machine learning algorithms (with total accuracies less than 46%). Finally, some of the false positives obtained by the method were analyzed to investigate the likelihood of compounds being annotated to new pathways.

  16. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    Science.gov (United States)

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  17. Physical, chemical, and thermal interactions in the Pleasant Bay Layered Gabbro-Diorite Intrusion, Maine

    Science.gov (United States)

    Patwardhan, K.; Algeo, J.

    2012-12-01

    density differences together with field measurements of pipe radii and spacing. Rapid solidification of the gabbro along its lower contact accompanied by an increase in viscosity slowed down the ascent of the pipes and ultimately arrested them in their present state. Petrographic analyses of samples taken across the gabbro-diorite contacts and pipe-gabbro contacts indicate significant differences in the occurrence and abundance of hydrous phases, notably biotite and hornblende, between the chilled gabbro contacts and bulk of the gabbro, the underlying diorite, and the pipes. SEM-EDS analyses also reveal changes in mineral compositions within a few mm of the pipe-gabbro and gabbro-diorite contacts (e.g. drop in plagioclase An content in chilled gabbro surrounding pipes). These observations suggest transfer of water from the diorite and/or pipes into anhydrous gabbro as well as physical transfer of crystals across these boundaries. Quantifying the mineral and chemical differences along the pipe-gabbro and gabbro-diorite contacts in the context of the timescales of R-T instability and solidification reveal the in situ rates of physical and chemical exchange between these magmas. (Special thanks to Dr. Robert Wiebe for assistance with fieldwork, and to Dr. Chris Daniel for assistance with SEM analyses.)

  18. Use of detailed thermochemical databases to model chemical interactions in the Severe Accident codes

    Energy Technology Data Exchange (ETDEWEB)

    Barrachin, M. [IPSN/DRS, CEA Cadarache (France)

    2001-07-01

    For the prevention, mitigation and management of severe accidents, many problems related to core melt have to be solved: fuel degradation, melting and relocation, convection in the core melt(s), coolability of the core melt(s), fission product release, hydrogen production, behavior of the materials of the protective layers, ex-vessel spreading of the core melt(s).. To solve these problems such properties like thermal conductivity, heat capacity, density, viscosity, evaporation or sublimation of melts, the solidification behavior (solid/liquid fraction), the tendency to trap or to release the fission products, the stratification of melts notably metallic and oxide, must be known. However most of these properties are delicate to measure directly at high temperature and/or in the radio-active environment produced by the fission products. Therefore some of them must be derived by calculations from the physical-chemical description of the melt: number of phases, phase compositions, proportions of solids and liquids and their respective oxidation state, miscibility of the liquids, solubility of one phase in another, etc. This information is given by the phase diagrams of the materials in presence. Since more than ten years, IPSN has developed in collaboration with THERMODATA (Grenoble, France) a very detailed thermochemical database for the complex system U-O-Zr-Fe-Ni-La-Ba-Ru-Sr-Si-Mg-Ca-Al-(H-Ar). The direct coupling between the severe accident (SA) Codes and a thermochemical code with its database is not actually possible because of the computer time consuming and the size of the database. For this reason, most of the Severe Accident codes usually have a very simplified description for the phase diagrams which are not in agreement with the status of the art. In this presentation, alternative methodologies are detailed with their respective difficulties, the goal being to build an interface between a thermochemical database and a SA Code and to get a fast, accurate and

  19. Biological and chemical interactions excelerating the removal of impurities from fly ashes

    Directory of Open Access Journals (Sweden)

    Štyriaková Iveta

    2002-03-01

    Full Text Available The mesophilic bacteria were isolated from the deposit of fly ash in Chalmová (Slovakia and identified using the BBL identification system. Bacillus cereus was the dominant species in this deposit of aluminosilicate minerals. Under laboratory conditions , Bacillus cereus accelerated the extraction of major and trace impurities in fly ash during bioleaching processes. This process was dependent on bacterial adhesion and production of organic acids. The effect of organic acids produced by bacteria was detected especially in sites where impregnated metals were found in the aluminosilicate structure. Amorphous spherical aluminosilicate particles in allotriomorphic aluminosilicate grains represent a main mineral component of fly-ash in which also elements such as Fe, Ti, Mn, As are bound. The rate of mobilization of Al, Si and Ti from coal fly ash under biochemically relevant conditions in vitro was previously shown to depend on the quantity of the ash microspheres. The qualitative EDS analyse of leachates confirmed the extraction of toxic elements (As and Mn from the initial sample of fly ash.Heterotrophic bacteria of Bacillus genus are capable to remove impurities from deposited fly-ash. A long-term deposition of energy fly-ash causes chemical and mineralogical changes as a result of weathering processes. Depending on the composition of coal concentrate containing SiO2, Al2O3, Fe2O3, CaO, MgO and other oxides, fly ash can provide a useful preliminary batch for the preparation of glass-ceramics or zeolite after extracting of bacterially dissolved elements from it. The mobility of major impurities (Ca and Fe and heavy metals, caused by biochemical leaching of fly ash, suggests the possibility of the development of an alternative way of this raw material treatment. The advantage of bioleaching is relatively low cost and the subsequent low demand for energy compared with conventional technologies.

  20. Report of Iridium/{sup 238}PuO{sub 2} Compatibility Test

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D.H.

    2001-08-09

    This study indicates that the chemical purity of the fuel used presently to fabricate fueled clad vent sets will not present any special problems to the performance of the fueled clad vent sets as intended. However, cation impurities in the fuel can have a deleterious effect on the iridium cladding and vents and should be minimized as much as practical.

  1. Interactions and chemical transformations of coronene inside and outside carbon nanotubes.

    Science.gov (United States)

    Botka, Bea; Füstös, Melinda E; Tóháti, Hajnalka M; Németh, Katalin; Klupp, Gyöngyi; Szekrényes, Zsolt; Kocsis, Dorina; Utczás, Margita; Székely, Edit; Váczi, Tamás; Tarczay, György; Hackl, Rudi; Chamberlain, Thomas W; Khlobystov, Andrei N; Kamarás, Katalin

    2014-04-09

    By exposing flat and curved carbon surfaces to coronene, a variety of van der Waals hybrid heterostructures are prepared, including coronene encapsulated in carbon nanotubes, and coronene and dicoronylene adsorbed on nanotubes or graphite via π-π interactions. The structure of the final product is determined by the temperature of the experiment and the curvature of the carbon surface. While at temperatures below and close to the sublimation point of coronene, nanotubes with suitable diameters are filled with single coronene molecules, at higher temperatures additional dimerization and oligomerization of coronene occurs on the surface of carbon nanotubes. The fact that dicoronylene and possible higher oligomers are formed at lower temperatures than expected for vapor-phase polymerization indicates the active role of the carbon surface used primarily as template. Removal of adsorbed species from the nanotube surface is of utmost importance for reliable characterization of encapsulated molecules: it is demonstrated that the green fluorescence attributed previously to encapsulated coronene is instead caused by dicoronylene adsorbed on the surface which can be solubilized and removed using surfactants. After removing most of the adsorbed layer, a combination of Raman spectroscopy and transmission electron microscopy was employed to follow the transformation dynamics of coronene molecules inside nanotubes.

  2. Mechano-chemical Interactions in Cardiac Sarcomere Contraction: A Computational Modeling Study

    Science.gov (United States)

    Lumens, Joost; Arts, Theo; Delhaas, Tammo

    2016-01-01

    We developed a model of cardiac sarcomere contraction to study the calcium-tension relationship in cardiac muscle. Calcium mediates cardiac contraction through its interactions with troponin (Tn) and subsequently tropomyosin molecules. Experimental studies have shown that a slight increase in intracellular calcium concentration leads to a rapid increase in sarcomeric tension. Though it is widely accepted that the rapid increase is not possible without the concept of cooperativity, the mechanism is debated. We use the hypothesis that there exists a base level of cooperativity intrinsic to the thin filament that is boosted by mechanical tension, i.e. a high level of mechanical tension in the thin filament impedes the unbinding of calcium from Tn. To test these hypotheses, we developed a computational model in which a set of three parameters and inputs of calcium concentration and sarcomere length result in output tension. Tension as simulated appeared in good agreement with experimentally measured tension. Our results support the hypothesis that high tension in the thin filament impedes Tn deactivation by increasing the energy required to detach calcium from the Tn. Given this hypothesis, the model predicted that the areas with highest tension, i.e. closest to the Z-disk end of the single overlap region, show the largest concentration of active Tn’s. PMID:27716775

  3. Zinc phthalocyanine thin film and chemical analyte interaction studies by density functional theory and vibrational techniques.

    Science.gov (United States)

    Saini, G S S; Singh, Sukhwinder; Kaur, Sarvpreet; Kumar, Ranjan; Sathe, Vasant; Tripathi, S K

    2009-06-03

    Thin films of zinc phthalocyanine have been deposited on KBr and glass substrates by the thermal evaporation method and characterized by the x-ray diffraction, optical, infrared and Raman techniques. The observed x-ray diffraction and infrared absorption spectra of as-deposited thin films suggest the presence of an α crystalline phase. Infrared and Raman spectra of thin films after exposure to vapours of ammonia and methanol have also been recorded. Shifts in the position of some IR and Raman bands in the spectra of exposed films have been observed. Some bands also show changes in their intensity on exposure. Increased charge on the phthalocyanine ring and out-of-plane distortion of the core due to interaction between zinc phthalocyanine and vapour molecules involving the fifth coordination site of the central metal ion may be responsible for the band shifts. Changes in the intensity of bands are interpreted in terms of the lowering of molecular symmetry from D(4h) to C(4v) due to doming of the core. Molecular parameters and Mulliken atomic charges of zinc phthalocyanine and its complexes with methanol and ammonia have been calculated from density functional theory. The binding energy of the complexes have also been calculated. Calculated values of the energy for different complexes suggest that axially coordinated vapour molecules form the most stable complex. Calculated Mulliken atomic charges show net charge transfer from vapour molecules to the phthalocyanine ring for the most stable complex.

  4. Ocean-atmosphere interactions in the emergence of complexity in simple chemical systems.

    Science.gov (United States)

    Griffith, Elizabeth C; Tuck, Adrian F; Vaida, Veronica

    2012-12-18

    elimination of water. The fluctuating exposure of the large, recycling aerosol populations to radiation, pressure, temperature, and humidity over geological time allows complexity to emerge from simple molecular precursors. We propose an approach that connects chemical statistical thermodynamics and the macroscopic world of the planetary ocean and atmosphere.

  5. Interaction of carbon nanotubes and diamonds under hot-filament chemical vapor deposition conditions

    Science.gov (United States)

    Shankar, Nagraj

    A composite of CNTs and diamond can be expected to have unique mechanical, electrical and thermal properties due to the synergetic combination of the excellent properties of these two allotropes of carbon. The composite may find applications in various fields that require a combination of good mechanical, thermal, electrical and optical properties such as, wear-resistant coatings, thermal management of integrated chips (ICs), and field emission devices. This research is devoted to the experimental studies of phase stability of diamond and CNTs under chemical vapor deposition conditions to investigate the possibility of combining these materials to produce a hybrid composite. Growth of the hybrid material is investigated by starting with a pre-existing film of CNTs and subsequently growing diamond on it. The diamond growth phase space is systematically scanned to determine optimal conditions where diamond nucleates on the CNT without destroying it. Various techniques including SEM, TEM, and Micro Raman spectroscopy are used to characterize the hybrid material. A selective window where the diamond directly nucleates on the CNT without destroying the underlying CNT network is identified. Based on the material characterization, a growth mechanism based on etching of CNT at the defective sites to produce sp3 dangling bonds onto which diamond nucleates is proposed. Though a hybrid material is synthesized, the nucleation density of diamond on the CNTs is low and highly non-homogenous. Improvements to the CNT dispersion in the hybrid material are investigated in order to produce a homogenous material with predictable CNT loading fractions and to probe the low nucleation density of diamond on the CNT. The effect of several dispersion techniques and solvents on CNT surface homogeneity is studied using SEM, and a novel, vacuum drying based approach using CNT/dichlorobenzene dispersions is suggested. SEM and Raman analysis of the early stage nucleation are used to develop a

  6. Interaction of Tryptophane and Phenylalanine with Cadmium and Molybdenum Ferrocyanides and Its Implications in Chemical Evolution and Origins of Life.

    Science.gov (United States)

    Tewari, Brij

    2016-07-01

    Insoluble metal hexacyanoferrate(II) complexes could have concentrated biomonomers from dilute prebiotic soup during course of chemical evolution and origin of life or primitive earth. In the light of above hypothesis, adsorption of tryptophane and phenylalanine was studied on cadmium and molybdenum ferrocyanides at neutral pH (7.0 ± 0.01) and at a temperature of 30 ± 1º C. Interaction of amino acids with metal ferrocyanides are found to be maximum at neutral pH. Neutral pH is chosen for the adsorption studies because most of the reactions in biological systems taken place at neutral pH range. Adsorption trend follow Langmuir isotherm model. The Langmuir constants b and Qo were calculated at neutral pH, tryptophane was found to more adsorbed than phenylalanine on both metal ferrocyanides studied. Molybdenum ferrocyanides studied. Molybdenum ferrocyanides was found to have more uptake capacity for both adsorbates than cadmium ferrocyanides. The present study suggests that metal ferrocyanides might have played a role in the stabilization of biomolecules through their surface activity during course of chemical solution and origins of life on primitive earth.

  7. Quantum chemical topology study of the water-platinum(II) interaction.

    Science.gov (United States)

    Bergès, Jacqueline; Fourré, Isabelle; Pilmé, Julien; Kozelka, Jiri

    2013-02-04

    The "inverse hydration" of neutral complexes of Pt(II) by an axial water molecule, whose one OH-bond is oriented toward Pt, has been the subject of recent works, theoretical as well as experimental. To study the influence of the ligands on this non-conventional H-bond, we extend here our previous energy calculations, using the second-order Moeller-Plesset perturbation theory (MP2) method together with the Dolg-Pélissier pseudopotential for platinum, to various neutral complexes including the well-known chemotherapeutic agent "cisplatin". The stabilization energy, depending on the nature and the configuration of platinum ligands, is dominated by the same important dispersive component, for all the investigated complexes. For a further characterization of this particular H-bond, we used the atoms in molecules theory (AIM) and the topological analysis of the electron localization function (ELF). The charge transfer occurring from the complex to the water molecule and the Laplacian of the density at the bond critical point between water and Pt are identified as interesting AIM descriptors of this non-conventional H-bond. Beyond this AIM analysis, we show that the polarization of the ELF bonding O-H basin involved in the non-conventional H-bond is enhanced during the approach of the water molecule to the Pt complexes. When the water medium, treated in an implicit solvation model, is taken into account, the interaction energies become independent on the nature and configuration of platinum ligands. However, the topological descriptors remain qualitatively unchanged.

  8. Glass-water interaction: Effect of high-valence cations on glass structure and chemical durability

    Science.gov (United States)

    Hopf, J.; Kerisit, S. N.; Angeli, F.; Charpentier, T.; Icenhower, J. P.; McGrail, B. P.; Windisch, C. F.; Burton, S. D.; Pierce, E. M.

    2016-05-01

    densities can form. These results illustrate the importance of understanding solid-water/solid-fluid interactions by linking macroscopic reaction kinetics to nanometer scale interfacial processes.

  9. Glass–water interaction: Effect of high-valence cations on glass structure and chemical durability

    Energy Technology Data Exchange (ETDEWEB)

    Hopf, J.; Kerisit, Sebastien N.; Angeli, F.; Charpentier, Thibault M.; Icenhower, Jonathan P.; McGrail, Bernard P.; Windisch, Charles F.; Burton, Sarah D.; Pierce, Eric M.

    2016-05-15

    with higher Si densities can form. These results illustrate the importance of understanding solid–water/solid-fluid interactions by linking macroscopic reaction kinetics to nanometer scale interfacial processes.

  10. Theoretical investigation of the magnetic exchange interactions in copper(II) oxides under chemical and physical pressures.

    Science.gov (United States)

    Rocquefelte, Xavier; Schwarz, Karlheinz; Blaha, Peter

    2012-01-01

    It remains a challenge to understand the unconventional mechanisms that cause high-T(C) superconductivity in cuprate superconductors, high-T(C) multiferroicity in CuO, or low-dimensional magnetism in the spin-Peierls transition compounds such as CuGeO(3). A common feature of all these copper oxide compounds (containing Cu(2+) ions) is the presence of large magnetic superexchange interactions J. It is a general strategy to apply chemical and/or physical pressure in order to tune these exotic properties. Here we show theoretically, for the first time, the impact of physical pressure on J on CuO, for which we predict a strong enhancement of the low-dimensionality of the magnetic interactions and the spin-frustration at high-pressures. Such modifications are expected to strongly influence the multiferroic properties of CuO. We finally demonstrate that PBE0 hybrid DFT calculations provide reliable J values for a wide range of copper(II) oxides compounds, i.e. CuGeO(3), BaCu(2)Si(2)O(7), BaCu(2)Ge(2)O(7), and La(2)CuO(4).

  11. Crystallization of copper(II) sulfate based minerals and MOF from solution: Chemical insights into the supramolecular interactions

    Indian Academy of Sciences (India)

    M Singh; D Kumar; J Thomas; A Ramanan

    2010-09-01

    Crystallization of solids, molecular or non-molecular from solution is a supramolecular reaction. Nucleation of a lattice structure at supersaturation can be conceived to result from a critical nucleus, a high energy intermediate (supramolecular transition state). Conceptualization of a structure for the critical nucleus in terms of aggregation of tectons through non-covalent interactions provides chemical insights into the architecture of a solid. The retrosynthetic analysis of copper-based minerals and materials offers an elegant description for the crystal packing. It addresses the influence of the geometry, functionality and reactivity of copper tecton(s) in directing a specific supramolecular aggregation. The mechanistic approach provides guiding principles to chemists to account for the experimentally crystallized solids and a platform to practice structure-synthesis correlation. Rationalization of the same composition with different atomic arrangements (polymorphs), compositional variation leading to different pseudopolymorphs, degree of hydration (anhydrous to hydrated), water clusters, role of solvent, etc. can all be justified on molecular basis. Also, the method gives predictive components including directions to synthesize new solids. In a nutshell, the paper is an attempt to generalize the crystallization of inorganic solids from solution by recognizing supramolecular interactions between metal tectons and gain insights for designing new MOF.

  12. Electron-electron interactions in the chemical bond: ``1/3” Effect in the bond length of hydrogen molecule

    Indian Academy of Sciences (India)

    P Ganguly

    2001-10-01

    The prominent ``1/3” effect observed in the Hall effect plateaus of twodimensional electron gas (2DEG) systems has been postulated to indicating 1/3 fractional charge quasiparticle excitations arising from electron-electron interactions. Tunneling shot-noise experiments on 2DEF exhibiting fractional quantum Hall effect (FQHE) shows evidence for tunnelling of particles with and /3 charges for a constant band mass. A ``1/3” effect in the hydrogen molecule is seen in as much as its internuclear distance, - = - + +, with |+/-| = 1/3. This is examined in terms of electron-electron interactions involving electron- and hole quasiparticles, (-) and (ℎ+), equivalent to those observed in FQHE shot-noise experiments. The (/) ratio of the (-) and (ℎ+) quasiparticles is kept at 1: -3. Instead of a 2DEG, these particles are treated as being in flat Bohr orbits. A treatment in the language of charge-flux tube composites for the hydrogen atom as well as the hydrogen molecule is attempted. Such treatment gives important insights into changes in chemical potential and bond energy on crossing a phase boundary during the atom-bond transition as well as on models for FQHE itself.

  13. EFFECT OF ORGANIC AND CHEMICAL SOIL FERTILIZERS AND THEIR INTERACTIONS WITH FOLIAR FERTILIZER ON SOME VEGETATIVE GROWTH OF FENUGREEK

    Directory of Open Access Journals (Sweden)

    Ali H. JASIM

    2016-12-01

    Full Text Available The experiment was conducted on the extension experiments farm in Babylon during the growing season 2013 - 2014 to study the effect of 5 soil fertilization treatments [control, 200 kg.ha-1 of NPK (18-18-0 , 4 and 8 t.ha-1 of compost of poultry], and its interaction with 4 treatments of foliar fertilizers [control, spray urea 1 g / liter, spraying humic acid 2 ml.l-1 and spray polimet 2 ml.l-1] on growth and yield of fenugreek. Randomized complete block design (RCBD with three replications was used. Seeds are sown on lines (30 cm apart in 21.10.2013 and the experimental unit contained 6 lines. After a week of germination the seedlings were thinned to 10 cm apart. Soil fertilizers were added as side dressing and the foliar fertilizers were added twice in 15/1 and 01/02/2014. The results showed that chemical fertilizer was superior significantly compared to other treatment in plant height, number of leaves, leaf area and wet and dry weight, while poultry (8 t.ha-1 was superior compared to control in branches number and wet weight. Urea spray was superior in plant height, leaves no. and soft weight. Polimet spray was superior compared to control in branches.plant-1. The interaction between the soil and spraying fertilizers had a significant effect in increasing plant height, branches no., leaves no., leaf area and wet and dry weight.

  14. Intermolecular interaction between rare earth and manganese precursors in metalorganic chemical vapor deposition of perovskite manganite films

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshihiro [Department of Engineering Science, Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa, Osaka 572-8530 (Japan)

    2015-07-15

    The gas-phase reaction mechanism was investigated in liquid delivery metalorganic chemical vapor deposition (MOCVD) of praseodymium and lanthanum manganite films. We studied the gas-phase behavior of praseodymium, lanthanum, and manganese precursors under actual CVD conditions by in situ infrared absorption spectroscopy. The rate of the decrease of the infrared absorbance due to Pr(DPM){sub 3} was almost constant even if Mn(DPM){sub 3} was added, indicating that the intermolecular interaction between Pr and Mn precursors in the gas phase is relatively weak in MOCVD of praseodymium manganite films. On the other hand, the temperature dependence of the infrared absorption indicates that the thermal decomposition of La(DPM){sub 3} was promoted in the presence of Mn(DPM){sub 3}. The significant intermolecular interaction occurs between La and Mn precursors in the gas phase in MOCVD of lanthanum manganite films. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. High-removal selectivity through interaction between polyacrylamide and SiO2 film in poly isolation chemical mechanical planarization.

    Science.gov (United States)

    Kim, Ye-Hwan; Lee, Kee-June; Park, Jea-Gun; Paik, Ungyu

    2009-06-01

    The interaction between polyacrylamide (PAM) and SiO2 film was investigated in order to elucidate the removal polycrystalline silicon (poly Si) to SiO2 selectivity in poly isolation chemical mechanical planarization (CMP). The hydrophilic characteristics of poly Si and SiO2 were analyzed by the X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The surface of SiO2 is more hydrophilic than that of poly Si due to the siloxane (triple bond Si-O-Si triple bond) bonding. The adsorption behavior of PAM on poly Si and SiO2 film was determined by adsorption isotherms and force measurements using atomic force microscopy (AFM). Interaction between siloxane bonding of SiO2 film and the amine group along the backbone of PAM results in the adsorption of PAM on SiO2 film. Consequently, the passivation layer of PAM on the SiO2 film prevented abrasives from approaching the surface of SiO2 film, which led to suppression of the removal rate of SiO2 film from 82 to 12 A/min in poly isolation CMP process.

  16. Hydrological budget of Lake Chad: assessment of lake-groundwater interaction by coupling Bayesian approach and chemical budget

    Science.gov (United States)

    Bouchez, Camille; Goncalves, Julio; Deschamps, Pierre; Seidel, Jean-Luc; Doumnang, Jean-Claude; Sylvestre, Florence

    2014-05-01

    Estimation of lake-groundwater interactions is a crucial step to constrain water balance of lacustrine and aquifer systems. Located in the Sahel, the Lake Chad is at the center of an endorheic basin of 2,5.106 km2. One of the most remarkable features of this terminal lake is that, despite the semi-arid context and high evaporation rates of the area, its waters are fresh. It is proposed in the literature that the solutes are evacuated in the underlying quaternary aquifer bearing witness to the importance of surface water and groundwater exchanges for the chemical regulation of the lake. The water balance of this system is still not fully understood. The respective roles of evaporation versus infiltration into the quaternary aquifer are particularly under constrained. To assess lake-groundwater flows, we used the previous conceptual hydrological model of the lake Chad proposed by Bader et al. (Hydrological Sciences Journal, 2011). This model involves six parameters including infiltration rate. A probabilistic inversion of parameters, based on an exploration of the parameters space through a Metropolis algorithm (a Monte Carlo Markov Chain method), allows the construction of an a posteriori Probability Density Function of each parameter yielding to the best fits between observed lake levels and simulated. Then, a chemical budget of a conservative element, such as chloride, is introduced in the water balance model using the optimal parameters resulting from the Bayesian inverse approach. The model simulates lake level and chloride concentration variations of lake Chad from 1956 up to 2008. Simulated lake levels are in overall agreement with the observations, with a Nash-Sutcliffe efficiency coefficient above 0.94 for all sets of parameters retained. The infiltration value, obtained by such probabilistic inversion approach, accounts for 120±20 mm/yr, representing 5% of the total outputs of the lake. However, simulated chloride concentrations are overestimated in

  17. Turning-off Signaling by Siglecs, Selectins and Galectins: Chemical Inhibition of Glycan-dependent Interactions in Cancer

    Directory of Open Access Journals (Sweden)

    Alejandro Javier Cagnoni

    2016-05-01

    Full Text Available Aberrant glycosylation, a common feature associated with malignancy, has been implicated in important events during cancer progression. Our understanding of the role of glycans in cancer has grown exponentially in the last few years, concurrent with important advances in glycomics and glycoproteomic technologies, paving the way for the validation of a number of glycan structures as potential glycobiomarkers. However, the molecular bases underlying cancer-associated glycan modifications are still far from understood. Glycans exhibit a natural heterogeneity, crucial for their diverse functional roles as specific carriers of biologically-relevant information. This information is decoded by families of proteins named lectins, including siglecs, C-type lectin receptors (CLRs and galectins. Siglecs, sialic-acid binding transmembrane lectins, are primarily expressed on the surface of immune cells and differentially control innate and adaptive immune responses. Among CLRs, selectins are a family of cell adhesion molecules that mediate interactions between cancer cells and platelets, leukocytes and endothelial cells, thus facilitating tumor cell invasion and metastasis. Galectins, a family of soluble proteins that bind β-galactoside-containing glycans, have been implicated in diverse events associated with cancer biology such as apoptosis, homotypic cell aggregation, angiogenesis, cell migration and tumor-immune escape. Consequently, individual members of these lectin families have become promising targets for the design of novel anticancer therapies. During the past decade a number of inhibitors of lectin-glycan interactions have been developed including small-molecule inhibitors, multivalent saccharide ligands, and more recently peptides and peptidomimetics have offered alternatives for tackling tumor progression. In this article, we review the current status of the discovery and development of chemical lectin inhibitors and discuss novel strategies

  18. New insights into the interactions between cork chemical components and pesticides. The contribution of π-π interactions, hydrogen bonding and hydrophobic effect.

    Science.gov (United States)

    Olivella, M À; Bazzicalupi, C; Bianchi, A; Fiol, N; Villaescusa, I

    2015-01-01

    The role of chemical components of cork in the sorption of several pesticides has been investigated. For this purpose raw cork and three cork extracted fractions (i.e. cork free of aliphatic extractives, cork free of all extractives and cork free of all extractives and suberin) were used as sorbent of three ionic pesticides (propazine, 2,4-dichlorophenoxy acetic acid (2,4-D) and alachlor) and five non-ionic pesticides (chlorpyrifos, isoproturon, metamitron, methomyl and oxamyl) with a logKow within the range -0.47 to 4.92. The effect of cations on the ionic pesticides, propazine and 2,4-D sorption was also analyzed. Results indicated that the highest yields were obtained for chlorpyrifos and alachlor sorption onto raw cork (>55%). After removal of aliphatic extractives sorption of all pesticides increased that ranged from 3% for propazine to 31% for alachlor. In contrast, removal of phenolic extractives caused a sorption decrease. Low sorption yields were obtained for hydrophobic pesticides such as metamitron, oxamyl and methomyl (cork fractions and extremely low when using raw cork (cork toward aromatic pesticides. Results presented in this paper gain insights into the cork affinities for pesticides and the interactions involved in the sorption process and also enables to envisage sorption affinity of cork for other organic pollutants.

  19. Compatibility study between U-UO2 cermet fuel and T91 cladding

    Science.gov (United States)

    Mishra, Sudhir; Kaity, Santu; Khan, K. B.; Sengupta, Pranesh; Dey, G. K.

    2016-12-01

    Cermet is a new fuel concept for the fast reactor system and is ideally designed to combine beneficial properties of both ceramic and metal. In order to understand fuel clad chemical compatibility, diffusion couples were prepared with U-UO2 cermet fuel and T91 cladding material. These diffusion couples were annealed at 923-1073 K for 1000 h and 1223 K for 50 h, subsequently their microstructures were examined using scanning electron microscope (SEM), X-ray energy dispersive spectroscope (EDS) and electron probe microanalyser (EPMA). It was observed that the interaction between the fuel and constituents of T91 clad was limited to a very small region up to the temperature 993 K and discrete U6(Fe,Cr) and U(Fe,Cr)2 intermetallic phases developed. Eutectic microstructure was observed in the reaction zone at 1223 K. The activation energy for reaction at the fuel clad interface was determined.

  20. Exploring non-covalent interactions in guanine- and xanthine-based model DNA quadruplex structures: a comprehensive quantum chemical approach.

    Science.gov (United States)

    Yurenko, Yevgen P; Novotný, Jan; Sklenář, Vladimir; Marek, Radek

    2014-02-07

    The study aimed to cast light on the structure and internal energetics of guanine- and xanthine-based model DNA quadruplexes and the physico-chemical nature of the non-covalent interactions involved. Several independent approaches were used for this purpose: DFT-D3 calculations, Quantum Theory of Atoms in Molecules, Natural Bond Orbital Analysis, Energy Decomposition Analysis, Compliance Constant Theory, and Non-Covalent Interaction Analysis. The results point to an excellent degree of structural and energetic compatibility between the two types of model quadruplexes. This fact stems from both the structural features (close values of van der Waals volumes, pore radii, geometrical parameters of the H-bonds) and the energetic characteristics (comparable values of the energies of formation). It was established that hydrogen bonding makes the greatest (∼50%) contribution to the internal stability of the DNA quadruplexes, whereas the aromatic base stacking and ion coordination terms are commensurable and account for the rest. Energy decomposition analysis performed for guanine (Gua) and xanthine (Xan) quartets B4 and higher-order structures consisting of two or three stacked quartets indicates that whereas Gua structures benefit from a high degree of H-bond cooperativity, Xan models are characterized by a more favorable and cooperative π-π stacking. The results of electron density topological analysis show that Na(+)/K(+) ion coordination deeply affects the network of non-covalent interactions in Gua models due to the change in the twist angle between the stacked tetrads. For Xan models, ion coordination makes tetrads in stacks more planar without changing the twist angle. Therefore, the presence of the ion seems to be essential for the formation of planar stacks in Xan-based DNA quadruplexes. Detailed study of the nature of ion-base coordination suggests that this interaction has a partially covalent character and cannot be considered as purely electrostatic

  1. Spectral Induced Polarization monitoring of the groundwater physico-chemical parameters daily variations for stream-groundwater interactions

    Science.gov (United States)

    Jougnot, Damien; Camerlynck, Christian; Robain, Henri; Tallec, Gaëlle; Ribolzi, Olivier; Gaillardet, Jérôme

    2017-04-01

    performed. Relating the daily fluctuations of the groundwater complex conductivity and the river physico-chemical parameters could therefore establish a new proxy to characterize stream-groundwater interactions. In parallel to the field measurements, laboratory experiments have been conducted on soil samples from the two sites. These measurements provide a better understanding of the complex conductivity signature of the samples submitted to saturation and pore water physico-chemical changes. This work is in progress but the first results already show that the method has a real interest for the monitoring of daily variations of the physico-chemistry properties of the groundwater and their relations to those of the stream.

  2. Quantum-chemical study of interactions of trans-resveratrol with guanine-thymine dinucleotide and DNA-nucleobases.

    Science.gov (United States)

    Mikulski, Damian; Szeląg, Małgorzata; Molski, Marcin

    2011-12-01

    Trans-resveratrol, a natural phytoalexin present in red wine and grapes, has gained considerable attention because of its antiproliferative, chemopreventive and proapoptotic activity against human cancer cells. The accurate quantum-chemical computations based on the density functional theory (DFT) and ab initio second-order Møller-Plesset perturbation method (MP2) have been performed for the first time to study interactions of trans-resveratrol with guanine-thymine dinucleotide and DNA-derived nitrogenous bases: adenine, guanine, cytosine and thymine in vacuum and water medium. This compound is found to show high affinity to nitrogenous bases and guanine-thymine dinucleotide. The electrostatic interactions from intermolecular hydrogen bonding increase the stability of complexes studied. In particular, significantly strong hydrogen bonds between 4'-H atom of trans-resveratrol and imidazole nitrogen as well as carbonyl oxygen atoms of nucleobases studied stabilize these systems. The stabilization energies computed reveal that the negatively charged trans-resveratrol-dinucleotide complex is more energetically stable in water medium than in vacuum. MP2 method gives more reliable and significantly high values of stabilization energy of trans-resveratrol-dinucleotide, trans-resveratrol-guanine and trans-resveratrol-thymine complexes than B3LYP exchange-correlation functional because it takes into account London dispersion energy. According to the results, in the presence of trans-resveratrol the 3'-5' phosphodiester bond in dinucleotide can be cleaved and the proton from 4'-OH group of trans-resveratrol migrates to the 3'-O atom of dinucleotide. It is concluded that trans-resveratrol is able to break the DNA strand. Hence, the findings obtained help understand antiproliferative and anticancer properties of this polyphenol.

  3. Role of physical and chemical interactions in the antibacterial behavior of ZnO nanoparticles against E. coli.

    Science.gov (United States)

    Jiang, Yunhong; Zhang, Lingling; Wen, Dongsheng; Ding, Yulong

    2016-12-01

    Zinc oxide (ZnO) nanoparticles (NPs) exhibit antibacterial activity against both Gram-positive and Gram-negative bacteria. However, the antimicrobial mechanism of ZnO NPs remains unclear. In this study, we investigated the interactions among ZnO NPs, released chemicals (Zn(2+) and Reactive Oxygen Species, ROS) and Escherichia coli (E. coli) cells. ZnO NPs without contacting with bacterial cells showed strong antibacterial effect. The results of the leakage of intracellular K(+) and integrity of carboxyfluoresce in-filled liposomes showed that ZnO NPs have antimicrobial activity against E. coli by non-specifically disrupting E. coli membranes. Traces of zinc ions (1.25mg/L) and hydrogen peroxide (from 1.25 to 4.5μM/L) were detected in ZnO NPs suspensions, but was insufficient to cause the antibacterial effect. However, the addition of radical scavengers suppressed the bactericidal effect of ZnO coated films against E. coli, potentially implicating ROS generation, especially hydroxyl radicals, in the antibacterial ability of ZnO NPs.

  4. Chemical interactions with pyramidal neurons in layer 5 of the cerebral cortex: control of pain and anxiety.

    Science.gov (United States)

    Adams, J D

    2009-01-01

    Pyramidal neurons in layer 5 of the cerebral cortex are involved in learning and memory and have complex connections with other neurons through a very large array of dendrites. These dendrites can switch between long term depression and long term potentiation depending on global summation of various inputs. The plasticity of the input into pyramidal neurons makes the neuronal output variable. Many interneurons in the cerebral cortex and distant neurons in other brain regions are involved in providing input to pyramidal neurons. All of these neurons and interneurons have neurotransmitters that act through receptors to provide input to pyramidal neurons. Serotonin is one of the important neurotransmitters involved with pyramidal neurons and has been implicated in psychosis, psychedelic states and what are called sacred dreams. This review will discuss the various chemicals and receptors that are important with pyramidal neurons including opioids, nicotine, scopolamine, psilocybin, LSD, mescaline, ergot alkaloids, salvinorin A, ergine and other compounds that interact with opioid, nicotinic, muscarinic and serotonergic receptors. The natural compounds provide clues to structure activity relationships with the receptors. It has been postulated that each receptor in the body has a natural agonist and antagonist, in addition to the normal neurotransmitters. It is common for natural antagonists and agonists to be peptides. Various possible peptide structures will be proposed for natural antagonists and agonists at each receptor. Natural antagonists and agonists may provide new ways to explore the functions of pyramidal neurons in normal health and pain management.

  5. Quorum Sensing and Quorum Quenching in the Phycosphere of Phytoplankton: a Case of Chemical Interactions in Ecology.

    Science.gov (United States)

    Rolland, Jean Luc; Stien, Didier; Sanchez-Ferandin, Sophie; Lami, Raphaël

    2016-12-01

    The interactions between bacteria and phytoplankton regulate many important biogeochemical reactions in the marine environment, including those in the global carbon, nitrogen, and sulfur cycles. At the microscopic level, it is now well established that important consortia of bacteria colonize the phycosphere, the immediate environment of phytoplankton cells. In this microscale environment, abundant bacterial cells are organized in a structured biofilm, and exchange information through the diffusion of small molecules called semiochemicals. Among these processes, quorum sensing plays a particular role as, when a sufficient abundance of cells is reached, it allows bacteria to coordinate their gene expression and physiology at the population level. In contrast, quorum quenching mechanisms are employed by many different types of microorganisms that limit the coordination of antagonistic bacteria. This review synthesizes quorum sensing and quorum quenching mechanisms evidenced to date in the phycosphere, emphasizing the implications that these signaling systems have for the regulation of bacterial communities and their activities. The diversity of chemical compounds involved in these processes is examined. We further review the bacterial functions regulated in the phycosphere by quorum sensing, which include biofilm formation, nutrient acquisition, and emission of algaecides. We also discuss quorum quenching compounds as antagonists of quorum sensing, their function in the phycosphere, and their potential biotechnological applications. Overall, the current state of the art demonstrates that quorum sensing and quorum quenching regulate a balance between a symbiotic and a parasitic way of life between bacteria and their phytoplankton host.

  6. HM{sup +}–RG complexes (M = group 2 metal; RG = rare gas): Physical vs. chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Joe P.; Dodson, Hannah; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Breckenridge, W. H. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)

    2015-04-21

    Previous work on the HM{sup +}–He complexes (M = Be–Ra) has been extended to the cases of the heavier rare gas atoms, HM{sup +}–RG (RG = Ne–Rn). Optimized geometries and harmonic vibrational frequencies have been calculated using MP2 theory and quadruple-ζ quality basis sets. Dissociation energies for the loss of the rare gas atom have been calculated at these optimized geometries using coupled cluster with single and double excitations and perturbative triples, CCSD(T)theory, extrapolating interaction energies to the basis set limit. Comparisons are made between the present data and the previously obtained helium results, as well as to those of the bare HM{sup +} molecules; furthermore, comparisons are made to the related M{sup +}–RG and M{sup 2+}–RG complexes. Partial atomic charge analyses have also been undertaken, and these used to test a simple charge-induced dipole model. Molecular orbital diagrams are presented together with contour plots of the natural orbitals from the quadratic configuration with single and double excitations (QCISD) density. The conclusion is that the majority of these complexes are physically bound, with very little sharing of electron density; however, for M = Be, and to a lesser extent M = Mg, some evidence for chemical effects is seen in HM{sup +}–RG complexes involving RG atoms with the higher atomic numbers.

  7. Characterization of the Raptor/4E-BP1 interaction by chemical cross-linking coupled with mass spectrometry analysis.

    Science.gov (United States)

    Coffman, Kimberly; Yang, Bing; Lu, Jie; Tetlow, Ashley L; Pelliccio, Emelia; Lu, Shan; Guo, Da-Chuan; Tang, Chun; Dong, Meng-Qiu; Tamanoi, Fuyuhiko

    2014-02-21

    mTORC1 plays critical roles in the regulation of protein synthesis, growth, and proliferation in response to nutrients, growth factors, and energy conditions. One of the substrates of mTORC1 is 4E-BP1, whose phosphorylation by mTORC1 reverses its inhibitory action on eIF4E, resulting in the promotion of protein synthesis. Raptor in mTOR complex 1 is believed to recruit 4E-BP1, facilitating phosphorylation of 4E-BP1 by the kinase mTOR. We applied chemical cross-linking coupled with mass spectrometry analysis to gain insight into interactions between mTORC1 and 4E-BP1. Using the cross-linking reagent bis[sulfosuccinimidyl] suberate, we showed that Raptor can be cross-linked with 4E-BP1. Mass spectrometric analysis of cross-linked Raptor-4E-BP1 led to the identification of several cross-linked peptide pairs. Compilation of these peptides revealed that the most N-terminal Raptor N-terminal conserved domain (in particular residues from 89 to 180) of Raptor is the major site of interaction with 4E-BP1. On 4E-BP1, we found that cross-links with Raptor were clustered in the central region (amino acid residues 56-72) we call RCR (Raptor cross-linking region). Intramolecular cross-links of Raptor suggest the presence of two structured regions of Raptor: one in the N-terminal region and the other in the C-terminal region. In support of the idea that the Raptor N-terminal conserved domain and the 4E-BP1 central region are closely located, we found that peptides that encompass the RCR of 4E-BP1 inhibit cross-linking and interaction of 4E-BP1 with Raptor. Furthermore, mutations of residues in the RCR decrease the ability of 4E-BP1 to serve as a substrate for mTORC1 in vitro and in vivo.

  8. Relationship of Non-Structural Forms of Social Interaction with Problems of Social and Psychological Adaptation of Students Prone to Chemical Addictions

    Science.gov (United States)

    Gilemkhanova, Elvira N.

    2016-01-01

    The changes in contemporary social and cultural environment determine the necessity to increase the efficiency of adaptive mechanisms, especially for those categories of people who are subject to social risks. One of those categories is students prone to chemical addictions. To study the relationship of forms of social interaction with problems of…

  9. Effect of chemical carcinogens and partial hepatectomy on in vivo ( sup 35 S)methionine interaction with rat liver tRNA

    Energy Technology Data Exchange (ETDEWEB)

    Kanduc, D.; Aresta, A.; Rossiello, M.R.; Ranieri, T.; Quagliariello, E. (Universita di Bari (Italy))

    1989-09-29

    The effect of carcinogens given by a single or multiple injections on the extent of ({sup 35}S)methionine interaction with hepatic tRNA was studied in normal and partially hepatectomized rats. Either partial hepatectomy or administration of ethionine (100 or 330 mg/kg body weight) and dimethylnitrosamine (120 mg/kg body weight) by multiple i.p. injections inhibited the ({sup 35}S)methionine-tRNA interaction, while administration of hepatocarcinogenic chemicals plus PH resulted rather in a stimulation. Methylnitrosourea enhanced the extent of interaction when administered in a single dose (100 mg per kg body weight) 18 h after partial hepatectomy.

  10. Dislocation dynamics simulations of interactions between gliding dislocations and radiation induced prismatic loops in zirconium

    Science.gov (United States)

    Drouet, Julie; Dupuy, Laurent; Onimus, Fabien; Mompiou, Frédéric; Perusin, Simon; Ambard, Antoine

    2014-06-01

    The mechanical behavior of Pressurized Water Reactor fuel cladding tubes made of zirconium alloys is strongly affected by neutron irradiation due to the high density of radiation induced dislocation loops. In order to investigate the interaction mechanisms between gliding dislocations and loops in zirconium, a new nodal dislocation dynamics code, adapted to Hexagonal Close Packed metals, has been used. Various configurations have been systematically computed considering different glide planes, basal or prismatic, and different characters, edge or screw, for gliding dislocations with -type Burgers vectors. Simulations show various interaction mechanisms such as (i) absorption of a loop on an edge dislocation leading to the formation of a double super-jog, (ii) creation of a helical turn, on a screw dislocation, that acts as a strong pinning point or (iii) sweeping of a loop by a gliding dislocation. It is shown that the clearing of loops is more favorable when the dislocation glides in the basal plane than in the prismatic plane explaining the easy dislocation channeling in the basal plane observed after neutron irradiation by transmission electron microscopy.

  11. Chemical Interactions of Uranium in Water, Sediments, and Plants Along a Watershed Adjacent to the Abandoned Jackpile Mine

    Science.gov (United States)

    Blake, J.; De Vore, C. L.; Avasarala, S.; Ali, A.; Roldan, C.; Bowers, F.; Spilde, M.; Artyushkova, K.; Cerrato, J.

    2015-12-01

    The chemical interactions, mobility, and plant uptake of uranium (U) near abandoned mine wastes was investigated along the Rio Paguate, adjacent to the Jackpile Mine, located in Laguna Pueblo, New Mexico. Elevated U concentrations in surface water adjacent to mine waste range from 30 to 710 μg/L seasonally and decrease to 5.77 to 10.0 μg/L at a wetland 4.5 kilometers downstream of the mine. Although U concentrations in stream water are elevated, aqua regia acid digestions performed on co-located stream bed and stream bank sediments reveal that there is limited U accumulation on sediments along the reach between the mine and wetland, with most sediment concentrations being near the 3 mg/kg crustal average. However, U concentrations in sediments in the wetland are 4 times the background concentrations in the area. Individual results from salt cedar roots, stems, and leaves collected along the river transect show higher U concentrations in the roots adjacent to the mine waste (20 and 55 mg/kg) and lower in the stems and leaves. Translocation values calculated below 1 are evident in many of the plant samples, suggesting that U root to shoot translocation is minimal and U is accumulating in the roots. Concentrations of U in salt cedar roots from downstream of the mine waste decrease to 15 mg/kg. X-ray photoelectron spectroscopy analysis on sediment samples adjacent to the mine waste show a 75:25% ratio of Fe(III) to Fe(II), which can have an effect on adsorption properties. Electron microprobe results suggest that the ore in this area is present as a uranium-phosphate phase. Our results suggest that dilution, uptake by plants, and U sorption to wetland sediments are the dominant factors that help to decrease the U concentrations downstream of the mine.

  12. One-step method for generating PEG-like plasma polymer gradients: chemical characterization and analysis of protein interactions.

    Science.gov (United States)

    Menzies, Donna J; Cowie, Bruce; Fong, Celesta; Forsythe, John S; Gengenbach, Thomas R; McLean, Keith M; Puskar, Ljiljana; Textor, Marcus; Thomsen, Lars; Tobin, Mark; Muir, Benjamin W

    2010-09-07

    In this work we report a one-step method for the fabrication of poly(ethylene glycol) PEG-like chemical gradients, which were deposited via continuous wave radio frequency glow discharge plasma polymerization of diethylene glycol dimethyl ether (DG). A knife edge top electrode was used to produce the gradient coatings at plasma load powers of 5 and 30 W. The chemistry across the gradients was analyzed using a number of complementary techniques including spatially resolved synchrotron source grazing incidence FTIR microspectroscopy, X-ray photoelectron spectroscopy (XPS) and synchrotron source near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Gradients deposited at lower load power retained a higher degree of monomer like functionality as did the central region directly underneath the knife edge electrode of each gradient film. Surface derivatization experiments were employed to investigate the concentration of residual ether units in the films. In addition, surface derivatization was used to investigate the reactivity of the gradient films toward primary amine groups in a graft copolymer of poly (L-lysine) and poly(ethylene glycol) (PLL-g-PEG copolymer) which was correlated to residual aldehyde, ketone and carboxylic acid functionalities within the films. The protein adsorption characteristics of the gradients were analyzed using three proteins of varying size and charge. Protein adsorption varied and was dependent on the chemistry and the physical properties (such as size and charge) of the proteins. A correlation between the concentration of ether functionality and the protein fouling characteristics along the gradient films was observed. The gradient coating technique developed in this work allows for the efficient and high-throughput study of biomaterial gradient coating interactions.

  13. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...

  14. Chemical interaction at the buried silicon/zinc oxide thin-film solar cell interface as revealed by hard X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, M., E-mail: mark.wimmer@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Gerlach, D.; Wilks, R.G.; Scherf, S.; Félix, R. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Lupulescu, C. [Institute for Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Ruske, F.; Schondelmaier, G.; Lips, K. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Hüpkes, J. [Institute for Energy Research, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Gorgoi, M. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Eberhardt, W. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institute for Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Rech, B. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Bär, M., E-mail: marcus.baer@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus, Konrad-Wachsmann-Allee 1, 03046 Cottbus (Germany)

    2013-10-15

    Highlights: •We used HAXPES to identify chemical interactions at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. •The results indicate a diffusion of zinc and aluminum into the silicon upon annealing procedures which are part of the solar cell processing. •The contamination of the silicon may be detrimental for the solar cell performance. -- Abstract: Hard X-ray photoelectron spectroscopy (HAXPES) is used to identify chemical interactions (such as elemental redistribution) at the buried silicon/aluminum-doped zinc oxide thin-film solar cell interface. Expanding our study of the interfacial oxidation of silicon upon its solid-phase crystallization (SPC), in which we found zinc oxide to be the source of oxygen, in this investigation we address chemical interaction processes involving zinc and aluminum. In particular, we observe an increase of zinc- and aluminum-related HAXPES signals after SPC of the deposited amorphous silicon thin films. Quantitative analysis suggests an elemental redistribution in the proximity of the silicon/aluminum-doped zinc oxide interface – more pronounced for aluminum than for zinc – as explanation. Based on these insights the complex chemical interface structure is discussed.

  15. Scoping assessments of ATF impact on late-stage accident progression including molten core-concrete interaction

    Science.gov (United States)

    Farmer, M. T.; Leibowitz, L.; Terrani, K. A.; Robb, K. R.

    2014-05-01

    Simple scoping models that can be used to evaluate ATF performance under severe accident conditions have been developed. The methodology provides a fundamental technical basis (a.k.a. metric) based on the thermodynamic boundary for evaluating performance relative to that of traditional Zr-based claddings. The initial focus in this study was on UO2 fuel with the advanced claddings 310 SS, D9, FeCrAl, and SiC. The evaluation considered only energy release with concurrent combustible gas production from fuel-cladding-coolant interactions and, separately, molten core-concrete interactions at high temperatures. Other important phenomenological effects that can influence the rate and extent of cladding decomposition (e.g., eutectic interactions, degradation of other core constituents) were not addressed. For the cladding types addressed, potential combustible gas production under both in-vessel and ex-vessel conditions was similar to that for Zr. However, exothermic energy release from cladding oxidation was substantially less for iron-based alloys (by at least a factor of 4), and modestly less (by ∼20%) for SiC. Data on SiC-clad UO2 fuel performance under severe accident conditions are sparse in the literature; thus, assumptions on the nature of the cladding decomposition process were made in order to perform this initial screening evaluation. Experimental data for this system under severe accident conditions is needed for a proper evaluation and comparison to iron-based claddings.

  16. Investigation of the Chemical Interface in the Soybean-Aphid and Rice-Bacteria Interactions Using MALDI-Mass Spectrometry Imaging.

    Science.gov (United States)

    Klein, Adam T; Yagnik, Gargey B; Hohenstein, Jessica D; Ji, Zhiyuan; Zi, Jiachen; Reichert, Malinda D; MacIntosh, Gustavo C; Yang, Bing; Peters, Reuben J; Vela, Javier; Lee, Young Jin

    2015-05-19

    Mass spectrometry imaging (MSI) is an emerging technology for high-resolution plant biology. It has been utilized to study plant-pest interactions, but limited to the surface interfaces. Here we expand the technology to explore the chemical interactions occurring inside the plant tissues. Two sample preparation methods, imprinting and fracturing, were developed and applied, for the first time, to visualize internal metabolites of leaves in matrix-assisted laser desorption ionization (MALDI)-MSI. This is also the first time nanoparticle-based ionization was implemented to ionize diterpenoid phytochemicals that were difficult to analyze with traditional organic matrices. The interactions between rice-bacterium and soybean-aphid were investigated as two model systems to demonstrate the capability of high-resolution MSI based on MALDI. Localized molecular information on various plant- or pest-derived chemicals provided valuable insight for the molecular processes occurring during the plant-pest interactions. Specifically, salicylic acid and isoflavone based resistance was visualized in the soybean-aphid system and antibiotic diterpenoids in rice-bacterium interactions.

  17. Final Report: Development of a Chemical Model to Predict the Interactions between Supercritical CO2, Fluid and Rock in EGS Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, Brian J. [University of Utah; Pan, Feng [University of Utah

    2014-09-24

    This report summarizes development of a coupled-process reservoir model for simulating enhanced geothermal systems (EGS) that utilize supercritical carbon dioxide as a working fluid. Specifically, the project team developed an advanced chemical kinetic model for evaluating important processes in EGS reservoirs, such as mineral precipitation and dissolution at elevated temperature and pressure, and for evaluating potential impacts on EGS surface facilities by related chemical processes. We assembled a new database for better-calibrated simulation of water/brine/ rock/CO2 interactions in EGS reservoirs. This database utilizes existing kinetic and other chemical data, and we updated those data to reflect corrections for elevated temperature and pressure conditions of EGS reservoirs.

  18. Interactions

    DEFF Research Database (Denmark)

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists...... such as Lorentz and Einstein as well as mathematicians such as Poincare, Minkowski, Hilbert and Weyl contributed to this development. They created the new physical theories and the mathematical disciplines that play such paramount roles in their mathematical formulations. These physicists and mathematicians were...

  19. Preparation and characterization of chemical gradient surfaces and their application for the study of cellular interaction phenomena

    NARCIS (Netherlands)

    Ruardy, TG; Schakenraad, JM; vanderMei, HC; Busscher, HJ

    1997-01-01

    Chemical gradient surfaces are surfaces with a gradually changing chemistry along their length which is responsible for a position bound variation in physical properties, most notably, the wettability. In this review, methods to prepare (palladium deposition, diffusion technique, density gradient

  20. Steam chemistry - interaction of chemical species with water, steam, and materials during evaporation, superheating, and condensation. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    Topics of this proceedings are: steam chemistry, supercritical water, effects of chemicals in steam (acetic acid, formic acid, phosphoric acid or other impurities); solubility and deposition, condensation processes and effect of impurities; nucleation; gas-liquid interfaces; steam treatment. (SR)

  1. Monitoring the Interaction of Two Heterocyclic Compounds on Carbon Steel by Electrochemical Polarization, Noise, and Quantum Chemical Studies

    Directory of Open Access Journals (Sweden)

    Vinod P. Raphael

    2016-01-01

    Full Text Available A heterocyclic phenylhydrazone 2-[(E-(2-phenylhydrazinylidenemethyl]pyridine (P2APH and its reduced form 2-[(2-phenylhydrazinylmethyl]pyridine (RP2APH were synthesized, characterized, and subjected to corrosion inhibition investigation on carbon steel (CS in 1 M HCl using gravimetric, polarization, electrochemical noise, quantum chemical, and surface studies. P2APH showed more inhibition capacity than RP2PPH. But RP2PPH was very stable in acid medium and showed pronounced corrosion inhibition efficacy for days. Energy of HOMO and LUMO, their difference, number of electrons transferred, electronegativity, chemical hardness, and so forth were evaluated by quantum chemical studies. Agreeable correlation was observed between the results of quantum chemical calculations and other corrosion monitoring techniques.

  2. Prioritization of Contaminants of Emerging Concern in Wastewater Treatment Plant Discharges using Chemical:Gene Interactions in Caged Fish.

    Data.gov (United States)

    U.S. Environmental Protection Agency — We examined whether contaminants present in surface waters could be prioritized for further assessment by linking the presence of specific chemicals to gene...

  3. Forming chemical composition of surface waters in the Arctic as "water - rock" interaction. Case study of lake Inari and river Paz

    Science.gov (United States)

    Mazukhina, Svetlana; Sandimirov, Sergey; Pozhilenko, Vladimir; Ivanov, Stanislav; Maksimova, Viktoriia

    2017-04-01

    Due to the depletion of fresh water supplies and the deterioration of their quality as a result of anthropogenic impact on the Arctic ecosystems, the research questions of forming surface and ground waters, their interactions with the rocks, development of the foundations for their rational use and protection are of great fundamental and practical importance. The aim of the work is to evaluate the influence of the chemical composition of rocks of the northern part of the Fennoscandian (Baltic) shield on forming surface waters chemical composition (Lake Inari, river Paz) using physical-chemical modeling (Chudnenko, 2010, Selector software package). River Paz (Paatsjoki) is the largest river in North Fennoscandia and flows through the territory of three countries - Finland, Russia and Norway. It originates from Lake Inari, which a large number of streams and rivers flow into, coming from the mountain range of the northern Finland (Maanselkä hill). Within the catchment of inflows feeding the lake Inari and river Paz in its upper flow there are mainly diverse early Precambrian metamorphic and intrusive rocks of the Lapland granulite belt and its framing, and to a lesser extent - various gneisses and migmatites with relicts of amphibolites, granitic gneisses, plagioclase and plagio- and plagiomicrocline granites, and quartz diorites of Inari terrane (Meriläinen, 1976, fig 1; Hörmann et al, 1980, fig 1; Geologicalmap, 2001). Basing on the techniques developed earlier (Mazukhina, 2012), and the data of monitoring of the chemical composition of surface waters and investigation of the chemical composition of the rocks, physical-chemical modeling (FCM) (Selector software package) was carried out. FCM includes 34 independent components (Al-B-Br-Ar-He-Ne-C-Ca-Cl-F-Fe-K-Mg-Mn-N-Na-P-S-Si-Sr-Cu-Zn-Ni-Pb-V-Ba-Co-Cr-Hg-As-Cd-H-O-e), 996 dependent components, of them 369 in aqueous solution, 76 in the gas phase, 111 liquid hydrocarbons, and 440 solid phases, organic and mineral

  4. Feasibility study of fuel cladding performance for application in ultra-long cycle fast reactor

    Science.gov (United States)

    Jung, Ju Ang; Kim, Seung Hyun; Shin, Sang Hun; Bang, In Cheol; Kim, Ji Hyun

    2013-09-01

    As a part of the research and development activities for long-life core sodium-cooled fast reactors, the cladding performance of the ultra-long cycle fast reactor (UCFR) is evaluated with two design power levels (1000 MWe and 100 MWe) and cladding peak temperatures (873 K and 923 K). The key design concept of the UCFR is that it is non-refueling during its 30-60 years of operation. This concept may require a maximum peak cladding temperature of 923 K and a cladding radiation damage of over 200 dpa (displacements per atom). Therefore, for the design of the UCFR, deformation due to thermal creep, irradiation creep, and swelling must be taken into consideration through quantitative evaluations. As candidate cladding materials for use in UCFRs, ferritic-martensitic (FM) steels, oxide dispersion strengthened (ODS) steels, and SiC-based composite materials are studied using deformation behavior modeling for a feasibility evaluation. The results of this study indicate that SiC is a potential UCFR cladding material, with the exception of irradiation creep due to high neutron fluence stemming from its long operating time of about 30-60 years.

  5. Investigation and basic evaluation for ultra-high burnup fuel cladding material

    Energy Technology Data Exchange (ETDEWEB)

    Ioka, Ikuo; Nagase, Fumihisa; Futakawa, Masatoshi; Kiuchi, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Suga, Masataka [Kokan Keisoku Co., Kawasaki, Kanagawa (Japan)

    2001-03-01

    In ultra-high burnup of the power reactor, it is an essential problem to develop the cladding with excellent durability. First, development history and approach of the safety assessment of Zircaloy for the high burnup fuel were summarized in the report. Second, the basic evaluation and investigation were carried out on the material with high practicability in order to select the candidate materials for the ultra-high burnup fuel. In addition, the basic research on modification technology of the cladding surface was carried out from the viewpoint of the addition of safety margin as a cladding. From the development history of the zirconium alloy including the Zircaloy, it is hard to estimate the results of in-pile test from those of the conventional corrosion test (out-pile test). Therefore, the development of the new testing technology that can simulate the actual environment and the elucidation of the corrosion-controlling factor of the cladding are desired. In cases of RIA (Reactivity Initiated Accident) and LOCA (Loss of Coolant Accident), it seems that the loss of ductility in zirconium alloys under heavy irradiation and boiling of high temperature water restricts the extension of fuel burnup. From preliminary evaluation on the high corrosion-resistance materials (austenitic stainless steel, iron or nickel base superalloys, titanium alloy, niobium alloy, vanadium alloy and ferritic stainless steel), stabilized austenitic stainless steels with a capability of future improvement and high-purity niobium alloys with a expectation of the good corrosion resistance were selected as candidate materials of ultra-high burnup cladding. (author)

  6. Multilayer (TiN, TiAlN) ceramic coatings for nuclear fuel cladding

    Science.gov (United States)

    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.

  7. Scratch Behaviors of Cr-Coated Zr-Based Fuel Claddings for Accident-Tolerant Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Ho; Kim, Il-Hyun; Kim, Hyun-Gil; Kim, Hyung-Kyu; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    As the progression of Fukushima accident is worsened by the runaway reaction at a high temperature above 1200 .deg. C, it is essential to ensure the stabilities of coating layers on conventional Zr-based alloys during normal operations as well as severe accident conditions. This is because the failures of coating layer result in galvanic corrosion phenomenon by potential difference between coating layer and Zr alloy. Also, it is possible to damage the coating layer during handling and manufacturing process by contacting structural components of a fuel assembly. So, adhesion strength is one of the key factors determining the reliability of the coating layer on conventional Zr-based alloy. In this study, two kinds of Cr-coated Zr-based claddings were prepared using arc ion plating (AIP) and direct laser (DL) coating methods. The objective is to evaluate the scratch deformation behaviors of each coating layers on Zr alloys. Large area spallation below normal load of about 15 N appeared to be the predominant mode of failure in the AIP coating during scratch test. However, no tensile crack were found in entire stroke length. In DL coating, small plastic deformation and grooving behavior are more dominant scratching results. It was observed that the change of the slope of the COF curve did not coincide with the failure of coating layer.

  8. Report on Reactor Physics Assessment of Candidate Accident Tolerant Fuel Cladding Materials in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, Nathan [Univ. of Tennessee, Knoxville, TN (United States); Maldonado, G. Ivan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-28

    This work focuses on ATF concepts being researched at Oak Ridge National Laboratory (ORNL), expanding on previous studies of using alternate cladding materials in pressurized water reactors (PWRs). The neutronic performance of two leading alternate cladding materials were assessed in boiling water reactors (BWRs): iron-chromium-aluminum (FeCrAl) cladding, and silicon carbide (SiC)-based composite cladding. This report fulfills ORNL Milestone M3FT-15OR0202332 within the fiscal year 2015 (FY15)

  9. A deformation and thermodynamic model for hydride precipitation kinetics in spent fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Stout, R.B.

    1989-10-01

    Hydrogen is contained in the Zircaloy cladding of spent fuel rods from nuclear reactors. All the spent fuel rods placed in a nuclear waste repository will have a temperature history that decreases toward ambient; and as a result, most all of the hydrogen in the Zircaloy will eventually precipitate as zirconium hydride platelets. A model for the density of hydride platelets is a necessary sub-part for predicting Zircaloy cladding failure rate in a nuclear waste repository. A model is developed to describe statistically the hydride platelet density, and the density function includes the orientation as a physical attribute. The model applies concepts from statistical mechanics to derive probable deformation and thermodynamic functionals for cladding material response that depend explicitly on the hydride platelet density function. From this model, hydride precipitation kinetics depend on a thermodynamic potential for hydride density change and on the inner product of a stress tensor and a tensor measure for the incremental volume change due to hydride platelets. The development of a failure response model for Zircaloy cladding exposed to the expected conditions in a nuclear waste repository is supported by the US DOE Yucca Mountain Project. 19 refs., 3 figs.

  10. Oxidation resistant chromium coating on Zircaloy-4 for accident tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung-Hwan; Kim, Eui-Jung; Jung, Yang-Il; Park, Dong-Jun; Kim, Hyun-Gil; Park, Jeong-Yong; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The attributes of such a fuel are approved reaction kinetics with steam, a slower hydrogen generation rate, and good cladding thermo-mechanical properties. Many researchers have tried to modify zirconium alloys to improve their oxidation resistance in the early stages of the ATF development. Corrosion resistant coating on cladding is one of the candidate technologies to improve the oxidation resistance of zirconium cladding. By applying coating technology to zirconium cladding, it is easy to obtain corrosion resistance without a change in the base materials. Among the surface coating methods, arc ion plating (AIP) is a coating technology to improve the adhesion owing to good throwing power, and a dense deposit (Fig. 1). Owing to these advantages, AIP has been widely used to efficiently form protective coatings on cutting tools, dies, bearings, etc. In this study, The AIP technique for the protection of zirconium claddings from the oxidation in a high-temperature steam environment was studied. The homogeneous Cr film with a high adhesive ability to the cladding was deposited by AIP and acted as a protection layer to enhance the corrosion resistance of the zirconium cladding. It was concluded that the AIP technology is effective for coating a protective layer on claddings.

  11. Review of experimental data for modelling LWR fuel cladding behaviour under loss of coolant accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Massih, Ali R. [Quantum Technologies AB, Uppsala Science Park (Sweden)

    2007-02-15

    Extensive range of experiments has been conducted in the past to quantitatively identify and understand the behaviour of fuel rod under loss-of-coolant accident (LOCA) conditions in light water reactors (LWRs). The obtained experimental data provide the basis for the current emergency core cooling system acceptance criteria under LOCA conditions for LWRs. The results of recent experiments indicate that the cladding alloy composition and high burnup effects influence LOCA acceptance criteria margins. In this report, we review some past important and recent experimental results. We first discuss the background to acceptance criteria for LOCA, namely, clad embrittlement phenomenology, clad embrittlement criteria (limitations on maximum clad oxidation and peak clad temperature) and the experimental bases for the criteria. Two broad kinds of test have been carried out under LOCA conditions: (i) Separate effect tests to study clad oxidation, clad deformation and rupture, and zirconium alloy allotropic phase transition during LOCA. (ii) Integral LOCA tests, in which the entire LOCA sequence is simulated on a single rod or a multi-rod array in a fuel bundle, in laboratory or in a tests and results are discussed and empirical correlations deduced from these tests and quantitative models are conferred. In particular, the impact of niobium in zirconium base clad and hydrogen content of the clad on allotropic phase transformation during LOCA and also the burst stress are discussed. We review some recent LOCA integral test results with emphasis on thermal shock tests. Finally, suggestions for modelling and further evaluation of certain experimental results are made.

  12. Hydrogen uptake in Zircaloy-2 reactor fuel claddings studied with elastic recoil detection

    Science.gov (United States)

    Rajasekhara, S.; Doyle, B. L.; Enos, D. G.; Clark, B. G.

    2013-04-01

    The recent trend towards a high burn-up discharge spent nuclear fuel necessitates a thorough understanding of hydrogen uptake in Zr-based cladding materials that encapsulate spent nuclear fuel. Although it is challenging to experimentally replicate exact conditions in a nuclear reactor that lead to hydrogen uptake in claddings, in this study we have attempted to understand the kinetics of hydrogen uptake by first electrolytically charging Zircaloy-2 (Zr-2) cladding material for various durations (100 to 2,600 s), and subsequently examining hydrogen ingress with elastic recoil detection (ERD) and transmission electron microscopy (TEM). To understand the influence of irradiation damage defects on hydrogen uptake, an analogous study was performed on ion - irradiated (0.1, 1 and 25 dpa) Zr-2. Analysis of ERD data from the un-irradiated Zr-2 suggests that the growth of the hydride layer is diffusion controlled, and preliminary TEM results support this assertion. In un-irradiated Zr-2, the diffusivity of hydrogen in the hydride phase was found to be approximately 1.1 × 10-11 cm2/s, while the diffusivity in the hydride phase for lightly irradiated (0.1 and 1 dpa) Zr-2 is an order of magnitude lower. Irradiation to 25 dpa results in a hydrogen diffusivity that is comparable to the un-irradiated Zr-2. These results are compared with existing literature on hydrogen transport in Zr - based materials.

  13. Modelling anelastic contribution to nuclear fuel cladding creep and stress relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Tulkki, Ville, E-mail: ville.tulkki@vtt.fi; Ikonen, Timo

    2015-10-15

    In fuel behaviour modelling accurate description of the cladding mechanical response is important for both operational and safety considerations. While accuracy is desired, a certain level of simplicity is needed as both computational resources and detailed information on properties of particular cladding may be limited. Most models currently used in the integral codes divide the mechanical response into elastic and viscoplastic contributions. These have difficulties in describing both creep and stress relaxation, and often separate models for the two phenomena are used. In this paper we implement anelastic contribution to the cladding mechanical model, thus enabling consistent modelling of both creep and stress relaxation. We show that the model based on assumption of viscoelastic behaviour can be used to explain several experimental observations in transient situations and compare the model to published set of creep and stress relaxation experiments performed on similar samples. Based on the analysis presented we argue that the inclusion of anelastic contribution to the cladding mechanical models provides a way to improve the simulation of cladding behaviour during operational transients.

  14. Multilayer (TiN, TiAlN) ceramic coatings for nuclear fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Alat, Ece, E-mail: exa179@psu.edu [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Motta, Arthur T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Comstock, Robert J.; Partezana, Jonna M. [Westinghouse Electric Co., Beulah Rd, Pittsburgh, PA 1332 (United States); Wolfe, Douglas E. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Applied Research Laboratory, The Pennsylvania State University, 119 Materials Research Building, University Park, PA 16802 (United States)

    2016-09-15

    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{sup ®} coupon substrates by cathodic arc physical vapor deposition (CA-PVD). Coatings were composed of alternating TiN (top) and Ti{sub 1-x}Al{sub x}N (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/dm{sup 2} weight gain, which is 6 times smaller than that of a control sample of uncoated ZIRLO{sup ®} which showed a weight gain of 40.2 mg/dm{sup 2}. 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. - Highlights: • The first study on multilayer TiAlN and TiN ceramic coatings on ZIRLO{sup ®} coupons. • Corrosion tests were performed at 360°C and 18.7 MPa for up to 90 days. • Coatings adhered well to the substrate, and showed no spallation/delamination. • Weight gains were six times lower than those of uncoated ZIRLO{sup ®} samples. • Longer and higher temperature corrosion tests will be discussed in a further paper.

  15. Alloy Selection for Accident Tolerant Fuel Cladding in Commercial Light Water Reactors

    Science.gov (United States)

    Rebak, Raul B.

    2015-12-01

    As a consequence of the March 2011 events at the Fukushima site, the U.S. congress asked the Department of Energy (DOE) to concentrate efforts on the development of nuclear fuels with enhanced accident tolerance. The new fuels had to maintain or improve the performance of current UO2-zirconium alloy rods during normal operation conditions and tolerate the loss of active cooling in the core for a considerably longer time period than the current system. DOE is funding cost-shared research to investigate the behavior of advanced steels both under normal operation conditions in high-temperature water [ e.g., 561 K (288 °C)] and under accident conditions for reaction with superheated steam. Current results show that, under accident conditions, the advanced ferritic steels (1) have orders of magnitude lower reactivity with steam, (2) would generate less hydrogen and heat than the current zirconium alloys, (3) are resistant to stress corrosion cracking under normal operation conditions, and (4) have low general corrosion in water at 561 K (288 °C).

  16. Evaluation of Corrosion of Aluminum Based Reactor Fuel Cladding Materials During Dry Storage

    Energy Technology Data Exchange (ETDEWEB)

    Peacock, H.B. Jr.

    1999-10-21

    This report provides an evaluation of the corrosion behavior of aluminum cladding alloys and aluminum-uranium alloys at conditions relevant to dry storage. The details of the corrosion program are described and the results to date are discussed.

  17. Evidence for excited-state intramolecular proton transfer in 4-chlorosalicylic acid from combined experimental and computational studies: Quantum chemical treatment of the intramolecular hydrogen bonding interaction

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bijan Kumar [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India); Guchhait, Nikhil, E-mail: nikhil.guchhait@rediffmail.com [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Experimental and computational studies on the photophysics of 4-chlorosalicylic acid. Black-Right-Pointing-Pointer Spectroscopically established ESIPT reaction substantiated by theoretical calculation. Black-Right-Pointing-Pointer Quantum chemical treatment of IMHB unveils strength, nature and directional nature. Black-Right-Pointing-Pointer Superiority of quantum chemical treatment of H-bond over geometric criteria. Black-Right-Pointing-Pointer Role of H-bond as a modulator of aromaticity. -- Abstract: The photophysical study of a pharmaceutically important chlorine substituted derivative of salicylic acid viz., 4-chlorosalicylic acid (4ClSA) has been carried out by steady-state absorption, emission and time-resolved emission spectroscopy. A large Stokes shifted emission band with negligible solvent polarity dependence marks the spectroscopic signature of excited-state intramolecular proton transfer (ESIPT) reaction in 4ClSA. Theoretical calculation by ab initio and Density Functional Theory methods yields results consistent with experimental findings. Theoretical potential energy surfaces predict the occurrence of proton transfer in S{sub 1}-state. Geometrical and energetic criteria, Atoms-In-Molecule topological parameters, Natural Bond Orbital population analysis have been exploited to evaluate the intramolecular hydrogen bond (IMHB) interaction and to explore its directional nature. The inter-correlation between aromaticity and resonance assisted H-bond is also discussed in this context. Our results unveil that the quantum chemical treatment is a more accurate tool to assess hydrogen bonding interaction in comparison to geometrical criteria.

  18. Chemical Potential for the Interacting Classical Gas and the Ideal Quantum Gas Obeying a Generalized Exclusion Principle

    Science.gov (United States)

    Sevilla, F. J.; Olivares-Quiroz, L.

    2012-01-01

    In this work, we address the concept of the chemical potential [mu] in classical and quantum gases towards the calculation of the equation of state [mu] = [mu](n, T) where n is the particle density and "T" the absolute temperature using the methods of equilibrium statistical mechanics. Two cases seldom discussed in elementary textbooks are…

  19. Preparation and characterization of chemical gradient surfaces and their application for the study of cellular interaction phenomena

    NARCIS (Netherlands)

    Ruardy, TG; Schakenraad, JM; vanderMei, HC; Busscher, HJ

    1997-01-01

    Chemical gradient surfaces are surfaces with a gradually changing chemistry along their length which is responsible for a position bound variation in physical properties, most notably, the wettability. In this review, methods to prepare (palladium deposition, diffusion technique, density gradient me

  20. Alteration of gene expression in human cells treated with the agricultural chemical diazinon: possible interaction in fetal development.

    Science.gov (United States)

    Mankame, T; Hokanson, R; Fudge, R; Chowdhary, R; Busbee, D

    2006-05-01

    Agricultural chemicals frequently alter human health or development, typically because they have endocrine agonist or antagonist activities and alter hormone-regulation of gene expression. The insecticide, diazinon, was evaluated for gene expression disrupting activity using MCF-7 cells, an estrogen-dependent human cell line, to examine the capacity of the insecticide to disrupt gene expression essential for morphological development, immune system development or function, and/or central nervous system development and function. MCF-7 cells were treated with 30, 50 or 67 ppm diazinon, and gene expression was measured in treated cells compared to expression in untreated or estrogen-treated cells. DNA microarray analysis of diazinon-treated cells showed significant up- or down-regulation of a large number of genes compared to untreated cells. Of the 600 human genes on the Phase 1 chip utilized for these studies, two specific genes--calreticulin and TGF-beta3--were selected for corroboration using quantitative real time PCR (qrtPCR). qrtPCR, completed to assess gene expression levels for calreticulin and TGFbeta3, confirmed results showing significant up-regulation of these two genes obtained from the microarray data. These studies were designed to provide baseline data on the gene expression-altering capacity of a specific chemical, diazinon, and allow a partial assessment of the potentially deleterious effects associated with exposure of human cells to this chemical. Currently, it is not known whether results from cells in vitro can be extrapolated to human health consequences of chemical exposure.

  1. Chemical and enzymatic interactions of Direct Black 38 and Direct Brown 1 on release of carcinogenic amines.

    Science.gov (United States)

    Gnanamani, A; Bhaskar, M; Ganga, Radhakrishnan; Sekaran, G; Sadulla, S

    2004-09-01

    Release of amine products from azo compounds is of considerable interest, since most of the metabolized amine products have toxic and carcinogenic characters. Moreover, most of the azo dyes are extensively used as coloring agents in inks, textiles, leathers, food and pharmaceutical industries. The present study emphasis on the quantification and comparison of amines released from water soluble dyes by (i) extra cellular protein (ECP) of Streptomyces sp. SS07 and by (ii) chemical methods. It has been observed that both the methods release considerable quantities of similar type of amine products. Release of amine compounds by ECP and chemical reduction in acid and alkaline sweat medium from a leather garment sample was also assessed. ECP (0.7852 mg protein/mg of ECP) releases benzidine and 4-amino biphenyl from Direct Black 38 and Direct Brown 1 as stable products at pH 9.2 and at 37 degrees C for a contact period of 24 h. On comparison with chemical reduction, it was observed that about 5-20% increase in the release of amine products by ECP was observed. However, more than 60% of amine products were released by chemical method from leather garment samples than direct treatment with ECP.

  2. Chemical Potential for the Interacting Classical Gas and the Ideal Quantum Gas Obeying a Generalized Exclusion Principle

    Science.gov (United States)

    Sevilla, F. J.; Olivares-Quiroz, L.

    2012-01-01

    In this work, we address the concept of the chemical potential [mu] in classical and quantum gases towards the calculation of the equation of state [mu] = [mu](n, T) where n is the particle density and "T" the absolute temperature using the methods of equilibrium statistical mechanics. Two cases seldom discussed in elementary textbooks are…

  3. Preparation and characterization of chemical gradient surfaces and their application for the study of cellular interaction phenomena

    NARCIS (Netherlands)

    Ruardy, TG; Schakenraad, JM; vanderMei, HC; Busscher, HJ

    1997-01-01

    Chemical gradient surfaces are surfaces with a gradually changing chemistry along their length which is responsible for a position bound variation in physical properties, most notably, the wettability. In this review, methods to prepare (palladium deposition, diffusion technique, density gradient me

  4. Cross correlations between {sup 13}C-{sup 1}H dipolar interactions and {sup 15}N chemical shift anisotropy in nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Ravindranathan, Sapna [Institut de Chimie Moleculaire et Biologique, Ecole Polytechnique Federale de Lausanne, BCH (Switzerland); Kim, Chul-Hyun [University of California, Department of Chemistry (United States); Bodenhausen, Geoffrey [Institut de Chimie Moleculaire et Biologique, Ecole Polytechnique Federale de Lausanne, BCH (Switzerland)], E-mail: Geoffrey.Bodenhausen@ens.fr

    2003-12-15

    Two sets of cross-correlated relaxation rates involving chemical shift anisotropy and dipolar interactions have been measured in an RNA kissing complex. In one case, both the CSA and dipolar interaction tensors are located on the same nucleotide base and are rigidly fixed with respect to each other. In the other case, the CSA tensor is located on the nucleotide base whereas the dipolar interaction is located on the adjoining ribose unit. Analysis of the measured rates in terms of isotropic or anisotropic rotational diffusion has been carried out for both cases. A marked difference between the two models is observed for the cross-correlation rates involving rigidly fixed spin interactions. The influence of internal motions about the glycosidic linkage between the nucleotide base and the ribose unit on cross-correlated relaxation rates has been estimated by applying a model of restricted rotational diffusion. Local motions seem to have a more pronounced effect on cross-correlated relaxation rates when the two spin interactions are not rigidly fixed with respect to each other.

  5. Effect of ionic interaction between a hyperpolarized magnetic resonance chemical probe and a gadolinium contrast agent for the hyperpolarized lifetime after dissolution

    Science.gov (United States)

    Takakusagi, Yoichi; Inoue, Kaori; Naganuma, Tatsuya; Hyodo, Fuminori; Ichikawa, Kazuhiro

    2016-09-01

    In hyperpolarization of 13C-enriched magnetic resonance chemical probes in the solid-state, a trace amount of gadolinium (Gd) contrast agent can be used to maximize polarization of the 13C nuclear spins. Here, we report systematic measurement of the spin-lattice relaxation time (T1) and enhancement level of 13C-enriched chemical probes in the presence of various Gd contrast agents in the liquid-state after dissolution. Using two different 13C probes having opposite electric charges at neutral pH, we clearly show the T1 of hyperpolarized 13C was barely affected by the use of a Gd complex that displays repulsive interaction with the 13C probe in solution, whilst T1 was drastically shortened when there was ionic attraction between probe and complex.

  6. Interaction of Two Water Soluble Heterocyclic Hydrazones on Copper in Nitric Acid: Electrochemical, Surface Morphological, and Quantum Chemical Investigations

    Directory of Open Access Journals (Sweden)

    Vinod P. Raphael

    2016-01-01

    Full Text Available Two novel heterocyclic compounds (E-2-(1-(pyridin-3-ylethylidenehydrazinecarbothioamide (3APTSC and (E-3-(1-(2-phenylhydrazonoethylpyridine (3APPH derived from 1-(pyridin-3-ylethanone were synthesized and characterized by various spectroscopic techniques. The corrosion inhibition efficacies of these compounds on copper in 0.1 M HNO3 were screened by electrochemical corrosion monitoring techniques such as potentiodynamic polarization studies and impedance spectroscopy. Investigations clearly established that 3APPH displayed higher corrosion inhibition efficiency on Cu than 3APTSC at all concentrations. The mechanism of inhibition was verified with the help of adsorption isotherms. 3APTSC and 3APPH obeyed Langmuir adsorption isotherm on Cu surface. Thermodynamic parameters such as adsorption equilibrium constant (Kads and free energy of adsorption (ΔGads were also evaluated. Potentiodynamic polarization investigations confirmed that the 3APTSC and 3APPH act as mixed type inhibitors. Surface analysis of the metal specimens was performed by scanning electron microscopy. Energy of HOMO and LUMO, their difference, number of electrons transferred, electronegativity, chemical hardness, and so forth were evaluated by quantum chemical studies. Agreeable correlation was observed between the results of quantum chemical calculations and other corrosion monitoring techniques.

  7. Isotopic, chemical and dissolved gas constraints on spring water from Popocatepetl volcano (Mexico): evidence of gas water interaction between magmatic component and shallow fluids

    Science.gov (United States)

    Inguaggiato, S.; Martin-Del Pozzo, A. L.; Aguayo, A.; Capasso, G.; Favara, R.

    2005-03-01

    Geochemical research was carried out on cold and hot springs at Popocatepetl (Popo) volcano (Mexico) in 1999 to identify a possible relationship with magmatic activity. The chemical and isotopic composition of the fluids is compatible with strong gas-water interaction between deep and shallow fluids. In fact, the isotopic composition of He and dissolved carbon species is consistent with a magmatic origin. The presence of a geothermal system having a temperature of 80-100° C was estimated on the basis of liquid geothermometers. A large amount of dissolved CO 2 in the springs was also detected and associated with high CO 2 degassing.

  8. Advanced fast reactor fuels program. Second annual progress report, July 1, 1975--September 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.D. (comp.)

    1978-12-01

    Results of steady-state (EBR-II) irradiation testing, off-normal irradiation design and testing, fuel-cladding compatibility, and chemical stability of uranium--plutonium carbide and nitride fuels are presented.

  9. A Brief Introduction to a Major Project--The Physical-Chemical Processes in the Lower Atmosphere and Their Interaction with the Ecological System over the Yangtze Delta

    Institute of Scientific and Technical Information of China (English)

    Luo Yunfeng; Zhou Xiaogang

    2005-01-01

    With rapid industrialization and agricultural modernization in the past two decades, the Yangtze Delta Region in China has been one of the regions in the world most influenced by human activity. How has the economic development impacted on ecosystem, environment, agriculture and regional climate in this region ? What are the mechanisms of the interactive processes and feedbacks? What will be the future changes under different development scenarios? These are questions of critical importance to sustain the rate of social and economic development. A Major Project, The Physical-Chemical Processes in the Lower Atmosphere and Their Interaction with the Ecological System over Yangtze Delta,as one of the Ninth Five-Year Major Programs (1996-2000) funded by the National Natural Science Foundation of China, NSFC, just focused on those questions. Under the leadership of Prof. Zhou Xiuji, academician of the Chinese Academy of Sciences this project has made significant achievements and great progress in answering the above questions.

  10. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP: linking condensation, evaporation and chemical reactions of organics, oxidants and water

    Directory of Open Access Journals (Sweden)

    M. Shiraiwa

    2011-12-01

    Full Text Available We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007, and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds.

    In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the

  11. An Interactive Multimedia Tutorial Teaching Unit and Its Effects on Student Perception and Understanding of Chemical Concepts.

    Science.gov (United States)

    Vrtacnik, M.; Sajovec, M.; Dolnicar, D.; Pucko-Razdevsek, C.; Glazar, A.; Brouwer, N. Zupancic

    2000-01-01

    Investigates the effects of teaching with an interactive tutorial multimedia unit on students' understanding of concepts presented in the unit and their perceptions of the learning environment. Discusses the results and concludes that the multimedia unit shows promising effects on students' acquisition of knowledge. (CMK)

  12. The action and interaction of calcium and alkali chlorides on eggs of Limnaea stagnalis and their chemical interpretation

    NARCIS (Netherlands)

    Geilenkirchen, W.L.M.

    1964-01-01

    1. 1. The action and interaction of CaCl2 and alkali chlorides on eggs of Limnaea stagnalis have been studied. 2. 2. CaCl2 antagonizes death caused by alkali chlorides. The number of normally developing embryos increases in all cases. 3. 3. Alkali chlorides antagonize death caused by CaCl2. With NaC

  13. A quantum-chemical validation about the formation of hydrogen bonds and secondary interactions in intermolecular heterocyclic systems

    Directory of Open Access Journals (Sweden)

    Boaz Galdino Oliveira

    2009-08-01

    Full Text Available We have performed a detailed theoretical study in order to understand the charge density topology of the C2H4O···C2H2 and C2H4S···C2H2 heterocyclic hydrogen-bonded complexes. Through the calculations derived from Quantum Theory of Atoms in Molecules (QTAIM, it was observed the formation of hydrogen bonds and secondary interactions. Such analysis was performed through the determination of optimized geometries at B3LYP/6-31G(d,p level of theory, by which is that QTAIM topological operators were computed, such as the electronic density ρ(r, Laplacian Ñ2ρ(r, and ellipticity ε. The examination of the hydrogen bonds has been performed through the measurement of ρ(r, Ñ2ρ(r and ε between (O···H—C and (S···H—C, whereas the secondary interaction between axial hydrogen atoms Hα and carbon of acetylene. In this insight, it was verified the existence of secondary interaction only in C2H4S···C2H2 complex because its structure is propitious to form multiple interactions.

  14. Interactions with combined chemical cues inform harvester ant foragers' decisions to leave the nest in search of food.

    Science.gov (United States)

    Greene, Michael J; Pinter-Wollman, Noa; Gordon, Deborah M

    2013-01-01

    Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus) regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food.

  15. Interactions with combined chemical cues inform harvester ant foragers' decisions to leave the nest in search of food.

    Directory of Open Access Journals (Sweden)

    Michael J Greene

    Full Text Available Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food.

  16. Chemical interactions study of antiretroviral drugs efavirenz and lamivudine concerning the development of stable fixed-dose combination formulations for AIDS treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Elionai C. de L.; Mussel, Wagner N.; Resende, Jarbas M.; Yoshida, Maria I., E-mail: mirene@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Instituto de Ciencias Exatas. Departamento de Quimica; Fialho, Silvia L.; Barbosa, Jamile; Fialho, Silvia L. [Fundacao Ezequiel Dias, Belo Horizonte, MG (Brazil)

    2013-04-15

    Lamivudine and efavirenz are among the most worldwide used drugs for acquired immune deficiency syndrome (AIDS) treatment. Solid state nuclear magnetic resonance (ssNMR), Fourier-transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermo-optical analysis (TOA) were used to study possible interactions between these drugs, aiming the development of a fixed-dose drug combination. DSC and TOA have evidenced significant shifts on the melting points of both drugs in the mixture, which may be due to interaction between them. Although DSC and TOA results indicated incompatibility between the drugs, FTIR spectra were mostly unmodified due to overlapping peaks. The ssNMR analyses showed significant changes in chemical shifts values of the mixture when compared with spectra of pure drugs, especially in the signals relating to the deficient electron carbon atoms of both drugs. These results confirm the interactions suggested by DSC and TOA, which is probably due to acid-base interactions between electronegative and deficient electron atoms of both lamivudine and efavirenz. (author)

  17. Role of the chemical bonding for the time-dependent electron transport through an interacting quantum dot

    KAUST Repository

    Goker, Ali

    2011-06-01

    A combination of ab initio and many-body calculations is utilized to determine the effects of the bonding in Au electrodes on the time dependent current through a quantum dot suddenly shifted into the Kondo regime by a gate voltage. For an asymmetrically coupled system the instantaneous conductance exhibits fluctuations. The frequencies of the fluctuations turn out to be proportional to the energetic separation between the dominating peaks in the density of states and the Fermi level. The chemical bonding in the electrodes, thus, drastically alters the transient current, which can be accessed by ultrafast pump-probe techniques. © 2011 Elsevier B.V. All rights reserved.

  18. Interaction of biochar and organic residues from sugarcane industry in soil chemical attributes and greenhouse gases emissions.

    Science.gov (United States)

    Fernanda Abbruzzini, Thalita; Feola Conz, Rafaela; Pellegrino Cerri, Carlos Eduardo

    2014-05-01

    Researchers have highlighted the importance of providing soil quality in agricultural systems, besides mitigating greenhouse gases (GHG) emissions to the atmosphere and increasing soil carbon sequestration. Therefore, several studies have demonstrated the effectiveness of biochar as a soil conditioner, both in relation to increased C sequestration and improvements in soil chemical, physical and biological attributes, resulting in better conditions for plant growth. The aim of this study was to assess the impact of applying biochar produced from sugarcane straw to soils in relation to changes in soil chemical attributes and mitigation of greenhouse gases emissions into the atmosphere. To do so, we conducted a laboratory incubation under controlled environmental conditions (ie temperature and humidity) with and without the application of filter cake and vinasse (ie organic residues from sugarcane industry) and rates of biochar application (0, 10, 20 and 50 Mg ha-1). The fluxes of CO2, N2O and CH4 of each incubation unity were measured periodically (in days 1, 2, 5, 9, 13, 16, 20, 24, 28, 30, 47, 60, 91, 105, 123, 130, 138 and 150). Each treatment consisted of eight replicates with destructive samples evaluated at 30, 60, 90 and 150 days after incubation to characterize the chemical attributes of the incubated soil, besides GHG (CO2, N2O and CH4) emissions. In general, there was an increase in carbon dioxide (CO2) fluxes over time due to the application of filter cake and vinasse and increasing dose of biochar. Regarding nitrous oxide (N2O) emissions, there was an increase of 82.35% with the application of vinasse and filter cake compared to the control treatment. However, different doses of biochar (10, 20 and 50 Mg ha-1) reduced N2O emissions by 29, 38.7 and 70.9%, respectively. The methane (CH4) flux was negligible in all treatments. We observed improvements in soil chemical attributes, such as higher pH, a substantial increase in the soil CEC, reduced exchangeable

  19. Glyphosate sorption/desorption on biochars - interactions of physical and chemical processes.

    Science.gov (United States)

    Hall, Kathleen E; Spokas, Kurt A; Gamiz, Beatriz; Cox, Lucia; Papiernik, Sharon K; Koskinen, William C

    2017-01-23

    Biochar, a carbon-rich product of biomass pyrolysis, could limit glyphosate transport in soil and remediate contaminated water. The present study investigates the sorption/desorption behavior of glyphosate on biochars prepared from different hardwoods at temperatures ranging from 350 to 900 °C to elucidate fundamental mechanisms. Glyphosate (1 mg L(-1) ) sorption on biochars increased with pyrolysis temperature and was highest on 900 °C biochars; however, total sorption was low on a mass basis (glyphosate in soils, did not alter biochar sorption capacities. Glyphosate did not desorb from biochar with CaCl2 solution; however, up to 86% of the bound glyphosate was released with a K2 HPO4 solution. Results from this study suggest a combined impact of surface chemistry and physical constraints on glyphosate sorption/desorption on biochar. Based on the observed phosphate-induced desorption of glyphosate, the addition of P-fertilizer to biochar-amended soils can remobilize the herbicide and damage non-target plants; therefore, improved understanding of this risk is necessary. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Plasma-enhanced chemical vapor deposition of ortho-carborane: structural insights and interaction with Cu overlayers.

    Science.gov (United States)

    James, Robinson; Pasquale, Frank L; Kelber, Jeffry A

    2013-09-01

    X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) are used to investigate the chemical and electronic structure of boron carbide films deposited from ortho-carborane precursors using plasma-enhanced chemical vapor deposition (PECVD), and the reactivity of PECVD films toward sputter-deposited Cu overlayers. The XPS data provide clear evidence of enhanced ortho-carborane reactivity with the substrate, and of extra-icosahedral boron and carbon species; these results differ from results for films formed by condensation and electron beam induced cross-linking of ortho-carborane (EBIC films). The UPS data show that the valence band maximum for PECVD films is ∼1.5 eV closer to the Fermi level than for EBIC films. The XPS data also indicate that PECVD films are resistant to thermally-stimulated diffusion of Cu at temperatures up to 1000 K in UHV, in direct contrast to recently reported results, but important for applications in neutron detection and in microelectronics.

  1. Chemical interactions between plants in Mediterranean vegetation: the influence of selected plant extracts on Aegilops geniculata metabolome.

    Science.gov (United States)

    Scognamiglio, Monica; Fiumano, Vittorio; D'Abrosca, Brigida; Esposito, Assunta; Choi, Young Hae; Verpoorte, Robert; Fiorentino, Antonio

    2014-10-01

    Allelopathy is the chemical mediated communication among plants. While on one hand there is growing interest in the field, on the other hand it is still debated as doubts exist at different levels. A number of compounds have been reported for their ability to influence plant growth, but the existence of this phenomenon in the field has rarely been demonstrated. Furthermore, only few studies have reported the uptake and the effects at molecular level of the allelochemicals. Allelopathy has been reported on some plants of Mediterranean vegetation and could contribute to structuring this ecosystem. Sixteen plants of Mediterranean vegetation have been selected and studied by an NMR-based metabolomics approach. The extracts of these donor plants have been characterized in terms of chemical composition and the effects on a selected receiving plant, Aegilops geniculata, have been studied both at the morphological and at the metabolic level. Most of the plant extracts employed in this study were found to have an activity, which could be correlated with the presence of flavonoids and hydroxycinnamate derivatives. These plant extracts affected the receiving plant in different ways, with different rates of growth inhibition at morphological level. The results of metabolomic analysis of treated plants suggested the induction of oxidative stress in all the receiving plants treated with active donor plant extracts, although differences were observed among the responses. Finally, the uptake and transport into receiving plant leaves of different metabolites present in the extracts added to the culture medium were observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Chemical analysis and molecular models for calcium-oxygen-carbon interactions in black carbon found in fertile Amazonian anthrosoils.

    Science.gov (United States)

    Archanjo, Braulio S; Araujo, Joyce R; Silva, Alexander M; Capaz, Rodrigo B; Falcão, Newton P S; Jorio, Ado; Achete, Carlos A

    2014-07-01

    Carbon particles containing mineral matter promote soil fertility, helping it to overcome the rather unfavorable climate conditions of the humid tropics. Intriguing examples are the Amazonian Dark Earths, anthropogenic soils also known as "Terra Preta de Índio'' (TPI), in which chemical recalcitrance and stable carbon with millenary mean residence times have been observed. Recently, the presence of calcium and oxygen within TPI-carbon nanoparticles at the nano- and mesoscale ranges has been demonstrated. In this work, we combine density functional theory calculations, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transformed infrared spectroscopy, and high resolution X-ray photoelectron spectroscopy of TPI-carbons to elucidate the chemical arrangements of calcium-oxygen-carbon groups at the molecular level in TPI. The molecular models are based on graphene oxide nanostructures in which calcium cations are strongly adsorbed at the oxide sites. The application of material science techniques to the field of soil science facilitates a new level of understanding, providing insights into the structure and functionality of recalcitrant carbon in soil and its implications for food production and climate change.

  3. EFFECT OF CHEMICAL AND ORGANIC SOIL FERTILIZERS AND THEIR INTERACTIONS WITH SOME FOLIAR FERTILIZERS ON GROWTH AND YIELD OF BROAD BEAN (VICIA FABA L

    Directory of Open Access Journals (Sweden)

    Ali Husain JASIM

    2016-12-01

    Full Text Available Field experiment was conducted at the field of Agriculture College, Al-Qasim Green University at the agricultural season 2014/2015 to study the effect of two soil fertilizers (compound 18-18-18- at the rate of 200 kg.ha-1and sheep manure as organic fertilizer at the rate of 10 tons.ha-1 as well as control, and their interaction with foliar fertilizer of sea weed extract and urea as well as control (without the spray on broad bean plants. Randomized Complete Block Design was used with three replication. The experimental unit contained 3 ridges (3m long and 80 cm apart, planted on both sides at distance of 25 cm in saline soil (9.6dS.m-1. The results showed that chemical or organic soil fertilization led to increase plant height, plant branches number, plant leaves, leaf chlorophyll content and leaf percentage content of nitrogen, phosphorus and potassium significantly compared to control treatment. Add compost Chemical. On the other foliar fertilizer caused a significant increase in all traits above compared to control (without spraying. The interaction between soil and foliar fertilizers had a significant effect on all traits above.

  4. A Model for Generation of Martian Surface Dust, Soil and Rock Coatings: Physical vs. Chemical Interactions, and Palagonitic Plus Hydrothermal Alteration

    Science.gov (United States)

    Bishop, J. L.; Murchie, S.; Pieters, C.; Zent, A.

    1999-01-01

    This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data from Mars and geologic analogs from terrestrial sites. One basic premise is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results. Physical processes distribute dust particles on rocks, forming physical rock coatings, and on the surface between rocks forming soil units; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces or duricrust surface units, both of which are relatively permanent materials. According to this model the mineral components of the dust/soil particles are derived from a combination of "typical" palagonitic weathering of volcanic ash and hydrothermally altered components, primarily from steam vents or fumeroles. Both of these altered materials are composed of tiny particles, about 1 micron or smaller, that are aggregates of silicates and iron oxide/oxyhydroxide/sulfate phases. Additional information is contained in the original extended abstract.

  5. All-atom Molecular Dynamic Simulations Combined with the Chemical Shifts Study on the Weak Interactions of Ethanol-water System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rong; LUO San-Lai; WU Wen-Juan

    2008-01-01

    All-atom molecular dynamics(MD)simulation combined with chemical shifts was performed to investigate the interactions over the entire concentration range of the ethanol(EtOH)-water system.The results of the simulation were adopted to explain the NMR experiments by hydrogen bonding analysis.The strong hydrogen bonds and weak C-H…O contacts coexist in the mixtures through the analysis of the radial distribution functions.And the liquid structures in the whole concentration of EtOH-water mixtures can be classified into three regions by the statistic analysis of the hydrogen-bonding network in the MD simulations.Moreover,the chemical shifts of the hydrogen atom are in agreement witb the statistical results of the average number hydrogen bonds in the MD simulations.Interestingly,the excess relative extent Eηrel calculated by the MD simulations and chemical shifts in the EtOH aqueous solutions shows the largest deviation at XEtOH≈0.18.The excess properties present good agreement with the excess enthalpy in the concentration dependence.

  6. Quantification of Interactions between Serum Albumin and Endogenous Free Fatty Acids or Exogenous Chemicals by Stable Isotope-Coded Mass Spectrometry.

    Science.gov (United States)

    Li, Tingting; Yue, Yingxia; Li, Jianjian; Wang, Xiaoli; Fu, Jieying; Zhong, Hongying

    2011-08-11

    As primary endogenous ligands of serum albumin, free fatty acids exert versatile effects on the albumin conformation through cooperative or competitive interactions with exogenous chemicals. Based on equilibrium partition between n-hexane and aqueous phases, we have established three indexes, defined as R A, R V, and R T, for quantitative assessment of the intrinsic binding affinity, the affinitive variation induced by exogenous chemicals, and the topological dependence of albumin affinity, respectively. When albumin molecules in the aqueous phase are in native or denatured forms, or disturbed by exogenous chemicals, corresponding changes of free fatty acids in the n-hexane phase can be quantified by an iFFAM (isotope-coded free fatty acid methylation) approach. Free fatty acids from the control and the sample are differentially derived by d0- or d3-methanol and analyzed by gas chromatography-mass spectrometry. Changes of fatty acids can be revealed by peak ratios of d0- or d3-labeled fragment ions of fatty acid methyl esters.

  7. Role of plant growth regulators as chemical signals in plant-microbe interactions: a double edged sword.

    Science.gov (United States)

    Spence, Carla; Bais, Harsh

    2015-10-01

    Growth regulators act not only as chemicals that modulate plant growth but they also act as signal molecules under various biotic and abiotic stresses. Of all growth regulators, abscisic acid (ABA) is long known for its role in modulating plants response against both biotic and abiotic stress. Although the genetic information for ABA biosynthesis in plants is well documented, the knowledge about ABA biosynthesis in other organisms is still in its infancy. It is known that various microbes including bacteria produce and secrete ABA, but the overall functional significance of why ABA is synthesized by microbes is not known. Here we discuss the functional involvement of ABA biosynthesis by a pathogenic fungus. Furthermore, we propose that ABA biosynthesis in plant pathogenic fungi could be targeted for novel fungicidal discovery.

  8. Enhancement of interaction of L-929 cells with functionalized graphene via COOH+ ion implantation vs. chemical method

    Science.gov (United States)

    Zhao, Meng-Li; Liu, Xiao-Qi; Cao, Ye; Li, Xi-Fei; Li, De-Jun; Sun, Xue-Liang; Gu, Han-Qing; Wan, Rong-Xin

    2016-11-01

    Low hydrophilicity of graphene is one of the major obstacles for biomaterials application. To create some hydrophilic groups on graphene is addressed this issue. Herein, COOH+ ion implantation modified graphene (COOH+/graphene) and COOH functionalized graphene were designed by physical ion implantation and chemical methods, respectively. The structure and surface properties of COOH+/graphene and COOH functionalized graphene were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurement. Compared with graphene, COOH+/graphene and COOH functionalized graphene revealed improvement of cytocompatibility, including in vitro cell viability and morphology. More importantly, COOH+/graphene exhibited better improvement effects than functionalized graphene. For instance, COOH+/graphene with 1 × 1018 ions/cm2 showed the best cell-viability, proliferation and stretching. This study demonstrated that ion implantation can better improve the cytocompatibility of the graphene.

  9. The origin and use of the terms competitive and non-competitive in interactions among chemical substances in biological systems.

    Science.gov (United States)

    McIlwain, H

    1986-01-01

    The terms competition and competitive were in use for appropriate types of interaction in human and animal behaviour from the seventeenth century. In the nineteenth and early twentieth centuries they reached more technical uses in biology, especially in darwinian studies; and in chemistry in describing competing reactions, surface phenomena and the influence of substituent groupings in reactant molecules. Use of competitive and non-competitive to describe enzyme inhibitors had a specific beginning when J. B. S. Haldane (following premonitory work of others) applied the terms in 1927 and 1930 to types of inhibition already differentiated by Michaelis and co-workers. The theoretical background in kinetics and stereochemistry so acquired gave a firmness to the application of the terms in biochemistry. The first examples concerned glycosidases, especially beta-D-fructofuranosidase or invertase, and interactions of carbon monoxide and oxygen at iron-porphyrin systems. They were thus of interest in toxicology and in enzyme and carrier studies. The sphere of application of the biochemically-defined terms expanded greatly when, following investigation of sulphonamide action, it was realized that concepts of enzyme inhibition by structurally related compounds offered a route to understanding the action of existing medicaments and to the production of new ones. Ideas and terminology based on competitive and non-competitive enzyme inhibition and receptor occupancy have subsequently been applied in many ways. Examples include application to the analysis of feedback inhibition and other processes of metabolic control; to receptor relationships among neurotransmitters and medicaments; and to understanding interactions at sensory receptors.

  10. The relevance of chemical interactions with CYP17 enzyme activity: Assessment using a novel in vitro assay

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Maarke J.E., E-mail: m.j.e.roelofs@uu.nl [Endocrine Toxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht (Netherlands); Center for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Piersma, Aldert H. [Endocrine Toxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht (Netherlands); Center for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Berg, Martin van den; Duursen, Majorie B.M. van [Endocrine Toxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht (Netherlands)

    2013-05-01

    The steroidogenic cytochrome P450 17 (CYP17) enzyme produces dehydroepiandrosterone (DHEA), which is the most abundant circulating endogenous sex steroid precursor. DHEA plays a key role in e.g. sexual functioning and development. To date, no rapid screening assay for effects on CYP17 is available. In this study, a novel assay using porcine adrenal cortex microsomes (PACMs) was described. Effects of twenty-eight suggested endocrine disrupting compounds (EDCs) on CYP17 activity were compared with effects in the US EPA validated H295R (human adrenocorticocarcinoma cell line) steroidogenesis assay. In the PACM assay DHEA production was higher compared with the H295R assay (4.4 versus 2.2 nmol/h/mg protein). To determine the additional value of a CYP17 assay, all compounds were also tested for interaction with CYP19 (aromatase) using human placental microsomes (HPMs) and H295R cells. 62.5% of the compounds showed enzyme inhibition in at least one of the microsomal assays. Only the cAMP inducer forskolin induced CYP17 activity, while CYP19 was induced by four test compounds in the H295R assay. These effects remained unnoticed in the PACM and HPM assays. Diethylstilbestrol and tetrabromobisphenol A inhibited CYP17 but not CYP19 activity, indicating different mechanisms for the inhibition of these enzymes. From our results it becomes apparent that CYP17 can be a target for EDCs and that this interaction differs from interactions with CYP19. Our data strongly suggest that research attention should focus on validating a specific assay for CYP17 activity, such as the PACM assay, that can be included in the EDC screening battery. - Highlights: ► DHEA, produced by CYP17, plays a key role in sexual functioning and development. ► No rapid screening assay for effects on CYP17 is available yet. ► A novel assay using porcine adrenal cortex microsomes (PACMs) was described. ► Endocrine disrupting compounds (EDCs) targeting CYP17 interact differently with CYP19. ► A

  11. Chemical modification of paclitaxel (Taxol) reduces P-glycoprotein interactions and increases permeation across the blood-brain barrier in vitro and in situ.

    Science.gov (United States)

    Rice, Antonie; Liu, Yanbin; Michaelis, Mary Lou; Himes, Richard H; Georg, Gunda I; Audus, Kenneth L

    2005-02-10

    The purpose of this work was to introduce a chemical modification into the paclitaxel (Taxol) structure to reduce interactions with the product of the multidrug resistant type 1 (MDR1) gene, P-glycoprotein (Pgp), resulting in improved blood-brain barrier (BBB) permeability. Specifically, a taxane analogue, Tx-67, with a succinate group added at the C10 position of Taxol, was synthesized and identified as such a candidate. In comparison studies, Tx-67 had no apparent interactions with Pgp, as demonstrated by the lack of enhanced uptake of rhodamine 123 by brain microvessel endothelial cells (BMECs) in the presence of the agent. By contrast, Taxol exposure substantially enhanced rhodamine 123 uptake by BMECs through inhibition of Pgp. The transport across BMEC monolayers was polarized for both Tx-67 and Taxol with permeation in the apical to basolateral direction greater for Tx-67 and substantially reduced for Taxol relative to basolateral to apical permeation. Taxol and cyclosporin A treatments also did not enhance Tx-67 permeation across BMEC monolayers. In an in situ rat brain perfusion study, Tx-67 was demonstrated to permeate across the BBB at a greater rate than Taxol. These results demonstrate that the Taxol analogue Tx-67 had a reduced interaction with Pgp and, as a consequence, enhanced permeation across the blood-brain barrier in vitro and in situ.

  12. Interaction between two contrasting magmas in the Albtal pluton (Schwarzwald, SW Germany): textural and mineral-chemical evidence

    Science.gov (United States)

    Michel, Lorenz; Wenzel, Thomas; Markl, Gregor

    2016-07-01

    The magmatic evolution of the Variscan Albtal pluton, Schwarzwald, SW Germany, is explored using detailed textural observations and the chemical composition of plagioclase and biotite in both granite and its mafic magmatic enclaves (MMEs). MMEs probably formed in a two-step process. First, mafic magma intruded a granitic magma chamber and created a boundary layer, which received thermal and compositional input from the mafic magma. This is indicated by corroded "granitic" quartz crystals and by large "granitic" plagioclase xenocrysts, which contain zones of higher anorthite and partly crystallized from a melt of higher Sr content. Texturally, different plagioclase types (e.g. zoned and inclusion-rich types) correspond to different degrees of overprint most likely caused by a thermal and compositional gradient in the boundary layer. The intrusion of a second mafic magma batch into the boundary layer is recorded by a thin An50 zone along plagioclase rims that crystallized from a melt enriched in Sr. Most probably, the second mafic intrusion caused disruption of the boundary layer, dispersal of the hybrid magma in the granite magma and formation of the enclaves. Rapid thermal quenching of the MMEs in the granite magma is manifested by An30 overgrowths on large plagioclase grains that contain needle apatites. Our results demonstrate the importance of microtextural investigations for the reconstruction of possible mixing end members in the formation of granites.

  13. Non-Covalent Interactions and Internal Dynamics in Pyridine-Ammonia a Combined Quantum-Chemical and Microwave Spectroscopy Study

    Science.gov (United States)

    Spada, Lorenzo; Tasinato, Nicola; Vazart, Fanny; Barone, Vincenzo; Caminati, Walther; Puzzarini, Cristina

    2017-06-01

    The 1:1 complex of ammonia with pyridine has been characterized by using state-of-the-art quantum-chemical computations combined with pulsed-jet Fourier-Transform microwave spectroscopy. The computed potential energy landscape pointed out the formation of a stable σ-type complex, which has been confirmed experimentally: the analysis of the rotational spectrum showed the presence of only one 1:1 pyridine - ammonia adduct. Each rotational transition is split into several components due to the internal rotation of NH_3 around its C_3 axis and to the hyperfine structure of both ^{14}N quadrupolar nuclei, thus providing the unequivocal proof that the two molecules form a σ-type complex involving both a N-H\\cdotsN and a C-H\\cdotsN hydrogen bond. The dissociation energy (BSSE and ZPE corrected) has been estimated to be 11.5 kJ\\cdotmol^{-1}. This work represents the first application of an accurate, yet efficient computational scheme, designed for the investigation of small biomolecules, to a molecular cluster.

  14. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography

    DEFF Research Database (Denmark)

    Franzen, Ulrik; Østergaard, Jesper

    2012-01-01

    Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary...... electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability...... of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization...

  15. Use of chemical and isotopic tracers to characterize the interactions between ground water and surface water in mantled karst

    Science.gov (United States)

    Katz, B.G.; Coplen, T.B.; Bullen, T.D.; Hal, Davis J.

    1997-01-01

    In the mantled karst terrane of northern Florida, the water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface. Chemical and isotopic analyses [18O/16O (??18O), 2H/1H (??D), 13C/12C (??13C), tritium(3H), and strontium-87/strontium-86(87Sr/86Sr)]along with geochemical mass-balance modeling were used to identify the dominant hydrochemical processes that control the composition of ground water as it evolves downgradient in two systems. In one system, surface water enters the Upper Floridan aquifer through a sinkhole located in the Northern Highlands physiographic unit. In the other system, surface water enters the aquifer through a sinkhole lake (Lake Bradford) in the Woodville Karst Plain. Differences in the composition of water isotopes (??18O and ??D) in rainfall, ground water, and surface water were used to develop mixing models of surface water (leakage of water to the Upper Floridan aquifer from a sinkhole lake and a sinkhole) and ground water. Using mass-balance calculations, based on differences in ??18O and ??D, the proportion of lake water that mixed with meteoric water ranged from 7 to 86% in water from wells located in close proximity to Lake Bradford. In deeper parts of the Upper Floridan aquifer, water enriched in 18O and D from five of 12 sampled municipal wells indicated that recharge from a sinkhole (1 to 24%) and surface water with an evaporated isotopic signature (2 to 32%) was mixing with ground water. The solute isotopes, ??13C and 87Sr/86Sr, were used to test the sensitivity of binary and ternary mixing models, and to estimate the amount of mass transfer of carbon and other dissolved species in geochemical reactions. In ground water downgradient from Lake Bradford, the dominant processes controlling carbon cycling in ground water were dissolution of carbonate minerals, aerobic degradation of organic matter, and hydrolysis of silicate minerals. In the deeper parts of the Upper

  16. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP: linking condensation, evaporation and chemical reactions of organics, oxidants and water

    Directory of Open Access Journals (Sweden)

    M. Shiraiwa

    2012-03-01

    Full Text Available We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007, and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds.

    In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative

  17. Classical ab initio van der Waals interactions from many-body dispersion and multipole machine learning models trained in chemical space

    CERN Document Server

    Bereau, Tristan; von Lilienfeld, O Anatole

    2015-01-01

    Accurate predictions of van der Waals forces require faithful models of dispersion, permanent and induced multipole-moments, as well as penetration and repulsion. We introduce a universal combined physics- and data-driven model of dispersion and multipole-moment contributions, respectively. Atomic multipoles are estimated "on-the-fly" for any organic molecule in any conformation using a machine learning approach trained on quantum chemistry results for tens of thousands of atoms in varying chemical environments drawn from thousands of organic molecules. Globally neutral, cationic, and anionic molecular charge states can be treated with individual models. Dispersion interactions are included via recently-proposed classical many-body potentials. For nearly one thousand intermolecular dimers, this approximate van der Waals model is found to reach an accuracy similar to that of state-of-the-art force fields, while bypassing the need for parametrization. Estimates of cohesive energies for the benzene crystal confi...

  18. Critical issues in benzene toxicity and metabolism: The effect of interactions with other organic chemicals on risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Medinsky, M.A.; Schlosser, P.M.; Bond, J.A. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1994-11-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene are well documented and include aplastic anemia and pancytopenia. Some individuals exposed repeatedly to cytotoxic concentrations of benzene develop acute myeloblastic anemia. It has been hypothesized that metabolism of benzene is required for its toxicity, although administration of no single benzene metabolite duplicates the toxicity of benzene. Several investigators have demonstrated that a combination of metabolites (hydroquinone and phenol, for example) is necessary to duplicate the hematotoxic effect of benzene. Enzymes implicated in the metabolic activation of benzene and its metabolites include the cytochrome P450 monooxygenases and myeloperoxidase. Since benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. Other organic molecules that are substrates for cytochrome P450 can inhibit the metabolism of benzene. For example, toluene has been shown to inhibit the oxidation of benzene in a noncompetitive manner. Enzyme inducers, such as ethanol, can alter the target tissue dosimetry of benzene metabolites by inducing enzymes responsible for oxidation reactions involved in benzene metabolism. 24 refs., 6 figs., 2 tabs.

  19. Toward high-throughput monitoring of metallodrug-protein interaction using capillary electrophoresis in chemically modified capillaries.

    Science.gov (United States)

    Shmykov, Alexei Y; Filippov, Vladimir N; Foteeva, Lidia S; Keppler, Bernhard K; Timerbaev, Andrei R

    2008-08-15

    The performance of capillary electrophoresis (CE) operating with a sulfonated capillary for the separation of protein adducts of anticancer ruthenium(III)-based drugs was evaluated. The coated capillary was shown to yield improved resolution of albumin- and transferrin-bound species of ruthenium compared with that attained with the bare fused-silica capillary. The coating also showed an increased reproducibility of migration times and peak areas and allowed reasonably high efficiency separation of analytes (up to 1300 theoretical plates per meter), which display high affinity toward a fused-silica surface. In addition, due to rather high electroosmotic flow (EOF, > 45 x 10(-5)cm(2)V(-1)s(-1)) in the coated capillary, it enabled fast counter-EOF monitoring of albumin and transferrin adducts. This benefit, together with requiring only a short flush with the background electrolyte to have migration times reproducible (at capillary holding promise for CE examination of fast reactions such as those accompanying protein-drug interactions and biotransformations associated with drug delivery via protein binding.

  20. Modelling of the interaction between chemical and mechanical behaviour of ion exchange resins incorporated into a cement-based matrix

    Directory of Open Access Journals (Sweden)

    Le Bescop P.

    2013-07-01

    Full Text Available In this paper, we present a predictive model, based on experimental data, to determine the macroscopic mechanical behavior of a material made up of ion exchange resins solidified into a CEM III cement paste. Some observations have shown that in some cases, a significant macroscopic expansion of this composite material may be expected, due to internal pressures generated in the resin. To build the model, we made the choice to break down the problem in two scale’s studies. The first deals with the mechanical behavior of the different heterogeneities of the composite, i.e. the resin and the cement paste. The second upscales the information from the heterogeneities to the Representative Elementary Volume (REV of the composite. The heterogeneities effects are taken into account in the REV by applying a homogenization method derived from the Eshelby theory combined with an interaction coefficient drawn from the poroelasticity theory. At the first scale, from the second thermodynamic law, a formulation is developed to estimate the resin microscopic swelling. The model response is illustrated on a simple example showing the impact of the calculated internal pressure, on the macroscopic strain.

  1. Two-Dimensional FTIR as a Tool to Study the Chemical Interactions within Cellulose-Ionic Liquid Solutions

    Directory of Open Access Journals (Sweden)

    Kalyani Kathirgamanathan

    2015-01-01

    Full Text Available In this study two-dimensional FTIR analysis was applied to understand the temperature effects on processing cellulose solutions in imidazolium-based ionic liquids. Analysis of the imidazolium ion νC2–H peak revealed hydrogen bonding within cellulose solutions to be dynamic on heating and cooling. The extent of hydrogen bonding was stronger on heating, consistent with greater ion mobility at higher temperature when the ionic liquid network structure is broken. At ambient temperatures a blue shifted νC2–H peak was indicative of greater cation-anion interactions, consistent with the ionic liquid network structure. Both cellulose and water further impact the extent of hydrogen bonding in these solutions. The FTIR spectral changes appeared gradual with temperature and contrast shear induced rheology changes which were observed on heating above 70°C and cooling below 40°C. The influence of cellulose on solution viscosity was not distinguished on initial heating as the ionic liquid network structure dominates rheology behaviour. On cooling, the quantity of cellulose has a greater influence on solution rheology. Outcomes suggest processing cellulose in ionic liquids above 40°C and to reduce the impacts of cation-anion effects and enhance solubilisation, processing should be done at 70°C.

  2. Study of interaction and adsorption of aromatic amines by manganese oxides and their role in chemical evolution

    Science.gov (United States)

    Bhushan, Brij; Nayak, Arunima; Kamaluddin

    2017-04-01

    The role of manganese oxides in concentrating organic moieties and offering catalytic activity for prebiotic reactions is investigated by studying their interaction with different aromatic amines such as aniline, p-chloroaniline, p-toluidine and p-anisidine. For all amines, metal oxides showed highest adsorption at neutral pH. The order of their adsorption capacity and affinity as revealed by the Langmuir constants was found to be manganosite (MnO) > bixbyite (Mn2O3) > hausmannite (Mn3O4) > and pyrolusite (MnO2). At alkaline pH, these manganese oxides offered their surfaces for oxidation of amines to form coloured oligomers. Analysis of the oxidation products by gas chromatography-mass spectrometry showed the formation of a dimer from p-anisidine and p-chloroaniline, while a trimer and tetramer is formed from p-toluidine and aniline, respectively. A reaction mechanism is proposed for the formation of the oligomers. While field-emission scanning electron microscopic studies confirm the binding phenomenon, the Fourier transform infrared spectroscopy analysis suggests that the mechanism of binding of amines on the manganese oxides was primarily electrostatic. The adsorption behaviour of the studied aromatic amines followed the order: p-anisidine > p-toluidine > aniline > p-chloroaniline, which is related to the basicities and structure of the amines. Our studies confirmed the significance of the role of manganese oxides in prebiotic chemistry.

  3. Chemical projectile-target interaction and liquid immiscibility in impact glass from the Wabar craters, Saudi Arabia

    Science.gov (United States)

    Hamann, Christopher; Hecht, Lutz; Ebert, Matthias; Wirth, Richard

    2013-11-01

    Impact glasses are usually strongly affected by secondary alteration and chemical weathering. Thus, in order to understand relevant formation processes, detailed petrographic studies on unweathered impact glasses are necessary as preserved heterogeneities in quenched impact glasses may serve as a tool to better understand their genesis. Here, we report on petrography and microchemistry of impact glasses from the Wabar impact craters (Saudi Arabia) that, with an age of ∼300 years, are among the youngest terrestrial impact craters. The fact that parts of the IIIAB iron meteorite have survived impact and subsequent weathering is granting Wabar a special role among the presently 184 confirmed terrestrial impact structures. Electron microprobe analysis (EMPA) and transmission electron microscopy (TEM) obtained on the black impact melt/glass variety at Wabar suggest that meteoritic Fe was selectively mixed with high-silica target melt at high temperatures due to selective oxidation, resulting in high Fe/Ni ratios for the black melt (37 on average, individual values range from 13 to 449) and low Fe/Ni ratios for projectile droplets ("FeNi spheres" with a Fe/Ni ratio of 3 on average; Fe/Ni ratio for the meteorite is ∼12). The black melt shows emulsion textures that are the result of silicate liquid immiscibility. Liquid-liquid phase-separation resulted in the formation of a poorly polymerized, ultrabasic melt (Lfe) rich in divalent cations like Fe2+, Ca2+, or Mg2+, that is dispersed in a highly polymerized, high-silica melt (Lsi) matrix. The typical Wabar black melt emulsion displays a spheres-in-a-matrix texture of ∼10-20% Lfe homogeneously dispersed in the form of two sets of spheres and droplets (10-30 nm and 0.1-0.4 μm in diameter) in ∼80-90% Lsi matrix, plus occasionally disseminated FeNi spheres. Around large (>10 μm) FeNi spheres, however, the typical emulsion texture changes to ∼21% Lsi dispersed in ∼79% Lfe. This change of texture is interpreted as

  4. Metallic fuels: The EBR-II legacy and recent advances

    Energy Technology Data Exchange (ETDEWEB)

    Douglas L. Porter; Steven L. Hayes; J. Rory Kennedy

    2012-09-01

    Experimental Breeder Reactor – II (EBR-II) metallic fuel was qualified for high burnup to approximately 10 atomic per cent. Subsequently, the electrometallurgical treatment of this fuel was demonstrated. Advanced metallic fuels are now investigated for increased performance, including ultra-high burnup and actinide burning. Advances include additives to mitigate the fuel/cladding chemical interaction and uranium alloys that combine Mo, Ti and Zr to improve alloy performance. The impacts of the advances—on fabrication, waste streams, electrorefining, etc.—are found to be minimal and beneficial. Owing to extensive research literature and computational methods, only a modest effort is required to complete their development.

  5. Chemical interaction of water molecules with framework Al in acid zeolites: a periodic ab initio study on H-clinoptilolite.

    Science.gov (United States)

    Valdiviés-Cruz, Karell; Lam, Anabel; Zicovich-Wilson, Claudio M

    2015-09-28

    Periodic quantum-chemistry methods as implemented in the CRYSTAL14 code were considered to analyse the interaction of acid clinoptilolite with water. Initially adsorbed molecules hydrolyse the Al-O bonds, giving rise to defective dealuminated materials. A suitable and representative periodic model of the partially disordered hydrated H-zeolite is the primitive cell (18 T sites) of a decahydrated trialuminated structure of HEU topology. The water distribution inside the material cavities was initially investigated. The model considered for further dealumination was the most stable one from those generated through a combined force field Monte Carlo and ab initio optimization strategy. Optimizations and energy estimations were made at the hybrid DFT level of theory (PBE0 functional) with an atomic basis set of VDZP quality. The energetics of the different pathways involved in the dealumination process was addressed by considering the Gibbs free energy with thermal and zero-point corrections through phonon analysis. It arises that hydrated models exhibit protonated water clusters stabilized by different kinds of H-bonds. The first Al extraction is slightly more energetically favourable from T3 than T2 sites, but at the same time the latter is more probable owing to its larger Al population. However, concerning the second dealumination step, it is more favourable removing the Al atom from both remaining sites after a starting abstraction from T2 rather than T3. These facts determine that the most probable overall pathways go through a first Al removal from T2. The agreement with experimental results is discussed.

  6. Modeling of the PWR fuel mechanical behaviour and particularly study of the pellet-cladding interaction in a fuel rod; Contribution a la modelisation du comportement mecanique des combustibles REP sous irradiation, avec en particulier le traitement de l`interaction pastille-gaine dans un crayon combustible

    Energy Technology Data Exchange (ETDEWEB)

    Hourdequin, N.

    1995-05-01

    In Pressurized Water Reactor (PWR) power plants, fuel cladding constitutes the first containment barrier against radioactive contamination. Computer codes, developed with the help of a large experimental knowledge, try to predict cladding failures which must be limited in order to maintain a maximal safety level. Until now, fuel rod design calculus with unidimensional codes were adequate to prevent cladding failures in standard PWR`s operating conditions. But now, the need of nuclear power plant availability increases. That leads to more constraining operating condition in which cladding failures are strongly influenced by the fuel rod mechanical behaviour, mainly at high power level. Then, the pellet-cladding interaction (PCI) becomes important, and is characterized by local effects which description expects a multidimensional modelization. This is the aim of the TOUTATIS 2D-3D code, that this thesis contributes to