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Sample records for pyrolytic carbons irradiated

  1. Temperature dependence of the thermal expansion of neutron-irradiated pyrolytic carbon and graphite

    International Nuclear Information System (INIS)

    Matsuo, Hideto

    1988-01-01

    The effects of neutron irradiation and annealing on the temperature dependence of the linear thermal expansion of pyrolytic carbon and graphite were investigated after irradiation at 930-1280 0 C to a maximum neutron fluence of 2.84 x 10 25 m -2 (E > 29 fJ). After irradiation, little change in the thermal expansion of pyrolytic graphite was observed. However, as-deposited pyrolytic carbon showed an increase in thermal expansion in the perpendicular direction, a decrease in the direction parallel to the deposition plane, and also an increase in the anisotropy of the thermal expansion. Annealing at 2000 0 C did not cause any effective changes for irradiated specimens of either as-deposited pyrolytic carbon or pyrolytic graphite. (author)

  2. Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very High Temperature Reactors

    International Nuclear Information System (INIS)

    Wang, Lumin; Was, Gary

    2010-01-01

    Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.

  3. Suspended 3D pyrolytic carbon microelectrodes for electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Keller, Stephan Sylvest

    2017-01-01

    with cyclic voltammetry (CV) and impedance spectroscopy (EIS) using potassium ferri-ferrocyanide redox probe in a custom made batch system with magnetic clamping. Different 3D pyrolytic carbon microelectrodes were compared and the optimal design displayed twice the peak current and half the charge transfer......Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes...... for electrochemical applications. A 3D polymer template in epoxy based photoresist (SU-8) was fabricated with multiple steps of UV photolithography and pyrolysed at 900 °C to obtain 3D carbon microelectrodes. The pyrolytic carbon microstructures were characterized by SEM, Raman spectroscopy and XPS to determine...

  4. Procedure for coating articles with pyrolytic carbon

    International Nuclear Information System (INIS)

    Adams, C.C.; Allen, C.L.; Besenbruch, G.E.A.

    1976-01-01

    A method to coat articles with pyrolytic carbon is described which is particularly suitable for small nuclear fuel particles as one obtains a very homogeneous layer. The pyrolytic carbon is produced according to the invention by decomposing a hydrocarbon gas mixture composed of an inert gas share (20-65 Vol%) and a mixture of acetylene and propylene. It is favourable to have the hydrocarbon mixture contain between 50 and 55 Vol% acetylene. Variations on the known procedure are given. The coating of spherical thorium dioxide particles is mentioned as an example. (UWI) [de

  5. Pyrolytic 3D Carbon Microelectrodes for Electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Amato, Letizia

    2016-01-01

    This work presents the fabrication and characterization of suspended three-dimensional (3D) pyrolytic carbon microelectrodes for electrochemical applications. For this purpose, an optimized process with multiple steps of UV photolithography with the negative tone photoresist SU-8 followed...... by pyrolysis at 900ºC for 1h was developed. With this process, microelectrode chips with a three electrode configuration were fabricated and characterized with cyclic voltammetry (CV) using a 10mM potassium ferri-ferrocyanide redox probe in a custom made batch system with magnetic clamping. The 3D pyrolytic...... carbon microelectrodes displayed twice the higher peak current compared to 2D....

  6. Erosion of CFC, pyrolytic and boronated graphite under short pulsed laser irradiation

    International Nuclear Information System (INIS)

    Kraaij, G.J.; Bakker, J.; Stad, R.C.L. van der

    1992-07-01

    The effect of short pulsed laser irradiation of '0/3' ms and up to 10 MJ/m 2 on different types of carbon base materials is described. These materials are investigated as candidate protection materials for the Plasma Facing Components of NET/ITER. These materials are: carbon fibre composite graphite, pyrolytic graphite and boronated graphite. The volume of the laser induced craters was measured with an optical topographic scanner, and these data are evaluated with a simple model for the erosion. As a results, the enthalpy of ablation is estimated as 30±3 MJ/kg. A comparison is made with finite element numerical calculations, and the effect of lateral heat transfer is estimated using an analytical model. (author). 8 refs., 23 figs., 4 tabs

  7. Early outcomes of pyrolytic carbon hemiarthroplasty for the treatment of trapezial-metacarpal arthritis

    NARCIS (Netherlands)

    Martinez de Aragon, J. S.; Moran, Steven L.; Rizzo, Marco; Reggin, Kirsten B.; Beckenbaugh, Robert D.

    2009-01-01

    PURPOSE: Pyrolytic carbon implants have been successfully used in the treatment of osteoarthritis of the metacarpophalangeal and proximal interphalangeal joints. Recently, pyrolytic carbon hemiarthroplasties have been proposed for the treatment of osteoarthritis of the trapezial-metacarpal (TM)

  8. Tailoring stress in pyrolytic carbon for fabrication of nanomechanical string resonators

    DEFF Research Database (Denmark)

    Quang, Long Nguyen; Larsen, Peter Emil; Boisen, Anja

    2018-01-01

    In order to achieve high resonance frequencies and quality factors of pyrolytic carbon MEMS string resonators the resonator material needs to have a large tensile stress. In this study, the influence of pyrolysis temperature, dwell time and ramping rate on the residual stress in thin pyrolytic...... carbon films is investigated with the bending plate method. The results show that the pyrolysis temperature is the most important parameter for tailoring the residual stress, with a transition from tensile stress at temperature below 800ºC to compressive stress at temperatures above 800ºC. Two kinds...... of photoresist: positive (AZ5214E) and negative (SU-8) and different pyrolysis conditions are used to fabricate pyrolytic carbon string resonators at variable pyrolysis conditions. The best performance is obtained for devices with a length of 400 µm fabricated at a pyrolysis temperature of 700ºC, ramping rate...

  9. Pyrolytic carbon coatings for nuclear fuels from commercial butane

    International Nuclear Information System (INIS)

    Abdelrazek, I.D.; Abdelhalim, A.S.

    1976-01-01

    Uranium dioxide and graphite semi-spherical particles (average diameter = 300 um) were coated with pyrolytic carbon at relatively low temperatures (800 to 1200 0 C). The spouting gas was a mixture of commercial butane and nitrogen. The hydrocarbon served as a source for carbon whereas nitrogenated as a diluent and a support for the bed. The total gas flow rate was 3.5 lit/min and the hydrocarbon content varied from 3 to 10%. Coating efficiencies ranging from 4 to 25 percent were obtained. The densities of the coatings varied from 1.25 g/cm 3 (which corresponds to coatings of laminar microstructures) and 1.82 g/cm 3 (which suggests the formation of isotropic coatings. Metallographic examination (using polarized light) of the pyrolytic carbon formed at the experimental conditions indicated the possibility of using the coatings for nuclear fuel applications

  10. Low-temperature preparation of pyrolytic carbon

    International Nuclear Information System (INIS)

    Kidd, R.W.; Seifert, D.A.; Browning, M.F.

    1984-01-01

    Previous studies have demonstrated that nuclear waste forms coated with chemical vapor deposited pyrolytic carbon (PyC) at about 1273 K can provide ground water leach protection. To minimize the release during coating of volatile material from the waste forms and permit the coating of waste forms with a low softening point, a study was initiated to develop parameters for the catalytic deposition of PyC at low temperatures. The parameters surveyed in a fluidized-bed coater were deposition temperatures, carbon precursors, catalyst, diluent gas, concentration, and pressure

  11. Improvement on the electrochemical characteristics of graphite anodes by coating of the pyrolytic carbon using tumbling chemical vapor deposition

    International Nuclear Information System (INIS)

    Han, Young-Soo; Lee, Jai-Young

    2003-01-01

    The electrochemical characteristics of graphite coated with pyrolytic carbon materials using tumbling chemical vapor deposition (CVD) process have been studied for the active material of anodes in lithium ion secondary batteries. Coating of pyrolytic carbons on the surface of graphite particles, which tumble in a rotating reactor tube, was performed through the pyrolysis of liquid propane gas (LPG). The surface morphology of these graphite particles coated with pyrolytic carbon has been observed with scanning electron microscopy (SEM). The surface of graphite particles can well be covered with pyrolytic carbon by tumbling CVD. High-resolution transmission electron microscopy (HRTEM) image of these carbon particles shows that the core part is highly ordered carbon, while the shell part is disordered carbon. We have found that the new-type carbon obtained from tumbling CVD has a uniform core (graphite)-shell (pyrolytic carbon) structure. The electrochemical property of the new-type carbons has been examined using a charge-discharge cycler. The coating of pyrolytic carbon on the surface of graphite can effectively reduce the initial irreversible capacity by 47.5%. Cyclability and rate-capability of theses carbons with the core-shell structure are much better than those of bare graphite. From electrochemical impedance spectroscopy (EIS) spectra, it is found that the coating of pyrolytic carbon on the surface of graphite causes the decrease of the contact resistance in the carbon electrodes, which means the formation of solid electrolyte interface (SEI) layer is suppressed. We suggest that coating of pyrolytic carbon by the tumbling CVD is an effective method in improving the electrochemical properties of graphite electrodes for lithium ion secondary batteries

  12. Sealing nuclear graphite with pyrolytic carbon

    International Nuclear Information System (INIS)

    Feng, Shanglei; Xu, Li; Li, Li; Bai, Shuo; Yang, Xinmei; Zhou, Xingtai

    2013-01-01

    Pyrolytic carbon (PyC) coatings were deposited on IG-110 nuclear graphite by thermal decomposition of methane at ∼1830 °C. The PyC coatings are anisotropic and airtight enough to protect IG-110 nuclear graphite against the permeation of molten fluoride salts and the diffusion of gases. The investigations indicate that the sealing nuclear graphite with PyC coating is a promising method for its application in Molten Salt Reactor (MSR)

  13. Contribution to the study of hard, low-density pyrolytic carbons

    International Nuclear Information System (INIS)

    Boutin, F.R.

    1966-06-01

    Apparent contradictions in the properties of pyrolytic carbons obtained at 1600 deg C (hardness and graphitization) are studied. It is shown that structure of the deposit is turbostratic with high internal stresses (δ -2 ), and it graphitizes (by thermal treatment over 2000 deg C) in a similar manner to graphitisable carbon. Because the deposit forms lamellar compounds, it is presumed that the structure is similar to that of graphitisable carbon. Since it is not structure dependant, the hardness originates from the 'growth texture' and is not comparable with the hardness of a non-graphitisable carbon. The pyrolytic carbon studied is composed of regions, on the overage a few microns across, formed by the stacking of small carbon platelets, interlocked and showing a preferred orientation. The mis-orientation of the various regions produces general disorientation. We estimate that the introduction of the particles of some material such as thermal black which are observed in the electron microscope are responsible for the mis-orientation. The density and hardness of the deposit are a result of the interlocking of platelets, which creates a closed porosity and prevents any sliding of the atomic planes. (author) [fr

  14. Design and Thermal Analysis for Irradiation of Pyrolytic Carbon/Silicon Carbide Diffusion Couples in the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gerczak, Tyler J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Kurt R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Petrie, Christian M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    Tristructural-isotropic (TRISO)–coated particle fuel is a promising advanced fuel concept consisting of a spherical fuel kernel made of uranium oxide and uranium carbide, surrounded by a porous carbonaceous buffer layer and successive layers of dense inner pyrolytic carbon (IPyC), silicon carbide (SiC) deposited by chemical vapor , and dense outer pyrolytic carbon (OPyC). This fuel concept is being considered for advanced reactor applications such as high temperature gas-cooled reactors (HTGRs) and molten salt reactors (MSRs), as well as for accident-tolerant fuel for light water reactors (LWRs). Development and implementation of TRISO fuel for these reactor concepts support the US Department of Energy (DOE) Office of Nuclear Energy mission to promote safe, reliable nuclear energy that is sustainable and environmentally friendly. During operation, the SiC layer serves as the primary barrier to metallic fission products and actinides not retained in the kernel. It has been observed that certain fission products are released from TRISO fuel during operation, notably, Ag, Eu, and Sr [1]. Release of these radioisotopes causes safety and maintenance concerns.

  15. Effects of Processing Parameters on the Density and Microstructure of Pyrolytic Carbon

    International Nuclear Information System (INIS)

    Kim, Weon Ju; Park, Jeong Nam; Park, Jong Hoon; Cho, Moon Sung; Lee, Young Woo; Park, Ji Yeon

    2007-01-01

    Chemical vapor deposition (CVD) of pyrolytic carbon (PyC) and silicon carbide (SiC) has been applied to TRISO-coated fuel particles for high-temperature gas-cooled reactors (HTGR). The porous PyC coating layer, called the buffer layer, attenuates fission recoils and provides void volume for gaseous fission products and carbon monoxide. The inner PyC layer acts as a containment to gaseous products. The outer PyC layer protects the SiC coating layer by inducing a compressive stress and provides chemical compatibility with a graphite matrix in the fuel compact. The PyC layers undergo shrinkage due to neutron irradiation, affecting the design and modeling of fuel particles. Because the dimensional change of PyC depends on the detailed microstructure of PyC, it differs from one fabrication route to another one. This requires a new design of irradiation experiment applicable to spherical objects and leads to an international collaborative work called PYCASSO (PYrocarbon irradiation for Creep And Swelling/Shrinkage of Objects). KAERI proposed four different types of PyC layers coated on ZrO 2 particles, buffer with a density of 1.0 and dense PyCs with densities of 1.7, 1.9 and 2.1 g/cm 3 , for the irradiation experiment. In this study, we fabricated PyC-coated particles with various coating densities for supporting the PYCASSO experiment. We also investigated effects of processing parameters such as temperature, hydrocarbon concentration and gas flow rate on the density and microstructure of the PyC layer

  16. Mechanical performance of pyrolytic carbon in prosthetic heart valve applications.

    Science.gov (United States)

    Cao, H

    1996-06-01

    An experimental procedure has been developed for rigorous characterization of the fracture resistance and fatigue crack extension in pyrolytic carbon for prosthetic heart valve application. Experiments were conducted under sustained and cyclic loading in a simulated biological environment using Carbomedics Pyrolite carbon. While the material was shown to have modest fracture toughness, it exhibited excellent resistance to subcritical crack growth. The crack growth kinetics in pyrolytic carbon were formulated using a phenomenological description. A fatigue threshold was observed below which the crack growth rate diminishes. A damage tolerance concept based on fracture mechanics was used to develop an engineering design approach for mechanical heart valve prostheses. In particular, a new quantity, referred to as the safe-life index, was introduced to assess the design adequacy against subcritical crack growth in brittle materials. In addition, a weakest-link statistical description of the fracture strength is provided and used in the design of component proof-tests. It is shown that the structural reliability of mechanical heart valves can be assured by combining effective flaw detection and manufacturing quality control with adequate damage tolerance design.

  17. Cathode deposits in fullerene formation — microstructural evidence for independent pathways of pyrolytic carbon and nanobody formation

    Science.gov (United States)

    Taylor, G. H.; Gerald, J. D. Fitz; Pang, L.; Wilson, M. A.

    1994-01-01

    Microstructures in cathode deposits formed during fullerene production by electrical arcing in helium have been examined in detail. This has provided new information about the mechanisms by which nanobodies (nanotubes and nanoparticles) and pyrolytic carbon are deposited. Nanobodies and pyrolytic carbon form independently; the former probably grow in the plasma then deposit on the electrode but much of the latter deposits directly on the electrode surface.

  18. Nanomechanical Pyrolytic Carbon Resonators: Novel Fabrication Method and Characterization of Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Maksymilian Kurek

    2016-07-01

    Full Text Available Micro- and nanomechanical string resonators, which essentially are highly stressed bridges, are of particular interest for micro- and nanomechanical sensing because they exhibit resonant behavior with exceptionally high quality factors. Here, we fabricated and characterized nanomechanical pyrolytic carbon resonators (strings and cantilevers obtained through pyrolysis of photoresist precursors. The developed fabrication process consists of only three processing steps: photolithography, dry etching and pyrolysis. Two different fabrication strategies with two different photoresists, namely SU-8 2005 (negative and AZ 5214e (positive, were compared. The resonant behavior of the pyrolytic resonators was characterized at room temperature and in high vacuum using a laser Doppler vibrometer. The experimental data was used to estimate the Young’s modulus of pyrolytic carbon and the tensile stress in the string resonators. The Young’s moduli were calculated to be 74 ± 8 GPa with SU-8 and 115 ± 8 GPa with AZ 5214e as the precursor. The tensile stress in the string resonators was 33 ± 7 MPa with AZ 5214e as the precursor. The string resonators displayed maximal quality factor values of up to 3000 for 525-µm-long structures.

  19. Investigation on the recombination kinetics of the pyrolytic free-radicals in the irradiated polyimide

    International Nuclear Information System (INIS)

    Sun Chengyue; Wu Yiyong; Yue Long; Shi Yaping; Xiao Jingdong

    2012-01-01

    Highlights: ► Free radicals behavior was exposure during the irradiation and anneal during the post storage. ► Both of the recombination and oxygen reaction affect the post-annealing evolution of free radicals. ► The activation energy and the surface reaction rate were calculated by the analysis of the free radical anneal process. - Abstract: The free radical behavior of 60 and 110 keV proton-irradiated polyimide were investigated using electron paramagnetic resonance measurements. The results indicate that during proton irradiation, a type of pyrolytic carbon free radical was formed with a g value of 2.0025. The radical population was found, after proton irradiation to decrease in a combination of an exponential and linear modes with an annealing time in the range of 50–120 °C. The exponential part indicated a radical recombination process while the linear part is due to the reaction of the radical with the ambient. Using the annealing results, the recombination activation energy of the radicals was determined as 12.4 ± 0.2 and 17.6 ± 0.2 kJ/mol for 60 and 110 keV irradiated polyimide, respectively, with a surface reaction rate of about 0.02/h. It is possible that the kinetic study presented here is used as one of the criteria for predicting the optical properties of polyimide material in spacecraft. The mechanism of the free radical evolution will be discussed in this paper.

  20. Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications

    International Nuclear Information System (INIS)

    Behzadi, Shahed; Simchi, Abdolreza; Imani, Mohammad; Yousefi, Mohammad; Galinetto, Pietro; Amiri, Houshang; Stroeve, Pieter; Mahmoudi, Morteza

    2012-01-01

    Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses. (paper)

  1. Pyrolytic carbon membranes containing silica: morphological approach on gas transport behavior

    Science.gov (United States)

    Park, Ho Bum; Lee, Sun Yong; Lee, Young Moo

    2005-04-01

    Pyrolytic carbon membrane containing silica (C-SiO 2) is a new-class material for gas separation, and in the present work we will deal with it in view of the morphological changes arising from the difference in the molecular structure of the polymeric precursors. The silica embedded carbon membranes were fabricated by a predetermined pyrolysis step using imide-siloxane copolymers (PISs) that was synthesized from benzophenone tetracarboxylic dianhydrides (BTDA), 4,4'-oxydianiline (ODA), and amine-terminated polydimethylsiloxane (PDMS). To induce different morphologies at the same chemical composition, the copolymers were prepared using one-step (preferentially a random segmented copolymer) sand two-step polymerization (a block segmented copolymer) methods. The polymeric precursors and their pyrolytic C-SiO 2 membranes were analyzed using thermal analysis, atomic force microscopy, and transmission electron microscopy, etc. It was found that the C-SiO 2 membrane derived from the random PIS copolymer showed a micro-structure containing small well-dispersed silica domains, whereas the C-SiO 2 membrane from the block PIS copolymer exhibited a micro-structure containing large silica domains in the continuous carbon matrix. Eventually, the gas transport through these C-SiO 2 membranes was significantly affected by the morphological changes of the polymeric precursors.

  2. Upgrading pyrolytic residue from waste tires to commercial carbon black.

    Science.gov (United States)

    Zhang, Xue; Li, Hengxiang; Cao, Qing; Jin, Li'e; Wang, Fumeng

    2018-05-01

    The managing and recycling of waste tires has become a worldwide environmental challenge. Among the different disposal methods for waste tires, pyrolysis is regarded as a promising route. How to effectively enhance the added value of pyrolytic residue (PR) from waste tires is a matter of great concern. In this study, the PRs were treated with hydrochloric and hydrofluoric acids in turn under ultrasonic waves. The removal efficiency for the ash and sulfur was investigated. The pyrolytic carbon black (PCB) obtained after treating PR with acids was analyzed by X-ray fluorescence spectrophotometry, Fourier transform infrared spectrometry, X-ray diffractometry, laser Raman spectrometry, scanning electron microscopy, thermogravimetric (TG) analysis, and physisorption apparatus. The properties of PCB were compared with those of commercial carbon black (CCB) N326 and N339. Results showed PRs from waste tires were mainly composed of carbon, sulfur, and ash. The carbon in PCB was mainly from the CCB added during tire manufacture rather than from the pyrolysis of pure rubbers. The removal percentages for the ash and sulfur of PR are 98.33% (from 13.98 wt % down to 0.24 wt %) and 70.16% (from 1.81 wt % down to 0.54 wt %), respectively, in the entire process. The ash was mainly composed of metal oxides, sulfides, and silica. The surface properties, porosity, and morphology of the PCB were all close to those of N326. Therefore, PCB will be a potential alternative of N326 and reused in tire manufacture. This route successfully upgrades PR from waste tires to the high value-added CCB and greatly increases the overall efficiency of the waste tire pyrolysis industry.

  3. Swift heavy ions induced irradiation effects in monolayer graphene and highly oriented pyrolytic graphite

    International Nuclear Information System (INIS)

    Zeng, J.; Yao, H.J.; Zhang, S.X.; Zhai, P.F.; Duan, J.L.; Sun, Y.M.; Li, G.P.; Liu, J.

    2014-01-01

    Monolayer graphene and highly oriented pyrolytic graphite (HOPG) were irradiated by swift heavy ions ( 209 Bi and 112 Sn) with the fluence between 10 11 and 10 14 ions/cm 2 . Both pristine and irradiated samples were investigated by Raman spectroscopy. It was found that D and D′ peaks appear after irradiation, which indicated the ion irradiation introduced damage both in the graphene and graphite lattice. Due to the special single atomic layer structure of graphene, the irradiation fluence threshold Φ th of the D band of graphene is significantly lower ( 11 ions/cm 2 ) than that (2.5 × 10 12 ions/cm 2 ) of HOPG. The larger defect density in graphene than in HOPG indicates that the monolayer graphene is much easier to be damaged than bulk graphite by swift heavy ions. Moreover, different defect types in graphene and HOPG were detected by the different values of I D /I D′ . For the irradiation with the same electronic energy loss, the velocity effect was found in HOPG. However, in this experiment, the velocity effect was not observed in graphene samples irradiated by swift heavy ions

  4. Erosion of pyrolytic graphite and Ti-doped graphite due to high flux irradiation

    International Nuclear Information System (INIS)

    Ohtsuka, Yusuke; Ohashi, Junpei; Ueda, Yoshio; Isobe, Michiro; Nishikawa, Masahiro

    1997-01-01

    The erosion of pyrolytic graphite and titanium doped graphite RG-Ti above 1,780 K was investigated by 5 keV Ar beam irradiation with the flux from 4x10 19 to 1x10 21 m -2 ·s -1 . The total erosion yields were significantly reduced with the flux. This reduction would be attributed to the reduction of RES (radiation enhanced sublimation) yield, which was observed in the case of isotropic graphite with the flux dependence of RES yield of φ -0.26 (φ: flux) obtained in our previous work. The yield of pyrolytic graphite was roughly 30% higher than that of isotropic graphite below the flux of 10 20 m -2 ·s -1 whereas each yield approached to very close value at the highest flux of 1x10 21 m -2 ·s -1 . This result indicated that the effect of graphite structure on the RES yield, which was apparent in the low flux region, would disappear in the high flux region probably due to the disordering of crystal structure. In the case of irradiation to RG-Ti at 1,780 K, the surface undulations evolved with a mean height of about 3 μm at 1.2x10 20 m -2 ·s -1 , while at higher flux of 8.0x10 20 m -2 ·s -1 they were unrecognizable. These phenomena can be explained by the reduction of RES of graphite parts excluding TiC grains. (author)

  5. Pyrolytic Carbon Nanosheets for Ultrafast and Ultrastable Sodium-Ion Storage.

    Science.gov (United States)

    Cho, Se Youn; Kang, Minjee; Choi, Jaewon; Lee, Min Eui; Yoon, Hyeon Ji; Kim, Hae Jin; Leal, Cecilia; Lee, Sungho; Jin, Hyoung-Joon; Yun, Young Soo

    2018-04-01

    Na-ion cointercalation in the graphite host structure in a glyme-based electrolyte represents a new possibility for using carbon-based materials (CMs) as anodes for Na-ion storage. However, local microstructures and nanoscale morphological features in CMs affect their electrochemical performances; they require intensive studies to achieve high levels of Na-ion storage performances. Here, pyrolytic carbon nanosheets (PCNs) composed of multitudinous graphitic nanocrystals are prepared from renewable bioresources by heating. In particular, PCN-2800 prepared by heating at 2800 °C has a distinctive sp 2 carbon bonding nature, crystalline domain size of ≈44.2 Å, and high electrical conductivity of ≈320 S cm -1 , presenting significantly high rate capability at 600 C (60 A g -1 ) and stable cycling behaviors over 40 000 cycles as an anode for Na-ion storage. The results of this study show the unusual graphitization behaviors of a char-type carbon precursor and exceptionally high rate and cycling performances of the resulting graphitic material, PCN-2800, even surpassing those of supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Alternative waste form development - low-temperature pyrolytic carbon coatings

    International Nuclear Information System (INIS)

    Oma, K.H.; Rusin, J.M.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Although several chemical vapor deposition (CVD) - coated waste forms have been successfully produced, some major disadvantages associated with the high-temperature fluidized-bed CVD coating process exist. To overcome these disadvantages, the Pacific Northwest Laboratory has initiated the development of a pyrolytic carbon CVD coating system to coat large waste-form particles at temperatures ranging from 400 to 500/degree/C. This relatively simple system has been used to coat kilogram quantities of simulated waste-glass marbles. Further development of this system could result in a viable process to coat bulk quantities of both glass and ceramic waste forms. This paper discusses various aspects of the development work, including coating techniques, parametric study, and coater equipment. 10 refs

  7. Structure-property relations for silicon nitride matrix composites reinforced with pyrolytic carbon pre-coated Hi-Nicalon fibers

    NARCIS (Netherlands)

    Kooi, B.J.; Hosson, J.Th.M. De; Olivier, C.; Veyret, J.B.

    1999-01-01

    Si3N4 matrix composites reinforced with pyrolytic carbon pre-coated Hi-Nicalon (SiC) fibers, were studied using tensile testing and transmission electron microscopy. Three types of samples were evaluated all with a nominal coating thickness of 200 nm. The composites were densified by hot pressing at

  8. Effect of filling surface-treated pyrolytic char on resistivity of rubber films

    Directory of Open Access Journals (Sweden)

    Pattraporn Yamkaya

    2015-03-01

    Full Text Available In this research, natural rubber (NR films filled with pyrolytic tire char, carbon black N234 and N330 were compared for their electrical resistivity. The filler loading was varied to be 5, 10, 15, 20 and 25% of dry rubber content. The effect of surfactant which is 2 %w/v sodium dodecyl sulfate (SDS was also investigated. In the experiments, it was necessary to disperse the pyrolytic char in ethyl alcohol while disperse carbon black (CB in ammonium hydroxide solution prior to mixing with the rubber latex and the filled NR film was prepared by casting the mixture on a plate. It was found that increasing the amount of pyrolytic char in the NR film could lower its resistivity. The surfactant, SDS, could help better dispersion of both CB and pyrolytic char, thereby decreasing the resistivity. In a separate experiment where hexane vapor was absorbed in NR film without surfactant, in the first 30 seconds, the rate of increasing resistivity of the CB-filled film was not seen as clearly as that of pyrolytic-char-filled film. For the films with surfactant, the slow increase in resistivity of the NR films filled with N330 and pyrolytic char during adsorbing hexane vapor was observed.

  9. Thermal desorption spectroscopy of pyrolytic graphite cleavage faces after keV deuterium irradiation at 330-1000 K

    International Nuclear Information System (INIS)

    Gotoh, Y.; Yamaki, T.; Tokiguchi, K.

    1992-01-01

    Thermal desorption spectroscopy (TDS) measurements were made on D 2 and CD 4 from surface layers of pyrolytic graphite cleavage faces after 3 keV D + 3 irradiation to 1.5 x 10 18 D/cm 2 at irradiation temperatures from 330 to 1000 K. Thermal desorption of both D 2 and CD 4 was observed to rise simultaneously at around 700 K. The D 2 peak was found at T m = 900-1000 K, while the CD 4 peak appeared at a lower temperature, 800-840 K. The T m for the D 2 TDS increased, while that for the CD 4 decreased with increasing irradiation temperature. These results obviously indicate that the D 2 desorption is detrapping/recombination limited, while the CD 4 desorption is most likely to be diffusion limited. The amount of thermally desorbed D 2 after the D + irradiation was observed to monotonously decrease as the irradiation temperature was increased from 330 to 1000 K. These tendencies agreed with previous results for the irradiation temperature dependencies of both C1s chemical shift (XPS) and the interlayer spacing, d 002 (HRTEM), on the graphite basal face. (orig.)

  10. On the fractography of overload, stress corrosion, and cyclic fatigue failures in pyrolytic-carbon materials used in prosthetic heart-valve devices.

    Science.gov (United States)

    Ritchie, R O; Dauskardt, R H; Pennisi, F J

    1992-01-01

    A scanning electron microscopy study is reported of the nature and morphology of fracture surfaces in pyrocarbons commonly used for the manufacture of mechanical heart-valve prostheses. Specifically, silicon-alloyed low-temperature-isotropic (LTI)-pyrolytic carbon is examined, both as a coating on graphite and as a monolithic material, following overload, stress corrosion (static fatigue), and cyclic fatigue failures in a simulated physiological environment of 37 degrees C Ringer's solution. It is found that, in contrast to most metallic materials yet in keeping with many ceramics, there are no distinct fracture morphologies in pyro-carbons which are characteristic of a specific mode of loading; fracture surfaces appear to be identical for both catastrophic and subcritical crack growth under either sustained or cyclic loading. We conclude that caution should be used in assigning the likely cause of failure of pyrolytic carbon heart-valve components using fractographic examination.

  11. Irradiation test HT-31: high-temperature irradiation behavior of LASL-made extruded fuel rods and LASL-made coated particles

    International Nuclear Information System (INIS)

    Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; Davidson, K.V.; Schell, D.H.

    1977-04-01

    Three LASL-made extruded graphite and coated particle fuel rods have been irradiated in the Oak Ridge National Laboratory High Fluence Isotope Reactor test HT-31. Test conditions were about 9 x 10 21 nvt(E > .18 MeV) at 1250 0 C. The graphite matrix showed little or no effect of the irradiation. LASL-made ZrC containing coated particles with ZrC coats and ZrC-doped pyrolytic carbon coats showed no observable effects of the irradiation

  12. Erosion of pyrolytic carbon under high surface energy deposition from a pulsed hydrogen plasma

    International Nuclear Information System (INIS)

    Bolt, H.

    1992-01-01

    Carbon materials are widely applied as plasma facing materials in nuclear fusion devices and are also the prime candidate materials for the next generation of experimental fusion reactors. During operation these materials are frequently subjected to high energy deposition from plasma disruptions. The erosion of carbon materials is regarded as the main issue governing the operational lifetime of plasma facing components. Laboratory experiments have been performed to study the thermal erosion behaviour of carbon in a plasma environment. In the experiments the surface of pyrolytic carbon specimens was exposed to pulsed energy deposition of up to 3.8 MJ m -2 from a hydrogen plasma. The behaviour of the eroded carbon species in the plasma was measured by time-resolved and space-resolved spectroscopy. Intense line radiation of ionic carbon has been measured in the plasma in front of the carbon surface. The results show that the eroded carbon is immediately ionised in the vicinity of the material surface, with a fraction of it being ionised to the double-charged state. (Author)

  13. Deposition of pyrolytic carbon from C2H2--C3H6--Ar gas mixtures: coating under adiabatic conditions

    International Nuclear Information System (INIS)

    Gyarmati, E.; Gupta, A.K.; Puetter, B.

    In this report a method is described by which pyrolytic carbon can be deposited from ethylene-propylene-argon gas mixtures at temperatures between 1230 and 1330 0 C in 55-mm fluidized bed apparatus without heat exchange with the apparatus

  14. Interaction of noble-metal fission products with pyrolytic silicon carbide

    International Nuclear Information System (INIS)

    Lauf, R.J.; Braski, D.N.

    1982-01-01

    Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-SiC interactions, particles of UO 2 or UC 2 are doped with fission product elements before coating and are then held in a thermal gradient up to several thousand hours. Examination of the SiC coatings by TEM-AEM after annealing shows that silver behaves differently from the palladium group

  15. Study of nanometric thin pyrolytic carbon films for explosive electron emission cathode in high-voltage planar diode

    Energy Technology Data Exchange (ETDEWEB)

    Baryshevsky, Vladimir; Belous, Nikolai; Gurinovich, Alexandra; Gurnevich, Evgeny [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Kuzhir, Polina, E-mail: polina.kuzhir@gmail.com [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Maksimenko, Sergey [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); National Research Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation); Molchanov, Pavel; Shuba, Mikhail [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya Str. 11, Minsk 220030 (Belarus); Roddatis, Vladimir [CIC energiGUNE, Albert Einstein 48, 01510 Minano, Alava (Spain); Institut für Materialphysik of Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Kaplas, Tommi; Svirko, Yuri [Institute of Photonics, University of Eastern Finland, P.O. Box 111, Joensuu FI-80101 (Finland)

    2015-04-30

    We report on an experimental study of explosive electron emission properties of cathode made by nanometric thin pyrolytic carbon (PyC) films (2–150 nm) deposited on Cu substrate via methane-based chemical vapor deposition. High current density at level of 300 A/cm{sup 2} in 5 · 10{sup −5} Pa vacuum has been observed together with very stable explosive emission from the planar cathode. The Raman spectroscopy investigation proves that the PyC films remain the same after seven shots. According to the optical image analysis of the cathode before and after one and seven shots, we conclude that the most unusual and interesting feature of using the PyC films/Cu cathode for explosive emission is that the PyC layer on the top of the copper target prevents its evaporation and oxidation, which leads to higher emission stability compared to conventional graphitic/Cu cathodes, and therefore results in longer working life. - Highlights: • Explosive electron emission from pyrolytic carbon (PyC) cathode is reported. • We observe high current density, 300 A/cm{sup 2}, and stable emission parameters. • PyC integrity ensures a high application potential for high current electronics.

  16. DEPOSITION AND PROPERTIES OF A LITTLE-ORIENTED PYROLYTIC CARBON; Deposition et proprietes d'un carbone pyrolytique peu oriente

    Energy Technology Data Exchange (ETDEWEB)

    Rappeneau, J; Bocquet, M; Yvars, M; David, C; Auriol, A

    1963-06-15

    Pyrolytic carbon obtained by thermal decomposition of acetylene, at partial pressures of 0.02 to 0.1 atm, on walls heated to between 1550 and 1650 deg C, is characterized by its low density (1.35) and a not very marked preferred orientation of the crystallites. The latter property is expressed by an absence of laminar structure in the deposit and by its good compatibility with an artiticial graphite substrate. Following a description of the method of deposition and an outline of the structural properties, certain physical and chemical properties of the substance are examined. (auth)

  17. Adsorption and manipulation of carbon onions on highly oriented pyrolytic graphite studied with atomic force microscopy

    International Nuclear Information System (INIS)

    Zhou Jianfeng; Shen Ziyong; Hou Shimin; Zhao Xingyu; Xue Zengquan; Shi Zujin; Gu Zhennan

    2007-01-01

    Carbon onions produced by DC arc discharge method were deposited on highly oriented pyrolytic graphite (HOPG) surface and their adsorption and manipulation was studied using an atomic force microscopy (AFM). Well-dispersed adsorption of carbon onions on HOPG surface was obtained and aggregations of onions were not observed. The van der Waals interaction between the onion and HOPG surface and that between two onions, were calculated and discussed using Hamaker's theory. The manipulation of adsorbed onions on HOPG surface was realized using the AFM in both the raster mode and the vector mode. The controllability and precision of two manipulation modes were compared and the vector mode manipulation was found superior, and is a useful technique for the construction of nano-scale devices based on carbon onions

  18. Cyclic fatigue and fracture in pyrolytic carbon-coated graphite mechanical heart-valve prostheses: role of small cracks in life prediction.

    Science.gov (United States)

    Dauskardt, R H; Ritchie, R O; Takemoto, J K; Brendzel, A M

    1994-07-01

    A fracture-mechanics based study has performed to characterize the fracture toughness and rates of cyclic fatigue-crack growth of incipient flaws in prosthetic heart-valve components made of pyrolytic carbon-coated graphite. Such data are required to predict the safe structural lifetime of mechanical heart-valve prostheses using damage-tolerant analysis. Unlike previous studies where fatigue-crack propagation data were obtained using through-thickness, long cracks (approximately 2-20 mm long), growing in conventional (e.g., compact-tension) samples, experiments were performed on physically small cracks (approximately 100-600 microns long), initiated on the surface of the pyrolytic-carbon coating to simulate reality. Small-crack toughness results were found to agree closely with those measured conventionally with long cracks. However, similar to well-known observations in metal fatigue, it was found that based on the usual computations of the applied (far-field) driving force in terms of the maximum stress intensity, Kmax, small fatigue cracks grew at rates that exceeded those of long cracks at the same applied stress intensity, and displayed a negative dependency on Kmax; moreover, they grew at applied stress intensities less than the fatigue threshold value, below which long cracks are presumed dormant. To resolve this apparent discrepancy, it is shown that long and small crack results can be normalized, provided growth rates are characterized in terms of the total (near-tip) stress intensity (incorporating, for example, the effect of residual stress); with this achieved, in principle, either form of data can be used for life prediction of implant devices. Inspection of the long and small crack results reveals extensive scatter inherent in both forms of growth-rate data for the pyrolytic-carbon material.

  19. Adsorption of Pb(II by Activated Pyrolytic Char from Used Tire

    Directory of Open Access Journals (Sweden)

    Lu Ping

    2016-01-01

    Full Text Available As a renewable resource, the pyrolytic char derived from used tire has promising adsorption capacities owing to its similar structure and properties with active carbon. The purification and activation of the pyrolytic char from used tire, as well as the application of this material in the adsorption of Pb(II in water is conducted. The influences on the adsorption capacity by temperature and pH value are investigated and discussed; the adsorption thermodynamics and kinetics are also studied. The results show that the pyrolytic char from used tire has remarkable adsorption capacity for Pb(II, and the adsorption is an endothermic process complying with the Langmuir isotherm. The adsorption kinetics is a pseudo second-order reaction.

  20. Pyrolytic carbon-coated stainless steel felt as a high-performance anode for bioelectrochemical systems.

    Science.gov (United States)

    Guo, Kun; Hidalgo, Diana; Tommasi, Tonia; Rabaey, Korneel

    2016-07-01

    Scale up of bioelectrochemical systems (BESs) requires highly conductive, biocompatible and stable electrodes. Here we present pyrolytic carbon-coated stainless steel felt (C-SS felt) as a high-performance and scalable anode. The electrode is created by generating a carbon layer on stainless steel felt (SS felt) via a multi-step deposition process involving α-d-glucose impregnation, caramelization, and pyrolysis. Physicochemical characterizations of the surface elucidate that a thin (20±5μm) and homogenous layer of polycrystalline graphitic carbon was obtained on SS felt surface after modification. The carbon coating significantly increases the biocompatibility, enabling robust electroactive biofilm formation. The C-SS felt electrodes reach current densities (jmax) of 3.65±0.14mA/cm(2) within 7days of operation, which is 11 times higher than plain SS felt electrodes (0.30±0.04mA/cm(2)). The excellent biocompatibility, high specific surface area, high conductivity, good mechanical strength, and low cost make C-SS felt a promising electrode for BESs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Bio-compatibility of the surface layer of pyrolytic graphite

    Czech Academy of Sciences Publication Activity Database

    Starý, V.; Bačáková, Lucie; Horník, J.; Chmelík, V.

    2003-01-01

    Roč. 433, 1-2 (2003), s. 191-198 ISSN 0040-6090 R&D Projects: GA ČR GA106/99/0626; GA MŠk OC 527.130 Institutional research plan: CEZ:AV0Z5011922; CEZ:MSM 210000012 Keywords : carbon-carbon composite * pyrolytic graphite * cell adhesion Subject RIV: JI - Composite Materials Impact factor: 1.598, year: 2003

  2. Small-angle neutron scattering and cyclic voltammetry study on electrochemically oxidized and reduced pyrolytic carbon

    International Nuclear Information System (INIS)

    Braun, A.; Kohlbrecher, J.; Baertsch, M.; Schnyder, B.; Koetz, R.; Haas, O.; Wokaun, A.

    2004-01-01

    The electrochemical double layer capacitance and internal surface area of a pyrolytic carbon material after electrochemical oxidation and subsequent reduction was studied with cyclic voltammetry and small-angle neutron scattering. Oxidation yields an enhanced internal surface area (activation), and subsequent reduction causes a decrease of this internal surface area. The change of the Porod constant, as obtained from small-angle neutron scattering, reveals that the decrease in internal surface area is not caused merely by a closing or narrowing of the pores, but by a partial collapse of the pore network

  3. Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

    Directory of Open Access Journals (Sweden)

    F. Burgio

    2014-10-01

    Full Text Available Chemical Vapour Infiltration (CVI technique has been long used to produce carbon/carbon composites. The Pyrolytic Carbon (Py-C matrix infiltrated by CVI could have different microstructures, i.e. Rough Laminar (RL, Smooth Laminar (SL or Isotropic (ISO. These matrix microstructures, characterized by different properties, influence the mechanical behaviour of the obtained composites. Tailoring the process parameters, it is possible to direct the infiltration towards a specific Py-C type. However, the factors, influencing the production of a specific matrix microstructure, are numerous and interconnected, e.g. temperature, pressure, flow rates etc. Due to the complexity of the physical and chemical phenomena involved in CVI process, up to now it has not been possible to obtain a general correlation between CVI process parameters and Py–C microstructure. This study is aimed at investigating the relationship between infiltration temperature and the microstructure of obtained Py-C, for a pilot - sized CVI/CVD reactor. Fixing the other process parameters and varying only the temperature, from 1100°C to 1300°C, the Py-C infiltration was performed on fibrous preforms. Polarized light microscopy, with quantitative measurements of average extinction angle (Ae, and Raman spectroscopy were used to characterize the obtained Py-C microstructures

  4. Cf/C composites: correlation between CVI process parameters and Pyrolytic Carbon microstructure

    Directory of Open Access Journals (Sweden)

    F. Burgio

    2014-10-01

    Full Text Available Chemical Vapour Infiltration (CVI technique has been long used to produce carbon/carbon composites. The Pyrolytic Carbon (Py-C matrix infiltrated by CVI could have different microstructures, i.e. Rough Laminar (RL, Smooth Laminar (SL or Isotropic (ISO. These matrix microstructures, characterized by different properties, influence the mechanical behaviour of the obtained composites. Tailoring the process parameters, it is possible to direct the infiltration towards a specific Py-C type. However, the factors, influencing the production of a specific matrix microstructure, are numerous and interconnected, e.g. temperature, pressure, flow rates etc. Due to the complexity of the physical and chemical phenomena involved in CVI process, up to now it has not been possible to obtain a general correlation between CVI process parameters and Py–C microstructure. This study is aimed at investigating the relationship between infiltration temperature and the microstructure of obtained Py-C, for a pilot - sized CVI/CVD reactor. Fixing the other process parameters and varying only the temperature, from 1100°C to 1300°C, the Py-C infiltration was performed on fibrous preforms. Polarized light microscopy, with quantitative measurements of average extinction angle (Ae, and Raman spectroscopy were used to characterize the obtained Py-C microstructures.

  5. Damage to the microbial cell membrane during pyrolytic sugar utilization and strategies for increasing resistance.

    Science.gov (United States)

    Jin, Tao; Rover, Marjorie R; Petersen, Elspeth M; Chi, Zhanyou; Smith, Ryan G; Brown, Robert C; Wen, Zhiyou; Jarboe, Laura R

    2017-09-01

    Lignocellulosic biomass is an appealing feedstock for the production of biorenewable fuels and chemicals, and thermochemical processing is a promising method for depolymerizing it into sugars. However, trace compounds in this pyrolytic sugar syrup are inhibitory to microbial biocatalysts. This study demonstrates that hydrophobic inhibitors damage the cell membrane of ethanologenic Escherichia coli KO11+lgk. Adaptive evolution was employed to identify design strategies for improving pyrolytic sugar tolerance and utilization. Characterization of the resulting evolved strain indicates that increased resistance to the membrane-damaging effects of the pyrolytic sugars can be attributed to a glutamine to leucine mutation at position 29 of carbon storage regulator CsrA. This single amino acid change is sufficient for decreasing EPS protein production and increasing membrane integrity when exposed to pyrolytic sugars.

  6. Contributions for the chemistry, physics and technology of the elementary carbon in various states for the Carbon '76

    International Nuclear Information System (INIS)

    Delle, W.W.

    1976-07-01

    This report is the compilation of a number of papers prepared by KFA Juelich for the 2nd International Carbon Conference CARBON '76 at Baden-Baden, June 28th - July 2nd, 1976. The presentations deal with objectives of chemistry, physics and technology of the elementary carbon in various states including irradiation induced effects on graphite and pyrolytic carbon. The work was partly sponsored by the Bundesministerium fuer Forschung und Technologie of the Federal Republic of Germany as well as by the Government of North-Rhine-Westfalia. (orig.) [de

  7. Effects of deposited pyrolytic carbon on some mechanical properties of zircaloy-4 tubes. Vol. 3

    Energy Technology Data Exchange (ETDEWEB)

    Shrkawy, S W; Abdel-razek, I D; El-Sayed, H A [Metallurgy Department, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    Zircaloy cladding tubes are not compatible with the uranium fuel pellets as they suffer from failure due to pelletclad interaction (PCI). A carbon coating, as used in the canadian CANLUB fuel elements, is thought to improve the cladding performance with respect to the PCI problem. In this paper pyrolytic carbon coating was deposited on zircaloy-4 cladding tubes by the thermal cracking of commercial butant gas at the temperature range 250-450 degree C. In order to evaluate the effect of gaseous species on the mechanical properties of the tubes tensile and microhardness testing measurements were performed on samples prepared from the coated tubes. The fractured surface of the tensile zircaloy tubes and the deposited carbon coating, both, were examined by the SEM. The results of the tensile tests of zircaloy-4 tubes indicated that the coating process has insignificant effect on the ultimate strength of the tubes tested. The values of Vickers hardness numbers were not significantly changed across the tubes thickness. The microstructure of deposited carbon, due to the cracking process, was granular in all the temperature range (250-450 degree C) studied. 9 figs., 1 tab.

  8. Effect of oxygen and hydrogen on microstructure of pyrolytic carbon deposited from thermal decomposition of methane and ethanol

    Science.gov (United States)

    Ren, Biyun; Zhang, Shouyang; He, LiQun; Gu, Shengyue

    2018-05-01

    Chemical vapor infiltration (CVI) is the most extensive industrial preparation of carbon/carbon (C/C) composites. Precursor affects the CVI process considerably. In the present study, using carbon fiber bundles as preforms, methane and ethanol as precursors, the C/C composites were densified by decomposition of various gases in CVI. The thickness and texture of deposited pyrolytic carbon (PyC) were characterized by polarized light microscopy (PLM). The microstructure of PyC was analyzed by Raman spectroscopy. The morphologies of PyC were characterized by scanning electron microscopy (SEM). The composition of PyC was detected by X-ray photoelectron spectroscopy (XPS). Adding hydrogen in methane precursor resulted in a sharp decrease in the deposition rate and texture of PyC. Mixture of methane and ethanol as the precursor improved the deposition rate and texture remarkably. Besides, O element in ethanol was not remained as a constitution of PyC, and it was removed before the formation of PyC.

  9. Mechanical Properties and Structures of Pyrolytic Carbon Coating Layer in HTR Coated Particle Fuel

    International Nuclear Information System (INIS)

    Lee, Young Woo; Kim, Young Min; Kim, Woong Ki; Cho, Moon Sung

    2009-01-01

    The TRISO(tri-isotropic)-coated fuel particle for a HTR(High Temperature gas-cooled Reactor) has a diameter of about 1 mm, composed of a nuclear fuel kernel and four different outer coating layers, consisting of a buffer PyC (pyrolytic carbon) layer, inner PyC layer, SiC layer, and outer PyC layer with different coating thicknesses following a specific fuel design. While the fuel kernel is a source for a heat generation by a nuclear fission of fissile uranium, each of the four coating layers acts as a different role in view of retaining the generated fission products and the other interactions during an in-reactor service. Among these coating layers, PyC properties are scarcely in agreement among various investigators and the dependency of their changes upon the deposition condition is comparatively large due to their additional anisotropic properties. Although a recent review work has contributed to an establishment of relationship between the material properties and QC measurements, the data on the mechanical properties and structural parameters of PyC coating layers remain still unclearly evaluated. A review work on dimensional changes of PyC by neutron irradiation was one of re-evaluative works recently attempted by the authors. In this work, an attempt was made to analyze and re-evaluate the existing data of the experimental results of the mechanical properties, i.e., Young's modulus and fracture stress, in relation with the coating conditions, density and the BAF (Bacon Anisotropy Factor), an important structural parameter, of PyC coating layers obtained from various experiments performed in the early periods of the HTR coated particle development

  10. Pyrolytic graphite gauge for measuring heat flux

    Science.gov (United States)

    Bunker, Robert C. (Inventor); Ewing, Mark E. (Inventor); Shipley, John L. (Inventor)

    2002-01-01

    A gauge for measuring heat flux, especially heat flux encountered in a high temperature environment, is provided. The gauge includes at least one thermocouple and an anisotropic pyrolytic graphite body that covers at least part of, and optionally encases the thermocouple. Heat flux is incident on the anisotropic pyrolytic graphite body by arranging the gauge so that the gauge surface on which convective and radiative fluxes are incident is perpendicular to the basal planes of the pyrolytic graphite. The conductivity of the pyrolytic graphite permits energy, transferred into the pyrolytic graphite body in the form of heat flux on the incident (or facing) surface, to be quickly distributed through the entire pyrolytic graphite body, resulting in small substantially instantaneous temperature gradients. Temperature changes to the body can thereby be measured by the thermocouple, and reduced to quantify the heat flux incident to the body.

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

    Science.gov (United States)

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

    2016-04-05

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

  12. Effects of deposition conditions on the properties of pyrolytic carbon deposited in a fluidized bed

    International Nuclear Information System (INIS)

    Lowden, Richard Andrew; Hunn, John D.; Nunn, Stephen D.; Kercher, Andrew K.; Price, Jeffery R.; Jellison, Gerald Earle Jr.

    2005-01-01

    The high-density, isotropic pyrolytic carbon layer beneath the silicon carbide (IPyC) plays a key role in the irradiation performance of coated particle fuel. The IPyC layer protects the kernel from reactions with chlorine during deposition of the SiC layer, provides structural support for the SiC layer, and protects the SiC from fission products and carbon monoxide. The process conditions used by the Germans to deposit the IPyC coating produced a highly isotropic, but somewhat permeable IPyC coating. The permeability of the IPyC coating was acceptable for use with the dense German UO 2 kernels, but may not be suitable when coating UCO kernels. The UCO kernels are typically more porous and thus have a larger surface area than UO 2 kernels. The lower density and the higher surface area of UCO kernels could make them more susceptible to attack by HCl gas during the silicon carbide (SiC) coating process, which could result in heavy metal dispersion into the buffer and IPyC coatings and a higher level of as-manufactured SiC defects. The relationship between IPyC deposition conditions, permeability, and anisotropy must be understood and the appropriate combination of anisotropy and permeability for particle fuel containing UCO kernels selected. A reference set of processing conditions have been determined from review of historical information and results of earlier coating experiments employing 350 and 500 (micro)m UO 2 kernels. It was decided that a limited study would be conducted, in which only coating gas fraction (CGF) and temperature would be varied. Coatings would be deposited at different rates and with a range of microstructures. Thickness, density, porosity and anisotropy would be measured and permeability evaluated using a chlorine leach test. The results would be used to select the best IPyC coating conditions for use with the available natural enrichment uranium carbide/uranium oxide (NUCO) kernels. The response plots from the investigation of the

  13. The effects of neutron irradiation on the structure of carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eatherly, W.P.; Hollenberg, G. W.; Slagle, O.D.; Watson, R.D.

    1991-01-01

    In this paper irradiation behavior of carbon fibers and carbon-carbon composites are discussed in terms on simple microstructural models. Previous data are discussed in terms of these models. New data are presented for the irradiation-induced dimensional changes of selected carbon-carbon composites. The influence of fiber precursor on carbon- carbon irradiation performance is discussed

  14. Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite

    Energy Technology Data Exchange (ETDEWEB)

    Boutin, F R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    Apparent contradictions in the properties of pyrolytic carbons obtained at 1600 deg C (hardness and graphitization) are studied. It is shown that structure of the deposit is turbostratic with high internal stresses ({delta}{sup -2}), and it graphitizes (by thermal treatment over 2000 deg C) in a similar manner to graphitisable carbon. Because the deposit forms lamellar compounds, it is presumed that the structure is similar to that of graphitisable carbon. Since it is not structure dependant, the hardness originates from the 'growth texture' and is not comparable with the hardness of a non-graphitisable carbon. The pyrolytic carbon studied is composed of regions, on the overage a few microns across, formed by the stacking of small carbon platelets, interlocked and showing a preferred orientation. The mis-orientation of the various regions produces general disorientation. We estimate that the introduction of the particles of some material such as thermal black which are observed in the electron microscope are responsible for the mis-orientation. The density and hardness of the deposit are a result of the interlocking of platelets, which creates a closed porosity and prevents any sliding of the atomic planes. (author) [French] On etudie les proprietes apparemment contradictoires du pyrocarbone 1600 deg C, durete et graphitabilite. On montre que le pyrocarbone possede la structure d'un carbone turbostratique a fort taux de distorsion et qu'il subit, par traitement a des temperatures superieures a 2000 deg C, une transformation de graphitation comparable a celle que l'on observe sur les cokes graphitables. Comme le pyrocarbone forme de plus des composes d'insertion, sa structure est comparable a celle d'un carbone graphitable. La durete, qui n'a pas d'origine structurale, est donc liee a la 'texture de croissance' du depot et ne peut etre comparee a celle d'un coke dur et non graphitable. Le pyrocarbone etudie est constitue de domaines, dont les dimensions sont de l

  15. Re-crystallization of ITO films after carbon irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Usman, Muhammad, E-mail: usmanm@ncp.edu.pk [Experimental Physics Laboratories, National Centre for Physics, Shahdara Valley Road, Quaid-i-Azam University, Islamabad (Pakistan); Khan, Shahid, E-mail: shahidkhan@zju.edu.cn [State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Khan, Majid [Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Abbas, Turab Ali [Experimental Physics Laboratories, National Centre for Physics, Shahdara Valley Road, Quaid-i-Azam University, Islamabad (Pakistan)

    2017-01-15

    Highlights: • Carbon irradiation on ITO destroys crystal structure until threshold ion fluence. • Carbon irradiation induced amorphization in ITO is recoverable at higher fluence. • Optical transmittance is reduced after carbon irradiation. • Electrical resistivity is increased after irradiation with carbon ions in ITO. • Bandgap is reduced with increasing fluence of carbon irradiation. - Abstract: 2.0 MeV carbon ion irradiation effects on Indium Tin Oxide (ITO) thin films on glass substrate are investigated. The films are irradiated with carbon ions in the fluence range of 1 × 10{sup 13} to 1 × 10{sup 15} ions/cm{sup 2}. The irradiation induced effects in ITO are compared before and after ion bombardment by systematic study of structural, optical and electrical properties of the films. The XRD results show polycrystalline nature of un-irradiated ITO films which turns to amorphous state after 1 × 10{sup 13} ions/cm{sup 2} fluence of carbon ions. Further increase in ion fluence to 1 × 10{sup 14} ions/cm{sup 2} re-crystallizes the structure and retains for even higher fluences. A gradual decrease in the electrical conductivity and transmittance of irradiated samples is observed with increasing ion fluence. The band gap of the films is observed to be decreased after carbon irradiation.

  16. Re-crystallization of ITO films after carbon irradiation

    International Nuclear Information System (INIS)

    Usman, Muhammad; Khan, Shahid; Khan, Majid; Abbas, Turab Ali

    2017-01-01

    Highlights: • Carbon irradiation on ITO destroys crystal structure until threshold ion fluence. • Carbon irradiation induced amorphization in ITO is recoverable at higher fluence. • Optical transmittance is reduced after carbon irradiation. • Electrical resistivity is increased after irradiation with carbon ions in ITO. • Bandgap is reduced with increasing fluence of carbon irradiation. - Abstract: 2.0 MeV carbon ion irradiation effects on Indium Tin Oxide (ITO) thin films on glass substrate are investigated. The films are irradiated with carbon ions in the fluence range of 1 × 10"1"3 to 1 × 10"1"5 ions/cm"2. The irradiation induced effects in ITO are compared before and after ion bombardment by systematic study of structural, optical and electrical properties of the films. The XRD results show polycrystalline nature of un-irradiated ITO films which turns to amorphous state after 1 × 10"1"3 ions/cm"2 fluence of carbon ions. Further increase in ion fluence to 1 × 10"1"4 ions/cm"2 re-crystallizes the structure and retains for even higher fluences. A gradual decrease in the electrical conductivity and transmittance of irradiated samples is observed with increasing ion fluence. The band gap of the films is observed to be decreased after carbon irradiation.

  17. Experimental study of pyrolytic boron nitride at high temperature with and without proton and VUV irradiations

    International Nuclear Information System (INIS)

    Balat-Pichelin, M.; Eck, J.; Heurtault, S.; Glénat, H.

    2014-01-01

    Highlights: • New results for the high temperature study of pBN in high vacuum for the heat shield of solar probes. • Physico-chemical behavior of pBN studied up to 1700 K with proton and VUV irradiations. • Rather low effect of synergistic aggressions on the microstructure of pBN material. • The α/ε ratio of pBN coating on C/C measured up to 2200 K is 20% lower than for the C/C itself. - Abstract: In the frame of future exploration missions such as Solar Probe Plus (NASA) and PHOIBOS (ESA), research was carried out to study pyrolytic BN material envisaged as coating for their heat shields. The physico-chemical behavior of CVD pBN at very high temperature with or without hydrogen ions and VUV (Vacuum Ultra-Violet) irradiations was studied in high vacuum together with the in situ measurement of the thermal radiative properties conditioning the thermal equilibrium of the heat shield. Experimental results obtained on massive pBN samples are presented through in situ mass spectrometry and mass loss rate, and post-test microstructural characterization by XRD, SEM, AFM and nano-indentation techniques, some of them leading to mechanical properties. It could be concluded that synergistic effect of high temperature, protons and VUV radiation has an impact on the emission of gaseous species, the mass loss rate and the mechanical properties of the material

  18. Co-pyrolysis behaviour and kinetic of two typical solid wastes in China and characterisation of activated carbon prepared from pyrolytic char.

    Science.gov (United States)

    Ma, Yuhui; Niu, Ruxuan; Wang, Xiaona; Wang, Qunhui; Wang, Xiaoqiang; Sun, Xiaohong

    2014-11-01

    This is the first study on the co-pyrolysis of spent substrate of Pleurotus ostreatus and coal tar pitch, and the activated carbon prepared from the pyrolytic char. Thermogravimetry (TG) analysis was carried out taking spent substrate, coal tar pitch and spent substrate-coal tar pitch mixture. The activation energies of pyrolysis reactions were obtained via the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. The kinetic models were determined by the master-plots method. The activated carbons were characterised by N2-adsorption, Fourier transform infrared spectroscopy and X-ray diffraction. Experimental results demonstrated a synergistic effect happened during co-pyrolysis, which was characterised by a decreased maximum decomposition rate and an enhanced char yield. The average activation energies of the pyrolysis reactions of spent substrate, coal tar pitch and the mixture were 115.94, 72.92 and 94.38 kJ mol(-1) for the Flynn-Wall-Ozawa method, and 112.17, 65.62 and 89.91 kJ mol(-1) for the Kissinger-Akahira-Sunose method. The reaction model functions were f(α) = (1-α)(3.42), (1-α)(1.72) and (1-α)(3.07) for spent substrate, coal tar pitch and the mixture, respectively. The mixture char-derived activated carbon had a Brunauer-Emmett-Teller surface area up to 1337 m(2) g(-1) and a total pore volume of 0.680 cm(3) g(-1). Mixing spent substrate with coal tar pitch led to the creation of more micropores and a higher surface area compared with the single spent substrate and coal tar pitch char. Also, the mixture char-derived activated carbon had a higher proportion of aromatic stacking. This study provides a reference for the utilisation of spent substrate and coal tar pitch via co-pyrolysis, and their pyrolytic char as a promising precursor of activated carbon. © The Author(s) 2014.

  19. Role of oxygen-containing functional groups in forest fire-generated and pyrolytic chars for immobilization of copper and nickel.

    Science.gov (United States)

    Esfandbod, Maryam; Merritt, Christopher R; Rashti, Mehran Rezaei; Singh, Balwant; Boyd, Sue E; Srivastava, Prashant; Brown, Christopher L; Butler, Orpheus M; Kookana, Rai S; Chen, Chengrong

    2017-01-01

    Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescribed burn offs for fire management. The objective of this study was to elucidate mechanistic interactions of copper (Cu 2+ ) and nickel (Ni 2+ ) with different chars produced by pyrolysis (green waste, GW; blue-Mallee, BM) and forest fires (fresh-burnt by prescribed fire, FC; aged char produced by wild fire, AC). The pyrolytic chars were more effective sorbents of Cu 2+ (∼11 times) and Ni 2+ (∼5 times) compared with the forest fire chars. Both cross-polarization (CPMAS-NMR) and Bloch decay (BDMAS-NMR) 13 C NMR spectroscopies showed that forest fire chars have higher woody components (aromatic functional groups) and lower polar groups (e.g. O-alkyl C) compared with the pyrolytic chars. The polarity index was greater in the pyrolytic chars (0.99-1.34) than in the fire-generated chars (0.98-1.15), while aromaticity was lower in the former than in the latter. Fourier transform infrared (FTIR) and Raman spectroscopies indicated the binding of carbonate and phosphate with both Cu 2+ and Ni 2+ in all chars, but with a greater extent in pyrolytic than forest fire-generated chars. These findings have demonstrated the key role of char's oxygen-containing functional groups in determining their sorption capacity for the Cu 2+ and Ni 2+ in contaminated lands. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Irradiation of carbon nanotubes with carbon projectiles: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Denton, Cristian D. [Departamento de Fisica Aplicada, Universidad de Alicante, 03080 Alicante (Spain); Heredia-Avalos, Santiago; Moreno-Marin, Juan Carlos [Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Senal, Universidad de Alicante, 03080 Alicante (Spain)

    2013-04-15

    The irradiation of carbon based nanostructures with ions and electrons has been shown to be an appropriate tool to tailor their properties. The defects induced in the nanostructures during irradiation are able to modify their mechanical and electronic properties. Here we simulate the irradiation of carbon nanotubes with carbon ions using a molecular dynamics code. We use the Tersoff potential joined smoothly to the Universal Ziegler-Biersack-Littmark potential at short distances. We study the number of defects produced after irradiation with a single carbon ion finding a saturation with its energy at {proportional_to} 3 keV. We observe, after continuum irradiation with low energy ions, the formation of bumps in the irradiated region. For larger energy ions we find that the diameter of the nanotube shrinks as shown in previous works. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Cyclic fatigue-crack propagation, stress-corrosion, and fracture-toughness behavior in pyrolytic carbon-coated graphite for prosthetic heart valve applications.

    Science.gov (United States)

    Ritchie, R O; Dauskardt, R H; Yu, W K; Brendzel, A M

    1990-02-01

    Fracture-mechanics tests were performed to characterize the cyclic fatigue, stress-corrosion cracking, and fracture-toughness behavior of a pyrolytic carbon-coated graphite composite material used in the manufacture of cardiac valve prostheses. Testing was carried out using compact tension C(T) samples containing "atomically" sharp precracks, both in room-temperature air and principally in a simulated physiological environment of 37 degrees C Ringer's lactate solution. Under sustained (monotonic) loads, the composite exhibited resistance-curve behavior, with a fracture toughness (KIc) between 1.1 and 1.9 MPa square root of m, and subcritical stress-corrosion crack velocities (da/dt) which were a function of the stress intensity K raised to the 74th power (over the range approximately 10(-9) to over 10(-5) m/s). More importantly, contrary to common perception, under cyclic loading conditions the composite was found to display true (cyclic) fatigue failure in both environments; fatigue-crack growth rates (da/dN) were seen to be a function of the 19th power of the stress-intensity range delta K (over the range approximately 10(-11) to over 10(-8) m/cycle). As subcritical crack velocities under cyclic loading were found to be many orders of magnitude faster than those measured under equivalent monotonic loads and to occur at typically 45% lower stress-intensity levels, cyclic fatigue in pyrolytic carbon-coated graphite is reasoned to be a vital consideration in the design and life-prediction procedures of prosthetic devices manufactured from this material.

  2. Study of composite MWCNT/pyrolytic Cr interface by NEXAFS spectroscopy

    International Nuclear Information System (INIS)

    Petrova, O V; Nekipelov, S V; Mingaleva, A E; Sivkov, V N; Obiedkov, A M; Kaverin, B S; Kremlev, K V; Ketkov, S Yu; Gusev, S A; Vyalikh, D V; Molodtsov, S L

    2016-01-01

    A composite material based on MWCNT covered by pyrolytic Cr has been prepared by MOCVD growth technique using bis(arene)chromium compounds as the pyrolytic Cr source. Their structures and morphologies were preliminary studied by X-ray diffraction and scanning and scanning electron microscopy. The atomic and chemical composition of the interface, MWCNT surface and Cr-coating of the composite were studied by total electron yield mode in the range NEXAFS C1s - and Cr2p - absorption edge with use of synchrotron radiation of RGBL at BESSY-II. The study has shown that top layers of the MWCNT in composite have no essential destruction, the coating of the MWCNT surfaces is continuous and consists of Cr 2 O 3 . The chromium oxide adhesion is provided by chemical binding between the carbon atoms of the MWCNT top layer and the oxygen atoms of the coating. (paper)

  3. Investigations on neutron irradiated 3D carbon fibre reinforced carbon composite material

    Science.gov (United States)

    Venugopalan, Ramani; Alur, V. D.; Patra, A. K.; Acharya, R.; Srivastava, D.

    2018-04-01

    As against conventional graphite materials carbon-carbon (C/C) composite materials are now being contemplated as the promising candidate materials for the high temperature and fusion reactor owing to their high thermal conductivity and high thermal resistance, better mechanical/thermal properties and irradiation stability. The current need is for focused research on novel carbon materials for future new generation nuclear reactors. The advantage of carbon-carbon composite is that the microstructure and the properties can be tailor made. The present study encompasses the irradiation of 3D carbon composite prepared by reinforcement using PAN carbon fibers for nuclear application. The carbon fiber reinforced composite was subjected to neutron irradiation in the research reactor DHRUVA. The irradiated samples were characterized by Differential Scanning Calorimetry (DSC), small angle neutron scattering (SANS), XRD and Raman spectroscopy. The DSC scans were taken in argon atmosphere under a linear heating program. The scanning was carried out at temperature range from 30 °C to 700 °C at different heating rates in argon atmosphere along with reference as unirradiated carbon composite. The Wigner energy spectrum of irradiated composite showed two peaks corresponding to 200 °C and 600 °C. The stored energy data for the samples were in the range 110-170 J/g for temperature ranging from 30 °C to 700 °C. The Wigner energy spectrum of irradiated carbon composite did not indicate spontaneous temperature rise during thermal annealing. Small angle neutron scattering (SANS) experiments have been carried out to investigate neutron irradiation induced changes in porosity of the composite samples. SANS data were recorded in the scattering wave vector range of 0.17 nm-1 to 3.5 nm-1. Comparison of SANS profiles of irradiated and unirradiated samples indicates significant change in pore morphology. Pore size distributions of the samples follow power law size distribution with

  4. Pyrolysis of de-oiled seed cake of Jatropha Curcas and catalytic steam reforming of pyrolytic bio-oil to hydrogen.

    Science.gov (United States)

    Renny, Andrew; Santhosh, Viswanathan; Somkuwar, Nitin; Gokak, D T; Sharma, Pankaj; Bhargava, Sanjay

    2016-11-01

    The aim of this work was to study the pyrolysis of de-oiled seed cake of Jatropha Curcas and catalytic steam reforming of pyrolytic bio-oil to hydrogen. As per literature, presence of heavy nitrogenous and oxygenated compounds leads to catalyst deactivation. Here, an attempt has been made to tune pyrolytic reactions to optimize the N and O content of the pyrolytic bio-oil. Bio-oil conversion and hydrogen yield decreased as reaction progressed, which attributes to temporary loss of catalytic activity by blockage of catalyst pores by carbon deposition. Further, retention of steam reforming activity after repetitive steam activation suggests long-term catalyst usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Thermal Pyrolytic Graphite Enhanced Components

    Science.gov (United States)

    Hardesty, Robert E. (Inventor)

    2015-01-01

    A thermally conductive composite material, a thermal transfer device made of the material, and a method for making the material are disclosed. Apertures or depressions are formed in aluminum or aluminum alloy. Plugs are formed of thermal pyrolytic graphite. An amount of silicon sufficient for liquid interface diffusion bonding is applied, for example by vapor deposition or use of aluminum silicon alloy foil. The plugs are inserted in the apertures or depressions. Bonding energy is applied, for example by applying pressure and heat using a hot isostatic press. The thermal pyrolytic graphite, aluminum or aluminum alloy and silicon form a eutectic alloy. As a result, the plugs are bonded into the apertures or depressions. The composite material can be machined to produce finished devices such as the thermal transfer device. Thermally conductive planes of the thermal pyrolytic graphite plugs may be aligned in parallel to present a thermal conduction path.

  6. Effect of neutron irradiation on vitreous carbon

    International Nuclear Information System (INIS)

    Kurolenkin, E.I.; Virgil'ev, Yu.S.; Chugunova, T.K.

    1989-01-01

    The change in mass (m), volume (V), specific electric resistance (ρ), coefficient of linear thermal expansion (α), dynamic elasticity modulus (E), and limit of bending strength (σ) of vitreous carbon are studied upon neutron irradiation. Samples for study were two forms of vitreous carbon obtained by hardening thermally reactive polymers at 900-1,000 degree K. Phenol-formaldehyde (bakelite lacquer A, Bakelite A) and furfural-phenol-formaldehyde (FM-2) resin were used. They were irradiated in the experimental water - water VVR-M reactor between 360-1,030 degree K. The maximal neutron flux was 1.65·10 21 neut/cm 2 . Neutron irradiation of vitreous carbon led to its shrinkage and accompanied weakening. Shrinkage and weakening of vitreous carbon was decreased with an increase of treatment and irradiation temperatures

  7. Pyrolytic conversion of plastic and rubber waste to hydrocarbons with basic salt catalysts

    Science.gov (United States)

    Wingfield, Jr., Robert C.; Braslaw, Jacob; Gealer, Roy L.

    1985-01-01

    The invention relates to a process for improving the pyrolytic conversion of waste selected from rubber and plastic to low molecular weight olefinic materials by employing basis salt catalysts in the waste mixture. The salts comprise alkali or alkaline earth compounds, particularly sodium carbonate, in an amount of greater than about 1 weight percent based on the waste feed.

  8. Irradiation-induced structure and property changes in tokamak plasma-facing, carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.

    1994-01-01

    Carbon-carbon composites are an attractive choice for fusion reactor plasma-facing components because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation plasma fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER), will require advanced carbon-carbon composite materials possessing high thermal conductivity to manage the anticipated severe heat loads. Moreover, ignition machines such as ITER will produce large neutron fluxes. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from two irradiation experiments are reported and discussed here. Carbon-carbon composite materials were irradiated in target capsules in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). A peak damage dose of 4.7 displacements per atom (dpa) at 600 degree C was attained. The carbon materials irradiated included uni-directional, two-directional, and three-directional carbon-carbon composites. Dimensional changes are reported for the composite materials and are related to single crystal dimensional changes through fiber and composite structural models. Moreover, the irradiation-induced dimensional changes are reported and discussed in terms of their architecture, fiber type, and graphitization temperature. The effect of neutron irradiation on thermal conductivity of two three-directional, carbon-carbon composites is reported and the recovery of thermal conductivity due to thermal annealing is discussed

  9. Structures and electrochemical properties of pyrolytic carbon films infiltrated from gas phase into electro-conductive substrates derived from wood

    International Nuclear Information System (INIS)

    Ohzawa, Yoshimi; Mitani, Masami; Li, Jianling; Nakajima, Tsuyoshi

    2004-01-01

    Using the pressure-pulsed chemical vapor infiltration technique, pyrolytic carbon (pyrocarbon) films were deposited into two sorts of conductive porous substrates, that is, the carbonized wood (A) and the TiN-coated wood (B). Structures and electrochemical properties were investigated as the negative electrodes of lithium-ion secondary battery. The electrodes had the three-dimensionally continuous current paths in the pyrocarbon-based anodes without the organic binders and the additional conductive fillers. The pyrocarbon films adhered tightly to the carbonized wood or TiN as current collector. These macro-structures of electrodes were effective in improving the high rate property. The sort of substrates affected the nano-structure of pyrocarbon. The pyrocarbon in sample (A) had the relatively high crystallinity, whereas the pyrocarbon in sample (B) was disordered. The capacity of pyrocarbon in sample (B) was higher than that of sample (A), reflecting the disordered microstructure of pyrocarbon film (B). However, sample (A) showed higher Coulombic efficiency at first cycle (i.e. 87%) than that of sample (B), which would result from the high crystallinity, laminar microstructure and low surface area of pyrocarbon in sample (A)

  10. Nitrite electrochemical sensor based on prussian blue/single-walled carbon nanotubes modified pyrolytic graphite electrode

    CSIR Research Space (South Africa)

    Adekunle, AS

    2011-09-01

    Full Text Available Nitrite, NO2- (in neutral), and NO (in acidic media) were used as analytical probe to investigate the electrocatalytic properties of Prussian blue nanoparticles (PB) modified edge plane pyrolytic graphite (EPPG) electrode. Results indicate...

  11. Modification of graphite structure by irradiation, revealed by thermal oxidation. Examination by electronic microscopy

    International Nuclear Information System (INIS)

    Rouaud, Michel

    1969-01-01

    Based on the analysis of images obtained by electronic microscopy, this document reports the comparative study of the action of neutrons on three different graphites: a natural one (Ticonderoga) and two pyrolytic ones (Carbone-Lorraine and Raytheon). The approach is based on the modification of features of thermal oxidation of graphites by dry air after irradiation. Different corrosion features are identified. The author states that there seems to be a relationship between the number and shape of these features, and defects existing on the irradiated graphite before oxidation. For low doses, the feature aspect varies with depth at which oxidation occurs. For higher doses, the aspect remains the same [fr

  12. Pyrolytic citrate synthesis and ozone annealing

    International Nuclear Information System (INIS)

    Celani, F.; Saggese, A.; Giovannella, C.; Messi, R.; Merlo, V.

    1988-01-01

    A pyrolytic procedure is described that via a citrate synthesis allowed us to obtain very fine grained YBCO powders that, after a first furnace thermal treatment in ozone, results already to contain a large amount of superconducting microcrystals. A second identical thermal treatment gives a final product strongly textured, as shown by magnetic torque measurements. Complementary structural and diamagnetic measurement show the high quality of these sintered pellets. The role covered by both the pyrolytic preparation and the ozone annealing are discussed

  13. Boron ion irradiation induced structural and surface modification of glassy carbon

    International Nuclear Information System (INIS)

    Kalijadis, Ana; Jovanović, Zoran; Cvijović-Alagić, Ivana; Laušević, Zoran

    2013-01-01

    The incorporation of boron into glassy carbon was achieved by irradiating two different types of targets: glassy carbon polymer precursor and carbonized glassy carbon. Targets were irradiated with a 45 keV B 3+ ion beam in the fluence range of 5 × 10 15 –5 × 10 16 ions cm −2 . For both types of targets, the implanted boron was located in a narrow region under the surface. Following irradiation, the polymer was carbonized under the same condition as the glassy carbon samples (at 1273 K) and examined by Raman spectroscopy, temperature programmed desorption, hardness and cyclic voltammetry measurements. Structural analysis showed that during the carbonization process of the irradiated polymers, boron is substitutionally incorporated into the glassy carbon structure, while for irradiated carbonized glassy carbon samples, boron irradiation caused an increase of the sp 3 carbon fraction, which is most pronounced for the highest fluence irradiation. Further analyses showed that different nature of boron incorporation, and thus changed structural parameters, are crucial for obtaining glassy carbon samples with modified mechanical, chemical and electrochemical properties over a wide range

  14. Amorphous molecular junctions produced by ion irradiation on carbon nanotubes

    International Nuclear Information System (INIS)

    Wang Zhenxia; Yu Liping; Zhang Wei; Ding Yinfeng; Li Yulan; Han Jiaguang; Zhu Zhiyuan; Xu Hongjie; He Guowei; Chen Yi; Hu Gang

    2004-01-01

    Experiments and molecular dynamics have demonstrated that electron irradiation could create molecular junctions between crossed single-wall carbon nanotubes. Recently molecular dynamics computation predicted that ion irradiation could also join single-walled carbon nanotubes. Employing carbon ion irradiation on multi-walled carbon nanotubes, we find that these nanotubes evolve into amorphous carbon nanowires, more importantly, during the process of which various molecular junctions of amorphous nanowires are formed by welding from crossed carbon nanotubes. It demonstrates that ion-beam irradiation could be an effective way not only for the welding of nanotubes but also for the formation of nanowire junctions

  15. Separation, hydrolysis and fermentation of pyrolytic sugars to produce ethanol and lipids.

    Science.gov (United States)

    Lian, Jieni; Chen, Shulin; Zhou, Shuai; Wang, Zhouhong; O'Fallon, James; Li, Chun-Zhu; Garcia-Perez, Manuel

    2010-12-01

    This paper describes a new scheme to convert anhydrosugars found in pyrolysis oils into ethanol and lipids. Pyrolytic sugars were separated from phenols by solvent extraction and were hydrolyzed into glucose using sulfuric acid as a catalyst. Toxicological studies showed that phenols and acids were the main species inhibiting growth of the yeast Saccharomyces cerevisiae. The sulfuric acids, and carboxylic acids from the bio-oils, were neutralized with Ba(OH)(2). The phase rich in sugar was further detoxified with activated carbon. The resulting aqueous phase rich in glucose was fermented with three different yeasts: S. cerevisiae to produce ethanol, and Cryptococcus curvatus and Rhodotorula glutinis to produce lipids. Yields as high as 0.473 g ethanol/g glucose and 0.167 g lipids/g sugar (0.266 g ethanol equivalent/g sugar), were obtained. These results confirm that pyrolytic sugar fermentation to produce ethanol is more efficient than for lipid production. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  16. Ion irradiation effects on tensile properties of carbon fibres

    International Nuclear Information System (INIS)

    Kurumada, A.; Ishihara, M.; Baba, S.; Aihara, J.

    2004-01-01

    Carbon/carbon composite materials have high thermal conductivity and excellent mechanical properties at high temperatures. They have been used as structural materials at high temperatures in fission and experimental fusion reactors. The changes in the microstructures and the mechanical properties due to irradiation damage must be measured for the safety design and the life assessment of the materials. The purpose of this study is to obtain a basic knowledge of the development of new carbon composite materials having high thermal conductivity and excellent resistance to irradiation damage. Five kinds of carbon fibres were selected, including a vapour growth carbon fibre (VGCF; K1100X), a polyacrylonitrile-based fibre (PAN; M55JB by Toray Corp.), two meso-phase pitch-based fibres (YS-15-60S and YS-70-60S by Nippon Graphite Fiber Corp.) and a pitch-based fibre (K13C2U by Mitsubishi Chemical Co.). They were irradiated by high-energy carbon, nickel and argon ions. Irradiation damages in the carbon fibres are expected to be uniform across the cross-section, as the diameters of the carbon fibres are about 20 μm and are sufficiently smaller than the ranges of ions. The cross-sectional areas increased due to ion irradiation, with the exception of the K1100X of VGCF. One of the reasons for the increases is the swelling of carbon basal planes due to lattice defects in the graphite interlayer. The tensile strengths and the Young's moduli decreased due to ion irradiation except for the K1100X of VGCF and the YS-15-60S of meso-phase pitch-based fibres. One of the reasons for the decreases is thought to be that the microstructures of carbon fibres are damaged in the axial direction, as ions were irradiated vertically with respect to the longitudinal direction of carbon fibres. The results of this study indicate that the VGCF and the meso-phase pitch-based carbon fibres could be useful as reinforcement fibres of new carbon composite materials having high thermal conductivity and

  17. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe135 penetration for molten salt breeder reactor

    International Nuclear Information System (INIS)

    Song, Jinliang; Zhao, Yanling; He, Xiujie; Zhang, Baoliang; Xu, Li; He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping; Bai, Shuo

    2015-01-01

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10 −8 cm 2 /s. • The coated graphite can inhibit the liquid fluoride salt and Xe 135 penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe 135 penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10 5 Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10 5 Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10 5 Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe 135 penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10 −12 m 2 /s, much less than 1.21 × 10 −6 m 2 /s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe 135 penetration

  18. Similarity between the effects of carbon-ion irradiation and X-irradiation on the development of rat brain

    International Nuclear Information System (INIS)

    Inouye, Minoru; Hayasaka, Shizu; Murata, Yoshiharu; Takahashi, Sentaro; Kubota, Yoshihisa

    2000-01-01

    The effects of carbon-ion irradiation and X-irradiation on the development of rat brain were compared. Twenty pregnant rats were injected with bromodeoxyuridine (BrdU) at 9 pm on day 18 pregnancy and divided into five groups. Three hours after injection (day 19.0) one group was exposed to 290 MeV/u carbon-ion radiation by a single dose of 1.5 Gy. Other groups were exposed to X-radiation by 1.5, 2.0 or 2.5 Gy, or sham-treated, respectively. Fetuses were removed from one dam in each group 8 h after exposure and examined histologically. Extensive cell death was observed in the brain mantle from the irradiated groups. The cell death after 1.5 Gy carbon-ion irradiation was remarkably more extensive than that after 1.5 Gy X-irradiation, but comparable to that after 2.0 Gy or 2.5 Gy X-irradiation. The remaining rats were allowed to give birth and the offspring were sacrificed at 6 weeks of age. All of the irradiated offspring manifested microcephaly. The size of the brain mantle exposed to 1.5 Gy carbon-ion radiation was significantly smaller than that exposed to 1.5 Gy X-radiation and larger than that exposed to 2.5 Gy X-radiation. A histological examination of the cerebral cortex revealed that cortical layers II-IV were malformed. The defect by 1.5 Gy carbon-ion irradiation was more severe than that by the same dose of X-irradiation. Although the BrdU-incorporated neurons were greatly reduced in number in all irradiated groups, these cells reached the superficial area of the cortex. These findings indicated that the effects of both carbon-ion irradiation and X-irradiation on the development of rat brain are similar in character, and the effect of 1.5 Gy carbon-ion irradiation compares to that of 2.0-2.5 Gy X-irradiation. (author)

  19. Improvement of carbon fibre surface properties using electron beam irradiation

    International Nuclear Information System (INIS)

    Eddy Segura Pino; Luci Diva Brocardo Machado; Claudia Giovedi

    2006-01-01

    Carbon fiber-reinforced advance composites have been used for structural applications, mainly due to their mechanical properties, and additional features such as high strength-to-weight ratio, stiffness-to-weight ratio, corrosion resistance and wear properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between the components that are fiber and polymeric matrix. The greatest challenge is to improve adhesion between components having elasticity modulus which differ by orders of magnitude and furthermore they are immiscible in each other. Another important factor is the sizing material on the carbon fiber, which protects the carbon fiber filaments and must be compatible with the matrix material in order to improve the adhesion process. The interaction of ionizing radiation from electron beam can induce in the irradiated material the formation of very active centers and free radicals. Further evolution of these active species can significantly modify structure and properties not only in the irradiated polymeric matrix but also on the fiber surface. So that, fiber and matrix play an important role in the production of chemical bonds, which promote better adhesion between both materials improving the composite mechanical performance. The aim of this work was to improve the surface properties of the carbon fiber surface using ionizing radiation from an electron beam in order to obtain improvement of the adhesion properties in the resulted composite. Commercial carbon fiber roving of high tensile strength with 12 000 filaments named 12 k, and sizing material of epoxy resin modified by ester groups was studied. EB irradiation has been carried out at the Institute for Nuclear and Energy Research (IPEN) facilities using a 1.5 MeV 37.5 kW Dynamitron electron accelerator model JOB-188. Rovings of carbon fibers with 1.78 g cm -3 density and 0.13 mm thickness were irradiated with 0.555 MeV, 6.43 mA and

  20. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration for molten salt breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jinliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Yanling, E-mail: jlsong1982@yeah.net [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); He, Xiujie; Zhang, Baoliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, Li [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Bai, Shuo [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-01-15

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10{sup −8} cm{sup 2}/s. • The coated graphite can inhibit the liquid fluoride salt and Xe{sup 135} penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10{sup 5} Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10{sup 5} Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10{sup 5} Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe{sup 135} penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10{sup −12} m{sup 2}/s, much less than 1.21 × 10{sup −6} m{sup 2}/s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe{sup 135} penetration.

  1. Wafer-scale laser lithography. I. Pyrolytic deposition of metal microstructures

    International Nuclear Information System (INIS)

    Herman, I.P.; Hyde, R.A.; McWilliams, B.M.; Weisberg, A.H.; Wood, L.L.

    1982-01-01

    Mechanisms for laser-driven pyrolytic deposition of micron-scale metal structures on crystalline silicon have been studied. Models have been developed to predict temporal and spatial propeties of laser-induced pyrolytic deposition processes. An argon ion laser-based apparatus has been used to deposit metal by pyrolytic decomposition of metal alkyl and carbonyl compounds, in order to evaluate the models. These results of these studies are discussed, along with their implications for the high-speed creation of micron-scale metal structures in ultra-large scale integrated circuit systems. 4 figures

  2. The effect of neutron irradiation on the structure and properties of carbon-carbon composite materials

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eatherly, W.P.; Robbins, J.M.; Strizak, J.P.

    1991-01-01

    Carbon-based materials are an attractive choice for fusion reactor plasma facing components (PFCs) because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation plasma fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER), will require advanced carbon-carbon composite materials possessing extremely high thermal conductivity to manage the anticipated severe heat loads. Moreover, ignition machines such as ITER will produce high neutron fluxes. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from an irradiation experiment are reported and discussed here. Fusion relevant graphite and carbon-carbon composites were irradiated in a target capsule in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). A peak damage dose of 1.59 dpa at 600 degrees C was attained. The carbon materials irradiated included nuclear graphite grade H-451 and one-, two-, and three-directional carbon-carbon composite materials. Dimensional changes, thermal conductivity and strength are reported for the materials examined. The influence of fiber type, architecture, and heat treatment temperature on properties and irradiation behavior are reported. Carbon-Carbon composite dimensional changes are interpreted in terms of simple microstructural models

  3. Pyrolytic product characteristics of biosludge from the wastewater treatment plant of a petrochemical industry.

    Science.gov (United States)

    Lin, Kuo-Hsiung; Hsu, Hui-Tsung; Ko, Ya-Wen; Shieh, Zhu-Xin; Chiang, Hung-Lung

    2009-11-15

    Biosludge was produced from the wastewater treatment plant of a petrochemical industry. The element compositions of pyrolytic residues, CO, CO(2), NOx, SOx, total hydrocarbons and detailed volatile organic compounds of pyrolytic gas, and C, H, N, S content and compositions in biofuel were determined in this study. Generally, 75-80% water content in sludge cakes and about 65-70% weight of water vapor and volatile compounds were volatilized during the drying process. Propene, propane, 1-butene, n-butane, isobutene, toluene and benzene were the major volatile organic compounds (VOCs) of the pyrolytic gas, and the concentrations for most of the top 20 VOC species were greater than 5 ppm. C(5)-C(9) compounds contributed 60% by weight of biofuel; 4-hydroxy-4-methyl-2-pentanone was the highest species, accounting for 28-53% of biofuel at various pyrolytic temperatures. Based on the dried residues, there was 8.5-13% weight in pyrolytic residues, 62-82% weight in liquid products (water and crude oil) and 5.8-30% weight in the gas phase after pyrolytic processing at 500-800 degrees C. Finally, 1.5-2.5 wt% liquid fuel was produced after the distillation process. The pyrolytic residues could be reused, the pyrolytic liquid product could be used as a fuel after distillation, and the pyrolytic gas could be recycled in the pyrolytic process to achieve non-toxic discharge and reduce the cost of sludge disposal.

  4. Study by electronic microscopy of corrosion features of graphite after hot oxidation (air, 620 C)

    International Nuclear Information System (INIS)

    Jodon de Villeroche, Suzanne

    1968-01-01

    The author reports the study of corrosion features of graphite after hot oxidation in the air at 620 C. It is based on observations made by electronic microscopy. This study comes after another one dedicated to oxidation features obtained by hot corrosion of natural graphite, and aims at comparing pyrolytic graphite before and after irradiation in an atomic pile, and at performing tests on a graphite processed with ozone. After a recall of generalities about natural graphite and of some issues related to hot corrosion of natural graphite, the author presents some characteristics and features of irradiated and non-irradiated pyrolytic graphite. He reports the study of the oxidation of samples of pyrolytic graphite: production of thin lamellae, production of glaze-carbon replicates, oxidation of irradiated and of non-irradiated graphite, healing of irradiation defects, and oxidation of ozone-processed natural graphite [fr

  5. Structural changes induced by electron irradiation

    International Nuclear Information System (INIS)

    Koike, J.; Pedraza, D.F.

    1993-01-01

    Highly oriented pyrolytic graphite was irradiated at room temperature with 300 kV electrons. Transmission electron microscopy and electron energy loss spectroscopy were employed to study the structural changes produced by irradiation. The occurrence of a continuous ring intensity in the selected area diffraction (SAD) pattern obtained on a specimen irradiated with the electron beam parallel to the c-crystallographic axis indicated that microstructural changes had occurred. However, from the SAD pattern obtained for the specimens tilted relative to the irradiation direction, it was found that up to a fluence of 1.1x10 27 e/m 2 graphite remained crystalline. An SAD pattern of a specimen irradiated with the electron beam perpendicular to the c-axis confirmed the persistence of crystalline order. High resolution electron microscopy showed that ordering along the c-axis direction remained. A density reduction of 8.9% due to irradiation was determined from the plasmon frequency shift. A qualitative model is proposed to explain these observations. A new determination of the threshold displacement energy, Ed, of carbon atoms in graphite was done by examining the appearance of a continuous ring in the SAD pattern at various electron energies. A value of 30 eV was obtained whether the incident electron beam was parallel or perpendicular to the c-axis, demonstrating that Ed is independent of the displacement direction

  6. Continuous thermal degradation of pyrolytic oil in a bench scale CSTR reaction system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyong Hwan; Nam, Ki Yun [Climate Change Technology Research Division, Korea Institute of Energy Research, 102 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea)

    2010-05-15

    Continuous thermal degradation of two pyrolytic oils with low (LPO) and high boiling point distribution (HPO) was conducted in a constant stirrer tank reactor (CSTR) with bench scale. Raw pyrolytic oil as a reactant was obtained from the commercial rotary kiln pyrolysis plant for municipal plastic waste. The degradation experiment was conducted by temperature programming with 10 C/min of heating rate up to 450 C and then maintained with long lapse time at 450 C. Liquid product was sampled at initial reaction time with different degradation temperatures up to 450 C and then constant interval lapse time at 450 C. The product characteristics over two pyrolytic oils were compared by using a continuous reaction system. As a reactant, heavy pyrolytic oil (HPO) showed higher boiling point distribution than that of diesel and also light pyrolytic oil (LPO) was mainly consisting of a mixture of gasoline and kerosene range components. In the continuous reaction, LPO showed higher yield of liquid product and lower residue than those of HPO. The characteristics of liquid products were influenced by the type of raw pyrolytic oil. Also, the result obtained under degradation temperature programming was described. (author)

  7. Luminescence imaging of water during carbon-ion irradiation for range estimation

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Akagi, Takashi; Yamashita, Tomohiro [Hygo Ion Beam Medical Center, Hyogo 679-5165 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Aichi 462-8508 (Japan)

    2016-05-15

    Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

  8. Luminescence imaging of water during carbon-ion irradiation for range estimation

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Akagi, Takashi; Yamashita, Tomohiro; Toshito, Toshiyuki

    2016-01-01

    Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

  9. Evaluation of the mechanical properties of carbon fiber after electron beam irradiation

    International Nuclear Information System (INIS)

    Giovedi, Claudia; Diva Brocardo Machado, Luci; Augusto, Marcos; Segura Pino, Eddy; Radino, Patricia

    2005-01-01

    Carbon fibers are used as reinforcement material in epoxy matrix in advanced composites. An important aspect of the mechanical properties of composites is associated to the adhesion between the surface of the carbon fiber and the epoxy matrix. This paper aimed to the evaluation of the effects of EB irradiation on the tensile properties of two different carbon fibers prepared as resin-impregnated specimens. The fibers were EB irradiated before the preparation of the resin-impregnated specimens for mechanical tests. Observations of the specimens after breakage have shown that EB irradiation promoted significant changes in the failure mode. Furthermore, the tensile strength data obtained for resin-impregnated specimens prepared with carbons fibers previously irradiated presented a slight tendency to be higher than those obtained from non-irradiated carbon fibers

  10. Characterization of pyrolytic oil obtained from pyrolysis of TDF (Tire Derived Fuel)

    International Nuclear Information System (INIS)

    Banar, Müfide; Akyıldız, Vildan; Özkan, Aysun; Çokaygil, Zerrin; Onay, Özlem

    2012-01-01

    Highlights: ► We pyrolyzed Tire Derived Fuel (TDF) at different heating rates and temperatures. ► We determine convenient pyrolysis temperature for pyrolytic oil. ► The product can be used as fuel for combustion system in industry. ► TDF pyrolysis is advisable recycling system because of low hazardous constituents. - Abstract: In recent years, waste utilization before disposing to the land is the most important point about waste management. Due to the increasing emphasis on recycling, related to the two European Commission Directives (EC End of Life Vehicle Directive, EC Waste Landfill Directive) affecting the management of waste tires, there is interest in the development of alternative technologies for recycling waste tires. One of them is pyrolysis. For this purpose, a fixed bed reactor was used to pyrolysis of Tire Derived Fuel (TDF) at the temperatures of 350, 400, 450, 500, 550 and 600 °C with the heating rates of 5 and 35 °C/min. The maximum pyrolytic oil yield (38.8 wt.%) was obtained at 400 °C with 5 °C/min heating rate. The yield of pyrolytic oil decreased with increasing pyrolysis temperatures whereas the yield of gases increased. The fuel properties of the pyrolytic oil including higher heating value (HHV), elemental composition, flash point, viscosity, distillation and density were determined. Pyrolytic oil was characterized by fourier transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance spectroscopy ( 1 H NMR) and gas chromatography–mass spectroscopy (GC–MS) techniques and also, the amount of polychlorinated dibenzodioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) and congener distribution characteristics were studied for determination of environmental effects. It was seen that the pyrolytic oils have similar fuel properties with the diesel. It was also found that pyrolytic oil contained 0.00118 I-TEQs/g at very low level. Finally, the pyrolytic oil can be evaluated for energy recovery according to Regulation

  11. Electron beam influence on the carbon contamination of electron irradiated hydroxyapatite thin films

    International Nuclear Information System (INIS)

    Hristu, Radu; Stanciu, Stefan G.; Tranca, Denis E.; Stanciu, George A.

    2015-01-01

    Highlights: • Carbon contamination mechanisms of electron-beam-irradiated hydroxyapatite. • Atomic force microscopy phase imaging used to detect carbon contamination. • Carbon contamination dependence on electron energy, irradiation time, beam current. • Simulation of backscattered electrons confirms the experimental results. - Abstract: Electron beam irradiation which is considered a reliable method for tailoring the surface charge of hydroxyapatite is hindered by carbon contamination. Separating the effects of the carbon contamination from those of irradiation-induced trapped charge is important for a wide range of biological applications. In this work we focus on the understanding of the electron-beam-induced carbon contamination with special emphasis on the influence of the electron irradiation parameters on this phenomenon. Phase imaging in atomic force microscopy is used to evaluate the influence of electron energy, beam current and irradiation time on the shape and size of the resulted contamination patterns. Different processes involved in the carbon contamination of hydroxyapatite are discussed

  12. Regeneration of used activated carbon by electron beam irradiation

    International Nuclear Information System (INIS)

    Arai, H.; Hosono, M.; Zhu, G.; Miyata, T.

    1992-01-01

    The adsorbing power of granular activated carbons which adsorbed sodium laurylsulfate were most effectively recovered by irradiation of high energy electron beams in nitrogen stream, and the carbon was hardly lost by irradiation. The regeneration was induced mainly by microscopic heating of adsorption sites. Regeneration was also confirmed by adsorption endotherms. Regeneration cost was tentatively evaluated. (author)

  13. Improvement of carbon fiber surface properties using electron beam irradiation

    International Nuclear Information System (INIS)

    Pino, E.S.; Machado, L.D.B.; Giovedi, C.

    2007-01-01

    Carbon fiber-reinforced advance composites have been used for structural applications, mainly on account of their mechanical properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between its components, which are carbon fiber and polymeric matrix. The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite. EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests. Experimental results showed that EB irradiation improved the tensile strength of carbon fiber samples. The maximum value in tensile strength was reached using doses of about 250 kGy. After breakage, the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated. SEM micrographs showed modifications on the carbon fiber surface. (authors)

  14. Tritium permeation behavior through pyrolytic carbon in tritium production using high-temperature gas-cooled reactor for fusion reactors

    Directory of Open Access Journals (Sweden)

    H. Ushida

    2016-12-01

    Full Text Available Under tritium production method using a high-temperature gas-cooled reactor loaded Li compound, Li compound has to be coated by ceramic materials in order to suppress the spreading of tritium to the whole reactor. Pyrolytic carbon (PyC is a candidate of the coating material because of its high resistance for gas permeation. In this study, hydrogen permeation experiments using a PyC-coated isotropic graphite tube were conducted and hydrogen diffusivity, solubility and permeability were evaluated. Tritium permeation behavior through PyC-coated Li compound particles was simulated by using obtained data. Hydrogen permeation flux through PyC in a steady state is proportional to the hydrogen pressure and is larger than that through Al2O3 which is also candidate coating material. However, total tritium leak within the supposed reactor operation period through the PyC-coated Li compound particles is lower than that through the Al2O3-coated ones because the hydrogen absorption capacity in PyC is considerably larger than that in Al2O3.

  15. Carbon based prosthetic devices

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  16. High temperature SU-8 pyrolysis for fabrication of carbon electrodes

    DEFF Research Database (Denmark)

    Hassan, Yasmin Mohamed; Caviglia, Claudia; Hemanth, Suhith

    2017-01-01

    In this work, we present the investigation of the pyrolysis parameters at high temperature (1100 °C) for the fabrication of two-dimensional pyrolytic carbon electrodes. The electrodes were fabricated by pyrolysis of lithographically patterned negative epoxy based photoresist SU-8. A central...... composite experimental design was used to identify the influence of dwell time at the highest pyrolysis temperature and heating rate on electrical, electrochemical and structural properties of the pyrolytic carbon: Van der Pauw sheet resistance measurements, cyclic voltammetry, electrochemical impedance...... spectroscopy and Raman spectroscopy were used to characterize the pyrolytic carbon. The results show that the temperature increase from 900 °C to 1100 °C improves the electrical and electrochemical properties. At 1100 °C, longer dwell time leads to lower resistivity, while the variation of the pyrolysis...

  17. Aromatics extraction from pyrolytic sugars using ionic liquid to enhance sugar fermentability

    NARCIS (Netherlands)

    Li, X.; Luque-Moreno, L.C.; Oudenhoven, Stijn; Rehmann, L.; Kersten, Sascha R.A.; Schuur, Boelo

    2016-01-01

    Fermentative bioethanol production from pyrolytic sugars was improved via aromatics removal by liquid–liquid extraction. As solvents, the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide (P666,14[N(CN)2]) and ethyl acetate (EA) were compared. Two pyrolytic sugar solutions were created

  18. Calcium carbonate as a possible dosimeter for high irradiation doses

    International Nuclear Information System (INIS)

    Negron M, A.; Ramos B, S.; Camargo R, C.; Uribe, R. M.; Gomez V, V.; Kobayashi, K.

    2014-08-01

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  19. Calcium carbonate as a possible dosimeter for high irradiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Ramos B, S.; Camargo R, C. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M. [Kent State University, College of Technology, Kent OH (United States); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Kobayashi, K., E-mail: negron@nucleares.unam.mx [Yokohama National University (Japan)

    2014-08-15

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  20. The effect of gamma ray irradiation on PAN-based intermediate modulus carbon fibers

    International Nuclear Information System (INIS)

    Li, Bin; Feng, Yi; Qian, Gang; Zhang, Jingcheng; Zhuang, Zhong; Wang, Xianping

    2013-01-01

    Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were conducted on PAN-based intermediate modulus carbon fibers to investigate the structure and surface hydrophilicity of the carbon fibers before and after gamma irradiation. Two methods were used to determine Young’s modulus of the carbon fibers. The results show that gamma ray irradiation improved the degree of graphitization and introduced compressive stress into carbon fiber surface. Gamma ray also improved the carbon fiber surface hydrophilicity through increasing the value of O/C and enhancing the quantity of oxygen functional groups on carbon fibers. No distinct morphology change was observed after gamma ray irradiation. The Young’s modulus of the fibers increased with increasing irradiation dose

  1. Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrin

    NARCIS (Netherlands)

    Shen, J.; Kortlever, R.; Kas, Recep; Mul, Guido; Koper, M.T.M.

    2015-01-01

    The electrochemical conversion of carbon dioxide and water into useful products is a major challenge in facilitating a closed carbon cycle. Here we report a cobalt protoporphyrin immobilized on a pyrolytic graphite electrode that reduces carbon dioxide in an aqueous acidic solution at relatively low

  2. Graphitization kinetics of fluidized-bed pyrolytic carbons

    International Nuclear Information System (INIS)

    Beatty, R.L.

    1975-08-01

    Graphitization of 12 fluidized-bed pyrocarbons was studied as a function of heat-treatment time and temperature (1350 to 3000 0 C) to investigate the effect of initial microstructure on the graphitization process. The term ''graphitization'' is defined to include any thermally induced structural change, whether or not any layer stacking order is attained. A broad range of CVD microstructures was prepared at temperatures from 1150 to 1900 0 C and various propylene and methane concentrations. The twelve carbons spanned a wide range of graphitizabilities, primarily as a function of deposition temperature. Hydrocarbon concentration was of much less importance except for deposition at 1900 0 C. Hydrogen content of the as-deposited carbons decreased with increasing temperature of deposition, and initial graphitization behavior of the low-temperature carbons appeared to be related to hydrogen content and evolution. Rates of change in the parameters varied widely throughout the range of heat-treatment times (HTt) and temperatures (HTT) for the different carbons showing differences between the more graphitizable or ''soft'' carbons from the nongraphitizing or ''hard'' carbons. ΔH for nongraphitizing carbons was 175 +- 15 kcal below 1950 0 C, 240 +- 35 kcal at 1950 to 2700 0 C, and 330 +- 20 kcal above 2700 0 C. For graphitizing carbons deposited at 1150 0 C, values near 245 kcal were obtained from anti chi data for the HTT range 1350 to 1650 0 C, while densification data yielded values of about 160 kcal in the same range. The behaviors observed for graphitizable carbons above 2000 0 C are consistent with literature. Different kinetic behaviors below 2000 0 C were shown to be due to different initial microstructures as well as to different parameters measured. (U.S.)

  3. Fabrication of periodical surface structures by picosecond laser irradiation of carbon thin films: transformation of amorphous carbon in nanographite

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, C.; Dorcioman, G. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, Magurele RO-077125 (Romania); Bita, B. [National Institute for Research and Development in Microtechnologies, 126A Erou Iancu Nicolae Street, Voluntari RO-077190 (Romania); Faculty of Physics, 405 Atomistilor Street, Magurele RO-077125 (Romania); Besleaga, C.; Zgura, I. [National Institute of Materials Physics, 105bis Atomistilor Street, Magurele RO-077125 (Romania); Himcinschi, C. [Institute of Theoretical Physics, TU Bergakademie Freiberg, Freiberg D-09596 (Germany); Popescu, A.C., E-mail: andrei.popescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, Magurele RO-077125 (Romania)

    2016-12-30

    Highlights: • Ripples obtained on carbon films after irradiation with visible ps laser pulses. • Amorphous carbon was transformed in nanographite following irradiation. • Ripples had a complex morphology, being made of islands of smaller ripples. • Hydrophilic carbon films became hydrophobic after surface structuring. - Abstract: Thin films of carbon were synthesized by ns pulsed laser deposition in vacuum on silicon substrates, starting from graphite targets. Further on, the films were irradiated with a picosecond laser source emitting in visible at 532 nm. After tuning of laser parameters, we obtained a film surface covered by laser induced periodical surface structures (LIPSS). They were investigated by optical, scanning electron and atomic force microscopy. It was observed that changing the irradiation angle influences the LIPSS covered area. At high magnification it was revealed that the LIPSS pattern was quite complex, being composed of other small LIPSS islands, interconnected by bridges of nanoparticles. Raman spectra for the non-irradiated carbon films were typical for a-C type of diamond-like carbon, while the LIPSS spectra were characteristic to nano-graphite. The pristine carbon film was hydrophilic, while the LIPSS covered film surface was hydrophobic.

  4. A viable way to tailor carbon nanomaterials by irradiation-induced transformations

    International Nuclear Information System (INIS)

    Caudillo, R.; Troiani, H.E.; Miki-Yoshida, M.; Marques, M.A.L.; Rubio, A.; Yacaman, M.J.

    2005-01-01

    Since the discovery of carbon nanotubes (CNT), transmission electron microscopy (TEM) has been the most important tool in their investigation. It is possible to use electron irradiation in a TEM to construct a single-walled carbon nanotube (SWCNT) from an amorphous carbon film. Here we show that such a synthesis method creates a large number of carbon ad-atoms, which after some critical amount of radiation act to restore the system by reconstructing the carbon film. The behavior of the ad-atoms can be controlled by adjusting the current density in the microscope, suggesting that carbon nanomaterials can be tailored by electron irradiation

  5. EPR and UV spectrometry investigation of sucrose irradiated with carbon particles

    International Nuclear Information System (INIS)

    Karakirova, Yordanka; Yordanov, Nicola D.

    2010-01-01

    Solid state/EPR (SS/EPR) dosimeters of carbon ions irradiated sucrose are studied with EPR, and their water solutions - with UV spectroscopy. Doses between 20 and 200 Gy are used with linear energy transfer (LET) values for carbon ions of 63, 77, 96 and 230 keV μm -1 . After irradiation all samples show typical for irradiated sucrose EPR and UV spectra. The obtained data are compared with those previously reported for nitrogen particles and gamma rays irradiated sucrose. The identical shape of both the EPR and UV spectra of irradiated with various type radiation samples suggests that generated free radicals are not influenced by the nature of radiation. The lack of difference in the line width of the separate lines or the whole EPR spectrum, obtained for gamma and heavy particles irradiation, suggests negligible spin-spin interaction among the radiation-generated free radicals in the samples. The linear dependence of the EPR response on the absorbed dose radiation is found to be higher when generated by gamma rays, than by the same absorbed dose of heavy particles. In addition, the EPR response for carbon ions is higher than that for nitrogen ions. Water solutions of irradiated sucrose exhibit UV spectrum with absorption maximum at 267 nm, attributed to the recombination products of free radicals. The UV band intensity depends on the absorbed dose radiation. The UV spectra obtained for carbon, nitrogen and gamma rays irradiated sucrose are also compared.

  6. Pyrolytic 3D Carbon Microelectrodes for Electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Amato, Letizia

    2016-01-01

    electrochemical activity, chemical stability, and ease in surface functionalization [1]. The most common carbon microfabrication techniques (i.e. screen printing) produce two-dimensional (2D) electrodes, which limit the detection sensitivity. Hence several 3D microfabrication techniques have been explored......This work presents the fabrication and characterization of multi-layered three-dimensional (3D) pyrolysed carbon microelectrodes for electrochemical applications. For this purpose, an optimized UV photolithography and pyrolysis process with the negative tone photoresist SU-8 has been developed...... carbon [2]. This process enables fabrication of 2D and 3D electrodes with possibility for tailoring ad-hoc designs and unique sensitivities for specific applications. Due to this, pyrolysed carbon is becoming increasingly attractive for numerous applications, such as novel sensors and scaffolds for cell...

  7. The pyrolytic decomposition of o-, m-, and p-terphenyls and other potential reactor coolants

    Energy Technology Data Exchange (ETDEWEB)

    Juppe, G.; Hannaert, H.; Biver, F.

    1963-03-15

    Experiments were made on the pyrolytic decomposition of o-, m-, and p- terphenyls and mixtures of terphenyls with diphenyl. The effects of competing reactions were also studied by initially adding hydrogen, methane, ethane, propane, and benzene. The results indicate that the disappearance of o-, m-, and p-terphenyl seems to follow formally a first order reaction mechanism. The relative stability of the pure individual components increases in the order: oterphenyl (least stable), p-terphenyl, m-terphenyl (most stable). The activation energy was found to be in the neighborhood of 64 kcal/mole. The activation energy for the diphenyl formation during pyrolysis of an irradiated biphenyl-terphenyl mixture was found to be 47.9 kcal/mole. (P.C.H.)

  8. Irradiation-induced dimensional changes of poorly crystalline carbons

    International Nuclear Information System (INIS)

    Bullock, R.E.

    1979-01-01

    Data are presented on irradiation-induced changes of poorly crystalline carbons at high temperatures(>900 0 C). The materials surveyed include: (1) carbon fibers, (2) glassy carbons, (3) carbonaceous matrix materials for HTGR fuel rods and (4) pyrocarbons. The materials are listed in order of increasing stability, with maximum strains ranging from more than 50% for fibers to less than 10% for pyrocarbons. Dimensional changes of highly anisotropic carbon fibers appear to be sensitive to irradiation temperature, as slightly anisotropic pyrocarbons are, whereas temperature seems to have little influence on the behavior of isotropic glassy carbons over the range from 600 to 1350 0 C. Dimensional changes for graphite-filled matrix materials were roughly isotropic on the average and did not seem to be strongly temperature dependent for the lower fluences investigated. Increased graphite filler lowered volumetric dimensional changes of the matrix in agreement with a rule-of-mixtures relationship between change components for the filler and the less-stable binder phases. Instabilities of all of the poorly crystalline materials were generally greater than those for more crystalline carbons under the same conditions, including highly orientated graphites that approximate single-crystal behavior. (author)

  9. Experimental design for HTGR fuel rods

    International Nuclear Information System (INIS)

    Bayne, C.K.

    1975-01-01

    Fuel rods for the high temperature gas cooled reactor are composed of pyrolytic carbon coated fuel particles bounded by a carbonaceous matrix. Because of differential shrinkage between coated particles and the carbonaceous matrix, breakage of the pyrolytic coating has been observed with certain combinations of coated particles and matrix compositions. The pyrolytic coating is intended to be the primary containment for fission products. Therefore, an experiment is desired to determine the breakage characteristics of different strength coated particles combined with different matrix compositions during irradiation

  10. Low energy electron irradiation induced carbon etching: Triggering carbon film reacting with oxygen from SiO{sub 2} substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cheng [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Wang, Chao, E-mail: cwang367@szu.edu.cn, E-mail: dfdiao@szu.edu.cn; Diao, Dongfeng, E-mail: cwang367@szu.edu.cn, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2016-08-01

    We report low-energy (50–200 eV) electron irradiation induced etching of thin carbon films on a SiO{sub 2} substrate. The etching mechanism was interpreted that electron irradiation stimulated the dissociation of the carbon film and SiO{sub 2}, and then triggered the carbon film reacting with oxygen from the SiO{sub 2} substrate. A requirement for triggering the etching of the carbon film is that the incident electron penetrates through the whole carbon film, which is related to both irradiation energy and film thickness. This study provides a convenient electron-assisted etching with the precursor substrate, which sheds light on an efficient pathway to the fabrication of nanodevices and nanosurfaces.

  11. A guide to and review of the use of Multiwavelength Raman Spectroscopy for characterizing defective aromatic carbon solids : From graphene to amorphous carbons

    NARCIS (Netherlands)

    Merlen, A.; Buijnsters, J.G.; Pardanaud, C.

    2017-01-01

    sp2 hybridized carbons constitute a broad class of solid phases composed primarily of elemental carbon and can be either synthetic or naturally occurring. Some examples are graphite, chars, soot, graphene, carbon nanotubes, pyrolytic carbon, and diamond-like carbon. They vary from highly ordered to

  12. Binary Hierarchical Porous Graphene/Pyrolytic Carbon Nanocomposite Matrix Loaded with Sulfur as a High-Performance Li-S Battery Cathode.

    Science.gov (United States)

    Zhang, Hang; Gao, Qiuming; Qian, Weiwei; Xiao, Hong; Li, Zeyu; Ma, Li; Tian, Xuehui

    2018-06-06

    A N,O-codoped hierarchical porous nanocomposite consisting of binary reduced graphene oxide and pyrolytic carbon (rGO/PC) from chitosan is fabricated. The optimized rGO/PC possesses micropores with size distribution concentrated around 1.1 nm and plenty of meso/macropores. The Brunauer-Emmett-Teller specific surface area is 480.8 m 2 g -1 , and it possesses impressively large pore volume of 2.14 cm 3 g -1 . On the basis of the synergistic effects of the following main factors: (i) the confined space effect in the hierarchical porous binary carbonaceous matrix; (ii) the anchor effects by strong chemical bonds with codoped N and O atoms; and (iii) the good flexibility and conductivity of rGO, the rGO/PC/S holding 75 wt % S exhibits high performance as Li-S battery cathode. Specific capacity of 1625 mA h g -1 can be delivered at 0.1 C (1 C = 1675 mA g -1 ), whereas 848 mA h g -1 can be maintained after 300 cycles at 1 C. Even at high rate of 5 C, 412 mA h g -1 can be restrained after 1000 cycles.

  13. Application of Pyrolytic Carbon Derived from Carbonized-Biomass in AD/DSSCs%碳化生物质在AD/DSSCs中的应用

    Institute of Scientific and Technical Information of China (English)

    方雯; 云斯宁; 黄欣磊; 后玉芝; 朱江; 李雪

    2017-01-01

    As a renewable and clean energy, biogas and solar energy have attracted wide attention.In this paper, straw, leaves and corncob were carbonized by microwave pyrolytic carbonization technique, then, the carbonized-biomass were used as accelerant in anaerobic digestion (AD) and as counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs).The influence of the as-prepared carbon materials as accelerants on biogas production, chemical oxygen demand (COD) removing rate, pH value of the AD system and on the photovoltaic performance of DSSCs as CE catalysts was investigated, and further understanding the potential application of carbonized-biomass in the field of solar energy and biomass energy was discussed.Results indicate that, adding of carbonized-biomass as accelerant into anaerobic digestion system can obviously increase the biogas production (adding carbon materials 649 mL/g VS vs.control check 409 mL/g VS), improve the COD removing rate (adding carbon materials 68.00 % vs.control check 29.55 %), but has no effect on the pH value of the biogas AD system.The photoelectric conversion efficiency (PCE) of DSSCs using the carbonized-biomass is close to the traditional Pt electrode under the same condition (3.52% vs. 4.64%).The as-prepared carbon materials can be used as low-cost materials instead of Pt in DSSCs.%沼气和太阳能作为一种清洁的可再生能源已引起人们广泛的关注.以麦秆、树叶和玉米芯为原料,将其进行微波热解碳化,并将碳化产物分别作为促进剂和对电极催化剂应用于厌氧发酵(Anaerobic Digestion, AD)和染料敏化太阳能电池(Dye-Sensitized Solar Cells, DSSCs)中,研究其对沼气厌氧发酵系统的产气量、化学需氧量(Chemical Oxygen Demand, COD)去除率、pH和DSSCs光伏性能的影响,探究其在太阳能和生物质能领域的应用潜能.实验结果表明:碳化生物质作为厌氧发酵促进剂可明显提高沼气产量(添加碳材料549 mL/g VS vs.

  14. Temperature annealing of tracks induced by ion irradiation of graphite

    International Nuclear Information System (INIS)

    Liu, J.; Yao, H.J.; Sun, Y.M.; Duan, J.L.; Hou, M.D.; Mo, D.; Wang, Z.G.; Jin, Y.F.; Abe, H.; Li, Z.C.; Sekimura, N.

    2006-01-01

    Highly oriented pyrolytic graphite (HOPG) samples were irradiated by Xe ions of initial kinetic energy of 3 MeV/u. The irradiations were performed at temperatures of 500 and 800 K. Scanning tunneling microscopy (STM) images show that the tracks occasionally have elongated structures under high-temperature irradiation. The track creation yield at 800 K is by three orders of magnitude smaller compared to that obtained during room-temperature irradiation. STM and Raman spectra show that amorphization occurs in graphite samples irradiated at 500 K to higher fluences, but not at 800 K. The obtained experimental results clearly reveal that the irradiation under high temperature causes track annealing

  15. Bending of metal-filled carbon nanotube under electron beam irradiation

    Directory of Open Access Journals (Sweden)

    Abha Misra

    2012-03-01

    Full Text Available Electron beam irradiation induced, bending of Iron filled, multiwalled carbon nanotubes is reported. Bending of both the carbon nanotube and the Iron contained within the core was achieved using two approaches with the aid of a high resolution electron microscope (HRTEM. In the first approach, bending of the nanotube structure results in response to the irradiation of a pristine kink defect site, while in the second approach, disordered sites induce bending by focusing the electron beam on the graphite walls. The HRTEM based in situ observations demonstrate the potential for using electron beam irradiation to investigate and manipulate the physical properties of confined nanoscale structures.

  16. The influence of fractionation on cell survival and premature differentiation after carbon ion irradiation

    International Nuclear Information System (INIS)

    Wang Jufang; Li Renming; Guo Chuanling; Fournier, C.; K-Weyrather, W.

    2008-01-01

    To investigate the influence of fractionation on cell survival and radiation induced premature differentiation as markers for early and late effects after X-rays and carbon irradiation. Normal human fibroblasts NHDF, AG1522B and WI-38 were irradiated with 250 kV X-rays, or 266 MeV/u, 195 MeV/u and 11 MeV/u carbon ions. Cytotoxicity was measured by a clonogenic survival assay or by determination of the differentiation pattern. Experiments with high-energy carbon ions show that fractionation induced repair effects are similar to photon irradiation. The relative biological effective (RBE) 10 values for clonogenic survival are 1.3 and 1.6 for irradiation in one or two fractions for NHDF cells and around 1.2 for AG1522B cells regardless of the fractionation scheme. The RBE for a doubling of post mitotic fibroblasts (PMF) in the population is 1 for both single and two fractionated irradiation of NHDF cells. Using 11 MeV/u carbon ions, no repair effect can be seen in WI-38 cells. The RBE 10 for clonogenic survival is 3.2 for single irradiation and 4.9 for two fractionated irradiations. The RBE for a doubling of PMF is 3.1 and 5.0 for single and two fractionated irradiations, respectively. For both cell lines the effects of high-energy carbon ions representing the irradiation of the skin and the normal tissue in the entrance channel are similar to the effects of X-rays. The fractionation effects are maintained. For the lower energy, which is representative for the irradiation of the tumor region, RBE is enhanced for clonogenic survival as well as for premature terminal differentiation. Fractionation effects are not detectable. Consequently, the therapeutic ratio is significantly enhanced by fractionated irradiation with carbon ions. (author)

  17. Pseudo-topotactic conversion of carbon nanotubes to T-carbon nanowires under picosecond laser irradiation in methanol.

    Science.gov (United States)

    Zhang, Jinying; Wang, Rui; Zhu, Xi; Pan, Aifei; Han, Chenxiao; Li, Xin; Dan Zhao; Ma, Chuansheng; Wang, Wenjun; Su, Haibin; Niu, Chunming

    2017-09-25

    Pseudo-topotactic conversion of carbon nanotubes into one-dimensional carbon nanowires is a challenging but feasible path to obtain desired diameters and morphologies. Here, a previously predicted but experimentally unobserved carbon allotrope, T-carbon, has been produced from pseudo-topotactic conversion of a multi-walled carbon nanotube suspension in methanol by picosecond pulsed-laser irradiation. The as-grown T-carbon nanowires have the same diameter distribution as pristine carbon nanotubes, and have been characterized by high-resolution transmission electron microscopy, fast Fourier transform, electron energy loss, ultraviolet-visible, and photoluminescence spectroscopies to possess a diamond-like lattice, where each carbon is replaced by a carbon tetrahedron, and a lattice constant of 7.80 Å. The change in entropy from carbon nanotubes to T-carbon reveals the phase transformation to be first order in nature. The computed electronic band structures and projected density of states are in good agreement with the optical absorption and photoluminescence spectra of the T-carbon nanowires.T-carbon is a previously predicted but so far unobserved allotrope of carbon, with a crystal structure similar to diamond, but with each atomic lattice position replaced by a carbon tetrahedron. Here, the authors produce T-carbon nanowires via laser-irradiating a suspension of carbon nanotubes in methanol.

  18. The proliferative response of mouse intestinal crypts during fractionated irradiation of carbon beams

    International Nuclear Information System (INIS)

    Abo, M.; Abe, Y.; Mariya, Y.; Ando, K.

    2000-01-01

    Clonogenic assay of jejunal crypt during carbon beam and X-ray irradiations was performed. Fractionation with top-up dose assay revealed carbon beam irradiations caused more damage than X-ray did. To clarify this problem is urgent. (author)

  19. Carbon nanotubes polymerization induced by self-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Cassio Stein [Faculdade de Fisica, Pontificia Univ. Catolica do Rio Grande do Sul (PUCRS), Porto Alegre (Brazil)

    2008-07-01

    Full text: We discuss our recent results on the formation of cross-links between neighboring carbon nanotubes within a bundle. Classical molecular dynamics was used to follow the evolution of the system when it is bombarded by low-energy carbon atoms. We show that it is possible to polymerize carbon nanotubes through irradiation and discuss the most common types of defects produced. Cross-links are created mainly in the direction perpendicular to the surface, and for higher energies, defects are created deeper in the rope. The final defects geometries may provide a realistic input to electronic density first principle calculations. (author)

  20. Carbon nanotubes polymerization induced by self-irradiation

    International Nuclear Information System (INIS)

    Moura, Cassio Stein

    2008-01-01

    Full text: We discuss our recent results on the formation of cross-links between neighboring carbon nanotubes within a bundle. Classical molecular dynamics was used to follow the evolution of the system when it is bombarded by low-energy carbon atoms. We show that it is possible to polymerize carbon nanotubes through irradiation and discuss the most common types of defects produced. Cross-links are created mainly in the direction perpendicular to the surface, and for higher energies, defects are created deeper in the rope. The final defects geometries may provide a realistic input to electronic density first principle calculations. (author)

  1. Low-energy electron irradiation induced top-surface nanocrystallization of amorphous carbon film

    Science.gov (United States)

    Chen, Cheng; Fan, Xue; Diao, Dongfeng

    2016-10-01

    We report a low-energy electron irradiation method to nanocrystallize the top-surface of amorphous carbon film in electron cyclotron resonance plasma system. The nanostructure evolution of the carbon film as a function of electron irradiation density and time was examined by transmission electron microscope (TEM) and Raman spectroscopy. The results showed that the electron irradiation gave rise to the formation of sp2 nanocrystallites in the film top-surface within 4 nm thickness. The formation of sp2 nanocrystallite was ascribed to the inelastic electron scattering in the top-surface of carbon film. The frictional property of low-energy electron irradiated film was measured by a pin-on-disk tribometer. The sp2 nanocrystallized top-surface induced a lower friction coefficient than that of the original pure amorphous film. This method enables a convenient nanocrystallization of amorphous surface.

  2. Neutron irradiation effects on the mechanical properties of thorium and thorium--carbon alloy

    International Nuclear Information System (INIS)

    Wang, S.C.P.

    1978-04-01

    The effects of neutron exposure to 3.0 x 10 18 neutrons/cm 2 on the mechanical properties of thorium and thorium-carbon alloy are described. Tensile measurements were done at six different test temperatures from 4 0 K to 503 0 K and at two strain rates. Thorium and thorium-carbon alloy are shown to display typical radiation hardening like other face-centered cubic metals. The yield drop phenomenon of the thorium-carbon alloy is unchanged after irradiation. The variation of shear stress and effective shear stress with test temperature was fitted to Seeger's and Fleischer's equations for irradiated and unirradiated thorium and thorium-carbon alloy. Neutron irradiation apparently contributes an athermal component to the yield strength. However, some thermal component is detected in the low temperature range. Strain-rate parameter is increased and activation volume is decreased slightly for both kinds of metal after irradiation

  3. Formation of carbon nano- and micro-structures on C+1 irradiated copper surfaces

    International Nuclear Information System (INIS)

    Ahmad, Shoaib

    2013-01-01

    A series of experiments has identified mechanisms of carbon nano- and micro-structure formation at room temperature, without catalyst and in the environment of immiscible metallic surroundings. The structures include threaded nano fibres, graphitic sheets and carbon onions. Copper as substrate was used due to its immiscibility with carbon. Energetic carbon ions (C + 1 ) of 0.2–2.0 MeV irradiated Cu targets. Cu substrates, apertures and 3 mm dia TEM Cu grids were implanted with the carbon. We observed wide range of μm-size structures formed on Cu grids and along the edges of the irradiated apertures. These are shown to be threaded nano fibers (TNF) of few μm thicknesses with lengths varying from 10 to 3000 μm. Secondary electron microscopy (SEM) identifies the μm-size structures while Confocal microscopy was used to learn about the mechanisms by which C + 1 irradiated Cu provides the growth environment. Huge carbon onions of diameters ranging from hundreds of nm to μm were observed in the as-grown and annealed samples. Transformations of the nanostructures were observed under prolonged electron irradiations of SEM and TEM. A mechanism for the formation of carbon nano- and micro-structures is proposed.

  4. The effect of neutron irradiation on the trapping of tritium in carbon-based materials

    International Nuclear Information System (INIS)

    Kwast, H.; Werle, H.; Glugla, M.; Wu, C.H.; Federici, G.

    1993-11-01

    Carbon-based materials are considered for protection of plasma facing components in the next step fusion device. To investigate the effects of neutron damage on the tritium behaviour an experimental study on the tritium retention of various neutron irradiated graphites and carbon/carbon fibre composites was started. The irradiation dose of the specimens ranges from 10 -3 to 3.5 dpa.g and the irradiation temperature from 390 C to 1500 C. A comparison of tritium retention in pre- and post-irradiated carbon-based materials as a function of the sample temperature is reported in this paper and the results are discussed. The first results indicate that the retention of tritium is higher in irradiated graphite than in unirradiated graphite and depends largely on the density and microstructure. The retention is also influenced by the tritium-loading temperature. Graphite of type S 1611, irradiated at 400 C and 600 C up to a damage of 0.1 dpa.g, retained about two times more tritium than the unirradiated material. (orig.)

  5. Effects of main traits of sweet sorghum irradiated by carbon ions

    International Nuclear Information System (INIS)

    Li Wenjian; He Jingyu; Liu Qingfang; Yu Lixia; Dong Xicun

    2009-01-01

    To investigate the influence of carbon ion irradiation on important agronomic characters of sweet sorghum, dry seeds of Sweet Sorghum BJ0601 and BJ0602 were irradiated by 100 MeV/u 12 C +6 ion beam to different doses at Heavy Ion Accelerator National Laboratory in Lanzhou (HIANLL). When matured, the main traits of sweet sorghum were measured. The correlation coefficient of five main agronomic characters, i.e. number of node, plant height, stalk diameter, sugar content and stem weight per plant, were analyzed using the SPSS 13.0 software. The results indicated that the obvious influence of sweet sorghum irradiated by carbon ion beam was observed. In addition, the correlation of main traits was studied. This study may provide rudimental data to select novel variety of sweet sorghum suited for fuel ethanol production. In addition, the average of sugar content of early mutant BJ0601-1 is higher than BJ0601 in M2, and the sugar content of sweet sorghum may be improved by carbon ion beam irradiation. (authors)

  6. Hydrogen Transfer from Hantzsch 1,4-Dihydropyridines to Carbon-Carbon Double Bonds under Microwave Irradiation

    OpenAIRE

    Jean Jacques Vanden Eynde; Didier Barbry; Guy Cordonnier; Séverine Torchy

    2002-01-01

    1,4-Dihydropyridines (DHPs) have been used in the reduction of carbon-carbon double bonds under microwave irradiation without solvent. The efficiency of the reactions is dramatically dependent on the steric effects in the DHPs and on the electronic effects in the olefins.

  7. Process to minimize cracking of pyrolytic carbon coatings

    Science.gov (United States)

    Lackey, Jr., Walter J.; Sease, John D.

    1978-01-01

    Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.

  8. Radioprotective effects of melatonin on carbon-ion and X ray irradiation in mice

    International Nuclear Information System (INIS)

    Saito, Masayoshi; Kawata, Tetsuya; Liu, C.; Sakurai, Akiko; Ito, Hisao; Ando, Koichi

    2004-01-01

    The radioprotective ability of melatonin was investigated in C3H mice irradiated to a whole-body X-ray (150 Kv, 20 mA) and carbon-ion (290 MeV/u). Mice exposed to X-ray, 13 KeV/μm and 50 KeV/μm carbon-ion dose of 7.0-7.5 Gy, 6.5-7.25 Gy and 6.0-6.5 Gy, respectively. One hour before the irradiation, mice were given an intraperitoneal injection of 0.2 ml of either solvent (soybean oil) or melatonin (250 mg/kg, uniform suspension in soybean oil). Mice were observed for mortality over a period of 30 days following irradiation. Results obtained the first year are as follows. The toxicity of melatonin (at a dose 250 mg/kg) intraperitoneal administered to mice could not be observed. A pretreatment of melatonin is effective in protecting mice from lethal damage of low-linear energy transfer (LET) irradiation (X-ray and 13 KeV/μm carbon-ion). In the high-LET irradiated mice with 50 KeV/μm carbon-ion, melatonin exhibited a slight increase in their survival. (author)

  9. Optimising carbon electrode materials for adsorptive stripping voltammetry

    OpenAIRE

    Chaisiwamongkhol, K; Batchelor-McAuley, C; Sokolov, S; Holter, J; Young, N; Compton, R

    2017-01-01

    Different types of carbon electrode materials for adsorptive stripping voltammetry are studied through the use of cyclic voltammetry. Capsaicin is utilised as a model compound for adsorptive stripping voltammetry using unmodified and modified basal plane pyrolytic graphite (BPPG) electrodes modified with multi-walled carbon nanotubes, carbon black or graphene nanoplatelets, screen printed carbon electrodes (SPE), carbon nanotube modified screen printed electrodes, and carbon paste electrodes....

  10. High-temperature properties of commercial pyrolytic graphite

    International Nuclear Information System (INIS)

    Goetzel, C.G.

    1979-01-01

    Pyrolytic graphite is produced commercially as free-standing massive structures of continuously-nucleated and surface-nucleated varieties. Both are used for rocket nozzle components. The major design-significant thermal and mechanical properties of both material types are presented as a function of temperature up to 3000 K. They are compared with each other and with previous data. (author)

  11. Yield and nutrient composition of biochar produced from different feedstocks at varying pyrolytic temperatures

    International Nuclear Information System (INIS)

    Naeem, M.A.; Khalid, M.; Arshad, M.; Ahmad, R.

    2014-01-01

    Variation in pyrolytic temperatures and feedstocks affects the yield and nutrient composition of biochar. Selection of suitable feedstock and optimum pyrolytic temperature is crucial before using it for agricultural purposes. We compared biochars produced from two feedstocks (wheat straw and rice) at three temperatures (300, 400 and 500 degree C). Biochar yield decreased significantly (p<0.05) with increasing pyrolysis temperature, while ash contents were increased. The cation exchange capacity was significantly higher (119 cmolc kg/sup -1/) at temperature 400 degree C. The pH, electrical conductivity (EC) and carbon content of biochars increased significantly with increasing temperature and maximum pH (10.4) and EC (3.35 dS m/sup -1/) were observed in rice straw biochar (WSB) at 500 degree C and carbon content (662 g kg/sup -1/) in wheat straw biochar (RSB) at 500 degree C. Concentration of phosphorus (P) and potassium (K) increased significantly with increasing temperature, while of nitrogen (N) decreased. Overall, the maximum N (13.8 g kg/sup -1/at 300 degree C) and P (3.4 g kg/sup -1/at 500 degree C) concentrations were observed in WSB while, maximum K (48 g kg/sup -1/ at 500 degree C)in RSB. High pyrolysis temperature reduced AB-DTPA extractable nutrients (expect Mn). The highest AB-DTPA extractable nutrients such as P (113 mg kg/sup -1/) and Ca (1.07 g kg/sup -1/) were observed in WSB at 300 degree C while, K (18 g kg/sup -1/) and magnesium (Mg) (1.55 g kg/sup -1/) in RSB at 300 degree C. Selected feedstock and use of low pyrolysis temperature may produce nutrient-rich biochar, with high CEC and low pH and these could have positive effects on calcareous soils. (author)

  12. Formation of glassy carbon structure and its change under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kurolenkin, E.I.; Lopato, Yu.S.; Virgil' ev, Yu.S.; Khakimova, D.K.; Aksenov, S.I.

    1981-01-01

    The changes of glassy carbon structure, which is prepared of phenol-formaldehyde and furfurol-phenol-formaldehyde resins in the process of irradiation with 5.3x10/sup 20/ cm/sup -2/ neutron fluence with the energy E>0.18 MeV in the temperature range of 90-540 deg C are studied. It is established the irradiation results in the shrinkage of the samples. The compression of the samples increases with the irradiation temperature and neutron fluence. The thermal annealing does not result in the restoration of the volume of samples. The sample shrinkage, caused by more compact package of globular structures and the destruction of film structures, decrease gas permeability of glassy carbon.

  13. Constructing carbon nanotube junctions by Ar ion beam irradiation

    International Nuclear Information System (INIS)

    Ishaq, Ahmad; Ni Zhichun; Yan Long; Gong Jinlong; Zhu Dezhang

    2010-01-01

    Carbon nanotubes (CNTs) irradiated by Ar ion beams at elevated temperature were studied. The irradiation-induced defects in CNTs are greatly reduced by elevated temperature. Moreover, the two types of CNT junctions, the crossing junction and the parallel junction, were formed. And the CNT networks may be fabricated by the two types of CNT junctions. The formation process and the corresponding mechanism of CNT networks are discussed.

  14. The early effects in the brain after irradiation with carbon ions using mice

    International Nuclear Information System (INIS)

    Takai, Nobuhiko; Nakamura, Saori; Ohba, Yoshihito; Uzawa, Akiko; Furusawa, Yoshiya; Koike, Sachiko; Matsumoto, Yoshitaka; Hirayama, Ryoichi

    2011-01-01

    This study investigated both early and late effects in the brain after irradiation with carbon ions using mice. The irradiation dose was set at level known to produce vascular change followed by necrosis, which appeared the late period after irradiation with 30 Gy. The whole of brain was irradiated, excluding eyes and brain stem. The mice irradiated with single dose of 30 Gy showed deficit in short-term working memory assessed at 36 hr after irradiation, whereas mice receiving carbon irradiation showed no deficit in long-term reference memory. At 16 weeks after irradiation, the irradiated mice showed marked learning impairment compared with age-matched controls and the irradiated mice showed substantial impairment of working memory. Histopathological observation revealed no abnormal finding in the irradiated brain at 36 hr after irradiation, although irradiated mice showed marked neuronal degeneration at the hippocampus within CA1 to CA3 layers at 16 weeks after irradiation. In the irradiated group, neuronal cells in the hippocampal CA1-3 areas were reduced by 30-49%. These results suggest that although irradiation-induced hippocampal degeneration is associated with learning disability, cognitive deficits may also be detected on the early stage, not associated with hippocampal degeneration. (author)

  15. Enhancement of SPHK1 in vitro by carbon ion irradiation in oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Higo, Morihiro; Uzawa, Katsuhiro; Kawata, Tetsuya; Kato, Yoshikuni; Kouzu, Yukinao; Yamamoto, Nobuharu; Shibahara, Takahiko; Mizoe, Jun-etsu; Ito, Hisao; Tsujii, Hirohiko; Tanzawa, Hideki

    2006-01-01

    Purpose The purpose of this study was to assess the gene expression changes in oral squamous cell carcinoma (OSCC) cells after carbon ion irradiation. Methods and Materials Three OSCC cell lines (HSC2, Ca9-22, and HSC3) were irradiated with accelerated carbon ion beams or X-rays using three different doses. The cellular sensitivities were determined by clonogenic survival assay. To identify genes the expression of which is influenced by carbon ion irradiation in a dose-dependent manner, we performed Affymetrix GeneChip analysis with HG-U133 plus 2.0 arrays containing 54,675 probe sets. The identified genes were analyzed using the Ingenuity Pathway Analysis Tool to investigate the functional network and gene ontology. Changes in mRNA expression in the genes were assessed by real-time reverse transcriptase-polymerase chain reaction. Results We identified 98 genes with expression levels that were altered significantly at least twofold in each of the three carbon-irradiated OSCC cell lines at all dose points compared with nonirradiated control cells. Among these, SPHK1, the expression of which was significantly upregulated by carbon ion irradiation, was modulated little by X-rays. The function of SPHK1 related to cellular growth and proliferation had the highest p value (p = 9.25e-7 to 2.19e-2). Real-time reverse transcriptase-polymerase chain reaction analysis showed significantly elevated SPHK1 expression levels after carbon ion irradiation (p < 0.05), consistent with microarray data. Clonogenic survival assay indicated that carbon ion irradiation could induce cell death in Ca9-22 cells more effectively than X-rays. Conclusions Our findings suggest that SPHK1 helps to elucidate the molecular mechanisms and processes underlying the biologic response to carbon ion beams in OSCC

  16. Impairments of DNA synthesization and normal tissue after irradiation with carbon ions

    International Nuclear Information System (INIS)

    Takai, Nobuhiko; Watanabe, Masahiko; Ando, Koichi; Furusawa, Yoshiya; Uzawa, Akiko; Koike, Sachiko; Fukawa, Takeshi; Monobe, Manami; Hirayama, Ryoichi

    2006-01-01

    The purpose of this study is to evaluate [2- 14 C]thymidine as a tracer, to detect radiation damages in gut. We examined the radiolabeled thymidine accumulation in gut after irradiated with carbon-ion. Mice were given whole body irradiation with carbon-ion (290 MeV/u, 6 cm-spread-out Bragg peak (SOBP), 20 keV/μm). Gut [2- 14 C]thymidine accumulation significantly decreased 4 hr after irradiated with 9 Gy, and did not recover until 24 hr after irradiation. Furthermore, we investigated the dose dependency of [2- 14 C]thymidine accumulation in gut. At 12 hr after irradiation, accumulation of thymidine decreased with an increase of carbon-ion doses (1-9 Gy), whereas that of [6- 3 H]thymidine was independent of radiation dose. These results suggest that the difference of isotope-labeled position causes change of thymidine kinetics. At 84 hr after irradiation, [2- 14 C]thymidine accumulation showed no dose dependence. However, a clear dose dependence was obtained when [2- 14 C]thymidine accumulation was corrected by blood flow. Uptake of a regional blood flow marker 14 C-N-isopropyl-p-iodoamphetamine (IMP) in gut increased after 9-18 Gy irradiation. These findings demonstrated that the [2- 14 C]thymidine uptake in vivo could be an appropriate marker for investigating gut responses and blood flow should be taken account for the evaluation by [2- 14 C]thymidine. (author)

  17. Electron beam irradiation effects on carbon fiber reinforced PEEK composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Hagiwara, Miyuki; Odajima, Tosikazu; Sakai, Hideo; Nakakura, Toshiyuki; Masutani, Masahiro.

    1987-03-01

    Carbon fiber(CF) reinforced composites, using polyarylether-sulfone (PES) or polyarylether-ether-ketone (PEEK) as matrix material, were prepared and their electron beam irradiation effects were studied on the basis of changes in mechanical and dynamic viscoelastic properties and observation of fracture surfaces. The flexural strength of PES-CF composite decreased to 70 % of the initial strength after the irradiation of 3 MGy and 40 % after 15 MGy. The change in the profile of stress-strain (S-S) curves and fractographic observation by electron microscopy indicated that this composite irradiated with over 3 MGy was fractured by delamination caused by to the degradation of matrix polymer. The mechanical properties of PEEK-CF composite were scarcely decreased even after irradiated up to 180 MGy and this composite showed very high radiation resistance. The change in the profile of S-S curves and fractographic observation showed that this composite fractured due to destruction of fiber in the dose range less than 180 MGy, indicating that PEEK was excellent matrix material used in high radiation field. PEEK-PES-CF composite which was composed of the carbon fibers coated with PES solution showed less radiation resistance compared with PEEK-CF composite; the flexural strength decreased to 85 % of the initial value after the irradiation with 90 MGy. It was revealed from the changes in the profile of S-S curve that the specimen irradiated over 120 MGy was fractured due to not only fiber destruction but delamination. Deterioration mechanism of PEEK-PES-CF composite was studied by dynamic viscoelastic measurements in connection with the damage on matrix-fiber interface. It was suggested that the deterioration in mechanical properties of this composite was caused by the degradation of PES that coated on the surface of the carbon fibers. (author)

  18. DNA damage response signaling in lung adenocarcinoma A549 cells following gamma and carbon beam irradiation.

    Science.gov (United States)

    Ghosh, Somnath; Narang, Himanshi; Sarma, Asitikantha; Krishna, Malini

    2011-11-01

    Carbon beams (5.16MeV/u, LET=290keV/μm) are high linear energy transfer (LET) radiation characterized by higher relative biological effectiveness than low LET radiation. The aim of the current study was to determine the signaling differences between γ-rays and carbon ion-irradiation. A549 cells were irradiated with 1Gy carbon or γ-rays. Carbon beam was found to be three times more cytotoxic than γ-rays despite the fact that the numbers of γ-H2AX foci were same. Percentage of cells showing ATM/ATR foci were more with γ-rays however number of foci per cell were more in case of carbon irradiation. Large BRCA1 foci were found in all carbon irradiated cells unlike γ-rays irradiated cells and prosurvival ERK pathway was activated after γ-rays irradiation but not carbon. The noteworthy finding of this study is the early phase apoptosis induction by carbon ions. In the present study in A549 lung adenocarcinoma, authors conclude that despite activation of same repair molecules such as ATM and BRCA1, differences in low and high LET damage responses might be due to their distinct macromolecular complexes rather than their individual activation and the activation of cytoplasmic pathways such as ERK, whether it applies to all the cell lines need to be further explored. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Irradiation-induced defects in graphite and glassy carbon studied by positron annihilation

    International Nuclear Information System (INIS)

    Hasegawa, M.; Kajino, M.; Kuwahara, H.; Yamaguchi, S.; Kuramoto, E.; Takenaka, M.

    1992-01-01

    ACAR and positron lifetime measurements have been made on, HOPG, isotropic fine-grained graphites, glassy carbons and C 60 /C 70 . HOPG showed a marked bimodal ACAR distribution along the c-axis. By irradiation of 1.0 X 10 19 fast neutrons/cm 2 remarkable narrowing in the ACAR curves and disappearance of the bimodal distribution were observed. Lifetime in HOPG increased from 225 psec to 289 psec (positron-lifetime in vacancies and their small clusters) by the irradiation. The irradiation on isotropic graphites and glassy carbons, however, gave slight narrowing in ACAR curves and decrease in lifetimes (360 psec → 300psec). This suggests irradiation-induced vacancy trapping in crystallites. In C 60 /C 70 powder two lifetime components were detected: τ 1 =177psec, τ 2 =403psec (I 2 =58%). The former is less than the bulk lifetime of HOPG, while the latter being very close to lifetimes in the isotropic graphites and glassy carbons. This and recent 2D-ACAR study of HOPG surface [15] strongly suggest free and defect surface states around ''soccer ball'' cages

  20. Enhanced electromagnetic properties of nickel nanoparticiles dispersed carbon fiber via electron beam irradiation

    International Nuclear Information System (INIS)

    Lee, Yeong Ju; Kim, Hyun Bin; Lee, Seung Jun; Kang, Phil Hyun

    2015-01-01

    Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications

  1. Enhanced electromagnetic properties of nickel nanoparticiles dispersed carbon fiber via electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeong Ju; Kim, Hyun Bin; Lee, Seung Jun; Kang, Phil Hyun [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2015-02-15

    Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications.

  2. Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

    Science.gov (United States)

    Makowiecki, Daniel M.; Ramsey, Philip B.; Juntz, Robert S.

    1995-01-01

    An improved method for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite's high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding.

  3. Effects of temperature during the irradiation of calcium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Camargo R, C.; Ramos B, S. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M., E-mail: negron@nucleares.unam.mx [Kent State University, College of Technology, Kent 44240 Ohio (United States)

    2015-10-15

    The gamma irradiation of calcium carbonate at different doses (0 to 309 kGy) and temperature regimes (77 K to 298 K) was carried out to study the effects of irradiation temperature. The changes were followed by EPR spectroscopy. We observed the formation of a composite EPR spectrum even at low radiation doses and temperature. There is a strong effect on the evaluation of the radicals formed as a function of irradiation temperature, probably due to the diffusion in the frozen powder. Response curves show that this system tends to saturate at 10 MGy at 298 K. (Author)

  4. Effects of temperature during the irradiation of calcium carbonate

    International Nuclear Information System (INIS)

    Negron M, A.; Camargo R, C.; Ramos B, S.; Gomez V, V.; Uribe, R. M.

    2015-10-01

    The gamma irradiation of calcium carbonate at different doses (0 to 309 kGy) and temperature regimes (77 K to 298 K) was carried out to study the effects of irradiation temperature. The changes were followed by EPR spectroscopy. We observed the formation of a composite EPR spectrum even at low radiation doses and temperature. There is a strong effect on the evaluation of the radicals formed as a function of irradiation temperature, probably due to the diffusion in the frozen powder. Response curves show that this system tends to saturate at 10 MGy at 298 K. (Author)

  5. Carbon-ion beam irradiation kills X-ray-resistant p53-null cancer cells by inducing mitotic catastrophe.

    Directory of Open Access Journals (Sweden)

    Napapat Amornwichet

    Full Text Available BACKGROUND AND PURPOSE: To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies. MATERIALS AND METHODS: DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs by immunostaining of phosphorylated H2AX (γH2AX, and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3. RESULTS: The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation. CONCLUSIONS: Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment.

  6. Equipment for lustrous carbon determination

    Directory of Open Access Journals (Sweden)

    A. Witowski

    2008-07-01

    Full Text Available In this paper methods of determination of total pyrolytic carbon and its fraction: lustrous and amorphous carbon was shown. They are used in foundry industry as carbonaceous materials, i.e. in coal dust replacements and moulding sands. The principle of model analyser working, which uses NDIR module detection, and example results of such analysis were also presented.

  7. Effect of neutron irradiation on the dimension and the strength of carbon fiber/carbon composite derived from thermosetting resin precursor

    International Nuclear Information System (INIS)

    Yasuda, Eiichi; Tanabe, Yasuhiro; Kimura, Shiushichi; Maruyama, Tadashi; Iseki, Takayoshi; Yano, Toyohiko.

    1988-01-01

    Unidirectionally reinforced carbon fiber/carbon composite whose matrix was derived from thermosetting resin, was prepared. The heat-treatment temperature was 2800 deg C. The change in size and 4 point bending strength of the composite was measured after neutron irradiation (640 deg C, 6 x 10 24 n/m 2 , E > 1 MeV). Shrinkage in normal to the fiber direction was larger than that in fiber direction. Increase in strength and Young's modulus of the composite was observed after irradiation. Irradiated composite showed much higher deflection to fracture than unirradiated one. (author)

  8. Fabrication of carbon layer coated FE-nanoparticles using an electron beam irradiation

    Science.gov (United States)

    Kim, Hyun Bin; Jeun, Joon Pyo; Kang, Phil Hyun; Oh, Seung-Hwan

    2016-01-01

    A novel synthesis of carbon encapsulated Fe nanoparticles was developed in this study. Fe chloride (III) and polyacrylonitrile (PAN) were used as precursors. The crosslinking of PAN molecules and the nucleation of Fe nanoparticles were controlled by the electron beam irradiation dose. Stabilization and carbonization processes were carried out using a vacuum furnace at 275 °C and 1000 °C, respectively. Micro structures were evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fe nanoparticles were formed with diameters of 100 nm, and the Fe nanoparticles were encapsulated by carbon layers. As the electron beam irradiation dose increased, it was observed that the particle sizes decreased.

  9. The vacuum pyrolysis of used tires. End-uses for oil and carbon black products

    Energy Technology Data Exchange (ETDEWEB)

    Roy, C.; Chaala, A.; Darmstadt, H. [Institut Pyrovac Inc., Parc Technologique du Quebec Metropolitain, rue Franquet, Sainte-Foy (Canada)

    1999-07-01

    By vacuum pyrolysis, the rubber portion of used tires is transformed into oil and gas and the carbon black filler is recovered as pyrolytic carbon black (CB{sub P}). Several commercial applications for the different products have been investigated and are reported in this article. CB{sub P} surface chemistry and activity are similar to those of commercial carbon blacks. Therefore, CB{sub P} has the potential to replace commercial carbon black grades in certain rubber applications. CB{sub P} was successfully tested as a filler in road pavement. The total pyrolytic oil can be used as a liquid fuel. The oil can also be distilled into different fractions: a light, a middle distillate and a heavy fraction. The light fraction was positively tested as a gasoline additive. Furthermore, this fraction contains valuable chemicals such as d,l-limonene. The middle fraction was successfully tested as a plasticizer in rubbers. The heavy fraction represents a good-quality feedstock for the production of coke and can also be used in road pavements. The pyrolytic gas can be used as a make-up heat source for the pyrolysis process

  10. Creep test under irradiation with thermal gradient for the cylindrical carbon fiber reinforced carbon composite. Interim report on irradiation examinations: 03M-47AS

    International Nuclear Information System (INIS)

    Baba, Shin-ichi; Sawa, Kazuhiro; Yamaji, Masatoshi; Matsui, Yoshinori; Ishihara, Masahiro

    2007-03-01

    The creep test under irradiation with thermal gradient for the cylindrical carbon fiber reinforced carbon composites (c/c composite) are carried out in the Japan Material Testing Reactor (JMTR). This report described 4-items; first item is design/evaluation of the capsule for the irradiation test, second is before irradiation measurements for the residual strain due to manufactured cylindrical c/c composite, and third is also before irradiation measurements of the distance between 2-holes of predrilled in the specimen and last item is examination of analysis for the irradiation creep with thermal gradient by VIENUS Code. The normal creep test is static mechanical load on the specimen in thermal condition, but this creep test under irradiation capsule is thermal stress due to thermal gradient at inside specimen in the thermal condition. Consequently, it is necessary as large as possible thermal gradient in the narrow space of the capsule inside volume. In which the tungsten rod (W-rod) was inserted to the cylindrical c/c composite specimen, for γ-ray heat generation density occurred highly and so maximize the difference temperatures of surface wall between inside and outside wall of the specimen. The measurement method of the deflection due to the irradiation creep of cylindrical c/c composite was adopted as way of ruptured the specimen among the predrilled distance of 2-holes before/after irradiation. Accordingly as the laser dimensional apparatus used to measure the distance between the 2-holes of specimen exactly, easy and untouchable. And also before irradiation measurement of the residual stress due to the manufactured process was estimated by neutron diffraction used Residual Stress Analyzer (RESA) at JRR-3M in JAEA. The irradiation test was finished as total irradiation time, average temperature and neutron dose showed 4189 hours, 873 K and 8.2x10 24 (E>1.0MeV:m -2 ) respectively. The thermal stress was estimated by the difference temperatures of 4

  11. The survival effects of V79 cells irradiated with carbon ions in different let

    International Nuclear Information System (INIS)

    Wang Jufang; Zhou Guangming; He Jing; Li Wenjian; Li Qiang; Dang Bingrong; Li Xinglin; Weng Xiaoqiong; Xie Hongmei; Wei Zengquan; Gao Qingxiang

    2001-01-01

    The survival of cultured Chinese V79 hamster cells irradiated with carbon ions with different LETs were investigated. Irradiation was performed at the heavy Ion Research Facility in Lanzhou (HIRFL). Results were compared with those obtained from the experiments with γ rats and could be concluded as follows: The survival curves for carbon ions showed as straight lines and were fitted to the one-target one-hit model, but for γ rays the curves with shoulders were fitted to the multi-target one-hit model. As the LETs were 125, 200 and 700 keV/μm for carbon ions, the inactivation cross section 35, 12 and 8 μm 2 , respectively, which suggested that under the experimental conditions, the lower the LET of carbon ions, the more seriously the irradiation killed cells. In the case of 125 keV/μm, the RBEs of carbon ions at the 0.1 and 0.37 survival levels were 1.47 and 2.19 respectively

  12. Electrochemical pre anodization of glassy carbon electrode and application to determine chloramphenicol

    International Nuclear Information System (INIS)

    Truc, Nguyen Minh; Mortensen, John; Anh, Nguyen Ba Hoai

    2008-01-01

    This paper suggested a method to enhance the performance of carbon electrodes for the determination of chloramphenicol (CAP). The sensitivity and the reproducibility of the carbon electrodes could be enhanced easily by electrochemical pretreatment. Some kinds of carbon material were studied including glassy carbon, graphite carbon and pyrolytic carbon. Numerous kinds of supporting electrolyte have been tried. For glassy carbon electrode, the acidic solution, H 2 SO 4 5 mM, resulted in best performance at pretreated voltage of +2.1V (vs. Ag/ AgCl) in duration of 250 second. However, for graphite and pyrolytic carbon electrodes, the phosphate buffer solution pH 6.0 gave the best performance at +1.7V (vs. Ag/ AgCl) in duration of 20 seconds. The detection limit could be at very low concentration of CAP: 0.8 ng/ ml for glassy carbon electrode, 3.5 ng/ ml for graphite carbon electrode. The method was successful applied to aqua-agriculture water sample and milk sample with simple extraction as well as direct ointment sample analysis. (author)

  13. Pyrolytic carbon microelectrodes for impedance based cell sensing

    DEFF Research Database (Denmark)

    Hassan, Yasmin Mohamed; Caviglia, Claudia; Hemanth, Suhith

    2016-01-01

    Electrically conductive glass-like carbon structures can be obtained from a polymer template through a pyrolysis process. These structures can be used as electrodes for bio sensing applications such as electrochemical evaluation of cell adhesion and proliferation. This study focuses on the optimi...... to decrease the resistivity of the resulting carbon material and improve the performance in cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Finally, EIS was used to monitor adhesion and proliferation of HeLa cells....

  14. Pyrolytic carbon black composite and method of making the same

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Paranthaman, Mariappan Parans; Bi, Zhonghe

    2016-09-13

    A method of recovering carbon black includes the step of providing a carbonaceous source material containing carbon black. The carbonaceous source material is contacted with a sulfonation bath to produce a sulfonated material. The sulfonated material is pyrolyzed to produce a carbon black containing product comprising a glassy carbon matrix phase having carbon black dispersed therein. A method of making a battery electrode is also disclosed.

  15. Feasibility of carbon-ion radiotherapy for re-irradiation of locoregionally recurrent, metastatic, or secondary lung tumors.

    Science.gov (United States)

    Hayashi, Kazuhiko; Yamamoto, Naoyoshi; Karube, Masataka; Nakajima, Mio; Tsuji, Hiroshi; Ogawa, Kazuhiko; Kamada, Tadashi

    2018-03-02

    Intrathoracic recurrence after carbon-ion radiotherapy for primary or metastatic lung tumors remains a major cause of cancer-related deaths. However, treatment options are limited. Herein, we report on the toxicity and efficacy of re-irradiation with carbon-ion radiotherapy for locoregionally recurrent, metastatic, or secondary lung tumors. Data of 95 patients with prior intrathoracic carbon-ion radiotherapy who were treated with re-irradiation with carbon-ion radiotherapy at our institution between 2006 and 2016 were retrospectively analyzed. Seventy-three patients (76.8%) had primary lung tumors and 22 patients (23.2%) had metastatic lung tumors. The median dose of initial carbon-ion radiotherapy was 52.8 Gy (relative biological effectiveness) and the median dose of re-irradiation was 66.0 Gy (relative biological effectiveness). None of the patients received concurrent chemotherapy. The median follow-up period after re-irradiation was 18 months. In terms of grade ≥3 toxicities, one patient experienced each of the following: grade 5 bronchopleural fistula, grade 4 radiation pneumonitis, grade 3 chest pain, and grade 3 radiation pneumonitis. The 2-year local control and overall survival rates were 54.0% and 61.9%, respectively. In conclusion, re-irradiation with carbon-ion radiotherapy was associated with relatively low toxicity and moderate efficacy. Re-irradiation with carbon-ion radiotherapy might be an effective treatment option for patients with locoregionally recurrent, metastatic, or secondary lung tumors. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  16. Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

    Science.gov (United States)

    Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

    2014-03-01

    Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

  17. Ellipsometric investigations of pyrolytically deposited thin indium oxide films

    International Nuclear Information System (INIS)

    Winkler, U.

    1980-01-01

    Ellipsometric measurements have been carried out of thin indium oxide films deposited pyrolytically on glass substrates. It was found that the roughness of the films affected the measuring results. Therefore, only after applying a two-layer model a reasonable interpretation of the measuring results became possible

  18. Ion-irradiation-induced defects in bundles of carbon nanotubes

    International Nuclear Information System (INIS)

    Salonen, E.; Krasheninnikov, A.V.; Nordlund, K.

    2002-01-01

    We study the structure and formation yields of atomic-scale defects produced by low-dose Ar ion irradiation in bundles of single-wall carbon nanotubes. For this, we employ empirical potential molecular dynamics and simulate ion impact events over an energy range of 100-1000 eV. We show that the most common defects produced at all energies are vacancies on nanotube walls, which at low temperatures are metastable but long-lived defects. We further calculate the spatial distribution of the defects, which proved to be highly non-uniform. We also show that ion irradiation gives rise to the formations of inter-tube covalent bonds mediated by carbon recoils and nanotube lattice distortions due to dangling bond saturation. The number of inter-tube links, as well as the overall damage, linearly grows with the energy of incident ions

  19. Pyrolytic Treatment and Fertility Enhancement of Soils Contaminated with Heavy Hydrocarbons.

    Science.gov (United States)

    Vidonish, Julia E; Zygourakis, Kyriacos; Masiello, Caroline A; Gao, Xiaodong; Mathieu, Jacques; Alvarez, Pedro J J

    2016-03-01

    Pyrolysis of contaminated soils at 420 °C converted recalcitrant heavy hydrocarbons into "char" (a carbonaceous material similar to petroleum coke) and enhanced soil fertility. Pyrolytic treatment reduced total petroleum hydrocarbons (TPH) to below regulatory standards (typically hydrocarbons (PAHs) was not observed, with post-pyrolysis levels well below applicable standards. Plant growth studies showed a higher biomass production of Arabidopsis thaliana and Lactuca sativa (Simpson black-seeded lettuce) (80-900% heavier) in pyrolyzed soils than in contaminated or incinerated soils. Elemental analysis showed that pyrolyzed soils contained more carbon than incinerated soils (1.4-3.2% versus 0.3-0.4%). The stark color differences between pyrolyzed and incinerated soils suggest that the carbonaceous material produced via pyrolysis was dispersed in the form of a layer coating the soil particles. Overall, these results suggest that soil pyrolysis could be a viable thermal treatment to quickly remediate soils impacted by weathered oil while improving soil fertility, potentially enhancing revegetation.

  20. Experimental investigation of linear thermal expansion of pyrolytic graphite at high temperatures

    Science.gov (United States)

    Senchenko, V. N.; Belikov, R. S.

    2017-11-01

    Using the previously described [1] experimental setup for investigation of the thermophysical properties of refractory materials under high pressure and temperature a few experiments with pyrolytic graphite were carried out. The density of the material was equal to 2.18 g/cm3. Experimental data on the linear thermal expansion in the perpendicular and parallel to the basal plane direction were obtained. Thermal expansion in the perpendicular to the basal plane direction during the heating from room temperature up to the melting point was 16.4 ± 1.6%. The results obtained allow calculating the density of pyrolytic graphite in the wide range of high temperatures up to the melting point.

  1. Effect of thermal annealing on property changes of neutron-irradiated non-graphitized carbon materials and nuclear graphite

    International Nuclear Information System (INIS)

    Matsuo, Hideto

    1991-06-01

    Changes in dimension of non-graphitized carbon materials and nuclear graphite, and the bulk density, electrical resistivity, Young's modulus and thermal expansivity of nuclear graphite were studied after neutron irradiation at 1128-1483 K and the successive thermal annealing up to 2573 K. Carbon materials showed larger and anisotropic dimensional shrinkage than that of nuclear graphite after the irradiation. The irradiation-induced dimensional shrinkage of carbon materials decreased during annealing at temperatures from 1773 to 2023 K, followed by a slight increase at higher temperatures. On the other hand, the irradiated nuclear graphite hardly showed the changes in length, density and thermal expansivity under the thermal annealing, but the electrical resistivity and Young's modulus showed a gradual decrease with annealing temperature. It has been clarified that there exists significant difference in the effect of thermal annealing on irradiation-induced dimensional shrinkage between graphitized nuclear graphite and non-graphitized carbon materials. (author)

  2. The irradiation studies on diamond-like carbon films

    CERN Document Server

    LiuGuIang; Xie Er Qin

    2002-01-01

    Diamond-like carbon (DLC) films have been deposited on glass substrates using radio-frequency (r.f.) plasma deposition method. gamma-ray, ultraviolet (UV) ray and neutron beam were used to irradiate the DLC films. Raman spectroscopy and infrared (IR) spectroscopy were used to characterize the changing characteristics of SP sup 3 C-H bond and hydrogen content in the films due to the irradiations. It showed that, the damage degrees of the gamma-ray, UV ray and neutron beam on the SP sup 3 C-H bonds are different. Among them, the damage of gamma-ray on the SP sup 3 C-H bond is the weakest. When the irradiation dose of gamma-ray reaches 10x10 sup 4 Gy, the SP sup 3 C-H bond reduces about 50% in number. The square resistance of the films is reduced due to the irradiation of UV ray and this is caused by severe oxidation of the films. Compared with that of the as-deposited one, the IR transmittance of the films irradiated by both gamma-ray and neutron beam is increased to some extent. By using the results on optical...

  3. Overliming detoxification of pyrolytic sugar syrup for direct fermentation of levoglucosan to ethanol.

    Science.gov (United States)

    Chi, Zhanyou; Rover, Marjorie; Jun, Erin; Deaton, Mark; Johnston, Patrick; Brown, Robert C; Wen, Zhiyou; Jarboe, Laura R

    2013-12-01

    The application of pyrolytic sugars for biofuel production through fermentation is challenged by inhibitory contaminant compounds. Inhibition is so severe that only 0.25% sugar syrup can be used. In this study, overliming was tested as a simple detoxification method, using the Escherichia coli KO11+ lgk to directly convert levoglucosan into ethanol. After treatment with at least 14.8 g/L of Ca(OH)2, fermentation with 2% (w/v) pyrolytic sugar syrup was observed with no inhibition of ethanol production. Further investigation of treatment time and temperature showed that 8-16 h of treatment at 20°C, and 1-4 h of treatment at 60°C are necessary to obtain consistent ethanol production. The samples treated with 18.5 g/L Ca(OH)2 at 60°C for 4 h showed no inhibition at 2.5%. Multiple contaminants removed by the overliming treatment were identified. This study demonstrates that overliming is a promising method for detoxification of pyrolytic sugars for fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Investigation on the rapid degradation of congo red catalyzed by activated carbon powder under microwave irradiation

    International Nuclear Information System (INIS)

    Zhang Zhaohong; Shan Yabo; Wang Jun; Ling Hongjie; Zang Shuliang; Gao Wei; Zhao Zhe; Zhang Huachun

    2007-01-01

    Azo dyestuff-congo red in aqueous solution can be degraded rapidly under microwave irradiation in the presence of activated carbon powder. The results showed that the degradation ratio could reach 87.79% for 25 mL total volume with 50 mg/L congo red and 2.0 g/L activated carbon powder under 1.5 min microwave irradiation. Furthermore, within the same irradiation time, congo red could be degraded fully by increasing addition amount (e.g. 3.6 g/L) of activated carbon powder and the degradation ratio was up to 96.49%. Otherwise, with the same addition amount, congo red also could be degraded completely by prolonging irradiation time (e.g. 2.5 min) and the degradation ratio was up to 97.88%. In addition, the influences of microwave irradiation time, initial concentration of congo red, addition amount and used times of activated carbon powder as well as solution acidity on the degradation were discussed in details adopting UV-vis spectra, FT-IR spectra, ion chromatography, high phase liquid chromatography (HPLC) and TOC analysis technologies. Here, the method using activated carbon powder as catalyst under microwave irradiation shows many advantages including high degradation ratios, short reaction time, low costs, no intermediates and no secondary pollution. Therefore, it may be fit for dealing with various azo dyestuff wastewaters on a large scale

  5. In vitro co-culture experiments on prostate cancer and small intestine cells irradiated with carbon ions and x-rays

    International Nuclear Information System (INIS)

    Neubeck, C. von; Weyrather, W.-K.; Durante, M.

    2009-01-01

    Intensity modulated radiotherapy (IMRT) delivers the dose in many small irradiation fields of different beam direction to achieve a 3 dimensional tumour conformal dose overlapping with a maximum of normal tissue protection. In 2006 a study was started at GSI to treat prostate cancer patients with a boost irradiation of carbon ions in combination with an IMRT treatment administered at the Uniklinikum Heidelberg. The carbon ions are delivered in two opposing fields. So IMRT irradiation includes more normal tissue than carbon ion treatment but even here parts of the rectum and the bladder are in the irradiated field. This raises the question whether the irradiated tumor cells influence the normal cells (irradiated/ unirradiated) but also whether the normal irradiated cells influences normal tissue in a different way for carbon and photon irradiation. To study this problem, we established an in vitro co-culture model of prostate cancer and small intestine cells of the rat to simulate the patient treatment situation for analyzing tissue reaction exemplary. For characterization of the cells lines the parameters alpha and beta (linear quadratic model) for clonogenic survival were determined for x-rays and for carbon ions of different energies. For co-culture experiments unirradiated and irradiated cells were seeded together and the survival was analyzed

  6. Effect of ultraviolet light irradiation on amorphous carbon nitride films

    International Nuclear Information System (INIS)

    Zhang, M.; Nakayama, Y.

    1997-01-01

    The amorphous carbon nitride films were produced using electron cyclotron resonance nitrogen plasma with various mixtures of N 2 and CH 4 gases. The dependence of film structures on the nitrogen incorporation and the structural modifications of the film due to ultraviolet (UV) light irradiation were investigated using infrared and UV-VIS spectroscopy. It is found that UV irradiation results in the decrease of CH bonding, increase of CC and CN double bonding in the film and increase of the optical band gap of the film. It appears that both bond removal and reordering have taken place as a result of UV irradiation. The structural modifications due to nitrogen incorporation and UV light irradiation are explained by a cluster model. copyright 1997 American Institute of Physics

  7. The resistance changes of carbon and metal oxide film resistors by irradiation of 60Co γ rays

    International Nuclear Information System (INIS)

    Okamoto, Shinichi; Fujino, Takahiro; Furuta, Junichiro; Yoshida, Toshio

    1979-01-01

    The resistance changes of glass-sealed deposited-carbon-film and carbon-coated-film resitors and metal oxide glazed resistors made in USA were studied by gamma-ray irradiation. (1) The resistances of deposited-carbon-film resistors of 50, 100 and 200 megohm did not change by irradiation of gamma rays up to 1.9 x 10 9 R. (2) The carbon-coated-film resistors of 100, 1000, 10000 and 100000 megohm had negative resistance changes by irradiation of gamma rays up to 9.9 x 10 8 R. (3) The resistances of metal oxide glazed resistors of 100, 1000 and 10000 megohm did not change by irradiation of gamma rays up to 8.8 x 10 8 R. When radiation monitoring instruments with hi-meg resistors are used in a gamma field with high intensity, the resistors must not be exposed to gamma rays with high doses, or the resistors which do not change by gamma-ray irradiation must be selected. (author)

  8. Improvement of Electrical Conductivity of Single-Walled Carbon Nano tube Network Using Particle Irradiation

    International Nuclear Information System (INIS)

    Lim, Suntaek; Kim, Gonho

    2010-01-01

    Substitution for Indium Tin Oxide of transparent electrode Applications : Flat panel displays, Touch panel, Solar cell, EM wave shielding... For very low energy of 20 eV and 90 eV, argon ion irradiations, the surface of SWCNT bundles were sputtered and thinned the diameter of the bundle. With increasing the incident ion energy as 7.5 keV, SWCNT bundles were networked by amorphization of cross welded CNTs. → Less damage can be obtained from higher energy of irradiated particle due to less collision cross section. For 10 MeV proton and 800 keV electron irradiations, there are no severe damages. Electron irradiation is more effective on network with less damage than that of ion irradiation. → Network process can be proceeded with the generation of free carbon, the migration of free carbon on CNT and reconstruction of the cross linked CNTs, which processes require the latent energy on CNT body after collision. It can be controlled by the energy and dose of irradiation particle

  9. Carbon protrusions on PTFE surface prepared by ion irradiation and chemical defluorination

    Science.gov (United States)

    Kobayashi, T.; Iwaki, M.

    2006-01-01

    A surface of PTFE was covered with small protrusions by ion-beam irradiation. In this study, we converted PTFE protrusions into carbon protrusions by a defluorination (carbonization) process using sodium vapor. The morphology, composition and structure were analyzed by SEM-EDX, Raman spectroscopy and TEM. The irradiated PTFE sheets were packed in evacuated glass tubes with a sodium block and kept at 473 K for 2-48 h. The samples were then rinsed in HCl and distilled water to remove NaF precipitates. The EDX measurement showed that the NaF precipitates were completely removed by washing, and the percentage of carbon atoms was controlled from 60% to 99% by the treatment. Raman spectra showed that graphite structures grow during the defluorination process. TEM micrographs showed that the protrusions have a bubble structure and are covered with a thin wall. The carbonized protrusions were conductive and grew perpendicular to the substrate.

  10. Nitrogen-Rich Polyacrylonitrile-Based Graphitic Carbons for Hydrogen Peroxide Sensing

    Directory of Open Access Journals (Sweden)

    Brandon Pollack

    2017-10-01

    Full Text Available Catalytic substrate, which is devoid of expensive noble metals and enzymes for hydrogen peroxide (H2O2, reduction reactions can be obtained via nitrogen doping of graphite. Here, we report a facile fabrication method for obtaining such nitrogen doped graphitized carbon using polyacrylonitrile (PAN mats and its use in H2O2 sensing. A high degree of graphitization was obtained with a mechanical treatment of the PAN fibers embedded with carbon nanotubes (CNT prior to the pyrolysis step. The electrochemical testing showed a limit of detection (LOD 0.609 µM and sensitivity of 2.54 µA cm−2 mM−1. The promising sensing performance of the developed carbon electrodes can be attributed to the presence of high content of pyridinic and graphitic nitrogens in the pyrolytic carbons, as confirmed by X-ray photoelectron spectroscopy. The reported results suggest that, despite their simple fabrication, the hydrogen peroxide sensors developed from pyrolytic carbon nanofibers are comparable with their sophisticated nitrogen-doped graphene counterparts.

  11. Effects of ion beam irradiation on the microstructures and strengths of different carbon fibers

    International Nuclear Information System (INIS)

    Oku, Tatsuo; Kurumada, Akira; Kawamata, Kiyohiro; Inagaki, Michio

    1998-01-01

    The high energy argon ion was irradiated to different carbon fibers with various microstructures. The cross-sectional structures and strengths properties have been evaluated before and after ion irradiation. As a result, the diameter of fibers decreased due to ion irradiation, except for the fiber with dual structure. The tensile strength also decreased due to ion irradiation, except for fibers which were not heat-treated. This suggests that it is necessary to consider not only the defects in the vertical cross-section but also changes in defect structures in the axial direction. The results of computer simulation indicated that argon ion with 175MeV/1μA produced homogeneous defects in the carbon fibers with the diameter of about 20 μm. (author)

  12. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    Science.gov (United States)

    Ziegler, Kirk J. (Inventor); Rauwald, Urs (Inventor); Hauge, Robert H. (Inventor); Schmidt, Howard K. (Inventor); Smalley, Richard E. (Inventor); Kittrell, W. Carter (Inventor); Gu, Zhenning (Inventor)

    2013-01-01

    According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.

  13. Methods for the characterization of pyrolytic deposited carbon

    International Nuclear Information System (INIS)

    Bongartz, K.; Hoven, H.; Koizlik, K.

    Pyrocarbon is deposited as a coating material on fuel kernels used in HTGRs. For the development of particle coatings specified for various reactor designs, it is necessary to know the properties of pyrocarbon and their changes by neutron irradiation. In this report, procedures are described which are used to characterize pyrocarbon: measurement of geometry, density, microporosity, apparent crystallite size, anisotropy of orientation, modulus of elasticity, and strength of coatings, as well as ceramography, etching by oxidation, secondary and transmission electron microscopy. (auth)

  14. Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; Scott Ploger; John Hunn

    2012-05-01

    The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Five irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These five compacts also included all four TRISO coating variations irradiated in the AGR experiment. The five compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. Approximately 40 to 80 particles within each cross section were exposed near enough to mid-plane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 830 classified particles allowed other relationships among morphological types to be established.

  15. Ceramographic Examinations of Irradiated AGR-1 Fuel Compacts

    International Nuclear Information System (INIS)

    Demkowicz, Paul; Ploger, Scott; Hunn, John

    2012-01-01

    The AGR 1 experiment involved irradiating 72 cylindrical fuel compacts containing tri-structural isotropic (TRISO)-coated particles to a peak burnup of 19.5% fissions per initial metal atom with no in-pile failures observed out of almost 300,000 particles. Five irradiated AGR 1 fuel compacts were selected for microscopy that span a range of irradiation conditions (temperature, burnup, and fast fluence). These five compacts also included all four TRISO coating variations irradiated in the AGR experiment. The five compacts were cross-sectioned both transversely and longitudinally, mounted, ground, and polished after development of careful techniques for preserving particle structures against preparation damage. Approximately 40 to 80 particles within each cross section were exposed near enough to mid-plane for optical microscopy of kernel, buffer, and coating behavior. The microstructural analysis focused on kernel swelling and porosity, buffer densification and fracture, debonding between the buffer and inner pyrolytic carbon (IPyC) layers, and fractures in the IPyC and SiC layers. Three basic particle morphologies were established according to the extent of bonding between the buffer and IPyC layers: complete debonding along the interface (Type A), no debonding along the interface (Type B), and partial debonding (Type AB). These basic morphologies were subdivided according to whether the buffer stayed intact or fractured. The resulting six characteristic morphologies were used to classify particles within each cross section, but no spatial patterns were clearly observed in any of the cross-sectional morphology maps. Although positions of particle types appeared random within compacts, examining a total of 830 classified particles allowed other relationships among morphological types to be established.

  16. Changes in the thermoelectric response of vitreous carbon due to the irradiation by γ-rays

    Science.gov (United States)

    Culebras, M.; Madroñero, A.; Mota, C.; Gómez, C. M.; Amo, Jose M.; Cantarero, A.

    2014-07-01

    In order to study variations in the thermoelectric properties, some commercial glassy carbon samples were subjected to a sequence of steps consisting of a combination of irradiation with γ-rays produced by radioisotopes 60Co, and hydrogen adsorption when the samples were put in an over pressured atmosphere of this gas. With this procedure it was possible to observe that the irradiation decreases the electrical conductivity of glassy carbon samples and the hydrogenation changes the sign of Seebeck coefficient. The material initially is an n-type semiconductor, but with hydrogenation changes to p-type semiconductor. X-ray diffraction analysis showed that the hydrogenated vitreous carbon is more amorphous than the pristine material and the γ-rays irradiation produces changes in the crystallite size and shape.

  17. Using pyrolytic acid leaching as a pretreatment step in a biomass fast pyrolysis plant: process design and economic evaluation

    NARCIS (Netherlands)

    Oudenhoven, Stijn; van der Ham, Aloysius G.J.; van den Berg, Henderikus; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.

    2016-01-01

    Removing alkali and alkaline earth metals (AAEMs) from biomass, with pyrolytic acids, before pyrolysis leads to increased organic oil and sugar yields. These pyrolytic acids are produced and concentrated within the pyrolysis process itself. The purpose of this paper was to evaluate under which

  18. Influence of pyrolytic temperature on uranium adsorption capability by biochar derived from macauba coconut residue

    Energy Technology Data Exchange (ETDEWEB)

    Guilhen, Sabine Neusatz; Fungaro, Denise Alves [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Coleti, Jorge; Tenório, Jorge Alberto Soares, E-mail: snguilhen@ipen.br, E-mail: dfungaro@ipen.br, E-mail: jorgecoleti@usp.br, E-mail: jtenorio@usp.br [Universidade de São Paulo (USP), São Paulo, SP (Brazil). Departamento de Engenharia Metalúrgica e de Materiais

    2017-07-01

    Biochar (BC) is a carbon-rich product obtained when biomass is thermally decomposed at relatively low temperatures (under 700°C) and limited supply of oxygen in a process called pyrolysis. The conversion of biomass into BC can not only result in renewable energy source of synthetic gas and bio-oil, but also decrease the content of CO{sub 2} in the atmosphere, as well as improving soil fertility. Because of its porous structure, charged surface and surface functional groups, BC exhibits a great potential as an adsorbent. Brazilian agro energy chain involves tons of biomass waste, providing a wide range of biomass with different chemical and physical properties. BC characteristics strongly depend on the feedstock and the pyrolysis conditions, in which the temperature is the key parameter. The aim of this study was to evaluate the adsorption potential for the removal of uranium, U(VI), from aqueous solutions using BC obtained through the pyrolysis of the Macauba (Acrocomia aculeata) coconut endocarp as a function of the final pyrolytic temperature. BCs produced at higher temperatures are likely to present lower H/C and O/C ratios, indicating the loss of easily degradable carbon compounds such as volatile matter. In contrast, low-temperature pyrolysis produces not only a higher BC yield, but also richer in surface functional groups which will likely enable interactions with the U(VI) ions. The endocarp was subjected to six different pyrolytic temperatures, ranging from 250°C to 750 °C. The influence of parameters such as pH, sorbent dose and initial concentration on the adsorption of U(VI) was investigated. The maximum adsorption capacity (q) was achieved for the BC obtained at 250°C (BC250), which presented a removal percentage of approx. 86%, demonstrating the potential of the BC from macauba endocarp for treatment of wastewaters. Thus, submitting the endocarp to temperatures higher than 250°C becomes unnecessary, saving time and reducing operating costs

  19. Influence of pyrolytic temperature on uranium adsorption capability by biochar derived from macauba coconut residue

    International Nuclear Information System (INIS)

    Guilhen, Sabine Neusatz; Fungaro, Denise Alves; Coleti, Jorge; Tenório, Jorge Alberto Soares

    2017-01-01

    Biochar (BC) is a carbon-rich product obtained when biomass is thermally decomposed at relatively low temperatures (under 700°C) and limited supply of oxygen in a process called pyrolysis. The conversion of biomass into BC can not only result in renewable energy source of synthetic gas and bio-oil, but also decrease the content of CO 2 in the atmosphere, as well as improving soil fertility. Because of its porous structure, charged surface and surface functional groups, BC exhibits a great potential as an adsorbent. Brazilian agro energy chain involves tons of biomass waste, providing a wide range of biomass with different chemical and physical properties. BC characteristics strongly depend on the feedstock and the pyrolysis conditions, in which the temperature is the key parameter. The aim of this study was to evaluate the adsorption potential for the removal of uranium, U(VI), from aqueous solutions using BC obtained through the pyrolysis of the Macauba (Acrocomia aculeata) coconut endocarp as a function of the final pyrolytic temperature. BCs produced at higher temperatures are likely to present lower H/C and O/C ratios, indicating the loss of easily degradable carbon compounds such as volatile matter. In contrast, low-temperature pyrolysis produces not only a higher BC yield, but also richer in surface functional groups which will likely enable interactions with the U(VI) ions. The endocarp was subjected to six different pyrolytic temperatures, ranging from 250°C to 750 °C. The influence of parameters such as pH, sorbent dose and initial concentration on the adsorption of U(VI) was investigated. The maximum adsorption capacity (q) was achieved for the BC obtained at 250°C (BC250), which presented a removal percentage of approx. 86%, demonstrating the potential of the BC from macauba endocarp for treatment of wastewaters. Thus, submitting the endocarp to temperatures higher than 250°C becomes unnecessary, saving time and reducing operating costs. (author)

  20. Multiferroic BiFeO3 thin films and nanodots grown on highly oriented pyrolytic graphite substrates

    Science.gov (United States)

    Shin, Hyun Wook; Son, Jong Yeog

    2017-12-01

    Multiferroic BiFeO3 (BFO) thin films and nanodots are deposited on highly oriented pyrolytic graphite (HOPG) substrates via a pulsed laser deposition technique, where the HOPG surface has a honeycomb lattice structure made of carbon atoms, similar to graphene. A graphene/BFO/HOPG capacitor exhibited multiferroic properties, namely ferroelectricity (a residual polarization of 26.8 μC/cm2) and ferromagnetism (a residual magnetization of 1.1 × 10-5 emu). The BFO thin film had high domain wall energies and demonstrated switching time of approximately 82 ns. An 8-nm BFO nanodot showed a typical piezoelectric hysteresis loop with an effective residual piezoelectric constant of approximately 110 pm/V and exhibited two clearly separated current curves depending on the ferroelectric polarization direction.

  1. Effect of ion irradiation on the structure and the surface topography of carbon fiber

    International Nuclear Information System (INIS)

    Ligacheva, E.A.; Galyaeva, L.V.; Gavrilov, N.V.; Belykh, T.A.; Ligachev, A.E.; Sokhoreva, V.V.

    2006-01-01

    The effect of C + ion irradiation (40 keV, 10 15 - 10 19 cm -2 ) on the structure and surface topography of high-module carbon fibers is investigated. Interplanar distance and internal stress values are found to be minimal at a radiation dose of 10 17 cm -2 , the height of a layer pack being practically unchanged. The relief of ion irradiated carbon fiber surface constitutes regularly repetitive valleys and ridges spaced parallel with the fiber axis [ru

  2. Enhancement of adhesion between carbon nanotubes and polymer substrates using microwave irradiation

    International Nuclear Information System (INIS)

    Shim, Hyung Cheoul; Kwak, Yoon Keun; Han, Chang-Soo; Kim, Soohyun

    2009-01-01

    This paper reports the enhancement of adhesive strength between single-walled carbon nanotubes (SWNTs) and polymer substrates using microwave irradiation of 0-5 min duration at 2.45 GHz and 800 W. Field emission scanning electron microscopy images, ultraviolet-visible data and four-point probe sheet resistance measurement data indicate that microwave irradiation is effective for enhancement of adhesion between SWNTs and polymer substrates. SWNTs could be locally welded onto a polymer substrate due to their active response to microwave irradiation.

  3. London forces in highly oriented pyrolytic graphite

    Directory of Open Access Journals (Sweden)

    L.V. Poperenko

    2017-07-01

    Full Text Available Surface of highly oriented pyrolytic graphite with terrace steps was studied using scanning tunneling microscopy with high spatial resolution. Spots with positive and negative charges were found in the vicinity of the steps. Values of the charges depended both on the microscope needle scan velocity and on its motion direction. The observed effect was theoretically explained with account of London forces that arise between the needle tip and the graphite surface. In this scheme, a terrace step works as a nanoscale diode for surface electric currents.

  4. Thermal studies on unirradiated and γ-irradiated polymer of allyl diglycol carbonate

    International Nuclear Information System (INIS)

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

    1995-01-01

    The thermal decomposition of unirradiated and γ-irradiated (5.93-15.5 MRad dose range) allyl diglycol carbonate polymer (trade name, CR-39) was studied by thermogravimetry (TG) and differential thermal analysis (DTA). These studies indicate four main decomposition steps in CR-39 polymer in air. Assessment of the influence of radiation dose on the above range shows that while the 5.93 MRad γ-irradiated polymer CR-39 degrades in three steps, the 15.5 MRad γ-irradiated polymer degrades in only two steps. The kinetics of the different stages of degradation were also evaluated from the TG curves. Irradiation enhances the decomposition rate and the effect increases further with increasing radiation dose. The activation energy values calculated for all the decomposition stages decrease on irradiation

  5. Molecular Ultrasound Imaging of Early Vascular Response in Prostate Tumors Irradiated with Carbon Ions

    Directory of Open Access Journals (Sweden)

    Moritz Palmowski

    2009-09-01

    Full Text Available Individualized treatments with combination of radiotherapy and targeted drugs require knowledge about the behavior of molecular targets after irradiation. Angiogenic marker expression has been studied after conventional radiotherapy, but little is known about marker response to charged particles. For the very first time, we used molecular ultrasound imaging to intraindividually track changes in angiogenic marker expression after carbon ion irradiation in experimental tumors. Expression of intercellular adhesion molecule-1 (ICAM-1 and of αvβ3-integrin in subcutaneous AT-1 prostate cancers in rats treated with carbon ions (16 Gy was studied using molecular ultrasound and immunohistochemistry. For this purpose, cyanoacrylate microbubbles were synthesized and linked to specific ligands. The accumulation of targeted microbubbles in tumors was quantified before and 36 hours after irradiation. In addition, tumor vascularization was analyzed using volumetric Doppler ultrasound. In tumors, the accumulation of targeted microbubbles was significantly higher than in nonspecific ones and could be inhibited competitively. Before irradiation, no difference in binding of αvβ3-integrin-specific or ICAM-1-specific microbubbles was observed in treated and untreated animals. After irradiation, however, treated animals showed a significantly higher binding of αvβ3-integrin-specific microbubbles and an enhanced binding of ICAM-1-specific microbubbles than untreated controls. In both groups, a decrease in vascularization occurred during tumor growth, but no significant difference was observed between irradiated and nonirradiated tumors. In conclusion, carbon ion irradiation upregulates ICAM-1 and αvβ3-integrin expression in tumor neovasculature. Molecular ultrasound can indicate the regulation of these markers and thus may help to identify the optimal drugs and time points in individualized therapy regimens.

  6. Carbon/H-ZSM-5 composites as supports for bi-functional Fischer-Tropsch synthesis catalysts

    NARCIS (Netherlands)

    Valero-Romero, M.J.; Sartipi, S.; Sun, X.; Rodríguez-Mirasol, J.; Cordero, T.; Kapteijn, F.; Gascon, J.

    2016-01-01

    Mesoporous H-ZSM-5–carbon composites, prepared via tetrapropylammonium hydroxide (TPAOH) post treatment of H-ZSM-5 followed by deposition of pyrolytic carbon, have been used as the support for the preparation of Co-based Fischer–Tropsch catalysts. The resulting catalysts display an improved

  7. Preparation and electrical-property characterization of poly(vinyl chloride)-derived carbon nanosheet by ion beam irradiation-induced carbon clustering and carbonization

    Science.gov (United States)

    Jung, Chan-Hee; Sohn, Joon-Yong; Kim, Hyo-Sub; Hwang, In-Tae; Lee, Hong-Joon; Shin, Junhwa; Choi, Jae-Hak

    2018-05-01

    In this work, we demonstrated that carbon nanosheet (CNS) can easily be produced by a room-temperature, solid-state proton irradiation-induced clustering of poly(vinyl chloride) (PVC) films followed by carbonization. The results of the optical, chemical, and structural analyses revealed that oxidized and sp2-hybridized carbon clusters were effectively created in the PVC thin film by combined dehydrochlorination and inter-coupling reactions during proton irradiation. This was further converted to pseudo-hexagonally-structured nano-crystalline CNS with 2-D symmetry and metallic transporting character by high-temperature treatment. As a result, the CNS exhibited a very high electrical conductivity (587 S/cm) without a significant change in their thickness, a low surface roughness (0.36 nm), and a high work function (5.11 eV). These findings demonstrate that the radiation-based approach opens new avenues for the design and development of 2-D CNS as a graphene allotrope for the application of electronic devices, including field-effect transistors, electric heating devices, biosensors, supercapacitors, and fuel cells.

  8. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

  9. Huge magnetoresistance effect of highly oriented pyrolytic graphite

    International Nuclear Information System (INIS)

    Du Youwei; Wang Zhiming; Ni Gang; Xing Dingyu; Xu Qingyu

    2004-01-01

    Graphite is a quasi-two-dimensional semimetal. However, for usual graphite the magnetoresistance is not so high due to its small crystal size and no preferred orientation. Huge positive magnetoresistance up to 85300% at 4.2 K and 4950% at 300 K under 8.15 T magnetic field was found in highly oriented pyrolytic graphite. The mechanism of huge positive magnetoresistance is not only due to ordinary magnetoresistance but also due to magnetic-field-driven semimetal-insulator transition

  10. Transplantation of ES cells to Parkinson model rat irradiated with carbon ion beam

    International Nuclear Information System (INIS)

    Inaji, Motoki; Okauchi, Takashi; Nagai, Yuji; Nojima, Kumie; Suhara, Tetsuya

    2004-01-01

    The present study was designed to make a new Parkinson disease model using carbon ion beam. In this year, we irradiated right middle forebrain bundle of adult rats with charged carbon particles (290 MeV/nucleon, Mono peak, 150 Gy) and damaged right dopaminergic neurons pathway. To irradiate precisely, rats were set in the stereotactic frame with ear bars which was developed in this year. In 4 weeks after the irradiation, we performed methamphetamine induced rotation test and the autoradiography measurement on dopamine transporter using [ 11 C]PE2I to assess degeneration of dopaminergic neurons in caudate putamen (Cpu). As a result, ipsilateral rotation was observed and the distributions of dopamine transporter in the striatum decreased significantly. These results are similar to those of 6-OHDA lesioned rats, and indicate validity of this model. (author)

  11. A study of point defects created by electron irradiation of dilute iron-carbon alloys; Etude des defauts crees par irradiation electronique dans les alliages de fer carbone dilues

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, J L [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-10-01

    Resistivity and magnetic after effect (m.a.e.) measurements are used to study the influence of carbon atoms on the annealing process of point defects created by electron irradiation (3 MeV) at low temperature (20 deg. K). The presence of the carbon atoms has a strong influence on the recovery sub-stage I{sub E} and stage III. For the former, the carbon impurity traps the freely migrating iron interstitial. For the latter the effect is interpreted as being due to formation during annealing, of a carbon vacancy pair. A pronounced m.a.e. band is attributed to the reorientation of this carbon vacancy complex. All these results are coherent with the interpretation of a low temperature migrating free interstitial. (author) [French] L'influence des atomes de carbone sur le recuit des defauts ponctuels crees par irradiation electronique (3 MeV) a basse temperature (20 deg. K) dans le fer est mise en evidence par des mesures de resistivite electrique, et de trainage magnetique. Cette influence se manifeste principalement au cours du sous stade I{sub E} et du stade III de resistivite. Au sous stade I{sub E} les atomes de carbone piegeraient les interstitiels libres de fer au cours de leur migration. Le stade III est interprete comme etant du a la recombinaison du carbone dans les lacunes. Une importante bande de tramage magnetique etant attribuee a la reorientation de ce complexe. Ces resultats sont coherents avec l'interpretation faisant migrer a basse temperature l'interstitiel libre. (auteur)

  12. Mutagenic effects of carbon ion beam irradiations on dry Lotus japonicus seeds

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shanwei [Biophysics Group, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, Libin, E-mail: libinzhou@impcas.ac.cn [Biophysics Group, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); Li, Wenjian; Du, Yan [Biophysics Group, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); Yu, Lixia; Feng, Hui; Mu, Jinhu [Biophysics Group, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Yuze [College of Life Science and Technology, Gansu Agricultural University, No. 1 Yingmen Village, Anning District, Lanzhou, Gansu Province 730070 (China)

    2016-09-15

    Carbon ion beam irradiation is a powerful method for creating mutants and has been used in crop breeding more and more. To investigate the effects of carbon ion beams on Lotus japonicus, dry seeds were irradiated by 80 MeV/u carbon ion beam at dosages of 0, 100, 200, 300, 400, 500 and 600 Gy. The germination rate, survival rate and root length of M{sub 1} populations were explored and the dose of 400 Gy was selected as the median lethal dose (LD{sub 50}) for a large-scale mutant screening. Among 2472 M{sub 2} plants, 127 morphological mutants including leaf, stem, flower and fruit phenotypic variation were found, and the mutation frequency was approximately 5.14%. Inter simple sequence repeat (ISSR) assays were utilized to investigate the DNA polymorphism between seven mutants and eight plants without phenotypic variation from M{sub 2} populations. No remarkable differences were detected between these two groups, and the total polymorphic rate was 0.567%.

  13. Tissue irradiator

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-01-01

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in-vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood-carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170

  14. Influence of ultraviolet light irradiation on the corrosion behavior of carbon steel AISI 1015

    Science.gov (United States)

    Riazi, H. R.; Danaee, I.; Peykari, M.

    2013-03-01

    Corrosion of carbon steel in sodium chloride solution was studied under ultraviolet illumination using weight loss, polarization, electrochemical impedance spectroscopy and current transient tests. The polarization test revealed an increase in the corrosion current density observed under UV illumination. The impedance spectroscopy indicated that the charge transfer resistance of the system was decreased by irradiation of UV light on a carbon steel electrode. The weight loss of carbon steel in solution increased under UV light, which confirms the results obtained from electrochemical measurements. We propose that the main effect of UV irradiation is on the oxide film, which forms on the surface. Thus, in presence of UV, the conductivity of oxide film might increase and lead to higher metal dissolution and corrosion rate.

  15. Sustainable pyrolytic sludge-char preparation on improvement of closed-loop sewage sludge treatment: Characterization and combined in-situ application.

    Science.gov (United States)

    Jin, Zhengyu; Chang, Fengmin; Meng, Fanlin; Wang, Cuiping; Meng, Yao; Liu, Xiaoji; Wu, Jing; Zuo, Jiane; Wang, Kaijun

    2017-10-01

    Aiming at closed-loop sustainable sewage sludge treatment, an optimal and economical pyrolytic temperature was found at 400-450 °C considering its pyrolysis efficiency of 65%, fast cracking of hydrocarbons, proteins and lipids and development of aromatized porous structure. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) tests demonstrated the development of adsorptive functional groups and crystallographic phases of adsorptive minerals. The optimal sludge-char, with a medium specific surface area of 39.6 m 2  g -1 and an iodine number of 327 mgI 2 g -1 , performed low heavy metals lixiviation. The application of sludge-char in raw sewage could remove 30% of soluble chemical oxygen demand (SCOD), along with an acetic acid adsorption capacity of 18.0 mg g -1 . The developed mesopore and/or macropore structures, containing rich acidic and basic functional groups, led to good biofilm matrices for enhanced microbial activities and improved autotrophic nitrification in anoxic stage of an A/O reactor through adsorbed extra carbon source, and hence achieved the total nitrogen (TN) removal up to 50.3%. It is demonstrated that the closed-loop sewage sludge treatment that incorporates pyrolytic sludge-char into in-situ biological sewage treatment can be a promising sustainable strategy by further optimization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Optical and electrical phenomena in dielectric materials under irradiation

    CERN Document Server

    Plaksin, O A; Stepanov, P A; Demenkov, P V; Chernov, V M; Krutskikh, A O

    2002-01-01

    Optical and acoustic properties of the materials based on Al sub 2 O sub 3 , SiO sub 2 and BN under 8 MeV proton irradiation (<10 sup 4 Gy/s) have been measured. Electric charge partitioning has been shown to result in charging the microscopic regions in the bulk of the dielectrics under irradiation, which is due to different mobility of free electrons and holes (sapphire), concentration inhomogeneity in the system of charge carrier traps (alumina), or thermodynamic instability of the homogeneous distribution of the filled traps (silica glasses). Prevalent charge carrier recombination in the grain boundaries causes re-crystallization of pyrolytic boron nitride under irradiation, which shows up as simultaneous decrease of the intensity of radiation-induced luminescence (RIL) of the centres in the grain boundaries and the BN. The local charging results in optical inhomogeneity of the silica glasses which is sustained by the optical loss spectra of the irradiated glasses, features of kinetics of bleaching, RI...

  17. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

    2015-04-30

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

  18. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    International Nuclear Information System (INIS)

    Evora, M.C.; Araujo, J.R.; Ferreira, E.H.M.; Strohmeier, B.R.; Silva, L.G.A.; Achete, C.A.

    2015-01-01

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp 2 structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO 4 ·7H 2 O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful

  19. Comparison of the Raman spectra of ion irradiated soot and collected extraterrestrial carbon

    Science.gov (United States)

    Brunetto, R.; Pino, T.; Dartois, E.; Cao, A.-T.; d'Hendecourt, L.; Strazzulla, G.; Bréchignac, Ph.

    2009-03-01

    We use a low pressure flame to produce soot by-products as possible analogues of the carbonaceous dust present in diverse astrophysical environments, such as circumstellar shells, diffuse interstellar medium, planetary disks, as well as in our own Solar System. Several soot samples, displaying an initial chemical diversity from aromatic to aliphatic dominated material, are irradiated with 200-400 keV H +, He +, and Ar ++ ions, with fluences comprised between 10 14 and 10 16 ions/cm 2, to simulate expected radiation induced modification on extraterrestrial carbon. The evolution of the samples is monitored using Raman spectroscopy, before, during, and after irradiation. A detailed analysis of the first- and second-order Raman spectra is performed, using a fitting combination of Lorentzian and/or Gaussian-shaped bands. Upon irradiation, the samples evolve toward an amorphous carbon phase. The results suggest that the observed variations are more related to vacancy formation than ionization processes. A comparison with Raman spectra of extraterrestrial organic matter and other irradiation experiments of astrophysically relevant carbonaceous materials is presented. The results are consistent with previous experiments showing mostly amorphization of various carbonaceous materials. Irradiated soots have Raman spectra similar to those of some meteorites, IDPs, and Comet Wild 2 grains collected by the Stardust mission. Since the early-Sun expected irradiation fluxes sufficient for amorphization are compatible with accretion timescales, our results support the idea that insoluble organic matter (IOM) observed in primitive meteorites has experienced irradiation-induced amorphization prior to the accretion of the parent bodies, emphasizing the important role played by early solar nebula processing.

  20. Inhibition of potential lethal damage repair and related gene expression after carbon-ion beam irradiation to human lung cancer grown in nude mice

    International Nuclear Information System (INIS)

    Yashiro, Tomoyasu; Fujisawa, Takehiko; Koyama-Saegusa, Kumiko; Imai, Takashi; Miyamoto, Tadaaki

    2007-01-01

    Using cultured and nude mouse tumor cells (IA) derived from a human lung cancer, we previously demonstrated their radiosensitivity by focusing attention on the dynamics of tumor clonogens and the early and rapid survival recovery (potential lethal damage repair: PLD repair) occurring after X-ray irradiation. To the authors' knowledge, this is the first study demonstrating gene expression in association with PLD repair after carbon-ion beam or X-ray irradiation to cancer cells. In this study we tried to detect the mechanism of DNA damage and repair of the clonogens after X-ray or carbon-ion beam irradiation. At first, colony assay method was performed after irradiation of 12 Gy of X-ray or 5 Gy of carbon-ion beam to compare the time dependent cell survival of the IA cells after each irradiation pass. Second, to search the genes causing PLD repair after irradiation of X-ray or carbon-ion beam, we evaluated gene expressions by using semi-quantitative RT-PCR with the selected 34 genes reportedly related to DNA repair. The intervals from the irradiation were 0, 6, 12 and 24 hr for colony assay method, and 0, 3, 18 hr for RT-PCR method. From the result of survival assays, significant PLD repair was not observed in carbon-ion beam as compared to X-ray irradiation. The results of RT-PCR were as follows. The gene showing significantly higher expressions after X-ray irradiation than after carbon-ion beam irradiation was PCNA. The genes showing significantly lower expressions after X-ray irradiation rather than after carbon-ion beam irradiation were RAD50, BRCA1, MRE11A, XRCC3, CHEK1, MLH1, CCNB1, CCNB2 and LIG4. We conclude that PCNA could be a likely candidate gene for PLD repair. (author)

  1. Raman studies of the interactions of fibrous carbon nanomaterials with albumin

    Science.gov (United States)

    Wesełucha-Birczyńska, Aleksandra; Morajka, Krzysztof; Stodolak-Zych, Ewa; Długoń, Elżbieta; Dużyja, Maria; Lis, Tomasz; Gubernat, Maciej; Ziąbka, Magdalena; Błażewicz, Marta

    2018-05-01

    Adsorption or immobilization of proteins on synthetic surfaces is a key issue in the context of the biocompatibility of implant materials, especially those intended for the needs of cardiac surgery but also for the construction of biosensors or nanomaterials used as drug carriers. The subject of research was the analysis of Raman spectra of two types of fibrous carbon nanomaterials, of great potential for biomedical applications, incubated with human serum albumin (HSA). The first nanomaterial has been created on the layer of MWCNTs deposited by electrophoretic method (EPD) and then covered by thin film of pyrolytic carbon introduced by chemical vapor deposition process (CVD). The second material was formed from carbonized nanofibers prepared via electrospinning (ESCNFs) of polyacrylonitrile (PAN) precursor and then covered with pyrolytic carbon (CVD). The G-band blue-shift towards the position of about 1600 cm-1, observed for both studied surfaces, clearly indicates the albumin (HSA) adhesion to the surface. The G and G' (2D) peak shift was employed to assess the stress build up on the carbon nanomaterials. The surface nano- and micro-topography as well as the method of ordering the carbon nanomaterial has a significant influence on the mode of surface-protein interaction.

  2. The differential role of human macrophage in triggering secondary bystander effects after either gamma-ray or carbon beam irradiation.

    Science.gov (United States)

    Dong, Chen; He, Mingyuan; Tu, Wenzhi; Konishi, Teruaki; Liu, Weili; Xie, Yuexia; Dang, Bingrong; Li, Wenjian; Uchihori, Yukio; Hei, Tom K; Shao, Chunlin

    2015-07-10

    The abscopal effect could be an underlying factor in evaluating prognosis of radiotherapy. This study established an in vitro system to examine whether tumor-generated bystander signals could be transmitted by macrophages to further trigger secondary cellular responses after different irradiations, where human lung cancer NCI-H446 cells were irradiated with either γ-rays or carbon ions and co-cultured with human macrophage U937 cells, then these U937 cells were used as a bystander signal transmitter and co-cultured with human bronchial epithelial cells BEAS-2B. Results showed that U937 cells were only activated by γ-irradiated NCI-H446 cells so that the secondary injuries in BEAS-2B cells under carbon ion irradiation were weaker than γ-rays. Both TNF-α and IL-1α were involved in the γ-irradiation induced secondary bystander effect but only TNF-α contributed to the carbon ion induced response. Further assay disclosed that IL-1α but not TNF-α was largely responsible for the activation of macrophages and the formation of micronucleus in BEAS-2B cells. These data suggest that macrophages could transfer secondary bystander signals and play a key role in the secondary bystander effect of photon irradiation, while carbon ion irradiation has conspicuous advantage due to its reduced secondary injury. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. The bactericidal effect of carbon nanotube/agar composites irradiated with near-infrared light on Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Akasaka, Tsukasa, E-mail: akasaka@den.hokudai.ac.jp [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Matsuoka, Makoto [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Hashimoto, Takeshi [Meijo Nano Carbon Co. Ltd., Otsubashi bldg. 4F, 3-4-10 Marunouchi, Naka-ku, Nagoya 460-0002 (Japan); Abe, Shigeaki; Uo, Motohiro; Watari, Fumio [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan)

    2010-10-15

    Dental caries are mainly associated with oral pathogens, and Streptococcus mutans is a primary cariogenic organism. Many methods have been established to eliminate S. mutans from the oral cavity. This study aimed to evaluate the effect of carbon nanotube (CNT)/agar composites irradiated with near-infrared (NIR) light on S. mutans, as a potential photothermal antimicrobial nanotherapy. A colony-forming unit assay clearly showed that CNT/agar composites attain bactericidal activity after NIR light irradiation; this bactericidal activity is higher than that of graphite (GP)/agar and activated carbon (AC)/agar composites. Furthermore, it was observed that longer irradiation times immobilized S. mutans in the CNT/agar composite.

  4. The bactericidal effect of carbon nanotube/agar composites irradiated with near-infrared light on Streptococcus mutans

    International Nuclear Information System (INIS)

    Akasaka, Tsukasa; Matsuoka, Makoto; Hashimoto, Takeshi; Abe, Shigeaki; Uo, Motohiro; Watari, Fumio

    2010-01-01

    Dental caries are mainly associated with oral pathogens, and Streptococcus mutans is a primary cariogenic organism. Many methods have been established to eliminate S. mutans from the oral cavity. This study aimed to evaluate the effect of carbon nanotube (CNT)/agar composites irradiated with near-infrared (NIR) light on S. mutans, as a potential photothermal antimicrobial nanotherapy. A colony-forming unit assay clearly showed that CNT/agar composites attain bactericidal activity after NIR light irradiation; this bactericidal activity is higher than that of graphite (GP)/agar and activated carbon (AC)/agar composites. Furthermore, it was observed that longer irradiation times immobilized S. mutans in the CNT/agar composite.

  5. Role of carbon impurities on the surface morphology evolution of tungsten under high dose helium ion irradiation

    International Nuclear Information System (INIS)

    Al-Ajlony, A.; Tripathi, J.K.; Hassanein, A.

    2015-01-01

    The effect of carbon impurities on the surface evolution (e.g., fuzz formation) of tungsten (W) surface during 300 eV He ions irradiation was studied. Several tungsten samples were irradiated by He ion beam with a various carbon ions percentage. The presence of minute carbon contamination within the He ion beam was found to be effective in preventing the fuzz formation. At higher carbon concentration, the W surface was found to be fully covered with a thick graphitic layer on the top of tungsten carbide (WC) layer that cover the sample surface. Lowering the ion beam carbon percentage was effective in a significant reduction in the thickness of the surface graphite layer. Under these conditions the W surface was also found to be immune for the fuzz formation. The effect of W fuzz prevention by the WC formation on the sample surface was more noticeable when the He ion beam had much lower carbon (C) ions content (0.01% C). In this case, the fuzz formation was prevented on the vast majority of the W sample surface, while W fuzz was found in limited and isolated areas. The W surface also shows good resistance to morphology evolution when bombarded by high flux of pure H ions at 900 °C. - Highlights: • Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. • The effect of adding various percentage of carbon impurity to the He ion beam on the trend of W fuzz formation was studied. • Mitigation of W fuzz formation due to addition of small percentage of carbon to the He ion beam is reported. • The formation of long W nanowires due to He ion beam irradiation mixed with 0.01% carbon ions is reported.

  6. Tholins: Can They Provide a Substrate, Carbon and Nitrogen for Plant Production?

    Science.gov (United States)

    Wignarajah, Kanapathipillai; Khare, Bishun; Cruikshank, Dale; McKay, Christopher; Arnold, James O. (Technical Monitor)

    1999-01-01

    Tholin is a word coined to describe the entire class of complex organic solids produced in laboratory experiments where pre-biotic gaseous chemicals are subject to bombardment by high energy. The atomic composition of Titan tholin produced from 10 percent CH4 and 90 percent N2 in a simulation of Titan atmosphere irradiated by charged particles trapped in the magnetosphere of Saturn gave 67 percent C and 33 percent N. Hydrolysis of Titan tholin with 6N HCl produced a racemic mixture of biological and non-biological amino acids that was confirmed by GC/MS. Other tholins, that revealed the presence of amino acids, were UV tholin produced under possible primitive Earth conditions by irradiation of a mixture of gases (CH4, C2H6, NH3, H2S and liquid H2O) with long-wavelength ultraviolet light, representing the most abundant useful energy source for prebiological organic synthesis; Spark tholin in a crude simulation of Jupiter atmosphere using electrical discharge through a mixture of CH4, NH3, and H2O vapor. Pyrolytic GC/MS of Titan tholin produced more than one hundred organic compounds including saturated and unsaturated aliphatic hydrocarbons, substituted polycyclic aromatics, nitriles, amines, pyrroles, pyrazines, pyridines, pyrimidines, and the purine, adenine. Similar rich pyrolytic products were obtained with UV as well as Spark tholins. A range of two to four ring PAHs (Polycyclic Aromatic Hydrocarbons) in Spark as well as Titan tholins, some with one to four alkylation sites, were identified by two-step laser desorption/multiphoton ionization mass spectrometry and also confirmed by the synchronous fluorescence technique. Previous studies have demonstrated the potential for use of tholins as a source of carbon and energy by microbes. This paper describes studies that evaluate the potential for using different types of tholins as (a) a substrate for growing plants and (b) a source of carbon and nitrogen for plants. The data are interpreted in terms of the

  7. Displacement per atom profile in carbon nanotube bulk material under gamma irradiation

    International Nuclear Information System (INIS)

    Leyva, A.; Pinnera, I.; Leyva, D.; Cruz, C.; Abreu, Y.

    2011-01-01

    Taking into account the physical properties and the displacement threshold energy values reported in literature for C atoms in single and multiple walled carbon nanotubes, the effective atomic displacement cross-section in carbon nanotube bulk materials exposed to the gamma rays were calculated. Then, using the mathematical simulation of photons and particles transport in the matter, energy fluxes distribution of electrons and positrons within the irradiated object were also calculated. Finally, considering both results, the atomic displacement damage profiles inside the analyzed carbon nanotube bulk materials were determined. (Author)

  8. Positron annihilation study of graphite, glassy carbon and C60/C70 fullerene

    International Nuclear Information System (INIS)

    Hasegawa, Masayuki; Kajino, Masahiro; Yamaguchi, Sadae; Iwata, Tadao; Kuramoto, Eiichi; Takenaka, Minoru.

    1992-01-01

    ACAR (Angular Correlation of Annihilation Radiation) and positron lifetime measurements have been made on, HOPG (Highly Oriented Pyrolytic Graphite), isotropic fine-grained graphite, glassy carbons and C 60 /C 70 powder. HOPG showed marked bimodality along the c-axis and anisotropy in ACAR momentum distribution, which stem from characteristic annihilation between 'interlayer' positrons and π-electrons in graphite. ACAR curves of the isotropic graphite and glassy carbons are even narrower than that of HOPG perpendicular to the c-axis. Positron lifetime of 420 and 390 - 480 psec, much longer than that of 221 psec in HOPG, were observed for the isotropic graphite and glassy carbons respectively, which are due to positron trapping in structural voids in them. Positron lifetime and ACAR width (FWHM) can be well correlated to void sizes (1.7 to 5.0 nm) of glassy carbons which have been determined by small angle neutron (SAN) scattering measurements. ACAR curves and positron lifetime of C 60 /C 70 powder agree well with those of glassy carbons. This shows that positron wave functions extend, as in the voids of glassy carbons, much wider than open spaces of the octahedral interstices of the face-centered cubic (FCC) structure of C 60 crystal and strongly suggests positron trapping in the 'soccer ball' vacancy. Possible positron states in the carbon materials are discussed with a simple model of void volume-trapping. Preliminary results on neutron irradiation damage in HOPG are also presented. (author)

  9. Decomposition mechanism of melamine borate in pyrolytic and thermo-oxidative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hoffendahl, Carmen; Duquesne, Sophie; Fontaine, Gaëlle; Bourbigot, Serge, E-mail: serge.bourbigot@ensc-lille.fr

    2014-08-20

    Highlights: • Decomposition of melamine borate in pyrolytic and thermo-oxidative conditions was investigated. • With increasing temperature, orthoboric acid forms boron oxide releasing water. • Melamine decomposes evolving melamine, ammonia and other fragments. • Boron oxide is transformed into boron nitride and boron nitride-oxide structures through presence of ammonia. - Abstract: Decomposition mechanism of melamine borate (MB) in pyrolytic and thermo-oxidative conditions is investigated in the condensed and gas phases using solid state NMR ({sup 13}C and {sup 11}B), X-ray photoelectron spectroscopy (XPS), pyrolysis-gas chromatography–mass spectrometry (py-GCMS) and thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TGA–FTIR). It is evidenced that orthoboric acid dehydrates to metaboric and then to boron oxide. The melamine is partially sublimated. At the same time, melamine condensates, i.e., melem and melon are formed. Melon is only formed in thermo-oxidative conditions. At higher temperature, melem and melon decompose releasing ammonia which reacts with the boron oxide to form boron nitride (BN) and BNO structures.

  10. Simulation calculations of physical sputtering and reflection coefficient of plasma-irradiated carbon surface

    International Nuclear Information System (INIS)

    Kawamura, T.; Ono, T.; Yamamura, Y.

    1994-08-01

    Physical sputtering yields from the carbon surface irradiated by the boundary plasma are obtained with the use of a Monte Carlo simulation code ACAT. The yields are calculated for many random initial energy and angle values of incident protons or deuterons with a Maxwellian velocity distribution, and then averaged. Here the temperature of the boundary plasma, the sheath potential and the angle δ between the magnetic field line and the surface normal are taken into account. A new fitting formula for an arrangement of the numerical data of sputtering yield is introduced, in which six fitting parameters are determined from the numerical results and listed. These results provide a way to estimate the erosion of carbon materials irradiated by boundary plasma. The particle reflection coefficients for deuterons and their neutrals from a carbon surface are also calculated by the same code and presented together with, for comparison, that for the case of monoenergetic normal incidence. (author)

  11. Superconducting and normal state properties of carbon doped and neutron irradiated MgB2

    International Nuclear Information System (INIS)

    Wilke, R.H.T.; Samuely, P.; Szabo, P.; Holanova, Z.; Bud'ko, S.L.; Canfield, P.C.; Finnemore, D.K.

    2007-01-01

    Current research in MgB 2 focuses on the effects various types of perturbations have on the superconducting properties of this novel two-gap superconductor. In this article we summarize the effects of carbon doping and neutron irradiation in bulk MgB 2 . Low levels of carbon doping and light neutron irradiation result in significant enhancements in H c2 . At high fluences, where superconductivity is nearly fully suppressed, superconductivity can be restored through post exposure annealing. However, this results in a change in the interdependencies of the normal state and superconducting properties (ρ 0 , T c , H c2 ), with little or no enhancement in H c2

  12. Evaluation of a combination tumor treatment using thermo-triggered liposomal drug delivery and carbon ion irradiation.

    Science.gov (United States)

    Kokuryo, Daisuke; Aoki, Ichio; Yuba, Eiji; Kono, Kenji; Aoshima, Sadahito; Kershaw, Jeff; Saga, Tsuneo

    2017-07-01

    The combination of radiotherapy with chemotherapy is one of the most promising strategies for cancer treatment. Here, a novel combination strategy utilizing carbon ion irradiation as a high-linear energy transfer (LET) radiotherapy and a thermo-triggered nanodevice is proposed, and drug accumulation in the tumor and treatment effects are evaluated using magnetic resonance imaging relaxometry and immunohistology (Ki-67, n = 15). The thermo-triggered liposomal anticancer nanodevice was administered into colon-26 tumor-grafted mice, and drug accumulation and efficacy was compared for 6 groups (n = 32) that received or did not receive the radiotherapy and thermo trigger. In vivo quantitative R 1 maps visually demonstrated that the multimodal thermosensitive polymer-modified liposomes (MTPLs) can accumulate in the tumor tissue regardless of whether the region was irradiated by carbon ions or not. The tumor volume after combination treatment with carbon ion irradiation and MTPLs with thermo-triggering was significantly smaller than all the control groups at 8 days after treatment. The proposed strategy of combining high-LET irradiation and the nanodevice provides an effective approach for minimally invasive cancer treatment. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. The pyrolytic-plasma method and the device for the utilization of hazardous waste containing organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Opalińska, Teresa [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Wnęk, Bartłomiej, E-mail: bartlomiej.wnek@itr.org.pl [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Witowski, Artur; Juszczuk, Rafał; Majdak, Małgorzata [Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw (Poland); Bartusek, Stanilav [VŠB—Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava − Poruba Czech Republic (Czech Republic)

    2016-11-15

    Highlights: • A first stage of the process of waste utilization consisted in pyrolysis of waste. • Then the pyrolytic gas was oxidized with a use of non-equilibrium plasma. • The device for the process implementation was built and characterized. • Correctness of the device operation was proven with a use of the decomposition of PE. • Usefulness of the method was proven in the process of utilization of EW. - Abstract: This paper is focused on the new method of waste processing. The waste, including hazardous waste, contain organic compounds. The method consists in two main processes: the pyrolysis of waste and the oxidation of the pyrolytic gas with a use of non-equilibrium plasma. The practical implementation of the method requires the design, construction and testing of the new device in large laboratory scale. The experiments were carried out for the two kinds of waste: polyethylene as a model waste and the electronic waste as a real waste. The process of polyethylene decomposition showed that the operation of the device is correct because 99.74% of carbon moles contained in the PE samples was detected in the gas after the process. Thus, the PE samples practically were pyrolyzed completely to hydrocarbons, which were completely oxidized in the plasma reactor. It turned out that the device is useful for decomposition of the electronic waste. The conditions in the plasma reactor during the oxidation process of the pyrolysis products did not promote the formation of PCDD/Fs despite the presence of the oxidizing conditions. An important parameter determining the efficiency of the oxidation of the pyrolysis products is gas temperature in the plasma reactor.

  14. Advances on simultaneous desulfurization and denitrification using activated carbon irradiated by microwaves.

    Science.gov (United States)

    Ma, Shuang-Chen; Gao, Li; Ma, Jing-Xiang; Jin, Xin; Yao, Juan-Juan; Zhao, Yi

    2012-06-01

    This paper describes the research background and chemistry of desulfurization and denitrification technology using microwave irradiation. Microwave-induced catalysis combined with activated carbon adsorption and reduction can reduce nitric oxide to nitrogen and sulfur dioxide to sulfur from flue gas effectively. This paper also highlights the main drawbacks of this technology and discusses future development trends. It is reported that the removal of sulfur dioxide and nitric oxide using microwave irradiation has broad prospects for development in the field of air pollution control.

  15. Growth and field emission properties of one-dimensional carbon composite structure consisting of vertically aligned carbon nanotubes and nanocones

    International Nuclear Information System (INIS)

    Zhang Hongxin; Feng, Peter X; Fonseca, Luis; Morell, Gerardo; Makarov, Vladimir I; Weiner, Brad R

    2009-01-01

    A simple approach is demonstrated for quickly growing a large-area aligned carbon composite nanostructure consisting of vertically aligned nanotubes and nanocones by the catalyst-assisted pulsed laser deposition techniques. The pyrolytic graphite was used as carbon source. The carbon nanocones were first grown on the molybdenum substrate with Ni catalysts. The carbon nanotubes have a uniform shape and length, aligned vertically on carbon nanocones, and the average diameter is about 7 nm. The special carbon composite arrays exhibit excellent field emission behaviours. The long-term field emission current stability of the one-dimensioned carbon nanostructure has also been investigated. No obvious current density decay was observed after a 10-day continuous experiment, indicating the super stability of the sample as cathode material.

  16. DAMAGE IN MOLYBDENUM ASSOCIATED WITH NEUTRON IRRADIATION AND SUBSEQUENT POST-IRRADIATION ANNEALING

    Energy Technology Data Exchange (ETDEWEB)

    Mastel, B.

    1963-07-23

    Molybdemum containing carbon was studied in an attempt to establish the combined effect of impurity content and neutron irradiation on the properties and structure of specific metals. Molybdenum foils were punched into discs and heat treated in vacuum. They were then slow-cooled and irradiated. After irradiation and subsequent decay of radioactivity to a low level the foils were subjected to x-ray diffraction measurements. Cold-worked foils with less than 10 ppm carbon showed no change in microstructure due to irradiation. Molybdenum foils that were annealed prior to irradiation showed spot defects. In foils containing up to 500 ppm carbon, it was concluded that the small loops present after irradiation are due to the clustering of point defects at interstitial carbon atoms, followed by collapse to form a dislocation loop. The amount of lattice expansion after irradiation was strongly dependent on impurity content. Neutron irradiation was found to reduce the number of active slip systems. (M.C.G.)

  17. Quantitative evaluation of potential irradiation geometries for carbon-ion beam grid therapy.

    Science.gov (United States)

    Tsubouchi, Toshiro; Henry, Thomas; Ureba, Ana; Valdman, Alexander; Bassler, Niels; Siegbahn, Albert

    2018-03-01

    Radiotherapy using grids containing cm-wide beam elements has been carried out sporadically for more than a century. During the past two decades, preclinical research on radiotherapy with grids containing small beam elements, 25 μm-0.7 mm wide, has been performed. Grid therapy with larger beam elements is technically easier to implement, but the normal tissue tolerance to the treatment is decreasing. In this work, a new approach in grid therapy, based on irradiations with grids containing narrow carbon-ion beam elements was evaluated dosimetrically. The aim formulated for the suggested treatment was to obtain a uniform target dose combined with well-defined grids in the irradiated normal tissue. The gain, obtained by crossfiring the carbon-ion beam grids over a simulated target volume, was quantitatively evaluated. The dose distributions produced by narrow rectangular carbon-ion beams in a water phantom were simulated with the PHITS Monte Carlo code. The beam-element height was set to 2.0 cm in the simulations, while the widths varied from 0.5 to 10.0 mm. A spread-out Bragg peak (SOBP) was then created for each beam element in the grid, to cover the target volume with dose in the depth direction. The dose distributions produced by the beam-grid irradiations were thereafter constructed by adding the dose profiles simulated for single beam elements. The variation of the valley-to-peak dose ratio (VPDR) with depth in water was thereafter evaluated. The separation of the beam elements inside the grids were determined for different irradiation geometries with a selection criterion. The simulated carbon-ion beams remained narrow down to the depths of the Bragg peaks. With the formulated selection criterion, a beam-element separation which was close to the beam-element width was found optimal for grids containing 3.0-mm-wide beam elements, while a separation which was considerably larger than the beam-element width was found advantageous for grids containing 0.5-mm

  18. Irradiation performance of AGR-1 high temperature reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Demkowicz; John D. Hunn; Robert N. Morris; Charles A. Baldwin; Philip L. Winston; Jason M. Harp; Scott A. Ploger; Tyler Gerczak; Isabella J. van Rooyen; Fred C. Montgomery; Chinthaka M. Silva

    2014-10-01

    The AGR-1 experiment contained 72 low-enriched uranium oxide/uranium carbide TRISO-coated particle fuel compacts in six capsules irradiated to burnups of 11.2 to 19.5% FIMA, with zero TRISO coating failures detected during the irradiation. The irradiation performance of the fuel–including the extent of fission product release and the evolution of kernel and coating microstructures–was evaluated based on detailed examination of the irradiation capsules, the fuel compacts, and individual particles. Fractional release of 110mAg from the fuel compacts was often significant, with capsule-average values ranging from 0.01 to 0.38. Analysis of silver release from individual compacts indicated that it was primarily dependent on fuel temperature history. Europium and strontium were released in small amounts through intact coatings, but were found to be significantly retained in the outer pyrocrabon and compact matrix. The capsule-average fractional release from the compacts was 1×10 4 to 5×10 4 for 154Eu and 8×10 7 to 3×10 5 for 90Sr. The average 134Cs release from compacts was <3×10 6 when all particles maintained intact SiC. An estimated four particles out of 2.98×105 experienced partial cesium release due to SiC failure during the irradiation, driving 134Cs release in two capsules to approximately 10 5. Identification and characterization of these particles has provided unprecedented insight into the nature and causes of SiC coating failure in high-quality TRISO fuel. In general, changes in coating morphology were found to be dominated by the behavior of the buffer and inner pyrolytic carbon (IPyC), and infrequently observed SiC layer damage was usually related to cracks in the IPyC. Palladium attack of the SiC layer was relatively minor, except for the particles that released cesium during irradiation, where SiC corrosion was found adjacent to IPyC cracks. Palladium, silver, and uranium were found in the SiC layer of irradiated particles, and characterization

  19. Raman spectroscopic investigations of swift heavy ion irradiation effects in single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Olejniczak, A.; Skuratov, V.A.; Lukaszewicz, J.P.

    2013-01-01

    In this study, we report the results on swift heavy ion irradiation effects in single-walled carbon nanotubes (SWNTs). Buckypapers, prepared of CVD grown, SWNTs were irradiated at room temperature with 167 MeV Xe ions to fluences in the range of 6×10 11 - 6.5×10 13 cm -2 and investigated using Raman spectroscopy. We observed a rich set of features in the intermediate frequency mode region. Some of them, being defect-induced, resembled fairly well the phonon density of states (DOS) of nanocrystalline glassy carbon. Analysis of the RBM modes has shown that the broader metallic tubes are characterized by higher radiation stability than thinner semiconducting ones. (authors)

  20. A pseudo-curved oriented pyrolytic graphite neutron monochromator

    International Nuclear Information System (INIS)

    Ettedgui, H.; Gurewitz, E.; Pinto, H.

    1979-03-01

    A pseudo-curved neutron monochromator with a continuously variable curvature was constructed with four flat pieces of oriented pyrolytic graphite (OPG). Curvatures which yield maximum diffracted intensities were determined for neutrons of wavelengths 1 A and 2.4 A. The increase of the intensity relatively to that of a flat monochromator is by a factor of 2 and 1.5, for 1 A and 2.4 A, respectively. The neutron flux at three positions along the neutron path was determined by gold foils activation and compared with the flux from flat monochromators of OPG and copper

  1. Effects of Ru(CO)3Cl-glycinate on the developmental toxicities induced by X-ray and carbon-ion irradiation in zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rong [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Song, Jing’e [School/Hospital of stomatology, Lanzhou University, Lanzhou 730000 (China); Si, Jing [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Zhang, Hong, E-mail: zhangh@impcas.ac.cn [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Liu, Bin [School/Hospital of stomatology, Lanzhou University, Lanzhou 730000 (China); Gan, Lu; Zhou, Xin [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); and others

    2016-11-15

    Highlights: • CORM-3 pretreatment could significantly inhibit the X-ray irradiation-induced developmental toxicity and apoptosis with ROS generation. • CORM-3 pretreatment showed little effect on carbon-ion irradiation-induced developmental toxicity and apoptosis without ROS generation. • CORM-3 could inhibit apoptosis induced by ionizing radiation with low-LET as an effective ROS scavenger. • CORM-3 could suppress apoptosis and DNA damage by inhibiting the activation of P53 and the mitochondrial apoptotic pathway. - Abstract: The inhibitory effects of carbon monoxide (CO), generated by Ru(CO){sub 3}Cl-glycinate [CO-releasing molecule (CORM-3)], on developmental toxicity in zebrafish embryos induced by ionizing radiation with different linear energy transfer (LET) were studied. Zebrafish embryos at 5 h post-fertilization were irradiated with X-ray (low-LET) and carbon-ion (high-LET) with or without pretreatment of CORM-3 1 h before irradiation. CORM-3 pre-treatment showed a significant inhibitory effect on X-ray irradiation-induced developmental toxicity, but had little effect on carbon-ion irradiation-induced developmental toxicity. X-ray irradiation-induced significant increase in ROS levels and cell apoptosis could be modified by CORM-3 pretreatment. However, embryos exposed to carbon-ion irradiation showed significantly increase of cell apoptosis without obvious ROS generation, which could not be attenuated by CORM-3 pretreatment. CORM-3 could inhibit apoptosis induced by ionizing radiation with low-LET as an effective ROS scavenger. The expression of pro-apoptotic genes increased significantly after X-ray irradiation, but increased expression was reduced markedly when CORM-3 was applied before irradiation. Moreover, the protein levels of P53 and γ-H2AX increased markedly after X-ray irradiation, which could be modified by the presence of CORM-3. The protective effect of CORM-3 on X-ray irradiation occurred mainly by suppressing ROS generation and DNA

  2. Mesoscopic self-organization of a self-assembled supramolecular rectangle on highly oriented pyrolytic graphite and Au(111) surfaces.

    Science.gov (United States)

    Gong, Jian-Ru; Wan, Li-Jun; Yuan, Qun-Hui; Bai, Chun-Li; Jude, Hershel; Stang, Peter J

    2005-01-25

    A self-assembled supramolecular metallacyclic rectangle was investigated with scanning tunneling microscopy on highly oriented pyrolytic graphite and Au(111) surfaces. The rectangles spontaneously adsorb on both surfaces and self-organize into well ordered adlayers. On highly oriented pyrolytic graphite, the long edge of the rectangle stands on the surface, forming a 2D molecular network. In contrast, the face of the rectangle lays flat on the Au(111) surface, forming linear chains. The structures and intramolecular features obtained through high-resolution scanning tunneling microscopy imaging are discussed.

  3. Acceptance Test Data for the AGR-5/6/7 Irradiation Test Fuel Composite Defective IPyC Fraction and Pyrocarbon Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, John A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schumacher, Austin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-01

    Coated particle composite J52R-16-98005 was produced by Babcock and Wilcox Technologies (BWXT) as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR). This composite was comprised of four coated particle fuel batches J52O-16-93165B (26%), 93168B (26%), 93169B (24%), and 93170B (24%), chosen based on the Quality Control (QC) data acquired for each individual candidate AGR-5/6/7 batch. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT Lot J52R-16-69317 containing a mixture of 15.5%-enriched uranium carbide and uranium oxide (UCO). The TRISO coatings consisted of four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. The TRISO-coated particle batches were sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batches were designated by appending the letter A to the end of the batch number (e.g., 93165A). Secondary upgrading by sieving was performed on the A-designated batches to remove particles with missing or very-thin buffer layers that were identified during previous analysis of the individual batches for defective IPyC, as reported in the acceptance test data report for the AGR-5/6/7 production batches [Hunn et al. 2017]. The additionally-upgraded batches were designated by appending the letter B to the end of the batch number (e.g., 93165B).

  4. Inhibitory effects of prior low-dose X-ray irradiation on carbon tetrachloride-induced hepatopathy in acatalasemic mice

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Kataoka, Takahiro; Taguchi, Takehito; Wang, Da-Hong; Mori, Shuji; Hanamoto, Katsumi; Kira, Shohei; Nomura, Takaharu

    2004-01-01

    The catalase activities in blood and organs of the acatalasemic (C3H/AnLCs b Cs b ) mouse of C3H strain are lower than those of the normal (C3H/AnLCs a Cs a ) mouse. We examined the effects of prior low-dose (0.5 Gy) X-ray irradiation, which reduced the oxidative damage under carbon tetrachloride-induced hepatopathy in the acatalasemic or normal mice. The acatalasemic mice showed a significantly lower catalase activity and a significantly higher glutathione peroxidase activity compared with those in the normal mice. Moreover, low-dose irradiation increased the catalase activity in the acatalasemic mouse liver to a level similar to that of the normal mouse liver. Pathological examinations and analyses of blood glutamic oxaloacetic and glutamic pyruvic transaminase activity and lipid peroxide levels showed that carbon tetrachloride induced hepatopathy was inhibited by low-dose irradiation. These findings may indicate that the free radical reaction induced by the lack of catalase and the administration of carbon tetrachloride is more properly neutralized by high glutathione peroxidase activity and low-dose irradiation in the acatalasemic mouse liver. (author)

  5. Radiosensitivity of Patient-Derived Glioma Stem Cell 3-Dimensional Cultures to Photon, Proton, and Carbon Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chiblak, Sara; Tang, Zili [German Cancer Consortium, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion Therapy Center, Heidelberg Institute of Radiation Oncology, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Campos, Benito; Gal, Zoltan; Unterberg, Andreas [Division of Neurological Research, Department of Neurosurgery, University of Heidelberg Medical School, Heidelberg (Germany); Debus, Jürgen [German Cancer Consortium, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion Therapy Center, Heidelberg Institute of Radiation Oncology, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany); Herold-Mende, Christel [Division of Neurological Research, Department of Neurosurgery, University of Heidelberg Medical School, Heidelberg (Germany); Abdollahi, Amir, E-mail: a.amir@dkfz.de [German Cancer Consortium, Heidelberg (Germany); Molecular and Translational Radiation Oncology, Heidelberg Ion Therapy Center, Heidelberg Institute of Radiation Oncology, University of Heidelberg Medical School and National Center for Tumor Diseases, German Cancer Research Center, Heidelberg (Germany)

    2016-05-01

    Purpose: To investigate the radiosensitivity of primary glioma stem cell (GSC) cultures with different CD133 status in a 3-dimensional (3D) model after photon versus proton versus carbon irradiation. Methods and Materials: Human primary GSC spheroid cultures were established from tumor specimens of six consented glioblastoma patients. Human U87MG was used as a classical glioblastoma radioresistant cell line. Cell suspensions were generated by mechanical dissociation of GSC spheroids and embedded in a semi-solid 3D matrix before irradiation. Spheroid-like colonies were manually counted by microscopy. Cells were also recovered and quantified by fluorescence. CD133 expression and DNA damage were evaluated by flow cytometry. Results: The fraction of CD133{sup +} cells varied between 0.014% and 96% in the six GSC cultures and showed a nonsignificant correlation with plating efficiency and survival fractions. The 4 most photon-radioresistant GSC cultures were NCH644, NCH421k, NCH441, and NCH636. Clonogenic survival for proton irradiation revealed relative biologic effectiveness (RBE) in the range of 0.7-1.20. However, carbon irradiation rendered the photon-resistant GSC cultures sensitive, with average RBE of 1.87-3.44. This effect was partly attributed to impaired capability of GSC to repair carbon ion–induced DNA double-strand breaks as determined by residual DNA repair foci. Interestingly, radiosensitivity of U87 cells was comparable to GSC cultures using clonogenic survival as the standard readout. Conclusions: Carbon irradiation is effective in GSC eradication with similar RBE ranges approximately 2-3 as compared with non-stem GSC cultures (U87). Our data strongly suggest further exploration of GSC using classic radiobiology endpoints such as the here-used 3D clonogenic survival assay and integration of additional GSC-specific markers.

  6. Radiosensitivity of Patient-Derived Glioma Stem Cell 3-Dimensional Cultures to Photon, Proton, and Carbon Irradiation

    International Nuclear Information System (INIS)

    Chiblak, Sara; Tang, Zili; Campos, Benito; Gal, Zoltan; Unterberg, Andreas; Debus, Jürgen; Herold-Mende, Christel; Abdollahi, Amir

    2016-01-01

    Purpose: To investigate the radiosensitivity of primary glioma stem cell (GSC) cultures with different CD133 status in a 3-dimensional (3D) model after photon versus proton versus carbon irradiation. Methods and Materials: Human primary GSC spheroid cultures were established from tumor specimens of six consented glioblastoma patients. Human U87MG was used as a classical glioblastoma radioresistant cell line. Cell suspensions were generated by mechanical dissociation of GSC spheroids and embedded in a semi-solid 3D matrix before irradiation. Spheroid-like colonies were manually counted by microscopy. Cells were also recovered and quantified by fluorescence. CD133 expression and DNA damage were evaluated by flow cytometry. Results: The fraction of CD133"+ cells varied between 0.014% and 96% in the six GSC cultures and showed a nonsignificant correlation with plating efficiency and survival fractions. The 4 most photon-radioresistant GSC cultures were NCH644, NCH421k, NCH441, and NCH636. Clonogenic survival for proton irradiation revealed relative biologic effectiveness (RBE) in the range of 0.7-1.20. However, carbon irradiation rendered the photon-resistant GSC cultures sensitive, with average RBE of 1.87-3.44. This effect was partly attributed to impaired capability of GSC to repair carbon ion–induced DNA double-strand breaks as determined by residual DNA repair foci. Interestingly, radiosensitivity of U87 cells was comparable to GSC cultures using clonogenic survival as the standard readout. Conclusions: Carbon irradiation is effective in GSC eradication with similar RBE ranges approximately 2-3 as compared with non-stem GSC cultures (U87). Our data strongly suggest further exploration of GSC using classic radiobiology endpoints such as the here-used 3D clonogenic survival assay and integration of additional GSC-specific markers.

  7. Study of the effect of gamma irradiation on carbon black loaded low-density polyethylene films

    International Nuclear Information System (INIS)

    Salem, M.A.; Hussein, A.; El-Ahdal, M.A.

    2003-01-01

    The effect of gamma irradiation on the tensile and physico-chemical properties of low-density polyethylene (LDPE) films loaded with different concentrations of carbon black (C.B) has been studied. The results showed that the behavior of the samples during gamma irradiation is complicated and this may be due to scission and the interaction between oxidation and crosslinking processes. The tensile properties are modified by the presence of carbon black. Film sample containing 7% C.B was found to exhibit a nearly stabilized tensile behavior with radiation dose, which allows to use this formulation in packaging for food sterilization and in preservation of weak cobalt-gamma sources. (author)

  8. Direct synthesis of graphitic mesoporous carbon from green phenolic resins exposed to subsequent UV and IR laser irradiations

    Science.gov (United States)

    Sopronyi, Mihai; Sima, Felix; Vaulot, Cyril; Delmotte, Luc; Bahouka, Armel; Matei Ghimbeu, Camelia

    2016-01-01

    The design of mesoporous carbon materials with controlled textural and structural features by rapid, cost-effective and eco-friendly means is highly demanded for many fields of applications. We report herein on the fast and tailored synthesis of mesoporous carbon by UV and IR laser assisted irradiations of a solution consisting of green phenolic resins and surfactant agent. By tailoring the UV laser parameters such as energy, pulse repetition rate or exposure time carbon materials with different pore size, architecture and wall thickness were obtained. By increasing irradiation dose, the mesopore size diminishes in the favor of wall thickness while the morphology shifts from worm-like to an ordered hexagonal one. This was related to the intensification of phenolic resin cross-linking which induces the reduction of H-bonding with the template as highlighted by 13C and 1H NMR. In addition, mesoporous carbon with graphitic structure was obtained by IR laser irradiation at room temperature and in very short time periods compared to the classical long thermal treatment at very high temperatures. Therefore, the carbon texture and structure can be tuned only by playing with laser parameters, without extra chemicals, as usually required. PMID:28000781

  9. Histological and elemental changes in the rat brain after local irradiation with carbon ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Sentaro; Sun, Xue-Zhi; Kubota, Yoshihisa; Takai, Nobuhiko; Nojima, Kumie [National Inst. of Radiological Sciences, Chiba (Japan)

    2002-06-01

    The left cerebral hemispheres of adult Sprague-Dawley rat brains were irradiated at doses of 30, 50, or 100 Gy with charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). The spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. A histological examination showed that necrotic tissue damage, hemorrhage in the thalamus, and vasodilatations around the necrotic region were induced at 8 weeks after 100 Gy irradiation. The regions with tissue damage correlated well with those expected from the radiation-dose distribution, indicating an advantage of charged carbon particles for irradiating restricted brain regions. An X-ray fluorescent analysis demonstrated a decrease in the concentrations of K and P, and an increase in the concentrations of Cl, Fe, Zn in the damaged region at 8 weeks post-irradiation, though no significant changes were observed before 4 weeks of post-irradiation. This may indicate that even the very high radiation doses used here did not induce acute and immediate neuronal cell death, in contrast with ischemic brain injury where acute neuronal cell death occurred and the elemental concentrations changed within a day after the induction of ischemia. (author)

  10. CVD mechanism of pyrolytic boron nitride

    International Nuclear Information System (INIS)

    Tanji, H.; Monden, K.; Ide, M.

    1987-01-01

    Pyrolytic boron nitride (P-BN) has become a essential material for III-V compound semiconductor manufacturing process. As the demand from electronics industry for larger single crystals increases, the demand for larger and more economical P-BN components is growing rapidly. P-BN is manufactured by low pressure CVD using boron-trihalides and ammonia as the reactants. In spite that P-BN has been in the market for quite a long time, limited number of fundamental studies regarding the kinetics and the formation mechanism of P-BN have been reported. As it has been demonstrated in CVD of Si, knowledge and both theoretical and empirical modeling of CVD process can be applied to improve the deposition technology and to give more uniform deposition with higher efficiency, and it should also apply to the deposition of P-BN

  11. High efficient and continuous surface modification of carbon fibers with improved tensile strength and interfacial adhesion

    Science.gov (United States)

    Sun, Jingfeng; Zhao, Feng; Yao, Yue; Jin, Zhen; Liu, Xu; Huang, Yudong

    2017-08-01

    Most of the surface modification technologies for carbon fibers, no matter in laboratory scale or for commercial manufacture, are accompanied by a simultaneous decrease in tensile strength. In this paper, a feasible and high efficient strategy for carbon fiber treatment which could obviously improve both tensile strength and interfacial adhesion was proposed. Continuously moving carbon fibers were treated with atmospheric helium plasma for 1 min, followed by a 5 min pyrolytic carbon deposition using ethanol as precursor at 800 °C. The effects of the new approach were characterized by SEM, AFM, nanoindentation, XPS, Raman, wettability analysis, single fiber tensile strength testing and single fiber pull-out testing. After modification, pyrolytic carbon coating was deposited on the fiber surface uniformly, and the roughness and surface energy increased significantly. The single fiber tensile testing results indicate that the resulting fiber strength increased 15.7%, rising from 3.13 to 3.62 GPa. Meanwhile, the interfacial shear strength of its epoxy composites increased from 65.3 to 83.5 MPa. The comparative studies of carbon fibers modified with commercial anodic oxidation and sizing were also carried out. The results demonstrate that the new method can be utilized in the carbon fiber manufacture process and is more efficient than the traditional approaches.

  12. High energy (MeV) ion-irradiated π-conjugated polyaniline: Transition from insulating state to carbonized conducting state

    International Nuclear Information System (INIS)

    Park, S.K.; Lee, S.Y.; Lee, C.S.; Kim, H.M.; Joo, J.; Beag, Y.W.; Koh, S.K.

    2004-01-01

    High energy (MeV) C 2+ , F 2+ , and Cl 2+ ions were irradiated onto π-conjugated polyaniline emeraldine base (PAN-EB) samples. The energy of an ion beam was controlled to a range of 3-4.5 MeV, with the ion dosage varying from 1x10 12 to 1x10 16 ions/cm 2 . The highest dc conductivity (σ dc ) at room temperature was measured to be ∼60 S/cm for 4.5 MeV Cl 2+ ion-irradiated PAN-EB samples with a dose of 1x10 16 ions/cm 2 . We observed the transition of high energy ion-irradiated PAN-EB samples from insulating state to conducting state as a function of ion dosage based on σ dc and its temperature dependence. The characteristic peaks of the Raman spectrum of the PAN-EB samples were reduced, while the D-peak (disordered peak) and the G peak (graphitic peak) appeared as the ion dose increased. From the analysis of the D and G peaks of the Raman spectra of the systems compared to multiwalled carbon nanotubes, ion-irradiated graphites, and annealed carbon films, the number of the clusters of hexagon rings with conducting sp 2 -bonded carbons increased with ion dosage. We also observed the increase in the size of the nanocrystalline graphitic domain of the systems with increasing ion dosage. The intensity of normalized electron paramagnelic resonance signal also increased in correlation with ion dose. The results of this study demonstrate that π-conjugated pristine PAN-EB systems changed from insulating state to carbonized conducting state through high energy ion irradiation with high ion dosage

  13. PIE of nuclear grade SiC/SiC flexural coupons irradiated to 10 dpa at LWR temperature

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    Silicon carbide fiber-reinforced SiC matrix (SiC/SiC) composites are being actively investigated for accident-tolerant core structures of light water reactors (LWRs). Owing to the limited number of irradiation studies previously conducted at LWR-coolant temperature, this study examined SiC/SiC composites following neutron irradiation at 230–340°C to 2.0 and 11.8 dpa in the High Flux Isotope Reactor. The investigated materials are chemical vapor infiltrated (CVI) SiC/SiC composites with three different reinforcement fibers. The fiber materials were monolayer pyrolytic carbon (PyC)-coated Hi-NicalonTM Type-S (HNS), TyrannoTM SA3 (SA3), and SCS-UltraTM (SCS) SiC fibers. The irradiation resistance of these composites was investigated based on flexural behavior, dynamic Young’s modulus, swelling, and microstructures. There was no notable mechanical properties degradation of the irradiated HNS and SA3 SiC/SiC composites except for reduction of the Young’s moduli by up to 18%. The microstructural stability of these composites supported the absence of degradation. In addition, no progressive swelling from 2.0 to 11.8 dpa was confirmed for these composites. On the other hand, the SCS composite showed significant mechanical degradation associated with cracking within the fiber. This study determined that SiC/SiC composites with HNS or SA3 SiC/SiC fibers, a PyC interphase, and a CVI SiC matrix retain their properties beyond the lifetime dose for LWR fuel cladding at the relevant temperature.

  14. Repair of skin damage during fractionated irradiation with gamma rays and low-LET carbon ions

    International Nuclear Information System (INIS)

    Ando, Koichi; Koike, Sachiko; Uzawa, Akiko; Takai, Nobuhiko; Fukawa, Takeshi; Furusawa, Yoshiya; Aoki, Mizuho; Hirayama, Ryoichi

    2006-01-01

    In clinical use of carbon-ion beams, a deep-seated tumor is irradiated with a Spread-Out Bragg peak (SOBP) with a high-linear energy transfer (LET) feature, whereas surface skin is irradiated with an entrance plateau, the LET of which is lower than that of the peak. The repair kinetics of murine skin damage caused by an entrance plateau of carbon ions was compared with that caused by photons using a scheme of daily fractionated doses followed by a top-up dose. Right hind legs received local irradiations with either 20 keV/μm carbon ions or γ rays. The skin reaction of the irradiated legs was scored every other day up to Day 35 using a scoring scale that consisted of 10 steps, ranging from 0.5 to 5.0. An isoeffect dose to produce a skin reaction score of 3.0 was used to obtain a total dose and a top-up dose for each fractionation. Dependence on a preceding dose and on the time interval of a top-up dose was examined using γ rays. For fractionated γ rays, the total dose linearly increased while the top-up dose linearly decreased with an increase in the number of fractions. The magnitude of damage repair depended on the size of dose per fraction, and was larger for 5.2 Gy than 12.5 Gy. The total dose of carbon ions with 5.2 Gy per fraction did not change till 2 fractions, but abruptly increased at the 3rd fraction. Factors such as rapid repopulation, induced repair and cell cycle synchronization are possible explanations for the abrupt increase. As an abrupt increase/decrease of normal tissue damage could be caused by changing the number of fractions in carbon-ion radiotherapy, we conclude that, unlike photon therapy, skin damage should be carefully studied when the number of fractions is changed in new clinical trials. (author)

  15. Behavior of carbon readsorbed on tungsten during low energy Ar ion irradiation at elevated temperatures

    International Nuclear Information System (INIS)

    Pranevicius, L.; Pranevicius, L.L.; Milcius, D.; Templier, C.; Bobrovaite, B.

    2008-01-01

    A study of the behavior of carbon sputtered and readsorbed after scattering collisions with particles of surrounding gas on the tungsten surface affected by Ar ion irradiation with the flux equal to 2 x 10 16 cm -2 s -1 extracted from plasma under 300 V negative bias voltage in the temperature range 370-870 K was performed. The dependence of the W sample weight change on the working gas pressure in the range 0.1-10 Pa was registered and the information was deduced about prevailing sputtering-redeposition processes. The depth profiles of carbon at the tungsten surface were measured. We found that carbon distribution profiles in tungsten depend on the C redeposition rate for fixed ion irradiation parameters. Three regimes have been distinguished: (i) at working gas pressure equal to 5 Pa and more, the C redeposition rate prevails the sample surface erosion rate and the W surface is covered by continuous amorphous carbon film (the C film growth regime), (ii) at working gas pressure equal to about 1 Pa, the C redepostion rate is approximately equal to the erosion rate and the W surface is partially covered by redeposited carbon, and (iii) at working gas pressure less than 0.2 Pa, the erosion rate prevails the C redeposition rate (the W surface erosion regime). In the regime of balanced redeposition and erosion deep C penetration depth into nanocrystalline W was registered. It is suggested that under simultaneous C adsorption and ion irradiation at elevated temperature C adatoms are driven from the W surface into grain boundaries and into the bulk by the difference in chemical potentials between the activated W surface and grain boundaries. As the W surface is covered by amorphous C film, the grain boundaries are blocked and the efficiency of carbon transport decreases

  16. Study on the irradiation port for wide spread use of carbon cancer therapy

    International Nuclear Information System (INIS)

    Komori, Masataka; Yonai, Shunsuke; Kanai, Tatsuaki

    2006-01-01

    A compact irradiation port for wide spread use of carbon radiotherapy is designed. The port length will be reduced to 5.5 m, which equal to half-length of Heavy Ion Medical Accelerator in Chiba (HIMAC). The broad beam method will be used to produce an irradiation field up to 220 mm in diameter and 250 mm in depth. We propose an amplitude-modulation wobbler method, so called spiral wobbler method, to produce the large irradiation field using a small radius beam. The system has an advantage that the residual range at an iso-center is longer than that produced by a conventional wobbler-scatterer method. An accurate dose estimation system will be introduced instead of measuring a calibration factor of dose monitor for each patient. In this project, we verify the design of the irradiation port and the dose estimation system. (author)

  17. Effects of carbonation, irradiation and temperature onto strontium immobilization into a cementitious matrix

    International Nuclear Information System (INIS)

    Bar-Nes, G.; Arbel-Haddad, M.; Chomat, L.; Poyet, S.; Mace, N.; Hossepied, C.

    2015-01-01

    In the present study, the decoupled effects of carbonation, irradiation and temperature on strontium immobilization in a CEM-I cement matrix are described. After 6 months of treatment, mineralogical characterization (X-ray diffraction - XRD and thermogravimetric analysis - TGA), leaching tests (according to ANSI.ANS-16.1 standard method) and sorption experiments were carried out. The mineralogical evolution was shown to be similar for samples submitted to irradiation at atmospheric conditions or carbonation at a controlled temperature of 40 C. degrees. The main mineralogical change during these two treatments is the formation of calcium carbonate; calcite is detected at the sample surface and the two carbonate metastable phases (aragonite and vaterite) in the depth of the sample. Although it was not possible to identify, by the techniques used, the association of Sr with any specific cementitious phase present in the investigated samples, the leaching results showed that the fraction of Sr leached from samples exposed to carbonation during their degradation process, was approximately 6 times lower compared to the corresponding samples degraded under inert conditions. The sorption experiments onto the hydrated cement paste show a small but significant retention of Sr in these matrices without allowing a possible identification of the phase responsible for the retention. Post leaching mineralogical characterization is to be performed in order to study the effect of the leaching process on the sample mineralogy and to locate the binding sites of the Sr ions within the cementitious paste. (authors)

  18. Gasification of carbon deposits on catalysts and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, J L

    1986-10-01

    'Coke' deposited on catalysts and reactor surfaces includes a variety of carbons of different structures and origins, their reactivities being conveniently assessed by Temperature Programmed Reaction (TPR). The gasification of carbon deposits obtained in the laboratory under well controlled conditions, and the regeneration of coked catalysts from petroleum refining processes are reviewed and discussed. Filamentary carbon deposits, containing dispersed metal particles, behave as supported metal catalysts during gasification, and show high reactivities. Pyrolytic and acid catalysis carbons are less reactive on their own, as the gasification is not catalysed; however, metal components of the catalyst or metal impurities deposited on the surface may enhance gasification. 26 refs., 8 figs., 2 tabs.

  19. Regeneration of carbon nanotubes exhausted with dye reactive red 3BS using microwave irradiation

    International Nuclear Information System (INIS)

    Wang Jun; Peng Xianjia; Luan Zhaokun; Zhao Changwei

    2010-01-01

    Carbon nanotubes (CNTs) exhausted with dye reactive red 3BS were regenerated by microwave irradiation under N 2 atmosphere. High regeneration efficiency was achieved and the regeneration efficiency reached 92.8% after four cycles regeneration. The decrease in adsorption capacity was suggested to be due to the deposition of decomposition residues in CNT pores, which blocked the carbon porosity and decreased the specific surface area.

  20. Radiation damage in carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eartherly, W.P.; Nelson, G.E.

    1992-01-01

    Graphite and carbon-carbon composite materials are widely used in plasma facing applications in current Tokamak devices such as TFTR and DIIID in the USA, JET, Tore Supra and TEXTOR in Europe, and JT-60U in Japan. Carbon-carbon composites are attractive choices for Tokamak limiters and diverters because of their low atomic number, high thermal shock resistance, high melting point, and high thermal conductivity. Next generation machines such as the International Thermonuclear Experimental Reactor (ITER) will utilize carbon-carbon composites in their first wall and diverter. ITER will be an ignition machine and thus will produce substantial neutron fluences from the D-T fusion reaction. The resultant high energy neutrons will cause carbon atom displacements in the plasma facing materials which will markedly affect their structure and physical properties. The effect of neutron damage on graphite has been studied for over forty years. Recently the effects of neutron irradiation on the fusion relevant graphite GraphNOL N3M was reviewed. In contrast to graphite, relatively little work has been performed to elucidate the effects of neutron irradiation on carbon-carbon composites. The results of our previous irradiation experiments have been published elsewhere. Here the irradiation induced dimensional changes in 1D, 2D, and 3D carbon-carbon composites are reported for fluences up to 4.7 dpa at an irradiation temperature of 600 degree C

  1. Carbon in high-purity germanium

    International Nuclear Information System (INIS)

    Haller, E.E.; Hansen, W.L.; Luke, P.; McMurray, R.; Jarrett, B.

    1981-10-01

    Using 14 C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon content and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internally decaying 14 C nuclei with close to 100% efficiency. An average value for the total carbon concentration [ 14 C + 12 C] is approx. 2 x 10 14 cm -3 , a value substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to agree very well with the statistical shape predicted for allowed transitions

  2. Strain-dependent Damage in Mouse Lung After Carbon Ion Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Moritake, Takashi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Proton Medical Research Center, University of Tsukuba, Tsukuba (Japan); Fujita, Hidetoshi; Yanagisawa, Mitsuru; Nakawatari, Miyako; Imadome, Kaori; Nakamura, Etsuko; Iwakawa, Mayumi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Imai, Takashi, E-mail: imait@nirs.go.jp [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)

    2012-09-01

    Purpose: To examine whether inherent factors produce differences in lung morbidity in response to carbon ion (C-ion) irradiation, and to identify the molecules that have a key role in strain-dependent adverse effects in the lung. Methods and Materials: Three strains of female mice (C3H/He Slc, C57BL/6J Jms Slc, and A/J Jms Slc) were locally irradiated in the thorax with either C-ion beams (290 MeV/n, in 6 cm spread-out Bragg peak) or with {sup 137}Cs {gamma}-rays as a reference beam. We performed survival assays and histologic examination of the lung with hematoxylin-eosin and Masson's trichrome staining. In addition, we performed immunohistochemical staining for hyaluronic acid (HA), CD44, and Mac3 and assayed for gene expression. Results: The survival data in mice showed a between-strain variance after C-ion irradiation with 10 Gy. The median survival time of C3H/He was significantly shortened after C-ion irradiation at the higher dose of 12.5 Gy. Histologic examination revealed early-phase hemorrhagic pneumonitis in C3H/He and late-phase focal fibrotic lesions in C57BL/6J after C-ion irradiation with 10 Gy. Pleural effusion was apparent in C57BL/6J and A/J mice, 168 days after C-ion irradiation with 10 Gy. Microarray analysis of irradiated lung tissue in the three mouse strains identified differential expression changes in growth differentiation factor 15 (Gdf15), which regulates macrophage function, and hyaluronan synthase 1 (Has1), which plays a role in HA metabolism. Immunohistochemistry showed that the number of CD44-positive cells, a surrogate marker for HA accumulation, and Mac3-positive cells, a marker for macrophage infiltration in irradiated lung, varied significantly among the three mouse strains during the early phase. Conclusions: This study demonstrated a strain-dependent differential response in mice to C-ion thoracic irradiation. Our findings identified candidate molecules that could be implicated in the between-strain variance to early

  3. Multi-walled carbon nanotube structural instability with/without metal nanoparticles under electron beam irradiation

    Science.gov (United States)

    Khan, Imran; Huang, Shengli; Wu, Chenxu

    2017-12-01

    The structural transformation of multi-walled carbon nanotubes (MWCNT) under electron beam (e-beam) irradiation at room temperature is studied, with respect to a novel passivation effect due to gold nanoparticles (Au NPs). MWCNT structural evolution induced by energetic e-beam irradiation leads to faster shrinkage, as revealed via in situ transmission electron microscopy, while MWCNT surface modification with Au NPs (Au-MWCNT) slows down the shrinkage by impeding the structural evolution process for a prolonged time under the same irradiation conditions. The new relationship between MWCNT and Au-MWCNT shrinking radii and irradiation time illustrates that the MWCNT shrinkage rate is faster than either theoretical predictions or the same process in Au-MWCNTs. As compared with the outer surface energy (positive curvature), the inner surface energy (negative curvature) of the MWCNT contributes more to the athermal evaporation of tube wall atoms, leading to structural instability and shrinkage under e-beam irradiation. Conversely, Au NPs possess only outer surface energy (positive curvature) compared with the MWCNT. Their presence on MWCNT surfaces retards the dynamics of MWCNT structural evolution by slowing down the evaporation process of carbon atoms, thus restricting Au-MWCNT shrinkage. Au NP interaction and growth evolves athermally on MWCNT surfaces, exhibits increase in their size, and indicates the association of this mechanism with the coalescence induced by e-beam activated electronic excitations. Despite their growth, Au NPs show extreme structural stability, and remain crystalline under prolonged irradiation. It is proposed that the surface energy of MWCNTs and Au NPs, together with e-beam activated soft modes or lattice instability effects, predominantly govern all the above varieties of structural evolution.

  4. Radiation damage in carbon-carbon composites: Structure and property effects

    International Nuclear Information System (INIS)

    Burchell, T.D.

    1995-01-01

    Carbon-carbon composites are an attractive choice for fusion reactor plasma facing components because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation tokamak reactors such as the International Thermonuclear Experimental Reactor (ITER), will require high thermal conductivity carbon-carbon composites and other materials, such as beryllium, to protect their plasma facing components from the anticipated high heat fluxes. Moreover, ignition machines such as ITER will produce a large neutron flux. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from two irradiation experiments are reported and discussed here. Carbon-carbon composite materials were irradiated in target capsules in the High Flux Isotope Reactor (HAIR) at Oak Ridge National Laboratory (ORAL). A peak damage dose of 4.7 displacements per atom (da) at an irradiation temperature of ∼600 degrees C was attained. The carbon materials irradiated here included unidirectional, two- directional, and three-directional carbon-carbon composites. Irradiation induced dimensional changes are reported for the materials and related to single crystal dimensional changes through fiber and composite structural models. Moreover, carbon-carbon composite material dimensional changes are discussed in terms of their architecture, fiber type, and graphitization temperature. Neutron irradiation induced reductions in the thermal conductivity of two, three-directional carbon-carbon composites are reported, and the recovery of thermal conductivity due to thermal annealing is demonstrated. Irradiation induced strength changes are reported for several carbon-carbon composite materials and are explained in terms of in-crystal and composite structural effects

  5. Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties and lower carbon footprint.

    Science.gov (United States)

    Schaefer, Carolyn E; Kupwade-Patil, Kunal; Ortega, Michael; Soriano, Carmen; Büyüköztürk, Oral; White, Anne E; Short, Michael P

    2018-01-01

    Concrete production contributes heavily to greenhouse gas emissions, thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when cement is partially replaced with another material, such as waste plastic, though normally with a tradeoff in compressive strength. This study discusses progress toward a high/medium strength concrete with a dense, cementitious matrix that contains an irradiated plastic additive, recovering the compressive strength while displacing concrete with waste materials to reduce greenhouse gas generation. Compressive strength tests showed that the addition of high dose (100kGy) irradiated plastic in multiple concretes resulted in increased compressive strength as compared to samples containing regular, non-irradiated plastic. This suggests that irradiating plastic at a high dose is a viable potential solution for regaining some of the strength that is lost when plastic is added to cement paste. X-ray Diffraction (XRD), Backscattered Electron Microscopy (BSE), and X-ray microtomography explain the mechanisms for strength retention when using irradiated plastic as a filler for cement paste. By partially replacing Portland cement with a recycled waste plastic, this design may have a potential to contribute to reduced carbon emissions when scaled to the level of mass concrete production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Electron-impact and pyrolytic eliminations from 4-tert-butylcyclohexyl xanthates

    International Nuclear Information System (INIS)

    Eadon, G.; Jefson, M.

    1976-01-01

    The stereochemistry of electron--impact induced xanthic acid elimination reactions was assessed by mass spectrographic studies of cis and trans deuterated 4-tert-butylcyclohexyl xanthates and their derivatives. Cis elimination was observed to be about 30 times as facile as trans elimination in the axial xanthate reaction. In the equatorial ester derivative reactions, the cis elimination was found to be slightly preferred. The electron-impact induced elimination results were compared with pyrolytic elimination results for the xanthates; and similar stereochemistry was observed for each type of elimination

  7. Carbon ion irradiation of the human prostate cancer cell line PC3: A whole genome microarray study

    Science.gov (United States)

    SUETENS, ANNELIES; MOREELS, MARJAN; QUINTENS, ROEL; CHIRIOTTI, SABINA; TABURY, KEVIN; MICHAUX, ARLETTE; GRÉGOIRE, VINCENT; BAATOUT, SARAH

    2014-01-01

    Hadrontherapy is a form of external radiation therapy, which uses beams of charged particles such as carbon ions. Compared to conventional radiotherapy with photons, the main advantage of carbon ion therapy is the precise dose localization along with an increased biological effectiveness. The first results obtained from prostate cancer patients treated with carbon ion therapy showed good local tumor control and survival rates. In view of this advanced treatment modality we investigated the effects of irradiation with different beam qualities on gene expression changes in the PC3 prostate adenocarcinoma cell line. For this purpose, PC3 cells were irradiated with various doses (0.0, 0.5 and 2.0 Gy) of carbon ions (LET=33.7 keV/μm) at the beam of the Grand Accélérateur National d’Ions Lourds (Caen, France). Comparative experiments with X-rays were performed at the Belgian Nuclear Research Centre. Genome-wide gene expression was analyzed using microarrays. Our results show a downregulation in many genes involved in cell cycle and cell organization processes after 2.0 Gy irradiation. This effect was more pronounced after carbon ion irradiation compared with X-rays. Furthermore, we found a significant downregulation of many genes related to cell motility. Several of these changes were confirmed using qPCR. In addition, recurrence-free survival analysis of prostate cancer patients based on one of these motility genes (FN1) revealed that patients with low expression levels had a prolonged recurrence-free survival time, indicating that this gene may be a potential prognostic biomarker for prostate cancer. Understanding how different radiation qualities affect the cellular behavior of prostate cancer cells is important to improve the clinical outcome of cancer radiation therapy. PMID:24504141

  8. Transplantation of ES cells to Parkinson model rat irradiated with carbon ion beam

    International Nuclear Information System (INIS)

    Inaji, Motoki; Okauchi, Takashi; Nagai, Yuji; Nojima, Kumie

    2003-01-01

    The present study was designed to make better Parkinson model animal and evaluate the transplantation treatment with ES cell. In the first year, we irradiated left striatum of adult rats with charged carbon particles (290 MeV/nucleon, 5 mm spread-out Bragg peak, 100 Gy) for purpose of making Parkinson model rats. At 4, 8, 12 weeks after the irradiation, we performed the rotation test to methamphetamine and the autoradiography on dopamine D2 receptor and transporter using 11 C-raclopride and 11 C-PE2I to measure the effects of the irradiation. As a result, the number of rotation increased and the distributions of dopamine D2 receptor and transporter in the striatum decreased during the time after the irradiation. These results suggested that the secondary neural damage due to the vascular degeneration caused the progressive destruction of dopamine system. To make more stable Parkinson model rats, we need to use smaller collimator and develop the accurate stereotactic irradiation system in the further research. (author)

  9. Three-dimensional Invasion of Human Glioblastoma Cells Remains Unchanged by X-ray and Carbon Ion Irradiation In Vitro

    Energy Technology Data Exchange (ETDEWEB)

    Eke, Iris; Storch, Katja; Kaestner, Ina; Vehlow, Anne [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Faethe, Christina; Mueller-Klieser, Wolfgang [Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz (Germany); Taucher-Scholz, Gisela [Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany); Temme, Achim; Schackert, Gabriele [Section of Experimental Neurosurgery/Tumor Immunology, Department of Neurosurgery, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Cordes, Nils, E-mail: Nils.Cordes@Oncoray.de [OncoRay-National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany); Department of Radiation Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden (Germany)

    2012-11-15

    Purpose: Cell invasion represents one of the major determinants that treatment has failed for patients suffering from glioblastoma. Contrary findings have been reported for cell migration upon exposure to ionizing radiation. Here, the migration and invasion capability of glioblastoma cells on and in collagen type I were evaluated upon irradiation with X-rays or carbon ions. Methods and Materials: Migration on and invasion in collagen type I were evaluated in four established human glioblastoma cell lines exposed to either X-rays or carbon ions. Furthermore, clonogenic radiation survival, proliferation (5-bromo-2-deoxyuridine positivity), DNA double-strand breaks ({gamma}H2AX/53BP1-positive foci), and expression of invasion-relevant proteins (eg, {beta}1 integrin, FAK, MMP2, and MMP9) were explored. Migration and invasion assays for primary glioblastoma cells also were carried out with X-ray irradiation. Results: Neither X-ray nor carbon ion irradiation affected glioblastoma cell migration and invasion, a finding similarly observed in primary glioblastoma cells. Intriguingly, irradiated cells migrated unhampered, despite DNA double-strand breaks and reduced proliferation. Clonogenic radiation survival was increased when cells had contact with extracellular matrix. Specific inhibition of the {beta}1 integrin or proliferation-associated signaling molecules revealed a critical function of JNK, PI3K, and p38 MAPK in glioblastoma cell invasion. Conclusions: These findings indicate that X-rays and carbon ion irradiation effectively reduce proliferation and clonogenic survival without modifying the migration and invasion ability of glioblastoma cells in a collagen type I environment. Addition of targeted agents against members of the MAPK and PI3K signaling axis to conventional chemoradiation therapy seems potentially useful to optimize glioblastoma therapy.

  10. Effect of high carbon dioxide storage and gamma irradiation on membrane deterioration in cauliflower florets

    International Nuclear Information System (INIS)

    Voisine, R.; Hombourger, C.; Willemot, C.; Castaigne, F.; Makhlouf, J.

    1993-01-01

    Controlled atmospheres and gamma irradiation are technologies which extend storage-life of fruits and vegetables. Separate and combined effects of high CO 2 storage and gamma irradiation on cell membranes from cauliflower florets (Brassica oleracea L., Botrytis group) were investigated. Storage of the florets for 8 days at 13°C, either under 15% carbon dioxide or in air after irradiation at 2 kGy, accelerated the deterioration of microsomal membranes during storage. Both treatments caused an early loss in lipid phosphate. Irradiation enhanced the free fatty acid content of the membranes during storage and caused an extensive protein loss. When irradiation and high CO 2 storage were combined, electrolyte leakage significantly increased while protein loss was considerably reduced. The results indicate that high CO 2 and irradiation accelerate membrane degradation through different mechanisms. The combined effects of the treatments were not additive, but membrane yield was apparently reduced. CO 2 protected the membranes from protein loss induced by irradiation. The apparent increase in electrolyte leakage after irradiation may be caused by the release of ions following cell wall deterioration

  11. Comparison of the effects of photon versus carbon ion irradiation when combined with chemotherapy in vitro

    International Nuclear Information System (INIS)

    Schlaich, Fabian; Brons, Stephan; Haberer, Thomas; Debus, Jürgen; Combs, Stephanie E; Weber, Klaus-Josef

    2013-01-01

    Characterization of combination effects of chemotherapy drugs with carbon ions in comparison to photons in vitro. The human colon adenocarcinoma cell line WiDr was tested for combinations with camptothecin, cisplatin, gemcitabine and paclitaxel. In addition three other human tumour cell lines (A549: lung, LN-229: glioblastoma, PANC-1: pancreas) were tested for the combination with camptothecin. Cells were irradiated with photon doses of 2, 4, 6 and 8 Gy or carbon ion doses of 0.5, 1, 2 and 3 Gy. Cell survival was assessed using the clonogenic growth assay. Treatment dependent changes in cell cycle distribution (up to 12 hours post-treatment) were measured by FACS analysis after propidium-iodide staining. Apoptosis was monitored for up to 36 hours post-treatment by Nicoletti-assay (with qualitative verification using DAPI staining). All cell lines exhibited the well-known increase of killing efficacy per unit dose of carbon ion exposure, with relative biological efficiencies at 10% survival (RBE 10 ) ranging from 2.3 to 3.7 for the different cell lines. In combination with chemotherapy additive toxicity was the prevailing effect. Only in combination with gemcitabine or cisplatin (WiDr) or camptothecin (all cell lines) the photon sensitivity was slightly enhanced, whereas purely independent toxicities were found with the carbon ion irradiation, in all cases. Radiation-induced cell cycle changes displayed the generally observed dose-dependent G2-arrest with little effect on S-phase fraction for all cell lines for photons and for carbon ions. Only paclitaxel showed a significant induction of apoptosis in WiDr cell line but independent of the used radiation quality. Combined effects of different chemotherapeutics with photons or with carbon ions do neither display qualitative nor substantial quantitative differences. Small radiosensitizing effects, when observed with photons are decreased with carbon ions. The data support the idea that a radiochemotherapy with common

  12. A study of point defects created by electron irradiation of dilute iron-carbon alloys

    International Nuclear Information System (INIS)

    Leveque, J.L.

    1969-10-01

    Resistivity and magnetic after effect (m.a.e.) measurements are used to study the influence of carbon atoms on the annealing process of point defects created by electron irradiation (3 MeV) at low temperature (20 deg. K). The presence of the carbon atoms has a strong influence on the recovery sub-stage I E and stage III. For the former, the carbon impurity traps the freely migrating iron interstitial. For the latter the effect is interpreted as being due to formation during annealing, of a carbon vacancy pair. A pronounced m.a.e. band is attributed to the reorientation of this carbon vacancy complex. All these results are coherent with the interpretation of a low temperature migrating free interstitial. (author) [fr

  13. Effects of carbon dioxide on pyrolysis of peat

    International Nuclear Information System (INIS)

    Lee, Jechan; Yang, Xiao; Song, Hocheol; Ok, Yong Sik; Kwon, Eilhann E.

    2017-01-01

    This study focuses on the mechanistic understanding of effects of CO 2 on pyrolysis of peat. To do this, three pyrolytic products (i.e., syngas: H 2 and CO, pyrolytic oil (tar), and biochar) were characterized. Thermal cracking of volatile organic carbons (VOCs) generated from pyrolysis of peat was enhanced in the presence of CO 2 . Besides the enhanced thermal cracking of VOCs, unknown reaction between CO 2 and VOCs was also identified. Accordingly, CO 2 played a role in enhancing syngas production and in reducing tar formation in pyrolysis of peat. This study also reveals that peat-biochar produced in CO 2 exhibited a larger surface area than that produced in N 2 . The results shown in this paper would be used for various applications such as energy recovery from peat using a potent greenhouse gas (for example, CO 2 ). - Highlights: • More CO can be produced from pyrolysis of peat in CO 2 than in N 2 . • Less amount of tar produced from pyrolysis of peat in CO 2 than in N 2 . • Surface area of peat-biochar made in CO 2 is larger than that made in N 2 . • CO 2 can modify the quantity/quality of pyrolytic products from peat.

  14. Multiwalled carbon nanotube destruction in the radiation damages to electron irradiation

    Directory of Open Access Journals (Sweden)

    T. M. Pinchuk-Rugal’

    2015-10-01

    Full Text Available Behavior of the X-ray diffraction and vibrational Raman spectra of multiwalled carbon nanotubes (MWCNT under high-energy electron irradiation (Ee = 1.8 MeV with large doses of absorption to 10 MGy were studied. With increasing dose uptake to 10.0 MGy, the interlayer correlation in the distribution of the individual graphene nanotubes nets not only is maintained, but is even improved. Defective bands D, D' and G band with increasing dose absorption have significant transformation, which show radiation damages of MWCNT. The destruction of nanotubes under electron irradiation is accompanied by increased regulation in the arrangement of individual nanotubes by interlayer cross-links involving interstitial atoms. The severity of degradation and cross-linking of MWCNT depends on the electron absorption dose.

  15. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation.

    Science.gov (United States)

    Polf, Jerimy C; Panthi, Rajesh; Mackin, Dennis S; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T; Beddar, Sam

    2013-09-07

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from (12)C (4.44 MeV) and (16)O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 10(7) oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from (16)O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring (16)O PG emission.

  16. Ultraviolet pulsed laser irradiation of multi-walled carbon nanotubes in nitrogen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pérez del Pino, Ángel, E-mail: aperez@icmab.es; Cabana, Laura; Tobias, Gerard [Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra (Spain); György, Enikö [Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra (Spain); National Institute for Lasers, Plasma and Radiation Physics, P. O. Box MG 36, 76900 Bucharest V (Romania); Ballesteros, Belén [ICN2—Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2014-03-07

    Laser irradiation of randomly oriented multi-walled carbon nanotube (MWCNT) networks has been carried out using a pulsed Nd:YAG UV laser in nitrogen gas environment. The evolution of the MWCNT morphology and structure as a function of laser fluence and number of accumulated laser pulses has been studied using electron microscopies and Raman spectroscopy. The observed changes are discussed and correlated with thermal simulations. The obtained results indicate that laser irradiation induces very fast, high temperature thermal cycles in MWCNTs which produce the formation of different nanocarbon forms, such as nanodiamonds. Premelting processes have been observed in localized sites by irradiation at low number of laser pulses and low fluence values. The accumulation of laser pulses and the increase in the fluence cause the full melting and amorphization of MWCNTs. The observed structural changes differ from that of conventional high temperature annealing treatments of MWCNTs.

  17. Nano-Welding of Multi-Walled Carbon Nanotubes on Silicon and Silica Surface by Laser Irradiation

    Directory of Open Access Journals (Sweden)

    Yanping Yuan

    2016-02-01

    Full Text Available In this study, a continuous fiber laser (1064 nm wavelength, 30 W/cm2 is used to irradiate multi-walled carbon nanotubes (MWCNTs on different substrate surfaces. Effects of substrates on nano-welding of MWCNTs are investigated by scanning electron microscope (SEM. For MWCNTs on silica, after 3 s irradiation, nanoscale welding with good quality can be achieved due to breaking C–C bonds and formation of new graphene layers. While welding junctions can be formed until 10 s for the MWCNTs on silicon, the difference of irradiation time to achieve welding is attributed to the difference of thermal conductivity for silica and silicon. As the irradiation time is prolonged up to 12.5 s, most of the MWCNTs are welded to a silicon substrate, which leads to their frameworks of tube walls on the silicon surface. This is because the accumulation of absorbed energy makes the temperature rise. Then chemical reactions among silicon, carbon and nitrogen occur. New chemical bonds of Si–N and Si–C achieve the welding between the MWCNTs and silicon. Vibration modes of Si3N4 appear at peaks of 363 cm−1 and 663 cm−1. There are vibration modes of SiC at peaks of 618 cm−1, 779 cm−1 and 973 cm−1. The experimental observation proves chemical reactions and the formation of Si3N4 and SiC by laser irradiation.

  18. Nano-Welding of Multi-Walled Carbon Nanotubes on Silicon and Silica Surface by Laser Irradiation

    Science.gov (United States)

    Yuan, Yanping; Chen, Jimin

    2016-01-01

    In this study, a continuous fiber laser (1064 nm wavelength, 30 W/cm2) is used to irradiate multi-walled carbon nanotubes (MWCNTs) on different substrate surfaces. Effects of substrates on nano-welding of MWCNTs are investigated by scanning electron microscope (SEM). For MWCNTs on silica, after 3 s irradiation, nanoscale welding with good quality can be achieved due to breaking C–C bonds and formation of new graphene layers. While welding junctions can be formed until 10 s for the MWCNTs on silicon, the difference of irradiation time to achieve welding is attributed to the difference of thermal conductivity for silica and silicon. As the irradiation time is prolonged up to 12.5 s, most of the MWCNTs are welded to a silicon substrate, which leads to their frameworks of tube walls on the silicon surface. This is because the accumulation of absorbed energy makes the temperature rise. Then chemical reactions among silicon, carbon and nitrogen occur. New chemical bonds of Si–N and Si–C achieve the welding between the MWCNTs and silicon. Vibration modes of Si3N4 appear at peaks of 363 cm−1 and 663 cm−1. There are vibration modes of SiC at peaks of 618 cm−1, 779 cm−1 and 973 cm−1. The experimental observation proves chemical reactions and the formation of Si3N4 and SiC by laser irradiation. PMID:28344293

  19. Object kinetic Monte Carlo model for neutron and ion irradiation in tungsten: Impact of transmutation and carbon impurities

    Science.gov (United States)

    Castin, N.; Bonny, G.; Bakaev, A.; Ortiz, C. J.; Sand, A. E.; Terentyev, D.

    2018-03-01

    We upgrade our object kinetic Monte Carlo (OKMC) model, aimed at describing the microstructural evolution in tungsten (W) under neutron and ion irradiation. Two main improvements are proposed based on recently published atomistic data: (a) interstitial carbon impurities, and their interaction with radiation-induced defects (point defect clusters and loops), are more accurately parameterized thanks to ab initio findings; (b) W transmutation to rhenium (Re) upon neutron irradiation, impacting the diffusivity of radiation defects, is included, also relying on recent atomistic data. These essential amendments highly improve the portability of our OKMC model, providing a description for the formation of SIA-type loops under different irradiation conditions. The model is applied to simulate neutron and ion irradiation in pure W samples, in a wide range of fluxes and temperatures. We demonstrate that it performs a realistic prediction of the population of TEM-visible voids and loops, as compared to experimental evidence. The impact of the transmutation of W to Re, and of carbon trapping, is assessed.

  20. Influence of oxygen, nitrogen and carbonic gas during gamma irradiation of 'Sitophilus zeamais' Mots. and 'Zabrotes subfasciatus' (Boh.)

    International Nuclear Information System (INIS)

    Wiendl, F.M.; Tornisielo, V.L.; Walder, J.M.N.; Sgrillo, R.B.

    1976-01-01

    Zero to twenty-four hour old adults of the corn-weevil (S. zeamais) and of the bean weevil (Z. subfasciatus) with their food were irradiated with 5 krad of gamma rays from a Co-60 source (dose rate of 96.25 krad/h). The foodstuffs for the corn weevil were maize and rice as well as common beans for the bean weevil. Before irradiation, the insects of each treatment were exposed to 30 minutes gas fluxes of air, oxygen, nitrogen or carbonic gas, respectively. After irradiation, insects were kept in a temperature controlled chamber at 28 0 C. Losses in weight of the foodstuffs were recorded for 51 weeks. The greatest weight loss was found in the treatment with air flux. Weight losses decreased with the nitrogen, carbonic gas and oxygen treatments, respectively [pt

  1. Comparative study of neutron irradiation and carbon doping in MgB2 single crystals

    International Nuclear Information System (INIS)

    Krutzler, C.; Zehetmayer, M.; Eisterer, M.; Weber, H. W.; Zhigadlo, N. D.; Karpinski, J.

    2007-01-01

    We compare the reversible and irreversible magnetic properties of superconducting carbon doped and undoped MgB 2 single crystals before and after neutron irradiation. A large number of samples with transition temperatures between 38.3 and 22.8 K allows us to study the effects of disorder systematically. Striking similarities are found in the modification of the reversible parameters by irradiation and doping, which are discussed in terms of impurity scattering and changes of the Fermi surface. The irreversible properties are influenced by two counteracting mechanisms: they are enhanced by the newly introduced pinning centers but degraded by changes in the thermodynamic properties. Accordingly, the large neutron induced defects and the small defects from carbon doping lead to significantly different effects on the irreversible properties. Finally, the fishtail effect caused by all kinds of disorder is discussed in terms of an order-disorder transition of the flux-line lattice

  2. X-ray photoelectron spectroscopy study of pyrolytically coated graphite platforms submitted to simulated electrothermal atomic absorption spectrometry conditions

    International Nuclear Information System (INIS)

    Ruiz, Frine; Benzo, Zully; Quintal, Manuelita; Garaboto, Angel; Albornoz, Alberto; Brito, Joaquin L.

    2006-01-01

    The present work is part of an ongoing project aiming to a better understanding of the mechanisms of atomization on graphite furnace platforms used for electrothermal atomic absorption spectrometry (ETAAS). It reports the study of unused pyrolytic graphite coated platforms of commercial origin, as well as platforms thermally or thermo-chemically treated under simulated ETAAS analysis conditions. X-ray photoelectron spectroscopy (XPS) was employed to study the elements present at the surfaces of the platforms. New, unused platforms showed the presence of molybdenum, of unknown origin, in concentrations up to 1 at.%. Species in two different oxidations states (Mo 6+ and Mo 2+ ) were detected by analyzing the Mo 3d spectral region with high resolution XPS. The analysis of the C 1s region demonstrated the presence of several signals, one of these at 283.3 eV related to the presence of Mo carbide. The O 1s region showed also various peaks, including a signal that can be attributed to the presence of MoO 3 . Some carbon and oxygen signals were consistent with the presence of C=O and C-O- (probably C-OH) groups on the platforms surfaces. Upon thermal treatment up to 2900 deg. C, the intensity of the Mo signal decreased, but peaks due to Mo oxides (Mo 6+ and Mo 5+ ) and carbide (Mo 2+ ) were still apparent. Thermo-chemical treatment with 3 vol.% HCl solutions and heating up to 2900 deg. C resulted in further diminution of the Mo signal, with complete disappearance of Mo carbide species. Depth profiling of unused platforms by Ar + ion etching at increasing time periods demonstrated that, upon removal of several layers of carbonaceous material, the Mo signal disappears suggesting that this contamination is present only at the surface of the pyrolytic graphite platform

  3. Annealing effects of carbon fiber-reinforced epoxy resin composites irradiated by electron beams

    International Nuclear Information System (INIS)

    Udagawa, Akira; Sasuga, Tuneo; Ito, Hiroshi; Hagiwara, Miyuki

    1987-01-01

    Carbon cloth-reinforced epoxy resin composites were irradiated with 2 MeV electrons at room temperature and then annealed in air for 2 h at temperatures up to 180 deg C. A considerable decrease in the three-point bending strength occurred when the irradiated composites were annealed in the temperature range of 115 - 135 deg C which is below the glass transition temperature T g of the matrix resin, while the bending strength remained unchanged up to 180 deg C for the unirradiated composites. In the dynamic viscoelastic spectra of the irradiated matrix, a new relaxation appeared at the temperature extending from 50 deg C to just below the matrix T g and disappeared on annealing for 2 h at 135 deg C. Annealing also decreased the concentration of free radicals existing stably in the irradiated matrix at room temperature. After annealing, a large amount of clacks and voids were observed in the fractography of the composites by scanning electron microscopy. These results indicate: (1) Annealing brings about rearrangement of the radiation-induced molecular chain scission in the matrix; (2) The bending strength of the irradiated composites decreased owing to the increased brittleness of the matrix by annealing. (author)

  4. Graphite irradiated by swift heavy ions under grazing incidence

    CERN Document Server

    Liu, J; Müller, C; Neumann, R

    2002-01-01

    Highly oriented pyrolytic graphite is irradiated with various heavy projectiles (Ne, Ni, Zn, Xe and U) in the MeV to GeV energy range under different oblique angles of incidence. Using scanning tunneling microscopy, the impact zones are imaged as hillocks protruding from the surface. The diameter of surface-grazing tracks varies between 3 nm (Ne) and 6 nm (U), which is about twice as large as under normal beam incidence. Exclusively for U and Xe projectiles, grazing tracks exhibit long comet-like tails consisting of successive little bumps indicating that the damage along the ion path is discontinuous even for highest electronic stopping powers.

  5. Carbon-centered radicals in γ-irradiated bone substituting biomaterials based on hydroxyapatite.

    Science.gov (United States)

    Sadlo, Jaroslaw; Strzelczak, Grazyna; Lewandowska-Szumiel, Malgorzata; Sterniczuk, Marcin; Pajchel, Lukasz; Michalik, Jacek

    2012-09-01

    Gamma irradiated synthetic hydroxyapatite, bone substituting materials NanoBone(®) and HA Biocer were examined using EPR spectroscopy and compared with powdered human compact bone. In every case, radiation-induced carbon centered radicals were recorded, but their molecular structures and concentrations differed. In compact bone and synthetic hydroxyapatite the main signal assigned to the CO(2) (-) anion radical was stable, whereas the signal due to the CO(3) (3-) radical dominated in NanoBone(®) and HA Biocer just after irradiation. However, after a few days of storage of these samples, also a CO(2) (-) signal was recorded. The EPR study of irradiated compact bone and the synthetic graft materials suggest that their microscopic structures are different. In FT-IR spectra of NanoBone(®), HA Biocer and synthetic hydroxyapatite the HPO(4) (2-) and CO(3) (2-) in B-site groups are detected, whereas in compact bone signals due to collagen dominate.

  6. Reduction of short wavelength reflectance of multi-wall carbon nanotubes through ultraviolet laser irradiation

    Science.gov (United States)

    Stephens, Michelle S.; Simonds, Brian J.; Yung, Christopher S.; Conklin, Davis; Livigni, David J.; Oliva, Alberto Remesal; Lehman, John H.

    2018-05-01

    Multi-wall carbon nanotube coatings are used as broadband, low-reflectance absorbers for bolometric applications and for stray light control. They are also used as high emittance blackbody radiators. Irradiation of single wall carbon nanotubes with ultraviolet (UV) laser light has been shown to remove amorphous carbon debris, but there have been few investigations of the interaction of UV light with the more complex physics of multi-wall carbon nanotubes. We present measurements of reflectance and surface morphology before and after exposure of multi-wall carbon nanotube coatings to 248 nm UV laser light. We show that UV exposure reduces the reflectivity at wavelengths below 600 nm and present modeling of the thermal cycling the UV exposure causes at the surface of the carbon nanotubes. This effect can be used to flatten the spectral shape of the reflectivity curve of carbon nanotube absorber coatings used for broadband applications. Finally, we find that the effect of UV exposure depends on the nanotube growth process.

  7. Synergistic methane formation on pyrolytic graphite due to combined H+ ion and H0 atom impact

    International Nuclear Information System (INIS)

    Haasz, A.A.; Davis, J.W.; Auciello, O.; Strangeby, P.C.; Vietzke, E.; Flaskamp, K.; Philipps, V.

    1986-06-01

    Exposure of graphite to multispecies hydrogenic impact, as is the case in tokamaks, could lead to synergistic mechanisms resulting in an enhancement of methane formation, and consequently in increased carbon erosion. We present results obtained in controlled experiments in our laboratories in Toronto and Juelich for the synergistic methane production due to combined sub-eV H 0 atoms and energetic H + ion impact on pyrolytic graphite. Flux densities were 10 14 -2x10 16 H 0 /cm 2 s for the sub-eV H 0 atoms and 6x10 12 -5x10 15 H + /cm 2 for H + ions of 300 eV to 2.5 keV energy. Synergistic factors (defined as the ratio of methane formation rate due to combined H 0 and H + fluxes to the sum of the formation rates due to separate species impact) ranged from about 1.5-15 for the experimental parameters used. In addition, a spectrum of formed hydrocarbons in the synergistic reaction of H + and H 0 on graphite is presented

  8. Measurements of near-ultimate strength for multiwalled carbon nanotubes and irradiation-induced crosslinking improvements.

    Science.gov (United States)

    Peng, Bei; Locascio, Mark; Zapol, Peter; Li, Shuyou; Mielke, Steven L; Schatz, George C; Espinosa, Horacio D

    2008-10-01

    The excellent mechanical properties of carbon nanotubes are being exploited in a growing number of applications from ballistic armour to nanoelectronics. However, measurements of these properties have not achieved the values predicted by theory due to a combination of artifacts introduced during sample preparation and inadequate measurements. Here we report multiwalled carbon nanotubes with a mean fracture strength >100 GPa, which exceeds earlier observations by a factor of approximately three. These results are in excellent agreement with quantum-mechanical estimates for nanotubes containing only an occasional vacancy defect, and are approximately 80% of the values expected for defect-free tubes. This performance is made possible by omitting chemical treatments from the sample preparation process, thus avoiding the formation of defects. High-resolution imaging was used to directly determine the number of fractured shells and the chirality of the outer shell. Electron irradiation at 200 keV for 10, 100 and 1,800 s led to improvements in the maximum sustainable loads by factors of 2.4, 7.9 and 11.6 compared with non-irradiated samples of similar diameter. This effect is attributed to crosslinking between the shells. Computer simulations also illustrate the effects of various irradiation-induced crosslinking defects on load sharing between the shells.

  9. Measurements of near-ultimate strength for multiwalled carbon nanotubes and irradiation-induced crosslinking improvements.

    Energy Technology Data Exchange (ETDEWEB)

    Peng, B.; Locascio, M.; Zapol, P.; Li, S.; Mielke, S. L.; Schatz, G. C.; Espinosa, H. D.; Northwestern Univ.

    2008-01-01

    The excellent mechanical properties of carbon nanotubes are being exploited in a growing number of applications from ballistic armour to nanoelectronics. However, measurements of these properties have not achieved the values predicted by theory due to a combination of artifacts introduced during sample preparation and inadequate measurements. Here we report multiwalled carbon nanotubes with a mean fracture strength >100 GPa, which exceeds earlier observations by a factor of approximately three. These results are in excellent agreement with quantum-mechanical estimates for nanotubes containing only an occasional vacancy defect, and are {approx}80% of the values expected for defect-free tubes. This performance is made possible by omitting chemical treatments from the sample preparation process, thus avoiding the formation of defects. High-resolution imaging was used to directly determine the number of fractured shells and the chirality of the outer shell. Electron irradiation at 200 keV for 10, 100 and 1,800 s led to improvements in the maximum sustainable loads by factors of 2.4, 7.9 and 11.6 compared with non-irradiated samples of similar diameter. This effect is attributed to crosslinking between the shells. Computer simulations also illustrate the effects of various irradiation-induced crosslinking defects on load sharing between the shells.

  10. Measurements of near-ultimate strength for multiwalled carbon nanotubes and irradiation-induced crosslinking improvements

    International Nuclear Information System (INIS)

    Peng, B.; Locascio, M.; Zapol, P.; Li, S.; Mielke, S.L.; Schatz, G.C.; Espinosa, H.D.

    2008-01-01

    The excellent mechanical properties of carbon nanotubes are being exploited in a growing number of applications from ballistic armour to nanoelectronics. However, measurements of these properties have not achieved the values predicted by theory due to a combination of artifacts introduced during sample preparation and inadequate measurements. Here we report multiwalled carbon nanotubes with a mean fracture strength >100 GPa, which exceeds earlier observations by a factor of approximately three. These results are in excellent agreement with quantum-mechanical estimates for nanotubes containing only an occasional vacancy defect, and are ∼80% of the values expected for defect-free tubes. This performance is made possible by omitting chemical treatments from the sample preparation process, thus avoiding the formation of defects. High-resolution imaging was used to directly determine the number of fractured shells and the chirality of the outer shell. Electron irradiation at 200 keV for 10, 100 and 1,800 s led to improvements in the maximum sustainable loads by factors of 2.4, 7.9 and 11.6 compared with non-irradiated samples of similar diameter. This effect is attributed to crosslinking between the shells. Computer simulations also illustrate the effects of various irradiation-induced crosslinking defects on load sharing between the shells.

  11. Spectroscopic and thermal characterization of carbon nanotubes functionalized through diazonium salt reduction

    International Nuclear Information System (INIS)

    Pandurangappa, Malingappa; Ramakrishnappa, Thippeswamy

    2010-01-01

    Chemical reduction of anthraquinone diazonium chloride (Fast Red AL salt) in presence of hypophosphorous acid and carbon nanotubes results in anthraquinonyl functionalized carbon nanotubes. The surface functionalized moieties have been examined electrochemically by immobilizing them onto the surface of basal plane pyrolytic graphite electrode and studying its voltammetric behaviour. The effect of pH, and scan rate has revealed that the modified species are confined on the electrode surface. The spectroscopic characterization of the modified single walled carbon nanotubes using Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy, thermogravimetric analysis and transmission electron microscopy have revealed that the modifier molecules are covalently bonded on the surface of carbon nanotubes.

  12. Spectroscopic and thermal characterization of carbon nanotubes functionalized through diazonium salt reduction

    Energy Technology Data Exchange (ETDEWEB)

    Pandurangappa, Malingappa, E-mail: mprangachem@gmail.com [Department of Chemistry, Bangalore University, Central College Campus, Dr Ambedkar Veedhi, Bangalore 560 001 (India); Ramakrishnappa, Thippeswamy [Department of Chemistry, Bangalore University, Central College Campus, Dr Ambedkar Veedhi, Bangalore 560 001 (India)

    2010-08-01

    Chemical reduction of anthraquinone diazonium chloride (Fast Red AL salt) in presence of hypophosphorous acid and carbon nanotubes results in anthraquinonyl functionalized carbon nanotubes. The surface functionalized moieties have been examined electrochemically by immobilizing them onto the surface of basal plane pyrolytic graphite electrode and studying its voltammetric behaviour. The effect of pH, and scan rate has revealed that the modified species are confined on the electrode surface. The spectroscopic characterization of the modified single walled carbon nanotubes using Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy, thermogravimetric analysis and transmission electron microscopy have revealed that the modifier molecules are covalently bonded on the surface of carbon nanotubes.

  13. Pulsed TEA CO2 Laser Irradiation of Titanium in Nitrogen and Carbon Dioxide Gases

    Science.gov (United States)

    Ciganovic, J.; Matavulj, P.; Trtica, M.; Stasic, J.; Savovic, J.; Zivkovic, S.; Momcilovic, M.

    2017-12-01

    Surface changes created by interaction of transversely excited atmospheric carbon dioxide (TEA CO2) laser with titanium target/implant in nitrogen and carbon dioxide gas were studied. TEA CO2 laser operated at 10.6 μm, pulse length of 100 ns and fluence of ˜17 J/cm2 which was sufficient for inducing surface modifications. Induced changes depend on the gas used. In both gases the grain structure was produced (central irradiated zone) but its forms were diverse, (N2: irregular shape; CO2: hill-like forms). Hydrodynamic features at peripheral zone, like resolidified droplets, were recorded only in CO2 gas. Elemental analysis of the titanium target surface indicated that under a nitrogen atmosphere surface nitridation occurred. In addition, irradiation in both gases was followed by appearance of plasma in front of the target. The existence of plasma indicates relatively high temperatures created above the target surface offering a sterilizing effect.

  14. Voltammetric pH sensing using carbon electrodes: glassy carbon behaves similarly to EPPG.

    Science.gov (United States)

    Lu, Min; Compton, Richard G

    2014-09-21

    Developing and building on recent work based on a simple sensor for pH determination using unmodified edge plane pyrolytic graphite (EPPG) electrodes, we present a voltammetric method for pH determination using a bare unmodified glassy carbon (GC) electrode. By exploiting the pH sensitive nature of quinones present on carbon edge-plane like sites within the GC, we show how GC electrodes can be used to measure pH. The electro-reduction of surface quinone groups on the glassy carbon electrode was characterised using cyclic voltammetry (CV) and optimised with square-wave voltammetry (SWV) at 298 K and 310 K. At both temperatures, a linear correlation was observed, corresponding to a 2 electron, 2 proton Nernstian response over the aqueous pH range 1.0 to 13.1. As such, unmodified glassy carbon electrodes are seen to be pH dependent, and the Nernstian response suggests its facile use for pH sensing. Given the widespread use of glassy carbon electrodes in electroanalysis, the approach offers a method for the near-simultaneous measurement and monitoring of pH during such analyses.

  15. Dose Response of Alanine Detectors Irradiated with Carbon Ion Beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Jäkel, Oliver; Palmans, Hugo

    2011-01-01

    Purpose: The dose response of the alanine detector shows a dependence on particle energy and type, when irradiated with ion beams. The purpose of this study is to investigate the response behaviour of the alanine detector in clinical carbon ion beams and compare the results with model predictions......-dose curves deviate from predictions in the peak region, most pronounced at the distal edge of the peak. Conclusions: The used model and its implementation show a good overall agreement for quasi mono energetic measurements. Deviations in depth-dose measurements are mainly attributed to uncertainties...

  16. Development of a sensor for L-Dopa based on Co(DMG)(2)ClPy/multi-walled carbon nanotubes composite immobilized on basal plane pyrolytic graphite electrode.

    Science.gov (United States)

    Leite, Fernando Roberto Figueirêdo; Maroneze, Camila Marchetti; de Oliveira, Adriano Bof; dos Santos, Wallans Torres Pio; Damos, Flavio Santos; Silva Luz, Rita de Cássia

    2012-08-01

    L-Dopa is the immediate precursor of the neurotransmitter dopamine, being the most widely prescribed drug in the treatment of Parkinson's disease. A sensitive and selective method is presented for the voltammetric determination of L-Dopa in pharmaceutical formulations using a basal plane pyrolytic graphite (BPPG) electrode modified with chloro(pyridine)bis(dimethylglyoximato)cobalt(III) (Co(DMG)(2)ClPy) absorbed in a multi-walled carbon nanotube (MWCNT). Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy were used to characterize the materials. The electrocatalytical oxidation of L-Dopa using the Co(DMG)(2)ClPy/MWCNT/BPPG electrode was investigated by cyclic voltammetry and square wave voltammetry. The parameters that influence the electrode response (the amount of Co(DMG)(2)ClPy and of MWCNT, buffer solution, buffer concentration, buffer pH, frequency and potential pulse amplitude) were investigated. Voltammetric peak currents showed a linear response for L-Dopa concentration in the range of 3 to 100 μM, with a sensitivity of 4.43 μAcm(-2)/μM and a detection limit of 0.86 μM. The related standard deviation for 10 determinations of 50 μM L-Dopa was 1.6%. The results obtained for L-Dopa determination in pharmaceutical formulations (tablets) were in agreement with the compared official method. The sensor was successfully applied for L-Dopa selective determination in pharmaceutical formulations. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Catalytic hydrotreatment of pyrolytic lignins to give alkylphenolics and aromatics using a supported Ru catalyst

    NARCIS (Netherlands)

    Kloekhorst, Arjan; Wildschut, Jelle; Heeres, Hero Jan

    2014-01-01

    The catalytic hydrotreatment of two pyrolytic lignins (pine and forestry residue), obtained from the corresponding fast pyrolysis oils, and organosolv Alcell lignin as a benchmark was explored in a batch set-up using Ru/C as the catalyst (400 degrees C, 4 h, 100 bar initial H-2 pressure). The

  18. Electronic Transport and Raman Spectroscopy Characterization in Ion-Implanted Highly Oriented Pyrolytic Graphite

    Science.gov (United States)

    de Jesus, R. F.; Turatti, A. M.; Camargo, B. C.; da Silva, R. R.; Kopelevich, Y.; Behar, M.; Balzaretti, N. M.; Gusmão, M. A.; Pureur, P.

    2018-02-01

    We report on Raman spectroscopy, temperature-dependent in-plane resistivity, and in-plane magnetoresistance experiments in highly oriented pyrolytic graphite (HOPG) implanted with As and Mn. A pristine sample was also studied for comparison. Two different fluences were applied, φ = 0.5× 10^{16} {ions}/{cm}2 and φ = 1.0× 10^{16} {ions}/{cm}2. The implantations were carried out with 20 keV ion energy at room temperature. The Raman spectroscopy results reveal the occurrence of drastic changes of the HOPG surface as a consequence of the damage caused by ionic implantation. For the higher dose, the complete amorphization limit is attained. The resistivity and magnetoresistance results were obtained placing electrical contacts on the irradiated sample surface. Owing to the strong anisotropy of HOPG, the electrical current propagates mostly near the implanted surface. Shubnikov-de Haas (SdH) oscillations were observed in the magnetoresistance at low temperatures. These results allow the extraction of the fundamental SdH frequencies and the carriers' effective masses. In general, the resistivity and magnetoresistance results are consistent with those obtained from Raman measurements. However, one must consider that the electrical conduction in our samples occurs as in a parallel association of a largely resistive thin sheet at the surface strongly modified by disorder with a thicker layer where damage produced by implantation is less severe. The SdH oscillations do not hint to significant changes in the carrier density of HOPG.

  19. Response of the skin of hamsters to fractionated irradiation with X rays or accelerated carbon ions

    International Nuclear Information System (INIS)

    Leith, J.T.; Powers-Risius, P.; Woodruff, K.H.; McDonald, M.; Howard, J.

    1981-01-01

    The ventral thoracic skin of hamsters was irradiated with either single, split (two fractions given in 24 hr), or multiple (five fractions given daily) exposures of X rays or accelerated carbon ions using a 4-cm spread Bragg peak. Animals were positioned in the heavy-ion beam so that the ventral thoracic skin surface was 1 cm distal to the proximal peak of the modified beam. Early skin reactions from 6 to 30 days postirradiation were assessed. Using the average skin reactions produced in this period, it was found that the relative biological effect (RBE) for single doses of carbon ions was about 1.6 (5-17 Gy per fraction), for two fractions about 1.8 (5-17 Gy perfraction), and for five fractions about 1.9 (2.4-7.2 Gy per fraction). The fractional amount of sublethal damage repaired after carbon ion irradiation was about 0.3 (at dose levels of 2.4-8.0 Gy per fraction) compared to a value of about 0.45 (at dose levels of 60-13.0 Gy per fraction) found for the fractionated X irradiations, indicting about a 33% decrease in the relative amount of sublethal damage repaired after carbon ion irradiation in this position in the spread Bragg curve. Also, data were interpreted using plots of the reciprocal total dose needed to produce a given level of skin damage versus the dose per fraction used in the multifraction experiments, and of the RBE versus dose per fraction obtained from a nonparametric analysis of the responses. These approaches allow estimation of RBE at dose levels relevant to the clinical situation. Also, estimation may be made of the maximum permissible RBE by using the zero dose intercept value from the linear reciprocal dose plot. With this approach, the RBE at a dose level of 2 Gy is about 2.5 and the maximum RBE value is about 2.7

  20. Preparation of 18F in a research reactor, from irradiated lithium carbonate

    International Nuclear Information System (INIS)

    Gariglia, H.T.; Silva, C.P.G. da.

    1978-01-01

    A procedure for preparation of carrier - free fluorine-18 is described. The 18 F is produced by neutron irradiation of lithium carbonate and is separated by passing the dissolved material through a 1000 0 C calcinated aluminium oxyde column. The yield is about 90%, the tritium content 2%; other radioactive impurities are not found. The radiochemical purity is about 93% and the lithium content of the solution is [pt

  1. Preparation of iron oxide-impregnated spherical granular activated carbon-carbon composite and its photocatalytic removal of methylene blue in the presence of oxalic acid.

    Science.gov (United States)

    Kadirova, Zukhra C; Hojamberdiev, Mirabbos; Katsumata, Ken-Ichi; Isobe, Toshihiro; Matsushita, Nobuhiro; Nakajima, Akira; Sharipov, Khasan; Okada, Kiyoshi

    2014-01-01

    The spherical granular activated carbon-carbon composites (GAC-Fe) with different iron oxide contents (Fe mass% = 0.6-10) were prepared by a pore volume impregnation method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2-adsorption results confirm the presence of amorphous iron oxide, pyrolytic carbon, and graphitized globular carbon nanoparticles covered with amorphous carbon in the CAG-Fe. The rate of photodegradation of methylene blue (MB) in aqueous solution under UV light in the presence of oxalic acid correlates with porosity of the prepared materials. The total MB removal includes the combination of adsorption and photodegradation without the addition of H2O2. The results of total organic carbon (TOC) analysis reveal that the decolorization of MB in aqueous solution containing oxalic acid corresponds to the decomposition of organic compounds to CO2 and H2O.

  2. Reflectivity and filtering characteristics of pyrolytic graphite

    International Nuclear Information System (INIS)

    Adib, M.; Abdel-Kawy, A.; Ashry, A.; Abbas, Y.; Wahba, W.

    1988-01-01

    The neutron transmission measurements through oriented pyrolytic graphite (P.G. crystal) were carried out in the wavelength band from 0.15 nm to 6.5 nm at different orientations of the (002) plane of the crystal w.r.t. the neutron beam direction. It was found that the P.G. crystal may be tuned for optimum scattering of second-order neutrons in the wavelength ranging between 0.112 nm and 0.425 nm, by adjusting the filter in an appropriate orientation. The reflectivity of (002), (004) and (006) planes of P.G. were measured and the following results are obtained: the reflectivity of (002) plane was found to be 99% by (transmission method). The ratio of the integrated intensity of the reflected neutrons from (004) and (006) is 3.14+-0.25 and is found to be in agreement with the calculated ratio. The measurements were performed using the fixed scattering angle spectrometer installed in front of the ET-RR-1 reactor horizontal channel

  3. Characteristics of hydrogen evolution and oxidation catalyzed by Desulfovibrio caledoniensis biofilm on pyrolytic graphite electrode

    International Nuclear Information System (INIS)

    Yu Lin; Duan Jizhou; Zhao Wei; Huang Yanliang; Hou Baorong

    2011-01-01

    Highlights: → The sulphate-reducing bacteria (SRB) have the ability to catalyze the hydrogen evolution and oxidation on pyrolytic graphite electrode. → The SRB biofilm decreases the overpotential and electron transfer resistance by the CV and EIS detection. → The SRB biofilm can transfer electrons to the 0.24 V polarized pyrolytic graphite electrode and the maximum current is 0.035 mA, which is attributed to SRB catalyzed hydrogen oxidation. → The SRB biofilm also can obtain electron from the -0.61 V polarized PGE to catalyze the hydrogen evolution. - Abstract: Hydrogenase, an important electroactive enzyme of sulphate-reducing bacteria (SRB), has been discovered having the capacity to connect its activity to solid electrodes by catalyzing hydrogen evolution and oxidation. However, little attention has been paid to similar electroactive characteristics of SRB. In this study, the electroactivities of pyrolytic graphite electrode (PGE) coated with SRB biofilm were investigated. Two corresponding redox peaks were observed by cyclic voltammetry detection, which were related to the hydrogen evolution and oxidation. Moreover, the overpotential for the reactions decreased by about 0.2 V in the presence of the SRB biofilm. When the PGE coated with the SRB biofilm was polarized at 0.24 V (vs. SHE), an oxidation current related to the hydrogen oxidation was found. The SRB biofilm was able to obtain electrons from the -0.61 V (vs. SHE) polarized PGE to form hydrogen, and the electron transfer resistance also decreased with the formation of SRB biofilm, as measured by the non-destructive electrochemical impendence spectroscopy detection. It was concluded that the hydrogen evolution and oxidation was an important way for the electron transfer between SRB biofilm and solid electrode in anaerobic environment.

  4. Ion Prostate Irradiation (IPI) – a pilot study to establish the safety and feasibility of primary hypofractionated irradiation of the prostate with protons and carbon ions in a raster scan technique

    International Nuclear Information System (INIS)

    Habl, Gregor; Herfarth, Klaus; Hatiboglu, Gencay; Edler, Lutz; Uhl, Matthias; Krause, Sonja; Roethke, Matthias; Schlemmer, Heinz P; Hadaschik, Boris; Debus, Juergen

    2014-01-01

    Due to physical characteristics, ions like protons or carbon ions can administer the dose to the target volume more efficiently than photons since the dose can be lowered at the surrounding normal tissue. Radiation biological considerations are based on the assumption that the α/β value for prostate cancer cells is 1.5 Gy, so that a biologically more effective dose could be administered due to hypofractionation without increasing risks of late effects of bladder (α/β = 4.0) and rectum (α/β = 3.9). The IPI study is a prospective randomized phase II study exploring the safety and feasibility of primary hypofractionated irradiation of the prostate with protons and carbon ions in a raster scan technique. The study is designed to enroll 92 patients with localized prostate cancer. Primary aim is the assessment of the safety and feasibility of the study treatment on the basis of incidence grade III and IV NCI-CTC-AE (v. 4.02) toxicity and/or the dropout of the patient from the planned therapy due to any reason. Secondary endpoints are PSA-progression free survival (PSA-PFS), overall survival (OS) and quality-of-life (QoL). This pilot study aims at the evaluation of the safety and feasibility of hypofractionated irradiation of the prostate with protons and carbon ions in prostate cancer patients in an active beam technique. Additionally, the safety results will be compared with Japanese results recently published for carbon ion irradiation. Due to the missing data of protons in this hypofractionated scheme, an in depth evaluation of the toxicity will be created to gain basic data for a following comparison study with carbon ion irradiation. Clinical Trial Identifier: http://clinicaltrials.gov/show/NCT01641185 (clinicaltrials.gov)

  5. Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

    International Nuclear Information System (INIS)

    Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

    2007-01-01

    Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

  6. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    International Nuclear Information System (INIS)

    Costarrosa, L.; Calvino-Casilda, V.; Ferrera-Escudero, S.; Duran-Valle, C.J.; Martin-Aranda, R.M.

    2006-01-01

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N 2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation

  7. Uptake of carbon monoxide by C3H mice following X irradiation of lung only or total-body irradiation with 60Co

    International Nuclear Information System (INIS)

    Rappaport, D.S.; Niewoehner, D.E.; Kim, T.H.; Song, C.W.; Levitt, S.H.

    1983-01-01

    Carbon monoxide uptake (V/sub co/) and ventilation rate (VR) of C3H mice were determined at 14 weeks following either X irradiation of lungs only or total-body irradiation with 60 Co at different dose rates. Following localized X irradiation of lung at 97 /sub c/Gy/min there was a reduction in V/sub co/, which was inversely related to radiation dose, with a small reduction below control levels being detected at 7 Gy, the lowest dose tested. An increase in VR could be detected only at doses of 11 Gy, or more. Another group of animals received 11.5 Gy total-body irradiation at either 26.2 or 4.85 /sub c/Gy/min fllowed by transplantation with syngeneic bone marrow. Following total-body irradiation, V/sub co/ was significantly reduced by about 37% at the higher dose rate and 23% at the lower dose rate. In contrast, a trend toward elevated VR was detected only at the higher dose rate.The results indicate that V/sub co/ is a sensitive indicator of radiation-induced lung injury and that under the experimental conditions used V/sub co/ is a more sensitive indicator of radiation-induced lung injury in C3H mice than VR

  8. Physical and combustion characterization of pyrolytic oils derived from biomass material upgraded by catalytic hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Vitolo, S.; Ghetti, P. (Universita di Pisa, Pisa (Italy). Dipartimento di Ingegneria Chimica)

    1994-11-01

    Physical and combustion properties of a pyrolytic bio-oil are determined both as-obtained and after catalytic hydrodeoxygenation. The tests demonstrate that the hydrogenation treatment improves the oil as regards combustibility, viscosity and acidity. Combustion properties of the oil have been characterized by evaporation and temperature programmed combustion profiles. Short communication. 21 refs., 4 figs., 2 tabs.

  9. AGR-5/6/7 Irradiation Test Predictions using PARFUME

    Energy Technology Data Exchange (ETDEWEB)

    Skerjanc, William F. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-09-14

    PARFUME, (PARticle FUel ModEl) a fuel performance modeling code used for high temperature gas-cooled reactors (HTGRs), was used to model the Advanced Gas Reactor (AGR)-5/6/7 irradiation test using predicted physics and thermal hydraulics data. The AGR-5/6/7 test consists of the combined fifth, sixth, and seventh planned irradiations of the AGR Fuel Development and Qualification Program. The AGR-5/6/7 test train is a multi-capsule, instrumented experiment that is designed for irradiation in the 133.4-mm diameter north east flux trap (NEFT) position of Advanced Test Reactor (ATR). Each capsule contains compacts filled with uranium oxycarbide (UCO) unaltered fuel particles. This report documents the calculations performed to predict the failure probability of tristructural isotropic (TRISO)-coated fuel particles during the AGR-5/6/7 experiment. In addition, this report documents the calculated source term from the driver fuel. The calculations include modeling of the AGR-5/6/7 irradiation that is scheduled to occur from October 2017 to April 2021 over a total of 13 ATR cycles, including nine normal cycles and four Power Axial Locator Mechanism (PALM) cycle for a total between 500 – 550 effective full power days (EFPD). The irradiation conditions and material properties of the AGR-5/6/7 test predicted zero fuel particle failures in Capsules 1, 2, and 4. Fuel particle failures were predicted in Capsule 3 due to internal particle pressure. These failures were predicted in the highest temperature compacts. Capsule 5 fuel particle failures were due to inner pyrolytic carbon (IPyC) cracking causing localized stresses concentrations in the SiC layer. This capsule predicted the highest particle failures due to the lower irradiation temperature. In addition, shrinkage of the buffer and IPyC layer during irradiation resulted in formation of a buffer-IPyC gap. The two capsules at the two ends of the test train, Capsules 1 and 5 experienced the smallest buffer-IPyC gap

  10. Molecular Dynamics Simulation of Damage to Coiled Carbon Nanotubes under C Ion Irradiation

    International Nuclear Information System (INIS)

    Zhou Bin; Zhang Wei; Gong Wen-Bin; Wang Song; Ren Cui-Lan; Wang Cheng-Bin; Zhu Zhi-Yuan; Huai Ping

    2013-01-01

    The stability of coiled carbon nanotubes under C ion irradiation is investigated by molecular dynamics simulations. The defect statistics shows that small curvature coiled carbon nanotubes have better radiation tolerance than normal straight carbon nanotubes. To understand the effect of the curvature on defect production, the threshold displacement energies for the upper and lower walls, as well as those for the side parts, are calculated. The results show that the lower wall has better radiation tolerance than the upper wall. For the upper wall, a small increase in the curvature of nanotube axis gives rise to an increase in the radiation tolerance and then a decrease with the curvature becomes larger. However, for the lower wall, as the curvature of the nanotube axis increases, the radiation tolerance increases as the bonds compressed slightly in our simulation

  11. Interfacial adhesion improvement in carbon fiber/carbon nanotube reinforced hybrid composites by the application of a reactive hybrid resin initiated by gamma irradiation

    Science.gov (United States)

    Szebényi, G.; Faragó, D.; Lámfalusi, Cs.; Göbl, R.

    2018-04-01

    Interfacial adhesion is a key factor in composite materials. The effective co-working of the reinforcing materials and matrix is essential for the proper load transfer between them, and to achieve the desired reinforcing effect. In case of nanocomposites, especially carbon nanotube (CNT) reinforced nanocomposites the adhesion between the CNTs and the polymer matrix is poor. To improve the interfacial adhesion and exploit the reinforcing effect of these nanoparticles a two step curable epoxy (EP)/vinylester (VE) hybrid resin system was developed where the EP is cured using hardener in the first step, during the composite production, and in the second step the curing of the VE is initiated by gamma irradiation, which also activates the reinforcing materials and the cured matrix component. A total of six carbon fiber reinforced composite systems were compared with neat epoxy and EP/VE hybrid matrices with and without chemical initiator and MWCNT nano-reinforcement. The effect of gamma irradiation was investigated at four absorbed dose levels. According to our three point bending and interlaminar shear test results the adhesion has improved between all constituents of the composite system. It was demonstrated that gamma irradiation has beneficial effect on the static mechanical, especially interlaminar properties of both micro- and nanocomposites in terms of modulus, strength and interlaminar shear strength.

  12. Neutron transmission through pyrolytic graphite crystals

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt); Habib, N. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt)]. E-mail: nadiahabib15@yahoo.com; Fathaalla, M. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt)

    2006-05-15

    Calculation of the total cross-section, neutron transmission and removal coefficient of pyrolytic graphite (PG) for thermal neutron energies were carried out using an additive formula. The formula takes into account the variation of thermal diffuse and Bragg scattering cross-sections in terms of PG temperature and mosaic spread for neutron energies in the range 1 meV to 1 eV. A computer code PG has been developed which allow calculations for the graphite in its hexagonal close-packed structure, when its c-direction is parallel with incident neutron beam (parallel orientation). The calculated total neutron cross-sections for PG in parallel orientation at different mosaic spreads were compared with the measured values. An overall agreement is indicated between the formula fits and experimental data at room and liquid nitrogen temperatures. A feasibility study for use of PG crystals as second-order neutron filter is detailed in terms of mosaic spread, optimum thickness and temperature. The calculated removal coefficients of PG crystals show that such crystals are high efficiency second-order filter within neutron energy intervals (4-7 meV) and (10-15 meV)

  13. Mass spectrometric characterization of a pyrolytic radical source using femtosecond ionization

    Energy Technology Data Exchange (ETDEWEB)

    Frey, H M; Beaud, P; Mischler, B; Radi, P P; Tzannis, A P; Gerber, T [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Radicals play, as reactive species, an important role in the chemistry of combustion. In contrast to atmospheric flames where spectra are congested due to high vibrational and rotational excitation, experiments in the cold environment of a molecular beam (MB) yield clean spectra that can be easily attributed to one species by Resonantly Enhanced Multi Photon Ionization (REMP). A pyrolytic radical source has been set up. To characterize the efficiency of the source `soft` ionization with femto second pulses is applied which results in less fragmentation, simplifying the interpretation of the mass spectrum. (author) figs., tabs., refs.

  14. SOFT X-RAY IRRADIATION OF PURE CARBON MONOXIDE INTERSTELLAR ICE ANALOGUES

    Energy Technology Data Exchange (ETDEWEB)

    Ciaravella, A.; Candia, R.; Collura, A. [INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Jimenez-Escobar, A.; Munoz Caro, G. M. [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Cecchi-Pestellini, C. [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Italy); Giarrusso, S. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Barbera, M., E-mail: aciaravella@astropa.unipa.it [Dipartimento di Scienze Fisiche and Astronomiche, Universita di Palermo, Sezione di Astronomia, Piazza del Parlamento 1, I-90134 Palermo (Italy)

    2012-02-10

    There is an increasing evidence for the existence of large organic molecules in the interstellar and circumstellar medium. Very few among such species are readily formed in conventional gas-phase chemistry under typical conditions of interstellar clouds. Attention has therefore focused on interstellar ices as a potential source of these relatively complex species. Laboratory experiments show that irradiation of interstellar ice analogues by fast particles or ultraviolet radiation can induce significant chemical complexity. However, stars are sources of intense X-rays at almost every stage of their formation and evolution. Such radiation may thus provide chemical changes in regions where ultraviolet radiation is severely inhibited. After H{sub 2}O, CO is often the most abundant component of icy grain mantles in dense interstellar clouds and circumstellar disks. In this work we present irradiation of a pure carbon monoxide ice using a soft X-ray spectrum peaked at 0.3 keV. Analysis of irradiated samples shows formation of CO{sub 2}, C{sub 2}O, C{sub 3}O{sub 2}, C{sub 3}, C{sub 4}O, and CO{sub 3}/C{sub 5}. Comparison of X-rays and ultraviolet irradiation experiments, of the same energy dose, shows that X-rays are more efficient than ultraviolet radiation in producing new species. With the exception of CO{sub 2}, X-ray photolysis induces formation of a larger number of products with higher abundances, e.g., C{sub 3}O{sub 2} column density is about one order of magnitude higher in the X-ray experiment. To our knowledge this is the first report on X-ray photolysis of CO ices. The present results show that X-ray irradiation represents an efficient photo-chemical way to convert simple ices to more complex species.

  15. Effect of lithium carbonate on leukocyte number after influence of ionizing radiation. 3. Influence of lithium carbonate on peripheral leukocytes after fractionated caudal half-body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rose, H.; Saul, G.; Kehrberg, G. (Humboldt-Universitaet, Berlin (German Democratic Republic). Bereich Medizin (Charite))

    1985-01-01

    Fractionated half-body irradiation of rats resulted in leukopenia of the peripheral blood. The decrease of leukocytes was smaller in animals pretreated with an orally administered dose of lithium carbonate for 14 days.

  16. Catalytic fast pyrolysis of biomass impregnated with potassium phosphate in a hydrogen atmosphere for the production of phenol and activated carbon

    Science.gov (United States)

    Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

    2018-02-01

    A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550 oC in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1605 m2/g.

  17. Electronic excitation induced modifications in elongated iron nanoparticle encapsulated multiwalled carbon nanotubes under ion irradiation

    Science.gov (United States)

    Saikiran, V.; Bazylewski, P.; Sameera, I.; Bhatia, Ravi; Pathak, A. P.; Prasad, V.; Chang, G. S.

    2018-05-01

    Multi-wall carbon nanotubes (MWCNT) filled with Fe nanorods were shown to have contracted and deformed under heavy ion irradiation. In this study, 120 MeV Ag and 80 MeV Ni ion irradiation was performed to study the deformation and defects induced in iron filled MWCNT under heavy ion irradiation. The structural modifications induced due to electronic excitation by ion irradiation were investigated employing high-resolution transmission electron microscopy, micro-Raman scattering experiments, and synchrotron-based X-ray absorption and emission spectroscopy. We understand that the ion irradiation causes modifications in the Fe nanorods which result in compressions and expansions of the nanotubes, and in turn leads to the buckling of MWCNT. The G band of the Raman spectra shifts slightly towards higher wavenumber and the shoulder G‧ band enhances with the increase of ion irradiation fluence, where the buckling wavelength depends on the radius 'r' of the nanotubes as exp[(r)0.5]. The intensity ratio of the D to G Raman modes initially decreases at the lowest fluence, and then it increases with the increase in ion fluence. The electron diffraction pattern and the high resolution images clearly show the presence of ion induced defects on the walls of the tube and encapsulated iron nanorods.

  18. Carbon/hydrogen clusters [CnHx+] formation from laser irradiation of coronene

    International Nuclear Information System (INIS)

    Betancourt, F; Alvarez, I; Guerrero, A; Cisneros, C; Poveda, J C

    2015-01-01

    This article presents the photo induced dehydrogenation of a cooled molecular jet of coronene, exposed to 266 nm laser radiation. Using unfocused laser radiation of 1064 nm, synchronously coupled with the ionization laser pulses, a system recently developed. Molecular beams were produced by laser desorption of coronene. Analysis of the photoproducts made by time-of flight mass spectrometer showed that a wide variety of ionic species were formed; more than 300 different species were observed. The results showed carbon clusters C + n with n up to 24 as well as carbon/hydrogen clusters C + n H + x with masses higher than 300 m/z. The effect on the laser irradiance on the formation of different ions, in the rage from 10 9 W/cm2 to 10 10 W/cm2, is discussed as it is reflected on the evolution from the big ions to the smaller ones. (paper)

  19. Vitamin C, added after irradiation, reduces the mutant yield and alters the spectrum of CD59- mutations in AL cells irradiated with high LET carbon ions

    International Nuclear Information System (INIS)

    Ueno, A.M.; Vannais, D.B.; Lenarczyk, M.; Waldren, C.A.

    2003-01-01

    Miazaki, Watanabe, Kumagai and their colleagues reported that induction of HPRT - mutants by X-rays in cultured human cells was prevented by vitamin C (ascorbate) added 30 minutes after irradiation. They provided data that mutation extinction was due to neutralization by vitamin C of radiation-induced long-lived mutagenic radicals (LLR) with half-lives of several hours. We find that post-irradiation treatment with vitamin C reduces, but does not eliminate, the induction of CD59 - mutants in human-hamster hybrid A L cells exposed to high-LET carbon ions (LET of 100 keV/μm). The lethality of the carbon ions was not altered by vitamin C. Preliminary experiments indicate that post-radiation addition of vitamin C also changes the quality of CD59 - mutations induced by the carbon beam. The change in spectrum is seen as a reduction in prevalence of small mutations (not detectable by PCR) and of mutants displaying transmissible genomic instability (TGI) measured by chromosome translocation frequencies. Our results confirm the essential effect of vitamin C on X-ray induced mutation and suggest a role for LLR in genomic instability. (author)

  20. Irradiation performance of AGR-1 high temperature reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Demkowicz, Paul A., E-mail: paul.demkowicz@inl.gov [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Hunn, John D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Ploger, Scott A. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Morris, Robert N.; Baldwin, Charles A. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Harp, Jason M.; Winston, Philip L. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Gerczak, Tyler J. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States); Rooyen, Isabella J. van [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States); Montgomery, Fred C.; Silva, Chinthaka M. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6093 (United States)

    2016-09-15

    the nature and causes of SiC coating failure in high-quality TRISO fuel. In general, changes in coating morphology were found to be dominated by the behavior of the buffer and inner pyrolytic carbon (IPyC), and infrequently observed SiC layer damage was usually related to cracks in the IPyC. Palladium attack of the SiC layer was relatively minor, except for the particles that released cesium during irradiation, where SiC corrosion was found adjacent to IPyC cracks. Palladium, silver, and uranium were found in the SiC layer of irradiated particles, and characterization of these elements within the SiC microstructure is the subject of ongoing focused study.

  1. Native and denatured forms of proteins can be discriminated at edge plane carbon electrodes

    Czech Academy of Sciences Publication Activity Database

    Ostatná, Veronika; Černocká, Hana; Kurzatkowska, K.; Paleček, Emil

    2012-01-01

    Roč. 735, JUL (2012), s. 31-36 ISSN 0003-2670 R&D Projects: GA AV ČR(CZ) KJB100040901; GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038 Institutional research plan: CEZ:AV0Z50040702 Keywords : protein denaturation * carbon electrodes * edge plane pyrolytic graphite Subject RIV: BO - Biophysics Impact factor: 4.387, year: 2012

  2. Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

    Science.gov (United States)

    Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

    2014-01-01

    The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

  3. Low-dose carbon ion irradiation effects on DNA damage and oxidative stress in the mouse testis

    Science.gov (United States)

    Liu, Yang; Long, Jing; Zhang, Luwei; Zhang, Hong; Liu, Bin; Zhao, Weiping; Wu, Zhehua

    2011-01-01

    To investigate the effects of low-dose carbon ion irradiation on reproductive system of mice, the testes of outbred Kunming strain mice were whole-body irradiated with 0, 0.05, 0.1, 0.5 and 1 Gy, respectively. We measured DNA double-strand breaks (DNA DSBs) and oxidative stress parameters including malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and testis weight and sperm count at 12 h, 21 d and 35 d after irradiation in mouse testis. At 12 h postirradiation, a significant increase in DNA DSB level but no pronounced alterations in MDA content or SOD activity were observed in 0.5 and 1 Gy groups compared with the control group. At 21 d postirradiation, there was a significant reduction in sperm count and distinct enhancements of DSB level and MDA content in 0.5 and 1 Gy groups in comparison with control. At 35 d postirradiation, the levels of DNA DSBs and MDA, and SOD activity returned to the baseline except for the MDA content in 1 Gy (P sperm count were still observed in 0.5 (P sperm count. Furthermore, these data suggest that the deleterious effects may be chronic or delayed in reproductive system after whole-body exposure to acute high-dose carbon ions.

  4. Effect of gamma-irradiation on structural and electrical properties of poly(bisphenol-A carbonate) films

    International Nuclear Information System (INIS)

    Kalkar, A.K.; Kundagol, S.

    1992-01-01

    Post-irradiation studies on poly(bisphenol-A carbonate) (PC) have been made to obtain information on the changes in structural and electrical properties. PC films were irradiated in air at room temperature with a 60 Co γ-source at different dosages. No new lines characteristic of crystalline phase were observed in the X-ray diffraction pattern. Glass transition temperature decreased from 422 K for the unirradiated sample to 407 K for the sample irradiated with the maximum dose (0.68 M Gy). Electrical conductivity of PC was studied in an M/P/M sandwich configuration in the temperature range of 298-353 K and applied voltage range of 100-2000 V. No change in the conduction mechanism was observed when compared to unirradiated sample. However, magnitude of current gradually decreased for the unirradiated sample. For the sample irradiated with the maximum dose (0.68 MGy). Changes in these properties were explained on the basis of a decrease in average molecular weight and changes in the chemical structure. (Author)

  5. Monte Carlo simulations of prompt-gamma emission during carbon ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Le Foulher, F.; Bajard, M.; Chevallier, M.; Dauvergne, D.; Henriquet, P.; Ray, C.; Testa, E.; Testa, M. [Universite de Lyon 1, F-69003 Lyon (France); IN2P3/CNRS, UMR 5822, Institut de Physique Nucleaire de Lyon, F-69622 Villeurbanne (France); Freud, N.; Letang, J. M. [Laboratoire de Controles Non Destructifs Par Rayonnements Ionisants, INSA-Lyon, F-69621 Villeurbanne cedex (France); Karkar, S. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Plescak, R.; Schardt, D. [Gesellschaft fur Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)

    2009-07-01

    Monte Carlo simulations based on the Geant4 tool-kit (version 9.1) were performed to study the emission of secondary prompt gamma-rays produced by nuclear reactions during carbon ion-beam therapy. These simulations were performed along with an experimental program and instrumentation developments which aim at designing a prompt gamma-ray device for real-time control of hadron therapy. The objective of the present study is twofold: first, to present the features of the prompt gamma radiation in the case of carbon ion irradiation; secondly, to simulate the experimental setup and to compare measured and simulated counting rates corresponding to various experiments. For each experiment, we found that simulations overestimate prompt gamma-ray detection yields by a factor of 12. Uncertainties in fragmentation cross sections and binary cascade model cannot explain such discrepancies. The so-called 'photon evaporation' model is therefore questionable and its modification is currently in progress. (authors)

  6. Presence de Carbone-13 dans les elements combustibles de type (U,Pu)O 2 irradies en reacteur rapide

    Science.gov (United States)

    Kryger, Bernard; Hagemann, Robert

    1982-06-01

    Du carbone-13 produit par la réaction de capture neutronique 168O + 10n → 136C + 42He se forme dans les combustibles de type oxyde irradiés en neutrons rapides. Cette réaction, dont le seuil d'énergie se situe à 2.35 MeV, conduit à la formation d'une quantité de carbone-13 qui peut varier notablement suivant le spectre neutronique du réacteur (entre 20 et 40 × 10 -6g 13C/g (U,Pu)O 2 pour une fluence de 2 × 10 23 n/cm 2). DES mesures effectuées sur le combustible et la gaine par spectrométrie de masse après irradiation montrent qu'une fraction égale ou supérieure à la moitié du carbone-13 produit dans l'oxyde peut être transférée dans la gaine. Un tel comportement nous fait considérer le carbone-13 comme un véritable marqueur du carbone plus généralement contenu dans l'oxyde et, à ce titre, la détection de cet isotope devrait contribuer à élucider tout particulièrement les mécanismes de carburation de la gaine par les combustibles (U,Pu)O 2 des réacteurs surgénérateurs.

  7. Wound healing in porcine skin following low-output carbon dioxide laser irradiation of the incision

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.K.; Garden, J.M.; Taute, P.M.; Leibovich, S.J.; Lautenschlager, E.P.; Hartz, R.S.

    1987-06-01

    Wound healing of scalpel incisions to the depth of adipose tissue closed with conventional methods was compared with closure by low-output carbon dioxide laser irradiation. In 3 Pitman-Moore minipigs wound healing was evaluated at intervals from 1 to 90 days by the following methods: clinical variables of wound healing; formation of the basement membrane components bullous pemphigoid antigen, laminin, and fibronectin; and histological evaluation of the regeneration of the epidermis, neovascularization, and elastin and collagen formation. There was no significant difference in healing between wounds closed by the various conventional methods and by the low-output carbon dioxide laser.

  8. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance

    Directory of Open Access Journals (Sweden)

    Thijs Leendert Pons

    2014-02-01

    Full Text Available Plant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A partitioned in C available for growth and C required for respiration (R, is thus irradiance dependent. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 µmol m-2 s-1 (1.2 mol m-2 day-1 to 500 µmol m-2 s-1 (30 mol m-2 day-1. Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies towards a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated with a superior C

  9. Catalytic Fast Pyrolysis of Biomass Impregnated with Potassium Phosphate in a Hydrogen Atmosphere for the Production of Phenol and Activated Carbon

    Science.gov (United States)

    Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

    2018-01-01

    A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1,605 m2/g. PMID:29515994

  10. Absence of field anisotropy in the intrinsic ferromagnetic signals of highly oriented pyrolytic graphite

    International Nuclear Information System (INIS)

    Ballestar, A.; Setzer, A.; Esquinazi, P.; Garcia, N.

    2011-01-01

    We have measured the magnetization of bulk samples of highly oriented pyrolytic graphite (HOPG) at magnetic fields applied parallel and perpendicular to the graphene layers. Within experimental error the intrinsic ferromagnetic signals of the samples show similar magnetic moments at saturation for the two magnetic field directions, in contrast to recently published data (J. Cervenka et al., Nat. Phys. 5 (2009) 840). To check that the SQUID device provides correctly the small ferromagnetic signals obtained after subtracting the 100 times larger diamagnetic background, we have prepared a sample with a superconducting Pb-film deposited on one of the HOPG surfaces. We show that the field dependence of the measured magnetic moment and after the background subtraction is highly reliable even in the sub-μ emu range providing the real magnetic properties of the embedded small ferromagnetic and superconducting signals. - Research Highlights: → We have measured the magnetization of bulk samples of highly oriented pyrolytic graphite (HOPG) at magnetic fields applied parallel and perpendicular to the graphene layers.→ Within experimental error the intrinsic ferromagnetic signals of the samples show similar magnetic moments at saturation for the two magnetic field directions.→ The absence of magnetic anisotropy of the intrinsic ferromagnetic order found in HOPG samples contrasts recently published data by Cervenka et al., Nat Phys 5, 840 (2009).

  11. Tumor induction in mice after local irradiation with single doses of either carbon-ion beams or gamma rays.

    Science.gov (United States)

    Ando, Koichi; Koike, Sachiko; Ohmachi, Yasushi; Ando, Yutaka; Kobashi, Gen

    2014-12-01

    To determine the dose-dependent relative biological effectiveness (RBE) for tumor prevalence in mice receiving single localized doses to their right leg of either carbon ions (15, 45 or 75 keV/μm) or 137Cs gamma rays. A total of 1647 female C3H mice were irradiated to their hind legs with a localized dose of either reference gamma rays or 15, 45 or 75 keV/μm carbon-ion beams. Irradiated mice were evaluated for tumors twice a month during their three-year life span, and the dimensions of any tumors found were measured with a caliper. The tumor induction frequency was calculated by Kaplan-Meier analysis. The incidence of tumors from 50 Gy of 45 keV/μm carbon ions was marginally higher than those from 50 Gy of gamma rays. However, 60 Gy of 15 keV/μm carbon ions induced significantly fewer tumors than did gamma rays. RBE values of 0.87 + 0.12, 1.29 + 0.08 or 2.06 + 0.39 for lifetime tumorigenesis were calculated for 15, 45 or 75 keV/μm carbon-ion beams, respectively. Fibrosarcoma predominated, with no Linear Energy Transfer (LET)-dependent differences in the tumor histology. Experiments measuring the late effect of leg skin shrinkage suggested that the carcinogenic damage of 15 keV/μm carbon ions would be less than that of gamma rays. We conclude that patients receiving radiation doses to their normal tissues would face less risk of secondary tumor induction by carbon ions of intermediate LET values compared to equivalent doses of photons.

  12. Effect of high surface area activated carbon on thermal degradation of jet fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gergova, K.; Eser, S.; Arumugam, R.; Schobert, H.H. [Pennsylvania State Univ., University Park, PA (United States)

    1995-05-01

    Different solid carbons added to jet fuel during thermal stressing cause substantial changes in pyrolytic degradation reactions. Activated carbons, especially high surface area activated carbons were found to be very effective in suppressing solid deposition on metal reactor walls during stressing at high temperatures (425 and 450{degrees}C). The high surface area activated carbon PX-21 prevented solid deposition on reactor walls even after 5h at 450{degrees}C. The differences seen in the liquid product composition when activated carbon is added indicated that the carbon surfaces affect the degradation reactions. Thermal stressing experiments were carried out on commercial petroleum-derived JPTS jet fuel. We also used n-octane and n-dodecane as model compounds in order to simplify the study of the chemical changes which take place upon activated carbon addition. In separate experiments, the presence of a hydrogen donor, decalin, together with PX-21 was also studied.

  13. Alternative waste form development: low-temperature pyrolytic-carbon coatings

    International Nuclear Information System (INIS)

    Oma, K.H.; Rusin, J.M.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Large simulted waste-forms can be coated with PyC in screw-agitated coater (SAC) at low temperatures. Higher coating rates are obtained using Ni(CO) 4 as a catalyst rather than Fe(CO) 5 or Co(AcAc) 2 ; coating quality and deposition rates are improved when C 2 H 2 is used as carbon-source gas rather than methane, propane, heptane and toluene; H 2 is a better carrier gas than Ar or N 2 . Improved coating quality and deposition rates are obtained with H 2 ; deposition rates increase with Ni(CO) 4 concentration, C 2 H 2 concentration and reaction temperature. Increasing the Ni(CO) 4 and C 2 H 2 concentrations reduces the quality of the coatings; however, better adhesion of the coating to the substrate is obtained as temperature is increased; highest quality catalyzed PyC coatings have been obtained using 0.001 and 0.01 mole % Ni(CO) 4 , 1.5 to 3.0 mole % C 2 H 2 , and the balance H 2 at 425 and 525 0 C; and deposition rates are higher in the fluidized bed coater than the SAC

  14. Pyrolytic Graphite as a Selective Neutron Filter

    International Nuclear Information System (INIS)

    Adib, M.; Habib, N.; Fathalla, M.

    2006-01-01

    The transmission of neutrons through pyrolytic graphite (PG) crystals, set at different angles with respect to incident beam, were calculated using an additive formula. A computer program HOPG was developed to provide the required calculation. An overall agreement between the calculated neutron transmissions through a slab of 1,85 mm thick PG crystal with an angular spread of c-axes of 0,4 degree, set at different angles to the incident beam, and the available experimental ones in the wavelength range from (0,02 to 1,4) nm were obtained. A feasibility study for use of PG crystal as an efficient second-order neutron filter is detailed in terms of crystal thickness, angular spread of c-axes and its operation with respect to the neutron beam. It was shown that a PG crystal with an angular spread of c-axes and its orientation with respect to the neutron beam. It was shown that a PG crystal with an angular spread of 0,8 degree is sufficient for optimum scattering of second-order neutrons in the wavelength band (0,384-0,183) nm, by adjusting the filter in an appropriate orientation

  15. Irradiation With Carbon Ion Beams Induces Apoptosis, Autophagy, and Cellular Senescence in a Human Glioma-Derived Cell Line

    International Nuclear Information System (INIS)

    Jinno-Oue, Atsushi; Shimizu, Nobuaki; Hamada, Nobuyuki; Wada, Seiichi; Tanaka, Atsushi; Shinagawa, Masahiko; Ohtsuki, Takahiro; Mori, Takahisa; Saha, Manujendra N.; Hoque, Ariful S.; Islam, Salequl; Kogure, Kimitaka; Funayama, Tomoo; Kobayashi, Yasuhiko

    2010-01-01

    Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions). Methods and Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342. Induction of autophagy was examined either by staining cells with monodansylcadaverine (MDC) or by Western blotting to detect conversion of microtuble-associated protein light chain 3 (MAP-LC3) (LC3-I) to the membrane-bound form (LC3-II). Cellular senescence markers including induction of senescence-associated β-galactosidase (SA-β-gal) were examined. The mean telomere length of irradiated cells was determined by Southern blot hybridization. Expression of tumor suppressor p53 and cyclin/cyclin-dependent kinase inhibitor p21 WAF1/CIP1 in the irradiated cells was analyzed by Western blotting. Results: When NP-2 cells were irradiated with C-ions at 6 Gy, the major population of the cells died of apoptosis and autophagy. The residual fraction of attached cells ( WAF1/CIP1 was induced in NP-2 cells after irradiation. Furthermore, we found that irradiation with C-ions induced cellular senescence in a human glioma cell line lacking functional p53. Conclusions: Irradiation with C-ions induced apoptosis, autophagy, and cellular senescence in human glioma cells.

  16. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance.

    Science.gov (United States)

    Pons, Thijs L; Poorter, Hendrik

    2014-01-01

    The carbon balance is defined here as the partitioning of daily whole-plant gross CO2 assimilation (A) in C available for growth and C required for respiration (R). A scales positively with growth irradiance and there is evidence for an irradiance dependence of R as well. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 μmol m(-2) s(-1) (1.2 mol m(-2) day(-1)) to 500 μmol m(-2) s(-1) (30 mol m(-2) day(-1)). Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area) at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light-saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies toward a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated

  17. Field emission from the surface of highly ordered pyrolytic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Knápek, Alexandr, E-mail: knapek@isibrno.cz [Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno (Czech Republic); Sobola, Dinara; Tománek, Pavel [Department of Physics, FEEC, Brno University of Technology, Technická 8, Brno (Czech Republic); Pokorná, Zuzana; Urbánek, Michal [Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno (Czech Republic)

    2017-02-15

    Highlights: • HOPG shreds were created and analyzed in the UHV conditions. • Current-voltage measurements have been done to confirm electron tunneling, based on the Fowler-Nordheim theory. • Surface was characterized by other surface evaluation methods, in particular by: SNOM, SEM and AFM. - Abstract: This paper deals with the electrical characterization of highly ordered pyrolytic graphite (HOPG) surface based on field emission of electrons. The effect of field emission occurs only at disrupted surface, i.e. surface containing ripped and warped shreds of the uppermost layers of graphite. These deformations provide the necessary field gradients which are required for measuring tunneling current caused by field electron emission. Results of the field emission measurements are correlated with other surface characterization methods such as scanning near-field optical microscopy (SNOM) or atomic force microscopy.

  18. Field emission from the surface of highly ordered pyrolytic graphite

    International Nuclear Information System (INIS)

    Knápek, Alexandr; Sobola, Dinara; Tománek, Pavel; Pokorná, Zuzana; Urbánek, Michal

    2017-01-01

    Highlights: • HOPG shreds were created and analyzed in the UHV conditions. • Current-voltage measurements have been done to confirm electron tunneling, based on the Fowler-Nordheim theory. • Surface was characterized by other surface evaluation methods, in particular by: SNOM, SEM and AFM. - Abstract: This paper deals with the electrical characterization of highly ordered pyrolytic graphite (HOPG) surface based on field emission of electrons. The effect of field emission occurs only at disrupted surface, i.e. surface containing ripped and warped shreds of the uppermost layers of graphite. These deformations provide the necessary field gradients which are required for measuring tunneling current caused by field electron emission. Results of the field emission measurements are correlated with other surface characterization methods such as scanning near-field optical microscopy (SNOM) or atomic force microscopy.

  19. On the adsorption and kinetics of phase transients of adenosine at the different carbon electrodes modified with a mercury layer

    Czech Academy of Sciences Publication Activity Database

    Hasoň, Stanislav; Simonaho, S.P.; Silvennoinen, R.; Vetterl, Vladimír

    2003-01-01

    Roč. 48, č. 6 (2003), s. 651-668 ISSN 0013-4686 R&D Projects: GA AV ČR IAA4004002; GA AV ČR IBS5004107 Institutional research plan: CEZ:AV0Z5004920 Keywords : glassy carbon electrode * pyrolytic graphite electrode * mercury film electrode Subject RIV: BO - Biophysics Impact factor: 1.996, year: 2003

  20. Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

    International Nuclear Information System (INIS)

    Moritake, T.; Nose, T.; Tsuboi, K.; Anzai, K.; Ikota, N.; Ozawa, T.; Ando, K.

    2003-01-01

    The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/μm, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/μm. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 μM to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/μm. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation

  1. Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

    Energy Technology Data Exchange (ETDEWEB)

    Moritake, T; Nose, T [University of Tsukuba, (Japan); Tsuboi, K [Institute of Clinical Medical Center, (Japan); Anzai, K; Ikota, N [National Institute of Radiological Sciences, (Japan); Ozawa, T [Redox Regulation Research Group, (Japan); Ando, K [Research Center of Charged Particle Therapy, (Japan). National Institution

    2003-07-01

    The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/{mu}m, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/{mu}m. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 {mu}M to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/{mu}m. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation.

  2. Comparison Between In-Beam and Offline Positron Emission Tomography Imaging of Proton and Carbon Ion Therapeutic Irradiation at Synchrotron- and Cyclotron-Based Facilities

    International Nuclear Information System (INIS)

    Parodi, Katia; Bortfeld, Thomas; Haberer, Thomas

    2008-01-01

    Purpose: The benefit of using dedicated in-beam positron emission tomography (PET) detectors in the treatment room instead of commercial tomographs nearby is an open question. This work quantitatively compares the measurable signal for in-beam and offline PET imaging, taking into account realistic acquisition strategies at different ion beam facilities. Both scenarios of pulsed and continuous irradiation from synchrotron and cyclotron accelerators are considered, because of their widespread use in most carbon ion and proton therapy centers. Methods and Materials: A mathematical framework is introduced to compare the time-dependent amount and spatial distribution of decays from irradiation-induced isotope production. The latter is calculated with Monte Carlo techniques for real proton treatments of head-and-neck and paraspinal tumors. Extrapolation to carbon ion irradiation is based on results of previous phantom experiments. Biologic clearance is modeled taking into account available data from previous animal and clinical studies. Results: Ratios between the amount of physical decays available for in-beam and offline detection range from 40% to 60% for cyclotron-based facilities, to 65% to 110% (carbon ions) and 94% to 166% (protons) at synchrotron-based facilities, and increase when including biologic clearance. Spatial distributions of decays during irradiation exhibit better correlation with the dose delivery and reduced influence of biologic processes. Conclusions: In-beam imaging can be advantageous for synchrotron-based facilities, provided that efficient PET systems enabling detection of isotope decays during beam extraction are implemented. For very short (<2 min) irradiation times at cyclotron-based facilities, a few minutes of acquisition time after the end of irradiation are needed for counting statistics, thus affecting patient throughput

  3. Micro-bubble generated by laser irradiation on an individual carbon nanocoil

    International Nuclear Information System (INIS)

    Sun, Yanming; Pan, Lujun; Liu, Yuli; Sun, Tao

    2015-01-01

    Highlights: • We have investigated laser irradiated microbubbles which can be generated at fixed point on surface of an individual carbon nanocoil (CNC) immerged in deionized water. • The microbubble can be operated easily and flexibly. • Based on classical heat and mass transfer theories, the bubble growth data is in good agreement with the simplified model. - Abstract: We have investigated the micro-bubbles generated by laser induction on an individual carbon nanocoil (CNC) immerged in deionized water. The photon energy of the incident focused laser beam is absorbed by CNC and converted to thermal energy, which efficiently vaporizes the surrounding water, and subsequently a micro-bubble is generated at the laser location. The dynamics behavior of bubble generation, including its nucleation, expansion and steady-state, has been studied experimentally and theoretically. We have derived equations to analyze the expansion process of a bubble based on classical heat and mass transfer theories. The conclusion is in good agreement with the experiment. CNC, which acts as a realistic micro-bubble generator, can be operated easily and flexibly

  4. The effect of low temperature neutron irradiation and annealing on the thermal conductivity of advanced carbon-based materials

    International Nuclear Information System (INIS)

    Barabash, V.; Mazul, I.; Latypov, R.; Pokrovsky, A.; Wu, C.H.

    2002-01-01

    Several carbon-based materials (carbon fibre composites NB 31, NS 31 and UAM-92, doped graphite RGTi-91), were irradiated at about 90 deg. C in the damage dose range 0.0021-0.13 dpa. Significant reduction of the thermal conductivity of all materials was observed (e.g. at damage dose of ∼0.13 dpa the thermal conductivity degraded up to level of ∼2-3% of the initial values). However, saturation of this effect was observed starting at a dose of ∼0.06 dpa. The effect of annealing at 250 and 350 deg. C on the recovery of thermal conductivity of NB 31 and NS 31 was studied and it was shown this annealing can significantly improve thermal conductivity (∼2.5-3 times). The data on the degradation of the thermal conductivity after additional irradiation after annealing is also reported

  5. A comparison of effects between accelerated heavy ion irradiation and X-irradiation on the development of rat cerebellum

    International Nuclear Information System (INIS)

    Inouye, Minoru; Hayasaka, Shizu; Murata, Yoshiharu; Takahashi, Sentaro; Kubota, Yoshihisa

    1999-01-01

    The purpose of this experiment is to compare the effects of 290 MeV/u carbon-ion irradiation and X-irradiation on the development of rat cerebellum. Pregnant rats were exposed to carbon-ion beams at a single dose of 1.5 Gy on day 19.0 of gestation. Other groups of pregnant rats were exposed to X-rays on day 19.0 at single doses of 1.5, 2.0 and 2.5 Gy. Their fetuses were removed 8 hr after exposure, and an acute effect examined microscopically for cell death in the external granular layer of the cerebellum. Other dams were allowed to give birth and rear their litters. The offspring were sacrificed at 6 weeks of age, and their cerebella were examined for foliar malformation. The results showed that the effect of 1.5 Gy carbon-ion irradiation on the development of cerebellum was stronger than that of 1.5 Gy X-irradiation and similar to 2.0-2.5 Gy X-irradiation. (author)

  6. Imparting improvements in electrochemical sensors: evaluation of different carbon blacks that give rise to significant improvement in the performance of electroanalytical sensing platforms

    International Nuclear Information System (INIS)

    Vicentini, Fernando Campanhã; Ravanini, Amanda E.; Figueiredo-Filho, Luiz C.S.; Iniesta, Jesús; Banks, Craig E.; Fatibello-Filho, Orlando

    2015-01-01

    Three different carbon black materials have been evaluated as a potential modifier, however, only one demonstrated an improvement in the electrochemical properties. The carbon black structures were characterised with SEM, XPS and Raman spectroscopy and found to be very similar to that of amorphous graphitic materials. The modifications utilised were constructed by three different strategies (using ultrapure water, chitosan and dihexadecylphosphate). The fabricated sensors are electrochemically characterised using N,N,N',N'-tetramethyl-para-phenylenediamine and both inner-sphere and outer-sphere redox probes, namely potassium ferrocyanide(II) and hexaammineruthenium(III) chloride, in addition to the biologically relevant and electroactive analytes, dopamine (DA) and acetaminophen (AP). Comparisons are made with an edge-plane pyrolytic graphite and glassy-carbon electrode and the benefits of carbon black implemented as a modifier for sensors within electrochemistry are explored, as well as the characterisation of their electroanalytical performances. We reveal significant improvements in the electrochemical performance (excellent sensitivity, faster heterogeneous electron transfer rate (HET)) over that of a bare glassy-carbon and edge-plane pyrolytic graphite electrode and thus suggest that there are substantial advantages of using carbon black as modifier in the fabrication of electrochemical based sensors. Such work is highly important and informative for those working in the field of electroanalysis where electrochemistry can provide portable, rapid, reliable and accurate sensing protocols (bringing the laboratory into the field), with particular relevance to those searching for new electrode materials

  7. Corrosion of carbon steel and low-alloy steel in diluted seawater containing hydrazine under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Nakano, Junichi; Yamamoto, Masahiro; Tsukada, Takashi

    2014-01-01

    Seawater was injected into reactor cores of Units 1, 2, and 3 in the Fukushima Daiichi nuclear power station as an urgent coolant. It is considered that the injected seawater causes corrosion of steels of the reactor pressure vessel and primary containment vessel. To investigate the effects of gamma-rays irradiation on weight loss in carbon steel and low-alloy steel, corrosion tests were performed in diluted seawater at 50°C under gamma-rays irradiation. Specimens were irradiated with dose rates of 4.4 kGy/h and 0.2 kGy/h. To evaluate the effects of hydrazine (N 2 H 4 ) on the reduction of oxygen and hydrogen peroxide, N 2 H 4 was added to the diluted seawater. In the diluted seawater without N 2 H 4 , weight loss in the steels irradiated with 0.2 kGy/h was similar to that in the unirradiated steels, and weight loss in the steels irradiated with 4.4 kGy/h increased to approximate 1.7 times of those in the unirradiated steels. Weight loss in the steels irradiated in the diluted seawater containing N 2 H 4 was similar to that in the diluted seawater without N 2 H 4 . When N 2 was introduced into the gas phase in the flasks during gamma-rays irradiation, weight loss in the steels decreased. (author)

  8. Effects of electron irradiation in space environment on thermal and mechanical properties of carbon fiber/bismaleimide composite

    International Nuclear Information System (INIS)

    Yu, Qi; Chen, Ping; Gao, Yu; Ma, Keming; Lu, Chun; Xiong, Xuhai

    2014-01-01

    Highlights: •Electron irradiation decreased the storage modulus finally. •T g decreased first and then increased and finally decreased. •The thermal stability was reduced and then improved and finally decreased. •The changing trend of flexural strength and ILSS are consistent. -- Abstract: The effects of electron irradiation in simulated space environment on thermal and mechanical properties of high performance carbon fiber/bismaleimide composites were investigated. The dynamic mechanical properties of the composites exposed to different fluences of electron irradiation were evaluated by Dynamic mechanical analysis (DMA). Thermogravimetric analysis was applied to investigate the changes in thermal stability of the resin matrix after exposure to electron irradiation. The changes in mechanical properties of the composites were evaluated by flexural strength and interlaminar shear strength (ILSS). The results indicated that electron irradiation in high vacuum had an impact on thermal and mechanical properties of CF/BMI composites, which depends on irradiation fluence. At lower irradiation fluences less than 5 × 10 15 cm −2 , the dynamic storage modulus, cross-linking degree, thermal stability and mechanical properties that were determined by a competing effect between chain scission and cross-linking process, decreased firstly and then increased. While at higher fluences beyond 5 × 10 15 cm −2 , the chain scission process was dominant and thus led to the degradation in thermal and mechanical properties of the composites

  9. Kinetic electron emission from highly oriented pyrolytic graphite surfaces induced by singly charged ions

    CERN Document Server

    Cernusca, S; Winter, H; Aumayr, F; Loerincik, J; Sroubek, Z

    2002-01-01

    We present total electron yields determined by current measurements for normal impact of H sup + , H sub 2 sup + , H sub 3 sup + , C sup + , N sup + and O sup + ions (E<=10 keV) on a clean highly oriented pyrolytic graphite surface. The kinetic energy of the projectiles has been varied from near threshold up to 10 keV. By comparing the results to similar data obtained for a polycrystalline Au surface the role of different target properties for kinetic electron emission can be analysed.

  10. Mechanical properties of irradiated rubber-blends

    International Nuclear Information System (INIS)

    Nasr, G.M.; Madani, M.

    2005-01-01

    A study has been made on blend ratios of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) that are loaded with general purpose furnace (GPE) carbon black and irradiated at different gamma radiation doses. It was fount that the mechanical properties of such blend are highly affected by γ- irradiation dose and the composition ratios of its constituents. The elongation at break for blends was found to increase slightly with increasing NBR loafing which is mainly due to the stiffness of blending matrix formation between NR and GPF carbon black particles. The hysteresis loss, extension ratio and shape factor have been calculated for the different un-irradiated and irradiated samples

  11. Effect of electron injection on defect reactions in irradiated silicon containing boron, carbon, and oxygen

    Science.gov (United States)

    Makarenko, L. F.; Lastovskii, S. B.; Yakushevich, H. S.; Moll, M.; Pintilie, I.

    2018-04-01

    Comparative studies employing Deep Level Transient Spectroscopy and C-V measurements have been performed on recombination-enhanced reactions between defects of interstitial type in boron doped silicon diodes irradiated with alpha-particles. It has been shown that self-interstitial related defects which are immobile even at room temperatures can be activated by very low forward currents at liquid nitrogen temperatures. Their activation is accompanied by the appearance of interstitial carbon atoms. It has been found that at rather high forward current densities which enhance BiOi complex disappearance, a retardation of Ci annealing takes place. Contrary to conventional thermal annealing of the interstitial boron-interstitial oxygen complex, the use of forward current injection helps to recover an essential part of charge carriers removed due to irradiation.

  12. Influence of high-energy electron irradiation on field emission properties of multi-walled carbon nanotubes (MWCNTs) films

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Sandip S. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Koinkar, Pankaj M. [Center for International Cooperation in Engineering Education (CICEE), University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan); Dhole, Sanjay D. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); More, Mahendra A., E-mail: mam@physics.unipune.ac.i [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Murakami, Ri-ichi, E-mail: murakami@me.tokushima-u.ac.j [Department of Mechanical Engineering, University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan)

    2011-04-15

    The effect of very high energy electron beam irradiation on the field emission characteristics of multi-walled carbon nanotubes (MWCNTs) has been investigated. The MWCNTs films deposited on silicon (Si) substrates were irradiated with 6 MeV electron beam at different fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films were characterized using scanning electron microscope (SEM) and micro-Raman spectrometer. The SEM analysis clearly revealed a change in surface morphology of the films upon irradiation. The Raman spectra of the irradiated films show structural damage caused by the interaction of high-energy electrons. The field emission studies were carried out in a planar diode configuration at the base pressure of {approx}1x10{sup -8} mbar. The values of the threshold field, required to draw an emission current density of {approx}1 {mu}A/cm{sup 2}, are found to be {approx}0.52, 1.9, 1.3 and 0.8 V/{mu}m for untreated, irradiated with fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films exhibit better emission current stability as compared to the untreated film. The improved field emission properties of the irradiated films have been attributed to the structural damage as revealed from the Raman studies.

  13. A branching process model for the analysis of abortive colony size distributions in carbon ion-irradiated normal human fibroblasts

    International Nuclear Information System (INIS)

    Sakashita, Tetsuya; Kobayashi, Yasuhiko; Hamada, Nobuyuki; Kawaguchi, Isao; Hara, Takamitsu; Saito, Kimiaki

    2014-01-01

    A single cell can form a colony, and ionizing irradiation has long been known to reduce such a cellular clonogenic potential. Analysis of abortive colonies unable to continue to grow should provide important information on the reproductive cell death (RCD) following irradiation. Our previous analysis with a branching process model showed that the RCD in normal human fibroblasts can persist over 16 generations following irradiation with low linear energy transfer (LET) γ-rays. Here we further set out to evaluate the RCD persistency in abortive colonies arising from normal human fibroblasts exposed to high-LET carbon ions (18.3 MeV/u, 108 keV/μm). We found that the abortive colony size distribution determined by biological experiments follows a linear relationship on the log–log plot, and that the Monte Carlo simulation using the RCD probability estimated from such a linear relationship well simulates the experimentally determined surviving fraction and the relative biological effectiveness (RBE). We identified the short-term phase and long-term phase for the persistent RCD following carbon-ion irradiation, which were similar to those previously identified following γ-irradiation. Taken together, our results suggest that subsequent secondary or tertiary colony formation would be invaluable for understanding the long-lasting RCD. All together, our framework for analysis with a branching process model and a colony formation assay is applicable to determination of cellular responses to low- and high-LET radiation, and suggests that the long-lasting RCD is a pivotal determinant of the surviving fraction and the RBE. (author)

  14. Conformal atomic layer deposition of alumina on millimeter tall, vertically-aligned carbon nanotube arrays.

    Science.gov (United States)

    Stano, Kelly L; Carroll, Murphy; Padbury, Richard; McCord, Marian; Jur, Jesse S; Bradford, Philip D

    2014-11-12

    Atomic layer deposition (ALD) can be used to coat high aspect ratio and high surface area substrates with conformal and precisely controlled thin films. Vertically aligned arrays of multiwalled carbon nanotubes (MWCNTs) with lengths up to 1.5 mm were conformally coated with alumina from base to tip. The nucleation and growth behaviors of Al2O3 ALD precursors on the MWCNTs were studied as a function of CNT surface chemistry. CNT surfaces were modified through a series of post-treatments including pyrolytic carbon deposition, high temperature thermal annealing, and oxygen plasma functionalization. Conformal coatings were achieved where post-treatments resulted in increased defect density as well as the extent of functionalization, as characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. Using thermogravimetric analysis, it was determined that MWCNTs treated with pyrolytic carbon and plasma functionalization prior to ALD coating were more stable to thermal oxidation than pristine ALD coated samples. Functionalized and ALD coated arrays had a compressive modulus more than two times higher than a pristine array coated for the same number of cycles. Cross-sectional energy dispersive X-ray spectroscopy confirmed that Al2O3 could be uniformly deposited through the entire thickness of the vertically aligned MWCNT array by manipulating sample orientation and mounting techniques. Following the ALD coating, the MWCNT arrays demonstrated hydrophilic wetting behavior and also exhibited foam-like recovery following compressive strain.

  15. Combined quantum-mechanics/molecular-mechanics dynamics simulation of A-DNA double strands irradiated by ultra-low-energy carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ngaojampa, C.; Nimmanpipug, P. [Computer Simulation and Modeling Laboratory (CSML), Department of Chemistry and Center for Innovation Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.t [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Lee, V.S., E-mail: vannajan@gmail.co [Computer Simulation and Modeling Laboratory (CSML), Department of Chemistry and Center for Innovation Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2011-02-15

    In order to promote understanding of the fundamentals of ultra-low-energy ion interaction with DNA, molecular dynamics simulations using combined quantum-mechanics/molecular-mechanics of poly-AT and poly-GC A-DNA double strands irradiated by <200 eV carbon ions were performed to investigate the molecular implications of mutation bias. The simulations were focused on the responses of the DNA backbones and nitrogenous bases to irradiation. Analyses of the root mean square displacements of the backbones and non-hydrogen atoms of base rings of the simulated DNA structure after irradiation revealed a potential preference of DNA double strand separation, dependent on the irradiating energy. The results show that for the backbones, the large difference in the displacement between poly-GC and poly-AT in the initial time period could be the reason for the backbone breakage; for the nitrogenous base pairs, A-T is 30% more sensitive or vulnerable to ion irradiation than G-C, demonstrating a preferential, instead of random, effect of irradiation-induced mutation.

  16. Combined quantum-mechanics/molecular-mechanics dynamics simulation of A-DNA double strands irradiated by ultra-low-energy carbon ions

    International Nuclear Information System (INIS)

    Ngaojampa, C.; Nimmanpipug, P.; Yu, L.D.; Anuntalabhochai, S.; Lee, V.S.

    2011-01-01

    In order to promote understanding of the fundamentals of ultra-low-energy ion interaction with DNA, molecular dynamics simulations using combined quantum-mechanics/molecular-mechanics of poly-AT and poly-GC A-DNA double strands irradiated by <200 eV carbon ions were performed to investigate the molecular implications of mutation bias. The simulations were focused on the responses of the DNA backbones and nitrogenous bases to irradiation. Analyses of the root mean square displacements of the backbones and non-hydrogen atoms of base rings of the simulated DNA structure after irradiation revealed a potential preference of DNA double strand separation, dependent on the irradiating energy. The results show that for the backbones, the large difference in the displacement between poly-GC and poly-AT in the initial time period could be the reason for the backbone breakage; for the nitrogenous base pairs, A-T is 30% more sensitive or vulnerable to ion irradiation than G-C, demonstrating a preferential, instead of random, effect of irradiation-induced mutation.

  17. Microstructure and grain size effects on irradiation hardening of low carbon steel for reactor tanks

    International Nuclear Information System (INIS)

    Milasin, N.

    1964-05-01

    Irradiation hardening of steel for reactor pressure vessels has been studied extensively during the past few years. A great number of experimental results concerning the behaviour of these steels in the radiation field and several review papers (1,2) have been published. Most of the papers deal with the effects of specific metallurgical factors or irradiation conditions (temperature, flux) on irradiation hardening and embrittlement. In addition, a number of experiments are performed to give evidence on the mechanism of irradiation hardening of these steels. However, this mechanism is still unknown due to the complexity of steel as a system. Among different methods used in radiation damage studies, the changes of mechanical properties have been mainly investigated. By using Hall-Petch's empirical relation, σ y =σ i +k y d -1/2 between lower yield stress, σ y , and grain size, 2d, the information about the effect of irradiation on the parameters σ i and k y is obtained. Taking as a base interpretation of σ i and k y given by Petch and his co-workers it has been concluded that radiation does not change the stress to start slip but that it increase the friction that opposes the passage of free dislocations across a slip plane. In attempting to apply Hall-Petch's relation to one unirradiated ferritic steel with a carbon content higher than 0.15% some difficulties were encountered. The results obtained indicate that the influence of grain size can not be isolated from other factors introduced by the treatments used to produce different grain sizes. This paper deals with a similar problem in the case of irradiated steel. The results obtained give the changes of the mechanical properties of steel in neutron irradiation field as a function of microstructure and grain size. In addition, the mechanical properties of irradiated steel are measured after annealing at 150 deg C and 450 deg C. On the basis of the experimental results obtained the relative microstructure and

  18. Coating of carbon short fibers with thin ceramic layers by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hackl, Gerrit; Gerhard, Helmut; Popovska, Nadejda

    2006-01-01

    Carbon short fiber bundles with a length of 6 mm were uniformly coated using specially designed, continuous chemical vapor deposition (CVD) equipment. Thin layers of titanium nitride, silicon nitride (SiC) and pyrolytic carbon (pyC) were deposited onto several kilograms of short fibers in this large scale CVD reactor. Thermo-gravimetric analyses and scanning electron microscopy investigations revealed layer thicknesses between 20 and 100 nm on the fibers. Raman spectra of pyC coated fibers show a change of structural order depending on the CVD process parameters. For the fibers coated with SiC, Raman investigations showed a deposition of amorphous SiC. The coated carbon short fibers will be applied as reinforcing material in composites with ceramic and metallic matrices

  19. Carbon Ion irradiation in the treatment of grossly incomplete or unresectable malignant peripheral nerve sheaths tumors: acute toxicity and preliminary outcome

    International Nuclear Information System (INIS)

    Jensen, Alexandra D; Uhl, Matthias; Chaudhri, Naved; Herfarth, Klaus K; Debus, Juergen; Roeder, Falk

    2015-01-01

    To report our early experience with carbon ion irradiation in the treatment of gross residual or unresectable malignant peripheral nerve sheath tumors (MPNST). We retrospectively analysed 11 patients (pts) with MPNST, who have been treated with carbon ion irradiation (C12) at our institution between 2010 and 2013. All pts had measurable gross disease at the initiation of radiation treatment. Median age was 47 years (29-79). Tumors were mainly located in the pelvic/sacral (5 pts) and sinunasal/orbital region (5 pts). 5 pts presented already in recurrent situation, 3 pts had been previously irradiated, and in 3 pts MPNST were neurofibromatosis type 1 (NF1) associated. Median cumulative dose was 60 GyE. Treatment was carried out either as a combination of IMRT plus C12 boost (4 pts) or C12 only (7 pts). Median follow-up was 17 months (3-31 months). We observed 3 local progressions, translating into estimated 1- and 2-year local control rates of 65%. One patient developed distant failure, resulting in estimated 1- and 2-year PFS rates of 56%. Two patients have died, therefore the estimated 1- and 2-year OS rates are 75%. Acute radiation related toxicities were generally mild, no grade 3 side effects were observed. Severe late toxicity (grade 3) was scored in 2 patients (trismus, wound healing delays). Carbon ion irradiation yields very promising short term local control and overall survival rates with low morbidity in patients suffering from gross residual or unresectable malignant peripheral nerve sheath tumors and should be further investigated in a prospective trial

  20. Mouse skin damages caused by fractionated irradiation with carbon ions

    International Nuclear Information System (INIS)

    Ando, K.; Chen, Y.J.; Ohira, C.; Nojima, K.; Ando, S.; Kobayashi, N.; Ohbuchi, T.; Shimizu, W.; Koike, S.; Kanai, T.

    1997-01-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/μm also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/μm in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/μm were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/μ steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  1. Mouse skin damages caused by fractionated irradiation with carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ando, K; Chen, Y J; Ohira, C; Nojima, K; Ando, S; Kobayashi, N; Ohbuchi, T; Shimizu, W [Space and Particle Radiation Science Research Group, Chiba (Japan); Koike, S; Kanai, T [National Inst. of Radiological Sciences, Chiba (Japan). Div. of Accelerator Physics

    1997-09-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/{mu}m also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/{mu}m in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/{mu}m were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/{mu} steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  2. Bystander effect in human hepatoma HepG2 cells caused by medium transfers at different times after high-LET carbon ion irradiation

    International Nuclear Information System (INIS)

    Wu Qingfeng; Li Qiang; Jin Xiaodong; Liu Xinguo; Dai Zhongying

    2011-01-01

    Although radiation-induced bystander effects have been well documented in a variety of biological systems, whether irradiated cells have the ability to generate bystander signaling persistently is still unclear and the clinical relevance of bystander effects in radiotherapy remains to be elucidated. This study examines tumor cellular bystander response to autologous medium from cell culture irradiated with high-linear energy transfer (LET) heavy ions at a therapeutically relevant dose in terms of clonogenic cell survival. In vitro experiments were performed using human hepatoma HepG2 cell line exposed to 100 keV/μm carbon ions at a dose of 2 Gy. Two different periods (2 and 12 h) after irradiation, irradiated cell conditioned medium (ICCM) and replenished fresh medium were harvested and then transferred to unirradiated bystander cells. Cellular bystander responses were measured with the different medium transfer protocols. Significant higher survival fractions of unirradiated cells receiving the media from the irradiated cultures at the different times post-irradiation than those of the control were observed. Even replenishing fresh medium for unirradiated cells which had been exposed to the ICCM for 12 h could not prevent the bystander cells from the increased survival fraction. These results suggest that the irradiated cells could release unidentified signal factor(s), which induced the increase in survival fraction for the unirradiated bystander cells, into the media sustainedly and the carbon ions triggered a cascade of signaling events in the irradiated cells rather than secreting the soluble signal factor(s) just at a short period after irradiation. Based on the observations in this study, the importance of bystander effect in clinical radiotherapy was discussed and incorporating the bystander effect into the current radiobiological models, which are applicable to heavy ion radiotherapy, is needed urgently.

  3. Mutation induced with ion beam irradiation in rose

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H. E-mail: yhiroya@nias.affrc.go.jp; Nagatomi, S.; Morishita, T.; Degi, K.; Tanaka, A.; Shikazono, N.; Hase, Y

    2003-05-01

    The effects of mutation induction by ion beam irradiation on axillary buds in rose were investigated. Axillary buds were irradiated with carbon and helium ion beams, and the solid mutants emerged after irradiation by repeated cutting back. In helium ion irradiation, mutations were observed in plants derived from 9 buds among 56 irradiated buds in 'Orange Rosamini' and in plants derived from 10 buds among 61 irradiated buds in 'Red Minimo'. In carbon ion, mutations were observed in plants derived from 12 buds among 88 irradiated buds in 'Orange Rosamini'. Mutations were induced not only in higher doses but also in lower doses, with which physiological effect by irradiation was hardly observed. Irradiation with both ion beams induced mutants in the number of petals, in flower size, in flower shape and in flower color in each cultivar.

  4. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: Mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Kyung, E-mail: dkim@aum.edu [Department of Physical Science, Auburn University Montgomery, Montgomery, AL 36117 (United States); O' Shea, Kevin E., E-mail: osheak@fiu.edu [Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199 (United States); Cooper, William J. [Department of Civil and Environmental Engineering, Urban Water Research Center, University of California Irvine, Irvine, CA 92697-2175 (United States)

    2012-07-15

    Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from {beta}-H abstraction overlap with those from high temperature pyrolysis, the effect of {beta}-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis. - Highlights: Black-Right-Pointing-Pointer Gasoline oxygenates (ETBE, TAME, DIPE) were completely degraded after 6 hours under ultrasonic irradiation in O{sub 2} saturation. Black-Right-Pointing-Pointer The major degradation pathways were proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals and low temperature pyrolytic degradation. Black-Right-Pointing-Pointer The effect of {beta

  5. Atomic force microscopy study of anion intercalation into highly oriented pyrolytic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Alliata, D; Haering, P; Haas, O; Koetz, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Siegenthaler, H [University of Berne (Switzerland)

    1999-08-01

    In the context of ion transfer batteries, we studied highly oriented pyrolytic graphite (HOPG) in perchloric acid, as a model to elucidate the mechanism of electrochemical intercalation in graphite. Aim of the work is the local and time dependent investigation of dimensional changes of the host material during electrochemical intercalation processes on the nanometer scale. We used atomic force microscopy (AFM), combined with cyclic voltammetry, as in-situ tool of analysis during intercalation and expulsion of perchloric anions into the HOPG electrodes. According to the AFM measurements, the HOPG interlayer spacing increases by 32% when perchloric anions intercalate, in agreement with the formation of stage IV of graphite intercalation compounds. (author) 3 figs., 3 refs.

  6. Deuterium trapping in carbon fiber composites under high fluence

    International Nuclear Information System (INIS)

    Airapetov, A.A.; Begrambekov, L.B.; Kuzmin, A.A.; Shigin, P.A.; Zakharov, A.M.

    2010-01-01

    The paper is devoted to investigation of deuterium trapping in CFC, dance graphite MPG-8 and pyrolytic graphite (PG) under plasma ion- and electron irradiation. Number of specific features of deuterium trapping and retention under plasma ion and electron irradiation is presented and discussed. In particular it is shown that 1) deuterium trapping takes place even when energy of impinging ions approaches zero; 2) deuterium is trapped under irradiation by plasma electrons; 3) under irradiation at equal fluences deuterium trapping is higher, when ion flux is smaller. High energy ion penetrating the surfaces are trapped in the traps created at the expense of their kinetic energy. The process may be named 'kinetic trapping'. Under low energy (smaller than 200 eV) electron and/or ion irradiation the energy of inelastic interaction on the surface provides creation of active centers, which initiate dissociation of deuterium sorbed on the surface, penetration of deuterium atoms into graphite and their trapping in specific low energy traps. The term 'potential trapping' is proposed for this type of trapping. Under high energy irradiation such atoms can fill the traps formed through kinetic mechanism. Origination of moveable deuterium atoms from the layer of surface sorption seems to be time dependent process and it is a reason of increase of trapping along with irradiation time. New features of deuterium trapping and retention in graphite evaluated in this study offer new opportunities for analysis and correct estimation of hydrogen isotope trapping and retention in tokamaks having graphite tiles. (authors)

  7. Development of a Radial Deconsolidation Method

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    A series of experiments have been initiated to determine the retention or mobility of fission products* in AGR fuel compacts [Petti, et al. 2010]. This information is needed to refine fission product transport models. The AGR-3/4 irradiation test involved half-inch-long compacts that each contained twenty designed-to-fail (DTF) particles, with 20-μm thick carbon-coated kernels whose coatings were deliberately fabricated such that they would crack under irradiation, providing a known source of post-irradiation isotopes. The DTF particles in these compacts were axially distributed along the compact centerline so that the diffusion of fission products released from the DTF kernels would be radially symmetric [Hunn, et al. 2012; Hunn et al. 2011; Kercher, et al. 2011; Hunn, et al. 2007]. Compacts containing DTF particles were irradiated at Idaho National Laboratory (INL) at the Advanced Test Reactor (ATR) [Collin, 2015]. Analysis of the diffusion of these various post-irradiation isotopes through the compact requires a method to radially deconsolidate the compacts so that nested-annular volumes may be analyzed for post-irradiation isotope inventory in the compact matrix, TRISO outer pyrolytic carbon (OPyC), and DTF kernels. An effective radial deconsolidation method and apparatus appropriate to this application has been developed and parametrically characterized.

  8. Development of blood irradiators

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This project is designed to improve the techniques of blood irradiation through the development of improved and portable blood irradiators. A portable blood irradiator, consisting of a vitreous carbon body and thulium-170 radiation source, was attached to dogs via a carotid-jugular shunt, and its effects on the immune system measured. The device has demonstrated both significant suppression of circulating lymphocytes and prolonged retention of skin allografts

  9. Characterization of a polychromatic neutron beam diffracted by pyrolytic graphite crystals

    CERN Document Server

    Byun, S H; Choi, H D

    2002-01-01

    The beam spectrum for polychromatic neutrons diffracted by pyrolytic graphite crystals was characterized. The theoretical beam spectrum was obtained using the diffraction model for a mosaic crystal. The lattice vibration effects were included in the calculation using the reported vibration amplitude of the crystal and the measured time-of-flight spectra in the thermal region. The calculated beam spectrum was compared with the results obtained in the absence of thermal motion. The lattice vibration effects became more important for the higher diffraction orders and a large decrease in the neutron flux induced by the vibrations was identified in the epithermal region. The validity of the beam spectrum was estimated by comparing with the effective quantities determined from prompt gamma-ray measurements and Cd-ratios measured both for 1/nu and non-1/nu nuclides.

  10. Clonogenic cell line survival of a human liver cancer cell line SMMC-7721 after carbon ion irradiation with different LET

    International Nuclear Information System (INIS)

    Lei Suwen; Su Xu; Wang Jifang; Li Wenjian

    2003-01-01

    Objective: To investigate the survival fraction of a human liver cancer cell line SMMC-7721 following irradiation with carbon ions with different LET. Methods: cells of the human liver cancer cell line SMMC-7721 were irradiated with carbon ions (LET=30 and 70 keV/μm). The survival fraction was determined with clonogenic assay after 9 days incubation in a 5% CO 2 incubator at 37 degree C. Results: When the survival fractions of 70 keV/μm were D s = 0.1 and D s=0.01 absorption dose were 2.94 and 5.88 Gy respectively, and those of 30 keV/μm were 4.00 and 8.00 Gy respectively. Conclusion: For the SMMC-7721 cell line, 70 keV/μm is more effective for cell killing than 30 keV/μm

  11. Graphite targets at LAMPF

    International Nuclear Information System (INIS)

    Brown, R.D.; Grisham, D.L.

    1983-01-01

    Rotating polycrystalline and stationary pyrolytic graphite target designs for the LAMPF experimental area are described. Examples of finite element calculations of temperatures and stresses are presented. Some results of a metallographic investigation of irradiated pyrolytic graphite target plates are included, together with a brief description of high temperature bearings for the rotating targets

  12. Characteristics of Pyrolytic Graphite as a Neutron Monochromator

    International Nuclear Information System (INIS)

    Adib, M.; Habib, N.; El-Mesiry, M.S.; Fathallah, M.

    2011-01-01

    Pyrolytic graphite (PG) has become nearly indispensable in neutron spectroscopy. Since the integrated reflectivity of the monochromatic neutrons from PG crystals cut along its c-axis is high within a wavelength band from 0.1 nm up to .65 nm. The monochromatic features of PG crystal is detailed in terms of the optimum mosaic spread, crystal thickness and reactor moderating temperature for efficient integrated neutron reflectivity within the wavelength band. A computer code Mono-PG has been developed to carry out the required calculations for the PG hexagonal close-packed structure. Calculation shows that, 2 mm thick of PG crystal having 0.30 FWHM on mosaic spread are the optimum parameters of PG crystal as a monochromator at selected neutron wavelength shorter than 2 nm. However, the integrated neutron intensity of 2nd and 3rd orders from thermal reactor flux is even higher than that of the 1st order one at neutron wavelengths longer than 2 nm. While, from cold reactor flux, integrated neutron intensity of the 1st order within the wavelength band from 0.25 up to 0.5 nm is higher than the 2nd and 3rd ones

  13. Multifractal characterization of single wall carbon nanotube thin films surface upon exposure to optical parametric oscillator laser irradiation

    International Nuclear Information System (INIS)

    Ţălu, Ştefan; Marković, Zoran; Stach, Sebastian; Todorović Marković, B.; Ţălu, Mihai

    2014-01-01

    This study presents a multifractal approach, obtained with atomic force microscopy analysis, to characterize the structural evolution of single wall carbon nanotube thin films upon exposure to optical parametric oscillator laser irradiation at wavelength of 430 nm. Microstructure and morphological changes of carbon nanotube films deposited on different substrates (mica and TGX grating) were recorded by atomic force microscope. A detailed methodology for surface multifractal characterization, which may be applied for atomic force microscopy data, was presented. Multifractal analysis of surface roughness revealed that carbon nanotube films surface has a multifractal geometry at various magnifications. The generalized dimension D q and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of carbon nanotube films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

  14. Microstructure and grain size effects on irradiation hardening of low carbon steel for reactor tanks

    Energy Technology Data Exchange (ETDEWEB)

    Milasin, N [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1964-05-15

    Irradiation hardening of steel for reactor pressure vessels has been studied extensively during the past few years. A great number of experimental results concerning the behaviour of these steels in the radiation field and several review papers (1,2) have been published. Most of the papers deal with the effects of specific metallurgical factors or irradiation conditions (temperature, flux) on irradiation hardening and embrittlement. In addition, a number of experiments are performed to give evidence on the mechanism of irradiation hardening of these steels. However, this mechanism is still unknown due to the complexity of steel as a system. Among different methods used in radiation damage studies, the changes of mechanical properties have been mainly investigated. By using Hall-Petch's empirical relation, {sigma}{sub y}={sigma}{sub i}+k{sub y} d{sup -1/2} between lower yield stress, {sigma}{sub y}, and grain size, 2d, the information about the effect of irradiation on the parameters {sigma}{sub i} and k{sub y} is obtained. Taking as a base interpretation of {sigma}{sub i} and k{sub y} given by Petch and his co-workers it has been concluded that radiation does not change the stress to start slip but that it increase the friction that opposes the passage of free dislocations across a slip plane. In attempting to apply Hall-Petch's relation to one unirradiated ferritic steel with a carbon content higher than 0.15% some difficulties were encountered. The results obtained indicate that the influence of grain size can not be isolated from other factors introduced by the treatments used to produce different grain sizes. This paper deals with a similar problem in the case of irradiated steel. The results obtained give the changes of the mechanical properties of steel in neutron irradiation field as a function of microstructure and grain size. In addition, the mechanical properties of irradiated steel are measured after annealing at 150 deg C and 450 deg C. On the basis of

  15. Diffusion, Thermal Properties and Chemical Compatibilities of Select MAX Phases with Materials For Advanced Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Barsoum, Michel [Drexel Univ., Philadelphia, PA (United States); Bentzel, Grady [Drexel Univ., Philadelphia, PA (United States); Tallman, Darin J. [Drexel Univ., Philadelphia, PA (United States); Sindelar, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, Brenda [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hoffman, Elizabeth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-04

    The demands of Gen IV nuclear power plants for long service life under neutron irradiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ ºC) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the chemical compatibility of select MAX with potential materials that are important for nuclear energy, as well as to measure the thermal transport properties as a function of neutron irradiation. The chemical counterparts chosen for this work are: pyrolytic carbon, SiC, U, Pd, FLiBe, Pb-Bi and Na, the latter 3 in the molten state. The thermal conductivities and heat capacities of non-irradiated MAX phases will be measured.

  16. Carbon Contamination During Ion Irradiation - Accurate Detection and Characterization of its Effect on Microstructure of Ferritic/Martensitic Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Toloczko, Mychailo B.; Kruska, Karen; Schreiber, Daniel K.; Edwards, Danny J.; Zhu, Zihua; Zhang, Jiandong

    2017-11-17

    Accelerator-based ion beam techniques have been used to study radiation effects in materials for decades. Although carbon contamination induced by ion beam in target materials is a well-known issue, it has not been fully characterized nor quantified for studies in ferritic/martensitic (F/M) steels that are candidate materials for applications such as core structural components in advanced nuclear reactors. It is an especially important issue for this class of material because of the effect of carbon level on precipitate formation. In this paper, the ability to quantify carbon contamination using three common techniques, namely time-of-flight secondary ion mass spectroscopy (ToF-SIMS), atom probe tomography (APT) and transmission electron microscopy (TEM) is compared. Their effectiveness and short-comings in determining carbon contamination will be presented and discussed. The corresponding microstructural changes related to carbon contamination in ion irradiated F/M steels are also presented and briefly discussed.

  17. Development of a Scanning Microscale Fast Neutron Irradiation Platform for Examining the Correlation Between Local Neutron Damage and Graphite Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Pinhero, Patrick [Univ. of Missouri, Columbia, MO (United States); Windes, William [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-10

    The fast particle radiation damage effect of graphite, a main material in current and future nuclear reactors, has significant influence on the utilization of this material in fission and fusion plants. Atoms on graphite crystals can be easily replaced or dislocated by fast protons and result in interstitials and vacancies. The currently accepted model indicates that after most of the interstitials recombine with vacancies, surviving interstitials form clusters and furthermore gather to create loops with each other between layers. Meanwhile, surviving vacancies and interstitials form dislocation loops on the layers. The growth of these inserted layers cause the dimensional increase, i.e. swelling, of graphite. Interstitial and vacancy dislocation loops have been reported and they can easily been observed by electron microscope. However, observation of the intermediate atom clusters becomes is paramount in helping prove this model. We utilize fast protons generated from the University of Missouri Research Reactor (MURR) cyclotron to irradiate highly- oriented pyrolytic graphite (HOPG) as target for this research. Post-irradiation examination (PIE) of dosed targets with high-resolution transmission electron microscopy (HRTEM) has permit observation and analysis of clusters and dislocation loops to support the proposed theory. Another part of the research is to validate M.I. Heggie’s Ruck and Tuck model, which introduced graphite layers may fold under fast particle irradiation. Again, we employed microscopy to image irradiated specimens to determine how the extent of Ruck and Tuck by calculating the number of folds as a function of dose. Our most significant accomplishment is the invention of a novel class of high-intensity pure beta-emitters for long-term lightweight batteries. We have filed four invention disclosure records based on the research conducted in this project. These batteries are lightweight because they consist of carbon and tritium and can be

  18. Expression profiles are different in carbon ion-irradiated normal human fibroblasts and their bystander cells

    International Nuclear Information System (INIS)

    Iwakawa, Mayumi; Hamada, Nobuyuki; Imadome, Kaori; Funayama, Tomoo; Sakashita, Testuya; Kobayashi, Yasuhiko; Imai, Takashi

    2008-01-01

    Evidence has accumulated that ionizing radiation induces biological effects in non-irradiated bystander cells having received signals from directly irradiated cells; however, energetic heavy ion-induced bystander response is incompletely characterized. Here we performed microarray analysis of irradiated and bystander fibroblasts in confluent cultures. To see the effects in bystander cells, each of 1, 5 and 25 sites was targeted with 10 particles of carbon ions (18.3 MeV/u, 103 keV/μm) using microbeams, where particles traversed 0.00026, 0.0013 and 0.0066% of cells, respectively. diated cells, cultures were exposed to 10% survival dose (D), 0.1D and 0.01D of corresponding broadbeams (108 keV/μm). Irrespective of the target numbers (1, 5 or 25 sites) and the time (2 or 6 h postirradiation), similar expression changes were observed in bystander cells. Among 874 probes that showed more than 1.5-fold changes in bystander cells, 25% were upregulated and the remainder downregulated. These included genes related to cell communication (PIK3C2A, GNA13, FN1, ANXA1 and IL1RAP), stress response (RAD23B, ATF4 and EIF2AK4) and cell cycle (MYCN, RBBP4 and NEUROG1). Pathway analysis revealed serial bystander activation of G protein/PI-3 kinase pathways. Instead, genes related to cell cycle or death (CDKN1A, GADD45A, NOTCH1 and BCL2L1), and cell communication (IL1B, TCF7 and ID1) were upregulated in irradiated cells, but not in bystander cells. Our results indicate different expression profiles in irradiated and bystander cells, and imply that intercellular signaling between irradiated and bystander cells activate intracellular signaling, leading to the transcriptional stress response in bystander cells

  19. Effect of gamma irradiation on sulfur-cured chlorobutyl rubber

    International Nuclear Information System (INIS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth E.L.; Ono, Lilian S.; Lugao, Ademar B.

    2011-01-01

    Chlorobutyl rubber (CIIR) is similarly manufactured to butyl rubber (IIR). The insertion of chlorine atom in isoprene group represents an improvement in its properties, such as: high vulcanizing speed, low permanent stress and compatibility with other types of rubber. The presence of reactive chlorine in butyl chlorate allows a variety of vulcanizing techniques, being the cure via sulfur, the most conventional. In these compounds carbon-halogen bonds are weaker than carbon-carbon and carbon-hydrogen bonds, and the main effect of radiation is to break the carbon-halogen bond to give an organic free radical. Irradiations of certain alkyl chlorides can bring about isomerism in which the location of the halogen atom is changed, the carbon skeleton of molecule remaining unaltered. Irradiation of n-butyl chlorides gives high yields of tertiary carbon. The major effect of high energy photon, such as gamma rays, in organic polymers is the generation of free radicals, along changes in mechanical properties. This work aims to the study of irradiation effect on mechanical properties of a sulfur cured chlorobutyl rubber compound, gamma irradiated within 25, 50, 100, 150 e 200 kGy doses range. The techniques used in their characterization were: strength - stress analysis and elasticity modulus. Results obtained were investigated, demonstrated and discussed. (author)

  20. Effect of gamma irradiation on sulfur-cured chlorobutyl rubber

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elisabeth E.L.; Ono, Lilian S.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Chlorobutyl rubber (CIIR) is similarly manufactured to butyl rubber (IIR). The insertion of chlorine atom in isoprene group represents an improvement in its properties, such as: high vulcanizing speed, low permanent stress and compatibility with other types of rubber. The presence of reactive chlorine in butyl chlorate allows a variety of vulcanizing techniques, being the cure via sulfur, the most conventional. In these compounds carbon-halogen bonds are weaker than carbon-carbon and carbon-hydrogen bonds, and the main effect of radiation is to break the carbon-halogen bond to give an organic free radical. Irradiations of certain alkyl chlorides can bring about isomerism in which the location of the halogen atom is changed, the carbon skeleton of molecule remaining unaltered. Irradiation of n-butyl chlorides gives high yields of tertiary carbon. The major effect of high energy photon, such as gamma rays, in organic polymers is the generation of free radicals, along changes in mechanical properties. This work aims to the study of irradiation effect on mechanical properties of a sulfur cured chlorobutyl rubber compound, gamma irradiated within 25, 50, 100, 150 e 200 kGy doses range. The techniques used in their characterization were: strength - stress analysis and elasticity modulus. Results obtained were investigated, demonstrated and discussed. (author)

  1. Pyrolytic Graphite as a Tunable Second order Neutron Filter

    International Nuclear Information System (INIS)

    Adib, M.

    2009-01-01

    A study has been carried out on the neutron transmission through pyrolytic graphite (PG) crystals in order to check its applicability as an efficient tunable second order neutron filter. The neutron transmission have been calculated as a function of neutron wavelengths in the range from 0.01 nm up to 0.7 nm at various PG mosaic spread, thickness and orientation of its c-axis with respect to the beam direction The Computer package Graphite has been used to provide the required calculation. It was shown that highly aligned (10 FWHM on mosaic spread) PG crystal ∼2 cm thick, may be tuned for optimum scattering of 2 second order neutrons within some favorable wavelength intervals in the range between 0.112 and 0.425 nm by adjusting the crystal in an appropriate orientation. .However, a less quality and thinner PG was found to almost eliminate 2 second order neutrons at only tuned values of wavelength corresponding to the poison of the triple intersection points of the curves (hkl) ± and (00l)

  2. Clinical Impact of Re-irradiation with Carbon-ion Radiotherapy for Lymph Node Recurrence of Gynecological Cancers.

    Science.gov (United States)

    Shiba, Shintaro; Okonogi, Noriyuki; Kato, Shingo; Wakatsuki, Masaru; Kobayashi, Daijiro; Kiyohara, Hiroki; Ohno, Tatsuya; Karasawa, Kumiko; Nakano, Takashi; Kamada, Tadashi

    2017-10-01

    To evaluate the safety and efficacy of re-irradiation with carbon-ion radiotherapy (C-ion RT) for lymph node recurrence of gynecological cancers after definitive radiotherapy. Data regarding patients with unresectable and isolated recurrent lymph node from gynecological cancer after definitive radiotherapy were analyzed. Total dose of C-ion RT was 48-57.6 Gy (RBE) in 12 or 16 fractions. Sixteen patients received re-irradiation by C-ion RT were analyzed. Median follow-up was 37 months. Median tumor size was 27 mm. None developed Grade 1 or higher acute toxicities and Grade 3 or higher late toxicities. The 3-year overall survival, local control and disease-free survival rates after C-ion RT were 74%, 94% and 55%, respectively. Re-irradiation with C-ion RT for lymph node recurrence of gynecological cancers after definitive radiotherapy can be safe and effective. This result suggested that C-ion RT could be a curative treatment option for conventionally difficult-to-cure patients. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  3. Evaluation of KTJT-1, an early-maturity of sweet sorghum acquired by carbon ions irradiation

    International Nuclear Information System (INIS)

    Dong Xicun; Li Wenjian

    2014-01-01

    Sweet sorghum has the potential of becoming a useful energy crop. An early-maturity mutant of sweet sorghum, KFJT-1, was obtained by carbon ions irradiation of KFJT-CK, a wild plant. In this paper, we evaluate the mutant from the length and fresh weight of radicle and leaves after seed germination, the growth rate at the elongation stage, and the internodal parameters under field trail condition. The results showed that the seedling growth of KFJT-1 was inhibited by carbon ions irradiation, and the leaf length, the fresh weight of radicle and leaves from KFJT-1 decreased by 15.32%, 76.27%, and 27.08% than those of KFJT-CK, respectively. However, the growth rate of KFJT-1 on July 12, July 27 and August 1 increased by 16.19%, 59.28% and 26.87%, respectively, compared with the KFJT-CK. The stalk diameter, total biomass yield and sugar content of KFJT-1 was higher than those of KFJT-CK, despite that the plant height of KFJT-1 was significantly less than KFJT-CK (P<0.05). In addition, KFJT-1 differed from KFJT-CK in the internodal length, weight and sugar content. In conclusion, the early-maturity mutant of KFJT-1 will be a promising variety for sweet sorghum industrialization in Gansu province, China. (authors)

  4. Carbon-Ion Irradiation Suppresses Migration and Invasiveness of Human Pancreatic Carcinoma Cells MIAPaCa-2 via Rac1 and RhoA Degradation

    International Nuclear Information System (INIS)

    Fujita, Mayumi; Imadome, Kaori; Shoji, Yoshimi; Isozaki, Tetsurou; Endo, Satoshi; Yamada, Shigeru; Imai, Takashi

    2015-01-01

    Purpose: To investigate the mechanisms underlying the inhibition of cancer cell migration and invasion by carbon (C)-ion irradiation. Methods and Materials: Human pancreatic cancer cells MIAPaCa-2, AsPC-1, and BxPC-3 were treated by x-ray (4 Gy) or C-ion (0.5, 1, 2, or 4 Gy) irradiation, and their migration and invasion were assessed 2 days later. The levels of guanosine triphosphate (GTP)-bound Rac1 and RhoA were determined by the active GTPase pull-down assay with or without a proteasome inhibitor, and the binding of E3 ubiquitin ligase to GTP-bound Rac1 was examined by immunoprecipitation. Results: Carbon-ion irradiation reduced the levels of GTP-bound Rac1 and RhoA, 2 major regulators of cell motility, in MIAPaCa-2 cells and GTP-bound Rac1 in AsPC-1 and BxPC-3 cells. Proteasome inhibition reversed the effect, indicating that C-ion irradiation induced Rac1 and RhoA degradation via the ubiquitin (Ub)-proteasome pathway. E3 Ub ligase X-linked inhibitor of apoptosis protein (XIAP), which directly targets Rac1, was selectively induced in C-ion–irradiated MIAPaCa-2 cells and coprecipitated with GTP-bound Rac1 in C-ion–irradiated cells, which was associated with Rac1 ubiquitination. Cell migration and invasion reduced by C-ion radiation were restored by short interfering RNA–mediated XIAP knockdown, indicating that XIAP is involved in C-ion–induced inhibition of cell motility. Conclusion: In contrast to x-ray irradiation, C-ion treatment inhibited the activity of Rac1 and RhoA in MIAPaCa-2 cells and Rac1 in AsPC-1 and BxPC-3 cells via Ub-mediated proteasomal degradation, thereby blocking the motility of these pancreatic cancer cells

  5. Carbon-Ion Irradiation Suppresses Migration and Invasiveness of Human Pancreatic Carcinoma Cells MIAPaCa-2 via Rac1 and RhoA Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Mayumi; Imadome, Kaori; Shoji, Yoshimi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Isozaki, Tetsurou; Endo, Satoshi; Yamada, Shigeru [Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Imai, Takashi, E-mail: imait@nirs.go.jp [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)

    2015-09-01

    Purpose: To investigate the mechanisms underlying the inhibition of cancer cell migration and invasion by carbon (C)-ion irradiation. Methods and Materials: Human pancreatic cancer cells MIAPaCa-2, AsPC-1, and BxPC-3 were treated by x-ray (4 Gy) or C-ion (0.5, 1, 2, or 4 Gy) irradiation, and their migration and invasion were assessed 2 days later. The levels of guanosine triphosphate (GTP)-bound Rac1 and RhoA were determined by the active GTPase pull-down assay with or without a proteasome inhibitor, and the binding of E3 ubiquitin ligase to GTP-bound Rac1 was examined by immunoprecipitation. Results: Carbon-ion irradiation reduced the levels of GTP-bound Rac1 and RhoA, 2 major regulators of cell motility, in MIAPaCa-2 cells and GTP-bound Rac1 in AsPC-1 and BxPC-3 cells. Proteasome inhibition reversed the effect, indicating that C-ion irradiation induced Rac1 and RhoA degradation via the ubiquitin (Ub)-proteasome pathway. E3 Ub ligase X-linked inhibitor of apoptosis protein (XIAP), which directly targets Rac1, was selectively induced in C-ion–irradiated MIAPaCa-2 cells and coprecipitated with GTP-bound Rac1 in C-ion–irradiated cells, which was associated with Rac1 ubiquitination. Cell migration and invasion reduced by C-ion radiation were restored by short interfering RNA–mediated XIAP knockdown, indicating that XIAP is involved in C-ion–induced inhibition of cell motility. Conclusion: In contrast to x-ray irradiation, C-ion treatment inhibited the activity of Rac1 and RhoA in MIAPaCa-2 cells and Rac1 in AsPC-1 and BxPC-3 cells via Ub-mediated proteasomal degradation, thereby blocking the motility of these pancreatic cancer cells.

  6. Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons

    International Nuclear Information System (INIS)

    Raisbeck, G.M.; Lestringuez, J.; Yiou, F.

    1975-01-01

    Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons were measured by mass spectrometry. The results are compared with lower energy measurements and discussed in terms of the variation of the cosmic ray L/M ratio in this energy region [fr

  7. Acceptance Test Data for BWXT Coated Particle Batch 93164A Defective IPyC Fraction and Pyrocarbon Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, John A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-02-01

    Coated particle fuel batch J52O-16-93164 was produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR), or may be used as demonstration production-scale coated particle fuel for other experiments. The tristructural-isotropic (TRISO) coatings were deposited in a 150-mm-diameter production-scale fluidizedbed chemical vapor deposition (CVD) furnace onto 425-μm-nominal-diameter spherical kernels from BWXT lot J52L-16-69316. Each kernel contained a mixture of 15.5%-enriched uranium carbide and uranium oxide (UCO) and was coated with four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. The TRISO-coated particle batch was sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batch was designated by appending the letter A to the end of the batch number (i.e., 93164A).

  8. Acceptance Test Data for Candidate AGR-5/6/7 TRISO Particle Batches BWXT Coater Batches 93165 93172 Defective IPyC Fraction and Pyrocarbon Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, John A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schumacher, Austin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    Coated particle fuel batches J52O-16-93165, 93166, 93168, 93169, 93170, and 93172 were produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR). Some of these batches may alternately be used as demonstration coated particle fuel for other experiments. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT lot J52R-16-69317 containing a mixture of 15.5%-enriched uranium carbide and uranium oxide (UCO). The TRISO coatings consisted of four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μmnominal thickness. The TRISO-coated particle batches were sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batches were designated by appending the letter A to the end of the batch number (e.g., 93165A).

  9. Preparation of Impervious Pyrolytic Carbon Coatings and Application to Dispersed Fuels; Preparation de revetements de carbone pyrolytique etanches - applications aux combustibles disperses; Prigotovlenie nepronitsaemogo uglerodnogo piroliticheskogo pokrytiya dlya dispergirovannogo topliva; Preparacion de revestimientos estancos de carbono piroutico: aplicacion a los combustibles nucleares dispersos

    Energy Technology Data Exchange (ETDEWEB)

    Auriol, A.; David, C. [Battelle Memorial Institute, Geneve (Switzerland); Fillatre, A.; Kurka, G.; Le Boulbin, E.; Rappeneau, J. [Commissariat a l' Energie Atomique (France)

    1963-11-15

    A method of depositing pyrolytic carbon, which adheres well to a graphite support and is gas-tight, was developed and the physical properties of the deposit were evaluated. The fluidized bed technique was used in applying this method of coating to fissile granules of uranium oxide and uranium carbide. After explaining the conditions for coating the granules, the authors examined their macrostructure, microstructure and permeability. Their behaviour at high temperature was investigated with a view to using them in a reactor. (author) [French] Une methode de deposition de carbone pyrolydque adherant bien au graphite support et etanche aux gaz a ete mise au point. Les proprietes physiques du depot ont ete evaluees. Cette methode de revetement a ete transposee a des granules fissiles d'oxyde et de carbure d'uranium en utilisant la technique du lit fluidise. Apres avoir precise les conditions de revetement de ces granules, on etudie leur macrostructure, leur microstructure, ainsi que leur permeabilite. Le comportement de ces granules a haute temperature a ete examine en vue de leur utilisation eventuelle dans un reacteur. (author) [Spanish] Los autores han elaborado un metodo para depositar carbono pirolitico que se adhiere fuertemente al soporte de grafito y es estanco a los gases. Han determinado las propiedades de dicho deposito. Este metodo de revestimiento fue aplicado a granulos fisionables de oxido y de carburo de uranio, utilizando la tecnica del lecho fluidificado. Despues de determinar las condiciones en que se efectua el revestimiento de esos granulos, los autores estudiaron su macroestructura y su microestructura, asi como su permeabilidad. Examinaron tambien su comportamiento a temperatura elevada, con miras a utilizarlos oportunamente en los reactores. (author) [Russian] Razrabotan metod osazhdeniya piroliticheskogo ugleroda, khorosho pokryvayushchego grafitovuyu osnovu s polucheniem nepronitsaemogo dlya gazov pokrytiya. Otseneny fizicheskie svojstva

  10. Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons

    International Nuclear Information System (INIS)

    Raisbeck, G.M.; Lestringuez, J.; Yiou, F.

    1975-01-01

    Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons have been measured by mass spectrometry. The results are compared with lower energy measurements and discussed in terms of the variation of the cosmic ray L/M ratio in the energy region [fr

  11. New pyrolytic and spectroscopic data on Orgueil and Murchison insoluble organic matter: A different origin than soluble?

    Science.gov (United States)

    Remusat, Laurent; Derenne, Sylvie; Robert, François; Knicker, Heike

    2005-08-01

    Pyrolysis with and without tetramethylammonium hydroxide (TMAH), vacuum pyrolysis, and solid state 15N nuclear magnetic resonance (NMR) were used to examine the macromolecular insoluble organic matter (IOM) from the Orgueil and Murchison meteorites. Conventional pyrolysis reveals a set of poorly functionalized aromatic compounds, ranging from one to four rings and with random methyl substitutions. These compounds are in agreement with spectroscopic and pyrolytic results previously reported. For the first time, TMAH thermochemolysis was used to study extraterrestrial material. The detection of aromatics bearing methyl esters and methoxy groups reveals the occurrence of ester and ether bridges between aromatic units in the macromolecular network. No nitrogen-containing compounds were detected with TMAH thermochemolysis, although they are a common feature in terrestrial samples. Along with vacuum pyrolysis results, thermochemolysis shows that nitrogen is probably sequestered in condensed structures like heterocyclic aromatic rings, unlike oxygen, which is mainly located within linkages between aromatic units. This is confirmed by solid state 15N NMR performed on IOM from Orgueil, showing that nitrogen is present in pyrrole, indole, and carbazole moieties. These data show that amino acids are neither derived from the hydrolysis of IOM nor from a common precursor. In order to reconcile the literature isotopic data and the present molecular results, it is proposed that aldehydes and ketones (1) originated during irradiation of ice in space and (2) were then mobilized during the planetesimal hydrothermalism, yielding the formation of amino acids. If correct, prebiotic molecules are the products of the subsurface chemistry of planetesimals and are thus undetectable through astronomical probes.

  12. Using sewage sludge pyrolytic gas to modify titanium alloy to obtain high-performance anodes in bio-electrochemical systems

    Science.gov (United States)

    Gu, Yuan; Ying, Kang; Shen, Dongsheng; Huang, Lijie; Ying, Xianbin; Huang, Haoqian; Cheng, Kun; Chen, Jiazheng; Zhou, Yuyang; Chen, Ting; Feng, Huajun

    2017-12-01

    Titanium is under consideration as a potential stable bio-anode because of its high conductivity, suitable mechanical properties, and electrochemical inertness in the operating potential window of bio-electrochemical systems; however, its application is limited by its poor electron-transfer capacity with electroactive bacteria and weak ability to form biofilms on its hydrophobic surface. This study reports an effective and low-cost way to convert a hydrophobic titanium alloy surface into a hydrophilic surface that can be used as a bio-electrode with higher electron-transfer rates. Pyrolytic gas of sewage sludge is used to modify the titanium alloy. The current generation, anodic biofilm formation surface, and hydrophobicity are systematically investigated by comparing bare electrodes with three modified electrodes. Maximum current density (15.80 A/m2), achieved using a modified electrode, is 316-fold higher than that of the bare titanium alloy electrode (0.05 A/m2) and that achieved by titanium alloy electrodes modified by other methods (12.70 A/m2). The pyrolytic gas-modified titanium alloy electrode can be used as a high-performance and scalable bio-anode for bio-electrochemical systems because of its high electron-transfer rates, hydrophilic nature, and ability to achieve high current density.

  13. Advanced stabilization of PAN fibers for fabrication of carbon fibers by e-beam irradiation

    International Nuclear Information System (INIS)

    Jeun, Joon Pyo; Kim, Du Young; Shin, Hye Kyoung; Kang, Phil Hyun; Park, Jung Ki

    2012-01-01

    In recent years, the carbon fiber industry has been growing rapidly to meet the demand from efferent industries such as aerospace, military, turbine blades, light weight cylinders and pressure vessels. Generally, carbon fibers are manufactured by a controlled pyrolysis of stabilized precursor fiber such as polyacrylonitrile (PAN). In the stabilization step, the linear PAN molecules are first converted to cyclic structure. However, cyclization is a very complicated process and there are still differences of opinion on the reaction mechanisms. Photo-induced crosslinking and stabilization of PAN via ion beam, X-ray, gamma ray and UV irradiation has been reported in the literature. However, the process required a long stabilization time. In this work, a new and highly effective method of pretreatment PAN precursor fiber was described. The effect of the e-beam on the stabilization process of the fibers was investigated using differential scanning calorimeter (DSC) and X-ray diffraction (XRD) measurement

  14. Effects of tube diameter and chirality on the stability of single-walled carbon nanotubes under ion irradiation

    International Nuclear Information System (INIS)

    Xu Zijian; Zhang Wei; Zhu Zhiyuan; Ren Cuilan; Li Yong; Huai Ping

    2009-01-01

    Using molecular dynamics method, we investigated the influence of tube diameter and chirality on the stability of single-walled carbon nanotubes (CNTs) under ion irradiation. We found that in the energy range below 1 keV, the dependence of CNT stability on the tube diameter is no longer monotonic under C ion irradiation, and the thinner (5, 5) CNT may be more stable than the thicker (7, 7) CNT, while under Ar irradiation, the CNT stability increases still monotonically with the CNT diameter. This stability behavior was further verified by the calculations of the threshold ion energies to produce displacement damage in CNTs. The abnormal stability of thin CNTs is related to their resistance to the instantaneous deformation in the wall induced by ion pushing, the high self-healing capacity, as well as the different interaction properties of C and Ar ions with CNT atoms. We also found that under ion irradiation the stability of a zigzag CNT is better than that of an armchair CNT with the same diameter. This is because of the bonding structure difference between the armchair and the zigzag CNTs with respect to the orientations of graphitic networks as well as the self-healing capacity difference.

  15. Post-irradiation examination of a fuel pin using a microscopic X-ray system: Measurement of carbon deposition and pin metrology

    International Nuclear Information System (INIS)

    Gras, Ch.; Stanley, S.J.

    2008-01-01

    The paper presents some interesting aspects associated with X-ray imaging and its potential application in the nuclear industry. The feasibility of using X-ray technology for the post-irradiation examination of a fuel pin has been explored, more specifically pin metrology and carbon deposition measurement. The non-active sample was specially designed to mimic the structure of an AGR fuel pin whilst a carbon based material was applied to the mock up fuel rod in order to mimic carbon deposition. Short duration low energy (50 kV) 2D digital radiography was employed and provided encouraging results (with respect to carbon deposition thickness and structure measurements) for the mock up fuel pin with a spatial resolution of around 10 μm. Obtaining quantitative data from the resultant images is the principal added value associated with X-ray imaging. A higher intensity X-ray beam (≥90 kV) was also used in conjunction with the low energy set-up to produce a clear picture of the cladding as well as the interface between the lead (Pb mimics the uranium oxide) and stainless steel cladding. Spent fuel metrology and routine radiography are two additional tasks that X-ray imaging could perform for the post-irradiation examination programme. Therefore, when compared to other techniques developed to deliver information on one particular parameter, X-ray imaging offers the possibility to extract useful information on a range of parameters

  16. Synthesis of metal free ultrathin graphitic carbon nitride sheet for photocatalytic dye degradation of Rhodamine B under visible light irradiation

    Science.gov (United States)

    Rahman, Shakeelur; Momin, Bilal; Higgins M., W.; Annapure, Uday S.; Jha, Neetu

    2018-04-01

    In recent times, low cost and metal free photocatalyts driven under visible light have attracted a lot of interest. One such photo catalyst researched extensively is bulk graphitic carbon nitride sheets. But the low surface area and weak mobility of photo generated electrons limits its photocatalytic performance in the visible light spectrum. Here we present the facile synthesis of ultrathin graphitic carbon nitride using a cost effective melamine precursor and its application in highly efficient photocatalytic dye degradation of Rhodamine B molecules. Compared to bulk graphitic carbon nitride, the synthesized ultrathin graphitic carbon nitride shows an increase in surface area, a a decrease in optical band gap and effective photogenerated charge separation which facilitates the harvest of visible light irradiation. Due to these optimal properties of ultrathin graphitic carbon nitride, it shows excellent photocatalytic activity with photocatalytic degradation of about 95% rhodamine B molecules in 1 hour.

  17. Mechanical behavior of styrene grafted PVC films by electron beam irradiation

    International Nuclear Information System (INIS)

    Cardoso, Jessica R.; Moura, Eduardo; Somessari, Elisabeth S.R.; Silveira, Carlos G.; Paes, Helio A.; Souza, Carlos A.; Manzoli, Jose E.; Geraldo, Aurea B.C.

    2011-01-01

    The polyvinyl chloride (PVC) is a technological and low cost polymer, however it presents high sensitivity to high energy irradiation because of the weakness of carbon-chloride bond face to carbon-carbon and carbon-hydrogen bonds. Grafting is a type of co-polymerization process that can allow it an increase of mechanical characteristics. The aim of this work is to evaluate the mechanical properties of styrene grafted PVC by electron beam irradiation using mutual and pre-irradiation methods to verify the mechanical resistance changes of obtained product whether grafting process is applied from non-irradiated or from pre-irradiated substrates. The irradiation procedures were performed in atmosphere air or inert atmosphere and the irradiation conditions comprised doses from 10 kGy to 100 kGy and dose rates of 2.2 kGy/s and 22.4 kGy/s. The styrene grafted samples were analyzed by gravimetry to determinate the grafting yield; the final values have been averaged from a series of three measurements. The Mid-A TR-FTIR was the spectrophotometer technique used for qualitative/semi-quantitative analysis of grafted samples. The Young's module and tensile strength of pre-irradiated and grafted PVC samples at both methods were measured at a Lloyd LXR tensile tester at a cross-head speed of 10.00 mm/min. We observed the decrease of Young's module and tensile strength with the increase of absorbed dose at pre-irradiated PVC samples. These mechanical parameters results are discussed. (author)

  18. Femtosecond laser-induced ripple patterns for homogenous nanostructuring of pyrolytic carbon heart valve implant

    Science.gov (United States)

    Stępak, Bogusz; Dzienny, Paulina; Franke, Volker; Kunicki, Piotr; Gotszalk, Teodor; Antończak, Arkadiusz

    2018-04-01

    Laser-induced periodic surface structures (LIPSS) are highly periodic wavy surface features which are frequently smaller than incident light wavelength that bring possibility of nanostructuring of many materials. In this paper the possibility of using them to homogeneously structure the surface of artificial heart valve made of PyC was examined. By changing laser irradiation parameters such like energy density and pulse separation the most suitable conditions were established for 1030 nm wavelength. A wide spectrum of periodicities and geometries was obtained. Interesting side effects like creating a thin shell-like layer were observed. Modified surfaces were examined using EDX and Raman spectroscopy to determine change in elemental composition of surface.

  19. Microchemical evolution of irradiated stainless steels

    International Nuclear Information System (INIS)

    Garner, F.A.

    1980-01-01

    The precipitates that develop during irradiation play the dominant role in the response of 300 series alloys, which alters not only the diffusional properties of point defects but also the rate of acceptance of point defects at dislocations and voids. The major elemental participants are carbon, nickel and silicon. Carbon appears to function as a major governing factor of the route and rate by which the radiation-induced evolution proceeds. It is the sensitivity of carbon's response to a wide range of variables that accounts for much of the variability observed in the swelling of 316 stainless steel. Silicon's role is two-fold: while in solution it depresses void nucleation and determines the duration of the void incubation period, and it also coprecipitates with nickel. The eventual level of nickel in the alloy matrix appears to control the steady-state swelling rate and is determined by the silicon and carbon content. The other participating elements appear to affect primarily the distribution and activity of carbon. Dislocations introduced either by irradiation or cold work likewise appear to influence the role of carbon. Several new physical mechanisms appear to be operating: Inverse Kirkendall effect, interstitial-altered phase stability, solute-interstitial binding, infiltration-exchange process, and creation of radiation-stable precipitates. The sensitivity of the latter phenomenon to temperature and flux has been shown to account for much of the unusual behavior of AISI 316 during irradiation

  20. Biofunctionalization of multiwalled carbon nanotubes by irradiation of electropolymerized poly(pyrrole-diazirine) films.

    Science.gov (United States)

    Papper, Vladislav; Gorgy, Karine; Elouarzaki, Kamal; Sukharaharja, Ayrine; Cosnier, Serge; Marks, Robert S

    2013-07-15

    A photoactivatable poly(pyrrole-diazirine) film was synthesized and electropolymerized as a versatile tool for covalent binding of laccase and glucose oxidase on multiwalled carbon nanotube coatings and Pt, respectively. Irradiation of the functionalized nanotubes allowed photochemical grafting of laccase and its subsequent direct electrical wiring, as illustrated by the electrocatalytic reduction of oxygen. Moreover, covalent binding of glucose oxidase as model enzyme, achieved by UV activation of electropolymerized pyrrole-diazirine, allowed a glucose biosensor to be realized. This original method to graft biomolecules combines electrochemical and photochemical techniques. The simplicity of this new method allows it to be extended easily to other biological systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Pyrolytic indices of diagenetic transformation of lignin as biogeochemical proxies for soil organic matter quality and C storage potential

    Science.gov (United States)

    Jiménez-González, Marco A.; Almendros, Gonzalo; Álvarez, Ana M.; Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.

    2017-04-01

    The environmental factors involved in soil organic carbon sequestration remain unclear. The functional relationships between the macromolecular structure of the soil organic matter (SOM) and its resilience has been a constant in classical biogeochemical models. Other more recent hypotheses have postulated that preservation by soil minerals may play a chief role in the accumulation of stable SOM forms. However, additional experimental data are required to demonstrate a cause-to-effect relationship between preservation and stabilization. Some authors might consider that models neglecting the role of macromolecular structure are swapping cause and effect i.e., that SOM structurally flexible, weakly condensed and having 'open' structures is the one with high potential to interact with the soil mineral matrix, leading to stable microaggregates. In this study up to 35 topsoil samples (0-5 cm) were collected from different Spanish soils with contrasted values of organic C (the dependent variable), geological substrate and vegetation type. A wide array of uni- and multivariate chemometric models were applied to independent variables consisting of total abundances of the major aromatic compounds, i.e., alkylbenzenes and methoxyphenols released from whole soil samples using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). These two families of compounds were selected since they are classically considered to inform on the degree of microbial reworking of lignins, which is an important precursor of the aromatic moiety of the SOM. A series of pyrolytic surrogate indices (aiming to express SOM diagenetic transformation in relation to the original biogenic molecular composition) were especially successful in forecasting SOC, viz: a) ratio between alkylbenzenes and methoxyphenols, b) ratio between short-chain (C0-C4) and long-chain (>C4) alkylbenzenes, c) ratio between methoxyphenols and short-chain alkylbenzenes, and d) ratios between methoxyphenols with different side

  2. Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

    Science.gov (United States)

    Huang, Yanqin; Wei, Zhiguo; Yin, Xiuli; Wu, Chuangzhi

    2012-01-01

    Pyrolytic characteristics of acid hydrolysis residue (AHR) of corncob and pinewood (CAHR, WAHR) were investigated using a thermo-gravimetric analyzer (TGA) and a self-designed pyrolysis apparatus. Gasification reactivity of CAHR char was then examined using TGA and X-ray diffractometer. Result of TGA showed that thermal degradation curves of AHR descended smoothly along with temperature increasing from 150 °C to 850 °C, while a "sharp mass loss stage" for original biomass feedstock (OBF) was observed. Char yield from AHR (42.64-30.35 wt.%) was found to be much greater than that from OBF (26.4-19.15 wt.%). In addition, gasification reactivity of CAHR char was lower than that of corncob char, and there was big difference in micro-crystallite structure. It was also found that CAHR char reactivity decreased with pyrolysis temperature, but increased with pyrolysis heating rate and gasification temperature at 850-950 °C. Furthermore, CAHR char reactivity performed better under steam atmosphere than under CO2 atmosphere. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  4. Microscopic and Macroscopic Structures of Carbon Nanotubes Produced by Pyrolysis of Iron Phthalocyanine

    International Nuclear Information System (INIS)

    Huang Shaoming; Dai Liming

    2002-01-01

    By pyrolysis of iron phthalocyanine (FePc), either in a patterned or non-patterned fashion, under an Ar/H 2 atmosphere, we have demonstrated the large-scale production of aligned carbon nanotubes perpendicular to the substrate surface useful for building devices with three-dimensional structures. Depending on the particular pyrolytic conditions used, carbon nanotubes with a wide range of microscopic structures having curved, helical, coiled, branched, and tube-within-tube shapes have also been prepared by the pyrolysis of FePc. This, coupled with several microfabrication methods (photolithography, soft-lithography, self-assembling, micro-contact transfer, etc.), has enabled us to produce carbon nanotube arrays of various macroscopic architectures including polyhedral, flower-like, dendritic, circular, multilayered, and micropatterned geometries. In this article, we summarize our work on the preparation of FePc-generated carbon nanotubes with the large variety of microscopic and macroscopic structures and give a brief overview on the perspectives of making carbon nanotubes with tailor-made microscopic/macroscopic structures, and hence well-defined physicochemical properties, for specific applications

  5. Structural transformations of carbon chains inside nanotubes

    International Nuclear Information System (INIS)

    Warner, Jamie H.; Ruemmeli, Mark H.; Bachmatiuk, Alicja; Buechner, Bernd

    2010-01-01

    In situ aberration-corrected high-resolution transmission electron microscopy is used to examine the structural transformations of carbon chains that occur in the interior region of carbon nanotubes. We find electron-beam irradiation leads to the formation of two-dimensional carbon structures that are freely mobile inside the nanotube. The inner diameter of the nanotube influences the structural transformations of the carbon chains. As the diameter of the nanotube increases, electron-beam irradiation leads to curling of the chains and eventually the formation of closed looped structures. The closed looped structures evolve into spherical fullerenelike structures that exhibit translational motion inside the nanotubes and also coalesce to form larger nanotube structures. These results demonstrate the use of carbon nanotubes as test tubes for growing small carbon nanotubes within the interior by using only electron-beam irradiation at 80 kV.

  6. Mechanical behavior of styrene grafted PVC films by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Jessica R.; Moura, Eduardo; Somessari, Elisabeth S.R.; Silveira, Carlos G.; Paes, Helio A.; Souza, Carlos A.; Manzoli, Jose E.; Geraldo, Aurea B.C., E-mail: ageraldo@ipen.br, E-mail: jmanzoli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The polyvinyl chloride (PVC) is a technological and low cost polymer, however it presents high sensitivity to high energy irradiation because of the weakness of carbon-chloride bond face to carbon-carbon and carbon-hydrogen bonds. Grafting is a type of co-polymerization process that can allow it an increase of mechanical characteristics. The aim of this work is to evaluate the mechanical properties of styrene grafted PVC by electron beam irradiation using mutual and pre-irradiation methods to verify the mechanical resistance changes of obtained product whether grafting process is applied from non-irradiated or from pre-irradiated substrates. The irradiation procedures were performed in atmosphere air or inert atmosphere and the irradiation conditions comprised doses from 10 kGy to 100 kGy and dose rates of 2.2 kGy/s and 22.4 kGy/s. The styrene grafted samples were analyzed by gravimetry to determinate the grafting yield; the final values have been averaged from a series of three measurements. The Mid-A TR-FTIR was the spectrophotometer technique used for qualitative/semi-quantitative analysis of grafted samples. The Young's module and tensile strength of pre-irradiated and grafted PVC samples at both methods were measured at a Lloyd LXR tensile tester at a cross-head speed of 10.00 mm/min. We observed the decrease of Young's module and tensile strength with the increase of absorbed dose at pre-irradiated PVC samples. These mechanical parameters results are discussed. (author)

  7. Dose- and time-dependent gene expression alterations in prostate and colon cancer cells after in vitro exposure to carbon ion and X-irradiation

    Science.gov (United States)

    Suetens, Annelies; Moreels, Marjan; Quintens, Roel; Soors, Els; Buset, Jasmine; Chiriotti, Sabina; Tabury, Kevin; Gregoire, Vincent; Baatout, Sarah

    2015-01-01

    Hadrontherapy is an advanced form of radiotherapy that uses beams of charged particles (such as protons and carbon ions). Compared with conventional radiotherapy, the main advantages of carbon ion therapy are the precise absorbed dose localization, along with an increased relative biological effectiveness (RBE). This high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. Currently, hadrontherapy is being used for the treatment of specific types of cancer. Previous in vitro studies have shown that, under certain circumstances, exposure to charged particles may inhibit cell motility and migration. In the present study, we investigated the expression of four motility-related genes in prostate (PC3) and colon (Caco-2) cancer cell lines after exposure to different radiation types. Cells were irradiated with various absorbed doses (0, 0.5 and 2 Gy) of accelerated 13C-ions at the GANIL facility (Caen, France) or with X-rays. Clonogenic assays were performed to determine the RBE. RT-qPCR analysis showed dose- and time-dependent changes in the expression of CCDC88A, FN1, MYH9 and ROCK1 in both cell lines. However, whereas in PC3 cells the response to carbon ion irradiation was enhanced compared with X-irradiation, the effect was the opposite in Caco-2 cells, indicating cell-type–specific responses to the different radiation types. PMID:25190155

  8. Effects of ion beam irradiation on adventitious shoot regeneration from in vitro leaf explants of Septennial ionahta

    International Nuclear Information System (INIS)

    Zhou, L.B.; Li, W.J.; Ma, S.; Dong, X.C.; Yu, L.X.; Li, Q.; Zhou, G.M.; Gao, Q.X.

    2006-01-01

    The effects of 960 MeV carbon ion beam and 8 MeV X-ray irradiation on adventitious shoots from in vitro leaf explants of two different Saintpaulia ionahta (Mauve and Indikon) cultivars were studied with regard to tissue increase, shoots differentiation and morphology changes in the shoots. The experimental results showed that the survival fraction of shoot formation for the Mauve and Indikon irradiated with the carbon ion beam at 20 Gy were 0.715 and 0.600, respectively, while those for both the cultivars exposed to the X-ray irradiation at the same dose were 1.000. Relative biological effectiveness (RBE) of Mauve with respect to X-ray was about two. Secondly, the percentage of regenerating explants with malformed shoots in all Mauve regenerating explants irradiated with carbon ion beam at 20 Gy accounted for 49.6%, while that irradiated with the same dose of X-ray irradiation was only 4.7%; as for Saintpaulia ionahta Indikon irradiated with 20 Gy carbon ion beam, the percentage was 43.3%, which was higher than that of X-ray irradiation. Last, many chlorophyll deficient and other varieties of mutants were obtained in this study. Based on the results above, it can be concluded that the effect of mutation induction by carbon ion beam irradiation on the leaf explants of Saintpaulia ionahta is better than that by X-ray irradiation; and the optimal mutagenic dose varies from 20 Gy to 25 Gy for carbon ion beam irradiation

  9. The live cell irradiation and observation setup at SNAKE

    Energy Technology Data Exchange (ETDEWEB)

    Hable, V. [Angewandte Physik und Messtechnik LRT2, UniBw-Muenchen, 85577 Neubiberg (Germany)], E-mail: volker.hable@unibw.de; Greubel, C.; Bergmaier, A.; Reichart, P. [Angewandte Physik und Messtechnik LRT2, UniBw-Muenchen, 85577 Neubiberg (Germany); Hauptner, A.; Kruecken, R. [Physik Department E12, TU-Muenchen, 85748 Garching (Germany); Strickfaden, H.; Dietzel, S.; Cremer, T. [Department Biologie II, LMU-Muenchen, 82152 Martinsried (Germany); Drexler, G.A.; Friedl, A.A. [Strahlenbiologisches Institut, LMU-Muenchen, 80336 Muenchen (Germany); Dollinger, G. [Angewandte Physik und Messtechnik LRT2, UniBw-Muenchen, 85577 Neubiberg (Germany)

    2009-06-15

    We describe a new setup at the ion microprobe SNAKE (Superconducting Nanoscope for Applied nuclear (Kern-) physics Experiments) at the Munich 14 MV Tandem accelerator that facilitates both living cell irradiation with sub micrometer resolution and online optical imaging of the cells before and after irradiation by state of the art phase contrast and fluorescence microscopy. The cells are kept at standard cell growth conditions at 37 {sup o}C in cell culture medium. After irradiation it is possible to switch from single ion irradiation conditions to cell observation within 0.5 s. First experiments were performed targeting substructures of a cell nucleus that were tagged by TexasRed labeled nucleotides incorporated in the cellular DNA by 55 MeV single carbon ion irradiation. In addition we show first online sequences of short time kinetics of Mdc1 protein accumulation in the vicinity of double strand breaks after carbon ion irradiation.

  10. Compilation of carbon-14 data

    International Nuclear Information System (INIS)

    Paasch, R.A.

    1985-01-01

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys

  11. Ion irradiation to simulate neutron irradiation in model graphites: Consequences for nuclear graphite

    Science.gov (United States)

    Galy, N.; Toulhoat, N.; Moncoffre, N.; Pipon, Y.; Bérerd, N.; Ammar, M. R.; Simon, P.; Deldicque, D.; Sainsot, P.

    2017-10-01

    Due to its excellent moderator and reflector qualities, graphite was used in CO2-cooled nuclear reactors such as UNGG (Uranium Naturel-Graphite-Gaz). Neutron irradiation of graphite resulted in the production of 14C which is a key issue radionuclide for the management of the irradiated graphite waste. In order to elucidate the impact of neutron irradiation on 14C behavior, we carried out a systematic investigation of irradiation and its synergistic effects with temperature in Highly Oriented Pyrolitic Graphite (HOPG) model graphite used to simulate the coke grains of nuclear graphite. We used 13C implantation in order to simulate 14C displaced from its original structural site through recoil. The collision of the impinging neutrons with the graphite matrix carbon atoms induces mainly ballistic damage. However, a part of the recoil carbon atom energy is also transferred to the graphite lattice through electronic excitation. The effects of the different irradiation regimes in synergy with temperature were simulated using ion irradiation by varying Sn(nuclear)/Se(electronic) stopping power. Thus, the samples were irradiated with different ions of different energies. The structure modifications were followed by High Resolution Transmission Electron Microscopy (HRTEM) and Raman microspectrometry. The results show that temperature generally counteracts the disordering effects of irradiation but the achieved reordering level strongly depends on the initial structural state of the graphite matrix. Thus, extrapolating to reactor conditions, for an initially highly disordered structure, irradiation at reactor temperatures (200 - 500 °C) should induce almost no change of the initial structure. On the contrary, when the structure is initially less disordered, there should be a "zoning" of the reordering: In "cold" high flux irradiated zones where the ballistic damage is important, the structure should be poorly reordered; In "hot" low flux irradiated zones where the ballistic

  12. Synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent and the catalytic oxidation of α-naphthylamine

    Science.gov (United States)

    Song, Y. Z.; Song, Y.; Cheng, Z. P.; Zhou, J. F.; Wei, C.

    2013-01-01

    Electrochemical synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent was proposed. The gold nanoparticles were characterized by scanning electron microscopy, cyclic voltammetry, IR spectra, UV spectra, and powder X-ray diffraction spectra. The electro-chemical catalysis of penicillin for α-naphthylamine was demonstrated.

  13. Study on the development of coating technology for UO{sub 2} nuclear fuel pellet and the microstructural observation of the coated layer

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong; Song, Moon Sup; Cho, In Sik; Kim Yu Sin; Lim Young Kyun [Sunmoon University, Asan (Korea)

    1998-04-01

    In order to enhance inherent safety of UO{sub 2} nuclear fuel pellet and develop future nuclear fuel technology, a coating method for the preparation multi-layers of pyrolytic carbon and silicon carbide on the fuel was developed. Inner pyrolytic carbon layer and outer silicon layer were prepared by thermal decomposition of propane in a fluidized bed type CVD unit and silane in ECR PECVD, respectively. Combustion reaction between two layers resulted in forming silicon carbide layer. The morphology depended on the initial carbon shape. Phase identification and microstructural analysis of the combustion product with XRD, AES, SEM and TEM showed that final products of inner layer and outer layer were pyrolytic carbon with isotropic structure and fine crystalline {beta}-SiC, respectively. This coating process is very useful for the fabrication of coated UO{sub 2} nuclear fuel pellet an future nuclear fuel fabrication technology. (author). 45 refs., 47 figs., 5 tabs.

  14. Catalytic biorefining of plant biomass to non-pyrolytic lignin bio-oil and carbohydrates through hydrogen transfer reactions.

    Science.gov (United States)

    Ferrini, Paola; Rinaldi, Roberto

    2014-08-11

    Through catalytic hydrogen transfer reactions, a new biorefining method results in the isolation of depolymerized lignin--a non-pyrolytic lignin bio-oil--in addition to pulps that are amenable to enzymatic hydrolysis. Compared with organosolv lignin, the lignin bio-oil is highly susceptible to further hydrodeoxygenation under low-severity conditions and therefore establishes a unique platform for lignin valorization by heterogeneous catalysis. Overall, the potential of a catalytic biorefining method designed from the perspective of lignin utilization is reported. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Neutron irradiation effects on plasma facing materials

    Science.gov (United States)

    Barabash, V.; Federici, G.; Rödig, M.; Snead, L. L.; Wu, C. H.

    2000-12-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.

  16. Neutron irradiation effects on plasma facing materials

    International Nuclear Information System (INIS)

    Barabash, V.; Federici, G.; Roedig, M.; Snead, L.L.; Wu, C.H.

    2000-01-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed

  17. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation

    International Nuclear Information System (INIS)

    Secondes, Mona Freda N.; Naddeo, Vincenzo; Belgiorno, Vincenzo; Ballesteros, Florencio

    2014-01-01

    Highlights: • Above 99% of the emerging contaminants were removed in the USAMe process. • Influence of PAC dose and US frequency on removal is studied. • Improved performance is due to PAC adsorption enhancement and sonolytic degradation. • US irradiation improved efficiency and delayed declines in the removal of contaminants. • Performance of the hybrid process is better under lower frequency ultrasound irradiation. -- Abstract: Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs

  18. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Secondes, Mona Freda N. [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines); Naddeo, Vincenzo, E-mail: vnaddeo@unisa.it [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Belgiorno, Vincenzo [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Ballesteros, Florencio [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines)

    2014-01-15

    Highlights: • Above 99% of the emerging contaminants were removed in the USAMe process. • Influence of PAC dose and US frequency on removal is studied. • Improved performance is due to PAC adsorption enhancement and sonolytic degradation. • US irradiation improved efficiency and delayed declines in the removal of contaminants. • Performance of the hybrid process is better under lower frequency ultrasound irradiation. -- Abstract: Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

  19. Thermo-mechanical characterisation of low density carbon foams and composite materials for the ATLAS upgrade

    CERN Document Server

    Isaac, Bonad

    As a result of the need to increase the luminosity of the Large Hadron Collider (LHC) at CERN-Geneva by 2020, the ATLAS detector requires an upgraded inner tracker. Up- grading the ATLAS experiment is essential due to higher radiation levels and high particle occupancies. The design of this improved inner tracker detector involves development of silicon sensors and their support structures. These support structures need to have well un- derstood thermal properties and be dimensionally stable in order to allow efficient cooling of the silicon and accurate track reconstruction. The work presented in this thesis is an in- vestigation which aims to qualitatively characterise the thermal and mechanical properties of the materials involved in the design of the inner tracker of the ATLAS upgrade. These materials are silicon carbide foam (SiC foam), low density carbon foams such as PocoFoam and Allcomp foam, Thermal Pyrolytic Graphite (TPG), carbon/carbon and Carbon Fibre Re- inforced Polymer (CFRP). The work involve...

  20. Resistivity recovery of neutron-irradiated and cold-worked thorium

    International Nuclear Information System (INIS)

    Tang, J.T.

    1976-01-01

    Recovery of neutron-irradiated and cold-worked thorium was studied using electrical resistivity measurements. Thorium wires containing 30 and 300 wt ppM carbon were irradiated to fast neutron fluence of 1.3 x 10 18 n/cm 2 (E greater than 0.1 MeV). Another group of thorium wires containing 45, 300 and 600 wt ppM carbon were laterally compressed 5 to 40 percent. Both irradiation and cold-working were performed at liquid nitrogen temperature. The induced resistivity was found to increase with carbon content for both treatments. Isochronal recovery studies were performed in the 120--420 0 K temperature range. Two recovery stages (II and III) were found for both cold-worked and irradiated samples. In all cases the activation energies were determined by use of the ratio-of-slope method. Consistent results were observed for both irradiated and cold-worked specimens within the experimental error in the two stages. Other methods were also used in determining the activation energy of stage III for irradiated samples. All analysis methods indicated that the activation energies decreased with increasing carbon content for differently treated specimens. Possible reasons for such behavior are discussed. The annealing data obtained do not fit a simple chemical rate equation but follow the empirical exponential equation proposed by Avrami. A model of detrapping of interstitials from impurities is suggested for stage II recovery. On the basis of the observed low activation energy and high retention of defects above stage III, a divacancy migration model is proposed for stage III recovery

  1. Identification and quantitation of anhydrosugars in biomass pyrolytic oils using carbon-13 NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Castola, V.; Bighelli, A. [Universite de Corse, Equipe Chimie et Biomasse, Ajaccio (France); Conti, L.; Scano, G.; Mascia, S. [Universita di Sassari, Dipartimento di Chimica, Sassari (Italy); Casanova, J. [Universite de Corse, Equipe Chimie et Biomasse, Ajaccio (France)

    2000-07-01

    We described a method which allowed identification and quantitation of anhydrosugars in biomass pyrolysis liquids using carbon-13 NMR spectroscopy. The quantitative procedure was checked and validated (accuracy, precision and response linearity) with pure compounds and artificial mixtures. This method was then applied to the analysis of the glucidic fraction obtained after a simple and rapid fractionation of the bio oil. (author)

  2. Effect of pre-stressing on the behaviour of CFRP under gamma irradiation

    International Nuclear Information System (INIS)

    Burnay, S.G.

    1992-01-01

    The effect of pre-stressing on the behaviour of CFRP composites under gamma irradiation has been studied for three materials: 0 deg carbon/epoxy, 0 deg carbon/toughened epoxy and 0 deg/90 deg carbon/PES. Irradiation was carried out at room temperature and at 77 K. Preliminary results illustrate that pre-stressing can significantly affect the degradation of these materials, particularly after irradiation at room temperature. The data indicate that stress cannot be ignored when assessing the durability of structural composites for space applications. This work, which completes the preliminary assessment of low-temperature irradiation effects, has highlighted a number of queries which should be of concern to those using structural composites in space applications. (Author). 15 refs., 17 figs

  3. Change in the structure and properties of carbon fiber-reinforced plastic with a polysulfone matrix under the effect of gamma irradiation

    International Nuclear Information System (INIS)

    Arkhipov, A.A.; Korkhov, V.P.; Pudnik, V.V.; Rodin, Yu.P.

    1993-01-01

    This article presents the results of studying the change in the structure and properties of carbon fiber-reinforced plastic with a thermoplastic matrix -- aromatic polysulfone -- as a function of the absorbed dose of gamma radiation. In view of the presence in the polysulfone macromolecules and in carbon fibers of a large number of aromatic rings and double bonds providing high radiation resistance of the composite, irradiation was carried out up to large values of absorbed doses (10 9 rad). Specimens of orthogonally reinforced composite KTMU-1 with a thickness of 1.3 mm made from aromatic polysulfone PSF-150 and carbon ribbon that absorbed various gamma radiation dosages were used. It was found that structural transformations under the effect of gamma radiation did not have a substantial effect on the mechanical properties of carbon fiber-reinforced plastic. 2 refs., 3 figs., 3 tabs

  4. Neutron transmission measurements of poly and pyrolytic graphite crystals

    Science.gov (United States)

    Adib, M.; Abbas, Y.; Abdel-Kawy, A.; Ashry, A.; Kilany, M.; Kenawy, M. A.

    The total neutron cross-section measurements of polycrystalline graphite have been carried out in a neutron wavelength from 0.04 to 0.78 nm. This work also presents the neutron transmission measurements of pyrolytic graphite (PG) crystal in a neutron wavelength band from 0.03 to 0.50 nm, at different orientations of the PG crystal with regard to the beam direction. The measurements were performed using three time-of-flight (TOF) spectrometers installed in front of three of the ET-RR-1 reactor horizontal channels. The average value of the coherent scattering amplitude for polycrystalline graphite was calculated and found to be bcoh = (6.61 ± 0.07) fm. The behaviour of neutron transmission through the PG crystal, while oriented at different angles with regard to the beam direction, shows dips at neutron wavelengths corresponding to the reflections from (hkl) planes of hexagonal graphite structure. The positions of the observed dips are found to be in good agreement with the calculated ones. It was also found that a 40 mm thick PG crystal is quite enough to reduce the second-order contamination of the neutron beam from 2.81 to 0.04, assuming that the incident neutrons have a Maxwell distribution with neutron gas temperature 330 K.

  5. Neutron transmission measurements of poly and pyrolytic graphite crystals

    International Nuclear Information System (INIS)

    Adib, M.; Abdel-Kawy, A.; Kilany, M.

    1989-01-01

    The total neutron cross-section measurements of polycrystalline graphite have been carried out in a neutron wavelength from 0.04 to 0.78 nm. This work also presents the neutron transmission measurements of pyrolytic graphite (PG) crystal in a neutron wavelength band from 0.03 to 0.50 nm, at different orientations of the PG crystal with regard to the beam direction. The measurements were performed using three time-of-flight (TOF) spectrometers installed in front of three of the ET-RR-1 reactor horizontal channels. The average value of the coherent scattering amplitude for polycrystalline graphite was calculated and found to be b coh = (6.61 ± 0.07) fm. The behaviour of neutron transmission through the PG crystal, while orientated at different angles with regard to the beam direction, shows dips at neutron wavelengths corresponding to the reflections from (hk1) planes of hexagonal graphite structure. The positions of the observed dips are found to be in good agreement with the calculated ones. It was also found that a 40 mm thick PG crystal is quite enough to reduce the second-order contamination of the neutron beam from 2.81 to 0.04, assuming that the incident neutrons have a Maxwell distribution with neutron gas temperature 330 K. (author)

  6. Phase transitions to 120 GPa for shock-compressed pyrolytic and hot-pressed boron nitride

    International Nuclear Information System (INIS)

    Gust, W.H.; Young, D.A.

    1977-01-01

    Shock-compression characteristics of two types of hexagonal graphitelike boron nitride have been investigated. Highly oriented very pure pyrolytic boron nitride exhibits shock-velocity versus particle-velocity discontinuities that appear to be manifestations of the initiation of a sluggish phase transition. This transition begins at 20 GPa and is driven to completion (melting) at 75 GPa. Discontinuities in the plot for impure hot-pressed boron nitride indicate initiation at 10 GPa and completion at 20 GPa. The (U/sub s/, U/sub p/) plots follow essentially the same paths for 4.0 < U/sub p/ < 5.2 km/sec. No evidence for a transition to a metalliclike state was seen. Temperature calculations indicate that the material is liquid above approx.80 GPa

  7. In vivo studies on the efficiency of irradiation with carbon ions at the syngeneic prostate carcinoma model R3327; In vivo Untersuchungen zur Wirksamkeit von Bestrahlungen mit Kohlenstoffionen am syngenen Prostatakarzinom Modell R3327

    Energy Technology Data Exchange (ETDEWEB)

    Glowa, Christin

    2013-07-01

    The aim of this study is to characterize differential effects after carbon ion ({sup 12}C) relative to photon irradiations in vivo in three different sublines of the syngeneic rat prostate adenocarcinoma (PCa) R3327 (AT1, HI, and H) as well as to identify tumor specific influence factors of the radiation response. Subcutaneous PCa tumor fragments in rats were irradiated with single (1 Fx) or split (2 Fx) doses of photons or carbon ions (75 keV/μ), respectively. Primary endpoint was local tumor control after 300 days. Based on dose-response curves, the TCD{sub 50{sup -}} values (dose at 50% tumor control probability) were used to calculate the relative biological effectiveness (RBE) of carbon ions. Additionally, potential carbon ion specific irradiation effects were studied. For this, in vivo tumor-physiological changes, structural and functional radiation- induced effects of gene expression as well as tumor subpopulations with tumor-inducing properties were investigated. For {sup 12}C- irradiations with 1 Fx or 2 Fx, the RBEs were 1.62 (H), 2.08 (HI) and 2.3 (AT1) and 1.9 (H), 2.1 (HI) and 2.67 (AT1), respectively. Isoeffective irradiation with photons and {sup 12}C- ions showed different kinetics of the radiation response. Magnetic resonance imaging (MRI) and histology showed a faster and stronger increase of tumor vessel permeability after {sup 12}C- irradiation compared to photons. After irradiation, DNA-repair mechanisms, immune system components and migration were induced, in contrast cell cycle progression, adhesion, angiogenesis, and the aerobic metabolism were downregulated. Especially, the kinetics of signaling cascades, apoptosis and stress-response were dependent on irradiation modality. In HI- and H-tumors CD24{sup +}/CD45{sup -} cells were identified as tumor inducing cells (TICs) in vivo. All three sublines were established under cell culture conditions to enable further molecular biological analyses. In conclusion, {sup 12}C- irradiation is

  8. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D. [Laboratoire PROMES-CNRS, Laboratoire Procedes, Materiaux et Energie Solaire, 7 rue du Four Solaire, 66120 Font-Romeu Odeillo (France)

    2007-07-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H{sup +} ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  9. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    International Nuclear Information System (INIS)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D.

    2007-01-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H + ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  10. Effect of Anorganic Substance on Physical Properties of Poly (Butylene Succinate -co- Adipate) Irradiated by Electron Beam

    International Nuclear Information System (INIS)

    Meri Suhartini

    2004-01-01

    Poly(butylene succinate-co-adipate), PBSA were electron beam irradiated in the presence of inorganic materials. The samples gave high gel fraction by irradiation in the presence of 2% silicon dioxide and 2% carbon black. It was found that addition of carbon black (CB) was effective for improving the heat stability of the sample. This is because of three-dimensional carbon black- polymer networks. Irradiated PBSA sheets broke immediately at 110 o C with load 6.67 kgf/cm 2 , while irradiated the same sample mixed with 2% carbon black did not break at the same condition. Biodegradability of crosslinked PBSA by soil burial tests was accelerated by addition of carbon black. (author)

  11. Fully portable blood irradiator

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1980-01-01

    A fully portable blood irradiator was developed using the beta emitter thulium-170 as the radiation source and vitreous carbon as the body of the irradiator, matrix for isotope encapsulation, and blood interface material. These units were placed in exteriorized arteriovenous shunts in goats, sheep, and dogs and the effects on circulating lymphocytes and on skin allograft retention times measured. The present work extends these studies by establishing baseline data for skin graft rejection times in untreated animals

  12. Chronic blood irradiation: a new approach

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.; Gillis, M.F.

    1976-01-01

    Extracorporeal irradiation of blood is beneficial in suppressing early rejection of renal allografts and in treating chronic lymphocytic leukemia. Previously, nearly all blood irradiation has involved brief intermittent exposures with high dose rates. The small amount of data available involving chronic irradiation suggests that doses given chronically at lower rates are more effective in suppressing graft rejection. However, no suitably portable device has been available to permit chronic irradiation. This work has been directed toward developing a fully portable irradiator. After preliminary testing of a variety of source materials, 170 Tm was selected for its favorable beta energy, low cost, and compatibility with the fabrication requirements. The body of the irradiator is cast from polyfurfuryl alcohol with subsequent high-temperature conversion to vitreous carbon. By sequential layering of the alcohol and suspending of 169 Tm 2 O 3 in the midlayer, a unit is produced without any radiation exposure and with the source material contained on both a macro and a micro scale. Exposure of the unit to reactor neutrons produces 170 Tm without activation of the vitreous carbon. A 170 Tm irradiator giving a transit dose of 16 rads (100 ml/min flow) was connected in a carotid--jugular shunt on a 20-kg goat. Lymphocyte levels decreased to about 15 percent of the preexposure level during the first week and thereafter slowly rose to about 50 percent of preexposure levels 2 months after exposure. Reciprocal skin grafts made at the end of irradiation (12 days) were rejected at 12 days on the nonirradiated control and at 24 days on the irradiated goat. These results are consistent with data reported on chronically irradiated baboons even though the dose rate for the present test was only about one-fourth that for the baboons

  13. Apparatus for measuring the release of fission gases and other fission products by degassing

    Energy Technology Data Exchange (ETDEWEB)

    Stradal, Karl Alfred

    1970-10-15

    In gas-cooled high-temperature reactors, the fuel is, in general, inserted in the fuel elements in the form of small particles, which are, for example, coated with pyrolytic carbon. The purpose of this coating is to keep the fission products separate from the coolant gas. The further development of these coated particles makes it necessary to check the retention capacity. One possible method of doing this is the degassing test after irradiation in the reactor. An apparatus is described below, which was developed and installed in order to measure to a higher degree of sensitivity and in serial measurements the release of fission gases and sparingly volatile fission products.

  14. Ion irradiation used as surrogate of neutron irradiation in graphite: Consequences on 14C and 36Cl behavior and structural evolution

    Science.gov (United States)

    Galy, N.; Toulhoat, N.; Moncoffre, N.; Pipon, Y.; Bérerd, N.; Ammar, M. R.; Simon, P.; Deldicque, D.; Sainsot, P.

    2018-04-01

    isotopes were implanted into Highly Oriented Pyrolytic Graphite (HOPG) samples used as a model material system representative of the nuclear graphite coke grains which form around 80% of nuclear graphite. Nuclear graphite is manufactured from petroleum coke grains (filler) blended with coal tar pitch acting as a binder. Shaped blocks are formed by extrusion of the blend. They are heat-treated up to about 2800 °C (graphitisation treatment) and polycrystalline graphite is obtained. Blocks, intended for the moderator or reflector, may be further impregnated with pitch, re-baked and regraphitised in order to increase the density. Virgin nuclear graphites have initial densities in the range 1.6-1.8 g cm-3. The difference with graphite crystal (density = 2.265 g cm-3) is due to internal porosity. As a result of mixing of several carbon compounds, this material is structurally heterogeneous at a local scale. Nuclear graphite presents a complex multiscale organisation. It can be locally more or less anisotropic and not completely graphitised. Nuclear graphite has a polycrystalline structure and contains micrometer sized grains. The grains are formed by several more or less oriented crystallites with a size of a few hundreds nanometers. Each crystallite is formed by a triperiodical stacking of graphene planes. Nuclear graphite contains also small amounts of impurities like oxygen, hydrogen, metals and halogens, among them chlorine [4]. Ion beam irradiation was used as a surrogate for neutrons because it may produce cascades (due to ballistic interactions) that could be similar to those created by neutrons in the nuclear reactor. Ion beam (or electron beam) irradiation has been used for many years to simulate neutron irradiation. It has advantages such as for example the possibility to vary the irradiation conditions and sometimes to carry out in situ observations. Moreover, depending on the ion nature and energy, it allows covering a broad range of the neutron recoil spectrum and

  15. Influence of Cu(NO32 initiation additive in two-stage mode conditions of coal pyrolytic decomposition

    Directory of Open Access Journals (Sweden)

    Larionov Kirill

    2017-01-01

    Full Text Available Two-stage process (pyrolysis and oxidation of brown coal sample with Cu(NO32 additive pyrolytic decomposition was studied. Additive was introduced by using capillary wetness impregnation method with 5% mass concentration. Sample reactivity was studied by thermogravimetric analysis with staged gaseous medium supply (argon and air at heating rate 10 °C/min and intermediate isothermal soaking. The initiative additive introduction was found to significantly reduce volatile release temperature and accelerate thermal decomposition of sample. Mass-spectral analysis results reveal that significant difference in process characteristics is connected to volatile matter release stage which is initiated by nitrous oxide produced during copper nitrate decomposition.

  16. Irradiation of zinc single crystal with 500 keV singly-charged carbon ions: surface morphology, structure, hardness, and chemical modifications

    Science.gov (United States)

    Waqas Khaliq, M.; Butt, M. Z.; Saleem, Murtaza

    2017-07-01

    Cylindrical specimens of (1 0 4) oriented zinc single crystal (diameter  =  6 mm and length  =  5 mm) were irradiated with 500 keV C+1 ions with the help of a Pelletron accelerator. Six specimens were irradiated in an ultra-high vacuum (~10‒8 Torr) with different ion doses, namely 3.94  ×  1014, 3.24  ×  1015, 5.33  ×  1015, 7.52  ×  1015, 1.06  ×  1016, and 1.30  ×  1016 ions cm-2. A field emission scanning electron microscope (FESEM) was utilized for the morphological study of the irradiated specimens. Formation of nano- and sub-micron size rods, clusters, flower- and fork-like structures, etc, was observed. Surface roughness of the irradiated specimens showed an increasing trend with the ions dose. Energy dispersive x-ray spectroscopy (EDX) helped to determine chemical modifications in the specimens. It was found that carbon content varied in the range 22.86-31.20 wt.% and that oxygen content was almost constant, with an average value of 10.16 wt.%. The balance content was zinc. Structural parameters, i.e. crystallite size and lattice strain, were determined by Williamson-Hall analysis using x-ray diffraction (XRD) patterns of the irradiated specimens. Both crystallite size and lattice strain showed a decreasing trend with the increasing ions dose. A good linear relationship between crystallite size and lattice strain was observed. Surface hardness depicted a decreasing trend with the ions dose and followed an inverse Hall-Petch relation. FTIR spectra of the specimens revealed that absorption bands gradually diminish as the dose of singly-charged carbon ions is increased from 3.94  ×  1014 ions cm-1 to 1.30  ×  1016 ions cm-1. This indicates progressive deterioration of chemical bonds with the increase in ion dose.

  17. A carbon-carbon composite materials development program for fusion energy applications

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eatherly, W.P.; Engle, G.B.; Hollenberg, G.W.

    1992-10-01

    Carbon-carbon composites increasingly are being used for plasma-facing component (PFC) applications in magnetic-confinement plasma-fusion devices. They offer substantial advantages such as enhanced physical and mechanical properties and superior thermal shock resistance compared to the previously favored bulk graphite. Next-generation plasma-fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER) and the Burning Plasma Experiment (BPX), will require advanced carbon-carbon composites possessing extremely high thermal conductivity to manage the anticipated extreme thermal heat loads. This report outlines a program that will facilitate the development of advanced carbon-carbon composites specifically tailored to meet the requirements of ITER and BPX. A strategy for developing the necessary associated design data base is described. Materials property needs, i.e., high thermal conductivity, radiation stability, tritium retention, etc., are assessed and prioritized through a systems analysis of the functional, operational, and component requirements for plasma-facing applications. The current Department of Energy (DOE) Office of Fusion Energy Program on carbon-carbon composites is summarized. Realistic property goals are set based upon our current understanding. The architectures of candidate PFC carbon-carbon composite materials are outlined, and architectural features considered desirable for maximum irradiation stability are described. The European and Japanese carbon-carbon composite development and irradiation programs are described. The Working Group conclusions and recommendations are listed. It is recommended that developmental carbon-carbon composite materials from the commercial sector be procured via request for proposal/request for quotation (RFP/RFQ) as soon as possible

  18. Pyrolytic and kinetic characteristics of the thermal decomposition of Perilla frutescens polysaccharide.

    Directory of Open Access Journals (Sweden)

    Quancheng Zhou

    Full Text Available The thermal decomposition of Perilla frutescens polysaccharide was examined by thermogravimetry, differential thermogravimetry, and differential thermal analysis. The results showed that the mass loss of the substance proceeded in three steps. The first stage can be attributed to the expulsion of the water from ambient temperature to 182°C. The second stage corresponded to devolatilization from 182°C to 439°C. The residue slowly degraded in the third stage. The weight loss in air is faster than that in nitrogen, because the oxygen in air accelerated the pyrolytic reaction speed reaction. The heating rate significantly affected the pyrolysis of the sample. Similar activation energies of the degradation process (210-211 kJ mol⁻¹ were obtained by the FWO, KAS, and Popescu techniques. According to Popescu mechanism functions, the possible kinetic model was estimated to be Avrami-Erofeev 20 g(α = [-ln(1-α]⁴.

  19. Gadolinium oxide decorated multiwalled carbon nanotube/tridoped titania nanocomposites for improved dye degradation under simulated solar light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mamba, Gcina [Department of Applied Chemistry, University of Johannesburg, Faculty of Science, P.O. Box 17011, Doornfontein 2028 (South Africa); Nanotechnology and Water Sustainability Research Unit, College of Engineering, Science and Technology, University of South Africa Florida Science Campus, 1709 Florida (South Africa); Mbianda, Xavier Yangkou [Department of Applied Chemistry, University of Johannesburg, Faculty of Science, P.O. Box 17011, Doornfontein 2028 (South Africa); Mishra, Ajay Kumar, E-mail: mishrak@unisa.ac.za [Nanotechnology and Water Sustainability Research Unit, College of Engineering, Science and Technology, University of South Africa Florida Science Campus, 1709 Florida (South Africa)

    2016-03-15

    Graphical abstract: Illustration of the collaborative effect between MWCNT-Gd and Gd,N,S-TiO{sub 2} towards degradation of AB 74. - Highlights: • MWCNT-Gd/tridoped titania was successfully prepared via a sol-gel method. • XPS revealed the presence of Ti, C, O, S, N and Gd in MWCNT-Gd/Gd,N,S-TiO{sub 2}. • MWCNT-Gd/Gd,N,S-TiO{sub 2} displayed 100% degradation of acid blue 74 in 150 min. • Over 60% TOC removal by MWCNT-Gd/Gd,N,S-TiO{sub 2}. - Abstract: Neodymium/gadolinium/europium, nitrogen and sulphur tridoped titania (Nd/Gd/Eu, N,S-TiO{sub 2}) was hybridised with pre-synthesised gadolinium oxide decorated multiwalled carbon nanotubes (MWCNT-Gd) using a sol–gel method. Subsequent to drying and calcination, composite photocatalysts: MWCNT-Gd/Nd,N,S-TiO{sub 2}, MWCNT-Gd/Gd,N,S-TiO{sub 2} and MWCNT-Gd/Eu,N,S-TiO{sub 2}, were obtained and characterised using TEM, SEM-EDX, UV–vis, XPS, XRD and FT-IR. Acid blue 74 (AB74) was used as a model dye to investigate the photocatalytic degradation properties of the prepared materials under simulated solar light irradiation. Coupling the different tridoped titania with MWCNT-Gd enhanced their activity compared to MWCNT/TiO{sub 2}, MWCNT-Gd/TiO{sub 2} and MWCNT/Gd,N,S-TiO{sub 2}. MWCNT-Gd/Gd,N,S-TiO{sub 2} showed the highest activity towards AB74 degradation reaching 100% decolourisation after 150 min of irradiation. Total organic carbon analysis revealed that over 50% of the AB74 molecules were completely mineralised after 180 min of irradiation in the presence of MWCNT-Gd/Gd,N,S-TiO{sub 2}.

  20. Quantitative analysis of complexes in electron irradiated CZ silicon

    International Nuclear Information System (INIS)

    Inoue, N.; Ohyama, H.; Goto, Y.; Sugiyama, T.

    2007-01-01

    Complexes in helium or electron irradiated silicon are quantitatively analyzed by highly sensitive and accurate infrared (IR) absorption spectroscopy. Carbon concentration (1x10 15 -1x10 17 cm -3 ) and helium dose (5x10 12 -5x10 13 cm -2 ) or electron dose (1x10 15 -1x10 17 cm -2 ) are changed by two orders of magnitude in relatively low regime compared to the previous works. It is demonstrated that the carbon-related complex in low carbon concentration silicon of commercial grade with low electron dose can be detected clearly. Concentration of these complexes is estimated. It is clarified that the complex configuration and thermal behavior in low carbon and low dose samples is simple and almost confined within the individual complex family compared to those in high concentration and high dose samples. Well-established complex behavior in electron-irradiated sample is compared to that in He-irradiated samples, obtained by deep level transient spectroscopy (DLTS) or cathodoluminescence (CL), which had close relation to the Si power device performance

  1. Sustainable Steel Carburization by Using Snack Packaging Plastic Waste as Carbon Resources

    Directory of Open Access Journals (Sweden)

    Songyan Yin

    2018-01-01

    Full Text Available In recent years, the research regarding waste conversion to resources technology has attracted growing attention with the continued increase of waste accumulation issues and rapid depletion of natural resources. However, the study, with respect to utilizing plastics waste as carbon resources in the metals industry, is still limited. In this work, an environmentally friendly approach to utilize snack packaging plastic waste as a valuable carbon resources for steel carburization is investigated. At high temperature, plastic waste could be subject to pyrolytic gasification and decompose into small molecular hydrocarbon gaseous products which have the potential to be used as carburization agents for steel. When heating some snack packaging plastic waste and a steel sample together at the carburization temperature, a considerable amount of carbon-rich reducing gases, like methane, could be liberated from the plastic waste and absorbed by the steel sample as a carbon precursor for carburization. The resulting carburization effect on steel was investigated by optical microscopy, scanning electron microscopy, electron probe microanalyzer, and X-ray photoelectron spectrometer techniques. These investigation results all showed that snack packaging plastic waste could work effectively as a valuable carbon resource for steel carburization leading to a significant increase of surface carbon content and the corresponding microstructure evolution in steel.

  2. Evaporative behavior of carbon with MPD Arc Jet

    Energy Technology Data Exchange (ETDEWEB)

    Sukegawa, Toshio; Madarame, Haruki; Okamoto, Koji [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Using the Magneto-Plasma-Dynamic Arc Jet (MPD Arc Jet) device, the plasma-material interaction during simulated plasma disruption was experimentally investigated. To clarify the effects of the evaporation, the isotropic graphite was used as a target. The thermal conductivity of the isotropic graphite was much higher than that of the pyrolytic graphite, resulting in smaller evaporation. The light intensity distribution during the simulated disruption for the isotropic graphite was quite different from that for the pyrolytic graphite. (author)

  3. Angle-dependent light emission from aligned multiwalled carbon nanotubes under CO2 laser irradiation

    International Nuclear Information System (INIS)

    Zhang, Y; Gong, T; Liu, W J; Wei, J Q; Zhang, X F; Wang, K L; Zhong, M L; Wu, D H

    2007-01-01

    This paper reports the light emission from aligned multiwalled carbon nanotubes (MWNTs) under continuous wave CO 2 laser (λ = 10.6 μm) irradiation. Results indicate that the light emission is dependent on the angle θ between the laser incident direction and the nanotube axis. The relative intensity of the light emission at certain wavelengths shows a Lorentzian feature when θ varies from 0 0 to 90 0 . The Lorentzian fitting curve displays a distinct tendency between shorter (λ 700 nm). A minimum intensity was observed at θ m close to 67 0 under shorter wavelength, whereas a maximum intensity was shown at θ m of about 60 0 at longer wavelength. These results show the anisotropic property of aligned MWNTs

  4. SU-E-J-37: Feasibility of Utilizing Carbon Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation

    International Nuclear Information System (INIS)

    Zhang, Y; Hieken, T; Mutter, R; Park, S; Yan, E; Brinkmann, D; Pafundi, D

    2015-01-01

    Purpose To investigate the feasibility of utilizing carbon fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). Methods Carbon fiducials were placed intraoperatively in the lumpectomy cavity following resection of breast cancer in 11 patients. The patients were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI patients were initially setup to skin tattoos using lasers, followed by orthogonal kV on-board-imaging (OBI) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, patients were setup with lasers, followed by OBI matching to fiducials, with final alignment by CBCT matching to fiducials. Using carbon fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, OBI bone, OBI fiducials, and CBCT breast were compared. Results Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on OBI for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm ± 5.3 mm (n=84), 7.3mm ± 3.7mm (n=87), 2.2mm ± 1.6mm (n=40) and 4.8mm ± 2.6mm (n=87), for lasers, OBI bone, OBI fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a patient with a large postoperative seroma. Conclusion OBI carbon fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using OBI bone matching to 3mm using OBI fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing carbon fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios

  5. SU-E-J-37: Feasibility of Utilizing Carbon Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Hieken, T; Mutter, R; Park, S; Yan, E; Brinkmann, D; Pafundi, D [Mayo Clinic, Rochester, MN (United States)

    2015-06-15

    Purpose To investigate the feasibility of utilizing carbon fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). Methods Carbon fiducials were placed intraoperatively in the lumpectomy cavity following resection of breast cancer in 11 patients. The patients were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI patients were initially setup to skin tattoos using lasers, followed by orthogonal kV on-board-imaging (OBI) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, patients were setup with lasers, followed by OBI matching to fiducials, with final alignment by CBCT matching to fiducials. Using carbon fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, OBI bone, OBI fiducials, and CBCT breast were compared. Results Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on OBI for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm ± 5.3 mm (n=84), 7.3mm ± 3.7mm (n=87), 2.2mm ± 1.6mm (n=40) and 4.8mm ± 2.6mm (n=87), for lasers, OBI bone, OBI fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a patient with a large postoperative seroma. Conclusion OBI carbon fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using OBI bone matching to 3mm using OBI fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing carbon fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios

  6. Carbon coating of simulated nuclear-waste material

    International Nuclear Information System (INIS)

    Blocher, J.M. Jr.; Browning, M.F.; Kidd, R.W.

    1982-03-01

    The development of low-temperature pyrolytic carbon (LT-PyC) coatings as described in this report was initiated to reduce the release of volatile waste form components and to permit the coating of larger glass marbles that have low temperature softening points (550 to 600 0 C). Fluidized bed coaters for smaller particles ( 2mm) were used. Coating temperatures were reduced from >1000 0 C for conventional CVD high temperature PyC to approx. 500 0 C by using a catalyst. The coating gas combination that produced the highest quality coatings was found to be Ni(CO) 4 as the catalyst, C 2 H 2 as the carbon source gas, and H 2 as a diluent. Carbon deposition was found to be temperature dependent with a maximum rate observed at 530 0 C. Coating rates were typically 6 to 7 μm/hour. The screw-agitated coater approach to coating large-diameter particles was demonstrated to be feasible. Clearances are important between the auger walls and coater to eliminate binding and attrition. Coatings prepared in fluidized bed coaters using similar parameters are better in quality and are deposited at two to three times the rate as in screw-agitated coaters

  7. Chemical and Pyrolytic Thermogravimetric Characterization of Nigerian Bituminous Coals

    Directory of Open Access Journals (Sweden)

    Nyakuma Bemgba Bevan

    2016-12-01

    Full Text Available The discovery of new coal deposits in Nigeria presents solutions for nation’s energy crises and prospects for socioeconomic growth and sustainable development. Furthermore, the quest for sustainable energy to limit global warming, climate change, and environmental degradation has necessitated the exploration of alternatives using cleaner technologies such as coal pyrolysis. However, a lack of comprehensive data on physico-chemical and thermal properties of Nigerian coals has greatly limited their utilization. Therefore, the physico-chemical properties, rank (classification, and thermal decomposition profiles of two Nigerian bituminous coals – Afuze (AFZ and Shankodi-Jangwa (SKJ – were examined in this study. The results indicate that the coals contain high proportions of C, H, N, S, O and a sufficiently high heating value (HHV for energy conversion. The coal classification revealed that the Afuze (AFZ coal possesses a higher rank, maturity, and coal properties compared to the Shankodi-Jangwa (SKJ coal. A thermal analysis demonstrated that coal pyrolysis in both cases occurred in three stages; drying (30-200 °C, devolatilization (200-600 °C, and char decomposition (600-1000 °C. The results also indicated that pyrolysis at 1000 °C is not sufficient for complete pyrolysis. In general, the thermochemical and pyrolytic fuel properties indicate that the coal from both places can potentially be utilized for future clean energy applications.

  8. Synthesis of carbon-13 labelled carbonaceous deposits and their evaluation for potential use as surrogates to better understand the behaviour of the carbon-14-containing deposit present in irradiated PGA graphite

    Energy Technology Data Exchange (ETDEWEB)

    Payne, L., E-mail: liam.payne@bristol.ac.uk [Interface Analysis Centre, HH Wills Physics Laboratory, University of Bristol, BS8 1TL (United Kingdom); Walker, S.; Bond, G. [Centre for Materials Science, University of Central Lancashire, PR1 2HE (United Kingdom); Eccles, H. [John Tyndall Institute for Nuclear Research, School of Computing, Engineering and Physical Sciences, University of Central Lancashire, PR1 2HE (United Kingdom); Heard, P.J.; Scott, T.B. [Interface Analysis Centre, HH Wills Physics Laboratory, University of Bristol, BS8 1TL (United Kingdom); Williams, S.J. [Radioactive Waste Management, B587, Curie Avenue, Harwell Oxford, Didcot, OX11 0RH (United Kingdom)

    2016-03-15

    The present work has used microwave plasma chemical vapour deposition to generate suitable isotopically labelled carbonaceous deposits on the surface of Pile Grade A graphite for use as surrogates for studying the behaviour of the deposits observed on irradiated graphite extracted from UK Magnox reactors. These deposits have been shown elsewhere to contain an enhanced concentration of {sup 14}C compared to the bulk graphite. A combination of Raman spectroscopy, ion beam milling with scanning electron microscopy and secondary ion mass spectrometry were used to determine topography and internal morphology in the formed deposits. Direct comparison was made against deposits found on irradiated graphite samples trepanned from a Magnox reactor core and showed a good similarity in appearance. This work suggests that the microwave plasma chemical vapour deposition technique is of value in producing simulant carbon deposits, being of sufficiently representative morphology for use in non-radioactive surrogate studies of post-disposal behaviour of {sup 14}C-containing deposits on some irradiated Magnox reactor graphite.

  9. Hydrothermal carbonization. Investigation of process parameters

    Energy Technology Data Exchange (ETDEWEB)

    Steinbrueck, J.; Rossbach, M.; Reichert, D.; Bockhorn, H. [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. of Technical Chemistry and Polymerchemistry; Walz, L. [Energie Baden-Wuerttemberg AG, Karlsruhe (Germany); Eyler, D. [European Institute for Energy Research, Karlsruhe (Germany)

    2010-07-01

    For energetic use and as a raw material lignocellulosic biomass becomes more and more important. Among pyrolytic refining, the hydrothermal treatment can be an alternative way to deoxygenerate biomass. The objective of this study is to gain deeper insights into the Hydrothermal Carbonization (HTC) process and also to define basic parameters for the construction of a small pilot plant. The biomass is converted in an autoclave at temperatures between 180 C and 240 C establishing the respective vapour pressure. Reaction times between 1 and 12 hours are applied and various catalysts in different concentrations are tested. Elemental analysis of the product, a brown coal-like solid, shows a composition of ca. C{sub 4}H{sub 3}O{sub 1}, corresponding to a carbon recovery of 60% of initial carbon mass. The elemental composition of the product is independent of the process temperature and the applied biomass, if a minimal reaction time is adhered, which however heavily depends on the reaction temperature. The remaining carbon species in intermediate reaction products in the liquid and gas phase are characterised by use of GC/MS, HPLC and FTIR. From the experimental data a two-way mechanism is deduced that includes a rapid formation of an initial solid and dehydration and decomposition reactions which lead to smaller organic molecules, e.g. furfural and aromatic species, and can be promoted by acid catalysis, e.g. H{sub 2}SO{sub 4}. (orig.)

  10. Efficiency of radical yield in alkylthymine and alkyluracil by high-LET irradiation

    International Nuclear Information System (INIS)

    Nakagawa, Seiko; Ohta, Nobuaki; Murakami, Takeshi

    2010-01-01

    Penthylthymines and hexyl-, nonyl-, and decyl- uracils were irradiated by C-ion (3.5 GeV) and γ-ray at 77 K. ESR spectra were measured to study radiation induced radicals in the temperature range from 108 to 273 K. A dihydro-5-yl (5-yl) radical formed by H addition to C6 carbon and a secondary alkyl radical by C-H bond fission at the second carbon from the end of the alkyl group were produced at 108 K. A dihydrouracil-6-yl (6-yl) radical formed by H addition to C5 carbon increased with increasing temperature for alkyluracils. The spectral feature obtained by C-ion irradiation was coincident with that by γ-irradiation. Total radical yields increased by alkylation and with increasing the length of alkyl chain. Yields of both 5-yl and secondary alkyl radicals irradiated by C-ion were less than those by γ-ray for penthylthymines and hexyluracil. On the contrary, radical yields were almost the same between ion and γ-ray irradiation for nonyl- and decyl-uracil. Mechanism of radical formation and effect of high-LET irradiation were discussed.

  11. Changes in optical properties of polystyrene thin films by proton beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sung Hyun; Jung, Jin Mook; Choi, Jae Hak [Dept. of of Polymer Science and Engineering, Chungnam National University, Daejeon (Korea, Republic of); Jung, Chan Hee; Hwang, In Tae; Shin, Jun Hwa [Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup(Korea, Republic of)

    2017-06-15

    In this study, changes in optical properties of polystyrene (PS) thin films by proton irradiation were investigated. PS thin films were irradiated with 150 keV proton ions at fluences ranging from 1 × 10{sup 15} to 1 × 10{sup 16} ions cm{sup -2}. The chemical structures and optical properties of proton beam-irradiated PS thin films were investigated by using a FT-IR spectrometer, an UVvis spectrophotometer, a photoluminescence (PL) and a fluorescence microscope. The results of the chemical structure analysis revealed that chemical functional groups, such as OH, C=O, and C=C, were formed in the PS films due to the oxidation and formation of carbon clusters by proton beam irradiation. The PL emission was generated and gradually red-shifted with an increasing fluence due to the higher formation of sp2 carbon clusters by proton beam irradiation. The highest PL intensity was obtained at a fluence of 5×10{sup 15} ions cm{sup -2}. The optical band gap of PS calculated by using a Tauc’s plot decreased with increasing the fluence due to the formation of sp2 carbon clusters by proton beam irradiation.

  12. Cadmium sulphide thin film for application in gamma radiation ...

    African Journals Online (AJOL)

    Cadmium Sulphide (CdS) thin film was prepared using pyrolytic spraying technique and then irradiated at varied gamma dosage. The CdS thin film absorption before gamma irradiation was 0.6497. Absorbed doses were computed using standard equation established for an integrating dosimeter. The plot of absorbed dose ...

  13. Electronic structure of multi-walled carbon fullerenes

    International Nuclear Information System (INIS)

    Doore, Keith; Cook, Matthew; Clausen, Eric; Lukashev, Pavel V; Kidd, Tim E; Stollenwerk, Andrew J

    2017-01-01

    Despite an enormous amount of research on carbon based nanostructures, relatively little is known about the electronic structure of multi-walled carbon fullerenes, also known as carbon onions. In part, this is due to the very high computational expense involved in estimating electronic structure of large molecules. At the same time, experimentally, the exact crystal structure of the carbon onion is usually unknown, and therefore one relies on qualitative arguments only. In this work we present the results of a computational study on a series of multi-walled fullerenes and compare their electronic structures to experimental data. Experimentally, the carbon onions were fabricated using ultrasonic agitation of isopropanol alcohol and deposited onto the surface of highly ordered pyrolytic graphite using a drop cast method. Scanning tunneling microscopy images indicate that the carbon onions produced using this technique are ellipsoidal with dimensions on the order of 10 nm. The majority of differential tunneling spectra acquired on individual carbon onions are similar to that of graphite with the addition of molecular-like peaks, indicating that these particles span the transition between molecules and bulk crystals. A smaller, yet sizable number exhibited a semiconducting gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels. These results are compared with the electronic structure of different carbon onion configurations calculated using first-principles. Similar to the experimental results, the majority of these configurations are metallic with a minority behaving as semiconductors. Analysis of the configurations investigated here reveals that each carbon onion exhibiting an energy band gap consisted only of non-metallic fullerene layers, indicating that the interlayer interaction is not significant enough to affect the total density of states in these structures. (paper)

  14. Thermal desorption spectroscopy of boron/carbon films after keV deuterium irradiation

    International Nuclear Information System (INIS)

    Yamaki, T.; Gotoh, Y.; Ando, T.; Jimbou, R.; Ogiwara, N.; Saidoh, M.

    1994-01-01

    Thermal desorption spectroscopy (TDS) of D 2 and CD 4 was done on boron/carbon films (B/(B+C)=0-74%), after 3 keV D 3 + irradiation to 4.5x10 17 D/cm 2 at 473 K. The D 2 desorption peaks were observed at 1050, 850 and 650 K. For a sputter B/C film (0%), only the 1050 K peak was observed. With increasing boron concentration to 3%, a sharp peak appeared at 850 K, the intensity of which was found to increase with increasing boron concentration to 23%, and then to decrease at 74%. The 650 K shoulder, which was observed for high boron concentration specimens, was speculated to be deuterium trapped by boron atoms in the boron clusters. The relative amount of CD 4 desorption was found to decrease with increasing boron concentration, which was attributed to the decrease in the trapped deuterium concentration in the implantation layer at temperatures at which CD 4 desorption proceeds. ((orig.))

  15. The analysis of irradiated nuclear fuel and cladding materials, determination of carbon, hydrogen and oxygen/metal ratio

    International Nuclear Information System (INIS)

    Jones, I.G.

    1976-02-01

    Equipment has been developed for the determination of carbon, hydrogen and oxygen/metal ratio on irradiated fuels, of carbon in stainless steel cladding materials and in graphite rich deposits, and of hydrogen in zircaloy. Carbon is determined by combustion to carbon dioxide which is collected and measured manometrically, hydrogen by vacuum extraction followed by diffusion through a palladium thimble, and oxygen/metal ratio by CO/CO 2 equilibration. A single set of equipment was devised in order to minimise the time and work involved in changing to a different set of equipment in a separate box, for each type of analysis. For each kind of analysis, alterations to the apparatus are involved but these can be carried out with the basic set in position in a shielded cell, although to do so it is necessary to obtain access via the gloves on the fibre-glass inner glove box. This requires a removal of samples emitting radiation, by transfer to an adjoining cell. A single vacuum system is employed. This is connected through a plug in the lead wall of the shielded cell, and couplings in the glove box wall to the appropriate furnaces. Carbon may be determined, in stainless steel containing 400 to 800 ppm C, with a coefficient of variation of +- 2%. On deposits containing carbon, the coefficient of variation is better than +- 1% for 2 to 30 mg of carbon. Hydrogen, at levels between 30 and 200 ppm in titanium can be determined with a coefficient of variation of better than +- 5%. Titanium has been used in lieu of zircaloy since standardised zircaloy specimens are not available. The precision for oxygen/metal ratio is estimated to be +- 0.001 Atoms oxygen. Sample weights of 200 mg are adequate for most analyses. (author)

  16. Suspended HOPG nanosheets for HOPG nanoresonator engineering and new carbon nanostructure synthesis

    International Nuclear Information System (INIS)

    Rose, F; Debray, A; Martin, P; Fujita, H; Kawakatsu, H

    2006-01-01

    Suspended highly oriented pyrolytic graphite (HOPG) nanosheets (10-300 nm thick) were created by direct mechanical cleavage of a bulk HOPG crystal onto silicon micropillars and microtracks. We show that suspended HOPG nanosheets can be used to engineer HOPG nanoresonators such as membranes, bridges, and cantilevers as thin as 28 carbon atom layers. We measured by Doppler laser heterodyne interferometry that the discrete vibration modes of an HOPG nanosheet membrane and the resonance frequency of a FIB-created HOPG microcantilever lie in the MHz frequency regime. Moreover, a new carbon nanostructure, named 'nanolace', was synthesized by focused ion beam (FIB) sputtering of suspended HOPG nanosheets. Graphite nanosheets suspended on micropillars were eroded by a FIB to create self-oriented pseudo-periodical ripples. Additional sputtering and subsequent milling of these ripples led to the formation of honeycomb-like shaped nanolaces suspended and linked by ribbons

  17. Nanostructured Diamond-Like Carbon Films Grown by Off-Axis Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Seong Shan Yap

    2015-01-01

    Full Text Available Nanostructured diamond-like carbon (DLC films instead of the ultrasmooth film were obtained by pulsed laser ablation of pyrolytic graphite. Deposition was performed at room temperature in vacuum with substrates placed at off-axis position. The configuration utilized high density plasma plume arriving at low effective angle for the formation of nanostructured DLC. Nanostructures with maximum size of 50 nm were deposited as compared to the ultrasmooth DLC films obtained in a conventional deposition. The Raman spectra of the films confirmed that the films were diamond-like/amorphous in nature. Although grown at an angle, ion energy of >35 eV was obtained at the off-axis position. This was proposed to be responsible for subplantation growth of sp3 hybridized carbon. The condensation of energetic clusters and oblique angle deposition correspondingly gave rise to the formation of nanostructured DLC in this study.

  18. Formation of tin-tin oxide core–shell nanoparticles in the composite SnO{sub 2−x}/nitrogen-doped carbon nanotubes by pulsed ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Korusenko, P.M., E-mail: korusenko@obisp.oscsbras.ru [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Nesov, S.N.; Bolotov, V.V.; Povoroznyuk, S.N. [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Pushkarev, A.I. [National Research Tomsk Polytechnic University, Lenin Ave. 2a, 634028 Tomsk (Russian Federation); Ivlev, K.E. [Omsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, Karl Marx avenue 15, 644040 Omsk (Russian Federation); Smirnov, D.A. [St. Petersburg State University, Lieutenant Shmidt Emb. 11, 198504 St. Petersburg (Russian Federation); Institute of Solid State Physics, Dresden University of Technology, D-01069 Dresden (Germany)

    2017-03-01

    Highlights: • Original method the formation of core–shell structures by pulsed ion beam is proposed. • The composite SnO{sub 2−x}/N-MWCNTs was irradiated by pulsed ion beam. • Morphology and electronic structure of the irradiated composite were characterized. • The formation of Sn−SnO{sub x} core–shell nanoparticles after irradiation was observed. - Abstract: The complex methods of transmission electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy were used to investigate the changes in the morphology, phase composition, and electronic structure of the composite SnO{sub 2−x}/nitrogen-doped multiwalled carbon nanotubes (SnO{sub 2−x}/N-MWCNTs) irradiated with the pulsed ion beam of nanosecond duration. The irradiation of the composite SnO{sub 2−x}/N-MWCNTs leads to the formation of nanoparticles with the core–shell structure on the surface of CNTs with a sharp interfacial boundary. It has been established that the “core” is a metal tin (Sn{sup 0}) with a typical size of 5–35 nm, and the “shell” is a thin amorphous layer (2–6 nm) consisting of nonstoichiometric tin oxide with a low oxygen content. The “core–shell” structure Sn−SnO{sub x} is formed due to the process of heating and evaporation of SnO{sub 2−x} under the effect of the ion beam, followed by vapor deposition on the surface of carbon nanotubes.

  19. Frictional property of glass-like carbon heat-treated at 1000-3000 deg. C

    International Nuclear Information System (INIS)

    Nakamura, Kazumasa; Sano, Takanori; Shindo, Hitoshi

    2008-01-01

    Frictional coefficient 'f' was measured in the air and in water at glass-like carbon (GLC) surfaces heat-treated between 1000 and 3000 deg. C. GLCs heat-treated at higher temperature had smoother and more hydrophobic faces, and lower f. The f was smaller than 0.10 for GLCs heat-treated at and above 2000 deg. C, which indicates their applicability as a solid lubricant or a self-lubricating material. The f = 0.06 observed for GLC heat-treated at 3000 deg. C was nearly the same as that of pyrolytic graphite (PG). Slightly lower f's were obtained in water than in the air

  20. Influences of Sr-90 beta-ray irradiation on electrical characteristics of carbon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kasani, H. [Department of Physics, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Taghi Ahmadi, M., E-mail: ahmadi1351@gmail.com [Nano-Technology Research Center, Nano-Electronic Group, Physics Department, Urmia University, 57147 Urmia (Iran, Islamic Republic of); Department of Electronics and Computer Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Khoda-bakhsh, R., E-mail: r.khodabakhsh16@gmail.com [Department of Physics, Faculty of Sciences, Urmia University, Urmia (Iran, Islamic Republic of); RezaeiOchbelagh, D. [Departments of Nuclear Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ismail, Razali [Department of Electronics and Computer Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia)

    2016-03-28

    This work is concerned with the low cost fabrication of carbon nanoparticles (CNPs), and its application to beta ray detection. The structural and morphological properties of the CNPs were obtained by spectral and microscopy techniques. A system based on CNPs application in the metal-semiconductor-metal (MSM) junction platform, which acts as a beta-ray (β-ray) sensor, is fabricated. The prototype is characterised by modelling, Monte Carlo simulation, and electrical investigations. Changes to the electrical behaviour of the proposed MSM system due to β-ray irradiation are validated by experimental results in both Ohmic and non-Ohmic (Schottky) contacts. The simulation was performed using the MCNPX code, which showed that most of the β-ray energies are deposited into CNPs and electrodes. However, in the Ohmic contact, because the β-ray is induced, the current of CNPs is decreased. The reduction of the current might be due to the change of the carrier properties by increasing the scattering of electrons. The current-density equation for electrons was employed for understanding the effects of β-ray in Ohmic contact of CNPs. On the contrary, in the Schottky contact case, CNPs current was increased with constant voltage when biased by β-ray irradiation. In this paper, the electron–hole generation using β-rays is dominant when compared to other significant effects of radiation exposure on semiconducting CNP-based Schottky contact. Hence, the current increment of CNPs can be justified by electron–hole generation in the depletion region.

  1. Studies of iron carbon alloys; Contribution a l'etude des alliages dilues de carbone dans le fer {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Anagnostopoulos, T [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1971-07-01

    Precipitation of carbon in {alpha} iron during a thermal treatment was followed using the magnetic after effect. A study was made of the influence of different parameters such as quenching speed, annealing rate, carbon concentration with or without impurity, irradiation effects. A transient sur-saturation occurs during dissolution of carbon in iron at 500 C. (author) [French] La precipitation du carbone dans le fer au cours d'un traitement thermique a ete suivie au moyen du trainage magnetique. L'etude de differents parametres tels que: vitesse de trempe, mode de recuit, concentration en carbone, presence d'impuretes, effet d'une irradiation, ont ete menes a bien. Un phenomene de sursaturation transitoire au cours de la remise en solution a 500 C a ete mis en evidence. (auteur)

  2. X-ray Analysis of Defects and Anomalies in AGR-5/6/7 TRISO Particles

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Skitt, Darren J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, John A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schumacher, Austin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Coated particle fuel batches J52O-16-93164, 93165, 93166, 93168, 93169, 93170, and 93172 were produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR), or may be used for other tests. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT lot J52R-16-69317 containing a mixture of 15.4%-enriched uranium carbide and uranium oxide (UCO), with the exception of Batch 93164, which used similar kernels from BWXT lot J52L-16-69316. The TRISO-coatings consisted of a ~50% dense carbon buffer layer with 100-μmnominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. Each coated particle batch was sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batch was designated by appending the letter A to the end of the batch number (e.g., 93164A). Secondary upgrading by sieving was performed on the upgraded batches to remove specific anomalies identified during analysis for Defective IPyC, and the upgraded batches were designated by appending the letter B to the end of the batch number (e.g., 93165B). Following this secondary upgrading, coated particle composite J52R-16-98005 was produced by BWXT as fuel for the AGR Program’s AGR-5/6/7 irradiation test in the INL ATR. This composite was comprised of coated particle fuel batches J52O-16-93165B, 93168B, 93169B, and 93170B.

  3. Theoretical Study of the Kinetics of the Pyrolytic Elimination Reaction of Ethyl Chloride

    Directory of Open Access Journals (Sweden)

    Isaiah Ajibade Adejoro

    2010-01-01

    Full Text Available The products of the gas-phase elimination of ethyl chloride are hydrogen chloride and ethane. Using AM1, MNDO and PM3 Hamiltonians of quantum mechanical computer code called MOPAC, a procedure for the kinetics and computation of the Arrhenius parameters for the pyrolytic elimination reaction of ethyl chloride was devised in order to evaluate the predictive ability of the three Hamiltonians used. The first-order rate coefficient for the three Hamiltonians are 1.15x10-8s-1, 4.55x10-15s-1 and 5.36x10-4s-1 for AM1, MNDO and PM3 respectively. The results obtained showed that the rate constant for the computed Arrhenius parameters compare well with the experimental values in the literature, thus showing that the computational procedure adequately simulates experimental results; also the semi-empirical AMI calculation has the best predictive ability with experiment followed by PM3 while MNDO has the least.

  4. Effects of γ- and x-irradiation upon activity and selectivity of a supported silver catalyst in the oxidation of ethylene and carbon monoxide

    International Nuclear Information System (INIS)

    Mora Vallejo, R.J.

    1975-01-01

    Effects of γ and x-radiation on catalytic selectivity of supported silver catalysts for production of ethylene oxide via ethylene oxidation were compared by determination of radio-induced changes in conversion-yield profiles. Influence of photon energy on the kinetics of the irradiation process was studied by determination of conversion-yield profiles, using samples of catalyst exposed to x-rays of different mean photon energy and γ-rays for different cumulative periods of time. The effect of γ-radiation on catalytic activity of the same silver catalysts for carbon monoxide oxidation was analyzed by determination of the reaction kinetics before and after catalyst irradiation

  5. Vulcanization of rubber mixtures by simultaneous electron beam and microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Martin, D. E-mail: martin@ifin.nipne.ro; Ighigeanu, D.; Mateescu, E.; Craciun, G.; Ighigeanu, A

    2002-08-01

    The comparative results obtained by applying separate electron beam (EB) irradiation and simultaneous EB and microwave (MW) irradiation to vulcanization of rubber mixtures based on natural rubber and polybutadiene rubber with carbon black are presented. In the absence of MW, EB irradiation doses of 200-250 kGy are required in order to obtain a higher vulcanization degree. The irradiation doses as well as irradiation times were markedly diminished, from 2 to 6 times, by simultaneous EB and MW irradiation.

  6. Thermal conductivity degradation of graphites due to neutron irradiation at low temperature

    International Nuclear Information System (INIS)

    Snead, L.L.; Burchell, T.D.

    1995-01-01

    Several graphites and carbon/carbon composites (C/C's) have been irradiated with fission neutrons near 150 C and at fluences up to a displacement level of 0.24 dpa. The unirradiated room temperature thermal conductivity of these materials varied from 114 W/m K for H-451 isotropic graphite, to 670 W/m K for a unidirectional FMI-1D C/C composite. At the irradiation temperature a saturation reduction in thermal conductivity was seen to occur at displacement levels of approximately 0.1 dpa. All materials were seen to degrade to approximately 10 to 14% of their original thermal conductivity after irradiation. The significant recovery of thermal conductivity due to post-irradiation isochronal anneals is also presented. (orig.)

  7. Effect of microwave irradiation on hydrogen sorption properties of hand mixed MgH{sub 2} – 10 wt.% carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Awad, A.S. [Université de Bordeaux, ICMCB-CNRS, 87 Avenue du Dr Schweitzer, F-33600 Pessac (France); LCPM/PR2N, Université Libanaise, Faculté des Sciences 2, 90656 Jdeidet El Matn (Lebanon); Nakhl, M.; Zakhour, M. [LCPM/PR2N, Université Libanaise, Faculté des Sciences 2, 90656 Jdeidet El Matn (Lebanon); Santos, S.F.; Souza, F.L. [Universidade Federal do ABC, Avenida dos Estados 5001, 09210-580 Santo André – SP (Brazil); Bobet, J.-L., E-mail: jean-louis.bobet@u-bordeaux.fr [Université de Bordeaux, ICMCB-CNRS, 87 Avenue du Dr Schweitzer, F-33600 Pessac (France)

    2016-08-15

    The effect of microwave (MW) irradiation on the hydrogen sorption properties of magnesium powder is explored in the present work. MgH{sub 2} – 10 wt.% CFs (CFs = Carbons Fibers) was prepared by hand mixing, dehydrogenated under microwave irradiation for 20 s and then hydrogenated/dehydrogenated at about 300 °C – 1 MPa and 330 °C–0.03 MPa to investigate the effect of microwave irradiation on the solid/gas sorption properties. It has to be noted that the hydrogen absorption capacity and sorption kinetics of the MgH{sub 2} – 10 wt.% CFs mixture increased after dehydriding under MW irradiation. The MgH{sub 2} – 10 wt.% CFs mixture dehydrogenated by microwave irradiation can absorb about 5.8 wt.% and 5.3 wt.% H at 330 and 300 °C, respectively, within 2 h while the as-prepared MgH{sub 2} – 10 wt.% CFs mixture absorb only 4.6 wt.% H within the same duration. It is also demonstrated that MgH{sub 2} – 10 wt.% CFs mixture dehydrogenated by microwave irradiation exhibited good hydrogen desorption properties and, as an example, a microwave irradiated sample could release 5.8 wt.% H within 1 h at 330 °C in comparison to the as-prepared MgH{sub 2} – 10 wt.% CFs mixture which desorbed 4.4 wt.% H within 3 h. Scanning electron microscopy (SEM) images revealed that the particle sizes of the MW dehydrogenated mixture decreased after several solid/gas sorption cycles. This contribute to the improvement of hydrogen storage properties of the microwaves dehydrogenated MgH{sub 2} – 10 wt.% CFs mixture. In addition, the hydrogenated MgH{sub 2} – 10 wt.% CFs mixture show reproducible and better microwave-assisted dehydriding reaction during second microwaves cycle. - Highlights: • Dehydriding reaction of MgH{sub 2} by microwave method. • Effect of microwaves treatment on the hydrogen sorption properties of Mg. • Effect of discontinuous microwaves irradiation.

  8. Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Alsabbagh, Ahmad, E-mail: ahalsabb@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Sarkar, Apu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Miller, Brandon [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Burns, Jatuporn [Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Squires, Leah; Porter, Douglas; Cole, James I. [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Murty, K.L. [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2014-10-06

    Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) have been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.37 dpa. Atom probe tomography revealed manganese and silicon-enriched clusters in both UFG and CG steel after neutron irradiation. Mechanical properties were characterized using microhardness and tensile tests, and irradiation of UFG carbon steel revealed minute radiation effects in contrast to the distinct radiation hardening and reduction of ductility in its CG counterpart. After irradiation, micro hardness indicated increases of around 9% for UFG versus 62% for CG steel. Similarly, tensile strength revealed increases of 8% and 94% respectively for UFG and CG steels while corresponding decreases in ductility were 56% versus 82%. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation while no significant change was observed in UFG steel, revealing better radiation tolerance. Quantitative correlations between experimental results and modeling were demonstrated based on irradiation induced precipitate strengthening and dislocation forest hardening mechanisms.

  9. Preparation of silica-supported carbon by Kraft lignin pyrolysis, and its use in solid-phase extraction of fluoroquinolones from environmental waters

    International Nuclear Information System (INIS)

    Speltini, Andrea; Sturini, Michela; Maraschi, Federica; Mandelli, Elettra; Dondi, Daniele; Profumo, Antonella; Vadivel, Dhanalakshmi

    2016-01-01

    The article describes a carbon-based material for solid-phase extraction (SPE) of fluoroquinolones from waters. It was obtained by pyrolytic deposition of Kraft lignin (LG) on silica particles. Marbofloxacin (MAR) and enrofloxacin (ENR) were chosen as model contaminants. The material was prepared by first adsorbing LG onto silica microparticles, this followed by pyrolytic treatment at 1200 °C for 2 h. Silica-supported carbon was characterized by scanning electron microscopy, surface area measurement (by BET), thermogravimetric analysis, and electron paramagnetic resonance. The carbon-coated silica particles were then tested as a column packing for SPE of MAR and ENR from spiked tap and river waters. Quantitative adsorption was observed at pH values of ∼7.5 for both drugs. They were eluted with a 70:30 mixture of aqueous tetrabutylammonium hydroxide and acetonitrile and then quantified by HPLC coupled to fluorescence detection. Samples spiked with MAR and ENR in the range from 10 to 1000 ng·L"−"1 gave recoveries ranging from 70 to 116% (for n = 3). Good inter-day precision (with RSDs between 7 and 16%) was observed for 20–1000 ng·L"−"1 spikes, also in natural river water. Sample volumes up to 500 mL provided enrichment factors up to 125, and this makes this material useful for determination of the two drugs at environmentally significant levels which are as low as a few ng·L"−"1. The batch-to-batch reproducibility was verified for 3 preparations. The sorbent was successfully applied to the determination of these drugs in environmental waters. (author)

  10. Synthesis of Au and Au/Cu alloy nanoparticles on multiwalled carbon nanotubes by using microwave irradiation

    International Nuclear Information System (INIS)

    Rangari, Vijaya K.; Dey, Sanchita; Jeelani, Shaik

    2010-01-01

    Gold nanoparticles and gold-copper alloy nanoparticles were synthesized by reduction of chloroauric acid (HAuCl_4.xH_2O) and co-reduction of chloroauric acid (HAuCl_4.xH_2O) and Copper(II) acetate [(CH_3COO)_2Cu.H_2O] by ethylene glycol through microwave irradiation technique. In this reaction ethylene glycol used as a solvent and also reducing agent. The cetyltrimethyl ammonium bromide (CTAB) used as surfactant. Au nanoparticles and Au-Cu nanoparticles on the surface of multiwalled carbon nanotube also produced by using same procedure. The XRD analysis confirmed the formation of Au and Au-Cu alloy nanoparticles on multiwalled carbon nanotubes(CNTs). The morphology and size of the particles were examined by the transmission electron microscopy. The EDS analysis on individual particles confirmed that the presence of two metals in a particle in case of alloy nanoparticle. The results presented here show that a variety of well defined metal and metal alloy nanoparticles can be produced by using the microwave polyol process with in a short period of time. (author)

  11. Preparation of nickel ferrite/carbon nanotubes composite by microwave irradiation technique for use as catalyst in photo-fenton reaction

    Energy Technology Data Exchange (ETDEWEB)

    Foletto, E.L.; Rigo, C.; Severo, E.C.; Mazutti, M.A.; Dotto, G.L.; Jahn, S.L.; Sales, J.C. [Universidade Federal de Santa Maria (UFSM), RS (Brazil); Chiavone-Filho, O. [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil); Gundel, A.; Lucchese, M. [Universidade Federal do Pampa (UNIPAMPA), Bage, RS (Brazil)

    2016-07-01

    Full text: Nickel ferrite/multi-walled carbon nanotubes (NiFe2O4/MWCNTs) composite has been rapidly synthesized via microwave irradiation technique. The structural properties of the formed product was investigated by X-ray diffraction (XRD), N2 adsorption/desorption isotherms, thermogravimetric analysis (TGA), Raman spectroscopy and, scanning electron microscopy (SEM). The catalytic behavior of composite material was evaluated by the degradation of Amaranth dye in the photo-Fenton reaction under visible light irradiation. The overall results showed that the prepared composite was successfully synthesized, demonstrating good performance in the dye degradation, with higher degradation rate compared to the NiFe2O4. The high efficiency in dye degradation can be attributed to synergism between NiFe2O4 and MWCNTs. Therefore, NiFe2O4/MWCNTs composite can be used as promising photo-Fenton catalyst to degrade Amaranth dye from aqueous solutions. (author)

  12. Glucose metabolism in gamma-irradiated rice seeds

    International Nuclear Information System (INIS)

    Inoue, M.; Hasegawa, H.; Hori, S.

    1980-01-01

    Gamma-irradiation of 30 kR in rice seeds caused marked inhibition in seedling growth, and prevented the release of reduced sugar during the period of 25 to 76hr after soaking. The C 6 /C 1 ratio following irradiation continued to decrease up to the 76th hour of soaking; the control's ratio tended to increase with comparable soaking time. The percentage recovery of 14 C in carbon dioxide from glucose -1- 14 C was lower in irradiated than in control seeds. These results indicate that gamma-irradiation reduces the participation of the pentose phosphate pathway in glucose catabolism during an early period of germination. (author)

  13. Enhancement of CNT-based filters efficiency by ion beam irradiation

    Science.gov (United States)

    Elsehly, Emad M.; Chechenin, N. G.; Makunin, A. V.; Shemukhin, A. A.; Motaweh, H. A.

    2018-05-01

    It is shown in the report that disorder produced by ion beam irradiation can enhance the functionality of the carbon nanotubes. The filters of pressed multiwalled carbon nanotubes (MWNTs) were irradiated by He+ ions of the energy E = 80 keV with the fluence 2 × 1016 ion/cm2. The removal of manganese from aqueous solutions by using pristine and ion beam irradiated MWNTs filters was studied as a function of pH, initial concentration of manganese in aqueous solution, MWNT mass and contact time. The filters before and after filtration were characterized by Raman (RS) and energy dispersive X-ray spectroscopy (EDS) techniques to investigate the deposition content in the filter and defect formation in the MWNTs. The irradiated samples showed an enhancement of removal efficiency of manganese up to 97.5% for 10 ppm Mn concentration, suggesting that irradiated MWNT filter is a better Mn adsorbent from aqueous solutions than the pristine one. Radiation-induced chemical functionalization of MWNTs due to ion beam irradiation, suggesting that complexation between the irradiated MWNTs and manganese ions is another mechanism. This conclusion is supported by EDS and RS and is correlated with a larger disorder in the irradiated samples as follows from RS. The study demonstrates that ion beam irradiation is a promising tool to enhance the filtration efficiency of MWNT filters.

  14. Effect of low temperature reactor irradiation on organic insulators in superconducting magnets, (4)

    International Nuclear Information System (INIS)

    Kato, Teruo; Takamura, Saburo

    1983-01-01

    In order to study effects of irradiation at low temperature on insulating materials of superconducting magnets, flexural and impact tests are carried out at 4.2K without warmup after low temperature irradiation for several fiber reinforced plastics. The used materials are glass fiber reinforced epoxies and polyimide, and carbon fiber reinforced epoxies. After irradiation of 1.1 X 10 9 rad, the reduction in flexural strength of G-10 CR is about 70% and that of G-11 CR about 25%. No change are observed in strength of glass fiber reinforced polyimide by low temperature irradiation. Other kinds of glass fiber reinforced epoxies show a reduction in strength but the flexural strength of carbon fiber reinforced epoxies increases a small by irradiation. Irradiation effect of these materials on impact value is similar to that on flexural strength. (author)

  15. The formation of hollow poly(methyl methacrylate)/multiwalled carbon nanotube nanocomposite cylinders by microwave irradiation

    International Nuclear Information System (INIS)

    Wang Huan; Hu Xijun; Ka Ming Ng; Feng Jiyun

    2009-01-01

    Poly(methyl methacrylate) (PMMA)/multiwalled carbon nanotube (MWCNT) nanocomposite particles with 1, 2 and 4 wt% of MWCNTs were prepared by mechanical grinding of PMMA and MWCNT powders in a mortar at room temperature. Both scanning electron microscopy and Raman scattering characterizations revealed that these nanocomposite particles consist of a PMMA core and a MWCNT shell. The PMMA/MWCNT nanocomposite particles were used to fabricate the corresponding nanocomposites in the form of a hollow cylinder with various diameters and heights under 700 W microwave irradiation within 1 min. A mechanism for the fast microwave assisted forming process is proposed. These experimental results may lead to a new technology for forming hollow polymeric articles that is different from the conventional injection and blowing process.

  16. The production of residual nuclides in Pb irradiated by 400 MeV/u carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ge, H.L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Ma, F., E-mail: mf@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, X.Y.; Ju, Y.Q.; Zhang, H.B.; Chen, L.; Luo, P. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, B. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Y.B.; Li, J.Y.; Xu, J.K. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liang, T.J. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S.L. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Yang, Y.W.; Yang, L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-10-15

    The experiment was performed by irradiating a Pb foil with 400 MeV/u carbon beam at the HIRFL-CSR in Lanzhou, China. The experimental data was acquired by the off-line γ-spectroscopy method. 32 radioactive residual nuclides had been observed and their cross sections were determined. The measured results were compared with the results simulated by Monte Carlo code MCNPX2.7.0. The comparison shows that the simulated cross sections were underestimated for the fragments from A = 20 to 41 and A = 110 to 175. By fitting the measured and simulated cross sections to Rudstams semi-empirical formula, it was found that the charge distribution of products was asymmetric for the residual nuclides with a high mass number.

  17. Wide variety of flower-color and -shape mutants regenerated from leaf cultures irradiated with ion beams

    International Nuclear Information System (INIS)

    Okamura, M.; Yasuno, N.; Ohtsuka, M.; Tanaka, A.; Shikazono, N.; Hase, Y.

    2003-01-01

    The efficiency of ion-beam irradiation combined with tissue culture in obtaining floral mutants was investigated and compared with those of gamma rays and X-rays in carnation. Leaf segments of carnation plants in vitro were irradiated with the 220 MeV carbon ions, and cultured till the shoot regenerated. The carbon ion had the highest effect in reducing the regeneration frequency, and the RBE value with respect to gamma-rays was four. The higher mutation frequency and the wider mutation spectrum were obtained in plants irradiated with the carbon ions than low LET radiations. Three new carnation varieties developed by ion-beam irradiation were applied for the registration of the Japanese Ministry of Agriculture, Forestry and Fisheries. The results indicate that ion beam irradiation could induce wide variety of flower-color and -shape mutants, and that the combined method of ion-beam irradiation with tissue culture is useful to obtain the commercial varieties in a short time

  18. dielectric constants of irradiated and carbonated polymers

    African Journals Online (AJOL)

    user

    1985-09-01

    Sep 1, 1985 ... These samples, with varying degrees of carbon concentration, are then exposed to infra-red rays from carbon arc lamp; ultraviolet rays from Hg discharge lamp and finally to x- rays. The exposure time is kept at approximately 20 minutes. Figure 1 shows the experimental arrangement for the measurement of.

  19. Carbon nanostructure formation driven by energetic particles

    International Nuclear Information System (INIS)

    Zhu Zhiyuan; Gong Jinlong; Zhu Dezhang

    2006-01-01

    Carbon nanostructures, especially carbon nanotubes (CNTs), have been envisaged to be the building blocks of a variety of nanoscale devices and materials. The inherent nanometer-size and ability of being either metallic or semiconductive of CNTs lead to their application in nanoelectronics. Excellent mechanical characteristics of CNTs suggest their use as structural reinforcements. However, to fully exploit the potential applications, effective means of tailoring CNT properties must be developed. Irradiation of materials with energetic particles beams (ions and electrons) is a standard and important tool for modifying material properties. Irradiation makes it possible to dope the samples, to create local amorphous region or vice versa, recrystallize the lattice and even drive a phase transition. In this paper, we report our results of (1) phase transfromation from carbon nanotubes to nanocrystalline diamond driven by hydrogen plasma, (2) onion-like nanostructure from carbon nanotubes driven by ion beams of several tens keV, and (3) amorphous carbon nanowire network formation by ion beam irradiation. Structural phase transformation from multiwalled carbon nanotubes to nanocrystalline diamond by hydrogen plasma post-treatment was carried out. Ultrahigh equivalent diamond nucleation density of more than 1011 nuclei/cm 2 was obtained. The diamond formation and growth mechanisms were proposed to be the consequence of the formation of sp3 bonded amorphous carbon clusters. The hydrogen chemisorption on curved graphite network and the energy deposited on CNTs by continuous impingement of activated molecular or atomic hydrogen are responsible for the formation of amorphous carbon matrix. Diamond nucleates and grows in the way similar to that of diamond chemical vapor deposition processes on amorphous carbon films. Furthermore, single crystalline diamond nanorods of 4-8 nm in diameter and up to 200 nm in length have been successfully synthesized by hydrogen plasma post

  20. The Birmingham Irradiation Facility

    International Nuclear Information System (INIS)

    Dervan, P.; French, R.; Hodgson, P.; Marin-Reyes, H.; Wilson, J.

    2013-01-01

    At the end of 2012 the proton irradiation facility at the CERN PS will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1×1 cm 2 ) silicon sensors

  1. The Birmingham Irradiation Facility

    CERN Document Server

    Dervan, P; Hodgson, P; Marin-Reyes, H; Wilson, J

    2013-01-01

    At the end of 2012 the proton irradiation facility at the CERN PS [1] will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1 x 1 cm^2 ) silicon sensors.

  2. The present situation of the irradiation application industry and irradiation facilities in Japan

    International Nuclear Information System (INIS)

    Mizusawa, K.; Baba, T.

    2003-01-01

    The irradiation application industry and irradiation facilities in Japan have been making slow but steady progress for the past 2-3 years. Beside conventional applications, new ones such as carbon fibers and membrane filters have come into the market. There are a lot of new applications about to emerge. PE tubing, already is in the European market, is being evaluated by end users in Japan. Cleaning of dioxin in exhaust gas was successfully tested at a pilot plant. Cross-linked PTFE and polyamide are waiting customers' evaluations as an engineering plastic. Surface cross-linking of artificial polycarbonate teeth has yielded remarkable experimental results. Cross-linking of polycaprolactone will be useful for biodegradable products. Being aware of the future growth of irradiation industry, contract service providers opened new facilities or increased their capability. Beside in-house facilities, there are now three Co-60 facilities and nine EB facilities available for contract irradiation in Japan

  3. p53-independent early and late apoptosis is mediated by ceramide after exposure of tumor cells to photon or carbon ion irradiation

    International Nuclear Information System (INIS)

    Alphonse, Gersende; Maalouf, Mira; Battiston-Montagne, Priscillia; Ardail, Dominique; Beuve, Michaël; Rousson, Robert; Taucher-Scholz, Gisela; Fournier, Claudia; Rodriguez-Lafrasse, Claire

    2013-01-01

    To determine whether ceramide is responsible for the induction of p53-independent early or late apoptosis in response to high- and low-Linear-Energy-Transfer (LET) irradiation. Four cell lines displaying different radiosensitivities and p53-protein status were irradiated with photons or 33.4 or 184 keV/μm carbon ions. The kinetics of ceramide production was quantified by fluorescent microscopy or High-Performance-Liquid-Chromatogaphy and the sequence of events leading to apoptosis by flow cytometry. Regardless of the p53-status, both low and high-LET irradiation induced an early ceramide production in radiosensitive cells and late in the radioresistant. This production strongly correlated with the level of early apoptosis in radiosensitive cells and delayed apoptosis in the radioresistant ones, regardless of radiation quality, tumor type, radiosensitivity, or p53-status. Inhibition of caspase activity or ceramide production showed that, for both types of radiation, ceramide is essential for the initiation of early apoptosis in radiosensitive cells and late apoptosis following mitotic catastrophe in radioresistant cells. Ceramide is a determining factor in the onset of early and late apoptosis after low and high-LET irradiation and is the mediator of the p53-independent-apoptotic pathway. We propose that ceramide is the molecular bridge between mitotic catastrophe and the commitment phase of delayed apoptosis in response to irradiation

  4. RBE of cells irradiated by carbon ions

    International Nuclear Information System (INIS)

    Li Wenjian; Zhou Guangming; Wei Zengquan; Wang Jufang; Dang Bingrong; Li Qiang; Xie Hongmei

    2002-01-01

    The mouse melanoma cells (B16), human cervical squamous carcinoma cells (HeLa), Chinese hamster pulmonary cells V79, and human hepatoma cells (SMMC-7721) were collected for studying. The cells of 5 x 10 5 /ml were seeded in 35 mm diameter petri dish and allowed to grow one day, and then the medium in petri dishes was removed away, the cells were washed once with phosphate-buffered saline (PBS), petri dishes was covered with 4μm thickness Mylar film. The cells were irradiated by 12 C ion beam with LETs of 125.5, 200, 700 keV/μm in water generated from HIRFL (Heavy Ion Research Facility in Lanzhou). For 60 Co γ-ray experiment, the cells of 5 x 10 4 /ml were grown in 20 ml culture flasks including 1.5 ml cell suspension and directly used for irradiation. Following irradiation, the cells were trypsinized, counted, plated at appropriate densities in growth medium and then seeded in 60 mm diameter culture dishes. Each dish was filled 4 ml standard medium, and incubated for 8-12 days at 37 degree C incubator containing 5% CO 2 . The cultures were then rinsed with PBS buffer at pH 6.8, fixed with Carnoy's fluid, stained for 8 min with Giemsa (1:20, pH 6.8), and colonies containing more than 50 cells were scored. Their relative biological effectivenesses (RBE) were investigated. The results show that RBE depends on cellular types and increases with increasing of cellular survival level when LET is at 125.5 keV/μm, and decreases with increasing LET when LET ≥ 125.5 keV/μm

  5. Suppression of carbon desorption from 4H-SiC by irradiating a remote nitrogen plasma at a low temperature

    Science.gov (United States)

    Shimabayashi, Masaharu; Kurihara, Kazuaki; Sasaki, Koichi

    2018-05-01

    We remotely irradiated a nitrogen plasma onto the carbon-side surface of 4H-SiC at a low temperature, and examined the effect of sample cooling on the characteristics of the nitride layer. An improved nitride layer, which had higher concentrations of carbon and silicon and a lower concentration of oxygen, was formed in the region at depths of more than 0.6–0.9 nm from the top surface. The depth of the fragile nitride layer in the top region, where no improved characteristics of the nitride layer were observed, became smaller with sample cooling. In addition, on the basis of the experimental results, we discussed the difference in the activation energy of the nitriding reaction of 4H-SiC supported by atomic nitrogen and molecular nitrogen in the metastable \\text{A}3Σ \\text{u} + state.

  6. Margin estimation and disturbances of irradiation field in layer-stacking carbon-ion beams for respiratory moving targets.

    Science.gov (United States)

    Tajiri, Shinya; Tashiro, Mutsumi; Mizukami, Tomohiro; Tsukishima, Chihiro; Torikoshi, Masami; Kanai, Tatsuaki

    2017-11-01

    Carbon-ion therapy by layer-stacking irradiation for static targets has been practised in clinical treatments. In order to apply this technique to a moving target, disturbances of carbon-ion dose distributions due to respiratory motion have been studied based on the measurement using a respiratory motion phantom, and the margin estimation given by the square root of the summation Internal margin2+Setup margin2 has been assessed. We assessed the volume in which the variation in the ratio of the dose for a target moving due to respiration relative to the dose for a static target was within 5%. The margins were insufficient for use with layer-stacking irradiation of a moving target, and an additional margin was required. The lateral movement of a target converts to the range variation, as the thickness of the range compensator changes with the movement of the target. Although the additional margin changes according to the shape of the ridge filter, dose uniformity of 5% can be achieved for a spherical target 93 mm in diameter when the upward range variation is limited to 5 mm and the additional margin of 2.5 mm is applied in case of our ridge filter. Dose uniformity in a clinical target largely depends on the shape of the mini-peak as well as on the bolus shape. We have shown the relationship between range variation and dose uniformity. In actual therapy, the upper limit of target movement should be considered by assessing the bolus shape. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  7. Structural evolution of defective graphene under heat treatment and gamma irradiation

    Science.gov (United States)

    Zhang, Yifei; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei; Liu, Liangsen; Zhao, Lihuan; Li, Jing; Jing, Miaolei

    2018-03-01

    We have studied the structural change of defective graphene built by annealing in different temperature under the condition of gamma irradiation. Firstly, we found the heat treatment not only reduced but also striped the graphene. This behavior made defects become more firstly and then become less with the increase of temperature. And then gamma irradiation removed some oxygen-containing groups, by a simultaneous changed over carbon in the graphitic lattice from sp3 to sp2. Also, the gamma irradiation decreased the interlayer spacing between graphene lowest to 3.391 Å and made a crosslink which resulting in the size of the ordered gaining. A variation was detected by Raman spectroscopy that the amorphous carbon was declined after gamma irradiation. Furtherly we found the degree of this decline raised first and then diminished with the increase in the number of defects. The change in repair capacity of gamma irradiation presented a strategy for repairing the defects of graphene.

  8. In situ synthesized Li2S@porous carbon cathode for graphite/Li2S full cells using ether-based electrolyte

    International Nuclear Information System (INIS)

    Wang, Ning; Zhao, Naiqin; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; He, Fang; Ma, Liying

    2017-01-01

    Graphical abstract: A facile method is proposed to prepare lithium sulfide@porous carbon composites (Li 2 S@PC) by in-situ reaction of lithium sulfate (Li 2 SO 4 ) and the pyrolytic carbon from glucose. We assembled graphite-Li 2 S@PC full-cells using the obtained Li 2 S@PC composites as the cathode, graphite as the anode and DOL/DME with LiNO 3 additive as the electrolyte. Display Omitted -- Highlights: •A simple synthesis method was proposed to form Li 2 S@porous carbon composites. •Graphite-Li 2 S full-cells were constructed in DME-based electrolyte. •A novel method was proposed to activate the full cells. -- Abstract: Lithium-sulfur (Li-S) batteries have been recognized as one of the promising next-generation energy storage devices owing to their high energy density, low cost and eco-friendliness. As for cathode’s performance, the main challenges for developing highly-efficient and long-life Li-S batteries are to retard the polysulfides diffusion into electrolyte and the reaction with metallic lithium (Li). Especially, the safety issues, derived from metallic Li in anode, must be overcome. Herein, we fabricated lithium sulfide@porous carbon composites (Li 2 S@PC) by an in-situ reaction between the lithium sulfate (Li 2 SO 4 ) and the pyrolytic carbon from glucose. The nanosized Li 2 S particles were uniformly distributed in the carbon matrix, which not only significantly improve electronic conductivity of the electrode but also effectively trap the dissolved polysulfides. Furthermore, on the basis of the graphite’s electrochemical features in ether-based electrolyte, we assembled graphite-Li 2 S@PC full cells using the obtained Li 2 S@PC composites as the cathode, graphite as the anode and the DOL/DME with LiNO 3 additive as the electrolyte. A unique strategy was proposed to activate the full-cells in descending order using constant voltage and current to charge the cut-off voltage. This Li-S full cell exhibits stable cycling performance at 0.5 C over

  9. Detection of irradiation history for health foods. Calcium salt of organic acid and its basic ingredient

    International Nuclear Information System (INIS)

    Sekiguchi, Masayuki; Nakagawa, Seiko; Yunoki, Shunji; Ohyabu, Yoshimi

    2013-01-01

    Calcium carbonate and calcium salt of organic acid are well-known food additives used for the improvement of the shelf life and eating quality of health food. Calcium carbonate is a precursor in the synthesis of calcium salts of organic acid. Certain calcium carbonates made of natural limestone mined from very old stratum have silicate minerals exposed to a low level of natural radiation over a long period of time and food additives derived from calcium carbonates contained of such silicate minerals are possible to classify as irradiated foods by PSL and TL analysis in spite of non-irradiation. The study of calcium carbonates and calcium salts of organic acid obtained from different producers were allow to provided appropriate decisions by using the information of both the TL response (Glow1 peak temperature and TL ratio) and PSL ratio. ESR measurements of radicals in such food additives caused by gamma- irradiation were effective tool for correctly determining for irradiation history of those because the measurements were not affected by silicate minerals contained in those. (author)

  10. Effects of irradiation and drying on volatile components of fresh shiitake (Lentinus edodes Sing)

    International Nuclear Information System (INIS)

    Yang, Ming-Sheng; Chyau, Charng-Cherng; Horng, Deng-Tsen; Yang, Jui-Sen

    1998-01-01

    Fresh shiitake (Lentinus edodes Sing) was irradiated with doses of 0.5, 1 and 2 kGy using 60 Co. Effects of γ-irradiation and drying on the volatile composition of shiitake were studied by gas chromatography (GC) and GC-mass spectrometry. Irradiation above 1.0 kGy could inhibit the growth and mould decay of fresh shiitakes after harvesting. Irradiation with 2 kGy increased the eight-carbon volatile components of fresh shiitake. Treatment at 1 kGy irradiation of fresh shiitake produced some new volatile compounds in the dry product, such as methylethyl disulphide, sulphinylbis methane, methyl(methylthio)ethyl disulphide and N-(3-methylbutyl) acetamide. The eight-carbon compounds mostly disappeared after drying. The amount of sulphur-containing volatile compounds in dried shiitake became lower during irradiation. Irradiation with doses of 1 or 2 kGy of fresh shiitake did not increase the volatile content of shiitake after drying

  11. Hot spots effect on infrared spectral luminance emitted by carbon under plasma particles impact

    International Nuclear Information System (INIS)

    Delchambre, E.; Reichle, R.; Mitteau, R.; Missirlian, M.; Gobin, R.

    2004-01-01

    During the last Tore Supra campaigns, an anomalous deformation in the near infrared spectrum of radiation has been observed on neutralizer underneath the Toroidal Pumped Limiter (TPL) on which we observed the growth of carbon layer. The consequence is the difficulty to asses the surface temperature of the components and the power loaded. Laboratory experiment has been performed, using an Electron Cyclotron Resonance (ECR) ions source, to reproduce, characterize and explain this phenomenon. The luminance emitted by Carbon Fibre Composite (CFC) and pyrolytic graphite, have been observed under 95 keV of H+ bombardments. The amplitude of the deformation was found to depend on the type of material used and the power density of the incident power loaded. This paper presents the possible hot spots explanation. The experimental luminance deformation is reproduced and these results are validated using a thermal model of dust in radiate equilibrium. (authors)

  12. Dosimetry of the portable blood irradiator

    International Nuclear Information System (INIS)

    Roberson, P.L.; Hungate, F.P.; Reece, W.D.; Tanner, J.E.

    1985-08-01

    A portable blood irradiator was developed at the Pacific Northwest Laboratory to evaluate the effects of chronic irradiation of the blood in suppressing graft rejection. The irradiator, designed to be worn on the arm or leg and be surgically connected in an arterio-venous shunt, uses beta radiation from activated thulium imbedded in a vitreous carbon matrix to reduce the number of lymphocytes circulating in the blood. The dose and energy spectra relative to the distance from and position around a prototype irradiator were measured by thermoluminescent dosimeters, ion chambers and photon spectroscopy. With computer simulations using those measurements, the shielding was redesigned to minimize the radiation dose to the patient and to the attending personnel and to minimize the weight of the irradiator. The new shielding design was incorporated into a new prototype, and the dose and spectral measurements were repeated, which confirmed the design improvements. 10 refs., 11 figs

  13. Bystander effects on mammalian cells induced by carbon ions

    International Nuclear Information System (INIS)

    Wang Jufang; Zhao Jing; Ma Qiufeng; Chinese Academy of Sciences, Beijing; Li Weijian; Zhou Guangming; Dang Bingrong; Mao Limin; Feng Yan

    2004-01-01

    Bystander effects on unirradiated V79 cells were observed by irradiated conditioned medium (ICM) method and co-cultured with carbon-ion-irradiated V79 cells. The results showed that the colony formation efficiency of unirradiated cells is obviously decreased by ICM. After co-culture with carbon-ion-irradiated cells for some time, the colony formation efficiency of co-cultured cells was lower than expected results assuming no bystander effects. The micronucleus frequency and hprt gene mutation rate was almost the same as expected results. Cytotoxic factor(s), which was effective for cell growth but not for micronucleus and mutation on unirradiated cells, might be released by irradiated cells. (authors)

  14. Femtosecond laser ablation of highly oriented pyrolytic graphite: a green route for large-scale production of porous graphene and graphene quantum dots

    Science.gov (United States)

    Russo, Paola; Hu, Anming; Compagnini, Giuseppe; Duley, Walter W.; Zhou, Norman Y.

    2014-01-01

    Porous graphene (PG) and graphene quantum dots (GQDs) are attracting attention due to their potential applications in photovoltaics, catalysis, and bio-related fields. We present a novel way for mass production of these promising materials. The femtosecond laser ablation of highly oriented pyrolytic graphite (HOPG) is employed for their synthesis. Porous graphene (PG) layers were found to float at the water-air interface, while graphene quantum dots (GQDs) were dispersed in the solution. The sheets consist of one to six stacked layers of spongy graphene, which form an irregular 3D porous structure that displays pores with an average size of 15-20 nm. Several characterization techniques have confirmed the porous nature of the collected layers. The analyses of the aqueous solution confirmed the presence of GQDs with dimensions of about 2-5 nm. It is found that the formation of both PG and GQDs depends on the fs-laser ablation energy. At laser fluences less than 12 J cm-2, no evidence of either PG or GQDs is detected. However, polyynes with six and eight carbon atoms per chain are found in the solution. For laser energies in the 20-30 J cm-2 range, these polyynes disappeared, while PG and GQDs were found at the water-air interface and in the solution, respectively. The origin of these materials can be explained based on the mechanisms for water breakdown and coal gasification. The absence of PG and GQDs, after the laser ablation of HOPG in liquid nitrogen, confirms the proposed mechanisms.Porous graphene (PG) and graphene quantum dots (GQDs) are attracting attention due to their potential applications in photovoltaics, catalysis, and bio-related fields. We present a novel way for mass production of these promising materials. The femtosecond laser ablation of highly oriented pyrolytic graphite (HOPG) is employed for their synthesis. Porous graphene (PG) layers were found to float at the water-air interface, while graphene quantum dots (GQDs) were dispersed in the

  15. Obtention of thermoluminescent efficiencies by means of irradiation of TLD-100 dosemeters with proton beams helium and carbon

    International Nuclear Information System (INIS)

    Avila, O.; Rodriguez V, M.; Aviles, P.; Gamboa de Buen, I.; Buenfil, A.E.; Ruiz T, C.; Brandan, M.E.

    2002-01-01

    In this work, the advances of a serial of measurements of relative efficiency thermoluminescent of heavy charged particles (PCP) with respect to gamma radiation for TLD-100, dosemeters of LiF: Mg,Ti manufactured by the Harshaw-Bicron company are reported. The PCP are essentials in the implementation of dosimetry associated with medical applications. The measurements before gamma radiation were carrying out using the Vickrad irradiator of the National Institute of Nuclear Research at dose of 1.663 Gy. The measures which are reported about protons, helium and carbon were realized using the Pelletron accelerator of the Physics Institute of the UNAM. (Author)

  16. Detection of gas-permeable fuel particles for highl 7490 temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Thiele, B.A.; Stinton, D.P.; Costanzo, D.A.

    1980-01-01

    Fuel for High-Temperature Gas-Cooled Reactors (HTGR) consists of uranium oxide-carbide and thoria microspheres coated with layers of pyrolytic carbon and silicon carbide. The pyrolytic carbon coatings must be gas-tight to perform properly during irradiation. Therefore, particles must be carefully characterized to determine the number of defective particles (ie bare kernels, and cracked or permeable coatings). Although techniques are available to determine the number of bare kernels or cracked coatings, no reliable technique has been available to measure coating permeability. This work describes a technique recently developed to determine whether coatings for a batch of particles are gas-tight or permeable. Although most of this study was performed on Biso-coated particles, the technique applies equally well to Triso-coated particles. About 150 randomly selected Biso-particle batches were studied in this work. These batches were first subjected to an 18-hr chlorination at 15000C, and the volatile thorium tetrachloride released through cracked or very permeable coatings was measured versus chlorination time. Chlorinated batches were also radiographed to detect any thorium that had migrated from the kernel into the coatings. From this work a technique was developed to determine coating permeability. This consists of an 18-hr chlorination of multiple samples without measurement of the heavy metal released. Each batch is then radiographed and the heavy metal diffusion within each particle is examined so it can be determined if a particle batch is permeable, slightly permeable, or gas-tight. (author)

  17. THE EFFECT OF APPLIED STRESS ON THE GRAPHITIZATION OF PYROLYTIC GRAPHITE

    Energy Technology Data Exchange (ETDEWEB)

    Bragg, R H; Crooks, D D; Fenn, Jr, R W; Hammond, M L

    1963-06-15

    Metallographic and x-ray diffraction studies were made of the effect of applied stress at high temperature on the structure of pyrolytic graphite (PG). The dominant factor was whether the PG was above or below its graphitization temperature, which, in turn, was not strongly dependent on applied stress. Below the graphitization temperature, the PG showed a high proportion of disordered layers (0.9), a fairly large mean tilt angle (20 deg ) and a small crystailite size (La --150 A). Fracture occurred at low stress and strain and the materiai exhibited a high apparent Young's modulus ( approximates 4 x 10/sup 6/ psi). Above the graphitization temperature, graphitization was considerably enhanced by strain up to about 8%. The disorder parameter was decreased from a zero strain value of 0.3 to 0.l5 with strain, the mean tilt angle was decreased to 4 deg , and a fivefold increase in crystallite size occurred. When the strainenhanced graphitization was complete, the material exhibited a low apparent modulus ( approximates 0.5 x 10/sup 6/ psi) and large plastic strains (>100%) for a constant stress ( approximates 55 ksi). Graphitization was shown to be a spontaneous process that is promoted by breaking cross-links thermally, and the process is furthered by chemical attack and plastic strain. (auth)

  18. Effect of gamma-irradiation on flavor compounds of fresh mushrooms

    International Nuclear Information System (INIS)

    Mau, J.L.; Hwang, S.J.

    1997-01-01

    Fresh mushrooms (Agaricus bisporus) were gamma-irradiated with doses of 1,2, and 5 kGy. The volatile compounds were isolated using a Lickens-Nickerson apparatus and analyzed using gas chromatography and gas chromatography-mass spectrometry. The amount of total volatiles was greatly affected by the doses applied. The amounts of benzaldehyde and benzyl alcohol were not affected by gamma-irradiation and ranged from 8.94 to 11.79 and from 0.696 to 1.503 micrograms/g, respectively. The amounts of eight-carbon compounds decreased as the doses of gamma-irradiation increased, from 41.73 for the control (0 kGy) to 20.06 (1 kGy), 8.77 (2 kGy), and 4.04 micrograms/g (5 kGy irradiated mushrooms). The major eight-carbon compound was 1-octen-3-ol, and its amount decreased from 30.34 (the control) to 14.18 (1 kGy), 6.22 (2 kGy), and 2.92 micrograms/g (5 kGy)

  19. Capsule HRB-15B postirradiation examination report

    International Nuclear Information System (INIS)

    Ketterer, J.W.; Bullock, R.E.

    1981-06-01

    Capsule HRB-15B design tested 184 thin graphite trays containing unbonded fuel particles to peak exposures of 6.6 x 10 25 n/m 2 (E > 29 fJ)/sub HTGR/ fast fluence, approx. 27% fissions per initial metal atom (FIMA) fissile burnup, and 6% FIMA fertile burnup at nominal time-averaged temperatures of 815 to 915 0 C. The capsule tested a variety of low-enriched uranium (approx. 19.5% U-235) fissile particle types, including UC 2 , UC/sub x/O/sub y/, UO 2 , zirconium-buffered UO 2 (referred to in this report as UO 2 /sup *), and 1:1(Th,U)O 2 with both TRISO and silicon-BISO coatings. All fertile particles were ThO 2 with BISO, silicon-BISO, or TRISO coatings. The findings indicated that all TRISO particles retained virtually all of their fission product inventories, except small quantities of silver, at these irradiation temperatures, while some of the silicon-BISO particles released significant amounts of both silver and cesium. No kernel migration, pressure vessel, or outer pyrolytic carbon (OPyC) failures were observed in the fuel particles, which had total diameters of 2 /sup */ particles exhibited no detrimental irradiation effects, but they contained pure carbon precipitates in the kernels after irradiation which were not observed in the undoped UO 2 particles. Postirradiation examination revealed no differences in the irradiation performance of three UC/sub x/O/sub y/ kernel types with varying oxygen/uranium ratios