Selective oxidation of propylene to acrolein by hydrothermally synthesized bismuth molybdates

DEFF Research Database (Denmark)

Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

2014-01-01

Hydrothermal synthesis has been used as a soft chemical method to prepare bismuth molybdate catalysts for the selective oxidation of propylene to acrolein. All obtained samples displayed a plate-like morphology, but their individual aspect ratios varied with the hydrothermal synthesis conditions...... of nitric acid during hydrothermal synthesis enhanced both propylene conversion and acrolein yield, possibly due to a change in morphology. Formation of β-Bi2Mo2O9 was not observed under the applied conditions. In general, the catalytic performance of all samples decreased notably after calcination at 550...

Discovery of the First Interstellar Chiral Molecule: Propylene Oxide

Science.gov (United States)

Carroll, Brandon; McGuire, Brett A.; Loomis, Ryan; Finneran, Ian A.; Jewell, Philip; Remijan, Anthony; Blake, Geoffrey

2016-06-01

Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself as a reliance on a single molecular handedness, or homochirality that is characteristic of life and perhaps most readily apparent in the large enhancement in biological activity of particular amino acid and sugar enantiomers. Yet, the ancestral origin of biological homochirality remains a mystery. The non-racemic ratios in some organics isolated from primitive meteorites hint at a primordial chiral seed but even these samples have experienced substantial processing during planetary assembly, obscuring their complete histories. To determine the underlying origin of any enantiomeric excess, it is critical to understand the molecular gas from which these molecules originated. Here, we present the first extra-solar, astronomical detection of a chiral molecule, propylene oxide (CH_3CHCH_2O), in absorption toward the Galactic Center. With the detection of propylene oxide, we at last have a target for broad-ranging searches for the possible cosmic origin of the homochirality of life.

Ac-electrical conductivity of poly(propylene) before and after X-ray irradiation

International Nuclear Information System (INIS)

Gaafar, M.

2001-01-01

Study on the ac-electrical conductivity of poly(propylene), before and after X-ray irradiation within the temperature range 300-360 K are reported. The measurements have been performed in a wide range of frequencies (from 0 to 10 5 Hz) and under the effect of different X-ray irradiation doses (from 0 to 15 Gy). Cole-Cole diagrams have been used to show the frequency dependence of the complex impedance at different temperatures. The results exhibit semicircles which are consistent with existing equivalent circuit model. Analysis of the results reveal semiconducting features based mainly on a hopping mechanism. The study shows a pronounced effect of X-ray irradiation on the electrical conductivity at zero frequency σ DC . At the early stage of irradiation, σ DC increased as a result of free radical formation. As the irradiation progressed, it decreased as a result of crosslinking, then it increased again due to irradiation induced degradation, which motivates the generation of mobile free radicals. The study shows that this polymer is one among other polymers which its electrical conductivity is modified by irradiation

Ac-electrical conductivity of poly(propylene) before and after X-ray irradiation

Science.gov (United States)

Gaafar, M.

2001-05-01

Study on the ac-electrical conductivity of poly(propylene), before and after X-ray irradiation within the temperature range 300-360 K are reported. The measurements have been performed in a wide range of frequencies (from 0 to 10 5 Hz) and under the effect of different X-ray irradiation doses (from 0 to 15 Gy). Cole-Cole diagrams have been used to show the frequency dependence of the complex impedance at different temperatures. The results exhibit semicircles which are consistent with existing equivalent circuit model. Analysis of the results reveal semiconducting features based mainly on a hopping mechanism. The study shows a pronounced effect of X-ray irradiation on the electrical conductivity at zero frequency σDC. At the early stage of irradiation, σDC increased as a result of free radical formation. As the irradiation progressed, it decreased as a result of crosslinking, then it increased again due to irradiation induced degradation, which motivates the generation of mobile free radicals. The study shows that this polymer is one among other polymers which its electrical conductivity is modified by irradiation.

Crystalline structure and propylene oxidation in complex bismuth-molybdenum oxide catalysts

International Nuclear Information System (INIS)

Manaila, R.; Ionescu, N.I.; Caldararu, M.

1980-01-01

Complex Bi-Mo oxide catalysts supported on amorphous SiO 2 were prepared by coprecipitation and tested in the reaction of selective oxidation of propylene to acrolein. They consist of a mixture of molybdate phases and excess MoO 3 . The Fe 2 (MoO 4 ) 3 phase was found to have a high concentration of lattice defects, induced by a Mo excess. These defects could be related to the catalytic conversion and to the selectivity to total oxidation by varying the calcination temperature. Calcination above 500 0 C induced also the transition of the metastable modification β-NiMoO 4 to the stable form α, accompanied by a loss of conversion. A complex Bi molybdate with scheelitic structure was found to have a high selectivity to acrolein. (author)

Polyethers for biomedical applications. Polymerization of propylene oxide by organozinc/organotin catalysts

NARCIS (Netherlands)

Bots, Jan Gert; van der Does, L.; Bantjes, Adriaan; Broersma, Jaap

1987-01-01

The polymerization of propylene oxide to obtain a high-molecular-weight polymer with an atactic structure required for the application as artificial blood vessels was investigated using combinations of organozinc and organotin compounds as catalyst. The composition of the most active catalyst,

Quantifying residues from postharvest fumigation of almonds and walnuts with propylene oxide

Science.gov (United States)

A novel analytical approach, involving solvent extraction with methyl tert-butyl ether (MTBE) followed by gas chromatography (GC), was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO,...

Selective oxidation of propylene to acrolein by silica-supported bismuth molybdate catalysts

DEFF Research Database (Denmark)

Duc, Duc Truong; Ha, Hanh Nguyen; Fehrmann, Rasmus

2011-01-01

Silica-supported bismuth molybdate catalysts have been prepared by impregnation, structurally characterized and examined as improved catalysts for the selective oxidation of propylene to acrolein. Catalysts with a wide range of loadings (from 10 to 90 wt%) of beta bismuth molybdate (β-Bi2Mo2O9) w...

Copolymerisation of Propylene Oxide and Carbon Dioxide by Dinuclear Cobalt Porphyrins

KAUST Repository

Anderson, Carly E.; Vagin, Sergei I.; Hammann, Markus; Zimmermann, Leander; Rieger, Bernhard

2013-01-01

Two dinuclear cobalt porphyrins comprising different structural tethering motifs at the porphyrin periphery were synthesised, along with a representative mononuclear cobalt porphyrin, and their catalytic activities tested towards carbon dioxide-propylene oxide copolymerisation in the presence of bis(triphenylphosphoranyl)ammonium chloride cocatalyst. The catalytic activities of the mononuclear and the bis-para-tethered dinuclear cobalt porphyrin with selective formation of poly(propylene carbonate) are largely comparable, showing no benefit of dinuclearity in contrast to the case of cobalt salen complexes and suggesting that polymer growth proceeds exclusively from one metal centre. The alternative bis-ortho-tethered porphyrin demonstrated considerably reduced activity, with dominant formation of cyclic propylene carbonate, as a result of hindered substrate approach at the metal centre. Time-resolved UV/Vis spectroscopic studies suggested a general intolerance of the cobalt(III) porphyrin catalysts towards the copolymerisation conditions in the absence of carbon dioxide pressure, leading to catalytically inactive cobalt(II) species. In the presence of carbon dioxide, the bis-ortho-tethered catalyst showed the fastest deactivation, which is related to an unfavourable steric arrangement of the linker fragment, as was also confirmed by NMR spectroscopic measurements. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copolymerisation of Propylene Oxide and Carbon Dioxide by Dinuclear Cobalt Porphyrins

KAUST Repository

Anderson, Carly E.

2013-09-18

Two dinuclear cobalt porphyrins comprising different structural tethering motifs at the porphyrin periphery were synthesised, along with a representative mononuclear cobalt porphyrin, and their catalytic activities tested towards carbon dioxide-propylene oxide copolymerisation in the presence of bis(triphenylphosphoranyl)ammonium chloride cocatalyst. The catalytic activities of the mononuclear and the bis-para-tethered dinuclear cobalt porphyrin with selective formation of poly(propylene carbonate) are largely comparable, showing no benefit of dinuclearity in contrast to the case of cobalt salen complexes and suggesting that polymer growth proceeds exclusively from one metal centre. The alternative bis-ortho-tethered porphyrin demonstrated considerably reduced activity, with dominant formation of cyclic propylene carbonate, as a result of hindered substrate approach at the metal centre. Time-resolved UV/Vis spectroscopic studies suggested a general intolerance of the cobalt(III) porphyrin catalysts towards the copolymerisation conditions in the absence of carbon dioxide pressure, leading to catalytically inactive cobalt(II) species. In the presence of carbon dioxide, the bis-ortho-tethered catalyst showed the fastest deactivation, which is related to an unfavourable steric arrangement of the linker fragment, as was also confirmed by NMR spectroscopic measurements. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlled synthesis of multi-arm star polyether-polycarbonate polyols based on propylene oxide and CO2.

Science.gov (United States)

Hilf, Jeannette; Schulze, Patricia; Seiwert, Jan; Frey, Holger

2014-01-01

Multi-arm star copolymers based on a hyperbranched poly(propylene oxide) polyether-polyol (hbPPO) as a core and poly(propylene carbonate) (PPC) arms are synthesized in two steps from propylene oxide (PO), a small amount of glycidol and CO2 . The PPC arms are prepared via carbon dioxide (CO2 )/PO copolymerization, using hbPPO as a multifunctional macroinitiator and the (R,R)-(salcy)CoOBzF5 catalyst. Star copolymers with 14 and 28 PPC arms, respectively, and controlled molecular weights in the range of 2700-8800 g mol(-1) are prepared (Mw /Mn = 1.23-1.61). Thermal analysis reveals lowered glass transition temperatures in the range of -8 to 10 °C for the PPC star polymers compared with linear PPC, which is due to the influence of the flexible polyether core. Successful conversion of the terminal hydroxyl groups with phenylisocyanate demonstrates the potential of the polycarbonate polyols for polyurethane synthesis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Carcinogenic activity of ethylene oxide and its reaction products 2-chloroethanol, 2-bromoethanol, ethylene glycol and diethylene glycol. I. Carcinogenicity of ethylene oxide in comparison with 1,2-propylene oxide after subcutaneous administration in mice (author's transl)].

Science.gov (United States)

Dunkelberg, H

1981-12-01

Ethylene oxide is an important initial product for a number of organic compounds and, in addition, is used in the medical field for sterilization. The aim of our experiments was to test ethylene oxide and, as a comparative substance, 1,2-propylene oxide in respect to their cancerogenic effectiveness in animal experiments. Ethylene oxide was administered subcutaneously in three dosages (1.0; 0.3 and 0.1 mg single dosage per mouse) once per week to groups of 100 female NMRI mice respectively. In the case of 1,2-propylene oxide, four dosages were used (2.5; 1.0; 0.3 and 0.1 mg single dosage per mouse). The vehicle was tricaprylin. Administrations were carried out over a period of 95 weeks. The mean total dosage per mouse in the case of ethylene oxide amounted to 64.4; 22.7, and 7.3 mg and, in the case of propylene oxide, to 165.4; 72.8; 21.7 and 6.8 mg. Both substances induced local tumours depending upon the dosage. There were mostly fibrosarcomas. In the case of the groups treated with ethylene oxide the frequency was between 11 and 5% and in the case of the groups treated with 1,2-propylene oxide this was between 16 and 2%. The cancerogenic effect of ethylene oxide and 1,2-propylene oxide determined in animal experiments could, therefore, be confirmed statistically. On the basis of the results presented in this paper, new aspects have arisen for the medical evaluation of ethylene oxide residues in the field of manufacturing and use and in respect to the TLV.

Systematic study on the influence of the morphology of α-MoO3 in the selective oxidation of propylene

DEFF Research Database (Denmark)

Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

2015-01-01

A variety of morphologically different α-MoO3 samples were prepared by hydrothermal synthesis and applied in the selective oxidation of propylene. Their catalytic performance was compared to α-MoO3 prepared by flame spray pyrolysis (FSP) and a classical synthesis route. Hydrothermal synthesis from...... with nitric acid at 180°C. Particularly, if nitric acid was used during synthesis, the rod-like morphology of the samples could be stabilized during calcination at 550°C and the following catalytic activity tests, which was beneficial for the catalytic performance in propylene oxidation. Characterization...... studies using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy showed that those samples, which retained their rod-like morphology during the activity tests, yielded the highest propylene conversion....

Gamma radiation effects on an amine antioxidant added in an ethylene-propylene copolymer

International Nuclear Information System (INIS)

Anelli, P.; Baccaro, S.; Casadio, C.

1998-01-01

The aim of this work was to compare the gamma radiation induced effects on samples of an ethylene-propylene copolymer antioxidant free with samples loaded with an antioxidant characterised by the presence of an -NH functional group. The employed techniques were Electron Spin Resonance spectroscopy (ESR) and High Performance Liquid Chromatography (HPLC). Stable radicals R-NO degree sign due to the interaction of free radicals produced in the irradiated polymer with the antioxidant have been observed by ESR at room temperature. The time evolution of the ESR signals following the irradiation was examined at different doses. The amount of antioxidant not involved in the oxidation reactions has been determined using HPLC

UV stabilization of wood by nano metal oxides dispersed in propylene glycol.

Science.gov (United States)

Nair, Sreeja; Nagarajappa, Giridhar B; Pandey, Krishna K

2018-06-01

Nanoparticles of some of the metal oxides are known to have high UV protective efficiency. The UV filtering efficiency of nanoparticles invariably depends on their size and stability in the dispersion. In the present work, a stable dispersion of nanoparticles of three metal oxides, zinc oxide (ZnO), cerium oxide (CeO 2 ) and titanium dioxide (TiO 2 ), was prepared in propylene glycol (PG) using ultrasonication. The method is easy and useful as no additional surfactant or dispersant is needed. The particle size and its distribution was confirmed by Scanning Electron Microscopy and Dynamic Light Scattering. The stability of dispersion was assessed by UV-visible absorption spectroscopy. The UV stability of wood surfaces of Wrightia tinctoria coated with nanodispersions of ZnO, CeO 2 and TiO 2 was evaluated under laboratory conditions in an accelerated weathering tester. Changes in the colour and FTIR spectra of exposed specimens were measured periodically. Rapid colour darkening (yellowing) was observed in uncoated and PG coated specimens. In contrast, nanodispersion coated specimens prevented photo-yellowing considerably with significant reduction in colour changes examined by CIE L*, a*, b* and ΔE*. Increase in concentration of nanoparticles in the dispersion imparted higher resistance to UV induced degradation. However, increased concentration of nanoparticles reduced the transparency of the coating. FTIR analysis indicated rapid degradation of lignin in uncoated and PG coated specimens due to UV exposure. Coating of wood surfaces with nanodispersions restricted lignin degradation. The study also demonstrates the potential of propylene glycol as a dispersant for developing stable and efficient UV protective nanodispersions for wood coating. Copyright © 2018 Elsevier B.V. All rights reserved.

Alberta propylene upgrading prospects

International Nuclear Information System (INIS)

2000-03-01

A very significant byproduct recovery and purification scheme is at present being prepared by TransCanada Midstream (TCMS). Alberta Economic Development commissioned an independent study to identify propylene supply options while proceeding with the evaluation of various propylene derivatives with regard to their fit with the Alberta context. Identification of chemical companies with derivative interests was also accomplished. By 2005, it is estimated that 280 kilo-tonnes of propylene will be available on an annual basis from byproduct sources. Those sources are oil sands upgraders, ethylene plants and refineries. The ranges of impurities and supply costs vary between the different sources. An option being considered involves pipeline and rail receipt with a major central treating and distillation facility for the production of polymer grade (PG) propylene with propane and other smaller byproducts. Special consideration was given to three chemicals in this study, namely: polypropylene (PP), acrylonitrile (ACN), and acrylic acid (AA). Above average growth rates were identified for these chemicals: demand is growing at 6 to 7 per cent a year for both PP and ACN, while demand for AA grows at 8 per cent annually. Two other possibilities were identified, propylene oxide (PO) and phenol. The study led to the conclusion that low capital and operating costs and shipping costs to the Pacific Rim represent advantages to the development of propylene derivatives in the future in Alberta. 4 refs., 87 tabs., 7 figs

Mechanism of propylene oxidation over bismuth molybdate revealed by transient response method--1. An intermediate in the complete oxidation of C/sub 3/H/sub 6/

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, M.; Futaya, R.

1979-01-01

An intermediate in the complete oxidation of C/sub 3/H/sub 6/ and its nature were deduced from transient response studies of a flow reactor system with a 1:1 bismuth-molybdenum catalyst at temperatures below ordinary operating temperatures. The formation of a stable surface intermediate with a non-allylic structure resembling that of propylene on every site of the catalyst surface occurred at 310/sup 0/C in the presence of propylene/oxygen or acrolein/oxygen; under oxidative conditions at 310/sup 0/C about eight times more intermediate formed directly from propylene than from adsorbed acrolein. The intermediate reacted with weakly adsorbed oxygen from the gas phase, but not with lattice oxygen, to decompose into CO/sub 2/; in temperature programed desorption studies (2.3/sup 0/C/min) it desorbed as CO/sub 2/ into a stream of helium above 220/sup 0/C (peak at 420/sup 0/C), apparently by reaction with oxygen diffused from the bulk to the surface.

Propylene epoxydation with hydrogen peroxide in acidic conditions

NARCIS (Netherlands)

Kertalli, E.; Rijnsoever, L.S.; Paunovic, V.; Schouten, J.C.; Neira d'Angelo, M.F.; Nijhuis, T.A.

2016-01-01

In the present work, the epoxidation of propylene with hydrogen peroxide in the presence of acids and halides is studied. The presence of acids and halides is indispensable for increasing the selectivity of the direct synthesis of hydrogen peroxide, the first step of the direct propylene oxide

Morphological Development of Melt Crystallized Poly(propylene oxide) by In Situ AFM: Formation of Banded Spherulites

NARCIS (Netherlands)

Beekmans, L.G.M.; Hempenius, Mark A.; Vancso, Gyula J.

2004-01-01

The morphology of poly(propylene oxide) (PPO) crystals grown from the melt was investigated. The spherulites of the optically pure S polymers displayed a regular pattern of concentric rings as observed by polarizing optical microscopy, while the stereocopolymer developed irregularly banded, or

Cooperative properties of single phases of complex oxide catalyst for oxidation of propylene to acrolein

International Nuclear Information System (INIS)

Orel, L.I.; Udalova, O.V.; Korchak, V.N.; Isaev, O.V.; Krylov, O.V.; Gershenzon, Yu.M.; Aptekar', E.L.

1992-01-01

Synergetic effect of increase of acrolein yield during propylene oxidation on mechanical mixture of (α + β)CoMoO 4 and MoO 3 , as well as CO and CO 2 yield on mixture of CoMoO 4 and Bi 2 O 3 ·2MoO 3 was revealed. It is shown that CoMoO 4 generates allyl radicals, desorption of these radicals to gaseous phase is not practically observed with MoO 3 , bismuth molybdates and Fe 2 O 3 · Fe 2 O 3 ·3MoO 3

Characterization of nylon 6/poly(propylene oxide) polymeric mixture by combined NMR techniques

International Nuclear Information System (INIS)

Costa, Dilma Alves; Oliveira, Clara Marize F.; Tavares, Maria Ines B.

1995-01-01

Polymeric mixtures aim to improve physical or chemical properties of materials. This mixtures can be compatible or not. The compatibility between polymers determine changes of properties. This work has presented a detailed study where nylon 6 and poly(propylene oxide) mixture was analysed by 13 C NMR in the solid state, and NMR spectra were shown and explained. The molecular mobility as well as the compatibility have been observed and discussed

Interaction of propylene with reduced surface of chromium molybdate

International Nuclear Information System (INIS)

Konovalova, N.D.; Belokopytov, Yu.V.

1978-01-01

It has been found that reduction of oxidated chromium molybdate sample by propylene at 450 deg C does not change the form of energy surface heterogeneity and also practically does not effect activation desorption energy of C 3 H 6 . It is shown that oxygen of this catalyst volume is movable and is responsible for formation of products of C 3 H 6 partial oxidation (acetic aldehyde and acrolein) in the sample reduction by propylene

Radiation treated propylene polymers

International Nuclear Information System (INIS)

Hoffman, W.A. III; Baum, G.A.

1982-01-01

A method is provided for imparting improved strength and discoloration resistance to a stabilized propylene polymer that is to be exposed to a sterilizing dose of radiation. From 200 to 400 ppm of a phenolic antioxidant containing an isocyanurate group in its molecular structure, and a thiosynergist in an amount at least 6 times the weight of the antioxidant, are incorporated into the polymer before irradiation

Quantifying Residues from Postharvest Propylene Oxide Fumigation of Almonds and Walnuts.

Science.gov (United States)

Jimenez, Leonel R; Hall, Wiley A; Rodriquez, Matthew S; Cooper, William J; Muhareb, Jeanette; Jones, Tom; Walse, Spencer S

2015-01-01

A novel analytical approach involving solvent extraction with methyl tert-butyl ether (MTBE) followed by GC was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO, propylene chlorohydrin (PCH) [1-chloropropan-2-ol (PCH-1) and 2-chloropropan-1-ol (PCH-2)], and propylene bromohydrin (PBH) [1-bromopropan-2-ol (PBH-1) and 2-bromopropan-1-ol (PBH-2)] was accomplished with a combination of electron impact ionization MS (EIMS), negative ion chemical ionization MS (NCIMS), and electron capture detection (ECD). Respective GC/EIMS LOQs for PPO, PCH-1, PCH-2, PBH-1, and PBH-2 in MTBE extracts were [ppm (μg/g nut)] 0.9, 2.1, 2.5, 30.3, and 50.0 for almonds and 0.8, 2.2, 2.02, 41.6, and 45.7 for walnuts. Relative to GC/EIMS, GC-ECD analyses resulted in no detection of PPO, similar detector responses for PCH isomers, and >100-fold more sensitive detection of PBH isomers. NCIMS did not enhance detection of PBH isomers relative to EIMS and was, respectively, approximately 20-, 5-, and 10-fold less sensitive to PPO, PCH-1, and PCH-2. MTBE extraction efficiencies were >90% for all analytes. The 10-fold concentration of MTBE extracts yielded recoveries of 85-105% for the PBH isomers and a concomitant decrease in LODs and LOQs across detector types. The recoveries of PCH isomers and PPO in the MTBE concentrate were relatively low (approximately 50 to 75%), which confound improvements in LODs and LOQs regardless of detector type.

Correlation between the size and the magnetic properties of Ag2+ clusters loaded on ceria surface and their catalytic performance in the total oxidation of propylene. EPR study

Science.gov (United States)

Hany, Sara; Skaf, Mira; Aouad, Samer; Gennequin, Cédric; Labaki, Madona; Abi-Aad, Edmond; Aboukaïs, Antoine

2018-03-01

Three different types of Ag2+ ions ("a", "b", and "c") have been identified and examined by electron paramagnetic resonance (EPR) on 10% wt Ag/CeO2 prepared by impregnation method. One of them, Ag2+(b), behaves differently than the two others, Ag2+(a) and Ag2+(c), under redox atmospheres. The fact that, in reducing conditions (vacuum, propylene, hydrogen, and carbon black), Ag2+(a) and Ag2+(c) species were more easily reduced than Ag2+(b) ones, could not explain the catalytic performance and stability of this latter species compared to the first ones in the reaction of total oxidation of propylene. The EPR technique evidenced that Ag2+(b) species form, upon propene oxidation, a cluster. This cluster is composed of two parallel electron spins (dimer) and three nuclear spins (trimer). It seems that before propylene oxidation, Ag2+(b) clusters were ferromagnetic. This ferromagnetic character of Ag2+(b) species may explain their better catalytic performance, in propylene oxidation, than those of Ag2+(a) and Ag2+(c) ones.

Effect of poly(ethylene oxide) homopolymer and two different poly(ethylene oxide-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers on morphological, optical, and mechanical properties of nanostructured unsaturated polyester.

Science.gov (United States)

Builes, Daniel H; Hernández-Ortiz, Juan P; Corcuera, Ma Angeles; Mondragon, Iñaki; Tercjak, Agnieszka

2014-01-22

Novel nanostructured unsaturated polyester resin-based thermosets, modified with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and two poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymers (BCP), were developed and analyzed. The effects of molecular weights, blocks ratio, and curing temperatures on the final morphological, optical, and mechanical properties were reported. The block influence on the BCP miscibility was studied through uncured and cured mixtures of unsaturated polyester (UP) resins with PEO and PPO homopolymers having molecular weights similar to molecular weights of the blocks of BCP. The final morphology of the nanostructured thermosetting systems, containing BCP or homopolymers, was investigated, and multiple mechanisms of nanostructuration were listed and explained. By considering the miscibility of each block before and after curing, it was determined that the formation of the nanostructured matrices followed a self-assembly mechanism or a polymerization-induced phase separation mechanism. The miscibility between PEO or PPO blocks with one of two phases of UP matrix was highlighted due to its importance in the final thermoset properties. Relationships between the final morphology and thermoset optical and mechanical properties were examined. The mechanisms and physics behind the morphologies lead toward the design of highly transparent, nanostructured, and toughened thermosetting UP systems.

Hofmeister effect of salt mixtures on thermo-responsive poly(propylene oxide)

DEFF Research Database (Denmark)

Moghaddam, Saeed Zajforoushan; Thormann, Esben

2015-01-01

of aqueous solutions of poly(propylene oxide) is affected by mixtures of ions with different location in the Hofmeister series. Our results show that the Hofmeister effects of pure salt species are not always linearly additive and that the relative effect of some ions can be reversed depending...... on the composition of the salt mixture as well as by the absolute and relative concentration of the different species. We suggest that these results can lead to a better understanding of the potential role of the Hofmeister effect in regulation of biological processes, which does always take place in salt mixtures...... rather than solutions containing just single salt species....

Theoretical consideration on phase behaviors of poly(ethylene oxide-block-propylene oxide)/LiCF3SO3 systems in lithium battery

International Nuclear Information System (INIS)

Ko, Sung Jin; Kim, Sun Joon; Kong, Sung Ho; Bae, Young Chan

2004-01-01

A new thermodynamic model is developed based on the extended perturbed hard sphere chain (PHSC) model and melting point depression theory to describe the phase behaviors of copolymer electrolyte/salt systems. The phase behaviors of poly(ethylene oxide-block-propylene oxide)/LiCF 3 SO 3 systems are investigated by thermo-optical analysis (TOA) technique. Quantitative descriptions according to the proposed model are in good agreement with experimental data. The obtained results show that monomer ratio and sequence type of copolymers play a great role in determining eutectic points of the given systems

Effect of acid on the aggregation of poly(ethylene xide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers.

Science.gov (United States)

Yang, Bin; Guo, Chen; Chen, Shu; Ma, Junhe; Wang, Jing; Liang, Xiangfeng; Zheng, Lily; Liu, Huizhou

2006-11-23

The acid effect on the aggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers EO(20)PO(70)EO(20) has been investigated by transmission electron microscopy (TEM), particle size analyzer (PSA), Fourier transformed infrared, and fluorescence spectroscopy. The critical micellization temperature for Pluronic P123 in different HCl aqueous solutions increases with the increase of acid concentration. Additionally, the hydrolysis degradation of PEO blocks is observed in strong acid concentrations at higher temperatures. When the acid concentration is low, TEM and PSA show the increase of the micelle mean diameter and the decrease of the micelle polydispersity at room temperature, which demonstrate the extension of EO corona and tendency of uniform micelle size because of the charge repulsion. When under strong acid conditions, the aggregation of micelles through the protonated water bridges was observed.

Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

Directory of Open Access Journals (Sweden)

2011-09-01

Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

77 FR 28493 - Propylene Oxide; Tolerance Actions

Science.gov (United States)

2012-05-15

.... SUMMARY: EPA is establishing the tree nut crop group tolerance and separate tolerances on pistachio and...; nut, tree, group 14; and pistachio; and in 40 CFR 180.491(a)(2) tolerances for propylene chlorohydrin at 10.0 ppm on nut, pine; nut, tree, group 14; and pistachio. Also, in accordance with current Agency...

The influence of starch oxidization and aluminate coupling agent on interfacial interaction, rheological behavior, mechanical and thermal properties of poly(propylene carbonate)/starch blends

Science.gov (United States)

Jiang, Guo; Zhang, Shui-Dong; Huang, Han-Xiong; The Key Laboratory of Polymer Processing Engineering of the Ministry of Education Team

Poly(propylene carbonate) (PPC) is a kind of new biodegradable polymer that is synthesized by copolymerization of propylene oxide and carbon dioxide. In this work, PPC end-capped with maleic anhydride (PPCMA)/thermoplastic starch (TPS), PPCMA/thermoplastic oxidized starch (TPOS) and PPCMA/AL-TPOS (TPOS modified by aluminate coupling agent) blends were prepared by melt blending to improve its thermal and mechanical properties. FTIR results showed that there existed hydrogen-bonding interaction between PPCMA and starch. SEM observation revealed that the compatibility between PPCMA and TPOS was improved by the oxidation of starch. The enhanced interfacial interactions between PPCMA and TPOS led to a better performance of PPC blends such as storage modulus (G'), loss modulus (G''), complex viscosity (η*), tensile strength and thermal properties. Furthermore, the modification of TPOS by aluminate coupling agent (AL) facilitated the dispersion of oxidized starch in PPC matrix, and resulted in increasing the tensile strength and thermal stability. National Natural Science Foundation of China, National Science Fund of Guangdong Province.

Study concerning the compatibility of the mixture of nylon-6 and poly(propylene oxide) through solid state NMR

International Nuclear Information System (INIS)

Tavares, Maria I.B.; Costa, D.A.; Menezes, Sonia M.C.

1993-01-01

NMR has been frequently used for the determination of polymers compatibility. The utilization of the simple pulse technique together with the contact time variation technique has been enabling the evaluation of the compatibility of polymeric systems. This work presents the study of the behaviour of the mixture composed by nylon-6 with poly(propylene oxide) using these techniques. Results are presented

Diffusion and solubility of oxygen in γ-ray irradiated polymer insulation materials

International Nuclear Information System (INIS)

Seguchi, Tadao; Yamamoto, Yasuaki.

1986-03-01

The effects of 60 Co γ-rays irradiation on diffusion and solubility of oxygen in polymer materials for electric cable insulation materials were investigated. The polymers were polyethylene, ethylene-propylene rubber, chlorinated polyethylene, chlorosulphonated polyethylene, and chloroprene rubber. They were pure grade and several types of formulation grade. The sheets of these polymers were irradiated up to 5 - 200 Mrad under vacuum or in oxygen under pressure of 3 - 15 atm at room temperature or at 70 deg C. By a method of gas desorption, the diffusion coefficient (D) and solubility coefficient (S) of oxygen or argon in polymer materials were determined at various temperatures of 10 - 80 deg C. The D and S decreased with increase of dose, and the decrease by irradiation with oxidation was more remarkable than that by irradiation without oxidation. However, the decreases of D and S by irradiation were reduced by the formulation of polymers. The additives in formulated polymers would reduce the reactions of crosslinking or oxidation by γ-ray irradiation. The activation energy of D was scarcely changed by irradiations with and without oxidation. (author)

Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

KAUST Repository

Wilhelm, Michael E.; Anthofer, Michael H.; Reich, Robert M.; D'Elia, Valerio; Basset, Jean-Marie; Herrmann, Wolfgang A.; Cokoja, Mirza; Kü hn, Fritz

2014-01-01

The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

KAUST Repository

Wilhelm, Michael E.

2014-02-19

The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

Propylene from renewable resources: catalytic conversion of glycerol into propylene.

Science.gov (United States)

Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

2014-03-01

Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetic study of the hydration of propylene oxide in the presence of heterogeneous catalyst

Directory of Open Access Journals (Sweden)

Akyalcin Sema

2017-01-01

Full Text Available The kinetics of the hydration of propylene oxide was studied using a pressurized batch reactor for both uncatalyzed and heterogeneously catalyzed reactions. Lewatit MonoPlus M500/HCO3 - was used as heterogeneous catalyst, which showed better performance than Dowex Marathon A/HCO3 -. The effects of the parameters, namely internal and external diffusion resistances, temperature, catalyst loading and mole ratios of reactants, on the reaction rate were studied. The uncatalyzed and heterogeneously catalyzed reactions were proven to follow a series-parallel irreversible homogeneous mechanism. The temperature dependencies of the rate constants appearing in the rate expressions were determined.

Hofmeister effect on thermo-responsive poly(propylene oxide): Role of polymer molecular weight and concentration

DEFF Research Database (Denmark)

Moghaddam, Saeed Zajforoushan; Thormann, Esben

2016-01-01

) salts on aqueous solutions of poly(propylene oxide) (PPO) is studied. Four different molecular weights of PPO were investigated, to determine how the variation in the polymer coil size affects the Hofmeister effect. The investigation was further conducted for different PPO concentrations, in order...... with the transition. It was observed that increasing the molecular weight weakens the effect of the both salts, which is interpreted in terms of a scaling law between the molecular weight and the accessible surface area of the polymers. Increasing the PPO concentration further diminished the NaCl effect...

Study of the oxidation and of the mechanical behavior of irradiated elastomers: consequences of the electronic irradiation on the electrical cables during the occurring of a pressurized water reactor accident

International Nuclear Information System (INIS)

Corbin, D.

2001-01-01

This thesis contributes to a better understanding and predictions of the consequences of electronic irradiation on the electrical cables when an accident of a pressurized water reactor occurs. We studied the radio-oxidation and the mechanical behaviour of two irradiated elastomers, EPDM (ethylene-propylene-hexadiene 1,4 terpolymer) and hypalon (chloro-sulfonated polyethylene), used respectively as insulating and sheath material of the cable. In the first part, the conditions of exposure to radiation during an accident are presented. They induce a very heterogeneous dose profile in the cable because of the low range of the involved electrons. This situation contrasts with normal operating conditions of the power plant and corresponding qualification tests. In the latter case, the profile is uniform since it is deposited by γ - rays with large ranges. The second part focuses on degradation under presence of oxygen, with typical dose and dose rate conditions for an accident. Thin films of the two elastomers (basic and formulated polymers) are irradiated by electrons and the oxidation products, and their concentrations are determined chemically. The influence, on the kinetics of radio-oxidation, of three parameters typical for the irradiation, the oxygen pressure, the dose rate and the dose is presented there. The effect of antioxidants is studied in the case of EPDM. The third part describes the results concerning the experimental simulation of the dose profile during the accident on thick plates of two formulated elastomers. The evolution of the breaking mechanical properties, as a function of dose and the thickness of the plates, is presented and analysed in correlation with the oxidation profiles. (author)

A 1,2-propylene oxide sensor utilizing cataluminescence on CeO2 nanoparticles.

Science.gov (United States)

Liu, Hongmei; Zhang, Yantu; Zhen, Yanzhong; Ma, Yuan; Zuo, Weiwei

2014-12-01

A simple and sensitive gas sensor was proposed for the determination of 1,2-propylene oxide (PO) based on its cataluminescence (CTL) by oxidation in the air on the surface of CeO2 nanoparticles. The luminescence characteristics and optimal conditions were investigated in detail. Under optimized conditions, the linear range of the CTL intensity versus the concentration of PO was 10-150 ppm, with a correlation coefficient (r) of 0.9974 and a limit of detection (S/N = 3) of 0.9 ppm. The relative standard deviation for 40 ppm PO was 1.2% (n = 7). There was no or only weak response to common foreign substances including acetone, formaldehyde, ethyl acetate, acetic acid, chloroform, propanol, carbon tetrachloride, ether and methanol. There was no significant change in the catalytic activity of the sensor for 100 h. The proposed method was simple and sensitive, with a potential of detecting PO in the environment and industry. Copyright © 2014 John Wiley & Sons, Ltd.

Effect of hydrogen and propylene on the hydrogen peroxide decomposition over Pt, PtO and Au catalysts

NARCIS (Netherlands)

Kertalli, E.; Schouten, J.C.; Nijhuis, T.A.

2017-01-01

The decomposition of hydrogen peroxide (H2O2) on Pt, PtO and Au catalysts has been investigated in the presence of nitrogen, propylene and hydrogen. H2O2 formation on the catalyst is known to be a key intermediate step for the direct synthesis of propylene oxide (PO) from hydrogen, propylene and

Dynamics of the NbCl5-catalyzed cycloaddition of propylene oxide and CO2: Assessing the dual role of the nucleophilic co-catalysts

KAUST Repository

D'Elia, Valerio

2014-07-23

A mechanistic study on the synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO) catalyzed by NbCl5 and organic nucleophiles such as 4-dimethylaminopyridine (DMAP) or tetra-n-butylammonium bromide (NBu4Br) is reported. A combination of in situ spectroscopic techniques and kinetic studies has been used to provide detailed insight into the reaction mechanism, the formation of intermediates, and interactions between the reaction partners. The results of DFT calculations support the experimental observations and allow us to propose a mechanism for this reaction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reinforced poly(propylene oxide)- a very soft and extensible dielectric electroactive polymer

DEFF Research Database (Denmark)

Goswami, Kaustav; Galantini, F.; Mazurek, Piotr Stanislaw

2013-01-01

Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of ,!-diallyl PPO with a tetra-functional thiol. The elastomer...... was reinforced with hexamethylenedisilazane treated fumed silica to improve the mechanical properties of PPO. The mechanical properties of PPO and composites thereof were investigated by shear rheology and stress–strain measurements. It was found that incorporation of silica particles improved the stability...... of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 103 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910...

Radiation stabilization effects in an ethylene-propylene copolymer and in epoxy resin particulate composites

International Nuclear Information System (INIS)

Baccaro, S.; Bianchilli, B.; Casadio, C.; Rinaldi, G.

1999-01-01

The aim of this work was to investigate the post-g-irradiation behavior of an ethylene-propylene copolymer loaded with an antioxidant containing the -NH functional group. The oxidative degradation of the polymer was studied using Infrared Absorption Spectroscopy. The shape of the oxidation profiles, and the dependence on thickness and on dose rate were in good agreement with the Gillen and Clough model. The interaction of polymeric free radicals with the antioxidant led to the formation of R-NO . stable radicals. These species are easily detectable using Electron Spin Resonance Spectroscopy. We used this technique to study the influence of the total absorbed dose, of dose rate and of oxygen and the time evolution of the oxidation products. High Performance Liquid Chromatography allowed us to determine the amount of antioxidant not involved in the oxidation reaction as a function of the total absorbed dose. The stabilization toward gamma radiation effects, of different types of curing agents for epoxide resins, and of fly ash as filler, were also investigated through monitoring the mechanical properties of such composite materials. (author)

Mechanism of Propylene Oxide Polymerization Promoted by N-Heterocyclic Olefins

KAUST Repository

Al-Ghamdi, Miasser

2017-01-11

We report a mechanistic DFT investigation of the organopolymerization of propylene oxide (PO) promoted by N-heterocyclic olefins (NHOs) in combination with benzylic alcohol (BnOH). Calculations support the experimentally based hypothesis of two competing pathways, namely, the anionic and zwitterionic pathways. The former is based on an acid–base cooperativity between BnOH and the NHO, promoting ring opening of PO by BnO–. The latter occurs through the formation of a zwitterionic adduct by nucleophilic attack of the exocyclic carbon atom of the NHO on the PO, with the concerted ring opening of PO. The two initiating species cannot interconvert, and chain elongation can proceed from both initiation adducts. Potential energy surfaces were computed for a set of NHOs to clarify the effects of the steric and electronic properties of the NHO on the system reactivity. The results achieved represent useful insight toward the synthesis of PPO with better properties with respect to the polymer obtained with the experimental tested systems because the computationally proposed NHO system is the only one that favors the mechanism leading to higher molecular weight.

The Relationship Between Structural and Catalytic Activity of α and γ-Bismuth-Molybdate Catalysts for Partial Oxidation of Propylene to Acrolein

Science.gov (United States)

Fansuri, H.; Pham, G. H.; Wibawanta, S.; Zhang, D. K.; French, David

Bismuth-molybdate catalysts are known to be effective for catalytic partial oxidation of propylene to acrolein. Their properties and the kinetics and reaction mechanisms for acrolein production have been extensively studied, especially in their basic forms, such as α, β, and γ-bismuth-molybdate. Although the reaction mechanisms have been reported widely in the literature, a general agreement has not been reached, especially from a catalyst-structure point of view. The present contribution reports an effort to understand the structural changes of α and γ-bismuth-molybdate catalysts at varying temperatures as examined using high temperature XRD and to relate the catalyst performance (activity and selectivity) for propylene partial oxidation to acrolein. The XRD analysis was performed at temperature between 250 and 450°C in ambient atmosphere and the Rietveld refinement method was used to extract unit cell parameters. The results showed a distinct similarity between the shapes of the thermal expansion of the catalysts and their activity and selectivity curves, indicating a significant role that the catalyst interatomic structure plays in the overall reaction mechanism.

Study of ternary-component bismuth molybdate catalysts by 18O2 tracer in the oxidation of propylene to acrolein

International Nuclear Information System (INIS)

Ueda, W.; Moro-oka, Y.; Ikawa, T.

1981-01-01

Participation of lattice oxide ions of ternary-component bismuth molybdate catalysts M-Bi-Mo-O (M = Ni, Co, Mg, Mn, Ca, Sr, Ba, and Pb) was investigated using the 18 O 2 tracer in the selective oxidation of propylene to acrolein. The participation of the lattice oxide ions in the oxidation is prominent on every catalyst but the extent of the participation varies significantly depending on the structure of the catalyst. Only lattice oxide ions in the bismuth molybdate phase are incorporated into the oxidized products on the catalysts (M = Ni, Co, Mg, and Mn) where M have smaller ionic radius than Bi 3+ ; catalyst particles are composed of a shell of bismuth molybdates and a core of MMoO 4 . On the other hand, whole oxide ions in the active particles are involved in the oxidation on catalysts having a scheelite-type structure (M = Ca, Sr, Ba, and Pb) where M has a comparable ionic radius to Bi 3+

Study of inhibition on lipid oxidation of irradiated pork

International Nuclear Information System (INIS)

Ha Yiming

2006-03-01

It was studied that the effect factors of irradiation dose, preservation temperature, oxygen content and antioxidant on lipid oxidation of irradiated pork. A mechanism was explained on lipid oxidation of irradiated pork. The results showed that irradiation might aggravate lipid oxidation of pork and that decreased preservation temperature and oxygen content of the packaging, added antioxidant also could effectively inhibit lipid oxidation of irradiated pork. (authors)

Nucleophile-directed selectivity towards linear carbonates in the niobium pentaethoxide-catalysed cycloaddition of CO2 and propylene oxide

KAUST Repository

Dutta, Barnali

2014-01-01

Homoleptic Nb-complexes combined with selected organic nucleophiles generate very active catalytic systems for the cycloaddition of propylene oxide and CO2 under ambient conditions. An unprecedented reaction pathway towards an acyclic organic carbonate is observed when extending the study to [Nb(OEt)5] in combination with 4-dimethylamino-pyridine (DMAP) or tetra-n-butylammonium bromide (TBAB). Mechanistic insights of the reaction are provided based on experimental and spectroscopic evidences. This journal is © the Partner Organisations 2014.

Absolute rate constants for the reaction of O(3P) atoms with ethylene, propylene, and propylene-d6 over the temperature range 258--861 K

International Nuclear Information System (INIS)

Perry, R.A.

1984-01-01

Absolute rate constants for the reaction of O( 3 P) with ethylene, propylene, and propylene-d6 were determined over the temperature range 258--861 K using a laser photolysis-chemiluminescence technique. The following empirical expressions are the best fits to the data: k/sub ethylene/ = 2.12 x 10 -13 T -63 e -1370 /sup ///sup R//sup T/, k/sub propylene/ = 3.40 x 10 -19 T/sup 2.56/e/sup 1130/RT/, and k/sub propylene-d/6 = 3.40 x 10 -19 T/sup 2.53/ e/sup 1210/R/T cm 3 molecule -1 s -1 . A simple transition state theory model is shown to provide a reasonable explanation for non-Arrhenius temperature behavior

Electrochromic nickel oxide films and their compatibility with potassium hydroxide and lithium perchlorate in propylene carbonate: Optical, electrochemical and stress-related properties

International Nuclear Information System (INIS)

Wen, Rui-Tao; Niklasson, Gunnar A.; Granqvist, Claes G.

2014-01-01

Porous nickel oxide films were deposited onto unheated indium tin oxide coated glass substrates by reactive dc magnetron sputtering. These films had a cubic NiO structure. Electrochromic properties were evaluated in 1 M potassium hydroxide (KOH) and in 1 M lithium perchlorate in propylene carbonate (Li–PC). Large optical modulation was obtained for ∼ 500-nm-thick films both in KOH and in Li–PC (∼ 70% and ∼ 50% at 550 nm, respectively). In KOH, tensile and compressive stresses, due to the expansion and contraction of the lattice, were found for films in their bleached and colored state, respectively. In Li–PC, compressive stress was seen both in colored and bleached films. Durability tests with voltage sweeps between − 0.5 and 0.65 V vs Ag/AgCl in KOH showed good durability for 10,000 cycles, whereas voltage sweeps between 2.0 and 4.7 V vs Li/Li + in Li–PC yielded significant degradation after 1000 cycles. - Highlights: • Ni oxide films were studied in KOH and in LiClO 4 + propylene carbonate (Li–PC). • Good electrochromism was found in both electrolytes. • In KOH, tensile/compressive stresses were seen in bleached/colored films. • In Li–PC, compressive stress was seen both in colored and bleached films

Life's First Handshake - Discovery of the Interstellar Chiral Molecule Propylene Oxide

Science.gov (United States)

McGuire, Brett A.; Carroll, P. Brandon; Loomis, Ryan A.; Finneran, Ian A.; Jewell, Philip R.; Remijan, Anthony J.; Blake, Geoffrey A.

2016-06-01

Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere, and is perhaps most readily apparent in the large enhancement in biological activity of particular amino acid and sugar enantiomers. Yet, the ancestral origin of biological homochirality remains a mystery. The non-racemic ratios in some organics isolated from primitive meteorites hint at a primordial chiral seed, but even these samples have experienced substantial processing during planetary assembly, obscuring their complete histories. To determine the underlying origin of any enantiomeric excess, it is critical to understand the molecular gas from which these molecules originated. Here, we present the first extra-solar, astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic Center. We discuss the implications of the detection on observational searches to determine a primordial chiral excess, as well as the state of laboratory efforts in these areas.

Reinforced poly(propylene oxide): a very soft and extensible dielectric electroactive polymer

International Nuclear Information System (INIS)

Goswami, K; Mazurek, P; Daugaard, A E; Skov, A L; Galantini, F; Gallone, G

2013-01-01

Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of α,ω-diallyl PPO with a tetra-functional thiol. The elastomer was reinforced with hexamethylenedisilazane treated fumed silica to improve the mechanical properties of PPO. The mechanical properties of PPO and composites thereof were investigated by shear rheology and stress–strain measurements. It was found that incorporation of silica particles improved the stability of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 10 3 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910. The electromechanical actuation performance of both PPO and its composites showed properties as good as VHB4910 and a lower viscous loss. (paper)

Study of the mechanisms controlling the oxide growth under irradiation: characterization of irradiated zircaloy-4 and Zr-1 Nb-O oxide scales

International Nuclear Information System (INIS)

Bossis, Ph.; Thomazet, J.; Lefebvre, F.

2002-01-01

In PWRs, the Zr-1Nb-O alloy shows a marked enhancement in corrosion resistance in comparison with Zircaloy-4. The aim of this work is to analyze the reasons for these different behaviors and to determine the respective nature of the oxide growth controlling mechanisms under irradiation. Samples taken from Zircaloy-4 irradiated 1, 2, and 4 cycles and Zr-1Nb-O irradiated 1 and 3 cycles have been systematically characterized by optical microscopy, SEM coupled with image analysis, hydride distribution, and XRD. Specific TEM characterizations have been performed on the Zr-1Nb-O samples. A XPS analysis of a nonirradiated sample is also reported. It has been shown that under irradiation the slow oxidation kinetics of the Zr-1Nb-O alloy is associated with very regular metal-oxide interface and oxide layer. On the contrary, the accelerated oxidation kinetics of Zircaloy-4 is associated with highly perturbed metal-oxide interface and oxide layer. On both irradiated alloys, cracks are observed to initiate preferentially above the delayed parts of the oxidation front. Hydrogen intake during water oxidation in PWR environment is found to be much lower on the Zr-1Nb-O alloy than on Zircaloy-4. More β-ZrO 2 is found on the oxide layer formed on Zircaloy-4 than on Zr-1NbO after oxidation in PWR. Classical irradiation-induced microstructural evolution is observed in the Zr-1Nb-O metallic alloy after 3 cycles, i.e., a fine β-Nb precipitation. β-Nb precipitates are observed to undergo a delayed oxidation associated with a crystalline to amorphous transformation. After water oxidation in autoclave, a pronounced Nb segregation is detected on the oxide surface of a Zr-1Nb-O sample. These results suggest that the oxidation kinetics of Zircaloy-4 is controlled essentially by oxygen diffusion through the inner barrier layer, which is significantly accelerated under irradiation. The oxidation kinetics of Zr-1Nb-O is controlled by both oxygen diffusion through the inner barrier and by

Electron trapping during irradiation in reoxidized nitrided oxide

International Nuclear Information System (INIS)

Mallik, A.; Vasi, J.; Chandorkar, A.N.

1993-01-01

Isochronal detrapping experiments have been performed following irradiation under different gate biases in reoxidized nitrided oxide (RNO) MOS capacitors. These show electron trapping by the nitridation-induced electron traps at low oxide fields during irradiation. A difference in the detrapping behavior of trapped holes and electrons is observed, with trapped holes being detrapped at relatively lower temperatures compared to trapped electrons. Electron trapping shows a strong dependence on tile magnitude of the applied gate bias during irradiation but is independent of its polarity. Conventional oxide devices, as expected, do not show any electron trapping during irradiation by the native electron traps. Finally, a comparison of the isochronal detrapping behavior following irradiation and following avalanche injection of electrons has been made to estimate the extent of electron trapping. The results show that electron trapping by the nitridation-induced electron traps does not play the dominant role in improving radiation performance of RNO, though its contribution cannot be completely neglected for low oxide field irradiations

Electrochromic nickel oxide films and their compatibility with potassium hydroxide and lithium perchlorate in propylene carbonate: Optical, electrochemical and stress-related properties

Energy Technology Data Exchange (ETDEWEB)

Wen, Rui-Tao, E-mail: Ruitao.Wen@angstrom.uu.se; Niklasson, Gunnar A.; Granqvist, Claes G.

2014-08-28

Porous nickel oxide films were deposited onto unheated indium tin oxide coated glass substrates by reactive dc magnetron sputtering. These films had a cubic NiO structure. Electrochromic properties were evaluated in 1 M potassium hydroxide (KOH) and in 1 M lithium perchlorate in propylene carbonate (Li–PC). Large optical modulation was obtained for ∼ 500-nm-thick films both in KOH and in Li–PC (∼ 70% and ∼ 50% at 550 nm, respectively). In KOH, tensile and compressive stresses, due to the expansion and contraction of the lattice, were found for films in their bleached and colored state, respectively. In Li–PC, compressive stress was seen both in colored and bleached films. Durability tests with voltage sweeps between − 0.5 and 0.65 V vs Ag/AgCl in KOH showed good durability for 10,000 cycles, whereas voltage sweeps between 2.0 and 4.7 V vs Li/Li{sup +} in Li–PC yielded significant degradation after 1000 cycles. - Highlights: • Ni oxide films were studied in KOH and in LiClO{sub 4} + propylene carbonate (Li–PC). • Good electrochromism was found in both electrolytes. • In KOH, tensile/compressive stresses were seen in bleached/colored films. • In Li–PC, compressive stress was seen both in colored and bleached films.

Lipid analyses of fumigated vs irradiated raw and roasted almonds

International Nuclear Information System (INIS)

Uthman, R.S.; Toma, R.B.; Garcia, R.; Medora, N.P.; Cunningham, S.

1998-01-01

The purpose of this study was to compare the effects of propylene oxide (PO) and irradiation treatments on the lipid analyses of raw and roasted almonds. Eight kilograms each of raw and roasted almonds were divided into four batches (2 kg each). Three of the batches were subjected to PO treatment or irradiation treatment with a dose of 6, 10·5 kGy. The untreated batch served as control samples, they were taken from all the batches at three consecutive times during storage (day 0, 8 weeks and 16 weeks) and analysed for iodine number, peroxide value and 2-thiobarbituric acid number. Overall, irradiated almonds incurred a higher variation in lipid stability than PO tested almonds while roasted almonds incurred a higher variation than raw almonds

Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

Energy Technology Data Exchange (ETDEWEB)

Ramalho, Joao Batista V.S. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Lechuga, Fernanda C.; Lucas, Elizabete F., E-mail: elucas@ima.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

2010-07-01

Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface. (author)

Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

International Nuclear Information System (INIS)

Ramalho, Joao Batista V.S.; Lechuga, Fernanda C.; Lucas, Elizabete F.

2010-01-01

Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface. (author)

Synergy effects in mixed Bi2O3, MoO3 and V2O5 catalysts for selective oxidation of propylene

DEFF Research Database (Denmark)

Nguyen, Tien The; Le, Thang Minh; Truong, Duc Duc

2012-01-01

% Bi2Mo3O12 and 78.57 mol% BiVO4), corresponding to the compound Bi1-x/3V1-xMoxO4 with x = 0.45 (Bi0.85V0.55Mo0.45O4), exhibited the highest activity for the selective oxidation of propylene to acrolein. The mixed sample prepared chemically by a sol–gel method possessed higher activity than...

Reduction of Graphene Oxide to Graphene by Using Gamma Irradiation

International Nuclear Information System (INIS)

Shamellia Sharin; Irman Abdul Rahman; Ainee Fatimah Ahmad

2015-01-01

This research aims to gauge the ability of gamma radiation to induce the reduction of graphene oxide to graphene. Graphene oxide powders were dispersed into a mixture of alcohol and deionized water, and the mixture was then irradiated with a "6"0Co source using a GammaCell 220 Excel irradiator at absorbed doses of 0, 5, 15, 20 and 35 kGy. According to characterization using Fourier Transformed Infrared Spectroscopy (FTIR), it can be seen that almost every oxygen-containing functional group has been removed after irradiation of the graphene oxide mixture. Reduction of graphene oxide was also proven from the characterization using UV-Vis Spectroscopy, in which the wavelength of graphene oxide at 237 nm was red-shifted to 277 nm after being irradiated and the peak at 292 nm, (indicating the carboxyl group) disappears in the UV-Vis spectrum of reduced graphene oxide. Morphology of graphene oxide also changed from a smooth and flat surface to crumpled. The ratio of carbon/ oxygen in the graphene oxide was lower than the carbon/ oxygen of reduced graphene oxide. At the end of the experiment, it can be deduced that graphene oxide underwent reduction, characterized before and after irradiation using Emission Scanned Electron Microscopy and Energy Dispersive X-ray, Fourier Transformed Infrared Spectroscopy and UV-Vis Spectroscopy. Therefore, we postulate that the irradiation technique that induces reduction, can be used to obtain reduced graphene oxide from graphene oxide. (author)

Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

Directory of Open Access Journals (Sweden)

João Batista V. S. Ramalho

2010-01-01

Full Text Available Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent. No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface.

HT oxidation activity of soil irradiated with gamma radiation

International Nuclear Information System (INIS)

Momoshima, Noriyuki; Tjahaja, P.I.; Takashima, Yoshimasa

1992-01-01

The HT oxidation activity was examined for soils irradiated with 60 Co γ-rays at various doses. The HT oxidation rate decreased with increase of initial H 2 concentration, indicating a similar oxidation mechanism between HT and H 2 . Irradiated soils showed decrease of oxidation activity with dose suggests that HT and H 2 oxidation activities were affected by sterilization with γ-rays. The decline of the oxidation activity with dose was analyzed by a composite of two components with different radiosensitivity and they were considered to be activities of soil microorganisms and abiotic soil enzymes. The oxidation activity due to soil microorganisms would be important at low dose range and more radioresistant abiotic soil enzymes would be responsible for the oxidation activity observed at more than several kGy. In non-irradiated soil about half of the oxidation activity was considered resulting from abiotic soil enzymes. (author)

Volatile profile, lipid oxidation and protein oxidation of irradiated ready-to-eat cured turkey meat products

International Nuclear Information System (INIS)

Feng, Xi; Ahn, Dong Uk

2016-01-01

Irradiation had little effects on the thiobarbituric acid reactive substances (TBARS) values in ready-to-eat (RTE) turkey meat products, while it increased protein oxidation at 4.5 kGy. The volatile profile analyses indicated that the amount of sulfur compounds increased linearly as doses increased in RTE turkey meat products. By correlation analysis, a positive correlation was found between benzene/ benzene derivatives and alcohols with lipid oxidation, while aldehydes, ketones and alkane, alkenes and alkynes were positively correlated with protein oxidation. Principle component analysis showed that irradiated meat samples can be discriminated by two categories of volatile compounds: Strecker degradation products and radiolytic degradation products. The cluster analysis of volatile data demonstrated that low-dose irradiation had minor effects on the volatile profile of turkey sausages (<1.5 kGy). However, as the doses increased, the differences between the irradiated and non-irradiated cured turkey products became significant. - Highlights: • Irradiation had little effects on lipid oxidation of ready-to-eat cured turkey. • 4.5 kGy irradiation increased protein oxidation. • Irradiated samples were isolated due to Strecker/radiolytic degradation products. • 1.5 kGy irradiation had limited effects on the volatile profile of turkey sausages. • Dimethyl disulfide can be used as a potential marker for irradiated meat products.

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salenCo(III complex tethering four quaternary ammonium salts

Directory of Open Access Journals (Sweden)

Jong Yeob Jeon

2014-08-01

Full Text Available The (salenCo(III complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalates were afforded without any formation of ether linkages. In the PO/CO2/PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate-co-phthalates because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol-1 and the number of chain-growing sites per 1 [anions in 1 (5 + water (present as impurity + ethanol (deliberately fed], and the molecular weight distributions were narrow (Mw/Mn, 1.05–1.5. Because of the extremely high activity of 1, high-molecular-weight polymers were generated (Mn up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO2/PA terpolymerization, respectively. The terpolymers bearing a substantial number of PA units (fPA, 0.23 showed a higher glass-transition temperature (48 °C than the CO2/PO alternating copolymer (40 °C.

Phase behavior in blends of ethylene oxide-propylene oxide copolymer and poly(ether sulfone) studied by modulated-temperature DSC and NMR relaxometry.

Science.gov (United States)

Van Lokeren, Luk; Gotzen, Nicolaas-Alexander; Pieters, Ronny; Van Assche, Guy; Biesemans, Monique; Willem, Rudolph; Van Mele, Bruno

2009-01-01

The state diagram of a blend consisting of a copolymer containing ethylene oxide and propylene oxide, P(EO-ran-PO), and poly(ether sulfone), PES, is constructed by using modulated-temperature differential scanning calorimetry (MTDSC), T(2) NMR relaxometry, and light scattering. The apparent heat capacity signal in MTDSC is used for the characterization of polymer miscibility and morphology development. T(2) NMR relaxometry is used to detect the onset of phase separation, which is in good agreement with the onset of phase separation in the apparent heat capacity from MTDSC and the cloud-point temperature as determined from light scattering. The coexistence curve can be constructed from T(2) values at various temperatures by using a few blends with well-chosen compositions. These T(2) values also allow the detection of the boundary between the demixing zones with and without interference of partial vitrification and are in good agreement with stepwise quasi-isothermal MTDSC heat capacity measurements. Important interphases are detected in the heterogeneous P(EO-ran-PO)/PES blends.

Propylene Glycol Poisoning From Excess Whiskey Ingestion

Directory of Open Access Journals (Sweden)

Courtney A. Cunningham MD

2015-09-01

Full Text Available In this report, we describe a case of high anion gap metabolic acidosis with a significant osmolal gap attributed to the ingestion of liquor containing propylene glycol. Recently, several reports have characterized severe lactic acidosis occurring in the setting of iatrogenic unintentional overdosing of medications that use propylene glycol as a diluent, including lorazepam and diazepam. To date, no studies have explored potential effects of excess propylene glycol in the setting of alcohol intoxication. Our patient endorsed drinking large volumes of cinnamon flavored whiskey, which was likely Fireball Cinnamon Whisky. To our knowledge, this is the first case of propylene glycol toxicity from an intentional ingestion of liquor containing propylene glycol.

Preparation and characterization of starch grafted with toluene poly (propylene oxide diisocyanate

Directory of Open Access Journals (Sweden)

D.C. Dragunski

2001-01-01

Full Text Available Amylopectin-rich starch samples (Amidex 4001 Corn Products Brasil Ingredientes Industriais Ltda. were grafted with polyethers with the purpose of obtaining new materials for application as solid polymeric electrolytes. Grafting reaction was performed by the addition of starch dissolved in DMSO to toluene poly(propylene oxide diisocyanate (Resibras dissolved in the same solvent. This reaction produced a film with good mechanical properties. The film samples were characterized by 13C-NMR, FTIR, DSC, X-Ray and SEM. The FTIR spectrum shows a sharp NH band and a very small urethane band. The 13C-NMR spectrum revealed a peak at 20 ppm, that can be attributed to the CH3 of the polyether chain, and two small peaks at 117 and 140 ppm, attributed to the aromatic ring. The X-ray diffractograms also indicated that after the grafting reaction, the samples of amylopectin-rich starch are more amorphous. Moreover, the glass transition temperature (Tg dropped from 50 °C to -11 °C. These results indicate formation of grafted products and the low Tg of the samples suggests that polyether-grafted starch is a good candidate to obtain solid polymeric electrolytes.

Oxidative stability examination of irradiated swine for samples

International Nuclear Information System (INIS)

Formanek, Z.

1995-01-01

DSC (Differential Scanning Calorimetry), OBM (Oxygen Bomb Method) methods and POV (Peroxide Value) determination was applied to determine the oxidative stability of lard samples irradiated by a Co 60 gamma source at the dose of 0; 0.75; 2.5kGy. Both of the methods seem to be suitable to determine oxidative stability of fats, because in every case lowering oxidative stability was received with increasing irradiation dose. (R.P.). 8 refs., 7 figs., 1 tab

Time series analysis of blood oxidative stress value in irradiated rats

International Nuclear Information System (INIS)

Kaneko, Takashi; Goto, Jun; Nomiya, Takuma; Nemoto, Kenji

2011-01-01

Indirect effect of ionizing-radiation causes free radicals and reactive oxgen species (ROS). These ROS interact with DNA or other organella, and cause oxidative damage to nucleic acids, membrane lipoprotein, mitchondria and others. The purpose of this study is to evaluate oxidative damage by irradiation using d-ROMs test. Electron beam was irradiated to the thigh of Wistar strain female rats, and reactive oxygen metabolites in the blood from these rats were measured and analysed. From the results, 2 Gy group shows significantly higher oxidative stress level than those of 0 Gy group especially in day 3 after irradiation. This oxidative stress definitely seemed to be caused by exposure to ionizing-radiation. In contrast, the group of 30 Gy-irradiation showed no significant increase of oxidative stress level. It was thought that oxidative stress caused by radiation was neutralized by expression of stress-induced antioxidant enzymes. These data resulted that d-ROMs test is useful for measuring oxidative stress levels of irradiated mammalian animals. (author)

Enhanced low-temperature oxidation of zirconium alloys under irradiation

International Nuclear Information System (INIS)

Cox, B.; Fidleris, V.

1989-01-01

The linear growth of relatively thick (>300 nm) interference-colored oxide films on zirconium alloy specimens exposed in the Advanced Test Reactor (ATR) coolant at ≤55 o C was unexpected. Initial ideas were that this was a photoconduction effect. Experiments to study photoconduction in thin anodic zirconium oxide (ZrO 2 ) films in the laboratory were initiated to provide background data. It was found that, in the laboratory, provided a high electric field was maintained across the oxide during ultraviolet (UV) irradiation, enhanced growth of oxide occurred in the irradiated area. Similarly enhanced growth could be obtained on thin thermally formed oxide films that were immersed in an electrolyte with a high electric field superimposed. This enhanced growth was found to be caused by the development of porosity in the barrier oxide layer by an enhanced local dissolution and reprecipitation process during UV irradiation. Similar porosity was observed in the oxide films on the ATR specimens. Since it is not thought that a high electric field could have been present in this instance, localized dissolution of fast-neutron primary recoil tracks may be the operative mechanism. In all instances, the specimens attempt to maintain the normal barrier-layer oxide thickness, which causes the additional oxide growth. Similar mechanisms may have operated during the formation of thick loosely adherent, porous oxides in homogeneous reactor solutions under irradiation, and may be the cause of enhanced oxidation of zirconium alloys in high-temperature water-cooled reactors in some water chemistries. (author)

Development of examination technique for oxide layer thickness measurement of irradiated fuel rods

International Nuclear Information System (INIS)

Koo, D. S.; Park, S. W.; Kim, J. H.; Seo, H. S.; Min, D. K.; Kim, E. K.; Chun, Y. B.; Bang, K. S.

1999-06-01

Technique for oxide layer thickness measurement of irradiated fuel rods was developed to measure oxide layer thickness and study characteristic of fuel rods. Oxide layer thickness of irradiated fuels were measured, analyzed. Outer oxide layer thickness of 3 cycle-irradiated fuel rods were 20 - 30 μm, inner oxide layer thickness 0 - 10 μm and inner oxide layer thickness on cracked cladding about 30 μm. Oxide layer thickness of 4 cycle-irradiated fuel rods were about 2 times as thick as those of 1 cycle-irradiated fuel rods. Oxide layer on lower region of irradiated fuel rods was thin and oxide layer from lower region to upper region indicated gradual increase in thickness. Oxide layer thickness from 2500 to 3000 mm showed maximum and oxide layer thickness from 3000 to top region of irradiated fuel rods showed decreasing trend. Inner oxide layer thicknesses of 4 cycle-irradiated fuel rod were about 8 μm at 750 - 3500 mm from the bottom end of fuel rod. Outer oxide layer thickness were about 8 μm at 750 - 1000 mm from the bottom end of fuel rod. These indicated gradual increase up to upper region from the bottom end of fuel rod. These indicated gradual increase up to upper region from the bottom end of fuel. Oxide layer thickness technique will apply safety evaluation and study of reactor fuels. (author). 6 refs., 14 figs

Relationship between measurements of blood oxidative metabolites and skin reaction in irradiated rats

International Nuclear Information System (INIS)

Kaneko, Takashi; Goto, Jun; Nomiya, Takuma; Nemoto, Kenji

2011-01-01

Recently, oxidative metabolites have been able to be measured by simple small device. It has been reported that the value of oxidative metabolites increases under several conditions such as hypertension, smoking, diabetes mellitus, etc. Radiation used in radiotherapy also causes free radicals and oxidative metabolites, and irradiation causes dermatitis and sometimes causes skin ulcer in the irradiated site. We analyzed the relationships between the value of oxidative metabolites and skin reactions. A certain doses of radiation were irradiated to the right thigh of rats, and oxidative metabolites of rat's blood from caudal vein were measured by d-reactive oxygen metabolites (ROMs) test using an exclusive device. Skin reactions were evaluated according to a skin-reaction grading system from the day before irradiation to day 38 after irradiation. As a results, a significant correlation was shown between irradiation dose and skin grade. And a significant correlation was also shown between the value of oxidative metabolites and irradiation dose. The increase in oxidative metabolites was seen in the Day 16 after irradiation, and that corresponded with the appearance of skin reaction. It was suggested that the value of oxidative metabolites seems to be useful for estimating degree of skin reaction and time to appear skin reaction after irradiation. (author)

Gamma-radiation induced cross-links in ethylene-propylene rubber studied by CP-MAS NMR

International Nuclear Information System (INIS)

Sohma, J.; Shiotani, M.; Murakami, S.

1983-01-01

A new technique of 13 C-NMR, the CP-MAS method, was applied to study a chemistry of cross-links induced by #betta#-irradiation of ethylene-propylene rubber. The chemical species of cross-linking points were specified with their relative concentrations by the analysis of the CP-MAS spectra obtained before and after the irradiation. It was found that the short branches were also formed by the irradiation. A comparison was made between the cross-links detected by the CP-MAS method and those obtained by the Charlesby-Pinner analysis of the gelation caused by the #betta#-irradiation. The conventional 13 C-NMR of the cross-linked and swollen EPR provided us an information on the sol parts of the sample but little information on the cross-links in the gel parts. (author)

Phase stability of oxide dispersion-strengthened ferritic steels in neutron irradiation

International Nuclear Information System (INIS)

Yamashita, S.; Oka, K.; Ohnuki, S.; Akasaka, N.; Ukai, S.

2002-01-01

Oxide dispersion-strengthened ferritic steels were irradiated by neutrons up to 21 dpa and studied by microstructural observation and microchemical analysis. The original high dislocation density did not change after neutron irradiation, indicating that the dispersed oxide particles have high stability under neutron irradiation. However, there is potential for recoil resolution of the oxide particles due to ballistic ejection at high dose. From the microchemical analysis, it was implied that some of the complex oxides have a double-layer structure, such that TiO 2 occupied the core region and Y 2 O 3 the outer layer. Such a structure may be more stable than the simple mono-oxides. Under high-temperature irradiation, Laves phase was the predominant precipitate occurring at grain boundaries α phase and χ phase were not observed in this study

[Complex formation between alpha-chymotrypsin and block copolymers based on ethylene and propylene oxide, induced by high pressure].

Science.gov (United States)

Topchieva, I N; Sorokina, E M; Kurganov, B I; Zhulin, V M; Makarova, Z G

1996-06-01

A new method of formation of non-covalent adducts based on an amphiphilic diblock copolymer of ethylene and propylene oxides with molecular mass of 2 kDa and alpha-chymotrypsin (ChT) under high pressure, has been developed. The composition of the complexes corresponds to seven polymer molecules per one ChT molecule in the pressure range of 1.1 to 400 MPa. The complexes fully retain the catalytic activity. Kinetic constants (Km and kcat) for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester catalyzed by the complexes are identical with the corresponding values for native ChT. Analysis of kinetics of thermal inactivation of the complexes revealed that the constant of the rate of the slow inactivation step is markedly lower than for ChT.

Effects of irradiation on color and lipid oxidation of prosciutto

International Nuclear Information System (INIS)

Kong Qiulian; Qi Wenyuan; Yue Ling; Chen Zhijun; Bao Yingzi; Dai Xudong; Xu Yun

2012-01-01

This study dealt with the effect of irradiation on the color, irradiation odor and lipid oxidation of prosciutto crudo. The hams were irradiated by γ-ray and electronic beam (EB). Changes of color, irradiation odor, TBA value (TBARS), peroxide value (POV), carbonyl value and conjugated diene value were analyzed and compared with non-irradiated hams. Results showed that color index (a * ) of control, γ-ray irradiated and EB irradiated were 14.39, 9.45 and 11.71 respectively. The ratios of a * /b * were different with the type of rays. The ratio of a * /b * of EB irradiation was same with control, while that of γ-ray irradiation was decreased apparently. γ-ray irradiation had been shown to have apparently detrimental effect on the color and odor of hams, while EB irradiation had little detrimental effect. Irradiation increased POV and conjugated diene value, but the amounts of lipid oxidation products (TBARS, carbonyl value) were less than nonirradiated hams. (authors)

Conversion of 1,3-Propylene Glycol on Rutile TiO2(110)

Energy Technology Data Exchange (ETDEWEB)

Chen, Long; Li, Zhenjun; Smith, R. Scott; Kay, Bruce D.; Dohnalek, Zdenek

2014-10-09

The adsorption of 1,3-propylene glycol (1,3-PG) on partially reduced TiO2(110) and its conversion to products have been studied by a combination of molecular beam dosing and temperature programmed desorption (TPD). When the Ti surface sites are saturated by 1,3-PG, ~80% of the molecules undergo further reactions to yield products that are liberated during the TPD ramp. In contrast to ethylene glycol (EG) and 1,2- propylene glycol (1,2-PG) that yield only alkenes and water at very low coverages (< 0.05 ML), two additional products, HCHO and C2H4, along with propylene (CH3CHCH2) and water are observed for 1,3-PG. Identical TPD line shapes and desorption yields for HCHO and C2H4 suggest that these products result from C-C bond cleavage and are coupled. At higher 1,3-PG coverages (> 0.1 ML), propanal (CH3CH2CHO) and two additional products, 1-propanol (CH3CH2CH2OH) and acrolein (CH2CHCHO), are observed. The desorption of 1-propanol is found to be coupled with the desorption of acrolein, suggesting that these products are formed by the disproportionation of two 1,3-PG molecules. The coverage dependent TPD results further show that propylene formation dominates at low coverages (< 0.3 ML), while the decomposition and disproportionation channels increase rapidly at higher coverages and reach yields comparable to that of propylene at the 1,3-PG saturation coverage of 0.5 ML. The observed surface chemistry clearly shows how the molecular structure of glycols influences their reaction pathways on oxide surfaces.

Effects of irradiation on color and lipid oxidation of prosciutto

International Nuclear Information System (INIS)

Kong Qiulian; Qi Wenyuan; Yue Ling; Chen Zhijun; Bao Yingzi; Dai Xudong; Xu Yun

2011-01-01

This study dealt with the effect of irradiation on the color, ordor and lipid oxidation of prosciutto crudo. The hams were irradiated by γ-ray and electronic beam (EB). Changes of color, ordor, TBA value (TBARS), peroxide value (POV), carbonyl value and conjugated diene value were analyzed and compared with nonirradiated hams. Results showed that color index (a * ) of control, γ-ray irradiated and EB irradiated were 14.39, 9.45 and 11.71 respectively. γ-ray irradiation had been shown to have apparently detrimental effect on the color and ordor of hams, while EB irradiation had little detrimental effect. Irradiation increased POV and conjugated diene value, but the amounts of lipid oxidation products (TBARS, carbonyl value) were less than nonirradiated hams. (authors)

SCC-TB, DFT/B3LYP, MP2, AM1, PM3 and RHF study of ethylene oxide and propylene oxide structures, VA and VCD spectra

DEFF Research Database (Denmark)

Jalkanen, Karl J.; Frimand, Kenneth

2002-01-01

-binding method for equilibrium structures, VA and VCD spectra of ethylene oxide and propylene oxide in the gas-phase. Comparison to conventional methods AM1, PM3, MP2, RHF and DFT/B3LYP is carried out. We report results over a wider range of frequencies than previous work. In particular, we find indications...... that the self-consistent-charge tight-binding method, combined with DFT/B3LYP atomic polar tensors and atomic axial tensors, compares favourably with competing methods tendency to overestimate the location of spectral peaks with respect to frequencies, the latter observation being most pronounced in the higher...... frequency regions. Our findings produce additional support for the self-consistent-charge tight-binding method as a fast computational method for small and larger molecules, however, also that improved parameterisations are needed to reach accuracies of MP2 and DFT/B3LYP. (C) 2002 Elsevier Science B.V. All...

Effect of soy sauce on lipid oxidation of irradiated pork patties

International Nuclear Information System (INIS)

Kim, Hyun-Wook; Hwang, Ko-Eun; Choi, Yun-Sang; Choi, Ji-Hun; Lee, Mi-Ai; Song, Dong-Heon; Kim, Hack-Youn; Lee, Ju-Woon; Kim, Cheon-Jei

2013-01-01

This study was conducted to find out the antioxidant effect of the soy sauce on lipid oxidation of electron beam irradiated pork patties. The pork patties prepared with sodium chloride or soy sauce solution at identical salt concentrations were irradiated at 0 or 5 kGy, and peroxide value, conjugated diene, 2-thiobarbituric acid, and free fatty acid values were evaluated for 10 days (4 °C). The irradiated pork patties treated with soy sauce showed the lowest peroxide value and 2-thiobarbituric acid value at the end of storage compared to those prepared with sodium chloride. The irradiated pork patties formulated with soy sauce and 0.5% ascorbic acid had similar 2-thiobarbituric acid and free fatty acid values compared to those of the non-irradiated pork patties treated with sodium chloride. Our results suggested that the soy sauce can retard the lipid oxidation of irradiated pork patty, and a synergistic effect between soy sauce and ascorbic acid was observed. - Highlights: • Antioxidant effect of soy sauce on irradiated pork patties was studied. • The soy sauce can retard lipid oxidation of the irradiated pork patties. • A synergistic effect of ascorbic acid for preventing lipid oxidation was observed

Study of bixin oxidation by ionizing irradiation

International Nuclear Information System (INIS)

Fonseca, Thais N.; Teixeira, Paula S.; Moura, Eduardo de; Geraldo, Áurea Beatriz C.

2017-01-01

Brazil is the world's largest producer of anatto, followed by Kenya and Peru. The fruit of the annatto tree is constituted by a capsule containing external spines and internal seeds with reddish coloration, providing a natural pigment which is environmentally efficient, being able to replace synthetic pigments and dyes. The active substance of the pigment is Bixin, which is a type of carotenoid which constitutes a greater percentage of pigment in these seeds and has a lipo soluble character. Bixin reacts with NaOH in a saponification reaction giving norbixin, which is water soluble. It is known that the destination of the dye extracted from the fruit is intended for industry, especially the food industry. The culture of annatto tree brings prospects of development in agricultural programs for medium and small producers, which are able to use decadent areas of other crops. In addition to the food sector, new applications for the pigment helps the development of family farming. The pigment extracted from annatto undergoes a natural oxidation; this work aims to evaluate this phenomenon and also the oxidation of the pigment after the irradiation process. This work also evaluates of the how the oxidation process is affected by irradiation and the modifications introduced to irradiated pigments. Irradiated and nonirradiated samples were characterized by thermogravimetry, UV-vis spectrophotometry and infrared spectroscopy (FTIR). The results are then discussed. (author)

Oxide glass structure evolution under swift heavy ion irradiation

International Nuclear Information System (INIS)

Mendoza, C.; Peuget, S.; Charpentier, T.; Moskura, M.; Caraballo, R.; Bouty, O.; Mir, A.H.; Monnet, I.; Grygiel, C.; Jegou, C.

2014-01-01

Highlights: • Structure of SHI irradiated glass is similar to the one of a hyper quenched glass. • D2 Raman band associated to 3 members ring is only observed in irradiated glass. • Irradiated state seems slightly different to an equilibrated liquid quenched rapidly. - Abstract: The effects of ion tracks on the structure of oxide glasses were examined by irradiating a silica glass and two borosilicate glass specimens containing 3 and 6 oxides with krypton ions (74 MeV) and xenon ions (92 MeV). Structural changes in the glass were observed by Raman and nuclear magnetic resonance spectroscopy using a multinuclear approach ( 11 B, 23 Na, 27 Al and 29 Si). The structure of irradiated silica glass resembles a structure quenched at very high temperature. Both borosilicate glass specimens exhibited depolymerization of the borosilicate network, a lower boron coordination number, and a change in the role of a fraction of the sodium atoms after irradiation, suggesting that the final borosilicate glass structures were quenched from a high temperature state. In addition, a sharp increase in the concentration of three membered silica rings and the presence of large amounts of penta- and hexacoordinate aluminum in the irradiated 6-oxide glass suggest that the irradiated glass is different from a liquid quenched at equilibrium, but it is rather obtained from a nonequilibrium liquid that is partially relaxed by very rapid quenching within the ion tracks

Production of the oxidation-resistant polypropylene track membranes

International Nuclear Information System (INIS)

Kravets, L.I.; Dmitriev, S.N.; Apel, P.Y.

1999-01-01

This paper describes results of the method of manufacturing the polypropylene track membranes produced by physicochemical treatment under irradiation of accelerated heavy ions of polymer films. The developed method allows to produce membranes 0.1 - 0.2 μm in diameter and more with an improved structural and physicochemical properties. Poly-propylene track membranes of a novel sample are characterized by high homogeneity of pore sizes in magnitude, considerable mechanical strength, advanced thermal stability and resistance to oxidation in aggressive media. It opens new fields for their usage

Irradiation test plan of oxidation-resistant graphite in WWR-K Research Reactor

International Nuclear Information System (INIS)

Sumita, Junya; Shibata, Taiju; Sakaba, Nariaki; Osaki, Hirotaka; Kato, Hideki; Fujitsuka, Kunihiro; Muto, Takenori; Gizatulin, Shamil; Shaimerdenov, Asset; Dyussambayev, Daulet; Chakrov, Petr

2014-01-01

Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR) which is a graphite-moderated and helium gas-cooled reactor. In the case of air ingress accident in HTGR, SiO_2 protective layer is formed on the surface of SiC layer in TRISO CFP and oxidation of SiC does not proceed and fission products are retained inside the fuel particle. A new safety concept for the HTGR, called Naturally Safe HTGR, has been recently proposed. To enhance the safety of Naturally Safe HTGR ultimately, it is expected that oxidation-resistant graphite is used for graphite components to prevent the TRISO CFPs and fuel compacts from failure. SiC coating is one of candidate methods for oxidation-resistant graphite. JAEA and four graphite companies launched R&Ds to develop the oxidation-resistant graphite and the International Science and Technology Center (ISTC) partner project with JAEA and INP was launched to investigate the irradiation effects on the oxidation-resistant graphite. To determine grades of the oxidation-resistant graphite which will be adopted as irradiation test, a preliminary oxidation test was carried out. This paper described the results of the preliminary oxidation test, the plan of out-of-pile test, irradiation test and post-irradiation test (PIE) of the oxidation-resistant graphite. The results of the preliminary oxidation test showed that the integrity of the oxidation resistant graphite was confirmed and that all of grades used in the preliminary test can be adopted as the irradiation test. Target irradiation temperature was determined to be 1473 (K) and neutron fluence was determined to be from 0.54 × 10"2"5through 1.4 × 10"2"5 (/m"2, E>0.18MeV). Weight change, oxidation rate, activation energy, surface condition, etc. will be evaluated in out-of-pile test and weight change, irradiation effect on oxidation rate and activation energy, surface condition, etc. will be evaluated in PIE. (author)

Double photoionization of propylene oxide: A coincidence study of the ejection of a pair of valence-shell electrons

Science.gov (United States)

Falcinelli, Stefano; Vecchiocattivi, Franco; Alagia, Michele; Schio, Luca; Richter, Robert; Stranges, Stefano; Catone, Daniele; Arruda, Manuela S.; Mendes, Luiz A. V.; Palazzetti, Federico; Aquilanti, Vincenzo; Pirani, Fernando

2018-03-01

Propylene oxide, a favorite target of experimental and theoretical studies of circular dichroism, was recently discovered in interstellar space, further amplifying the attention to its role in the current debate on protobiological homochirality. In the present work, a photoelectron-photoion-photoion coincidence technique, using an ion-imaging detector and tunable synchrotron radiation in the 18.0-37.0 eV energy range, permits us (i) to observe six double ionization fragmentation channels, their relative yields being accounted for about two-thirds by the couple (C2H4+, CH2O+) and one-fifth by (C2H3+, CH3O+); (ii) to measure thresholds for their openings as a function of photon energy; and (iii) to unravel a pronounced bimodality for a kinetic-energy-released distribution, fingerprint of competitive non-adiabatic mechanisms.

Establishment of evaluation system for oxidation/anti-oxidation in living organisms using radiation irradiation and its practical application

International Nuclear Information System (INIS)

Umegaki, Keizo

2000-01-01

Basic study on the degree of oxidation damages after X-ray irradiation and changes in the anti-oxidative defense action was made using the rat. In addition, amplification of trace DNA damages by X-ray irradiation was investigated with human lymphocytes. Wistar rats were exposed to X-ray at 3 Gy under no anesthetization and killed after various time after the irradiation. The content of vitamin C, an anti-oxidant vitamin C in the bone marrow was markedly reduced by X-ray irradiation and the content after 24 hours from the irradiation was about 2% of that of the unexposed group. The content of vitamin E in the bone marrow was ca. 43% of that of the unexposed group. However, the contents of these anti-oxidant vitamins gradually recovered from 3-4 days after the irradiation. On the other hand, the content of 4-hydroxynonenal among the aldehydes that were tested as the indicator for oxidation damage of lipid was significantly increased one day after the irradiation and the contents of hexanal and TBARS reached the maximum level 3 days after. However, daily administration of about 100-fold larger amount of vitamin E (α-tocopherol at 460 mg/kg) for 3 days before the irradiation resulted in an increase in its content in the bone marrow, but significant decreases in the vitamin E and C levels in the bone marrow 24 hours after X-ray irradiation and aldehyde contents were increased, suggesting that pre-irradiation administration of vitamin E has no effects on the damages of bone marrow cells. As an indicator of DNA damages, the rate of appearance for lymphocytes having micronuclei was determined. The number of such lymphocytes was not significantly changed by exercise, but the number after irradiation at 1.5 Gy was dose dependently increased. These results suggested that trace DNA oxidation damages produced by severe exercise were markedly amplified by X-ray irradiation in not-trained subjects. (M.N.)

Oxidation kinetic changes of UO2 by additive addition and irradiation

International Nuclear Information System (INIS)

You, Gil-Sung; Kim, Keon-Sik; Min, Duck-Kee; Ro, Seung-Gy

2000-01-01

The kinetic changes of air-oxidation of UO 2 by additive addition and irradiation were investigated. Several kinds of specimens, such as unirradiated-UO 2 , simulated-UO 2 for spent PWR fuel (SIMFUEL), unirradiated-Gd-doped UO 2 , irradiated-UO 2 and -Gd-doped UO 2 , were used for these experiments. The oxidation results represented that the kinetic patterns among those samples are remarkably different. It was also revealed that the oxidation kinetics of irradiated-UO 2 seems to be more similar to that of unirradiated-Gd-doped UO 2 than that of SIMFUEL

Magnetization measurements and XMCD studies on ion irradiated iron oxide and core-shell iron/iron-oxide nanomaterials

Energy Technology Data Exchange (ETDEWEB)

Kaur, Maninder; Qiang, You; Jiang, Weilin; Pearce, Carolyn; McCloy, John S.

2014-12-02

Magnetite (Fe3O4) and core-shell iron/iron-oxide (Fe/Fe3O4) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si2+ ions and the structures determined by x-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, x-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe3+ than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack the signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite, so it is likely that FeO exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe3O4 sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe3O4 sample are due to interfaces and interactions between grains which were not present in samples before irradiation as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.

International thermodynamic tables of the fluid state propylene (propene)

CERN Document Server

Angus, S; De Reuck, K M

2013-01-01

International Thermodynamic Tables of the Fluid State - 7 Propylene (Propene) is a compilation of internationally agreed values of the equilibrium thermodynamic properties of propylene. This book is composed of three chapters, and begins with the presentation of experimental result of thermodynamic studies compared with the equations used to generate the tables. The succeeding chapter deals with correlating equations for thermodynamic property determination of propylene. The last chapter provides the tabulations of the propylene's thermodynamic properties and constants. This book will prove

The Evonik-Uhde HPPO process for proplene oxide production

Energy Technology Data Exchange (ETDEWEB)

Jaeger, B.; Baerz, M. [Evonik Industries, Hanau (Germany); Schemel, J.; Kolbe, B. [Uhde GmbH, Dortmund/Bad Soden (Germany)

2011-07-01

In 2008 the HPPO technology has shown up as an economically and environmentally friendly alternative for manufacturing of propylene oxide. The HPPO technology offers the advantage of an on purpose process for manufacturing of propylene oxide without dependency on disposal or marketing of coupling products. (orig.)

Enhanced propylene production in FCC by novel catalytic materials

Energy Technology Data Exchange (ETDEWEB)

Kelkar, C.P.; Harris, D.; Xu, M.; Fu, J. [BASF Catalyst LLC, Iselin, NJ (United States)

2007-07-01

Fluid catalytic cracking is expected to increasingly supply the additional incremental requirements for propylene. The most efficient route to increase propylene yield from an FCC unit is through the use of medium pore zeolites such as ZSM-5. ZSM-5 zeolite cracks near linear olefins in the gasoline range to LPG olefins such as propylene and butylenes. This paper will describe catalytic approaches to increase gasoline range olefins and the chemistry of ZSM-5 to crack those olefins. The paper will also describe novel catalytic materials designed to increase propylene. (orig.)

Evolution of zirconium-based precipitates during oxidation and irradiation of Zr alloys (impact on the oxidation kinetics of Zr alloys)

International Nuclear Information System (INIS)

Pecheur, Dominique

1993-01-01

As the oxidation of the zircaloy sheath is one of the factors which limit the lifetime of nuclear fuel rods, this research thesis aims at a better knowledge of the involved oxidation mechanisms and to improve the oxidation resistance in order to increase rod lifetime. Oxidation test performed in autoclave to study zirconium alloy oxidation without irradiation showed that oxidation kinetics is significantly higher under irradiation. This difference is attributed to a different evolution of the sheath material under irradiation. Thus, this research focused on the role of precipitates in the oxidation process of zirconium alloys, and on the impact of their amorphization on this oxidation. After a detailed description of the context and of the various implemented experimental means, the author presents the results obtained on a reference material on the one hand, and on a material irradiated by ions or neutrons on the other hand. More particularly, the author studied in these both cases the introduction of precipitates in the oxide layer by transmission electronic microscopy, and oxidation kinetics obtained in autoclave on these two types of material. He reports the analysis of the introduction of precipitates in the oxide layer formed on the reference material. He proposes interpretations for the evolutions of structure and of chemical compositions of precipitates in the oxide layer. These observations are then correlated with oxidation kinetics in these alloys. Finally, the author discusses results of oxidation tests obtained on materials irradiated by ions and by neutrons [fr

Experimental studies on anti-oxidants reducing lipid peroxidation of irradiated mice

International Nuclear Information System (INIS)

Du Zeji; Liu Keliang; Su Liaoyuan

1993-08-01

The free radical plays an important role in the irradiation damage. The irradiation damage would be reduced if anti-oxidants is used, because anti-oxidants can scavenge free radicals and suppress lipid peroxidation. In the study, a fluoro-spectrophotometer was used to determine the changes of MDA levels in mice tissues and serum after irradiation and the protective effect of anti-oxidants of Vit E and DMSO on damage caused by free radicals. The results are as follows: (1) The highest MDA level was at 12 to 24 hours after irradiation dose of 3.0 Gy. (2) The MDA level is increasing with the increasing of irradiation dose. It means the MDA level can indicate the extent of irradiation damage. (3) Both Vit E and DMSO had a powerful effect on reducing MDA level, but the effect of DMSO was stronger than Vit E. The optimum doses of them were 0.25 mg/g body weight and 10 mg/g body weight respectively. (4) The best effect obtained was to use Vit E and DMSO simultaneously

Poly(propylene carbonate): Insight into the Microstructure and Enantioselective Ring-Opening Mechanism

KAUST Repository

Salmeia, Khalifah A.

2012-11-13

Different poly(propylene carbonate) (PPC) microstructures have been synthesized from the alternating copolymerization of CO 2 with both racemic propylene oxide (PO) and various mixtures of PO enantiomers using chiral salen catalysts. The microstructures of the obtained copolymers as a function of polymerization time have been analyzed by a combination of chiral GC and high-resolution NMR spectroscopy. The 13C NMR spectra of selected poly(propylene carbonate) samples were recorded using a 900 MHz ( 1H) spectrometer, showing a previously unreported fine splitting of the carbonate resonances. This allowed a detailed assignment of signals for various copolymer microstructures taking into account the specifics in their stereo- and regioirregularities. For example, the enantioselectivity preference of the (R,R-salen)Co catalyst for (S)-PO at the beginning of the copolymerization leads predominantly to (S)-PO insertion, with any (R)-PO misinsertion being followed by incorporation of (S)-PO, so that the microstructure features isolated stereoerrors. K rel calculations for the copolymerization showed around 5-fold enantioselectivity for (S)-PO over (R)-PO at short reaction time. Analysis of the copolymer microstructures obtained under various reaction conditions appears to be an additional approach to differentiate the occurrence of bimetallic and bifunctional copolymerization mechanisms that are widely discussed in the literature. © 2012 American Chemical Society.

Poly(propylene carbonate): Insight into the Microstructure and Enantioselective Ring-Opening Mechanism

KAUST Repository

Salmeia, Khalifah A.; Vagin, Sergei; Anderson, Carly E.; Rieger, Bernhard

2012-01-01

Different poly(propylene carbonate) (PPC) microstructures have been synthesized from the alternating copolymerization of CO 2 with both racemic propylene oxide (PO) and various mixtures of PO enantiomers using chiral salen catalysts. The microstructures of the obtained copolymers as a function of polymerization time have been analyzed by a combination of chiral GC and high-resolution NMR spectroscopy. The 13C NMR spectra of selected poly(propylene carbonate) samples were recorded using a 900 MHz ( 1H) spectrometer, showing a previously unreported fine splitting of the carbonate resonances. This allowed a detailed assignment of signals for various copolymer microstructures taking into account the specifics in their stereo- and regioirregularities. For example, the enantioselectivity preference of the (R,R-salen)Co catalyst for (S)-PO at the beginning of the copolymerization leads predominantly to (S)-PO insertion, with any (R)-PO misinsertion being followed by incorporation of (S)-PO, so that the microstructure features isolated stereoerrors. K rel calculations for the copolymerization showed around 5-fold enantioselectivity for (S)-PO over (R)-PO at short reaction time. Analysis of the copolymer microstructures obtained under various reaction conditions appears to be an additional approach to differentiate the occurrence of bimetallic and bifunctional copolymerization mechanisms that are widely discussed in the literature. © 2012 American Chemical Society.

Radon in propylene : unexpected influence of NORM in a chemical plant

International Nuclear Information System (INIS)

Scarnichia, Eduardo; Etchepareborda, Andres; Arribere, Maria

2008-01-01

This paper describes an incident in a polypropylene plant caused by NORM material, 222 Rn and its daughters; the measurements conducted to determine radon concentration in propylene; the determination of the maximum allowable concentration to operate and the radiation protection issues implied. The growing world demand on polypropylene makes necessary follow the research on the subject. The problems of radon in natural gas, and propane are well known, but there is less information on propylene. The aim of this paper is contribute to overcome this drawback. Propylene is one of the fastest growing petrochemicals, driven primarily by the high growth rate of polypropylene. Polypropylene demand is currently growing in the U.S. at 6 %/yr, and in some regions of the world the growth rate is considerably higher. While steam cracking continues to supply most of the world's propylene, there is an increasing need for propylene from other sources. The growth in steam cracker capacity is driven by the need for ethylene, and co-product propylene production is not keeping up with propylene demand growth. New on-purpose propylene technologies will be required to provide the additional supplies of propylene needed to meet the growth projections. Several on-purpose propylene technologies are available, such as propane dehydrogenation. Remembering that most of the radon follows propane, in the case of propane dehydrogenation the radon concentration in propylene will be very much higher. This world tendency, together with still unclear issues, makes necessary to keep an eye on the subject. (author)

78 FR 20032 - Styrene-Ethylene-Propylene Block Copolymer; Tolerance Exemption

Science.gov (United States)

2013-04-03

...-Ethylene-Propylene Block Copolymer; Tolerance Exemption AGENCY: Environmental Protection Agency (EPA... for residues of styrene-ethylene-propylene block copolymer (CAS Reg. No. 108388-87-0) when used as an...-ethylene-propylene block copolymer on food or feed commodities. DATES: This regulation is effective April 3...

TL response to quartz and aluminum oxide grain for α-irradiation

International Nuclear Information System (INIS)

Pan Baolin; Wei Mingjian; Li Dongxu; Liu Zhaowen; Liu Chao; Zhao Shiyuan

2009-01-01

Thermoluminescence (TL) response for an α-ray irradiation system ( 241 Am) was examined with quartz grains of 11-40 μm. Quartz grains of different sizes, i.e. 137 Cs), before they were irradiated to different doses by the α-ray irradiation system. TL response to the quartz grain samples was measured. TL response of the quartz grains smaller than 4 μm and 11-40 μm to α-ray irradiation is the best, as the α-rays cannot penetrate quartz larger than 40 μm. The TL response characteristic is related with quartz grain surface area. TL responses to α-irradiation of 11-40 μm quartz and aluminum oxide grains were compared. The α-irradiation TL response of aluminum oxide (330 degree C) is better than the quartz (375 degree C). (authors)

Effect of irradiation on lipid oxidation in eviscerated chicken carcasses during storage

International Nuclear Information System (INIS)

Hassan, I.M.; Hussein, M.F.; Mahmoud, A.A.; Hegazy, R.A.

1988-01-01

Oxidative changes induced in pectoralis major muscle of chicken after irradiation treatments with 0,6,10 and 20 KGy in both non frozen or frozen conditions during subsequent storage were investigated. Ultraviolet (UV) absorption, peroxides and thiobarbituric reactive substances increased in chicken lipids with increasing irradiation doses. These oxidative changes are greater in irradiated refrigerated (4 ± 1°C) than in irradiated frozen (-20°C) chicken lipids during storage. It was found the peroxides and TBA reactive substances do not accumulate as a stable end products of fat oxidation but reach a maximum during storage followed by gradual declining. The UV absorption provides an objective measure of chicken lipids autoxidation suitable for following the progress of autoxidation of irradiated chicken during subsequent non frozen (4 ± 1°C) or frozen (-20°C) storage. The extent of Maillard-like browning was followed in both unirradiated and irradiated samples during storage. All tested objective parameters correlated well with sensory assessment of odour particularly when irradiation dose was increased as well as in frozen samples

Kinetic modelling of radiochemical ageing of ethylene-propylene copolymers

International Nuclear Information System (INIS)

Colin, Xavier; Richaud, Emmanuel; Verdu, Jacques; Monchy-Leroy, Carole

2010-01-01

A non-empirical kinetic model has been built for describing the general trends of radiooxidation kinetics of ethylene-propylene copolymers (EPR) at low γ dose rate and low temperature. It is derived from a radical chain oxidation mechanism composed of 30 elementary reactions: 19 relative to oxidation of methylene and methyne units plus 11 relative to their eventual cooxidation. The validity of this model has been already checked successfully elsewhere for one homopolymer: polyethylene (PE) (; ). In the present study, it is now checked for polypropylene (PP) and a series of three EPR differing essentially by their mole fraction of ethylene (37%, 73% and 86%) and their crystallinity degree (0%, 5% and 26%). Predicted values of radiation-chemical yields are in good agreement with experimental ones published in the last half past century.

Effects of diet, packaging, and irradiation on protein oxidation, lipid oxidation, and color of raw broiler thigh meat during refrigerated storage.

Science.gov (United States)

Xiao, S; Zhang, W G; Lee, E J; Ma, C W; Ahn, D U

2011-06-01

This study was designed to evaluate the effects of dietary treatment, packaging, and irradiation singly or in combination on the oxidative stability of broiler chicken thigh meat. A total of 120 four-week-old chickens were divided into 12 pens (10 birds/pen), and 4 pens of broilers were randomly assigned to a control oxidized diet (5% oxidized oil) or an antioxidant-added diet [500 IU of vitamin E + 200 mg/kg of butylated hydroxyanisole (BHA)] and fed for 2 wk. After slaughter, thigh meats were separated, ground, packaged in either oxygen-permeable or oxygen-impermeable vacuum bags, and irradiated at 0 or 3 kGy. Lipid oxidation (TBA-reactive substances), protein oxidation (carbonyl), and color of the meat were measured at 1, 4, and 7 d of refrigerated storage. The lipid and protein oxidation of thigh meats from birds fed the diet supplemented with antioxidants (vitamin E + BHA) was significantly lower than the lipid and protein oxidation of birds fed the control diet, whereas the lipid and protein oxidation of broilers fed the oxidized oil diet was higher than that of birds fed the control diet. Vacuum packaging slowed, but irradiation accelerated, the lipid and protein oxidation of thigh meat during storage. Dietary antioxidants (vitamin E + BHA) and irradiation treatments showed a stronger effect on lipid oxidation than on protein oxidation. A significant correlation between lipid and protein oxidation in meat was found during storage. Dietary supplementation of vitamin E + BHA and the irradiation treatment increased the lightness and redness of thigh meat, respectively. It is suggested that appropriate use of dietary antioxidants in combination with packaging could be effective in minimizing oxidative changes in irradiated raw chicken thigh meat.

Isolation and Characterization of PHA-Producing Bacteria from Propylene Oxide Saponification Wastewater Residual Sludge.

Science.gov (United States)

Li, Ruirui; Gu, Pengfei; Fan, Xiangyu; Shen, Junyu; Wu, Yulian; Huang, Lixuan; Li, Qiang

2018-03-21

A polyhydroxyalkanoate (PHA)-producing strain was isolated from propylene oxide (PO) saponification wastewater activated sludge and was identified as Brevundimonas vesicularis UJN1 through 16S rDNA sequencing and Biolog microbiological identification. Single-factor and response surface methodology experiments were used to optimize the culture medium and conditions. The optimal C/N ratio was 100/1.04, and the optimal carbon and nitrogen sources were sucrose (10 g/L) and NH 4 Cl (0.104 g/L) respectively. The optimal culture conditions consisted of initial pH of 6.7 and an incubation temperature of 33.4 °C for 48 h, with 15% inoculum and 100 mL medium at an agitation rate of 180 rpm. The PHA concentration reached 34.1% of the cell dry weight and increased three times compared with that before optimization. The only report of PHA-producing bacteria by Brevundimonas vesicularis showed that the conversion rate of PHAs using glucose as the optimal carbon source was 1.67%. In our research, the conversion rate of PHAs with sucrose as the optimal carbon source was 3.05%, and PHA production using sucrose as the carbon source was much cheaper than that using glucose as the carbon source.

Improvement of biological properties of titanium by anodic oxidation and ultraviolet irradiation

Energy Technology Data Exchange (ETDEWEB)

Li, Baoe [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Li, Ying [Stomatological Hospital, Tianjin Medical University, Tianjin 300070 (China); Li, Jun [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Fu, Xiaolong; Li, Changyi [Stomatological Hospital, Tianjin Medical University, Tianjin 300070 (China); Wang, Hongshui [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Liu, Shimin [Business School, Tianjin University of Commerce, Tianjin 300134 (China); Guo, Litong [China University of Mining and Technology, Xuzhou 221116 (China); Xin, Shigang [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Liang, Chunyong, E-mail: liangchunyong@126.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Li, Haipeng, E-mail: lhpcx@163.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China)

2014-07-01

Anodic oxidation was applied to produce a homogeneous and uniform array of nanotubes of about 70 nm on the titanium (Ti) surface, and then, the nanotubes were irradiated by ultraviolet. The bioactivity of the Ti surface was evaluated by simulated body fluid soaking test. The biocompatibility was investigated by in vitro cell culture test. The results showed that bone-like apatite was formed on the anodic oxidized and UV irradiated Ti surface, but not on the as-polished Ti surface after immersion in simulated body fluid for two weeks. Cells cultured on the anodic oxidized Ti surface showed enhanced cell adhesion and proliferation, also presented an up-regulated gene expression of osteogenic markers OPG, compared to those cultured on the as-polished Ti surface. After UV irradiation, the cell behaviors were further improved, indicating better biocompatibility of Ti surface. Based on these results, it can be concluded that anodic oxidation improved the biological properties (bioactivity and biocompatibility) of Ti surface, while UV irradiation improved the biocompatibility to a better extent. The improved biological properties were attributed to the nanostructures as well as the enhanced hydrophilicity. Therefore, anodic oxidation combined with UV irradiation can be used to enhance the biological properties of Ti-based implants.

Stability under irradiation of a fine dispersion of oxides in a ferritic matrix

International Nuclear Information System (INIS)

Monnet, I.

1999-01-01

Oxide dispersion strengthened (ODS) ferritic-martensitic steels are being considered for high temperature, high fluence nuclear applications, like fuel pin cladding in Fast Breeder Reactors. ODS alloys offer improved out of pile strength characteristics at temperature above 550 deg.C and ferritic-martensitic matrix is highly swelling resistant. A clad in an ODS ferritic steel, call DY (Fe-13Cr-1,5Mo+TiO 2 +Y 2 O 3 ) has been irradiated in the experimental reactor Phenix. Under irradiation oxide dissolution occurs. Microstructural observations indicated that oxide evolution is correlated with the dose and consist in four phenomena: the interfaces of oxide particles with the matrix become irregular, the uniform distribution of the finest oxide ( 2 O 3 , Y 2 O 3 , MgO or MgAl 2 O 4 . These materials were irradiated with charged particles in order to gain a better understanding of the mechanisms of dissolution. Irradiation with 1 MeV Helium does not induce any modification, neither in the chemical modification of the particles nor in their spatial and size distribution. Since most of the energy of helium ions is lost by inelastic interaction, this result proves that this kind of interaction does not induce oxide dissolution. Irradiation with 1 MeV or 1.2 MeV electrons leads to a significant dissolution with a radius decrease proportional to the dose. These experiments prove that oxide dissolution can be induced by Frenkel pairs alone, provided that metallic atoms are displaced. The comparison between irradiation with ions (displacements cascades) and electrons (Frenkel pairs only) shows the importance of free point defects in the dissolution phenomena. For all the irradiations (ions or electrons) the spinel MgAl 2 O 4 seems more resistant than Y 2 O 3 to dissolution, and MgO and Al 2 O 3 are even less resistant. This is the order of stability under irradiation of bulk oxides. (author)

Radio-oxidation of an EPDM elastomer under weak or strong ionising radiations: measurement and modelling of dioxygen consumption; Radio-oxydation d'un elastomere de type EPDM lors d'irradiations faiblement ou fortement ionisantes: mesure et modelisation de la consommation de dioxygene

Energy Technology Data Exchange (ETDEWEB)

Dely, N

2005-10-15

Usually, the irradiation of polymers under ionising radiations occurs in air that is in the presence of oxygen. This leads to a radio oxidation process and to oxygen consumption. Our material is an EPDM elastomer (ethylene propylene 1,4 hexadiene) used as insulator in control-command cables in nuclear plants (Pressurised Water Reactor). A specific device has been conceived and built up during this PhD work for measuring very small oxygen consumptions with an accuracy of around 10%. Ionising radiations used are electrons at 1 MeV and carbon ions at 11 MeV per nucleon. Under both electron and ion irradiations, the influence of oxygen pressure on oxygen consumption has been studied in a very large range: between 1 and 200 mbar. In both cases, the yield of oxygen consumption is constant in-between 200 and 5 mbar. Then, at lower pressures, it decreases appreciably. On the other hand, the oxygen consumption during ion irradiation is four times smaller than during electron irradiation. This emphasizes the role of the heterogeneity of the energy deposition at a nano-metric scale. The adjustment of the experimental results obtained during electron irradiation with the general homogeneous steady-state kinetic model has allowed extracting all the values of the kinetic parameters for the chosen mechanism of radio oxidation. The knowledge of these numbers will allow us to face our results obtained during ion irradiation with a heterogeneous kinetic model under development. (author)

Modification of polymer blends by irradiation

International Nuclear Information System (INIS)

Zuchowska, D.; Zagorski, Z.P.

1999-01-01

Modification of polymers, especially of polyolefin-elastomer blends (e. g. ethylene/propylene/diene terpolymer, ethylene propylene copolymer, ethylene/vinyl acetate copolymer etc.), by irradiation with a beam of fast electrons is discussed. Irradiation of polymer blends usually results in enhanced interactions between the constituents, caused among other things, by grafting induced at the polymer interphase. As a result, mechanical properties are affected to an extent depending on the proportion and type of constituent polymers, stabilizer content and radiation dose. Breaking strength (σ) relative elongation at break (ε) and melt flow rate (MFR), were examined for a triblock styrene/butadiene/styrene (SBS) copolymer, polypropylene (PP), and a PP-SBS blend (50:50 by wt.). In PP, the content of the crystal phase was determined. Irradiation was found to make SBS crosslink, as a result, σ rose by 25% and ε remained unaffected. PP was found to become degraded upon irradiation (MFR rose as much as 16 times), thereby σ and ε decreased considerably. In pure PP, the content of the crystal phase was found to increase. The variations of σ and ε in the irradiated PP-SBS blend follow a tendency similar to that in the SBS copolymer examined. This fact suggests the SBS copolymer to have a decisive effect on the macroscopic properties of the PP-SBS blend. (author)

The effect of electron beam irradiation on lipid oxidation in sausages

Directory of Open Access Journals (Sweden)

atefeh yousefi

2017-09-01

Full Text Available Introduction: Irradiation treatment is one of the best techniques to extend the shelf-life of meat, without emerging the nutritional properties and sensory quality of irradiated meat products.  However electron -beam  may cause transformations in foods but has been known as to the most easily-applied irradiation technique in food industries. Electron-beam irradiation is an environment friendly, low cost and time effective alternative to other decontamination technologies. Lipid oxidation could produce of irradiated meat. This study aimed at evaluating the state of lipid oxidation of irradiated sausages. Its findings could help the control, improve food safety and quality properties to food industries. Methods: Sausages were purchased in a local supermarket, minced sausages blended for thiobarbituric acid reactive substances (TBARS analysis and divided into 25 g pieces. The samples including one control group and four case groups. Packaged sausage were exposed at doses of 0 (control, 1, 2, 3 and 5 kGy and analyzed on various days 0, 5, 10 and 30. Results: Thiobarbituric acid reactive substances (TBARS has increased as time goes on (P<0.05. A significant relationship was observed on different Doses. But, the maximum of TBARS was observed in 3 kGy. Conclusion: Utilizing of Electron-beam irradiation in low doses does not have significant difference on lipid oxidation. Irradiating of meat products by addition of antioxidants can minimize or avoid the development of rancidity.

Dose dependent oxidation kinetics of lipids in fish during irradiation processing

International Nuclear Information System (INIS)

Tukenmez, I.; Ersen, M.S.; Bakioglu, A.T.; Bicer, A.; Pamuk, V.

1997-01-01

Kinetic aspects of the development of lipid oxidation in complex foods as fish in the course of irradiation were analyzed with respect to the associated formation of malonaldehyde (MA) through the reactions modified so as to be consistent with those in complex foods as fish. Air-packed anchovy (Engraulis encrasicholus) samples in polyethylene pouches were irradiated at the doses of 1, 2, 5, 10, 15,20 and 25 kGy at 20 o C in a Cs-137 gamma irradiator of 1.806 kGy/h dose rate. Immediately after each irradiation, MA contents of irradiated and unirradiated samples were determined by thiobarbituric acid test. Based on the MA formation, a kinetic model to simulate the apparent oxidation of lipid in fish as a function of irradiation dose was derived from the rate equations consistent with modified reactions. Kinetic parameters and simulation were related to conditions of lipid oxidation, and associated rancidity state of fish with respect to the doses applied in different irradiation-preservation processes. Numerical values of kinetic parameters based on the MA formation were found as a threshold dose of 0.375 kGy, an apparent yield of 1.871 μmol/kg kGy, and a maximum attainable concentration of 15.853 μmol/kg which may be used for process control and dosimetry. (author)

Electron microscope study of irradiated beryllium oxide

International Nuclear Information System (INIS)

Bisson, A.A.

1965-06-01

The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. α) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10 19 , 9 x 10 19 and 2 x 10 20 n f cm -2 at a temperature below 100 deg. C. For the irradiation at 6 x 10 19 n f cm -2 , the defects are merely visible, but at 2 x l0 20 n f cm -2 the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [fr

Solubility of mixed monomers of tetrafluoroethylene and propylene in water and latex

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Okamoto, Jiro

1978-03-01

For kinetical analysis of the emulsion copolymerization of tetrafluoroethylene with propylene and selection of the optimum reaction conditions, the monomer concentrations and composition of the polymer particle were measured and the relations with reaction conditions were determined. Solubilities of tetrafluoroethylene and propylene in water increase with pressure. solubility of propylene is larger than that of tetrafluoroethylene. Solubility of the mixed monomers in water and latex increases with pressure and propylene concentration and decreases with temperature. Propylene concentration in the dissolved monomers is dependent on its concentration in the gas phase and independent of pressure and temperature. The monomer concentrations and the composition were estimated from measurements. Under propylene concentration in the gas phase of 0 to 40 wt % at 30 Kg/cm 2 G and 40 0 C, the monomer concentration and propylene fraction of the polymer particle are 17 -- 27% and 0 -- 62% respectively. The amount of propylene in the particle increases with its fraction in the gas phase, but the amount of tetrafluoroethylene is independent of its fraction in the gas phase. Monomer composition of the polymer particle is dependent on monomer composition of the gas phase and independent of temperature and pressure. The concentration in the polymer particle is 17% at propylene concentration 10 mole % in the gas phase. (auth.)

Irradiation temperature dependence of production efficiency of lattice defects in some neutron-irradiated oxides

International Nuclear Information System (INIS)

Okada, Moritami; Atobe, Kozo; Nakagawa, Masuo

2004-01-01

Temperature dependence of production efficiency of irradiation-induced defects in neutron-irradiated oxides has been investigated. Some oxide single crystals, MgO, α-Al 2 O 3 (sapphire) and TiO 2 (rutile), were irradiated at several controlled temperatures, 10, 20, 50, 100, 150 and 200 K, using the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL), and at ambient temperature (∼370 K) in the same facility. Irradiation temperature dependence of production efficiency of a 1 μm band in TiO 2 differs greatly from that of anion vacancy (F-type centers) in MgO and α-Al 2 O 3 . Results for MgO and α-Al 2 O 3 show steep negative gradients from 10 to 370 K, whereas that for TiO 2 includes a valley between 40 and 60 K and a hump at about 130 K, and then disappear at about 200 K. In MgO and α-Al 2 O 3 , this behavior can be explained by the recombination of Frenkel pairs, which is activated at higher temperature. In TiO 2 , in addition to the recombination mechanism, a covalent bonding property is thought to be exerted strong influence, and it is suggested that a disappearance of the 1 μm band at above 200 K is due to the recombination process of Frenkel pairs which is caused by the irradiation-induced crystallization

Irradiation temperature dependence of production efficiency of lattice defects in some neutron-irradiated oxides

Energy Technology Data Exchange (ETDEWEB)

Okada, Moritami [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 5900494 (Japan)]. E-mail: okada@rri.kyoto-u.ac.jp; Atobe, Kozo [Faculty of Science, Naruto University of Education, Naruto, Tokushima 7728502 (Japan); Nakagawa, Masuo [Faculty of Education, Kagawa University, Takamatsu, Kagawa 7608522 (Japan)

2004-11-01

Temperature dependence of production efficiency of irradiation-induced defects in neutron-irradiated oxides has been investigated. Some oxide single crystals, MgO, {alpha}-Al{sub 2}O{sub 3} (sapphire) and TiO{sub 2} (rutile), were irradiated at several controlled temperatures, 10, 20, 50, 100, 150 and 200 K, using the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL), and at ambient temperature ({approx}370 K) in the same facility. Irradiation temperature dependence of production efficiency of a 1 {mu}m band in TiO{sub 2} differs greatly from that of anion vacancy (F-type centers) in MgO and {alpha}-Al{sub 2}O{sub 3}. Results for MgO and {alpha}-Al{sub 2}O{sub 3} show steep negative gradients from 10 to 370 K, whereas that for TiO{sub 2} includes a valley between 40 and 60 K and a hump at about 130 K, and then disappear at about 200 K. In MgO and {alpha}-Al{sub 2}O{sub 3}, this behavior can be explained by the recombination of Frenkel pairs, which is activated at higher temperature. In TiO{sub 2}, in addition to the recombination mechanism, a covalent bonding property is thought to be exerted strong influence, and it is suggested that a disappearance of the 1 {mu}m band at above 200 K is due to the recombination process of Frenkel pairs which is caused by the irradiation-induced crystallization.

Electrochemical Interrogation of G3-Poly(propylene thiophenoimine Dendritic Star Polymer in Phenanthrene Sensing

Directory of Open Access Journals (Sweden)

Hlamulo R. Makelane

2015-09-01

Full Text Available A novel dendritic star-copolymer, generation 3 poly(propylene thiophenoimine (G3PPT-co-poly(3-hexylthiophene (P3HT star co-polymer on gold electrode (i.e., Au|G3PPT-co-P3HT was used as a sensor system for the determination of phenanthrene (PHE. The G3PPT-co-P3HT star co-polymer was synthesized via in situ electrochemical co-polymerization of generation 3 poly (propylene thiophenoimine and poly (3-hexylthiophene on gold electrode. 1HNMR spectroscopy was used to determine the regioregularity of the polymer composites, whereas Fourier transform infrared spectroscopy and scanning electron microscopy were used to study their structural and morphological properties. Au|G3PPT-co-P3HT in the absence of PHE, exhibited reversible electrochemistry attributable to the oligo (thiophene ‘pendants’ of the dendrimer. PHE produced an increase in the voltammetric signals (anodic currents due to its oxidation on the dendritic material to produce catalytic current, thereby suggesting the suitability of the Au|G3PPT-co-P3HT electrode as a PHE sensor. The electrocatalysis of PHE was made possible by the rigid and planar oligo-P3HT species (formed upon the oxidation of the oligo (thiophene pendants of the star-copolymer, which allowed the efficient capture (binding and detection (electrocatalytic oxidation of PHE molecules.

Irradiation performance of HTGR Biso fertile particles in HFIR experiments HT-17, -18, and -19

International Nuclear Information System (INIS)

Long, E.L. Jr.; Beatty, R.L.; Robbins, J.M.; Kania, M.J.; Eatherly, W.P.

1978-11-01

A series of Biso-coated fertile particles was irradiated in the target facility of the High-Flux Isotope Reactor. The primary objectives of this experiment were to relate the fast-neutron stability of dense propylene-derived pyrocarbons to preferred orientation and to relate irradiation performance to preirradiation characterization values. Coating characterization included x-ray BAF, optical anisotropy, gaseous permeability, small-angle x-ray scattering, and thickness and density determinations. Other objectives were to test Biso-coated large-diameter ThO 2 kernels and coatings derived from propylene diluted with CO 2 rather than argon. Visual examination of the irradiated particles showed that the majority had failed as a result of fast-neutron damage

A density functional theory study of partial oxidation of propylene on Cu2O(0 0 1) and CuO(0 0 1) surfaces

International Nuclear Information System (INIS)

Düzenli, Derya; Atmaca, Deniz Onay; Gezer, Miray Gülbiter; Onal, Isik

2015-01-01

Graphical abstract: - Highlights: • Propylene epoxidation mechanism on Cu 2 O(0 0 1) and CuO(0 0 1) surfaces is investigated using DFT method. • Acrolein is found to be a thermodynamically more favorable product for both surfaces especially over CuO surface. • The more basic property of the surface oxygen increases the probability of acrolein formation over CuO(0 0 1) surface. - Abstract: This work theoretically investigates propylene epoxidation reaction on Cu 2 O(0 0 1) and CuO(0 0 1) surfaces using periodical DFT method to determine the active copper species within the reaction mechanism. The transition states and energy profiles are calculated for the formation of surface intermediates such as oxametallopropylene (OMP) over Cu 2 O(0 0 1) and oxygen bridging (OB) over CuO(0 0 1) and allylic H-stripping reaction (AHS) over both surfaces as well as for formation of products. Propylene oxide (PO) and acetone are obtained through OMP and OB surface intermediates and acrolein generation is observed through allylic H-stripping reaction (AHS). The calculations revealed that the corresponding surface intermediates for epoxidation reaction need to overcome an activation barrier of 13 kcal/mol over CuO surface whereas they occur without an energy barrier over Cu 2 O surface indicating the higher activity of Cu + species. Acrolein is also found to be a thermodynamically more favorable product for both surfaces especially over CuO surface due to the presence of more surface oxygen atoms on which the basicity has been evaluated by the adsorption of sulfur dioxide. This indicates that the lattice oxygen inherent in both surface types does not participate in PO production.

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

International Nuclear Information System (INIS)

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

2015-01-01

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.

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

Energy Technology Data Exchange (ETDEWEB)

Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Haraveen, K.J.S.; Tee, Tiam-Ting [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

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.

Effect of soy sauce on lipid oxidation of irradiated pork patties

Science.gov (United States)

Kim, Hyun-Wook; Hwang, Ko-Eun; Choi, Yun-Sang; Choi, Ji-Hun; Lee, Mi-Ai; Song, Dong-Heon; Kim, Hack-Youn; Lee, Ju-Woon; Kim, Cheon-Jei

2013-09-01

This study was conducted to find out the antioxidant effect of the soy sauce on lipid oxidation of electron beam irradiated pork patties. The pork patties prepared with sodium chloride or soy sauce solution at identical salt concentrations were irradiated at 0 or 5 kGy, and peroxide value, conjugated diene, 2-thiobarbituric acid, and free fatty acid values were evaluated for 10 days (4 °C). The irradiated pork patties treated with soy sauce showed the lowest peroxide value and 2-thiobarbituric acid value at the end of storage compared to those prepared with sodium chloride. The irradiated pork patties formulated with soy sauce and 0.5% ascorbic acid had similar 2-thiobarbituric acid and free fatty acid values compared to those of the non-irradiated pork patties treated with sodium chloride. Our results suggested that the soy sauce can retard the lipid oxidation of irradiated pork patty, and a synergistic effect between soy sauce and ascorbic acid was observed.

A density functional theory study of partial oxidation of propylene on Cu2O(0 0 1) and CuO(0 0 1) surfaces

Science.gov (United States)

Düzenli, Derya; Atmaca, Deniz Onay; Gezer, Miray Gülbiter; Onal, Isik

2015-11-01

This work theoretically investigates propylene epoxidation reaction on Cu2O(0 0 1) and CuO(0 0 1) surfaces using periodical DFT method to determine the active copper species within the reaction mechanism. The transition states and energy profiles are calculated for the formation of surface intermediates such as oxametallopropylene (OMP) over Cu2O(0 0 1) and oxygen bridging (OB) over CuO(0 0 1) and allylic H-stripping reaction (AHS) over both surfaces as well as for formation of products. Propylene oxide (PO) and acetone are obtained through OMP and OB surface intermediates and acrolein generation is observed through allylic H-stripping reaction (AHS). The calculations revealed that the corresponding surface intermediates for epoxidation reaction need to overcome an activation barrier of 13 kcal/mol over CuO surface whereas they occur without an energy barrier over Cu2O surface indicating the higher activity of Cu+ species. Acrolein is also found to be a thermodynamically more favorable product for both surfaces especially over CuO surface due to the presence of more surface oxygen atoms on which the basicity has been evaluated by the adsorption of sulfur dioxide. This indicates that the lattice oxygen inherent in both surface types does not participate in PO production.

Study of Propylene Glycol, Dimethylformamide and Formaldehyde Vapors Sensors Based on MWCNTs/SnO2 Nanocomposites

Directory of Open Access Journals (Sweden)

Zaven Adamyan

2017-06-01

Full Text Available We present results of our research works related to the study of thick-film multiwall carbon nanotube/tin oxide nanocomposite sensors of propylene glycol (PG, dimethylformamide (DMF and formaldehyde (FA vapors derived using hydrothermal synthesis and sol-gel methods. Investigations of response/recovery characteristics in the 50-300 oC operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times, are about 200 and 220 oC, respectively. A sensor response dependence on gas concentration in all cases is linear. The minimal propylene glycol and dimethylformamide gas concentrations at which the perceptible signal was registered by us were 13 ppm and 5 ppm, respectively.

Irradiation effects in superconductor oxides. Effets d'irradiation dans les oxydes supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Rullier-Albenque, F; Konczykowski, M [CEA-Ecole Polytechnique, 91 - Palaiseau (France). Lab. d' Etudes des Solides Irradies

1993-01-01

Several effects of irradiation on the 92 K - oxide superconductor YBa[sub 2]Cu[sub 3]O[sub 7] are reported. Whatever irradiation type, the critical temperature T[sub c] is found to decrease and the resistivity to increase. At sufficiently high damage levels, YBa[sub 2]Cu[sub 3]O[sub 7] is no longer superconducting and even displays a semiconducting-like behaviour. The alterations of superconducting properties are clearly related to oxygen defects - in the CuO[sub 2] planes or CuO chains... but we have shown experimentally that copper defects are also important. Magnetic properties of YBa[sub 2]Cu[sub 3]O[sub 7] in mixed state are also very sensitive to irradiation. By pinning the flux lines, irradiation defects can considerably increase the critical current density j[sub c]. At present, irradiations by highly energetic heavy ions (6 GeV Pb for instance), which produce cylindrical tubes of amorphous material (latent tracks) throughout the whole thickness of the samples, are probably the most efficient way to enhance j[sub c]. (Author). 18 refs., 7 figs.

Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

KAUST Repository

Kelly, Michael J.

2017-06-12

A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

KAUST Repository

Kelly, Michael J.; Barthel, Alexander; Maheu, Clement; Sodpiban, Ounjit; Dega, Frank-Blondel; Vummaleti, Sai V.C.; Abou-Hamad, Edy; Pelletier, Jeremie; Cavallo, Luigi; D'Elia, Valerio; Basset, Jean-Marie

2017-01-01

A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

Color and oxidative stability of nitrite-free cured meat after gamma irradiation

International Nuclear Information System (INIS)

Shahidi, F.; Pegg, R.B.; Shamsuzzaman, K.

1991-01-01

The effects of 5 and 10 kGy irradiation on the color and oxidative stability of meats treated with nitrite or a nitrite-free curing system were investigated. The nitrite-free curing system consisted of the preformed cooked cured-meat pigment, sodium ascorbate and sodium tripolyphosphate with or without sodium acid pyrophosphate. Irradiation had no detrimental effects on the color or flavor of either cured samples. Polyphosphates had a beneficial effect on oxidative stability but had a slight detrimental effect on color stability of irradiated samples

Hofmeister effect on thermo-responsive poly(propylene oxide): Role of polymer molecular weight and concentration.

Science.gov (United States)

Moghaddam, Saeed Zajforoushan; Thormann, Esben

2016-03-01

Although a vast amount of research has been dedicated to investigate the Hofmeister effect on the stability of polymer solutions, a clear understanding of the role of polymer properties in this phenomenon is still missing. Here, the Hofmeister effect of NaCl (destabilizing) and NaSCN (stabilizing) salts on aqueous solutions of poly(propylene oxide) (PPO) is studied. Four different molecular weights of PPO were investigated, to determine how the variation in the polymer coil size affects the Hofmeister effect. The investigation was further conducted for different PPO concentrations, in order to understand the effect of inter-chain interactions on the response to addition of salt. The temperature-driven phase separation of the solutions was monitored by differential scanning calorimetry, which provides the precise value of the phase separation temperature, as well as the enthalpy change accompanied with the transition. It was observed that increasing the molecular weight weakens the effect of the both salts, which is interpreted in terms of a scaling law between the molecular weight and the accessible surface area of the polymers. Increasing the PPO concentration further diminished the NaCl effect, but amplified the NaSCN effect. This difference is attributed to an electrostatic stabilization mechanism in the case of NaSCN. Copyright © 2015 Elsevier Inc. All rights reserved.

Gamma-ray irradiation and post-irradiation at room and elevated temperature response of pMOS dosimeters with thick gate oxides

Directory of Open Access Journals (Sweden)

Pejović Momčilo M.

2011-01-01

Full Text Available Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was estimated from the sub-threshold I-V curves, using the midgap technique. It was shown that fixed oxide traps have a dominant influence on the change in the threshold voltage shift during gamma-ray irradiation and annealing.

Irradiation behavior evaluation of oxide dispersion strengthened ferritic steel cladding tubes irradiated in JOYO

Energy Technology Data Exchange (ETDEWEB)

Yamashita, Shinichiro, E-mail: yamashita.shinichiro@jaea.go.jp; Yano, Yasuhide; Ohtsuka, Satoshi; Yoshitake, Tsunemitsu; Kaito, Takeji; Koyama, Shin-ichi; Tanaka, Kenya

2013-11-15

Irradiation behavior of ODS steel cladding tubes was evaluated for the further progress in understanding of the neutron-irradiation effects on ODS steel. Two types of ODS (9Cr–ODS{sub F}/M, 12Cr–ODS{sub F}) steel cladding tubes with differences in basic compositions and matrix phases were irradiated in JOYO. Post-irradiation examination data concerning hardness, ring tensile property, and microstructure were obtained. Hardness measurement after irradiation showed that there was an apparent irradiation temperature dependence on hardness for 9Cr–ODS{sub F}/M steel whereas no distinct temperature dependence for 12Cr–ODS{sub F} steel. Also, there was no significant change in tensile strengths after irradiation below 923 K, but those above 1023 K up to 6.6 × 10{sup 26} n/m{sup 2} (E > 0.1 MeV) were decreased by about 20%. TEM observations showed that the radiation-induced defect cluster formation during irradiation was suppressed because of high density sink site for defect such as initially-existed dislocation, and precipitate interfaces. In addition, oxide particles were stable up to the maximum doses of this irradiation test.

About morphology in ethylene-propylene(-diene) copolymers-based latexes

NARCIS (Netherlands)

Tillier, D.L.; Meuldijk, J.; Hoehne, G.W.H.; Frederik, P.M.; Regev, O.; Koning, C.E.

2005-01-01

Coatings and engineering plastics often require high impact strength. This property can be achieved with tougheners. For the present paper, core-shell impact modifiers were synthesized using ethylene–propylene copolymers (EPM), ethylene–propylene-diene copolymers (EPDM) or a mixture of both types

Influence of electron beam irradiation on the impact properties of polystyrene/EPDM rubber blends

NARCIS (Netherlands)

Gisbergen, van J.G.M.; Sanden, van der M.C.M.; Haan, de J.W.; Ven, van de L.J.M.; Lemstra, P.J.

1991-01-01

The influence of electron beam (EB) irradiation on the impact properties of compatibilized polystyrene/ethylene-propylene-diene-monomer (PSIEPDM) blends was studied. The change in impact value upon irradiation proved to be strongly dependent on the type of compatibilizer used. Using a

A density functional theory study of partial oxidation of propylene on Cu{sub 2}O(0 0 1) and CuO(0 0 1) surfaces

Energy Technology Data Exchange (ETDEWEB)

Düzenli, Derya [Chemical Engineering Department, Middle East Technical University, 06800 Ankara (Turkey); Mineral Analysis and Technology, General Directorate of Mineral Research and Exploration, 06800 Ankara (Turkey); Atmaca, Deniz Onay; Gezer, Miray Gülbiter [Chemical Engineering Department, Middle East Technical University, 06800 Ankara (Turkey); Onal, Isik, E-mail: ional@metu.edu.tr [Chemical Engineering Department, Middle East Technical University, 06800 Ankara (Turkey)

2015-11-15

Graphical abstract: - Highlights: • Propylene epoxidation mechanism on Cu{sub 2}O(0 0 1) and CuO(0 0 1) surfaces is investigated using DFT method. • Acrolein is found to be a thermodynamically more favorable product for both surfaces especially over CuO surface. • The more basic property of the surface oxygen increases the probability of acrolein formation over CuO(0 0 1) surface. - Abstract: This work theoretically investigates propylene epoxidation reaction on Cu{sub 2}O(0 0 1) and CuO(0 0 1) surfaces using periodical DFT method to determine the active copper species within the reaction mechanism. The transition states and energy profiles are calculated for the formation of surface intermediates such as oxametallopropylene (OMP) over Cu{sub 2}O(0 0 1) and oxygen bridging (OB) over CuO(0 0 1) and allylic H-stripping reaction (AHS) over both surfaces as well as for formation of products. Propylene oxide (PO) and acetone are obtained through OMP and OB surface intermediates and acrolein generation is observed through allylic H-stripping reaction (AHS). The calculations revealed that the corresponding surface intermediates for epoxidation reaction need to overcome an activation barrier of 13 kcal/mol over CuO surface whereas they occur without an energy barrier over Cu{sub 2}O surface indicating the higher activity of Cu{sup +} species. Acrolein is also found to be a thermodynamically more favorable product for both surfaces especially over CuO surface due to the presence of more surface oxygen atoms on which the basicity has been evaluated by the adsorption of sulfur dioxide. This indicates that the lattice oxygen inherent in both surface types does not participate in PO production.

21 CFR 500.50 - Propylene glycol in or on cat food.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409 of...

17O NMR investigation of oxidative degradation in polymers under γ-irradiation

International Nuclear Information System (INIS)

ALAM, TODD M.; CELINA, MATHIAS C.; ASSINK, ROGER A.; CLOUGH, ROGER LEE; GILLEN, KENNETH T.

2000-01-01

The γ-irradiated-oxidation of pentacontane (C 50 H 102 ) and the polymer polyisoprene was investigated as a function of oxidation level using 17 O nuclear magnetic resonance (NMR) spectroscopy. It is demonstrated that by using 17 O labeled O 2 gas during the γ-irradiation process, details about the oxidative degradation mechanisms can be directly obtained from the analysis of the 17 O NMR spectra. Production of carboxylic acids is the primary oxygen-containing functionality during the oxidation of pentacontane, while ethers and alcohols are the dominant oxidation product observed for polyisoprene. The formation of ester species during the oxidation process is very minor for both materials, with water also being produced in significant amounts during the radiolytic oxidation of polyisoprene. The ability to focus on the oxidative component of the degradation process using 17 O NMR spectroscopy demonstrates the selectivity of this technique over more conventional approaches

Lactosylated poly(ethylene oxide)-poly(propylene oxide) block copolymers for potential active targeting: synthesis and physicochemical and self-aggregation characterization

Energy Technology Data Exchange (ETDEWEB)

Cuestas, Maria L.; Glisoni, Romina J. [University of Buenos Aires, Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina); Mathet, Veronica L. [National Science Research Council (CONICET) (Argentina); Sosnik, Alejandro, E-mail: alesosnik@gmail.com [University of Buenos Aires, The Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina)

2013-01-15

Aiming to develop polymeric self-assembly nanocarriers with potential applications in active drug targeting to the liver, linear and branched poly(ethylene oxide)-poly(propylene oxide) amphiphiles were conjugated to lactobionic acid (LA), a disaccharide of galactose and gluconic acid, by the conventional Steglich esterification reaction. The conjugation was confirmed by ATR/FT-IR, {sup 1}H-NMR, and {sup 13}C-NMR spectroscopy. Elemental analysis and MALDI-TOF mass spectrometry were employed to elucidate the conjugation extent and the final molecular weight, respectively. The critical micellar concentration (CMC), the size and size distribution and zeta potential of the pristine and modified polymeric micelles under different conditions of pH and temperature were characterized by dynamic light scattering (DLS). Conjugation with LA favored the micellization process, leading to a decrease of the CMC with respect to the pristine counterpart, this phenomenon being independent of the pH and the temperature. At 37 Degree-Sign C, micelles made of pristine copolymers showed a monomodal size distribution between 12.8 and 24.4 nm. Conversely, LA-conjugated micelles showed a bimodal size pattern that comprised a main fraction of relatively small size (11.6-22.2 nm) and a second one with remarkably larger sizes of up to 941.4 nm. The former corresponded to single micelles, while the latter would indicate a secondary aggregation phenomenon. The spherical morphology of LA-micelles was visualized by transmission electron microscopy (TEM). Finally, to assess the ability of the LA-conjugated micelles to interact with lectin-like receptors, samples were incubated with concanavalin A at 37 Degree-Sign C and the size and size distribution were monitored by DLS. Findings indicated that regardless of the relatively weak affinity of this vegetal lectin for galactose, micelles underwent agglutination probably through the interaction of a secondary site in the lectin with the gluconic acid

Quantitative measurements of oxidative stress in mouse skin induced by X-ray irradiation

International Nuclear Information System (INIS)

Chi, Cuiping; Tanaka, Ryoko; Okuda, Yohei; Ikota, Nobuo; Ozawa, Toshihiko; Anzai, Kazunori; Yamamoto, Haruhiko; Urano, Shiro

2005-01-01

To find efficient methods to evaluate oxidative stress in mouse skin caused by X-ray irradiation, several markers and methodologies were examined. Hairless mice were irradiated with 50 Gy X-rays and skin homogenates or skin strips were prepared. Lipid peroxidation was measured using the skin homogenate as the level of thiobarbituric acid reactive substances. The level of lipid peroxidation increased with time after irradiation and was twice that of the control at 78 h. Electron spin resonance (ESR) spectra of skin strips showed a clear signal for the ascorbyl radical, which increased with time after irradiation in a manner similar to that of lipid peroxidation. To measure levels of glutathione (GSH) and its oxidized forms (GSSG) simultaneously, two high performance liquid chromatography (HPLC) methods, sample derivatization with 1-fluoro-2,4-dinitrobenzene and detection with a UV detector (method A) and no derivatization and detection with an electrochemical detector (method B), were compared and the latter was found to be better. No significant change was observed within 24 h after irradiation in the levels of GSH and GSSG measured by method B. The GSH/GSSG ratio may be a less sensitive parameter for the evaluation of acute oxidative stress caused by X-ray irradiation in the skin. Monitoring the ascorbyl radical seems to be a good way to evaluate oxidative stress in skin in vivo. (author)

Poly(ethylene oxide monomethyl ether)- block-poly(propylene succinate) Nanoparticles: Synthesis and Characterization, Enzymatic and Cellular Degradation, Micellar Solubilization of Paclitaxel, and in Vitro and in Vivo Evaluation.

Science.gov (United States)

Jäger, Alessandro; Jäger, Eliézer; Syrová, Zdeňka; Mazel, Tomas; Kováčik, Lubomír; Raška, Ivan; Höcherl, Anita; Kučka, Jan; Konefal, Rafal; Humajova, Jana; Poučková, Pavla; Štěpánek, Petr; Hrubý, Martin

2018-04-11

Polyester-based nanostructures are widely studied as drug-delivery systems due to their biocompatibility and biodegradability. They are already used in the clinic. In this work, we describe a new and simple biodegradable and biocompatible system as the Food and Drug Administration approved polyesters (poly-ε-caprolactone, polylactic acid, and poly(lactic- co-glycolic acid)) for the delivery of the anticancer drug paclitaxel (PTX) as a model drug. A hydrophobic polyester, poly(propylene succinate) (PPS), was prepared from a nontoxic alcohol (propylene glycol) and monomer from the Krebs's cycle (succinic acid) in two steps via esterification and melt polycondensation. Furthermore, their amphiphilic block copolyester, poly(ethylene oxide monomethyl ether)- block-poly(propylene succinate) (mPEO- b-PPS), was prepared by three steps via esterification followed by melt polycondensation and the addition of mPEO to the PPS macromolecules. Analysis of the in vitro cellular behavior of the prepared nanoparticle carriers (NPs) (enzymatic degradation, uptake, localization, and fluorescence resonance energy-transfer pair degradation studies) was performed by fluorescence studies. PTX was loaded to the NPs of variable sizes (30, 70, and 150 nm), and their in vitro release was evaluated in different cell models and compared with commercial PTX formulations. The mPEO- b-PPS copolymer analysis displays glass transition temperature hydrolysis during transport in bloodstream, and simultaneous enzymatic degradability after uptake into the cells. The detailed cytotoxicity in vitro and in vivo tumor efficacy studies have shown the superior efficacy of the NPs compared with PTX and PTX commercial formulations.

Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

KAUST Repository

Pan, Yichang

2012-02-01

The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed excellent separation performances for a wide range of propylene/propane mixtures. The membrane showed a permeability of propylene up to 200. barrers and a propylene to propane separation factor up to 50 at optimal separation conditions, well surpassing the "upper-bound trade-off" lines of existing polymer and carbon membranes. The experimental data also showed that the membranes had excellent reproducibility, long-term stability and thermal stability. © 2011 Elsevier B.V.

A study of the ion-molecule reaction in a microwave plasma of propylene

International Nuclear Information System (INIS)

Carmi, U.

1980-07-01

Microwave plasma of propylene and of argon-propylene mixture were sampled by a quadrupole mass-spectrometer. The composition of the plasma was investigated as a function of external parameters such as pressure, initial concentration of gases, microwave power and sampling position. Three main paths were determined for the pyrolysis and polymerization of propylene, that constitute the rate determining step. Rate constants were determined for the various reactions between propylene and the intermediates. An overall rate constant for the disappearance of propylene was determined. This constant was found to be dependent on the initial gas concentration and on plasma pressure

UV irradiation-induced methionine oxidation in human skin keratins: Mass spectrometry-based non-invasive proteomic analysis.

Science.gov (United States)

Lee, Seon Hwa; Matsushima, Keita; Miyamoto, Kohei; Oe, Tomoyuki

2016-02-05

Ultraviolet (UV) radiation is the major environmental factor that causes oxidative skin damage. Keratins are the main constituents of human skin and have been identified as oxidative target proteins. We have recently developed a mass spectrometry (MS)-based non-invasive proteomic methodology to screen oxidative modifications in human skin keratins. Using this methodology, UV effects on methionine (Met) oxidation in human skin keratins were investigated. The initial screening revealed that Met(259), Met(262), and Met(296) in K1 keratin were the most susceptible oxidation sites upon UVA (or UVB) irradiation of human tape-stripped skin. Subsequent liquid chromatography/electrospray ionization-MS and tandem MS analyses confirmed amino acid sequences and oxidation sites of tryptic peptides D(290)VDGAYMTK(298) (P1) and N(258)MQDMVEDYR(267) (P2). The relative oxidation levels of P1 and P2 increased in a time-dependent manner upon UVA irradiation. Butylated hydroxytoluene was the most effective antioxidant for artifactual oxidation of Met residues. The relative oxidation levels of P1 and P2 after UVA irradiation for 48 h corresponded to treatment with 100mM hydrogen peroxide for 15 min. In addition, Met(259) was oxidized by only UVA irradiation. The Met sites identified in conjunction with the current proteomic methodology can be used to evaluate skin damage under various conditions of oxidative stress. We demonstrated that the relative Met oxidation levels in keratins directly reflected UV-induced damages to human tape-stripped skin. Human skin proteins isolated by tape stripping were analyzed by MS-based non-invasive proteomic methodology. Met(259), Met(262), and Met(296) in K1 keratin were the most susceptible oxidation sites upon UV irradiation. Met(259) was oxidized by only UVA irradiation. Quantitative LC/ESI-SRM/MS analyses confirmed a time-dependent increase in the relative oxidation of target peptides (P1 and P2) containing these Met residues, upon UVA irradiation

Quercetin oxidation by horseradish peroxidase: The effect of UV-B irradiation

Directory of Open Access Journals (Sweden)

Savić Saša R.

2013-01-01

Full Text Available Horseradish peroxidase (HRP, a highly-investigated member of the peroxidase family has been known, among many other biological activities, to catalyze the oxidation of flavonoids and phenolic substrates overall, including quercetin. On the other hand, quercetin is very well known for its antioxidant activities, which in the case of UV external radiation is exibited partly in a preventive manner since it is an excellent UV-absorber. Therefore the aim of this investigation is to study quercetin oxidation by HRP in phosphate buffer under the conditions of UV-stress, i.e. continuous, prolonged UV-B irradiation. The results show that while UV-B irradiation affects the activity of HRP, and the overal rate of quercetin oxidation by HRP, it probably has very little effect on it for longer UV-B-irradiation periods (>30 min. [Acknowledgements. This work was supported by the Ministry of Education and Science of the Republic of Serbia under Project No.TR-34012 and OI-172044

Schisandrin B protects against solar irradiation-induced oxidative injury in BJ human fibroblasts.

Science.gov (United States)

Chiu, Po Yee; Lam, Philip Y; Yan, Chung Wai; Ko, Kam Ming

2011-06-01

The effects of schisandrin B (Sch B) and its analogs on solar irradiation-induced oxidative injury were examined in BJ human fibroblasts. Sch B and schisandrin C (Sch C) increased cellular reduced glutathione (GSH) level and protected against solar irradiation-induced oxidative injury. The photoprotection was paralleled by decreases in the elastases-type protease activity and matrix-metalloproteinases-1 expression in solar-irradiated fibroblasts. The cytochrome P-450-mediated metabolism of Sch B or Sch C caused ROS production. The results suggest that by virtue of its pro-oxidant action and the subsequent glutathione antioxidant response, Sch B or Sch C may offer the prospect of preventing skin photo-aging. Copyright © 2011 Elsevier B.V. All rights reserved.

Alternating copolymerization of propylene oxide with biorenewable terpene-based cyclic anhydrides: a sustainable route to aliphatic polyesters with high glass transition temperatures.

Science.gov (United States)

Van Zee, Nathan J; Coates, Geoffrey W

2015-02-23

The alternating copolymerization of propylene oxide with terpene-based cyclic anhydrides catalyzed by chromium, cobalt, and aluminum salen complexes is reported. The use of the Diels-Alder adduct of α-terpinene and maleic anhydride as the cyclic anhydride comonomer results in amorphous polyesters that exhibit glass transition temperatures (Tg ) of up to 109 °C. The polymerization conditions and choice of catalyst have a dramatic impact on the molecular weight distribution, the relative stereochemistry of the diester units along the polymer chain, and ultimately the Tg of the resulting polymer. The aluminum salen complex exhibits exceptional selectivity for copolymerization without transesterification or epimerization side reactions. The resulting polyesters are highly alternating and have high molecular weights and narrow polydispersities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biosynthesis of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by bacterial community from propylene oxide saponification wastewater residual sludge.

Science.gov (United States)

Wang, Yiwei; Zhu, Ying; Gu, Pengfei; Li, Yumei; Fan, Xiangyu; Song, Dongxue; Ji, Yan; Li, Qiang

2017-05-01

The saponification wastewater from the process of propylene oxide (PO) production is contaminated with high chemical oxygen demand (COD) and chlorine contents. Although the activated sludge process could treat the PO saponification wastewater effectively, the residual sludge was difficult to be disposed properly. In this research, microbes in PO saponification wastewater residual sludge were acclimated to produce poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from volatile fatty acids. Through Miseq Illumina highthroughput sequencing, the bacterial community discrepancy between the original and the acclimated sludge samples were analyzed. The proportions of Bacillus, Acinetobacter, Brevundimonas and Pseudomonas, the potential PHBV-producers in the residual sludge, were all obviously increased. In the batch fermentation, the production of PHBV could achieve 4.262g/L at 300min, with the content increased from 0.04% to 23.67% of mixed liquor suspended solid (MLSS) in the acclimated sludge, and the COD of the PO saponification wastewater was also decreased in the fermentation. This work would provide an effective solution for the utilization of PO saponification wastewater residual sludge. Copyright © 2017 Elsevier B.V. All rights reserved.

Lipid and cholesterol oxidation, color changes, and volatile compounds production in irradiated raw pork batters with different fat content

International Nuclear Information System (INIS)

Jo, Cheo Run; Byun, Myung Woo

2000-01-01

An emulsion-type product was prepared to determine the effect of irradiation on lipid and cholesterol oxidation, color change, and volatile production in raw pork with different fat content. Lipid oxidation increased with an increase in fat content or irradiation dose. Irradiated batters had higher cholesterol oxides than did non-irradiated batters, and the major cholesterol oxides formed in irradiated pork batters were 7α- and 7β- hydroxycholesterol. Hunter color a- and b-values of raw pork batters were decreased by irradiation regardless of fat content. Irradiation significantly increased the amount of volatile compounds. Although lipid oxidation of high fat products (10 and 15% fat) was higher than that of low fat products (4%), high fat products did not always produce greater amount of volatile compounds in raw pork batters. In summary, irradiation increased lipid and cholesterol oxidation, and volatile compounds production, and had detrimental effects on the color of raw pork batter under aerobic conditions

Blue light irradiation-induced oxidative stress in vivo via ROS generation in rat gingival tissue.

Science.gov (United States)

Yoshida, Ayaka; Shiotsu-Ogura, Yukako; Wada-Takahashi, Satoko; Takahashi, Shun-suke; Toyama, Toshizo; Yoshino, Fumihiko

2015-10-01

It has been reported that oxidative stress with reactive oxygen species (ROS) generation is induced by blue light irradiation to a living body. Only limited research has been reported in dental field on the dangers of blue light, mostly focusing on cytotoxicity associated with heat injury of dental pulp. We thus performed an in vivo study on oral tissue exposed to blue light. ROS generated upon blue light irradiation of flavin adenine dinucleotide were measured by electron spin resonance spectroscopy. After blue light irradiation, the palatal gingiva of Wistar rats were isolated. Collected samples were subjected to biochemical analysis of lipid peroxidation and glutathione. Singlet oxygen was generated by blue light irradiation, but was significantly quenched in an N-acetyl-L-cysteine (NAC) concentration-dependent manner. Blue light significantly accelerated oxidative stress and increased the oxidized glutathione levels in gingival tissue. These effects were also inhibited by NAC pre-administration. The results suggest that blue light irradiation at clinical levels of tooth bleaching treatment may enhance lipid peroxidation by the induction of oxidative stress and the consumption of a significant amount of intracellular glutathione. In addition, NAC might be an effective supplement for the protection of oral tissues against blue light irradiation-induced oxidative damage. Copyright © 2015 Elsevier B.V. All rights reserved.

Technological parameters and oxidative stability of irradiated wheat and corn flour

International Nuclear Information System (INIS)

Silva, Roberta Claro da

2003-01-01

Cereals are susceptible to the attack of insects and microorganisms development during storage. Researches have demonstrated the viability of the use of the irradiation technology for the preservation and reduction of these losses. The objective of this work was to evaluate the effect of different irradiation doses (0; 3; 4,5 and 6 kGy) on wheat and corn flour oxidative stability and technological quality. Physicochemical and sensory analyses were performed on the flours. The technological parameters evaluated on the wheat flour were farinogram, alveogram, falling number, and a baking experiment. The packed samples were irradiated in a commercial irradiator and stored under ambient conditions. The oxidative quality of both flours was not affected in any of the treatments, within the commercial shelf life period guaranteed by the manufacturers for non irradiated products. However, flours acid value was the analytical parameter that reflected the irradiation effect. The higher flour initial acid values were the larger the increments with storage. The 4.5 and 6 kGy treatments ha a negative effect on the technological quality of the wheat flour. The irradiated flours had their viscoelastic properties affected the higher the irradiation dose, the stronger the effect. None of the treatments affected the sensorial quality of the samples, although a metallic odor was perceived by some tasters. (author)

Characteristic of Irradiation Result Film of Poly-Propylene-Co-Ethylene/Poly-ε-Caprolactone and Poly-Propylene Grafted Maleic Anhydrate Blend

International Nuclear Information System (INIS)

Nikham

2004-01-01

The effect of gamma rays irradiation to film of melt-blending polypropylene-co-ethylene (CPP) and poly-ε-caprolactone (PCL) with polypropylene grafted maleic anhydride (PP-g-MAH) blend as compatibilizer has been studied. The objective of the research is to prepare the biodegradable polyblend. The composition blend of CPP/PCL with 0, 10, 15, 20 wt % PP-g-MAH i.e. 100/0, 75/25, 50/50, 25/75 and 0/100 were irradiated by using gamma rays 60 Co with activity 420 kCi at doses; 0, 50, 100, 150, 200 kGy, at dose rate 8.2 kGy/hrs and temperature 90 o C. The elongation at break, tensile strength, gel fraction, enzymatic degradation and heat resistance were evaluated. The results showed that the compatibility of PP-g-MAH to reach good enough polyblend is 20 % weight. Elongation at break film of CPP/PCL 50/50 blend which irradiated at dose 200 kGy decreased, whereas the tensile strength increased. Gel fraction and heat resistance of the film irradiated increased. Enzyme of lipase AK can degraded either without irradiated or irradiated film. Thus quality of the polyblend can be called as biodegradable plastic material. (author)

Physical properties of beryllium oxide - Irradiation effects

International Nuclear Information System (INIS)

Elston, J.; Caillat, R.

1958-01-01

This work has been carried out in view of determining several physical properties of hot-pressed beryllium oxide under various conditions and the change of these properties after irradiation. Special attention has been paid on to the measurement of the thermal conductivity coefficient and thermal diffusivity coefficient. Several designs for the measurement of the thermal conductivity coefficient have been achieved. They permit its determination between 50 and 300 deg. C, between 400 and 800 deg. C. Some measurements have been made above 1000 deg. C. In order to measure the thermal diffusivity coefficient, we heat a perfectly flat surface of a sample in such a way that the heat flux is modulated (amplitude and frequency being adjustable). The thermal diffusivity coefficient is deduced from the variations of temperature observed on several spots. Tensile strength; compressive strength; expansion coefficient; sound velocity and crystal parameters have been also measured. Some of the measurements have been carried out after neutron irradiation. Some data have been obtained on the change of the properties of beryllium oxide depending on the integrated neutron flux. (author) [fr

Structural changes in graphene oxide thin film by electron-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Chetna, E-mail: tchetna91@gmail.com [Materials Science Group, Inter University Accelerator Centre, New Delhi 67 (India); Lakshmi, G.B.V.S.; Kumar, Sunil; Tripathi, Ambuj [Materials Science Group, Inter University Accelerator Centre, New Delhi 67 (India); Avasthi, D.K. [Amity University, Noida 201313, Uttar Pradesh (India)

2016-07-15

Although we have a whole class of 2D materials, graphene has drawn much attention for its excellent electronic, optical, thermal and mechanical properties. Recent researches have shown its large scale production by the reduction of graphene oxide either thermally, chemically or electrochemically. Although the structure of graphene oxide is inhomogeneous and hence complicated due to the presence of organic moieties e.g. epoxy, carboxylic acid, hydroxyl groups etc., its properties can be tuned by reduction according to desired application. The aim of this work is to synthesize continuous thin film of graphene oxide using commercially available graphene oxide solution and to study its reduction by 25 keV electron beam irradiation at fluences varying from 2 × 10{sup 11} to 2 × 10{sup 13} e{sup −}/cm{sup 2}. Our studies using X-ray diffraction, Raman microscopy and UV–Vis spectroscopy showed that electron-beam irradiation is an effective tool for reduction of graphene oxide and for tuning its band gap.

Effects of gamma irradiation in graphene/poly (ethylene oxide) nanocomposites

International Nuclear Information System (INIS)

Braz, Elton P.; Goncalves, Natercia Antunes; Araujo, Patricia L.B.; Araujo, Elmo S.

2013-01-01

Nanotechnology is the understanding and control of matter in dimensions between 1 and 100nm. In such small matter portions, improved or even new properties may arise, as a direct consequence of reduced size. Thus, the development of multifunctional nanomaterials is nowadays one of the main goals of the materials research field. In this context, we produced graphene sheets through ultrasound exfoliation of graphite oxide, followed by chemical reduction. Composite nanofibers of these graphene sheets with biocompatible polymer poly (ethylene oxide) (PEO) were obtained by electrospinning technique, and irradiated up to 75kGy dose to assess the effects of gamma irradiation in the molecular structure of these composite nanomaterial. Our findings showed that PEO is quite resistant to radiation damage and that the incorporation of graphene oxide has no significant influence on its radiostability. (author)

Tissue Engineering Bionanocomposites Based on Poly(propylene fumarate

Directory of Open Access Journals (Sweden)

Ana M. Diez-Pascual

2017-06-01

Full Text Available Poly(propylene fumarate (PPF is a linear and unsaturated copolyester based on fumaric acid that has been widely investigated for tissue engineering applications in recent years due to its tailorable mechanical performance, adjustable biodegradability and exceptional biocompatibility. In order to improve its mechanical properties and spread its range of practical applications, novel approaches need to be developed such as the incorporation of fillers or polymer blending. Thus, PPF-based bionanocomposites reinforced with different amounts of single-walled carbon nanotubes (SWCNT, multi-walled carbon nanotubes (MWCNT, graphene oxide nanoribbons (GONR, graphite oxide nanoplatelets (GONP, polyethylene glycol-functionalized graphene oxide (PEG-GO, polyethylene glycol-grafted boron nitride nanotubes (PEG-g-BNNTs and hydroxyapatite (HA nanoparticles were synthesized via sonication and thermal curing, and their morphology, biodegradability, cytotoxicity, thermal, rheological, mechanical and antibacterial properties were investigated. An increase in the level of hydrophilicity, biodegradation rate, stiffness and strength was found upon increasing nanofiller loading. The nanocomposites retained enough rigidity and strength under physiological conditions to provide effective support for bone tissue formation, showed antibacterial activity against Gram-positive and Gram-negative bacteria, and did not induce toxicity on human dermal fibroblasts. These novel biomaterials demonstrate great potential to be used for bone tissue engineering applications.

Preparation and Properties of Poly (vinylidene fluoride)/poly(dimethylsiloxane) graft (poly(propylene oxide)-block-poly(ethylene oxide)) blend porous separators and corresponding electrolytes

International Nuclear Information System (INIS)

Li, Hao; Zhang, Hong; Liang, Zhi-Ying; Chen, Yue-Ming; Zhu, Bao-Ku; Zhu, Li-Ping

2014-01-01

Highlights: •This work aims exploring microporous PVDF separators for lithium ion batteries. •Comb structure polymer PDMS-g-(PPO-PEO) was used in PVDF blend separators. •The influence of polyether side chains on interfacial resistance was studied. -- Abstract: This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene fluoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5 × 10 −3 S/cm at room temperature, while the electrochemical stability was up to 4.7 V (vs. Li/Li + ). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5 C

Tuning surface properties of graphene oxide quantum dots by gamma-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Lu, Shunkai; Liao, Fan, E-mail: fliao@suda.edu.cn; Wang, Tao; Zhu, Lili; Shao, Mingwang, E-mail: mwshao@suda.edu.cn

2016-07-15

Gamma-ray irradiation was employed to tune surface properties of graphene oxide quantum dots (GOQDs), such as functional groups and defect density. The GOQDs were first oxidized under γ-ray irradiation with doses ranging from 0 to 200 kGy, and then reduced under larger irradiation doses from 200 to 400 kGy. In other words, both the defect density and the number of surface functional groups increased first and then decreased along with the increasing irradiation dose. This process was confirmed with UV–visible absorption, X-ray photoelectron spectroscopy, Raman spectra and Fourier transform infrared spectra. In order to estimate their π-conjugated content, the GOQDs were served to quench the fluorescence of Rhodamine 6 G. The results showed that there existed a positive relationship between the π-conjugated content and the static quenching coefficient V{sub q}Na, which might have a potential value. - Highlights: • The conjugate extent and hydrophily of GOQDs decreased along with irradiation dose. • Gamma-ray irradiation weakens the quenching effect of GOQDs. • Quenching mechanism is a combination of dynamic and static quenching.

Study of the stability of the nanometer-sized oxides dispersed in ODS steels under ion irradiations

International Nuclear Information System (INIS)

Lescoat, M.-L.

2012-01-01

Oxide Dispersion Strengthened (ODS) Ferritic-Martensitic (FM) alloys are expected to play an important role as cladding materials in Generation IV sodium fast reactors operating in extreme temperature (400-500 C) and irradiation conditions (up to 200 dpa). Since nano-oxides give ODS steels their high temperature strength, the stability of these particles is an important issue. The present study evaluates the radiation response of nano-oxides by the use of in-situ and ex-situ ion irradiations performed on both Fe18Cr1W0,4Ti +0,3 Y 2 O 3 and Fe18Cr1W0,4Ti + 0.3 MgO ODS steels. In particular, the results showed that Y-Ti-O nano-oxides are quite stable under very high irradiation dose, namely 219 dpa at 500 C, and that the oxide interfacial structures are likely playing an important role on the behavior under irradiation (oxide stability and point defect recombination. (author) [fr

Packaging and irradiation effects on lipid oxidation and volatiles in pork patties

International Nuclear Information System (INIS)

Ahn, D.U.; Olson, D.G.; Lee, J.I.; Jo, C.; Wu, C.; Chen, X.

1998-01-01

Raw-meat patties were prepared from three pork muscles, irradiated in different packaging environments, and stored for 0 or 3 days before cooking. Lipid oxidation by-products were formed in the raw meat during storage and the baseline lipid oxidation data of raw meat was used to measure the progression of lipid oxidation after cooking. Thiobarbituric acid-reactive substances (TBARS) and volatiles data indicated that preventing oxygen exposure after cooking was more important for cooked meat quality than packaging, irradiation, or storage conditions of raw meat. Propanal, pentanal, hexanal, 1-pentanol, and total volatiles correlated highly (P 0.01) with TBARS values of cooked meat. Hexanal and total volatiles represented the lipid oxidation status better than any other individual volatile components

Stability under irradiation of a fine dispersion of oxides in a ferritic matrix; Stabilite sous irradiation de particules d'oxydes finement dispersees dans des alliages ferritiques

Energy Technology Data Exchange (ETDEWEB)

Monnet, I

1999-07-01

Oxide dispersion strengthened (ODS) ferritic-martensitic steels are being considered for high temperature, high fluence nuclear applications, like fuel pin cladding in Fast Breeder Reactors. ODS alloys offer improved out of pile strength characteristics at temperature above 550 deg.C and ferritic-martensitic matrix is highly swelling resistant. A clad in an ODS ferritic steel, call DY (Fe-13Cr-1,5Mo+TiO{sub 2}+Y{sub 2}O{sub 3}) has been irradiated in the experimental reactor Phenix. Under irradiation oxide dissolution occurs. Microstructural observations indicated that oxide evolution is correlated with the dose and consist in four phenomena: the interfaces of oxide particles with the matrix become irregular, the uniform distribution of the finest oxide (< 20 nm) disappear, the modification of oxide composition, and a halo of fine oxides appear around the larger oxides. The use of such a material requires a study of oxide stability under irradiation, since the oxide particles provide the desired mechanical properties. The study is based on two types of alloys, the DY and four ferritic steels Fe-9Cr-1Mo reinforced by Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3}, MgO or MgAl{sub 2}O{sub 4}. These materials were irradiated with charged particles in order to gain a better understanding of the mechanisms of dissolution. Irradiation with 1 MeV Helium does not induce any modification, neither in the chemical modification of the particles nor in their spatial and size distribution. Since most of the energy of helium ions is lost by inelastic interaction, this result proves that this kind of interaction does not induce oxide dissolution. Irradiation with 1 MeV or 1.2 MeV electrons leads to a significant dissolution with a radius decrease proportional to the dose. These experiments prove that oxide dissolution can be induced by Frenkel pairs alone, provided that metallic atoms are displaced. The comparison between irradiation with ions (displacements cascades) and electrons (Frenkel

Designing Multifunctionality into Single Phase and Multiphase Metal-Oxide-Selective Propylene Ammoxidation Catalysts

Directory of Open Access Journals (Sweden)

James F. Brazdil

2018-03-01

Full Text Available Multifunctionality is the hallmark of most modern commercial heterogeneous catalyst systems in use today, including those used for the selective ammoxidation of propylene to acrylonitrile. It is the quintessential principle underlying commercial catalyst design efforts since petrochemical process development is invariably driven by the need to reduce manufacturing costs. This is in large part achieved through new and improved catalysts that increase selectivity and productivity. In addition, the future feedstocks for chemical processes will be invariably more refractory than those currently in use (e.g., replacing alkenes with alkanes or using CO2, thus requiring a disparate combination of chemical functions in order to effect multiple chemical transformations with the fewest separate process steps. This review summarizes the key chemical phenomena behind achieving the successful integration of multiple functions into a mixed-metal-oxide-selective ammoxidation catalyst. An experiential and functional catalyst design model is presented that consists of one or both of the following components: (1 a mixed-metal-oxide–solid solution where the individual metal components serve separate and necessary functions in the reaction mechanism through their atomic level interaction in the context of a single crystallographic structure; (2 the required elemental components and their catalytic function existing in separate phases, where these phases are able to interact for the purposes of electron and lattice oxygen transfer through the formation of a structurally coherent interface (i.e., epitaxy between the separate crystal structures. Examples are provided from the literature and explained in the context of this catalyst design model. The extension of the model concepts to the design of heterogeneous catalysts in general is also discussed.

Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure

International Nuclear Information System (INIS)

Baranwal, R.; Burke, M.G.

2003-01-01

Oxide dispersion strengthened (ODS) molybdenum has been characterized using transmission electron microscopy (TEM) to determine the effects of irradiation on material microstructure. This work describes the results-to-date from TEM characterization of unirradiated and irradiated ODS molybdenum. The general microstructure of the unirradiated material consists of fine molybdenum grains (< 5 (micro)m average grain size) with numerous low angle boundaries and isolated dislocation networks. 'Ribbon'-like lanthanum oxides are aligned along the working direction of the product form and are frequently associated with grain boundaries, serving to inhibit grain boundary and dislocation movement. In addition to the 'ribbons', discrete lanthanum oxide particles have also been detected. After irradiation, the material is characterized by the presence of nonuniformly distributed large (∼ 20 to 100 nm in diameter), multi-faceted voids, while the molybdenum grain size and oxide morphology appear to be unaffected by irradiation

Radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene in flow system, (9)

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Ito, Masayuki; Okamoto, Jiro; Machi, Sueo.

1982-02-01

Seeded copolymerization of tetrafluoroethylene with propylene by radiation was carried out in a flow apparatus with pipe reactor at a pressure of 30 kg/cm 2 , a temperature of 40 0 C, a dose rate of 4.9 x 10 5 rad/h, and at various monomer compositions. Polymer concentration in latex increases linearly at propylene fraction of 0.25 and accelerately at the fraction below 0.1 with reaction time. The polymerization rates are 36, 60, 57, and 46 g/h.l-H 2 O at propylene fractions of 0.01, 0.05, 0.1, and 0.25, respectively. Fluorine content of the polymer obtained at the end of polymerization is 53.8 wt% at propylene fractions of 0.25 and 0.1, and is 56.5 wt% at the fraction of 0.01. For the insoluble polymer in tetrahydrofuran produced at the fraction of 0.01, the fluorine content is 61.3 wt%. This indicates that monomer unit ratio of tetrafluoroethylene and propylene is 1.8/l. In the polymerization at a region of high tetrafluoroethylene content in monomer gas, it was elucidated that alternative arrangement of copolymer being characteristic in this system is broken down to produce tetrafluoroethylene rich polymer, and polymerization rate is reduced. This is explained by that addition of propylene monomer to tetrafluoroethylene polymer radical becomes rate-determining step due to the extremely poor propylene concentration in polymer particles. (author)

Light water reactor mixed-oxide fuel irradiation experiment

International Nuclear Information System (INIS)

Hodge, S.A.; Cowell, B.S.; Chang, G.S.; Ryskamp, J.M.

1998-01-01

The United States Department of Energy Office of Fissile Materials Disposition is sponsoring and Oak Ridge National Laboratory (ORNL) is leading an irradiation experiment to test mixed uranium-plutonium oxide (MOX) fuel made from weapons-grade (WG) plutonium. In this multiyear program, sealed capsules containing MOX fuel pellets fabricated at Los Alamos National Laboratory (LANL) are being irradiated in the Advanced Test Reactor (ATR) at the Idaho National Engineering and Environmental Laboratory (INEEL). The planned experiments will investigate the utilization of dry-processed plutonium, the effects of WG plutonium isotopics on MOX performance, and any material interactions of gallium with Zircaloy cladding

Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

Energy Technology Data Exchange (ETDEWEB)

Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

1984-11-01

The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood.

Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

International Nuclear Information System (INIS)

Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

1984-01-01

The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood

Low-temperature formation of high-quality gate oxide by ultraviolet irradiation on spin-on-glass

International Nuclear Information System (INIS)

Usuda, R.; Uchida, K.; Nozaki, S.

2015-01-01

Although a UV cure was found to effectively convert a perhydropolysilazane (PHPS) spin-on-glass film into a dense SiO x film at low temperature, the electrical characteristics were never reported in order to recommend the use of PHPS as a gate-oxide material that can be formed at low temperature. We have formed a high-quality gate oxide by UV irradiation on the PHPS film, and obtained an interface midgap trap density of 3.4 × 10 11  cm −2 eV −1 by the UV wet oxidation and UV post-metallization annealing (PMA), at a temperature as low as 160 °C. In contrast to the UV irradiation using short-wavelength UV light, which is well known to enhance oxidation by the production of the excited states of oxygen, the UV irradiation was carried out using longer-wavelength UV light from a metal halide lamp. The UV irradiation during the wet oxidation of the PHPS film generates electron-hole pairs. The electrons ionize the H 2 O molecules and facilitate dissociation of the molecules into H and OH − . The OH − ions are highly reactive with Si and improve the stoichiometry of the oxide. The UV irradiation during the PMA excites the electrons from the accumulation layer, and the built-in electric field makes the electron injection into the oxide much easier. The electrons injected into the oxide recombine with the trapped holes, which have caused a large negative flat band voltage shift after the UV wet oxidation, and also ionize the H 2 O molecules. The ionization results in the electron stimulated dissociation of H 2 O molecules and the decreased interface trap density

Low-temperature formation of high-quality gate oxide by ultraviolet irradiation on spin-on-glass

Energy Technology Data Exchange (ETDEWEB)

Usuda, R.; Uchida, K.; Nozaki, S., E-mail: nozaki@ee.uec.ac.jp [Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, Tokyo 182-1515 (Japan)

2015-11-02

Although a UV cure was found to effectively convert a perhydropolysilazane (PHPS) spin-on-glass film into a dense SiO{sub x} film at low temperature, the electrical characteristics were never reported in order to recommend the use of PHPS as a gate-oxide material that can be formed at low temperature. We have formed a high-quality gate oxide by UV irradiation on the PHPS film, and obtained an interface midgap trap density of 3.4 × 10{sup 11 }cm{sup −2} eV{sup −1} by the UV wet oxidation and UV post-metallization annealing (PMA), at a temperature as low as 160 °C. In contrast to the UV irradiation using short-wavelength UV light, which is well known to enhance oxidation by the production of the excited states of oxygen, the UV irradiation was carried out using longer-wavelength UV light from a metal halide lamp. The UV irradiation during the wet oxidation of the PHPS film generates electron-hole pairs. The electrons ionize the H{sub 2}O molecules and facilitate dissociation of the molecules into H and OH{sup −}. The OH{sup −} ions are highly reactive with Si and improve the stoichiometry of the oxide. The UV irradiation during the PMA excites the electrons from the accumulation layer, and the built-in electric field makes the electron injection into the oxide much easier. The electrons injected into the oxide recombine with the trapped holes, which have caused a large negative flat band voltage shift after the UV wet oxidation, and also ionize the H{sub 2}O molecules. The ionization results in the electron stimulated dissociation of H{sub 2}O molecules and the decreased interface trap density.

Inhibition effect on lipid oxidation of irradiated pork by adding hawthorn flavonoid extract

International Nuclear Information System (INIS)

Wang Xiaoming; Liu Chao; Cao Lei; Li Kexi

2011-01-01

The antioxidant activity of hawthorn flavonoid extract and its inhibition effect on irradiated pork lipid oxidant were investigated. The results showed that hawthorn flavonoids had efficient scavenging effect on DPPH free radicals (DPPH ·), and the scavenging rate reached 56% while 2 ml of 0.035 mg/ml hawthorn flavonoid extract was added. Hawthorn flavonoid extract can inhibition the lipid oxidation of irradiated pork effectively and it showed a stronger inhibition ability while the hawthorn flavonoid extract were used together with Vc. It is concluded that can decrease the lipid oxidation of pork, hawthorn flavonoid extract is a remarkable natural antioxidant. (authors)

Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

Science.gov (United States)

Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

2017-10-04

We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10 -3 S cm -1 ) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g -1 at 0.1 A g -1 ), better rate capability (64% capacity retention until 20 A g -1 ), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg -1 at 1 A g -1 ) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

Irradiation behavior of uranium oxide - Aluminum dispersion fuel

International Nuclear Information System (INIS)

Hofman, Gerard L.; Rest, Jeffrey; Snelgrove, James L.

1996-01-01

An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products and as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show that, with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 g U/cm 3 ) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼63% 235 U burnup). (author)

Irradiation behavior of uranium oxide-aluminum dispersion fuel

International Nuclear Information System (INIS)

Hofman, G.L.; Rest, J.; Snelgrove, J.L.

1996-01-01

An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO 2 -Al dispersion fuel. The aluminum-fuel interaction models were developed based on U 3 O 8 -Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products, as well as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show, that with the assumption that the correlations derived from U 3 O 8 are valid for UO 2 , the LEU UO 2 -Al with a 42% fuel volume loading (4 gm/cc) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 10 27 fissions m -3 (∼ 63% 235 U burnup)

Formation of gas-phase π-allyl radicals from propylene over bismuth oxide and γ-bismuth molybdate catalysts

International Nuclear Information System (INIS)

Martir, W.; Lunsford, J.H.

1981-01-01

Gas-phase π-allyl radicals were produced when propylene reacted over Bi 2 O 3 and γ-bismuth molybdate catalysts at 723 K. The pressure in the catalyst zone was varied between 5 x 10 -3 and 1 torr. The radicals were detected by EPR spectroscopy together with a matrix isolation technique in which argon was used as the diluent. The matrix was formed on a sapphire rod at 12 K which was located 33-cm downstream from the catalyst. Bismuth oxide was more effective in the production of gas-phase allyl radicals than γ-bismuth molybdate. By contrast α-bismuth molybdate was ineffective in forming allyl radicals and MoO 3 acted as a sink for radicals which were produced elsewhere in the system. Comparison of the π-allyl radical and the stable product concentrations over Bi 2 O 3 revealed that gas-phase radical recombination reactions served as a major pathway for the formation of 1,5-hexadiene. Addition of small amounts of gas-phase oxygen increased the concentration of allyl radicals, and at greater oxygen levels allyl peroxy radicals were detected. Because of the effect of temperature on the equilibrium between allyl and allyl peroxy radicals, the latter product must be formed in the cooler part of the system

Experimental and thermodynamic evaluation of the melting behavior of irradiated oxide fuels

International Nuclear Information System (INIS)

Adamson, M.G.; Aitken, E.A.; Caputi, R.W.

1985-01-01

Onset of melting is an important performance limit for irradiated UO 2 and UO 2 -based nuclear reactor fuels. Melting (solidus) temperatures are reasonably well known for starting fuel materials such as UO 2 and (U,PU)O 2 , however the influence of burnup on oxide fuel melting behavior continues to represent an area of considerable uncertainty. In this paper we report the results of a variety of melting temperature measurements on pseudo-binary fuel-fissia mixtures such as UO 2 -PUO 2 , UO 2 -CeO 2 , UO 2 -BaO, UO 2 -SrO, UO 2 -BaZrO 3 and UO 2 -SrZrO 3 . These measurements were performed using the thermal arrest technique on tungsten-encapsulated specimens. Several low melting eutectics, the existence of which had previously been inferred from post-irradiation examinations of high burnup mixed oxide fuels, were characterized in the course of the investigation. Also, an assessment of melting temperature changes in irradiated oxide fuels due to the production and incorporation of soluble oxidic fission products was performed by application of solution theory to the available pseudo-binary phase diagram data. The results of this assessment suggest that depression of oxide fuel solidus temperatures by dissolved fission products is substantially less than that indicated by earlier experimental studies. (orig.)

SYNTHESIS OF PROPYLENE FROM ETHANOL USING PHOSPHORUS-MODIFIED HZSM-5

Directory of Open Access Journals (Sweden)

R. S. Costa

Full Text Available Abstract Effects of phosphorus addition to HZSM-5 on ethanol conversion to propylene were evaluated. Catalysts were characterized by XRF, XRD, nitrogen adsorption, 27Al and 31P MAS NMR, n-propylamine and ammonia TPD. Increasing P content decreased the strength and density of acid total sites. Ethanol dehydration was carried out in a fixed bed reactor operating at atmospheric pressure. Conversion was around 100% for all catalysts. 1.2 wt% of P catalyst showed the highest propylene yield, and was used to evaluate temperature and ethanol partial pressure effects on the product distribution. The highest propylene accumulated productivity was obtained for an ethanol partial pressure of 0.4 atm. Propylene formation was favored in the temperature range 475-500 °C. Significant changes in the product distribution as a function of time on stream were observed at higher temperatures, suggesting stronger catalyst deactivation. The ethylene yield decreased up to 500 °C, rising significantly at 550 °C, possibly due to heavier product cracking reactions.

Thermoluminescent response of aluminium oxide thin films subject to gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Arrieta, A.; Escobar A, L.; Camps, E.; Villagran, E.; Gonzalez, P.R

2006-07-01

The thermoluminescent (TL) properties of amorphous aluminium oxide thin films (thicknesses as low as 0.3 {mu}m) subjected to gamma (Co-60) irradiation are reported. Aluminium oxide thin films were prepared by laser ablation from an Al{sub 2}O{sub 3} target using a Nd: YAG laser with emission at the fundamental line. The films were exposed to gamma radiation (Co-60) in order to study their TL response. Thermoluminescence glow curves exhibited two peaks at 110 and 176 C. The high temperature peak shows good stability and 30% fading in the first 5 days after irradiation. A linear relationship between absorbed dose and the thermoluminescent response for doses span from 150 mGy to 100 Gy was observed. These results suggest that aluminium oxide thin films are suitable for detection and monitoring of gamma radiation. (Author)

Coupling ultraviolet light and ultrasound irradiation with Conductive-Diamond Electrochemical Oxidation for the removal of progesterone

International Nuclear Information System (INIS)

Vidales, María J. Martín de; Barba, Silvia; Sáez, Cristina; Cañizares, Pablo; Rodrigo, Manuel A.

2014-01-01

Highlights: • Single sonolysis and photolysis technologies entail a slight progesterone removal and nil mineralization. • Synergistic effects of irradiating UV light and US are clearly observed in the oxidation rate. • The energy required by CDSEO and CDSPEO prevents against their application. • CDSEO mainly favors the mass transfer of organics to the conductive-diamond surface. • CDPEO promotes the formation of radicals in the bulk solution. - Abstract: This work focusses on the improvement of the efficiency of Conductive Diamond Electrochemical Oxidation (CDEO) by coupling US and UV irradiation in the degradation of progesterone from wastewater. Results show that CDEO is a promising technology for the degradation of progesterone, just the opposite of that observed for single sonolysis and photolysis technologies, which only entail a slight removal of progesterone and nil mineralization. Coupling UV light and US irradiations with CDEO seems to have a very positive effect, improving results obtained by single CDEO very significantly. Conductive Diamond Sono Electrochemical Oxidation (CDSEO) mainly seems to improve the transfer of pollutants to the conductive-diamond surface, while Conductive Diamond Photo Electrochemical Oxidation (CDPEO) seems to promote the formation of radicals from oxidants produced electrochemically. Soft oxidation conditions are obtained with the single application of both irradiation technologies, whereas an efficient mineralization is attained with CDEO, CDSEO, CDPEO and Conductive Diamond Sono-Photo Electrochemical Oxidation (CDSPEO). However, the high energy demands of US irradiation technologies advices against the use of CDSEO and CDSPEO

Hole centers in γ-irradiated, oxidized Al2O3

International Nuclear Information System (INIS)

Lee, K.H.; Holmberg, G.E.; Crawford, J.H. Jr.

1976-01-01

ESR observations of centers with S = 1/2, g approximately equal to 2, S = 1, g approximately equal to 2 have been made at 77 K on oxidized Al 2 O 3 after γ-irradiation at 30 0 C. From the radiation growth data, it is shown that the S = 1/2 centers are precursors of the S = 1 centers. In addition, when the S = 1 centers anneal out at about 110 0 C, the S = 1/2 centers reappear and eventually anneal out at about 260 0 C. Previously Gamble (Gamble, F.T.; Ph.D. Thesis, U. of Connecticut (1963)) and Cox (Cox, R.T.; Ph.D. Thesis, U. of Grenoble (1972) unpublished), respectively, observed S = 1/2 and S = 1 paramagnetic centers in electron-irradiated nominally pure Al 2 O 3 and γ-irradiated, oxidized, titanium-doped Al 2 O 3 . The models proposed for these centers were one hole and two holes trapped on oxygen ions adjacent to Al 3+ vacancies. Our results further substantiate these models. (author)

Ion irradiation studies of oxide ceramics

International Nuclear Information System (INIS)

Zinkle, S.J.

1988-01-01

This paper presents the initial results of an investigation of the depth-dependent microstructures of three oxide ceramics following ion implantation to moderate doses. The implantations were performed using ion species that occur as cations in the target material; for example, Mg + ions were used for MgO and MgAl 2 O 4 (spinel) irradiations. This minimized chemical effects associated with the implantation and allowed a more direct evaluation to be made of the effects of implanted ions on the microstructure. 11 refs., 14 figs

Isothermal oxidation behaviour of thermal barrier coatings with CoCrAlY bond coat irradiated by high-current pulsed electron beam

Energy Technology Data Exchange (ETDEWEB)

Cai, Jie [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Guan, Qingfeng, E-mail: guanqf@mail.ujs.edu.cn [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Hou, Xiuli [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Zhiping; Su, Jingxin; Han, Zhiyong [College of Science, Civil Aviation University of China, Tianjin 300300 (China)

2014-10-30

Highlights: • The original coarse surface was re-melted by pulsed electron beam irradiation. • Very fine grains were homogeneously dispersed on the irradiated coat surface. • A compact Al{sub 2}O{sub 3} scale was formed in irradiated TBCs at the onset of oxidation. • The selective oxidation of Al element avoided the formation of other oxides. • The irradiated coating has a much higher oxidation resistance. - Abstract: 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 Al{sub 2}O{sub 3} 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 Al{sub 2}O{sub 3}). The results indicate that TBCs with the irradiated bond coat have a much higher oxidation resistance.

Formation of tungsten oxide nanowires by ion irradiation and vacuum annealing

Science.gov (United States)

Zheng, Xu-Dong; Ren, Feng; Wu, Heng-Yi; Qin, Wen-Jing; Jiang, Chang-Zhong

2018-04-01

Here we reported the fabrication of tungsten oxide (WO3-x ) nanowires by Ar+ ion irradiation of WO3 thin films followed by annealing in vacuum. The nanowire length increases with increasing irradiation fluence and with decreasing ion energy. We propose that the stress-driven diffusion of the irradiation-induced W interstitial atoms is responsible for the formation of the nanowires. Comparing to the pristine film, the fabricated nanowire film shows a 106-fold enhancement in electrical conductivity, resulting from the high-density irradiation-induced vacancies on the oxygen sublattice. The nanostructure exhibits largely enhanced surface-enhanced Raman scattering effect due to the oxygen vacancy. Thus, ion irradiation provides a powerful approach for fabricating and tailoring the surface nanostructures of semiconductors.

Impact behaviour of polystyene/EPDM-rubber blends : influence of electron beam irradiation

NARCIS (Netherlands)

Gisbergen, van J.G.M.; Borgmans, C.P.J.H.; Sanden, van der M.C.M.; Lemstra, P.J.

1990-01-01

Electron beam irradiation of polystyrene/ethylene propylene diene monomer (PS/EPDM) blends, using polystyrene/polybutadiene block copolymers as compatibilizers, resulted in a two to three fold increase in Izod impact value. This greatly increased impact resistance is probably related to

Study of the chemisorption and hydrogenation of propylene on platinum by temperature-programed desorption

Energy Technology Data Exchange (ETDEWEB)

Tsuchiya, S.; Nakamura, M.; Yoshioka, N.

1978-01-01

Temperature-programed desorption (TPD) chromotograms of propylene adsorbed on platinum black in the absence or presence of hydrogen preadsorbed, admitted simultaneously, or admitted later, all showed four peaks at about 260/sup 0/ (A), 380/sup 0/ (B), 570/sup 0/ (C), and higher than 720/sup 0/K (D). Peaks A and B were identified as mixtures of propylene and propane, and peaks C and D were methane formed by thermal decomposition of the chemisorbed propylene during desorption. When nitrogen rather than helium was used as the carrier gas for the TPD, only delta-hydrogen was observed; this suggested that propylene was more strongly adsorbed on the platinum than hydrogen. Studies of the reactivities with propylene of the various types of chemisorbed hydrogen previously detected by TPD showed that propylene reacted with ..gamma..-hydrogen present on the surface in the form of hydrogen atoms chemisorbed on top of platinum atoms and with ..beta..-hydrogen, molecular hydrogen chemisorbed in a bridged form, but did not react with delta-hydrogen. Tables and graph.

Infrared cross-sections and integrated band intensities of propylene: Temperature-dependent studies

KAUST Repository

Es-sebbar, Et-touhami; Alrefae, Majed; Farooq, Aamir

2014-01-01

intensities of propylene are essential for quantitative measurements and atmospheric modeling. We measured absolute IR cross-sections of propylene using Fourier Transform Infrared (FTIR) Spectroscopy over the wavenumber range of 400-6500cm-1 and at gas

Ion irradiation-induced diffusion in bixbyite-fluorite related oxides: Dislocations and phase transformation

Energy Technology Data Exchange (ETDEWEB)

Rolly, Gaboriaud, E-mail: Rolly.gaboriaud@univ-poitiers.fr [Institut Pprime, CNRS-University of Poitiers, SP2MI-BP 30179, 86962 Chasseneuil-Futuroscope (France); Fabien, Paumier [Institut Pprime, CNRS-University of Poitiers, SP2MI-BP 30179, 86962 Chasseneuil-Futuroscope (France); Bertrand, Lacroix [CSIC – University of Sevilla, Avenida Américo Vespucio, 49, 41092 Sevilla (Spain)

2014-05-01

Ion-irradiation induced diffusion and the phase transformation of a bixbyite-fluorite related rare earth oxide thin films are studied. This work is focused on yttrium sesquioxide, Y{sub 2}O{sub 3}, thin films deposited on Si (1 0 0) substrates using the ion beam sputtering technique (IBS). As-deposited samples were annealed ant then irradiated at cryogenic temperature (80 K) with 260 keV Xe{sup 2+} at different fluences. The irradiated thin oxide films are characterized by X-ray diffraction. A cubic to monoclinic phase transformation was observed. Analysis of this phenomenon is done in terms of residual stresses. Stress measurements as a function of irradiation fluences were realised using the XRD-sin{sup 2}ψ method. Stress evolution and kinetic of the phase transformation are compared and leads to the role-played by the nucleation of point and extended defects.

Melatonin prevents inflammation and oxidative stress caused by abdominopelvic and total body irradiation of rat small intestine.

Science.gov (United States)

Guney, Y; Hicsonmez, A; Uluoglu, C; Guney, H Z; Ozel Turkcu, U; Take, G; Yucel, B; Caglar, G; Bilgihan, A; Erdogan, D; Nalca Andrieu, M; Kurtman, C; Zengil, H

2007-10-01

We investigated the day-night differences in intestinal oxidative-injury and the inflammatory response following total body (TB) or abdominopelvic (AP) irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g) in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period - 1 h after light onset) or evening (activity span - 13 h after light onset). Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively) to the irradiated rats. AP (P < 0.05) and TB (P < 0.05) irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS) levels. Melatonin treatment in the morning (P < 0.05) or evening (P < 0.05) decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05). Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

Melatonin prevents inflammation and oxidative stress caused by abdominopelvic and total body irradiation of rat small intestine

Directory of Open Access Journals (Sweden)

Y. Guney

2007-10-01

Full Text Available We investigated the day-night differences in intestinal oxidative-injury and the inflammatory response following total body (TB or abdominopelvic (AP irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period - 1 h after light onset or evening (activity span - 13 h after light onset. Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively to the irradiated rats. AP (P < 0.05 and TB (P < 0.05 irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS levels. Melatonin treatment in the morning (P < 0.05 or evening (P < 0.05 decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05. Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

A Combined Experimental and Theoretical Study on the Formation of Interstellar Propylene Oxide (CH3CHCH2O)—A Chiral Molecule

Science.gov (United States)

Bergantini, Alexandre; Abplanalp, Matthew J.; Pokhilko, Pavel; Krylov, Anna I.; Shingledecker, Christopher N.; Herbst, Eric; Kaiser, Ralf I.

2018-06-01

This work reveals via a combined experimental, computational, and astrochemical modeling study that racemic propylene oxide (c-C3H6O)—the first chiral molecule detected outside Earth toward the high-mass star-forming region Sagittarius B2(N)—can be synthesized by non-equilibrium reactions initiated by the effects of secondary electrons generated in the track of cosmic rays interacting with ice-coated interstellar grains through excited-state and spin-forbidden reaction pathways operating within low-temperature interstellar ices at 10 K. Our findings confront traditional hypotheses that thermal chemistries followed by processing of interstellar grains dictate the formation of complex organic molecules (COMs) in molecular clouds. Instead, we reveal a hitherto poorly quantified reaction class involving excited-state and spin-forbidden chemistry leading to racemic mixtures of COMs inside interstellar ices prior to their sublimation in star-forming regions. This fundamental production mechanism is of essential consequence in aiding our understanding of the origin and evolution of chiral molecules in the universe.

Irradiation Effect on Oxidative Condition and Tocopherol Content of Vegetable Oils

Directory of Open Access Journals (Sweden)

Konstantinos Sflomos

2007-06-01

Full Text Available The effect on induction period and tocopherol content after γ-irradiation onsamples of olive oil and seed oils (sunflower and soybean was determined. In seed oilsamples 0, 100, 200 and 300 ppm of δ-tocopherol were added before irradiation with 1, 2and 3kGy. The results of induction period showed that, after irradiation, all samplespresented a significant decreased in resistance to oxidation. However, this decrease wasminimized when δ-tocopherol was added. Irradiation significantly decreased the level oftocopherols. δ-Tocopherol appeared more sensitive in irradiation process than α- andγ-tocopherol. The addition of δ-tocopherol significantly reduced, in most cases, thedepletion of the other tocopherols.

Contribution to the development of the MARS beamline to study oxide dispersion strengthened steels (ODS) irradiated with neutrons using synchrotron source: secondary phases evolution under irradiation

International Nuclear Information System (INIS)

Menut, Denis

2016-01-01

X-Ray Diffraction (XRD) coupled with X-ray Absorption Fine Structure (XAFS) analyses at the MARS beamline of the synchrotron SOLEIL facility were used to study the microstructural evolution of oxides phases found in oxide dispersion strengthened steels (ODS) irradiated in Material Testing Reactors. Two hold generations of ODS steel grades (DY and MA957) irradiated up to high fluencies (∼75 dpa) were studied. These experiments have required specific developments, in particular a dedicated sample holder. An important milestone was overcome integrating the MARS beamline to the nuclearized facilities accessible for CEA. First, XRD analysis provide new results concerning intermediate sizes of precipitates (around 100 nm) essentially from crystallographic point of view, the nano-sized oxides (from 1 to 10 nm) being not detected, due to the material itself, sample preparation as thin foil and experimental set-up calibration. Secondly, XAFS analysis is not a discriminating technique as soon as the absorber atom is involved in the chemical composition of various precipitates found in ODS. Nevertheless, the stability of the Ti with a coordination number of 5 is evidenced whatever the irradiation conditions. As our experimental study was not able to detect the nano-sized oxides, an alternative way is to perform modeling approach of the behavior of massive oxides under irradiation, compared to experimental analyses under ion irradiations. We have shown that the defect fluorite is an intermediate phase of the crystal-to-amorphous phase transition of the pyrochlore oxide structure, whatever the irradiation conditions and the ratio of the cationic radii, the Ti coordination number remaining around 5 in the amorphous state. (author) [fr

Research on the structure in solution of optically active synthetic polymers (propylene polysulphide, propylene polyoxide, tertio-butyl polysulphide); Recherche de la structure en solution de polymeres synthetiques, optiquement actifs (polysulfure de propylene, polyoxyde de propylene, polysulfure de tertiobutyle)

Energy Technology Data Exchange (ETDEWEB)

Sarrazin, Brigitte

1971-03-15

It was proposed to study the structure of sulphur-containing synthetic polymers, stereo-regular, optically active in solution and able to adopt a spiral conformation, with special reference to propylene polysulphide. Two methods were used, the first mathematical (conformational energy calculations) and the second physico-chemical, essentially spectroscopic. By conformational analysis it is possible to choose the most probable structures liable to be adopted by a given polymer in solution while the spectro-polarimetric study should, in principle, invalidate or confirm certain of these hypotheses. The conformational energy calculations showed that in fact there is no energy conformation low enough to be stable in solution. Strictly speaking however we can refer to a region of stability in which steric hindrance is low and many energy minima exist. These minima are indistinguishable both by their energy values and by their spatial localizations and are all enclosed in the region bounded by the barriers due to steric hindrance. This uncertainty does not arise from approximations made in the calculations, but from the multitude of stereochemical structure possible. Investigations into the variation of the optical rotary dispersion and the circular dichroism as a function of temperature indicated the existence of three or more equilibrium states in the dioxane. The spectra appear to be the summation of the optical activities of the numerous simultaneously possible conformations. It appears that polymers, such as propylene polysulphide or propylene polyoxide do not have stable structures in solution. These are molecules of great flexibility possessing a large number of degrees of freedom. These properties distinguish them from the natural polymers, carrying precise information, such as DNA which must consequently have stable conformations. (author) [French] On s'est propose d'etudier la structure de polymeres synthetiques soufres, stereoreguliers, optiquement actifs en

Irradiation creep of the mixed oxide UPuO2

International Nuclear Information System (INIS)

Combette, Patrick; Milet, Claude

1976-01-01

The irradiation creep under compression of the mixed oxide UO 2 -PuO 2 was studied up to fission yields of 6x10 13 fcm -3 s -1 , under stresses -2 , in the temperature range 700-900 deg C. The creep rate is proportional to the applied stress and fission yield, athermal in the studied temperature range and non-dependent of burnup (up to 30000MWjt -1 ). In a sample under compression, swelling is observed due to the formation of fission products during the irradiation and the swelling rate is of the same order that in a cladded fuel element [fr

Inhibition of DNA repair by whole body irradiation induced nitric oxide leads to higher radiation sensitivity in lymphocytes

International Nuclear Information System (INIS)

Sharma, Deepak; Santosh Kumar, S.; Raghu, Rashmi; Maurya, D.K.; Sainis, K.B.

2007-01-01

Full text: It is well accepted that the sensitivity of mammalian cells is better following whole body irradiation (WBI) as compared to that following in vitro irradiation. However, the underlying mechanisms are not well understood. Following WBI, the lipid peroxidation and cell death were significantly higher in lymphocytes as compared to that in vitro irradiated lymphocytes. Further, WBI treatment of tumor bearing mice resulted in a significantly higher inhibition of EL-4 cell proliferation as compared to in vitro irradiation of EL-4 cells. The DNA repair was significantly slower in lymphocytes obtained from WBI treated mice as compared to that in the cells exposed to same dose of radiation in vitro. Generation of nitric oxide following irradiation and also its role in inhibition of DNA repair have been reported, hence, its levels were estimated under both WBI and in vitro irradiation conditions. Nitric oxide levels were significantly elevated in the plasma of WBI treated mice but not in the supernatant of in vitro irradiated cells. Addition of sodium nitroprusside (SNP), a nitric oxide donor to in vitro irradiated cells inhibited the repair of DNA damage and sensitized cells to undergo cell death. It also enhanced the radiation-induced functional impairment of lymphocytes as evinced from suppression of mitogen-induced IL-2, IFN-γ and bcl-2 mRNA expression. Administration of N G -nitro-L-arginine-methyl-ester(L-NAME), a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. Our results indicated that nitric oxide plays a role in the higher radiosensitivity of lymphocytes in vivo by inhibiting repair of DNA damage

Methanol to propylene. From development to commercialization

Energy Technology Data Exchange (ETDEWEB)

Haag, S.; Rothaemel, M. [Air Liquide Forschung und Entwicklung GmbH, Frankfurt am Main (Germany); Pohl, S.; Gorny, M. [Lurgie GmbH, Frankfurt am Main (Germany). Air Liquide Global E and C Solutions

2012-07-01

In the late 1990s the development of the so-called MTP {sup registered} (methanol-to-propylene) process, a Lurgi Technology (by Air Liquide Global E and C Solutions) started. This constitutes a novel route to a valuable product that would not rely on crude oil as feedstock (as conventional propylene production does), but instead utilizes coal or natural gas and potentially biomass. These alternative feedstocks are first converted to synthesis gas, cleaned, and then converted to methanol. The development of the methanol-to-propylene conversion was achieved in a close collaboration between R and D and engineering. Two pilot plants at the R and D center in Frankfurt and a demonstration plant in Norway have been used to demonstrate the yields, catalyst lifetime and product quality and to support the engineering team in plant design and scale-up. Especially the last item is important as it was clear from the very beginning that the first commercial MTP {sup registered} plant would already be world-scale, actually one of the largest propylene producing plants in the world. This required a safe and diligent scale-up as the MTP {sup registered} reactors in the commercial plant receive about 7,000 times the feed of the demo unit and as much as 100,000 times the feed of the pilot plant. The catalyst used is a zeolite ZSM-5 that was developed by our long-term cooperation partner Sued-Chemie (now Clariant). At the end of 2010, the first commercial MTP {sup registered} plant in Ningdong in the Chinese province of Ningxia was started up as part of a coal-to-chemicals complex owned by the Shenhua Ningxia Coal Industry Group. In this complex the complete chain starting from coal through to the final polypropylene product is realized. The customer successful started the polymer-grade propylene production in April 2011 and then announced in May 2011 that he sold the first 1000 tons of polypropylene made with propylene coming from the MTP {sup registered} unit. Following this

Effect of different antioxidants on lipid oxidation of irradiated cooked streaky pork

International Nuclear Information System (INIS)

Guo Shuzhen; Ha Yiming; Zhang Haiwei; Wang Feng; Liu Shuliang

2008-01-01

The effects of antioxidants on lipid oxidation of vacuum packaged irradiated cooked streaky pork were studied. The cooked streaky pork were added with 0.02% TeaPolyphenols (TP), rosemary, Tertiary butylhydroquinone (TBHQ), Butylated hydroxytoluene (BHT) and vitamin E separately, then were irradiated with 6 kGy, and stored at 4 degree C. The results showed that antioxidants can reduce the value of TBA, POV value of irradiated cooked streaky pork, and the effects of TBHQ and TP were better, than other antiatidins. (authors)

Status Epilepticus due to Intraperitoneal Injection of Vehicle Containing Propylene Glycol in Sprague Dawley Rats

Directory of Open Access Journals (Sweden)

Evon S. Ereifej

2017-01-01

Full Text Available Published reports of status epilepticus due to intraperitoneal injection containing propylene glycol in rats are sparse. In fact, there are no reports specifying a maximum safe dose of propylene glycol through intraperitoneal administration. We report here a case of unexpected seizures in Sprague Dawley rats after receiving an intraperitoneal injection containing propylene glycol. Nine-week-old, 225–250 gram male rats were reported to experience tremor progressing to seizures within minutes after given injections of resveratrol (30 mg/kg dissolved in a 40 : 60 propylene glycol/corn oil vehicle solution by direct intraperitoneal (IP slow bolus injection or via a preplaced intraperitoneal catheter. The World Health Organization suggests a maximum dose of 25 mg/kg/day of propylene glycol taken orally and no more than 25 mg/dL in blood serum, whereas the animals used in our study got a calculated maximum 0.52 g/kg (25 times lower dose. Blood tests from the seizing rat support a diagnosis of hemolysis and lactic acidosis which may have led to the seizures, all of which appeared to be a consequence of the propylene glycol administration. These findings are consistent with oral and intravenous administration of propylene glycol toxicity as previously reported in other species, including humans. To our knowledge, this report represents the first published case of status epilepticus due to an IP injection containing propylene glycol.

Vitamin C affects the antioxidative/oxidative status in rats irradiated with ultraviolet (UV) and infrared (IR) light

DEFF Research Database (Denmark)

Niemiec, T.; Sawosz, E.; Chwalibog, André

2006-01-01

Four grups of twenty growing Wistar rats were irradiated with either UV, IR, UV+IR light or were not irradiated (control). Ten rats from each group received a diet supplemented with 0.6% of L-ascorbic acid. The effects of the mega-dose of vitamin C were evaluated by changes in the antioxidative....../oxidative status. UV and IR radiation promoted oxidative DNA degradation in rat livers and supplementation with ascorbic acid strengthened the prooxidative effects on DNA oxidation in rats irradiated with UV or IR light. Vitamin C also increased the tiobarbituric acid reactive substances (TBARS) concentration...

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

International Nuclear Information System (INIS)

Ahn, D.U.; Nam, K.C.

2004-01-01

Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% α-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+α-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

Energy Technology Data Exchange (ETDEWEB)

Ahn, D.U. E-mail: duahn@iastate.edu; Nam, K.C

2004-10-01

Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% {alpha}-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+{alpha}-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

21 CFR 589.1001 - Propylene glycol in or on cat food.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug, and...

Radio-oxidation of an EPDM elastomer under weak or strong ionising radiations: measurement and modelling of dioxygen consumption

International Nuclear Information System (INIS)

Dely, N.

2005-10-01

Usually, the irradiation of polymers under ionising radiations occurs in air that is in the presence of oxygen. This leads to a radio oxidation process and to oxygen consumption. Our material is an EPDM elastomer (ethylene propylene 1,4 hexadiene) used as insulator in control-command cables in nuclear plants (Pressurised Water Reactor). A specific device has been conceived and built up during this PhD work for measuring very small oxygen consumptions with an accuracy of around 10%. Ionising radiations used are electrons at 1 MeV and carbon ions at 11 MeV per nucleon. Under both electron and ion irradiations, the influence of oxygen pressure on oxygen consumption has been studied in a very large range: between 1 and 200 mbar. In both cases, the yield of oxygen consumption is constant in-between 200 and 5 mbar. Then, at lower pressures, it decreases appreciably. On the other hand, the oxygen consumption during ion irradiation is four times smaller than during electron irradiation. This emphasizes the role of the heterogeneity of the energy deposition at a nano-metric scale. The adjustment of the experimental results obtained during electron irradiation with the general homogeneous steady-state kinetic model has allowed extracting all the values of the kinetic parameters for the chosen mechanism of radio oxidation. The knowledge of these numbers will allow us to face our results obtained during ion irradiation with a heterogeneous kinetic model under development. (author)

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

International Nuclear Information System (INIS)

Rouaud, Michel

1969-01-01

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

The Human Exposure Potential from Propylene Releases to the Environment

Directory of Open Access Journals (Sweden)

David A. Morgott

2018-01-01

Full Text Available A detailed literature search was performed to assess the sources, magnitudes and extent of human inhalation exposure to propylene. Exposure evaluations were performed at both the community and occupational levels for those living or working in different environments. The results revealed a multitude of pyrogenic, biogenic and anthropogenic emission sources. Pyrogenic sources, including biomass burning and fossil fuel combustion, appear to be the primary contributors to atmospheric propylene. Despite a very short atmospheric lifetime, measurable levels could be detected in highly remote locations as a result of biogenic release. The indoor/outdoor ratio for propylene has been shown to range from about 2 to 3 in non-smoking homes, which indicates that residential sources may be the largest contributor to the overall exposure for those not occupationally exposed. In homes where smoking takes place, the levels may be up to thirty times higher than non-smoking residences. Atmospheric levels in most rural regions are typically below 2 ppbv, whereas the values in urban levels are much more variable ranging as high as 10 ppbv. Somewhat elevated propylene exposures may also occur in the workplace; especially for firefighters or refinery plant operators who may encounter levels up to about 10 ppmv.

Irradiation of mixed UO2-PuO2 oxide samples for fast neutron reactor fuel elements

International Nuclear Information System (INIS)

Mikailoff, H.; Mustelier, J.; Bloch, J.; Conte, M.; Hayet, L.; Lauthier, J.C.; Leclere, J.

1968-01-01

Thermal flux irradiation testings of small mixed oxide pellets UPuO 2 fuel elements were performed in support of the fuel reference design for the Phenix fast reactor. The effects of different parameters (stoichiometry, pellet density, pellet clad gap). on the behaviour of the oxide (temperature distribution, microstructural changes, fission gas release) were investigated in various irradiation conditions. In particular, the effect of fuel density decrease and power rate increase on thermal performances were determined on short term irradiations of porous fuels. (authors) [fr

Effects of soy sauce and packaging method on volatile compounds and lipid oxidation of cooked irradiated beef patties

International Nuclear Information System (INIS)

Kim, Hyun-Wook; Lee, Soo-Yeon; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Ham, Yun-Kyung; Lee, Choong-Hee; Choi, Yun-Sang; Lee, Ju-Woon; Kim, Cheon-Jei

2014-01-01

The objective of this study is to determine the effect of soy sauce on volatile compounds and lipid oxidation of cooked irradiated beef patties. Sulfur-containing volatile components, which are produced by irradiation, were not found in all treatments. Volatile components derived from soy sauce, such as 3-hydroxy-2-butanone, acetic acid, 3-methyl-1-butanol and 2-methyl-1-butanol, were detected in beef patties containing soy sauce regardless of irradiation and packaging method. Volatile aldehydes, including hexanal, significantly decreased the irradiated beef patty prepared with soy sauce compared to those of irradiated beef patty made with NaCl at 1 day and 5 days after irradiation. In addition, combined use of vacuum packaging and soy sauce treatments could inhibit the formation of volatile compounds and 2-thiobarbituric acid reactive substances during chilled storage. Therefore, the use of soy sauce in cooked and irradiated beef could reduce the production of volatile components associated with the irradiation-induced off-flavor and lipid oxidation. - Highlights: • Soy sauce (SS) could inhibit volatiles cooked irradiated beef patties. • Vacuum packaging and SS treatment is effective to prevent lipid oxidation. • Hexanal content was highly correlated with TBA value of the irradiated beef patties

Protein aggregation in food models: effect of γ-irradiation and lipid oxidation

International Nuclear Information System (INIS)

Delincee, H.; Paul, P.

1981-01-01

Myoglobin and serum albumin have been irradiated in aqueous solution in the presence of varying amounts of carbohydrates and lipids, and the yield of protein aggregates has been determined by gel filtration. With myoglobin the formation of aggregates evolving from the reaction with oxidizing lipids was observed, which was not found for serum albumin. The production of protein-lipid complexes, in which lipid material was occluded in the high-molecular aggregates by physical forces was demonstrated. Gel filtration and gel electrophoresis, both in the presence of SDS, and thin-layer isoelectric focusing revealed distinct structural differenes between the protein aggregates induced by irradiation and the aggregates formed by interaction with oxidizing lipids

The role of nitric oxide radicals in removal of hyper-radiosensitivity by priming irradiation

International Nuclear Information System (INIS)

Edin, Nina Jeppesen; Sandvik, Joe Alexander; Pettersen, Erik Olai; Vollan, Hilde Synnove; Reger, Katharina; Görlach, Agnes

2013-01-01

In this study, a mechanism in which low-dose hyper-radiosensitivity (HRS) is permanently removed, induced by low-dose-rate (LDR) (0.2 - 0.3 Gy/h for 1 h) but not by high-dose-rate priming (0.3 Gy at 40 Gy/h) was investigated. One HRS-negative cell line (NHIK 3025) and two HRS-positive cell lines (T-47D, T98G) were used. The effects of different pretreatments on HRS were investigated using the colony assay. Cell-based ELISA was used to measure nitric oxide synthase (NOS) levels, and microarray analysis to compare gene expression in primed and unprimed cells. The data show how permanent removal of HRS, previously found to be induced by LDR priming irradiation, can also be induced by addition of nitric oxide (NO)-donor DEANO combined with either high-dose-rate priming or exposure to prolonged cycling hypoxia followed by reoxygenation, a treatment not involving radiation. The removal of HRS appears not to involve DNA damage induced during priming irradiation as it was also induced by LDR irradiation of cell-conditioned medium without cells present. The permanent removal of HRS in LDR-primed cells was reversed by treatment with inducible nitric oxide synthase (iNOS) inhibitor 1400W. Furthermore, 1400W could also induce HRS in an HRS-negative cell line. The data suggest that LDR irradiation for 1 h, but not 15 min, activates iNOS, and also that sustained iNOS activation is necessary for the permanent removal of HRS by LDR priming. The data indicate that nitric oxide production is involved in the regulatory processes determining cellular responses to low-dose-rate irradiation. (author)

Evaluation of some antioxidants in radiation vulcanized ethylene-propylene diene (EPDM) rubber

Energy Technology Data Exchange (ETDEWEB)

Abdel-Aziz, M.M.; Basfar, A.A. E-mail: abasfar@kacst.edu.sa

2001-12-01

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been used to study the oxidation of {gamma}-ray vulcanized ethylene-propylene diene rubber (EPDM) stabilized with various types of antioxidants. The antioxidants used were pentaerythrityl tetrakis(3,5-di-tert-butyl(-4-hydroxyphenyl))propionate (Irganox 1010), Irganox 1035, Irganox 1520D, as primary antioxidants; Irganox B561 and Irganox B900, as synergistic blends; hindered amine light stabilizer (HALS), i.e. Tinuvin 622 LD; N-isopropyl-N-phenyl-p-phenylene diamine (IPPD) and trimethyl quinoline (TMQ) and their mixtures. The measurements were carried out under atmospheric conditions. The effects of antioxidant type and its selected concentration were determined and mechanism of reaction proposed.

Growth of porous type anodic oxide films at micro-areas on aluminum exposed by laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Tatsuya [Graduate School of Engineering, Hokkaido University, N13-W8, Kita-Ku, Sapporo 060-8628 (Japan)], E-mail: kiku@eng.hokudai.ac.jp; Sakairi, Masatoshi [Graduate School of Engineering, Hokkaido University, N13-W8, Kita-Ku, Sapporo 060-8628 (Japan); Takahashi, Hideaki [Asahikawa National College of Technology, Syunkohdai, 2-2, 1-6, Asahikawa 071-8142 (Japan)

2009-11-30

Aluminum covered with pore-sealed anodic oxide films was irradiated with a pulsed Nd-YAG laser to remove the oxide film at micro-areas. The specimen was re-anodized for long periods to examine the growth of porous anodic oxide films at the area where substrate had been exposed by measuring current variations and morphological changes in the oxide during the re-anodizing. The chemical dissolution resistance of the pore-sealed anodic oxide films in an oxalic acid solution was also examined by measuring time-variations in rest potentials during immersion. The resistance to chemical dissolution of the oxide film became higher with increasing pore-sealing time and showed higher values at lower solution temperatures. During potentiostatic re-anodizing at five 35-{mu}m wide and 4-mm long lines for 72 h after the film was removed the measured current was found to increase linearly with time. Semicircular columnar-shaped porous type anodic oxide was found to form during the re-anodizing at the laser-irradiated area, and was found to grow radially, thus resulting in an increase in the diameter. After long re-anodizing, the central and top parts of the oxide protruded along the longitudinal direction of the laser-irradiated area. The volume expansion during re-anodizing resulted in the formation of cracks, parallel to the lines, in the oxide film formed during the first anodizing.

Pathfinder irradiation of advanced fuel (Th/U mixed oxide) in a power reactor

International Nuclear Information System (INIS)

Brant Pinheiro, R.

1993-01-01

Within the joint Brazilian-German cooperative R and D Program on Thorium Utilization in Pressurized Water Reactors carried out from 1979 to 1988 by Nuclebras/CDTN, KFA-Juelich, Siemens/KWU and NUKEM, a pathfinder irradiation of Th/U mixed oxide fuel in the Angra 1 nuclear power reactor was planned. The objectives of this irradiation testing, the irradiation strategy, the work performed and the status achieved at the end of the joint Program are presented. (author)

Effect of heavy ion irradiation and α+β phase heat treatment on oxide of Zr-2.5Nb pressure tube material

Energy Technology Data Exchange (ETDEWEB)

Choudhuri, Gargi, E-mail: gargi@barc.gov.in [Quality Assurance Division, BARC, Mumbai, 400085 (India); Mukherjee, P.; Gayathri, N. [Variable Energy Cyclotron Centre, Kolkata, 700064 (India); Kain, V.; Kiran Kumar, M.; Srivastava, D. [Material Science Division, BARC, Mumbai, 400085 (India); Basu, S. [Solid State Physics Division, BARC, Mumbai, 400085 (India); Mukherjee, D. [Quality Assurance Division, BARC, Mumbai, 400085 (India); Dey, G.K. [Material Science Division, BARC, Mumbai, 400085 (India)

2017-06-15

Effect of heavy-ion irradiation on the crystalline phase transformation of oxide of Zr-2.5Nb alloys has been studied. The steam-autoclaved oxide of pressure tube is irradiated with 306 KeV Ar{sup +9} ions at a dose of 3 × 10{sup 19} Ar{sup +9}/m{sup 2}. The damage profile has been estimated using “Stopping and Range of Ions in Matter” computer program. The variation of the crystal structure along the depth of the irradiated oxide have been characterized non-destructively by Grazing Incidence X-ray Diffraction technique and compared with unirradiated-oxide. The effect of different base metal microstructures on the characteristic of oxide has also been studied. Base metal microstructure as well as the cross-sectional oxide have been characterized using transmission electron microscope. Heavy ion irradiation can significantly alter the distribution of phases in the oxide of the alloy. The difference in chemical state of alloying element has also been found between unirradiated-oxide with that of irradiated-oxide using X-ray photo electron spectroscopy. Chemical state of Nb in steam autoclaved oxide is also altered when the base metal is α + β heat treated.

Micellar copolymerization of poly(acrylamide-g-propylene oxide): rheological evaluation and solution characterization; Copolimerizacao micelar de poli(acrilamida-g-oxido de propileno): avaliacao reologica e caracterizacao de suas solucoes

Energy Technology Data Exchange (ETDEWEB)

Sadicoff, Bianca L.; Brandao, Edimir M.; Lucas, Elizabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas]. E-mail: elucas@ima.ufrj.br; Amorim, Marcia C.V. [Universidade Estadual, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

2001-06-01

Graft copolymers of polyacrylamide and poly(propylene oxide) were synthesized by a micellar copolymerization technique. The rheological properties of the copolymers solutions were evaluated and compared with literature data for solutions of the same copolymers, synthesized by solution polymerization. The effect of hydrophobe content, salt addition and surfactant addition on the rheological properties were also investigated. Increasing hydrophobe content resulted in higher solution viscosities in the semi-dilute regime. Upon addition of salts, the hydrophobic groups associated to minimize their exposure to water. In the semi-dilute region, higher contents of surfactant added resulted in lower reduced viscosities of the polymer solutions. The copolymers were qualitatively characterized by infra-red spectrometry. (author)

Modulator Effect of Turmeric on Oxidative Damage in Whole Body Gamma Irradiated rats

International Nuclear Information System (INIS)

Amin, H.H.; Abdou, M.I.

2012-01-01

Because of its penetrating power and its ability to travel great distances, gamma rays are considered the primary hazard to the population during most radiological emergencies. So, there is a need to develop medical countermeasures to protect the first responders and remediation workers from biomedical effect of ionizing radiation. Turmeric has been reported to have many beneficial health effects, including a strong anti-oxidant effect, anti-inflammatory and anti-microbial properties. In the present study, turmeric was investigated as a therapeutic agent against hazards induced by ionizing radiation on kidney, liver, urinary and serum calcium levels and blood counts. A daily dose of 0.5 g/kg body weight was used in whole body gamma irradiated female rats with 3 Gy. Radiation effects were followed up for four weeks post irradiation. The results revealed that the administration of turmeric post-irradiation resulted in a significant inhibition in the frequency of radiation induced oxidative damage. It could be concluded that definite turmeric dose exerts a vital modulator role against gamma irradiation hazard

Magnetic, thermal and luminescence properties in room-temperature nanosecond electron-irradiated various metal oxide nanopowders

Science.gov (United States)

Sokovnin, S. Yu; Balezin, M. E.; Il’ves, V. G.

2018-03-01

By means of pulsed electron beam evaporation in vacuum of targets non-magnetic, in bulk state, Al2O3 and YSZ (ZrO2-8% Y2O3) oxides, magnetic nanopowders (NPs) with a high specific surface were produced. The NPs were subsequently irradiated in air by electrons with energy of 700 keV, using a URT-1 accelerator for 15 and 30 minutes. The magnetic, thermal, and pulsed cathodoluminescence (PCL) characteristics of NPs were measured before and after irradiation. It was established that the electron irradiation non-monotonically changes the magnetization of the pristine samples. To the contrary, a clear correlation between the intensity of PCL and the irradiation doses is found in the oxides. There was a decrease in the intensity of PCL after irradiation. Luminescent and thermal properties reflect the transformation of structural defects in NPs more strongly after the exposure to a pulsed electron beam in comparison with corresponding changes of the NPs magnetic response.

Protein Oxidation in the Lungs of C57BL/6J Mice Following X-Irradiation

Science.gov (United States)

Barshishat-Kupper, Michal; McCart, Elizabeth A.; Freedy, James G.; Tipton, Ashlee J.; Nagy, Vitaly; Kim, Sung-Yop; Landauer, Michael R.; Mueller, Gregory P.; Day, Regina M.

2015-01-01

Damage to normal lung tissue is a limiting factor when ionizing radiation is used in clinical applications. In addition, radiation pneumonitis and fibrosis are a major cause of mortality following accidental radiation exposure in humans. Although clinical symptoms may not develop for months after radiation exposure, immediate events induced by radiation are believed to generate molecular and cellular cascades that proceed during a clinical latent period. Oxidative damage to DNA is considered a primary cause of radiation injury to cells. DNA can be repaired by highly efficient mechanisms while repair of oxidized proteins is limited. Oxidized proteins are often destined for degradation. We examined protein oxidation following 17 Gy (0.6 Gy/min) thoracic X-irradiation in C57BL/6J mice. Seventeen Gy thoracic irradiation resulted in 100% mortality of mice within 127–189 days postirradiation. Necropsy findings indicated that pneumonitis and pulmonary fibrosis were the leading cause of mortality. We investigated the oxidation of lung proteins at 24 h postirradiation following 17 Gy thoracic irradiation using 2-D gel electrophoresis and OxyBlot for the detection of protein carbonylation. Seven carbonylated proteins were identified using mass spectrometry: serum albumin, selenium binding protein-1, alpha antitrypsin, cytoplasmic actin-1, carbonic anhydrase-2, peroxiredoxin-6, and apolipoprotein A1. The carbonylation status of carbonic anhydrase-2, selenium binding protein, and peroxiredoxin-6 was higher in control lung tissue. Apolipoprotein A1 and serum albumin carbonylation were increased following X-irradiation, as confirmed by OxyBlot immunoprecipitation and Western blotting. Our findings indicate that the profile of specific protein oxidation in the lung is altered following radiation exposure. PMID:28248270

Activity and selectivity of manganese oxides in alcohols Conversion as influenced by gamma-irradiation

International Nuclear Information System (INIS)

Doheim, M.M.; Ahmed, A.S.; El-Shobaky, G.A.

2002-01-01

Manganese oxide samples obtained from thermal decomposition of manganese carbonate at 400 and 600 deg C were subjected to different doses of g-irradiation within the range 0.2 to 1.6 MGy. The surface and catalytic properties of the above samples were studied using nitrogen adsorption isotherms measured at -196 deg C and catalytic conversion of ethanol and isopropanol at 300-400 deg C using micropulse technique. The results obtained revealed that manganese oxides obtained at 400 deg C consisted of a mixture of Mn 2 O 3 and MnO 2 while the samples calcined at 600 deg C composed entirely of Mn 2 O 3 . Gamma-irradiation resulted in a decrease in the particle size of manganese oxide phases with subsequent increase in their specific surface areas. Gamma-irradiation with 0.2 and 0.8 MGy effected a measurable progressive decrease in the catalytic activity in dehydration and dehydrogenation of both alcohols. However, the treated catalyst retained their initial activity upon exposure to a dose of 1.6 MGy. Also, g-irradiation increased the selectivities of the investigated solids towards dehydrogenation of both alcohols. The catalyst samples precalcined at 600 deg C exhibited higher catalytic activities than those precalcined at 400 deg C. (author)

Separation of Protactinium from Neutron Irradiated Thorium Oxide

International Nuclear Information System (INIS)

Dominguez, G.; Gutierrez, L.; Ropero, M.

1983-01-01

The chemical separation of thorium and protactinium can be carried out by leaching most of the last one, about 95%, with aqueous HF from neutron irradiated thorium oxide. This leaching reaction la highly favored by the transformation reaction of the ThO 2 material into ThF 4 . For both reactions, leaching and transformation, the reagents concentration, agitation speed and temperature influences were studied and the activation energies were found. (Author) 18 refs

Surface reactions of oxygen ions--2. Oxidation of alkenes by O/sup -/ on MgO

Energy Technology Data Exchange (ETDEWEB)

Aika, K.; Lunsford, J.H.

1978-08-10

Ethylene, propylene, 1-butene, and cis-2-butene were adsorbed on magnesium oxide containing O/sup -/ and the product distributions of their temperature-programed desorption compared with those of the desorption of possible intermediates (e.g., acetaldehyde) from untreated magnesium oxide. The results and ESR and IR spectroscopic studies suggested the alkenes reacted initially via hydrogen abstraction to form radicals; the 1-butene radical is oxidized to the alkoxide ion and forms mainly butadiene by a mechanism similar to that previously reported for alkane dehydrogenation; ethylene and propylene radicals form carboxylate ions which yield methane and carbonate ions as the main products.

Co-production of bio-oil and propylene through the hydrothermal liquefaction of polyhydroxybutyrate producing cyanobacteria.

Science.gov (United States)

Wagner, Jonathan; Bransgrove, Rachel; Beacham, Tracey A; Allen, Michael J; Meixner, Katharina; Drosg, Bernhard; Ting, Valeska P; Chuck, Christopher J

2016-05-01

A polyhydroxybutyrate (PHB) producing cyanobacteria was converted through hydrothermal liquefaction (HTL) into propylene and a bio-oil suitable for advanced biofuel production. HTL of model compounds demonstrated that in contrast to proteins and carbohydrates, no synergistic effects were detected when converting PHB in the presence of algae. Subsequently, Synechocystis cf. salina, which had accumulated 7.5wt% PHB was converted via HTL (15% dry weight loading, 340°C). The reaction gave an overall propylene yield of 2.6%, higher than that obtained from the model compounds, in addition to a bio-oil with a low nitrogen content of 4.6%. No propylene was recovered from the alternative non-PHB producing cyanobacterial strains screened, suggesting that PHB is the source of propylene. PHB producing microorganisms could therefore be used as a feedstock for a biorefinery to produce polypropylene and advanced biofuels, with the level of propylene being proportional to the accumulated amount of PHB. Copyright © 2016 Elsevier Ltd. All rights reserved.

Point defects and irradiation in oxides: simulations at the atomic scale

International Nuclear Information System (INIS)

Crocombette, J.P.

2005-11-01

The author gives an overview of his research activity since 1995. This activity concerns research in materials science, and more particularly the ageing of oxides present in the nuclear industry, or more generally, the evolution of these materials under irradiation. The first part deals with the investigation of point defects, and more particularly of the structures and energies of these defects. The author discusses results obtained on uranium dioxide, on amorphous silica, and on the solution of oxygen in silver. The second part deals with irradiation-induced damages in crystalline matrices storing radioactive actinides, and more particularly with the effect of alpha disintegration decay nuclei which are the main sources of long term irradiation in these materials

Lipid oxidation and volatile production in irradiated raw pork batters prepared with commercial soybean oil containing vitamin E

Energy Technology Data Exchange (ETDEWEB)

Jo, Cheorun; Ahn, D.U.; Byun, M.W. E-mail: mwbyun@kaeri.re.kr

2001-04-01

An emulsion-type raw pork batter was prepared using 10% (meat weight) of backfat or commercial soybean oil enriched with vitamin E to determine the effect of irradiation on lipid oxidation and volatile production during storage. Batters (approximately 100 g) were vacuum- or aerobically packaged and irradiated at 0, 2.5 or 4.5 kGy. Irradiation increased lipid oxidation of aerobically packaged raw pork batters prepared with both backfat and soybean oil. Lipid oxidation of vacuum-packaged pork batters was not influenced by irradiation except for the batter prepared with backfat at day 0. Aerobically packaged batters prepared with soybean oil had lower (P<0.05) TBARS than that with backfat, but vacuum-packaged ones were not different. The sum of volatile compounds with short retention time (<1.80) increased by irradiation, and with storage time except for aerobic packaging at day 7. The amount of total volatile compounds had an increasing trend until day 3, but not at day 7. Irradiation increased the production of total volatile compounds in the batters prepared with soybean oil and vacuum packaged, but irradiation effect on volatile production was not consistent with other treatments.

Lipid oxidation and volatile production in irradiated raw pork batters prepared with commercial soybean oil containing vitamin E

International Nuclear Information System (INIS)

Jo, Cheorun; Ahn, D.U.; Byun, M.W.

2001-01-01

An emulsion-type raw pork batter was prepared using 10% (meat weight) of backfat or commercial soybean oil enriched with vitamin E to determine the effect of irradiation on lipid oxidation and volatile production during storage. Batters (approximately 100 g) were vacuum- or aerobically packaged and irradiated at 0, 2.5 or 4.5 kGy. Irradiation increased lipid oxidation of aerobically packaged raw pork batters prepared with both backfat and soybean oil. Lipid oxidation of vacuum-packaged pork batters was not influenced by irradiation except for the batter prepared with backfat at day 0. Aerobically packaged batters prepared with soybean oil had lower (P<0.05) TBARS than that with backfat, but vacuum-packaged ones were not different. The sum of volatile compounds with short retention time (<1.80) increased by irradiation, and with storage time except for aerobic packaging at day 7. The amount of total volatile compounds had an increasing trend until day 3, but not at day 7. Irradiation increased the production of total volatile compounds in the batters prepared with soybean oil and vacuum packaged, but irradiation effect on volatile production was not consistent with other treatments

Polymerization of calcium caseinates solutions induced by gamma irradiation

International Nuclear Information System (INIS)

Lacroix, M.; Jobin, M.; Mezgheni, E.; Srour, M.; Boileau, S.

1998-01-01

Solutions of calcium caseinate (5%) combined with propylene glycol (PG) or triethylene glycol(TEG) (0, 2.5% and 5%) and used for the development of edible films and coatings, were irradiated at doses between 0 to 128 kGy. Solutions were chromatographed through toyopearl HW 55F resin to observe the effect of irradiation on cross-link reactions. In unirradiated calcium caseinate solutions, two peaks could be observed (fractions 30 and 37) while samples irradiated at 64 kGy and 128 kGy showed one shifted peak at fraction 32 and 29 respectively. No effect of the plasticizers was observed. According to proteins standards of knowed molecular weights, the molecular weight of calcium caseinate increased approximately 10 times when irradiated at 128 kGy and 5 times when irradiated at 64 kGy. The physico-chemical properties of bio-films prepared with the irradiated solutions, demonstrated that tensile strength at break increased with increase of irradiation dose. A maximum dose was obtained at 16 kGy

Dietary vitamin E affects lipid oxidation and total volatiles of irradiated raw turkey meat

International Nuclear Information System (INIS)

Ahn, D.U.; Sell, J.L.; Jeffery, M.; Jo, C.; Chen, X.; Lee, J.I.

1997-01-01

Breast and leg meat patties, prepared from turkeys fed diets containing 25, 200, 400 or 600 IU of dl-alpha-tocopheryl acetate (TA) per kg diet, were irradiated at 0 or 2.5 kGy with vacuum or loose packaging. The effects of dietary TA on storage stability and production of volatiles in irradiated raw turkey meat were determined. Dietary TA at 200 IU/kg decreased lipid oxidation and reduced total volatiles of raw turkey patties after 7-days of storage. However, the antioxidant effects of dietary TA were more notable when the patties were loosely packaged than when vacuum-packaged. Irradiation increased lipid oxidation of raw turkey meats only when loosely packaged but had limited effects on formation of total volatiles after storage at 4 degrees C for 7 days or longer

Synchrotron X-ray diffraction investigations on strains in the oxide layer of an irradiated Zircaloy fuel cladding

Energy Technology Data Exchange (ETDEWEB)

Chollet, Mélanie, E-mail: melanie.chollet@psi.ch [Paul Scherrer Institute, NES, 5232 Villigen (Switzerland); Valance, Stéphane; Abolhassani, Sousan; Stein, Gene [Paul Scherrer Institute, NES, 5232 Villigen (Switzerland); Grolimund, Daniel [Paul Scherrer Institute, SLS, 5232 Villigen (Switzerland); Martin, Matthias; Bertsch, Johannes [Paul Scherrer Institute, NES, 5232 Villigen (Switzerland)

2017-05-15

For the first time the microstructure of the oxide layer of a Zircaloy-2 cladding after 9 cycles of irradiation in a boiling water reactor has been analyzed with synchrotron micro-X-ray diffraction. Crystallographic strains of the monoclinic and to some extent of the tetragonal ZrO{sub 2} are depicted through the thick oxide layer. Thin layers of sub-oxide at the oxide-metal interface as found for autoclave-tested samples and described in the literature, have not been observed in this material maybe resulting from irradiation damage. Shifts of selected diffraction peaks of the monoclinic oxide show that the uniform strain produced during oxidation is orientated in the lattice and displays variations along the oxide layer. Diffraction peaks and their shifts from families of diffracting planes could be translated into a virtual tensor. This virtual tensor exhibits changes through the oxide layer passing by tensile or compressive components. - Highlights: •A Zircaloy-2 cladding irradiated 9 cycles was investigated thanks to synchrotron X-ray diffraction. •Microstructure and uniform strain through the oxide layer is revealed. •The m-ZrO{sub 2} uniform strain is oriented presenting compression along the (−111) plane. •Virtual tensor is built based on reflecting planes of families of grains. •Tensor components vary from tensile to compressive along the oxide layer.

Synchrotron X-ray diffraction investigations on strains in the oxide layer of an irradiated Zircaloy fuel cladding

International Nuclear Information System (INIS)

Chollet, Mélanie; Valance, Stéphane; Abolhassani, Sousan; Stein, Gene; Grolimund, Daniel; Martin, Matthias; Bertsch, Johannes

2017-01-01

For the first time the microstructure of the oxide layer of a Zircaloy-2 cladding after 9 cycles of irradiation in a boiling water reactor has been analyzed with synchrotron micro-X-ray diffraction. Crystallographic strains of the monoclinic and to some extent of the tetragonal ZrO 2 are depicted through the thick oxide layer. Thin layers of sub-oxide at the oxide-metal interface as found for autoclave-tested samples and described in the literature, have not been observed in this material maybe resulting from irradiation damage. Shifts of selected diffraction peaks of the monoclinic oxide show that the uniform strain produced during oxidation is orientated in the lattice and displays variations along the oxide layer. Diffraction peaks and their shifts from families of diffracting planes could be translated into a virtual tensor. This virtual tensor exhibits changes through the oxide layer passing by tensile or compressive components. - Highlights: •A Zircaloy-2 cladding irradiated 9 cycles was investigated thanks to synchrotron X-ray diffraction. •Microstructure and uniform strain through the oxide layer is revealed. •The m-ZrO 2 uniform strain is oriented presenting compression along the (−111) plane. •Virtual tensor is built based on reflecting planes of families of grains. •Tensor components vary from tensile to compressive along the oxide layer.

Transmission electron microscopy study of the heavy-ion-irradiation-induced changes in the nanostructure of oxide dispersion strengthened steels

Science.gov (United States)

Rogozhkin, S. V.; Bogachev, A. A.; Orlov, N. N.; Korchuganova, O. A.; Nikitin, A. A.; Zaluzhnyi, A. G.; Kozodaev, M. A.; Kulevoy, T. V.; Kuibeda, R. P.; Fedin, P. A.; Chalykh, B. B.; Lindau, R.; Hoffman, Ya.; Möslang, A.; Vladimirov, P.; Klimenkov, M.

2017-07-01

Transmission electron microscopy was used to study the effect of heavy-ion irradiation on the structure and the phase state of three oxide dispersion strengthened (ODS) steels: ODS Eurofer, ODS 13.5Cr, and ODS 13.5Cr-0.3Ti (wt %). Samples were irradiated with iron and titanium ions to fluences of 1015 and 3 × 1015 cm-2 at 300, 573, and 773 K. The study of the region of maximum radiation damage shows that irradiation increases the number density of oxide particles in all samples. The fraction of fine inclusions increases in the particle size distribution. This effect is most pronounced in the ODS 13.5Cr steel irradiated with titanium ions at 300 K to a fluence of 3 × 1015 cm-2. It is demonstrated that oxide inclusions in ODS 13.5Cr-0.3Ti and ODS 13.5Cr steels are more stable upon irradiation at 573 and 773 K than upon irradiation at 300 K.

Transesterification of used vegetable oil catalyzed by barium oxide under simultaneous microwave and ultrasound irradiations

International Nuclear Information System (INIS)

Martinez-Guerra, Edith; Gude, Veera Gnaneswar

2014-01-01

Graphical abstract: Transesterification reaction mediated by simultaneous microwave and ultrasound irradiations with barium oxide (BaO) heterogeneous catalyst. - Highlights: • Synergistic effect of simultaneous microwave/ultrasound irradiations was evaluated. • Yields were higher for the MW/US reactions compared to MW or US individually. • BaO catalyzed MW/US transesterification reaction is more environmental-friendly. • BaO catalyzed MW/US transesterification reaction provides better biodiesel yields. • Optimum power density must be identified for energy-efficient biodiesel production. - Abstract: This study presents a novel application of simultaneous microwave and ultrasound (MW/US) irradiations on transesterification of used vegetable oil catalyzed by barium oxide, heterogeneous catalyst. Experiments were conducted to study the optimum process conditions, synergistic effect of microwave and ultrasound irradiations and the effect of power density. From the process parametric optimization study, the following conditions were determined as optimum: 6:1 methanol to oil ratio, 0.75% barium oxide catalyst by wt.%, and 2 min of reaction time at a combined power output rate of 200 W (100/100 MW/US). The biodiesel yields were higher for the simultaneous MW/US mediated reactions (∼93.5%) when compared to MW (91%) and US (83.5%) irradiations individually. Additionally, the effect of power density and a discussion on the synergistic effect of the microwave and ultrasound mediated reactions were presented. A power density of 7.6 W/mL appears to be effective for MW, and MW/US irradiated reactions (94.4% and 94.7% biodiesel yields respectively), while a power density of 5.1 W/mL was appropriate for ultrasound irradiation (93.5%). This study concludes that the combined microwave and ultrasound irradiations result in a synergistic effect that reduces the heterogeneity of the transesterification reaction catalyzed by heterogeneous catalysts to enhance the biodiesel

Positron annihilation study of defects in electron-irradiated single crystal zinc oxide

Science.gov (United States)

To, C. K.; Yang, B.; Beling, C. D.; Fung, S.; Ling, C. C.; Gong, M.

2011-01-01

Pressurized melt grown zinc oxide (ZnO) single crystals purchased from Cermet Inc. were irradiated by 2MeV electrons with fluence of 6x1017cm-2. Isochronal annealing from 100°C-800°C was performed on the crystals under argon and air ambience. Variable Energy Doppler Broadening Spectroscopy (VEDBS) was carried out on both the as-grown and the irradiated samples at each annealing step. The migration, agglomeration and annealing of grown-in and irradiated-introduced defects were studied. It was observed that the grown-in vacancy-type defects concentration decreased at 300°C and 600 °C. For the irradiated sample annealed in argon, the positron trapping vacancy-type defect concentration decreased at 300°C and 600°C. Further annealing the as-grown and irradiated samples in argon increased the S parameter further. For the irradiated sample annealed in air, the vacancy-type defect concentration decreases at 300°C and 700°C.

Positron annihilation study of defects in electron-irradiated single crystal zinc oxide

Energy Technology Data Exchange (ETDEWEB)

To, C K; Yang, B; Beling, C D; Fung, S; Ling, C C [Department of Physics, University of Hong Kong (Hong Kong); Gong, M, E-mail: sfung@hkucc.hku.h, E-mail: edwardto04@yahoo.com.h [Department of Physics, Sichuan University, Chengdu (China)

2011-01-01

Pressurized melt grown zinc oxide (ZnO) single crystals purchased from Cermet Inc. were irradiated by 2 MeV electrons with fluence of 6x10{sup 17}cm{sup -2}. Isochronal annealing from 100 deg. C - 800 deg. C was performed on the crystals under argon and air ambience. Variable Energy Doppler Broadening Spectroscopy (VEDBS) was carried out on both the as-grown and the irradiated samples at each annealing step. The migration, agglomeration and annealing of grown-in and irradiated-introduced defects were studied. It was observed that the grown-in vacancy-type defects concentration decreased at 300 deg. C and 600 deg. C. For the irradiated sample annealed in argon, the positron trapping vacancy-type defect concentration decreased at 300 deg. C and 600 deg. C. Further annealing the as-grown and irradiated samples in argon increased the S parameter further. For the irradiated sample annealed in air, the vacancy-type defect concentration decreases at 300 deg. C and 700 deg. C.

Positron annihilation study of defects in electron-irradiated single crystal zinc oxide

International Nuclear Information System (INIS)

To, C K; Yang, B; Beling, C D; Fung, S; Ling, C C; Gong, M

2011-01-01

Pressurized melt grown zinc oxide (ZnO) single crystals purchased from Cermet Inc. were irradiated by 2 MeV electrons with fluence of 6x10 17 cm -2 . Isochronal annealing from 100 deg. C - 800 deg. C was performed on the crystals under argon and air ambience. Variable Energy Doppler Broadening Spectroscopy (VEDBS) was carried out on both the as-grown and the irradiated samples at each annealing step. The migration, agglomeration and annealing of grown-in and irradiated-introduced defects were studied. It was observed that the grown-in vacancy-type defects concentration decreased at 300 deg. C and 600 deg. C. For the irradiated sample annealed in argon, the positron trapping vacancy-type defect concentration decreased at 300 deg. C and 600 deg. C. Further annealing the as-grown and irradiated samples in argon increased the S parameter further. For the irradiated sample annealed in air, the vacancy-type defect concentration decreases at 300 deg. C and 700 deg. C.

Structural and morphological changes in pseudobarrier films of anodic aluminum oxide caused by irradiation with high-energy particles

International Nuclear Information System (INIS)

Chernykh, M.A.; Belov, V.T.

1988-01-01

We have studied the structural and morphological changes, occurring under the electron beam in pseudobarrier films of anodic aluminum oxide, prepared in seven different solutions and irradiated beforehand by protons of x-rays, with the aim of elucidating the structure of anodic aluminum oxides. An increased stability of the pseudobarrier films of anodic aluminum oxide has been observed towards the action of the electron beam of an UEMV-100K microscope at standard working regimes (75 keV) as a result of irradiation with protons or x-rays. A difference has been found to exist between structural and morphological changes of anodic aluminum oxide films, prepared in different solutions, when irradiated with high-energy particles. A structural and phase inhomogeneity of amorphous pseudobarrier films of anodic aluminum oxide has been detected and its influence on the character of solid-phase transformations under the maximum-intensity electron beam

Oxidation of Propylene on catalytic Pt-Cu/y alumina. (Part I) Characterization of catalysts of Pt-Cu/y alumina for chemisorption of H2

International Nuclear Information System (INIS)

Carballo, Luis M; Zea, Hugo R

1999-01-01

In this work the effect of the composition of catalysts of Pt-Cu/y-alumina is analyzed on the superficial area it reactivates corresponding to the total oxidation of propylene. The experimental essays were also made in a differential reactor that was used so much for the characterization of the catalyst in situ by means of the measurement of the selective chemisorption of H 2 , the effects and the bimetallic interactions are discussed that frequently happen in the supported catalysts. Starting from the studies of chemical adsorption of H 2 on the supported catalysts of Pt-Cu was, by means of the application of the theory of the regular solution to the surface of the glasses and keeping in mind that the H 2 it adsorbs chemically only on the superficial atoms of Pt (it was observed that the hydrogen not it chemi-absorb on the Cu) that the Cu atoms are segregated to the surface of the bimetallic crystals

Chemical and enzymatic stability of amino acid prodrugs containing methoxy, ethoxy and propylene glycol linkers.

Science.gov (United States)

Gupta, Deepak; Gupta, Sheeba Varghese; Lee, Kyung-Dall; Amidon, Gordon L

2009-01-01

We evaluated the chemical and enzymatic stabilities of prodrugs containing methoxy, ethoxy and propylene glycol linkers in order to find a suitable linker for prodrugs of carboxylic acids with amino acids. l-Valine and l-phenylalanine prodrugs of model compounds (benzoic acid and phenyl acetic acid) containing methoxy, ethoxy and propylene glycol linkers were synthesized. The hydrolysis rate profile of each compound was studied at physiologically relevant pHs (1.2, 4, 6 and 7.4). Enzymatic hydrolysis of propylene glycol containing compounds was studied using Caco-2 homogenate as well as purified enzyme valacyclovirase. It was observed that the stability of the prodrugs increases with the linker length (propyl > ethyl > methyl). The model prodrugs were stable at acidic pH as compared to basic pH. It was observed that the prodrug with the aliphatic amino acid promoiety was more stable compared to its aromatic counterpart. The comparison between benzyl and the phenyl model compounds revealed that the amino acid side chain is significant in determining the stability of the prodrug whereas the benzyl or phenyl carboxylic acid had little or no effect on the stability. The enzymatic activation studies of propylene glycol linker prodrug in the presence of valacyclovirase and cell homogenate showed faster generation of the parent drug at pH 7.4. The half-life of prodrugs at pH 7.4 was more than 12 h, whereas in the presence of cell homogenate the half-lives were less than 1 h. Hydrolysis by Caco-2 homogenate generated the parent compound in two steps, where the prodrug was first converted to the intermediate, propylene glycol benzoate, which was then converted to the parent compound (benzoic acid). Enzymatic hydrolysis of propylene glycol containing prodrugs by valacyclovirase showed hydrolysis of the amino acid ester part to generate the propylene glycol ester of model compound (propylene glycol benzoate) as the major product. The amino acid prodrugs containing methoxy

Texture, color, lipid oxidation and sensory acceptability of gamma-irradiated marinated anchovy fillets

Science.gov (United States)

Tomac, Alejandra; Cova, María C.; Narvaiz, Patricia; Yeannes, María I.

2015-01-01

The effect of gamma irradiation (0, 2, 3 and 4 kGy) on vacuum-packed marinated anchovy fillets was analyzed for their texture, color, lipid oxidation and sensory acceptability after 10 months under refrigeration. Marinated (3% acetic acid, 10% sodium chloride and 0.2% citric acid) Engraulis anchoita fillets were vacuum-packed and irradiated with a cobalt-60 source at a semi-industrial irradiation facility. The irradiation caused a slight increase in hardness values regardless of the applied dose but maintained a consistent texture over the 10 months, even though the control samples softened, most likely due to degradation. This hardness increase did not affect the textural sensory acceptability. Irradiation did not modify the color but still reduced color changes during storage, benefitting the product's quality. TBARS was increased in every sample throughout storage, but irradiation decreased these values. Sensory acceptability was not affected by gamma irradiation. Therefore, gamma irradiation could be successfully applied to this type of product for the purpose of shelf-life extension.

Ethylene glycol and propylene glycol ethers – Reproductive and developmental toxicity

Directory of Open Access Journals (Sweden)

Beata Starek-Świechowicz

2015-10-01

Full Text Available Both ethylene and propylene glycol alkyl ethers (EGAEs and PGAEs, respectively are widely used, mainly as solvents, in industrial and household products. Some EGAEs demonstrate gonadotoxic, embriotoxic, fetotoxic and teratogenic effects in both humans and experimental animals. Due to the noxious impact of these ethers on reproduction and development of organisms EGAEs are replaced for considerably less toxic PGAEs. The data on the mechanisms of testicular, embriotoxic, fetotoxic and teratogenic effects of EGAEs are presented in this paper. Our particular attention was focused on the metabolism of some EGAEs and their organ-specific toxicities, apoptosis of spermatocytes associated with changes in the expression of various genes that code for oxidative stress factors, protein kinases and nuclear hormone receptors. Med Pr 2015;66(5:725–737

Structural-morphological variations in pseudo-barrier films of anode aluminium oxide under irradiation with high-energy particles

International Nuclear Information System (INIS)

Chernykh, M.A.; Belov, V.T.

1988-01-01

Comparative study of structural-morphological variations under electron beam effect in pseudo-barrier films of anode aluminium oxide, obtained in seven different solutions and proton or X-rays pre-irradiated to determine structure peculiarities of anode aluminium oxides, is presented. Such study is a matter of interest from the solid-phase transformation theory point of view and for anode aluminium films application under radiation. Stability increase of pseudo-barrier films of anode aluminium oxide to the effect of UEhMV-100 K microscope electron beam at standard modes of operation (75 kV) due to proton or X-rays irradiation is found. Difference in structural-monorphological variations obtained in different solutions of anode aluminium films under high-energy particles irradiation is determined. Strucural-phase microinhomogeneity of amorphous pseudo-barrier films of anode aluminium oxide and its influence on solid-phase transformations character under electron bean of maximal intensity are detected

Correlation between locally deformed structure and oxide film properties in austenitic stainless steel irradiated with neutrons

Energy Technology Data Exchange (ETDEWEB)

Chimi, Yasuhiro, E-mail: chimi.yasuhiro@jaea.go.jp [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kitsunai, Yuji [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Kasahara, Shigeki [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chatani, Kazuhiro; Koshiishi, Masato [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Nishiyama, Yutaka [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2016-07-15

To elucidate the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in high-temperature water for neutron-irradiated austenitic stainless steels (SSs), the locally deformed structures, the oxide films formed on the deformed areas, and their correlation were investigated. Tensile specimens made of irradiated 316L SSs were strained 0.1%–2% at room temperature or at 563 K, and the surface structures and crystal misorientation among grains were evaluated. The strained specimens were immersed in high-temperature water, and the microstructures of the oxide films on the locally deformed areas were observed. The appearance of visible step structures on the specimens' surface depended on the neutron dose and the applied strain. The surface oxides were observed to be prone to increase in thickness around grain boundaries (GBs) with increasing neutron dose and increasing local strain at the GBs. No penetrative oxidation was observed along GBs or along surface steps. - Highlights: • Visible step structures depend on the neutron dose and the applied strain. • Local strain at grain boundaries was accumulated with the neutron dose. • Oxide thickness increases with neutron dose and local strain at grain boundaries. • No penetrative oxidation was observed along grain boundaries or surface steps.

Synthesis and characterization of some metal oxide nanocrystals by microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Rashad, M.; Gaber, A.; Abdelrahim, M. A.; Abdel-Baset, A. M. [Physics Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Moharram, A. H. [Physics Dept., College of Science and Arts, King Abdulaziz Univ., Rabigh 21911 (Saudi Arabia)

2013-12-16

Copper oxide and cobalt oxide (CuO, Co3O4) nanocrystals (NCs) have been successfully prepared in a short time using microwave irradiation. The resulted powders of nanocrystals (NCs) were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) measurements are also studied. Fourier-transform infrared (FT-IR) and UV–visible absorption spectroscopy of both kind of nanoparticels are illustrated. Optical absorption analysis indicated the direct band gap for both kinds of nanocrystals.

High-Flux Zeolitic Imidazolate Framework Membranes for Propylene/Propane Separation by Postsynthetic Linker Exchange.

Science.gov (United States)

Lee, Moon Joo; Kwon, Hyuk Taek; Jeong, Hae-Kwon

2018-01-02

While zeolitic imidazolate framework, ZIF-8, membranes show impressive propylene/propane separation, their throughput needs to be greatly improved for practical applications. A method is described that drastically reduces the effective thickness of ZIF-8 membranes, thereby substantially improving their propylene permeance (that is, flux). The new strategy is based on a controlled single-crystal to single-crystal linker exchange of 2-methylimidazole in ZIF-8 membrane grains with 2-imidazolecarboxaldehyde (ZIF-90 linker), thereby enlarging the effective aperture size of ZIF-8. The linker-exchanged ZIF-8 membranes showed a drastic increase in propylene permeance by about four times, with a negligible loss in propylene/propane separation factor when compared to as-prepared membranes. The linker-exchange effect depends on the membrane synthesis method. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Essential work of fracture analysis for starch filled poly(propylene carbonate) composites

International Nuclear Information System (INIS)

Wang, X.L.; Li, R.K.Y.; Cao, Y.X.; Meng, Y.Z.

2007-01-01

Starch filled poly(propylene carbonate) composites are environmental friendly materials. In this study, the fracture toughness of composites under mode I loading was determined by the essential work of fracture concept. The specific essential fracture work of the poly(propylene carbonate)/starch composites decreases with increasing the starch content, while the non-essential work term, βw p increases with increasing the starch content. In addition, the morphologies, thermal properties, thermo-mechanical properties were studied by scanning electron microscope, thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, respectively. The thermal and thermo-mechanical measurements revealed that increasing starch content led to an increase in glass transition temperature and thermal stability. Morphology observation indicates that poly(propylene carbonate) and starch have weak interfacial adhesion

Laser effects on graphene oxide irradiated in high vacuum

Czech Academy of Sciences Publication Activity Database

Torrisi, L.; Silipigni, L.; Cutroneo, Mariapompea

2018-01-01

Roč. 173, 1-2 (2018), s. 73-84 ISSN 1042-0150 R&D Projects: GA MŠk LM2015056; GA ČR GA16-05167S Institutional support: RVO:61389005 Keywords : graphene oxide * laser irradiation * laser-generated plasma * radiation effects Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 0.443, year: 2016

Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

Science.gov (United States)

Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

2018-03-01

Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

Effects of soy sauce and packaging method on volatile compounds and lipid oxidation of cooked irradiated beef patties

Science.gov (United States)

Kim, Hyun-Wook; Lee, Soo-Yeon; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Ham, Yun-Kyung; Lee, Choong-Hee; Choi, Yun-Sang; Lee, Ju-Woon; Kim, Cheon-Jei

2014-10-01

The objective of this study is to determine the effect of soy sauce on volatile compounds and lipid oxidation of cooked irradiated beef patties. Sulfur-containing volatile components, which are produced by irradiation, were not found in all treatments. Volatile components derived from soy sauce, such as 3-hydroxy-2-butanone, acetic acid, 3-methyl-1-butanol and 2-methyl-1-butanol, were detected in beef patties containing soy sauce regardless of irradiation and packaging method. Volatile aldehydes, including hexanal, significantly decreased the irradiated beef patty prepared with soy sauce compared to those of irradiated beef patty made with NaCl at 1 day and 5 days after irradiation. In addition, combined use of vacuum packaging and soy sauce treatments could inhibit the formation of volatile compounds and 2-thiobarbituric acid reactive substances during chilled storage. Therefore, the use of soy sauce in cooked and irradiated beef could reduce the production of volatile components associated with the irradiation-induced off-flavor and lipid oxidation.

Advanced Oxidation Treatment of Drinking Water and Wastewater Using High-energy Electron Beam Irradiation

Directory of Open Access Journals (Sweden)

Abbas Behjat

2007-03-01

Full Text Available Application of electron beam as a strong oxidation method for disinfection of drinking water and wastewater has been investigated. Drinking water samples were prepared from wells in rock zones in Yazd Province. Wastewater samples were collected from Yazd Wastewater Treatment Plant. Samples were irradiated by 10 MeV electron beam accelerator at Yazd Radiation Processing Center. The irradiation dose range varied from 0.5-5 kGy. Biological parameters and microbial agents such as aerobic mesophiles and coliforms including E. coli count before and after irradiation versus irradiation dose were obtained using MPN method. The data obtained from irradiated water and wastewater were compared with un-irradiated (control samples. The results showed a removal of 90% of all microorganisms at irradiation doses below 5 kGy, suggesting electron beam irradiation as an effective method for disinfection of wastewater.

Runinal and Intermediary Metabolism of Propylene Glycol in Lactating Holstein Cows

DEFF Research Database (Denmark)

Kristensen, Niels Bastian; Raun, Birgitte Marie Løvendahl

2007-01-01

Four lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in the mesenteric artery, mesenteric vein, hepatic portal vein, and hepatic vein were used in a cross-over design to study the metabolism of propylene glycol (PG).......Four lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in the mesenteric artery, mesenteric vein, hepatic portal vein, and hepatic vein were used in a cross-over design to study the metabolism of propylene glycol (PG)....

Research on the structure in solution of optically active synthetic polymers (propylene polysulphide, propylene polyoxide, tertio-butyl polysulphide)

International Nuclear Information System (INIS)

Sarrazin, Brigitte

1971-03-01

It was proposed to study the structure of sulphur-containing synthetic polymers, stereo-regular, optically active in solution and able to adopt a spiral conformation, with special reference to propylene polysulphide. Two methods were used, the first mathematical (conformational energy calculations) and the second physico-chemical, essentially spectroscopic. By conformational analysis it is possible to choose the most probable structures liable to be adopted by a given polymer in solution while the spectro-polarimetric study should, in principle, invalidate or confirm certain of these hypotheses. The conformational energy calculations showed that in fact there is no energy conformation low enough to be stable in solution. Strictly speaking however we can refer to a region of stability in which steric hindrance is low and many energy minima exist. These minima are indistinguishable both by their energy values and by their spatial localizations and are all enclosed in the region bounded by the barriers due to steric hindrance. This uncertainty does not arise from approximations made in the calculations, but from the multitude of stereochemical structure possible. Investigations into the variation of the optical rotary dispersion and the circular dichroism as a function of temperature indicated the existence of three or more equilibrium states in the dioxane. The spectra appear to be the summation of the optical activities of the numerous simultaneously possible conformations. It appears that polymers, such as propylene polysulphide or propylene polyoxide do not have stable structures in solution. These are molecules of great flexibility possessing a large number of degrees of freedom. These properties distinguish them from the natural polymers, carrying precise information, such as DNA which must consequently have stable conformations. (author) [fr

Metal adsorption of gamma-irradiated carboxymethyl cellulose/polyethylene oxide blend films

Science.gov (United States)

El-Naggar, Amal A.; Magida, M. M.; Ibrahim, Sayeda M.

2016-03-01

Blend films of different ratios of carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) were prepared by the solution casting method. To investigate the effect of irradiation on all properties of prepared blend, it was exposed to different gamma irradiation doses (10, 20, and 30 kGy). Physical properties such as gel fraction (GF) (%) and swelling (SW) (%) were investigated. It was found that the GF (%) increases with increasing irradiation dose up to 20 kGy, while SW (%) decreases with an increase in the irradiation doses for all blend compositions. Moreover, the structural and mechanical properties of the prepared films were studied. The results of the mechanical properties obtained showed that there is an improvement in these properties with an increase in both CMC and irradiation dose up to 20 kGy. The efficiency of metal ions uptake was measured using a UV spectrophotometer. The prepared films showed good tendency to absorb and release metal ions from aqueous media. Thus, the CMC/PEO film can be used in agricultural domain.

Radiation response of ODS ferritic steels with different oxide particles under ion-irradiation at 550 °C

Science.gov (United States)

Song, Peng; Morrall, Daniel; Zhang, Zhexian; Yabuuchi, Kiyohiro; Kimura, Akihiko

2018-04-01

In order to investigate the effects of oxide particles on radiation response such as hardness change and microstructural evolution, three types of oxide dispersion strengthened (ODS) ferritic steels (named Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS), mostly strengthened by Y-Ti-O, Y-Al-O and Y-Zr-O dispersoids, respectively, were simultaneously irradiated with iron and helium ions at 550 °C up to a damage of 30 dpa and a corresponding helium (He) concentration of ∼3500 appm to a depth of 1000-1300 nm. A single iron ion beam irradiation was also performed for reference. Transmission electron microscopy revealed that after the dual ion irradiation helium bubbles of 2.8, 6.6 and 4.5 nm in mean diameter with the corresponding number densities of 1.1 × 1023, 2.7 × 1022 and 3.6 × 1022 m-3 were observed in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS, respectively, while no such bubbles were observed after single ion irradiation. About 80% of intragranular He bubbles were adjacent to oxide particles in the ODS ferritic steels. Although the high number density He bubbles were observed in the ODS steels, the void swelling in Y-Ti-ODS, Y-Al-ODS and Y-Al-Zr-ODS was still small and estimated to be 0.13%, 0.53% and 0.20%, respectively. The excellent swelling resistance is dominantly attributed to the high sink strength of oxide particles that depends on the morphology of particle dispersion rather than the crystal structure of the particles. In contrast, no dislocation loops were produced in any of the irradiated steels. Nanoindentation measurements showed that no irradiation hardening but softening was found in the ODS ferritic steels, which was probably due to irradiation induced dislocation recovery. The helium bubbles in high number density never contributed to the irradiation hardening of the ODS steels at these irradiation conditions.

LYCOPENE EFFICIENCY IN THE MODULATION OF OXIDATIVE DAMAGE IN DIFFERENT TISSUES OF GAMMA IRRADIATED RATS

International Nuclear Information System (INIS)

EL-TAHAWY, N.A.; NADA, A.S.; REZK, R.G.

2008-01-01

Exposure to ionizing radiation induces oxidative stress that has been recognized as an important etiological factor in the causation of several chronic diseases. Lycopene, a carotenoid almost exclusively present in tomatoes and tomatoes products, is a lipid soluble antioxidant claimed to possess cardio protective and anticancer properties. The present study was designed to determine the possible modulator effects of lycopene on radiation-induced oxidative damage to liver, spleen and lung tissues. Animals were supplemented with lycopene (5 mg/kg body weight/ day) by gavages for two weeks before whole body exposure to gamma rays and within the period of irradiation (3 successive doses, each of 3 Gy at 72 hours intervals). Animals were sacrificed on the 3 r d day post the last irradiation session.The results obtained in the present study showed that whole body gamma irradiation produced oxidative stress manifested by significant elevation in lipid peroxides levels measured as thiobarbituric acid reactive substances (TBARS) associated with significant decrease of nitric oxide (NO) content. Non-significant change in total cupper (Cu) in the three tissues was recorded while significant increase of total iron (Fe) was observed in liver and spleen tissues only. Liver tissue of irradiated rats showed significant decrease in the activities of the antioxidant enzymes as superoxide dismutase (SOD) and catalase (CAT). In spleen tissues, there was a significant increase of SOD and significant decrease of CAT activities while in lung tissues, both SOD and CAT activities showed significant increase.Histological observations of photomicrograph of liver sections showed that radiation-induced sever damage obvious by dilated portal vein, ruptured hepatocytes, necrotic, pyknotic, karyolitic nuclei and vacuolated cytoplasm. In spleen tissue, radiation was induced degeneration of lymphatic nodules, dilation follicular artery and marked hemorrhage. In lung tissue, radiation- induces ill

Primary oxidation and reduction products in x-irradiated aspartic acid

International Nuclear Information System (INIS)

Adams, S.M.; Budzinski, E.E.; Box, H.C.

1976-01-01

The primary reduction products identified by ESR--ENDOR spectroscopy in single crystals of DL-aspartic acid hydrochloride irradiated at 4.2degreeK are anions formed by addition of an electron to the carbonyl oxygen atoms of the carboxylic acid groups. The main consequence of the oxidation process is to produce a hole centered mainly on atomic chlorine

Oxidative decomposition of aromatic hydrocarbons by electron beam irradiation

Science.gov (United States)

Han, Do-Hung; Stuchinskaya, Tatiana; Won, Yang-Soo; Park, Wan-Sik; Lim, Jae-Kyong

2003-05-01

Decomposition of aromatic volatile organic compounds (VOCs) under electron beam irradiation was studied in order to examine the kinetics of the process, to characterize the reaction product distribution and to develop a process of waste gas control technology. Toluene, ethylbenzene, o-, m-, p-xylenes and chlorobenzene were used as target materials. The experiments were carried out at doses ranging from 0.5 to 10 kGy, using a flow reactor utilized under electron beam irradiation. Maximum degrees of decomposition carried out at 10 kGy in air environment were 55-65% for “non-chlorinated” aromatic VOC and 85% for chlorobenzene. It was found that a combination of aromatic pollutants with chlorobenzene would considerably increase the degradation value up to nearly 50% compared to the same compounds in the absence of chlorine groups. Based on our experimental observation, the degradation mechanism of the aromatic compounds combined with chloro-compound suggests that a chlorine radical, formed from EB irradiation, induces a chain reaction, resulting in an accelerating oxidative destruction of aromatic VOCs.

Nano lead oxide and epdm composite for development of polymer based radiation shielding material: Gamma irradiation and attenuation tests

Science.gov (United States)

Özdemir, T.; Güngör, A.; Akbay, I. K.; Uzun, H.; Babucçuoglu, Y.

2018-03-01

It is important to have a shielding material that is not easily breaking in order to have a robust product that guarantee the radiation protection of the patients and radiation workers especially during the medical exposure. In this study, nano sized lead oxide (PbO) particles were used, for the first time, to obtain an elastomeric composite material in which lead oxide nanoparticles, after the surface modification with silane binding agent, was used as functional material for radiation shielding. In addition, the composite material including 1%, 5%, 10%, 15% and 20% weight percent nano sized lead oxide was irradiated with doses of 81, 100 and 120 kGy up to an irradiation period of 248 days in a gamma ray source with an initial dose rate of 21.1 Gy/h. Mechanical, thermal properties of the irradiated materials were investigated using DSC, DMA, TGA and tensile testing and modifications in thermal and mechanical properties of the nano lead oxide containing composite material via gamma irradiation were reported. Moreover, effect of bismuth-III oxide addition on radiation attenuation of the composite material was investigated. Nano lead oxide and bismuth-III oxide particles were mixed with different weight ratios. Attenuation tests have been conducted to determine lead equivalent values for the developed composite material. Lead equivalent thickness values from 0.07 to 0.65 (2-6 mm sample thickness) were obtained.

Lipid oxidation, color changes and volatiles production in irradiated pork sausage with different fat content and packaging during storage

International Nuclear Information System (INIS)

Jo, C.; Lee, J.I.; Ahn, D.U.

1999-01-01

Effects of irradiation on lipid oxidation, color and volatiles production in pork sausages with different fat content and packaging were determined. Sausages (with 4.7, 10.5 and 15.8% fat content) were sliced and vacuum-packaged either in oxygen-permeable or impermeable bags, irradiated (0 or 4.5 kGy) and stored at 4°C for 7 days. Lipid oxidation, color and volatiles productions were analyzed at 0, 3 and 7 days of storage. TBARS (2-thiobarbituric acid reactive substances) values of cooked pork sausages increased with the increase of fat content regardless of storage, irradiation or packaging types. Irradiated samples had higher TBARS than nonirradiated at 0 day but the difference disappeared during storage in both packaging types. Lightness of sausages (Hunter L-value) increased with the increase of fat content and storage time but was not affected by irradiation. In aerobic packaging, irradiation reduced Hunter a-values of pork sausages at 0 day but irradiation effect on a-value disappeared during storage. In vacuum packaging, however, irradiated samples had higher Hunter a-values than nonirradiated samples. Irradiation increased 1-heptene and total volatiles, but the amount of 1-heptene was not associated well with TBARS values of pork sausages. In both irradiated and nonirradiated pork sausages, aerobic packaging produced more volatiles than vacuum packaging during storage. It was concluded that irradiation and fat content had significant effects on lipid oxidation, color and volatiles production of cooked pork sausages during storage but that oxygen availability had a stronger effect than irradiation and fat content

Stability and kinetics of uranyl ion complexation by macrocycles in propylene carbonate

International Nuclear Information System (INIS)

Fux, P.

1984-06-01

A thermodynamic study of uranyl ion complexes formation with different macrocyclic ligands was realized in propylene carbonate as solvent using spectrophotometric and potentiometric techniques. Formation kinetics of two UO 2 complexes: a crown ether (18C6) and a coronand (22) was studied by spectrophotometry in propylene carbonate with addition of tetraethylammonium chlorate 0.1M at 25 0 C. Possible structures of complexes in solution are discussed [fr

Effects of a single glucocorticoid injection on propylene glycol-treated cows with clinical ketosis

NARCIS (Netherlands)

van der Drift, Saskia G A; Houweling, Martin; Bouman, Marina; Koets, Ad P; Tielens, Aloysius G M; Nielen, Mirjam; Jorritsma, Ruurd

2015-01-01

This study investigated the metabolic effects of glucocorticoids when administered to propylene glycol-treated cows with clinical ketosis. Clinical ketosis was defined by depressed feed intake and milk production, and a maximal score for acetoacetate in urine. All cows received 250 mL oral propylene

In Situ Spectroscopic Analysis of the Carbothermal Reduction Process of Iron Oxides during Microwave Irradiation

Directory of Open Access Journals (Sweden)

Jun Fukushima

2018-01-01

Full Text Available The effects of microwave plasma induction and reduction on the promotion of the carbothermal reduction of iron oxides (α-Fe2O3, γ-Fe2O3, and Fe3O4 are investigated using in situ emission spectroscopy measurements during 2.45 GHz microwave processing, and the plasma discharge (such as CN and N2 is measured during microwave E-field irradiation. It is shown that CN gas or excited CN molecules contribute to the iron oxide reduction reactions, as well as to the thermal reduction. On the other hand, no plasma is generated during microwave H-field irradiation, resulting in thermal reduction. Magnetite strongly interacts with the microwave H-field, and the reduction reaction is clearly promoted by microwave H-field irradiation, as well as thermal reduction reaction.

REALIGNED MODEL PREDICTIVE CONTROL OF A PROPYLENE DISTILLATION COLUMN

Directory of Open Access Journals (Sweden)

A. I. Hinojosa

Full Text Available Abstract In the process industry, advanced controllers usually aim at an economic objective, which usually requires closed-loop stability and constraints satisfaction. In this paper, the application of a MPC in the optimization structure of an industrial Propylene/Propane (PP splitter is tested with a controller based on a state space model, which is suitable for heavily disturbed environments. The simulation platform is based on the integration of the commercial dynamic simulator Dynsim® and the rigorous steady-state optimizer ROMeo® with the real-time facilities of Matlab. The predictive controller is the Infinite Horizon Model Predictive Control (IHMPC, based on a state-space model that that does not require the use of a state observer because the non-minimum state is built with the past inputs and outputs. The controller considers the existence of zone control of the outputs and optimizing targets for the inputs. We verify that the controller is efficient to control the propylene distillation system in a disturbed scenario when compared with a conventional controller based on a state observer. The simulation results show a good performance in terms of stability of the controller and rejection of large disturbances in the composition of the feed of the propylene distillation column.

Radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene in flow system, 8

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Ito, Masayuki; Machi, Sueo; Okamoto, Jiro.

1982-02-01

Seeded copolymerization of tetrafluoroethylene with propylene by radiation was carried out in a flow apparatus with pipe reactor at a pressure of 30 kg/cm 2 , a temperature of 40 0 C, a propylene fraction in monomer gas of 0.1, and at various dose rates. Amounts of dissolved monomer in latex increases in proportion to the polymer concentration, however, it becomes lower than that in equilibrium as polymerization proceeds. Propylene fraction in the dissolved monomer decreases with reaction time. Polymer concentration in latex increases accelerately with reaction time, and polymerization rate increases and tends to level off when the polymer concentration exceeds 100 g/l-H 2 O at higher dose rate. Polymerization rate is proportional to the 0.6 power of the dose rate at the polymer concentration of 50 g/l-H 2 O, and the power factor decreases from 0.46 to 0.39 with increasing the concentration from 100 to 150 g/l-H 2 O. Molecular weight of the polymer is proportional to the -0.17 power of the dose rate. The dose rate effects are explained by considering both first-order termination by degradative chain transfer to propylene and second-order termination by recombination. (author)

Structural evaluation of reduced graphene oxide in graphene oxide during ion irradiation: X-ray absorption spectroscopy and in-situ sheet resistance studies

Science.gov (United States)

Saravanan, K.; Jayalakshmi, G.; Suresh, K.; Sundaravel, B.; Panigrahi, B. K.; Phase, D. M.

2018-03-01

We report the structural evolution of reduced graphene oxide (rGO) in graphene oxide (GO) flakes during 1 MeV Si+ ion irradiation. In-situ electrical resistivity measurements facilitate monitoring the sheet resistance with the increase in the fluence. The electrical sheet resistance of the GO flake shows the exponential decay behaviour with the increasing ion fluence. Raman spectra of the GO flake reveal the increase in the ID/IG ratio, indicating restoration of the sp2 network upon irradiation. The C/O ratio estimated from resonant Rutherford backscattering spectrometry analysis directly evidenced the reduction of oxygen moieties upon irradiation. C K-edge X-ray absorption near edge structure spectra reveal the restoration of C=C sp2-hybridized carbon atoms and the removal of oxygen-containing functional groups in the GO flake. STM data reveal the higher conductance in the rGO regime in comparison with the regime, where the oxygen functional groups are present. The experimental investigation demonstrates that the ion irradiation can be employed for efficient reduction of GO with tunable electrical and structural properties.

First results from electron-photon damage equivalence studies on a generic ethylene-propylene rubber

International Nuclear Information System (INIS)

Buckalew, W.H.

1986-04-01

As part of a simulator adequacy assessment program, the relative effectiveness of electrons and photons to produce damage in a generic ethylene propylene rubber (EPR) has been investigated. The investigation was limited in extent in that a single EPR material, in three thickness, was exposed to Cobalt-60 photons and three electron beam energies. Basing material damage on changes in the EPR mechanical properties elongation and tensile strength, we observed that EPR damage was a smoothly varying function of absorbed energy and independent of irradiating particle type. EPR damage tracked equally well as a function of both incident particle energy and material front surface dose. Based on these preliminary data, we tentatively concluded that a correlation between particle, particle energy, and material damage (as measured by changes in material elongation and/or tensile strength) has been demonstrated. 14 figs

La consommation de propylène en Europe occidentale Propylene Consumption in Western Europe

Directory of Open Access Journals (Sweden)

Barraqué M.

2006-11-01

'éthylène; - le craquage du méthanol. The needs of Western Europe for propylene used in petrochemistry are currently 7. 4 x 10 to the power of 6 metric tons per year. In the coming years, the average rate of increase should be about 1. 8 % per year. Hence in 1995 European petrochemicals should use about 8. 7 x 10 to the power of 6 tons of propylene,Most of this increase in consumption will be due to the sharp rise in polypropylene production and to a lesser extent in propylene oxide, isopropanol and 2-ethyl hexanol production. However, uses for acrylonitrile and cumene will remain fairly stable. Propylene consumption for butanol production should decrease. The share of propylene needs met by European steam crackers, which was 82% in 1986, should be less than 75% in 1995. It will be more and more necessary to turn to other sources of supply. In 1986 European refineries produced 1. 05 x 10 to the power of 6 tons of propylene used for petrochemicals, and imports amounted to 0. 3 x 10 to the power of 6 tons. In 1995 the difference between consumption and production by steam crackers could be beyond 2. 0 x 10 to the power of 6 tons. It seems improbable that catalytic cracking plants can make up for the deficit except if propylene yields were to increase a great deal. The construction of propylene/propane splitters can be expected along with an increase in imports. Likewise, due to the tension that risks could appear in propylene prices, the advantage of some synthesis routes now considered not to be profitable might increase. These new routes are :(a dehydrogenation of propane as is already being considered in other regions (Mexico, Indonesia, Malaysia;(b metathesis between ethylene and butenes-2, which themselves can be produced from ethylene;(c methanol cracking.

Propylene/propane mixture adsorption on faujasite sorbents

NARCIS (Netherlands)

Van Miltenburg, A.; Gascon, J.; Zhu, W.; Kapteijn, F.; Moulijn, J.A.

2008-01-01

The adsorption of propylene and propane on zeolite NaX with and without a saturated (36 wt%) amount of CuCl have been investigated. The single component adsorption isotherms could be well described with a Dual-Site Langmuir model. The dispersion of CuCl results in a decrease of the maximum

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

International Nuclear Information System (INIS)

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

1979-01-01

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

Texture, color, lipid oxidation and sensory acceptability of gamma-irradiated marinated anchovy fillets

International Nuclear Information System (INIS)

Tomac, Alejandra; Cova, María C.; Narvaiz, Patricia; Yeannes, María I.

2015-01-01

The effect of gamma irradiation (0, 2, 3 and 4 kGy) on vacuum-packed marinated anchovy fillets was analyzed for their texture, color, lipid oxidation and sensory acceptability after 10 months under refrigeration. Marinated (3% acetic acid, 10% sodium chloride and 0.2% citric acid) Engraulis anchoita fillets were vacuum-packed and irradiated with a cobalt-60 source at a semi-industrial irradiation facility. The irradiation caused a slight increase in hardness values regardless of the applied dose but maintained a consistent texture over the 10 months, even though the control samples softened, most likely due to degradation. This hardness increase did not affect the textural sensory acceptability. Irradiation did not modify the color but still reduced color changes during storage, benefitting the product's quality. TBARS was increased in every sample throughout storage, but irradiation decreased these values. Sensory acceptability was not affected by gamma irradiation. Therefore, gamma irradiation could be successfully applied to this type of product for the purpose of shelf-life extension. - Highlights: • Marinated anchovies were γ-irradiated at 2, 3 and 4 kGy and stored at 4 °C (10 months). • Irradiation slightly hardened the texture and reduced its softening during storage. • Irradiated marinades had good sensory acceptability without differences with controls. • Irradiation improved the quality by reducing texture softening and color changes

Point defects and irradiation in oxides: simulations at the atomic scale

International Nuclear Information System (INIS)

Crocombette, J.P.

2005-12-01

The studies done by Jean-Paul Crocombette between 1996 and 2005 in the Service de Recherches de Metallurgie Physique of the Direction de l'Energie Nucleaire in Saclay are presented in this Habilitation thesis. These works were part of the material science researches on the ageing, especially under irradiation, of oxides of interest for the nuclear industry. In this context simulation studies at the atomic scale were performed on two elementary components of ageing under irradiation : point defects and displacement cascades ; using two complementary simulation techniques : ab initio electronic structure calculations and empirical potential molecular dynamics. The first part deals with point defects : self defects (vacancies or interstitials) or hetero-atomic dopants. One first recalls the energetics of such defects in oxides, the specific features of defects calculations and the expected accuracy of these calculations. Then one presents the results obtained on uranium dioxide, oxygen in silver and amorphous silica. The second part tackles the modelling of disintegration recoil nuclei in various?displacement cascades created by crystalline matrices for actinide waste disposal. Cascade calculations give access to the amorphization mechanisms under irradiation of these materials. One thus predicts that the amorphization in zircon takes place directly in the tracks whereas in lanthanum zirconate, the amorphization proceeds through the accumulation of point defects. Finally the prospects of these studies are discussed. (author)

Action of microwave radiation in emulsion of oil demulsification by copolymers of poly (ethylene oxide-b-propylene oxide); Acao da radiacao micro-ondas na desemulsificacao de emulsoes de petroleo por copolimeros de poli(oxido de etileno-b-oxido de propileno)

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Bianca M.S.; Ramalho, Joao B.V.; Guimaraes, Regina C.L.; Guarnieri, Ricardo A. [Petrobras Petroleo Brasileiro - CENPES/TPEP/TPP, Rio de Janeiro, RJ (Brazil)], e-mail: bmachado@petrobras.com.br; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro, Instituto de Macromoleculas, Laboratorio de Macromoleculas e Coloides na Industria do Petroleo,Rio de Janeiro, RJ (Brazil)], e-mail: elucas@ima.ufrj.br

2011-07-01

Emulsions of water-in-petroleum are generally formed during crude oil production. The emulsion needs to be destabilized, along the process in the production units, so as to allow the water-oil separation. This process is accomplished by heating and addition of demulsifier, like poly (ethylene oxide-b-propylene oxide) which promotes the removal of the natural emulsifier from the water droplets interfaces. Normally, the conventional heating is used, but the microwave radiation has been suggested to heat de emulsions. The results obtained in this work show that microwave radiation can really enhance the demulsification rate of petroleum emulsions by gravitational mechanism. It is also shown that demulsification enhancement is greatly related to the selective and higher heating of the water phase induced by the microwave radiation, which causes the lowering of the interfacial film rigidity and the increase of the film drainage, after the demulsifier is added to the dispersed system. It was also observed that the higher the density, viscosity, acidity and asphaltenes content of the crude oil, the lower the demulsification rate. (author)

Accelerated thermal and radiation-oxidation combined degradation of electric cable insulation materials

International Nuclear Information System (INIS)

Yagi, Toshiaki; Seguchi, Tadao; Yoshida, Kenzo

1986-03-01

For the development of accelerated testing methodology to estimate the life time of electric cable, which is installed in radiation field such as a nuclear reactor containment vessel, radiation and thermal combined degradation of cable insulation and jacketing materials was studied. The materials were two types of formulated polyethylene, ethylene-propylene rubber, Hypalon, and Neoprene. With Co-60 γ-rays the materials were irradiated up to 0.5 MGy under vacuum and in oxygen under pressure, then exposed to thermal aging at elevated temperature in oxygen. The degradation was investigated by the tensile test, gelfraction, and swelling measurements. The thermal degradation rate for each sample increases with increase of oxygen concentration, i.e. oxygen pressure, during the aging, and tends to saturate above 0.2 MPa of oxygen pressure. Then, the effects of irradiation and the temperature on the thermal degradation rate were investigated at the oxygen pressure of 0.2 MPa in the temperature range from 110 deg C to 150 deg C. For all of samples irradiated in oxygen, the following thermal degradation rate was accelerated by several times comparing with unirradiated samples, while the rate of thermal degradation for the sample except Neoprene irradiated under vacuum was nearly equal to that of unirradiated one. By the analysis of thermal degradation rate against temperature using Arrhenius equation, it was found that the activation energy tends to decrease for the samples irradiated in oxidation condition. (author)

Protective Effect of Low Dose Gamma Irradiation against Oxidative Damage in Rats Administrated with Ferric- Nitrilotriacetate

International Nuclear Information System (INIS)

Mansonr, S.Z.

2009-01-01

Many studies have demonstrated the beneficial adaptive response of low dose gamma-irradiation. Low dose gamma-irradiation (LDR) might be effective for the prevention of various reactive oxygen species-related diseases. Ferric nitrilotriacetate (Fe-NTA) is a strong oxidant, which generates highly reactive hydroxyl radical and causes injuries of various organs including the kidney and liver. This study was designed to investigate the ability of low dose gamma-irradiation to restrain Fe-NT A induced oxidative stress. Sprague Dawley male albino rats were subjected to low dose gamma-irradiation (50 cGy). Animals were challenged with Fe-NT A (9 mg Fe/kg body weight, intraperitoneally). Results showed that Fe-NTA enhances lipid peroxidation (LPx) accompanied with reduction in glutathione (GSH) content, antioxidant enzymes, viz., glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and phase-U metabolizing enzyme glutathione-S-transferase (GST). Fe-NTA also enhances the concentration of blood urea nitrogen (BUN) and serum creatinine as well as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) activities. Exposure to low dose gamma- irradiation (3 h after Fe-NTA administration) resulted in a significant decrease in LPx, BUN, serum creatinine contents as well as ALT, AST and GGT enzyme activities. GSH content; GST and antioxidant enzymes were also recovered to significant level. Thus, our data suggest that exposure to LDR might be a useful antioxidant mediator to suppress the Fe-NTA induced-oxidative damage in rats

Protective Effect of Low Dose Gamma Irradiation against Oxidative Damage in Rats Administrated with Ferric- Nitrilotriacetate

International Nuclear Information System (INIS)

Mansonr, S.Z.

2008-01-01

Many studies have demonstrated the beneficial adaptive response of low dose gamma-irradiation. Low dose gamma-irradiation (LDR) might be effective for the prevention of various reactive oxygen species-related diseases. Ferric nitrilotriacetate (Fe-NTA) is a strong oxidant, which generates highly reactive hydroxyl radical and causes injuries of various organs including the kidney and liver. This study was designed to investigate the ability of low dose gamma-irradiation to restrain Fe-NT A induced oxidative stress. Sprague Dawley male albino rats were subjected to low dose gamma-irradiation (50 cGy). Animals were challenged with Fe-NT A (9 mg Fe/kg body weight, intraperitoneally). Results showed that Fe-NTA enhances lipid peroxidation (LPx) accompanied with reduction in glutathione (GSH) content, antioxidant enzymes, viz., glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and phase-U metabolizing enzyme glutathione-S-transferase (GST). Fe-NTA also enhances the concentration of blood urea nitrogen (BUN) and serum creatinine as well as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) activities. Exposure to low dose gamma- irradiation (3 h after Fe-NTA administration) resulted in a significant decrease in LPx, BUN, serum creatinine contents as well as ALT, AST and GGT enzyme activities. GSH content; GST and antioxidant enzymes were also recovered to significant level. Thus, our data suggest that exposure to LDR might be a useful antioxidant mediator to suppress the Fe-NTA induced-oxidative damage in rats

Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors

International Nuclear Information System (INIS)

Karahan, Aydin; Buongiorno, Jacopo

2010-01-01

An engineering code to model the irradiation behavior of UO 2 -PuO 2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named fuel engineering and structural analysis tool (FEAST-OXIDE). FEAST-OXIDE has several modules working in coupled form with an explicit numerical algorithm. These modules describe: (1) fission gas release and swelling, (2) fuel chemistry and restructuring, (3) temperature distribution, (4) fuel-clad chemical interaction and (5) fuel-clad mechanical analysis. Given the fuel pin geometry, composition and irradiation history, FEAST-OXIDE can analyze fuel and cladding thermo-mechanical behavior at both steady-state and design-basis transient scenarios. The code was written in FORTRAN-90 program language. The mechanical analysis module implements the LIFE algorithm. Fission gas release and swelling behavior is described by the OGRES and NEFIG models. However, the original OGRES model has been extended to include the effects of joint oxide gain (JOG) formation on fission gas release and swelling. A detailed fuel chemistry model has been included to describe the cesium radial migration and JOG formation, oxygen and plutonium radial distribution and the axial migration of cesium. The fuel restructuring model includes the effects of as-fabricated porosity migration, irradiation-induced fuel densification, grain growth, hot pressing and fuel cracking and relocation. Finally, a kinetics model is included to predict the clad wastage formation. FEAST-OXIDE predictions have been compared to the available FFTF, EBR-II and JOYO databases, as well as the LIFE-4 code predictions. The agreement was found to be satisfactory for steady-state and slow-ramp over-power accidents.

Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors

Energy Technology Data Exchange (ETDEWEB)

Karahan, Aydin, E-mail: karahan@mit.ed [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology, MA (United States); Buongiorno, Jacopo [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology, MA (United States)

2010-01-31

An engineering code to model the irradiation behavior of UO{sub 2}-PuO{sub 2} mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named fuel engineering and structural analysis tool (FEAST-OXIDE). FEAST-OXIDE has several modules working in coupled form with an explicit numerical algorithm. These modules describe: (1) fission gas release and swelling, (2) fuel chemistry and restructuring, (3) temperature distribution, (4) fuel-clad chemical interaction and (5) fuel-clad mechanical analysis. Given the fuel pin geometry, composition and irradiation history, FEAST-OXIDE can analyze fuel and cladding thermo-mechanical behavior at both steady-state and design-basis transient scenarios. The code was written in FORTRAN-90 program language. The mechanical analysis module implements the LIFE algorithm. Fission gas release and swelling behavior is described by the OGRES and NEFIG models. However, the original OGRES model has been extended to include the effects of joint oxide gain (JOG) formation on fission gas release and swelling. A detailed fuel chemistry model has been included to describe the cesium radial migration and JOG formation, oxygen and plutonium radial distribution and the axial migration of cesium. The fuel restructuring model includes the effects of as-fabricated porosity migration, irradiation-induced fuel densification, grain growth, hot pressing and fuel cracking and relocation. Finally, a kinetics model is included to predict the clad wastage formation. FEAST-OXIDE predictions have been compared to the available FFTF, EBR-II and JOYO databases, as well as the LIFE-4 code predictions. The agreement was found to be satisfactory for steady-state and slow-ramp over-power accidents.

Structure and activity of tellurium-cerium oxide acrylonitrile catalysts

International Nuclear Information System (INIS)

Bart, J.C.J.; Giordano, N.

1982-01-01

Ammoxidation of propylene to acrylonitrile (ACN) was investigated over various silica-supported (Te,Ce)O catalysts at 360 and 440 0 C. The binary oxide system used consists of a single nonstoichiometric fluorite-type phase α-(Ce,Te)O 2 up to about 80 mole% TeO 2 and a tellurium-saturated solid solution β-(Ce,Te)O 2 at higher tellurium concentrations. The ACN yield varies almost linearly with the tellurium content of (Ce,Te)O 2 . The β-(Ce,Te)O 2 phase is the most active component of the system (propylene conversion and ACN selectivity at 440 C of 76.7 and 74%, respectively) and is slightly more selective to ACN than α-Te0 2 . Tellurium reduces the overoxidation properties of cerium and selective oxidation occurs through Te(IV)-bonded oxygen

Enhancement of methane gas sensing characteristics of graphene oxide sensor by heat treatment and laser irradiation.

Science.gov (United States)

Assar, Mohammadreza; Karimzadeh, Rouhollah

2016-12-01

The present study uses a rapid, easy and practical method for cost-effective fabrication of a methane gas sensor. The sensor was made by drop-casting a graphene oxide suspension onto an interdigital circuit surface. The electrical conductivity and gas-sensing characteristics of the sensor were determined and then heat treatment and in situ laser irradiation were applied to improve the device conductivity and gas sensitivity. Real-time monitoring of the evolution of the device current as a function of heat treatment time revealed significant changes in the conductance of the graphene oxide sensor. The use of low power laser irradiation enhanced both the electrical conductivity and sensing response of the graphene oxide sensor. Copyright © 2016 Elsevier Inc. All rights reserved.

Numerical optimization of a transcritical CO2/propylene cascaded ...

Indian Academy of Sciences (India)

transcritical CO2/propylene cascade system with parallel compression ... specific volumes, low solidification temperature, low operating pressure of the ...... Kim M, Pettersen J and Bullard C W 2004 Fundamental process and system design ...

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

International Nuclear Information System (INIS)

Singh, Hemant Kr.; Avasthi, D.K.; Aggarwal, Shruti

2015-01-01

Highlights: •The objective is to study the effect of swift heavy ion (SHI) irradiation on photoanode of DSSC for better efficiency. •This work presents the effect of SHI irradiation on various Transparent conducting oxides (TCOs). •Effects are studied in terms of conductivity and transmittance of TCOs. •ITO-PET gives best results in comparison to ITO and FTO for DSSC application under SHI irradiation. -- Abstract: Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO 2 :F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In 2 O 3 :Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag +9 ions at fluences ranging from 3.0 × 10 11 ions/cm 2 to 3.0 × 10 13 ions/cm 2 . The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications

TEM in situ micropillar compression tests of ion irradiated oxide dispersion strengthened alloy

Energy Technology Data Exchange (ETDEWEB)

Yano, K.H., E-mail: kaylayano@u.boisestate.edu [Boise State University, 1910 University Drive, Boise, ID, 83725 (United States); Swenson, M.J. [Boise State University, 1910 University Drive, Boise, ID, 83725 (United States); Wu, Y. [Boise State University, 1910 University Drive, Boise, ID, 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID, 83401 (United States); Wharry, J.P. [Boise State University, 1910 University Drive, Boise, ID, 83725 (United States); Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States)

2017-01-15

The growing role of charged particle irradiation in the evaluation of nuclear reactor candidate materials requires the development of novel methods to assess mechanical properties in near-surface irradiation damage layers just a few micrometers thick. In situ transmission electron microscopic (TEM) mechanical testing is one such promising method. In this work, microcompression pillars are fabricated from a Fe{sup 2+} ion irradiated bulk specimen of a model Fe-9%Cr oxide dispersion strengthened (ODS) alloy. Yield strengths measured directly from TEM in situ compression tests are within expected values, and are consistent with predictions based on the irradiated microstructure. Measured elastic modulus values, once adjusted for the amount of deformation and deflection in the base material, are also within the expected range. A pillar size effect is only observed in samples with minimum dimension ≤100 nm due to the low inter-obstacle spacing in the as received and irradiated material. TEM in situ micropillar compression tests hold great promise for quantitatively determining mechanical properties of shallow ion-irradiated layers.

Effect of dietary alpha-tocopherol supplementation and gamma-irradiation on alpha-tocopherol retention and lipid oxidation in cooked minced chicken

International Nuclear Information System (INIS)

Galvin, K.; Morrissey, P.A.; Buckley, D.J.

1998-01-01

The effects of dietary alpha-tocopherol supplementation and gamma-irradiation on alpha-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg alpha-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0 kGy. Cooked irradiated and unirradiated meat was stored at 4 degrees C for 5 days. alpha-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary alpha-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg alpha-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg alpha-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in alpha-tocopherol-supplemented meat following cooking and storage

UVA Irradiation of Dysplastic Keratinocytes: Oxidative Damage versus Antioxidant Defense

Science.gov (United States)

Nechifor, Marina T.; Niculiţe, Cristina M.; Urs, Andreea O.; Regalia, Teodor; Mocanu, Mihaela; Popescu, Alexandra; Manda, Gina; Dinu, Diana; Leabu, Mircea

2012-01-01

UVA affects epidermal cell physiology in a complex manner, but the harmful effects have been studied mainly in terms of DNA damage, mutagenesis and carcinogenesis. We investigated UVA effects on membrane integrity and antioxidant defense of dysplastic keratinocytes after one and two hours of irradiation, both immediately after exposure, and 24 h post-irradiation. To determine the UVA oxidative stress on cell membrane, lipid peroxidation was correlated with changes in fatty acid levels. Membrane permeability and integrity were assessed by propidium iodide staining and lactate dehydrogenase release. The effects on keratinocyte antioxidant protection were investigated in terms of catalase activity and expression. Lipid peroxidation increased in an exposure time-dependent manner. UVA exposure decreased the level of polyunsaturated fatty acids, which gradually returned to its initial value. Lactate dehydrogenase release showed a dramatic loss in membrane integrity after 2 h minimum of exposure. The cell ability to restore membrane permeability was noted at 24 h post-irradiation (for one hour exposure). Catalase activity decreased in an exposure time-dependent manner. UVA-irradiated dysplastic keratinocytes developed mechanisms leading to cell protection and survival, following a non-lethal exposure. The surviving cells gained an increased resistance to apoptosis, suggesting that their pre-malignant status harbors an abnormal ability to control their fate. PMID:23222638

Process for the radiation cross-linking of a tetra fluoroetylene-propylene copolymer. [electrons and gamma rays

Energy Technology Data Exchange (ETDEWEB)

Tabata, Y; Kojima, G

1971-12-30

A tetrafluoroethylene copolymer useful as a heat resistant rubber is cross-linked by a relatively low dose irradiation. The process comprises irradiating the copolymer with ionizing radiations in the presence of a radical initiator, for example peroxides and azo-compounds, or in the presence of an active oxygen-releasable oxidizing agent such as potassium dichromate. The gel content can be controlled between 10% and 50% or more. The molecular weight of the copolymer is preferred to be more than 20,000 for the purpose of making the rubber cross-linked. The quantity or promoter added may be 0.1 to 20%, preferably 0.2 to 10% by weight. The absorption dose may be 10/sup 3/ to 10/sup 8/ rad at a dose rate of 10/sup 2/ to 10/sup 9/ roentgen/hr, preferably 10/sup 3/ to 5 x 10/sup 7/ roentgen/hr. In examples, tetrafluoroethylene-propylene copolymer of molecular weight 30,000 and a molecular ratio of C/sub 2/F/sub 4/:C/sub 3/H/sub 6/=52:48 was mixed with the following promoters at 60/sup 0/C: BPO (benzoil peroxide), K/sub 2/Cr/sub 2/O/sub 7/, percumyl D, azo-bisbutyl nitrile and potassium permanganate. The mixture was hot rolled to form a sheet 1 mm thick. The sheets were exposed to electron beams from a 1.5 MV electron accelerator at a flux density of 0.48 uZ/cm/sup 2/. The test results with 6 Mrad were, for 0.2% BPO a gel content ratio of 22%, breaking strength of 65 kg/cm/sup 2/ and elongation 900%; for K/sub 2/Cr/sub 2/O/sub 7/, the gel content ratio was 42%, the breaking strength 85 kg/cm/sup 2/ and the elongation 600%; for 5% percumyl D, the gel content ratio was 45%, the breaking strength 95 kg/cm/sup 2/ and the elongation 500%.

Preparation of gold microparticles using halide ions in bulk block copolymer phases via photoreduction

International Nuclear Information System (INIS)

Cha, Sang-Ho; Kim, Ki-Hyun; Lee, Won-Ki; Lee, Jong-Chan

2009-01-01

Gold microparticles were prepared from the gold salt in the solid bulk phase of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer via a photoreduction process in the presence of halide ions. The shapes and sizes of the gold microparticles were found to be dependent on the types and amount of halide ions as well as the types of cations used due to the combined effects of the adsorption power and oxidative dissolution ability of the additives on gold surfaces. Gold nanorods were obtained when poly(ethylene oxide) was used instead of the block copolymer. This suggests that the poly(propylene oxide) (PPO) parts in the block copolymer are essential for the formation of gold microparticles, even though the degree of the direct interaction between the PPO blocks and gold salt is not significant. - Graphical abstract: Gold microparticles were successfully prepared using halide ions as additives in the polymeric bulk phase via photoreduction with the glow lamp irradiation.

XRD monitoring of α self-irradiation in uranium-americium mixed oxides.

Science.gov (United States)

Horlait, Denis; Lebreton, Florent; Roussel, Pascal; Delahaye, Thibaud

2013-12-16

The structural evolution under (241)Am self-irradiation of U(1-x)Am(x)O(2±δ) transmutation fuels (with x ≤ 0.5) was studied by X-ray diffraction (XRD). Samples first underwent a preliminary heat treatment performed under a reducing atmosphere (Ar/H2(4%)) aiming to recover the previously accumulated structural defects. Over all measurements (carried out over up to a full year and for integrated doses up to 1.5 × 10(18) α-decay events·g(-1)), only fluorite U(1-x)Am(x)O(2±δ) solid solutions were observed. Within a few days after the end of the heat treatment, each of the five studied samples was slowly oxidized as a consequence of their move to air atmosphere, which is evidenced by XRD by an initial sharp decrease of the unit cell parameter. For the compounds with x ≤ 0.15, this oxidation occurred without any phase transitions, but for U0.6Am0.4O(2±δ) and U0.5Am0.5O(2±δ), this process is accompanied by a transition from a first fluorite solid solution to a second oxidized one, as the latter is thermodynamically stable in ambient conditions. In the meantime and after the oxidation process, (241)Am α self-irradiation caused a structural swelling up to ∼0.8 vol %, independently of the sample composition. The kinetic constants of swelling were also determined by regression of experimental data and are, as expected, dependent on x and thus on the dose rate. The normalization of these kinetic constants by sample α-activity, however, leads to very close swelling rates among the samples. Finally, evolutions of microstrain and crystallite size were also monitored, but for the considered dose rates and cumulated doses, α self-irradiation was found, within the limits of the diffractometer used, to have almost no impact on these characteristics. Microstrain was found to be influenced instead by the americium content in the materials (i.e., by the impurities associated with americium starting material and the increase of cationic charge heterogeneity with

L-Arginine Increases Cytotoxicity in Irradiated Ehrlich Carcinoma Cell Line: Possible Potential Role of Nitric Oxide

International Nuclear Information System (INIS)

Noaman, E.

2008-01-01

Cancer cells possess nitric oxide syntheses (NOS) which metabolize L-Arginine (L-Arg) for producing nitric oxide (NO) The present study investigates the relations between NO and ionizing radiation in the Ehrlich ascites carcinoma (EAC) cell line. NOS activity was stimulated by exposure of cells to L-Arg just after irradiation. L-Arg (5 m M) supply led to an increase in ionizing radiation induced cytotoxicity (% of viability 18± 3 %) whereas, neither L-Arg itself nor ionizing irradiation caused cell death at the doses used in this study. Also, cells were treated either with L-Thio citrulline (L-Thio), an irreversible inhibitor of NOS or with exogenous superoxide dismutase (SOD) and catalase. L-Thio and SOD prevented L-Arg mediated deleterious effects on Irradiated cells, whereas catalase was ineffective. Intracellular antioxidant enzyme activity was also determined. Ionizing radiation + L-Arg stress altered the activity of catalase (66 % decrease) and glutathione peroxidase (83 % decrease). Our findings demonstrated that L-Arg induces increase the radiation-mediated deleterious effects in Ehrlich ascites carcinoma cells cytotoxicity and that the ratio NO/ O 2 plays a key role in these processes. NO could participate the deleterious effect of irradiation, in conjugation with others reactive oxygen species (ROS) produced during the oxidation of intracellular components by ionizing radiation (dose 6 Gy)

21 CFR 177.1980 - Vinyl chloride-propylene copolymers.

Science.gov (United States)

2010-04-01

... used as components of articles intended for contact with food, subject to the provisions of this... chlorine content is in the range of 53 to 56 percent as determined by any suitable analytical procedure of... section. (d) Analytical methods: The analytical methods for determining whether vinyl chloride-propylene...

Progress in Characterizing Thermal Degradation of Ethylene-Propylene Rubber

Energy Technology Data Exchange (ETDEWEB)

Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Qian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Childers, Matthew I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Correa, Miguel [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shin, Yongsoon [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zwoster, Andy [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-08-26

Ethylene-propylene rubber (EPR) is one of the two most common nuclear cable insulation materials. A large fraction of EPR-insulated cables in use in the nuclear industry were manufactured by The Okonite Company. Okoguard® is the name of the medium voltage thermoset EPR manufactured by The Okonite Company. Okoguard® has been produced with silane-treated clay filler and the characteristic pink color since the 1970’s. EPR is complex material that undergoes simultaneous reactions during thermal aging including oxidative and thermal cleavage and oxidative and thermal crosslinking. This reaction complexity makes precise EPR service life prediction from accelerated aging using approaches designed for single discreet reactions such as the Arrhenius approach problematic. Performance data and activation energies for EPR aged at conditions closer to service conditions will improve EPR lifetime prediction. In this report pink Okoguard® EPR insulation material has been thermally aged at elevated temperatures. A variety of characterization techniques have been employed to track material changes with aging. It was noted that EPR aged significant departure in aging behavior seemed to occur at accelerated aging temperatures between 140°C and 150°C at around 20 days of exposure. This may be due to alternative degradation mechanisms being accessed at this higher temperature and reinforces the need to perform accelerated aging for Okoguard® EPR service life prediction at temperatures below 150°C.

Oxygen consumption in EPDM irradiated under different oxygen pressures and at different LET

International Nuclear Information System (INIS)

Dely, N.; Ngono-Ravache, Y.; Ramillon, J.-M.; Balanzat, E.

2005-01-01

We conceived a novel set-up for measuring the radiochemical yields of oxygen consumption in polymers. The measurement is based on a sampling of the gas mixture with a mass spectrometer, before and after irradiation. We irradiated an ethylene, propylene and 1,4-hexadiene terpolymer (EPDM) with 1 MeV electron and 10.75 MeV/A carbon beams. Samples were irradiated under oxygen within a wide range of pressure (5-200 mbar). The yields under C irradiation are four times smaller than the yields under electron irradiation. This shows that radiooxidation is very sensitive to the linear energy transfer of the projectiles and hence to the heterogeneity of the energy deposition. The oxygen consumption yields do not vary significantly in the range of pressure investigated; even at 5 mbar, the kinetics is still governed by the bimolecular recombination of peroxy radicals

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

Energy Technology Data Exchange (ETDEWEB)

Singh, Hemant Kr. [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi (India); Avasthi, D.K. [Inter University Accelerator Center, Post Box 10502, New Delhi (India); Aggarwal, Shruti, E-mail: shruti.al@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi (India)

2015-06-15

Highlights: •The objective is to study the effect of swift heavy ion (SHI) irradiation on photoanode of DSSC for better efficiency. •This work presents the effect of SHI irradiation on various Transparent conducting oxides (TCOs). •Effects are studied in terms of conductivity and transmittance of TCOs. •ITO-PET gives best results in comparison to ITO and FTO for DSSC application under SHI irradiation. -- Abstract: Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO{sub 2}:F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In{sub 2}O{sub 3}:Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag{sup +9} ions at fluences ranging from 3.0 × 10{sup 11} ions/cm{sup 2} to 3.0 × 10{sup 13} ions/cm{sup 2}. The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications.

Effects of hydrogen and propylene presence on decomposition of hydrogen peroxide over palladium catalysts

NARCIS (Netherlands)

Chen, T.; Kertalli, E.; Nijhuis, T.A.; Podkolzin, S.

2016-01-01

Reaction rates for H2O2 decomposition in a methanol solution were measured over Pd/SiO2 catalysts in the presence of gas-phase N2, H2 and propylene. The H2O2 decomposition rates were higher in the presence of H2 and lower in the presence of propylene compared to those under N2, which acted as an

Prediction model for oxide thickness on aluminum alloy cladding during irradiation

International Nuclear Information System (INIS)

Kim, Yeon Soo; Hofman, G.L.; Hanan, N.A.; Snelgrove, J.L.

2003-01-01

An empirical model predicting the oxide film thickness on aluminum alloy cladding during irradiation has been developed as a function of irradiation time, temperature, heat flux, pH, and coolant flow rate. The existing models in the literature are neither consistent among themselves nor fit the measured data very well. They also lack versatility for various reactor situations such as a pH other than 5, high coolant flow rates, and fuel life longer than ∼1200 hrs. Particularly, they were not intended for use in irradiation situations. The newly developed model is applicable to these in-reactor situations as well as ex-reactor tests, and has a more accurate prediction capability. The new model demonstrated with consistent predictions to the measured data of UMUS and SIMONE fuel tests performed in the HFR, Petten, tests results from the ORR, and IRIS tests from the OSIRIS and to the data from the out-of-pile tests available in the literature as well. (author)

Evaluation of time-accelerated irradiation method of elastomer by modulus-ultimate elongation profile

International Nuclear Information System (INIS)

Ito, Masayuki; Oka, Toshitaka; Hama, Yosimasa

2009-01-01

'Generalized modulus-ultimate elongation profile' was induced from the relationship between the modulus and the ultimate elongation of an elastomer that was quantitatively added crosslinking and scission. This profile can be used to evaluate the time-accelerated irradiation methods of ethylene-propylene-diene elastomer. The irradiation under low dose rate (0.33 kGy/h) at room temperature was the reference condition. The short-time irradiation condition was 4.2 kGy/h in 0.5 MPa oxygen at room temperature and 5.0 kGy/h in air at 70 o C. The former tended to bring about the higher ratio of scission than the reference condition; the latter tended to bring about the higher ratio of crosslinking.

Behavior of high Tc-superconductors and irradiated defects under reactor irradiation

International Nuclear Information System (INIS)

Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru; Yoshida, Hiroyuki.

1991-01-01

It has been well known that the lattice defects of various types are introduced in ceramics without exception, and exert large effect to the function of these materials. Among oxides, the electronic materials positively using oxygen defect control have been already put in practical use. Also in the oxide high temperature superconductors which are Perovskite type composite oxides, the superconductive characteristics are affected largely by the concentration of the oxygen composing them. This is regarded as an important factor for causing superconductivity, related with the oxygen cavities arising at this time and the carriers bearing superconductivity. In this study, the irradiation effect with relatively low dose, the measurement under irradiation, the effect of irradiation temperature, and the effect of radiation quality were evaluated by the irradiation of YBCO, EBCO and LBCO. The experimental method, and the irradiation effect at low temperature and normal temperature, the effect of Co-60 gamma ray irradiation instead of reactor irradiation are reported. (K.I.)

Early life hormetic treatments decrease irradiation-induced oxidative damage, increase longevity, and enhance sexual performance during old age in the Caribbean fruit fly

International Nuclear Information System (INIS)

López-Martínez, Giancarlo; Hahn, Daniel A.

2014-01-01

Early life events can have dramatic consequences on performance later in life. Exposure to stressors at a young age affects development, the rate of aging, risk of disease, and overall lifespan. In spite of this, mild stress exposure early in life can have beneficial effects on performance later in life. These positive effects of mild stress are referred to as physiological conditioning hormesis. In our current study we used anoxia conditioning hormesis as a pretreatment to reduce oxidative stress and improve organismal performance, lifespan, and healthspan of Caribbean fruit flies. We used gamma irradiation to induce mild oxidative damage in a low-dose experiment, and massive oxidative damage in a separate high-dose experiment, in pharate adult fruit flies just prior to adult emergence. Irradiation-induced oxidative stress leads to reduced adult emergence, flight ability, mating performance, and lifespan. We used a hormetic approach, one hour of exposure to anoxia plus irradiation in anoxia, to lower post-irradiation oxidative damage. We have previously shown that this anoxic-conditioning treatment elevates total antioxidant capacity and lowers post-irradiation oxidative damage to lipids and proteins. In this study, conditioned flies had lower mortality rates and longer lifespan compared to those irradiated without hormetic conditioning. As a metric of healthspan, we tracked mating both at a young age (10 d) and old age (30 d). We found that anoxia-conditioned male flies were more competitive at young ages when compared to unconditioned irradiation stressed male flies, and that the positive effects of anoxic conditioning hormesis on mating success were even more pronounced in older males. Our data shows that physiological conditioning hormesis at a young age, not only improves immediate metrics of organismal performance (emergence, flight, mating), but the beneficial effects also carry into old age by reducing late life oxidative damage and improving lifespan and

Solid solutions of gadolinium doped zinc oxide nanorods by combined microwave-ultrasonic irradiation assisted crystallization

Science.gov (United States)

Kiani, Armin; Dastafkan, Kamran; Obeydavi, Ali; Rahimi, Mohammad

2017-12-01

Nanocrystalline solid solutions consisting of un-doped and gadolinium doped zinc oxide nanorods were fabricated by a modified sol-gel process utilizing combined ultrasonic-microwave irradiations. Polyvinylpyrrolidone, diethylene glycol, and triethylenetetramine respectively as capping, structure directing, and complexing agents were used under ultrasound dynamic aging and microwave heating to obtain crystalline nanorods. Crystalline phase monitoring, lattice parameters and variation, morphology and shape, elemental analysis, functional groups, reducibility, and the oxidation state of emerged species were examined by PXRD, FESEM, TEM, EDX, FTIR, micro Raman, H2-TPR, and EPR techniques. Results have verified that irradiation mechanism of gelation and crystallization reduces the reaction time, augments the crystal quality, and formation of hexagonal close pack structure of Wurtzite morphology. Besides, dissolution of gadolinium within host lattice involves lattice deformation, unit cell distortion, and angular position variation. Structure related shape and growth along with compositional purity were observed through microscopic and spectroscopic surveys. Furthermore, TPR and EPR studies elucidated more detailed behavior upon exposure to the exerted irradiations and subsequent air-annealing including the formed oxidation states and electron trapping centers, presence of gadolinium, zinc, and oxygen disarrays and defects, as well as alteration in the host unit cell via gadolinium addition.

A review of the irradiation evolution of dispersed oxide nanoparticles in the b.c.c. Fe-Cr system: Current understanding and future directions

Energy Technology Data Exchange (ETDEWEB)

Wharry, Janelle P., E-mail: jwharry@purdue.edu [Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States); Swenson, Matthew J.; Yano, Kayla H. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States)

2017-04-01

Thus far, a number of studies have investigated the irradiation evolution of oxide nanoparticles in b.c.c. Fe-Cr based oxide dispersion strengthened (ODS) alloys. But given the inconsistent experimental conditions, results have been widely variable and inconclusive. Crystal structure and chemistry changes differ from experiment to experiment, and the total nanoparticle volume fraction has been observed to both increase and decrease. Furthermore, there has not yet been a comprehensive review of the archival literature. In this paper, we summarize the existing studies on nanoparticle irradiation evolution. We note significant observations with respect to oxide nanoparticle crystallinity, composition, size, and number density. We discuss four possible contributing mechanisms for nanoparticle evolution: ballistic dissolution, Ostwald ripening, irradiation-enhanced diffusion, and homogeneous nucleation. Finally, we propose future directions to achieve a more comprehensive understanding of irradiation effects on oxide nanoparticles in ODS alloys.

Combined gas-phase oxidation of methane and ethylene

International Nuclear Information System (INIS)

Pogosyan, N.M.; Pogosyan, M.D.

2009-01-01

It is established that depending on the reaction conditions combined oxidation of methane and ethylene may result in ethylene and propylene oxides with high selectivity with respect to the process, where in the initial reaction mixture methane is replaced by the same quantity of nitrogen. The formed additional methyl radicals increase the yield of all reaction products except CO. At low temperatures methyl radicals react with oxygen resulting in methyl peroxide radicals, which in turn, reacting with ethylene provide its epoxidation and formation of other oxygen-containing products. At high temperatures as a result of addition reaction between methyl radicals and ethylene, propyl radicals are formed that, in turn yield propylene. Alongside with positive influence on the yield of reaction products, methane exerts negative influence upon the conversion, that is it decreases the rate of ethylene and oxygen conversion, simultaneously decreasing significantly the yield of CO

One-step synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Liu, Gang; Wang, Yujia; Pu, Xianjuan; Jiang, Yong; Cheng, Lingli, E-mail: chenglingli@shu.edu.cn; Jiao, Zheng, E-mail: zjiao@shu.edu.cn

2015-09-15

Graphical abstract: - Highlights: • Both graphene oxide and silver ion were reduced simultaneously by electron beam-based method. • The size of AgNPs can be controlled by changing the irradiation dose of electron beam. • The AgNPs/rGO nanocomposite exhibits much lower sheet resistivity (0.06 Ω m). - Abstract: A rapid, eco-friendly, one-step electron beam (EB)-based method for both the reduction of graphene oxide and loading of Ag nanoparticles (AgNPs) were achieved. Further, the effects of irradiation dose on the morphology of AgNPs and the sheet resistance of Ag nanoparticles/reduced graphene oxide (AgNPs/rGO) were studied. The results reveal that when the irradiation dose increased from 70 kGy to 350 kGy, the size of the AgNPs decreased and became uniformly distributed over the surface of the rGO nanosheets. However the size of the AgNPs increased when the irradiation dose reached 500 kGy. Four-point probe measurement showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistivity of 0.06 Ω m was obtained in the film corresponding to 350 kGy irradiation dose, which showed a much lower resistivity than the GO film (5.04 × 10{sup 5} Ω m). The formation mechanisms of the as-prepared AgNPs/rGO nanocomposites were proposed. This study provides a fast and eco-friendly EB irradiation induced method to controlling the dimensions of AgNPs/rGO nanocomposites, which can strongly support the mass production of AgNPs/rGO nanocomposites for practical applications.

One-step synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films by electron beam irradiation

International Nuclear Information System (INIS)

Liu, Gang; Wang, Yujia; Pu, Xianjuan; Jiang, Yong; Cheng, Lingli; Jiao, Zheng

2015-01-01

Graphical abstract: - Highlights: • Both graphene oxide and silver ion were reduced simultaneously by electron beam-based method. • The size of AgNPs can be controlled by changing the irradiation dose of electron beam. • The AgNPs/rGO nanocomposite exhibits much lower sheet resistivity (0.06 Ω m). - Abstract: A rapid, eco-friendly, one-step electron beam (EB)-based method for both the reduction of graphene oxide and loading of Ag nanoparticles (AgNPs) were achieved. Further, the effects of irradiation dose on the morphology of AgNPs and the sheet resistance of Ag nanoparticles/reduced graphene oxide (AgNPs/rGO) were studied. The results reveal that when the irradiation dose increased from 70 kGy to 350 kGy, the size of the AgNPs decreased and became uniformly distributed over the surface of the rGO nanosheets. However the size of the AgNPs increased when the irradiation dose reached 500 kGy. Four-point probe measurement showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistivity of 0.06 Ω m was obtained in the film corresponding to 350 kGy irradiation dose, which showed a much lower resistivity than the GO film (5.04 × 10 5 Ω m). The formation mechanisms of the as-prepared AgNPs/rGO nanocomposites were proposed. This study provides a fast and eco-friendly EB irradiation induced method to controlling the dimensions of AgNPs/rGO nanocomposites, which can strongly support the mass production of AgNPs/rGO nanocomposites for practical applications

Synchrotron X-ray irradiation effects on the device characteristics and the resistance to hot-carrier damage of MOSFETs with 4 nm thick gate oxides

International Nuclear Information System (INIS)

Tanaka, Yuusuke; Tanabe, Akira; Suzuki, Katsumi

1998-01-01

The effects of synchrotron x-ray irradiation on the device characteristics and hot-carrier resistance of n- and p-channel metal oxide semiconductor field effect transistors (MOSFETs) with 4 nm thick gate oxides are investigated. In p-channel MOSFETs, device characteristics were significantly affected by the x-ray irradiation but completely recovered after annealing, while the device characteristics in n-channel MOSFETs were not noticeably affected by the irradiation. This difference appears to be due to a difference in interface-state generation. In p-channel MOSFETs, defects caused by boron-ion penetration through the gate oxides may be sensitive to x-ray irradiation, causing the generation of many interface states. These interface states are completely eliminated after annealing in hydrogen gas. The effects of irradiation on the resistance to hot-carrier degradation in annealed 4 nm thick gate-oxide MOSFETs were negligible even at an x-ray dose of 6,000 mJ/cm 2

The influence of antioxidant and post-synthetic treatment on the properties of biodegradable poly(butylene succinates modified with poly(propylene oxide

Directory of Open Access Journals (Sweden)

DRAGANA PEPIC

2007-12-01

Full Text Available Novel poly(ester–ethers based on poly(butylene succinate (PBS as the hard segments and 30 mass % of poly(propylene oxide (PPO as the soft segments were synthesized with varying amount of the antioxidant (N,N'-diphenyl-p-phenylenediamine, DPPD. The influences of the addition of DPPD and the impact of post-synthetic treatment by precipitation on the molecular structure, thermal and physical properties, as well as on the storage stability of the biodegradable aliphatic copolyesters, were investigated. The structure and composition of the copolymers were determined by means of 1H-NMR spectroscopy. The molecular weight and polydispersity of the poly(ester–ethers were evaluated from solution viscosity and GPC measurements. The thermal properties and stability were evaluated, respecttively, by means of DSC and non-isothermal thermogravimetry in an inert nitrogen atmosphere. The biodegradability potential of the polymers was studied in hydrolytic and enzymatic degradation tests with Candida cylindracea lipase by monitoring the weight loss of polymer films after incubation. The weight losses of the samples increased with time and were in the range from 1 to 5 mass % after 4 weeks. GPC analysis confirmed that there were changes in the molecular weight of the copolyesters during both hydrolytic and enzymatic degradation tests, leading to the conclusion that the degradation mechanism of poly(butylenes succinate modified with PPO occurred through surface erosion and bulk degradation.

Modification of the properties of NBR/EPDM blends vulcanized by gamma irradiation

International Nuclear Information System (INIS)

Abou Zeid, M.M.; Shaltout, N.A.; Mohamed, M.A.; El Miligy, A.A.

2001-01-01

Blends of nitrile-butadiene rubber, NBR with ethylene propylene diene monomer EPDM rubber with varying contents have been prepared. Unloaded or loaded blends with 40 phr of HAF carbon black have been vulcanized by using gamma irradiation. Mechanical properties, namely tensile strength, tensile modulus and elongation at break have been followed up as a function of irradiation dose as well as blend component compositions. Moreover, the susceptibility of prepared composites towards organic solvents and car oils has been followed up in terms of swelling number and soluble fraction measurements. The organic solvents used are toluene and dimethyl-formamide and oil are car lubricating and brake oils. The results indicated improvements in mechanical properties of blend composites with irradiation dose and increased content NBR in the blend. Also, susceptibility to fluids decreased appreciably with irradiation dose but with different extents for different fluids

Electron microscope study of irradiated beryllium oxide; Etude au microscope electronique de l'oxyde de beryllium irradie

Energy Technology Data Exchange (ETDEWEB)

Bisson, A A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. {alpha}) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10{sup 19}, 9 x 10{sup 19} and 2 x 10{sup 20} n{sub f} cm{sup -2} at a temperature below 100 deg. C. For the irradiation at 6 x 10{sup 19} n{sub f} cm{sup -2}, the defects are merely visible, but at 2 x l0{sup 20} n{sub f} cm{sup -2} the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [French] L'oxyde de beryllium est d'abord etudie, par une methode fractographique, avant et apres irradiation, en

Polymeric membranes containing silver salts for propylene/propane separation

Directory of Open Access Journals (Sweden)

L. D. Pollo

2012-06-01

Full Text Available The separation of olefin/paraffin mixtures is one of the most important processes of the chemical industry. This separation is typically carried out by distillation, which is an energy and capital intensive process. One promising alternative is the use of facilitated transport membranes, which contain specific carrier agents in the polymer matrix that interact reversibly with the double bond in the olefin molecule, promoting the simultaneous increase of its permeability and selectivity. In this study, polyurethane (PU membranes were prepared using two different silver salts (triflate and hexafluorantimonate. The membranes were structurally characterized and their performance for the separation of propylene/propane mixtures was evaluated. The results of the characterization analyses indicated that the triflate salt was the most efficient carrier agent. The membranes containing this salt showed the best performance, reaching an ideal selectivity of 10 and propylene permeability of 188 Barrer.

Effect of Artocarpus communis Extract on UVB Irradiation-Induced Oxidative Stress and Inflammation in Hairless Mice

Directory of Open Access Journals (Sweden)

Feng-Lin Yen

2013-02-01

Full Text Available Administration of antioxidants and anti-inflammatory agents is an effective strategy for preventing ultraviolet (UV irradiation-induced skin damage. Artocarpus communis possesses several pharmacological activities, such as antioxidant, anticancer and anti-inflammation. However, the photoprotective activity of methanol extract of A. communis heartwood (ACM in ultraviolet irradiation-induced skin damage has not yet been investigated. The present study was performed using ultraviolet absorption, histopathological observation, antioxidant and anti-inflammation assays to elucidate the mechanism of the photoprotective activity of ACM. Our results indicated that ACM displayed a UVA and UVB absorption effect and then effectively decreased scaly skin, epidermis thickness and sunburn cells during ultraviolet irradiation in hairless mice. ACM not only decreased ultraviolet irradiation-mediated oxidative stress, including lowering the overproduction of reactive oxygen species and lipid peroxidation (p < 0.05, but also reduced the levels of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α and interleukin 1β. Additionally, ACM can decrease the synthesis of cytosolic phospholipase A2, cyclooxygenase, inducible nitric oxide synthase and vascular cell adhesion molecular-1 via inhibiting TNF-α-independent pathways (p < 0.05 in UVB-mediated inflammation and formation of sunburn cells. Consequently, we concluded that ACM extract has a photoprotective effect against UVB-induced oxidative stress and inflammation due to its sunscreen property, and its topical formulations may be developed as therapeutic and/or cosmetic products in further studies.

Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

International Nuclear Information System (INIS)

Schacht, L.; Navarrete, J.; Schacht, P.; Ramirez, M. A.

2010-01-01

V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

Energy Technology Data Exchange (ETDEWEB)

Schacht, L. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ciencia de Materiales, Av. IPN s/n, Edificio 9, Col. Lindavista, 07738 Mexico D. F. (Mexico); Navarrete, J.; Schacht, P.; Ramirez, M. A., E-mail: pschacha@imp.m [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D. F. (Mexico)

2010-07-01

V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

Irradiation effects of the zirconium oxidation and the uranium diffusion in zirconia; Effets d'irradiation sur l'oxydation du zirconium et la diffusion de l'uranium dans la zircone

Energy Technology Data Exchange (ETDEWEB)

Bererd, N

2003-07-01

The context of this study is the direct storage of spent fuel assemblies after operation in reactor. In order to obtain data on the capacities of the can as the uranium diffusion barrier, a fundamental study has been carried out for modelling the internal cladding surface under and without irradiation. The behaviour of zirconium in reactor conditions has at first been studied. A thin uranium target enriched with fissile isotope has been put on a zirconium sample, the set being irradiated by a thermal neutrons flux leading to the fission of the deposited uranium. The energetic history of the formed fission products has revealed two steps: 1)the zirconium oxidation and 2)the diffusion of uranium in the zirconia formed at 480 degrees C. A diffusion coefficient under irradiation has been measured. Its value is 10{sup -15} cm{sup 2}.s{sup -1}. In order to be able to reveal clearly the effect of the irradiation by the fission products on the zirconium oxidation, measurements of thermal oxidation and under {sup 129}Xe irradiation have been carried out. They have shown that the oxidation is strongly accelerated by the irradiation and that the temperature is negligible until 480 degrees C. On the other hand, the thermal diffusion of the uranium in zirconium and in zirconia has been studied by coupling ion implantation and Rutherford backscattering spectroscopy. This study shows that the uranium diffuses in zirconium and is trapped in zirconia in a UO{sub 3} shape. (O.M.)

Aging of magnesium stearate under high doses gamma irradiation and oxidative conditions

Energy Technology Data Exchange (ETDEWEB)

Lebeau, D.; Beuvier, L.; Cornaton, M. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Tabarant, M. [CEA, DEN, DPC, SEARS, LISL, F-91191 Gif-sur-Yvette (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France)

2015-05-15

Highlights: • Magnesium stearate was radio-oxidized at very high doses using gamma-rays. • H{sub 2} emission was estimated as a function of the integrated dose. • Modifications in the organic solid were followed as a function of the integrated dose. • A non-exhaustive degradation mechanism of magnesium stearate was proposed. - Abstract: In nuclear waste packages conditioning processes, magnesium stearate is widely used because of its high lubricating properties. For safety purposes, the radiolytic degradation of these organic materials has to be better understood to be able to predict their aging in repository conditions. This study reports the radiolytic degradation of magnesium stearate, using gamma-rays at room temperature and under air. Modifications were followed using different analytical tools (XPS, ATR-FTIR, ICP-AES, ATG and mass spectrometry). It has been observed that molecules mainly formed up to 1000 kGy of gamma irradiation dose under radio-oxidation are alkanes, hydroperoxides, double bonds in the aliphatic chain, carboxylates with aliphatic chain shorter than the one of stearate and ketones. At a dose of 4000 kGy, dicarboxylic acids are observed: the formation of these molecules needs a dose of at least 1000 kGy to be created under radio-oxidation. These observations allow us to propose a non-exhaustive degradation mechanism of magnesium stearate under gamma-irradiation at room temperature and under air.

Suppressing propylene carbonate decomposition by coating graphite electrode foil with silver

International Nuclear Information System (INIS)

Gao, J.; Zhang, H.P.; Fu, L.J.; Zhang, T.; Wu, Y.P.; Takamura, T.; Wu, H.Q.; Holze, R.

2007-01-01

A method has been developed to suppress the decomposition of propylene carbonate (PC) by coating graphite electrode foil with a layer of silver. Results from electrochemical impedance measurements show that the Ag-coated graphite electrode presents lower charge transfer resistance and faster diffusion of lithium ions in comparison with the virginal one. Cyclic voltammograms and discharge-charge measurements suggest that the decomposition of propylene carbonate and co-intercalation of solvated lithium ions are prevented, and lithium ions can reversibly intercalate into and deintercalate from the Ag-coated graphite electrode. These results indicate that Ag-coating is a good way to improve the electrochemical performance of graphitic carbon in PC-based electrolyte solutions

Microwave-irradiation polyol synthesis of PVP-protected Pt–Ni electrocatalysts for methanol oxidation reaction

CSIR Research Space (South Africa)

Mathe, Ntombizodwa R

2017-01-01

Full Text Available ://doi.org/10.1007/s12678-017-0441-3 Microwave-Irradiation Polyol Synthesis of PVP-Protected Pt–Ni Electrocatalysts for Methanol Oxidation Reaction Ntombizodwa R. Mathe Manfred R. Scriba Rirhandzu S. Rikhotso Neil J. Coville ABSTRACT: Bimetallic Pt...

Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

Science.gov (United States)

Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

2015-07-01

In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

Coulometric titrations of bases in propylene carbonate and g-butyrolactone using hydroquinone as the depolarizer and a quinhydrone indicator electrode

Directory of Open Access Journals (Sweden)

Z. D. STANIC

2000-08-01

Full Text Available The application of hydroquinone for the coulometric generation of hydrogen ions in propylene carbonate (PC and g-butyrolactone (GBL is described. The current-potential curves recorded for theid sepolarizer, titrated bases, indicator and the solvents used showed that the investigated depolarizer is oxidized at lower potentials than the oxidation potentials of other components in the solution. the hydrogen ions generated by the oxidation of hydroquinone were used for the titration of organic bases (triethylamine, n-butylamine, pyridine, quinoline, aniline, N,N’-diphenylguanidine, piperidine, and 2,2’-bipiridine in PC and GBL with visual (Crystal Violet as indicator and potentiometric end-point detection using a quinhydrone electrode as the indicator electrode. The quinhydrone added to the to be analyzed solution served both as a source of hydrogen ions and, together with the immersed platinum electrode, as a quinhydrone electrode. The relative error of the determination of the bases was about 1 %.

Using of Coffee and Cardamom Mixture to Ameliorate Oxidative Stress Induced in irradiated Rats

International Nuclear Information System (INIS)

Hamza, R.G.; Osman, N.N.

2013-01-01

Human exposure to ionizing radiation induced overproduction of free radicals leading to oxidative stress. This study aimed to evaluate the possibility of using of coffee and cardamom mixture; as natural antioxidant compounds ; to ameliorate oxidative stress in rats induced by exposure to ionizing radiation. Phenolic contents in coffee and essential oils in cardamom were identified by using HPLC chromatography and GC/MS analysis. Four groups of adult male rats were used; the control group (A), the second group (B) received orally the mixture extract of coffee and cardamom (60 mg/100g body weight) for 8 weeks, the third group (C) irradiated (6 Gy) and the fourth group (D) received orally the mixture extract for 8 weeks and exposed to radiation at the 4th week. The results revealed that the administration of mixture extract of coffee and cardamom to rats significantly reduced the damage effect induced by irradiation via the adjustment of the antioxidant status, decreasing of malondialdehyde content and the subsequent amending of different biochemical parameters as well as some hormones. Accordingly, it is possible to indicate that coffee-cardamom reduced the radiation exposure induced oxidative stress.

Rotational dynamics of propylene inside Na-Y zeolite cages

Indian Academy of Sciences (India)

We report here the quasielastic neutron scattering (QENS) studies on the dynamics of propylene inside Na-Y zeolite using triple axis spectrometer (TAS) at Dhruva reactor, Trombay. Molecular dynamics (MD) simulations performed on the system had shown that the rotational motion involves energy larger than that involved ...

Shark Cartilage Attenuates Oxidative Stress in the liver of Guinea Pigs Exposed to Carbon Tetrachloride and/or Gamma Irradiation

International Nuclear Information System (INIS)

Ibrahim, N.K.; Abd El Aziz, N.

2009-01-01

There is overwhelming evidence to indicate that oxidative stress is involved in the pathogenesis of several diseases. Carbon tetrachloride (CCl 4 ) and ionizing radiations are environmental pollutants well known to induce free radicals formation and oxidative stress. The objective of this work was to evaluate the effect of shark cartilage administration on CCl 4 and/or gamma radiation-induced oxidative damage in the liver. CCl 4 (1 ml/kg body wt) was subcutaneously administered to guinea pigs twice a week for four weeks. Gamma irradiation (RAD) was applied by whole body exposure of guinea pigs to 1.0 Gy/week up to a total dose of 4.0 Gy. Shark cartilage (ShC) was given to animals at a concentration of 1.0 g/kg body wt daily, one week before exposure to CCl 4 and/or gamma irradiation and during the experimental period. Animals sacrificed at the end of the experimental period showed that administration of shark cartilage has significantly attenuated the increase in liver malonaldehyde (MDA) observed in CCl 4 and/or irradiated guinea pigs. Furthermore, shark cartilage treatment has significantly increased the activity of antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) and the content of reduced glutathione (GSH). The amelioration of oxidative stress induced in liver tissues of CCL 4 and/or irradiated guinea pigs treated with shark cartilage was associated with significant improvement in the activity of serum alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), as well as, bilirubin, albumin, and iron contents. It could be concluded that shark cartilage might protect liver tissues from oxidative injury induced by environmental pro-oxidants pollutants via modulating the antioxidant status and decreasing the process of lipid peroxidation

Studies on the formation of volatile amines from trimethylamine oxide by gamma-irradiation, (1)

International Nuclear Information System (INIS)

Uchiyama, Sadao; Kondo, Tatsuo; Uchiyama, Mitsuru

1976-01-01

The fundamental investigation concerning the formation of volatile amines from trimethylamine oxide (TMAO) by gamma-irradiation was carried out as a model of the irradiation of fish-meat products like Kamaboko. By the irradiation of 5.8 Mrad, 5 x 10 -6 mol of dimethylamine (DMA) was produced from 1 x 10 -4 mol of TMAO in a phosphate buffer (pH 6.5). Fe 2+ , Fe 3+ , Zn 2+ and Al 3+ promoted the formation of amines but Ca 2+ , Mg 2+ and Na + scarcely affected it. On the other hand, cysteine, which is known as a protecting agent against gamma-ray, promoted the formation of DMA. However, protain worked repressibly for amine formation even when Fe 3+ was contained. (auth.)

Development of ionization effects on oxidative stability of spices and its enhancement in the detection of irradiated foods

International Nuclear Information System (INIS)

Mekni, Mouna

2010-01-01

Physico-chemical properties and anti oxidative stability were released on extracts from untreated (non irradiated) caraway (carum carvi) and oregano leaves (origanum vulgare) samples, as well as from those γ irradiated by Co 6 0 source at doses from 0,5 to 15 kGy were studied by EPR and UV-Vis Spectroscopy, and expressed as DPPH radical scavenging ability, antioxidant index which was determined by β carotene/linoleic acid co-oxidation and total phenolic compounds content (TPC) of each extract were characterized. Respecting the fact that the application of γ radiation on spices leads to the production of paramagnetic species, character of radicals formed upon γ irradiation in solid phase was studied by mean of EPR spectroscopy and the stability of the obtained EPR signal of irradiated samples was studied over a storage period of 3 months. Irradiation was found to nonsignificantly increase and/or maintain all antioxidant parameters, TPC and the EPR signal intensity was found to be increased in studied spices with the radiation doses. The EPR measurements performed during storage period after radiation process showed a significant decrease of free radicals signal intensity until their stability.

Effect of electron beam irradiation on the properties of crosslinked rubbers

Science.gov (United States)

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.

DT fusion neutron irradiation of ORNL magnesium oxide crystals and BNL--LASL superconductor wires

International Nuclear Information System (INIS)

MacLean, S.C.

1978-01-01

The DT fusion neutron irradiation of two ORNL magnesium oxide crystals and eleven BNL-LASL superconductor wires is described. The sample position and neutron dose record are given. The maximum neutron fluence on any sample was 2.16 x 10 16 neutrons/cm 2

Structural and optical studies of 100 MeV Au irradiated thin films of tin oxide

Science.gov (United States)

Jaiswal, Manoj Kumar; Kanjilal, D.; Kumar, Rajesh

2013-11-01

Thin films of tin(IV) oxide (SnO2) of 100 nm thickness were grown on silicon (1 0 0) matrices by electron beam evaporation deposition technique under high vacuum. The thicknesses of these films were monitored by piezo-sensor attached to the deposition chamber. Nanocrystallinity is achieved in these thin films by 100 MeV Au8+ using 1 pnA current at normal incidence with ion fluences varying from 1 × 1011 ions/cm2 to 5 × 1013 ions/cm2. Swift Heavy Ion beam irradiation was carried out by using 15 UD Pelletron Accelerator at IUAC, New Delhi, India. Optical studies of pristine and ion irradiated thin films were characterized by UV-Visible spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Prominent peak at 610 cm-1 in FTIR spectrum confirmed the O-Sn-O bonding of tin(IV) oxide. For Surface topographical studies and grain size calculations, these films were characterized by Atomic Force Microscope (AFM) using Nanoscope III-A. Crystallinity and phase transformation due to irradiation of pristine and irradiated films were characterized by Glancing Angle X-ray Diffraction (GAXRD) using Brucker-D8 advance model. GAXRD results show improvement in crystallinity and phase transformation due to swift heavy ion irradiation. Grain size distribution was verified by AFM and GAXRD results. Swift heavy ion induced modifications in thin films of SnO2 were confirmed by the presence of prominent peaks at 2θ values of 30.65°, 32.045°, 43.94°, 44.96° and 52.36° in GAXRD spectrum.

Investigations of fuel cladding chemical interaction in irradiated LMFBR type oxide fuel pins

International Nuclear Information System (INIS)

Roake, W.E.; Adamson, M.G.; Hilbert, R.F.; Langer, S.

1977-01-01

Understanding and controlling the chemical attack of fuel pin cladding by fuel and fission products are major objectives of the U.S. LMFBR Mixed Oxide Irradiation Testing Program. Fuel-cladding chemical interaction (FCCI) has been recognized as an important factor in the ability to achieve goal peak burnups of 8% (80.MWd/kg) in FFTF and in excess of 10% (100.MWd/kg) in the LMFBR demonstration reactors while maintaining coolant bulk outlet temperatures up to ∼60 deg. C (1100 deg. F). In this paper we review pertinent parts of the irradiation program and describe recent observation of FCCI in the fuel pins of this program. One goal of the FCCI investigations is to obtain a sufficiently quantitative understanding of FCCI such that correlations can be developed relating loss of effective cladding thickness to irradiation and fuel pin fabrication parameters. Wastage correlations being developed using different approaches are discussed. Much of the early data on FCCI obtained in the U.S. Mixed Oxide Fuel Program came from capsule tests irradiated in both fast and thermal flux facilities. The fast flux irradiated encapsulated fuel pins continue to provide valuable data and insight into FCCI. Currently, however, bare pins with prototypic fuels and cladding irradiated in the fast flux Experimental Breeder Reactor-II (EBR-II) as multiple pin assemblies under prototypic powers, temperatures and thermal gradients are providing growing quantities of data on FCCI characteristics and cladding thickness losses from FCCI. A few special encapsulated fuel pin tests are being conducted in the General Electric Test Reactor (GETR) and EBR-II, but these are aimed at providing specific information under irradiation conditions not achievable in the fast flux bare pin assemblies or because EBR-II Operation or Safety requirements dictate that the pins be encapsulated. The discussion in this paper is limited to fast flux irradiation test results from encapsulated pins and multiple pin

Investigations of fuel cladding chemical interaction in irradiated LMFBR type oxide fuel pins

Energy Technology Data Exchange (ETDEWEB)

Roake, W E [Westinghouse-Hanford Co., Richland, WA (United States); Adamson, M G [General Electric Company, Vallecitos Nuclear Center, Pleasanton, CA (United States); Hilbert, R F; Langer, S

1977-04-01

Understanding and controlling the chemical attack of fuel pin cladding by fuel and fission products are major objectives of the U.S. LMFBR Mixed Oxide Irradiation Testing Program. Fuel-cladding chemical interaction (FCCI) has been recognized as an important factor in the ability to achieve goal peak burnups of 8% (80.MWd/kg) in FFTF and in excess of 10% (100.MWd/kg) in the LMFBR demonstration reactors while maintaining coolant bulk outlet temperatures up to {approx}60 deg. C (1100 deg. F). In this paper we review pertinent parts of the irradiation program and describe recent observation of FCCI in the fuel pins of this program. One goal of the FCCI investigations is to obtain a sufficiently quantitative understanding of FCCI such that correlations can be developed relating loss of effective cladding thickness to irradiation and fuel pin fabrication parameters. Wastage correlations being developed using different approaches are discussed. Much of the early data on FCCI obtained in the U.S. Mixed Oxide Fuel Program came from capsule tests irradiated in both fast and thermal flux facilities. The fast flux irradiated encapsulated fuel pins continue to provide valuable data and insight into FCCI. Currently, however, bare pins with prototypic fuels and cladding irradiated in the fast flux Experimental Breeder Reactor-II (EBR-II) as multiple pin assemblies under prototypic powers, temperatures and thermal gradients are providing growing quantities of data on FCCI characteristics and cladding thickness losses from FCCI. A few special encapsulated fuel pin tests are being conducted in the General Electric Test Reactor (GETR) and EBR-II, but these are aimed at providing specific information under irradiation conditions not achievable in the fast flux bare pin assemblies or because EBR-II Operation or Safety requirements dictate that the pins be encapsulated. The discussion in this paper is limited to fast flux irradiation test results from encapsulated pins and multiple pin

γ-Irradiation assisted synthesis of graphene oxide sheets supported Ag nanoparticles with single crystalline structure and parabolic distribution from interlamellar limitation

Energy Technology Data Exchange (ETDEWEB)

Yue, Yunhao; Zhou, Baoming; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei, E-mail: xuzhiwei@tjpu.edu.cn; Liu, Liangsen; Kuang, Liyun; Ma, Meijun; Fu, Hongjun

2017-05-01

Highlights: • Graphene oxide sheets supported Ag nanoparticles composites are successfully prepared via γ-irradiation without surfactant or functional agent. • Ag nanoparticles exhibit single crystalline structure and parabolic distribution on the surface of graphene oxide sheets. • Proposing a view that the growth of intercellular AgNPs can be limited by graphite oxide. - Abstract: This paper reported a method to fabricate graphene oxide sheets supported Ag nanoparticles (AgNPs/GOS) with single crystalline structure and parabolic distribution without surfactant or functional agent. We used imidazole silver nitrate as intercalation precursor into the layers of graphite oxide, and subsequently reduction and growth of interlamellar AgNPs were induced via γ-irradiation. The results illustrated that the synergism of interlamellar limitation of graphite oxide and fragmentation ability of γ-irradiation could prevent coalescent reaction of AgNPs with other oligomeric clusters, and the single crystalline and small-sized (below 13.9 nm) AgNPs were prepared. Moreover, the content and size of AgNPs exhibited parabolic distribution on GOS surface because the graphite oxide exfoliated to GOS from the edge to the central area of layers. In addition, complete exfoliation degree of GOS and large-sized AgNPs were obtained simultaneously under suitable silver ions concentration. Optimized composites exhibited outstanding surface-enhanced Raman scattering properties for crystal violet with enhancement factor of 1.3 × 10{sup 6} and detection limit of 1.0 × 10{sup −7} M, indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules. Therefore, this study presented a strategy for developing GOS supported nanometal with single crystalline structure and parabolic distribution based on γ-irradiation.

γ-Irradiation assisted synthesis of graphene oxide sheets supported Ag nanoparticles with single crystalline structure and parabolic distribution from interlamellar limitation

International Nuclear Information System (INIS)

Yue, Yunhao; Zhou, Baoming; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei; Liu, Liangsen; Kuang, Liyun; Ma, Meijun; Fu, Hongjun

2017-01-01

Highlights: • Graphene oxide sheets supported Ag nanoparticles composites are successfully prepared via γ-irradiation without surfactant or functional agent. • Ag nanoparticles exhibit single crystalline structure and parabolic distribution on the surface of graphene oxide sheets. • Proposing a view that the growth of intercellular AgNPs can be limited by graphite oxide. - Abstract: This paper reported a method to fabricate graphene oxide sheets supported Ag nanoparticles (AgNPs/GOS) with single crystalline structure and parabolic distribution without surfactant or functional agent. We used imidazole silver nitrate as intercalation precursor into the layers of graphite oxide, and subsequently reduction and growth of interlamellar AgNPs were induced via γ-irradiation. The results illustrated that the synergism of interlamellar limitation of graphite oxide and fragmentation ability of γ-irradiation could prevent coalescent reaction of AgNPs with other oligomeric clusters, and the single crystalline and small-sized (below 13.9 nm) AgNPs were prepared. Moreover, the content and size of AgNPs exhibited parabolic distribution on GOS surface because the graphite oxide exfoliated to GOS from the edge to the central area of layers. In addition, complete exfoliation degree of GOS and large-sized AgNPs were obtained simultaneously under suitable silver ions concentration. Optimized composites exhibited outstanding surface-enhanced Raman scattering properties for crystal violet with enhancement factor of 1.3 × 10"6 and detection limit of 1.0 × 10"−"7 M, indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules. Therefore, this study presented a strategy for developing GOS supported nanometal with single crystalline structure and parabolic distribution based on γ-irradiation.

Separation of effects of oxide-trapped charge and interface-trapped charge on mobility in irradiated power MOSFETs

International Nuclear Information System (INIS)

Zupac, D.; Galloway, K.F.; Khosropour, P.; Anderson, S.R.; Schrimpf, R.D.

1993-01-01

An effective approach to separating the effects of oxide-trapped charge and interface-trapped charge on mobility degradation in irradiated MOSFETs is demonstrated. It is based on analyzing mobility data sets which have different functional relationships between the radiation-induced-oxide-trapped charge and interface-trapped charge. Separation of effects of oxide-trapped charge and interface-trapped charge is possible only if these two trapped charge components are not linearly dependent. A significant contribution of oxide-trapped charge to mobility degradation is demonstrated and quantified

Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species

International Nuclear Information System (INIS)

Allen, Brett L; Johnson, Jermaine D; Walker, Jeremy P

2012-01-01

In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase’s stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme’s exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a ‘sacrificial barrier’ by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase–PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO 2 (100 ppm). (paper)

The influence of oxidation on space charge formation in gamma-irradiated low-density polyethylene

CERN Document Server

Chen, G; Xie, H K; Banford, H M; Davies, A E

2003-01-01

The research presented in this paper investigates the role of oxidation in the formation of space charge in gamma-irradiated low-density polyethylene after being electrically stressed under dc voltage. Polyethylene plaques both with and without antioxidant were irradiated up to 500 kGy using a sup 6 sup 0 Co gamma source and space charge distributions were measured using the piezoelectric induced pressure wave propagation method. It has been found that a large amount of positive charge evolved adjacent to the cathode in the sample without antioxidant and was clearly associated with oxidation of the surface. The amount of charge formed for a given applied stress increased with the dose absorbed by the material. A model has been proposed to explain the formation of space charge and its profile. The charge decay after the removal of the external applied stress is dominated by a process being controlled by the cathode interfacial stress (charge injection) rather than a conventional RC circuit model. On the other ...

Thermoreversible covalent crosslinking of maleated ethylene/propylene copolymers with diols

NARCIS (Netherlands)

Mee, van der M.A.J.; Goossens, J.G.P.; Duin, van M.

2008-01-01

Maleated ethylene/propylene copolymer (MAn-g-EPM) was thermoreversibly cross-linked using different routes, i.e. ionic interactions (ionomers), hydrogen bonding and a combination thereof. Microphase separation into polar MAn-rich aggregates occurs for MAn-g-EPM and all cross-linked materials, which

Chemical states of fission products in irradiated uranium-plutonium mixed oxide fuel

International Nuclear Information System (INIS)

Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinsuke

1999-01-01

The chemical states of fission products (FPs) in irradiated uranium-plutonium mixed oxide (MOX) fuel for the light water reactor (LWR) were estimated by thermodynamic equilibrium calculations on system of fuel and FPs by using ChemSage program. A stoichiometric MOX containing 6.1 wt. percent PuO 2 was taken as a loading fuel. The variation of chemical states of FPs was calculated as a function of oxygen potential. Some pieces of information obtained by the calculation were compared with the results of the post-irradiation examination (PIE) of UO 2 fuel. It was confirmed that the multicomponent and multiphase thermodynamic equilibrium calculation between fuel and FPs system was an effective tool for understanding the behavior of FPs in fuel. (author)

Optical study of gamma irradiated sodium metaphosphate glasses containing divalent metal oxide MO (ZnO or CdO

Directory of Open Access Journals (Sweden)

E. Nabhan

Full Text Available Sodium metaphosphate glasses containing divalent metal oxide, ZnO or CdO with composition 50 P2O5 – (50 − x Na2O – x MO (ZnO, or CdO where x = 0, 10, 20 (mol% were prepared by conventional melt method. UV/visible spectroscopy and FTIR spectroscopy are measured before and after exposing to successive gamma irradiation doses (5–80 kGy. The optical absorption spectra results of the samples before irradiation reveal a strong UV absorption band at (∼230 nm which is related to unavoided iron impurities. The effects of gamma irradiation on the optical spectral properties of the various glasses have been compared. From the optical absorption spectral data, the optical band gap is evaluated. The main structural groups and the influence of both divalent metal oxide and gamma irradiation effect on the structural vibrational groups are realized through IR spectroscopy. The FTIR spectra of γ-irradiated samples are characterized by the stability of the number and position for the main characteristic band of phosphate groups. To better understood the structural changes during γ-irradiation, a deconvolution of FTIR spectra in the range 650–1450 cm−1 is made. The FTIR deconvolution results found evidence that, the changes occurring after gamma irradiation have been related to irradiation induced structural defects and compositional changes. Keywords: Sodium metaphosphate glass, UV–visible spectra, IR spectra, Deconvolution, Optical band gap, Gamma ray

Prenatal irradiation: nitric oxide and oxidative stress roles in radiation-induced apoptosis of the developing central nervous system

International Nuclear Information System (INIS)

Sanjurjo, Julieta

2001-01-01

Full text: The effects of prenatal irradiation on developing brain should be considered at cellular, structural and functional levels, integrating the information obtained from different sources in an appropriated model to explain the mechanisms involved in neuronal damage. That would permit to make risk estimations and improve radiological protection. Human brain is especially sensitive to ionizing radiation during certain stages of prenatal development. At doses such as those received by Hiroshima and Nagasaki's atomic bomb explosions survivors that were prenatally exposed, the maximum risk was to those exposed between the 8th and 15th weeks of gestation, in coincidence with the highest rate of neuron production and its migration to the brain cortex. The major effect produced on both, brain growth and development, was the augmentation of the Severe Mental Retardation (SMR) incidence. Radiation-induced apoptosis of neuronal progenitors should be considered as one of the factors associated with this pathology, apart from those of migration and synaptogenesis. Apoptosis is an innate and evolutionally conserved process by which the cells provoke the inactivation, disorganisation and degradation of their structural and functional components in a systematic fashion, with the aim of producing its own death. It is also the main cell death mechanism induced by low linear energy transfer (LET) ionizing radiation in developing Central Nervous System (CNS). Radioinduced apoptosis characterization during the different developmental stages, its kinetics and the possible implicated mechanisms (like oxidative injury and nitric oxide) was done using an 'in vitro' system of cortical micro masses (primary cultures of brain cortex cells) from rat embryo brains. Cell cultures were exposed to a single dose of gamma radiation, between 0,2 and 2 Gy, supplied by a Co 60 source (Picker C4M60) at a 70 cm distance with a field area size of 25 cm x 25 cm and at a 0,34 Gy/minute dose rate

Determination of melting point of mixed-oxide fuel irradiated in a fast breeder reactor

International Nuclear Information System (INIS)

Tachibana, Toshimichi

1985-01-01

The melting point of fuel is important to set its in-reactor maximum temperature in fuel design. The fuel melting point measuring methods are broadly the filament method and the capsule sealing method. The only instance of measuring the melting point of irradiated mixed oxide (U, Pu)O 2 fuel by the filament method is by GE in the United States. The capsule sealing method, while the excellent means, is difficult in weld sealing the irradiated fuel in a capsule within the cell. In the fast reactor development program, the remotely operated melting point measuring apparatus in capsule sealing the mixed (U, Pu)O 2 fuel irradiated in the experimental FBR Joyo was set in the cell and the melting point was measured, for the first time in the world. (Mori, K.)

High octane gasoline components from catalytic cracking gasoline, propylene, and isobutane by disproportionation, clevage and alkylation

Energy Technology Data Exchange (ETDEWEB)

Banks, R.

1980-07-08

A process is described for producing high octane value gasoline which comprises in a disproportionation zone subjecting propylene and a mixture of propylene and ethylene obtained as hereinafter delineated to disproportionation conditions to produce a stream containing ethylene and a stream containing butenes, passing the ethylene-containing stream from said disproportionation zone together with a catalytic cracking gasoline to a cleavage zone under disproportionation conditions and subjecting the mixture of hydrocarbons therin to cleavage to produce said mixture of propylene and ethylene, a C/sub 5//sup +/ gasoline-containing product and butenes and wherein the butenes obtained in the overall operation of the disproportionation zone and the cleavage zone are passed to an alkylation zone wherein said butenes are used to alkylate an isoparaffin to produce additional high octane value product.

The comparison of in vivo antigenotoxic and antioxidative capacity of two propylene glycol extracts of Calendula officinalis (marigold) and vitamin E in young growing pigs.

Science.gov (United States)

Frankic, T; Salobir, K; Salobir, J

2009-12-01

The objective of the study was to evaluate the protective effect of Calendula officinalis propylene glycol extracts against oxidative DNA damage and lipid peroxidation induced by high polyunsaturated fatty acid (PUFA) intake in young growing pigs. Forty young growing pigs were assigned to five treatment groups: control; oil (linseed oil supplementation); C. officinalis 1 and 2 groups (linseed oil plus 3 ml/day of C. officinalis propylene glycol extracts); and vitamin E group (linseed oil plus 100 mg/kg of vitamin E). Lymphocyte DNA fragmentation and 24-h urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) excretion were measured to determine DNA damage. Lipid peroxidation was studied by analysing plasma and urine malondialdehyde (MDA), and urine isoprostane concentrations (iPF2α-VI), total antioxidant status of plasma and glutathione peroxidase (GPx) assays. C. officinalis 1 (extract from petals) effectively protected DNA from oxidative damage. It indicated a numerical trend towards the reduction of plasma MDA and urinary iPF2α-VI excretion. Its effect was comparable with that of vitamin E. C. officinalis 2 (extract from flower tops) showed less antioxidant potential than the extract from petals. We can conclude that the amount of C. officinalis extracts proposed for internal use by traditional medicine protects the organism against DNA damage induced by high PUFA intake.

Crystal growth in EPDM by chemi-crystallisation as a function of the neutron irradiation dose and flux level

International Nuclear Information System (INIS)

Lambri, O.A.; Salvatierra, L.M.; Sanchez, F.A.; Matteo, C.L.; Sorichetti, P.A.; Celauro, C.A.

2005-01-01

Neutron irradiation at room temperature were performed on EPDM (ethylene-propylene-diene monomer) in two different nuclear reactors at different fluxes. The effect of the irradiation on the chain arrangement in the polymer, as a function of the dose is discussed. Different crystal concentrations and crystal shapes, developed by chemi-crystallisation, are obtained depending on the neutron dose. In addition the radiation damage degree in the polymer depends both on the dose and the flux level. Dynamical mechanical analysis, swelling studies, X-ray diffraction, differential thermal analysis and infrared studies were employed as experimental techniques

Investigation into the potential chemical mechanism of the pro-oxidant activity of carotenoids with liposomes under UV-irradiation

Directory of Open Access Journals (Sweden)

Cvetković Dragan J.

2017-01-01

Full Text Available This study focuses on the behavior of β-carotene and lutein inside multilamellar liposomes under continuous UV-irradiation. The liposomes were obtained by the thin film method and carotenoids (Crts were incorporated by mixing at various concentrations (0.005, 0.0075, 0.02, 0.07 and 0.5 mol %. Liposomes formation and the presence of Crts inside them were confirmed by SEM microscopy and FT-IR spectroscopy, respectively. The antioxidant/pro- -oxidant activity of Crts inside liposomes was determined by the thiobarbituric acid–malondialdehyde (TBA–MDA test. The investigated Crts acted more or less unexpected (as pro-oxidants inside the lipid bilayers, interacting with the UV-produced lipid radicals and simultaneously suffering under the UV-irradiation. Their pro-oxidant activity with liposomes and under UV-irradiation could be explained by the formation of unstable adducts in the reaction with peroxyl radicals, or by Crts-cation radicals formation via the electron transfer mechanism. Such tentatively unexpected behavior of carotenoids should be taken into consideration in further carotenoids-based UV-filters projections in cosmetic formulations for skin protection. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-34012

Effect of electron beam irradiation on the properties of crosslinked rubbers

Energy Technology Data Exchange (ETDEWEB)

Banik, Indranil; Bhowmick, Anil K. E-mail: anilkb@rtc.iitkgp.ernet.in

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 (T{sub g}) and storage modulus increased, while the elongation at the break and the loss tangent (tan {delta}){sub T{sub g}} decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

Effect of electron beam irradiation on the properties of crosslinked rubbers

International Nuclear Information System (INIS)

Banik, Indranil; Bhowmick, Anil K.

2000-01-01

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 (T g ) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) T g decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

Quantitative analysis of the gas evolved from high polymers in γ-irradiation

International Nuclear Information System (INIS)

Arakawa, Kazuo; Hayakawa, Naohiro; Kuriyama, Isamu

1977-09-01

Polymers are used as insulator of cables in nuclear-reactor radiation field. To estimate the evolution of gases when irradiated, total gas yield and composition were measured for variety of polymers. Samples were irradiated at room temperature in vacuo with 60 Co-γ rays. For ethylene propylene rubber (EPR), irradiation in high-temperature steam was also made. Composition of the gas was determined with a mass spectrometer. G-value of the total gaseous product was 3.2 to 3.4 for low-density polyethylene (LDPE) and 2.5 to 2.7 for high-density polyethylene (HDPE). In both polyethylene, hydrogen gas predominated. When an anti-radiation oil was added to LDPE, gas evolution was reduced drastically. For chloro-sulfonated PE (Hypalon), SO 2 gas was one of the major products even when the polymer contained only about 1% of sulfonyl groups. G-value of the total gas for EPR irradiated in high-temperature steam was 3.1, regardless of the temperature. (auth.)

Potentiometric chemical sensors from lignin-poly(propylene oxide) copolymers doped by carbon nanotubes.

Science.gov (United States)

Rudnitskaya, Alisa; Evtuguin, Dmitry V; Costa, Luis C; Graça, M Pedro F; Fernandes, António J S; Correia, M Rosario P; Gomes, M Teresa S R; Oliveira, J A B P

2013-01-21

Hardwood and softwood lignins obtained from industrial sulphite and kraft and laboratory oxygen-organosolv pulping processes were employed in co-polymerization with tolylene 2,4-diisocyanate terminated poly(propylene glycol). The obtained lignin-based polyurethanes were doped with 0.72 w/w% of multiwall carbon nanotubes (MWCNTs) with the aim of increasing their electrical conductivity to the levels suitable for sensor applications. Effects of the polymer doping with MWCNTs were assessed using electrical impedance (EIS) and UV-Resonance Raman (UV-RR) spectroscopy. Potentiometric sensors were prepared by drop casting of liquid polymer on the surface of carbon glass or platinum electrodes. Lignin-based sensors displayed a very low or no sensitivity to all alkali, alkali-earth and transition metal cations ions except Cr(VI) at pH 2. Response to Cr(VI) values of 39, 50 and 53 mV pX(-1) for the sensors based on kraft, organosolv and lignosulphonate lignins, respectively, were observed. Redox sensitivity values close to the theoretical values of 20 and 21 mV pX(-1) for organosolv and lignosulphonate based sensors respectively were detected in the Cr(III)/Cr(VI) solutions while a very low response was observed in the solutions containing Fe(CN)(6)(3-/4-). Conducting composite lignin-based polyurethanes doped with MWCNTs were suggested as being promising materials for Cr(VI)-sensitive potentiometric sensors.

Reduction of the number of germs in spices by radappertization

International Nuclear Information System (INIS)

Beczner, Laszlone; Kiss, Istvan

1983-01-01

The sterilization by fumigation with ethylene oxide and propylene oxide of ground paprika and spice mixtures used in preserves and meat industry was compared with the radappertization of the same spices. The number of germs including that of spores and moulds was determined. It can be established that irradiation with ionizing radiation (5 kGy) has the same effect on the reduction of the number of germs as sterilization by ethylene oxide. In addition, the side effects of sterilization can be avoided. (V.N.)

Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

KAUST Repository

Pan, Yichang; Li, Tao; Lestari, Gabriella; Lai, Zhiping

2012-01-01

The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed

Characteristics of the behavior of rare-earth oxides and composites on their base by charged particles and neutrons irradiated

International Nuclear Information System (INIS)

Tuseev, T.; Aksenova, T.I.; Berdauletov, A.K.

2000-01-01

In this work the results of comparative investigation of adsorption curves versus REM order number (La, Ce, Nd, Pr, Gd) and dose neutron irradiation are presented. It is discovered that the original REM oxides have high adsorption capacity both for donor gases and for acceptor ones. The adsorption capacity for oxygen and hydrogen becomes lower when the REM order number is higher, but it is contrary for water molecules. The obtained results showed that adsorption properties of REM oxides were changing on identical laws. But oxides of metals, having anomalous properties (variable valency, high cross-section capture) revealed especial adsorption properties under irradiation. In the time of consideration of possible mechanism of radiation - stimulated gas adsorption on oxide surface it is necessary to take in attention both the formation of radiation defects in crystal lattice and the characteristics of electron structure and presence of 4 f - cover in rare-earth metals

Building up Graphene-Based Conductive Polymer Composite Thin Films Using Reduced Graphene Oxide Prepared by γ-Ray Irradiation

Directory of Open Access Journals (Sweden)

Siyuan Xie

2013-01-01

Full Text Available In this paper, reduced graphene oxide (RGO was prepared by means of γ-ray irradiation of graphene oxide (GO in a water/ethanol mix solution, and we investigated the influence of reaction parameters, including ethanol concentration, absorbed dose, and dose rate during the irradiation. Due to the good dispersibility of the RGO in the mix solution, we built up flexible and conductive composite films based on the RGO and polymeric matrix through facile vacuum filtration and polymer coating. The electrical and optical properties of the obtained composite films were tested, showing good electrical conductivity with visible transmittance but strong ultraviolet absorbance.

Investigation of influence of radioactive irradiation on the microstructure of oxide dispersion strengthened steels

International Nuclear Information System (INIS)

Vlasenko, S.V.; Benediktovich, A.I.; Ul'yanenkova, T.A.; O’Konnell, Zh.; Nitling, I.

2015-01-01

The microstructure of unirradiated and irradiated samples of oxide dispersion strengthened (ODS) steels was investigated by X-ray diffraction in order to determine the influence of radiation on mechanical properties of steels. The microstructural parameters of ODS steels from measured diffraction profiles were evaluated using an approach where the complex oxide nanoparticles (Y 2 Ti 2 O 7 and Y 4 Al 2 O 9 ) are modeled as spherical inclusions in the steel matrix with coherent boundaries. The proposed method enables processing of diffraction data from materials containing spherical inclusions by treating them as one more source of peak broadening in addition to straight dislocations, and taking into account broadening due to crystallite size and instrumental effects. The microstructural parameters were obtained on the basis of fitting of experimental data by theoretical curve. The parameters of crystallite size distribution modeled by a lognormal distribution function (the median m and the variance σ), the strain anisotropy parameter q, the dislocation density, the dislocation arrangement parameter M, the density of oxide nanoparticles and the nanoparticle radius r 0 were determined for the ODS steel samples. It was established that irradiation has no significant influence on microstructure. The results obtained for physical parameters are in good agreement with the results of high-resolution transmission electron microscopy (HRTEM). (authors)

Structural and optical studies of 100 MeV Au irradiated thin films of tin oxide

Energy Technology Data Exchange (ETDEWEB)

Jaiswal, Manoj Kumar [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi 110 078 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Kumar, Rajesh, E-mail: rajeshkumaripu@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi 110 078 (India)

2013-11-01

Thin films of tin(IV) oxide (SnO{sub 2}) of 100 nm thickness were grown on silicon (1 0 0) matrices by electron beam evaporation deposition technique under high vacuum. The thicknesses of these films were monitored by piezo-sensor attached to the deposition chamber. Nanocrystallinity is achieved in these thin films by 100 MeV Au{sup 8+} using 1 pnA current at normal incidence with ion fluences varying from 1 × 10{sup 11} ions/cm{sup 2} to 5 × 10{sup 13} ions/cm{sup 2}. Swift Heavy Ion beam irradiation was carried out by using 15 UD Pelletron Accelerator at IUAC, New Delhi, India. Optical studies of pristine and ion irradiated thin films were characterized by UV–Visible spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Prominent peak at 610 cm{sup −1} in FTIR spectrum confirmed the O–Sn–O bonding of tin(IV) oxide. For Surface topographical studies and grain size calculations, these films were characterized by Atomic Force Microscope (AFM) using Nanoscope III-A. Crystallinity and phase transformation due to irradiation of pristine and irradiated films were characterized by Glancing Angle X-ray Diffraction (GAXRD) using Brucker-D8 advance model. GAXRD results show improvement in crystallinity and phase transformation due to swift heavy ion irradiation. Grain size distribution was verified by AFM and GAXRD results. Swift heavy ion induced modifications in thin films of SnO{sub 2} were confirmed by the presence of prominent peaks at 2θ values of 30.65°, 32.045°, 43.94°, 44.96° and 52.36° in GAXRD spectrum.

Irradiated accelerated corrosion of stainless steel

International Nuclear Information System (INIS)

Raiman, S.S.; Wang, P.; Was, G.S.

2015-01-01

Type 316L stainless steel was exposed to a simulated PWR environment with in-situ proton irradiation to investigate the effect of simultaneous irradiation and corrosion. To enable these experiments, a dedicated beamline was constructed to transport a 3.2 MeV proton beam from a tandem accelerator, through the sample that also acts as the window between the beamline vacuum and a corrosion cell designed to flow primary water at 320 C. degrees and 13.1 MPa. Experiments were conducted on 316L stainless steel samples which were irradiated for 24 hours in 320 C. degrees water with 3 ppm H 2 , at dose rates of 7*10 -6 dpa/s and 7*10 -7 dpa/s, for 4, 24, and 72 hours. A dual-layer oxide formed on the samples, with an inner layer rich in Cr with Fe and Ni content, and an outer layer of Fe oxides. Samples were characterized with TEM (Transmission Electron Microscopy), EDS, and Raman spectroscopy to determine the effect of irradiation. Irradiated samples were found to have a thinner and more porous inner oxide which was deficient in chromium. The outer oxide was found to have significant hematite content, suggesting that irradiation led to an increase in ECP (Electro-Chemical Potential) at the oxide-solution interface, causing accelerated dissolution of the oxide under irradiation. (authors)

Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene

International Nuclear Information System (INIS)

Novakovic, L.; Gal, O.; Markovic, V.; Stannett, V.T.

1985-01-01

In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author)

Molecular weight and its distribution of tetrafluoroethylene and propylene copolymer

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Okamoto, Jiro; Yamaguchi, Koichi.

1978-04-01

In comparison of molecular structure of tetrafluoroethylene and propylene copolymer produced by radiation and chemical initiators respectively, both were fractionated by elution method and fine structure was examined. For the fractionated sample by radiation, the relation between molecular weight anti Mn and intrinsic viscosity ( eta] is ( eta] = 3.97 x 10 -4 anti Mnsup(0.630) The result is not in agreement with that of the unfractionated sample by radiation, and similar to those of samples by chemical initiators. There is no difference, however, in the elution method of GPC between both these copolymers; the elution behavior agrees with that of standard polystyrene. Long chain branching thus exists little in the copolymer of tetrafluoroethylene and propylene. To reveal the relations between reaction conditions and molecular weight and its distribution of the copolymer produced by flow apparatus, the molecular weight distribution was measured by GPC. The method of analysis could evaluate molecular weight distribution changing constantly. (auth.)

Nonaqueous electrocatalytic water oxidation by a surface-bound Ru(bda)(L)₂ complex.

Science.gov (United States)

Sheridan, Matthew V; Sherman, Benjamin D; Wee, Kyung-Ryang; Marquard, Seth L; Gold, Alexander S; Meyer, Thomas J

2016-04-21

The rate of electrocatalytic water oxidation by the heterogeneous water oxidation catalyst [Ru(bda)(4-O(CH2)3P(O3H2)2-pyr)2], , (pyr = pyridine; bda = 2,2'-bipyridine-6,6'-dicarboxylate) on metal oxide surfaces is greatly enhanced relative to water as the solvent. In these experiments with propylene carbonate (PC) as the nonaqueous solvent, water is the limiting reagent. Mechanistic studies point to atom proton transfer (APT) as the rate limiting step in water oxidation catalysis.

Charged defects during alpha-irradiation of actinide oxides as revealed by Raman and luminescence spectroscopy

International Nuclear Information System (INIS)

Mohun, R.; Desgranges, L.; Léchelle, J.; Simon, P.; Guimbretière, G.; Canizarès, A.; Duval, F.; Jegou, C.; Magnin, M.; Clavier, N.; Dacheux, N.; Valot, C.; Vauchy, R.

2016-01-01

We have recently evidenced an original Raman signature of alpha irradiation-induced defects in UO 2 . In this study, we aim to determine whether the same signature also exists in different actinide oxides, namely ThO 2 and PuO 2 . Sintered UO 2 and ThO 2 were initially irradiated with 21 MeV He 2+ ions using a cyclotron device and were subjected to an in situ luminescence experiment followed by Raman analysis. In addition, a PuO 2 sample which had accumulated self-irradiation damage due to alpha particles was investigated only by Raman measurement. Results obtained for the initially white ThO 2 showed that a blue color appeared in the irradiated areas as well as luminescence signals during irradiation. However, Raman spectroscopic analysis showed the absence of Raman signature in ThO 2 . In contrast, the irradiated UO 2 and PuO 2 confirmed the presence of the Raman signature but no luminescence peaks were observed. The proposed mechanism involves electronic defects in ThO 2 , while a coupling between electronic defects and phonons is required to explain the Raman spectra for UO 2 and PuO 2 .

Thermodynamic and electrochemical properties of some rare earth cryptates and related complexes in propylene carbonate

International Nuclear Information System (INIS)

Loufouilou, E.L.

1986-03-01

The stability of trivalent lanthanide complexes with [1]-cryptand 22 and [2]-cryptands 222 and 211 and also tris (3.6- dioxa heptyl) amine (TDHA) is studied in propylene carbonate solution by potentiometry with Ag + as an auxiliary cation. Complexation enthalpies and entropies are determined for other complexes of some trivalent lanthanides (La, Er, Pr and Eu) with ligands 222, 221, 211, 22, 21, 18C6 and TDHA. [1]- and [2]- crytands are complexing agents more powerful than TDHA and crown-ethers 15C6 and 18C6. For ligands containing nitrogen complexe stability increase with RE atomic number but decrease for crown-ethers. In propylene carbonate complexes are stabilized by enthalpic effects, entropic contribution is variable. Polarographic reduction of samarium cryptate with ligand 222, 221 and 22 in propylene carbonate is reversible as in more solvating solvents water and methanol. Mixed complexes are formed with chlorides and this cryptate system is more difficult to reduce [fr

Rheological analysis of irradiated crosslinkable and scissionable polymers used for medical devices under different radiation conditions

Science.gov (United States)

Satti, A. J.; Ressia, J. A.; Cerrada, M. L.; Andreucetti, N. A.; Vallés, E. M.

2018-03-01

The effects on different synthetic polymers of distinct types of radiation, gamma rays and electron beam, under different atmospheres are followed by changes in their viscoelastic behavior. Taking into account the two main radioinduced reactions, crosslinking and scissioning of polymeric chains, liquid polydimethylsiloxane has been used as example of crosslinkable polymer and semi crystalline polypropylene as example of scissionable polymer. Propylene - 1-hexene copolymers have been also evaluated, and the effects of both reactions were clearly noticed. Accordingly, samples of those aforementioned polymers have been irradiated with 60Co gamma irradiation in air and under vacuum, and also with electron beam, at similar doses. Sinusoidal dynamic oscillation experiments showed a significant increase in branching and crosslinking reactions when specimens are irradiated under vacuum, while scissioning reactions were observed for the different polymers when irradiation takes place under air with either gamma irradiation or electron beam.

The effects of oxide evolution on mechanical properties in proton- and neutron-irradiated Fe-9%Cr ODS steel

Energy Technology Data Exchange (ETDEWEB)

Swenson, M.J., E-mail: matthewswenson1@u.boisestate.edu [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Dolph, C.K. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Wharry, J.P. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States)

2016-10-15

The objective of this study is to evaluate the effect of irradiation on the strengthening mechanisms of a model Fe-9%Cr oxide dispersion strengthened steel. The alloy was irradiated with protons or neutrons to a dose of 3 displacements per atoms at 500 °C. Nanoindentation was used to measure strengthening due to irradiation, with neutron irradiation causing a greater increase in yield strength than proton irradiation. The irradiated microstructures were characterized using transmission electron microscopy and atom probe tomography (APT). Cluster analysis reveals solute migration from the Y-Ti-O-rich nanoclusters to the surrounding matrix after both irradiations, though the effect is more pronounced in the neutron-irradiated specimen. Because the dissolved oxygen atoms occupy interstitial sites in the iron matrix, they contribute significantly to solid solution strengthening. The dispersed barrier hardening model relates microstructure evolution to the change in yield strength, but is only accurate if solid solution contributions to strengthening are considered simultaneously.

A DFT study on the effect of hydrogen in ethylene and propylene polymerization using a Ti-based heterogeneous Ziegler–Natta catalyst

KAUST Repository

Bahri-Laleh, Naeimeh

2012-11-01

Hydrogenolysis of a series of model Ziegler-Natta (Z-N) catalysts to form Ti-H bond was studied within DFT. We focused our efforts on Ti species attached to the (110) lateral cut of MgCl 2 which exist as different centres including Ti-C 2H 5, Ti-CH 2CH(CH 3) 2, and Ti-CH(CH 3)CH 2CH 3 in ethylene and propylene polymerization. In the next step, reactivity of Ti-H bond towards ethylene and propylene (1,2- and 2,1-) insertion was investigated. Results showed that insertion of ethylene and propylene into Ti-H bond has less barrier, in comparison with their insertion in Ti-C bond, however, ethylene and propylene 2,1- insertion lead to Ti-C 2H 5 and Ti-CH(CH 3) 2 centres respectively, which were stable due to strong β-agostic interactions. Finally, by considering different possible reactions of active centre, activity depression in ethylene polymerization and activity increase in propylene polymerization were explained in detail. © 2012 Elsevier B.V.

Measurement and protection of the oxidative damage induced by heavy-ion irradiation in human glioblastoma cell lines

International Nuclear Information System (INIS)

Moritake, Takashi; Tsuboi, Koji; Nose, Tadao

2003-01-01

The aim of this study is to evaluate the oxidative damage of DNA caused by low or high linear energy transfer (LET) radiation by measuring the level of 8-hydroxydeoxyguanosine (8-OHdG). Relationship between the 8-OHdG level and the LET value was assessed, and the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone) on DNA was evaluated as well. Solution containing salmon sperm DNA at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-ray or 290 MeV/u carbon beams with an LET range of 20-80 keV/μm. The 8-OHdG level in the DNA solution was measured by high performance liquid chromatography (HPLC) with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations from 10 μM to 1 mM and 8-OHdG level was measured by the same method after irradiation. The level of 8-OHdG increased dose-dependently after x-rays irradiation, and it was significantly suppressed by the presence of edaravone. The yield of 8-OHdG decreased as LET value increased, and the protection efficiency by edaravone decreased as LET value increased. (author)

Measurement and protection of the oxidative damage induced by heavy-ion irradiation in human glioblastoma cell lines

Energy Technology Data Exchange (ETDEWEB)

Moritake, Takashi; Tsuboi, Koji; Nose, Tadao [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Anzai, Kazunori; Ikota, Nobuo; Ando, Koichi; Ozawa, Toshihiko [National Inst. of Radiological Sciences, Chiba (Japan)

2003-04-01

The aim of this study is to evaluate the oxidative damage of DNA caused by low or high linear energy transfer (LET) radiation by measuring the level of 8-hydroxydeoxyguanosine (8-OHdG). Relationship between the 8-OHdG level and the LET value was assessed, and the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone) on DNA was evaluated as well. Solution containing salmon sperm DNA at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-ray or 290 MeV/u carbon beams with an LET range of 20-80 keV/{mu}m. The 8-OHdG level in the DNA solution was measured by high performance liquid chromatography (HPLC) with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations from 10 {mu}M to 1 mM and 8-OHdG level was measured by the same method after irradiation. The level of 8-OHdG increased dose-dependently after x-rays irradiation, and it was significantly suppressed by the presence of edaravone. The yield of 8-OHdG decreased as LET value increased, and the protection efficiency by edaravone decreased as LET value increased. (author)

A combined experimental and theoretical study on ethanol conversion to propylene over Y/ZrO2 catalyst

Science.gov (United States)

Wang, Fangfang; Xia, Wei; Mu, Xichuan; Chen, Kun; Si, Huimin; Li, Zhihao

2018-05-01

ZrO2-based catalysts doped with Y were prepared by co-precipitation method. The effect of yttrium modification on the selective conversion of bio-ethanol to propylene over ZrO2 catalysts was investigated. The physical and chemical properties of the catalysts were characterized by N2 adsorption-desorption method, temperature programmed desorption and X-ray diffraction. The maximum yield of propylene reached 44.0% over 0.03Y/ZrO2 catalyst. A coordination of acid-base properties accounts for the remarkable improvement of reaction activities over Y-doped ZrO2 catalysts in this investigation. On the basis of calculation results, it can be concluded that significant charge transfer occurs as a result of introduction of Y or O-vacancy. The adsorption of ethanol and propylene on perfect t-ZrO2 (1 0 1), defect t-ZrO2 (1 0 1) and Y/ZrO2 (1 0 1) surfaces were investigated with density functional theory (DFT). The adsorption for ethanol on Y/ZrO2 (1 0 1) and defect t-ZrO2 (1 0 1) surfaces are more stable than that on perfect t-ZrO2 (1 0 1). On the defect t-ZrO2 (1 0 1) surface, ethanol dominantly absorbs at the O-vacancy site, indicating that O-vacancy becomes the favorable adsorption site. On the Y/ZrO2 (1 0 1) and defect t-ZrO2 (1 0 1) surfaces, the adsorption energy of propylene decreases, which makes propylene desorb quickly after formation.

EVALUATION OF PROPYLENE CARBONATE IN AIR LOGISTICS CENTER (ALC) DEPAINTING OPERATIONS

Science.gov (United States)

This report summarizes a two-phase, laboratory-scale screening study that evaluated solvent blends containing propylene carbonate (PC) as a potential replacement for methyl ethyl ketone (MEK) in aircraft radome depainting operations. The study was conducted at Oklahoma City Air L...

Corrosion of zirconium alloys in nuclear reactors: A model for irradiation induced enhancement by local radiolysis in the porous oxide

Energy Technology Data Exchange (ETDEWEB)

Lemaignan, C; Salot, R [CEA/DRN/DTP, CENG-SECC, Grenoble (France)

1997-02-01

An analysis has been undertaken of the various cases of local enhancement of corrosion rate of zirconium alloys under irradiation. It is observed that in most cases a strong emission of energetic {beta}{sup -} is present leading to a local energy deposition rate higher than the core average. This suggests that the local transient radiolytic oxidizing species produced in the coolant by the {beta}{sup -} particles could contribute to corrosion enhancement, by increasing the local corrosion potential. This process is applicable to the local enhanced corrosion found in front of stainless steels structural parts, due to the contribution of Mn, and in front of Pt inserts or Cu-rich cruds. It explains also the irradiation corrosion enhancement of Cu-Zr alloys. Enhanced corrosion around neutron absorbing material is explained similarly by pair production from conversion of high energy capture photons in the cladding, leading to energetic electrons. The same process was found to be active with other highly ionizing species like {alpha} from Ni-rich alloys and fission products in homogeneous reactors. Due to the changes induced by the irradiation intensity on the concentration of the radiolytic species, the coolant chemistry, that controls the boundary conditions for oxide growth, has to be analyzed with respect to the local value of the energy deposition rate. An analysis has been undertaken which shows that, in a porous media, the water is exposed to a higher intensity than bulk water. This leads to a higher concentration of oxidizing radiolytic species at the root of the cracks of the porous oxide, and increases the corrosion rate under irradiation. This mechanism, deduced from the explanation proposed for localized irradiation enhanced corrosion, can be extended to the whole reactor core, where the general enhancement of Zr alloys corrosion under irradiation could be attributed to the general radiolysis in the porous zirconia. (author). 18 refs, 3 figs, 3 tabs.

In vitro biological test of resistance to oxidation: application to identification of irradiated food

International Nuclear Information System (INIS)

Blache, D.; Prost, M.; Raffi, J.

1991-01-01

The test presented here for the identification of ionized food is a direct application of a biological test of resistance to oxidation, put on for an evaluation of antioxidant properties of pharmaceutic molecules and for the study of free radicals in biology. Consequently, the main part of this datum is relative to this biological test. We only point out, when necessary, how we plan to use it for food items. Our aim in this paper is to present a simple biological test (SPIRAL Patent Pending) to measure the total anti oxidative defence status of individuals utilizing some easy to handle cells: circulating cells. In this presentation, we only limited to red blood cells, but any cell could be used after suitable adaptation of the procedure. The first experiments carried out on irradiated foods are promising, even for foodstuffs in liquid state, but we have surely to do a lot of new ones in order to improve the specificity of this test with regard to irradiation and to define with which food it can be used. (9 refs; 15 figs)

Simulation of the chemical state of irradiated oxide fuel; influence of the internal corrosion on the mechanical properties of Zry-4 tubing

International Nuclear Information System (INIS)

Hofmann, P.

1979-03-01

Zircaloy is not compatible with oxide fuel nor with some fission product elements. Therefore, chemical interaction between the irradiated oxide fuel and the Zry cladding material take place, especially at temperatures that can be reached during reactor incidents (ATWS, LOCA). In order to find out which influence the chemical interaction between the fission products and the Zry cladding material have on the mechanical properties of Zry-4 tubing out-of-pile burst experiments and creep rupture tests have been performed at temperatures >=600 0 C with short tube specimens containing simulated fission products. First of all, assessments of the chemical state of irradiated oxide fuel were performed and a method is described for introducing simulated fission product species into fresh oxide fuel for irradiation tests. As the test results of the out-of-pile studies show, only iodine can lead to a low ductility failure of the Zry-tubing at temperatures >=600 0 C. However, the influence of iodine on the deformation behavior of Zry-tubing can be neglected above 850 0 C. (orig.) [de

Effect of Thai banana (Musa AA group) in reducing accumulation of oxidation end products in UVB-irradiated mouse skin.

Science.gov (United States)

Leerach, Nontaphat; Yakaew, Swanya; Phimnuan, Preeyawass; Soimee, Wichuda; Nakyai, Wongnapa; Luangbudnark, Witoo; Viyoch, Jarupa

2017-03-01

Chronic UVB exposure causes skin disorders and cancer through DNA strand breaks and oxidation of numerous functional groups of proteins and lipids in the skin. In this study, we investigated the effects of Thai banana (Musa AA group, "Khai," and Musa ABB group, "Namwa") on the prevention of UVB-induced skin damage when fed to male ICR mice. Mice were orally fed banana (Khai or Namwa) fruit pulps at dose of 1mg/g body weight/day for 12weeks. The shaved backs of the mice were irradiated with UVB for 12weeks. The intensity dose of UVB-exposure was increased from 54mJ/cm 2 /exposure at week 1 to 126mJ/cm 2 /exposure at week 12. A significant increase in skin thickness, lipid peroxidation, protein oxidation end products, and expression of MMP-1 was observed in UVB-irradiated mouse skin. A reduction in the accumulation of oxidation end products was found in the skin of UVB-irradiated mice receiving Khai. This occurred in conjunction with a reduction in MMP-1 expression, inhibition of epidermal thickening, and induction of γ-GCS expression. The dietary intake of Khai prevented skin damage from chronic UVB exposure by increased γ-GCS expression and reduced oxidation end products included carbonyls, malondialdehyde and 4-hydroxynonenal. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

Science.gov (United States)

Singh, Hemant Kr.; Avasthi, D. K.; Aggarwal, Shruti

2015-06-01

Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO2:F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In2O3:Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag+9 ions at fluences ranging from 3.0 × 1011 ions/cm2 to 3.0 × 1013 ions/cm2. The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications.

Problems of selectivity in liquid-phase oxidation

Energy Technology Data Exchange (ETDEWEB)

Emanuel, N M

1978-07-01

Based on a kinetic analysis of a generalized scheme for radical-chain process and on published experimental results, factors determining the selectivities of various liquid-phase oxidations of organic compounds are examined, including the kinetic chain length, molecular and chain decomposition of products, and competing routes in the initiated oxidation or autoxidation of hydrocarbons to peroxides. Also discussed are selective inhibition of undesirable routes in chain reactions, e.g., styrene and acetaldehyde co-oxidation; activation of molecular oxygen by variable-valence metal compounds used as homogeneous catalysts; modeling of fermentative processes by oxidation of hydrocarbons in complex catalytic systems, e.g., hydroxylation of alkanes, epoxidation or carbonylation of olefins, or oxidation of alcohols and ketones to acids; and the mechanisms of heterogeneous catalysis in liquid-phase reactions, e.g., oxidation of alkylaromatic hydrocarbons to peroxides and co-oxidation of propylene and acetaldehyde.

Increase of propylene production and recovery in a PETROBRAS FCC units; Aumento da producao e recuperacao de propeno em uma Unidade de FCC da PETROBRAS

Energy Technology Data Exchange (ETDEWEB)

Penna, Elisangela Melo; Pinho, Andrea de Rezende; Wolff, Marcelo Straubel [Petroleo Brasileiro S.A (PETROBRAS), Rio de Janeiro, RJ (Brazil)

2012-07-01

Propylene is one of the major petrochemical raw materials and its demand has been growing rapidly in recent years. Projections for future years indicate that the growth in propylene production via pyrolysis tends to be lower than the growth in the demand for ethylene, creating a supply deficit of this product. The FCC units are in a unique position to meet this increase in propylene demand due to its operational flexibility. Although their primary function in recent decades has been the gasoline production, FCC units are often operated for maximizing other products, such as LPG or distillates. At the FCC conversion section, the increase of propylene yield requires some increase in reaction severity, which can be obtained by increasing reactor riser temperature, and the use of catalyst additives based on ZSM-5. However, besides maximizing the propylene production in the reactor, a second objective should be pursued: the propylene recovery increase in the gas recovery section. In this section, the yield is affected by the gas compressor performance, the equipment design and process scheme. Eventually, new equipment may be installed, such as chillers, aimed at improving the absorption system. Predicting a real increase in propylene demand in the Brazilian market, this study aims to evaluate the adequacy of the gas recovery section of a PETROBRAS FCC unit, analyzing the impacts that a new products yields profile, which bend the propylene production compared to a conventional operation, would cause on this unit. In this paper, the main limitations and modifications that would be needed for an operation were identified, aiming at maximizing the propylene production, as well as proposed changes in the hardware of the unit. (author)

Limitations of using Raman microscopy for the analysis of high-content-carbon-filled ethylene propylene diene monomer rubber

DEFF Research Database (Denmark)

Ghanbari-Siahkali, A.; Almdal, K.; Kingshott, P.

2003-01-01

The effects of laser irradiation on changes to the surface chemistry and structure of a commercially available ethylene propylene diene monomer (EPDM) rubber sample after Raman microscopy analysis was investigated. The Raman measurements were carried out with different levels of laser power...... on the sample, ranging from 4.55 mW to 0.09 mW. The surface of the EPDM was analyzed before and after laser exposure using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The techniques have surface probe depths of approximately less...... than or equal to10 nm and 1 mum, respectively. Both sets of analysis show that ingredients of the blended EPDM rubber "bloom" to the surface as a result of local heating that takes place due to the absorption of laser by carbon black during the Raman analysis. Scanning electron microscopy (SEM...

Reduction of irradiation off-odor and lipid oxidation in ground beef by α-tocopherol addition and the use of a charcoal pack

International Nuclear Information System (INIS)

Sohn, S.H.; Jang, A.; Kim, J.K.; Song, H.P.; Kim, J.H.; Lee, M.; Jo, C.

2009-01-01

A combination of a charcoal pack during irradiation and α-tocopherol addition into ground beef was applied to eliminate an irradiation characteristic off-odor and to retard the lipid oxidation caused by the irradiation process. Ground beef was mixed with 200 ppm α-tocopherol and gamma irradiated with 0, 5, and 10 kGy with or without a charcoal pack present during the irradiation treatment. The pH of the control group was lower than that of α-tocopherol and charcoal pack treatment initially but increased rapidly and showed higher pH at day 7. Addition of α-tocopherol with or without charcoal pack addition showed lower 2-thiobarbituric acid reactive substances values in irradiated ground beef at days 3 and 7 compared to those without addition. The color of ground beef was not significantly affected by the treatment. However, odor preference result showed that 10 kGy-irradiated ground beef with a combination of charcoal pack and α-tocopherol addition had higher scores than the control group regardless of irradiation. Solid-phase microextraction (SPME) gas chromatograph/mass spectrometry (GC/MS) analysis identified various volatile compounds that were created by irradiation of ground beef. These compounds were reduced or eliminated when a charcoal pack was used during the irradiation process. The results of the present study imply that combination of packaging with a charcoal pack during the irradiation process and addition of α-tocopherol into ground beef is a good method to effectively eliminate an irradiation off-odor and retard the lipid oxidation development in ground beef caused by irradiation

Reduction of irradiation off-odor and lipid oxidation in ground beef by {alpha}-tocopherol addition and the use of a charcoal pack

Energy Technology Data Exchange (ETDEWEB)

Sohn, S.H. [Busan Regional Food and Drug Administration, Busan 608-829 (Korea, Republic of); Jang, A. [National Institute of Animal Science, RDA, Suwon 441-706 (Korea, Republic of); Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, J.K. [Cooperative Research, Extension, and Education Service, Northern Marianas College, Saipan, MP 96950 (Korea, Republic of); Song, H.P. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, J.H. [Cooperative Research, Extension, and Education Service, Northern Marianas College, Saipan, MP 96950 (Korea, Republic of); Lee, M. [Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of); Jo, C. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)], E-mail: cheorun@cnu.ac.kr

2009-02-15

A combination of a charcoal pack during irradiation and {alpha}-tocopherol addition into ground beef was applied to eliminate an irradiation characteristic off-odor and to retard the lipid oxidation caused by the irradiation process. Ground beef was mixed with 200 ppm {alpha}-tocopherol and gamma irradiated with 0, 5, and 10 kGy with or without a charcoal pack present during the irradiation treatment. The pH of the control group was lower than that of {alpha}-tocopherol and charcoal pack treatment initially but increased rapidly and showed higher pH at day 7. Addition of {alpha}-tocopherol with or without charcoal pack addition showed lower 2-thiobarbituric acid reactive substances values in irradiated ground beef at days 3 and 7 compared to those without addition. The color of ground beef was not significantly affected by the treatment. However, odor preference result showed that 10 kGy-irradiated ground beef with a combination of charcoal pack and {alpha}-tocopherol addition had higher scores than the control group regardless of irradiation. Solid-phase microextraction (SPME) gas chromatograph/mass spectrometry (GC/MS) analysis identified various volatile compounds that were created by irradiation of ground beef. These compounds were reduced or eliminated when a charcoal pack was used during the irradiation process. The results of the present study imply that combination of packaging with a charcoal pack during the irradiation process and addition of {alpha}-tocopherol into ground beef is a good method to effectively eliminate an irradiation off-odor and retard the lipid oxidation development in ground beef caused by irradiation.

Correlation between donating or accepting electron behavior of the adsorbed CO or H_2 and its oxidation over TiO_2 under ultraviolet light irradiation

International Nuclear Information System (INIS)

Peng, Xiaoying; He, Zhoujun; Yang, Kai; Chen, Xun; Wang, Xuxu; Dai, Wenxin; Fu, Xianzhi

2016-01-01

Graphical abstract: Although both H_2 and CO can be thermodynamically oxidized by O_2 over TiO_2 under UV irradiation, only CO was oxidized by O_2 over TiO_2 due to its donating electrons to TiO_2, while H_2 was not oxidized by O_2 under the same condition due to its accepting electrons from TiO_2. - Highlights: • CO could but H_2 could not be oxidized over TiO_2 under UV irradiation. • Electron transfer behaviors of species adsorbed at TiO_2 were characterized by gas sensing testing. • Adsorbed CO donated electrons to TiO_2 but adsorbed H_2 accepted electrons from TiO_2 under UV irradiation. • Photocatalytic oxidation of species over TiO_2 maybe depends on the electron transfer direction between species and TiO_2. - Abstract: Although both H_2 and CO can be thermodynamically oxidized by O_2 over TiO_2 under ultraviolet light (UV) irradiation, it was found that CO not H_2 could be oxidized over an anatase TiO_2 in this work. The chemisorption results of CO and H_2 at TiO_2 surface under UV irradiation, investigated by a gas sensing testing, showed that CO adsorption at TiO_2 would cause the decrease of TiO_2 surface impedance, whereas H_2 adsorption would cause its increase. It is proposed that the CO adsorbed at TiO_2 donate electrons to TiO_2 (as a process of CO pre-oxidation), resulting in its oxidation. In contrast, the H_2 adsorbed at TiO_2 accept electrons from TiO_2 (as a process of H_2 pre-reduction), which makes it difficult to be oxidized. This result indicates that the photocatalytic oxidation of a reactant over TiO_2 not only depends on the formation of the photo-generated carriers and the subsequent activated oxidizing species, but maybe also depends on the electron transfer behavior at the interface of the adsorbed reactant and TiO_2.

Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

International Nuclear Information System (INIS)

Moritake, T.; Nose, T.; Tsuboi, K.; Anzai, K.; Ikota, N.; Ozawa, T.; Ando, K.

2003-01-01

The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/μm, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/μm. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 μM to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/μm. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation

Measurement and protection of the oxidative damage induced by high-LET carbon-ion irradiation in salmon sperm DNA solution

Energy Technology Data Exchange (ETDEWEB)

Moritake, T; Nose, T [University of Tsukuba, (Japan); Tsuboi, K [Institute of Clinical Medical Center, (Japan); Anzai, K; Ikota, N [National Institute of Radiological Sciences, (Japan); Ozawa, T [Redox Regulation Research Group, (Japan); Ando, K [Research Center of Charged Particle Therapy, (Japan). National Institution

2003-07-01

The aims of this study are to quantify the yield of hydroxyl radicals (OH) , and to evaluate the oxidative damage on DNA after high-linear energy transfer (LET) carbon-ion beams and x-rays. For this purpose, the relationship between the radiolytic yield of OH in aqueous solution and 8-hydroxydeoxyguanosine (8-OHdG) level in DNA solution were assessed after radiation. In addition, the anti-oxidative effect of 3-methyl-1-phenyl-2-pyrazonline-5-one (edaravone) on DNA was evaluated. Culture medium containing 200 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was irradiated with doses of 0 to 20 Gy with an LET of 20 to 90 keV/{mu}m, and the yields of OH were measured using an electron spin resonance (ESR) spectrometer. Salmon sperm DNA solution at a concentration of 1.0 mg/ml was irradiated with 10 Gy of x-rays or 290 MeV/nucleon carbon-ion beams with an LET range of 20-80 keV/{mu}m. 8-OHdG levels in the DNA solution were measured by HPLC with an electrochemical detector (ECD) after each irradiation. Edaravone was added to the DNA solution in final concentrations of 10 {mu}M to 1 mM and 8-OHdG levels were measured by the same method after irradiation. The yield of OH by carbon-ion radiolysis increased in proportion to the absorbed dose over the range of 0 to 20 Gy, and the yield of OH decreased as LET increased logarithmically from 20 to 90 keV/{mu}m. The level of 8-OHdG increased dose-dependently after x-ray irradiation, and it was significantly suppressed by edaravone. Furthermore, the yield of 8-OHdG and the protection efficiency by edaravone decreased as LET value increased. These unique findings provide further understanding of the indirect effect of high-LET radiation, and chemical protection of oxidative damage on DNA is important for clinical application of high-LET radiation.

Differential effects of low-temperature inhibition on the propylene induced autocatalysis of ethylene production, respiration and ripening of 'Hayward' kiwifruit

DEFF Research Database (Denmark)

Antunes, M. D C; Pateraki, I.; Kanellis, A. K.

2000-01-01

production and the respiration rise appeared earlier with increased propylene concentrations. Ripening proceeded immediately after propylene treatment, while ethylene autocatalysis needed a lag period of 24-72 h. The latter event was attributed to the delay found in the induction of 1-aminocyclopropane-1....... It is concluded that kiwifruit stored at 20°C behaves as a typical climacteric fruit, while at 10°C behaves like a non-climacteric fruit. We propose that the main reasons for the inhibition of the propylene induced (autocatalytic) ethylene production in kiwifruit at low temperature (≤ IO°C), are primarily...

Tritium breeding and release-rate kinetics from neutron-irradiated lithium oxide

International Nuclear Information System (INIS)

Quanci, J.F.

1989-01-01

The research encompasses the measurement of the tritium breeding and release-rate kinetics from lithium oxide, a ceramic tritium-breeding material. A thermal extraction apparatus which allows the accurate measurement of the total tritium inventory and release rate from lithium oxide samples under different temperatures, pressures and carrier-gas compositions with an uncertainty not exceeding 3% was developed. The goal of the Lithium Blanket Module program was to determine if advanced computer codes could accurately predict the tritium production in the lithium oxide blanket of a fusion power plant. A fusion blanket module prototype was built and irradiated with a deuterium-tritium fusion-neutron source. The tritium production throughout the module was modeled with the MCNP three dimensional Monte Carlo code and was compared to the assay of the tritium bred in the module. The MCNP code accurately predicted tritium-breeding trends but underestimated the overall tritium breeding by 30%. The release rate of tritium from small grain polycrystalline sintered lithium oxides with a helium carrier gas from 300 to 450 C was found to be controlled by the first order surface desorption of monotritiated water. When small amounts of hydrogen were added to the helium carrier gas, the first order rate constant increased from the isotopic exchange of hydrogen for tritium at the lithium oxide surface occurring in parallel with the first order desorption process. The isotopic-exchange first order rate constant temperature dependence and hydrogen partial pressure dependence were evaluated

Gamma-induced reactions of bromo-ethane with olefines. Addition of ethyl radicals to hexene-1 and propylene

International Nuclear Information System (INIS)

Myshkin, V.E.; Shostenko, A.G.; Zagorets, P.A.; Pchelkin, A.I.; Markova, K.G.

1978-01-01

Radiation interaction of bromo-ethane with propylene and 1-hexene has been studied with the aim to investigate the action of γ-radiation on bromalkanes. The absorbed dose rate is 50 rad/s. The reaction products separated by preparative chromatography have been identified with infrared spectroscopy, elemental, chromatographic, and other physico-chemical methods of analysis. It has been established that the reaction with propylene gives rise to telomers whereas interaction of bromo-ethane with 1-hexene yields only the addition product (4-bromoctane). The activation energy of the reactions of adding ethyl radicals to 1-hexene and propylene has been found equal to (3.8+-0.4 kcal/mol) and (2.2+-0.2 kcal/mol), respectively. The activation energy of the reaction of chain transfer through bromo-ethane is (3.7+-0.3 kcal/mol.)

Ionic conductivity and dielectric permittivity of PEO-LiClO4 solid polymer electrolyte plasticized with propylene carbonate

Directory of Open Access Journals (Sweden)

S. Das

2015-02-01

Full Text Available We have studied ionic conductivity and dielectric permittivity of PEO-LiClO4 solid polymer electrolyte plasticized with propylene carbonate. Differential scanning calorimetry and X-ray diffraction studies confirm minimum volume fraction of crystalline phase for the polymer electrolyte with 40 wt. % propylene carbonate. The ionic conductivity exhibits a maximum for the same composition. The temperature dependence of the ionic conductivity has been well interpreted using Vogel-Tamman-Fulcher equation. Ion-ion interactions in the polymer electrolytes have been studied using Raman spectra and the concentrations of free ions, ion-pairs and ion-aggregates have been determined. The ionic conductivity increases due to the increase of free ions with the increase of propylene carbonate content. But for higher content of propylene carbonate, the ionic conductivity decreases due to the increase of concentrations of ion-pairs and ion-aggregates. To get further insights into the ion dynamics, the experimental data for the complex dielectric permittivity have been studied using Havriliak–Negami function. The variation of relaxation time with temperature obtained from this formalism follows Vogel-Tamman-Fulcher equation similar to the ionic conductivity.

Irradiation of inert matrix and mixed oxide fuel in the Halden test reactor

International Nuclear Information System (INIS)

Hellwig, Ch.; Kasemeyer, U.

2001-01-01

In a new type of fuel, called Inert Matrix Fuel (IMF), plutonium is embedded in a U-free matrix. This offers advantages for more efficient plutonium consumption, higher proliferation resistance, and for inert behaviour later in a waste repository. In the fuel type investigated at PSI, plutonium is dissolved in yttrium-stabilized zirconium oxide (YSZ), a highly radiation-resistant cubic phase, with addition of erbium as burnable poison for reactivity control. A first irradiation experiment of YSZ-based IMF is ongoing in the OECD Material Test Reactor in Halden (HBWR), together with MOX fuel (Rig IFA-651.1). The experiment is described herein and results are presented of the first 120 days of irradiation with an average assembly burnup of 47 kWd/cm 3 . The results are compared with neutronic calculations performed before the experiment, and are used to model the fuel behaviour with the PSI-modified TRANSURANUS code. The measured fuel temperatures are within the expected range. An unexpectedly strong densification of the IMF during the first irradiation cycle does not alter the fuel temperatures. An explanation for this behaviour is proposed. The irradiation at higher linear heat rates during forthcoming cycles will deliver information about the fission gas release behaviour of the IMF. (author)

Irradiation of inert matrix and mixed oxide fuel in the Halden test reactor

Energy Technology Data Exchange (ETDEWEB)

Hellwig, Ch.; Kasemeyer, U

2001-03-01

In a new type of fuel, called Inert Matrix Fuel (IMF), plutonium is embedded in a U-free matrix. This offers advantages for more efficient plutonium consumption, higher proliferation resistance, and for inert behaviour later in a waste repository. In the fuel type investigated at PSI, plutonium is dissolved in yttrium-stabilized zirconium oxide (YSZ), a highly radiation-resistant cubic phase, with addition of erbium as burnable poison for reactivity control. A first irradiation experiment of YSZ-based IMF is ongoing in the OECD Material Test Reactor in Halden (HBWR), together with MOX fuel (Rig IFA-651.1). The experiment is described herein and results are presented of the first 120 days of irradiation with an average assembly burnup of 47 kWd/cm{sup 3}. The results are compared with neutronic calculations performed before the experiment, and are used to model the fuel behaviour with the PSI-modified TRANSURANUS code. The measured fuel temperatures are within the expected range. An unexpectedly strong densification of the IMF during the first irradiation cycle does not alter the fuel temperatures. An explanation for this behaviour is proposed. The irradiation at higher linear heat rates during forthcoming cycles will deliver information about the fission gas release behaviour of the IMF. (author)

Oxidative degradation of phenols in sono-Fenton-like systems upon high-frequency ultrasound irradiation

Science.gov (United States)

Aseev, D. G.; Sizykh, M. R.; Batoeva, A. A.

2017-12-01

The kinetics of oxidative degradation of phenol and chlorophenols upon acoustic cavitation in the megahertz range (1.7 MHz) is studied experimentally in model systems, and the involvement of in situ generated reactive oxygen species (ROSs) is demonstrated. The phenols subjected to high frequency ultrasound (HFUS) are ranked in terms of their rate of conversion: 2,4,6-trichlorophenol > 2,4-dichlorophenol 2-chlorophenol > 4-chlorophenol phenol. Oxidative degradation upon HFUS irradiation is most efficient at low concentrations of pollutants, due to the low steady-state concentrations of the in situ generated ROSs. A dramatic increase is observed in the efficiency of oxidation in several sonochemical oxidative systems (HFUS in combination with other chemical oxidative factors). The system with added Fe2+ (a sono-Fenton system) derives its efficiency from hydrogen peroxide generated in situ as a result of the recombination of OH radicals. The S2O8 2-/Fe2+/HFUS system has a synergetic effect on substrate oxidation that is attributed to a radical chain mechanism. In terms of the oxidation rates, degrees of conversion, and specific energy efficiencies of 4-chlorophenol oxidation based on the amount of oxidized substance per unit of expended energy the considered sonochemical oxidative systems form the series HFUS < S2O8 2-/HFUS < S2O8 2-/Fe2+/HFUS.

Performance of 6FDA–6FpDA polyimide for propylene/propane separations

KAUST Repository

Das, Mita; Koros, William J.

2010-01-01

This work addresses the challenges faced by previous researchers with 6FDA-6FpDA polyimide for propylene/propane separations due to plasticization. A study of film annealing temperature is reported to optimize plasticization suppression in elevated

Point defects and irradiation in oxides: simulations at the atomic scale; Defauts ponctuels et irradiation dans les oxydes: simulation a l'echelle atomique

Energy Technology Data Exchange (ETDEWEB)

Crocombette, J.P

2005-12-15

The studies done by Jean-Paul Crocombette between 1996 and 2005 in the Service de Recherches de Metallurgie Physique of the Direction de l'Energie Nucleaire in Saclay are presented in this Habilitation thesis. These works were part of the material science researches on the ageing, especially under irradiation, of oxides of interest for the nuclear industry. In this context simulation studies at the atomic scale were performed on two elementary components of ageing under irradiation : point defects and displacement cascades ; using two complementary simulation techniques : ab initio electronic structure calculations and empirical potential molecular dynamics. The first part deals with point defects : self defects (vacancies or interstitials) or hetero-atomic dopants. One first recalls the energetics of such defects in oxides, the specific features of defects calculations and the expected accuracy of these calculations. Then one presents the results obtained on uranium dioxide, oxygen in silver and amorphous silica. The second part tackles the modelling of disintegration recoil nuclei in various?displacement cascades created by crystalline matrices for actinide waste disposal. Cascade calculations give access to the amorphization mechanisms under irradiation of these materials. One thus predicts that the amorphization in zircon takes place directly in the tracks whereas in lanthanum zirconate, the amorphization proceeds through the accumulation of point defects. Finally the prospects of these studies are discussed. (author)

Development of packed bed membrane reactor for the oxidative dehydrogenation of propane

NARCIS (Netherlands)

Kotanjac, Zeljko

2009-01-01

In this research, a reactor concept for the oxidative dehydrogenation of propane was studied. First a literature survey was performed, to investigate which are the best catalyst systems and best operating conditions that result in the largest propylene yield. In the kinetic study of ODHP over a

Simultaneous determination of mercapturic acids derived from ethylene oxide (HEMA), propylene oxide (2-HPMA), acrolein (3-HPMA), acrylamide (AAMA) and N,N-dimethylformamide (AMCC) in human urine using liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Schettgen, Thomas; Musiol, Anita; Kraus, Thomas

2008-09-01

Mercapturic acids are highly important and specific biomarkers of exposure to carcinogenic substances in occupational and environmental medicine. We have developed and validated a reliable, specific and very sensitive method for the simultaneous determination of five mercapturic acids derived from several high-production chemicals used in industry, namely ethylene oxide, propylene oxide, acrylamide, acrolein and N,N-dimethylformamide. Analytes are enriched and cleaned up from urinary matrix by offline solid-phase extraction. The mercapturic acids are subsequently separated by means of high-performance liquid chromatography on a Luna C8 (2) column and specifically quantified by tandem mass spectrometric detection using isotopically labelled analytes as internal standards. The limits of detection (LODs) for N-acetyl-S-2-carbamoylethylcysteine (AAMA) and N-acetyl-S-2-hydroxyethylcysteine (HEMA) were 2.5 microg/L and 0.5 microg/L urine, while for N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), N-acetyl-S-2-hydroxypropylcysteine (2-HPMA) and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) it was 5 microg/L. These LODs were sufficient to detect the background exposure of the general population. We applied the method on spot urine samples of 28 subjects of the general population with no known occupational exposure to these substances. Median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC in non-smokers (n = 14) were 52.6, 2.0, 155, 7.1 and 113.6 microg/L, respectively. In smokers (n = 14), median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC were 243, 5.3, 1681, 41.7 and 822 microg/L, respectively. Due to the simultaneous quantification of these mercapturic acids, our method is well suited for the screening of workers with multiple chemical exposures as well as the determination of the background excretion of the general population.

Aluminium and Gamma Irradiation Induced Oxidative Damage in Brain Tissue of Male Rats - Protective Role of Ferulic Acid

International Nuclear Information System (INIS)

Mansour, S.Z.; Hanafi, N.; Noaman, E.

2011-01-01

The current study was carried out to investigate the potential role of ferulic acid (FA) against Aluminium chloride (AlCl 3 ), γ- radiation either alone or combination induced oxidative stress in brain tissue of Wistar rats. The period of the experiment was eight weeks. Animals were administrated by aluminium chloride at a dose of 8.5 mg/kg/day and exposed to a single dose (4 Gy) of γ-radiation. FA was administered orally (50 mg/Kg body weight)/day. Histopathological observations and myeloid protein distribution were recorded in brain tissue. Induction of oxidative stress was recorded after all exposures. Brain tissue of AlCl 3 and γ- irradiation treatments either alone or combined revealed many altered changes and myeloid protein distribution. Also a decrease in serotonin concentration was recorded. An increase in Malonaldialdahyde (MDA) and acetylcholinesterase activity and percentage of saturated fatty acids in plasma and brain tissue was recorded. Reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) in blood and brain showed a significant decrease. Treatment of AlCl 3 loaded animals by FA showed simple atrophy as shrunken morphology saw in amyotrophic lateral sclerosis and a decrease in myeloid protein deposition. FA treatment of AlCl 3 loaded or irradiated animals represented a significant increase in serotonin concentration and ameliorated affects on oxidative stress markers, acetylcholinesterase activity and percentage of saturated fatty acids in plasma and brain tissue. In conclusion FA has a role in reducing the oxidative stress of AlCl 3 and γ- irradiation on brain tissue of rats

Photocatalytic oxidation of indoor toluene: Process risk analysis and influence of relative humidity, photocatalysts, and VUV irradiation

International Nuclear Information System (INIS)

Zhao, Weirong; Dai, Jiusong; Liu, Feifei; Bao, Jiaze; Wang, Yan; Yang, Yong; Yang, Yanan; Zhao, Dongye

2012-01-01

Concentrations of 13 gaseous intermediates in photocatalytic oxidation (PCO) of toluene in indoor air were determined in real-time by proton transfer reaction mass spectrometry and desorption intensities of 7 adsorbed intermediates on the surface of photocatalysts were detected by temperature‐programmed desorption‐mass spectrometry. Effects of relative humidity (RH), photocatalysts, and vacuum ultraviolet (VUV) irradiation on the distribution and category of the intermediates and health risk influence index (η) were investigated. RH enhances the formation rate of hydroxide radicals, leading to more intermediates with higher oxidation states in gas phase. N doping promotes the separation of photo-generated electrons and holes and enhances PCO activity accordingly. VUV irradiation results in higher mineralization rate and more intermediates with higher oxidation states and lower toxicity e.g. carboxylic acids. Health risk analysis indicates that higher RH, N doping of TiO 2 , and VUV lead to “greener” intermediates and smaller η. Finally, a conceptual diagram was proposed to exhibit the scenario of η varied with extent of mineralization for various toxicities of inlet pollutants. Highlights: ► 13 volatile intermediates in PCO of toluene were determined in real-time by PTR-MS. ► 7 adsorbed intermediates on surface of photocatalyst were determined by TPD-MS. ► Higher RH, N doping of TiO 2 , and VUV irradiation lead to “greener” intermediates. ► Health risk index relies on extent of mineralization and toxicities of inlet VOCs.

Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

Science.gov (United States)

Veerapandian, Murugan; Zhang, Linghe; Krishnamoorthy, Karthikeyan; Yun, Kyusik

2013-10-01

A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml-1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml-1 for Bacillus subtilis and 0.5 μg ml-1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside.

Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

International Nuclear Information System (INIS)

Veerapandian, Murugan; Zhang, Linghe; Yun, Kyusik; Krishnamoorthy, Karthikeyan

2013-01-01

A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml −1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml −1 for Bacillus subtilis and 0.5 μg ml −1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside. (paper)

Effects of zinc oxide and titanium dioxide nanoparticles on green algae under visible, UVA, and UVB irradiations: no evidence of enhanced algal toxicity under UV pre-irradiation.

Science.gov (United States)

Lee, Woo-Mi; An, Youn-Joo

2013-04-01

Some metal oxide nanoparticles are photoreactive, thus raising concerns regarding phototoxicity. This study evaluated ecotoxic effects of zinc oxide nanoparticles and titanium dioxide nanoparticles to the green algae Pseudokirchneriella subcapitata under visible, UVA, and UVB irradiation conditions. The nanoparticles were prepared in algal test medium, and the test units were pre-irradiated by UV light in a photoreactor. Algal assays were also conducted with visible, UVA or UVB lights only without nanoparticles. Algal growth was found to be inhibited as the nanoparticle concentration increased, and ZnO NPs caused destabilization of the cell membranes. We also noted that the inhibitory effects on the growth of algae were not enhanced under UV pre-irradiation conditions. This phenomenon was attributed to the photocatalytic activities of ZnO NPs and TiO2 NPs in both the visible and UV regions. The toxicity of ZnO NPs was almost entirely the consequence of the dissolved free zinc ions. This study provides us with an improved understanding of toxicity of photoreactive nanoparticles as related to the effects of visible and UV lights. Copyright © 2012 Elsevier Ltd. All rights reserved.

TS-1 supported highly dispersed sub-5 nm gold nanoparticles toward direct propylene epoxidation using H2 and O2

Science.gov (United States)

Li, Naixu; Chen, Yong; Shen, Quanhao; Yang, Bin; Liu, Ming; Wei, Lingfei; Tian, Wei; Zhou, Jiancheng

2018-05-01

We report a simple and efficient method for the preparation of highly dispersed Au nanoparticles (< 5 nm) on TS-1 substrate. The synthesis relies on the use of NaBH4 as a reductant for rapid Au atom generation, as well as PVA as a capping agent confining the particle size and dispersion. The samples were characterized by N2 physisorption, inductively coupled plasma mass spectrometry, power X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, CO pulse chemisorption and thermogravimetric analysis. The size of Au particles can be controlled in the range of 3-5 nm. The supported catalyst shows both good activity and selectivity for propylene oxide (PO) generation from direct propylene epoxidation. An optimal performance with PO formation rate of 102.94 gPO h-1 kg-1cat and selectivity of 84.83% is achieved over 2.0 wt% Au/TS-1 catalyst, which is prepared by controlling PVA/Au3+ mass ratio of 1.5/1 and NaBH4/Au3+ mole ratio of 5/1. After 50 h test at 200 °C, no significant decrement of both catalytic activity and PO selectivity can be observed, indicating the excellent thermally stability of the catalyst. Furthermore, a possible reaction mechanism is described on basis of the previous researches and our experimental results.

Results of the irradiation of mixed UO2 - PuO2 oxide fuel elements

International Nuclear Information System (INIS)

Mikailoff, H.; Mustelier, J.P.; Bloch, J.; Ezran, L.; Hayet, L.

1966-01-01

In order to study the behaviour of fuel elements used for the first charge of the reactor Rapsodie, a first batch of eleven needles was irradiated in the reactor EL3 and then examined. These needles (having a shape very similar lo that of the actual needles to be used) were made up of a stack of sintered mixed-oxide pellets: UO 2 containing about 10 per cent of PuO 2 . The density was 85 to 97 per cent of the theoretical, value. The diametral gap between the oxide and the stainless steel can was between 0,06 and 0,27 mm. The specific powers varied from 1230 to 2700 W/cm 3 and the can temperature was between 450 and 630 C. The maximum burn-up attained was 22000 MW days/tonne. Examination of the needles (metrology, radiography and γ-spectrography) revealed certain macroscopic changes, and the evolution of the fuel was shown by micrographic studies. These observations were used, together with flux measurements results, to calculate the temperature distribution inside the fuel. The volume of the fission gas produced was measured in some of the samples; the results are interpreted taking into account the temperature distribution in the oxide and the burn-up attained. Finally a study was made both of the behaviour of a fuel element whose central part was molten during irradiation, and of the effect of sodium which had penetrated into some of the samples following can rupture. (author) [fr

Kinetics that govern the release of tritium from neutron-irradiated lithium oxide

International Nuclear Information System (INIS)

Bertone, P.C.

1986-01-01

The Lithium Blanket Module (LBM) program being conducted at the Princeton Plasma Physics Laboratory requires that tritium concentrations as low as 0.1 nCi/g, bred in both LBM lithium oxide pellets and gram-size lithium samples, be measured with an uncertainty not exceeding +/-6%. This thesis reports two satisfactory methods of assaying LBM pellets and one satisfactory method of assaying lithium samples. Results of a fundamental kinetic investigation are also reported. The thermally driven release of tritium from neutron-irradiated lithium oxide pellets is studied between the temperatures of 300 and 400 0 C. The observed release clearly obeys first-order kinetics, and the governing activation energy appears to be 28.4 kcal/mole. Finally, a model is presented that may explain the thermally driven release of tritium from a lithium oxide crystal and assemblies thereof. It predicts that under most circumstances the release is controlled by either the diffusion of a tritiated species through the crystal, or by the desorption of tritiated water from it

Some physical properties of irradiated and non-irradiated oxide glasses containing uranium

International Nuclear Information System (INIS)

Simon, V.; Ardelean, I.; Simon, S.; Cozar, O.; Milea, I.; Lupsa, I.; Mih, V.

1995-01-01

The x U O 3 (1-x) [2 P 2 O 5 · Na 2 O] non-irradiated and gamma irradiated glasses (0 3+ , U 4+ and U 5+ ions. The gamma irradiation induces paramagnetic defects around the glass network forming sites occupied by phosphorous atoms. The non-irradiated samples are weak paramagnetic up to x = 0.1. For higher U O 3 concentration (0.1 < x ≤ 0.2) the magnetic measurements indicated a larger number of paramagnetic ions which are magnetically isolated and exhibit a Curie type behaviour. (author) 5 figs., 14 refs

Effects of γ- and x-irradiation upon activity and selectivity of a supported silver catalyst in the oxidation of ethylene and carbon monoxide

International Nuclear Information System (INIS)

Mora Vallejo, R.J.

1975-01-01

Effects of γ and x-radiation on catalytic selectivity of supported silver catalysts for production of ethylene oxide via ethylene oxidation were compared by determination of radio-induced changes in conversion-yield profiles. Influence of photon energy on the kinetics of the irradiation process was studied by determination of conversion-yield profiles, using samples of catalyst exposed to x-rays of different mean photon energy and γ-rays for different cumulative periods of time. The effect of γ-radiation on catalytic activity of the same silver catalysts for carbon monoxide oxidation was analyzed by determination of the reaction kinetics before and after catalyst irradiation

3-Amino-1,2,4-triazole Limits the Oxidative Damage in UVA-Irradiated Dysplastic Keratinocytes

Directory of Open Access Journals (Sweden)

Marina Tamara Nechifor

2017-01-01

Full Text Available Reactive oxygen species (ROS generated by UVA irradiation affect the keratinocyte cell membrane, DNA, and proteins and may cause serious injury to the skin. Treating human dysplastic keratinocytes (DOK with 3-amino-1,2,4-triazole (AMT, a common catalase inhibitor, induced a compensatory mechanism for the hydrogen peroxide detoxification, which included a rise in glutathione peroxidase and glutathione reductase activities. Here, we examined a possible role of AMT in protecting a human DOK cell line against UVA-induced damage. In DOK cells exposed to UVA irradiation, we observed a substantial decrease in antioxidant enzymatic activities, such as catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase and an increase in lipid peroxidation and protein oxidation levels. Treating DOK cells with AMT prior to UVA exposure enhanced the activities of glutathione peroxidase, glutathione reductase, and glutathione-S-transferase, relative to nontreated cells. The enhanced antioxidant activities were correlated with decreased protein oxidation levels. Based on these results, we suggest that AMT may protect dysplastic keratinocytes against the harmful effects of UVA radiation.

Short-term anoxic conditioning hormesis boosts antioxidant defenses, lowers oxidative damage following irradiation and enhances male sexual performance in the Caribbean fruit fly, Anastrepha suspensa

Energy Technology Data Exchange (ETDEWEB)

Lopez-Martinez, Giancarlo; Hahn, Daniel A [Department of Entomology and Nematology, University of Florida, Gainesville, FL (United States)

2013-01-15

Most organisms are repeatedly exposed to oxidative stress from multiple sources throughout their lifetimes, potentially affecting all aspects of organismal performance. Here we test whether exposure to a conditioning bout of anoxia early in adulthood induces a hormetic response that confers resistance to oxidative stress and enhances male sexual performance later in life in the Caribbean fruit fly, Anastrepha suspensa. Anoxic conditioning of adults prior to emergence led to an increase in antioxidant capacity driven by mitochondrial superoxide dismutase and glutathione peroxidase. When exposed to gamma irradiation, a strong oxidative stressor, males that received anoxic conditioning had lower lipid and protein oxidative damage at sexual maturity. Anoxia conditioning led to greater male sexual competitiveness compared with unconditioned males when both were irradiated, although there was no effect of anoxia conditioning on mating competitiveness in unirradiated males. Anoxia also led to higher adult emergence rates and greater flight ability in irradiation-stressed flies while preserving steriity. Thus, hormetic treatments that increased antioxidant enzyme activity also improved male performance after irradiation, suggesting that antioxidant enzymes play an important role in mediating the relationship between oxidative stress and sexual selection. Furthermore, our work has important applied implications for the sterile insect technique (SIT), an environmentally friendly method of insect pest control where males are sterilized by irradiation and deployed in the field to disrupt pest populations via mating. We suggest that hormetic treatments specifically designed to enhance antioxidant activity may produce more sexually competitive sterile males, thus improving the efficacy and economy of SIT programs. (author)

A DFT study on the effect of hydrogen in ethylene and propylene polymerization using a Ti-based heterogeneous Ziegler–Natta catalyst

KAUST Repository

Bahri-Laleh, Naeimeh; Nekoomanesh-Haghighi, Mehdi; Mirmohammadi, Seyed Amin

2012-01-01

-CH 2CH(CH 3) 2, and Ti-CH(CH 3)CH 2CH 3 in ethylene and propylene polymerization. In the next step, reactivity of Ti-H bond towards ethylene and propylene (1,2- and 2,1-) insertion was investigated. Results showed that insertion of ethylene

Catalytic activity of oxide cerium-molybdenum-tellurium catalysts in oxidation ammonolysis

International Nuclear Information System (INIS)

Dzhordano, N.; Bart, D.; Madzhori, R.

1984-01-01

A commercial catalyst containing a mixture of Ce-, Mo-, Te oxides deposited on SiO 2 is shown to manifest a high efficiency in oxidative ammonolysis of propylene (C 3 - ) to acrylonitrile (AN). The dependence of the catalytic properties on the catalyst composition and reaction conditions is studied. It is established that three-component mixtures are more active and selective than the systems with a lesser number of components. Using the catalyst with the optimum ratio of constituent oxides in a microreactor at 440 deg enabled one to achieve initial selectivity in terms of AN equal to 82.5% at 97% conversion of C 3 - . Acrolein, acetonitrile, HCN and nitrogen oxides are the reaction by-products. A supposition is made that the reaction proceeds via the formation of π-compleXes on the centres of Te(4). Setective oxidation occurs on oxygen atoms bonded with the Mo(6) ions. Tellurium enhances the molybdenum reducibleness due to delocalization of electrons, whereas the cerium addition to the mixture of tellurium- and molybdenum oxides increases the rate of molybdenum reoxidation and thus enhances the catalytic system stability

Electrochemical reduction of CO2 to CO over Zn in propylene carbonate/tetrabutylammonium perchlorate

Science.gov (United States)

Shen, Feng-xia; Shi, Jin; Chen, Tian-you; Shi, Feng; Li, Qing-yuan; Zhen, Jian-zheng; Li, Yun-fei; Dai, Yong-nian; Yang, Bin; Qu, Tao

2018-02-01

Developing low cost and high efficient electrode for carbon dioxide (CO2) reduction in organic media is essential for practical application. Zn is a cheap metal and has high catalytic effects on CO2 reduction to carbon monoxide (CO) in aqueous solution. However, little attention has been given to investigate the performance of Zn in organic media for CO2 reduction. In present work, we have conducted CO2 reduction in propylene carbonate/tetrabutylammonium perchlorate on Zn due to that propylene carbonate is a widely used industrial absorber, and tetrabutylammonium perchlorate is a commonly used organic supporting electrolyte. In addition, because electrochemical reduction of CO2 to CO naturally produces H2O, we have discussed water effects on CO2 reduction in propylene carbonate/tetrabutylammonium perchlorate+6.8 wt % H2O. Our experiment results reveal that the faradaic efficiency for CO formation reaches to 83%, and the current density remains stable at 6.72 mA/cm2 at voltage -2.3 V for 4 h. Interestingly, Zn presents higher catalytic activity than Ag, and slightly lower than Au. X-ray photoelectron spectroscopy results confirm that no poisonous species is formed and absorbed on the cathode, which is an important advantage in practical application.

Transient redistribution of intragranular fission gas in irradiated mixed oxide

International Nuclear Information System (INIS)

Hinman, C.A.; Randklev, E.H.

1981-01-01

Safety analyses for an LMFBR require a knowledge of the fuel and fission gas behavior under transient conditions. Analyses of microstructural data derived from transiently heated, irradiated, mixed oxide fuel specimens have allowed the calculation of the degree of nonequilibrium of intragranular bubbles formed during the transient. It is hypothesized that the observed over-pressurization of the intragranular bubbles mechanically loads the fuel within the grain, leading to a stress gradient derived force upon near-grain-surface bubbles, driving them preferentially to the grain boundaries. Using existing models for forced diffusion it can be estimated that the stress derived forces on bubbles are within the same magnitude, and possibly greater, than the forces derived from the thermal gradient

Ionic conductivity and dielectric permittivity of PEO-LiClO{sub 4} solid polymer electrolyte plasticized with propylene carbonate

Energy Technology Data Exchange (ETDEWEB)

Das, S.; Ghosh, A., E-mail: sspag@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2015-02-15

We have studied ionic conductivity and dielectric permittivity of PEO-LiClO{sub 4} solid polymer electrolyte plasticized with propylene carbonate. Differential scanning calorimetry and X-ray diffraction studies confirm minimum volume fraction of crystalline phase for the polymer electrolyte with 40 wt. % propylene carbonate. The ionic conductivity exhibits a maximum for the same composition. The temperature dependence of the ionic conductivity has been well interpreted using Vogel-Tamman-Fulcher equation. Ion-ion interactions in the polymer electrolytes have been studied using Raman spectra and the concentrations of free ions, ion-pairs and ion-aggregates have been determined. The ionic conductivity increases due to the increase of free ions with the increase of propylene carbonate content. But for higher content of propylene carbonate, the ionic conductivity decreases due to the increase of concentrations of ion-pairs and ion-aggregates. To get further insights into the ion dynamics, the experimental data for the complex dielectric permittivity have been studied using Havriliak–Negami function. The variation of relaxation time with temperature obtained from this formalism follows Vogel-Tamman-Fulcher equation similar to the ionic conductivity.

Study of bixin oxidation by ionizing irradiation; Estudo da oxidação da bixina pela radiação ionizante

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Thais N.; Teixeira, Paula S.; Moura, Eduardo de; Geraldo, Áurea Beatriz C., E-mail: thais.fonseca@fatec.sp.gov.br, E-mail: paulateixeirasant@gmail.com, E-mail: emoura@ipen.br, E-mail: ageraldo@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

Brazil is the world's largest producer of anatto, followed by Kenya and Peru. The fruit of the annatto tree is constituted by a capsule containing external spines and internal seeds with reddish coloration, providing a natural pigment which is environmentally efficient, being able to replace synthetic pigments and dyes. The active substance of the pigment is Bixin, which is a type of carotenoid which constitutes a greater percentage of pigment in these seeds and has a lipo soluble character. Bixin reacts with NaOH in a saponification reaction giving norbixin, which is water soluble. It is known that the destination of the dye extracted from the fruit is intended for industry, especially the food industry. The culture of annatto tree brings prospects of development in agricultural programs for medium and small producers, which are able to use decadent areas of other crops. In addition to the food sector, new applications for the pigment helps the development of family farming. The pigment extracted from annatto undergoes a natural oxidation; this work aims to evaluate this phenomenon and also the oxidation of the pigment after the irradiation process. This work also evaluates of the how the oxidation process is affected by irradiation and the modifications introduced to irradiated pigments. Irradiated and nonirradiated samples were characterized by thermogravimetry, UV-vis spectrophotometry and infrared spectroscopy (FTIR). The results are then discussed. (author)

Analysis of FT-IR for dosimetric characterization of poly(vinylidene fluoride - hexafluoropropylene) irradiated with high doses of gamma radiation

International Nuclear Information System (INIS)

Liz, Otavio Souza Rocha; Medeiros, Adriana de Souza

2011-01-01

Polymeric materials when exposed to ionizing radiation undergo changes such as the crosslinking and chain oxidation. Recently, the optical absorption intensities in the ultraviolet visible region (273 nm) due to radio- induction of conjugated C=C bonds in P(VDF-TrFE) copolymers has been successfully used for high dose dosimetry purposes in gamma fields ranging from 0.1 to 200 kGy. In this context, the interest of performing a systematic investigation on another fluorinated copolymer of PVDF, the (Polyvinylidene fluoride - hexa fluoro propylene) [P(VDF- HFP)] has come to light, not only for UV-VIS range but also for the near and medium infrared ranges. In this investigation FTIR and UV-Vis spectra, acquired before and after irradiation, were used to investigate the relationship between optical absorbance and delivered gamma doses ranging from 100 to 3,000 kGy. The results indicate that the absorption band at 1729 cm-1, originated by the chain oxidation through the radioinduction of C=O bonds, presents an unambiguous behavior with the delivered gamma doses in a very large extension, ranging from 0 to 1,000 kGy. This results lead to conclude that P(VDF-HFP) copolymer shows excellent dosimetric properties which make it able to be investigated as a high dose dosimeter

Antioxidant activity for spice oils (1) anti oxidative stability of thyme and caraway oil extracts under UV-irradiation

International Nuclear Information System (INIS)

Atef Ghazy, M.; Shaker, E.S.

2002-01-01

The anti oxidative activity for some spice essential oils have been investigated using thiocyanate method and compared with common natural antioxidant. The antioxidant activity for nine spice oils has been measured at 500 ppm after 13 days. The most potent one was the lemon grass (99.8), followed by orange peel, thyme, and caraway. The activities for these four oils were higher than that for Alpha-tocopherol (87.7%). Petitgrain, and geranium oils have marched activity but less than that for Alpha-tocopherol. No obvious has been found for citronella. fennel, and cardamon oils. The aqueous, butanoic, methanolic and hexanoic extracts for thyme and caraway oil exhibit effective anti oxidative activities under UV irradiation (254 nm) for 6 and 10 hr compared with that for alpha-tocopherol. The anti oxidative effect of thyme and caraway oil extracts were found to be strong and stable towards UV-irradiation, and equal to that for Alpha-tocopherol. Thyme's aqueous and caraway's hexanal extracts were the most potent extracts under the same conditions

Comparative effect of ethylene oxide and gamma irradiation on the chemical sensory and microbial quality of ginger, cinnamon, fennel and fenugreek

International Nuclear Information System (INIS)

Toofanian, F.; Stegeman

1986-01-01

The effect of gamma irradiation and ethylene oxide fumigation on the microbiological and sensory properties of ground cinnamon, ginger, fennel and fenugreek, and on the volatile oil content of ground cinnamon, ginger and fennel was investigated. Ground ginger, cinnamon, fennel and fenugreek were obtained from a Dutch trade company. Ginger originated from China, cinnamon was produced in Indonesia and fennel and fenugreek were produced in India. The samples were ground by the trade companies and divided in three parts. One part was fumigated by the trade companies at ambient temperatures during eight hours with ethylene oxide (EO) at a concentration of 1500/m 3 . The second part was gamma irradiated at room temperature in aluminium/polyethylene bags at the 40 KCi cobalt-60 research source of the pilot plant for food irradiation in Wageningen. The untreated, fumigated and irradiated samples were stored in gas-impermeable packages. It was found that for cinnamon and ginger a 6 KGy dose, for fennel, 6-10 KGy and for fenugreek 6-8 KGy dose were equal in microbial effects to the commercial established fumigation process. No significant change in the volatile oil content of the fumigated or irradiated cinnamon and fennel has been observed. Irradiation of ginger with a dose of 5 KGy resulted in a slight decrease of 14% while fumigated ginger showed no significant loss in volatile oil content. Between the untreated irradiated or fumigated spices no major differences in sensory properties were found