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Sample records for electron beam irradiations

  1. Electron Beam Materials Irradiators

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.

    2012-06-01

    Radiation processing is a well established method for enhancing the properties of materials and commercial products by treating them with ionizing energy in the form of high-energy electrons, X-rays, and gamma rays. Beneficial effects include polymerizing, cross-linking, grafting and degrading plastics, sterilizing single-use medical devices, disinfecting and disinfesting fresh foods, purifying drinking water, treating wastewater and other toxic waste materials that harm the environment, and many other applications that are still being evaluated. Industrial electron accelerators of several types have been developed and are being used for these applications. More than 1800 electron accelerators are presently installed in facilities worldwide for these purposes.

  2. Green coffee decontamination by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Nemtanu, Monica R.; Brasoveanu, Mirela; Grecu, Maria Nicoleta; Minea, R.

    2005-10-01

    Microbiological load of green coffee is a real problem considering that it is extremely sensitive to contamination. Irradiation is a decontamination method for a lot of foodstuffs, being a feasible, very effective and environment friendly one. Beans and ground green coffee were irradiated with electron beams up to 40 kGy. Microbial load, rheological behavior, electron paramagnetic resonance (EPR) and visible spectroscopy were carried out. The results show that electron beam irradiation of green coffee could decontaminate it without severe changes in its properties.

  3. Electron beam irradiation of dental composites.

    PubMed

    Behr, Michael; Rosentritt, Martin; Faltermeier, Andreas; Handel, Gerhard

    2005-09-01

    Electron beam irradiation can be used to influence the mechanical properties of polymers. It was the aim of this study to investigate whether dental composites can benefit from irradiation in order to achieve increased fracture toughness, work of fracture, hardness or less wear. Two hundred rectangular specimens of five veneering composites were electron beam irradiated with 25, 100 and 200 kGy using an electron accelerator of 10 MeV. Fracture toughness, work of fracture, Vickers hardness, color changes and three-medium wear were measured and compared with non-irradiated specimens. Visible color changes (DeltaE>3) were observed with all composites and with all dose rates. Fracture toughness, work of fracture, Vickers hardness and resistance against wear increased significantly with few exceptions. Composites with a simple curing process needed higher dose rates while systems with a more complex curing procedure should be irradiated with lower dose rates. Electron beam irradiation can significantly change the mechanical properties of dental composites. However, color changes can limit the use of irradiation for dentistry.

  4. Electron beam irradiation of denture base materials.

    PubMed

    Behr, M; Rosentritt, M; Faltermeier, A; Handel, G

    2005-02-01

    Electron beam irradiation can be used to influence the properties of polymers. It was the aim of this study to investigate whether PMMA denture base materials can benefit from irradiation in order to have increased fracture toughness, work of fracture or hardness. Rectangular specimens of heat-and auto-curing denture base materials were electron beam irradiated (post-cured) with 25, 100 and 200 kGy using an electron acceleration of 10 MeV or 4.5 MeV respectively. Fracture toughness, work of fracture, Vickers hardness and colour changes were measured and compared with not-irradiated specimens. The toughness, work of fracture and hardness increased using 10 MeV with a dose of 25 kGy and with 100 kGy using 4.5 MeV. However, the clinical use may not benefit from the observed small changes. Higher dosage (200 kGy) decreased the values significantly. The colour changes reached a level which was found to be not clinically acceptable. PMMA denture base materials do not benefit from post-curing with electron beam irradiation.

  5. Electron beam irradiation modification of collagen membrane.

    PubMed

    Jiang, Bo; Wu, Zhihong; Zhao, Huichuan; Tang, Fangyuan; Lu, Jian; Wei, Qingrong; Zhang, Xingdong

    2006-01-01

    A critical observation of reconstituted collagen membrane radiated by electron beam (EB) indicated that these collagenous fibers become cross-linked network when the irradiation is carried out in greater than melt temperature and nitrogen atmosphere. Studies on the membrane properties showed that glass transformation temperature (Tg) and melt point (Tm) of reconstituted collagen have no changes, but thermal gravity curves and infrared (IR) spectra become obviously different before and after irradiation. Cross-linking density calculated by the equation based on the theory of Flory-Rehner proved further that the densities increase with radiation doses increasing. Resistance to enzymatic digestions in vitro and implantation in vivo were determined to evaluate the physicochemical properties of cross-linked matrices. Based on the above results, it was concluded that EB radiation inducing cross-linking in greater than melt temperature and nitrogen atmosphere condition is an attractive, effective method, which introduce into intermolecular covalent cross-linkings.

  6. Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroshi; Ikeda, Masayuki; Shimbo, Minoru; Miyano, Yasushi

    In this paper, the effects of the intensity of electron beam and the variation with time after irradiation of electron beam on the tensile strength of the polypropylene (PP), which is widely used as medicine containers, were investigated. PP with and without colorants were used first and samples irradiated under various intensity of EB. A tensile test on the irradiated samples with elapsed time after the irradiation of the electron beam was carried out. The effects of those factors on the tensile strength were discussed. The following results were obtained (1) The tensile strength of PP decreased due to the influence of the electron beam irradiation, however the rate of the decrease in strength was small compared with the original one. Furthermore, the rate of the decrease in strength was very small owing to the variation with time after the EB irradiation. (2) The tensile rupture strength of PP increased and the rupture strain owing to the influence of the electron beam irradiation compared with the original one. In addition, these rupture strength increased and the rupture strain decreased along with time after the irradiation of the electron beam. (3) The tensile rupture strain energy of PP decreased owing to the influence of the electron beam irradiation compared with the original one. In addition, the strain energy decreases with time after the irradiation of the electron beam. Moreover, the strength characteristics of PP with colorants received greater influence of electron beam compared with the one without colorants.

  7. Effect of electron beam irradiation on PMMA films

    SciTech Connect

    Tiwari, Pragya; Srivastava, A. K.; Khattak, B. Q.; Verma, Suveer; Upadhyay, Anuj; Sinha, A. K.; Ganguli, Tapas; Lodha, G. S.; Deb, S. K.

    2012-06-05

    Polymethyl methacrylate (PMMA) is characterized for electron beam interactions in the resist layer in lithographic applications. PMMA thin films (free standing) were prepared by solvent casting method. These films were irradiated with 30keV electron beam at different doses. Structural and chemical properties of the films were studied by means of X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy The XRD results showed that the amorphization increases with electron beam irradiation dose. FTIR spectroscopic analysis reveals that electron beam irradiation promotes the scission of carbonyl group and depletes hydrogen and converts polymeric structure into hydrogen depleted carbon network.

  8. Electron-beam irradiation of experimental denture base polymers.

    PubMed

    Faltermeier, Andreas; Behr, Michael; Rosentritt, Martin; Handel, Gerhard

    2007-06-01

    Since the properties of polymers can be influenced using electron-beam irradiation, the aim of this study was to investigate whether electron-beam post-curing can improve the mechanical properties of experimental denture base polymers. Rectangular specimens of different experimental polymeric blends were electron-beam irradiated (post-cured) with 25 kGy and 200 kGy using an electron accelerator of 4.5 MeV. Fracture toughness, work of fracture, Vickers hardness and colour changes were measured and compared in non-irradiated specimens. The mechanical properties of all the investigated polymers seemed to benefit from low-energy electron-beam irradiation (25 kGy). Using an energy dose of 200 kGy, all blends showed deteriorated mechanical properties resulting from chain breakage. Nevertheless, all investigated polymers had undesirable colour changes after electron-beam irradiation. Mechanical properties of experimental polymethyl-methacrylate could be changed using electron-beam irradiation. Because of discolorations caused by the irradiation levels investigated, these levels cannot be recommended for practical applications.

  9. Electron beam irradiated silver nanowires for a highly transparent heater.

    PubMed

    Hong, Chan-Hwa; Oh, Seung Kyu; Kim, Tae Kyoung; Cha, Yu-Jung; Kwak, Joon Seop; Shin, Jae-Heon; Ju, Byeong-Kwon; Cheong, Woo-Seok

    2015-12-07

    Transparent heaters have attracted increasing attention for their usefulness in vehicle windows, outdoor displays, and periscopes. We present high performance transparent heaters based on Ag nanowires with electron beam irradiation. We obtained an Ag-nanowire thin film with 48 ohm/sq of sheet resistance and 88.8% (substrate included) transmittance at 550 nm after electron beam irradiation for 120 sec. We demonstrate that the electron beam creates nano-soldering at the junctions of the Ag nanowires, which produces lower sheet resistance and improved adhesion of the Ag nanowires. We fabricated a transparent heater with Ag nanowires after electron beam irradiation, and obtained a temperature of 51 °C within 1 min at an applied voltage of 7 V. The presented technique will be useful in a wide range of applications for transparent heaters.

  10. Electron beam irradiated silver nanowires for a highly transparent heater

    PubMed Central

    Hong, Chan-Hwa; Oh, Seung Kyu; Kim, Tae Kyoung; Cha, Yu-Jung; Kwak, Joon Seop; Shin, Jae-Heon; Ju, Byeong-Kwon; Cheong, Woo-Seok

    2015-01-01

    Transparent heaters have attracted increasing attention for their usefulness in vehicle windows, outdoor displays, and periscopes. We present high performance transparent heaters based on Ag nanowires with electron beam irradiation. We obtained an Ag-nanowire thin film with 48 ohm/sq of sheet resistance and 88.8% (substrate included) transmittance at 550 nm after electron beam irradiation for 120 sec. We demonstrate that the electron beam creates nano-soldering at the junctions of the Ag nanowires, which produces lower sheet resistance and improved adhesion of the Ag nanowires. We fabricated a transparent heater with Ag nanowires after electron beam irradiation, and obtained a temperature of 51 °C within 1 min at an applied voltage of 7 V. The presented technique will be useful in a wide range of applications for transparent heaters. PMID:26639760

  11. Flue gas cleaning by multiple irradiation with electron beam

    NASA Astrophysics Data System (ADS)

    Paur, H.-R.; Baumann, W.; Mätzing, H.; Lindner, W.

    1995-09-01

    By electron beam treatment, NOx and SO2 can be reduced simultaneously from combustion flue gas. The efficiency of the process has been shown to improve by multiple irradiation. It appears most promising to perform the multiple irradiation with an intermediate gas scrubber. This paper reports experimental investigations on the efficiency of the intermediate filter.

  12. A compact low-energy electron beam irradiator.

    PubMed

    Cho, Sun Oh; Kim, Min; Lee, Byung Cheol; Jeong, Young Uk; Cha, In-su; Choi, Jeong-sik

    2002-05-01

    A new compact low-energy electron beam irradiator has been developed. The irradiator generates an electron beam to the air with energy variable from 35 to 80 keV and with a maximum current of 1 mA. The irradiation area is 30 x 30 mm2. A special irradiation port is developed for this low-energy irradiator. The electron beam is generated from a thermionic LaB6 cathode in vacuum. The beam is extracted to the air through a havar foil window. The thickness of the window is 4.8 microm, it is vacuum-tightly connected to the window to support by an indium wire. A controlled bow geometry of the window helps the thin window withstand the vacuum pressure. Cold air generated from a vortex tube cools down both the window and its support in order to prevent the window from melting down, due to beam energy dissipated in the foil. We found that about 60% of the beam current is extracted to the air at 80 keV.

  13. Electron beam irradiation of gemstone for color enhancement

    SciTech Connect

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A'iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi

    2012-09-26

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  14. Electron beam irradiation of gemstone for color enhancement

    NASA Astrophysics Data System (ADS)

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A'iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi

    2012-09-01

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  15. Reinforcing multiwall carbon nanotubes by electron beam irradiation

    SciTech Connect

    Duchamp, Martial; Meunier, Richard; Smajda, Rita; Mionic, Marijana; Forro, Laszlo; Magrez, Arnaud; Seo, Jin Won; Song, Bo; Tomanek, David

    2010-10-15

    We study the effect of electron beam irradiation on the bending modulus of multiwall carbon nanotubes grown by chemical vapor deposition. Atomic force microscopy observations of the nanotube deflection in the suspended-beam geometry suggest an internal, reversible stick-slip motion prior to irradiation, indicating presence of extended defects. Upon electron beam irradiation, nanotubes with an initial bending modulus exceeding 10 GPa initially get stiffer, before softening at high doses. Highly defective nanotubes with smaller initial bending moduli do not exhibit the initial reinforcement. These data are explained by ab initio molecular dynamics calculations suggesting a spontaneous cross-linking of neighboring nanotube walls at extended vacancy defects created by the electron beam, in agreement with electron microscopy observations. At low defect concentration, depending on the edge morphology, the covalent bonds between neighboring nanotube walls cause reinforcement by resisting relative motion of neighboring walls. At high concentration of defects that are present initially or induced by high electron beam dose, the structural integrity of the entire system suffers from increasing electron beam damage.

  16. Impact of electron beam irradiation on fish gelatin film properties.

    PubMed

    Benbettaïeb, Nasreddine; Karbowiak, Thomas; Brachais, Claire-Hélène; Debeaufort, Frédéric

    2016-03-15

    The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino acids. No modification of the crystallinity of the film is observed. These findings suggest that if structure changes, it only occurs in the amorphous phase of the gelatin matrix. It is also observed that irradiation enhances the thermal stability of the gelatin film, by increasing the glass transition temperature and the degradation temperature.

  17. Antimicrobial Activity and Stability of Electron Beam Irradiated Dental Irrigants

    PubMed Central

    Geethashri, A; Palaksha, K.J.; Sridhar, K. R.; Sanjeev, Ganesh

    2014-01-01

    Background: The electron beam (e-beam) radiation is considered as an effective means of sterilization of healthcare products as well as to induce the structural changes in the pharmaceutical agents/drug molecules. In addition to structural changes of pharmaceutical it also induces the formation of low molecular weight compounds with altered microbiological, physicochemical and toxicological properties. Among the several known medicaments, sodium hypochlorite (NaOCl) and chlorhexidine digluconate (CHX) are used as irrigants in dentistry to kill the pathogenic microorganisms like Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans inhabiting the oral cavity. Objectives: The aim of this study was to evaluate the antimicrobial activity and stability of e-beam irradiated dental irrigants, NaOCl and CHX. Materials and Methods: Two dental irrigants NaOCl (1.25% and 2.5%) and CHX (1% and 2%) were exposed to various doses of e-beam radiation. The antimicrobial activities of e-beam irradiated irrigants were compared with the non-irradiated (control) irrigants against E. faecalis, S. aureus, S. mutans and C. albicans by disc diffusion method. Following the storage, physico-chemical properties of the irrigants were recorded and the cytotoxic effect was evaluated on human gingival fibroblast cells. Result: The irrigants, 1.25% NaOCl and 1% CHX showed significantly increased antimicrobial activity against both E. faecalis, (16+0.0) and S. aureus (25+0.0) after irradiation with 1 kGy e-beam. Whereas, 2.5% NaOCl and 2% CHX showed slightly increased antimicrobial activity only against S. aureus (28+0.0). The significant difference was noticed in the antimicrobial activity and cytotoxicity of irradiated and non-irradiated irrigants following the storage for 180 d at 40C. Conclusion: The e-beam irradiation increased the antimicrobial activity of irrigants without altering the biocompatibility. PMID:25584220

  18. Characteristics of PVDF Membranes Irradiated by Electron Beam.

    PubMed

    Jaleh, Babak; Gavary, Negin; Fakhri, Parisa; Muensit, Nakatan; Taheri, Soheil Mohammad

    2015-01-05

    Polyvinylidene fluoride (PVDF) membranes were exposed vertically to a high energy electron beam (EB) in air, at room temperature. The chemical changes were examined by Fourier Transform Infrared Spectroscopy (FTIR). The surface morphologies were studied by Scanning Electron Microscopy (SEM) and showed some changes in the pore size. Thermogravimetric (TGA) analysis represented an increase in the thermal stability of PVDF due to irradiation. Electron paramagnetic resonance (EPR) showed the presence of free radicals in the irradiated PVDF. The effect of EB irradiation on the electrical properties of the membranes was analyzed in order to determine the dielectric constant, and an increase in the dielectric constant was found on increasing the dose. The surface hydrophilicity of the modified membrane was characterized by water contact angle measurement. The contact angle decreased compared to the original angle, indicating an improvement of surface hydrophilicity. Filtration results also showed that the pure water flux (PWF) of the modified membrane was lower than that of the unirradiated membrane.

  19. Electron Beam Irradiation of Cellulosic Materials—Opportunities and Limitations

    PubMed Central

    Henniges, Ute; Hasani, Merima; Potthast, Antje; Westman, Gunnar; Rosenau, Thomas

    2013-01-01

    The irradiation of pulp is of interest from different perspectives. Mainly it is required when a modification of cellulose is needed. Irradiation could bring many advantages, such as chemical savings and, therefore, cost savings and a reduction in environmental pollutants. In this account, pulp and dissociated celluloses were analyzed before and after irradiation by electron beaming. The focus of the analysis was the oxidation of hydroxyl groups to carbonyl and carboxyl groups in pulp and the degradation of cellulose causing a decrease in molar mass. For that purpose, the samples were labeled with a selective fluorescence marker and analyzed by gel permeation chromatography (GPC) coupled with multi-angle laser light scattering (MALLS), refractive index (RI), and fluorescence detectors. Degradation of the analyzed substrates was the predominant result of the irradiation; however, in the microcrystalline samples, oxidized cellulose functionalities were introduced along the cellulose chain, making this substrate suitable for further chemical modification. PMID:28809230

  20. Improvement in properties of plastic teeth by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Sano, Yuko; Ishikawa, Shun-ichi; Seguchi, Tadao

    2011-11-01

    Improvement of the comfort and esthetics of artificial plastic teeth is desirable for the recently increasing numbers of elderly in society. Plastic teeth made of polycarbonate (PC) were modified by electron beam (EB) irradiation under specific conditions, and the change in the chemical properties of the PC was investigated. The water absorption, glucose attachment, level of bis-phenol-A (BPA) extraction, maltose adhesion, and mucin adhesion on the PC teeth were measured before and after EB irradiation. EB irradiation to a dose of 3.5 kGy at 150 °C in a nitrogen gas atmosphere reduced the water absorption by 20%, glucose absorption by 40%, maltose adhesion by 20%, and the amount of various amino acids, formed as the hydrolysis products of mucin, adhering on the PC teeth were reduced by 60-99%. The BPA content was lower than the detection limit for analysis of both the original and the EB irradiated PC teeth.

  1. Ozone Production by Irradiation of Intense, Pulsed Relativistic Electron Beam

    NASA Astrophysics Data System (ADS)

    Imada, Go; Morishima, Nobuyuki; Yatsui, Kiyoshi

    Characteristics of ozone production have been investigated by irradiation of intense, pulsed relativistic electron beam (IREB). The 1.8-m-long gas-treatment chamber is filled up with dry-N2-balanced O2 gas mixture with the pressure of 98 kPa and is irradiated by IREB. The kinetic energy, current and pulse width of the IREB are - 2 MeV, - 2.9 kA, and - 80 ns (FWHM), respectively. It is found that - 340 ppm of ozone is produced by firing 10 shots of the IREB. We have also obtained the production yield of ozone of 9 - 21 g/kWh.

  2. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    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.

  3. Monitoring electron-beam irradiation effects on graphenes by temporal Auger electron spectroscopy.

    PubMed

    Xu, Mingsheng; Fujita, Daisuke; Hanagata, Nobutaka

    2010-07-02

    Because of its unique electronic transport properties, graphene has attracted an enormous amount of interest recently. By using standard Auger electron spectroscopy and Raman spectroscopy, we have studied electron-beam irradiation effects on graphene damage. We have shown that irradiation with an electron-beam can selectively remove graphene layers and induce chemical reactions, as well as possible structural transformations. We have also demonstrated the dependence of damage in graphene on electron-beam dose. Our work provides ideas on how to optimize the experimental conditions for graphene characterization and device fabrication. The results throw light on how energy transfer from the electron beam to graphene layers leads to the removal of carbon atoms from graphene layers and on the possibility of using electron-beam irradiation to locally induce chemical reactions in a controlled manner.

  4. Electron beam irradiation for biological decontamination of Spirulina platensis

    NASA Astrophysics Data System (ADS)

    Brasoveanu, Mirela; Nemtanu, Monica; Minea, R.; Grecu, Maria Nicoleta; Mazilu, Elena; Radulescu, Nora

    2005-10-01

    The Cyanobacterium Spirulina is commercialized for its use in health foods and for therapeutic purposes due to its valuable constituents particularly proteins and vitamins. The aim of the paper is to study the Spirulina platensis behaviour when it is electron beam irradiated for biological decontamination. Microbial load, antioxidant activity, enzymatic inhibition, electron spin resonance (ESR) and UV-Vis spectra were measured for doses up to 80 kGy. The results were correlated with doses in order to find where decontamination is efficient, keeping the Spirulina qualities.

  5. Effects of electron beam irradiation of cellulose acetate cigarette filters

    NASA Astrophysics Data System (ADS)

    Czayka, M.; Fisch, M.

    2012-07-01

    A method to reduce the molecular weight of cellulose acetate used in cigarette filters by using electron beam irradiation is demonstrated. Radiation levels easily obtained with commercially available electron accelerators result in a decrease in average molecular weight of about six-times with no embrittlement, or significant change in the elastic behavior of the filter. Since a first step in the biodegradation of cigarette filters is reduction in the filter material's molecular weight this invention has the potential to allow the production of significantly faster degrading filters.

  6. Electron beam irradiation stiffens zinc tin oxide nanowires.

    PubMed

    Zang, Jianfeng; Bao, Lihong; Webb, Richard A; Li, Xiaodong

    2011-11-09

    We report a remarkable phenomenon that electron beam irradiation (EBI) significantly enhances the Young's modulus of zinc tin oxide (ZTO) nanowires (NWs), up to a 40% increase compared with the pristine NWs. In situ uniaxial buckling tests on individual NWs were conducted using a nanomanipulator inside a scanning electron microscope. We propose that EBI results in substantial atomic bond contraction in ZTO NWs, accounting for the observed mechanically stiffening. This argument is supported by our experimental results that EBI also reduces the electrical conductivity of ZTO NWs.

  7. Vaccine Biotechnology by Accelerated Electron Beam and Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Togoe, Iulian I.; Tudor, Laurentiu M.; Martin, Diana I.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

    2007-04-01

    A new biotechnology for obtaining a commercial vaccine that contains either Fusobacterium necrophorum (F.n.) exotoxins inactivated by accelerated electron beam (EB) and microwave (MW) irradiation, or exotoxins isolated from F.n. cultures irradiated with EB+MW, is presented. This vaccine is designed for prophylaxis of ruminant infectious pododermatitis (IP) produced by F.n. Also, the research results concerning the effects of combined chemical adjuvant and EB+MW irradiation on F.n. immune capacity are discussed. The vaccine's efficacy will be tested in ruminant farms in which IP evolves. It is expected that this new vaccine to offer a better protection, more than 60%, which is the best presently obtained result in ruminant farms.

  8. Electron beam irradiation of Matricaria chamomilla L. for microbial decontamination

    NASA Astrophysics Data System (ADS)

    Nemţanu, Monica R.; Kikuchi, Irene Satiko; de Jesus Andreoli Pinto, Terezinha; Mazilu, Elena; Setnic, Silvia; Bucur, Marcela; Duliu, Octavian G.; Meltzer, Viorica; Pincu, Elena

    2008-05-01

    Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam irradiation.

  9. Sensor properties of electron beam irradiated fluorinated graphite

    NASA Astrophysics Data System (ADS)

    Sysoev, Vitalii I.; Gusel'nikov, Artem V.; Katkov, Mikhail V.; Asanov, Igor P.; Bulusheva, Lyubov G.; Okotrub, Alexander V.

    2016-03-01

    A graphene-like material was recovered through the reduction of initially nonconductive C2F graphite fluoride by irradiation with an electron beam with a kinetic energy of 500 eV. The surface conductivity increased by four orders of magnitude, and Raman scattering revealed a narrowing and redshift of the G mode peak. The samples were tested as a sensor material for detecting NO2 and NH3 molecules. After 25-min exposure to 1% NH3 and 0.5% NO2 at room temperature, the relative response of the sensor materials was 6 and 4%, respectively.

  10. Microbial Safety Improvement of Sea Buckthorn by Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Nemţanu, Monica R.; Minea, R.; Mazilu, Elena; Rǎdulescu, Nora

    2007-04-01

    The commercialization of medicinal plants and/or their products is highly increased in Romania lately. One of the most used herbs is sea buckthorn being well known for its quality with a large potential for curing some diseases. Sea buckthorn can be contaminated with undesirable microorganisms which may affect negatively its quality. The paper presents the results regarding the action of a non-conventional technology meaning electron beam technique on sea buckthorn in order to improve its microbiological quality. Our study revealed that the sea buckthorn microbial load has been improved after 3 kGy irradiation keeping its active principles.

  11. Microbial Safety Improvement of Sea Buckthorn by Electron Beam Irradiation

    SciTech Connect

    Nemtanu, Monica R.; Minea, R.; Mazilu, Elena; Radulescu, Nora

    2007-04-23

    The commercialization of medicinal plants and/or their products is highly increased in Romania lately. One of the most used herbs is sea buckthorn being well known for its quality with a large potential for curing some diseases. Sea buckthorn can be contaminated with undesirable microorganisms which may affect negatively its quality. The paper presents the results regarding the action of a non-conventional technology meaning electron beam technique on sea buckthorn in order to improve its microbiological quality. Our study revealed that the sea buckthorn microbial load has been improved after 3 kGy irradiation keeping its active principles.

  12. Deposition of silver on titania films by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Gu, Xue-Nan; Ye, Mao; Wu, Xiao-Ling; Wei, Lin; Hu, Yan; Hou, Xing-Gang; Liu, Xiao-Guang; Liu, An-Dong

    2006-06-01

    The deposition of silver on titania films prepared with sol-gel method was performed by electron beam irradiation of silver nitrate solutions. The high efficient Ag/TiO2 films were formed and exhibited enhanced photo-catalytic functions in degradation of methyl orange in aqueous solutions under UV illumination. Metallic Ag nano-clusters were confirmed by XPS, XRD and TEM. The relationship between the silver nitrate concentrations and the photo-catalytic efficiencies of the films was investigated. The optimum concentration of silver nitrate solution was found to be 5 × 10-4 M.

  13. Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

    2015-01-01

    Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

  14. Issues for Bringing Electron Beam Irradiators On-Line

    SciTech Connect

    Kaye, R.J.; Turman, B.N.

    1999-04-20

    Irradiation of red meat and poultry has been approved by the U.S. FDA, and the U.S. Department of Agriculture's rule for processing red meat is out for comment. Looking beyond the current issues of packaging materials, labeling, and consumer acceptance, this paper reviews the next step of implementation and how to remove, or at least reduce, the barriers to utilization. Polls of the user community identified their requirements for electron beam or x-ray processing of meat or poultry and their concerns about implementation for on-line processing. These needs and issues are compared to the capabilities of the accelerator industry. The critical issues of beam utilization and dose uniformity, factors affecting floor space requirements, and treatment costs are examined.

  15. Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays

    NASA Astrophysics Data System (ADS)

    Wang, Yuqing; Feng, Yi; Mo, Fei; Qian, Gang; Chen, Yangming; Yu, Dongbo; Wang, Yang; Zhang, Xuebin

    2014-07-01

    Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100 keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200 keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

  16. Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays

    SciTech Connect

    Wang, Yuqing; Feng, Yi Mo, Fei; Qian, Gang; Chen, Yangming; Yu, Dongbo; Wang, Yang; Zhang, Xuebin

    2014-07-14

    Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100 keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200 keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

  17. Treatment of effluents from petroleum production by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Duarte, Celina Lopes; Geraldo, Lucia Limoeiro; Junior, Oswaldo de Aquino P.; Borrely, Sueli Ivone; Sato, Ivone Mulako; Sampa, Maria Helena de Oliveira

    2004-09-01

    During the offshore oil production large volumes of aqueous waste with high salinity are produced. The produced water originates mainly from the oil-bearing formation but may also include seawater, which has been injected to maintain reservoir pressure. This water is normally separated from oil on the platform generating aqueous effluent with metals, sulfite, ammonium and organic compounds. The conventional treatment used includes filtration, flotation, ionic change and adsorption in activated charcoal, but the high salinity of this water decreases the treatment efficiency. The high efficiency of electron beam irradiation on removing organic compound in industrial effluent has been shown, and the primary aim of this study is to evaluate the efficiency of this new technology to treat the oil water production. Experiments were conducted using samples from two platforms processed in the radiation dynamics electron beam accelerator with 1.5 MeV energy and 37 kW power. The results showed that the electron beam technology has high efficiency in destroying organic compounds even in the presence of high salinity and complex effluent.

  18. An experimental investigation of wastewater treatment using electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Emami-Meibodi, M.; Parsaeian, M. R.; Amraei, R.; Banaei, M.; Anvari, F.; Tahami, S. M. R.; Vakhshoor, B.; Mehdizadeh, A.; Fallah Nejad, N.; Shirmardi, S. P.; Mostafavi, S. J.; Mousavi, S. M. J.

    2016-08-01

    Electron beam (EB) is used for disinfection and treatment of different types of sewage and industrial wastewater. However, high capital investment required and the abundant energy consumed by this process raise doubts about its cost-effectiveness. In this paper, different wastewaters, including two textile sewages and one municipal wastewater are experimentally studied under different irradiation strategies (i.e. batch, 60 l/min and 1000 m3/day) in order to establish the reliability and the optimum conditions for the treatment process. According to the results, EB improves the efficiency of traditional wastewater treatment methods, but, for textile samples, coagulation before EB irradiation is recommended. The cost estimation of EB treatment compared to conventional methods shows that EB has been more expensive than chlorination and less expensive than activated sludge. Therefore, EB irradiation is advisable if and only if conventional methods of textile wastewater treatment are insufficient or chlorination of municipal wastewater is not allowed for health reasons. Nevertheless, among the advanced oxidation processes (AOP), EB irradiation process may be the most suitable one in industrial scale operations.

  19. In situ formation of bismuth nanoparticles through electron-beam irradiation in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Sepulveda-Guzman, S.; Elizondo-Villarreal, N.; Ferrer, D.; Torres-Castro, A.; Gao, X.; Zhou, J. P.; Jose-Yacaman, M.

    2007-08-01

    In this work, bismuth nanoparticles were synthesized when a precursor, sodium bismuthate, was exposed to an electron beam at room temperature in a transmission electron microscope (TEM). The irradiation effects were investigated in situ using selected-area electron diffraction, high-resolution transmission electron microscopy and x-ray energy dispersive spectroscopy. After the electron irradiation, bismuth nanoparticles with a rhombohedral structure and diameter of 6 nm were observed. The average particle size increased with the irradiation time. The electron-induced reduction is attributed to the desorption of oxygen ions. This method offers a one-step route to synthesize bismuth nanoparticles using electron irradiation, and the particle size can be controlled by the irradiation time.

  20. Food Irradiation Using Electron Beams and X-Rays

    NASA Astrophysics Data System (ADS)

    Miller, Bruce

    2003-04-01

    In this presentation we will discuss the technology of food irradiation using electron accelerators. Food irradiation has generally come to describe the use of ionizing radiation to decrease the population of, or prevent the growth of, undesirable biological organisms in food. The many beneficial applications include insect disinfestation, sprouting inhibition, delayed ripening, and the enhanced safety and sterilization of fresh and frozen meat products, seafood, and eggs. With special regard to food safety, bacteria such as Salmonella enteridis, Listeria monocytogenes, Campylobacter jejuni and Escherichia coli serotype O157:H7 are the primary causes of food poisoning in industrialized countries. Ionizing doses in the range of only 1-5 kilogray (kGy) can virtually eliminate these organisms from food, without affecting the food's sensory and nutritional qualities, and without inducing radioactivity. The key elements of an accelerator-based irradiation facility include the accelerator system, a scanning system, and a material handling system that moves the product through the beam in a precisely controlled manner. Extensive radiation shielding is necessary to reduce the external dose to acceptable levels, and a safety system is necessary to prevent accidental exposure of personnel during accelerator operation. Parameters that affect the dose distribution must be continuously monitored and controlled with process control software. The choice of electron beam vs x-ray depends on the areal density (density times thickness) of the product and the anticipated mass throughput. To eliminate nuclear activation concerns, the maximum kinetic energy of the accelerator is limited by regulation to 10 MeV for electron beams, and 5 MeV for x-rays. From penetration considerations, the largest areal density that can be treated by double-sided electron irradiation at 10 MeV is about 8.8 g/cm2. Products having greater areal densities must be processed using more penetrating x-rays. The

  1. Effects of electron beam irradiation on polyamide 12 with fiberglass reinforcement

    SciTech Connect

    Jeun, Joon-Pyo; Shin, Bum-Sik; Kim, Hyun-Bin; Nho, Young-Chang; Kang, Phil-Hyun

    2010-06-02

    In the present study, the effects of electron beam irradiation of polyamide 12 (PA12) with fiberglass reinforcement on the thermal and wear properties were investigated. Electron beam irradiation of PA 12 was carried out over a range of irradiation doses (100-600 kGy) in air. The gel formation in the presence of a curing agent was dependent on the radiation doses. The thermal properties of irradiated PA 12 were studied in the temperature region 50-250 deg. C to observe the changes in the melting point with radiation dose. The dimensional stability was significantly increased by electron beam irradiation and the related crosslinking of the PA 12.

  2. Effects of electron beam irradiation on polyamide 12 with fiberglass reinforcement

    NASA Astrophysics Data System (ADS)

    Jeun, Joon-Pyo; Shin, Bum-Sik; Kim, Hyun-Bin; Nho, Young-Chang; Kang, Phil-Hyun

    2010-06-01

    In the present study, the effects of electron beam irradiation of polyamide 12 (PA12) with fiberglass reinforcement on the thermal and wear properties were investigated. Electron beam irradiation of PA 12 was carried out over a range of irradiation doses (100-600 kGy) in air. The gel formation in the presence of a curing agent was dependent on the radiation doses. The thermal properties of irradiated PA 12 were studied in the temperature region 50-250° C to observe the changes in the melting point with radiation dose. The dimensional stability was significantly increased by electron beam irradiation and the related crosslinking of the PA 12.

  3. The Irradiation Effect of a Simultaneous Laser and Electron Dual-beam on Void Formation

    PubMed Central

    Yang, Zhanbing; Watanabe, Seiichi; Kato, Takahiko

    2013-01-01

    Randomly distributed lattice point defects such as supersaturated vacancies (SVs) and Frenkel-pairs (FPs, an interstitial and a vacancy) can be simultaneously introduced into the crystal by energetic beam irradiation in outer space and/or nuclear reactors, but their behavior has not been fully understood. Using a high-voltage electron microscope equipped with a laser (laser-HVEM), we show the striking effects of simultaneous laser-electron (photon-electron) dual-beam irradiation on void formation. Our results reveal that during laser-electron sequential irradiation, pre-laser irradiation enhanced void nucleation and subsequent electron irradiation enhanced void growth. However, the laser-electron dual-beam irradiation was analyzed to depress void swelling remarkably because the recombination of SVs and interstitials was enhanced. The results provide insight into the mechanism underlying the dual-beam radiation-induced depression of void swelling in solids. PMID:23383371

  4. Modification of Ag containing photo-thermo-refractive glasses induced by electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Podsvirov, O. A.; Ignatiev, A. I.; Nashchekin, A. V.; Nikonorov, N. V.; Sidorov, A. I.; Tsekhomsky, V. A.; Usov, O. A.; Vostokov, A. V.

    2010-10-01

    We present the experimental investigation of formation and growth of Ag nanocrystals in silica photo-thermo-refractive glasses under the electron-beam irradiation and subsequent thermal treatment. The influence of electron irradiation fluence, current density and thermal treatment conditions on nanocrystal growth dynamic has been investigated. Theoretical models and computer simulation of main processes which take place during electron-beam irradiation are presented.

  5. Electrical properties of irradiated PVA film by using ion/electron beam

    NASA Astrophysics Data System (ADS)

    Abdelrahman, M. M.; Osman, M.; Hashhash, A.

    2016-02-01

    Ion/electron beam bombardment has shown great potential for improving the surface properties of polymers. Low-energy charged (ion/electron) beam irradiation of polymers is a good technique to modify properties such as electrical conductivity, structural behavior, and their mechanical properties. This paper reports on the effect of nitrogen and electron beam irradiation on the electrical properties of polyvinyl alcohol (PVA) films. PVA films of 4 mm were exposed to a charged (ion/electron) beam for different treatment times (15, 30, and 60 minutes); the beam was produced from a dual beam source using nitrogen gas with the other ion/electron source parameters optimized. The dielectric loss tangent tan δ , electrical conductivity σ , and dielectric constant ɛ ^' } in the frequency range 100 Hz-100 kHz were measured at room temperature. The variation of dielectric constant and loss tangent as a function of frequency was also studied at room temperature. The dielectric constant was found to be strongly dependent on frequency for both ion and electron beam irradiation doses. The real (ɛ ^' }) and imaginary (ɛ ^' ' }) parts of the dielectric constant decreased with frequency for all irradiated and non-irradiated samples. The AC conductivity showed an increase with frequency for all samples under the influence of both ion and electron irradiation for different times. Photoluminescence (PL) spectral changes were also studied. The formation of clusters and defects (which serve as non-radiative centers on the polymer surface) is confirmed by the decrease in the PL intensity.

  6. The influence of electron beam irradiation on fibre-reinforced composite specimens.

    PubMed

    Behr, M; Rosentritt, M; Dümmler, F; Handel, G

    2006-06-01

    This study investigated whether glass fibre-reinforced composite (FRC) specimens can benefit from post-curing using electron beam irradiation. Twenty-four frameworks of the Vectris and 24 of the Stick glass fibre-reinforced system were veneered with their correspondent veneer materials. Eight specimens of both systems were post-cured using electron beam irradiation (3 x 33 kGy, 10 MeV). The specimens were fixed in a restrained-end apparatus and inserted in an artificial mouth. With the exception of controls (n = 8 each) all other groups were thermally cycled and mechanically loaded (TCML). Finally, all samples were loaded to fracture using a universal testing machine. In two of eight non-irradiated Vectris/Targis specimens facing fracture occurred during TCML. Irradiation avoided these failures. No Stick/Sinfony facing fractured. However, Stick frameworks showed considerable torsions. Post-curing with electron beam irradiation made Stick frameworks stiffer. The fracture load of irradiated Stick/Sinfony specimens reached 520 +/- 31 N; control (without TCML and irradiation) 396 +/- 14 N, TCML-group without irradiation 362 +/- 41 N. Irradiated Vectris/Targis had a fracture resistance of 575 +/- 57 N; the control 556 +/- 36 N and the TCML group without irradiation 383 +/- 51 N. This investigation demonstrated that different types of FRC systems could considerably benefit from electron beam irradiation. The reconstructions became stiffer and resisted higher load.

  7. Biodegradability enhancement of textile wastewater by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Tak-Hyun; Lee, Jae-Kwang; Lee, Myun-Joo

    2007-06-01

    Textile wastewater generally contains various pollutants, which can cause problems during biological treatment. Electron beam radiation technology was applied to enhance the biodegradability of textile wastewater for an activated sludge process. The biodegradability (BOD 5/COD) increased at a 1.0 kGy dose. The biorefractory organic compounds were converted into more easily biodegradable compounds such as organic acids having lower molecular weights. In spite of the short hydraulic retention time (HRT) of the activated sludge process, not only high organic removal efficiencies, but also high microbial activities were achieved. In conclusion, textile wastewater was effectively treated by the combined process of electron beam radiation and an activated sludge process.

  8. The influence of electron beam irradiation on colour stability and hardness of aesthetic brackets.

    PubMed

    Faltermeier, Julia; Simon, Philipp; Reicheneder, Claudia; Proff, Peter; Faltermeier, Andreas

    2012-08-01

    Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100 kGy on the mechanical properties and colour stability of conventional polymer brackets and experimental filled composite brackets. The conventional brackets tested were Aesthetik-Line, Brillant, and Envision. The experimental brackets contained urethane dimethacrylate, as a monomer matrix and functional silane-treated SiO(2) fillers with a filler content of either 10 (Exper 1) or 40 (Exper 2) vol per cent. The influence of electron beam post-curing on Vickers hardness (VH) of the polymer brackets was investigated. Additionally, a possible discolouration of the brackets after electron beam irradiation was determined according to the three-dimensional L* a* b* colour space. The irradiated brackets were compared with untreated control groups. Statistical analysis was performed using the Wilcoxon test. With the exception of Brillant brackets, all investigated brackets showed a significant enhancement of VH after electron beam post-curing. However, the brackets suffered a significant increase in discolouration. Aesthetik-Line brackets showed the highest discolouration, ΔE, and Exper 2 brackets the lowest ΔE values. The discolouration of the examined brackets differed significantly. These results demonstrate that the mechanical properties of polymer brackets could be modified by electron beam irradiation. Nevertheless, clinical use of electron beam post-curing might be restricted because of unacceptable colour changes.

  9. The optical band gap and surface free energy of polyethylene modified by electron beam irradiations

    NASA Astrophysics Data System (ADS)

    Abdul-Kader, A. M.

    2013-04-01

    In this study, investigations have been carried out on electron beam irradiated ultra high molecular weight polyethylene (UHMWPE). Polyethylene samples were irradiated with 1.5 MeV electron beam at doses ranging from 50 to 500 kGy. Modifications in optical properties and photoluminescence behavior of the polymer were evaluated by UV-vis and photoluminescence techniques. Changes of surface layer composition of UHMWPE produced by electron irradiations were studied by Rutherford back scattering spectrometry (RBS). The change in wettability and surface free energy induced by irradiations was also investigated. The optical absorption studies reveal that both optical band gap and Urbach's energy decreases with increasing electron dose. A correlation between energy gap and the number of carbon atoms in clusters is discussed. Photoluminescence spectra were reveal remarkable decrease in the integrated luminescence intensity with increasing irradiation dose. Contact angle measurements showed that wettability and surface free energy increases with increasing the irradiation dose.

  10. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  11. Influence of electron beam and ultraviolet irradiations on graphene field effect transistors

    NASA Astrophysics Data System (ADS)

    Iqbal, Muhammad Zahir; Siddique, Salma; Anwar, Nadia

    2017-10-01

    Electrical transport properties of graphene can be modulated by different controlled doping methods in order to make it useful for practical applications. Here we report a comparative study of electron-beam (e-beam) irradiated and ultraviolet (UV) irradiated graphene field effect transistors (FETs) for different doses and exposure times. We observed red shift in Raman spectra of graphene under e-beam irradiation which represents n-type doping while a divergent trend has been identified for UV irradiations which signify p-type doping. These results are further confirmed by the electrical transport measurements where the Dirac point shifts towards negative backgate voltage (i.e. n-type doping) upon e-beam exposure and shifted towards positive backgate voltage (i.e. p-type doping) under ultraviolet irradiation. Our approach reveals the dual characteristics of graphene FETs under these irradiation environments.

  12. Morphological and structural modifications of multiwalled carbon nanotubes by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Elsehly, Emad M.; Chechenin, N. G.; Makunin, A. V.; Motaweh, H. A.

    2016-10-01

    Effects of electron beam irradiation on a morphology and structure of multiwalled carbon nanotubes sample in a normal imaging regime of a scanning electron microscope (SEM) were investigated. Direct SEM observations give evidence that irradiation by electron beam in SEM eliminates morphological unevenness, in the form of round spots of white contrast, on the surface of carbon nanotubes (CNTs) and makes the tubes thinner. Electron dispersive analysis and Raman spectroscopy are used to explore the origin and nature of these spots. From this analysis we found that e-beam irradiation improves the CNTs graphitization. The synergy of thermal heating and ionization produced by the irradiation are discussed as possible mechanisms of the observed effects.

  13. Mechanical and thermal properties of electron beam-irradiated polypropylene reinforced with Kraft lignin

    NASA Astrophysics Data System (ADS)

    Sugano-Segura, A. T. R.; Tavares, L. B.; Rizzi, J. G. F.; Rosa, D. S.; Salvadori, M. C.; dos Santos, D. J.

    2017-10-01

    Polypropylene reinforced with Kraft lignin composites (0, 2.5, 5.0 and 10.0 wt% lignin) were submitted to electron beam (EB) irradiation at doses of 0, 50, 100 and 250 kGy. Kraft lignin incorporation maintained Young´s modulus values, even at electron beam doses up to 100 kGy (10 wt% lignin). The yield stress losses were also reduced by the addition of lignin to polypropylene. Fourier transform infrared spectroscopy (FTIR) results showed low formation of carboxyl and hydroxyl groups for composites containing lignin. Dynamic mechanical analysis (DMA) curves indicated a synergistic effect between Kraft lignin and electron beam irradiation on the storage modulus (E´). Several properties evolved as a function of the Kraft lignin content. Synergistic effects between Kraft lignin incorporation and electron beam radiation contribute to applications that require the mechanical and thermal properties of iPP to be maintained, even after high doses of electron beam radiation.

  14. The impact of electron beam irradiation on Low density polyethylene and Ethylene vinyl acetate

    NASA Astrophysics Data System (ADS)

    Sabet, Maziyar; Soleimani, Hassan

    2017-05-01

    Improvement of measured gel content, hardness, tensile strength and elongation at break of Ethylene vinyl acetate (EVA) have confirmed positive effect of electron beam irradiation on EVA. Results obtained from both gel content tests show that degree of cross-linking in amorphous regions is dependent on dose. A significant improvement in tensile strength of neat EVA samples is obtained upon electron-beam radiation up to 210 kGy. Similarly, hardness properties of Low-density polyethylene (LDPE) improvewith increasing electron beam irradiation. This article deals with the impacts of electron beam (EB) irradiation on the properties of LDPE and Ethylene-Vinyl Acetate (EVA) as the two common based formulations for wire and cable applications.

  15. Application of electron-beam irradiation combined with antioxidants for fermented sausage and its quality characteristic

    NASA Astrophysics Data System (ADS)

    Lim, D. G.; Seol, K. H.; Jeon, H. J.; Jo, C.; Lee, M.

    2008-06-01

    The effects of various doses of electron-beam irradiation on the changes in microbiological attributes of fermented sausage and the combined effect of electron-beam irradiation and various antioxidants on the oxidative stability and sensory properties during cold storage were investigated. Results indicated that 2 kGy of irradiation was the most effective in manufacturing a fermented sausage, and the addition of rosemary extracts was effective in controlling the production of off-flavor and development of lipid oxidation during cold storage.

  16. In-situ synthesis of Ag nanoparticles by electron beam irradiation

    SciTech Connect

    Gong, Jiangfeng; Liu, Hongwei; Jiang, Yuwen; Yang, Shaoguang; Liao, Xiaozhou; Liu, Zongwen; Ringer, Simon

    2015-12-15

    Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber at room temperature and the growth mechanism was explored in detail. The sizes of the Ag nanoparticles are controlled by the electron beam current density. Two nanoparticle growth stages were identified. The first growth stage was dominated by the discharging effect, while the second stage was controlled by the heating effect. The nanoparticle synthesis method should be applicable to the synthesis of other metallic nanoparticles. - Highlights: • Ag nanoparticles were synthesized by electron beam irradiation in the transmission electron microscope chamber. • The sizes of the Ag nanoparticles are controlled by the electron beam current density. • The growth mechanism was studied, two growth stages were confirmed. • The first growth stage was dominated by the discharging effect, and the second stage was controlled by the heating effect.

  17. Effect of electron beam irradiation sterilization on the biomedical poly (octene-co-ethylene)/polypropylene films

    NASA Astrophysics Data System (ADS)

    Luan, Shifang; Shi, Hengchong; Yao, Zhanhai; Wang, Jianwei; Song, Yongxian; Yin, Jinghua

    2010-05-01

    The effect of electron beam irradiation with the dose ranging from 15 to 40 kGy on poly (octene-co-ethylene) (POE)/polypropylene (PP) films was investigated. Wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), yellowness index testing and mechanical performance measurement were applied to characterize the films. It demonstrated that crystalline structure exhibited little change, and degree of crystallinity slightly change under the irradiation treatment. Irradiation brought about oxidation of the films, forming hydroxyl groups of the peroxides and carbonyl groups. Tensile properties become worse as irradiation dose increased. Electron beam irradiation with the dose of 15-40 kGy has little effect on crystalline performance and a little influence for the POE/PP films, indicating a good irradiation resistance.

  18. Characterization of blend hydrogels based on plasticized starch/cellulose acetate/carboxymethyl cellulose synthesized by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Senna, Magdy M.; Mostafa, Abo El-Khair B.; Mahdy, Sanna R.; El-Naggar, Abdel Wahab M.

    2016-11-01

    Blend hydrogels based on aqueous solutions of plasticized starch and different ratios of cellulose acetate (CA) and carboxymethyl cellulose (CMC) were prepared by electron beam irradiation (EB). The blends before and after EB irradiation were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico-chemical properties of blend hydrogels prepared by electron beam irradiation were improved compared to unirradiated blends.

  19. Effect of electron-beam irradiation on graphene field effect devices

    NASA Astrophysics Data System (ADS)

    Childres, Isaac; Jauregui, Luis A.; Foxe, Michael; Tian, Jifa; Jalilian, Romaneh; Jovanovic, Igor; Chen, Yong P.

    2010-10-01

    Electron beam exposure is a commonly used tool for fabricating and imaging graphene-based devices. Here, we present a study of the effects of electron-beam irradiation on the electronic transport properties of graphene and the operation of graphene field-effect transistors (GFETs). Exposure to a 30 keV electron-beam caused negative shifts in the charge-neutral point (CNP) of the GFET, interpreted as due to n-doping in the graphene from the interaction of the energetic electron beam with the substrate. The shift in the CNP is substantially reduced for suspended graphene devices. The electron beam is seen to also decrease the carrier mobilities and minimum conductivity, indicating defects created in the graphene. The findings are valuable for understanding the effects of radiation damage on graphene and for the development of radiation-hard graphene-based electronics.

  20. Chemical patterning of Ag(111): Spatially confined oxide formation induced by electron beam irradiation

    SciTech Connect

    Guenther, S.; Reichelt, R.; Wintterlin, J.; Barinov, A.; Mentes, T. O.; Nino, M. A.; Locatelli, A.

    2008-12-08

    Low energy electron irradiation of a Ag(111) surface during NO{sub 2} adsorption at 300 K induces formation of Ag oxide. Using a spatially confined electron beam, small Ag{sub 2}O spots could be grown with a sharp, {approx}100 nm wide, boundary to the nonirradiated metallic surface. Since the structure size will mainly depend on the sharpness of the irradiating electron beam, this process has the potential of a single step nanostructuring process. Temperature treatment offers an easy way to manipulate the boundary between oxide and metallic silver by steering a chemical front.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Intraoperative electron beam irradiation for patients with unresectable pancreatic carcinoma

    SciTech Connect

    Shipley, W.U.; Wood, W.C.; Tepper, J.E.; Warshaw, A.L.; Orlow, E.L.; Kaufman, S.D.; Battit, G.E.; Nardi, G.L.

    1984-09-01

    Since 1978 we have used electron beam intraoperative radiation therapy (IORT) to deliver higher radiation doses to pancreatic tumors than are possible with external beam techniques while minimizing the dose to the surrounding normal tissues. Twenty-nine patients with localized, unresectable, pancreatic carcinoma were treated by electron beam IORT in combination with conventional external radiation therapy (XRT). The primary tumor was located in the head of the pancreas in 20 patients, in the head and body in six patients, and in the body and tail in three. Adjuvant chemotherapy was given in 23 of the 29 patients. The last 13 patients have received misonidazole (3.5 mg/M2) just prior to IORT (20 Gy). At present 14 patients are alive and 11 are without evidence of disease from 3 to 41 months after IORT. The median survival is 16.5 months. Eight patients have failed locally in the IORT field and two others failed regionally. Twelve patients have developed distant metastases, including five who failed locally or regionally. We have seen no local recurrences in the 12 patients who have been treated with misonidazole and have completed IORT and XRT while 10 of 15 patients treated without misonidazole have recurred locally. Because of the shorter follow-up in the misonidazole group, this apparent improvement is not statistically significant. Fifteen patients (52%) have not had pain following treatment and 22 (76%) have had no upper gastrointestinal or biliary obstruction subsequent to their initial surgical bypasses and radiation treatments. Based on the good palliation generally obtained, the 16.5-month median survival, and the possible added benefit from misonidazole, we are encouraged to continue this approach.

  3. Influence of electron-beam irradiation on bioactive compounds in grapefruits ( Citrus paradisi Macf.).

    PubMed

    Girennavar, Basavaraj; Jayaprakasha, G K; Mclin, Sara E; Maxim, Joe; Yoo, Kil Sun; Patil, Bhimanagouda S

    2008-11-26

    Phytochemical levels in fruits and vegetables can be affected by several postharvest factors. In the present study, the effect of electron-beam (E-beam) irradiation was studied on grapefruit bioactive compounds. 'Rio Red' and 'Marsh White' grapefruits were irradiated with E-beam at 0, 1.0, 2.5, 5.0, and 10.0 kGy. Changes of various bioactive compounds, such as vitamin C, flavonoids, carotenoids, furocoumarins, and limonoids, were measured. The acidity decreased slightly with an increasing E-beam dose, whereas the total soluble solids were increased. Irradiation did not affect the vitamin C content at 1 kGy; however, doses beyond 1 kGy significantly reduced the vitamin C content. Lycopene and beta-carotene did not change significantly from the irradiation. Lycopene levels decreased as the E-beam dose increased, while the beta-carotene content slightly increased. Dihydroxybergamottin levels exhibited a decreasing trend, while the bergamottin content did not change. Naringin, a major flavonoid of grapefruit, showed a significant increase over the control at 10 kGy in both 'Rio Red' and 'Marsh White'. Nomilin continued to decrease with an increasing dose of E-beam irradiation, while limonin levels remained the same at all of the doses. Low-dose E-beam irradiation has very little effect on the bioactive compounds and offers a safe alternative to existing postharvest treatments for the disinfection and decontamination of grapefruits.

  4. Ethylene-Propylene Terpolymer Rubber Processing by Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Manaila, Elena N.; Zuga, Maria Daniela T.; Martin, Diana I.; Craciun, Gabriela D.; Ighigeanu, Daniel I.; Matei, Constantin I.

    2007-04-01

    The investigations on the cross-linking by accelerated electrons of 6.23 MeV in lowly unsaturated elastomers of EPDM (ethylene-propylene terpolymer rubber) type are presented. Two rubber blends based EPDM were prepared and irradiated at different doses up to 250kGy: blend A - based on EPDM maleinized with polyethylene, zinc oxide, plasticizers, filler, and blend B - based on EPDM / PE (50 % EPDM and 50% polyethylene). Blends were prepared on a laboratory electrically heated rubber mill at temperatures of 150-160°C to enable the polyethylene (PE) melting to be reached. Plates of 150 × 150 × 2 mm were obtained in a laboratory electrical press at 170°C.

  5. Size-dependent crystalline fluctuation and growth mechanism of bismuth nanoparticles under electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Wu, Sujuan; Jiang, Yi; Hu, Lijun; Sun, Jianguo; Wan, Piaopiao; Sun, Lidong

    2016-06-01

    Advanced nanofabrication requires accurate tailoring of various nanostructures with the assistance of electron or ion beam irradiation. However, evolution of the nanostructures under the beam irradiation significantly affects the fabrication process. It is thus of paramount importance to study the evolution behaviors and growth mechanism of the nanostructures. In this study, bismuth nanoparticles were selected to investigate crystalline fluctuation under electron beam irradiation via transmission electron microscopy. The results disclose size-dependent crystalline fluctuation of the nanoparticles. The particles exhibit crystalline and non-crystalline features for sizes of above 15 and below 4 nm, respectively, while a mixture of the two states is observed with sizes in between. The crystalline fluctuation facilitates the growth process of the particles when a crystalline particle is in contact with another non-crystalline one. This is promising for applications in nanofabrication where high quality interfaces are desired between two joining parts.Advanced nanofabrication requires accurate tailoring of various nanostructures with the assistance of electron or ion beam irradiation. However, evolution of the nanostructures under the beam irradiation significantly affects the fabrication process. It is thus of paramount importance to study the evolution behaviors and growth mechanism of the nanostructures. In this study, bismuth nanoparticles were selected to investigate crystalline fluctuation under electron beam irradiation via transmission electron microscopy. The results disclose size-dependent crystalline fluctuation of the nanoparticles. The particles exhibit crystalline and non-crystalline features for sizes of above 15 and below 4 nm, respectively, while a mixture of the two states is observed with sizes in between. The crystalline fluctuation facilitates the growth process of the particles when a crystalline particle is in contact with another non

  6. Size-dependent crystalline fluctuation and growth mechanism of bismuth nanoparticles under electron beam irradiation.

    PubMed

    Wu, Sujuan; Jiang, Yi; Hu, Lijun; Sun, Jianguo; Wan, Piaopiao; Sun, Lidong

    2016-06-16

    Advanced nanofabrication requires accurate tailoring of various nanostructures with the assistance of electron or ion beam irradiation. However, evolution of the nanostructures under the beam irradiation significantly affects the fabrication process. It is thus of paramount importance to study the evolution behaviors and growth mechanism of the nanostructures. In this study, bismuth nanoparticles were selected to investigate crystalline fluctuation under electron beam irradiation via transmission electron microscopy. The results disclose size-dependent crystalline fluctuation of the nanoparticles. The particles exhibit crystalline and non-crystalline features for sizes of above 15 and below 4 nm, respectively, while a mixture of the two states is observed with sizes in between. The crystalline fluctuation facilitates the growth process of the particles when a crystalline particle is in contact with another non-crystalline one. This is promising for applications in nanofabrication where high quality interfaces are desired between two joining parts.

  7. An experience of electron beam (EB) irradiated gemstones in Malaysian nuclear agency

    NASA Astrophysics Data System (ADS)

    Idris, Sarada; Hairaldin, Siti Zulaiha; Tajau, Rida; Karim, Jamilah; Jusoh, Suhaimi; Ghazali, Zulkafli; Ahmad, Shamshad

    2014-02-01

    In Nuclear Malaysia, a study on gemstone irradiation using beta particle is conducted. The purpose of the study is to evaluate the gemstone colour enhancement by using different kind of precious and non-precious gemstones. By using irradiation technique, selected gemstones are exposed to highly ionizing radiation electron beam to knock off electrons to generate colour centres culminating in the introduction of deeper colours. The colour centres may be stable or unstable depending on the nature of colour centre produced. The colour change of irradiated stones were measured by HunterLab colour measurement. At 50 kGy, Topaz shows changes colour from colourless to golden. Meanwhile pearl shows changes from pale colour to grey. Kunzite and amethyst shows colour changes from colorless to green and pale colour to purple. Gamma survey meter measurement confirmed that irradiation treatment with 3 MeV electron beam machine does not render any activation that activate the gems to become radioactive.

  8. An experience of electron beam (EB) irradiated gemstones in Malaysian nuclear agency

    SciTech Connect

    Idris, Sarada Hairaldin, Siti Zulaiha Tajau, Rida Karim, Jamilah Jusoh, Suhaimi Ghazali, Zulkafli; Ahmad, Shamshad

    2014-02-12

    In Nuclear Malaysia, a study on gemstone irradiation using beta particle is conducted. The purpose of the study is to evaluate the gemstone colour enhancement by using different kind of precious and non-precious gemstones. By using irradiation technique, selected gemstones are exposed to highly ionizing radiation electron beam to knock off electrons to generate colour centres culminating in the introduction of deeper colours. The colour centres may be stable or unstable depending on the nature of colour centre produced. The colour change of irradiated stones were measured by HunterLab colour measurement. At 50 kGy, Topaz shows changes colour from colourless to golden. Meanwhile pearl shows changes from pale colour to grey. Kunzite and amethyst shows colour changes from colorless to green and pale colour to purple. Gamma survey meter measurement confirmed that irradiation treatment with 3 MeV electron beam machine does not render any activation that activate the gems to become radioactive.

  9. Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment

    PubMed Central

    Park, Sejoon; Yoo, Seung Hwa; Kang, Ha Ri; Jo, Seong Mu; Joh, Han-Ik; Lee, Sungho

    2016-01-01

    An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100–130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130–140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization. PMID:27349719

  10. Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment.

    PubMed

    Park, Sejoon; Yoo, Seung Hwa; Kang, Ha Ri; Jo, Seong Mu; Joh, Han-Ik; Lee, Sungho

    2016-06-28

    An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100-130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130-140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization.

  11. Comprehensive stabilization mechanism of electron-beam irradiated polyacrylonitrile fibers to shorten the conventional thermal treatment

    NASA Astrophysics Data System (ADS)

    Park, Sejoon; Yoo, Seung Hwa; Kang, Ha Ri; Jo, Seong Mu; Joh, Han-Ik; Lee, Sungho

    2016-06-01

    An electron beam was irradiated on polyacrylonitrile (PAN) fibers prior to thermal stabilization. The electron-beam irradiation effectively shortened the thermal stabilization process by one fourth compared with the conventional thermal stabilization process. A comprehensive mechanistic study was conducted regarding this shortening of the thermal stabilization by electron-beam irradiation. Various species of chain radicals were produced in PAN fibers by electron-beam irradiation and existed for a relatively long duration, as observed by electron spin resonance spectroscopy. Subsequently, these radicals were gradually oxidized to peroxy radicals in the presence of oxygen under storage or heating. We found that these peroxy radicals (CO) enabled such an effective shortcut of thermal stabilization by acting as intermolecular cross-linking and partial aromatization points in the low temperature range (100-130 °C) and as earlier initiation seeds of successive cyclization reactions in the next temperature range (>130-140 °C) of thermal stabilization. Finally, even at a low irradiation dose (200 kGy), followed by a short heat treatment (230 °C for 30 min), the PAN fibers were sufficiently stabilized to produce carbon fibers with tensile strength and modulus of 2.3 and 216 GPa, respectively, after carbonization.

  12. Nanopore integrated with Au clusters formed under electron beam irradiation for single molecule analysis

    NASA Astrophysics Data System (ADS)

    Choi, Seong Soo; Park, Myoung Jin; Han, Chul Hee; Kim, Sung In; Yoo, Jung Ho; Park, Kyung Jin; Park, Nam Kyou; Kim, Yong-Sang

    2016-02-01

    Recently the single molecules such as protein and deoxyribonucleic acid (DNA) have been successfully characterized using a solidstate nanopore with an electrical detection technique. However, the optical plasmonic nanopore has yet to be fabricated. The optical detection technique can be better utilized as next generation ultrafast geneome sequencing devices due to the possible utilization of the current optical technique for genome sequencing. In this report, we have investigated the Au nanopore formation under the electron beam irradiation on an Au aperture. The circular-type nanoopening with ~ 5 nm diameter on the diffused membrane is fabricated by using 2 keV electron beam irradiation by using field emission scanning electron microscopy (FESEM). We found the Au cluster on the periphery of the drilled aperture under a 2 keV electron beam irradiation. Immediately right after electron beam irradiation, no Au cluster and no Au crystal lattice structure on the diffused plane are observed. However, after the sample was kept for ~ 6 months under a room environment, the Au clusters are found on the diffused membrane and the Au crystal lattice structures on the diffused membrane are also found using high resolution transmission electron microscopy. These phenomena can be attributed to Ostwald ripening. In addition, the Au nano-hole on the 40 nm thick Au membrane was also drilled by using 200 keV scanning transmission electron microscopy.

  13. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    NASA Astrophysics Data System (ADS)

    Martin, Diana I.; Stan, Dana E.; Radu, Roxana R.; Cinca, Sabin A.; Margaritescu, Irina D.; Chirita, Doru I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

    2007-04-01

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  14. Pilot plant for flue gas treatment with electron beam -start up and two stage irradiation tests

    NASA Astrophysics Data System (ADS)

    Chmielewski, Andrzej G.; Tyminski, Bogdan; Licki, Janusz; Iller, Edward; Zimek, Zbigniew; Dobrowolski, Andrzej

    1993-10-01

    The pilot plant for flue gas treatment with electron beam has been built at Power Plant Kaweczyn, near Warsaw. The irradiation part of the pilot plant has been put in operation in 1991 whereas the complete installation including bag filter started to work in spring 1992. The starting tests consisted of studying the components reliability and influence of the two-stage irradiation process on efficiency of NO x removal. The results have shown that the two- stage irradiation leads to remarkable energy savings and retains high NO x removal. The mathematical models of the double and triple irradiation process are discussed.

  15. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    SciTech Connect

    Martin, Diana I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.; Stan, Dana E.; Radu, Roxana R.; Margaritescu, Irina D.; Chirita, Doru I.

    2007-04-23

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  16. Turning electrospun poly(methyl methacrylate) nanofibers into graphitic nanostructures by in situ electron beam irradiation

    SciTech Connect

    Duan, H. G.; Xie, E. Q.; Han, L.

    2008-02-15

    Using ultrathin electrospun poly(methyl methacrylate) (PMMA) nanofibers as precursor, graphitic nanofibers, nanobridges, nanocones, and fullerenelike onions could be prepared by electron beam irradiation in a controlled manner. With the help of the high resolution transmission electron microscopy, the real time processing of the carbonization and graphitization of the PMMA nanofibers could be investigated. This way to obtain graphitic nanostructures has promising applications in graphitic carbon nanostructure electronics and devices. Because PMMA is a widely used standard high resolution electron resist, this graphitization could be combined with electron beam lithography to obtain high resolution patterned graphitic circuits.

  17. Analysis of volatile organic compounds of ‘Fuji’ apples following electron beam irradiation and storage

    NASA Astrophysics Data System (ADS)

    Song, Hyun-Pa; Shim, Sung-Lye; Lee, Sun-Im; Kim, Dong-Ho; Kwon, Joong-Ho; Kim, Kyong-Su

    2012-08-01

    The volatile organic compounds of non-irradiated and electron-beam irradiated 'Fuji' apples (Malus domestica Borkh.) at 0, 0.5, and 1 kGy were isolated through simultaneous distillation extractions and analyzed using gas chromatograph-mass spectrometry. A total of 53 volatile organic compounds were characterized in 0 and 1 kGy irradiated samples, whereas two more compounds related to ketone and terpenoid group were identified in 0.5 kGy irradiated samples. The contents of volatile compounds were 24.33, 36.49, and 35.28 mg/kg in 0, 0.5, and 1 kGy irradiated samples, respectively. The major compounds identified were butanol, hexanal, [E]-2-hexenal, and hexanol in all samples. The relative content of alcohol increased after 30 days of storage in all samples, whereas that of aldehyde decreased. Although the contents of some volatile compounds were changed by electron-beam irradiation, the total yield and major flavor compounds of irradiated 'Fuji' apples were similar to, or even greater than, those of the control. Therefore, the application of e-beam irradiation if required for microbial decontamination of 'Fuji' apples is an acceptable method as it does not bring about any major quantitative changes of volatile organic compounds.

  18. Degradation of ampicillin in pig manure slurry and an aqueous ampicillin solution using electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Chung, Byung Yeoup; Kim, Jae-Sung; Lee, Min Hee; Lee, Kang Soo; Hwang, Seon Ah; Cho, Jae Young

    2009-07-01

    This study was carried out to evaluate the efficiency of degradation of antibiotic ampicillin in pig manure slurry and an aqueous ampicillin solution with the use of electron beam irradiation as a function of the absorbed dose. The degradation efficiency of ampicillin was close to 95% at an absorbed dose of 10 kGy. The degradation of ampicillin followed a "first-order" reaction rate with respect to absorbed dose. The results demonstrate that the electron beam irradiation technology is an effective means to remove antibiotics in manure and bodies of water.

  19. Radiation-Induced Centers in Lead Silicate Glasses Irradiated by Stationary and Pulsed Electron Beams

    NASA Astrophysics Data System (ADS)

    Zhidkov, I. S.; Zatsepin, A. F.; Konev, S. F.; Cholakh, S. O.

    2015-08-01

    Radiation-induced centers formed in heavy flint glasses irradiated by electron beams are investigated by the methods of optical and EPR spectroscopy. It is revealed that stable and short-living optical absorption centers of close natures are formed under irradiation by fast electrons. A correlation is established between the stable optical absorption bands and the EPR signals interpreted as signals of the (Pb2+)/h+ hole centers. The shortliving color centers are formed due to short-term distortion of the O-Pb bonds, and the stable centers are formed due to the spatial separation, thermalization, and subsequent stabilization of excited electrons and holes in tails of the localized states. Irradiation by electron beams leads to a change in the spectral characteristics of the fundamental absorption edge and, in particular, of the Urbach energy that determines the degree of structural disorder.

  20. Modeling the influence of electron beam irradiation on the heat resistance of Bacillus cereus spores.

    PubMed

    Valero, M; Sarrías, J A; Alvarez, D; Salmerón, M C

    2006-06-01

    The effect of electron beam irradiation (EBI) on Bacillus cereus spore heat resistance was investigated. Irradiation with accelerated electrons had an important heat-sensitizing effect on distilled-water spore suspensions. After irradiation doses of 1.3, 3.1, or 5.7 kGy followed by heating at 90 degrees C, calculated D(90)-values for strains Escuela Politécnica Superior de Orihuela (EPSO)-41WR and EPSO-50UR were reduced more than 1.3, 2.4, and 4.6 times, respectively. Plots of calculated log D(T)-values versus irradiation doses (1.3, 3.1, and 5.7 kGy) yielded straight parallel lines for the 85-100 degrees C heating temperature range, which made it possible to develop an equation to predict the changes in heat sensitivity of B. cereus spores that occurred with changing irradiation dose. Radiation-induced heat-sensitivity was characterized by a z(EBI)-value which was determined as the irradiation dose that should be required to reduce the decimal reduction time (D(T)) by one log(10) cycle when log(10)D(T) was plotted against irradiation treatment. A model is proposed to describe the influence of a pre-irradiation treatment with electron beams followed by heating on the heat resistance of B. cereus spores. This study also suggests the potential use of EBI followed by heating for food preservation.

  1. Effect of electron beam irradiation on thermal and mechanical properties of epoxy polymer

    NASA Astrophysics Data System (ADS)

    Nguyen, A. T.; Visakh, P. M.; Nazarenko, O. B.; Chandran, C. S.; Melnikova, T. V.

    2017-01-01

    This study investigates the thermal and mechanical properties of epoxy polymer after exposure to different doses of electron beam irradiation. The epoxy polymer was prepared using epoxy-diane resin ED-20 cured by polyethylenepolyamine. The irradiation of the samples was carried out with doses of 30, 100 and 300 kGy. The effects of doses on thermal and mechanical properties of the epoxy polymer were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The thermal properties of the epoxy polymer slightly increased after irradiation at the heating in air. The tensile strength and Young’s modulus of the epoxy polymer increased by the action of electron beam up to dose of 100 kGy and then decreased. The elongation at break decreased with increasing the irradiation dose.

  2. Structural and optical investigation of the effect of electron beam irradiation in a PM-355 nuclear track detector

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Bahammam, S.

    2012-05-01

    The effect of electron beam irradiation on the structure and optical properties of a PM-355 solid-state nuclear track detector has been investigated. Samples from PM-355 were irradiated with electron beams with different doses ranging from 20 to 250 kGy. The structural and optical modifications in the electron beam-irradiated PM-355 samples have been studied as a function of dose using different characterization techniques such as Fourier transform infrared spectroscopy, Vickers hardness, refractive index and color difference measurements. The Commission International de E'Claire (CIE units x, y and z) methodology was used in this work for the description of colored samples. In addition, the color differences between the non-irradiated sample and those irradiated with different electron beam doses were calculated. The results indicate that the PM-355 detector acquires color changes under electron beam irradiation.

  3. Fabrication of plasmonic nanopore by using electron beam irradiation for optical bio-sensor

    NASA Astrophysics Data System (ADS)

    Choi, Seong Soo; Park, Myoung Jin; Han, Chul Hee; Oh, Seh Joong; Park, Nam Kyou; Park, Doo Jae; Choi, Soo Bong; Kim, Yong-Sang

    2017-05-01

    The Au nano-hole surrounded by the periodic nano-patterns would provide the enhanced optical intensity. Hence, the nano-hole surrounded with periodic groove patterns can be utilized as single molecule nanobio optical sensor device. In this report, the nano-hole on the electron beam induced membrane surrounded by periodic groove patterns were fabricated by focused ion beam technique (FIB), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Initially, the Au films with three different thickness of 40 nm, 60 nm, and 200 nm were deposited on the SiN film by using an electron beam sputter-deposition technique, followed by removal of the supporting SiN film. The nanopore was formed on the electron beam induced membrane under the FESEM electron beam irradiation. Nanopore formation inside the Au aperture was controlled down to a few nanometer, by electron beam irradiations. The optical intensities from the biomolecules on the surfaces including Au coated pyramid with periodic groove patterns were investigated via surface enhanced Raman spectroscopy (SERS). The fabricated nanopore surrounded by periodic patterns can be utilized as a next generation single molecule bio optical sensor.

  4. New electron beam facility for irradiated plasma facing materials testing in hot cell

    SciTech Connect

    Sakamoto, N.; Kawamura, H.; Akiba, M.

    1995-09-01

    Since plasma facing components such as the first wall and the divertor for the next step fusion reactors are exposed to high heat loads and high energy neutron flux generated by the plasma, it is urgent to develop of plasma facing components which can resist these. Then, we have established electron beam heat facility ({open_quotes}OHBIS{close_quotes}, Oarai Hot-cell electron Beam Irradiating System) at a hot cell in JMTR (Japan Materials Testing Reactor) hot laboratory in order to estimate thermal shock resistivity of plasma facing materials and heat removal capabilities of divertor elements under steady state heating. In this facility, irradiated plasma facing materials (beryllium, carbon based materials and so on) and divertor elements can be treated. This facility consists of an electron beam unit with the maximum beam power of 50kW and the vacuum vessel. The acceleration voltage and the maximum beam current are 30kV (constant) and 1.7A, respectively. The loading time of electron beam is more than 0.1ms. The shape of vacuum vessel is cylindrical, and the mainly dimensions are 500mm in inner diameter, 1000mm in height. The ultimate vacuum of this vessel is 1 x 10{sup -4}Pa. At present, the facility for thermal shock test has been established in a hot cell. And performance estimation on the electron beam is being conducted. Presently, the devices for heat loading tests under steady state will be added to this facility.

  5. The evaluation of 6 and 18 MeV electron beams for small animal irradiation

    NASA Astrophysics Data System (ADS)

    Chao, T. C.; Chen, A. M.; Tu, S. J.; Tung, C. J.; Hong, J. H.; Lee, C. C.

    2009-10-01

    A small animal irradiator is critical for providing optimal radiation dose distributions for pre-clinical animal studies. This paper focuses on the evaluation of using 6 or 18 MeV electron beams as small animal irradiators. Compared with all other prototypes which use photons to irradiate small animals, an electron irradiator has many advantages in its shallow dose distribution. Two major approaches including simulation and measurement were used to evaluate the feasibility of applying electron beams in animal irradiation. These simulations and measurements were taken in three different fields (a 6 cm × 6 cm square field, and 4 mm and 30 mm diameter circular fields) and with two different energies (6 MeV and 18 MeV). A PTW Semiflex chamber in a PTW-MP3 water tank, a PTW Markus chamber type 23343, a PTW diamond detector type 60003 and KODAK XV films were used to measure PDDs, lateral beam profiles and output factors for either optimizing parameters of Monte Carlo simulation or to verify Monte Carlo simulation in small fields. Results show good agreement for comparisons of percentage depth doses (<=2.5% for 6 MeV e; <=1.8% for 18 MeV e) and profiles (FWHM <= 0.5 mm) between simulations and measurements on the 6 cm field. Greater deviation can be observed in the 4 mm field, which is mainly caused by the partial volume effects of the detectors. The FWHM of the profiles for the 18 MeV electron beam is 32.6 mm in the 30 mm field, and 4.7 mm in the 4 mm field at d90. It will take 1-13 min to complete one irradiation of 5-10 Gy. In addition, two different digital phantoms were also constructed, including a homogeneous cylindrical water phantom and a CT-based heterogeneous mouse phantom, and were implemented into Monte Carlo to simulate dose distribution with different electron irradiations.

  6. Valence photoelectron spectra of an electron-beam-irradiated C60 film

    NASA Astrophysics Data System (ADS)

    Onoe, Jun; Nakao, Aiko; Hida, Akira

    2004-10-01

    Valence photoelectron spectra of an electron-beam (EB) irradiated C60 film, which exhibited metallic electron-transport properties in air at room temperature, are presented. The electronic structure of the C60 film became closer to that of graphite as the EB-irradiation time increased, and its density of states around the Fermi level was eventually greater than for the graphite. This suggests that the electronic structure of the C60 film changed from a semiconductor to a semimetal and/or metal by EB irradiation. Interestingly, the electronic structure remained metallic even after five days of air exposure, which is the reason for the metallic electron-transport property in our previous report [Appl. Phys. Lett. 82, 595 (2003)].

  7. Electron-beam irradiation induced conductivity in ZnS nanowires as revealed by in situ transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Liu, Baodan; Bando, Yoshio; Wang, Mingsheng; Zhi, Chunyi; Fang, Xiaosheng; Tang, Chengchun; Mitome, Masanori; Golberg, Dmitri

    2009-08-01

    Electron transport variations in individual ZnS nanowires synthesized through a chemical vapor deposition process were in situ studied in transmission electron microscope under convergent electron-beam irradiation (EBI). It was found that the transport can dramatically be enhanced using proper irradiation conditions. The conductivity mechanism was revealed based on a detailed study of microstructure and composition evolutions under irradiation. EBI-induced Zn-rich domains' appearance and related O doping were mainly responsible for the conductivity improvements. First-principles theoretical calculations additionally indicated that the generation of midbands within a ZnS band gap might also contribute to the improved conductivity.

  8. Enhancement of biodegradability of real textile and dyeing wastewater by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    He, Shijun; Sun, Weihua; Wang, Jianlong; Chen, Lvjun; Zhang, Youxue; Yu, Jiang

    2016-07-01

    A textile and dyeing wastewater treatment plant is going to be upgraded due to the stringent discharge standards in Jiangsu province, China, and electron beam irradiation is considering to be used. In order to determine the suitable location of the electron accelerator in the process of wastewater treatment plant, the effects of electron beam (EB) irradiation on the biodegradability of various real wastewater samples collecting from the different stages of the wastewater treatment plant, the values of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and the ratio of BOD5 and COD (BOD5/COD), were compared before and after EB irradiation. During EB irradiation process, color indices and absorbance at 254 nm wavelength (UV254) of wastewater were also determined. The results showed that EB irradiation pre-treatment cannot improve the biodegradability of raw textile and dyeing wastewater, which contains a large amount of biodegradable organic matters. In contrast, as to the final effluent of biological treatment process, EB irradiation can enhance the biodegradability to 224%. Therefore, the promising way is to apply EB irradiation as a post-treatment of the conventional biological process.

  9. Coexisting ferroelectric and paraelectric phases in electron beam irradiated P(VDF-TrFE) films

    NASA Astrophysics Data System (ADS)

    Kim, Jae Woong; Lee, Tae Kwon; Jung, Jong Hoon; Shin, Sunhyeop; Lee, Byoung Wan; Ko, Jae-Hyeon

    2016-12-01

    We report on structural, electrical, and Raman investigations of phase changes induced in P(VDF-TrFE) films by electron beam irradiation. With increasing electron beam dose, the ferroelectric β-phase is weakened because of reductions in the coercive field, remnant polarization, and Curie temperature. Finally, highly dosed (9.38 × 1016 cm-2) P(VDF-TrFE) shows a paraelectric α-phase. A Vogel-Folcher type relaxor behavior becomes strong with the decreasing freezing temperature and the increasing activation energy. From the Raman scattering measurement, we observed that both the α- and the β-phases coexist irrespective of the electron beam irradiation and that the temperature dependences of the α- and β-phases are quite different. The ratio of the intensity of the α-phase to that of the β-phase sharply increases at a certain temperature, at which polar nanoregions may disappear.

  10. Dielectric-thickness dependence of damage induced by electron-beam irradiation of MNOS gate pattern

    NASA Astrophysics Data System (ADS)

    Matsui, Miyako; Mine, Toshiyuki; Hozawa, Kazuyuki; Watanabe, Kikuo; Inoue, Jiro; Nagaishi, Hiroshi

    2007-03-01

    We analyzed the electron-irradiation damage induced by electron-beam inspection of MNOS capacitors with various gate-dielectric thicknesses. Damage induced in a MNOS capacitor with SiON dielectric for high-performance CMOS devices was compared with that induced on a MOS capacitor with SiO II dielectric. We found that there is no remarkable difference between the damage to MOS capacitors and that to MNOS capacitors. The induced damage strongly depends on the thickness of the gate dielectric. Damages were induced when a higher-energy electron-beam, whose electron range was larger than the thickness of the gate electrode, was irradiated. When the electron beam was irradiated to a MOS capacitor with gate-dielectric thickness of 10.0 nm the flat-band-voltage shifted due to the created traps. When the electron beam was scanned to a MOS or MNOS capacitor with gate-dielectric thickness of 4.0 nm, Vfb shifted by less than 6 mV. However, the leakage-current density increased to 10 -7 A/cm2 at gate-electrode voltage of 3.0 V. On the other hand, when the electron beam was scanned on a MNOS capacitor with 2.5-nm-thick SiON dielectric, even the leakage current density was not increased. Accordingly, for damage-free inspection when gate-dielectric thickness is 4.0 nm or more, the electron-beam energy should be lower so that the electron range is smaller than the thickness of the gate electrode.

  11. Oxidation and disorder in few-layered graphene induced by the electron-beam irradiation

    SciTech Connect

    Xu Zhiwei; Wang Rui; Qian Xiaoming; Chen Lei; Li Jialu; Song Xiaoyan; Liu Liangsen; Chen Guangwei

    2011-05-02

    Structural changes caused by an electron beam with the high irradiation energy of 5 MeV were investigated in few-layered graphene. Both the original and the irradiated few-layered graphene were characterized by x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy. It was found that a typical diffraction peak of graphene oxide emerged and this may be attributed to a partial oxidation in few-layered graphene which was induced by the irradiation. In addition, the graphitic structure of few-layered graphene was found to be disordered according to the increased intensity ratio of D to G band.

  12. Monte Carlo simulation on a gold nanoparticle irradiated by electron beams.

    PubMed

    Chow, James C L; Leung, Michael K K; Jaffray, David A

    2012-06-07

    This study investigated the secondary electron production from a gold nanoparticle (GNP) irradiated by monoenergetic electron beams using Monte Carlo (MC) simulation. Spherical GNPs with diameters of 2, 50 and 100 nm in water were irradiated by monoenergetic electron beams with energies equal to 50 keV, 250 keV, 1 MeV and 4 MeV. MC simulations were performed using the Geant4 toolkit to determine the energy of the secondary electrons emitted from the GNPs. The mean effective range and deflection angle of the secondary electrons were tracked. Energy depositions inside and outside the nanoparticles due to the secondary electrons were also calculated. For comparisons, simulations were repeated by replacing the GNPs with water. Our results show that the mean effective range of secondary electrons increased with an increase of the GNP size and electron beam energy. For the electron beam energy and GNP size used in this study, the mean effective range was 0.5-15 µm outside the nanoparticle, which is approximately within the dimension of a living cell. The mean deflection angles varied from 78 to 83 degrees as per our MC results. The proportion of energy deposition inside the GNP versus that outside increased with the GNP size. This is different from the results obtained from a previous study using photon beams. The secondary electron energy deposition ratio (energy deposition for GNP/energy deposition for water) was found to be highest for the smallest GNP of 2 nm diameter in this study. For the energy deposited by the secondary electron, we concluded that the addition of GNPs can increase the secondary electron energy deposition in water, though most of the energy was self-absorbed by the large nanoparticles (50 and 100 nm). In addition, an electron source in the presence of GNPs does not seem to be better than photons as the yield of secondary electrons per unit mass of gold is less than water.

  13. Effect of electron-beam irradiation on antimicrobial, antibiofilm activity, and cytotoxicity of mouth rinses.

    PubMed

    Geethashri, A; Kumar, B Mohana; Palaksha, K J; Sridhar, K R; Sanjeev, Ganesh; Shetty, A Veena

    2016-01-01

    Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron-beam (E-beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E-beam in irradiated mouth rinses were evaluated for its biological activities. The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O'Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3-(4, 5 Dimethythiazol-yl)-2,5-Diphenyl-tetrazolium bromide assay. Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P< 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P< 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P< 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose- and species-dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy.xs The E-beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.

  14. Determination of the displacement energy of O, Si and Zr under electron beam irradiation

    SciTech Connect

    Edmondson, Philip D; Weber, William J; Namavar, Fereydoon; Zhang, Yanwen

    2012-01-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  15. Effect of Electron-Beam Irradiation on Organic Semiconductor and Its Application for Transistor-Based Dosimeters.

    PubMed

    Kim, Jae Joon; Ha, Jun Mok; Lee, Hyeok Moo; Raza, Hamid Saeed; Park, Ji Won; Cho, Sung Oh

    2016-08-03

    The effects of electron-beam irradiation on the organic semiconductor rubrene and its application as a dosimeter was investigated. Through the measurements of photoluminescence and the ultraviolet photoelectron spectroscopy, we found that electron-beam irradiation induces n-doping of rubrene. Additionally, we fabricated rubrene thin-film transistors with pristine and irradiated rubrene, and discovered that the decrease in transistor properties originated from the irradiation of rubrene and that the threshold voltages are shifted to the opposite directions as the irradiated layers. Finally, a highly sensitive and air-stable electron dosimeter was fabricated based on a rubrene transistor.

  16. Directed fast electron beams in ultraintense picosecond laser irradiated solid targets

    SciTech Connect

    Ge, X. L.; Lin, X. X.; Yuan, X. H. E-mail: ytli@iphy.ac.cn; Sheng, Z. M.; Carroll, D. C.; Neely, D.; Gray, R. J.; Tresca, O.; McKenna, P.; Yu, T. P.; Chen, M.; Liu, F.; Zhuo, H. B.; Zielbauer, B.; and others

    2015-08-31

    We report on fast electron transport and emission patterns from solid targets irradiated by s-polarized, relativistically intense, picosecond laser pulses. A beam of multi-MeV electrons is found to be transported along the target surface in the laser polarization direction. The spatial-intensity and energy distributions of this beam are compared with the beam produced along the laser propagation axis. It is shown that even for peak laser intensities an order of magnitude higher than the relativistic threshold, laser polarization still plays an important role in electron energy transport. Results from 3D particle-in-cell simulations confirm the findings. The characterization of directional beam emission is important for applications requiring efficient energy transfer, including secondary photon and ion source development.

  17. Remotion of organic compounds of actual industrial effluents by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Sampa, M. H. O.; Duarte, C. L.; Rela, P. R.; Somessari, E. S. R.; Silveira, C. G.; Azevedo, A. L.

    1998-06-01

    Organic compounds has been a great problem of environmental pollution, the traditional methods are not effecient on removing these compounds and most of them are deposited to ambient and stay there for long time causing problems to the environment. Ionizing radiation has been used with success to destroy organic molecules. Actual industrial effluents were irradiated using IPEN's electron beam wastewater pilot plant to study organic compounds degradation. The samples were irradiated with and without air mixture by different doses. Irradiation treatment efficiency was evaluated by the Cromatography Gas Analyses of the samples before and after irradiation. The studied organic compounds were: phenol, chloroform, tetrachloroethylene (PCE), carbon tetrachloride, trichloroethylene (TCE), 1,1-dichloroethane, dichloromethane, benzene, toluene and xilene. A degradation superior to 80% was achieved for the majority of the compounds with air addition and 2kGy delivered dose condition. For the samples that were irradiated without air addition the degradation was higher.

  18. Mechanical performance of electron-beam-irradiated UHMWPE in vacuum and in air.

    PubMed

    Visco, A M; Torrisi, L; Campo, N; Emanuele, U; Trifirò, A; Trimarchi, M

    2009-04-01

    Ultrahigh molecular weight polyethylene (UHMWPE) was modified by a 5-MeV energy electron beam at different temperatures before, during, and after irradiation, both in air and in high vacuum. Wear resistance, hardness, and tensile strength of irradiated polyethylene were compared with those of untreated one. Physical analyses (like infrared spectroscopy and calorimetric analysis) were carried out to investigate about the changes in the material induced by irradiation. Experimental results suggested that structural changes (double bonds, crosslinks, and oxidized species formation) occur in the polymer depending on the environmental conditions of the irradiation. Mechanical behavior is related to the structural modifications. A temperature of 110 degrees C before, during, and after the in vacuum irradiation of UHMWPE produces a high amount of crosslinks and improves polymeric tensile and wear resistance, compared to that of the untreated material.

  19. Electron beam inactivation of Tulane virus on fresh produce, and mechanism of inactivation of human norovirus surrogates by electron beam irradiation.

    PubMed

    Predmore, Ashley; Sanglay, Gabriel C; DiCaprio, Erin; Li, Jianrong; Uribe, R M; Lee, Ken

    2015-04-02

    Ionizing radiation, whether by electron beams or gamma rays, is a non-thermal processing technique used to improve the microbial safety and shelf-life of many different food products. This technology is highly effective against bacterial pathogens, but data on its effect against foodborne viruses is limited. A mechanism of viral inactivation has been proposed with gamma irradiation, but no published study discloses a mechanism for electron beam (e-beam). This study had three distinct goals: 1) evaluate the sensitivity of a human norovirus surrogate, Tulane virus (TV), to e-beam irradiation in foods, 2) compare the difference in sensitivity of TV and murine norovirus (MNV-1) to e-beam irradiation, and 3) determine the mechanism of inactivation of these two viruses by e-beam irradiation. TV was reduced from 7 log10 units to undetectable levels at target doses of 16 kGy or higher in two food matrices (strawberries and lettuce). MNV-1 was more resistant to e-beam treatment than TV. At target doses of 4 kGy, e-beam provided a 1.6 and 1.2 log reduction of MNV-1 in phosphate buffered saline (PBS) and Dulbecco's Modified Eagle Medium (DMEM), compared to a 1.5 and 1.8 log reduction of TV in PBS and Opti-MEM, respectively. Transmission electron microscopy revealed that increased e-beam doses negatively affected the structure of both viruses. Analysis of viral proteins by SDS-PAGE found that irradiation also degraded viral proteins. Using RT-PCR, irradiation was shown to degrade viral genomic RNA. This suggests that the mechanism of inactivation of e-beam was likely the same as gamma irradiation as the damage to viral constituents led to inactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Emission from Polymethyl Methacrylate Irradiated by a Beam of Runaway Electrons of Subnanosecond Pulse Durations

    NASA Astrophysics Data System (ADS)

    Baksht, E. Kh.; Burachenko, A. G.; Beloplotov, D. V.; Tarasenko, V. F.

    2016-08-01

    Spectral and amplitude-temporal characteristics of emission from polymethyl methacrylate (fiberglass, PMMA) irradiated with a beam of runaway electrons of subnanosecond duration are investigated. It is found that at the beam current pulse duration within 200-600 ps at half maximum and the beam current density 10-200 A/cm2, the intensity maximum is registered at the wavelength ~490 nm and the emission pulse FWHM in the visible spectrum is ~1.5 ns at the half width. It is shown that the main contribution into the emission comes from luminescence.

  1. Tuning the transport gap of functionalized graphene via electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Martins, Steven E.; Withers, Freddie; Dubois, Marc; Craciun, Monica F.; Russo, Saverio

    2013-03-01

    We demonstrate a novel method to tune the energy gap ɛ1 between the localized states and the mobility edge of the valence band in chemically functionalized graphene by changing the coverage of fluorine adatoms via electron-beam irradiation. From the temperature dependence of the electrical transport properties we show that ɛ1 in partially fluorinated graphene CF0.28 decreases upon electron irradiation up to a dose of 0.08 C cm-2. For low irradiation doses (<0.1 C cm-2) partially fluorinated graphene behaves as a lightly doped semiconductor with impurity bands close to the conduction and valence band edges, whereas for high irradiation doses (>0.2 C cm-2) the electrical conduction takes place via Mott variable range hopping.

  2. Influence of electron beam irradiation on mechanical and thermal properties of polypropylene/polyamide blend

    SciTech Connect

    Nakamura, Shigeya; Tokumitsu, Katsuhisa

    2014-05-15

    The effects of electron beam irradiation on the mechanical and thermal properties of polypropylene (PP) and polyamide6 (PA6) blends-with talc 20 wt% as filler, SEBS-g-MAH as compatibilizer, and triallyl isocyanurate as crosslinking agent-were investigated. Although the tensile and flexural moduli and strengths of the PP/PA6 blends with talc, SEBS-g-MAH, and TAIC could be increased by the application of electron beam irradiation, the impact strength was decreased. Ddifferential scanning calorimetryer measurements showed that the melting temperatures of all PP/PA6 blends were decreased with increases in the electron beam irradiationdose. From dynamic mechanical analyzer results, a storage modulus curve in the plateau region was observed only in the PP/PA6 blends with talc, SEBS-g-MAH, and TAIC; the storage modulus increased with increasing electron beam irradiation dose, indicating that the three-dimensional network developed gradually in the more amorphous PA6. As a result, the most significant improvement observed in heat distortion tests under high load (1.8 MPa) occurred at 200 kGy.

  3. Direct nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation.

    PubMed

    El Mel, Abdel-Aziz; Stephant, Nicolas; Gautier, Romain

    2016-10-06

    In this communication, we report on the growth, direct writing and nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation using a scanning electron microscope. The nanoblocks are produced by placing a droplet of an ethylene glycol solution containing silver nitrate and polyvinylpyrrolidone diluted in ethanol directly on a hot substrate heated up to 150 °C. Upon complete evaporation of the droplet, nanospheres, nano- and micro-triangles and nanoblocks made of silver-containing polymers, form over the substrate surface. Considering the nanoblocks as a model system, we demonstrate that such nanostructures are extremely sensitive to the e-beam extracted from the source of a scanning electron microscope operating at low acceleration voltages (between 5 and 7 kV). This sensitivity allows us to efficiently create various nanopatterns (e.g. arrays of holes, oblique slits and nanotrenches) in the material under e-beam irradiation. In addition to the possibility of writing, the nanoblocks revealed a self-healing ability allowing them to recover a relatively smooth surface after etching. Thanks to these properties, such nanomaterials can be used as a support for data writing and erasing on the nanoscale under low energy electron beam irradiation.

  4. Development of a novel device for applying uniform doses of electron beam irradiation on carcasses.

    PubMed

    Maxim, Joseph E; Neal, Jack A; Castillo, Alejandro

    2014-01-01

    The Maxim's Electron Scatter Chamber (Maxim Chamber) was developed to obtain uniform dose distribution when applying electron beam (e-beam) irradiation to materials of irregular surface. This was achieved by placing a stainless steel mesh surrounding a cylindrical area where the target sample was placed. Upon contact with the mesh, electrons scatter and are directed onto the target from multiple angles, eliminating the e-beam linearity and resulting in a uniform dose distribution over the target surface. The effect of irradiation in the Maxim Chamber on dose distribution and pathogen reduction was tested on rabbit carcasses to simulate other larger carcasses. The dose uniformity ratio (DUR) on the rabbit carcasses was 1.8, indicating an acceptable dose distribution. On inoculated carcasses, this treatment reduced Escherichia coli O157:H7 by >5 log cycles. These results indicate that carcass irradiation using e-beam is feasible using the Maxim's electron scattering chamber. Appropriate adjustments will be further needed for commercial application on beef and other animal carcasses.

  5. Determination of the Displacement Energies of O, Si and Zr Under Electron Beam Irradiation

    SciTech Connect

    Edmondson, P. D.; Weber, William J.; Namavar, Fereydoon; Zhang, Yanwen

    2012-03-01

    The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to ~1.5 x 10²²e m² has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron–solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be ~400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

  6. Flexible cadmium telluride thin films grown on electron-beam-irradiated graphene/thin glass substrates

    SciTech Connect

    Seo, Won-Oh; Kim, Jihyun; Koo, Yong Hwan; Kim, Byungnam; Lee, Byung Cheol; Kim, Donghwan

    2014-08-25

    We demonstrate the close-spaced sublimation growth of polycrystalline cadmium telluride (CdTe) thin films on a flexible graphene electrode/thin glass substrate structure. Prior to the growth of CdTe films, chemical-vapor-deposited graphene was transferred onto a flexible glass substrate and subjected to electron-beam irradiation at an energy of 0.2 MeV in order to intentionally introduce the defects into it in a controlled manner. Micro-Raman spectroscopy and sheet resistance measurements were employed to monitor the damage and disorder in the electron-beam irradiated graphene layers. The morphology and optical properties of the CdTe thin films deposited on a graphene/flexible glass substrate were systematically characterized. The integration of the defective graphene layers with a flexible glass substrate can be a useful platform to grow various thin-film structures for flexible electronic and optoelectronic devices.

  7. Time-dependent charge distributions in polymer films under electron beam irradiation

    SciTech Connect

    Yasuda, Masaaki; Kainuma, Yasuaki; Kawata, Hiroaki; Hirai, Yoshihiko; Tanaka, Yasuhiro; Watanabe, Rikio; Kotera, Masatoshi

    2008-12-15

    The time-dependent charge distribution in polymer film under electron beam irradiation is studied by both experiment and numerical simulation. In the experiment, the distribution is measured with the piezoinduced pressure wave propagation method. In the simulation, the initial charge distribution is obtained by the Monte Carlo method of electron scattering, and the charge drift in the specimen is simulated by taking into account the Poisson equation, the charge continuity equation, Ohm's law, and the radiation-induced conductivity. The results obtained show that the negative charge deposited in the polymer film, whose top and bottom surfaces are grounded, drifts toward both grounded electrodes and that twin peaks appear in the charge distribution. The radiation-induced conductivity plays an important role in determining the charge distribution in the polymer films under electron beam irradiation.

  8. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, Qingguo; Zhou, Xue; Zeng, Jinxia; Wang, Jizeng

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the sbnd Cdbnd O group at 1701 cm-1, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  9. Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

    NASA Astrophysics Data System (ADS)

    Bee, Soo-Tueen; Ratnam, C. T.; Sin, Lee Tin; Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang; Rahmat, A. R.

    2014-09-01

    The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20-80% LDPE and were exposed to electron beam irradiation dosages of 20-120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young's modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

  10. Spectroscopic analysis and mechanical properties of electron beam irradiated polypropylene/epoxidized natural rubber (PP/ENR) polymer blends

    NASA Astrophysics Data System (ADS)

    Senna, Magdy M. H.; Abdel-Fattah, Atef A.; Abdel-Monem, Y. K.

    2008-06-01

    Polymer blends based on different ratios of polypropylene (PP) and epoxidized natural rubber (ENR) were prepared by melt extrusion into sheets. The PP/ENR blends were exposed to various dose of accelerated electrons. The formation of free radicals during and after electron beam irradiation was illustrated by electron spin resonance (ESR). Also, the effect of electron beam irradiation on the mechanical and structural morphology was investigated by stress-strain behavior and scanning electron microscope (SEM). The ESR spectra indicated the formation of alkyl and allyl radicals during electron beam irradiation and peroxyl radicals during the post effect. The rate of radical decay was found to be second-order kinetics. The improvement in mechanical properties and structural morphology was confirmed to be due to the effect of electron beam irradiation.

  11. The effect of electron beam irradiation on silver-sodium ion exchange in silicate glasses

    NASA Astrophysics Data System (ADS)

    Sidorov, Alexander I.; Prosnikov, Mikhail A.

    2016-04-01

    It is shown experimentally that electron irradiation of sodium-silicate glasses makes possible the control of the subsequent ion exchange Ag+ ↔ Na+ process in a salt melt. The reason of this effect is the negatively charged regions formation in a glass volume during electron irradiation. The electric field, produced by these regions in glass volume, results in positive Na+ ions field migration into them. The spatial redistribution of Na+ ions results in the decrease of the ion exchange efficiency, or the ion exchange can be even blocked. This led to the decrease of the luminescence intensity of neutral silver molecular clusters in the irradiated zone, and effect on the silver nanoparticles formation during the subsequent thermal treatment. The observed effects can be used for the control of ion exchange processes during integrated optics devices fabrication, and for the electron-beam recording of optical information.

  12. Virus inactivation studies using ion beams, electron and gamma irradiation

    NASA Astrophysics Data System (ADS)

    Smolko, Eduardo E.; Lombardo, Jorge H.

    2005-07-01

    Known methods of virus inactivation are based on the chemical action of some substances such as acetylethylenimine, betapropiolactone, glycidalaldehyde, formaldehyde, etc. In such a process, the viral suspension should be kept at room or higher temperatures for 24-48 h. Under these conditions, physical and chemical agents act to degrade the virus antigenic proteins. On the contrary with ionizing radiations at low temperatures, the treatment does not cause such degradation allowing the study of different viral functions. In this work, particle (α, d and ß) and γ irradiations were used for partial and total inactivation of Foot and Mouth Disease Virus (FMDV), Rauscher Leukemia Virus (RLV) and Herpes Simplex Virus (HSV). Obtention of the D37 dose from survival curves and the application of the target theory, permitted the determination of molecular weight of the nucleic acid genomes, EBR values and useful information for vaccine preparation. For RLV virus, a two target model of the RNA genome was deduced in accordance with biological information while from data from the literature and our own work on the structure of the scrapie prion, considering the molecular weight obtained by application of the theory, a new model for prion replication is presented, based on a trimer molecule.

  13. Ionic liquids influence on the surface properties of electron beam irradiated wood

    NASA Astrophysics Data System (ADS)

    Croitoru, Catalin; Patachia, Silvia; Doroftei, Florica; Parparita, Elena; Vasile, Cornelia

    2014-09-01

    In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

  14. Buried amorphous layers by electronic excitation in ion-beam irradiated lithium niobate: Structure and kinetics

    SciTech Connect

    Olivares, J.; Garcia-Navarro, A.; Garcia, G.; Agullo-Lopez, F.; Agullo-Rueda, F.; Garcia-Cabanes, A.; Carrascosa, M.

    2007-02-01

    The formation of buried heavily damaged and amorphous layers by a variety of swift-ion irradiations (F at 22 MeV, O at 20 MeV, and Mg at 28 MeV) on congruent LiNbO{sub 3} has been investigated. These irradiations assure that the electronic stopping power S{sub e}(z) is dominant over the nuclear stopping S{sub n}(z) and reaches a maximum value inside the crystal. The structural profile of the irradiated layers has been characterized in detail by a variety of spectroscopic techniques including dark-mode propagation, micro-Raman scattering, second-harmonic generation, and Rutherford backscattering spectroscopy/channeling. The growth of the damage on increasing irradiation fluence presents two differentiated stages with an abrupt structural transition between them. The heavily damaged layer reached as a final stage is optically isotropic (refractive index n=2.10, independent of bombarding ion) and has an amorphous structure. Moreover, it has sharp profiles and its thickness progressively increases with irradiation fluence. The dynamics under irradiation of the amorphous-crystalline boundaries has been associated with a reduction of the effective amorphization threshold due to the defects created by prior irradiation (cumulative damage). The kinetics of the two boundaries of the buried layer is quite different, suggesting that other mechanisms aside from the electronic stopping power should play a role on ion-beam damage.

  15. Effects of electron beam irradiation (EBI) on structure characteristics and thermal properties of walnut protein flour.

    PubMed

    Zhao, Yue; Sun, Na; Li, Yong; Cheng, Sheng; Jiang, Chengyao; Lin, Songyi

    2017-10-01

    The effects of electron beam irradiation (EBI) on structure characteristics and thermal properties of walnut protein flour (WPF) were evaluated. The WPF was irradiated by 0-15.0kGy of the EBI. Scanning electron microscopy and X-ray diffraction analysis revealed that the EBI irradiation could not change the amorphous structure of WPF but resulted in puncture pores and fragmentation on microcosmic surface of WPF. Besides, low-field nuclear magnetic resonance results showed the EBI irradiation had effects on increasing denaturation temperature of WPF to 70°C, and the particle size of WPF hydrolysates (WPFHs) irradiated by EBI at dose of 5.0kGy significantly (P<0.05) increased to 753.8±21.0nm. The molecular weight of WPFHs at dose of 5.0kGy increased compared with that of non-irradiated sample. These revealed that EBI irradiation led to aggregation or cross-linking of the walnut protein. In addition, thermogravimetric analysis and zeta potential values indicated that the EBI enhanced thermal stability of WPF and didn't affect the physical stability of the WPFHs. Therefore, these results provided a theoretical foundation that the EBI applies on improving the properties of protein in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Improving enzymatic hydrolysis of industrial hemp ( Cannabis sativa L.) by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Shin, Soo-Jeong; Sung, Yong Joo

    2008-09-01

    The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

  17. Dynamic rheology behavior of electron beam-irradiated cellulose pulp/NMMO solution

    NASA Astrophysics Data System (ADS)

    Zhou, Ruimin; Deng, Bangjun; Hao, Xufeng; Zhou, Fei; Wu, Xinfeng; Chen, Yongkang

    2008-08-01

    The rheological behavior of irradiated cellulose pulp solution by electron beam was investigated. Storage modulus G', loss modulus G″, the dependence of complex viscosity η* and frequency ω of cellulose solutions were measured by DSR-200 Rheometer (Rheometrics co., USA). The molecular weight of irradiated cellulose was measured via the intrinsic viscosity measurement using an Ubbelohde capillary viscometer. The crystalline structure was studied by FTIR Spectroscopy. The results congruously showed that the molecular weight of pulp cellulose decrease and the molecular weight distribution of cellulose become narrow with increase in the irradiation dose. Moreover, the crystalline structure of the cellulose was destroyed, the force of the snarl between the cellulose molecules weakens and the accessibility of pulp spinning is improved. The study supplies some useful data for spinnability of irradiated cellulose and technical data to the filature industry.

  18. Effects of gamma and electron beam irradiation on the microbial quality of steamed tofu rolls

    NASA Astrophysics Data System (ADS)

    Jia, Qian; Gao, Meixu; Li, Shurong; Wang, Zhidong

    2013-01-01

    The effectiveness of two kinds of radiation processing, gamma and electron beam (ebeam) irradiation, for the inactivation of Staphylococcus aureus, Salmonella enteritidis and Listeria innocua which were inoculated in pre-sterilised steamed tofu rolls was studied. The corresponding effects of both irradiation types on total bacterial counts (TBCs) in commercial steamed tofu rolls available in the market were also examined. The microbiological results demonstrated that gamma irradiation yielded D10 values of 0.20, 0.24 and 0.22 kGy for S. aureus, S. enteritidis and L. innocua, respectively. The respective D10 values for ebeam irradiation were 0.31, 0.35 and 0.27 kGy. Gamma and ebeam irradiation yielded D10 values of 0.48 and 0.43 kGy for total bacterial counts in commercial steamed tofu rolls, respectively. The results suggest that ebeam irradiation has similar effect on decreasing TBCs in steamed tofu rolls, and gamma irradiation is slightly more effective than ebeam irradiation in reducing the populations of pathogenic bacteria. The observed differences in D10-values between them might be due to the significant differences in dose rate applied, and radiation processing of soybean products to improve their microbial quality could be available for other sources of protein.

  19. Evaluation of fatigue crack behavior in electron beam irradiated polyethylene pipes

    NASA Astrophysics Data System (ADS)

    Pokharel, Pashupati; Jian, Wei; Choi, Sunwoong

    2016-09-01

    A cracked round bar (CRB) fatigue test was employed to determine the slow crack growth (SCG) behavior of samples from high density polyethylene (HDPE) pipes using PE4710 resin. The structure property relationships of fatigue failure of polyethylene CRB specimens which have undergone various degree of electron beam (EB) irradiation were investigated by observing fatigue failure strength and the corresponding fracture surface morphology. Tensile test of these HDPE specimens showed improvements in modulus and yield strength while the failure strain decreased with increasing EB irradiation. The CRB fatigue test of HDPE pipe showed remarkable effect of EB irradiation on number of cycles to failure. The slopes of the stress-cycles to failure curve were similar for 0-100 kGy; however, significantly higher slope was observed for 500 kGy EB irradiated pipe. Also, the cycle to fatigue failure was seen to decrease as with EB irradiation in the high stress range, ∆σ=(16 MPa to 10.8 MPa); however, 500 kGy EB irradiated samples showed longer cycles to failure than the un-irradiated specimens at the stress range below 9.9 MPa and the corresponding initial stress intensity factor (∆KI,0)=0.712 MPa m1/2. The fracture surface morphology indicated that the cross-linked network in 500 kGy EB irradiated PE pipe can endure low dynamic load more effectively than the parent pipe.

  20. Movement of basal plane dislocations in GaN during electron beam irradiation

    SciTech Connect

    Yakimov, E. B.; Vergeles, P. S.; Polyakov, A. Y.; Lee, In-Hwan; Pearton, S. J.

    2015-03-30

    The movement of basal plane segments of dislocations in low-dislocation-density GaN films grown by epitaxial lateral overgrowth as a result of irradiation with the probing beam of a scanning electron microscope was detected by means of electron beam induced current. Only a small fraction of the basal plane dislocations was susceptible to such changes and the movement was limited to relatively short distances. The effect is explained by the radiation enhanced dislocation glide for dislocations pinned by two different types of pinning sites: a low-activation-energy site and a high-activation-energy site. Only dislocation segments pinned by the former sites can be moved by irradiation and only until they meet the latter pinning sites.

  1. Use of electron beam irradiation to improve the microbiological safety of Hippophae rhamnoides

    NASA Astrophysics Data System (ADS)

    Minea, R.; Nemţanu, M. R.; Manea, S.; Mazilu, E.

    2007-09-01

    Sea buckthorn ( Hippophae rhamnoides) is increasingly used in food supplements due to its dietary and medicinal compounds with a beneficial role in human diet and health. As many other medicinal plants, sea buckthorn can be contaminated with microorganisms which exerts an important impact on the overall quality of the products. Irradiation is an effective method for food preservation because it is able to destroy pathogenic microorganisms keeping the organoleptic and nutritional characteristics of the foods. The objective of the present study was to investigate the application of electron beam irradiation in order to improve the microbiological safety of sea buckthorn. The experimental results indicated that the electron beam treatment might be a good method to remove undesirable microorganisms from sea buckthorn without significant changes in its active principles.

  2. New green polymeric composites based on hemp and natural rubber processed by electron beam irradiation.

    PubMed

    Stelescu, Maria-Daniela; Manaila, Elena; Craciun, Gabriela; Dumitrascu, Maria

    2014-01-01

    A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica). The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

  3. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    PubMed Central

    Stelescu, Maria-Daniela; Craciun, Gabriela; Dumitrascu, Maria

    2014-01-01

    A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica). The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics. PMID:24688419

  4. Local Coulomb explosion of boron nitride nanotubes under electron beam irradiation.

    PubMed

    Wei, Xianlong; Tang, Dai-Ming; Chen, Qing; Bando, Yoshio; Golberg, Dmitri

    2013-04-23

    In many previous reports, the engineering of nanostructures using electron beam irradiation (EBI) in a high vacuum has primarily been based on the knock-on atom displacement. Herein, we report a new phenomenon under EBI that can also be effectively used to engineer a nanostructure: local Coulomb explosion (LCE) of cantilevered multiwalled boron nitride nanotubes (BNNTs) resulted from their profound positive charging. The nanotubes are gradually shortened, while the tubular shells at free ends are torn into graphene-like pieces and then removed during LCE. The phenomenon is dependent not only on the characteristics of an incident electron beam, as in the case of a common knock-on process, but also on the cantilevered tube length. Only after the electron beam density and tube length exceed the threshold values can LCE take place, and the threshold value for one of the parameters decreases with increasing the value of the other one. A model based on the diffusion of electron-irradiation-induced holes along a BNNT is proposed to describe the positive charge accumulation and can well explain the observed LCE. LCE opens up an efficient and versatile way to engineer BNNTs and other dielectric nanostructures with a shorter time and a lower beam density than those required for the knock-on effect-based engineering.

  5. Effect of low dose electron beam irradiation on the alteration layer formed during nuclear glass leaching

    NASA Astrophysics Data System (ADS)

    Mougnaud, S.; Tribet, M.; Renault, J.-P.; Jollivet, P.; Panczer, G.; Charpentier, T.; Jégou, C.

    2016-12-01

    This investigation concerns borosilicate glass leaching mechanisms and the evolution of alteration layer under electron beam irradiation. A simple glass doped with rare earth elements was selected in order to access mechanistic and structural information and better evaluate the effects of irradiation. It was fully leached in initially pure water at 90 °C and at high glass surface area to solution volume ratio (S/V = 20 000 m-1) in static conditions. Under these conditions, the system quickly reaches the residual alteration rate regime. A small particle size fraction (2-5 μm) was sampled in order to obtain a fairly homogeneous altered material enabling the use of bulk characterization methods. External irradiations with 10 MeV electrons up to a dose of 10 MGy were performed either before or after leaching, to investigate respectively the effect of initial glass irradiation on its alteration behavior and the irradiation stability of the alteration layer. Glass dissolution rate was analyzed by regular leachate samplings and the alteration layer structure was characterized by Raman, luminescence (continuous or time-resolved), and 29Si MAS NMR and EPR spectroscopy. It was shown that the small initial glass evolutions under irradiation did not induce any modification of the leaching kinetic nor of the structure of the alteration layer. The alteration process seemed to "smooth over" the created defects. Otherwise, the alteration layer and initial glass appeared to have different behaviors under irradiation. No Eu3+ reduction was detected in the alteration layer after irradiation and the defect creation efficiency was much lower than for initial glass. This can possibly be explained by the protective role of pore water contained in the altered material (∼20%). Moreover, a slight depolymerization of the silicon network of the altered glass under irradiation with electrons was evidenced, whereas in the initial glass it typically repolymerizes.

  6. Sustained transdermal release of diltiazem hydrochloride through electron beam irradiated different PVA hydrogel membranes

    NASA Astrophysics Data System (ADS)

    Bhunia, Tridib; Goswami, Luna; Chattopadhyay, Dipankar; Bandyopadhyay, Abhijit

    2011-08-01

    Extremely fast release of diltiazem hydrochloride (water soluble, anti anginal drug used to treat chest pain) together with its faster erosion has been the primary problem in conventional oral therapy. It has been addressed in this paper by encapsulating the drug in electron beam irradiated various poly (vinyl alcohol) hydrogel membranes and delivering it through transdermal route. Results show excellent control over the release of diltiazem hydrochloride through these membranes subject to their physico-mechanicals.

  7. Transitory and permanent effects of electron beam irradiation on insulating materials

    NASA Astrophysics Data System (ADS)

    Oproiu, C.; Martin, D.; Toma, M.; Marghitu, S.; Jianu, A.

    2000-05-01

    Transitory and permanent effects of electron beam irradiation on mechanical and electrical properties of a large list of organic insulating materials, such as: polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), terephtalated polyethylene (PET), stratified phenol-paper (SPP), methylsthyrene butadiene rubber (MeStB), silicon rubber (SR), polyester resin (UPR) are presented. The principal mechanical and electrical properties analyzed were: tensile strength, elongation at break, sharing strength, dielectric strength, electrical resistivity, dielectric constant, dissipation factor.

  8. Effect of electron beam irradiation on the properties of crosslinked rubbers

    NASA Astrophysics Data System (ADS)

    Banik, Indranil; Bhowmick, Anil K.

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature ( Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy.

  9. Microstructural, thermal and antibacterial properties of electron beam irradiated Bombyx mori silk fibroin films

    SciTech Connect

    Asha, S.; Sanjeev, Ganesh; Sangappa; Naik, Prashantha; Chandra, K. Sharat

    2014-04-24

    The Bombyx mori silk fibroin (SF) films were prepared by solution casting method and the effects of electron beam on structural, thermal and antibacterial responses of the prepared films were studied. The electron irradiation for different doses was carried out using 8 MeV Microtron facility at Mangalore University. The changes in microstructural parameters and thermal stability of the films were investigated using Wide Angle X-ray Scattering (WAXS) and thermogravimetric analysis (TGA) respectively. Both microstructuralline parameters (crystallite size and lattice strain (g in %)) and thermal stability of the irradiated films have increased with radiation dosage. Agar diffusion method demonstrated the antibacterial activity of SF film which was increased after irradiation on both Gram-positive and Gram-negative species.

  10. Electron beam irradiation after reconstruction with silicone gel implant in breast cancer

    SciTech Connect

    Krishnan, L.; Krishnan, E.C.

    1986-06-01

    Irradiation for breast cancer in the presence of a silicone gel breast prosthesis is sometimes necessary. There is a concern among radiation and other oncologists as to whether the presence of the prosthetic implant would interfere with delivery of the needed irradiation doses. Electron beams, with their finite penetration and rapid fall-off, offer a mode of adequately treating the recurrence and minimizing the radiation to the underlying normal structures, such as the lung and the heart. The dose distribution using 9-20 MeV electrons in the presence of a breast prosthesis is compared to the dose distribution without the implant in a tissue equivalent water phantom. The results reveal no significant difference in the dose delivered due to the presence of the prosthesis. Clinical verification of the dosimetry in the presence of the prosthesis confirmed that the presence of the silicone gel implant does not compromise treatment by irradiation in the management of breast cancer.

  11. Electron beam irradiation in natural fibres reinforced polymers (NFRP)

    NASA Astrophysics Data System (ADS)

    Kechaou, B.; Salvia, M.; Fakhfakh, Z.; Juvé, D.; Boufi, S.; Kallel, A.; Tréheux, D.

    2008-11-01

    This study focuses on the electric charge motion in unsatured polyester and epoxy composites reinforced by natural fibres of Alfa type, treated by different coupling agents. The electric charging phenomenon is studied by scanning electron microscopy mirror effect (SEMME) coupled with the induced current method (ICM). Previously, using the same approach, glass fibre reinforced epoxy (GFRE) was studied to correlate mechanical [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Composites Science and Technology 64 (2004) 1467], or tribological [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Dielectric and friction behaviour of unidirectionalglass fibre reinforced epoxy (GFRE), Wear, 265 (2008) 763.] properties and dielectric properties. It was shown that the dielectric properties of the fibre-matrix interfaces play a significant role in the optimization of the composite. This result seems to be the same for natural fibre composites: the fibre-matrix interfaces allow a diffusion of the electric charges which can delocalize the polarization energy and consequently delay the damage of the composite. However, a non-suited sizing can lead to a new trapping of electric charges along these same interfaces with, as a consequence, a localization of the polarisation energy. The optimum composite is obtained for one sizing which helps, at the same time, to have a strong fibre-matrix adhesion and an easy flow of the electric charges along the interface.

  12. Properties and structure of vapor-deposited polyimide upon electron-beam irradiation

    SciTech Connect

    Tsai, F.-Y.; Kuo, Y.-H.; Harding, D.R.

    2006-03-15

    Vapor-deposited polyimide capsules from pyromellitic dianhydride and 4,4{sup '}-oxydianiline were irradiated with an electron beam that mimicked the {beta}-radiation emitted by tritium, a fuel that the capsules are to contain during the inertial confinement fusion process. The mechanical properties and gas permeability of the irradiated capsules were measured to examine their radiation resistance. Upon electron-beam irradiation at an energy of 8 keV and a dose of 120 MGy, the capsules showed 15% and 56% decrease in tensile strength and elongation at break, respectively, without significant change in gas permeability and Young's modulus. Analyses using x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy indicated that the chain cleavage and carbonization occurred but were confined in a thin layer at the top surface of the capsules. The shallow penetration of the low-energy electron beam used, as well as the existence of cross-linking in the vapor-deposited polyimide, may have led to the smaller magnitude of property degradation in the capsules compared to that reported for solution-cast polyimide.

  13. Synthesis and characterisation of starch grafted superabsorbent via 10 MeV electron-beam irradiation.

    PubMed

    Zhang, Sufen; Wang, Wei; Wang, Haiyan; Qi, Wenyuan; Yue, Ling; Ye, Qingfu

    2014-01-30

    A starch-graft-polyacrylamide (St-g-PAM) superabsorbent crosslinked by N,N'-methyl bisacrylamide (MBA) was prepared using 10 MeV simultaneous electron beam irradiation at room temperature and subsequent alkaline hydrolysis. The effects of the irradiation dose, acryliamide-to-anhydroglucose unit (AM-to-AGU) ratio and crosslinker amount on the properties of the obtained polymers were evaluated. The structure of the graft copolymer was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Optimisation treatments were carried out and found for a total dose of 8 kGy, an AM-to-AGU ratio of 4.5 mol mol(-1) and a crosslinker-to-AM ratio of 0.4%mol mol(-1). The obtained superabsorbent polymer showed the maximum absorptions of 1,452 gg(-1) and 83 gg(-1) for distilled water and saline solution, respectively (relative to its own dry weight). The results suggest 10 MeV electron beam irradiation is more efficient than γ-ray irradiation due to its higher energy and dose rate.

  14. Efficacy of Traditional Almond Decontamination Treatments and Electron Beam Irradiation against Heat-Resistant Salmonella Strains.

    PubMed

    Cuervo, Mary P; Lucia, Lisa M; Castillo, Alejandro

    2016-03-01

    Two outbreaks of salmonellosis were linked to the consumption of raw almonds from California in 2001 and 2004. As a result, federal regulations were developed, which mandate that all almonds grown in California must be treated with a process that results in a 4-log reduction of Salmonella. Because most of the technologies approved to treat almonds rely on the application of heat to control Salmonella, an evaluation of alternative technologies for inactivating heat-resistant Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W was needed. In this study, almonds were inoculated with Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W and then treated with an electron beam (e-beam) or by blanching or oil roasting. The irradiation D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W treated with e-beam were 0.90 and 0.72 kGy, respectively. For heat treatments, thermal D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W strains were 15.6 and 12.4 s, respectively, when subjected to blanching at 88°C and 13.2 and 10.9 s, respectively, when roasted in oil at 127 ± 2°C. No significant differences in irradiation and thermal treatment results were observed between Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W (P > 0.05), indicating that e-beam irradiation may be a feasible technology for reducing Salmonella in almonds. However, the sensory changes resulting from irradiating at the doses used in this study must be evaluated before e-beam irradiation can be used as a nonthermal alternative for decontamination of almonds.

  15. Post-synthesis carbon doping of individual multiwalled boron nitride nanotubes via electron-beam irradiation.

    PubMed

    Wei, Xianlong; Wang, Ming-Sheng; Bando, Yoshio; Golberg, Dmitri

    2010-10-06

    We report on post-synthesis carbon doping of individual boron nitride nanotubes (BNNTs) via in situ electron-beam irradiation inside an energy-filtering 300 keV high-resolution transmission electron microscope. The substitution of C for B and N atoms in the honeycomb lattice was demonstrated through electron energy loss spectroscopy, spatially resolved energy-filtered elemental mapping, and in situ electrical measurements. Substitutional C doping transformed BNNTs from electrical insulators to conductors. In comparison with the existing post-synthesis doping methods for nanoscale materials (e.g., ion implantation and diffusion), the discovered electron-beam-induced doping is a well-controlled, little-damaging, room-temperature, and simple strategy that is expected to demonstrate great promise for post-synthesis doping of diverse nanomaterials in the future.

  16. Energy deposition through radiative processes in absorbers irradiated by electron beams

    NASA Astrophysics Data System (ADS)

    Tatsuo, Tabata; Pedro, Andreo; Kunihiko, Shinoda; Rinsuke, Ito

    1994-09-01

    The component of energy deposition due to radiative processes (bremsstrahlung component) in absorbers irradiated by electron beams has been computed together with the total energy deposition by using the ITS Monte Carlo system version 3.0. Plane-parallel electron beams with energies from 0.1 to 100 MeV have been assumed to be incident normally on the slab absorber, whose thickness is 2.5 times the continuous slowing-down approximation (csda) range of the incident electrons. Absorber materials considered are elemental solids with atomic numbers between 4 and 92 (Be, C, Al, Cu, Ag, Au and U). An analytic formula is given to express the depth profile of the bremsstrahlung component as a function of scaled depth (depth in units of the csda range), incident-electron energy and absorber atomic number. It is also applicable to compounds.

  17. Space charge modeling in electron-beam irradiated polyethylene: Fitting model and experiments

    SciTech Connect

    Le Roy, S.; Laurent, C.; Teyssedre, G.; Baudoin, F.; Griseri, V.

    2012-07-15

    A numerical model for describing charge accumulation in electron-beam irradiated low density polyethylene has been put forward recently. It encompasses the generation of positive and negative charges due to impinging electrons and their transport in the insulation. However, the model was not optimized to fit all the data available regarding space charge dynamics obtained using up-to-date pulsed electro-acoustic techniques. In the present approach, model outputs are compared with experimental space charge distribution obtained during irradiation and post-irradiation, the irradiated samples being in short circuit conditions or with the irradiated surface at a floating potential. A unique set of parameters have been used for all the simulations, and it encompasses the transport parameters already optimized for charge transport in polyethylene under an external electric field. The model evolution in itself consists in describing the recombination between positive and negative charges according to the Langevin formula, which is physically more accurate than the previous description and has the advantage of reducing the number of adjustable parameters of the model. This also provides a better description of the experimental behavior underlining the importance of recombination processes in irradiated materials.

  18. Space charge modeling in electron-beam irradiated polyethylene: Fitting model and experiments

    NASA Astrophysics Data System (ADS)

    Le Roy, S.; Baudoin, F.; Griseri, V.; Laurent, C.; Teyssèdre, G.

    2012-07-01

    A numerical model for describing charge accumulation in electron-beam irradiated low density polyethylene has been put forward recently. It encompasses the generation of positive and negative charges due to impinging electrons and their transport in the insulation. However, the model was not optimized to fit all the data available regarding space charge dynamics obtained using up-to-date pulsed electro-acoustic techniques. In the present approach, model outputs are compared with experimental space charge distribution obtained during irradiation and post-irradiation, the irradiated samples being in short circuit conditions or with the irradiated surface at a floating potential. A unique set of parameters have been used for all the simulations, and it encompasses the transport parameters already optimized for charge transport in polyethylene under an external electric field. The model evolution in itself consists in describing the recombination between positive and negative charges according to the Langevin formula, which is physically more accurate than the previous description and has the advantage of reducing the number of adjustable parameters of the model. This also provides a better description of the experimental behavior underlining the importance of recombination processes in irradiated materials.

  19. A comparative study of the effect of gamma and electron beam irradiation on the optical and structural properties of polyurethane

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Abutalib, M. M.

    2011-03-01

    The effects of both gamma and electron beam irradiation on the color changes of polyurethane were investigated. Samples from polyurethane were classified into two groups. The first group was exposed to gamma doses at levels between 20 and 200 kGy. The second group was exposed to an electron beam with similar doses. The transmission of these samples in the wavelength range 370-780 nm, as well as any color changes, was studied. The Commission International de E'Claire (CIE units X, Y and Z) methodology is used in this work for the description of the colored samples. Additionally, the color differences between the non-irradiated sample and those irradiated with different gamma or electron beam doses were calculated. The results indicate that the polyurethane polymer acquires color changes under gamma or electron beam irradiation, but the response of polyurethane to color changes by electron beam irradiation is higher than the response to gamma irradiation. The structural modifications in the gamma and electron beam-irradiated polyurethane samples have also been studied as a function of the dose using the refractive index and Fourier transform infrared (FTIR) spectroscopy.

  20. Effect of electron beam irradiation on forensic evidence. 2. Analysis of writing inks on porous surfaces.

    PubMed

    Ramotowski, Robert S; Regen, Erin M

    2007-05-01

    The effect of electron beam irradiation on a series of different writing inks is described. As the anthrax-tainted letters were discovered in October 2001, the U.S. government began to experiment with the use of the electron beam irradiation process for destroying such biological agents. Plans initially considered a large-scale countrywide use of this technology. However, over time the scope of this plan as well as the radiation dosage were reduced, especially when some adverse consequences to mailed items subjected to this process were observed. Little data existed at the time to characterize what level of damage might be expected to occur with common items sent through the mail. This was especially important to museums and other institutions that routinely ship valuable and historic items through the mail. Although the Smithsonian Institution initiated some studies of the effect of electron beam irradiation on archived materials, little data existed on the effect that this process would have on forensic evidence. Approximately 97 different black, blue, red, green, and yellow writing inks were selected. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography (TLC) analysis were used to evaluate both the control and the irradiated samples. Some published studies reported changes in the presence/absence of dye bands in the chromatograms of irradiated writing inks. Some of these studies report the formation of additional dye bands on the chromatogram while others report missing dye bands. However, using standard testing guidelines and procedures, none of the 97 irradiated inks tested were found to show any significant optical or chemical differences from the control samples. In addition, random testing of some of the ink samples using a

  1. Influence of electron beam irradiation on growth of Phytophthora cinnamomi and its control in substrates

    NASA Astrophysics Data System (ADS)

    MigdaŁ, Wojciech; Orlikowski, Leszek B.; Ptaszek, Magdalena; Gryczka, Urszula

    2012-08-01

    Very extensive production procedure, especially in plants growing under covering, require methods, which would allow quick elimination or substantial reduction of populations of specific pathogens without affecting the growth and development of the cultivated plants. Among soil-borne pathogens, the Phytophthora species are especially dangerous for horticultural plants. In this study, irradiation with electron beam was applied to control Phytophthora cinnamomi. The influence of irradiation dose on the reduction of in vitro growth and the population density of the pathogen in treated peat and its mixture with composted pine bark (1:1), as well as the health of Chamaecyparis lawsoniana and Lavandula angustifolia plants were evaluated. Application of irradiation at a dose of 1.5 kGy completely inhibited the in vitro development of P. cinnamomi. This irradiation effect was connected with the disintegration of the hyphae and spores of the species. Irradiation of peat and its mixture with composted pine bark with 10 kGy resulted in the inhibition of stem base rot development in Ch. lawsoniana. Symptoms of the disease were not observed when the substrates were treated with 15 kGy. In the case of L. angustifolia, stem root rot was not observed on cuttings transplanted to infected peat irradiated at a dose of 10 kGy. Irradiation of the horticultural substrates did not affect plant growth.

  2. Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

    PubMed Central

    Manaila, Elena; Stelescu, Maria Daniela; Craciun, Gabriela; Ighigeanu, Daniel

    2016-01-01

    The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose. PMID:28773626

  3. Influence of electron beam irradiation on structural and optical properties of α-Ag2WO4 nanoparticles.

    PubMed

    A, Sreedevi; K P, Priyanka; K K, Babitha; S, Ganesh; Varghese, T

    2016-09-01

    The influence of 8MeV electron beam irradiation on the structural and optical properties of silver tungstate (α-Ag2WO4) nanoparticles synthesized by chemical precipitation method was investigated. The dose dependent effect of electron irradiation was investigated by various characterization techniques such as, X-ray diffraction, scanning electron microscopy, UV-vis absorption spectroscopy, photoluminescence and Raman spectroscopy. Systematic studies confirm that electron beam irradiation induces non-stoichiometry, defects and particle size variation on α-Ag2WO4, which in turn results changes in optical band gap, photoluminescence spectra and Raman bands. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Effect of laser and/or electron beam irradiation on void swelling in SUS316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Yang, Subing; Yang, Zhanbing; Wang, Hui; Watanabe, Seiichi; Shibayama, Tamaki

    2017-05-01

    Large amounts of void swelling still limit the application of austenitic stainless steels in nuclear reactors due to radiation-induced lattice point defects. In this study, laser and/or beam irradiation was conducted in a temperature range of 573-773 K to explore the suppression of void swelling. The results show that during sequential laser-electron beam irradiation, the void nucleation is enhanced because of the vacancy clusters and void nuclei formed under pre-laser irradiation, causing greater void swelling than single electron beam irradiation. However, simultaneous laser-electron dual-beam irradiation exhibits an obvious suppression effect on void swelling due to the enhanced recombination between interstitials and vacancies in the temperature range of 573-773 K; especially at 723 K, the swelling under simultaneous dual-beam irradiation is 0.031% which is only 22% of the swelling under electron beam irradiation (0.137%). These results provide new insight into the suppression of void swelling during irradiation.

  5. Control of natural microorganisms in chamomile (Chamomilla recutita L.) by gamma ray and electron beam irradiation.

    PubMed

    Al-Bachir, Mahfouz

    2017-01-01

    Microbial contamination levels and corresponding sensitivities to gamma rays (GR) and elec- tron beam (EB) irradiation were tested in chamomile (Chamomile recutta L.). Chamomile powders were treated with 10 and 20 kGy by GR and EB, respectively. Microbiological and chemical analyses were performed on controls and treated samples immediately after irradiation, and after 12 months of storage. The control samples of chamomile exhibited rather high microbiological contamination, exceeding the levels of 4 log10 CFU g-1   (CFU - colony forming units) reported by national and international authorities as the maximum permissible total count level. Irradiation with GR and EB was found to cause a reduction in microbial contamination proportionate to the dose delivered. The sterilizing effect of EB on microorganisms was higher than the GR one. A dose of 10 kGy of GR and EB significantly (p < 0.05) reduced the total bacte- rial, total coliform and total fungal contamination. A dose of 20 kGy of GR significantly (p < 0.05) reduced the total bacterial and total fungal contamination, while a 20 kGy dose of EB reduced the initial bacterial, total coliform and total fungal contamination to below detection level when the analysis was carried out im- mediately after irradiation treatment or after 12 months of storage. The comparative study demonstrated that electron beam was more effective for decontamination of chamomile powder than gamma irradiation.

  6. Comparative study on the effect of electron beam irradiation on the physical properties of ethylene-vinyl acetate copolymer composites

    NASA Astrophysics Data System (ADS)

    Wang, Bibo; Hong, Ningning; Shi, Yongqian; Wang, Biao; Sheng, Haibo; Song, Lei; Tang, Qinbo; Hu, Yuan

    2014-04-01

    Ethylene-vinyl acetate copolymer (EVA) flame retarded by a combination of cellulose acetate butyrate (CAB) microencapsulated ammonium polyphosphate (MCAPP) and polyamide-6 (PA-6) have been crosslinked by high energy electron beam irradiation. The effect of high energy electron beam irradiation on the crosslinking degree, mechanical, electrical and thermal properties of EVA/MCAPP/PA-6 cable material was studied by gel content, heat extention test, mechanical test, dynamic mechanical analysis, high-insulation resistance meter and thermogravimetric analysis. The gel content and heat extention test results showed that the EVA/MCAPP/PA-6 composites can be easily crosslinked by electron beam irradiation. The tensile strength of EVA composites was drastically increased from 16.2 to maximum 26.2 MPa as the electron beam irradiation dose increases from 0 to 160 kGy. The volatilized products of EVA/MCAPP/PA-6 composites were analyzed and compared by thermogravimetric analysis/infrared spectrometry (TG-FTIR).

  7. Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Kim, Junheon; Chung, Soon-Oh; Jang, Sin Ae; Jang, Miyeon; Park, Chung Gyoo

    2015-07-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24-48 h old), the larval (4-5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F1 egg hatching was completely inhibited at the dose of 350 Gy. ED99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge.

  8. Performance of electron beam irradiation for treatment of groundwater contaminated with acetone.

    PubMed

    Yoon, Y J; Jung, Y J; Han, B S; Kang, J W

    2009-01-01

    The purposes of this study were to evaluate the efficiency of acetone removal by electron beam irradiation in groundwater and the effect of various conditions. According to the results, the removal kinetics of acetone were pseudo first-order, and the removal efficiencies were expressed to the (%) removal and G-values. By adding sulfite, it was confirmed that acetone was mainly degraded by the reaction with the hydrated electrons. The presence of nitrate caused the removal of acetone to decrease. But there was no significant effect of alkalinity on the removal of acetone. The effect of the initial pH values (pH 5 to 9) on the acetone removal efficiency was negligible, but the pH value decreases due to the formation of acidic compounds after irradiation. Consequently, the radiation-induced removal reactions of acetone followed the pseudo-first-order kinetic model; in addition to the initial concentration of acetone, nitrate and the absorbed dose were important factors in removing acetone from an aqueous solution using electron beam irradiation. The effects of general pH and alkalinity on the degrading acetone were negligible.

  9. Inactivation effect of electron beam irradiation on fungal load of naturally contaminated maize seeds.

    PubMed

    Nemţanu, Monica R; Braşoveanu, Mirela; Karaca, Gürsel; Erper, İsmail

    2014-10-01

    This work focuses on the effect of accelerated electrons (0.1-6.2 kGy) on naturally attached fungi on maize seeds. The fungal viability and corresponding inactivation kinetics were determined. The inactivation and radiosensitivity of the most abundant species in the contaminant fungi detected on maize seeds (Aspergillus spp., Penicillium spp. and Fusarium spp.) are discussed. Fungal contamination of maize seeds decreased significantly with increasing irradiation dose. The survival curve of total fungi determined by the blotter test showed a sigmoidal pattern that can be attributed to the mixture of fungal subpopulations with different radiation sensitivities. This behaviour could be modelled well (R²  = 0.995) with a modified Gompertz equation. The predicted values for shoulder length and inactivation rate were 0.63 ± 0.10 kGy and 0.44 ± 0.04 kGy⁻¹ respectively. The sensitivity of the most common fungi to electron beam treatment followed the order Penicillium spp. > Fusarium spp. > Aspergillus spp., with total inactivation at irradiation doses of 1.7, 2.5 and 4.8 kGy respectively. The effect of electron beam treatment against fungi on naturally contaminated maize seeds depended on irradiation dose, allowing the control of maize fungal load. © 2014 Society of Chemical Industry.

  10. Effect of electron beam irradiation on thermal and mechanical properties of aluminum based epoxy composites

    NASA Astrophysics Data System (ADS)

    Visakh, P. M.; Nazarenko, O. B.; Sarath Chandran, C.; Melnikova, T. V.; Nazarenko, S. Yu.; Kim, J.-C.

    2017-07-01

    The epoxy resins are widely used in nuclear and aerospace industries. The certain properties of epoxy resins as well as the resistance to radiation can be improved by the incorporation of different fillers. This study examines the effect of electron beam irradiation on the thermal and mechanical properties of the epoxy composites filled with aluminum nanoparticles at percentage of 0.35 wt%. The epoxy composites were exposed to the irradiation doses of 30, 100 and 300 kGy using electron beam generated by the linear electron accelerator ELU-4. The effects of the doses on thermal and mechanical properties of the aluminum based epoxy composites were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The results revealed that the studied epoxy composites showed good radiation resistance. The thermal and mechanical properties of the aluminum based epoxy composites increased with increasing the irradiation dose up to 100 kGy and decreased with further increasing the dose.

  11. Characterization of nanocomposite film based on chitosan intercalated in clay platelets by electron beam irradiation.

    PubMed

    Shahbazi, Mahdiyar; Rajabzadeh, Ghadir; Ahmadi, Seyed Javad

    2017-02-10

    Different electron beam doses (10, 20, 30 and 40kGy) were tested with the purpose of investigating their influences on chitosan/clay (cloisite 20A) nanocomposite film to improve its functional performance by providing a crosslinked matrix. Water resistance, water contact angle and water barrier property of nanocomposite film were increased up to 30kGy, and then drastically decreased at the level of 40kGy. Characteristic diffraction peak of chitosan shifted to low angle with an increase in the interlayer spacing of the nanoclay after 30kGy irradiation, indicating a superlative intercalation. Crystallinity degree of chitosan/clay nanocomposite was increased in the amorphous region as the irradiation dose increased up to 30kGy. However, irradiation at level of 40kGy was converted the crystalline region of nanocomposite film to the amorphous state with losing the chitosan crystallinity. Irradiation increased the film tensile strength due to crosslinking of chitosan chains, with more pronounced effect at 30kGy and decreased it by chain degradation at 40kGy. A glass transition temperature was detected in DSC thermogram of chitosan/clay film, and it shifted to higher temperatures as the irradiation dose increased. Moreover, cold-crystallization exothermic peak of the chitosan/clay film moved to the lower temperature after irradiation, suggesting a faster crystallization rate. FE-SEM showed that the chitosan chains were more intercalated between the nanoclay platelets with increasing the irradiation dose. A progressive decrease in the roughness parameters of 20 and 30kGy irradiated nanocomposite films revealed by atomic force microscopy, whereas irradiation at 40kGy increased roughness values.

  12. Modification of PVC/ENR blend by electron beam irradiation: effect of crosslinking agents

    NASA Astrophysics Data System (ADS)

    Ratnam, C. T.; Zaman, K.

    1999-05-01

    In order to improve the mechanical properties of PVC/ENR blends, they were irradiated by using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. Changes in mechanical properties of the blends with increasing irradiation dose were investigated. In an attempt to maximize the beneficial effect of irradiation, the influence of multifunctional acrylates (MFA) such as TMPTA, HDDA and EHA on the 70/30 PVC/ENR blend was investigated. The properties studied include hardness, gel fraction, tensile strength, elongation at break and glass transition temperature. The results revealed that all mechanical properties increased with increasing irradiation dose with exception of elongation at break. The enhancement in blend properties was further improved by addition of MFA. This is attributed to the increase in crosslink density. The steady increase in gel fraction with irradiation dose and the shifting of the irradiation those towards a lower value to achieve 70% gel fraction upon addition of MFA has provided evidence for significant increase in crosslink density. Among the MFA employed in this studies, TMPTA was found to render highest mechanical properties to the blend with irradiation. Thus, TMPTA can be useful as an efficient crosslink enhancer to PVC/ENR blends. Results from Fourier transform infrared spectroscopy (FTIR) indicated radiation-induced crosslinks formed in PVC/ENR blends sensitized by TMPTA. The single glass transition temperature obtained confirms that the blend remains miscible upon irradiation with the presence of TMPTA. The changes in blend properties upon irradiation with the addition of acrylated polyurethene (PU) oligomer are also presented in this paper.

  13. Experimental electron beam irradiation of food and the induction of radioactivity.

    PubMed

    Findlay, D J; Parsons, T V; Sene, M R

    1992-05-01

    Samples of chicken, prawns, cheeses and spices were irradiated on the Harwell electron linear accelerator HELIOS at 20 MeV to assess mechanisms for the induction of radioactivity. The induced radioactivity was measured using a lead shielded Ge(Li) gamma-ray spectrometer, and the results were compared with activities calculated on the basis of photoneutron and photoproton reactions induced by real and virtual photons. In general, there was good agreement. Bounds were also placed on the induction of radioactivity by capture of neutrons produced in the food samples themselves. Further, the data were used to assess the effects of a gross malfunction of an electron beam irradiation facility; after 1 day, the specific activity of food samples irradiated to 10 kGy at 20 MeV was approximately 0.01 Bq g-1. In addition, food samples were also irradiated at 10 MeV, and irradiated and control samples were analysed for microbiological burden. Reductions in the microbiological burden of the food samples by factors consistent with those found in previous measurements were found.

  14. Thermoluminescence detection of Korean traditional foods exposed to Gamma and electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Kwon, J. H.; Chung, H. W.; Byun, M. W.; Kang, I. J.

    1998-06-01

    Thermoluminescence(TL) analysis was applied to detect irradiated Korean traditional condiments and soup mixes containing salt(NaCl). These food items, which are commercially irradiated in Korea, showed a consistently high correlation(R 2) between the absorbed doses and the corresponding TL responses. It was proved that table salt played a role as an in-built indicator in TL measurements and its concentration in test samples was proposed as a correction factor for varying conditions of TL measurements. Pre-established threshold values were successfully adopted to identify 167 coded samples of Ramen soup mixes, both non-irradiated and irradiated with gamma and electron-beam energy. The TL intensity of irradiated soup mixes decreased with the lapse of time, but was still distinguishable from that of the non-irradiated samples at the fourth month of ambient storage. Expected estimates of absorbed doses, 2.85 and 4.75 kGv were obtained using a quadratic equation with average values of 1.57 and 4.90 kGy, respectively.

  15. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.

    PubMed

    Bäcke, Olof; Lindqvist, Camilla; de Zerio Mendaza, Amaia Diaz; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R; Müller, Christian; Kristiansen, Per Magnus; Olsson, Eva

    2017-05-01

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.

    PubMed

    Bäcke, Olof; Lindqvist, Camilla; de Zerio Mendaza, Amaia Diaz; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R; Müller, Christian; Kristiansen, Per Magnus; Olsson, Eva

    2017-02-01

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Electron beam device

    DOEpatents

    Beckner, E.H.; Clauser, M.J.

    1975-08-12

    This patent pertains to an electron beam device in which a hollow target is symmetrically irradiated by a high energy, pulsed electron beam about its periphery and wherein the outer portion of the target has a thickness slightly greater than required to absorb the electron beam pulse energy. (auth)

  18. Tailoring the Performances of Lead Halide Perovskite Devices with Electron-Beam Irradiation.

    PubMed

    Yi, Ningbo; Wang, Shuai; Duan, Zonghui; Wang, Kaiyang; Song, Qinghai; Xiao, Shumin

    2017-09-01

    Lead halide perovskites are intensively studied in past few years due to their potential applications in optoelectronic devices such as solar cells, photodetectors, light-emitting diodes (LED), and lasers. In addition to the rapid developments in material synthesis and device fabrication, it is also very interesting to postsynthetically control the optical properties with external irradiations. Here, the influences of very low energy (10-20 keV) electron beam of standard electron beam lithography are experimentally explored on the properties of lead halide perovskites. It is confirmed that the radiolysis process also happens and it can selectively change the photoluminescence, enabling the direct formation of nanolaser array, microsized light emitter array, and micropictures with an electron beam writer. Interestingly, it is found that discontinuous metallic lead layers are formed on the top and bottom surfaces of perovskite microplate during the radiolysis process, which can act as carrier conducting layers and significantly increase the photocurrent of perovskite photodetector by a factor of 217%. By using the electron beam with low energy to modify the perovskite, this method promises to shape the emission patterns for micro-LED with well-preserved optical properties and improves the photocurrent of photodetector. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Effects of electron beam irradiation on the photoelectrochemical properties of TiO2 film for DSSCs

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Bin; Park, Dong-Won; Jeun, Joon-Pyo; Oh, Seung-Hwan; Nho, Young-Chang; Kang, Phil-Hyun

    2012-08-01

    iO2 has been widely utilized for various industrial applications such as photochemical cells, photocatalysts, and electrochromic devices. The crystallinity and morphology of TiO2 films play a significant role in determining the overall efficiency of dye-sensitized solar cells (DSSCs). In this study, the preparation of nanostructured TiO2 films by electron beam irradiation and their characterization were investigated for the application of DSSCs. TiO2 films were exposed to 20-100 kGy of electron beam irradiation using 1.14 MeV energy acceleration with a 7.46 mA beam current and 10 kGy/pass dose rates. These samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS) analysis. After irradiation, each TiO2 film was tested as a DSSC. At low doses of electron beam irradiation (20 kGy), the energy conversion efficiency of the film was approximately 4.0% under illumination of simulated sunlight with AM 1.5 G (100 mW/cm2). We found that electron beam irradiation resulted in surface modification of the TiO2 films, which could explain the observed increase in the conversion efficiency in irradiated versus non-irradiated films.

  20. Effects of Light and Electron Beam Irradiation on Halide Perovskites and Their Solar Cells.

    PubMed

    Klein-Kedem, Nir; Cahen, David; Hodes, Gary

    2016-02-16

    Hybrid alkylammonium lead halide perovskite solar cells have, in a very few years of research, exceeded a light-to-electricity conversion efficiency of 20%, not far behind crystalline silicon cells. These perovskites do not contain any rare element, the amount of toxic lead used is very small, and the cells can be made with a low energy input. They therefore already conform to two of the three requirements for viable, commercial solar cells-efficient and cheap. The potential deal-breaker is their long-term stability. While reasonable short-term (hours) and even medium term (months) stability has been demonstrated, there is concern whether they will be stable for the two decades or more expected from commercial cells in view of the intrinsically unstable nature of these materials. In particular, they have a tendency to be sensitive to various types of irradiation, including sunlight, under certain conditions. This Account focuses on the effect of irradiation on the hybrid (and to a small degree, all-inorganic) lead halide perovskites and their solar cells. It is split up into two main sections. First, we look at the effect of electron beams on the materials. This is important, since such beams are used for characterization of both the perovskites themselves and cells made from them (electron microscopy for morphological and compositional characterization; electron beam-induced current to study cell operation mechanism; cathodoluminescence for charge carrier recombination studies). Since the perovskites are sensitive to electron beam irradiation, it is important to minimize beam damage to draw valid conclusions from such measurements. The second section treats the effect of visible and solar UV irradiation on the perovskites and their cells. As we show, there are many such effects. However, those affecting the perovskite directly need not necessarily always be detrimental to the cells, while those affecting the solar cells, which are composed of several other phases

  1. Dependence of Mechanical and Thermal Properties of Thermoplastic Composites on Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Sok Won; Park, K.; Lee, S. H.; Kang, J. S.; Kang, K. H.

    2007-06-01

    Since the restrictions for environmental protection being strengthened, thermoplastics reinforced with natural fibers (NF’s), such as jute, kenaf, flax, etc. have appeared as alternatives to chemical plastics for automobile interior materials. In this study, the thermal conductivity, tensile strength, and deformation of several kinds of thermoplastic composites composed of 50% polypropylene (PP) and 50% natural fiber (NF) irradiated by an electron beam (energy: 0.5 MeV, dose: 0 20 kGy) were measured. The length and thickness of PP and NF are 80 ± 10 mm and 40 120 μm, respectively. The results show that the thermal conductivity and the tensile strength changed and became minimum, when the dose of the electron beam was 10 kGy. However, the effect of the dose on the deformation was not clear.

  2. Electron beam/γ-ray irradiation synthesis of gold nanoparticles and investigation of antioxidant activity

    NASA Astrophysics Data System (ADS)

    Duy Nguyen, Ngoc; Phu Dang, Van; Le, Anh Quoc; Hien Nguyen, Quoc

    2014-12-01

    Colloidal solutions of 1 mM gold nanoparticles (AuNPs) were synthesized by γ-ray Co-60 and electron beam irradiation using 1% water soluble chitosan (WSC) with different molecular weight (Mw) as stabilizer. The AuNPs size measured from TEM images was of 7.1 and 15.1 nm for electron beam and γ-ray Co-60, respectively. The AuNPs sizes of 9.8, 15.1 and 22.4 nm stabilized by different WSC Mw of 155 × 103, 78 × 103 and 29 × 103 g mol-1, respectively, were also synthesized by γ-ray Co-60 irradiation. Antioxidant activity of AuNPs with different size from 7.1 to 20.0 nm was investigated using free radical 2,2‧-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+). Results indicated that the smaller size of AuNPs exhibited higher antioxidant activity. In particular, the antioxidant efficiency was of nearly 100, 75, 65, 52 and 30% for 7.1, 9.8, 15.1, 20.0 nm AuNPs and WSC 0.1%, respectively, at the same reaction time of 270 min. Thus, due to the compatibility of WSC and the unique property of AuNPs, the pure colloidal AuNPs/WSC solutions synthesized by irradiation method can be potentially applied in biomedicine, cosmetics and in other fields as well.

  3. Tuning of Schottky barrier height of Al/n-Si by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Vali, Indudhar Panduranga; Shetty, Pramoda Kumara; Mahesha, M. G.; Petwal, V. C.; Dwivedi, Jishnu; Choudhary, R. J.

    2017-06-01

    The effect of electron beam irradiation (EBI) on Al/n-Si Schottky diode has been studied by I-V characterization at room temperature. The behavior of the metal-semiconductor (MS) interface is analyzed by means of variations in the MS contact parameters such as, Schottky barrier height (ΦB), ideality factor (n) and series resistance (Rs). These parameters were found to depend on the EBI dose having a fixed incident beam of energy 7.5 MeV. At different doses (500, 1000, 1500 kGy) of EBI, the Schottky contacts were prepared and extracted their contact parameters by applying thermionic emission and Cheung models. Remarkably, the tuning of ΦB was observed as a function of EBI dose. The improved n with increased ΦB is seen for all the EBI doses. As a consequence of which the thermionic emission is more favored. However, the competing transport mechanisms such as space charge limited emission, tunneling and tunneling through the trap states were ascribed due to n > 1. The analysis of XPS spectra have shown the presence of native oxide and increased radiation induced defect states. The thickness variation in the MS interface contributing to Schottky contact behavior is discussed. This study explains a new technique to tune Schottky contact parameters by metal deposition on the electron beam irradiated n-Si wafers.

  4. Measurements of particle emission from discharge sites in Teflon irradiated by high energy electron beams

    NASA Technical Reports Server (NTRS)

    Hazelton, R. C.; Churchill, R. J.; Yadlowsky, E. J.

    1979-01-01

    Anomalous behavior of synchronous orbit satellites manifested by overall degradation of system performance and reduced operating life is associated with electrical discharges resulting from differential charging of the spacecraft surface by fluxes of high energy electrons. During a laboratory simulation silver-backed Teflon samples have been irradiated by electron beams having energies in the range 16-26 keV. Charged particles emitted from the resultant electrical discharges have been measured with a biased Faraday cup and retarding potential analyser. Measurements indicate the presence of two distinct fluxes of particles, the first being an early pulse (0-600ns) of high energy (about 7keV) electrons, while the second is a late pulse (1-5 microseconds) of low energy electrons (less than 1eV) and ions (70eV) leaving the discharge site as a quasi plasma. Calculations indicate an electrostatic field as the dominant accelerating mechanism for charged particles.

  5. Measurements of particle emission from discharge sites in Teflon irradiated by high energy electron beams

    NASA Technical Reports Server (NTRS)

    Hazelton, R. C.; Churchill, R. J.; Yadlowsky, E. J.

    1979-01-01

    Anomalous behavior of synchronous orbit satellites manifested by overall degradation of system performance and reduced operating life is associated with electrical discharges resulting from differential charging of the spacecraft surface by fluxes of high energy electrons. During a laboratory simulation silver-backed Teflon samples have been irradiated by electron beams having energies in the range 16-26 keV. Charged particles emitted from the resultant electrical discharges have been measured with a biased Faraday cup and retarding potential analyser. Measurements indicate the presence of two distinct fluxes of particles, the first being an early pulse (0-600ns) of high energy (about 7keV) electrons, while the second is a late pulse (1-5 microseconds) of low energy electrons (less than 1eV) and ions (70eV) leaving the discharge site as a quasi plasma. Calculations indicate an electrostatic field as the dominant accelerating mechanism for charged particles.

  6. Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

    NASA Astrophysics Data System (ADS)

    Bee, Soo-Tueen; Sin, Lee Tin; Ratnam, C. T.; Haraveen, K. J. S.; Tee, Tiam-Ting; Rahmat, A. R.

    2015-10-01

    In this study, the effects of electron beam irradiation on the properties of copper(II) oxide when added to low-density polyethylene (LDPE) blends were investigated. It was found that the addition of low loading level of copper(II) oxide (⩽2 phr) to LDPE results in significantly poorer gel content and hot set results. However, the incorporation of higher loading level of copper(II) oxide (⩾3 phr) could slightly increase the degree of crosslinking in all irradiated LDPE composites. This is due to the fact that higher amounts of copper(II) oxide could slightly induce the formation of free radicals in LDPE matrix. Besides, increasing irradiation doses was also found to gradually increase the gel content of LDPE composites by generating higher amounts of free radicals. As a consequence, these higher amounts of free radicals released in the LDPE matrix could significantly increase the degree of crosslinking. The addition of copper(II) oxide could reduce the tensile strength and fracture strain (elongation at break) of LDPE composites because of poorer interfacial adhesion effect between copper(II) oxide particles and LDPE matrix. Meanwhile, increasing irradiation doses on all copper(II) oxide added LDPE composites could marginally increase the tensile strength. In addition, increasing irradiation dose could enhance the thermal stability of LDPE composites by increasing the decomposition temperature. The oxidation induction time (OIT) analysis showed that, because of the crosslinking network in the copper(II) oxide added LDPE composites, oxidation reaction is much delayed.

  7. Volatile compounds and odor traits of dry-cured ham (Prosciutto crudo) irradiated by electron beam and gamma ray

    USDA-ARS?s Scientific Manuscript database

    Prosciutto crudo were irradiated at 0, 3 and 6kGy by gamma ray (GR) and electron beam (EB), respectively. The odor scores and volatile compounds were examined after 7 days storage at 4'. Volatile compounds from samples without and with irradiation at 6kGy were analyzed by GC-MS. Fifty-nine compounds...

  8. Synergistic Effects of Combined Electron Beam and Microwave Irradiation on Microorganisms Inactivation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Martin, Diana I.; Manaila, Elena N.; Togoe, Iulian I.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Ighigeanu, Adelina I.; Oproiu, Constantin V.

    2007-04-01

    Comparative results obtained by using separate and combined electron beam (EB) and microwave (MW) on microorganisms inactivation in natural products such as minced beef, wheat bran, wheat flour and sewage sludge are presented. The combination of advantages of both, EB and MW, in microbiological decontamination process, i.e. the EB high efficiency and MW high selectivity and volumetric heating assures higher material microbiological safety, extends the kind range of microorganisms to be inactivated, reduces the absorbed dose level and irradiation time, and decreases the process costs.

  9. Synthesis and characterization of silver/diatomite nanocomposite by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Hanh, Truong Thi; Thu, Nguyen Thi; Quoc, Le Anh; Hien, Nguyen Quoc

    2017-10-01

    Silver nanoparticles (AgNPs) with diameter about 9 nm were deposited on diatomite by irradiation under electron beam of diatomite suspension containing 10 mM AgNO3 in 1% chitosan solution, at the dose of 20.2 kGy. The AgNPs/diatomite nanocomposite was characterized by UV-Vis spectroscopy, TEM image and energy dispersive X-ray spectroscopy (EDX). The antibacterial activity of the AgNPs/diatomite against E. coli and S. aureus was evaluated by reduction of bacterial colonies on spread plates and inhibition zone diameter on diffusion disks.

  10. Formation of a crystalline phase in amorphous hydrogenated carbon-germanium films by electron beam irradiation

    SciTech Connect

    Tyczkowski, J.; Pietrzyk, B.; Mazurczyk, R.; Polanski, K.; Balcerski, J.; Delamar, M.

    1997-11-01

    The influence of electron beam irradiation on morphology of plasma deposited amorphous hydrogenated carbon-germanium films produced from tetramethylgermanium in a three-electrode af reactor has been studied. It has been found that the insulating films are insensitive to this treatment, whereas a crystalline phase occurs in the semiconducting films. Although the molar content of germanium in these films amounts only to about 0.2, the crystalline phase is composed of pure germanium nanocrystals which contain about 70{percent} of the whole amount of germanium existing in the films. The nanocrystals are agglomerated in globules of 50{endash}500 nm in diameter. {copyright} {ital 1997 American Institute of Physics.}

  11. Influences of surfactants on the preparation of copper nanoparticles by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Zhou, Ruimin; Wu, Xinfeng; Hao, Xufeng; Zhou, Fei; Li, Hongbin; Rao, Weihong

    2008-02-01

    Electron beam radiation was applied to prepare nano-size copper in water system using polyvinyl alcohol, sodium dodecyl benzene sulfonate, gluten and polyethylene glycol as the surfactants, respectively. The irradiated products were characterized by XRD, TEM and LSPSDA. The XRD and TEM showed that relative pure copper products with an average size of 20 nm, 40 nm and 20 nm can be obtained by using gluten, PEG and SDBS as surfactant, respectively. An admixture of copper and cuprous oxide was obtained in PVA system. The LSPSDA showed that the size of the Cu nanoparticles decreased with increasing the glutin concentration.

  12. Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium in powdered weaning food by electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Hong, Yun-Hee; Park, Ji-Yong; Park, Jong-Hyun; Chung, Myong-Soo; Kwon, Ki-Sung; Chung, Kyungsook; Won, Misun; Song, Kyung-Bin

    2008-09-01

    Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium were evaluated in powdered weaning food using electron-beam irradiation. E. sakazakii, B. cereus, and S. typhimurium were eliminated by irradiation at 16, 8, and 8 kGy, respectively. The D10-vlaues of E. sakazakii, B. cereus, and S. typhimurium inoculated on powdered weaning food were 4.83, 1.22, and 0.98 kGy, respectively. The results suggest that electron-beam irradiation should inhibit the growth of pathogenic bacteria on baby food without impairing qualities.

  13. Effect of electron beam irradiation on the properties of natural rubber (NR)/styrene-butadiene rubber (SBR) blend

    NASA Astrophysics Data System (ADS)

    Manshaie, R.; Nouri Khorasani, S.; Jahanbani Veshare, S.; Rezaei Abadchi, M.

    2011-01-01

    In this study, physico-mechanical properties of NR/SBR blends cured by electron beam irradiation and sulfur were compared. The NR/SBR blends were prepared using a two-roll mill. Electron beam irradiations of 100-400 kGy were applied to cure the blends and changes in physico-mechanical properties were studied as a function of irradiation. Also, oil resistance and the effect of thermal ageing on mechanical properties of the blends were investigated. The results show that the irradiated blends have better mechanical properties than those cured by sulfur system. The irradiation cured samples also exhibited better heat stability than the sulfur cured samples. The blend cured by the highest dose shows the lowest swelling and high oil resistance compared with the other samples cured by irradiation.

  14. How does electron beam irradiation dose affect the chemical and antioxidant profiles of wild dried Amanita mushrooms?

    PubMed

    Fernandes, Ângela; Barreira, João C M; Antonio, Amilcar L; Rafalski, Andrzej; Oliveira, M Beatriz P P; Martins, Anabela; Ferreira, Isabel C F R

    2015-09-01

    As with all mushrooms, Amanita species demonstrates several conservation problems, due to a post-harvest life limited to a few days. Drying is one of the most commonly used methods in mushroom preservation. Food irradiation is another possible way to improve food quality and insure its security. Among the emerging irradiation technologies, electron beam irradiation has wide applications, allowing for high throughput, wide flexibility and potential, without any negative effect on the environment. The effects of different electron beam irradiation doses in Amanita genus, were assessed by measuring the changes produced on a wide variety of nutritional, chemical and antioxidant indicators. The evaluated profiles indicated differences between non-irradiated and irradiated samples, however a high similarity was observed among different doses. This finding advises that the highest assayed dose (10 kGy) be applied, ensuring a higher effectiveness from a decontamination and disinfestation perspective, without having any stronger effects than those observed by the lower doses.

  15. Physical properties of biaxially oriented poly(ethylene terephtalate) irradiated at different temperatures and doses with electron beam

    NASA Astrophysics Data System (ADS)

    Adem, E.; Hernández-Sampelayo, A. Rubio; Báez, J. E.; Miranda, J.; Labrada-Delgado, G. J.; Marcos-Fernández, A.

    2017-01-01

    The electron beam irradiation of a biaxially oriented PET film was carried out in air over a range of 50-3000 kGy at different temperatures and a dose rate of 4.48 kGy min-1. The effects of the irradiation at temperatures above and below the glass transition temperature (Tg) on the thermal and mechanical properties were studied. Melting temperature decreased slightly and crystallization temperature and crystallinity increased significantly with the increase in dose, more at higher irradiation temperature, whereas Tg did not show any significant change with dose or temperature. Mechanical properties were adversely affected by irradiation. Stress and strain at break were strongly reduced, more at higher irradiation temperature, and Young's Modulus slightly increased with the increase in dose. The changes in properties were related to the chain scission produced by the electron beam irradiation leading to a decrease in molecular weight.

  16. Dose effects in electron beam irradiation of DNA-complex thin films

    SciTech Connect

    Li, W.; Jones, R.; Spaeth, H.; Steckl, A. J.

    2010-08-09

    Electron beam irradiation of double-stranded DNA (dsDNA)-surfactant thin films was investigated. Irradiation caused dissociation, leading to increasing thin film solubility in water and degradation of dsDNA. These two effects produced a maximum concentration of dsDNA in aqueous solution at 400 {mu}C/cm{sup 2} dose. These properties resulted in dual-mode resist characteristics of the DNA-surfactant films. At low dose, the DNA films functioned as positive resist while at high dose they worked as negative resist. The transition between the two regimes also occurred at 400 {mu}C/cm{sup 2}. This implies that the cross-linking process (typical for negative resists) first requires the dissociation of the DNA-surfactant complex.

  17. Inactivation of feline calicivirus as a surrogate for norovirus on lettuce by electron beam irradiation.

    PubMed

    Zhou, Fanghong; Harmon, Karen M; Yoon, Kyoung-Jin; Olson, Dennis G; Dickson, James S

    2011-09-01

    Caliciviridae, including norovirus, are considered important sources of human gastroenteritis. As leafy green vegetables are commonly consumed without additional processing, it is important to evaluate interventions to reduce the presence of human pathogens in these products. Feline calicivirus was used as a model for small round structured viruses on lettuce. The lettuce was inoculated by immersion to simulate contamination from irrigation or wash water. The inoculated lettuce was then exposed to electron beam irradiation at various dose levels to determine survival. The D₁₀-value of the calicivirus on lettuce was determined to be 2.95 kGy. Irradiation to reduce bacterial pathogens on cut lettuce could also reduce the risk associated with small round structured viruses on lettuce.

  18. Effect of electron beam irradiation on the structural properties of PVA/V 2O 5 xerogel

    NASA Astrophysics Data System (ADS)

    Ali, Z. I.; Ali, F. A.; Hosam, A. M.

    2009-05-01

    Poly(vinylalcohol) (PVA)/vanadium pentoxide xerogel (VXG) composites were prepared and exposed to different electron beam irradiation doses. Changes in the structural properties, crystallinity degree of composites with increasing irradiation doses and VXG content were subsequently investigated using the Fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) techniques. The crystallinity degree of the PVA matrix was found to decrease markedly due to VXG addition and/or irradiation process.

  19. Effect of electron beam irradiation on the structural properties of PVA/V(2)O(5) xerogel.

    PubMed

    Ali, Z I; Ali, F A; Hosam, A M

    2009-05-01

    Poly(vinylalcohol) (PVA)/vanadium pentoxide xerogel (VXG) composites were prepared and exposed to different electron beam irradiation doses. Changes in the structural properties, crystallinity degree of composites with increasing irradiation doses and VXG content were subsequently investigated using the Fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) techniques. The crystallinity degree of the PVA matrix was found to decrease markedly due to VXG addition and/or irradiation process.

  20. Evaluation of some selected vaccines and other biological products irradiated by gamma rays, electron beams and X-rays

    NASA Astrophysics Data System (ADS)

    May, J. C.; Rey, L.; Lee, Chi-Jen

    2002-03-01

    Molecular sizing potency results are presented for irradiated samples of one lot of Haemophilus b conjugate vaccine, pneumococcal polysaccharide type 6B and typhoid vi polysaccharide vaccine. The samples were irradiated (25 kGy) by gamma rays, electron beams and X-rays. IgG and IgM antibody response in mice test results (ELISA) are given for the Hib conjugate vaccine irradiated at 0°C or frozen in liquid nitrogen.

  1. Laser light-stimulated exoelectron emission from solid Ar pre-irradiated by an electron beam

    NASA Astrophysics Data System (ADS)

    Gumenchuk, G. B.; Belov, A. G.; Savchenko, E. V.; Ponomaryov, A. N.; Bondybey, V. E.

    2007-06-01

    Spatially separated stable charge centers, self-trapped holes and trapped electrons, were generated in Ar cryocrystals by a low-energy electron beam. A combination of the cathodoluminescence (CL) and photon-stimulated exoelectron emission (PSEE) methods was used to monitor center formation and a selected relaxation channel—exoelectron emission. It was found that photon-promoted electron current decreased exponentially under irradiation with the laser operating in the visible range. The influence of the laser parameters (power and wavelength) on the characteristic lifetime of exoelectron emission is discussed. Effective bleaching of the low-temperature peaks of thermally stimulated exoelectron emission by the laser light in a visible range is observed.

  2. Fractal parameterization analysis of ferroelectric domain structure evolution induced by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Maslovskaya, A. G.; Barabash, T. K.

    2017-01-01

    The article presents some results of fractal analysis of ferroelectric domain structure images visualized with scanning electron microscope (SEM) techniques. The fractal and multifractal characteristics were estimated to demonstrate self-similar organization of ferroelectric domain structure registered with static and dynamic contrast modes of SEM. Fractal methods as sensitive analytical tools were used to indicate degree of domain structure and domain boundary imperfections. The electron irradiation-induced erosion effect of ferroelectric domain boundaries in electron beam-stimulated polarization current mode of SEM is characterized by considerable raising of fractal dimension. For dynamic contrast mode of SEM there was revealed that complication of domain structure during its dynamics is specified by increase in fractal dimension of images and slight raising of boundary fractal dimension.

  3. Comparison of Quality of Bologna Sausage Manufactured by Electron Beam or X-Ray Irradiated Ground Pork

    PubMed Central

    Shin, Mee-Hye

    2014-01-01

    Ground lean pork was irradiated by an electron beam or X-rays to compare the effects of two types of radiation generated by a linear accelerator on the quality of Bologna sausage as a model meat product. Raw ground lean pork was vacuum packaged at a thickness of 1.5 cm and irradiated at doses of 2, 4, 6, 8, or 10 kGy by an electron beam (2.5 MeV) or X-rays (5 MeV). Solubility of myofibrillar proteins, bacterial counts, and thiobarbituric acid reactive substance (TBARS) values were determined for raw meat samples. Bologna sausage was manufactured using the irradiated lean pork, and total bacterial counts, TBARS values, and quality properties (color differences, cooking yield, texture, and palatability) were determined. Irradiation increased the solubility of myofibrillar proteins in a dose-dependent manner (p<0.05). Bacterial contamination of the raw meat was reduced as the absorbed dose increased, and the reduction was the same for both radiation types. Differences were observed only between irradiated and non-irradiated samples (p<0.05). X-ray irradiation may serve as an alternative to gamma irradiation and electron beam irradiation. PMID:26761284

  4. Comparison of Quality of Bologna Sausage Manufactured by Electron Beam or X-Ray Irradiated Ground Pork.

    PubMed

    Shin, Mee-Hye; Lee, Ju-Woon; Yoon, Young-Min; Kim, Jong Heon; Moon, Byeong-Geum; Kim, Jae-Hun; Song, Beom-Suk

    2014-01-01

    Ground lean pork was irradiated by an electron beam or X-rays to compare the effects of two types of radiation generated by a linear accelerator on the quality of Bologna sausage as a model meat product. Raw ground lean pork was vacuum packaged at a thickness of 1.5 cm and irradiated at doses of 2, 4, 6, 8, or 10 kGy by an electron beam (2.5 MeV) or X-rays (5 MeV). Solubility of myofibrillar proteins, bacterial counts, and thiobarbituric acid reactive substance (TBARS) values were determined for raw meat samples. Bologna sausage was manufactured using the irradiated lean pork, and total bacterial counts, TBARS values, and quality properties (color differences, cooking yield, texture, and palatability) were determined. Irradiation increased the solubility of myofibrillar proteins in a dose-dependent manner (p<0.05). Bacterial contamination of the raw meat was reduced as the absorbed dose increased, and the reduction was the same for both radiation types. Differences were observed only between irradiated and non-irradiated samples (p<0.05). X-ray irradiation may serve as an alternative to gamma irradiation and electron beam irradiation.

  5. Decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process.

    PubMed

    Mohd Nasir, Norlirubayah; Teo Ming, Ting; Ahmadun, Fakhru'l-Razi; Sobri, Shafreeza

    2010-01-01

    The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD(5) removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD(5) removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.

  6. Large-area electron beam irradiation for surface polishing of cast titanium.

    PubMed

    Tokunaga, Junko; Kojima, Tetsuya; Kinuta, Soichiro; Wakabayashi, Kazumichi; Nakamura, Takashi; Yatani, Hirofumi; Sohmura, Taiji

    2009-09-01

    Cast titanium is a known hard-to-polish material, and its final polishing step is a perpetual challenge. The best way to tackle this challenge lies in automatic and non-mechanical polishing methods. Against this background, the suitability of large-area electron beam (EB) irradiation was examined in this study. In parallel, the optimum condition for efficient surface polishing was investigated. Cast titanium specimens were prepared, whereby their surface glossiness, surface roughness, and corrosion resistance were measured before and after EB irradiation. After EB irradiation, favorable results were observed: the cast titanium surface became smooth, the glossiness increased, and corrosion resistance was enhanced. These results were attributed to the low heat conductivity of titanium. With mechanical polishing, this property results in temperature rise and burnout reaction of the titanium surface with oxygen and the abrasives. However, during EB irradiation, the low heat conductivity of titanium was an advantage in raising the surface temperature to the melting point, such that a smooth surface was yielded after solidification. Based on the results obtained, automatic polishing by EB seemed to be a suitable polishing method for metal frameworks of removable dentures, and an efficient one too by saving time and effort.

  7. Conductivities and curing properties of electron-beam-irradiated anisotropic conductive films

    NASA Astrophysics Data System (ADS)

    Shin, Tae Gyu; Lee, Inhyuk; Kim, Jae yong

    2012-07-01

    Radiation-curable acrylated epoxy oligomer was irradiated by using an electron beam (E-beam) with dosages of 5, 10, 20, 40, 80, 200, 400, and 550 kGy to investigate the electrical and the physical properties of anisotropic conductive films (ACFs) and to evaluate the potential application of radiation technology to flip-chip package processing. An ACF is an insulating epoxy matrix containing conducting particles that keep the electrical conductivity along the out-of-plane direction and the insulation property along the in-plane direction. The contact resistance between ACF joints cured by using an E-beam irradiation of 80 kGy was measured under a constant bonding pressure of 2 kgf/cm2 to demonstrate the effects of pad pitch size and the number of added conductive particles in the epoxy resin. Three types of PCBs, 1000-, 500-, and 100-µm pad pitches, were employed while the E-beam curable epoxy resin was mixed with conductive particles in a weight ratio of 10:1. The measured average contact resistance was 0.24 Ω with a minimum of 0.06 Ω for the samples prepared with a 100-µm pad pitch size, which is compatible with or lower than the values obtained from thermally-cured commercial ACFs. Our results demonstrate that an E-beam is an effective radiation method for curing epoxy resins at low temperatures in a short time and can be employed as a new technique for bonding circuits in high-density electric devices.

  8. Application of electron beam irradiation combined to conventional treatment to treat industrial effluents

    NASA Astrophysics Data System (ADS)

    Duarte, C. L.; Sampa, M. H. O.; Rela, P. R.; Oikawa, H.; Cherbakian, E. H.; Sena, H. C.; Abe, H.; Sciani, V.

    2000-03-01

    A preliminary study to combine electron beam irradiation process with biological treatment was carried out. Experiments were conducted using samples from a governmental wastewater treatment plant (WTP) that receives about 20% of industrial wastewater, with the objective of destroying the refractory organic pollutants and to obtain a better performance of this plant. Samples from five different steps of WTP were collected and irradiated in the electron beam accelerator in a batch system with 5.0, 10.0 and 20.0 kGy doses. The main results showed a removal of 99% of all organic compound analysed in the industrial receiver unit (IRU) effluent and in the coarse bar screen (CBS) effluent with a 20 kGy dose, and for the medium bar screen (MBS) and primary sedimentation (PS) effluent a 10 kGy dose was sufficient. In the case of final effluent (FE), a dose of 5 kGy removed the remaining organic compounds and dyes present after biological treatment.

  9. Electron beam irradiation of sun-dried apricots for quality maintenance

    NASA Astrophysics Data System (ADS)

    Wei, Ming; Zhou, Linyan; Song, Hongbo; Yi, Jianyong; Wu, Bin; Li, Yaru; Zhang, Le; Che, Fengbin; Wang, Zhidong; Gao, Meixu; Li, Shurong

    2014-04-01

    The chemical, sensory, and microbial quality parameters of electron beam (EB)-irradiated and non-irradiated sun-dried apricots were periodically evaluated to optimize the EB irradiation of sun-dried apricots for quality maintenance. The sun-dried apricots were treated with 1.0, 2.0, 3.0, 4.0, and 5.0 kGy of EB and subsequently stored at ambient temperature. EB treatment at 1.0-3.0 kGy proved to be beneficial for retaining high levels of β-carotene, ascorbic acid, titratable acidity, total sugars, and color without any significant effect on sensory properties. Doses of 1.0-3.0 kGy retained the β-carotene content of sun-dried apricots to 8.21%, 9.27%, and 10.43% compared with 6.09% in control samples after 10 months of storage. After 10 months of storage, the maximum losses of ascorbic acid were 37.8% in control samples and 35.5% in 3.0 kGy-irradiated samples. Titratable acidity and total sugars were significantly enhanced immediately after 1.0-3.0 kGy irradiation treatment, and both parameters showed no significant change after 10 months of storage. Samples subjected to EB treatment at 3.0 kGy maintained a high overall acceptability of sun-dried apricots. Decreased number of viable microorganisms to below detection limits were observed after 3.0 kGy irradiation, and compared with the control, the logarithmic reductions after 10 months of storage were 0.98 for yeast and mold count, as well as 1.71 for bacterial count.

  10. Comparison Study on Changes of Antigenicities of Egg Ovalbumin Irradiated by Electron Beam or X-Ray.

    PubMed

    Kim, Mi-Jung; Lee, Ju-Woon; Sung, Nak-Yoon; Kim, Su-Min; Hwang, Young-Jung; Kim, Jae-Hun; Song, Beom-Seok

    2014-01-01

    This study was conducted to compare the effects of two forms of radiation (electron and X-ray; generated by an electron beam accelerator) on the conformation and antigenic properties of hen's egg albumin, ovalbumin (OVA), which was used as a model protein. OVA solutions (2.0 mg/mL) were individually irradiated by electron beam or X-ray at the absorbed doses of 0 (control), 2, 4, 6, 8, and 10 kGy. No differences between the two forms of radiation on the structural properties of OVA were shown by spectrometric and electrophoretic analyses. The turbidity of OVA solution increased and the main OVA bands on polyacrylamide gels disappeared after irradiation, regardless of the radiation source. In competitive indirect enzyme-linked immunosorbent assay, OVA samples irradiated by electron beam or X-ray showed different immunological responses in reactions with monoclonal and polyclonal antibodies (immunoglobulin G) produced against non-irradiated OVA. The results indicate that electron beam irradiation and X-ray irradiation produced different patterns of structural changes to the OVA molecule.

  11. Effects of electron beam irradiation on tribological and physico-chemical properties of Polyoxymethylene copolymer (POM-C)

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Shahinur; Shaislamov, Ulugbek; Yang, Jong-Keun; Kim, Jong-Kuk; Yu, Young Hun; Choi, Sooseok; Lee, Heon-Ju

    2016-11-01

    Polyoxymethylene copolymer (POM-C) is an attractive and widely used engineering thermoplastic across many industrial sectors owing to outstanding physical, mechanical, self-lubricating and chemical properties. In this research work, the POM-C blocks were irradiated with 1 MeV electron beam energy in five doses (100, 200, 300, 500 and 700 kGy) in vacuum condition at room temperature. The tribological and physico-chemical properties of electron beam irradiated POM-C blocks have been analyzed using pin on disk tribometer, Raman spectroscopy, FTIR-ATR, gel content analysis, SEM-EDS (scanning electron microscopy-energy dispersive spectroscopy), surface profiler and contact angle analyzer. Electron beam irradiation at a dose of 100 kGy resulted in decrease of the friction coefficient of POM-C block due to well suited carbonization, cross-linking, free radicals formation and partial physical modification. It also showed the lowest surface roughness and highest water contact angle among all unirradiated and irradiated POM-C blocks. The irradiation dose at 200 kGy resulted in increase of friction coefficient due to less effective cross-linking, but the irradiation doses at 300, 500 and 700 kGy resulted in increase of the friction coefficient as compared to unirradiated POM-C block due to severe chain scission, chemical and physical structural degradation. The degree of improvement for tribological attribute relies on the electron beam surface dose delivered (energy and dose rate).

  12. Dosimetric evaluation of multi-sided irradiation on HDPE pipes under 2 MeV electron beam

    NASA Astrophysics Data System (ADS)

    Benny, P. G.; Khader, S. A.; Sarma, K. S. S.

    2014-03-01

    The use of electron beam technology has enabled the production of heat resistant pipe for hot water circulation. One of the difficulties in the irradiation of pipe products is the uneven penetration of electrons. Quality of the radiation process depends on radiation dose and homogeneity of the dose distribution, which becomes a major concern when treatments of circular objects like pipes are performed. One method to achieve uniformity in the absorbed dose in the product is to use multi-sided irradiation. The paper discusses the importance of dosimetry mapping in industrial electron beam radiation processing and outlines the challenges in delivering a uniform dose to cylindrical objects. In this study, HDPE pipe of 5 mm thickness of homogeneous material (40 mm outer diameter and 30 mm inner diameter) has been chosen for multi-sided irradiation under 2 MeV scanned electron beam from the ILU-6 accelerator.

  13. A comparative study on the effects of electron beam irradiation on imidacloprid-resistant and -susceptible Aphis gossypii (Hemiptera: Aphididae)

    NASA Astrophysics Data System (ADS)

    Yun, Seung-Hwan; Koo, Hyun-Na; Lee, Seon-Woo; Kim, Hyun Kyung; Kim, Yuri; Han, Bumsoo; Kim, Gil-Hah

    2015-07-01

    The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain.

  14. Post mastectomy chest wall irradiation using mixed electron-photon beams with or without isocentric technique.

    PubMed

    Hamdy, H K; Zikry, M S

    2008-01-01

    To describe our technique in delivering post mastectomy radiotherapy to chest wall using electron-photon mixed beam with or without isocentric application of the tangential photon portals, and to evaluate the associated acute and delayed morbidities. Twenty-two females with invasive breast cancer were subjected to modified radical mastectomy with adequate axillary dissection. All the patients have either tumour > or = 5 cm and/ or positive axillary nodes > 3. Chest wall was irradiated by a mixed beam of 6-Mev electrons (10Gy) and opposed tangential fields using 6 Mev-photons (36 Gy) followed by 6-Mev electrons boost to the scar of mastectomy for 4 Gy/2 fractions. We randomly allocated our patients to receive the photon beam with or without the isocentric technique. The mean dose to the planned target volume (PTV) by mixed beam was 44 Gy (96%) with a mean dose of 42 Gy (91%) to the overlying skin for the whole study group. In cases with right breast disease (17 cases), the mean right lung tissue volume within the PTV was 220 ml (15%). It was relatively higher with the non-iscocentric technique, 281 ml (19%), compared to the isocentric technique of 159 ml (10.5%). In cases with left breast disease (5 cases), the mean left lung volume within the PTV was 175 ml (14%). Larger volume of the lung tissue was included with the non-isocentric technique, 197 ml (16%) compared to the isocentric technique of 153 ml (12%). The mean scattered doses to the rest of the lung tissue, the rest of the heart in left breast cases, and the contra-lateral breast for the whole study group were 2.8 Gy, 1.8 Gy, and 1.4 Gy respectively and was comparable in both treatment arms. None of the cases developed any element of acute radiation related pneumonitis. Delayed radiation induced pneumonitis was seen in 2 cases (18%), with the chest wall treated with radiation with the non-isocentric technique. This study clearly demonstrated the utility of mixed beam in irradiating the chest wall after

  15. Fast crystallization of amorphous Gd2Zr2O7 induced by thermally activated electron-beam irradiation

    PubMed Central

    Huang, Zhangyi; Qi, Jianqi; Zhou, Li; Feng, Zhao; Yu, Xiaohe; Gong, Yichao; Yang, Mao; Shi, Qiwu; Wei, Nian; Lu, Tiecheng

    2015-01-01

    We investigate the ionization and displacement effects of an electron-beam (e-beam) on amorphous Gd2Zr2O7 synthesized by the co-precipitation and calcination methods. The as-received amorphous specimens were irradiated under electron beams at different energies (80 keV, 120 keV, and 2 MeV) and then characterized by X-ray diffraction and transmission electron microscopy. A metastable fluorite phase was observed in nanocrystalline Gd2Zr2O7 and is proposed to arise from the relatively lower surface and interface energy compared with the pyrochlore phase. Fast crystallization could be induced by 120 keV e-beam irradiation (beam current = 0.47 mA/cm2). The crystallization occurred on the nanoscale upon ionization irradiation at 400 °C after a dose of less than 1017 electrons/cm2. Under e-beam irradiation, the activation energy for the grain growth process was approximately 10 kJ/mol, but the activation energy was 135 kJ/mol by calcination in a furnace. The thermally activated ionization process was considered the fast crystallization mechanism. PMID:26648597

  16. Deep level transient spectroscopy study of electron traps in n-type GaAs after pulsed electron beam irradiation

    SciTech Connect

    Marrakchi, G.; Barbier, D.; Guillot, G.; Nouailhat, A.

    1987-10-01

    Electrical and deep level transient spectroscopy measurements on Schottky barriers were performed in order to characterize electrically active defects in n-type GaAs (Bridgman substrates or liquid-phase epitaxial layers) after pulsed electron beam annealing. Both surface damage and bulk defects were observed in the Bridgman substrates depending on the pulse energy density. No electron traps were detected in the liquid-phase epitaxial layers before and after annealing for an energy density of 0.4 J/cm/sup 2/. The existence of an interfacial insulating layer at the metal-semiconductor interface, associated with As out-diffusion during the pulsed electron irradiation, was revealed by the abnormally high values of the Schottky barrier diffusion potential. Moreover, two new electron traps with activation energy of 0.35 and 0.43 eV, called EP1 and EP2, were introduced in the Bridgman substrates after pulsed electron beam annealing. The presence of these traps, related to the As evaporation, was tentatively attributed to the decrease of the EL2 electron trap signal after 0.4-J/cm/sup 2/ annealing. It is proposed that these new defects states are due to the decomposition of the As/sub Ga/-As/sub i/ complex recently considered as the most probable defect configuration for the dominant EL2 electron trap usually detected in as-grown GaAs substrates.

  17. Increased tensile strength of carbon nanotube yarns and sheets through chemical modification and electron beam irradiation.

    PubMed

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

    2014-05-14

    The inherent strength of individual carbon nanotubes (CNTs) offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of 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 into that of sheets and yarns, where the bulk material strength is limited by intertube electrostatic attractions and slippage. The focus of this work was to assess postprocessing of CNT sheets and yarns to improve the macro-scale strength of these material forms. Both small-molecule functionalization and electron-beam irradiation were evaluated as means to enhance the tensile strength and Young's modulus of the bulk CNT materials. Mechanical testing revealed a 57% increase in tensile strength of CNT sheets upon functionalization compared with unfunctionalized sheets, while an additional 48% increase in tensile strength was observed when functionalized sheets were irradiated. Similarly, small-molecule functionalization increased tensile strength of yarn by up to 25%, whereas irradiation of the functionalized yarns pushed the tensile strength to 88% beyond that of the baseline yarn.

  18. Surface-and bulk-properties of EPDM rubber modified by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Majumder, Papiya Sen; Bhowmick, Anil K.

    1999-01-01

    Electron beam initiated grafting of trimethylol propane triacrylate (TMPTA) onto ethylene propylene diene monomer (EPDM) has been carried out over a wide range of irradiation doses (0-200 kGy) using a fixed concentration (10%) of TMPTA. The samples have been both surface and bulk modified. Infrared (IR) studies indicate increased peak absorbances at 1730, 1260, 1120 and 1019 cm -1 upto 50 kGy and hence increased CO and C-O-C concentrations. The results are further supported by X-ray photoelectron spectroscopy (XPS) studies. The surface energy of EPDM increases from 46.5 to 60.7 mJ/m 2 on irradiation of the surface modified samples to 50 kGy dose, due to increased contribution of γSAB and γS(-). The results have been explained with the help of IR and XPS data. The values of tensile strength of the surface modified samples have not changed very significantly, while the moduli values have increased at the cost of the elongation at break. DMTA studies have shown changes in Tg and tan δmax on modification of the surface. The surface morphology of the modified and irradiated samples reveals acrylate flow marks at high magnification.

  19. Tuning the magnetism of epitaxial cobalt oxide thin films by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Lan, Q. Q.; Zhang, X. J.; Shen, X.; Yang, H. W.; Zhang, H. R.; Guan, X. X.; Wang, W.; Yao, Y.; Wang, Y. G.; Peng, Y.; Liu, B. G.; Sun, J. R.; Yu, R. C.

    2017-07-01

    Tuning magnetic properties of perovskite thin films is a central topic of recent studies because of its fundamental significance. In this work, we demonstrated the modification of the magnetism of L a0.9C a0.1Co O3 (LCCO) thin films by introducing a stripelike superstructure in a controllable manner using electron beam irradiation (EBI) in a transmission electron microscope. The microstructure, electronic structure, strain change, and origin of magnetism of the LCCO thin films were studied in detail using aberration-corrected scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations based on density functional theory. The results indicate that the EBI-induced unit cell volume expansion accompanies the formation of oxygen vacancies and leads to the spin state transition of Co ions. The low spin state of C o4 + ions depress the stripelike superstructure, while higher spin states of Co ions with lower valences are conductive to the formation of "dark stripes". Our work clarifies the origin of magnetism of epitaxial LCCO thin films, benefiting a comprehensive understanding of correlated physics in cobalt oxide thin films.

  20. Electron beam irradiation pretreatment and enzymatic saccharification of used newsprint and paper mill wastes

    NASA Astrophysics Data System (ADS)

    Waheed Khan, A.; Labrie, Jean-Pierre; McKeown, Joseph

    Electron beam pretreatment of used newsprint, pulp, as well as pulp recovered from clarifier sludge and paper mill sludge, caused the dissociation of cellulose from lignin, and rendered them suitable for enzymatic hydrolysis. A maximum dose of 1 MGy for newsprint and 1.5—2.0 MGy for pulp and paper mill sludge was required to render cellulose present in them in a form which, could be enzymatically saccharified to 90% of completion. Saccharification approaching the theoretical yield was obtained in 2 days with a cellulolytic enzyme system obtained from Trichoderma reesei. As a result of irradiation, water soluble lignin breakdown products, NaOH- soluble lignin, free cellobiose, glucose, mannose, xylose and their polymers, and acetic acid were produced from these materials.

  1. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    NASA Astrophysics Data System (ADS)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  2. Simulation calculations of tetrachloroethylene decomposition in air mixtures under electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Chmielewski, A. G.; Bułka, S.; Zimek, Z.; Nichipor, H.

    2009-07-01

    Theoretical simulation calculations of tetrachloroethylene (PCE) decomposition in air mixtures under electron beam (EB) irradiation have been carried out based on the experimental results. A computer code Kinetic and a Gear method were used and 324 reactions and 76 species were considered. From calculated results, we learn that more than 99% PCE is decomposed at 4.4 kGy dose when the initial concentration of PCE is 322 ppm; concentrations of inorganic carbons (CO+CO 2) increases with the dose, and the relative carbon concentration of inorganic carbons is about 17% at 13.1 kGy; phosgene (COCl 2) and trichloroacetyl chloride (CCl 3COCl) are predicted as main organic products and are confirmed by the experimental results. The good agreement is obtained between the calculated results and the experimental data.

  3. How gamma-rays and electron-beam irradiation would affect the antimicrobial activity of differently processed wild mushroom extracts?

    PubMed

    Alves, M J; Fernandes, Â; Barreira, J C M; Lourenço, I; Fernandes, D; Moura, A; Ribeiro, A R; Salgado, J; Antonio, A; Ferreira, I C F R

    2015-03-01

    The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated. Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms. This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species. © 2014 The Society for Applied Microbiology.

  4. EMERGING TECHNOLOGY BULLETIN: REMOVAL OF PHENOL FROM AQUEOUS SOLUTIONS USING HIGH ENERGY ELECTRON BEAM IRRADIATION

    EPA Science Inventory

    Irradiation of aqueous solutions with high-energy electrons results in the formation of the aqueous electron, hydrogen radical, H-, and the hydroxyl radical, OH-. These reactive transient species initiate chemical reactions capable of destroying organic compounds in aqueous solut...

  5. Novel bismuth tri-iodide nanostructures obtained by the hydrothermal method and electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Aguiar, Ivana; Olivera, Alvaro; Mombrú, Maia; Bentos Pereira, Heinkel; Fornaro, Laura

    2017-01-01

    Bismuth tri-iodide is a layered compound semiconductor which has suitable properties as material for ionizing radiation detection devices. Monocrystals and polycrystalline thin films have been studied for this application, but only recently, the development of nanostructures of this compound has emerged as an interesting alternative for using such nanostructures in new types of radiation detectors or for including them in other applications. Considering this, we present in this work BiI3 nanoparticles successfully synthesized by the hydrothermal method, using a Teflon-lined stainless steel autoclave, at a temperature of 180 °C during 8-20 h, with BiCl3 and NaI as source materials. We characterized the nanoparticles by X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron dispersive spectroscopy (EDS). We obtained small rounded or hexagonal particles (10-20 nm in size) and larger structures. The maximum orientation of the nanostructures is along the (0 0 l) family planes and occurs after 16 h of synthesis, which arises as the best condition for obtaining BiI3 oriented nanostructures. When a 100 kV TEM electron beam was converged on the larger structures, we obtained highly oriented BiI3 hexagonal and rod shaped nanostructures. We found that particles' shape does not depend on the synthesis time. In addition, results were compared with the ones obtained for nanoparticles synthesized from solution. The present work is an advance in the synthesis of BiI3 nanostructures by the hydrothermal method, and is also the first step on seeking the amenable control of morphology and size of such structures using electron beam irradiation. This last process may be particularly appropriate for producing nanostructures for future applications in new devices.

  6. Thermal conductivity of graphene with defects induced by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Malekpour, Hoda; Ramnani, Pankaj; Srinivasan, Srilok; Balasubramanian, Ganesh; Nika, Denis L.; Mulchandani, Ashok; Lake, Roger K.; Balandin, Alexander A.

    2016-07-01

    We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is

  7. Effect of electron beam irradiation on the structural, thermal and optical properties of poly(vinyl alcohol) thin film

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Bahareth, Radiyah A.

    2013-04-01

    Poly(vinyl alcohol) (PVA) polymer was prepared using the casting technique. The obtained PVA thin films have been irradiated with electron beam doses ranging from 20 to 300 kGy. The resultant effect of electron beam irradiation on the structural properties of PVA has been investigated using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), while the thermal properties have been investigated using thermo-gravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T 0 and activation energy of thermal decomposition E a were calculated, results indicate that the PVA thin film decomposes in one main weight loss stage. Also, the electron beam irradiation in dose range 95-210 kGy led to a more compact structure of the PVA polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with electron beam dose has been determined using DTA. The PVA thermograms were characterized by the appearance of an endothermic peak due to melting. In addition, the transmission of the PVA samples and any color changes were studied. The color intensity Δ E was greatly increased with increasing electron beam dose, and was accompanied by a significant increase in the blue color component.

  8. Damage and strain in single-layer graphene induced by very-low-energy electron-beam irradiation

    SciTech Connect

    Murakami, Katsuhisa; Fujita, Jun-ichi; Kadowaki, Takuya

    2013-01-28

    From the analysis of the ratio of D peak intensity to G peak intensity in Raman spectroscopy, electron beam irradiation with energies of 100 eV was found to induce damage in single-layer graphene. The damage becomes larger with decreasing electron beam energy. Internal strain in graphene induced by damage under irradiation is further evaluated based on G peak shifts. The dose-dependent internal strain was approximately 2.22% cm{sup 2}/mC at 100 eV and 2.65 Multiplication-Sign 10{sup -2}% cm{sup 2}/mC at 500 eV. The strain induced by the irradiation showed strong dependence on electron energy.

  9. Effects of electron beam irradiation on chemical composition, antinutritional factors, ruminal degradation and in vitro protein digestibility of canola meal

    NASA Astrophysics Data System (ADS)

    Taghinejad-Roudbaneh, M.; Ebrahimi, S. R.; Azizi, S.; Shawrang, P.

    2010-12-01

    The aim of the present study was to determine the impact of electron beam (EB) irradiation at doses of 15, 30 and 45 kGy on the nutritional value of canola meal. The phytic acid and total glucosinolate content of EB-irradiated canola meal decreased as irradiation doses increased ( P<0.01). From in situ results, irradiation of canola meal at doses of 45 kGy decreased ( P<0.05) the effective degradibility of crude protein (CP) by 14%, compared with an untreated sample. In vitro CP digestibility of EB-irradiated canola meal at doses of 15 and 30 kGy was improved ( P<0.05). Electrophoresis results showed that napin and cruciferin sub-units of 30 and 45 kGy EB-irradiated canola meal were more resistant to degradation, compared with an untreated sample. Electron beam irradiation was effective in protecting CP from ruminal degradation and reducing antinutritional factors of irradiated canola meal.

  10. Formation of Pt-Zn Alloy Nanoparticles by Electron-Beam Irradiation of Wurtzite ZnO in the TEM

    NASA Astrophysics Data System (ADS)

    Lee, Sung Bo; Park, Jucheol; van Aken, Peter A.

    2016-07-01

    As is well documented, platinum nanoparticles, promising for catalysts for fuel cells, exhibit better catalytic activities, when alloyed with Zn. Pre-existing syntheses of Pt-Zn alloy catalysts are composed of a number of complex steps. In this study, we have demonstrated that nanoparticles of Pt-Zn alloys are simply generated by electron-beam irradiation in a transmission electron microscope of a wurtzite ZnO single-crystal specimen. The initial ZnO specimen is considered to have been contaminated by Pt during specimen preparation by focused ion beam milling. The formation of the nanoparticle is explained within the framework of ionization damage (radiolysis) by electron-beam irradiation and accompanying electrostatic charging.

  11. Does sterilization with fractionated electron beam irradiation prevent ACL tendon allograft from tissue damage?

    PubMed

    Schmidt, T; Grabau, D; Grotewohl, J H; Gohs, U; Pruß, A; Smith, M; Scheffler, S; Hoburg, A

    2017-02-01

    Allografts are frequently used for anterior cruciate ligament (ACL) reconstruction. However, due to the inherent risk of infection, a method that achieves complete sterilization of grafts is warranted without impairing their biomechanical properties. Fractionation of electron beam (FEbeam) irradiation has been shown to maintain similar biomechanical properties compared to fresh-frozen allografts (FFA) in vitro. Therefore, aim of this study was to evaluate the biomechanical properties and early remodelling of grafts that were sterilized with fractionated high-dose electron beam irradiation in an in vivo sheep model. ACL reconstruction was performed in 18 mature merino mix sheep. Sixteen were reconstructed with allografts sterilized with FEbeam irradiation (8 × 3.4 kGy) and two with FFA. Eight FFA from prior studies with identical surgical reconstruction and biomechanical and histological analyzes served as controls. Half of the animals were sacrificed at 6 and 12 weeks, and biomechanical testing was performed. Anterior-posterior laxity (APL) was assessed with an AP drawer test at 60° flexion, and load to failure testing was carried out. Histological evaluation of mid-substance samples was performed for descriptive analysis, cell count, crimp and vessel density. For statistical analysis a Kruskal-Wallis test was used for overall group comparison followed by a Mann-Whitney U test for pairwise comparison of the histological and biomechanical parameters. Biomechanical testing showed significantly decreased stiffness in FEbeam compared to FFA at both time points (p ≤ 0.004). APL was increased in FEbeam compared to FFA, which was significant at 6 weeks (p = 0.004). Median of failure loads was decreased in FEbeam grafts, with 12 reconstructions already failing during cyclic loading. Vessel density was decreased in FEbeam compared to FFA at both time points, with significant differences at 12 weeks (p = 0.015). Crimp length was significantly shorter in

  12. Effects of gamma and electron beam irradiation on the properties of calendered cord fabrics

    NASA Astrophysics Data System (ADS)

    Aytaç, Ayşe; Deniz, Veli; Şen, Murat; Hegazy, El-Sayed; Güven, Olgun

    2010-03-01

    The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are more sensitive even at low doses. Therefore, the effects of high energy irradiation on tyre cords have to be taken into consideration during tyre design reinforced with particularly Ny fabrics if pre-vulcanization with high energy radiation is to be applied.

  13. Electron-beam irradiation induced transformation of Cu2(OH)3NO3 nanoflakes into nanocrystalline CuO

    NASA Astrophysics Data System (ADS)

    Padhi, S. K.; Gottapu, S. N.; Krishna, M. Ghanashyam

    2016-05-01

    The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural transformation that validate CHN modification. High-resolution transmission electron microscopy imaging of e-beam irradiated regions unambiguously supports the growth of CuO nanoparticles (11.8(3.2) nm in diameter). This study demonstrates e-beam irradiation induced CHN depletion, subsequent nucleation and growth of nanocrystalline CuO regions well embedded in the parent burnt porous matrix which can be useful for miniaturized sensing applications. NaBH4 induced room temperature reduction of CHN to elemental Cu and its printability on paper was also demonstrated.The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural

  14. Influence of irradiation number of high current pulsed electron beam on the structure and properties of M50 steel

    NASA Astrophysics Data System (ADS)

    Xu, Fangjun; Tang, Guangze; Guo, Guangwei; Ma, Xinxin; Ozur, G. E.

    2010-08-01

    The influence of high current pulsed electron beam (HCPEB) irradiation numbers on the microstructure, wear and corrosion resistance properties of M50 steel was studied. The crystallize phase, surface morphology, hardness, oxidation wear and corrosion resistance of samples were analyzed using XRD, SEM, nanoindenter, wear tester and electrochemical corrosion tests. The results reveal that the hardness and wear resistance of irradiated samples decrease compared with untreated sample because of the increasing of austenite content in the melted layer; while the corrosion resistance of irradiated samples is higher than untreated sample.

  15. Particle-in-cell simulation of electron trajectories and irradiation uniformity in an annular cathode high current pulsed electron beam source

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Wang, Langping; Zhou, Guangxue; Wang, Xiaofeng

    2017-02-01

    In order to study electron trajectories in an annular cathode high current pulsed electron beam (HCPEB) source based on carbon fiber bunches, the transmission process of electrons emitted from the annular cathode was simulated using a particle-in-cell model with Monte Carlo collisions (PIC-MCC). The simulation results show that the intense flow of the electrons emitted from the annular cathode are expanded during the transmission process, and the uniformity of the electron distribution is improved in the transportation process. The irradiation current decreases with the irradiation distance and the pressure, and increases with the negative voltage. In addition, when the irradiation distance and the cathode voltage are larger than 40 mm and -15 kV, respectively, a uniform irradiation current distribution along the circumference of the anode can be obtained. The simulation results show that good irradiation uniformity of circular components can be achieved by this annular cathode HCPEB source.

  16. Effects of electron beam irradiation on physicochemical properties of corn flour and improvement of the gelatinization inhibition.

    PubMed

    Xue, Peiyu; Zhao, Yue; Wen, Chengrong; Cheng, Sheng; Lin, Songyi

    2017-10-15

    The properties and viscosity-reduction mechanism of corn flour irradiated by electron beam have not been understood properly. Here, we investigate the effects of electron beam irradiation (EBI) on the gelatinization and physicochemical properties of corn flour irradiated by 0-5.40kGy of electron beam. The total starch and crude fiber contents of corn flour decreased significantly (P<0.05) after EBI treatment, while the moisture and reducing sugar contents increased significantly (P<0.05). EBI caused perforations on the corn flour particle surfaces, and the irradiated parts of the particles would gradually peel off and afford smooth surfaces, spherical structures, and smaller sizes. Molecular chains of corn flour broke owing to EBI. After irradiation, the pasting peak viscosity decreased dramatically (P<0.01) from 1251.74 to 7.16Pa·s, showing that the gelatinization of corn flour was completely inhibited. Thus, EBI can be used to inhibit the gelatinization of corn flour, which may be beneficial for industrial and food formulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Triacylglycerols profiling as a chemical tool to identify mushrooms submitted to gamma or electron beam irradiation.

    PubMed

    Fernandes, Ângela; Barreira, João C M; Antonio, Amilcar L; Martins, Anabela; Ferreira, Isabel C F R; Oliveira, M Beatriz P P

    2014-09-15

    In order to define irradiation treatment as a routine conservation methodology, it is imperative to develop chemometric indicators with the ability to distinguish irradiated from unirradiated foodstuffs. Electron spin resonance, photostimulated luminescence and thermoluminescence methods were employed to monitor radiation-induced markers, as well as different chemical compounds produced from the lipidic fraction of different foodstuffs. Apart from these methods, the specificity of triacylglycerol profiles has previously been detected in mushroom species, as has the effect of irradiation treatment in the triacylglycerol profiles of chestnut. Accordingly, the feasibility of using this as a chemometric indicator of irradiated mushrooms was evaluated. In line with the obtained results in literature, the effects of each type of irradiation were significantly different, as can be concluded from the correlations among discriminant functions and variables within each statistical test. Triacylglycerol profiling proved to be a useful tool to detect irradiated mushrooms, independently of the species or irradiation source, especially for doses above 1 kGy.

  18. Postmastectomy Electron Beam Chest Wall Irradiation in Women With Breast Cancer: A Clinical Step Toward Conformal Electron Therapy

    SciTech Connect

    Kirova, Youlia M. Campana, Francois; Fournier-Bidoz, Nathalie; Stilhart, Anne; Dendale, Remi; Bollet, Marc A.; Fourquet, Alain

    2007-11-15

    Purpose: Electron beam radiotherapy of the chest wall with or without lymph node irradiation has been used at the Institut Curie for >20 years. The purpose of this report was to show the latest improvements of our technique developed to avoid hot spots and improve the homogeneity. Methods and Materials: The study was split into two parts. A new electron irradiation technique was designed and compared with the standard one (dosimetric study). The dose distributions were calculated using our treatment planning software ISIS (Technologie Diffusion). The dose calculation was performed using the same calculation parameters for the new and standard techniques. Next, the early skin toxicity of our new technique was evaluated prospectively in the first 25 patients using Radiation Therapy Oncology Group criteria (clinical study). Results: The maximal dose found on the five slices was 53.4 {+-} 1.1 Gy for the new technique and 59.1 {+-} 2.3 Gy for the standard technique. The hot spots of the standard technique plans were situated at the overlap between the internal mammary chain and chest wall fields. The use of one unique field that included both chest wall and internal mammary chain volumes solved the problem of junction. To date, 25 patients have been treated with the new technique. Of these patients, 12% developed Grade 0, 48% Grade 1, 32% Grade 2, and 8% Grade 3 toxicity. Conclusions: This report describes an improvement in the standard postmastectomy electron beam technique of the chest wall. This new technique provides improved target homogeneity and conformality compared with the standard technique. This treatment was well tolerated, with a low rate of early toxicity events.

  19. In situ transmission-electron-microscopy investigation of melting in submicron Al-Si alloy particles under electron-beam irradiation.

    PubMed

    Yokota, Takeshi; Murayama, M; Howe, J M

    2003-12-31

    In situ heating and electron-beam irradiation in the transmission electron microscope were performed to study melting of submicron Al-11.6 at. % Si particles supported on a C thin film. It was found that electron irradiation could be used to melt the particles, even when the hot-stage sample holder was kept at a much lower temperature ( approximately 125 degrees C) than the initial melting point of the particles. Comparison between the experimentally observed melting behavior and analytical calculations indicate that melting of the submicron Al-Si particles under electron-beam irradiation is caused by a temperature rise due to electron thermal spikes in the particles and poor thermal conduction away from the particles. These results have important implications in transmission electron microscopy studies of nanoparticles supported on thin films or poorly conducting substrates.

  20. Chlorinated hydrocarbons and PAH decomposition in dry and humid air by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Nichipor, H.; Dashouk, E.; Yacko, S.; Chmielewski, A. G.; Zimek, Z.; Sun, Y.

    2002-11-01

    The mechanism and kinetics of CCl 4; CH 2Cl 2; C 2HCl 3; C 2H 2Cl 2; C 2H 5Cl and polycyclic aromatic hydrocarbons (PAH), e.g. naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and benzo(a)pyrene, decomposition have been investigated in dry and humid air under the influence of electron beam irradiation, by computer simulation based on established theoretical models. The experimental data published in the literature and the results of calculations confirmed an assumption that thermalized electron dissociative attachment reactions are an important part of the chlorinated VOCs decomposition process. The exception is CH 2Cl 2 where the decomposition process is initiated by nitrogen atoms and N 2+ ions. A chain reaction was observed in the case of C 2HCl 3 and C 2H 2Cl 2 decomposition, where the dose necessary for 90% reduction is below 10 kGy. In contrast to the chlorinated VOC's, PAHs in humid air were primarily decomposed by OH radical's interactions. When initial PAH concentration was ⩽100 ppm the dose necessary for 90% reduction was below 10 kGy.

  1. Chlorinated aliphatic and aromatic VOC decomposition in air mixture by using electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Chmielewski, A. G.; Sun, Yong-Xia; Bułka, S.; Zimek, Z.

    2004-09-01

    Chlorinated aliphatic and aromatic hydrocarbons, which are emitted from coal power station and waste incinerators, are very harmful to the environment and human health. Recent studies show that chlorinated aliphatic and aromatic hydrocarbons are suspected to be the precursors of dioxin's formation. Dioxin's emission into atmosphere will cause severe environmental problems by ecology contamination. l,4-dichlorobenzene(l,4-DCB) and cis-dichloroethylene( cis-DCE) were chosen as representative chlorinated aromatic and aliphatic compounds, respectively. Their decomposition was investigated by electron beam irradiation. The experiments were carried out "in batch" system. It is found that over 97% cis-DCE is decomposed having an initial concentration of 661 ppm. G-values of cis-DCE decomposition vary from 10 to 28 (molecules/100 eV) for initial concentration of 270-1530 ppm cis-DCE. The decomposition is mainly caused by secondary electron attachment and Cl addition reactions. Comparing with cis-DCE, 1,4-DCB decomposition needs higher absorbed dose. G-value of 1,4-DCB is below 4 molecules/100 eV.

  2. Improving the microbiological quality and safety of fresh-cut tomatoes by low-dose electron beam irradiation.

    PubMed

    Schmidt, Heather Martin; Palekar, Mangesh P; Maxim, Joseph E; Castillo, Alejandro

    2006-03-01

    The effect of electron beam irradiation on microbiological quality and safety of fresh-cut tomatoes was studied. Fresh tomatoes were obtained from a local supplier and then cut into cubes that were separated from the stem scars. Both cubes and stem scars were inoculated with a rifampin-resistant strain of either Salmonella Montevideo or Salmonella Agona, separated into treatment groups, and treated by electron beam irradiation at 0.0 (control), 0.7, or 0.95 kGy. The effect of electron beam irradiation on Salmonella, lactic acid bacteria, yeast, and mold counts and pH of tomato cubes and stem scars was determined over a 15-day storage period at 4 degrees C. Results indicated that although irradiation treatment significantly reduced most microbial populations on tomato samples, there were no differences in the reduction of microbial populations between treatments of 0.7 and 0.95 kGy. Irradiation at either dose resulted in a significant reduction in Salmonella when compared with the control (P < 0.05). Lactic acid bacteria, yeasts, and molds were more resistant to irradiation than were Salmonella. No differences were detected between the two Salmonella serotypes in response to irradiation treatment. These results indicate that irradiation at doses of at least 0.7 kGy can be used for pathogen reduction in fresh-cut tomatoes. If the use of doses greater than 1 kGy were approved, this technology might be very effective for use in fresh-cut tomatoes to eliminate significant populations of pathogens and to ensure the microbial quality of the product.

  3. The effect of high-energy electron-beam irradiation on microstructural modification of a high-speed steel roll

    NASA Astrophysics Data System (ADS)

    Suh, Dongwoo; Lee, Sunghak; Koo, Yangmo; Lee, Hui Choon

    1996-10-01

    The purpose of this study is to investigate the microstructural modification in a high-speed steel (HSS) roll irradiated with an accelerated high-energy electron beam. The HSS roll samples were irradiated at the beam travel speeds of 2.5 to 25 mm/s using an electron accelerator (1.4 MeV). The microstructure was examined with a scanning electron microscope (SEM) capable of in situ fracture testing and simultaneous measurement of the apparent fracture toughness. Irradiation changed the matrix phase from tempered martensite to a mixture of retained austenite and martensite. Coarse primary carbides were partially or completely dissolved, depending on the heat input. Irradiation greatly improved the fracture properties because of the presence of retained austenite, which could retard crack propagation, although hardness was decreased. Occasional interior quench cracks were found in the heat-affected region. Appropriate processing methods, such as pre- or postirradiation, were suggested. A heat transfer analysis of the irradiated surface layer was also carried out to elucidate the influence of the irradiation parameters on the microstructure.

  4. Domain switching by electron beam irradiation of Z{sup +}-polar surface in Mg-doped lithium niobate

    SciTech Connect

    Shur, V. Ya. Chezganov, D. S.; Smirnov, M. M.; Alikin, D. O.; Neradovskiy, M. M.; Kuznetsov, D. K.

    2014-08-04

    The appearance of the static domains with depth above 200 μm in the bulk of MgO-doped lithium niobate single crystals as a result of focused electron beam irradiation of Z{sup +}-polar surface was demonstrated. The created domain patterns were visualized by high-resolution methods including piezoresponse force microscopy, scanning electron microscopy, and confocal Raman microscopy. The main stages of the domain structure formation were revealed and explained in terms of the original model.

  5. Effect of electron beam irradiation on bacterial and Ascaris ova loads and volatile organic compounds in municipal sewage sludge

    NASA Astrophysics Data System (ADS)

    Engohang-Ndong, Jean; Uribe, R. M.; Gregory, Roger; Gangoda, Mahinda; Nickelsen, Mike G.; Loar, Philip

    2015-07-01

    Wastewater treatment plants produce large amounts of biosolids that can be utilized for land applications. However, prior to their use, these biosolids must be treated to eliminate risks of infections and to reduce upsetting odors. In this study, microbiological and chemical analyzes were performed before and after treatment of sewage sludge with 3 MeV of an electron beam accelerator in a pilot processing plant. Thus, we determined that dose 4.5 kGy was required to reduce fecal coliform counts to safe levels for land applications of sludge while, 14.5 kGy was necessary to decrease Ascaris ova counts to safe levels. Furthermore, at low doses, electron beam irradiation showed little effect on the concentrations of volatile organic compounds, while some increase were recorded at high doses. The concentration of dimethyl sulfide was reduced by 50-70% at irradiation doses of 25.7 kGy and 30.7 kGy respectively. By contrast, electron beam irradiation increased dimethyl disulfide concentrations. We also showed that electron beam treatment was less energy-consuming with shorter processing times than conventional techniques used to decontaminate sludge. Hence opening new avenues for large urban agglomerations to save money and time when treating biosolids for land application.

  6. Bleaching and micro-cracking phenomena induced in various types of sapphires by keV-electron beam irradiations

    NASA Astrophysics Data System (ADS)

    Lee, Bo-Hyun; Teraji, Tokuyuki; Ito, Toshimichi

    2006-08-01

    Electron-beam-induced phenomena on α-Al 2O 3 single-crystals have been investigated using a scanning electron microscope with a cathodoluminescence (CL) apparatus. Various types of sapphires were irradiated at room temperature by keV electrons of the total fluences up to ≈6 × 10 20 electrons cm -2. In the case of colored specimens, increasing amounts of electron irradiations induced a reversible "bleaching" phenomenon and subsequently an irreversible "cracking" phenomenon on nanometer scales in the surface and subsurface layers. The details of the fluence dependences of these beam-induced changes differed among the various natural and synthetic sapphires. These changes were dramatically reduced by the presence of thin metal layers on the insulating sapphire surfaces, indicating that these phenomena were induced by the presence of charges accumulated in the specimens. Such electron irradiations also varied CL intensities of the F + center peaked at 330 nm while the Cr 3+ center CL peak observed at 697 nm was almost unchanged in intensity with increasing the electron fluence. Furthermore, information on these CL centers along the depth direction from the specimen surface was obtained using variable incident electron energies ranging from 1 to 25 keV. The above phenomena are discussed in relation to the crystalline quality of the specimens examined.

  7. Controlled release of tyrosol and ferulic acid encapsulated in chitosan-gelatin films after electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Benbettaïeb, Nasreddine; Assifaoui, Ali; Karbowiak, Thomas; Debeaufort, Frédéric; Chambin, Odile

    2016-01-01

    This work deals with the study of the release kinetics of antioxidants (ferulic acid and tyrosol) incorporated into chitosan-gelatin edible films after irradiation processes. The aim was to determine the influence of electron beam irradiation (at 60 kGy) on the retention of antioxidants in the film, their release in water (pH=7) at 25 °C, in relation with the barrier and mechanical properties of biopolymer films. The film preparation process coupled to the irradiation induced a loss of about 20% of tyrosol but did not affect the ferulic acid content. However, 27% of the ferulic acid remained entrapped in the biopolymer network during the release experiments whereas all tyrosol was released. Irradiation induced a reduction of the release rate for both compounds, revealing that cross-linking occurred during irradiation. This was confirmed by the mechanical properties enhancement which tensile strength value significantly increased and by the reduction of permeabilities. Although molecular weights, molar volume and molecular radius of the two compounds are very similar, the effective diffusivity of tyrosol was 40 times greater than that of ferulic acid. The much lower effective diffusion coefficient of ferulic acid as determined from the release kinetics was explained by the interactions settled between ferulic acid molecules and the gelatin-chitosan matrix. As expected, the electron beam irradiation allowed modulating the retention and then the release of antioxidants encapsulated.

  8. Synergistic Effects of Electron-beam Irradiation and Leek Extract on the Quality of Pork Jerky during Ambient Storage

    PubMed Central

    Kim, Hyun-Joo; Kang, Mingu; Yong, Hae In; Bae, Young Sik; Jung, Samooel; Jo, Cheorun

    2013-01-01

    To investigate the synergistic effect(s) of electron-beam (EB) irradiation and leek (Allium tuberosum Rottler) extract on the quality of pork jerky during ambient storage, we irradiated prepared pork jerky samples (control and samples with 0.5% and 1.0% leek extract) with EB technology at doses of 0, 1, 2, and 4 kGy, stored them for 2 months at 25°C, and analyzed them. Water activity was 0.73 to 0.77 in non-irradiated samples, and no significant difference in the water activity was observed between the samples treated with leek and the control. The total aerobic bacterial count was significantly decreased with an increase in the irradiation dose and leek extract addition when compared to that of the control (4.54±0.05 log CFU/g). Further, the Hunter color values (L*, a*, and b*) were found to be significantly decreased following leek extract addition and EB irradiation. However, the color values, especially the a* value of the irradiated samples significantly increased during storage. Notably, increasing the EB irradiation dose enhanced the peroxide value. Sensory evaluation revealed that irradiation decreased flavor and overall acceptability. Our findings suggest the use of EB irradiation in combination with leek extract to improve the microbiological safety of pork jerky. However, in order to meet market requirements, novel methods to enhance the sensory quality of pork jerky are warranted. PMID:25049828

  9. Application of Electron-Beam Irradiation Combined with Aging for Improvement of Microbiological and Physicochemical Quality of Beef Loin

    PubMed Central

    Yim, Dong-Gyun; Jo, Cheorun

    2016-01-01

    The combined effects of irradiation and aging temperature on the microbial and chemical quality of beef loin were investigated. The samples were vacuum-packaged, irradiated at 0 or 2 kGy using electron-beam (EB), and stored for 10 d at different aging temperatures (2, 14, or 25℃). The microbial growth, shear values, meat color, and nucleotide-related flavor compounds of the samples were analyzed. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and Escherhia coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose. Irradiation reduced the total aerobic bacteria (TAB) over the storage, but higher aging temperature increased the TBA. Thus TAB increased sharply in non-irradiated and high temperature-aged (14, 25℃) beef samples after 5 d. With increasing aging temperature and aging time, shear force values decreased. Lipid oxidation could be reduced by short aging time at low aging temperature. The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the aging period. As aging period and temperature increased, IMP decreased and hypoxanthine increased. Considering microbial and physicochemical properties, irradiation can be used for raw beef to be aged at relatively high temperature to shorten aging time and cost. PMID:27194930

  10. Enzymatic hydrolysis and characterization of lignocellulosic biomass exposed to electron beam irradiation.

    PubMed

    Karthika, K; Arun, A B; Rekha, P D

    2012-10-01

    Pretreatment of lignocellulosic biomass has been taken up as a global challenge as it comprises a large renewable source of fermentable sugars. In this study, effect of electron beam irradiation (EBI) on a hybrid grass variety investigated as a biomass pretreatment method. Dry biomass samples after characterization were exposed to EBI doses of 0, 75, 150 and 250 kGy. The pretreated biomass samples were enzymatically hydrolyzed using Trichoderma reesei ATCC 26921 cellulase for 144 h. The enzyme loadings were 15 and 30 FPU/g of biomass. The structural changes and degree of crystallinity of the pretreated biomass were studied by FTIR, XRD and SEM analyses. The lignocellulosic biomass sample showed 12.0% extractives, 36.9% cellulose, 28.4% hemicellulose, 11.9% lignin and 8.6% ash. Significant improvements in the reducing sugar and glucose yields were observed in the hydrolysate of EBI pretreated biomass compared to the control. In 250 kGy exposed samples 79% of the final reducing sugar yield was released within 48 h of hydrolysis at an enzyme loading rate of 30FPU/g of biomass. The IR crystallinity index calculated from the FTIR data and degree of crystallinity (XRD) decreased in the EBI treated samples. A significant negative correlation was observed between degree of crystallinity and the glucose yield from enzymatic hydrolysis.

  11. Electric Charge Accumulation in Polar and Non-Polar Polymers under Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

    The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

  12. Electron beam irradiation induced degradation of antidepressant drug fluoxetine in water matrices.

    PubMed

    Shao, Hai-Yang; Wu, Ming-Hong; Deng, Fei; Xu, Gang; Liu, Ning; Li, Xu; Tang, Liang

    2017-10-03

    With the development of psychiatric disorder in the current society, abuse of antidepressant drug fluoxetine (FLX) has made such compound an emerging contaminant in natural waters, and causes endocrine systems disturbance on some aquatic species. Herein, an efficient advanced oxidation process (AOP), electron beam irradiation was carried out to investigate the decomposition characteristics of such novel environmental pollutant, including the effects of initial concentration, pH, radical scavengers and anions. The results showed that FLX degradation followed pseudo-first-order kinetics. The degradation rate and dose constant decreased with increasing initial FLX concentration; and G-values elevated with the increase of initial concentration but reduced with increase of absorbed dose. Acidic condition was more conducive to FLX destruction than neutral and alkaline. The radical scavenger experiments indicated OH was the main reactive species for the decomposition of FLX, while the reductive species e(-)aq and H played an adjuvant role. The presence of anions slightly decreased or even no impact on FLX degradation rate. Various water matrices influenced degradation processes of FLX. Experimental results suggested radiolytic degradation showed the best performance in pure water rather than natural water no matter with filtration or not. Moreover, with the occurrence of defluorination and dealkylation during degradation process, some organic and inorganic intermediates were detected, and the possible degradation mechanisms and pathways of FLX were proposed. Copyright © 2017. Published by Elsevier Ltd.

  13. Characterization of pitch prepared from pyrolysis fuel oil via electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Hong Gun; Park, Mira; Kim, Hak-Yong; Kwac, Lee Ku; Shin, Hye Kyoung

    2017-06-01

    Pitch samples were obtained from pyrolysis fuel oil by thermal treatment for 2 h at 300 °C after electron beam irradiation (EBI) treatment and by thermal treatment alone for different temperature of 250 °C, 300 °C, and 350 °C. EBI treatment was found to be an effective treatment for preparing pitch compare to the pitch obtained without EBI treatment. These results were confirmed by Fourier transform infrared spectroscopy (FT-IR) and Carbon-13 nuclear magnetic resonance (13C NMR) analyses, which showed the increase in the intensities of peaks corresponding to aromatic compounds. In the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectra, the amount of components with medium molecular weights in the pitch was found to increase with the temperature; likewise, in the case of the pitch obtained via EBI treatment, we found that the amount of components with higher molecular weight over 1000 (m/v) similarly increased. Further, the thermal stability and carbon yield at 850 °C of the pitch obtained by EBI were greater than those of samples subjected to thermal treatment at 250 and 300 °C.

  14. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    NASA Astrophysics Data System (ADS)

    Bakar, Khomsaton Abu; Ahmad, Pauzi; Zulkafli, Hashim, Siti A'aisah

    2014-09-01

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD5, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  15. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    SciTech Connect

    Bakar, Khomsaton Abu; Zulkafli,; Hashim, Siti A'aisah; Ahmad, Pauzi

    2014-09-03

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD{sub 5}, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  16. Effect of electron beam irradiation on the microstructure, optical and electrical properties of glass resistive plate chamber detector material

    NASA Astrophysics Data System (ADS)

    Aneeshkumar, K. V.; Krishnaveni, S.; Ranganathaiah, C.; Ravikumar, H. B.

    2017-08-01

    The glass resistive plate chamber (RPC) detector materials were exposed to 8 MeV electron beam from 20 to 100 kGy in steps of 20 kGy. In order to study the electron beam irradiation-induced effects in glass RPC detector material, positron annihilation lifetime spectroscopy (PALS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic investigations were carried out. PALS analysis at lower electron doses indicates the increased void size with the creation of additional sites in the glass network. This is attributed to the breakage of Si-O bonds at the regular tetrahedral sites of Si-O-Si up to 40 kGy. The reduced void size at higher irradiation doses indicates the increased chemical bonding between the tetrahedral sites of Si-O-Si and hence increases the short-range order in the silica glass. These changes are complement with the XRD, FTIR results and the measured electrical conductivity. The variation of AC conductivity with frequency obeys Jonscher power law in all the electron irradiation doses at room temperature. The variation in optical band gap energy from the ultraviolet-visible (UV-Vis) spectra inferred the elimination of defects accumulation at higher irradiation doses due to the glass network close packing.

  17. Physical-, chemical-, and microbiological-based identification of electron beam- and γ-irradiated frozen crushed garlic.

    PubMed

    Kim, Hyo-Young; Ahn, Jae-Jun; Shahbaz, Hafiz Muhammad; Park, Ki-Hwan; Kwon, Joong-Ho

    2014-08-06

    Identification of frozen crushed garlic, commercially available in the Korean market, was performed using four different analytical techniques (three screening and one confirmation). The garlic samples produced in Korea and China were irradiated (electron-beam and γ-rays) at 0, 1, 4, and 7 kGy. Non-irradiated samples showed a relatively moderate population of aerobic bacteria and yeasts/molds around 10(5) CFU/g. Irradiation treatments unequivocally reduced the microbial/fungal populations with dose increments. Microbiological screening through direct epifluorescent filter technique/aerobic plate count (DEFT/APC) method effectively differentiated the non-irradiated and irradiated samples. An electronic nose method positively differentiated the odor patterns of samples based on chemical sensing. However, photostimulated luminescence technique (PSL) exhibited poor sensitivity. Minerals separated from irradiated samples produced thermoluminescence (TL) glow curves in the specific temperature range of 150-250 °C. In conclusion, TL confirmatory analysis gave the most promising results in detecting the irradiation status of garlic samples irrespective of the production origin and type of ionizing radiation treatment.

  18. In situ degradation of antibiotic residues in medical intravenous infusion bottles using high energy electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Min; Zhang, Lele; Zhang, Guilong; Pang, Tao; Zhang, Xin; Cai, Dongqing; Wu, Zhengyan

    2017-01-01

    This study reported an immediate approach for the degradation of three antibiotic (amoxicillin, ofloxacin, and cefradine) residues in medical intravenous infusion bottles (MIIBs) using high energy electron beam (HEEB) irradiation. The effects of irradiation doses, initial concentrations, initial pH, and scavengers of active radicals on the degradation of three antibiotic residues (ARs) were investigated, and the results displayed that 97.02%, 97.61% and 96.87% of amoxicillin, ofloxacin, and cefradine residues could be degraded in situ through HEEB irradiation respectively. Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis demonstrated that ARs were mainly decomposed into inorganic ions and alkanes. Typically, the detailed degradation mechanism of ARs was also investigated, and the dominant active particle inducing the degradation of antibiotics during the HEEB irradiation process was demonstrated to be hydroxyl radical.

  19. In situ degradation of antibiotic residues in medical intravenous infusion bottles using high energy electron beam irradiation

    PubMed Central

    Wang, Min; Zhang, Lele; Zhang, Guilong; Pang, Tao; Zhang, Xin; Cai, Dongqing; Wu, Zhengyan

    2017-01-01

    This study reported an immediate approach for the degradation of three antibiotic (amoxicillin, ofloxacin, and cefradine) residues in medical intravenous infusion bottles (MIIBs) using high energy electron beam (HEEB) irradiation. The effects of irradiation doses, initial concentrations, initial pH, and scavengers of active radicals on the degradation of three antibiotic residues (ARs) were investigated, and the results displayed that 97.02%, 97.61% and 96.87% of amoxicillin, ofloxacin, and cefradine residues could be degraded in situ through HEEB irradiation respectively. Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis demonstrated that ARs were mainly decomposed into inorganic ions and alkanes. Typically, the detailed degradation mechanism of ARs was also investigated, and the dominant active particle inducing the degradation of antibiotics during the HEEB irradiation process was demonstrated to be hydroxyl radical. PMID:28045097

  20. Toxicologic and hygienic investigation of potatoes irradiated with a beam of fast electrons and gamma-rays to control sprouting.

    PubMed

    Zajcev, A N; Shillinger, J I; Kamaldinova, Z M; Osipova, I N

    1975-07-01

    Potatoes exposed either to gamma-rays at a dose of 20 krad, or irradiated with a beam of fast electrons at a dose of 30 krad to inhibit the sprouting of tubers, were studied for mutagenic effects. Toxic action and influence on the fertility were also investigated. Extracts of irradiated potatoes (10 krad gamma-rays), stored and then boiled, were also studied for their mutagenic effects. The induction of dominant lethal mutations (DLM) was used as indicator of mutagenic action of potatoes in male rats, that of the extracts of potatoes in male mice. Experimental animals (white rats) were fed with irradiated potatoes. Neither a toxic, nor a mutagenic action was found. Oral treatment of male mice with extracts of irradiated potatoes also did not increase the frequency of DLM in male mice.

  1. Effects of Electron Beam Irradiation on Zearalenone and Ochratoxin A in Naturally Contaminated Corn and Corn Quality Parameters

    PubMed Central

    Luo, Xiaohu; Qi, Lijun; Liu, Yuntao; Wang, Ren; Yang, Dan; Li, Ke; Wang, Li; Li, Yanan; Zhang, Yuwei; Chen, Zhengxing

    2017-01-01

    Zearalenone (ZEN) and ochratoxin A (OTA) are secondary toxic metabolites widely present in grains and grain products. In this study, the effects of electron beam irradiation (EBI) on ZEN and OTA in corn and the quality of irradiated corn were investigated. Results indicated that EBI significantly affected ZEN and OTA. The degradation rates of ZEN and OTA at 10 kGy in solution were 65.6% and 75.2%, respectively. The initial amounts significantly affected the degradation rate. ZEN and OTA in corn were decreased by the irradiation dose, and their degradation rates at 50 kGy were 71.1% and 67.9%, respectively. ZEN and OTA were more easily degraded in corn kernel than in corn flour. Moisture content (MC) played a vital role in ZEN and OTA degradation. High MC was attributed to high ZEN and OTA degradation. The quality of irradiated corn was evaluated on the basis of irradiation dose. L* value changed, but this change was not significant (p > 0.05). By contrast, a* and b* decreased significantly (p < 0.05) with irradiation dose. The fatty acid value increased significantly. The pasting properties, including peak, trough, breakdown, and final and setback viscosities, were also reduced significantly (p < 0.05) by irradiation. Our study verified that EBI could effectively degrade ZEN and OTA in corn. Irradiation could also affect corn quality. PMID:28264463

  2. Protein carbonylation during electron beam irradiation may be responsible for changes in IgE binding to turbot parvalbumin.

    PubMed

    Li, Zhenxing; Lu, Zongchao; Khan, Muhammad Naseem; Lin, Hong; Zhang, Limin

    2014-07-01

    The present study aimed to investigate the relationship between protein carbonylation and changes of the IgE reactivity of turbot parvalbumin (PV) following electron beam (EB) irradiation. The concentration of protein carbonyls, specific IgE binding, and IgE binding inhibition between irradiated and oxidized PV were assessed. Irradiation resulted in a 3-fold enhancement in the protein carbonyl content. In purified PV irradiated with a 10-kGy dose, specific IgE binding was reduced by 91.2±6.2%. When raw PV was treated with reactive oxygen species (ROS), the protein carbonyl content increased 17.6-fold, with the specific IgE binding being reduced by 87.9±6.5% at an ROS concentration of 10 nmol/mL. The IgE binding inhibition between irradiated and oxidized PV was investigated using an inhibition ELISA. Results showed that oxidized PV can inhibit the binding between irradiated PV and specific IgE with an IC50 of 8.2-58 ng according to different doses of irradiation. These findings suggest that EB irradiation reduces specific IgE binding, probably by the induction of protein carbonylation.

  3. Dosimetric study of total skin irradiation with a scanning beam electron accelerator.

    PubMed

    Sharma, S C; Wilson, D L

    1987-01-01

    The Therac 20 6-MeV scanned electron beam may be used for partial or total skin therapy. The maximum field size at 1 m is 30 X 30 cm defined by a set of primary photon collimators in conjunction with secondary trimmers. We have studied electron beam profiles with and without trimmers at the nominal source-skin distance of 1 m versus extended distances of 3-5 m. We find that the trimmers limit the field size and add little to the beam uniformity at extended distances. Beam energy, dose distributions, and output factors at extended distances were measured for single and multiple field arrangements with and without trimmers. Beam parameters were measured after introducing a degrader that lowered the energy to 3.7 MeV.

  4. Dosimetric study of total skin irradiation with a scanning beam electron accelerator

    SciTech Connect

    Sharma, S.C.; Wilson, D.L.

    1987-05-01

    The Therac 20 6-MeV scanned electron beam may be used for partial or total skin therapy. The maximum field size at 1 m is 30 x 30 cm defined by a set of primary photon collimators in conjunction with secondary trimmers. We have studied electron beam profiles with and without trimmers at the nominal source--skin distance of 1 m versus extended distances of 3--5 m. We find that the trimmers limit the field size and add little to the beam uniformity at extended distances. Beam energy, dose distributions, and output factors at extended distances were measured for single and multiple field arrangements with and without trimmers. Beam parameters were measured after introducing a degrader that lowered the energy to 3.7 MeV.

  5. Extraction, identification, and quantification of flavonoids and phenolic acids in electron beam-irradiated almond skin powder.

    PubMed

    Teets, A S; Minardi, C S; Sundararaman, M; Hughey, C A; Were, L M

    2009-04-01

    The effect of electron beam irradiation doses from 0 to 30 kGy on extraction yield and phenolic compounds was evaluated in almond skin phenolic extracts (ASPE). Total soluble phenols and distribution of phenolic compounds from acidified methanol ASPE and 52% methanol ASPE were quantified using Folin-Ciocalteau method, liquid chromatography with diode array and fluorescence detection, and negative ion electrospray-mass spectrometry. Electron beam irradiation increased extraction yield by as much as 23%, with the greatest increase observed in the acidified methanol ASPE. Irradiated samples extracted with acidified methanol also exhibited an increase in extractable phenols (Folin-Ciocalteau) and total HPLC-resolved phenolics at all irradiation doses. Samples extracted with 52% methanol exhibited an increase at 10 and 20 kGy, but a 31% decrease at 30 kGy. An increase in aglycones respective to their glycosides was not observed with irradiation. Therefore, the increase in phenolics was attributed to release of phenolics from their cellular matrix.

  6. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-06-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens ( Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  7. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Borisyuk, P. V.; Vasilyev, O. S.; Lebedinskii, Y. Y.; Krasavin, A. V.; Tkalya, E. V.; Troyan, V. I.; Habibulina, R. F.; Chubunova, E. V.; Yakovlev, V. P.

    2016-09-01

    In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  8. Improving the Mechanical Performance and Thermal Stability of a PVA-Clay Nanocomposite by Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Shokuhi Rad, A.; Ebrahimi, D.

    2017-07-01

    The effects of electron beam irradiation and presence of clay on the mechanical properties and thermal stability of montmorillonite clay-modified polyvinyl alcohol nanocomposites were studied. By using the X-ray diffraction (XRD) and transmission electron microscopy (TEM), the microstructure of the nanocomposites was investigated. The results obtained from TEM and XRD tests showed that montmorillonite clay nanoparticles were located in the polyvinyl alcohol phase. The XRD analysis confirmed the formation of an exfoliated structure in nanocomposites samples. Increasing the amount of clay to 20 wt.% increased the tensile strength and modulus of the nanocomposite. Irradiation up to an absorbed dose of 100 kGy increased its mechanical properties and thermal stability, but at higher irradiation levels, the mechanical strength and thermal stability declined. The sample with 20 wt.% of the nanofiller, exposed to 100 kGy, showed the highest mechanical strength and thermal stability.

  9. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    NASA Astrophysics Data System (ADS)

    Chong, E. L.; Ahmad, Ishak; Dahlan, H. M.; Abdullah, Ibrahim

    2010-08-01

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m 2, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  10. Theory of the fracture of solid bodies by irradiation with intense pulsed electron beams

    NASA Astrophysics Data System (ADS)

    Borzykh, A. A.; Cherepanov, G. P.

    1980-12-01

    The beam-induced fracture phenomenon consists of the formation of electron bunches in the solid body which act as 'knives' or 'wedges' cutting the body. The basic model problems of the pulsed electron fracture of solid materials are reviewed. Attention is given to the collective relativistic interaction of electron beams with materials; a mechanism of self-densification of electron beams is discussed. An exact solution is obtained for the plane stationary dynamic problem of elasticity for the supersonic motion of an infinite thin wedge. This solution is used to study the deceleration of a finite wedge in the quasi-steady approximation; a simple evaluation of the dimensions of fracture is obtained for large initial velocity of the wedge.

  11. Reduction of Salmonella enterica serotype Poona and background microbiota on fresh-cut cantaloupe by electron beam irradiation.

    PubMed

    Palekar, Mangesh P; Taylor, T Matthew; Maxim, Joseph E; Castillo, Alejandro

    2015-06-02

    The efficacy of electron beam (e-beam) irradiation processing to reduce Salmonella enterica serotype Poona on surfaces of fresh-cut cantaloupe, and the impact of e-beam irradiation processing on the numbers of indigenous microorganisms were determined. Additionally, the D10-value for S. Poona reduction on the cut cantaloupe was also determined. Fresh-cut cantaloupe pieces, inoculated with S. Poona to 7.8 log10 CFU/g, were exposed to 0.0, 0.7, or 1.5 kGy. Surviving S. Poona, lactic acid bacteria (LAB), and fungi (yeasts, molds) were periodically enumerated on appropriate media over 21 days of storage at 5 °C. Cantaloupe surface pH was measured for irradiated cantaloupe across the 21 day storage period. To determine the D10-value of S. Poona, cantaloupe discs were inoculated and exposed to increasing radiation dosages between 0 and 1.06 kGy; surviving pathogen cells were selectively enumerated. S. Poona was significantly reduced by irradiation; immediate reductions following exposure to 0.7 and 1.5 kGy were 1.1 and 3.6 log10 CFU/g, respectively. After 21 days, S. Poona numbers were between 4.0 and 5.0 log10 CFU/g less than untreated samples at zero-time. Yeasts were not reduced significantly (p ≥ 0.05) by e-beam irradiation and grew slowly but steadily during storage. Counts of LAB and molds were initially reduced with 1.5 kGy (p<0.05) but then LAB recovered grew to high numbers, whereas molds slowly declined for irradiated and control samples. Cantaloupe pH declined during storage, with the greatest decrease in untreated control cantaloupe (p<0.05). The D10-value for S. Poona was determined to be 0.211 kGy, and this difference from the reductions observed in the cut cantaloupe studies may be due to the more precise dose distribution obtained in the thin and flat cantaloupe pieces used for the D10-value experiments. The effect of e-beam irradiation at the same doses used in this study was determined in previous studies to have no negative effect in the quality of

  12. Photoluminescence from 20 MeV electron beam irradiated homogeneous SiOx and composite Si-SiOx films

    NASA Astrophysics Data System (ADS)

    Nesheva, D.; Šćepanović, M.; Grujić-Brojčin, M.; Dzhurkov, V.; Kaschieva, S.; Bineva, I.; Dmitriev, S. N.; Popović, Z. V.

    2016-10-01

    The effect of 20 MeV electron irradiation on the room temperature photoluminescence from homogeneous SiOx and composite Si-SiOx films, containing amorphous or crystalline Si nanoparticles, is studied. Layers with x = 1.5 and 1.7 and thickness of 200 nm were deposited on crystalline silicon substrates by thermal evaporation of SiO in vacuum. Film annealing in an inert atmosphere at 700 oC or 1000 oC for 60 min was applied to grow amorphous or crystalline silicon nanoparticles, respectively, in a SiOx matrix. Samples from all types of films were irradiated with 20 MeV electrons at close to room temperature and a fluence of 2.4x1014 el.cm-2. Photoluminescence was measured under excitation with the 488 nm line of an Ar+ laser. The electron irradiation causes a decrease of the integrated photoluminescence intensity in composite samples with initial x = 1.7 containing amorphous or crystalline nanoparticles and x = 1.5 samples with Si nanocrystals. The electron irradiation of x = 1.5 samples with amorphous nanoparticles slightly increases the photoluminescence intensity. The obtained results are discussed in terms of electron beam induced phase separation and Si nanoparticle size increase.

  13. Combined total body X-ray irradiation and total skin electron beam radiotherapy with an improved technique for mycosis fungoides

    SciTech Connect

    Halberg, F.E.; Fu, K.K.; Weaver, K.A.; Zackheim, H.S.; Epstein, E.H. Jr.; Wintroub, B.U.

    1989-08-01

    Twelve consecutive patients with advanced stage mycosis fungoides (MF) were treated with combined total body X ray irradiation (TBI) and total skin electron beam radiotherapy (EBRT). Six had generalized plaque disease and dermatopathic nodes, three had tumor stage disease and node biopsy positive for mycosis fungoides, and three had erythroderma/Sezary syndrome. The treatment regimen consisted of split course total body X ray irradiation, given in twice weekly 15 cGy fractions to 75 cGy, then total skin electron beam radiation therapy given in once weekly 400 cGy fractions to a total dose of 2400 cGy. Underdosed areas and areas of greatest initial involvement were boosted 400 cGy twice weekly for an additional 1200 cGy. This was followed by a second course of total body X ray irradiation, to a total dose of 150 cGy. The total skin electron beam radiotherapy technique is a modification of an established six position EBRT technique for mycosis fungoides. Measurements to characterize the beam with and without a lexan scattering plate, demonstrated that the combination of no-plate beams produced better dose uniformity with a much higher dose rate. This improved technique is particularly advantageous for elderly and/or frail patients. Nine (75%) of the 12 patients achieved complete response (CR). The other three had significant improvement with greater than 80% clearing of their disease and resolution of symptoms. All six patients with generalized plaque disease achieved complete response and remained free of disease from 2 to 16 months. Two of three node positive patients also achieved complete response; one, with massive biopsy-documented mycosis fungoides nodal disease and deep open tumors, remained relapse-free over 2 years. Only one of the three patients with erythroderma/Sezary syndrome achieved a complete response, which was short lived.

  14. Improved dose homogeneity in scalp irradiation using a single set-up point and different energy electron beams.

    PubMed

    Yaparpalvi, R; Fontenla, D P; Beitler, J J

    2002-08-01

    Homogeneous irradiation of the entire or a large portion of the superficial scalp poses both technical and dosimetric challenges. Some techniques will irradiate too much of the underlying normal brain while other techniques are either complex and involve field matching problems or may require sophisticated linear accelerator (linac) add-ons such as intensity modulated radiation therapy (IMRT)/electron multileaf collimation. However, many radiotherapy facilities are not equipped with such treatment modalities. We propose a practical treatment technique that can be delivered with a standard linac capable of producing high energy electrons. The proposed technique offers a simple alternative for achieving results equivalent to IMRT. Dose homogeneity throughout the treatment volume is achieved by aiming different energy electron beams at differential areas of the treatment surface to achieve improved dosimetry and rapid treatment delivery, while using a single set-up point. We introduced this treatment technique at our institution to treat superficial cancers of the scalp and other irregular surfaces.

  15. Low energy electron beam irradiation effect on optical properties of nanopillar MQW InGaN/GaN structures

    SciTech Connect

    Yakimov, E. B.; Vergeles, P. S.; Polyakov, A. Y.; Jeon, Dae-Woo; Lee, In-Hwan

    2014-02-21

    The low energy electron beam irradiation (LEEBI) effect on optical properties of planar and nanopillar InGaN/GaN muliple quantum well light emitting structures was studied by the cathodoluminescence (CL) method. On the planar structures LEEBI leads to a formation of new InGaN-related emission bands red shifted in comparison with initial one at small irradiation doses and blue shifted at doses higher than 0.5 C/cm{sup 2}. It was observed that after dry etching used for the nanopillar formation the main InGaN-related emission line moves from 2.92 to 2.98 eV that can be explained by a strain relaxation in the quantum wells. The optical properties of nanopilars start to change under LEEBI at a dose of about one order of magnitude lower than that for planar structures. At high irradiation doses the behavior of both structures under LEEBI is similar. The results obtained were explained by the formation and reconstruction of quantum dots inside the quantum wells due to a point defect generation and redistribution stimulated by the electron beam irradiation.

  16. Reversible wettability of electron-beam deposited indium-tin-oxide driven by ns-UV irradiation

    SciTech Connect

    Persano, Luana; Del Carro, Pompilio; Pisignano, Dario

    2012-04-09

    Indium tin oxide (ITO) is one of the most widely used semiconductor oxides in the field of organic optoelectronics, especially for the realization of anode contacts. Here the authors report on the control of the wettability properties of ITO films deposited by reactive electron beam deposition and irradiated by means of nanosecond-pulsed UV irradiation. The enhancement of the surface water wettability, with a reduction of the water contact angle larger than 50 deg., is achieved by few tens of seconds of irradiation. The analyzed photo-induced wettability change is fully reversible in agreement with a surface-defect model, and it can be exploited to realize optically transparent, conductive surfaces with controllable wetting properties for sensors and microfluidic circuits.

  17. Volatile compounds and odor traits of dry-cured ham (Prosciutto crudo) irradiated by electron beam and gamma rays

    NASA Astrophysics Data System (ADS)

    Kong, Qiulian; Yan, Weiqiang; Yue, Ling; Chen, Zhijun; Wang, Haihong; Qi, Wenyuan; He, Xiaohua

    2017-01-01

    Prosciutto crudo samples were irradiated at 0, 3 and 6 kGy by gamma rays (GR) and electron beam (EB), respectively. The odor scores and volatile compounds were examined after 7 days storage at 4 °C. Volatile compounds from samples without and with irradiation at 6 kGy were analyzed by GC-MS. Fifty-nine compounds were identified, including terpenes, aldehydes, alcohols, ketones, alkanes, esters, aromatic hydrocarbons and acids. Both GR and EB irradiation resulted in formation of (Z)-7-Hexadecenal, cis-9-hexadecenal, tetradecane, E-9-tetradecen-1-ol formate, and losing of hexadecamethyl-heptasiloxane and decanoic acid-ethyl ester in hams. However, GR irradiation caused additional changes, such as formation of undecane and phthalic acid-2-cyclohexylethyl butyl ester, significantly higher level of 1-pentadecene, and losing of (E, E)-2,4-decadienal and octadecane. EB was shown to be better in maintaining ham's original odor than GR. Our results suggest that EB irradiation is a promising method for treatment of ready to eat hams as it exerts much less negative effect on the flavor of hams compared to GR irradiation.

  18. Irradiation Effect of keV Region Electron Beam on Bleaching and Cracking of Various Types of Sapphires

    NASA Astrophysics Data System (ADS)

    Lee, Bo-Hyun; Teraji, Tokuyuki; Ito, Toshimichi

    Various types of single-crystalline α-Al2O3 have been investigated on bleaching and cracking effects of keV electron beams using scanning electron microscope (SEM) and cathodoluminescence (CL) measurements. These electron-irradiation-induced effects observed at room temperature were different among four types of sapphires examined, namely, Be-diffusion-treated natural, untreated natural, synthetic orange, and synthetic red sapphires. The bleaching phenomenon occurred at electron dosages and the surface cracking phenomenon was subsequently observed at substantially higher dosages. The former was reversible so that an appropriate annealing in an oxygen atmosphere completely removed the bleached areas whereas the latter was a permanent change in structure that was not able to be recovered at all by such a treatment. It is found from these evidences that the crystalline quality of each specimen was well correlated with its beam-dose dependences of the electron-beam-induced phenomena observed. It should be noted that such electron-induced effects were almost completely reduced by the presence of a thin conductive layer on the insulating specimen surfaces.

  19. Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

    SciTech Connect

    Zhu, Xianfang Li, Lunxiong; Gong, Huimin; Yang, Lan; Sun, Chenghua

    2014-09-01

    Electron beam-induced nanoinstabilities of pristine double-walled carbon nanotubes (DWCNTs) of two different configurations, one fixed at both ends and another fixed at only one end, were in-situ investigated in transmission electron microscope at room temperature. It was observed that the DWCNT fixed at both ends shrank in its diameter uniformly. Meanwhile, the DWCNT fixed at only one end intriguingly shrank preferentially from its free cap end along its axial direction whereas its diameter shrinkage was offset. A mechanism of “diffusion” along with “evaporation” at room temperature which is driven by the nanocurvature of the DWCNTs, and the athermal activation induced by the electron beam was proposed to elucidate the observed phenomena. The effect of the interlayer interaction of the DWCNTs was also discussed.

  20. Influence of electron beam irradiation on spectral, thermal, morphological and catalytic properties of Co(II) complex immobilized on chitosan's Schiff base.

    PubMed

    Antony, R; Theodore David, S; Karuppasamy, K; Sanjeev, Ganesh; Balakumar, S

    2014-04-24

    This study was carried out to investigate the effect of electron beam irradiation on the spectral and catalytic properties of chitosan supported (ONClCl) tetra coordinated Co(II) complex, [Co(OIAC)Cl2]. The complex was subjected to electron beam irradiation of 100 Gy, 1 kGy and 10 kGy doses. Chain scission of chitosan was observed on irradiation at 100 Gy and 10 kGy and chain linking at 1 kGy as evidenced by viscosity and FT-IR spectroscopic studies. This observation was also confirmed by thermo gravimetric and differential thermogravimetric (TG-DTG) analysis. It revealed that the thermal stability of the complex was increased at 1 kGy irradiation and decreased at 100 Gy and 10 kGy. In addition, the effect of electron beam irradiation on the surface morphology of the complex was studied by scanning electron microscopy. Catalytic abilities of both non-irradiated complex and irradiated complexes were determined and compared in the cyclohexane oxidation using hydrogen peroxide oxidant. The catalytic activity was found to increase after irradiation at all doses. Though the complex irradiated at 10 kGy showed highest conversion efficiency, irradiation at 1 kGy is suggested as the best dose due to the extensive reusability and adequate catalytic ability of the complex.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Optical and chemical behaviors of CR-39 and Makrofol plastics under low-energy electron beam irradiation

    NASA Astrophysics Data System (ADS)

    El-Saftawy, Ashraf Ali; Abd El Aal, Saad Ahmed; Hassan, Nabil Mohamed; Abdelrahman, Moustafa Mohamed

    2016-07-01

    In this study, CR-39 and Makrofol plastic nuclear track detectors were irradiated with low-energy electron beams to study the effect of the induced changes on their optical and chemical properties. Surface chemical changes were recorded by Fourier transform infrared (FTIR) spectroscopy, which showed successive degradation and crosslinking for CR-39 and decomposition for Makrofol. The optical band gap was determined by UV-vis spectroscopy. Also, the parameters of carbon cluster formation and disordering (Urbach’s energy) occurring on plastic surfaces were examined. The intrinsic viscosity changes were investigated as well. As a result, low-energy electron beams were found to be useful for the control of many properties of the surfaces of the investigated detectors.

  3. Analysis of organic acids in electron beam irradiated chestnuts (Castanea sativa Mill.): Effects of radiation dose and storage time.

    PubMed

    Carocho, Márcio; Barros, Lillian; Antonio, Amilcar L; Barreira, João C M; Bento, Albino; Kaluska, Iwona; Ferreira, Isabel C F R

    2013-05-01

    Since 2010, methyl bromide, a widely used fumigant was banned from the European Union under the Montreal Protocol guidelines, due to its deleterious effects on health and risk to the environment. Since then, many alternatives for chestnut conservation have been studied (hot water dip treatment being the most common), among them, electron beam irradiation has been proposed as being a safe, clean and cheap alternative. Herein, the effects of this radiation at different doses up to 6kGy and over storage up to 60days in the amounts and profile of nutritionally important organic acids were evaluated. Chestnuts contained important organic acids with quinic and citric acids as main compounds. Storage time, which is traditionally well accepted by consumers, caused a slight decrease on quinic (13-9mg/g), ascorbic (1.2-0.8mg/g), malic (5-4mg/g), fumaric (0.4-0.3mg/g) and total organic (33-26mg/g) acids content. Otherwise, irradiation dose did not cause appreciable changes, either individually or in total (28-27mg/g) organic acid contents. Electron beam irradiation might constitute a valuable alternative for chestnut conservation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Effect of dose rate on inactivation of microorganisms in spices by electron-beams and gamma-rays irradiation

    NASA Astrophysics Data System (ADS)

    Ito, Hitoshi; Islam, Md. Shamsul

    1994-06-01

    Total aerobic bacteria in spices used in this study were determined to be 1 × 10 6 to 6 × 10 7 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9kGy of EB (electron-beams) or γ-irradiation were required to reduce the total aerobic bacteria in many However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These difference of radiation sensitivities between EB and γ-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. However, components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and γ-rays.

  5. Effect of an electron beam irradiation on optical and luminescence properties of LiBaAlF6 single crystals

    NASA Astrophysics Data System (ADS)

    Ogorodnikov, I. N.; Pustovarov, V. A.; Omelkov, S. I.; Kirm, M.

    2017-07-01

    Paper reports the effect of a 10 keV, 110 keV and 10 MeV electron beam irradiation on optical and luminescence properties of LiBaAlF6 (LBAF) single crystals at 10, 90, and 293 K. Five absorption bands at 2.0, 3.2, 4.3, 4.9 and 5.5 eV were revealed in irradiated crystals in the energy range of 1.2-9.5 eV. Several PL emission bands (1.7-1.8, 2.2 and 2.5-3.5 eV) related to defects were found in the luminescence spectra at room temperature, while only one luminescence band at E = 2.2 eV appears at T = 90 K in LBAF crystals after a 10 MeV electron bombardment. The PL excitation spectra and time-response for these emission bands were studied at 10, 90, and 293 K. Thermoluminescence (TL) of irradiated crystals was studied in the temperature range of 90-740 K. New TL glow peaks at 166, 530 and 670 K were revealed and their parameters were determined. Temperature dependence of relative photoluminescence yield recorded monitoring emission at the 1.87 and 2.23 eV in the temperature range from 130 to 450 K, were fitted using five quenching processes related to TL glow peaks revealed in our research. Significant similarity in the manifestation of radiation-induced defects for LBAF and previously studied LiBaF3 single crystals is noted. The effect of an electron beam irradiation on optical and luminescence properties of LBAF single crystals and possible origin of the radiation defects were discussed.

  6. Selective surface purification via crater eruption under pulsed electron beam irradiation

    SciTech Connect

    Zou Jianxin; Zhang Kemin; Dong Chuang; Qin Ying; Hao Shengzhi; Grosdidier, Thierry

    2006-07-24

    This letter reports an interesting phenomenon associated with the high-current pulsed electron beam treatment:selective surface purification. The treatment induces crater eruptions that preferentially occur at irregular composition and structure sites. The eruptions of second phase inclusions naturally lead to the purification and homogenization of the melted surface layer. This improves significantly the corrosion resistance of NiTi and 316L alloys.

  7. Experimental validation of a numerical model predicting the charging characteristics of Teflon and Kapton under electron beam irradiation

    NASA Technical Reports Server (NTRS)

    Hazelton, R. C.; Yadlowsky, E. J.; Churchill, R. J.; Parker, L. W.; Sellers, B.

    1981-01-01

    The effect differential charging of spacecraft thermal control surfaces is assessed by studying the dynamics of the charging process. A program to experimentally validate a computer model of the charging process was established. Time resolved measurements of the surface potential were obtained for samples of Kapton and Teflon irradiated with a monoenergetic electron beam. Results indicate that the computer model and experimental measurements agree well and that for Teflon, secondary emission is the governing factor. Experimental data indicate that bulk conductivities play a significant role in the charging of Kapton.

  8. Experimental validation of a numerical model predicting the charging characteristics of Teflon and Kapton under electron beam irradiation

    NASA Technical Reports Server (NTRS)

    Hazelton, R. C.; Yadlowsky, E. J.; Churchill, R. J.; Parker, L. W.; Sellers, B.

    1981-01-01

    The effect differential charging of spacecraft thermal control surfaces is assessed by studying the dynamics of the charging process. A program to experimentally validate a computer model of the charging process was established. Time resolved measurements of the surface potential were obtained for samples of Kapton and Teflon irradiated with a monoenergetic electron beam. Results indicate that the computer model and experimental measurements agree well and that for Teflon, secondary emission is the governing factor. Experimental data indicate that bulk conductivities play a significant role in the charging of Kapton.

  9. Transformation dynamics of Ni clusters into NiO rings under electron beam irradiation.

    PubMed

    Knez, Daniel; Thaler, Philipp; Volk, Alexander; Kothleitner, Gerald; Ernst, Wolfgang E; Hofer, Ferdinand

    2017-05-01

    We report the transformation of nickel clusters into NiO rings by an electron beam induced nanoscale Kirkendall effect. High-purity nickel clusters consisting of a few thousand atoms have been used as precursors and were synthesized with the superfluid helium droplet technique. Aberration-corrected, analytical scanning transmission electron microscopy was applied to oxidise and simultaneously analyse the nanostructures. The transient dynamics of the oxidation could be documented by time lapse series using high-angle annular dark-field imaging and electron energy-loss spectroscopy. A two-step Cabrera-Mott oxidation mechanism was identified. It was found that water adsorbed adjacent to the clusters acts as oxygen source for the electron beam induced oxidation. The size-dependent oxidation rate was estimated by quantitative EELS measurements combined with molecular dynamics simulations. Our findings could serve to better control sample changes during examination in an electron microscope, and might provide a methodology to generate other metal oxide nanostructures. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Transformation dynamics of Ni clusters into NiO rings under electron beam irradiation.

    PubMed

    Knez, Daniel; Thaler, Philipp; Volk, Alexander; Kothleitner, Gerald; Ernst, Wolfgang E; Hofer, Ferdinand

    2016-12-13

    We report the transformation of nickel clusters into NiO rings by an electron beam induced nanoscale Kirkendall effect. High-purity nickel clusters consisting of a few thousand atoms have been used as precursors and were synthesized with the superfluid helium droplet technique. Aberration-corrected, analytical scanning transmission electron microscopy was applied to oxidise and simultaneously analyse the nanostructures. The transient dynamics of the oxidation could be documented by time lapse series using high-angle annular dark-field imaging and electron energy-loss spectroscopy. A two-step Cabrera-Mott oxidation mechanism was identified. It was found that water adsorbed adjacent to the clusters acts as oxygen source for the electron beam induced oxidation. The size-dependent oxidation rate was estimated by quantitative EELS measurements combined with molecular dynamics simulations. Our findings could serve to better control sample changes during examination in an electron microscope, and might provide a methodology to generate other metal oxide nanostructures. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. New Elastomeric Materials Based on Natural Rubber Obtained by Electron Beam Irradiation for Food and Pharmaceutical Use

    PubMed Central

    Craciun, Gabriela; Manaila, Elena; Stelescu, Maria Daniela

    2016-01-01

    The efficiency of polyfunctional monomers as cross-linking co-agents on the chemical properties of natural rubber vulcanized by electron beam irradiation was studied. The following polyfunctional monomers were used: trimethylolpropane-trimethacrylate, zinc-diacrylate, ethylene glycol dimethacrylate, triallylcyanurate and triallylisocyanurate. The electron beam treatment was done using irradiation doses in the range of 75 kGy–300 kGy. The gel fraction, crosslink density and effects of different aqueous solutions, by absorption tests, have been investigated as a function of polyfunctional monomers type and absorbed dose. The samples gel fraction and crosslink density were determined on the basis of equilibrium solvent-swelling measurements by applying the modified Flory–Rehner equation for tetra functional networks. The absorption tests were done in accordance with the SR ISI 1817:2015 using distilled water, acetic acid (10%), sodium hydroxide (1%), ethylic alcohol (96%), physiological serum (sodium chloride 0.9%) and glucose (glucose monohydrate 10%). The samples structure and morphology were investigated by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy techniques. PMID:28774150

  12. Insights from investigations of tin dioxide and its composites: electron-beam irradiation, fractal assessment, and mechanism

    NASA Astrophysics Data System (ADS)

    Chen, Zhiwen; Shek, Chan-Hung; Lawrence Wu, C. M.

    2015-09-01

    Tin dioxide (SnO2) is a unique strategic functional material with widespread technological applications, particularly in fields such as solar batteries, optoelectronic devices, and solid-state gas sensors owing to advances in its optical and electronic properties. In this review, we introduce the recent progress of tin dioxide and its composites, including the synthesis strategies, microstructural evolution, related formation mechanism, and performance evaluation of SnO2 quantum dots (QDs), thin films, and composites prepared by electron-beam irradiation, pulsed laser ablation, and SnO2 planted graphene strategies, highlighting contributions from our laboratory. First, we present the electron-beam irradiation strategies for the growth behavior of SnO2 nanocrystals. This method is a potentially powerful technique to achieve the nucleation and growth of SnO2 QDs. In addition, the fractal assessment strategies and gas sensing behavior of SnO2 thin films with interesting micro/nanostructures induced by pulsed delivery will be discussed experimentally and theoretically. Finally, we emphasize the fabrication process and formation mechanism of SnO2 QD planted graphene nanosheets. This review may provide a new insight that the versatile strategies for microstructural evolution and related performance of SnO2-based functional materials are of fundamental importance in the development of new materials.

  13. Photocurrent generation in lateral graphene p-n junction created by electron-beam irradiation

    PubMed Central

    Yu, Xuechao; Shen, Youde; Liu, Tao; Wu, Tao (Tom); Jie Wang, Qi

    2015-01-01

    Graphene has been considered as an attractive material for optoelectronic applications such as photodetectors owing to its extraordinary properties, e.g. broadband absorption and ultrahigh mobility. However, challenges still remain in fundamental and practical aspects of the conventional graphene photodetectors which normally rely on the photoconductive mode of operation which has the drawback of e.g. high dark current. Here, we demonstrated the photovoltaic mode operation in graphene p-n junctions fabricated by a simple but effective electron irradiation method that induces n-type doping in intrinsic p-type graphene. The physical mechanism of the junction formation is owing to the substrate gating effect caused by electron irradiation. Photoresponse was obtained for this type of photodetector because the photoexcited electron-hole pairs can be separated in the graphene p-n junction by the built-in potential. The fabricated graphene p-n junction photodetectors exhibit a high detectivity up to ~3 × 1010 Jones (cm Hz1/2 W−1) at room temperature, which is on a par with that of the traditional III–V photodetectors. The demonstrated novel and simple scheme for obtaining graphene p-n junctions can be used for other optoelectronic devices such as solar cells and be applied to other two dimensional materials based devices. PMID:26152225

  14. Comparison of the changes of the antigenicities of a hen's egg albumin by a gamma and an electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Seo, Ji-Hyun; Kim, Jae-Hun; Lee, Soo-Young; Byun, Myung-Woo

    2007-05-01

    The study was conducted to compare the radiation types of a gamma ray and an electron beam for the inhibition and reduction of a food allergy. OVA (2 mg/ml) were irradiated at 3, 5, 7 and 10 kGy. Patterns detected by the SDS-PAGE and an immunoblot showed that the intact OVA band disappeared and that it was dependant upon the radiation doses regardless of the radiation types. Binding abilities of the irradiated OVA against the monoclonal IgG and the egg allergic patients' IgE decreased due to a conformational change of the epitope, but differences from using the two different radiation types were not observed. The results indicate that both the radiation types can be used for an inhibition and a reduction of a food allergy regardless of the radiation types.

  15. Formation of uniformly sized gold nanoparticles over graphene by MeV electron beam irradiation for transparent conducting films

    SciTech Connect

    Kim, Yooseok; Lee, Su-il; Youb Lee, Seung; Cha, Myoung-Jun; Song, Wooseok; Sung Jung, Dae; Park, Chong-Yun

    2013-06-03

    Highly flexible, transparent, and conducting sheet was fabricated by decoration of uniformly sized gold nanoparticles (Au NPs) with high-density on large-area graphene by MeV electron beam irradiation (MEBI) at room temperature under ambient conditions. The Au NPs with an average size of 13.6 ± 3.5 nm were clearly decorated on the graphene after MEBI with an irradiation energy of 1.0 MeV. The sheet resistances of the Au NPs/graphene significantly decreased. For the Au NPs/trilayer graphene, the sheet resistance reached to ∼45 Ω/sq, and the optical transmittance was ∼90.2% which is comparable to that of conventional indium tin oxide film.

  16. Synthesis and swelling characteristics of poly (N-isopropylacrylamide) temperature sensitive hydrogels crosslinked by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Panda, Anjali; Manohar, S. B.; Sabharwal, S.; Bhardwaj, Y. K.; Majali, A. B.

    2000-03-01

    Temperature sensitive fast response poly (N-isopropylacrylamide) (PNIPAAm) hydrogels have been synthesized by simultaneously polymerizing and crosslinking NIPAAm monomer in aqueous solutions by electron beam (EB) and gamma irradiation and their equilibrium and dynamic swelling behavior have been investigated. The weight change kinetic studies show that radiation crosslinked hydrogels swell/deswell to attain equilibrium at much faster rate with diffusion coefficient values D≈4.0×10 -7 cm 2s -1 and 15×10 -5 cm 2s -1 for swelling and deswelling respectively. The effect of radiation characteristics such as irradiation dose, dose rate on the lower critical solution temperature (LCST), gelation dose ( Dg) and swelling behavior of the resultant PNIPAAm gels has also been investigated.

  17. The effect of pre- and post-electron beam irradiation on the properties of NR/rCR blends

    NASA Astrophysics Data System (ADS)

    Salleh, Siti Zuliana; Ismail, Hanafi; Ahmad, Zulkifli

    2017-07-01

    The reutilize of rubber waste in the virgin rubber blends is arise as a solution for disposal problem. However, the disadvantage of the rubber waste addition is deteriorates the properties of the rubber blends. In this work, the effect of electron beam irradiation on different states of the natural rubber/recycled chloroprene rubber blends; uncured and cured states were investigated. Various rubber blends ratios were prepared using two-roll mill and then constant irradiated doses was used at 20kGy. From the result obtained, the tensile strength of the pre-cured rubber blends was higher than that post-cured. Similar observation can be obtained in the elongation at break and swelling percentage. The tensile modulus and crosslink density in post-cured blends are higher. The crosslink density calculation from swelling measurement supports the observations in the mechanical properties.

  18. Pore structure modification of diatomite as sulfuric acid catalyst support by high energy electron beam irradiation and hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Li, Chong; Zhang, Guilong; Wang, Min; Chen, Jianfeng; Cai, Dongqing; Wu, Zhengyan

    2014-08-01

    High energy electron beam (HEEB) irradiation and hydrothermal treatment (HT), were applied in order to remove the impurities and enlarge the pore size of diatomite, making diatomite more suitable to be a catalyst support. The results demonstrated that, through thermal, charge, impact and etching effects, HEEB irradiation could make the impurities in the pores of diatomite loose and remove some of them. Then HT could remove rest of them from the pores and contribute significantly to the modification of the pore size distribution of diatomite due to thermal expansion, water swelling and thermolysis effects. Moreover, the pore structure modification improved the properties (BET (Brunauer-Emmett-Teller) specific surface area, bulk density and pore volume) of diatomite and the catalytic efficiency of the catalyst prepared from the treated diatomite.

  19. Electron-beam irradiation inactivation of Salmonella: Effects on innate immunity and induction of protection against Salmonella enterica serovar Typhimurium challenge of chickens

    USDA-ARS?s Scientific Manuscript database

    Our laboratories are investigating the use of high-energy (10 MeV) Electron-Beam (E-beam) irradiation for its potential use in vaccine development. Ionizing radiation inactivates microorganisms by “direct and indirect” effects on nucleic acids and other cellular components. Though the cells are in...

  20. The effects of low-dose electron-beam irradiation and storage time and temperature on xanthophyllis, antioxidant capacity, and phenolics in the potato cultivar Atlantic

    USDA-ARS?s Scientific Manuscript database

    The effects of storage and low-dose electron-beam (e-beam) irradiation on health-promoting compounds were evaluated in the potato cultivar Atlantic. Tubers were either not exposed or subjected to 200 Gy and were either sampled immediately or stored at either 4 degrees C or ambient temperature for 10...

  1. Effect of 8 MeV electron beam irradiation on the structural and optical properties of CeO{sub 2} nanoparticles

    SciTech Connect

    Babitha, K.K.; Priyanka, K.P.; Sreedevi, A.; Ganesh, S.; Varghese, Thomas

    2014-12-15

    The effect of 8 MeV electron beam irradiation on the structural and optical properties of cerium oxide nanoparticles was investigated. Ceria nanoparticles were synthesized by chemical precipitation method, and characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible, photoluminescence and Raman spectroscopy. Ultraviolet–visible absorption spectra, photoluminescence and Raman spectra of beam irradiated samples were modified, and shifted to blue region, which were attributed to quantum size effect. Systematic observations found that nonstoichiometry, defects and size reduction caused by beam irradiation have great influence on optical band gap, blue shift, photoluminescence and Raman band modifications. Moreover, electron beam irradiation is a suitable technique to enhance the structural and optical properties of nanoceria by controlling the particle size, which may lead to potentially useful technological applications. - Highlights: • Investigated effect of beam irradiation on CeO{sub 2} nanoparticles • Beam irradiation caused size reduction and surface modification. • It increases microstrain, decreases d-spacing and broadens XRD peaks. • It also modifies optical band gap, absorption, PL and Raman bands.

  2. Indium redistribution in an InGaN quantum well induced by electron-beam irradiation in a transmission electron microscope

    SciTech Connect

    Li, T.; Hahn, E.; Gerthsen, D.; Rosenauer, A.; Strittmatter, A.; Reissmann, L.; Bimberg, D.

    2005-06-13

    The change of the morphology and indium distribution in an In{sub 0.12}Ga{sub 0.88}N quantum well embedded in GaN was investigated depending on the duration of electron-beam irradiation in a transmission electron microscope. Strain-state analysis based on high-resolution lattice-fringe images was used to determine quantitatively the local and average indium concentration of the InGaN quantum well. In-rich clusters were found already in the first image taken after 20 s of irradiation. The indium concentration in the clusters tends to increase with prolonged irradiation time. In contrast, the locally averaged indium concentration and the quantum-well width do not change within the first minute.

  3. Combined modulated electron and photon beams planned by a Monte-Carlo-based optimization procedure for accelerated partial breast irradiation.

    PubMed

    Palma, Bianey Atriana; Sánchez, Ana Ureba; Salguero, Francisco Javier; Arráns, Rafael; Sánchez, Carlos Míguez; Zurita, Amadeo Walls; Hermida, María Isabel Romero; Leal, Antonio

    2012-03-07

    The purpose of this study was to present a Monte-Carlo (MC)-based optimization procedure to improve conventional treatment plans for accelerated partial breast irradiation (APBI) using modulated electron beams alone or combined with modulated photon beams, to be delivered by a single collimation device, i.e. a photon multi-leaf collimator (xMLC) already installed in a standard hospital. Five left-sided breast cases were retrospectively planned using modulated photon and/or electron beams with an in-house treatment planning system (TPS), called CARMEN, and based on MC simulations. For comparison, the same cases were also planned by a PINNACLE TPS using conventional inverse intensity modulated radiation therapy (IMRT). Normal tissue complication probability for pericarditis, pneumonitis and breast fibrosis was calculated. CARMEN plans showed similar acceptable planning target volume (PTV) coverage as conventional IMRT plans with 90% of PTV volume covered by the prescribed dose (D(p)). Heart and ipsilateral lung receiving 5% D(p) and 15% D(p), respectively, was 3.2-3.6 times lower for CARMEN plans. Ipsilateral breast receiving 50% D(p) and 100% D(p) was an average of 1.4-1.7 times lower for CARMEN plans. Skin and whole body low-dose volume was also reduced. Modulated photon and/or electron beams planned by the CARMEN TPS improve APBI treatments by increasing normal tissue sparing maintaining the same PTV coverage achieved by other techniques. The use of the xMLC, already installed in the linac, to collimate photon and electron beams favors the clinical implementation of APBI with the highest efficiency.

  4. In situ TEM observation of novel chemical evolution of MnBr2 catalyzed by Cu under electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Bai, Xianwei; Guan, Xiangxiang; Shen, Xi; Yao, Yuan; Wang, Yanguo; Zou, Bingsuo; Yu, Richeng

    2017-10-01

    Manganese bromide has attracted enormous attention for its applications in the syntheses of organic-inorganic hybrid compounds. A complete understanding of structural and chemical stabilities of MnBr2 is important for controlling its properties. Here, we focus on the irradiation resistance of MnBr2. The chief purpose of this research is reached by in situ transmission electron microscopy. It is demonstrated that the deliquescent MnBr2 powder is prone to adsorb the vapor in air, and the hydrous MnBr2 can be decomposed under its continuous exposure to electron beam, indicated by a transmission electron microscope via the catalysis of Cu grid at room temperature.

  5. Microencapsulated antimicrobial compounds as a means to enhance electron beam irradiation treatment for inactivation of pathogens on fresh spinach leaves.

    PubMed

    Gomes, Carmen; Moreira, Rosana G; Castell-Perez, Elena

    2011-08-01

    Recent outbreaks associated to the consumption of raw or minimally processed vegetable products that have resulted in several illnesses and a few deaths call for urgent actions aimed at improving the safety of those products. Electron beam irradiation can extend shelf-life and assure safety of fresh produce. However, undesirable effects on the organoleptic quality at doses required to achieve pathogen inactivation limit irradiation. Ways to increase pathogen radiation sensitivity could reduce the dose required for a certain level of microbial kill. The objective of this study was to evaluate the effectiveness of using natural antimicrobials when irradiating fresh produce. The minimum inhibitory concentration of 5 natural compounds and extracts (trans-cinnamaldehyde, eugenol, garlic extract, propolis extract, and lysozyme with ethylenediaminetetraacetate acid (disodium salt dihydrate) was determined against Salmonella spp. and Listeria spp. In order to mask odor and off-flavor inherent of several compounds, and to increase their solubility, complexes of these compounds and extracts with β-cyclodextrin were prepared by the freeze-drying method. All compounds showed bacteriostatic effect at different levels for both bacteria. The effectiveness of the microencapsulated compounds was tested by spraying them on the surface of baby spinach inoculated with Salmonella spp. The dose (D₁₀ value) required to reduce the bacterial population by 1 log was 0.190 kGy without antimicrobial addition. The increase in radiation sensitivity (up to 40%) varied with the antimicrobial compound. These results confirm that the combination of spraying microencapsulated antimicrobials with electron beam irradiation was effective in increasing the killing effect of irradiation. Foodborne illness outbreaks attributed to fresh produce consumption have increased and present new challenges to food safety. Current technologies (water washing or treating with 200 ppm chlorine) cannot

  6. Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

    SciTech Connect

    Thomé, Lionel Debelle, Aurélien; Garrido, Frédérico; Sattonnay, Gaël; Mylonas, Stamatis; Velisa, Gihan; Miro, Sandrine; Trocellier, Patrick; Serruys, Yves

    2015-03-14

    Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (S{sub n}) and Electronic (S{sub e}) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (S{sub n} and S{sub e}), whereas single low-energy irradiation (S{sub n} alone) or even sequential (S{sub n} + S{sub e}) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between S{sub n} and S{sub e} in ion-irradiation experiments. This work is interesting for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where recovery S{sub n}/S{sub e} effects may preserve the integrity of nuclear devices.

  7. Electron beam irradiation of high density polyethylene pellets for thermal energy storage. Final report of Task 1 and Task 2, January 5, 1979-January 4, 1980

    SciTech Connect

    Davison, J.E.; Salyer, I.O.

    1980-05-01

    The objective of this project was to define the electron beam irradiation conditions required to prepare thermally form stable high crystallinity polyethylene (HDPE) pellets which are suitable for thermal energy storage (TES) applications in the temperature interval of 120/sup 0/ to 140/sup 0/C. The optimum material and conditions for electron beam x-linking via evaluation of thermal form stability and retained heat of fusion of HDPE pellets in a laboratory (5 lb) TES unit was defined. 250 pounds of crosslinked HDPE pellets under the optimum conditions defined in Task 1 were manufactured and evaluated for stability to extensive thermocycling in a pilot plant TES unit. Four different HDPE specimens were irradiated under different conditions of the total radiation dose received by the pellets, the electron beam accelerating potential, the electron beam current, the effect of inert atmospheres during irradiation processing, and the effect of stirring the HDPE pellets during the irradiation processing. The experimental values of the heat of fusion and the melting temperature of the irradiated HDPE pellets were measured and compared to the values of the as-received pellets to evaluate the effect of irradiation processing. The results showed that HDPE pellets irradiated to a dose of 8 megarads have sufficient thermal stability and retained heat of fusion to be used as TES material. The manufacture of 15,000 lb of cross linked HDPE pellets for large-scale evaluation TES material for home heating and cooling systems is recommended. (LCL)

  8. Best use of high-voltage, high-powered electron beams: a new approach to contract irradiation services

    NASA Astrophysics Data System (ADS)

    Watanabe, T.

    2000-03-01

    Japan's first high-voltage, high-powered electron beam processing center is scheduled to come on-line during the first half of 1999. The center explores both challenges and opportunities of how best to use the 200 kW 10 MeV unit and its 5 MeV X-ray line. In particular, Nuclear Fuel Industries, Ltd. (NFI) has expanded the traditional model of a contract irradiation facility to include a much broader scope of services such as door-to-door transport, storage, and direct distribution to its customer's end-users. The new business scope not only finds new value-added components in a competitive marketplace, but serves to provide a viable mechanism to take advantage of the processing logistics of high throughput irradiation units. As such, the center features a high-capacity warehousing system, monitored by a newly developed PCMS (plant control management system), which has been comprehensively integrated into the irradiation unit's handling system, and will require only minimal human resources for its high rate of material handling. The identification and development of initial markets for this first unit will be discussed, concluding with how this same operational philosophy can help break open new irradiation segments in medical devices, consumer goods, animal feed, and food markets and NFI's other efforts in these same areas.

  9. On problems of reducing energy consumption for irradiation of flue gas in the electron beam gas treatment technology

    NASA Astrophysics Data System (ADS)

    Fainchtein, O. L.; Sagaidak, M. V.; Morgunov, V. V.

    2002-11-01

    The electron beam (EB) flue gas treatment technology is presented as a combination of radiation chemical transformations and phase transitions. Some theoretical and experimental evidence is presented which suggests that there are two mechanisms to substantially reduce the energy consumption for gas irradiation: droplet mechanism and a mechanism related to specific EB current density (current-mechanism). Both the mechanisms are based on chain reactions of oxidation. The 100,000 m 3/h Slavyanskaya Electron Beam Industrial Plant (developed by our Institute "Energostal", being built in Ukraine) is described. The plant design is aimed at solving the two main problems of the EB scrubbing technology: reduction of energy consumption for irradiation (using a droplet mechanism) and more reliable collection of salt particles (using wet particles collectors). The paper is devoted to EB flue gas treatment technology to remove SO 2 and NO x from flue gas, its present status and the prospects of its further development and optimization, special attention being paid to reduction of energy consumption.

  10. Energy deposition, heat flow, and rapid solidification during laser and electron beam irradiation of materials

    SciTech Connect

    White, C.W.; Aziz, M.J.

    1985-10-01

    The fundamentals of energy deposition, heat flow, and rapid solidification during energy deposition from lasers and electron beams is reviewed. Emphasis is placed on the deposition of energy from pulsed sources (10 to 100 ns pulse duration time) in order to achieve high heating and cooling rates (10/sup 8/ to 10/sup 10/ /sup 0/C/s) in the near surface region. The response of both metals and semiconductors to pulsed energy deposition is considered. Guidelines are presented for the choice of energy source, wavelength, and pulse duration time.

  11. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing.

    PubMed

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-19

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm(-1) K(-2)), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

  12. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing

    NASA Astrophysics Data System (ADS)

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-01

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm-1 K-2), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

  13. The curvature of sensitometric curves for Kodak XV-2 film irradiated with photon and electron beams.

    PubMed

    van Battum, L J; Huizenga, H

    2006-07-01

    Sensitometric curves of Kodak XV-2 film, obtained in a time period of ten years with various types of equipment, have been analyzed both for photon and electron beams. The sensitometric slope in the dataset varies more than a factor of 2, which is attributed mainly to variations in developer conditions. In the literature, the single hit equation has been proposed as a model for the sensitometric curve, as with the parameters of the sensitivity and maximum optical density. In this work, the single hit equation has been translated into a polynomial like function as with the parameters of the sensitometric slope and curvature. The model has been applied to fit the sensitometric data. If the dataset is fitted for each single sensitometric curve separately, a large variation is observed for both fit parameters. When sensitometric curves are fitted simultaneously it appears that all curves can be fitted adequately with a sensitometric curvature that is related to the sensitometric slope. When fitting each curve separately, apparently measurement uncertainty hides this relation. This relation appears to be dependent only on the type of densitometer used. No significant differences between beam energies or beam modalities are observed. Using the intrinsic relation between slope and curvature in fitting sensitometric data, e.g., for pretreatment verification of intensity-modulated radiotherapy, will increase the accuracy of the sensitometric curve. A calibration at a single dose point, together with a predetermined densitometer-dependent parameter ODmax will be adequate to find the actual relation between optical density and dose.

  14. Continuous and breakdown currents in cold-plasma coated Mylar[reg sign] foils under irradiation by nonpenetrating electron beams

    SciTech Connect

    Gross, B.; Guenther, P. )

    1993-04-01

    Breakdown and flash-over effects are known to occur in thin polymer foils used as thermal blankets in space satellites, where they are exposed to irradiation by nonpenetrating space electrons. These effects are investigated by means of a Split Faraday Cup system mounted under an electron gun [1]. Continuous and breakdown currents are measured from a metal ring electrode at the surface of incidence and from a rear electrode, respectively. The equivalent circuit of the system is developed. Measurements were carried out on Mylar foils uncoated or coated with aluminum, plasma-deposited SiO[sub 2] or Si[sub 3]N[sub 4](p-SiO[sub 2] or p-Si[sub 3]N[sub 4]), or electron-beam evaporated SiO[sub 2]. It was found, that some plasma-deposited coatings form a conductive layer under irradiation and reduce breakdown effects. But after termination of the electron bombardment discharge and breakdown effects were observed for all samples except those aluminized on both surfaces.

  15. Synthesis of carbon-supported PtRh random alloy nanoparticles using electron beam irradiation reduction method

    NASA Astrophysics Data System (ADS)

    Matsuura, Yoshiyuki; Seino, Satoshi; Okazaki, Tomohisa; Akita, Tomoki; Nakagawa, Takashi; Yamamoto, Takao A.

    2016-05-01

    Bimetallic nanoparticle catalysts of PtRh supported on carbon were synthesized using an electron beam irradiation reduction method. The PtRh nanoparticle catalysts were composed of particles 2-3 nm in size, which were well dispersed on the surface of the carbon support nanoparticles. Analyses of X-ray diffraction and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy revealed that the PtRh nanoparticles have a randomly alloyed structure. The lattice constant of the PtRh nanoparticles showed good correlation with Vegard's law. These results are explained by the radiochemical formation process of the PtRh nanoparticles. Catalytic activities of PtRh/C nanoparticles for ethanol oxidation reaction were found to be higher than those obtained with Pt/C.

  16. Modifications in the structural and optical properties of nanocrystalline CaWO4 induced by 8 MeV electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Aloysius Sabu, N.; Priyanka, K. P.; Ganesh, Sanjeev; Varghese, Thomas

    2016-06-01

    In this article we report the post irradiation effects in the structural and optical properties of nanocrystalline calcium tungstate synthesized by chemical precipitation and heat treatment. The samples were subjected to different doses of high-energy electron beam obtained from an 8 MeV Microton. Investigations using X-ray diffraction, scanning electron microscopy and Raman spectra confirmed changes in particle size and structural parameters. However, no phase change was detected for irradiated samples. The stretching/compressive strain caused by high energy electrons is responsible for the slight shift in the XRD peaks of irradiated samples. Modifications in the morphology of different samples were confirmed by scanning electron microscopy. Ultraviolet-visible absorption studies showed variations in the optical band gap (4.08-4.25 eV) upon electron-beam irradiation. New photoluminescence behaviour in electron beam irradiated nanocrystalline CaWO4 was evidenced. A blue shift of the PL peak with increase in intensity was observed in all the irradiated samples.

  17. Strain improvement of Trichoderma viride for increased cellulase production by irradiation of electron and (12)C(6+)-ion beams.

    PubMed

    Li, Zhaozhou; Chen, Xiujin; Li, Zhili; Li, Daomin; Wang, Yao; Gao, Hongli; Cao, Li; Hou, Yuze; Li, Songbiao; Liang, Jianping

    2016-06-01

    To improve cellulase production and activity, Trichoderma viride GSICC 62010 was subjected to mutation involving irradiation with an electron beam and subsequently with a (12)C(6+)-ion beam. Mutant CIT 626 was the most promising cellulase producer after preliminary and secondary screening. Soluble protein production and cellulase activities were increased mutifold. The optimum temperature, pH and culture time for the maximum cellulase production of the selected mutant were 35 °C, pH 5 and 6 days. The highest cellulase production was obtained using wheat bran. The prepared cellulases from T. viride CIT 626 had twice the hydrolytic performance with sawdust (83 %) than that from the parent strain (42.5 %). Furthermore, molecular studies demonstrated that there were some key mutation sites suggesting that some amino acid changes in the protein caused by base mutations had led to the enhanced cellulase production and activity. Mutagenesis with electron and (12)C(6+)-ion beams could be developed as an effective tool for improvement of cellulase producing strains.

  18. Clinical implementation of combined modulated electron and photon beams with conventional MLC for accelerated partial breast irradiation.

    PubMed

    Míguez, Carlos; Jiménez-Ortega, Elisa; Palma, Bianey A; Miras, Hector; Ureba, Ana; Arráns, Rafael; Carrasco-Peña, Francisco; Illescas-Vacas, Ana; Leal, Antonio

    2017-07-01

    To report the clinical implementation of a novel external beam radiotherapy technique for accelerated partial breast irradiation treatments based on combined electron and photon modulated beams radiotherapy (MERT+IMRT) with conventional MLC. A group of patients was selected to test the viability of the technique. The prescribed dose was 38.5Gy, following a hypofractionated schema, and the structures were defined following the NSABP-B39/RTOG-0413 protocol. The plans were calculated with an in-house Monte Carlo based planning system to consider explicitly the particle interactions with the MLC. An ad-hoc breast phantom was designed for a specific QA protocol. A reduced SSD was used for electron beams. Toxicity and cosmetic effects were assessed at every follow-up visit. All the plans achieved the dosimetric objectives and fulfilled the specific quality assurance protocol. Treatment delivery did not entail additional drawbacks for the clinical routine. Moderate or severe grade of toxicity was not reported, and the cosmetic results were comparable to those obtained with other APBI techniques. Results showed that MERT+IMRT with the MLC is a feasible and secure technique, and easy to be extended to other centers with the implementation of the adequate software for planning. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Preparation of nanocomposite γ-Al2O3/polyethylene separator crosslinked by electron beam irradiation for lithium secondary battery

    NASA Astrophysics Data System (ADS)

    Nho, Young-Chang; Sohn, Joon-Yong; Shin, Junhwa; Park, Jong-Seok; Lim, Yoon-Mook; Kang, Phil-Hyun

    2017-03-01

    Although micro-porous membranes made of polyethylene (PE) offer excellent mechanical strength and chemical stability, they exhibit large thermal shrinkage at high temperature, which causes a short circuit between positive and negative electrodes in cases of unusual heat generation. We tried to develop a new technology to reduce the thermal shrinkage of PE separators by introducing γ-Al2O3 particles treated with coupling agent on PE separators. Nanocomposite γ-Al2O3/PE separators were prepared by the dip coating of polyethylene(PE) separators in γ-Al2O3/poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP)/crosslinker (1,3,5-trially-1,3,5-triazine-2,4,6(1 H,3 H,5 H)-trione (TTT) solution with humidity control followed by electron beam irradiation. γ-Al2O3/PVDF-HFP/TTT (95/5/2)-coated PE separator showed the highest electrolyte uptake (157%) and ionic conductivity (1.3 mS/cm). On the basis of the thermal shrinkage test, the nanocomposite γ-Al2O3/PE separators containing TTT irradiated by electron beam exhibited a higher thermal resistance. Moreover, a linear sweep voltammetry test showed that the irradiated nanocomposite γ-Al2O3/PE separators have electrochemical stabilities of up to 5.0 V. In a battery performance test, the coin cell assembled with γ-Al2O3/PVDF-HFP/TTT-coated PE separator showed excellent discharge cycle performance.

  20. Electron-beam irradiation induced phase transformation, optical absorption and surface-enhanced Raman scattering of Indium tin alloy thin films

    NASA Astrophysics Data System (ADS)

    Wei, Wenzuo; Hong, Ruijin; Meng, Yan; Tao, Chunxian; Zhang, Dawei

    2017-06-01

    Electron beam (EB) irradiation experiments on Indium-tin (In-Sn) alloy thin films are reported. The structure and the optical properties of the samples were investigated by atomic force microscopy, X-ray diffraction, UV-vis-NIR double beam spectrometer and Raman system, respectively. Those results show that EB irradiation has the effects of changing the preferred orientation, improving the crystalline, enhancing the absorption, and improving the surface-enhanced Raman scattering (SERS) of samples. In addition, Finite-Difference Time-Domain (FDTD) was performed for the surface plasmon resonance properties of the as-irradiated samples, and the results are in good agreement with the experiments.

  1. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    NASA Astrophysics Data System (ADS)

    Lucero, J. F.; Rojas, J. I.

    2016-07-01

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient's entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  2. Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

    SciTech Connect

    Thome, Lionel; Debelle, Aurelien; Garrido, Frederico; Trocellier, Patrick; Serruys, Yves; Miro, Sandrine

    2013-04-08

    Single and dual-beam irradiations of oxide (c-ZrO{sub 2}, MgO, Gd{sub 2}Ti{sub 2}O{sub 7}) and carbide (SiC) single crystals were performed to study combined effects of nuclear (S{sub n}) and electronic (S{sub e}) energy losses. Rutherford backscattering experiments in channeling conditions show that the S{sub n}/S{sub e} cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO{sub 2} and Gd{sub 2}Ti{sub 2}O{sub 7}. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative S{sub n}/S{sub e} effects may lead to the preservation of the integrity of nuclear devices.

  3. WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Hao, S. Z.; Zhang, Y.; Xu, Y.; Gey, N.; Grosdidier, T.; Dong, C.

    2013-11-01

    High current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 μs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC1-x, Co3W9C4, Co3W3C phases and graphite precipitate domains ˜50 nm. The friction coefficient of modified surface decreased to ˜0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 × 10-5 mm3/min to 6.3 × 10-6 mm3/min, showing a significant self-lubricating effect.

  4. Comparison of the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation

    PubMed Central

    Vaishnavi, C; Kavitha, S; Narayanan, L Lakshmi

    2010-01-01

    Aim: To compare the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation. Materials and Methods: Forty specimens were randomly assigned into four groups of ten each and were subjected to various post curing methods. Fracture toughness and wear resistance tests were performed and the results were tabulated and analyzed statistically using Kruskal Wallis and Mann-Whitney U test. Results: It was found that Inlay system showed higher values followed by electron beam irradiation. Conclusion: Electron beam irradiation of dental composites gives comparable mechanical properties to other post curing systems. It can be concluded that further studies with increased radiation dose should be performed to improve the mechanical properties of indirect composites. PMID:21116390

  5. Comparison of the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation.

    PubMed

    Vaishnavi, C; Kavitha, S; Narayanan, L Lakshmi

    2010-07-01

    To compare the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation. Forty specimens were randomly assigned into four groups of ten each and were subjected to various post curing methods. Fracture toughness and wear resistance tests were performed and the results were tabulated and analyzed statistically using Kruskal Wallis and Mann-Whitney U test. It was found that Inlay system showed higher values followed by electron beam irradiation. Electron beam irradiation of dental composites gives comparable mechanical properties to other post curing systems. It can be concluded that further studies with increased radiation dose should be performed to improve the mechanical properties of indirect composites.

  6. The effect of electron-beam irradiation and halogen-free flame retardants on properties of poly butylene terephthalate

    NASA Astrophysics Data System (ADS)

    Hooshangi, Zhila; Feghhi, Seyed Amir Hossein; Sheikh, Nasrin

    2015-03-01

    Engineering plastics like Poly (butylene terephthalate) due to their desirable properties have various industrial applications. Neat PBT is highly combustible, so it is necessary to improve significantly its fire retardancy to meet the fire safety requirements. The combustion performance of PBT can be improved by addition of appropriate flame retardant additives. In this study we have investigated the effect of halogen free flame retardants, i.e. melamine and aluminum phosphate, and instantaneously electron beam radiation-induced crosslinking in the presence of Triallyl cyanurate on various properties of PBT. The results of gel content showed that a dose range of 200-400 kGy leads to high cross linked structure in this polymer. Also mechanical experiments showed that its structure became rigid and fragile due to irradiation. Radiation crosslinking of this polymer made its dielectric loss coefficient ten times lower than non-irradiated polymer, but had no effect on its dielectric constant. Moreover the addition of the fire retardant additives as impurity decreased the dielectric loss coefficient. TGA analysis in nitrogen exhibited that irradiation increases char formation and use of the fire retardant additives leads to reduction of onset temperature and formation of higher char quantity than pure PBT. According to the results of UL-94, irradiated samples burned with lower speed and less dripping in vertical and horizontal positions than pure polymer. Finally irradiation of the polymers containing fire retardant additives with a dose of 400 kGy led to self-extinguishing and non-dripping and reach to V-0 level in the UL-94 V.

  7. Effect of low-dose electron beam irradiation on quality of ground beef patties and raw, intact carcass muscle pieces.

    PubMed

    Kundu, Devapriya; Holley, Richard

    2013-06-01

    The objectives of this study were to determine the effects of a low-dose (≤1 kGy), low-penetration electron beam on the sensory qualities of (1) raw muscle pieces of beef and (2) cooked ground beef patties. Outside flat, inside round, brisket and sirloin muscle pieces were used as models to demonstrate the effect of irradiation on raw beef odor and color, as evaluated by a trained panel. Ground beef patties were also evaluated by a trained panel for tenderness, juiciness, beef flavor, and aroma at 10%, 20%, and 30% levels of fat, containing 0% (control), 10%, 20%, 50%, and 100% irradiated meat. With whole muscle pieces, the color of controls appeared more red (P < 0.05) than irradiated muscles, however, both control and treatments showed a gradual deterioration in color over 14 d aerobic storage at 4 °C. Off-aroma intensity of both control and treatments increased with storage time, but by day 14, the treated muscles showed significantly (P < 0.05) less off-aroma than the controls, presumably as a result of a lower microbial load. It was found that a 1 kGy absorbed dose had minimal effects on the sensory properties of intact beef muscle pieces. Irradiation did not have a significant effect (P > 0.05) on any of the sensory attributes of the patties. Low-dose irradiation of beef trim to formulate ground beef appears to be a viable alternative processing approach that does not affect product quality.

  8. Fast crystallization of amorphous Gd{sub 2}Zr{sub 2}O{sub 7} induced by thermally activated electron-beam irradiation

    SciTech Connect

    Huang, Zhangyi; Qi, Jianqi Zhou, Li; Feng, Zhao; Yu, Xiaohe; Gong, Yichao; Yang, Mao; Wei, Nian; Shi, Qiwu; Lu, Tiecheng

    2015-12-07

    We investigate the ionization and displacement effects of an electron-beam (e-beam) on amorphous Gd{sub 2}Zr{sub 2}O{sub 7} synthesized by the co-precipitation and calcination methods. The as-received amorphous specimens were irradiated under electron beams at different energies (80 keV, 120 keV, and 2 MeV) and then characterized by X-ray diffraction and transmission electron microscopy. A metastable fluorite phase was observed in nanocrystalline Gd{sub 2}Zr{sub 2}O{sub 7} and is proposed to arise from the relatively lower surface and interface energy compared with the pyrochlore phase. Fast crystallization could be induced by 120 keV e-beam irradiation (beam current = 0.47 mA/cm{sup 2}). The crystallization occurred on the nanoscale upon ionization irradiation at 400 °C after a dose of less than 10{sup 17} electrons/cm{sup 2}. Under e-beam irradiation, the activation energy for the grain growth process was approximately 10 kJ/mol, but the activation energy was 135 kJ/mol by calcination in a furnace. The thermally activated ionization process was considered the fast crystallization mechanism.

  9. Comparative effects of gamma and electron beam irradiation on the antioxidant potential of Portuguese chestnuts (Castanea sativa Mill.).

    PubMed

    Carocho, Márcio; Antonio, Amilcar L; Barros, Lillian; Bento, Albino; Botelho, M Luisa; Kaluska, Iwona; Ferreira, Isabel C F R

    2012-10-01

    Chestnuts (Castanea sativa Mill.) are widely consumed all over the world, and have been recently studied for their antioxidant potential. The present study reports the effect of e-beam and gamma radiation (doses of 0, 0.5, 1 and 3 kGy) on the antioxidant potential of Portuguese chestnuts. Irradiation might be an alternative preservation method, since Methyl Bromide, a widely used fumigant, was banished by the European Union in 2010 due to its toxicity. The antioxidant activity was evaluated through 2,2-diphenyl-1-pycrylhydrazyl (DPPH) free radical scavenging activity assay, reducing power by the Ferricyanide/Prussian blue assay, and lipid peroxidation inhibition by β-carotene/linoleate and thiobarbituric acid reactive substances (TBARS) assays. The analysis of total phenolics and flavonoids was performed by spectrophotometric assays. Irradiated samples preserved total phenolics content (but not flavonoids) and revealed higher antioxidant activity (lower EC50 values) than the control samples. The most indicated doses to maintain antioxidants content, and to increase antioxidant activity were 1 and 3 kGy for electron beam and gamma radiation, respectively.

  10. A pilot study investigating intraoperative electron beam irradiation in the treatment of ovarian malignancies

    SciTech Connect

    Konski, A.A.; Neisler, J.; Phibbs, G.; Bronn, D.G.; Dobelbower, R.R. Jr. )

    1990-07-01

    Intraoperative electron beam radiation therapy (IOEBRT) in the treatment of ovarian malignancies was investigated at the Clement O. Miniger Radiation Oncology Center (COMROC). Nine patients were operated in the COMROC IOEBRT operating amphitheater and five were found to have disease sufficiently limited to allow for IOEBRT. The patients' ages ranged from 13 to 80 (median 53) years. Five patients had serous cystadenocarcinoma, one papillary adenocarcinoma, one mixed germ cell tumor, one squamous cell carcinoma, and one granular cell tumor of the ovary. The median survival of the non-IOEBRT group was 13 (range 12-29) months, while the IOEBRT group's median survival was 14 (range 18-46) months. All of the patients tolerated IOEBRT well without addition to the surgical morbidity.

  11. Electron beam irradiation of maltodextrin and cinnamyl alcohol mixtures: influence of glycerol on cross-linking.

    PubMed

    Khandal, Dhriti; Aggarwal, Manjeet; Suri, Gunjan; Coqueret, Xavier

    2015-03-06

    The influence of glycerol on the electron beam-induced changes in maltodextrins-cinnamyl alcohol (CA) blends is examined with respect to its influence on the degree of chain scission, grafting, and cross-linking. The study is relevant to radiation-induced polysaccharide modification, specifically in the perspective of using blended starch as a thermoplastic material, where glycerol is commonly used as a plasticizer. In the absence of CA, glycerol protects maltodextrin from chromophore formation onto the main chain, but also induces more chain scission. The presence of CA provides efficient radiation-protection against scission. Glycerol is shown to affect the interaction between maltodextrin and CA, most likely in the form of an inclusion complex when glycerol is absent. The global behavior under radiation is therefore governed by the physical interactions between the blend constituents rather than on the role of glycerol role as a plasticizer, or as an OH˙ radical scavenger.

  12. Effects of electron beam irradiation on the property behaviour of poly(ether-block-amide) blended with various stabilisers

    NASA Astrophysics Data System (ADS)

    Murray, Kieran A.; Kennedy, James E.; Barron, Valerie; McEvoy, Brian; Vrain, Olivier; Ryan, Damien; Cowman, Richard; Higginbotham, Clement L.

    2015-05-01

    Radiosterilisation can induce modifications and/or degradation to transpire in poly(ether-block-amide) (PEBA) following irradiation. The current investigation utilises combined synergistic mixtures of stabilisers to minimise these effects, by melt blending them with the PEBA material. Hindered amine stabilisers (HAS), primary antioxidants and secondary antioxidants were the stabilisers incorporate to reduce/eliminate the effects of 50 kGy electron beam irradiation dose on the material. Results were discussed by comparing the stabilising efficiency of mixtures on the PEBA material in contrast to the control sample. Dynamic frequency sweeps demonstrated the formation of crosslinks, where the degree of crosslinking was dependent on the combination of stabilisers mixed in the base material (PEBA). The storage modulus displayed that PEBA blended with Irganox 565 had very slight changes in contrast to all other samples following irradiation. However, since this sample is a phenol containing system, severe discolouration was observed in comparison to other samples due to the oxidation of the hindered phenol. Overall, this study provides compelling evidence that a combined synergistic mixture of Irganox 565 (multifunctional phenolic antioxidant) and Tinuvin 783 (hindered amide light stabiliser) with PEBA, resulted in the best radiation stability.

  13. Analysis of mixing conditions and multistage irradiation impact on NOx removal efficiency in the electron beam flue gas treatment process.

    PubMed

    Pawelec, Andrzej; Dobrowolski, Andrzej

    2017-01-01

    In the process of electron beam flue gas treatment (EBFGT), most energy is spent on NOx removal. The dose distribution in the reactor is not uniform and the flue gas flow pattern plays an important role in the process efficiency. It was found that proper construction of the reactor may increase the energy efficiency of the process. The impact of the number of irradiation stages and mixing conditions on NOx removal efficiency was investigated for an ideal case and a practical solution was presented and compared with previously known EBFGT reactor constructions. The research was performed by means of computational fluid dynamics methods in combination with empirical Wittig formula. Two versions of dose distribution were taken for calculations. The results of the research show that for an ideal case, application of multistage irradiation and interstage mixing may reduce the energy consumption in the process by up to 39%. On the other side, simulation of reactor construction modification for two-stage irradiation results in 25% energy consumption reduction. The results of presented case study may be applied for improving the existing reactors and proper design of future installations.

  14. Inactivation of Escherichia coli O157:H7 and other naturally occurring microorganisms in apple cider by electron beam irradiation.

    PubMed

    Wang, Hui; Reitmeier, Cheryll A; Glatz, Bonita A

    2004-08-01

    Two Escherichia coli O157:H7 strains, SEA 13 B88 gfp 73ec and B6-914 gfp 90ec, together with two bacteria, three yeasts, and two molds that were randomly selected from a collection of microorganisms found on apples or in apple cider, were inoculated into apple cider and subjected to electron beam irradiation at several doses between 0.0 and 2.3 kGy at the Iowa State University Linear Accelerator Facility. The D-values for the E. coli O157:H7 strains ranged between 0.25 and 0.34 kGy; the D-values for most of the normal flora from apples ranged between 0.24 and 0.59 kGy. By taking into account possible variations in treatment conditions, it was calculated that irradiation at 2.47 kGy should achieve a 5-log reduction of E. coli O157:H7 in apple cider at the 95% confidence level. Naturally occurring yeasts might survive such irradiation treatment.

  15. The effect of electron beam irradiation on preparation of sago starch/polyvinyl alcohol foams

    NASA Astrophysics Data System (ADS)

    Wongsuban, Benchamaporn; Muhammad, Kharidah; Ghazali, Zulkafli; Hashim, Kamaruddin; Ali Hassan, Muhammad

    2003-10-01

    Blends of sago starch (SS)/polyvinyl alcohol (PVA) were irradiated with doses ranging from 10 to 30 kGy. Foams were then produced from these irradiated blends using a microwave. Changes in the degree of crosslinking, gel strength, thermal stability morphology of blends and linear expansion of foam with increasing irradiation doses were subsequently investigated. It was observed that the degree of crosslinking was important in maximizing the positive effect on foams produced. The gel strength of SS/PVA blends was affected by the irradiation. The crosslinking by the irradiation enhanced the thermal stability of SS/PVA blends. The results also revealed that the highest linear expansion of foams could be produced by irradiation blends at 15 kGy. Changes in blend morphology were observed upon irradiation.

  16. Effects of gamma ray and electron beam irradiation on the mechanical, thermal, structural and physicochemical properties of poly (ether-block-amide) thermoplastic elastomers.

    PubMed

    Murray, Kieran A; Kennedy, James E; McEvoy, Brian; Vrain, Olivier; Ryan, Damien; Cowman, Richard; Higginbotham, Clement L

    2013-01-01

    Both gamma ray and electron beam irradiation are widely used as a means of medical device sterilisation. However, it is known that the radiation produced by both processes can lead to undesirable changes within biomedical polymers. The main objective of this research was to conduct a comparative study on the two key radiosterilisation methods (gamma ray and electron beam) in order to identify the more detrimental process in terms of the mechanical, structural, chemical and thermal properties of a common biomedical grade polymer. Poly (ether-block-amide) (PEBA) was prepared by injection moulding ASTM testing specimens and these were exposed to an extensive range of irradiation doses (5-200 kGy) in an air atmosphere. The effect of varying the irradiation dose concentration on the resultant PEBA properties was apparent. For instance, the tensile strength, percentage elongation at break and shore D hardness can be increased/decreased by controlling the aforementioned criteria. In addition, it was observed that the stiffness of the material increased with incremental irradiation doses as anticipated. Melt flow index demonstrated a dramatic increase in the melting strength of the material indicating a sharp increase in molecular weight. Conversely, modulated differential scanning calorimetry established that there were no significant alterations to the thermal transitions. Noteworthy trends were observed for the dynamic frequency sweeps of the material, where the crosslink density increased according to an increase in electron beam irradiation dose. Trans-vinylene unsaturations and the carbonyl group concentration increased with an increment in irradiation dose for both processes when observed by FTIR. The relationship between the irradiation dose rate, mechanical properties and the subsequent surface properties of PEBA material is further elucidated throughout this paper. This study revealed that the gamma irradiation process produced more adverse effects in the PEBA

  17. Investigation of electron beam irradiation effects on anti-nutritional factors, chemical composition and digestion kinetics of whole cottonseed, soybean and canola seeds

    NASA Astrophysics Data System (ADS)

    Ebrahimi-Mahmoudabad, S. R.; Taghinejad-Roudbaneh, M.

    2011-12-01

    This study was completed to determine effects of electron beam (EB) irradiation at doses of 15, 30 and 45 kGy on anti-nutritional factors, ruminal degradation and in vitro crude protein (CP) digestibility of whole cottonseed (WCS), soybean (SB) and canola seeds (CS). EB-irradiation eliminated completely ( P<0.001) phytic acid of WCS, SB and CS at a dose of 30 kGy. EB-irradiation decreased linearly ( P<0.001) the total glucosinolate content of CS. Trypsin inhibitor activity of 15, 30 and 45 kGy EB-irradiated SB was decreased by 19, 73 and 88%, respectively. Free gossypol content of WCS was reduced linearly ( P<0.001) by irradiation. EB-irradiation increased linearly ( P<0.001) CP digestibility of feeds. In conclusion, EB-irradiation was an effective processing method for improving the nutritive value of WCS, SB and CS.

  18. Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile butadiene rubber under electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Yasin, Tariq; Ahmed, Shamshad; Ahmed, Munir; Yoshii, Fumio

    2005-06-01

    An investigation has been undertaken to find out the effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of the acrylonitrile-butadiene rubber (NBR) crosslinked by electron beam (EB). The PFMs used were diethylene glycol dimethacrylate, trimethylol propane trimethacrylate and trimethylol propane triacrylate. The physical properties of EB-irradiated NBR sheets were evaluated by measuring the tensile strength, elongation percent at break, hardness and gel fraction. The results showed a remarkable increase in tensile strength, hardness and gel fraction as the concentration of PFMs was increased from 1 part per hundred (phr) to 5 phr in the NBR samples whereas elongation percent decreased in a steady manner. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by the corresponding increase in gel content.

  19. Modelling study of NOx removal in oil-fired waste off-gases under electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Zwolińska, Ewa; Sun, Yongxia; Chmielewski, A. G.; Nichipor, H.; Bulka, S.

    2015-08-01

    Computer simulations for high concentration of NOx removal from oil-fired waste off-gases under electron beam irradiation were carried out by using the Computer code "Kinetic" and GEAR method. 293 reactions involving 64 species were used for the modelling calculations. The composition of simulated oil-fired off-gas was the same as the experimental conditions. The calculations were made for following system: (75.78% N2+11.5% CO2+8.62% H2O+4.1% O2), NOx concentration varies from 200 ppm to 1500 ppm. Calculation results qualitatively agree with the experimental results. Furthermore the influence of temperature, SO2 concentration and ammonia addition is discussed.

  20. Comparison of structural changes in skin and amnion tissue grafts for transplantation induced by gamma and electron beam irradiation for sterilization.

    PubMed

    Mrázová, H; Koller, J; Kubišová, K; Fujeríková, G; Klincová, E; Babál, P

    2016-06-01

    Sterilization is an important step in the preparation of biological material for transplantation. The aim of the study is to compare morphological changes in three types of biological tissues induced by different doses of gamma and electron beam radiation. Frozen biological tissues (porcine skin xenografts, human skin allografts and human amnion) were irradiated with different doses of gamma rays (12.5, 25, 35, 50 kGy) and electron beam (15, 25, 50 kGy). Not irradiated specimens served as controls. The tissue samples were then thawn and fixed in 10 % formalin, processed by routine paraffin technique and stained with hematoxylin and eosin, alcian blue at pH 2.5, orcein, periodic acid Schiff reaction, phosphotungstic acid hematoxylin, Sirius red and silver impregnation. The staining with hematoxylin and eosin showed vacuolar cytoplasmic changes of epidermal cells mainly in the samples of xenografts irradiated by the lowest doses of gamma and electron beam radiation. The staining with orcein revealed damage of fine elastic fibers in the xenograft dermis at the dose of 25 kGy of both radiation types. Disintegration of epithelial basement membrane, especially in the xenografts, was induced by the dose of 15 kGy of electron beam radiation. The silver impregnation disclosed nuclear chromatin condensation mainly in human amnion at the lowest doses of both radiation types and disintegration of the fine collagen fibers in the papillary dermis induced by the lowest dose of electron beam and by the higher doses of gamma radiation. Irradiation by both, gamma rays and the electron beam, causes similar changes on cells and extracellular matrix, with significant damage of the basement membrane and of the fine and elastic and collagen fibers in the papillary dermis, the last caused already by low dose electron beam radiation.

  1. Effect of Mercerization and Electron-Beam Irradiation on Mechanical Properties of High Density Polyethylene (HDPE) / Brazil Nut Pod Fiber (BNPF) Bio-Composites

    NASA Astrophysics Data System (ADS)

    Campos, Rejane D.; Sotenko, Maria; Hosur, Mahesh; Jeelani, Shaik; Díaz, Francisco R. V.; Moura, Esperidiana A. B.; Kirwan, Kerry; Seo, Emilia S. M.

    The use of natural fibers with polymeric resins has spread rapidly. In order to improve the mechanical properties of material, in this work, two variables were used: mercerization and electron beam irradiation. This paper describes the preparation and characterization of bio-composites that were prepared in two different routes using green high density polyethylene (HDPE) and Brazil nut pod fiber (BNPF): the first was to irradiate the composite with 150 kGy and the second was to irradiate the matrix with 15 kGy followed by composite preparation. In both cases mercerized and non-mercerized fibers were used. The irradiation process was carried out using a 1.5 MeV electron beam accelerator, at room temperature and in the presence of air. The material was characterized to evaluate the effect of treatment on mechanical properties of material.

  2. Effect of electron beam irradiation on thermal and mechanical properties of poly (lactic acid)/poly (ethylene-co-glycidyl methacrylate) blend

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish; Rao, T. Venkatappa; Chowdhury, S. Ray; Reddy, S. V. S. R.

    2017-06-01

    Physiochemical blend of Poly (lactic acid) (PLA)/Poly (ethylene-co-glycidyl methacrylate) (PEGMA) has been prepared by using twin-screw Micro compounder. The weight ratio of the blends was fixed at 80:20 (PLA: PEGMA). After that, the multipurpose test specimens -ASTM D638 of resulting blend and pristine PLA were prepared by injection moulding with mould temperature 32˚C. Furthermore, some test Specimens -ASTM D256 also prepared for notch impact test. The prepared samples were exposed to electron beam irradiation at different doses. These samples (un-irradiated and irradiated) were tested for mechanical and thermal properties. A detailed study is made by observing the improvement in the mechanical and thermal properties of the prepared blends with and without electron beam irradiation.

  3. Charging/discharge events in coated spacecraft polymers during electron beam irradiation in a scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Czeremuszkin, G.; Latrèche, M.; Wertheimer, M. R.

    2001-12-01

    Spacecraft, such as those operating in geosynchronous orbit (GEO), can be subjected to intense irradiation by charged particles, for example high-energy (e.g. 20 keV) electrons. The surfaces of dielectric materials (for example, polymers used as "thermal blankets") can therefore become potential sites for damaging electrostatic discharge (ESD) pulse events. We simulate these conditions by examining small specimens of three relevant polymers (polyimide, polyester and fluoropolymer), both bare and coated, in a scanning electron microscope (SEM). The coatings examined include commercial indium-tin oxide (ITO), and thin films of SiO 2 and a-Si:H deposited by plasma-enhanced chemical vapor deposition (PECVD). All coatings are found to greatly modify the observed ESD behavior, compared with that of the bare polymer counterparts. These observations are explained in terms of the model for ESD pulses proposed by Frederickson.

  4. Measurement of Space Charges in Dielectric Materials by Pulse Electro-acoustic Method after Irradiation by High-energy Electron Beam

    NASA Astrophysics Data System (ADS)

    Xiaogang, Qin; Kai, Li; Mayali; Xiaoquan, Zheng; Xiaodong, Liu

    2009-01-01

    Dielectric materials are widely used in space environment. When they are irradiated, charges will accumulate in the bulk and on the surface of the material, leading to pulse discharge events that can cause permanent changes in their physical and chemical structure. In this paper, a special method called PEA (pulse electro-acoustic) was used to measure and analyze the space charging of several dielectric materials after they have been irradiated by different high-energy electron beams.

  5. Structural, morphological and optical investigations on electron-beam irradiated PbF2-TeO2-B2O3-Eu2O3 glasses

    NASA Astrophysics Data System (ADS)

    Wagh, Akshatha; Petwal, Vikash; Dwivedi, Jishnu; Upadhyaya, V.; Raviprakash, Y.; Kamath, Sudha D.

    2016-09-01

    Combined structural, optical and morphological studies were carried out on Eu2O3 doped PbF2-TeO2-B2O3 glass samples, before and after being subjected to electron beam of energy 7.5 MeV. XRD confirmed the amorphous nature of the glasses even after 150 kGy electron beam irradiation. Densities of the irradiated samples showed slightly greater values when compared to their respective values before irradiation, which proved the increase in the compaction of the network. The intensities of the three prominent bands; B-O-B linkages, BO4 units and BO3 units of FT-IR spectra, of the titled glasses, showed slight decrease after electron beam irradiation. The decrement in the values of energy band gap and shift in cut-off wavelength towards red edge, proved the formation of color centers in the glass network after irradiation. The change in Hunter L values, through color measurement was a proof for the Farbe/color/absorption centers created in the glass sites after irradiation.

  6. The Effect of Electron Beam Irradiation in Environmental Scanning Transmission Electron Microscopy of Whole Cells in Liquid.

    PubMed

    Hermannsdörfer, Justus; Tinnemann, Verena; Peckys, Diana B; de Jonge, Niels

    2016-06-01

    Whole cells can be studied in their native liquid environment using electron microscopy, and unique information about the locations and stoichiometry of individual membrane proteins can be obtained from many cells thus taking cell heterogeneity into account. Of key importance for the further development of this microscopy technology is knowledge about the effect of electron beam radiation on the samples under investigation. We used environmental scanning electron microscopy (ESEM) with scanning transmission electron microscopy (STEM) detection to examine the effect of radiation for whole fixed COS7 fibroblasts in liquid. The main observation was the localization of nanoparticle labels attached to epidermal growth factor receptors (EGFRs). It was found that the relative distances between the labels remained mostly unchanged (<1.5%) for electron doses ranging from the undamaged native state at 10 e-/Å2 toward 103 e-/Å2. This dose range was sufficient to determine the EGFR locations with nanometer resolution and to distinguish between monomers and dimers. Various different forms of radiation damage became visible at higher doses, including severe dislocation, and the dissolution of labels.

  7. Nanoscale controlled Li-insertion reaction induced by scanning electron-beam irradiation in a Li4Ti5O12 electrode material for lithium-ion batteries.

    PubMed

    Kitta, Mitsunori; Kohyama, Masanori

    2017-05-10

    The development of a nanoscale battery reaction in an electrode material associated with in situ microscopic observation is significant to an understanding of the solid-state mechanism of a battery reaction. With a Li4Ti5O12 (LTO) crystal as the negative electrode of a Li-ion battery (LIB), we show that a nanoscale-controlled Li-insertion reaction can be produced by electron beam irradiation with scanning transmission electron microscopy (STEM). A selected area in a Li2O-coated thin LTO crystal was irradiated by the electron probe of STEM with a high beam intensity of 2.5 × 10(7) (electrons per nm(2)). Electron energy-loss spectroscopy (EELS) revealed that significant changes in the chemical feature occurred only in the high-dose irradiation area in the LTO specimen. The features of Li-K, Ti-L and O-K spectra in that area were completely equal to those of a Li7Ti5O12 (Li-LTO) phase, as an electrochemically Li-inserted LTO phase, in contrast to usual LTO-like spectra in the region surrounding the specimen. For a pristine LTO specimen without Li2O coating, no Li-insertion reaction was observed under the same irradiation conditions. The high-dose electron beam seems to induce the dissociation of Li2O, providing Li ions and electrons, and the rapid and directional growth of a Li-LTO phase along the electron beam in the LTO specimen, forming a nanoscale steep interface with the surrounding LTO phase. The present phenomenon is a new type of electron beam assisted chemical reaction in a solid state, and could have a large impact on the science and technology of battery materials.

  8. Three-dimensional indium distribution in electron-beam irradiated multiple quantum wells of blue-emitting InGaN/GaN devices

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Young; Seol, Jae-Bok; Kwak, Chan-Min; Park, Chan-Gyung

    2016-03-01

    The compositional distribution of In atoms in InGaN/GaN multiple quantum wells is considered as one of the candidates for carrier localization center, which enhances the efficiency of the light-emitting diodes. However, two challenging issues exist in this research area. First, an inhomogeneous In distribution is initially formed by spinodal decomposition during device fabrication as revealed by transmission electron microscopy. Second, electron-beam irradiation during microscopy causes the compositional inhomogeneity of In to appear as a damage contrast. Here, a systematic approach was proposed in this study: Electron-beam with current density ranging from 0 to 20.9 A/cm2 was initially exposed to the surface regions during microscopy. Then, the electron-beam irradiated regions at the tip surface were further removed, and finally, atom probe tomography was performed to run the samples without beam-induced damage and to evaluate the existence of local inhomegenity of In atoms. We proved that after eliminating the electron-beam induced damage regions, no evidence of In clustering was observed in the blue-emitting InGaN/GaN devices. In addition, it is concluded that the electron-beam induced localization of In atoms is a surface-related phenomenon, and hence spinodal decomposition, which is typically responsible for such In clustering, is negligible for biaxially strained blue-emitting InGaN/GaN devices.

  9. Three-dimensional indium distribution in electron-beam irradiated multiple quantum wells of blue-emitting InGaN/GaN devices

    SciTech Connect

    Jung, Woo-Young; Seol, Jae-Bok Kwak, Chan-Min; Park, Chan-Gyung

    2016-03-14

    The compositional distribution of In atoms in InGaN/GaN multiple quantum wells is considered as one of the candidates for carrier localization center, which enhances the efficiency of the light-emitting diodes. However, two challenging issues exist in this research area. First, an inhomogeneous In distribution is initially formed by spinodal decomposition during device fabrication as revealed by transmission electron microscopy. Second, electron-beam irradiation during microscopy causes the compositional inhomogeneity of In to appear as a damage contrast. Here, a systematic approach was proposed in this study: Electron-beam with current density ranging from 0 to 20.9 A/cm{sup 2} was initially exposed to the surface regions during microscopy. Then, the electron-beam irradiated regions at the tip surface were further removed, and finally, atom probe tomography was performed to run the samples without beam-induced damage and to evaluate the existence of local inhomegenity of In atoms. We proved that after eliminating the electron-beam induced damage regions, no evidence of In clustering was observed in the blue-emitting InGaN/GaN devices. In addition, it is concluded that the electron-beam induced localization of In atoms is a surface-related phenomenon, and hence spinodal decomposition, which is typically responsible for such In clustering, is negligible for biaxially strained blue-emitting InGaN/GaN devices.

  10. Effect of gamma and electron beam irradiation on the physico-chemical and nutritional properties of mushrooms: a review.

    PubMed

    Fernandes, Ângela; Antonio, Amilcar L; Oliveira, M Beatriz P P; Martins, Anabela; Ferreira, Isabel C F R

    2012-11-15

    The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. Thus, prolonging postharvest storage, while preserving their quality, would benefit the mushroom industry as well as consumers. There has been extensive research on finding the most appropriate technology for mushrooms preservation. Gamma, electron-beam and UV irradiation have been shown to be potential tools in extending the postharvest shelf-life of fresh mushrooms. Studies evaluating the effects of ionizing radiation are available mainly in cultivated species such as Agaricus bisporus, Lentinus edodes and Pleurotus ostreatus. This review comprises a comprehensive study of the effects of irradiation on physico-chemical parameters (weight, colour, texture and pH), chemical compounds including nutrients (proteins, sugars and vitamins) and non-nutrients (phenolics, flavonoids and flavour compounds), and on biochemical parameters such as enzymatic activity of mushrooms for different species and from different regions of the world. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Impact of electron-beam irradiation on free-volume related microstructural properties of PVA:NaBr polymer composites

    NASA Astrophysics Data System (ADS)

    Ismayil; Vasachar, Ravindrachary; Bhajantri, Rajashekhar F.; Dhola, Praveena S.; Sanjeev, Ganesh

    2015-01-01

    Sodium Bromide doped Poly(vinyl alcohol) (PVA:NaBr, 80:20) polymer composite films were prepared using a solution casting method. These films were subjected to 8 MeV electron beam radiation at a dose of up to 300 kGy in air at room temperature. The free volume related microstructural and electrical properties of these irradiated films were studied using various characterization methods, such as positron annihilation lifetime spectroscopy (PALS) and AC & DC conductivity measurement techniques. The variations in the positron lifetime data indicate that the free-volume related properties of the doped polymer are affected by irradiation. From the results, it is found that at lower doses, a cross-linking network provides hopping sites for Na+ ions, and at higher doses, the chain-scission process facilitates ionic transport through segmental motion. Thus, the free volume around the polymer chain leads to mobility of the ions as well as the polymer segments and hence contributes to the enhancement of conductivity.

  12. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    SciTech Connect

    Lucero, J. F.; Rojas, J. I.

    2016-07-07

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  13. Influence of electron beam irradiation on nonlinear optical properties of Al doped ZnO thin films for optoelectronic device applications in the cw laser regime

    NASA Astrophysics Data System (ADS)

    Antony, Albin; Pramodini, S.; Poornesh, P.; Kityk, I. V.; Fedorchuk, A. O.; Sanjeev, Ganesh

    2016-12-01

    We present the studies on third-order nonlinear optical properties of Al doped ZnO thin films irradiated with electron beam at different dose rate. Al doped ZnO thin films were deposited on a glass substrate by spray pyrolysis deposition technique. The thin films were irradiated using the 8 MeV electron beam from microtron ranging from 1 kG y to 5 kG y. Nonlinear optical studies were carried out by employing the single beam Z-scan technique to determine the sign and magnitude of absorptive and refractive nonlinearities of the irradiated thin films. Continuous wave He-Ne laser operating at 633 nm was used as source of excitation. The open aperture Z-scan measurements indicated the sample displays reverse saturable absorption (RSA) process. The negative sign of the nonlinear refractive index n2 was noted from the closed aperture Z-scan measurements indicates, the films exhibit self-defocusing property due to thermal nonlinearity. The third-order nonlinear optical susceptibility χ(3) varies from 8.17 × 10-5 esu to 1.39 × 10-3 esu with increase in electron beam irradiation. The present study reveals that the irradiation of electron beam leads to significant changes in the third-order optical nonlinearity. Al doped ZnO displays good optical power handling capability with optical clamping of about ∼5 mW. The irradiation study endorses that the Al doped ZnO under investigation is a promising candidate photonic device applications such as all-optical power limiting.

  14. Effect of food characteristics, storage conditions, and electron beam irradiation on active agent release from polyamide-coated LDPE films.

    PubMed

    Han, J; Castell-Perez, M E; Moreira, R G

    2008-03-01

    We investigated the effect of electron beam irradiation, storage conditions, and model food pH on the release characteristics of trans-cinnamaldehyde incorporated into polyamide-coated low-density polyethylene (LDPE) films. Active agent release rate on irradiated films (up to 20.0 kGy) decreased by 69% compared with the nonirradiated controls, from 0.252 to 0.086 microg/mL/h. Storage temperature (4, 21, and 35 degrees C) and pH (4, 7, and 10) of the food simulant solutions (10% aqueous ethanol) affected the release rate of trans-cinnamaldehyde. As expected, antimicrobial release rate decreased to 0.013 microg/mL/h at the refrigerated temperature (4 degrees C) compared to the higher temperatures (0.029 and 0.035 microg/mL/h at 21 and 35 degrees C). The fastest release rate occurred when exposed to the acidic food simulant solution (pH 4). In aqueous solution, trans-cinnamaldehyde was highly unstable to ionizing radiation, with loss in concentration from 24.50 to 1.36 microg/mL after exposure to 2.0 kGy. Fourier transform infrared (FTIR) analysis revealed that exposure to ionizing radiation up to 10.0 kGy did not affect the structural conformation of LDPE/polyamide films and the trans-cinnamaldehyde in the films, though it induced changes in the functional group of trans-cinnamaldehyde when dose increased up to 20.0 kGy. Studies with a radiation-stable compound (naphthalene) showed that ionizing radiation induced the crosslinking in polymer networks of LDPE/polyamide film and caused slow and gradual release of the compound. This study demonstrated that irradiation serves as a controlling factor for release of active compounds, with potential applications in the development of antimicrobial packaging systems.

  15. Relativistic electron beam generator

    DOEpatents

    Mooney, L.J.; Hyatt, H.M.

    1975-11-11

    A relativistic electron beam generator for laser media excitation is described. The device employs a diode type relativistic electron beam source having a cathode shape which provides a rectangular output beam with uniform current density.

  16. Short communication: Survival of Mycobacterium avium ssp. paratuberculosis in tissues of cows following low-dose exposure to electron beam irradiation.

    PubMed

    Bode, John F; Thoen, Charles O

    2016-08-01

    This investigation was designed to determine the effects of low-dose electron beam irradiation on the survival of Mycobacterium avium ssp. paratuberculosis in tissue samples collected at necropsy from clinically affected cows. Mycobacterium avium ssp. paratuberculosis was isolated from the ileum and ileocecal valve of one cow and from the ileum of another cow irradiated at 4.0 kGy, but was not isolated from the ileum, ileocecal valve, or mesenteric lymph node of 11 other cows irradiated at 4 kGy.

  17. Improved crystallinity and dynamic mechanical properties of reclaimed waste tire rubber/EVA blends under the influence of electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Ramarad, Suganti; Ratnam, Chantara T.; Khalid, Mohammad; Chuah, Abdullah Luqman; Hanson, Svenja

    2017-01-01

    Dependence on automobiles has led to a huge amount of waste tires produced annually around the globe. In this study, the feasibility of recycling these waste tires by blending reclaimed waste tire rubber (RTR) with poly(ethylene-co-vinyl acetate) (EVA) and electron beam irradiation was studied. The RTR/EVA blends containing 100-0 wt% of RTR were prepared in the internal mixer followed by electron beam (EB) irradiation with doses ranging from 50 to 200 kGy. The processing torques, calorimetric and dynamic mechanical properties of the blends were studied. Blends were found to have lower processing torque indicating easier processability of RTR/EVA blends compared to EVA. RTR domains were found to be dispersed in EVA matrix, whereas, irradiation improved the dispersion of RTR into smaller domains in EVA matrix. Results showed the addition of EVA improves the efficiency of irradiation induced crosslink formation and dynamic mechanical properties of the blends at the expense of the calorimetric properties. Storage and loss modulus of 50 wt% RTR blend was higher than RTR and EVA, suggesting partial miscibility of the blend. Whereas, electron beam irradiation improved the calorimetric properties and dynamic mechanical properties of the blends through redistribution of RTR in smaller domain sizes within EVA.

  18. Oxygen-Content-Controllable Graphene Oxide from Electron-Beam-Irradiated Graphite: Synthesis, Characterization, and Removal of Aqueous Lead [Pb(II)].

    PubMed

    Bai, Jing; Sun, Huimin; Yin, Xiaojie; Yin, Xianqiang; Wang, Shengsen; Creamer, Anne Elise; Xu, Lijun; Qin, Zhi; He, Feng; Gao, Bin

    2016-09-28

    A high-energy electron beam was applied to irradiate graphite for the preparation of graphene oxide (GO) with a controllable oxygen content. The obtained GO sheets were analyzed with various characterization tools. The results revealed that the oxygen-containing groups of GO increased with increasing irradiation dosages. Hence, oxygen-content-controllable synthesis of GO can be realized by changing the irradiation dosages. The GO sheets with different irradiation dosages were then used to adsorb aqueous Pb(II). The effects of contact time, pH, initial lead ion concentration, and ionic strength on Pb(II) sorption onto different GO sheets were examined. The sorption process was found to be very fast (completed within 20 min) at pH 5.0. Except ionic strength, which showed no/little effect on lead sorption, the other factors affected the sorption of aqueous Pb(II) onto GO. The maximum Pb(II) sorption capacities of GO increased with irradiation dosages, confirming that electron-beam irradiation was an effective way to increase the oxygen content of GO. These results suggested that irradiated GO with a controllable oxygen content is a promising nanomaterial for environmental cleanup, particularly for the treatment of cationic metal ions, such as Pb(II).

  19. Polymerization of room-temperature ionic liquid monomers by electron beam irradiation with the aim of fabricating three-dimensional micropolymer/nanopolymer structures.

    PubMed

    Minamimoto, H; Irie, H; Uematsu, T; Tsuda, T; Imanishi, A; Seki, S; Kuwabata, S

    2015-04-14

    A novel method for fabricating microsized and nanosized polymer structures from a room-temperature ionic liquid (RTIL) on a Si substrate was developed by the patterned irradiation of an electron beam (EB). An extremely low vapor pressure of the RTIL, 1-allyl-3-ethylimidazolium bis((trifluoromethane)sulfonyl)amide, allows it to be introduced into the high-vacuum chamber of an electron beam apparatus to conduct a radiation-induced polymerization in the nanoregion. We prepared various three-dimensional (3D) micro/nanopolymer structures having high aspect ratios of up to 5 with a resolution of sub-100 nm. In addition, the effects of the irradiation dose and beam current on the physicochemical properties of the deposited polymers were investigated by recording the FT-IR spectra and Young's modulus. Interestingly, the overall shapes of the obtained structures were different from those prepared in our recent study using a focused ion beam (FIB) even if the samples were irradiated in a similar manner. This may be due to the different transmission between the two types of beams as discussed on the basis of the theoretical calculations of the quantum beam trajectories. Perceptions obtained in this study provide facile preparation procedures for the micro/nanostructures.

  20. Electron Beam Technology and Other Irradiation Technology Applications in the Food Industry.

    PubMed

    Pillai, Suresh D; Shayanfar, Shima

    2017-02-01

    Food irradiation is over 100 years old, with the original patent for X-ray treatment of foods being issued in early 1905, 20 years after there discovery by W. C. Roentgen in 1885. Since then, food irradiation technology has become one of the most extensively studied food processing technologies in the history of mankind. Unfortunately, it is the one of the most misunderstood technologies with the result that there are rampant misunderstandings of the core technology, the ideal applications, and how to use it effectively to derive the maximum benefits. There are a number of books, book chapters, and review articles that provide overviews of this technology [25, 32, 36, 39]. Over the last decade or so, the technology has come into greater focus because many of the other pathogen intervention technologies have been unable to provide sustainable solutions on how to address pathogen contamination in foods. The uniqueness of food irradiation is that this technology is a non-thermal food processing technology, which unto itself is a clear high-value differentiator from other competing technologies.

  1. Compatibilization of immiscible poly(lactic acid)/poly(ɛ-caprolactone) blend through electron-beam irradiation with the addition of a compatibilizing agent

    NASA Astrophysics Data System (ADS)

    Shin, Boo Young; Han, Do Hung

    2013-02-01

    The aim of this study was to compatibilize immiscible poly(lactic acid) (PLA)/poly(ɛ-caprolactone) (PCL) blend by using electron-beam radiation method with the addition of a compatibilizing agent. Glycidyl methacrylate (GMA) was chosen as the compatibilizing agent, in the expectation that the GMA plays a role as a monomeric compatibilizer and a reactive agent at the interface between the PLA and the PCL phases. Compatibilization process has been investigated through the melt mixing of the PLA/PCL and the GMA by using a twin-screw extruder and the exposure of the PLA/PCL/GMA mixture to electron-beam radiation at room temperature. The melt mixing process was performed to locate the GMA at the interface, thereby expecting a finer morphology due to the GMA as the monomeric plasticizer. The exposure process was carried out to induce definite interfacial adhesion at the interface through electron-beam initiated cross-copolymerization by the medium of the GMA as the reactive agent. To investigate the results of this compatibilization strategy, the morphological, mechanical, and rheological properties of the blend were analyzed. The morphological study clearly showed the reduced particle size of dispersed PCL domains and significantly improved interfacial adhesion by the electron-beam irradiation with the addition of the GMA. The stress-strain curves of the blends irradiated at less than 20 kGy showed the typical characteristics of ductile materials. The tensile properties of the blend were strongly affected by the dose of irradiation.

  2. Electron beam focusing system

    SciTech Connect

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  3. Color change of tourmaline by heat treatment and electron beam irradiation: UV-Visible, EPR, and Mid-IR spectroscopic analyses

    NASA Astrophysics Data System (ADS)

    Maneewong, Apichate; Seong, Baek Seok; Shin, Eun Joo; Kim, Jeong Seog; Kajornrith, Varavuth

    2016-01-01

    The color of pink tourmaline gemstone changed to colorless when heating at temperature of 600 °C in air. This colorless tourmaline recovered its pink color when irradiated with an electron beam (e-beam) of 800 kGy. The origin of the color change was investigated in three types of tourmaline gemstones, two pink are from Afghanistan and one green are from Nigeria, by using Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), Electron paramagnetic resonance (EPR), and Energy Dispersive X-ray Fluorescence (EDXRF). The UV-Vis absorption spectrum of the pink tourmaline with higher Mn concentration (T2, 0.24 wt%) showed characteristic absorption peaks originating from the Mn3+ color center: two absorption bands centered at wavelength of 396 and 520 nm, respectively. Both absorption bands disappeared when heated in air at 600 °C and then reappeared when irradiated with an e-beam at 800 kGy. EPR T2 spectra showed that the color change was related to the valence change of Mn3+ to Mn2+ and vice versa. The pink tourmaline of lower MnO content (T1, 0.08 wt%) also became colorless when heated, but the color was not recovered when the gemstone underwent e-beam irradiation. Instead, a yellow color was obtained. UV-Vis and FTIR spectra indicated that this yellow color originated from a decomposition of the hydroxyl group (-OH) into O- and Ho by the e-beam irradiation. Green tourmaline did not show any color change with either heat treatment or e-beam irradiation.

  4. Combination of electron beam irradiation and thermal treatment to enhance the shelf-life of traditional Indian fermented food (Idli)

    NASA Astrophysics Data System (ADS)

    Mulmule, Manoj D.; Shimmy, Shankar M.; Bambole, Vaishali; Jamdar, Sahayog N.; Rawat, K. P.; Sarma, K. S. S.

    2017-02-01

    Idli, a steam-cooked breakfast food item consumed in India, is famous as a staple food for its spongy texture and unique fermented taste. Idli preparation is a time consuming process; although instant Idli pre-mixes as powder or batter are available in the market, they do not have the distinctive taste and aroma similar to the Idli prepared at home. Hence ready-to-eat (RTE) form of this food is in demand. Therefore, an attempt was made to prepare RTE Idli bearing similar taste as home-cooked Idli with an extended shelf-life of up to two months at an ambient temperature using Electron Beam Irradiation (EBI) at dosages 2.5 kGy, 5 kGy and 7.5 kGy and combination processing comprised of EBI dosage at 2.5 kGy and thermal treatment (80 °C for 20 min). The treated Idli's were microbiologically and sensorially evaluated at storage periods of zero day, 14 days, 30 days and 60 days. Idli's irradiated at 7.5 kGy and subjected to combination processing at 2.5 kGy and thermal treatment were shelf-stable for 60 days. 2.5 kGy and 5 kGy radiation dosages alone were not sufficient to preserve Idli samples for more than 14 days. Undesirable change in sensory properties of Idli was observed at an EBI dosage of 7.5 kGy. Sensory properties of combination processed Idli's were found to undergo minor change over the storage period. The present work suggests that lowest radiation dosage in combination with thermal treatment could be useful to achieve the extended shelf-life without considerably impairing the organoleptic quality of Ready-to-Eat Idli.

  5. Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations

    SciTech Connect

    Matsui, S. Mori, Y.; Nonaka, T.; Hattori, T.; Kasamatsu, Y.; Haraguchi, D.; Watanabe, Y.; Uchiyama, K.; Ishikawa, M.

    2016-05-15

    For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films and Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management.

  6. Radiolysis products and sensory properties of electron-beam-irradiated high-barrier food-packaging films containing a buried layer of recycled low-density polyethylene.

    PubMed

    Chytiri, S D; Badeka, A V; Riganakos, K A; Kontominas, M G

    2010-04-01

    The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food 'cold pasteurization'). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the 'functional barrier' properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.

  7. Structural and kinetic modification of aqueous hydroxypropylmethylcellulose (HPMC) induced by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Furusawa, Kazuya; Dobashi, Toshiaki; Morishita, Satoshi; Oyama, Mikio; Hashimoto, Tadashi; Shinyashiki, Naoki; Yagihara, Shin; Nagasawa, Naotsugu

    2005-08-01

    Aqueous solutions of 10 and 20 wt% hydroxypropylmethylcellulose (HPMC) were irradiated with different doses to make gel films. The gel fraction of the film increased sharply above a critical dose upon increase of the dose and then decreased gradually after passing a maximum. The scission/cross-linking ratio and the critical dose were determined with the aid of Charlesby-Rosiak equation as 0.52 and 9 kGy for the 10 wt% gel and 0.43 and 14 kGy for the 20 wt% gel, respectively. The gel fraction for the 20 wt% HPMC film was lower at low dose and higher at high dose than that for the 10 wt% film. The behavior of the swelling ratio of the gel film was just opposite to that of the gel fraction. The cross-linking density of the gel estimated from the Flory theory increased linearly with the irradiation dose at low dose, passed through a maximum around 100 and 160 kGy for 10% and 20% films, respectively, and decreased at high dose. These results suggest a competition of scission and cross-linking induced by the indirect effect of irradiation. Dielectric-relaxation measurements by time-domain reflectometry and RF impedance/material analyzer revealed two characteristic relaxations of chain motions around 100 MHz and of orientation of free water around 20 GHz. From the dose dependence of the dielectric-relaxation parameters determined by fitting to a combined equation of the Cole-Cole type and of the KWW type, a coupling of motions of HPMC molecules and water molecules was strongly suggested. The critical dose for gelation was coincident with the dose for the maximum of τ and the minimum of Δε together with the minimum of τ and the maximum of Δε, where τ and Δε denote the relaxation time and the relaxation strength for water molecular motion and τ and Δε the corresponding ones for HPMC molecular motion. The characteristic behavior is discussed in terms of an increase of the affinity between HPMC and water and the constrained molecular motion in the gel network.

  8. Changes in spectrochemical and catalytic properties of biopolymer anchored Cu(II) and Ni(II) catalysts by electron beam irradiation.

    PubMed

    Antony, R; Suja Pon Mini, P S; Theodore David Manickam, S; Sanjeev, Ganesh; Mitu, Liviu; Balakumar, S

    2015-01-01

    Chitosan (a biopolymer) anchored Cu(II) and Ni(II) Schiff base complexes, [M(OIAC)Cl2] (M: Cu/Ni and OIAC: ([2-oxo-1H-indol-3-ylidene]amino)chitosan) were electron beam irradiated by different doses (100 Gy, 1 kGy and 10 kGy). The electron beam has shown potential impact on biopolymer's support, in detail chain linking and chain scissoring, as evidenced by viscosity studies, FT-IR and X-ray diffraction spectroscopic techniques. Due to these structural changes, thermal properties of the complexes were found to be changed. The surface of these heterogeneous complexes was also effectually altered by electron beam. As a consequence, pores and holes were created as probed by SEM technique. The catalytic activity of both non-irradiated and irradiated complexes was investigated in the aerobic oxidation of cyclohexane using hydrogen peroxide oxidant. The catalytic ability of the complexes was enhanced significantly after irradiation as the result of surface changes. The reusability of the complexes was also greatly affected because of the structural variations in polymeric support. In terms of both better catalytic activity along with the reusability, 1 kGy is suggested as the best dose to attain adequate increase in catalytic activity and good reusability.

  9. Thirteen-week feeding study of thaumatin (a natural proteinaceous sweetener), sterilized by electron beam irradiation, in Sprague-Dawley rats.

    PubMed

    Hagiwara, A; Yoshino, H; Sano, M; Kawabe, M; Tamano, S; Sakaue, K; Nakamura, M; Tada, M; Imaida, K; Shirai, T

    2005-08-01

    This study was designed to evaluate and characterize any subchronic toxicity of thaumatin sterilized by electron beam irradiation (5.0 kGy) when administered at dietary levels of 0% (control), 0.3%, 1.0% and 3.0% to groups of 10 male and 10 female Crj: CD (SD) IGS rats for 13 weeks. Separate groups of both sexes received 3.0% non-irradiated thaumatin. There were no treatment-related clinical signs or adverse effects on the survival rate, body weight, food consumption, water consumption and urinalysis, ophthalmology, haematology, or blood biochemistry data. No treatment-related alterations in gross pathology or organ weights were found in any group. On histopathological examination, sporadic spontaneous lesions known to occur in this strain of rats were the only findings, with no specific relation to the test substance. Thus, the no-observed-adverse-effect-level (NOAEL) was judged to be a dietary level of at least 3.0% (2502 mg/kg body weight/day for males, 2889 mg/kg body weight/day for females) for electron beam irradiated thaumatin under the present experimental conditions. It was concluded that electron beam-irradiation of thaumatin does not cause changes of any toxicological significance.

  10. Radiation-induced effects in the electron-beam irradiation of dietary flavonoids

    NASA Astrophysics Data System (ADS)

    Tamba, M.; Torreggiani, A.

    2004-09-01

    The harmful effects of oxidative processes in living organisms can be reduced by the dietary intake of flavonoids, a class of phenolic compounds ubiquitous in plants and widely found in a number of fruits, vegetables and beverages. Many fruits and vegetables are treated by irradiation to solve preservation problems and a radical-induced degradation of nutrients, including polyphenols, may occur. The free radical chemistry of two abundant flavonoids in food, catechin and quercetin, have been investigated by using pulse radiolysis technique. The central role of the phenoxyl-type radical and the strong influence of the state of protonation of the compounds on the pathway of formation and decay of the corresponding oxidized radicals has been evidenced from the spectral properties and chemical reactivity of the radicals derived from the attack of several oxidizing species ( ṡOH, N 3ṡ SO 4-ṡ).

  11. Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ready-to-bake cookie dough by gamma and electron beam irradiation.

    PubMed

    Jeong, Seul-Gi; Kang, Dong-Hyun

    2017-06-01

    This study was conducted to investigate the efficacy of gamma and electron beam irradiation to inactivate foodborne pathogens in ready-to-bake cookie dough and to determine the effect on quality by measuring color and texture changes. Cookie dough inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, or Listeria monocytogenes was subjected to gamma and electron beam irradiation, with doses ranging from 0 to 3 kGy. As the radiation dose increased, the inactivation effect increased among all tested pathogens. After 3.0 kGy of gamma and electron beam irradiation, numbers of inoculated pathogens were reduced to below the detection limit (1 log CFU/g). The D10-values of E. coli O157:H7, S. Typhimurium, and L. monocytogenes in cookie dough treated with gamma rays were 0.53, 0.51, and 0.71 kGy, respectively, which were similar to those treated by electron beam with the same dose. Based on the D10-value of pathogens in cookie dough, L. monocytogenes showed more resistance to both treatments than did E. coli O157:H7 and S. Typhimurium. Color values and textural characteristics of irradiated cookie dough were not significantly (P > 0.05) different from the control. These results suggest that irradiation can be applied to control pathogens in ready-to-bake cookie dough products without affecting quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Bacterial cellulose/acrylic acid hydrogel synthesized via electron beam irradiation: accelerated burn wound healing in an animal model.

    PubMed

    Mohamad, Najwa; Mohd Amin, Mohd Cairul Iqbal; Pandey, Manisha; Ahmad, Naveed; Rajab, Nor Fadilah

    2014-12-19

    Natural polymer-based hydrogels are of interest to health care professionals as wound dressings owing to their ability to absorb exudates and provide hydration for healing. The aims of this study were to develop and characterize bacterial cellulose/acrylic acid (BC/AA) hydrogels synthesized by electron beam irradiation and investigate its wound healing potential in an animal model. The BC/AA hydrogels were characterized by SEM, tensile strength, water absorptivity, and water vapor transmission rate (WVTR). The cytotoxicity of the hydrogels was investigated in L929 cells. Skin irritation and wound healing properties were evaluated in Sprague-Dawley rats. BC/AA hydrogels had a macroporous network structure, high swelling ratio (4000-6000% at 24h), and high WVTR (2175-2280 g/m(2)/day). The hydrogels were non-toxic in the cell viability assay. In vivo experiments indicated that hydrogels promoted faster wound-healing, enhanced epithelialization, and accelerated fibroblast proliferation compared to that in the control group. These results suggest that BC/AA hydrogels are promising materials for burn dressings.

  13. Degradation and acute toxicity removal of the antidepressant Fluoxetine (Prozac(®)) in aqueous systems by electron beam irradiation.

    PubMed

    Silva, Vanessa Honda Ogihara; Dos Santos Batista, Ana Paula; Silva Costa Teixeira, Antonio Carlos; Borrely, Sueli Ivone

    2016-06-01

    Electron beam irradiation (EBI) has been considered an advanced technology for the treatment of water and wastewater, whereas very few previous investigations reported its use for removing pharmaceutical pollutants. In this study, the degradation of fluoxetine (FLX), an antidepressant marketed as Prozac(®), was investigated by using EBI at FLX initial concentration of 19.4 ± 0.2 mg L(-1). More than 90 % FLX degradation was achieved at 0.5 kGy, with FLX below the detection limit (0.012 mg L(-1)) at doses higher than 2.5 kGy. The elucidation of organic byproducts performed using direct injection mass spectrometry, along with the results of ion chromatography, indicated hydroxylation of FLX molecules with release of fluoride and nitrate anions. Nevertheless, about 80 % of the total organic carbon concentration remained even for 7.5 kGy or higher doses. The decreases in acute toxicity achieved 86.8 and 9.6 % for Daphnia similis and Vibrio fischeri after EBI exposure at 5 kGy, respectively. These results suggest that EBI could be an alternative to eliminate FLX and to decrease residual toxicity from wastewater generated in pharmaceutical formulation facilities, although further investigation is needed for correlating the FLX degradation mechanism with the toxicity results.

  14. Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

    NASA Astrophysics Data System (ADS)

    Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

    2017-01-01

    In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

  15. Effect of oxidant addition on the elimination of 2-naphthalenesulfonate in aqueous solutions by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Alkhuraiji, Turki S.; Karpel Vel Leitner, Nathalie

    2016-09-01

    Aromatic sulfonated compounds and naphthalene derivatives are major chemical compounds used in the industry. Electron beam irradiation of aqueous solutions of 2-naphthalenesulfonate (90 μM) was investigated under various experimental conditions. The results obtained demonstrate that the 2-NS concentration decreased dramatically on increasing the absorbed dose in the range 0-1000 Gy. The effectiveness of the radiolytic system was demonstrably enhanced by the addition of oxidants (S2O82- or H2O2). 2-NS removal was higher with S2O82- than with H2O2. For the EB, EB/H2O2, and EB/S2O82- systems, the absorbed doses for 90% elimination of 2-NS (D90) were 700, 480, and 274 Gy, respectively. 2-NS is poorly mineralized by EB but more than 35% mineralization was reached for 15 kGy when oxidants (820 μM S2O82- or 935 μM H2O2) were added. In all systems, the mineralization yield was markedly higher when air (i.e. dissolved oxygen increase) was introduced between successive doses. For 50% 2-NS removal, seven sulfonated transformation products were identified using LC/MS analyses. For the highest absorbed doses the sulfonate group in 2-NS was converted to sulfate ions in the radiolytic systems.

  16. Microbial quality evaluation and effective decontamination of nutraceutically valued lotus seeds by electron beams and gamma irradiation

    NASA Astrophysics Data System (ADS)

    Bhat, Rajeev; Sridhar, K. R.; Karim, A. A.

    2010-09-01

    Lotus seeds are nutraceutically valued natural plant produce, which succumbs to microbial contamination, predominantly to toxigenic moulds. Results of the present study revealed seed coat portion to harbor higher proportion of microbial load, particularly fungi than cotyledon portion. Among the mycotoxins analyzed, aflatoxins (B 1, B 2, G 1 and G 2) were below detectable limits, while the seeds were devoid of Ochratoxin-A (OTA). Application of different doses of electron beam and gamma irradiation (0, 2.5, 5, 7.5, 10, 15 and 30 kGy) for decontamination purpose revealed significant dose-dependent decrease in the fungal contaminants ( P<0.05). However, the contaminant yeasts could survive up to 10 kGy dose, which could be completely eliminated at 15 kGy. From the results obtained, a dose range between 10 and 15 kGy is recommended for complete decontamination, as these doses have also been shown earlier to have minimal effects on nutritional and functional properties of lotus seeds.

  17. Patterning the mechanical properties of hydrogen silsesquioxane films using electron beam irradiation for application in mechano cell guidance

    PubMed Central

    Lanniel, Mathieu; Lu, Bingrui; Chen, Yifang; Allen, Stephanie; Buttery, Lee; Williams, Phil; Huq, Ejaz; Alexander, Morgan

    2011-01-01

    Hydrogen silsesquioxane (HSQ) is a material with the potential for studying the effect of surface stiffness on stem cell differentiation. Here, the effects of electron beam dose on the topography and the mechanical properties of HSQ obtained with or without trimethylamine (TMA) development are characterised by atomic force microscopy imaging and indentation. A correlation between the surface stiffness (uniform across the sample) and electron beam exposure is observed. Surface roughness of HSQ samples developed in TMA decreases exponentially with increasing electron beam exposure. Surface coating with plasma polymerised allylamine (ppAAm) leads to an overall decrease in stiffness values. However, the increase in surface stiffness with increasing electron beam exposure is still evident. The ppAAm coating is shown to facilitate human mesenchymal stem cell adhesion. PMID:21494321

  18. Studies on the storage effects and the peel structure of citrus irradiated by electron beam

    NASA Astrophysics Data System (ADS)

    Mei, Hua Fen

    1993-07-01

    When radiated with 0.5 kGy electron radiation, the peel structure kept normal, i.e. the waxy layer were thick, the oil cell and spongeous parenchyma cell arranged intensely, which results in plump fruits, lower rate of rot and weight loss during storage, and little bad influence on the flavour. The content of Vitamin C, total acid and total sugar were close to those of control.

  19. Electron-beam irradiation effects on phytochemical constituents and antioxidant capacity of pecan kernels [ Carya illinoinensis (Wangenh.) K. Koch] during storage.

    PubMed

    Villarreal-Lozoya, Jose E; Lombardini, Leonardo; Cisneros-Zevallos, Luis

    2009-11-25

    Pecans kernels (Kanza and Desirable cultivars) were irradiated with 0, 1.5, and 3.0 kGy using electron-beam (E-beam) irradiation and stored under accelerated conditions [40 degrees C and 55-60% relative humidity (RH)] for 134 days. Antioxidant capacity (AC) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays, phenolic (TP) and condensed tannin (CT) content, high-performance liquid chromatography (HPLC) phenolic profile, tocopherol content, peroxide value (PV), and fatty acid profiles were determined during storage. Irradiation decreased TP and CT with no major detrimental effects in AC. Phenolic profiles after hydrolysis were similar among treatments (e.g., gallic and ellagic acid, catechin, and epicatechin). Tocopherol content decreased with irradiation (>21 days), and PV increased at later stages (>55 days), with no change in fatty acid composition among treatments. Color lightness decreased, and a reddish brown hue developed during storage. A proposed mechanism of kernel oxidation is presented, describing the events taking place. In general, E-beam irradiation had slight effects on phytochemical constituents and could be considered a potential tool for pecan kernel decontamination.

  20. Electron Beam Freeform Fabrication

    NASA Image and Video Library

    Electron Beam Freeform Fabrication (EBF3) is a process by which NASA hopes to build metal parts in zero gravity environments. It's a layer-additive process that uses an electron beam and a solid wi...

  1. Effects of electron beam irradiation on the variability in survivor number and duration of lag phase of four food-borne organisms.

    PubMed

    Aguirre, Juan S; Rodríguez, María R; García de Fernando, Gonzalo D

    2011-10-03

    The effect of electron beam irradiation on microbial inactivation and duration of lag time of individual surviving cells of Listeria innocua, Enterococcus faecalis, Pseudomonas fluorescens and Salmonella Enteritidis has been studied. In addition, the data on variability in microbial inactivation and duration of lag phase for surviving microbes have been fitted by normal and gamma distributions, respectively. The standard deviations of survivor number and lag phase duration of individual cells were higher in irradiated batches than in non-irradiated ones. Furthermore, the more intense the irradiation treatment was, the higher the variability in both survivor number and duration of lag phase of survivors. These findings should be considered in predictive models of microbial inactivation, in risk assessment, and in adjusting preserving and/or storage conditions in the food industry.

  2. Electron beam irradiation induced compatibilization of immiscible polyethylene/ethylene vinyl acetate (PE/EVA) blends: Mechanical properties and morphology stability

    NASA Astrophysics Data System (ADS)

    Entezam, Mehdi; Aghjeh, Mir Karim Razavi; Ghaffari, Mehdi

    2017-02-01

    Gel content, mechanical properties and morphology of immiscible PE/EVA blends irradiated by high energy electron beam were studied. The results of gel content measurements showed that the capability of cross-linking of the blend samples increased with an increase of the EVA composition. Also, the gel content for most compositions of the blends displayed a positive deviation from the additive rule. The results of mechanical properties showed that the tensile strength and elongation at break of the samples increased and decreased, respectively, with irradiation dose. On the other hand, the mechanical properties of the irradiated blends also depicted a positive deviation from additive rule contrary to the un-irradiated blends. A synergistic effect observed for the mechanical properties improvement of the irradiated blends and it was attributed to the probable formation of the PE-graft-EVA copolymers at the interface of the blends during the irradiation process. A theoretical analysis revealed that irradiation induced synergistic effect was more significant for EVA-rich blends with weaker interfacial interaction as compared to PE-rich blends. The morphological analysis indicated that the blend morphology was not affected obviously, whereas it was stabilized by irradiation.

  3. The effect of electron beam irradiation on the mechanical properties of pineapple leaf fibre (PALF) reinforced high impact polystyrene (HIPS) composites

    NASA Astrophysics Data System (ADS)

    Siregar, J. P.; Sapuan, S. M.; Rahman, M. Z. A.; Zaman, H. M. D. K.

    2010-05-01

    The effects of electron beam irradiation on the mechanical properties of pineapple leaf fibre reinforced high impact polystyrene (HIPS) composites were studied. Two types of crosslinking agent that has been used in this study were trimethylolpropane triacrylate (TMPTA) and tripropylene gylcol diacrylate (TPGDA). A 50 wt.% of PALF was blended with HIPS and crosslinking agent using Brabender melt mixer at 165 °C. The composites were then irradiated using a 3 MeV electron beam accelerator with dosage of 0-100 kGy. The tensile strength, tensile modulus, flexural strength, flexural modulus, notched and unnotched impat and hardness of composites were measured and the effects of crosslinking agent were also compared.

  4. Free D-amino acids determination in ready-to-eat cooked ham irradiated with electron-beam by indirect chiral HPLC.

    PubMed

    Gil-Díaz, M; Santos-Delgado, M J; Rubio-Barroso, S; Polo-Díez, L M

    2009-05-01

    Potential racemization of L-amino acids (AA) in ready-to-eat (RTE) cooked ham after hygienization by electron-beam irradiation between 1 and 8kGy was studied. An indirect chiral method based on the derivatization reaction of AA with o-phthaldialdehyde and N-acetyl-L-cysteine followed by reversed-phase HPLC and fluorimetric detection was applied to detect ten enantiomeric pairs of free AA (Asp, Ser, Thr, Ala, Tyr, Val, Trp, Phe and Leu). Five of the D-AA were not found in any of the samples analyzed; the other five remaining D-AA (D-Asp, D-Ser, D-Ala, D-Val and D-Leu) were detected both in irradiated and non-irradiated cooked ham samples, their content being in the range 1.25-13.79μg/g. Although significant differences appeared for a few of the samples and doses, no positive correlation between the D-AA content and the irradiation doses was observed. Therefore, the electron-beam irradiation technique could be useful for sanitation of packed RTE cooked ham at doses allowed by WHO and EU, since it remains chemically safe to eat.

  5. Application of electron-beam irradiation on the production of salted and seasoned short-necked clam, Tapes Pilippinarum, for safe distribution

    NASA Astrophysics Data System (ADS)

    Kim, B.; Song, H. P.; Choe, J. H.; Jung, S.; Jang, A.; Kim, Y. J.; Jo, C.

    2009-07-01

    Salted and seasoned short-necked clam ( Tapes Philippinarum; SNC) and its major ingredients, red hot pepper powder, ginger, garlic and onion were irradiated at 0.5, 1, 2 and 5 kGy, respectively, and the microbiological and sensory quality were evaluated. The water activities of SNC and red pepper powder were 0.91 and 0.56, respectively, and others were higher than 0.97. The initial microbial populations of SNC were approximately 3.99, 4.38 and 2.22 log CFU/g for total aerobic bacteria, yeast and mold, and coliform bacteria. The highest contamination of total aerobic bacteria was detected from ground ginger among ingredients at 5.51 log CFU/g. Electron-beam irradiation (0, 0.5, 1, 2 and 5 kGy) significantly reduced the initial microbial level of SNC and its ingredients not only immediately after irradiation, but also during storage at 10 °C for 4 weeks ( p<0.05). There was no adverse change of sensory score except for the color of onion irradiated at 5 kGy, which results in a lower score than control. From the results electron-beam irradiation is a useful tool to enhance the storage stability and safe distribution of SNC.

  6. Influence of electron beam irradiation on electrical, structural, magnetic and thermal properties of Pr0.8Sr0.2MnO3 manganites

    NASA Astrophysics Data System (ADS)

    Christopher, Benedict; Rao, Ashok; Petwal, Vikash Chandra; Verma, Vijay Pal; Dwivedi, Jishnu; Lin, W. J.; Kuo, Y.-K.

    2016-12-01

    In this communication, the effect of electron beam (EB) irradiation on the structural, electrical transport and thermal properties of Pr0.8Sr0.2MnO3 manganites has been investigated. Rietveld refinement of XRD data reveals that all samples are single phased with orthorhombic distorted structure (Pbnm). It is observed that the orthorhombic deformation increases with EB dosage. The Mn-O-Mn bond angle is found to increase with increase in EB dosage, presumably due to strain induced by these irradiations. Analysis on the measured electrical resistivity data indicates that the small polaron hopping model is operative in the high temperature region for pristine as well as EB irradiated samples. The electrical resistivity in the entire temperature region has been successfully fitted with the phenomenological percolation model which is based on phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. The Seebeck coefficient (S) of the pristine as well as the irradiated samples exhibit positive values, indicating that holes is the dominant charge carriers. The analysis of Seebeck coefficient data confirms that the small polaron hopping mechanism governs the thermoelectric transport in the high temperature region. In addition, Seebeck coefficient data also is well fitted with the phenomenological percolation model. The behavior in thermal conductivity at the transition is ascribed to the local anharmonic distortions associated with small polarons. Specific heat measurement indicates that electron beam irradiation enhances the magnetic inhomogeneity of the system.

  7. Modification of the Structural-Phase State of the Surface Layer of a Cermet Composite Under Electron Beam Irradiation in Inert Gas Plasmas

    NASA Astrophysics Data System (ADS)

    Ovcharenko, V. E.; Ivanov, K. V.; Ivanov, Yu. F.; Mokhovikov, A. A.; Bao Hai, Yu.

    2017-04-01

    The results of investigation of characteristic features of modification of the structural-phase state of the surface layer of a TiC-(Ni-Cr) cermet composite under irradiation by a pulsed electron beam in the discharge plasma of inert gases with different atomic masses and ionization energies are presented. The effect of modification of the structural-phase state of the composite surface layer on its strength is analyzed under conditions of threepoint bending.

  8. Electron-Beam Irradiation Effect on Thermal and Mechanical Properties of Nylon-6 Nanocomposite Fibers Infused with Diamond and Diamond Coated Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Imam, Muhammad A.; Jeelani, Shaik; Rangari, Vijaya K.; Gome, Michelle G.; Moura, Esperidiana. A. B.

    2016-02-01

    Nylon-6 is an engineering plastic with excellent properties and processability, which are essential in several industrial applications. The addition of filler such as diamond (DN) and diamond coated carbon nanotubes (CNTs) to form molded composites may increase the range of Nylon-6 applications due to the resulting increase in strength. The effects of electron-beam irradiation on these thermoplastic nanocomposites are either increase in the cross-linking or causes chain scission. In this study, DN-coated CNTs were synthesized using the sonochemical technique in the presence of cationic surfactant cetyltrimethyl ammonium bromide (CTAB). The DN-coated CNTs nanoparticles and diamond nanoparticles were then introduced into Nylon-6 polymer through a melt extrusion process to form nanocomposite fibers. They were further tested for their mechanical (Tensile) and thermal properties (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)). These composites were further exposed to the electron-beam (160kGy, 132kGy and 99kGy) irradiation using a 1.5MeV electron-beam accelerator, at room temperature, in the presence of air and tested for their thermal and mechanical properties. The best ultimate tensile strength was found to be 690MPa and 864MPa irradiated at 132 for DN/CNTs/Nylon-6 and Diamond/Nylon-6 nanocomposite fiber as compared to 346MPa and 321MPa for DN/CNTs/Nylon-6 and Diamond/Nylon-6 nanocomposite fiber without irradiation. The neat Nylon-6 tensile strength was 240MPa. These results are consistent with the activation energy calculated from TGA graphs. DSC analysis result shows that the slight increase in glass transition temperature (Tg) and decrease in melting temperature (Tm) which was expected from high electron-beam radiation dose.

  9. Annealing shallow Si/SiO2 interface traps in electron-beam irradiated high-mobility metal-oxide-silicon transistors

    NASA Astrophysics Data System (ADS)

    Kim, J.-S.; Tyryshkin, A. M.; Lyon, S. A.

    2017-03-01

    Electron-beam (e-beam) lithography is commonly used in fabricating metal-oxide-silicon (MOS) quantum devices but creates defects at the Si/SiO2 interface. Here, we show that a forming gas anneal is effective at removing shallow defects (≤4 meV below the conduction band edge) created by an e-beam exposure by measuring the density of shallow electron traps in two sets of high-mobility MOS field-effect transistors. One set was irradiated with an electron-beam (10 keV, 40 μC/cm2) and was subsequently annealed in forming gas while the other set remained unexposed. Low temperature (335 mK) transport measurements indicate that the forming gas anneal recovers the e-beam exposed sample's peak mobility (14 000 cm2/Vs) to within a factor of two of the unexposed sample's mobility (23 000 cm2/Vs). Using electron spin resonance (ESR) to measure the density of shallow traps, we find that the two sets of devices are nearly identical, indicating the forming gas anneal is sufficient to anneal out shallow defects generated by the e-beam exposure. Fitting the two sets of devices' transport data to a percolation transition model, we extract a T = 0 percolation threshold density in quantitative agreement with our lowest temperature ESR-measured trap densities.

  10. Effect of crossed beams irradiation on parametric instabilities

    SciTech Connect

    Labaune, C., Ecole Polytechnique, France

    1998-04-27

    Modification of the growth of scattering processes in the case of multiple beam irradiation compared to single beam irradiation has been investigated in a preformed plasma using Thomson scattrering of a short wavelength probe beam, and spectral and temporal analysis of reflected and transmitted light. First observations of the reduction of the amplitude of ion acoustic waves associated with stimulated Brillouin scattering, amplification of the amplitude of electron plasma waves associated with stimulated Raman scattering, and transfer of energy between crqssing beams with same frequency in a flowing plasma under crossed beam irradiation are reported.

  11. Effects of gamma ray and electron beam irradiation on reduction of microbial load and antioxidant properties of Chum-Hed-Thet (Cassia alata (L.) Roxb.)

    NASA Astrophysics Data System (ADS)

    Prakhongsil, P.; Pewlong, W.; Sajjabut, S.; Chookaew, S.

    2017-06-01

    Considering the growing demands of herbal medicines, Cassia alata (L.) Roxb. has been reported to have various phytochemical activities. It has also been called in Thai as Chum-Hed-Thet. In this study, C. alata (L.) Roxb. powder were exposed to gamma and electron beam irradiation at doses of 0, 5, 10, 15 and 20 kGy. At the dose of 10 kGy, both of gamma and electron beam irradiation were sufficient in reducing microbial load of irradiated samples as specified in Thai pharmacopoeia (2005). These include the total aerobic microbial count of < 5.0x105 CFU/g, total fungi count of < 5.0x104 CFU/g, bile tolerant gram negative bacteria of < 104 (per g). In addition, pathogenic Clostridium spp. (per 10 g), Salmonella spp. (per 10 g), S. aureus (per 1g) and E.coli (per 1g) were absence. In terms of the bioactive molecules, the total phenolic content, DPPH free radical scavenging activity and ferric reducing antioxidant potential of unirradiated and irradiated samples were 19.32-22.44 mg gallic acid equivalent/g, 5.20-7.82 mg ascorbic acid equivalent/g and 69.46-82.06 μmol FeSO4/g, respectively. However, there were no significant differences between unirradiated and irradiated samples (p>0.05). Therefore, both of radiation by gamma ray or electron beam at 10 kGy was sufficient in elimination of microbial flora and did not significantly affected the total phenolic content and antioxidant activities of C. alata (L.) Roxb.

  12. Fungal decontamination and enhancement of shelf life of edible split beans of wild legume Canavalia maritima by the electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Supriya, P.; Sridhar, K. R.; Ganesh, S.

    2014-03-01

    Ripened split beans of the coastal sand dune wild legume Canavalia maritima serve as one of the traditional nutritional sources of the coastal dwellers in Southwest coast of India. Nine fungi were isolated from the unirradiated dry beans by plating on the potato dextrose agar medium. Toxigenic fungus Aspergillus niger showed the highest incidence (33-50%) followed by Aspergillus flavus (14-20%) and Penicillium chrysogenum (7-13%). Unirradiated dry beans and irradiated dry beans with electron beam doses 2.5, 5, 10 and 15 kGy were monitored for occurrence of fungal species and their incidence during 0, 3 and 6 months storage period under laboratory conditions. Irradiation resulted in dose-dependent decrease in fungal species (5-7, 4-6, 3-6 and 0 on irradiation at 0, 2.5, 5 and 10 or 15 kGy, respectively) as well as incidence (80-99, 19-46, 13-21 and 0%, respectively). Although aflatoxins (B1 and B2) were found below detectable level (<2 ng/g) in 0, 3 and 6 months stored unirradiated and irradiated beans (2.5 and 5 kGy), they were not present in beans irradiated with 10 and 15 kGy. In spite of occurrence of toxigenic fungus Aspergillus ochraceus in unirradiated and irradiated beans (2.5 and 5 kGy) stored for 3 and 6 months, the beans were devoid of ochratoxin-A. Electron beam irradiation dose 10 kGy could be recommended for fungal decontamination and improvement of shelf life of C. maritima ripened dry split beans.

  13. Study of the evolution of the atomic composition of thin NbN films under irradiation with mixed ion beams by methods of electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Dement'eva, M. M.; Prikhod'ko, K. E.; Gurovich, B. A.; Kutuzov, L. V.; Komarov, D. A.

    2016-11-01

    The variation in the atomic composition of ultrathin NbN films under irradiation by mixed ion beams to a doze of 4 dpa (for nitrogen) is experimentally studied by methods of electron energy loss spectroscopy with a transmission electron microscope in the transmission scan mode on cross-cut samples. The behavior of the substitution of nitrogen atoms by oxygen atoms has been established; it is characterized by changing the composition of the conducting part of the film from NbN to NbNO.

  14. Edible flowers of Viola tricolor L. as a new functional food: antioxidant activity, individual phenolics and effects of gamma and electron-beam irradiation.

    PubMed

    Koike, Amanda; Barreira, João C M; Barros, Lillian; Santos-Buelga, Celestino; Villavicencio, Anna L C H; Ferreira, Isabel C F R

    2015-07-15

    Edible flowers are used in food preparations, being also recognized for their beneficial effects on human health. Nevertheless, these species are highly perishable, and irradiation treatment might be applied to ensure food quality and increase their shelf life. Viola tricolor L. is a typical edible flower, with multiple applications and biological properties, mainly provided by the flavonoid content. In the present work, the phenolic compounds were analyzed by HPLC-DAD-ESI/MS, and the antioxidant activity was evaluated using biochemical assays. Linear discriminant analyses (LDA) were performed in order to compare the results obtained with flowers submitted to different irradiation doses and technologies (cobalt-60 and electron-beam). In general, irradiated samples (mostly with 1 kGy) showed the highest phenolic content and antioxidant activity. Furthermore, the significant differences observed in the LDA allow determination of which dose and/or technology is suitable to obtain flowers with higher antioxidant potential. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Post-focus expansion of ion beams for low fluence and large area MeV ion irradiation: Application to human brain tissue and electronics devices

    NASA Astrophysics Data System (ADS)

    Whitlow, Harry J.; Guibert, Edouard; Jeanneret, Patrick; Homsy, Alexandra; Roth, Joy; Krause, Sven; Roux, Adrien; Eggermann, Emmanuel; Stoppini, Luc

    2017-08-01

    Irradiation with ∼3 MeV proton fluences of 106-109 protons cm-2 have been applied to study the effects on human brain tissue corresponding to single-cell irradiation doses and doses received by electronic components in low-Earth orbit. The low fluence irradiations were carried out using a proton microbeam with the post-focus expansion of the beam; a method developed by the group of Breese [1]. It was found from electrophysiological measurements that the mean neuronal frequency of human brain tissue decreased to zero as the dose increased to 0-1050 Gy. Enhancement-mode MOSFET transistors exhibited a 10% reduction in threshold voltage for 2.7 MeV proton doses of 10 Gy while a NPN bipolar transistor required ∼800 Gy to reduce the hfe by 10%, which is consistent the expected values.

  16. Isothermal oxidation behaviour of thermal barrier coatings with CoCrAlY bond coat irradiated by high-current pulsed electron beam

    NASA Astrophysics Data System (ADS)

    Cai, Jie; Guan, Qingfeng; Hou, Xiuli; Wang, Zhiping; Su, Jingxin; Han, Zhiyong

    2014-10-01

    Thermal sprayed CoCrAlY bond coat irradiated by high-current pulsed electron beam (HCPEB) and thermal barrier coatings (TBCs) prepared with the irradiated bond coat and the ceramic top coat were investigated. The high temperature oxidation resistance of these specimens was tested at 1050 °C in air. Microstructure observations revealed that the original coarse surface of the as-sprayed bond coat was significantly changed as the interconnected bulged nodules with a compact appearance after HCPEB irradiation. Abundant Y-rich alumina particulates and very fine grains were dispersed on the irradiated surface. After high temperature oxidation test, the thermally grown oxide (TGO) in the initial TBCs grew rapidly and was comprised of two distinct layers: a large percentage of mixed oxides in the outer layer and a relatively small portion of Al2O3 in the inner layer. Severe local internal oxidation and extensive cracks in the TGO layer were discovered as well. Comparatively, the irradiated TBCs exhibited thinner TGO layer, slower TGO growth rate, and homogeneous TGO composition (primarily consisting of Al2O3). The results indicate that TBCs with the irradiated bond coat have a much higher oxidation resistance.

  17. Formation of the surface alloys by high-intensity pulsed electron beam irradiation of the coating/substrate system

    NASA Astrophysics Data System (ADS)

    Ivanov, Yu F.; Petrikova, E. A.; Teresov, A. D.; Krysina, O. V.; Rygina, M. E.

    2015-04-01

    The results of the analysis of the structure and properties of the surface layer of aluminum A7 subjected to alloying by the intense pulsed electron beam melting of the film / substrate system. Fold increase in strength and tribological properties of the modified surface layer due to the formation of submicro - nanoscale multiphase structure have been revealed.

  18. Photocarrier Radiometry for Noncontact Evaluation of Monocrystalline Silicon (c-Si) Solar Cell Irradiated by 1 MeV Electron Beams

    NASA Astrophysics Data System (ADS)

    Song, P.; Liu, J. Y.; Yuan, H. M.; Wang, F.; Wang, Y.

    2016-08-01

    In this paper, the monocrystalline silicon (c-Si) solar cell irradiated by 1 MeV electron beams was investigated using noncontact photocarrier radiometry (PCR). A theoretical 1D two-layer PCR model including the impedance effect of the p-n junction was used to characterize the transport properties (carrier lifetime, diffusion coefficient, and surface recombination velocities) of c-Si solar cells irradiated by 1 MeV electron beams with different fluences. The carrier transport parameters were derived by the best fit through PCR measurements. Furthermore, an Ev+0.56 eV trap was introduced into the band gap based on the minority carrier lifetime reduction. An I-V characteristic was obtained by both AFORS-HET simulation and experimental study, and the simulation results shows in good agreement with the experimental results. Moreover, the simulation and experiment results also indicate that the increase of fluences of electron beams results in the reduction of short-circuit current and open-circuit voltage.

  19. Effect of gamma radiation and accelerated electron beam on stable paramagnetic centers induction in bone mineral: influence of dose, irradiation temperature and bone defatting.

    PubMed

    Jastrzebska, Anna; Kaminski, Artur; Grazka, Ewelina; Marowska, Joanna; Sadlo, Jaroslaw; Gut, Grzegorz; Uhrynowska-Tyszkiewicz, Izabela

    2014-09-01

    Ionizing radiation has been found to induce stable defects in the crystalline lattice of bone mineral hydroxyapatite, defined as CO(2) (-) radical ions possessing spins. The purpose of our study was to evaluate CO(2) (-) radical ions induced in non-defatted or defatted human compact bone by gamma radiation (G) and accelerated electron beam (EB), applied with two doses at different temperatures. Moreover, the potential effect of free radical ion formation on mechanical parameters of compact bone, tested under compression in the previous studies, was evaluated. Bone rings from femoral shafts of six male donors (age 51 ± 3 years) were collected and assigned to sixteen experimental groups according to different processing methods (non-defatted or defatted), G and EB irradiation dose (25 or 35 kGy), and irradiation temperature [ambient temperature (AT) or dry ice (DI)]. Untreated group served as control. Following grinding under LN2 and lyophilization, CO(2) (-) radical ions in bone powder were measured by electron paramagnetic resonance spectrometry. We have found that irradiation of bone with G and EB induces formation of enormous amounts of CO(2) (-) radical ions, absent from native tissue. Free radical ion formation was dose-dependent when irradiation was performed at AT, and significantly lower in EB as compared to G-irradiated groups. In contrast, no marked effect of dose was observed when deep-frozen (DI) bone samples were irradiated with G or EB, and free radical ion numbers seemed to be slightly higher in EB-irradiated groups. Irradiation at AT induced much higher quantities of CO(2) (-) radical ions then on DI. That effect was more pronounced in G-irradiated bone specimens, probably due to longer exposure time. Similarly, bone defatting protective effect on free radical ion formation was found only in groups irradiated for several hours with gamma radiation at ambient temperature. Ambient irradiation temperature together with exposure time seem to be key

  20. Fabrication of nanoscale Ga balls via a Coulomb explosion of microscale silica-covered Ga balls by TEM electron-beam irradiation.

    PubMed

    Chen, Ying; Huang, Yanli; Liu, Nishuang; Su, Jun; Li, Luying; Gao, Yihua

    2015-06-23

    Nanoscale Ga particles down to 5 nm were fabricated by an explosion via an in situ electron-beam irradiation on microscale silica-covered Ga balls in a transmission electron microscope. The explosion is confirmed to be a Coulomb explosion because it occurs on the surface rather than in the whole body of the insulating silica-covered Ga micro-balls, and on the pure Ga nano-balls on the edge of carbon film. The ejected particles in the explosion increase their sizes with increasing irradiation time until the stop of the explosion, but decrease their sizes with increasing distance from the original ball. The Coulomb explosion suggests a novel method to fabricate nanoscale metal particles with low melting point.

  1. Selective area growth of Bernal bilayer epitaxial graphene on 4H-SiC (0001) substrate by electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Dharmaraj, P.; Jeganathan, K.; Parthiban, S.; Kwon, J. Y.; Gautam, S.; Chae, K. H.; Asokan, K.

    2014-11-01

    We report selective area growth of large area homogeneous Bernal stacked bilayer epitaxial graphene (BLEG) on 4H-SiC (0001) substrate by electron-beam irradiation. Sublimation of Si occurs by energetic electron irradiations on SiC surface via breaking of Si-C bonds in the localized region, which allows the selective growth of graphene. Raman measurements ensure the formation of homogeneous BLEG with weak compressive strain of -0.08%. The carrier mobility of large area BLEG is ˜5100 cm2 V-1 s-1 with a sheet carrier density of 2.2 × 1013 cm-2. Current-voltage measurements reveal that BLEG on 4H-SiC forms a Schottky junction with an operation at mA level. Our study reveals that the barrier height at the Schottky junction is low (˜0.58 eV) due to the Fermi-level pinning above the Dirac point.

  2. Formation of metal nanoparticles in MgF2, CaF2 and BaF2 crystals under the electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Bochkareva, Elizaveta S.; Sidorov, Alexander I.; Yurina, Uliana V.; Podsvirov, Oleg A.

    2017-07-01

    It is shown experimentally that electron beam action with electrons energies of 50 and 70 keV on MgF2, CaF2 and BaF2 crystals results in local formation in the crystal near-surface layer of Mg, Ca or Ba nanoparticles which possess plasmon resonance. In the case of MgF2 spheroidal nanoparticles are formed, in the cases of CaF2 and BaF2 - spherical. The formation of metal nanoparticles is confirmed by computer simulation in dipole quasistatic approximation. The dependence of absorption via electron irradiation dose is non-linear. It is caused by the increase of nanoparticles concentration and by the increase of nanoparticles sizes during irradiation. In the irradiated zones of MgF2 crystals, for irradiation doses less than 80 mC/cm2, the intense luminescence in a visible range appears. The practical application of fabricated composite materials for multilevel optical information recording is discussed.

  3. (Pulsed electron beam precharger)

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    This report discusses the following topics on electron beam guns: Precharger Modification; Installation of Charge vs. Radius Apparatus; High Concentration Aerosol Generation; and Data Acquisition and Analysis System.

  4. High electronic excitations and ion beam mixing effects in high energy ion irradiated Fe/Si multilayers

    SciTech Connect

    Bauer, P.; Dufour, C.; Jaouen, C.; Marchal, G.; Pacaud, J.; Grilhe, J.; Jousset, J.C.

    1997-01-01

    M{umlt o}ssbauer spectroscopy ({sup 57}Fe) shows evidence for mixing effects induced by electronic energy deposition in nanoscale Fe/Si multilayers irradiated with swift heavy ions. A decrease in the mixing efficiency with electronic stopping power is reported; a threshold is found, under which iron environment modifications no longer occur. The kinetics of Fe{endash}Si phase formation after irradiation suggests the existence of three regimes: (i) for high excitation levels, a magnetic amorphous phase is formed directly in the wake of the incoming ion and an almost complete mixing is reached at low fluence (10{sup 13} U/cm{sup 2}); (ii) for low excitation levels, a paramagnetic Si-rich amorphous phase is favored at the interface while crystalline iron subsists at high fluences; (iii) for intermediate excitation levels, saturation effects are observed and the formation rate of both magnetic and paramagnetic phases points to direct mixing in the ion wake but with a reduced track length in comparison to U irradiation. The measured interfacial mixing cross section induced by electronic energy deposition suggests that a thermal diffusion process is mainly involved in addition to damage creation. {copyright} {ital 1997 American Institute of Physics.}

  5. ELECTRON IRRADIATION OF SOLIDS

    DOEpatents

    Damask, A.C.

    1959-11-01

    A method is presented for altering physical properties of certain solids, such as enhancing the usefulness of solids, in which atomic interchange occurs through a vacancy mechanism, electron irradiation, and temperature control. In a centain class of metals, alloys, and semiconductors, diffusion or displacement of atoms occurs through a vacancy mechanism, i.e., an atom can only move when there exists a vacant atomic or lattice site in an adjacent position. In the process of the invention highenergy electron irradiation produces additional vacancies in a solid over those normally occurring at a given temperature and allows diffusion of the component atoms of the solid to proceed at temperatures at which it would not occur under thermal means alone in any reasonable length of time. The invention offers a precise way to increase the number of vacancies and thereby, to a controlled degree, change the physical properties of some materials, such as resistivity or hardness.

  6. Multispecimen dual-beam irradiation damage chamber

    SciTech Connect

    Packan, N.H.; Buhl, R.A.

    1980-06-01

    An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens, can be loaded into the ultrahigh vacuum chamber. Specimen holders are heated with individual electron guns, and the temperature of each specimen can be monitored during bombardment by an infrared pyrometer. Three different dose levels may be obtained during any single bombardment, and the heavy-ion flux on each of the nine specimens can be measured independently with only a brief interruption of the beam. The chamber has been in service for nearly three years, during which time approximately 250 bombardments have been successfully carried out. An appendix contains detailed procedures for operating the chamber.

  7. Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

    NASA Astrophysics Data System (ADS)

    Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E.; Jaczynski, Jacek

    2011-04-01

    Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D10-value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D10-values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D10-values for the ATCC strain were 0.59±0.031 and 0.46±0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D10-values increased (P<0.05) to 0.69±0.026 and 0.61±0.029 kGy, respectively. S. Typhimurium showed a trend (P>0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P<0.05) D10-values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

  8. Gamma and ion-beam irradiation of DNA: Free radical mechanisms, electron effects, and radiation chemical track structure

    NASA Astrophysics Data System (ADS)

    Sevilla, Michael D.; Becker, David; Kumar, Anil; Adhikary, Amitava

    2016-11-01

    The focus of our laboratory's investigation is to study the direct-type DNA damage mechanisms resulting from γ-ray and ion-beam radiation-induced free radical processes in DNA which lead to molecular damage important to cellular survival. This work compares the results of low LET (γ-) and high LET (ion-beam) radiation to develop a chemical track structure model for ion-beam radiation damage to DNA. Recent studies on protonation states of cytosine cation radicals in the N1-substituted cytosine derivatives in their ground state and 5-methylcytosine cation radicals in ground as well as in excited state are described. Our results exhibit a radical signature of excitations in 5-methylcytosine cation radical. Moreover, our recent theoretical studies elucidate the role of electron-induced reactions (low energy electrons (LEE), presolvated electrons (epre-), and aqueous (or, solvated) electrons (eaq-)). Finally DFT calculations of the ionization potentials of various sugar radicals show the relative reactivity of these species.

  9. Optical and structural study of GaN nanowires grown by catalyst-free molecular beam epitaxy. II. Sub-band-gap luminescence and electron irradiation effects

    SciTech Connect

    Robins, Lawrence H.; Bertness, Kris A.; Barker, Joy M.; Sanford, Norman A.; Schlager, John B.

    2007-06-01

    GaN nanowires with diameters of 50-250 nm, grown by catalyst-free molecular beam epitaxy, were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 to 297 K. Both as-grown samples and dispersions of the nanowires onto other substrates were examined. The properties of the near-band-edge PL and CL spectra were discussed in Part I of this study by [Robins et al. [L. H. Robins, K. A. Bertness, J. M. Barker, N. A. Sanford, and J. B. Schlager, J. Appl. Phys. 101,113505 (2007)]. Spectral features below the band gap, and the effect of extended electron irradiation on the CL, are discussed in Part II. The observed sub-band-gap PL and CL peaks are identified as phonon replicas of the free-exciton transitions, or excitons bound to structural defects or surface states. The defect-related peaks in the nanowires are correlated with luminescence lines previously reported in GaN films, denoted the Y lines [M. A. Reshchikov and H. Morkoc, J. Appl. Phys. 97, 061301 (2005)]. The CL was partially quenched by electron beam irradiation for an extended time; the quenching was stronger for the free and shallow-donor-bound exciton peaks than for the defect-related peaks. The quenching appeared to saturate at high irradiation dose (with final intensity {approx_equal}30% of initial intensity) and was reversible on thermal cycling to room temperature. The electron irradiation-induced quenching of the CL is ascribed to charge injection and trapping phenomena.

  10. Optical and structural study of GaN nanowires grown by catalyst-free molecular beam epitaxy. II. Sub-band-gap luminescence and electron irradiation effects

    NASA Astrophysics Data System (ADS)

    Robins, Lawrence H.; Bertness, Kris A.; Barker, Joy M.; Sanford, Norman A.; Schlager, John B.

    2007-06-01

    GaN nanowires with diameters of 50-250 nm, grown by catalyst-free molecular beam epitaxy, were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 to 297 K. Both as-grown samples and dispersions of the nanowires onto other substrates were examined. The properties of the near-band-edge PL and CL spectra were discussed in Part I of this study by [Robins et al. [L. H. Robins, K. A. Bertness, J. M. Barker, N. A. Sanford, and J. B. Schlager, J. Appl. Phys. 101,113505 (2007)]. Spectral features below the band gap, and the effect of extended electron irradiation on the CL, are discussed in Part II. The observed sub-band-gap PL and CL peaks are identified as phonon replicas of the free-exciton transitions, or excitons bound to structural defects or surface states. The defect-related peaks in the nanowires are correlated with luminescence lines previously reported in GaN films, denoted the Y lines [M. A. Reshchikov and H. Morkoc, J. Appl. Phys. 97, 061301 (2005)]. The CL was partially quenched by electron beam irradiation for an extended time; the quenching was stronger for the free and shallow-donor-bound exciton peaks than for the defect-related peaks. The quenching appeared to saturate at high irradiation dose (with final intensity ≈30% of initial intensity) and was reversible on thermal cycling to room temperature. The electron irradiation-induced quenching of the CL is ascribed to charge injection and trapping phenomena.

  11. Decoloration and mineralization of reactive dyes using electron beam irradiation, Part I: Effect of the dye structure, concentration and absorbed dose (single, binary and ternary systems)

    NASA Astrophysics Data System (ADS)

    Vahdat, Ali; Bahrami, S. Hajir; Arami, M.; Bahjat, A.; Tabakh, F.; Khairkhah, M.

    2012-07-01

    In this study, three different reactive dyes (C.I. Reactive Red 4, C.I. Reactive Blue 2 and C.I. Reactive Yellow 4) and their blend solutions were irradiated with 10 MeV electron beam. Effect of absorbed dose, dye structure and primary solution concentrations on the pH value changes, degree of decoloration and chemical oxygen demand (COD) removal of solutions were investigated. Results show that this method is effective in decomposition and decoloration of the dyes solutions. This method can be applied in mineralization of wastewater containing different dyes.

  12. Mechanical and thermal properties and morphological studies of 10 MeV electron beam irradiated LDPE/hydroxyapatite nano-composite

    NASA Astrophysics Data System (ADS)

    Soltani, Z.; Ziaie, F.; Ghaffari, M.; Afarideh, H.; Ehsani, M.

    2013-02-01

    In this work the nano-composite samples were prepared using the LDPE filled with different weight percentages of hydroxyapatite powder which was synthesized via hydrolysis method. The samples were subjected to irradiation under 10 MeV electron beam in 75-250 kGy doses. Mechanical and thermal properties as well as the morphology of the nano-composite samples were investigated and compared. The hot-set and swelling tests confirmed the radiation crosslinking induced in the polymer matrix especially between the matrix and reinforcement phase. The result indicates that the mechanical and thermal parameters are strongly dependent on the hydroxyapatite content in comparison to radiation.

  13. Atomic rearrangement of a sputtered MoS2 film from amorphous to a 2D layered structure by electron beam irradiation.

    PubMed

    Kim, Bong Ho; Gu, Hyun Ho; Yoon, Young Joon

    2017-06-20

    We synthesised a crystalline MoS2 film from as-sputtered amorphous film by applying an electron beam irradiation (EBI) process. A collimated electron beam (60 mm dia.) with an energy of 1 kV was irradiated for only 1 min to achieve crystallisation without an additional heating process. After the EBI process, we observed a two-dimensional layered structure of MoS2 about 4 nm thick and with a hexagonal atomic arrangement on the surface. A stoichiometric MoS2 film was confirmed to grow well on SiO2/Si substrates and include partial oxidation of Mo. In our experimental configuration, EBI on an atomically thin MoS2 layer stimulated the transformation from a thermodynamically unstable amorphous structure to a stable crystalline nature with a nanometer grain size. We employed a Monte Carlo simulation to calculate the penetration depth of electrons into the MoS2 film and investigated the atomic rearrangement of the amorphous MoS2 structure.

  14. Properties of Electron-Beam Irradiated CuInSe2 Layers by Multi-Step Sputtering Method.

    PubMed

    Kim, Chae-Woong; Kim, Jin Hyeok; Jeong, Chaehwan

    2015-10-01

    Typically, CuInSe2 (CIS) based thin films for photovoltaic devices are deposited by co-evaporation or by deposition of the metals, followed by treatment in a selenium environment. This article describes CIS films that are instead deposited by DC and RF magnetron sputtering from binary Cu2Se and In2Se3 targets without the supply of selenium. As a novel method, electron beam annealing was used for crystallization of Cu2Se/In2Se3 stacked precursors. The surface, cross-sectional morphology, and compositional ratio of CIS films were investigated to confirm the possibility in crystallization without any addition of selenium. Our work demonstrates that the e-beam annealing method can be a good candidate for the rapid crystallization of Cu-In-Se sputtered precursors.

  15. Electron Beam Influence on Microcrystalline Cellulose

    NASA Astrophysics Data System (ADS)

    Nemţanu, Monica R.; Minea, R.; Mitru, Ecaterina

    2007-04-01

    Cellulose is a natural raw material used in great quantity as stabilizer, tabletting agent, anti-caking agent, flavor carrier, etc. Due to its structure it has limited uses exhibiting some disadvantages in certain applications. Irradiation technique is frequently used to change the polymeric materials. The purpose of the work is to discuss the action of accelerated electron beams (e-beams) on microcrystalline cellulose. The results of the study showed that some properties of cellulose can be improved by electron beam treatment.

  16. Mycosis fungoides. Electron beam therapy.

    PubMed

    Spittle, M F

    1977-01-01

    The most effective treatment of late mycosis fungoides is total skin electron beam therapy. The beam at the Hammersmith Hospital in London has been adapted to treat these patients. Patients with advanced disease who have failed more conservative methods of treatment are irradiated. The electron beam is modified by the use of carbon and copper scatterers to produce an 80 percent depth dose at 5.5, 8 and 11.5 millimeters below the skin surface. The dose achieved in most patients is between 1500 rads and 2600 rads given in 10 to 13 treatments over 5-7 weeks. Recently the higher dose range has been employed and lithium flouride studies have shown that giving these doses from each of 4 fields, the dose achieved on the skin is approximately twice the given dose. The management of patients and the effects of treatment are discussed.

  17. Improvement of microbiological safety and sensorial quality of pork jerky by electron beam irradiation and by addition of onion peel extract and barbecue flavor

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Joo; Jung, Samooel; Yong, Hae In; Bae, Young Sik; Kang, Suk Nam; Kim, Il Suk; Jo, Cheorun

    2014-05-01

    The combined effects of electron-beam (EB) irradiation and addition of onion peel (OP) extract and barbecue flavor (BF) on inactivation of foodborne pathogens and the quality of pork jerky was investigated. Prepared pork jerky samples were irradiated (0, 1, 2, and 4 kGy) and stored for 2 month at 25 °C. The D10 values of Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium observed in the OP treated samples were 0.19, 0.18, and 0.19 kGy, whereas those in control were 0.25, 0.23, and 0.20 kGy, respectively. Irradiated samples with OP extract and BF had substantially lower total aerobic bacterial counts than the control had. Samples with added OP extract and BF had lower peroxide values than the control had. Sensory evaluation indicated that overall acceptability of treated samples was not changed up to 2 kGy. Therefore, EB irradiation, combined with OP extract and BF, has improved the microbiological safety with no negative effects on the quality of pork jerky.

  18. Effect of two virus inactivation methods: electron beam irradiation and binary ethylenimine treatment on determination of reproductive hormones in equine plasma.

    PubMed

    Kyvsgaard, N C; Høier, R; Brück, I; Nansen, P

    1997-01-01

    Ionizing irradiation and binary ethylenimine treatment have previously been shown to be effective for in-vitro inactivation of virus in biological material. In the present study the 2 methods were tested for possible effects on measurable concentrations of reproductive hormones in equine plasma (luteinizing hormone (LH), folliclestimulating hormone (FSH), progesterone (P4), and oestradiol-17 beta (E2)). The inactivation methods were electron beam irradiation with a dose from 11 to 44 kGy or treatment with binary ethylenimine (BEI) in concentrations of 1 and 5 mmol/L. Generally, there was a close correlation (r > 0.8, < 0.001) between pre- and post-treatment hormone levels. Thus, the different phases of the oestrous cycle could be distinguished on the basis of measured hormone concentrations of treated samples. However, both treatments significantly changed hormone concentrations of the plasma samples. For LH, FSH, and E2 the effect of irradiation and BEI treatment was depressive and dose-dependent. For P4 the effect of irradiation was also depressive and dose-dependent. However, the highest dose of BEI resulted in an increase of measured P4 concentration, which may be attributed to changes in the plasma matrix due to the treatment. Although the treatments affected measured hormone concentrations, the close correlation between pre-treatment and post-treatment measurements means that the diagnostic value will remain unchanged.

  19. Effects of temperature, packaging and electron beam irradiation processing conditions on the property behaviour of Poly (ether-block-amide) blends.

    PubMed

    Murray, Kieran A; Kennedy, James E; McEvoy, Brian; Vrain, Olivier; Ryan, Damien; Cowman, Richard; Higginbotham, Clement L

    2014-06-01

    The radiation stability of Poly (ether-block-amide) (PEBA) blended with a multifunctional phenolic antioxidant and a hindered amide light stabiliser was examined under various temperatures, packaging and electron beam processing conditions. FTIR revealed that there were slight alterations to the PEBA before irradiation; however, these became more pronounced following irradiation. The effect of varying the temperature, packaging and processing conditions on the resultant PEBA properties was apparent. For example, rheology demonstrated that the structural properties could be enhanced by manipulating the aforementioned criteria. Mechanical testing exhibited less radiation resistance when the PEBA samples were vacuum packed and exposed to irradiation. MFI and AFM confirmed that the melting strength and surface topography could be reduced/increased depending on the conditions employed. From this study it was concluded that virgin PEBA submerged in dry ice with non-vacuum packaging during the irradiation process, provided excellent radiation resistance (20.9% improvement) in contrast to the traditional method. Copyright © 2014. Published by Elsevier B.V.

  20. Susceptibility of Murine Norovirus and Hepatitis A Virus to Electron Beam Irradiation in Oysters and Quantifying the Reduction in Potential Infection Risks

    PubMed Central

    Praveen, Chandni; Dancho, Brooke A.; Kingsley, David H.; Calci, Kevin R.; Meade, Gloria K.; Mena, Kristina D.

    2013-01-01

    Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D10 value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 105 PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 102 PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced. PMID:23584781

  1. Susceptibility of murine norovirus and hepatitis A virus to electron beam irradiation in oysters and quantifying the reduction in potential infection risks.

    PubMed

    Praveen, Chandni; Dancho, Brooke A; Kingsley, David H; Calci, Kevin R; Meade, Gloria K; Mena, Kristina D; Pillai, Suresh D

    2013-06-01

    Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D(10) value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 10(5) PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 10(2) PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced.

  2. Measurement of radio wave reflection due to temperature rising from rock salt and ice irradiated by an electron beam for an ultra-high-energy neutrino detector

    SciTech Connect

    Tanikawa, Takahiro; Chiba, Masami; Kamijo, Toshio; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kon, Tadashi; Shimizu, Yutaka; Utsumi, Michiaki; Fujii, Masatoshi

    2012-11-12

    An ultra-high-energy neutrino (UHE{nu}) gives temperature rise along the hadronic and electromagnetic shower when it enters into rock salt or ice. Permittivities of them arise with respect the temperatures at ionization processes of the UHE{nu} shower. It is expected by Fresnel's formula that radio wave reflects at the irregularity of the permittivity in the medium. We had found the radio wave reflection effect in rock salt. The reflection effect and long attenuation length of radio wave in rock salt and ice would yield a new UHE{nu} detection method. An experiment for ice was performed to study the reflection effect. A coaxial tube was filled with rock salt powder or ice. Open end of the coaxial tube was irradiated by a 2 MeV electron beam. Radio wave of 435 MHz was introduced to the coaxial tube. We measured the reflection wave from the open end. We found the radio wave reflection effect due to electron beam irradiation in ice as well as in rock salt.

  3. Measurement of radio wave reflection due to temperature rising from rock salt and ice irradiated by an electron beam for an ultra-high-energy neutrino detector

    NASA Astrophysics Data System (ADS)

    Tanikawa, Takahiro; Chiba, Masami; Kamijo, Toshio; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kon, Tadashi; Shimizu, Yutaka; Utsumi, Michiaki; Fujii, Masatoshi

    2012-11-01

    An ultra-high-energy neutrino (UHEν) gives temperature rise along the hadronic and electromagnetic shower when it enters into rock salt or ice. Permittivities of them arise with respect the temperatures at ionization processes of the UHEν shower. It is expected by Fresnel's formula that radio wave reflects at the irregularity of the permittivity in the medium. We had found the radio wave reflection effect in rock salt. The reflection effect and long attenuation length of radio wave in rock salt and ice would yield a new UHEν detection method. An experiment for ice was performed to study the reflection effect. A coaxial tube was filled with rock salt powder or ice. Open end of the coaxial tube was irradiated by a 2 MeV electron beam. Radio wave of 435 MHz was introduced to the coaxial tube. We measured the reflection wave from the open end. We found the radio wave reflection effect due to electron beam irradiation in ice as well as in rock salt.

  4. The Efficacy of Electron Beam Irradiated Bacterial Cellulose Membranes as Compared with Collagen Membranes on Guided Bone Regeneration in Peri-Implant Bone Defects

    PubMed Central

    Lee, So-Hyoun; An, Sung-Jun; Lim, Youn-Mook; Huh, Jung-Bo

    2017-01-01

    Bacterial cellulose (BC) is a natural polysaccharide produced by some bacteria, and consists of a linear polymer linked by β-(1,4) glycosidic bonds. BC has been developed as a material for tissue regeneration purposes. This study was conducted to evaluate the efficacy of resorbable electron beam irradiated BC membranes (EI-BCMs) for guided bone regeneration (GBR). The electron beam irradiation (EI) was introduced to control the biodegradability of BC for dental applications. EI-BCMs had higher porosity than collagen membranes (CMs), and had similar wet tensile strengths to CMs. NIH3T3 cell adhesion and proliferation on EI-BCMs were not significantly different from those on CMs (p > 0.05). Micro-computed tomography (μCT) and histometric analysis in peri-implant dehiscence defects of beagle dogs showed that EI-BCMs were non-significantly different from CMs in terms of new bone area (NBA; %), remaining bone substitute volume (RBA; %) and bone-to-implant contact (BIC; %) (p > 0.05). These results suggest resorbable EI-BCMs can be used as an alternative biomaterial for bone tissue regeneration. PMID:28862689

  5. Characteristics of microdomains and microdomain patterns recorded by electron beam irradiation on Y-cut LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Kokhanchik, L. S.; Gainutdinov, R. V.; Lavrov, S. D.; Volk, T. R.

    2015-08-01

    We present the results of investigations of planar domain patterns (isolated domains and domain gratings) fabricated by irradiation of the nonpolar Y-surface of LiNbO3 crystals by an electron beam (EB) incident normally onto the surface. The EB recorded domains were investigated using atomic force microscopy, confocal second harmonic generation microscopy, and chemical etching as an auxiliary method. The dependence of the domain characteristics on irradiation conditions (acceleration voltage U, EB current I, and irradiation time tirr) were determined. The length Ld of both isolated domains and domain gratings along the polar axis Z grows linearly with tirr (at U, I = const) with no tending to saturation. The plots Ld(tirr) obtained for U = 10 and 15 kV are practically identical, whereas the values of Ld for U = 5 kV are essentially lower. The domain thickness Td along the Y-direction, i.e., the depth of the switched layer grows with acceleration voltage U. These results are discussed in terms of space-charge fields formation arising under EB irradiation of insulators. The linearity of Ld(tirr) is accounted for by the frontal domain growth via the viscous friction law. The experimental dependence of Td on U supports the suggestion that the domain thickness is determined by the penetration depth Re of primary electrons, which in turn is governed by U. The difference in Ld(tirr) plots for different U is accounted for by different electron emission σ. Indirect evidences of a defect structure modification in a thin surface layer with respect to the crystal bulk are obtained.

  6. Characteristics of microdomains and microdomain patterns recorded by electron beam irradiation on Y-cut LiNbO{sub 3} crystals

    SciTech Connect

    Kokhanchik, L. S.; Gainutdinov, R. V.; Volk, T. R.; Lavrov, S. D.

    2015-08-21

    We present the results of investigations of planar domain patterns (isolated domains and domain gratings) fabricated by irradiation of the nonpolar Y-surface of LiNbO{sub 3} crystals by an electron beam (EB) incident normally onto the surface. The EB recorded domains were investigated using atomic force microscopy, confocal second harmonic generation microscopy, and chemical etching as an auxiliary method. The dependence of the domain characteristics on irradiation conditions (acceleration voltage U, EB current I, and irradiation time t{sub irr}) were determined. The length L{sub d} of both isolated domains and domain gratings along the polar axis Z grows linearly with t{sub irr} (at U, I = const) with no tending to saturation. The plots L{sub d}(t{sub irr}) obtained for U = 10 and 15 kV are practically identical, whereas the values of L{sub d} for U = 5 kV are essentially lower. The domain thickness T{sub d} along the Y-direction, i.e., the depth of the switched layer grows with acceleration voltage U. These results are discussed in terms of space-charge fields formation arising under EB irradiation of insulators. The linearity of L{sub d}(t{sub irr}) is accounted for by the frontal domain growth via the viscous friction law. The experimental dependence of T{sub d} on U supports the suggestion that the domain thickness is determined by the penetration depth R{sub e} of primary electrons, which in turn is governed by U. The difference in L{sub d}(t{sub irr}) plots for different U is accounted for by different electron emission σ. Indirect evidences of a defect structure modification in a thin surface layer with respect to the crystal bulk are obtained.

  7. Electron beam polarimetry

    SciTech Connect

    Sinclair, C.K.

    1998-12-01

    Along with its well known charge and mass, the electron also carries an intrinsic angular momentum, or {ital spin}. The rules of quantum mechanics allow us to measure only the probability that the electron spin is in one of two allowed spin states. When a beam carries a net excess of electrons in one of these two allowed spin states, the beam is said to be {ital polarized}. The beam polarization may be measured by observing a sufficient number of electrons scattered by a spin-dependent interaction. For electrons, the useful scattering processes involve Coulomb scattering by heavy nuclei, or scattering from either polarized photons or other polarized electrons (known as Mott, Compton, and Mo/ller scattering, respectively). In this tutorial, we will briefly review how beam polarization is measured through a general scattering process, followed by a discussion of how the three scattering processes above are used to measure electron beam polarization. Descriptions of electron polarimeters based on the three scattering processes will be given. {copyright} {ital 1998 American Institute of Physics.}

  8. Electron beam polarimetry

    NASA Astrophysics Data System (ADS)

    Sinclair, Charles K.

    1998-12-01

    Along with its well known charge and mass, the electron also carries an intrinsic angular momentum, or spin. The rules of quantum mechanics allow us to measure only the probability that the electron spin is in one of two allowed spin states. When a beam carries a net excess of electrons in one of these two allowed spin states, the beam is said to be polarized. The beam polarization may be measured by observing a sufficient number of electrons scattered by a spin-dependent interaction. For electrons, the useful scattering processes involve Coulomb scattering by heavy nuclei, or scattering from either polarized photons or other polarized electrons (known as Mott, Compton, and Mo/ller scattering, respectively). In this tutorial, we will briefly review how beam polarization is measured through a general scattering process, followed by a discussion of how the three scattering processes above are used to measure electron beam polarization. Descriptions of electron polarimeters based on the three scattering processes will be given.

  9. Bragg amplification of the Si {kappa}{alpha} line emitted from a Mo/Si multilayer irradiated by an electron beam

    SciTech Connect

    Jonnard, P.; Bonnelle, C.; Pardo, B.; Andre, J.-M.; Bridou, F

    2003-01-24

    We report on the intensity modulation of the Si {kappa}{alpha} line emitted from a Mo/Si multilayer as a function of the exit angle of the photons. The observation takes place around the direction corresponding to the Bragg diffraction of Si {kappa}{alpha} by the multilayer. The sample is irradiated by an electron beam whose the energy is varied between 2 and 6 keV. An important intensity variation is observed within the angular range corresponding to the diffraction pattern of the emitting structure. A 15 % enhancement of the emitted radiation is measured in the Bragg direction of the multilayer, whatever the incident electron energy. This amplification is interpreted on the basis of the reciprocity theorem. A possible application as x-ray resonator is suggested.

  10. Effect of electron beam irradiation on the structural properties of poly(vinyl alcohol) formulations with triphenyl tetrazolium chloride dye (TTC)

    NASA Astrophysics Data System (ADS)

    Ali, Z. I.; Said, Hossam M.; Ali, H. E.

    2006-01-01

    Films of poly(vinyl alcohol) (PVA) composites with triphenyl tetrazolium chloride (TTC) dye were prepared and exposed to various radiation doses delivered by accelerated electrons. The results showed that at a low dose of 50 kGy, the colour difference (Δ E*) of PVA/TTC films was increased by ˜10 times of the initial value. However, the change in colour differences did not go systematically with increasing the TTC content, in which the composite with 1.5 wt% displayed higher value than that with 3.5 wt%. The differential scanning calorimetry (DSC) showed that the presence of the TTC dye caused a depression in the melting point ( Tm) and heat of fusion (Δ Hf) of the PVA bulk polymer. However, the thermogravimetric analysis (TGA) showed that the presence of the TTC dye improved the thermal stability of PVA. Also, the tensile strength at break of PVA/TTC composites was improved after electron beam irradiation.

  11. SU-E-T-447: Growth of Metal Whiskers Under External Beam Irradiation: Experimental Evidence and Implications in Medical Electronic Devices for Radiation Therapy Treatments

    SciTech Connect

    Shvydka, D; Warrell, G; Parsai, E; Karpov, V; Vasko, A

    2015-06-15

    Purpose: Thin metallic protrusions, termed “whiskers,” have been identified as a cause of failure in devices ranging from satellites to pacemakers. For decades, lead was used in tin-based soldering alloys to suppress whisker formation. With the adoption of the Restriction of Hazardous Substances act and the expiration of its exemption on medical devices, including implanted medical devices (IMDs), electronic circuits are required to be lead-free as of July 2014. The effect of radiation on such soldering components remains unknown. Methods: We have irradiated a thin (150 nm) tin metal layer, deposited on a 3 mm thick glass substrate, with a 6 MeV medical linac (Varian TrueBeam) electron beam in five 2-hour long sessions. After receiving ∼10 kGy, whisker growth on the sample was assessed with scanning electron microscopy and compared to a reference sample not exposed to radiation. Results: After 10 hours of irradiation, the sample was found to develop intense whisker infestation, while the reference sample remained in its pristine as-deposited condition. Repeating the same irradiation schedule generated more and longer whiskers. The observed phenomenon can be explained through charge accumulation in the glass substrate, generating an electric field that promotes whisker growth. The observed substrate glass darkening under irradiation points towards development of color centers related to charge trapping. Experiments on the same type of samples with direct application of the external field in a capacitor-like setting also resulted in intense whisker growth. Conclusion: Extreme care should be taken in dealing with all electronic devices, especially IMDs, produced with lead-free solder and components, subject to radiation exposure. While in our experiments strong electric fields were intentionally generated to accelerate whisker growth over hours, in everyday use the circuit soldering may cause problems in a matter of days or months. Designated reliability testing

  12. Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

    SciTech Connect

    Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael; Abril, Isabel; Kostarelos, Kostas

    2011-09-01

    The effect of bulk and surface excitations to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes (MWNTs) is studied using the dielectric formalism. Calculations are based on a semiempirical dielectric response function for MWCNTs determined by means of a many-pole plasmon model with parameters adjusted to available experimental spectroscopic data under theoretical sum-rule constrains. Finite-size effects are considered in the context of electron gas theory via a boundary correction term in the plasmon dispersion relations, thus, allowing a more realistic extrapolation of the electronic excitation spectrum over the whole energy-momentum plane. Energy-loss differential and total inelastic scattering cross sections as a function of electron energy and distance from the surface, valid over the energy range {approx}50-30,000 eV, are calculated with the individual contribution of bulk and surface excitations separated and analyzed for the case of normally incident and escaping electrons. The sensitivity of the results to the various approximations for the spatial dispersion of the electronic excitations is quantified. Surface excitations are shown to have a strong influence upon the shape and intensity of the energy-loss differential cross section in the near surface region whereas the general notion of a spatially invariant inelastic mean free path inside the material is found to be of good approximation.

  13. Micro-nanopores fabricated by high-energy electron beam irradiation: suitable structure for controlling pesticide loss.

    PubMed

    Xiang, Yubin; Wang, Ning; Song, Jimei; Cai, Dongqing; Wu, Zhengyan

    2013-06-05

    Pesticide sprayed onto crop leaves tends to be washed off by rainwater and discharge into the environment through leaching and runoff, resulting in severe pollution to both soil and water. Here, to control pesticide loss, we developed a loss-control pesticide (LCP) by adding modified natural nanoclay (diatomite) through high-energy electron beam (HEEB) to traditional pesticide. After HEEB treatment, the originally clogged pores in diatomite opened, resulting in plenty of micro-nanopores in diatomite, which are beneficial for the pesticide molecules to access and be adsorbed. This pesticide-diatomite complex tended to be retained by the rough surface of crop leaves, displaying a high adhesion performance onto the leaves, so that the pesticide loss reduced, sufficient pesticide for crops was supplied, and the pollution risk of the pesticide could be substantially lowered.

  14. Thermal Cycling Behavior of Thermal Barrier Coatings with MCrAlY Bond Coat Irradiated by High-Current Pulsed Electron Beam.

    PubMed

    Cai, Jie; Lv, Peng; Guan, Qingfeng; Xu, Xiaojing; Lu, Jinzhong; Wang, Zhiping; Han, Zhiyong

    2016-11-30

    Microstructural modifications of a thermally sprayed MCrAlY bond coat subjected to high-current pulsed electron beam (HCPEB) and their relationships with thermal cycling behavior of thermal barrier coatings (TBCs) were investigated. Microstructural observations revealed that the rough surface of air plasma spraying (APS) samples was significantly remelted and replaced by many interconnected bulged nodules after HCPEB irradiation. Meanwhile, the parallel columnar grains with growth direction perpendicular to the coating surface were observed inside these bulged nodules. Substantial Y-rich Al2O3 bubbles and varieties of nanocrystallines were distributed evenly on the top of the modified layer. A physical model was proposed to describe the evaporation-condensation mechanism taking place at the irradiated surface for generating such surface morphologies. The results of thermal cycling test showed that HCPEB-TBCs presented higher thermal cycling resistance, the spalling area of which after 200 cycles accounted for only 1% of its total area, while it was about 34% for APS-TBCs. The resulting failure mode, i.e., in particular, a mixed delamination crack path, was shown and discussed. The irradiated effects including compact remelted surface, abundant nanoparticles, refined columnar grains, Y-rich alumina bubbles, and deformation structures contributed to the formation of a stable, continuous, slow-growing, and uniform thermally grown oxide with strong adherent ability. It appeared to be responsible for releasing stress and changing the cracking paths, and ultimately greatly improving the thermal cycling behavior of HCPEB-TBCs.

  15. Pulsed electron beam precharger

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    Electrostatic collection of a high resistivity aerosol using the Electron Beam Precipitator (EBP) collecting section was demonstrated during this reporting period (Quarter Five). Collection efficiency experiments were designed to confirm and extend some of the work performed under the previous contract. The reason for doing this was to attempt to improve upon the collection efficiency of the precipitator alone when testing with a very high resistivity, moderate-to-high concentration dust load. From the collector shakedown runs, a set of suitable operational parameters were determined for the downstream electrostatic collecting sections of the Electron Beam Precipitator wind tunnel. These parameters, along with those for the MINACC electron beam, will generally be held constant while the numerous precharging parameters are varied to produce an optimum particle charge. The electrostatic collector experiments were part of a larger, comprehensive investigation on electron beam precharging of high resistivity aerosol particles performed during the period covered by Quarters Five, Six, and Seven. This body of work used the same experimental apparatus and procedures and the experimental run period lasted nearly continuously for six months. A summary of the Quarter Five work is presented in the following paragraphs. Section II-A of TPR 5 contains a report on the continuing effort which was expended on the modification and upgrade of the pulsed power supply and the monitoring systems prior to the initiation of the electron beam precharging experimental work.

  16. Pulsed electron beam precharger

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1991-01-01

    Electron beam precharging of a high resistivity aerosol was successfully demonstrated during this reporting period (Quarters Five and Six). The initial E-beam particle precharging experiments completed this term were designed to confirm and extend some of the work performed under the previous contract. There are several reasons for doing this: (1) to re-establish a baseline performance criterion for comparison to other runs, (2) to test several recently upgraded or repaired subsystems, and (3) to improve upon the collection efficiency of the electron beam precipitator when testing precharging effectiveness with a very high resistivity, moderate-to-high concentration dust load. In addition, these shakedown runs were used to determine a set of suitable operational parameters for the wind tunnel, the electrostatic collecting sections, and the MINACC E-beam accelerator. These parameters will generally be held constant while the precharging parameters are varied to produce an optimum particle charge.

  17. Surface charge and carbon contamination on an electron-beam-irradiated hydroxyapatite thin film investigated by photoluminescence and phase imaging in atomic force microscopy.

    PubMed

    Hristu, Radu; Tranca, Denis E; Stanciu, Stefan G; Gregor, Maros; Plecenik, Tomas; Truchly, Martin; Roch, Tomas; Tofail, Syed A M; Stanciu, George A

    2014-04-01

    The surface properties of hydroxyapatite, including electric charge, can influence the biological response, tissue compatibility, and adhesion of biological cells and biomolecules. Results reported here help in understanding this influence by creating charged domains on hydroxyapatite thin films deposited on silicon using electron beam irradiation and investigating their shape, properties, and carbon contamination for different doses of incident injected charge by two methods. Photoluminescence laser scanning microscopy was used to image electrostatic charge trapped at pre-existing and irradiation-induced defects within these domains, while phase imaging in atomic force microscopy was used to image the carbon contamination. Scanning Auger electron spectroscopy and Kelvin probe force microscopy were used as a reference for the atomic force microscopy phase contrast and photoluminescence laser scanning microscopy measurements. Our experiment shows that by combining the two imaging techniques the effects of trapped charge and carbon contamination can be separated. Such separation yields new possibilities for advancing the current understanding of how surface charge influences mediation of cellular and protein interactions in biomaterials.

  18. Temperature distribution in a sample with second-phase microinclusions during irradiation by a low-energy high-current pulsed electron beam

    NASA Astrophysics Data System (ADS)

    Shepel', D. A.; Markov, A. B.

    2017-02-01

    Using the methods of numerical integration, a temperature field has been calculated that arose in the surface layer of titanium nickelide target with NiTi2 intermetallic inclusions during irradiation by a lowenergy high-current electron beam with a duration of the order of a microsecond. The calculated temperature field has been compared with that obtained previously for a target of stainless steel 316L containing MnS inclusions. It has been found that, as in the case of stainless steel, the regions of inclusions are overheated. However, the temperature increase for NiTi2 (12 K) is significantly lower than in the case of stainless steel 316L (283 K). The dynamics of melting of these systems are also considerably different.

  19. Electron beam dose calculations.

    PubMed

    Hogstrom, K R; Mills, M D; Almond, P R

    1981-05-01

    Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams. The off-axis dependence of the pencil beam dose distribution is described by the Fermi-Eyges theory of thick-target multiple Coulomb scattering. Measured square-field depth-dose data serve as input for the calculations. Air gap corrections are incorporated and use data from'in-air' measurements in the penumbra of the beam. The effective depth, used to evaluate depth-dose, and the sigma of the off-axis Gaussian spread against depth are calculated by recursion relations from a CT data matrix for the material underlying individual pencil beams. The correlation of CT number with relative linear stopping power and relative linear scattering power for various tissues is shown. The results of calculations are verified by comparison with measurements in a 17 MeV electron beam from the Therac 20 linear accelerator. Calculated isodose lines agree nominally to within 2 mm of measurements in a water phantom. Similar agreement is observed in cork slabs simulating lung. Calculations beneath a bone substitute illustrate a weakness in the calculation. Finally a case of carcinoma in the maxillary antrum is studied. The theory suggests an alternative method for the calculation of depth-dose of rectangular fields.

  20. Effects of low-energy electron beam irradiation on flexural properties of self-curing acrylic resin.

    PubMed

    Ito, Kyosuke; Nomura, Akiko; Nomura, Shuichi; Watanabe, Kouichi

    2014-01-01

    The purpose of this study was to confirm the effectiveness of LEB irradiation onto the polymer powder for improving the mechanical properties of self-curing acrylic resin. The polymer powder of self-curing acrylic resin was irradiated with total LEB doses of 25, 50, 75 or 100kGy. Non-irradiated powder was used as a control. After LEB irradiation, ESR measurement, weight-average molecular weight measurement and three-point bending test were performed. ESR spectrum of control had no peaks. After LEB irradiation, nine peaks were observed in each ESR spectrum, which indicates the presence of free radicals from main polymer chain. The quantity of free radicals increased linearly up to 100kGy. Calibrated weight-average molecular weights were as follows: control, 960,000; 25kGy, 500,000; 50kGy, 440,000; 75kGy, 410,000; and 100kGy, 390,000. Molecular weight decreased with increasing LEB irradiation dose. The mean values of flexural strength (MPa) were as follows: control, 61.5±3.0; 25kGy, 68.1±4.0; 50kGy, 73.0±1.9; 75kGy, 70.4±3.6; and 100kGy, 67.7±2.3. The flexural strength of the specimens cured with the LEB-irradiated powder was significantly higher than that of control (p<0.01). These results indicate that flexural strength of polymer materials cured with the LEB-irradiated powder increases because of increase in cross-linking structure. It is confirmed that LEB irradiation onto the polymer powder of self-curing acrylic resin improves the flexural strength. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  1. Synergistic effect of combination of Irganox 1010 and zinc stearate on thermal stabilization of electron beam irradiated HDPE/EVA both in hot water and oven

    NASA Astrophysics Data System (ADS)

    Hassanpour, S.; Khoylou, F.

    2007-11-01

    Thermo-oxidative stability of HDPE/EVA blends can be considerably increased by combination of a high-molecular weight phenolic antioxidant and zinc stearate. In this work, the post-irradiation thermal stability of HDPE/EVA blends has been studied. High-density polyethylene and its blends with ethylene-vinylacetate copolymer in both pure form and mixed with Irganox 1010 and zinc stearate were exposed to electron beam radiation at doses between 80 and 150 kGy, at room temperature, in air. In order to evaluate the thermal stability of the samples, post-irradiation heat treatments were done in both hot water bath at 95 °C and in an oven at 140 °C. The mechanical properties and changes in the chemical structure were determined during thermal aging in hot water and oven. The gel content was enhanced by increasing EVA concentration in all applied doses. The stabilized blends have lower gel content than the unstabilized samples. From the results of heat aging treatments it was observed that the thermal stability of the unstabilized blend samples was lower than HDPE. Thermal stability of the samples has been improved by incorporation of Irganox 1010 and zinc stearate. Formation of hydroxyl group was insignificant for stabilized samples during heat aging in both conditions. Also, the changes in the value of oxidation induction time (OIT) for the stabilized samples were negligible after prolonged immersion in hot water.

  2. Very high dose electron irradiation effects on photoluminescence from GaInNAs/GaAs quantum wells grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Pavelescu, E.-M.; Bălţăţeanu, N.; Spânulescu, S. I.; Arola, E.

    2017-02-01

    The effects of 7 MeV electron irradiation at very high doses of 2 ×1017 and 1.5 ×1018electrons /cm2 and subsequent rapid thermal annealing on photoluminescence from a strain-compensated GaInAsN/GaAsN/GaAs quantum well structure are investigated. A large additional blueshift of photoluminescence has been observed from the lower-dose irradiated sample as compared to the non-irradiated one when annealed after the irradiation. This additional blueshift will become considerably reduced by an ageing effect, which occurs already at room temperature. The mechanism causing the additional blueshift of photoluminescence and its reduction is qualitatively assigned to metastable complex defects promoted by electron irradiation in the nitrogen containing layers. No such additional blueshift of photoluminescence under the thermal treatment has been observed in the higher-dose irradiated sample.

  3. Electron Beam Applications in Chemical Processing

    NASA Astrophysics Data System (ADS)

    Martin, D.; Dragusin, M.; Radoiu, M.; Moraru, R.; Oproiu, C.; Cojocaru, G.; Margarit, C.

    1997-05-01

    Our recent results in the field of polymeric materials obtained by electron beam irradiation are presented. Two types of polymeric flocculants and three hydrogels are described. The effects of radiation absorbed dose and chemical composition of the irradiated solutions upon the polymeric materials characteristics are discussed. The required absorbed dose levels to produce the polymeric flocculants are in the range of 0.4 kGy to 1 kGy, and 4 kGy to 12 kGy for hydrogels. Experimental results obtained by testing polymeric flocculants with waste water from food industry are given. Plymeric materials processing was developed on a pilot small scale level with a 0.7 kW and 5.5 MeV linac built in Romania. A new facility for application of combined electron beam and microwave irradiation in the field of polymeric materials preparation is presently under investigation. Preliminary results have demonstrated that some polymeric flocculants characteristics, such as linearity, were improved by using combined electron beam and microwave irradiation. Also, the absorbed dose levels decreases in comparison with those required when only electron beam irradiation was used.

  4. Hardness distribution and tensile properties in an electron beam weldment of F82H irradiated in HFIR

    NASA Astrophysics Data System (ADS)

    Oka, H.; Hashimoto, N.; Muroga, T.; Kimura, A.; Sokolov, M. A.; Yamamoto, T.; Ohnuki, S.

    2014-12-01

    F82H-IEA and its EB-weld joint were irradiated at 573 and 773 K up to 9.6 dpa and the irradiation effect on its mechanical properties and microstructure were investigated. A hardness profile across the weld joint before irradiation showed the hardness in transformed region (TR) was high and especially that in the edge of TR was the highest (high hardness region: HHR) compared to base metal (BM). These hardness distribution was correspond to grain size distribution. After irradiation, hardening in HHR was small compared to other region in the sample. In tensile test, the amount of hardening in yield strength and ultimate tensile strength of F82H EB-weld joint was almost similar to that of F82H-IEA but the fracture position of EB-weld joint was at the boundary of TR and BM. Therefore, the TR/BM boundary is the structural weak point in F82H EB-weld joint after irradiation. As the plastic instability was observed, the dislocation channeling deformation can be expected though the dislocation channel was not observed in this study.

  5. Cylindrical electron beam diode

    DOEpatents

    Bolduc, Paul E.

    1976-01-01

    A diode discharge device may include a tubular anode concentrically encircled by and spaced from a tubular cathode electrode with ends intermediate the ends of said anode electrode, and a metal conductive housing having a tubular wall disposed around the cathode electrode with end walls connected to the anode electrode. High energy electron current coupling is through an opening in the housing tubular wall to a portion of the cathode electrode intermediate its ends. Suitable utilization means may be within the anode electrode at positions to be irradiated by electrons emitted from the cathode electrode and transmitted through the anode walls.

  6. Beam Stop for Electron Accelerator Beam Characterisation

    NASA Astrophysics Data System (ADS)

    Roach, Greg; Sharp, Vic; Tickner, James; Uher, Josef

    2009-08-01

    Electron linear accelerator applications involving the generation of hard X-rays frequently require accurate knowledge of the electron beam parameters. We developed a beam stop device which houses a tungsten Bremsstrahlung target and enables the electron beam current, energy and position to be monitored. The beam stop consisted of four plates. The first was a removable aluminium (Al) transmission plate. Then followed the tungsten target. Behind the target there were four Al quadrant plates for beam position measurement. The last plate was a thick Al back-stop block. Currents from the four quadrants and the back-stop were measured and the beam lateral position, energy and current were calculated. The beam stop device was optimised using Monte-Carlo simulation, manufactured (including custom-made electronics and software) in our laboratory and tested at the ARPANSA (Australian Radiation Protection and Nuclear Safety Agency) linear accelerator in Melbourne. The electron beam energy was determined with a precision of 60 keV at beam energies between 11 and 21 MeV and the lateral beam position was controlled with a precision of 200 mum. The relative changes of the beam current were monitored as well.

  7. Electron beam generation in Tevatron electron lenses

    SciTech Connect

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.; /Novosibirsk, IYF

    2006-08-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices.

  8. Electron beam damage in oxides: a review.

    PubMed

    Jiang, Nan

    2016-01-01

    This review summarizes a variety of beam damage phenomena relating to oxides in (scanning) transmission electron microscopes, and underlines the shortcomings of currently popular mechanisms. These phenomena include mass loss, valence state reduction, phase decomposition, precipitation, gas bubble formation, phase transformation, amorphization and crystallization. Moreover, beam damage is also dependent on specimen thickness, specimen orientation, beam voltage, beam current density and beam size. This article incorporates all of these damage phenomena and experimental dependences into a general description, interpreted by a unified mechanism of damage by induced electric field. The induced electric field is produced by positive charges, which are generated from excitation and ionization. The distribution of the induced electric fields inside a specimen is beam-illumination- and specimen-shape- dependent, and associated with the experimental dependence of beam damage. Broadly speaking, the mechanism operates differently in two types of material. In type I, damage increases the resistivity of the irradiated materials, and is thus divergent, resulting in phase separation. In type II, damage reduces the resistivity of the irradiated materials, and is thus convergent, resulting in phase transformation. Damage by this mechanism is dependent on electron-beam current density. The two experimental thresholds are current density and irradiation time. The mechanism comes into effect when these thresholds are exceeded, below which the conventional mechanisms of knock-on and radiolysis still dominate.

  9. Electron beam stimulated spin reorientation

    NASA Astrophysics Data System (ADS)

    Monchesky, T. L.; Unguris, J.; Celotta, R. J.

    2003-05-01

    Using scanning electron microscopy with polarization analysis, we observed the electron beam induced switching of the magnetic state of epitaxial single-crystal Fe(110) films grown on atomically flat cleaved GaAs(110). For low film thickness the magnetization lies along the [-110] in-plane direction, while above a thickness of 19 monolayers, the ground state magnetization configuration switches to the [001] in-plane direction. If Fe films are grown to a thickness greater than the critical thickness of the reorientation, the magnetization is caught in a metastable state, oriented along [-110]. We discovered that we can locally switch the metastable state to the stable [001] direction by irradiating the metastable magnetic state with a suitable electron current density. The reversal proceeds by the nucleation and growth of lancet-shaped domains that move in discrete jumps between pinning sites. Our results show that there is a permanent reduction of the strength of defect sites without a permanent change in the overall anisotropy. We demonstrate how an electron beam can be used to locally control domain structure.

  10. Measuring electron beam polarization

    NASA Astrophysics Data System (ADS)

    Napolitano, J.

    1992-12-01

    A two-hour discussion session was held on electron beam polarimetry including representatives from Halls A, B, and C. Presentations included a description of an existing Mo/ller polarimeter at the MIT-Bates laboratory, plans for Mo/ller polarimeters in Halls A and B, and a Compton (i.e., ``laser backscatter'') polarimeter planned for Hall A. This paper is a summary of those discussions.

  11. Electron beam extraction on plasma cathode electron sources system

    NASA Astrophysics Data System (ADS)

    Purwadi, Agus; Taufik, M., Lely Susita R.; Suprapto, Saefurrochman, H., Anjar A.; Wibowo, Kurnia; Aziz, Ihwanul; Siswanto, Bambang

    2017-03-01

    ELECTRON BEAM EXTRACTION ON PLASMA CATHODE ELECTRON SOURCES SYSTEM. The electron beam extraction through window of Plasma Generator Chamber (PGC) for Pulsed Electron Irradiator (PEI) device and simulation of plasma potential has been studied. Plasma electron beam is extracted to acceleration region for enlarging their power by the external accelerating high voltage (Vext) and then it is passed foil window of the PEI for being irradiated to any target (atmospheric pressure). Electron beam extraction from plasma surface must be able to overcome potential barrier at the extraction window region which is shown by estimate simulation (Opera program) based on data of plasma surface potential of 150 V with Ueks values are varied by 150 kV, 175 kV and 200 kV respectively. PGC is made of 304 stainless steel with cylindrical shape in 30 cm of diameter, 90 cm length, electrons extraction window as many as 975 holes on the area of (15 × 65) cm2 with extraction hole cell in 0.3 mm of radius each other, an cylindrical shape IEP chamber is made of 304 stainless steel in 70 cm diameter and 30 cm length. The research result shown that the acquisition of electron beam extraction current depends on plasma parameters (electron density ne, temperature Te), accelerating high voltage Vext, the value of discharge parameter G, anode area Sa, electron extraction window area Se and extraction efficiency value α.

  12. Electron Beam Scanning in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Jongen, Yves; Herer, Arnold

    1996-05-01

    Scanned electron beams are used within many industries for applications such as sterilization of medical disposables, crosslinking of wire and cables insulating jackets, polymerization and degradation of resins and biomaterials, modification of semiconductors, coloration of gemstones and glasses, removal of oxides from coal plant flue gasses, and the curing of advanced composites and other molded forms. X-rays generated from scanned electron beams make yet other applications, such as food irradiation, viable. Typical accelerators for these applications range in beam energy from 0.5MeV to 10 MeV, with beam powers between 5 to 500kW and scanning widths between 20 and 300 cm. Since precise control of dose delivery is required in many of these applications, the integration of beam characteristics, product conveyance, and beam scanning mechanisms must be well understood and optimized. Fundamental issues and some case examples are presented.

  13. Instability of nanoscale metallic particles under electron irradiation in TEM

    NASA Astrophysics Data System (ADS)

    Chen, X. Y.; Zhang, S. G.; Xia, M. X.; Li, J. G.

    2016-03-01

    The stability of nano metallic glass under electron beam in transmission electron microscope (TEM) was investigated. The most common voltage of TEM used in metallic materials characterization was either 200 kV or 300 kV. Both situations were investigated in this work. An amorphous metallic particle with a dimension of a few hundred nanometers was tested under 300 keV electron irradiation. New phase decomposed from the parent phase was observed. Moreover, a crystal particle with the same composition and dimension was tested under 200 keV irradiation. Decomposition process also occurred in this situation. Besides, crystal orientation modification was observed during irradiation. These results proved that the electron beam in TEM have an effect on the stability of nanoscale samples during long time irradiation. Atomic displacement was induced and diffusion was enhanced by electron irradiation. Thus, artifacts would be induced when a nanoscale metallic sample was characterized in TEM.

  14. Performance of a new Electron-Tracking Compton Camera under intense radiations from a water target irradiated with a proton beam

    NASA Astrophysics Data System (ADS)

    Matsuoka, Y.; Tanimori, T.; Kubo, H.; Takada, A.; Parker, J. D.; Mizumoto, T.; Mizumura, Y.; Iwaki, S.; Sawano, T.; Komura, S.; Kishimoto, T.; Oda, M.; Takemura, T.; Miyamoto, S.; Sonoda, S.; Tomono, D.; Miuchi, K.; Kabuki, S.; Kurosawa, S.

    2015-01-01

    We have developed an electron-tracking Compton camera (ETCC) for use in next-generation MeV gamma ray telescopes. An ETCC consists of a gaseous time projection chamber (TPC) and pixel scintillator arrays (PSAs). Since the TPC measures the three dimensional tracks of Compton-recoil electrons, the ETCC can completely reconstruct the incident gamma rays. Moreover, the ETCC demonstrates efficient background rejection power in Compton-kinematics tests, identifies particle from the energy deposit rate (dE/dX) registered in the TPC, and provides high quality imaging by completely reconstructing the Compton scattering process. We are planning the ``Sub-MeV gamma ray Imaging Loaded-on-balloon Experiment'' (SMILE) for our proposed all-sky survey satellite. Performance tests of a mid-sized (30 cm)3 ETCC, constructed for observing the Crab nebula, are ongoing. However, observations at balloon altitudes or satellite orbits are obstructed by radiation background from the atmosphere and the detector itself [1]. The background rejection power was checked using proton accelerator experiments conducted at the Research Center for Nuclear Physics, Osaka University. To create the intense radiation fields encountered in space, which comprise gamma rays, neutrons, protons, and other energetic entities, we irradiated a water target with a 140 MeV proton beam and placed a SMILE-II ETCC near the target. In this situation, the counting rate was five times than that expected at the balloon altitude. Nonetheless, the ETCC stably operated and identified particles sufficiently to obtain a clear gamma ray image of the checking source. Here, we report the performance of our detector and demonstrate its effective background rejection based in electron tracking experiments.

  15. 78 FR 27303 - Irradiation in the Production, Processing, and Handling of Animal Feed and Pet Food; Electron...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-10

    ... Feed and Pet Food; Electron Beam and X-Ray Sources for Irradiation of Poultry Feed and Poultry Feed... safe use of electron beam and x-ray sources for irradiation of poultry feed and poultry feed... CFR part 579) to provide for the safe use of electron beam and x-ray sources for irradiation of...

  16. Formation of microcraters and hierarchically-organized surface structures in TiNi shape memory alloy irradiated with a low-energy, high-current electron beam

    SciTech Connect

    Meisner, L. L. Meisner, S. N.; Markov, A. B. Ozur, G. E. Yakovlev, E. V.; Rotshtein, V. P.; Gudimova, E. Yu.

    2015-10-27

    The regularities of surface cratering in TiNi alloy irradiated with a low-energy, high-current electron beam (LEHCEB) in dependence on energy density and number of pulses are studied. LEHCEB processing of TiNi samples was carried out using RITM-SP facility. Energy density E{sub s} was varied from 1 to 5 J/cm{sup 2}, pulse duration was 2.5–3.0 μs, the number of pulses n = 1–128. The dominant role of non-metallic inclusions [mainly, TiC(O)] in the nucleation of microcraters was found. It was revealed that at small number of pulses (n = 2), an increase in energy density leads both to increasing average diameter and density of microcraters. An increase in the number of pulses leads to a monotonic decrease in density of microcraters, and, therefore, that of the proportion of the area occupied by microcraters, as well as a decrease in the surface roughness. The multiple LEHCEB melting of TiNi alloy in crater-free modes enables to form quasi-periodical, hierarchically-organized microsized surface structures.

  17. Compact electron beam focusing column

    SciTech Connect

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-07-13

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  18. Depressed collector for electron beams

    NASA Technical Reports Server (NTRS)

    Ives, R. Lawrence (Inventor)

    2005-01-01

    A depressed collector for recovery of spent beam energy from electromagnetic sources emitting sheet or large aspect ration annular electron beams operating aver a broad range of beam voltages and currents. The collector incorporates a trap for capturing and preventing the return of reflected and secondary electrons.

  19. Quantifying the Reduction in Potential Health Risks by Determining the Sensitivity of Poliovirus Type 1 Chat Strain and Rotavirus SA-11 to Electron Beam Irradiation of Iceberg Lettuce and Spinach

    PubMed Central

    Espinosa, Ana Cecilia; Jesudhasan, Palmy; Arredondo, René; Cepeda, Martha; Mazari-Hiriart, Marisa; Mena, Kristi D.

    2012-01-01

    Fresh produce, such as lettuce and spinach, serves as a route of food-borne illnesses. The U.S. FDA has approved the use of ionizing irradiation up to 4 kGy as a pathogen kill step for fresh-cut lettuce and spinach. The focus of this study was to determine the inactivation of poliovirus and rotavirus on lettuce and spinach when exposed to various doses of high-energy electron beam (E-beam) irradiation and to calculate the theoretical reduction in infection risks that can be achieved under different contamination scenarios and E-beam dose applications. The D10 value (dose required to reduce virus titers by 90%) (standard error) of rotavirus on spinach and lettuce was 1.29 (± 0.64) kGy and 1.03 (± 0.05) kGy, respectively. The D10 value (standard error) of poliovirus on spinach and lettuce was 2.35 (± 0.20) kGy and 2.32 (± 0.08) kGy, respectively. Risk assessment of data showed that if a serving (∼14 g) of lettuce was contaminated with 10 PFU/g of poliovirus, E-beam irradiation at 3 kGy will reduce the risk of infection from >2 in 10 persons to approximately 6 in 100 persons. Similarly, if a serving size (∼0.8 g) of spinach is contaminated with 10 PFU/g of rotavirus, E-beam irradiation at 3 kGy will reduce infection risks from >3 in 10 persons to approximately 5 in 100 persons. The results highlight the value of employing E-beam irradiation to reduce public health risks but also the critical importance of adhering to good agricultural practices that limit enteric virus contamination at the farm and in packing houses. PMID:22179244

  20. Use of lactic acid with electron beam irradiation for control of Escherichia coli O157:H7, non-O157 VTEC E. coli, and Salmonella serovars on fresh and frozen beef.

    PubMed

    Li, Shuliu; Kundu, Devapriya; Holley, Richard A

    2015-04-01

    Lactic acid pre-treatment was examined to enhance the antimicrobial action of electron (e-) beam irradiation of beef trim. Meat samples were inoculated with Escherichia coli O157:H7, non-O157 VTEC E. coli or Salmonella cocktails and treated with 5% lactic acid at 55 °C. Samples were packaged aerobically or vacuum-packed, kept at 4 °C and treated with 1 kGy e-beam energy. Frozen samples were treated with 1, 3 or 7 kGy and stored at -20 °C for ≤ 5 d. Lactic acid enhanced the antimicrobial action of 1 kGy e-beam treatment against Salmonella by causing an additional <1.8 log CFU/g reduction. One kGy treatment of refrigerated samples reduced VTEC E. coli viability by 4.5 log CFU/g, and while lactic acid did not improve the reduction, after freezing additive effects were found. After 3 kGy irradiation, Salmonella was reduced by 2 and 4 log CFU/g in the irradiated and lactic acid plus irradiated samples, respectively. Lactic acid pre-treatment was of limited value with 1 kGy treatment for improving control of toxigenic E. coli in fresh beef trim, however, it would be useful with low dose irradiation for controlling both VTEC E. coli and Salmonella in frozen product. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Semiconductor diode characterization for total skin electron irradiation.

    PubMed

    Madrid González, O A; Rivera Montalvo, T

    2014-01-01

    In this paper, a semiconductor diode characterization was performed. The diode characterization was completed using an electron beam with 4 MeV of energy. The semiconductor diode calibration used irradiation with an electron beam in an ion chamber. "In vivo" dosimetry was also conducted. The dosimetry results revealed that the semiconductor diode was a good candidate for use in the total skin electron therapy (TSET) treatment control.

  2. Electron beam induced growth of tin whiskers

    SciTech Connect

    Vasko, A. C.; Karpov, V. G.; Warrell, G. R.; Parsai, E. I.; Shvydka, Diana

    2015-09-28

    We have investigated the influence of electron irradiation on tin whisker growth. Sputtered tin samples exposed to electron beam of 6 MeV energy exhibited fast whisker growth, while control samples did not grow any whiskers. The statistics of e-beam induced whiskers was found to follow the log-normal distribution. The observed accelerated whisker growth is attributed to electrostatic effects due to charges trapped in an insulating substrate. These results offer promise for establishing whisker-related accelerated life testing protocols.

  3. Visible cathodoluminescence of quantum dot films by direct irradiation of electron beam and its materialization as a field emission device.

    PubMed

    Woo, Ju Yeon; Lee, Jongsoo; Lee, Hansung; Lee, Naesung; Oh, Ji Hye; Do, Young Rag; Han, Chang-Soo

    2013-05-20

    The field emission (FE) device based on quantum dot (QD) films as a cathodoluminescent (CL) material has not emerged yet due to the relatively low quantum efficiency and weak photostability of nanocrystals (NCs). Here we improve film stability and luminescence yields by preparing neat films of well-packed core-multishell QDs using spray coating method and then using low-temperature atomic layer deposition (ALD) to infill the pores of these films with metal oxides to produce inorganic nanocomposites. The ALD coatings to protect oxidation and degradation by electrons prevent internal atomic and molecular diffusion and decrease surface trap densities of QD films. Furthermore, the CL of the core-multishell QD films is 2.4 times higher than before ALD infilling. We fabricate the FE device by combining cathode structure with carbon nanotube (CNT) emitters and anode plates with QD thin film and successfully can get brilliant images of the light-emitting FE device. Our research opens a way for developing new quantum optoelectronics with high-performance.

  4. Pulsed electron beam precharger

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    Florida State University is investigating the concept of pulsed electron beams for fly ash precipitation. This report describes the results and data on three of the subtasks of this project and preliminary work only on the remaining five subtasks. Described are the modification of precharger for pulsed and DC energization of anode; installation of the Q/A measurement system; and modification and installation of pulsed power supply to provide both pulsed and DC energization of the anode. The other tasks include: measurement of the removal efficiency for monodisperse simulated fly ash particles; measurement of particle charge; optimization of pulse energization schedule for maximum removal efficiency; practical assessment of results; and measurement of the removal efficiency for polydisperse test particles. 15 figs., 1 tab. (CK)

  5. Pyroelectric-field driven defects diffusion along c-axis in ZnO nanobelts under high-energy electron beam irradiation

    SciTech Connect

    Ding, Yong Liu, Ying; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

    2014-10-21

    When ZnO nanobelts are exposed to a high-dose electron probe of several nanometers to hundred nanometers in diameter inside a transmission electron microscope, due to the radiolysis effect, part of oxygen atoms will be ejected into the vacuum and leaving a Zn-ion rich surface with a pit appearance at both the electron-entrance and electron-exit surfaces. At the same time, a temperature distribution is created around the electron probe due to local beam heating effect, which generates a unidirectional pyroelectric field. This pyroelectric field is strong enough to drive Zn ions moving along its positive c-axis direction as interstitial ions. In the first case, for the ZnO nanobelts with c-axis lie in their large surfaces, defects due to the aggregation of Zn interstitial ions will be formed at some distances of 30–50 nm approximately along the c-axis direction from the electron beam illuminated area. Alternatively, for the ZnO nanobelts with ±(0001) planes as their large surfaces, the incident electron beam is along its c-axis and the generated pyroelectric field will drive the interstitial Zn-ions to aggregate at the Zn terminated (0001) surface where the local electrical potential is the lowest. Such electron beam induced damage in ZnO nanostructures is suggested as a result of Zn ion diffusion driven by the temperature gradient induced pyroelectric field along c-axis. Our study shows a radiation damage caused by electron beam in transmission electron microscopy, especially when the electron energy is high.

  6. Impact of electron irradiation on electron holographic potentiometry

    SciTech Connect

    Park, J. B.; Niermann, T.; Lehmann, M.; Berger, D.; Knauer, A.; Weyers, M.; Koslow, I.; Kneissl, M.

    2014-09-01

    While electron holography in the transmission electron microscope offers the possibility to measure maps of the electrostatic potential of semiconductors down to nanometer dimensions, these measurements are known to underestimate the absolute value of the potential, especially in GaN. We have varied the dose rates of electron irradiation over several orders of magnitude and observed strong variations of the holographically detected voltages. Overall, the results indicate that the electron beam generates electrical currents within the specimens primarily by the photovoltaic effect and due to secondary electron emission. These currents have to be considered for a quantitative interpretation of electron holographic measurements, as their negligence contributes to large parts in the observed discrepancy between the measured and expected potential values in GaN.

  7. Comparison of gamma and electron beam irradiation in reducing populations of E. coli artificially inoculated on mung bean, clover and fenugreek seeds, and affecting germination and growth of seeds

    NASA Astrophysics Data System (ADS)

    Fan, Xuetong; Sokorai, Kimberly; Weidauer, André; Gotzmann, Gaby; Rögner, Frank-Holm; Koch, Eckhard

    2017-01-01

    Sprouts have frequently been implicated in outbreaks of foodborne illnesses, mostly due to contaminated seeds. Intervention technologies to decontaminate seeds without affecting sprout yield are needed. In the present study, we compared gamma rays with electron beam in inactivating E. coli artificially inoculated on three seeds (fenugreek, clover and mung bean) that differed in size and surface morphology. Furthermore, the germination and growth of irradiated seeds were evaluated. Results showed that the D10 values (dose required to achieve 1 log reduction) for E. coli K12 on mung bean, clover, and fenugreek were 1.11, 1.21 and 1.40 kGy, respectively. To achieve a minimum 5-log reduction of E. coli, higher doses were needed on fenugreek than on mung bean or clover. Electron beam treatment at doses up to 12 kGy could not completely inactivate E. coli inoculated on all seeds even though most of the seeds were E. coli-free after 4-12 kGy irradiation. Gamma irradiation at doses up to 6 kGy did not significantly affect the germination rate of clover and fenugreek seeds but reduced the germination rate of mung bean seeds. Doses of 2 kGy gamma irradiation did not influence the growth of seeds while higher doses of gamma irradiation reduced the growth rate. Electron beam treatment at doses up to 12 kGy did not have any significant effect on germination or growth of the seeds. SEM imaging indicated there were differences in surface morphology among the three seeds, and E. coli resided in cracks and openings of seeds, making surface decontamination of seeds with low energy electron beam a challenge due to the low penetration ability. Overall, our results suggested that gamma rays and electron beam had different effects on E. coli inactivation and germination or growth of seeds. Future efforts should focus on optimization of electron bean parameters to increase penetration to inactivate E. coli without causing damage to the seeds.

  8. Electron Beam Diagnostics in Plasmas Based on Electron Beam Ionization

    NASA Astrophysics Data System (ADS)

    Leonhardt, Darrin; Leal-Quiros, Edbertho; Blackwell, David; Walton, Scott; Murphy, Donald; Fernsler, Richard; Meger, Robert

    2001-10-01

    Over the last few years, electron beam ionization has been shown to be a viable generator of high density plasmas with numerous applications in materials modification. To better understand these plasmas, we have fielded electron beam diagnostics to more clearly understand the propagation of the beam as it travels through the background gas and creates the plasma. These diagnostics vary greatly in sophistication, ranging from differentially pumped systems with energy selective elements to metal 'hockey pucks' covered with thin layers of insulation to electrically isolate the detector from the plasma but pass high energy beam electrons. Most importantly, absolute measurements of spatially resolved beam current densities are measured in a variety of pulsed and continuous beam sources. The energy distribution of the beam current(s) will be further discussed, through experiments incorporating various energy resolving elements such as simple grids and more sophisticated cylindrical lens geometries. The results are compared with other experiments of high energy electron beams through gases and appropriate disparities and caveats will be discussed. Finally, plasma parameters are correlated to the measured beam parameters for a more global picture of electron beam produced plasmas.

  9. Prevention of electron beam transmittance for biological cell imaging using electron beam excitation-assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Fukuta, Masahiro; Nawa, Yasunori; Inami, Wataru; Kawata, Yoshimasa

    2016-12-01

    We demonstrated the high-spatial-resolution imaging of label-free biological cells using an electron beam excitation-assisted optical (EXA) microscope without irradiation damage by the electron beam. An EXA microscope can be used to observe a specimen with a nanometric light source excited in the Si3N4 membrane by an electron beam. The incident electron beam penetrates the Si3N4 membrane and damages the specimen. To suppress the irradiation damage of the specimen, we prevented the transmittance of the electron beam by coating the Si3N4 membrane with a gold thin film. To obtain an electron beam transmittance through the Si3N4 of 0%, a gold film of 15 nm thickness was required. By adding the gold layer, a label-free cellular structure was observed with 135-nm spatial resolution.

  10. Prevention of electron beam transmittance for biological cell imaging using electron beam excitation-assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Fukuta, Masahiro; Nawa, Yasunori; Inami, Wataru; Kawata, Yoshimasa

    2017-04-01

    We demonstrated the high-spatial-resolution imaging of label-free biological cells using an electron beam excitation-assisted optical (EXA) microscope without irradiation damage by the electron beam. An EXA microscope can be used to observe a specimen with a nanometric light source excited in the Si3N4 membrane by an electron beam. The incident electron beam penetrates the Si3N4 membrane and damages the specimen. To suppress the irradiation damage of the specimen, we prevented the transmittance of the electron beam by coating the Si3N4 membrane with a gold thin film. To obtain an electron beam transmittance through the Si3N4 of 0%, a gold film of 15 nm thickness was required. By adding the gold layer, a label-free cellular structure was observed with 135-nm spatial resolution.

  11. Surface, structural and tensile properties of proton beam irradiated zirconium

    NASA Astrophysics Data System (ADS)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo

    2016-02-01

    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 1013 to 1 × 1016 protons/cm2. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples' surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson-Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  12. Comparison of crystal growth and thermoelectric properties of n-type Bi-Se-Te and p-type Bi-Sb-Te nanocrystalline thin films: Effects of homogeneous irradiation with an electron beam

    SciTech Connect

    Takashiri, Masayuki Imai, Kazuo; Uyama, Masato; Nishi, Yoshitake; Hagino, Harutoshi; Miyazaki, Koji; Tanaka, Saburo

    2014-06-07

    The effects of homogenous electron beam (EB) irradiation on the crystal growth and thermoelectric properties of n-type Bi-Se-Te and p-type Bi-Sb-Te thin films were investigated. Both types of thin films were prepared by flash evaporation, after which homogeneous EB irradiation was performed at an acceleration voltage of 0.17 MeV. For the n-type thin films, nanodots with a diameter of less than 10 nm were observed on the surface of rice-like nanostructures, and crystallization and crystal orientation were improved by EB irradiation. The resulting enhancement of mobility led to increased electrical conductivity and thermoelectric power factor for the n-type thin films. In contrast, the crystallization and crystal orientation of the p-type thin films were not influenced by EB irradiation. The carrier concentration increased and mobility decreased with increased EB irradiation dose, possibly because of the generation of defects. As a result, the thermoelectric power factor of p-type thin films was not improved by EB irradiation. The different crystallization behavior of the n-type and p-type thin films is attributed to atomic rearrangement during EB irradiation. Selenium in the n-type thin films is more likely to undergo atomic rearrangement than the other atoms present, so only the crystallinity of the n-type Bi-Se-Te thin films was enhanced.

  13. 77 FR 12226 - Sadex Corp.; Filing of Food Additive Petition (Animal Use); Electron Beam and X-Ray Sources for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... Petition (Animal Use); Electron Beam and X-Ray Sources for Irradiation of Poultry Feed and Poultry Feed... regulations be amended to provide for the safe use of electron beam and x-ray sources for irradiation of... use of electron beam and x- ray sources for irradiation of poultry feed and poultry feed ingredients...

  14. Electron beam irradiation of cellulose

    NASA Astrophysics Data System (ADS)

    Driscoll, Mark; Stipanovic, Arthur; Winter, William; Cheng, Kun; Manning, Mellony; Spiese, Jessica; Galloway, Richard A.; Cleland, Marshall R.

    2009-07-01

    Using a 90 kW, 3 MeV Dynamitron™, the molecular weight of microcrystalline cellulose (MCC) was reduced from 82,000 to 5000 Da with a dose of 100 kGy. The relative crystallinity of the MCC was reduced from 87% to 45% with a dose of 1000 kGy. The available surface area, an indication on how well cellulose will react with chemical agents, was increased from 274 m 2/g for the control sample (0 kGy) to 318 m 2/g at a dose 1000 kGy.

  15. Electron-beam distillation of natural polymers

    NASA Astrophysics Data System (ADS)

    Ponomarev, A. V.; Makarov, I. E.; Ershov, B. G.

    2014-01-01

    Pyrolysis of cellulose, lignin, and chitin may be upgraded by the use of an electron-beam irradiation. The radiation-thermal destruction mode does more probable production of liquid low-molecular-weight products instead of solid pyrolitic oligomers. Furans, methoxyphenols, and pyridines are dominant products of high-temperature radiolysis of cellulose, lignin, and chitin, respectively. The mechanism of chain destruction of natural polymers is considered.

  16. Temperature measurements during high flux ion beam irradiations

    SciTech Connect

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; Weber, William J.

    2016-02-16

    A systematic study of the ion beam heating effect was performed in a temperature range of –170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm–2 s–1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. Furthermore, a simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beamanalysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.

  17. Temperature measurements during high flux ion beam irradiations

    DOE PAGES

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; ...

    2016-02-16

    A systematic study of the ion beam heating effect was performed in a temperature range of –170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm–2 s–1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggestsmore » that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. Furthermore, a simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beamanalysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.« less

  18. Determination of free cholesterol oxide products in food samples by gas chromatography and accelerated solvent extraction: influence of electron-beam irradiation on cholesterol oxide formation.

    PubMed

    Lozada-Castro, Juan José; Santos-Delgado, María Jesús; Polo-Díez, Luis María

    2016-09-01

    The aim of this study was to develop an efficient method for cholesterol oxide product (COP) determination in irradiated and non-irradiated ready-to-eat foods with high water content by gas chromatography-flame ionisation detector after accelerated solvent extraction (ASE), and derivatisation with a silylating reagent. The ASE solvent was an 85:15 v/v petroleum ether/chloroform mixture at 40 °C and 1500 psi followed by solid phase extraction. The ASE method was compared with the established lixiviation method, proving an advantageous alternative which reduces analysis time by a factor of 15 and solvent volume by 50%, and minimises the use of chlorinated solvents. COP derivative structures were identified by gas chromatography coupled with mass spectrometry. Analytical characteristics were determined from standards and recoveries were 63-95%, establishing the validity of the method. The results obtained and their analysis by chemometric techniques established COP formation in food samples after e-beam irradiation. Increase in COP concentration depended on both irradiation doses and food composition, mainly water and fat content, although linear correlations among variables were not found. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  19. SU-E-T-556: Monte Carlo Generated Dose Distributions for Orbital Irradiation Using a Single Anterior-Posterior Electron Beam and a Hanging Lens Shield

    SciTech Connect

    Duwel, D; Lamba, M; Elson, H; Kumar, N

    2015-06-15

    Purpose: Various cancers of the eye are successfully treated with radiotherapy utilizing one anterior-posterior (A/P) beam that encompasses the entire content of the orbit. In such cases, a hanging lens shield can be used to spare dose to the radiosensitive lens of the eye to prevent cataracts. Methods: This research focused on Monte Carlo characterization of dose distributions resulting from a single A-P field to the orbit with a hanging shield in place. Monte Carlo codes were developed which calculated dose distributions for various electron radiation energies, hanging lens shield radii, shield heights above the eye, and beam spoiler configurations. Film dosimetry was used to benchmark the coding to ensure it was calculating relative dose accurately. Results: The Monte Carlo dose calculations indicated that lateral and depth dose profiles are insensitive to changes in shield height and electron beam energy. Dose deposition was sensitive to shield radius and beam spoiler composition and height above the eye. Conclusion: The use of a single A/P electron beam to treat cancers of the eye while maintaining adequate lens sparing is feasible. Shield radius should be customized to have the same radius as the patient’s lens. A beam spoiler should be used if it is desired to substantially dose the eye tissues lying posterior to the lens in the shadow of the lens shield. The compromise between lens sparing and dose to diseased tissues surrounding the lens can be modulated by varying the beam spoiler thickness, spoiler material composition, and spoiler height above the eye. The sparing ratio is a metric that can be used to evaluate the compromise between lens sparing and dose to surrounding tissues. The higher the ratio, the more dose received by the tissues immediately posterior to the lens relative to the dose received by the lens.

  20. Generation of electron Airy beams.

    PubMed

    Voloch-Bloch, Noa; Lereah, Yossi; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-02-21

    Within the framework of quantum mechanics, a unique particle wave packet exists in the form of the Airy function. Its counterintuitive properties are revealed as it propagates in time or space: the quantum probability wave packet preserves its shape despite dispersion or diffraction and propagates along a parabolic caustic trajectory, even though no force is applied. This does not contradict Newton's laws of motion, because the wave packet centroid propagates along a straight line. Nearly 30 years later, this wave packet, known as an accelerating Airy beam, was realized in the optical domain; later it was generalized to an orthogonal and complete family of beams that propagate along parabolic trajectories, as well as to beams that propagate along arbitrary convex trajectories. Here we report the experimental generation and observation of the Airy beams of free electrons. These electron Airy beams were generated by diffraction of electrons through a nanoscale hologram, which imprinted on the electrons' wavefunction a cubic phase modulation in the transverse plane. The highest-intensity lobes of the generated beams indeed followed parabolic trajectories. We directly observed a non-spreading electron wavefunction that self-heals, restoring its original shape after passing an obstacle. This holographic generation of electron Airy beams opens up new avenues for steering electronic wave packets like their photonic counterparts, because the wave packets can be imprinted with arbitrary shapes or trajectories.

  1. Electron-beam direct processing on living cell membrane

    SciTech Connect

    Hoshino, Takayuki; Morishima, Keisuke

    2011-10-24

    We demonstrated a direct processing on a living Hep G2 cell membrane in conventional cultivation conditions using an electron beam. Electron beam-induced deposition from liquid precursor 3,4-ethylenedioxythiophene and ablation was performed on the living cells. The 2.5-10 keV electron beam which was irradiated through a 100-nm-thick SiN nanomembrane could induce a deposition pattern and a ablation on a living cell membrane. This electron beam direct processing can provide simple in-situ cell surface modification for an analytical method of living cell membrane dynamic.

  2. Application of ``electronika 10 - 10'' electron linac for food irradiation

    NASA Astrophysics Data System (ADS)

    Migdał, W.; Maciszewski, W.; Gryzlow, A.

    1995-02-01

    The industrial electron linac "Elektronika 10 - 10" has been installed in Experimental Plant for Food Irradiation (INCT) in 1990. The accelerator is a prototype unit, prior the use for food treatment a period of optimization was involved in its experimental operation during 1993. The accelerator is capable to produce scanned beam of electrons with the energy 10 MeV and beam power of 10 kW. Radiation dose at minimal conveyer speed of 0.25 m/min reaches 50 kGy. The role of the plant is to promote food irradiation in Poland.

  3. Electron beams in solar flares

    NASA Technical Reports Server (NTRS)

    Aschwanden, Markus J.; Dennis, Brian R.; Benz, Arnold O.

    1994-01-01

    A list of publications resulting from this program includes 'The Timing of Electron Beam Signatures in Hard X-Ray and Radio: Solar Flare Observations by BATSE/Compton Gamma-Ray Observatory and PHOENIX'; 'Coherent-Phase or Random-Phase Acceleration of Electron Beams in Solar Flares'; 'Particle Acceleration in Flares'; 'Chromospheric Evaporation and Decimetric Radio Emission in Solar Flares'; 'Sequences of Correlated Hard X-Ray and Type 3 Bursts During Solar Flares'; and 'Solar Electron Beams Detected in Hard X-Rays and Radiowaves.' Abstracts and reprints of each are attached to this report.

  4. Surface characterization of poly(N-isopropylacrylamide) grafted tissue culture polystyrene by electron beam irradiation, using atomic force microscopy, and X-ray photoelectron spectroscopy.

    PubMed

    Akiyama, Yoshikatsu; Kushida, Ai; Yamato, Masayuki; Kikuchi, Akihiko; Okano, Teruo

    2007-03-01

    To understand features of polymers grafted by electron beam (EB) irradiation method, we investigated topology of poly(N-isopropylacrylamide) (PIPAAm) grafted tissue culture polystyrene (TCPS) (PIPAAm-TCPS) prepared by EB irradiation, using atomic force microscopy (AFM) in air and under aqueous conditions. Furthermore, surfaces properties of PIPAAm-TCPS surfaces before and after cell culture were also examined for evaluation of functionality of the surface as biomaterials, using XPS analysis. Three types of PIPAAm-TCPSs with different graft densities (1.0+/-0.1, 1.6+/-0.1, and 2.0+/-0.1 microg/cm2 of the grafted) were obtained (abbreviated as 11PIPAAm-, 16PIPAAm-, and 20PIPAAm-TCPS) by using different initial monomer concentration (20, 55, and 65 wt%). Contact angles (costheta value) of the surfaces increased with an increase in density of the grafted polymer. AFM observation in air clearly revealed that original TCPS surface possesses scratched and grooved topology (ca. 10 nm height of the scratch), while PIPAAm-TCPSs surfaces exhibited nanoordered PIPAAm particle-like domains. The size of the particles also increased proportionally initial IPAAm monomer concentration. The 11PIPAAm-and 16PIPAAm-TCPS surfaces having ca. 10-30 nm and ca. 40-50 nm size of the particles also displayed scratched and grooved topology featured in basal TCPS. However, the larger sizes of the particles (ca. 40-100 nm) formed on 20PIPAAm-TCPS surfaces adequately conceals the topological feature of the basal TCPS surfaces. The AFM images indicate that the graft polymer is as ultra thin as the scratch and grooves featured on basal TCPS are discernible, and the grafted PIPAAm layer become thicker with an increase of the monomer concentration. For 16PIPAAm-TCPS surfaces, the nanoordered particles were also observable in aqueous conditions at 20 degrees C and 37 degrees C. Comparison between the images obtained at 20 degrees C and 37 degrees C suggest that the domains are not likely to exhibit

  5. Electron beam pretreatment of sewage sludge before anaerobic digestion.

    PubMed

    Shin, Kyung-Sook; Kang, Ho

    2003-01-01

    The pretreatment of waste-activated sludge (WAS) by electron beam irradiation was studied in order to improve anaerobic sludge digestion. The irradiation dose of the electron beam was varied from 0.5 to 10 kGy. Batch and continuous-flow stirred tank reactors (CFSTRs) were operated to evaluate the effect of the electron beam pretreatment on anaerobic sludge digestion. Approximately 30-52% of the total chemical oxygen demand (COD) content of the WAS was solubilized within 24 h after electron beam irradiation. A large quantity of soluble COD, protein, and carbohydrates leached out from cell ruptures caused by the electron beam irradiation. Volatile fatty acids production from the irradiated sludge was approx 90% higher than that of the unirradiated sludge. The degradation of irradiated sewage sludge was described by two distinct first-order decay rates (k1 and k2). Most initial decay reaction accelerated within 10 d, with an average k1 of 0.06/d for sewage sludge irradiated at all dosages. The mean values for the long-term batch first-order decay coefficient (k2) were 0.025/d for irradiated sewage sludge and 0.007/d for unirradiated sludge. Volatile solids removal efficiency of the control reactor fed with unirradiated sewage sludge at a hydraulic retention time (HRT) of 20 d was almost the same as that of the CFSTRs fed with irradiated sludge at an HRT of 10 d. Therefore, disintegration of sewage sludge cells using electron beam pretreatment could reduce the reactor solid retention time by half.

  6. Dose controlled low energy electron irradiator for biomolecular films

    SciTech Connect

    Kumar, S. V. K. Tare, Satej T.; Upalekar, Yogesh V.; Tsering, Thupten

    2016-03-15

    We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at −20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.

  7. Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

    NASA Astrophysics Data System (ADS)

    Ramli, Syuhada; Ratnam, C. T.; Ahmad, S. H.; Athirah, Nurul

    2013-11-01

    The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancement of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔHf and crystallinity percentage decrease at higher PEgMAH content.

  8. Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

    SciTech Connect

    Ramli, Syuhada; Ahmad, S. H.; Ratnam, C. T.; Athirah, Nurul

    2013-11-27

    The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancement of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔH{sub f} and crystallinity percentage decrease at higher PEgMAH content.

  9. Theory and simulation of high-brightness electron beam production from laser-irradiated photocathodes in the presence of dc and RF electric fields

    NASA Astrophysics Data System (ADS)

    Jones, M. E.; Peter, W.

    1986-05-01

    To take advantage of properties of laser-controlled photodiodes to produce electron beams, a new set of diode design criteria are needed. An analytical and numerical study of the geometrical and temporal factors that affect the design of high-brightness electron beams is presented. This study extends our previous work on this concept to include the effects of laser pulse shape, and emittance effects in the presence of RF fields. In general, the diode will not be space-charge limited. Therefore, the conventional Pierce electrode shapes are not appropriate. Furthermore, the finite temporal profile of the electron beams introduces a time-dependent space charge into the design problem. The approach taken here to minimize the emittance growth from the temporal profile of the space charge is to operate at low perveance. To obtain high currents, large electric fields are required. We exploit the fact that the electron emission is controlled by the laser and is independent of the voltage on the diode. The diode can then be driven by an rf field. In principle, operating at higher frequency al lows higher breakdown limits, so the perveance can be made very small. However, operating at too high an RF frequency introduces other detrimental effects.

  10. Improved electron-beam welder

    NASA Technical Reports Server (NTRS)

    Smock, R. A.; Taylor, R. A.; Wall, W. A.

    1978-01-01

    Report describes comprehensive test-and-evaluation program designed to improve performance of 7.5 kW electron-beam welder. Report describes prototype and seventeen changes incorporated to improve performance.

  11. Repetitively pumped electron beam device

    DOEpatents

    Schlitt, L.G.

    1979-07-24

    Disclosed is an apparatus for producing fast, repetitive pulses of controllable length of an electron beam by phased energy storage in a transmission line of length matched to the number of pulses and specific pulse lengths desired. 12 figs.

  12. Susceptor heating device for electron beam brazing

    DOEpatents

    Antieau, Susan M.; Johnson, Robert G. R.

    1999-01-01

    A brazing device and method are provided which locally apply a controlled amount of heat to a selected area, within a vacuum. The device brazes two components together with a brazing metal. A susceptor plate is placed in thermal contact with one of the components. A serrated pedestal supports the susceptor plate. When the pedestal and susceptor plate are in place, an electron gun irradiates an electron beam at the susceptor plate such that the susceptor plate is sufficiently heated to transfer heat through the one component and melt the brazing metal.

  13. Surface modification by electron irradiation for improved immunoassay

    NASA Astrophysics Data System (ADS)

    Safrany, Agnes; Deelder, André

    1999-08-01

    Polystyrene microtitration (ELISA) plates modified by electron beam irradiation were used for a monoclonal antibody based sandwich immunoassay for quantitation of circulating anodic antigen levels in Schistosoma-infected individuals. The plates irradiated with 15 kGy showed 2-4-fold lower detection level compared to untreated plates, and a 10-fold lower antibody coating concentration than usually used was still detectable. These results were reproducible and the modified surfaces were stable even after 2 years when kept at room temperature.

  14. The effect of electron beam irradiation on the survival of Salmonella enterica serovar typhimurium and psychrotrophic bacteria on raw chicken breasts stored at four degrees celsius for fourteen days.

    PubMed

    Sarjeant, K C; Williams, S K; Hinton, A

    2005-06-01

    The effect of high-energy electron beam irradiation on the survival of Salmonella enterica serovar Typhimurium and psychrotrophic bacteria on commercial chicken breast meat was evaluated. Fresh chicken breast meat was purchased from a local poultry processor, inoculated with 8 log10 cfu/mL Salmonella, packaged in Styrofoam trays and over wrapped with a polyvinyl chloride film, and subjected to 0, 1, 2, or 3 kGy of irradiation. The packaged samples were stored at 4 degrees C and analyzed for Salmonella Typhimurium and psychrotrophic organisms at 0, 2, 4, 6, 8, 10, 12, and 14 d of storage. Direct plating and enrichment methods were used for S. Typhimurium analyses. The direct plating method revealed a 4 log reduction in Salmonella for chicken breasts inoculated and treated with 1, 2, or 3 kGy of irradiation. Psychrotrophic counts were conducted at 7 degrees C for 10 d and 25 degrees C for 5 d to determine the effect of incubation methods on the recovery of psychrotrophic organisms. The enrichment method resulted in the repair of injured Salmonella cells and an elevated Salmonella Typhimurium count for all irradiation dosages when compared with data reported for the direct plating method. In general, psychrotrophic counts increased as storage time increased. However, psychrotrophic counts decreased (P < 0.05) as the irradiation dosage increased.

  15. Surface alloying by ion, electron and laser beams

    SciTech Connect

    Rehn, L.E.; Picraux, S.T.; Wiedersich, H.

    1986-01-01

    This book presents the papers given at a conference on the surface treatments of alloys using ion, electron, and laser beams. Topics considered at the conference included energy deposition, heat flow, rapid solidification, physical radiation effects, ion implantation, ion-irradiated materials, microstructure, solute redistribution, surface-melted alloys, solute trapping in ion-implanted metals, and the industrial applications of ion beam processes.

  16. Dual-Cathode Electron-Beam Source

    NASA Technical Reports Server (NTRS)

    Bradley, James G.; Conley, Joseph M.; Wittry, David B.

    1988-01-01

    Beam from either cathode electromagnetically aligned with exit port. Electron beam from either of two cathodes deflected by magnetic and electric fields to central axis. Mechanical alignment of beam easy because cathode axes, anode apertures, and electron trajectories coplanar. Applications where uninterrupted service needed: scanning electron microscopes, transmission electron microscopes, electron-beam lithography equipment, Auger instruments, and microfocused x-ray sources.

  17. Effect of xenon on the structural phase state of the surface layer of cemented carbide under pulsed electron-beam irradiation

    SciTech Connect

    Ovcharenko, Vladimir E.; Ivanov, Yurii F.; Mohovikov, Alexey A.; Baohai, Yu Cai, Xiaolong Zhong, Lisheng Xu, Yunhua

    2015-10-27

    A comparative analysis of the surface-layer microstructure of a tungsten-based cemented carbide modified with pulsed high-energy electron beams generated by gas-discharge plasmas and of the tool life of metal-cutting plates prepared from this alloy is performed. The choice of a plasma-forming gas providing for the emission of electrons out of the plasma-filled cathode is shown to have a profound influence both on the formation process of nano-sized structural-phase states in the surface layer of the cemented carbide and on the tool life of the metal-cutting plates prepared from this alloy.

  18. Effect of xenon on the structural phase state of the surface layer of cemented carbide under pulsed electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Ovcharenko, Vladimir E.; Ivanov, Yurii F.; Mohovikov, Alexey A.; Baohai, Yu; Cai, Xiaolong; Zhong, Lisheng; Xu, Yunhua

    2015-10-01

    A comparative analysis of the surface-layer microstructure of a tungsten-based cemented carbide modified with pulsed high-energy electron beams generated by gas-discharge plasmas and of the tool life of metal-cutting plates prepared from this alloy is performed. The choice of a plasma-forming gas providing for the emission of electrons out of the plasma-filled cathode is shown to have a profound influence both on the formation process of nano-sized structural-phase states in the surface layer of the cemented carbide and on the tool life of the metal-cutting plates prepared from this alloy.

  19. Mutation induced with ion beam irradiation in rose

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; 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.

  20. Temperature dependence of electron-beam induced effects in amorphous apatite

    SciTech Connect

    Bae, In-Tae; Zhang, Yanwen; Weber, William J.; Ishimaru, Manabu; Hirotsu, Yoshihiko; Higuchi, Mikio

    2008-06-07

    Irradiation effects on pre-amorphized Sr2Nd8(SiO4)6O2 have been investigated under 200 and 300 keV electron-beam irradiation at 130 and 480 K using in situ transmission electron microscopy. At 480 K, recrystallization occurred from the amorphous/crystalline interface under both 200 and 300 keV e-beam irradiation. At 130 K, the 200 keV e-beam irradiation induced recrystallization only; however, 300 keV e-beam irradiation induced both recrystallization and an electron hammering effect in the amorphous material that resulted in radial expansion perpendicular to the incident electron-beam direction and shrinkage parallel to the electron-beam direction. Ionization-induced processes and knock-on displacement damage are suggested to be the mechanisms for the recrystallization and the electron hammering effect, respectively.

  1. Microbial growth and sensory quality of dried potato slices irradiated by electrons

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Jin; Song, Hyeon-Jeong; Song, Kyung-Bin

    2011-06-01

    Electron beam irradiation was applied to secure the microbial safety of dried purple sweet potato. After purple sweet potato slices had been dehydrated with 20% (w/w) maltodextrin solution, the samples were irradiated at doses 2, 4, 6, 8, and 10 kGy and then stored at 20 °C for 60 days. Microbiological data indicated that the populations of total aerobic bacteria and of yeast and molds significantly decreased with increase in irradiation dosage. Specifically, microbial load was reduced by about three log cycles at 6 kGy compared to those of the control. Based on the color measurement of the potato slices, electron beam irradiation treatment did not affect the color quality. Sensory evaluation results also showed that electron beam irradiation did not affect overall sensory scores during storage. These results suggest that electron beam irradiation could be useful for improving microbial safety without impairing the quality of the potato slices during storage.

  2. Capillary liquid chromatography with diode array and mass spectrometry detection for heterocyclic aromatic amine determination in ready-to-eat food treated with electron-beam irradiation.

    PubMed

    Gonzalo-Lumbreras, R; Rosales-Conrado, N; León-González, M E; Pérez-Arribas, L V; Polo-Díez, L M

    2010-10-22

    In the present paper, we have developed a capillary liquid chromatography with MS detection for the determination at ngg⁻¹ levels of four heterocyclic aromatic amines (MeIQx, norharman, harman and harmine), a group of mutagenic and carcinogenic compounds that can potentially be produced in protein-rich food during processing operations. They have been determined in commercial ready-to-eat (RTE) smoked salmon and soft cheese treated with E-beam irradiation. On the basis of experimental design studies and operating conditions of MS detector, best chromatographic conditions were obtained using a Luna® C¹⁸ capillary column (150 mm × 0.3 mm I.D.) with a mixture of acetonitrile-ammonium formate 5 mM pH 3.6 buffer (13:87, v/v) as mobile phase. To improve sensitivity, large injection volumes (20 μL) and injection solutions of low elution strength were employed. Sample preparation procedure included a previous treatment with 1M NaOH, followed by two solid-phase extraction steps; firstly on diatomaceous earth and then on mixed-mode cartridges. Heterocyclic amines were detected neither in irradiated and in non-irradiated samples, indicating that they were not formed by the radiation effect even at doses higher than those indicated in the Food Safety Objective established by regulatory agencies. RTE food samples were spiked at concentration levels in the range 10-30 ngg⁻¹. Recoveries higher than 85% (n=3 for each spiked level) were obtained, showing the effectiveness of the proposed methodology.

  3. Electron beam pumped semiconductor laser

    NASA Technical Reports Server (NTRS)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)

    2009-01-01

    Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

  4. Relativistic Electron Beams Above Thunderclouds

    NASA Astrophysics Data System (ADS)

    Fullekrug, Martin; Roussel-Dupre, Robert; Symbalisty, Eugene; Chanrion, Olivier; van der Velde, Oscar; Soula, Serge; Odzimek, Anna; Bennett, Alec; Whitley, Toby; Neubert, Torsten

    2010-05-01

    It has recently been discovered that lightning discharges generate upward-directed relativistic electron beams above thunderclouds. This extends the phenomenon of relativistic runaway breakdown believed to occur inside thunderclouds to the atmosphere above thunderclouds. This marks a profound advance in our understanding of the atmosphere because we now know it acts as a giant, natural, particle accelerator. The accelerated electrons can reach significant relativistic energies of some MeV during their passage from the troposphere, through the middle atmosphere, into near-Earth space. These relativistic electron beams constitute a current above thunderclouds and effectively transfer energy from the troposphere to the middle atmosphere. This coupling process thereby forms a novel element of the global atmospheric electric circuit which links tropospheric thunderclouds to the atmosphere above. This contribution describes the radio remote sensing of upward electron beams to determine their occurrence frequency and to characterise their physical properites.

  5. Polarized electron beams at SLAC

    SciTech Connect

    Moffeit, K.C.

    1992-11-01

    SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e[plus]e[minus] collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point.

  6. Polarized electron beams at SLAC

    SciTech Connect

    Moffeit, K.C.

    1992-11-01

    SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e{plus}e{minus} collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point.

  7. Effectiveness of hydrogen peroxide and electron-beam irradiation treatment for removal and inactivation of viruses in equine-derived xenografts.

    PubMed

    Cusinato, Riccardo; Pacenti, Monia; Martello, Thomas; Fattori, Paolo; Morroni, Marco; Palù, Giorgio

    2016-06-01

    Bone grafting is a common procedure for bone reconstruction in dentistry, orthopedics, and neurosurgery. A wide range of grafts are currently used, and xenografts are regarded as an interesting alternative to autogenous bone because all mammals share the same bone mineral component composition and morphology. Antigens must be eliminated from bone grafts derived from animal tissues in order to make them biocompatible. Moreover, the processing method must also safely inactivate and/or remove viruses or other potential infectious agents. This study assessed the efficacy of two steps applied in manufacturing some equine-derived xenografts: hydrogen-peroxide and e-beam sterilization treatments for inactivation and removal of viruses in equine bone granules (cortical and cancellous) and collagen and pericardium membranes. Viruses belonging to three different human viral species (Herpes simplex virus type 1, Coxsackievirus B1, and Influenzavirus type A H1N1) were selected and used to spike semi-processed biomaterials. For each viral species, the tissue culture infective dose (TCID50) on cell lines and the number of genome copies through qPCR were assessed. Both treatments were found to be effective at virus inactivation. Considering the model viruses studied, the application of hydrogen peroxide and e-beam irradiation could also be considered effective for processing bone tissue of human origin. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Characterisation of dual ion beam irradiated yttria-stabilised zirconia by specific analytical techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwen; Wang, Xu; Liu, Shiyi; Tang, Meixiong; Zhao, Ziqiang

    2015-01-01

    The combined effect of dual ion beam irradiated yttria-stabilized zirconia was investigated through Rutherford backscattering spectrometry/channeling (RBS/C), high resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Compared with other experimental results of single ion beam irradiation, a multistep damage accumulation model can also explain the irradiation effects of dual ion beam. Irradiation damage created by Ar + He ions are simply additive and no synergy effect has been observed. The variation trends of step height and displacement damage are similar. The synergic effects of displacement damage between heavy recoil atoms and α-particle in nuclear waste matrices will not cause more serious damage than the sum of two kinds of ions. The two experimental damage peaks are consistent with those calculated using stopping and range of ions in matter (SRIM). Phase stability and irradiation resistance is further confirmed by high resolution transmission electron microscopy (HRTEM).

  9. Tailoring the properties of copper nanowires by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kumar, Narinder; Kumar, Rajesh; Kumar, Sushil; Chakarvarti, S. K.

    2016-02-01

    In the present paper, we investigated the change in the properties of copper nanowires under the irradiance of 80 MeV Si7+ ion beam. The nanowires were electrodeposited in the cylindrical pores of the track-etched polycarbonate membranes. The phase, morphology and optical absorbance of the fabricated nanowires were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible spectroscopy, respectively. The XRD study showed a face centered cubic crystal structure of copper nanowires. Further measurements with FESEM revealed that nanowires were continuous, aligned with uniform diameter having high aspect ratio. The XRD spectra of irradiated nanowires indicated an improved crystalinity at low ion fluences while it declines at higher ion fluences. The optical absorbance properties of the irradiated copper nanowires were also examined. The absorption spectra exhibited a peak at 568 nm which was attributed to the surface plasmon resonance. A significant increase in absorbance after irradiation accounts for the possibility of defects formation. The electrical properties measured from I-V characteristics showed an increase in resistivity of irradiated nanowires.

  10. Performance Evaluation Of An Irradiation Facility Using An Electron Accelerator

    SciTech Connect

    Uribe, R. M.; Hullihen, K.; Filppi, E.

    2011-06-01

    Irradiation parameters over a period of seven years have been evaluated for a radiation processing electron accelerator facility. The parameters monitored during this time were the electron beam energy, linearity of beam current, linearity of dose with the reciprocal value of the samples speed, and dose uniformity along the scanning area after a maintenance audit performed by the electron accelerator manufacturer. The electron energy was determined from the depth-dose curve by using a two piece aluminum wedge and measuring the practical range from the obtained curves. The linearity of dose with beam current, and reciprocal value of the speed and dose uniformity along the scanning area of the electron beam were determined by measuring the dose under different beam current and cart conveyor speed conditions using film dosimetry. The results of the experiments have shown that the energy in the range from 1 to 5 MeV has not changed by more than 15% from the High Voltage setting of the machine over the evaluation period, and dose linearity with beam current and cart conveyor speed has not changed. The dose uniformity along the scanning direction of the beam showed a dose uniformity of 90% or better for energies between 2 and 5 MeV, however for 1 MeV electrons this value was reduced to 80%. This parameter can be improved by changing the beam optics settings in the control console of the accelerator though.

  11. Electron beam ion source and electron beam ion trap (invited).

    PubMed

    Becker, Reinard; Kester, Oliver

    2010-02-01

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  12. Beam Studies with Electron Columns

    SciTech Connect

    Shiltsev, V.; Valishev, A.; Kuznetsov, G.; Kamerdzhiev, V.; Romanov, A.; /Novosibirsk, IYF

    2009-04-01

    We report preliminary results of experimental studies of 'electron columns' in the Tevatron and in a specialized test setup. In the Tevatron, a beam of 150 GeV protons ionizes residual gas and ionization electrons are stored in an electrostatic trap immersed into strong longitudinal magnetic field. Shifts of proton betatron frequencies are observed. In the test setup, we observe effects pointing to accumulation and escape of ionization electrons.

  13. Beam Characterizations at Femtosecond Electron Beam Facility

    SciTech Connect

    Rimjaem, S.; Jinamoon, V.; Kangrang, M.; Kusoljariyakul, K.; Saisut, J.; Thongbai, C.; Vilaithong, T.; Rhodes, M.W.; Wichaisirimongkol, P.; Wiedemann, H.; /SLAC

    2006-03-17

    The SURIYA project at the Fast Neutron Research Facility (FNRF) has been established and is being commissioning to generate femtosecond (fs) electron bunches. Theses short bunches are produced by a system consisting of an S-band thermionic cathode RF-gun, an alpha magnet (a-magnet) serving as a magnetic bunch compressor, and a SLAC-type linear accelerator (linac). The characteristics of its major components and the beam characterizations as well as the preliminary experimental results will be presented and discussed in this paper.

  14. Electron beam cutting

    DOEpatents

    Mochel, Margaret E.; Humphreys, Colin J.

    1985-04-02

    A method for the cutting of holes 20 Angstroms in diameter, or lines 20 Angstroms wide in a material having positive ionic conduction by the use of a focused electron probe is described. The holes and lines are stable under ambient conditions.

  15. Electron beam cutting

    DOEpatents

    Mochel, M.E.; Humphreys, C.J.

    1985-04-02

    A method for the cutting of holes 20 Angstroms in diameter, or lines 20 Angstroms wide in a material having positive ionic conduction by the use of a focused electron probe is described. The holes and lines are stable under ambient conditions. 2 figs.

  16. Shimmed electron beam welding process

    DOEpatents

    Feng, Ganjiang; Nowak, Daniel Anthony; Murphy, John Thomas

    2002-01-01

    A modified electron beam welding process effects welding of joints between superalloy materials by inserting a weldable shim in the joint and heating the superalloy materials with an electron beam. The process insures a full penetration of joints with a consistent percentage of filler material and thereby improves fatigue life of the joint by three to four times as compared with the prior art. The process also allows variable shim thickness and joint fit-up gaps to provide increased flexibility for manufacturing when joining complex airfoil structures and the like.

  17. New data on electron-beam purification of wastewater

    NASA Astrophysics Data System (ADS)

    Pikaev, A. K.

    2002-11-01

    Recent environmental applications of radiation technology, developed in the author's laboratory, are presented in this paper. They are electron-beam and coagulation purification of molasses distillery slops from distillery-produced ethyl alcohol by fermentation of plant materials, electron-beam purification of wastewater from carboxylic acids (for example, formic acid) and removal of petroleum products (diesel fuel, motor oil and residual fuel oil) from water by γ-irradiation.

  18. Flattening Filter Free vs Flattened Beams for Breast Irradiation

    SciTech Connect

    Spruijt, Kees H.; Dahele, Max; Cuijpers, Johan P.; Jeulink, Marloes; Rietveld, Derek; Slotman, Ben J.; Verbakel, Wilko F.A.R.

    2013-02-01

    Purpose: Flattening filter free (FFF) beams offer the potential for a higher dose rate, shorter treatment time, and lower peripheral dose. To investigate their role in large-field treatments, this study compared flattened and FFF beams for breast irradiation. Methods and Materials: Ten left breast clinical plans comprising 2 tangential beams and a medially located 3-field simultaneous integrated boost (SIB) were replanned. Full intensity modulated radiotherapy (IMRT), hybrid IMRT, electronic tissue compensator (ETC), and multiple static field treatment plans were created for the elective breast volume using flattened and FFF beams, in combination with a 3-field IMRT SIB. Plan quality was assessed and delivery times were measured for all plans for 1 patient. Out-of-field doses were measured using an ionization chamber for an IMRT plan optimized on a corner of simple cubic phantom for both flattened and FFF beams. Results: For each technique, mean target volume metrics (planning target volume coverage, homogeneity, conformity) were typically within 3% for flattened and FFF beams. Larger mean differences in boost conformity favoring flattened hybrid (7.2%) and full IMRT (5.5%) plans may have reflected limitations in plan normalization. Calculated heart and ipsilateral lung doses were comparable; however, both flattened and FFF low-dose phantom measurements were substantially higher than calculated values, rendering the comparison of low dose in the contralateral breast uncertain. Beam delivery times were on average 31% less for FFF. Conclusions: In general, target volume metrics for flattened and FFF plans were comparable. The planning system did not seem to allow for accurate peripheral dose evaluation. FFF was associated with a potentially shorter treatment time. All 4 IMRT techniques allowed FFF beams to generate acceptable plans for breast IMRT.

  19. Fowler-Nordheim characteristics of electron irradiated MOS capacitors

    SciTech Connect

    Candelori, A.; Paccagnella, A.; Cammarata, M.; Ghidini, G.; Fuochi, P.G.

    1998-12-01

    MOS capacitors with 8 nm thick oxides have been irradiated by an 8 MeV LINAC electron beam. C-V and I-V measurements have shown a positive trapped charge, higher for irradiation performed under negative gate bias, as a consequence of preferential charge recombination at the cathodic interface. No saturation of the positive trapped charge is measured up to 20 Mrad(Si). Neutral defects induced by irradiation have been studied, by performing positive and negative Fowler-Nordheim injection. The distribution of neutral defects is similar to that of trapped holes, indicating a correlation between trapped holes and neutral defects. Electrical stresses performed after irradiation have shown that the accumulation kinetics of oxide defects is similar in both unirradiated and irradiated devices.

  20. Modification of subsurface structure in TiC-(Ni-Cr) cermet composite under pulsed electron-beam irradiation of samples in plasmas of light and heavy inert gases

    NASA Astrophysics Data System (ADS)

    Ovcharenko, V. E.; Ivanov, K. V.; Baohai, Yu; Zhengkun, Li; Hua, Xu Yun; Lisheng, Zhong

    2016-11-01

    Experiments with metal ceramic alloys with various ceramic content proved that the performance degree of pulsed electron-ion-plasma irradiation as a technology of creating a surface layer multilevel structural phase condition, where particles are measured within a nano dimensional diapason, depends on ionization energy degree as well as on plasma-supporting gas atomic weight. When ionization energy falls parallel to plasma-supporting gas atomic weight growth, ceramic component particles dissolve in a metal binding melt more quickly, and an accelerated dispersion of ceramic particles to nano sized level can be observed. A multilevel structural phase condition causes friction ratio decrease, while a metal ceramic alloy surface layer wear ability increases many-folds.