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Sample records for vhf epr analysis

  1. Use of vhf dielectric measurements for borehole formation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Poley, J.P.; Nooteboom, J.J.; de Waal, P.J.

    1978-01-01

    A study of the dielectric properties of sedimentary rocks at a sufficiently high frequency may provide useful data for the evaluation of borehole wall formations in exploration and production wells. An experimental program carried out between 1960 and 1967 on sandstone and limestone samples lent further support to these expectations. At frequencies above 20 Mc/s both real and imaginary parts of the complex epsilon* = epsilon' - j epsilon'' were measurable. Moreover, at higher frequencies, epsilon' proved to be independent of the salinity of the water filling the pores, and insensitive to the way in which the oil and the water are actually distributed. The value of epsilon'', on the other hand, turned out to be indicative of the prevailing salinity. By combining other logging data (for instance from an electric or porosity log) with a series of such v.h.f. measurements of epsilon' and epsilon'', the oil or water saturation, the effective formation porosity, the pore-filling fluid salinity, and the rock matrix formation factor might be deduced, if the depth of investigation can be made large enough to overcome the invasion effects.

  2. Internal fire protection analysis for the United Kingdom EPR design

    Energy Technology Data Exchange (ETDEWEB)

    Laid, Abdallah [Nuclear New Build Generation Company Ltd. (NNB GenCo), Barnwood (United Kingdom). EDF Energy Plc.; Cesbron, Mickael [Service Etudes et Project Thermiques et Nucleaires (SEPTEN), Lyon (France). EDF-SA

    2015-12-15

    In the deterministic design basis analysis of the United Kingdom (UK) EPR based nuclear power plants all postulated initiating events are grouped into two different types, internal faults and internal/external hazards. ''Internal Fires'' is one of the internal hazards analysed at the design stage of the UK EPR. In effect, the main safety objective for fire protection is to ensure that all the required safety functions are performed in the event of an internal fire. To achieve this safety objective, provisions for protection against fire risks are taken to: (i) limit the spread of a fire, protect the safety functions of the facility; (ii) limit the propagation of smoke and dispersion of toxic, radioactive, inflammable, corrosive or explosive materials, and (iii) ensure the achievement of a safe shutdown state, personnel evacuation and all other necessary emergency actions. This paper presents the UK EPR approach on how the above provisions are applied. Such provisions involve implementing means of fire prevention, surveillance, firefighting and limiting fire consequences, appropriate to the risks inherent to the facility. Overall, the design of the UK EPR fire protection systems is based on three types of measures: prevention, containment and control.

  3. Alcoholic extraction enables EPR analysis to characterize radiation-induced cellulosic signals in spices.

    Science.gov (United States)

    Ahn, Jae-Jun; Sanyal, Bhaskar; Akram, Kashif; Kwon, Joong-Ho

    2014-11-19

    Different spices such as turmeric, oregano, and cinnamon were γ-irradiated at 1 and 10 kGy. The electron paramagnetic resonance (EPR) spectra of the nonirradiated samples were characterized by a single central signal (g = 2.006), the intensity of which was significantly enhanced upon irradiation. The EPR spectra of the irradiated spice samples were characterized by an additional triplet signal at g = 2.006 with a hyperfine coupling constant of 3 mT, associated with the cellulose radical. EPR analysis on various sample pretreatments in the irradiated spice samples demonstrated that the spectral features of the cellulose radical varied on the basis of the pretreatment protocol. Alcoholic extraction pretreatment produced considerable improvements of the EPR signals of the irradiated spice samples relative to the conventional oven and freeze-drying techniques. The alcoholic extraction process is therefore proposed as the most suitable sample pretreatment for unambiguous detection of irradiated spices by EPR spectroscopy.

  4. The sensitivity analysis of tooth enamel to the absorbed dose for the application to EPR dosimetry

    International Nuclear Information System (INIS)

    Hong, Dae Seok; Lee, Kun Jai; Cho, Young Hwan

    2002-01-01

    Electron Paramagnetic Resonance (EPR) spectroscopy is one of the methods applicable to retrospective dosimetry. The retrospective dosimetry is a process that is a part of dose reconstruction for estimation of exposed dose occurred years before the estimation. Many techniques can be used to the retrospective dosimetry. As a physical method, EPR analysis of biological material measures the quantity of free radicals generated in the material from the interaction of radiation and material. Since the later 80s, in many countries, EPR dosimetry with tooth enamel has been studied and applied for the retrospective dosimetry. In the consideration of the biological materials for EPR dosimetry, human fingernail, hair, bone and tooth are generally considered. The tooth can be separated as enamel, dentine and cementum. Among the three parts, enamel shows the best sensitivity to the absorbed dose and is most widely used. In this study, the characteristics of tooth enamel for EPR dosimetry is examined and experimented. At the experiment, for easy separation, tooth was cut into 4 parts and then each part is treated by ultrasonic vibration in NaOH liquid to reduce mechanically induced noise in the corresponding signal. After the separation of the enamel from dentine, background EPR signal is measured and then radiation-induced EPR spectrum is estimated

  5. Measurement of rotational dynamics by the simultaneous nonlinear analysis of optical and EPR data.

    OpenAIRE

    Hustedt, E J; Cobb, C E; Beth, A H; Beechem, J M

    1993-01-01

    In the preceding companion article in this issue, an optical dye and a nitroxide radical were combined in a new dual function probe, 5-SLE. In this report, it is demonstrated that time-resolved optical anisotropy and electron paramagnetic resonance (EPR) data can be combined in a single analysis to measure rotational dynamics. Rigid-limit and rotational diffusion models for simulating nitroxide EPR data have been incorporated into a general non-linear least-squares procedure based on the Marq...

  6. A meteor head echo analysis algorithm for the lower VHF band

    Directory of Open Access Journals (Sweden)

    J. Kero

    2012-04-01

    Full Text Available We have developed an automated analysis scheme for meteor head echo observations by the 46.5 MHz Middle and Upper atmosphere (MU radar near Shigaraki, Japan (34.85° N, 136.10° E. The analysis procedure computes meteoroid range, velocity and deceleration as functions of time with unprecedented accuracy and precision. This is crucial for estimations of meteoroid mass and orbital parameters as well as investigations of the meteoroid-atmosphere interaction processes. In this paper we present this analysis procedure in detail. The algorithms use a combination of single-pulse-Doppler, time-of-flight and pulse-to-pulse phase correlation measurements to determine the radial velocity to within a few tens of metres per second with 3.12 ms time resolution. Equivalently, the precision improvement is at least a factor of 20 compared to previous single-pulse measurements. Such a precision reveals that the deceleration increases significantly during the intense part of a meteoroid's ablation process in the atmosphere. From each received pulse, the target range is determined to within a few tens of meters, or the order of a few hundredths of the 900 m long range gates. This is achieved by transmitting a 13-bit Barker code oversampled by a factor of two at reception and using a novel range interpolation technique. The meteoroid velocity vector is determined from the estimated radial velocity by carefully taking the location of the meteor target and the angle from its trajectory to the radar beam into account. The latter is determined from target range and bore axis offset. We have identified and solved the signal processing issue giving rise to the peculiar signature in signal to noise ratio plots reported by Galindo et al. (2011, and show how to use the range interpolation technique to differentiate the effect of signal processing from physical processes.

  7. EPR spectrum deconvolution and dose assessment of fossil tooth enamel using maximum likelihood common factor analysis

    International Nuclear Information System (INIS)

    Vanhaelewyn, G.; Callens, F.; Gruen, R.

    2000-01-01

    In order to determine the components which give rise to the EPR spectrum around g = 2 we have applied Maximum Likelihood Common Factor Analysis (MLCFA) on the EPR spectra of enamel sample 1126 which has previously been analysed by continuous wave and pulsed EPR as well as EPR microscopy. MLCFA yielded agreeing results on three sets of X-band spectra and the following components were identified: an orthorhombic component attributed to CO - 2 , an axial component CO 3- 3 , as well as four isotropic components, three of which could be attributed to SO - 2 , a tumbling CO - 2 and a central line of a dimethyl radical. The X-band results were confirmed by analysis of Q-band spectra where three additional isotropic lines were found, however, these three components could not be attributed to known radicals. The orthorhombic component was used to establish dose response curves for the assessment of the past radiation dose, D E . The results appear to be more reliable than those based on conventional peak-to-peak EPR intensity measurements or simple Gaussian deconvolution methods

  8. The Third International Intercomparison on EPR Tooth Dosimetry: Part 2, final analysis

    International Nuclear Information System (INIS)

    Wieser, A.; Debuyst, R.; Fattibene, P.; Meghzifene, A.; Onori, S.; Bayankin, S. N.; Brik, A.; Bugay, A.; Chumak, V.; Ciesielski, B.; Hoshi, M.; Imata, H.; Ivannikov, A.; Ivanov, D.; Junczewska, M.; Miyazawa, C.; Penkowski, M.; Pivovarov, S.; Romanyukha, A.; Romanyukha, L.; Schauer, D.; Scherbina, O.; Schultka, K.; Sholom, S.; Skvortsov, V.; Stepanenko, V.; Thomas, J. A.; Tielewuhan, E.; Toyoda, S.; Trompier, F.

    2006-01-01

    The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation. (authors)

  9. Analysis of the EPR-experiment by relativistic quantum logic

    International Nuclear Information System (INIS)

    Mittelstaedt, P.

    1984-01-01

    The Einstein-Podolsky-Rosen-experiment is analysed in the framework of an abstract language for relativistic quantum physics, which can be founded on the most general possibilities of physical observations and without any recourse to the Hilbert-space formulation of relativistic quantum theory. -Within this approach one obtains nonlocal correlations between the two EPR-systems in accordance with recent experiments and with quantum theory. These correlations can, however, not be used in order to produce superluminal signals and thus to violate Einstein-causality and special relativity. (author)

  10. Time and latitudinal distribution of the ionospheric irregularities in Brazil, through the VHF-scintillation and ionogram data analysis

    International Nuclear Information System (INIS)

    Nelson, O.R.

    1984-01-01

    Equatorial ionospheric irregularity distribution morphology, and dynamics, and the dynamics of the ambient ionosphere were investigated. Spread F data from ionograms over Fortaleza (4 0 S; 38 0 O) and Cachoeira Paulista (22,7 0 S; 45 0 O), and simultaneous VHF scintillations of geoestationary satellite beacon received over Natal (5,6 0 S; 33,7 0 O) were used to determine the irregularity local time versus seasonal distribution, over the equatorial and low latitude location, during the solar activity maximum as well as minimum epochs. Concept of flux tube alignment properties of the transequatorial plasma bubbles were used to determine statistical features of the plasma bubble rise velocities. Calculations of plasma bubble rise velocities were then carried out for different solar activity epochs and compared with prereversal enhancement amplitude in the F-layer vertical rise velocities, for the same epochs. Using theoretical considerations on the development of plasma bubble based on flux tube integrated properties, the observed dependence of the plasma bubble rise velocities and the F-region dynamo electric field has been analysed to estimate the average ionizations depletions in the plasma bubble. Possible causes for the lack of correlation often observed between bubble rise velocities and F-Layer velocities also are discussed. (Author) [pt

  11. Analysis of two-player quantum games in an EPR setting using Clifford's geometric algebra.

    Science.gov (United States)

    Chappell, James M; Iqbal, Azhar; Abbott, Derek

    2012-01-01

    The framework for playing quantum games in an Einstein-Podolsky-Rosen (EPR) type setting is investigated using the mathematical formalism of geometric algebra (GA). The main advantage of this framework is that the players' strategy sets remain identical to the ones in the classical mixed-strategy version of the game, and hence the quantum game becomes a proper extension of the classical game, avoiding a criticism of other quantum game frameworks. We produce a general solution for two-player games, and as examples, we analyze the games of Prisoners' Dilemma and Stag Hunt in the EPR setting. The use of GA allows a quantum-mechanical analysis without the use of complex numbers or the Dirac Bra-ket notation, and hence is more accessible to the non-physicist.

  12. Analysis of two-player quantum games in an EPR setting using Clifford's geometric algebra.

    Directory of Open Access Journals (Sweden)

    James M Chappell

    Full Text Available The framework for playing quantum games in an Einstein-Podolsky-Rosen (EPR type setting is investigated using the mathematical formalism of geometric algebra (GA. The main advantage of this framework is that the players' strategy sets remain identical to the ones in the classical mixed-strategy version of the game, and hence the quantum game becomes a proper extension of the classical game, avoiding a criticism of other quantum game frameworks. We produce a general solution for two-player games, and as examples, we analyze the games of Prisoners' Dilemma and Stag Hunt in the EPR setting. The use of GA allows a quantum-mechanical analysis without the use of complex numbers or the Dirac Bra-ket notation, and hence is more accessible to the non-physicist.

  13. Mechanical design and analysis for a EPR first wall/blanket/shield system

    International Nuclear Information System (INIS)

    Stevens, H.C.; Misra, B.; Youngdahl, C.K.

    1978-01-01

    Continuing studies are in progress at ANL to expand upon the design of a first wall/blanket/shield FW/B/S system and power conversion for a tokamak type Experimental Power Reactor (EPR). The FW/B/S system has evolved from an earlier design for a low beta, circular cross section plasma (major radius = 6 m) to one for a higher beta elongated plasma with a 4.7 m major radius. Basic mechanical design and layout features of the old and new EPR designs showing some of the more important design developments are given. These developments are aimed at simplifying the design, reducing the costs and in addition, improving the plant thermal efficiency and overall maintainability. In the area of the reactor blanket, significant thermal hydraulic and stress analysis have been performed to substantiate the integrity of the chosen concept. This paper deals with the discussion of these improved features

  14. Dihydroazulene/Vinylheptafulvene (DHA/VHF)

    DEFF Research Database (Denmark)

    Vlasceanu, Alexandru

    A theoretical and experimental investigation of conformational modifications on the thermodynamic, optical, and switching properties of dihydroazulene/vinylheptafulvene (DHA/VHF) photoswitches, in the context of molecular solar thermal (MOST) systems, is described herein. The optical properties...... of monomeric DHA/VHF systems are found to be strongly dependent on structural changes which can be tuned via steric modifications. This correlation is then used to infer structural features of more complex, macrocyclic DHA/VHF systems based on their optical properties. The introduction of macrocyclic ring...... strain is furthermore found to significantly influence the switching behavior of DHA/VHF moieties compared to non-cyclized systems. The thermal ring closure of macrocyclic VHF-VHF systems is found to occur in a stepwise manner, enabling the release of the energy on both a fast and slow timescale...

  15. Severe accident analysis to prevent high pressure scenarios in the EPR TM

    International Nuclear Information System (INIS)

    Azarian, G.; Gandrille, P.; Gasperini, M.; Klein, R.

    2010-01-01

    The EPR TM has incorporated several design features in order to specifically address major severe accident safety issues. In particular, it was designed with the objective to transfer high pressure core melt scenarios into a low pressure scenario with high reliability so that a high pressure vessel failure can be practically eliminated. It is the key issue in the defense-in-depth approach, for a postulated severe accident with core melting, to prevent any risk of containment failure due to possible Direct Containment Heating or due to reactor vessel rocketing which results from vessel failure at high pressure. Temperature-induced steam generator tube rupture, which could lead to a radiological containment bypass, has also to be prevented. On the basis of the analysis of the main high pressure core melt scenarios which are calculated with the MAAP4.07 code which was developed to support the EPR TM, this paper explores the benefits of primary depressurization by dedicated valves on transient evolutions. It specifically addresses the thermal response of the structures by sensitivity studies involving the timing of valve actuation. It outlines that a grace period of at least one hour is available for a delayed valve actuation without inducing excessive loads and without increasing the risk of a temperature-induced steam generator tube rupture. (authors)

  16. Electron paramagnetic resonance (EPR) biodosimetry

    International Nuclear Information System (INIS)

    Desrosiers, Marc; Schauer, David A.

    2001-01-01

    Radiation-induced electron paramagnetic resonance (EPR) signals were first reported by Gordy et al. [Proc. Natl. Acad. Sci. USA 41 (1955) 983]. The application of EPR spectroscopy to ionizing radiation dosimetry was later proposed by Brady et al. [Health Phys. 15 (1968) 43]. Since that time EPR dosimetry has been applied to accident and epidemiologic dose reconstruction, radiation therapy, food irradiation, quality assurance programs and archaeological dating. Materials that have been studied include bone, tooth enamel, alanine and quartz. This review paper presents the fundamentals and applications of EPR biodosimetry. Detailed information regarding sample collection and preparation, EPR measurements, dose reconstruction, and data analysis and interpretation will be reviewed for tooth enamel. Examples of EPR biodosimetry application in accidental overexposures, radiopharmaceutical dose assessment and retrospective epidemiologic studies will also be presented

  17. Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

    International Nuclear Information System (INIS)

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

    1999-01-01

    13 C-enriched polyethylene was subjected to γ-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by 13 C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and esters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase

  18. The EPR reactor

    International Nuclear Information System (INIS)

    Lacoste, A.C.; Dupuy, Ph.; Gupta, O.; Perez, J.R.; Emond, D.; Cererino, G.; Rousseau, J.M.; Jeffroy, F.; Evrard, J.M.; Seiler, J.M.; Azarian, G.; Chaumont, B.; Dubail, A.; Fischer, M.; Tiippana, P.; Hyvarinen, J.; Zaleski, C.P.; Meritet, S.; Iglesias, F.; Vincent, C.; Massart, S.; Graillat, G.; Esteve, B.; Mansillon, Y.; Gatinol, C.; Carre, F.

    2005-01-01

    This document reviews economical and environmental aspects of the EPR project. The following topics are discussed: role and point of view of the French Nuclear Safety Authority on EPR, control of design and manufacturing of EPR by the French Nuclear Safety Authority, assessment by IRSN of EPR safety, research and development in support of EPR, STUK safety review of EPR design, standpoint on EPR, the place of EPR in the French energy policy, the place of EPR in EDF strategy, EPR spearhead of nuclear rebirth, the public debate, the local stakes concerning the building of EPR in France at Flamanville (Manche) and the research on fourth generation reactors. (A.L.B.)

  19. γ radiation level simulation and analysis with MCNP in EPR containment during severe accident

    International Nuclear Information System (INIS)

    Zeng Jun; Liu Shuhuan; Wang Yang; Zhai Liang

    2013-01-01

    The γ dosimetry model based on the EPR core structure, material composition and the designed shielding system was established. The γ-ray dose rate distributions in EPR containment under different conditions including normal operation state, loss-of-coolant accident and core melt severe accident were simulated with MCNP5, and the calculation results under normal operation state and severe accident were compared and analyzed respectively with that of the designed limit. The study results may provide some relative data reference for EPR core accident prediction and reactor accident emergency decision making. (authors)

  20. Biomolecular EPR spectroscopy

    CERN Document Server

    Hagen, Wilfred Raymond

    2008-01-01

    Comprehensive, Up-to-Date Coverage of Spectroscopy Theory and its Applications to Biological SystemsAlthough a multitude of books have been published about spectroscopy, most of them only occasionally refer to biological systems and the specific problems of biomolecular EPR (bioEPR). Biomolecular EPR Spectroscopy provides a practical introduction to bioEPR and demonstrates how this remarkable tool allows researchers to delve into the structural, functional, and analytical analysis of paramagnetic molecules found in the biochemistry of all species on the planet. A Must-Have Reference in an Intrinsically Multidisciplinary FieldThis authoritative reference seamlessly covers all important bioEPR applications, including low-spin and high-spin metalloproteins, spin traps and spin lables, interaction between active sites, and redox systems. It is loaded with practical tricks as well as do's and don'ts that are based on the author's 30 years of experience in the field. The book also comes with an unprecedented set of...

  1. Pulsed EPR analysis of tooth enamel samples exposed to UV and {gamma}-radiations

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, M., E-mail: marrale@unipa.it [Dipartimento di Fisica, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN, Catania, Italy and Unita CNISM, Palermo (Italy); Longo, A.; Brai, M. [Dipartimento di Fisica, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN, Catania (Italy) and Unita CNISM, Palermo (Italy); Barbon, A.; Brustolon, M. [Dipartimento di Scienze Chimiche, Universita degli Studi di Padova, Via Marzolo 1, 35131 Padova (Italy); Fattibene, P. [Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy)

    2011-09-15

    The electron paramagnetic resonance (EPR) spectroscopy is widely applied for retrospective dosimetric purposes by means of quantitative detection of radicals in tooth enamel and bone samples. In this work we report a study by cw and pulsed EPR on two samples of human tooth enamel respectively irradiated by UV (254 nm) and {gamma}-exposed. The continuous wave (cw) EPR spectra have shown the usual presence in both samples of two types of CO{sub 2}{sup -} radicals, with axial and orthorombic g tensors. We have obtained the electron spin echo detected EPR (ED-EPR) spectra at 80 K of the two samples, and we have shown that they are suitable to mark the difference between the effects produced by the different irradiations. At low temperature the contribution to the ED-EPR spectrum of the mobile radical with the axial g tensor is still present in the UV irradiated sample, but not in the {gamma}-irradiated one, where its dynamics is too slow to average the g tensor. We have moreover studied the two-pulse electron spin echo decay on varying the microwave power, a well established method for measuring the Instantaneous Diffusion. We have found that the spectral diffusion parameter is almost the same for both radiation types, whereas the Instantaneous Diffusion is significantly larger for {gamma}-exposed samples than for UV irradiated ones. This difference is due to a higher local microscopic concentration of free radicals for samples irradiated with {gamma} photons.

  2. The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis

    International Nuclear Information System (INIS)

    Wieser, A.; Debuyst, R.; Fattibene, P.

    2005-01-01

    The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60 Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose

  3. Longitudinal analysis on utilization of medical document management system in a hospital with EPR implementation.

    Science.gov (United States)

    Kuwata, Shigeki; Yamada, Hitomi; Park, Keunsik

    2011-01-01

    Document management systems (DMS) have widespread in major hospitals in Japan as a platform to digitize the paper-based records being out of coverage by EPR. This study aimed to examine longitudinal trends of actual use of DMS in a hospital in which EPR had been in operation, which would be conducive to planning the further information management system in the hospital. Degrees of utilization of electronic documents and templates with DMS were analyzed based on data extracted from a university-affiliated hospital with EPR. As a result, it was found that the number of electronic documents as well as scanned documents circulating at the hospital tended to increase. The result indicated that replacement of paper-based documents with electronic documents did not occur. Therefore it was anticipated that the need for DMS would continue to increase in the hospital. The methods used this study to analyze the trend of DMS utilization would be applicable to other hospitals with with a variety of DMS implementation, such as electronic storage by scanning documents or paper preservation that is compatible with EPR.

  4. The analysis of the system and structure of UK EPR I and C system

    International Nuclear Information System (INIS)

    Ma Quan; Liu Yanyang; Wu Zhiqiang

    2014-01-01

    Firstly, this paper hold that the I and C system play an important role of the diversity and defense-in-depth in the nuclear power plant. Secondly, the paper introduce the main function and general structure of the I and C system of the UK EPR. Furthermore, the paper analyzed the levels of the defense-in-depth, the independence and diversity of the I and C system. Finally, the paper point out the notable characteristics of the diversity and defense-in-depth in the I and C system design of the UK EPR. We hope this paper will give us some helps during we design the third generation nuclear power plant ourselves. (authors)

  5. CMOS VHF transconductance-C lowpass filter

    NARCIS (Netherlands)

    Nauta, Bram

    1990-01-01

    Experimental results of a VHF CMOS transconductance-C lowpass filter are described. The filter is built with transconductors as published earlier. The cutoff frequency can be tuned from 22 to 98 MHz and the measured filter response is very close to the ideal response

  6. EPR and Bell Locality

    OpenAIRE

    Norsen, Travis

    2004-01-01

    A new formulation of the EPR argument is presented, one which uses John Bell's mathematically precise local causality condition in place of the looser locality assumption which was used in the original EPR paper and on which Niels Bohr seems to have based his objection to the EPR argument. The new formulation of EPR bears a striking resemblance to Bell's derivation of his famous inequalities. The relation between these two arguments -- in particular, the role of EPR as part one of Bell's two-...

  7. Analysis of various modifications in spectra analysis on accuracy of dose reconstructions in EPR dosimetry in tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Ciesielski, B., E-mail: bciesiel@gumed.edu.pl [Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk (Poland); Kaminska, J. [Department of Oncology and Radiotherapy, Medical University of Gdansk, Debinki 7, 80-211 Gdansk (Poland); Emerich, K. [Department of Paediatric Dentistry, Medical University of Gdansk, Orzeszkowej 18, 80-208 Gdansk (Poland)

    2011-09-15

    The results of EPR measurements performed due to our participation in the 4th International Comparison of EPR Dosimetry using tooth enamel were used to analyze the effects of modifications in numerical analysis of the measured spectra on precision and accuracy of reconstructed doses. The studied modifications included effects of: (1) a use of Mn{sup 2+} standard, (2) variations in experimental native background signals of tooth enamel used for dose reconstructions, (3) signal filtration, (4) subtraction of empty tube spectra, and (5) variations in the spectra ranges used for calculations (fitting windows). It was shown, that the use of a Mn standard, for normalization of intensities of the recorded signals in the spectra processing, strongly increased the dosimetric accuracy. The regression lines of the doses reconstructed using different background spectra against nominal doses, obtained without Mn standard, had slopes about 30% higher and their scatter range was about 2 times higher than the same parameters obtained when Mn standard was applied in the spectra processing. Accuracy of the measured doses characterized by root mean square deviations from the nominal doses was 71 mGy for calculations with Mn standard and 241 mGy without normalization to Mn lines. Despite the large beneficial effect of the use of Mn standard on accuracy (root mean square deviations of the data, slope of the regression lines), it did not significantly improve the dosimetry performance characterized by the critical dose and detection limit. The smoothing of the spectra by 9 point filtration resulted in 1.6% increase of the reconstructed doses. The subtraction of empty tube spectrum had no effect on precision and accuracy of the dose reconstruction. The performance parameters were also practically insensitive to a choice of a width of the spectral window used for the analysis, provided it encompassed the {approx}1.6 mT range covering the main peaks of the radiation induced signal in

  8. Analysis of Hydroperoxides in solid Polyethylene by NMR and EPR Spectroscopy

    International Nuclear Information System (INIS)

    Assink, Roger A.; Celina, Mathias C.; Dunbar, Timothy D.; Alam, Todd M.; Clough, Roger Lee; Gillen, Kenneth T.

    2000-01-01

    The authors have shown that the hydroperoxide species in γ-irradiated 13 C-polyethylene can be directly observed by 13 C MAS NMR spectroscopy. The experiment was performed without the need for special sample preparation such as chemical derivatization or dissolution. Annealing experiments were employed to study the thermal decomposition of the hydroperoxide species and to measure an activation energy of 98 kJ/mol. EPR spectroscopy suggests that residual polyenyl and alkylperoxy radicals are predominantly trapped in interracial or crystalline regions, while the peroxy radicals observed after UV-photolysis of hydroperoxides are in amorphous regions

  9. Statistical analysis of fuel failures in large break loss-of-coolant accident (LBLOCA) in EPR type nuclear power plant

    International Nuclear Information System (INIS)

    Arkoma, Asko; Hänninen, Markku; Rantamäki, Karin; Kurki, Joona; Hämäläinen, Anitta

    2015-01-01

    Highlights: • The number of failing fuel rods in a LB-LOCA in an EPR is evaluated. • 59 scenarios are simulated with the system code APROS. • 1000 rods per scenario are simulated with the fuel performance code FRAPTRAN-GENFLO. • All the rods in the reactor are simulated in the worst scenario. • Results suggest that the regulations set by the Finnish safety authority are met. - Abstract: In this paper, the number of failing fuel rods in a large break loss-of-coolant accident (LB-LOCA) in EPR-type nuclear power plant is evaluated using statistical methods. For this purpose, a statistical fuel failure analysis procedure has been developed. The developed method utilizes the results of nonparametric statistics, the Wilks’ formula in particular, and is based on the selection and variation of parameters that are important in accident conditions. The accident scenario is simulated with the coupled fuel performance – thermal hydraulics code FRAPTRAN-GENFLO using various parameter values and thermal hydraulic and power history boundary conditions between the simulations. The number of global scenarios is 59 (given by the Wilks’ formula), and 1000 rods are simulated in each scenario. The boundary conditions are obtained from a new statistical version of the system code APROS. As a result, in the worst global scenario, 1.2% of the simulated rods failed, and it can be concluded that the Finnish safety regulations are hereby met (max. 10% of the rods allowed to fail)

  10. Statistical analysis of fuel failures in large break loss-of-coolant accident (LBLOCA) in EPR type nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Arkoma, Asko, E-mail: asko.arkoma@vtt.fi; Hänninen, Markku; Rantamäki, Karin; Kurki, Joona; Hämäläinen, Anitta

    2015-04-15

    Highlights: • The number of failing fuel rods in a LB-LOCA in an EPR is evaluated. • 59 scenarios are simulated with the system code APROS. • 1000 rods per scenario are simulated with the fuel performance code FRAPTRAN-GENFLO. • All the rods in the reactor are simulated in the worst scenario. • Results suggest that the regulations set by the Finnish safety authority are met. - Abstract: In this paper, the number of failing fuel rods in a large break loss-of-coolant accident (LB-LOCA) in EPR-type nuclear power plant is evaluated using statistical methods. For this purpose, a statistical fuel failure analysis procedure has been developed. The developed method utilizes the results of nonparametric statistics, the Wilks’ formula in particular, and is based on the selection and variation of parameters that are important in accident conditions. The accident scenario is simulated with the coupled fuel performance – thermal hydraulics code FRAPTRAN-GENFLO using various parameter values and thermal hydraulic and power history boundary conditions between the simulations. The number of global scenarios is 59 (given by the Wilks’ formula), and 1000 rods are simulated in each scenario. The boundary conditions are obtained from a new statistical version of the system code APROS. As a result, in the worst global scenario, 1.2% of the simulated rods failed, and it can be concluded that the Finnish safety regulations are hereby met (max. 10% of the rods allowed to fail)

  11. Overview of LBB implementation for the EPR

    International Nuclear Information System (INIS)

    Cauquelin, C.

    1997-01-01

    This paper presents an overview of the use of leak-before-break (LBB) analysis for EPR reactors. EPR is an evolutionary Nuclear Island of the 4 loop x 1500 Mwe class currently in the design phase. Application of LBB to the main coolant lines and resulting design impacts are summarized. Background information on LBB analysis in France and Germany is also presented

  12. Overview of LBB implementation for the EPR

    Energy Technology Data Exchange (ETDEWEB)

    Cauquelin, C.

    1997-04-01

    This paper presents an overview of the use of leak-before-break (LBB) analysis for EPR reactors. EPR is an evolutionary Nuclear Island of the 4 loop x 1500 Mwe class currently in the design phase. Application of LBB to the main coolant lines and resulting design impacts are summarized. Background information on LBB analysis in France and Germany is also presented.

  13. Centers responsible for the TL peaks of willemite mineral estimated by EPR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gundu Rao, T.K. [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, São Paulo, SP (Brazil); Cano, Nilo F., E-mail: nilo.cano@unifesp.br [Departamento de Ciências do Mar, Universidade Federal de São Paulo, Rua Doutor Carvalho de Mendonça, 144, CEP 11070-102, Santos, SP (Brazil); Silva-Carrera, Betzabel N.; Ferreira, Reinaldo M. [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, São Paulo, SP (Brazil); Javier-Ccallata, Henry S., E-mail: henrysjc@gmail.com [Escuela Profesional de Física, Facultad de Ciencias Naturales y Formales, Universidad Nacional de San Agustín (UNSA), Av. Independencia S/N, Arequipa (Peru); Watanabe, Shigueo, E-mail: watanabe@if.usp.br [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, São Paulo, SP (Brazil)

    2016-09-15

    The mineral willemite (Zn{sub 2}SiO{sub 4}) exhibits five thermoluminescence (TL) peaks approximately at 160, 225, 260, 310 and 400 °C. Electron paramagnetic resonance (EPR) studies were carried out to study the defect centers induced in the mineral by gamma irradiation and also to identify the centers responsible for the TL process. Room temperature EPR spectrum of irradiated mineral is a superposition of at least four distinct centers. One of the centers (center I) with an isotropic g factor 2.0114 is attributable to an intrinsic O{sup −} type center and the center correlates with the TL peak at 160 °C. Center II exhibiting hyperfine lines is also tentatively assigned to an O{sup −} ion and is related to the low temperature TL peak at 160 °C. Center III is characterized by an axially symmetric g-tensor with principal values g{sub ||}=2.0451 and g{sub ⊥}=2.011 and is identified as an O{sub 2}{sup −} ion. This center appears to be related to 160, 225 and 260 °C TL peaks. Center IV with principal g-values g{sub ||}=2.0025 and g{sub ⊥}=2.0088 is attributed to an F{sup +}-type center (singly ionized oxygen vacancy) and is the likely recombination center for TL peaks between 160 and 310 °C.

  14. EPR-based material modelling of soils

    Science.gov (United States)

    Faramarzi, Asaad; Alani, Amir M.

    2013-04-01

    In the past few decades, as a result of the rapid developments in computational software and hardware, alternative computer aided pattern recognition approaches have been introduced to modelling many engineering problems, including constitutive modelling of materials. The main idea behind pattern recognition systems is that they learn adaptively from experience and extract various discriminants, each appropriate for its purpose. In this work an approach is presented for developing material models for soils based on evolutionary polynomial regression (EPR). EPR is a recently developed hybrid data mining technique that searches for structured mathematical equations (representing the behaviour of a system) using genetic algorithm and the least squares method. Stress-strain data from triaxial tests are used to train and develop EPR-based material models for soil. The developed models are compared with some of the well-known conventional material models and it is shown that EPR-based models can provide a better prediction for the behaviour of soils. The main benefits of using EPR-based material models are that it provides a unified approach to constitutive modelling of all materials (i.e., all aspects of material behaviour can be implemented within a unified environment of an EPR model); it does not require any arbitrary choice of constitutive (mathematical) models. In EPR-based material models there are no material parameters to be identified. As the model is trained directly from experimental data therefore, EPR-based material models are the shortest route from experimental research (data) to numerical modelling. Another advantage of EPR-based constitutive model is that as more experimental data become available, the quality of the EPR prediction can be improved by learning from the additional data, and therefore, the EPR model can become more effective and robust. The developed EPR-based material models can be incorporated in finite element (FE) analysis.

  15. EPR STUDIES OF THERMALLY STERILIZED VASELINUM ALBUM.

    Science.gov (United States)

    Ramos, Paweł; Pilawa, Barbara

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used for examination of free radicals in thermally treated vaselinum album (VA). Thermal treatment in hot air as sterilization process was tested. Conditions of thermal sterilization were chosen according to the pharmaceutical norms. Vaselinum album was heated at the following conditions (T--temperature, t--time): T = 160°C and t = 120 min, T = 170°C and t = 60 min and T = 180°C and t = 30 min. The aim of this work was to determine concentration and free radical properties of thermally sterilized VA. EPR analysis for VA was done 15 min after sterilization. EPR measurements were done at room temperature. EPR spectra were recorded in the range of microwave power of 2.2-70 mW. g-Factor, amplitudes (A) and line width (ΔBpp) of the spectra were determined. The shape of the EPR spectra was analyzed. Free radical concentration (N) in the heated samples was determined. EPR spectra were not obtained for the non heated VA. EPR spectra were detected for all thermally sterilized samples. The spectra revealed complex character, their asymmetry depends on microwave power. The lowest free radicals concentration was found for the VA sterilized at 180°C during 30 min. EPR spectroscopy is proposed as the method useful for optimization of sterilization process of drugs.

  16. VHF Scintillation in an Artificially Heated Ionosphere

    Science.gov (United States)

    Suszcynsky, D. M.; Layne, J.; Light, M. E.; Pigue, M. J.; Rivera, L.

    2017-12-01

    As part of an ongoing project to characterize very-high-frequency (VHF) radio wave propagation through structured ionospheres, Los Alamos National Laboratory has been conducting a set of experiments to measure the scintillation effects of VHF transmissions under a variety of ionospheric conditions. Previous work (see 2015 Fall AGU poster by D. Suszcynsky et al.) measured the S4 index and ionospheric coherence bandwidth in the 32 - 44 MHz frequency range under naturally scintillated conditions in the equatorial region at Kwajalein Atoll during three separate campaigns centered on the 2014 and 2015 equinoxes. In this paper, we will present preliminary results from the February and September, 2017 High Altitude Auroral Research Project (HAARP) Experimental Campaigns where we are attempting to make these measurements under more controlled conditions using the HAARP ionospheric heater in a twisted-beam mode. Two types of measurements are made by transmitting VHF signals through the heated ionospheric volume to the Radio Frequency Propagation (RFProp) satellite experiment. The S4 scintillation index is determined by measuring the power fluctuations of a 135-MHz continuous wave signal and the ionospheric coherence bandwidth is simultaneously determined by measuring the delay spread of a frequency-modulated continuous wave (FMCW) signal in the 130 - 140 MHz frequency range. Additionally, a spatial Fourier transform of the CW time series is used to calculate the irregularity spectral density function. Finally, the temporal evolution of the time series is used to characterize spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities. All results are compared to theory and scaled for comparison to the 32 - 44 MHz Kwajalein measurements.

  17. Heat Transfer Analysis of the European Pressurized Water Reactor (EPR) Core Catcher Test Facility Volley

    Energy Technology Data Exchange (ETDEWEB)

    Pikkarainen, Mika; Laine, Jani; Purhonen, Heikki; Kyrki-Rajamaeki, Riitta [Lappeenranta University of Technology, P.O. 20 53851 Lappeenranta (Finland); Sairanen, Risto [Radiation and Nuclear Safety Authority, P.O. 14 00881 Helsinki (Finland)

    2008-07-01

    The EPR is designed to cope with severe accidents, involving core meltdown. A specific melt spreading area has been designed within the containment. This core catcher will be flooded by water, which transfers the decay heat to the containment heat removal system. To improve cooling, horizontal flow channels made of cast iron are located also below the core catcher. STUK, the radiation and nuclear safety authority in Finland, wanted an independent study of the functionality of the core catcher design. Effect of the presence of insulation material and boric acid in the cooling water was to be studied, as well as the general behavior of the system in different phases of the flooding of the core melt spreading area. To verify the function of the core catcher design, a scaled down test facility was built at Lappeenranta University of Technology. Since there are some physical restrictions of a test facility computational tools were applied especially for the tests where steady state conditions could not be reached without endangering the integrity of the test facility. This paper introduces the Volley test facility, computational simulations and compares them with the test results. Simulated temperatures of those Volley tests, which could be run until steady state conditions, are very close to the measured temperatures. It can be concluded also, that the temperatures are evidently below the cast iron melting point with heat fluxes used in the tests, if there is a small flow inside the cooling channels or even in case when only a few adjacent cooling channels are totally dry. (authors)

  18. Heat Transfer Analysis of the European Pressurized Water Reactor (EPR) Core Catcher Test Facility Volley

    International Nuclear Information System (INIS)

    Pikkarainen, Mika; Laine, Jani; Purhonen, Heikki; Kyrki-Rajamaeki, Riitta; Sairanen, Risto

    2008-01-01

    The EPR is designed to cope with severe accidents, involving core meltdown. A specific melt spreading area has been designed within the containment. This core catcher will be flooded by water, which transfers the decay heat to the containment heat removal system. To improve cooling, horizontal flow channels made of cast iron are located also below the core catcher. STUK, the radiation and nuclear safety authority in Finland, wanted an independent study of the functionality of the core catcher design. Effect of the presence of insulation material and boric acid in the cooling water was to be studied, as well as the general behavior of the system in different phases of the flooding of the core melt spreading area. To verify the function of the core catcher design, a scaled down test facility was built at Lappeenranta University of Technology. Since there are some physical restrictions of a test facility computational tools were applied especially for the tests where steady state conditions could not be reached without endangering the integrity of the test facility. This paper introduces the Volley test facility, computational simulations and compares them with the test results. Simulated temperatures of those Volley tests, which could be run until steady state conditions, are very close to the measured temperatures. It can be concluded also, that the temperatures are evidently below the cast iron melting point with heat fluxes used in the tests, if there is a small flow inside the cooling channels or even in case when only a few adjacent cooling channels are totally dry. (authors)

  19. A novel microfluidic rapid freeze-quench device for trapping reactions intermediates for high field EPR analysis.

    Science.gov (United States)

    Kaufmann, Royi; Yadid, Itamar; Goldfarb, Daniella

    2013-05-01

    Rapid freeze quench electron paramagnetic resonance (RFQ)-EPR is a method for trapping short lived intermediates in chemical reactions and subjecting them to EPR spectroscopy investigation for their characterization. Two (or more) reacting components are mixed at room temperature and after some delay the mixture is sprayed into a cold trap and transferred into the EPR tube. A major caveat in using commercial RFQ-EPR for high field EPR applications is the relatively large amount of sample needed for each time point, a major part of which is wasted as the dead volume of the instrument. The small sample volume (∼2μl) needed for high field EPR spectrometers, such as W-band (∼3.5T, 95GHz), that use cavities calls for the development of a microfluidic based RFQ-EPR apparatus. This is particularly important for biological applications because of the difficulties often encountered in producing large amounts of intrinsically paramagnetic proteins and spin labeled nucleic acid and proteins. Here we describe a dedicated microfluidic based RFQ-EPR apparatus suitable for small volume samples in the range of a few μl. The device is based on a previously published microfluidic mixer and features a new ejection mechanism and a novel cold trap that allows collection of a series of different time points in one continuous experiment. The reduction of a nitroxide radical with dithionite, employing the signal of Mn(2+) as an internal standard was used to demonstrate the performance of the microfluidic RFQ apparatus. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. 2D FTIR correlation spectroscopy and EPR analysis of Urtica dioica leaves from areas of different environmental pollution.

    Science.gov (United States)

    Moskal, Paulina; Wesełucha-Birczyńska, Aleksandra; Łabanowska, Maria; Kurdziel, Magdalena; Filek, Maria

    2018-01-15

    Leaves of Urtica dioica collected from two areas of different environmental pollution were analysed by fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR) spectroscopy. Analysis of FTIR spectra allows to describe main component of plant like proteins, lipids and carbohydrates. Although the FTIR spectra of plants from these two geographical locations of different environmental pollution appear to be relatively similar, 2D correlation shows completely different patterns. Synchronous and asynchronous correlation maps showed sequences of changes occurring during development of plant, manly in Amide I and Amide II, lignin, lipids and cellulose. In addition, 2D analysis revealed another sequence of changes as the function of plant growth depending on the degree of the environmental pollution. Two various kinds of paramagnetic species, transition metal ions (Mn(II), Fe(III)) and stable organic radicals (chlorophyll, semiquinone, tyrosyl and carbon centered) were found in leaves of nettle collected at different stages of development and growing in clean and polluted environment. In plants growing in polluted area the injuries of protein molecules bonding metal ions and the disturbances of photosynthesis and redox equilibrium in cells, as well as instability of polysaccharide structure of cell walls were observed. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. 2D FTIR correlation spectroscopy and EPR analysis of Urtica dioica leaves from areas of different environmental pollution

    Science.gov (United States)

    Moskal, Paulina; Wesełucha-Birczyńska, Aleksandra; Łabanowska, Maria; Kurdziel, Magdalena; Filek, Maria

    2018-01-01

    Leaves of Urtica dioica collected from two areas of different environmental pollution were analysed by fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR) spectroscopy. Analysis of FTIR spectra allows to describe main component of plant like proteins, lipids and carbohydrates. Although the FTIR spectra of plants from these two geographical locations of different environmental pollution appear to be relatively similar, 2D correlation shows completely different patterns. Synchronous and asynchronous correlation maps showed sequences of changes occurring during development of plant, manly in Amide I and Amide II, lignin, lipids and cellulose. In addition, 2D analysis revealed another sequence of changes as the function of plant growth depending on the degree of the environmental pollution. Two various kinds of paramagnetic species, transition metal ions (Mn(II), Fe(III)) and stable organic radicals (chlorophyll, semiquinone, tyrosyl and carbon centered) were found in leaves of nettle collected at different stages of development and growing in clean and polluted environment. In plants growing in polluted area the injuries of protein molecules bonding metal ions and the disturbances of photosynthesis and redox equilibrium in cells, as well as instability of polysaccharide structure of cell walls were observed.

  2. Note related to the examination of fitness to service of the vessel bottom and cover of the Flamanville EPR reactor. Pedagogical sheet: Analysis of consequences of the fabrication anomaly of the Flamanville EPR reactor vessel bottom and cover

    International Nuclear Information System (INIS)

    2017-01-01

    After having recalled the context related to the discovery of a fabrication anomaly in the chemical composition of the steel used in the central part of the vessel cover and bottom of the Flamanville EPR reactor, this report presents the approach proposed and adopted by Areva for the justification of the mechanical strength of the vessel cover and bottom. It indicates the main conclusions of the IRSN and ASN on various issues addressed by the audit performed by AREVA: fabrication controls, material characterisation, thermal-mechanical loadings, mechanical analysis of a risk of sudden failure. The next part proposes a pedagogical sheet of consequences of a fabrication anomaly: presentation of vessel structure and specificities, report of the discovery of this anomaly and main consequence (steel embrittlement), expertise approach, expertise conclusions (control of the absence of any deleterious defect, characterisation of material mechanical properties, assessment of thermal-mechanical loadings, assessment of a risk of sudden failure, and in-service follow-up)

  3. Analysis of SCRM experience in the area of quality assurance for retrospective EPR dosimetry technique with teeth

    International Nuclear Information System (INIS)

    Sholom, S. V.; Chumak, V.V.

    2003-01-01

    EPR dosimetry with tooth enamel is commonly accepted as one of most precise and accurate methods for retrospective dosimetry. At the same time, regularly conducted international Intercomparisons and Inter-calibrations of EPR dosimetry techniques demonstrate the significant scatter of results among laboratories operation in this area. This is mainly caused by the lack of commonly adopted unified technique which would be based on clear and efficient scheme of quality assurance. In the present work we will summarize more than ten-year experience of Scientific Center for Radiation Medicine in the area of EPR dosimetry from the point of view of quality assurance. EPR dosimetry technique with teeth, which was developed and being used in SCRM for routine dosimetry of liquidators is characterized by two-level system of quality assurance. In-house level covers all steps of the technique and allows control and minimizing of uncertainties that arise on separate steps. Extramural level provides the control of reliability and accuracy of technique in whole by means of regular participation in bi- and multi-lateral intercomparisons. Cumulative uncertainty of EPR dosimetry technique determined based on the results of 6 different intercomparisons is 21 mGy for dose below 300 and 11% for dose higher that 300 mGy. (authors)

  4. Observation of a tropopause fold by MARA VHF wind-profiler radar and ozonesonde at Wasa, Antarctica: comparison with ECMWF analysis and a WRF model simulation

    Directory of Open Access Journals (Sweden)

    M. Mihalikova

    2012-09-01

    Full Text Available Tropopause folds are one of the mechanisms of stratosphere–troposphere exchange, which can bring ozone rich stratospheric air to low altitudes in the extra-tropical regions. They have been widely studied at northern mid- or high latitudes, but so far almost no studies have been made at mid- or high southern latitudes. The Moveable Atmospheric Radar for Antarctica (MARA, a 54.5 MHz wind-profiler radar, has operated at the Swedish summer station Wasa, Antarctica (73° S, 13.5° W during austral summer seasons from 2007 to 2011 and has observed on several occasions signatures similar to those caused by tropopause folds at comparable Arctic latitudes. Here a case study is presented of one of these events when an ozonesonde successfully sampled the fold. Analysis from European Center for Medium Range Weather Forecasting (ECMWF is used to study the circumstances surrounding the event, and as boundary conditions for a mesoscale simulation using the Weather Research and Forecasting (WRF model. The fold is well resolved by the WRF simulation, and occurs on the poleward side of the polar jet stream. However, MARA resolves fine-scale layering associated with the fold better than the WRF simulation.

  5. N-tert-butylmethanimine N-oxide is an efficient spin-trapping probe for EPR analysis of glutathione thiyl radical

    Science.gov (United States)

    Scott, Melanie J.; Billiar, Timothy R.; Stoyanovsky, Detcho A.

    2016-01-01

    The electron spin resonance (EPR) spin-trapping technique allows detection of radical species with nanosecond half-lives. This technique is based on the high rates of addition of radicals to nitrones or nitroso compounds (spin traps; STs). The paramagnetic nitroxides (spin-adducts) formed as a result of reactions between STs and radical species are relatively stable compounds whose EPR spectra represent “structural fingerprints” of the parent radical species. Herein we report a novel protocol for the synthesis of N-tert-butylmethanimine N-oxide (EBN), which is the simplest nitrone containing an α-H and a tertiary α′-C atom. We present EPR spin-trapping proof that: (i) EBN is an efficient probe for the analysis of glutathione thiyl radical (GS•); (ii) β-cyclodextrins increase the kinetic stability of the spin-adduct EBN/•SG; and (iii) in aqueous solutions, EBN does not react with superoxide anion radical (O2−•) to form EBN/•OOH to any significant extent. The data presented complement previous studies within the context of synthetic accessibility to EBN and efficient spin-trapping analysis of GS•. PMID:27941944

  6. Medical application of EPR

    International Nuclear Information System (INIS)

    Eichhoff, Uwe; Hoefer, Peter

    2015-01-01

    Selected applications of continuous-wave EPR in medicine are reviewed. This includes detection of reactive oxygen and nitrogen species, pH measurements and oxymetry. Applications of EPR imaging are demonstrated on selected examples and future developments to faster imaging methods are discussed

  7. Environmental/Noise Effects on VHF/UHF UWB SAR

    National Research Council Canada - National Science Library

    Ralston, James

    1998-01-01

    This paper presents a straightforward approach to estimating the impact of natural environmental noise on an overall system noise temperature for very high frequency/ultrahigh frequency synthetic aperture radar (VHF/UHF SAR...

  8. Dicty_cDB: VHF145 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VH (Link to library) VHF145 (Link to dictyBase) - - - Contig-U15430-1 VHF145E (Link...) Clone ID VHF145 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15430-1 Ori...ology vs DNA Score E Sequences producing significant alignments: (bits) Value N AC116984 |AC116984.2 Dictyos... theta DNA for complete sequence of nucleomorph chromosome 2. 48 2e-07 2 ES451909 | PREDICTED: similar to PI...al 16.0 %: nuclear 8.0 %: vacuolar 8.0 %: endoplasmic reticulum 4.0 %: cytoskeletal >> prediction for VHF145

  9. One-way EPR steering and genuine multipartite EPR steering

    Science.gov (United States)

    He, Qiongyi; Reid, Margaret D.

    2012-11-01

    We propose criteria and experimental strategies to realise the Einstein-Podolsky-Rosen (EPR) steering nonlocality. One-way steering can be obtained where there is asymmetry of thermal noise on each system. We also present EPR steering inequalities that act as signatures and suggest how to optimise EPR correlations in specific schemes so that the genuine multipartite EPR steering nonlocality (EPR paradox) can also possibly be realised. The results presented here also apply to the spatially separated macroscopic atomic ensembles.

  10. EPR: Evidence and fallacy.

    Science.gov (United States)

    Nichols, Joseph W; Bae, You Han

    2014-09-28

    The enhanced permeability and retention (EPR) of nanoparticles in tumors has long stood as one of the fundamental principles of cancer drug delivery, holding the promise of safe, simple and effective therapy. By allowing particles preferential access to tumors by virtue of size and longevity in circulation, EPR provided a neat rationale for the trend toward nano-sized drug carriers. Following the discovery of the phenomenon by Maeda in the mid-1980s, this rationale appeared to be well justified by the flood of evidence from preclinical studies and by the clinical success of Doxil. Clinical outcomes from nano-sized drug delivery systems, however, have indicated that EPR is not as reliable as previously thought. Drug carriers generally fail to provide superior efficacy to free drug systems when tested in clinical trials. A closer look reveals that EPR-dependent drug delivery is complicated by high tumor interstitial fluid pressure (IFP), irregular vascular distribution, and poor blood flow inside tumors. Furthermore, the animal tumor models used to study EPR differ from clinical tumors in several key aspects that seem to make EPR more pronounced than in human patients. On the basis of this evidence, we believe that EPR should only be invoked on a case-by-case basis, when clinical evidence suggests the tumor type is susceptible. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The EPR paradox revisited

    International Nuclear Information System (INIS)

    Cantrell, C.D.; Scully, M.O.

    1978-01-01

    Einstein, Podolsky and Rosen (EPR) argued in 1935 that quantum mechanics fails to give an adequate description of physical reality, and also cannot give a consistent wave-function description of certain phenomena. The authors show that a calculation based upon the reduced density matrix removes the formal inconsistency pointed out by EPR. The spirit of the present paper is that of a pedagogical review. (Auth.)

  12. EPR paradox revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, C.D.; Scully, M.O.

    1978-07-01

    Einstein, Podolsky, and Rosen (EPR) argued in 1935 that quantum mechanics fails to give an adequate description of physical reality, and also cannot give a consistent wave-function description of certain phenomena. It is shown that a calculation based upon the reduced density matrix removes the formal inconsistency pointed out by EPR. The spirit of the present paper is that of a pedagogical review.

  13. Retrospective individual dosimetry using EPR of tooth enamel

    International Nuclear Information System (INIS)

    Skvortzo, V.; Ivannikov, A.; Stepanenko, V.; Wieser, A.; Bougai, A.; Brick, A.; Chumak, V.; Radchuk, V.; Repin, V.; Kirilov, V.

    1996-01-01

    The results of joint investigations (in the framework of ECP-10 program) aimed on the improvement of the sensitivity and accuracy of the procedure of dose measurement using tooth enamel EPR spectroscopy are presented. It is shown, what the sensitivity of method may be increased using special physical-chemical procedure of the enamel samples treatment, which leads to the reducing of EPR signal of organic components in enamel. Tooth diseases may have an effect on radiation sensitivity of enamel. On the basis of statistical analysis of the results of more then 2000 tooth enamel samples measurements it was shown, what tooth enamel EPR spectroscopy gives opportunity to register contribution into total dose, which is caused by natural environmental radiation and by radioactive contamination. EPR response of enamel to ultraviolet exposure is investigated and possible influences to EPR dosimetry is discussed. The correction factors for EPR dosimetry in real radiation fields are estimated

  14. Discharge Characteristic of VHF-DC Superimposed Magnetron Sputtering System

    Science.gov (United States)

    Toyoda, Hirotaka; Fukuoka, Yushi; Fukui, Takashi; Takada, Noriharu; Sasai, Kensuke

    2014-10-01

    Magnetron plasmas are one of the most important tools for sputter deposition of thin films. However, energetic particles from the sputtered target such as backscattered rare gas atoms or oxygen negative ions from oxide targets sometimes induce physical and chemical damages as well as surface roughening to the deposited film surface during the sputtering processes. To suppress kinetic energy of such particles, superposition of RF or VHF power to the DC power has been investigated. In this study, influence of the VHF power superposition on the DC target voltage, which is important factor to determine kinetic energy of high energy particles, is investigated. In the study, 40 MHz VHF power was superimposed to an ITO target and decrease in the target DC voltage was measured as well as deposited film deposition properties such as deposition rate or electrical conductivity. From systematic measurement of the target voltage, it was revealed that the target voltage can be determined by a very simple parameter, i.e., a ratio of VHF power to the total input power (DC and VHF powers) in spite of the DC discharge current. Part of this work was supported by ASTEP, JST.

  15. EPR analysis of biomaterials

    International Nuclear Information System (INIS)

    Sukhodub, L.

    2001-01-01

    There is the review of electron spin resonance application for paramagnetic individual investigation in biomaterials. Especially the bone tissue and tooth enamel can be taken into account. The material composition (e.g. Mn 2+ and Cr 3+ ions) can be measured, also after irradiation (X, γ radiations) when paramagnetic signal appears as a result of physical radiation effects

  16. Identification of gamma-irradiated fruit juices by EPR spectroscopy

    International Nuclear Information System (INIS)

    Aleksieva, K.I.; Dimov, K.G.; Yordanov, N.D.

    2014-01-01

    The results of electron paramagnetic resonance (EPR) study on commercially available juices from various fruits and different fruit contents: 25%, 40%, 50%, and 100%, homemade juices, nectars and concentrated fruit syrups, before and after gamma-irradiation are reported. In order to remove water from non- and irradiated samples all juices and nectars were filtered; the solid residue was washed with alcohol and dried at room temperature. Only concentrated fruit syrups were dried for 60 min at 40 °C in a standard laboratory oven. All samples under study show a singlet EPR line with g=2.0025 before irradiation with exception of concentrated fruit syrups, which are EPR silent. Irradiation of juice samples gives rise to complex EPR spectra which gradually transferred to “cellulose-like” EPR spectrum from 25% to 100% fruit content. Concentrated fruit syrups show typical “sugar-like“ spectra due to added saccharides. All EPR spectra are characteristic and can prove radiation treatment. The fading kinetics of radiation-induced EPR signals were studied for a period of 60 days after irradiation. - Highlights: • The EPR analysis of juices, nectars and syrups proves that the sample has been irradiated. • Two sample preparation procedures were used. • The stability of the radiation induced EPR signals was studied over 2 months. • Application of European standards can be extended for irradiated juices and syrups

  17. VHF signal power suppression in stratiform and convective precipitation

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2006-03-01

    Full Text Available Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer. This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W. Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal suppression.

  18. VHF signal power suppression in stratiform and convective precipitation

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2006-03-01

    Full Text Available Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer.

    This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W. Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal

  19. Using the SLAC VHF and UHF radio systems

    International Nuclear Information System (INIS)

    Struven, W.

    1987-02-01

    The use of the SLAC VHF and UHF Radio Systems and the Tunnel Antenna Systems as they are presently configured is described. The original radio system was built in 1966 and has grown in scope over the years. The Tunnel Antenna Systems were developed for, and first installed in, the PEP ring, and later added to other tunnels and redesigned to cover the UHF range, as well as VHF. The UHF radio system was designed and built for SLC use, and was first used in the SLC Arcs. The three radio systems will be described and the capabilities of each system will be defined

  20. EPR paradox revisited

    Energy Technology Data Exchange (ETDEWEB)

    Klippert, R. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1999-07-01

    In a seminal paper from 1935 Einstein, Podolsky and Rosen produced one of the most powerful weapon against the unpredictability of the world ensured by quantum mechanics. The recent production of entangled states, with all its possible future applications in quantum computation, re-open the possibility of testing EPR states on physical grounds. The present intends to present a challenge to the wedding of classical (special) relativity with quantum mechanics, the so called relativistic quantum mechanics. Making use of the same apparatus devised in EPR, it is shown that non local quantum states are incompatible with either their possibility of being measured or else with Lorentz invariance (or even with both). (author)

  1. EPR spectroscopy of MRI-related Gd(III) complexes: simultaneous analysis of multiple frequency and temperature spectra, including static and transient crystal field effects.

    Science.gov (United States)

    Rast, S; Borel, A; Helm, L; Belorizky, E; Fries, P H; Merbach, A E

    2001-03-21

    For the first time, a very general theoretical method is proposed to interpret the full electron paramagnetic resonance (EPR) spectra at multiple temperatures and frequencies in the important case of S-state metal ions complexed in liquid solution. This method is illustrated by a careful analysis of the measured spectra of two Gd3+ (S = 7/2) complexes. It is shown that the electronic relaxation mechanisms at the origin of the EPR line shape arise from the combined effects of the modulation of the static crystal field by the random Brownian rotation of the complex and of the transient zero-field splitting. A detailed study of the static crystal field mechanism shows that, contrarily to the usual global models involving only second-order terms, the fourth and sixth order terms can play a non-negligible role. The obtained parameters are well interpreted in the framework of the physics of the various underlying relaxation processes. A better understanding of these mechanisms is highly valuable since they partly control the efficiency of paramagnetic metal ions in contrast agents for medical magnetic resonance imaging (MRI).

  2. EPR Dosimetry in Irradiated Fingernails

    International Nuclear Information System (INIS)

    Spinella, M.R.; Dubner, D.L.; Bof, E.

    2010-01-01

    The Electron Paramagnetic Resonance (EPR) is being transformed in a complementary tool of biologically-based methods for evaluation of dose after accidental radiation exposure. Many efforts are being carried out in laboratories to evaluate the performance of different materials for its use in EPR doses measurements and for improving the current methods for spectrum analysis and calibration curves determinations. In our country the EPR techniques have been used in different areas with dosimetric (alanine) and non dosimetric purposes. Now we are performing the first studies to obtain properly dose response curves to be used for accidental dose assessments through irradiated fingernails. It is by now well known that the fingernails present two types of signals, a background one (BKS), originated in elastic and inelastic mechanical deformations and the radio induced one (RIS), object of interest (I). In this work we will present some of the previous studies performed to characterize the fingernail samples and we analyse the additive dose method for data obtained employing the technique of the substraction of the spectrum recorded at two different microwave powers in order to reduce the BKS signal. Fingernail samples collected from different donors were treated by soaking in water during 10 min and 5 min drying on paper towel and the BKS signals were studied previously its irradiation. The statistical analysis (R statistics) show a distribution with a Standard Deviation of 24% respects to its media. During these studies we also conserved in freezer for more than 6 months irradiated fingernails that, were periodically measured and the statistical analysis of the peak to peak amplitude show a normal distribution through the Quantile correlation test with a SD 11% respected to its median. (authors)

  3. EPR analysis of cyanide complexes of wild-type human neuroglobin and mutants in comparison to horse heart myoglobin.

    Science.gov (United States)

    Van Doorslaer, Sabine; Trandafir, Florin; Harmer, Jeffrey R; Moens, Luc; Dewilde, Sylvia

    2014-06-01

    Electron paramagnetic resonance (EPR) data reveal large differences between the ferric ((13)C-)cyanide complexes of wild-type human neuroglobin (NGB) and its H64Q and F28L point mutants and the cyanide complexes of mammalian myo- and haemoglobin. The point mutations, which involve residues comprising the distal haem pocket in NGB, induce smaller, but still significant changes, related to changes in the stabilization of the cyanide ligand. Furthermore, for the first time, the full (13)C hyperfine tensor of the cyanide carbon of cyanide-ligated horse heart myoglobin (hhMb) was determined using Davies ENDOR (electron nuclear double resonance). Disagreement of these experimental data with earlier predictions based on (13)C NMR data and a theoretical model reveal significant flaws in the model assumptions. The same ENDOR procedure allowed also partial determination of the corresponding (13)C hyperfine tensor of cyanide-ligated NGB and H64QNGB. These (13)C parameters differ significantly from those of cyanide-ligated hhMb and challenge our current theoretical understanding of how the haem environment influences the magnetic parameters obtained by EPR and NMR in cyanide-ligated haem proteins. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. EPR: the nuclear impasse

    International Nuclear Information System (INIS)

    Marillier, F.

    2008-01-01

    The questions relative to the climatic change constitute crucial challenges for the next ten years. In this context the author aims to show how the EPR project illustrates the nuclear french ''autism''. He presents and analyzes the international and environmental impacts of this obsolete technology, as a project useless and dangerous. (A.L.B.)

  5. EPR and development of quantum electronics

    International Nuclear Information System (INIS)

    Manenkov, A A

    2011-01-01

    A role of electron paramagnetic resonance in development of quantum electronics is discussed. Basic principles and history of masers are briefly described. Spin-levels of paramagnetic ions in crystals as a very suitable object for active media of solid-state masers (called as EPR-masers) and physical processes in EPR-masers (population inversion of energy states) are analyzed. This analysis demonstrates a significant role of relaxation processes in multi-level spin-systems for efficient maser action. In this context peculiarities of spin-lattice and spin-spin cross relaxation processes in multi-level systems are analyzed. Development of EPR-masers and their application in radioastronomy and far-space communication systems are briefly described.

  6. From VHF to UHF CMOS-MEMS Monolithically Integrated Resonators

    DEFF Research Database (Denmark)

    Teva, Jordi; Berini, Abadal Gabriel; Uranga, A.

    2008-01-01

    This paper presents the design, fabrication and characterization of microresonators exhibiting resonance frequencies in the VHF and UHF bands, fabricated using the available layers of the standard and commercial CMOS technology, AMS-0.35mum. The resonators are released in a post-CMOS process cons...

  7. EPR project construction cost control

    International Nuclear Information System (INIS)

    Duflo, D.; Pouget-Abadie, X.; Dufour, A.; Kauffmann, G.

    2001-01-01

    The EPR project is now managed by EDF in cooperation with the German Utilities. The main engineering activities for this period are related to the preparation of construction project management, deepening of some safety issues, definition of the project technical reference. The EPR project concerns the so-called reference unit, that is an isolated first-off unit, with unit electrical power of about 1500 MW. The construction costs evaluated are those of the nuclear island, the conventional island, site facilities, installation work and the administrative buildings. The EPR project construction cost evaluation method applies to all the equipment installed and commissioned. It requires the availability of a preliminary project detailed enough to identify the bill of quantities. To these quantities are then assigned updated unit prices that are based either on cost bases for similar and recent facilities or taken from request for quotation for similar equipment or result from gains due to contractual conditions benefiting from simplifications in the functional and technical specifications. The input and output data are managed in a model that respects the breakdown on which the evaluation method is based. The structural organization of this method reflects a functional breakdown on the one hand (nuclear island, conventional island, common site elements) and on the other hand a breakdown according to equipment or activity (civil engineering, mechanics, electricity, instrumentation and control). This paper discusses the principle and the method of construction cost evaluation carried out, the cost data base and input and output parameters as well as results and oncoming cost analysis tasks. (author)

  8. Combined VLF and VHF lightning observations of Hurricane Rita landfall

    Science.gov (United States)

    Henderson, B. G.; Suszcynsky, D. M.; Wiens, K. C.; Hamlin, T.; Jeffery, C. A.; Orville, R. E.

    2009-12-01

    Hurricane Rita displayed abundant lightning in its northern eyewall as it made landfall at 0740 UTC 24 Sep 2005 near the Texas/Louisiana border. For this work, we combined VHF and VLF lightning data from Hurricane Rita, along with radar observations from Gulf Coast WSR-88D stations, for the purpose of demonstrating the combined utility of these two spectral regions for hurricane lightning monitoring. Lightning is a direct consequence of the electrification and breakdown processes that take place during the convective stages of thunderstorm development. As Rita approached the Gulf coast, the VHF lightning emissions were distinctly periodic with a period of 1.5 to 2 hours, which is consistent with the rotational period of hurricanes. VLF lightning emissions, measured by LASA and NLDN, were present in some of these VHF bursts but not all of them. At landfall, there was a significant increase in lightning emissions, accompanied by a significant convective surge observed in radar. Furthermore, VLF and VHF lightning source heights clearly increase as a function of time. The evolution of the IC/CG ratio is consistent with that seen in thunderstorms, showing a dominance of IC activity during storm development, followed by an increase in CG activity at the storm’s peak. The periodic VHF lightning events are correlated with increases in convective growth (quantified by the volume of radar echo >40 dB) above 7 km altitude. VLF can discriminate between lightning types, and in the LASA data, Rita landfall lightning activity was dominated by Narrow Bi-polar Events (NBEs)—high-energy, high-altitude, compact intra-cloud discharges. The opportunity to locate NBE lightning sources in altitude may be particularly useful in quantifying the vertical extent (strength) of the convective development and in possibly deducing vertical charge distributions.

  9. EPR: outlines of research and development

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    The articles give an overview of the research and development presently under way for the future pressurized water reactors to be constructed in Europe, and particularly the French and German EPR (European Pressurized Reactor). Such an analysis deals essentially with respect to the pressurized water reactors now in operation. (author)

  10. Can EPR non-locality be geometrical?

    International Nuclear Information System (INIS)

    Ne'eman, Y.

    1995-01-01

    The presence in Quantum Mechanics of non-local correlations is one of the two fundamentally non-intuitive features of that theory. The non-local correlations themselves fall into two classes: EPR and Geometrical. The non-local characteristics of the geometrical type are well-understood and are not suspected of possibly generating acausal features, such as faster-than-light propagation of information. This has especially become true since the emergence of a geometrical treatment for the relevant gauge theories, i.e. Fiber Bundle geometry, in which the quantum non-localities are seen to correspond to pure homotopy considerations. This aspect is reviewed in section 2. Contrary-wise, from its very conception, the EPR situation was felt to be paradoxical. It has been suggested that the non-local features of EPR might also derive from geometrical considerations, like all other non-local characteristics of QM. In[7], one of the authors was able to point out several plausibility arguments for this thesis, emphasizing in particular similarities between the non-local correlations provided by any gauge field theory and those required by the preservation of the quantum numbers of the original EPR state-vector, throughout its spatially-extended mode. The derivation was, however, somewhat incomplete, especially because of the apparent difference between, on the one hand, the closed spatial loops arising in the analysis of the geometrical non-localities, from Aharonov-Bohm and Berry phases to magnetic monopoles and instantons, and on the other hand, in the EPR case, the open line drawn by the positions of the two moving decay products of the disintegrating particle. In what follows, the authors endeavor to remove this obstacle and show that as in all other QM non-localities, EPR is somehow related to closed loops, almost involving homotopy considerations. They develop this view in section 3

  11. EPR (European Pressurized Reactor)

    International Nuclear Information System (INIS)

    2015-01-01

    This document presents the EPR (European Pressurized Reactor), a modernised version of PWRs which uses nuclear fission. It indicates to which category it belongs (third generation). It briefly describes its operation: recalls on nuclear fission, electricity production in a nuclear reactor. It presents and comments its characteristics: power, thermal efficiency, redundant systems for safety control, double protective enclosure, expected lifetime, use of MOX fuel, modular design. It discusses economic stakes (expected higher nuclear electricity competitiveness, but high construction costs), and safety challenges (design characteristics, critics by nuclear safety authorities about the safety data processing system). It presents the main involved actors (Areva, EDF) and competitors in the field of advanced reactors (Rosatom with its VVER 1200, General Electric with its ABWR and its ESBWR, Mitsubishi with its APWR, Westinghouse with its AP100) while outlining the importance of certifications and delays to obtain them. After having evoked key data on EPR fuel consumption, it indicates reactors under construction, evokes potential markets and perspectives

  12. EPR, kvantemekanik og Bohr

    OpenAIRE

    Nielsen, Morten Klockmann

    2007-01-01

    Dette projekt omhandler området hvor filosofi og fysik smelter sammen. Kvantemekanikkens tilblivelse fik en hård medfart hvilket diskussionerne mellem især Albert Einstein og Niels Bohr vidner om. De var hovedpersoner i striden om hvordan kvantemekanikken skulle fortolkes, og diskussionen kulminerede i 1935 hvor Einstein sammen med kollegerne Podolsky og Rosen offentliggjorde en artikel med titlen “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?” (EPR-artiklen)....

  13. EPR a strategic choice

    International Nuclear Information System (INIS)

    2003-01-01

    How can we answer to the increasing demand of electric power, resulting of the demographic evolution and needed to the economic development, without exhausting the fossil resources? The answers are function of the countries and imply an optimization of the production and the consumption. This document published by the Areva Group aims to show the advantages of the nuclear energy: economical and environmental advantages. A special chapter is devoted to the European Pressurized Reactor, EPR. (A.L.B.)

  14. EPR spectroscopy of spices

    Directory of Open Access Journals (Sweden)

    R. T. Тimakova

    2016-01-01

    Full Text Available From 01 January 2017 you enter the interstate standard GOST 33271-2015 “Dry Spices, herbs and vegetable seasonings. Manual exposure in order to combat pathogens and other microorganisms” which States that the absorbed dose of radiation to the spices should be from 3 to 30 kGy. The study found that before the introduction of permissive legislative framework in the consumer market of Russia there are irradiated food products (chili, ground chili, ground spicy chili, black pepper. For radiation monitoring of food safety, we used the method of electron paramagnetic resonance (EPR, which allows quickly and with a high degree of reliability to establish the fact of irradiation. It is established that all samples of spices irradiated with dose of 12 kGy (technology radappertization gave typical spectra of the signals established by the method of electron paramagnetic resonance in the domestic EPR spectrometer, the intensity, amplitude and peak width of the EPR signal of samples of spices with the increase of irradiation dose increases. It is proven that repeated exposure no effect accumulation. Integration with 2017 Russia in the global practi ce of using radiation technologies of processing of food products and food raw materials with the purpose of extending shelf life confirms the need for a data Bank on the radiation sensitivity of various food products to determine the optimal doses and the eff ect of radiation doses on the shelf life and quality of products.

  15. EPR spectroscopy at DNP conditions

    International Nuclear Information System (INIS)

    Heckmann, J.; Goertz, St.; Meyer, W.; Radtke, E.; Reicherz, G.

    2004-01-01

    In terms of dynamic nuclear polarization (DNP) studies and systematic target material research it is crucial to know the EPR lineshape of the DNP relevant paramagnetic centers. Therefore in Bochum an EPR spectrometer has been implemented into the 4 He evaporation DNP facility in order to perform EPR studies at DNP conditions (B=2.5 T, T=1 K). The spectrometer hardware and performance as well as first results are presented

  16. Quantitative EPR A Practitioners Guide

    CERN Document Server

    Eaton, Gareth R; Barr, David P; Weber, Ralph T

    2010-01-01

    This is the first comprehensive yet practical guide for people who perform quantitative EPR measurements. No existing book provides this level of practical guidance to ensure the successful use of EPR. There is a growing need in both industrial and academic research to provide meaningful and accurate quantitative EPR results. This text discusses the various sample, instrument and software related aspects required for EPR quantitation. Specific topics include: choosing a reference standard, resonator considerations (Q, B1, Bm), power saturation characteristics, sample positioning, and finally, putting all the factors together to obtain an accurate spin concentration of a sample.

  17. Security Analysis and Improvement of ‘a More Secure Anonymous User Authentication Scheme for the Integrated EPR Information System’

    Science.gov (United States)

    Islam, SK Hafizul; Khan, Muhammad Khurram; Li, Xiong

    2015-01-01

    Over the past few years, secure and privacy-preserving user authentication scheme has become an integral part of the applications of the healthcare systems. Recently, Wen has designed an improved user authentication system over the Lee et al.’s scheme for integrated electronic patient record (EPR) information system, which has been analyzed in this study. We have found that Wen’s scheme still has the following inefficiencies: (1) the correctness of identity and password are not verified during the login and password change phases; (2) it is vulnerable to impersonation attack and privileged-insider attack; (3) it is designed without the revocation of lost/stolen smart card; (4) the explicit key confirmation and the no key control properties are absent, and (5) user cannot update his/her password without the help of server and secure channel. Then we aimed to propose an enhanced two-factor user authentication system based on the intractable assumption of the quadratic residue problem (QRP) in the multiplicative group. Our scheme bears more securities and functionalities than other schemes found in the literature. PMID:26263401

  18. Security Analysis and Improvement of 'a More Secure Anonymous User Authentication Scheme for the Integrated EPR Information System'.

    Directory of Open Access Journals (Sweden)

    S K Hafizul Islam

    Full Text Available Over the past few years, secure and privacy-preserving user authentication scheme has become an integral part of the applications of the healthcare systems. Recently, Wen has designed an improved user authentication system over the Lee et al.'s scheme for integrated electronic patient record (EPR information system, which has been analyzed in this study. We have found that Wen's scheme still has the following inefficiencies: (1 the correctness of identity and password are not verified during the login and password change phases; (2 it is vulnerable to impersonation attack and privileged-insider attack; (3 it is designed without the revocation of lost/stolen smart card; (4 the explicit key confirmation and the no key control properties are absent, and (5 user cannot update his/her password without the help of server and secure channel. Then we aimed to propose an enhanced two-factor user authentication system based on the intractable assumption of the quadratic residue problem (QRP in the multiplicative group. Our scheme bears more securities and functionalities than other schemes found in the literature.

  19. Investigation of EPR signals on tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Pavlenko, A; Mironova-Ulmane, N; Polakov, M; Riekstina, D [Institute of Solid State Physics, University of Latvia, Riga (Latvia)

    2007-12-15

    Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content.

  20. VHF lightning mapping observations of a triggered lightning flash

    Science.gov (United States)

    Edens, H. E.; Eack, K. B.; Eastvedt, E. M.; Trueblood, J. J.; Winn, W. P.; Krehbiel, P. R.; Aulich, G. D.; Hunyady, S. J.; Murray, W. C.; Rison, W.; Behnke, S. A.; Thomas, R. J.

    2012-10-01

    On 3 August 2010 an extensive lightning flash was triggered over Langmuir Laboratory in New Mexico. The upward positive leader propagated into the storm's midlevel negative charge region, extending over a horizontal area of 13 × 13 km and 7.5 km altitude. The storm had a normal-polarity tripolar charge structure with upper positive charge over midlevel negative charge. Lightning Mapping Array (LMA) observations were used to estimate positive leader velocities along various branches, which were in the range of 1-3 × 104 m s-1, slower than in other studies. The upward positive leader initiated at 3.4 km altitude, but was mapped only above 4.0 km altitude after the onset of retrograde negative breakdown, indicating a change in leader propagation and VHF emissions. The observations suggest that both positive and negative breakdown produce VHF emissions that can be located by time-of-arrival systems, and that not all VHF emissions occurring along positive leader channels are associated with retrograde negative breakdown.

  1. Conformational analysis of the partially disordered measles virus N(TAIL)-XD complex by SDSL EPR spectroscopy.

    Science.gov (United States)

    Kavalenka, Aleh; Urbancic, Iztok; Belle, Valérie; Rouger, Sabrina; Costanzo, Stéphanie; Kure, Sandra; Fournel, André; Longhi, Sonia; Guigliarelli, Bruno; Strancar, Janez

    2010-03-17

    To characterize the structure of dynamic protein systems, such as partly disordered protein complexes, we propose a novel approach that relies on a combination of site-directed spin-labeled electron paramagnetic resonance spectroscopy and modeling of local rotation conformational spaces. We applied this approach to the intrinsically disordered C-terminal domain of the measles virus nucleoprotein (N(TAIL)) both free and in complex with the X domain (XD, aa 459-507) of the viral phosphoprotein. By comparing measured and modeled temperature-dependent restrictions of the side-chain conformational spaces of 12 SL cysteine-substituted N(TAIL) variants, we showed that the 490-500 region of N(TAIL) is prestructured in the absence of the partner, and were able to quantitatively estimate, for the first time to our knowledge, the extent of the alpha-helical sampling of the free form. In addition, we showed that the 505-525 region of N(TAIL) conserves a significant degree of freedom even in the bound form. The latter two findings provide a mechanistic explanation for the reported rather high affinity of the N(TAIL)-XD binding reaction. Due to the nanosecond timescale of X-band EPR spectroscopy, we were also able to monitor the disordering in the 488-525 region of N(TAIL), in particular the unfolding of the alpha-helical region when the temperature was increased from 281 K to 310 K. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  2. EPR design for maintenance

    International Nuclear Information System (INIS)

    Krugmann, U.

    1998-01-01

    Preventive maintenance is very important in achieving high plant availability. For the European Pressurized Reactor (EPR) preventive maintenance has been carefully addressed in the design stage. This is particularly necessary because of the traditionally different maintenance strategies employed in France and Germany. This paper emphasizes the following features introduced in the ERP design to minimize the duration of the refueling outage: (1) containment accessibility during power operation; (2) overall plant layout to facilitate inspections and maintenances within the containment; and (3) safety system design for enabling preventive maintenance during power operation. (author)

  3. First Joint Observations of Radio Aurora by the VHF and HF Radars of the ISTP SB RAS

    Science.gov (United States)

    Berngardt, O. I.; Lebedev, V. P.; Kutelev, K. A.; Kushnarev, D. S.; Grkovich, K. V.

    2018-01-01

    Two modern radars for diagnosis of the ionosphere by the radio-wave backscattering method, namely, the Irkutsk incoherent scatter radar at VHF (IISR, 154-162 MHz) and the Ekaterinburg coherent radar at HF (EKB, 8-20 MHz) are operated at the Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS). The paper analyzes the results of joint observations of strong scattering (radio aurora) on June 8, 2015. To determine the geographical position of the radio aurora, we developed original methods that take into account both the features of the radio-wave propagation and the features of the radar antenna systems. It is shown that there are areas where the spatial position of the HF and VHF radio aurora can coincide. This permits using the radars as a single complex for diagnosis of the characteristics of small-scale high-latitude irregularities in the ionospheric E and F layers. A comparative analysis of the characteristics and temporal dynamics of the radio-aurora region in the HF and VHF ranges is performed. Using the DMSP satellite data, it has been shown that the radio aurora dynamics during this experiment with the EKB radar can be related with the spatial dynamics of the localized area with high electric field, which moves from high to equatorial latitudes. It is found that due to the broader field of view, radio aurora at the HF radar was stably observed 6-12 min earlier than at the VHF radar. This permits using the EKB radar data for prediction of the radio-aurora detection by the IISR radar.

  4. Disturbances in VHF/UHF telemetry links as a possible effect of the 2003 Hokkaido Tokachi-oki earthquake

    Directory of Open Access Journals (Sweden)

    H. Nagamoto

    2008-08-01

    Full Text Available The data on radio telemetry links (for water information at VHF/UHF in Hokkaido are used to investigate the rate of disturbances on radio links (or connection failure and its association with a huge earthquake, Tokachi-oki earthquake on 26 September 2003. Especially, the telemetry links at the Tokachi region closest to the earthquake epicenter, showed a significant increase in disturbances on radio links two weeks to a few days before the earthquake on the basis of analysis during a long interval from 1 June 2002 to 3 November 2007 (over 5 years. We suggest that these severe disturbances in VHF/UHF telemetry links are attributed to the generation of seismogenic VHF/UHF radio noises (emissions. Based on this idea, we have estimated that the intensity of these seismogenic emissions is on the order of 10–19 dB μV/m. Finally, the present result was compared with other physical parameters already obtained for this earthquake.

  5. Which Parts of a Clinical Process EPR Needs Special Configuration

    DEFF Research Database (Denmark)

    Barlach, Anders; Simonsen, Jesper

    2007-01-01

    Subject: Which parts of an electronic patient record (EPR) can initially form a stable standard solution to be used by all clinicians? And which parts of an EPR can we predict needs initial as well as on-going re-configuration to meet the needs from diverse medical specialties. Purpose: To analyze...... which screen types in a clinical process that can be standard configured and which are subject to initial as well as on-going re-configuration. Methods and results: A pilot-project implementing a fully functional clinical process EPR was configured and used at a neurological ward, replacing all paper...... records 24/7. The analysis characterizes the different types of screens, a total of 243 included in the EPR solution. All screens have been extracted from the application and analyzed for changes – in total 222 changes. Discussion and conclusion: Most screens (87%) are very stable. Few (13%) are subjected...

  6. Reconstructing Bohr's Reply to EPR in Algebraic Quantum Theory

    Science.gov (United States)

    Ozawa, Masanao; Kitajima, Yuichiro

    2012-04-01

    Halvorson and Clifton have given a mathematical reconstruction of Bohr's reply to Einstein, Podolsky and Rosen (EPR), and argued that this reply is dictated by the two requirements of classicality and objectivity for the description of experimental data, by proving consistency between their objectivity requirement and a contextualized version of the EPR reality criterion which had been introduced by Howard in his earlier analysis of Bohr's reply. In the present paper, we generalize the above consistency theorem, with a rather elementary proof, to a general formulation of EPR states applicable to both non-relativistic quantum mechanics and algebraic quantum field theory; and we clarify the elements of reality in EPR states in terms of Bohr's requirements of classicality and objectivity, in a general formulation of algebraic quantum theory.

  7. EPR of uranium ions

    International Nuclear Information System (INIS)

    Ursu, I.; Lupei, V.

    1984-02-01

    A review of the electron paramagnetic resonance data on the uranium ions is given. After a general account of the electronic structure of the uranium free atoms and ions, the influence of the external fields (magnetic field, crystal fields) is discussed. The main information obtained from EPR studies on the uranium ions in crystals are emphasized: identification of the valence and of the ground electronic state, determination of the structure of the centers, crystal field effects, role of the intermediate coupling and of the J-mixing, role of the covalency, determination of the nuclear spin, maqnetic dipole moment and electric quadrupole moment of the odd isotopes of uranium. These data emphasize the fact that the actinide group has its own identity and this is accutely manifested at the beginning of the 5fsup(n) series encompassed by the uranium ions. (authors)

  8. Factors influencing EPR dosimetry in fingernails

    International Nuclear Information System (INIS)

    Dubner, D.L.; Spinella, M.R.; Bof, E.

    2010-01-01

    The technique based on the detection of ionizing radiation induced radicals by EPR in tooth enamel is an established method for the dosimetry of exposed persons in radiological emergencies. Dosimetry based on EPR spectral analysis of fingernail clippings, currently under development, has the practical advantage of the easier sample collection. A limiting factor is that overlapping the radiation induced signal (RIS), fingernails have shown the presence of two mechanically induced signals, called MIS1 and MIS2, due to elastic and plastic deformation respectively, at the time of fingernails cutting. With a water treatment, MIS1 is eliminated while MIS2 is considerably reduced. The calibration curves needed for radiation accident dosimetry should have 'universal' characteristics, ie. Represent the variability that can be found in different individuals. Early studies were directed to the analysis of factors affecting the development of such universal calibration curves. The peak to peak amplitude of the signal before and after the water treatment as well as the effect of size and number of clippings were studied. Furthermore, the interpersonal and intrapersonal variability were analyzed. Taking into account these previous studies, the optimal conditions for measurement were determined and EPR spectra of samples irradiated at different doses were used for the developing of dose-response curves. This paper presents the analysis of the results.(authors) [es

  9. EPR in characterization of seeds paramagnetic species

    International Nuclear Information System (INIS)

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C.

    2011-01-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe 2 O 3 ), magnetite (Fe 3 O 4 ), and ferrihydrite (Fe 5 HO 8 · 4H 2 O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn 2+ , which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band (∼ 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe 3+ present in the goethite at g ∼ 2, and in the seeds exist free radicals at g = 2:004, at room temperature

  10. EPR in characterization of seeds paramagnetic species

    Energy Technology Data Exchange (ETDEWEB)

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C. [Universidade Estadual de Londrina (UEL), PR (Brazil)

    2011-07-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), and ferrihydrite (Fe{sub 5}HO{sub 8} {center_dot} 4H{sub 2}O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn{sup 2+}, which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band ({approx} 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe{sup 3+} present in the goethite at g {approx} 2, and in the seeds

  11. Thermodynamic Basis of Electron Transfer in Dihydroorotate Dehydrogenase B from Lactococcus lactis:  Analysis by Potentiometry, EPR Spectroscopy, and ENDOR Spectroscopy

    DEFF Research Database (Denmark)

    Mohnsen, Al-Walid A.; Rigby, Stephen E. J.; Jensen, Kaj Frank

    2004-01-01

    Dihydroorotate dehydrogenase B (DHODB) is a complex iron-sulfur flavoprotein that catalyzes the conversion of dihydroorotate to orotate and the reduction of NAD+. The enzyme is a dimer of heterodimers containing an FMN, an FAD, and a 2Fe-2S center. UV-visible, EPR, and ENDOR spectroscopies have...... similar to those recorded for the blue semiquinone of free flavins in aqueous solution, thus confirming the presence of this species in DHODB. Spectral features observed during EPR spectroscopy of dithionite-reduced DHODB are consistent with the midpoint reduction potentials determined using UV-visible...... spectroscopy and further identify an unusual EPR signal with very small rhombic anisotropy and g values of 2.02, 1.99, and 1.96. This unusual signal is assigned to the formation of a spin interacting state between the FMN semiquinone species and the reduced 2Fe-2S center. Reduction of DHODB using an excess...

  12. EPR Flamanville 3, Site Management

    International Nuclear Information System (INIS)

    Menager, Antoine

    2014-01-01

    Antoine Menager, the EPR Flamanville 3 Site Manager described the organization and the management of the Flamanville site during the construction phase. He placed emphasis on Health and Safety, Environmental and Social Responsibility and on Nuclear Safety and Quality

  13. Repotenciación de un sistema de radiocomunicaciones VHF

    Directory of Open Access Journals (Sweden)

    Juan Ortega

    2016-11-01

    Full Text Available Las comunicaciones móviles avanzan a pasos acelerados, como fuente de ayuda para la interrelación entre personas, empresas y proyectos que se enmarcan dentro de los criterios zonales de planificación, el cambio en la matriz productiva del país y el Plan Nacional del Buen Vivir. En tal virtud, el estudio de una repotenciación mediante la aplicación de conocimientos y herramientas enmarcadas dentro de las comunicaciones VHF, es fundamental dentro del mejoramiento en términos de calidad de servicio dentro del área de concesión donde se fundamenta el estudio. El presente artículo realiza un análisis situacional de la red de radiocomunicaciones VHF actual de la Empresa Eléctrica Regional Centro Sur C. A., el área de concesión, localización y coberturas de los repetidores existentes, con el diagnóstico actual de la misma. Además, se desarrolla la propuesta de repotenciación detallando la infraestructura necesaria para su ejecución, la ampliación del área de cobertura, la configuración del software para la gestión e interconexión de los equipos de diferentes zonas.

  14. Towards EPR (European pressurized reactor)

    International Nuclear Information System (INIS)

    Anon.

    2003-01-01

    According to the French industry minister, it is nonsense continuing delaying the construction of an EPR prototype because France needs it in order to renew timely its park of nuclear reactors. The renewing is expected to begin in 2020 and will be assured with third generation reactors like EPR. A quick launching of the EPR prototype is necessary to have it being in service by 2012, the feedback operating experience that will be accumulated over the 8 years that will follow will be necessary to optimize the industrial version and to have it ready by 2020. The EPR reactor has indisputable assets: modern, safer, more competitive and it will produce less wastes than present nuclear reactors. The construction cost of an EPR prototype is estimated to 3 milliard Euros and the nuclear industry operators propose to finance it completely. The EPR prototype does not jeopardize the ambitious French program about renewable energy sources, France is committed to produce 21% of its electricity from renewable energies by 2010 and 10 milliard Euros will be invested over this period on wind energy. Nuclear energy and alternative energies must be considered as 2 aspects of a diversified energy policy. (A.C.)

  15. Assessment of an alanine EPR dosimetry technique with enhanced precision and accuracy

    CERN Document Server

    Hayes, R B; Wieser, A; Romanyukha, A A; Hardy, B L; Barrus, J K

    2000-01-01

    Dose reconstruction in the course of a series of blind tests demonstrated that an accuracy of 10 mGy for low doses and 1% for high doses can be achieved using EPR spectroscopy. This was accomplished using a combination of methodologies including polynomial filtration of the EPR spectrum, dosimeter rotation during scanning, use of an EPR standard fixed into the resonator and subtraction of all nonradiogenic signals. Doses were reconstructed over the range of 0.01-1000 Gy using this compound spectral EPR analysis. This EPR technique, being equally applicable to fractionated doses (such as those delivered during multiple radiotherapy treatments), was verified to exhibit dose reciprocity. Irradiated alanine dosimeters which were stored exhibited compound spectral EPR signal fading of ca 3% over 9 months. All error estimates given in this paper are given at the 1 standard deviation level and unless otherwise specified do not account for uncertainties in source calibration.

  16. Assessment of an alanine EPR dosimetry technique with enhanced precision and accuracy

    International Nuclear Information System (INIS)

    Hayes, Robert B.; Haskell, E.H.; Wieser, Albrecht; Romanyukha, Alexander A.; Hardy, Byron L.; Barrus, Jeffrey K.

    2000-01-01

    Dose reconstruction in the course of a series of blind tests demonstrated that an accuracy of 10 mGy for low doses and 1% for high doses can be achieved using EPR spectroscopy. This was accomplished using a combination of methodologies including polynomial filtration of the EPR spectrum, dosimeter rotation during scanning, use of an EPR standard fixed into the resonator and subtraction of all nonradiogenic signals. Doses were reconstructed over the range of 0.01-1000 Gy using this compound spectral EPR analysis. This EPR technique, being equally applicable to fractionated doses (such as those delivered during multiple radiotherapy treatments), was verified to exhibit dose reciprocity. Irradiated alanine dosimeters which were stored exhibited compound spectral EPR signal fading of ca 3% over 9 months. All error estimates given in this paper are given at the 1 standard deviation level and unless otherwise specified do not account for uncertainties in source calibration

  17. A VHF Class E DC-DC Converter with Self-Oscillating Gate Driver

    DEFF Research Database (Denmark)

    Andersen, Toke Meyer; Christensen, Søren K.; Knott, Arnold

    2011-01-01

    , is inherently resonant, and switching losses are greatly reduced by ensuring Zero Voltage Switching (ZVS) of the power semiconductor devices. A design method to ensure ZVS operation when combining the inverter, rectifier, and gate driver is provided. Several parasitic effects and their influence on converter......This paper describes the analysis and design of a DC-DC converter topology which is operational at frequencies in the Very High Frequency (VHF) band ranging from 30 MHz − 300 MHz. The presented topology, which consists of a class E inverter, class E rectifier, and self-oscillating gate driver...... operation are discussed, and measurement results of a 100 MHz prototype converter are presented and evaluated. The designed prototype converter verifies the described topology....

  18. Self-testing through EPR-steering

    International Nuclear Information System (INIS)

    Šupić, Ivan; Hoban, Matty J

    2016-01-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system. (paper)

  19. EPR by Areva. EPR the 1600+ MWe reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This brochure presents the GEN III+ EPR reactor designed by the Areva and Siemens consortium. The EPR reactor is a direct descendent of the well-proven N4 and KONVOI reactors, the most modern reactors in France and Germany. The EPR was designed by teams from KWU/Siemens and Framatome, EDF in France and the major German utilities, working in collaboration with both French and German safety authorities. The EPR integrates the results of decades of R and D programs, in particular those performed by the CEA (French Atomic Energy Commission) and the Karlsruhe Research Center in Germany. The EPR benefits from the experience of several thousand reactor-years of operation of pressurized water reactor technology. This experience has put 87 AREVA PWRs online throughout the world. Innovative Features: - An outer shell covering the reactor building, the spent fuel building and two of the four safeguard buildings provides protection against large commercial or military aircraft crash. - A heavy neutron reflector that surrounds the reactor core lowers uranium consumption. - An axial economizer inside the steam generator allows a high level of steam pressure and therefore high plant efficiency. - A core catcher allows passive collection and retention of the molten core should the reactor vessel fail in the highly unlikely event of a core melt. - A digital technology and a fully computerized control room with an operator friendly man-machine interface improve the reactor protection system.

  20. EPR by Areva. EPR the 1600+ MWe reactor

    International Nuclear Information System (INIS)

    2008-01-01

    This brochure presents the GEN III+ EPR reactor designed by the Areva and Siemens consortium. The EPR reactor is a direct descendent of the well-proven N4 and KONVOI reactors, the most modern reactors in France and Germany. The EPR was designed by teams from KWU/Siemens and Framatome, EDF in France and the major German utilities, working in collaboration with both French and German safety authorities. The EPR integrates the results of decades of R and D programs, in particular those performed by the CEA (French Atomic Energy Commission) and the Karlsruhe Research Center in Germany. The EPR benefits from the experience of several thousand reactor-years of operation of pressurized water reactor technology. This experience has put 87 AREVA PWRs online throughout the world. Innovative Features: - An outer shell covering the reactor building, the spent fuel building and two of the four safeguard buildings provides protection against large commercial or military aircraft crash. - A heavy neutron reflector that surrounds the reactor core lowers uranium consumption. - An axial economizer inside the steam generator allows a high level of steam pressure and therefore high plant efficiency. - A core catcher allows passive collection and retention of the molten core should the reactor vessel fail in the highly unlikely event of a core melt. - A digital technology and a fully computerized control room with an operator friendly man-machine interface improve the reactor protection system

  1. Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter.

    Science.gov (United States)

    Bourbin, Mathilde; Du, Yann Le; Binet, Laurent; Gourier, Didier

    2013-07-17

    Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the g factor; however, such parameters turn out not to suffice to fully determine a single EPR line. In this paper, we give the definition and practical implementation of a new EPR parameter based on the signal shape that we call the R10 factor. This parameter was originally defined in the case of a single symmetric EPR line and used as a new datation method for organic matter in the field of exobiology. Combined to classical EPR parameters, the proposed shape parameter provides a full description of an EPR spectrum and opens the way to novel applications like datation. Such a parameter is a powerful tool for future EPR studies, not only of carbonaceous matter, but also of any substance which spectrum exhibits a single symmetric line. The paper is a literate program-written using Noweb within the Org-mode as provided by the Emacs editor- and it also describes the full data analysis pipeline that computes the R10 on a real EPR spectrum.

  2. The EPR layout design

    International Nuclear Information System (INIS)

    Mast, U.; Le Carrer, P.Y.

    2001-01-01

    General: The European Pressurised Water Reactor (EPR) is a French - German development for the next generation of Pressurised Water Reactor. The new reactor design is based on the experiences of operation and design of nuclear power plants in both countries. The EPR fulfils enhanced safety standards, higher availability and a longer service life. Utilities aspects: For the Utilities one important requirement is the reduction of personnel exposure during maintenance and in-service inspection. The other significant requirement is of economic nature. The main points influencing costs, which have also impact on the layout, are: outage times, accessibility of the reactor building and the available maintenance and set down areas. The Utilities have also required to load the spent fuel assemblies into the shipping cask from the bottom of the fuel pool, because of the exclusion of the drop of the cask and in order to avoid contamination at the outer cask shell. Layout and safety aspects: All safety relevant Nuclear Island (NI) buildings are designed against design earthquake as well as explosion pressure wave. The protection against Airplane Crash (APC) is realised by civil and layout dispositions. The Reactor Building, the Safeguard Buildings division 2 and 3 and the Fuel Building are protected by concrete structures. The other safety relevant nuclear buildings are protected by geographical separation. Important safety requirements are the further reduction of the probability of severe accidents and the mitigation of such an accident on the plant area. For that, a spreading area for molten corium, a channel from the reactor pit to the spreading area and the In Containment Refuelling Water Storage Tank (IRWST) for flooding and initial cooling of the corium, were implemented in the design of the Reactor Building. Layout results: The following buildings are arranged on a common raft to protect them against design earthquake: Reactor Building (RB), Safeguard Buildings (SAB

  3. Analysis of EPR and FISH studies of radiation doses in persons who lived in the upper reaches of the Techa River.

    Science.gov (United States)

    Degteva, M O; Shagina, N B; Shishkina, E A; Vozilova, A V; Volchkova, A Y; Vorobiova, M I; Wieser, A; Fattibene, P; Della Monaca, S; Ainsbury, E; Moquet, J; Anspaugh, L R; Napier, B A

    2015-11-01

    Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated (89,90)Sr, the EPR and FISH assays were supported by measurements of (90)Sr-body burdens and estimates of (90)Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from (137)Cs incorporated in donors' soft tissues. It is shown here that the TRDS-based absorbed

  4. Analysis of EPR and FISH studies of radiation doses in persons who lived in the upper reaches of the Techa River

    Energy Technology Data Exchange (ETDEWEB)

    Degteva, M.O.; Shagina, N.B.; Shishkina, E.A.; Vozilova, A.V.; Volchkova, A.Y.; Vorobiova, M.I. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Wieser, A. [Helmholtz Centrum Munich, Neuherberg (Germany); Fattibene, P.; Della Monaca, S. [Instituto Superiore di Sanita, Rome (Italy); Ainsbury, E.; Moquet, J. [Public Health England, Chilton, Didcot (United Kingdom); Anspaugh, L.R. [University of Utah, Salt Lake City, UT (United States); Napier, B.A. [Pacific Northwest National Laboratory, Richland, WA (United States)

    2015-11-15

    Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated {sup 89,90}Sr, the EPR and FISH assays were supported by measurements of {sup 90}Sr-body burdens and estimates of {sup 90}Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from {sup 137}Cs incorporated in donors' soft tissues. It is shown here that the

  5. Analysis of EPR and FISH studies of radiation doses in persons who lived in the upper reaches of the Techa River

    International Nuclear Information System (INIS)

    Degteva, M.O.; Shagina, N.B.; Shishkina, E.A.; Vozilova, A.V.; Volchkova, A.Y.; Vorobiova, M.I.; Wieser, A.; Fattibene, P.; Della Monaca, S.; Ainsbury, E.; Moquet, J.; Anspaugh, L.R.; Napier, B.A.

    2015-01-01

    Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated "8"9","9"0Sr, the EPR and FISH assays were supported by measurements of "9"0Sr-body burdens and estimates of "9"0Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from "1"3"7Cs incorporated in donors' soft tissues. It is shown here that the TRDS

  6. The EPR in a few words: all you need to know about the EPR nuclear reactor

    International Nuclear Information System (INIS)

    2009-01-01

    After a brief presentation of the EPR (European - or Evolutionary - Pressurized Reactor) type nuclear reactor, this paper, proposed by the collective group 'Stop EPR', develops the following points: EPR is as dangerous as other reactors; EPR flouts democracy; France's energy demand do not need the construction of EPRs; the construction of EPRs is not a factor of economical and social development; EPR should not be constructed neither in France nor elsewhere and the present building sites should be cancelled; the EPR will not help France to increase its energy independence and protect itself from oil price increases; choosing the EPR is incompatible with the large investments to be made in energy conservation and renewable energies; the EPR is not a solution to climate change; the VHV line corridor that will starts at Flamanville is not justified and poses risks to the environment and public health

  7. Rapid-scan EPR imaging.

    Science.gov (United States)

    Eaton, Sandra S; Shi, Yilin; Woodcock, Lukas; Buchanan, Laura A; McPeak, Joseph; Quine, Richard W; Rinard, George A; Epel, Boris; Halpern, Howard J; Eaton, Gareth R

    2017-07-01

    In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250MHz. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. EPR: Some History and Clarification

    Science.gov (United States)

    Fine, Arthur

    2002-04-01

    Locality, separation and entanglement 1930s style. We’ll explore the background to the 1935 paper by Einstein, Podolsky and Rosen, how it was composed, the actual argument of the paper, the principles used, and how the paper was received by Schroedinger, and others.We’ll also look at Bohr’s response: the extent to which Bohr connects with what Einstein was after in EPR and the extent to EPR marks a shift in Bohr’s thinking about the quantum theory.

  9. Some ideas on the EPR

    International Nuclear Information System (INIS)

    2003-01-01

    Facing the debate and controversial between partisans and opponents of the European Pressurized Reactor construction, the SFP energy Group aims to offer some reflexions. In this framework the following topics are discussed: the french nuclear park and its replacement, the energy costs, the nuclear reactors profitability, the generation IV reactors. The paper examines then the EPR technology and its cost to conclude on the advantage of an EPR construction, in the case of an energy policy based on the nuclear. This last point seems to be the real challenge of the problem. (A.L.B.)

  10. EPR in B physics and elsewhere

    International Nuclear Information System (INIS)

    Lipkin, H.J.; Tel Aviv Univ.; Argonne National Lab., IL

    1997-01-01

    The application of Einstein-Podolsky-Rosen correlations in Υ(4s) → B anti B decays to research in CP violation is the first and probably only use of EPR as a technique for research in new physics. Elsewhere highly sophisticated EPR projects question EPR and test its predictions to look for violations of quantum mechanics, hidden variables, Bell''s inequalities, etc

  11. Risk reduction category (RRC-A) accident studies in the safety analysis report of the EPR trademark reactor

    International Nuclear Information System (INIS)

    Poehlmann, M.; Bleher, G.; Ismaier, A.; Knoll, A.; Levi, P.; Garcia, E. Vera; Schels, A.; Seitz, H.; Lima Campos, L.

    2013-01-01

    The Risk Reduction Category (RRC-A) is considered in the safety demonstration of nuclear reactors in addition to design basis operating conditions (Plant Condition Category, PCC), in order to analyze with a risk reduction approach any operating conditions with multiple failures. As extending the operating conditions of the plant 'beyond design basis', the Risk Reduction Category (RRC-A) is also denoted as Design Extension Condition (DEC-A). In the German licensing framework, the RRCA (or DEC-A) transients correspond to safety assessment level '4b' of the 'Sicherheitsanforderungen an Kernkraftwerke' (Safety Requirements for Nuclear Power Plants), Az. RS I 5 - 13303/01 of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. These RRC-A (or DEC-A) operating conditions require specific design provisions (implemented by manual or automatic action), known as RRC-A measures, intended to render consequences of accumulated failures admissible. In contrast, RRC-B constitute severe accidents that lead to core melt. Identification of RRC-A operating conditions and corresponding RRC-A measures is based on the use of results of probabilistic safety assessments. After the Fukushima accident the RRC-A accidents like Station Black Out (SBO) or Loss of Ultimate Heat Sink (LUHS) are of particular interest in the safety assessment of nuclear new builds. In several chapters of the Safety Analysis Report it is demonstrated that the AREVA EPRTM design is resistant at RRC-A accident conditions. (orig.)

  12. EPR: the nuclear impasse; EPR: l'impasse nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Marillier, F [Association Ecologiste Greenpeace (France)

    2008-07-01

    The questions relative to the climatic change constitute crucial challenges for the next ten years. In this context the author aims to show how the EPR project illustrates the nuclear french ''autism''. He presents and analyzes the international and environmental impacts of this obsolete technology, as a project useless and dangerous. (A.L.B.)

  13. EPR: the nuclear impasse; EPR: l'impasse nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Marillier, F. [Association Ecologiste Greenpeace (France)

    2008-07-01

    The questions relative to the climatic change constitute crucial challenges for the next ten years. In this context the author aims to show how the EPR project illustrates the nuclear french ''autism''. He presents and analyzes the international and environmental impacts of this obsolete technology, as a project useless and dangerous. (A.L.B.)

  14. Analysis of spin-Hamiltonian and molecular orbital coefficients of Cu2+ doped C8H11KO8 single crystal through EPR technique

    Science.gov (United States)

    Juliet sheela, K.; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

    2018-04-01

    Electron paramagnetic resonance (EPR) studies have been investigated at X-band microwave frequency on Cu2+ ion incorporated into the single crystal of potassium succinate-succinic acid (KSSA) at room temperature. The angular variation of the EPR spectra has shown two magnetically in-equivalent Cu2+ sites in the KSSA single crystal system. The spin Hamiltonian parameters g and A are determined which reveals that the site I and site II occupied in rhombic and axial local field symmetry around the impurity ion. Among the two paramagnetic impurity ions, sites one occupies at substituitional position in the place of monovalent cation (K+) in the crystal whereas the other enters in its lattice interstitially by the correlation of EPR and crystal structure data. From the calculated principle values gxx, gyy, gzz and Axx, Ayy, Azz of both the sites, the admixture coefficients and molecular orbital coefficients were evaluated which gives the information of ground state wave function and types of bonding of impurity ions with the ligands.

  15. EPR correlations and EPW distributions

    International Nuclear Information System (INIS)

    Bell, J.S.

    1995-01-01

    In the case of two free spin-zero particles, the wave function originally considered by Einstein, Podolsky and Rosen to exemplify EPR correlations has a non-negative Wigner distribution. This distribution gives an explicitly local account of the correlations. For an irreducible non-locality, more elaborate wave functions are required, with Wigner distributions which are not non-negative. (author)

  16. EPR measurements in irradiated polyacetylene

    International Nuclear Information System (INIS)

    Hola, O.; Foeldesova, M.

    1990-01-01

    The influence of γ-irradiation on the paramagnetic properties of polyacetylene, and the dependence of the EPR spectra on the radiation dose in samples of irradiated polyacetylene were studied. The measurements show that no essential changes of the spin mobility occurred during irradiation. (author) 3 refs.; 2 figs

  17. EPR study of human hair

    Czech Academy of Sciences Publication Activity Database

    Křížová, Jana; Káfuňková, Eva; Stopka, Pavel

    2005-01-01

    Roč. 99, č. 14 (2005), s. 217-218 ISSN 0009-2770 R&D Projects: GA MZd(CZ) NL7567; GA MZd(CZ) NB7377 Institutional research plan: CEZ:AV0Z40320502 Keywords : EPR Subject RIV: CA - Inorganic Chemistry Impact factor: 0.445, year: 2005

  18. Retrospective dosimetry using EPR and TL techniques: a status report

    International Nuclear Information System (INIS)

    Haskell, E.H.

    1996-01-01

    Methods of retrospective dosimetry, including luminescence and electron paramagnetic resonance spectroscopy (EPR), rely on measurement of accident dose absorbed by naturally occurring materials - ceramics in the case of both thermoluminescence (TL) and optically stimulated luminescence (OSL) and organic materials and bio- minerals in the case of EPR. Each of these methods relies on measurement of radiation defects resulting from accidental exposure. Since defects also result from natural sources of radiation over the lifetime of a sample, analysis is usually restricted to materials for which the natural dose may be determined and subtracted from the measured cumulative dose. Luminescence dating techniques rely heavily on an accurate assessment of cumulative dose from natural radiation sources, and dating research has provided us with the bulk of our knowledge in this area. Virtually all of the work on natural dose determination can be directly applied to retrospective techniques. With EPR techniques the cumulative dose from diagnostic x- rays is also of importance

  19. EPR structure of the gamma irradiated alanine spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Cabral P, A; Jimenez D, H; Urena N, F; Galindo, S; Bosch, P

    1992-03-15

    In this study is shown that the broadened five-line EPR pattern of the gamma irradiated alanine possibly decomposes into a more complex pattern when the recorded spectrum is subject to an operation of deconvolution. The EPR powder spectra of gamma irradiated DL- and L-alanine with and without binders are analysed. In all recorded spectra, each observed line is resolved into an asymmetrical triplet when a Gaussian distribution of 8.2 gauss width is removed, by deconvolution, from the observed spectrum. On the other hand, from a simple fitting analysis carried out on the original data, one encounters that some calculated relations between characteristic parameters, such as intensity ratios, deviate consistently from assumed height ratios. Both, from deconvolution and fitting results, a different structure is suggested for the observed broadened five-line EPR pattern of {gamma}-irradiated powder DL- and L-alanine. (Author)

  20. Retrospective dosimetry using EPR and TL techniques: a status report

    Energy Technology Data Exchange (ETDEWEB)

    Haskell, E.H.

    1996-12-31

    Methods of retrospective dosimetry, including luminescence and electron paramagnetic resonance spectroscopy (EPR), rely on measurement of accident dose absorbed by naturally occurring materials - ceramics in the case of both thermoluminescence (TL) and optically stimulated luminescence (OSL) and organic materials and bio- minerals in the case of EPR. Each of these methods relies on measurement of radiation defects resulting from accidental exposure. Since defects also result from natural sources of radiation over the lifetime of a sample, analysis is usually restricted to materials for which the natural dose may be determined and subtracted from the measured cumulative dose. Luminescence dating techniques rely heavily on an accurate assessment of cumulative dose from natural radiation sources, and dating research has provided us with the bulk of our knowledge in this area. Virtually all of the work on natural dose determination can be directly applied to retrospective techniques. With EPR techniques the cumulative dose from diagnostic x- rays is also of importance.

  1. EPR structure of the gamma irradiated alanine spectrum

    International Nuclear Information System (INIS)

    Cabral P, A.; Jimenez D, H.; Urena N, F.; Galindo, S.; Bosch, P.

    1992-03-01

    In this study is shown that the broadened five-line EPR pattern of the gamma irradiated alanine possibly decomposes into a more complex pattern when the recorded spectrum is subject to an operation of deconvolution. The EPR powder spectra of gamma irradiated DL- and L-alanine with and without binders are analysed. In all recorded spectra, each observed line is resolved into an asymmetrical triplet when a Gaussian distribution of 8.2 gauss width is removed, by deconvolution, from the observed spectrum. On the other hand, from a simple fitting analysis carried out on the original data, one encounters that some calculated relations between characteristic parameters, such as intensity ratios, deviate consistently from assumed height ratios. Both, from deconvolution and fitting results, a different structure is suggested for the observed broadened five-line EPR pattern of γ-irradiated powder DL- and L-alanine. (Author)

  2. Use of EPR to Solve Biochemical Problems

    Science.gov (United States)

    Sahu, Indra D.; McCarrick, Robert M.; Lorigan, Gary A.

    2013-01-01

    EPR spectroscopy is a very powerful biophysical tool that can provide valuable structural and dynamic information on a wide variety of biological systems. The intent of this review is to provide a general overview for biochemists and biological researchers on the most commonly used EPR methods and how these techniques can be used to answer important biological questions. The topics discussed could easily fill one or more textbooks; thus, we present a brief background on several important biological EPR techniques and an overview of several interesting studies that have successfully used EPR to solve pertinent biological problems. The review consists of the following sections: an introduction to EPR techniques, spin labeling methods, and studies of naturally occurring organic radicals and EPR active transition metal systems which are presented as a series of case studies in which EPR spectroscopy has been used to greatly further our understanding of several important biological systems. PMID:23961941

  3. EPR and X-ray diffraction investigation of some Greek marbles and limestones

    International Nuclear Information System (INIS)

    Duliu, Octavian; Grecu, Maria Nicoleta; Cristea, Corina

    2009-01-01

    Twelve different marble and limestone samples collected from well-known Greek quarries have been investigated by X-ray diffraction and electron paramagnetic resonance (EPR). X-ray diffraction spectra permitted to determine both major (calcite and dolomite) and minor (quartz or magnesite) mineralogical components. EPR has been used to investigate the same samples unirradiated and after 10 kGy gamma-ray irradiation. The unirradiated samples display typical EPR spectra of Mn 2+ in calcite and dolomite as well as a superposition of these while some samples displayed EPR free radicals signals of centers (low field signal) and centers (high field signal). From X-ray diffraction and EPR spectra it was possible to extract numerical values of several numerical parameters such as dolomite to calcite ratio, EPR intensity parameter, and low field to high field EPR signals intensity ratio. These values as well as the correlation coefficients between the digital functions that described the low field Mn 2+ ions EPR line have been used as entry data for cluster analysis to quantify the resemblance and differences between analyzed samples. (authors)

  4. EPR-technical codes - a common basis for the EPR

    International Nuclear Information System (INIS)

    Zaiss, W.; Appell, B.

    1997-01-01

    The design and construction of Nuclear Power Plants implies a full set of codes and standards to define the construction rules of components and equipment. Rules are existing and are currently implemented, respectively in France and Germany (mainly RCCs and KTA safety standards). In the frame of the EPR-project, the common objective requires an essential industrial work programme between engineers from both countries to elaborate a common set of codes and regulations. These new industrial rules are called the ETCs (EPR Technical Codes). In the hierarchy the ETCs are - in case of France - on the common level of basic safety rules (RFS), design and construction rules (RCC) and - in Germany - belonging to RSK guidelines and KTA safety standards. A set of six ETCs will be elaborated to cover: safety and process, mechanical components, electrical equipment, instrumentation and control, civil works, fire protection. (orig.)

  5. The Flamanville 3 EPR reactor; Le reacteur EPR Flamanville 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    On April 10. 2007, the french government authorized EDF to create on the site of Flamanville ( La Manche) a nuclear base installation containing a pressurized water EPR type reactor. This nuclear reactor, conceived by AREVA NP and EDF, is the first copy of a generation susceptible to replace later, at least partly, the French nuclear reactors at present in operation.Within the framework of its mission of technical support of the Authority of Nuclear Safety ( A.S.N.), the I.R.S.N. widely contributed successively: to define the general objectives of safety assigned to this new generation of pressurized water nuclear reactors; to analyze the options of safety proposed by EDF for the EPR project; To deepen, upstream to the authorization of creation, the evaluation of the step of safety and the measures of conception retained by EDF that have to allow to respect the objectives of safety which were notified to it. (N.C.)

  6. Observations of lightning processes using VHF radio interferometry

    Science.gov (United States)

    Rhodes, C. T.; Shao, X. M.; Krehbiel, P. R.; Thomas, R.

    1991-01-01

    A single station, multiple baseline radio interferometer was used to locate the direction of VHF radiation from lightning discharges with microsec time resolution. Radiation source directions and electric field waveforms were analyzed for various types of breakdown events. These include initial breakdown and K type events of in-cloud activity, and the leaders of initial and subsequent strokes to ground and activity during and following return strokes. Radiation during the initial breakdown of a flash and in the early stages of initial leaders to ground is found to be similar. In both instances, the activity consists of localized bursts of radiation that are intense and slow moving. Motion within a given burst is unresolved by the interferometer. Radiation from in-cloud K type events is essentially the same as that from dart leaders; in both cases it is produced at the leading edge of a fast moving streamer that propagates along a well defined, often extensive path. K type events are sometimes terminated by fast field changes that are similar to the return stroke initiated by dart leaders; such K type events are the in-cloud analog of the dart leader return stroke process.

  7. Electron paramagnetic resonance (EPR spectral components of spin-labeled lipids in saturated phospholipid bilayers: effect of cholesterol

    Directory of Open Access Journals (Sweden)

    Heverton Silva Camargos

    2013-01-01

    Full Text Available Electron paramagnetic resonance (EPR spectroscopy was used to study the main structural accommodations of spin labels in bilayers of saturated phosphatidylcholines with acyl chain lengths ranging from 16 to 22 carbon atoms. EPR spectra allowed the identification of two distinct spectral components in thermodynamic equilibrium at temperatures below and above the main phase transition. An accurate analysis of EPR spectra, using two fitting programs, enabled determination of the thermodynamic profile for these major probe accommodations. Focusing the analysis on two-component EPR spectra of a spin-labeled lipid, the influence of 40 mol % cholesterol in DPPC was studied.

  8. A fast method for ionized food identification: EPR

    International Nuclear Information System (INIS)

    Raffi, J.; Rubel, G.

    1990-01-01

    Electronic paramagnetic resonance allows the detection of ionized food only after dry storage, avoiding reaction of radicals with water. Dry and solid parts are used for analysis (bones for meat and fish, kernels for fruits). Dosimetry is possible by EPR spectrometry of alanine-L fixed on products treated in industrial irradiators [fr

  9. EPR compared to international requirements (Mainly EUR)

    International Nuclear Information System (INIS)

    Broecker, B.

    1996-01-01

    A number of European Utilities have entered an agreement to write common requirements dedicated to future light water nuclear power plants to be built in Europe. The activities are known under the sign EUR (European Utilities Requirements). EPR, the future European Pressurized water Reactor, is the first installation of this type which will be operational from the year 2000 onwards, must fulfill the European requirements. EPR will serve as a test whether these requirements are realistic and well balanced. At the basic design stage of EPR, this paper concentrates on four main topics: the requirements which are new compared with existing reactors and which put a major challenge to the designer; the requirements today still open and the way they can be met by the EPR or not; the points for which already today the EPR special requirements exceed the EUR; the examples where the design of the EPR has given feedback which has led to a change of the EUR. EPR and EUR are different approaches to the reactor of the future. EUR is a set of requirements which leaves a flexibility to the designer while EPR is a real project which defines the technical solutions. EPR will fulfill the EUR and will at the same time serve as a test whether these requirements are realistic. EPR will also fulfill international requirements with minor changes. (J.S.). 7 figs

  10. Hydrogen Analyses in the EPR

    International Nuclear Information System (INIS)

    Worapittayaporn, S.; Eyink, J.; Movahed, M.

    2008-01-01

    In severe accidents with core melting large amounts of hydrogen may be released into the containment. The EPR provides a combustible gas control system to prevent hydrogen combustion modes with the potential to challenge the containment integrity due to excessive pressure and temperature loads. This paper outlines the approach for the verification of the effectiveness and efficiency of this system. Specifically, the justification is a multi-step approach. It involves the deployment of integral codes, lumped parameter containment codes and CFD codes and the use of the sigma criterion, which provides the link to the broad experimental data base for flame acceleration (FA) and deflagration to detonation transition (DDT). The procedure is illustrated with an example. The performed analyses show that hydrogen combustion at any time does not lead to pressure or temperature loads that threaten the containment integrity of the EPR. (authors)

  11. EPR dosimetry of irradiated human teeth

    International Nuclear Information System (INIS)

    Rodas Duran, J.E.; Panzeri, H.; Mascarenhas, S.

    1985-01-01

    The determination of the absorbed radiation dose in man may be made by Electron Paramagnetic Resonance (EPR) spectroscopy of dental enamel. We analysed the EPR signals for dental enamel submitted to gamma radiation in doses between 1 Gy and 25 Gy. We conclude that independent of the type of tooth analysed there exists a linear relation between the EPR signals and the absorbed doses. These studies were extended to enamel irradiated with gamma rays and with X rays in doses between 0.1 Gy and 0.6 Gy. The graph of the intensity of the EPR signals as a function of the dose has a slope of 0.22. This calibration may be used to calculate the absorbed dose for humans from a measurement of the EPR signal from small samples of enamel taken from any permanent tooth. Finally we comment on some EPR studies of effects of radiation of milk teeth. (author)

  12. EPR studies of melanin from Cladosporium cladosporioides

    International Nuclear Information System (INIS)

    Pilawa, B.; Buszman, E.; Latocha, M.; Wilczok, T.

    1996-01-01

    Free radical properties of Cladosporium cladosporioides mycelium and melanin, and synthetic eumelanin and pheomelanin were studied by electron paramagnetic resonance method. Single EPR line and complex EPR spectrum with hyperfine splitting were measured for model DOPA-melanin and cysteinyldopa-melanin, respectively. EPR spectra of Cladosporium cladosporioides samples and pheomelanin show the same character. The concentration of paramagnetic centers in melanins isolated from Cladosporium cladosporioides is considerably higher than that of crude mycelium, whereas the EPR line widths are lower for mycelium than for melanin samples. For all analyzed samples the increase of EPR signals intensity with the increase of microwave power, and the decrease of intensities after saturation were observed the low values of microwave power sufficient for EPR lines saturation demonstrate that the spin-lattice relaxation times of unpaired electrons in melanins are long. (author)

  13. Pharmaceutical applications of in vivo EPR

    International Nuclear Information System (INIS)

    Maeder, K.

    1998-01-01

    The aim of this article is to discuss the applications of in vivo EPR in the field of pharmacy. In addition to direct detection of free radical metabolites and measurement of oxygen, EPR can be used to characterize the mechanisms of drug release from biodegradable polymers. Unique information about drug concentration, the microenvironment (viscosity, polarity, pH) and biodistribution (by localized measurement or EPR Imaging) can be obtained. (author)

  14. Letter to the Editor: Complete maps of the aspect sensitivity of VHF atmospheric radar echoes

    Directory of Open Access Journals (Sweden)

    R. M. Worthington

    1999-08-01

    Full Text Available Using the MU radar at Shigaraki, Japan (34.85°N, 136.10°E, we measure the power distribution pattern of VHF radar echoes from the mid-troposphere. The large number of radar beam-pointing directions (320 allows the mapping of echo power from 0° to 40° from zenith, and also the dependence on azimuth, which has not been achieved before at VHF wavelengths. The results show how vertical shear of the horizontal wind is associated with a definite skewing of the VHF echo power distribution, for beam angles as far as 30° or more from zenith, so that aspect sensitivity cannot be assumed negligible at any beam-pointing angle that most existing VHF radars are able to use. Consequently, the use of VHF echo power to calculate intensity of atmospheric turbulence, which assumes only isotropic backscatter at large beam zenith angles, will sometimes not be valid.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence; instruments and techniques

  15. Electron paramagnetic resonance (EPR) in medical dosimetry

    International Nuclear Information System (INIS)

    Schauer, David A.; Iwasaki, Akinori; Romanyukha, Alexander A.; Swartz, Harold M.; Onori, Sandro

    2006-01-01

    This paper describes the fundamentals of electron paramagnetic resonance (EPR) and its application to retrospective measurements of clinically significant doses of ionizing radiation. X-band is the most widely used in EPR dosimetry because it represents a good compromise between sensitivity, sample size and water content in the sample. Higher frequency bands (e.g., W and Q) provide higher sensitivity, but they are also greatly influenced by water content. L and S bands can be used for EPR measurements in samples with high water content but they are less sensitive than X-band. Quality control for therapeutic radiation facilities using X-band EPR spectrometry of alanine is also presented

  16. Analysis of local symmetry and impurity location of Cu2+ ions doped C8H11KO8 single crystal through EPR technique for site I

    Science.gov (United States)

    Sheela, K. Juliet; Subbulakshmi, N.; Subramanian, P.

    2018-04-01

    Electron paramagnetic resonance (EPR) studies have been investigated on Cu2+ ion incorporated into the single crystals of potassium succinate-succinic acid (KSSA) at room temperature. Two magnetically in-equivalent Cu2+ sites in the lattice are identified, among them site I has been reported. The spin Hamiltonian parameters are determined with the fitting of spectra to rhombic symmetry crystalline field. The co-ordination of the Cu2+ ion in this molecule is a distorted dodecahedron. From the calculated gxx, gyy, gzz and Axx, Ayy, Azz and their directional cosines values, location of site I impurity ion Cu2+ could be identified as a substituitional one. Also the ground state wave function of the impurity ion was found to be d2z.

  17. Ion upflow and downflow at the topside ionosphere observed by the EISCAT VHF radar

    Directory of Open Access Journals (Sweden)

    M. Endo

    2000-02-01

    Full Text Available We have determined the MLT distribution and KP dependence of the ion upflow and downflow of the thermal bulk oxygen ion population based on a data analysis using the EISCAT VHF radar CP-7 data obtained at Tromsø during the period between 1990 and 1996: (1 both ion upflow and downflow events can be observed at any local time (MLT, irrespective of dayside and nightside, and under any magnetic disturbance level, irrespective of quiet and disturbed levels; (2 these upflow and downflow events are more frequently observed in the nightside than in the dayside; (3 the upflow events are more frequently observed than the downflow events at any local time except midnight and at any KP level and the difference of the occurrence frequencies between the upflow and downflow events is smaller around midnight; and (4 the occurrence frequencies of both the ion upflow and downflow events appear to increase with increasing KP level, while the occurrence frequency of the downflow appears to stop increasing at some KP level.Key words: Ionosphere (particle acceleration; plasma waves and instabilities - Space plasma physics (transport processes

  18. Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

    International Nuclear Information System (INIS)

    Van Erk, W; Luijks, G M J F; Hitchcock, W

    2011-01-01

    Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W -1 drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

  19. Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

    Energy Technology Data Exchange (ETDEWEB)

    Van Erk, W [Philips Lighting, Sondervick 47, 5505 NB Veldhoven (Netherlands); Luijks, G M J F [Advanced Development Lighting, Philips Lighting, PO Box 80020, 5600 JM Eindhoven (Netherlands); Hitchcock, W, E-mail: Gerard.luijks@philips.com [Philips Lighting Company, 7265 Route 54, Bath, NY 14810 (United States)

    2011-06-08

    Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W{sup -1} drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

  20. Pulse EPR distance measurements to study multimers and multimerisation

    Science.gov (United States)

    Ackermann, Katrin; Bode, Bela E.

    2018-06-01

    Pulse dipolar electron paramagnetic resonance (PD-EPR) has become a powerful tool for structural biology determining distances on the nanometre scale. Recent advances in hardware, methodology, and data analysis have widened the scope to complex biological systems. PD-EPR can be applied to systems containing lowly populated conformers or displaying large intrinsic flexibility, making them all but intractable for cryo-electron microscopy and crystallography. Membrane protein applications are of particular interest due to the intrinsic difficulties for obtaining high-resolution structures of all relevant conformations. Many drug targets involved in critical cell functions are multimeric channels or transporters. Here, common approaches for introducing spin labels for PD-EPR cause the presence of more than two electron spins per multimeric complex. This requires careful experimental design to overcome detrimental multi-spin effects and to secure sufficient distance resolution in presence of multiple distances. In addition to obtaining mere distances, PD-EPR can also provide information on multimerisation degrees allowing to study binding equilibria and to determine dissociation constants.

  1. Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. EPR of exchange coupled systems

    CERN Document Server

    Bencini, Alessandro

    2012-01-01

    From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon

  3. EPR investigations on technetium compounds

    International Nuclear Information System (INIS)

    Abram, U.; Munze, R.; Kirmse, R.; Stach, J.

    1986-01-01

    Stimulated by the widespread use of the isotope /sup 99m/Tc in the field of nuclear medicine, there has been a substantial growth of interest in the chemistry of this man-made element. A particular need emerges for analytical methods allowing solution investigations of coordination compounds of technetium with low substance use. Considering these facts, Electron Paramagnetic Resonance Spectroscopy (EPR) appears to be a very suitable method because only very small amounts of the compounds are needed (lower than 1 mg). The resulting spectra give information regarding the valence state, symmetry and bonding properties of the compounds under study

  4. EPR spectroscopic investigation of psoriatic finger nails.

    Science.gov (United States)

    Nakagawa, Kouichi; Minakawa, Satoko; Sawamura, Daisuke

    2013-11-01

    Nail lesions are common features of psoriasis and found in almost half of the patients. However, there is no feasible spectroscopic method evaluating changes and severity of nail psoriasis. EPR (electron paramagnetic resonance) might be feasible for evaluating nail conditions in the patients of psoriasis. Finger nails of five cases with nail psoriasis, (three females and two males) were examined. Nail samples were subjected to the EPR assay. The small piece of the finger nail (1.5 × 5 mm(2)) was incubated in ~50 μM 5-DSA (5-doxylstearic acid) aqueous solutions for about 60 min at 37°C. After rinsing and wiping off the excess 5-DSA solution, the nail samples were measured by EPR. EPR spectra were analyzed using the intensity ratio (Fast/Slow) of the two motions at the peaks of the lower magnetic field. We observed two distinguishable sites on the basis of the EPR results. In addition, the modern EPR calculation was performed to analyze the spectra obtained. The nail psoriasis-related region is 2~3 times higher than that of the control. The present EPR results show that there are two distinguishable sites in the nail. In the case of nail psoriasis, the fragile components are 2~3 times more than those of the control. Thus, the EPR method is thought to be a novel and reliable method of evaluating the nail psoriasis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. EPR dosimetry with tooth enamel: A review

    International Nuclear Information System (INIS)

    Fattibene, Paola; Callens, Freddy

    2010-01-01

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

  6. CW EPR parameters reveal cytochrome P450 ligand binding modes.

    Science.gov (United States)

    Lockart, Molly M; Rodriguez, Carlo A; Atkins, William M; Bowman, Michael K

    2018-06-01

    Cytochrome P450 (CYP) monoxygenses utilize heme cofactors to catalyze oxidation reactions. They play a critical role in metabolism of many classes of drugs, are an attractive target for drug development, and mediate several prominent drug interactions. Many substrates and inhibitors alter the spin state of the ferric heme by displacing the heme's axial water ligand in the resting enzyme to yield a five-coordinate iron complex, or they replace the axial water to yield a nitrogen-ligated six-coordinate iron complex, which are traditionally assigned by UV-vis spectroscopy. However, crystal structures and recent pulsed electron paramagnetic resonance (EPR) studies find a few cases where molecules hydrogen bond to the axial water. The water-bridged drug-H 2 O-heme has UV-vis spectra similar to nitrogen-ligated, six-coordinate complexes, but are closer to "reverse type I" complexes described in older liteature. Here, pulsed and continuous wave (CW) EPR demonstrate that water-bridged complexes are remarkably common among a range of nitrogenous drugs or drug fragments that bind to CYP3A4 or CYP2C9. Principal component analysis reveals a distinct clustering of CW EPR spectral parameters for water-bridged complexes. CW EPR reveals heterogeneous mixtures of ligated states, including multiple directly-coordinated complexes and water-bridged complexes. These results suggest that water-bridged complexes are under-represented in CYP structural databases and can have energies similar to other ligation modes. The data indicates that water-bridged binding modes can be identified and distinguished from directly-coordinated binding by CW EPR. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  8. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification in with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  9. EPR dosimetry - present and future

    International Nuclear Information System (INIS)

    Regulla, D.F.

    1999-01-01

    In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as co-ordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as biomarkers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (ASTM), and the International Organisation of Standards (ISO) as well as those of the International Commission on Radiation Units and Measurements (ICRU) considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (author)

  10. EPR Dosimetry - Present and Future

    Energy Technology Data Exchange (ETDEWEB)

    Regulla, D.F. [GSF - National Research Centre for Environment and Health, Institute of Radiation Protection, 85764 Neuherberg (Germany)

    1999-07-01

    In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as in coordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as bio markers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (Astm), and by the International Organisation of Standards (ISO). The International Commission on Radiation Units and Measurements (ICRU) is considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (Author)

  11. EPR Dosimetry - Present and Future

    International Nuclear Information System (INIS)

    Regulla, D.F.

    1999-01-01

    In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as in coordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as bio markers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (Astm), and by the International Organisation of Standards (ISO). The International Commission on Radiation Units and Measurements (ICRU) is considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (Author)

  12. Analysis of the consequences of the anomaly in the Flamanville EPR reactor pressure vessel head domes on their serviceability. Report to the Advisory Committee of Experts for Nuclear Pressure Equipment. Public version. Session of 26 and 27 June 2017

    International Nuclear Information System (INIS)

    CATTEAU, R.; HERVIOU, K.

    2017-06-01

    Appendix 7. ASN decided to convene the GP ESPN on 26 and 27 June 2017 to obtain its technical opinion on the consequences of the anomaly on the serviceability of the Flamanville EPR reactor pressure vessel head domes. This report recalls the approach adopted by Areva NP to demonstrate that the material of the Flamanville EPR reactor pressure vessel head domes is ductile and tough enough for the operating conditions of this equipment and evaluates whether or not the anomaly compromises their serviceability. It deals in turn with the demonstration approach adopted by Areva NP, the fast fracture risk assessment (manufacturing inspections, material characterisation, characterisation of thermomechanical loadings and mechanical analysis), the impact of the irregularities detected in the Areva NP Creusot Forge plant and the in-service monitoring provisions. This report was drawn up jointly by IRSN and the Nuclear Pressure Equipment Department (DEP) of ASN

  13. EPR imaging of dose distributions aiming at applications in radiation therapy

    International Nuclear Information System (INIS)

    Lund, E.; Kolbun, N.; Adolfsson, E.; Gustafsson, H.

    2014-01-01

    A one-dimensional electron paramagnetic resonance (EPR) imaging method for visualisation of dose distributions in photon fields has been developed. Pressed pellets of potassium dithionate were homogeneously irradiated in a 60 Co radiation field to 600 Gy. The EPR analysis was performed with an X-Band (9.6 GHz) Bruker E540 EPR and EPR imaging spectrometer equipped with an E540 GC2X two-axis X-band gradient coil set with gradients along the y axis (along the sample tube) and z axis (along B 0 ) and an ER 4108TMHS resonator. Image reconstruction, including deconvolution, baseline corrections and corrections for the resonator sensitivity, was performed using an in-house-developed Matlab code for the purpose to have a transparent and complete algorithm for image reconstruction. With this method, it is possible to visualise a dose distribution with an accuracy of ∼5 % within ±5 mm from the centre of the resonator. (authors)

  14. Testing VHF/GPS collar design and safety in the study of free-roaming horses.

    Directory of Open Access Journals (Sweden)

    Gail H Collins

    Full Text Available Effective and safe monitoring techniques are needed by U.S. land managers to understand free-roaming horse behavior and habitat use and to aid in making informed management decisions. Global positioning system (GPS and very high frequency (VHF radio collars can be used to provide high spatial and temporal resolution information for detecting free-roaming horse movement. GPS and VHF collars are a common tool used in wildlife management, but have rarely been used for free-roaming horse research and monitoring in the United States. The purpose of this study was to evaluate the design, safety, and detachment device on GPS/VHF collars used to collect free-roaming horse location and movement data. Between 2009 and 2010, 28 domestic and feral horses were marked with commercial and custom designed VHF/GPS collars. Individual horses were evaluated for damage caused by the collar placement, and following initial observations, collar design was modified to reduce the potential for injury. After collar modifications, which included the addition of collar length adjustments to both sides of the collar allowing for better alignment of collar and neck shapes, adding foam padding to the custom collars to replicate the commercial collar foam padding, and repositioning the detachment device to reduce wear along the jowl, we observed little to no evidence of collar wear on horses. Neither custom-built nor commercial collars caused injury to study horses, however, most of the custom-built collars failed to collect data. During the evaluation of collar detachment devices, we had an 89% success rate of collar devices detaching correctly. This study showed that free-roaming horses can be safely marked with GPS and/or VHF collars with minimal risk of injury, and that these collars can be a useful tool for monitoring horses without creating a risk to horse health and wellness.

  15. Thermal induced EPR signals in tooth enamel

    International Nuclear Information System (INIS)

    Fattibene, P.; Aragno, D.; Onori, S.; Pressello, M.C.

    2000-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used to detect the effects of temperature on powdered human tooth enamel, not irradiated in the laboratory. Samples were heated at temperature between 350 and 450, at 600 and at 1000 deg. C, for different heating times, between 6 min and 39 h. Changes in the EPR spectra were detected, with the formation of new signals. Possible correlation between the changes in EPR spectra and modifications in the enamel and in the mineral phase of bone detected with other techniques is discussed. The implications for dosimetric applications of signals induced by overheating due to mechanical friction during sample preparation are underlined

  16. Nitrosyl hemoglobins: EPR above 80 K

    Energy Technology Data Exchange (ETDEWEB)

    Wajnberg, E.; Bemski, G.; El-Jaick, L.J.; Alves, O.C.

    1995-03-01

    The EPR spectra of nitrosyl hemoglobin and myoglobin in different conditions (native, denatured and lyophilized), as well as of hematin-NO were obtained in the temperature range of 80 K-280 K. There is a substantial and reversible.decrease of the areas of the EPR spectra of all the hemoglobin samples above 150 K. The interpretation of the results implies the existence of two conformational states in thermal equilibrium only one of which is EPR detectable. Thermodynamical parameters are determined for the hexa and penta-coordinated cases. (author). 25 refs, 3 figs.

  17. Nitrosyl hemoglobins: EPR above 80 K

    International Nuclear Information System (INIS)

    Wajnberg, E.; Bemski, G.; El-Jaick, L.J.; Alves, O.C.

    1995-03-01

    The EPR spectra of nitrosyl hemoglobin and myoglobin in different conditions (native, denatured and lyophilized), as well as of hematin-NO were obtained in the temperature range of 80 K-280 K. There is a substantial and reversible.decrease of the areas of the EPR spectra of all the hemoglobin samples above 150 K. The interpretation of the results implies the existence of two conformational states in thermal equilibrium only one of which is EPR detectable. Thermodynamical parameters are determined for the hexa and penta-coordinated cases. (author). 25 refs, 3 figs

  18. EPR ohmic heating energy storage

    International Nuclear Information System (INIS)

    Heck, F.M.; Stillwagon, R.E.; King, E.I.

    1977-01-01

    The Ohmic Heating (OH) Systems for all the Experimental Power Reactor (EPR) designs to date have all used temporary energy storage to assist in providing the OH current charge required to build up the plasma current. The energies involved (0.8 x 10 9 J to 1.9 x 10 9 J) are so large as to make capacitor storage impractical. Two alternative approaches are homopolar dc generators and ac generators. Either of these can be designed for pulse duty and can be made to function in a manner similar to a capacitor in the OH circuit and are therefore potential temporary energy storage devices for OH systems for large tokamaks. This study compared total OH system costs using homopolar and ac generators to determine their relative merits. The total system costs were not significantly different for either type of machine. The added flexibility and the lower maintenance of the ac machine system make it the more attractive approach

  19. SimLabel: a graphical user interface to simulate continuous wave EPR spectra from site-directed spin labeling experiments.

    Science.gov (United States)

    Etienne, E; Le Breton, N; Martinho, M; Mileo, E; Belle, V

    2017-08-01

    Site-directed spin labeling (SDSL) combined with continuous wave electron paramagnetic resonance (cw EPR) spectroscopy is a powerful technique to reveal, at the residue level, structural transitions in proteins. SDSL-EPR is based on the selective grafting of a paramagnetic label on the protein under study, followed by cw EPR analysis. To extract valuable quantitative information from SDSL-EPR spectra and thus give reliable interpretation on biological system dynamics, numerical simulations of the spectra are required. Such spectral simulations can be carried out by coding in MATLAB using functions from the EasySpin toolbox. For non-expert users of MATLAB, this could be a complex task or even impede the use of such simulation tool. We developed a graphical user interface called SimLabel dedicated to run cw EPR spectra simulations particularly coming from SDSL-EPR experiments. Simlabel provides an intuitive way to visualize, simulate, and fit such cw EPR spectra. An example of SDSL-EPR spectra simulation concerning the study of an intrinsically disordered region undergoing a local induced folding is described and discussed. We believe that this new tool will help the users to rapidly obtain reliable simulated spectra and hence facilitate the interpretation of their results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Natural alpha recoil particle radiation and ionizing radiation sensitivities in quartz detected with EPR: implications for geochronometry

    International Nuclear Information System (INIS)

    Rink, W.J.; Odom, A.L.

    1991-01-01

    The electron paramagnetic resonance EPR signals in granitic quartz samples of known age are studied. Time-integrated alpha recoil activity and EPR signal intensity are more significantly correlated than sample age and EPR signal intensity. Neutron activation analysis for internal uranium and thorium in quartz are reported. Natural germanium EPR signals are observed in pegmatitic quartz samples and one granitic quartz. Pegmatitic quartz exhibits germanium EPR center growth competing strongly with E' center growth, apparently leading to depleted natural concentrations of E' centers. Calculations of lattice vacancy accumulation associated with alpha recoil damage are presented and compared with concentrations of paramagnetic oxygen vacancies in the quartz. Based on the results reported, the potential and problems associated with dating quartz are discussed, relating both to accumulated lattice damage and the additive dose methods. (author)

  1. Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations.

    Science.gov (United States)

    Crăciun, Cora

    2014-08-01

    CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids' EPR behaviour, for different spin system symmetries. The metrics' efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Homogeneity and EPR metrics for assessment of regular grids used in CW EPR powder simulations

    Science.gov (United States)

    Crăciun, Cora

    2014-08-01

    CW EPR powder spectra may be approximated numerically using a spherical grid and a Voronoi tessellation-based cubature. For a given spin system, the quality of simulated EPR spectra depends on the grid type, size, and orientation in the molecular frame. In previous work, the grids used in CW EPR powder simulations have been compared mainly from geometric perspective. However, some grids with similar homogeneity degree generate different quality simulated spectra. This paper evaluates the grids from EPR perspective, by defining two metrics depending on the spin system characteristics and the grid Voronoi tessellation. The first metric determines if the grid points are EPR-centred in their Voronoi cells, based on the resonance magnetic field variations inside these cells. The second metric verifies if the adjacent Voronoi cells of the tessellation are EPR-overlapping, by computing the common range of their resonance magnetic field intervals. Beside a series of well known regular grids, the paper investigates a modified ZCW grid and a Fibonacci spherical code, which are new in the context of EPR simulations. For the investigated grids, the EPR metrics bring more information than the homogeneity quantities and are better related to the grids’ EPR behaviour, for different spin system symmetries. The metrics’ efficiency and limits are finally verified for grids generated from the initial ones, by using the original or magnetic field-constraint variants of the Spherical Centroidal Voronoi Tessellation method.

  3. EPR method for the detection of sensitization in stainless steels

    International Nuclear Information System (INIS)

    Clarke, W.L.; Cowan, R.L.

    1980-01-01

    The overall objective of the program was to improve the reliability of reactor system piping by increasing knowledge of failure causing mechanisms and by enhancing the capability for design evaluation and analysis. Toward the attainment of that objective, a technique has been developed to measure the degree of sensitization quantitatively in thermally treated AISI-304, -304L, -316 and 316L stainless steels. The Electrochemical Potentiokinetic Reactivation (EPR) test was developed because of an industrial need for a rapid, nondestructive, quantitative field test which could be used for assessing sensitization in reactor components. The EPR method consists of developing potentiokinetic curves on a polarized sample obtained by controlled potential sweep from the passive to the active region (reactivation) in a specific electrolyte; details of the test technique have been reported

  4. Using rapid scan EPR to improve the detection limit of quantitative EPR by more than one order of magnitude

    OpenAIRE

    Möser, J.; Lips, K.; Tseytlin, M.; Eaton, G.; Eaton, S.; Schnegg, A

    2017-01-01

    X band rapid scan EPR was implemented on a commercially available Bruker ELEXSYS E580 spectrometer. Room temperature rapid scan and continuous wave EPR spectra were recorded for amorphous silicon powder samples. By comparing the resulting signal intensities the feasibility of performing quantitative rapid scan EPR is demonstrated. For different hydrogenated amorphous silicon samples, rapid scan EPR results in signal to noise improvements by factors between 10 and 50. Rapid scan EPR is thus ca...

  5. New loophole for the EPR paradox

    OpenAIRE

    Feldmann, Michel

    1999-01-01

    We exhibit a classical model free from any paradox which exactly simulates the spin EPR test. We conclude that Bell's inequality violation is a strictly classical phenomenon, contrary to a general belief.

  6. Spin entanglement, decoherence and Bohm's EPR paradox

    OpenAIRE

    Cavalcanti, E. G.; Drummond, P. D.; Bachor, H. A.; Reid, M. D.

    2007-01-01

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with cu...

  7. Perspectives of shaped pulses for EPR spectroscopy

    Science.gov (United States)

    Spindler, Philipp E.; Schöps, Philipp; Kallies, Wolfgang; Glaser, Steffen J.; Prisner, Thomas F.

    2017-07-01

    This article describes current uses of shaped pulses, generated by an arbitrary waveform generator, in the field of EPR spectroscopy. We show applications of sech/tanh and WURST pulses to dipolar spectroscopy, including new pulse schemes and procedures, and discuss the more general concept of optimum-control-based pulses for applications in EPR spectroscopy. The article also describes a procedure to correct for experimental imperfections, mostly introduced by the microwave resonator, and discusses further potential applications and limitations of such pulses.

  8. Applications of EPR in radiation research

    CERN Document Server

    Lund, Anders

    2014-01-01

    Applications of EPR in Radiation Research is a multi-author contributed volume presented in eight themes: I. Elementary radiation processes (in situ and low temperature radiolysis, quantum solids); II: Solid state radiation chemistry (crystalline, amorphous and heterogeneous systems); III: Biochemistry, biophysics and biology applications (radicals in biomaterials, spin trapping, free-radical-induced DNA damage); IV: Materials science (polymeric and electronic materials, materials for treatment of nuclear waste, irradiated food); V: Radiation metrology (EPR-dosimetry, retrospective and medical

  9. EPR Spectroscopy in Environmental Lichen-Indication

    Science.gov (United States)

    Bondarenko, P. V.; Nguyet, Le Thi Bich; Zhuravleva, S. E.; Trukhan, E. M.

    2017-09-01

    The paramagnetic properties of lichens were investigated using EPR spectroscopy and Xanthoria parietina (L.) Th. Fr. as a case study. It was found that the concentration of paramagnetic centers in lichen thalli increased as the air-pollution level increased. Possible formation mechanisms of the paramagnetic centers in lichens were discussed. The efficiency of using EPR spectroscopy to study lichens as environmental quality indicators was demonstrated.

  10. EPR of alanine irradiated by neutrons

    International Nuclear Information System (INIS)

    Pivovarov, S.P.; Seredavina, T.A.; Zhdanov, S.V.; Mul'gin, S.I.; Zhakparov, R.K.

    2001-01-01

    In the work the first results of EPR studies of alanine, irradiated with diverse doses at neutron cyclotron generator different conditions and on the critical reactor stand are presented. A dose linearity dependence of EPR signal is observing, the methods of γ-background contribution separation are discussed. Obtain results is giving the basis to recommendation of alanine as an effective detector irradiation. However it is demanded the farther study on clarification of radiation sensitivity value dependence on the neutron energy spectrum form

  11. Study on the EPR/dosimetric properties of some substituted alanines

    International Nuclear Information System (INIS)

    Gancheva, Veselka; Sagstuen, Einar; Yordanov, Nicola D.

    2006-01-01

    Polycrystalline phenyl-alanine and perdeuterated l-α-alanine (l-α-alanine-d 4 ) were studied as potential high-energy radiation-sensitive materials (RSM) for solid state/EPR dosimetry. It was found that phenyl-alanine exhibits a linear dose response in the dose region 0.1-17kGy. However, phenyl-alanine is about 10 times less sensitive to γ-irradiation than standard l-α-alanine irradiated at the same doses. Moreover, the EPR response from phenyl-alanine is unstable and, independent of the absorbed dose, decreases by about 50% within 20 days after irradiation upon storage at room temperature. γ-irradiated polycrystalline perdeuterated l-α-alanine (CD 3 CD(NH 2 )COOH) has not previously been studied at room temperature by EPR spectroscopy. The first part of the present analysis was with respect to the structure of the EPR spectrum. By spectrum simulations, the presence of at least two radiation induced free radicals, R 1 =CH 3 C*(H)COOH and R 2 =H 3 N + -C*(CH 3 )COO - , was confirmed very clearly. Both these radicals were suggested previously from EPR and ENDOR studies of standard alanine crystals. The further investigations into the potential use of alanine-d 4 as RSM, after choosing optimal EPR spectrometer settings parameters for this purpose, show that it is ca. two times more sensitive than standard l-α-alanine

  12. Analysis of the procedure proposed by AREVA to prove adequate toughness of the domes of the Flamanville 3 EPR reactor pressure vessel (RPV) lower head and closure head. Session of 30 September 2015. Public version

    International Nuclear Information System (INIS)

    Catteau, R.; Cadet-Mercier, S.

    2015-01-01

    undergone an in-plant hydraulic test. It was installed at the beginning of 2014 in the reactor pit situated in the reactor building and was welded to the primary branches. The vessel head produced from the upper dome underwent repairs after ultrasonic inspections revealed indications in the welds of the control rod drive mechanism (CRDM) penetrations. These repairs had been examined by the Advisory Committee of Experts for Nuclear Pressure Equipment during the session of 14 September 2011. Ultrasonic inspections of the new welds have been carried out since then and the work is nearing completion. The vessel head is still in the manufacturer's shops and must undergo a hydraulic test before being shipped to the site. This report gives a recap of the regulatory framework and the history of application of the technical qualification requirement, then presents and analyses the procedure adopted by AREVA to prove the adequate toughness of the material of the domes of the Flamanville 3 EPR RPV. It adopts a position more specifically on the new test campaign proposed by AREVA to evaluate the mechanical properties of the segregation zone. The Rapporteur underlines however that the proof of adequate toughness has been defined in the AREVA file on the basis of a list of operating situations that could not be analysed for inclusion in this report given the late date of transmission of the elements and the time available. The results of the new tests that are going to be performed, the exhaustive and encompassing nature of the chosen operating situations and the impact of the mechanical properties of the segregation zone on the analysis of the mechanical behaviour of the vessel in incident, accident and test situations shall be analysed in a later phase. This report has been drawn up jointly by IRSN and the Nuclear Pressure Equipment Department (DEP) of ASN

  13. IC modelling in the IRSN EPR level 1 PSA

    International Nuclear Information System (INIS)

    Delache, J.

    2012-01-01

    Today in France, an EPR (European Pressurized Water Reactor) Unit is under construction at the Flamanville site. The creation authorization was granted in April 2007 and the plant commissioning is planned for 2012. The plant operator (EDF) provided for the construction license several PSA (Probabilistic Safety Assessment) studies. IRSN, as TSO (Technical Safety Organisation), wishes to dispose of the appropriate knowledge and tools for the independent verification of the operator studies and so developed its own model of PSA level 1. The goal is not to rebuild the plant operator PSA (with a full scope...) but to dispose of a simplified model able to clearly point out specific important issues. In the IRSN model a particular effort has recently been done on the Digital IC modelling. The IC (Instrumentation and Control) is modelled in the IRSN EPR PSA by using Fault Trees. Instead, EDF EPR PSA applies the COMPACT model to simplify the command and instrumentation logics. The IRSN model is more detailed in order to be more accurate in the global analysis of the Digital IC. For instance the communication ways between automates are considered as well as the failure of support systems. The model is still under development mainly in order to define the CCF (Common Cause Failure) which may be considered. (authors)

  14. TL, EPR and optical absorption in natural grossular crystal

    Energy Technology Data Exchange (ETDEWEB)

    Yauri, J.M. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil); Department of Physics, University of San Agustin, Av. Independencia S/N, Arequipa (Peru); Cano, N.F. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil)], E-mail: nilocano@dfn.if.usp.br; Watanabe, S. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo (Brazil)

    2008-10-15

    Grossular is one of six members of silicate Garnet group. Two samples GI and GII have been investigated concerning their luminescence thermally stimulated (TL). EPR and optical absorption and the measurements were carried out to find out whether or not same point defects are responsible for all three properties. Although X-rays diffraction analysis has shown that both GI and GII have practically the same crystal structure of a standard grossular crystal, they presented different behavior in many aspects. The TL glow curve shape, TL response to radiation dose, the effect of annealing at high temperatures before irradiation, the dependence of UV bleaching parameters on peak temperature, all of them differ going from GI to GII. The EPR signals around g=2.0 as well as at g=4.3 and 6.0 have much larger intensity in GI than in GII. Very high temperature (>800 deg. C) annealing causes large increase in the bulk background absorption in GI, however, only very little in GII. In the cases of EPR and optical absorption, the difference in their behavior can be attributed to Fe{sup 3+} ions; however, in the TL case one cannot and the cause was not found as yet.

  15. TL, EPR and optical absorption in natural grossular crystal

    International Nuclear Information System (INIS)

    Yauri, J.M.; Cano, N.F.; Watanabe, S.

    2008-01-01

    Grossular is one of six members of silicate Garnet group. Two samples GI and GII have been investigated concerning their luminescence thermally stimulated (TL). EPR and optical absorption and the measurements were carried out to find out whether or not same point defects are responsible for all three properties. Although X-rays diffraction analysis has shown that both GI and GII have practically the same crystal structure of a standard grossular crystal, they presented different behavior in many aspects. The TL glow curve shape, TL response to radiation dose, the effect of annealing at high temperatures before irradiation, the dependence of UV bleaching parameters on peak temperature, all of them differ going from GI to GII. The EPR signals around g=2.0 as well as at g=4.3 and 6.0 have much larger intensity in GI than in GII. Very high temperature (>800 deg. C) annealing causes large increase in the bulk background absorption in GI, however, only very little in GII. In the cases of EPR and optical absorption, the difference in their behavior can be attributed to Fe 3+ ions; however, in the TL case one cannot and the cause was not found as yet

  16. Broadband VHF observations for lightning impulses from a small satellite SOHLA-1 (Maido 1)

    Science.gov (United States)

    Morimoto, T.; Kikuchi, H.; Ushio, T.; Kawasaki, Z.; Hidekazu, H.; Aoki, T.

    2009-12-01

    Lightning Research Group of Osaka University (LRG-OU) has been developing VHF Broadband Digital Interferometer (DITF) to image precise lightning channels and monitor lightning activity widely. The feature of broadband DITF is its ultrawide bandwidth (from 25MHz to 100MHz) and implicit redundancy for estimating VHF source location. LRG-OU considers an application of the broadband DITF to the spaceborne measurement system and joins the SOHLA (Space Oriented Higashi-Osaka Leading Associate) satellite project. The SOHLA satellite project represents a technology transfer program to expand the range of the space development community in Japan. The objective is to get SMEs (Small and Medium sized manufacturing Enterprises) involved in small space projects and new space technologies. Under the cooperative agreement, JAXA (Japan Aerospace Exploration Agency) intends to contribute to socio-economic development by returning its R&D results to society, and SOHLA tries to revitalize the local economy through the commercialization of versatile small satellites. According to the agreement, JAXA provides SOHLA its technical information on small satellites and other technical assistance for the development of the small satellites, SOHLA-1. The prime objective of the SOHLA-1 program is to realize low-cost and short term development of a microsatellite which utilizes the components and bus technologies of JAXA’s MicroLabSat. SOHLA-1 is a spin-stabilized microsatellite of MicroLabSat heritage (about 50 kg). The spin axis is fixed to inertial reference frame. The spin axis (z-axis) lies in the plane containing the solar direction and the normal to the orbital plane. LRG-OU takes responsibility for a science mission of SOHLA-1. To examine the feasibility of the DITF receiving VHF lightning impulses in space, LRG-OU proposes the BMW (Broadband Measurement of Waveform for VHF Lightning Impulses). BMW consists of a single pair of an antenna, a band-pass filter, an amplifier, and an

  17. Taguchi analysis of extrusion variables and composition effects on the morphology and mechanical properties of EPR-g-MA toughened polyamide 6 and its composite with short glass fiber

    International Nuclear Information System (INIS)

    Shojaei, A.; Fereydoon, M.

    2009-01-01

    Various compositions of maleated ethylene-propylene-rubber (EPR-g-MA) toughened polyamide 6 without and with short glass fiber, i.e. 5-20 wt.% rubber and 5-20 wt.% fiber, are prepared using an industrial twin-screw extruder at different levels of feed rate (100-250 kg/h), screw speed (200-450 rpm) and barrel temperature (230-260 deg. C). Trial runs designed based on the Taguchi's orthogonal arrays are subjected to tensile, impact, scanning electron microscopy (SEM) and optical microscopy tests; and the results are used to perform the analysis of variance (ANOVA). It is shown that the rubber particle size decreases significantly by increasing the rubber content for the unreinforced blend. The results also indicate that the composition of the compounds is the most influential factor on the phase morphology and mechanical properties of both the unreinforced and reinforced blends compared to the extrusion variables. But the processing parameters can also influence the performance characteristics slightly. The most important processing parameter, among the others, is shown to be the mixing temperature, which decreases the fiber length greatly and leads to the thermo-mechanical degradation of the polymers above 240 deg. C

  18. Some radiation safety aspects of operating medical generators of VHF electromagnetic energy

    International Nuclear Information System (INIS)

    Bosevski, V.; Radev, S.; Donev, Ch.

    1977-01-01

    The state of radiation safety in physiotherapy practice using very-high-frequency diathermy was studied with regard to personnel and patient protection. A specially devised shielding set to protect patients and personnel is offered for adoption, and the necessity is insistently stressed of prohibiting any patient head or gonad exposure. It is pointed out that the protective set developed may also be used at facilities employing other types of VHF electromagnetic energy sources. (author)

  19. Adjuvant VHF therapy in locally recurrent and primary unresectable rectal cancer

    International Nuclear Information System (INIS)

    Trotter, J.M.; Lamb, M.H.; Bayliss, E.J.; Edis, A.J.; Blackwell, J.B.; Shepherd, J.M.; Cassidy, B.

    1996-01-01

    In a prospective randomized study, 434 MHz microwave therapy combined with external beam radiotherapy (VHF+RT) was compared with standard external beam radiotherapy (RT) in controlling locally recurrent or unresectable primary adenocarcinoma of the rectum. Independent assessors documented quality of life scores, performance status, toxicities local response to treatment, and systemic disease progression before treatment and after treatment and every 8 week thereafter. Of 75 patients randomized, 73 were eligible for inclusion in the study. Forty-three of these patients had local pelvic tumour recurrence only and 21 also had distant metastases. In addition, nine patients had primary inoperable carcinomas, two of whom also had metastases. Thirty-seven patients were randomized to RT and 36 to VHF+RT. Th median dose of radiation in the VHF+RT arm was 4275 cGy with a median fraction size of 150 cGy and median duration of therapy of 48.5 days versus 4500 cGy in the RT-only arm with a median fraction size of 180 cGy and median duration of therapy of 38 days. These doses are unlikely to be significantly different in biological effect. No significant difference between the two groups was observed in extent and duration of local control, measures of toxicity or quality of life scores. Additionally, survival and cumulative incidence of pelvic site of first progression did not differ significantly between the groups. It is concluded that VHF microwave therapy in conjunction with radiotherapy produces no therapeutic advantage over conventional radiation therapy alone in the treatment of locally recurrent rectal carcinoma. 35 refs., 8 tabs., 3 figs

  20. TH-AB-209-09: Quantitative Imaging of Electrical Conductivity by VHF-Induced Thermoacoustics

    Energy Technology Data Exchange (ETDEWEB)

    Patch, S; Hull, D [Avero Diagnostics, Irving, TX (United States); See, W [Medical College of Wisconsin, Milwaukee, WI (United States); Hanson, G [UW-Milwaukee, Milwaukee, WI (United States)

    2016-06-15

    Purpose: To demonstrate that very high frequency (VHF) induced thermoacoustics has the potential to provide quantitative images of electrical conductivity in Siemens/meter, much as shear wave elastography provides tissue stiffness in kPa. Quantitatively imaging a large organ requires exciting thermoacoustic pulses throughout the volume and broadband detection of those pulses because tomographic image reconstruction preserves frequency content. Applying the half-wavelength limit to a 200-micron inclusion inside a 7.5 cm diameter organ requires measurement sensitivity to frequencies ranging from 4 MHz down to 10 kHz, respectively. VHF irradiation provides superior depth penetration over near infrared used in photoacoustics. Additionally, VHF signal production is proportional to electrical conductivity, and prostate cancer is known to suppress electrical conductivity of prostatic fluid. Methods: A dual-transducer system utilizing a P4-1 array connected to a Verasonics V1 system augmented by a lower frequency focused single element transducer was developed. Simultaneous acquisition of VHF-induced thermoacoustic pulses by both transducers enabled comparison of transducer performance. Data from the clinical array generated a stack of 96-images with separation of 0.3 mm, whereas the single element transducer imaged only in a single plane. In-plane resolution and quantitative accuracy were measured at isocenter. Results: The array provided volumetric imaging capability with superior resolution whereas the single element transducer provided superior quantitative accuracy. Combining axial images from both transducers preserved resolution of the P4-1 array and improved image contrast. Neither transducer was sensitive to frequencies below 50 kHz, resulting in a DC offset and low-frequency shading over fields of view exceeding 15 mm. Fresh human prostates were imaged ex vivo and volumetric reconstructions reveal structures rarely seen in diagnostic images. Conclusion

  1. Characterization of VHF radar observations associated with equatorial Spread F by narrow-band optical measurements

    Directory of Open Access Journals (Sweden)

    R. Sekar

    2004-09-01

    Full Text Available The VHF radars have been extensively used to investigate the structures and dynamics of equatorial Spread F (ESF irregularities. However, unambiguous identification of the nature of the structures in terms of plasma depletion or enhancement requires another technique, as the return echo measured by VHF radar is proportional to the square of the electron density fluctuations. In order to address this issue, co-ordinated radar backscatter and thermospheric airglow intensity measurements were carried out during March 2003 from the MST radar site at Gadanki. Temporal variations of 630.0-nm and 777.4-nm emission intensities reveal small-scale ("micro" and large-scale ("macro" variations during the period of observation. The micro variations are absent on non-ESF nights while the macro variations are present on both ESF and non-ESF nights. In addition to the well-known anti-correlation between the base height of the F-region and the nocturnal variation of thermospheric airglow intensities, the variation of the base height of the F-layer, on occasion, is found to manifest as a bottomside wave-like structure, as seen by VHF radar on an ESF night. The micro variations in the airglow intensities are associated with large-scale irregular plasma structures and found to be in correspondence with the "plume" structures obtained by VHF radar. In addition to the commonly observed depletions with upward movement, the observation unequivocally reveals the presence of plasma enhancements which move downwards. The observation of enhancement in 777.4-nm airglow intensity, which is characterized as plasma enhancement, provides an experimental verification of the earlier prediction based on numerical modeling studies.

  2. Comparison Study of Lightning observations from VHF interferometer and Geostationary Lightning Mapper

    Science.gov (United States)

    Kudo, A.; Stock, M.; Ushio, T.

    2017-12-01

    We compared the optical observation from Geostationary Lightning Mapper (GLM) which is mounted on the geostationary meteorological satellite GOES-16 launched last year, and the radio observations from the ground-based VHF broad band interferometer. GLM detects 777.4 nm wavelength infrared optical signals from thunderstorm cells which are illuminated by the heated path during lightning discharge, and was developed mainly for the purpose of increasing the lead time for warning of severe weather and clarifying the discharge mechanism. Its detection has 2 ms frame rate, and 8 km square of space resolution at nadir. The VHF broad band interferometer is able to capture the electromagnetic waves from 20 MHz to 75 MHz and estimate the direction of arrival of the radiation sources using the interferometry technique. This system also has capability of observing the fast discharge process which cannot be captured by other systems, so it is expected to able to make detailed comparison. The recording duration of the system is 1 second. We installed the VHF broad band interferometer which consists of three VHF antenna and one fast antenna at Huntsville, Alabama from April 22nd to May 15th and in this total observation period, 720 triggers of data were observed by the interferometer. For comparison, we adopted the data from April 27th , April 30th. Most April 27th data has GLM "event" detection which is coincident time period. In time-elevation plot comparison, we found GLM detection timing was well coincide with interferometer during K-changes or return strokes and few detection during breakdown process. On the other hand, no GLM detection near the site for all data in April 30th and we are triyng to figure out the reason. We would like to thank University of Alabama Huntsville, New Mexico Institute of Mining and Technology, and RAIRAN Pte. Ltd for the help during the campaign.

  3. Low VHF Channel Measurements and Simulations in Indoor and Outdoor Scenarios

    Science.gov (United States)

    2015-05-01

    Transactions on. 2002;50(5):591-599. 22. Nerguizian C, Despins C, Affes S, Djadel M. Radio-channel characterization of an underground mine at 2.4 ghz...INTENTIONALLY LEFT BLANK. viii 1. Introduction Reliable wireless communication is of paramount importance for many important civilian and military...report, we study near-ground, wireless channel modeling in the lower VHF band for indoor and indoor/outdoor scenarios, drawing from extensive propagation

  4. Bias-Voltage Stabilizer for HVHF Amplifiers in VHF Pulse-Echo Measurement Systems.

    Science.gov (United States)

    Choi, Hojong; Park, Chulwoo; Kim, Jungsuk; Jung, Hayong

    2017-10-23

    The impact of high-voltage-high-frequency (HVHF) amplifiers on echo-signal quality is greater with very-high-frequency (VHF, ≥100 MHz) ultrasound transducers than with low-frequency (LF, ≤15 MHz) ultrasound transducers. Hence, the bias voltage of an HVHF amplifier must be stabilized to ensure stable echo-signal amplitudes. We propose a bias-voltage stabilizer circuit to maintain stable DC voltages over a wide input range, thus reducing the harmonic-distortion components of the echo signals in VHF pulse-echo measurement systems. To confirm the feasibility of the bias-voltage stabilizer, we measured and compared the deviations in the gain of the HVHF amplifier with and without a bias-voltage stabilizer. Between -13 and 26 dBm, the measured gain deviations of a HVHF amplifier with a bias-voltage stabilizer are less than that of an amplifier without a bias-voltage stabilizer. In order to confirm the feasibility of the bias-voltage stabilizer, we compared the pulse-echo responses of the amplifiers, which are typically used for the evaluation of transducers or electronic components used in pulse-echo measurement systems. From the responses, we observed that the amplitudes of the echo signals of a VHF transducer triggered by the HVHF amplifier with a bias-voltage stabilizer were higher than those of the transducer triggered by the HVHF amplifier alone. The second, third, and fourth harmonic-distortion components of the HVHF amplifier with the bias-voltage stabilizer were also lower than those of the HVHF amplifier alone. Hence, the proposed scheme is a promising method for stabilizing the bias voltage of an HVHF amplifier, and improving the echo-signal quality of VHF transducers.

  5. A beaded collar for dual micro GPS/VHF transmitter attachment to nutria

    Science.gov (United States)

    Haramis, G.M.; White, T.S.

    2011-01-01

    We report on the development of an approximately 85-g beaded collar for dual micro GPS/VHF transmitter attachment to semi-aquatic nutria (Myocastor coypus). Prototype collars were tested on captive nutria and refined during field trials. Central to the design was novel use of the VHF transmitter antenna as a collar. A circular collar was formed by passing the 44-cm antenna cable through a pre-made hole in the transmitter, leaving an approximately 16-cm upright antenna. GPS units were mounted separately via a hole in the base of each unit. For good satellite contact, GPS units (28 g) were maintained at the nape of the neck by counterbalance of the heavier VHF transmitters (50 g) positioned under the neck. To reduce friction, we lined the collar with alternate-sized plastic and, later, more durable nylon beads. The final collar configuration was worn for approximately 1 month deployments with only minor neck abrasion; one collar was worn successfully for 5 months. Foot entanglement remained the greatest risk of injury from the collar. By fitting collars tightly, we reduced the incidence of foot entanglement to 2 of 33 deployments (6%). Successful GPS tracks were acquired on 29 of 33 deployments (88%).

  6. A signature correlation study of ground target VHF/UHF ISAR imagery

    Science.gov (United States)

    Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Kersey, William T.; Waldman, Jerry; Carter, Steve; Nixon, William E.

    2003-09-01

    VV and HH-polarized radar signatures of several ground targets were acquired in the VHF/UHF band (171-342 MHz) by using 1/35th scale models and an indoor radar range operating from 6 to 12 GHz. Data were processed into medianized radar cross sections as well as focused, ISAR imagery. Measurement validation was confirmed by comparing the radar cross section of a test object with a method of moments radar cross section prediction code. The signatures of several vehicles from three vehicle classes (tanks, trunks, and TELs) were measured and a signature cross-correlation study was performed. The VHF/UHF band is currently being exploited for its foliage penetration ability, however, the coarse image resolution which results from the relatively long radar wavelengths suggests a more challenging target recognition problem. One of the study's goals was to determine the amount of unique signature content in VHF/UHF ISAR imagery of military ground vehicles. Open-field signatures are compared with each other as well as with simplified shapes of similar size. Signatures were also acquired on one vehicle in a variety of configurations to determine the impact of monitor target variations on the signature content at these frequencies.

  7. Effect of geomagnetic storms on VHF scintillations observed at low latitude

    Science.gov (United States)

    Singh, S. B.; Patel, Kalpana; Singh, A. K.

    2018-06-01

    A geomagnetic storm affects the dynamics and composition of the ionosphere and also offers an excellent opportunity to study the plasma dynamics. In the present study, we have used the VHF scintillations data recorded at low latitude Indian station Varanasi (Geomag. latitude = 14^{°}55^' }N, long. = 154^{°}E) which is radiated at 250 MHz from geostationary satellite UFO-02 during the period 2011-2012 to investigate the effects of geomagnetic storms on VHF scintillation. Various geomagnetic and solar indices such as Dst index, Kp index, IMF Bz and solar wind velocity (Vx) are used to describe the geomagnetic field variation observed during geomagnetic storm periods. These indices are very helpful to find out the proper investigation and possible interrelation between geomagnetic storms and observed VHF scintillation. The pre-midnight scintillation is sometimes observed when the main phase of geomagnetic storm corresponds to the pre-midnight period. It is observed that for geomagnetic storms for which the recovery phase starts post-midnight, the probability of occurrence of irregularities is enhanced during this time and extends to early morning hours.

  8. EPR Dosimetry for ageing effect in NPP

    International Nuclear Information System (INIS)

    Choi, Hoon; Lim, Young Ki; Kim, Jong Seog; Jung, Sun Chul

    2005-01-01

    As one of the retrospective dosimetry method, EPR spectroscopy has been studied by many research up to theses days. As a dosimeter for EPR spectroscopy, Alanine is already a well known dosimeter in the field of radiation therapy and dose assessment in radiological accident by its characteristics as good linearity in a wide range of energy level and extremely low signal fading on time. Through technical document of IAEA, the EPR dosimetry method using alanine sample was published in 2000 after research by coordinated project on management of ageing of in-containment I and C cables. Although alanine sample is regarded as a good EPR dosimeter like above ageing assessment field, actually the assessment of radiation should be done at least for two fuel cycles, because of its relatively low irradiation environment in almost all spots in power plant. So, for getting more accurate detection value of radiation, another material is tested for being put in simultaneously inside the power plant with alanine. The test result for lithium formate monohydrate (HCO 2 LiH 2 0) was presented below for checking its possibility for being applied as EPR dosimeter for this project

  9. Magnetic, catalytic, EPR and electrochemical studies on binuclear ...

    Indian Academy of Sciences (India)

    Magnetic, catalytic, EPR and electrochemical studies on binuclear copper(II) complexes ... to the oxidation of 3,5-di--butylcatechol to the corresponding quinone. ... EPR spectral studies in methanol solvent show welldefined four hyperfine ...

  10. Investigation of radical locations in various sesame seeds by CW EPR and 9-GHz EPR imaging.

    Science.gov (United States)

    Nakagawa, K; Hara, H

    2015-01-01

    We investigated the location of radical in various sesame seeds using continuous-wave (CW) electron paramagnetic resonance (EPR) and 9-GHz EPR imaging. CW EPR detected persistent radicals (single line) for various sesame seeds. The EPR linewidth of black sesame seeds was narrower than that of the irradiated white sesame seeds. A very small signal was detected for the white sesame seeds. Two-dimensional (2D) imaging using a 9-GHz EPR imager showed that radical locations vary for various sesame seeds. The paramagnetic species in black sesame seeds were located on the seed coat (skin) and in the hilum region. The signal with the highest intensity was obtained from the hilum part. A very low-intensity image was observed for the white sesame seeds. In addition, the 2D imaging of the irradiated white sesame seeds showed that free radicals were located throughout the entire seed. For the first time, CW EPR and 9-GHz EPR imaging showed the exact location of radical species in various sesame seeds.

  11. Selfcalibrated alanine/EPR dosimeters. A new generation of solid state/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    Alanine/EPR dosimeters are well established as secondary, reference dosimeters for high-energy radiation. However, there are various sources of uncertainty in the evaluation of absorbed dose. This arises primarily from the necessity to calibrate each EPR spectrometer and each batch of dosimeters before their use. In order to overcome this disadvantage, a new generation alanine/EPR dosimeter has been developed, and its possibilities as a radiation detector are reported. Principally, it is a mixture of alanine, some quantity of EPR active substance, and a binding material. The EPR active substance, acting as an internal EPR standard, is chosen to have EPR parameters which are independent of the irradiation dose. The simultaneous recording of the spectra of both the sample and the standard under the same experimental conditions and the estimation of the ratio I alanine /I Mn as a function of the absorbed dose strongly reduces the uncertainties. The response of these dosimeters for 60 Co γ-radiation exhibits excellent linearity and reproducibility in the range of absorbed dose, 10 2 - 5 x 10 4 Gy. (author)

  12. Computational and instrumental methods in EPR

    CERN Document Server

    Bender, Christopher J

    2006-01-01

    Computational and Instrumental Methods in EPR Prof. Bender, Fordham University Prof. Lawrence J. Berliner, University of Denver Electron magnetic resonance has been greatly facilitated by the introduction of advances in instrumentation and better computational tools, such as the increasingly widespread use of the density matrix formalism. This volume is devoted to both instrumentation and computation aspects of EPR, while addressing applications such as spin relaxation time measurements, the measurement of hyperfine interaction parameters, and the recovery of Mn(II) spin Hamiltonian parameters via spectral simulation. Key features: Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T1) and Spin-Spin (T2) Relaxation Times Improvement in the Measurement of Spin-Lattice Relaxation Time in Electron Paramagnetic Resonance Quantitative Measurement of Magnetic Hyperfine Parameters and the Physical Organic Chemistry of Supramolecular Systems New Methods of Simulation of Mn(II) EPR Spectra: Single Cryst...

  13. EPR spectra of some irradiated polycrystalline perrhenate

    International Nuclear Information System (INIS)

    Zaitseva, N.G.; Constantinescu, M.; Georgescu, R.; Constantinescu, O.

    1978-10-01

    An EPR study of the paramagnetic centers formed by γ, electron and neutron irradiation of the NaReO 4 and KReO 4 was made. In the EPR spectra of the powder samples irradiated γ, with electrons and neutrons, the presence of three types of paramagnetic centers was observed. From the EPR parameters, the centers were attributed to the ReOsub(4)sup(.), ReOsub(3)sup(.) and ReOsub(2)sup(.) radicals respectively. The lower intensity of the spectra observed by KReO 4 samples irradiation showed a higher radioresistance of the KReO 4 than that of NaReO 4 . A radiolitical scheme taking into account the paramagnetic centers formation was proposed. (author)

  14. Relativistic Nonlocality and the EPR Paradox

    Science.gov (United States)

    Chamberlain, Thomas

    2014-03-01

    The exact violation of Bell's Inequalities is obtained with a local realistic model for spin. The model treats one particle that comprises a quantum ensemble and simulates the EPR data one coincidence at a time as a product state. Such a spin is represented by operators σx , iσy ,σz in its body frame rather than the usual set of σX ,σY ,σZ in the laboratory frame. This model, assumed valid in the absence of a measuring probe, contains both quantum polarizations and coherences. Each carries half the EPR correlation, but only half can be measured using coincidence techniques. The model further predicts the filter angles that maximize the spin correlation in EPR experiments.

  15. Pressurized water reactors: the EPR project

    International Nuclear Information System (INIS)

    Py, J.P.; Yvon, M.

    2007-01-01

    EPR (originally 'European pressurized water reactor', and now 'evolutionary power reactor') is a model of reactor initially jointly developed by French and German engineers which fulfills the particular safety specifications of both countries but also the European utility requirements jointly elaborated by the main European power companies under the initiative of Electricite de France (EdF). Today, two EPR-based reactors are under development: one is under construction in Finland and the other, Flamanville 3 (France), received its creation permit decree on April 10, 2007. This article presents, first, the main objectives of the EPR, and then, describes the Flamanville 3 reactor: reactor type and general conditions, core and conditions of operation, primary and secondary circuits with their components, main auxiliary and recovery systems, man-machine interface and instrumentation and control system, confinement and serious accidents, arrangement of buildings. (J.S.)

  16. Spin entanglement, decoherence and Bohm's EPR paradox.

    Science.gov (United States)

    Cavalcanti, E G; Drummond, P D; Bachor, H A; Reid, M D

    2009-10-12

    We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with current quantum optical technologies. For a macroscopic number of particles prepared in a correlated state, spin entanglement and the EPR paradox can be demonstrated using our criteria for efficiencies eta > 1/3 and eta > 2/3 respectively. This indicates a surprising insensitivity to loss decoherence, in a macroscopic system of ultra-cold atoms or photons.

  17. EPR of impurity ions in disordered solids

    International Nuclear Information System (INIS)

    Kliava, J.

    1986-01-01

    The state of the art in the EPR spectroscopy of disordered solids is reviewed and theoretical aspects of the EPR shape in disordered systems are discussed. Emphasis is placed on the concept of the joint probability density of the spin Hamiltonian parameters. A survey of experimental data is provided on distributions of spin Hamiltonian parametes obtained using computer simulation techniques. A quantitative information is given on the short-range ordering in disordered materials available from EPR studies. A procedure of extracting such type of data which consists in a transformation from the distribution of the spin Hamiltonian parameters to that of atomic coordinates in the surrounding of a paramagnetic center is outlined. Numerical estimates of the degree of continuous disorder are reviewed

  18. EPR study of free radicals in bread

    Science.gov (United States)

    Yordanov, Nicola D.; Mladenova, Ralitsa

    2004-05-01

    The features of the recorded EPR spectra of paramagnetic species formed in bread and rusk are reported. The appearance of free radicals in them is only connected with their thermal treatment since the starting materials (flour and grains) exhibit very weak EPR signal. The obtained EPR spectra are complex and indicate that: (i) the relative number of paramagnetic species depends on the temperature and treating time of the raw product; (ii) the g-values are strongly temperature dependent with a tendency to coincide at t≥220 °C. Because of the relatively low (150-220 °C) temperature of thermal treatment, the studied free radicals can be assumed to appear in the course of the browning (Maillard) reaction and not to the carbonization of the material.

  19. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Nanjing University of Posts and Telecommunications, School of Tongda, Nanjing (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Zhuge, L.J. [Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Soochow University, Analysis and Testing Center, Suzhou (China); Wu, X.M. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai (China)

    2015-01-23

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO{sub x} are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf{sup 2+} and Hf{sup 4+}. The HfErO films are composed with the structures of HfO{sub 2}, HfO and ErO{sub x}, which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO{sub 2} in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO{sub 2} are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  20. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang, H.Y.; He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C.; Zhuge, L.J.; Wu, X.M.

    2015-01-01

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO x are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf 2+ and Hf 4+ . The HfErO films are composed with the structures of HfO 2 , HfO and ErO x , which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO 2 in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO 2 are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  1. Harmonization of dosimetric information obtained by different EPR methods: Experience of the Techa river study

    Energy Technology Data Exchange (ETDEWEB)

    Volchkova, A. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Shishkina, E.A., E-mail: ElenaA.Shishkina@gmail.com [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Ivanov, D. [Institute of Metal Physics, Russian Academy of Sciences, 18, S. Kovalevskoy Str., 620041 Yekaterinburg (Russian Federation); Timofeev, Yu. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Fattibene, P.; Della Monaca, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare, Viale Regina Elena 299, 00161 Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, German Research Centre for Environmental Health, D-85764 Neuherberg (Germany); Degteva, M.O. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation)

    2011-09-15

    Between 1949 and 1956 the Techa River (Southern Urals, Russia) was contaminated as a result of releases of radioactive waste by the Mayak Production Association. EPR dosimetry with tooth enamel has been used to estimate the external exposure of Techa riverside residents over the last 17 years. The database 'Tooth' of the Urals Research Center for Radiation Medicine (URCRM) has accumulated about 1000 EPR measurements of tooth enamel from the rural population of the Urals region. The teeth were investigated by laboratories of Russia, USA, Germany and Italy. Most of the enamel samples were measured several times in different laboratories. Each laboratory used different equipment and its own methods for sample preparation and EPR spectra analysis. Even measurements performed at the same laboratory over 10-15 years may not be assumed as uniform: methods change with time, and equipment is subject to aging. These two factors influenced EPR performance. The purpose of this study is, therefore, the harmonization of EPR data accumulated during long-term dosimetric investigations in the Southern Urals for further pooled analysis. The results will be used for external dose evaluation in the Techa River region.

  2. Using rapid-scan EPR to improve the detection limit of quantitative EPR by more than one order of magnitude.

    Science.gov (United States)

    Möser, J; Lips, K; Tseytlin, M; Eaton, G R; Eaton, S S; Schnegg, A

    2017-08-01

    X-band rapid-scan EPR was implemented on a commercially available Bruker ELEXSYS E580 spectrometer. Room temperature rapid-scan and continuous-wave EPR spectra were recorded for amorphous silicon powder samples. By comparing the resulting signal intensities the feasibility of performing quantitative rapid-scan EPR is demonstrated. For different hydrogenated amorphous silicon samples, rapid-scan EPR results in signal-to-noise improvements by factors between 10 and 50. Rapid-scan EPR is thus capable of improving the detection limit of quantitative EPR by at least one order of magnitude. In addition, we provide a recipe for setting up and calibrating a conventional pulsed and continuous-wave EPR spectrometer for rapid-scan EPR. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Alanine EPR dosimetry of therapeutic irradiators

    International Nuclear Information System (INIS)

    Bugay, O.; Bartchuk, V.; Kolesnik, S.; Mazin, M.; Gaponenko, H.

    1999-01-01

    The high-dose alanine EPR dosimetry is a very precise method in the dose range 1-100 kGy. The system is used generally as the standard high-dose transfer dosimetry in many laboratories. This is comparatively expensive technique so it is important to use it as a more universal dosimetry system also in the middle and low dose ranges. The problems of the middle-dose alanine dosimetry are discussed and the solution of several problems is proposed. The alanine EPR dosimetry has been applied to the dose measurements of medical irradiators in the Kiev City Oncology Center. (author)

  4. Identification of irradiated crab using EPR

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, A. [Radiation Dosimetry Department, National Institute for Standards (NIS), Ministry of Scientific Research, Haram, 12211- Giza, P.O. Box: 136 (Egypt)]. E-mail: maghrabism@yahoo.com

    2007-02-15

    EPR spectroscopy is a fast and powerful technique for the identification of irradiated food. Crab exoskeleton was divided into six parts: dactyl, cheliped, carapace, apron, swimming legs, and walking legs. Samples of the exoskeleton were prepared and irradiated to Cs-137 gamma radiation in the range (1.156-5.365 kGy). EPR spectra of unirradiated as well as irradiated samples were recorded and analyzed. Response to gamma radiation was plotted for each part of the exoskeleton, dactyl was found to be the most sensitive part, followed by the apron (38%), cheliped (37%), walking legs (30%), swimming legs (24%), and carapace (21%) relative to the dactyl response.

  5. Krótka (prehistoria argumentu EPR

    Directory of Open Access Journals (Sweden)

    Tadeusz Pabjan

    2010-12-01

    Full Text Available The 1935 thought experiment of Einstein, Podolsky and Rosen is one of the most important episodes in the history of the dispute about the correct interpretation of quantum mechanics. The present paper deals with the origin of the EPR paper and discusses some other thought experiments that preceded the formulation of the Einstein-Podolsky-Rosen argument. Special attention is paid to the evolution of a simply photon-box experiment, which was devised by Einstein in 1930 and then modified by him several times before 1935. It is argued that the scheme of the original EPR argument is in fact contained in these few seminal experiments.

  6. Biophysical EPR Studies Applied to Membrane Proteins

    Science.gov (United States)

    Sahu, Indra D; Lorigan, Gary A

    2015-01-01

    Membrane proteins are very important in controlling bioenergetics, functional activity, and initializing signal pathways in a wide variety of complicated biological systems. They also represent approximately 50% of the potential drug targets. EPR spectroscopy is a very popular and powerful biophysical tool that is used to study the structural and dynamic properties of membrane proteins. In this article, a basic overview of the most commonly used EPR techniques and examples of recent applications to answer pertinent structural and dynamic related questions on membrane protein systems will be presented. PMID:26855825

  7. Identification of irradiated crab using EPR

    International Nuclear Information System (INIS)

    Maghraby, A.

    2007-01-01

    EPR spectroscopy is a fast and powerful technique for the identification of irradiated food. Crab exoskeleton was divided into six parts: dactyl, cheliped, carapace, apron, swimming legs, and walking legs. Samples of the exoskeleton were prepared and irradiated to Cs-137 gamma radiation in the range (1.156-5.365 kGy). EPR spectra of unirradiated as well as irradiated samples were recorded and analyzed. Response to gamma radiation was plotted for each part of the exoskeleton, dactyl was found to be the most sensitive part, followed by the apron (38%), cheliped (37%), walking legs (30%), swimming legs (24%), and carapace (21%) relative to the dactyl response

  8. TL and EPR dating: some applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil)

    2006-07-01

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  9. Holographic EPR Pairs, Wormholes and Radiation

    OpenAIRE

    Chernicoff, Mariano; Güijosa, Alberto; Pedraza, Juan F.

    2013-01-01

    As evidence for the ER=EPR conjecture, it has recently been observed that the string that is holographically dual to an entangled quark-antiquark pair separating with (asymptotically) uniform acceleration has a wormhole on its worldsheet. We point out that a two-sided horizon and a wormhole actually appear for much more generic quark-antiquark trajectories, which is consistent with the fact that the members of an EPR pair need not be permanently out of causal contact. The feature that determi...

  10. Mast-sipping in EPR trademark plants

    International Nuclear Information System (INIS)

    Langenberger, Jan; Schienbein, Marcel; Geier, Roland

    2010-01-01

    For more than 20 years, AREVA applies and develops different sipping techniques to identify fuel assemblies with leaking fuel rods. For the EPR trademark reactors a Mast Sipping System with newest developments will be implemented considering radiation protection and latest standards requirements. The innovative EPR trademark Sipping System differs from previous systems in many ways. One of the main innovations is that all the necessary processes of the Sipping system have been fully digitized. Second, several ALARA design modifications have been implemented to meet the current radiation protection requirements. An additional implementable multilingual assistance program facilitates the handling of the system and helps to prevent incorrect operation. (orig.)

  11. Design of the EPR containment

    International Nuclear Information System (INIS)

    Appell, B.; Zaiss, W.

    1996-01-01

    In order to respect the safety objectives set for the EPR (European Pressurized water Reactor), the confinement function must be designed to guard against in the design uncontrolled releases in the environment in all conditions taken into account and to preserve its structural integrity. The concept chosen is a double-wall confinement with technology identical derived from the current French N4 containments and the associated systems ensuring the isolation and the control of leaks. The basic principles aiming to minimize leaks are as follows: no direct leak; state-of-the-art leak tight design of the systems and components passing through the containment building; recovery of potential leaks through the inner wall and the penetration sleeves in the inter-wall space; recovery in the peripheral buildings; and specific measures if necessary. The inner wall is a prestressed concrete shell (55 tendons cables arranged in two horizontal layers and a vertical layer for the barrel) without liner, of free volume 90000 m 3 , an internal diameter of 48 m and 1.3 m thickness. The free volume is chosen so as to rule out the risk of global detonation and the use of catalytic recombiners limits the risk of hydrogen explosion. The design pressure (6.5 bar abs) and temperature of the inner wall are defined for a given volume by the set of three conditions: Pee-4 conditions such as LOCA or SLB, global deflagration of hydrogen and core melt scenario. The rate of leakage in accident conditions from the inner wall must not be higher than 1% per day. The chosen concept must enable satisfactory leak tightness to be preserved for beyond design conditions in order to have margins and to guard against phenomenological uncertainties. The possibility of adding an internal composite liner is being studied. A large scale mockup is being built to validate the hypothesis and methods of leak rates of the inner wall and for the performance testing of the composite liner. The outer wall, made of

  12. New strategy to identify radicals in a time evolving EPR data set by multivariate curve resolution-alternating least squares

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, Maya Abou [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France); Juan, Anna de [Chemometrics Group, Section of Analytical Chemistry, Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Vezin, Hervé [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France); Duponchel, Ludovic, E-mail: ludovic.duponchel@univ-lille1.fr [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France)

    2016-12-01

    Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique that is able to characterize radicals formed in kinetic reactions. However, spectral characterization of individual chemical species is often limited or even unmanageable due to the severe kinetic and spectral overlap among species in kinetic processes. Therefore, we applied, for the first time, multivariate curve resolution-alternating least squares (MCR-ALS) method to EPR time evolving data sets to model and characterize the different constituents in a kinetic reaction. Here we demonstrate the advantage of multivariate analysis in the investigation of radicals formed along the kinetic process of hydroxycoumarin in alkaline medium. Multiset analysis of several EPR-monitored kinetic experiments performed in different conditions revealed the individual paramagnetic centres as well as their kinetic profiles. The results obtained by MCR-ALS method demonstrate its prominent potential in analysis of EPR time evolved spectra. - Highlights: • A new strategy to identify radicals in a time evolving EPR data set. • Extraction of pure EPR spectral signatures and corresponding kinetic profiles. • The proposed method does not require any prior knowledge of the chemical system. • A multiset analysis in order to decrease rotational ambiguity.

  13. Optimization of bicelle lipid composition and temperature for EPR spectroscopy of aligned membranes.

    Science.gov (United States)

    McCaffrey, Jesse E; James, Zachary M; Thomas, David D

    2015-01-01

    We have optimized the magnetic alignment of phospholipid bilayered micelles (bicelles) for EPR spectroscopy, by varying lipid composition and temperature. Bicelles have been extensively used in NMR spectroscopy for several decades, in order to obtain aligned samples in a near-native membrane environment and take advantage of the intrinsic sensitivity of magnetic resonance to molecular orientation. Recently, bicelles have also seen increasing use in EPR, which offers superior sensitivity and orientational resolution. However, the low magnetic field strength (less than 1 T) of most conventional EPR spectrometers results in homogeneously oriented bicelles only at a temperature well above physiological. To optimize bicelle composition for magnetic alignment at reduced temperature, we prepared bicelles containing varying ratios of saturated (DMPC) and unsaturated (POPC) phospholipids, using EPR spectra of a spin-labeled fatty acid to assess alignment as a function of lipid composition and temperature. Spectral analysis showed that bicelles containing an equimolar mixture of DMPC and POPC homogeneously align at 298 K, 20 K lower than conventional DMPC-only bicelles. It is now possible to perform EPR studies of membrane protein structure and dynamics in well-aligned bicelles at physiological temperatures and below. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. ENDOR-Induced EPR of Disordered Systems: Application to X-Irradiated Alanine.

    Science.gov (United States)

    Kusakovskij, Jevgenij; Maes, Kwinten; Callens, Freddy; Vrielinck, Henk

    2018-02-15

    The electron paramagnetic resonance (EPR) spectra of radiation-induced radicals in organic solids are generally composed of multiple components that largely overlap due to their similar weak g anisotropy and a large number of hyperfine (HF) interactions. Such properties make these systems difficult to study using standard cw EPR spectroscopy even in single crystals. Electron-nuclear double-resonance (ENDOR) spectroscopy is a powerful and widely used complementary technique. In particular, ENDOR-induced EPR (EIE) experiments are useful for separating the overlapping contributions. In the present work, these techniques were employed to study the EPR spectrum of stable radicals in X-irradiated alanine, which is widely used in dosimetric applications. The principal values of all major proton HF interactions of the dominant radicals were determined by analyzing the magnetic field dependence of the ENDOR spectrum at 50 K, where the rotation of methyl groups is frozen. Accurate simulations of the EPR spectrum were performed after the major components were separated using an EIE analysis. As a result, new evidence in favor of the model of the second dominant radical was obtained.

  15. MDEP Common Position No EPR-01 - Common positions on the EPR instrumentation and controls design

    International Nuclear Information System (INIS)

    2010-01-01

    The purpose of the EPR Working Group (EPRWG) of the Multinational Design Evaluation Program (MDEP) is to identify common positions among the regulators reviewing the EPR Instrumentation and Controls (I and C) Systems in order to: 1. Promote understanding of each country 's regulatory decisions and basis for the decisions, 2. Enhance communication among the members and with external stakeholders, 3. Identify areas where harmonization and convergence of regulations, standards, and guidance can be achieved or improved, and 4. Supports standardization of new reactor designs. Since January 2008, the EPR I and C Technical Expert Subgroup (TESG) members met five times to exchange information regarding their country 's review of the EPR I and C design. The EPR I and C TESG consists of regulators from China, Canada, Finland, France, the United Kingdom, and the United States. The information exchange includes presentation of each country 's review status and technical issues, sharing of guidance documents, and sharing of regulatory decision documents. The TESG focused on the following four core areas of the EPR I and C design: 1. I and C System Independence (particularly for data communications), 2. Level of Defense and Diversity (back-up systems), 3. Qualification/quality of digital platforms, 4. Categorization/classification of systems and functions. As meetings were conducted, some areas were emphasized more depending on the significance of the issues for each country. During the TESG interactions, it became apparent that there were aspects of the EPR design where the countries had common agreement. On November 2, 2009, three of the subgroup countries, France, Finland and the United Kingdom, issued a joint regulatory position on the EPR I and C design as result of the 'Groupe Permanent' meeting in France. This statement of common positions expands upon that joint regulatory position

  16. Polymer therapeutics and the EPR effect.

    Science.gov (United States)

    Maeda, Hiroshi

    History of the EPR (enhanced permeability and retention) effect is discussed, which goes back to the analyses of molecular pathology in bacterial infection and edema (extravasation) formation. The first mediator we found for extravasation was bradykinin. Later on, were found nitric oxide and superoxide, then formation of peroxynitrite, that activates procollagenase. In this inflammatory setting many other vascular mediators are involved that are also common to cancer vasculature. Obviously cancer vasculature is defective architechtally, and this makes macromolecular drugs more permeable through the vascular wall. The importance of this pathophysiological event of EPR effect can be applied to macromolecular drug-delivery, or tumor selective delivery, which takes hours to achieve in the primary as well as metastatic tumors, not to mention of the inflamed tissues. The retention of the EPR means that such drugs will be retained in tumor tissues more than days to weeks. This was demonstrated initially, and most dramatically, using SMANCS, a protein-polymer conjugated-drug dissolved in lipid contrast medium (Lipiodol) by administering intraarterially. For disseminating the EPR concept globally, or in the scientific community, Professor Ruth Duncan played a key role at the early stage, as she worked extensively on polymer- therapeutics, and knew its importance.

  17. Teaching the EPR Paradox at High School?

    Science.gov (United States)

    Pospiech, Gesche

    1999-01-01

    Argues the importance of students at university and in the final years of high school gaining an appreciation of the principles of quantum mechanics. Presents the EPR gedanken experiment (thought experiment) as a method of teaching the principles of quantum mechanics. (Author/CCM)

  18. EPR-dosimetry of ionizing radiation

    Science.gov (United States)

    Popova, Mariia; Vakhnin, Dmitrii; Tyshchenko, Igor

    2017-09-01

    This article discusses the problems that arise during the radiation sterilization of medical products. It is propose the solution based on alanine EPR-dosimetry. The parameters of spectrometer and methods of absorbed dose calculation are given. In addition, the problems that arise during heavy particles irradiation are investigated.

  19. Clinical EPR: Unique Opportunities and Some Challenges

    Science.gov (United States)

    Swartz, Harold M.; Williams, Benjamin B.; Zaki, Bassem I.; Hartford, Alan C.; Jarvis, Lesley A.; Chen, Eunice; Comi, Richard J.; Ernstoff, Marc S.; Hou, Huagang; Khan, Nadeem; Swarts, Steven G.; Flood, Ann B.; Kuppusamy, Periannan

    2014-01-01

    Electron paramagnetic resonance (EPR) spectroscopy has been well established as a viable technique for measurement of free radicals and oxygen in biological systems, from in vitro cellular systems to in vivo small animal models of disease. However, the use of EPR in human subjects in the clinical setting, although attractive for a variety of important applications such as oxygen measurement, is challenged with several factors including the need for instrumentation customized for human subjects, probe and regulatory constraints. This paper describes the rationale and development of the first clinical EPR systems for two important clinical applications, namely, measurement of tissue oxygen (oximetry), and radiation dose (dosimetry) in humans. The clinical spectrometers operate at 1.2 GHz frequency and use surface loop resonators capable of providing topical measurements up to 1 cm depth in tissues. Tissue pO2 measurements can be carried out noninvasively and repeatedly after placement of an oxygen-sensitive paramagnetic material (currently India ink) at the site of interest. Our EPR dosimetry system is capable of measuring radiation-induced free radicals in the tooth of irradiated human subjects to determine the exposure dose. These developments offer potential opportunities for clinical dosimetry and oximetry, which include guiding therapy for individual patients with tumors or vascular disease, by monitoring of tissue oxygenation. Further work is in progress to translate this unique technology to routine clinical practice. PMID:24439333

  20. EPR application in medicine and biology

    Czech Academy of Sciences Publication Activity Database

    Stopka, Pavel; Křížová, Jana; Káfuňková, Eva

    2005-01-01

    Roč. 99, č. 14 (2005), s. 190-192 ISSN 0009-2770 R&D Projects: GA MZd(CZ) NB7377; GA MZd(CZ) NL7567 Institutional research plan: CEZ:AV0Z40320502 Keywords : EPR application Subject RIV: CA - Inorganic Chemistry Impact factor: 0.445, year: 2005

  1. Zavoisky and the Discovery of EPR

    Indian Academy of Sciences (India)

    IAS Admin

    moved to Kazan. In 1926, after finishing the nine-year secondary ... year student, he got a patent for an invention. Zavoisky was ... Early Attempts at NMR and Interruption by World War II ... band modulation) and, in some cases, he did not even apply the constant ... was awarded the Lenin Prize for the discovery of EPR. In the.

  2. The EPR detection of radiation treated foodstuffs

    International Nuclear Information System (INIS)

    Stachowicz, W.; Burlinska, G.; Michalik, J.; Ostrowski, K.; Dziedzic-Goclawska, A.

    1993-01-01

    The short paper by a Polish study group describes the results of the use of Electron Paramagnetic Resonance (EPR) Spectroscopy in the detection of irradiation to food. Pultry, fresh-water fish and sea fish as well as various fruits and yellow boletus are dealt with in some detail. (VHE) [de

  3. New Generation of self-calibrated SS/EPR dosimeters: Alanine/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    A new type of solid state/EPR dosimeters is described. Principally, it contains radiation sensitive diamagnetic material, some quantity of EPR active, but radiation insensitive, substance (for example Mn 2+ /MgO) and a binding material. In the present case alanine is used as a radiation sensitive substance. With this dosimeter, the EPR spectra of alanine and Mn 2+ are simultaneously recorded and the calibration graph represents the ratio of alanine versus Mn 2+ EPR signal intensity as a function of absorbed dose. In this way the reproducibility of the results is expected to be improved significantly including their intercomparison among different laboratories. Homogeneity of the prepared dosimeters and their behaviour (fading of EPR signals with time, influence of different meteorological conditions) show satisfactory reproducibility and stability with time. Because two different EPR active samples are recorded simultaneously, the influence of some instrument setting parameters (microwave power, modulation amplitude and modulation frequency) on the ratio I alanine /I Mn is also investigated. (author)

  4. Soil class around me Serpong experimental power reactor (EPR) site plan base on micro tremor data

    International Nuclear Information System (INIS)

    Marjiyono; Soehaimi A; Hadi Suntoko; Yuliastuti; Syaeful H

    2015-01-01

    Surface geological characteristics has an important role on site response analysis in a region. In regard with experimental power reactor (EPR) construction plan in Serpong, the subsurface modeling from combination array and single station micro tremor data was done. The array and single station micro tremor measurement were performed in 9 and 90 sites, respectively, at ± 1 km radius around the EPR site plan. The Vs30 value was calculated from shear wave velocity structure around the investigated area. The soil classification based on Vs30 in the investigated area generally consists of SD (medium soil) and SC (soft rock) class. The EPR site plan its self in the SD class region. (author)

  5. Assessment of performance parameters for EPR dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Wieser, A.; Fattibene, P.; Shishkina, E.A.; Ivanov, D.V.; De Coste, V.; Guettler, A.; Onori, S.

    2008-01-01

    In the framework of a comparison between three laboratories, electron paramagnetic resonance (EPR) signal-to-dose response curves were measured for sets of 30 tooth enamel samples and the variance of EPR measurements in dependence on absorbed dose was evaluated, in nine combinations of laboratory of sample preparation and EPR evaluation, respectively. As a test for benchmarking of EPR evaluation, the parameters 'critical dose' and 'limit of detection' were proposed as performance parameters following definitions from chemical-metrology, and a model function was suggested for analytical formulation of the dependence of the variance of EPR measurement on absorbed dose. First estimates of limits of detection by weighted and unweighted fitting resulted in the range 101-552 and 67-561 mGy, respectively, and were generally larger with weighted than with unweighted fitting. Indication was found for the influence of methodology of sample preparation and applied EPR measurement parameters on performance of EPR dosimetry with tooth enamel

  6. Forming and detection of digital watermarks in the System for Automatic Identification of VHF Transmissions

    Directory of Open Access Journals (Sweden)

    О. В. Шишкін

    2013-07-01

    Full Text Available Forming and detection algorithms for digital watermarks are designed for automatic identification of VHF radiotelephone transmissions in the maritime and aeronautical mobile services. An audible insensitivity and interference resistance of embedded digital data are provided by means of OFDM technology jointly with normalized distortions distribution and data packet detection by the hash-function. Experiments were carried out on the base of ship’s radio station RT-2048 Sailor and USB ADC-DAC module of type Е14-140M L-CARD in the off-line processing regime in Matlab medium

  7. EPR Study of Vanadium Ion in Zinc-Boro-Vanadate Glasses

    International Nuclear Information System (INIS)

    Renuka, C.; Gowda, V. C. Veeranna; Chakradhar, R. P. S.; Reddy, C. Narayana

    2011-01-01

    This paper describes EPR studies on x V 2 O 5 -(40-x)ZnO-60B 2 O 3 (where x 5, 10, 15 and 20 mol %) glass system. These studies indicate a strong compositional dependent trend and existence of characteristic boro-vanadate groups in these glasses. The EPR spectra show a distinct hyperfine structure of 51 V. Spectral analysis shows that the vanadium is present in the glass as vanadyl ion [VO] 2+ at tetragonally distorted octahedral site. The decrease of A || and A perpendicular with increase of V 2 O 5 concentration suggests an increase in the covalence between the central atom and the surrounding oxygen ligands.

  8. Characterization of KCNE1 inside Lipodisq Nanoparticles for EPR Spectroscopic Studies of Membrane Proteins.

    Science.gov (United States)

    Sahu, Indra D; Zhang, Rongfu; Dunagan, Megan M; Craig, Andrew F; Lorigan, Gary A

    2017-06-01

    EPR spectroscopic studies of membrane proteins in a physiologically relevant native membrane-bound state are extremely challenging due to the complexity observed in inhomogeneity sample preparation and dynamic motion of the spin-label. Traditionally, detergent micelles are the most widely used membrane mimetics for membrane proteins due to their smaller size and homogeneity, providing high-resolution structure analysis by solution NMR spectroscopy. However, it is often difficult to examine whether the protein structure in a micelle environment is the same as that of the respective membrane-bound state. Recently, lipodisq nanoparticles have been introduced as a potentially good membrane mimetic system for structural studies of membrane proteins. However, a detailed characterization of a spin-labeled membrane protein incorporated into lipodisq nanoparticles is still lacking. In this work, lipodisq nanoparticles were used as a membrane mimic system for probing the structural and dynamic properties of the integral membrane protein KCNE1 using site-directed spin labeling EPR spectroscopy. The characterization of spin-labeled KCNE1 incorporated into lipodisq nanoparticles was carried out using CW-EPR titration experiments for the EPR spectral line shape analysis and pulsed EPR titration experiment for the phase memory time (T m ) measurements. The CW-EPR titration experiment indicated an increase in spectral line broadening with the addition of the SMA polymer which approaches close to the rigid limit at a lipid to polymer weight ratio of 1:1, providing a clear solubilization of the protein-lipid complex. Similarly, the T m titration experiment indicated an increase in T m values with the addition of SMA polymer and approaches ∼2 μs at a lipid to polymer weight ratio of 1:2. Additionally, CW-EPR spectral line shape analysis was performed on six inside and six outside the membrane spin-label probes of KCNE1 in lipodisq nanoparticles. The results indicated significant

  9. Loads on EPR containment after RPV failure at high pressure

    International Nuclear Information System (INIS)

    Jacobs, G.

    1995-01-01

    As regards the desgin of the EPR, the general strategy is to eliminate, the vessel failure at high pressure by preventive and mitigative measures. The design proposals involved trust in the reliability of dedicated devices (relief valves) for rapid depressurization. The aim is to attain a lower pressure level at the moment of vessel failure, so that the containment is capable to cope with the blowdown impact on the pit walls and the vessel supporting structures. Nevertheless, the potential of a high-pressure failure of the vessel must be kept in mind, whatever well thought-out and reliable preventive depressurization measures might be. Therefore, the reactor pressure blowdown has been studied in order to quantify the ultimate containment load, which might support future design requirements. The calculations were performed with the LWR transient analysis thermal-hydraulics computer code REALAP5/MOD3. In previous analyses, the nodalization of the problem was based on the geometrical conditions of a typical German 1300 MW(e) NPP. In the present analysis a new input model has been used, which was based on the EPR conditions. (orig./HP)

  10. Two-dimensional simulations of multi-hollow VHF SiH4/H2 plasma

    Directory of Open Access Journals (Sweden)

    Li-Wen Su

    2018-02-01

    Full Text Available A triode multi-hollow VHF SiH4/H2 plasma (60 MHz was examined at a pressure of 20 Pa by two-dimensional simulations using the fluid model. In this study, we considered the effect of the rate constant of reaction, SiH3 + SiH3→SiH2 + SiH4, on the plasma characteristics. A typical VHF plasma of a high-electron density with a low-electron temperature was obtained between two discharge electrodes. Spatial profiles of SiH3+, SiH2+, SiH3- and SiH3 densities were similar to that of the electron density while the electron temperature had a maximum value near the two discharge electrodes. It was found that the SiH3 radical density did not decrease rapidly near the substrate and the electron temperature was lower than 1 eV, suggesting that the triode multi-hollow plasma source can provide high quality amorphous silicon with a high deposition rate.

  11. VHF/UHF radar observations of tropical mesoscale convective systems over southern India

    Directory of Open Access Journals (Sweden)

    K. Kishore Kumar

    2005-07-01

    Full Text Available Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E, a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other.

    Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes – Radio science (Remote sensing

  12. VHF/UHF radar observations of tropical mesoscale convective systems over southern India

    Directory of Open Access Journals (Sweden)

    K. Kishore Kumar

    2005-07-01

    Full Text Available Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E, a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes – Radio science (Remote sensing

  13. VHF/UHF imagery and RCS measurements of ground targets in forested terrain

    Science.gov (United States)

    Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Waldman, Jerry; Nixon, William E.

    2002-08-01

    The monostatic VV and HH-polarized radar signatures of several targets and trees have been measured at foliage penetration frequencies (VHF/UHF) by using 1/35th scale models and an indoor radar range operating at X-band. An array of high-fidelity scale model ground vehicles and test objects as well as scaled ground terrain and trees have been fabricated for the study. Radar measurement accuracy has been confirmed by comparing the signature of a test object with a method of moments radar cross section prediction code. In addition to acquiring signatures of targets located on a smooth, dielectric ground plane, data have also been acquired with targets located in simulated wooded terrain that included scaled tree trunks and tree branches. In order to assure the correct backscattering behavior, all dielectric properties of live tree wood and moist soil were scaled properly to match the complex dielectric constant of the full-scale materials. The impact of the surrounding tree clutter on the VHF/UHF radar signatures of ground vehicles was accessed. Data were processed into high-resolution, polar-formatted ISAR imagery and signature comparisons are made between targets in open-field and forested scenarios.

  14. In situ occupational and general public exposure to VHF/UHF transmission for air traffic communication.

    Science.gov (United States)

    Joseph, Wout; Goeminne, Francis; Verloock, Leen; Vermeeren, Günter; Martens, Luc

    2012-09-01

    Occupational and general public exposure due to very high frequency (VHF)/ultra high frequency (UHF) transmission centres for verbal communication for air traffic control is investigated in situ for the first time. These systems are used for communication with aircraft, resulting in different human exposure from that of classical broadcasting. Measurement methods are proposed for the exposure assessment, and a measurement campaign is executed in three transmission centres. By investigating the temporal behaviour of the VHF signals for 6 d, a realistic worst-case duty cycle of 29 % is determined. Periods of high exposures corresponding with high aircraft traffic are from 7 a.m. to 1 p.m. and in the evening. All measured electric-field values satisfy the International Commission on Non-ionizing Radiation Protection guidelines. Fields vary from 0.2 to 21.1 V m(-1) for occupational exposure and from 0.007 to 8.0 V m(-1) for general public exposure. The average fields equal 5.2 V m(-1) for workers, and 0.7 V m(-1) for general public.

  15. In situ occupational and general public exposure to VHF/UHF transmission for air traffic communication

    International Nuclear Information System (INIS)

    Joseph, W.; Goeminne, F.; Verloock, L.; Vermeeren, G.; Martens, L.

    2012-01-01

    Occupational and general public exposure due to very high frequency (VHF)/ultra high frequency (UHF) transmission centres for verbal communication for air traffic control is investigated in situ for the first time. These systems are used for communication with aircraft, resulting in different human exposure from that of classical broadcasting. Measurement methods are proposed for the exposure assessment, and a measurement campaign is executed in three transmission centres. By investigating the temporal behaviour of the VHF signals for 6 d, a realistic worst-case duty cycle of 29 % is determined. Periods of high exposures corresponding with high aircraft traffic are from 7 a.m. to 1 p.m. and in the evening. All measured electric field values satisfy the International Commission on Non-ionizing Radiation Protection guidelines. Fields vary from 0.2 to 21.1 V m -1 for occupational exposure and from 0.007 to 8.0 V m -1 for general public exposure. The average fields equal 5.2 V m -1 for workers, and 0.7 V m -1 for general public. (authors)

  16. EPR Studies of Spin-Spin Exchange Processes: A Physical Chemistry Experiment.

    Science.gov (United States)

    Eastman, Michael P.

    1982-01-01

    Theoretical background, experimental procedures, and analysis of experimental results are provided for an undergraduate physical chemistry experiment on electron paramagnetic resonance (EPR) linewidths. Source of line broadening observed in a spin-spin exchange process between radicals formed in aqueous solutions of potassium peroxylamine…

  17. Quality assessment of information about medications in primary care electronic patient record (EPR systems

    Directory of Open Access Journals (Sweden)

    Maria Pous

    2010-06-01

    Conclusions This project highlighted the poor quality of drug information provided by these EPR programmes. The ten-item tool seems suitable for assessing their quality. Based on this analysis, we have proposed a set of ten quality standards for prescribing software.

  18. Effect of ferroelastic domain pattern changes on the EPR spectra in TDM

    Science.gov (United States)

    Zapart, W.; Zapart, M. B.

    2011-09-01

    This article presents polarized light microscopy studies of the ferroelastic domain structure and the analysis of electron paramagnetic resonance spectra of Cr3+ admixture ions in trigonal double molybdates. The correlation has been found between abnormal EPR lineshape and domain structure in ferroelastic phases of these crystals.

  19. Study of EPR spectra of radicals from ionizing radiation interaction with alanine and 4-hydroxyproline samples

    International Nuclear Information System (INIS)

    Simion, Corina Anca; Georgescu, Rodica; Grigorescu, Eric Leon

    2006-01-01

    A number of stable chemical radicals result following irradiation with ionizing rays of α-β-alanine and 4-hydroxyproline. They could be put into evidence using post-irradiation EPR technique. Analysis and inter-comparison of spectra signals become important for a correct assignment of structure and, subsequently of generating mechanisms in amino acids irradiated samples. (author)

  20. Detection of Redox Imbalance in Normal Lymphocytes with Induced Mitochondrial Dysfunction - EPR Study.

    Science.gov (United States)

    Georgieva, Ekaterina; Zhelev, Zhivko; Aoki, Ichio; Bakalova, Rumiana; Higashi, Tatsuya

    2016-10-01

    The present study describes a new approach for direct imaging of redox status in live cells using paramagnetic spin-probes, which allows evaluation of the level of oxidative stress due to overproduction of superoxide. The method is based on redox cycling of cell/mitochondria-penetrating nitroxide radicals (e.g. mito-TEMPO) and their electron-paramagnetic resonance (EPR) contrast, which makes them useful molecular sensors for analysis of redox status and oxidative stress in cells and tissues. Oxidative stress was induced in normal human lymphocytes by treatment with 2-methoxyestradiol and rotenone (ME/Rot) at different concentrations. This combination provokes mitochondrial dysfunction, which is accompanied by overproduction of superoxide. The EPR measurements were performed in dynamics on X-Band spectrometer after addition of mito-TEMPO to cell suspensions. The intensity of the EPR signal in untreated cells decreased significantly, which indicates a conversion of paramagnetic mito-TEMPO to its non-contrast diamagnetic form (hydroxylamine - mito-TEMPOH) due to reduction. In ME/Rot-treated cells, the signal decreased more slowly and to a lower level with increasing the concentration of ME/Rot. These data indicate an induction of oxidative stress in the cells in a concentration-dependent manner. A very good positive correlation between the intensity of EPR signal of mito-TEMPO and the intracellular level of superoxide was found, analyzed by conventional dihydroethidium test (R=0.9143, pEPR imaging of the superoxide level in live cells, as well as for EPR imaging of mitochondrial dysfunction and metabolic activity, accompanied by superoxide imbalance. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  1. Full cycle rapid scan EPR deconvolution algorithm.

    Science.gov (United States)

    Tseytlin, Mark

    2017-08-01

    Rapid scan electron paramagnetic resonance (RS EPR) is a continuous-wave (CW) method that combines narrowband excitation and broadband detection. Sinusoidal magnetic field scans that span the entire EPR spectrum cause electron spin excitations twice during the scan period. Periodic transient RS signals are digitized and time-averaged. Deconvolution of absorption spectrum from the measured full-cycle signal is an ill-posed problem that does not have a stable solution because the magnetic field passes the same EPR line twice per sinusoidal scan during up- and down-field passages. As a result, RS signals consist of two contributions that need to be separated and postprocessed individually. Deconvolution of either of the contributions is a well-posed problem that has a stable solution. The current version of the RS EPR algorithm solves the separation problem by cutting the full-scan signal into two half-period pieces. This imposes a constraint on the experiment; the EPR signal must completely decay by the end of each half-scan in order to not be truncated. The constraint limits the maximum scan frequency and, therefore, the RS signal-to-noise gain. Faster scans permit the use of higher excitation powers without saturating the spin system, translating into a higher EPR sensitivity. A stable, full-scan algorithm is described in this paper that does not require truncation of the periodic response. This algorithm utilizes the additive property of linear systems: the response to a sum of two inputs is equal the sum of responses to each of the inputs separately. Based on this property, the mathematical model for CW RS EPR can be replaced by that of a sum of two independent full-cycle pulsed field-modulated experiments. In each of these experiments, the excitation power equals to zero during either up- or down-field scan. The full-cycle algorithm permits approaching the upper theoretical scan frequency limit; the transient spin system response must decay within the scan

  2. Steering, Entanglement, Nonlocality, and the EPR Paradox

    Science.gov (United States)

    Wiseman, Howard; Jones, Steve; Andrew, Doherty

    2007-06-01

    The concept of steering was introduced by Schroedinger in 1935 as a generalization of the EPR paradox for arbitrary pure bipartite entangled states and arbitrary measurements by one party. Until now, it has never been rigorously defined, so it has not been known (for example) what mixed states are steerable (that is, can be used to exhibit steering). We provide an operational definition, from which we prove (by considering Werner states and Isotropic states) that steerable states are a strict subset of the entangled states, and a strict superset of the states that can exhibit Bell-nonlocality. For arbitrary bipartite Gaussian states we derive a linear matrix inequality that decides the question of steerability via Gaussian measurements, and we relate this to the original EPR paradox.

  3. The long way to the EPR

    International Nuclear Information System (INIS)

    Berke, C.

    1997-01-01

    At the joint conference organized by the German Kerntechnische Gesellschaft (KTG) e.V. and the French Societe Francaise d'Energie Nucleaire (SFEN) in Cologne, the announcement was made on October 20, 1997 that Jean Claude Leny will be appointed Honorary Member of KTG. For reasons of ill health the new honorary member was prevented from attending the conference. In his place, Claus Berke sketched the history of the European Pressurized Water Reactor (EPR) and presented an overview of nuclear development in France and in Germany. Developing one standard reactor model in the primary objective of German-French cooperation in reactor development. The EPR is to replace the present nuclear generating units in France and Germany after the end of their planned service life, and is to be marketed as a standard export line. (orig.) [de

  4. EPR becomes reality at Finland's Olkiluoto 3

    International Nuclear Information System (INIS)

    Gueldner, R.; Giese, U.

    2005-01-01

    The EPR is a third-generation pressurized water reactor (PWR). Its development was started in 1992 by Framatome and Siemens within a Franco-German partnership. Since 2001 this work has been continued by Framatome ANP, which was formed when the two companies merged their nuclear businesses. The French company AREVA, world market leader in nuclear technology, holds a 66% share in Framatome ANP, with Siemens owning 34%. From the very start, development of the EPR was focused on improving plant safety and economics even further. The new reactor development was jointly financed together with the leading power utilities of both countries. The first steps towards realization of an EPR nuclear power plant were taken at Olkiluoto, Finland in 2004, consisting of initial preparation of the construction site. By mid-February 2005 the local municipality - Eurajoki - had issued a construction permit, and the Finnish Government a construction license pursuant to the Finnish Nuclear Energy Act. This had been preceded by a preliminary safety assessment prepared by the Finnish Radiation and Nuclear Safety Authority (STUK) for the Finnish Ministry of Trade and Industry in which STUK verified that it did not see any safety-related issues opposing issuance of the nuclear construction license. STUK emphasized that the evolutionary design of the EPR had been further improved by AREVA compared to the previous product lines. Concreting work began this spring and the unit will start commercial operation in 2009. Construction of an EPR has also been given the political go-ahead in France. According to the utility Electricite de France (EDF) the new reactor will be built as a forerunner of a later series at the site of Flamanville in Normandy. Construction is scheduled to begin in 2007. An EPR nuclear power plant has a rated electric capacity of around 1600 MW, depending on specific site conditions. Being the product of intense bilateral cooperation the EPR combines the technological

  5. A theoretical interpretation of EPR and ENDOR

    International Nuclear Information System (INIS)

    Matos, M.O.M. de.

    1975-08-01

    To interpret the EPR and ENDOR results of the U 2 center in SrF 2 , two wavefunctions are proposed to describe the unpaired electron of the defect. Use is made of two different models in order to obtain the wavefunctions: the Heitler-London and that of molecular orbitals models. The Pauli repulsion (overlap of wavefunctions) is discussed as well as covalency mechanisms and their influence in the calculation of the hyperfine constants due to magnetic interaction of the unpaired electron and the magnetic nucleus of the cristal. A small amount of covalency between the ground state of the interstitial Hydrogen atom and the 2p shell of the F - ions of the first cristaline shell is introduced fenomenologically in the molecular orbitals model. Both methods are discussed by comparing the theoretical calculations of the hyperfine constants with the measured experimental values obtained with the EPR and ENDOR techniques. (Author) [pt

  6. Holographic EPR pairs, wormholes and radiation

    Science.gov (United States)

    Chernicoff, Mariano; Güijosa, Alberto; Pedraza, Juan F.

    2013-10-01

    As evidence for the ER = EPR conjecture, it has recently been observed that the string that is holographically dual to an entangled quark-antiquark pair separating with (asymptotically) uniform acceleration has a wormhole on its worldsheet. We point out that a two-sided horizon and a wormhole actually appear for much more generic quark-antiquark trajectories, which is consistent with the fact that the members of an EPR pair need not be permanently out of causal contact. The feature that determines whether the causal structure of the string worldsheet is trivial or not turns out to be the emission of gluonic radiation by the dual quark and antiquark. In the strongly-coupled gauge theory, it is only when radiation is emitted that one obtains an unambiguous separation of the pair into entangled subsystems, and this is what is reflected on the gravity side by the existence of the worldsheet horizon.

  7. Multisite EPR oximetry from multiple quadrature harmonics.

    Science.gov (United States)

    Ahmad, R; Som, S; Johnson, D H; Zweier, J L; Kuppusamy, P; Potter, L C

    2012-01-01

    Multisite continuous wave (CW) electron paramagnetic resonance (EPR) oximetry using multiple quadrature field modulation harmonics is presented. First, a recently developed digital receiver is used to extract multiple harmonics of field modulated projection data. Second, a forward model is presented that relates the projection data to unknown parameters, including linewidth at each site. Third, a maximum likelihood estimator of unknown parameters is reported using an iterative algorithm capable of jointly processing multiple quadrature harmonics. The data modeling and processing are applicable for parametric lineshapes under nonsaturating conditions. Joint processing of multiple harmonics leads to 2-3-fold acceleration of EPR data acquisition. For demonstration in two spatial dimensions, both simulations and phantom studies on an L-band system are reported. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Teichmuller Space Resolution of the EPR Paradox

    Science.gov (United States)

    Winterberg, Friedwardt

    2013-04-01

    The mystery of Newton's action-at-a-distance law of gravity was resolved by Einstein with Riemann's non-Euclidean geometry, which permitted the explanation of the departure from Newton's law for the motion of Mercury. It is here proposed that the similarly mysterious non-local EPR-type quantum correlations may be explained by a Teichmuller space geometry below the Planck length, for which an experiment for its verification is proposed.

  9. Steering, Entanglement, Nonlocality, and the EPR Paradox

    OpenAIRE

    Wiseman, H. M.; Jones, S. J.; Doherty, A. C.

    2006-01-01

    The concept of steering was introduced by Schrodinger in 1935 as a generalization of the EPR paradox for arbitrary pure bipartite entangled states and arbitrary measurements by one party. Until now, it has never been rigorously defined, so it has not been known (for example) what mixed states are steerable (that is, can be used to exhibit steering). We provide an operational definition, from which we prove (by considering Werner states and Isotropic states) that steerable states are a strict ...

  10. Seventy Years of the EPR Paradox

    Science.gov (United States)

    Kupczynski, Marian

    2006-11-01

    In spite of the fact that statistical predictions of quantum theory (QT) can only be tested if large amount of data is available a claim has been made that QT provides the most complete description of an individual physical system. Einstein's opposition to this claim and the paradox he presented in the article written together with Podolsky and Rosen in 1935 inspired generations of physicists in their quest for better understanding of QT. Seventy years after EPR article it is clear that without deep understanding of the character and limitations of QT one may not hope to find a meaningful unified theory of all physical interactions, manipulate qubits or construct a quantum computer.. In this paper we present shortly the EPR paper, the discussion, which followed it and Bell inequalities (BI). To avoid various paradoxes we advocate purely statistical contextual interpretation (PSC) of QT. According to PSC a state vector is not an attribute of a single electron, photon, trapped ion or quantum dot. A value of an observable assigned to a physical system has only a meaning in a context of a particular physical experiment PSC does not provide any mental space-time picture of sub phenomena. The EPR paradox is avoided because the reduction of the state vector in the measurement process is a passage from a description of the whole ensemble of the experimental results to a particular sub-ensemble of these results. We show that the violation of BI is neither a proof of the completeness of QT nor of its non-locality. Therefore we rephrase the EPR question and ask whether QT is "predictably "complete or in other words does it provide the complete description of experimental data. To test the "predictable completeness" it is not necessary to perform additional experiments it is sufficient to analyze more in detail the existing experimental data by using various non-parametric purity tests and other specific statistical tools invented to study the fine structure the time-series.

  11. Seventy Years of the EPR Paradox

    OpenAIRE

    Kupczynski, Marian

    2007-01-01

    In spite of the fact that statistical predictions of quantum theory (QT) can only be tested if large amount of data is available a claim has been made that QT provides the most complete description of an individual physical system. Einstein's opposition to this claim and the paradox he presented in the article written together with Podolsky and Rosen in 1935 inspired generations of physicists in their quest for better understanding of QT. Seventy years after EPR article it is clear that witho...

  12. Is the EPR paradox really a paradox?

    OpenAIRE

    Tartaglia, A.

    1998-01-01

    The EPR paradox and the meaning of the Bell inequality are discussed. It is shown that considering the quantum objects as carrying with them ''instruction kits'' telling them what to do when meeting a measurement apparatus any paradox disappears. In this view the quantum state is characterized by the prescribed behaviour rather than by the specific value a parameter assumes as a result of an interaction.

  13. Should the EPR be financed by industrialists?

    International Nuclear Information System (INIS)

    Jemain, A.

    2005-01-01

    As a reciprocal arrangement, the industrialists should be invited to contribute to the financing of the new generation reactor EPR (European pressurized reactor) which will be built in Flamanville (Manche, France). In exchange to their financial participation, the industrialists will receive the contractual warranty of stable electricity prices during 10 to 15 years periods. This short paper presents the opposite opinion of two representative of French industries concerning this proposal. Short paper. (J.S.)

  14. EPR Test with Photons and Kaons Analogies

    CERN Document Server

    Gisin, Nicolas

    2001-01-01

    We present a unified formalism describing EPR test using spin 1/2 particles, photons and kaons. This facilitates the comparison between existing experiments using photons and kaons. It underlines the similarities between birefringence and polarization dependent losses that affects experiments using optical fibers and mixing and decay that are intrinsic to the kaons. We also discuss the limitation these two characteristics impose on the testing of Bell's inequality.

  15. On Popper's new EPR-Experiment

    International Nuclear Information System (INIS)

    Bedford, D.; Selleri, F.

    1985-01-01

    It is scientifically reasonable to search for particular statistical ensembles to which the standard quantum rules (like Heisenberg relations) do not apply: these rules would instead be applicable to more general statistical ensembles (which might be called ''standard quantum ensembles''). Along these lines, Popper has recently proposed what he calls ''a new version of the EPR experiment'' in which the Copenhagen and statistical interpretations of quantum mechanics apparently lead to distinguishably different predictions

  16. The Finnish EPR dependent on a bridge

    International Nuclear Information System (INIS)

    Dupin, L.

    2010-01-01

    A new conflict has emerged between the main contractor Areva and its client TVO, the Finnish energy group. The qualification of a handling bridge has delayed the OL3 project of third EPR reactor at Olkiluoto, Finland. The disagreement concerns the testing procedure and may induce a two year delay in the completion of the project which is now planned for 2012 instead of 2010 initially. (J.S.)

  17. The EPR operators are trained on simulator

    International Nuclear Information System (INIS)

    Maincent, G.

    2009-01-01

    Three years before the EPR reactor of Flamanville (Normandie, France) is generating its very first kilowatt hours, Electricite de France has started to train its teams on a simulator which reproduces the man-machine interface of the future nuclear power plant. The simulator used is an evolutive tool specific to the Flamanville reactor and capable to test about 20 different accidental situations. (J.S.)

  18. EPR in non-doped irradiated polyacetylene

    International Nuclear Information System (INIS)

    Hola, O.; Stasko, A.; Foeldesova, M.

    1993-01-01

    The influence of γ-irradiation on the paramagnetic properties of non-doped polyacetylene at low and high radiation doses has been studied and summarized. The dependence of the EPR spectra on the radiation dose in irradiated polyacetylene has been measured. No essential changes of the spin mobility as a consequence of irradiation were observed. The measurements of spin concentration confirm the high resistivity of non-doped polyacetylene to radiation. (author) 9 refs

  19. ISS protocol for EPR tooth dosimetry

    International Nuclear Information System (INIS)

    Onori, S.; Aragno, D.; Fattibene, P.; Petetti, E.; Pressello, M.C.

    2000-01-01

    The accuracy in Electron Paramagnetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in the framework of the European Community Nuclear Fission Safety project 'Dose Reconstruction' is presented. A combined mechanical-chemical procedure for ground enamel sample preparation is used. The signal intensity evaluation is carried out with powder spectra simulation program. Finally, the unknown dose is evaluated individually for each sample with the additive dose method. The unknown dose is obtained by subtracting a mean native dose from the back-extrapolated dose. As an example of the capability of the ISS protocol in unknown dose evaluation, the results obtained in the framework of the 2nd International Intercomparison on EPR tooth enamel dosimetry are reported

  20. Active or passive systems? The EPR approach

    International Nuclear Information System (INIS)

    Bonhomme, N.; Py, J.P.

    1996-01-01

    In attempting to review how EPR is contemplated to meet requirements applicable to future nuclear power plants, the authors indicate where they see the markets and the corresponding unit sizes for the EPR which is a generic key factor for competitiveness. There are no reason in industrialized countries, other than USA (where the investment and amortizing practices under control by Public Utility Commission are quite particular), not to build future plants in the 1000 to 1500 MWe range. Standardization, which has been actively applied all along the French program and for the Konvoi plants, does not prevent evolution and allows to concentrate large engineering effort in smooth realization of plants and achieve actual construction and commissioning without significant delays. In order to contribute to public trust renewal, a next generation of power reactors should be fundamentally less likely to incur serious accidents. To reach this goal the best of passive and active systems must be considered without forgetting that the most important source of knowledge is construction and operating experience. Criteria to assess passive systems investigated for possible implementation in the EPR, such as simplicity of design, impact on plant operation, safety and cost, are discussed. Examples of the principal passive systems investigated are described and reasons why they have been dropped after screening through the criteria are given. (author). 11 figs

  1. Comparative study of some new EPR dosimeters

    International Nuclear Information System (INIS)

    Alzimami, K.S.; Maghraby, Ahmed M.; Bradley, D.A.

    2014-01-01

    Investigations have been made of four new radiation dosimetry EPR candidates from the same family of materials: sulfamic acid, sulfanillic acid, homotaurine, and taurine. Mass energy attenuation coefficients, mass stopping power values and the time dependence of the radiation induced radicals are compared. Also investigated are the microwave saturation behavior and the effect of applied modulation amplitude on both peak-to-peak line width (W PP ) and peak-to-peak signal height (H PP ). The dosimeters are characterized by simple spectra and stable radiation-induced radicals over reasonable durations, especially in taurine dosimeters. Sulfamic acid dosimeters possessed the highest sensitivity followed by taurine and homotaurine and sulfanillic. - Highlights: ► Several EPR dosimeters were suggested based on SO 3 − radical. ► Taurine, homotaurine, sulfanilic, and sulfamic acid all possess simple EPR spectra. ► Dosimeters were compared to each other in terms of the dosimetric point of view. ► Energy dependence curves of the selected dosimeters were compared to eachother

  2. Active or passive systems? The EPR approach

    Energy Technology Data Exchange (ETDEWEB)

    Bonhomme, N [Nuclear Power International, Cedex (France); Py, J P [FRAMATOME, Cedex (France)

    1996-12-01

    In attempting to review how EPR is contemplated to meet requirements applicable to future nuclear power plants, the authors indicate where they see the markets and the corresponding unit sizes for the EPR which is a generic key factor for competitiveness. There are no reason in industrialized countries, other than USA (where the investment and amortizing practices under control by Public Utility Commission are quite particular), not to build future plants in the 1000 to 1500 MWe range. Standardization, which has been actively applied all along the French program and for the Konvoi plants, does not prevent evolution and allows to concentrate large engineering effort in smooth realization of plants and achieve actual construction and commissioning without significant delays. In order to contribute to public trust renewal, a next generation of power reactors should be fundamentally less likely to incur serious accidents. To reach this goal the best of passive and active systems must be considered without forgetting that the most important source of knowledge is construction and operating experience. Criteria to assess passive systems investigated for possible implementation in the EPR, such as simplicity of design, impact on plant operation, safety and cost, are discussed. Examples of the principal passive systems investigated are described and reasons why they have been dropped after screening through the criteria are given. (author). 11 figs.

  3. Use of the Frank sequence in pulsed EPR

    DEFF Research Database (Denmark)

    Tseitlin, Mark; Quine, Richard W.; Eaton, Sandra S.

    2011-01-01

    The Frank polyphase sequence has been applied to pulsed EPR of triarylmethyl radicals at 256MHz (9.1mT magnetic field), using 256 phase pulses. In EPR, as in NMR, use of a Frank sequence of phase steps permits pulsed FID signal acquisition with very low power microwave/RF pulses (ca. 1.5m......W in the application reported here) relative to standard pulsed EPR. A 0.2mM aqueous solution of a triarylmethyl radical was studied using a 16mm diameter cross-loop resonator to isolate the EPR signal detection system from the incident pulses. Keyword: Correlation spectroscopy,Multi-pulse EPR,Low power pulses,NMR,EPR...

  4. Confirmation of a second EPR to be built at Penly

    International Nuclear Information System (INIS)

    Anon.

    2009-01-01

    The French government has made public its decision to launch the construction of a second EPR in France. This EPR is planned to be built on the Penly site (northern region of France). EDF will manage this project but other investors like GDF-Suez are invited to participate. The construction works are planned to begin in 2012 for a commissioning in 2017. This reactor will be the fifth EPR being built in the world. (A.C.)

  5. EPR study on gamma-irradiated fruits dehydrated via osmosis

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2007-06-15

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and {gamma}-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas {gamma}-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

  6. Two-dimensional 220 MHz Fourier transform EPR imaging

    International Nuclear Information System (INIS)

    Placidi, Giuseppe; Brivati, John A.; Alecci, Marcello; Testa, Luca; Sotgiu, Antonello

    1998-01-01

    In the last decade radiofrequency continuous-wave EPR spectrometers have been developed to detect and localize free radicals in vivo. Only recently, pulsed radiofrequency EPR spectrometers have been described for imaging applications with small samples. In the present work, we show the first two-dimensional image obtained at 220 MHz on a large phantom (40 ml) that simulates typical conditions of in vivo EPR imaging. This pulsed EPR apparatus has the potential to make the time required for three-dimensional imaging compatible with the biological half-life of normally used paramagnetic probes. (author)

  7. EPR study on gamma-irradiated fruits dehydrated via osmosis

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Aleksieva, K.

    2007-01-01

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples

  8. EPR study on gamma-irradiated fruits dehydrated via osmosis

    Science.gov (United States)

    Yordanov, N. D.; Aleksieva, K.

    2007-06-01

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit "sugar-like" EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

  9. A web-based database for EPR centers in semiconductors

    International Nuclear Information System (INIS)

    Umeda, T.; Hagiwara, S.; Katagiri, M.; Mizuochi, N.; Isoya, J.

    2006-01-01

    We develop a web-based database system for electron paramagnetic resonance (EPR) centers in semiconductors. This database is available to anyone at http://www.kc.tsukuba.ac.jp/div-media/epr/. It currently has more than 300 records of the spin-Hamiltonian parameters for major known EPR centers. One can upload own new records to the database or can use simulation tools powered by EPR-NMR(C). Here, we describe the features and objectives of this database, and mention some future plans

  10. EPR investigation of some gamma-irradiated medicines

    International Nuclear Information System (INIS)

    Aleksieva, Katerina; Yordanov, Nicola

    2016-01-01

    The results of EPR studies on three medical tablets – Galanthamine, Cytisine and Tribulus terrestris before and after gamma-irradiation are reported. Before irradiation Galanthamine and Cytisine tablets are EPR silent, whereas Tribulus terrestris show a broad singlet line with g factor 2.2084±0.002. The same spectrum is recorded after irradiation. After gamma-sterilization, however, Galanthamine and Cytisine tablets exhibit a typical EPR spectrum due to gamma induced free radicals in lactose used as an excipient. These stable free radicals can be used for identification of radiation processing for a long time after it. Key words: medical tablets, gamma-irradiation, EPR

  11. Final environmental assessment for vegetation control at VHF stations, microwave stations, electrical substations, and pole yards

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-13

    Southwestern Power Adm. operates very high frequency (VHF) and microwave radio stations, electrical substations, and pole yards for electric power transmission throughout AR, MO, and OK. Vegetation growth at the stations must be suppressed for safety of operation and personnel. Southwestern has been using a combination of mechanical/manual and herbicide control for this purpose; Federally- mandated reductions in staff and budgetary resources require Southwestern to evaluate all potentially efficient methods for vegetation control. Three alternatives were examined: no action, mechanical/manual control, and (proposed) a combination of mechanical/manual and herbicide control. Environmental impacts on air and water quality, wetlands, wildlife, endangered species, archaeological and other resources, farmland, human health, transportation, etc. were evaluated.

  12. Morphology and Structural Characterization of Carbon Nanowalls Grown via VHF-PECVD

    Science.gov (United States)

    Akmal Hasanudin, M.; Wahab, Y.; Ismail, A. K.; Zahid Jamal, Z. A.

    2018-03-01

    A 150 MHz very high frequency plasma enhanced chemical vapor deposition (150 MHz VHF-PECVD) system was utilized to fabricate two-dimensional carbon nanostructure from the mixture of methane and hydrogen. Morphology and structural properties of the grown nanostructure were investigated by FESEM imaging and Raman spectroscopy. Carbon nanowalls (CNW) with dense and wavy-like structure were successfully synthesized. The wavy-like morphology of CNW was found to be more distinct during growth at small electrode spacing and denser with increasing deposition time due to better flux of hydrocarbon radicals to the substrate and higher rate of reaction, respectively. Typical characteristics of CNW were observed from strong D band, narrow bandwidth of G band and single broad peak of 2D band of Raman spectra indicating the presence of disordered nanocrystalline graphite structure with high degree of graphitization.

  13. Graphene-based tunable non-foster circuit for VHF applications

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Jing; Nagarkoti, Deepak Singh; Rajab, Khalid Z.; Hao, Yang, E-mail: y.hao@qmul.ac.uk [School of Electronic Engineering and Computer Science, Queen Mary, University of London, London, E1 4NS (United Kingdom)

    2016-06-15

    This paper presents a negative impedance converter (NIC) based on graphene field effect transistors (GFETs) for VHF applications. The NIC is designed following Linvill’s open circuit stable (OCS) topology. The DC modelling parameters of GFET are extracted from a device measured by Meric et al. [IEEE Electron Devices Meeting, 23.2.1 (2010)] Estimated parasitics are also taken into account. Simulation results from Keysight Advanced Design System (ADS) show good NIC performance up to 200 MHz and the value of negative capacitance is directly proportional to the capacitive load. In addition, it has been shown that by varying the supply voltage the value of negative capacitance can also be tuned. The NIC stability has been tested up to 2 GHz (10 times the maximum operation frequency) using Nyquist stability criterion to ensure there are no oscillation issues.

  14. Development of a High-Brightness VHF Electron Source at LBNL

    International Nuclear Information System (INIS)

    Lidia, Steven M.; Sannibale, Fernando; Staples, John W.; Virostek, Steve P.; Wells, Russell P.

    2007-01-01

    Currently proposed ERL and high average power FEL projects require electron beam sources that can generate ∼1nC bunch charges at high repetition rates. Many proposed sources are based around either high voltage DC or microwave RF guns, each with its particular set of technological limits and system complications. We propose a novel solution that greatly diminishes high voltage breakdown issues while also decreasing peak RF power requirements in a warm copper device, and that has the benefit of mapping the rf oscillation period much more closely to the required beam repetition rate. We present the initial RF and mechanical design for a 750kV electron source and beam injection system utilizing a gun resonant in the VHF band. Beam dynamics simulations demonstrate excellent beam quality preservation and transport

  15. Graphene-based tunable non-foster circuit for VHF applications

    Directory of Open Access Journals (Sweden)

    Jing Tian

    2016-06-01

    Full Text Available This paper presents a negative impedance converter (NIC based on graphene field effect transistors (GFETs for VHF applications. The NIC is designed following Linvill’s open circuit stable (OCS topology. The DC modelling parameters of GFET are extracted from a device measured by Meric et al. [IEEE Electron Devices Meeting, 23.2.1 (2010] Estimated parasitics are also taken into account. Simulation results from Keysight Advanced Design System (ADS show good NIC performance up to 200 MHz and the value of negative capacitance is directly proportional to the capacitive load. In addition, it has been shown that by varying the supply voltage the value of negative capacitance can also be tuned. The NIC stability has been tested up to 2 GHz (10 times the maximum operation frequency using Nyquist stability criterion to ensure there are no oscillation issues.

  16. Locations of radical species in black pepper seeds investigated by CW EPR and 9GHz EPR imaging.

    Science.gov (United States)

    Nakagawa, Kouichi; Epel, Boris

    2014-10-15

    In this study, noninvasive 9GHz electron paramagnetic resonance (EPR)-imaging and continuous wave (CW) EPR were used to investigate the locations of paramagnetic species in black pepper seeds without further irradiation. First, lithium phthalocyanine (LiPC) phantom was used to examine 9GHz EPR imaging capabilities. The 9GHz EPR-imager easily resolved the LiPC samples at a distance of ∼2mm. Then, commercially available black pepper seeds were measured. We observed signatures from three different radical species, which were assigned to stable organic radicals, Fe(3+), and Mn(2+) complexes. In addition, no EPR spectral change in the seed was observed after it was submerged in distilled H2O for 1h. The EPR and spectral-spatial EPR imaging results suggested that the three paramagnetic species were mostly located at the seed surface. Fewer radicals were found inside the seed. We demonstrated that the CW EPR and 9GHz EPR imaging were useful for the determination of the spatial distribution of paramagnetic species in various seeds. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Partial Discharge Spectral Characterization in HF, VHF and UHF Bands Using Particle Swarm Optimization.

    Science.gov (United States)

    Robles, Guillermo; Fresno, José Manuel; Martínez-Tarifa, Juan Manuel; Ardila-Rey, Jorge Alfredo; Parrado-Hernández, Emilio

    2018-03-01

    The measurement of partial discharge (PD) signals in the radio frequency (RF) range has gained popularity among utilities and specialized monitoring companies in recent years. Unfortunately, in most of the occasions the data are hidden by noise and coupled interferences that hinder their interpretation and renders them useless especially in acquisition systems in the ultra high frequency (UHF) band where the signals of interest are weak. This paper is focused on a method that uses a selective spectral signal characterization to feature each signal, type of partial discharge or interferences/noise, with the power contained in the most representative frequency bands. The technique can be considered as a dimensionality reduction problem where all the energy information contained in the frequency components is condensed in a reduced number of UHF or high frequency (HF) and very high frequency (VHF) bands. In general, dimensionality reduction methods make the interpretation of results a difficult task because the inherent physical nature of the signal is lost in the process. The proposed selective spectral characterization is a preprocessing tool that facilitates further main processing. The starting point is a clustering of signals that could form the core of a PD monitoring system. Therefore, the dimensionality reduction technique should discover the best frequency bands to enhance the affinity between signals in the same cluster and the differences between signals in different clusters. This is done maximizing the minimum Mahalanobis distance between clusters using particle swarm optimization (PSO). The tool is tested with three sets of experimental signals to demonstrate its capabilities in separating noise and PDs with low signal-to-noise ratio and separating different types of partial discharges measured in the UHF and HF/VHF bands.

  18. Identification and dose assessment of irradiated cardamom and cloves by EPR spectrometry

    International Nuclear Information System (INIS)

    Beshir, W.B.

    2014-01-01

    The use of electron paramagnetic resonance spectroscopy to accurately distinguish irradiated from unirradiated cardamom and cloves and assesses the absorbed dose to radiation processed cardamom and cloves are examined. The results were successful for identifying both irradiated and unirradiated cardamom and cloves. Additive reirradiation of cardamom and cloves produces reproducible dose–response functions, which can be used to assess the initial dose by back-extrapolation. Third degree polynomial function was used to fit the EPR signal/dose curves. It was found that this 3rd degree polynomial function provides satisfactory results without correction of decay for free radicals. The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over a storage period of almost 8 months. The calculated G-value (The number of radicals per 100 eV of absorbed energy) for cardamom and cloves was found 0.07±0.01 and 0.055±0.01, respectively. - Highlights: • The EPR analysis of cardamom and cloves prove the sample has been irradiated or not. • Dose additive can be used for evaluation of the absorbed dose in cardamom and cloves. • The 3rd polynomial function can be used to fit the data and the estimated dose. • The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over 2 months

  19. Application of EPR retrospective dosimetry for large-scale accidental situation

    International Nuclear Information System (INIS)

    Skvortsov, V.G.; Ivannikov, A.I.; Stepanenko, V.F.; Tsyb, A.F.; Khamidova, L.G.; Kondrashov, A.E.; Tikunov, D.D.

    2000-01-01

    Above 3000 tooth enamel samples, collected at population of radioactive contaminated territories after Chernobyl accident, the Chernobyl liquidators, the retired military of high radiation risk and the population of control radiation free territories were investigated by EPR spectroscopy method in order to obtain accumulated individual exposure doses. Results of EPR spectra measurements are stored in data bank; enamel samples are also stored in order to provide the possibility to repeat the measurements in future. Statistical analysis of results has allowed to detect the contribution into EPR signal in tooth enamel due to the action of the natural background radiation, and the radioactive contamination of territory. In general, the average doses of external exposure of the population obtained with EPR spectroscopy of teeth enamel are consistent with results based on other methods of direct and retrospective dosimetry. Essential exceeding of the individual doses above the average level within the population groups was observed for some persons. That gave the possibility to detect the individuals with overexposure, which were included into groups for medical monitoring

  20. Development of compatibilized SBR and EPR nanocomposites containing dual filler system

    International Nuclear Information System (INIS)

    Rajasekar, R.; Nayak, G.C.; Malas, A.; Das, C.K.

    2012-01-01

    Highlights: ► Nanoclay is dispersed in non-polar rubbers by utilizing a polar compatibilizer. ► Effect of dual fillers [nanoclay and carbon black] on the rubber properties. ► Comparison of the results of single and dual filler containing rubber compounds. -- Abstract: The study described in this paper is an analysis of the role of a compatibilizer for dispersing organically modified nanoclay in styrene butadiene rubber (SBR) and ethylene propylene rubber (EPR) matrices. The normal mixing of non-polar rubbers and organically modified nanoclay may not lead to improved distribution of the nanofiller in the rubbery matrix. Hence, a polar rubber such as epoxidized natural rubber (ENR) can be used as a compatibilizer for dispersing nanoclay in the non-polar rubber matrices. ENR–organically modified nanoclay composites (EC) were prepared by solution mixing. The nanoclay used in this study is Cloisite 20A. The obtained ENR–nanoclay composites were incorporated in SBR and EPR matrices along with carbon black. The morphological studies proved the intercalation of nanoclay platelets in ENR and further incorporation of EC in SBR and EPR matrices leads to partial exfoliation of nanoclay platelets. A curing study demonstrated faster scorch time, cure time and increased maximum torque for the compatibilized SBR and EPR nanocomposites containing a dual filler system compared to the control. Dynamic mechanical thermal analysis showed increase in storage modulus for the SBR and EPR compounds containing dual fillers compared to rubber compounds containing pure and single filler. The same compounds show substantial improvement in mechanical properties. The tensile fractured surface of the rubber compounds containing single and dual filler observed by scanning electron microscopy, (SEM) showed highly rough and irregular fracture paths, which proved the physical interaction between filler and rubber.

  1. Contribution of Harold M. Swartz to In Vivo EPR and EPR Dosimetry.

    Science.gov (United States)

    Gallez, Bernard

    2016-12-01

    In 2015, we are celebrating half a century of research in the application of Electron Paramagnetic Resonance (EPR) as a biodosimetry tool to evaluate the dose received by irradiated people. During the EPR Biodose 2015 meeting, a special session was organized to acknowledge the pioneering contribution of Harold M. (Hal) Swartz in the field. The article summarizes his main contribution in physiology and medicine. Four emerging themes have been pursued continuously along his career since its beginning: (1) radiation biology; (2) oxygen and oxidation; (3) measuring physiology in vivo; and (4) application of these measurements in clinical medicine. The common feature among all these different subjects has been the use of magnetic resonance techniques, especially EPR. In this article, you will find an impressionist portrait of Hal Swartz with the description of the 'making of' this pioneer, a time-line perspective on his career with the creation of three National Institutes of Health-funded EPR centers, a topic-oriented perspective on his career with a description of his major contributions to Science, his role as a mentor and his influence on his academic children, his active role as founder of scientific societies and organizer of scientific meetings, and the well-deserved international recognition received so far. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Contribution of Harold M. Swartz to In Vivo EPR and EPR Dosimetry

    International Nuclear Information System (INIS)

    Gallez, Bernard

    2016-01-01

    In 2015, we are celebrating half a century of research in the application of Electron Paramagnetic Resonance (EPR) as a biodosimetry tool to evaluate the dose received by irradiated people. During the EPR Biodose 2015 meeting, a special session was organized to acknowledge the pioneering contribution of Harold M. (Hal) Swartz in the field. The article summarizes his main contribution in physiology and medicine. Four emerging themes have been pursued continuously along his career since its beginning: (1) radiation biology; (2) oxygen and oxidation; (3) measuring physiology in vivo; and (4) application of these measurements in clinical medicine. The common feature among all these different subjects has been the use of magnetic resonance techniques, especially EPR. In this article, you will find an impressionist portrait of Hal Swartz with the description of the 'making of' this pioneer, a time-line perspective on his career with the creation of three National Institutes of Health-funded EPR centers, a topic-oriented perspective on his career with a description of his major contributions to Science, his role as a mentor and his influence on his academic children, his active role as founder of scientific societies and organizer of scientific meetings, and the well-deserved international recognition received so far. (author)

  3. EPR: what has it taught us

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1985-05-01

    This symposium commemorating the fiftieth anniversary of the paper of Einstein, Podolsky, and Rosen is a fitting place to review what that work and its sequels have taught us. Prima facie, the EPR paper appears to have been exceedingly counter-productive for the following reasons: (1) The work was quickly rebutted by Bohr, and this rebuttal was apparently accepted by most workers in the field. (2) Scientists who adopted the position advocated by Bohr have produced, in the intervening fifty years, a marvelous body of useful theory, whereas those following the course suggested by EPR have produced nothing of any certified practical value. (3) It has been shown by Bell that the conclusion reached by EPR is incompatible with their assumptions. Chemists and physicists have recently begun to examine the behavior of quantum mechanical systems that are very small, yet large enough to influence their environment in ways that appreciably modify their own behavior, vis-a-vis the behavior they would have if isolated. Because these systems are neither small enough to be treated as isolated (or as residing in a classically described environment) between preparation and detection, nor large enough to be treated classically, they do not conform to the format demanded by the Copenhagen interpretation. Indeed, the behavior of these systems depends on ontological considerations that were irrelevant in the situations covered by the Copenhagen interpretation, and that were systematically ignored in that interpretation. Scientists now face the task of enlarging the scope of quantum theory to cover these new situations, and comparing the empirical consequences of various ontological assumptions. 17 refs

  4. EPR spin trapping of protein radicals

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Hawkins, Clare Louise

    2004-01-01

    Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress...... tumbling radicals are often broad and relatively poor in distinctive features, a number of techniques have been developed that allow a wealth of information to be obtained about the nature, site, and reactions of such radicals. This article summarizes recent developments in this area and reviews selected...... examples of radical formation on proteins....

  5. E-PR technologies in political party activities

    OpenAIRE

    Tereshchuk Vitaliy Ivanovych

    2016-01-01

    The article discusses the role of the Internet as an important communicative tool in the field of political PR. The article reviews the characteristics of PR-activities on the Internet and the features of e-PR in the political sphere. Particular attention is paid to the system of political party’s e-PR tools.

  6. PropeR: a multi disciplinary EPR system

    NARCIS (Netherlands)

    van der Linden, Helma; Boers, Gerrit; Tange, Huibert; Talmon, Jan; Hasman, Arie

    2003-01-01

    This article describes the architecture of an EPR system developed for the PropeR project. This EPR system not only aims at supporting home care of stroke patients, but is also designed in such a way that it can be ported to other medical services without much effort. We will briefly describe the

  7. EPR study on tomatoes before and after gamma-irradiation

    International Nuclear Information System (INIS)

    Aleksieva, K.; Georgieva, L.; Tzvetkova, E.; Yordanov, N.D.

    2009-01-01

    The results from the EPR studies on fresh, air-dried and lyophilized tomato samples before and after gamma-irradiation are reported. Before irradiation fresh and air-dried tomatoes exhibit one singlet EPR line characterized with common g-factor of 2.0048±0.0005, whereas freeze-dried tomato does not show any EPR spectrum. After irradiation, a typical 'cellulose-like' triplet EPR spectrum appears in all samples, attributed to cellulose free radicals, generated by gamma-irradiation. It consists of intense central line with g=2.0048±0.0005 and two weak satellite lines separated ca. 3 mT left and right of it. In air-dried and lyophilized tomatoes the 'cellulose-like' EPR spectrum is superimposed by an additional partly resolved carbohydrate spectrum. Fading measurements of the radiation-induced EPR signals indicate that the intensity of the EPR spectra of air-dried and freeze-dried tomato are reduced to about 50% after 50 days, whereas those of fresh irradiated tomatoes kept at 4 o C fade completely in 15 days. The reported results unambiguously show that the presence of two satellite lines in the EPR 'cellulose-like' spectra of tomato samples can be used for identification of radiation processing.

  8. EPR and NMR spectroscopy on spin-labeled proteins

    NARCIS (Netherlands)

    Finiguerra, Michelina Giuseppina

    2011-01-01

    Spin labeling and electron paramagnetic resonance (EPR) have been employed to study structure and dynamics of proteins. The surface polarity of four single cysteine mutants of the Zn-azurin in frozen solution were studied using 275 GHz EPR (J-band), with the advantage compared to 9 GHz (X-band) and

  9. Case Studies in e-RPL and e-PR

    Science.gov (United States)

    Cameron, Roslyn; Miller, Allison

    2014-01-01

    The use of ePortfolios for recognition of prior learning (e-RPL) and for professional recognition (e-PR) is slowly gaining in popularity in the VET sector however their use is sporadic across educational sectors, disciplines, educational institutions and professions. Added to this is an array of purposes and types of e-RPL and e-PR models and…

  10. The Employment Precariousness Scale (EPRES): psychometric properties of a new tool for epidemiological studies among waged and salaried workers.

    Science.gov (United States)

    Vives, Alejandra; Amable, Marcelo; Ferrer, Montserrat; Moncada, Salvador; Llorens, Clara; Muntaner, Carles; Benavides, Fernando G; Benach, Joan

    2010-08-01

    Despite the fact that labour market flexibility has resulted in an expansion of precarious employment in industrialised countries, to date there is limited empirical evidence concerning its health consequences. The Employment Precariousness Scale (EPRES) is a newly developed, theory-based, multidimensional questionnaire specifically devised for epidemiological studies among waged and salaried workers. To assess the acceptability, reliability and construct validity of EPRES in a sample of waged and salaried workers in Spain. A sample of 6968 temporary and permanent workers from a population-based survey carried out in 2004-2005 was analysed. The survey questionnaire was interviewer administered and included the six EPRES subscales, and measures of the psychosocial work environment (COPSOQ ISTAS21) and perceived general and mental health (SF-36). A high response rate to all EPRES items indicated good acceptability; Cronbach's alpha coefficients, over 0.70 for all subscales and the global score, demonstrated good internal consistency reliability; exploratory factor analysis using principal axis analysis and varimax rotation confirmed the six-subscale structure and the theoretical allocation of all items. Patterns across known groups and correlation coefficients with psychosocial work environment measures and perceived health demonstrated the expected relations, providing evidence of construct validity. Our results provide evidence in support of the psychometric properties of EPRES, which appears to be a promising tool for the measurement of employment precariousness in public health research.

  11. Investigation of anisotropy in EPR spectra of radiation defects in irradiated beryllium ceramics

    International Nuclear Information System (INIS)

    Polyakov, A.I.; Ryabikin, Yu.A.; Zashkvara, O. V.; Bitenbaev, M.I.; Petukhov, Yu. V.

    2004-01-01

    Full text: In this work results of analysis of anisotropy and hyperfine structure in EPR spectra of paramagnetic defects in irradiated samples of beryllium ceramics are presented. To explain peculiarities in a shape and parameters of the EPR spectrum hyperfine structure in beryllium ceramics, we have analyzed several versions of model representations for the radiation-induced paramagnetic defects uniformly distributed in a sample as well as for cluster defects which hyperfine structure is determined by interactions between electrons and nuclei of impurity atoms (S=1/2) and which are characterized by anisotropy in the g factors. Calculations of a shape of the uniformly widened EPR spectra are carried out by the model of random interactions between electron spins. The EPR spectra, widened at the expense of anisotropy in the g factors, are calculated by the following equation: g(Δ)=[2(ω-ω 0 )+α] -1/2 , where ω 0 =γH 0 , α is the quantify proportional to the anisotropy shift. To describe wings of spectral lines, where the equation doesn't work, we use the Gaussian function. To determine the frequency of precession of electron spins packages with local concentration N loc , the following expression is used: ω=ω 0 +1/2α(3cos 2 θ-1), where θ is an angle between the symmetry axis and the direction of the external magnetic field. It is shown that the best agreement between the calculated and experimental EPR spectra is observed with the following computational model: paramagnetic radiation defects are distributed uniformly over a ceramics sample, and the g factors of its EPR spectra have the anisotropy typical for dipole-dipole interaction in powder samples. By results of the data we obtained, it's clear that in future we'll need in more detailed information than that published in scientific journals about formation of the paramagnetic defect EPR spectra structure in beryllium oxides and ceramics at the expense of resonance line hyperfine splitting on atoms of

  12. Investigation of anisotropy in EPR spectra of radiation defects in irradiated beryllium ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, A I; Ryabikin, Yu A; Zashkvara, O V; Bitenbaev, M I; Petukhov, Yu V [Inst. of Physics and Technology, Almaty (Kazakhstan)

    2004-07-01

    Full text: In this work results of analysis of anisotropy and hyperfine structure in EPR spectra of paramagnetic defects in irradiated samples of beryllium ceramics are presented. To explain peculiarities in a shape and parameters of the EPR spectrum hyperfine structure in beryllium ceramics, we have analyzed several versions of model representations for the radiation-induced paramagnetic defects uniformly distributed in a sample as well as for cluster defects which hyperfine structure is determined by interactions between electrons and nuclei of impurity atoms (S=1/2) and which are characterized by anisotropy in the g factors. Calculations of a shape of the uniformly widened EPR spectra are carried out by the model of random interactions between electron spins. The EPR spectra, widened at the expense of anisotropy in the g factors, are calculated by the following equation: g({delta})=[2({omega}-{omega}{sub 0})+{alpha}]{sup -1/2}, where {omega}{sub 0}={gamma}H{sub 0}, {alpha} is the quantify proportional to the anisotropy shift. To describe wings of spectral lines, where the equation doesn't work, we use the Gaussian function. To determine the frequency of precession of electron spins packages with local concentration N{sub loc}, the following expression is used: {omega}={omega}{sub 0}+1/2{alpha}(3cos{sup 2}{theta}-1), where {theta} is an angle between the symmetry axis and the direction of the external magnetic field. It is shown that the best agreement between the calculated and experimental EPR spectra is observed with the following computational model: paramagnetic radiation defects are distributed uniformly over a ceramics sample, and the g factors of its EPR spectra have the anisotropy typical for dipole-dipole interaction in powder samples. By results of the data we obtained, it's clear that in future we'll need in more detailed information than that published in scientific journals about formation of the paramagnetic defect EPR spectra structure in

  13. Properties of the ammonium tartrate/EPR dosimeter

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    2004-01-01

    The EPR response of γ-irradiated ammonium tartrate on the absorbed dose of γ-rays up to 22 kGy as well as the changes in the shape of the EPR spectrum upon applied modulation amplitude and microwave power are reported. Also the possibility to use ammonium tartrate together with Mn 2+ magnetically diluted in MgO as an internal reference material is evaluated. The influence of the microwave power and the modulation amplitude on their dose response is investigated. The results show that the radiation-induced EPR spectrum of ammonium tartrate, obtained at a low microwave power is complex consisting several patterns and is more easily saturated than the Mn 2+ EPR spectrum. In this case the following settings of the EPR parameters are recommended: H mod ≤0.05 mT and 10≤P MW ≤13 mW. Using these parameters the dosimeters can be considered for use in intercomparisons

  14. On the annealing of the EPR dislocation signal in silicon

    International Nuclear Information System (INIS)

    Zolotukhin, M.N.; Kveder, V.V.; Osip'yan, Yu.A.

    1981-01-01

    The annealing kinetics of the (EPR) dislocation signal (D-centers) in silicon is studied. The disappearance of the dislocation EPR signal as a result of annealing is ascribed to rearrangement of the nuclei of the partial dislocations accompanied by pairwise ''closing'' of the broken bonds in the S=0 state. The height of the energy barrier for the rearrangement process is approximately 2 eV. A residual ''nonannealing'' EPR signal is observed in strongly deformed silicon crystals. It resembles an isotropic line with a width approximately 7.5 Oe and a g-factor approximately 2.006. It is suggested that the respective EPR centers (O-centers) are similar to the EPR centers in amorphic silicon [ru

  15. Selective saturation method for EPR dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Ignatiev, E.A.; Romanyukha, A.A.; Koshta, A.A.; Wieser, A.

    1996-01-01

    The method of selective saturation is based on the difference in the microwave (mw) power dependence of the background and radiation induced EPR components of the tooth enamel spectrum. The subtraction of the EPR spectrum recorded at low mw power from that recorded at higher mw power provides a considerable reduction of the background component in the spectrum. The resolution of the EPR spectrum could be improved 10-fold, however simultaneously the signal-to-noise ratio was found to be reduced twice. A detailed comparative study of reference samples with known absorbed doses was performed to demonstrate the advantage of the method. The application of the selective saturation method for EPR dosimetry with tooth enamel reduced the lower limit of EPR dosimetry to about 100 mGy. (author)

  16. Limits in EPR dosimetry for irradiated dried fruits discrimination

    International Nuclear Information System (INIS)

    Brasoveanu, Mirela M. E-mirela@alpha.infim.ro; Nemtanu, R.; Minea, R.; Grecu, V.V.

    2003-01-01

    Irradiation of food induces free radical species. EPR dosimetry in irradiated goods puts in evidence if these radicals are stable in environmental condition. Irradiation of dried fruits has been carried out. Their behaviour under irradiation was investigated and correlation between EPR signal and irradiation dose was determined. Electrons of 6 MeV (mean energy) and doses up to 10 kGy were used. EPR spectra were recorded with a Jeol spectrometer, JES-ME-3X tip, with a 100 kHz modulation. The dried fruits can be separated into categories depending on the EPR signal intensity. Strong signals are observed in those fruits in which possible crystalline-like phases exist. As the amount of crystallized sugar decreases, the EPR signals become weaker. Dependencies on irradiation dose give a linear correlation below 10 kGy. The spectra are compared to irradiated sugar and differences and similarities are discussed. (authors)

  17. Costing the EPR Project Using the Real Options Method

    International Nuclear Information System (INIS)

    Epaulard, Anne; Gallon, Stephane

    2001-01-01

    Real options theory makes it possible to cost investments which offer flexibility but whose returns are uncertain, such as the construction in 2000 of an EPR prototype; this prototype will enable the European pressurised-water reactor (EPR) to be used to renew EDF's nuclear power stations in 2020 (flexibility) but its economic worth will then depend on the cost of the competing gas-fired power plants (uncertain return). Options theory shows that investing in EPR technology in 2000 provides sufficient flexibility in 2020 to be considered cost-effective, even though use of EPRs is unlikely by that date. The investment made in 2000 to develop EPR technology therefore actually plays the part of an option or, in other words, insurance (against the risk of high gas prices)

  18. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    Science.gov (United States)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  19. Deploying the advanced U.S. EPR

    International Nuclear Information System (INIS)

    Hagan, C.

    2007-01-01

    As electricity demand, clean air concerns and energy prices increase in the U.S., interest in new nuclear reactors is also on the rise. These factors - along with decades of outstanding performance of the nation's existing nuclear fleet - have contributed to a favorable market for new nuclear power in the U.S. Although no U.S. company has declared it actually will buy and build new reactors, many have actively expressed their interest through investment and regulatory interaction. The timing is also right for new reactors in terms of public perception, government policy and acceptance of the investment community. Amid this environment, the U.S. commercial power industry recently has begun pursuing new nuclear generation in earnest. AREVA, whose ongoing global market analyses indicated the need for additional baseload nuclear generation in the U.S., chose to license its EPR design to meet that need. This article will discuss the American market landscape for new nuclear and how AREVA is approaching it, present an overview of the company's U.S. EPR technology, and provide an update on the regulatory status of the design and deployment schedule. (orig.)

  20. Radiation protection on EPR: comparative approach of the French and Finnish regulatory reviewing process and optimization at the design phase

    International Nuclear Information System (INIS)

    Arial, E.; Couasnon, O.; Latil-querrec, N.; Evrard, J.M.; Herviou, K.; Riihiluoma, V.; Beneteau, Y.; Foret, J.L.

    2010-01-01

    Taking the opportunity to evaluate the preliminary safety report of the French EPR reactor built in Flamanville, the IRSN proposes to assess the history of EPR, from the decision to implement studies in the 90's to the French and German cooperation, and finally to the construction of a unit in Finland and in France, and to make a synthesis of the assessment of radiation protection arrangements. This assessment presents the dose targets (calculated reference doses) planned by the nuclear operators in the design phase as well as the global radiation protection optimization process and a comparison of French and Finnish analyses. In France, for example, EDF performed a detailed optimization analysis of selected tasks known to have a major contribution to the annual average collective dose (thermal insulation, logistics, valve maintenance, opening/closing of the vessel, preparation and checks of steam generators, on-site spent fuel management, and waste management). The optimization process is based (in France) on an iterative method. A comparison between the EPR collective dose target and doses received in other pressurized water reactors that are close to the EPR design (Konvoi of German design, French existing units, etc.) is also presented. This synthesis was carried out by the IRSN, the expert body of the French nuclear safety authority, in association with Electricite de France (EDF), the French operator, and the authority for nuclear safety in Finland (STUK). It summarizes more than 15 years of studies and partnership, focusing on radiation protection, in the design phase of the EPR. (authors)

  1. Meteor head echo altitude distributions and the height cutoff effect studied with the EISCAT HPLA UHF and VHF radars

    Directory of Open Access Journals (Sweden)

    A. Westman

    2004-04-01

    Full Text Available Meteor head echo altitude distributions have been derived from data collected with the EISCAT VHF (224MHz and UHF (930MHz high-power, large-aperture (HPLA radars. At the high-altitude end, the distributions cut off abruptly in a manner reminiscent of the trail echo height ceiling effect observed with classical meteor radars. The target dimensions are shown to be much smaller than both the VHF and the UHF probing wavelengths, but the cutoff heights for the two systems are still clearly different, the VHF cutoff being located several km above the UHF one. A single-collision meteor-atmosphere interaction model is used to demonstrate that meteors in the (1.3–7.2µg mass range will ionise such that critical electron density at 224MHz is first reached at or around the VHF cutoff altitude and critical density at 930MHz will be reached at the UHF cutoff altitude. The observed seasonal variation in the cutoff altitudes is shown to be a function of the seasonal variation of atmospheric density with altitude. Assuming that the electron density required for detection is in the order of the critical density, the abrupt altitude cutoffs can be explained as a consequence of the micrometeoroid joint size-speed distribution dropping off so fast at the large-mass, high-velocity end that above a certain altitude the number of detectable events becomes vanishingly small. Conversely, meteors at the low-mass end of the distribution will be gradually retarded such that the ionisation they generate never reaches critical density. These particles will remain unobservable.Key words. Radio science (instruments and techniques – Interplatery physics (interplanetary dust – General or miscellaneous (new fields

  2. Broadband VHF Interferometer Observations of an Energetic In-cloud Pulse (EIP)

    Science.gov (United States)

    Tilles, J.; Krehbiel, P. R.; Stanley, M. A.; Rison, W.; Lyu, F.; Cummer, S.; Liu, N.; Dwyer, J. R.; Brown, R. G.; Wilson, J. G.

    2017-12-01

    Energetic in-cloud pulses (EIPs) are a little-known in-cloud subprocess of lightning. While they may be best identified by their large peak current (>200 kA) [Lyu et al., Geophys. Res. Lett., 42, 2015], they differ from narrow bipolar events (NBEs) - another type of in-cloud, high peak-current process - in that the sferic of an EIP lasts an order of magnitude longer ( ˜100 us) than that of a typical NBE ( ˜10 us). To further differentiate them from NBEs, EIPs are generally embedded within other electrical activity, whereas NBEs are known to primarily occur in isolation or as a lightning-initiating event [Smith et al., J. Geophys. Res., 104, D4, 4189-4212, 1999; Rison et al., Nat. Commun., 7, 10721, 2016]. Moreover, EIPs may have an intrinsic connection with the production of terrestrial gamma ray flashes (TGFs) [Cummer et al., Geophys. Res. Lett., 41, 8586-8593, 2014].Here we present coincident broadband VHF interferometer (INTF) observations and electric and magnetic field waveforms of an EIP with an associated NLDN peak current of 247 kA. The EIP occurs nearly 4 ms into a normal-polarity intracloud flash as part of the upward extension of the negative-polarity lightning leader. For this reason, we suspect that EIPs are a more energetic version of initial breakdown pulses (IBPs), which accompany the development of negative stepped leaders [e.g. Marshall et al., J. Geophys. Res. Atmos., 119, 445-460, 2014]. In addition, we show similarities with NBE-producing fast breakdown [Rison et al., 2016; Tilles et al., AE12A-03, AGU Fall Meeting, 2016], in that the breakdown accompanying the EIP propagates over a similar vertical extent ( ˜0.5-1 km) and with similar propagation speed ( ˜3×107 m/s). The INTF was developed by New Mexico Tech and has been deployed at Kennedy Space Center since July 2016. It employed three 100-m baselines in 2016, has a bandwidth of 14-88 MHz and samples at 180 MS/s with 16-bit resolution. A synchronously digitized fast antenna (FA), with

  3. Review of the correlation between results of cytogenetic dosimetry from blood lymphocytes and EPR dosimetry from tooth enamel for victims of radiation accidents

    International Nuclear Information System (INIS)

    Khvostunov, I.K.; Ivannikov, A.I.; Skvortsov, V.G.; Golub, E.V.; Nugis, V. Yu.

    2015-01-01

    The goal of this study was to compare dose estimates from electron paramagnetic resonance (EPR) dosimetry with teeth and cytogenetic dosimetry with blood lymphocytes for 30 victims of radiation accidents. The whole-body exposures estimated by tooth enamel EPR dosimetry were ranging from 0.01 to 9.3 Gy. Study group comprised victims exposed to acute and prolonged irradiation at high and low dose rate in different accidents. Blood samples were taken from each of them for cytogenetic analysis. Aberrations were scored and analysed according to International Atomic Energy Agency (IAEA) guidelines for conventional and FISH analysis. Tooth samples were collected in dental clinics after they had been extracted during ordinary practice. EPR dosimetry was performed according to the IAEA protocol. EPR dosimetry showed good correlation with dosimetry based on chromosomal analysis. All estimations of cytogenetic dose below detection limit coincide with EPR dose estimates within the ranges of uncertainty. The differences between cytogenetic and EPR assays may occur in a case of previous unaccounted exposure, non-homogeneous irradiation and due to contribution to absorbed dose from neutron irradiation. (authors)

  4. EPR design features to mitigate severe accident challenges

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Fischer, M.; Bittermann, D.

    2005-01-01

    The EPR, an evolutionary pressurized water reactor (PWR), is a 4300-4500 MWth that incorporates proven technology within an optimized configuration to enhance safety. EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product. Commercial EPR units are currently being built in Finland at the Olkiluoto site, and planned for France at the Flamanville site. In recent months, Framatome ANP announced their intention to market the EPR units to China in response to a request for vendor bids as well as their intent to pursue design certification in the United States under 10CFR52. The EPR safety philosophy is based on a deterministic consideration of defense-in-depth complemented by probabilistic analyses. Not only is the EPR designed to prevent and mitigate design basis accidents (DBAs), it employs an extra level of safety associated with severe accident response. Therefore, as a design objective, features are included to ensure that radiological consequences are limited such that the need for stringent counter measures, such as evacuation and relocation of the nearby population, can be reasonably excluded. This paper discusses some of the innovative features of the EPR to address severe accident challenges. (author)

  5. The EPR - technology for the 3rd Millennium

    International Nuclear Information System (INIS)

    Bernstrauch, O.

    2000-01-01

    The Basic Design of the European Pressurized Water Reactor (EPR) was completed 1997 , the Basic Design Optimization Phase 1998 and the Detailed Design Phase will start in the near future. With these milestones, a new generation of PWRs is moving forward. Most of all, this is another story of a successful Franco-German cooperation. It is a rundown of the history of the EPR, before a decision is made to launch the lead-unit construction. The EPR project was launched in 1992 by Nuclear Power International (NPI), a joint company of FRAMATOME and Siemens KWU, supported by EDF and nine German electric utilities. Each step of the development of the EPR was harmonized with the Nuclear Safety Authorities both in France and Germany to reach an early approval. The EPR integrates the latest technological advances, especially in safety and operational aspects and comprises more than 30 years operating experience. Thus, the EPR combines the qualities of its predecessors, the French N4 and the German Konvoi. Presently, Siemens KWU and FRAMATOME are preparing the detailed design phase and the following construction and commissioning phase. The decision to build an EPR is not yet made either by the German electric utilities or by EdF, but it will be expected within the next months as a strong statement to follow the nuclear way and to ensure the know-how transfer. (author)

  6. Identification of gamma-irradiated fruit juices by EPR spectroscopy

    Science.gov (United States)

    Aleksieva, K. I.; Dimov, K. G.; Yordanov, N. D.

    2014-10-01

    The results of electron paramagnetic resonance (EPR) study on commercially available juices from various fruits and different fruit contents: 25%, 40%, 50%, and 100%, homemade juices, nectars and concentrated fruit syrups, before and after gamma-irradiation are reported. In order to remove water from non- and irradiated samples all juices and nectars were filtered; the solid residue was washed with alcohol and dried at room temperature. Only concentrated fruit syrups were dried for 60 min at 40 °C in a standard laboratory oven. All samples under study show a singlet EPR line with g=2.0025 before irradiation with exception of concentrated fruit syrups, which are EPR silent. Irradiation of juice samples gives rise to complex EPR spectra which gradually transferred to "cellulose-like" EPR spectrum from 25% to 100% fruit content. Concentrated fruit syrups show typical "sugar-like" spectra due to added saccharides. All EPR spectra are characteristic and can prove radiation treatment. The fading kinetics of radiation-induced EPR signals were studied for a period of 60 days after irradiation.

  7. A Hash Based Remote User Authentication and Authenticated Key Agreement Scheme for the Integrated EPR Information System.

    Science.gov (United States)

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi; Wang, Chun-Cheng

    2015-11-01

    To protect patient privacy and ensure authorized access to remote medical services, many remote user authentication schemes for the integrated electronic patient record (EPR) information system have been proposed in the literature. In a recent paper, Das proposed a hash based remote user authentication scheme using passwords and smart cards for the integrated EPR information system, and claimed that the proposed scheme could resist various passive and active attacks. However, in this paper, we found that Das's authentication scheme is still vulnerable to modification and user duplication attacks. Thereafter we propose a secure and efficient authentication scheme for the integrated EPR information system based on lightweight hash function and bitwise exclusive-or (XOR) operations. The security proof and performance analysis show our new scheme is well-suited to adoption in remote medical healthcare services.

  8. Demonstration through EPR tests of the sensitivity of austeno-ferritic steels to intergranular corrosion and stress corrosion cracking

    International Nuclear Information System (INIS)

    Lopez, Nathalie

    1997-01-01

    Duplex stainless steels can be sensitised to intergranular corrosion and stress corrosion cracking (SCC) under some conditions (heat treatments, welding). The aim of this work is to contribute to the validation of the EPR (Electrochemical Potentiodynamic Reactivation) test in order to determine conditions for normalisation. This method, based on the dissolution of chromium depleted areas due to precipitation of σ-phase, provides a degree of sensitisation to intergranular corrosion. The test is broaden considering the mechanical stress by the way of slow strain rate tests, performed in chloride magnesium and in a solution similar to the EPR solution. A metallurgical study puts on the precipitates and the structural modifications due to welding and heat treatments, in order to make a critical analysis of the EPR test. (author) [fr

  9. EPR study of interactions in the MoOCl3 - diethyl dithiophosphate - diethylamine system

    International Nuclear Information System (INIS)

    Larin, G.M.; Minin, V.V.

    2004-01-01

    By the method of EPR in MoOCl 3 -DDFH-DEta system when reagents ration is 1:1:>3 formation of a new molybdenum(V) imidocomplex in situ solution is detected. Composition and structure of a new molybdenum(V) imidocomplex - composition is MoNRCl(DDF) 3 (DDFH), coordination number is 7, structure is pentagonal bipyramid - are determined using analysis of additional superfine structure from atoms of ligands forming coordination sphere of molybdenum(V) imidocomplex [ru

  10. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR.

    Science.gov (United States)

    Varkey, Jobin; Langen, Ralf

    2017-07-01

    The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single

  11. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR

    Science.gov (United States)

    Varkey, Jobin; Langen, Ralf

    2017-07-01

    The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single

  12. Einstein and the Quantum: The Secret Life of EPR

    Science.gov (United States)

    Fine, Arthur

    2006-05-01

    Locality, separation and entanglement -- 1930s style. Starting with Solvay 1927, we'll explore the background to the 1935 paper by Einstein, Podolsky and Rosen: how it was composed, the actual argument and principles used, and how the paper was received by Schroedinger, and others. We'll also look at Bohr's response: the extent to which Bohr connects with what Einstein was after in EPR and the extent to which EPR marks a shift in Bohr's thinking about the quantum theory. Time permitting, we will contrast EPR with Bell's theorem.

  13. EPR trademark project delivery. The value of experience

    International Nuclear Information System (INIS)

    Leverenz, Ruediger

    2013-01-01

    We are building the EPR trademark reactor fleet. Together. With four EPR trademark projects under construction in the world, AREVA has unrivalled experience in the delivery of large-scale nuclear projects, including more than a thousand lessons learned captured from Olkiluoto 3 and Flamanville 3 projects. This book of knowledge as well as the return of experience of AREVA's and EDF's teams are now being fully leveraged on ongoing projects, especially on Flamanville 3 and Taishan, and will be incorporated in all future EPR TM projects.

  14. EPR TOOTH DOSIMETRY OF SNTS AREA INHABITANTS.

    Science.gov (United States)

    Sholom, Sergey; Desrosiers, Marc; Bouville, André; Luckyanov, Nicholas; Chumak, Vadim; Simon, Steven L

    2007-07-01

    The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed "accident doses", were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine[ settlements were in the range from a few tens of mGy to approximately 100 mGy.

  15. EPR tooth dosimetry of SNTS area inhabitants

    Energy Technology Data Exchange (ETDEWEB)

    Sholom, Sergey [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Desrosiers, Marc [Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Bouville, Andre; Luckyanov, Nicholas [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States); Chumak, Vadim [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Simon, Steven L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States)], E-mail: ssimon@mail.nih.gov

    2007-07-15

    The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed 'accident doses', were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine settlements were in the range from a few tens of mGy to approximately 100 mGy.

  16. Radiation protection issues for EPR reactor

    International Nuclear Information System (INIS)

    Miniere, D.; Le Guen, B.; Beneteau, Y.; Le Guen, B.

    2008-01-01

    As part of the EPR (European Pressurized Reactor) project being deployed at Flamanville, EDF has pro actively made the decision to focus on radiation protection Radiation Protection aspects right from the start of the design phase, as it has done with nuclear safety. The approach adopted for managing Radiation Protection-significant activities has been to include all involved stakeholders - designers, licensee and contractor companies - in the three successive phases, starting with a survey among workers and designers, followed by a proposal review, and finally ending with the decision-making phase entrusted to an ALARA committee. The Radiation Protection target set by EDF for this new reactor is to engage in an effort of continuous improvement and optimisation, through benchmarking with the best performing plants of the fleet. The collective dose target is currently set at 0.35 Man Sv/year per unit. In addition to other aspects, efforts will focus on shortening the duration of the highest-dose jobs, with a new challenge being set for work performed in the reactor building during normal operations, the aim being to improve plant availability. The plan is for work to be performed 7 days prior to shutting down the reactor and 3 days afterwards, in order to make logistical arrangements for forthcoming jobs. Without this reduction, the estimated drop is currently 4.5% of annual dose. For this purpose, two areas have been set up in the E.P.R.'s reactor building: one no-go area for containing leaks from the primary circuit, and one accessible area for normal operations, separated from the no-go area by purpose-built ventilation equipment and facilities. To offer protection against radioactive flux (neutrons and high energy), Radiation Protection studies have resulted in the installation of a concrete floor and of nuclear shielding at the outlets of primary circuit pipes. Steam generator bunkers and pumps have also been reinforced. All these measures will ensure that the

  17. EPR by AREVA. An evolutionary reactor

    International Nuclear Information System (INIS)

    Horstmann, Marion

    2010-01-01

    The EPR development goals are as follows: 1. Evolutionary design to fully capitalize on the design, construction and operating experience based on the 86 AREVA's PWR operating worldwide; 2. Enhanced Safety compared to operating PWRs: reduce core damage frequency (CDF), accommodate severe accidents with no long-term population effect, Withstand large airplane crash (APC); 3. High availability; 4. Simplified operation and maintenance; and 5. Generation cost at least 10 % lower than 1500 MWe series in operation.The design builds on the achievements of the N4 and Konvoi reactors. The main plant data are tabulated. The PWR structure is shown as an example of the stepwise improvement. Focus of the presentation is on the construction techniques, supply chain, and project delivery. (P.A.)

  18. EPR's energy conversion system. Alstom's solutions

    International Nuclear Information System (INIS)

    Ledermann, P.

    2009-01-01

    ARABELLE steam turbines have been developed by Alstom to be used as the energy conversion system of light water reactors with high output power like the N4 PWR and the EPR. ARABELLE turbines cumulate 200.000 hours of service with a reliability ratio of 99.97 per cent. This series of slides presents the main features of the turbine including: the use of the simple flux, the very large shape of low pressure blades, the technology of welded rotors. The other main equipment like the alternator, the condenser, the moisture separator-reheaters, the circulating pumps that Alstom integrates in the energy conversion system have benefited with technological improvements that are also presented. (A.C.)

  19. EPR design tools. Integrated data processing tools

    International Nuclear Information System (INIS)

    Kern, R.

    1997-01-01

    In all technical areas, planning and design have been supported by electronic data processing for many years. New data processing tools had to be developed for the European Pressurized Water Reactor (EPR). The work to be performed was split between KWU and Framatome and laid down in the Basic Design contract. The entire plant was reduced to a logical data structure; the circuit diagrams and flowsheets of the systems were drafted, the central data pool was established, the outlines of building structures were defined, the layout of plant components was planned, and the electrical systems were documented. Also building construction engineering was supported by data processing. The tasks laid down in the Basic Design were completed as so-called milestones. Additional data processing tools also based on the central data pool are required for the phases following after the Basic Design phase, i.e Basic Design Optimization; Detailed Design; Management; Construction, and Commissioning. (orig.) [de

  20. EPR of CU+2:Mb single crystal

    International Nuclear Information System (INIS)

    Nascimento, O.R.; Ribeiro, S.C.; Bemski, G.

    1976-01-01

    Copper introduced into met-myoglobin crystals occupies various sites as indicated by EPR parameters. CU 2+ (A) is probably liganded to histidine A10, lysine A14 and asparagine GH4 (Banaszak, 1965) and shows super-hyperfine interaction with a single (imidazole) nitrogen. Cu 2+ (B) and Cu 2+ (C) correspond to other anisotropic sites described with lesser details. Cu 2+ (A) exhibits a transition to an isotropic form with a transition temperature of 40.5 0 C. This transition is indicative of a conformational change in myoglobin and could correspond to a motion of A helix away from the GH section. The transition temperature is 7 0 C higher than the previously reported (Atanasov, 1971) one for myoglobin in solution

  1. EPR paradox, quantum nonlocality and physical reality

    International Nuclear Information System (INIS)

    Kupczynski, M

    2016-01-01

    Eighty years ago Einstein, Podolsky and Rosen demonstrated that instantaneous reduction of wave function, believed to describe completely a pair of entangled physical systems, led to EPR paradox. The paradox disappears in statistical interpretation of quantum mechanics (QM) according to which a wave function describes only an ensemble of identically prepared physical systems. QM predicts strong correlations between outcomes of measurements performed on different members of EPR pairs in far-away locations. Searching for an intuitive explanation of these correlations John Bell analysed so called local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of QM and by experimental data. Several different local models were constructed and inequalities proven. Some eminent physicists concluded that Nature is definitely nonlocal and that it is acting according to a law of nonlocal randomness. According to these law perfectly random, but strongly correlated events, can be produced at the same time in far away locations and a local and causal explanation of their occurrence cannot be given. We strongly disagree with this conclusion and we prove the contrary by analysing in detail some influential finite sample proofs of Bell and CHSH inequalities and so called Quantum Randi Challenges. We also show how one can win so called Bell's game without violating locality of Nature. Nonlocal randomness is inconsistent with local quantum field theory, with standard model in elementary particle physics and with causal laws and adaptive dynamics prevailing in the surrounding us world. The experimental violation of Bell-type inequalities does not prove the nonlocality of Nature but it only confirms a contextual character of quantum observables and gives a strong argument against counterfactual definiteness and against a point of view according to which experimental outcomes are

  2. EPR paradox, quantum nonlocality and physical reality

    Science.gov (United States)

    Kupczynski, M.

    2016-03-01

    Eighty years ago Einstein, Podolsky and Rosen demonstrated that instantaneous reduction of wave function, believed to describe completely a pair of entangled physical systems, led to EPR paradox. The paradox disappears in statistical interpretation of quantum mechanics (QM) according to which a wave function describes only an ensemble of identically prepared physical systems. QM predicts strong correlations between outcomes of measurements performed on different members of EPR pairs in far-away locations. Searching for an intuitive explanation of these correlations John Bell analysed so called local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of QM and by experimental data. Several different local models were constructed and inequalities proven. Some eminent physicists concluded that Nature is definitely nonlocal and that it is acting according to a law of nonlocal randomness. According to these law perfectly random, but strongly correlated events, can be produced at the same time in far away locations and a local and causal explanation of their occurrence cannot be given. We strongly disagree with this conclusion and we prove the contrary by analysing in detail some influential finite sample proofs of Bell and CHSH inequalities and so called Quantum Randi Challenges. We also show how one can win so called Bell's game without violating locality of Nature. Nonlocal randomness is inconsistent with local quantum field theory, with standard model in elementary particle physics and with causal laws and adaptive dynamics prevailing in the surrounding us world. The experimental violation of Bell-type inequalities does not prove the nonlocality of Nature but it only confirms a contextual character of quantum observables and gives a strong argument against counterfactual definiteness and against a point of view according to which experimental outcomes are produced

  3. Study of CNT growth using nanocatalyst Ag precursor by HWC-VHF-PECVD

    International Nuclear Information System (INIS)

    Eliyana, Ajeng; Rosikin, Ahmad; Winata, Toto

    2015-01-01

    The study of CNT growth has been done by using silver (Ag) nanocatalyst as a guide precursor on corning glass 7059 substrate. The silver catalyst was prepared by the evaporation method by varying deposition time for 50, 25, and 14 seconds. The silver films were then annealed at temperature of 400°C for 4 hours. From Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) results the grain sizes are 65 nm, 57 nm, and 33 nm, and also the atomic compositions are 6,06%, 4,52%, and 3,73% for 14, 25 and 50 seconds samples, respectively. The 33 nm samples were then used for CNT growth by using Hot Wire Cell (HWC) – Very High Frequency (VHF) – Plasma Enhanced Chemical Vapor Deposition (PECVD) at 275 ° C deposition temperature and pressure of 300 mTorr. The rf power was varied from 8 to 20 watts, with deposition time for 60 minutes. The methane (CH4) 99.999% was used as Carbon sources. Hydrogen gas (H2) was used to etch the oxide layer formed during the pre-deposition process. The diameter and length for the CNT are 125 nm and 1.650 to 2.989 nm respectively

  4. Anisotropy of Doppler spectral parameters in the VHF radar observations at MU and White Sands

    Directory of Open Access Journals (Sweden)

    G. D. Nastrom

    2001-08-01

    Full Text Available Significant differences are found between the mean spectral widths from beams in the meridional plane and in the zonal plane at both the MU and the White Sands VHF radars. The spectral width in the beam directed perpendicular to the prevailing wind is greater than that in the beam parallel to the wind. The magnitudes of the differences in spectral width show a linear relationship with wind speed, with the greatest differences at the greatest wind speeds. The differences in spectral width show a positive correlation with the differences in backscattered power. The anisotropy in backscattered power is well-known and is usually attributed to aspect sensitivity effects. However, the anisotropy in spectral width does not appear to be due to the same mechanism, and while several hypotheses to account for this are considered, including finite range-volume effects, effects from the tilting of isentropic layers, and anisotropic turbulence effects, it is seen that each of these suggestions has its shortcomings.Key words. Meteorology and atmospheric dynamics (turbulence; instruments and techniques

  5. Study of CNT growth using nanocatalyst Ag precursor by HWC-VHF-PECVD

    Energy Technology Data Exchange (ETDEWEB)

    Eliyana, Ajeng; Rosikin, Ahmad; Winata, Toto, E-mail: toto@fi.itb.ac.id [Physics of Electronics Material Research Division, Physics Programme, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, West Java (Indonesia)

    2015-04-16

    The study of CNT growth has been done by using silver (Ag) nanocatalyst as a guide precursor on corning glass 7059 substrate. The silver catalyst was prepared by the evaporation method by varying deposition time for 50, 25, and 14 seconds. The silver films were then annealed at temperature of 400°C for 4 hours. From Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) results the grain sizes are 65 nm, 57 nm, and 33 nm, and also the atomic compositions are 6,06%, 4,52%, and 3,73% for 14, 25 and 50 seconds samples, respectively. The 33 nm samples were then used for CNT growth by using Hot Wire Cell (HWC) – Very High Frequency (VHF) – Plasma Enhanced Chemical Vapor Deposition (PECVD) at 275 ° C deposition temperature and pressure of 300 mTorr. The rf power was varied from 8 to 20 watts, with deposition time for 60 minutes. The methane (CH4) 99.999% was used as Carbon sources. Hydrogen gas (H2) was used to etch the oxide layer formed during the pre-deposition process. The diameter and length for the CNT are 125 nm and 1.650 to 2.989 nm respectively.

  6. VHF and HF radar measurements of E and R region plasma drifts at the magnetic equator

    International Nuclear Information System (INIS)

    Viswanathan, K.S.; Namboothiri, S.P.; Rao, P.B.

    1992-01-01

    Simultaneous observations of E region horizontal irregularity drifts by VHF backscatter radar and of F region vertical plasma drift by HF Doppler radar conducted during daytime on a few magnetically quiet days at Trivandrum (dip 0.2 degree N) are presented. A comparative study of the two measurements indicates broadly (1) a resemblance in the daytime changes of the E-W component between the electric field and (2) evidence of quasi-periodic electric field variations with periods ranging mostly from 1 to 2 hours. The electric fields derived from HF Doppler radar observations are somewhat lower than those deduced by HVHF radar observations. The correlation coefficient for the variations of the electric fields measured by the two experimental techniques is found to be in the range of about 0.5 to 0.9. The observed difference in the E and F region electric fields at the magnetic equator is discussed in terms of the measurement uncertainties and the limitations involved in deriving E-W electric fields. The observations are suggestive of a latitudinal variation in the E-W component of the electric field in the equatorial ionosphere

  7. Braked rotation of CH3 group in L-alanine monocrystals: temperature transformation of EPR spectrum

    International Nuclear Information System (INIS)

    Lemanov, V.V.; Sochava, L.S.

    2003-01-01

    EPR spectra temperature transformation of the irradiated alanine crystals is used for studying rotation of CH 3 methyl group in L-alamine monocrystals. 60 Co (2 x 10 4 Gy dose) was applied as a γ-radiation source. The simple method of experimental data processing which is reduced to obtaining the resonance lines width dependence on the temperature is used for the quantitative analysis of the spectrum temperature transformation. Temperature dependence of the CH 3 group rotation frequency is identified on the basis of these data. Activation energy U = 0.18 eV and pre-exponential multiplier ω 0 = 10 13 s -1 are determined from the EPR spectra temperature transformation which are in good agreement with values obtained earlier from the measurements of the proton spin-lattice relaxation in alanine polycrystal samples [ru

  8. EPR detection of foods preserved with ionizing radiation

    Science.gov (United States)

    Stachowicz, W.; Burlinska, G.; Michalik, J.

    1998-06-01

    The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition. No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays ( 60Co) and 10 MeV electrons were observed

  9. Software for evaluation of EPR-dosimetry performance

    International Nuclear Information System (INIS)

    Shishkina, E.A.; Timofeev, Yu.S.; Ivanov, D.V.

    2014-01-01

    Electron paramagnetic resonance (EPR) with tooth enamel is a method extensively used for retrospective external dosimetry. Different research groups apply different equipment, sample preparation procedures and spectrum processing algorithms for EPR dosimetry. A uniform algorithm for description and comparison of performances was designed and implemented in a new computer code. The aim of the paper is to introduce the new software 'EPR-dosimetry performance'. The computer code is a user-friendly tool for providing a full description of method-specific capabilities of EPR tooth dosimetry, from metrological characteristics to practical limitations in applications. The software designed for scientists and engineers has several applications, including support of method calibration by evaluation of calibration parameters, evaluation of critical value and detection limit for registration of radiation-induced signal amplitude, estimation of critical value and detection limit for dose evaluation, estimation of minimal detectable value for anthropogenic dose assessment and description of method uncertainty. (authors)

  10. A sub-Kelvin cryogen-free EPR system.

    Science.gov (United States)

    Melhuish, Simon J; Stott, Chloe; Ariciu, Ana-Maria; Martinis, Lorenzo; McCulloch, Mark; Piccirillo, Lucio; Collison, David; Tuna, Floriana; Winpenny, Richard

    2017-09-01

    We present an EPR instrument built for operation at Q band below 1K. Our cryogen-free Dewar integrates with a commercial electro-magnet and bridge. A description of the cryogenic and RF systems is given, along with the adaptations to the standard EPR experiment for operation at sub-Kelvin temperatures. As a first experiment, the EPR spectra of powdered Cr 12 O 9 (OH) 3 [Formula: see text] were measured. The sub-Kelvin EPR spectra agree well with predictions, and the performance of the sub-Kelvin system at 5K is compared to that of a commercial spectrometer. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Trichloroethylene Radicals: An EPR/SPIN Trapping Study

    National Research Council Canada - National Science Library

    Steel-Goodwin, Linda

    1995-01-01

    .... As part of the process to develop environmental and health effects criteria for base clean-up the initial radicals produced by TCE were studied by electron paramagnetic resonance spectroscopy (EPR...

  12. Reconfiguring Cooperative Work by Visualizing EPR on Large Projected Screens

    DEFF Research Database (Denmark)

    Simonsen, Jesper

    Simonsen, J. (2006): Reconfiguring Cooperative Work by Visualizing EPR on Large Projected Screens, Paper presented at the PDC 2006 workshop on: Reconfiguring Healthcare: Issues in Computer Supported Cooperative Work in Healthcare Environments. Participatory Design Conference, Trento, Italy, August...

  13. EPR and NMR detection of transient radicals and reaction products

    International Nuclear Information System (INIS)

    Trifunac, A.D.

    1981-01-01

    Magnetic resonance methods in radiation chemistry are illustrated. The most recent developments in pulsed EPR and NMR studies in pulse radiolysis are outlined with emphasis on the study of transient radicals and their reaction products. 12 figures

  14. EPR spectroscopy of complex biological iron-sulfur systems.

    Science.gov (United States)

    Hagen, Wilfred R

    2018-02-21

    From the very first discovery of biological iron-sulfur clusters with EPR, the spectroscopy has been used to study not only purified proteins but also complex systems such as respiratory complexes, membrane particles and, later, whole cells. In recent times, the emphasis of iron-sulfur biochemistry has moved from characterization of individual proteins to the systems biology of iron-sulfur biosynthesis, regulation, degradation, and implications for human health. Although this move would suggest a blossoming of System-EPR as a specific, non-invasive monitor of Fe/S (dys)homeostasis in whole cells, a review of the literature reveals limited success possibly due to technical difficulties in adherence to EPR spectroscopic and biochemical standards. In an attempt to boost application of System-EPR the required boundary conditions and their practical applications are explicitly and comprehensively formulated.

  15. EPR-based distance measurements at ambient temperature.

    Science.gov (United States)

    Krumkacheva, Olesya; Bagryanskaya, Elena

    2017-07-01

    Pulsed dipolar (PD) EPR spectroscopy is a powerful technique allowing for distance measurements between spin labels in the range of 2.5-10.0nm. It was proposed more than 30years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (TEPR as well as other approaches based on EPR (e.g., relaxation enhancement; RE). In this paper, we review the features of PD EPR and RE at ambient temperatures, in particular, requirements on electron spin phase memory time, ways of immobilization of biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Experimental EPR-steering using Bell-local states

    Science.gov (United States)

    Saunders, D. J.; Jones, S. J.; Wiseman, H. M.; Pryde, G. J.

    2010-11-01

    The concept of `steering' was introduced in 1935 by Schrödinger as a generalization of the EPR (Einstein-Podolsky-Rosen) paradox. It has recently been formalized as a quantum-information task with arbitrary bipartite states and measurements, for which the existence of entanglement is necessary but not sufficient. Previous experiments in this area have been restricted to an approach that followed the original EPR argument in considering only two different measurement settings per side. Here we demonstrate experimentally that EPR-steering occurs for mixed entangled states that are Bell local (that is, that cannot possibly demonstrate Bell non-locality). Unlike the case of Bell inequalities, increasing the number of measurement settings beyond two-we use up to six-significantly increases the robustness of the EPR-steering phenomenon to noise.

  17. EPR detection of foods preserved with ionizing radiation

    International Nuclear Information System (INIS)

    Stachowicz, W.; Burlinska, G.; Michalik, J.

    1998-01-01

    The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to the beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition. No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays ( 60 Co) and 10 MeV electrons were observed

  18. Decomposition of spectra in EPR dosimetry using the matrix method

    International Nuclear Information System (INIS)

    Sholom, S.V.; Chumak, V.V.

    2003-01-01

    The matrix method of EPR spectra decomposition is developed and adapted for routine application in retrospective EPR dosimetry with teeth. According to this method, the initial EPR spectra are decomposed (using methods of matrix algebra) into several reference components (reference matrices) that are specific for each material. Proposed procedure has been tested on the example of tooth enamel. Reference spectra were a spectrum of an empty sample tube and three standard signals of enamel (two at g=2.0045, both for the native signal and one at g perpendicular =2.0018, g parallel =1.9973 for the dosimetric signal). Values of dosimetric signals obtained using the given method have been compared with data obtained by manual manipulation of spectra, and good coincidence was observed. This allows considering the proposed method as potent for application in routine EPR dosimetry

  19. EPR of radiation defects in lithium-oxyfluoride glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Fedotovs, A; Rogulis, U; Sarakovskis, A; Dimitrocenko, L, E-mail: andris-f@navigator.l [Institute of Solid State Physics, University of Latvia, Kengaraga st. 8, LV-1063, Riga (Latvia)

    2010-11-01

    We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF{sub 3} crystalline phase.

  20. EPR of radiation defects in lithium-oxyfluoride glass ceramics

    Science.gov (United States)

    Fedotovs, A.; Rogulis, U.; Sarakovskis, A.; Dimitrocenko, L.

    2010-11-01

    We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF3 crystalline phase.

  1. EPR detection of foods preserved with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Stachowicz, W.; Burlinska, G.; Michalik, J

    1998-06-01

    The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to the beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition. No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays ({sup 60}Co) and 10 MeV electrons were observed.

  2. A dozen useful tips on how to minimise the influence of sources of error in quantitative electron paramagnetic resonance (EPR) spectroscopy-A review

    International Nuclear Information System (INIS)

    Mazur, Milan

    2006-01-01

    The principal and the most important error sources in quantitative electron paramagnetic resonance (EPR) measurements arising from sample-associated factors are the influence of the variation of the sample material (dielectric constant), sample size and shape, sample tube wall thickness, and sample orientation and positioning within the microwave cavity on the EPR signal intensity. Variation in these parameters can cause significant and serious errors in the primary phase of quantitative EPR analysis (i.e., data acquisition). The primary aim of this review is to provide useful suggestions, recommendations and simple procedures to minimise the influence of such primary error sources in quantitative EPR measurements. According to the literature, as well as results obtained in our EPR laboratory, the following are recommendations for samples, which are compared in quantitative EPR studies: (i) the shape of all samples should be identical; (ii) the position of the sample/reference in the cavity should be identical; (iii) a special alignment procedure for precise sample positioning within the cavity should be adopted; (iv) a special/consistent procedure for sample packing for a powder material should be used; (v) the wall thickness of sample tubes should be identical; (vi) the shape and wall thickness of quartz Dewars, where used, should be identical; (vii) where possible a double TE 104 cavity should be used in quantitative EPR spectroscopy; (viii) the dielectric properties of unknown and standard samples should be as close as possible; (ix) sample length less than double the cavity length should be used; (x) the optimised sample geometry for the X-band cavity is a 30 mm-length capillary with i.d. less then 1.5 mm; (xi) use of commercially distributed software for post-recording spectra manipulation is a basic necessity; and (xii) the sample and laboratory temperature should be kept constant during measurements. When the above recommendations and procedures were used

  3. Most advanced HTP fuel assembly design for EPR

    International Nuclear Information System (INIS)

    Francillon, Eric; Kiehlmann, Horst-Dieter

    2006-01-01

    End 2003, the Finnish electricity utility Teollisuuden Voima Oy (TVO) signed the contract for building an EPR in Olkiluoto (Finland). Mid 2004, the French electricity utility EDF selected an EPR to be built in France. In 2005, Framatome ANP, an AREVA and Siemens company, announced that they will be pursuing a design certification in the U.S. The EPR development is based on the latest PWR product lines of former Framatome (N4) and Siemens Nuklear (Konvoi). As an introductory part, different aspects of the EPR core characteristics connected to fuel assembly design are presented. It includes means of ensuring reactivity control like hybrid AIC/B4C control rod absorbers and gadolinium as burnable absorber integrated in fuel rods, and specific options for in-core instrumentation, such as Aeroball type instrumentation. Then the design requirements for the EPR fuel assembly are presented in term of very high burnup capacity, rod cladding and fuel assembly reliability. Framatome ANP fuel assembly product characteristics meeting these requirements are then described. EPR fuel assembly design characteristics benefit from the experience feedback of the latest fuel assembly products designed within Framatome ANP, leading to resistance to assembly deformation, high fuel rod restraint and prevention of handling hazards. EPR fuel assembly design features the best components composing the cornerstones of the upgraded family of fuel assemblies that FRAMATOME ANP proposes today. This family is based on a set of common characteristics and associated features, which include the HMP grid as bottom end spacer, the MONOBLOC guide tube and the Robust FUELGUARD as lower tie plate, the use of the M5 Alloy, as cladding and structure material. This fully re-crystallized, ternary Zr-Nb-O alloy produces radically improved in-reactor corrosion, very low hydrogen uptake and growth and an excellent creep behavior, which are described there. EPR fuel assembly description also includes fuel rod

  4. EPR-based distance measurements at ambient temperature

    Science.gov (United States)

    Krumkacheva, Olesya; Bagryanskaya, Elena

    2017-07-01

    Pulsed dipolar (PD) EPR spectroscopy is a powerful technique allowing for distance measurements between spin labels in the range of 2.5-10.0 nm. It was proposed more than 30 years ago, and nowadays is widely used in biophysics and materials science. Until recently, PD EPR experiments were limited to cryogenic temperatures (T biomolecules, the influence of a linker between the spin probe and biomolecule, and future opportunities.

  5. Combining EPR spectroscopy and X-ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals.

    Science.gov (United States)

    Consentius, Philipp; Gohlke, Ulrich; Loll, Bernhard; Alings, Claudia; Heinemann, Udo; Wahl, Markus C; Risse, Thomas

    2017-08-09

    Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system.

  6. Emergency EPR and OSL dosimetry with table vitamins and minerals.

    Science.gov (United States)

    Sholom, S; McKeever, S W S

    2016-12-01

    Several table vitamins, minerals and L-lysine amino acid have been preliminarily tested as potential emergency dosemeters using electron paramagnetic resonance (EPR) and optically stimulated luminescence (OSL) techniques. Radiation-induced EPR signals were detected in samples of vitamin B2 and L-lysine while samples of multivitamins of different brands as well as mineral Mg demonstrated prominent OSL signals after exposure to ionizing radiation doses. Basic dosimetric properties of the radiation-sensitive substances were studied, namely dose response, fading of the EPR or OSL signals and values of minimum measurable doses (MMDs). For EPR-sensitive samples, the EPR signal is converted into units of dose using a linear dose response and correcting for fading using the measured fading dependence. For OSL-sensitive materials, a multi-aliquot, enhanced-temperature protocol was developed to avoid the problem of sample sensitization and to minimize the influence of signal fading. The sample dose in this case is also evaluated using the dose response and fading curves. MMDs of the EPR-sensitive samples were below 2 Gy while those of the OSL-sensitive materials were below 500 mGy as long as the samples are analyzed within 1 week after exposure. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Correlations between the particles in the EPR-paradox

    Energy Technology Data Exchange (ETDEWEB)

    Treder, H.J. (Akademie der Wissenschaften der DDR, Potsdam-Babelsberg. Einstein-Laboratorium fuer Theoretische Physik)

    1984-03-01

    The Einstein-Podolsky-Rosen 'gedanken-experiment' does not imply non-local interactions or an 'action-at-a-distance'. Contrary, the EPR proves the measurements at one particle does not have influences at canonical variables of the other particles if the quantum-mechanical commutation relations are true. But, the EPR implies correlations between the particles which come in by 'subjective knowledge'. These correlations are a priori informations about the relative motion or, complementarily, about the motion of the center of mass. The impression of an action-at-a-distance is produced by the use of usual particle coordinates in the EPR-arrangements. The discussion of the Einstein-Podolsky-Rosen 'gedanken-experiment' (EPR) has been going on over fifty years. Einstein, Podolsky, and Rosen formulated their famous paradox in 1935, and in the discussion between N. Bohr (1935, 1949) and Einstein (1936, 1948); A. Einstein (1948) made his point that the EPR implied an 'action-at-a-distance' for quantum-mechanical particles (without obvious classical interactions). His argument is the starting point for the recent discussion about EPR and causality (see A. Aspect 1981).

  8. Pulsed-High Field/High-Frequency EPR Spectroscopy

    Science.gov (United States)

    Fuhs, Michael; Moebius, Klaus

    Pulsed high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy is used to disentangle many kinds of different effects often obscured in continuous wave (cw) EPR spectra at lower magnetic fields/microwave frequencies. While the high magnetic field increases the resolution of G tensors and of nuclear Larmor frequencies, the high frequencies allow for higher time resolution for molecular dynamics as well as for transient paramagnetic intermediates studied with time-resolved EPR. Pulsed EPR methods are used for example for relaxation-time studies, and pulsed Electron Nuclear DOuble Resonance (ENDOR) is used to resolve unresolved hyperfine structure hidden in inhomogeneous linewidths. In the present article we introduce the basic concepts and selected applications to structure and mobility studies on electron transfer systems, reaction centers of photosynthesis as well as biomimetic models. The article concludes with an introduction to stochastic EPR which makes use of an other concept for investigating resonance systems in order to increase the excitation bandwidth of pulsed EPR. The limited excitation bandwidth of pulses at high frequency is one of the main limitations which, so far, made Fourier transform methods hardly feasible.

  9. EPR study on non- and gamma-irradiated herbal pills

    International Nuclear Information System (INIS)

    Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N.D.

    2011-01-01

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show 'cellulose-like' EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  10. EPR study on non- and gamma-irradiated herbal pills

    Energy Technology Data Exchange (ETDEWEB)

    Aleksieva, K., E-mail: katerina_bas@abv.b [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Lagunov, O. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimov, K. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Yordanov, N.D. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2011-06-15

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048{+-}0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show 'cellulose-like' EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  11. EPR study on non- and gamma-irradiated herbal pills

    Science.gov (United States)

    Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N. D.

    2011-06-01

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show "cellulose-like" EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  12. EPC projects for EPR Flamanville 3 NPP

    International Nuclear Information System (INIS)

    Diaz, J.I.; Polo, J.; Aymerich, E.; Cubian, B.

    2010-01-01

    IBERDROLA Ingenieria y Construccion is carrying out a handful of activities in the EPR Flamanville 3 -FA3 NPP- context since 2007 matching oriented to position the company in the emerging marketplace of new nuclear power plants Generation III+, whose expectation for the next years is highly promising. IBERDROLA Ingenieria y Construccion leads 5 EPC -Engineering, Procurement and Commissioning- projects for FA3 NPP from the Nuclear Island till Sea Water Pumping Station as follows: - Design, procurement. fabrication, installation and testing of 21 shell and tubes heat-exchangers for the nuclear island. 12 out of these 17 HXs are conventional and will be designed according to ASME BPV code Section VIII and have to comply with PED 97/23/CE and ESPN. The remaining 5 HXs are nuclear and will be designed according to ASME BPV code Section III and have also to comply with PED and ESPN. - Design, procurement, fabrication and assembly of 9 demineralizers for different plant systems. Three of these Important To Safety (IPS) equipments have been manufactured according with ASME VIII codes and six of them with EN 13445 code plus additional requirements to comply with PED and final client requirements for nuclear island. - Design, fabrication and installation of qualified travelling water screening filters. The equipments furnished will be two nuclear safety qualified filters and associated equipment (cleaning water system and control system). Additionally some auxiliary devices such as grids, automatic trash rakes and stop gates are included in the contract. - Engineering, procurement, fabrication, erection and commissioning for the condensate treatment plant. This system includes a demineralizer tank, 5 filters, reactive injection mixer, pneumatic and manual valves, piping and instrumentation and control systems. - Engineering, procurement erection and commissioning for the electro-chlorination plant to protect the IPS piping for Condensate Water System for FA3. This system

  13. EPC projects for EPR Flamanville 3 NPP

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, J.I.; Polo, J.; Aymerich, E.; Cubian, B. [Nuclear Generation Department, Iberdrola Ingenieria y Construccion, Avda. Manoteras 20, 28050 Madrid (Spain)

    2010-07-01

    IBERDROLA Ingenieria y Construccion is carrying out a handful of activities in the EPR Flamanville 3 -FA3 NPP- context since 2007 matching oriented to position the company in the emerging marketplace of new nuclear power plants Generation III+, whose expectation for the next years is highly promising. IBERDROLA Ingenieria y Construccion leads 5 EPC -Engineering, Procurement and Commissioning- projects for FA3 NPP from the Nuclear Island till Sea Water Pumping Station as follows: - Design, procurement. fabrication, installation and testing of 21 shell and tubes heat-exchangers for the nuclear island. 12 out of these 17 HXs are conventional and will be designed according to ASME BPV code Section VIII and have to comply with PED 97/23/CE and ESPN. The remaining 5 HXs are nuclear and will be designed according to ASME BPV code Section III and have also to comply with PED and ESPN. - Design, procurement, fabrication and assembly of 9 demineralizers for different plant systems. Three of these Important To Safety (IPS) equipments have been manufactured according with ASME VIII codes and six of them with EN 13445 code plus additional requirements to comply with PED and final client requirements for nuclear island. - Design, fabrication and installation of qualified travelling water screening filters. The equipments furnished will be two nuclear safety qualified filters and associated equipment (cleaning water system and control system). Additionally some auxiliary devices such as grids, automatic trash rakes and stop gates are included in the contract. - Engineering, procurement, fabrication, erection and commissioning for the condensate treatment plant. This system includes a demineralizer tank, 5 filters, reactive injection mixer, pneumatic and manual valves, piping and instrumentation and control systems. - Engineering, procurement erection and commissioning for the electro-chlorination plant to protect the IPS piping for Condensate Water System for FA3. This system

  14. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    Full Text Available A statistical investigation of the relationship between VHF radar auroral backscatter intensity and Doppler velocity has been undertaken with data collected from 8 years operation of the Wick site of the Sweden And Britain Radar-auroral Experiment (SABRE. The results indicate three different regimes within the statistical data set; firstly, for Doppler velocities <200 m s–1, the backscatter intensity (measured in decibels remains relatively constant. Secondly, a linear relationship is observed between the backscatter intensity (in decibels and Doppler velocity for velocities between 200 m s–1 and 700 m s–1. At velocities greater than 700 m s–1 the backscatter intensity saturates at a maximum value as the Doppler velocity increases. There are three possible geophysical mechanisms for the saturation in the backscatter intensity at high phase speeds: a saturation in the irregularity turbulence level, a maximisation of the scattering volume, and a modification of the local ambient electron density. There is also a difference in the dependence of the backscatter intensity on Doppler velocity for the flow towards and away from the radar. The results for flow towards the radar exhibit a consistent relationship between backscatter intensity and measured velocities throughout the solar cycle. For flow away from the radar, however, the relationship between backscatter intensity and Doppler velocity varies during the solar cycle. The geometry of the SABRE system ensures that flow towards the radar is predominantly associated with the eastward electrojet, and flow away is associated with the westward electrojet. The difference in the backscatter intensity variation as a function of Doppler velocity is attributed to asymmetries between the eastward and westward electrojets and the geophysical parameters controlling the backscatter amplitude.

  15. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    1996-08-01

    Full Text Available A statistical investigation of the relationship between VHF radar auroral backscatter intensity and Doppler velocity has been undertaken with data collected from 8 years operation of the Wick site of the Sweden And Britain Radar-auroral Experiment (SABRE. The results indicate three different regimes within the statistical data set; firstly, for Doppler velocities <200 m s–1, the backscatter intensity (measured in decibels remains relatively constant. Secondly, a linear relationship is observed between the backscatter intensity (in decibels and Doppler velocity for velocities between 200 m s–1 and 700 m s–1. At velocities greater than 700 m s–1 the backscatter intensity saturates at a maximum value as the Doppler velocity increases. There are three possible geophysical mechanisms for the saturation in the backscatter intensity at high phase speeds: a saturation in the irregularity turbulence level, a maximisation of the scattering volume, and a modification of the local ambient electron density. There is also a difference in the dependence of the backscatter intensity on Doppler velocity for the flow towards and away from the radar. The results for flow towards the radar exhibit a consistent relationship between backscatter intensity and measured velocities throughout the solar cycle. For flow away from the radar, however, the relationship between backscatter intensity and Doppler velocity varies during the solar cycle. The geometry of the SABRE system ensures that flow towards the radar is predominantly associated with the eastward electrojet, and flow away is associated with the westward electrojet. The difference in the backscatter intensity variation as a function of Doppler velocity is attributed to asymmetries between the eastward and westward electrojets and the geophysical parameters controlling the backscatter amplitude.

  16. Effect of solar and magnetic activity on VHF scintillations near the equatorial anomaly crest

    Directory of Open Access Journals (Sweden)

    R. P. Singh

    2004-09-01

    Full Text Available The VHF amplitude scintillation recorded during the period January 1991 to December 1993 in the declining phase of a solar cycle and April 1998 to December 1999 in the ascending phase of the next solar cycle at Varanasi (geogr. lat.=25.3°, long.=83.0°, dip=37°N have been analyzed to study the behavior of ionospheric irregularities during active solar periods and magnetic storms. It is shown that irregularities occur at arbitrary times and may last for <30min. A rise in solar activity increases scintillations during winter (November-February and near equinoxes (March-April; September-October, whereas it depresses the scintillations during the summer (May-July. In general, the role of magnetic activity is to suppress scintillations in the pre-midnight period and to increase it in the post-midnight period during equinox and winter seasons, whilst during summer months the effect is reversed. The pre-midnight scintillation is sometimes observed when the main phase of Dst corresponds to the pre-midnight period. The annual variation shows suppression of scintillations on disturbed days, both during pre-midnight and post-midnight period, which becomes more effective during years of high solar activity. It is observed that for magnetic storms for which the recovery phase starts post-midnight, the probability of occurrence of irregularities is enhanced during this time. If the magnetic storm occurred during daytime, then the probability of occurrence of scintillations during the night hours is decreased. The penetration of magnetospheric electric fields to the magnetic equator affects the evolution of low-latitude irregularities. A delayed disturbance dynamo electric field also affects the development of irregularities.

  17. Simulation of Controller Pilot Data Link Communications over VHF Digital Link Mode 3

    Science.gov (United States)

    Bretmersky, Steven C.; Murawski, Robert; Nguyen, Thanh C.; Raghavan, Rajesh S.

    2004-01-01

    The Federal Aviation Administration (FAA) has established an operational plan for the future Air Traffic Management (ATM) system, in which the Controller Pilot Data Link Communications (CPDLC) is envisioned to evolve into digital messaging that will take on an ever increasing role in controller to pilot communications, significantly changing the way the National Airspace System (NAS) is operating. According to FAA, CPDLC represents the first phase of the transition from the current analog voice system to an International Civil Aviation Organization (ICAO) compliant system in which digital communication becomes the alternate and perhaps primary method of routine communication. The CPDLC application is an Air Traffic Service (ATS) application in which pilots and controllers exchange messages via an addressed data link. CPDLC includes a set of clearance, information, and request message elements that correspond to existing phraseology employed by current Air Traffic Control (ATC) procedures. These message elements encompass altitude assignments, crossing constraints, lateral deviations, route changes and clearances, speed assignments, radio frequency assignments, and various requests for information. The pilot is provided with the capability to respond to messages, to request clearances and information, to report information, and to declare/rescind an emergency. A 'free text' capability is also provided to exchange information not conforming to defined formats. This paper presents simulated results of the aeronautical telecommunication application Controller Pilot Data Link Communications over VHF Digital Link Mode 3 (VDL Mode 3). The objective of this simulation study was to determine the impact of CPDLC traffic loads, in terms of timely message delivery and capacity of the VDL Mode 3 subnetwork. The traffic model is based on and is used for generating air/ground messages with different priorities. Communication is modeled for the en route domain of the Cleveland

  18. Flamanville 3 EPR, Safety Assessment and On-site Inspections

    International Nuclear Information System (INIS)

    Piedagnel, Corinne; Tarallo, Francois; Monnot, Bernard

    2011-01-01

    As a Technical Support Organisation of the French Safety Authority (ASN), the IRSN carries out the safety assessment of EPR project design and participates in the ASN inspections performed at the construction site and in factories. The design assessment consists in defining the safety functions which should be ensured by civil structures, evaluating the EPR Technical Code for Civil works (ETC-C) in which EdF has defined design criteria and construction rules, and carrying out a detailed assessment of a selection of safety-related structures. Those detailed assessments do not consist of a technical control but of an analysis whose objectives are to ensure that design and demonstrations are robust, in accordance with safety and regulatory rules. Most assessments led IRSN to ask EdF to provide additional justification sometimes involving significant modifications. In the light of those complementary justifications and modifications, IRSN concluded that assessments carried out on design studies were globally satisfactory. The participation of IRSN to the on-site inspections led by ASN is a part of the global control of the compliance of the reactor with its safety objectives. For that purpose IRSN has defined a methodology and an inspection program intended to ASN: based on safety functions associated with civil works (confinement and resistance to aggressions), the corresponding behaviour requirements are identified and linked to a list of main civil works elements. During the inspections, deviations to the project's technical specifications or to the rules of the art were pointed out by IRSN. Those deviations cover various items, such as concrete fabrication, concrete pouring methodology, lack of reinforcement in some structures, unadapted welding procedures of the containment leak-tight steel liner and unsatisfactory treatment of concreting joints. The analysis of those problems has revealed flaws in the organisation of the contractors teams together with an

  19. Saturation recovery EPR spin-labeling method for quantification of lipids in biological membrane domains.

    Science.gov (United States)

    Mainali, Laxman; Camenisch, Theodore G; Hyde, James S; Subczynski, Witold K

    2017-12-01

    The presence of integral membrane proteins induces the formation of distinct domains in the lipid bilayer portion of biological membranes. Qualitative application of both continuous wave (CW) and saturation recovery (SR) electron paramagnetic resonance (EPR) spin-labeling methods allowed discrimination of the bulk, boundary, and trapped lipid domains. A recently developed method, which is based on the CW EPR spectra of phospholipid (PL) and cholesterol (Chol) analog spin labels, allows evaluation of the relative amount of PLs (% of total PLs) in the boundary plus trapped lipid domain and the relative amount of Chol (% of total Chol) in the trapped lipid domain [ M. Raguz, L. Mainali, W. J. O'Brien, and W. K. Subczynski (2015), Exp. Eye Res., 140:179-186 ]. Here, a new method is presented that, based on SR EPR spin-labeling, allows quantitative evaluation of the relative amounts of PLs and Chol in the trapped lipid domain of intact membranes. This new method complements the existing one, allowing acquisition of more detailed information about the distribution of lipids between domains in intact membranes. The methodological transition of the SR EPR spin-labeling approach from qualitative to quantitative is demonstrated. The abilities of this method are illustrated for intact cortical and nuclear fiber cell plasma membranes from porcine eye lenses. Statistical analysis (Student's t -test) of the data allowed determination of the separations of mean values above which differences can be treated as statistically significant ( P ≤ 0.05) and can be attributed to sources other than preparation/technique.

  20. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    International Nuclear Information System (INIS)

    Aragno, D.; Fattibene, P.; Onori, S.

    2000-01-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO 2 -signal of intensity similar to that induced by a dose of about 2 mGy of 60 Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60 Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined. (author)

  1. Structural Characterization of Polymer-Clay Nanocomposites Prepared by Co-Precipitation Using EPR Techniques

    Directory of Open Access Journals (Sweden)

    Udo Kielmann

    2014-02-01

    Full Text Available Polymer-clay nanocomposites (PCNCs containing either a rubber or an acrylate polymer were prepared by drying or co-precipitating polymer latex and nanolayered clay (synthetic and natural suspensions. The interface between the polymer and the clay nanoparticles was studied by electron paramagnetic resonance (EPR techniques by selectively addressing spin probes either to the surfactant layer (labeled stearic acid or the clay surface (labeled catamine. Continuous-wave (CW EPR studies of the surfactant dynamics allow to define a transition temperature T* which was tentatively assigned to the order-disorder transition of the surfactant layer. CW EPR studies of PCNC showed that completely exfoliated nanoparticles coexist with agglomerates. HYSCORE spectroscopy in PCNCs showed couplings within the probe −assigned with DFT computations− and couplings with nuclei of the environment, 1H and 23Na for the surfactant layer probe, and 29Si, 7Li, 19F and 23Na for the clay surface probe. Analysis of these couplings indicates that the integrity of the surfactant layer is conserved and that there are sizeable ionic regions containing sodium ions directly beyond the surfactant layer. Simulations of the very weak couplings demonstrated that the HYSCORE spectra are sensitive to the composition of the clay and whether or not clay platelets stack.

  2. Single crystal EPR determination of the quantum energy level structure for Fe8 molecular clusters

    Science.gov (United States)

    Maccagnano, S.; Hill, S.; Negusse, E.; Lussier, A.; Mola, M. M.; Achey, R.; Dalal, N. S.

    2001-05-01

    Using a high sensitivity resonance cavity technique,^1 we are able to obtain high field/frequency (up to 9 tesla/210 GHz) EPR spectra for oriented single crystals of [Fe_8O_2(OH)_12(tacn)_6]Br_8.9H_2O (or Fe8 for short). Extrapolating the frequency dependence of transitions to zero-field (for any orientation of the field) allows us to directly, and accurately (to within 0.5 percent), determine the first five zero-field splittings, which are in reasonable agreement with recent inelastic neutron studies.^2 The dependence of these splittings on the applied field strength, and its orientation with respect to the crystal, enables us to identify (to within 1^o) the easy, intermediate and hard magnetic axes. Subsequent analysis of EPR spectra for field parallel to the easy axis yields a value of for gz which is appreciably different from the value assumed in a recent high field EPR study by Barra et al.^3 ^1 M.M. Mola, S. Hill, P. Goy, and M. Gross, Rev. Sci. Inst. 71, 186 (2000). ^2 R. Caciuffo, G. Amoretti, R. Sessoli, A. Caneschi, and D. Gatteschi, Phys. Rev. Lett. 81, 4744 (1998). ^3 A. L. Barra, D. Gatteschi, and R. Sessoli, cond?mat/0002386 (Feb, 2000).

  3. An XRPD and EPR spectroscopy study of microcrystalline calcite bioprecipitated by Bacillus subtilis

    Science.gov (United States)

    Perito, B.; Romanelli, M.; Buccianti, A.; Passaponti, M.; Montegrossi, G.; Di Benedetto, F.

    2018-05-01

    We report in this study the first XRPD and EPR spectroscopy characterisation of a biogenic calcite, obtained from the activity of the bacterium Bacillus subtilis. Microcrystalline calcite powders obtained from bacterial culture in a suitable precipitation liquid medium were analysed without further manipulation. Both techniques reveal unusual parameters, closely related to the biological source of the mineral, i.e., to the bioprecipitation process and in particular to the organic matrix observed inside calcite. In detail, XRPD analysis revealed that bacterial calcite has slightly higher c/a lattice parameters ratio than abiotic calcite. This correlation was already noticed in microcrystalline calcite samples grown by bio-mineralisation processes, but it had never been previously verified for bacterial biocalcites. EPR spectroscopy evidenced an anomalously large value of W 6, a parameter that can be linked to occupation by different chemical species in the next nearest neighbouring sites. This parameter allows to clearly distinguish bacterial and abiotic calcite. This latter achievement was obtained after having reduced the parameters space into an unbiased Euclidean one, through an isometric log-ratio transformation. We conclude that this approach enables the coupled use of XRPD and EPR for identifying the traces of bacterial activity in fossil carbonate deposits.

  4. In Quest of the Alanine R3 Radical: Multivariate EPR Spectral Analyses of X-Irradiated Alanine in the Solid State.

    Science.gov (United States)

    Jåstad, Eirik O; Torheim, Turid; Villeneuve, Kathleen M; Kvaal, Knut; Hole, Eli O; Sagstuen, Einar; Malinen, Eirik; Futsaether, Cecilia M

    2017-09-28

    The amino acid l-α-alanine is the most commonly used material for solid-state electron paramagnetic resonance (EPR) dosimetry, due to the formation of highly stable radicals upon irradiation, with yields proportional to the radiation dose. Two major alanine radical components designated R1 and R2 have previously been uniquely characterized from EPR and electron-nuclear double resonance (ENDOR) studies as well as from quantum chemical calculations. There is also convincing experimental evidence of a third minor radical component R3, and a tentative radical structure has been suggested, even though no well-defined spectral signature has been observed experimentally. In the present study, temperature dependent EPR spectra of X-ray irradiated polycrystalline alanine were analyzed using five multivariate methods in further attempts to understand the composite nature of the alanine dosimeter EPR spectrum. Principal component analysis (PCA), maximum likelihood common factor analysis (MLCFA), independent component analysis (ICA), self-modeling mixture analysis (SMA), and multivariate curve resolution (MCR) were used to extract pure radical spectra and their fractional contributions from the experimental EPR spectra. All methods yielded spectral estimates resembling the established R1 spectrum. Furthermore, SMA and MCR consistently predicted both the established R2 spectrum and the shape of the R3 spectrum. The predicted shape of the R3 spectrum corresponded well with the proposed tentative spectrum derived from spectrum simulations. Thus, results from two independent multivariate data analysis techniques strongly support the previous evidence that three radicals are indeed present in irradiated alanine samples.

  5. Olkiluoto 3: Finland has chosen a EPR

    International Nuclear Information System (INIS)

    Brummer, S.

    2003-01-01

    According to the Finn law any nuclear project has to be declared conformed to the general interest of the country by the government and then has to be approved by the parliament. In may 2002 the Finn parliament approved the project of the TVO company: the construction of a new nuclear unit on the Olkiluoto site and the direct and definitive disposal of spent fuels in the granite underground layers of the same site. The project was agreed with 109 votes for and 92 against. In september 2002 an international invitation to tender was launched and 4 companies made proposals: Westinghouse, Atomstroexport, Framatome-ANP and General Electric. Westinghouse withdrew its offer some time later. In october 2003 TVO announced that the unit will be a 1600 MW EPR (European pressurized reactor) built by Framatome-ANP. The construction work will begin in spring 2005 and the unit is scheduled to enter into service in 2009. At that time the contribution of nuclear energy to the Finn energy production will reach 35%. (A.C.)

  6. Pulsed EPR for studying silver clusters

    International Nuclear Information System (INIS)

    Michalik, J.; Wasowicz, T.; Sadlo, J.; Reijerse, E.J.; Kevan, L.

    1996-01-01

    The cationic silver clusters of different nuclearity have been produced by radiolysis of zeolite A and SAPO molecular sieves containing Ag + as exchangeable cations. The pulsed EPR spectroscopy has been applied for studying the local environment of silver cluster in order to understand the mechanism of cluster formation and stabilization. the electron spin echo modulation (ESEM) results on Ag 6 n+ cluster in dehydration zeolite A indicate that the hexameric silver is stabilized only in sodalite cages which are surrounded by α-cages containing no water molecules. Trimeric silver clusters formed in hydrated A zeolites strongly interact with water, thus the paramagnetic center can be considered as a cluster-water adduct. In SAPO-molecular sieves, silver clusters are formed only in the presence of adsorbed alcohol molecules. From ESEM it is determined that Ag 4 n+ in SAPO-42 is stabilized in α cages, where it is directly coordinated by two methanol molecules. Dimeric silver, Ag 2 + in SAPO-5 and SAPO-11 is located in 6-ring channels and interacts with three CH 3 OH molecules, each in different 10 ring or 12 ring channels. The differences of Ag 2 + stability in SAPO-5 and SAPO-11 are also discussed. (Author)

  7. EPR by Areva. The path of greatest certainty

    International Nuclear Information System (INIS)

    2008-01-01

    AREVA's Evolutionary Power Reactor (EPR) is the first Generation III+ reactor design currently being built to answer the world's growing demand for clean and reliable electricity generation. Already under construction in Finland, France and China, the EPR is also being considered by America, United Kingdom, South Africa and other countries for the development of their nuclear fleet. The EPR is now clearly destined to become the mainstay of standardized, efficient reactor fleets around the globe. AREVA's EPR incorporates unbeatable know-how provided by an uninterrupted track record of reactor building activities and backed by decades of feedback experience from operating PWRs, including the most recent. The EPR is a Franco-German initiative which benefited from the stringent scrutiny of safety authorities from both countries, at each stage of the project. The EPR has already secured construction licenses from two of the world's most demanding safety authorities in France and Finland and is currently in line for a design certification and a combined construction and operating license (COL) in the USA. It is also taking part in the licensing process recently launched in the United Kingdom. Europe's leading utilities have granted the EPR their approval under the 'European Utilities Requirements' and have further expressed individual interest in the design and performance of the EPR for their businesses. AREVA is the only Gen III+ reactor constructor in the world with ongoing building experience. To date, AREVA is the only vendor who has the necessary field experience that future customers can benefit: - Detailed design completed; - Experience feedback from 87 PWR; - 3 projects going on; - Continuous PWR experience in design and construction. Close to 100% of the EPR primary circuit heavy components are sourced directly from AREVA's integrated plants. Engineering, manufacturing, services and fuel cycle management are totally integrated and mastered by AREVA. From its

  8. EPR by Areva. The path of greatest certainty

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    AREVA's Evolutionary Power Reactor (EPR) is the first Generation III+ reactor design currently being built to answer the world's growing demand for clean and reliable electricity generation. Already under construction in Finland, France and China, the EPR is also being considered by America, United Kingdom, South Africa and other countries for the development of their nuclear fleet. The EPR is now clearly destined to become the mainstay of standardized, efficient reactor fleets around the globe. AREVA's EPR incorporates unbeatable know-how provided by an uninterrupted track record of reactor building activities and backed by decades of feedback experience from operating PWRs, including the most recent. The EPR is a Franco-German initiative which benefited from the stringent scrutiny of safety authorities from both countries, at each stage of the project. The EPR has already secured construction licenses from two of the world's most demanding safety authorities in France and Finland and is currently in line for a design certification and a combined construction and operating license (COL) in the USA. It is also taking part in the licensing process recently launched in the United Kingdom. Europe's leading utilities have granted the EPR their approval under the 'European Utilities Requirements' and have further expressed individual interest in the design and performance of the EPR for their businesses. AREVA is the only Gen III+ reactor constructor in the world with ongoing building experience. To date, AREVA is the only vendor who has the necessary field experience that future customers can benefit: - Detailed design completed; - Experience feedback from 87 PWR; - 3 projects going on; - Continuous PWR experience in design and construction. Close to 100% of the EPR primary circuit heavy components are sourced directly from AREVA's integrated plants. Engineering, manufacturing, services and fuel cycle management are totally

  9. The effect of thermal treatment on radiation-induced EPR signals in tooth enamel

    International Nuclear Information System (INIS)

    Vorona, I.P.; Ishchenko, S.S.; Baran, N.P.

    2005-01-01

    The effect of thermal treatment on the radiation-induced EPR spectrum of tooth enamel was studied. Annealing before sample irradiation was found to increase enamel radiation sensitivity by more than 40%. Depending on the annealing conditions the EPR signals of three supplementary radiation radicals were observed in addition to the main signal caused by CO 2 - radicals. It was found that the presence of these signals in the enamel EPR spectra provides evidence of sample annealing. The possibility of obtaining information about sample history by studying the additional EPR signals is discussed. It can be important to EPR dating and EPR dosimetry

  10. Estimation of mesospheric vertical winds from a VHF meteor radar at King Sejong Station, Antarctica (62.2S, 58.8W)

    Science.gov (United States)

    Kim, Y.; Lee, C.; Kim, J.; Jee, G.

    2013-12-01

    For the first time, vertical winds near the mesopause region were estimated from radial velocities of meteor echoes detected by a VHF meteor radar at King Sejong Station (KSS) in 2011 and 2012. Since the radar usually detects more than a hundred echoes every hour in an altitude bin of 88 - 92 km, much larger than other radars, we were able to fit measured radial velocities of these echoes with a 6 component model that consists of horizontal winds, spatial gradients of horizontal winds and vertical wind. The conventional method of deriving horizontal winds from meteor echoes utilizes a 2 component model, assuming that vertical winds and spatial gradients of horizontal winds are negligible. We analyzed the radar data obtained for 8400 hours in 2012 and 8100 hours in 2011. We found that daily mean values of vertical winds are mostly within +/- 1 m/s, whereas those of zonal winds are a few tens m/s mostly eastward. The daily mean vertical winds sometimes stay positive or negative for more than 20 days, implying that the atmosphere near the mesopause experiences episodically a large scale low and high pressure environments, respectively, like the tropospheric weather system. By conducting Lomb-normalized periodogram analysis, we also found that the vertical winds have diurnal, semidiurnal and terdiurnal tidal components with about equal significance, in contrast to horizontal winds that show a dominant semidiurnal one. We will discuss about uncertainties of the estimated vertical wind and possible reasons of its tidal and daily variations.

  11. The measurement of oxygen in vivo using EPR techniques

    International Nuclear Information System (INIS)

    Swartz, Harold M.; Clarkson, Robert B.

    1998-01-01

    The measurement of pO 2 in vivo using EPR has some features which have already led to very useful applications and this approach is likely to have increasingly wide and effective use. It is based on the effect of oxygen on EPR spectra which provides a sensitive and accurate means to measure pO 2 quantitatively. The development of oxygen-sensitive paramagnetic materials which are very stable, combined with instrumental developments, has been crucial to the in vivo applications of this technique. The physical basis and biological applications of in vivo EPR oximetry are reviewed, with particular emphasis on the use of EPR spectroscopy at 1 GHz using particulate paramagnetic materials for the repetitive and non-invasive measurement of pO 2 in tissues. In vivo EPR has already produced some very useful results which have contributed significantly to solving important biological problems. The characteristics of EPR oximetry which appear to be especially useful are often complementary to existing techniques for measuring oxygen in tissues. These characteristics include the capability of making repeated measurements from the same site, high sensitivity to low levels of oxygen, and non-invasive options. The existing techniques are especially useful for studies in small animals, where the depth of measurements is not an overriding issue. In larger animals and potentially in human subjects, non-invasive techniques seem to be immediately applicable to study phenomena very near the surface (within 10 mm) while invasive techniques have some very promising uses. The clinical uses of EPR oximetry which seem especially promising and likely to be undertaken in the near future are long-term monitoring of the status and response to treatment of peripheral vascular disease and optimizing cancer therapy by enabling it to be modified on the basis of the pO 2 measured in the tumour. (author)

  12. Analysis of Transmitter Produced Intermodulation Interference in Colocated VHF Sites using a Microcomputer.

    Science.gov (United States)

    1986-06-01

    intermodulation product type. The notation fl will be used to represent the first frequency in the frequency list , f2 to represent the second frequency, f3... frequency list . If you entered this function by mistake, just press <RETURN> without entering a frequency to return to the EDIT MENU. A-31 .9...frequency. At this point you may step through the frequency list , edit the data, or delete a frequency. To step through the frequency list use the

  13. A new approach for extension of the identification period of irradiated cellulose-containing foodstuffs by EPR spectroscopy

    International Nuclear Information System (INIS)

    Yordanov, Nicola D.; Gancheva, Veselka

    2000-01-01

    We report on the possibility of identification by EPR spectroscopy of some irradiated cellulose-containing foodstuffs, at a relatively long time after the irradiation, when the characteristic EPR spectral lines of the cellulose free radical have essentially disappeared. In such cases rather expensive and time-consuming methods (e.g. thermoluminescence analysis) have to be applied. The present communication demonstrates with some pre-irradiated spices, dried medicinal and sweet herbs that simply heating the samples to 60 deg. C for one hour leads to a significant (50% or more) decrease of the EPR intensity of the remaining central line of the samples. For comparison, the loss in the intensity of the same line upon heating non-irradiated samples at 60 deg. C for one hour was only about 10%. This inexpensive new procedure will extend the post-irradiation period in which EPR can be used for distinguishing irradiated from non-irradiated samples, of certain cellulose-containing foodstuffs

  14. Testing and linearity calibration of films of phenol compounds exposed to thermal neutron field for EPR dosimetry.

    Science.gov (United States)

    Gallo, S; Panzeca, S; Longo, A; Altieri, S; Bentivoglio, A; Dondi, D; Marconi, R P; Protti, N; Zeffiro, A; Marrale, M

    2015-12-01

    This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was found and the signal was compared with that of commercial alanine films. Our analysis showed that gadolinium oxide (5% by weight) can enhance the thermal neutron sensitivity more than 18 times. Irradiated dosimetric films of phenolic compound exhibited EPR signal fading of about 4% after 10 days from irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Meeting the next generation PWR safety requirements: The EPR Reactor

    International Nuclear Information System (INIS)

    Salhi, Othman

    2008-01-01

    The development process pursued the harmonization of technical solutions and the integration of all the lessons learned from earlier nuclear plants built by both vendors. As far as safety more specifically is concerned, the basic choice for the EPR was to adopt an evolutionary approach based on experience feedback from the reactors built by Areva, which at the time already amounted to nearly 100. This philosophy makes today's Areva EPR the natural descendant of the most advanced French N4 and German Konvoi power reactors currently in operation. EPR design choices affecting safety were motivated by a continuous quest for higher levels of safety. A two-fold approach was followed: 1. improvement of the measures aimed at further reducing the already very low probability of core melt 2. incorporation of measures aimed at further limiting the consequences of a severe accident, in the knowledge that its probability of occurrence has been considerably reduced. Through its filiations with French N4 and German Konvoi power reactors, the EPR benefits from the uninterrupted, evolutionary innovation process that has supported the development of PWRs since their introduction into the market place. This is especially true for safety where the EPR brings a unique combination of both tried and tested and innovative features that further improve the prevention of severe accidents and their mitigation

  16. Applications of EPR steering in quantum teleportation and NOON states

    Science.gov (United States)

    Zárate, Laura Rosales

    2018-04-01

    Einstein-Podolsky-Rosen (EPR) steering refers to the type of correlations described in the EPR paradox, where one observer seems to affect ("steer") the state of other observer by using local measurements. There have been several works regarding characterization and quantification of EPR steering. One characteristic of this non-local correlation is that it can be asymmetric, while entanglement is symmetric. This asymmetric property is relevant for potential applications of EPR steering to quantum information, in particular to quantum cryptography and quantum teleportation. This latter refers to the process where one observer sends an unknown quantum state to Bob, who is in a different location. They communicate by classical means. Here we will show that EPR steering is a necessary resource to obtain secure continuous variable teleportation. We will also consider NOON states, which is an example of an entangled state. For this state, we will present a steering signature. This contribution reviews the work derived in Refs. [1] and [2], which was presented as an invited talk in ELAF 2017.

  17. Chirp echo Fourier transform EPR-detected NMR.

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  18. Chirp echo Fourier transform EPR-detected NMR

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

  19. The use of deciduous molars in EPR dose reconstruction

    International Nuclear Information System (INIS)

    El-faramawy, N.A.; Wieser, A.

    2005-01-01

    The use of deciduous teeth in EPR dose reconstruction has the unique potential to measure individual doses that were accumulated in the early childhood in the age up to 12 years. It was found previously that due to the small size of deciduous incisors, the available amount of enamel is not sufficient for EPR measurements. Therefore, dose assessment with deciduous incisors can only be done by measurement of whole teeth, including enamel and dentine. The measurement of whole teeth instead of enamel alone is possibly less reliable for dose reconstruction because the stability of CO 2 - radicals (that are an indicator for the absorbed dose) in biologically active dentine is not known. In the present study naturally loosed deciduous molars were investigated. The feasibility of separating enamel from small size molars was analysed. EPR spectrum parameters of whole molars and separated enamel only were evaluated before and after laboratory irradiation. The EPR signal amplitudes of the CO 2 - and native signals were determined by spectrum deconvolution, in dependence on radiation dose in the range 0.1 - 10 Gy. The fading at room temperature of native and CO 2 - EPR signals was analysed. The detection threshold for absorbed dose in enamel was determined.

  20. Development of a new dosimeter of EPR based on lactose

    International Nuclear Information System (INIS)

    Cruz C, L.; Torijano C, E.; Azorin N, J.; Aguirre G, F.; Cruz Z, E.

    2014-08-01

    50 years have passed since was proposed using the amino acid alanine as dosimeter advantage the phenomenon of electron paramagnetic resonance (EPR); this dosimetric method has reached a highly competitive level regarding others dosimetry classic methods, for example the thermoluminescence or the use of Fricke dosimeters, to measure high dose of radiation. In this type of materials, the free radicals induced by the radiation are stable and their concentration is proportional to the absorbed dose may be determined by the amplitude pick to pick of the first derived of the EPR absorption spectrum. The obtained results studying the EPR response of lactose tablets elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa are presented. The tablets were irradiated with gamma radiation of 60 Co in the irradiator Gamma beam 651-Pt of the Instituto de Ciencias Nucleares de la Universidad Nacional Autonoma de Mexico to a dose rate of 8 kGy-h -1 and their EPR response in a EPR spectrometer e-scan Bruker. The obtained response in function of the dose was lineal in the interval of 1 at 10 kGy. The lactose sensibility was compared with the l-alanine, used as reference, and the result was consistently 0.25 of this. Due to the linearity shown in the interval of used dose and their low production cost, we conclude that the lactose is a promissory option for the dosimetry of high dose of radiation. (author)

  1. Monitoring sequential electron transfer with EPR

    International Nuclear Information System (INIS)

    Thurnauer, M.C.; Feezel, L.L.; Snyder, S.W.; Tang, J.; Norris, J.R.; Morris, A.L.; Rustandi, R.R.

    1989-01-01

    A completely general model which treats electron spin polarization (ESP) found in a system in which radical pairs with different magnetic interactions are formed sequentially has been described. This treatment has been applied specifically to the ESP found in the bacterial reaction center. Test cases show clearly how parameters such as structure, lifetime, and magnetic interactions within the successive radical pairs affect the ESP, and demonstrate that previous treatments of this problem have been incomplete. The photosynthetic bacterial reaction center protein is an ideal system for testing the general model of ESP. The radical pair which exhibits ESP, P 870 + Q - (P 870 + is the oxidized, primary electron donor, a bacteriochlorophyll special pair and Q - is the reduced, primary quinone acceptor) is formed via sequential electron transport through the intermediary radical pair P 870 + I - (I - is the reduced, intermediary electron acceptor, a bacteriopheophytin). In addition, it is possible to experimentally vary most of the important parameters, such as the lifetime of the intermediary radical pair and the magnetic interactions in each pair. It has been shown how selective isotopic substitution ( 1 H or 2 H) on P 870 , I and Q affects the ESP of the EPR spectrum of P 870 + Q - , observed at two different microwave frequencies, in Fe 2+ -depleted bacterial reaction centers of Rhodobacter sphaeroides R26. Thus, the relative magnitudes of the magnetic properties (nuclear hyperfine and g-factor differences) which influence ESP development were varied. The results support the general model of ESP in that they suggest that the P 870 + Q - radical pair interactions are the dominant source of ESP production in 2 H bacterial reaction centers

  2. Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar

    Directory of Open Access Journals (Sweden)

    N. Swarnalingam

    2009-04-01

    Full Text Available The Resolute Bay VHF radar, located in Nunavut, Canada (75.0° N, 95.0° W and operating at 51.5 MHz, has been used to investigate Polar Mesosphere Summer Echoes (PMSE since 1997. PMSE are a unique form of strong coherent radar echoes, and their understanding has been a challenge to the scientific community since their discovery more than three decades ago. While other high latitude radars have recorded strong levels of PMSE activities, the Resolute Bay radar has observed relatively lower levels of PMSE strengths. In order to derive absolute measurements of PMSE strength at this site, a technique is developed to determine the radar efficiency using cosmic (sky noise variations along with the help of a calibrated noise source. VHF radars are only rarely calibrated, but determination of efficiency is even less common. Here we emphasize the importance of efficiency for determination of cross-section measurements. The significant advantage of this method is that it can be directly applied to any MST radar system anywhere in the world as long as the sky noise variations are known. The radar efficiencies for two on-site radars at Resolute Bay are determined. PMSE backscatter cross-section is estimated, and decade-long PMSE strength variations at this location are investigated. It was noticed that the median of the backscatter cross-section distribution remains relatively unchanged, but over the years a great level of variability occurs in the high power tail of the distribution.

  3. Comparison of continuous wave, spin echo, and rapid scan EPR of irradiated fused quartz

    International Nuclear Information System (INIS)

    Mitchell, Deborah G.; Quine, Richard W.; Tseitlin, Mark; Meyer, Virginia; Eaton, Sandra S.; Eaton, Gareth R.

    2011-01-01

    The E' defect in irradiated fused quartz has spin lattice relaxation times (T 1 ) about 100-300 μs and spin-spin relaxation times (T 2 ) up to about 200 μs, depending on the concentration of defects and other species in the sample. These long relaxation times make it difficult to record an unsaturated continuous wave (CW) electron paramagnetic resonance (EPR) signal that is free of passage effects. Signals measured at X-band (∼9.5 GHz) by three EPR methods: conventional slow-scan field-modulated EPR, rapid scan EPR, and pulsed EPR, were compared. To acquire spectra with comparable signal-to-noise, both pulsed and rapid scan EPR require less time than conventional CW EPR. Rapid scan spectroscopy does not require the high power amplifiers that are needed for pulsed EPR. The pulsed spectra, and rapid scan spectra obtained by deconvolution of the experimental data, are free of passage effects.

  4. Low-Profile Multiband and Flush-Mountable Wideband Antennas for HF/VHF and K/Ka Band Applications

    Science.gov (United States)

    Garrido Lopez, David

    This thesis introduces several novel antenna systems with extended performance capabilities achieved by either enabling multiple operation bands or by widening the bandwidth. Proposed theoretical concepts are successfully tested through simulations and experiments with excellent agreement are demonstrated. The designs developed in this thesis research are low-profile or flush mountable, enabling simple platform integration. In the HF/VHF bands, the development of a novel low-profile multiband antenna for vehicular applications is presented. Specifically, an inverted-F antenna is used as a driven element, to operate at the lowest frequency of 27 MHz, whereas two parasitic elements are built as inverted-L monopoles to enable resonances at 49 and 53 MHz. To eliminate the need for an external matching network, an offset feeding technique is used. When the antenna is mounted on a vehicle and bent to follow its profile, a very low-profile is achieved (lambda/44) while good impedance and far-field performance are maintained across all three bands. The developed antenna system is not only electrically smallest among others found in the literature, but it is easily modified for other band selections and tuning of each band can be readily achieved. Vehicular antennas are often used for high power applications, which may cause exposure of nearby individuals to possibly dangerous electromagnetic fields. To assess this hazard, the RF exposure of a vehicle's crew is discussed and an original and fast modeling approach for prediction thereof is demonstrated. The modeling approach is based on eigenmode analysis for acquiring a range of frequencies where the shielding effectiveness of a vehicle cabin is expected to be lower than average. This approach is typically much faster and requires less computational resources as compared to classical full-wave analyses. This analysis also shows that the position of an antenna system is critical and must be considered when high-power RF

  5. Loads on EPR containment after RPV failure at high pressure; Belastungen des EPR-Containments in Falle eines RDB-Versagens bei hohem Druck

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, G.

    1995-08-01

    As regards the desgin of the EPR, the general strategy is to eliminate, the vessel failure at high pressure by preventive and mitigative measures. The design proposals involved trust in the reliability of dedicated devices (relief valves) for rapid depressurization. The aim is to attain a lower pressure level at the moment of vessel failure, so that the containment is capable to cope with the blowdown impact on the pit walls and the vessel supporting structures. Nevertheless, the potential of a high-pressure failure of the vessel must be kept in mind, whatever well thought-out and reliable preventive depressurization measures might be. Therefore, the reactor pressure blowdown has been studied in order to quantify the ultimate containment load, which might support future design requirements. The calculations were performed with the LWR transient analysis thermal-hydraulics computer code REALAP5/MOD3. In previous analyses, the nodalization of the problem was based on the geometrical conditions of a typical German 1300 MW(e) NPP. In the present analysis a new input model has been used, which was based on the EPR conditions. (orig./HP)

  6. Distinctive EPR signals provide an understanding of the affinity of bis-(3-hydroxy-4-pyridinonato) copper(II) complexes for hydrophobic environments.

    Science.gov (United States)

    Rangel, Maria; Leite, Andreia; Silva, André M N; Moniz, Tânia; Nunes, Ana; Amorim, M João; Queirós, Carla; Cunha-Silva, Luís; Gameiro, Paula; Burgess, John

    2014-07-07

    In this work we report the synthesis and characterization of a set of 3-hydroxy-4-pyridinone copper(ii) complexes with variable lipophilicity. EPR spectroscopy was used to characterize the structure of copper(ii) complexes in solution, and as a tool to gain insight into solvent interactions. EPR spectra of solutions of the [CuL2] complexes recorded in different solvents reveal the presence of two copper species whose ratio depends on the nature of the solvent. Investigation of EPR spectra in the pure solvents methanol, dimethylsulfoxide, dichloromethane and their 50% (v/v) mixtures with toluene allowed the characterization of two types of copper signals (gzz = 2.30 and gzz = 2.26) whose spin-Hamiltonian parameters are consistent with solvated and non-solvated square-planar copper(ii) complexes. Regarding the potential biological application of ligands and complexes and to get insight into the partition properties in water-membrane interfaces, EPR spectra were also obtained in water-saturated octanol, an aqueous solution buffered at pH = 7.4 and liposome suspensions, for three compounds representative of different hydro-lipophilic balances. Analysis of the EPR spectra obtained in liposomes allowed establishment of the location of the complexes in the water and lipid phases. In view of the results of this work we put forward the use of EPR spectroscopy to assess the affinity of copper(ii) complexes for a hydrophobic environment and also to obtain indirect information about the lipophilicity of the ligands and similar EPR silent complexes.

  7. A Local Realistic Reconciliation of the EPR Paradox

    Science.gov (United States)

    Sanctuary, Bryan

    2014-03-01

    The exact violation of Bell's Inequalities is obtained with a local realistic model for spin. The model treats one particle that comprises a quantum ensemble and simulates the EPR data one coincidence at a time as a product state. Such a spin is represented by operators σx , iσy ,σz in its body frame rather than the usual set of σX ,σY ,σZ in the laboratory frame. This model, assumed valid in the absence of a measuring probe, contains both quantum polarizations and coherences. Each carries half the EPR correlation, but only half can be measured using coincidence techniques. The model further predicts the filter angles that maximize the spin correlation in EPR experiments.

  8. ER=EPR, GHZ, and the consistency of quantum measurements

    International Nuclear Information System (INIS)

    Susskind, Leonard

    2016-01-01

    This paper illustrates various aspects of the ER=EPR conjecture. It begins with a brief heuristic argument, using the Ryu-Takayanagi correspondence, for why entanglement between black holes implies the existence of Einstein-Rosen bridges. The main part of the paper addresses a fundamental question: Is ER=EPR consistent with the standard postulates of quantum mechanics? Naively it seems to lead to an inconsistency between observations made on entangled systems by different observers. The resolution of the paradox lies in the properties of multiple black holes, entangled in the Greenberger-Horne-Zeilinger pattern. The last part of the paper is about entanglement as a resource for quantum communication. ER=EPR provides a way to visualize protocols like quantum teleportation. In some sense teleportation takes place through the wormhole, but as usual, classical communication is necessary to complete the protocol. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Free radical EPR in delineating oil bearing zones

    International Nuclear Information System (INIS)

    Sharma, R.K.; Kumar, V.; Das, T.K.; Gundu Rao, T.K.

    1993-01-01

    Presence of naturally occurring gamma ray activity has long been detected in oil/gas wells is invariably carried out for formation evaluation. Similarly, presence of free radicals in oil bearing formations has also been known for quite sometime. Present paper deals with a systematic study of detecting these free radicals in oil wells and correlations of these with x-ray and other logs for identification of hydrocarbon bearing zones. Present study attempts to establish EPR as as inexpensive and reliable tool in comparison with gamma ray and neutron density logs recorded in exploratory oil wells. EPR studies have been carried out in an exploratory well between depth intervals 1600 m-1400 m located in south of existing producing field in Bombay Offshore region. Based on these results, an EPR log has been prepared and compared with gamma ray and neutron density logs. (author). 4 refs., 1 fig., 1 tab

  10. EPR and TL correlation in some powdered Greek white marbles

    International Nuclear Information System (INIS)

    Baieetto, Vanessa; Villeneuve, Gerard; Guibert, Pierre; Schvoerer, Max

    2000-01-01

    Thermoluminescence of white powdered marble samples, chosen to display different EPR spectra, were studied. Two peaks at 280 deg. C and 360 deg. C can be observed among the TL glow curves while the EPR spectra exhibit two signals: the A signal with g perp =2.0038 and g par =2.0024 due to the SO - 3 centre and the B one with g 1 =2.0005; g 2 =2.0001; g 3 =1.9998 due to mechanical powder reduction (drilling). Owing to heating and simultaneous experiments, a correlation have been established: the 280 deg. C TL peak is associated to the A signal and thus to the SO - 3 centre and the 360 deg. C TL peak is caused by mechanical treatment corresponding to the B EPR signal

  11. EPR and TL correlation in some powdered Greek white marbles

    Energy Technology Data Exchange (ETDEWEB)

    Baieetto, Vanessa E-mail: crpaa@montaigne.u-bordeaux.fr; Villeneuve, Gerard; Guibert, Pierre; Schvoerer, Max

    2000-02-01

    Thermoluminescence of white powdered marble samples, chosen to display different EPR spectra, were studied. Two peaks at 280 deg. C and 360 deg. C can be observed among the TL glow curves while the EPR spectra exhibit two signals: the A signal with g{sub perp}=2.0038 and g{sub par} =2.0024 due to the SO{sup -}{sub 3} centre and the B one with g{sub 1}=2.0005; g{sub 2}=2.0001; g{sub 3}=1.9998 due to mechanical powder reduction (drilling). Owing to heating and simultaneous experiments, a correlation have been established: the 280 deg. C TL peak is associated to the A signal and thus to the SO{sup -}{sub 3} centre and the 360 deg. C TL peak is caused by mechanical treatment corresponding to the B EPR signal.

  12. EPR and TL correlation in some powdered Greek white marbles.

    Science.gov (United States)

    Baïetto, V; Villeneuve, G; Guibert, P; Schvoerer, M

    2000-02-01

    Thermoluminescence of white powdered marble samples, chosen to display different EPR spectra, were studied. Two peaks at 280 degrees C and 360 degrees C can be observed among the TL glow curves while the EPR spectra exhibit two signals: the A signal with g perpendicular = 2.0038 and g parallel = 2.0024 due to the SO3- centre and the B one with g1 = 2.0005; g2 = 2.0001; g3 = 1.9998 due to mechanical powder reduction (drilling). Owing to heating and simultaneous experiments, a correlation have been established: the 280 degrees C TL peak is associated to the A signal and thus to the SO3- centre and the 360 degrees C TL peak is caused by mechanical treatment corresponding to the B EPR signal.

  13. A High Sensitivity EPR Technique for Alanine Dosimetry (invited paper)

    International Nuclear Information System (INIS)

    Haskell, E.H.; Hayes, R.B.; Kenner, G.H.

    1998-01-01

    Uncertainties of ± 5 mGy were achieved in the measurement of alanine dosemeters using optimised EPR parameters, instrumentation, spectral manipulation and subtraction techniques. Modulation amplitude and microwave power were adjusted to combine resonances of two neighbouring alanine signals. Instrumental variations were minimised by combining and subtracting pre- and post-measurement spectra of the empty EPR tube. A spectrum of the native signal of non-dosed alanine was generated from a single batch of dosemeters and subtracted from spectra of the irradiated dosemeters, also from the same batch. Field alignment was adjusted with the use of an in-cavity Mn ++ standard. A constant rotation goniometer was used to eliminate anisotropies in the EPR tube and alanine samples. Finally, digital filters were applied to the resulting spectra. (author)

  14. Study of growth of polyaniline chain by EPR method

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, A V [Inst. of Chemical Physics, Chernogolovka (Russian Federation); Kogan, Ya L [Inst. of Chemical Physics, Chernogolovka (Russian Federation); Fokeeva, L S [Inst. of Chemical Physics, Chernogolovka (Russian Federation)

    1993-03-22

    Chemical aniline polymerization has been studied by the EPR method. After a long delay a weak EPR signal I is appeared and transformed rapidly into a strong Lorentzian line. Constants of spin exchange of signals I and II with paramagnetic probes Fe(CN)[sub 6][sup 3-], Co[sup 2+] and O[sub 2], freely diffusing in solution, have been determined. Effect of ferricyanide ions and urea, a breaker of hydrogen bonds, has been measured for signals I and II. Data obtained show the formation of an array of positive charges in PANI at early stage of doping. Constants of spin exchange depend on prehistory of samples. Averaging of EPR line widths of different paramagnetic centers in polyaniline was found. (orig.)

  15. ER=EPR, GHZ, and the consistency of quantum measurements

    Energy Technology Data Exchange (ETDEWEB)

    Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA (United States)

    2016-01-15

    This paper illustrates various aspects of the ER=EPR conjecture. It begins with a brief heuristic argument, using the Ryu-Takayanagi correspondence, for why entanglement between black holes implies the existence of Einstein-Rosen bridges. The main part of the paper addresses a fundamental question: Is ER=EPR consistent with the standard postulates of quantum mechanics? Naively it seems to lead to an inconsistency between observations made on entangled systems by different observers. The resolution of the paradox lies in the properties of multiple black holes, entangled in the Greenberger-Horne-Zeilinger pattern. The last part of the paper is about entanglement as a resource for quantum communication. ER=EPR provides a way to visualize protocols like quantum teleportation. In some sense teleportation takes place through the wormhole, but as usual, classical communication is necessary to complete the protocol. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Orientation-dependent effects of EPR-measurements on β-rhombohedral boron

    International Nuclear Information System (INIS)

    Siems, C.D.; Geist, D.

    1976-01-01

    EPR studies on β-rhombohedral boron have been reported by several authors. Two EPR-lines with the same g-value have been found by measurements with and without illumination. The microwave frequency used was 9 GHz, as far as is known. In this paper EPR-measurements at 35 GHz on β-rhombohedral boron single crystals are reported. The investigations concerning the 'dark EPR-line' were made at 300 K. (Auth.)

  17. The EPR - technology for the 3rd millennium

    International Nuclear Information System (INIS)

    Bernstrauch, O.; Dubois, F.

    2001-01-01

    This paper is a story of a successful Franco-German co-operation: the EPR project. It is a rundown of the history of the EPR, before a decision is made to launch the lead-unit construction. The EPR is expected to progressively replace the existing nuclear power plants when they will reach the end of their service life. It integrates the latest technological advances, especially in safety and operational aspects and comprises more than 30 years operating experience. Thus, the EPR combines the qualities of its predecessors, the French N4 and the German Konvoi. The safety of the EPR was maximized both to prevent hypothetical accidents - even severe ones - and to reduce their consequences (corium spreading area, pre-stressed double containment with local liner, four-train safety systems...). The n+2 strategy (in the event of a problem with one train and even if a second train is undergoing maintenance, the remaining two are sufficient to perform the function) allows to perform maintenance during operation which leads consequently to short outage periods, highest availabilities and economical operation. Moreover, most of the EPR components are the result of mastered evolution. The reactor vessel, as a key element for the reactor service life, is designed to be in service for 60 years, the core is large (241 fuel elements instead of 205 in the N4 or 193 in the Konvoi) and the steam generators have higher efficiency. Along the same line, the core and core barrel design have been modified to allow a reduced uranium enrichment and the increase to 65 Gigawatt-day per metric-ton of the fuel discharge burn-up. Finally, the instrumentation and control systems minimize human error by giving the operators a grace period of at least 30 minutes to make decisions. (authors)

  18. Free-radical probes for functional in vivo EPR imaging

    Science.gov (United States)

    Subramanian, S.; Krishna, M. C.

    2007-02-01

    Electron paramagnetic resonance imaging (EPRI) is one of the recent functional imaging modalities that can provide valuable in vivo physiological information on its own merit and aids as a complimentary imaging technique to MRI and PET of tissues especially with respect to in vivo pO II (oxygen partial pressure), redox status and pharmacology. EPR imaging mainly deals with the measurement of distribution and in vivo dynamics and redox changes using special nontoxic paramagnetic spin probes that can be infused into the object of investigation. These spin probes should be characterized by simple EPR spectra, preferably with narrow EPR lines. The line width should be reversibly sensitive to the concentration of in vivo pO II with a linear dependence. Several non-toxic paramagnetic probes, some particulate and insoluble and others water-soluble and infusible (by intravenous or intramuscular injection) have been developed which can be effectively used to quantitatively assess tissue redox status, and tumor hypoxia. Quantitative assessment of the redox status of tissue in vivo is important in investigating oxidative stress, and that of tissue pO II is very important in radiation oncology. Other areas in which EPR imaging and oxymetry may help are in the investigation of tumorangiogenesis, wound healing, oxygenation of tumor tissue by the ingestion of oxygen-rich gases, etc. The correct choice of the spin probe will depend on the modality of measurement (whether by CW or time-domain EPR imaging) and the particular physiology interrogated. Examples of the available spin probes and some EPR imaging applications employing them are presented.

  19. Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy.

    Science.gov (United States)

    Ishara Silva, K; Jagannathan, Bharat; Golbeck, John H; Lakshmi, K V

    2016-05-01

    Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016. Published by Elsevier B.V.

  20. A secure effective dynamic group password-based authenticated key agreement scheme for the integrated EPR information system

    Directory of Open Access Journals (Sweden)

    Vanga Odelu

    2016-01-01

    Full Text Available With the rapid growth of the Internet, a lot of electronic patient records (EPRs have been developed for e-medicine systems. The security and privacy issues of EPRs are important for the patients in order to understand how the hospitals control the use of their personal information, such as name, address, e-mail, medical records, etc. of a particular patient. Recently, Lee et al. proposed a simple group password-based authenticated key agreement protocol for the integrated EPR information system (SGPAKE. However, in this paper, we show that Lee et al.’s protocol is vulnerable to the off-line weak password guessing attack and as a result, their scheme does not provide users’ privacy. To withstand this security weakness found in Lee et al.’s scheme, we aim to propose an effective dynamic group password-based authenticated key exchange scheme for the integrated EPR information system, which retains the original merits of Lee et al.’s scheme. Through the informal and formal security analysis, we show that our scheme provides users’ privacy, perfect forward security and known-key security, and also protects online and offline password guessing attacks. Furthermore, our scheme efficiently supports the dynamic group password-based authenticated key agreement for the integrated EPR information system. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool and show that our scheme is secure against passive and active attacks.

  1. On Aerts' overlooked solution to the EPR paradox

    OpenAIRE

    de Bianchi, Massimiliano Sassoli

    2018-01-01

    The Einstein-Podolsky-Rosen (EPR) paradox was enunciated in 1935 and since then it has made a lot of ink flow. Being a subtle result, it has also been largely misunderstood. Indeed, if questioned about its solution, many physicists will still affirm today that the paradox has been solved by the Bell-test experimental results, which have shown that entangled states are real. However, this remains a wrong view, as the validity of the EPR ex-absurdum reasoning is independent from the Bell-test e...

  2. EPR of VHal centres in SrS

    International Nuclear Information System (INIS)

    Seeman, V.; Danilkin, M.; Must, M.; Ots, A.; Paernoja, E.; Pung, L.; Tarkpea, K.

    2006-01-01

    V Hal centres were studied by EPR in SrS doped with halogens after X-raying the samples at 77 K. V Hal centre arises when a hole is captured by sulphide-ion next to a cation vacancy with a halogen ion substituting the opposite sulphide-ion. EPR parameters and thermal decay characteristics are measured for V Cl , V Br , and V I centres. The efficiency of different halogens to produce and stabilise cation vacancies is shown to vary for different alkaline earth sulphides. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Bell's theorem based on a generalized EPR criterion of reality

    International Nuclear Information System (INIS)

    Eberhard, P.H.; Rosselet, P.

    1995-01-01

    First, the demonstration of Bell's theorem, i.e., of the nonlocal character of quantum theory, is spelled out using the EPR criterion of reality as premises and a gedanken experiment involving two particles. Then, the EPR criterion is extended to include quantities predicted almost with certainty, and Bell's theorem is demonstrated on these new premises. The same experiment is used but in conditions that become possible in real life, without the requirements of ideal efficiencies and zero background. Very high efficiencies and low background are needed, but these requirements may be met in the future

  4. EPR studies of gamma-irradiated taurine single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Bulut, A. E-mail: abulut@samsun.omu.edu.tr; Karabulut, B.; Tapramaz, R.; Koeksal, F

    2000-04-01

    An EPR study of gamma-irradiated taurine [C{sub 2}H{sub 7}NO{sub 3}S] single crystal was carried out at room temperature. The EPR spectra were recorded in the three at mutually perpendicular planes. There are two magnetically distinct sites in monoclinic lattice. The principle values of g and hyperfine constants for both sites were calculated. The results have indicated the presence of {sup 32}SO{sup -}{sub 2} and {sup 33}SO{sup -}{sub 2} radicals. The hyperfine values of {sup 33}SO{sup -}{sub 2} radical were used to obtain O-S-O bond angle for both sites.

  5. EPR of defects in semiconductors: past, present, future

    International Nuclear Information System (INIS)

    Watkins, G.D.

    1999-01-01

    Important physical concepts learned from early EPR studies of defects in silicon are reviewed. Highlighted are the studies of shallow effective-mass-liked donors and acceptors of deep transition element impurities, and of vacancies and interstitials. It is shown that the concepts learned in silicon translate remarkable well to the corresponding defects in the other elemental and compound semiconductors. The introduction of sensitive optical and electrical detection methods and the recent progress in single defects detection insure the continued vital role of EPR in the future

  6. EPR studies of gamma-irradiated taurine single crystals

    International Nuclear Information System (INIS)

    Bulut, A.; Karabulut, B.; Tapramaz, R.; Koeksal, F.

    2000-01-01

    An EPR study of gamma-irradiated taurine [C 2 H 7 NO 3 S] single crystal was carried out at room temperature. The EPR spectra were recorded in the three at mutually perpendicular planes. There are two magnetically distinct sites in monoclinic lattice. The principle values of g and hyperfine constants for both sites were calculated. The results have indicated the presence of 32 SO - 2 and 33 SO - 2 radicals. The hyperfine values of 33 SO - 2 radical were used to obtain O-S-O bond angle for both sites

  7. The inner containment of an EPR trademark pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ostermann, Dirk; Krumb, Christian; Wienand, Burkhard [AREVA GmbH, Offenbach (Germany)

    2014-08-15

    On February 12, 2014 the containment pressure and subsequent leak tightness tests on the containment of the Finnish Olkiluoto 3 EPR trademark reactor building were completed successfully. The containment of an EPR trademark pressurized water reactor consists of an outer containment to protect the reactor building against external hazards (such as airplane crash) and of an inner containment that is subjected to internal overpressure and high temperature in case of internal accidents. The current paper gives an overview of the containment structure, the design criteria, the validation by analyses and experiments and the containment pressure test.

  8. Bell's theorem based on a generalized EPR criterion of reality

    International Nuclear Information System (INIS)

    Eberhard, P.H.; Rosselet, P.

    1993-04-01

    First, the demonstration of Bell's theorem, i.e. of the non-local character of quantum theory, is spelled out using the EPR criterion of reality as premises and a gedanken experiment involving two particles. Then, the EPR criterion is extended to include quantities predicted almost with certainty, and Bell's theorem is demonstrated on these new premises. The same experiment is used but in conditions that become possible in real life, without the requirements of ideal efficiencies and zero background. Very high efficiencies and low background are needed, but these requirements may be met in the future. (author) 1 fig., 11 refs

  9. Nuclear choice. Towards the EPR with mincing steps

    International Nuclear Information System (INIS)

    Jemain, A.

    2003-01-01

    The French government is on the way to give its green light for the construction of the EPR (European Pressurized water Reactor), the 1600 MWe demonstrator reactor of third generation of Framatome ANP (Areva). Fifty seven months will be necessary for its construction which, with the public inquiry, would lead to a first commissioning by 2010. This reactor will progressively renew the present day park between 2015-2020. The EPR project will cost 3 billions of euros but the financing remains to be found. Short paper. (J.S.)

  10. 75 FR 4882 - Meeting of the ACRS Subcommittee on EPR; Notice of Meeting

    Science.gov (United States)

    2010-01-29

    ... NUCLEAR REGULATORY COMMISSION Advisory Committee On Reactor Safeguards (ACRS) Meeting of the ACRS Subcommittee on EPR; Notice of Meeting The ACRS U.S. Evolutionary Power Reactor (EPR) Subcommittee will hold a... with Open Items concerning the U.S. EPR Design Certification (DCD) Application and the Calvert Cliffs...

  11. High-frequency EPR on high-spin transition-metal sites

    NARCIS (Netherlands)

    Mathies, Guinevere

    2012-01-01

    The electronic structure of transition-metal sites can be probed by electron-paramagnetic-resonance (EPR) spectroscopy. The study of high-spin transition-metal sites benefits from EPR spectroscopy at frequencies higher than the standard 9.5 GHz. However, high-frequency EPR is a developing field. In

  12. Application of BAT assessments for sampling and monitoring techniques in the UK EPR

    International Nuclear Information System (INIS)

    Kerdaniel, Erwan du Fou de; Colin, Julie; Moyano, Florian; Ardon, Audrey

    2014-01-01

    EDF Energy intends to build two EPR units at the Hinkley Point C site and has initiated the studies to build two more EPR units at Sizewell C. The project is lead by NNB GenCo, a subsidiary of EDF Energy. NNB GenCo, identified as the future operator and intelligent customer, relies upon EDF SA's expertise as responsible designer. UK EPR design substantiation has been carried out during the Generic Design Assessment (GDA), with two key reports, namely the Pre-Construction Environmental Report and the Pre-Construction Safety Report. These reports lead to specific enquiries initiated by the Regulators through 'Assessment Findings' in all areas, including Chemistry. Along the GDA process, the Environmental Agency (EA) has authorised chemical and radiochemical effluents discharges, requiring NNB GenCo to demonstrate that Best Available Techniques (BAT) are used to sample and monitor the discharges and the generation of solid wastes. BAT demonstrations deliverables are formalised via 'Commitment Plans' and detailed within 'Environmental Optimisation Studies (EOS)' reports, in line with NNB GenCo's management arrangements. NNB GenCo manages the production of the EOS reports. EDF CEIDRE Laboratory department (CEIDRE/DLAB) has been identified as a contributor to the BAT demonstration regarding sampling and monitoring of chemical effluents, active effluents and solid wastes. As required by the definition of BAT in the UK context, demonstrations are based on: UK Regulatory context and associated specific requirements, International feedback analysis of European, EPRI and IAEA documents, French fleet framework: benchmarks with the operator, analysis of technical and operational management documentation, Sizewell B framework: benchmarks with the operator, analysis of technical and operational management documents, International, British and French standards. A close partnership between the different EDF SA departments and a clear

  13. EPR/alanine dosimetry for two therapeutic proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, Maurizio, E-mail: maurizio.marrale@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Carlino, Antonio [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700 Wiener Neustadt (Austria); Gallo, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Laboratorio PH3DRA, Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); Longo, Anna; Panzeca, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony [Center for Proton Therapy, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2016-02-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  14. EPR/alanine dosimetry for two therapeutic proton beams

    International Nuclear Information System (INIS)

    Marrale, Maurizio; Carlino, Antonio; Gallo, Salvatore; Longo, Anna; Panzeca, Salvatore; Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony

    2016-01-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  15. High-Rate Fabrication of a-Si-Based Thin-Film Solar Cells Using Large-Area VHF PECVD Processes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Xunming [University of Toledo; Fan, Qi Hua

    2011-12-31

    The University of Toledo (UT), working in concert with it’s a-Si-based PV industry partner Xunlight Corporation (Xunlight), has conducted a comprehensive study to develop a large-area (3ft x 3ft) VHF PECVD system for high rate uniform fabrication of silicon absorber layers, and the large-area VHF PECVD processes to achieve high performance a-Si/a-SiGe or a-Si/nc-Si tandem junction solar cells during the period of July 1, 2008 to Dec. 31, 2011, under DOE Award No. DE-FG36-08GO18073. The project had two primary goals: (i) to develop and improve a large area (3 ft × 3 ft) VHF PECVD system for high rate fabrication of > = 8 Å/s a-Si and >= 20 Å/s nc-Si or 4 Å/s a-SiGe absorber layers with high uniformity in film thicknesses and in material structures. (ii) to develop and optimize the large-area VHF PECVD processes to achieve high-performance a-Si/nc-Si or a-Si/a-SiGe tandem-junction solar cells with >= 10% stable efficiency. Our work has met the goals and is summarized in “Accomplishments versus goals and objectives”.

  16. Chameleon Effect, the Range of Values Hypothesis and Reproducing the EPR-Bohm Correlations

    Science.gov (United States)

    Accardi, Luigi; Khrennikov, Andrei

    2007-02-01

    We present a detailed analysis of assumptions that J. Bell used to show that local realism contradicts QM. We find that Bell's viewpoint on realism is nonphysical, because it implicitly assume that observed physical variables coincides with ontic variables (i.e., these variables before measurement). The real physical process of measurement is a process of dynamical interaction between a system and a measurement device. Therefore one should check the adequacy of QM not to "Bell's realism," but to adaptive realism (chameleon realism). Dropping Bell's assumption we are able to construct a natural representation of the EPR-Bohm correlations in the local (adaptive) realistic approach.

  17. Kinetics of elimination and distribution in blood and liver of biocompatible ferrofluids based on Fe{sub 3}O{sub 4} nanoparticles: An EPR and XRF study

    Energy Technology Data Exchange (ETDEWEB)

    Gamarra, L.F. [Instituto de Ensino e Pesquisa, Hospital Israelita Albert Einstein, Sao Paulo 05651-901 (Brazil); Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo 05315-970 (Brazil)], E-mail: lgamarra@if.usp.br; Pontuschka, W.M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo 05315-970 (Brazil); Amaro, E. [Instituto de Ensino e Pesquisa, Hospital Israelita Albert Einstein, Sao Paulo 05651-901 (Brazil); Instituto de Radiologia, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 05403-001 (Brazil); Costa-Filho, A.J. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos 13560-970 (Brazil); Brito, G.E.S. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo 05315-970 (Brazil); Vieira, E.D. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos 13560-970 (Brazil); Carneiro, S.M. [Laboratorio de Biologia Celular, Instituto Butantan, Sao Paulo 05503-900 (Brazil); Escriba, D.M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo 05315-970 (Brazil); Falleiros, A.M.F. [Centro de Ciencias Biologicas, Universidade Estadual de Londrina 86051-990 (Brazil); Salvador, V.L. [Centro de aplicacoes e Lasers, IPEN, Sao Paulo 05508-000 (Brazil)

    2008-05-01

    In this study, we evaluated the biodistribution and the elimination kinetics of a biocompatible magnetic fluid, Endorem{sup TM}, based on dextran-coated Fe{sub 3}O{sub 4} nanoparticles endovenously injected into Winstar rats. The iron content in blood and liver samples was recorded using electron paramagnetic resonance (EPR) and X-ray fluorescence (XRF) techniques. The EPR line intensity at g = 2.1 was found to be proportional to the concentration of magnetic nanoparticles and the best temperature for spectra acquisition was 298 K. Both EPR and XRF analysis indicated that the maximum concentration of iron in the liver occurred 95 min after the ferrofluid administration. The half-life of the magnetic nanoparticles (MNP) in the blood was (11.6 {+-} 0.6) min measured by EPR and (12.6 {+-} 0.6) min determined by XRF. These results indicate that both EPR and XRF are very useful and appropriate techniques for the study of kinetics of ferrofluid elimination and biodistribution after its administration into the organism.

  18. Kinetics of elimination and distribution in blood and liver of biocompatible ferrofluids based on Fe3O4 nanoparticles: An EPR and XRF study

    International Nuclear Information System (INIS)

    Gamarra, L.F.; Pontuschka, W.M.; Amaro, E.; Costa-Filho, A.J.; Brito, G.E.S.; Vieira, E.D.; Carneiro, S.M.; Escriba, D.M.; Falleiros, A.M.F.; Salvador, V.L.

    2008-01-01

    In this study, we evaluated the biodistribution and the elimination kinetics of a biocompatible magnetic fluid, Endorem TM , based on dextran-coated Fe 3 O 4 nanoparticles endovenously injected into Winstar rats. The iron content in blood and liver samples was recorded using electron paramagnetic resonance (EPR) and X-ray fluorescence (XRF) techniques. The EPR line intensity at g = 2.1 was found to be proportional to the concentration of magnetic nanoparticles and the best temperature for spectra acquisition was 298 K. Both EPR and XRF analysis indicated that the maximum concentration of iron in the liver occurred 95 min after the ferrofluid administration. The half-life of the magnetic nanoparticles (MNP) in the blood was (11.6 ± 0.6) min measured by EPR and (12.6 ± 0.6) min determined by XRF. These results indicate that both EPR and XRF are very useful and appropriate techniques for the study of kinetics of ferrofluid elimination and biodistribution after its administration into the organism

  19. EPR of gamma irradiated solid sucrose and UV spectra of its solution. An attempt for calibration of solid state/EPR dosimetry

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Karakirova, Y.

    2007-01-01

    A simple new approach for independent calibration of solid state/EPR (SS/EPR) dosimetry system is reported. It is based on the fact that: (i) gamma-irradiation of solid sucrose (sugar) induces stable EPR detectable free radicals accompanied by UV detectable brown colour stable in the solid state and in solution; (ii) both the EPR intensity of gamma-irradiated solid sucrose and its solution UV absorbance linearly depend on the absorbed dose high energy radiation and may be independently used for dosimetric purpose; (iii) UV spectrometers are calibrated. The correlation between EPR response and absorbed dose radiation of solid sucrose and UV absorption of its solutions is used in the present communication for calibration purpose. The procedure of sucrose extraction from sucrose-paraffin dosimeters is described. The calibration procedure may be applied to any other (alanine, self-calibrated, etc.) SS/EPR dosimeters, simultaneously irradiated with sucrose

  20. Utilizing Yagi antennas in Lightning Mapping Array to detect low-power VHF signals

    Science.gov (United States)

    Tilles, J.; Thomas, R. J.; Edens, H. E.; Krehbiel, P. R.; Rison, W.

    2013-12-01

    The New Mexico Tech VHF Lightning Mapping Array (LMA) being operated at Langmuir Laboratory in central New Mexico is comprised of 22 time-of-arrival stations spanning an area approximately 60 km north-south and 45 km east-west. Nine stations are at high altitude (3.1-3.3 km GPS) over a 3 x 4 km area around the mountain-top Laboratory, and 13 are on the surrounding plains and the Rio Grande valley, at altitudes between 1.4 and 2.2 km. Each station utilizes a vertical half-wave dipole antenna having about 2 dBi gain at horizontal incidence and providing omnidirectional azimuthal coverage. In 2012, four additional stations utilizing higher gain (11 dBi) Yagi antennas were co-located at four of the surrounding sites within 10-15 km of the laboratory, each pointed over the laboratory area. The purpose was to test if directional antennas would improve detection of low-power sources in the laboratory vicinity, such as those associated with positive breakdown or weak precursor events. The test involved comparing the number and quality of radiation sources obtained by processing data from two sets of stations: first for a 17-station network in which all stations were omnidirectional, and then for the same network with Yagi-based measurements substituted in place of the omni measurements at the four co-located stations. For radiation events located in both datasets, the indicated source power values from Yagi stations were typically 5-10 dB greater than their omnidirectional counterpart for sources over or near the laboratory, consistent with the 9 dB difference in on-axis gain values. The difference decreased through zero and to negative values with increasing distance from the laboratory, confirming that it was due to the directionality of the Yagi antennas. It was expected that a network having Yagi antennas at all outlying stations would improve the network's detection of lower power sources in its central region. Rather, preliminary results show that there is no

  1. Stability of cellulose radicals produced by radiation in spices as studied by the EPR spectroscopy

    International Nuclear Information System (INIS)

    Lehner, K.; Stachowicz, W.

    2003-01-01

    The results are presented of EPR measurements on the stability of cellulose radicals produced in 26 popular spices irradiated with a dose of 7 kGy of gamma rays. EPR measurements were done with the use of an EPR spectrometer EPR-10 MINI at X band (microwave radiation of frequency 9.5 GHz), produced by St. Petersburg Instruments Ltd. The aim of the work was to prove the applicability of the EPR method for the control of irradiation in the investigated spices. (author)

  2. Interpretation of the parameters of the EPR spectra of transition metal complexes

    International Nuclear Information System (INIS)

    Murav'ev, V.I.

    2005-01-01

    The calculated parameters of the EPR spectra of complexes of d 1 and d 9 ions, inclusive of MoOX 5 (X = Cl, Br), are reviewed. The covalent bond parameters used in the calculations were determined from EPR and experimental optical data (inverse problem of EPR spectroscopy). Various contributions to the expressions for the EPR parameters were compared. The observed abnormal values of the EPR parameters were discussed. The effects of charge-transfer states and the vibronic coupling on the components of g, A, and A L tensors were considered. Mechanisms of spin density transfer to ligands in paramagnetic complexes were proposed [ru

  3. Electrical transport and EPR investigations: A comparative study for ...

    Indian Academy of Sciences (India)

    did not have relatively such a high conductivity, skin depth was expected to be more than 1 μm. On the basis of g-values, line width, line shape behaviour and earlier observations by other researchers (Lux 1994;. Luthra et al 2003; Krinichnyi et al 2006), the EPR signal obtained has been assigned due to polarons (Bredas.

  4. Antioxidant Capacity: Experimental Determination by EPR Spectroscopy and Mathematical Modeling.

    Science.gov (United States)

    Polak, Justyna; Bartoszek, Mariola; Chorążewski, Mirosław

    2015-07-22

    A new method of determining antioxidant capacity based on a mathematical model is presented in this paper. The model was fitted to 1000 data points of electron paramagnetic resonance (EPR) spectroscopy measurements of various food product samples such as tea, wine, juice, and herbs with Trolox equivalent antioxidant capacity (TEAC) values from 20 to 2000 μmol TE/100 mL. The proposed mathematical equation allows for a determination of TEAC of food products based on a single EPR spectroscopy measurement. The model was tested on the basis of 80 EPR spectroscopy measurements of herbs, tea, coffee, and juice samples. The proposed model works for both strong and weak antioxidants (TEAC values from 21 to 2347 μmol TE/100 mL). The determination coefficient between TEAC values obtained experimentally and TEAC values calculated with proposed mathematical equation was found to be R(2) = 0.98. Therefore, the proposed new method of TEAC determination based on a mathematical model is a good alternative to the standard EPR method due to its being fast, accurate, inexpensive, and simple to perform.

  5. Isothermal annealing kinetics of X-irradiated pyrene by EPR

    International Nuclear Information System (INIS)

    Partiti, C.S.M.; Pontuschka, W.M.; Fazzio, A.; Piccini, A.

    1989-07-01

    The annealing behavior of X-irradiated stable free radicals found in Pyrene (C 16 H 10 ) single crystals was studied by EPR. Two processes of thermal decay kinetics were found, both with the same activation energy (1.9±0.1) ev. (author) [pt

  6. SWNT probed by multi-frequency EPR and microwave absorption

    NARCIS (Netherlands)

    Corzilius, B.; Dinse, K.P.; Hata, K.; Haluska, M.; Skakalova, V.; Roth, S.

    2008-01-01

    In addition to g = 2.00 signals seen frequently in EPR spectra of SWNT, signals at g = 2.07 of SWNT prepared by CVD were detected, exhibiting a Pauli susceptibility temperature dependence. This Pauli magnetism in combination with the large g shift is taken as evidence that these signals originate

  7. Noninvasive in vivo oximetric imaging by radiofrequency FT EPR

    NARCIS (Netherlands)

    Subramanian, S; Yamada, K; Irie, A; Murugesan, R; Cook, JA; Devasahayam, N; Van Dam, GM; Mitchell, JB; Krishna, MC

    A novel method, called relaxo-oximetry, for rapid spatially resolved in vivo measurements of oxygen concentration using time-domain radiofrequency (RF) electron paramagnetic resonance (EPR) is described. Time-domain data from triaryl methyl (TAM)-based single-electron contrast agents were processed

  8. Joint probabilities reproducing three EPR experiments on two qubits

    NARCIS (Netherlands)

    Roy, S. M.; Atkinson, D.; Auberson, G.; Mahoux, G.; Singh, V.

    2007-01-01

    An eight-parameter family of the most general non-negative quadruple probabilities is constructed for EPR-Bohm-Aharonov experiments when only three pairs of analyser settings are used. It is a simultaneous representation of three different Bohr-incompatible experimental configurations involving

  9. The EPR Paradox: Einstein Scrutinises Quantum Mechanics -28 ...

    Indian Academy of Sciences (India)

    Arvind. Einstein, Podolsky and Rosen (EPR), in their fa- mous paper, argued that the quantum-mechani- cal description of physical reality is incomplete. They showed that one can envisage physical sit- uations whereby 'an element of physical reality' can be located such that it does not have a coun- terpart in quantum ...

  10. Current status of the EPR method to detect irradiated food

    International Nuclear Information System (INIS)

    Desrosiers, M.F.

    1996-01-01

    This review gives a brief outline of the principles of the EPR detection method for irradiated foods by food type. For each food type, the scope, limitations and status of the method are given. The extensive reference list aims to include all which define the method, as well as some rarely cited works of historical importance. (author)

  11. Deconvolution of EPR spectral lines with an approximate method

    International Nuclear Information System (INIS)

    Jimenez D, H.; Cabral P, A.

    1990-10-01

    A recently reported approximation expression to deconvolution Lorentzian-Gaussian spectral lines. with small Gaussian contribution, is applied to study an EPR line shape. The potassium-ammonium solution line reported in the literature by other authors was used and the results are compared with those obtained by employing a precise method. (Author)

  12. Spo0A positively regulates epr expression by negating the ...

    Indian Academy of Sciences (India)

    2013-03-07

    Mar 7, 2013 ... ly regulate the epr expression by the process of co-repression. (Kodgire et al. 2006). ... Bacterial strains and plasmids used in this study are listed in table 1. E. coli DH5α ... Wherever necessary, antibiotics were added to the ...

  13. Water-resistant alanine-EPR dosimeter alanpol

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Zofia; Bryl-Sandelewska, Teresa; Mirkowski, Krzysztof; Sartowska, Bozena

    2009-01-01

    Alanpol-water-resistant alanine-electron paramagnetic resonance (EPR) dosimeter consisted of cheap DL-α-alanine (9.8-27%) suspended in polyethylene matrix was presented. The rods (O=2.8 mm) were extruded from a hot mixture of alanine and low-density polyethylene. No grinding or crushing was used for alanine preparation. An orientation of cylindrical crystals, up to 300 μm long in parallel to the rod axis was responsible for some differences in a shape of EPR signal. These differences had no negative consequences for dosimetric applications. Signal-to-dose dependence was linear up to 10 kGy. Standard deviation of dosimetric answer was up to ±1.8% and up to 2.4% for dosimeters with 9.8% and 27% of DL-α-alanine, respectively. Irradiation temperature coefficient for both dosimeters was equal 0.2%/ deg. C. Hydrophobic properties of polyethylene and small number of alanine crystals located on the surface of the rod led to high resistance of dosimeters to water and humidity. The 24 h soaking of irradiated dosimeters in liquid water-reduced EPR signals by 3-4% and by 2-3% for dosimeters with 27% and 9.8% of DL-α-alanine, respectively. Three month storage time of irradiated dosimeters in room conditions decreases EPR signal for ∼3%.

  14. EPR Imaging at a Few Megahertz Using SQUID Detectors

    Science.gov (United States)

    Hahn, Inseob; Day, Peter; Penanen, Konstantin; Eom, Byeong Ho

    2010-01-01

    An apparatus being developed for electron paramagnetic resonance (EPR) imaging operates in the resonance-frequency range of about 1 to 2 MHz well below the microwave frequencies used in conventional EPR. Until now, in order to obtain sufficient signal-to-noise radios (SNRs) in conventional EPR, it has been necessary to place both detectors and objects to be imaged inside resonant microwave cavities. EPR imaging has much in common with magnetic resonance imaging (MRI), which is described briefly in the immediately preceding article. In EPR imaging as in MRI, one applies a magnetic pulse to make magnetic moments (in this case, of electrons) precess in an applied magnetic field having a known gradient. The magnetic moments precess at a resonance frequency proportional to the strength of the local magnetic field. One detects the decaying resonance-frequency magnetic- field component associated with the precession. Position is encoded by use of the known relationship between the resonance frequency and the position dependence of the magnetic field. EPR imaging has recently been recognized as an important tool for non-invasive, in vivo imaging of free radicals and reduction/oxidization metabolism. However, for in vivo EPR imaging of humans and large animals, the conventional approach is not suitable because (1) it is difficult to design and construct resonant cavities large enough and having the required shapes; (2) motion, including respiration and heartbeat, can alter the resonance frequency; and (3) most microwave energy is absorbed in the first few centimeters of tissue depth, thereby potentially endangering the subject and making it impossible to obtain adequate signal strength for imaging at greater depth. To obtain greater penetration depth, prevent injury to the subject, and avoid the difficulties associated with resonant cavities, it is necessary to use lower resonance frequencies. An additional advantage of using lower resonance frequencies is that one can use

  15. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimitrova, A. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Georgieva, L. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Tzvetkova, E. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria)

    2006-09-15

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030+/-0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50days, an asymmetric singlet EPR line with g=2.0041+/-0.0005. Only apricot pulp gave a typical ''sugar-like'' EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g{sub ||}=2.0023+/-0.0003 and g{sub -}bar =2.0041+/-0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn{sup 2+} naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  16. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Science.gov (United States)

    Yordanov, N. D.; Aleksieva, K.; Dimitrova, A.; Georgieva, L.; Tzvetkova, E.

    2006-09-01

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030±0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50 days, an asymmetric singlet EPR line with g=2.0041±0.0005. Only apricot pulp gave a typical "sugar-like" EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g=2.0023±0.0003 and g⊥=2.0041±0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn 2+ naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  17. Theoretical investigations of the optical and EPR spectra for trivalent cerium and ytterbium ions in orthorhombic YF{sub 3} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong-Gang, E-mail: kezhouliu@163.com; Zheng, Wen-Chen

    2016-09-01

    The optical spectra and electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants A) for trivalent cerium and ytterbium ions in YF{sub 3} crystal with orthorhombic structure are investigated together by the complete diagonalization (of energy matrix) method (CDM). The obtained results are in reasonable agreement with the experimental ones. More importantly, two magnetically nonequivalent centers in YF{sub 3} crystal observed in EPR experiments are confirmed and ascribed to their specific positions in a unit cell by our calculations based on superposition model (SPM) analysis. Such identification of local sites with different magnetic properties would help us to understand not only the EPR spectra and magnetic susceptibility of other lanthanide ions doped in crystals with the same structure as YF{sub 3} but also the energy transfer scheme between two lanthanide ions occupying such two sites. All results are discussed carefully.

  18. Echo detected EPR as a tool for detecting radiation-induced defect signals in pottery

    International Nuclear Information System (INIS)

    Zoleo, Alfonso; Bortolussi, Claudia; Brustolon, Marina

    2011-01-01

    Archaeological fragments of pottery have been investigated by using CW-EPR and Echo Detected EPR (EDEPR). EDEPR allows to remove the CW-EPR dominant Fe(III) background spectrum, hiding much weaker signals potentially useful for dating purpose. EDEPR spectra attributed to a methyl radical and to feldspar defects have been recorded at room and low temperature for an Iron Age cooking ware (700 B.C.). A study on the dependence of EDEPR intensity over absorbed dose on a series of γ-irradiated brick samples (estimated age of 562 ± 140 B.C.) has confirmed the potential efficacy of the proposed method for spotting defect signals out of the strong iron background. - Highlights: → Fe(III) CW-EPR signals cover CW-EPR-detectable defects in ceramics. → Echo detected EPR gets rid of Fe(III) signals, disclosing defect signals. → Echo detected EPR detects defect signals even at relatively low doses.

  19. EPR spectral investigation of radiation-induced radicals of gallic acid

    International Nuclear Information System (INIS)

    Tuner, Hasan

    2017-01-01

    In the present work, spectroscopic features of the radiation-induced radicals of gallic acid compounds were investigated using electron paramagnetic resonance (EPR) spectroscopy. While un-irradiated samples presented no EPR signal, irradiated samples exhibited an EPR spectrum consisting of an intense resonance line at the center and weak lines on both sides. Detailed microwave saturation investigations were carried out to determine the origin of the experimental EPR lines. It is concluded that the two side lines of the triplet satellite originate from forbidden ''spin-flip'' transitions. The spectroscopic and structural features of the radiation-induced radicals were determined using EPR spectrum fittings. The experimental EPR spectra of the two gallic acid compounds were consistent with the calculated EPR spectroscopic features of the proposed radicals. It is concluded that the most probable radicals are the cyclohexadienyl-type, O(OH) 2 C 6 H 2 COOH radicals for both compounds. (orig.)

  20. EPR spectral investigation of radiation-induced radicals of gallic acid.

    Science.gov (United States)

    Tuner, Hasan

    2017-11-01

    In the present work, spectroscopic features of the radiation-induced radicals of gallic acid compounds were investigated using electron paramagnetic resonance (EPR) spectroscopy. While un-irradiated samples presented no EPR signal, irradiated samples exhibited an EPR spectrum consisting of an intense resonance line at the center and weak lines on both sides. Detailed microwave saturation investigations were carried out to determine the origin of the experimental EPR lines. It is concluded that the two side lines of the triplet satellite originate from forbidden "spin-flip" transitions. The spectroscopic and structural features of the radiation-induced radicals were determined using EPR spectrum fittings. The experimental EPR spectra of the two gallic acid compounds were consistent with the calculated EPR spectroscopic features of the proposed radicals. It is concluded that the most probable radicals are the cyclohexadienyl-type, [Formula: see text] radicals for both compounds.

  1. EPR researches of tree cuts for estimating radio - ecological situation

    International Nuclear Information System (INIS)

    Bitenbayev, M.I.; Polyakov, A.I.

    2007-01-01

    Full text: The basic aim of present work is to study a possibility of nature object application, in this case the annual rings of trees, for reveal of the effects of post - radiation action for them by EPR method. The cuts of poplars at the age 70 years and older grown in various regions of Kazakhstan with increased level of radiation background were selected as the research objects. EPR spectra were registered for every annual ring separately at the room temperatures. On the basis of EPR experimental results it was ascertained that the EPR spectra of annual rings may be symbolically divided for two groups every of which is possessed of its own definite kind of the spectrum. The first group are the spectra of the annual rings relating to 1981 - 1999 years (in 1999 the trees were cut), and the second group are these of the rings relating 1934 - 1980 years. At that it has been showed that an additional exposure to γ-ray of Co 60 transforms the first group spectrum to the form typical for the second group, i.e. the radiation effect becomes apparent in these experiments. The analyses of EPR spectra parameters has been performed and a correlation between the dependences of intensity of certain components in the spectrum on gamma - irradiation dose and the age of the annul rings has been showed. One can suppose that the intensity changing of these spectrum components in the second group, concerned with free radical accumulation, was the results of long-term action to the object by ionizing radiations. The studied effects can be used for average estimation of absorbed doses of ionizing radiation by environment objects, in particular, by residents of regions surveyed

  2. Accelerated dynamic EPR imaging using fast acquisition and compressive recovery.

    Science.gov (United States)

    Ahmad, Rizwan; Samouilov, Alexandre; Zweier, Jay L

    2016-12-01

    Electron paramagnetic resonance (EPR) allows quantitative imaging of tissue redox status, which provides important information about ischemic syndromes, cancer and other pathologies. For continuous wave EPR imaging, however, poor signal-to-noise ratio and low acquisition efficiency limit its ability to image dynamic processes in vivo including tissue redox, where conditions can change rapidly. Here, we present a data acquisition and processing framework that couples fast acquisition with compressive sensing-inspired image recovery to enable EPR-based redox imaging with high spatial and temporal resolutions. The fast acquisition (FA) allows collecting more, albeit noisier, projections in a given scan time. The composite regularization based processing method, called spatio-temporal adaptive recovery (STAR), not only exploits sparsity in multiple representations of the spatio-temporal image but also adaptively adjusts the regularization strength for each representation based on its inherent level of the sparsity. As a result, STAR adjusts to the disparity in the level of sparsity across multiple representations, without introducing any tuning parameter. Our simulation and phantom imaging studies indicate that a combination of fast acquisition and STAR (FASTAR) enables high-fidelity recovery of volumetric image series, with each volumetric image employing less than 10 s of scan. In addition to image fidelity, the time constants derived from FASTAR also match closely to the ground truth even when a small number of projections are used for recovery. This development will enhance the capability of EPR to study fast dynamic processes that cannot be investigated using existing EPR imaging techniques. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Chemistry of artemisinin: an EPR study and nucleobases interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mustafa, Damra Elhaj [Department of Chemistry, Faculty of Education, University of Khartoum, Khartoum (Sudan)

    2000-10-01

    In the present, the radical transformations of artemisinin, a potent antimalarial drug have been examined using EPR and EPR spin trapping techniques. The effect of light on artemisinin has been investigated at 77 K as well as with the use of phenyl butyl nitrone (PBN) spin trapping agent. While no EPR signal was observed at 77 K, intense light irradiation of artemisinin/PBN gave EPR signal characteristic of radical transformation of the PBN. The reactions of artemisinin with iron (II), manganese (II), hemin and ferrocyanide ion have been investigated by spin trapping techniques. Artemisinin/iron (II) formed spin adducts with nitrosobenzene, nitroso-t-butane and PBN. The hypertine splittings of the spin adducts were a{sub N}=1.08 mT/a{sub N}=1.25 mT/a{sub N}=0.09 mT and a{sub N}=1.56 mT/a{sub N}=0.29 mT respectively. PBN trapping of artemether/iron (II) gave similar result to artemisinin/iron (II). These results are indicative of secondary carbon-centered radical formation. While artemisinin/hemin/PBN gave very weak EPR signal, ferrocyanide under the same condition gave no signal. Incubation of artemisinin with RNA at different reaction conditions, including irradiation with light, heat and mild acidic media, revealed no RNA damage when examined by agarose electrophoresis. However, artemisinin/iron (II) caused RNA damage in pH-dependant manner. In contrast, hemin did not show the same effect when it was used instead of iron (II). (Author)

  4. Chemistry of artemisinin: an EPR study and nucleobases interaction

    International Nuclear Information System (INIS)

    Mustafa, Damra Elhaj

    2000-10-01

    In the present, the radical transformations of artemisinin, a potent antimalarial drug have been examined using EPR and EPR spin trapping techniques. The effect of light on artemisinin has been investigated at 77 K as well as with the use of phenyl butyl nitrone (PBN) spin trapping agent. While no EPR signal was observed at 77 K, intense light irradiation of artemisinin/PBN gave EPR signal characteristic of radical transformation of the PBN. The reactions of artemisinin with iron (II), manganese (II), hemin and ferrocyanide ion have been investigated by spin trapping techniques. Artemisinin/iron (II) formed spin adducts with nitrosobenzene, nitroso-t-butane and PBN. The hypertine splittings of the spin adducts were a N =1.08 mT/a N =1.25 mT/a N =0.09 mT and a N =1.56 mT/a N =0.29 mT respectively. PBN trapping of artemether/iron (II) gave similar result to artemisinin/iron (II). These results are indicative of secondary carbon-centered radical formation. While artemisinin/hemin/PBN gave very weak EPR signal, ferrocyanide under the same condition gave no signal. Incubation of artemisinin with RNA at different reaction conditions, including irradiation with light, heat and mild acidic media, revealed no RNA damage when examined by agarose electrophoresis. However, artemisinin/iron (II) caused RNA damage in pH-dependant manner. In contrast, hemin did not show the same effect when it was used instead of iron (II). (Author)

  5. EPR (European Pressurized water Reactor) The advanced nuclear reactor

    International Nuclear Information System (INIS)

    2004-01-01

    Nuclear energy, which provides a steady supply of electricity at low cost, has its rightful place in the energy mix of the 21. century, which puts the emphasis on sustainable development. The EPR is the only 3. generation reactor under construction today. It is an evolutionary reactor that represents a new generation of pressurized water reactors with no break in the technology used for the most recent models. The EPR was developed by Framatome and Siemens, whose nuclear activities were combined in January 2001 to form Framatome ANP, a subsidiary of AREVA and Siemens. EDF and the major German electricity companies played an active part in the project. The safety authorities of the two countries joined forces to bring their respective safety standards into line and draw up joint design rules for the new reactor. The project had three objectives: meet the requirements of European utilities, comply with the safety standards laid down by the French safety authority for future pressurized water reactors, in concert with its German counterpart, and make nuclear energy even more competitive than energy generated using fossil fuels. The EPR can guarantee a safe, inexpensive electricity supply, without adding to the greenhouse effect. It meets the requirements of the safety authorities and lives up to the expectations of electricity utilities. This document presents the main characteristics of the EPR, and in particular the additional measures to prevent the occurrence of events likely to damage the core, the leak-tight containment, the measures to reduce the exposure of operating and maintenance personnel, the solutions for an even greater protection of the environment. The foreseen development of the EPR in France and abroad (Finland, China, the United States) is summarized

  6. Three-Dimensional Reconstruction of Cloud-to-Ground Lightning Using High-Speed Video and VHF Broadband Interferometer

    Science.gov (United States)

    Li, Yun; Qiu, Shi; Shi, Lihua; Huang, Zhengyu; Wang, Tao; Duan, Yantao

    2017-12-01

    The time resolved three-dimensional (3-D) spatial reconstruction of lightning channels using high-speed video (HSV) images and VHF broadband interferometer (BITF) data is first presented in this paper. Because VHF and optical radiations in step formation process occur with time separation no more than 1 μs, the observation data of BITF and HSV at two different sites provide the possibility of reconstructing the time resolved 3-D channel of lightning. With the proposed procedures for 3-D reconstruction of leader channels, dart leaders as well as stepped leaders with complex multiple branches can be well reconstructed. The differences between 2-D speeds and 3-D speeds of leader channels are analyzed by comparing the development of leader channels in 2-D and 3-D space. Since return stroke (RS) usually follows the path of previous leader channels, the 3-D speeds of the return strokes are first estimated by combination with the 3-D structure of the preceding leaders and HSV image sequences. For the fourth RS, the ratios of the 3-D to 2-D RS speeds increase with height, and the largest ratio of the 3-D to 2-D return stroke speeds can reach 2.03, which is larger than the result of triggered lightning reported by Idone. Since BITF can detect lightning radiation in a 360° view, correlated BITF and HSV observations increase the 3-D detection probability than dual-station HSV observations, which is helpful to obtain more events and deeper understanding of the lightning process.

  7. Investigation of atmospheric high-energy phenomena onboard International Space Station: microsatellite ''Chibis-AI'' and VHF interferometer ''Kite''

    International Nuclear Information System (INIS)

    Dolgonosov, M.; Gotlib, V.; Karedin, V.; Kosov, A.; Nazarov, V.; Zelenyi, L.; Klimov, S.

    2017-01-01

    Space Research Institute of the RAS is gradually developing its own program of the space-born experiments to study high- energy process in the terrestrial atmosphere. Terrestrial Gamma-ray Flashes (TGFS) and Compact Intracloud Discharges (CIDs) are among principal goals of the scientific research of the program. To conduct research is supposed to produce new «instruments»: microsatellite «ChibiS-AI» and VHF interferometer «Kite» aboard International Space Station. Microsatellite ”Chibis-AI” will be constructed on the platform originally designed at the Special Engineering Department of Space Research Institute of the Russian Academy of Sciences in 2011. It's forerunner «Chibis-M» was successfully launched in 2012. Expected date of «Chibis-AI» launch is 2019. The principal idea underlying design of the scientific payload of the microsatellite ”Chibis-AI” is the joint observations of the TGF and CID emissions by different detectors installed onboard: Radio Frequency Analyzer (RFA) and Neutron and Gamma spectrometer (N GS). RFA contained two passbands in the range 15-26 and 26-48 MHZ with a digitization at 96 megasamples/s. NGS is based on LaBr3(Ce3+) crystal with the maximum achievable today spectral resolution and efficiency of gamma rays in the energy range 100 Kev - 10 MeV among scintillation crystals. The microsatellite orbit will be circular with inclination 51° with initial elevation above sea level around 550 km. VHF interferometer «Kite» to be installed in 2019-2020 aboard 188. To implement interferometric scheme 4 antennas will be installed on the 188 surface. The passband of the instrument will be ∼50-100 MHZ. Technical details of both experiments, its current stage and features as well results of the previous experiment «Chibis-M» will be discussed. (author)

  8. Investigation of inertia-gravity waves in the upper troposphere/lower stratosphere over Northern Germany observed with collocated VHF/UHF radars

    Directory of Open Access Journals (Sweden)

    A. Serafimovich

    2005-01-01

    Full Text Available A case study to investigate the properties of inertia-gravity waves in the upper troposphere/lower stratosphere has been carried out over Northern Germany during the occurrence of an upper tropospheric jet in connection with a poleward Rossby wave breaking event from 17-19 December 1999. The investigations are based on the evaluation of continuous radar measurements with the OSWIN VHF radar at Kühlungsborn (54.1 N, 11.8 E and the 482 MHz UHF wind profiler at Lindenberg (52.2 N, 14.1 E. Both radars are separated by about 265 km. Based on wavelet transformations of both data sets, the dominant vertical wavelengths of about 2-4 km for fixed times as well as the dominant observed periods of about 11 h and weaker oscillations with periods of  6 h for the altitude range between 5 and 8 km are comparable. Gravity wave parameters have been estimated at both locations separately and by a complex cross-spectral analysis of the data of both radars. The results show the appearance of dominating inertia-gravity waves with characteristic horizontal wavelengths of  300 km moving in the opposite direction than the mean background wind and a secondary less pronounced wave with a horizontal wavelength in the order of about 200 km moving with the wind. Temporal and spatial differences of the observed waves are discussed.

  9. Investigations in quantum games using EPR-type set-ups

    Science.gov (United States)

    Iqbal, Azhar

    2006-04-01

    Research in quantum games has flourished during recent years. However, it seems that opinion remains divided about their true quantum character and content. For example, one argument says that quantum games are nothing but 'disguised' classical games and that to quantize a game is equivalent to replacing the original game by a different classical game. The present thesis contributes towards the ongoing debate about quantum nature of quantum games by developing two approaches addressing the related issues. Both approaches take Einstein-Podolsky-Rosen (EPR)-type experiments as the underlying physical set-ups to play two-player quantum games. In the first approach, the players' strategies are unit vectors in their respective planes, with the knowledge of coordinate axes being shared between them. Players perform measurements in an EPR-type setting and their payoffs are defined as functions of the correlations, i.e. without reference to classical or quantum mechanics. Classical bimatrix games are reproduced if the input states are classical and perfectly anti-correlated, as for a classical correlation game. However, for a quantum correlation game, with an entangled singlet state as input, qualitatively different solutions are obtained. The second approach uses the result that when the predictions of a Local Hidden Variable (LHV) model are made to violate the Bell inequalities the result is that some probability measures assume negative values. With the requirement that classical games result when the predictions of a LHV model do not violate the Bell inequalities, our analysis looks at the impact which the emergence of negative probabilities has on the solutions of two-player games which are physically implemented using the EPR-type experiments.

  10. SPIDYAN, a MATLAB library for simulating pulse EPR experiments with arbitrary waveform excitation.

    Science.gov (United States)

    Pribitzer, Stephan; Doll, Andrin; Jeschke, Gunnar

    2016-02-01

    Frequency-swept chirp pulses, created with arbitrary waveform generators (AWGs), can achieve inversion over a range of several hundreds of MHz. Such passage pulses provide defined flip angles and increase sensitivity. The fact that spectra are not excited at once, but single transitions are passed one after another, can cause new effects in established pulse EPR sequences. We developed a MATLAB library for simulation of pulse EPR, which is especially suited for modeling spin dynamics in ultra-wideband (UWB) EPR experiments, but can also be used for other experiments and NMR. At present the command line controlled SPin DYnamics ANalysis (SPIDYAN) package supports one-spin and two-spin systems with arbitrary spin quantum numbers. By providing the program with appropriate spin operators and Hamiltonian matrices any spin system is accessible, with limits set only by available memory and computation time. Any pulse sequence using rectangular and linearly or variable-rate frequency-swept chirp pulses, including phase cycling can be quickly created. To keep track of spin evolution the user can choose from a vast variety of detection operators, including transition selective operators. If relaxation effects can be neglected, the program solves the Liouville-von Neumann equation and propagates spin density matrices. In the other cases SPIDYAN uses the quantum mechanical master equation and Liouvillians for propagation. In order to consider the resonator response function, which on the scale of UWB excitation limits bandwidth, the program includes a simple RLC circuit model. Another subroutine can compute waveforms that, for a given resonator, maintain a constant critical adiabaticity factor over the excitation band. Computational efficiency is enhanced by precomputing propagator lookup tables for the whole set of AWG output levels. The features of the software library are discussed and demonstrated with spin-echo and population transfer simulations. Copyright © 2016

  11. The EPR - a safe and competitive solution for future energy needs

    International Nuclear Information System (INIS)

    Fischer, U.; Bouteille, F.; Leverenz, R.

    1999-01-01

    NPI, Siemens and Framatome, in co-operation with EDF and the major German Utilities, started the development of the European Pressurized Water Reactor (EPR) as an evolutionary approach. After a careful evaluation of the potential of passive safety features, this way was concluded to be superior compared to a 'revolutionary' approach. The vast majority of advanced reactor designs being developed today is of the evolutionary type. The advantages to base an advanced design on the feedback of operation experience of the more than 100 nuclear power plants designed and constructed by Siemens and Framatome are outstanding. This view is shared by the German and French safety authorities which defined their preference for an evolutionary design early at the beginning of their co-operation for the definition of a common safety approach for future nuclear power plants to be built in Germany and France. In their first common set of recommendations, they gave a clear guideline regarding their point of view for requirements posed to the next generation of nuclear power plants: (1) Preference for an evolutionary design in order to derive a maximum benefit from experience; (2) Significant safety improvements by reduction of core meltdown probability and improvement of the confinement function of the containment under accident conditions; (3) Improvement of operating conditions regarding radiation protection, maintenance and human errors. Besides the French-German co-operation of vendors, utilities and authorities, the European utilities co-operate on a much broader basis for the establishment of the European Utilities' Requirements (EUR). During the development of the basic design, the EPR was continuously assessed against these EUR and it was concluded that the EPR complies with these requirements. At the end of the basic design phase at the end of 1997, all information necessary to file a preliminary safety analysis report and a reliable bill of quantities was elaborated. With

  12. EFFECT OF MICROWAVE POWER ON SHAPE OF EPR SPECTRA--APPLICATION TO EXAMINATION OF COMPLEX FREE RADICAL SYSTEM IN THERMALLY STERILIZED ACIDUM BORICUM.

    Science.gov (United States)

    Ramos, Paweł; Pieprzyca, Małgorzata; Pilawa, Barbara

    2016-01-01

    Complex free radical system in thermally sterilized acidum boricum (AB) was studied. Acidum boricum was sterilized at temperatures and times given by pharmaceutical norms: 160 degrees C and 120 min, 170 degrees C and 60 min and 180 degrees C and 30 min. The advanced spectroscopic tests were performed. The EPR spectra of free radicals were measured as the first derivatives with microwaves of 9.3 GHz frequency and magnetic modulation of 100 kHz. The Polish X-band electron paramagnetic resonance spectrometer of Radiopan (Poznań) was used. EPR lines were not observed for the nonheated AB. The broad EPR asymmetric lines were obtained for all the heated AB samples. The influence of microwave power in the range of 2.2-70 mW on the shape of EPR spectra of the heated drug samples was tested. The following asymmetry parameters: A1/A2, A1-A2, B1/B2, and B1-B2, were analyzed. The changes of these parameters with microwave power were observed. The strong dependence of shape and its parameters on microwave power proved the complex character of free radical system in thermally sterilized AB. Changes of microwave power during the detection of EPR spectra indicated complex character of free radicals in AB sterilized in hot air under all the tested conditions. Thermolysis, interactions between free radicals and interactions of free radicals with oxygen may be responsible for the complex free radicals system in thermally treated AB. Usefulness of continuous microwave saturation of EPR lines and shape analysis to examine free radicals in thermally sterilized drugs was confirmed.

  13. Increase of weakly acidic gas esophagopharyngeal reflux (EPR) and swallowing-induced acidic/weakly acidic EPR in patients with chronic cough responding to proton pump inhibitors.

    Science.gov (United States)

    Kawamura, O; Shimoyama, Y; Hosaka, H; Kuribayashi, S; Maeda, M; Nagoshi, A; Zai, H; Kusano, M

    2011-05-01

    Gastro-esophageal reflux disease (GERD)-related chronic cough (CC) may have multifactorial causes. To clarify the characteristics of esophagopharyngeal reflux (EPR) events in CC patients whose cough was apparently influenced by gastro-esophageal reflux (GER), we studied patients with CC clearly responding to full-dose proton pump inhibitor (PPI) therapy (CC patients). Ten CC patients, 10 GERD patients, and 10 healthy controls underwent 24-h ambulatory pharyngo-esophageal impedance and pH monitoring. Weakly acidic reflux was defined as a decrease of pH by >1 unit with a nadir pH >4. In six CC patients, monitoring was repeated after 8 weeks of PPI therapy. The number of each EPR event and the symptom association probability (SAP) were calculated. Symptoms were evaluated by a validated GERD symptom questionnaire. Weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR only occurred in CC patients, and the numbers of such events was significantly higher in the CC group than in the other two groups (P pump inhibitor therapy abolished swallowing-induced acidic/weakly acidic EPR, reduced weakly acidic gas EPR, and improved symptoms (all P gas EPR and swallowing-induced acidic/weakly acidic EPR. A direct effect of acidic mist or liquid refluxing into the pharynx may contribute to chronic cough, while cough may also arise indirectly from reflux via a vago-vagal reflex in some patients. © 2011 Blackwell Publishing Ltd.

  14. Study of paramagnetic defect centers in as-grown and annealed TiO2 anatase and rutile nanoparticles by a variable-temperature X-band and high-frequency (236 GHz) EPR.

    Science.gov (United States)

    Misra, S K; Andronenko, S I; Tipikin, D; Freed, J H; Somani, V; Prakash, Om

    2016-03-01

    Detailed EPR investigations on as-grown and annealed TiO 2 nanoparticles in the anatase and rutile phases were carried out at X-band (9.6 GHz) at 77, 120-300 K and at 236 GHz at 292 K. The analysis of EPR data for as-grown and annealed anatase and rutile samples revealed the presence of several paramagnetic centers: Ti 3+ , O - , adsorbed oxygen (O 2 - ) and oxygen vacancies. On the other hand, in as-grown rutile samples, there were observed EPR lines due to adsorbed oxygen (O 2 - ) and the Fe 3+ ions in both Ti 4+ substitutional positions, with and without coupling to an oxygen vacancy in the near neighborhood. Anatase nanoparticles were completely converted to rutile phase when annealed at 1000° C, exhibiting EPR spectra similar to those exhibited by the as-grown rutile nanoparticles. The high-frequency (236 GHz) EPR data on anatase and rutile samples, recorded in the region about g = 2.0 exhibit resolved EPR lines, due to O - and O 2 - ions enabling determination of their g-values with higher precision, as well as observation of hyperfine sextets due to Mn 2+ and Mn 4+ ions in anatase.

  15. An X-band Co2+ EPR study of Zn1-xCoxO (x=0.005-0.1) nanoparticles prepared by chemical hydrolysis methods using diethylene glycol and denaturated alcohol at 5 K

    Science.gov (United States)

    Misra, Sushil K.; Andronenko, S. I.; Srinivasa Rao, S.; Chess, Jordan; Punnoose, A.

    2015-11-01

    EPR investigations on two types of dilute magnetic semiconductor (DMS) ZnO nanoparticles doped with 0.5-10% Co2+ ions, prepared by two chemical hydrolysis methods, using: (i) diethylene glycol ((CH2CH2OH)2O) (NC-rod-like samples), and (ii) denatured ethanol (CH3CH2OH) solutions (QC-spherical samples), were carried out at X-band (9.5 GHz) at 5 K. The analysis of EPR data for NC samples revealed the presence of several types of EPR lines: (i) two types, intense and weak, of high-spin Co2+ ions in the samples with Co concentration >0.5%; (ii) surface oxygen vacancies, and (iii) a ferromagnetic resonance (FMR) line. QC samples exhibit an intense FMR line and an EPR line due to high-spin Co2+ ions. FMR line is more intense, than the corresponding line exhibited by NC samples. These EPR spectra varied for sample with different doping concentrations. The magnetic states of these samples as revealed by EPR spectra, as well as the origin of ferromagnetism DMS samples are discussed.

  16. Medical reference dosimetry using EPR measurements of alanine

    DEFF Research Database (Denmark)

    Helt-Hansen, Jakob; Rosendal, F.; Kofoed, I.M.

    2009-01-01

    Background. Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low...... methods the proposed algorithm can be applied without normalisation of phase shifts caused by changes in the g-value of the cavity. The study shows that alanine dosimetry is a suitable candidate for medical reference dosimetry especially for quality control applications.......Background. Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low...

  17. Spatially distributed multipartite entanglement enables EPR steering of atomic clouds

    Science.gov (United States)

    Kunkel, Philipp; Prüfer, Maximilian; Strobel, Helmut; Linnemann, Daniel; Frölian, Anika; Gasenzer, Thomas; Gärttner, Martin; Oberthaler, Markus K.

    2018-04-01

    A key resource for distributed quantum-enhanced protocols is entanglement between spatially separated modes. However, the robust generation and detection of entanglement between spatially separated regions of an ultracold atomic system remain a challenge. We used spin mixing in a tightly confined Bose-Einstein condensate to generate an entangled state of indistinguishable particles in a single spatial mode. We show experimentally that this entanglement can be spatially distributed by self-similar expansion of the atomic cloud. We used spatially resolved spin read-out to reveal a particularly strong form of quantum correlations known as Einstein-Podolsky-Rosen (EPR) steering between distinct parts of the expanded cloud. Based on the strength of EPR steering, we constructed a witness, which confirmed genuine 5-partite entanglement.

  18. EPR assessment of the free radicals in irradiated foodstuffs

    International Nuclear Information System (INIS)

    Tencheva, S.; Katsareva, Ts.; Malinovski, A.; Kabasanov, K.

    1985-01-01

    In the hygienic assessment of radiation treated foodstuffs the study of free radicals formed during radiation exposure, their concentration and disintegration kinetics are of particular interest. In the work presented the concentration of the free radicals in irradiated prunes, nuts and corn is determined using EPR spectroscopy. The following doses are applied: 2, 10 and 20 kGy for prunes, 1, 10 and 20 kGy for nuts, and 0.75, 10 and 20 kGy for corn. EPR measurements are done immediately after the irradiation: 24 hours, and 3, 6, 9 and 15 days after the exposure. In the small radiation doses the formation of single radicals is observed. In doses of 10 kGy the spectra get complicated with the occurence of radicals R 1 , R 2 , R 3 and R 4 . The assessment of radicals proves to be a prospective method for the identification and determination of the preservation terms of foodstuffs

  19. Geographic Variations in the EPR Spectrum of Tooth Enamel

    International Nuclear Information System (INIS)

    Romanyukha, A.A.; Hayes, R.B.; Haskell, E.H.; Kenner, G.H.

    1999-01-01

    The presence of stable radiation-induced radicals in the mineral component of tooth enamel allows use of this material as a biological dosemeter. Estimation of the dose absorbed in tooth enamel can be done by EPR. Generally, for the purpose of dose reconstruction, the EPR spectrum of tooth enamel is interpreted in terms of two main components. The first is a broad background signal often called the native signal centered at a g value of 2.0045. The origin of this signal is not precisely known. The second main component in the tooth enamel spectrum is purely radiation induced and can be used for retrospective dosimetry. Internal structure of the native signal and variations of its amplitude and linewidth were investigated for the samples prepared from modern teeth obtained from different geographic locations (USA and Russia). Possible reasons for the variations observed are discussed as are the potential effects of the variations on the reliability of dose estimation. (author)

  20. The Chernobyl accident: EPR dosimetry on dental enamel of children

    International Nuclear Information System (INIS)

    Gualtieri, G.; Colacicchi, S.; Sgattoni, R.; Giannoni, M.

    2001-01-01

    The radiation dose on tooth enamel of children living close to Chernobyl has been evaluated by EPR. The sample preparation was reduced to a minimum of mechanical steps to remove a piece of enamel. A standard X-ray tube at low energy was used for additive irradiation. The filtration effect of facial soft tissue was taken into account. The radiation dose for a group of teeth slightly exceeds the annual dose, whereas for another group the dose very much exceeds the annual dose. Since the higher dose is found in teeth whose enamel have much lower EPR sensitivity to the radiation, it can be suggested that for these teeth the native signal could alter the evaluation of the smaller radiation signal

  1. EPR spectroscopy can help with paint pigment provenance

    International Nuclear Information System (INIS)

    Troup, G.J.; Hutton, D.R.

    2000-01-01

    Full text: The microwave magnetic spectroscopic technique EPR can be used to determine the presence of paramagnetic impurities in paint pigments, and the purity of composition regarding the main colourant. Hence EPR can help determine provenance of pigments, just as it can for gemstones. Specimens of Lapis Lazuli (synthetic, Afghanistan, Chile, Greenland) showed quite recognisably different spectra, at room temperature, in a Varian E-12 X-band spectrometer (9.1 GHz frequency). Similarly, specimens of yellow ochre, two imported into Australia, one North Australian, another 95% pure Goethite, showed recognisably different spectra. The North Australian one uniquely gave a known radiation damage signal from quartz, perhaps to be expected, given the abundance of radioactive ores in the region. Further samples have been obtained and the results from these will be reported

  2. On the computer simulation of the EPR-Bohm experiment

    International Nuclear Information System (INIS)

    McGoveran, D.O.; Noyes, H.P.; Manthey, M.J.

    1988-12-01

    We argue that supraluminal correlation without supraluminal signaling is a necessary consequence of any finite and discrete model for physics. Every day, the commercial and military practice of using encrypted communication based on correlated, pseudo-random signals illustrates this possibility. All that is needed are two levels of computational complexity which preclude using a smaller system to detect departures from ''randomness'' in the larger system. Hence the experimental realizations of the EPR-Bohm experiment leave open the question of whether the world of experience is ''random'' or pseudo-random. The latter possibility could be demonstrated experimentally if a complexity parameter related to the arm length and switching time in an Aspect-type realization of the EPR-Bohm experiment is sufficiently small compared to the number of reliable total counts which can be obtained in practice. 6 refs

  3. A transferability study of the EPR-tooth-dosimetry technique

    International Nuclear Information System (INIS)

    Sholom, S.; Chumak, V.; Desrosiers, M.; Bouville, A.

    2006-01-01

    The transferability of a measurement protocol from one laboratory to another is an important feature of any mature, standardised protocol. The electron paramagnetic resonance (EPR)-tooth dosimetry technique that was developed in Scientific Center for Radiation Medicine, AMS (Ukraine) (SCRM) for routine dosimetry of Chernobyl liquidators has demonstrated consistent results in several inter-laboratory measurement comparisons. Transferability to the EPR dosimetry laboratory at the National Inst. of Standards and Technology (NIST) was examined. Several approaches were used to test the technique, including dose reconstruction of SCRM-NIST inter-comparison samples. The study has demonstrated full transferability of the technique and the possibility to reproduce results in a different laboratory environment. (authors)

  4. EPR of divalent manganese in non-Kramers hosts

    Energy Technology Data Exchange (ETDEWEB)

    Lech, J.; Slezak, A. [Institute of Physics, Technical University of Czestochowa, Czestochowa (Poland)

    1997-12-31

    Various interactions which lead to the observation of sharp EPR spectra of the high half-integer spin impurity Mn{sup 2+} (S=5/2) in paramagnetic hosts with integer spins S=1 and S=2 have been studied. Studies have been carried out on the basis of data extracted from experimental EPR spectra of Mn{sup 2+} in single crystal of divalent nickel Ni{sup 2+} (S=1) and Fe{sup 2+} (S=1) perchlorate hexahydrates. It has been shown that dipolar host-host and host-guest couplings broaden resonance lines of Mn{sup 2+}. Narrowing of the lines in the both crystals can be mainly attributed to the host-guest exchange interactions and quenching of the host spins. 19 refs, 3 figs, 1 tab.

  5. The EPR-a comprehensive design concept against external events

    International Nuclear Information System (INIS)

    Stoll, U.; Waas, U.

    2006-01-01

    The main objective of design provisions against external hazards is to ensure that the safety functions required to bring the plant to safe shutdown are not inadmissibly affected by any external hazards that might be postulated for the intended site of the plant. In the design of the European Pressurized Water Reactor (EPR) particular attention was paid to external hazards such as earthquake, airplane crash, and explosion pressure wave. The standard EPR covers a large range of possible site conditions, the design earthquake enveloping safe shutdown earthquakes (SSE) to be expected for potential sites. The loads for the design basis airplane crash and - if required - for the design extension airplane crash as well as for external Explosion Pressure Wave are defined depending on site specific requirements. Protection against other external load cases such as extreme winds and external flooding is also included in the standard design

  6. EPR dosimetry in a mixed neutron and gamma radiation field.

    Science.gov (United States)

    Trompier, F; Fattibene, P; Tikunov, D; Bartolotta, A; Carosi, A; Doca, M C

    2004-01-01

    Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident absorbed dose, analyzed results show the EPR potentiality and complementarity with regular criticality techniques.

  7. Investigations of the EPR reference concept (KATS experiments)

    International Nuclear Information System (INIS)

    Fieg, G.; Werle, H.; Huber, F.

    1995-01-01

    The reference concept of an EPR core catcher envisages the spreading of the melt on a protective layer (150 m 2 area) and water cooling from above. Two variants are considered: Spreading on a dry area and on an area covered by water of condensation (1 cm depth). For the reference concept the KATS experiments are performed with thermite melts. After initial problems had rendered it difficult to interprete the first test, repeated tests have been successful. (orig.)

  8. Krótka (pre)historia argumentu EPR

    OpenAIRE

    Tadeusz Pabjan

    2010-01-01

    The 1935 thought experiment of Einstein, Podolsky and Rosen is one of the most important episodes in the history of the dispute about the correct interpretation of quantum mechanics. The present paper deals with the origin of the EPR paper and discusses some other thought experiments that preceded the formulation of the Einstein-Podolsky-Rosen argument. Special attention is paid to the evolution of a simply photon-box experiment, which was devised by Einstein in 1930 and then modified by him ...

  9. Copenhagen vs Everett, teleportation, and ER=EPR

    Energy Technology Data Exchange (ETDEWEB)

    Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA (United States)

    2016-06-15

    Quantum gravity may have as much to tell us about the foundations and interpretation of quantum mechanics as it does about gravity. The Copenhagen interpretation of quantum mechanics and Everett's Relative State Formulation are complementary descriptions which in a sense are dual to one another. My purpose here is to discuss this duality in the light of the of ER=EPR conjecture. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. The implementation of advanced EPR in the US

    International Nuclear Information System (INIS)

    Hagan, C.; Mico, F.

    2007-01-01

    As electricity demand, clean air concerns and energy prices increase in the U. S., interest in the new nuclear reactors is also on the rise. These factors, along with decades of outstanding performance of the nations existing fleet, have contributed to a favourable market of new nuclear power in the U.S.This article presents some reflexions about the new situation of the market and the response that AREVA offers to he North American Electric utilities: The EPR. (Author)

  11. EPR dosimetric properties of nano-barium sulfate

    International Nuclear Information System (INIS)

    Aboelezz, E.; Hassan, G.M.; Sharaf, M.A.; El-Khodary, A.

    2015-01-01

    Nano/micro BaSO 4 were prepared through the co-precipitation method to measure ionizing radiation doses using electron paramagnetic resonance (EPR). The nano-BaSO 4 sample was characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The dose response and fading properties of nano- and micro-phase BaSO 4 were compared in EPR spectra. The prepared nano- and micro-BaSO 4 samples have the same hole and electron centers, which may be attributed to SO 4 − and SO 3 − , respectively. The dosimetric signals for prepared nano- and micro-BaSO 4 have spectroscopic splitting factor (g) with values 2.0025±0.0006 and 2.0027±0.0006, respectively. The nanocrystalline sample has a linear γ-ray dose response over the range 0.4 Gy–1 kGy. The performance parameters which including detection limit and critical level calculated from weighted and unweighted least-squares fitting. The sensitivity of nano-BaSO 4 to γ-ray is one and a half times more than alanine. The lifetime and activation energy for nano-BaSO 4 were estimated by conducting a thermal stability study, and were 5.7±1.1×10 4 years and 0.73±0.14 eV, respectively. The combined and expanded uncertainties accompanying measurements were ±3.89% and ±7.78%, respectively. - Highlights: • Preparation of nano-BaSO 4 using the co-precipitation method. • Study of the dosimetric properties of nano-barium sulfate using the EPR technique. • Comparison between a new EPR dosimeter using nano-materials and standard alanine. • Calculation of the uncertainty budget for nano-BaSO 4

  12. EPR spectroscopy in the asphaltenes photodegradation study in petroleum

    International Nuclear Information System (INIS)

    Mauro, Eduardo di; Nakaema, Marcelo Kiyoshi Kian; Melo, Fernando Alves de; Turini, Marilene; Guedes, Carmen Luisa Barbosa; Nascimento, Otaciro Rangel

    2003-01-01

    Full text: The knowledge of the photochemistry transformation that occurs in the petroleum, when it is exposed to the environment has already been proved. In tropical climates, where the solar intensity is high and biological processes are hindered by the lack of nutrients, photochemical processes can be the one that most contribute for the degradation of oil. Moreover, photochemical processes can be important for subsequent biological consumption of oil (Nicodem et al., 1997). We have used EPR with the purpose of getting information of the photodegradation of the asphaltenes concerning the molecular structure. The EPR spectra of petroleum presented a single sign for organic free radicals. The present work basically consists of showing a new assignment of the EPR spectra to organic free radical. The sign observed in the EPR spectra in the Q-band for Arabian and Colombian oils was simulated mathematically. In contrast to the hypothesis postulated until now, that the sign corresponding to the free radical is interpreted as resulting from the superposition of the signs of different species of radicals in petroleum asphaltenes, the hypothesis that the asymmetrical line is the result of the components of the g tensor for a single radical species was proposed. The performed simulation was perfectly adjusted to the sign of the radical, confirming that this sign is the representation of a single species of free radical. Although the sign of the radical is due to a single species in each oil, the species responsible for the sign in Arabian petroleum is different from that responsible for the sign in Colombian petroleum. Nicodem, D.E., Fernandes, M.C.Z., Guedes, C.L.B., Correia, R.J., 1997. Biogeochemistry 39, 121-138. (author)

  13. Karl R. Popper, 1992: About the EPR controversy

    Science.gov (United States)

    Combourieu, Marie-Christine

    1992-10-01

    Sir K. R. Popper's experimental schemes challenge the Copenhagen interpretation of quantum theory, principally Heisenberg's indeterminacy relations and the EPR paradox. “The so-called Einstein-Podolsky-Rosen paradox is not a paradox. It is a theoretical statement in expectation of an interpretation,” says K. R. Popper in this interview. “My experiment ought to be a classical experiment. It is very simple and free from any additional assumption. It should really be done.”

  14. EPR studies of cooperative binding of Cu (II) to hemoglobin

    International Nuclear Information System (INIS)

    Louro, S.R.W.; Tabak, M.

    1983-07-01

    The investigation of the relative affinities of the two pairs of hemoglobin copper sites by monitoring the EPR spectra of the complexes formed by the reaction of copper with deoxyhemoglobin is reported. A model in which two sites are assumed to accept copper ions in a noncooperative way is not able to predict the experimental results. Thus it is conclude that the binding of these ions to hemoglobin is a cooperative phenomenon. (Author) [pt

  15. Toward 2D and 3D imaging of magnetic nanoparticles using EPR measurements.

    Science.gov (United States)

    Coene, A; Crevecoeur, G; Leliaert, J; Dupré, L

    2015-09-01

    Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance (EPR). Currently only 1D MNP distributions can be reconstructed. In this paper, the authors propose extending 1D EPR toward 2D and 3D using computer simulations to allow accurate imaging of MNP distributions. To find the MNP distribution belonging to EPR measurements, an inverse problem needs to be solved. The solution of this inverse problem highly depends on the stability of the inverse problem. The authors adapt 1D EPR imaging to realize the imaging of multidimensional MNP distributions. Furthermore, the authors introduce partial volume excitation in which only parts of the volume are imaged to increase stability of the inverse solution and to speed up the measurements. The authors simulate EPR measurements of different 2D and 3D MNP distributions and solve the inverse problem. The stability is evaluated by calculating the condition measure and by comparing the actual MNP distribution to the reconstructed MNP distribution. Based on these simulations, the authors define requirements for the EPR system to cope with the added dimensions. Moreover, the authors investigate how EPR measurements should be conducted to improve the stability of the associated inverse problem and to increase reconstruction quality. The approach used in 1D EPR can only be employed for the reconstruction of small volumes in 2D and 3D EPRs due to numerical instability of the inverse solution. The authors performed EPR measurements of increasing cylindrical volumes and evaluated the condition measure. This showed that a reduction of the inherent symmetry in the EPR methodology is necessary. By reducing the symmetry of the EPR setup, quantitative images of larger volumes can be

  16. Toward 2D and 3D imaging of magnetic nanoparticles using EPR measurements

    International Nuclear Information System (INIS)

    Coene, A.; Crevecoeur, G.; Dupré, L.; Leliaert, J.

    2015-01-01

    Purpose: Magnetic nanoparticles (MNPs) are an important asset in many biomedical applications. An effective working of these applications requires an accurate knowledge of the spatial MNP distribution. A promising, noninvasive, and sensitive technique to visualize MNP distributions in vivo is electron paramagnetic resonance (EPR). Currently only 1D MNP distributions can be reconstructed. In this paper, the authors propose extending 1D EPR toward 2D and 3D using computer simulations to allow accurate imaging of MNP distributions. Methods: To find the MNP distribution belonging to EPR measurements, an inverse problem needs to be solved. The solution of this inverse problem highly depends on the stability of the inverse problem. The authors adapt 1D EPR imaging to realize the imaging of multidimensional MNP distributions. Furthermore, the authors introduce partial volume excitation in which only parts of the volume are imaged to increase stability of the inverse solution and to speed up the measurements. The authors simulate EPR measurements of different 2D and 3D MNP distributions and solve the inverse problem. The stability is evaluated by calculating the condition measure and by comparing the actual MNP distribution to the reconstructed MNP distribution. Based on these simulations, the authors define requirements for the EPR system to cope with the added dimensions. Moreover, the authors investigate how EPR measurements should be conducted to improve the stability of the associated inverse problem and to increase reconstruction quality. Results: The approach used in 1D EPR can only be employed for the reconstruction of small volumes in 2D and 3D EPRs due to numerical instability of the inverse solution. The authors performed EPR measurements of increasing cylindrical volumes and evaluated the condition measure. This showed that a reduction of the inherent symmetry in the EPR methodology is necessary. By reducing the symmetry of the EPR setup, quantitative images of

  17. Post-processing of EPR spectrum from dosimetric substances through filtering of Discrete Fourier Transform

    International Nuclear Information System (INIS)

    Vieira, Fabio P.B.; Bevilacqua, Joyce S.

    2014-01-01

    The use of electron paramagnetic resonance spectrometers - EPR - in radiation dosimetry is known for more than four decades. It is an important tool in the retrospective determination of doses absorbed. To estimate the dose absorbed by the sample, it is necessary to know the amplitude of the peak to peak signature of the substance in its EPR spectrum. This information can be compromised by the presence of spurious information: noise - of random and low intensity nature; and the behavior of the baseline - coming from the coupling between the resonator tube and the sample analyzed. Due to the intrinsic characteristics of the three main components of the signal, i.e. signature, noise, and baseline - the analysis in the frequency domain allows, through post-processing techniques to filter spurious information. In this work, an algorithm that retrieves the signature of a substance has been implemented. The Discrete Fourier Transform is applied to the signal and without user intervention, the noise is filtered. From the filtered signal, recovers the signature by Inverse Discrete Fourier Transform. The peak to peak amplitude, and the absorbed dose is calculated with an error of less than 1% for signals wherein the base line is linearized. Some more general cases are under investigation and with little user intervention, you can get the same error

  18. Synthesis, XRD, TEM, EPR, and Optical Absorption Spectral Studies of CuZnO2 Nanocompound

    Directory of Open Access Journals (Sweden)

    T. Ravindra Reddy

    2014-01-01

    Full Text Available Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are a=3.1 Å and c=3.4786 Å and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM. The size is found to be 100 nm. Uniform bright rings are noticed in the TEM picture suggesting that the nanocrystals have preferential instead of random orientations. The selected-area electron diffraction (SAED pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR. The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, λ, is calculated using the EPR and optical absorption spectral results suggest some covalent bond between metal and ligand. Near infrared (NIR spectra are due to hydroxyl and water fundamentals.

  19. Growth, optical and EPR studies of {sup 151}Eu{sup 2+}:YAG single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Petrosyan, A.G., E-mail: pet@ipr.sci.am [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Asatryan, H.R. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Hovhannesyan, K.L.; Derdzyan, M.V. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Feofilov, S.P. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Eganyan, A.V.; Sargsyan, R.S. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia)

    2017-01-01

    Single crystals of {sup 151}Eu:YAG were grown by the vertical Bridgman method using Eu{sub 2}O{sub 3} with isotopic enrichment of {sup 151}Eu of 97.5%. Additional Hf{sup 4+}or Si{sup 4+} ions were introduced to favor a high concentrations of Eu{sup 2+}. As compared to Eu:YAG with natural isotope composition, the EPR spectra of YAG doped with {sup 151}Eu isotope show a reduced number of hyperfine structure components and a well-resolved structure of a bigger number of electronic transitions. Optical properties of obtained crystals and the effects of heat treatments under oxidizing and reducing conditions are reported. Based on the analysis of Eu{sup 3+} distribution in oxidized Eu,Hf:YAG, in comparison to that in Eu:YAG, the concentration of Eu{sup 2+} in as-grown Eu,Hf:YAG is determined. - Highlights: • YAG:Eu,Hf single crystals containing only {sup 151}Eu isotopes were prepared. • isotopic enriched crystals gave a well-resolved EPR hyperfine structure of Eu{sup 2+} centers. • the redox ratio was followed through the Eu{sup 2+} associated absorption band at 250 nm. • the band intensities at 378 nm correlate with the Eu{sup 2+} concentration.

  20. Gold atoms and clusters on MgO(100) films; an EPR and IRAS study

    Science.gov (United States)

    Yulikov, M.; Sterrer, M.; Risse, T.; Freund, H.-J.

    2009-06-01

    Single gold atoms deposited on single crystalline MgO(1 0 0) films grown on Mo(1 0 0) are characterized by electron paramagnetic resonance spectroscopy as well as IR spectroscopy using CO as probe molecules. In this article we describe the first angular dependent measurements to determine the principal hyperfine components of a secondary hyperfine interaction, namely, with 17O of the MgO. The values determined here are in perfect agreement with theoretical expectations and corroborate the previously reported binding mechanism of Au atoms on the oxygen anions of the MgO terrace. The temperature dependent EPR data reveal an onset of Au atom mobility at about 80 K while the formation of Au particles occurs only above 125 K. By an analysis of the EPR line width in combination with STM measurements it is possible to deduce an increase of the interatomic distance above 80 K. The Au/CO complexes show a somewhat smaller temperature stability as compared to the Au atoms. The observed thermal stability is in perfect agreement with theoretical predictions for CO desorption.

  1. Cathodoluminescence (CL) and electron paramagnetic resonance (EPR) studies of clay minerals

    International Nuclear Information System (INIS)

    Goetze, J.; Ploetze, M.; Goette, T.; Neuser, R.D.; Richter, D.K.

    2002-01-01

    Sheet silicates of the serpentine-kaolin-group (serpentine, kaolinite, dickite, nacrite, halloysite), the talc-pyrophyllite-group (talc, pyrophyllite), the smectite-group (montmorillonite), and illite (as a mineral of the mica-group) were investigated to obtain information concerning their cathodoluminescence behavior. The study included analyses by cathodoluminescence (CL microscopy and spectroscopy), electron paramagnetic resonance (EPR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and trace element analysis. In general, all dioctahedral clay minerals exhibit a visible CL. Kaolinite, dickite, nacrite and pyrophyllite have a characteristic deep blue CL, whereas halloysite emission is in the greenish-blue region. On the contrary, the trioctahedral minerals (serpentine, talc) and illite do not show visible CL. The characteristic blue CL is caused by an intense emission band around 400 nm (double peak with two maxima at 375 and 410 nm). EPR measurements indicate that his blue emission can be related to radiation induced defect centers (RID), which occur as electron holes trapped on apical oxygen (Si-O center) or located at the Al-O-Al group (Al substituting Si in the tetrahedron). Additional CL emission bands were detected at 580 nm in halloysite and kaolinite, and between 700 and 800 nm in kaolinite, dickite, nacrite and pyrophyllite. Time-resolved spectral CL measurements show typical luminescence kinetics for the different clay minerals, which enable differentiation between the various dioctahedral minerals (e.g. kaolinite and dickite), even in thin section. (author)

  2. An improved approach to identify irradiated spices using electronic nose, FTIR, and EPR spectroscopy.

    Science.gov (United States)

    Sanyal, Bhaskar; Ahn, Jae-Jun; Maeng, Jeong-Hwan; Kyung, Hyun-Kyu; Lim, Ha-Kyeong; Sharma, Arun; Kwon, Joong-Ho

    2014-09-01

    Changes in cumin and chili powder from India resulting from electron-beam irradiation were investigated using 3 analytical methods: electronic nose (E-nose), Fourier transform infrared (FTIR) spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The spices had been exposed to 6 to 14 kGy doses recommended for microbial decontamination. E-nose measured a clear difference in flavor patterns of the irradiated spices in comparison with the nonirradiated samples. Principal component analysis further showed a dose-dependent variation. FTIR spectra of the samples showed strong absorption bands at 3425, 3007 to 2854, and 1746 cm(-1). However, both nonirradiated and irradiated spice samples had comparable patterns without any noteworthy changes in functional groups. EPR spectroscopy of the irradiated samples showed a radiation-specific triplet signal at g = 2.006 with a hyper-fine coupling constant of 3 mT confirming the results obtained with the E-nose technique. Thus, E-nose was found to be a potential tool to identify irradiated spices. © 2014 Institute of Food Technologists®

  3. EPR examination of Zn2+ and Cu2+ binding by pigmented soil fungi Cladosporium cladosporioides

    International Nuclear Information System (INIS)

    Buszman, Ewa; Pilawa, Barbara; Zdybel, Magdalena; Wilczynski, Slawomir; Gondzik, Anna; Witoszynska, Teresa; Wilczok, Tadeusz

    2006-01-01

    The purpose of this study was to examine the usefulness of electron paramagnetic resonance spectroscopy (EPR) to estimate zinc and copper ions biosorption from the environment by pigmented soil fungi Cladosporium cladosporioides. The existence of a low amount of pheomelanin, besides eumelanin, in C. cladosporioides samples was proved by the analysis of shape of their EPR spectra. Concentration of o-semiquinone free radicals in crude mycelium was 2.4 x 10 17 spin/g. Changes in free radicals system of C. cladosporioides cultured in the presence of Zn 2+ and Cu 2+ were analysed. Both magnetic and chemical interactions of zinc and copper ions with free radicals in C. cladosporioides melanin were found. Magnetically interacting diamagnetic Zn 2+ ions increased the concentration of o-semiquinone free radicals in melanin existing in C. cladosporioides mycelium, whereas paramagnetic Cu 2+ ions decreased this concentration. Chemical interactions of Zn 2+ and Cu 2+ ions decreased the free radical concentrations in C. cladosporioides melanin. Homogeneously distributed free radicals in C. cladosporioides melanin rise its activity in biosorption processes

  4. EPR investigation of some traditional oriental irradiated spices

    International Nuclear Information System (INIS)

    Duliu, Octavian G.; Georgescu, Rodica; Ali, Shaban Ibrahim

    2007-01-01

    The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and 60 Co γ-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After γ-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 o C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days storage at ambient conditions only irradiated ginger displays a weak signal that differs from those of unirradiated sample. All these factors could be taken into account in establishing at which extent the EPR is suitable to evidence any irradiation treatment applied to these spices

  5. EPR investigation of some traditional oriental irradiated spices

    Energy Technology Data Exchange (ETDEWEB)

    Duliu, Octavian G. [University of Bucharest, Department of Atomic and Nuclear Physics, Magurele, C.P. MG-11, RO-077125 Bucharest (Romania)]. E-mail: duliu@pcnet.ro; Georgescu, Rodica [National Institute for Physics and Nuclear Engineering -Horia Hulubei, C.P. MG-6, RO-077125 Bucharest (Romania); Ali, Shaban Ibrahim [University of Bucharest, Department of Atomic and Nuclear Physics, Magurele, C.P. MG-11, RO-077125 Bucharest (Romania)

    2007-06-15

    The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and {sup 60}Co {gamma}-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After {gamma}-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 {sup o}C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days storage at ambient conditions only irradiated ginger displays a weak signal that differs from those of unirradiated sample. All these factors could be taken into account in establishing at which extent the EPR is suitable to evidence any irradiation treatment applied to these spices.

  6. EPR investigation of some irradiated traditional oriental spices

    International Nuclear Information System (INIS)

    Duliu, Octavian G.; Ali, Ibrahim Shaban; Georgescu, Rodica

    2005-01-01

    The X-band EPR spectra of unirradiated and 60 Co gamma ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), saffron (Crocus sativus L., Iridaceae), and curry have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones, most probably due to the presence of semiquinones, previously reported to have paramagnetic properties. After gamma ray irradiation at absorbed dose up to 11.3 kGy we have noticed in all spices the presence of complex EPR spectra consisting of a superposition of at last two different paramagnetic species whose amplitude increase monotonously with the absorbed dose. A 100 deg. C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that form the initial spectra, but even after 5 h of thermal treatment, the remaining amplitude represents no less than 40% from the initial ones, testifying for a good thermal stability. The presences of initial EPR spectra as well as the remaining amplitude after isothermal annealing are very useful in identifying any irradiation treatment applied to this category of species. (authors)

  7. EPR investigation of some traditional oriental irradiated spices

    Science.gov (United States)

    Duliu, Octavian G.; Georgescu, Rodica; Ali, Shaban Ibrahim

    2007-06-01

    The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and 60Co γ-ray irradiated cardamom ( Elettaria cardamomum L. Maton, Zingiberaceae), ginger (( Zingiber officinale Rosc., Zingiberaceae), and saffron ( Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After γ-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 °C isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days storage at ambient conditions only irradiated ginger displays a weak signal that differs from those of unirradiated sample. All these factors could be taken into account in establishing at which extent the EPR is suitable to evidence any irradiation treatment applied to these spices.

  8. Advances in Probes and Methods for Clinical EPR Oximetry

    Science.gov (United States)

    Hou, Huagang; Khan, Nadeem; Jarvis, Lesley A.; Chen, Eunice Y.; Williams, Benjamin B.; Kuppusamy, Periannan

    2015-01-01

    EPR oximetry, which enables reliable, accurate, and repeated measurements of the partial pressure of oxygen in tissues, provides a unique opportunity to investigate the role of oxygen in the pathogenesis and treatment of several diseases including cancer, stroke, and heart failure. Building on significant advances in the in vivo application of EPR oximetry for small animal models of disease, we are developing suitable probes and instrumentation required for use in human subjects. Our laboratory has established the feasibility of clinical EPR oximetry in cancer patients using India ink, the only material presently approved for clinical use. We now are developing the next generation of probes, which are both superior in terms of oxygen sensitivity and biocompatibility including an excellent safety profile for use in humans. Further advances include the development of implantable oxygen sensors linked to an external coupling loop for measurements of deep-tissue oxygenations at any depth, overcoming the current limitation of 10 mm. This paper presents an overview of recent developments in our ability to make meaningful measurements of oxygen partial pressures in human subjects under clinical settings. PMID:24729217

  9. Peptide-membrane Interactions by Spin-labeling EPR

    Science.gov (United States)

    Smirnova, Tatyana I.; Smirnov, Alex I.

    2016-01-01

    Site-directed spin labeling (SDSL) in combination with Electron Paramagnetic Resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described. PMID:26477253

  10. Development of fire protection standards for the EPR project

    International Nuclear Information System (INIS)

    Frank, H.J.; Kaercher, M.; Wittmann, R.

    2000-01-01

    In 1989 Framatome and Siemens decided by setting up their joint subsidiary NPI (Nuclear Power International) to co-operate in designing a new European Pressurised Water Reactor, the EPR. French and German utilities decided to participate in this project. In parallel to the co-operation on supplier's and utility's side, the French and German safety authorities and safety experts wanted to work closely together in order to harmonise and further develop the outstanding safety standards in France and Germany. An organisation has been set up to elaborate common codes related to the EPR design, at the level of the French design and construction rules (RCC) of the German KTA safety standards and DIN standards for nuclear technology, the so-called EPR technical codes (ETC). In this context the decision was made to develop a new fire protection code, the ETC-F, which should be harmonised between France and Germany. The article gives an insight in the developing process of the ETC-F and an outlook on existing and perhaps further national activities. (orig.) [de

  11. Characterization of beer flavour stability (EPR - spin trapping)

    International Nuclear Information System (INIS)

    Stasko, A.; Liptakova, M.; Malik, F.

    1999-01-01

    The beer flavour stability is coupled with free radical degradation processes. Probably, aldehydes produced during the brewery but also generated by stalling are responsible for beer flavour as well as for its breaking down. The storing beer at the lower temperatures and in the dark place inhibits, and otherwise the rising temperature and illumination accelerate the rate of such radical processes. Beers contain naturally occurring radical scavengers - antioxidants which inhibit such unwanted reactions. Then depleting of scavengers results in the breaking down of the beer stability. EPR spin trapping technique was used as monitor such processes and for characterising so the flavour stability of beer. The probe was temperated at 60 grad C in the cavity of EPR spectrometer in the presence of spin trapping agent, N-tert.-butyl-α-phenyl nitrone (PBN) and EPR spectra were recorded for few hours. After beer antioxidants become depleted, free radicals formed by the beer degradation are scavenged by PBN spin trap and this point is characterised with a dramatically increased concentration of the free radicals trapped

  12. Public debate about the EPR nuclear power plant at Flamanville

    International Nuclear Information System (INIS)

    2005-01-01

    The project of building of he EPR reactor at Flamanville (Manche, France) has been submitted to the public debate. This document includes a presentation of the project and of the rules of the public debate, a synthesis of the file made by the prime contractor (EDF), a synthesis of the collective book of national actors concerned by the project (a group of associations for environment protection, Areva company, the ministries of economy and ecology, Global Chance, association of pro-nuclear ecologists (AEPN), 'Sortir du Nucleaire' (out-of nuclear) network, group of scientists for the information about nuclear (GSIEN), association for the promotion of the Flamanville site (Proflam), French nuclear energy society (SFEN) in association with 'Sauvons le Climat' (let's save climate), regional collective association 'EPR non merci, ni ailleurs, ni ici' (EPR, no thanks, neither elsewhere, nor here), NegaWatt), and 5 detailed books of actors: ACRO (association for the control of radioactivity in Western France), CFDT and CGT syndicates, the economic and social council of Basse Normandie region, and Proflam. (J.S.)

  13. EPR, a GEN 3 Reactor providing a competitive electricity cost

    International Nuclear Information System (INIS)

    Salhi, Othman

    2006-01-01

    Since the very beginning of the development of what was to become the EPR, several European entities were involved. The French and German safety authorities expressed that reinforced safety was compulsory. Additional measures were then included to prevent the occurrence of events likely to damage the core, and reduce the possibility of exposure of operating and maintenance personnel. However, not with standing these safety related features resulting from the requirements of the safety authorities, we will focus today on another group of entities that were key players in EPR development: the Utilities. The Utilities voiced their need for a competitive electricity produced and a competitive nuclear reactor. The tradeoff was then to reach both targets in a unique product: a safer and more competitive NPP. Today, the EPR presents features that enable our clients to compete with the cheapest fossil-based electricity production plants. Increased thermal efficiency is obtained both through a higher steam pressure and through careful optimization of the secondary system thermal cycle

  14. High-frequency EPR of surface impurities on nanodiamond

    Science.gov (United States)

    Peng, Zaili; Stepanov, Viktor; Takahashi, Susumu

    Diamond is a fascinating material, hosting nitrogen-vacancy (NV) defect centers with unique magnetic and optical properties. There have been many reports that suggest the existence of paramagnetic impurities near surface of various kinds of diamonds. Electron paramagnetic resonance (EPR) investigation of mechanically crushed nanodiamonds (NDs) as well as detonation NDs revealed g 2 like signals that are attributed to structural defects and dangling bonds near the diamond surface. In this presentation, we investigate paramagnetic impurities in various sizes of NDs using high-frequency (HF) continuous wave (cw) and pulsed EPR spectroscopy. Strong size dependence on the linewidth of HF cw EPR spectra reveals the existence of paramagnetic impurities in the vicinity of the diamond surface. We also study the size dependence of the spin-lattice and spin-spin relaxation times (T1 and T2) of single substitutional nitrogen defects in NDs Significant deviations from the temperature dependence of the phonon-assisted T1 process were observed in the ND samples, and were attributed to the contribution from the surface impurities. This work was supported by the Searle Scholars Program and the National Science Foundation (DMR-1508661 and CHE-1611134).

  15. Estimation of mean and median pO2 values for a composite EPR spectrum.

    Science.gov (United States)

    Ahmad, Rizwan; Vikram, Deepti S; Potter, Lee C; Kuppusamy, Periannan

    2008-06-01

    Electron paramagnetic resonance (EPR)-based oximetry is capable of quantifying oxygen content in samples. However, for a heterogeneous environment with multiple pO2 values, peak-to-peak linewidth of the composite EPR lineshape does not provide a reliable estimate of the overall pO2 in the sample. The estimate, depending on the heterogeneity, can be severely biased towards narrow components. To address this issue, we suggest a postprocessing method to recover the linewidth histogram which can be used in estimating meaningful parameters, such as the mean and median pO2 values. This information, although not as comprehensive as obtained by EPR spectral-spatial imaging, goes beyond what can be generally achieved with conventional EPR spectroscopy. Substantially shorter acquisition times, in comparison to EPR imaging, may prompt its use in clinically relevant models. For validation, simulation and EPR experiment data are presented.

  16. EPR dosimetry of cortical bone and tooth enamel irradiated with X and gamma rays: Study of energy dependence

    International Nuclear Information System (INIS)

    Schauer, D.A.; Links, J.M.; Desrosiers, M.F.; Le, F.G.; Seltzer, S.M.

    1994-01-01

    Previous investigators have reported that the radiation-induced EPR signal intensity in compact or cortical bone increases up to a factor of two with decreasing photon energy for a given absorbed dose. If the EPR signal intensity was dependent on energy, it could limit the application of EPR spectrometry and the additive reirradiation method to obtain dose estimates. We have recently shown that errors in the assumptions governing conversion of measured exposure to absorbed dose can lead to similar open-quotes apparentclose quotes energy-dependence results. We hypothesized that these previous results were due to errors in the estimated dose in bone, rather than the effects of energy dependence per se. To test this hypothesis we studied human adult cortical bone from male and female donors ranging in age from 23 to 95 years, and bovine tooth enamel, using 34 and 138 keV average energy X-ray beams and 137 Cs (662 keV) and 60 Co (1250 keV) γ rays. In a femur from a 47-year-old male (subject 1), there was a difference of borderline significance at the α = 0.05 level in the mean radiation-induced hydroxyapatite signal intensities as a function of photon energy. No other statistically significant differences in EPR signal intensity as a function of photon energy were observed in this subject, or in the tibia from a 23-year-old male (subject 2) and the femur from a 75-year-old female (subject 3). However, there was a trend toward a decrease (12-15%) in signal intensity at the lowest energy compared with the highest energy in subjects 1 and 3. Further analysis of the data from subject 1 revealed that this trend, which is in the opposite direction of previous reports but is consistent with theory, is statistically significant. There were no efforts of energy dependence in the tooth samples. 16 refs., 7 figs., 5 tabs

  17. Toward the fourth dimension of membrane protein structure: insight into dynamics from spin-labeling EPR spectroscopy.

    Science.gov (United States)

    McHaourab, Hassane S; Steed, P Ryan; Kazmier, Kelli

    2011-11-09

    Trapping membrane proteins in the confines of a crystal lattice obscures dynamic modes essential for interconversion between multiple conformations in the functional cycle. Moreover, lattice forces could conspire with detergent solubilization to stabilize a minor conformer in an ensemble thus confounding mechanistic interpretation. Spin labeling in conjunction with electron paramagnetic resonance (EPR) spectroscopy offers an exquisite window into membrane protein dynamics in the native-like environment of a lipid bilayer. Systematic application of spin labeling and EPR identifies sequence-specific secondary structures, defines their topology and their packing in the tertiary fold. Long range distance measurements (60 Å-80 Å) between pairs of spin labels enable quantitative analysis of equilibrium dynamics and triggered conformational changes. This review highlights the contribution of spin labeling to bridging structure and mechanism. Efforts to develop methods for determining structures from EPR restraints and to increase sensitivity and throughput promise to expand spin labeling applications in membrane protein structural biology. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Solid-state EPR strategies for the structural characterization of paramagnetic NO adducts of frustrated Lewis pairs (FLPs)

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcos de; Magon, Claudio José [Instituto de Física de São Carlos, Universidade de São Paulo, P.O. Box 369, 13560-970 São Carlos, São Paulo (Brazil); Wiegand, Thomas [Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8049 Zürich (Switzerland); Elmer, Lisa-Maria; Sajid, Muhammad; Kehr, Gerald; Erker, Gerhard [Organisch-Chemisches Institut, WWU Münster, Corrensstraße 40, D 48149 Münster (Germany); Eckert, Hellmut, E-mail: eckerth@uni-muenster.de [Instituto de Física de São Carlos, Universidade de São Paulo, P.O. Box 369, 13560-970 São Carlos, São Paulo (Brazil); Institut für Physikalische Chemie, WWU Münster, Corrensstrasse 30, D 48149 Münster (Germany)

    2015-03-28

    Anisotropic interactions present in three new nitroxide radicals prepared by N,N addition of NO to various borane-phosphane frustrated Lewis pairs (FLPs) have been characterized by continuous-wave (cw) and pulsed X-band EPR spectroscopies in solid FLP-hydroxylamine matrices at 100 K. Anisotropic g-tensor values and {sup 11}B, {sup 14}N, and {sup 31}P hyperfine coupling tensor components have been extracted from continuous-wave lineshape analyses, electron spin echo envelope modulation (ESEEM), and hyperfine sublevel correlation spectroscopy (HYSCORE) experiments with the help of computer simulation techniques. Suitable fitting constraints are developed on the basis of density functional theory (DFT) calculations. These calculations reveal that different from the situation in standard nitroxide radicals (TEMPO), the g-tensors are non-coincident with any of the nuclear hyperfine interaction tensors. The determination of these interaction parameters turns out to be successful, as the cw- and pulse EPR experiments are highly complementary in informational content. While the continuous-wave lineshape is largely influenced by the anisotropic hyperfine coupling to {sup 14}N and {sup 31}P, the ESEEM and HYSCORE spectra contain important information about the {sup 11}B hyperfine coupling and nuclear electric quadrupolar interaction. The set of cw- and pulsed EPR experiments, with fitting constraints developed by DFT calculations, defines an efficient strategy for the structural analysis of paramagnetic FLP adducts.

  19. A high-frequency EPR study of a new S = 10 Mn12 single-molecule magnet

    Science.gov (United States)

    Anderson, Norm

    2005-03-01

    We will present a detailed angle-resolved high-frequency EPR study of a recently discovered analog of the Mn12-acetate single-molecule magnet (SMM). Like the acetate, the new complex [Mn12O12(O2CCH2Bu^t)16(CH3OH)4].CH3OH (Mn12-tBuAc), possesses a spin S = 10 ground state and S4 site symmetry. Magnetic measurements also reveal the usual resonant magnetization tunneling steps in the low temperature hysteresis loops. However, we show that the solvent-disorder-induced anomalies reported in the EPR spectra for Mn12-acetate^1 are absent for Mn12-tBuAc. This suggests that Mn12-tBuAc is intrinsically cleaner, and that detailed studies of this compound may reveal important new information concerning the quantum dynamics of large spins. Indeed, our analysis of the EPR line widths suggest that they are close to the intrinsic lifetime broadened limit, which may make it possible to extract information concerning electronic relaxation times (T1 and T2). ^1S. Takahashi et al., Phys. Rev. B 70, 094429 (2004)

  20. Impact of the Enhanced Permeability and Retention (EPR Effect and Cathepsins Levels on the Activity of Polymer-Drug Conjugates

    Directory of Open Access Journals (Sweden)

    Amit K. Rajora

    2014-08-01

    Full Text Available Polymer-drug conjugates have demonstrated clinical potential in the context of anticancer therapy. However, such promising results have, to date, failed to translate into a marketed product. Polymer-drug conjugates rely on two factors for activity: (i the presence of a defective vasculature, for passive accumulation of this technology into the tumour tissue (enhanced permeability and retention (EPR effect and (ii the presence of a specific trigger at the tumour site, for selective drug release (e.g., the enzyme cathepsin B. Here, we retrospectively analyse literature data to investigate which tumour types have proved more responsive to polymer-drug conjugates and to determine correlations between the magnitude of the EPR effect and/or expression of cathepsin B. Lung, breast and ovarian cancers showed the highest response rate (30%, 47% and 41%, respectively for cathepsin-activated conjugates and 31%, 43%, 40%, across all conjugates. An analysis of literature data on cathepsin content in various tumour types showed that these tumour types had high cathepsin content (up to 3835 ng/mg for lung cancer, although marked heterogeneity was observed across different studies. In addition, these tumour types were also reported as having a high EPR effect. Our results suggest that a pre-screening of patient population could bring a more marked clinical benefit.